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Biomedical subjects

M Hauck

Publications and source records attributed to M Hauck.

At least 37 records · Page 2Linked to original sources
PubMed1991

Human aortic elastin from normal individuals and atherosclerotic patients: lipid and cation contents; susceptibility to elastolysis.

Aortic elastins, isolated from 30 humans of different ages, were purified by alkaline extraction, and separated into two groups depending on the presence of atherosclerotic plaques and calcification (grades 0 and 1). It was confirmed that the severity of atherosclerosis increases significantly with age (P less than 0.001) and elastin content decreases with atherosclerosis (P less than 0.001). The hydrolysis of the aortic elastins using pancreatic porcine elastase (PPE) was studied. It was observed that increased elastolytic activities are connected with severity of atherosclerosis (P less than 0.001) and both Vm and Km apparent kinetic parameters are affected (P less than 0.001). Correlation tests have shown that enzymatic hydrolysis is significantly modified by cholesterol (P less than 0.05), calcium (P less than 0.001) and magnesium concentrations (P less than 0.01) but only cholesterol changes significantly Vm and Km parameters.

Adolescent↗
PubMed1989

O-specific polysaccharides of Hafnia alvei lipopolysaccharides isolated from two serologically related strains: ATCC 13337 and 1187. A serological and structural study using chemical methods, gas chromatography/mass spectrometry and NMR spectroscopy at 500 MHz.

The O-specific polysaccharides of Hafnia alvei ATCC 13337 standard strain and 1187 strain have been isolated and characterized. By means of 1H-NMR spectroscopy, methylation analysis and periodate oxidation, the repeating unit of the polysaccharides could be allocated the respective structures. (formula; see text) where Acyl = D-3-hydroxybutyryl, and 3-O-acetylation was to about 66%. The structural similarity of the polysaccharides was confirmed in the serological study; their epitopes were determined and the importance of various structural elements for the serological specificity was discussed.

Carbohydrate Conformation↗
PubMed1988

Structure elucidation of the core regions from Citrobacter O4 and O36 lipopolysaccharides by chemical and enzymatic methods, gas chromatography/mass spectrometry, and NMR spectroscopy at 500 MHz.

Novel enterobacterial core oligosaccharides were isolated from Citrobacter O4 and O36 lipopolysaccharides, and their structures were determined by methylation analysis, Smith degradation and enzymatic degradations, gas chromatography/mass spectrometry, and two-dimensional phase-sensitive correlated, relayed coherence transfer, double-quantum, triple-quantum-filtered, and nuclear Overhauser effect (NOE) 1H NMR spectroscopy at 500 MHz. In the formulas, all hexose residues are D-hexopyranoses, and heptoses are L-glycero-D-manno-heptopyranoses; the alternative locations of the side-chain heptose and pyrophosphorylethanolamine (PPEtN) residues are marked by dashed lines; dOclA stands for 3-deoxy-D-manno-octulosonic acid. (formula; see text) Along with these complete cores, incomplete ones, lacking the hexosamine trisaccharides, occur in the lipopolysaccharides of both types. Qualitative NOE data were in good agreement with the minimum energy conformation of the above O36 oligosaccharide, calculated with the aid of the SUGAR program [Sundin, A., Carter, R. E., & Liljefors, T. (1988) J. Mol. Graphics (in press)].

Acetylglucosaminidase↗
PubMed1988

[A new HPLC procedure for cyclamate in food with pre-chromatographic derivatization].

A high-pressure liquid chromatography (HPLC) procedure for the detection of cyclamate in liquid and solid samples is presented, which depends on oxidation and the reaction of cyclohexylamine with o-phthaldialdehyde to form a condensation product. The results of the HPLC analysis, using an RP-C 18 separation system with UV detection at 242 nm are reported. Contents, from 2 to 400 mg/l, can be detected in less than 2 h (HPLC analysis within 20 min) with relative standard deviations of 4%. Only for cucumber infusions were incomplete recoveries of 68% obtained.

Chromatography, High Pressure Liquid↗
PubMed1987

The application of 1H/13C inversely correlated NMR spectroscopy to the determination of acylation and glycosylation sites in the O-specific polysaccharide from Hafnia alvei 1187.

An inversely correlated 1H/13C NMR spectrum defined the amino sugars acylated by acetyl or 3-hydroxybutyryl groups and revealed partial sequences and glycosylation sites in a tetrasaccharide repeating unit of the title polysaccharide, (----2DGlc alpha 1----3DGlcNAcyl alpha 1----4DGalNAc alpha 1----3DGalNAc beta 1----)n, where Acyl = 3-hydroxybutyryl.

