bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of Amphotericin B in Fungal Culture Media
Authors: Cheung S. C. , Medoff G. , Schlessinger D. , Kobayashi G. S.
Published: June 2012

We have found that amphotericin B is unstable in two commonly employed fungal culture media. This instability leads to inaccuracies in determining the actual level of susceptibility of slow-growing strains that require prolonged incubation for growth. To help compensate for this problem, we have described two rapid methods of susceptibility testing.
Pharmacokinetics of Minocycline in Renal Failure
Authors: Welling P. G. , Shaw W. R. , Uman S. J. , Tse F. L. S. , Craig W. A.
Published: June 2012

The pharmacokinetics of minocycline have been studied after single intravenous infusions and repeated oral doses to human subjects with varying degrees of renal impairment. There was no evidence of reduced drug clearance with reduced renal function after intravenous doses although there appeared to be an increase in the tissue distribution of antibiotic in the body in uremia. After identical multiple oral dosage regimens serum levels of antibiotic were comparable in normal and mildly uremic subjects. There was no evidence of renal toxicity in normal or uremic subjects with the repeated dosage regimen used.
Minimal Inhibitory Concentration of Dapsone for
Mycobacterium leprae
in Rats
Authors: Peters J. H. , Gordon G. R. , Murray J. F. , Fieldsteel A. H. , Levy L.
Published: June 2012

To define the minimal inhibitory concentration (MIC) of dapsone (DDS) for
Mycobacterium leprae
in rats, we determined the relationship between dietary and plasma levels of DDS in uninfected male and female Lewis rats. This knowledge was applied to the design of experiments using rats inoculated in the footpads with
M. leprae
. The MIC for DDS in male and female rats, respectively, was 1.5 to 4.0 ng and 1.8 to 3.0 ng of DDS/ml of plasma, even though the sexes exhibited markedly different concentrations of DDS when receiving the same dietary level of DDS. These values for the MIC of DDS for
M. leprae
in rats are nearly identical to the previously determined MIC of DDS for
M. leprae
in mice.
In Vitro Effects of Amphotericin B on Growth and Ultrastructure of the Amoeboflagellates
Naegleria gruberi
and
Naegleria fowleri
Authors: Schuster F. L. , Rechthand Emanuel
Published: June 2012

In vitro effects of the polyene antibiotic amphotericin B (AmB) on growth, viability, and ultrastructure of amoeboflagellates of the genus
Naegleria
were examined. The strains studied were the nonpathogenic
Naegleria gruberi
EG
B
and the Carter and TY strains of the pathogenic
Naegleria fowleri
. AmB was amoebicidal at all concentrations used (0.25, 0.50, and 1.0 μg/ml) when the drug was added to cultures in lag phase, as determined by viability testing, but was mainly inhibitory when added to log-phase cultures. The drug produced ultrastructural modifications at all concentrations (0.05 to 1.0 μg/ml). These changes included distortion of nuclear shape, increase in cytoplasmic membranes (both rough and smooth endoplasmic reticulum), decrease in number of food vacuoles, absence of pseudopod formation, mitochondrial abnormalities, increase in autophagic vacuoles, and blebbing of the plasma membrane. These alterations of amoebic ultrastructure became more pronounced with increased time in AmB and with increase in AmB concentration in the growth medium.
Inactivation of the Lipid-Containing Bacteriophage PM2 by Butylated Hydroxytoluene
Authors: Cupp James , Wanda Paul , Keith Alec , Snipes Wallace
Published: June 2012

Several factors have been investigated which are of significance in the inactivation of PM2, a lipid-containing bacterial virus, by butylated hydroxytoluene (BHT). Studies of the time dependence of inactivation during exposure to BHT showed that virus killing occurs rapidly, with the majority of the effect taking place in the first 5 min. The degree of inactivation is dependent upon the initial virus titer, the solvent from which BHT is added, and the presence of a variety of protective agents, including surfactants, bovine serum albumin, and bacterial cells. Sucrose gradient analysis of
32
P-labeled, BHT-treated virus was used to determine the degree to which the virion is disrupted by BHT. These experiments show that the
32
P-labeled molecules are converted into very slowly sedimentable material by BHT treatment, indicating complete destruction of the virus particle.
Susceptibility of
Haemophilus influenzae
to Ampicillin as Determined by Use of a Modified, One-Minute Beta-Lactamase Test
Authors: Escamilla Joel
Published: June 2012

Fifty-seven cultures of
Haemophilus influenzae
were tested for production of beta-lactamase by use of a modified, 1-min test. Only the 24 cultures that were ampicillin resistant, whether type b or not, yielded positive results for the enzyme; all ampicillin-susceptible isolates were uniformly negative. The beta-lactamase procedure is simple to perform and requires only commonly available reagents.
Inhibition of
Clostridium perfringens
by an Antibiotic Substance Produced by
Bacillus licheniformis
in the Digestive Tract of Gnotobiotic Mice: Effect on Other Bacteria from the Digestive Tract
Authors: Ducluzeau R. , Dubos F. , Raibaud P. , Abrams G. D.
Published: June 2012

A strain of
Bacillus licheniformis
, established in the digestive tract of gnotobiotic mice, inhibited the subsequent establishment of a
Clostridium perfringens
strain ingested by the animals. This inhibitory effect depended on the in vivo production by
B. licheniformis
of an antibiotic substance having a number of the characteristics of bacitracin. If
C. perfringens
was the first to become established in the digestive tract of the gnotobiotic mice,
B. licheniformis
also became established but did not produce any antibiotic. Mutants of
C. perfringens
resistant to the antibiotic substance were not observed when the antibiotic was produced in situ by
B. licheniformis
, but were rapidly selected when the
Bacillus
culture filtrate or bacitracin was administered per os.
B. licheniformis
was also capable of eliminating from the digestive tract 5 of the 13 additional bacterial strains tested.
R-Factor-Mediated Resistance to Sulfonamides by a Plasmid-Borne, Drug-Resistant Dihydropteroate Synthase
Authors: Sköld Ola
Published: June 2012

