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Biomedical subjects

J Castro

Publications and source records attributed to J Castro.

At least 109 records · Page 6Linked to original sources
PubMed1991

Adjuvant treatment in stage I and II malignant melanoma: a randomized trial between chemoimmunotherapy and immunotherapy.

A randomized trial comparing chemoimmunotherapy (bacillus Calmette-Guérin + chemotherapy) and immunotherapy (bacillus Calmette-Guérin alone) was carried out in high-risk stage I and II malignant melanoma patients. Eight-two evaluable patients were included. The follow-up median duration was 11 years. Recurrent melanoma developed in 28 patients (34%). The overall survival rate was 76% at 5 years and 65% at 10 years. There were no statistical differences in survival probability or disease-free survival (DFS) probability between the two treatment groups. Survival and DFS were also analyzed in relation to various prognostic factors. Statistically significant differences were only seen in a subset of 33 patients with lower limb malignant melanoma, the prognosis being better for the chemoimmunotherapy group in this location. Because of the small number of patients in each group, a week positive effect of either of these two treatments cannot be ruled out. Chemoimmunotherapy only seems to improve the prognosis of stage I or II malignant melanoma of the legs.

Adult↗
PubMed1991

Comparison of the effects of a single dose and of four six-monthly doses of ivermectin on adult Onchocerca volvulus.

Adult Onchocerca volvulus worms, extracted from nodules of Guatemalans by collagenase digestion, were examined whole and by histological techniques. One group of persons received a single 150 micrograms/kg dose of ivermectin; two other groups (one with older and one with younger nodules) received four similar doses of ivermectin at 6-month intervals. For each group, there were comparable untreated controls. All nodules were removed six months after the last dose. After a single dose, the only significant difference from the controls was in the decreased proportion of female worms producing live microfilariae. After four doses, there were significant increases in the proportions of moribund/dead female worms and of live uninseminated females, when compared with the corresponding controls. There were also fewer male worms present, but this difference was not significant. Six months after the conclusion of the 4-dose regimen, the proportion of female worms producing live microfilariae was significantly lower than in the groups that had received a single dose.

Animals↗
PubMed1990

Simultaneous stimulation of fatty acid synthesis and oxidation in rat hepatocytes by vanadate.

When added to the hepatocyte incubation medium, vanadate increased the rate of fatty acid synthesis de novo as well as the activity of acetyl-CoA carboxylase, whereas it had no effect on the activity of fatty acid synthase. On the other hand, and despite elevating the intracellular levels of malonyl-CoA, vanadate diverted exogenous fatty acids into the oxidation pathway at the expense of the esterification route. This was concomitant to an increase in carnitine palmitoyltransferase I activity. All these effects were not significantly different between periportal and perivenous hepatocytes and were also evident in cells incubated in Ca2(+)-free medium. Nevertheless, Ca2+ ions enhanced carnitine palmitoyltransferase I activity in isolated liver mitochondria. In addition, the effects of vanadate on acetyl-CoA carboxylase and carnitine palmitoyltransferase I were only evident in a permeabilized-cell assay, disappearing upon cell disruption and isolation of the corresponding cell subfraction for enzyme assay. Results show that vanadate exerts specific insulin-like and non-insulin-like effects on hepatic fatty acid metabolism, and suggest that the intracellular concentration of malonyl-CoA is not the only factor responsible for the regulation of the fatty-acid-oxidative process in the liver.

Acetyl-CoA Carboxylase↗
PubMed1990

[Primary malignant melanoma of the skin. Retrospective study of 375 cases. Clinical aspects and histology].

The clinical and histologic features of 375 cases of primary malignant melanomas of the skin diagnosed and/or treated in the Hospital Clinic i Provincial (Barcelona, Spain) over a seven years period (1981-1987) were evaluated. The analysis of data showed many differences between these cases and those previously reported by us or from other countries. Sex incidence showed an increased frequency in women (58%), and a high incidence on lower limb in female (26% of all cases). Superficially spreading melanoma was the most common type (58%), followed by nodular melanoma (27%), acral lentiginous melanoma (8%) and lentigo maligna melanoma (6%). 57% of cases were diagnosed when the tumor thickness indicated a moderate or high-risk.

Adolescent↗
PubMed1990

Zonal heterogeneity of the effects of chronic ethanol feeding on hepatic fatty acid metabolism.

Periportal and perivenous hepatocytes were isolated from rats fed a high-fat, ethanol-containing diet to investigate the acinar heterogeneity of the effects of prolonged ethanol administration on lipid metabolism. Chronic feeding of ethanol caused a rather selective accumulation of triacylglycerols in the perivenous zone of the liver. In control animals the rate of lipogenesis and the activity of acetyl-CoA carboxylase were higher in perivenous than in periportal hepatocytes, whereas the rate of fatty acid oxidation and the activity of carnitine palmitoyltransferase I were higher in periportal than in perivenous cells; however, no zonation was evident for very-low-density-lipoprotein-lipid secretion. Prolonged ethanol administration abolished the zonal asymmetry of the lipogenic process and inverted the acinar distribution of the fatty acid-oxidative process (i.e., in ethanol-fed animals the rate of fatty acid oxidation and the activity of carnitine palmitoyltransferase I were higher in perivenous than in periportal hepatocytes). Moreover, chronic feeding of ethanol led to a marked and selective inhibition of very-low-density-lipoprotein-triacylglycerol secretion by the perivenous zone of the liver. Nevertheless, no zonal differences were observed between control and ethanol-fed animals with respect to the effects of acute doses of ethanol and acetaldehyde on lipid metabolism. In conclusion, our results show that chronic ethanol intake produces important alterations in the acinar distribution of the different fatty acid-metabolizing pathways.

Alcohol Drinking↗
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↗