Search PubMed⌕ Search

Biomedical subjects

S Wagner

Publications and source records attributed to S Wagner.

At least 163 records · Page 9Linked to original sources

[Xanthoma disseminatum with marked mucocutaneous involvement].

HISTORY AND CLINICAL FINDINGS: When aged 23 years, a now 36-year-old man was first diagnosed as having xanthomas on the upper arms and shoulders. Xanthomas then progressed, affecting both the skin and the laryngo-pharyngeal mucosa. They were so marked that several laser-surgical interventions for their removal in the phayngo-laryngeal tract were necessary to ensure unimpaired breathing. There were also extensive confluent symmetrical cutaneous xanthomas over the upper and lower arms, the face, neck and trunk. Xanthomas and scars in the pharynx and larynx necessitated marked nasal breathing. INVESTIGATIONS: There was no laboratory evidence of abnormal lipid metabolism. The concentrations of cholesterol, triglycerides, lipoprotein (a), apolipoprotein A-1, apolipoprotein B, apolipoprotein E phenotype and steroles were all normal. The biochemical composition of LDL, VLDL and HDL particle was also unremarkable. Histological examination of resected xanthomas revealed dense infiltrations of the interstitial spaces by foam-cell histiocytes with multiple lipid vacuoles, typical of xanthoma disseminatum. TREATMENT AND COURSE: Neither probucol nor cholesterol synthesis enzyme inhibitors nor glucocorticoid medication influenced the xanthomas. The only effective treatment was removal of the most unsightly or obstructing lesions. But the sars left removal in the mucocutaneous regions caused obstruction in the laryngopharyngeal tract. CONCLUSION: The cause of xanthoma disseminatum remains unknown. Skeletal muscle can also be extensively infiltrated. This case shows similarities to Erdheim-Chester disease, another are xanthomatous condition.

Adult↗

cDNA cloning of the 43-kDa latex allergen Hev b 7 with sequence similarity to patatins and its expression in the yeast Pichia pastoris.

IgE-mediated hypersensitivity to latex proteins present in health care products, particularly in latex gloves, has become an important public health problem in recent years. We purified natural Hev b 7, a 43-kDa patatin-like allergen from the latex of Hevea brasiliensis and determined several internal peptide sequences. A heterologous hybridization probe of a patatin gene of potato, to which these peptides could be aligned best, was used to screen a latex cDNA library. The cDNA encoded an acidic protein of 388 amino acids with a molecular mass of 42.9 kDa. The deduced amino acid sequence had 39-42% identity to patatins from Solanum tuberosum. The purified recombinant Hev b 7 expressed in the yeast Pichia pastoris displayed, similarly to patatins from S. tuberosum, esterase activity. Both natural and recombinant Hev b 7 were recognized by IgE from sera of latex-sensitized allergic individuals. In contrast to patatins from S. tuberosum and Nicotiana tabacum, natural Hev b 7 lacked an N-terminal leader peptide for targeting to the endoplasmatic reticulum and was not glycosylated. These results establish the 43-kDa patatin-like protein as a latex allergen and raise the possibility of different cellular localization and function compared to S. tuberosum patatins.

Allergens↗

Mechanism of gamma sigma T-cell-mediated inhibition of stem cell differentiation in vitro: possible relevance for myelosuppression in HIV-infected individuals.

We investigated whether gamma delta T cells contribute to the suppression of myelopoiesis in HIV infection. Freshly isolated gamma delta T cells from HIV seropositive patients suppressed CFU-GM growth in vitro. Preactivation of gamma delta T cells with IL-2 and/or IL-15 further reduced the number of CFU-GM. Natural killer cells and to a lower extent CD4+ and CD8+ cells also inhibited CFU-GM growth. In contrast to gamma delta T cells, this effect was not dependent on IL-15 or IL-2 preactivation. Moreover, no enhanced inhibitory effect of CD56+ and CD4+ cells was observed in HIV+ subjects compared to HIV- donors. The myelosuppressive effect of supernatants of gamma delta T cells could be inhibited by antibodies against IFN-gamma or TNF-alpha. Accordingly, we found increased numbers of TNF-alpha or IFN-gamma-secreting CD8+ gamma delta T cells in HIV+ patients. We conclude that the increased fraction of activated gamma delta T cells producing myelosuppressive cytokines might contribute to the dyshematopoiesis frequently observed in HIV-infected individuals.

Cell Differentiation↗

The dominant chloride channel mutant G200R causing fluctuating myotonia: clinical findings, electrophysiology, and channel pathology.

