Biomedical subjects

S Wagner

Publications and source records attributed to S Wagner.

At least 271 records · Page 15Linked to original sources

PubMed1994

Oleic acid inhibition of Na+/D-glucose transport in isolated renal brush-border membranes: role of lipid physical parameters and trans Na(+)-inhibition.

UNLABELLED: Inhibition of Na+/D-glucose transport by oleic acid was investigated in renal brush-border membrane vesicles (BBMV). Lipid physical parameters were determined by spectrofluorometry. cis-Unsaturated C16-C22 long-chain fatty acids (LCFA) as oleic acid reduced nonzero limiting anisotropy r infinity with DPH and 12-AS as probes and decreased rotational correlation time phi of 12-AS. At 8 s and 15 s Na+/D-glucose transport was competitively inhibited. A positive correlation existed between decrease in r infinity (acyl chain order) or decrease in rotational correlation time phi (= increase in 'fluidity') and inhibition of Na+/D-glucose transport. Except elaidic acid trans unsaturated and saturated LCFA had no effect on fluorescence anisotropy and Na+/D-glucose transport. Per cent transport inhibition was unaffected by 0 voltage clamping and by FCCP. Ki for trans Na(+)-inhibition of D-glucose transport was 29 mmol/l. Na(+)-transport was stimulated by oleic acid, exceeding the Ki value for trans Na+ inhibition. CONCLUSION: oleic acid inhibits Na+/D-glucose transport by a decrease in lipid acyl chain order and an increase in 'fluidity', by trans Na(+)-inhibition and presumably by a third unknown mechanism.

Animals↗

PubMed1994

[Neurocysticercosis].

A 49-year-old woman from Croatia, resident in Switzerland for 22 years, had a history of headaches and arterial hypertension for 8 years. While in hospital for assessment and treatment she developed focal seizures. She had an eosinophilia (10%) and computed tomography of the skull demonstrated cysts and multiple calcified foci in the left cerebral hemisphere. Antibodies against Taenia solium antigen were found in both serum and cerebrospinal fluid. Anthelminthic treatment with albendazole (15 mg/kg daily for 25 days) and anticonvulsive treatment with phenytoin (serum levels between 10 and 20 mg/l) markedly improved the symptoms and the cysts regressed. Neurocysticercosis, caused by the larvae of the pork tapeworm, is occurring even more frequently because of the migration of people from countries where the disease is endemic.

Albendazole↗

PubMed1994

Generation of glycerophospholipid molecular species in the yeast Saccharomyces cerevisiae. Fatty acid pattern of phospholipid classes and selective acyl turnover at sn-1 and sn-2 positions.

Acyl chains linked to phospholipids of the yeast, Saccharomyces cerevisiae, are mainly C16:1 and C18:1 accompanied by minor amounts of C14:0, C16:0 and C18:0. In view of this rather simple fatty acid composition, the question arose whether in yeast, as in higher eukaryotes, fatty acyl groups were characteristically distributed among the sn-1 and sn-2 positions of distinct phospholipid classes. Analysis of fatty acids linked to the sn-1 and sn-2 positions of the major phospholipids showed that indeed saturated fatty acyl groups predominated in the sn-1 positions. While the percentage of saturated fatty acids was low (10%) in phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) from cells grown on rich medium, it was higher in phosphatidylserine (PtdSer) (25%) and highest in phosphatidylinositol (PtdIns) (41%). Oleate was mainly linked to position sn-2, while palmitoleate predominated in position sn-1. Striking differences in the fatty acid distribution of phospholipids that are metabolically closely related (e.g. PtdSer and PtdEtn, PtdEtn and PtdCho, and PtdIns and PtdSer) suggest that pathways must exist for the generation of distinct phospholipid molecular species within the different phospholipid classes. The highly selective incorporation of exogenous [14C]palmitic acid (90%) and [3H]oleic acid (99%) into the sn-2 position of PtdCho, and the preferential incorporation of these fatty acids into the sn-2 position of PtdEtn (70 and 90%, respectively, for palmitic and oleic acid) are compatible with the postulate that phospholipase A2-mediated deacylation followed by reacylation of the lysophospholipids is involved in the generation of phospholipid species in yeast.

Acylation↗

PubMed1994

Stability of genomic DNA fragment patterns in methicillin resistant Staphylococcus aureus (MRSA) during the course of intra- and interhospital spread.

