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C Muñoz

Publications and source records attributed to C Muñoz.

At least 181 records · Page 10Linked to original sources
PubMed1987

Neuropathological changes in the rat brain cortex in vitro: effects of kainic acid and of ion substitutions.

The ionic mechanisms that may contribute to the neurotoxicity of kainic acid, were studied in a system of rat thin neocortical slices superfused in vitro. Slices superfused for 3 h under control conditions showed an essentially normal aspect when studied by light microscopy. Presence of 30 microM kainate in the superfusion fluid induced neuronal swelling, nuclear condensation and signs of necrosis in some cells, while other neurons, especially in deeper layers, appeared dark and condensed, with microvacuolation. The neuropil presented numerous profiles of swollen dendrites. When the slices were superfused with chloride-free medium, a large number of pyknotic neurons was seen. This was further enhanced by 30 microM kainate, which produced no swelling in this medium. These effects of Cl-free medium were almost entirely prevented in Cl-free medium without calcium and with 0.1 mM of EGTA. Sodium-free medium induced a marked neuronal swelling that was not much changed by kainate. When calcium in an otherwise normal superfusion fluid was reduced to 0.1 mM, a large number of pyknotic neurons, some with incrustations, were seen. Kainate (30 microM) in this low calcium medium led to a very large swelling and destruction of neurons, and to a spongy neuropil. These effects of kainate were greatly intensified in calcium-free-EGTA (0.1 mM) medium. Ca-free-EGTA medium by itself induced considerable neuronal and neuropil swelling. It is concluded that kainate induces neuronal swelling by a sodium- and chloride-dependent mechanism, and the enhancement of swelling in low calcium is due to an increased sodium uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Vitamin E deficiency in cystic fibrosis].

Plasma vitamin E levels were measured by high performance liquid chromatography in 42 children with cystic fibrosis and were correlated with the following parameters: sex, age, time of follow-up, clinical evolution (Schwachman score), vitamin E/cholesterol and faecal fat excretion. All children in this study received oral alfa-tocoferol (50-100 mg daily) from the diagnosis. According to the vitamin E level patients were distributed in two groups. Group I: 27 patients (64.3%) with normal concentrations. Group II: 15 patients (35.7%) with decreases plasma levels but without clinical manifestations. Steatorrhea was present in all children except 4 patients from group I and one patient from group II. On the other hand, vitamin E/cholesterol was normal in 80% of patients with vitamin E deficiency (group II). We did not find any correlation between plasma vitamin E levels and the different clinical and biological parameters studied. Further studies should be carried out to throw more light on the mechanism underlying the pathogenesis of vitamin E deficiency in patients with cystic fibrosis.

Adolescent↗
PubMed1986

New experimental criteria for optimization of solid-phase antigen concentration and stability in ELISA.

A peroxidase saturation technique for the determination of coating antigen concentration necessary to saturate polystyrene plates with a wide range of different antigens is described. The same technique has also been used to compare the stability of antigen-polystyrene bonds for native and denaturated antigens. Furthermore, the inappropriate selection of solid-phase antigen concentration and its influence on ELISA results is analyzed and an experimental criterion to select the optimum antigen concentration is proposed. Two different antigens, BSA-Ar and hydatid antigen, were used for ELISA determination of specific antibodies as a model system. Optimum solid-phase antigen concentration was determined by two different methods: peroxidase saturation, in which binding of peroxidase to non-antigen-occupied polystyrene surface sites was used to evaluate the degree of coating by antigen; chequer-board titration, using several immune sera of different affinity. Optimum antigen concentration selected by chequer-board titration using low affinity sera was similar to that selected with peroxidase saturation. On the other hand, lower antigen concentration would be selected by chequer-board titration using high affinity sera. For this reason, the concentrations of low affinity antibodies would be underestimated using the chequer-board titration. These results indicate that peroxidase saturation should be used to avoid avidity-dependent artifacts in ELISA.

Animals↗
PubMed1986

Glutamate in rat brain cortex synaptic vesicles: influence of the vesicle isolation procedure.

Rat brain cortex synaptic vesicles have been isolated by 3 different procedures. The one of Hata et al. (J. Neurochem., 27 (1976) 139) gave synaptic vesicles with a high glutamate content, but also, as judged by [3H]ouabain binding and electron microscopy, with considerable contamination by plasma membrane vesicles. This did not allow a precise estimation of the glutamate content of each synaptic vesicle. The second procedure used (Life Sci., 21 (1977) 1075), in which the tissue is homogenized with an all glass homogenizer, yielded vesicles of higher purity, but with no glutamate. A slightly modified Kadota and Kadota procedure (J. Cell Biol., 58 (1973) 135) gave synaptic vesicles of a very high purity that were filtered on a Sepharose 4B column, and there, the synaptic vesicle fraction of highest purity was estimated to contain 3640 glutamate molecules in each glutamatergic vesicle. This is equivalent to an intravesicular concentration of 0.21 M, that is, at least 10 times higher than the glutamate concentration in the rat brain cortex.

Animals↗
PubMed1986

Use of antidepressant drugs in the study of the role of biogenic amines in ethanol narcosis.

