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Biomedical subjects

J Wilkins

Publications and source records attributed to J Wilkins.

At least 145 records · Page 8Linked to original sources
PubMed1976

Emergence of resistance to amikacin during treatment of burn wounds: the role of antimicrobial susceptibility testing.

Amikacin has been used to treat Providencia stuarii infections on the Burn Service at Los Angeles County/University of Southern California Medical Center since March, 1973. The median minimal inhibitory concentration (MIC) of strains collected on this service prior to the introduction of amikacin was 3.13 mug. per milliliter, whereas the median MIC of strains collected during the last 4 months of the study was 12.5 mug per milliliter. High bactericidal concentrations (MBC) noted at the time of initial studies predicted the emergence of resistant clones, with MBV values rising to as great as 100 mu per milliliter. Further, isolates from burn patients during the initial 5 days of treatment with amikacin had a median MIC of 6925 mug per milliliter, in contrast to values of 25 mug per milliliter in strains isolated after 5 days of treatment. The epidemiologic significance of intensive treatment of gram-negative infections occurring in a close population with selected antibiotics is discussed. The performance of susceptibility tests which included determination of bactericidal concentrations was a major tool in the recognition of the potential for selection of resistant micro-organisms.

Adolescent↗
PubMed1975

Late seroconversion following HPV-77, DE5 rubella virus vaccine.

The HAI antibody responses to HPV-77, DE5 rubella virus vaccine were evaluated with respect to time in 258 rubella-susceptible children. Seroconversion after 28 days post inoculation with this vaccine was not uncommon. These findings indicate a greater degree of modification of the HPV-77, DE5 rubella virus vaccine since most vaccines have been shown to seroconvert by 28 or 30 days post inoculation with the HPV-77 and other HPV-77 derived rubella vaccines. With respect to the routine of inoculating rubella-susceptible women in the childbearing age, late seroconversion could be of importance because of this uncertainty of the time of viremia and the increased chane of pregnancy with increasing time following immunization. Comparative information is needed for the Cendehill and candidate RA 27/3 rubella virus vaccines. That vaccine showing an early and predictable higher conversion ratio would be the most desirable for use in the above population.

Antibodies, Viral↗
PubMed1975

In vitro evaluation of BL-S640, a new oral cephalosporin antibiotic.

BL-S640, a new oral cephalosporin analogue, was evaluated in vitro against 102 gram-negative and 80 gram-positive bacteria. The antimicrobial spectrum was similar to that of previous cephalosporin analogues. Good antimicrobial activity against strains of Escherichia coli, Klebsiella, staphylococci, and streptococci was demonstrated. Relatively poor activity and/or resistance was noted among most strains of Proteus, Providencia, Pseudomonas, and Serratia. In comparative studies BL-S640 had better activity against strains of Hemophilus influenzae, Staphylococcus aureus, and Enterobacteriaceae than many cephalosporin analogues. Variation of susceptibility results was dependent upon the type of media and inoculum size. Cross-resistance between BL-S640 cephalexin, cephalothin, and cefazolin was demonstrated. Among strains of Klebsiella the more rapid selection of resistance ot other cephalosporins was in contrast to BL-S640. Experience in vitro with BL-S640 has documented its antimicrobial activity,and further studies of pharmacokinetics and therapeutic efficacy are indicated.

Bacteria↗
PubMed1974

Rapid, specific microbiological assay for amikacin (BB-K8).

The emergence of a strain of Providencia stuartii resistant to multiple antibiotics with the exception of amikacin provided a test organism for a microbiological assay for this new semisynthetic aminoglycosidic aminocyclitol. Results can be read at 4 h and are specific for amikacin. The resistance of P. stuartii to all currently used antibiotics allows the utilization of this technique in the presence of other concurrently administered antibiotics and therefore eliminates the need for their inactivation in the assay procedure. The rapidity, specificity, and simplicity of this microbiological assay may provide a technique for routine clinical monitoring of patients on therapeutic regimens and could be utilized by institutions unable to perform the radioimmunoassay or radioassay techniques.

