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Biomedical subjects

P Loo

Publications and source records attributed to P Loo.

14 recordsLinked to original sources
PubMed1992

Treatment of vaginal candidosis: a comparative study of the efficacy and acceptability of itraconazole and clotrimazole.

OBJECTIVE: To compare the clinical and mycological efficacy and patient acceptability of the oral antifungal itraconazole with vaginal clotrimazole in the treatment of vaginal candidosis. DESIGN: A multicentre, single-blind, randomised, parallel group comparison of itraconazole and clotrimazole. SETTING: 17 Genito Urinary Medicine clinics in UK hospitals. SUBJECTS: Women with symptomatic, culture positive vaginal candidosis. METHODS: Patients were randomly allocated 2 x 100 mg itraconazole capsules to be taken twice in a 24 hour period, or a 500 mg clotrimazole vaginal tablet. Clinical and mycological assessments were made at entry and after approximately seven and 35 days. OUTCOME MEASURES: Cure rate was defined in terms of mycological results, and patients were questioned on their opinion of treatment. RESULTS: Of 214 patients, 109 received itraconazole and 105 clotrimazole with similar improvement in clinical signs and symptoms. Mycological cure rates one week after treatment were obtained in 72 of 97 patients (74%) in the itraconazole group and 64 of 89 patients (72%) in the clotrimazole group. Identical mycological cure rates six weeks after treatment were obtained with 40 of 79 patients (51%) receiving itraconazole and 39 of 78 patients (50%) receiving clotrimazole. CONCLUSION: Clotrimazole and itraconazole were found to be equally effective. A majority of patients receiving the latter preferred it to previous treatments.

Adult↗
PubMed1987

Benzodiazepine receptor modulation of [35S]TBPS binding to the chloride channel. Noncompetitive inhibition of classical benzodiazepines and competitive inhibition of the partial agonist, CGS 9895, by CGS 8216.

Benzodiazepine receptor ligands are known to modulate the binding of [35S]TBPS to the chloride channel via an allosteric action. In the cases of diazepam, zopiclone and CGS 9895, the enhanced binding of [35S]TBPS induced by these benzodiazepine agonists was antagonized by CGS 8216. This antagonism was characterized both by a shift to the right and a decrease in the maximal stimulation, for the dose-response curves of diazepam and zopiclone. In the case of CGS 9895, the maximal response was not decreased. These data indicate that CGS 8216 is a noncompetitive antagonist of classical benzodiazepine receptor agonists but is a competitive inhibitor of the partial agonist, CGS 9895.

Animals↗
PubMed1987

Muscarinic, benzodiazepine, GABA, chloride channel and other binding sites in frontal cortex in hepatic coma in man.

Alterations in several neurotransmitter systems in brain have been implicated in the pathophysiology of hepatic coma (HC). Studies on human autopsy material are few. We investigated 3H-quinuclidinylbenzilate (QNB), 3H-spiperone, 3H-imipramine, 3H-PN-200-110, 3naloxone, 3H-flunitrazepam, 3H-muscimol, 35S-t-butylbicyclophosphothionate and 3H-cyclohexyladenosine binding sites in frontal cortex from seven patients with HC and five controls. The density of 3H-QNB binding sites was significantly decreased and the affinity slightly increased in HC. The functional significance of these selective changes in muscarinic receptor binding sites is unclear. Further studies evaluating cholinergic function in HC are indicated. Acute studies in animals point to an increase in GABA and BZ binding sites in HC. The present results show that the BZ/GABA-receptor-chloride-ionophore complex is unchanged in HC in man. Serotonergic (5HT-2), adenosine (A-1), imipramine (5HT uptake sites), opiate (naloxone) and calcium channel antagonist binding sites are unchanged in HC.

Adenosine↗
PubMed1986

Dose pipecolic acid interact with the central GABA-ergic system?

Several previous studies have suggested a strong GABA-mimetic action of the endogenous brain imino acid, L-pipecolic acid (L-PA). In the present study, these observations were evaluated using electrophysiological and neurochemical methods. In contrast to published data our electrophysiological studies on rat cortical neurones in situ showed only a weak, but bicuculline-sensitive depressant action of L-PA on cortical neurones. Furthermore, L-PA proved to have no affinity for any of the three components of the GABA-benzodiazepine-chloride channel receptor complex. However, using a modification of published methods a weak affinity for the GABA-B receptor site was demonstrated (IC50 = 1.8 X 10(-3) M). L-PA showed no anticonvulsive activity in several tests; in particular, it did not protect mice from seizures induced by inhibition of L-glutamate-1-decarboxylase (EC 4.1.1.15: GAD). L-PA had a very weak action on brain GABA levels of mice, and did not modify the rate of GABA synthesis. In conclusion, these results are not compatible with a strong in vivo interaction between L-PA and GABA-mediated inhibitory transmission.

