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<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The current state of process-reactive schizophrenia.? [/INST] Current developments in the process-reactive classification of schizophrenia are examined in the light of diagnosis, paranoid-nonparanoid status, premorbid adjustment, demographic factors, and outcome. Recent studies are reviewed as suggestive of a present focus, and theoretical possibilities are explored. Recommendations are made to include a broader, more complex view of the process-reactive conception, methodological improvements, further theoretical development, and increased research into a variety of promising areas utilizing this framework and facilitating its useful growth as an approach to understanding the totality of schizophrenia. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Quantitative structure-activity relationships in 1-aryl-2-(alkylamino)ethanol antimalarials.? [/INST] A quantitative structure-activity relationship has been formulated for 646 antimalarials acting against P. berghei in mice. The equation developed has 14 terms, 9 of which are indicator variables. The correlation coefficient for the QSAR is 0.898 and the standard deviation is 0.309. The antimalarials are all arylcarbinols of the type X-ArCHOHCH2NR1R2. Sixty different aryl structures, including a variety of heterocyles, are contained in the study. The most important determinate of activity is found to be the electron-withdrawing ability of the substituents X; the hydrophobic character of X and R plays less important roles. Suggestions for more potent analogues are made and the lack of activity of about 100 additional analogues is also considered. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The donation and transplantation of kidneys: should the law be changed?? [/INST] It is now eighteen years on since the Human Tissue Act 1961, but this legislation is still unchanged in England, Scotland and Wales. Ian Kennedy, in this paper, lays before us the law as it is, the problems of its interpretation and his opinion of what government should be doing to help clarify the situation and remove some of the problems which exist daily for the doctors who face the dilemma of seeking consent for transplants at the moment of extreme grief for the surviving spouses or relatives of the patient who has been in his care only moments before. Ian Kennedy suggests that by doing nothing the Department of Health and the government are being both callous and less than honest. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about What is medicine?: towards a philosophical approach.? [/INST] The failure of Western medicine to deal with many of the problems it is currently facing has led to an awareness of the need for a fundamental reappraisal. The way in which medical concepts derived from the nineteenth century have brought technical medical advances in this century and the alliances that medicine has made with statistics and more recently the social sciences, have prevented a questioning of medicine's underlying assumptions. Thus, despite a number of critical initiatives from both within and outside medicine, there has been no coherent development to seriously confront the question 'what is medicine?'. It is suggested that the basis for such a development depends on the return to a philosophical questioning of our conceptual understanding of disease, a subject which has largely been ignored during the past hundred years. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The special affinity of particular types of Proteus mirabilis for the urinary tract.? [/INST] The strains of Proteus species found in significant numbers and as pure cultures in urine from 217 individuals were isolated, identified to species level and typed for proticine production (P type) and proticine sensitivity (S type) to give their P/S type. Urinary-tract infections with Proteus, principally P. mirabilis, were associated with the elderly. Ninety seven distinct P/S types were found but three P/S types P3/S1,8, P3/S1,8,13 and P3/S1,13 were isolated at a much higher frequency (14%) then could be explained from their faecal carriage rate. These types were almost without exception restricted to patients with clinical symptoms of urinary-tract infection and it is suggested therefore that they have some special affinity for the urinary tract. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Escherichia coli K antigen in relation to serum-induced lysis and phagocytosis.? [/INST] The presence of capsular polysaccharides (K antigens) and their relation to phagocytosis and sensitivity to the lytic action of serum of 26 strains of E. coli isolated from stools of healthy volunteers and from blood cultures were studied. Four of 12 strains isolated from stool cultures and 12 (86%) of the 14 strains isolated from blood cultures possessed K antigen. Three of the 12 strains isolated from stool cultures and seven of the 14 isolated from blood cultures were resistant to uptake by polymorphonuclear leucocytes; these resistant strains contained large amounts of K antigen. By contrast 10 strains, three with low amounts of K antigen and seven without detectable amounts of K antigen, were readily phagocytosed. Thus it appears that K antigen renders E. coli resistant to phagocytosis. Only four (15%) of the 26 strains were sensitive to serum lysis and there was no correlation between the presence of K antigen and the resistance to serum lysis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Experience with radial haemolysis for rubella antibody screening.? [/INST] Twelve hundred and thirty three sera were tested in parallel by the single radial haemolysis (SRH) and by the simplified haemagglutination inhibition (HAI) technique in routine use in this laboratory. In 1203 (97.6%) of these sera the results were in agreement. The remaining 30 (2.4%) sera were re-tested by both methods because on initial testing the results obtained by the two methods did not agree; only three specimens remained discrepant. The SRH is a simple test to perform and discriminates clearly between positive and negative sera. It is particularly suitable for screening large batches of sera. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of freezing and storage in liquid nitrogen on the viability and growth of Mycobacterium leprae.? [/INST] The effects of rapid and slow rates of freezing in liquid nitrogen, storage in liquid nitrogen for 12 months, and the rate of subsequent thawing on the viability and growth of M. leprae in the mouse footpad were studied. Some loss of viability of M. leprae was detected, and this was found to be associated with the freezing process, rather than with storage or thawing. Slow freezing was less deleterious than quick freezing, with a loss of viability of 90% compared with 98%. The growth pattern of M. leprae was unaffected except for a delay in the appearance of growth caused by the loss of viability, though there was some evidence of an increased lag phase of one strain, possibly due to the repair of sub-lethally damaged organisms. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The variable response of bacteria to excess ferric iron in host tissues.? [/INST] The enhancement by exogenous ferric iron, both systemic and local, of the infectivity of 120 strains of bacteria, representing 17 genera, was measured in the skin of guinea-pigs. Systemic iron enhanced only 23% of 115 strains, and local iron 49% of 71 strains. Systemic iron, by an apparently anti-inflammatory action, depressed the size of lesions produced by 27 of the non-enhanced strains from nine of the genera tested. For most strains, the degree of enhancement was small, ranging from 2- to 8-fold, and often evident only with the more effective local iron; among these were some near-saprophytes like Mycobacterium phlei, M. smegmatis, Bacillus cereus and Clostridium bifermentans. Substantial enhancement, from 14- to 50-fold, was observed with the more pathogenic among the strains tested: namely BCG, Corynebacterium ovis, C. murium, Listeria monocytogenes, Erysipelothrix rhusiopathiae, Cl. perfringens, Cl. septicum, Cl. oedematiens, and some strains of Klebsiella spp., Proteus spp. and Aeromonas hydrophila. The enhancement of BCG by a single dose of iron given locally with the inoculum was only feebly manifest after 7 days, but substantial after 14--19 days, indicating the decisive effect of interference with an early humoral defence on the establishment of chronic infection some time later. Insofar as guinea-pigs whose antibacterial defences are lowered by substantial amounts of exogenous iron in the circulation represent human subjects at risk of infection because of clinical states characterised by excess of available iron, the results of the survey suggest that only a minority among the environmental bacteria can take advantage of the decreased resistance associated with such states; but that this minority is likely to include the more virulent strains in the environment. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of 5-fluorocytosine on the blastospores and hyphae of Candida albicans.? [/INST] In Candida albicans the continued increase in dry weight, in cell volume and in hyphal length during 5FC treatment is mainly due to increased amount of carbohydrate despite the decreased amounts of nucleic acids. Incorporation studies with 32PO4 (for RNA) in C. albicans and with 3H-thymidine-monophosphate (for DNA) in a thymidine-utilising strain of Saccharomyces cerevisiae have shown that the decreased amounts of nucleic acids were due to an inhibition of synthesis of RNA and DNA by 5FC. Nuclear-staining techniques on the hyphal phase of C. albicans showed that 5FC inhibits nuclear division. The changes in amounts of protein during 5FC treatment do not wholly explain the changes in cell size although 14C-histidine incorporation experiments showed that protein synthesis continued in the presence of 5FC. 14C-glucose incorporation in the presence of 5FC showed an initial accelerated synthesis of carbohydrate with a maintained level of synthesis after 16 h. This abnormal pattern of synthesis correlates with the increase in amount of carbohydrate and in cell size and hyphal elongation. 5FC inhibits DNA synthesis, and all manifestations of unbalanced growth that culminate in the cell volume changes appear to be a consequence of that inhibition. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Histologic investigation of glycol methacrylate embedded chick embryonic tissue.? [/INST] Specific light microscopic investigations (i.e. histochemical) of early embryonic material have always been beset by difficulties in processing and obtaining tissue sections of good quality. The advent of glycol methacrylate (GMA) as an embedding medium now provides a means to overcome these inherent problems with this tissue. Investigations were carried out to assess the histological results produced by different fixatives and times of fixation of GMA embedded 5-day chick embryonic tissue. Optimum cellular preservation of all tissues occurred following fixation in a mixture of acetic acid, 95% ethanol and neutral buffered formalin (AAF). With the procedures described in this study, a new method is available for more comprehensive examination of all types of early embryonic material. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A technique for illuminating early chick embryos in ovo with a glass rod as a light guide.? [/INST] A glass rod mounted on a microscope condenser acts as a light guide through the yolk of a fertile hen's egg. Two apertures must first be made in the shell: the one below covered with plastic film which seals around the rod; the one above covered with a glass coverslip to allow microscopic observation of the embryo. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Localization of Escherichia coli RNA polymerase binding sites on bacteriophage S13 and 0X174 DNAs by electron microscopy.? [/INST] Complexes between Escherichia coli RNA polymerase and bacteriophage S13 and phage phiX174 replicative form III DNAs have been shown to form at specific locations on the phage genomes. The major locations on S13 have been mapped at 8 to 10 and 92 to 96% of the genome length, starting from the unique Pst I cleavage site. The locations correspond to the beginnings of genes D and B, respectively. Four minor locations map at 18 to 22, 28 to 32, 50 to 56, and 70 to 74% of the genome. The 70 to 74% site corresponds to the beginning of the A gene. The major locations on phiX174 are at 8 to 10, 50 to 54, and 92 to 94% of the genome. The 50 to 54% site is at the start of the H gene and has an equivalent minor site on S13, but it is not a promoter site. Three minor sites on phiX174, at 20 to 24, 26 to 32, and 68 to 74% of the genome, correspond to sites on S13. The data confirm the locations of sites identified by restriction fragment binding experiments (E. Rassart and J. H. Spencer, J. Virol. 27:677--687, 1978) and the assignment of putative promoters at the start of genes A, B and D. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Involvement of DNA gyrase in replication and transcription of bacteriophage T7 DNA.? [/INST] Growth of bacteriophage T7 is inhibited by the antibiotic coumermycin A1, an inhibitor of the Escherichia coli DNA gyrase. Since growth of the phage is insensitive to the antibiotic in strains containing a coumermycin-resistant DNA gyrase, this enzyme appears to be required for phage growth. We have investigated the effect of coumermycin on the kinetics of DNA, RNA, and protein synthesis during T7 infection. DNA synthesis is completely inhibited by the antibiotic. In addition, coumermycin significantly inhibits transcription of late but not early genes. Thus, E. coli DNA gyrase may play an important role in transcription as well as in replication of T7 DNA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Chromosomal location of the attachment site for the PA-2 prophage in Escherichia coli K-12.? [/INST] The chromosomal attachment site for the PA-2 prophage is located between dsd and aroC at the approximately 50 min on the Escherichia coli K-12 genetic map. The attachment site is designated attPA-2. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Construction and characterization of the hybrid bacteriophage lambda Charon vectors for DNA cloning.? [/INST] Twenty hybrid lambda phages especially designed for molecular cloning have been constructed and named Charon phages. These phages differ in the ranges of sizes of DNA fragments that may be inserted, by the selections and screens which may be used to isolate and detect the incorporation of cloned fragments, by the way transcription of the cloned fragment may be controlled, by the different restriction enzymes that can be used for cloning, by the phage immunities that may be employed for controlling replication and transcription, and by the biological safety features that they contain. The crosses used to produce the vectors are described, and their genealogy is discussed. The structure of each vector has been verified by genetic tests, by DNA length determinations, by electron micrographic analysis of DNA heteroduplexes, and by gel electrophoresis of restriction enzyme digests. In the course of these constructions, a new EcoRI site was found in a derivative of lambda Aam32Bam1 which maps very near the left cohesive end of lambda. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about In situ flushing of donor kidneys: its technique and rationale.? [/INST] In situ flushing of kidneys through an isolated segment of aorta was done on mongrel dogs. The 500 cc cold perfusate at 3 to 4C (delivered in 6 minutes) effectively cooled the kidneys to about 15C. This simplified technique of in situ flushing, its usefulness and rationale are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Free full thickness skin graft urethroplasty: current technique.? [/INST] We present details of our current techniques for skin graft urethroplasty. We believe that careful attention to the details of these operative techniques is important to their success. The changes from our previous reports include: 1) preparation of patch grafts with rounded ends, 2) preparation of tube grafts with fishmouth spatulation, 3) fixation of the stent catheter to the anterior abdominal wall, 4) leaving a stent catheter inlying for 2 weeks and replacing with a smaller catheter if a voiding cystourethrogram shows extravasation, 5) fixation of the graft during preparation by dermatome adhesive, 6) irrigation of the wound with irrigant before closure and 7) urodynamic flow study for non-invasive postoperative followup. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Intercostal nerve block with thoracoabdominal incision.? [/INST] A double-blind study was done on 30 patients undergoing thoracoabdominal incisions for retroperitoneal lymphadenectomy in testicular carcinoma to determine the effect of intraoperative intercostal nerve block with bupivacaine. The postoperative pain, day of ambulation and day of oral fluid intake were analyzed. In this homogeneous group we found a significant reduction in the amount of postoperative analgesia required but no difference in the day of ambulation or fluid intake. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Massive renal angiomyolipoma: preoperative infarction by balloon catheter.? [/INST] A case of a renal angiomyolipoma supplied by 2 renal arteries is reported. Preoperative, percutaneous transluminal infarction by a balloon catheter facilitated surgical removal of this massive neoplasm. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Prophylaxis of streptococcal infections and rheumatic fever: a comparison of orally administered clindamycin and penicillin.? [/INST] Orally administered clindamycin and penicillin were compared for effectiveness in preventing streptococcal infections in 202 randomly assigned patients with previous rheumatic fever (RF). Among 143 patients aged 21 years or younger observed for 537 patient-years, the number of streptococcal infections (and number per patient-year) was 23 (0.084) in the penicillin group and 12 (0.045) in the clindamycin group. Excluding uncooperative patients, the rate of streptococcal infection remained less, though not statistically significant, in the clindamycin group than in the penicillin group. Two RF recurrences occurred in the penicillin group, and no recurrence occurred in the clindamycin group. Clindamycin was well tolerated except for possible mild gastrointestinal symptoms in six patients. Clindamycin can be substituted for penicillin for RF prophylaxis when there is allergy to penicillin or concern about the development of penicillin-resistant mouth organisms. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Ticrynafen and hydrochlorothiazide. A double-blind study of antihypertensive properties with an open crossover.? [/INST] Twenty-eight patients completed a double-blind study of the antihypertensive effects of ticrynafen compared with those of hydrochlorothiazide. The results of blood pressure reduction were comparable in the two groups. After six months, 12 patients were crossed over to ticrynafen therapy from hydrochlorothiazide. They maintained their blood pressure reduction. The most striking difference between the two groups was in the uric acid response. The uric acid level in the patients receiving hydrochlorothiazide therapy rose from a baseline of 5.9 to 7.5 mg/dL (normal range, 3.0 to 8.0 mg/dL). The uric acid level of those patients receiving ticrynafen therapy decreased from a baseline of 6.4 mg/dL to a low of 3.3 mg/dL. In view of ticrynafen's appreciable antihypertensive and uric-acid-lowering effects, it appears to be a useful new antihypertensive drug. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Flap reconstruction in patients with head and neck cancer: techniques and results.? [/INST] Patients who are treated by surgery, radiotherapy, or any combination thereof may suffer from complications in wound healing or tumor recurrence which necessitate reconstruction of repair utilizing tissue brought in from other parts of the body. The majority of patients, who required flap reconstruction for primary repair or for a complication of their surgery, had their primary lesion in the supraglottic larynx or inferior hypopharynx. More than two-thirds of the flaps elevated were for fistula repair. Five year survival in this group of patients was lower than in those patients with uncomplicated postoperative courses, although the quality of life for the survivors in both groups was not significantly different. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Plasmid replication functions. II. Cloning analysis of the repA replication region of antibiotic resistance plasmid R6-5.? [/INST] R6-5 is a low copy number, conjugative, FII incompatibility group plasmid that has a molecular length of 102 kb and that specifies resistance against several antibiotics (chloramphenicol, fusidic acid, kanamycin, streptomycin and sulphonamide) and mercury salts. By means of in vitro cloning procedures, mini plasmids have been generated that contain a DNA segment from the essential region of R6-5 that is only 2.6 kb in length. This DNA segment, which consists of two PstI fragments that are adjacent in the parent plasmid, carries all genes and sequences required for the regulated replication and incompatibility properties of R6-5, including its origin of replication, OriV, an essential function that has been designated RepA, and the copy control function, Cop. Three different polypeptides, having monomer molecular weights of 23,000, 10,000 and 9,500 daltons, are synthesized in detectable quantities by minicells carrying pBR322 hybrid plasmids that contain DNA segments from the R6-5 essential region. A spontaneous deletion derivative of a pBR322 hybrid plasmid that carries the R6-5 origin of replication was isolated. Heteroduplex analysis of this derivative plasmid indicates that the deleted DNA segment carries the R6-5 replication origin and that its termini consist of short inverted repeat sequences. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Inserted sequence in the mitochondrial 23S ribosomal RNA gene of the yeast Saccharomyces cerevisiae.? [/INST] The sequence organization of the yeast mit-DNA region carrying the large ribosomal RNA gene and the polar locus omega was examined. Hybridization studies using rho- deletion mutants and electron microscopy of the heteroduplexes formed between 23S rRNA and the appropriate restriction fragments, lead to the conclusion that the 23S rRNA1 gene of the omega+ strains is split by an insertion sequence of 1,000-1,100 bp. In contrast, no detactable insertion was found in the 23S rRNA gene of the omega- strains. The size and the location of the insert found in the 23S rRNA gene of the omega+ strains appear to be identical to those of the sequence delta which had previously been found to characterize the difference (at the omega locus) between the mitDNA of the wild type strains carrying the omega+ or omega- alleles (Jacq et al., 1977). </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Plasmid replication functions. III. Origin and direction of replication of a "mini" plasmid derived from R6-5.? [/INST] Replicating DNA molecules of the mini R6-5 plasmid, pKTO71, were purified by equilibrium centrifugation in two successive ethidium bromide-caesium chloride gradients, converted to linear forms by cleavage with either HindIII or BglII restriction endonuclease, and examined in the electron microscope. Determination of the replication fork positions in 65 replicating molecules demonstrated that replication is initiated at a unique location on the plasmid and that it proceeds uni-directionally from this site. The direction of replication is such that the origin-proximal BglII cleavage site is replicated late or, in the case of the parent R6-5 plasmid, is such that the R-determinant region of the molecule is replicated early. The origin of replication, located by these experiments at R6-5 coordinate 98.6 kb, is clearly distinct from that of the R6-5 incompatibility determinant which has been shown to be located on an adjacent PstI-generated DNA fragment whose termini have R6-5 coordinates 96.8 and 97.9 kb. This result indicates that the incompatibility function is not an origin DNA sequence. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Introduction of an active enzyme into permeable cells of Escherichia coli: acquisition of ultraviolet light resistance by uvr mutants on introduction of T4 endonuclease V.? [/INST] Plasmolysed cells of Escherichia coli N212 (uvr A recA) acquired ultraviolet resistance when the cells were exposed to high concentrations of T4 endonuclease V. With increasing concentrations of T4 enzyme, survivals of plasmolysed cells after ultraviolet irradiation increased while colony-forming ability of unirradiated plasmolysed cells was not significantly affected by the enzyme treatment. Under appropriate conditions more than 200 fold increase in survivals was observed. When plasmolysed cells were treated with a pre-heated enzyme preparation or enzyme fractions derived from T4v1 (endonuclease V-deficient mutant)-infected cells, only little or no reactivation took place. Permeabilization of cells prior to the enzyme treatment was essential for the effective reactivation. Treatment of intact cells with the T4 enzyme did not cause any reactivation. Cells treated with 20 mM EGTA or 50 mM CaCl2 in cold were reactivated to certain extents by the enzyme, but the extents of the reactivation were far less compared to those of plasmolysed cells. Plasmolysed cells of strains carrying a mutation in one of uvrA, uvrB and uvrC genes were reactivated by introduction of T4 endonuclease V, as was the uvrA recA double mutant. UvrD mutants were also reactivated, but rather slightly. However, wild type strain as well as strains having a mutation in recA or polA gene were not reactivated. From these results it was suggested that T4 endonuclease V, taken up into permeable cells, can function in vivo to replace defective functions, which are controlled by the uvr genes. The conditions established in the present study may be used for introduction of other proteins into viable bacterial cells. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Studies of viable T4 bacteriophage containing cytosine-substituted DNA (T4dC phage). II. Cleavage of T4dC DNA by endonuclease SalI and bam HI.? [/INST] Digestion of non-glucosylated and cytosine-substituted T4 phage (T4dC) DNA with SalI restriction endonuclease showed that the DNA had nine SalI-sensitive sites. There were eight SalI sites in DNA from a strain which had a deletion in the rII-denB-ndd region. The comparison of two digestion patterns indicated that one of the SalI-sensitive sites was present in the deleted region and that the SalI-F fragments (8.4 x 10(6) daltons) was located adjacent to the SalI-C or SalI-D fragments (15.5 x 10(6) daltons) on the T4 chromosome. The DNA gave no detectable cleavage product when digested with BamHI endonuclease alone, while, when digested successively with BamHI and SalI, the DNA yielded two new digestion products in place of one fragment formed by SalI alone. The BamHI-sensitive site was in the SalI-A fragment (25.2 x 10(6) daltons). The usefulness of this information for making cleavage maps of T4 phage chromosome is discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Degradation of Escherichia coli DNA: evidence for limitation in vivo by protein X, the recA gene product.? [/INST] DNA is more extensively degraded after it is damaged in recA mutants of E. coli than in wild type cells. All data presented here are consistent with the recA gene product, protein X, being an inhibitor of nalidixic acid induced degradation of the bulk DNA (but not of newly replicated DNA). Production of protein X also is correlated with appearance of various "S.O.S." repair functions. Evidence was obtained by comparing the rates of protein X synthesis and solubilization of uniformly-labeled DNA in intact cells, incubated in the presence of nalidixic acid. A set of mutants at the lexA locus produced protein X at different rates and degraded their DNA at rates which were inversely correlated to their rates of protein X production. A low concentration of rifampicin quite specifically inhibited protein X production by wild type E. coli, and allowed more rapid DNA degradation. After the DNA was damaged by the incubation of cells in the presence of nalidixic acid, cells preloaded with protein X degraded their DNA more slowly. We propose that protein X could protect DNA against degradation by binding to single-stranded regions, thereby inhibiting nuclease action. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The use of sym-triazine trichloride in RNA-protein cross-linking studies with Escherichia coli ribosomal subunits.? [/INST] The reagent sym-triazine trichloride is used as a bifunctional reagent to generate RNA-protein cross-links within intact ribosomal subunits from E. coli. The reaction takes place in a stepwise manner, involving substitution of one chlorine atom at 12 degrees and pH 8, and substitution of the second at 40 degrees and pH 6. The cross-linked proteins are analysed by two-dimensional electrophoresis, and the existence of a stable cross-linkage is demonstrated by isolating protein-oligonucleotide complexes from 32P-labelled subunits. The proteins cross-linked are S3 and S4 in the 30S subunit, and L2 in the large subunit, together with smaller amounts of other proteins. The reagent should prove useful in topographical studies of the E. coli ribosome as it is a rigid molecule and generates very short cross-links. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Inhibition of growth by imidazol(on)e propionic acid: evidence in vivo for coordination of histidine catabolism with the catabolism of other amino acids.? [/INST] Imidazole propionic acid (ipa), a gratuitous inducer of the histidine-utilization (hut) system in Salmonella typhimurium, inhibits the organism's growth on succinate minimal medium. Induction of the hut system is necessary, but not sufficient, to cause inhibition. A study of the ability of single amino acids to relieve ipa-restricted growth suggests that insufficient glutamate is the cause of slow growth. The inhibition of growth by imidazolone propionic acid (iopa), an intermediate in the catabolism of histidine to glutamate, is similar to that by ipa. Studies using 2, 3, 5-triphenyl tetrazolium chloride plates to examine amino acid catabolism suggest that accumulation of ipa or iopa leads to inactivation of aspartate amino-transferase (AAT). This interpretation is supported by studies of an Escherichia coli mutant lacking AAT. The mutant grows poorly on succinate minimal medium, and the poor growth is relieved by the same amino acids that relieve ipa- and iopa-restricted growth. These and other findings are discussed in terms of coordination of the histidine-utilization system with enzymatic activities involved in the catabolism of other amino acids. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about X-ray sensitivity of Escherichia coli lysogenic for bacteriophage P2.? [/INST] Strains of Escherichia coli C or K lysogenic for the non-inducible phage P2 show a lower survival following X-ray irradiation as compared to nonlysogenic strains. This difference in X-ray sensitivity is not accompanied by a significant difference in X-ray induced mutability. The capacity of X-irradiated P2 lysogens to multiply any of a number of unirradiated infecting phages is severely impaired. These effects of X-ray treatment can be most simply explained as a consequence of the fact that protein and RNA syntheses are strongly inhibited in P2 lysogens after X-irradiation. All the above events specifically occurring in X-rayed P2 lysogens are dependent on the P2 gene old. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Regulation of RNA synthesis in yeast. III. Synthesis during the cell cycle.? [/INST] Centrifugal elutriation was used to separate cells in different stages of the cell cycle from a culture of Saccharomyces cerevisiae in balanced exponential growth. The rate of DNA and RNA synthesis was determined using a pulse--long-term label technique that is capable of distinguishing between exponential, linear, and periodic variations in the rate of synthesis through the cell cycle. It was found that while the rate of DNA synthesis varies periodically through the cell cycle, the rate of synthesis of mRNA, rRNA, and tRNA increases exponentially through the cell cycle. The implications of these findings for the control of RNA synthesis are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Genetics of ribosomal protein methylation in Escherichia coli. III. Map position of two genes, prmA and prmB, governing methylation of proteins L11 and L3.? [/INST] Two genes governing ribosomal protein methylation have been located on the map of Escherichia coli by conjugation and transduction crosses between wild-type and prm (protein methylation) mutants. The Prm phenotype of recombinants was determined by an in vitro assay of methylgroups incorporation into protein. Gene prmA, governing methylation of protein L11 is situated at minute 71 on the map and is cotransduced with aroE (30%) and with rpsL (5%). Gene prmB, governing methylation of protein L3 is at minute 50, very close to aroC (98.5% co-transduction). A cold-sensitive phenotype was found associated with mutation prmB and was used to score a large number of recombinants in a three factor cross. The results of this cross suggest the order aroC -prmB - purF. The striking symmetrical clustering of aro, prm and rim (ribosome maturation) genes is discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Analysis of rpsD mutations in Escherichia coli. I. Comparison of mutants with various alterations in ribosomal protein S4.? [/INST] Streptomycin-independent revertants were selected from streptomycin-dependent mutants. Twenty-five out of 150 such revertants were temperature sensitive. Ribosomal proteins from 18 temperature-sensitive and 10 temperature-insensitive revertants were analysed by SDS-polyacrylamide gel electrophoresis. Seventeen of the former but none of the latter category showed an alteration of protein S4. The mutated rpsD allele of 6 temperature-sensitive revertants was transduced into a rpsL+ strain. In all cases an increased suppressibility of T4 amber phages was observed. Such suppressibility was not observed in the original rpsD, rpsL strains. All 18 temperature-sensitive mutants were disturbed in the processing of 17s to 16s RNA at non-permissive temperature and the accumulated 17s RNA was degraded. Temperature-insensitive rpsD revertants could be isolated, which had gained a second alteration in S4. Such revertants, which had lost the temperature-sensitive property, were also unable to suppress growth of T4 amber phages. It is concluded that temperature-sensitive growth, inability to process 17s RNA and to assemble 30S ribosomes at non-permissive temperature as well as increased translational ambiguity are highly correlated properties in rpsD mutants. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Analysis of rpsD mutations in Escherichia coli. II. Physiology of some representative mutants.? [/INST] The effects of ribosomal ambiguity mutations (ram A-) on the assembly of ribosomal 30S subunits in Escherichia coli were studied in some representative mutant strains. It was found that the inability of these strains to produce active 30S subunits at nonpermissive temperatures is correlated with a halt in the accumulation of protein S4. It is demonstrated that 30S-precursor particles lacking this protein accumulate and break down at nonpermissive temperatures and that most of the 30S proteins as well as the 17S RNA constituting these particles are similarly unstable. These findings are discussed and related to the finding that merodiploid strains containing genes for both mutant and wild type protein S4 do not accumulate the mutant form of the protein. Experiments indicating that ribosomal precursor particles are associated with polysomes are presented. The implications of these findings are discussed and it is suggested that the assembly of ribosomes is tightly coupled to the synthesis of ribosomal proteins. