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Biomedical subjects

J Schachter

Publications and source records attributed to J Schachter.

At least 199 records · Page 11Linked to original sources
PubMed1987

The effect of cyclosporine in chlamydial eye infection.

The effect of cyclosporine (CsA) treatment in both primary and secondary Chlamydia trachomatis ocular infection in cynomolgus monkeys was studied. Following primary infection, CsA-treated animals developed severe clinical symptoms which persisted for up to 12 weeks compared to control animals which developed less severe inflammation lasting only 4 to 6 weeks. CsA treatment had no effect on the clinical course of a second ocular infection. Antigen-specific antibodies developed normally in the serum and tears of all animals, but the titer of IgM in serum and secreted IgA in tears of CsA-treated animals was significantly lower than control animals. Chlamydia-specific cell-mediated immunity, as determined by in vitro lymphoproliferation assays of peripheral blood, did not develop in either group of animals.

Animals↗
PubMed1987

Chlamydia trachomatis pneumonia in the immune, athymic and normal BALB mouse.

This paper compares the histopathology of pneumonia due to murine Chlamydia trachomatis (MoPn, mouse pneumonitis agent) in susceptible athymic nude mice (nu/nu), resistant heterozygous littermates (nu/+) and very resistant immunized nu/+ mice. While all groups had an early heterophil response, successful host defence correlated with the presence of large numbers of plasma cells, lymphocytes, monocytes, and lipid laden macrophages. Reticulate bodies were seen in all groups, predominantly in type I alveolar epithelial cells. By 24 h in the immune nu/+ group, no intact organisms were visible. Optimal control of infection was thus rapid and not clearly related to heterophils. These studies show that the histopathology of chlamydial infection may be quite atypical in the immunocompromised host, mononuclear cells seem critical in host defence, and B cell activation with plasma cell infiltration is dependent on intact T cell function in this model.

Animals↗
PubMed1987

Prophylactic effects of silver nitrate and erythromycin on Chlamydia psittaci conjunctivitis.

An animal model has been developed to study the effects of various prophylaxis agents on acquisition of chlamydial conjunctivitis. When Hartley strain newborn guinea pigs received ocular inoculations of Chlamydia psittaci followed by the instillation of various agents, 1% AgNO3 significantly lowered the risk of developing chlamydial conjunctivitis if it was administered within 15 min after the inoculation with C. psittaci. However, if the AgNO3 was administered at either 1 hr or 2 hr following inoculation, it did not have any prophylactic effect on the development of chlamydial conjunctivitis. Erythromycin ointment, 0.5%, was also found to prevent chlamydial conjunctivitis. The prophylactic effect was similar to placebo when the drug was given at 15 min; however, erythromycin ointment prophylaxis 1 hr or 2 hr after inoculation with C. psittaci was statistically superior to placebo.

Animals↗
PubMed1987

Oral immunization against chlamydial eye infection.

The effects of enteric administration of different preparations of Chlamydia trachomatis prior to ocular challenge with live chlamydia were compared to the immunity that develops after recovery from ocular infection. Oral immunization with either live homologous serovar B or with formalin-killed heterologus serovar L2 did not influence the response to subsequent ocular challenge. Although oral immunization with live serovar led to protection against heterologous ocular challenge with serovar B, oral immunization with noninfectious UV-irradiated serovar L2 led to more severe and prolonged disease. An immunizing regimen designed for maximal mucosal and systemic immunity also resulted in protection against homologous ocular challenge. Although protection was correlated with the presence of serum IgA antibodies, no clear mechanism for the protective ocular immunity to chlamydial infection has emerged. These studies show that it is possible to stimulate mucosal immunity to induce protection against subsequent ocular challenge with C. trachomatis that is equal to that which follows prior ocular infection.

Acute Disease↗
PubMed1986

Prospective study of perinatal transmission of Chlamydia trachomatis.

During a five-year period, 262 (4.7%) of 5,531 pregnant women had positive cervical cultures for Chlamydia trachomatis, and 131 of their infants were followed up prospectively to ascertain the outcome of chlamydial exposure during the birth process. Culture-confirmed inclusion conjunctivitis of the newborn was seen in 23 (18%) of the infants. Chlamydial pneumonia was diagnosed in 21 (16%) of the infants at risk. Chlamydia trachomatis was recovered from 47 of the infants (36%), while 79 (60%) showed serologic evidence of infection. Subclinical rectal and vaginal infections were detected in 14% of infants at risk. In our population, 2.8% of newborn infants show serologic evidence of perinatal chlamydial infection and 1.4% develop either chlamydial pneumonia or conjunctivitis. Incidence rates of this magnitude indicate the need for programs aimed at preventing perinatal transmission of C trachomatis.

