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Biomedical subjects

R B Roy

Publications and source records attributed to R B Roy.

At least 19 recordsLinked to original sources
PubMed1996

AIDS and the eyes.

Explore the source record for details and available documents.

AIDS-Related Opportunistic Infections↗
PubMed1996

Comparison of the efficacy and safety of oral fluconazole and topical clotrimazole in patients with candida balanitis.

One hundred fifty seven men with candidal balanitis were entered in a randomised, open-label parallel-group multicentre study comparing efficacy and safety of a single oral 150-mg fluconazole-dose with clotrimazole applied topically twice daily for 7 days. Of 64 fluconazole and 68 clotrimazole treated patients who were evaluable at short term follow up, 92% and 91% respectively were clinically cured or improved. Candida albicans was eradicated in 78% and 83% of patients respectively. Median time to relief of erythema was 6 days for fluconazole and 7 days for clotrimazole. Twelve of 15 patients who had received previous topical therapy for balanitis said they preferred oral therapy. At the one month follow up visit, 24/36 and 29/33 patients in the two groups were clinically cured or improved. Nine in the fluconazole group experienced a relapse; 6 of these 9 patients reported previous episodes of this infection during the past year. Two patients in the clotrimazole group had a relapse; neither had a history of previous episodes. Mycological eradication was noted in 26/36 and 25/33 patients in the two groups. Both treatment regimens were well tolerated. Thus a single 150 mg dose of fluconazole was comparable in efficacy and safety to clotrimazole cream applied topically for 7 days when administered to patients with balanitis.

Administration, Oral↗
PubMed1992

Simulation modelling for HIV infection and AIDS.

In this paper we describe a computer model developed jointly by mathematicians and medical consultants. The aim of the model is to provide practical help to people involved with caring for HIV-infected patients. The program is easy to use and can provide a wide variety of output, ranging from resource requirements and costs to detailed clinical information. The model uses the technique of computer simulation to study the progression of HIV-related diseases in a set of patients. The model can help planners concerned with the broad issues of health care provision, as well as clinical users whose main interest is the management and treatment of individual patients. The model is currently being tested in the Department of Genito-Urinary Medicine in the Royal Victoria Hospital, Bournemouth. The potential capability of the model is illustrated by some results from program runs using data from a set of Bournemouth patients. We argue that the power and flexibility of computer simulation as a technique for dealing with uncertainty and variability is especially appropriate in the case of HIV and AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Platelet activating factor antagonists interact with GABAA receptors.

Platelet activating factor (PAF) is ubiquitous in mammals, and may have multiple functions in the central nervous system. Triazolobenzodiazepine compounds are active both at the GABAA receptor and as PAF antagonists. To investigate whether PAF antagonist activity is involved in the actions of triazolobenzodiazepines, we examined effects of two non-benzodiazepine PAF antagonists on binding and function at the GABAA receptor. The gingkolide terpene, BN 52021 and the dioxolane-based compound BN 52115 had no effect on benzodiazepine binding or chloride channel binding in cortical membrane preparations. However, chloride uptake into cortical synaptoneurosomes was enhanced with 1 microM BN 52021 but not 1 microM BN 52115. The effect of BN 52021 was prevented by 1 microM flumazenil. PAF antagonists appear to augment GABAA receptor function without affecting binding.

Animals↗
PubMed1989

Chronic benzodiazepine administration. IV. Rapid development of tolerance and receptor downregulation associated with alprazolam administration.

The triazolobenzodiazepine compound alprazolam may have unique clinical effects compared to other benzodiazepines, and both behavioral and neurochemical studies have indicated unusual results after acute doses of alprazolam. To determine the effects of chronic dosage in mice, alprazolam (2 mg/kg/day) was administered via osmotic pumps for 1-14 days, and open-field activity, plasma and brain concentrations, benzodiazepine receptor binding in vivo and in vitro, [35S]t-butylbicyclophosphorothionate ([35S]TBPS) binding, and muscimol-stimulated chloride uptake were determined. Alprazolam decreased motor activity after 1 and 2 days, but tolerance developed by day 4 and persisted to day 14. Plasma and brain concentrations remained constant during the 2-week period. Benzodiazepine receptor binding in vivo was decreased at day 4 compared to day 1 in cortex (CX) and hypothalamus (HYPO), and remained depressed to day 14 in CX but not HYPO. Benzodiazepine binding in vitro and [35S]TBPS binding were decreased in CX at day 7. Muscimol-stimulated [36Cl-] uptake was decreased at days 4 and 7 compared to day 1, but at day 14 uptake was similar to day 1. These results indicate that behavioral tolerance and receptor downregulation develop rapidly during chronic alprazolam administration. Behavioral and neurochemical changes were similar to those associated with lorazepam administration, but occurred more rapidly and with different regional specificity.

Alprazolam↗
PubMed1989

Persistent alterations in GABAA receptor binding and function after prenatal lorazepam administration in the chick.

Behavioral abnormalities have been reported in young and adult animals exposed to benzodiazepines prenatally. The presence of neurochemical alterations in the GABAergic system after prenatal benzodiazepine exposure was assessed in a chick model which avoids prenatal and postnatal maternal effects. The GABAA receptor complex, the presumed site of benzodiazepine action, was altered in adult chickens previously exposed to lorazepam for 10 days in ovo. Binding was decreased at the putative chloride channel site labeled by [35S]TBPS, coupling was decreased between this site and the GABA binding site, and function of the GABAA receptor in chloride uptake was diminished in animals exposed to prenatal lorazepam. Persistent neurochemical alterations in the GABAergic system accompany prenatal benzodiazepine exposure, and may influence subsequent behavior and development.

Animals↗
PubMed1989

MIF-1 and Tyr-MIF-1 augment muscimol-stimulated chloride uptake in cerebral cortex.

The peptides MIF-1 (Pro-Leu-Gly-NH2) and Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) recently have been found to augment the effects of gamma-aminobutyric acid (GABA) on benzodiazepine receptor binding and chloride channel binding (Tyr-MIF-1) at the GABAA receptor complex. To determine whether these peptides affect the function of this complex in chloride transport, we evaluated chloride uptake stimulated by the GABA analog muscimol in synaptoneurosome preparations. In mice treated with either MIF-1 or Tyr-MIF-1 (1 mg/kg IP), maximal chloride uptake in cortex was increased compared with controls. The two peptides had similar effects in cortical preparations, but in cerebellum neither peptide altered chloride uptake. No differences from controls were observed in cortical synaptoneurosomes treated in vitro with either MIF-1 or Tyr-MIF-1. These results suggest that the brain peptides MIF-1 and Tyr-MIF-1 alter function at the GABAA receptor complex, perhaps by binding at a specific peptide receptor.

Animals↗