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Biomedical subjects

G Müller

Publications and source records attributed to G Müller.

At least 217 records · Page 12Linked to original sources
PubMed1997

[Experimental affecting of pulmonary clearance of Pasteurella multocida induced pneumonia in swine].

The pulmonary clearance of Pasteurella multocida in weaner pigs was not affected by Carrageenan and Silica, two substances which block the function of monocytes/macrophages. Neutropenia, caused by the application of hydroxyurea, however, inhibit the pulmonary clearance markedly and reduced the severity of simultaneously induced pneumonias considerably. This indicates the importance of polymorphonuclear neutrophils for early clearance mechanisms and their inflammation inducing and maintaining effects.

Animals↗
PubMed1997

[In vitro evaluation of blood vessel prosthesis dilatation--Dacron and PTFE--a new measuring technique].

Dilatation is the most significant complication of prosthetic vascular grafts. It is suspected to be a nidus of other graft complications. There have been a few studies on in-vitro-dilatation of the prosthetic vascular grafts. This is due to the lack of an effective and simple method to measure the transverse dilatation of the graft. We developed a new simple, reliable and cost-effective technique to evaluate the in-vitro-dilatation of prosthetic vascular grafts. The dilatation behavior of two different types of grafts (dacron and PTFE) was observed and compared under static pressure between 0 and 300 mmHg. The in-vitro- dilatations of dacron and PTFE grafts were 6.9% and 8.4% respectively. Interestingly, the dilatation rate for PTFE vascular grafts is higher than the indicated rate in the literature.

Blood Vessel Prosthesis↗
PubMed1997

Ion beam slope cutting in dentistry: a catalog of applications.

It is very difficult to prepare structures of heterogeneous materials, material interfaces, or sensitive biologic samples. The usual grinding, cutting, or fracturing methods are mostly material destructive because of resulting shear strengths. Ion beam slope cutting allows microcuts to be accurately placed into subsurface areas. The material reduction is based on the principles of ion sputtering, whereby atoms are removed in the area of ion incidence. The speed of removal depends on the sputtered material, amounting to several micrometers per hour. Approximately 40 biologic dental specimens of various origin were examined. Depending on the incidence angle of the ion beam, the typical structures of ion etching can be reduced or intensified. Both variants are used to obtain a precise judgment of morphologic details or an exact topography of failures.

Dental Materials↗
PubMed1997

[Vacuum dressing in septic wound treatment].

During the last 2 years, we used the vacuum-sealing technique in more than 300 patients. We have seen several advantages: clean and sterile wound dressing and safe wound healing. In addition, we have used the technique successfully in infected areas in combination with alloplastic material. The only problem we found is the dependency on operating theatres and a vacuum. We think the technique should be recommended for septic wounds in surgery.

Combined Modality Therapy↗
PubMed1997

[Pelvic exenteration--indications, radical nature and follow-up demonstrated with 33 clinical cases].

From March 1983 to March 1997, 24 posterior pelvic exenterations and 9 total pelvic exenterations were performed in 18 patients with recurrent cancer and 15 patients with primary cancer. In 85%, we saw major complications, 78% in primary operations and significantly higher--96%--in recurrent cancer operations. R0 resections we figured out in 67% of primary operations and 40% of recurrent operations. We saw recurrent cancer in 45% of the patients with a mean follow-up of 18.2 months.

Adult↗
PubMed1996

Biosynthesis of vitamin B12: factor IV, a new intermediate in the anaerobic pathway.

The structure of a novel tetradehydrocorrin, factor IV, isolated from Propionibacterium shermanii has been established by multidimensional NMR spectroscopy. Incorporation of radiolabeled factor IV into cobyrinic acid established the biointermediacy of this cobalt complex, whose structure has implications for the mechanisms of the anaerobic pathway to B12.

Anaerobiosis↗
PubMed1996

Impact of concentrations of glycated hemoglobin, alpha-tocopherol, copper, and manganese on oxidation of low-density lipoproteins in patients with type I diabetes, type II diabetes and control subjects.

