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Biomedical subjects

M A Gerber

Publications and source records attributed to M A Gerber.

At least 181 records · Page 10Linked to original sources
PubMed1985

Twice-daily penicillin in the treatment of streptococcal pharyngitis.

An investigation was performed to compare the effectiveness of oral penicillin V given twice daily with penicillin V given three times daily in the treatment of group A beta-hemolytic streptococcal (GABHS) pharyngitis. Patients were randomly assigned to receive 250 mg of penicillin V either two or three times daily for ten days. Overall, 23 (23%) of 99 patients had the same strain of GABHS isolated from their follow-up as from their initial throat culture and were considered to have bacteriologic-treatment failures. Of the 50 patients in the three-times-daily group, nine (18%) had bacteriologic-treatment failures, while 14 (28.5%) of 49 patients in the twice-daily group had bacteriologic-treatment failures. The results of this and earlier investigations suggest that penicillin V given twice daily is as effective as penicillin V given three times daily for the treatment of GABHS pharyngitis.

Administration, Oral↗
PubMed1985

Secretion of polyalbumin receptors in vitro.

The nature of hepatitis B surface antigen (HBsAg)-associated receptors for polymerized human serum albumin (pHSA-R) and their relationship to hepatitis B e antigen (HBeAg) and human serum proteins have not been defined. We studied by radioimmunoassay and by electron microscopy HBsAg-associated pHSA-R secreted in vitro by a human hepatocellular carcinoma cell line (PLC/PRF/5) and by mouse 3T3 fibroblasts after transfection with cloned hepatitis B virus (HBV) DNA (4.10 cells). PLC/PRF/5 cells expressed only HBsAg, whereas 4.10 cells secreted also HBeAg. There was no significant difference in the production of HBsAg, HBeAg, and pHSA-R when the cells were cultured in the presence or absence of fetal calf serum. Secretion of pHSA-R by the two cell lines for a given amount of HBsAg was equal irrespective of the presence or absence of HBeAg. Supernatants from both cell lines grown in serum-free medium did not contain any Clq or albumin when tested by immunodiffusion. The ability of a transfected mouse cell line to produce HBsAg with pHSA-R activity strongly suggests that pHSA-R is coded by the HBV genome and does not depend on the presence of human serum proteins. In addition, our findings fail to demonstrate any correlation between HBeAg production and pHSA-R.

Animals↗
PubMed1985

Critical appraisal of the clinical relevance of rapid diagnosis in pediatrics.

To assess the potential impact of rapid diagnostic tests on the care of the pediatric patient a critical evaluation of the antigen detection tests currently available for two important pediatric diseases--Haemophilus influenzae type b meningitis and group A beta-hemolytic streptococcal pharyngitis--is presented. Antigen detection tests for Haemophilus influenzae type b meningitis are of value primarily as an adjunct to traditional procedures, whereas antigen detection tests for the rapid diagnosis of group A beta-hemolytic streptococcal pharyngitis could, in the near future, replace the blood agar culture. This comparison demonstrates that the evaluation of a new diagnostic test should include not only a determination of its accuracy, but, in addition, a determination of its advantages over current methods, the frequency with which the test will be performed, the consequences of a false-negative or false-positive test result, and the potential impact on patient care resulting from use of the test.

Antigens, Bacterial↗
PubMed1985

Effect of antibiotic therapy on the clinical course of streptococcal pharyngitis.

We examined the effect of antibiotic therapy on the clinical course of group A beta-hemolytic streptococcal (GABHS) pharyngitis in 260 children. After a throat culture had been obtained, each child was evaluated for the presence of predetermined signs and symptoms, and was then randomized in a double-blind manner to receive penicillin V, cefadroxil, or placebo. Of the 194 children with throat cultures positive for GABHS, 68 received penicillin V, 70 received cefadroxil, and 56 received placebo. Approximately 18 to 24 hours later, each patient returned for reevaluation. Significantly fewer children who had received either penicillin or cefadroxil had persistence of each of the three objective signs and each of the three subjective symptoms than did children who had received placebo. In addition, the evaluating physician, parents, and patients all believed that significantly fewer of the patients given antibiotic failed to demonstrate overall clinical improvement.

Adolescent↗
PubMed1985

Colonic ulceration in histiocytosis X.

Gastrointestinal symptoms in histiocytosis X are distinctly unusual. This report describes a 5-month-old infant with a prolonged history of lower gastrointestinal bleeding which was found to be caused by diffuse histiocytic infiltration of the colon. Immunopathologic and electron microscopic studies confirmed the diagnosis of histiocytosis X. The differential diagnosis of lower gastrointestinal bleeding in young children should include histiocytosis X.

Colon↗
PubMed1985

Effects of glycosylation inhibitors on the expression of polyalbumin receptors by hepatitis B surface antigen produced in vitro.

