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Biomedical subjects

M Costales

Publications and source records attributed to M Costales.

18 recordsLinked to original sources
PubMed2004

Thirst changes in offspring of hyperreninemic rat dams.

The aim of this study was to investigate the changes in thirst dependence on the renin-angiotensin system (RAS), in offspring of hyperreninemic, hyperdipsic, and natriophilic rat dams. Female rats underwent a partial aortic ligature between the renal arteries (PAL) or were sham-operated (SHAM). At 6 days of age, offspring of PAL (O-PAL) and SHAM (O-SHAM) dams were injected with isoproterenol (subcutaneously, 500 microg/kg body weight) or vehicle. Pretreatment with captopril (intraperitoneally, 50 mg/kg) on isoproterenol-induced thirst was also studied. Plasma renin activity in dams and hematocrit and osmolality in pups were measured. O-PAL had a greater water intake than O-SHAM. However, they responded similarly to isoproterenol or isoproterenol with captopril pretreatment. Only minor differences in hematocrit and osmolality were found between O-SHAM and O-PAL rats after isoproterenol or vehicle treatment. Beta-adrenergic or angiotensinergic responsivity seems not to be altered in offspring of hyperrenimic, hyperdipsic, and natriophilic dams. Nevertheless, other thirst responses of offspring may be critically dependent upon uterine conditions.

Animals↗
PubMed2003

Quantitative histochemical assessment of oxidative metabolism in the subfornical organ after partial aortic ligature in rats.

Circumventricular organs are considered to be involved in hydromineral homeostatic responses. In this study we used quantitative histochemistry of cytochrome oxidase to evaluate the oxidative metabolic activity of the subfornical organ of rats with a partial aortic occlusion. These rats showed a significant increase in water intake from the second day after the ligature, while natriophilia was already significant on the first day. Greater levels of cytochrome oxidase activity were found in subfornical organs of partial aortic ligated rats when compared with control, providing further evidence for the involvement of this circumventricular structure in fluid homeostasis at least in this hyperdipsic, hypernatriophilic, hyperreninemic and hypertensive experimental model.

Animals↗
PubMed1998

Effect of castration and gonadal hormones on insulin-induced drinking.

Female Wistar rats in any of the estrual phases have been shown to drink significantly more water than males (p < 0.05), after a single I.P. insulin injection (5 U/kg b.wt.). Sexual differences in insulin-induced drinking persisted after castration when it was made in adult rats (4.6 +/- 1.2 ml/2 h, males = 8; vs. 13.0 +/- 3.1 ml/2 h, females = 8; p < 0.05). On the other hand, when animals were castrated before puberty or when newborn, sexual differences in insulin-induced drinking disappeared. Hence, insulin-induced drinking seems to be a sex-dependent phenomenon that differentiates just before or during puberty since it is abolished by castration prior to sexual maturation. Sex hormone administration in male and female rats castrated at different ages showed a variety of actions on insulin-induced drinking. A pattern emerged showing that androgenized (testosterone treated) rats drank usually less in response to insulin than estrogen-treated rats (independent of their genetic sex). According to the above results, we can conclude that insulin-induced drinking is a phenomenon sensible to gonadal hormones, both by conditioning the differentiation of some physiological structure or mechanisms that underlay drinking behavior in that paradigm and by a direct action on these or other related mechanisms.

Animals↗
PubMed1997

Poliomyelitis eradication and its impact on primary health care in the Philippines.

Since 1992, the Philippines has conducted four national immunization days (NIDs) for polio eradication. Surveillance for acute flaccid paralysis (AFP) began in 1992. Through good routine immunization, the incidence of paralytic polio had decreased to low levels in the Philippines even before the NIDs were initiated. With continuously improving AFP and virologic surveillance, wild poliovirus has not been isolated since May 1993. NIDs had a direct positive effect on child health through supplementary immunization with oral poliovirus vaccine, measles vaccine, and tetanus toxoid, as well as through the distribution of vitamin A. Following the successful NIDs, the government budget for vaccine purchases increased significantly. Also, the NID strategy was used as a model for several other priority prevention programs of the Department of Health. Through the development of AFP surveillance, polio eradication also helped to improve surveillance for other Expanded Programme on Immunization diseases.

