Biomedical subjects

E Stupnicka

Publications and source records attributed to E Stupnicka.

14 recordsLinked to original sources

PubMed1997

Physiological characteristics and hormonal profile of young normotensive men with exaggerated blood pressure response to exercise.

Exaggerated blood pressure (BP) response to exercise in normotensive subjects is considered as a predictor of future hypertension. The aim of the study was to find out whether elevated BP response to exercise is associated with any other haemodynamic, metabolic or hormonal abnormalities. Abnormal BP response to exercise, i.e. systolic BP (SBP) > 200 mmHg at 150 W or lower workload, was found in 37 out of 180 normotensive, male students, aged 20-24 years. Fifteen students with elevated exercise BP (group E) volunteered for further examinations. Their resting and ambulatory BP showed high normal values. Eight of them had a family history of hypertension. Four subjects met the criteria of cardiac hypertrophy. Significant correlations were found between exercise SBP and left ventricular mass index, average 24 h and daytime SBP recordings. In comparison with normal subjects of the same age (group N, n = 13), those from group E did not differ in body mass index, plasma lipid profile, fasting glucose, insulin and catecholamine (CA) concentrations, but had increased erythrocyte sodium content, slightly elevated plasma renin activity and cortisol level. During exercise, E subjects showed greater cardiac output (CO) increases with normal heart rate, total peripheral resistance (TPR) and plasma CA. There were no significant differences between groups in haemodynamic and plasma CA responses to posture change from supine to standing. Glucose ingestion (75 g) caused smaller increases in CO and smaller decreases in TPR in E than in N subjects without differences in BP, blood glucose plasma insulin and CA. It is concluded that young normotensive men with exaggerated BP response to exercise show some other characteristics that may be considered as markers of predisposition to hypertension or factors promoting the development of hypertension.

Adult↗

PubMed1994

Incidence of type I diabetes in people under 30 years of age in Barbados, West Indies, 1982-1991.

OBJECTIVE: To determine the incidence of type I diabetes among individuals < 30 years of age on the island of Barbados in the Caribbean. The population is predominantly African in origin but exhibits a relatively westernized lifestyle. RESEARCH DESIGN AND METHODS: Cases occurring during the years 1982-1991 were drawn from records at Queen Elizabeth Hospital and from physicians treating insulin-dependent diabetes mellitus (IDDM) patients. Patients using insulin and < 30 years of age at onset were included. Ascertainment was estimated at 94%. RESULTS: The average annual incidence of type I diabetes among Barbadians was 4.1/100,000 when age-adjusted to the world's population. There were 59 incident cases during this 10-year interval. The risk for males was 4.4 and for females 4.0/100,000. Among those 0-14 years of age, the risk was 5.0/100,000. Mean age at onset (+/- SD) was 14.7 +/- 6.9 for males and 12.5 +/- 5.7 for females. Males showed marked seasonal variation in risk and a more than threefold increase in annual incidence during 1984-1985. In contrast, females exhibited a stable pattern of IDDM risk during the 10-year interval. CONCLUSIONS: The incidence rate in Barbados falls near the lower limits of rates reported for Caribbean populations. There was a marked seasonal effect among males, even though the climate varies little throughout the year. This observation, and the incidence peak during 1984-1985, provide support for the role of environmental factors in the etiology of IDDM.

Adolescent↗

PubMed1992

Metabolic, body temperature and hormonal responses to repeated periods of prolonged cycle-ergometer exercise in men.

This study was designed to find out whether rest intervals and prevention of dehydration during prolonged exercise inhibit a drift in metabolic rate, body temperature and hormonal response typically occurring during continuous work. For this purpose in ten healthy men the heart rate (fc), rectal temperature (Tre), oxygen uptake (VO2), as well as blood metabolite and some hormone concentrations were measured during 2-h exercise at approximately 50% maximal oxygen uptake split into four equal parts by 30-min rest intervals during which body water losses were replaced. During each 30-min exercise period there was a rapid change in Tre and fc superimposed on which, these values increased progressively in consecutive exercise periods (slow drift). The VO2 showed similar changes but there were no significant differences in the respiratory exchange ratio, pulmonary ventilation, mechanical efficiency and plasma osmolality between successive periods of exercise. Blood glucose, insulin and C-peptide concentrations decreased in consecutive exercise periods, whereas plasma free fatty acid, glycerol, catecholamine, growth hormone and glucagon concentrations increased. Blood lactate concentrations did not show any regular drift and the plasma cortisol concentration decreased during the first two exercise periods and then increased. In conclusion, in spite of the relatively long rest intervals between the periods of prolonged exercise and the prevention of dehydration several physiological and hormonal variables showed a distinct drift with time. It is suggested that the slow drift in metabolic rate could have been attributable in the main to the increased concentrations of heat liberating hormones.