Antibodies, Bacterial↗
PubMed1986

Experience with the routine use of erythromycin for chlamydial infections in pregnancy.

In an effort to prevent perinatal acquisition of Chlamydia trachomatis, we offered treatment with erythromycin ethylsuccinate (400 mg four times a day for seven days, given at 36 weeks' gestation) to 184 pregnant women with cervical chlamydial infections. Thirty-two women refused treatment; 24 of their infants were followed and served as the controls. Therapy was discontinued by 5 of 10 women who had gastrointestinal disturbances. Forty-seven women who completed therapy refused infant follow-up; in four (9 percent) of these women, therapy had failed to eradicate the infection. Sixty women and 59 infants completed the entire protocol; 55 (92 percent) of the women had negative cultures for chlamydia at follow-up. Chlamydial infection developed in 4 (7 percent) of the 59 infants of treated mothers, as compared with 12 (50 percent) of the 24 infants of untreated mothers; this difference was significant (P less than 0.001). With a success rate of 92 percent (98 of 107 patients) in treating maternal infection and with a relatively low intolerance rate (3 percent; 5 of 152), this regimen appears to be an effective, although not ideal, therapy for chlamydial infection in pregnant women. We conclude that in settings in which the prevalence of chlamydia infection is high, a routine program of screening pregnant women for cervical C. trachomatis, followed by treatment of those infected, would be cost effective and would reduce infant morbidity.

Chlamydia Infections↗
PubMed1986

Evaluation of fluorescein-conjugated monoclonal antibody test to detect Chlamydia trachomatis endocervical infections in adolescent girls.

We evaluated the fluorescein-conjugated monoclonal antibody (FA) test for screening for Chlamydia trachomatis endocervical infection in a general adolescent clinic. Three hundred sixty-three consecutive adolescent girls, ages 13 to 20 years (mean 17.3 years) were examined. Forty-five (12%) FA smears had insufficient cells. Reason for visit included non-lower genital tract-related disorders in 241 (76%) girls, and lower genital tract-related disorders in 77 (24%). C. trachomatis was isolated by tissue culture in 46 (14%) patients, and Neisseria gonorrhoeae by culture in 22 (7%), and Trichomonas vaginalis was identified by wet mount in 13 (5%). Compared with our tissue culture technique, the performance of the FA test was as follows: sensitivity 61% (28 of 46), specificity 97% (264 of 272), positive predictive value 78% (28 of 36), and negative predictive value 94% (264 of 282). There was no significant difference in test performance by race, although the sensitivity rate (64%) of the test in blacks was twice that (30%) in nonblacks. This apparent difference in test performance by race may actually represent variations in group characteristics, including exposure rate, susceptibility, and number of inclusion forming units available for tissue culture of Chlamydia in blacks compared with nonblacks. In our adolescent clinic, the tissue culture is superior to FA in detecting Chlamydia. We recommend that the FA test be used where tissue culture isolation for Chlamydia is not readily available, where known or predicted chlamydial infection rates are high, and where known or predicted numbers of inclusion forming units of Chlamydia in tissue culture are high.

Adolescent↗
PubMed1986

Experimental proctitis due to rectal infection with Chlamydia trachomatis in nonhuman primates.

To serially examine the immunopathogenesis and histopathology of rectal infection with Chlamydia trachomatis, we inoculated five cynomolgus monkeys with C. trachomatis serovar E (non-LGV) and five with serovar L2 (LGV). After inoculation, C. trachomatis was isolated from rectal cultures in three of five non-LGV-infected monkeys and in all five LGV-infected monkeys for a period of 10 weeks. LGV-infected monkeys developed a severe hemorrhagic ulcerative proctitis, in contrast to a mild proctitis in the non-LGV-infected monkeys. Hyperplasia of lymphoid follicles and a mucosal polymorphonuclear leukocyte and mononuclear cell infiltrate were evident in all infected monkeys. Crypt abscesses with giant cells and a rare granuloma formation were present in two of five LGV-infected monkeys. C. trachomatis inclusions were initially present in epithelial cells and later in tissue histiocytes. Experimental primate infection with C. trachomatis appears to clinically and histopathologically mimic rectal infection in humans and provides a model for immunopathogenesis studies in chlamydial proctitis and granulomatous proctitis.

Animals↗
PubMed1986

Comparison of monoclonal antibody staining and culture in diagnosing cervical chlamydial infection.