Animals↗
PubMed1984

In vitro characterization of agonist, antagonist, inverse agonist and agonist/antagonist benzodiazepines.

The efficacy of coupling between the benzodiazepine receptor and chloride channel as well as the coupling to the GABA receptor is differentially affected by different benzodiazepine ligands. In general, the order of efficacy with regard to allosteric effects of benzodiazepine ligands on the chloride channel ([35S]TBPS) and GABA receptor ([3H]muscimol), is: agonist greater than agonist/antagonist greater than partial agonist greater than antagonist; with inverse agonists acting in a manner opposite to the classical benzodiazepine agonists. The chloride ionophore is allosterically modulated both by benzodiazepine and GABA receptors.

Animals↗
PubMed1984

In vitro characterization of benzodiazepine receptor agonists, antagonists, inverse agonists and agonist/antagonists.

Using an extensively washed membrane preparation and standardized incubation conditions, the actions of benzodiazepine (BZ) receptor ligands were evaluated on [3H]flunitrazepam [+/- 10 microM gamma-aminobutyric acid (GABA)], [3H]muscimol (+/- 2.5 microM etazolate) and [35S]butyl bicyclophosphorothionate (TBPS) binding. Classical BZ receptor agonists stimulated [35S]TBPS binding and [3H]muscimol binding in the presence of etazolate. These agents also possessed ratios for [3H]flunitrazepam binding in the absence and presence of GABA (GABA ratio) of 2 to 5. BZ antagonists and inverse agonists had GABA ratios less than 1 and did not alter, or reduced, both [35S]TBPS and [3H]muscimol (+etazolate) binding. The nonsedating BZ agonist/antagonist agents CGS 9896, CL 218872, PK 8165 and PK 9084 all possessed GABA ratios between 1.1 and 1.4 and only stimulated [35S]TBPS and [3H]muscimol (+etazolate) binding to approximately 50% of the level of classical BZ agonists. The BZ partial agonists CGS 9895 and RU 39419 both were unique in that they possessed GABA ratios of 1 or less, stimulated [35S]TBPS binding and had no effect on [3H]muscimol binding (+etazolate). Therefore, by monitoring the major components of the BZ receptor complex (BZ receptor, GABA receptor and chloride channel), we were able to distinguish between different BZ drugs and to support suggestions that these drugs act via unique BZ receptor populations which possess differential couplings to the GABA receptor and chloride channel.

Animals↗
PubMed1971

[The sleep cure].

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

Enhancement of the in vivo binding of [3H]flunitrazepam by the atypical neuroleptic, clozapine.

Modulation of the benzodiazepine receptor/GABA receptor/chloride ionophore complex in vivo involves a number of intricate regulatory interactions between the three components of the receptor complex. One way to assess these potential interactions involves the in vivo labelling of the benzodiazepine receptor with [3H]flunitrazepam. In these studies, we used this approach to demonstrate that the neuroleptic, clozapine, increases [3H]flunitrazepam binding in mouse brain in a bicuculline-reversible manner. This potentiation of benzodiazepine binding was not antagonized by picrotoxin and was found to result from a slower dissociation of [3H]flunitrazepam from the benzodiazepine receptor. These data suggest that clozapine acts to increase [3H]flunitrazepam binding via a GABAergic mechanism, independent of the chloride channel.

Animals↗
PubMedDate not supplied

Treatment of Neisseria gonorrhoeae infections in men with single-dose thiamphenicol.

A group of 50 men with uncomplicated gonococcal infections were treated with single, oral doses of 2.5 g of thiamphenicol. Reexamination, which included culture for Neisseria gonorrhoeae, was performed three to four days and seven days after treatment. Thirty-two (91%) of 35 men with urethral infections, 13 (87%) of 15 with rectal infections, and four (57%) of seven with pharyngeal infections were cured. None of the men from whom N. gonorrhoeae was reisolated admitted further sexual exposure. Treatment failure did not correlate with decreased sensitivity of the isolates to thiamphenicol in vitro. Three men had urethral infections with Chlamydia trachomatis before therapy, and the organism was reisolated after therapy in every case. No hematologic abnormalities occurred in any of the 50 patients treated with thiamphenicol, but 13 (26%) developed adverse gastrointestinal symptoms.

Administration, Oral↗