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31.
Cerebral dynamics of N-isopropyl-(123I)p-iodoamphetamine   总被引:1,自引:0,他引:1  
Temporal changes in the distribution of N-isopropyl-(123I)p-iodoamphetamine (IMP) within the brain are measured with serial tomographic imaging. In the cerebellum there is a decrease in activity of 42% from the early [15-45 min postinjection (p.i.)] to the late (210-240 min p.i.) scan, while in the cortex the decrease is 18%, and in the basal ganglia there is no decrease within this time. In brain tumors there was no IMP uptake in the early as well as in the late scans, regardless of tumor type, perfusion rate, or blood-brain barrier dysfunction. In 11 of 43 patients with a cerebral infarction a real increase of 123I activity (mean +21%) was seen in the late images. This "filling in" phenomena might be useful in selecting patients for bypass surgery. In these patients the diaschisis cerebelli, seen in the early scans, disappeared in the late images. The regional distribution of IMP changes with time; spatial ratios might be blurred by temporal changes. High-flow areas such as visio-auditory centers can be delineated clearly after stimulation in fast early scans; in these areas the pharmacokinetics of 123I are different from other cortex regions. To get the full information from the IMP brain uptake, both spatial and temporal variation must be measured.  相似文献   
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Food-related illness and death in the United States.   总被引:62,自引:0,他引:62  
To better quantify the impact of foodborne diseases on health in the United States, we compiled and analyzed information from multiple surveillance systems and other sources. We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Known pathogens account for an estimated 14 million illnesses, 60, 000 hospitalizations, and 1,800 deaths. Three pathogens, Salmonella, Listeria, and Toxoplasma, are responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents account for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths. Overall, foodborne diseases appear to cause more illnesses but fewer deaths than previously estimated.  相似文献   
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Low maternal weight gain during pregnancy has been suggested as a cause of intrauterine growth retardation (IUGR). However, pregnancy weight gain and fetal growth vary greatly throughout pregnancy. We examined the relationship between maternal weight gain in individual trimesters to the risk of IUGR in 10,696 women enrolled in the National Collaborative Perinatal Project (NCPP) and the Child Health and Development Study (CHDS). Low weight gain was defined as <-0.1 kg/wk for the first trimester and <0.3 kg/wk for the second and third trimester. IUGR was defined as a birth weight <2500 g in full-term infants. Low weight gain in the first trimester was not associated with an increased risk of IUGR. After controlling for confounding factors (maternal height, body mass index, parity, race, toxemia, diabetes), low weight gain in the second trimester was associated with a relative risk of IUGR of 1.8 (1.3-2.6) in the NCPP cohort and 2.6 (1.6-4.1) in the CHDS cohort. Similarly, low weight gain in the third trimester was associated with a relative risk of IUGR of 1.7 (1.3-2.3) in the NCPP cohort and 2.5 (1.7-3.8) in the CHDS cohort. After correcting for weight gain in other trimesters, this increased risk remained. Increased risk of IUGR was observed with low second and third trimester weight gain across the spectrum of maternal body mass index. The risk of low weight gain in the second or third trimester was significantly lower in teenagers and significantly greater in overweight women and women aged 35 y or older. Low weight gain in either the second or third trimester was associated with a significantly greater risk of intrauterine growth retardation in two distinct cohorts. We conclude that increased awareness of maternal weight gain in mid and late pregnancy is critical to identifying infants at risk for IUGR.  相似文献   
