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Biomedical subjects

S Wagner

Publications and source records attributed to S Wagner.

At least 37 records · Page 2Linked to original sources
PubMed2004

[Reduction of technology fears in psychosomatic rehabilitation--concepts and results based on a computer training for older employees].

A computer training program was developed specifically oriented toward middle-aged employees, their learning needs and their computer-related fears. This program was based on a pilot study showing a high degree of stresses associated with the introduction of computer technology at the workplace in this age group (50-59 years). A survey of 623 patients confirmed that these persons experienced technological change predominantly as disadvantageous or threatening. Based on 114 patients, concepts and results of the computer training are presented. Participation reduced avoidance behaviors, fears and increased interest and initiative based both on the patients' and their trainers' perspectives.

Attitude to Health↗
PubMed2004

Assessment of left ventricular volumes and function: intraindividual comparison of multi-slice spiral CT and electron beam CT in an animal model.

PURPOSE: To evaluate multi-slice spiral computed tomography (MSCT) for measurements of left ventricular volumes, ejection fraction (EF), and myocardial mass in comparison with electron beam CT (EBCT) as a reference method. MATERIAL AND METHODS: Six minipigs underwent both standardized contrast-enhanced MSCT (effective acquisition time per cardiac cycle 125.7+/-30.1 ms, reconstructed slice thickness 8 mm) and EBCT (acquisition time 50 ms, collimated slice thickness 8 mm). The contrast-to-noise ratio of the left ventricle was measured in each animal, and the contour sharpness of the myocardium was analyzed. Volumes (EDV, ESV, SV) ejection fraction (EF), and muscle mass were calculated by MSCT and by EBCT using the slice summation method. RESULTS: MSCT had a higher contrast-to-noise ratio and delineated the myocardial contours more sharply than EBCT. There was a close linear correlation between both modalities for all parameters (EDV: rP=0.88, ESV: rP=0.91, SV: rP=0.85, EF: rP=0.93; mass: rP=0.90; P<0.05 each). MSCT slightly overestimated ESV and slightly underestimated SV and EF compared with EBCT (P<0.05 each). CONCLUSIONS: Image quality in MSCT is superior to that of EBCT. Functional parameters correlate well between both modalities, but the accuracy of MSCT is limited by its lower temporal resolution.

Animals↗
PubMed2004

Valproic acid induces differentiation of a supratentorial primitive neuroectodermal tumor.

In preclinical models the antiepileptic drug valproic acid induces differentiation of neoplastic cells, representing an evolving anticancer approach that takes into account that malignant cells resemble immature progenitor cells capable of terminal differentiation. The authors report on a child suffering from a relapsing supratentorial primitive neuroectodermal tumor that received valproic acid for epilepsy treatment over 7 months before the relapse. In contrast to the initial tumor, the relapsing tumor showed glial differentiation and low proliferation index. This is the first report of a relapsed supratentorial primitive neuroectodermal tumor that shows histologically confirmed signs of tumor cell differentiation induction.

Cell Differentiation↗
PubMed2004

Assessment of the biological performance of the needle-free injector INJEX using the isolated porcine forelimb.

BACKGROUND: The development and utilization of novel needle-free injection devices in order to minimize needle stick injuries make increasing demands for suitable assay systems, which reflect the physiological situation in humans as close as possible. OBJECTIVES: It was therefore the goal of the present study to test the biological performance of a needle-free injector (INJEX) by the use of porcine skin as a model with a high predictive value for the feasibility in humans because of its close similarity to human skin. METHODS: In order to use porcine skin in the context of the underlying tissues, the isolated porcine forelimb was chosen as an assay model for use with the INJEX injector. Ink or the fluorescent dye fluorescein-isothiocyanate was injected and the penetration depth was determined metrically and dye distribution histologically. To assess the resorption of heparin, needle injection was compared with needle-free injection in a perfused limb model. RESULTS: Increasing amounts of ink increasingly penetrated into subcutaneous tissue layers in a cone-shaped manner mainly following lead structures. Penetration was hampered by skin thickness and by the deep muscle fascia, which served as a penetration barrier. Resorption of heparin was similar irrespective of injection by the use of a needle or the INJEX device. CONCLUSIONS: The isolated porcine forelimb serves as a versatile tool for the assessment of the biological performance of needle-free injection devices such as INJEX. Further studies are necessary to correlate the model for drug delivery in humans.