In this study we examined the role of secondary modifications in the expression of polyalbumin receptors by hepatitis B surface antigen (HBsAg) produced in vitro. Several clones isolated from 3T3 mouse fibroblasts after transfection with the hepatitis B virus genome produced HBsAg with marked variation in the expression of polyalbumin receptors. Treatment of the cells with glycosylation inhibitors (tunicamycin, glucosamine) resulted in loss of the 27 000 mol. wt. HBsAg glycopolypeptide, concomitantly with a marked increase in polyalbumin receptors. These data suggest that glycosylation regulates the activity of polyalbumin receptors associated with native HBsAg.

Animals↗
PubMed1985

Applicability of imprints to immuno-ultrastructural studies of lymphoid tissues.

In order to evaluate the applicability of imprints to immuno-ultrastructural studies of lymphoid tissues, we compared distribution pattern and morphology of B cells, T cells, T-cell subsets, and follicular dendritic reticulum cells (DRC) at the light and ultrastructural level in imprints and sections of tonsils and lymph nodes. The surface antigenic profile of lymphoid cells was revealed with monoclonal antibodies in an avidin-biotin-peroxidase complex (ABC) method. Distribution of lymphoid cells in coherent areas of imprints recapitulated their disposition in sections of respective lymphoid tissues. Preservation of microanatomical relationships and ultrastructure of lymphoid cells in imprints allowed evaluation of associations and fine structural detail of lymphoid cells. Morphologic configurations of B cells in imprints, confined to round aggregates, were similar to fine structural morphology of B cells in mantle zones (MZ) and germinal centers (GC). Processes of DRCs in imprints formed conformations resembling their meshwork within follicles and mantled lymphoid cells. In imprints and sections, lymphocytes of cytotoxic/suppressor phenotype had a large amount of cytoplasm with many organelles. In contrast, cells of helper/inducer phenotype displayed a high nucleocytoplasmic (N/C) ratio and small numbers of organelles. Thus, imprints represent an easy, fast, and reliable method that lends itself to immunoultrastructural studies of lymphoid tissues.

Antibodies, Monoclonal↗
PubMed1985

Effect of atmosphere of incubation on the isolation of group A streptococci from throat cultures.

The optimal atmosphere of incubation for the isolation of group A beta-hemolytic streptococci from throat cultures has been the subject of considerable debate. To resolve this issue, we examined 5992 consecutive throat cultures performed at a private pediatric office in children with acute upper respiratory tract infections. All throat cultures were streaked onto duplicate blood agar plates, one of which was then incubated anaerobically and the other aerobically. beta-Hemolytic streptococci were isolated in cultures from 1885 (31.5%) of the patients; 1479 (24.7%) were identified as group A, and 406 (6.8%) were identified as non-group A. Group A streptococci were recovered significantly more often from the plates incubated anaerobically than from those incubated aerobically (1467 vs. 1054; anaerobic only, 425; aerobic only, 12; P less than 0.01). Non-group A streptococci were also recovered significantly more often from the plates incubated anaerobically than from the plates incubated aerobically (397 vs. 170; anaerobic only, 236; aerobic only, 9;P less than 0.01). Anaerobic incubation maximizes the yield of the throat culture. The additional cost and effort of anaerobic incubation are small, and would appear to be justified by the increased isolation rate of group A beta-hemolytic streptococci. The significance of the increased isolation rate of non-group A beta-hemolytic streptococci with anaerobic incubation needs to be investigated further.

Adolescent↗
PubMed1985

Massive hepatic necrosis after chemotherapy withdrawal in a hepatitis B virus carrier.

A chronic hepatitis B virus (HBV) carrier with diffuse nodular transformation of the liver and malignant lymphoma in the lymph nodes and spleen developed massive hepatic necrosis and died three weeks after the third cycle of chemotherapy. Immunosuppressive drug treatment may favor replication of HBV, resulting in massive hepatocyte destruction when the immune response recovers following withdrawal of chemotherapy. This outcome must be considered in patients with chronic hepatitis B who are treated with a course of prednisone followed by antiviral therapy as well as in HBV carriers following chemotherapy for malignant disease.

Antineoplastic Agents↗
PubMed1984

Radioimmunometric assay for hepatitis B surface antigen on the surface of infected cells.

It has been difficult to differentiate hepatitis B surface antigen (HBsAg) on the cell surface from intracellular or intramembranous HBsAg that is not exposed to the host immune response. We describe here a radioimmunometric assay for HBsAg on the cell surface using HBsAg producing hepatocellular carcinoma cell lines and fibroblasts transfected with cloned hepatitis B virus DNA as models. The assay is sensitive, specific, simple and takes approximately 1 1/2 h. The procedure may be modified to compare quantitatively cell surface with intracellular HBsAg and to demonstrate other cell associated hepatitis B virus antigens such as HBcAg and HBeAg.

