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At least 19 recordsLinked to original sources
PubMed1992

Enhanced localization of liposomes with prolonged blood circulation time in infected lung tissue.

In an experimental model of unilateral pneumonia caused by Klebsiella pneumoniae in rats we investigated whether intravenous administration of liposomes with prolonged blood circulation time resulted in significant localization of liposomes in infected lung tissue. Liposomes (100 nm) composed of hydrogenated phosphatidylinositol:hydrogenated phosphatidylcholine:cholesterol (molar ratio, 1:10:5) radiolabeled with gallium-67-deferoxamine showed relatively long blood circulation time. The degree of localization of these long circulating liposomes in the infected left lung was significantly higher compared to that of localization of 110 nm egg phosphatidylglycerol:egg phosphatidylcholine:cholesterol (molar ratio, 1:10:5) liposomes which exhibited relatively short blood circulation time. At 16 h after administration of the long circulating liposomes (when 10% of the injected dose was still present in the bloodstream) localization of liposomes in the infected left lung was increased up to 10-fold compared to the left lung of uninfected rats, and appeared to be highly correlated with the intensity of the infection. In the uninfected right lung the localization of long circulating liposomes was not increased. The degree of localization of liposomes in the infected tissue is dependent on the residence time of liposomes in the blood compartment. The extent of localization of long circulating liposomes in infected tissue appeared to be dependent on the liposomal dose administered.

Animals↗
PubMed1977

[Automated method of determining blood circulation time in nuclear medicine cardiology].

In this paper a method of computer-assisted evaluation of circulation times using a scintillation camera is described. Eight segments of the central circulation are defined on a graphic display unit. Then the analysis of time-activity curves and the normalization of circulation times to hear rate is performed. The automatic analysis is based upon the hydrodynamic meaning of the first inflection point of a time-activity curve. The differences between inflection points are nearly identical with appearance time differences under the experimental conditions used in 131 cases. A mathematical model is presented to defined the conditions for this behaviour and to explain some deviations observed if time differences exceeded a certain value. It can be shown that the method described is largely independent of extraneous influences. It offers haemodynamically relevant parameters that correspond to the minimal cardiac transit times.

Blood Circulation Time↗
PubMed1976

[Reproductibility of the true measurement of blood volume, cardiac output, mean pulmonary circulation time and pulmonary blood volume by radiocardiography].

Radiocardiography provides a simple method of measurement of blood volume, cardiac output, mean pulmonary circulation time, and pulmonary blood volume. The use of a computer allows the results to produced immediately provided that the circulating blood volume is measured during the test anpd that the radiocardiographic tracing is analysed by an entirely automatic method. The reproducibity of the results given by this automatic method has been studied in 35 patients, two measurements being made at 20 minute intervals. The standard deviation of the percentage difference between consecutive measurements was 5.8% for the blood volume, 10.4% for the cardiac output, 8.8% for the mean pulmonary circulation time, and 9.7% for the pulmonary blood volume.

Adolescent↗
PubMed1977

Hereditary determination of several hemodynamic indices.

Investigation of the genetic determination of hemodynamic indices (the volume of circulating blood, the time of total blood circuit, the rate of lesser blood flow and the minute heart volume) is carried out in 16 mono- and 15 dizygotic twin pairs. The volume of circulating blood only was found to be highly genetically determined (G = 0.90). The role of heredity and environment was almost the same in genesis of the time of total blood circuit and the rate of lesser blood flow (G = 0.34 and 0.48 respectively), while the effect of environment is prevailed for the minute heart volume. The coefficient of genetic determination G is considered to be the most competent estimate among other indices of heredity, because it makes possible to isolate the additive variance and the variance of determing genetic component of phenotypical dispersion of a character. On the basis of the parameters studied, a multifactorial character of hemodynamics indices inheritance is suggested.

Adult↗
PubMed1978

Dependency of transcoronary circulatory transport function on coronary perfusion pressure and flow.

