The study of the relationship between childhood leukemia and electric power line configurations in the greater Denver, Colorado, area by Wertheimer and Leeper (Am J Epidemiol 109:273-284, 1979) was repeated in Rhode Island, focusing on leukemia (age at onset, 0-20 years; year of onset, 1964-1978). The addresses of 119 leukemia patients and 240 controls were studied by mapping power lines within 50 yards (45.72 m) of each residence. The shortest distance between each power line and the point of the residence closest to it was found; the number and types of wires in each power line were noted. Exposure weights were assigned each type of wire using Wertheimer and Leeper's median field strength reading for each. Assuming that the strength of the field decreases with the square of the distance from its source, and that fields generated by different wires grouped in the same power line are simply additive, a summary value of relative exposure was calculated for each address. Quartile exposure values for controls were used to group patient exposures. Contrary to Wertheimer and Leeper's results, no relationship was found between leukemia and electric power line configurations.
In 1971, Cancer and Leukemia Group B (CALGB) mounted a study of acute lymphocytic leukemia (ALL) that compared the effects of the two steroid hormones dexamethasone and prednisone. Six-hundred-forty-six children and adolescents with ALL were randomized to receive either prednisone or dexamethasone as part of their remission induction therapy. The 493 evaluable patients who achieved complete remission received the same steroid as pulses throughout remission. Specific central nervous system (CNS) therapy was randomized to either six injections of intrathecal methotrexate (IT MTX) alone or to six injections of IT MTX with cranial radiation (2,400 cGy). Both cranial radiation and dexamethasone offered increased protection against CNS relapse as the first site of failure over IT MTX alone. There were 30 CNS relapses among 238 patients (12.6%) receiving cranial radiation plus IT MTX, whereas there were 70 CNS relapses among 225 (P less than 0.001) (22.5%) in those who received IT MTX alone. Similarly, there were 33 CNS relapses among 231 (14.3%) children treated with dexamethasone, whereas there were 67 CNS relapses among 262 (25.6%) treated with prednisone (P = 0.017). Both steroids appeared equal in protecting the bone marrow. Recent national studies have shown significant improvements in preventing CNS relapse over the results in the present report. However, this finding warrants further investigation and, with further documentation, could lead to the substitution of prednisone by dexamethasone to aid further in preventing CNS relapse. This may be particularly important in patients at higher risk for CNS relapse.
This is the seventh reported case of Chagas disease transmission by blood transfusion in the United States and Canada. Although this would not be expected to occur in New England, it did, and this case demonstrates the significance of the immune status of patients as it relates to transfusion-acquired infections, the impact of geographic mobility in disease transmission, and the need for a licensed screening test for Chagas disease for the US blood supply.
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