Role of zidovudine antiretroviral therapy in the pathogenesis of acquired immunodeficiency syndrome-related lymphoma

The role of zidovudine and other antiretroviral agents in the pathogenesis of acquired immunodeficiency syndrome (AIDS)-related lymphomas has been somewhat controversial. In an attempt to elucidate the precise role of antiretroviral agents in the subsequent development of AIDS-related lymphoma, we performed a population-based, case-control study of human immunodeficiency virus (HIV)-seropositive patients with intermediate- or high-grade lymphoma in Los Angeles County, California, in which information regarding use of antiretroviral medications was ascertained. Diagnostic biopsy material was reviewed to confirm intermediate-or high-grade lymphoma. A structured interview, conducted with all cases and controls, included information about use of zidovudine and other antiretroviral agents. A total of 112 HIV-infected homosexual/bisexual men with lymphoma were matched to 112 homosexual/bisexual men with asymptomatic HIV infection; 49 of the lymphoma cases were also matched to 49 additional controls with AIDS, as defined by conditions other than lymphoma. Positive histories of zidovudine use were reported by 44 (39%) lymphoma cases, 24 (21%) asymptomatic HIV controls, and 21 (42%) AIDS controls. The average duration of zidovudine use up to 12 months before lymphoma diagnosis was 19.0 +/- 13.0 months (mean +/- SD) for the lymphoma cases, 12.6 +/- 10.5 months for the asymptomatic controls, and 11.0 +/- 7.1 months for the AIDS controls. When comparing the 49 HIV-positive lymphoma cases with their 49 matched AIDS controls, all of whom were diagnosed with AIDS during the same time period, the matched relative odds of lymphoma associated with prior use of zidovudine was 0.43 (95% confidence interval [CI] = 0.17 to 1.12). In comparing all 112 lymphoma cases with 49 AIDS controls, the unmatched relative odds of lymphoma associated with zidovudine use was 0.93 (95% confidence interval = 0.47 to 1.83). One lymphoma case and no AIDS control cases had a history of didanosine use; no lymphoma case or AIDS control cases had taken zalcitabine. We conclude that zidovudine is not associated with an increased risk of development of lymphoma among HIV-infected homosexual or bisexual men.     

Complex Partial Seizures: Cerebellar Metabolism

We used positron emission tomography (PET) with [18F]2-deoxyglucose to study cerebellar glucose metabolism (LCMRglu) and the effect of phenytoin (PHT) in 42 patients with complex partial seizures (CPS), and 12 normal controls. Mean +/- SD patient LCMRglu was 6.9 +/- 1.8 mg glucose/100 g/min (left = right), significantly lower than control values of 8.5 +/- 1.8 (left, p less than 0.006), and 8.3 +/- 1.6 (right, p less than 0.02). Only four patients had cerebellar atrophy on CT/MRI; cerebellar LCMRglu in these was 5.5 +/- 1.5 (p = 0.054 vs. total patient sample). Patients with unilateral temporal hypometabolism or EEG foci did not have lateralized cerebellar hypometabolism. Patients receiving phenytoin (PHT) at the time of scan and patients with less than 5 years total PHT exposure had lower LCMRglu, but the differences were not significant. There were weak inverse correlations between PHT level and cerebellar LCMRglu in patients receiving PHT (r = -0.36; 0.05 less than p less than 0.1), as well as between length of illness and LCMRglu (r = -0.22; 0.05 less than p less than 0.1). Patients with complex partial seizures have cerebellar hypometabolism that is bilateral and due only in part to the effect of PHT.     

Pilot study of a revised field work performance report rating procedure

Expressed dissatisfaction with the rating aspect of the Field Work Performance Report (FWPR) led to a study of the following proposed revisions: the present FWPR scale was extended by one point (from 4 to 5), the possible points were redefined quantitatively, and a qualitative factor was added. Both the present form and the revised form of the FWPR were administered to field work students from two schools to determine if these revisions would result in more effective and meaningful distributions of item scores and total scores. To make this determination, statistical analyses were employed and comments from participating clinical supervisors were invited. Findings indicated that the revised form dispersed scores more effectively and meaningfully. However, the analyses also pointed to the need for further revisions.     

Cimetidine inhibits burn edema formation

Large doses of cimetidine significantly inhibit edema formation in thermally injured rat skeletal muscle. Tissue sodium influx and potassium efflux is also sharply restricted. These effects were obtained even if the administration of cimetidine was delayed for up to 4 hours after injury, but no beneficial effect occurred if drug administration was delayed for 14 hours, when most of the edema had already accumulated. The minimal effective dose is between 0.1 to 0.2 mg/gm.