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Biomedical subjects

J Castro

Publications and source records attributed to J Castro.

At least 145 records · Page 8Linked to original sources
PubMed1989

Ethanol increases the sensitivity of carnitine palmitoyltransferase I to inhibition by malonyl-CoA in short-term hepatocyte incubations.

The sensitivity of carnitine palmitoyltransferase I to inhibition by malonyl-CoA was increased in mitochondria isolated from rat hepatocytes incubated with ethanol. This effect was mimicked by incubation of hepatocytes with acetaldehyde or by preincubation of isolated mitochondria with malonyl-CoA. Both ethanol and acetaldehyde increased the intracellular concentration of malonyl-CoA. Results suggest that the ethanol-induced elevation of intracellular malonyl-CoA levels may be responsible for the enhanced sensitivity of carnitine palmitoyltransferase I to inhibition by malonyl-CoA.

Acetaldehyde↗
PubMed1989

Eating attitudes, sociodemographic factors and body shape evaluation in adolescence.

The Eating Attitudes Test (EAT) and another questionnaire aimed at sociodemographic and body shape information were administered to an adolescent population of 1554 students from Barcelona in the 12-19 age group. The highest scores on EAT were obtained by girls, older adolescents, overweight adolescents, adolescents practising restrictive diets, adolescents considering themselves obese and those wishing to modify their body size. The same characteristics were associated with EAT scores higher than 30 (the cut-off score, established by the authors of the questionnaire, above which the anorexic population is placed). Results are analysed in terms of sociocultural pressures on adolescents, particularly females, who are subjected to the 'culture of slenderness'.

Adolescent↗
PubMed1988

Effects of endurance exercise on carnitine palmitoyltransferase I from rat heart, skeletal muscle and liver mitochondria.

Prolonged physical exercise increased the activity of carnitine palmitoyltransferase I in rat heart and skeletal muscle mitochondria, whereas enzyme sensitivity to inhibition by malonyl-CoA remained unchanged. Nevertheless, inhibition of carnitine palmitoyltransferase I activity by small decreases in pH was attenuated in heart and skeletal muscle mitochondria from exercised animals. Liver enzyme did not suffer any alteration by endurance exercise.

Acyltransferases↗
PubMed1988

Dependence with nutritional status of the ethanol effects on fatty acid metabolism in rat hepatocytes.

1. The effects of ethanol on fatty acid synthesis, esterification and oxidation were studied in hepatocytes isolated from fed and 24 hr fasted rats. 2. [3H]H2O was preferentially incorporated into the glycerol backbone of triglycerides and phospholipids. Addition of ethanol markedly increased the incorporation of this label in both classes of glycerolipids; the increase was higher in fasted rat hepatocytes, both in the glycerol backbone and acyl groups of glycerolipids. 3. Ethanol increased [U-14C]palmitate incorporation into triglycerides only in hepatocytes from fasted rats. 4. [14C]CO2 and total acid soluble product formation from [1-14C]palmitate resulted inhibited by ethanol both in the fed and the fasted state.

Animals↗
PubMed1988

Treatment of diabetic neovascular glaucoma by panretinal ablation and trabeculectomy.

The efficacy of treating diabetic neovascular glaucoma by panretinal cryotherapy and trabeculectomy was studied over post-operative periods of 6-24 months in 26 selected eyes (8 acute cases and 18 chronic cases). The only complications attributable to surgery were slight hyphemas. Mean pre-operative intraocular pressure (IOP) among the acute cases was 48.8 +/- 9.9 mmHg. After 1 year, IOP was under control (IOP less than or equal to 22 mmHg) in 6 eyes (75%) (2 patients needed hypotensive drugs and another required surgery again). Among the chronic cases, pre-operative IOP was 30.1 +/- 2.1, while a year after surgery IOP was under control (IOP less than or equal to 22 mmHg) in 14 patients (77%) (5 of these needed hypotensive medication and 2 a second operation). The visual acuity (VA) of 66% of the chronic cases was unaltered a year after surgery. The VA of 63% of the acute cases was better a year after surgery. The VA of the 8 patients re-examined 2 years after surgery had deteriorated in spite of their IOP being under control.

Adult↗
PubMed1987

Ethanol feeding to rats reversibly decreases hepatic carnitine palmitoyltransferase activity and increases enzyme sensitivity to malonyl-CoA.

The effects of prolonged ethanol feeding on both carnitine palmitoyltransferase I activity and enzyme sensitivity to inhibition by malonyl-CoA were studied in rat liver, heart, skeletal muscle and kidney cortex mitochondria. Heart and skeletal muscle enzymes showed the highest specific activity and sensitivity to malonyl-CoA. Carnitine palmitoyltransferase I in extrahepatic tissues showed no changes on ethanol feeding. Only the liver enzyme activity was altered after long term ethanol administration, by suffering a progressive decrease in activity and a parallel increase in sensitivity to malonyl-CoA. These alterations reversed after 10 days of ethanol withdrawal. These results are discussed in relation to the control of carnitine palmitoyltransferase I and the effects of ethanol on fatty acid metabolism.

