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Biomedical subjects

S Neumann

Publications and source records attributed to S Neumann.

At least 109 records · Page 6Linked to original sources
PubMed1986

X-ray crystal structure of the complex of human leukocyte elastase (PMN elastase) and the third domain of the turkey ovomucoid inhibitor.

Orthorhombic crystals diffracting beyond 1.7 A resolution, have been grown from the stoichiometric complex formed between human leukocyte elastase (HLE) and the third domain of turkey ovomucoid inhibitor (OMTKY3). The crystal and molecular structure has been determined with the multiple isomorphous replacement technique. The complex has been modeled using the known structure of OMTKY3 and partial sequence information for HLE, and has been refined. The current crystallographic R-value is 0.21 for reflections from 25 to 1.8 A resolution. HLE shows the characteristic polypeptide fold of trypsin-like serine proteinases and consists of 218 amino acid residues. However, several loop segments, mainly arranged around the substrate binding site, have unique conformations. The largest deviations from the other vertebrate proteinases of known spatial structure are around Cys168. The specificity pocket is constricted by Val190, Val216 and Asp226 to preferentially accommodate medium sized hydrophobic amino acids at P1. Seven residues of the OMTKY3-binding segment are in specific contact with HLE. This interaction and geometry around the reactive site are similar as observed in other complexes. It is the first serine proteinase glycoprotein analysed, having two sugar chains attached to Asn159 and to residue 109.

Animals↗
PubMed1986

Granulocyte elastase as a new biochemical marker in the diagnosis of chronic joint diseases.

Human granulocyte elastase (EC 3.4.21.37) is released from granulocytes in large amounts in chronic inflammatory joint diseases and is therefore of special pathogenic and diagnostic importance. In order to examine the diagnostic significance of this enzyme as a clinico-chemical parameter, we determined the concentration of granulocyte elastase in complex with alpha 1-proteinase inhibitor by an enzyme immunoassay in synovial fluids and plasma of patients with chronic joint diseases. In inflammatory synovial fluids the concentration of complexed elastase correlates well with the granulocyte number and may increase to an extremely high level. In 90% of patients with manifest rheumatoid arthritis increased elastase levels are also observed in the plasma, probably due to the large gradient between the synovial fluid and plasma concentration, whereas in osteoarthrosis normal plasma concentrations were observed. Thus, these results indicate that normal plasma concentrations in patients with chronic joint diseases exclude the diagnosis of rheumatoid arthritis with high probability. The simultaneous determination of complexed elastase in plasma and synovial fluid improves the nosological differentiation of chronic joint diseases. Elastase activity on a specific chromogenic substrate, which was found in many inflammatory synovial fluids, is mainly attributed to elastase alpha 2-macroglobulin complexes. In some purulent synovial fluids, however, we were able to detect free elastase, which has been shown to play an important role in the destruction of articular cartilage.

Adolescent↗
PubMed1986

Purification, partial characterization and substrate specificity of a squalene cyclase from Bacillus acidocaldarius.

From the thermophilic Bacillus acidocaldarius, a membrane bound cyclase catalysing the formation of 22(29)-hopene (diploptene) and 22-hopanol (diplopterol) from squalene was enriched 670-fold to a purity of 95% as judged by gel chromatography. The specific activity of the purified enzyme in the presence of Triton X-100 is 0.22 mumol product formation per min and mg protein at 54 degrees C. The molecular mass is 150 kDa and that of the subunits 80 kDa as determined by FPLC gel chromatography and sodium dodecyl sulfate gel electrophoresis, respectively. Not only squalene but also E,E-homofarnesol, homogeraniol and homofarnesyl (1,5,9-trimethyl-4,8-decadienyl) ether are substrates. The ether bond of the latter substrate is split by the enzyme. The products of the aforementioned three additional substrates are ambroxan (dodecahydro-3a,6,6,9a-tetramethylnaphtho[2,1-b]-furan), octahydro-4,4,7a-trimethylbenzofuran and ambroxan together with 1,5,9-trimethyl-4,8-decadienol. The cyclization rates of these substrates compared to squalene are 3%, 0.05% and 0.3%, respectively. The half-life of the enzyme activity is 80 h at 45 degrees C and 18 h at 54 degrees C.