Evidence was found for the existence of an episome-specified variant of the enzyme dihydropteroate synthase involved in folic acid formation. Since the plasmid-borne enzyme showed a decreased susceptibility for sulfonamide inhibition and was transferable together with resistance to this drug, it is proposed that diploidy for the target enzyme in some cases could be the mechanism of R-factor-mediated resistance to sulfonamides. Two types of evidence were obtained. One was the rescue from temperature sensitivity of bacterial mutants with a lesion in the chromosomal dihydropteroate synthase by the R factor R1
dr
19 mediating sulfonamide resistance. The other evidence was found by the determination of dihydropteroate forming activity in extracts from R
−
and R
+
bacteria. Cells harboring R1
dr
19 were found to contain an enzyme activity which was far less susceptible to sulfonamide inhibition than the corresponding activity from R
−
cells.
Clinical Pharmacology of Cefamandole as Compared with Cephalothin
Authors: Fong Ignatius W. , Ralph Edward D. , Engelking Elin R. , Kirby William M. M.
Published: June 2012

We compared the pharmacology of cefamandole and cephalothin in six healthy adult male volunteers. After a 1-g, 20-min intravenous (i.v.) infusion, the average peak blood level of cefamandole was 87.6 versus 64.1 μg/ml for cephalothin. An i.v. infusion of 500 mg/h for 2 h (after a loading dose of 750 mg) gave an average steady-state blood level of 28.5 μg/ml for cefamandole and 18.2 μg/ml for cephalothin. Mean peak serum levels after 1 g intramuscularly were similar for the two antibiotics (about 21 μg/ml), but with cefamandole they persisted longer, and the area under the blood level curve was about 25% greater. The average
t
½
as determined from both i.v. studies was 34 min for cefamandole versus 30 min for cephalothin. The mean serum clearance for cephalothin, due to its partial conversion to a metabolite, was much greater than for cefamandole (425 versus 272 ml/min per 1.73 m
2
), but the renal clearances were similar for the two antibiotics (268 versus 257 ml/min per 1.73 m
2
). Other values for cefamandole and cephalothin were: 24-h urinary excretion, 80 and 66%; serum protein binding, 74 and 70%; and apparent volume of distribution, 12.8 and 18.5 liters/1.73 m
2
, respectively. Thus, the pharmacology of the two antibiotics was similar. Blood levels were somewhat higher with cefamandole i.v., but the results suggest that dosage regimens should be the same for the two antibiotics.
Susceptibility of Ampicillin-Resistant
Haemophilus influenzae
to Seven Penicillins
Authors: Thornsberry C. , Baker C. N. , Kirven L. A. , Swenson J. M.
Published: June 2012

Sixty-seven clinical isolates of
Haemophilus influenzae
from various sections of the United States, England, and Germany were tested for susceptibility to penicillin, ampicillin, amoxicillin, epicillin, carbenicillin, ticarcillin, and methicillin. Fifty-three of the strains had previously been judged to be ampicillin resistant and 14 had been determined to be ampicillin susceptible. Fifty-two of the 53 resistant strains produced β-lactamase, but none of the susceptible strains produced it. On the basis of minimal inhibitory concentrations, the most active compounds were ticarcillin and carbenicillin. Whether this greater activity is useful clinically has not been established.
Influence of Cephalosporin Antibiotics on Blood Coagulation and Platelet Function
Authors: Natelson Ethan A. , Brown Clarence H. , Bradshaw Major W. , Alfrey Clarence P. , Williams Temple W.
Published: June 2012

Administration of cephalothin to normal volunteers in maximal doses of 300 mg/kg per day resulted in a combined defect of platelet function and blood coagulation. No such abnormalities were evident after infusion of cefazolin or cephapirin at a maximal dosage of 200 mg/kg per day. The observed thrombocytopathy was similar to but less severe than that induced by carbenicillin or ticarcillin and was not reflected by a prolonged bleeding time test or impaired prothrombin consumption. Moreover, it was not a consistent finding in those persons receiving cephalothin. A separate defect involving blood coagulation appeared to result from delayed fibrinogen-fibrin polymerization and was evidenced by extended values of the activated partial thromboplastin and thrombin time tests. It remains uncertain whether the abnormalities described may constitute clinically important hemostatic disorders in patients with normal renal function receiving large doses of cephalosporin antibiotics.
Biogenetic Origin of the
d
-Isoleucine and
N
-Methyl-
l
-Alloisoleucine Residues in the Actinomycins
Authors: Yajima Takehiko , Mason Kaarin , Katz Edward
Published: June 2012

Studies with
14
C-labeled isoleucine stereisomers have established that
l
-alloisoleucine,
d
-alloisoleucine, and
d
-isoleucine may function as precursors for the biogenesis of
d
-isoleucine and
N
-methyl-
l
-alloisoleucine residues in actinomycin.
l
-[
14
C]isoleucine appears to be employed chiefly for
d
-alloisoleucine (and
N
-methylisoleucine [?] formation); however, its role in the biosynthesis of
d
-isoleucine and
N
-methylalloisoleucine remains unclear. The potential pathway of biosynthesis of
d
-isoleucine and
N
-methyl-
l
-isoleucine is discussed.
Multiple-Aminoglycoside-Resistant Mutants of
Bacillus subtilis
Deficient in Accumulation of Kanamycin
Authors: Taber H. , Halfenger G. M.
Published: June 2012

