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Biomedical subjects

R Silberman

Publications and source records attributed to R Silberman.

9 recordsLinked to original sources

Tissue distribution of avidin and streptavidin injected to mice. Effect of avidin carbohydrate, streptavidin truncation and exogenous biotin.

Radioionated avidin and streptavidin were characterized for their biodistribution and tissue association in Balb/c mice, in comparison to their interaction with cells in vitro. Binding of avidin to spleen and bone-marrow cells in vitro was up to 20-fold higher than that of streptavidin, but when tested in vivo avidin clearance from blood and tissues was considerably faster than that of streptavidin. Levels of avidin at 24 h after an intravenous injection were below 1% (of the injected dose/mass tissue) in most organs. Non-glycosylated avidin was similar in its biodistribution to native avidin. Native streptavidin exhibited higher and prolonged tissue association with 5-10% levels in lung, liver, spleen, kidney and blood, whereas its truncated form showed low tissue levels (1-3%) but a remarkably high affinity to the kidney (80%). Exogenous biotin did not affect streptavidin distribution in vivo but caused a 2-7-fold increase in the retention of avidin (but not non-glycodylated avidin) in some of the organs.

Animals

Mycobacterium chelonae causing otitis media in an ear-nose-and-throat practice.

Seventeen cases of otitis media caused by Mycobacterium chelonae were detected among patients seen at a single ear-nose-and-throat (ENT) office (Office A) in Louisiana between May 5 and September 15, 1987. All the patients had a tympanotomy tube or tubes in place or had one or more tympanic-membrane perforations, with chronic otorrhea that was unresponsive to standard therapy with antimicrobial agents. Middle-ear exploration in six patients revealed abundant granulation tissue; multiple granulomas and acid-fast bacilli were demonstrated on a section of tissue from one patient with a nonhealing mastoidectomy incision. Thirteen of the 14 ear isolates obtained from patients seen in Office A had the same unusual pattern of high-level resistance to aminoglycosides. M. chelonae and other nontuberculous mycobacteria were recovered from several sources of water in Office A, as well as in another ENT office (Office B) in a neighboring city that was visited by the index patient. Only one additional case was detected in Office B during the same period. Otologic instruments in Office A were cleaned in an ultrasonic bath with tap water and a liquid detergent; the contents of the bath were changed only once weekly. Instruments in Office B were placed in boiling water between patient examinations. This outbreak establishes M. chelonae as an agent of otitis media and underscores the need for high-level disinfection or sterilization of ENT instruments between examinations to prevent the transmission of this organism to patients in the office setting.

Disease Outbreaks

Comparison of two selective media developed to isolate Pseudomonas cepacia from patients with cystic fibrosis.

Two media selective for Pseudomonas cepacia have been described recently: OF-polymyxinbacitracin-lactose agar (OFPBL) and P. cepacia agar (PCA). We compared these by culturing sputum from 27 patients with cystic fibrosis. Sputum from each patient was studied using streak-plate (SP) and quantitative (Q) culture methods. Five strains of P. cepacia were isolated from four patients (15%). P. cepacia was not found on routine media by SP or Q methods in three of the four patients. All five isolates grew on both OFPBL and PCA and all were recovered by SP and Q culture methods. Colony counts of P. cepacia obtained by Q cultures were similar on both selective media. Each of the selective media allowed the growth of other organisms; nineteen of 27 specimens cultured on OFPBL yielded non-P. cepacia spp. and six of 27 specimens cultured on PCA yielded non-P. cepacia spp. species (p less than 0.005). Pseudomonas aeruginosa was isolated from 26 of 27 patients on routine media (96%). This organism was recovered from four specimens cultured on OFPBL but from none on PCA (p less than 0.05). OFPBL and PCA are both selective for P. cepacia and enhance the ability to recover this organism from patients with cystic fibrosis using either SP or Q cultures of sputum; however, PCA is significantly more inhibitory for non-P. cepacia spp. than OFPBL.

Adolescent

Hepatitis B vaccine in healthy hospital employees.

A low rate of seroconversion to hepatitis B vaccine is reported. This occurred in healthy hospital employees from two separate institutions. A total of 236 individuals were evaluated in this study and only 53% or 124 persons developed protective levels of antibody to hepatitis B surface antigen following a complete vaccine series. In one hospital, 30% of the vaccine recipients developed antibody but not to a protective level. Employees who received the entire series in the arm or in the arm and buttock (mixed) had a significantly greater number of responders than employees who received the entire series in the buttock (P less than .05). Recipients aged 50 to 59 years had a significantly lower response rate to the vaccine (P less than .05). There was no correlation with the vaccinee's sex or the timing of the second injection. Vaccine was noted to have frozen in one hospital and accounted for some loss of antigenicity. This failure to respond to the vaccine has necessitated the use of booster injections of vaccine and continued antibody monitoring.

Adult

Comparison of 99mTc and 131I scans in thyroid function studies.

Thyroid function was studied in 170 patients, using technetium-99m (99Tc) and oral radio-iodine (131I); 110 patients had normal thyroid function, and 60 had hyperthyroidism. The 20-minute 99mTc uptake gave an accurate assessment of thyroid function in 95% of patients, and the 24-hour 131I uptake was accurate in 92%. One hundred 99mTc and 131I scintiscans were compared by 3 observers. Scans obtained with each isotope were of comparable quality, and in only 1 patient were both scans of poor quality. 99mTc is as good as 131I for assessing thyroid function and morphology, but has several advantages over 131I.

Evaluation Studies as Topic

Wound infection following cesarean section.

To investigate a high incidence of wound infections occurring in patients following cesarean section at a 650 bed charity hospital in Louisiana, a bacteriologic investigation was carried out. In this study, cultures were made at multiple sites prior to operation. An attempt was made to identify those bacteria that were predominately responsible for wound infection and their source, whether from the patient herself or from a nosocomial origin. The patients were divided into three groups depending on the degree of postoperative morbidity that followed. The bacterial flora in each group was relatively the same. Other factors were more significant in predicting those patients in whom postoperative morbidity occurred.

Cesarean Section