Bacillus↗
PubMed1986

Different complement and granulocyte activation in patients dialyzed with PMMA dialyzers.

Plasma C3a and C5a levels as well as plasma levels of granulocyte lactoferrin, granulocyte myeloperoxidase and granulocyte elastase in complex with alpha 1-proteinase inhibitor (E-alpha 1PI) were investigated in 10 patients (52.7 +/- 5.9 years) undergoing maintenance hemodialysis (39.4 +/- 12.4 months) with hollow fiber dialyzers made from polymethylmethacrylate. Plasma levels of lactoferrin increased from 166.5 +/- 28.5 to 712.5 +/- 165.9 ng/ml, myeloperoxidase from 59.0 +/- 15.3 to 210.5 +/- 33.9 ng/ml and E-alpha 1PI from 114.2 +/- 18.1 to 681.8 +/- 102.6 ng/ml during dialysis. In contrast, plasma C3a levels rose from 179.8 +/- 33.6 to maximal 276.2 +/- 45.4 ng/ml and C5a from 55.7 +/- 8.1 to maximal 101.1 +/- 14.8 ng/ml. Our data indicate that degranulation of granulocytes occurs during dialysis despite only little complement activation and mild initial granulocytopenia.

Biocompatible Materials↗
PubMed1986

Granulocyte proteinases as mediators of unspecific proteolysis in inflammation: a review.

In severe inflammatory response, various blood and tissue cells, including polymorphonuclear granulocytes, release lysosomal proteinases, extracellularly and into the circulation. Such enzymes, as well as normally intracellular oxidizing agents produced during phagocytosis, enhance the inflammatory response by degrading connective tissue structures, membrane constituents and soluble proteins by proteolysis or oxidation. We first used polymorphonuclear elastase (E) as a marker of such release reactions. The liberated proteinase competes with susceptible substrates, including alpha 1-proteinase inhibitor (alpha 1PI) and alpha 2-macroglobulin, and is eliminated finally as inactive enzyme-inhibitor complexes by the reticulo-endothelial system. Using an enzyme-linked immunosorbent assay, we determined the plasma levels of E-alpha 1PI following major abdominal surgery, multiple trauma and pancreatogenic shock. Whereas the operative trauma was followed by up to 3-fold increase of the E-alpha 1-PI, postoperative septicemia was associated with a 10 to 20 fold increase. The increase of E-alpha 1-PI and a concomitant decrease of plasma factors, such as antithrombin III, clotting factor XIII and alpha 2-macroglobulin, were correlated. Multiple trauma causes a substantial increase of E-alpha 1-PI up to 14 hours after accident. The released elastase seems to correlate with severity of injury, but assessing the relationship to consumption of plasma factors is complicated by concomitant transfusions. In acute pancreatitis, peaks, of E-alpha 1-PI coincide with a massive consumption of antithrombin III and alpha 2-macroglobulin during shock.

Blood Proteins↗
PubMed1986

Improvement of dialyzer compatibility by reduction of membrane surface area.

The present study was devised to investigate, whether reduction of membrane surface area would contribute to enhanced dialyzer membrane compatibility. Therefore, 10 hemodialysis patients were dialyzed with three different cuprophan dialyzers, displaying membrane surface areas of 0.9 m2, 1.2 m2, and 1.8 m2. As an index of biocompatibility release of granulocyte elastase and secretion of granulocyte lactoferrin were determined by enzyme-linked immunoassays. With the three cuprophan membranes, marked leukopenia occurred 15 min after the start of hemodialysis, without significant distinction between the different membranes. On the other hand, the release of leukocyte elastase was strictly dependent on the membrane surface area. Thus, at the end of dialysis, plasma levels of elastase were as follows: 0.9 m2: 255 +/- 51; 1.2 m2: 356 +/- 65; 1.8 m2: 471 +/- 56 ng/ml. The magnitude of secretion of leukocytic lactoferrin was also dependent on membrane surface area. Therefore, the increment during dialysis was 300% with the 1.2 m2 membrane compared to 650% using a 1.8 m2 dialyzer. Based upon these data, we concluded that, using measurements of granulocyte degranulation as an index of biocompatibility, reduction of membrane area resulted in a marked improvement of membrane compatibility.

