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Biomedical subjects

C Rappe

Publications and source records attributed to C Rappe.

At least 55 records · Page 3Linked to original sources
PubMed1985

Polychlorinated biphenyls, dibenzofurans and quaterphenyls in toxic rice-bran oil and in the blood and tissues of patients with PCB poisoning (Yu-Cheng) in Taiwan.

A mass outbreak of poisoning occurred in central Taiwan in 1979 due to the ingestion of rice-bran oil contaminated with polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs) and quaterphenyls (PCQs). The incident was called PCB poisoning or Yu-Cheng in Taiwan. The major PCB and PCDF congeners in the toxic oil and in the blood and tissues of the poisoned patients were characterized by gas chromatography and gas chromatography-mass spectrometry using highly efficient glass capillary columns. The levels of toxic agents in the rice oil samples collected from the factory and school cafeterias and the families of the poisoned patients are in the range of 53 to 99 ppm, 0.18 to 0.40 ppm and 25 to 53 ppm for PCBs, PCDFs, and PCQs, respectively. The blood samples of 165 patients collected 9 to 18 months after the onset of poisoning contained 10 to 720 ppb of PCBs, with a mean value of 38 ppb. The blood samples of 10 patients collected 9 to 27 months after poisoning contained 0.02 to 0.20 ppb of PCDFs. Comparative rates of elimination of some PCB congeners from the blood of patients were studied. Various tissues from a patient who died 2 years after poisoning were analyzed for PCBs, PCDFs and PCQs. The intestinal fat contains the highest level of PCBs, while the liver contains the highest concentration of PCDFs. The PCB congeners retained in the tissues either do not have adjacent unsubstituted carbon atoms or have a pair at ortho-meta positions of the biphenyl ring. The major PCDF congeners retained in the tissues were 1,2,3,4,7,8-hexachloro-DF, 2,3,4,7,8-pentachloro-DF and 1,2,4,7,8-pentachloro-DF. The former two congeners, especially 2,3,4,7,8-pentachloro-DF, are very toxic PCDFs; they may play important roles in the etiology of Yu-Cheng.

Benzofurans↗
PubMed1985

Strategies and techniques for sample collection and analysis: experience from the Swedish PCB accidents.

A series of polychlorinated biphenyl (PCB) fires and explosion in PCB-filled capacitors and transformers is discussed. A sampling program followed by isomer specific determination of trace levels of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) is described. Data from a series of Swedish PCB accidents are given. In addition to PCDFs and PCDDs, we have also found a series of polychlorinated biphenylenes (PCBPs). Cleaning of contaminated areas was done by vacuum cleaning followed by high pressure washing.

Accidents, Occupational↗
PubMed1985

Analysis of polychlorinated dibenzofurans, dioxins and related compounds in environmental samples.

The analysis of polychlorinated dibenzofurans (PCDFs), dibenzo-p-dioxins (PCDDs) and to some extent biphenylenes (PCBPs) by high-resolution gas chromatography (HRGC) and mass spectrometry is described. Electron-impact (EI) and negative chemical ionization (NCI) mass spectrometry were used, and their application in environmental analyses documented. NCI shows increased sensitivity to all PCDFs and PCDDs except for 2,3,7,8- and other tetra-CDD isomers. The identification of the various PCDFs and PCDDs, specifically the identification of the toxic and hazardous 2,3,7,8-substituted isomers is emphasized; the unambiguous identification of all 2,3,7,8,-substituted PCDDs is documented. The application of HRGC and mass spectrometry to isomer-specific analyses of samples of aquatic species from the Baltic and the Great Lakes is shown. Results from this and previous studies indicate PCDF and PCDD residues in these organisms including significant levels of 2,3,7,8-substituted isomers. These aquatic species apparently show preferential retention or reduced metabolization rates for these toxic isomers. The results of samples from the Baltic indicate a contamination primarily due to PCDFs. The origin of this contamination seems complex and related to PCBs as well as chlorophenols. PCDF and PCDD isomer distribution patterns from analyses using HRGC and mass spectrometry aid in the identification of origin, sources and elucidation of routes of formation of these compounds. These methods are indispensable in taking measures to reduce future contaminations and to protect our environment.

Benzofurans↗
PubMed1985

Assessment of human exposure to polychlorinated dibenzofurans and dioxins.

Fires, explosions and other accidents in polychlorinated biphenyl (PCB)-filled equipment can result in possible exposure of firemen, cleaning personnel and regular workers. Inhalation, dermal exposure and ingestion are the possible routes of exposure. An indirect assessment of the exposure can be made by analyses of wipes, air and water samples and clothes. A direct assessment of exposure can be made by analyses of blood samples, adipose and other tissue samples, feces and bile.

