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Biomedical subjects

W Heeschen

Publications and source records attributed to W Heeschen.

At least 19 recordsLinked to original sources
PubMed1996

Detection of inhibitors in milk by microbial tests. A review.

The demands concerning microbial inhibitor tests were subjected to marked changes during the last decades: It started with the claim of being able to detect contaminated milk which might cause problems during fermentation processes ('technological safety'). Due to the present day attention drawn to toxic and allergic hazards for numerous antimicrobials Maximum Residue Limits (MRLs) or safe/tolerance levels are fixed ('toxicological safety'). This means a variety of demands underlying permanent changes with respect to the 'detection pattern' which cannot be fulfilled by a single test. Within an Integrated Detection System microbial inhibitor tests play an important role as screening methods for those antimicrobials which can be detected with satisfactory sensitivities. This paper deals with some features of microbial inhibitor tests such as detection limits, performance susceptibility for interference factors, qualitative determination and standardization.

Animals↗
PubMed1991

Heavy metals, chlorinated pesticides and polychlorinated biphenyls in sudden infant death syndrome (SIDS).

The concentrations of lead in blood and of cadmium and mercury in kidney tissue were determined by atomic absorption spectrometry in cases in SIDS and a control group containing cases of known causes of death. SIDS cases were split into groups from urban and rural areas and areas highly polluted with lead and zinc (sites of lead and zinc works). Neither the concentration of lead in blood (median 26.5 to 50.0 micrograms/l), nor the concentration of cadmium (median 24.0 to 44.0 micrograms/kg ww) or mercury (43.0 to 69.0 micrograms/kg ww) showed significant differences between the groups. In addition the concentrations of persistent chlorohydrocarbons (hexachlorbenzene; alpha, beta and gamma hexachlorcyclohexane; heptachlorepoxide; dieldrine; total DDT; polychlorinated biphenyls) were measured in subcutaneous fatty tissue in SIDS cases from rural and urban areas and in a control group. These substances also showed no significant concentration differences in cases of SIDS.

Cadmium↗
PubMed1990

[Chlorinated hydrocarbons in seminal plasma and male fertility].

To determine the concentration of polychlorinated biphenyls (PCB), hexachlorobenzene (HCB) and gamma hexachlorocyclohexane (gamma HCH) in human seminal plasma, 176 ejaculates taken from 156 patients consulting the Dept. of Gynecology and Obstetrics of the RWTH Aachen for sterility were analysed gas-chromatographically. 77% of the examined samples exhibited different pathological sperm findings (OAT, AT, OA, A, O, T, P, K). Contrary to all our expectations the concentration of PCB, HCB and gamma HCH in the samples with normozoospermia were higher than in the samples with pathological sperm findings. The wives of 42.5% of the patients with normozoospermia exhibited no organically or endocrinologically reasons for sterility (idiopathic sterility). In this group (normal/idiopathic) the concentrations of the toxic agents were significant higher than in that group of patients with pathological sperm findings. In the group of couples with male normozoospermia and female organic/endocrinologic reasons for sterility (normal/organic) nearly the same concentrations of PCB, HCB and gamma HCH could be shown as in samples with pathological sperm findings. The concentrations of the toxic agents in the samples with the different pathological sperm findings were similar--independent of the kind of diagnosis. A correlation between the spermiogram parameters motility, morphology and density and the concentration of PCB, HCB and gamma HCH in the seminal plasma could not be shown.

Hexachlorobenzene↗
PubMed1990

[Demonstration of chlorinated hydrocarbons in follicular secretions].

To determine the concentration of HCB, HCH and PCB in human follicular fluid, 315 preovulatory follicular taken from 45 patients and aspirated by transvaginal follicular puncture were analysed with the aid of gas chromatography. We distinguished follicular fluid without oocytes and follicular fluid with oocytes. Again the latter is subdivided into follicular fluid containing secondarily fertilized oocytes and non-fertilized oocytes. There are great differences in HCB (0.08 - 1.87 ng/ml), HCH (0.05 - 1.0 ng/ml) and PCB (0.28 - 2.11 ng/ml) concentrations, varying even in the follicles of the same patient. Contrary to all our expectations we did not find any significant difference in the HCB, HCH and PCB concentration of the different follicular fluids. A direct influence of these substances on the fertilization of oocytes in IVF-ET-procedure could not be established.

Biphenyl Compounds↗
PubMed1976

[Residues of chlorinated hydrocarbons in milk and milk products - situation and evaluation (author's transl)].

Residues of the most varied chemical substances can be found in milk and in milk products. For the transfer into milk such factors as fat solubility, persistance with respect to metabolic processes and accumulation capacity in certain organic systems are of particular importance. For the description of the situation with respect to residues of chlorinated insectides the results of analyses obtained in 20 supply areas of the German Federal Republic are presented and interpreted. In 1974 the following mean values were found (fat basis): alpha-HCH 0.04, gamma-HCH 0.072, heptachloro-epoxide 0.024, dieldrin 0.021 and DDT 0.20 ppm. These mean values are far below the max. quantities legally permissible and in no way constitute a toxicological risk (referred to ADI). In the German Federal Republic the concentrations of hexachlorobenzene in some cases reach the permissible max. quantity of 0.5 ppm on a fat basis. There is reason to assume that this substance finds its way into the milk not only via its application as a fungicide but probably also via a number of other, in part unknown, sources of contamination in or on vegetable products. With PCB (polychlorinated biphenyls) average concentrations from 0.2 to 0.3 ppm must be expected to be present in milk and milk products (fat basis). At present a toxicological interpretation of the values found is hardly possible.

Animals↗