PubMed Health⌕ Search

Biomedical subjects

W Baumann

Publications and source records attributed to W Baumann.

At least 19 recordsLinked to original sources
PubMed1994

[Biomechanical stress analysis of the lower extremity].

Within the field of prevention and rehabilitation, a detailed knowledge of the internal stresses and strains, for example the forces acting on and within joints, muscular force, is desirable or indispensable. The complex analysis of movements described here is based on a biomechanical model that takes into account the results of research done by F. Pauwels showing that muscular activity helps reduce the loading of tubular bones. The principle of functional adaptation provides a reasonable explanation for the "muscular redundence" of the locomotory system, and forms the basis for the calculation of internal loads. The results of the analysis include muscular and joint forces and the stresses within femur and tibia. The required anatomical data were for the most part obtainable directly from the test subject by magnetic resonance imaging. The calculated muscular forces are in good agreement with EMG measurements.

Biomechanical Phenomena↗
PubMed1992

[Stress on the upper ankle joint in tennis-specific forms of movement].

The permanently increasing number of injuries in tennis, which are mainly located at the lower extremity, indicates that the internal load e.g. applicated to the ankle during certain movements might be a critical factor. In the present study the relationship between calculated ankle load and muscle forces appearing during tennis techniques performed in a laboratorial setup and some varying parameters such as playing surface, footwear and individual differences in movement structure were investigated. It could be shown that on a felt tennis floor due to its frictional characteristics the midfootstriking subject produced the highest ankle load, while the heelstriking technique reduces the load as well as the change of the playing surface to a floor with loose granulate. In addition it should be considered that external forces (e.g. gained from a force plate) must not be used as predictors for internal load. The presented data show that the model-aided load calculation (MALC) from two trials with similar ground reaction forces leads to completely different values of e.g. the ankle-joint force.

Ankle Injuries↗
PubMed1991

[Comparison of the bioequivalence of two allopurinol preparations].

Allopurinol generally is considered to be a problematic substance as to its bioavailability. To prove the quality, the in-vivo bioequivalence of an allopurinol (CAS 315-30-0) preparation (Cellidrin 300) in comparison to the standard preparation has been investigated. Both products were bioequivalent with regard to all relevant parameters such as AUC, tmax and Cmax.

Adult↗
PubMed1991

[Hepatitis B virus DNA. Current diagnosis in children with chronic hepatitis B].

After cloning the hepatitis B virus genome molecular hybridization techniques have been established for detection of HBV-DNA in serum and liver tissue. HBV-DNA is presently the most sensitive marker of viral replication and infectivity, which was previously related to the presence of HBeAg in serum and HBcAg in liver cells. HBV-DNA is usually analysed by dot blot-, Southern blot- and in situ hybridization techniques. The study of HBV-DNA has become a valuable part of the routine diagnostic in chronic hepatitis B, providing a more reliable estimation of viral replication and contagiousness and better parameters for severity and prognosis of the chronic infection.

Blotting, Southern↗
PubMed1990

Cellular cytotoxicity against autologous hepatocytes in children with different forms of chronic hepatitis B.

Cell-mediated immune reactions play the most important role in the pathogenesis of chronic viral and auto-immune hepatitis. Cellular cytotoxicity (CC) of peripheral blood lymphocytes against autologous hepatocytes isolated from liver biopsies was studied in 29 children with different types of hepatitis B surface antigen (HBsAg)-positive hepatitis. Children with chronic hepatitis B showed higher cytotoxicity than control patients. However, a correlation of cytotoxicity to serum amino-transferases, HBeAg-/Anti-HBe-status, and hepatitis B virus DNA in serum could not be found. Children with a higher percentage of hepatitis B core antigen (HBcAg) expression in their liver tissue presented lower CC values, and vice versa. This supports the hypothesis that virus elimination occurs via T-cell attack against HBcAg expressing hepatocytes. Furthermore, children with a longer duration of chronic hepatitis B had considerably higher cytotoxicity values. Possibly, CC plays a role in perpetuating liver damage after infection with hepatitis B virus.

Adolescent↗
PubMed1990

Diagnostic significance of epithelioid granulomas in Crohn's disease in children. Multicenter Paediatric Crohn's Disease Study Group.

