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Biomedical subjects

C Muñoz

Publications and source records attributed to C Muñoz.

At least 199 records · Page 11Linked to original sources
PubMed1981

Spatial discrimination, reversal and active or passive avoidance learning in rats with KA-induced neuronal depletions in dorsal hippocampus.

The neurotoxin kainic acid (KA) was iontophoretically administered to the dorsal hippocampus of female rats. Depending upon the diameter of the micropipette used to administered KA, this treatment completely depleted the dorsal hippocampus of nerve cell bodies (group LHC, N = 8) or selectively depleted CA4 (group SHC, N = 7) while sparing significant numbers of cells in CA1-CA3, and the fascia dentata. In both experimental groups, there was no apparent damage to the fimbria/fornix system, the ventral hippocampus and subiculum or neocortex adjacent to the injection site. The extensive neuron depletion (group LHC) sharply impaired the acquisition of a CAR in a shuttle box, produced a passive avoidance deficit in a step-through situation (but not in a punished-licking test), facilitated acquisition of a brightness discrimination in a T-maze, but had no significant effect on reversal learning in this situation. The more limited neuron depletions produced in group SHC produced no effect on CAR acquisition in the shuttle box but resulted in similar, though typically smaller effects in all other situations. The pronounced differences between this pattern of behavior change and that consistently reported after traditional lesions of the dorsal hippocampus indicate that damage to fibers of passage may contribute significantly to the classic hippocampal lesion syndrome.

Animals↗
PubMed1980

The outflow pathway in congenital glaucoma.

We obtained specimens from the angle of the eye during a trabeculotomy-trabeculectomy operation of a 5-month-old boy with congenital glaucoma. Light and electron miscroscopy of the anterior chamber angle showed the presence of mesodermal tissue covering the entire trabecular area. The trabecular meshwork showed thickening of trabecular beams, and an increased amount of collagen fibrils in the trabecular matrix. Internal trabecular spaces contained red blood cells; outer trabecular spaces were not apparent. The juxtacanalicular trabecular meshwork was thicker than in normal cases, because of an increased amount of collagen fibrils. The endothelium of Schlemm's canal was underlined by a thick and constant layer of amorphous material. These observations suggested that the site of increased resistance to aqueous humor outflow in congenital glaucoma could be found in abnormalities of the trabecular meshwork and the internal wall of Schlemm's canal.

Anterior Chamber↗
PubMed1980

Antagonistic effects of propranolol upon ethanol-induced narcosis in mice.

The interaction of dl-propranolol with narcosis induced by ethanol was studied in mice. dl-propranolol reduced significantly the duration of ethanol-induced narcosis. This antagonism was also present in animals pre-treated with pyrazole. The d-isomer of propranolol, devoid of beta-blocking action, did not decrease the duration of ethanol-induced narcosis. The blood levels of ethanol at the end of narcosis were similar in animals with or without dl-propranolol pre-treatment. These results support the hypothesis that this action of dl-propranolol could be mediated by central adrenergic beta receptors.

Animals↗
PubMed1979

Melanotic spinothoracic schwannoma.

A dumb-bell mediastinal melanotic schwannoma is described, and the rarity of this type of tumour emphasised. The tumour was resected by simultaneous laminectomy and posterior thoracotomy. The patient is well four years after operation. The pathology of the tumour is described and the origin of melanotic cells is discussed.

Female↗
PubMed1977

Subcellular distribution of rat brain cortex high-affinity, sodium-dependent, glycine transport sites.

The subcellular distribution of the membrane components, present in rat brain cortex homogenates, that interact with glycine in the presence of sodium ions was studied. The distribution in the primary fractions, as per cent of total binding in the homogenate, was: P1 ('nuclear'), 58%; P2 (large granule), 39%; P3 (microsomal), 2%9 Of the subfractions obtained by centrifuging P1 in a linear 0.32--1.5 M sucrose gradient, only the lighter fraction (P1-III) formed by large myelin fragments was enriched in specific binding activity with respect to P1. The pellet formed by purified nuclei had negligible binding, and fractions of intermediate density had a lower activity than P1. Transient exposure of P1-III to 1.5 M sucrose did not diminish its binding ability. Similarly, in the subfractions obtained by centrifuging P1 in a discontinuous sucrose gradient, only the least dense one, P1-A, that is formed exclusively by large myelin fragments, was enriched with respect to P1. The electron microscopy of these fractions is presented. The P2 subfractions, obtained in a linear 2--18% Ficoll gradient, had the following sodium-dependent activity (counts/min/mg protein, fractions being in the order of decreasing density): pellet, 0; P2-I, O; P2-II, 450; P2-III, 1770; P2-IV, 4130; unfractionated P2, 880; P2-IV, the least dense fraction being composed mainly of myelin. With P2 subfractions obtained in a discontinuous sucrose gradient (0.32, 0.8 and 1.2 M sucrose layers), it was also found that sodium-dependent glycine binding was only enriched, with respect to P2, in the myelin fraction P2-A. Glycine binding to purified brain cortex myelin was also found to be very high, while binding to non-myelin membranes, obtained during the purification procedure, was only 0--7% of that seen with myelin. These results suggest that high-affinity glycine binding is located in myelin proper, and possibly also in some other glial plasma membranes, but not in nuclei, mitochondria, endoplasmic reticulum or synaptosomes. The relevance of these findings for interpreting previous reports on high-affinity glycine transport in the central nervous system is analyzed.

