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Biomedical subjects

S Garcia

Publications and source records attributed to S Garcia.

At least 145 records · Page 8Linked to original sources
PubMed1990

Mn2(+)-activated aspartate aminopeptidase activity, subcellular localization in young and adult rat brain.

The levels of soluble and membrane-bound aminopeptidase activities were assayed in subcellular fractions from young (4 weeks old) and adult (20 weeks old) rat brains, using Asp-2-naphthylamide as substrate. The young rats showed the highest soluble and membrane-bound levels of activity in the microsomal fraction but no differences among fractions were found at 20 weeks of age. The membrane-bound activity was significantly higher than the soluble one in all subcellular fractions of young rats. Soluble activity of the homogenate and the mitochondrial fraction was significantly increased in adult animals when compared to that of younger ones.

Aging↗
PubMed1990

Intrathoracic migration of a Kirschner wire.

Migration of Kirschner wires, Rush pins, etc., is well known. Such migrations usually follow a retrograde path and the wires protrude near the entry point. Occasionally migration occurs in another direction. We describe a case in which the Kirschner wire migrated from the shoulder to the thorax. Several factors caused this migration. This complication must be avoided by bending the free end of the wire, removing the osteosynthesis material as soon as possible and following up the patient for a long period.

Adult↗
PubMed1989

Idiopathic myelofibrosis terminating in erythroleukemia.

A 55-year-old woman with a one-year history of idiopathic myelofibrosis progressed to erythroleukemia. This is the first reported occurrence of erythroleukemia progression from idiopathic myelofibrosis. Certain patterns of leukemia transformation from myeloproliferative disorders are favored: Myeloblastic or myelomonocytic. The rare incidence of erythroblastic transformation is discussed.

Biopsy↗
PubMed1989

Sodium azide mutagenesis in mammals: inability of mammalian cells to convert azide to a mutagenic intermediate.

Sodium azide is unique among mutagens. It is highly mutagenic in many plant and bacterial species but marginally mutagenic in mammalian cells. A possible explanation for this difference in mutagenic efficiency may lie in the inability of mammalian cells to convert azide to the putative ultimate mutagen. Normal human fibroblasts and Chinese hamster cells or cell-free extracts from these cell lines were treated with azide and the sonicates tested for mutagenicity in Salmonella strain TA1530. The data suggest that neither cell line was capable of converting azide to a mutagenic intermediate. In addition, both cell lines expressed the enzyme O-acetylserine(thio)-lyase which is responsible for the conversion of azide to azidoalanine, the putative mutagenic intermediate. Although mammalian cells possess the enzyme responsible for the conversion of azide to azidoalanine, they appear incapable of converting azide into a mutagenic intermediate in appreciable quantities. Further, the data support the conclusion that azide may be further modified in mammalian cells to an intermediate that is not genotoxic.

Animals↗
PubMed1989

Genotoxic potential of crown ethers in Salmonella typhimurium.

Macrocyclic polyethers (crown ethers) are a family of compounds which possess the ability to transport ionic species across natural and artificial membranes. Because of this characteristic, they have wide applications in industry and are being investigated for their potential as pharmacologic agents. However, these compounds are highly cytotoxic in both prokaryotes and eukaryotes. Because of the cytotoxicity of crown ethers, an investigation of the potential genotoxicity of these compounds in Salmonella typhimurium was initiated. Several unsubstituted and substituted crown ethers did not induce a genotoxic response in S. typhimurium strains TA100, TA1530, TA98 and TA1537 either with or without rat liver S9 mixture. The data support the conclusion that the toxicity of these compounds is probably not due to an interaction with nucleic acid to induce premutagenic lesions and they do not appear to be genotoxic in prokaryotes.

Ethers, Cyclic↗
PubMed1988

Radioautographic method for quantifying regional monoamine innervations in the rat brain. Application to the cerebral cortex.