Out of 528 children with Crohn's disease in a Multicenter Paediatric Crohn's Disease Study Group, 37 cases had epithelioid granulomas but did not fulfill defined radiographic criteria of the disease. Follow-up studies including clinical, biochemical, radiological, endoscopic, and histological investigations were done in these patients. Initially, all patients showed clinical symptoms and 27 of them had biochemical signs of chronic inflammation. After a mean follow-up of 3 years, all 37 children treated for Crohn's disease got a complete upper gastrointestinal series with small bowel followthrough and 8 children in addition had barium enemas. Colonoscopies were done in 23 patients. Radiographic examination revealed Crohn's disease in 14 and endoscopy additionally confirmed Crohn's disease in 8 further cases. One child was diagnosed as having chronic granulomatous disease. Thirteen children still remained unclassified after these follow-up studies including radiographs and endoscopy. An interval of 3 years may in some cases be too short to express the complete radiographic pattern of Crohn's disease. Our studies demonstrate that in addition to initial radiological, endoscopic, and histological investigations, a thorough follow-up is necessary in early diagnosed patients. In these children, epithelioid granulomas are of high diagnostic validity preceding radiological changes of Crohn's disease often for years.

Adolescent↗
PubMed1990

Defective jejunal brush border membrane sodium/proton exchange in association with lethal familial protracted diarrhoea.

The spectrum of clinical disease associated with specific defects in jejunal brush border membrane sodium/proton exchange is poorly defined and only two patients have been described so far. Jejunal brush border membrane transport studies were performed in a boy who presented with lethal familial protracted diarrhoea in the first few days of life. Using jejunal brush border membrane vesicles prepared from conventional jejunal biopsy specimens, initial sodium uptake under H+ gradient conditions was found to be only 6% of the mean control value. In contrast, sodium stimulated glucose uptake was normal. Our data confirm the importance of a congenital defect in this exchanger as a cause of severe sodium-losing diarrhoea and extend the spectrum of disorders characterised by a specific defect in brush border membrane Na+/H+ exchange to include some forms of lethal familial protracted diarrhoea.

Biological Transport, Active↗
PubMed1990

[Hepatitis A, B, CMV, EBV and HIV infections in premature and term newborn infants following polytransfusion].

306 children who received polytransfusion or exchange transfusion between 1979 and 1983 and 104 age-matched controls were re-examined at a median age of 2.9 years for hepatitis A and B, CMV, EBV, and HIV infections. This retrospective study revealed no differences between transfused children and controls. HBsAg and anti-HIV were not detected. Two children were suspected of having hepatitis C. In both groups the incidence of positive CMV and EBV serologies was significantly increased in children from Mediterranean countries. Red cell concentrates were less frequently associated with CMV infection. These results confirm the exclusive recruitment of volunteer donors from a "healthy", mainly rural population and support the preferred use of red cell concentrates in paediatric patients.

Antibodies, Viral↗
PubMed1990

[Congenital intracranial teratoma with exophthalmos].

We report the rare case of a term newborn with an excessively large congenital, intracranial teratoma expanding into the right orbita and maxilla. The main symptoms were a total unilateral exophthalmos, a tumorous mass in the right cheek, macrocephaly with wide sutures, and a bulging fontanel. The diagnosis was confirmed by sonography, computed tomography and an exploratory excision from the retromaxillary region.

Brain↗
PubMed1989

Histologic features in autoimmune hepatitis.

In order to see if the term of "plasma cell hepatitis", dating back to the early sixties, is still valid as a morphological diagnosis for autoimmune chronic hepatitis (AICH), and to find out if the existence of several subgroups is reflected by histopathology, we investigated 26 patients with chronic hepatitis, who met the criteria of autoimmune hepatitis based on tests for antinuclear, anti-smooth muscle antibodies (SMA) and on immunoassays for liver-kidney-microsomal (LKM) antigen, liver membrane antigen (LMA), and soluble liver antigen (SLA). In our material autoimmune hepatitis represent the entire spectrum of chronic hepatitis with variable inflammatory activity ranging from chronic persistent hepatitis to severe inflammatory lesions in chronic active hepatitis with transition to cirrhosis. When compared to viral chronic hepatitis A and non-A, non-B, however, characteristic features can be evaluated consisting in broad hypocellular areas of collapse and microacinar transformation of hepatocytes with hydropic swelling being the predominant type of cell lesion. Eosinophilic clumping and acidophilic necrosis were insignificant. Plasma cells were not a constituent feature of AICH. From this histopathologic pattern it may be concluded that the disease seems to run a sluggish course in most patients, however, in few cases a dramatic development may determine the disease with fatal acute episodes which are terminated by death or fade into slow progression. The different subgroups could not be distinguished by histopathology.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Cleavage and synthesis of sialic acids with aldolase. NMR studies of stereochemistry, kinetics, and mechanisms].

