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Biomedical subjects

R Aly

Publications and source records attributed to R Aly.

86 records · Page 5Linked to original sources

Correlation of human in vivo and in vitro cutaneous antimicrobial factors.

the presence of antimicrobial substances on human skin was investigated. Staphyloccus aureus (10-4 colony-forming units) was applied on the forearm of 50 subjects and covered with a semiocclusive device for 24 hr. In 54% of the subjects the organisms persisted, and in 34% S. aureus was inhibited on the skin. Subjects with persistent S. aureus also had persistent Candida albicans, and vice persa. This correlation was not noted with Streptococcus pyogenes. Skin lipids from the two groups of subjects were extracted with acetone and assayed against S. aureus, S. pyogenes, and C. albicans. The percentage of S. aureus or C. albicans recovered was higher (79% and 55%, respectively) in subjects with persistent microrgamisms on their skin than in those without (47% and 28%, respectively). Subjects with persistent S. aureus and C. albicans had higher counts of normal flora (average, 9.2 times 10-3) than those on whose skin these organisms did not persist (average, 7.4 times 10-2). Coagulase-negative Staphylococcus and Micrococcus were found in higher proportions in subjects with persistent test organisms than in those without. Subjects with lower counts of their normal flora had a higher proportion of diphtheroids (34%) than the high-count group (12%).

Acetone↗

A simple single-step immunoimmobilisation method for the detection of Salmonella in the presence of large numbers of other bacteria.

A single-step disk immunoimmobilisation method for the detection of motile salmonellae is described. It combines in a single step the use of the motility of these bacteria in soft agar, their selective growth on Salmonella-Shigella media, and their immobilisation by polyvalent H antiserum. The method is shown to be 10 to 10,000 times more senstitive than a standard method for detection of Salmonella under the experimental conditons used. The time required for detection is shortened to 24-48 h.

Agar↗

Protection of chicken embryos by viridans streptococci against the lethal effect of Staphylococcus aureus.

Chicken embryos were used to investigate the mechanism by which viridans streptococci inhibit the growth of pathogenic staphylococci. Ten-day-old embryonated eggs were infected allantoically. At a concentration of 1.8 x 10(2) colony-forming units (CFU) of viridans streptococci, the percentage of fatalities was less than 10%. There was 80% fatality with 8 x 10(1) CFU of Staphylococcus aureus strain 502A and 100% when a 100-fold increase in concentration was used. An inoculum size of 10(2) to 10(3) CFU of viridans streptococci was chosen to protect the embryos against the lethal effect of strain 502A when challenged 24 h later. The survival after challenging at 4 days was 93% in protected eggs and 37% in unprotected eggs. Chicken embryos receiving heat-killed viridans and challenged with strain 502A when examined after 4 days did not demonstrate a protective effect. This protection of embryonated eggs could not be transferred by administration of sterile filtrate of allantoic fluid in which protecting strain was grown. The experimental infection of embryonated eggs has demonstrated that prior allantoic infection with viridans streptococci affords significant protection against subsequent challenge with virulent staphylococci.

Animals↗

Effects of a systemic antibiotic on nasal bacterial ecology in man.

The nasal flora of coagulase-positive staphylococcus carriers and noncarriers was studied in aerobic conditions in 17 individuals. Five hundred milligrams of cephalexin was given orally four times daily for 12 days, and its effects on the nasal bacteria were determined quantitatively before, during, and after treatment. The total count obtained before the drug treatment was 5.4 x 10(6) in carriers and 3.9 x 10(6) in noncarriers. The lowest total count observed was 3 days after the cessation of the drug. The increase in gram-negative rods was seen 9 days after antibiotic therapy, not during the greatest reduction of gram-positive bacteria. Coagulase-positive cocci and diphtheroids were most sensitive to drug treatment. After 36 days, the total count was restored to pretreatment level. Diphtheroids did not return to the original number and were replaced by a corresponding increase of resistant coagulase-negative cocci. An inverse relationship between coagulase-negative cocci and lipophilic diphtheroids was seen in the anterior nares of many individuals. No gross difference in nasal ecology to differentiate carriers from noncarriers was seen.

