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C Wagner

Publications and source records attributed to C Wagner.

At least 181 records · Page 10Linked to original sources
PubMed1995

Folate deficiency inhibits pancreatic amylase secretion in rats.

Previous studies have suggested that the metabolism of methyl groups is an important factor in the function of the exocrine pancreas. Ethionine, an inhibitor of cellular methylation reactions, produces hemorrhagic pancreatitis when administered to mice fed a choline-deficient diet. Glycine N-methyltransferase, an enzyme which regulates the ratio of S-adenosylmethionine to S-adenosylhomocysteine, is particularly abundant in the exocrine pancreas. Since de novo synthesis of methyl groups requires the participation of folate coenzymes, we investigated the effect of folate deficiency on pancreatic exocrine function. Rats were fed an amino acid-defined folate-deficient diet or the same diet supplemented with folate ad libitum. A third group received the folate supplemented diet pair-fed to the deficient group. After 3 and 5 wk, pancreatic amylase secretion was measured in perfused duodenal segments of anesthetized animals before and after cholecystokinin injection. Pancreatic secretion was significantly reduced in the deficient group compared with the pair-fed control group after 5 wk. These results indicate that severe folate deficiency impairs pancreatic exocrine function.

Aging↗
PubMed1995

Ras gene mutations: a rare event in nonmetastatic primary malignant melanoma.

Ras gene mutations have been implicated in the pathogenesis of a variety of human tumors. Mutated ras genes have been isolated from human melanoma cell lines, but subsequent studies indicated that ras gene mutations may be a rare event in melanocytic lesions. Recently, a study reported a high frequency of ras mutations correlated with increasing invasion level. To address this inconsistency in the published data, we analyzed 50 primary melanomas to correlate invasion level, tumor thickness, histologic typing, and body localization with point mutations around codons 12/13/61 of the three ras genes. After micro-dissection of paraffin-embedded tumor tissue, ras gene mutations were analyzed by direct sequencing of tumor DNA amplified by polymerase chain reaction. Only two melanomas exhibited ras gene mutations, one sample containing a transition from A to G at position 2 of N-ras codon 61 and the other exhibiting a transversion from C to A at position 1 and a transition from A to G at position 2 of N-ras codon 61. Both tumors were classified as Clark level IV, with a tumor thickness of 2.5 and 1.2 mm, respectively. Both were typed as superficial spreading melanoma and localized to intermittently sun-exposed body sites. The low frequency of ras mutations in malignant melanoma and the lack of ras mutations in melanoma samples from constantly sun-exposed body sites argue against the hypothesis of ras mutations as a marker of progression in malignant melanoma and the suggestion that ras mutations occur predominantly in melanomas from constantly sun-exposed body sites.

Base Sequence↗
PubMed1995

Can penicillins and other beta-lactam antibiotics be used to treat tuberculosis?

An increase in the number of tuberculosis cases caused by multiple-drug-resistant strains of Mycobacterium tuberculosis has stimulated search for new antituberculous agents. Beta-lactam antibiotics, traditionally regarded as ineffective against tuberculosis, merit consideration. Four major penicillin-binding proteins (PBPs) with approximate molecular sizes of 94, 82, 52, and 37 kDa were detected by fluorography of [3H]penicillin-radiolabeled membrane proteins prepared from M. tuberculosis H37Ra. The presence of membrane-associated beta-lactamase precluded the use of membranes for assaying the binding affinities of beta-lactam antibiotics. Therefore, ampicillin affinity chromatography was used to purify these four PBPs from crude membranes in order to assay the binding affinities of beta-lactam antibiotics. Ampicillin, amoxicillin, and imipenem, beta-lactam antibiotics previously reported to be active in vitro against M. tuberculosis, bound to M. tuberculosis PBPs at therapeutically achievable concentrations. Binding of the 94-, 82-, and 52-kDa PBPs, but not the 37-kDa PBP, was associated with antibacterial activity, suggesting that these PBPs are the critical targets. Studies of mycobacterial cell wall permeability, which was assayed with a panel of reference cephalosporins and penicillins with different charge positivities, indicated that the rate of penetration of beta-lactam antibiotics to the target PBPs could not account for resistance. Resistance could be reversed with the beta-lactamase inhibitors clavulanate or sulbactam or could be circumvented by the use of a beta-lactamase-stable drug, imipenem, indicating that mycobacterial beta-lactamase, probably in conjunction with slow penetration, is a major determinant of M. tuberculosis resistance to beta-lactam antibiotics. These findings confirm in vitro data that M. tuberculosis is susceptible to some beta-lactam antibiotics. Further evaluation of these drugs for the treatment of tuberculosis in animal models and in clinical trials is warranted.

