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C Arias

Publications and source records attributed to C Arias.

At least 19 recordsLinked to original sources
PubMed1992

The melanin-concentrating hormone system of the rat brain: an immuno- and hybridization histochemical characterization.

In addition to a nonadecapeptide homologous to the teleost melanin-concentrating hormone (MCH), the amino acid sequence predicted from a rat prepro-MCH (ppMCH) cDNA suggested that at least one (neuropeptide EI, or NEI), and possibly a second (NGE), additional neuropeptide may be encoded by this precursor. Cross-reactivity with epitopes of NEI or NGE can account for reported localization of alpha-MSH, rat CRF, and human GRF in rat dorsolateral hypothalamic neurons. We have used antisera raised against rat MCH and NEI in immunohistochemical studies at the light and electron microscopic levels, along with hybridization histochemical localization of ppMCH mRNA, to define the organization of this system. As expected, ppMCH mRNA is prominently expressed in cells in the lateral hypothalamic area and zona incerta. The MCH and NEI peptides were extensively colocalized in neurons in both of these areas. In addition, smaller cell groups in the olfactory tubercle and pontine tegmentum were also positively hybridized for ppMCH mRNA and immunostained for MCH and NEI. Fibers stained for MCH and NEI were similarly, and very broadly, distributed throughout the central nervous system in patterns that generally conformed with known projection fields of the lateral hypothalamic area and zona incerta. A differential distribution was seen in at least one region, the interanterodorsal nucleus of the thalamus, which contained a prominent terminal field stained for MCH but not NEI. At the electron microscopic level, MCH-stained perikarya displayed a prominent staining associated with the Golgi apparatus; this was not encountered in NEI-stained cells. Both peptides were distributed similarly in terminals in the lateral hypothalamic area and median eminence, with staining associated principally with dense-cored vesicles. The results suggest that ppMCH-derived peptides may serve as neurotransmitters or modulators of prominence in a surprisingly expansive projection field of incerto-hypothalamic neurons. The terminal distributions of this system seem most compatible with functional roles in generalized arousal and sensorimotor integration, processes previously implicated as being subject to modulation by the lateral hypothalamic area.

Animals↗
PubMed1992

Inhibition of brain glutamate decarboxylase activity is related to febrile seizures in rat pups.

Because previous work showed that in the newborn brain, but not in the adult brain, glutamate decarboxylase (GAD) is notably susceptible to heat, we have studied the possible involvement of GAD inhibition in febrile convulsions and the related changes in gamma-aminobutyric acid (GABA) content. Rats of different ages were subjected to hyperthermia, and GAD activity was determined in brain homogenates by measuring the release of 14CO2 from labeled glutamate and by measuring the formation of GABA. The latter method gave considerably lower values than the former in the youngest rats, and was considered more reliable. With this method, we found a 37-48% inhibition of GAD activity in rat pups 2-5 days old, which showed febrile seizures at progressively higher body temperatures, whereas in 10- and 15-day-old animals, which did not show convulsions, GAD activity was not affected by hyperthermia. Whole-brain GABA levels, however, did not change at any age. In contrast to GAD, choline acetyltransferase and lactic dehydrogenase activities were not altered by hyperthermia at any of the ages studied. These results suggest that a decreased efficiency of the inhibitory neurotransmission mediated by GABA, consequent to the inhibition of GAD activity, may be a factor related to febrile convulsions.

Animals↗
PubMed1992

Effects of spaceflight on hypothalamic peptide systems controlling pituitary growth hormone dynamics.

Immunohistochemical and in situ hybridization localization of peptides derived from, and mRNAs encoding, prepro-somatostatin (ppSS) and prepro-growth hormone-releasing factor (ppGRF) was carried out on hypothalami from rats flown on biosatellites COSMOS 1887 and 2044 to investigate possible effects of reduced gravity on central hypophysiotropic systems controlling growth hormone (GH) secretion. Results from the COSMOS 1887 mission indicated that both SS and GRF immunostaining in the median eminence were diminished in flight animals relative to controls; no differences between groups in staining for other peptidergic neurosecretory systems were apparent. Animals flown on COSMOS 2044 displayed a more pronounced depletion of GRF than SS immunoreactivity from neurosecretory terminals in the median eminence. In addition, flight animals displayed significant 46-50% reductions in the number and signal intensity of presumed hypophysiotropic cells in the arcuate nucleus expressing ppGRF mRNA; positively hybridized cells in the region surrounding the ventromedial nucleus were less markedly affected. Both indexes of ppSS mRNA levels in the anterior periventricular nucleus were similar in flight and control rats. An additional group of animals that experienced hindlimb suspension, a manipulation that mimics the effects of weightlessness on several parameters, did not differ from controls in any of the above measures. These data suggest that exposure to microgravity results in a preferential reduction in GRF peptide and mRNA levels in hypophysiotropic neurons, which may contribute to impaired GH secretion described previously in animals subjected to spaceflight. Effects of weightlessness are not mimicked by hindlimb suspension in this system.