The analysis of genomic DNA fragment patterns has revealed as a powerful tool for strain discrimination in Staphylococcus aureus; for use as an epidemiological marker, stability during the course of an outbreak is an essential prerequisite. Genomic DNA fragment patterns (SmaI restriction, pulsed-field electrophoresis) of four different epidemic MRSA strains were compared along with intra- and interhospital and country-wide spread over more than 12 months in Germany. Strain I was isolated from infections in 8 hospitals. In one hospital a subclone arised which differed from the original strain by 4 fragments. Strain II was spread among 4 hospitals, isolates from three of these hospitals exhibited a variability of one to three fragments in the 150-200 kb range. Two hospitals in the Hannover-area were affected by strain III; in 17 isolates of this strain a variability up to three fragments was found in the 170-200 kb range. Strain IV was isolated from 19 cases of infections in 3 hospitals in Berlin. The fragment patterns were completely stable. When S. aureus strains are typed by genomic DNA fragment patterns, a variability in a definite range of molecular masses during the course of an epidemic should be taken into consideration.

Cross Infection↗

PubMed1994

Tissue characterization using intelligent adaptive filter in the diagnosis of diffuse and focal liver disease.

In ultrasonic imaging an adaptive two-dimensional filter (ATDF) can suppress randomly generated speckle using the ratio of the local variance to the local mean as the speckle recognition feature (R). The degree of smoothing depends on the difference between the recognition feature in the region to be filtered and the selected reference tissue. We have investigated the clinical application of ATDF for ultrasound B-mode images of liver abnormalities. Using the R values of normal liver as reference values, the ATDF images were displayed. Normal livers (n = 17, R = 2.19 +/- 0.14 M +/- SEM), fatty livers (N = 16, R = 1.89 +/- 0.15) and those with acute hepatitis (N = 10, R = 2.25 +/- 0.18) appeared smooth after application of the adaptive filter, but those diseases with higher R values, such as chronic hepatitis (N = 10, R = 3.04 +/- 0.30), cirrhosis (n = 16, R = 4.44 +/- 0.30), metastases (N = 16, R = 6.43 +/- 0.53) and hepatocellular carcinomas (N = 8, R = 7.92 +/- 0.85), were largely unsmoothed. In conclusion, ATDF allows differentiation of some forms of liver disease and may be helpful in the detection of microfocal echogenic textural lesions.

Adult↗

PubMed1994

DNA-binding domains: targets for viral and cellular regulators.

Specific DNA binding by eukaryotic transcription factors is conferred by several types of sequence motif. These domains have been extensively studied with regard to their precise interaction with DNA and the basis of sequence specificity. Evidence is accumulating that DNA-binding domains serve functions in addition to binding DNA: they are also targets of viral and cellular regulatory proteins.

Animals↗

PubMed1994

Benign lymph node hyperplasia and lymph node metastases in rabbits. Animal models for magnetic resonance lymphography.

OBJECTIVES: Experimental models of reactive lymph-node hyperplasia and lymph-node metastasis were developed for magnetic resonance imaging (MRI). METHODS: Reactive lymph-node hyperplasia was induced in 20 rabbits by injection of an egg-yolk emulsion intramuscularly in the hind limbs and subcutaneously in the flanks. In another 20 rabbits, lymph-node metastasis was induced by implantation of a squamous cell carcinoma (VX2 tumor) in one hind limb. Five rabbits remained untreated. Signal intensity and size of iliac medical and popliteal lymph nodes were investigated with T1-, T2-, and proton-density-weighted spin-echo sequences at 1.5 T. In addition, lymph-node activity and metastatic involvement were assessed histologically. RESULTS: Lymph nodes in untreated animals were small and difficult to visualize by MRI. After egg-yolk-induced reactive lymph-node hyperplasia, the enlarged nodes were well demonstrated by MRI. Implantation of VX2 tumors led to different degrees of lymph-node metastasis (micrometastasis, partial and complete metastatic permeation), depending on growth period and size of the primary tumor. In MR images, lymph nodes of untreated, stimulated, and tumor-bearing rabbits were not differentiable by signal intensity. CONCLUSION: Reactive lymph-node hyperplasia induced by interstitial egg-yolk injection and lymph-node metastasis secondary to implantation of VX2 tumors cannot be differentiated by standard MRI. Therefore, these models may serve for testing the efficacy of lymphographic techniques in MRI.

Animals↗

PubMed1994

Interaction of Helicobacter pylori and its fatty acids with parietal cells and gastric H+/K(+)-ATPase.

