bluuebunny/crossref_metadata_2025 huggingface dataset:
DIRECT TESTING OF ANTIBIOTIC SENSITIVITY BY A MICROCOLONY METHOD
Authors: Chadwick P. , Mahony D. E.
Published: February 2010

A microcolony method of measuring antibiotic sensitivity requiring 4 hours incubation, was adapted to testing of organisms obtained directly from swabs, urines, and blood cultures. The results of the "direct" 4-hour test were compared with those obtained by prolonging incubation to 20 hours and with results obtained by carrying Out similar tests on the individual organisms isolated in pure culture ("indirect" tests). All of 12 urine samples and 6 infected blood specimens proved suitable for testing but only 35 of 68 swabs were suitable. Unequivocal results in direct tests were obtained in 94.3% of 4-hour tests and 95% of 20-hour tests. The result of the 4-hour direct test differed from that of the 20-hour direct test on 2.8% of occasions, and from those of the 4-hour indirect and the 20-hour indirect test on more than 5% of occasions. Discrepancies occurred about twice as often with staphylococci as with enterobacteria.
A RAPID DETERMINATION OF BACTERIAL ANTIBIOTIC SENSITIVITY IN MIXED CULTURE
Authors: Mahony D. E. , Chadwick P.
Published: February 2010

A means of determining the antibiotic sensitivity of a known pathogen in a mixture of organisms of varying antibiotic sensitivity is described. Such a technique involved the combination of a rapid antibiotic-sensitivity test in which the criterion of sensitivity was the inhibition of microcolony formation on the surface of agar plates containing antibiotic and the fluorescent-antibody reaction used in the rapid identification of bacteria. It was possible to determine the antibiotic sensitivity of enteropathogenic Escherichia coli in artificially mixed cultures within 5 hours by this method.
SELENITE REDUCTION BY SALMONELLA HEIDELBERG
Authors: McCready R. G. L. , Campbell J. N. , Payne J. I.
Published: February 2010

When Salmonella Heidelberg is grown in 0.1% w/v Na2SeO3and examined microscopically during growth, two morphological changes can be seen. Red intracellular granules are seen in most of the population within 10 to 12 hours, and organisms containing granules elongate without cell division. The intracellular granules produced by S. heidelberg in selenite broth have been identified by X-ray analysis as amorphous red selenium. The intermediate in the conversion of selenite to elemental selenium has been trapped and identified as divalent selenium ion. Growth studies have shown that selenite toxicity is primarily associated with the lag phase of growth, and also that the divalent intermediate is more toxic than the tetravalent precursor.
THE CONGO RED REACTION IN BACTERIA AND ITS USEFULNESS IN THE IDENTIFICATION OF RHIZOBIA
Authors: Hahn N. J.
Published: February 2010

Congo red was found in this research to form colloidal complexes with di-and tri-valent cations in the presence of acid and alkali. The complexes formed at a pH of 2–3 were uniformly blue; those formed at a pH greater than 12 varied in color with the ion involved, a fuchsia complex being formed with magnesium. The congo red reaction in bacteria (e.g. coloration of the growth in media containing the dye) is explained as due to the adsorption of Congo red on the surface of the bacterial cell, to the ions which predominate at the surface, and to the production of acid or alkali by the bacterium during growth. The temperature of incubation and composition of the growth medium influence colony coloration by affecting the metabolism of the organism.A negative form of selection for rhizobia is suggested using a nitrogen-deficient and a nitrogen-rich carbohydrate medium containing 0.25 g Congo red per liter of agar and 0.025 g Congo red per liter of broth, with incubation at 28 °C and 37 °C respectively. Color differentiation among the rhizobial strains tested, four normal and seven mutant varieties of Rhizobium meliloti and Rhizobium trifolii, occurred on the nitrogen-rich agar medium when incubation was carried out at 25 °C to 28 °C.
UTILIZATION OF GLYCEROL BY ACETOBACTER ACETIGENUM UNDER DIFFERENT CULTURAL CONDITIONS
Authors: Ramamurti K. , Jackson C. P.
Published: February 2010

A comparative study has been made of the use of glycerol by Acetobacier acetigenum inalactate-buffered glycerol medium under different cultural conditions. Cellulose, the principal product formed by the action of this microorganism on the substrate, was removed before the residual glycerol was estimated. The amount of cellulose formed in the defined medium was determined at each stage of the experimental period. The use of glycerol was followed by estimating the amount of glycerol remaining in the medium at different stages of growth of the organism. The results of the inquiry indicate a more complete use of the substrate by the bacterium in shaken cultures than under static conditions. Cellulose formation seems to be best in shaken cultures (lactate-buffered glycerol medium) whereas the yield of cellulose is considerably diminished in static cultures.
STRAIN DEGENERATION DURING CONTINUOUS CULTURE OF A CHLORAMPHENICOL-PRODUCING STREPTOMYCES VENEZUELAE
Authors: Sala F. , Westlake D. W. S.
Published: February 2010

Instability of growth characteristics and chloramphenicol production was observed during long-term continuous cultivations of a Streptomyces sp. The occurrence of these variations was attributed to a continuous population selection.Fermentation patterns are presented for growth in a complex and in a synthetic medium, at different replacement times. The culture degeneration pattern was influenced by the type of medium used and by the replacement time. A rich complex medium created the most favorable conditions for the maintenance of an antibiotic-producing population.Growth on the walls took place when cultures were grown in the complex medium with a fast replacement time. Under these conditions no decrease in chloramphenicol yield was observed, even after 76 replacements of the medium. Possibly a population closely related to the initial one was maintained on the walls, and thus replacement by non-producing populations was avoided. Application of this method is suggested as a means for maintenance of culture stability in continuous industrial fermentation.
THE ANTIBACTERIAL ACTIVITY OF MARINE PLANKTONIC ALGAE
Authors: Duff D. C. B. , Bruce D. L. , Antia N. J.
Published: February 2010