Animals↗
PubMed1992

[Use of standard protocols in the evaluation of voice disorders].

The purpose of this paper is to present a protocol for the use of standard forms in the evaluation of laryngeal structure and function in patients with voice disorders. The forms are designed to cover all the essential parameters needed to reach an accurate descriptive diagnosis which allows us to have an appropriate therapy plan according to the individual's detailed observations. It also gives us a consistent standardized evaluation form to measure changes after therapy whether behavioral, medical or surgical, and to compare different observations across patients. Reporting observations in this consistent manner will make characteristic patterns of different vocal behaviors readily obvious to the researcher or the clinician and reduce the possibility of missing any important details. The protocols are: indirect laryngoscopy, video-stroboscopic-evaluation form, functional voice and auditory perceptual voice evaluation.

Adult↗
PubMed1991

Somatotroph hypoplasia and dwarfism in transgenic mice expressing a non-phosphorylatable CREB mutant.

Most of the transcriptional effects of cyclic AMP are mediated by the cAMP response element binding protein (CREB). After activation of cAMP-dependent protein kinase A, the catalytic subunits of this enzyme apparently mediate the phosphorylation and activation of CREB. As cAMP serves as a mitogenic signal for anterior pituitary somatotrophic cells, we investigated whether CREB similarly regulates proliferation of these cells. We prepared transgenic mice expressing a transcriptionally inactive mutant of CREB (CREBM1), which cannot be phosphorylated, in cells of the anterior pituitary. If CREB activity is required for proliferation, the overexpressed mutant protein would effectively compete with wild-type CREB activity and thereby block the response to cAMP. As predicted, the CREBM1 transgenic mice exhibited a dwarf phenotype with atrophied pituitary glands markedly deficient in somatotroph but not other cell types. We conclude that transcriptional activation of CREB is necessary for the normal development of a highly restricted cell type, and that environmental cues, possibly provided by the hypothalamic growth hormone-releasing factor, are necessary for population of the pituitary by somatotrophic cells.

Amino Acid Sequence↗
PubMed1991

[Management of unilateral vocal cord paralysis].

The phoniatric analysis evaluates the importance of the vocal disorder and the appearance of the larynx what permets to find five clinical cases. For each one, there is a precise treatment: no treatment, rehabilitation with precises exercises in each case, collagen injection, early or secondary to rehabilitation. The rehabilitation will be intensive and done as soon as possible. It is based on a well known body proprioception. Intrinsic laryngeal muscles work, breathing exercises, exercises aimed at restoring the laryngeal sphincter will precede the pure vocal work. Author's experience shows that the results are good if rehabilitation is well indicated from the beginning and the patient with good motivations.

Humans↗
PubMed1991

Microalbuminuria in clinical practice.

Albumin excretion rate measured by new immunoassays and semiquantitative tests is advocated as a means for early detection of diabetic nephropathy. We determined albumin excretion rate in 276 patients. Albumin excretion rate was normal in 66%, within the microalbuminuric range in 27%, and within the macroproteinuric range in 7%. Significant predictors of albumin excretion rate included presence of hypertension and glycosylated hemoglobin level in type I diabetes mellitus, and years since diagnosis in type II diabetes mellitus. A semiquantitative test was deemed to be of limited diagnostic value. We conclude that testing for early diabetic nephropathy in routine clinical practice gives valuable information and that determination by a quantitative immunoassay based on a single 24-hour urine sample is preferable. The optimal frequency of screening and the levels that determine progressive renal disease have yet to be established.

Adult↗
PubMed1990

Inhibin beta, somatostatin, and enkephalin immunoreactivities coexist in caudal medullary neurons that project to the paraventricular nucleus of the hypothalamus.

Concurrent and sequential dual immunohistochemical labeling methods were used in combination, along with retrograde tracing techniques, to determine the extent to which inhibin beta (I beta), somatostatin-28 (SS-28), and enkephalin (ENK) immunoreactivity (IR) might be jointly expressed in neurons centered in the caudal part of the nucleus of the solitary tract (NTS) that project to the paraventricular nucleus of the hypothalamus (PVH). The results indicate that at least 65% of I beta-stained neurons in the NTS also express SS-28 IR, and at least 33% are ENK-positive. At least 25% of the I beta IR population stains positively for all three peptides. A substantial number of cells stained with markers for two, or all three, peptide families, could be retrogradely labeled following tracer deposits centered in the PVH. Prominent I beta and SS-28 IR projections from the caudal medulla to the hypothalamus have been described and include a preferential input to oxytocinergic (OT) compartments of the magnocellular neurosecretory system. The present results suggest that these arise in large measure from a common pool of neurons, a subset of which also shows ENK IR. Implications for the control of OT secretion, and for the processing of sensory information through the NTS, are discussed.