Amikacin↗
PubMed1974

Comparative in vitro evaluation of BL-P1654 and carbenicillin against Pseudomonas.

Prior investigators have reported a broad gram-negative spectrum and a marked anti-Pseudomonas activity in vitro with BL-P1654, 6-[R-alpha-(guanylureido)phenylacetamido]-penicillanic acid. An in vitro comparison of BL-P1654 to carbenicillin was performed against 84 strains of Pseudomonas and 39 strains of Enterobacteriaceae. Mean minimal inhibitory concentrations in Mueller-Hinton broth of BL-P1654 and carbenicillin were 12.5 and 100 mug/ml, respectively. Bactericidal studies with representative strains of Pseudomonas showed a consistent lack of bactericidal activity with BL-P1654. Mean bactericidal concentrations of BL-P1654 and carbenicillin were >/=200 and 100 mug/ml, respectively. The lack of bactericidal activity of BL-P1654 was further substantiated with the "killing curve" technique. Based on these data, BL-P1654 can not be considered a substitute for carbenicillin as the penicillin analogue of choice for Pseudomonas infections.

Anti-Bacterial Agents↗
PubMed1974

Phosphorylation of kanamycin, lividomycin A, amd butirosin B by Providencia stuartii.

The isolation of Providencia stuartii resistant to multiple aminoglycoside antibiotics prompted an investigation into the mechanism of their resistance. Crude enzyme extracts of a strain of P. stuartii inactivated kanamycin, lividomycin A, and butirosin B in the presence of adenosine 5'-triphosphate (ATP), as measured by a microbiological assay. The occurrence of inhibitory concentrations of 500 mug or greater per ml against kanamycin, lividomycin A, and butirosin B, coupled with the inactivation of these antibiotics in the presence of ATP, suggested enzymatic phosphorylation. This was documented by the transfer of the gamma-phosphate of [gamma-(32)P]ATP. In contrast, the inability to inactivate gentamicin or tobramycin by the crude enzyme extracts in the presence of ATP suggests another enzymatic mechanism of resistance for these antibiotics, such as adenylation or acetylation. Of importance is the fact that amikacin, a semisynthetic analogue of kanamycin A which is resistant to inactivation by most resistance transfer factor enzymes, was found to inhibit the growth of P. stuartii at low concentrations.

Aminoglycosides↗
PubMed1972

Responses of previously reinfected rubella vaccinees to challenge with Brown strain rubella virus.

The responses of seven hpv-77 rubella vaccinees to initial challenge with "wild" rubella virus have been compared with their responses to rechallenge with Brown strain rubella virus and to the responses of five "natural" immunes to initial Brown strain challenge. Previous exposure to "wild" rubella virus 220 days post vaccine-induced immunity had resulted in six of the seven vaccinees experiencing asymptomatic reinfection. On "rechallenge" none of the previously "reinfected vaccine immunes" demonstrated clinical, virologic or serologic evidence of reinfection. These data are consistent with the conclusion that persons with vaccine-induced immunity may be assured of more prolonged and solid immunity to rubella without having to suffer the clinical disease if they are reinfected with nonattenuated rubella virus. Rigidly controlled experiments, designed to study the practicality and safety of immunization with live rubella vaccine(s), followed by deliberate challenge of vaccinees with "wild" or low tissue culture passage rubella virus, seem warranted. In addition, these data indicate that it is imperative that a distinction should be made between "vaccine immunes" and previously "reinfected vaccine immunes" in any evaluation of long term rubella vaccine(s) efficacy and vaccine-induced antibody decay.

Adolescent↗
PubMed1971

The XYY syndrome in prisoners and outpatients with cystic acne.

The XYY complement appears to be more common in individuals with nodulocystic acne than in those without acne. Consequently, nodulocystic acne may prove to be a useful adjunct to height as an easily recognizable, phenotypic feature of the XYY syndrome.

Acne Vulgaris↗