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Biomedical subjects

H Kunze

Publications and source records attributed to H Kunze.

At least 73 records · Page 4Linked to original sources
PubMed1986

Diacylglycerol hydrolysis in rat liver lysosomes.

The matrix of rat liver lysosomes exhibits high hydrolytic activity towards 1,2-diacylglycerol with an optimum at pH 4.0. The lipolytic reaction follows Michaelis-Menten kinetics (apparent Vmax 470 nmol hydrolysed/min per mg protein; apparent Km 71 microM 1,2-dioleoylglycerol). Formation of 1- and 2-monooleoylglycerols indicates an initial attack at both the primary and secondary ester bonds. The lysosomal matrix also catalyses (re)acylation reactions, i.e. the formation of 1,2-diacylglycerol from 2-monoacylglycerol and free fatty acid. However, (re)acylation proceeds at a far lower rate than deacylation of diacylglycerol. Lysosomal diacylglycerol hydrolysis is sensitive towards non-ionic detergents, cationic amphiphilic drugs and the lipase inhibitor RHC 80267.

Acid Phosphatase↗
PubMed1985

Synthesis of covalently immobilized phospholipid analogues.

Cyclic 1-O-acyl-2-O-alkyl-glycero-3-phosphotriesters and 1-O-acyl-2-O-alkyl-glycero-3-bromoethylphosphate with a free acyl moiety in position 1 of the glycerol backbone were synthesized. These phospholipid intermediates were covalently bound to AH-Sepharose via the carbodiimide method. After immobilization the corresponding phosphatidylethanolamine analogues were obtained by acid hydrolysis of the cyclic phosphotriesters and by direct amination of the bromoethylphosphate. Thus, in a short, stepwise synthesis including minimum use of protecting groups, a variety of immobilized phospholipid analogues are available as affinity adsorbents for the purification of enzymes related to phospholipid metabolism.

Indicators and Reagents↗
PubMed1985

Effects of antimalarial drugs on phospholipase A and lysophospholipase activities in plasma membrane, mitochondrial, microsomal and cytosolic subcellular fractions of rat liver.

Activities of membrane-associated phospholipases A1 and A2, and membrane-associated as well as soluble lysophospholipases were measured in different subcellular fractions of rat liver, using suspensions of stereospecifically labelled radioactive phospholipids as substrates. Plasma membranes and endoplasmic reticulum were shown to contain phospholipase A1 and lysophospholipase activities, both of which could be stimulated by Ca2+, mitochondria Ca2+-dependent phospholipase A2 and cytosol Ca2+-independent lysophospholipase activities. Each of these lipolytic enzymes could be inhibited by antimalarial drugs (chloroquine, mepacrine, primaquine) at concentrations above 1 x 10(-4) M. Inhibition of the alkaline cytosolic lysophospholipase by these drugs was noncompetitive with respect to the substrate, and the inhibitory potency increased, when the pH was raised.

Animals↗
PubMed1985

Purification and properties of phospholipase A2 from human seminal plasma.

The soluble Ca2+-dependent phospholipase A2 (EC 3.1.1.4) was purified 6500-fold with a yield of about 20% from human seminal plasma. The successive purification steps comprised gel filtration, affinity chromatographies and micropartition. The final preparation consisted of two proteins in about equal quantities with molecular weights of 12000 and 14000, according to SDS-polyacrylamide slab gel electrophoresis. As yet these two proteins can not be separated without complete loss of activity. Apparent kinetic parameters have been determined for the purified preparation with different substrates (Vmax = 494 U/mg, and Km = 1.25 X 10(-4) M long-chain phosphatidylethanolamine; Vmax = 7.4 U/mg, and Km = 2.5 X 10(-5) M long-chain phosphatidylcholine; Vmax = 7196 U/mg and Km = 8.32 X 10(-4) M dioctanoylphosphatidylcholine). The enzymatic activity was not affected by diisopropylfluorophosphate and thiol reagents but it was inhibited by higher concentrations of nonionic and ionic (except taurocholate) detergents and by the alkylating reagent p-bromophenacyl bromide. Although the seminal enzyme functionally strongly resembles the pancreatic phospholipase A2, no immunochemical relationship was observed; anti-pancreatic phospholipase A2 IgGs did not inhibit seminal phospholipase A2. Similarly, partially purified phospholipase A2 from horse seminal fluid was not affected by antibodies raised against horse pancreatic phospholipase A2.

Chromatography↗
PubMed1985

Rehabilitation and institutionalisation in community care in West Germany.

This study examines the quality of residential care in non-psychiatric nursing homes and psychiatric group homes for a representative epidemiologically-based sample of patients discharged from a psychiatric hospital in West Germany. There were twice as many chronically ill patients in sheltered accommodation as in hospital, 85% of them in nursing homes, which scored badly on all measures of therapeutic environment. This poverty of social environment was correlated with severity of symptoms for schizophrenics, especially with flatness of affect and poverty of speech. Nursing homes were just as likely as hospitals to promote chronic illness and hinder rehabilitation.