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CONTEXT: States need data on live births resulting from unintended pregnancies in order to assess the need for family planning services; however, many states do not collect such data. Some states may use extrapolated rates from other states. METHODS: Pregnancy Risk Assessment Monitoring System (PRAMS) data were assessed to explore the feasibility of extrapolating data on the percentage of live births resulting from unintended pregnancies from states that collect these data to states that do not. Data on women who had live births between 1993 and 1995 were examined for eight states: Alabama, Florida, Georgia, Michigan, New York (excluding New York City), Oklahoma, South Carolina and West Virginia. Logistic regression was used to determine state variation in the odds of delivering a live birth resulting from an unintended pregnancy after adjustment for maternal race, marital status, age, education, previous live birth and participation in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). RESULTS: The percentage of live births resulting from unintended pregnancy ranged from 33% in New York to 49% in Alabama, Georgia and South Carolina. Compared with women in Alabama, women in Oklahoma were more likely to deliver a live birth resulting from an unintended pregnancy (odds ratio of 1.2, confidence interval of 1.1-1.3) and women in New York State were less likely (odds ratio of 0.7, confidence interval of 0.6-0.8) to have such a birth. However, unmarried white women in New York had lower odds of having a live birth resulting from an unintended pregnancy and married black women in Michigan had higher odds of having a live birth resulting from unintended pregnancy than their counterparts in Alabama. Although the percentages varied, in all eight states women who were black, were unmarried, were younger than 20 years of age, had less than 12 years of education or had more than one child had higher percentages of live births resulting from unintended pregnancy than women with other demographic characteristics. CONCLUSIONS: Data on which women have the greatest risk of delivering a live birth resulting from an unintended pregnancy may be extrapolated from one state to another, but the rate of such births may overestimate or underestimate the problem from one state to another.  相似文献   
39.
The term ventricular remodeling has been coined to describe the geometrical changes in size and shape of the left ventricle occurring after large myocardial infarcts. We do not exactly know what initiates this process. Slipping of myofilaments following destruction of connective tissue--probably due to metalloproteinase activation--could be the initial event. As a consequence, wall stress is increased triggering deleterious adaptation processes, such as: - intracardiac angiotensin II generation; - cardiac endothelin formation and release; - pro-apoptotic signals for cardiomyocytes; - hypertrophic signals for fibroblasts and cardiomyocytes. This cascade of events is not only observed in the process of remodeling following myocardial infarction but is also operating during the progression of heart failure. Therapeutic principles therefore are similar in both conditions: - reduction of wall stress (pharmacological or mechanical unloading of the heart); - blockade of angiotensin II generation or of AT1-receptors (ACE-inhibitors or AT1 antagonists); - blockade of endothelin receptors (ET(A)-blockers); - blockade of adrenergic receptors (preferably beta1-adrenergic receptor blockers). Better understanding of the molecular mechanisms of the remodeling process already has fueled the search for new therapeutic interventions (such as endothelin receptor blockers, aldosterone antagonists and growth hormone application). Continuous research in this field may be especially rewarding if we will succeed in identifying the very first step in the cascade.  相似文献   
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Heart failure is characterized by increased vascular resistance and water retention. Adrenomedullin is a peptide hormone with vasodilating and diuretic properties whose efficacy in heart failure has not been well established. We used an aortocaval shunt model of moderate heart failure in rats and infused increasing doses of adrenomedullin, both as bolus injections and 20-min infusions. In controls, a clear dose-dependent 4.8+/-1.0 to 13.6+/-2.3 mm Hg decrease in arterial blood pressure was observed after injection of 1 microg to 30 microg of adrenomedullin. In rats with aortocaval shunt, the hypotensive responses were significantly diminished. The urine flow rate, which was diminished at baseline in rats with aortocaval shunt, was increased and normalized by adrenomedullin administration. The glomerular filtration rate increased after infusion of adrenomedullin (0.5 microg/kg min(-1)) from 2.37+/-0.25 to 3.47+/-0.43 ml/min (P<0.01) in controls and from 1.79+/-0.33 to 2.58+/-0.49 (P<0.05) in rats with aortocaval shunt. Similarly, renal blood flow was significantly increased by adrenomedullin in both groups. Our results indicate a beneficial effect of adrenomedullin on renal function in rats with aortocaval shunt. These data suggest that adrenomedullin might be of potential therapeutic value in heart failure, without inordinately decreasing blood pressure.  相似文献   
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