Acylation↗
PubMed1987

Structure determination of the O-specific polysaccharides from Citrobacter O4- and O27-lipopolysaccharides by methylation analysis and one- and two-dimensional 1H-NMR spectroscopy.

Using sugar and methylation analyses, and one- and two-dimensional 1H-NMR spectroscopy at 500 MHz it was established that poly-beta-1,2-4-deoxy-D-arabinohexopyranose occurs as O-specific chains of lipopolysaccharides in Citrobacter serotypes O4, O27 and O36. Strong serological cross-reactivity between these serotypes is in full agreement with the chemical identity of their O-specific polysaccharides.

Chemical Phenomena↗
PubMed1987

Alterations of the FMLP-induced Ca2+ efflux from human monocytes with aging.

The Ca2+ with the calmodulin system plays a major role in the receptor-induced intracellular biochemical events. Thus, as in our previous studies, we found an altered postreceptorial coupling in the case of elderly, we were interested to elucidate the Ca2+ transport in the case of healthy young (less than 25 years) and aged (greater than 65 years) subjects. The chemotactic peptide FMLP was used for receptor stimulation. Our data show that both spontaneous and FMLP-triggered Ca2+ extrusion measured on monocyte monolayers is decreased with aging. The FMLP-triggered Ca2+ extrusion nevertheless did not occur through the TFP-sensitive pathway. These alterations of Ca2+ transport seem to indicate an impaired Ca2+-calmodulin function in monocytes with aging.

Adult↗
PubMed1987

Divergent effects of human lymphokine derived oligopeptides on PMNLs function of young and aged healthy subjects.

The effects of low molecular weight lymphokine-derived oligopeptides (LK-OPs) on PMNLs effector functions and receptor mediated biochemical events were studied in the case of healthy young and aged subjects. In the case of young subjects the low mol. wt. LK-OPs stimulated the Fc gamma receptor-mediated effector functions of PMNLs, whereas an inhibition was observed in PMNLs of the elderly (extracellular cytotoxicity and intracellular killing). The underlying biochemical events, induced by low mol. wt. LK-OPs stimulation, were also investigated. In PMNLs of young subjects the oxidative metabolism was stimulated (enhanced O2 consumption, O2 and H2O2 production) by low mol. wt. LK-OPs, while in elderly subjects it was inhibited. The cyclic nucleotides regulating the Fc gamma receptor mediated effector functions and the oxygen radicals formation showed an altered dynamic response under low mol. wt. LK-OPs stimulation with aging i.e. the cGMP level could not be changed at all. Our results suggest that low mol. wt. LK-OPs induced inhibition of Fc gamma receptor mediated effector functions with aging could be partly explained by an altered post receptorial coupling switch and as a consequence the lymphokines could not play their role of immunomodulators further impairing the altered immune response with aging.

Adult↗
PubMed1986

Bidirectional effect of met-enkephalin on macrophage effector functions.

Met-enkephalin (ME) exerts a bimodal effect on functional activities of rat peritoneal macrophages (PM); in a range of low concentration (10(-9)-10(-7)M) antibody dependent cellular cytotoxicity (ADCC) was markedly stimulated with a simultaneous decrease of Fc gamma receptor (Fc gamma R) medicated phagocytosis while the opposite was observed at 10(-6)-10(-5)M concentrations. Studying the possible underlying mechanism(s) the followings were recorded: (1) ME in all applied concentrations induced an early Na+ influx which was followed by a Ca2+ efflux in the range of low concentrations. In the range of high concentrations Na+ influx was accompanied by a Ca2+ influx. (2) ME at 10(-8) M concentration induced a rise in cGMP level with a plateau in the 60-120th min of incubation. This effect was prevented by 10(-5) M of naloxone. At 10(-6) M concentration a transient rise of cAMP level was recorded which was not affected by naloxone. (3) Verapamil in 10(-6) M abolished both the Ca2+ influx and the rise in cAMP level induced by 10(-6)-10(-5) M ME but not the rise in cGMP level induced by lower ME concentrations. (4) cAMP elevation by high ME concentrations was abolished by enkephalinase inhibitory puromycin. (5) PM-enkephalinase as assessed by the cleavage of fluorogenic substrate L-alanine beta naphthylamide (ABNA), was inhibited by 10(-6)-10(-5) M of ME. This inhibition was abolished by verapamil, but not affected by naloxone. In the range of low concentrations ME appears to act on specific delta opioid receptors and its action is positively coupled to guanylate cyclase. In relatively higher concentrations ME-action is not mediated by specific delta opioid receptors and it appears to involve Ca2+ influx, adenylate cyclase activation as well as the processing of hormone by PM-enkephalinase.

