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Biomedical subjects

E Roth

Publications and source records attributed to E Roth.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Overestimation of serum concentrations of gamma-aminobutyric acid in patients with hepatic encephalopathy by the gamma-aminobutyric acid-radioreceptor assay.

Sera of patients with hepatic encephalopathy strongly inhibit the specific binding of gamma-aminobutyric acid to synaptic membranes. In a previous study, this inhibition of specific gamma-aminobutyric acid binding was attributed to gamma-aminobutyric acid itself, and it was assumed that serum gamma-aminobutyric acid is increased 5- to 30-fold in patients with hepatic encephalopathy. The findings of that study, however, were not confirmed by other analytical methods. Therefore, the validity of the gamma-aminobutyric acid-radioreceptor assay was tested. In view of the increased serum concentrations of several amino acids in hepatic encephalopathy, the effects of L-alpha-amino acids on the assay were studied. Five amino acids inhibited specific gamma-aminobutyric acid binding at a concentration of 0.5 mM or lower: glutamine; glutamate; taurine; proline, and OH-proline. Equimolar amounts of aminooxyacetate prevented the inhibition of specific gamma-aminobutyric acid binding by glutamine and glutamate but had no effect on that of gamma-aminobutyric acid, taurine, proline and OH-proline. Aminooxyacetate had no effect on specific gamma-aminobutyric acid binding itself. The inhibitory activity of a serum sample from a patient with hepatic encephalopathy was inhibited by 0.5 mM aminooxyacetate. The gamma-aminobutyric acid binding inhibitory activity of a serum sample of a patient with hepatic encephalopathy was purified by gel chromatography and contained several amino acids at concentrations of about 0.1 mM, 3.5 mM glutamine but no detectable gamma-aminobutyric acid. Accordingly, the gamma-aminobutyric acid binding inhibitory activity is not mediated by gamma-aminobutyric acid alone and is most likely due to glutamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMedDate not supplied

Dynamism of NF-kappaB and AP-1 activation in the signal transduction of ischaemic myocardial preconditioning.

Nuclear factor (NF)-kappaB and activation protein (AP)-1 transcription factors play an important role in the signal transduction of delayed ischaemic preconditioning (PC) leading to myocardial cytoprotection. Because the exact mechanism of the activation of these factors is still not clear, we aimed to monitor the time fluctuation of NF-kappaB and AP-1 induction in an in vivo animal model. Furthermore, we measured the induction rate of these factors using repeated cycles of PC. Following median thoracotomy, anaesthetized animals (24 New Zealand White rabbits) were subjected to ischaemic PC by occlusion of the left anterior descending coronary artery for 5 min. After 10 and 30 min, and 1, 2, 3 and 4 h of reperfusion, tissue samples were taken from the ischaemic myocardium, and the DNA binding activity of the transcription factors was measured with electrophoretic mobility shift assay. A further 12 animals were subjected to 2 x, 3 x or 4 x 5-min ischaemic PC, and after a 30-min or 1-hour reperfusion period, we investigated the possible modulation of NF-kappaB and AP-1 induction. Our results show significant, biphasically increased NF-kappaB activity with peak levels at 30 min and 3 h of reperfusion in preconditioned myocardium. AP-1 increased monophasically, with the peak level at 1 h of reperfusion. Repeated PC stimuli enhanced the activity of both transcription factors analyzed, but there was no significant correlation between the number of cycles and the rate of activation. Our results show that the activation of NF-kappaB and AP-1 have a specific time curve, and the induction of these factors is only slightly influenced by the number of PC cycles.

Animals↗
PubMedDate not supplied

Kindergarten prevention of dyslexia: does training in phonological awareness work for everybody?

This study examined the effects of training in phonological awareness on kindergarten children. Comparisons of children at risk (i.e., children with initially low levels of metalinguistic ability) with initially average and advanced children revealed that training gains were similar for all of these groups. Furthermore, training had comparable long-term effects on reading and spelling in Grades 1 and 2 for each group. In fact, the trained children at risk showed better reading and spelling performance than a randomly selected control group. Although considerable individual differences in training effectiveness were found Within the group of at-risk children, there was clear evidence that the training program substantially reduced the risk of becoming dyslexic in school.

Age Factors↗
PubMedDate not supplied

Free amino acids in plasma and muscle in fulminant hepatic coma during an extracorporeal liver perfusion.

A 21-year-old female patient suffering from fulminant hepatic failure was treated with extracorporeal normothermic baboon's liver perfusion for 60 hours. The amino acids (AA) uptake of the extracorporeal organ and the ratio of plasma and muscle AA at the end of the perfusion were measured. The AA uptake of the extracorporeal liver was 414 millimoles per 60 hours and even greater during hemodialysis treatment. In spite of this AA uptake, the plasma AA pattern was not normalized. At the end of the perfusion, the free AA concentration in muscle tissue was 86.25 millimoles per liter of intracellular water, an increase of 62% compared to healthy volunteers. In the patient, the ratio of glutamine to glutamine in muscle tissue was 20 to 1 compared to 5 to 1 in normals. It is concluded that (1) the extracorporeal baboon liver cannot extract the quantities of AA released by endogenous protein catabolism in hepatic failure, and (2) the muscular ammonia detoxification system gets overloaded as indicated by the increase ratio of glutamine to glutamate.

Adult↗
PubMedDate not supplied

Effects of nutrition on plasma, liver and muscle amino acids in scalded rats.

