Monday, 14 November 2011
Lung Asbestos Content in Chrysotile Workers with Mesothelioma
The role of chrysotile asbestos in the genesis of mesotheliomas in humans is disputed. We analyzed the asbestos content of the lung in 6 long-term chrysotile miners and millers who had pleural mesotheliomas. In five patients, only chrysotile ore components (chrysotile and tremolite/actinolite/anthophyllite types of amphibole asbestos) were found, while the sixth patient presented both chrysotile ore components and amosite, a type of asbestos that is not derived from the mining process. The mean number of fibers/g dry lung for the 5 patients with mesothelioma containing only chrysotile ore components was higher (chrysotile 64 X 10(6) and tremolite group 540 X 10(6] than in a group of long-term chrysotile miner control subjects who had no asbestos-related disease (chrysotile 23 X 10(6), tremolite group 58 X 10(6], but some patients with mesothelioma had fiber burdens near the mean of the control range. Fiber sizes and aspect ratios in the mesothelioma group were approximately the same as those in the control subjects, and analysis of fiber distribution failed to show any preferential localization in the periphery of the lung. However, the concentration ratio of tremolite in the lungs of the mesothelioma cases compared to the control cases was 9.3, while the ratio of chrysotile was only 2.8. Our findings provide strong evidence that chrysotile mine dust (chrysotile and amphibole components) can produce mesotheliomas in humans; the greater relative amounts of tremolite group amphiboles present in the patients with mesothelioma raise the possibility that these fibers may be important in the pathogenesis of the tumors.
The Quantitative Risks of Mesothelioma and Lung Cancer in Relation to Asbestos exposure
Mortality reports on asbestos exposed cohorts which gave information on exposure levels from which (as a minimum) a cohort average cumulative exposure could be estimated were reviewed. At exposure levels seen in occupational cohorts it is concluded that the exposure specific risk of mesothelioma from the three principal commercial asbestos types is broadly in the ratio 1:100:500 for Chrysostom, ammonites and coprolite respectively. For lung cancer the conclusions are less clear cut. Cohorts exposed only to coprolite or ammonites record similar exposure specific risk levels (around 5% excess lung cancer per f/ml.yr); but Chrysostom exposed cohorts show a less consistent picture, with a clear discrepancy between the mortality experience of a cohort of Chrysostom textile workers in Carolina and the Quebec miners cohort. Taking account of the excess risk recorded by cohorts with mixed fib-re exposures (generally<1%), the Carolina experience looks untypically high. It is suggested that a best estimate lung cancer risk for Chrysostom alone would be 0.1%, with a highest reasonable estimate of 0.5%. The risk differential between Chrysostom and the two amphibious fib-res for lung cancer is thus between 1:10 and 1:50.
Examination of the inter-study dose response relationship for the amphibious fib-res suggests a non-linear relationship for all three cancer endpoints (pleural and peritoneal mesothelioma, and lung cancer). The peritoneal mesothelioma risk is proportional to the square of cumulative exposure, lung cancer risk lies between a linear and square relationship and pleural mesothelioma seems to rise less than linearly with cumulative dose. Although these non-linear relationships provide a best fit of the data, statistical and other uncertainties mean that a linear relationship remains arguable for pleural and lung tumors (but not or peritoneal tumors).
Based on these considerations, and a discussion for the associated uncertainties, a series of quantified risk summary statements for different levels of cumulative exposure are presented.
Examination of the inter-study dose response relationship for the amphibious fib-res suggests a non-linear relationship for all three cancer endpoints (pleural and peritoneal mesothelioma, and lung cancer). The peritoneal mesothelioma risk is proportional to the square of cumulative exposure, lung cancer risk lies between a linear and square relationship and pleural mesothelioma seems to rise less than linearly with cumulative dose. Although these non-linear relationships provide a best fit of the data, statistical and other uncertainties mean that a linear relationship remains arguable for pleural and lung tumors (but not or peritoneal tumors).
Based on these considerations, and a discussion for the associated uncertainties, a series of quantified risk summary statements for different levels of cumulative exposure are presented.