Animals↗
PubMed1975

Quantitative electroencephalographic studies of the effects of ethanol in rabbits= I. Interaction between ethanol and reserpine.

At a dose of 1 g/kg i.v. ethanol induced in the cortical EEG of rabbits a synchronization which lasted 2-3 hours. Thereafter a pronounced hyper-stimulation occurred which persisted up to 4 hours. Pre-treatment of the animals with reserpine reduced markedly the initial synchronization and abolished the delayed stimulant effect. These findings are discussed in terms of possible interaction between acetaldehyde and biogenic amines.

Animals↗
PubMed1969

[Alveolar carcinoma].

Explore the source record for details and available documents.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMedDate not supplied

Effect of systemic pH, PCO2 and bicarbonate concentration on biliary bicarbonate secretion in the rat.

The effect of acute metabolic or respiratory acid-base disturbances on biliary bicarbonate secretion was examined in bile fistula rats. Animals were infused with ursodeoxycholate at a rate that stimulates bicarbonate secretion (1 mumole . min-1 X 100 gm-1), in control conditions and during acute acid-base disturbances. Metabolic acidosis or alkalosis were induced by HCl or NaHCO3 infusions, and respiratory acidosis or alkalosis were created respectively by adding CO2 to the inspired gas or by hyperventilation in artificially ventilated animals. Biliary bicarbonate concentration was always higher than plasma bicarbonate concentration. During metabolic disturbances, changing the plasma bicarbonate concentration from 9.2 to 30.2 mM stimulated biliary bicarbonate secretion by 113%. During respiratory disturbances, changing the plasma PCO2 from 25.5 to 59.8 mm Hg also increased biliary bicarbonate secretion by 89%. Biliary bicarbonate output was thus independent of plasma pH. When all animals were considered, bile flow was positively correlated with biliary bicarbonate concentration (r = 0.71, p less than 0.001). Acetazolamide significantly decreased ursodeoxycholate-induced bile flow and bicarbonate secretion by 20 and 22%, respectively. These results support the hypothesis that there is a relationship between ursodeoxycholate-induced bicarbonate secretion and bile flow. They are also consistent with the view that ursodeoxycholate-stimulated biliary bicarbonate secretion in the rat is strongly affected by plasma bicarbonate and PCO2, but not by plasma pH, and involves carbonic anhydrase.

Acetazolamide↗
PubMedDate not supplied

Isoenzymatic identification of Leishmania isolates from repeated clinical human leishmaniasis episodes in Catalonia (Spain).

Forty human strains of Leishmania infantum isolated in 1985-99 from 17 patients with repeated cutaneous, mucosal or visceral leishmaniasis episodes in Catalonia (Spain) were examined by isoenzyme electrophoresis. Six zymodemes were revealed: MON-1, MON-24, MON-28, MON-29, MON-33 and MON-34. In 2 patients 2 different zymodemes were identified in consecutive episodes.

Adult↗
PubMedDate not supplied

[Modifications of sympathetic tone induced by acupuncture reflex. Sympathetic electrical response and stimulus of 6PC].

INTRODUCTION: From certain experimental data obtained by experimental myocardial perfusion and clinical and animal studies, it would seem that this corroborates the finding that puncture of the acupuncture point (Neiguan, 6PC) has an effect on organic vegetative tone. OBJECTIVE: We aimed to establish, by means of a simple, conclusive, objective measuring system such as sympathetic electrical response, whether this point had this action and whether its effect was nonspecific or due to activation of a nervous tract subjacent to this point. PATIENTS AND METHODS: We assessed the sympathetic electrical response in 29 healthy volunteers in whom basal values were recorded and again after orthodox acupuncture stimulus in 6PC, and compared with data obtained of the effects caused by stimulus of an extra-acupunctural point, of a different acupunctural point of the same channel, of bipolar stimulation of the median nerve at the level of 6PC and with the modifications generated in the response by rest lying down during the period of the experiment. RESULTS: A significant increase was observed in the P1 latency of the sympathetic electrical response and significant reduction in its total amplitude, when 6PC was stimulated, an effect not observed in any of the other conditions of the experiment. CONCLUSION: We conclude that puncture stimulation of 6PC causes significant changes in sympathetic tone, which are not due to nonspecific effects of skin puncture, nor activation of the subjacent median nerve alone.

Acupuncture Therapy↗