Helicobacter pylori and the fatty acids produced by this organism were compared for their acid inhibitory activity in isolated parietal cells and their interaction with gastric H+/K(+)-ATPase. H pylori (intact organisms, sonicates, methanolic extracts, and extracts from culture medium) and the fatty acids cis 9,10-methyleneoctadecanoic acid and tetradecanoic acid inhibited at fairly high concentrations histamine- and dibutyryl cyclic adenosine monophosphate stimulated acid production in isolated parietal cells, dissipated (with a slow onset) the H+/K(+)-ATPase created H+ gradient in gastric membrane vesicles, and inhibited H+/K(+)-ATPase activity in a concentration dependent manner. The inhibitory potency of H pylori and the fatty acids in relation to H+/K(+)-ATPase depended on the amount of membrane protein. Bovine serum albumin prevented enzyme inhibition and proton dissipation from gastric vesicles. The data indicate that H pylori establishes its antisecretory action in parietal cells by blocking H+/K(+)-ATPase activity and also by a detergent action at the apical parietal cell membrane. The fatty acids cis 9,10-methyleneoctadecanoic acid and tetradecanoic acid are probably the acid inhibitory factors secreted by H pylori.

Animals↗

PubMed1994

Interaction between Helicobacter pylori and human gastric epithelial cells in culture: effect of antiulcer drugs.

A human in vitro model to study the interaction between Helicobacter pylori and gastric epithelial cells was developed using primary cultures of gastric mucosal cells (isolated from gastric biopsies or operative specimen and maintained in culture for 2 weeks) as well as the well-differentiated human gastric carcinoma cell line HM02, the undifferentiated gastric tumour cell line HM51, and the laryngeal epithelial cell line HEp-2. Primary cultures and all cell lines were exposed to seven isolates of H. pylori isolated from gastritis and duodenal ulcer patients. Microbial adherence was assessed by microscopical evaluation of Giemsa-stained preparations and by culturing the viable bacteria attached to the epithelial cells. All H. pylori isolates adhered to the gastric cells in primary culture, to HM02 cells, and to HEp-2 cells with the greatest binding affinity found in primary gastric cells. No adherence was detected in HM51 cells. H. pylori adherence was dependent on bacterial load, incubation time, and temperature. There was no difference in microbial binding between H. pylori isolates derived from gastritis and duodenal ulcer patients. The effect of antiulcer drugs on H. pylori adherence was investigated by pre-incubating isolates of H. pylori with omeprazole, cimetidine, and bismuth subcitrate. Omeprazole and cimetidine failed to significantly influence microbial adherence. In contrast, bismuth subcitrate already in concentrations below the MIC range decreased H. pylori adherence in gastric epithelial cells and in HEp-2 cells substantially. Our study shows that primary cultured human gastric mucosal cells and the human gastric carcinoma cell line HM02 provide suitable in vitro models for the study of the interactions between H. pylori and the gastric epithelium. This gastric cell model is characterized by a high affinity for H. pylori binding.

Anti-Ulcer Agents↗

PubMed1994

Cerebrospinal fluid levels of amyloid beta-protein precursor are low in Gerstmann-Sträussler-Scheinker disease, Indiana kindred.

We studied levels of amyloid beta-protein precursor (beta PP) in CSF from four patients affected with Gerstmann-Sträussler-Scheinker disease and one asymptomatic gene-carrier from an Indiana kindred. Levels of beta PP were decreased in all affected patients with the lowest levels occurring in the clinically most severely affected patients. Correlation of neuropathology with CSF data in three patients suggested that low beta PP in CSF may be associated with beta PP accumulation in neurites surrounding cortical and cerebellar amyloid deposits.

Aged↗

PubMed1994

Incidence of local CMV infection and acute intestinal GVHD in marrow transplant recipients with severe diarrhoea.

Intestinal biopsy samples derived from 22 consecutive patients with severe diarrhoea (> 1.5 1/day for 3 or more consecutive days) following allogeneic BMT were analysed for the local presence of cytomegalovirus (CMV) and histological and immunohistological alterations described as typical for acute graft-versus-host disease (GVHD). Seventeen patients showed extensive histopathological lesions typical for acute intestinal GVHD grade > I, 14 marked GVHD-related immunohistological alterations. In intestinal biopsies from 10 of these 22 patients CMV-DNA was detected using PCR- and in situ hybridisation techniques. In 7 of these 10 CMV-DNA positive samples CMV protein expression and in 5 cytomegalic cells were demonstrated. CMV could predominantly be shown in biopsies obtained from the ascending colon and/or the terminal ileum. All 10 patients with local CMV infection showed severe histopathological and immunohistological alterations described as typical for acute intestinal GVHD. Five of seven patients with a CMV-positive intestinal biopsy showed marked improvement of lower gastrointestinal tract disease on antiviral therapy. Five of seven patients lacking local presence of CMV but with severe histopathological lesions responded to therapy with high-dose steroids. Thus, PCR screening for CMV and histopathological analysis may help to treat lower intestinal disease in the marrow transplant recipient early and effectively.