The interaction with ethanol of antidepressant drugs, imipramine (IMI), amitryptiline (AMI) and nomifensine (NOM), which differ in their activity on neuronal uptake of serotonin and catecholamines, was studied in the duration of narcosis in mice, normal and pretreated with p-chlorophenylalanine (PCPA) or alphamethyl-p-tyrosine (AMPT) and compared with similar experiments with pentobarbital. PCPA and AMPT pretreatment significantly reduced and prolonged respectively, ethanol narcosis but did not modify the effect of pentobarbital. IMI and less markedly AMI increased ethanol narcosis and antagonized the effect of PCPA. contrarily, NOM decreased the duration of ethanol narcosis, potentiated PCPA and antagonized the influence of AMPT. None of these antidepressants did modify pentobarbital narcosis. The alcohol blood level at awakening revealed that no important changes in ethanol metabolism are produced in the different experimental conditions. These results reinforce the hypothesis that serotonin favours the narcotic effect of ethanol, while noradrenaline reduces it. The influence of dopamine needs further studies.

Amitriptyline↗
PubMed1985

Evidence for a role of the preoptic area in lateral hypothalamic self-stimulation.

We examined the effects of unilateral radiofrequency lesions in the preoptic area on lateral hypothalamic self-stimulation in 15 rats. The animals were tested for self-stimulation in the lateral hypothalamus at 3 different current intensities from electrodes placed in both hemispheres, and then received a unilateral lesion in the preoptic area. Four hours later they were again tested for self-stimulation at the 3 current intensities and then daily over the following 14 days, or until they recovered their presurgical rates of self-stimulation. Rate of self-stimulation decreased in the damaged hemisphere, and recovered to prelesion levels within 2 weeks in 6 of 9 rats. In the intact hemisphere rate of self-stimulation increased above the prelesion level during a period from 1 to 2 weeks after the lesion. These results suggest that the preoptic area is involved in lateral hypothalamic self-stimulation. The effects of D-amphetamine (1 mg/kg) and apomorphine (2 mg/kg) injections on turning behavior were also studied in an open field and in a rotometer. Apomorphine induced contraversive turning to the lesion side in the open field and D-amphetamine induced ipsiversive turning in the rotometer.

Animals↗
PubMed1985

Lateral hypothalamic self-stimulation persists in rats after destruction of lateral hypothalamic neurons by kainic acid or ibotenic acid.

Bilateral injections of 1 microgram/microliter of kainic or ibotenic acid into the lateral hypothalamus (LH) of rats destroyed most of the cells in the LH. This treatment did not prevent electrical self-stimulation from electrodes placed in the LH, indicating that intrinsic neurons of the LH alone are not crucial elements of the neural system that mediates reinforcing hypothalamic stimulation.

Animals↗
PubMed1985

Multiple hepatic adenomas after long-term therapy with testosterone enanthate. Review of the literature.

We report a case of multiple hepatic adenomas developed in a 32-year-old man with renal allograft after long-term therapy with testosterone enanthate. Histological assessment showed a benign hepatocellular adenoma, which has not regressed over a 6-month follow-up since androgen withdrawal. A review of primary hepatic tumors associated with androgenic-anabolic steroid therapy published in the English literature has been carried out, concentrating on the more relevant recent publications. No previous case of hepatic adenoma with possible relationship to the use of non-17-alpha alkylated compounds has been reported.

Adult↗
PubMed1983

Hemodynamic effects of dobutamine in patients with alcoholic cirrhosis.

The effects of dobutamine infusion on cardiac output, hepatic blood flow, and the gradient between wedged and free hepatic venous pressures were studied in 14 patients with alcoholic cirrhosis. Cardiac output rose from 5.8 +/- 1.2 l/min (mean +/- SD) to 7.1 +/- 1.5 l/min. Hepatic blood flow and the gradient between wedged and free hepatic venous pressures did not change significantly during the dobutamine infusion (1.360 +/- 0.510 l/min to 1.446 +/- 0.502 l/min and 17.7 +/- 4.9 mm Hg to 17.9 +/- 3.7 mm Hg). We conclude that in alcoholic cirrhotic patients, dobutamine increased cardiac output as a result of increased heart rate and that there were no significant changes in percentage of cardiac output distributed to the liver.

Catecholamines↗
PubMed1983

[Effect of melatonin on L-leucine aminopeptidase in the hypothalamus and cerebral cortex of the normal and ovariectomized rat].

The effect of melatonin (500 micrograms/kg weight s.c. for 15 consecutive days) on the L-leucine amino peptidase (LAP) activity of the hypothalamus and brain cortex is studied on castrated and nan castrated rats. There was a significant increase in the LAP activity of hypothalamus (p less than 0.001 v.s. saline group) in the non castrated group, however, no changes were observed in the brain cortex. In the ovariectomized group injected from the 15th to 30th after castration, a very big decrease was recorded in the LAP activity in both the hypothalamus and brain cortex which was not modified by melatonin. This data is studied in relationship to the antigonadotrophic effect of melatonin on the non castrated animals since the changes of this activity in the hypothalamus are inversely related to the gonadotrophin secretion, specially luteinizing hormone.

Animals↗
PubMed1982

SEM and X-ray microanalysis of human prostatic calculi.

Calculi removed from human prostates affected with nodular hyperplasia were analyzed with scanning electron microscopy and EDAX system. The general spectrum was made up of Na, Al, Mg, S, P, Ca and Zn. Two types of stone were identified morphostructurally and microanalytically: calculi type I of nodular surface with high peaks of S, and calculi type II polyfaceted with high peaks of P and Ca. Their formation from corpora amylacea and/or exogenous constituents is discussed. The superficial deposit of Zn suggests its incorporation from the prostatic liquid and does not seem to play an important role in the genesis.

Calculi↗