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Biomedical subjects

U Wegner

Publications and source records attributed to U Wegner.

33 records · Page 2Linked to original sources
PubMed1997

Adenovirus-receptor interaction with human lymphocytes.

Lymphocytes play a key role in cell-mediated immunity and are host cells for several viral and bacterial pathogens. Their importance in adenovirus (Ad) infections is not yet fully understood. The initial event, the attachment of Ad to lymphocytes and their subsets, was examined using flow cytometry. The study included analysis of stimulated T cells in binding assays with FITC-labeled Ad fiber. The results confirm that native peripheral lymphocytes express very small amounts of Ad receptors. Stimulation with PHA and interleukin 2 induced the expression. The presence of Ad DNA as a sign of internalization in stimulated cells was demonstrated using the polymerase chain reaction. The findings suggest that lymphocytes after stimulation can turn into target cells for Ad. This is particularly important if there are indications for persistence of Ad, and in the case of immunocompromised patients severe, life-threatening diseases can develop.

Adenoviruses, Human↗
PubMed1996

Ultrasound for diagnosis of apophyseal injuries.

Avulsion injuries of the apophysis is a problem in young athletes. A correct diagnosis is necessary for establishing the appropriate treatment and the rehabilitation program. However, it is often difficult to distinguish between a simple muscle strain and an avulsion fracture. The X-ray examination is helpful only when an ossification center of the apophysis exists. Ultrasonography is considered the suitable diagnostic tool for these cases. From June 1988 to June 1993, 243 young athletes were seen with an anamnestic and clinically suspected apophyseal injury of the lower extremity. In all cases X-ray examination and ultrasound examination were performed. In 80 cases the diagnosis was confirmed by X-ray examination and in 97 by ultrasonography. Four criteria were defined for the sonographic examination: (a) a hypoechogenic zone, (b) increased distance to the apophysis, (c) dislocation of the apophysis, and (d) mobility of the apophysis on dynamic examination. These criteria are correlated to (a) edema, (b) lysis, (c) avulsion, and (d) unstable avulsion of the apophysis. Ultrasonography is a proven technique for the detection of apophyseal injuries. In comparison to X-ray examination, it has the advantages of no radiation exposure, early detection even without ossification center, and dynamic examination.

Adolescent↗
PubMed1996

Fluorescent focus reduction assay for the screening of antiadenoviral agents.

A method for screening of antiviral compounds against adenoviruses was established. Test compounds were diluted and plated in chamber slides for tissue culture. Drug-treated, virus-infected cultures were stained with fluorescein isothiocyanate conjugated rabbit antibodies against adenovirus hexon type 2 and fluorescent cells were counted by microscopy. This assay is more sensitive than the colorimetric method and requires smaller volumes of compounds when compared with the standard method using plaque assay.

Adenoviruses, Human↗
PubMed1994

Functional characterization of a muscarinic receptor stimulating gastrin release from rabbit antral G-cells in primary culture.

In previous studies carbachol-induced stimulation of gastrin release from antral G-cells in primary culture suggested the presence of muscarinic acetylcholine receptors on this cell type. Therefore, we attempted to pharmacologically characterize the muscarinic acetylcholine receptor subtype involved. Enzymatically isolated rabbit antral mucosal cells (0.8% G-cells) were separated by counterflow elutriation yielding a fraction (1.7% G-cells) that was placed in culture on collagen-coated well plates. After 24-36 h of culture 13.0 +/- 2.4% of total adherent cells were immunoreactive for gastrin as shown by immunocytochemical staining using the avidin-biotin complex method. In this preparation basal gastrin release ranged from 3.3 +/- 0.3 to 4.1 +/- 0.3% of total cellular content. Maximal gastrin release in response to the acetylcholine receptor agonist carbachol (10(-4) M) or the selective muscarinic receptor agonist arecaidine propargyl ester (10(-4) M) was 8.5 +/- 0.4% and 7.6 +/- 0.4% of total cellular content, respectively. The EC50 values were 3.7 +/- 0.5 x 10(-6) M carbachol and 1.8 +/- 0.4 x 10(-6) M arecaidine propargyl ester. At a concentration of 10(-6) M the non-selective muscarinic receptor antagonist atropine and the muscarinic M3 receptor preferring antagonist hexahydro-sila-difenidol (HHSiD; M3 > or = M1 > M2) completely inhibited gastrin release in response to carbachol (Ki values: 52 x 10(-9) M atropine and 29 x 10(-9) M HHSiD) and arecaidine propargyl ester (Ki values: 11 x 10(-9) M atropine and 13 x 10(-9) M HHSiD).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Response of cellular antioxidants to ozone in wheat flag leaves at different stages of plant development.

