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Biomedical subjects

C Wagner

Publications and source records attributed to C Wagner.

At least 19 recordsLinked to original sources
PubMed1992

Purification and properties of pancreatic glycine N-methyltransferase.

Glycine N-methyltransferase (GNMT) regulates the ratio of S-adenosylmethionine to S-adenosylhomocysteine. It is very abundant in liver cytosol and earlier studies have shown it to be present in high concentrations in the pancreas. We have previously reported that liver GNMT is allosterically inhibited by 5-methyltetrahydrofolate pentaglutamate (5-CH3-H4PteGlu5), and proposed that this represents a metabolic control mechanism which links the de novo synthesis of methyl groups to the methylating ability of the liver. We now report that pancreatic GNMT also contains bound folate in vivo. Purified pancreatic GNMT is inhibited by reduced folate polyglutamates in vitro. The KI for the synthetic (R,S)5-CH3-H4PteGlu5 is 2.4 x 10(-7) M. The natural (S) form of 5-CH3-H4PteGlu5 is tightly bound and has a Kd of 1.3 x 10(-7) M. One mole is bound per enzyme tetramer. These studies suggest that GNMT is important in the regulation of methyl group metabolism in the pancreas as well as in the liver.

Animals↗
PubMed1992

Multicentric evaluation of a new assay for prothrombin fragment F1+2 determination.

A multicenter study of a recently developed ELISA for the determination of prothrombin fragment F1+2 was performed in order to evaluate analytical and clinical aspects. Mean intra-assay and inter-assay reproducibility were found to be 11.0 and 12.6%, respectively. The measuring range covered by the calibration curve reaches from 0.04 to 10.0 nM/l F1+2. Testing 133 healthy subjects a reference range of 0.37 to 1.11 nM/l F1+2 (2.5-97.5 percentile) with a median of 0.66 nM/l F1+2 was calculated. Minor difficulties with blood sampling (venous occlusion for 2 min) did not affect F1+2 plasma concentrations. Significantly increased F1+2 levels were measured in patients with leukemia (p < 0.0001), severe liver disease (p < 0.005) and after myocardial infarction (p < 0.01). Elevated F1+2 concentration before the beginning of heparin therapy (1.25 nM/l) decreased to 0.77 nM/l (p < 0.0001) after 1 day of therapy. For patients in the stable phase of oral anticoagulant therapy decreasing F1+2 concentrations were measured with increasing INR. F1+2 levels were already significantly reduced in patients with INR < 2.0 (0.56 nM/l; p = 0.0005). Thus F1+2 determination may be helpful in identifying activation processes as well as in monitoring anticoagulant therapy.

Administration, Oral↗
PubMed1992

Methyl group metabolism in the pancreas of folate-deficient rats.

Several studies have suggested that the metabolism of one-carbon compounds may have a special role in the function of the exocrine pancreas. An amino acid-defined diet was used to produce folate deficiency in a group of male rats. These rats were compared with a group of rats pair-fed the same diet supplemented with adequate folate and with a third group fed the folate-supplemented diet with ad libitum access. Pancreatic folate concentrations were already severely depleted after 4 wk of feeding the deficient diet (0.95 +/- 0.10, 5.81 +/- 0.29 and 4.58 +/- 0.30 nmol/g for the deficient, pair-fed control and ad libitum-fed control groups, respectively). The level of folate present in the pancreas of nondeficient animals was second only to that reported for liver. Urinary amylase excretion by animals in the deficient group was higher than that by the other groups (245.5 +/- 21.9, compared with 181.9 +/- 14.5 and 195.3 +/- 10.9 units/mg creatinine for the deficient, pair-fed control and ad libitum-fed control groups, respectively) after 4 wk. The ratio of S-adenosylmethionine to S-adenosylhomocysteine was 18.6 +/- 1.6 and 14.5 +/- 1.0 after 4 wk for the ad libitum-fed control and pair-fed control groups, respectively, but was significantly lower at 6.3 +/- 1.1 for the deficient group. These results indicate a profound effect of folate deficiency upon methyl group metabolism of the pancreas and suggest that this may result in decreased pancreatic function.

Animals↗
PubMed1992

On the move.

Explore the source record for details and available documents.

Indiana↗
PubMed1992

Horse chestnut (Aesculus hippocastanum) pollen: a frequent cause of allergic sensitization in urban children.

We investigated the incidence of allergic sensitization and the risk factors underlying sensitization in 214 urban children exposed to horse chestnut pollen. By means of the Phadezym RAST, we found IgE specific to horse chestnut pollen in 12.6% of the urban children, whereas it occurred in only 1.9% of control subjects recruited from a rural area. Reports of allergic symptoms in spring during the horse chestnut pollen load coincided with the presence of specific IgE in 5.1% of the urban group as against 1.4% of the recruited from the rural area. Environmental factors other than those related to urban living and higher horse chestnut pollen counts had no significant impact on allergic sensitization. Increased total IgE levels (greater than 100 kU/l), however, and the sensitization to pollen of other species significantly raised the odds for sensitization to chestnut pollen. They were highest in highly atopic children with sensitization to pollen, especially to that of plane trees (OR = 73.9). These results suggest the relevance of horse chestnut pollen because of the high allergic sensitization rate among urban children, and they should also be borne in mind when it comes to the planting of trees in urban areas.

Allergens↗
PubMed1992

Immune damage to the mesangium: antibody- and complement-mediated stimulation and destruction of mesangial cells.

