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Biomedical subjects

V Sinz

Publications and source records attributed to V Sinz.

18 recordsLinked to original sources
PubMed1996

Brachial and digital artery pulse pressures in hypertensive and normotensive subjects.

OBJECTIVES AND PATIENTS: To determine whether or not the pulsatile component of blood pressure (BP) measured centrally and peripherally allows a separation between hypertensive and normal subjects, as well as within hypertensive and normal subjects, as well as within hypertensive patients. We tested the hypothesis that the difference in central and peripheral pulse pressures is increased in hypertensive, compared to normotensive persons, and that this component is influenced by genetic variance. We studied 46 hypertensive patients and 56 age-matched normal subjects, as well as 10 hypertensive families with 74 members of the same age range. DESIGN: Pulse pressure was measured at the brachial artery and the digital artery in the standing and supine position. The difference in the pulse pressures between these sites was calculated. Further, digital volume-pulse amplitude and stroke volume measurements were determined with impedance plethysmography. RESULTS: The differences between central and peripheral pulse pressures were similar in hypertensive patients compared to normal subjects, regardless of posture. However, in the standing position the frequency distribution of this variable in hypertensive patients was bimodal and split into two significantly different distributions (P < 0.05) with peaks at -24 mm Hg and -1 mm Hg, compared to a single peak at -11 mm Hg in normal subjects. Furthermore, these two subgroups of hypertensive patients differed in their brachial systolic BP (127 +/- 10 vs 134 +/- 12 mm Hg; P < 0.05), their brachial pulse pressures (32 +/- 8 vs 42 +/- 8 mm Hg; P < 0.05), and in their peripheral compliance (1.59 +/- 0.92 vs 2.21 +/- 1.00 microliter/mm Hg per 100 ml tissue; P < 0.05). The frequency distribution of pulse pressure differences was also bimodal in members of hypertensive families, even though most (46 out of 74) were normotensive. CONCLUSION: The difference between the digital and brachial pulsatile component may be a useful intermediary phenotype in essential hypertension. Furthermore, the nonuniform decreases in arterial compliance exhibited by our patients may be of pathogenic significance.

Adult↗
PubMed1995

Compliance of the digital artery is decreased in patients with essential hypertension.

The compliance of the arterial vascular system is decreased in hypertensive subjects. On the other hand, the vessel wall properties such as compliance depend on blood pressure (BP). The aim of the present study was to determine the compliance of the digital arteries and to test the hypothesis that decreased compliance is either caused by a downward shift of the compliance-pressure relation or, alternatively, by a change in the compliance-pressure relation itself. We used impedance plethysmography and a finger BP measuring device to determine beat-to-beat the pressure-pulse amplitude (delta P), the volume-pulse amplitude (delta V) and the compliance from digital arteries of 10 hypertensive patients and 10 similarly aged normal subjects. The mean local blood pressure (MLBP) in the digital arteries was changed by vertically varying the position of the right hand in relation to the heart. The compliance of the digital arteries in hypertensive patients (2.76 microliters/mm Hg per 100 ml tissue) is significantly (P < 0.05) decreased compared with that in normal subjects (4.03 microliters/mm Hg per 100 ml tissue). A reduction of MLBP by 50 mm Hg leads to an increase of compliance in normotensive subjects from 4.03 to 12.68 microliters/mm Hg per 100 ml tissue but in hypertensive patients only from 2.76 to 6.16 microliters/mm Hg per 100 ml tissue. The slope of the curve in the low pressure range was also markedly decreased in hypertensive patients compared with controls. We conclude, that the compliance-pressure relation is not merely shifted but also extensively alterated in hypertensive patients.

Adult↗
PubMed1990

[The effect of the oxygen content of the air breathed in on the passive electrical properties of muscle tissue].

Due to a want of oxygen in the breathing air there appears a change of the volume of muscle cells, of ion concentrations inside and outside the cells as well as disturbances the structure and membrane potential. These changes are connected with changes of the passive electrical properties of the muscle tissue. Measuring the electrical impedance of the muscle it is possible to diagnose alterations as shock and disorder of microcirculation in an easy way continuously. Investigations with rats show that a decrease of the oxygen content in the inspiration air effects characteristic changes in muscle impedance. These changes are reversible in normoxia.

Animals↗
PubMed1987

[Transcutaneous and intracutaneous pO2 measurements in the assessment of peripheral arterial occlusive diseases].