Three classes of spontaneous multiple-aminoglycoside-resistant
(mar)
mutants of
Bacillus subtilis
were isolated by plating on a low (1.2 μg/ml) concentration of kanamycin sulfate and were found to be resistant also to low concentrations of paromomycin, neomycin and gentamicin. The three classes could be distinguished one from another by their degree of cytochrome deficiency, respiration deficiency, and susceptibility to kanamycin lethality. A fluctuation test showed that the mutations were spontaneous and not induced by the conditions of selection. Representative strains from two classes of mutants
(mar-2
and
mar-3)
accumulated aminoglycoside very poorly in comparison with the parent strain, whereas a strain of the third class
(mar-1)
inactivated aminoglycoside present in the growth medium. The
mar-3
strain studied
(aroD163)
had previously been shown to be a menaquinone auxotroph (Farrand and Taber, 1973) and to be deficient in amino acid uptake (Bisschop et al., 1975). Such mutants, which are resistant to low concentrations of aminoglycosides, may be of use in elucidating the biochemical and genetic bases of certain bacterial transport systems.
Effect of Cerulenin on Growth and Lipid Metabolism of Mycoplasmas
Authors: Rottem S. , Barile M. F.
Published: June 2012

Cerulenin markedly inhibited the growth of
Acholeplasma laidlawii. A. axanthum
and
A. granularum
were less susceptible, whereas the sterol-requiring
Mycoplasma
species examined showed very little susceptibility. The inhibition was not reversed by the addition of long-chain fatty acids to the medium. At a concentration of 20 μg/ml, cerulenin inhibited the incorporation of [
14
C]acetate into
A. laidlawii
membrane lipids, but it had no effect on either protein or nucleic acid biosynthesis. Cerulenin inhibited both the de novo synthesis of long-chain fatty acids and the elongation of medium-chain fatty acids. As a result, carotenoid biosynthesis was stimulated, and increased amounts of oleic and elaidic acids were incorporated into membrane polar lipids. Our studies support the concept that cerulenin can serve as a useful tool for obtaining better control of fatty acid composition of
A. laidlawii
membranes.
Relative Morphological Effects Induced by Cefoxitin and Other Beta-Lactam Antibiotics In Vitro
Authors: Zimmerman Sheldon B. , Stapley Edward O.
Published: June 2012

Cefoxitin, a new semisynthetic cephamycin antibiotic, induced filament formation at subinhibitory concentrations with a β-lactamaseless strain of
Enterobacter cloacae
(HSC 18410 M66). The extent of filament induction by cefoxitin was similar to that seen with cephalothin, cefazolin, and benzylpenicillin. Filament induction by cefoxitin was markedly less than that seen with cephalexin, carbenicillin, ticarcillin, cephradine, and cephapirin. Antibiotics which failed to induce filaments at any level tested included cephaloridine, cephacetrile, cephalosporin C, the cephamycins, 6-aminopenicillanic acid, 7-aminocephalosporanic acid, A16884, A16886, and FL-1060. Those antimicrobial agents tested which lacked an aromatic substituent in the 7-position (for cephems) or in the 6-position (for penams) did not induce filaments. These observations suggest a possible relationship between filament induction of the test organism and the molecular nature of constituents in the 7- or 6-position of β-lactams.
Spheroplasts of
Haemophilus influenzae
Induced by Cell Wall-Active Antibiotics and Their Effect upon the Interpretation of Susceptibility Tests
Authors: Bottone Edward J. , Brandman Zoia , Schneierson S. Stanley
Published: June 2012

The interpretation of in vitro susceptibility tests of
Haemophilus influenzae
performed by the agar or broth dilution methods with Levinthal enrichment was found to be markedly influenced by the production of spheroplasts by this species. Using an inoculum of 10
7
organisms/ml, this phenomenon was frequently evident macroscopically as a haziness on agar substrates and in broths containing cell wall-acting agents, such as ampicillin, cephalothin, and penicillin, but was not noted with chloramphenicol. Phase-contrast microscopic examination of the haze from these sources revealed numerous spherical bodies in contrast to the typical cocco-bacillary forms observed in growth controls. With this inoculum size, minimal bactericidal concentrations could not be determined since subculture of 0.1 ml of the hazy broths or the surface haze onto chocolate agar resulted in most instances in the development of a small number of colonies which, upon smear and gram stain, revealed typical
Haemophilus
morphology. An inoculum of 10
4
organisms/ml abolished the haziness on agar surfaces and in broths and resulted in clear-cut end points. Also, although spherical bodies were still present, they were distinctly less in number as contrasted to tests performed with an inoculum of 10
7
organisms/ml. It is recommended that minimal inhibitory concentration end points in antibiotic susceptibility tests be determined by microscopic, rather than macroscopic, observation of the growth milieu to determine the presence or absence of morphologically typical bacilli which, when observed, is indicative of true in vitro resistance.
Evaluation of Antibiotic Efficacy Using Electron Microscopy: Morphological Effects of Guanylureido Cephalosporin, Chlorobenzoylureido Cephalosporin, BL-P1654, and Carbenicillin on
Pseudomonas aeruginosa
Authors: Ellis L. F. , Herron D. K. , Preston D. A. , Simmons L. K. , Schlegel R. A.
Published: June 2012

The response of
Pseudomonas aeruginosa
to carbenicillin, BL-P1654, and two cephalosporins (112384 and 112883) was evaluated by minimal inhibitory concentration determinations, [
14
C]leucine uptake studies, morphological studies of colonial growth, and mouse intraperitoneal inoculations. Spheroplast formation and bacterial lysis were not the early response; instead, cell division was inhibited and long filaments were formed. Spheroplast formation and bacterial lysis were not observed in the first 7 h of incubation in minimal inhibitory concentrations of antibiotic.
Mode of Action In Vitro Against Mengovirus of Substituted 5-Amino-4-Cyanopyrazoles
Authors: Tonew Marion , Lippmann Elisabeth , Willitzer H.
Published: June 2012