Cell extracts of 14 species of marine phytoplankters belonging to six algal classes were tested for antibacterial activity against 9 marine isolates and 14 strains of terrestrial saprophytes including potential pathogens. Apart from individual species differences, some noteworthy differences in antibiotic effectiveness were observed between the algal classes. The Bacillariophyceae, Chrysophyceae, and Cryptophyceae showed considerably greater range and degree of activity than the Chlorophyceae, while the coccoid Myxophyceae showed no detectable activity. The single species of Dinophyceae examined appeared to be comparable in activity to the Cryptophyceae. The observed spectrum of activity indicated selective action against marine isolates and against Gram-positive organisms. In the latter group, three Staphylococcus strains were particularly susceptible to algal antibiotic action. Some of the algal species showed both growth inhibition and growth stimulation of specific test bacteria. The occasional development of antibiotic-resistant colonies within inhibition zones was noted.
EFFECT OF FERROCYANIDE ON GROWTH AND CITRIC ACID PRODUCTION BY ASPERGILLUS NIGER
Authors: Horitsu H. , Clark D. S.
Published: February 2010

Ferrocyanide at concentrations of less than 30 p.p.m. (the amount tolerated in citric acid fermentation of beet molasses) had no measurable effect on citric acid production or on the oxidation of glucose or Krebs cycle compounds by resting cells of Aspergillus niger or on the growth rate of this organism during submerged fermentation of beet molasses. Concentrations above 30 p.p.m., however, stimulated citric acid formation in resting cells, but markedly inhibited cell development in growing cells. This inhibition of growth was the main cause of the detrimental effect of high concentrations of ferrocyanide on citric acid formation in molasses; good growth throughout the fermentation was essential to high acid yield, inhibition of growth could be released at any time during the fermentation by addition of sufficient ZnSO4 to reduce the ferrocyanide content to below 30 p.p.m. No evidence that ferrocyanide favors citric acid accumulation by blocking a reaction in the Krebs cycle was found.
CLAVINE ALKALOID FORMATION IN SUBMERGED CULTURES OF A CLAVICEPS SPECIES
Authors: Vining L. C. , Nair P. M.
Published: February 2010

The role of major nutrients in a glucose – mannitol – ammonium succinate – mineral salts medium which supports high production of clavine alkaloids was examined. Mannitol was found to be superior to other carbohydrates as a source of carbon but, under certain conditions, could be partially replaced with glucose. Ammonia provided the most suitable source of nitrogen, and was best supplied as ammonium succinate. In media with glucose and mannitol as principal carbon source, ammonium and succinate ions were utilized at parallel rates, maintaining the pH of the culture within the favorable range of 5.5–6.5 during alkaloid formation. For maximum yields there were optimum values for the initial concentrations of ammonia and phosphate in the medium. The concentration of phosphate required was growth-limiting. A high carbon:nitrogen ratio was necessary to prolong the phase of alkaloid synthesis. Production was increased by the "addition of L-tryptophan but not DL-mevalonic acid. The advantages of this medium for promoting alkaloid formation appear to be limited to clavine-producing strains isolated from Pennisetum typhoideum.
OXIDATION OF INORGANIC SULFUR COMPOUNDS BY WASHED CELL SUSPENSIONS OF THIOBACILLUS FERROOXIDANS
Authors: Landesman J. , Duncan D. W. , Walden C. C.
Published: February 2010

Oxidation of various inorganic sulfur compounds by Thiobacillus ferrooxidans was studied, and conditions necessary for maximum respiration rates were established. Optimum oxidation of elemental sulfur occurred at pH 5.0 and gave a Qo2(N) of 726; oxidation of thiosulfate gave a maximum Qo2(N) of 514 at pH 4.0; tetra- and tri-thionate, when oxidized at pH 6.0, gave a maximum Qo2(N) of 103 and 113, respectively. Polythionates accumulated during thiosulfate oxidation, but did not during oxidation of elemental sulfur. Metallic sulfide minerals were oxidized optimally as follows: chalcopyrite, pH 2.0, maximum Qo2(N) 3200; bornite, pH 3.0, maximum Qo2(N) 450; pyrite, pH 2.0, maximum Qo2(N) 1600. Maximum temperature for oxidation of all inorganic sulfur compounds tested was 40 C.The effect of a variety of organic compounds on sulfur oxidation is presented.T. ferrooxidans requires growth adaptation on iron for maximum respiration on that substrate; however, sulfur oxidation is not inducible. Iron and sulfur can be oxidized simultaneously, giving a rate equal to the sum of the maximum rates of oxidation of the two substrates individually.
QUALITATIVE ANALYSES OF VEGETATIVE CELL WALLS AND SPORE WALLS OF SOME REPRESENTATIVE SPECIES OF STREPTOMYCES
Authors: DeJong Peter J. , McCoy Elizabeth
Published: February 2010

Vegetative cell walls and spore walls of seven Streptomyces species representing four types of spore morphology were qualitatively analysed for their components. Amino acid and carbohydrate components (glucose, glucosamine, muramic acid, diaminopimelic acid, glutamic acid, glycine, alanine, arginine, threonine, valine, leucine, and aspartic acid) in both types of walls were identical in all species. Aspartic acid was a major component in spore walls, but a minor component in vegetative cell walls. Although organic phosphate was present in both vegetative- and spore-wall hydrolysates, the other components of teichoic acid were not found nor was teichoic acid extracted from the isolated walls by cold trichloroacetic acid. A portion of the vegetative cell wall was rendered soluble with lysozyme and separated by paper electrophoresis into two fractions detected with ninhydrin. The lysozyme-resistant portion of the vegetative cell wall showed the same major and minor components as the spore walls, which are also lysozyme resistant.
PROPERTIES OF FOUR HERELLEA PHAGES
Authors: Blouse Louis , Twarog R.
Published: February 2010

