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Biomedical subjects

M Rubio

Publications and source records attributed to M Rubio.

At least 199 records · Page 11Linked to original sources
PubMed1985

Inhibition by naloxone of the rise in hypothalamic dopamine and serum prolactin induced by ethanol.

We investigated the effect of naloxone on the concentration of dopamine in the hypothalamus and on the concentration of prolactin in serum and anterior pituitary of male rats acutely treated with ethanol. Acute ethanol administration increased serum prolactin levels and hypothalamic dopamine concentration. Pituitary prolactin was not modified by this treatment. Naloxone administered 15 min before the animals were sacrificed decreased serum prolactin levels and hypothalamic dopamine concentration in ethanol-treated rats. These results suggest that ethanol increases prolactin secretion because it decreases the release of dopamine by the hypothalamus. Naloxone decreases prolactin release probably because it antagonizes the inhibitory action of opioids on dopaminergic neurons.

Animals↗
PubMed1985

Effect of benznidazole on the mixed function oxygenase system from rat liver microsomes.

Previous Benznidazole (Bz) administration to rats (30 mg/kg, i.p.) significantly prolongs their pentobarbital sleeping time. This prolonging effect of Bz administration correlates with the inhibitory action of Bz on the liver aminopyrine or ethylmorphine N-demethylase activities. Inhibition of these enzyme systems by Bz is non-competitive and would not be related to changes in liver microsomal cytochrome P-450 (P-450) content or in cytochrome c-reductase activity or to interactions of Bz with P-450 leading to spectral changes. Covalent interactions of Bz reactive metabolites with microsomal proteins or phospholipids might be involved instead.

Aminopyrine N-Demethylase↗
PubMed1984

Collaborative clinical assay of the biological potency of allergen skin-test extracts.

A multicentre collaborative clinical trial has been made at one centre in each of six countries to decide if the potency of allergen extracts can be determined satisfactorily by skin-prick tests in man. Although there was considerable variation in potency of antigen when determined in different patients, if a sufficiently large group (n = 54) of persons were tested, it was shown to be feasible to compare potencies of sequential batches of the same specificity, and also of antigens of different specificities. It was shown that batches of mite extract were weaker than that of a grass pollen, but it proved to be a simple matter to adjust the concentration to give the same biological potency.

Adolescent↗
PubMed1984

Stability of Lolium perenne extract.

The stability of Lolium perenne extract was studied during a year in different conditions of storage. The changes of allergen activity were measured periodically by both in vivo and in vitro techniques, and structural modifications were examined by polyacrylamide gel electrophoresis and isoelectric focusing. Lyophilised extracts did not show any change and frozen samples retained full activity, but there were slight alterations in the pattern of proteins during the storage period. The activity of refrigerated aqueous extracts (4-6 degrees C) decreased gradually with time, while glycerinated samples at the same temperatures did not lose any of their allergen potency. Room temperature and 40 degrees C were unsatisfactory for aqueous extracts, but less so for preparations that contained 50% glycerol. The presence of the preservative phenol had a significant negative effect on stability at all of the temperatures studied.

Allergens↗
PubMed1983

Effect of nomifensine on cortisol, prolactin and biogenic amines in neurotic depressed patients.

The effect of nomifensine on plasma levels of cortisol, prolactin, dopamine, noradrenaline, adrenaline and serotonin were studied in neurotic depressive patients. Cortisol levels were elevated in the morning and were significantly decreased by nomifensine treatment. Prolactin levels were within the normal range and nomifensine did not modify them. A significative increase in catecholamine plasma levels was observed at the 6th week of treatment in depressed patients (dopamine: 106%; noradrenaline: 14%; adrenaline: 10%) whose nomifensine plasma levels ranged between 84 and 105 ng/ml. No statistical differences were found between pre- and post-treatment serotonin concentration. Reduction of plasma cortisol and clinical improvement may be related to increased catecholamine levels.

Adult↗
PubMedDate not supplied

Bioequivalence of two pharmaceutical forms of diltiazem.

Diltiazem, a calcium-channel blocking agent, has been shown to be a potent coronary vasodilator used in the treatment of ischaemic heart disease. The present study was conducted to compare the bioavailability of regular 60 mg tablets administered every 6 h with sustained release capsules of 120 mg administered every 12 h. High-performance liquid chromatographic analysis was carried out for determination of diltiazem and one of its metabolites desacetyldiltiazem in six male patients. The relative bioavailability of this sustained-release pharmaceutical form did not show any significant difference with that of tablets.