Animals↗
PubMed1990

Transmitter release in hippocampal slices from rats with limbic seizures produced by systemic administration of kainic acid.

The systemic injection of kainic acid (KA) has been shown to destroy neurons in the hippocampus and to induce limbic-type seizure activity. However, little is known on the neurochemical events that are associated with this convulsant effect. In the present work we studied the spontaneous and the K(+)-stimulated release of labeled tau-aminobutyric acid (GABA), glutamate, serotonin and dopamine, in hippocampal slices of KA-treated rats, at the moment of clinical seizures (2 h) and 72 h later. At the onset of convulsions we found a 40-45% decrease in the K(+)-stimulated release of GABA. The release of the other neurotransmitters was not significantly affected by KA treatment. After 72 h GABA release was still reduced by 30-40%. It is concluded that the epileptogenic effect of KA in the hippocampus is probably related to a diminished inhibitory GABAergic neurotransmission.

Animals↗
PubMed1989

Transgenic mice with inducible dwarfism.

The pituitary gland, composed of the anterior, intermediate and posterior lobe, represents a principal regulatory interface through which the central nervous system controls body physiology. The ontogeny of the growth hormone (GH) and prolactin (Prl) producing cells of the anterior pituitary has been analysed in transgenic mice, using the thymidine kinase obliteration system (TKO). Cells expressing the herpes virus 1 thymidine kinase (HSV1-TK) gene acquire pharmacological sensitivity to synthetic nucleosides such as FIAU (1-(2-deoxy-2-fluoro-beta-delta-arabinofuranosyl)-5-iodouracil), whose metabolites kill dividing cells. Consequently we created transgenic mice carrying the HSV1-TK gene under the control of either the rat growth hormone or the rat prolactin promoter. If transgenic mice expressing HSV1-TK in somatotropes (GH-producing cells) are treated with FIAU, they develop as dwarfs. The anterior pituitary in these animals is nearly devoid of both somatotropes and lactotropes (Prl-producing cells). By contrast, transgenic mice expressing HSV1-TK in the lactotropes, treated with FIAU, have anatomically and histologically normal pituitaries. Because toxicity depends on cell division, we conclude that Prl expression and lactotrope differentiation are post-mitotic events. These results indicate that both somatotropes and lactotropes derive from a common GH-expressing stem-somatotrope. Unexpectedly, the stemsomatotrope is still present in the adult animal and is capable of repopulating the pituitaries of treated animals with mature GH and Prl producing cells.

Animals↗
PubMed1989

[Treatment of tubal pregnancy by laparoscopy].

Three cases of ectopic pregnancy early diagnosticated are treated successfully with laparoscopic fulguration. Useful of this procedure is discussed and the needs of more experience is suggested.

Adult↗
PubMed1989

[Characteristics of the course of glottic cancer].

We present a retrospective study of the course of glottic cancer in a series of 302 cases. We studied the precise tumour localisation, the treatment carried out, the anatomico-pathological characteristics of the resected tissue and the results obtained as a function of the therapy used. It would seem important to stress the necessity of homogenizing the results of various authors by: presenting a series large enough for the results to be significant; there should be detailed total and prolonged follow up of patients, with use of similar evaluation parameters.

Glottis↗
PubMed1988

[Tinnitus].

Explore the source record for details and available documents.

Humans↗
PubMed1986

Differential calcium dependence of gamma-aminobutyric acid and acetylcholine release in mouse brain synaptosomes.

The dependence of gamma-aminobutyric acid (GABA) and acetylcholine (ACh) release on Ca2+ was comparatively studied in synaptosomes from mouse brain, by correlating the influx of 45Ca2+ with the release of the transmitters. It was observed that exposure of synaptosomes to a Na+-free medium notably increases Ca2+ entry, and this condition was used, in addition to K+ depolarization and the Ca2+ ionophore A23187, to stimulate the influx of Ca2+ and the release of labeled GABA and ACh. The effect of ruthenium red (RuR) on these parameters was also investigated. Of the three experimental conditions used, the absence of Na+ in the medium proved to be the most efficient in increasing Ca2+ entry. RuR inhibited by 60-70% the influx of Ca2+ stimulated by K+ depolarization but did not affect its basal influx or its influx stimulated by the absence of Na+ or by A23187. The release of ACh was stimulated by K+ depolarization, absence of Na+ in the medium, and A23187 in a strictly Ca2+-dependent manner, whereas the release of GABA was only partially dependent on the presence of Ca2+ in the medium. The extent of stimulation of ACh release was related to the extent of Ca2+ entry, whereas no such correlation was observed for GABA. In the presence of Na+, RuR did not affect the release of the transmitters induced by A23187. In the absence of Na+, paradoxically RuR notably enhanced the release of both ACh and GABA induced by A23187, in a Ca2+-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