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Biomedical subjects

L M Torres

Publications and source records attributed to L M Torres.

At least 19 recordsLinked to original sources
PubMed1991

Pharmacokinetics and distribution of ketamine after extradural administration to dogs.

We have studied the pharmacokinetics and distribution of ketamine and its biotransformation products in dogs after extradural administration of ketamine at L4-5. The mean apparent uptake rate constants of ketamine for plasma and CSF were 4.17 (SD 1.84) and 5.15 (2.50) h-1, respectively. The concentrations of ketamine in CSF were greater than those found in plasma. The elimination half-life values of the parent drug for both biological fluids were similar (4.3 (2.96) h and 4.6 (3.31) h for plasma and CSF, respectively). The apparent formation rate constant of norketamine was greater than that of dehydronorketamine. However, the concentrations of the biotransformation products in CSF were smaller than those of the parent drug. These results are similar to the distribution of ketamine and its metabolites in different cerebral structures and tissues. The concentrations decreased in concert with the increase in polarity of the metabolites. A specific distribution for all compounds was observed. Ketamine showed a greater affinity for brainstem, while norketamine and dehydronorketamine were distributed mostly in cerebellum and kidney, respectively.

Anesthesia, Epidural↗
PubMed1991

Analgesic activity of a triterpene isolated from Scoparia dulcis L. (Vassourinha).

Analgesic and anti-inflammatory activities of water (WE) and ethanolic (EE) extracts of Scoparia dulcis L. were investigated in rats and mice, and compared to the effects induced by Glutinol, a triterpene isolated by purification of EE. Oral administration (p.o.) of either WE or EE (up to 2 g/kg) did not alter the normal spontaneous activity of mice and rats. The sleeping time induced by sodium pentobarbital (50 mg/kg, i.p.) was prolonged by 2 fold in mice pretreated with 0.5 g/kg EE, p.o. Neither extract altered the tail flick response of mice in immersion test, but previous administration of EE (0.5 g/kg, p.o.) reduced writhings induced by 0.8% acetic acid (0.1 ml/10 g, i.p.) in mice by 47%. EE (0.5 and 1 g/kg, p.o.) inhibited the paw edema induced by carrageenan in rats by respectively 46% and 58% after 2 h, being ineffective on the paw edema induced by dextran. No significant analgesic or anti-edema effects were detected in animals pretreated with WE (1 g/kg, p.o.). Administration of Glutinol (30 mg/kg, p.o.) reduced writhing induced by acetic acid in mice by 40% and the carrageenan induced paw edema in rats by 73%. The results indicate that the analgesic activity of S. dulcis L. may be explained by an anti-inflammatory activity probably related to the triterpene Glutinol.

Animals↗
PubMed1991

Cardiac glycosides isolated from the Indian-snuff, Maquira sclerophylla Ducke.

The hydroalcoholic extract of the powdered bark of the Indian-snuff Maquira sclerophylla Duck was purified by column chromatography in silica-gel and the major cardenolide isolated from preparative TLC was identified by 1H-NMR, 12C-NMR and IR analyses. The spectra showed that the active substance has strophanthidin as the aglycone.

Brazil↗
PubMedDate not supplied

[Diazepam reversion with flumazenil. Gasometric and sympathetic-adrenal study].

We report the effects of flumazenil as reversion agent of the effects of diazepam at high doses as a part of short-duration general anesthesia. We have studied ten women in ASA I general condition who received anesthesia with fentanyl, 2.5 micrograms/kg-1, diazepam, 0.4 mg/kg-1 and O2/N2 at 60%. At the end of the operation, flumazenil, 0.2 mg, was administered. Hemodynamic, respiratory and adrenergic effects were evaluated. The degree of awareness and subjective feeling of the patient at awakening were also evaluated. After administration of flumazenil, awareness state was significantly higher (p less than 0.001) and it persisted during the duration of the study (120 minutes). Respiratory rate and pO2 increased significantly with administration of flumazenil (p less than 0.25 and p less than 0.01, respectively) and pCO2 decreased from 42.2 mmHg to 37.9 mmHg (p less than 0.05). Neither hemodynamic parameters nor plasma concentration of catecholamines changed significantly. As secondary effects attributable to flumazenil, four patients complained of nausea and one patient referred anxiety. We conclude that flumazenil allows to carry out anesthetic techniques with high doses of benzodiazepines even in short duration interventions with safety and without cardiocirculatory nor sympathetic-adrenal alterations.

Adrenal Glands↗
PubMedDate not supplied

Detection and analysis of paraquat in confiscated marijuana samples.

A spectrophotometric method used to test for paraquat in 160 confiscated marijuana samples is described. Twenty of these samples (12.5 per cent) tested positive for paraquat. Nine confiscated hash oil samples tested negative. The identification of paraquat was proven by isolation, chromatography, and spectral methods. The cannabinoids in paraquat positive Cannabis samples were analysed.

Cannabis↗