The isolation of four Herellea phages is described. The phages are tailed forms varying in overall length from 180 to 220 mμ. Except in one instance the phages are host specific. Some serological relatedness is observed. Grown at 37 °C in broth, the phages have latent periods of 23 to 31 min. The average burst for the phages varies from 12 to 148 plaque-forming units per bacterium. Buoyant densities for these phages range from 1.507 to 1.523 g/cm3.
MODE OF ATTACK ON PHENOL BY A MICROCOCCUS SP. ISOLATED FROM COIR RETS
Authors: Jayasankar N. P. , Bhat J. V.
Published: February 2010

Phenol enrichments of coir rets resulted in the isolation of Pseudomonas desmolytica, Pseudomonas fragi, Pseudomonas dacunhae, and Micrococcus varians. The inducible phenol hydroxylase of M. varians obtained in a crude form showed maximal activity at pH 7.5. Evidence was adduced to show that the ring-cleaving enzyme of M. varians was of the metapyrocatechase type. The M. varians strains when cultured in phenol medium elaborated a diffusible melanin-like pigment. Ethyl acetate soluble fraction of the pigment was identified as 3,4,3′,4′-tetrahydroxy diphenyl. The effect of certain aromatic compounds and copper binders on pigmentation was investigated.
INFLUENCE OF RESISTANT AND SUSCEPTIBLE VARIETIES OF MUSKMELON ON SIZE OF POPULATIONS OF THE FUSARIUM WILT FUNGUS AND WILT IN NATURALLY INFESTED SOILS
Authors: Wensley R. N. , McKeen C. D.
Published: February 2010

Under greenhouse conditions soils naturally infested with the muskmelon wilt fungus and planted to the resistant variety, Harvest Queen, showed either slight decreases in populations or maintenance of levels near those of the preceding planting or fallow. In contrast, successive plantings of a susceptible variety, Perfection, increased the size of the population and the wilt incidence of soils to high levels. In fallow soils populations of the wilt fungus remained fairly constant.
MIGRATION OF BACTERIA ON SEEDLING PLANTS
Authors: Leben Curt , Daft Gilbert C.
Published: February 2010

Cucumber, maize, and soybean seeds were dipped in dilute suspensions of cells of isolates A169 or A180, culturally distinctive marker bacteria originally isolated from cucumber leaves. Seeds were planted in an autoclaved rooting medium. The relative humidity of the air around shoots was greater than 90%. Distribution of the marker bacteria and of other bacteria normally carried by seed (termed normal bacteria) was characteristic on shoots of a given plant species, as determined by printing shoot parts on agar. Bacteria occurred uniformly on prints of all parts of cucumber shoots. On prints of maize shoots, distribution was patchy, with large areas of leaves apparently carrying no bacteria. Bacteria were confined mostly to the lower stem of soybean. On prints of shoots of plants from seeds treated with a marker organism, usually the marker and normal bacteria were intermixed. Marker and normal bacteria were detected in abundance on roots of all three plant species. When marker bacteria were placed on loops of string around stems of cucumber seedlings, the markers did not migrate to other parts of plants.
AN ELECTRON MICROSCOPE STUDY OF THIN SECTIONS OF HAEMOPHILUS VAGINALIS (GARDNER AND DUKES) AND SOME POSSIBLY RELATED SPECIES
Authors: Reyn Alice , Birch-Andersen A. , Lapage S. P.
Published: February 2010

The line structure of Haemophilus vaginalis (Gardner and Dukes 1955) was compared with that of four, possibly related species (Butyribacterium rettgeri, Corynebacterium diphtheriae var. mitis, Lactobacillus acidophilus, Haemophilus influenzae) and an unrelated species, Neisseria haemolysans, which had shown a similar degree of Gram-variability as that of H. vaginalis. Although H. vaginalis was first described as a Gram-negative rod, its fine structure, particularly that of cell wall and septa, was more like that of Gram-positive organisms. Also N. haemolysans had a fine structure close to that of Gram-positive organisms, and its typical Gram-positive cell wall varied in. thickness from one cell to another.The study did not solve the problem of the classification of the so-called H. vaginalis, but the appearance of the few strains studied in the electron microscope suggests that it: should be included in Corynebacterium or Butyribacterium rather than in Lactobacillus.
THE MODE OF ACTION OF THE ANTIBIOTIC PAROMOMYCIN ON STAPHYLOCOCCUS AUREUS
Authors: Seefried A. von , Jordan D. C.
Published: February 2010

Paromomycin (Humatin, Parke Davis & Co.), a broad-spectrum aminoglycosidic antibiotic, inhibits the incorporation of amino acids into the trypsinsoluble protein fraction of Staphylococcus aureus 257. Protein synthesis is inhibited immediately, but the synthesis of cell-wall mucopeptide and alcohol-soluble proteins and lipids is not affected for approximately 35 min after antibiotic addition to actively growing cells. Paromomycin, at the ribosomal level, prevents the attachment of amino acyl-s-RNA and causes accumulation of m-RNA.Divalent cations (Ca++ and Mg++) antagonize the bactericidal action of paromomycin and interfere with the in vivo binding of the antibiotic on both the cell surface and the intracellular binding sites. In vitro binding to free ribosomes can be prevented and reversed by both monovalent and divalent cations.Using a "cylinder-plate" method, involving the displacement of antibiotic from cellular fractions by 0.2 M MgCl2, the antibiotic can be recovered from the ribosomes, cytoplasm, and the cell wall of paromomycin-sensitive S. aureus cells, but is not found in any of these fractions isolated from paromomycin-resistant cells developed from the sensitive parent strain. The resistant mutants apparently have lost the ability to adsorb and transport the antibiotic into the cell.
PRODUCTION OF GREEN ALGAE IN DEUTERIUM OXIDE
Authors: Williams A. J. , Morse A. T. , Stuart R. S.
Published: February 2010

