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Biomedical subjects

J Zicha

Publications and source records attributed to J Zicha.

At least 127 records · Page 7Linked to original sources
PubMed1986

The adrenergic innervation of arteries and veins in rats with DOCA-NaCl hypertension: the role of sodium and chloride overload.

The adrenergic innervation of major arteries and veins was examined in DOCA-NaCl hypertensive rats using a histochemical fluorescent technique to detect the intraneuronal catecholamine content. The possible role of sodium and chloride ions was studied in DOCA-treated rats which were fed a low-salt diet which was supplemented with sodium bicarbonate instead of sodium chloride. Focal defects of adrenergic innervation were observed in blood vessels of DOCA-NaCl hypertensive rats. Nevertheless, the degree of these changes differed according to the vascular bed examined. A maximum decrease of the catecholamine content in varicosities of adrenergic terminals was found in the femoral vessels while there were nearly no changes in tail arteries and veins. Adrenergic innervation was usually more impaired in veins than in corresponding arteries of hypertensive animals. Pronounced changes in blood vessels of rats with DOCA-NaCl hypertension contrasted with the maximum alterations observed in those hypertensive DOCA-treated animals which were fed a NaHCO3-supplemented diet. Thus a chloride overload seems to be more important for alteration of adrenergic innervation than the degree of blood pressure elevation or the sodium overload per se.

Animals↗
PubMed1986

The importance of sodium and chloride ions for the development of DOCA-NaCl hypertension: a haemodynamic study.

The role of sodium and its accompanying anion for the development of DOCA-salt hypertension was studied in uninephrectomized DOCA-treated weanling Wistar rats which were fed a diet containing either sodium chloride or sodium bicarbonate (170 mmol/kg). The blood pressure was increased in both groups of rats with sodium overload as compared to rats fed a low-salt diet only. A decreased cardiac output and substantially elevated systemic resistance were demonstrated in both groups of rats with high sodium intake in comparison with rats kept on a low-salt diet. However, these haemodynamic changes were more pronounced in rats with sodium chloride overload than in animals with a high sodium bicarbonate intake. On the other hand, the rigidity of major arteries which was estimated as the pulse pressure/stroke volume ratio, was increased only in rats fed a diet with sodium chloride but not in rats with sodium bicarbonate overload. Thus high sodium intake was responsible for the changes of systemic resistance in DOCA-treated animals and its action was only slightly augmented by a high chloride intake. In contrast to this, the chloride overload seemed to be essential for the induction of increased arterial rigidity.

Animals↗
PubMed1986

Vasoactive role of endogenous digoxin-like factor in rats with experimental hypertension.

Acute blockade of circulating digoxin-like factor endoxin lowered blood pressure (BP) by a decrease in systemic resistance which was partially compensated by an increased cardiac output. The important participation of circulating endoxin in the maintenance of elevated BP was proved in young animals with DOCA-salt and one-kidney, one-clip (1K1C) Goldblatt hypertension but not in young spontaneously hypertensive rats (SHR). In rats with DOCA-salt as well as with 1K1C hypertension, the role of endoxin differed according to the age at which the hypertensive stimulus was applied. The significant role of the "digoxin-like" factor in BP regulation was found only in young animals. On the other hand, in SHR the participation of endoxin in the maintenance of elevated BP rises with the age. High salt intake prior to sexual maturation seems to be critical for later participation of the "digoxin-like" factor in long-term BP regulation.

Age Factors↗
PubMed1986

Acyclovir in the treatment of infection due to herpes viruses.

Intravenous infusions of acyclovir were administered to 15 patients suffering from herpes simplex or varicella-zoster infections. The therapeutic effect of the drug consisted in rapid cessation of progression of the disease and in considerable shortening of duration of clinical symptoms. There were no adverse reaction in our groups of patients. There were no relapses after the treatment with acyclovir had been stopped. From what has been stated above, we take acyclovir for a highly efficient and safe drug for therapy of HSV and VZV infections.

Acyclovir↗
PubMed1986

Salt and experimental hypertension: the influence of age.

In a series of experiments, age-dependent differences in the development of DOCA-saline hypertension (HPT) were studied in the rat. Immature animals developed--in contrast to the adult ones--a more severe and self-sustaining HPT, associated with a more pronounced retention of fluid and a greater increase of renal collagen which was preceded by a more rapid decrease in renal renin content. It is suggested that changes in intrarenal haemodynamics due to the suppression of renal renin-angiotensin system play a role in the pathogenesis of hypertensive renal lesions which develop more readily in immature animals and are responsible for their more severe HPT. Similarly, monkeys exposed to increased salt intake from earliest stages of postnatal ontogeny are also more prone to develop salt hypertension more rapidly than the adult ones. The increased salt intake before sexual maturity may thus be considered as a risk factor for the development of hypertension also in man.