Adolescent↗

PubMed1994

[Effect of rejuvenation on the rheologic properties of stored erythrocytes].

Buffycoat free red cell concentrates in a medium composed of sodium chloride, adenine, glucose and mannitol (SAGM) stored for 42 days at +4 degrees C were rejuvenated by a solution which contained pyruvate, inosine, disodiumphosphate and adenine (PIPA). The rheological behaviour of red cells was measured before and after rejuvenation by viscosimetry of red cell suspensions (hematocrit 45%) at various intervals during the storage period. The deformability of the red cells during storage was determined also before and after rejuvenation by measurement of the viscosity of hard packed cells (hematocrit 98%). The results show improvement of the rheological properties by rejuvenation. Moreover it is shown that incubation of the red cells at 37 degrees C for two hours without rejuvenation solution decreases the viscosity.

Adenine↗

PubMed1994

Clinical application of three-dimensional sonography in hepatobiliary disease.

The diagnostic value of a novel three-dimensional (3D) ultrasound method was analyzed in 93 patients with chronic liver disease, and was compared with conventional 2D sonography. In 26 of 93 patients (28%) 3D sonography was superior to 2D sonography. 3D sonography improved the assessment of the extent and localization of liver tumors (9/20). In 2 of 5 Budd Chiari patients 3D sonography refined the visualization of vascular thrombi. Correct detection of the number of gallstones and their localization within the biliary tree was enhanced by 3D sonography (8/16), especially in cases of cystic duct and prepapillary stones. The assessment of the extent of biliary tract alterations in primary sclerosing cholangitis was superior in 3D sonography (4/7). In contrast, 3D imaging did not add important information in diffuse liver disease. Our results indicate that 3D imaging is superior to routine sonography in the anatomical assignment of complex vascular and biliary duct alterations, while there is no obvious benefit in diffuse liver disease so far.

Adult↗

PubMed1994

[Callus distraction with the AO tubular fixator--principles, techniques and clinical examples].

Callus distraction in segmental transport for closure of traumatic or operative bone defects can be performed with the AO tubular fixator in various ways. Depending on the soft tissue situation and personal preference segmental shifting may either be achieved by tension wires running through the soft tissues (Augsburg model) or by percutaneous Schanz' screws (Basel model). Transportation along an intramedullary nail has certain advantages but also specific draw-backs. To be able to apply the optimal technique to a given situation it is necessary to be familiar with each of these methods. A hybrid system under development at this moment will facilitate anchorage in short epiphyseal segments. We are also going to have a clamp which can turn in itself for correction of axial malalignment.

Adult↗

PubMed1994

The Budd-Chiari syndrome: clinical presentation and diagnostic findings in 45 patients treated by surgery.

We report on the clinical presentation and diagnostic findings in 45 patients with Budd-Chiari syndrome. The diagnosis was confirmed by histology at the time of liver transplantation (n = 37) or shunt surgery (n = 8). An underlying disorder could be established only in half of the patients, oral contraceptives as predisposing factor were known in 18 cases. Clinically, abdominal pain and distension as well as hepatomegaly and ascites were most frequent findings, whereas changes in laboratory data were more or less unspecific. By use of repeated ultrasound, a definite diagnosis of a Budd-Chiari syndrome could be confirmed in all cases by obligatory demonstration of obstruction or thrombosis of at least one major liver vein. Hepatic venography revealed only one false-negative result. Celio-mesenteric arteriography plus portography, cavography and preoperative liver biopsy did not present additional diagnostic information. These techniques may contribute to treatment planning of portosystemic shunt surgery or hepatic transplantation. In conclusion, the presence of hepatosplenomegaly, ascites, abdominal pain and distension, especially in combination with a known hypercoagulable state, should alert to the possibility of a Budd-Chiari syndrome. Ultrasound is the diagnostic tool of choice. Hepatic venography should only be performed if even repeated ultrasound is not conclusive.

