Search PubMed⌕ Search

Biomedical subjects

W Heller

Publications and source records attributed to W Heller.

At least 127 records · Page 7Linked to original sources
PubMed1981

[Carbohydrate metabolism in brain and liver tissue following experimental vascular suturing of the right carotid artery (author's transl)].

Experiments with Wistar rats have been performed in order to analyse brain and liver metabolism after suturing of the rats right carotid artery. It should be figured out how much an interruption of the bilateral blood supply of the brain during end-to-end-anastomosis of a carotid artery would interfere with normal brain and liver metabolism. General anaesthesia of all animals was obtained with pentobarbital. The vascular anastomoses have been performed by using the microsurgical technique. Groups of animals were formed in order to analyse metabolism after various periods of postoperative survival. Brain and liver tissue was removed and the metabolism stopped immediately by freezing the tissue in liquid nitrogen. Biochemical analysis showed several highly significant changes of levels of values indicating hypoxia. Additional experiments have been carried out in order to find out whether hypoxia could be detected in other organs of the body such as the liver after performing the same microsurgical procedure on a carotid artery and how pronounced these changes would be compared to those of brain metabolism. Results of experiments performed up to now indicate that hypoxia also develops in liver tissue.

Animals↗
PubMed1981

[Parenteral nutrition in polytrauma - comparison between a fat-free and a fat-containing nutritional regime].

Two groups of patients with multiple injuries were treated with high-caloric parenteral nutrition over a period of 10 days. One group received amino acids (1 g/kg BW/day) and dextrose (2.0 x resting metabolic rate calories). In the other group dextrose was partially substituted by an isocaloric amount of lipids (2 g/kg BW/day). As for blood and serum glucose, pyruvate, lactate, triglycerides, cholesterol, phosphatides, free fatty acids, glycerol, acetoacetate and beta-hydroxybutyrate there were no significant differences between the two groups. Nevertheless, in the lipid group more balanced blood-sugar levels were seen with smaller amounts of insulin to be needed. This suggests a beneficial effect on the carbohydrate metabolism.

Adolescent↗
PubMed1979

Flavanone synthase from Petroselinum hortense. Molecular weight, subunit composition, size of messenger RNA, and absence of pantetheinyl residue.

Flavanone synthase from irradiated cell suspension cultures of parsley was purified to apparent homogeneity. Molecular weights of about 77 000 for the enzyme and about 42 000 for the subunits were determined respectively by sedimentation-equilibrium measurements and disc-gel electrophoresis in the presence of dodecyl sulfate. A specific antiserum was prepared for the enzyme and was used in an assay for flavanone synthase mRNA activity in partially purified RNA preparations. The apparent molecular size of flavanone synthase mRNA was estimated by sucrose gradient centrifugation and gel electrophoresis under partially denaturing conditions. Values of about 17 S and Mr = 0.62 X 10(6) were obtained. The fractionation patterns suggested that flavanone synthase mRNA was homogeneous in size. All together, the results support the idea that the enzyme is composed of two subunits which are probably identical. Amino acid analysis and a microbial assay were carried out to test the possible occurrence of cysteamine, beta-alanine, and pantothenate in the enzyme. The results were negative, indicating the absence of pantetheine or a similar residue. The possible similarity in mechanism between flavanone synthase and 3-oxoacyl-(acyl carrier protein) synthase is discussed.

Acyltransferases↗
PubMed1979

Metabolic events in acutely damaged brain and the effect of dexamethasone in guinea pigs.

The effect on 210 guinea pigs of a special clinically used compound on substantial brain damage was evaluated. Cerebral metabolism was well preserved in small laboratory animals after blunt head injury by the administration of dexamethasone intraperitoneally. The high doses used were similar to those employed for cerebral contusion of the brain in patients. The concentrations of glucose, lactate, pyruvate and ATP were maintained better in cerebral tissue by pre- and post-traumatic use of dexamethasone than by treatment with a placebo. Analysis of the blood showed no such correlation indicating that the effect of dexamethasone was due to a local effect on the central nervous system, rather than a systemic effect. With rapid freezing, brain tissue from guinea pigs exposed to high doses of systemic dexamethasone was found to contain less lactate and pyruvate compared with untreated controls. ATP was preserved at the original non-traumatic level. This was not accompanied by an increased rate of glycolysis since the glucose level in the damaged brain was not affected by the glucocorticoid.

Adenosine Triphosphate↗
PubMed1979

Ultrastructural and biochemical changes of human papillary heart muscle during different methods of induced cardiac arrest.

To determine the protective effects of different methods of cardioplegia, studies on ATP/lactate levels and ultrastructure were performed in human papillary muscles obtained during mitral valve replacement. In group I (n = 5), plain ischemic arrest in hypothermia (systemic venous temperature = 24 degrees C) was accomplished. In group II (n =12), the heart was arrested by injection cardioplegia using magnesium-aspartate-procaine at systemic venous and myocardial temperatures of 24 degrees C. In group III (n = 12) Bretschneider infusion cardioplegia at systemic venous and myocardial temperatures of 26 degrees C and 19 degrees C respectively was applied. With regard to ultrastructural changes there were no clearcut differences in the three methods of hypothermic cardiac arrest after 60 minutes of ischemia. Ischemic changes tended to be slightest in group III (infusion cardioplegia). ATP decay and lactate increase were significant in group I and moderate to minimal in groups II and III after the same period of time. It is concluded that for aortic cross-clamp times up to 60 minutes, body hypothermia and injection cardioplegia using magnesium-aspartate-procaine at a myocardial temperature of 24 degrees C provide adequate protection of the myocardium. For ischemia times beyond 70 minutes, profound myocardial hypothermia below 20 degrees C is preferred.

