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Biomedical subjects

P J Schepens

Publications and source records attributed to P J Schepens.

At least 19 recordsLinked to original sources
PubMed2000

Comparison of persistent organic pollutant residues in serum and adipose tissue in a female population in Belgium, 1996-1998.

This study was performed to determine and compare persistent organic pollutant (POP) levels in different matrices in a female population. A total of 96 serum and 46 adipose tissue samples were collected from infertile women (n = 101) attending Centers for Reproductive Medicine in Belgium from 1996 to 1998. Gas chromatography with electron-capture detection was used to quantify residue levels on a lipid basis of seven organochlorine pesticides (OCPs) and seven polychlorinated biphenyls (PCBs). There was a strong association between adipose tissue and serum residues. The adipose tissue levels of CB-138, 153, 180 and p,p'-DDE were explained by the serum residues. Besides, the accumulation pattern for CB-153 and CB-180 in serum and adipose tissue are mirror images of each other.

Adipose Tissue↗
PubMed2000

Comparison of chemical-activated luciferase gene expression bioassay and gas chromatography for PCB determination in human serum and follicular fluid.

We assessed exposure to dioxin-like compounds using chemical and bioassay analysis in different matrices in a female population. A total of 106 serum and 9 follicular fluid samples were collected from infertile women attending Centers for Reproductive Medicine in Belgium from 1996 to 1998. Major polychlorinated biphenyl (PCB) congeners were quantified by chemical analysis using gas chromatography with electron-capture detection, and the chemical-activated luciferase gene expression (CALUX) bioassay was used to determine the total dioxin-like toxic equivalence (TEQ) of mixtures of polyhalogenated aromatic hydrocarbons present in body fluids, such as serum and follicular fluid. To the best of our knowledge, this is the first investigation to determine TEQ values by the CALUX bioassay in follicular fluid. The TEQ levels in both matrices are well correlated (r = 0.83, p = 0.02). As the chemical and bioassay analysis executed in this study do not cover the same span of polyhalogenated aromatic hydrocarbons, we did not expect totally correlated results. Moreover, the sample workup and quantification of the analytes differed completely. Nonetheless, the TEQ values in human extracts correlated well with the sum of four major PCB congeners chemically determined in both serum and follicular fluid. These results indicate that the CALUX bioassay may serve as a simple, relatively inexpensive prescreening tool for exposure assessment in epidemiologic surveys.

Adult↗
PubMed1999

Improved sample preparation method for selected persistent organochlorine pollutants in human serum using solid-phase disk extraction with gas chromatographic analysis.

An improved solid-phase extraction (SPE) method was developed to isolate and concentrate trace levels of selected POPs (persistent organochlorine pollutants) in human serum prior to GC-MS in SIM mode or GC-ECD quantitation. The extraction involves denaturation of serum proteins with formic acid, SPE using C18 Empore disk cartridges, followed by elimination of lipid interferences using a sulfuric acid wash of the eluate. Use of the SPE disk improved assay throughput and gave a cleaner analytical matrix compared with previously reported solid-phase and liquid-liquid extraction techniques. The extraction method provided consistent recoveries at three fortification levels using 13C12 PCB 149 as internal standard. Recoveries ranged from 48 to 140% for organochlorine pesticides (6.25, 12.5 and 25 ng/ml) and 71 to 126% for polychlorinated biphenyls (0.625, 1.25 and 2.5 ng/ml).

Blood Proteins↗
PubMed1999

The relation between levels of selected PCB congeners in human serum and follicular fluid.

Individual congener and total PCB concentrations were determined in serum and follicular fluid obtained from women undergoing assisted reproductive technologies (in-vitro fertilization and embryo replacement). Although the mean individual PCB levels revealed varying degrees of contamination, the results fall in the same range as that observed by other investigators. Except for PCB 118, correlations between levels in serum and follicular fluid were strong, and statistically significant at p < 0.05. Moreover PCB 153, a major and very stable PCB congener has been shown to correlate to the total amount of PCBs (r = 0.994, and r = 0.987, for serum and follicular fluid, respectively). The same accumulation patterns of PCBs for serum and follicular fluid have been observed.

Adult↗
PubMed1998

Drugs of abuse and alcohol in weekend drivers involved in car crashes in Belgium.

STUDY OBJECTIVE: To determine levels of alcohol and drugs of abuse in weekend drivers injured in car crashes. METHODS: This study was the first systematic drug and alcohol testing of blood and urine samples of drivers injured in weekend car crashes in Belgium. Five collaborating hospital in Flanders participated. All injured weekend drivers admitted to the emergency units from July 1, 1994, to June 30, 1995, were included in the study sample. Sampling times were from Friday at 8 PM to Monday at 8 AM. RESULTS: Of the 211 injured drivers, 47.9% had positive test results for screenings for drugs or alcohol; 35.5% only for alcohol, 6.6% only for drugs, and 5.7% had positive results for both alcohol and drugs. Of the 87 weekend drivers with positive alcohol test results, 8% had a blood alcohol concentration (BAC) level below 80 mg/dL, 25.3% had a concentration between 150 and 190 mg/dL, and 39% had a BAC of 200 mg/dL or greater. There seems to be a consistent association between the consequences of the weekend crashes and the use of alcohol, drugs, or both. More than 50% of those who had negative results for drugs and alcohol could leave the hospital within 24 hours after their car crash. For the majority of those with positive findings for alcohol only or for drugs and alcohol (respectively, 72% and 78%), hospitalization in a general hospital unit or ICU was necessary. CONCLUSION: The results suggest that testing drivers for use of alcohol alone is insufficient.

Adult↗
PubMed1997

An unusual poisoning with the unusual pesticide amitraz.

