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Biomedical subjects

J Schachter

Publications and source records attributed to J Schachter.

At least 109 records · Page 6Linked to original sources
PubMed1993

In vitro activity of azithromycin (CP-62,993) against Chlamydia trachomatis and Chlamydia pneumoniae.

The in vitro susceptibilities of 49 strains of Chlamydia trachomatis and 3 strains of Chlamydia pneumoniae to azithromycin and tetracycline or doxycycline were determined. The MIC of azithromycin ranged from < or = 0.06 to 1.0 micrograms/ml, the MIC of tetracycline ranged from 0.03 to 0.12 micrograms/ml, and the MIC of doxycycline ranged from 0.015 to 0.06 micrograms/ml against C. trachomatis. The MIC ranges for C. pneumoniae were 0.12 to 0.25 micrograms/ml for azithromycin and 0.06 to 0.12 micrograms/ml for tetracycline. All minimal chlamydicidal concentrations were either equal to the MIC or one or two dilutions higher. No strains resistant to these antibiotics were detected. In vitro activity shows that azithromycin is highly active against C. trachomatis and C. pneumoniae.

Azithromycin↗
PubMed1993

Lack of allelic polymorphism for the major outer membrane protein gene of the agent of guinea pig inclusion conjunctivitis (Chlamydia psittaci).

The major outer membrane protein gene (omp1) was sequenced for each of six Chlamydia psittaci (guinea pig inclusion conjunctivitis [GPIC]) strains isolated from guinea pigs. Five of the isolates were obtained in the United States during the 1960s and 1970s, including the prototype strain isolated by Murray in 1962. The other isolate was obtained from a guinea pig in England. The nucleotide sequence of the omp1 gene for each strain was identical. The lack of omp1 allelic polymorphism among GPIC isolates suggests that, unlike C. trachomatis, the GPIC agent lacks antigenic variation in the major outer membrane protein.

Alleles↗
PubMed1993

Gamma interferon levels during Chlamydia trachomatis pneumonia in mice.

Host defense against murine Chlamydia trachomatis (mouse pneumonitis agent [MoPn]) in a murine model was investigated. Gamma interferon (IFN-gamma) was produced in the lungs by both MoPn-susceptible nude athymic (nu/nu) and MoPn-resistant heterozygous (nu/+) mice. In vivo depletion of IFN-gamma in nu/nu mice led to exacerbation of infection. Fluorescence-activated cell sorter analysis disclosed induction of GL3 antibody-positive cells (putatively gamma/delta+ T cells) in nu/nu mouse lung during infection with MoPn. Treatment of nu/nu mice in vivo with antibody to NK cells (anti-asialo GM1 antibody) or to gamma/delta cells (UC7-13D5) did not significantly decrease IFN-gamma production in the lung. However, treatment of severe combined immunodeficiency mice (which lack gamma/delta cells) with antibody to NK cells significantly reduced lung IFN-gamma levels.

Animals↗
PubMed1993

Evaluation of chlamydiazyme enzyme immunoassay for detection of Chlamydia trachomatis in urine specimens from men.

Paired first-voided urine and urethral swab specimens were collected from 540 men attending sexually transmitted disease clinics in three geographic locations. Urine specimens were tested for the presence of Chlamydia trachomatis by commercial enzyme immunoassay (Chlamydiazyme), and the results were compared with those of urethral swab cultures. Overall prevalence of urethral C. trachomatis by culture was 14%, and the Chlamydiazyme assay had an overall sensitivity of 83%, a specificity of 96%, a positive predictive value of 76%, and a negative predictive value of 97%. Sensitivity was greater (94%) in those culture-positive samples with a high antigen load (> or = 20 inclusion-forming units per coverslip) than those with a lower antigen load (68%). Assay of urine specimens from men attending sexually transmitted disease clinics by Chlamydiazyme appears to be a reliable, noninvasive method of detection of C. trachomatis infection, and further evaluation of its performance in asymptomatic and low-prevalence populations is indicated.

