The New England journal of medicine
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Comparative Study
Use of the automatic external defibrillator in the management of out-of-hospital cardiac arrest.
The automatic external defibrillator is a simple device that can be used by nonprofessional rescuers to treat cardiac arrest. In 1287 consecutive patients with out-of-hospital cardiac arrest, we assessed the results of initial treatment with this device by firefighters who arrived first at the scene, as compared with the results of standard defibrillation administered by paramedics who arrived slightly after the firefighters. ⋯ In a multivariate analysis of characteristics that influenced survival after ventricular fibrillation, a better survival rate was related to a witnessed collapse (odds ratio, 3.9; 95 percent confidence interval, 2.0 to 7.6), younger age (odds ratio, 1.2; 95 percent confidence interval, 1.0 to 1.4), the presence of "coarse" (higher-amplitude) fibrillation (odds ratio, 4.2; 95 percent confidence interval, 1.6 to 11.0), a shorter response time for paramedics (odds ratio, 1.4; 95 percent confidence interval, 1.0 to 2.1), and initial treatment by firefighters using an automatic external defibrillator (odds ratio, 1.8; 95 percent confidence interval, 1.1 to 2.9). These findings support the widespread use of the automatic external defibrillator as an important part of the treatment of out-of-hospital cardiac arrest, although the overall impact of the use of this device on community survival rates is still uncertain.
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We studied alcohol use before the onset of a first seizure in 308 patients with seizures and 294 controls. The risk of seizures increased with increasing current alcohol use. For unprovoked seizures (i.e., seizures occurring without an antecedent event, such as a recent stroke), the adjusted odds ratios rose from 3-fold at intakes of 51 to 100 g of ethanol per day (95 percent confidence limits, 1.3 and 6.3), to 8-fold at 101 to 200 g per day (95 percent confidence limits, 3.3 and 18.7), and to almost 20-fold at 201 to 300 g per day (95 percent confidence limits, 6.1 and 6.2). ⋯ Among ex-drinkers (abstention greater than or equal to 1 year), no increased risk was detected. Alcohol withdrawal was not associated with the onset of seizures in this study; 16 percent of first seizures in drinkers fell outside the conventionally defined withdrawal period, and the remainder exhibited a seemingly random timing after the last drink. We conclude that the relation of seizures to alcohol use is dose dependent and appears to be causal, and that seizures can be interpreted as a disorder induced by the ingestion of alcohol, independently of alcohol withdrawal.
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Because most colorectal carcinomas appear to arise from adenomas, studies of different stages of colorectal neoplasia may shed light on the genetic alterations involved in tumor progression. We looked for four genetic alterations (ras-gene mutations and allelic deletions of chromosomes 5, 17, and 18) in 172 colorectal-tumor specimens representing various stages of neoplastic development. The specimens consisted of 40 predominantly early-stage adenomas from 7 patients with familial adenomatous polyposis, 40 adenomas (19 without associated foci of carcinoma and 21 with such foci) from 33 patients without familial polyposis, and 92 carcinomas resected from 89 patients. ⋯ Chromosome 17p sequences were usually lost only in carcinomas (75 percent). The four molecular alterations accumulated in a fashion that paralleled the clinical progression of tumors. These results are consistent with a model of colorectal tumorigenesis in which the steps required for the development of cancer often involve the mutational activation of an oncogene coupled with the loss of several genes that normally suppress tumorigenesis.
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Comparative Study
Difference between endothelium-dependent relaxation in arterial and in venous coronary bypass grafts.
Both the internal mammary artery and the saphenous vein are used to construct coronary-artery bypass grafts. We hypothesized that the release or production of endothelium-derived relaxing factor, which regulates blood flow and inhibits platelet function, may differ in venous and arterial grafts. We therefore studied endothelium-dependent relaxation in internal mammary arteries, internal mammary veins, and saphenous veins obtained from 58 patients undergoing coronary bypass surgery. ⋯ Endothelium-independent relaxation in response to sodium nitroprusside was similar in arteries and veins. We conclude that endothelium-dependent relaxation is greater in the mammary artery than in the saphenous vein. The possibility that this contributes to the higher patency rate among arterial grafts than among venous grafts will require further study.