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Biomedical subjects

A Toledano

Publications and source records attributed to A Toledano.

At least 37 records · Page 2Linked to original sources
PubMed1996

Distribution of glyoxylate dehydrogenase activity in cortical and subcortical regions of the rat brain. A light microscopic histoenzymological study.

The distribution of the glyoxylate dehydrogenase (GLYO-DH) (Glyoxylate oxidoreductase) activity has been investigated in rat brain using the corresponding histochemical method. The results have demonstrated a positive histochemical reaction in neurons of several cortical and subcortical areas. These neurons are located in the same regions in which operate monoaminergic neurotransmitters. These facts suggest a possible interaction between glyoxylic acid and monoaminergic neurotransmission.

Aldehyde Oxidoreductases↗
PubMed1996

Radiation can inhibit tumor growth indirectly while depleting circulating leukocytes.

The growth of certain UV-radiation-induced tumors is suppressed by T lymphocytes, but it has been proposed that non-T lymphocytes stimulate the growth of several of these tumors. In this study, the indirect effects of X irradiation on the growth of one such tumor in T-cell-deficient nude mice was tested. Even when the site of tumor cell injection was shielded, whole-body irradiation with 6 Gy before tumor challenge inhibited subsequent tumor growth significantly. The interval during which this indirect inhibition was observed correlated with the depletion of circulating leukocytes, which did not return to normal levels until 12-21 days after irradiation. These data are consistent with earlier results using an antibody to deplete Gr-1+ leukocytes and indicate that radiation can inhibit the growth of certain tumors indirectly without direct effects on the tumor cells or the tumor bed.

Animals↗
PubMed1996

Neuronal and non-neuronal localization of acid sulfated glycosaminoglycans (sGAG) and chondroitin proteoglycans in the rat medulla oblongata.

Acid sulfated glycosaminoglycans (sGAG) and chondroitin proteoglycans have been biochemically and immunohistochemically demonstrated in certain cortical areas of the CNS. Such molecules display an important role in cerebral function, modulating cell adhesion, migration and signal neuromediation. In the present study we have evidenced the presence of sGAG using the colloidal iron method and C0S, C4S- and C6S-proteoglycans by the immunohistochemical pre-embedding PAP method. Our results have demonstrated the presence of such molecules in several structures of nervous (axon terminals, neuronal bodies, dendrites) and non-nervous nature (glial processes, capillaries). This fact led us to suggest that the chondroitin localizations advocate for their different functions. In their various localization exist distinct proteoglycans constituted by chondroitins with diverse concentrations and other attached radicals.

Animals↗
PubMed1996

Bowel resection and neurotensin treatment. Histochemical study of neurotensin-like and somatostatin-like immunoreactivities and receptors.

The influence of a bowel-trophic neurotensin (NT) treatment (13 days, 300 micrograms/kg/every 12 hrs.) on neurotensin-like immunopositive structures (neurons, fibres and epithelial-N-cells) and the neurotensin receptors (NTr) in the residual bowel after resection (90% small bowel or 75% colon) in the rat was studied using histochemical methods. Somatostatin-like (ST) immunopositive structures (neurons, fibres and epithelial-D-cells) and somatostatin receptors (STr) were also studied, comparatively. The results displayed a general increase of N-cells (11-17%) but not of D-cells, and a higher degree of variability section-to-section in the NT and ST immunopositive nervous structures (without increased density) after both resections, both with or without NT treatment. Receptors did not change after the small bowel resection but the colon resection and/or the NT treatment produced variations in the NT binding (from -24.3 to +16.85) in different intestinal regions. In a general sense, the variations among 1) the controls, 2) the resected animals, and 3) the resected and NT-treated animals, were of less extent (< or = 24%) than previously supposed for explaining the trophic effect of NT. Our results: a) confirm the autonomy, injury-resistance and tendency to maintain the physiological features of the bowel in very diverse situations; b) open new questions on both, the neurotensinergic changes after bowel resection and the mechanisms of the trophic effect of NT treatment, and c) suggest that, when neurotensin was applied as a trophic treatment in the cases of the need of a bowel resection, no important neurotensinergic or somatostatinergic side effects should be expected in the remaining bowel. However, the higher degree of variability section-to-section after surgery in the nervous structures was not modified by the NT treatment. This fact, and the different response of various intestinal regions to the NT treatment, suggest that functional problems in the remaining bowel could be maintained despite the growth of the mucosa induced by the NT treatment.

Animals↗
PubMed1995

Spatial and temporal control of gene therapy using ionizing radiation.

Activation of transcription of the Egr-1 gene by X-rays is regulated by the promoter region of this gene. We linked the radiation-inducible promoter region of the Egr-1 gene to the gene encoding the radiosensitizing and tumoricidal cytokine, tumour necrosis factor-alpha (TNF-alpha) and used a replication-deficient adenovirus to deliver the Egr-TNF construct to human tumours growing in nude mice. Combined treatment with Ad5.Egr-TNF and 5,000 cGy (rad) resulted in increased intratumoral TNF-alpha production and increased tumour control compared with treatment with Ad5.Egr-TNF alone or with radiation alone. The increase in tumour control was achieved without an increase in normal tissue damage when compared to tissue injury from radiation alone. Control of gene transcription by ionizing radiation in vivo represents a novel method of spatial and temporal regulation of gene-based medical treatments.

Animals↗
PubMed1994

Pyritinol facilitates the recovery of cortical cholinergic deficits caused by nucleus basalis lesions.

The effect of a nootropic, Pyritinol, on the recovery of cortical cholinergic deficits induced by injury of the nucleus basalis has been tested on two groups of unilateral quisqualic acid nbM-lesioned rats. The first group had a 30 nmol lesion producing a cortical cholinergic impairment at 21 days, with a spontaneous recovery at 45 days. The second group had a 50 nmol lesion that produced a deeper cholinergic deficit, which did not recover at 45 days. Pyritinol enhanced the recovery in the 30 nmol group of animals on the 21st day after surgery. The recovery was measured as an increase in the activities of acetylcholinesterase (AChE), choline acetyltransferase (ChAT) and the high affinity choline uptake system, and the histochemical densities of the cortical AChE network and the M2 receptor. Histochemical analysis of the nbM enabled cortical recovery to be related to the number of surviving neurons and also to their hypertrophy and AChE-ChAT hyperactivity. Pyritinol enhanced recovery in 30 nmol lesioned animals but in the other group, with a lower number of surviving neurons and a lower ability of the cells to become hypertrophic, the drug was unable to promote cortical recovery.

Animals↗
PubMed1994

Pulmonary carcinoma metastatic to the larynx.

Metastases to the larynx from distant primaries are rare. We report a case of a pulmonary epidermoid carcinoma metastatic to the larynx that simulated a primary cancer. A review of the literature showed nine previously reported cases of pulmonary metastases to the larynx--only two of them were epidermoid carcinomas. Treatment of a secondary lesion in the larynx is justified only when other organs have not been affected. The diagnostic and therapeutic considerations of this condition are discussed.

Carcinoma, Squamous Cell↗
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↗