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Biomedical subjects

A Müller

Publications and source records attributed to A Müller.

At least 433 records · Page 24Linked to original sources
PubMed1992

Antiasthmatic effects of Galphimia glauca, gallic acid, and related compounds prevent allergen- and platelet-activating factor-induced bronchial obstruction as well as bronchial hyperreactivity in guinea pigs.

A methanolic extract from Galphimia glauca (320 mg/kg, orally) inhibited acute bronchial reactions to allergen (ovalbumin, 10 mg/ml) and platelet-activating factor (PAF, 1 microgram/ml) inhalation challenges, but not to histamine or acetylcholine in spontaneously breathing guinea pigs. Furthermore, the PAF-induced bronchial hyperreactivity was markedly reduced. Gallic acid and related compounds as well as the flavonoid, quercetin, were identified as active compounds. Gallic acid, methyl gallate and quercetin showed significant effects after a single oral dose of 45 mg/kg, tetragalloyl quinic acid after 5 mg/kg. Continuous treatment of the animals with one certain fraction (GG II, 3 days, 3 x 2 mg/kg) containing all active compounds reduced allergen- and PAF-induced bronchial reactions by more than 70%.

Animals↗
PubMed1992

[The correlation between coping with stress and blood pressure reaction].

This study explored the relationship between individual strategies of coping and blood pressure responses during and after mental stress. Blood pressure behavior was measured noninvasively and continuously before, during and after a mental stress situation in 27 normotensive subjects. Coping strategies were assessed with the Stressverarbeitungsfragebogen (SVF; coping with stress inventory). Two extreme groups were formed on the basis of the scores in the SVF. Results were: (a) Individuals who used coping strategies characterized by controlling the situation directly and constructively, in contrast to probands not using these strategies, exhibited lower blood pressure during the stress situation and a faster return to baseline levels after cessation of stress. (b) Subjects using a coping behavior characterized by the use of defense mechanisms such as suppression and denial, also showed lower blood pressure during stress but a significantly delayed return to baseline levels of blood pressure after stress was concluded.

Adaptation, Psychological↗
PubMed1992

[Effect of alcohol as a cause of fatal traffic accidents: are official figures correct?].

Starting point is the question whether in the official records of fatal road accidents driving while intoxicated is adequately taken into account as a cause. A former investigation with accident data of 1976 yielded a considerable number of undetected and not registered cases. On the basis of the fatal road accidents of the Saarland region for the years 1988, 1989 and 1990 the former results could be confirmed on the whole. Only with 25 per cent of all persons involved in a fatal accident a breath or blood test for checking alcoholic impairment had been arranged. The assumption is well substantiated that the remaining 75 per cent include many impaired persons and that not only every fifth victim of traffic accidents is a result of alcoholic impairment but about 40 per cent. Proposals are made for getting in the future more reliable counts and a better basis for fighting against DWI-offences.

Accidents, Traffic↗
PubMed1992

[Recurrences, the surgical and radiological side effects and new developments in the breast-preserving treatment of breast carcinoma].

In the Department for Gynecology and the Department for Gynecologic Radiology, University of Heidelberg, breast conserving therapy was carried out in 1,330 patients with breast cancer between 1975 and 1990. The tumor size was up to 3 cm, 28% showed positive nodes. The medium age was 47.6 years, segmental resection was the standard operation, whole breast irradiation with 50 Gy and an additional boost of 10 Gy was standard irradiation schedule. After five years (n = 307) the following results were observed: local failure 6.8%, regional lymph node recurrence 2.1%, overall survival 88.3%, disease-free survival 81.2%. Five out of 36 of the death-cases died without recurrence. Significant factors for local failure were following: 1. lymphangiosis of more than 1 cm in size around the tumor (p = 0.03); 2. intra-ductal non-invasive cancer of more than 1 cm in size around the primary (p = 0.01); 3. intra-ductal non-invasive cancer reaches the margin of resection (p less than 0.00001). With segmental resection (2 cm margin macroscopically free of tumor) showed in 19% histologically tumor beyond the margins so-called residuals. In the other three quadrants additional second primaries of (multicentric cancers) macroscopical size could be confirmed in an additional study. In case of high risk for local failure more radicality in operation as well as in irradiation is recommended.

