Search PubMed⌕ Search

Biomedical subjects

C Castillo

Publications and source records attributed to C Castillo.

At least 73 records · Page 4Linked to original sources
PubMed1998

alpha 1D-adrenoceptors contribute to the neurogenic vasopressor response in pithed rats.

The aim of the present study was to assess the role of vascular alpha 1D-adrenoceptors in the sympathetic vasopressor response in vivo. Specifically, we evaluated the effect of a selective alpha 1D-adrenoceptor antagonist, BMY 7378 (8-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-8-azaspiro(4,5)dec ane-7,9- dione 2HCl), on the vasopressor response induced by preganglionic (T7-T9) sympathetic stimulation in the pithed rat. The vasopressor response was dose-dependently sensitive to inhibition by intravenous BMY 7378 (0.1, 0.31, 1 and 3.1 mg/kg), doses of 1 and 3.1 mg/kg being equally effective. Like BMY 7378, 5-methylurapidil (0.1, 0.31, 1 and 3.1 mg/kg) antagonized the vasopressor response to spinal stimulation; doses of 1 and 3.1 mg/kg were also equally effective. In combination experiments, BMY 7378 (1 mg/kg, i.v.) and the alpha 1A-adrenoceptor antagonist, 5-methylurapidil (1 mg/kg, i.v.), showed an additive effect. The present results demonstrate that the alpha 1D-adrenoceptor subtype plays an important role in the pressor response to sympathetic nerve stimulation in the pithed rat, and confirm the participation of the alpha 1A-adrenoceptor subtype in the same response.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1998

Lidocaine accessibility to the open state of brain Na+ channels increases during development.

During postnatal brain development, the function of Na+ channels undergoes changes. We investigated at the single channel level whether the lidocaine sensitivity of the open state of brain Na+ channels changed during development and the underlying kinetic differences of the lidocaine-induced open channel block between brain and muscle Na+ channels. The lidocaine affinity for the open channel state was found to be about 30% higher in 15 day old than in newborn channels and reflected a higher binding rate constant in 15 day old channels. When compared with reported values from adult muscle Na+ channels, lidocaine blocked the open state of brain channels with about ten times higher potency and reflected a lower unbinding rate constant in brain channels. These results indicate that the conformations of the channel structures defining the lidocaine accessibility to its binding site must undergo changes during brain development and that the conformations of the channel structures interacting with lidocaine must be different in brain and muscle channels.

Animals↗
PubMed1998

The influence of reproductive stage on the selenium status of sheep in a low-selenium region.

The selenium status of sheep was evaluated during the reproductive stage in a region of low selenium level. Serum selenium concentration, whole blood glutathione peroxidase activity (GSH-Px), which is a good indicator of protection against oxidative damage, as well as the activities of creatine kinase (CK) and aspartate aminotransferase (AST), the plasma indicators of muscle damage, were evaluated in a group of ewes during gestation and lactation and in their lambs. The selenium requirements of ewes were found to increase during lactation. There were no differences in GSH-Px activity between the experimental and the control groups throughout the reproductive stage. In the second half of pregnancy GSH-Px activity was subnormal. In spite of this, no evidence of existing pathologic conditions associated with selenium deficiency was found, since the muscle markers CK and AST were within the normal range. In the same way, no distinct symptoms of nutritional myopathy were observed in the lambs, suggesting that the low selenium level found in the ewes did not cause alterations in their development.

Animals↗
PubMed1998

[Computed tomography of acute primary epiploic appendicitis].

Primary epiploic appendicitis is a rare but well known intraabdominal inflammatory process that characteristically presents with an onset of symptoms similar to diverticulitis, appendicitis and other abdominopelvic processes. CT findings are pathognomonic, consistent with a pericolonic oval shaped area of increased density with peritoneal thickening, and fat stranding. The condition is self limited and resolves completely within days under non-steroid antiinflammatory therapy.

Acute Disease↗
PubMed1997

Changes in sodium channel function during postnatal brain development reflect increases in the level of channel sialidation.