The two species of green algae Scenedesmus obliquus and Chorella vulgaris were successfully adapted and grown in 99.7% deuterium oxide in 15-liter culture units. These units average 50 to 60 g of dry cells every 10 to 12 days. The deuterium oxide used in the media was recycled after purification to maintain usage at practical values.
THE INACTIVATION AND REACTIVATION OF A PROTEUS RETTGERI PHAGE IN SALT SOLUTIONS
Authors: Stewart Robert B. , Gandhi Sunil S. , Milazzo Francis H. , Hinton Norman A.
Published: February 2010

A phage isolated from a strain of Proteus rettgeri was studied with respect to its behavior in salt solutions. Infectivity was lost when phage was exposed to dilute salt solutions but regained when the phage was transferred to more concentrated solutions. Investigation of the effect of temperature on this phenomenon indicated that two inactivating mechanisms were involved; one associated with temperature was not reversible, whereas salt inactivation was reversible.Studies of phage attachment: showed a two-stage sequence, the first reversible the second irreversible. Phage inactivated in dilute salt solution was found to attach to bacterial cells, hence salt inactivation is not explained by inhibition of attachment.
Cross-population responses to conspecific chemical alarm cues in wild Trinidadian guppies, Poecilia reticulata: evidence for local conservation of cue production
Authors: Brown Grant E. , Elvidge Chris K. , Macnaughton Camille J. , Ramnarine Indar , Godin Jean-Guy J.
Published: February 2010

Within freshwater fishes, closely related species produce alarm cues that are chemically similar, leading to conserved antipredator responses. Similar conservation trends are predicted for species with geographically isolated populations. Here, we tested this hypothesis with the guppy ( Poecilia reticulata Peters, 1859) from two populations within the Aripo River, Trinidad. Free-ranging guppies in the Lower Aripo (high-predation population) exhibited more risk-aversive inspection behaviour towards a fish predator model paired with the alarm cues of guppies collected from the same population versus a river water control. In comparison, when paired with the alarm cues of guppies from the Upper Aripo (low-predation population), the response was intermediate. In the laboratory, we tested Upper and Lower Aripo guppies to the alarm cues of the same or different Aripo River donors, Quaré River guppies (a high-predation population from a different drainage), or a water control. Both Upper and Lower Aripo River guppies exhibited the highest intensity response to donors from the same population and the lowest intensity response to Quaré River donors, with the response to different Aripo donors being intermediate. Collectively, these results demonstrate a trend of intraspecific conservation of chemical alarm cue production, leading to population-specific responses to conspecific cues.
Comparison of human and porcine gastric clasp and sling fiber contraction by M2and M3muscarinic receptors
Authors: Vegesna Anil K. , Braverman Alan S. , Miller Larry S. , Tallarida Ronald J. , Tiwana Mansoor I. , Khayyam Umar , Ruggieri Michael R.
Published: February 2010

To compare the gastroesophageal junction of the human with the pig, M2and M3receptor densities and the potencies of M2and M3muscarinic receptor subtype selective antagonists were determined in gastric clasp and sling smooth muscle fibers. Total muscarinic and M2receptors are higher in pig than human clasp and sling fibers. M3receptors are higher in human compared with pig sling fibers but lower in human compared with pig clasp fibers. Clasp fibers have fewer M3receptors than sling fibers in both humans and pigs. Similar to human clasp fibers, pig clasp fibers contract significantly less than pig sling fibers. Analysis of the methoctramine Schild plot suggests that M2receptors are involved in mediating contraction in pig clasp and sling fibers. Darifenacin potency suggests that M3receptors mediate contraction in pig sling fibers and that M2and M3receptors mediate contraction in pig clasp fibers. Taken together, the data suggest that both M2and M3muscarinic receptors mediate the contraction in both pig clasp and sling fibers similar to human clasp and sling fibers.
Impaired cardiovascular function in primary biliary cirrhosis
Authors: Jones David E. J. , Hollingsworth Kieren , Fattakhova Gulnar , MacGowan Guy , Taylor Roy , Blamire Andrew , Newton Julia L.
Published: February 2010