Absorption↗
PubMed2004

Characterization of cross-reactive bell pepper allergens involved in the latex-fruit syndrome.

BACKGROUND: Between 30% and 50% of individuals who are allergic to latex products are also allergic to specific plant foods, a fact that is well documented as the latex-fruit syndrome. Simultaneous sensitization to latex and bell pepper has been previously reported. Although bell pepper fruits are frequently consumed raw, cooked or as a spice, little is known about the cross-reactive allergens. OBJECTIVE: In this study we wished to identify bell pepper allergens involved in the latex-fruit syndrome. METHODS: Sera of four patients who displayed clinical symptoms to latex and bell pepper were used in immunoblot studies on protein extracts of three different cultivars of fresh bell pepper and fresh Hevea latex. Cross-reactive allergens were identified by inhibition experiments using recombinant Hev b 8 (latex profilin), and natural Hev b 2 (latex beta-1,3-glucanase) in addition to the protein extracts. A novel cross-reactive IgE-reactive 30 kDa protein was subjected to sequence analysis. RESULTS: Three patients displayed IgE to profilins from bell pepper fruits and latex. Two patients possessed IgE to Hev b 2, a latex beta-1,3-glucanase, and a homologous protein in bell pepper. One patient possessed IgE reactive with a protein of 30 kDa identified by N-terminal sequencing as an l-ascorbate peroxidase and another patient to a protein of 38 kDa. Additionally, IgE binding proteins in two higher molecular weight ranges showed cross-reactive capacities. CONCLUSION: Our findings show on the molecular level that bell pepper is part of the latex-fruit syndrome. For the first time we have identified the major latex allergen Hev b 2, a beta-1,3-glucanase, and the bell pepper l-ascorbate peroxidase as cross-reactive allergens. We were also able to show that profilins are responsible for some of the IgE cross-reactivity.

Adult↗
PubMed2004

Morphosyntax, prosody, and linking elements: the auditory processing of German nominal compounds.

The morphosyntactic decomposition of German compound words and a proposed function of linking elements were examined during auditory processing using event-related brain potentials. In Experiment 1, the syntactic gender agreement was manipulated between a determiner and the initial compound constituent (the ''nonhead'' constituent), and between a determiner and the last constituent (''head''). Although only the head is (morpho)syntactically relevant in German, both constituents elicited a left-anterior negativity if its gender was incongruent. This strongly suggests that compounds are morphosyntactically decomposed. Experiment 2 tested the function of those linking elements which are homophonous to plural morphemes. It has been previously suggested that these indicate the number of nonhead constituents. The number agreement was manipulated for both constituents analogous to Experiment 1. Number-incongruent heads, but not nonhead constituents, elicited an N400 and a subsequent broad negativity, suggesting that linking elements are not processed as plural morphemes. Experiment 3 showed that prosodic cues (duration and fundamental frequency) are employed to differentiate between compounds and single nouns and, thereby, between linking elements and plural morphemes. Number-incongruent words elicited a broad negativity if they were produced with a single noun prosody; the same words elicited no event-related potential effect if produced with a compound prosody. A dual-route model can account for the influence of prosody on morphosyntactic processing.

Adult↗
PubMed2003

[Prosthetic pyelovesical and pyelocutanous bypass. A palliative therapy concept in tumor-induced chronic hydronephprosis].

