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Biomedical subjects

R Mata

Publications and source records attributed to R Mata.

53 records · Page 3Linked to original sources
PubMed1990

Efficacy of clonidine, guanfacine and methadone in the rapid detoxification of heroin addicts: a controlled clinical trial.

The efficacy of clonidine, methadone, and guanfacine in rapid detoxification of heroin inpatients was assessed in a randomized controlled clinical trial. Signs and symptoms of abstinence and of side effects were analysed in 90 heroin addicts successfully completing a 12-day inpatient trial. All patients fit DSM-III criteria for opioid dependence, the age range being 18 to 36 years. All three drugs were effective in controlling abstinence; however, the course of abstinence was different in the methadone group as compared to the adrenergic agonists, the latter showing limitations in their ability to suppress withdrawal manifestations. While mean number of withdrawal signs and symptoms was significantly lower during days 2 to 5 in the methadone group (p less than 0.01), adrenergic agonists were slightly more effective at the end of the trial. Incidence of side effects was closely related to the dose administered. Hypotensive action of adrenergic agonists was more marked in orthostatic position. The present results suggest that methadone is superior to adrenergic agonists. Between these drugs clonidine appears to be less effective than guanfacine in controlling some withdrawal manifestations, and causes more side effects, mainly of cardiovascular nature.

Adrenergic alpha-Agonists↗
PubMed1989

Success and failure at inpatient heroin detoxification.

Predictors of either detoxification success or failure were evaluated during an inpatient trial that compared the efficacy of methadone, clonidine and guanfacine for rapid heroin detoxification. The analysis of such predictors was stimulated by the fact that in order to achieve 90 patients who completed the study (30 in each group), a total of 170 patients had to be included. Of 80 detoxification failures, 10 occurred in the methadone group, 32 in the guanfacine group, and 38 in the clonidine group. Voluntary request for discontinuation of the detoxification schedule was the first cause of failure. There were not statistically significant differences with regard to sociodemographic characteristics and pattern of drug consumption among patients in the three groups who completed detoxification with success or failure. The treatment drug, the type of schedule and the score obtained from the Symptom Checklist-90/Revised (SCL-90/R) were the only predictors of either detoxification success or failure. Inpatient opioid detoxification would be a useful strategy for patients with more severe psychological symptoms.

Adult↗
PubMed1989

[Circadian variations in the production of superoxide and liberation of lysosomal enzymes of neutrophils in peripheral blood].

Superoxide formation and lysosomal enzyme liberation circulating neutrophils has been assessed in healthy subjects. Blood samples were obtained at 8:00, 14:00, and 20:00 o'clock. The formation of superoxide followed a circadian rythm. Lowest concentration was found a 14:00 hours (4.59 +/- 2.09 nM reduced cytochrome/10(6) neutrophils). No 24 hour variation of betaglucuronidase and lysozyme liberation was proven. The number of neutrophil receptors for formyl-methyonil-leucyl-phenyl-alamine (FMLP) at the same hours did not show any circadian variation. The circadian changes of the functional capacity of the neutrophils might be one of the mechanisms that could justify the 24 hour variation of symptomatology characteristic of some diseases.

Adult↗
PubMed1988

Comparison of the active calcium extrusion, calcium buffering capacity and ATPase activity in rabbit reticulocytes and mature red cells.

The purpose of the present work was to study the changes in the pattern of calcium homeostasis following the loss of intracellular organella during red cell maturation. Reticulocytes and mature red cells were prepared from anaemic rabbits blood after daily bleeding. Experimental protocols were designed to study the calcium buffering capacity in intact and digitonin-disrupted cells, the calcium pumping rate and, the Ca2+-translocating ATPase activity in the aforementioned red cells subpopulations. In digitonin-disrupted cells, a vesicular calcium pool, sharing the properties of mitochondria, could be detected in reticulocytes but no in mature red cells. Calcium content and calcium buffering capacity were significantly lower in reticulocytes than in mature red cells. The pattern of active calcium extrusion was quite similar in the two cell subpopulations, although reticulocytes had somewhat higher calcium affinity. Besides, an estimation of the calcium pumping rate gave higher values in reticulocytes than in mature erythrocytes. These values were 21 and 9 mmol/l cells per h, respectively. Maximal activities of the high-affinity (Ca2+ + Mg2+)-ATPase and basal Mg2+-ATPase were significantly higher in reticulocytes than in mature red cells, but no differences were observed regarding calcium affinity. The results show that changes in the properties of the Ca2+-translocating ATPase and intracellular calcium buffering systems are mechanisms involved in the process of red cell maturation.