Conditions leading to selective and complete labeling of the noradrenaline (NA) and serotonin (5-HT) innervations in rat cerebral cortex were sought by incubating 200-micron-thick whole hemisphere slices with various combinations of tritiated monoamines and uptake blockers at different concentrations in the presence of a monoamine oxidase inhibitor. After fixation with glutaraldehyde, post-fixation with osmium tetroxide and flat-embedding in Epon, 4-micron-thick sections of the entire slices were radioautographed by dipping in nuclear emulsion. As previously reported, dopamine (DA) terminals could be specifically visualized and counted following incubation with 1 micron [3H]DA and 5 microM desipramine (DMI) with or without 5 microM citalopram (CITAL). The number of NA terminals could thus be obtained by subtracting DA varicosities from the total number of sites labeled in adjacent slices incubated without DMI but in presence of CITAL to eliminate some interspecific labeling of 5-HT terminals. NA terminals could also be identified exclusively and counted after labeling with 1 microM [3H]NA in the presence of 10 microM benztropine. 5-HT terminals were specifically detected after incubation with 1 microM [3H]5-HT in the presence of 10 microM non-radioactive NA. The labeled varicosities were counted in areas FR1 and PAR1 of the frontal and the parietal neocortex, respectively, with the aid of a microcomputer-based image analysis system. DA varicosities were concentrated mainly in layer VI of these regions and were more numerous in the frontal than the parietal area. NA terminals were equally distributed in the two regions but approximately twice as numerous in layer I than subjacent layers. The 5-HT innervation also showed a comparable overall density in the two cortical regions but with a differing intracortical distribution. In the frontal area, 5-HT terminals were slightly more concentrated in layer I (1.3-fold) than underlying layers where they were rather uniformly distributed. In the parietal area, layer I was again the most densely innervated (1.8 times the average), but a second zone of higher density (1.5 times average) was present in the outer part of layer V. The remaining layers showed lower numbers of 5-HT terminals than in the frontal region. To obtain absolute estimates of these innervation densities, the number of detected varicosities was assessed experimentally as a function of radioautographic exposure time and of histological section thickness, and their 'equivalent circle diameter' was measured in electron microscope radioautographs.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Treatment of hypertensive crisis in children with nifedipine.

We report 31 episodes of hypertensive crises in children, managed with sublingual nifedipine at the following dosages: 10 mg in children with body weight (BW) higher than 20 kg, 5 mg in children with BW between 10 and 20 kg, and 2.5 mg in children with BW below 10 kg. The mean initial blood pressures were 161.41 mm Hg for the systolic pressure (mSBP) and 111.25 mm Hg for the diastolic pressure (mDBP). After nifedipine, both the mSBP and the mDBP decreased, with onset of effect five minutes after dosage and maximum decrease at 60 min (mSBP 134.93 mm Hg, mDBP 79.23 mm Hg, for decreases of 16.4 and 28.7%, respectively), and this effect persisted for 180 min. Blood pressure increased again from min 240 to min 360, yet without reaching the initial levels. One case did not respond to the first dose of nifedipine and required a second one. The effect of nifedipine was more pronounced on the DBP than on the SBP, and greater reductions of both pressures were achieved in the cases with higher initial readings. No side of medication were observed in our patients.

Administration, Sublingual↗
PubMed1988

Slow infusion of vincristine in the treatment of refractory thrombocytopenic purpura.

Eight patients with idiopathic thrombocytopenic purpura (ITP), who were refractory to glucocorticoid therapy, were given slow infusions of vincristine (VCR) over a 4- to 6-hour period at weekly intervals for 4 weeks. Three patients showed a return to normal platelet counts maintained for 3 months or longer. A transient recovery was observed in 1 patient and a partial response was observed in 3 patients. All patients tolerated therapy well, without side effects. In conclusion, therapy with slow infusion of VCR can be effective in refractory ITP.

Adult↗
PubMed1988

Mitotic activity of the endothelial vascular cell in the immature retina.

We studied the ultrastructural characteristics of the mitoses of the retinal vascular endothelium during normal vasculogenesis in the immature retina of 45 newborn albino rats, from birth to the end of the 1st month of postnatal development. For the first time mitotic phenomena in the endothelial cells to the adjacent endothelium during all mitosis stages. Direct budding from the pre-existing vessels seems to be the actual mechanism of growth of the retinal vessels in the holangiotic immature retina.

Animals↗
PubMed1987

Wood degradation by white rot fungi: cytochemical studies using lignin peroxidase-immunoglobulin-gold complexes.

Using an anti-lignin peroxidase antiserum-protein A-gold complex, we found lignin peroxidase mainly intracellularly in several white rot fungi colonizing sawdust under laboratory conditions. This enzyme was also present in fungi found in naturally decayed wood. However, in all cases, lignin peroxidase was located mainly inside the fungal cells. Labeled lignin peroxidase did not bind to the lignocellulosic samples tested, with the exception of poplar milled-wood lignin. These results are discussed in relation to the role of lignin peroxidase during wood degradation.

Journal Article↗