MATERIALS AND METHODS: Since 2/02 to 2/03 a total of 13 patients underwent either pyelovesical bypass (10 patients) or pyelocutaneous bypass (3 patients). A composite implant, consisting of two coaxial tubes internal pure smooth silicone covered by coiled e-PTFE has been designed to serve as the ureteral replacement. This prothesis in inserted percutaneously into the renal pelvis, tunnelled subcutaneously, and introduced through a small suprapubic incision in the bladder or out directly through a cutaneous orifice. RESULTS: One encrustation of the subcutaneous pyelocutaneous bypass was observed, no angulation or dislocation during a mean follow up of 6.2 month. Improvement in the quality of life was stressed in all patients. CONCLUSIONS: The subcutaneous urinary division using a silicone-PTFE prothesis is an efficient and minimal-invasive technique to attend malignant obstructions of the ureter.

Aged↗
PubMed2003

[Acute pancreatitis].

While interstitial acute pancreatitis usually takes a benign course, necrotizing acute pancreatitis takes a severe course, mainly because of severe local and systemic complications. After a quick diagnosis it is necessary to rapidly assess a degree of severity of the disease and thus the prognosis. The clinical picture and the result of imaging procedures do not always correspond. The management basically includes to treat pain as well as to administer fluid, electrolyte, protein and calories. In addition, systemic treatment of complications such as shock or respiratory and renal insufficiency--if occurring--is necessary. In case of pancreatic necrosis, prophylactic administration of pancreas-penetrable antibiotics is recommended to avoid infection. In the severely ill with infected pancreatic necrosis, surgery is the treatment of choice. In approximately 10% of all patients with alcohol-induced pancreatitis, there is a gradual transition to chronic pancreatitis.

APACHE↗
PubMed2003

[Experimental microvascular and clotting changes--significance for acute stroke therapy].

Ischemia and reperfusion cause significant alterations in the structure and functional integrity of the cerebral microvasculature. Clinical sequelae include cerebral oedema, haemorrhagic transformation with the extravasation of cellular blood elements, and possible parenchymal haemorrhage. Vascular changes originate from structural changes of the vascular wall and from interactions with blood components such as leukocytes. This leads to the activation of various pathophysiological cascades including the clotting system, its inhibitors,matrix metalloproteases, and serine proteases. This article focuses on the degradation of the microvascular basal lamina, which is formed by extracellular matrix proteins such as type IV collagen, fibronectin, and laminin. Extracellular matrix proteins are degraded by matrix metalloproteases and serine proteases. Tissue plasminogen activator (t-PA), a serine protease commonly administered for thrombolysis, activates matrix metalloproteinases in turn, amplifying local proteolytic activity. Clinical implications and possible therapeutic strategies are discussed.

Animals↗
PubMed2003

Early osteoarthritic changes of human femoral head cartilage subsequent to femoro-acetabular impingement.

OBJECTIVE: To use the surgical samples of patients with femoro-acetabular impingement due to a nonspherical head to analyze tissue morphology and early cartilage changes in a mechanical model of hip osteoarthritis (OA). DESIGN: An aberrant nonspherical shape of the femoral head has been assumed to cause an abutment conflict (impingement mechanism) of the hip with subsequent cartilage lesions of the acetabular rim and surface alterations of the nonspherical portion of the head. In this study, 22 samples of the nonspherical portions of the head have been obtained during hip surgery from young adults (mean 30.4 years, range 19-45 years) with an impingement conflict. The samples were first compared with tissue from the same area obtained from six age-matched deceased persons (control group) with normal hip morphology and second with cartilage from 14 older patients with advanced OA. All samples were characterized histologically and hyaline cartilage was graded according to the Mankin criteria. They were further subjected to examination on a molecular basis by immunohistology for cartilage oligomeric matrix protein (COMP), tenascin-C and a collagenase cleavage product (COL2-3/4C(long)) and by in situ hybridization for collagen type I and collagen type II. RESULTS: All samples from the patient group revealed hyaline cartilage with degenerative signs. According to the Mankin criteria, the cartilage alterations were significantly different when compared with the control group (p=0.007) but were less distinct when compared with cartilage from patients with advanced OA (p=0.014). Positive staining and distribution pattern for COMP, tenascin-C and COL2-3/4C(long) showed similarities between the samples from the impingement group and osteoarthritic cartilage but they were distinctly different when compared with healthy cartilage. Levels of collagen I and II transcripts were upregulated in 6 and 10, respectively, of the 14 samples with OA and in 9 and 12, respectively, of the 22 samples from the impingement group. None of the samples from the control group showed upregulation of Collagen I and II mRNA. CONCLUSIONS: The aberrant nonspherical portion of the femoral head in young patients with an impingement conflict consists of hyaline cartilage which shows clear degenerative signs similar to the findings in osteoarthritic cartilage. The tissue alterations are distinctly different when compared with a control group, which substantiates an impingement conflict as an early mechanism for degeneration at the hip joint periphery.