Adult↗
PubMed1992

[Results of allogenic and autologous bone marrow transplantation in children with acute myeloid leukemia].

We report on our experience of bone marrow transplantation (BMT) in children with acute myeloblastic leukaemia (AML) and high risk of relapse (initial WBC greater than 20 x 10(9)/l, FAB M 5, M 6, M 7). 32 children were grafted between november 1982 and october 1991 at the Children's Hospital of the University of Jena. Two patients underwent an allogenous BMT in relapse and died from progressive disease. In 13 children an allogeneic BMT was performed in first complete remission. One patient relapsed, two patients died from severe acute graft-versus-host disease, and two patients died from encephalopathy and cardiomyopathy. Eight of the 13 patients are living and well 18 months to eight and a half year after BMT. Seventeen patients received an autologous (unpurged) BMT. Four of them relapsed four to seven months after BMT. The disease free survival (DFS) for the 29 patients grafted in remission was 0.65. There was no statistical significant difference in DFS between patients with allogeneic and autologous BMT. We conclude that in children with AML and high risk for relapse BMT offers a real chance for better survival. Autologous BMT avoids the problems of graft-versus-host disease and of finding suitable donors for allogeneic marrow transplantation.

Adolescent↗
PubMed1991

Chloroplast Rieske Center. EPR study on its spectral characteristics, relaxation and orientation properties.

The spectral parameters, the orientation of the g tensor in two-dimensionally ordered multilayers and the relaxation properties of the Rieske center in purified cytochrome b6f complex from spinach were studied by EPR spectroscopy. A trough at g = 1.76 - 1.74 was unambiguously identified as the gx signal on the basis of the sensitivity of its field position to inhibitors and oxidized plastoquinone. In contrast to previous reports, the orientation of the chloroplast Rieske center was found to be identical to that of its cytochrome bc1 counterpart, provided that non-saturating EPR conditions were applied. Upon onset of microwave saturation, however, the orientation with respect to the ordered multilayers where the gy signal (g = 1.9) was maximal, changed drastically and was then similar to the orientation reported previously (Prince R. C., Crowder, M. S., and Bearden, A. J. (1980) Biochim. Biophys. Acta 592, 323-337). The unusually anisotropic saturation behavior of the EPR spectrum was characterized in detail, whereby hitherto controversial results on the spectral parameters of the chloroplast Rieske center could be rationalized. The observed phenomena are discussed on the basis of three tentative models which are able to qualitatively explain the effects.

Chloroplasts↗
PubMed1991

Inhibition of proteinase K by methoxysuccinyl-Ala-Ala-Pro-Ala-chloromethyl ketone. An x-ray study at 2.2-A resolution.

The crystal structure of the transition state analog complex formed covalently between proteinase K and methoxysuccinyl-Ala-Ala-Pro-Ala-chloromethyl ketone was determined by x-ray diffraction methods at a resolution of 2.2 A and refined by constrained least squares to an R factor of 19.8% for the 11864 structure amplitudes greater than 1 sigma F. The chloromethyl ketone group is covalently linked with the active site functional groups His69(N epsilon) and Ser224(O gamma). The former has substituted for chlorine and the latter has attacked the carbon of the ketone group, thereby forming the tetrahedral carbon atom of the transition state analog. The peptide part of the inhibitor is in an extended conformation and fills subsites S1 to S5 of the substrate recognition site. Its backbone hydrogens bond with strands 100-104 and 132-136 of the substrate recognition site as the central strand of a three-stranded antiparallel beta-pleated sheet. This sheet formation is associated with a movement by approximately 1 A of strand 100-104 which is probably associated with the insertion of the bulky proline side chain. The methoxysuccinyl group is stacked on the phenolic side chain of Tyr104 that is a part of the bottom of the recognition site. Biochemical studies show that shorter inhibitors of this type are less effective than the longer one, because there are fewer hydrogen bonding and van der Waals/stacking interactions.