The late organ complications in diabetic patients are associated with enhanced oxidation of low-density lipoproteins (LDL). The role of vitamin and trace metal concentrations in this process is not clear. Therefore, we compared the oxidative susceptibility and alpha-tocopherol concentration of LDL with the levels of glycated hemoglobin (HbA1c), copper and manganese. Sixty-three diabetic patients (23 female and 40 male; 53 of type II, 10 of type I) and 35 control subjects (17 female and 18 male) were investigated. The in vitro-formation of conjugated dienes in purified LDL preparations in the presence of copper was followed as absorbance at 234 nm. LDL exhibited a shorter lagtime (44.5 +/- 10.1 vs. 67.8 +/- 16.0 and 50.1 +/- 14.3 vs. 68.8 +/- 14.6 min) for type I and type II diabetic patients vs. sex and age-matched controls, P < 0.001. For all subjects together the lagtime was inversely correlated to HbA1c (r = -0.230, P = 0.023) and positively correlated to LDL alpha-tocopherol/LDL (mol/mol). This ratio was lower in diabetic patients (P < 0.01 for type II) than in control subjects. The copper and manganese plasma levels were not different between diabetic and nondiabetic groups. However, parameters of LDL oxidizability (amount and rate of oxidation) were positively correlated with both copper and manganese concentrations. We conclude that in diabetes the resistance of LDL against oxidation is diminished in relation to the quality of glucose control.

Adult↗
PubMed1996

Interstitial deletion 5p accompanied by dicentric ring formation of the deleted segment resulting in trisomy 5p13-cen.

Karyotypes with an interstitial deletion and a marker chromosome formed from the deleted segment are rare. We identified such a rearrangement in a newborn infant, who presented with macrocephaly, asymmetric square skull, minor facial anomalies, omphalocele, inguinal hernias, hypospadias, and club feet. The karyotype 46,XY,del(5) (pter --> p13::cen --> qter)/47,XY,+dicr(5)(:p13 --> cen::p13 --> cen), del(5)(pter --> p13::cen --> qter) was identified by banding studies and FISH analysis in the peripheral lymphocytes. One breakpoint on the del(5) maps distal to GDNF, and FISH analysis using an alpha-satellite probe suggests that the proximal breakpoint maps within the centromere. The dicentric r(5) consists of two copies of the segment deleted in the del(5), resulting in trisomy of proximal 5p (5p13-cen). The phenotype of the propositus is compared with other trisomy 5p cases and possible mechanisms for the generation of this unique chromosomal rearrangement are discussed.

Abnormalities, Multiple↗
PubMed1996

Fast large-scale purification of tetracycline repressor variants from overproducing Escherichia coli strains.

We constructed a plasmid for overexpression of Tn10 Tet repressor (TetR) by placing a synthetic tetR gene under control of the Pc promoter. Active TetR is expressed up to 30% of the total soluble cell protein. A protocol containing anion-exchange, cation-exchange, and size-exclusion chromatography steps is described for the large-scale purification of milligram amounts of TetR in three days. Cation-exchange chromatography already yields almost homogenous TetR. Purification of about fifty TetR mutants demonstrates that this protocol is generally applicable. No correlation between net charge of TetR variants and elution behaviour was detected for the anion-exchange column. On the other hand, TetR mutants with increased negative charge in their DNA binding domain eluted at lower NaCl concentration from the cation-exchange column. The applicability of this purification protocol to the wide variety of TetR variants suggests that it can be used for the rapid purification of other DNA binding proteins as well.

Alleles↗
PubMed1996

In vitro studies and computer simulations to assess the use of a diode laser (850 nm) for laser-induced thermotherapy (LITT).

BACKGROUND AND OBJECTIVE: This study investigated the feasibility of 850 nm diode laser-induced thermotherapy (LITT), a new procedure providing local hyperthermia and photocoagulation, a minimally invasive treatment of tumors, and other disorders such as benign prostate hyperplasia. STUDY DESIGN/MATERIAL AND METHODS: An improved fiber optic diffuser inserted through a catheter was used to irradiate prostate, liver, and kidney tissue in-vitro. Experimental results were compared with predictions from mathematical simulations based on measured optical tissue parameters. RESULTS: After 10 minutes of irradiation with 2-4.6 W CW laser power, sizable coagulation diameters had been achieved. In prostate and kidney tissue, temperature rises and coagulation diameters after laser irradiation were found to be smaller than in liver tissue. Those tissues also had a higher threshold for carbonization, thus reducing the risk of damage to the delivery system. CONCLUSION: The data suggest that a low power diode laser can be recommended for use in LITT to treat prostate and kidney tissue.

