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Biomedical subjects

J Schachter

Publications and source records attributed to J Schachter.

At least 217 records · Page 12Linked to original sources
PubMed1985

Chlamydial endocervical infections and cytologic findings in sexually active female adolescents.

The association of infection with Chlamydia trachomatis and cytologic changes on Papanicolaou smear was examined in 148 sexually active postmenarchial++ female subjects, aged 13 to 21 years (mean = 17.2) attending a teen clinic. Endocervical samples for micro-organisms (C. trachomatis and Neisseria gonorrhoeae) and a cervical sample for cytologic examination were taken. A detailed evaluation of the cytologic results was made independently of the C. trachomatis status. In 23 (15.5%) subjects tests for isolation of C. trachomatis were positive. Inflammatory changes in epithelial cells, nuclear changes in metaplastic cells, and lymphocytes in the inflammatory exudate were associated with C. trachomatis isolation but suspected "chlamydial inclusions" and cytoplasmic vacuoles in metaplastic cells were not. The results reported here do not support the use of cervical cytologic examination as a definitive diagnostic test for presence of an endocervical chlamydial infection. However, it may be possible to use the cytologic pattern described here to identify a population with a high prevalence of C. trachomatis.

Adolescent↗
PubMed1985

Microbiology of the lower genital tract in postmenarchal adolescent girls: differences by sexual activity, contraception, and presence of nonspecific vaginitis.

The prevalence of selected microorganisms in the lower genital tract in postmenarchal adolescent girls was assessed, including vaginal Gardnerella vaginalis, group B streptococcus, lactobacillus, Mycoplasma species, Ureaplasma urealyticum, Staphylococcus aureus, and yeast, and endocervical Mycoplasma species, U. urealyticum, Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. Specific attention was focused on important sexually transmitted disease organisms, and differences in isolations by age, sexual activity, ethnicity, contraception, and the diagnosis of nonspecific vaginitis were measured. Sexually active subjects had a mean of 6.05 organisms (SD = 3.16), compared with 3.12 organisms (SD = 3.92) in non-sexually active subjects (P = 0.001). Sexually active subjects had significantly more vaginal G. vaginalis, lactobacilli, Mycoplasma species, and U. urealyticum, as well as endocervical Mycoplasma species and U. urealyticum, compared with non-sexually active subjects; C. trachomatis, N. gonorrhoea, and T. vaginalis were isolated exclusively from the sexually active group. Significant differences in isolation rates by ethnicity were found in vaginal Mycoplasma species and U. urealyticum, and endocervical Mycoplasma species, U. urealyticum, C. trachomatis, N. gonorrhoeae, and T. vaginalis. In general, organisms were isolated from blacks most frequently; N. gonorrhoea was isolated from blacks exclusively. Differences were found in microbiologic isolations by the presence or absence of nonspecific vaginitis. Vaginal G. vaginalis and Mycoplasma species and endocervical Mycoplasma species and U. urealyticum were found significantly more often in isolates from the group with nonspecific vaginitis. It is important to define the microbial flora of the lower genital tract in adolescent girls in order to understand its role in the pathogenesis of acute salpingitis.

Adolescent↗
PubMed1984

Screening for Chlamydia trachomatis and Neisseria gonorrhoeae in adolescent males: value of first-catch urine examination.

50 adolescent males attending a general teen clinic (aged 13-21) were evaluated for urethritis. After examination of sediment from the initial 15-20 ml of voided urine, first-catch urine (FCU), specimen urethral swabs were taken for culture of Chlamydia trachomatis and Neisseria gonorrhoeae. 21 of 23 (91%) males with greater than 10 leucocytes per high-power field of resuspended sediment (FCU-positive) had positive urethral cultures for C trachomatis or N gonorrhoeae compared with only 1 of 27 (4%) FCU-negative subjects (p less than 0.001). 12 of 22 culture-positive subjects had no genitourinary symptoms and 11 of the 12 had C trachomatis infections. The sensitivity of FCU examination in identifying culture-positive urethritis was 95%, the specificity 93%, and the predictive value of a positive FCU 91%. FCU examination is a useful, noninvasive screening test to detect urethritis associated with C trachomatis and N gonorrhoeae. The test may be especially helpful in identifying symptom-free males with chlamydia-associated urethritis.

Adolescent↗
PubMed1984

Blood volume expansion among blacks: an hypothesis.

Black persons are believed to have developed in a tropical environment and an expanded blood volume would have facilitated adaptation to such an environment. Throughout most of the first half of the life cycle blacks have slower heart rates than whites, and several lines of evidence suggest that heart rate is inversely related to blood volume. Review of blood volume studies in normotensive whites and normotensive blacks does not permit any conclusion concerning the blood volume hypothesis. Among patients with hypertension results of blood volume studies are inconsistent, but indirect evidence suggests that black patients with hypertension have greater plasma volume expansion than white patients with hypertension.

Adaptation, Physiological↗
PubMed1984

Chlamydia trachomatis: important relationships to race, contraception, lower genital tract infection, and Papanicolaou smear.