Adult↗
PubMed2003

[MR angiography of the coronary arteries: comparison of the blood pool contrast medium Gadomer and Gd-DTPA in pigs].

AIM: To investigate the signal-enhancing effects of the macromolecular contrast medium Gadomer in MR angiography of the coronary arteries compared to Gd-DTPA. MATERIAL AND METHODS: A total of 15 MRI examinations of the heart were performed in pigs at 1.5 T using a pulse-triggered, segmented 3D FLASH sequence with data acquisition during breathhold before and up to 30 min after contrast medium injection. Gadomer was investigated at two doses (0.05 and 0.1 mmol Gd/kg), Gd-DTPA at one (0.3 mmol Gd/kg) (n = 5 examinations per dose). Standard sequences without magnetization preparation were supplemented by sequences with magnetization saturation applied before data acquisition before and immediately after contrast medium injection. Analysis comprised quantitative determination of blood and myocardium signal to noise (S/N) and contrast to noise (C/N) and qualitative assessment of several parameters of image quality and coronary artery visualization. RESULTS: Gadomer leads to a significant C/N increase between blood and myocardium compared to the unenhanced examination and the increase is longer-lasting than that produced by Gd-DTPA (Gd-DTPA: only directly after injection; Gadomer: up to 5 min post injection at 0.05 mmol Gd/kg, up to 10 min at 0.1 mmol Gd/kg). The qualitative evaluation shows that visualization of the coronary arteries and branch vessels is significantly better with Gadomer at both doses than with Gd-DTPA. Magnetization saturation increases the C/N in combination with Gd-DTPA and at the higher dose of Gadomer with the latter producing a higher increase in C/N values. CONCLUSION: Gadomer is a suitable contrast medium for MR angiography of the coronary arteries with the dose of 0.1 mmol Gd/kg being superior to 0.05 mmol Gd/kg due to a longer imaging window.

Animals↗
PubMed2003

Procalcitonin as a diagnostic tool in lower respiratory tract infections and tuberculosis.

The diagnostic significance of procalcitonin concentrations in lower respiratory tract infections and tuberculosis is not known. A prospective analysis was, therefore, performed in patients with acute exacerbation of chronic bronchitis (AECB), community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and tuberculosis and their procalcitonin levels compared with those of patients with noninfectious lung diseases (controls). In addition, standard inflammatory parameter data were collected. A prospective clinical study was performed with four different groups of patients and a control group that consisted of patients with noninfectious lung diseases. A total of 129 patients were included: 25 with HAP, 26 CAP, 26 AECB, 27 tuberculosis, and 25 controls. C-reactive protein level, blood cell counts and procalcitonin concentration were evaluated on the first day after onset of clinical and inflammatory symptoms prior to treatment. The median procalcitonin concentrations in HAP, CAP, AECB and tuberculosis were not elevated in relation to the cut-off level of 0.5 ng x mL(-1). In the HAP group, in four of five patients who subsequently died, procalcitonin concentrations of >0.5 ng x mL(-1) were found. In acute lower respiratory infections, such as HAP, CAP and AECB, significantly elevated levels were found in comparison to the control group, but below the usual cut-off level. No differences were observed between tuberculosis and the control group. Relative to the current cut-off level of 0.5 ng x mL(-1), procalcitonin concentration is not a useful parameter for diagnosis of lower respiratory tract infections. However, compared to the control group, there were significantly elevated levels in patients with hospital-acquired pneumonia, community-acquired pneumonia and acute exacerbation of chronic bronchitis below the current cut-off level, which should be further investigated.