Amino Acid Chloromethyl Ketones↗
PubMed1991

[Long-term therapy of Ménétrier disease using ranitidine and pirenzepine].

A 22-year-old woman with hypertrophic protein-losing gastropathy (Ménétrier's disease) is described. During treatment with ranitidine (Zantic) and pirenzepine (Gastrozepin) the gastric mucosa and protein loss were normalized within 4 years. Clinical and histological remission has now been observed for 5 and 3 years respectively. In a 57-year-old woman with hypertrophic gastropathy, 8 months' treatment with ranitidine and pirenzepine was associated with decrease in protein loss and improvement of the histological appearance of the gastric mucosa after one year. Long-term treatment of hypertrophic gastropathy with ranitidine and/or pirenzepine should, therefore, be considered in such cases instead of gastrectomy.

Adult↗
PubMed1991

Selective removal of molybdenum traces from growth media of N2-fixing bacteria.

A new method for the selective removal of traces of molybdenum from growth media of N2-fixing bacteria (Rhodobacter capsulatus and Klebsiella pneumoniae) was developed. This method is based on the filtration of nutrient solutions through a layer of activated carbon (pulverized charcoal). The adsorption of Mo (molybdate) to activated carbon was optimal if a charcoal suspension (50 g/liter) was degassed by boiling before use and if the pH of the solutions, which had to be purified, was adjusted to values between 1.5 and 4. In this pH region no or only negligible amounts of other metal ions were adsorbed. The activated carbon method was compared with other Mo-eliminating procedures, including 8-hydroxyquinoline/dichloromethane extraction, Chelex 100 chromatography, and treatment with Mo-starved Azotobacter vinelandii cells. The activated carbon filtration appeared to be the most effective, specific, and rapid method. Whereas the untreated Rhodobacter growth medium was contaminated with 1.2 ppb Mo, as analyzed by inductively coupled plasma mass spectrometry (ICP-MS), the activated carbon-treated medium was below the ICP-MS detection limit (less than 0.05 ppb). A similarly effective removal of Mo impurities was obtained by the Azotobacter treatment. Even at low optical densities (2-5 at 436 nm) Mo traces were removed very rapidly within 10-15 min. However, because the Mo uptake/Mo adsorption capacity of A. vinelandii depended on freshly cultivated cells and on the growth phase at which the cells were harvested, this microbiological method was generally more time-consuming and less reproducible than the activated carbon method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMed1991

Collagen peptidase and type III procollagen peptide serum levels in chronic liver diseases.

The concentration of the N-terminal peptide of procollagen III and the activity of collagen peptidase (PZ-peptidase) were measured in sera from 92 patients with chronic liver disease. In patients with liver cirrhosis and chronic hepatitis with transformation of liver structure, high values were found for both variables compared with hepatoses and chronic hepatitis without transformation. The concentration of procollagen III peptide and the activity of collagen peptidase in serum increased with increasing degrees of fibrosis and, even more markedly, with increasing degrees of mesenchymal activity in the liver.

Adult↗
PubMed1991

Demonstration of a molybdenum- and vanadium-independent nitrogenase in a nifHDK-deletion mutant of Rhodobacter capsulatus.

