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Biomedical subjects

H Landgraf

Publications and source records attributed to H Landgraf.

At least 55 records · Page 3Linked to original sources
PubMed1982

[Effect of vincamine on blood viscosity].

Pervincamine has been launched since several years for the therapy of cardiovascular disease. As the mechanism of efficacy is not known very well it has been investigated whether the substance has a favorable influence on the rheology of the blood in in vitro studies. The addition of different concentrations of Pervincamin to normoosmolar blood samples showed no change of the rheology of blood in vitro. Under hyperosmolar loading conditions as they can be found comparatively in the blood of the microcirculation of an ischemic working muscle, a statistically significant improvement of the filtration of erythrocytes can be found which is largely due to an improvement of the flexibility of the erythrocyte. These investigations show that Pervincamin effects favorably rheological properties under certain conditions. Further analyses are necessary in order to elucidate the relation between cerebrovascular insufficiency on one hand and the vincamin induced improvement of rheology on the other.

Arterial Occlusive Diseases↗
PubMed1982

[Improvement of the flow properties of the blood of patients by low-molecular hydroxyethyl starch (Expafusin)].

10 patients with various diseases causing elevated ESR-values and impaired flow properties of blood received infusions of 500 ml of low molecular weight hydroxyethylstarch (HES 6%, Expafusin) within approximately 30 minutes. Measurements of rheological parameters for several hours after infusion showed a statistically significant decrease of apparent whole blood viscosity and of plasma viscosity. RBC aggregation was slightly, but statistically significantly reduced, whereas RBC filterability remained unchanged. These data obtained with blood from patients with altered flow properties of blood agree very well with former results obtained in healthy volunteers.

Adult↗
PubMed1981

Erythrocyte filtration and smoking.

Erythrocyte filterability may be influenced by 'acute' smoking with subsequent changes of RBC filterability and by chronic inhalation of cigarette smoke which may lead to chronic alterations. To evaluate chronic alterations of RBC deformability we compared the erythrocyte filtration rates of 60 young, healthy chronic smokers (30 female, 30 male) with those of 60 young, healthy non-smokers (again 30 female and 30 male). The comparison showed a higher filtration rate in the male non-smokers group than in the group of the male smokers, the difference however was not statistically significant. Female smokers and non-smokers did not show any noticeable difference in their RBC filtration rates.

Adolescent↗
PubMed1981

[Effect of an infusion with middle molecular weight hydroxyethyl starch (HAES-steril 10%) on the flow properties of blood in healthy probands].

Ten healthy volunteers received infusions of 500 ml of a 10% solution of middle-molecular-weight hydroxy-ethyl-starch (HES 200, HAES-steril 10%) within 30 min. Measurements of hemorheological parameters before and up to 3 hrs after infusion revealed a statistically significant decrease of whole-blood viscosity and a slight, but also statistically significant increase of plasma viscosity. RBC filterability and RBC aggregation remained unchanged. The data presented show that despite of a relatively high molecular weight of the infused HES-solution which is responsible for the relatively long intravascular persistence, the flow properties of blood as a whole are positively influenced.

Adult↗
PubMed1980

Adaptive responses of rat liver to the gestagen and anti-androgen cyproterone acetate and other inducers. III. Cytological changes.

Treatment of rats with cyproterone acetate (CPA) induces liver growth. Intact hepatocytes and cell nuclei were isolated from enlarged livers and their volumes or diameters were determined by electronic and microscopic methods. No changes in mean hepatocyte volume or ploidy were observed. However, there was a marked fall in the frequency of binuclear hepatocytes (from 43% to 7%) and a concomitant increase of nuclear ploidy. This effect probably resulted from CPA-induced replication of binuclear hepatocytes. The total number of hepatocytes replicating in response to CPA was estimated on the basis of these data and was found to be up to 75% of all parenchymal cells. Similar cytological changes were observed in the liver after treatment with pregnenolone-16 alpha-carbonitrile (PCN) and, to a lesser extent, with alpha-hexachlorocyclohexane (alpha-HCH). In contrast, physiological liver growth in adolescent rats was characterized by only small changes in binuclearity and nuclear ploidy, and by increases of cellular ploidy. Thus, ploidy analyses may be a useful tool to characterize the type of growth stimulation. Following discontinuation of treatment the cytological changes induced by CPA or alpha-HCH were not reversible in a matter of 3 weeks.