Cardiovascular system dysregulation in the form of autonomic dysfunction is common at all stages of the disease process in the autoimmune liver disease primary biliary cirrhosis (PBC) and associates with the symptom of fatigue. The mechanisms underpinning autonomic dysfunction in PBC are, however, at present unclear. In this study we set out to explore, for the first time, cardiac structure and function in PBC using impedance cardiography (ICG) and magnetic resonance methodologies. ICG was assessed beat to beat in response to orthostasis (by head-up tilt) in age and sex case-matched high-fatigue and low-fatigue PBC groups (assessed by Fatigue Impact Scale), normal control subjects ( n = 15 each group) and a liver disease control cohort (primary sclerosing cholangitis). Cardiac structure and bioenergetics were examined in 15 of the PBC subjects and 8 of the normal control subjects by magnetic resonance spectroscopy and cine imaging. Capacity of the left ventricle to respond to orthostasis [left ventricular ejection time (LVET)] was impaired in PBC compared with matched normal control subjects ( P = 0.05). This was a PBC-specific phenomenon unrelated to fatigue status. PBC patients exhibited significantly lower cardiac muscle phosphocreatine-to-ATP ratio (PCr/ATP ratio; measure of cardiac bioenergetic integrity) compared with control subjects ( P < 0.01). PCr/ATP <1.6 (indicative of increased risk of death in cardiomyopathy) was present in 6/15 (40%) PBC patients (0/8 control subjects; P < 0.05). Cardiac structure and function were similar in all measures of left ventricular morphology between control subjects and PBC. The close relationship between PCr/ATP and LVET seen in normal subjects ( r2 = 0.6; P < 0.05) was lost in PBC patients, a finding compatible with myocardial dysfunction. Significant correlation was seen between fatigue severity in PBC and fall in cardiac output on orthostasis ( r2 = 0.25; P = 0.005). Our findings suggest the presence of altered myocardial function in PBC. Autonomic “dysfunction” may, rather than being an abnormal process, represent a compensatory mechanism to increase cardiac return to mitigate these effects.
Effect of 2-wk intensified training and inactivity on muscle Na+-K+pump expression, phospholemman (FXYD1) phosphorylation, and performance in soccer players
Authors: Thomassen Martin , Christensen Peter M. , Gunnarsson Thomas P. , Nybo Lars , Bangsbo Jens
Published: February 2010

The present study examined muscle adaptations and alterations in performance of highly trained soccer players with intensified training or training cessation. Eighteen elite soccer players were, for a 2-wk period, assigned to either a group that performed high-intensity training with a reduction in the amount of training (HI, n = 7), or an inactivity group without training (IN, n = 11). HI improved ( P < 0.05) performance of the 4th, 6th, and 10th sprint in a repeated 20-m sprint test, and IN reduced ( P < 0.05) performance in the 5th to the 10th sprints after the 2-wk intervention period. In addition, the Yo-Yo intermittent recovery level 2 test performance of IN was lowered from 845 ± 48 to 654 ± 30 m. In HI, the protein expression of the Na+-K+pump α2-isoform was 15% higher ( P < 0.05) after the intervention period, whereas no changes were observed in α1- and β1-isoform expression. In IN, Na+-K+pump expression was not changed. In HI, the FXYD1ser68-to-FXYD1 ratio was 27% higher ( P < 0.01) after the intervention period, and, in IN, the AB_FXYD1ser68 signal was 18% lower ( P < 0.05) after inactivity. The change in FXYD1ser68-to-FXYD1 ratio was correlated ( r2= 0.35; P < 0.05) with change in performance in repeated sprint test. The present data suggest that short-term intensified training, even for trained soccer players, can increase muscle Na+-K+pump α2-isoform expression, and that cessation of training for 2 wk does not affect the expression of Na+-K+pump isoforms. Resting phosphorylation status of the Na+-K+pump is changed by training and inactivity and may play a role in performance during repeated, intense exercise.
Modulation of intracellular calcium transient in response to β-adrenoceptor stimulation in the hearts of 4-wk-old rats during simulated weightlessness
Authors: Cui Yan , Zhang Shu-Miao , Zhang Quan-Yu , Fan Rong , Li Juan , Guo Hai-Tao , Bi Hui , Wang Yue-Min , Hu Yu-Zhen , Zheng Qi-Jun , Gu Chun-Hu , Yu Shi-Qiang , Yi Ding-Hua , Li Zhi-Chao , Pei Jian-Ming
Published: February 2010

Modulation of intracellular calcium ([Ca2+]i) transient in response to β-adrenoceptor stimulation in the hearts of hindlimb unweighted (HLU) rats during simulated weightlessness has not been reported. In the present study, we adopted the rat tail suspension for 4 wk to simulate weightlessness. Effects of simulated microgravity on β-adrenoceptor responsiveness were then studied. Mean arterial blood pressure, left ventricular pressure (LVP), systolic function [maximum positive change in pressure over time (+dP/d tmax)], and diastolic function [maximum negative change in pressure over time (−dP/d tmax)] were monitored during the in vivo experiment. β-Adrenoceptor density was quantitated by radioactive ligand binding. Single rat ventricular myocyte was obtained by enzymatic dissociation method. ±dP/d tmax, myocyte contraction, intracellular [Ca2+]itransient, and L-type calcium current in response to β-adrenoceptor stimulation with isoproterenol were measured. Compared with the control group, no significant changes were found in heart weight, body weight, and mean arterial blood pressure, whereas LVP and ±dP/d tmaxwere significantly reduced. LVP and ±dP/d tmaxwere significantly attenuated in the HLU group in response to isoproterenol administration. In the in vitro study, the β-adrenoceptor density was unchanged. Effects of isoproterenol on electrically induced single-cell contraction and [Ca2+]itransient in myocytes of ventricles in HLU rats were significantly attenuated. The enhanced L-type Ca2+current elicited by isoproterenol in cardiomyocytes was significantly decreased in the HLU group. The above results indicate that impaired function of L-type Ca2+current and decreased [Ca2+]itransient cause the depressed responsiveness of the β-adrenoceptor stimulation, which may be partially responsible for the depression of cardiac function.
Lactic acidosis in vivo: testing the link between lactate generation and H+ accumulation in ischemic mouse muscle
Authors: Marcinek David J. , Kushmerick Martin J. , Conley Kevin E.
Published: February 2010