Adipose Tissue↗
PubMed1980

Occupational exposure to N-nitroso compounds.

N-Nitrosodiphenylamine is used as an additive in the rubber industry. This N-nitrosamine has not been associated with carcinogenic effects in laboratory animals. However, it can serve as a powerful transnitrosation agent, reacting with amines present in the rubber mixture to form other N-nitrosamines; e.g., N-nitrosodibutylamine from di-n-butylamine and N-nitrosodimethylamine from tetramethylthiuram disulfide. Di-n-butylamine and tetramethylthiuram disulfide are both used as additives in the rubber industry.

Air Pollutants↗
PubMed1979

Analysis of some older Scandinavian formulations of 2,4-dichlorophenoxy acetic acid and 2,4,5-trichlorophenoxy acetic acid for contents of chlorinated dibenzo-p-dioxins and dibenzofurans.

Ten samples of older formulations of 2,4,5-trichlorophenoxy acetic acid and 2,4-dichlorophenoxy acetic acid used in Sweden were analyzed for chlorinated dibenzo-p-dioxins and dibenzofurans. The analyses were performed with gas chromatography/mass spectrometry with a high resolution glass capillary column for maximum isomeric separation and sensitivity. The detection limit was 0.01-0.05 ppm. The amounts of contaminants were of the same order of magnitude as that found earlier in European samples with later production dates (late 1960s and 1970s).

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1978

Hepatomas and other neoplasms in the atlantic hagfish (Myxine glutinosa): a histopathologic and chemical study.

M. glutinosa is a cyclostome, living in the mud in seawater of high salinity. It probably is a stationary scavenger feeder. About 28,000 hagfish from the Gullmar Fjord were examined during a 5-year period for the occurrence of tumors. Hepatomas were found to be predominant neoplasm, observed at a frequency that decreased from 5.8% in 1972 to 2.9% in 1973 and finally to 0.6% in 1974--76. Islet cell hamartomas and frank neoplasms decreased from 0.5% in 1972 to less than 0.1% in 1973--76. Occasional subcutaneous and mesenterial neoplasms were also observed during 1972--74. In hagfish caught 12 km out in the open sea, the hepatoma incidence decreased from 2.8% in 1972 to 0.9% in 1974. Given this background, it is possible that pollution of the Gullmar Fjord by carcinogenic substances with low biodegradability has occurred until 1972, and this pollution could be of etiologic significance for these hagfish tumors. In fact, the use of PCBs became prohibited by law in Sweden in 1971--72. Severe restrictions were also introduced for the use of chlorinated pesticides, notably DDT, and associated substances (DDD, DDE). Preliminary analyses for the presence of PCBs, DDT (and its metabolites), and aflatoxins (the notorious hepatocarcinogen) were performed by gas chromatography and thin-layer chromatography. Livers (with and without neoplasms) from hagfish caught inside the threshold of the fjord contained about 5 mg/kg of wet weight of PCBs and about 0.1--0.4 mg/kg of dry weight of DDT, DDD, or DDE, whereas those from hagfish caught in the open sea had a much lower PCB concentration (about 0.2 mg/kg of wet weight). No PCBs and no chlorinated pesticides were found in analyses of the mud at the catching site. High PCB concentrations (3 mg/kg of wet weight) were, however, observed in livers from cod living in the Gullmar Fjord, and it was proposed that bony fish may be the source of hagfish liver PCBs. PCB chromatograms of hagfish livers differed from those of PCB standards and cod liver. This strange pattern, which was not seen in livers from hagfish caught in the open sea, might be explained by an unusual mode of metabolization. The assays for aflatoxins gave completely negative results.

Adenoma, Bile Duct↗
PubMed1976

Use of chlorophenols as fungicides in sawmills.

Several commercial formulations of chlorophenols used as fungicides in sawmills were found to contain impurities, some of which are known to be much more toxic than the main products. The most frequent impurities were chlorinated phenoxyphenols, chlorinated diphenyl ethers, chlorinated dibenzofurans, and chlorinated dibenzodioxins. Samples of wood dust from several positions in two Swedish sawmills were analyzed. The results suggest that the impurities in the chlorophenol formulations are enriched in the work environment in relation to the chlorophenols themselves, probably because of the low volatility and high chemical stability of the impurities. The effect of various methods of fungicide application on the work environment is discussed.

Fungicides, Industrial↗