Adenylyl Cyclases↗
PubMed1984

Met-enkephalin induced alterations of macrophage functions.

Met-enkephalin /Met-enk/ was found to stimulate IgG2a-mediated antibody dependent cytotoxicity /ADCC/ of thioglycollate elicited rat peritoneal macrophages /PM/ through naloxone-sensitive opiate receptors in concentrations ranging from 10(-9) - 14(-7) M. Phagocytosis of IgG2a coated 51Cr-sheep red blood cell /SRBC/ was suppressed by M-enk in the same concentration range. In the same range of concentrations, M-enk was observed to induce a significant increase in the generation of luminol dependent chemiluminescence /LDCL/. The observed stimulation of ADCC was abolished by calmodulin inhibitor triflouroperazine /TFP/ in 10(-6) M concentration. The involvement of cyclic nucleotides in the M-enk induced functional alterations is indicated by finding cGMP accumulation to be augmented in M-enk treated PMs.

Animals↗
PubMed1984

Design and methods in a multi-center case-control interview study.

We conducted a case-control study in ten areas of the United States in which a total of 2,982 bladder cancer patients and 5,782 population controls were interviewed. We employed a variety of existing and new techniques to reduce bias and to monitor the quality of data collected. We review here many of the design elements and field methods that can be generally applied in epidemiologic studies, particularly multi-center interview studies, and explain the reasons for our selection of the methods, instruments, and procedures used.

Adult↗
PubMed1984

[H-NMR spectroscopy. Specificity of microbial sialidases against complex substrates].

The specificities of one viral and five bacterial sialidases were investigated by 1H-NMR-spectroscopy with substrates or substrate mixtures containing two sialic acid residues of different linkage types. This technique allows - in contrast to the methods used before - the simultaneous determination of the rates of hydrolysis of both NeuAc linkages in a single experiment. The substrate specificities of the enzymes are discussed on the basis of the relation of the rate constants k/k'. The data obtained are more exact and more informative than those of separate experiments as reported previously. Among the enzymes investigated, i.e. sialidases of fowl plague virus (FPV = VKH), Clostridium perfringens (CP), Vibrio cholerae (VC), Bifidobacterium bifidum var. pennsylvanicum (BBif), Bifidobacterium lactentis (BLac), and Arthrobacter ureafaciens (AU), the activity of the viral sialidase VKH shows the highest, the activities of the Bifidobacterium sialidases the lowest dependence on the nature and on the linkage type of the different substrates. All sialidases preferentially cleave the NeuAc alpha 2-3-Gal linkage with the exception of the enzyme of Arthrobacter ureafaciens (AU) which shows a higher affinity to alpha 2-6 linkages. However, this does not apply to the side-arm-linked NeuAc alpha 2-6 structure in NeuAc alpha 2-3 Gal beta 1-3 (NeuAc alpha 2-6)-GlcNAc beta 1-3Gal beta 1-4Glc (Substrate B). This substrate in generally cleaved very slowly and is hardly affected by the viral enzyme. After the alpha 2-3 linkage, the alpha 2-8 bond in NeuAc alpha 2-8 NeuAc alpha 2-3 Gal beta 1-4Glc(Substrate A) is most susceptible for the sialidases VKH, CP and VC. An elongation of the carbohydrate chain (Substrate D) is accompanied by a reduction of the rate of cleavage for all enzymes. The experiments with alpha 1-acid glycoprotein, fetuin, and with the glycopeptides obtained by proteolytic degradation of the latter, revealed the same specificity towards the alpha 2-3 and the alpha 2-6 linkages as the oligosaccharides. Influenced by the chemical nature and the size of the substrate, NeuAc is released from the native alpha 1-acid glycoprotein more quickly than from the corresponding glycopeptide. All sialidases investigated so far are strictly exo-enzymes as could be demonstrated by the cleavage of NeuAc alpha 2-8 NeuAc alpha 2-3 Gal beta 1-4Glc (Substrate A).