The deposition of immune complexes in the tissue results in complement activation leading to the formation of the lytic C5b-9 complex. Tissue cells are relatively resistant to complement attack due to cellular mechanisms such as removing C5b-9 from the surface and the expression of membrane proteins, which regulate complement activation and attack on the cell surface. Hence, cell killing is not an important consequence of complement activation on nucleated cells. On the other hand, the sublethal C5b-9-membrane interaction leads to various cellular responses, among them the synthesis of eicosanoids, cytokines, matrix-degrading proteases, and extracellular matrix, resulting in the modification of cell proliferation, leukocyte function, matrix degradation, and the formation of scar tissue. Thus, the complement-dependent immune damage is caused by secondary mediators, either derived from leukocytes or mesangial cells, rather than by a direct C5b-9-mediated killing.

Animals↗
PubMed1992

[Cryptosporidium parvum and Giardia lamblia--incidence in surface and drinking water--significance and detection].

Cryptosporidium parvum and Giardia lamblia are protozoan parasites which can cause gastroenteritis in man and animal. Surface water and drinking-water play an important role in transmission of the disease. The parasites can be detected by extensive and time-consuming procedures only. In this paper we describe a new way to isolate C. parvum and G. lamblia from water by a modification of essential steps of the original method of Rose. The new method applies the separation by flow centrifugation, the purification by different filters and the parasite isolation by percoll density gradient centrifugation. The modified method allows reproducible and by 20% increased recovery rates of cysts. Due to this fast and easy technique this procedure can be integrated in routine examinations.

Animals↗
PubMed1991

Isolation and characterization of cDNA clones for rat liver 10-formyltetrahydrofolate dehydrogenase.

We have isolated and characterized cDNA clones encoding rat liver cytosol 10-formyltetrahydrofolate dehydrogenase (EC 1.5.1.6). An open reading frame of 2706 base pairs encodes for 902 amino acids of Mr 99,015. The deduced amino acid sequence contains exact matches to the NH2-terminal sequence (28 residues) and the sequences of five peptides derived from cyanogen bromide cleavage of the purified protein. The amino acid sequence of 10-formyltetrahydrofolate dehydrogenase has three putative domains. The NH2-terminal sequence (residues 1-203) is 24-30% identical to phosphoribosylglycinamide formyltransferase (EC 2.1.2.2) from Bacillus subtilis (30%), Escherichia coli (24%), Drosophila melanogaster (24%), and human hepatoma HepG2 (27%). Residues 204-416 show no extensive homology to any known protein sequence. Sequence 417-900 is 46% (mean) identical to the sequences of a series of aldehyde dehydrogenase (NADP+) (EC 1.2.1.3). Intact 10-formyltetrahydrofolate dehydrogenase exhibits NADP-dependent aldehyde dehydrogenase activity. The sequence identity to phosphoribosylglycinamide formyltransferase is discussed, and a binding region for 10-formyltetrahydrofolate is proposed.

Amino Acid Sequence↗
PubMed1991

[Biosynthesis of anthracycline: a new interpretation of the results for daunomycin biosynthesis].

On the basis of literature data and our own experiments the "late" biosynthetic pathway to daunomycin has been interpreted from a new point of view considering both the in vivo biosynthesis and formation of shunt products. In contrast to existing hypotheses proposed by other authors we discuss a modified sequence leading to C-11 oxidation and, as a consequence, understand epsilon-rhodomycinone as a shunt product instead of a biosynthetic intermediate. In addition, a new hypothesis about the "early" steps of the ring formation from polyketides by a sequence of enzyme reactions has been proposed.

Antibiotics, Antineoplastic↗
PubMed1991

Renal cortical nephrocalcinosis: a manifestation of extrapulmonary Pneumocystis carinii infection in the acquired immunodeficiency syndrome.

A 38-year-old man with acquired immunodeficiency syndrome (AIDS) demonstrated atypical nephrocalcinosis on abdominal x-ray. Computed tomography (CT) scanning showed the calcifications to be predominantly in a cortical distribution. The patient had evidence of disseminated Pneumocystis carinii infection, and histologically the renal calcifications occurred in areas of renal Pneumocystis infection. Intrarenal infection with Pneumocystis carinii can be added to the causes of nephrocalcinosis. However, the radiologic picture is so unique that it should suggest the diagnosis in the appropriate patient.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Personal spore sampling and indirect immunofluorescent test for exploration of hypersensitivity pneumonitis due to mould spores.

Sensitization to mould spores was investigated in six patients with hypersensitivity pneumonitis, eight patients with idiopathic lung fibrosis, and six healthy controls by immunodiffusion and immunofluorescent testing of personal spore samples. The new technique of personal spore sampling with the Burkard personal volumetric air sampler and indirect immunofluorescent test for detection of spore-specific IgG and IgM confirmed that five patients with hypersensitivity pneumonitis and four with lung fibrosis were actually exposed and sensitized to moulds. Personal spore sampling and subsequent immunofluorescent tests represent sensitive tools for detection of individual mould sensitization and air quality control.

Adult↗
PubMed1991

Pollen sensitization and allergy in children depend on the pollen load.

We investigated the influence of grass and birch pollen load on specific IgE response, skin prick test reactivity, and manifest allergic disorders of the eyes and respiratory tract. The study population was two groups of 200 children each, matched in sex and age, who were domiciled in areas with high and low pollen load, respectively. In the children from the area with high pollen load, the grass pollen load was 1.7 times higher than in the other and only specific IgE to grass pollen was found to be present more frequently (23.5% as against 12.5%; P less than 0.01). In the same area, the birch pollen load was 2.8 times higher, which caused specific IgE in 10.5% as against 3.5% of the other group (P less than 0.01) as well as positive skin prick test in 9.0% as against 3.5% (P less than 0.05). Reports of subjective complaints were rare among the group with high pollen load but the total number did not amount to a statistically significant increase. There was no difference between the two groups concerning sensitization and allergy to house dust mite. This suggests that the influence of the pollen load is strongest on the development of specific IgE, and less on skin test reactivity and manifest allergies.

Air Pollutants↗