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Biomedical subjects

J Schachter

Publications and source records attributed to J Schachter.

At least 361 records · Page 20Linked to original sources
PubMedDate not supplied

Evaluation of Syva's enzyme immunoassay for the detection of Chlamydia trachomatis in urogenital specimens.

A newly developed microwell enzyme immunosorbent assay (EIA) system by Syva Company (Palo Alto, CA) can detect Chlamydia trachomatis in < 3 hr. It uses a polyclonal antibody to chlamydial lipopolysaccharide and end points are determined with a spectrophotometer. Three clinical trial sites (University of California Medical Center, San Francisco, CA; University of Washington, Seattle, WA; and Louisiana State University Medical Center, New Orleans, LA), compared this EIA with tissue culture (TC) for identifying Chlamydia in urogenital specimens. Overall prevalence by TC was 10.4% (136 of 1306). When tests were compared with TC (using vials or microtiter plates and a fluorescent antibody stain), we found an EIA sensitivity of 93.4% (127 of 136) and a specificity of 98.1% (1148 of 1170). This EIA has a performance profile that is, at the very least, comparable with other nonculture methods for diagnosing genital tract infections with C. trachomatis.

Antibodies, Bacterial↗
PubMedDate not supplied

Rifampin in chlamydial infections.

On a weight basis, rifampin is the antibiotic most active against Chlamydia trachomatis. Because of concerns about the ease with which resistance to rifampin emerges in vitro, few clinical trials of rifampin for the treatment of human chlamydial infections have been done. In those few studies, however, rifampin has been found to be as effective as tetracyclines for the treatment of C. trachomatis infection of the male urethra or for the topical treatment of trachoma.

Adult↗
PubMedDate not supplied

Overview of Chlamydia trachomatis infection and the requirements for a vaccine.

Chlamydia trachomatis is an important human pathogen. The development of vaccines designed to prevent C. trachomatis-associated morbidity would be highly desirable. In the developing world the major goal is the prevention of blindness due to trachoma; in industrialized societies and in some developing countries, the major goal is the prevention of chlamydial salpingitis and its consequences. In early trials of trachoma vaccine composed of a suspension of elementary bodies (the infectious particles), short-lived protective immunity was induced, but deleterious effects, i.e., hyperreactivity to infection, were also noted. Thus it is likely that separation of the protective from the sensitizing antigens and the development of a subunit vaccine will be necessary. Chlamydial virulence factors include the surface structures (presumably antigenic) that are responsible for specific attachment of the organism to a susceptible host cell, induction of phagocytosis by the host cell, or inhibition of phagolysosomal fusion. Serotype-specific neutralizing antigens might also be candidate antigens. Purification of such subunit antigens from chlamydial particles is probably impractical. It is likely that genetic engineering will be required for the production of cloned antigens after such antigens have been identified.

Bacterial Vaccines↗
PubMedDate not supplied

Role of cell-mediated immunity in chlamydial infection: implications for ocular immunity.

Cellular immunity to Chlamydia trachomatis is not well understood. Studies with the mouse pneumonitis agent in a mouse pneumonia model suggest a strong thymic component to immunity and a role for the macrophage as an effector cell in cell-mediated immunity to C. trachomatis. Experiments with Chlamydia psittaci indicate that cellular cytotoxic mechanisms and biostatic or cytotoxic mechanisms involving cytokines may also play a role in host defense against chlamydiae. Interferon has been shown to inhibit intracellular growth of both C. trachomatis and C. psittaci in vitro. Further studies are needed on the role of T lymphocytes or lymphokines and macrophages in limiting the growth of C. trachomatis in conjunctival epithelial cells (the most appropriate target cells) and in exerting a toxic effect on these cells. The evidence suggests that macrophages are activated during C. trachomatis infection; this activation may lead to the release of monokines (such as interleukin 1) that may be important in the pathogenesis of scarring due to over-stimulation of cellular immunity during ocular infection. Cell-mediated immunity to ocular infection with C. trachomatis may thus be a double-edged sword.

Animals↗
PubMedDate not supplied

Strategies for treatment and control of blinding trachoma: cost-effectiveness of topical or systemic antibiotics.

Treatment programs for prevention of blindness from trachoma in areas of endemicity are based on mass therapy, i.e., the topical application of antibiotic to the eyes of all persons in affected communities. When oral antibiotics are administered as a supplement to topical therapy, the healing rates among children with severe-intensity trachoma significantly improve. Moreover, the use of oral antibiotics (either tetracycline or doxycycline) in selected cases is a cost-effective strategy, particularly in communities where less than 20% of children have active trachoma. Systemic antibiotic treatment should be given only to children with severe- or moderate-intensity disease--those at significant risk of developing blindness. Children should be monitored carefully during systemic chemotherapy for adverse reactions.

Administration, Oral↗
PubMedDate not supplied

Pathogens associated with acute lower respiratory tract infection in young children.

To determine the agents associated with acute lower respiratory infection in young children, we studied 102 hospitalized children less than 5 years old using culture and serology for viruses and Chlamydia trachomatis, fluorescent antibody testing for pertussis and respiratory syncytial virus, blood cultures and counterimmunoelectrophoresis of nasopharyngeal secretions and urine for pneumococcal and Haemophilus influenzae type b antigens. At least one agent was detected in 87 children and multiple agents were found in 33. Viruses were detected 80 times; respiratory syncytial virus was most common (61 cases) and was detected as often by fluorescent antibody testing as by culture. C. trachomatis was detected in 10 children; all were less than 4 months old and 9 had mixed infections. Bacteria were detected 32 times, were usually pneumococcus (23) or H. influenzae (5) and were detected more often by counterimmunoelectrophoresis than by blood culture. Compared with children yielding only C. trachomatis or viruses, those with bacteria were significantly more likely to have fever, a band count over 2000/mm3 and radiographic consolidation. In this study acute lower respiratory infection was associated commonly with viruses, often with multiple pathogens but not with C. trachomatis after 4 months of age.

Child, Preschool↗
PubMedDate not supplied

Phasic heart rate responses: different patterns in black and in white newborns.

Click stimuli were presented during sleep to newborns from a low socioeconomic class urban population in Northeastern United States. Eighty-three black newborns showed less immediate poststimulus deceleration than did 67 white newborns. This difference was independent of heart rate level, and could not be accounted for by any of the perinatal variables studied, including birthweight and gestational age. These results suggest that in this population, black newborns differ from white newborns in the pattern of phasic heart rate responses to stimuli. This constitutes evidence for an additional difference in heart rate regulation in black as compared to white newborns from this population, since prior work reported differences in tonic heart rate level during sleep between black and white newborns.

Acoustic Stimulation↗