Adult↗
PubMed1985

Chiral products from non-pyridine nucleotide-dependent reductases and methods for NAD(P)H regeneration.

Enoate reductase (EC 1.3.1.31) from a Clostridium tyrobutyricum strain catalyses the stereospecific reduction of many different alpha, beta-unsaturated carboxylates, aldehydes and even some ketones. The enzyme accepts electrons from NADH and, 1.5 times faster, from reduced methyl viologen (1,1'-dimethyl-4,4'-bipyridinium). Another new type of non-pyridine nucleotide-dependent reductase has an extremely broad substrate specificity for 2-oxo-carboxylates and 2-oxo-dicarboxylates. In crude extracts from Proteus mirabilis and Proteus vulgaris, specific activities of 2-12 mumol product formed per mg protein per min can be found when reduced methyl or benzyl viologen is used as electron donor. The products are (2R)-hydroxy acids. Enoate reductase and 2-oxo-carboxylate reductase are suitable for electro-enzymic reductions in which catalytic amounts of viologens are continuously reduced in an electrochemical cell. This procedure has three advantages: (1) regeneration of NAD(P)H by a second enzyme and substrate is not required, (2) the unstable pyridine nucleotides are not required in the reaction mixture, and (3) the rate of the reaction can be observed continuously by measuring an electric current. Several yeasts, as well as aerobic and anaerobic bacteria, catalyse the reduction of NAD(P)+ by reduced methyl viologen. Such cells can be used for electro-microbial reductions when only pyridine nucleotide-dependent reductases are present. Information about the enzymes which catalyse the reduction of NAD(P)+ at the expense of reduced methyl viologen is given.

Alcohol Oxidoreductases↗
PubMed1985

Circulating human leucocyte elastase in patients with inflammatory bowel disease.

The plasma concentration of human leucocyte elastase (HLE), measured by enzyme immunoassay as the complex with alpha 1-proteinase inhibitor, was determined in 94 patients with active and inactive inflammatory bowel disease. In Crohn's disease and in ulcerative colitis human leucocyte elastase levels were raised significantly above normal when the disease was active, and fell on remission. The mean human leucocyte elastase level in 31 cases of active Crohn's disease was significantly greater than the mean human leucocyte elastase level in 23 patients with active ulcerative colitis (p = 0.013). The values of human leucocyte elastase correlated significantly with Crohn's disease activity index scores (p = 0.05) and with the circulating concentration of C-reactive protein (p less than 0.05 and p less than 0.01 for ulcerative colitis and Crohn's disease respectively), but not with the erythrocyte sedimentation rate. These results indicate that the concentration of human leucocyte elastase in the plasma of patients with inflammatory bowel disease reflects the activity of their intestinal disease and suggest that serial measurements of human leucocyte elastase may be useful in the assessment and clinical management of these conditions.

Adolescent↗
PubMed1984

Granulocyte lysosomal factors and plasma elastase in uremia: a potential factor of catabolism.