Adult↗
PubMed1984

A combined assay of three lysosomal marker enzymes: acid phosphatase, beta-D-glucuronidase, and beta-N-acetyl-D-hexosaminidase.

A simplified and rapid method for simultaneous activity measurements of three lysosomal marker enzymes, acid phosphatase, beta-glucuronidase, and beta-N-acetyl-D-hexosaminidase is described. The incubation is carried out in a single test tube and stopped by adding an alkaline sodium dodecyl sulfate solution, thus avoiding centrifugations and allowing for higher Triton X-100 concentrations in the incubation media. Two products of the beta-glycosidases (phenolphthalein and 2-nitrophenolate) are measured spectrophotometrically at the respective wavelengths (555 and 420 nm), and one of the acid phosphatase products is quantitatively determined by measuring inorganic phosphate.

Acid Phosphatase↗
PubMed1984

Influence of the anti-inflammatory serine esterase inhibitor gabexate mesilate (Foy) on aggregation, locomotion and adhesion of polymorphonuclear leukocytes.

The effects of the anti-inflammatory serine esterase inhibitor, gabexate mesilate (Foy) were studied, on locomotion, autoaggregation and adhesion of polymorphonuclear leukocytes stimulated with the complement peptide C5a-desArg. The drug inhibited aggregation as well as spontaneous and directed migration of human leukocytes at concentrations of about 10(-3) M. Adhesion of peritoneal guinea-pig leukocytes to autologous aortic strips was reduced at about 20 times lower drug concentrations. The inhibitory drug effects were highly time- and temperature-dependent. Experiments with the two major drug metabolites, pHB and epsilon GC, indicate that gabexate mesilate is not active by itself but rather by its hydrolytic aromatic metabolite pHB. The results further suggest that the inhibitory effects on leukocyte activities observed are not related to the anti-inflammatory effects of gabexate mesilate.

Animals↗
PubMed1984

Effects of the serine protease inhibitor gabexate mesilate on purified pancreatic phospholipase A2.

The catalytic activity of purified porcine pancreatic phospholipase A2 is competitively inhibited by the cationic amphiphilic serine protease inhibitor gabexate mesilate (ethyl 4-(6-guanidinohexanoyloxy) benzoate methanesulfonate). A Ki of 1.3 X 10(-4)M was found when 1,2-dioctanoyl-sn-glycero-3-phosphorylcholine was used as a substrate. The main metabolites of this drug, 6-guanidinocaproic acid and ethyl p-hydroxy-benzoate, had no effect in concentrations up to 10(-2)M. From the high gabexate mesilate concentrations required to reduce phospholipase A2 activity and from the considerably lower drug concentrations sufficient to cause beneficial effects in acute pancreatitis it is concluded that direct inhibition of pancreatic phospholipase A2 cannot be the cause of the therapeutic results, improvement of the symptoms and prognosis of acute pancreatitis.

Animals↗
PubMed1983

Effects of the serine protease inhibitors FOY and FOY 305 on phospholipase A1 (EC 3.1.1.32) activity in rat - liver lysosomes.

Rat-liver lysosomal phospholipase A1 activity is unspecifically inhibited in a pH dependent and competitive manner by the cationic amphiphilic protease inhibitors FOY (ethyl 4-6(6-guanidinohexanoyloxy) benzoate methanesulfonate) and FOY 305 (N,N-dimethylcarbamoylmethyl 4-(4-guanidinobenzoyloxy)-phenylacetate methanesulfonate) in concentrations above 10(-4)M. This inhibition may contribute to anti-inflammatory effects of these drugs in that they reduce the release by lysosomal enzymes of fatty acids from membrane phospholipids and consequently decrease the biosynthesis of bioactive oxygenated arachidonate metabolites, among them inflammatory mediators.

Animals↗
PubMed1983

Effects of the anti-inflammatory serine esterase inhibitor, FOY, on phospholipase A2 (EC 3.1.1.4) activity in rabbit polymorphonuclear leukocytes.

Phospholipase A2 activity of polymorphonuclear leukocytes (PMNLs) towards radioactively labelled phosphatidylethanolamine is inhibited by FOY (ethyl 4-(6-guanidinohexanoyloxy)-benzoate methanesulfonate) in concentrations above 10(-4)M. The inhibition is noncompetitive with respect to the substrate employed and depends on the pH. Impairment of PMNL phospholipase A2 activity could play a role in the anti-inflammatory effect of FOY: the release of fatty acids from membrane phospholipids is reduced and consequently also the biosynthesis of bioactive oxygenated arachidonate metabolites, among them inflammatory mediators.

Animals↗
PubMed1983

Does PGE2 have a beneficial effect on acute experimental pancreatitis in the rat?

