Antagonists to the Wnt cascade exhibit sex-specific expression in gonads of sexually mature shovelnose sturgeon.

Little is known regarding molecular mechanisms involved in sex determination and differentiation in sturgeon species. We addressed this knowledge gap by using next generation pyrosequencing technology to provide transcript libraries and species-specific sequences for mature gonads of shovelnose sturgeon, Scaphirhynchus platorynchus. We then mined these libraries to identify gender-specific transcripts and quantified relative transcript abundance using quantitative real-time polymerase chain reaction (qPCR). We detected a limited number of genes known to play a role in sex differentiation in other species. The sequence for dmrt1 was found only in the testes library. The abundance of dmrt1 differed slightly between the sexes, but the melt curve suggests that there may be different isoforms of dmrt1 in ovaries and testes of shovelnose sturgeon. The transcription factor foxl2 was 5.3-fold greater in ovaries than in testes. Two antagonists to the Wnt cascade, dickkopf-1 (dkk1) and dapper-1 (dact1), were found only in the ovary library. Results from qPCR indicated that dkk1 and dact1 were upregulated 1,819.1- and 207.5-fold, respectively, in ovaries compared with testes. These results suggest that antagonists to the Wnt cascade may play significant roles in sex differentiation and gonadal development in sturgeon and could serve as sex markers in this group of ancient fish.

CD4 lymphocyte counts within 24 months of human immunodeficiency virus seroconversion. Findings in the US Navy and Marine Corps. The Navy Retroviral Working Group.

BACKGROUND: Although CD4 lymphocytes are the primary target of the human immunodeficiency virus (HIV), few studies have evaluated CD4 cell counts in a large population of seroconverters with known dates of seroconversion. This study reports an analysis of CD4 lymphocyte counts and CD4 cells as a percentage of all lymphocytes within 24 months of estimated date of HIV seroconversion in 1046 HIV seroconverters. METHODS: Study participants included all Navy and Marine Corps seroconverters (1023 men, 23 women) from 1987 through 1991 with a previous negative HIV test. CD4 lymphocyte counts and percentages were obtained for blood drawn from HIV seroconverters during initial clinical evaluations carried out at Naval Medical Centers in Bethesda, Md; Oakland, Calif; Portsmouth, Va; and San Diego, Calif. The seroconversion date was estimated as the midpoint between the last negative test date and the first positive test date. RESULTS: Nearly 40% of seroconverters presented with initial CD4 lymphocyte counts lower than 0.50 x 10(9)/L (500/microL) and 3% with counts lower than 0.20 x 10(9)/L (200/microL). Approximately half the seroconverters presented with fewer than 29% CD4 cells, and 5% presented with fewer than 14% CD4 cells. There were no significant differences in CD4 counts according to sex, race, or estimated duration of HIV infection. CONCLUSIONS: Little difference in CD4 lymphocyte counts or percentages by duration of infection within 24 months was evident on initial clinical evaluation of HIV seroconverters. The high percentage of seroconverters presenting with low CD4 counts or percentages suggests a population of seroconverters with rapid depletion of CD4 lymphocytes following seroconversion.

Initial low CD4 lymphocyte counts in recent human immunodeficiency virus infection and lack of association with identified coinfections.

Initial CD4 lymphocyte counts were studied in 244 patients with human immunodeficiency virus (HIV) seroconversion. The CD4 cell counts at initial presentation after seroconversion were normally distributed (mean, 579/mm3; SD, 252). The mean percentage of CD4 cells was 26.1% (SD, 5.6). CD4 cell counts were < 500/mm3 in 41% and < 200/mm3 in 4%. The mean calculated duration of HIV infection was 7.7 months, which was not significantly different between the highest and lowest CD4 count quartiles (8.1 vs. 7.9). Age, sex, race, and serologic evidence of toxoplasmosis, cytomegalovirus, hepatitis B, syphilis, and varicella-zoster virus were not associated with initial low CD4 cell counts; however, never-married men were significantly overrepresented in the lowest quartile. These findings suggest that extensive CD4 lymphocyte depletion is common in early HIV infection and that frequent screening is necessary to identify newly infected patients who would benefit from antiretroviral therapy.