Substituted amino pyrazoles were found to exhibit plaque reduction and inhibition of the cytopathic effect of mengovirus on FL cells. Their antiviral activity was not caused by a virucidal effect or by inhibition of viral adsoprtion or penetration but by suppression of the virus multiplication. During a one-step growth cycle maximum suppression of virus yield occurred after compound addition from 0 to 2 h after infection. Progressively less viral inhibition appeared when compound was applied during the later part of virus replication. The antiviral effect was reversible by removal of the compound, and no inhibitor-resistant period occurred.
Cefuroxime, a New Cephalosporin Antibiotic: Activity In Vitro
Authors: O'Callaghan Cynthia H. , Sykes R. B. , Griffiths A. , Thornton J. E.
Published: June 2012

Cefuroxime is a new broad-spectrum cephalosporin antibiotic with increased stability to β-lactamases. This stability, although no absolute in all cases, has the effect of widening the antibacterial spectrum of the compound so that many organisms resistant to the established cephalosporins are susceptible to cefuroxime. It is active against gram-positive organisms, including penicillinase-producing staphylococci, but it is less active against methicillin-resistant strains. In addition to its high activity against non-β-lactamase-producing gram-negative bacteria, cefuroxime effectively inhibits the growth of many β-lactamase-producing strains, including
Enterobacter, Klebsiella
, and indole-positive
Proteus
spp. It is highly active against
Neisseria gonorrhoeae, Neisseria meningitidis
, and also
Haemophilus influenzae
, including ampicillin-resistant strains. Cefuroxime is rapidly bactericidal and induces the formation and subsequent lysis of filamentous forms over a small concentration range.
In Vitro Susceptibility Studies with Josamycin and Erythromycin
Authors: Strausbaugh Larry J. , Dilworth John A. , Gwaltney Jack M. , Sande Merle A.
Published: June 2012

The in vitro activity of josamycin and erythromycin against five bacterial species was compared. In general, erythromycin was slightly more active by weight than josamycin, although both agents had a similar range of activity.
Significant Reduction in the Incidence of Phlebitis with Buffered Versus Unbuffered Cephalothin
Authors: Bergeron Michel G. , Brusch John L. , Barza Michael , Weinstein Louis
Published: June 2012

Cephalothin (1 g every 2 h), buffered cephalothin, and diluent alone (5% dextrose in water) were each administered for 4 days intravenously to 12 volunteers in a double-blind crossover study. The incidence of phlebitis with buffered cephalothin was significantly lower than that with unbuffered drug (
P
< 0.01) and almost identical to the incidence with diluent alone.
Effect of Diethylpyrocarbonate on the Antiviral and Interferon-Inducing Activities of Viral and Nonviral Agents
Authors: Yamamura Yasuhiro , Cochran Kenneth W.
Published: June 2012

Diethylpyrocarbonate (DEPC) treatment of interferon (IF) inducers was studied both in vitro and in vivo. DEPC did not affect the antiviral activity of poly(I·C), statolon, or reovirus in cultured chicken embryo fibroblast cells, but the activities of poly(I·C), statolon, and MU9 replicative form in cultured mouse embryo cells were markedly reduced by the treatment. Target-organ treatment of Swiss Webster mice with DEPC-treated poly(I·C) produced higher levels of serum IF than did the same procedure with untreated poly(I·C), but the animals were not protected against vaccinial encephalitis. In contrast, DEPC-treated statolon protected the animals, although the peak serum IF level was significantly lower than in those treated with intact statolon. Nevertheless, the antiviral activity of statolon was also found to be mediated by IF, since no activity was seen in Vero cells. DEPC-treated single-stranded ribonucleic acid viruses failed to stimulate IF production, indicating that some viral factor(s) susceptible to DEPC is required for the stimulation observed with untreated viruses.
Nephrotoxicity of Cephalosporin-Gentamicin Combinations in Rats
Authors: Luft Friedrich C. , Patel Vimal , Yum Moo Nahm , Kleit Stuart A.
Published: June 2012

To study the possibility that cephalosporins augment the nephrotoxicity of gentamicin, groups of rats were given four hourly subcutaneous doses of: gentamicin (5 mg/kg), gentamicin plus cephalothin (100 mg/kg), gentamicin plus cefazolin (20 mg/kg), gentamicin plus cefazolin (50 mg/kg), gentamicin plus cephaloridine (50 mg/kg), or saline diluent for 15 days. Periodic measurements were made of urine volume, urine osmolality, urine protein excretion and lysosomal enzymuria, as well as blood urea nitrogen, creatinine clearance, and drug concentrations in renal cortex and medulla. Tissue was examined by light and electron microscopy. Enzymuria and proteinuria increased early in the course of all treatment groups, whereas urine osmolality declined. No distinct patterns of these variables were discernable among the groups. Gentamicin alone, gentamicin plus cephalothin, and gentamicin plus cefazolin (20 mg/kg) caused the same significant fall in glomerular filtrate rate from control values by day 15 (
P
< 0.05). Gentamicin plus cefazolin (50 mg/kg) and gentamicin plus cephaloridine failed to cause a decline in glomerular filtration rate compared with controls (
P
> 0.05). Gentamicin concentrations in renal cortex were 5 to 10 times higher than those in medulla in all groups. Cephaloridine and cefazolin (50 mg/kg) also displayed a gradient pattern in renal cortex, whereas cephalothin and cefazolin (20 mg/kg) did not. Cytosegrosomes with myeloid figures were characteristic ultra-structural changes seen in all groups; however, they tended to be smaller with less numerous myeloid bodies in the groups receiving gentamicin plus cephalothin, cefazolin (50 mg/kg), or cephaloridine. Cephalosporins did not augment gentamicin toxicity. High doses of cefazolin and cephaloridine protected kidneys from gentamicin nephrotoxicity. The protection may involve intracellular drug interaction within the renal cortex.
Inactivation of Gentamicin by Penicillins in Patients with Renal Failure
Authors: Ervin F. Richard , Bullock Ward E. , Nuttall Charles E.
Published: June 2012