Animals↗
PubMed1984

Latex agglutination tests for rapid identification of group A streptococci directly from throat swabs.

A comparison of the accuracy and practicality of two new latex agglutination tests for the rapid identification of group A beta-hemolytic streptococci directly from throat swabs was performed in a busy pediatric office. The Directigen Group A Strep Test kit had a sensitivity of 84%, specificity 99%, positive predictive value 99%, and negative predictive value 93% when compared with blood agar cultures. The Culturette Brand 10-Minute Group A Strep ID Kit had a sensitivity of 83%, a specificity 99%, positive predictive value 97%, and negative predictive value 93% when compared with blood agar cultures. When cultures with less than 10 colonies of group A beta-hemolytic streptococci per plate were not considered positive, both rapid tests had a sensitivity of 95%. The Culturette Brand test required considerably less time, equipment, supplies, and skill than the Directigen test. Only the Culturette Brand test appeared to be practical for routine use in a pediatrician's office. Further investigations of the accuracy of both of these rapid tests need to be performed before either is accepted as a substitute for the throat culture.

Adolescent↗
PubMed1984

Role of Chlamydia trachomatis in acute pharyngitis in young adults.

It has recently been suggested that Chlamydia trachomatis may be a common cause of acute pharyngitis in adults. In a prospective investigation of 95 college students with acute pharyngitis, C. trachomatis was not isolated from any pharyngeal cultures. Further investigations are needed to better define the role of C. trachomatis in upper respiratory tract infections.

Acute Disease↗
PubMed1984

Influence of methimazole on murine thyroiditis. Evidence for immunosuppression in vivo.

Thionamide drugs are immunosuppressives in vitro. To examine this action in vivo, A/J mice were immunized with human thyroglobulin (hTg) (0.5 mg intraperitoneal injections for 5 d) beginning on days 6, 24, and 43 with or without methimazole (M) (0.05%) and l-thyroxine (T4) (0.1 micrograms/ml to prevent thyroid hypertrophy) in their water supply. Groups (n = 8) were killed on days 37, 42, and 59. Spontaneous splenic IgG-secreting cells determined by Staphylococcus protein A-linked sheep erythrocytes (SRBC) via indirect plaque-forming cell (PFC) assay indicated polyclonal stimulation induced by the hTg exposure (controls = 2,285 +/- 599, hTg-only = 5,570 +/- 470 PFC per 10(6) spleen cells), but this was significantly reduced in the M plus T4-treated group (3,640 +/- 415 PFC, P = 0.05). hTg antibody was measured by specific PFC assay using hTg-linked SRBC. Anti-hTg PFC were absent in controls and were 147 +/- 41, 25 +/- 8, and 173 +/- 58 PFC per 10(6) spleen cells in the hTg-only groups on days 37, 42, and 59, respectively. Anti-hTg PFC results in the M plus T4-treated animals were significantly reduced to 0, 15 +/- 5, and 63 +/- 30 anti-hTg PFC. Histological examination revealed a marked thyroiditis in hTg-only animals and a significantly reduced degree of mononuclear cell infiltration and follicular destruction in the M plus T4-treated groups (graded 1.9 compared with 3.6 in hTg-only P = less than 0.01). Examination of IgG deposition using fluorescent anti-mouse IgG revealed a similar granular pattern and degree of staining in both immunized groups. Control animals that received concurrent T4 administration alone showed similar hTg-induced murine thyroiditis to non-T4-treated animals and could not explain the apparent immunosuppression observed. In conclusion, these data demonstrated that M reduced both the splenic immune response and the degree of thyroiditis after heterologous Tg immunization, while a quantitative difference in the circulating and intrathyroidally deposited Tg antibody was not detected.

Animals↗
PubMed1984

Delta virus infection and severe hepatitis. An epidemic in the Yucpa Indians of Venezuela.

Over a 3-year period, 149 Yucpa Indians in Venezuela developed hepatitis; 34 persons died and at least 22 developed chronic hepatitis. Children and young adults were primarily affected, especially males. Serologic testing showed that hepatitis B virus infection was highly endemic in this population, but also that 65% of patients had hepatitis B virus surface antigen (HBsAg) during or after illness. Most patients had evidence of delta-agent superinfection; 86% of HBsAg-positive patients had delta antibody, and delta antigen was found in specimens taken during autopsies on 7 of 9 patients. Serologic data suggested that most infections were due to delta superinfection of hepatitis B carriers, and that more than 60% of these infections progressed to chronic disease. Delta agent infection, and particularly delta superinfection of hepatitis B carriers, appears to be an ominous occurrence that may develop in populations among whom hepatitis B virus infection is endemic, and who have no other risk factor for delta infection.

Adolescent↗