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Biomedical subjects

D del Castillo

Publications and source records attributed to D del Castillo.

7 recordsLinked to original sources
PubMed1995

The pressor effect of recombinant human erythropoietin is not due to decreased activity of the endogenous nitric oxide system.

In a subset of dialysis patients, erythropoietin (rHuEpo) treatment exacerbates hypertension. The mechanism of this pressor effect is unknown; however, it has been suggested that decreased endogenous nitric oxide (NO) activity may play a role. To explore this hypothesis, Sprague-Dawley rats were given rHuEpo (150 U/kg s.c. three times per week) or corresponding vehicle. Blood pressure, haematocrit, and urinary excretion of the stable NO metabolites, nitrite (NO2) and nitrate (NO3), were determined at baseline and 3 weeks. After 3 weeks of rHuEpo treatment there was a significant increase in blood pressure and haematocrit, while in vehicle-treated rats blood pressure and haematocrit remained at basal levels. Urinary excretion of NO2+NO3 increased compared to basal in rHuEpo, but not vehicle rats. Thus in normal rats rHuEpo does have a significant pressor effect, but this is not associated with decreased activity of the endogenous NO system. Thus decreased endogenous NO activity is not responsible for rHuEpo-associated hypertension. These data further suggest that endogenous NO activity is increased in rHuEpo-treated rats, perhaps as a counter-regulatory mechanism that limits the pressor effect. Whether this mechanism is active in the setting of rHuEpo-treated chronic renal failure in humans is unknown.

Animals↗
PubMed1995

Four-week oral toxicity study of 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in uremic rats.

A short-term oral toxicity study of 1,2-dimethyl-3-hydroxypyrid-4-one (L1), a promising oral chelating agent for the treatment of iron and aluminum overload, was carried out in uremic rats. L1 was administered to male uremic rats by gastric intubation at 0, 20, 40, 80 or 160 mg/kg/d for 4 w. Body weight and food and fluid intake were monitored daily. Complete hematologic examinations, serum biochemical parameter determinations and histological examinations were carried out. Although body weight gain was significantly reduced at 80 and 160 mg/kg/d, there were no effects of L1 on food and fluid consumption. There were no significant differences between controls and L1-treated groups in most of the hematological and biochemical parameters analyzed. No significant dose-dependent changes in relative organ weights were noted. The non-observed-adverse-effect level (NOAEL) for L1 in uremic rats was 40 mg/kg/d. According to the results of this study, uremia did not increase the toxic effects of L1.

Administration, Oral↗
PubMed1994

Comparative aluminium mobilizing actions of several chelators in aluminium-loaded uraemic rats.

The relative effectiveness of deferoxamine (DFO), 1,2-dimethyl-1,3-hydroxypyrid-4-one (L1), and citric and succinic acids in mobilizing and promoting excretion of aluminium (Al) were compared in female uraemic rats which had previously received aluminium nitrate nonahydrate i.p. in a daily dose of 45 mg kg-1 for 3 weeks (5 days/week). Chelators were administered s.c. at doses equal to one-eighth of their respective LD50 for five days. L1 was also given p.o. in doses of 200 mg kg-1 day-1. Total urines were collected 24 h after each chelator administration. Total urinary Al excreted over the 5-day period, expressed as mg kg-1, were: controls, 3.4; DFO-treated, 4.5 (P < 0.05); citric acid-treated, 3.7; and succinic acid-treated, 2.7. Although the daily amounts of Al excreted into urine by L1-treated rats were significantly higher (P < 0.001) than those of the controls, most animals died during the period of treatment. Measurements of Al in selected tissues 24 h after the last administration of each chelator revealed that none of the compounds significantly altered the Al concentration in bone, kidney, and brain, whereas only DFO and succinic acid significantly reduced the levels of Al in spleen. Moreover, L1 (given s.c. or p.o.) and citric acid treatment led to a significant reduction in the liver Al burden. These results indicate the need for further investigations to determine the toxicity and the therapeutical safety margins of L1.

Aluminum↗
PubMed1993

Endotoxin-induced pulmonary dysfunction is prevented by C1-esterase inhibitor.

In septic shock, hypotension, disseminated intravascular coagulation, and neutrophil activation are related to the activation of the blood coagulation contact system. This study evaluates in dogs the effect of the C1-esterase inhibitor (C1-INH), a main inhibitor of the blood coagulation contact system, on the cardiovascular and respiratory dysfunction associated with endotoxic shock. Two groups were included: controls, which received Escherichia coli endotoxin, and a C1-INH group in which C1-INH was infused before E. coli endotoxin administration. In both groups, endotoxin produced hypodynamic shock; however, the decrease in the systolic index and the ventricular systolic work indexes were greater in controls than the C1-INH group. In controls, the arterial O2 partial pressure decreased by 30% and the alveolo-arterial O2 difference increased by 625%, these parameters remained unchanged in the C1-INH group. Hypoxemia was associated with increased intrapulmonary shunt, decreased blood coagulation contact factors, and decreased C3c. In contrast, C1-INH administration prevented endotoxin-induced hypoxemia, the increase in intrapulmonary shunt, and the decrease in blood coagulation contact factors. This study shows that, in dogs with endotoxic shock, pulmonary dysfunction is associated with an activation of the blood coagulation contact phase system. An inhibition of this system by C1-INH prevented the hypoxemia induced by endotoxic shock.

Animals↗