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Biomedical subjects

J Zicha

Publications and source records attributed to J Zicha.

At least 109 records · Page 6Linked to original sources
PubMed1989

Bopindolol in the treatment of hypertension: a double blind study comparing bopindolol and metoprolol.

The article presents the experience gained with a new betablocker- bopindolol-in the treatment of hypertension. Using a three-month double blind study conducted in 2 centres, the antihypertensive effect of bopindolol and metoprolol was compared in a total of 86 patients. The incidence of undesirable effects was determined, and biochemical parameters before and after therapy were followed up. Both drugs were equally effective in controlling blood pressure. In 70% of patients with mild and moderate hypertension, diastolic pressure values less than 95 mmHg were obtained in monotherapy with a betablocker. The incidence of undesirable effects was low, the drug was tolerated well. Biochemical parameters did not change within the three months of study.

Adrenergic beta-Antagonists↗
PubMed1989

An analysis of spontaneous hypertension in spontaneously hypertensive rats by means of new recombinant inbred strains.

The mode of blood pressure inheritance and some genetic markers of spontaneous hypertension were evaluated in a new set of recombinant inbred (RI) strains obtained by crossing of normotensive (BN.lx) and hypertensive (SHR) progenitor strains. Blood pressure values of RI strains were continuously distributed between both progenitor strains, although normotensive strains slightly prevailed. Statistical analysis suggested that there are three major genes and multiple minor genes responsible of the determination of spontaneous hypertension. The association between blood pressure and gene(s) within RT1 complex or gene(s) closely linked to it was found by RI strain analysis. This suggestion was confirmed by the detection of significant difference in blood pressure between SHR and SHR.1N congenic strains. Our results indicate that RT1 complex gene(s) may be involved in the development of high blood pressure.

Animals↗
PubMed1989

[Diltiazem VUFB (Diacordin Spofa) in the treatment of arterial hypertension].

In an eight-week open clinical investigation controlled by placebo in 21 hypertonic patients the author tested the calcium ion antagonist produced in Czechoslovakia, Diltiazem, VUFB. Its very favourable antihypertensive action was proved in patients with arterial hypertension stage I and II (according to WHO), using a maximal daily dose of 180 mg without the need of combination with other antihypertensive drugs, incl. diuretics. The undesirable effects were mostly weak and developed during the first 12 days of administration of the drug. Then they disappeared. Only two patients discontinued treatment on account of severe subjective complaints. In the latter patients, however, lack of confidence into the new drug played a major role.

Diltiazem↗
PubMed1989

[The present level of control of hypertension in the South Moravian Region].

The authors present the results of a cross sectional and prospective investigation of hypertension in the South Moravian region. The inadequate control of high blood pressure is according to the authors due to inadequate screening, unsuitable dosage and selection of antihypertensive drugs, lack of confidence in medicamentous treatment, inadequate cooperation of doctors and patients, and frequently lack of perception of the disease. The authors mention also the importance of the unbalanced supplies in previous years. They refute objections that screening and treatment of hypertension is time consuming and expensive and consider prevention the prerequisite of all efforts to reduce the morbidity and mortality from cardiovascular diseases.

Adult↗
PubMed1988

Effects of dietary calcium on the development of salt hypertension in young and adult Dahl rats.

The effect of dietary calcium on the development of salt hypertension was studied in young and adult Dahl rats. Age-dependent development of blood pressure was compared in salt-sensitive (DS) and salt-resistant (DR) Dahl rats that were fed either a low-calcium (0.15%) or a high-calcium (2.5%) diet. Systolic blood pressure was consistently higher in DS rats than in a comparable group of DR rats. In young DS rats the high-calcium diet transiently attenuated the development of hypertension, whereas in adult rats this diet potentiated the development of hypertension. In young DS rats total plasma calcium was increased by the high-calcium diet, but in adult rats it was significantly decreased. Our results suggest that the effects of dietary calcium supplementation on calcium metabolism and the development of salt hypertension in DS rats depend on the age at which calcium supplementation is started.

Age Factors↗
PubMed1988

Sympathetic innervation of blood vessels in rats with aortic constriction hypertension.