Adenosine Triphosphate↗
PubMed1979

Enzymes of General Phenylpropanoid Metabolism and of Flavonoid Glycoside Biosynthesis in Parsley: Differential Inducibility by Light during the Growth of Cell Suspension Cultures.

Several enzymes of phenylpropanoid metabolism showed large changes in their inducibility by light during the growth cycle of cell suspension cultures from parsley (Petroselinum hortense Hoffm.). Two of the three enzymes of general phenylpropanoid metabolism (group I) and six of the approximately 13 enzymes of the flavone and flavonol glycoside pathways (group II) were investigated. Both enzymes of group I (phenylalanine ammonia-lyase and 4-coumarate:coenzyme A ligase) were most efficiently induced at two different stages: first, soon after starting a new culture, and second, near the beginning of the stationary phase. In contrast, the enzymes of group II (acetyl-coenzyme A carboxylase, flavanone synthase, chalcone isomerase, UDP-apiose synthase, and at least one of two malonyltransferases) were maximally induced during exponential growth of the culture. This result supports the conclusions drawn from previous data that the two groups are regulated differentially and that the enzymes within each group are regulated in a coordinated manner.

Journal Article↗
PubMed1979

Urinary hydroxyproline in healthy patients and in prostate patients with and without bone metastases.

An essential part of the classification of prostate carcinoma is the diagnosis of bone metastases. This was done with 70 patients using x-ray analysis, scintography, determination of the acid and alkaline phosphatase, and pelvic crest biopsy, as well as aspiration of the pelvic and sternal bone marrow. In addition, the hydroxyproline concentration was determined in the 24-hour-urine. The study, which was initially undertaken on a sample group (n = 145), yielded a high correlation between age and sex and hydroxyproline values. Women before menopause show significantly lower values than do men of the same age. The data on patients with prostata cancer (n = 70) showed that patients with and without bone metastases, who had been treated with estrogens, had a significantly lower quantity of hydroxyproline than did patients who had not received estrogen therapy. Patients with skeletal metastases (n = 24) showed significantly higher hydroxyproline excretion in the urine than did those with prostate cancer without metastases, or healthy men of the same age (n = 35). Comparison of the results of hydroxyproline determination with the other diagnostic methods for demonstrating bone metastases showed that hydroxyproline determination was diagnostically on par with the scintigram. Pelvic crest biopsy, pelvic and sternal marrow aspiration can be considered valuable supplementary diagnostic procedures.

Bone Neoplasms↗
PubMed1978

Therapeutic effect of dexamethasone in experimental head injuries.

Experimental head injuries, which are easily reproducible in animal studies with guinea pigs, result in a significant increase of secondary serum enzymes. Malate dehydrogenase (MDH), fructose 1,6-diphosphate-aldolase and lactate dehydrogenase (LDH), together with the isoenzymes 1 and 2, are found especially in brain in large amounts. These enzymes act as 'tracer substances' of cerebral tissue and show significantly increased serum activities in cases where acute substantial damage to the brain associated with severe alterations of the blood-brain barrier is found. In the absence of shock, hypoxia and additional bodily injuries the loss of brain tissue has to be considered the only source of enzyme outflow. The early treatment of injured animals with high doses of dexamethasone results in a protective and stabilizing effect, preventing the extrusion of enzymes from the traumatically involved brain cells. Thus by observing the characteristic serum enzyme activities of treated and untreated injured animals a therapeutic effect of dexamethasone can be demonstrated within a relatively short time.

Animals↗
PubMed1978

[The protective effect of magnesium-aspartate-procaine cardioplegia on the hypertrophied left ventricle of the mini-pig (author's transl)].

After induction of left ventricular hypertrophy by supravalvar constriction of the ascending aorta in mini pigs (ATP and lactate) were measured under different cardioplegic conditions. In normothermia and plain anoxic arrest ATP decrease and lactate increase were significantly slower in hypertrophied myocardium compared to normal myocardium. Injection cardioplegia using magnesium-aspartate-procaine at 37 degrees C did not influence the ATP decrease and lactate increase in the hypertrophied ventricle, whereas in the normal heart it showed some protection according to these parameters. Optimal ATP preservation and the lowest lactate increase rate were achieved in left ventricular hypertrophy by combined application of magnesium-aspartate-procaine and hypothermia of 25 degrees C. We conclude that normothermic injection cardioplegia has no protective effect on the hypertrophied left ventricle, whereas additional hypothermia can improve magnesium-aspartate-procaine cardioplegia significantly.

Adenosine Triphosphate↗
PubMed1978

[Behaviour of ATP and lactate in human papillary muscle during profound hypothermia and injection cardioplegia with magnesium-asparatate-procaine (author's transl)].

In 53 patients with mitral- or aortic-mitral valve disease, the content of ATP and lactate of the papillary muscles resected at the time of valve replacement was investigated at the beginning of ischemic arrest and at the time of reperfusion. Profound body hypothermia (25 degrees C) and injection cardioplegia using magnesium-aspartate-procaine were applied for myocardial protection. In hypertrophic papillary muscles the myocardial ATP content decreased at a slower rate (ATP decay 12% of the initial value after 60 minutes of ischemia) than in normal papillary muscles obtained from patients with isolated mitral stenosis (ATP decay 33% of the initial value after 40 minutes of ischemia). 20% of the patients required temporary inotropic circulatory support postoperatively for 12 to 88 hours. The ATP content of the papillary muscles of these patients differed only little from those, in who no myocardial failure occurred. However the myocardial lactate levels were higher in patients in whom a low cardiac output state evolved.

Adenosine Triphosphate↗