Acyl Coenzyme A↗
PubMed1987

Short and long term effects of ethanol on glycerolipid synthesis from palmitate in fasted rat hepatocytes.

Prolonged ethanol administration to rats increased the rates of glycerolipid synthesis from added [U-14C]palmitate in fasted hepatocytes; this increase was more than 2-fold in triglyceride synthesis. Prolonged ethanol administration to rats completely eliminated the acute ethanol-induced increase in triglyceride synthesis from palmitate in hepatocytes from fasted rats. This adaptive change occurred in a short initial period of about 10 days of ethanol feeding. In hepatocytes from fasted control rats, addition of ethanol produced a rapid and strong increase in the concentration of glycerol 3-phosphate. By contrast, this acute effect of ethanol disappeared in hepatocytes from fasted alcoholic rats after a prolonged--5 weeks--administration of ethanol in a liquid diet.

Alcoholism↗
PubMed1987

Increased uptake and retention of rhodamine 123 by mitochondria of old human fibroblasts.

Binding of the fluorescent dye R123 by a variety of mammalian cells has been shown to be dependent on the high transmembrane potential maintained in functional mitochondria. Recent studies in our laboratory have shown that old human fibroblasts (HF) bind and retain more R123 than young HF. In an effort to determine whether this difference in R123 uptake indeed reflected a difference in mitochondrial transmembrane potential, drugs known to disrupt the transmembrane potential of mitochondria were used to monitor the R123-mitochondria interaction of young and old HF. Distinct differences indicating that old HF maintain a higher mitochondrial transmembrane potential were observed. More significantly, perhaps this difference reflects an age-related change(s) in the structure and/or function of mitochondria.

Cell Line↗
PubMed1987

Plasma cells within the infiltrate of primary cutaneous malignant melanoma of the skin. A confirmation of its histoprognostic value.

Plasma cells within the infiltrate of primary cutaneous malignant melanoma have been reported as a valuable criterion for the prediction of lymph node metastases. In order to evaluate plasma cells, their prognostic significance and their relationship with other clinical and histological parameters, 132 cases of malignant melanoma (29 plasma cell positive and 103 plasma cell negative) were studied. The Breslow thickness, location, and ulceration were the variables related to the presence of plasma cells. The most important variables in predicting survival were lymph node involvement, clinico-pathological type, age, plasma cells, and lymphatic emboli. The most important variables for disease-free interval were lymph node involvement, plasma cells, and age.

Adolescent↗
PubMed1987

Peer perceptions of hyperactivity and medication effects.

This study focused on peer sensitivity to differences in social behaviors between hyperactive and normal comparison peers and, especially, to medication-related behavioral differences. In Study 1, normal sixth graders rated videotapes of normal and hyperactive boys playing a social interaction game. Half of the hyperactive boys were taking methylphenidate, and the other half placebo. In Study 2, fourth- and sixth-grade children rated a different sample of hyperactive boys (seen on both methylphenidate and placebo) playing the same interaction game. Hyperactive boys taking placebo were perceived as exhibiting more externalizing problem behaviors than either medicated hyperactive boys or comparison boys. The medication effects were robust, spanning many behavioral domains and emerging consistently across the 2 studies. There were few grade or gender differences. Discussion focused on children's detection of treatment-related differences in the social behaviors of their peers, as well as on the imperfect relation between social behavior and social standing.

Adolescent↗
PubMed1987

Stimulation by ethanol of triglyceride synthesis in fasted rat hepatocytes is dependent on the increase of glycerol 3-phosphate levels.

Ethanol was without effect on the incorporation of [U-14C]palmitate into triglycerides in hepatocytes from fed rats, but significantly increased triglyceride synthesis in hepatocytes from fasted rats. Glycerol alone induced a similar increase, but brought about a strong synergistic stimulation when added with ethanol. Glycerol 3-phosphate levels were also determined. It is concluded that only in the fasted state the ethanol-induced increase of glycerol 3-phosphate concentration becomes determinant for the stimulation of triglyceride synthesis from exogenous palmitate.

Animals↗
PubMed1986

Differences in glycerolipid synthesis and insulin regulation in rat hepatocytes and adipocytes.

Glycerolipid synthesis was studied by determining radioactive incorporation from either [1-14C] acetate or [U-14C] palmitate. Glycerolipid synthesis in adipocytes, mainly from exogenous palmitate, was preferentially directed to the formation of triacylglycerols, whereas in hepatocytes triacylglycerols and phospholipids were synthesized at similar rates. Insulin stimulated glycerolipid synthesis from acetate in both types of cells, being triacylglycerols more significantly increased than phospholipids. The most relevant difference was the finding that in adipocytes insulin strongly stimulated the formation of diglycerides, apparently from phosphatidate, whereas in hepatocytes insulin only slightly increased diglyceride levels. A possible role of diacylglycerol in insulin action in adipocytes, but not in hepatocytes, is also discussed.

Acetates↗