Animals↗
PubMed1995

Quantitative culture of Mycobacterium tuberculosis from clinical sputum specimens and dilution endpoint of its detection by the Amplicor PCR assay.

The minimum number of Mycobacterium tuberculosis CFU detectable in clinical sputum specimens by the Amplicor PCR test was estimated by performing the test on duplicate samples of quantitatively cultured serial dilutions of sputum. Positive PCR test results were obtained for all samples that contained 42 CFU of M. tuberculosis. The detection limits of the PCR assay for decontaminated (N-acetyl-L-cysteine [NALC]-NaOH) and nondecontaminated (NALC only) specimens were equivalent, even though the number of CFU cultured from decontaminated samples was only 11 to 20% of the number cultured from nondecontaminated samples. Thus, the 42 CFU that could be detected in nondecontaminated specimens by the Amplicor PCR test correspond to the approximately 8 CFU (0.20 x 42) that could be recovered in culture after decontamination with NALC-NaOH.

Bacteriological Techniques↗
PubMed1995

Comparison of the single breath with the intrabreath method for the measurement of the carbon monoxide transfer factor in subjects with and without airways obstruction.

BACKGROUND: Measurement of the carbon monoxide transfer factor (TLCO) has traditionally been performed using the single breath method but recently the intrabreath method has been developed. The aim of this study was to compare the two methods in the clinical evaluation of patients with obstructive and non-obstructive pulmonary disorders. METHODS: Measurements of TLCO with the intrabreath method were carried out on a study sample composed of 50 patients with non-obstructive disorders and 50 with airways obstruction (FEV1/FVC < 70%) either before or after a single breath measurement of the TLCO had been performed. The method involves the continuous analysis of a single slow expirate using a computerised rapid multigas infrared analyser. TLCO, alveolar volume (VA), TLCO/VA, and inspired vital capacity (IVC) values were obtained for both groups by both methods. RESULTS: When measured with the intrabreath method the group with airways obstruction showed lower TLCO and TLCO/VA values than the non-obstructive group. VA was higher in both patient groups when measured with the intrabreath technique. The same test also showed higher TLCO values with the intrabreath method in the group with non-obstructive disorders and lower TLCO/VA values with the intrabreath method in those with airways obstruction. The corresponding parameters obtained by the two methods correlated closely, with no correlation between the magnitude of the differences with the magnitude of the readings. An index of gas mixing indicated a better distribution of the inspired air for the intrabreath method than for the single breath method. The VA values obtained with the intrabreath method showed a closer agreement to the actual total lung capacities measured by body plethysmography. CONCLUSION: The intrabreath method of determining TLCO is comparable to the traditional single breath method. Measurement of alveolar volume by the intrabreath method approximates more closely to total lung capacity, even in subjects with airways obstruction.

Adult↗
PubMed1995

Nasal function and bronchial hyperresponsiveness to methacholine in children.

