Prospective study of high grade anal squamous intraepithelial neoplasia in a cohort of homosexual men: influence of HIV infection, immunosuppression and human papillomavirus infection

OBJECTIVE: To determine the risk of developing high grade anal squamous intraepithelial neoplasia (HG-AIN) in relation to HIV infection and immunosuppression, after controlling for the effects of human papillomavirus (HPV) infection. DESIGN: Prospective cohort study of 158 HIV-seropositive and 147 HIV-seronegative homosexual men presenting to a community-based clinic with initially negative anal cytologic and colposcopic findings. METHODS: Subjects completed self-administered questionnaires, underwent cytologic screening, and standardized unaided and colposcopic examination of the proximal anal canal for presence of abnormalities suggestive of AIN. Anal specimens were screened for HPV DNA. RESULTS: HG-AIN developed in eight (5.4%) and 24 (15.2%) HIV-seronegative and -seropositive men, respectively. Risk of HG-AIN among HIV-seronegative men was associated with detection of anal HPV types 16 or 18 by Southern transfer hybridization (STH), detection of HPV 16 or 18 at the lower levels by polymerase chain reaction but not by STH, and with number of positive HPV tests; HG-AIN risk among HIV-seropositive men was associated with detection of HPV 16 or 18 only by STH, detection of HPV types other than 16 or 18, CD4 count < or = 500 x 10(6)/l, and number of positive HPV tests. HIV-induced immunosuppression remained an independent predictor of HG-AIN after adjusting for type and level of detection of HPV; HIV infection predicted HG-AIN risk after adjustment for number of positive HPV tests. CONCLUSIONS: The association of HG-AIN with HIV, independent of HPV type, level of HPV detection and number of positive HPV tests, suggests that this increased risk cannot be entirely explained by an effect of HIV on HPV detection. Future studies focusing on factors more specific to the local microenvironment in the anal canal should help clarify these issues.     

Outcome of plasma exchange therapy in thrombotic microangiopathy after renal transplantation

Thrombotic microangiopathy (TMA) in renal transplant recipients is commonly associated with calcineurin inhibitors (CNIs), though several factors such as vascular rejection, viral infections and other drugs may play a contributory role. We report a series of 29 patients with TMA, all of whom were on CNIs. Though plasma exchange (PEx) is widely used to treat TMA, therapeutic guidelines are not well defined. All our patients were treated with PEx and discontinuation of CNIs. Thrombotic microangiopathy was diagnosed at a median of 7 days post-transplant. The mean decrease in Hgb and platelets during TMA was 66% and 64%, respectively, and peak serum creatinine during TMA was 7.4 +/- 2.9 mg%. Mean duration of PEx therapy was 8.5 (range 5-23) days. Recovery of platelet count to 150K/mcL and Hgb to 8-10 g/dL were used as endpoints for PEx. Twenty-three/29 (80%) patients recovered graft function after PEx. Twenty/23 (87%) patients who recovered were placed back on CNl. Nineteen/20 (95%) patients tolerated reinstitution of CNl without recurrence of TMA. In post-transplant TMA, PEx was associated with a graft salvage rate of 80%, reversal of hematological changes can be used as the endpoint for PEx therapy and CNl can be reintroduced without risk of recurrence in the majority of patients.     

Determination of uranium in fertilisers using fission track method

Trace contents of uranium in various commercial fertilizers e.g. ureas, superphosphates, diammonium phosphates have been determined using fission track etch technique. The uranium content in ureas varies from .05 to 1.3 mg kg^–1 whereas in superphosphates it varies linearly with phosphate content.