We compared a fluorescein-conjugated monoclonal antibody (FA) direct specimen test (MicroTrak; Syva Co., Palo Alto, Calif.) with culture (TC) in McCoy cells (vials, with blind passage and iodine staining of inclusions) for diagnosis of Chlamydia trachomatis infection in the cervix. Duplicate specimens were collected from 1,230 women, but for 262 of these subjects, both results were unavailable (150 FA smears were inadequate, indicating a need for clinical training in specimen collection), leaving 968 comparisons. Prevalence of chlamydiae by culture was 13% (126/968). Compared with TC results, the sensitivity of FA was 70% (88/126) and the specificity was 94% (795/842). There was a 91% agreement (883/968). The predictive value of a positive FA test was 65% (88/135), and that of a negative FA was 95% (795/833). We reexamined 38 smears for which paired results were discrepant, and the reread would have changed the result in only 5 of these. TC is less than 100% sensitive and some FA-positive, TC-negative specimens represent positive specimens not detected by TC. Unfortunately, it is not possible to identify which results in this group are truly false-positive. Clearly, the FA procedure has a performance profile which would make it a useful tool in screening high-risk populations (particularly when TC is not available) but it is less suited to screening low-risk populations, for which false-positive results are more important. The greater utility of the FA procedure in a venereal disease clinic was confirmed by testing 172 evaluable specimen pairs, of which 34 (20%) were Chlamydia isolate positive. The FA sensitivity was 76% (26/34) and specificity was 96% (133/138), giving a predictive value of 84% (26/31) for a positive test.

Antibodies, Monoclonal↗
PubMed1986

Use of gonozyme on urine sediment for diagnosis of gonorrhea in males.

We compared enzyme immunoassay (Gonozyme; Abbott Laboratories, North Chicago, Ill.) for detection of gonococcal antigen in urine sediments with urethral swab culture for diagnosis of gonorrhea in men attending a venereal disease clinic. The prevalence of infection was 14% by culture (27/196). The sensitivity of enzyme immunoassay was 93% (25/27) compared with the culture method, and the specificity was 99% (167/169). The ability to detect gonococcal antigen in urine sediment may provide the basis for a noninvasive method of screening for gonococcal infection.

Antigens, Bacterial↗
PubMed1986

Accuracy of immunoglobulin M immunoassay for diagnosis of chlamydial infections in infants and adults.

An improved solid-phase enzyme immunoassay (EIA) with Chlamydia trachomatis L2 434/Bu elementary bodies was developed for the measurement of immunoglobulin M (IgM) antibody to C. trachomatis in serum. Comparison of EIA and microimmunofluorescence IgM antibody titers of 156 serum samples revealed an EIA sensitivity and specificity of 100% for infants, but reduced sensitivity (85%) and specificity (76%) for sera from adults. Sera containing IgM class rheumatoid factor produced false-positive IgM results which could easily be eliminated by pretreatment of the sera with anti-human IgG. Analysis of sera from infants with chlamydial infections revealed that 17 of 17 infants with C. trachomatis pneumonia had high IgM antibody titers (geometric mean titer, 1:64,812), whereas two infants with conjunctivitis only lacked detectable IgM antibody. EIA detected IgM antibody to several serovar groups in serum, including serovars B, BDE, FG, and J. IgM antibody to C. trachomatis in serum was detected as early as 5 days after the infection that was acquired at delivery and persisted for 3 months. The availability of an EIA possessing good sensitivity and specificity for the detection of IgM antibody to C. trachomatis may permit more laboratories to diagnose perinatal chlamydial infections.

Adult↗
PubMed1985

[Chlamydia infections].

Chlamydia trachomatis represents one of the most common causative agents of sexually transmitted diseases. Clinically, genital chlamydial infections are similar to gonorrhoea. Although the clinical symptoms in chlamydial infections are usually milder than those in gonorrhoea, late complications are more common and more dangerous, because the carriers may easily escape notice. The knowledge of chlamydial infections has increased during the last few years. The present report deals with recent developments in this field.

Bacteriological Techniques↗
PubMed1985

Oral contraceptives, Chlamydia trachomatis infection, and pelvic inflammatory disease. A word of caution about protection.

Management of pelvic inflammatory disease (PID) and decisions about contraception are being influenced by reports that oral contraceptives decrease the risk of PID. To evaluate the validity of this association, we have examined published epidemiologic evidence and reviewed relevant information from other disciplines. Current information does not permit the generalization that oral contraceptives protect against all forms of PID. Most studies conducted (1) have been limited to hospitalized women, who represent less than 25% of all PID cases and are likely to have relatively severe forms of the disease, and (2) have failed to distinguish between gonococcal and nongonococcal PID. While oral contraceptives may provide some protection against gonococcal PID, no basis exists for assuming similar protection is provided against chlamydial PID. In fact, epidemiologic and biologic evidence suggests that infection with Chlamydia trachomatis, the leading cause of nongonococcal PID, is enhanced by oral contraceptives. We judge the conclusion that oral contraceptives protect against all PID to be premature, and urge caution in its application in health policy and clinical decisions.

Animals↗