Prostaglandin E2 (PGE2) is known to have a cytoprotective effect on the gastric mucosa exposed to a variety of noxious agents. A cytoprotective effect on the pancreas in acute pancreatitis has been postulated, but available evidence is contradictory. Acute experimental pancreatitis was induced in 170 male Wistar rats by retrograde injection of 0.6 ml of 5% Na-taurocholate into the pancreatic duct. PGE2 (0.1 microgram/g rat) was given intraductally, intraperitoneally or subcutaneously before and after induction of pancreatitis. PGE2 had no effect on survival rate, enzyme levels in serum and ascites, or on morphologic damage to the pancreas.

Acute Disease↗
PubMed1982

Effects of antimalarial drugs on several rat-liver lysosomal enzymes involved in phosphatidylethanolamine catabolism.

The effects of three cationic amphiphilic antimalarial drugs (chloroquine, mepacrine and primaquine) on the intralysosomal catabolism of phosphatidylethanolamine and several of its metabolites were studied with rat-liver lysosomes which had been isolated from animals previously treated with Triton WR-1339. The activities of each of the various enzymes involved in the main pathways of intralysosomal phosphatidylethanolamine degradation (Kunze, H., Hesse, B. and Bohn, E. (1982) Biochim. Biophys. Acta 711, 10-18) exhibited almost identical inhibitory sensitivities towards mepacrine and primaquine. In contrast, chloroquine inhibited the activities of the various enzymes to different extents, lysophospholipid acylhydrolase (EC 3.1.1.5) being the most sensitive enzyme, followed by phospholipase A1 (EC 3.1.1.32) and monoacylglycerol lipase, and eventually lysophospholipid monoacylglycerol hydrolase as the least sensitive enzyme. The relative inhibitory potencies towards phospholipase A1 activity of chloroquine were increased with increasing pH, and the mode of inhibition was competitive. In contrast, the inhibitory potencies towards monoacylglycerol lipase activity of chloroquine increased only up to pH 5 but decreased above this value, and the mode of inhibition was noncompetitive.

Animals↗
PubMed1982

Hydrolytic degradation of phosphatidylethanolamine and phosphatidylcholine by isolated rat-liver lysosomes.

Lysosomal catabolism of radioactively labelled phosphatidylethanolamine, phosphatidylcholine and several potential metabolites of these diacylphospholipids was studied using rat-liver lysosomes which had been isolated from Triton WR-1339-treated animals. Hydrolysis of these lipids seems to be restricted to the soluble lysosomal compartment. The initial intralysosomal degradation is predominantly catalysed by phospholipase A1 (EC 3.1.1.32) followed by lysophospholipase (EC 3.1.1.5). The end products of this pathway are free fatty acids and glycerophosphorylethanolamine or glycerophosphorylcholine. These phosphodiesters are not hydrolysed further in lysosomes, as has been shown previously (Fowler, S. and De Duve, C. (1969) J. Biol. Chem. 144, 471-481). The intermediary lysophospholipids, however, are also hydrolysed by an alternative pathway, i.e. by a lysophospholipase which catalyses the hydrolysis of the glycerophosphate ester bond, followed by a monoacylglycerol lipase and a phosphomonoesterase (EC 3.1.3.2), respectively. Besides these two catabolic routes of intralysosomal hydrolysis of phosphatidylethanolamine and phosphatidylcholine, additional pathways are possible, which seem, however, to be of minor importance, at least in the substrate concentration ranges employed in these studies. These additional reactions include attack by a phospholipase A2 (EC 3.1.1.4) and--as discovered recently (Matsuzawa, Y. and Hostetler, K.Y. (1980) J. Biol. Chem. 255, 646-652)--by a phospholipase C (EC 3.1.4.3). Cations such as Mg2+, Ca2+, K+ and Na+ inhibit preferentially deacylation reactions.

Animals↗
PubMed1982

[The mentally ill and disabled-stepchildren of rehabilitation].

The institutions traditionally catering for the mentally ill and disabled are more and more turning into Psychiatric Hospitals (Clinification). Efforts are being concentrated on treatment and therapy, while a majority of the chronically ill and disabled are placed in nursing homes for their long-term care (and are pensioned prematurely). Though an extensive network of rehabilitation facilities has been developed in the Federal Republic of Germany, and although social legislation has provided for equal status of the mentally ill and disabled with other ill or disabled persons, only a negligibly small number of patients from psychiatric facilities are given the opportunity for participating in rehabilitative measures. This arises from the fact that the present range of facilities has in the fist line been developed according to the rehabilitational needs of people with physical disability, and from a reluctance on the part of the agencies financially responsible for rehabilitation services and benefits (with the exception of social welfare) to honour this social legislative title of their mentally ill or disabled insured (except for patients with dependence problems and neuroses). As the official disability statistics, too, usually negate the specificity of mental illness and disability the problematic issue does not emerge openly.

Persons with Disabilities↗