The effect of ozone (O3) on growth, yield and foliar antioxidants of spring wheat (Triticum aestivum L. cv. Turbo) was investigated in 1990 and 1991 in Braunschweig, Germany. Plants were grown full-season in pots in open-top chambers ventilated with charcoal-filtered (CF) air to which one or two levels of O3 were added. Mean 8 h day(-1) (10.00-18.00 h) O3 concentrations in the CF and CF + O3 treatments were 5.9, 61.2 and 92.5 nl litre(-1) in 1990, and 4.7 and 86.4 nl litre(-1) in 1991. Plants that received the high O3 level showed symptoms of premature senescence of the oldest leaves and yield reductions in both growing seasons. The contents of ascorbate and glutathione and the enzyme activities of ascorbate peroxidase and glutathione reductase were measured in symptomless flag leaves in weekly intervals before and after the beginning of anthesis. Leaf age had a significant effect on all antioxidants investigated. The O3 exposures of about 90 nl litre(-1) increased the activity of ascorbate peroxidase and the concentration of glutathione, but there were no pollutant effects on ascorbate content and glutathione reductase activity. Measurements of the antioxidant levels throughout one day showed no clear indications of diurnal changes in the antioxidative capacity in wheat flag leaves. The results are discussed in relation to the role of antioxidants in O3 detoxification.

Journal Article↗
PubMed1993

[Stress reactions and stress fractures in the high performance athlete. Causes, diagnosis and therapy].

From 1987 until July 1991 70 athletes with stress reactions or stress fractures were treated in the orthopaedic department of the Hannover Medical School. The average age of the 42 male and 28 female athletes was 22.6 years. The number of athletes involved in track and field sports was 29 (41.4%), in gymnastics 9 (12.9%) and in soccer 5 (7.1%). The most common bone injured was the tibia in 29 (41.4%), followed by the tarsal navicular in 21 (30.0%), the midfoot in 17 (24.3%) and the fibula in 4 (5.7%) athletes. In three cases double stress fractures were found in adjacent locations; in one case a stress fracture of the opposite navicular occurred after the initial tarsal navicular stress fracture had healed, and in another case the tarsal navicular was found to be fractured again. Thirty-seven percent of the athletes claimed sudden increase in training intensity was the cause; 33% felt that the increased sprinting and jump activities were the reason for their complaints. In some athletes pain started after an ankle sprain. Standard diagnostic procedure consisted in X-rays in two planes and three-phase bone scanning. In tarsal navicular or tibial locations additional tomograms were performed. MRI and CT scans were reserved for unclear findings and to exclude the possibility of a tumorous or inflammatory process. A new grading system was introduced that covers all forms of stress reactions from periostitis to pseudarthrosis. Clinical symptoms, sport disabilities, radiological and bone scan findings were graded from A to D. Using a modified Wilson classification, all radiologically recognizable stress reactions could be classified.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Hemolytic anemia caused by echinocytosis in liver cirrhosis].