Administration, Oral↗

Effects of breathable disposable diapers: reduced prevalence of Candida and common diaper dermatitis.

Infants wearing breathable disposable diapers experienced significantly less diaper dermatitis (DD) compared to infants wearing standard, nonbreathable disposable diapers in a series of double-blind clinical trials. Severe DD, including confirmed infection with Candida albicans, was reduced by 38-50% among infants wearing highly breathable (HB) diapers. The prevalence of DD was inversely related to the breathability of the garments. The inhibitory effect of breathable diapers on the survival of Candida was further confirmed in controlled experiments with adult volunteers. A suspension of C. albicans cells was applied to delineated sites on the volar forearm. Each site was then covered by a full-thickness patch from either an HB or a standard diaper. Survival of Candida colonies was reduced by almost two-thirds in the breathable diaper-covered sites compared to the control sites.

Candidiasis↗

Trichophyton tonsurans tinea capitis in the San Francisco Bay area: increased infection demonstrated in a 20-year survey of fungal infections from 1974 to 1994.

Tinea capitis caused by Trichophyton tonsurans has been increasing in the United States for the past 25 years. A retrospective study of dermatophyte culture data at the University of California, San Francisco, and a parallel study of patient visits for tinea capitis at an affiliated hospital demonstrates a dramatic rise in Trichophyton tonsurans tinea capitis in the San Francisco Bay area.

Humans↗

Adherence of Staphylococcus aureus to squamous epithelium: role of fibronectin and teichoic acid.

For bacteria to colonize mucosal surfaces, they must be able to attach to epithelial cells. One of the most important factors in determining this attachment is bacterial adherence. The preferential adherence of a bacteria to a particular tissue influences the site of infection and the virulence of the organism. The glycoprotein fibronectin mediates adhesion of the bacteria to eukaryotic cells. Recent investigations have revealed that the precise locations of the binding sites for Staphylococcus aureus are close to the NH2-terminal and at the COOH-terminal regions of the fibronectin molecule. Teichoic acids are major cell-wall components of staphylococci that have been found to mediate the capacity of the bacteria to adhere to epithelial cells. By use of biologic assays based on the specific adherence of S. aureus to nasal epithelium, it was determined that the binding site for fibronectin appears to be teichoic acid.

Animals↗

Ciclopirox olamine lotion 1%: bioequivalence to ciclopirox olamine cream 1% and clinical efficacy in tinea pedis.

Studies were conducted to assess the bioequivalence of a new antimycotic formulation, ciclopirox olamine lotion 1%, to an established compound, ciclopirox olamine cream 1%. Results of in vitro studies, using skin samples from human cadavers and domestic pigs, demonstrated that the two formulations equally penetrate all layers of the stratum corneum and inhibit the growth of Trichophyton mentagrophytes and Candida albicans. In vivo studies in guinea pigs and in human volunteers demonstrated the comparable therapeutic efficacy of the lotion and the cream in experimental trichophytosis. In addition, a multicenter, double-blind clinical trial was undertaken to compare ciclopirox olamine lotion 1% with the vehicle alone in the treatment of patients with tinea pedis. Patients with plantar, interdigital, or vesicular tinea pedis were enrolled in the studies. Patients were treated for 28 days. Clinical and mycological responses were determined during treatment and two weeks posttreatment. Ciclopirox olamine lotion 1% was found to be significantly more effective than its vehicle in the treatment of patients with common tinea pedis. Minor localized side effects (pruritus, burning sensation) were reported in 2% of 89 patients treated with ciclopirox olamine lotion 1%. The results demonstrate the bioequivalence of ciclopirox olamine lotion 1% and ciclopirox olamine cream 1% and confirm the clinical effectiveness and safety of the lotion in the treatment of tinea pedis, a generally recalcitrant fungal infection. It is concluded that ciclopirox olamine lotion 1% can be used as an alternative to ciclopirox olamine cream 1% for treatment of tinea pedis, tinea versicolor, tinea cruris, tinea corporis, and cutaneous candidiasis when the convenience and/or cosmetic elegance of a lotion is desired.

Administration, Topical↗