1H-NMR spectroscopy was used to study cleavage and synthesis of N-acetyl- and N-glycoloyl-D-neuraminic acid by Clostridium perfringens aldolase. Whereas the alpha-anomers of Neu5Ac and Neu5Gc serve as substrate in the cleavage reaction, alpha-ManNAc and alpha-ManNGc are its primary products. The same alpha-anomers are needed by the aldolase for the synthesis of Neu5Ac and Neu5Gc. During the enzyme reaction in D2O both H-atoms at C-3 of Neu5Ac are exchanged by deuterium, H-3e reacting faster than H-3a. Rate constants and concentrations at equilibrium of reactants are temperature- and pH-dependent: The amount of Neu5Ac in equilibrium increases with decreasing temperature and increasing pH-value. Based on these results a mechanism of aldolase action is discussed.

Clostridium perfringens↗
PubMed1989

Isolation of unusually composed sialyl-compounds from hemofiltrate.

Sialyl compounds are essential components of various biological fluids but relatively little is known about their occurrence in the extracellular fluid of patients with end-stage renal disease. As we have developed a macropreparative method for concentrating and desalting a wide range of fractions from diluted biological fluids we have been able to isolate and identify 5 sialooligosaccharides, 3 sialosugarphosphates, 2 monosialoglycopeptides and 1 disialoglycopeptide. The structures have been elucidated predominantly by one and two-dimensional NMR spectroscopy, enzymatic degradation and FAB mass spectrometry. The accumulation of these compounds in uremic sera may be of particular interest as they may interact in the molecular biology of diseases typically associated with the uremic state, e.g., immune deficiency, neurological disorders, receptor binding abnormalities, complement system disturbances and cell membrane alterations.

Carbohydrate Conformation↗
PubMed1987

[Sialic acid containing compounds in the hemofiltrate of patients with chronic renal insufficiency. II. Isolation and structure determination of sialoglycopeptides].

Four sialyl glycopeptides have been isolated from the hemofiltrate of a patient with end stage renal disease using reverse osmosis, gel filtration and ion-exchange chromatography. Structural studies including one- and two-dimensional 1H-NMR spectroscopy, FAB mass spectrometry and enzymatic degradation indicated the following structures: (Formula: see text). While the disialyl glycopeptide has been previously characterized from normal and pregnancy urine, the three other sialyl glycopeptides could be isolated for the first time from biological material. The origin of these compounds and their possible clinical relevance is subject to further investigations.

Female↗
PubMed1987

[Isolation and NMR spectroscopic characterization of sialic acid compounds and hemofiltrate of chronic uremia patients].

Eight sialyloligosaccharides have been isolated from the hemofiltrate of a patient with end stage renal disease using reverse osmosis, gel filtration, ion-exchange and high-performance liquid chromatography. The structures were predominantly elucidated by one- and two-dimensional 1H- and 13C-NMR spectroscopy: 1 NeuAc alpha 2-3Gal beta 1-4Glc; 2 NeuAc alpha 2-6Gal beta 1-4Glc; 3 NeuAc alpha 2-3Gal beta 1-4GlcNAc; 4 NeuAc-alpha 2-6Gal beta 1-4GlcNAc; 5 NeuAc alpha 2-3Gal beta 1-4-GlcNAc alpha 1-P; 6 NeuAc alpha 2-6Gal beta 1-4GlcNAc alpha 1-P; 7 NeuAc alpha 2-3Gal beta 1-3GalNAc alpha 1-P; 8 NeuAc alpha 2-8NeuAc. While compounds 1-7 are also components of normal human urine, di-N-acetyl-D-neuraminic acid (8) could be isolated for the first time from biological material. The origin and possible clinical relevance of these compounds have to be proved in further investigations.

Blood↗
PubMed1987

[Testicular function in obstructive azoospermia].

The normal histological findings of the testicles with simultaneous azoospermia according to the former opinion renders greatly probable an obstruction of the seminal ducts. The reversed case of an ascertained obstruction, however, must not necessarily contain also normal histological structures or normal hormone tests. In the obstruction syndrome in 6 out of 23 cases we find changes in the diameter of the tubule, reductions of the spermatogenesis and changes at the interstice. Imprint-cytologically an increase of pathological spermatides at the cost of normal cell developments is shown. According to this the FSH-values are slightly but statistically significantly increased. LH, PRL and testosterone are found within the normal. For the diagnostic delimitation of the obstruction syndrome from a production azoospermia according to these findings the performance of a biopsy of the testicles with histological evaluation and the determination of the FSH-value. The relatively discrete tubular changes alone cannot be used for the explanation of the discrepancy between anatomical and functional results of the operative reconstruction of the seminal ducts.

Adult↗