Clinical, electrophysiological, and molecular findings are reported for a family with dominant myotonia congenita in which all affected members have experienced long-term fluctuations of the symptom of myotonia. In some patients myotonia is combined with myalgia. The myotonia-causing mutation in this family is in the gene encoding the muscular chloride channel, hCIC-1, predicting the amino acid exchange G200R. We have constructed recombinant DNA vectors for expression of the mutant protein in tsA201 cells and investigation of the properties of the mutant channel. The most prominent alteration was a +100-mV shift of the midpoint of the activation curve. Therefore, within the physiological range the open probability of the mutant channel is markedly smaller than in wild-type. This shift is likely to be responsible for the myotonia in the patients. The fluctuating symptoms of this chloride channelopathy are discussed with respect to short-term fluctuations of myotonia in the sodium channelopathy of potassium-aggravated myotonia.

Adolescent↗

Targeting of ultrasmall superparamagnetic iron oxide (USPIO) particles to tumor cells in vivo by using transferrin receptor pathways.

Human transferrin was covalently coupled to ultrasmall superparamagnetic iron oxide (USPIO) particles, and the transferrin-USPIO obtained was investigated in vivo in experimental SMT/2A tumor-bearing rats (rat mammary carcinoma). Physicochemical characterization showed an overall size of 36 nm (DLS) with a core size of 5 nm (TEM). Relaxivities were R1 = 23.6 and R2 = 52.1 liter/mmol.s (0.47 T). Bound transferrin was 280 micrograms/mg of iron. Pharmacokinetic investigations revealed a half-life of 17 min in normal rats. The MR evaluation of tumor signal intensity over time showed a 40% (range 25-55%) signal reduction 150 min after injection with the reduction persisting for at least 8 h. Control experiments using the parent USPIO compound or USPIO labeled with a nonspecific human serum albumin (HSA-USPIO) showed a change of only 10% (range 5-15%) in tumor signal intensity over time. The results demonstrate that a combination of the USPIO relaxivity properties with the specificity of transferrin-mediated endocytosis allows in vivo detection of tumors by MR imaging.

Animals↗

Stimulation of pepsinogen release from chief cells by Helicobacter pylori: evidence for a role of calcium and calmodulin.

To define the mechanisms by which Helicobacter pylori stimulates pepsinogen secretion, the in vitro release of pepsinogen was studied using a preparation of pig chief cell monolayers. Helicobacter pylori induced a time- and concentration-dependent release of pepsinogen into the medium, with about a three-fold increase in pepsinogen secretion over controls found after 45 min of incubation. 3x10(7) H. pylori produced 50% of the maximal response found at a H. pylori count of 2x10(8). The action of H. pylori did not depend on the presence of the vacuolating toxin (vacA) and the cytotoxin-associated protein (cagA). Dibutyryl-cAMP and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate also markedly stimulated pepsinogen secretion and enhanced the stimulatory effect of H. pylori. Helicobacter pylori-stimulated pepsinogen release was inhibited by lanthanum and the calmodulin antagonist W-7, but not by the L-type Ca2+ channel blocker nifedipine, TMB-8, an agent that blocks the release of Ca2+ from intracellular stores, the protein kinase C inhibitor staurosporine and the protein kinase A inhibitor H-8. It is suggested that H. pylori directly stimulates pepsinogen release from gastric chief cells and that this effect is mediated via the calcium/calmodulin messenger branch.

Animals↗

Myelin splitting, Schwann cell injury and demyelination in feline diabetic neuropathy.

Nerve biopsy samples from two cats with spontaneously occurring diabetes were examined. The predominant nerve fiber abnormalities observed were restricted to the myelin sheath and Schwann cell. Reactive, degenerative and proliferative Schwann cell changes were evident but the most striking abnormality encountered was splitting and ballooning of the myelin sheath. These observations highlight the significance of Schwann cell injury in the pathogenesis of diabetic neuropathy.

Animals↗

Morphological and molecular characterization of human gastric mucous cells in long-term primary culture.

