The effect of tolerance on opiate dependence as measured by the adenylate cyclase rebound response to naloxone in the NG108-15 model system

The naloxone-induced adenylate cyclase rebound response produced by opiates in the NG108-15 cells is quite apparent after 48 h treatment with M but it is undetectable after incubation with the high intrinsic activity agonist etorphine. Replacement of agonists by antagonists in receptors that have been rendered inactive by tolerance does not elicit the AC rebound response, which is considered a biochemical correlate of dependence. This indicates that marked tolerance and receptor down-regulation induced by prolonged treatment with high efficacy agonists may reduce the level of dependence.     

Management of agitation, aggression, and psychosis associated with dementia: a pooled analysis including three randomized, placebo-controlled double-blind trials in nursing home residents treated with risperidone

This analysis used pooled data from three randomized, placebo-controlled trials that examined the efficacy and safety of risperidone for the treatment of agitation, aggression, and psychosis associated with dementia in elderly nursing home residents to assess the risk-benefit of the use of risperidone in this population.

The efficacy data (risperidone n = 722, placebo n = 428) were obtained from the Cohen-Mansfield agitation inventory (CMAI) and behavioral pathology in Alzheimer's disease (BEHAVE-AD) total and subscales. Additionally, clinical global impression (CGI) assessments were performed. Subgroup analyses were performed by type of dementia, severity of dementia, presence or absence of somnolence as an adverse event, and presence or absence of psychosis at baseline. Safety assessments included evaluation of treatment emergent adverse events, Extrapyramidal Symptom Rating Scale, ECG and vital signs, and Mini-Mental State Examination (MMSE). The mean dose of risperidone at end point was 1.0 mg/day (0.02 S.E.).

The observed mean change at end point was significantly higher for risperidone than for placebo on CMAI total score (−11.8 versus −6.4, respectively; p < 0.001), total aggression score (−5.0 versus −1.8, respectively; p < 0.001), BEHAVE-AD total score (−6.1 and −3.6, respectively; p < 0.001), and psychotic symptoms score (−2.1 and −1.3, respectively; p = 0.003). The main treatment effects of risperidone were similar in all subgroup analyses. Additionally, risperidone-treated patients scored significantly better than placebo-treated patients on the CGI scales at end point.

The incidence of treatment-emergent adverse events was comparable between risperidone (84.3%) and placebo (83.9%). More patients discontinued due to adverse events in the risperidone-treated group (17.2%) than in the placebo group (11.2%). Differences in adverse event incidences between placebo and risperidone were observed for extrapyramidal symptoms (EPS), mild somnolence and the less common cerebrovascular adverse events (CAE). Risperidone induced neither orthostatic, nor anticholinergic side effects nor falls nor cognitive decline.

Of all atypical antipsychotics, risperidone has the largest database of double-blind controlled trials to support its efficacy and safety in the treatment of agitation, aggression, and psychosis associated with dementia. At the recommended doses, risperidone displayed a favorable risk-benefit profile. Risperidone was well tolerated with respect to EPS, somnolence, and anticholinergic side effects in this elderly population. In view of the risk for CAEs, risperidone, should be targeted towards the treatment of those patients in whom psychotic and behavioral symptoms of dementia are prominent and associated with significant distress, functional impairment or danger to the patient.     

Relationship between visual field loss and contrast threshold elevation in glaucoma

Background  

There is a considerable body of literature which indicates that contrast thresholds for the detection of sinusoidal grating patterns are abnormally high in glaucoma, though just how these elevations are related to the location of visual field loss remains unknown. Our aim, therefore, has been to determine the relationship between contrast threshold elevation and visual field loss in corresponding regions of the peripheral visual field in glaucoma patients.     

Laboratory study of HIV-1 and HTLV-I/II coinfection

A Retroviral Coinfection Clinic was established in 1991 at Charity Hospital Medical Center of Louisiana to study patients dually infected with human immunodeficiency virus (HIV) and human T lymphotropic virus (HTLV-I, HTLV-II). Eight patients were evaluated clinically, and by immunological and virological studies. Multiple neuromuscular diseases were observed, including tropical spastic paraparesis, polymyositis, and polyneuropathies. Only one patient developed AIDS. HIV-1 infected patients with HTLV-I, but not HTLV-II, coinfection have maintained stable CD4 counts, despite the fact that quantitative HIV DNA PCR suggests a relatively high copy number. HTLV-I/II antigens were detected in lymphocyte cultures from four patients, and lymphoblastoid cell lines have been established from two. These results support the contention that upregulated HTLV-I/II virus expression and disease manifestations occur during coinfection with HIV, sometimes in association with normal CD4 counts. © 1994 Wiley-Liss, Inc.