Kinetics of gentamicin inactivation by carbenicillin and ticarcillin were studied in vitro and in 17 patients with renal failure. In vitro, the half-life of carbenicillin in human serum at 37 C is longer (19.2 ± 0.7 h) than ticarcillin (7.2 ± 0.6 h). Thus, incubation of gentamicin with equal concentrations of ticarcillin or carbenicillin results in greater inactivation of aminoglycoside activity by the latter. If concentrations of the two penicillins are held equal by repetitive addition, rates of gentamicin inactivation are the same.

The serum half-life of gentamicin in patients serving as their own controls was significantly reduced by administration of either penicillin. After carbenicillin, the half-life decreased from 46 ± 8 h to 22 ± 3 h (
P
< 0.02). The constant for inactivation of gentamicin (

k
i

) by carbenicillin was 0.02 h
−1
. The results indicate that gentamicin requirements are underestimated by methods currently employed to calculate dosage for patients with renal failure who receive carbenicillin concurrently. Adjustment of gentamicin dosage in such cases by application of the

k
i

for gentamicin is suggested.
Susceptibility of
Enterobacter
to Cefamandole: Evidence for a High Mutation Rate to Resistance
Authors: Findell C. M. , Sherris J. C.
Published: June 2012

Cefamandole minimum inhibitory concentrations (MICs) of 10 strains of
Enterobacter
were determined by the ICS agar dilution and broth dilution procedures. Agar dilution MICs ranged from 1 to 8 μg/ml, with an inoculum of 10
4
organisms/spot. Broth dilution MICs were consistently higher, with an inoculum of approximately 7 × 10
5
organisms/ml. Seven strains showed MICs of ≥64 μg/ml. There was a marked inoculum effect in broth, and skipped tubes were often observed. Variants resistant to 32 μg/ml or more were isolated by direct selection and were shown to occur at a frequency of approximately 10
−6
to 10
−7
. A mutant showing a 16-fold increase in agar dilution MIC was also isolated by indirect selection. These variants and others isolated from broth in the presence of cefamandole were tested for ability to inactivate the antibiotic, using both a biological and a chemical procedure. Two distinct classes of variants were seen. Twelve of 28 were shown by both methods to inactivate the antibiotic, whereas the others, including the indirectly selected mutant, did not. The wild types were also negative by both tests. The higher cefamandole MICs of
Enterobacter
in broth, thus, appeared to reflect a high frequency of resistant variants that were not detected with the inoculum and end point criteria usually used in agar dilution methods. The ability of some variants to inactivate cefamandole may have resulted from a mutation that extended the activity of
Enterobacter
cephalosporinase to include this antibiotic.
Genome Sequence of the Shiga Toxin-Producing Escherichia coli Strain NCCP15657
Authors: Kim Byung Kwon , Song Geun Cheol , Hong Gun Hyong , Seong Won-Keun , Kim Seon-Young , Jeong Haeyoung , Kang Sung Gyun , Kwon Soon-Kyeong , Lee Choong Hoon , Song Ju Yeon , Yu Dong Su , Park Mi-Sun , Cho Seung-Hak , Kim Jihyun F.
Published: June 2012

Shiga toxin-producing
Escherichia coli
causes bloody diarrhea and hemolytic-uremic syndrome and serious outbreaks worldwide. Here, we report the draft genome sequence of
E. coli
NCCP15657 isolated from a patient. The genome has virulence genes, many in the locus of enterocyte effacement (LEE) island, encoding a metalloprotease, the Shiga toxin, and constituents of type III secretion.
Genome Sequence of an Oligohaline Hyperthermophilic Archaeon, Thermococcus zilligii AN1, Isolated from a Terrestrial Geothermal Freshwater Spring
Authors: Kim Byung Kwon , Lee Seong Hyuk , Kim Seon-Young , Jeong Haeyoung , Kwon Soon-Kyeong , Lee Choong Hoon , Song Ju Yeon , Yu Dong Su , Kang Sung Gyun , Kim Jihyun F.
Published: June 2012

Thermococcus zilligii
, a thermophilic anaerobe in freshwater, is useful for physiological research and biotechnological applications. Here we report the high-quality draft genome sequence of
T. zilligii
AN1
T
. The genome contains a number of genes for an immune system and adaptation to a microbial biomass-rich environment as well as hydrogenase genes.
Genome Sequence of the Unclassified Marine Gammaproteobacterium BDW918
Authors: Kim Suk Min , Cho Sun Ja , Lee Sun Bok
Published: June 2012

The unclassified marine gammaproteobacterium BDW918, which utilizes volatile fatty acids but not most common carbohydrates and amino acids, was isolated from Dokdo seawater in South Korea. Here we present a draft genome of the strain BDW918, which encodes many putative genes related to fatty acid metabolism and aromatic hydrocarbon degradation.
In vitro and in silico study of intracranial stent treatments for cerebral aneurysms: effects on perforating vessel flows
Authors: Roszelle Breigh Nonte , Babiker M Haithem , Hafner Walter , Gonzalez L Fernando , Albuquerque Felipe C , Frakes David H
Published: June 2012

Background

Many cerebral aneurysms can be treated effectively with intracranial stents. Unfortunately, stents can occlude perforating vessels near the treatment site which can decrease cerebral perfusion and increase the risk of stroke.