A primary cell culture of human gastric mucous cells was developed using enzymatic treatment of surgically obtained gastric mucosal specimens. Preferential attachment of gastric mucous cells during a preincubation step resulted in the enrichment of mucous cells [over 90% stained with periodic acid-Schiff (PAS) and mucin-type lectins] in the primary cell culture. Gastric mucous cells could be maintained in culture for 10 days. DNA synthesis peaked during the first 2 days in culture (8+/-1% bromodeoxyuridine-positive cells). During the entire culture period gastric mucous cells released high-molecular-weight glycoproteins into the medium, as determined by gel chromatography on a Sepharose CL-4B column and by metabolic labelling with [14C]-N-acetylglucosamine. Gastric mucin was verified by gas chromatographic analysis of the carbohydrate composition and fractionation of the void-volume fraction by density gradient centrifugation. Determination of the terminal glycosylation of the secreted glycoproteins by a lectin-ELISA revealed that there was a high quantity of alpha-l-fucose. Prostaglandin E2 significantly stimulated glycoprotein secretion during the entire cultivation period by 29-60%. Analysis of mucin-encoding MUC mRNA expression by reverse transcriptase polymerase chain reaction revealed that gastric mucous cells predominantly express MUC1 and MUC5AC, and to a lesser extent MUC6, which reflects the expression pattern obtained following analysis of biopsied samples of gastric mucosa. This primary cell culture model enables the regulation of mucin secretion and mucin gene expression in man to be investigated.

Cells, Cultured↗

Electrosurgical safety.

Technological advances in safety and the performance of electrosurgical units (ESUs) have made the ESU the most common piece of electrical equipment in the OR. The constant presence of the ESU in the OR increases the potential for patient injury that is associated with the use of any piece of electrical equipment. To prevent injuries related to the use of an ESU, the perioperative nurse must understand the types of current used, types of ESUs available, and potential complications and have a working knowledge of safe practices for using this equipment in the perioperative setting.

Electricity↗

Effects of PGE2 and of different synthetic PGE derivatives on the glycosylation of pig gastric mucins.

The glycosylation of pig gastric mucins, discharged in response to prostaglandin (PG) E2 and to three synthetic PGE-derivatives (misoprostol, nocloprost, rioprostil) was compared. After a 20 h culture period in the absence or presence of 1 micromol/l of one of the PGs, mucins were isolated by gel chromatography and their glycosylation characterized by their linkage to a panel of lectins. For all tested PGs, a significantly increased lectin linkage to mucin glycoproteins of high molecular weight was detected; no significant effects were observed for low molecular weight glycoproteins. Within the stimulatory pattern, major effects were found for the linkage of peanut agglutinin and soybean agglutinin, suggesting predominant effects on the expression of galactose and N-acetyl-galactosamine. Only minor effects were found for sialic acid, mannose, N-acetyl-glucosamine and fucose expression, as evidenced by the linkage of Sambucus nigra agglutinin, Concanavalin A, Datura stramonium agglutinin and Ulex europaeus I agglutinin. All PGs exerted a similar stimulatory pattern. However, at the indicated concentration, misoprostol (281 +/- 36% of control) rendered a significantly higher overall effect than PGE2 (208 +/- 31%), whereas the increases induced by nocloprost (237 +/- 35%) and rioprostil (202 +/- 35%) were not significantly different from the PGE2 effects. These results, suggesting similar stimulatory effects of PGE2 and of the tested synthetic PGs on glycosylation of mucin oligosaccharides, discharged from mucous cells during an in vitro culture, may, at least in part, explain clinical findings that during an impairment of the endogenous PG synthesis, the tested synthetic PGs are effective exogenous substitutes for endogenous E-type prostaglandins and act as anti-ulcer drugs.

Acetylgalactosamine↗

Helicobacter pylori fatty acid cis 9,10-methyleneoctadecanoic acid increases [Ca2+]i, activates protein kinase C and stimulates acid secretion in parietal cells.

The effect of the Helicobacter pylori (H. pylori) fatty acid cis 9,10-methyleneoctadecanoic acid (MOA) on gastric acid secretion was studied in isolated guinea-pig parietal cells. MOA (1 and 3 micromol/l) stimulated basal and enhanced histamine- and dibutyryl cyclic AMP-stimulated acid secretion in parietal cells. MOA increased intracellular free [Ca2+]i concentration in a concentration-dependent manner. The source of [Ca2+]i was extracellular as demonstrated by depletion of [Ca2+]i with EGTA. Furthermore, MOA caused activation of parietal cell protein kinase C (PKC). The effect of MOA upon PKC activation was [Ca2+]i-dependent but did not require phosphatidylserine as phospholipid co-factor. Similarly to the effect of diolein, MOA increased the stimulatory effect of phosphatidylserine at low [Ca2+]i concentrations. Treatment of parietal cells with MOA caused translocation of PKC from the cytosol to the membrane-associated cell fraction. We propose that MOA stimulates parietal cell acid secretion presumably by an increase of cytosolic free [Ca2+]i concentrations and PKC activation.

1-Methyl-3-isobutylxanthine↗

Calculation of left ventricular outflow tract area using three-dimensional echocardiography. Influence on quantification of aortic valve stenosis.