The link between lactate generation and cellular acidosis has been questioned based on the possibility of H+ generation, independent of lactate production during glycolysis under physiological conditions. Here we test whether glycolytic H+ generation matches lactate production over a physiological pH and lactate range using ischemia applied to the hindlimb of a mouse. We measured the H+ generation and ATP level in vivo using 31P-magnetic resonance spectroscopy and chemically determined intracellular lactate level in the hindlimb muscles. No significant change was found in ATP content by chemical analysis ( P > 0.1), in agreement with the stoichiometric decline in phosphocreatine (20.2 ± 1.2 mM) vs. rise in Pi (18.7 ± 2.0 mM), as measured by 31P-magnetic resonance spectroscopy. A substantial drop in pH from 7.0 to 6.7 and lactate accumulation to 25 mM were found during 25 min of ischemia. The rise in H+ generation closely agreed with the accumulation of lactate, as shown by a close correlation with a slope near identity (0.98; r2 = 0.86). This agreement between glycolytic H+ production and elevation of lactate is confirmed by an analysis of the underlying reactions involved in glycolysis in vivo and supports the concept of lactic acidosis under conditions that substantially elevate lactate and drop pH. However, this link is expected to fail with conditions that deplete phosphocreatine, leading to net ATP hydrolysis and nonglycolytic H+ generation. Thus both direct measurements and an analysis of the stoichiometry of glycolysis in vivo support lactate acidosis as a robust concept for physiological conditions of the muscle cell.
Central chemoreception in wakefulness and sleep: evidence for a distributed network and a role for orexin
Authors: Nattie Eugene , Li Aihua
Published: February 2010

This minireview examines data showing the locations of central chemoreceptor sites as identified by the presence of ventilatory responses to focal, mild acidification produced in unanesthetized animals in vivo, how the site-specific responses vary by arousal state, and what the emerging role of orexin might be in this state-dependent central chemoreceptor system. We comment on the organization of this distributed central chemoreceptor system and suggest that interactions among sites are synergistic and not additive, which is an important aspect of its normal function.
The role of medullary serotonin (5-HT) neurons in respiratory control: contributions to eupneic ventilation, CO2chemoreception, and thermoregulation
Authors: Hodges Matthew R. , Richerson George B.
Published: February 2010

The functional roles of the medullary raphé, and specifically 5-HT neurons, are not well understood. It has previously been stated that the role of 5-HT has been so difficult to understand, because “it is implicated in virtually everything, but responsible for nothing”(Cowen PJ. Foreword. In: Serotonin and Sleep: Molecular, Functional and Clinical Aspects, edited by Monti JM, Prandi-Perumal SR, Jacobs BL, Nutt DJ. Switzerland: Birkhauser, 2008). Are 5-HT neurons important, and can we assign a general, or even specific, function to them given their diffuse projections? Recent data obtained from transgenic animals and other model systems indicate that the 5-HT system is not expendable, particularly during postnatal development, and likely plays specific roles in vital functions such as respiratory and thermoregulatory control. We recently provided a detailed and updated review of one specific function of 5-HT neurons, as central respiratory chemoreceptors contributing to the brain's ability to detect changes in pH/CO2and stimulate adjustments to ventilation accordingly ( 9 ). Here, we turn our focus to recent data demonstrating that 5-HT neurons provide an essential excitatory drive to the respiratory network. We then further discuss their role in the CO2chemoreflex, as well as other homeostatic functions that are closely related to ventilatory control. Last, we provide additional hypotheses/concepts that are worthy of further study, and how 5-HT neurons may be involved in human disease.
The insulin-like growth factor (IGF)-I E-peptides are required for isoform-specific gene expression and muscle hypertrophy after local IGF-I production
Authors: Barton Elisabeth R. , DeMeo J , Lei Hanqin
Published: February 2010

Insulin-like growth factor I (IGF-I) coordinates proliferation and differentiation in a wide variety of cell types. The igf1 gene not only produces IGF-I, but also generates multiple carboxy-terminal extensions, the E-peptides, through alternative splicing leading to different isoforms. It is not known if the IGF-I isoforms share a common pathway for their actions, or if there are specific actions of each protein. Viral administration of murine IGF-IA, IGF-IB, and mature IGF, which lacked an E-peptide extension, was utilized to identify IGF-I isoform-specific responsive genes in muscles of young growing mice. Microarray analysis revealed responses that were driven by increased IGF-I regardless of the presence of E-peptide, such as Bcl-XL. In contrast, distinct expression patterns were observed after viral delivery of IGF-IA or IGF-IB, which included matrix metalloproteinase 13 (MMP13). Expression of Bcl-XL was prevented when viral administration of the IGF-I isoforms was performed into muscles of MKR mice, which lack functional IGF-I receptors on the muscle fibers. However, MMP13 expression persisted under the same conditions after viral injection of IGF-IB. At 4 mo after viral delivery, expression of IGF-IA or IGF-IB promoted muscle hypertrophy, but viral delivery of mature IGF-I failed to increase muscle mass. These studies provide evidence that local production of IGF-I requires the E-peptides to drive hypertrophy in growing muscle and that both common and unique pathways exist for the IGF-I isoforms to promote biological effects.
Regulation of Ionotropic Glutamate Receptors by Their Auxiliary Subunits
Authors: Tomita Susumu
Published: February 2010

Glutamate receptors are major excitatory receptors in the brain. Recent findings have established auxiliary subunits of glutamate receptors as critical modulators of synaptic transmission, synaptic plasticity, and neurological disorder. The elucidation of the molecular rules governing glutamate receptors and subunits will improve our understanding of synapses and of neural-circuit regulation in the brain.
Phagocytosis of Retinal Rod and Cone Photoreceptors
Authors: Kevany Brian M. , Palczewski Krzysztof
Published: February 2010