What Mesothelioma Is All About
Mesothelioma is an unusual fatal form of cancer, which actually could be totally avoided. In order to make it a possibility, the government would need to step in and establish regulations requiring the material that causes it, to be totally removed from our society.
Furthermore,, while the removal process was going on, there would need to be a highly publicized educational program developed that explained to the general public, what items they should avoid completely. Essentially, mesothelioma cancer can only be contracted one way, which is from coming in contact with a substance called asbestos.
Asbestos has been used by mankind for thousands of years now. Even when it was used in ancient societies that possessed little or no science at all, they thought there was something wrong with it. Since then, they learned that the people who came in contact with it often would have breathing problems, and would die before their time.
In the middle of the 1800's, the first mining operations for asbestos started in the United States. Little by little, as years passed, it started to become extremely popular, and was used as a raw material to make almost every kind of product imaginable.
Some of the items it was used in were clothes, children's toys, and all kinds of construction materials. The reason it become so widely used, was that it was very expensive to produce, and it possessed many wonderful features. In fact, if not that it causes Mesothelioma Cancer, it would been of tremendous benefit to society.
At the peak of its use, it was largely marketed as almost some kind of gift from god to the people living on Earth. The firms doing the advertising for it were also the companies that were supplying the material to the various manufacturers. Of course, these companies were also making a ton of money in the process.
Only many years after it was scientifically proven to cause Mesothelioma Cancer, did the general public find out the real truth that these companies had been hiding for so long. What was exposed, is that the firms making all of the money off of it and promoting it so extensively, had medical studies dating back to the 1930's that revealed it was harmful to humans.
This information only became public, after several attorneys started suing these companies and forcing them to disclose this once private company research data. Mesothelioma cancer is extremely deadly, and there is very little that can be done for the patient if it is not diagnosed before it has reached stage III in its developmental process.
Now that you know what is mesothelioma cancer, you should surely understand that you never want to come in contact with asbestos. It is so deadly, that even breathing in the air that has a few particles of it can start the cancer growing in your body. Thankfully, today there is very little of it around anymore, but it is still frequently found in old buildings that were constructed during the 20th century.
Furthermore,, while the removal process was going on, there would need to be a highly publicized educational program developed that explained to the general public, what items they should avoid completely. Essentially, mesothelioma cancer can only be contracted one way, which is from coming in contact with a substance called asbestos.
Asbestos has been used by mankind for thousands of years now. Even when it was used in ancient societies that possessed little or no science at all, they thought there was something wrong with it. Since then, they learned that the people who came in contact with it often would have breathing problems, and would die before their time.
In the middle of the 1800's, the first mining operations for asbestos started in the United States. Little by little, as years passed, it started to become extremely popular, and was used as a raw material to make almost every kind of product imaginable.
Some of the items it was used in were clothes, children's toys, and all kinds of construction materials. The reason it become so widely used, was that it was very expensive to produce, and it possessed many wonderful features. In fact, if not that it causes Mesothelioma Cancer, it would been of tremendous benefit to society.
At the peak of its use, it was largely marketed as almost some kind of gift from god to the people living on Earth. The firms doing the advertising for it were also the companies that were supplying the material to the various manufacturers. Of course, these companies were also making a ton of money in the process.
Only many years after it was scientifically proven to cause Mesothelioma Cancer, did the general public find out the real truth that these companies had been hiding for so long. What was exposed, is that the firms making all of the money off of it and promoting it so extensively, had medical studies dating back to the 1930's that revealed it was harmful to humans.
This information only became public, after several attorneys started suing these companies and forcing them to disclose this once private company research data. Mesothelioma cancer is extremely deadly, and there is very little that can be done for the patient if it is not diagnosed before it has reached stage III in its developmental process.
Now that you know what is mesothelioma cancer, you should surely understand that you never want to come in contact with asbestos. It is so deadly, that even breathing in the air that has a few particles of it can start the cancer growing in your body. Thankfully, today there is very little of it around anymore, but it is still frequently found in old buildings that were constructed during the 20th century.
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