The objective of the present study was to investigate nasal function by active anterior rhinomanometry with respect to spirometric data and bronchial hyperresponsiveness to methacholine in 9-year-old children. The study population consisted of 300 children (ages 8 to 11 years; mean, 9.3 years; 161 male, 139 female), who underwent basal rhinomanometry followed by a decongestion test and a lung function test consisting of spirometry and a methacholine provocation test. The flow values of the basal rhinomanometry showed a significant correlation with height and bronchial hyperresponsiveness. The consecutive decongestion test showed a marked increase in flow rates at each level, which was found to be significantly higher in children with bronchial hyperresponsiveness (p < 0.01). The spirometric data showed no influence on rhinomanometric values. These results suggest that nasal dysfunction and reactivity in terms of the decongestion test may be associated with bronchial hyperresponsiveness in children.

Airway Resistance↗
PubMed1995

Modulation of urokinase and urokinase receptor gene expression in human renal cell carcinoma.

In vivo and in vitro experimental models have suggested a major role for the urokinase-type plasminogen activator (uPA) in tumor cell invasion and metastasis. The uPA proteolytic activity of tumor cells has been shown to be largely determined by the extent of the expression and saturation of the uPA receptor. We have analyzed the expression and cellular localization of both uPA and uPA receptor at the protein and mRNA levels in 33 paired samples of renal cell carcinoma (RCC) and non-tumorous kidney tissue. In comparison with adjacent normal non-tumorous kidney tissues RCC tumor cells modestly overexpressed uPA-receptor mRNA and showed significantly decreased uPA mRNA expression. However, the immunoreactive uPA content of tumor cells was comparable to that of the surrounding normal non-tumorous kidney tissue. Assuming constancy of the uPA-receptor affinity for uPA this indicates that a proportion of the RCC-associated uPA may be derived from an exogenous source and subsequently concentrated at the tumor cell surface via uPA receptor expression. The modest increase in uPA receptor expression may lead to a normalization of uPA antigen content in RCC; however, it is not sufficient to substantially increase tumor tissue-uPA content over the level of normal non-tumorous kidney tissue.

Blotting, Northern↗
PubMed1995

[Sensitization to inhaled allergens in the Vienna population].

The present study investigated the sensitization to inhalatory allergens in a randomized cross-section of the population of Vienna (altogether 3000 men and women). A representative sample of 600 persons was invited to an examination consisting of a skin prick test and determination of serum total IgE and allergen-specific IgE. In addition, the same tests were performed in persons with asthma or allergic rhinitis on the basis of a history of these conditions in the replies to a screening questionnaire. Our results showed comparatively high sensitization rates to grass pollen (28%), house dust mite (25%) and cat dander (20%) in the randomized group A. In the symptom-free "healthy" subgroup of the randomized population sample (Group B) there were remarkably high sensitization rates to house dust mite (21%), grass pollen (17%) and cat dander (12%). For the group with allergic rhinitis (Group D) sensitization to grass pollen exceeded 60%, followed by cat dander (44%), birch pollen (36%) and house dust mite (35%). In the asthmatic persons (Group C) the leading allergens were cat dander (40%) and the house dust mite (37%), followed by grass pollen (33%) and birch pollen (20%). Regarding the overall sensitization to inhalatory allergens 61% of the asthmatic group showed a positive prick test. Increased serum levels of total IgE or specific IgE were found in 76% of cases, which underlines the allergic origin of this disease. In the randomized group 51% were sensitized to inhalatory allergens, whilst 39% were subclinically sensitized without ever having had any allergic complaints.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Expression cloning of the cDNA encoding a melanoma-associated Ag recognized by mAb HMB-45. Identification as melanocyte-specific Pmel 17 cDNA.