Amitraz, 1,5 di-(2,4-dimethylphenyl)-3-methyl-1,3,5-triaza-penta-1,4-diene, a formamidine pesticide, is used worldwide. It causes side-effects in animals that resemble those caused by pure alpha 2-adrenergic agonist drugs such as clonidine. Data on poisonings in humans are scanty. We report on a case of human poisoning with amitraz with typical signs of alpha 2-adrenoreceptor stimulation.

Blood Pressure↗
PubMed1996

Acute poisoning with amphetamines (MDEA) and heroin: antagonistic effects between the two drugs.

A case of oral ingestion of large doses of both the amphetamine-derivative 3,4-methylene dioxyethamphetamine (MDEA) and heroin is reported. Despite high serum levels of both drugs, the patient did not present with the classic signs and symptoms normally seen during intoxication with these drugs. The patient recovered after symptomatic treatment. The possibility that opposite pharmacological properties of the two drugs prevented the patients death is discussed.

3,4-Methylenedioxyamphetamine↗
PubMed1995

A 2,4-dichlorophenoxyacetic acid induced fatality.

This paper reports on a fatal intoxication by oral ingestion of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). At admission, the victim was unconscious. His condition deteroriated rapidly with blood loss from his mouth and nose. Since the cause of this condition was not known, gastroscopy was performed and haemorrhagic mucosa was observed in the mouth, oesophagus and stomach. Gastric contents (removed by lavage), urine and blood were submitted for toxicological analysis. Unfortunately, within 3 h of admission (about 5 h following ingestion of the toxin) profound cardiogenic shock developed and the patient died. The identity of the toxic xenobiotic was revealed by gas chromatography-mass spectrometry. Analytical quantification of the herbicide was performed by acid extraction prior to gas chromatographic examination using electron capture detection. His blood level of 2,4-D was 192 mg l-1.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1993

Human pentachlorophenol poisoning.

Pentachlorophenol (PCP) was, and still is, one of the most frequently used fungicides and pesticides. Its toxicity is due to interference with oxidative phosphorylation. Acute and chronic poisoning may occur by dermal absorption, inhalation or ingestion. Chronic poisoning occurs mainly in sawmill workers or people living in log homes treated with PCP-containing wood protecting formulations. Quantitative determination of PCP in urine and serum is useful to detect occupational or subclinical exposure. The clinical features of acute and chronic PCP poisoning can be classified systematically into effects on the skin, metabolism (fever), the haematopoietic tissue, the respiratory system, the central and peripheral nervous system, the kidney and the gastrointestinal tract. Although PCP is not classified as a human carcinogen, some epidemiological observations suggest that exposure to chlorophenols in general and PCP solutions in particular may result in an increased risk for certain malignant disorders such as nasal carcinoma and soft tissue sarcoma. There is concern that contamination of PCP-solutions with products such as chlorodibenzo-p-dioxins is the real cause of this suspected carcinogenicity. No specific antidote exists for the treatment of (acute) PCP poisoning. The basis of the treatment of acute poisoning is intensive supportive care with prevention of dangerous rise in temperature. Use of PCP-based products as indoor wood preservatives poses an unacceptable risk to human health.

Carcinogenicity Tests↗
PubMed1991

Pentachlorophenol concentrations in human cerebrospinal fluid.

Pentachlorophenol (PCP) is a widely applied insecticide and fungicide, particularly in wood preservation. Significant amounts of this compound have been reported in human serum, adipose tissue and urine. PCP is even found in people not occupationally exposed to this toxin or not living in PCP-treated log-houses. Substantial concentrations of this possible neurotoxic agent were detected in the cerebrospinal fluid (CSF) of 16 neurologic patients as measured by a high resolution gas chromatographic method using electron capture detection. This is the first report on PCP levels in (human) CSF. The observed level in CSF ranged from 0.24 up to 2.03 micrograms/L (ppb), with an average value of 0.75 +/- 0.49. The cerebrospinal fluid level did not correlate with the serum PCP concentration nor with the protein level of the cerebrospinal fluid.

Adult↗
PubMed1989

Positive confirmation of identity of doping agents using gas chromatography-mass spectrometry with Fourier transform infrared spectrometry.

During the past two decades, the use of retention times in gas chromatography has been augmented by mass spectrometric data. By providing both the retention indices and spectrometric data, this technique has greatly improved gas chromatographic identification analysis. However, although gas chromatography-mass spectrometry has become pre-eminent, several drawbacks still remain. The mass spectral library often gives erroneous identifications when concentrations near the detection limit are analysed, when gas chromatographically interfering substances are present, or when structural isomers or compounds exhibiting identical retention behaviour are analysed. Linked with gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy can be a powerful complementary technique in peak identification analysis. Some spectral data to illustrate this point are presented.

Animals↗
PubMed1989

Quantitative determination of nitroglycerin by capillary gas chromatography-electron capture detection.

A rapid and sensitive capillary gas chromatographic method based on the one described by Noonan et al. [1] was used to evaluate the nitroglycerin content in serum samples of healthy volunteers, who had orally received a special preparation of the drug (Nisconitrine 6.5, Bio-Therabel). Concentrations were monitored up to 12 h after administration. In accordance with other literature data [2], no detectable amounts of the mother compound were found (limit of detection: 50 pg ml-1). Yet, significant amounts of the active metabolites, 1,2- and 1,3-dinitroglycerine could be demonstrated. Due to the low mass spectrometric response (electron impact ionization) of the different nitroglycerins, positive confirmation of the results with GC-MS was not possible. However, the concentrations reported here do agree with literature data [2], i.e. the ng ml-1 level.

Capsules↗