In 23 patients with aortic valve stenosis (14 male, 9 female, mean age 66 +/- 21.5 years) left ventricular outflow tract cross-sectional area was determined in planimetric fashion using three-dimensional echocardiography. The 3-D data-set for each patient had been acquired in the course of a multiplane transesophageal examination. Aortic valve area was determined using the continuity equation. Results obtained were compared to those calculated by continuity equation using to the conventionally determined LVOT area (a = pi [d/2]2). As reference method the results were compared to invasive measurements. 3-D planimetric determination of LVOT cross-sectional area was possible in 20 of 23 patients. In three patients, this method failed due to artefacts. The mean difference to the conventionally calculated LVOT area amounted to 0.18 cm2 (SD = 0.46). The comparison of AVA determined by continuity equation and by invasive measurement showed a mean difference of -0.074 cm2 (SD = 0.21) for the conventionally calculated LVOT area; for the planimetrically determined LVOT area the mean difference of AVA amounted to -0.03 cm2 (SD = 0.14) (p < 0.05). Planimetric determination of LVOT area using 3-D echocardiography improves the agreement of the continuity equation with invasive measurement.

Aged↗

Expression of matrix metalloproteinases in human glioma cell lines in the presence of IL-10.

Matrix metalloproteinases have been implicated to play a vital role in glioma invasion as they degrade extracellular matrix to facilitate the subsequent migration of tumor cells into the surrounding brain tissue. The cytokine Interleukin-10 (IL-10) was detected recently in glial tumors in vivo. Expression of specific IL-10 mRNA as well as blood serum levels of IL-10 in glioma patients increased with malignancy suggesting a functional role of IL-10 in glioma progression. Moreover, glioma cell migration in vitro was enhanced in the presence of IL-10. We therefore investigated the expression of the matrix metalloproteinases (MMPs) stromelysin-1 (MMP-3), 72-kDa collagenase (MMP-2), 92-kDa collagenase (MMP-9), matrilysin (MMP-7) and the human macrophage metalloelastase (MMP-12). In addition, a possible relation between exposure of glioma cells to IL-10 and invasiveness of these cells due to MMP expression was analyzed. Experiments with Matrigel coated Boyden chambers revealed a pronounced dose dependent effect of IL-10 on glioma invasiveness. The synthetic MMP-inhibitor Marimastat markedly reduced cell invasion in the Boyden chambers confirming the significance of MMPs in the process of invasion. Subsequently, the expression level of MMPs and the serine protease uPA was investigated in 7 glioma cell lines (U373, GaMG, U251, GHE, SNB19, U138 and D54) by RT-PCR. In all but one cell line no enhancement of MMP expression by IL-10 was detected. Matrilysin in U373 cells was the only protease found to be upregulated in the presence of IL-10 dependent on cell density. The present data suggest that IL-10 related effects on the invasive properties of the cell lines are not directly mediated by an upregulation of matrix metalloproteinase expression.

Brain Neoplasms↗

The Helicobacter pylori fatty acid cis-9,10-methyleneoctadecanoic acid stimulates protein kinase C and increases DNA synthesis of gastric HM02 cells.

Protein kinase C (PKC) has been implicated in the control of epithelial proliferative activity and in the process of malignant transformation. Helicobacter pylori (H.p.) infection is associated with increased gastric epithelial cell proliferation and has been linked with gastric carcinoma. In the present study, we report that the H.p. fatty acid cis-9,10-methyleneoctadecanoic acid (MOA) directly activates PKC (Ka 3.3 microM). The effect of MOA upon PKC activation was Ca2+ dependent but did not require phosphatidylserine as phospholipid cofactor. MOA increased the stimulatory effect of phosphatidylserine at low Ca2+ (1 microM) concentrations. These findings indicate that MOA interacts at the phospholipid- and the diacylglycerol-binding domain to elicit PKC activation. Treatment of gastric mucous cells HM02 caused translocation of PKC from the cytosol to the nuclear, mitochondrial and membrane fraction. Furthermore, MOA stimulated [3H]thymidine incorporation into the DNA of HM02 cells. Our results show that the H.p. fatty acid MOA activates PKC and increases DNA synthesis in gastric epithelial cells.

Animals↗

The 60 Minutes Myocardial Infarction Project. Characteristics on admission and clinical outcome in patients with reinfarction compared to patients with a first infarction.