Developmental changes of forebrain sodium channels were studied at three postnatal ages: P0, P15 and adult (P30/P180). Electrophysiological analysis determined that the midpoint potential of activation was -64, -75 and -81 mV for P0, P15 and adult channels, respectively. At negative potentials, gating state changes were observed in all channels; at positive potentials they were observed in most P0 (72%) and to a lower extent in older channels (25%). A long non-conductive state was displayed with a higher frequency in P0 than in older channels. Immunoblot analysis determined that the apparent molecular weight was approximately 227, approximately 241 and approximately 246 kDa for P0, P15 and adult channels, respectively. Upon neuraminidase treatment, which cleaves sialic acids, these differences in molecular weight were abolished. The data suggest that these developmental changes in the function of forebrain sodium channels correlate with changes in the channel's sialidation level.

Animals↗
PubMed1997

Epidemiologic study of Guillain-Barré syndrome in children <15 years of age in Latin America.

In 1986, surveillance of acute flaccid paralysis (AFP) cases among children <15 years of age was implemented in Latin America as part of the initiative to eradicate poliomyelitis from the Western Hemisphere. Data on AFP, including Guillain-Barré syndrome (GBS), could be analyzed from a regional registry system and from specific GBS studies in seven countries. Between 1989 and 1991, 3112 cases of GBS were reported in Latin America, representing 52% of all nonpolio AFP cases. From the studies in seven countries, a total of 1527 GBS cases (49%) were studied, representing an overall annual incidence rate of 0.91/100,000 children <15 years old. Follow-up investigations showed a persistent muscular weakness at 60 days, 6 months, and 1 year after onset in 61%, 14%, and 10% of children, respectively. This study confirms that with the disappearance of polio, GBS arises as the most common cause of AFP.

Adolescent↗
PubMed1997

alpha-Methylnoradrenaline-induced contractions in rat aorta are mediated via alpha 1D-adrenoceptors.

The subtype(t) of alpha-adrenoceptor-mediating contractions to alpha-methynoradrenaline in the rat aorta has been investigated by using alpha-adrenoceptor-selective competitive antagonists and the alpha 1-adrenoceptor selective agonist, phenylephrine, for comparison. alpha-Methylnoradrenaline and phenylephrine elicited concentration-dependent contractions in the endothelium-denuded and endothelium-intact aortic rings with similar potencies and maximal effects. alpha-Methylnoradrenaline- and phenylephrine-induced contractions in endothelium-denuded aortic rings were competitively antagonized by prazosin (pA2 = 9.38 and 9.13; respectively) and rauwolscine (pA2 = 7.19 and 6.60, respectively). This confirms that there is an alpha 1- and a non alpha 2-adrenoceptor response to alpha-methylnoradrenaline in the rat aorta. The subtype selective alpha 1D-adrenoceptor antagonist, BMY 7378, was found to antagonize contractions to alpha-methylnoradrenaline and phenylephrine competitively in endothelium-denuded and endothelium-intact aortic rings. The pA2 values of BMY 7378 against alpha-methylnoradrenaline (8.39 and 8.41; endothelium-intact and endothelium-denuded, respectively) and phenylephrine (8.64 and 8.76; endothelium-intact and endothelium-denuded, respectively), are consistent with its published functional potency and clonal alpha 1D-adrenoceptor binding affinity. In addition, contractions to alpha-methylnoradrenaline and phenylephrine in endothelium-denuded aortic rings, were potently inhibited by WB 4101 with pA2 values of 9.75 and 9.25, respectively. The high pA2 values for WB 4101 indicate that the alpha 1B-adrenoceptor subtype does not seem to participate in alpha-methylnoradrenaline (and phenylephrine) induced contractions in this artery. These results suggest that the alpha 1D-subtype plays a determining role in rat aorta contractions induced by alpha-methylnoradrenaline.

Adrenergic alpha-Agonists↗
PubMed1997

Use of the Nottingham Health Profile for measuring health status of patients in methadone maintenance treatment.

This study was conducted to assess changes in health-related quality of life over a 3-year follow-up period in a cohort of 135 opioid dependent patients using the Nottingham Health Profile (NHP) questionnaires. Data obtained at 12 months from 80 patients retained in the programme are presented. In summary, opioid addicts in a methadone maintenance programme for a 12-month period experienced an early and substantial improvement in health-related quality of life. The use of the NHP questionnaire to monitor changes in the subjective health of opioid-dependent patients over time provides new insights in the assessment of treatment effectiveness of methadone maintenance programmes.