Methods

Particle image velocimetry was used to investigate the effects of intracranial stents on flows in perforators near a treated aneurysm. In Phase 1 of the study, different stent configurations were deployed into an idealized physical model of a sidewall aneurysm with perforating vessels. The configurations investigated were the Pipeline embolization device (PED) and one, two and three telescoping Neuroform stents. In Phase 2 of the study a single Neuroform stent was deployed so that the stent struts directly occluded the perforating vessel.

Results

In Phase 1 of the study it was found that even three telescoping stents affected perforating vessel flow less than a single PED under pulsatile conditions (average reduction 32.7% vs 46.5%). Results from Phase 2 indicated that the location of the occluding strut across the perforating vessel orifice had a greater impact on perforating vessel flow than the percentage occlusion.

Conclusion

The findings of this study show that the use, configuration and positioning of intracranial stents can all have considerable influence on flow in affected perforating vessels near treated cerebral aneurysms.
Induction of antimicrobial peptides fromRana dybowskiiunder Rana grylio virus stress, and bioactivity analysis
Authors: Yang Shu-Jing , Xiao Xiang-Hong , Xu Yi-Gang , Li Dan-Dan , Chai Long-Hui , Zhang Jing-Yu
Published: June 2012

The skin glands of Ranidae are a rich source of antimicrobial peptides. In this study, the genomic RNA of Rana dybowskii was extracted from its skin while under Rana grylio virus stress. Five new cDNA sequences encoding 5 mature peptides, Ranatuerin-2YJ (GLMDIFKVAVNKLLAAGMNKPRCKAAHC), Dybowskin-YJb (IIPLPLGYFAKKP), Dybowskin-YJa (IIPLPLGYFAKKKKKKDPVPLDQ), Temperin-YJa (VLPLLETCSMTCWENNQTFGK), and Temperin-YJb (VLPLVGNLLNDLLGK), were obtained by reverse transcription polymerase chain reaction with a pair of degenerate primers designed according to the conserved terminal sequences of cDNA encoding antimicrobial peptide precursors of genus Rana. The antimicrobial activities of the peptides were analyzed, and the results demonstrated that all these peptides showed a significant anti-Rana grylio virus activity, and the virus was gradually cleared with the increase in gene expression. Among the 5 peptides obtained in this work, Ranatuerin-2YJ also showed a broad-spectrum anti-Gram-positive bacteria and anti-Gram-negative bacteria activity with a minimal inhibitory concentration of 22.5 µg/mL and 7.64% hemolysis activity, both of which were significantly lower (p < 0.05) than that of the other peptides. Moreover, Ranatuerin-2YJ was widely distributed in the skin, liver, spleen, and blood of R. dybowskii, while the other 4 peptides could only be cloned from the skin, indicating that the Ranatuerin-2YJ in vivo plays an important role in the protection against pathogen invasion.
Preventing Ralstonia solanacearum adhesion with glycans from cashew, cocoa, coffee, pumpkin, and tomato seed extract
Authors: Rachmaninov Ofra , Zinger-Yosovich Keren D. , Gilboa-Garber Nechama
Published: June 2012

Ralstonia solanacearum wilts many plants, causing heavy agricultural losses. Its pathogenic strain ATCC 11696 produces 2 hemagglutinating lectins: RSL and RS-IIL. These lectins may bind to terminal l-fucose-, d-arabinose-, and d-mannose-bearing seedling xylem cell wall glycans, thus enabling pathogen adhesion to them, with devastating infection establishment. Blocking the active sites of these lectins with seed embryo-surrounding oligo- and poly-saccharides hampers binding of the lectins to the embryos. The current study shows that seeds of cashew, cocoa, coffee, pumpkin, and tomato contain low and high molecular mass glycans that block RSL and RS-IIL (like its homologous Pseudomonas aeruginosa PA-IIL lectin). The blocking of the pathogen lectins, which is attributable to the documented composition of the oligo- and poly-saccharides of these seeds, is similar to that observed with animal glycoproteins of avian egg whites (protecting their embryos from infections) and of milk and royal jelly, which likewise protect mammal and bee neonates, respectively. RSL was most strongly inhibited by cashew seed glycans, and RS-IIL by coffee seed glycans. Western blot analyses with these lectins instead of antibodies revealed the hitherto undescribed presence of lectin-binding glycoproteins in the coffee, pumpkin, tomato, and cashew (but not cocoa) seeds. The use of these lectins for unveiling potent embryo-protecting seed glycans might be helpful for seedling-bioprotection projects similar to those planned for animal protection against antibiotic-resistant infections.
Characterization of 4 T1-like lytic bacteriophages that lyse Shiga-toxin Escherichia coli O157:H7
Authors: Niu Yan D. , Stanford Kim , Ackermann Hans-W. , McAllister Tim A.
Published: June 2012

Bacteriophages are associated with reduced fecal shedding of Shiga-toxin-producing Escherichia coli O157:H7 (STEC O157:H7) in cattle. Four phages exhibiting activity against 12 of 14 STEC O157:H7 strains, representing 11 common phage types, were isolated. Phages did not lyse non-O157 E. coli, with 11 of the 12 STEC strains exhibiting extreme susceptibility (average multiplicity of infection (MOI) = 0.0003−0.0007). All phages had icosahedral heads with tapered, noncontractile tails, a morphology indicative of T1-like Siphoviridae. Genome size of all phages was ∼44 kb, but EcoRІ or HindIII digestion profiles differed among phages. Based on restriction enzyme digestion profiles, phages AHP24, AHS24, and AHP42 were more related (66.7%−82.4%) to each other than to AKS96, while AHP24 and AHS24, isolated from the same feedlot pen, exhibited the highest identity (88.9%−92.3%). Phages AHP24 and AHS24 exhibited the broadest host range and strongest lytic activity against STEC O157:H7, making them strong candidates for biocontrol of this bacterium in cattle.
INVESTIGATION OF TRANSPORT AND OPTICAL PROPERTIES OF MESOPOROUS ANATASE AND RUTILE TiO2 FILMS FOR APPLICATION IN DYE-SENSITIZED SOLAR CELLS
Authors: JYOTI DIVYA , MOHAN DEVENDRA , DHAR RAKESH
Published: June 2012