Adolescent↗
PubMed1996

Increased salt preference in adult offspring raised by mother rats consuming excessive amounts of salt and water.

This study was designed to evaluate the effects of an early high-salt environment on the maternal and the young offspring physiology and on the adult offspring sodium appetite. Twenty-five-adult female Wistar rats were pseudorandomly divided into two groups. Twelve animals underwent a partial ligature of their abdominal aorta (PAL). Once polydipsia and sodium appetite (tested by measuring water and a 2.7% NaCl intakes) developed, they were mated. The other 13 rats (SHAM) were sham-operated and also mated. Throughout pregnancy and lactation, water and salt intake of PAL rats was consistently and significantly higher than that of the Sham. On gestation day 20, amniotic fluid and maternal plasma sodium concentration of PAL and Sham rats did not differ. Sodium concentration in the milk of the lactating PAL group was elevated (P < 0.05) on day 20 after delivery. At 0, 10 and 21 days of age, plasma sodium concentration of PAL offspring (PAL-O) and Sham offspring (Sh-O) were not significantly different. At 90 days of age, the salt preference of PAL-O rats was greater than that of Sh-O rats after 7 days of sodium deprivation (P < 0.01).

Aldosterone↗
PubMed1996

Changes of blood pressure responsiveness in rats exposed in utero and perinatally to a high-salt environment.

We tested the hypothesis that the pressor responses to angiotensin II could be influenced by an early salt exposure. Twenty-five adult female rats were pseudorandomly divided in two groups. Twelve animals underwent a partial ligature of their abdominal aorta (PAL). Once polydipsia and sodium appetite developed, these rats were mated. The other group (13 rats) was sham-operated (Sham) and mated. Throughout pregnancy and lactation, water and 2.7% NaCl solution intakes differed between the two groups of mother rats. PAL offspring (PAL-O; n = 14), and Sham-operated offspring (Sh-O; n = 10), were maintained on a solid diet containing 1% NaCl, tap water and a 2.7% NaCl solution. At 90 days of age, pressor responsiveness to intravenous angiotensin II (50, 100 and 200 ng) was assessed in anesthetized rats. The pressor responses to 50 and 200 ng angiotensin II were significantly greater in PAL-O rats than in Sh-O rats. These results support the hypothesis of a modulation of cardiovascular responsiveness or its underlying mechanisms by an early high salt environment.

Angiotensin II↗
PubMed1996

Factors influencing the return to work of patients after hip replacement and rehabilitation.

OBJECTIVE: To determine the incidence of medical and sociocultural factors on the return to work of patients after hip replacement and rehabilitation treatment. DESIGN: Case review. Frequency and association of variables' analysis. SETTING: The rehabilitation unit of a general hospital in Oviedo (Spain). This setting is a part of an institutional referral center and is the only state-owned hospital that provides rehabilitation treatment for hospitalized patients from a rural and urban area of about 1,000,000 inhabitants. PATIENTS: 747 patients of both sexes, all of them working before receiving treatment, age range 18 to 64 years. MAIN OUTCOME MEASURES: Relationship of several variables: age, sex, habitat, level of education, type of work, underlying illness, walking ability, pain, and type of social security versus return to work. RESULTS: At discharge, 25% of patients return to work. There is a significant association (p < .001) between return to work and any of the following variables: underlying illness, kind of work, walking ability, habitat, and educational level. CONCLUSION: This physiopathology of symptoms and signs of the patients is not the unique indicator of whether a person will continue working after hip replacement and rehabilitation treatment. Extramedical factors, such as social status, kind of work, and cultural background, are very influential.

Adolescent↗
PubMed1993

Transcranial oblique lateral radiography to verify the position of the mandibular condyles with the use of functional appliances.

By means of standardized transcranial oblique lateral (TOL) radiographs, the position of the mandibular condyles in the glenoid fossae of 14 patients with Class II division 1 malocclusion was studied at the beginning of treatment with or without functional appliances placed in position, and also at the end of treatment. A significant increase in the distance between the upper point of the condyle and the glenoid fossa was found when the appliance was worn for the first time. This displacement was found to disappear at the end of the treatment even when the appliance was placed in position.