In uremic intoxication proteolytic activity in plasma and striated muscle is enhanced. To get further insights into the underlying mechanisms the lysosomal factors of polymorphonuclear (PMN) leukocytes and the plasma elastase-alpha 1-proteinase inhibitor complex were investigated in patients with acute and chronic renal failure. Lysosomal activity was evaluated in peripheral blood smears by the lysis of erythrocytes and plasma (halo formation) around each neutrophil induced by 0.25 M NaC1 borate buffer. In about half of the patients with chronic renal insufficiency on dietary treatment lysosomal activity of PMN leukocytes was reduced. The plasma concentration of elastase-alpha 1-proteinase inhibitor complex was normal in most subjects, but increased in three patients with the highest serum creatinine levels (greater than 13 mg/d1). In the patients with acute renal failure (ARF) of various origin (postoperatively, septicemia, pancreatitis, or dye-induced) halo formation was either reduced or absent. The plasma elastase-alpha 1-proteinase inhibitor complex was increased in 5/6 of the patients by a factor of two to four. Also in the patients on regular hemodialysis treatment halo formation of PMN leukocytes was substantially reduced, whereas the plasma levels of elastase-alpha 1-proteinase inhibitor complex was slightly increased. The finding of reduced lysosomal activity of PMN neutrophils in uremia may be partly due to an enhanced release of neutral proteinases into the circulation as indicated by the elevated plasma levels of elastase-alpha 1-proteinase inhibitor complex in some patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1984

Enzyme-linked immunoassay for human granulocyte elastase in complex with alpha 1-proteinase inhibitor.

Granulocyte elastase in complex with its main inhibitor in plasma, i.e. alpha 1-proteinase inhibitor, was quantitatively determined by incubating the sample with solid-phase fixed antibodies against elastase first and reacting then with alkaline phosphatase-labelled antibodies against alpha 1-proteinase inhibitor. In normal plasma a level of 97.5 +/- 25.8 micrograms elastase/1 (mean +/- s.d., n = 43) was found, whereas moderately to markedly increased plasma concentrations were demonstrated in a variety of patients with inflammatory diseases like septicemia or rheumatoid arthritis.

Aged↗
PubMed1984

Release of granulocyte neutral proteinases in patients with acute and chronic renal failure.

In uremic intoxication proteolytic activity in plasma and striated muscle is enhanced. To get further insight into the underlying mechanisms the neutral proteinases of polymorphonuclear (PMN) leukocytes were investigated in patients with acute and chronic renal failure. The following studies were performed: 1. Neutral proteolytic activity of PMN neutrophils in blood smears (according to Klessen, 1978). 2. Serum levels of elastase alpha 1 proteinase inhibitor complex (Neumann et al., 1981). In about half of the patients with chronic renal insufficiency on dietary treatment the proteolytic activity of PMN leukocytes (halo formation are due to digestion of erythrocytes and plasma) was reduced. The serum concentration of elastase alpha 1 proteinase inhibitor complex was normal in most subjects, but increased in 3 patients with the highest serum creatinine levels (greater than 13 mg/dl). In the patients with acute renal failure (ARF) of various origin (postoperatively, septicemia, pancreatitis or dye induced) halo formation was either reduced or absent. Serum elastase alpha 1 proteinase inhibitor was increased in 5/6 patients by a factor of two to four. Also in the 15 patients on regular hemodialysis treatment halo formation was substantially reduced, while the serum levels of elastase alpha 1 proteinase inhibitor complex was slightly increased. The finding of reduced proteolytic activity of PMN neutrophils in uremia is probably due to an enhanced release of proteinases into the circulation as indicated by the elevated serum levels of elastase alpha 1 proteinase inhibitor complex in some patients. The release of proteinases might be in part due to the effect of "uremic toxins". In the RDT patients the contact of the blood with the dialyzer (cuprophane) membrane might be an additional factor. In the patients with ARF the underlying disease (infection, shock, trauma) contributes to the release of proteinases. These disturbances may be harmful for the patient, if the blood concentration or function of the most important proteinase inhibitors (alpha 1 proteinase inhibitor, alpha 2 macroglobulin) is reduced.

Acute Disease↗
PubMed1984

"PMN-elastase assay": enzyme immunoassay for human polymorphonuclear elastase complexed with alpha 1-proteinase inhibitor.