Capsules↗
PubMedDate not supplied

Infrequent cellular coexistence of NADPH-diaphorase and calretinin in the neurosecretory nuclei and adjacent areas of the rat hypothalamus.

Colocalization of the calcium-binding protein calretinin and NADPH-diaphorase activity at the cellular level was studied in the magnocellular secretory nuclei of the rat hypothalamus using sequential immunocytochemical and histochemical staining of the same sections. A low degree of colocalization of these markers was observed in certain cellular subpopulations within all the areas considered (supra-optic, paraventricular, circular and both fornicals nuclei and in the hypothalamic area located between the supraoptic and paraventricular nuclei). However, since in the paraventricular nucleus both markers were expressed by different neuronal populations, the coexistence was almost non-existent in some subdivisions of this nucleus. This rare coexistence strongly suggests that NADPH-diaphorase and calretinin are related to different functions shared by restricted hypothalamic neuronal populations.

Animals↗
PubMedDate not supplied

Expression of the mu-opioid receptor in the anterior pituitary gland is influenced by age and sex.

To analyze whether opioids are able to modulate endocrine regulation by acting directly on rat pituitary cells, an immunohistochemical study of micro-opioid receptor expression in these cells was performed, with attention given to the analysis of potential age- and sex-related variations in receptor expression patterns. In both sexes, the micro-opioid receptor was detected in the pituitary pars distalis. However, significant age-related differences were observed. Both in male and female rats, the percentage of micro-opioid receptor-expressing cells decreased significantly from postnatal week one through the 24 months of our study. Interestingly, pituitary cells containing the micro-opioid receptor were significantly more numerous in male than in female, with exception of the pre-pubertal phase and old rats. According to two-way analysis of variance, the gender-related differences in micro-receptor expression were independent of age-related variations. Thus, without excluding hypothalamic actions, our results suggest that opioids may exert their endocrine function by acting directly on pituitary cells.

Age Factors↗
PubMedDate not supplied

Dietary recommendations for patients allergic to Anisakis simplex.

BACKGROUND: Anisakis simplex, a fish parasite, causes allergic urticaria, angioedema and anaphylactic shock through an IgE-mediated hypersensitivity mechanism. Consensus on the dietary recommendations that should be given to allergic patients is lacking. Our objective was to evaluate the usefulness of different types of diets in preventing further reactions in patients allergic to A. simplex. METHODS: Twenty-eight adult patients, who had suffered an allergic episode caused by A. simplex were asked to follow one of the following three diets for a mean period of 13.16 months: a fish-free diet (diet 1; n = 19), a diet including fish frozen for more than 48 hours (diet 2; n = 9) and a diet with fresh fish (diet 3; n = 12). In all patients raw fish was excluded. Relapse rates and changes in total serum IgE and specific IgE to A. simplex were studied during the follow up. RESULTS: During the 13-month follow-up none of the patients developed anaphylaxis. Urticaria symptoms were present in 5.8 %, 11.1 % (n.s) and 33.3 % (p = 0.016) of patients following diets 1, 2 and 3, respectively. Total IgE decreased by 64 % (p < 0.05), 48 % (p < 0.05) and 39.4 % (p < 0.05), respectively. Specific IgE to A. simplex decreased by 50.7 % (p < 0.05), 54.1 % (p < 0.05) and 23.6 % (p < 0.05) after diets 1, 2 and 3, respectively. No statistically significant differences were found among the groups in variations in total and specific IgE. CONCLUSIONS: Patients allergic to A. simplex can eat fish that has been frozen at -20 C for 48 hours without risk of a severe allergic reaction. Long term decreases in specific and total IgE may not be good markers of eventual contact with A. simplex.

Adult↗
PubMedDate not supplied

Astroglial induction of in vivo angiogenesis.

A purified population of astrocytes was prepared from embryonic rat hypothalamus. These cells were transplanted into the cerebral cortex of adult rats with survival time of 5 days and studied by glial fibrillary acidic protein (GFAP) immunohistochemistry and electron microscopy. A progressive gradation from the edges of the implant to the intact host tissue was observed in relation to the vascularization process. The regenerating tissue showed cells with cavities resembling capillary central lumens and their cytoplasms revealed gold particles when they were immunostained for electron microscopy. Dark processes were seen in capillary-like lumens and, on other occasions, evaginations of endothelial cells were in contact with astroglial processes. These findings lead us to suggest that capillary-like structures might develop from cavitated astroglial cells, which would permit the migration of endothelial cells into their lumens. Astroglial-endothelial interactions persist until endothelial cells are morphologically differentiated. One possible interpretation of the present data is that astrocytes might participate directly and actively in the regulation of capillary formation.

Animals↗