Activator Appliances↗
PubMed1991

Attenuation of insulin-induced drinking by beta-adrenoceptor antagonists.

Insulin-induced drinking (IID) in male Wistar rats, evoked by administering 5 U/kg of crystalline porcine insulin i.p., was significantly decreased by propranolol (0.1 and 0.5 mg/kg s.c.) after 1 and 2 h. The blood glucose of rats treated with a much higher dose of propranolol (10 mg/kg body weight) and insulin did not differ from that of rats treated solely with insulin after 30 and 120 min. Atenolol (0.5 mg/kg s.c.) caused a reduction in IID after 1 and 2h. Butoxamine (1 mg/kg s.c.) also reduced IID after 1 and 2h, and at 0.5 mg/kg after 1h. The alpha-blocker, phenoxybenzamine (10 mg/kg s.c.), had the opposite effect, stimulating IID after 2h. There is no direct evidence that insulin activated the sympathetic system at the doses used in these experiments. Nevertheless, the results reported here seem to be compatible with the involvement of the sympathetic system in IID, possible through the renin-angiotensin system.

Animals↗
PubMed1991

Psychological aspects of insulin-induced thirst.

Fifteen normal volunteers received one insulin injection or saline in two nonconsecutive days. At 0', 30', 60' and 90' water intake was measured. Simultaneously subjective thirst and hunger were recorded by running a set of psychological tests. Water intake was higher after insulin than saline at 60' and 90'. Insulin increases thirst sensation even before the sensation of hunger.

Adult↗
PubMed1990

Insulin stimulation of water intake in humans.

Drinking response to the intravenous administration of insulin (0.1 U/kg) was studied in 15 volunteers (eight males and seven females). Water intake was significantly higher after insulin than after saline administration during the 90-min period studied. Plasma glucose decreased significantly in individuals receiving insulin and the time of the maximum decrease (30 min) was concurrent with the beginning of water intake. Haematocrit values in the insulin-treated group were also significantly higher at that time. Plasma renin activity (PRA) after insulin administration was higher than under basal conditions or after saline injection. On the other hand, psychological responses indicated that insulin probably elicits thirst prior to the hunger which appears with hypoglycaemia. A possible role of endogenous insulin in meal-related thirst is hypothesized.

Adult↗
PubMed1989

Effects of inhibitors of the renin-angiotensin system on water intake after insulin administration.

Male wistar rats drank in a dose-related manner, in response to 1 to 40 U/kg of i.p. insulin. Maximum intakes took place during the first 30 min after i.p. insulin administration, coinciding with the period of maximal drop of blood glucose. Plasma renin activity (PRA) in rats treated with i.p. insulin was higher than in basal conditions or after saline injection. Nephrectomy and adrenalectomy did not abolish insulin-induced drinking. A low dose of captopril (0.1 mg/kg s.c.) did not modify insulin-induced drinking, but a higher dose (10 mg/kg s.c.), or enalapril (0.5 mg/microgram s.c.), significantly increased insulin-induced drinking. Enhancement of insulin-induced drinking by s.c. captopril was not secondary to an increased diuresis. Captopril (50 micrograms i.c.v.) significantly reduced the cumulative water intake after i.p. insulin (20 U/kg i.p.) plus s.c. captopril (10 mg/kg). The blockade of central receptors for angiotensin II with sarile-AII (5 micrograms) significantly diminished insulin-induced drinking. It appears that the peripheral renin angiotensin system is not necessary for insulin-induced drinking but central angiotensin II plays an important role.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1989

Effect of insulin administration on water drinking in children.

The effect of insulin administration on water intake, was studied in children submitted to standard protocols for stimulation of secretion of hypophyseal hormones by i.v. treatment with several different drugs: insulin, insulin plus TRH and LH-RH; and propranolol, clonidine or LH-RH. Drinking was measured from 0 to 90 min after drug administration; from blood samples taken at 60 min for hypophyseal hormones analysis, microhaematocrit values were measured, as well as plasma renin activity (PRA) and glycaemia. Water intake was significantly higher in both groups of patients receiving insulin than in the control group (no insulin). Haematocrit values did not change after 60 min. There was a significant correlation of glycaemia of individuals from all three groups and water intake at 60 min. PRA was significantly higher in insulin treated individuals.

