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Biomedical subjects

W Kreisel

Publications and source records attributed to W Kreisel.

44 records · Page 3Linked to original sources
PubMed1984

Modification of the intramolecular turnover of terminal carbohydrates of dipeptidylaminopeptidase IV isolated from rat-liver plasma membrane during liver regeneration.

An intramolecular turnover of the terminal carbohydrates L-fucose, N-acetylneuraminic acid and D-galactose is a characteristic property of several liver plasma membrane glycoproteins, first demonstrated for dipeptidylaminopeptidase IV (EC 3.4.14.5., DPP IV). The core carbohydrates D-mannose and N-acetyl-D-glucosamine turn over like the polypeptide chain. The ratio of apparent half-lives of L-fucose and L-methionine of DPP IV is shifted from 0.17 in normal liver to 0.60 in regenerating liver. The ratio of half-lives of N-acetylneuraminic acid and L-methionine is only slightly changed from 0.43 in normal liver to 0.61 in regenerating liver. The ratio of apparent half-lives of D-mannose and L-methionine amounts to 0.80 in normal liver and 0.71 after partial hepatectomy. From this a drastic reduction of the intramolecular turnover of L-fucose on plasma membrane DPP IV in regenerating liver can be derived. The intramolecular N-acetylneuraminic acid turnover is affected to only a minor extent. D-Mannose turns over like the polypeptide in both normal and regenerating liver. The intramolecular L-fucose turnover may be involved in membrane glycoprotein recycling, which presumably is altered in regenerating liver. Additionally, L-fucose could regulate the rate of degradation of DPP IV, since core-fucosylated glycoproteins appear to be resistant to mammalian endo-N-acetylglucosaminidase.

Animals↗
PubMed1983

Heterogeneous turnover of terminal and core sugars within the carbohydrate chain of dipeptidylaminopeptidase IV isolated from rat liver plasma membrane.

Dipeptidylaminopeptidase IV, a plasma membrane-bound glycoprotein, is characterized by an intramolecular heterogeneous turnover of the protein backbone and carbohydrate chain. The faster turnover of the latter is restricted only to the outer sugars. The inner core sugars D-mannose and N-acetyl-D-glucosamine turn over at the same rate as the protein backbone.

Animals↗
PubMed1980

Different half-lives of the carbohydrate and protein moieties of a 110,000-dalton glycoprotein isolated from plasma membranes of rat liver.

By using a four-step procedure (i, solubilization with Triton X-100; ii, affinity chromatography on concanavalin A-Sepharose; iii, affinity chromatography on wheat germ lectin-Sepharose; iv, preparative sodium dodecyl sulfate gel electrophoresis) a glycoprotein was isolated from rat liver plasma membrane. The molecular weight is 110,000 and the isoelectric point is 5.8. It contains L-fucose, N-acetylneuraminic acid, D-galactose, D-mannose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and considerable quantities of aspartate, threonine, serine, and leucine. In pulse-chase experiments the half-lives of methionine and arginine, representing the half-life of the protein, were determined as 70 hr and 78 hr, respectively. The half-lives of the terminal carbohydrates L-fucose and N-acetylneuraminic acid were 12.5 and 33 hr, respectively. The galactose half-life was 20 hr. From this it is concluded that terminal sugars turn over several times in the life-span of this protein molecule. This process may be operative during membrane recycling mechanisms.

Animals↗
PubMedDate not supplied

Therapy of invasive aspergillosis with itraconazole: improvement of therapeutic efficacy by early diagnosis.

We report on the treatment of invasive aspergillosis with the new triazole antimycotic agent itraconazole. All 11 patients suffered from pulmonary invasive aspergillosis. Two patients also had cerebral aspergillosis; in one of these patients the paranasal sinuses were also invaded. Underlying diseases were acute lymphoblastic leukaemia (n = 3), acute myeloid leukaemia (n = 4); one patient underwent allogeneic bone marrow transplantation before he developed aspergillosis; another was transplanted after successful aspergillosis treatment, liver cirrhosis (n = 1), lung infarction after pulmonary embolism (n = 1), chronic bronchitis after pulmonary tuberculosis (n = 1) and AIDS (n = 1). In five cases initial diagnosis was established by means of mycological methods and clinical signs. In six patients invasive pulmonary aspergillosis was initially diagnosed due to the clinical criteria presented in this paper. Secondary mycological confirmation after onset of therapy was achieved in five out of these six patients. All of the patients initially responded to therapy. One female patient experienced a relapse of aspergillosis and died of cerebral involvement and relapsing leukaemia. Two further patients died due to underlying diseases (pulmonary embolism, relapsing leukaemia). Nine patients (82%) were cured of the mycosis, including the patient with cerebral involvement; two underwent surgical resection of residual pulmonary lesions. Itraconazole is a very effective drug for treatment of invasive aspergillosis. Therapeutic efficacy can be optimized by early diagnosis using clinical criteria and prompt start of treatment.

Adult↗