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Biomedical subjects

F Erdmann

Publications and source records attributed to F Erdmann.

12 recordsLinked to original sources
PubMed2001

Multiple homicides as a result of chloroform poisoning: case report and experimental study.

Two cases (involving five murder victims) of multiple homicide by inhalational chloroform intoxication are reported. In the discussion of the findings the valence of toxicological analyses is underlined with regard to the possibility of forcible external suffocation due to occlusion of the respiratory orifices by means of a chloroform-soaked soft covering. In addition storage experiments were performed at +4, +20 and -20 degrees C with cadaver blood mixed with chloroform. The optimal solution for avoiding volatile losses was stored in glass tubes with ground glass stoppers. In cases of unclear death in which involvement of volatile substances is suspected it is, therefore, advisable to preserve an additional blood sample at -20 degrees C in glass tubes that are only opened for the analysis of volatile substances.

Adolescent↗
PubMed2001

Reversible inhibition of calcineurin by the polyphenolic aldehyde gossypol.

The reversible inhibition of calcineurin (CaN), which is the only Ca(2+)/calmodulin-dependent protein Ser/Thr phosphatase, is thought to be a key functional event for most cyclosporin A (CsA)- and tacrolimus (FK506)-mediated biological effects. In addition to CaN inhibition, however, CsA and FK506 have multiple biochemical effects because of their action in a gain-of-function model that requires prior binding to immunophilic proteins. We screened a small molecule library for direct inhibitors of CaN using CaN-mediated dephosphorylation of (33)P-labeled 19-residue phosphopeptide substrate (RII phosphopeptide) as an assay and found the polyphenolic aldehyde gossypol to be a novel CaN inhibitor. Unlike CsA and FK506, gossypol does not require a matchmaker protein for reversible CaN inhibition with an IC(50) value of 15 microm. Gossypolone, a gossypol analog, showed improved inhibition of both RII phosphopeptide and p-nitrophenyl phosphate dephosphorylation with an IC(50) of 9 and 6 microm, respectively. In contrast, apogossypol hexaacetate was inactive. Gossypol acts noncompetitively, interfering with the binding site for the cyclophilin 18.CsA complex in CaN. In contrast to CsA and FK506, gossypol does not inactivate the peptidyl-prolyl-cis/trans-isomerase activity of immunophilins. Similar to CsA and FK506, T cell receptor signaling induced by phorbol 12-myristate 13-acetate/ionomycin is inhibited by gossypol in a dose-dependent manner, demonstrated by the inhibition of nuclear factor of activated T cell (NFAT) c1 translocation from the cytosol into the nucleus and suppression of NFAT-luciferase reporter gene activity.

Amino Acid Sequence↗
PubMed1998

Different utilization of neutral lipids by Malassezia furfur and Malassezia sympodialis.

In recent years, the genus Malassezia has been expanded based on molecular data; in addition to M. furfur and M. pachydermatis, five new species (M. sympodialis, M. globosa, M. obtusa, M. restricta, M. slooffiae) have been described. Apart from their lipid dependence, little is known about the metabolism and nutritional requirements of these new species. Defined inocula of Malassezia reference strains were cultured on selective agar for pathogenic fungi which was overlaid with olive oil. Samples of the olive oil overlay were taken at regular intervals and the lipid fractions were analysed by high performance thin layer chromatography. Depending on the time of incubation and the number of cells, M. sympodialis and the other recently described species produced a significant increase in free fatty acids. In addition, a band of an apolar substance was identified as a mixture of fatty acid ethyl esters. While showing growth, strains of M. furfur produced only small amounts of ethyl esters and free fatty acids. The growth kinetics of M. furfur and M. sympodialis were also different: for M. sympodialis, a clear lag phase was observed, possibly indicating the necessity of extracellular hydrolysis of the triglycerides. The significance of the synthesis of ethyl esters could not be clarified. For routine differentiation, this metabolic difference is only of limited usefulness because slight contamination of M. furfur strains with other lipophilic Malassezia species may lead to misinterpretation due to the high metabolic activity. These metabolic differences might be important in the pathogenesis of Malassezia infections.

Agar↗
PubMed1992

[Experiences with congener analysis of beverages without congeners].

Many alcoholic beverages contain no forensically relevant concentrations of congeners. Despite this fact they can be subject of a congener analysis. Another applicability of congener analyses are cases in connection with a differentiation between the short- or longterm ingestion of beverages containing 1-propanol and iso-butanol as congeners (e.g. beer or wine).

1-Propanol↗
PubMed1991

[An improved screening program for 160 pesticides].

A screening system for 170 pesticides is reported. The following analytical methods are used: TLC (corrected Rf-value), GLC (retention index) and UV-spectroscopy. Also quantitative aspects are mentioned when modern TLC-scanners are applied.

Chromatography, Thin Layer↗
PubMed1991

[Critical questions regarding standard deviation as a precision parameter of blood alcohol determination].

The relative absolute standard deviation, which was introduced for the control of the precision of blood alcohol-determinations by the BGH reveals, that according to technical rules the admissible standard deviation in the range of higher blood alcohol concentrations is exceeded despite the fact, that the width of the variation is still in the acceptable range. The standard deviation of 0.05% should therefore only be applied to the blood alcohol range up to 1.5%. As an alternative the coefficient of variation can be chosen for the precision control.

Alcohol Drinking↗
PubMedDate not supplied

[Detection of the cholinesterase inhibitor tacrine and its main metabolites].

Tacrine, a cholinesterase inhibitor for symptomatic treatment of minor to moderate dementia, and its primary metabolites 1-hydroxy-tacrine and 4-hydroxy-tacrine were studied by means of thin-layer chromatography, UV spectroscopy and gas-chromatography/mass spectroscopy. The analytical data (corrected hRf values, UV spectra in solution as well as reflectance spectra, high-pressure liquid chromatography data, GC retention indices and EI mass spectra) including various derivatization methods are described.

Biotransformation↗
PubMedDate not supplied

[Analytical confirmation of error in false positive amphetamine immunoassays and results].

Numerous urine samples were found to be positive when using a new amphetamine immunoassay (AxSYM). Confirmation analysis was carried out in a second laboratory at "reasonable prices" using a simple TLC-method with non specific ninhydrine detection and resulted in many "positive" confirmation findings. The GC/MS analysis clearly indicated the absence of amphetamine derivatives regularly encountered in forensic toxicology. The false-positive immunochemical findings may probably be caused by endogenous substances.

Amphetamine↗