BACKGROUND: mAb HMB-45 recognizes a melanocyte lineage-associated Ag present in "activated melanocytes" and malignant melanoma cells. Despite its important practical significance in diagnostic pathology and its potential role as an "activation marker" of melanocytic cells, the HMB-45-reactive Ag remained undefined. Molecular characterization of the HMB-45-reactive Ag may help in analyzing underlying mechanisms of melanocyte activation and melanoma tumor progression. EXPERIMENTAL DESIGN: A cDNA library constructed from the HMB-45-immunoreactive human melanoma cell line SK-MEL-28 was screened for expression of the cDNA encoding the HMB-45-reactive protein. Screening was performed by expression in COS-7 cells and subsequent immunocytochemical screening. Correlation between HMB-45 immunoreactivity and mRNA expression of the cloned cDNA was analyzed by antisense mRNA expression in HMB-45-immunoreactive SK-Mel-28 cells, by Northern blot hybridization, and by comparative immunohistochemistry and in situ hybridization. RESULTS: A cDNA clone encoding the HMB-45-reactive Ag was isolated and shown to be homologous to the Pmel 17 cDNA. Expression of either HMB-45 or Pmel 17 cDNA in COS-7 cells induced cytoplasmic HMB-45 immunoreactivity as described for melanoma cells. Conversely, constitutional HMB-45 immunoreaction in SK-MEL-28 cells could be markedly reduced by expression of antisense Pmel 17 RNA. In several tissues, Pmel 17 mRNA content conformed to the known expression pattern of HMB-45-reactive Ag. Comparative in situ hybridization and immunohistochemistry demonstrated a consistent co-localization of Pmel 17 transcripts and HMB-45-reactive Ag at the cellular level, with strong expression in "activated" melanocytes and melanoma cells and significantly less expression in normal adult melanocytes. CONCLUSIONS: We conclude that Pmel 17 cDNA encodes the HMB-45-reactive Ag. Pmel 17 has been postulated to be involved in melanin synthesis and expression of melanoma-peptide epitopes recognized by CTLs. Differential expression of Pmel 17/HMB-45 may have considerable effects in the stepwise process of melanoma progression by aberrant pigment formation and expression of CTL-reactive epitopes.

Antibodies, Monoclonal↗
PubMed1994

Peptide inhibitors of src SH3-SH2-phosphoprotein interactions.

Activated pp60c-src has been implicated in a number of human malignancies including colon carcinoma and breast adenocarcinoma. Association of the src SH2 domain with tyrosine-phosphorylated proteins plays a role in src-mediated signal transduction. Inhibitors of src SH2 domain-phosphoprotein interactions are, thus, of great interest in defining the role(s) of src in signal transduction pathways. To facilitate such studies, an enzyme-linked immunosorbent assay (ELISA) was developed to detect inhibitors of src SH2-phosphoprotein interactions. This assay measures inhibition of binding of a fusion construct (glutathione S-transferase src SH3-SH2) with autophosphorylated epidermal growth factor receptor tyrosine kinase domain. Activities of phosphopeptide segments derived from potential src SH2 cognate phosphoprotein partners were determined, with the focal adhesion kinase-derived segment VSETDDY*AEIIDE yielding the highest inhibitory activity. Structure activity studies starting from acetyl (Ac)-Y*EEIE have identified Ac-Y*Y*Y*IE as the most active compound screened in the ELISA. This compound is at least 20-fold more active than the parent peptide Ac-Y*EEIE. A high resolution (2 A) crystal structure of human src SH2 complexed with Ac-Y*EEIE was obtained and provided a useful framework for understanding the structure-activity relationships. Additionally, Ac-Y*EEIE was able to block interactions between src and its cellular phosphoprotein partners in vanadate-treated cell lysates from MDA-MB-468 breast carcinoma cells. However, it is unable to abrogate proliferation of MDA-MB-468 cells in culture, presumably because of poor cell penetration and/or lability of the phosphate group on tyrosine.

Amino Acid Sequence↗
PubMed1994

A high throughput fluorogenic substrate for stromelysin (MMP-3).