The transport of electrons through TiO 2 anatase and rutile thin films synthesized via sol–gel route has been investigated using electronic and optical spectroscopic studies. Mesoporosity of the films is confirmed by poroellipsometry. A smaller electron effective mass in anatase can be accounted for larger effective Bohr radius of trap electrons observed in anatase than in rutile. Further, the smaller effective mass in anatase favors high mobility. A mott transition is observed in anatase with change in temperature but not in rutile. Luminescence of self-trapped excitons is observed in anatase thin films, that implies a strong lattice relaxation.
A MATHEMATICAL MODEL FOR CELL-INDUCED GEL COMPACTION IN VITRO
Authors: GREEN J. E. F. , BASSOM ANDREW P. , FRIEDMAN AVNER
Published: June 2012

We present a mathematical model for cell-induced gel contraction in vitro. The core of the model consists of conservation equations for the mass of the gel and the number of cells, coupled to a force balance on the gel. On the basis of previously reported experimental findings for collagen gels, which are frequently used experimentally, the gel is treated as a compressible viscous fluid while inertial effects are neglected. The flow is assumed to be isothermal, and a linear pressure–density relation is adopted. The force exerted on the gel by cells is assumed to depend upon the local environment surrounding the cell: influences can include the cell and extracellular matrix density, and the concentration of a diffusible chemical produced by the cells. We consider the simple, but experimentally relevant, case of spherically symmetric gels. For cell-free gels, we show how simple experiments might be used to determine the parameters in the model. When the cell-derived forces are given by a prescribed function of position, we are able to obtain the early time and steady-state behavior of the solution analytically. We perform numerical simulations which generate predictions of how the gel density evolves during compaction under differing assumptions concerning the factors influencing the force exerted by the cells. These results are compared with some previous observations reported in the literature.
DECAY RATES TO VISCOUS CONTACT WAVES FOR A 1D COMPRESSIBLE RADIATION HYDRODYNAMICS MODEL
Authors: ROHDE CHRISTIAN , XIE FENG
Published: June 2012

We are concerned with the nonlinear stability of contact waves subject to general perturbations of initial datum in the Cauchy problem for a radiating gas model. The model is represented mathematically as a one-dimensional hyperbolic–elliptic system. It is known that general perturbations of contact discontinuities may generate diffusion waves which evolve and interact with the contact wave. In order to quantify the decay to the contact waves exactly, we need to construct the corresponding diffusion waves explicitly depending on the perturbation of the initial datum. Then, the constructed diffusion waves can be added to the viscous contact wave to form a new combined wave pattern. In this paper, we will show that the new combined wave pattern is nonlinear stable provided that the general perturbation of the initial datum and the strength of the contact wave are suitably small. In particular we give detailed convergence rates using anti-derivative methods and elaborated energy estimates. The work extends the results of Huang, Xin and Yang in [Contact discontinuity with general perturbations for gas motions, Adv. Math. 219 (2008) 1246–1297] for compressible Navier–Stokes equations to a system with much weaker dissipation mechanism.
REDUCIBILITY OF THE COHEN–WALES REPRESENTATION OF THE ARTIN GROUP OF TYPE Dn
Authors: LEVAILLANT CLAIRE
Published: June 2012

We construct a linear representation of the CGW algebra of type Dn. This representation has degree n2 - n, the number of positive roots of a root system of type Dn. We show that the representation is generically irreducible, but that when the parameters of the algebra are related in a certain way, it becomes reducible. As a representation of the Artin group of type Dn, this representation is equivalent to the faithful linear representation of Cohen–Wales. We give a reducibility criterion for this representation as well as a conjecture on the semisimplicity of the CGW algebra of type Dn. Our proof is computer-assisted using Mathematica.
ASSISTIVE VIBROTACTILE BIOFEEDBACK SYSTEM FOR POSTURAL CONTROL ON PERTURBED SURFACE
Authors: GOPALAI ALPHA AGAPE , SENANAYAKE S. M. N. AROSHA
Published: June 2012

Postural control is an important aspect of human locomotion and stance. When inputs to the Central Nervous System (CNS), consisting of the vestibular, somatosensory, and visual senses, degrade or become dysfunctional, the postural control is affected. Biofeedback has been established as a potential intervention method to assist individuals improve postural control, by augmenting or complementing signals to the CNS. This paper presents an approach to help achieve better postural control using vibrotactile biofeedback. Tests to monitor postural control, in eyes open and eyes closed states, on a wobble board were introduced to assess the viability of the designed system in providing accurate real-time biofeedback responses. Postural control was gauged by measuring the angular displacement of perturbations experienced. Perturbations along the anterior and posterior direction are used to determine the level of provided vibrotactile biofeedback. The feedback informs subjects the severity of perturbation and direction of imbalance. Significant improvement (p-value < 0.05) in postural control while on perturbed surface was detected when the designed biofeedback system was used. The wearable system was found to be effective in improving postural control of the subjects and can be expanded for rehabilitation, conditioning, and strengthening applications dealing with human postural control.
PROBABILISTIC TSUNAMI HAZARD ANALYSIS AND RISK TO COASTAL POPULATIONS IN THAILAND
Authors: SUPPASRI ANAWAT , IMAMURA FUMIHIKO , KOSHIMURA SHUNICHI
Published: June 2012