Acute Disease↗
PubMed2002

Treatment of disseminated ocular melanoma with sequential fotemustine, interferon alpha, and interleukin 2.

Malignant melanoma of the uvea is remarkable for purely haematogenous dissemination and its tendency to metastasise to the liver. Although the liver is involved in up to 95% of patients, 50% of these also develop extrahepatic metastases, most often in the lungs, bone, skin, and brain. The only effective treatments reported to date relied on hepatic arterial chemoembolisation or -perfusion. The objective of this study was to establish a therapy protocol addressing patients with both sole liver involvement and systemic disease. Forty-eight patients with metastatic ocular melanoma received fotemustine 100 mg m(-2) either as 60-min infusion into the hepatic artery or as 15-min infusion via a peripheral vein, depending on the metastatic sites involved, i.e., restriction to the liver or hepatic together with extrahepatic disease. For the first treatment cycle this infusion was repeated after one week. For all cycles, subsequent to a three week resting period, patients received an immunotherapy consisting of subcutaneous interleukin 2 and interferon alpha(2). Although objective responses were more frequent within the cohort receiving intraarterial fotemustine (21.7 vs 8%), this difference did not translate into a significant benefit in overall survival, i.e., 369 and 349 days, respectively. Of note, this overall survival is much longer than that repeatedly reported for stage IV uveal melanoma not treated with fotemustine, suggesting a therapeutic activity of this cytostatic drug even after systemic administration.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

The latex-fruit syndrome.

Approximately 30-50% of individuals who are allergic to natural rubber latex (NRL) show an associated hypersensitivity to some plant-derived foods, especially freshly consumed fruits. This association of latex allergy and allergy to plant-derived foods is called latex-fruit syndrome. An increasing number of plant sources, such as avocado, banana, chestnut, kiwi, peach, tomato, potato and bell pepper, have been associated with this syndrome. The prevailing hypothesis is that allergen cross-reactivity is due to IgE antibodies that recognize structurally similar epitopes on different proteins that are phylogenetically closely related or represent evolutionarily conserved structures. Several types of proteins have been identified to be involved in the latex-fruit syndrome. Two of these are plant defence proteins. Class I chitinases containing an N-terminal hevein-like domain cross-react with hevein (Hev b 6.02), a major IgE-binding allergen for patients allergic to NRL. A beta-1,3-glucanase was identified as an important latex allergen which shows cross-reactivity with proteins of bell pepper. Another important NRL allergen, Hev b 7, is a patatin-like protein that shows cross-reactivity with its analogous protein in potato. Furthermore, patients with allergy to plant-derived foods and associated pollinosis show a high frequency of IgE reactivity to the pan-allergen profilin, which may cause positive serum IgE determinations to NRL. Although there is much information about the plant-derived foods and some data about the allergens involved in the latex-fruit syndrome, it is not always clear whether latex sensitization precedes or follows the onset of food allergy.

Antimicrobial Cationic Peptides↗
PubMed2002

Mucosal tolerance as therapy of type I allergy: intranasal application of recombinant Bet v 1, the major birch pollen allergen, leads to the suppression of allergic immune responses and airway inflammation in sensitized mice.

