PubMed Health⌕ Search

Biomedical subjects

M García

Publications and source records attributed to M García.

At least 307 records · Page 17Linked to original sources
PubMed1986

[Effects of partial hepatectomy on various blood and hepatic parameters in the rainbow trout (Salmo gairdnerii, Rich.)].

After 36% of hepatic mass removal , rainbow trout recovered its initial liver weight in 20-30 days, i.e., with a regeneration rate clearly lower than in mammals. During early regeneration process hematocrit index and hemoglobin content were slightly decreased, but both parameters rapidly reached their normal values. The evolution of both glycaemia and hepatic glycogen content supported the idea of the existence of a late regeneration wave, which, in this case, could begin at about the 20th post-operative day.

Animals↗
PubMed1985

[Leukemic infiltration in the anterior chamber of the eye].

Leukaemic infiltration of the anterior chamber of the eye (hypopyon and corneal opacity) was the only sign of relapse in two girls with acute lymphoblastic leukaemia who had been off treatment for one and three years. The malignant cells had probably been present in the eye since the onset of the disease. The anterior segment of the eye may be a pharmacologycal "sanctuary" in patients with ALL. The response to radiotherapy was good but this treatment should be coupled with systemic chemotherapy and CNS prophylaxis.

Anterior Chamber↗
PubMed1985

Effects of manganese chloride on the outward currents in frog atrial trabeculae.

The effects of MnCl2 on outward currents in frog atrial muscle were investigated under voltage-clamp conditions. MnCl2 (3 mmol/L), which completely abolished the slow inward current, produced a decrease in the outward background current (Ib) at potentials positive to -50 mV. The delayed outward current (Ix, time dependent) was not altered by Mn. "Isochronic activation curves" for Ix and decay of current tails at -40 mV remained unaffected after Mn. Effects on Ib probably reflect a decrease in IK1 related to the decrease in Ca influx as well as a reduction in the Na-Ca exchange current.

Action Potentials↗
PubMed1985

Kerosene aerosol induces guinea-pig airway hyperreactivity to acetylcholine.

Kerosene aerosol (32.5 mg/l; 20 min), when administered to guinea pigs 1 h before exposure to acetylcholine (Ach), induced potentiation of cumulative dose-response curve of this agonist on isolated tracheal strips as well as a decrease of the lethal doses of Ach. This enhanced response was absent or greatly reduced when kerosene aerosol was administered to guinea pigs 24 h previously or just before Ach challenge. This airway hyperreactivity was also lacking when carbachol or histamine were used as spasmogens instead of Ach. Possible explanations of these results are discussed.

Acetylcholine↗
PubMed1985

Induction of acetylcholinesterase inhibition in the guinea pig trachea by kerosene.

The effect of kerosene on in vivo and in vitro tracheal acetylcholinesterase (CHE) activity of guinea pigs has been investigated. Kerosene aerosol administered to guinea pigs during 20 min at a mean concentration of 20.4 mg/l elicited immediately, 1 h and 24 h later tracheal CHE inhibition by 30, 48.8, and 32.3% of control values (p less than 0.05). Kerosene at 1% concentration inhibited significantly, after 1 h of incubation in vitro, the CHE activity by 44.9% of control values. The tracheal CHE inhibition induced by kerosene could actually increase the acetylcholine concentration acting on smooth muscle of airways, and this partially explains the respiratory symptoms which are frequently observed after kerosene intoxication.

Animals↗
PubMed1985

Changes in body compartments on different types of haemodialysis.

Changes in plasma volume (PV), extracellular volume (ECV) and intracellular volume (ICV) were studied in seven patients on conventional haemodialysis (HD) and in six patients on stable hypertonic HD. Weight loss and ultrafiltration were similar in both groups. Before HD the spaces of 125RISA (PV), 35SO4Na2 (ECV) and 3H2) (total body water, TBW) were simultaneously determined ICV = TBW - ECV. At the end of HD the space of 35SO4Na2 was again tested. PV and ECV diminished more on conventional HD than on hypertonic HD, whereas ICV increased on conventional HD and decreased on hypertonic HD. The handling of plasma osmolality during HD is an effective method for modifying transcompartmental body fluid shifts in HD by distributing weight loss between intracellular and extracellular spaces allowing for a better maintenance of plasma volume.

Adult↗
PubMed1984

Gamma-glutamyl transpeptidase: a sensitive marker in DDT and toxaphene exposure.

