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Biomedical subjects

W Hölzer

Publications and source records attributed to W Hölzer.

4 recordsLinked to original sources
PubMed1999

Serum bile acids in captive bustards.

Blood samples were collected from clinically normal male and female houbara (Chlamydotis undulata macqueenii), kori (Ardeotis kori), buff-crested (Eupodotis ruficrista gindiana) and white-bellied bustards (E. senegalensis) to determine serum bile acid concentrations. Bile acid concentrations were determined by analysis with an Ultrospec 3000 ultraviolet/visible spectrophotometer, using an enzymatic bile acid test. The results provided values of serum bile acid concentrations for the four species, with means +/- standard errors of 35.8 +/- 2.8 mumol; 51.1 +/- 5.0 mumol; 18.4 +/- 2.1 mumol and 20.8 +/- 5.4 mumol for the houbara, kori, buff-crested and white-bellied bustard, respectively. Although no gender or age differences were detected within species, the results demonstrated significant differences in concentrations in clinically normal individuals between the different species.

Animals↗
PubMed1998

Potent enzyme inhibitors derived from dromedary heavy-chain antibodies.

Evidence is provided that dromedary heavy-chain antibodies, in vivo-matured in the absence of light chains, are a unique source of inhibitory antibodies. After immunization of a dromedary with bovine erythrocyte carbonic anhydrase and porcine pancreatic alpha-amylase, it was demonstrated that a considerable amount of heavy-chain antibodies, acting as true competitive inhibitors, circulate in the bloodstream. In contrast, the conventional antibodies apparently do not interact with the enzyme's active site. Next we illustrated that peripheral blood lymphocytes are suitable for one-step cloning of the variable domain fragments in a phage-display vector. By bio-panning, several antigen-specific single-domain fragments are readily isolated for both enzymes. In addition we show that among those isolated fragments active site binders are well represented. When produced as recombinant protein in Escherichia coli, these active site binders appear to be potent enzyme inhibitors when tested in chromogenic assays. The low complexity of the antigen-binding site of these single-domain antibodies composed of only three loops could be valuable for designing smaller synthetic inhibitors.

Amino Acid Sequence↗
PubMed1993

Conformation of d(GGGATCCC)2 in crystals and in solution studied by X-ray diffraction, Raman spectroscopy and molecular modelling.

In the crystal, d(GGGATCCC)2 forms an A-DNA double helix as known from a single crystal X-ray diffraction study. Accordingly, in the Raman spectra of crystals the A-family marker bands at 664, 705, 807 and 1101 cm-1 and the spectral characteristics in the region 1200 to 1500 cm-1 clearly demonstrate the A-form as the dominant conformation. Bands at 691, 850, and 1080 cm-1, however, indicate that a minor fraction of the octamer molecules in the crystal is in an unusual, still not unequivocally identified conformation possibly belonging to the B-family. In solution, the octamer is in B-like conformation as shown by the presence of B-DNA Raman marker bands at 685, 837, 1094 and 1421 cm-1. Molecular modelling techniques lead to three structures with slightly different B-form geometries as the lowest energies models when a sigmoidal dielectric function with the bulk dielectric constant epsilon = 78 and the value q = -0.5e for the effective phosphate charges was used in the calculations. An A-form structure bearing a strong resemblance to the experimentally determined crystal structure becomes the lowest energy model structure when the electrostatic parameters are changed to epsilon = 30 and q = -0.25e, respectively.

Base Sequence↗