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Biomedical subjects

H Kowalewski

Publications and source records attributed to H Kowalewski.

5 recordsLinked to original sources
PubMed1993

Isolation of a Ca2+ or Mg(2+)-activated ATPase (ecto-ATPase) from bovine brain synaptic membranes.

An ATPase was isolated from synaptosomal plasma membranes derived from bovine cerebral cortex. The protein has an apparent molecular mass of 50 kDa and a pI of 5.3 to 5.9. It can be labelled by incubation of intact synaptosomes with azido-GTP or azido-ATP. The isolated ATPase can be activated to a similar extent in the presence of millimolar concentrations of Mg2+ or Ca2+. It does not hydrolyze ADP. Maximal activity is obtained between pH 7.5 and 8.5. Typical inhibitors of cytoplasmic ATPases do not affect enzyme activity. The enzyme is specifically inhibited after previous incubation of intact synaptosomes in the presence of the slowly membrane-permeable enzyme inhibitor diazotized sulfanilic acid. Incubation of intact synaptosomes with diazotized sulfanilic acid results in a small increase in the apparent molecular mass of the enzyme. Our results suggest that the active site of the membrane bound enzyme faces the extracellular medium. It thus would represent an ecto-ATPase.

Adenosine Triphosphatases↗
PubMed1992

Soluble low-Km 5'-nucleotidase from electric-ray (Torpedo marmorata) electric organ and bovine cerebral cortex is derived from the glycosyl-phosphatidylinositol-anchored ectoenzyme by phospholipase C cleavage.

Soluble and membrane-bound low-Km 5'-nucleotidase was isolated from high-speed supernatants and membrane fractions derived from the electric organ of the electric ray (Torpedo marmorata) or from bovine brain cerebral cortex. Purification of both enzymes included chromatography on concanavalin A-Sepharose and AMP-Sepharose. The contribution to the total of soluble enzyme activity was lower in electric organ (1.6%) than in bovine cerebral cortex (27.9%). Membrane-bound and soluble forms have very similar Km values for AMP and are inhibited by micromolar concentrations of ATP. Both forms cross-react with, and are inhibited by, an antibody against the membrane-bound surface-located (ecto-) 5'-nucleotidase from electric organ. The HNK-1 carbohydrate epitope is present on both forms of the Torpedo enzyme, but is entirely absent from bovine cerebral-cortex 5'-nucleotidase. An antibody specific for the inositol 1,2-(cyclic)monophosphate that is formed on phospholipase C cleavage of an intact glycosyl-phosphatidylinositol (GPI) anchor binds to the soluble, but not to the membrane-bound, form of the enzyme from both sources. Our results suggest that soluble low-Km 5'-nucleotidase in both electric organ and bovine brain is derived from the membrane-bound GPI-anchored form of the enzyme by the action of a phospholipase C and is not a soluble cytoplasmic enzyme.

5'-Nucleotidase↗
PubMed1990

[Body-packer syndrome. Psychotropic drug smuggle in the human body--discussion from the legal and medical viewpoint based on own patients].

Body packing is the term used to describe the smuggling of drugs, usually cocaine or heroin, in special containers introduced within the body. Rupture of the containers leads to acute intoxication that often ends fatally. The possibility of drug poisoning should always be considered by the emergency or hospital physician confronted with an unconscious patient. If representatives of the law suspect anyone of drug smuggling and refer him/her to hospital, a knowledge of the legal position as laid down in particular in paragraph 81a and d of the StPO is of great importance.

Cocaine↗
PubMed1989

[The "upside-down stomach"--a diagnostic pitfall].

Upside down stomach is an extreme variant of a paraesophageal hernia. The cardia and pylorus are located next to each other, while the rest of the stomach lies within the thorax. Radiology is mandatory for accurate anatomical documentation, while endoscopy is necessary to identify pathology, primarily bleeding sources. This is a rare condition found during endoscopy, with an incidence of 1.5%. Since there is a risk of volvulus, surgical correction is usually indicated.

Diagnosis, Differential↗