Gamma-glutamyl transpeptidase (GGTP) activity in rat liver plasma membrane and blood serum was investigated as an analytical marker for studying acute and sub-chronic exposure to DDT and toxaphene. Twenty-four hours after a single oral dose of DDT (200 mg per kg body weight) or toxaphene (110 mg per kg body weight), GGTP activity increased two-fold in liver plasma membranes, followed by a return to normal values 48 h post-exposure. In addition, serum GGTP activity doubled following acute exposure to DDT or toxaphene, and remained elevated for 48 and 96 h, respectively. Following 2 months continuous exposure to either insecticide, serum GGTP activity levels increased to double that of control values. GGTP activity in liver plasma membranes was elevated 2.5-fold following the initial treatment with toxaphene (16.5 mg per kg body weight per day) and the activity remained high throughout the treatment period (120 days). Prolonged exposure with DDT (30 mg per kg body weight per day) did not produce any change in liver GGTP activity. Based on these results, it appears that GGTP activity could be used as a marker for acute DDT and toxaphene exposure.

Animals↗
PubMed1984

Epithelial reattachment after gingivectomy in the rat.

It is known that an epithelial reattachment occurs a few days after gingivectomy. Depending upon the surgical procedure and the animal species used, different times have been proposed to obtain a complete reattachment. Nevertheless, it is not known whether there is a correlation between the time required and the sequence of morphologic events involved in this process. To investigate this matter, gingivectomies were performed in the maxillary molars of rats. Specimens were taken 1 to 14 days after the operation and processed for light and electron microscopy. The new junctional epithelium appeared at the 5th day, but the earliest signs of reattachment complex formation were evident at the 8th day. Rudimentary hemidesmosomes and lamina lucida appeared in epithelial cells bordering remnants of fibrin. Anchoring filaments that formed between the earliest hemidesmosomes and the subjacent fibrin crossed the lamina lucida. Simultaneously, segments of lamina densa appeared. At the 11th day insertion of tonofilaments into the attachment plaques and insertion of anchoring filaments in the lamina densa were observed. At the 14th day, full development of the reattachment complex was evident.

Animals↗
PubMed1984

Role of the slow inward current during the repolarisation process in frog atrial trabeculae.

Voltage clamp experiments were performed to analyse the influence of the slow inward current (isi) on the repolarisation process in frog atrium. MnCl2 was used as isi blocker. The action potential was prolonged by depolarising pulses applied during the plateau. This was an expected result considering that, at positive potentials the time constant for isi inactivation increases. This effect was abolished by Mn ions which in turn block isi. The results suggest that inactivation of isi is of primary importance in determining the repolarisation rate. The action of Mn was not selective, since it reduced the background K current. This effect seems to be related to the decrease in Ca influx.

Action Potentials↗
PubMed1984

Physical exercise inducing electrophysiological changes in the atria: sympathetic-mediated effects?

Rats were subjected to long-term physical exercise by swimming and their hearts were examined electrophysiologically in order to identify relevant factors as mechanisms of protection from rhythm disturbances. The role of catecholamines was also studied using a chronically applied beta-adrenergic blocking drug, Practolol, or a catecholamine depleting drug, Reserpine. The results were compared with those obtained in rats similarly injected but kept in sedentary life. Action potential duration was found to be prolonged in trained animals regardless of the drug employed. Trained animals showed increments in the myocardial mass. Prolongation of the action potential coincided with lower values for maximum follow frequencies. It is suggested that the effects elicited could protect the heart against rhythm disturbances. The sympathetic nervous system seemed to play no important role.

Animals↗
PubMed1983

Isolation of sulphate transport defective mutants of Candida utilis: further evidence for a common transport system for sulphate, sulphite and thiosulphate.

Selenate-resistant mutants of Candida utilis were isolated. They did not take up sulphate while incorporation of an organic sulphur source, such as L-methionine, was similar to the wild-type strain. They grew poorly on sulphate, sulphite and thiosulphate and, as expected, grew well on methionine. Sulphite reductase activities of the mutants were similar to the wild type strain. The properties of these mutants support the view of a common transport system for sulphate, sulphite and thiosulphate.

Biological Transport, Active↗
PubMed1982

G6PD-Puerto Limón: a new deficient variant of glucose-6-phosphate dehydrogenase associated with congenital nonspherocytic hemolytic anemia.

A new glucose-6-phosphate dehydrogenase (G6PD) variant with total deficiency associated with congenital nonspherocytic hemolytic anemia was found in a Costa Rican family. The study of the partially purified enzyme revealed thermal instability, increased G6P affinity, abnormal pH optimum, increased utilization of analogues, and a chromatographic behavior that differs from all the variants previously described. Thus, this new variant was designated G6PD Puerto Limón.

Adult↗