Stromelysin, a member of the matrix metalloproteinase family of enzymes, has been implicated in the pathogenesis of tumor metastasis and inflammatory diseases such as rheumatoid arthritis. To screen prospective inhibitors of this protease, we developed a fluorogenic substrate with excitation and emission spectra compatible with commercially available 96-well plate readers. The substrate is based on the addition of 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino] hexanoic acid (NBD) (EX467/EM534) and 7-dimethylaminocoumarin-4-acetate (DMC) (EX368/EM459) to the previously reported peptide substrate for stromelysin, Arg-Pro-Lys-Pro-Leu-Ala-Nva-Trp-NH2. The new substrate, NBD-Arg-Pro-Lys-Pro-Leu-Ala-Nva-Trp-Lys-(DMC)-NH2 is 95% quenched and the fluorescent product, Nva-Trp-Lys(DMC)-NH2 is easily detected (EX350/EM465). In competition assays the new fluorogenic substrate has a relative kcat/Km that is one half that of the parent peptide. The fluorophores NBD and DMC were chosen based on the high fluorescence yield of DMC and the overlap of the emission spectrum of DMC and excitation spectrum of NBD which results in an efficient energy transfer system in the intact substrate. These characteristics make this an excellent substrate for routine determination of in vitro activities of stromelysin inhibitors.

Amino Acid Sequence↗
PubMed1994

Rat liver cytosolic 4 S polycyclic aromatic hydrocarbon-binding protein is glycine N-methyltransferase.

In the rat, cytochrome P-450IA1 gene expression, which is most closely associated with aryl hydrocarbon hydroxylase activity, is thought to be regulated by several trans-acting factors, including the 4 S polycyclic aromatic hydrocarbon (PAH)-binding protein. This protein has been purified to homogeneity from rat liver using ion exchange, gel permeation, hydrophobic interaction, and affinity chromatographies. Partial sequencing of the 33-kDa band indicated its identity as glycine N-methyltransferase (GNMT). Polyclonal antibodies to GNMT immunoprecipitated PAH-binding activity from rat liver cytosol. Methyltransferase and PAH-binding activities copurified during the course of protein purification. GNMT protein and PAH binding activity were colocalized in various cytosolic fractions. These data all indicate that the 4 S PAH-binding protein and GNMT are one and the same protein or very similar proteins. Western blot analyses yielded a positive signal under denaturing (33 kDa) and nondenaturing (150 kDa, tetramer) conditions; the PAH-binding protein also was an oligomer. GNMT was detected by immunohistochemistry in nuclei from H4IIE rat hepatoma cells and rat liver. The localization of GNMT in liver nuclei is in accordance with a role in modulating cytochrome P-450IA1 gene expression.

Amino Acid Sequence↗
PubMed1994

Tissue distribution of glycine N-methyltransferase, a major folate-binding protein of liver.

Glycine N-methyltransferase (GNMT; S-adenosyl-L-methionine:glycine N-methyltransferase, EC 2.1.1.20) is a major protein in rat liver that binds 5-methyltetrahydrofolate polyglutamate in vivo. This enzyme is believed to function in the regulation of the availability of S-adenosylmethionine, the primary donor of methyl groups in the body. The distribution of GNMT in a variety of rat tissues was examined immunohistochemically. In liver, GNMT was most abundant in the periportal region, whereas in kidney it was seen primarily in the proximal convoluted tubules. In pancreas, GNMT was abundant, principally in the exocrine tissue. GNMT was present in the striated duct cells of the submaxillary gland. In the jejunum, GNMT was found in the epithelial cells of the villi. Close examination of the liver indicated GNMT in the nucleus; this site was confirmed by purification of the nuclei and measurement of enzyme activity. The location of GNMT in the liver and kidney suggests that this enzyme plays a role in gluconeogenesis, while its presence in the exocrine cells suggests it may also be a factor in secretion.

Animals↗
PubMed1994

Factors contributing to the occurrence and predictability of bronchial hyperresponsiveness to methacholine in children.