Severe haemolytic anaemia developed in a 34-year-old patient with histologically proven alcoholic liver cirrhosis. While in the blood smear there were only a few acanthocytes, under light-microscopy of EDTA-blood 70% of erythrocytes in the counting chamber were acanthocytes or echinocytes, a finding confirmed under the electromicroscope. It is likely that the echinocytosis and acanthocytosis were the cause of the haemolytic anaemia. Biochemical investigation of the lipid composition of the erythrocyte membrane and of plasma and of the apolipoproteins in plasma revealed a series of changes whose role in haemolysis is discussed.

Acanthocytes↗
PubMed1987

Effect of free radical scavengers and metal ion chelators on hydrogen peroxide and phenylhydrazine induced red blood cell lipid peroxidation.

Desferrioxamine a well-known iron chelator was found to decrease hydrogen peroxide and phenylhydrazine induced lipid peroxidation of red blood cell membranes assessed by hydrocarbon gas release and loss of polyunsaturated fatty acids. Hydroxyl radical scavengers like mannitol and thiourea and proteins like albumin were unable to reduce peroxidative reactions to our system. Addition of uric acid (in an unphysiological concentration of 5 mM) to the incubation medium resulted in a slight reduction in H2O2/phenylhydrazine mediated break-down of arachidonic (20:4) and docosahexaenoic acid (22:6) in the erythrocyte membrane and consequently in a decreased alkane release and haemolysis.

Alkanes↗
PubMed1985

Hyperglycemia in BALB/c mice after pretreatment with one subdiabetogenic dose of streptozotocin and subsequent infection with a Coxsackie B4 strain.

Male BALB/c mice were injected with one subdiabetogenic dose of streptozotocin followed by Coxsackie B4 virus infection 7 days later. The animals developed a transient hyperglycemia after streptozotocin-pretreatment and infection with a human Coxsackie B4 isolate. Frozen sections of pancreata stained with FITC-labeled antibodies showed an intensive infection of the exocrine tissue. Immunofluorescence studies with isolated islets obtained from streptozotocin-treated or untreated animals demonstrated virus antigen in about 20% of the islets 5 days after in vivo virus infection. It is supposed that the hyperglycemia measured in our experiments was caused by a cumulative effect of streptozotocin and virus infection.

Animals↗
PubMed1983

Characterization of pseudo-islets formed from pancreatic islet cell suspensions of neonatal rats.

Well-preserved pancreatic islet cell suspensions were prepared from islets of Langerhans of neonatal rats by gentle trypsin treatment. Within a culture period of 4-6 days the islet cells reaggregate spontaneously and form pseudo-islets of different size and of a variable insulin content. While the ratio of insulin to glucagon in isolated islets of Langerhans is constant (18 +/- 1.9), the hormone ratio of the pseudo-islets is strongly variable and increased, indicating an excess of insulin. Glucose enhancement from 1.5 mmoles/l to 15 mmoles/l results in a significant stimulation of (pro)insulin biosynthesis whereas insulin secretion of the pseudo-islets is only slightly increased. At high glucose concentration (15 mmoles/l) insulin secretion of the pseudo-islets can be potentiated (by a factor of 4.5 +/- 0.46) by 3-isobutyl-l-methylxanthine (IBMX). Compared with the initial islet cell suspension, the cell aggregation during pseudo-islet formation did not result in an enhanced secretory response on glucose stimulation.

Animals↗
PubMed1982

Pancreatic islet cell suspensions of newborn rats and the formation of pseudo-islets in culture.

Well preserved pancreatic islet cell suspensions were isolated by trypsin treatment from islets of Langerhans of newborn rats. (Pro)insulin biosynthesis of freshly isolated islet cells can be stimulated by increasing glucose concentrations. In contrast insulin secretion on glucose as the only stimulus is drastically reduced but can be potentiated by 3-isobutyl-1-methylxanthine (IBMX). Within a period of 4-6 days in tissue culture pancreatic islet cells of newborn rats show the tendency to aggregate and form pseudo-islets of different size.

1-Methyl-3-isobutylxanthine↗