Chlamydia trachomatis is a common cause of sexually transmitted disease in adolescent girls. Of 366 adolescent patients screened, 15.3% were found to have chlamydial endocervical infections, with an infection rate of 23.3% in blacks, 14.3% in Hispanics, and 10.3% in whites (P = 0.01, excess for blacks). Of Chlamydia-positive patients, 63.6% had a diagnosis of lower genital tract infection, compared with 35.4% of Chlamydia-negative patients (P = 0.004). Oral contraceptive users had a higher prevalence of infection (23.8%) compared with those using a barrier method (16.2%) or with nonusers (9.3%) (P = 0.004). Inflammatory changes on Papanicolaou smears were associated with chlamydial infection (P = 0.0001). Other variables identified as risk factors for chlamydial infection included both a younger age at first intercourse (P = 0.02) and more years of sexual activity (P = 0.02). Chronologic, menarchal, and gynecologic age, biologic age of the cervix, the number of sexual partners in the last month and during a lifetime, and parity were not found to be associated with recovery of Chlamydia.

Chlamydia Infections↗
PubMed1984

Ultrastructure of Chlamydia trachomatis infection of the mouse oviduct.

Chlamydial inclusions were found in the luminal epithelium of all segments of the oviducts (ostium, ampulla, and isthmus) of mice experimentally inoculated with the mouse pneumonitis (MoPn) biovar of Chlamydia trachomatis. Electron microscopy of infected oviducts revealed chlamydial inclusions in both ciliated and nonciliated cells of the oviduct epithelium. Inclusions contained typical elementary, intermediate and reticulate bodies as well as numerous "miniature reticulate bodies" and membrane ghosts. Small, vesicle-like structures were observed in infected cells near inclusions but were not seen in apparently uninfected cells nor in the oviducts of mice inoculated with the control (sterile tissue culture supernate) suspension. Chlamydia-like particles were seen in vacuoles of polymorphonuclear leukocytes. Intracellular Chlamydia-like particles were not seen in any other cell type in the mouse oviduct. Infection of the mouse oviduct with MoPn is a convenient model for the study of C. trachomatis morphology in vivo.

Animals↗
PubMed1984

Cellular immunity to the mouse pneumonitis agent.

During infection with the mouse pneumonitis biovar of Chlamydia trachomatis, heterozygous (nu/+) mice with relatively intact T cell function develop both delayed hypersensitivity to C trachomatis antigen and antigen-specific lymphocyte transformation, whereas athymic nude (nu/nu) mice do not. Nu/nu mice are protected against death from mouse pneumonitis by transfer of immune T cells from nu/+ mice, which are more resistant to C trachomatis. While this enables athymic mice to make antibody to C trachomatis (which does not occur without reconstitution), resistance correlates best with development of antigen-specific lymphocyte transformation in the recipient animals. During infection nu/+ mice develop activated alveolar macrophages (by both morphological and functional criteria) while nu/nu mice do not. Nu/+ mice that have been preinfected with Histoplasma capsulatum to activate cellular immunity become more resistant to C trachomatis than do nu/+ controls. Cell-mediated immunity to C trachomatis pneumonia is T cell dependent and is important in host defense.

Animals↗
PubMed1984

A collaborative study of patient-initiated treatment of recurrent genital herpes with topical acyclovir or placebo.

Patient-initiated treatment of recurrent genital herpes with topical acyclovir was compared with placebo treatment in a multicenter collaborative trial involving 309 patients. No differences were found between the group using acyclovir and that using placebo except that herpes simplex virus was excreted for a shorter period by women using acyclovir. This difference was partially accounted for by the fact that some patients whose viral culture results subsequently proved positive began to use their medication before lesions formed. One hundred patients initially applied ointment within 6 hr of onset of the prodrome and before actual lesion formation. Separate analysis of this group showed a diminished duration of viral excretion by women using acyclovir and a reduced interval between lesion formation and total crusting in men using acyclovir, but both differences were of only borderline significance (.05 less than P less than .10). The results indicate that patient-initiated therapy with topical acyclovir in polyethylene glycol exerts no clinically significant effect on recurrent genital herpes.

Acyclovir↗
PubMed1984

Blood pressure during the first five years of life: relation to ethnic group (black or white) and to parental hypertension.

Blood pressure was measured in 392 healthy, full-term, appropriate-weight infants and was measured again at 6, 15, 24, 36, 48, and 60 months of age. Systolic pressure rose from birth to six months of age, remained at a plateau until 15 months of age, and from 24 to 60 months rose an average of 1 mmHg per year. Diastolic pressure rose from birth to 24 months but showed little change from 24 to 60 months. The correlation of systolic with diastolic pressure decreased seriatim from birth to 60 months. Blood pressure did not vary as a function of ethnic group, sex, or socioeconomic status during the first five years of life. The association of body size with blood pressure was no more than modest during this period, but seemed to be closer for females than for males. A closer child-parent association was found for heart rate than for blood pressure. The child's heart rate was inversely associated with the parent's blood pressure although the child's blood pressure was not associated with the parent's pressure. During the first five years of life, a low heart rate may be a more significant risk factor for adult hypertension than elevated blood pressure.

