Biomedical subjects

W H Hopff

Publications and source records attributed to W H Hopff.

11 recordsLinked to original sources

PubMed1992

Interaction of obidoxime with sarin in aqueous solution.

The interaction of obidoxime (Toxogonin) with sarin was shown by different analytical methods. The UV spectrum of obidoxime at pH 7.4 yields two absorption maxima, lambda 1 = 284 nm and lambda 2 = 353 nm. The peak at lambda 2 = 353 nm is representative for the amount of zwitter-ionic obidoxime, i.e. the active form of obidoxime. By addition of sarin, lambda 1 shifts immediately to 278 nm and the intensity at lambda 2 decreases, thus indicating an interaction. TLC and 31P-NMR evidence shows that both mono-phosphonylated and diphosphonylated obidoximes are present. Decomposition of phosphonylated obidoxime in MOPS (3-[N-morpholino] propanesulfonic acid) buffered D2O at pH 7.4 occurs with t1/2 = 13.3 min at 24 degrees C. Decomposition of di-phosphonylated obidoxime is faster. It is suggested that decomposition of di-phosphonylated obidoxime occurs through the mono-phosphonylated form. Formation and decomposition of mono- and di-phosphonylated obidoxime is pH dependent. We conclude that obidoxime exerts a detoxifying effect by capturing free sarin molecules and thus increasing its polarity. Thereby the transition of sarin through the blood-brain barrier is restricted and its renal elimination facilitated.

Chromatography, Thin Layer↗

PubMed1990

[Homeopathy].

Homeopathy has been disputed from the early beginning. The rational basis of homeopathy neither can be established by philosophy nor by natural sciences. On one hand homeopathy is supported by so-called 'empirical physicians', but on the other hand it is usually heavily criticized by physicians who are basing their criticism on natural sciences. 'Healing' is meant to prove the hypothesis of all paramedical people, it can however be easily explained on a rational basis. It is indisputable that paramedical manipulations not only may act by placebo effect but also can appear successful due to the remarkable power of our body for self-healing. If latter plays an important role, especially when there is no time limit for healing. We never tried to convince paramedical ideologists, who are already heavily engaged in paramedical treatment, but it is our aim to reassure with solid arguments colleagues, who have so far been overwhelmed by irrational journalism.

Europe↗

PubMed1989

Isolation and purification of acetylcholine receptor proteins by affinity chromatography.

In order to further molecular investigations on the binding capacity of acetylcholine receptors, a method was developed for the affinity chromatography of the nicotinic acetylcholine receptor. Reversibly binding cholinergic ligand groups were used as affinity ligands, instead of the well known snake venom alpha-toxins. These ligands are small in size, chemically well defined and fixed to long spacer chains (at least 40 nm). One ligand, with a pharmacologically stabilizing effect on the receptor, was a derivative of gallamine. Another, with a depolarizing effect, resembled carbamoylcholine and a third was a derivative of decamethonium. The receptor proteins were isolated from Torpedo marmorata electric organs. Preparation included solubilization with a non-ionic detergent, alkaline treatment to extract peripheral membrane proteins and affinity purification. The receptor proteins eluted from the three affinity resins were identical in their assembly of subunits (alpha, beta, gamma and delta) but of different purity. Receptor proteins were obtained on a large scale within a short time and under mild conditions for elution with the affinity ligands of the decamethonium or the gallamine type. This was a considerable advantage compared to the use of alpha-bungarotoxin.

Animals↗

PubMed1987

[Neomysticism in medicine. The example of homeopathy].

The revival of neomysticism, especially promoted by nonqualified representatives of press and tv, leads to a worldwide trend to homoeopathy, acupuncture, herb-cure, Christian-Science, and to many others. According to the comprehensive publications of Prokop, the successful treatment by paramedical methods are due to placebo and self-healing. The statements of paramedical representatives will be accepted by the public, if representatives of science do not offer adequate criticism. Successful healing by any kind of treatment--e.g. of disturbances of well-being--is well established. Representatives of paramedicine applying "mystical treatment" to humans are obliged with necessity to explain success as "mysticism". In any case it is unwise to use the basis of natural science to explain mystic phenomena, as the representative of paramedicine--and occasionally a "mystic-oriented" representative of natural science--proves his lack of sound judgement.

Homeopathy↗

PubMed1987