Leukemia clusters around nuclear facilities in Britain

He bas been retained for the defense by British Nuclear Fuelsplc in two suits in which leukemia and non-Hodgkin's lymphoma have been alleged to result from radiation exposures due to the operation of the nuclear reprocessing plant at Sellafield. This paper has been sent to the senior authors of the papers reporting clusters of leukemia or other malignancy in the vicinity of nuclear facilities in Britain and their comments invited. Subject to considerations of space and CCC style, these comments will be published as submited.     

A mutation in codon 717 of the CHO-K1 elongation factor 2 gene prevents the first step in the biosynthesis of diphthamide

The histidine residue at position 715 of elongation factor 2 (EF-2) is posttranslationally modified in a series of enzymatic reactions to 2-[3-carboxyamido-3-(trimethylammonio)-propyl]histidine, which has been given the trivial name diphthamide. The diphthamide residue of EF-2 is the target site for ADP ribosylation by diphtheria toxin and Pseudomonas exotoxin A. ADP-ribosylated EF-2 does not function in protein synthesis. EF-2 that has not been posttranslationally modified at histidine 715 is resistant to ADP ribosylation by these toxins. In this report we show that a G-to-A transition in the first position of codon 717 of the EF-2 gene results in substitution of arginine for glycine and prevents addition of the side chain of diphthamide to histidine 715 of EF-2. EF-2 produced by the mutant gene is fully functional in protein synthesis.This work was supported by Public Health Service grant AI-09100 from the National Institute of Allergy and Infectious Diseases and by Biomedical Research Support Grant PHS07RR05429-27. Brian Foley is supported by a Cancer Biology Training Grant T32Ca-09286 from the National Cancer Institute.     

Visual function in Huntington's disease patients and presymptomatic gene carriers.

Disturbances of visual cognition, visuomotor performance, and visual memory have been described frequently in Huntington's disease (HD). Early stage visual abnormalities could contribute to these deficits. We evaluated visual processing in 20 control subjects who were non-gene carriers at risk for HD, nine presymptomatic gene-positive subjects, and eight subjects with a recent diagnosis of Huntington's disease. Visual perceptual tests of contrast sensitivity and motion discrimination were used to probe early stage visual processing. Extraocular movements were evaluated in a neurologic examination, and the Digit Symbol test was used to test visual motor performance. Contrast sensitivity did not differ among the three groups. Motion discrimination was impaired in HD subjects but not in the presymptomatic gene carriers when compared to gene noncarriers. Among gene carriers, impaired motion discrimination performance was associated with poorer Digit Symbol performance and extraocular abnormalities. These findings suggest that the early stages of HD are associated with disturbances of motion perception as well as disruptions of visual motor and ocular motor performance.     

Comparison of stress-only vs. stress/rest with technetium-99m methoxyisobutylisonitrile myocardial perfusion imaging

Unlike conventional thallium-201 myocardial imaging, technetium-99m methoxyisobutylisonitrile (MIBI) requires separate stress and rest injections. We prospectively studied 148 consecutive patients referred for myocardial perfusion studies to determine the diagnostic value of rest images once normal exercise or dipyridamole tomographic images had been obtained. In patients referred with no history of previous myocardial infarction in whom the diagnosis of coronary artery disease was suspected, 45 of 109 (41%) patients had normal stress tomographic images. Obtaining rest images did not alter the final interpretation in any of these cases. From this we infer that in patients with normal images after exercise or dipyridamole administration and no past history of myocardial infarction, ^99mTc-MIBI rest images are not required. This provides several advantages including increased speed of diagnosis, decreased patient radiation exposure, improved cost efficiency and decreased demand on tomographic camera time. Offprint requests to: A.Y. Fung     

Gender differences in young adults' beliefs about sunscreen use.

This study employs focus group methodology to explore gender differences in sunscreen use. Guided by the theory of reasoned action, males and females were found to differ on each of the following constructs: behavior, behavioral beliefs, and normative beliefs. Males and females differed in their sunscreen use, with females adopting a more preventive style of sunscreen use and males a more reactive style. Males and females differed in their salient beliefs that motivated their sunscreen use, many of which were related to traditional American gender roles. In addition, although males and females were aware of both positive and negative sources of normative beliefs regarding sunscreen use, females received more encouragement from their mothers and peers than males. Findings are discussed in terms of their implications for the design of future interventions.