Transcoronary circulatory transport function was computed from the dye-dilution curves recorded simultaneously at the entrance (aortic root) and exit (coronary sinus) of the coronary circulation after the injection of dye bolus into the femoral vein in open-chest dog. The effect of coronary perfusion pressure and flow on the first (delta-t) and second (deltapi2) moments of the transport function was examined before and during intra-aortic angiotensin infusion. It was observed that the relative dispersion (deltapi2 1/2/delta-t) in the canine coronary circulation is the largest among the organ-circulations that have been examined by the investigators, suggesting that cardiac wall is highly heterogeneously perfused, and that the relative dispersion was variable depending on the coronary perfusion pressure and flow. It is concluded that sole measurement of the moment of transcoronary transport function such as -t cannot be a reliable indicator of the coronary circulatory disturbances. The underlying mechanisms for the dependency of the relative dispersion on the perfusion was discussed.

Animals↗
PubMed1976

Hepatic blood flow and cardiac output after porta-caval anastomosis in the rat.

Investigations were performed in rats with portacaval anastomosis (PCA) in order to measure hepatic hemodynamics and cardiac output (CO) 3, 6, 14 and 28 days after operation under pentobarbitone anesthesia using the flow fraction distribution method (131I-MAA) of CO. The latter was calculated using Vierordt's principle from blood volume (BV) (125RIHSA-dilution method) and ICG-appearance time (ICG-AT) (ear-densitometry). Even 3 days after PCA CO was increased to 38.7 +/- 5.0 (SD) ml/min/100 g b.w. (normal 23.8), due to an increase of BV from 6.3 +/- 1.4 to 7.5 +/- 0.6 ml/100 g b.w. and a decrease of ICG-AT from 3.6 +/- 0.4 to 2.8 +/- 0.5 s. Arterial hepatic flow fraction of CO increased to 8.7 +/- 2.8% (control: 5.5 +/- 2.4%). Changes could be observed up to day 28. Hepatic blood flow per g liver tended to stabilize but was still decreased at day 28: 1.5 +/- 0.6 ml/min/g liver (control: 2.0 +/- 0.3). The typical hemodynamic changes in human liver cirrhosis can be reproduced by PCA alone. They are considered to be compensatory mechanisms for a reduced portal liver blood flow, which are not found to compensate completely.

Animals↗
PubMed1978

[General and cerebral hemodynamics in atherosclerosis of the cerebral vessels with transient disorders of cerebral circulation].

The authors studied general and cerebral hemodynamics in 51 patients with cerebral atherosclerosis transient disorders of cerebral circulation. The studies demonstrated correlation between the indices of general peripheral resistance of the blood flow, cardiac and pulse indices. The rate of the blood flow in the segment hand-ear was slower. REG studies detected deficit of blood repletion, intrahemispheric asymmetry, a drop in the elasticity of the vascular wall. These data may be used in prescribing pathogenetical treatment to patients with transient disorders of cerebral circulation.

Aged↗
PubMed1977

Carotid-vertebral artery blood transit time in health and in neurological patients: a preliminary study by a non-invasive impedance method.

Thirty-one healthy subjects and nineteen neurological patients covering a range of chronic neurological and neurovascular syndromes were examined by an electrical impedance method. Two estimates of carotid-vertebral artery transit times were measured: one time taken between the Q wave of the EKG to the commencement of the next succeeding impedance pulse-volume wave (CT1), and the other, this estimate together with the time to maximum point of the impedance wave (CT2). Results indicated prolonged circulation times for the patients as compared with the controls without relevance to age in the case of CT1, although transit times did increase with age for CT2. It is suggested that this impedance technique may be valuable in the initial screening of transient cerebral ischaemia.

Adolescent↗
PubMedDate not supplied

[The contractile capacity of the myocardium, the effect of insulin on it and indices of central hemodynamics in patients with diabetes mellitus].

In comparing the indices in 105 patients with diabetes and in 75 healthy persons a possibility was revealed of significant disturbances of the contractile function of the myocardium also in young patients with diabetes without any clinico-instrumental signs of coronary atherosclerosis. This proves the significane not only of atherosclerotic changes in the development of myocardial pathology in diabetes, but alos of the metabolic ones. Against the opinion of some authors, when given in the usual therapeutic doses insulin failed to lead to negative shifts in the phasic structure of the left ventricle systole in diabetics. For the first time investigations of hemodynamics by the method of diluted Evans blue demonstrated an increase in the plasma volume and of the circulating blood mass, and a decrease of circulation velocity in diabetes.

Adult↗