Antigens, Bacterial↗
PubMed1993

A seroepidemiologic study of Chlamydia pneumoniae in Rhode Island. Evidence of serologic cross-reactivity.

OBJECTIVE: Although Chlamydia pneumoniae is considered a common cause of pneumonia worldwide, the evidence is mainly serologic. Therefore, we examined whether the currently used chlamydial microimmunofluorescence (MIF) antibody test is specific for C pneumoniae infection. DESIGN AND SETTING: Secondary analysis of data from a cohort study of sarcoidosis among the graduates of ten consecutive apprenticeship classes of firefighters and police officers. PARTICIPANTS: One hundred forty-seven young adult men. MEASUREMENTS: Immunoglobulin G and M antibodies to C pneumoniae, 15 serovars of C trachomatis, and 2 strains of C psittaci as measured by MIF. RESULTS: Evidence of previous C pneumoniae and C trachomatis infection (IgG > or = 1:16 yet < 1:512) was present in 108 (73 percent) and 59 (40 percent) subjects, respectively. Serologic evidence of recent C pneumoniae and C trachomatis infection (IgM > or = 1:16 or IgG > or = 1:512) was present in 19 (13 percent) and 14 (10 percent) subjects, respectively. Chlamydia pneumoniae and C trachomatis IgM titers were highly correlated (r = 0.80; 95 percent CI, 0.73 to 0.85) while C pneumoniae and C trachomatis IgG titers were fairly correlated (r = 0.44; 95 percent CI, 0.30 to 0.56). CONCLUSIONS: The C pneumoniae seroprevalence of 86 percent is the highest yet reported. The correlations between C pneumoniae and C trachomatis antibody titers suggest that chlamydial MIF may be less specific than is generally appreciated. Moreover, the observed 13 percent seroprevalence of recent C pneumoniae infection in a healthy working population challenges the serologically based belief that this agent accounts for 6 to 10 percent of community-acquired pneumonia. A more objective, more specific test is needed in the serodiagnosis of C pneumoniae infection.

Adult↗
PubMed1993

The relationship of Chlamydia trachomatis infection and male infertility.

OBJECTIVES: Infertility affects at least 2 million couples in the United States. One third of infertility is attributed to male causes, but the etiology of most male infertility remains obscure. This study was designed to investigate the relationship between Chlamydia trachomatis and unexplained infertility in men. METHODS: Questionnaires and serum were collected prospectively from 52 case subjects (men from couples with explicitly defined idiopathic infertility) and 79 control subjects (first-time expectant fathers). RESULTS: Case subjects were significantly more likely than control subjects to be seropositive for antibody to C trachomatis at a titer of 1:64 or higher. By test of trend, higher titers were associated with higher odds ratios. Adjustment for age of either partner at initiation of pregnancy attempt, race, income, previous genitourinary symptoms or diagnoses, number of previous sexual partners, and barrier contraceptive use had no significant effect on the estimate of the odds ratio. One half of the men who were antibody positive had no history of genitourinary symptoms. CONCLUSIONS: Our results suggest an association between infection with C trachomatis in men and unexplained infertility and imply that infection is frequently asymptomatic.

Adult↗
PubMed1993

Deeper diagnosis. Multiple determinants of an illness experience.

This paper identifies the multiple determinants of a complex illness experience and describes the difficult process of diagnosis and management. The crucial coordination and integration role of the family physician is explained. The perspectives of the family physician, the consulting psychologist, and the patient are elucidated. Interventions by physicians from various specialties are identified and explored. Psychological determinants, including those rooted in the patient's history, are revealed in parallel with the physiological manifestations.

Adult↗
PubMed1992

Long-term sequelae of acute pelvic inflammatory disease. A retrospective cohort study.

