Fall 2010
*Q. In reference to the kinetics of caffeine, I understand the process by which caffeine inhibits the enzyme phosphodiesterase and thereby inhibiting the breakdown of cAMP. How does tolerance fit into this? Why would it take more caffeine over time to have the same effect? Does the GI tract absorb less over time or does the phosphodiesterase lose its affinity for caffeine over time?
A. There is a terrible problem for me and Wally of Dilbert, who had to go to the Betty Ford Center to get off coffee. (He found a Starbucks on the way home from Betty’s place – Oh well.) The body simply makes more phosphodiesterase, so over time, it takes more and more caffeine to get going. When one stops the bean quickly, cold turkey, the excess of phophodiesterase remains for a week or so and makes the body very sluggish. I have a headache for three days and feel awful for another 4 or 5 days. My guess is that the manufacture of phophodiestease takes 15 or 20 enzymes and these require the RNA, etc., from DNA which was switched on by the lack of phophodiesterarase. Once there is enough, a feedback mechanism will shut off the DNA, and the enzymes will eventually dissipate.
Q. Methylmetacrylate is a methyl ester used in the dental industry as a molding pudding. It has been associated with nerve impulse changes when handled without the use of gloves. Yet, I can’t seem to find an MSDS that indicates the types of gloves that should be worn when handling methymetacryalate, they merely state “proper gloves”. How are the medical community to know how to handle these puddys when the chemical supplier is not providing enough detail….does this come down to not wanting to make themselves liable should a suggested glove fail?
A. There are many ways of describing gloves, the material is only one parameter. The thickness is another. Breakthough time is a common parameter, but that is done with a test section, not a whole glove, and certainly not a glove that someone has been wearing for a week. Anyhow, some gloves might be poorly made. The best way would be to specify a manufacturer and model of glove, and that is what I suspect the MSDS authors are avoiding. Perhaps because they don’t know a manufacture who is interested in the testing.
Q. Do Unions address environmental issues for workers? Would steel workers have a legitimate issue to address by asking for long term studies in health defects resulting from MoO3 dust exposure? Would this happen in reality, because while they are bad, these MoO3 symptoms are tame compared to effects from exposure to some industrial chemicals and processes?
A. We go into those issues more in ENVE 649, Hazardous and Toxic Waste Management, where we spend time on worker health and safety directly. OSHA, the Occupational Health and Safety Administration is in charge of workplace health hazards and publishes regulations concerning them. If MoO3 had an OSHA limit, called a PEL, it would set the law regarding exposure. The ACGIH is the standards-setting body of the industrial hygiene profession http://www.acgih.org/home.htm . The ACGIH is not political, but uses its limited resources to address workplace health hazards – generally by collecting and examining scientific data from research and professional studies. ACGIH TLVs and other yardsticks are considered more scientifically correct than the OSHA regulations. MoO3 is not regulated or have a TLV, however “soluble Mo” compounds are regulated, so you would need to go further. Here an MSDS might be useful, if it explains the solubility of MoO3. If it is soluble, it will give the OSHA PEL and or the ACGIH TLV.
Labor unions have Washington DC lobbies that agitate and push for stricter regulation of all workplace chemicals, but they have priorities and will start with the most egregious or politically important chemical. Also, if a chemical is under review by OSHA for whatever reason, the unions will testify about it. They do this using consultants, but these are expensive.