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Biomedical subjects

A Toledano

Publications and source records attributed to A Toledano.

At least 55 records · Page 3Linked to original sources
PubMed1994

Volatile anesthetics decrease peristalsis in the guinea pig ureter.

BACKGROUND: The origin of renal dysfunction associated with anesthesia and surgery is complex and incompletely understood. The effects of the volatile anesthetic agents isoflurane, enflurane, and halothane on the renal pacemaker and ureteral peristalsis may play an important role. METHODS: Guinea pig ureter and pelvis were dissected and placed in a sample chamber that allowed immersion in a temperature-controlled bath with gas (O2 with or without volatile agent) bubbled through the chamber continuously. The baseline frequency and amplitude of peristaltic contractions were measured on a polygraph recorder. The preparations were then exposed to up to 4 vol% volatile agent incrementally to generate a cumulative dose-response curve, and the subsequent frequency of peristaltic contractions was determined. The concentration of the volatile agent in solution was measured by gas chromatography. RESULTS: There was a significant dose-related decrease in the frequency of ureteral contractions for all three agents. A statistical model relating percentage baseline frequency to millimolar concentrations of volatile anesthetics showed that halothane produced a more pronounced decrease in frequency than did isoflurane or enflurane. However, the decrease was directly related to the MAC multiples and did not differ for the three agents. CONCLUSIONS: Ureteral peristaltic contractions are decreased in a dose-dependent manner by enflurane, halothane and isoflurane.

Animals↗
PubMed1992

Morphometric and neurosecretory changes in supraoptic neurons after D-amphetamine treatment.

Several morphological and immunochemical characteristics of the neurosecretory neurons of the supraoptic nucleus (SON) have been studied of rats treated for 1 month with D-amphetamine sulfate (AMP) (8 mg/kg weight, daily). An increase of SON volume (11%) has been observed as a consequence of the growth of the dorsoventral axis. Neurosecretory neurons increased their nucleolar area (11.4%), their nuclear area (8.3%), and their cytoplasmatic area (18.3%). Vasopressin immunoreaction did not show any differences between treated and control animals, but oxytocin immunostaining displayed an important increase (23.7%) in the neuronal cytoplasm of the treated rats. The SON hypertrophy of the AMP-treated rats corresponded to the hypertrophy/hyperfunction of its oxytocinergic neurons, and could be considered as a new mechanism of the action of the AMP. The results are discussed in relation to the plastic features of the SON and its central (neuronal) and peripheral (hormonal) function.

Animals↗
PubMed1992

Autoradiographic localization of receptors for glucagon-like peptide-1 (7-36) amide in rat brain.

Glucagon-like peptide-1 (GLP-1) has a sparse but well defined distribution in the rat brain where it is co-localized with glucagon-like immunoreactivity due to other fragments of the glucagon precursor. We have investigated the localization of GLP-1 receptors in rat brain using mono-125I-iodinated GLP-1(7-36) amide, the biologically active form of the peptide that occurs in brain, as the tracer for binding and autoradiographic studies of tissue sections. Displaceable binding of the label was sharply localized to discrete areas, being high in mamillary nuclei, the arcuate nucleus, nucleus of the solitary tract and the pretectal area, intermediate in the lateral septal nuclei, olfactory bulb, dorsal tegmental nuclei and the interpenduncular nucleus, and low in other regions. These results indicate areas where GLP-1(7-36) amide may have a role as a neurotransmitter or neuromodulator.

Animals↗
PubMed1990

Morphometric study on the development of magnocellular neurons of the supraoptic nucleus utilising immunohistochemical methods.

Vasopressin (VP)- and oxytocin (OXY)-producing neurons, components of the rat supraoptic nucleus, have been located with immunohistochemical methods, with the purpose of studying their morphofunctional characteristics during different phases of life (embryonic, juvenile, adult and senile). To carry out this study, an IBAS I (Kontron) computerised image analyser has been utilised. The hormone VP is first detected in the neuronal cytoplasm of 21 days old rat embryos and the hormone OXY appears in the neuronal cytoplasm later, in the newborn phase. The neuronal area with a positive reaction for the two neurohormones has been evaluated and it has been found that the quantity of reaction substance is proportional to the age. In the adult period, VP neurons possess a reaction area (198 microns 2) greater than that of OXY neurons (153 microns 2). In the SON, there are two neuronal shapes, fusiform and round; these shapes coexist in both hormonal types of neurons. Until Day 15 of postnatal development, the SON neurons are intermixed in the interior of the nucleus but in this period a neuronal redistribution is initiated. In the adult phase, OXY neurons are situated preferentially in the anterior, posterior and dorsal parts and VP neurons in the ventral and posterior parts, with both neurons being present in the intermediate part of the SON.

Aging↗
PubMed1985

Dysphagia and lower esophageal sphincter abnormalities after proximal gastric vagotomy.

We studied 96 patients subjected to elective proximal gastric vagotomy for intractable duodenal ulceration. Dysphagia was a frequent finding and occurred in 32 percent. It appeared in the immediate postoperative period and usually lasted for 1 to 2 months without any abnormalities in lower esophageal sphincter function. In five patients, dysphagia was severe and, although transient, was associated with changes in lower esophageal function simulating those observed in achalasia. The mechanism of these motor abnormalities is probably due to a reversible neuromuscular dysfunction of the lower esophageal sphincter.

Adult↗
PubMed1981

Study on distribution of polyanionic substances and glycoproteins in albino rats hippocampus during post-natal development.

The glycoproteins and polyanionic substances distribution on the albino rat hippocampus has been investigated during the post-natal development by using histochemical methods. It was observed that the Ruthenium Red and the Colloidal Iron disclose the existence of special neurons, the ones observed with Ruthenium Red being different from those shown with Colloidal Iron. The Ruthenium Red-positive neurons present a different distribution from that of the Colloidal Iron--positive ones, observing that the latter appear only in 30 to 35 days old rats. It may be that the Colloidal Iron-positive neurons are cells endowed with a great neurotransmissive activity.

Aging↗