Using a stepwise logistic regression analysis, we investigated clinical data, allergologic findings, spirometric data, and the cellular and humoral immune system in order to gain new insights into the role these parameters play in bronchial hyperresponsiveness to methacholine in children and to create a model for the prediction thereof. Bronchial hyperresponsiveness, which was found in 124 of 462 children (26.8%), was observed to have been influenced by an increased level of eosinophils, the positivity of the skin prick test for any of the allergens tested, a decreased baseline forced expiratory volume in 1 second (FEV1) (percent predicted), a decreased maximum expiratory flow at 50% expiration as a percent of forced vital capacity, and a decreased level of kappa-chain-assembled immunoglobulins. Logit analysis disclosed that the influence of all other parameters on the occurrence of bronchial hyperresponsiveness was of no further statistical significance. The degree of bronchial hyperresponsiveness (provocative dose causing a 20% fall in FEV1) showed a statistically significant correlation with the eosinophil count (Spearman's r = -0.198) and FEV1 (percent predicted) (Spearman's r= 0.203). Our findings suggest that allergic sensitization and eosinophilic reaction in children are major factors in contributing to the occurrence of bronchial hyperresponsiveness to methacholine.

Allergens↗
PubMed1994

Prediction of sensitization to flour allergens.

The purpose of the present study was to investigate the factors that may contribute to the sensitization to flour in baker's apprentices, and to predict this type of sensitization with a stepwise logistic regression model. Of the total of 258 baker's apprentices, 54 (20.9%) exhibited specific IgE development against flour allergens (wheat, rye, and/or barley). Allergologic variables, such as the total IgE level and IgE specific to grass pollen, tree pollen, weed pollen, molds, and animal dander, were found to correlate strongly with the sensitization to flour. However, the correlation between the presence of other manifest allergies and the sensitization to flour was weak. The presence of shadowing of the paranasal sinuses on the radiograph (mucosal thickening, opacity, air/fluid levels, and/or polypous shadowing) correlated with flour sensitization as well as with the leukocyte and lymphocyte counts in peripheral blood. Of the lung function data, only total lung capacity (in percentage of the predicted values) weakly correlated with the sensitization to flour. We were able to predict flour sensitization with a sensitivity of 63%, a specificity of 90%, and an efficiency of 84% by using the parameters that allow for the presence or absence of IgE specific to grass pollen and tree pollen, the presence or absence of radiographic shadowing, and total lung capacity in percentage of the predicted values.

Allergens↗
PubMed1994

Effects of the sauna on diffusing capacity, pulmonary function and cardiac output in healthy subjects.

The present study examined possible short-term effects of the heat stress during sauna bathing on gas exchange, especially in correlation with changes in cardiac output. The results obtained are as follows: (1) The heat stress of sauna bathing caused a slight but not significant increase in diffusion capacity (p = 0.239) and no change in other pulmonary function parameters. (2) Cardiac output and cardiac index increased slightly but not significantly (p = 0.2455 and p = 0.2719). We conclude that heat stress in sauna neither influences gas exchange nor does it cause a significant increase in cardiac output.

Adolescent↗
PubMed1994

Chest X-ray in collagen vascular diseases. A comparison of chest X-ray with bronchoalveolar lavage and transbronchial forceps biopsy.

The diagnostic value of chest X-ray following the ILO standards was compared with bronchoalveolar lavage (BAL) and the histology of transbronchial forceps biopsy in 83 patients with collagen vascular diseases. BAL in the middle lobe was considered abnormal in case of increased cell count per milliliter and/or lymphocytosis and/or neutrophil granulocytosis and this was found in 32 out of 42 cases (76.2%) with, and in 33 of out 41 cases (80.5%) without abnormal radiological finding. Pathological changes in the histology were found in 14 out of 20 cases (70.0%) with and in 40 out of 63 cases (63.5%) without abnormal chest X-ray in the upper lobe from which the transbronchial forceps biopsy specimens were obtained. In histological specimens obtained from transbronchial forceps biopsy, only fibrosis correlated with abnormal radiological findings in this region. Other inflammatory processes defied prediction by chest X-ray. This suggests that, regardless of chest X-ray findings, BAL should be performed together with transbronchial forceps biopsy for the histological examination of patients with collagen vascular diseases in which interstitial lung involvement is suspected.

Adolescent↗