Hypohidrotic ectodermal dysplasia in females

The authors report a female with full-blown hypohidrotic ectodermal dysplasia and survey the literature concerning cases of the complete syndrome in females. The condition is ordinarily inherited as an X-linked recessive trait but evidence suggests that other patterns of inheritance may occur. There are several examples of probable autosomal recessive inheritance. The syndrome appears to be an example of genetic heterogeneity.This study was made possible in part by U.S.P.H.S. Program Grant in Oral Pathology, DE-1770.     

Elementary school absenteeism and air pollution

This study assessed the association between ambient air pollution and daily elementary school absenteeism in Washoe County, NV, between 1996 and 1998. All 57 elementary schools in Washoe County in northern Nevada were included in the data set. There was a total of 27,793 student enrollments during this study period. The daily average absence rate was 5.09% (+/-1.54%). Air pollutant values including PM(10), O(3), and CO were obtained from seven air monitoring stations. Weather variables were collected from five of seven stations and from the Western Regional Climate Center. The daily average concentrations of PM(10), CO, and O(3) were 32.44 microg/m(3), 2.73 ppm, and 37.45 ppb, respectively. Student absenteeism was regressed on the three air pollutants, weather variables, and other confounding factors, using autoregression analysis. After adjusting for the effects of weather variables, day of the week, month, and holiday indicators, and time trend, we found that CO and O(3) were statistically significant predictors of daily absenteeism in elementary schools. For every 1.0 ppm and 50 ppb increase in CO and O(3), the absence rate would increase 3.79% (95% CI 1.04-6.55%) and 13.01% (95% CI 3.41-22.61%), respectively. However, PM(10) values were negatively correlated with school absenteeism.     

Coronary thrombosis in myocardial infarction: Report of a workshop on the role of coronary thrombosis in the pathogenesis of acute myocardial infarction

In recent years the widely held concept that coronary thrombi cause myocardial infarcts has been seriously questioned. On the basis of pathologic studies, several reports have suggested that coronary thrombi do not cause infarcts but instead are the result of infarction. Should these findings become generally substantiated, the antithrombotic approach to the prevention and therapy of ischemic heart disease must be revised. This workshop was organized to examine more closely this issue and to sort out reasons for such divergent views of the role of thrombosis in the pathogenesis of myocardial infarction.     

The dose-response relationship for ultraviolet-light-induced mutations at the hypoxanthine-guanine phosphoribosyltransferase locus in Chinese hamster ovary cells

Exposure of Chinese hamster ovary (CHO) cells clone K ₁BE₄ to ultraviolet (UV) light at doses up to 86 ergs/mm² did not significantly reduce cell survival, but UV doses of 86–648 ergs/mm² produced an exponential cell killing. Observed mutation frequency to 6-thioguannine resistance induced by UV increases approximately in proportion to increasing doses up to 260 ergs/mm² in a range of 5–648 ergs/mm² examined. The pooled data of mutation frequency f(X) as a function of dose X from 0–260 ergs/mm² is adequately described by f(X)=10^?6 (13.6+2.04 X). That the UVinduced mutations to 6-thioguanine resistance affects the hypoxanthineguanine phosphoribosyltransferase (HGPRT) locus is supported by the observation that all randomly isolated drugresistant colonies contained highly reduced or undetectable HGPRT activity.     

Comparison of radial forearm with fibula and scapula osteocutaneous free flaps for oromandibular reconstruction

OBJECTIVE: To compare our experience with the osteocutaneous radial forearm free flap (group 1) (n = 108) with other commonly used osteocutaneous free flaps (group 2) (n = 56) such as the fibula and scapula in single-stage oromandibular reconstruction. DESIGN: Retrospective case review. SETTING: Tertiary-care academic medical center. PATIENTS: One hundred sixty-three consecutive patients who underwent 164 mandibular reconstructions with osteocutaneous free flaps. MAIN OUTCOME MEASURES: Assessment of preoperative and intraoperative variables for both groups. We compared recipient-site complication rate, intensive care unit stay, total hospital stay, and postoperative function. RESULTS: The most common donor site used was the radius (n = 108 [66%]), followed by the fibula (n = 36 [22%]) and scapula (n = 20 [12%]). Mean follow-up was 29 months (range, 1-116 months). Group 2 patients had larger soft tissue and/or bony defects. Surgical and medical complication rates and major donor site morbidity in group 1 were similar or better when compared with those in group 2. The lengths of the intensive care unit (4 vs 7 days; P = .009) and hospital stays (13 vs 15 days; P = .06) were shorter in group 1. Although the microvascular success rate was similar in both groups, the local wound complication rate was significantly better for group 1. The difference for the length of intensive care unit stay was statistically significant and potentially amounts to more than 6000 dollars of savings. Functional outcomes, including the ability to tolerate oral diet, tracheostomy presence, and dental rehabilitation, were similar between the groups. CONCLUSIONS: The primary site long-term morbidity, donor site morbidity, and postoperative function of osteocutaneous radial forearm free flaps are comparable to those of other commonly used osteocutaneous free flaps such as the fibula and scapula when used in single-stage oromandibular reconstruction.