Adult↗

PubMed1990

Suppressive effect of beta-endorphin and naloxone on the secretion of cortisol under stress conditions in sheep.

The effect of an infusion of beta-endorphin and naloxone into the 3rd cerebral ventricle on the blood serum concentration of cortisol in non-stressed and stressed anoestrous sheep was studied. The infusion of naloxone alone did not alter the secretion of cortisol in non-stressed animals but the response to footshock was inhibited in that the cortisol values were significantly lower (P less than 0.05) when compared with those during the infusion of saline and footshocking. This opiate antagonist also suppressed the cortisol response to an infusion of beta-endorphin (P less than 0.001 and P less than 0.05). When the sheep infused with beta-endorphin were additionally exposed to footshock there was less enhancement of the secretion of cortisol (P less than 0.001 and P less than 0.05). The depressive action of beta-endorphin upon cortisol secretion in stressed sheep is matched by corresponding observations on man and it seems that endogenous opioids may inhibit or attenuate some hormonal responses to stress.

Animals↗

PubMed1989

Cardiovascular and sympatho-adrenal responses to static handgrip performed with one and two hands.

12 healthy men aged 21-25 years performed, in the sitting position, a sustained handgrip at 25% of their maximum voluntary contraction, first with each hand separately and then with both hands simultaneously. Heart rate (HR), systolic blood pressure (SBP), stroke volume (determined reographically) and plasma catecholamine concentration were measured during each handgrip test. The HR and SBP increased consistently during each handgrip test while stroke volume decreased by approximately 20% of the initial value. Cardiac output did not change significantly. There were no significant differences in the magnitude and dynamics of the cardiovascular responses between the tests with one and with both hands. Plasma noradrenaline and adrenaline levels showed similar elevations in response to handgrip performed with the right hand and with both hands, while during the exercise performed with the left hand the increase in the plasma catecholamine concentration was less pronounced. It was concluded that: (1) during sustained handgrip, performed in the sitting position by young healthy subjects, the stroke volume markedly decreases and cardiac output does not change significantly in spite of the increased HR; (2) the cardiovascular and sympatho-adrenal responses to static handgrip do not depend on the mass of contracting muscle when the same relative tension is developed.

Adult↗

PubMed1985

Changes in circadian rhythm and suppression of the plasma cortisol level after prolonged stress in the sheep.

Diurnal variations in the plasma cortisol level were studied in anoestrous, pro-oestrous and pregnant ewes subjected to weak electric stimulation of the fore-limbs 9 h daily for 3 consecutive days. In non-pregnant ewes the cortisol level rose on each of the 3 days when the stimulation was applied and then decreased on the day following the stimulation. A similar decrease in plasma cortisol concentrations in pregnant ewes appeared on the second day of footshocking. The acrophase of the circadian rhythm on electrostimulation days was synchronous with the time of application of footshocks; therefore, in stimulated ewes it was significantly accelerated compared to the prestimulatory day. A decrease in the plasma cortisol level in pro-oestrous and pregnant ewes was accompanied by disappearance of its normal rhythmicity. Since a normal plasma cortisol response to exogenous corticotrophin was noted after 3 days of footshocking it seems unlikely that the decrease in the cortisol level after prolonged stress was caused by exhaustion of the adrenal cortex. Some central mechanisms which could account for the biphasic changes in the plasma cortisol level and for disturbances of the hormone diurnal rhythmicity under conditions of prolonged stress are discussed.

Animals↗

PubMed1985

The effect of 6-hydroxydopamine infused into the third cerebral ventricle on the plasma cortisol concentration in sheep subjected to repeated and prolonged stress stimuli.

It has previously been observed that sheep subjected to repeated and prolonged stress stimuli showed biphasic cortisol responses. On the first and second day of stimulation an elevation was observed, while on the subsequent days and on the day after the stimulation a marked suppression of plasma cortisol level and a disappearance of its circadian rhythm was noted. It was hypothesized that these changes in the secretion of the hormone were caused by the alteration of catecholaminergic systems in the CNS. To verify this suggestion chemical lesions of the catecholergic systems of the diencephalon were carried out by the infusion of 6-hydroxydopamine (6-OHDA) into the third cerebral ventricle and animals treated in this fashion were subjected to repeated and prolonged electrical mild footshocking (applied during 3 days). The pretreated animals lost the circadian rhythm in cortisol secretion on the days before as well as during and after the electrical stimulation. The animals pretreated with 6-OHDA showed a significant rise of the plasma cortisol level during stimulation. This rise, as the highest daily concentration, occurring within about 1 h after the beginning of footshocking, was significantly accelerated in time with respect to the physiological acrophase, occurring in the early morning hours at the end of prestimulatory days. On the other hand, the pretreated animals did not show the decrease of plasma cortisol levels on the day after the stimulation, observed in normal non-pretreated ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1977