Photoreceptor cells maintain a roughly constant length by continuously generating new outer segments from their base while simultaneously releasing mature outer segments engulfed by the retinal pigment epithelium (RPE). Thus postmitotic RPE cells phagocytose an immense amount of material over a lifetime, disposing of photoreceptor cell waste while retaining useful content. This review focuses on current knowledge of outer segment phagocytosis, discussing the steps involved along with their critical participants as well as how various perturbations in outer segment (OS) disposal can lead to retinopathies.
Stretch-Activated Ion Channels: What Are They?
Authors: Sachs Frederick
Published: February 2010

Mechanosensitive ion channels (MSCs) exist in all cells, but mechanosensitivity is a phenotype not a genotype. Specialized mechanoreceptors such as the hair cells of the cochlea require elaborate mechanical impedance matching to couple the channels to the external stress. In contrast, MSCs in nonspecialized cells appear activated by stress in the bilayer local to the channel—within about three lipids. Local mechanical stress can be produced by far-field tension, amphipaths, phase separations, the cytoskeleton, the extracellular matrix, and the adhesion energy between the membrane and a patch pipette. Understanding MSC function requires under standing the stimulus.
Clinical Comparison of 12 mg Ropivacaine and 8 mg Bupivacaine, Both with 20 µg Fentanyl, in Spinal Anaesthesia for Major Orthopaedic Surgery in Geriatric Patients
Authors: Erturk Engin , Tutuncu Cigdem , Eroglu Ahmet , Gokben Merih
Published: February 2010

Objective: The aim of this study was to compare the haemodynamic and anaesthetic effects of 12 mg ropivacaine and 8 mg bupivacaine, both with 20 µg fentanyl, in spinal anaesthesia for major orthopaedic surgery in geriatric patients. Subjects and Methods: Sixty American Society of Anesthesiologists (ASA) II–III patients scheduled for hip arthroplasty were randomly assigned to receive an intrathecal injection of either 12 mg ropivacaine with 20 µg fentanyl (group R, aged 70 ± 7 years, range 67–89) or 8 mg hyperbaric bupivacaine with 20 µg fentanyl (group B, aged 69 ± 6 years, range 66–92). Motor and sensory block, haemodynamics and side effects were recorded. Results: Mean levels of sensory block were similar, but the onset time of sensory block in group B (2.52 ± 0.69 min) was shorter than that in group R (3.17–0.72 min); the difference was statistically significant (p < 0.01), and the number of patients who had motor Bromage scale 3 in group B (24) was greater than in group R (16). The difference was also statistically significant (p < 0.05). Systolic and diastolic arterial pressures (SAP, DAP) and heart rate (HR) decreased after the block in both groups. SAP (after the 60th and 120th min of block), DAP (all measurement times), and HR (after the 20th, 25th and 30th min of block) were lower in group B than in group R. Conclusions: The data showed that 12 mg of ropivacaine and 8 mg of bupivacaine with 20 µg fentanyl in spinal anaesthesia can provide sufficient motor and sensory block for major orthopaedic surgery in geriatric patients. However, ropivacaine caused less motor block and haemodynamic side effects than bupivacaine during the procedure.
Polymorphisms in NOS3, ACE and PAI-1 Genes and Risk of Spontaneous Recurrent Miscarriage in the Gaza Strip
Authors: Al Sallout Rami J. , Sharif Fadel A.
Published: February 2010

Objective: This study was conducted to investigate the correlation between spontaneous recurrent miscarriage (RM) and common polymorphisms in angiotensin-converting enzyme (ACE), plasminogen activator inhibitor 1 (PAI-1) and endothelium-derived nitric oxide synthase 3 (NOS3) genes among women experiencing RM in the Gaza Strip. Methods: The presence of these genetic profiles was determined for 100 women who had had at least 3 constitutive abortions and 100 controls without any history of abortion using molecular biological techniques. Results: The ACE D/D polymorphism was present in 49% of the study population and in 54% of the controls (p = 0.479). Similarly, there was no significant difference detected in the distribution of polymorphisms for PAI-1, with the 4G/4G genotype present in the study group and in controls (p = 1.00). NOS3 4a/4a was present in 4% of the study group and in none of the 100 controls (p = 0.123). In this study, we also discovered a new variant in the NOS3 gene which was named 4c allele and was encountered in 1 patient and in 1 control subject. Conclusion: There was no significant association between ACE I/D, PAI-1 4G/5G and NOS3 4a/4b and the occurrence of first-trimester RM. In-depth investigation of the association of NOS3 4a/4a with RM is strongly recommended.
Influence of Diabetes on the Outcome of Acute Coronary Syndrome in Kuwait
Authors: Saad Hisham , Sawan Sana , Rashed Wafa , Zubaid Mohammad
Published: February 2010

Objectives: To describe the baseline characteristics and management of patients with and without diabetes mellitus (DM) hospitalized with acute myocardial infarction (AMI) and to assess the influence of DM on hospital outcomes and hospital mortality. Subjects and Methods: We analyzed data from a 6-month observational study (Kuwait Acute Coronary Syndrome Registry) of unselected patients admitted with a diagnosis of AMI over a period of 6 months, from December 2003 through May 2004. Results: Of 1,295 patients enrolled, 609 (47%) were diabetics and 686 (53%) were non-diabetics. Diabetics were more likely to have a past history of coronary artery disease, hypertension and left ventricular systolic dysfunction than non-diabetics. There was less use of β-blockers and aspirin in diabetics as compared to non-diabetics (62 vs. 71% and 95.5 vs. 97.9%, p < 0.03, for β-blockers and aspirin, respectively). Left ventricular failure and cardiogenic shock occurred more often in diabetics compared to non-diabetics (16 vs. 7% and 5 vs. 3%, p < 0.001, for left ventricular failure and shock, respectively). The mortality rate was 6% for diabetics and 2% for non-diabetics (p < 0.001). Conclusion: DM is a major health problem among the adult population in Kuwait, and almost half the AMI population suffer from diabetes. Diabetic patients had higher rates of complications, especially left ventricular failure and cardiogenic shock, as compared to non-diabetic patients. The in-hospital mortality among diabetics with AMI was almost triple that of non-diabetics. The results of this study highlight the need to improve adherence to evidence-based treatment in diabetic patients with AMI.
Comparison of Conventional versus Colored Compomers for Class II Restorations in Primary Molars: A 12-Month Clinical Study
Authors: Ertugrul Fahinur , Cogulu Dilsah , Özdemir Yasemin , Ersin Nazan
Published: February 2010

