Mechanisms of heavy-metal toxicity. Heavy metals, such asflead, mercury, and uranium, whether radioactive or not, tend to be toxicfand provide industrial hazards during their handling. However, the toficity of each of these substances differs somewhat and may have several facets. A full understanding of this problem requires knowledge ofthe reaftions of these materials with the vital materials of the cells and the rpgsult- ant upsets of functions at the cellular level. A series of studies are being performed at the University Rochester Atomic Energy Project on toxicity effects in micro-org and organs such as the diaphragm and intestines of higher animals ‘utilization. Glucose utilization was completely inhibited withinla few minutes in the presence of certain dilute concentrations of merc However, using a sensitive histochemical method at that tile, no inhibition. (End of UNCLASSIFIED section.) Radiation Instruments Program Film badge calibration a. At the requdst of the Radiation Instruments Branch, the National Bureau of Standards has recently completed a study of the various film dosimeters used wjthin the AEC. ‘This study was divided into two parts. First, a laborator¥ study was made of the minimum range, quality dependence of the dosimet@rs, and second, a cross calibration consisting of an evaluation of the agility of the site to determine doses that were applied to the dosimetefs by the National Bureau of Standards. The cross calibration data coflected by NBS is now being analyzed by the Instruments Branch. It has been suggested, in view of differences reported Canadians and Knolls Laboratory of dosages received by United $ sonnel who worked in Canada on the reactor clean-up, that an inv be extended to the Canadians to participate in a similar cross tion study. Word has been received from Canada that they would to participate in the study, and it is expected that this work completed during January. (End of section for OFFICIAL USE ONL Civil Defense Activities (UNCLASSIFIED) Emergency radiation monitoring program. Recently, revifion was approved in the directive governing the 18 emergency radiation ; L : Cee ee ee oe ats . ridé. mercury could be detected in the diaphragm muscle cells. A few h@urs later, as the mercury appeared within the cells, the respiration fecame progressively depressed. Thus, it appears that the mercury-sensifive reactions involved in glucose utilization are at the cell surfacefiand are concerned with the passage of sugar from the outside to the cll interior. The mercury-sensitive respiratory reactions, however, ockur within the cell, and this imposes a time lag before appearance of th : i

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