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Biomedical subjects

J Schachter

Publications and source records attributed to J Schachter.

At least 289 records · Page 16Linked to original sources

Failure of serology in diagnosing chlamydial infections of the female genital tract.

Chlamydia trachomatis was recoved from 20% (36/180) of women attending a venereal disease clinic. All infected women had chlamydial antibodies in their serum and cervical secretions. However, the background rates of chlamydial antibody in chlamydia-negative women were very high. Measurement of antibodies in serum (complement fixation or immunoglobulin G [IgG] and IgM by microimmunofluorescence) or cervical secretion (IgG, IgM, IgA or secretory IgA classes) did not result in predictive values of greater than 32%. It is concluded that the detection of chlamydial antibodies in serum or cervical secretions cannot be substituted for agent isolation in diagnosing these infections.

Antibodies, Bacterial↗

Purulent ocular discharge in neonates: significance of Chlamydia trachomatis.

We obtained cultures for bacteria and chlamydiae from 100 infants with conjunctivitis that began during the first month of life. Sixty-nine infants were evaluated during well-child visits (group A); 31 were seen specifically for the ocular discharge (group B). Potentially pathogenic bacteria, predominantly Staphylococcus aureus, were cultured from one third of the infants in each group. Chlamydia trachomatis was recovered from three infants (4%) in group A and from ten (32%) in group B. Three infants with chlamydial conjunctivitis (two in group A, one in group B) had only mild inflammation. Initial treatment with topical antibiotics was unsuccessful in eliminating the organism from seven of 11 infants.

Conjunctivitis↗

Psittacosis: the reservoir persists.

During a one-year period, 101 parakeets and parrots were submitted for laboratory examination. The birds were sick, dead, or from premises where morbidity had been observed. Tissue specimens from these birds were tested for the presence of Chlamydiapsittaci by two methods. A tissue culture system using McCoy cells treated with 5-iodo-2-deoxyuridine was found to be more sensitive than intraperitoneal inoculation of mice for isolation of the chlamydiae. Chlamydiae were recovered from 21 (34%) of 61 parakeets and 16 (40%) of 40 parrots tested. This high rate of infection persists despite the availability of effective chemotherapeutic regimens for control of chlamydial infection in psittacines. The origins of some of the infected birds were traced to aviaries where subsequent treatment with chlortetracycline was successful in eradication of the chlamydial infection. Other infected birds had been imported recently and could be traced back to quarantine centers where (by law) the birds received chemoprophylaxis for chlamydial infection. Our results suggest that this program is an administrative failure.

Animals↗

The use of cycloheximide-treated cells for isolating trachoma agents under field conditions.

Standard procedures for the isolation of Chlamydia trachomatis require pretreatment of the tissue culture cells. We evaluated the use of cycloheximide, an antimetabolite that can be added to the cells with the inoculum. Cycloheximide-treated cells provided a sensitive system for isolating trachoma agents. This system was applicable to field studies as requirements for equipment were minimal and the cells were 2 weeks old when inoculated.

Chlamydia trachomatis↗

Staphylococcal infection superimposed on guinea pig inclusion conjunctivitis.

We have studied the effect of superimposed staphylococcal infection on guinea pigs who had inclusion conjunctivitis. Although the acute phase of the inclusion disease was slightly more intense in the superinfected group, the course and duration were unaltered. We did not find any reactivation of the inclusion disease from the subconjunctival injection of glucocorticoid.

Acute Disease↗

Antibiotic susceptibility of Chlamydia trachomatis.

The antibiotic susceptibility of Chlamydia trachomatis isolates was determined in a tissue culture system. Representatives of all currently recognized serotypes of trachoma-inclusion conjunctivitis agents were tested. Tetracycline and erythromycin yielded similar results, with 1.0 mug/ml preventing chlamydial replication. Rifampin was the most active antibiotic, with 0.25 mug/ml completely suppressing inclusion formation of all strains. Fifty percent end points were usually achieved at one-fourth to one-eighth the 100% suppression level. Penicillin was not as effective, and the assays were often irregular. Antibiotic susceptibility of these chlamydiae was essentially the same, regardless of serotype, anatomic site infected, geographic origin, or antibiotic use in the community.

Chlamydia trachomatis↗

Resistance to reinfection with a chlamydial agent (guinea pig inclusion conjunctivitis agent).

Although most chlamydial infections are chronic or recurrent, infection of the guinea pig's eye with guinea pig inclusion conjunctivitis (GPIC) agent induces a marked resistance to reinfection. To characterize this resistance to GPIC agent, we compared the disease and infection in previously infected guinea pigs with that in animals infected for the first time. In animals experiencing primary infection, even the lowest dose (10 egg-lethal doses [ELD50]) produced the disease and chlamydial inclusions in conjunctival smears, but the incubation period became progressively shorter with the highest inocula (10(4) and 10(5) ELD50). In animals with previous infection only these two highest inocula produced disease and infection, but the disease was short-lived, and replication of the agent was severely limited. The mechanism of this resistance may be due to secretory antibody in the tears, cellular immunity, or other local factors.

Animals↗

Median age at onset of asthma and allergic rhinitis in Tecumseh, Michigan.

The ages at which allergies are likely to first become manifest is a subject of epidemiologic interest. The distribution of the onset ages reported in a population survey provides a distorted picture because it is a function of the age distribution of the population at the time of survey, and hence does not represent generational experience. A lifetable method is presented which transforms the raw cross-sectional data to a longitudinal basis. The information on onset age of asthma and allergic rhinitis collected in the 1962-1965 cycle of the Tecumseh Community Health Study is used to illustrate the method. The resultant distributions have median onset ages for the respective allergies which are considerably higher than those based on the onset frequency distributions of enumerated data.

Adolescent↗