Arthrobacter↗
PubMed1983

Effect of low-molecular-weight lymphokine components on the Fc and C3b receptor-mediated macrophage functions.

Rat lymphokine (LK) components of 500--2500 MW separated on Sephadex G-15 column (FrA) were tested for their effect on Fc and C3b receptor activities of rat resident (rPM) and thioglycollate-provoked (pPM) peritoneal macrophages. Functions of the receptors were studied by measuring the adherence and uptake of 51Cr-labeled sheep red blood cells (SRBC) mediated by isolated rat anti-SRBC IgM or IgG2a antibodies and human C3, respectively. On rPMs mainly Fc mu receptors (Fc mu Rs) were affected by FrA; at low concentration (20 micrograms/ml) adherence was increased and phagocytosis was inhibited. At higher concentrations (40-80 micrograms/ml) a reverse effect was observed: adherence was inhibited and phagocytosis increased. On pPMs IgG2a-mediated functions were mainly affected by FrA with a concentration dependence like that observed with Fc mu Rs on rPM monolayers. A concentration-dependent enhancement of C3b receptor (C3bR)-mediated adherence by FrA was observed on both PM types. On pPms C3bR-mediated phagocytosis was enhanced as well.

Animals↗
PubMed1983

Isolation and physiochemical properties of an adenosine-rich gluten fraction.

Gluten proteins were isolated from the 0.01 mol acetic acid extract of bread. It was observed that precipitation of gluten provoked by 200 mM NaCl could partly be inhibited by adenosine. Based on this finding a method for isolation of the gluten fraction resisting saline precipitation in the presence of adenosine was elaborated. This fraction termed by us gluten-A-S, was found to have a lower glutamine + glutaminic acid and a higher proline and phenylalanine content than gluten. By sodium dodecylsulphate polyacrylamide gel electrophoresis gluten-A-S was shown to contain components of 58 000 and 34 000 dalton molecular weight after mercaptoethanol treatment while without the latter it contained a component of 74 000 dalton. The absorption maximum of the compound is at 260 mm; E280nm/E260nm = 0.5. In accordance with previous findings, gluten-A-S was found to contain 50-100 nmol adenosine per mg protein in a strong binding. It seems that in addition to the small amount of tightly bound adenosine, gluten-A-S contains a larger quantity of adenosine loosely bound to the protein. The physiological effects of dissociable adenosine bound to gluten and its possible role in the pathomechanism of gluten sensitive enteropathy is discussed in detail.

Adenosine↗
PubMed1981

Purification and characterization of the chymotrypsin-like enzyme of the bovine granulocyte.

A chymotrypsin-like enzyme (EC 3.4.21.20) was isolated from bovine granulocytes, and purified 14-fold by affinity chromatography on 4-phenylbutylamine Affi-gel. The molecular weights of the isoenzymes were estimated as 16 000, 19 300 and 24 000 by SDS-polyacrylamide gel electrophoresis. A Michaelis constant of 2 mM and a catalytic constant of 34.6 s-1 were determined with Bz-Tyr-OEt. The esterolytic activity of the enzyme could be inhibited both by PMSF and by TPCK. It was also inhibited by chymostatin (Ki = 0.11 microgram/ml) and by the cytosol inhibitor of the bovine granulocyte (K'i = 1 microM). The chymotrypsin-like enzyme of the bovine granulocyte shares a number of the kinetic properties common to the chymotrypsin-like enzyme of the human granulocyte. The two granulocytes showed nearly identical chymotrypsin-like enzyme activities per cell.

Animals↗
PubMed1981

Effect of lymphokine on the activation and Fc receptor expression of rat macrophages.

Lymphocyte supernatant (LS) containing lymphokine (LK) activated rat peritoneal macrophages (PM) and at the same time enhanced their Fc receptor (FcR) activity. The signs of the early activation could not be observed on alveolar macrophages (AM) but the augmented FcR expression occurred under the effect of lymphokine. The LK-induced macrophage activation and the enhancement of erythrocyte-antibody (EA) rosette formation were found to be independent of each other. In the presence of soybean trypsin inhibitor (STI) the crude lymphokine-induced augmented EA rosette formation was only slightly diminished. However, it did not seem likely that the LK components of molecular weight over 15,000 could enhance the number of rosettes under the effect of protease inhibitor. These data indicate that the macrophage proteases play an important role in the generation of EA rosette formation enhancing breakdown product(s) during the macrophage-lymphokine interaction.

Animals↗