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Biomedical subjects

J Castro

Publications and source records attributed to J Castro.

At least 127 records · Page 7Linked to original sources
PubMed1990

Long-term results of helium ion irradiation of uveal melanoma.

Between 1978 and 1988, 307 patients with uveal melanoma were irradiated using helium ions at Lawrence Berkeley Laboratory. The length of follow-up ranged from 1-115 months (median 42 months). The 5-year actuarial treatment results were: local control rate, 96.8%, determinate survival rate, 81%, freedom from distant metastases, 76%, eye retention rate, 83%, and risk of developing neovascular glaucoma, 36%. Long-term vision outcome was analyzed in 81 patients with a minimum follow-up of 5 years. Forty-seven percent of patients retained vision of 20/200 or better. The median change in vision was a loss of four lines on the standard eye chart. Thirty-eight percent of patients had visual acuity either improve or remain within two lines of their pretreatment vision. A multivariate analysis identified tumor size as the only independently significant risk factor affecting survival, development of neovascular glaucoma, or the risk of enucleation; no risk factor correlated with local recurrence. Tumor size, tumor-fovea distance, and pretreatment visual acuity were independently significant risk factors influencing vision outcome. These results confirm that helium ion irradiation is an effective treatment for uveal melanoma which combines high rates of local control, survival, and eye retention with a substantial likelihood of long-term vision preservation.

Adult↗
PubMed1990

Alterations in the regulatory properties of hepatic fatty acid oxidation and carnitine palmitoyltransferase I activity after ethanol feeding and withdrawal.

The effects of prolonged ethanol feeding on the regulatory properties of both hepatic fatty acid oxidation and carnitine palmitoyltransferase I activity (CPT-I) were studied in rats fed a high-fat diet containing 36% of total calories as ethanol (ethanol group) or an isocaloric amount of carbohydrate (control group). Prolonged ethanol feeding progressively decreased CPT-I activity and increased enzyme sensitivity and sensitization to inhibition by malonyl-CoA in liver mitochondria. Similarly, long-term ethanol feeding progressively increased the sensitivity of CPT-I, as well as that of fatty acid oxidation, to inhibition by 4-hydroxyphenylglyoxylate. Short-term addition of ethanol or acetaldehyde to the incubations markedly increased the sensitivity of CPT-I to inhibition by malonyl-CoA in a subsequent assay in hepatocytes isolated from ethanol-treated rats, but not in cells from control animals. This effect may be mediated by the ethanol- or acetaldehyde-induced increase of intracellular malonyl-CoA levels. The present results show that ethanol feeding to rats leads to profound alterations in the regulatory properties of hepatic CPT-I, which seem to be determinant for the decreased capacity of fatty acid oxidation by the liver in this state. Nevertheless, all the above-mentioned alterations of the fatty acid oxidative system were reversible, disappearing after 2 to 4 days of ethanol withdrawal.

Acetaldehyde↗
PubMed1990

Effects of multiple monthly doses of ivermectin on adult Onchocerca volvulus.

This paper assesses the effects on adult Onchocerca volvulus of monthly doses of ivermectin (150 micrograms/kg) given over 4, 8, and 12 months to patients in Guatemala. Nodules were removed 4 months after the last dose; the adult O. volvulus were extracted by collagenase digestion, studied by histological techniques, and compared with worms from untreated patients. Twelve monthly doses killed a proportion of the adult worms (12% of males and 22% of females), leaving the remainder relatively unaffected and the females slowly resuming embryogenesis. After 8 and 12 doses, a number of female worms had resumed embryogenesis in 1 genital tract only, and in 1 female a total degeneration of 1 ovary was seen. Ivermectin also led to a marked drop in the number of male worms in nodules. No serious adverse reactions occurred and the treatment was well accepted.

Animals↗
PubMed1990

[The admission and discharge criteria of a unit for critical patients].

Admission and discharge criteria for patients in an intensive care unit are controversial, especially in view of the fact that some patients derive no benefit from intensive care therapy while depriving others from a potential benefit. The general characteristics of patients in need of intensive care are discussed. Irreversibility of the underlying condition, the quality of "terminal patient" and other factors that may contraindicate admission to an intensive care unit are analyzed. Discharge criteria for patients not expected to derive further benefit from a prolonged stay in the unit are outlined.

Humans↗
PubMed1990

Ultrasonic forms of posterior staphyloma.

The most frequent deformations of the globe encountered in pediatric ophthalmology are staphylomas and colobomas. In this paper we reviewed 16 ultrasonographically diagnosed staphylomas and classified the ultrasonographic patterns produced by staphyloma cases into four types: (1) staphylomas involving the posterior pole but not the optic nerve head, (2) staphylomas involving the posterior pole and the optic nerve head, (3) peripapillary staphylomas, and (4) giant peripapillary staphylomas. Morphologic and ultrasonographic characteristics are described.

Eye Abnormalities↗
PubMed1989

Zonation of fatty acid metabolism in rat liver.

Fatty acid metabolism was studied in periportal and perivenous hepatocytes isolated by the method of Chen & Katz [Biochem. J. (1988) 255, 99-104]. The rate of fatty acid synthesis and the activity of acetyl-CoA carboxylase were markedly enhanced in perivenous hepatocytes as compared with periportal cells. However, the response of these two parameters to short-term modulation by cellular effectors such as the hormones insulin and glucagon, the phorbol ester 4 beta-phorbol 12 beta-myristate 13 alpha-acetate and the xenobiotics ethanol and acetaldehyde was similar in the two zones of the liver. In addition, perivenous hepatocytes showed a higher capacity of esterification of exogenous fatty acids into both cellular and very-low-density-lipoprotein lipids. Nevertheless, no difference between the two cell sub-populations seemed to exist in relation to the secretion of very-low-density lipoproteins. On the other hand, the rate of fatty acid oxidation was increased in periportal cells. This could be accounted for by a higher activity of carnitine palmitoyltransferase I and a lower sensitivity of this enzyme to inhibition by malonyl-CoA in the periportal zone. No differences were observed between periportal and perivenous hepatocytes in relation to the short-term response of fatty acid oxidation and carnitine palmitoyltransferase I activity to the cellular modulators mentioned above. In conclusion, our results show that: (i) lipogenesis is achieved at higher rates in the perivenous zone of the liver, whereas the fatty-acid-oxidative process occurs with a certain preference in the periportal area of this organ; (ii) the short-term response of the different fatty-acid-metabolizing pathways to cellular effectors is quantitatively similar in the two zones of the liver.

Acetyl-CoA Carboxylase↗
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↗