OBJECTIVE: Our objective was to prospectively assess the frequency and predictors of long-term sequelae of acute pelvic inflammatory disease. STUDY DESIGN: We performed a retrospective cohort study of 140 women admitted for treatment of pelvic inflammatory disease to San Francisco General Hospital in 1985, locating and interviewing 51 women by telephone a median of 37 months later. RESULTS: Twelve (24%) women had pelvic pain for 6 months or more after hospitalization, 22 (43%) had subsequent episode(s) of pelvic inflammatory disease, and 40% were involuntarily infertile. A history of pelvic inflammatory disease prior to admission was associated with infertility (p = 0.05), chronic pelvic pain (p = 0.03), and pelvic inflammatory disease subsequent to hospitalization (p = 0.06). Longer duration of abdominopelvic pain before admission and younger age at the time of first sexual intercourse were associated with both infertility (p = 0.02, p = 0.04) and subsequent pelvic inflammatory disease (p = 0.04, p = 0.0008). CONCLUSIONS: Further studies are needed to more accurately assess the incidence and predictors of long-term sequelae of pelvic inflammatory disease. A reduction in adverse outcome will require more stringent efforts at education and reduction of risk-taking behaviors.

Acute Disease↗
PubMed1992

The characterization of nonbacterial prostatitis: search for an etiology.

Nonbacterial prostatitis is often difficult to differentiate from other prostatic complaints and remains a vaguely characterized syndrome. Prostatic fluid inflammatory cells and elevated immunoglobulins raise the suspicion that this syndrome is caused by some undetected infection. Prostatic fluid antibodies against Chlamydia trachomatis, Ureaplasma urealyticum, staphylococcus, Staphylococcus faecalis, Bacteroides fragilis and Clostridium perfringens were measured in men with nonbacterial and bacterial prostatitis, and men without urinary symptoms by an enzyme-linked immunosorbent assay. Prostate specific antigen and prostatic acid phosphatase were measured in the prostatic fluid as indirect measures of secretory activity. Of 44 men with nonbacterial prostatitis 9 (20%) had detectable prostatic fluid antichlamydial antibody titers, compared with 3 of 25 control men (12%) and 2 of 13 (15%) with bacterial prostatitis--no evidence for a higher prevalence of prostatic fluid antichlamydial antibody in men with nonbacterial prostatitis. Prostatic antibodies to the other organisms were rarely detected. When compared with unaffected men the low levels of prostate specific antigen and prostatic acid phosphatase, and more alkaline prostatic fluid in men with bacterial and nonbacterial prostatitis suggest that secretory dysfunction accompanies the inflammation. These data show that none of the organisms studied caused the majority of the cases of nonbacterial prostatitis and that either an agent as yet unidentified or multiple agents may be involved in the etiology of nonbacterial prostatitis.

Acid Phosphatase↗
PubMed1992

Persistent infection with Chlamydia pneumoniae following acute respiratory illness.

Chlamydia pneumoniae is emerging as a significant cause of respiratory disease, including pneumonia and bronchitis, in humans. In this recently completed study of infection due to C. pneumoniae in patients presenting with pneumonia to SUNY Health Science Center at Brooklyn, we identified two individuals for whom cultures were positive on multiple occasions over a 1-year period. To determine the frequency of persistent respiratory infection with C. pneumoniae, follow-up specimens were obtained from nine individuals with culture-documented C. pneumoniae infection. Five of these individuals had persistent infection: four had a flulike illness characterized by pharyngitis, and one had bronchitis with prominent bronchospasm. All five individuals appeared to have acute C. pneumoniae infection as determined by results of serologic tests (titers of IgM antibody for all individuals were greater than or equal to 1:16). For three patients, cultures remained positive for 11 months despite therapy with 10- to 21-day courses of tetracycline or doxycycline. These observations suggest that persistent infection with C. pneumoniae may follow acute infection and may persist for many months. Infection with C. pneumoniae may be very difficult to eradicate with use of currently available antibiotics even if there is a clinical response to therapy.

Acute Disease↗
PubMed1992

Comparison of the major outer membrane protein variant sequence regions of B/Ba isolates: a molecular epidemiologic approach to Chlamydia trachomatis infections.