A solid phase, enzyme-linked immunoassay is described for the quantitative determination of the complex of human granulocyte elastase (EC 3.4.21.37) with alpha 1-proteinase inhibitor. The assay employs antibody-coated test tubes and it is suitable for routine use in clinical chemistry laboratories. Data for sample stability and test characteristics are given. A reference range of 20-180 micrograms/l elastase in plasma was determined. The diagnostic significance of granulocyte elastase levels in plasma in inflammatory diseases is discussed.

Blood Proteins↗
PubMed1983

Retinal dysplasia of English springer spaniel dogs: light microscopy of the postnatal lesions.

The histologic features of retinal dysplasia were studied in 26 English springer spaniel dogs of one day to four years of age. Dysplastic lesions in neonatal pups occurred predominantly in the peripapillary tapetal area of sensory retina. They consisted of complex linear folds and rosettes which were composed of hyperplastic neuroblasts. Dysplasia usually was not associated with incomplete differentiation of the outer neuroblastic layer. The outer limiting membrane was absent locally and numerous patent subretinal capillaries existed in the region of folds. The dysplastic features may be related to aberrant development of Muller cells and of retinal capillaries. In adolescent dogs, dysplastic lesions were less complex and usually were not accompanied by aberrant capillaries. Focal or complete retinal separation was present in some adolescent dogs. In adult dogs, features of retinal atrophy were found within dysplastic areas. No significant histologic lesions were found in the extraocular tissues of 12 affected dogs which were surveyed extensively.

Age Factors↗
PubMed1983

Proteolytic enzymes and catabolism: enhanced release of granulocyte proteinases in uremic intoxication and during hemodialysis.

Proteinases are classified into four groups according to their catalytic mechanisms: the serine, cysteine (thiol), aspartic (carboxyl), and metallo-proteinases. Neutrophil granulocytes contain a variety of neutral proteinases and two acid proteinases. Lysosomal proteinases are released from cells during phagocytosis, cell death, or exposure to antigen-antibody complexes, complement factors, and toxins. Under pathological conditions, massive proteinase release may cause tissue injury and degradation of plasma proteins. Plasma proteolytic activity is controlled by inhibitors of blood systems (antithrombin III, C1 inhibitor, and plasmin inhibitor) and by inhibitors against proteinases of various body cells (alpha 1-proteinase inhibitor, alpha 1-antichymotrypsin, beta 1-collagenase inhibitor, and inter-alpha-trypsin inhibitor). Intracellular proteinases are controlled by different cytosolic inhibitors. In hypercatabolic states (septicemia, trauma, burns), the concentrations of many plasma proteins, including proteinase inhibitors, are decreased. Kallikrein-kinin, complement, and fibrinolytic systems may be activated, probably due to enhanced proteinase activity. In acute renal failure, there is a release of granulocyte neutral proteinases. The plasma concentration of the elastase-alpha 1-proteinase inhibitor complex is simultaneously increased. Granulocytes of chronically uremic patients treated with diet or regular dialysis have a slightly to markedly reduced proteinase content as compared with normal controls. There is a dramatic rise of the plasma elastase alpha 1-proteinase inhibitor complex during hemodialysis treatment.

Acute Kidney Injury↗
PubMed1982

Plasticity of cortico-thalamic projections and functional recovery in the unilateral detelencephalized infant rat.

Previous results have shown that the unilateral removal of the telencephalon in adult rats leads to the appearance of crossed connections from the remaining telencephalon to the thalamus one week after the ablation. This study extends this finding to infant rats. The telencephalon structures were unilaterally removed in 7-day-old animals. As in adult rats the ablation induced behavioral asymmetries, including active turning behavior which ceased within the first days after the lesion. Either immediately after the ablation or one week thereafter the animals were injected with horseradish peroxidase (HRP) into the posterior part of the thalamus ipsilateral to the lesion. HRP-labeled cells appeared in the remaining contralateral cortex in animals that were injected one week after the lesion. Rapid functional recovery from the lesion-induced behavioral asymmetries, as indicated, for example, by the cessation of spontaneous turning behavior, may be related to the observed appearance of crossed projections between structures that are normally connected only ipsilaterally.

Animals↗