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Biomedical subjects

B Pohl

Publications and source records attributed to B Pohl.

43 records · Page 3Linked to original sources
PubMed1978

The brush border of rabbit kidney, a cellular compartment free of glycolytic enzymes.

Activities of four enzymes of the glycolytic pathway, hexokinase, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase, were determined in a vesicular brush-border preparation from rabbit kidneys. The specific activities of the enzymes were decreased several-hundredfold in the brush-border preparation compared with a kidney homogenate, but the enzymes were not totally absent. Density-gradient centrifugation of the brush-border preparation yielded brush border of even higher purity and also a characteristic pattern of distribution for each of the contaminating intracellular membranes. The presence of hexokinase in the brush-border preparation could be traced to contaminating mitochondria, and that of glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase to contaminating vesicles derived from the endoplasmic reticulum. The brush-border vesicles contained some ATP. An intravesicular concentration of 0.1mm was estimated, indicating that the vesicles had retained at least a part of their original content. Experiments in which fluorescein isothiocyanate-dextran (mol.wt. 20000) was present during cell lysis revealed that much, but not all, of the brush-border contents had been exchanged with the medium. The complete absence of glycolytic enzymes from brush-border vesicles, which had retained part of their original content, indicates that the brush border does not contain glycolytic enzymes in vivo and can be thought of as a compartment of its own, somehow separated from the cytoplasm.

Adenosine Triphosphate↗
PubMedDate not supplied

[Free amino acids in the saliva of children with phenylketonuria].

UNLABELLED: Free amino acids were determined quantitatively in saliva of 23 children with phenylketonuria (male = 11, female = 12) (ages 6-17 years). Saliva was deproteinised by adding an equal volume of 5% sulphosalicylic acid and the amino acids were separated by ion exchange column chromatography. RESULTS: The comparison of the amino acid concentrations in saliva of phenylketonuric children with healthy children (male = 34, female = 31) (ages 6-13 years) showed, that vast majority of amino acids - taurine, serine, glutamine, glycine, alanine, citrulline, a-aminobutyric acid, valine, isoleucine, leucine, tyrosine, phenylalanine, ornithine, lysine, delta-aminovaleric acid - were excreted significantly lower in saliva of phenylketonuric children.

Adolescent↗
PubMedDate not supplied

The quick machine--a mathematical model for the extrinsic activation of coagulation.

The present paper describes a mathematical model of the kinetics of the extrinsic coagulation cascade in vitro. The coagulation factors FI, FII, FV, FVII, FX, heparin and antithrombin III (ATIII) as well as soluble fibrin polymers are considered. The effect of single-factor deficiencies of the factors II, V, VII and X, diseases like hypo- and dysfibrinogenaemia, hepatic insufficiency, inhibited polymerisation by degradation products, heparin therapy with and without ATIII deficiency and coumarin therapy on prothrombin time can be portrayed. Physiology of coagulation is represented in a dynamic mathematical model as a differential equation system. The model is based on three reaction types: enzymatic cleavage, complex formation and polymerisation. The model was implemented in a continuous simulation program on a personal computer using the Pascal programming language. Unknown rate constants were estimated by chi 2 fit. Prothrombin time calculated by the model was compared to the training set of 20 plasma samples. In most but not all cases the model harmonized quite well with the coagulometric data.

Blood Coagulation↗