The molecular evaluation of the chlamydial major outer membrane protein (MOMP) gene (omp1) can facilitate epidemiologic investigations of this pathogen. Genotyping of omp1 provides a more precise characterization of Chlamydia trachomatis than do current immunotyping techniques. Genetic omp1 variants of serovars that are responsible for ocular disease in Tunisia were identified. Archival conjunctival samples collected during 1972 and 1975 from trachoma patients in Douz were sequenced by automation along with additional B and Ba trachoma and genital isolates. Over 90% of the nucleotide changes resulted in an amino acid substitution. Different amino acid sequence changes in variable segments 1, 2, and 4 were found in the specimens collected in 1975 from those collected in 1972. Determination of omp1 genotypes responsible for trachoma will be useful for prospective, epidemiologic studies to identify chlamydial reservoirs within the host, evaluate transmission patterns, and determine the antigenic variation of MOMP for rational vaccine development.

Amino Acid Sequence↗
PubMed1992

Evaluation of the humoral immune response in trachoma to Chlamydia trachomatis major outer membrane proteins by sequence-defined immunoassay.

The Chlamydia trachomatis immunodominant major outer membrane protein (MOMP) is both a target of neutralizing antibodies and the serotyping antigen and thus has been a focus of diagnostic, seroepidemiologic, and experimental investigations. The microimmunofluorescence (MIF) test has been the principal tool in serologic investigations of chlamydial infections but is difficult and expensive for routine use; moreover, since it uses whole organisms as antigen, it is incapable of revealing the molecular specificity of the humoral response to infection. These limitations were resolved by using synthetic peptides corresponding to serovar-specific antigenic regions of MOMP in an ELISA-based format to analyze the serospecificity of sera from trachoma cases. The ELISA reaction to the surface-exposed MOMP sequence variable segment 1 was immunodominant and serovar-specific and was in concordance with serovar specificity according to paired MIF test determinations. Understanding the patterns of humoral responses to MOMP determinants in patient populations will advance our knowledge of their role in the immunobiology of naturally acquired infection.

Amino Acid Sequence↗
PubMed1992

Chlamydia trachomatis pneumonia induces in vivo production of interleukin-1 and -6.

Cytokine induction during Chlamydia trachomatis pneumonia may alter the pathogenesis or course of disease. We examined interleukin-1 (IL-1) and IL-6 production by measuring mRNA and bioactivity in murine lungs. mRNA and bioactivity for IL-1 alpha, IL-1 beta, and IL-6 increased after Chlamydia infection. These cytokines may be important in regulating host defenses against C. trachomatis.

Animals↗
PubMed1992

Multicenter evaluation of the AntigEnz Chlamydia enzyme immunoassay for diagnosis of Chlamydia trachomatis genital infection.

To evaluate the AntigEnz Chlamydia enzyme immunoassay (EIA) (Baxter/Bartels, Issaquah, Wash.), we studied 320 men and 1,209 women attending clinics for sexually transmitted diseases in Baltimore, San Francisco, and Seattle. At examination, two separate swabs were obtained from each patient, one for chlamydial culture and one for EIA. Cervical samples were collected from women, and urethral samples were collected from men. The prevalence of chlamydial infection by culture was 9% in Baltimore (n = 532), 11% in Seattle (n = 500), and 9% in San Francisco (n = 497). To resolve specimens with discrepant culture and EIA results, the EIA transport buffer was centrifuged and the resuspended pellet was stained by direct immunofluorescence to determine whether elementary bodies were present. Overall sensitivity of the AntigEnz Chlamydia assay compared with culture was 87% in men and 86% in women, and overall specificities were 94 and 97%, respectively. Differences between centers were seen, with sensitivities ranging from 76% among men and 79% among women in Seattle to 100% among men and 95% among women in Baltimore. With a true positive considered to be either a culture-positive or an EIA- and direct immunofluorescence-positive specimen, the revised sensitivity was 91% in men and 88% in women. Overall revised specificity was 99% in both men and women. We conclude that in this high-prevalence population, the sensitivity and specificity of this assay compare favorably with those of other noncultural antigen detection tests for the diagnosis of chlamydial genital infection.

Antigens, Bacterial↗