Beta Decay of Molecular Tritium.

The beta decay of tritium in the form of molecular T_{2} is the basis of sensitive experiments to measure neutrino mass. The final-state electronic, vibrational, and rotational excitations modify the beta spectrum significantly and are obtained from theory. We report measurements of the branching ratios to specific ionization states for the isotopolog HT. Two earlier, concordant measurements gave branching ratios of HT to the bound HHe^{+} ion of 89.5% and 93.2%, in sharp disagreement with the theoretical prediction of 55%-57%, raising concerns about the theory's reliability in neutrino mass experiments. Our result, 56.5(6)%, is compatible with the theoretical expectation and disagrees strongly with the previous measurements.

Nonalcoholic fatty liver disease: defining a common problem.

Non Alcoholic Fatty Liver Disease (NAFLD), with prevalence of 10-51% in general population involving all ages, is the major cause of elevation of ALT and a common finding by ultrasound screening and may range from simple steatosis, to Non Alcoholic Steatohepatitis (NASH) and its clinical consequences as cirrhosis and hepatocellular carcinoma. In this review will be analyse factors influencing the onset of the disease. NAFLD, primarly associated with insulin resistance, is in fact considered the hepatic manifestation of the metabolic syndrome: a cluster of disorder that includes obesity, diabetes mellitus, dyslipidaemia, arteriosclerosis and hypertension. The increased incidence and prevalence of obesity and diabetes may explain growing interest in NAFLD. Racial, ethnic, enviromental and behaviour models are also reviewed.

The natural history and risk factors for progression of non-alcoholic fatty liver disease and steatohepatitis.

Nonalcoholic fatty liver disease (NAFLD) is a condition of increasing incidence in western Countries seldom associated to other diseases of high prevalence in general population (i.e. diabetes and obesity). NAFLD ranges from simple fatty liver to steatohepatitis (NASH), which may lead to cryptogenic cirrhosis and in some cases hepatocellular carcinoma (HCC). Natural history of NAFLD in humans is poorly understood and progression of liver disease seems to be due to interaction between hosting (i.e. genetic, gut flora, insulin resistance) and environmental factors (social and eating behaviours) that should be responsible of increased oxidative stress within hepatocytes. Even if we need non-invasive markers able to describe the progression of liver disease, only meaning of liver biopsy is useful to characterize the stigmata of worsening such as inflammation and fibrosis.

Clinical epidemiology of childhood cancer in Central America and Caribbean countries.

BACKGROUND: Countries with scarce resources have the right to appropriate essential health care but very few reports discuss how this can be achieved. We assessed the survival of a large cohort of pediatric oncological patients to provide hard data on which to base realistic evaluation and planning schemes. PATIENTS AND METHODS: This multicenter retrospective survey covered consecutively diagnosed and treated patients admitted to eight national level hospitals in seven countries in Central America and the Caribbean. The research protocol was discussed extensively, so the data to be collected and the criteria for their evaluation were clearly pre-defined. We analysed 2214 patients diagnosed between 1996 and 1999 with various cancers, classified as hemato-oncological disorders (70%) and solid tumors (30%). RESULTS: Three-year overall survival was 48.4% [standard error (SE) 1.3]. Detailed analysis of acute lymphoblastic leukemia highlighted the wide intercountry variability: 3-year survival was 62.2% (SE 5.3) in Cuba, 74.2% (SE 3.3) in Costa Rica, 61.7% (SE 4.9) in Nicaragua, and lower in the other four countries. CONCLUSIONS: The yield of diagnostic-therapeutic protocols depends largely on the context of care in which they are applied. This paper documents the importance of including epidemiological research in interventions for cooperation in complex health areas such as pediatric oncology.

[Ethiology and pathology of low birth weight infants in our hospital (author's transl)]. / Correlaciones etiopatológicas del recién nacido de bajo peso, en nuestro medio

A retrospective study on 834 newborns of low birth weight, 2,500 grs., or less over a total of 19,869 live newborns during the year 1973 is presented. They are divided into low birth weight compatible with gestational age and low birth weight for gestational age when birth weight is lower than 10th percentile of Lubchenco's chart. Each of these groups is subdivided in three parts: First part refers to coincidence of frequence of different ethiologic factors or causes of low birth weight (maternal, gestational, placental and termination of pregnancy). The second part has its object in the clinical appraisal of the state at birth of these low birth weight newborns (fetal-obstetric evaluation of Velasco-Cándano, neonatal Apgar scoring, respiratory evaluation by Silvermann-Andersen and evaluation of external maturaty according to Usher). Third part of the study relates the morbility-mortality rate, need for admission, presence of congenital anomalies and autopsy findings in each of these groups of low birth weight newborns. Relation among all these estimated parameters is made presenting some conclusions reached.