The adrenergic innervation of blood vessel wall was studied in various vascular beds of adult rats with experimental hypertension induced by the constriction of the aorta between the origins of both renal arteries. A moderate expansion of body fluids was demonstrated in this hypertensive model. The decrease of the density of adrenergic plexus in the vessel wall as well as the diminished catecholamine fluorescence were found only in renal vessels. These changes were pronounced in the left renal artery and vein even if the left kidney was not subjected to elevated blood pressure. Thus the alteration of vascular adrenergic innervation in hypertensive rats is not a consequence of high blood pressure but it seems to be a part of neurohumoral pathogenetic mechanisms.

Animals↗
PubMed1988

Kinetics of regional blood-brain barrier transport of L-leucine in Brattleboro rats.

The transport of L-leucine across the blood-brain barrier was studied in heterozygous (NON-DI) and homozygous (DI) Brattleboro male rats using the carotid bolus injection technique. Furthermore, general hemodynamic parameters and cerebral blood flow were measured. No significant hemodynamic differences were found between DI and NON-DI rats except for a 22% lower cerebral blood flow in the olfactory bulb of DI rats. The maximum velocity of L-leucine transport (Vmax), the half saturation constant (Km) and the nonsaturable transport constant (KD) were estimated in nine brain regions. The Vmax values of NON-DI rats were by 28% to 64% lower than those of DI rats. The calculated regional Km values of NON-Di rats were by 14% to 58% lower. These differences were most pronounced in hippocampus and hypothalamus. The results support the suggestion that endogenous vasopressin may alter the large neutral amino acid transport across the blood-brain barrier.

Animals↗
PubMed1987

Sympathetic nervous system and age-dependent salt hypertension in Brattleboro rats.

The effects of early sympathectomy on the development of salt hypertension were studied in prepubertal and adult rats with hereditary diabetes insipidus (DI). Early guanethidine administration caused a pronounced and long-term destruction of sympathetic nervous system (SNS) in Brattleboro rats in which blood pressure (BP) was significantly decreased until the age of 22 weeks. This SNS impairment did not abolish the age-dependent BP response of salt-loaded rats that was still greater in young than in adult sympathectomized DI rats. BP of young uninephrectomized DI rats was higher in the late than in the early phase of salt hypertension development. The early sympathectomy lowered BP and increased mortality in all groups of saline drinking DI rats except young uninephrectomized animals in which hypertensive response was attenuated but not prevented. It could be suggested that 1) increased BP response of young rats to high salt intake occurs even in animals with attenuated principal pressor systems, 2) the effects of early sympathectomy on the development of salt hypertension depend on the actual hemodynamic pattern, and 3) moderate BP increase might be a part of homeostatic mechanisms defending the organism threatened by chronic salt overload.

Aging↗
PubMed1987

Sodium pump activity in young and adult salt hypertensive Dahl rats.

The possible role of endogenous sodium pump inhibitors was studied in salt-sensitive rats of Dahl strain which were influenced by high salt intake either in youth (from prepuberty) or only in adulthood. The aim of our study was to search for the relations between the age-dependent blood pressure response to high salt intake and the changes in volume or distribution of body fluids, red cell ion transport or Na+,K+-ATPase activity in various tissues of salt-sensitive (S/JR) and salt-resistant (R/JR) rats. Salt hypertension was especially pronounced in those S/JR rats which were maintained on a high-salt diet from prepuberty. This was accompanied by the moderate expansion of body fluids in young but not in adult hypertensive animals. Na+,K+-ATPase activity was suppressed in both kidney and heart of young S/JR rats with salt hypertension while this was not true in adult hypertensive animals. On the other hand, no inhibition of sodium pump was observed in brain microsomes and erythrocytes of severely hypertensive young S/JR rats. Moreover, no increased levels of endogenous sodium pump inhibitors were detected in plasma of salt hypertensive S/JR rats. Thus our study indicated the age-dependent suppression of sodium pump activity in some tissues of salt hypertensive Dahl rats but we failed to confirm increased levels of circulating sodium pump inhibitors in young salt hypertensive rats.

Aging↗
PubMed1987

Age-dependent DOCA-salt hypertension in Brattleboro rats: the role of vasopressin.