Objective: To evaluate the 12-month clinical performance of conventional (Compoglass F) and colored (Twinky Star) compomer restorative materials in class II restorations of primary molars. Materials and Methods: A total of 196 restorations were placed in 98 children aged between 5 and 10 years (mean age: 7.43 ± 1.31 years) who had bilateral matched pairs of carious posterior class II primary molars. A split-mouth design was used in which 2 materials (Compoglass F, Twinky Star) were randomly placed on contralateral sides by 3 dentists. At baseline, after 6 and after 12 months, the restorations were evaluated using modified US Public Health Service criteria for: secondary caries, marginal integrity, marginal discoloration, anatomic form and surface texture. The Alpha and Bravo scores were considered as clinical success. The data were subjected to statistical analysis by the Wilcoxon and McNemar tests (p < 0.05). The Kaplan-Meier survival method was applied to estimate survival percentages. Results: No significant difference was found among the groups at all recalls regarding marginal integrity, marginal discoloration, anatomic form, secondary caries and surface texture. The 12-month mean cumulative survival rate of Compoglass F was 95.7%, while in the Twinky Star group, the survival rate was 93% in class II restorations with no significant difference between the groups for either material. Conclusion: Both conventional and colored compomer materials are suitable restorative materials for primary teeth for at least 12 months. Colored compomers could also be a good alternative to tooth-colored compomers in the restoration of primary molars.
Idiopathic Postpartum Intussusception: A Rare Cause of Acute Abdominal Pain
Authors: Kocakoc Ercan , Bozgeyik Zulkif , Koc Mustafa , Balaban Mehtap
Published: February 2010

Objectives: To present a case with acute abdominal pain due to idiopathic intestinal intussusception diagnosed by ultrasound and computed tomography (CT) during the early postpartum period. Clinical Presentation and Intervention: A 21-year-old female patient was admitted to our hospital with abdominal pain, nausea and emesis after a normal vaginal delivery. Laboratory tests done at admission were within normal limits except for leukocytosis. Physical examination revealed abdominal distention, guarding and rebound tenderness. Abdominal ultrasound and oral contrast-enhanced CT showed a complex mass in the hypogastrium, with a typical configuration of intussusception. Emergent laparotomy revealed ileoileal invagination approximately 70 cm to the ileocecal valve but no lead point. A partial ileal resection was performed. Conclusion: This case shows that when intussusception is suspected, an abdominal ultrasound should be performed even in patients with atypical symptoms. CT may be used to confirm the diagnosis.
Asymptomatic Deep Venous Thrombosis after Deep Brain Stimulation for Parkinson Disease
Authors: Zibetti Maurizio , Rosso Mara , Cinquepalmi Annina , Lanotte Michele , Angrisano Serena , Rabbia Claudio , Valpreda Susanna , Lopiano Leonardo
Published: February 2010

Background/Aims: Patients with advanced Parkinson disease (PD) are at increased risk for asymptomatic leg deep venous thrombosis (DVT) because of severe motor fluctuations. Protracted immobility in the absence of antiparkinsonian therapy during stereotactic surgery may further increase the risk for venous thrombosis. Our aim was to determine the incidence of asymptomatic DVT of leg veins in PD patients undergoing subthalamic nucleus deep brain stimulation (STN-DBS). Methods: 41 consecutive PD patients undergoing stereotactic surgery for STN-DBS were investigated by ultrasound compression sonography of leg veins and D-dimer measurement in the week preceding surgery. After surgery, D-dimer measurements were repeated and when the value exceeded the normal range, ultrasound compression sonography was repeated to confirm or exclude DVT. Results: Doppler ultrasonographic examinations demonstrated that 2 patients (4.9%) developed asymptomatic DVT shortly after surgery (8.5 days) despite the fact that none of the 41 patients submitted to STN-DBS had DVT before surgery and that a specific prophylaxis was applied during surgery. Conclusions: Our data show that advanced PD patients are at risk for developing asymptomatic leg DVT following stereotactic surgery performed for STN-DBS. A strict clinical monitoring in the perioperative period is advisable in order to ensure early detection of DVT and prevent further thrombo-embolic complications.
Pallidotomy for Severe Tardive Jaw-Opening Dystonia
Authors: Hashimoto Takao , Naito Kosuke , Kitazawa Kazuo , Imai Sugio , Goto Tetsuya
Published: February 2010

Bilateral pallidotomy was performed in a schizophrenic patient with severe jaw-opening dystonia developed after chronic neuroleptic treatment. The dystonia led to sustained mandibular joint dislocation, and tracheotomy was performed after suffocation. The jaw-opening dystonia disappeared immediately following pallidotomy; the tracheotomy was closed, and he regained eating and speech ability. Analysis of the neuronal firing of the globus pallidus revealed low neuronal firing rates in the internal pallidum (GPi) and an irregular burst pattern of the GPi cells compared to those in Parkinson’s disease. These results suggest that pallidotomy is a treatment option for tardive jaw-opening dystonia and that dystonia of this type is driven by abnormal neural activities in the GPi.