Adenosine Triphosphatases↗
PubMed1988

[Effect of corticosteroids, quinacrine and L-652, 731 on experimental aggregation of polymorphonuclear leukocytes induced by complement and platelet activating factor (PAF)].

The effects of 6-methylprednisolone sodium succinate, quinacrine and the synthetic anti-PAF compound L-652,731 were studied on the PAF and complement induced aggregation of rabbit polymorphonuclear leukocytes in vivo. High doses (100-250 mg/kg) of corticosteroid were able to abrogate PAF and complement induced aggregation. Quinacrine (1.25 mg/kg), and L-652,731, partially precluded complement-depending aggregation. The L-652,731 dose employed was just enough to prevent PAF induced aggregation. These results suggest that in those pathological conditions in which polymorphonuclear aggregation occurs, factors other than those derived from plasmatic complement system activation, and laboring jointly with it, may be involved.

Agranulocytosis↗
PubMed1980

Cactus alkaloids XLII: 3,4-dimethoxy-beta-phenethylamine and heliamine from the Mexican cereoid Backebergia militaris.

Backebergia militaris (Andot) Bravo ex Sánchez Mejorada yielded alkaloid crystals from a fractionated ethanol extract of only 20 g of plant material. The alkaloid was identified as heliamine (6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline) hydrochloride. A second alkaloid, 3,4-dimethoxy-beta-phenethylamine hydrochloride, was crystallized after preparative TLC of the mother liquors. Both compounds were isolated previously from other cactus species.

Alkaloids↗
PubMedDate not supplied

Chemical studies on Mexican plants used in traditional medicine, III: New 4-phenylcoumarins from Exostema caribaeum.

Investigation of the MeOH extract of Exostema caribaeum (Rubiaceae) led to the isolation of three new 4-phenylcoumarins. Their structures, 5-O-beta-D-galactosyl-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin [1a] 7,4',5'-trihydroxy-4-phenyl-5,2'-oxidocoumarin [2a] and 7,4'-dimethoxy-5'-hydroxy-4-phenyl-5,2'-oxido-coumarin [3a] were elucidated by spectral methods and chemical transformations. It was also demonstrated that 4-phenylcoumarins undergo oxidative cyclization under basic conditions in the presence of air to give 4-phenyl-5,2'-oxido-coumarins.

Acetylation↗
PubMedDate not supplied

Chemical studies on mexican plants used in traditional medicine, VI. Additional new 4-phenylcoumarins from Exostema caribaeum.

Six additional 4-phenylcoumarins have been isolated from the MeOH extract of the bark of Exostema caribaeum. Their structures were determined by physical and chemical methods as 4'-5'-dihydroxy-7-methoxy-4-phenyl-5,2'-oxidocoumarin [1], 5,7,4'-trimethoxy-4-phenylcoumarin [2], 5,3'-dihydroxy-7,4'-dimethoxy-4-phenylcoumarin [3], 5-O-beta-D-galactopyranosyl-7,4'-dimethoxy-4-phenylcoumarin [6], 5-O-beta-D-glucopyranosyl-3',4'-dihydroxy-7-methoxy-4-phenylcoumarin+ ++ [7], and 5-O-(6"-acetyl)-beta-D-galactopyranosyl-3', 4'-dihydroxy-7-methoxy-4-phenylcoumarin [9]. The last four compounds are new natural products.

Anti-Infective Agents↗
PubMedDate not supplied

Chemical studies on Mexican plants used in traditional medicine, XV. Sesquiterpene evoninoate alkaloids from Hippocratea excelsa.

Three sesquiterpene evoninoate alkaloids, hippocrateine I [1], hippocrateine II [2], and emarginatine A have been isolated from the root and stem barks of Hippocratea excelsa. Compounds 1 and 2 are new naturally occurring substances. The structure of 1 was unequivocally established by X-ray crystallographic analysis, and the structure of the second new alkaloid was deduced by spectral analysis.

Alkaloids↗
PubMedDate not supplied

Phytotoxic and photosynthetic activities of maduramicin and maduramicin methyl ester.

The polyether antibiotic maduramicin and its methyl ester derivative inhibited photophosphorylation and proton uptake in isolated spinach chloroplasts. Both compounds also enhanced basal and phosphorylating electron transport and stimulated Mg(2+)-dependent ATPase activity, therefore, they behave as uncouplers of photophosphorylation being the methyl ester derivative more potent than the parent compound. On the other hand, maduramicin inhibited germination and radicle elongation of several crop and weed species. In addition, the antibiotic caused phytotoxic injury and fresh weight reduction to 4-to-6 week old seedlings of two weed and two crop species when applied at 10(-4) M by foliar application in the greenhouse.

Anti-Bacterial Agents↗