The age-dependent participation of endogenous vasopressin (VP) during the development of DOCA-salt hypertension was studied in young (28-day-old) and adult (75-day-old) Brattleboro rats. VP-deficient homozygous (DI) rats were compared to heterozygous (non-DI) littermates which do synthetize VP. Six weeks of DOCA-salt treatment did not increase blood pressure (BP) in adult DI rats. On the other hand, in young DI animals there was a significant rise of systolic and mean arterial pressure accompanied by the hypertrophy of the left ventricle. This moderate DOCA-salt hypertension of young DI rats contrasted with severe hypertension of young non-DI rats. Increased BP response of young VP-deficient DOCA-salt treated rats was independent of the saline intake or blood volume expansion which were similar in young hypertensive and adult normotensive DI animals. It could be concluded that vasopressin is not essential for the induction of DOCA-salt hypertension in young rats even if VP is responsible for the magnitude of BP elevation. In contrast to young animals vasopressin is very important for the development of DOCA-salt hypertension in adult rats.

Aging↗
PubMed1987

Haemodynamics and the participation of pressor systems in young and adult rats with age-dependent DOCA-salt hypertension.

Increased systemic resistance is the main haemodynamic abnormality in DOCA-salt hypertension which is more pronounced in young than in adult rats. A mild increase of cardiac output also contributes to higher blood pressure in young animals. Arterial compliance is decreased only in young hypertensive rats. The acute blockade of different pressor systems indicates that the role of back-up pressor systems (vasopressin and angiotensin II) is increased in adult DOCA-salt hypertensive animals while the increased activity of adrenergic system and digoxin-like factors contributes to the enhanced hypertensive response of young rats.

Aging↗
PubMed1986

Endogenous vasopressin and the weaning period in Brattleboro rats.

Vasopressin, which is important for behavior and brain development, begins to influence osmoregulation with the onset of weaning. We studied the role of vasopressin in the development of feeding behavior since its mechanisms might be essential for the age determination of the suckling and weaning periods. Radionuclide methods were employed to follow maternal milk, solid food and water consumption in developing Brattleboro rats. The appearance of solid food intake and the spontaneous extinction of maternal milk intake indicated the onset and the end of weaning. The absence of endogenous vasopressin did not influence the onset and/or the duration of the weaning period. Both vasopressin-deficient homozygous Brattleboro rats and their heterozygous littermates (with preserved vasopressin synthesis) began to consume solid food and water at the age of 16 days and their intake of maternal milk was terminated about the 27th day of age. Thus, the maturation of feeding behavior in the suckling and weaning periods is vasopressin-independent.

Animals↗
PubMed1986

Age-dependent blood pressure response to increased salt intake in rats influenced by a transient renal ischaemia.

The influence of renal dysfunction (induced by ischaemic injury) on the development of salt hypertension was studied in rats which were exposed to 60 min of renal ischaemia when either immature or adult. Saline-drinking age-matched animals served as controls. The blood pressure, plasma urea concentration, extracellular fluid volume (ECFV) and renal mass were measured 21 and 50 days after renal ischaemia. Increments of plasma urea concentration and ECFV were considered to be indicators of renal dysfunction. Increased renal mass was used as an estimate of the degree of renal injury. In adult rats, both plasma urea concentration and ECFV were increased 3 weeks after renal ischaemia. This correlated with a pronounced increase of renal mass. A similar relation of renal mass to ECFV was still present 50 days after renal ischaemia. In rats treated when immature the increment of plasma urea concentration was much smaller and ECFV did not differ significantly from the control volumes. A mild salt hypertension developed only in those rats which were treated when immature. On the other hand, the blood pressure tended to decrease in animals treated when adult. It is concluded that mild renal dysfunction facilitates the development of salt hypertension in immature rats. This is in contrast with the reversed effects of extensive renal dysfunction in adult animals. It is suggested that the age of animals is more important for the induction of salt hypertension than the degree of renal dysfunction.

Age Factors↗
PubMed1986

Experimental hypertension in young and adult animals.

The susceptibility of immature and adult animals to various environmental factors often differs because the response of the young organism can only involve those regulatory mechanisms that are available at the particular stage of development. Increased sensitivity to certain (e.g., hypertensive) stimuli may be limited to a relatively short age period that is usually characterized by the maturation of some important physiological functions. High salt intake seems to influence the animals especially during the weaning period and prepuberty, in the course of which profound developmental changes of circulation, electrolyte metabolism, and neurohumoral regulation have been demonstrated. Indeed, salt-dependent forms of experimental hypertension are more severe when they are induced in immature animals. Moreover, substantial differences in hemodynamics, distribution of body fluids, and involvement of pressor and natriuretic agents indicate that the mechanisms of salt hypertension need not be the same in immature and adult animals. For this reason, increased attention should be paid to developmental factors in the study of induced forms of experimental hypertension.

Age Factors↗