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Biomedical subjects

H Hinghofer-Szalkay

Publications and source records attributed to H Hinghofer-Szalkay.

At least 55 records · Page 3Linked to original sources
PubMed1980

[Investigations concerning postural influences on blood and blood plasma (author's transl)].

Body position exerts considerable influence on transcapillary balance of protein-poor fluid, i.e., on the whole-body Starling equilibrium. Movement into upright position causes hemoconcentration whereas supine position makes hemodilution. This means that the alteration of blood and plasma volume influences, e.g., plasma protein concentration, hematocrit, and blood hemoglobin content. The application of the mechanical oscillator technique for high-precision density measurements on capillary blood and plasma, especially to quantify the time-course of alterations caused by posture, is discussed in this paper. Tilting into upright position (70 degrees) 45 min after recumbency led to an average increase of 6.6% after 10, and of 11.1% of plasma volume after 30 min in 12 test persons. In 13 test persons, tilting back into supine position (0 degrees) after 30-60 min of standing (70 degrees) caused a mean increase of plasma volume amounting 6.5% after 10, and of 10.5% after 30 min. Postural blood density variations showed shapes similar to that of plasma density, indicating blood volume alterations ranging between 5 and 10%. It is emphasized that, as a consequence for clinical practice, the body positioning before and during blood sampling must be taken into consideration especially in case of precise controls of the course of hematological variables, and in case of statistical comparisons among several test groups.

Adolescent↗
PubMed1980

A new miniature plethysmograph to measure volume changes in small circumscribed tissue areas.

With an ultrasonic method tissue layer thickness was measured in man in circumscribed superficial tissue areas where the underlaying bone provided good backwall echos. In a 5 mm tissue layer changes of +/- 0.2% could be reliably detected. Knowing the height of the tissue cylinder between the surface of the skin and the bone allowed to calculate the tissue volume. The ultrasonic probes could therefore serve as miniature plethysmograph. Several probes were attached in the frontal region, sternum, along the vertebral column and along the tibia simultaneously. Changes of the volume content of the superficial shell tissues were induced by orthostasis, water immersion and heat exposure. It was possible to assess quantitatively the volume shifts into or out of the superficial tissues. During orthostasis 166 ml of fluid left the superficial tissues of the cephalad parts of the body and 164 ml could be traced in the dependent parts. Heat exposure was followed by a pooling 140 ml in the tissues studied. The most pronounced tissue volume changes were observed in the forehead region during heat exposure.

Electronics↗
PubMed1980

Fluid volume distribution within superficial shell tissues along body axis during changes of body posture in man: the application of a new miniature plethysmographic method.

In up to six different sides along the body axis during tilting manoeuvres, volume shifts into or out off superficial tissues were followed with a newly developed miniature plethysmograph. It was possible to localize a region where no or only minor volume changes during the tilt table experiments occurred. This region is identical with the Hydrostatic Indifferent Point (HIP) being localized below the apex of the heart in the upper third of abdominal vena cava. Above the HIP fluid is drained out off the tissues during assumption of upright posture whereas below the HIP fluid volume is pooled. The volume changes occurred in two phases. Within the first 5 s in the cephalad parts of the body a rapid decrease occurred, thereafter the volume remained unchanged or even increased; below the HIP within the first 5 s a large volume increase was followed by a slow continuous volume increment. The functional peculiarities of the low pressure system as a whole were visible studying only superficial shell tissues of the body with the non invasive miniature plethysmographic technique.

Blood Circulation↗
PubMed1980

[Measurement of the colloid osmotic pressure from plasma density by means of the mechanical oscillator technique (author's transl)].

The colloid osmotic pressure of plasma is a clinically and physiologically important variable. Like the plasma density, it is a function of the total concentration of plasma proteins. Thus, plasma colloid osmotic pressure can be determined from measurement of the plasma density. Minor variations are caused by variations of the albumin-globulin ratio and, much less frequently, by increased concentration of low molecular substances in the plasma. The direct measurement of the colloid osmotic pressure is a time consuming and complex procedure. The determination of the plasma density using the mechanical oscillator technique is a simple and fast procedure. From our results we were able to derive and prove the applicability of an equation which permits the calculation of the colloid osmotic pressure from the measured values of the plasma density. The plasma volume needed for the measurement is 0.2 ml, the measuring time amounts to a few seconds.

Blood Proteins↗
PubMed1980

[The influence of hemolysis on capillary blood plasma density measurements using the mechanical oscillator technique (author's transl)].

Sampling of capillary blood often yields slightly hemolytic plasma. We investigated the influence of hemolysis on plasma density using the mechanical oscillator technique. Plasma density rose by approximately 0.1 milligram when the hemoglobin content increased by 0.5 milligram. These values correspond to 0.3% hemolysis and were not exceeded in more than 70% of the investigated capillary plasma samples. In general, hemolysis must be taken into account if plasma density measurements are to be made with an accuracy better than 0.5 milligram, which corresponds to 2-3% of the plasma protein content.

Adolescent↗
PubMed1979

[Continuous determination of the blood density during haemodialysis (author's transl)].

Application of the mechanical oscillator technique for measurement of blood density, in combination with a reference method for the determination of the absolute value of the blood volume, enables precise and continuous monitoring of fluid shifts during haemodialysis. The significant correlation between blood volume and density or plasma volume and density allows each variation in blood volume to be calculated from the blood density and the slope of the regression line for each individual patient. The possibility of taking continuous measurements and the high accuracy of the mechanical oscillator technique commends this method for the measurement of short-term and small fluid shifts.

Blood Pressure↗
PubMed1979

[Application of the mechanical oscillator technique for the measurement of blood density and hematocrit (author's transl)].

Density measurements were performed with an accuracy of 0.01 g/l by means of a density meter based on the "mechanical oscillator technique", on human whole blood, on plasma, and on erythrocyte concentrates. A highly significant correlation between blood density and hematocrit was found. If plasma and red cell densities are known, hematocrit can be estimated more precisely than using the centrifugation method. This fact is important if small variations of the hematocrit are to be determined. Such variations can be produced, e.g., by alteration of the transcapillary filtration equilibrium. Furthermore, the statistical distribution of plasma and erythrocyte densities allows to determine the range of variation of blood densities for certain hematocrit values and vice versa.

Blood↗
PubMed1979

[Feedback by objective tests for coordination of medical teaching (author's transl)].

Within the framework of an experimentally introduced curriculum in Medical Physiology during the past three years, voluntary tests of the multiple-choice type were offered at the end of each term in order to provide students with feedback on their achievements. Positive results contribute to the final grade. Analysis of test results reveals improvement after the first year; results of subsequent tests are fairly stable. Selected items are presented in detail in order to show the distribution of choices. As revealed by item analysis the attractivity of distractors seems to be of a specific nature. Statistical results and interpretation of content of questions derived from different fields indicate that valuable feedback might be obtained from objective tests when interdisciplinary coordination of the curriculum is to be achieved.

Austria↗
PubMed1979

[Physiology of carbohydrate absorption (author's transl)].

The only enzymatic mechanism concerning carbohydrates in the chymus is starch decomposition by enzymes in the saliva and pancreatic juice, In contrast to the chymus the enterocytes dispose of all necessary enzymatic activities in their brush border, above all for disaccharide splitting. Furthermore these activities show relatively fast physiological adaptation. The activity of the disaccharidases and the transport of glucose depend on luminal sodium concentration. The transport of glucose and galactose takes place by active mechanisms, the transport of fructose by facilitated diffusion, other monosaccharides are absorbed passively.

Biological Transport↗