This study set out to investigate the effect of three different parenterally administered diets on the free amino acid (AA) levels in the plasma, muscle, and liver of scalded rats. Diet I consisted of AA (1.4 g/100 g weight) and a high glucose dose (6 g/100 g weight), diet II consisted of AA and a low glucose dose (1.4 g/100 g weight) and in diet III only a low glucose dose was infused. Parenteral nutrition was started on the 3rd day posttraumatically. Sampling was performed on the 7th day posttraumatically. Nitrogen balances were significantly different in all three groups, being lowest in group III. Scalded rats fed isonitrogenously, but with different amounts of glucose showed only minor changes in AA concentrations. However scalded rats fed with a nitrogen-free diet exhibited significantly reduced total muscle and liver AA levels. These decreased AA levels were due to a drop of glycine in the muscle tissue (74%) and liver (49%). Contrary to the clinical catabolic situation in scalded and starved rats, it was not intracellular glutamine but glycine which was considerably influenced by catabolism and starvation.

Amino Acids↗
PubMedDate not supplied

Different transendothelial migration behaviour pattern of blood monocytes derived from patients with benign and malignant diseases of the breast.

BACKGROUND: In this study we compared the expression of selected monocyte surface antigens with the potential to transmigrate through an endothelial layer before and after surgery from breast cancer patients (CA) and patients with benign disease of the breast (BE). MATERIALS AND METHODS: Transmigration capacity of mononuclear cells was determined after isolation by Ficoll density gradient, layered over human umbilical vein endothelial cells and cultured in a two chamber plate added with fMLP as a chemotactic stimulus. We determined monocyte phenotye (HLA-DR, FcgRI/CD64, CR1/CD11b and LFA-1/CD11a) and the phagocytosis of E. coli by flow cytometry. RESULTS: Before surgery blood monocytes had an equal expression of the measured surface antigens, but were different in regard to their interaction with endothelial cells. Monocytes derived from CA had a higher transmigration potency than those of BE. Moreover, the migration through the endothelial cell layer created different populations of monocytes. Surgical stress modified transmigrated monocytes of BE into the direction of monocytes from CA. Phagocytic capacity of peripheral blood monocytes from CA was significantly diminished and was further reduced after surgery when measured in transmigrated cells. CONCLUSION: Our study shows that monocytes from CA and BE can be discriminated in regard to their interaction with endothelial cells.

Adult↗
PubMedDate not supplied

Is peripheral blood a reliable indicator of acute oxidative stress following heart ischemia and reperfusion?

BACKGROUND: Reactive oxygen species (ROS) play a crucial role in membrane damage in ischemic-reperfusion syndromes. The aim of our work was to determine whether blood samples taken from a peripheral vein are a reliable indicator to reflect the development of oxidative stress following acute heart ischemia and reperfusion. MATERIAL AND METHODS: In a dog model, the left descending coronary artery (LAD) was occluded for 60 min followed by 60 minutes of reperfusion. The lipid peroxidation marker malondialdehyde (MDA), endogenous antioxidants reduced glutathione (GSH), the activity of superoxide dismutase (SOD) enzyme and the stimulated radical production of isolated neutrophil granulocytes (PMN) were measured simultaneously from the peripheral vein and the coronary sinus before and at the end of the LAD occlusion, and again during reperfusion. RESULTS: MDA and SOD values increased during reperfusion. At the end of 1 hour the reperfusion changes in the coronary sinus were significant (p<0.05). GSH increased in the femoral vein, but decreased in the coronary sinus. The radical-producing capacity of PMNs decreased by the end of LAD occlusion, and a further significant decrease was measured during reperfusion in the coronary sinus (p<0.01). In the peripheral venous blood samples the decrease of PMN radical production became significant only at 30 minutes of reperfusion (p<0.02), and the earlier difference between the coronary sinus and the femoral vein tended to level out following 60 minutes of reperfusion. CONCLUSIONS: During early reperfusion following myocardial ischemia coronary sinus blood sampling gives an earlier indication of myocardial damage. At a later phase, peripheral blood samples may also be informative regarding the altered balance between ROS production and the antioxidant capacity.

Animals↗
PubMedDate not supplied

Spiperone-induced endothelium-dependent relaxation of porcine coronary artery: an investigation into the underlying mechanism.

In pig coronary artery rings contracted by the thromboxane analogue U 46619 (9,11-dideoxy-11 alpha, 9 alpha-epoxy-methano-prostaglandin F 2 alpha), spiperone induced a relaxation which, at 30 mumol/l, corresponded to a complete reversal of the U 46619-induced contraction. The concentration-response curve for spiperone was bell-shaped. The second phase, i.e. the reduction of the relaxant effect (at concentrations above 30 mumol/l) was due to a contractile effect which was the only response in (1) endothelium-denuded arteries, (2) arteries treated with gossypol or methylene blue, or (3) arteries not precontracted with U 46619. Suramin and reactive blue 2 antagonized the relaxing effect, whereas metitepine, spiroxatrine, propranolol, idazoxan, flupenthixol, atropine and 8-phenyltheophylline did not. The endothelium-independent contraction was not reduced by metitepine. In strips of arteries with intact endothelium, incubated with [3H]adenosine and subsequently superfused with physiological salt solution containing dipyridamole, spiperone evoked an increase in tritium overflow above basal efflux. The present results are compatible with the hypothesis that spiperone releases ATP from the pig coronary artery. ATP, in turn, seems to activate endothelial P2 purinoceptors, leading to the release of endothelium-derived relaxing factor (NO) with a subsequent vascular relaxation.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