In Rhodobacter capsulatus there exists, in addition to a conventional Mo-containing nitrogenase, a second, Mo-indendent nitrogenase which was demonstrated in wild-type cells as well as in cells of a nifHDK- mutant. To construct this R. capsulatus mutant, a 4-kb BglII-HindIII fragment encompassing nifK, nifD and most of the nifH coding region was substituted by an interposon coding for kanamycin resistance. The alternative nitrogenase is repressed by molybdenum. Mo concentration greater than 1 ppb in the growth medium prevented diazotrophic growth of nifHDK- cells and the expression of nitrogenase activity. The Mo-independent nitrogenase was maximally derepressed in activated carbon-treated media which contained less than 0.05 ppb Mo, high concentrations of iron (1 mM ferric citrate) and serine as N source. Under N2-fixing and optimal Mo-deficient conditions, nifHDK- cells grew with a doubling time of 9 h. The highest activity achieved with whole cells was 1.2 nmol ethylene.min-1.mg protein-1. Vanadium neither stimulated nor inhibited growth and activity. The alternative nitrogenase reduced acetylene to both ethylene and ethane. With whole cells (nifHDK-) the proportion of ethane varied over 2-5% depending on the amount of residual traces of Mo in the medium. The addition of Mo to a growing, nitrogenase-active culture resulted in a slow decrease of total activity but also in a simultaneous increase of ethane production up to 40%. In contrast, cell-free extracts and the purified enzyme did not show any or only very little ethane formation (0-0.4%). Both enzyme components appeared to be very labile proteins. Component 2 lost almost all its activity during cell breakage. With component 1 in crude extracts, if complemented with the stable component 2 of the Mo-nitrogenase from Xanthobacter autotrophicus, a recovery of 50% of the original whole cell activity could be achieved. During purification, component 1 (from the nifHDK- mutant) remained remarkably stable. The partially purified component 1 had a pH optimum (acetylene reduction) of 7.8-8.0, relatively high affinity to acetylene (Km = 0.055 mM) and was analyzed to contain 20 mol Fe atoms/mol protein, 0.2 mol Mo atoms and negligible amounts of V, W and Re. The dithionite-reduced dinitrogenase appeared to be ESR-silent. The results indicate that the alternative nitrogenase of R. capsulatus is not a vanadium enzyme but rather a heterometal-free Fe-nitrogenase or a nitrogenase with an as-yet-unidentified heterometal atom.

Chromatography, Gel↗
PubMed1991

Studies on psoriatic osteopathy.

To demonstrate an as yet merely postulated generalized osteopathy in psoriatics, the serum calcium level, the alkaline phosphatase in the serum and the urinary excretion of hydroxyproline were evaluated in 24 patients with Ps and 24 patients with PA. Moreover, the bone bioptates from 25 patients with PA and 10 patients with Ps were examined histologically and measured morphometrically. The investigations provide evidence for the existence of a generalized "latent" osteopathy in terms of an elevated bone turnover rate without loss of bone volume (high turnover remodelling) in both patients with PA as well as those with Ps without arthritis. As a pathogenetically essential factor shared by dermatosis and "osteopathy", latent vitamin D deficiency and/or D hormone resistance is discussed.

Adult↗
PubMed1991

Model experiments for immunomagnetic elimination of leukemic cells from human bone marrow. Presentation of a novel magnetic separation system.

Optimal conditions for removing leukemic cells from human bone marrow with monoclonal antibodies (mAb) and magnetic immunobeads were investigated. Monodisperse 3 microns polystyrene microspheres containing magnetite were coated with affinity-purified rabbit antimouse IgG at 4 degrees C, pH 9.6 for 18 h. SKW-3 cells (T-CLL cell line) were marked with the supravital DNA stain Hoechst 33342, seeded into normal human bone marrow, and then incubated with the mAb CD1, CD6, and CD8 at 4 degrees C for 30 min. In preliminary experiments REH cells (cALL cells) and mouse anti-REH cell antibodies were used to find the most favorable conditions for the binding of magnetic beads to tumor cells. Optimal formation of cell-bead rosettes was achieved by rotating beads and tumor cells together at room temperature at a concentration of 1 x 10(7) cells/ml, a bead: tumor cell ratio of 100:1 and an incubation time of one hour. The novel magnetic separation apparatus consists of three polystyrene chambers connected by silicone rubber tubing. The chambers contain four steel inserts each equipped with 32 nickel wires, which are magnetized by permanent magnets in such a way that the inhomogeneous high gradient magnetic field could be established within the cell suspension containing the cells to be depleted. The fluid flow was established by a peristaltic pump. At a flow rate of 1.5 ml/min and a field strength of 160 kA/m, no beads could be detected in the purged marrow. A cocktail of the three mAb was more effective than any single antibody in forming bead-cell rosettes. Two sequential purging cycles were superior to one. The marrow recovered was highly viable as assessed by trypan blue dye exclusion and by growth of CFU-GM.

Antibodies, Monoclonal↗