Adaptation, Physiological↗
PubMed1980

[Oxygen tension in the arterial blood and in muscle tissue in healthy persons of different age (author's transl)].

According to Loew and Thews the oxygen tension in the arterial blood is clearly related to age. The average value for younger persons (age 18-30 years) was 93.7 mmHg whereas the values for the older persons (in this comparison age 50-60 years) was only 76.9 mmHg. Measurements of tissue pO2 in the tibialis anterior muscle did not show statistically significant differences between younger (age 20-30 years, pO2: 32,2 +/- 7,4 mmHg) and older persons (age 50-60 years, pO2 27,2 +/- 4,4 mmHg) who did not suffer from chronic occlusive arterial disease.

Adolescent↗
PubMed1979

[Improvement of blood viscosity after infusion of low-molecular hydroxyethyl starch (Expafusin) in healthy subjects].

In healthy volunteers, 500 ml of a 6% low molecular weight hydroxyethyl starch solution (Expafusin) was infused intravenously within 30 minutes. Blood samples for the measurement of rheological parameters were obtained before and after the infusion. Blood and plasma viscosity were significantly decreased after the infusion of HES. Red cell deformability as measured by a filtration technique was slightly improved. Red cell aggregation as measured by a light transmission method was markedly reduced. Repeated infusion of 500 ml Expafusin indicates that the improvement of the flow properties of blood can be maintained for more than 3 hours.

Adult↗
PubMed1978

[Trichinosis: epidemiology, clinical features and diagnosis (author's transl)].

After ingestion of wild boar meat 58 patients developed typical clinical signs and symptoms of trichinosis. All patients had marked blood eosinophilia. In 45% of the patients GOT and GPT and in 62% HBDH were moderately increased, while in 76% LDH and in 86% creatine-kinase showed abnormally high values. CK-MB was increased in three patients. 92% of muscle biopsies showed typical morphological changes in skeletal muscles. Latexagglutination, complement-fixation and agar-gel diffusion tests were not reliable. In most of the examined cases clinical symptoms and histological results correlated well with the indirect haemagglutination test, the microprecipitation test with living larvae of Trichinella spiralis and evidence of specific antibodies (IgG, IgM, IgE) by indirect immunofluorescence and the ELISA technique. 25 patients were treated with thiabendazole (Minzolum), 19 of them successfully.

Alanine Transaminase↗
PubMed1977

Effect of hypophysectomy on the stimulation of liver growth by alpha-hexachlorocyclohexane, phenobarbital, and partial hepatectomy in the rat.

alpha-Hexachlorocyclohexane (alpha-HCH) or phenobarbital (PB) elicit growth and cell multiplication in rat liver. In hypophysectomized rats, alpha-HCH and PB induce an increase in liver mass, but no increase in liver DNA. Hypophysectomy without additional treatment results in a decrease of liver size and RNA, while the DNA content remains unchanged, thereby leading to a relative DNA surplus. 1/3-hepatectomy in hypophysectomized animals leads to a small increase of hepatic DNA only; after 2/3-hepatectomy 75-80% of the original liver DNA are restored. In rats with intact hypophysis losses of liver DNA are known to be restored completely. The findings suggest that the relative DNA surplus in hypophysectomized rats prevents the stimulation of DNA synthesis by weak growth stimuli such as alpha-HCH, PB, and 1/3-hepatectomy. If the relative DNA surplus is eliminated by partial hepatectomy, the inducers do produce DNA multiplication. It is concluded that the induction of liver growth and cell multiplication by alpha-HCH and PB does not require the presence of the hypophysis or one of its hormones.

Animals↗
PubMed1976

Changes in size, DNA content, and nuclear ploidy of rat liver produced by the environmental microflora.

Effects of the environment microflora on rat liver were studied in the present investigation. Rats born under sterile conditions were bred either in a germfree or in a "SPF" environment. At 12 weeks of age the liver of the SPF rats was larger by 20% and contained more DNA than germfree rat liver. Volume analysis, by means of a particle counter, of isolated nuclei suggested that the increase of DNA was due to an increase of hepatic nuclear ploidy. The findings show that infections may influence liver size and ploidy. They indicate that the state of infection should be controlled in animal studies which concern the regulation of liver growth and ploidy or which use liver weight and DNA as reference standards.

Animals↗