PURPOSE: The purpose of the study was to evaluate parameters that characterize patients with myocardial reinfarction as compared to patients with a first infarction in clinical practice, and possibly to determine their clinical outcome. METHODS: The 60 minutes Myocardial Project is a German multicentre prospective observational study in which 136 hospitals are participating. Fourteen thousand, nine hundred and eighty consecutive patients with acute Q wave myocardial infarction were included from July 1992 to September 1994. RESULTS: Out of these 14,980 patients, there were 2854 (19%) with reinfarction and 12,126 (81%) with a first infarction. Patients with a reinfarction arrived at the hospital 24 min earlier than patients with a first infarction (pre-hospital delay 156 vs 180 min; P < 0.001); the door-to-needle time with reinfarction was longer (38 vs 30 min; P < 0.001); however, patients with reinfarction were older (69 vs 66 years; P < 0.001), had a lower rate of a diagnostic first ECG (54 vs 71%; P < 0.001) and received thrombolytic therapy less frequently than patients with a first infarction (46 vs 52%; P < 0.001). A low number of patients received primary PTCA ( n = 205) since only a few hospitals offered a primary PTCA service at the time the study was performed. In patients with reinfarction, there were more reasons as to why thrombolytic therapy was not given (24 vs 21%; P < 0.001). Left bundle branch block occurred more frequently in patients with reinfarction (15 vs 8%; P < 0.001). The intra-hospital course in patients with reinfarction was associated with an increase of complications and intra-hospital death (23 vs 15%; P < 0.001. CONCLUSIONS: Although reinfarction patients arrived earlier at hospital than patients with a first infarction, the former received thrombolytic therapy less frequently than the latter. Patients with reinfarction were older, more frequently had a non-diagnostic ECG on admission and had a higher rate of contraindications against thrombolytic therapy.

Adult↗

Sonography under Daylight Conditions.

PURPOSE: Gray scale image assessment in clinical ultrasound requires working in dim light or a dark room. Daylight conditions offer the advantage of shorter visual reaction time and enhanced visual perception. Look-up table manipulations could improve image brightness. MATERIALS AND METHODS: We investigated the possibility of brightness and contrast enhancement of coloured adaptive linear look-up tables (CALUT's) and their artifact resistance. Therefore under real-time conditions red/brown, green and blue CALUT's were calculated using the gray scale distribution (mean and standard deviation) of the actual image. The changes in contrast of several structural features (echo-poor and echogenic lesions, artifacts) were assessed by clinical investigators (n = 7). RESULTS: The CALUT's produced, independent of the original, images with constant brightness and contrast. Even under daylight conditions no artifacts appeared. Under scotopic conditions the red/brown CALUT's showed the best results compared to the unchanged image and the gray, green, and blue CALUT's. Hyper and hypoechoic differences with small contrast to the surrounding tissue are enhanced and can be detected more easily. CONCLUSION: Daylight sonography allows examination even in non-darkened rooms without loss of information. Eye adaptation to changing light conditions is no longer necessary; the offered image information is more suitable for the eye.

Algorithms↗

Intraoperative detection of malignant gliomas by 5-aminolevulinic acid-induced porphyrin fluorescence.

OBJECTIVE: Survival after surgery and radiotherapy for the treatment of malignant gliomas is linked to the completeness of tumor removal. Therefore, methods that permit intraoperative identification of residual tumor tissue may be of benefit. In a preliminary investigation, we have studied the value of fluorescent porphyrins that accumulate in malignant tissue after administration of a precursor (5-aminolevulinic acid) for labeling of malignant gliomas in nine patients. METHODS: Three hours before the induction of anesthesia, 10 mg 5-aminolevulinic acid/kg body weight was administered orally. Intraoperatively, red porphyrin fluorescence was observed with a 455-nm long-pass filter after excitation with violet-blue (375-440 nm) xenon light and was verified by analysis of fluorescence spectra. Fluorescing and nonfluorescing samples taken from the tumor perimeters were examined histologically or used to study the photobleaching of porphyrins by excitation light and white light from the operating microscope. Plasma and erythrocyte porphyrin levels were determined by fluorescence photometry. RESULTS: Normal brain tissue revealed no porphyrin fluorescence, whereas tumor tissue was distinguished by bright red fluorescence. For a total of 89 tissue biopsies, sensitivity was 85% and specificity was 100% for the detection of malignant tissue. For seven of nine patients, visible porphyrin fluorescence led to further resection of the tumor. Under operating light conditions, fluorescence decayed to 36% in 25 minutes for violet-blue light and in 87 minutes for white light. Plasma and erythrocyte porphyrin contents increased slightly, without exceeding normal levels. CONCLUSION: Our observations suggest that 5-aminolevulinic acid-induced porphyrin fluorescence may label malignant gliomas safely and accurately enough to enhance the completeness of tumor removal.

Aged↗