BACKGROUND: Several studies have demonstrated that mucosal administration of soluble antigens can prevent the onset or reduce the severity of certain autoimmune diseases or allergies. Few studies exist showing the efficacy of mucosal tolerance for therapy of such diseases. OBJECTIVE: The aim of the present study was to modulate an allergic immune response by intranasal antigen administration in an already sensitized organism. METHODS: A murine model of allergic asthma to birch pollen (BP) and its major allergen Bet v 1 was utilized. Sensitized mice were intranasally treated with recombinant (r)Bet v 1 in different concentrations and at different intervals. On the day the mice were killed, blood and bronchoalveolar lavage fluids were taken and immediate type I skin tests were performed. T cell proliferation and cytokine production (interleukin (IL)-5, interferon (IFN)-gamma) were measured in spleen and lung cell cultures. RESULTS: Mucosal treatment with rBet v 1 (3 x 50 microg in 4 day intervals) led to a reduction of type I skin reactions, suppressed immunoglobulin (Ig)G1/IgE antibody levels and markedly decreased IL-5 and IFN-gamma production in vitro in spleen and lung cell cultures. Moreover, lung inflammation (i.e. eosinophilia and IL-5 levels in bronchoalveolar lavage fluids) was significantly suppressed by the treatment. CONCLUSION: Our results demonstrate that intranasal treatment with rBet v 1 reduced systemic allergic immune responses as well as airway inflammation in BP-sensitized mice. We therefore suggest that mucosal tolerance induction with recombinant allergens could be a promising concept for the therapy of allergic diseases.

Administration, Intranasal↗
PubMed2002

The assessment of the frequency of chews during rumination enables an estimation of rumination activity in hay-fed sheep.

The objective was to assess rumination behaviour and, more specifically, the intra-individual and inter-individual variation of the frequency of chews during rumination (per min) in five Blackhead sheep fed hay at a level of 100% maintenance (experimental period [EP] I), 50% maintenance (EP II) and ad libitum (EP III). Animals ruminated in EP II less (416 min/day) than in EP I and III (558 and 592 min/day, respectively). Mean inter-individual coefficients of variation (CV) of frequency (defined as number of chews/duration of chewing per cycle) were 12.5%, mean intra-individual CV were 2.5%. The respective CVs for the duration of rumination per day were 8.1 and 9.7%, respectively. The level of intake influenced the frequency of chews significantly. It is concluded that the frequency of chews has to be considered in studies investigating chewing behaviour of ruminants. Under the experimental conditions investigated, number of chews during rumination per day could be estimated by the frequency of chewing with nearly the same precision as by using the duration of rumination per day.

Animal Feed↗
PubMed2002

Significance of the caspase family in Helicobacter pylori induced gastric epithelial apoptosis.

BACKGROUND AND AIMS: H. pylori infection results in an increased epithelial apoptosis in gastritis and duodenal ulcer patients. We investigated the role and type of activation of caspases in H. pylori-induced apoptosis in gastric epithelial cells. METHODS: Differentiated human gastric cancer cells (AGS) and human gastric mucous cell primary cultures were incubated with H. pylori for 0.5-24 hours in RPMI 1640 medium, and the effects on cell viability, epithelial apoptosis, and activity of caspases were monitored. Apoptosis was analyzed by detection of DNA-fragments by Hoechst stain(R), DNA-laddering, and Histone-ELISA. Activities of caspases were determined in fluorogenic assays and by Western blotting. Cleavage of BID and release of cytochrome c were analyzed by Western blot. Significance of caspase activation was investigated by preincubation of gastric epithelial cells with cell permeable specific caspase inhibitors. RESULTS: Incubation of gastric epithelial cells with H. pylori caused a time and concentration dependent induction of DNA fragmentation (3-fold increase), cleavage of BID, release of cytochrome c and a concomittant sequential activation of caspase-9 (4-fold), caspase-8 (2-fold), caspase-6 (2-fold), and caspase-3 (6-fold). No effects on caspase-1 and -7 were observed. Activation of caspases preceded the induction of DNA fragmentation. Apoptosis could be inhibited by prior incubation with the inhibitors of caspase-3, -8, and -9, but not with that of caspase-1. CONCLUSIONS: Activation of certain caspases and activation of the mitochondrial apoptotic pathway are essential for H. pylori induced apoptosis in gastric epithelial cells.

Apoptosis↗