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Biomedical subjects

K Stepniakowski

Publications and source records attributed to K Stepniakowski.

36 records · Page 2Linked to original sources
PubMed1992

[Primary arterial hypertension. Treatment with captopril and function of the left heart ventricle, concentration of catecholamine in blood and activity of renin].

We evaluated the effect of captopril treatment on left ventricular mass (LVM) and function in sustained mild-to-moderate primary hypertension. In 16 men aged 34.5 +/- 6.4 yrs. M-mode echo and pulsed wave Doppler recordings were obtained prior to and after 2 months captopril treatment (50-150 mg daily). No significant changes in heart rate, systolic blood pressure, ejection fraction, fractional shortening, cardiac output, LVM and Doppler-derived indices of mitral inflow were observed. Diastolic blood pressure measured during examination fell from 102.2 +/- 13.3 to 90.3 +/- 9 mmHg (p less than 0.026). No consistent correlations between catecholamines and indexes of left ventricular function were found. Two-month captopril therapy in mild-to-moderate hypertension results in diastolic blood pressure lowering with no effect on LVM or left ventricular function.

Adult↗
PubMed1991

Central ANP attenuates pressor responses to central AVP in WKY and SHR.

Blood pressure and heart rate responses to intracerebroventricular (ICV) injections of atrial natriuretic peptide (ANP, 125 ng) arginine vasopressin (AVP, 10 ng), combination of ANP (125 ng) and AVP (10 ng) or artificial cerebrospinal fluid (acsf, 5 microliters) were compared in conscious normotensive (WKY) and spontaneously hypertensive (SHR) rats. In both strains, ICV injection of AVP elicited significant increase of mean blood pressure (MP) and heart rate (HR). Increase of MP but not of HR was significantly greater in SHR than in WKY (p less than 0.05). Injection of acsf or ANP, as well as simultaneous administration of ANP and AVP, did not elicit significant changes of MP either in WKY or in SHR. In SHR, HR was significantly elevated by ICV injections of AVP and ANP + AVP, whereas in WKY HR was increased only after AVP. The data suggest that interaction of ANP and AVP at a central level may result in significant attenuation of central pressor effects of vasopressin.

Animals↗
PubMed1991

[Atrial natriuretic peptide level in acute myocardial infarction].

Concentration of atrial natriuretic peptide (ANP) was studied in acute myocardial infarction (AMI), its association with ventricular arrhythmias (VA), left ventricular dysfunction and infarct size. Plasma ANP concentrations were measured at time: 0, 4, 8, 16, 24, 48 and 72 hours after admission in 11 patients (pts) with first AMI, up to 6 hours after the first symptoms. Ventricular arrhythmia was assessed by 24 hour Holter monitoring, left ventricular dysfunction by echocardiography and infarct size by serial CK-MB measurement in first 72 hours of AMI. In subsequent measurements the average plasma concentration of ANP (mean +/- SEM) was elevated: 42.2 +/- 9.9, 35.3 +/- 12.5, 33.9 +/- 8.3, 42.3 +/- 8.3, 36.9 +/- 6.4, 60.7 +/- 9.3, 47.8 +/- 12.0 fmol/ml. The maximal plasma ANP concentration was significantly higher (p less than 0.01) in 4 pts with VA 4th grade acc. to Lown than in 7 pts without VA (102.6 +/- 17.9 vs 41.1 +/- 6.4). The maximal level of ANP--153.3 fmol/ml in a patient with paroxysmal supraventricular tachycardia was observed. There were no significant correlations between plasma ANP and infarct size, size of left atrium and contractility disturbances of left ventricle.

Adult↗
PubMed1990

[Effects of 4-hour erect posture and furosemide on the blood level of atrial natriuretic peptide in patients with primary arterial hypertension].

The arterial pressure, the pulse frequency, the concentration of arterial natriuretic peptide (ANP), the aldosterone++ concentration and the plasma renin activity were determined in patients with primary hypertension after administration of furosemide in conditions of active assuming of erect position. The ANP concentration was lowered in that conditions both in the patients and in healthy subjects.

Adult↗
PubMed1990

[Free serotonin level in the blood of patients with borderline and essential hypertension].

