Biomedical subjects

C Rappe

Publications and source records attributed to C Rappe.

62 records · Page 4Linked to original sources

PubMedDate not supplied

Peroxidase-catalyzed oxidation of chlorophenols to polychlorinated dibenzo-p-dioxins and dibenzofurans.

Chlorophenols are transformed in vitro to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by peroxidase-catalyzed oxidations. This is demonstrated with bovine lactoperoxidase as well as horseradish peroxidase, and with 3,4,5- and 2,4,5-trichlorophenol (TrCP). The yield of total PCDD/Fs with lactoperoxidase was 11 micrograms per g 345-TrCP and 10 micrograms per g 245-TrCP, of which 2,3,7,8-substituted PCDD/Fs constituted 8.5 and 2.2 micrograms/g, respectively, corresponding to 0.85 and 1.2 micrograms/g of Nordic TCDD-equivalents.

Animals↗

PubMedDate not supplied

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) in food samples collected in southern Mississippi, USA.

In 1994, we analyzed 43 foodstuff samples from local supermarkets in southern Mississippi, USA, for PCDD/PCDF. 2,3,7,8-Cl4DD could be quantified in 31 of these samples. On a lipid basis, levels in meat (0.53-1.10 pg I-TEQ/g) and dairy products (0.42-1.10 pg I-TEQ/g) were slightly lower than those reported from other industrialized countries. While levels in dairy samples from the United States and Europe are comparable, there is a difference in the contribution of individual congeners to the I-TEQ: for example, in milk samples from Germany approximately 40% of the I-TEQ is due to the presence of 2,3, 4,7,8-Cl5DF while in the Mississippi samples this congener only contributes 16%. The highest concentrations of PCDD/PCDF in our study were detected in the farm-raised catfish (10.2-27.8 pg I-TEQ/g). A unique finding was that in addition to the 2,3,7,8-substituted PCDD/PCDF the catfish samples contained many non-2,3,7,8-substituted congeners. This is unusual because vertebrate animals selectively eliminate or metabolize the non-2,3,7,8-substituted congeners.

Benzofurans↗

PubMedDate not supplied

PCDD, PCDF, and PCB in farm-raised catfish from southeast United States--concentrations, sources, and CYP1A induction.

Nine catfish fillets, three catfish nuggets, two feed samples, and one pond sediment were analyzed for PCDD, PCDF, and PCB. Farm-raised catfish from Mississippi, Alabama, and Arkansas contained significant levels of 2,3,7,8-substituted PCDD and PCDF. In addition, a large number of non-2,3,7,8-substituted congeners were present in all samples. The catfish fillets and catfish nuggets also contained high concentrations of dioxin-like PCB, as well as a number of non-dioxin-like PCB. The TEQ based on PCDD and PCDF ranged from 9.5 to 43.0 pg/g lipid and the TEQ based on PCB ranged from 0.45 to 4.9 pg/g lipid for all catfish samples. The dioxin-like PCB contributed 4-16% to the total TEQ (PCDD/PCDF/PCB) for the catfish samples. The major source for the PCDD, PCDF, and PCB appears to be from feed and not from pond sediment. Immunoreactive CYP1A protein was elevated 2.5 fold in the pond-raised catfish compared to the aquarium-raised one. The results of this study suggest that the PCDD/PCDF are more important than the PCB in the CYP1A induction.

Agriculture↗

PubMedDate not supplied

Concentrations and biomagnification of 17 chlordane compounds and other organochlorines in harbour porpoise (Phocoena phocoena) and herring from the southern Baltic Sea.

Four species of harbour porpoise (Phocoena phocoena) and one herring (Clupea harengus) sample from the southern Baltic Sea were analysed in an attempt to study the concentration and biomagnification of 17 chlordane related compounds (CHLs) including 12 components present in technical chlordane, the toxic metabolites oxychlordane and cis-hepatchlorepoxide and the photoconversion products photoheptachlor and two photo-cis-chlordanes. The concentration and biomagnification ability of CHLs were also compared to other organochlorines such as HCHs (hexachlorocyclohexanes), hexachlorobenzene, DDTs, dieldrin, mirex and PCBs (polychlorinated biphenyls). Of the CHLs analysed, 16 were detected in porpoise and 15 in herring including the photoconversion products. In both species the highest concentrations were found for PCBs and DDTs. The concentration of PCBs and CHLs in porpoise varied from 5700-16,000 and 470-1250 ng/g lipid, and in herring from 1300 and 49 ng/g lipid, respectively. The biomagnification factor (BMF: concentration in organism/concentration in food; all lipid normalized) in porpoise was found to be high for CHLs followed by dieldrin and lowest for HCHs. Among the CHLs, a big variation of BMF (BMF range approximately 1-50) was found e.g., the nonachlorinated compounds biomagnified to the highest degree followed by cis-heptachlorepoxide, photoheptachlor and oxychlordane.

Animals↗

PubMedDate not supplied

Search for chlorobornanes in river sediments and in influents and effluents.

