Gene duplication of zebrafish JAK2 homologs is accompanied by divergent embryonic expression patterns: only jak2a is expressed during erythropoiesis.

Members of the JAK family of protein tyrosine kinase (PTK) proteins are required for the transmission of signals from a variety of cell surface receptors, particularly those of the cytokine receptor family. JAK function has been implicated in hematopoiesis and regulation of the immune system, and recent data suggest that the vertebrate JAK2 gene may play a role in leukemia. We have isolated and characterized jak cDNAs from the zebrafish Danio rerio. The zebrafish genome possesses 2 jak2 genes that occupy paralogous chromosome segments in the zebrafish genome, and these segments conserve syntenic relationships with orthologous genes in mammalian genomes, suggesting an ancient duplication in the zebrafish lineage. The jak2a gene is expressed at high levels in erythroid precursors of primitive and definitive waves and at a lower level in early central nervous system and developing fin buds. jak2b is expressed in the developing lens and nephritic ducts, but not in hematopoietic tissue. The expression of jak2a was examined in hematopoietic mutants and found to be disrupted in cloche and spadetail, suggesting an early role in hematopoiesis. Taken together with recent gene knockout data in the mouse, we suggest that jak2a may be functionally equivalent to mammalian Jak2, with a role in early erythropoiesis.

Screening women for gonorrhea: demographic screening criteria for general clinical use.

OBJECTIVES: The purpose of this analysis was to derive potential gonorrhea screening criteria for women. METHODS: Data corresponding to 44,366 gonorrhea cultures from women 15 through 44 years of age in Columbus, Ohio, were analyzed. RESULTS: Characteristics that were associated with gonococcal infection and were suitable for screening decisions included patient's age and marital status and previous prevalence of gonorrhea at provider site. Probabilities of infection ranged from .001 for married women 25 through 44 years of age at low-prevalence provider sites to .078 for unmarried women 15 through 19 years of age at high-prevalence sites. CONCLUSIONS: Patient's age and marital status and prevalence of gonorrhea at provider site can be used as indicators to ensure testing of high-prevalence groups.

Trends in the prevalence of chlamydial infections. The impact of community-wide testing.

BACKGROUND: Evaluation of existing testing programs should guide the national effort to expand programs for the prevention of chlamydial infections. The Columbus (Ohio) Health Department instituted community-wide testing for Chlamydia trachomatis in 1988. GOALS: To assess trends in the prevalence of chlamydial infection, the coverage of screening, and concurrent trends in the prevalence of gonorrhea. STUDY DESIGN: This was a cross-sectional study of women 15 to 44 years of age tested for C. trachomatis at over 50 provider sites in Columbus, Ohio, from 1989 to 1992. RESULTS: The prevalence of chlamydial infection among all women tested decreased by 33% from 1989 to 1992. Prevalence decreased least (19%) among black women 15 to 19 years of age, the group with the highest initial prevalence (20.2%), even though 42% of this population in the city was tested. Prevalence did not decrease at all among prenatal patients 15 to 19 years of age. For women tested for both gonorrhea and chlamydia, gonorrhea decreased by 39% during the 4-year period. CONCLUSIONS: Screening appeared to have limited effect on the prevalence of chlamydial infection for groups with highest initial prevalence, despite the relatively high percentage of the population tested. Expanding screening programs to include men and instituting behavioral interventions may be necessary to reduce more rapidly the prevalence of chlamydia among these women.

Detection of herpes simplex virus by the Kodak SureCell Herpes Test.

The Kodak SureCell Herpes Test Kit (SC-HSV) was evaluated in a high-risk sexually transmitted disease clinic population. A total of 97 lesion specimens (from 94 patients) were tested for the presence of herpes simplex virus by SC-HSV and by spin-amplified tissue culture confirmed by an enzyme immunoassay. The overall sensitivity of SC-HSV compared with that of spin-amplified tissue culture-enzyme immunoassay was 81.1%; the specificity was 100%. For vesicular lesions only, SC-HSV sensitivity was 100%; for nonvesicular lesions, sensitivity was 75.6%, SC-HSV was rapid (less than 15 min) and very easy to perform.

Establishing Chlamydia trachomatis isolation capability in a local laboratory.

A system for the culture and identification of Chlamydia trachomatis was established in a local health department laboratory. The McCoy cell-cycloheximide procedure was adopted with use of on-site monolayer production and iodine staining. Several procedural modifications were analyzed for sensitivity, including two-vial vs. one-vial inoculation, overnight refrigeration vs. immediate inoculation of the monolayer, and use of transport media with vancomycin (100 micrograms/ml) vs. transport media without vancomycin. Costs associated with establishing and maintaining this procedure over a one-year period were documented. Inoculation of two monolayers improved sensitivity only slightly (87/292 vs. 85/292). Loss in sensitivity following overnight refrigeration of the sample was approximately 7%; 42 of 45 positive cultures were detected. Addition of 100 micrograms of vancomycin/ml to the transport media increased apparent sensitivity from 27.4% to 29.6% among females with gonorrhea. The cost was $.06 per culture. On the basis of this information, cultures for isolation of C. trachomatis are now offered to our clinic for sexually transmitted diseases as well as to some private physicians and clinics. We are using one-vial inoculation of a specimen transported in sucrose-phosphate buffer containing 100 micrograms vancomycin/ml. The specimen is either cultured immediately or snap frozen at -77 C.

Cell wall composition and associated properties of methicillin-resistant Staphylococcus aureus strains.

Methicillin-resistant (MR) Staphylococcus aureus strains have previously been reported to be deficient in surface negative charge; this has been correlated with methicillin resistance and ascribed to a deficiency of teichoic acid at the cell surface (A. W. Hill and A. M. James, Microbios 6:157-167, 1972). Teichoic acid was present in walls of MR organisms as revealed by appreciable phosphate levels and detection of ribitol residues. Phosphate levels in walls from five MR strains (0.54 to 0.77 mumol/mg of wall) were lower than in three unrelated methicillin-sensitive (MS) strains (0.86 to 1.0 mumol/mg of wall). However, two MS strains derived from two of the MR strains had wall phosphate levels very similar to those of the MR strains. No evidence for unusual wall polymers was found. Simple deficiency of wall teichoic acid does not result in methicillin resistance since an independently isolated teichoic acid-deficient strain (0.1 mumol of phosphate per mg of wall) was not methicillin resistant. In studies of biological properties possibly related to wall teichoic acid, it was discovered that walls isolated from MR organisms grown in the presence of methicillin autolyzed more rapidly than those isolated from organisms grown in the absence of the drug. Since methicillin resistance is enhanced by NaCl and suppressed by ethylenediaminetetraacetate, the effects of these compounds on autolysis of isolated walls were studied. NaCl (1.0 M) and ethylenediaminetetraacetate (1.0 mM) inhibited the autolysis of walls isolated from MR and MS strains. An MR strain bound phage 47, 52A, and 3A only slightly less well than their respective propagating strains.