Administration, Oral↗
PubMed1985

The importance of endogenous digoxin-like factors in rats with various forms of experimental hypertension.

The acute administration of anti-digoxin serum (ADS) caused a pronounced long-lasting blood pressure decrease in young DOCA-salt hypertensive rats. The decrease of blood pressure was only moderate in 1K-1C Goldblatt rats while there was no change of blood pressure after the ADS injection in spontaneously hypertensive rats. However, the blockade of endogenous digoxin-like factors lowered blood pressure only in those hypertensive rats which were treated with DOCA-saline from youth but not in animals treated in the same manner only in adulthood. The age period at which salt intake was increased, could be responsible for the susceptibility of animals to salt- and volume-dependent forms of experimental hypertension as well as for the participation of slow acting humoral pressor agents in the induction and/or maintenance of elevated blood pressure. It is evident that endogenous digoxin-like factor(s) participate in a greater response of young rats to the hypertensive stimuli.

Angiotensin II↗
PubMed1985

Endogenous digoxin-like factor contributes to the elevation of systemic resistance in rats exposed to high salt intake from prepuberty.

The acute administration of anti-digoxin serum (ADS) caused a pronounced blood pressure decrease only in those hypertensive rats that were treated with desoxycorticosterone acetate (DOCA) and 1% saline from prepuberty. This was due to a rapid decrease in systemic resistance which was partially compensated by increased cardiac output. There were no similar effects of ADS in rats treated in the same manner in adulthood only. Different mechanisms might be responsible for blood pressure elevation induced by high salt intake in youth or in adulthood. The participation of endogenous digoxin-like factor in the maintenance of elevated systemic resistance in DOCA-salt hypertensive rats is a typical case.

Animals↗
PubMed1984

A different role of digoxin-like factor in the maintenance of elevated blood pressure in rats treated with DOCA and saline in youth or only in adulthood.

The acute administration of anti-digoxin serum (ADS) caused a pronounced long-lasting blood pressure decrease only in those hypertensive rats that were treated with DOCA and 1% saline from prepuberty. There was no effect of ADS on blood pressure of rats treated in the same manner in adulthood only. The age at which salt intake was increased could be responsible for both the susceptibility of animals to salt-dependent forms of experimental hypertension and the participation of slow-acting humoral pressor agents (endogenous digoxin-like factors) in the maintenance of their elevated blood pressure.

Aging↗
PubMed1984

Nacartocin--analogue of oxytocin with enhanced natriuretic properties: natriuretic and hemodynamic characteristics.

Nacartocin, [2-p-ethylphenylalanine]deamino-6-carba-oxytocin, is almost three times more potent than oxytocin as a natriuretic agent. The natriuretic effect is mainly due to the inhibitory action of the peptide on tubular sodium resorption. Nacartocin decreased the blood pressure of anesthetized rats by the decrease of the total peripheral resistance which was greater than that observed after oxytocin administration. In conscious rats, Nacartocin caused a slight but prolonged increase of blood pressure.

Animals↗
PubMed1982

Age-dependent salt hypertension in Brattleboro rats: a hemodynamic analysis.

The hemodynamic effects of 0.6% saline, consumed either from youth (4th week of age) or from adulthood (12th week of age), were studied in unanesthetized, unoperated, and uninephrectomized homozygous female Brattleboro rats. Long-term saline drinking induced a general decrease of blood pressure in unoperated rats which was more pronounced in rats drinking it from youth. The relation of low systemic resistance and high cardiac output (observed at the age of 10-15 weeks) to the high mortality of these rats was discussed. Two phases were recognized in the development of salt hypertension in uninephrectomized rats drinking saline from youth. The increased systemic resistance played a major role during the early phase (13-15 weeks), while changes of body fluids as well as altered arterial compliance contributed to the elevation of systolic blood pressure in the late phase of salt hypertension (20-30 weeks of age). In uninephrectomized rats drinking saline from adulthood, the late blood pressure response was only slightly attenuated in comparison with uninephrectomized rats drinking saline from youth. The absence of increased arterial rigidity in the former group was the only major hemodynamic difference between these two groups of uninephrectomized rats aged 20-30 weeks.

Aging↗