In 1997, we collected nine river sediment samples, including one duplicate, from above and below three pulp and paper mills on the Wisconsin River in Wisconsin, USA, and one mill on Beaver Dam Creek in Ontario, Canada. We also obtained twenty split sediment samples from the Wisconsin River that were collected by the US EPA in collaboration with Indiana University. Finally, we collected influent and effluent samples from eight pulp and paper related industries in the US and Canada. We analyzed all sediment and water samples for hexa- through decachlorobornanes. We did not detect any chlorobornanes in most of the sediments. When chlorobornanes were detected, the concentration in sediments below pulp mills were similar to or less than in those from above the same mills. Chlorobornanes could not be detected in any of the influent or effluent samples. Thus, pulp and paper mills and relate facilities are not a source of chlorobornanes.

Camphanes↗

PubMedDate not supplied

Organochlorine compounds in the Gulf of Bothnia: sediment and benthic species.

Surface sediment, amphipods (Monoporeia affinis), isopods (Saduria entomon) and fourhorn sculpins (Oncocottus quadricornis) were collected at two coastal stations in the Gulf of Bothnia, one in the Bothnian Bay and the other in the Bothnian Sea. The objective was to study the concentrations, composition profiles, bioaccumulation features and spatial differences of organochlorine compounds such as hexachlorocyclohexanes (HCHs), DDTs, hexachlorobenzene (HCBz), chlordanes (CHLs), dieldrin, Mirex and polychlorinated biphenyls (PCBs). All groups of compounds were found in every sample investigated, with the exception of Mirex that was not detected in the sediment samples. The concentrations for e.g. PCBs and CHLs ranged from 700 to 2400 and 70 to 400 ng/g lipid in the specimens. For the corresponding sediments the results were 9.0-9.3 ng/g dw for PCBs and 0.54-0.57 ng/g dw for CHLs, respectively. Bioaccumulation differences between the species with regard to both degree of and type of compound were observed. The highest accumulation potential was found for the cyclodiene compounds including CHLs and Mirex in isopod. Finally, there were only small concentration and bioaccumulation differences between the two stations.

Animals↗

PubMedDate not supplied

Rapid anaerobic degradation of toxaphene in sewage sludge.

We studied the degradation of technical toxaphene in anaerobic sewage sludge from a municipal waste water treatment plant. Chlorobornanes, chlorocamphenes and related compounds were rapidly degraded, with degradation rates in the order of decachloro>nonachloro>octochloro>heptachloro approximately = hexachloro compounds. The half-lives of individual congeners ranged from <1 day to several days. We also studied the degradation of technical toxaphene in previously sterilized sludge (control), and found it was slower than in the anaerobic sludge. The chlorobornanes that degraded most rapidly in the non-sterilized anaerobic sludge were those with gem chloro substitution on the 6-member carbon-ring, including the toxic congeners, Toxicant A and B. Non-gem chloro substituted congeners, like the biologically persistent P26 and P50, also degraded, but less rapidly. Toxaphene degradation in sewage sludge proceeded primarily via reductive dechlorination, leading to HxSed, HpSed, TC2 and other persistent metabolites. Enantioselective determinations indicated little, if any, enantioselectivity in the formation and/or degradation of these compounds. The isomer and enantiomer profiles of the hexa-, hepta-, and octachlorobornanes are similar to those observed in sediment from the Baltic Sea, suggesting that technical toxaphene is the source of these compounds and that its composition was changed via similar anaerobic degradation pathways.

Anaerobiosis↗

PubMedDate not supplied

Biochemical, neuropsychological, and neurological abnormalities following 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure.

Presented herein are the results of follow-up examinations of 13 workers performed in 1996--30 yr following 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) intoxication in a herbicide production plant. In these workers, the current mean plasma level of 2,3,7,8-TCDD, measured by high-resolution gas chromatography/high-resolution mass spectrometry, was 256 pg/gm lipid (range = 14-760 pg/gm lipid). This mean value corresponded to an estimated concentration of approximately 5,000 pg/gm plasma fat that existed about 30 years ago. Such a mean plasma level indicates that this group was one of the most heavily exposed groups to 2,3,7,8-TCDD described in the literature. Patients with persistent chloracne had significantly higher plasma levels of 2,3,7,8-TCDD than persons without chloracne. A significant, positive correlation was found between plasma levels of 2,3,7,8-TCDD in 1996 and levels of cholesterol and plasma lipids that existed since 1974. During 1996, there was a significant positive correlation between 2,3,7,8-TCDD and levels of beta-lipoproteins, cholesterol, and triglycerides. Also in 1996, significant correlations were found between neuropsychological variables and plasma levels of 2,3,7,8-TCDD. Other significant correlations were observed between neuropsychological variables and (1) the highest levels of triglycerides (i.e., since the year 1989), (2) levels of triglycerides in 1996, (3) levels of cholesterol at the first examination (i.e., 1969-1970), (4) highest level of cholesterol since the year 1969, and (5) cholesterol levels in 1996. Such correlations are biologically plausible, and they provide evidence of impaired cognitive performance (i.e., memory first), with a concurrent increase of plasma lipid levels. Abnormal electromyography, electroencephalography, and visual evoked potentials were observed in 23%, 54%, and 31 %, respectively, of former workers. Abnormal electroencephalography findings occurred more frequently in workers who had 2,3,7,8-TCDD blood levels that exceeded 200 pg/gm plasma fat than in workers with 2,3,7,8-TCDD values lower than 200 pg/gm plasma fat (p < .025). Frequency of polyneuropathic EMG abnormalities decreased from 38% in the 1970s to 23% in 1996. Improvement of conduction velocity in the tibial nerve was statistically significant (p < .05).

Chemical Industry↗