Animals↗
PubMed1996

Specific stabilization of the 4F7 molecule on dendritic cells by contact allergens.

Our laboratory has recently developed the monoclonal antibody 4F7 which recognizes a molecule on dendritic cells in the dermis of mice that is upregulated after application of contact allergens in vivo. Furthermore, this antibody detects an antigen on dendritic cells in spleen, lymph nodes and colon. In order to study the influence of contact allergens on the surface expression of the 4F7 molecules on dendritic cells, FACScan analysis of splenic dendritic cells was carried out after in vitro application of contact allergens. Freshly isolated splenic dendritic cells were found to be positive for 4F7, 33D1, N418 (CD11c) and MHC class II. After overnight culture the expression of the dendritic cell-specific molecules 4F7 and 33D1 was decreased. This downregulation was not inhibited by the addition of the cytokines TNF-alpha or GM-CSF during in vitro culture. However, in vitro treatment of freshly isolated dendritic cells with the contact allergen 2,4-dinitrofluorobenzene prevented this downregulation of the 4F7 surface molecules. The same effect was observed after treatment with other contact allergens (1-chloro-2,4-dinitrobenzene or potassium dichromate). Treatment with the irritant substance sodium dodecyl sulphate, the lectins concanavalin and lipopolysaccharide or the phorbol ester PMA did not prevent the downregulation of 4F7 and 33D1. Moreover, the influence of contact allergens on the expression of the molecules 4F7 and 33D1 was not inhibited by the protein synthesis inhibitor cycloheximide. No effects of contact sensitizers were detectable on the expression of MHC class II molecules or the costimulatory molecules B7 and heat-stable antigen. Our results show a specific stabilizing effect of contact allergens on the dendritic cell-specific molecules 4F7 and 33D1 independent of de novo protein synthesis.

Allergens↗
PubMed1996

A multiwell plate procedure for immunohistochemical and histochemical staining of constituents of articular cartilage.

A multiwell plate procedure was tested for its applicability to determine immunohistochemically the noncollagenous matrix protein COMP (cartilage oligomeric matrix protein) and histochemically the proteoglycans of the matrix of articular cartilage. Fixed and decalcified cartilage-bone sections were treated with buffer, antisera, substrate or staining solutions in the wells of an assay plate under shaking on a rocking table. This floating procedure results in a reproducible histochemical or immunohistochemical staining and might therefore be valuable to determine or to detect other constituents of the matrix of these connective tissues under comparable conditions.

Animals↗
PubMed1996

Characterization of the molecular mode of action of the sulfonylurea, glimepiride, at beta-cells.

Glimepiride was compared with glibenclamide for its insulin secretion stimulating and beta-cell membrane depolarizing activity as well as for its binding kinetics to beta-cell membranes and for its beta-cell membrane binding proteins. Steady state, kinetic and competitive binding studies revealed a 3- to 4-fold lower binding affinity of glimepiride to isolated beta-cell membranes and intact beta-cells compared to glibenclamide. Direct photoaffinity labeling of beta-cell membrane proteins with the radiolabeled sulfonylureas identified a 65-kDa binding protein for glimepiride and a 140-kDa binding protein for glibenclamide which may be the basis for the different binding characteristics of the two sulfonylureas. The inhibition of binding and photoaffinity labeling of glimepiride and glibenclamide to the 65- and 140-kDa protein, respectively, by glibenclamide and glimepiride can be explained with allosteric interactions between two distinct sulfonylurea binding proteins, subunits of a KATP protein complex, each regulating the open/closed-state of a common separate pore-forming subunit by allosteric interactions. Whole-cell patch clamp experiments with RINm5F cells demonstrated a 3- to 4-fold lower depolarization activity of glimepiride compared to glibenclamide which correlates well with the lower binding affinity of glimepiride. The lower binding affinity and depolarization activity of glimepiride were not reflected in vitro in perifused islets and the isolated perfused pancreas of the rat. This discrepancy remains to be elucidated. The binding, depolarisation and insulin releasing characteristics of glimepiride and glibenclamide suggest that different sulfonylureas can interact with different components of KATP.

ATP-Binding Cassette Transporters↗