Virologic, immunologic, and clinical parameters in the incidence and progression of anal squamous intraepithelial lesions in HIV-positive and HIV-negative homosexual men.

Anal cancer may be preceded by anal squamous intraepithelial lesions (ASIL), but the natural history of ASIL is poorly understood. In this report, we characterize the 2-year incidence and progression of low-grade SIL (LSIL) and high-grade SIL (HSIL) in a cohort study in 346 HIV-positive and 262 HIV-negative homosexual or bisexual men. Subjects were studied at defined intervals using anal cytology, anoscopy with biopsy of visible lesions, human papillomavirus (HPV) testing, HIV serostatus, CD4 level, and data on medical history and lifestyle. The incidence of HSIL within 2 years was 20% in HIV-positive men and 8% in HIV-negative men who were normal at baseline. In total, 62% of HIV-positive and 36% of HIV-negative men with LSIL at baseline progressed to HSIL. The relative risk (RR) for anal disease progression in HIV-positive men was 2.4 (95% confidence interval [CI], 1.8-3.2) when compared with HIV-negative men. The RR increased to 3.1 (95% CI, 2.3-4.1) in HIV-positive men with CD4 counts <200/mm3. Infection with multiple HPV types was a risk factor for anal disease progression in both HIV-positive (RR = 2.0; 95% CI, 1.0-4.1) and HIV-negative (RR = 5.1; 95% CI, 2.3-11) men. The incidence of anal HSIL and progression of LSIL to HSIL within 2 years of follow-up is high in HIV-positive homosexual or bisexual men and to a lesser extent, in HIV-negative men. Men with the above risk factors may be at increased risk of developing anal cancer.

Anal squamous intraepithelial lesions in HIV-positive and HIV-negative homosexual and bisexual men: prevalence and risk factors.

Anal cancer is more commonly found in homosexual and bisexual men than cervical cancer is in women. Invasive anal cancer may be preceded by anal squamous intraepithelial lesions (ASIL), and treatment of ASIL may prevent the development of anal cancer. We characterized the prevalence and risk factors for ASIL in 346 HIV-positive and 262 HIV-negative homosexual men. Anal cytology, biopsy of visible anal lesions, and human papillomavirus (HPV) tests were performed, and data on HIV serostatus, CD4 count, and medical and lifestyle history were collected. ASIL was diagnosed in 36% of HIV-positive men and 7% of HIV-negative men (relative risk [RR] = 5.7; 95% confidence interval [CI], 3.6-8.9). Among HIV-positive men, the RR for ASIL increased with lower CD4 levels but was elevated even in men with CD4 levels >500/mm3 (RR = 3.8; 95% CI, 2.1-6.7) when compared with HIV-negative men. High-level HPV infection, as measured by detection of both hybrid capture (HC) group A and group B types, was another significant risk factor for ASIL in both HIV-positive men (RR = 8.8; 95% CI, 2.3-35) and HIV-negative men (RR = 20; 95% CI, 5.5-71) when compared with HC-negative men. HIV-negative men with anal HPV infection and HIV-positive men, regardless of CD4 level, are at high risk for ASIL.

Effect of dietary sodium bicarbonate and magnesium oxide on production and physiology in early lactation.

Twenty cows were in an experiment to measure effects of dietary buffers, sodium bicarbonate and magnesium oxide, on ration adjustment and incidence of metabolic problems in the first 8 wk postpartum. Cows were fed 2.7 kg grain per day and alfalfa ad libitum prepartum and switched immediately to a complete ration of 40% corn silage and 60% concentrate (dry matter) postpartum. Treatments included 1.5% sodium bicarbonate and .8% magnesium oxide (total ration dry matter) fed in a 2 x 2 factorial arrangement. Cows receiving bicarbonate peaked 2 to 3 wk earlier in intake and averaged 2.1 kg per day greater intake than those fed the control diet. Actual milk production was increased by sodium bicarbonate with greatest differences for cows receiving both buffers averaging 3.8 kg per day more milk than control cows. Increases over co ntrols were 2.6 and 5.6 kg fat-corrected milk per day for cows receiving sodium bicarbonate alone or in combination with magnesium oxide, respectively. Sodium bicarbonate increased acetate to propionate molar ratios in rumen samples taken at 1 and 2 wk postpartum whereas neither buffer had any effect on rumen pH. Blood hematocrit and urine pH were not affected by treament. Magnesium oxide increased fecal pH .8 units and slightly decreased fecal starch, but sodium bicarbonate had no effect.

Clinical evaluation of methods of treatment.

Veterinary clinicians can make a significant contribution to the knowledge of the practical value of using alternative treatment methods by conducting clinical trials. By following a logical sequence of steps the clinician can design and participate in a clinical trial in his clinic without interfering with his normal practice. The successive stages of a field trial were presented along with an example to demonstrate the application of the principles involved. These stages are: design and planning, implementation, collection of data, and analysis of data.The veterinary clinician who initiates clinical trials to answer questions plaguing him provides two services to the veterinary profession. First, he helps answer questions facing private practitioners throughout the profession. Second, he can demonstrate that not all research must be done in a laboratory setting isolated from "real world" complications. Seeing the results that can be derived from individual practicing veterinarians participating in clinical trials should act as a stimulus to other veterinarians to logically organize the data coming from their practices.