Serotonin appears to play an important part in the pathogenesis of essential hypertension. Various studies have shown, that the metabolism of serotonin may be disturbed in some pathological conditions for example in hypertension. It concerns also the changed mechanisms of uptake and release of serotonin. The certain blood vessels may become more hypersensitive to the vasoconstrictor effects of serotonin in patients with hypertension than in normal subjects. During chronic treatment with ketanserin, S2-serotonergic antagonist, blood pressure is reduced in spontaneously hypertensive rats and in humans. This fact can also indicate indirectly, that that serotonin plays a part in the pathogenesis of essential hypertension. The aim of the study was to determine the concentration of free serotonin (S) in the blood of 15 patients with sustained essential hypertension in the mean age 32.8 +/- 1.8, of 23 patients with borderline essential hypertension in the mean age 29.0 +/- 3.0 and of 10 normal subjects in the mean age 31.1 +/- 1.7 years. Plasma free serotonin was determined by fluorometric method. All patients and controls were investigated at the hospital. They were on normosodium diet, without drugs for last two weeks. The fasting blood samples were collected in the supine position. Free serotonin blood concentration was significantly higher in hypertensive group than in normal subjects. The important difference of serotonin blood concentration between two groups of hypertensive patients was noticed. It was significantly higher in group of patients with sustained hypertension, than in group with borderline hypertension (p less than 0.05). Our results are similar to the observations of other authors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Effect of physical exercise on atrial natriuretic factor and plasma catecholamine concentrations in patients with essential uncomplicated hypertension.

Plasma atrial natriuretic factor (ANF) and catecholamine concentrations were determined in 11 untreated patients with uncomplicated essential hypertension and seven normotensive subjects during graded submaximal exercise on a treadmill (loads: I 40%, II 60%, III 80% of maximal oxygen consumption). No significant differences in plasma ANF and catecholamine concentrations were found between the hypertensive and the normotensive subjects. The results do not support the presence of significant differences in the release of ANF and catecholamines during dynamic exercise between patients with uncomplicated essential hypertension and normotensive subjects.

Adult↗
PubMed1989

[Atrial natriuretic peptide in patients with primary arterial hypertension].

Atrial natriuretic peptide (ANP) activity was studied in 33 males with borderline and established essential hypertension. No significant differences of serum ANP concentration were stated in patients with borderline and established uncomplicated hypertension in comparison with the control group.

Adolescent↗
PubMed1989

[Correlations of atrial natriuretic peptide and catecholamine levels in the blood during surgical removal of pheochromocytoma].

Atrial natriuretic peptide concentrations (ANP) were determined in 4 patients with pheochromocytoma during its surgical removal. There was no correlation among ANP level, plasma catecholamines concentrations and blood pressure. Increase of plasma ANP concentration after tumor removal can be explained by simultaneously observed hypervolemia. It proves that ANP secretion mostly depends on enlarged central blood volume.

Adrenal Gland Neoplasms↗
PubMed1988

Atrial natriuretic factor enhances vasopressin-induced bradycardia in normotensive (WKY) but not in spontaneously hypertensive (SHR) rats.

Effect of elevation of blood atrial natriuretic peptide (rat 1-28 ANF) level on pressor responses and bradycardia elicited by vasopressin (AVP) was compared in conscious normotensive (WKY) and spontaneously hypertensive (SHR) rats 14-16 weeks old, instrumented with arterial and venous catheters 1-2 days prior to the experiment. Blood pressure and heart rate were determined before and after i.v. injection of 2.5, 5.0 and 10.0 ng of AVP under control conditions (infusion of saline) and during infusion of ANF at a rate of 0.3 micrograms kg-1 min-1. Administration of ANF did not influence pressor responsiveness to AVP (determined as a maximum increase of systolic blood pressure) neither in WKY nor in SHR, however, it elongated the pressor response to the lowest dose of AVP in WKY. Atrial natriuretic factor significantly enhanced bradycardic responsiveness to AVP (determined as a maximum decrease of HR) in WKY but not in SHR. Reduction of heart rate in relation to the corresponding elevation of the systolic pressure (delta HR/delta SP) was also significantly greater in WKY but not in SHR. This effect was significant when blood pressure increases elicited by AVP did not exceed 40 mmHg. The results suggest that ANF potentiates reflex bradycardia elicited by AVP. This action may be a mechanism buffering blood pressure increases in response to AVP. Absence of this effect in SHR may be related to the impairment of the reflex control of blood pressure in this strain.