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Analysis of rpsD mutations in Escherichia coli. III. Effects of rpsD mutations on expression of some ribosomal protein genes.? [/INST] Relative rates of production and steady state levels of ribosomal proteins were determined in a temperature sensitive rpsD (S4) mutant of Escherichia coli. Some proteins (S4, S12, S13) were overproduced in the mutant at permissive temperature but steady state levels of all examined ribosomal proteins were normal. In a rpsD+/rpsD+ homodiploid strain the relative rates of production of ribosomal proteins were not affected by the increased gene dose. In a rpsD+/rpsD heterodiploid strain only wild type, but not mutant S4, was found. In such a strain S4, S7, S12 and probably S13 is overproduced. It is implied that S4 is involved in the regulation of expression of proximal genes of the two transcriptional units including the genes coding for S4 itself and S12, respectively. A degradation system for ribosomal proteins, which is rapid enough to be of regulatory significance, is demonstrated. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about W-reactivation of phage lambda in recF, recL, uvrA, and uvrB mutants of E. coli K-12.? [/INST] W-reactivation is reduced by recF143 and recF144 mutations and is undetectable if a second mutation at either the uvrA or uvrB locus is combined with recF143. The uvrA and uvrB mutations alone block W-reactivation partially. A recL152 mutation also partially blocks W-reactivation by itself. In combination with a uvrB5 mutation, recL125 blocks W-reactivation completely but in combination with recF143, significant residual W-reactivation ability remains. We suggest that the phenomenon of W-reactivation is the result of at least two modes or pathways. The observation that recF143 uvrB5 and recF143 uvrA6 strains permit normal levels of mutagenesis (Kato et al., 1977) but completely block all W-reactivation leads us to suggest further that the mechanism(s) of W-reactivation is at least partly different from that of UV mutagenesis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Deletion mapping of the ilvGOEDAC genes of Escherichia coli K-12.? [/INST] A set of lambdadilv phage has been examined that carry overlapping segments of isoleucine-valine structural and regulatory genes derived from the ilv cluster at 83 min on the Escherichia coli K-12 chromosome. The ilv genes present in these phage, and their order, have been determined by transduction of auxotrophs, escape synthesis, and deletion mapping. The order of ilv genes in the phage, and hence the order in the host chromosome, was found to be ilvG-ilvO-ilvEDA-ilvC. Lysogens containing lambdadilv phage were constructed for dominance analysis of regulatory mutations in the ilvO and ilvA genes. The ilvO671 allele is cis-dominant to ilvO+, while the ilvA538 allele is trans-recessive to ilvA+. Thus, the ilvO gene, that is identified by cis-dominant regulatory mutations that result in increased ilvG and ilvEDA expression, is situated between and may be contiguous with ilvG and ilvEDA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mutations affecting the formation of acetohydroxy acid synthase II in Escherichia coli K-12.? [/INST] Genetic mapping experiments have established that two recently isolated valine-resistant mutants of the K-12 strain of Escherichia coli have lesions lying between ilvE and rbs. These lesions allowed expression of the ilvG gene, specifying the valine-insensitive acetohydroxy acid synthase (synthase II) and an increased expression of the ilvEDA operon. In this respect, they resembled an earlier described ilvO lesion that was reported to lie between ilvA and ilvC. All three lesions were cis-dominant in cis-trans tests. Reexamination of the earlier studied ilvO lesion revealed that it, too, lies between ilvE and rbs. Valine-sensitive derivatives with lesions presumed to be in ilvG were selected from each of the valine-resistant strains. In two of the valine-resistant strains, the ilvG mutations were on the rbs side of ilvO, indicating a gene order rbs-ilvG-ilvO-ilvE-ilvD-ilvA-ilvC. In one of the recently isolated valine-resistant stocks, however, the apparent ilvG mutation was found to be between ilvE and the aline resistance marker. This finding suggests that either ilvO and ilvG mutations are interspersed or there is another locus, ilvR, that behaves phenotypically like ilvO and which lies between ilvG and rbs. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mutants of Escherichia coli defective in the degradation of guanosine 5'-triphosphate, 3'-diphosphate (pppGpp).? [/INST] A new class of mutants of E. coli exhibiting altered metabolism of ppGpp and pppGpp has been isolated, and mapped at a locus designated gpp, near min 83 on the genetic map. These mutants accumulate elevated levels of pppGpp during amino acid starvation or carbon source downshift, and exhibit a reduced rate of pppGpp degradation in vivo. The in vitro evidence suggests that the gpp mutants are defective in a 5'-nucleotidase, which specifically hydrolyzes pppGpp to ppGpp. Certain combinations of gpp and spoT mutations are inviable. A gpp spoT double mutant, constructed by employing a leaky spoT mutation, was found to have a slower rate of pppGpp degradation than the gpp mutant alone. This result indicates that spoT also participates in pppGpp degradation. The inviability of certain gpp spoT combinations is attributed to the inability of the double mutants to degrade pppGpp. This is supported by the observation that selection for increased growth rate on the double mutant results in the recovery of relA mutations. Various effects of the gpp mutation upon the pppGpp and ppGpp pools provide additional support for a scheme in which pppGpp is the major precursor of ppGpp. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Genetic organization of the E. coli chromosome around the structural gene for initiation factor IF3 (infC).? [/INST] A set of lambda transducing phages carrying varying lengths of the E. coli chromosome around the structural gene for initiation factor IF3 (infC) was derived from lambda p2 which is known to carry, besides infC, the structural genes for the alpha subunit of phenylalanyl-tRNA synthetase (pheS), the beta subunit of phenylalanyl-tRNA synthetase (pheT) and the structural gene for threonyl-tRNA synthetase (thrS). The E. coli coding content of these derived phages was analysed by genetic complementation of a set of mutants and by SDS-polyacrylamide gel analysis of the proteins synthesized in UV irradiated cells infected with these phages. The segregation pattern of the different genes among these derived phages indicates that the order of the genes is pheT - pheS - "P12" - (infC, thrS) where infC is probably between "P12" and thrS. "P12" is the structural gene of a 12,000 molecular weight unidentified protein. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Investigations of the F conjugation gene traI:traI mutants and lambdatraI transducing phages.? [/INST] A series of traI point and deletion mutants of Flac, and a traM mutant, were characterised. Complementation tests with an amber Flac traI mutant confirmed their genotypes, and in addition all the traI mutants, but not the traM mutant, were complemented by pRS31 (PSC101 traDI) and EDlambda109 (lambdatraI). Judging from the efficiencies of plating of F-specific phages, none of the mutations affected pilus formation. The traI products of F and of the F-like plasmid R1 were interchangeable with each other but not with that of R100, while the traM product of F could not be replaced by those of R1 or of R100. Neither traI nor traM were needed for conjugal transfer of ColE1. Three lambda transducing phages carrying traI were isolated by in vivo or in vitro techniques, and characterised by genetic complementation tests, by analysis of the fragments produced by restriction endonucleases, and by measurement of heteroduplex molecules. The genetic structures together with the sizes and F coordinates, of the transfer regions carried by the phages were thereby determined. Comparison of the proteins synthesised in UV-irradiated cells by one of the lambdatraI phages with those made by a derivative carrying an amber traI mutation, allowed the traI product to be identified as a protein of molecular weight 174,000. In addition, the molecular weights of the traD (84,000), traS (18,000), and traT (25,000) products made by the lambdatraSTD1 phage EDlambda107 were measured. The possible roles of the traI and traM products in conjugation are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Analysis of lincomycin resistance mutations in Escherichia coli.? [/INST] High level lincomycin resistant strains of Escherichia coli were isolated and screened for altered ribosomal proteins and functions. Amongst 58 strains investigated by electrophoresis one had an altered ribosomal protein S7, another one a mutated L14 and two showed altered L15 proteins. A correlation between these alterations and lincomycin resistant growth could not be demonstrated by genetic analysis for any of the mutants. In vitro, however, extracts from the two L15 mutants were less sensitive to inhibition by the drug. A gene locus (linR) responsible for the lincomycin resistance phenotype was mapped at min 30 of the Escherichia coli chromosome near tyrR; it seems to be identical to the previously described linB locus (Apirion, 1967); however, in contrast to these reports it does not seem to alter any ribosomal function. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Individual messenger RNA half lives in Saccharomyces cerevisiae.? [/INST] We have measured the decay half-life of functional messenger RNA (mRNA) for some thirty different proteins in the yeast Saccharomyces cerevisiae. Production of newly synthesized mRNA was halted by raising the temperature of a culture of a temperature-sensitive mutant, ts 136. Aliquots of this culture were pulsed-labelled with [35S]-methionine at various times after the temperature shift and the radioactive proteins separated on the two-dimensional gel electrophoresis system of O'Farrell. We find a range in the decay half lives of individual mRNA species which varies from 3.5 min to greater than 70 min. We find three general classes of decay curves, (a) simple exponential (first order); some of these showed a shoulder before onset of exponential decay; (b) bi-component or multi-component concave upward; (c) initial stimulation of rate of mRNA synthesis, followed by virtually undetectable decay. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The half-life of mRNA in Saccharomyces cerevisiae.? [/INST] The decay kinetics of mRNA was studied in a yeast temperature-sensitive mutant, ts136, which is defective in cytoplasmic RNA production at 37 degree C. The disappearance of the synthetic capacity of mRNA was determined by withdrawing equal volumes of ts136 cell culture and pulse-labelling with [35S]methionine at various time intervals after the shift to 37 degrees C from 23 degrees C. The synthesized proteins were separated on a two-dimensional gel electrophoretic system and then quantitatively analyzed for theri incorporated radioactivities by scintillation counting. Our results show that yeast mRNAs have divergent functional half-lives ranging from 4.5 to 41 min, with an average value of 22 min. Each mRNA exhibits a simple exponential decay with its own characteristic dacay pattern. Of the approximately 500 major polypeptides made by yeast cells, which are detectable on autoradiograms of the gels, 80 were arbitrarily selected and the mRNAs coding for those polypeptides were examined for their decay kinetics. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A streptomycin-resistant Escherichia coli mutant with ribosomes temperature-sensitive in the suppression of a nonsense codon.? [/INST] Cell free extracts from a streptomycin-resistant E. coli mutant which is also temperature-sensitive for Q beta phage were studied for suppression of a nonsense mutation at various temperatures. The streptomycin-resistant ribosomes of the mutant were found to be temperature-sensitive in suppression of an amber mutation in f2 phage coat protein while retaining the ability to synthesize proteins at an elevated temperature (42 degrees C). The restriction of amber suppression at 42 degrees C is assumed to be related to an alteration in ribosomal protein S12 of the streptomycin-resistant mutant which also causes a change in its electrophoretic mobility. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The requirement of nonsense suppression for the development of several phages.? [/INST] A spontaneous streptomycin-resistant Escherichia coli mutant which is temperature-sensitive for suppression of a nonsense codon was studied for its ability to propagate phages T2, T4D, T5, phi K, f2, MS2, R17, Q beta, lambda as well as filamentous phages fl, fd and M13. Of all phages tested, only the growth of Q beta, lambda, and filamentous phages is inhibited in the mutant at 42 degree C. This selective inhibition suggests that, like Q beta, lambda and filamentous phages also require a read-through proten(s) which results from suppression of a termination codon. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Methylgroups of ribosomal protein L11 are not related to the synthesis of ppGpp.? [/INST] Ribosomes carrying either a normally methylated or an undermethylated L11, respectively, were tested with respect to the stringency reaction in the presence of crude stringent factor. Systems with either kind of ribosomes synthesize ppGpp with the same efficiency. The ppGpp synthesis in presence of ribosomes with undermethylated L11 depends also on stringent factor, mRNA and deacylated tRNA whereas aminoacyl-tRNA and peptidyl-analogous tRNA show no effect. Thus, the absence of methylation in L11 does not influence the stringency reaction. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Induced segregation in interspecific hybrids of Aspergillus nidulans and Aspergillus rugulosus obtained by protoplast fusion.? [/INST] Interspecific hybrids produced by polyethylene glycol induced fusion of protoplasts from auxotrophic mutants of Aspergillus nidulans and Aspergillus rugulosus were grown in the presence of the recombinogens benomyl and chloral hydrate to stimulate segregation. The A. nidulans parental strains used had a known genetic marker in each linkage group. Hybrids grown on complete medium containing benomyl yielded more segregants. Analysis of the segregants showed that the distribution of A. nidulans linkage groups was random. No specific linkage group appeared in all the segregants. The two parents are closely related taxonomically and the findings from these experiments suggest that a high degree of chromosomal homology may exist between them. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Peptide chain elongation rate and ribosomal activity in Saccharomyces cerevisiae as a function of the growth rate.? [/INST] The peptide-chain elongation rate of Saccharomyces cerevisiae at two different growth rates was estimated by the kinetics of radioactive labelling of nascent and finished polypeptides as described by Gausing, 1972, and Young and Bremer, 1976. The elongation rates of a diploid strain cultured in yeast nitrogen base supplemented with glucose or acetate were 9.3 amino acids/s and 5.5 amino acids/s at 30 degrees C, respectively. These data together with published values on the "ribosomal efficency" as a function of growth rate (Waldron and Lacroute, (1975) enable us to estimate the rate of synthesis of ribosomal proteins as a function of the rate of total protein synthesis, alpha r, and the fraction of ribosomes that one active in protein synthesis. We conclude that in S. cerevisiae alpha r is largely independent of the growth rate while the fraction of active ribosomes decreases with decreasing growth rate. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Cloning of an EcoRI fragment carrying E. coli tufA gene.? [/INST] EcoRI fragments of the transducing phage lambda fus3 DNA have been linked to the ColEl derivative plasmid RSF2124 (ColEl-Apr) DNA using bacteriophage T4 ligase. Among the plasmids formed, one designated pTUAl was found to contain the E. coli tufA gene. The proof for the presence of tufA gene in pTUAl is based on the following observations: (1) ability of pTUAl DNA and is EcoRI fragments to direct synthesis of EF-Tu in a cell-free protein synthesizing system; and (2) RNA . DNA hybridization of RNA transcribed from phage lambda rifd18 carrying tufB with DNA from pTUAl. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The art and science of clinical teaching.? [/INST] A review of the literature on clinical teaching indicates that medical schools emphasize didactic teaching of facts. Interpersonal skills, problem solving skills and cultivation of attitudes are neglected. However, the literature also described the skills of 'good' clinical teachers, and enumerates them. Programmes attempting to develop students' interpersonal skills and problem solving skills are reported. Finally, areas for further practice and study in clinical teaching are recommended. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Tinidazole in the prevention of wound infection after elective colorectal surgery.? [/INST] During the first six months of 1978, 71 patients were the subject of a controlled trial of the use of tinidazole for the prevention of wound infection after elective colonic surgery. The trial design was prospective, randomized and double-blind with tinidazole or placebo given at the last oral intake before operation. The objective endpoint of the trial was the presence or absence of wound infection manifested by pus. All patients underwent a standard preoperative preparation of bowel washouts, and a standardized surgical technique included, in all cases, the use of wound drainage. At the end of the trial there were three wound infections in 40 patients who were given tinidazole, and eleven wound infections in 31 patients who were given placebo. The difference in wound infection rate between these two groups is significant (x2 with Yates correction = 7.3; P less than 0.01). </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mineral springs and spring fever. Lithium: fact and fantasy in psychopharmacology.? [/INST] Lithium salts have been employed as medical treatment for more than two thousand years. The history of lithium in medicine reveals a strictly empiricist approach to its use which has resulted in its varying popularity as a therapeutic treatment over the past century. Much of the enthusiasm about the therapeutic use of lithium has been generated by faulty scientific process. This paper reviews the scientific errors which have surrounded the medical use of lithium in history, discusses the metaphorical use of medical terminology and the problem which is posed by the literal interpretation of such terms, and challenges the currently accepted point of view that lithium is a specific treatment for mania. The scientific errors which have resulted in the introduction of lithium as a treatment for mania are reviewed, and it is proposed that lithium treatment be viewed as the paradigm of modern psychopharmacology. The author suggests that the empiricist approach in biological psychiatry requires critical scrutiny in order to avoid tragic consequences, regarding the hazards both to patients arbittrarily exposed to lithium therapy, as well as to the scientific concept of disease as it is modified by those who wish to re-define disease, empirically, in terms of response to treatment. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mason-Pfizer like virus in kidney grafted patients.? [/INST] Lymphocytes from a kidney grafted patient were specifically stimulated to incorporated thymidine in vitro by mitomycin C treated Hela cells infected with a Mason-Pfizer like virus (MPV). The thermolabile mutant of vesicular stomatitis virus (VSV tl) grown in leukocytes of this patient produced pseudotypes which were neutralized by the patient's sera and boy rabbit anti-MPV sera. Coculture of the patients leukocytes with SIRC cells yielded virus populations with dual properties; those of MPV plus those of another virus which was not typed serologically but possessed the biological properties of typical C particles. The patient also had neutralizing antibodies to MPV, which were detected by inhibition of syncytium formation on KC cells and by neutralization of VSV tl (MPV) pseudotypes. Preliminary results on the frequency of similar findings in other kidney grafted patients are presented. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The relation of repair phenomena to mutation induction in bacteria.? [/INST] The relation of various processes to mutation induction by radiation and chemicals is discussed for for various species of bacteria. A variety of repair processes have been identified at the molecular level that can eliminate many kinds of potentially mutagenic lesions before they can be converted to final mutation. Fixation often but not always occurs at replication. A number of mutagens, including UV light, ionizing radiation, and a number of chemicals, induce an error-prone process, perhaps a modification of the proof-reading system, that allows bacteria to survive after potentially lethal damage at the expense of making errors. Some mutagens, notably monofunctional alkylating agents and base analogues, produce mutations by other processes. Even in these cases, repair processes play an important role. There is some evidence that error-free as well as error-prone repair processes can be induced. A brief discussion is given of the relation of these findings to the practical problems of hazards estimations. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Photodynamic effects of dyes on bacteria. II. Genetic effects of broad-spectrum visible light in the presence of acridine dyes and methylene blue in chemostat cultures of Escherichia coli.? [/INST] Photodynamic mutagenesis was studied in chemostat cultures of Escherichia coli B/r (TlR trp) exposed to one of six different acridine dyes or methylene blue. Mutation to phage T5 resistance was induced with a broad-spectrum fluorescent-light source. All of the agents tested were photomutagenic; acridine yellow was the most efficient sensitizer and quinacrine was the least efficient. Quinacrine also was moderately mutagenic in the dark, in contrast to the other agents tested, which were not significantly mutagenic in the dark at the low concentrations tested for photomutagenesis. The mutation rate with acridine orange was directly proportional to both fluence rate and dye concentration over the ranges tested. Photomutation rates with acridine orange, proflavine and methylene blue were independent of growth rate of the chemostat cultures. These results are consistent with photomutagenesis occurring as the result of photochemical damage to DNA-dye complexes, independent of cell expression was approximately 2.5 generations for each of the photomutagens tested. This short expression delay supports an earlier segregational model for expression of phage resistance. The following results suggest that photodynamic mutagenesis is due mainly to intercalated dye molecules: (1) both acridine and 9-aminoacridine are photodynamic mutagens; (2) acridine inhibits photomutagenesis with acridine orange; and (3) neither putrescine or spermine, which bind to DNA without intercalating, inhibited photomutagenesis by acridine orange or proflavine. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of mutagens, chemotherapeutic agents and defects in DNA repair genes on recombination in F' partial diploid Escherichia coli.? [/INST] The ability of mutagenic agents, nonmutagenic substances and defects in DNA repair to alter the genotype of F' partial diploid (F30) Escherichia coli was determined. The frequency of auxotrophic mutants and histidine requiring (His-) haploid colonies was increased by mutagen treatment but Hfr colonies were not detected in F30 E. coli even with specific selection techniques. Genotype changes due to nonreciprocal recombination were determined by measuring the frequency of His- homogenotes, eg. F' hisC780, hisI+/hisC780, hisI+, arising from a His+ heterogenote, F' hisC780 hisI+/hisC+, his1903. At least 75% of the recombinants were homozygous for histidine alleles which were present on the F' plasmid (exogenote) of the parental hetergenote rather than for histidine alleles on the chromosome. Mutagens, chemotherapeutic agents which histidine alleles on the chromosome. Mutagens, chemotherapeutic agents which block DNA synthesis and a defective DNA polymerase I gene, polA1, were found to increase the frequency of nonreciprocal recombination. A defect in the ability to excise thymine dimers, uvrC34, did not increase spontaneous nonreciprocal recombination. However, UV irradiation but not methyl methanesulfonate (MMS) induced greater recombination in this excision-repair defective mutant than in DNA-repair-proficient strains. Mutagenic agents, with the exception of ethyl methanesulfonate (EMS), induced greater increases in recombination than the chemotherapeutic agents or the polA1 mutation. EMS, which causes relatively little degradation of DNA, was more mutagenic but less recombinogenic than MMS, a homologous compound ths that inhibition of DNA occurring single-stranded regions in replicative intermediates of the DNA. Mutagens which cause the rapid breakdown of DNA may, in addition, introduce lesions into the genome that increase the number of single-stranded regions thus inducing even higher frequencies of recombination. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Validation and characterization of the L5178Y/TK+/- mouse lymphoma mutagen assay system.? [/INST] The current status of the L5178Y/TK+/- leads to TK-/- mouse-lymphoma mutagenicity assay is described. Dose-survival-mutagenic response data are shown for 43 chemicals. Mutagenicity and cytotoxicity in the presence or absence of non-induced and/or Aroclor-induced rat-liver S-9 are compared for most of these chemicals, 25 of these for which usuable carcinogenicity data exist have been used to construct an approximately linear relationship between oncogenic potency in vivo and mutagenic potency in this system in vitro; linearity between these two endpoints extends over a greater than 100,000-fold range in potencies. Several carcinogens which are negative or difficult to detect in the standard Ames assay are mutagenic in this mammalian cell system. These include natulan, sodium saccharin (lot S-1022), p,p'-DDE (metabolite of DDT), dimethylnitrosamine, diethylnitrosamine and diethylstilbestrol. Characterization of the TK-/- mutants suggests that two mutagenic mechanisms contribute to their final yield. Large-colony TK-/- mutants probably represent point or gene mutations affecting the TK locus. In addition, a class of small-colony TK(/- mutants are described and characterized as being heritably growth-deficient; this and other properties suggest that these small-colony TK-/- mutants originate by a heritable and viable chromosomal aberration. Most carcinogens and mutagens tested produce both classes of TK-/- mutants in this system; the relative proportions of small- and large-colony mutants are both mutagen- and dose-dependent. Comparative studies have been done at the rapidly-expressing TK locus and the slowly-expressing HGPRT locus in these cells. Several carcinogens detected at the TK locus are non- or very weakly mutagenic at the HGPRT locus. This findings is consistent with the induction of slow-growing specific locus mutants by a chromosomal mechanism and their subsequent dilution during this long expression time. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Photodynamic effects of dyes on bacteria. III. Mutagenesis by acridine orange and 500-nm monochromatic light in strains of Escherichia coli that differ in repair capability.? [/INST] In the presence of acridine orange (AO) and monochromatic 500-nm light, the recombination-deficient strain of Escherichia coli, WP10 (recA), showed a 15-fold increase in mutation rate over the wild-type (WP2) strain. Under the same conditions, strain Bs--1 (uvrB lexA lon) showed a 5-fold increase in mutation rate over strain WP2. In contrast, the endonuclease-deficient, strain, WP2s (uvrA), showed a lower AO-500 nm mutation rate than wild-type. The extremely high mutation rate of the recA strain cannot be due to error-prone inducible SOS repair since the inducible recA + function is absent. Repair of the AO-500 nm-induced lesions is likely due to a recA+-dependent, error-free, recombination process. It is concluded that the high mutation rates with AO-500 nm light obtained in chemostat cultures of recA and lexA strains occur as a consequence of errors during semi-conservative DNA replication in the presence of unrepaired DNA lesions. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mutation induction by thymidine deprivation in Escherichia coli B/r. I. Influence of caffeine.? [/INST] The addition of caffeine to the plating medium after thymine deprivation of E. coli WP2 uvr+ thyA or WP2 uvrA thyA had no influence on survival. Caffeine, however, reduced the frequency of mutants. The hypothesis is presented that the reduced mutagenesis is due to the sensitivity to caffeine of an inducible error-prone repair mechanism operating during thymine deprivation and after the re-addition of thymine. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Aryl-monoalkyl and cyclic triazenes: direct-acting mutagens.? [/INST] An aryl-monoalkyl triazene, methyl-p-tolyl triazene (MTT) and a cyclic triazene (delta2-triazoline) are direct-acting mutagens for Salmonella typhimurium bacteria and for cell-free Hemophilus influenzae DNA. MTT causes reversion of the hisG46 base-substitution mutation, but no reversion of the hisD3052 frameshift mutation. Induced mutation frequency is not strongly influenced by modifications in the genetic background of the S. typhimurium Ames tester strains, but is mildly enhanced by the addition of a pool of amino acids to the plating medium and is strongly enhanced by liquid preincubation before plating. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of gamma and alpha irradiation on survival of wild-type and sensitive mutants of yeast.? [/INST] Survival curves have been obtained for haploid and diploid Saccharomyces cerevisiae of the wild-type strain and the sensitive mutant rad51-1 exposed to gamma-rays and alpha-particles. The difference in radio-sensitivities of the wild-type diploid strain and the homozygous rad51-1 mutant was significantly higher after low-LET radiation than after high-LET radiation. This was not true for haploid strains. The liquid-holding recovery of irradiated cells was greater for gamma-ray-induced damage than for damage inflicted by alpha-particles. The value of the RBE of high-LET radiation was correlated with cell-repair capacity. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Further study of the genetic toxicity of gentian violet.? [/INST] The genetic toxicity of gentian violet was studied with the Ames and the Rosenkranz bacterial assays as well as the cytogenetic assays (Chinese hamster ovary cells in vitro in the presence of rat-liver S-9 fractions, the chicken-embryo and mouse-bone-marrow cells in vivo). Gentian violet was found to be toxic but not mutagenic in the Ames assay. However, it was active in the Rosenkranz assay causing reparable DNA damage. The presence of S-9 in the in vitro cytogenetic assay and in the bacterial assays showed that the activity of gentian violet could be reduced or eliminated. In the in vivo assays, gentian violet was not clastogenic and failed to induce sister-chromatid exchanges. However, gentian violet proved to be highly toxic to growing chick embryos at high dosage and depressed mitotic activities in mouse bone marrow after prolonged treatment. Our study suggested that gentian violet can be inactivated by the liver detoxification system. However, it is potentially hazardous to cells that are exposed to the dye directly (e.g. skin epithelium and cell lining of the gastrointestinal tract). </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Actions of an antispermatogenic, but non-mutagenic, indenopyridine derivative in mice and Salmonella typhimurium.? [/INST] This paper describes a new antispermatogenic agent. Following single oral administration to mice, the indenopyridine derivative (4aRS,5SR,9bRS)-2-ethyl-1,3,4,4a,5,9b-hexahydro-7-methyl-5-p-tolyl-2H-indeno(1,2-c)pyridine hydrochloride, code No. 20-438, produced long-lasting inhibition of the spermatogenic process at dose levels of 10 mg/kg (1/40 of the lowest lethal dose) and higher. Testes weights were significantly reduced from days 2--217 after treatment, and no clear-cut evidence of a recovery was found during this time. The fertility of treated males was normal during the initial 2 weeks after treatment, followed by partial or total sterility in weeks 3--6, and incomplete recovery in weeks 7--29 after treatment. The antifertility effects were caused by maturation depletion of the germ cells, leading to oligospermia. The following rank of decreasing "susceptibility" of the germ cells was observed: Spermatocytes greater than early spermatids, intermediate spermatogonia greater than stem cells. Sperm and late spermatids were not affected. Despite the characteristic specific germ-cell pattern of antifertility effects, 20-438 showed neither indications of pre- and post-implantational dominant lethality, nor mutagenic potentiality as measured by cytogenetic analysis of spermatocytes or spermatogonia, the sperm abnormality assay, the micronucleus test, and the Salmonella assay. These data suggest that the action of 20-438, leading to oligospermia, does not involve genetic toxic effects. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Lack of cytogenetic effects in mice or mutations in Salmonella receiving sodium fluoride.? [/INST] We have examined the possible effect of fluoride intake on chromosome damage. There was no evidence of increased frequency of chromosomal aberration in bone marrow or testis cells of mice with either 50 ppm fluoride intake over several generations or 100 ppm intake for 6 weeks compared to animals drinking distilled water. Fluoride was not found to be mutagenic in a widely used bacterial mutagenesis assay over a range of 0.1 to as high as 2000 microgram fluoride per plate. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Skeletal concentrations of lead in ancient Peruvians.? [/INST] The level of biologic lead (expressed as the ratio of atomic lead to atomic calcium) in bones of Peruvians buried 1600 years ago was found to be 3 x 10(-8), as compared to 2100 to 3500 x 10(-8) in the bones of present-day residents of England and the United States. The ratio of barium to calcium was 2 to 3 x 10(-6) in bones of ancient Peruvians and present-day Americans. Barium and lead have similar morphologic distributions in organisms, so this discrepancy for lead must result from overexposure of present-day people to industrial lead and not from natural variations. The magnitude of this discrepancy has been confirmed by two different lines of investigation not reported in this article. This new evidence suggests that natural interactions of lead in human cells have not yet been determined because reagents, nutrients and controls used in laboratory and field studies have been contaminated with lead far in excess of naturally occurring levels. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Transmission of allosteric effects in DNA.? [/INST] Binding of distamycin induces a cooperative transition of calf thymus DNA to a new form with higher affinity for the drug and altered structural properties. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Distribution of polymorphic forms of troponin components and tropomyosin in skeletal muscle.? [/INST] Specific antibodies have been used to show that in adult skeletal muscle the slow and fast forms of the components of the troponin complex are located in type I and type II fibres respectively. alpha-Tropomyosin is restricted to type II cells. During development, as a result of changes in innervation and in certain diseased stages, both the slow and fast polymorphic forms of the troponin components are present in the same cell. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Luteinizing hormone-releasing hormone (LH-RH) neurons in cultures of fetal rat hypothalamus.? [/INST] Hypothalamic fragments from 21-day-old fetal rats were cultured in Maximow double-coverslip assemblies for 1 to 2 months. Neurons containing LH-RH were demonstrated immunohistochemically using an antiserum to LH-RH (Dermody; 1:500--1:4,000). LH-RH was demonstrable only in neuronal perikarya (8--13 micrometer) and in small (less than 1 micrometer) round structures nearby, primarily in explants of the median eminence-arcuate nucleus region. Reactive neurons were not found in explants of the preoptic area and could not be demonstrated in fetal hypothalami at the time of explantation. The presence of mature-looking LH-RH containing neurons in these cultures suggests that this tissue culture system can be used for the study of hypothalamic development. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The profile and severity of lithium-induced side effects in mentally healthy subjects.? [/INST] In a double-blind, placebo-controlled, crossover design various side effects (= unwanted effects) during 6 months of therapeutic serum lithium levels (0.7-1.1 mmol/1) to nonpsychiatric patients were studied. The side effects were measured by self-rating scales and independent observer rating scales administered every 2-4 weeks throughout the study. After months of treatment, lithium induced hand tremor and thirst/polyuria; however, without any relationship to the serum levels of lithium. The frequency of tremor was highest in patients above the age of 60 years. No initial sedative-like lithium effect was found. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Creutzfeldt-Jakob disease: familial clustering among Libyan-born Israelis.? [/INST] Creutzfeldt-Jakob disease was studied among Libyan-born Israelis, in whom the disease appears with unusual frequency. Interviews with relatives of deceased victims revealed statistically significant clustering within families. The results suggest either a common source of exposure or a genetic influence on susceptibility to the virus. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Creutzfeldt-Jakob disease--alteration in ganglioside sphingosine in the brain of a patient.? [/INST] Gangliosides isolated from the brain of patients with Creutzfelt-Jakob (C-J) disease were analyzed. The ganglioside current was abnormally low, and the percentage distributions of individual gangliosides and the long-chain base compositions were abnormal. The C20-sphingosine contents of all the ganglioside fractions were low. Abnormalities in ganglioside long-chain bases in adult human brain have been reported previously only in patients with inherited metabolic disorders. These abnormalities in C-J disease seem to be closely related to the cause of the disease. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Thrombocytopenia in obstetric syndromes. A review.? [/INST] Thrombocytopenia is a phenomenon sometimes observed in connection with various obstetric syndromes. Many times it appears clinically to be a comparatively benign complication of an otherwise significant disease. In some cases, however, it may be a clue to serious disease and its pathophysiology. The subject of thrombocytopenia induced by or related to various obstetric syndromes is reviewed and comments offered regarding the significance of the observation of platelet deficiency in these conditions. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Contemporary management and conduct of preterm labor and delivery: a review.? [/INST] Current concepts in the conduct of preterm labor and management of delivery of the premature infant are reviewed. Pharmacologic modalities available for inhibiting preterm labor are discussed as well as the efficacy, indications and contraindications for these agents. An analysis of the role of corticosteroids in achieving fetal pulmonary maturity in the preterm infant is reviewed, and based on the existent literature the intrapartum management of the small fetus is outlined. The mode of delivery, vaginal or via cesarean section, for these infants is likewise discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The role of C. albicans in denture stomatitis.? [/INST] Denture stomatitis is an erythematous disorder of the denture-bearing tissues, especially the maxillary hard palate. Frequently it mimics many oral lesions. Early diagnosis of the lesion is essential to assure rational therapy. A diagnostic procedure based upon the enumeration of Candida albicans appeared to be feasible. A control group of twenty fully dentate subjects with no clinical evidence of stomatitis was sampled to establish normal concentrations of C. albicans in the oral flora. Samples were taken from a triangular area of the hard palate, serially diluted in broth, and all dilutions were incubated aerobically. In the control population, C. albicans never exceeded 100 organisms per square centimeter per subject sample. A population of edentulous patients with denture stomatitis, prior to any therapy, was similarly sampled. In many of these patients the concentration of C. albicans always exceeded 10,000 organisms per square centimeter per patient. The patients received denture replacements and antimycotic antibiotic therapy. Follow-up cultures were taken 4 to 6 weeks after completion of therapy. All patients were found to be free of denture stomatitis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effects of etching enamel with acid on human dental pulp. A preliminary study.? [/INST] Enamel acid-etching has become a widespread, popular clinical procedure in recent years. Numerous studies have investigated the nature of the acid-treated enamel. However, little or no information is presently available pertaining to the effects of acid treatment upon dental pulp tissue. A limited investigation was carried out on bilateral orthodontic extraction cases to determine the effects of enamel acid-etching upon healthy dental pulp. In each of five cases one premolar served as the experimental tooth, while the contralateral premolar served as the control. After a 24-hour postoperative interval there appeared to be no basic histologic difference between the experimental and control groups. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The identification of soluble adult antigen on the tegumental surface of juvenile Fasciola hepatica.? [/INST] An antiserum was raised in rabbits against a soluble extract of fresh homogenized adult Fasciola hepatica of rat origin and was then absorbed with rat and mouse tissue antigens. This antiserum reacted specifically with the surface coat of adult flukes, of both rat and mouse origin, by indirect immunofluorescence to show the detail of surface spines. When tested against juvenile stages recovered from mice the reaction was positive with all but the earliest hepatic parenchyma stages. No reaction was present on the tegumental surface of newly excysted juveniles or stages 1 or 2 days post-infection (p.i.) whether recovered from the peritoneal cavity or the hepatic parenchyma. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The ribosomes of Plasmodium berghei: isolation and ribosomal ribonucleic acid analysis.? [/INST] Ribosomes and high molecular weight ribosomal ribonucleic acid (rRNA) from the blood stages of Plasmodium berghei parasites were studied in preparations free from host ribosome contamination. Purified malarial ribosomes were isolated in high yield from a population of ultrastructurally intact, viable parasites by hypertonic lysis with Triton X-100 and differential centrifugation. These ribosomes were shown to be derived from active polysomes and could be dissociated into subunits by puromycin-0.5 M KCl treatment. Malarial rRNA extracted from purified 40S and 60S ribosomal subunits was characterized by electrophoretic, sedimentation and base ratio analyses. Like certain other protozoa, the P. berghei 40S ribosomal subunit possessed an exceptionally large RNA species (mol. wt 0.9 X 10(6), while RNA isolated from the parasite's 60S subunit (mol. wt 1.5 X 10(6)) was specifically 'nicked' to produce one large component (mol.wt 1.2 X 10(6)) and one small component (mol.wt 0.3 X 10(6)) in equimolar quantities. These rRNA's migrate identically on polyacrylamide gels after heating to 63 degrees C for 5 min or under denaturing conditions in the presence of formamide, indicating an absence of aggregation and non-specific degradation of the rRNA species. Base composition studies showed P. berghei rRNA to be low in guanosine and cytosine content, as is the case for protozoa generally. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Retinoblastoma.? [/INST] Retinoblastoma is a radiosensitive malignancy of neuroblastic origin that primarily affects young children. Its relatively low incidence belies its potential importance in the understanding of tumor biology in general. A case is made for referral of all retinoblastoma patients to centers with retinoblastoma protocols. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Right aortic arch with aberrant left innominate artery.? [/INST] A 9-year-old girl with type D right aortic arch anomaly, has been presented. The diagnosis was based upon the presence of signs and symptoms of a vascular ring and the early visualization of a retroesophageal aberrant left innominate artery, by means of countercurrent right brachial angiography. Division of the ligamentum arteriosum at operation relieved the symptoms. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effects of endotracheal tube leaks on functional residual capacity determination in intubated neonates.? [/INST] The present study evaluates a new closed circuit helium (He) dilution technique for determination of endotracheal (ET) tube leakage and functional residual capacity (FRC) in neonates with ET tubes. By analytically relating the fall in He concentration due to mixing with that due to leakage, it is possible to predict the final equilibration concentration of He and, therefore, correct for ET tube leaks. The system (120 ml) contains an air pump, He meter, breathing bag in cyclinder, a strip chart readout, and solenoid valve. Continuous positive airway pressure (CPAP) or ventilator pressure can be applied during testing. FRC measurements were performed on 13 neonates (799--4500 g) on CPAP with ET tubes. Leak rates were significantly higher (P less than 0.001) on 3 cm H2O CPAP compared to O cm H2O CPAP. The mean measured FRC was 53.5 ml at 3 cm H2O and 46.3 ml at 0 cm H2O CPAP. If gas leakage had not been considered in FRC calculations, the error in FRC could have been as high as 39% at 3 cm H2O CPAP and 18% at 0 cm H2O CPAP. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Inhibition by indomethacin of the renal response to an acute saline load in the dog.? [/INST] The kidneys of sodium-loaded dogs, treated by indomethacin before their transplantation to the neck vessels of sodium-depleted animals, lose their ability to increase the fractional excretion of sodium following an intravenous infusion of saline; they behave similarly to the kidneys of sodium-depleted dogs. Moreover, they become unable to potentiate the response of the kidneys of the sodium-depleted perfusors. The experimental conditions exclude a direct effect of the drug eo ipso. The results indicate that renal prostaglandins are involved in the adjustment of the renal response to saline loading, depending on the previous dietary sodium balance, and that they are related with the potentiating factors released into the blood by the kidneys of sodium-loaded animals. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Influence of calcium and ionophore 23187 on tubular phosphate reabsorption.? [/INST] In previous studies it has been demonstrated that a decline of plasma calcium concentration accounts for the decrease of phosphate reabsorption in thyroparathyroidectomized (TPTX) rats undergoing phosphate loading. Microinfusion studies were performed in TPTX rats in order to discriminate between a systemic effect of calcium an a direct renal effect. Thyroparathyroidectomized animals were infused with a phosphate solution continuously. When plasma calcium concentration fell below 1.30 mmol/l, proximal convoluted tubules were microinfused with a phosphate tracer solution for 42 min. After 18 min a calcium chloride-containing solution was applied superficially (superfused) to the area of the microinfused tubule. This elevation of peritubular calcium concentration led to an immediate increase of phosphate reabsorption up to 12% of the microinfused phosphate load within 24 min. In another series of experiments, the calcium specific ionophore A23187--a substance which is known to increase intracellular calcium--was superfused on the microinfused tubule. This resulted again in an increase of fractional phosphate reabsorption of about 15% after 24 min. In contrast, when calcium chloride-free as well as ionophore-free solutions were superfused fractional phosphate reabsorption decreased (7%). From these data we conclude that 1. calcium has a direct renal effect on phosphate reabsorption in the absence of parathyroid hormone and 2. intracellular calcium appears to be a major parameter in the regulation of renal phosphate transport under these conditions. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A fiberoptic reflection densitometer with cardiac output calculator.? [/INST] A catheter-tip densitometer for indocyanine green is described consisting of a cardiac catheter containing optical fibers, an incandescent light source, a light detection unit and a processing unit. Half of the optical fibers guide the light to the blood at the tip of the catheter, the other half the back-scattered (reflected) light to the detection unit. In the detection unit the light is measured by two silicium barrier layer photocells after it has been split into two beams by a beam splitter. In the measuring channel the light passes an 800 nm filter before reaching the photocell. When fiberoptic catheters with glass fibers are employed, the other channel, used for compensation of non-specific effects such as blood flow variations, contains no filter, thus measuring light in a broad spectral band. It is shown that in this way compensation of flow effects may be about two times better than when a 920 nm filter is used. When using plastic optical fibers a 950 nm filter must be used, because above lambda = 850 nm plastic fibers transmit only a band around that wavelength (950 nm). At zero dye concentration the densitometer output or ratio of compensating and measuring photocell output R/R800 is almost insensitive to changes in haemoglobin concentration. When the blood contains dye, however, the influence of haemoglobin concentration is considerable. The densitometer output R/R800 is linearly related to dye concentration up to 50 mg . 1-1, the output R920/R800 up to 30 mg . 1(-1). The output R/R800 decreases with decreasing oxygen saturation; the slope of the calibration line, however, appears to be unaffected. The processing unit also contains an analog cardiac output calculator consisting of an integrator and a divider. Central dye dilution curves recorded from the pulmonary artery after injection of dye into the right atrium or a caval vein come down to the baseline. At this moment the reading of a digital voltmeter displaying the divider output calibrated in 1 . min-1 can be held and the reading taken. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The unprejudiced basis of bias.? [/INST] The results of a study can be invalid if the study population is not chosen properly. Four hypothetical examples show how unintentional selection bias can occur and how to recognize it in both prospectiveand retrospective studies. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A model for the cardiac-associated changes of the thoracic electrical impedance in man.? [/INST] A simple mathematical model has been developed which is able to fit the impedance waveform produced by normal and abnormal subjects throughout the cardiac cycle with reasonable precision. Contributions from both the aorta and vena cava are significant. Fitted values of model parameters offer potentially useful clinical information. Estimates of the stroke volume obtained from the model correlate will with values derived from the maximum rate of change of the thoracic impedance during systole, but are in poorer agreement with values obtained using tracer dilution techniques. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effects of reserpine on microcirculatory flow in rat flaps.? [/INST] A model flap was developed in the rat which allowed us to quantitate microcirculatory blood flow within a flap, and to correlate the flow with the length of flap eventually surviving. A critical flow of 0.02 and 0.03 ml/min/gm (measured during the first 24 hours after flap elevation by radioactive microspheres) appears to be necessary for tissue survival. Reserpine, in a dose of 5 mg/kg, did not increase blood flow in the flap or the length of flap surviving in this model. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Justinian II and Carmagnola: a Byzantine rhinoplasty?? [/INST] The Carmagnola statue, although undoubtedly a Byzantine Emperor, still holds its secret as to who it actually represents, and how his nose got that way. Our tentative conclusions concerning the possibility of Justinian's Indian nasal reconstruction only raise other questions. If Justinian Rhinometos did have a nasal reconstruction, how was the knowledge of the technique transmitted from northern India to the Byzantine Empire by the end of the 7th century? And if Justinian did have his "rhinokopia" surgically corrected, would this represent the first case of nasal reconstruction in the western world, 900 years before the triumphs of Tagliacozzi? </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Uses of the trapezius and sternomastoid myocutaneous flaps in head and neck reconstruction.? [/INST] Both of these myocutaneous flaps can supplant forehead and deltopectoral flaps, in certain indications. They are additional arterialized flaps for the armamentarium of the reconstructive surgeon, and can be useful in many repairs in the head and neck region. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The pectoralis major myocutaneous flap. A versatile flap for reconstruction in the head and neck.? [/INST] A compound flap is described that utilizes skin from the anterior chest on a narrow segment of pectoralis major muscle, with its underlying axial neurovascular bundle. This flap has been used successfully to reconstruct large defects in 4 consecutive patients. Our experience with this flap suggests that it may be more versatile than the deltopectoral flap. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Experimental work with isoxuprine for prevention of skin flap necrosis and for treatment of the failing flap.? [/INST] The administration of isoxuprine intraperitoneally resulted in the complete survival of abdominal island skin flaps in rats that otherwise underwent a standard pattern of necrosis. The drug was effective when administered for two weeks before and one week after raising the flap, or when administered afterwards alone. The mechanisms of its action were investigated and are described. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Free toe-to-fingertip neurovascular flaps.? [/INST] Six cases of free toe-to-fingertip neurovascular flaps are presented. The principal advantages of this procedure over rotation island flaps are (1) achievement of better two-point discrimination, (2) an acceptable donor defect, (3) no cortical reorientation is necessary, and (4) there is minimal tension on the nerve. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about One-stage reconstruction for defects of the mouth using a sternomastoid myocutaneous flap.? [/INST] The sternomastoid muscle has 3 blood supplies: the occipital artery superiorly, the superior thyroid artery in the middle, and the thyrocervical trunk below. We report the use of a myocutaneous flap consisting of a "paddle" of skin on the end of a pedicle of sternomastoid muscle--with the latter based either on its superior or inferior blood supply. Fourteen such flaps have been used successfully in 13 consecutive patients for one-stage reconstructions of defects of the oral cavity and oropharynx. Although there was partial epithelial loss of the skin "paddle" in 7 cases, in each case the surviving dermis became resurfaced with epithelium. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The locking loop tendon suture.? [/INST] The locking loop tendon suture is suggested as an effective method for suturing tendons where tension is likely during the early post-operative period. The relationship of the intratendinous parts of the suture to each other is critical to the resultant tensile strength. Experimental work has confirmed its strength and its lack of interference with the intrinsic vasculature of the tendons. Our results from this clinical repair of 72 tendons by this method have been better, in general, than we obtained with other currently popular methods. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Latissimus dorsi myocutaneous flaps in head and neck reconstruction.? [/INST] We have found the latissimus dorsi myocutaneous flap, when used as a "pedicled island flap," to be an adaptable and dependable alternative flap for repairs after major resections in the head and neck. The long vascular pedicle, containing large vessels, provides a means to transfer a large bulk of tissue into the head and neck for the repair of major through-and-through defects. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Angiography of the iliofemoral arteriovenous system supplying free groin flaps and free hypogastric flaps.? [/INST] The circulatory anatomy of the iliofemoral region was elucidated by doing detailed angiography in 50 cases, and we classified the vessels into 4 types. In most cases, the s.c.i.a. predominated over the s.i.e.a. Therefore, it is probably better to plan free flaps supplied by this artery. This vessel usually arises approximately two or three fingerbreadths inferior to the intersection of the femoral artery and the inguinal ligament, and the skin flap should be designed in the area inferior and parallel to the inguinal ligament. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Evaluation of anastomotic techniques in the experimental transfer of free skin flaps.? [/INST] Vascularized groin flaps were transferred to the contralateral side by various microvascular anastomotic techniques. There was no statistical difference between the results of end-to-end and end-to-side anastomoses, when the same sized vessels were compared. However, significant differences existed when vessels smaller than 0.5 mm in diameter were anastomosed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Case report: Reconstruction of the mid-face in an adult, after gangrenous destruction in infancy.? [/INST] We report a case of an adult mid-face reconstruction for a deformity occurring in infancy, using a Le Fort III advancement first to restore the contour of the skeleton. This was followed by a scalping forehead flap for the nasal reconstruction, and a fleur-de-lis Abbe flap for reconstruction of the lip and nasal vestibule. </s>