Aging↗
PubMed1984

Heart rate during the first five years of life: relation to ethnic group (black or white) and to parental hypertension.

Heart rate was measured in 392 healthy, full-term, appropriate-weight infants and was measured again at 6, 15, 24, 36, 48, and 60 months of age. Heart rate increased from newborn to six months of age and then decreased seriatim. Heart rate did not vary as a function of socioeconomic status or of sex. Blacks had higher heart rates than whites as newborns and at six months of age; at the older ages the difference was no longer significant. The slowing of heart rate with age was greater among blacks. Heart rate was inversely associated with weight and with height, but showed no association with blood pressure. A significant child-mother correlation of heart rate was found at two ages. No significant child-mother correlations of systolic or of diastolic blood pressure were found. Thus, a closer child-parent association was found for heart rate than for blood pressure. Offspring of a parent with a history of hypertension had slower heart rates than offspring neither of whose parents had a history of hypertension. Neither the child's systolic nor diastolic blood pressure varied with the presence or absence of a parental history of hypertension. Results suggest that during the first five years of life a child's slower heart rate may be a better index of risk of adult hypertension than a child's elevated blood pressure.

Aging↗
PubMed1984

Role of disulfide bonding in outer membrane structure and permeability in Chlamydia trachomatis.

The outer membrane of Chlamydia trachomatis can be efficiently solubilized by a variety of mild detergents in the presence of the reducing agent dithiothreitol. This allows purification of the chlamydial major outer membrane protein at high yield in very gentle conditions by using its differential solubility in Sarkosyl and octylglucoside in the presence of dithiothreitol. The major outer membrane protein of the L2 serovar is an acidic protein with a pI of ca. 5. It contains three cysteine residues that allow it to form a disulfide-linked proteinaceous network responsible for the characteristic rigid outer membrane of the elementary body. By the use of an in vitro reconstitution assay developed by Nikaido and his co-workers, it was shown that the outer membrane contains pores with an "exclusion limit" between molecular weights 850 and 2,250. In addition, the "opening-closing" of the pores was shown to be controlled through a simple reduction-oxidation mechanism. A model that outlines the role of disulfide bonding in the physiology of chlamydial development is presented.

Amino Acids↗
PubMed1984

Effect of bacterial secondary infection in an animal model of trachoma.

In trachoma the interaction between chronic chlamydial and acute bacterial conjuntivitis has been suggested as important in determining the severity of disease and, therefore, blindness. We investigated the effect of acute conjunctival infection with each of three common human pathogens, Haemophilus influenzae, Haemophilus aegyptius , and Streptococcus pneumoniae, in a model of trachoma established in cynomolgus monkeys. Although acute conjunctivitis developed, animals with trachoma were not more susceptible to infection than other monkeys, nor did they develop more severe disease as a result of the bacterial conjunctivitis. The failure of bacterial conjunctivitis to exacerbate the experimental trachoma indicates that, in this model at least, chronically maintained chlamydial infection alone is sufficient to produce the changes characteristic of trachoma.

Animals↗
PubMed1984

Antibody in host defense against mouse pneumonitis agent (murine Chlamydia trachomatis).

In a murine model of chlamydial pneumonia employing murine Chlamydia trachomatis, immune serum given intranasally delayed death in nude (nu/nu) mice and prevented death in nu/+ mice. Serum-derived immunoglobulin G and A fractions and immune lavage fluid fractions containing immunoglobulins G and A were effective in producing protection when used to opsonize the murine C. trachomatis inoculum. In hyperclean mice (previously made germfree and then colonized with a limited flora nonpathogenic to mice) antibody given intravenously was ineffective. The effects of antibody and nonspecific stimulation of cell-mediated immunity (after previous infection with Histoplasma capsulatum) were additive in increasing host resistance to murine C. trachomatis.

Animals↗
PubMed1984

Enzyme immunoassay for diagnosis of gonorrhea.

An enzyme immunoassay (EIA; Gonozyme [Abbott Laboratories]) for gonococcal antigen was assessed for the rapid diagnosis of gonorrhea. Patients attending two sexually transmitted disease clinics were tested by EIA and culture on Thayer-Martin medium. EIA was highly effective in detecting gonococcal infection among symptomatic men, with 70 of 75 (93.3%) culture-positive men having positive tests and no false-positive reactions. The performance of the test was not as good in detecting cervical gonorrhea; the best result obtained was a sensitivity of 87% (33 of 38) for EIA compared with culture. EIA false-positives occurred at a relatively low rate for women, with the test having a specificity of ca. 97%. The test clearly is capable of detecting gonococcal antigen in cervical and urethral specimens, but its role in routine diagnosis is not clear. Its performance seems equal to that of the Gram stain for men, but it seems to be less sensitive than culture for cervical gonorrhea--a drawback in high-risk populations. The low false-positive rate could be an important issue in screening low-prevalence populations.

Antigens, Bacterial↗