Animals↗
PubMedDate not supplied

Effects of vasopressin and V1 receptors blockade on blood pressure and heart rate in spontaneously hypertensive rats.

The aim of the present study was to compare effects of intravenous infusion of vasopressin AVP and V1 receptors blockade on blood pressure and heart rate in normotensive (WKY) and spontaneously hypertensive (SHR) rats. A 20 min vasopressin infusion (1.2 ng/kg/min) elicited significantly greater increase in mean blood pressure (MP) in SHR than in WKY. Heart rate was significantly reduced in SHR while nonsignificantly in WKY. A 20 min dEt2 AVP (V1 antagonist) infusion (0.5 microgram/kg/min) elicited significant decrease in MP and increase in heart rate (HR) in SHR, but produced no effect in WKY. The data indicate that SHR are more susceptible to pressor and hypotensive effects of sustained elevation of AVP and AVP antagonist. The results support the hypothesis that AVP may contribute to pathogenesis of hypertension.

Animals↗
PubMedDate not supplied

[Digoxin-like substance in blood and hypertension in dialysed patients with chronic renal failure].

Concentration of free serotonin, adrenaline, noradrenaline, aldosterone and plasma renin activity have been assayed in blood of 18 patients with the primary arterial hypertension (WHO stage I) and in 10 healthy volunteers. It was found that blood free serotonin and noradrenaline are increased in hypertensive patient. No difference in adrenaline and aldosterone levels and plasma renin activity was seen. No significant correlation between free serotonin and assayed hormones was noted.

Adult↗
PubMedDate not supplied

[Effect of atrial natriuretic factor on arterial blood pressure and frequency of heart contraction in rats with genetically determined hypertension and in normotensive rats].

An effect of peptide released by the heart atria of mammals and called the atrial natriuretic factor (ANF) on blood pressure and heart contractions was studied in rats with genetically determined arterial hypertension (SHR) and in normotensive Wistar-Kyoto rats (WKY). Nine male SHR rats and 11 male WKY rats, aged between 12 and 16 weeks, were given normal saline infusion for 30 minutes through implanted catheters to both ulnar vein and artery. Then, an infusion of ANF at the rate of 0.3 microgram/kg per hour followed for 35 minutes. An infusion of ANF produces significant decrease in the mean arterial blood pressure, systolic and diastolic pressures without significant effect on pulse pressure and heart contractions. AFN infusion with the same rate did not produce any significant differences in the arterial blood pressure and heart contractions in Wistar-Kyoto rats. The obtained results suggest that ANF may play a role in pathogenesis of the arterial blood hypertension.

Animals↗
PubMedDate not supplied

Pressor responsiveness to vasopressin in spontaneously hypertensive rats.

The present study was designed to find out whether pressor responsiveness to vasopressin (AVP) is altered in spontaneously hypertensive rats (SHR) in comparison with their normotensive controls (WKY). Blood pressure and heart rate changes after injection of graded doses of 2.5, 5.0 and 10.0 ng of AVP (Calbiochem) i.v. were compared in 9 conscious, unrestrained spontaneously hypertensive (SHR) and 11 normotensive Wistar Kyoto (WKY) rats, chronically instrumented with venous and arterial catheters. The threshold dose necessary to elicit a significant increase in blood pressure and reduction of heart rate was lower in WKY than in SHR. At each dose level the blood pressure elevation persisted for a longer period in WKY than in SHR. Bradycardia was greater in WKY than in SHR both in absolute terms and in relation to the blood pressure increase. Thus, the results reveal diminished pressor responsiveness to moderate doses of AVP in SHR in spite of suppressed reflex bradycardia. It is suggested that the peripheral action of AVP on the vascular system is attenuated in SHR.

Animals↗