The study of tsunami hazards in Thailand has been an ongoing topic of research. However, the hazards from tsunami sources based on probabilistic study and population risk are still unclear. In this study, potential tsunami sources along rupture zones were selected. A series of far-field tsunami simulations were performed with scaled fault parameters based on fault lengths from 100–600 km. The results show that within a few centuries, the maximum tsunami height could be 2–5 m at the west coast and less than 2 m at the east coast. The potential tsunami exposure (PTE) of populations in an estimated inundation zone was calculated using global population data in relation to tsunami height. The results show that much attention should be paid to fault ruptures longer than 300 km (≈ 8.5 moment magnitude, Mw) that originate from 4°–6° N and 14°–17° N for the Sumatra subduction zone and the Manila trench, respectively. A quarter of a million people are at risk of exposure to a maximum 9 m tsunami height after 100 min of the arrival of the first wave at the Andaman coast. One million people near the Gulf of Thailand are at risk of a tsunami height less than 3 m after 9 hr.
Implantable Closed-Loop Epilepsy Prosthesis
Authors: Salam Muhammad Tariqus , Sawan Mohamad , Nguyen Dang Khoa
Published: June 2012

In this article, we present an implantable closed-loop epilepsy prosthesis, which is dedicated to automatically detect seizure onsets based on intracerebral electroencephalographic (icEEG) recordings from intracranial electrode contacts and provide an electrical stimulation feedback to the same contacts in order to disrupt these seizures. A novel epileptic seizure detector and a dedicated electrical stimulator were assembled together with common recording electrodes to complete the proposed prosthesis. The seizure detector was implemented in CMOS 0.18-
μ
m by incorporating a new seizure detection algorithm that models time-amplitude and -frequency relationship in icEEG. The detector was validated offline on ten patients with refractory epilepsy and showed excellent performance for early detection of seizures. The electrical stimulator, used for suppressing the developing seizure, is composed of two biphasic channels and was assembled with embedded FPGA in a miniature PCB. The stimulator efficiency was evaluated on cadaveric animal brain tissue in an in vitro morphologic electrical model. Spatial characteristics of the voltage distribution in cortex were assessed in an attempt to identify optimal stimulation parameters required to affect the suspected epileptic focus. The experimental results suggest that lower frequency stimulation parameters cause significant amount of shunting of current through the cerebrospinal fluid; however higher frequency stimulation parameters produce effective spatial voltage distribution with lower stimulation charge.
Hyperglycemia Induces the Variations of 11β-Hydroxysteroid Dehydrogenase Type 1 and Peroxisome Proliferator-Activated Receptor-γExpression in Hippocampus and Hypothalamus of Diabetic Rats
Authors: Qi Wen-wen , Zhong Li-yong , Li Xiao-rong , Li Guang , Liu Zhao-xia , Hu Jin-feng , Chen Nai-hong
Published: June 2012

In this paper, we first observed that there were differences in expressions of 11β-HSD1 and PPAR-γ, in hippocampi and hypothalami, among constant hyperglycemia group, control group and the fluctuant glycemia group, using Immunohistochemical analysis. However, whether in expression o f 11β-HSD1 or PPAR-γ, there were no statistic differences between the control group or the fluctuant glycemia group. So, we removed the fluctuant glycemia group, retaining only constant hyperglycemia group and control group, being fed for 8 weeks. After 8 weeks of induction, 11β-HSD1 expression increased and PPAR-γexpression decreased in the constant hyperglycemia group compared with control group, both in hippocampi and hypothalami, by Western Blot. The constant hyperglycemia group also showed impaired cognition in MORRIS watermaze, lower serum corticosterone level, and higher Serum ACTH concentration after 8 weeks. We inferred that the cognition impairment may be related to the abnormal expression of 11β-HSD1 and PPAR-γin central nerves system. As for 11β-HSD1 is a regulating enzyme, converting the inactive 11-dehydrocorticosterone into the active glucocorticoid corticosterone, thus amplifying GC action in local tissues. It is also well known that high local GC levels can affect the cognitive function. In addition, PPAR-a protective receptor, which is related to cognition.
Focus on Brain Angiotensin III and Aminopeptidase A in the Control of Hypertension
Authors: Wright John W. , Mizutani Shigehiko , Harding Joseph W.
Published: June 2012

The classic renin-angiotensin system (RAS) was initially described as a hormone system designed to mediate cardiovascular and body water regulation. The discovery of a brain RAS composed of the necessary functional components (angiotensinogen, peptidases, angiotensins, and specific receptor proteins) independent of the peripheral system significantly expanded the possible physiological and pharmacological functions of this system. This paper first describes the enzymatic pathways resulting in active angiotensin ligands and their interaction with AT1, AT2, and mas receptor subtypes. Recent evidence points to important contributions by brain angiotensin III (AngIII) and aminopeptidases A (APA) and N (APN) in sustaining hypertension. Next, we discuss current approaches to the treatment of hypertension followed by novel strategies that focus on limiting the binding of AngII and AngIII to the AT1receptor subtype by influencing the activity of APA and APN. We conclude with thoughts concerning future treatment approaches to controlling hypertension and hypotension.
The Asymptotic Solution of the Initial Boundary Value Problem to a Generalized Boussinesq Equation
Authors: Yin Zheng , Zhang Feng
Published: June 2012

The L2 space solution of an initial boundary problem for a generalized
damped Boussinesq equation is constructed. Certain assumptions on the coefficients of
the equation are found to show the existence and uniqueness of the global solution to the
initial boundary problem. The explicit expression for the large time asymptotic solution is
obtained.