Adolescent↗

PubMed1994

Helicobacter pylori infection and serum pepsinogen A, pepsinogen C, and gastrin in gastritis and peptic ulcer: significance of inflammation and effect of bacterial eradication.

OBJECTIVES: To study the relationship between Helicobacter pylori infection, gastric inflammatory scores, and fasting gastrin and pepsinogen A and C concentrations, and to evaluate the effect of treatment on these parameters. METHODS: Gastrin and pepsinogen A and C concentrations were measured in 36 patients with gastritis, 10 gastric ulcer patients, 12 duodenal ulcer patients, and in 15 subjects with normal gastric mucosa, by standard radioimmunoassay techniques. Fifteen patients with H. pylori infection underwent triple therapy (bismuth subsalicylate, amoxicillin, metronidazole) and were reassessed 1 month later. RESULTS: Fasting gastrin and pepsinogen A and C concentrations were significantly higher in H. pylori-positive gastritis and peptic ulcer patients than in subjects with normal mucosa and in patients with H. pylori-negative gastritis. There was a significant correlation between inflammatory scores and serum gastrin (r = 0.45, p < 0.0001), and pepsinogen A (r = 0.33, p < 0.006) and pepsinogen C (r = 0.55, p < 0.0001) concentrations. Neither sex nor age affected basal gastrin and pepsinogen concentrations. Eradication of H. pylori infection was successful in 12 patients and resulted in a significant fall in serum gastrin and in pepsinogen A and C concentrations, and in a concomitant improvement of the inflammatory scores. Serum peptide levels and gastritis scores were unchanged in those patients in whom H. pylori infection persisted. CONCLUSIONS: These findings suggest that hypergastrinemia and hyperpepsinogenemia are secondary to H. pylori infection and are related to mucosal inflammation.

Amoxicillin↗

PubMed1994

Elevated plasma concentration of neuropeptide Y in adolescents with primary hypertension.

Neuropeptide Y (NPY) has been recently characterised as a circulating vasoconstrictor peptide which is co-stored with noradrenaline (NA) in sympathetic neurons. We measured NPY by radioimmunoassay and NA by HPLC in plasma of ten healthy volunteers (23-27 years of age) during bicycle ergometry and found a rapid increase of both NPY and NA during exercise. NPY rose from 1.3 +/- 0.5 to 9.6 +/- 7.8 pmol/l and NA from 1.3 +/- 0.3 to 10.8 +/- 5.6 mnol/l (mean +/- SD). Following maximal exercise NA disappeared more rapidly from plasma than NPY. Compared with these healthy volunteers, plasma NPY was found to be elevated in 23 children and adolescents aged 9-18 years with borderline primary hypertension (NPY 3.1 +/- 1.7 pmol/l, P < 0.01). Basal NPY was also elevated when compared with 21 age-matched pediatric controls (P < 0.05). The bicycle ergometry protocol performed in 23 patients separated ten adolescents with normal basal and exercise blood pressure from 13 with high BP also during ergometry. In the latter group, NPY rose to 11.9 +/- 7.3 pmol/l and NA to 12.3 +/- 8.6 nmol/l during exercise. Treatment of the hypertensive patients with the beta-adrenergic blocker atenolol (50 mg per day) lowered basal and exercise BP. Heart rate fell during atenolol treatment from 92 +/- 19 to 72 +/- 15 beats/min. Treatment did not alter plasma concentrations under basal conditions and during exercise (NPY from 2.8 +/- 2.1 to 11.7 +/- 5.3 pmol/l and NA from 2.0 +/- 0.8 to 15.6 +/- 14.1 nmol/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

HTLV-I Tax protein stimulation of DNA binding of bZIP proteins by enhancing dimerization.

The Tax protein of human T cell leukemia virus type-1 (HTLV-I) transcriptionally activates the HTLV-I promoter. This activation requires binding sites for activating transcription factor (ATF) proteins, a family of cellular proteins that contain basic region-leucine zipper (bZIP) DNA binding domains. Data are presented showing that Tax increases the in vitro DNA binding activity of multiple ATF proteins. Tax also stimulated DNA binding by other bZIP proteins, but did not affect DNA binding proteins that lack a bZIP domain. The increase in DNA binding occurred because Tax promotes dimerization of the bZIP domain in the absence of DNA, and the elevated concentration of the bZIP homodimer then facilitates the DNA binding reaction. These results help explain how Tax activates viral transcription and transforms cells.

Activating Transcription Factor 1↗