Adult↗
PubMed1997

Effects of thiopental on endothelium-dependent responses in rat aorta.

Effects of pretreatment with thiopental on endothelium-dependent vasodilator responses elicited by drugs in rat aortic rings were investigated. The vasodilators employed were acetylcholine and histamine (endothelium- and receptor-dependent), A23187 (endothelium-dependent but receptor-independent) and sodium nitroprusside (endothelium-independent); they were tested 15 or 60 min after aortic preparations were exposed during 15 min to thiopental. Pretreatment with the barbiturate reversibly inhibited relaxation elicited by either acetylcholine and histamine, but a high concentration of the anesthetic was needed (3.1 mg/ml). On the contrary, thiopental did not modify the relaxation elicited by sodium nitroprusside or A23187. In addition, the barbiturate inhibited basal and acetylcholine-stimulated production of nitrites (an indicator of nitric oxide output) in aortic rings. In conclusion, thiopental inhibited the endothelium-dependent relaxation elicited by either acetylcholine or histamine. Although the barbiturate also inhibited nitric oxide production, the reduction in the relaxant response provoked by it does not seem to be the result of direct guanylate cyclase or nitric oxide synthase alterations, since thiopental did not modify the effect of sodium nitroprusside or A23187. Disturbances elicited by thiopental on endothelial receptors or on signal transduction elements may indirectly provoke nitric oxide synthase inhibition.

Animals↗
PubMed1997

[Food patterns among adults visiting primary care clinics in the metropolitan region].

AIMS: To assess the intake of foods and nutrients in a group of adults of the Metropolitan Region of Chile and to identify food intake patterns which may need to be modified according to the guidelines of health promotion. METHODS: A non-randomly selected group of 859 adults (410 men) from 120 health care centers of the National Health System (October 1995) was studied. Food intake was assessed by 24-hour recall applied by well-trained standardized nutritionists. Both frequency and food and nutrients intake were calculated. RESULTS: The mean age was 35.8 +/- 10.6 years old. Median energy, protein and fat intake in male were 2324 kcal, 84 g y 70 g, respectively. For women, medians intake were: 1668 kcal, 59 g and 53 g respectively. From the total sample 72%, 53% y 71% reported consumption of less than two servings of milk product, vegetables and fruits. Likewise 42%, 36% y 22% of subjects had calcium, vitamin A and C intake below than 50% of the corresponding recommended dietary allowances (RDA). On the other hand 24% of the sample had daily salt consumption higher than 5 g, 37% had energy intake derived from fat higher than 30% of total calories and 15% had more than 10% of the energy supplied by sugar. CONCLUSIONS: A significant part of the adult population had inadequate patterns of food intake which confirms the need to promote a healthier diet.

Adult↗
PubMed1997

[Proposal of a new standard for the nutritional assessment of pregnant women].

BACKGROUND: There is evidence to suggest that the criteria for nutritional assessment of pregnant women, used by the Chilean Ministry of Health, overestimates nutritional disturbances. AIM: To propose a new reference table to assess the nutritional status of pregnant women, based on body mass index. MATERIAL AND METHODS: The table was theoretically defined using criteria for normality proposed by FAO and the weight increase during pregnancy that is associated with a lower maternal and fetal morbidity and mortality. In 665 pregnant women, weight, height, mid arm circumference and skinfolds were measured using standard techniques. Body mass index, arm fat and muscle area and percentage of body fat were calculated. Body composition for each nutritional category, derived from the body mass index or "Rosso-Mardones classification", was analyzed. RESULTS: According to the new table, under weight women had lower percentage of body fat and mid arm circumference and overweight women had higher weight, skinfold thickness and percentage of body fat than the homologous groups defined according to Rosso-Mardones tables. CONCLUSIONS: The proposed reference table may be useful to correct distortions generated by the current norms for nutritional assessment of pregnant women, proposed by the Chilean Ministry of Health. It has to be validated, analyzing its sensitivity, specificity and predictive value to predict fetal and maternal variables.

Adult↗