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Biomedical subjects

E Perez

Publications and source records attributed to E Perez.

At least 127 records · Page 7Linked to original sources
PubMed1980

Quantitative analysis of short term deprivation and recovery of desynchronized sleep in cats.

A quantitative analysis of desynchronized sleep (DS) deprivation (exposure to low ambient temperature) and recovery was carried out in unrestrained cats. The results show that: (1) the circadian obligate quota of DS is precisely regulated by a control mechanism paying by the 24th h the DS debt induced by up to 14 h of total DS deprivation, if recovery occurs during the rest phase of circadian photoperiodicity (CP); (2) during static rebound DS hourly duration is increased by 40 +/- 4 sec/h of total deprivation (mean and S.E.) and there is a statistically significant increase in the hourly frequency and in the duration of DS episodes, with respect to control values; (3) the hourly obligate and facultative quotas of DS amount to 409 +/- 82 and 229 +/- 140 sec/h (mean and S.D.), respectively. (4) preoptic heating during deprivation at low ambient temperature decreases the DS static rebound during recovery at control ambient temperature by an amount corresponding to the cumulative duration of DS episodes elicited by the preoptic treatment; (5) preoptic temperature decreases the more markedly the shorter the duration of exposure to low ambient temperature and regains control values the sooner the smaller the DS debt incurred during deprivation; (6) DS debt cumulation is a continuous process which develops at a steady rate during day and night, whereas DS debt payment is a discontinuous process (ultradian rhythm of DS) which develops at a variable rate depending on the DS debt and on the phase of CP.

Animals↗
PubMed1979

Additive effects of hypothermia and phenobarbitol upon cerebral oxygen consumption in the rat.

The quantitative effects of a combination of hypothermia and phenobarbital on cerebral oxygen uptake (CMRo2) was studied in rats, curarized and artificially ventilated with 70% nitrous oxide in oxygen. Cerebral blood flow (CBF) was measured with a modification of the KETY & SCHMIDT (1948) technique, using 133xenon as a tracer. Arteriovenous difference in oxygen content over the brain was measured and CMRo2 was calculated. Four groups were studied. Group 1 was a control group. The three experimental groups were injected with phenobarbital intraperitoneally: Group 2 with 50 mg/kg body weight; Group 3 with 150 mg/kg; and Group 4 with 50 mg/kg of phenobarbital, and, in addition, body temperature was lowered to 32 degrees C in this group. CMRo2 in groups 2, 3 and 4 was reduced by 22, 37 and 43%, respectively, compared to Group 1. The changes in CBF were of the same magnitude. In a previous study we have found that CMRo2 decreases by 5% per 1 degree C decrease in body temperature. The value for CMRo2 in Group 4 is close to the value obtained if the effect of 50 mg/kg body weight of phenobarbital on CMRo2 is added to the effect of a temperature reduction of 5 degrees C. It is concluded that the effects of barbiturates and hypothermia on CMRo2 are additive.

Animals↗
PubMed1977

Contraceptive method continuation according to type of provider.

A study was undertaken at the main PROFAMILIA clinic in Bogota, Colombia to compare the effectiveness of nurses and physicians in the delivery of family planning services. Contraceptive method continuation was the major outcome variable in this analysis. Clients were randomly assigned to physicians or nurses on their first visit and for the duration of care. On all revisits, data were collected pertaining to method prescribed, side effects, pregnancy, and method changes. There was a field survey at eight months to locate clinic drop-outs and determine their contraceptive use status. There were no significant differences in method continuation between clients who received services from physicians and those who received services from nurses. At nine months, the overall continuation of the first method prescribed was 79.1 per cent in the physicians' group and 75.8 per cent in the nurses' group (t = 1.057, p greater than .20). When controlling for first method used, the IUD users in the physicians' group had a continuation rate of 86.1 per cent and in the nurses' group 84.0 per cent (t = 0.556, p greater than .50). Of the pill users who received services from physicians, 78.1 per cent were continuing at nine months and 74.3 per cent of the pill clients in the nurses' group were continuing at nine months (t = 0.573, p greater than .50). There were no differences in pregnancy rates, side effects rates, and method change rates between the two groups. It may be concluded that these nurses were as effective as physicians in the delivery of family planning services.

Adult↗
PubMedDate not supplied

Effect of ethanol on human placental transport and metabolism of adenosine.

It has been suggested that adenosine is involved in the acute effects of ethanol in a number of tissues. The present study was undertaken to evaluate the role of adenosine on the vascular responses of perfused isolated human placental cotyledons after the acute administration of ethanol. The possibility that ethanol may effect the uptake and metabolism adenosine was also investigated. Uptake of adenosine was studied using the single-circulation paired-tracer dilution technique. Both adenosine and ethanol caused a dose-related increase in perfusion pressure of placental lobules. Pharmacologically relevant concentrations of ethanol (10-65 mM) significantly inhibited the uptake of [3H]adenosine between 25 and 50 per cent. Thin-layer chromatographic analysis of the perfusate after the administration of ethanol showed in a 17.9 +/- 0.6 per cent reduction of [3H]adenosine metabolism. These findings support the working hypothesis that placental adenosine, at least partially, mediates the placental disturbance elicited by the administration of acute ethanol, which may contribute to the pathogenesis of fetal alcohol syndrome.

Adenosine↗