The purpose of the study was to compare the results of intra- and transcutaneous pO2-measurements of patients suffering from an arterial occlusive disease of the lower extremities (Fontaine I-IV) with that of 20 healthy volunteers. The measurements were performed by one transcutaneous and two intracutaneous pO2-electrodes on the dorsum of the foot. As reference we used the ratio pf/pft of the venous occlusion plethysmography of the calf. Already at rest the transcutaneous pO2 allows a significant separation of healthy persons and patients of Fontaine II. After a 3-minute ischemic period the greatly changed time parameters 'delay-time', 'half-time of the pO2 increase' as well as the 'pO2 recovery time' permit a significant separation of Fontaine III from healthy persons and Fontaine II. The findings show that both methods complete one another. The value of a local pO2 measurement for an individual therapy control is emphasized.

Arterial Occlusive Diseases↗
PubMed1985

[Spontaneous and provoked changes of the impedance plethysmographic volume pulse and its interpretation].

The stroke volume of every heart beat causes a volume wave travelling towards the periphery. Recordings of the volume pulse were performed with the impedance plethysmographic techniques. The volume pulse contour shows in general a few humps, not only one dicrotic hump. The discussion of pulse recordings performed under normal conditions and in provoked pathophysiological states led to the conclusion that the superposition of reflected waves does not give a sufficient explanation of the genesis of pulse contours in general. The contour of the volume pulse can be simulated by damped oscillations of a volume surrounded by an elastic wall with internal friction.

Adult↗
PubMed1982

[Intra-extracellular ion changes in heart and skeletal muscle in experimental hemorrhagic shock].

An experimental shock model with rabbits and dogs was used (bleeding to an constant systemic pressure of 5.3-6.6 kPa) to investigate quality and time dependency of intra-extracellular gradients of Na+, K+ and Ca++ in skeletal and heart muscle. We found the ion gradient changes to be earlier and more pronounces in skeletal than in heart muscle, where strongest changes appear within the heart ears and significant smaller ones within ventricular and papillar muscles. Unexpectedly there was in heart and skeletal muscle the same two phasic ionic course, and a close correlation between ion gradient changes and shock duration in skeletal muscle. There is a good agreement between our results and the common clinical observations of ventricular arrhythmia caused by acute hypotonic circulatory situation and therefore the early restoration of the disturbed transcapillary exchange in the peripheral circulation is demanded.

Animals↗
PubMed1976

[Function of the liver reticuloendothelial system in hemorrhagic shock in dogs].

The function of hepatic reticulo-endothelial system at normal circulation and during hemorrhagic shock was examined in 13 dogs. The results were as follows:1.198Au-colloid liver scintigraphy demonstrated no essential alterations by shock. A trifling diminution caused by the diminished blood amount in the liver was found at heavy blood loss. The spleen was opcified in no case. 2. The elimination rate, resp. the blood clearance, of 198Au-colloid remained constant during the first 2 hours, proving that the vital clearance function of hepatic reticulo-endothelial system is completely maintained in this phase of hemorrhagic shock. After longer duration of hypovolemic shock (5 hours) elimination rate decreased. 3. It can be concluded that hepatic circulation at first alters according to the blood volume. 4. Consequently, functional testing of hepatic reticulo-endothelial system is not fit for early diagnosis of shock.

Animals↗
PubMed1975

[Vibrational and coupling characteristics of psychophysiological function rhythms in patients with Fallot's tetralogy before and after correction of the cause].

In 24 patients (aged from 5 to 21 years) afflicted with the tetralogy of Fallot and in 11 healthy subjects of the same age, the authors studied, using correlation and spectrum analysis, the coupling and the vibrational behaviour of modulated oscillations (in a rhythm of ca. 1 min.) of some psychophysiologic functions (heart and respiratory rates, blood pressure, sensomotor reaction times, short-time memory for ten-digit numbers) as expression of the central nervous coordination. The examinations were performed when the individuals were in the lying position, in the erect position and again at rest, during 10--30 min. In the subjects afflicted with the tetralogy of Fallot, the degree of synchronization or coupling (35%) was significantly lower than in the control subjects (65%). The decrease in the degree of coupling under orthostatic load was significant (P = 0.05) only in in the patients. One year after causal correction, the degree of coupling was normal (63%). From more than 400 autocorrelation functions and performance spectra (calculated to verify frequency and performance) it was deduced that the mean cycle of oscillation of the 1-minute rhythm was significantly shorter in the pre-operative state than in the postoperative state and in the control subjects. A change from the lying to the erect position manifested itself by a non-significant tendency towards period extension. The frequency deviations occurring in case of cyanotic vitium are discussed as an expression of the overall frequency behaviour of the oscillations which are continuously generated in coupled metabolic multienzyme systems, e. g., in case of anaerobic energy generation.

Adolescent↗