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Biomedical subjects

B Völker

Publications and source records attributed to B Völker.

At least 19 recordsLinked to original sources
PubMed1992

Mast cell frequency in soft tissue tumors. Relation to type and grade of malignancy.

A high content of mast cells (MC) is considered characteristic of neurofibromas but not of malignant schwannomas and neurilemmomas. We examined the extent and reliability of this finding by counting MC in 61 peripheral nerve sheath tumors and in 103 non-neurogenic soft tissue sarcomas. We furthermore investigated correlations between the amount of MC and various features of the tumors (e.g. grades of malignancy). Neurofibromas had very high mast cell counts. However, this result only applied to about 70% of these tumors. Malignant schwannomas, malignant fibrous histiocytomas and leiomyosarcomas had remarkably high median values of MC counts with a wide dispersion within the histological groups. Synovial sarcomas were the only group that contained MC in every case, though often in small numbers. In univariate analyses the number of MC was negatively correlated to grades of malignancy, cellularity and mitotic activity of the sarcomas and tended to correlate positively to the amount of myxoid and collagenous connective tissue and lymphocytic infiltrates. Multiple linear regression analysis revealed a significant correlation to the grade of malignancy and the amount of connective tissue.

Cell Count↗
PubMed1991

[Zygomycoses: clinical aspects and pathology in 10 patients].

Deep fungal infections caused by zygomycetes (so-called mucormycoses) are rare. Whereas in the past rhinocerebral mycosis dominated, today a wide range of clinical manifestations must be expected, especially pulmonary infections and invasion of vessel walls with systemic infarction. On the basis of 10 cases of Mucoraceae mycosis and a review of the literature, the predisposing conditions, clinical symptoms and pathologic-anatomic findings are described. Our observations include 7 patients with leukemia and 2 adults and one newborn without malignant neoplasia. Except for the patient with rhinocerebral mycosis, the diagnosis was not established during the patients' lifetime. 3 patients received systemic antimycotic therapy. Our observations suggest that infarctions of internal organs in immunocompromised patients should direct suspicion towards angio-related mycoses, not only of aspergillosis, but also of zygomycosis.

Adult↗
PubMed1989

Kinetic analysis and simulation of glucose transport in plasma membrane vesicles of glucose-repressed and derepressed Saccharomyces cerevisiae cells.

In this study experimental data on the kinetic parameters investigated by other authors 1-5, 11 together with own data on plasma membrane vesicles, have been subjected to a computer simulation based on the equations describing facilitated diffusion. The simulation led to an ideal fit describing the above data. From this it can be concluded that glucose is transported by facilitated diffusion, and not by active transport as was postulated by Van Steveninck 14,15. The simulation method also demonstrates that the fast sampling technique used by these authors 1-5, 11 underestimated the fluxes. Thus, the parameters given do not contribute to the understand of glucose transport under different metabolic conditions. The K value of plasma membrane vesicles prepared from glucose-repressed cells is around 7 mM. Derepression, particularly by galactose, causes a highly significant increase in affinity as shown by a decrease in the K value to 2 mM. The highest affinity was measured in a triple kinaseless mutant grown on glycerol with a K value of 1 mM. It seems, therefore, that the kinetic parameters derived from initial uptake rates of glucose in intact cells 1-5, 11 using single flux analysis, such as Eadie-Hofstee- or Lineweaver-Burk-plots, are in error.

Biological Transport↗
PubMed1989

Lyme-borreliosis and possible association with HLA-antigens.

