Well, to be fair, only the abstract is available online unless you have a subscription to the International Journal of Toxicology, and so you would have to get the full article to judge the methods. I'm on campus at OU Medical Center and we don't have online access to this journal. So, from only the abstract I can tell the following:
1. This was a study on a human kidney cell line, not rats. 2. Their measurements of toxicity were apoptosis and morphological changes. Apoptosis is programmed cell death: exposure of cells to some chemicals or toxins can trigger a suicide response so that they die after a number of specific physiological changes. Kidney cells are considered an important model system since you would like to avoid apoptosis in your kidneys. :-) Apoptosis is often accompanied by visible changes is the cells under the microscope. 3. Their main point was the differences in triggering apoptosis by two different forms of PCB and the role of the enzyme caspase-3 in these differences. 4. My guess is that the incubation periods were less than two weeks and possibly less than one week, given that we are dealing with cultured human cells. It is not at all unusual for method details to be omitted from the abstract in biological sciences: often journals have strict word limits on abstracts. So, nothing is being hidden; you would just have to get the full article. My interest would be to see: 1) the doses used and whether these are relevant to known human occupational exposures, and 2) whether the differences seen in the study were significant statistically. Even then you gotta look carefully at the results. As I tell my students, if something doubles your risk of being run over by a bus from 1 in a million to 2 in a million, you probably still will cross the street. Finally, I'm a microbiologist and no expert on PCBs. However, I can tell you that your risk of death is probably higher from exposure to influenza. 72/73 and sorry for the dissertation on toxicology, Mike N5JKY On Mar 2, 2010, at 4:18 PM, Milt, N5IA wrote: > And I have to totally agree with Ken. I have the same experience. > Career 40+ years in power distribution. > > If you really want the "rest of the story", do a search on Google or > other search engine for "Death of Humas by PCB Polychlorinated > Biphenyl's". I don't think you will find anything. > > Feeding hundreds of times a normal "dose" of PCB to laboratory rats > or a LOOOOONG time period showed the following: Quote > > "Polychlorinated biphenyls (PCBs) are among the most widespread and > persistent pollutants in the global environment. Coplanar and > noncoplanar PCBs have been shown to cause congener-specific > apoptosis mediated neurotoxicity in rats. > > Very few, if any, such studies have been reported on human renal > cell toxicity. The authors report here caspase-dependent or caspase- > independent renal toxicity, as measured by apoptotic death induced > by PCBs, depending on the planarity of congeners PCB-77 (coplanar) > and PCB-153 (noncoplanar) in human kidney cells (HK2) in vitro. The > authors have combined morphological and biological techniques to > discover the relevance of apoptosis in renal proximal tubule cell > death induced by these two PCB congeners. Treatment with both PCB > congeners caused accelerated apoptosis in a time- and concentration- > dependent manner. > > Based on our findings using human kidney (HK2) cells, there was more > apoptosis-mediated loss of cell viability by non-ortho-substituted > PCB-77 when compared to PCB-153. A significant increase of caspase-3 > expression through immunoblot studies showed the involvement of > apoptosis by PCB-77 compared to none by PCB-153. The broad-spectrum > caspase inhibitor z-VAD-fmk showed increased cell death when treated > by PCB-153, but not by PCB-77, confirming that caspase inhibitor > induced a switch in the mode of cell death. It is reasonable to > assume that apoptotic cell death in the renal proximal tubule cells > treated by PCBs may have both caspase-dependent and caspase- > independent pathways." > > They don't quote the amount of TIME and the CONCENTRATION. I cannot > find record of, and have never heard of, a human being suffering > death or even sickness due to normal exposure to fluids containing > PCBs. > > However, by the Stockholm Convention worldwide (2001) and the US > Congress in the USA (1979), billions of dollars have been spent > testing, labeling, replacing and buring or destroying power > distribution equipment which were "contaminated" with but a few PPM > of PCB in the dielectric fluids. > > The capacitors, transformers and oil which were removed from the > distribution system which I worked for are now buried deep inside a > rock mountain in Nevada at a great expense. > > And the fluids which replaced the PCB fluids cost a whole lot more > and were less effective (less dielectric strength). > > Do your own research and draw your own conclusions regarding PCBs. > YMMV. > > 73 de Milt, N5IA > > > > ----- Original Message ----- > From: "Ken Kopp" <[email protected]> > To: "Dave New, N8SBE" <[email protected]>; "Ken Nicely" <[email protected] > > > Cc: <[email protected]> > Sent: Tuesday, March 02, 2010 12:44 PM > Subject: [Elecraft] OT: Transformer oil in DL's > > >> As a (retired) career power company employee I can say with >> reasonable certainty that the "transformer oil" that was available >> to --most-- scrounging hams since the introduction of the Cantenna >> was -unlikely- to contain PCB's. >> >> At least in the circumstances familiar to me, PCB-containing >> transformer oil was mostly long gone by the time the Cantenna >> was introduced. It was certainly gone "as new" out of the barrel, >> but did remain in transformers already in place, but few if any >> hams received their oil from a transformer. (:-) >> >> It doesn't "make it right", but we had transformer shop employees >> that literally stood chest deep in the stuff inside large substation >> transformers when they were overhauled or a tap needed changed. >> >> 73! Ken Kopp - K0PP >> [email protected] > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Michael McShan N5JKY Oklahoma City, OK [email protected] SKCC #85 FISTS #2626 QRP ARCI #9057 NAQCC #470 EM15fl ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