Adolescent↗
PubMed1984

Increased sodium appetite and polydipsia induced by partial aortic occlusion in the rat.

Partly occluding the abdominal aorta between the renal arteries caused the rat to drink steadily increasing amounts of 2.7% NaCl when this solution and water were available. The increase in NaCl intake preceded the increase in water intake that also occurred after aortic occlusion, and intakes of both fluids were reaching maximal values 1-2 weeks after operation. The amounts of fluid drunk during the day increased greatly. This change in the pattern of drinking, together with the rise in fluid intake and the drop in food intake meant that drinking was less associated with feeding than it is in the normal rat. The rats went into fluid and electrolyte deficit within 24 h of partial aortic occlusion and remained in deficit for about a week (the duration of the balance experiment) despite increasing intakes of NaCl and water. Renal function was unimpaired during the first 2 weeks, and the abnormal signs were mainly and rapidly reversed by removal of the ischaemic kidney or administration of the angiotensin converting enzyme inhibitor, captopril. Therefore polydipsia and increased sodium appetite in the first 2 weeks after aortic occlusion were likely to have been caused by fluid deficit, with increased renin secretion from the ischaemic kidney contributing to both behaviours. Arterial blood pressure rose immediately after aortic occlusion, before the onset of increased drinking. Up to 3 weeks after operation the incidence and severity of the hypertension did not appear to depend on the spontaneous changes in intake of water or hypertonic NaCl.

Animals↗
PubMed1978

Sex difference in polyethylenglycol-induced thirst.

The polyethylenglycol-induced thirst in male and female castrated rats has been studied. The polyethylenglycol (PG) increases the water intake more in females than in males. Estradiol benzoate and testosterone P. diminishes the amount of water drunk after PG treatment in the females, but not in the males.

Animals↗
PubMed1978

Angiotensin-induced drinking: sexual differences.

The dipsogenic effect of Angiotensin-II (A-II) in relation to sexual variables was studied. It was found that Angiotensin-II administered SC constitutes a stimulus which induces more drinking in females than in males. Moreover, the adult females show maximum sensitivity to A-II during proestrus. The males and females castrated at birth, and females androgenized at birth, drink similar volumes of water after A-II SC injection. The pattern of stimulated intake is different in the two sexes, and appears to depend upon the development of the rats.

Angiotensin II↗
PubMedDate not supplied

[Renal effects of prolonged sevoflurane anesthesia in Wistar rats].

OBJECTIVES: To assess renal safety of sevoflurane administered to Wistar rats at clinical concentrations during prolonged periods of inhalation. MATERIAL AND METHODS: The experimental animals were assigned to two groups of six rats each. Group I received anesthesia with 1.5% sevoflurane for 6 hours and group II received the same concentration of sevoflurane for 15 hours. The anesthesia was inhaled in an open circuit of fresh air at 1 l/min (medicinal air, 22.75% O2). The animals were kept in metabolic cages throughout the nine days the experiment lasted. Weight and urine output were recorded daily and the day before anesthesia was started, inorganic fluoride and blood was analyzed for renal function (urea, sodium, and blood urea nitrogen [BUN]). Between two and three hours after withdrawal of anesthesia, inorganic fluoride was again assessed, and on the last day of the experiment a new blood sample was taken to evaluate renal function. Kidney tissue was then studied. RESULTS: The two groups were similar as to weight, urea, sodium and BUN. Hourly diuresis was significantly greater after anesthesia in group II but not in group I. Inorganic fluoride was significantly higher in both groups, with postanesthetic levels of 22.42 +/- 1.76 microM/l in group I and 35.05 +/- 1.80 microM/l in group II. Renal tissue from both groups appeared normal under an optical microscope. CONCLUSIONS: Sevoflurane at the doses tested increases inorganic fluoride concentrations although for both periods the levels stayed under 50 microM/l, which has been considered the nephrotoxic threshold. No signs of changes in renal function were observed in blood texts or tissue studies.

Anesthetics, Inhalation↗