The frequencies of HLA A, B, C and DR antigens were evaluated in 220 persons from West Germany with inapparent and manifest Borrelia burgdorferi infections. Thirty-seven forest workers showing elevated antibody titres against Borrelia burgdorferi had asymptomatic infection, and are described as stage 0. One hundred and eighty-three patients presented with the clinical stages 1-3 of the infection. Control persons (n = 655) were typed in the same time period and by identical staff. HLA CW3 was present in 36.3% of patients as compared to 23.2% of the controls (RR = 1.88, pcorr = 0.03) and was significantly associated with manifest infection. In addition, the antigen A2 was found slightly but not significantly more frequent in the patients (55.2% vs 44%; pcorr = 0.41). The phenotype combination HLA A2 and Cw3, however, was significantly elevated in patients (24.6% vs 10.8%; pcorr = 0.0005). In contrast to these class 1 antigens, HLA DR3 showed a tendency of negative association with manifest infection. But this finding was not yet found to be significant (15.3% vs 25.3%; RR = 0.53, pcorr = 0.26). The frequency of HLA DR2 showed a constant decrease from stage 0 to stage 3 (inapparent infection to late complications). Using the rank correlation coefficient of Spearman, this association was found to be significant (-1.00, p less than or equal to 0.05). All other tested HLA antigens and antigen combinations showed no significant differences. The data suggest that HLA CW3 may be associated with Borrelia burgdorferi infection, whereas HLA DR2 and DR3 may be associated with less incidence of severe courses and less complications in this disorder.

Borrelia Infections↗
PubMed1987

[Glaucoma].

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Glaucoma↗
PubMed1987

[Strabismus].

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Humans↗
PubMed1986

A comparison of the influence of temporary balloon buckles and permanent episcleral silicone sponges on postoperative ocular motility in retinal detachment surgery.

The influence of retinal surgery on ocular motility was examined in 60 patients with rhegmatogenous retinal detachment caused by one tear. Thirty patients were treated with cryotherapy and an episcleral radial silicone sponge explant. The remaining 30 patients were treated with a Lincoff temporary balloon buckle procedure. Extensive pre- and postoperative orthoptic examinations showed the impairment of ocular motility to be significantly less with the balloon-buckle procedure.

Eye↗
PubMed1985

[Intraocular penetration of systemically administered cephalosporins under steady-state conditions in animal experiments].

In previous studies of intraocular penetration of systemically applied antibiotics a single dose of the antibiotic was applied. An experimental study was performed in order to determine if maintaining a constant serum level for an extended period of time will lead to an increase in ocular concentration. The antibiotic dosage was calculated so that the serum level remained constant for a given period of time. Using the rabbit as an experimental animal two cephalosporins (Cefsulodin, Cefotiam) were then injected intravenously using an infusion pump. Evaluation of serum levels (high-performance liquid chromatography) revealed constant levels for each animal but different interindividual levels. The intraocular concentrations of Cefsulodin and Cefotiam were different. The intraocular level of Cefsulodin rose continuously over a period of 5 h, whereas the Cefotiam levels remained at the concentration measured after bolus injection.

Animals↗
PubMed1977

[Electroencephalographic examinations in emotionally disturbed children and adolescents (author's transl)].

Electroencephalographic examinations were conducted on 250 emotionally disturbed children and adolescents (175 boys and 75 girls) between the ages of 6 and 18. ll8 (47.2%) of the children and adolescents had an EEG which corresponded with their age group. 88 (35.2%) of the patients showed a HV alteration without any pathological graphologic elements. The electroencephalography in 44 cases (17.6%) clearly showed abnormal and/or pathological alterations. Frequently conspicuous findings were present in children with aggressive behavior, learning problems, anxiety syndromes as well as enuresis and encopresis. The alterations were less pronounced in those children who stuttered and the obsessive neurotics. No statistical significance, however, could be established. A correlation could not be established between a particular psychological symptom and a specific EEG alteration. Our results correspond in this regard with those presented in the literature. The majority of the authors, however, recorded conspicuous EEG findings much more frequently than we did. Basically, an electroencephalographic examination for emotionally disturbed children seems to be necessary for the recognition of somatic factors. For the evaluation, however, the range of variation of the normal encephalogram in children and its special characteristics at various age levels should be taken into consideration.

Adolescent↗