CT ratios: parameter estimates are inconsistent with SURUSS publications?
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Down Syndrome↗
Biomedical subjects
Barry Nix
Publications and source records attributed to Barry Nix.
Sonographic screening for trisomy 13 at 11 to 13(+6) weeks of gestation.
OBJECTIVE: The purpose of this study was to examine the sonographic features of trisomy 13 at 11 to 13(+6) weeks of gestation. STUDY DESIGN: This was a retrospective study that examined the features of trisomy 13 at the ultrasound scan at 11 to 13(+6) weeks of gestation, which in our center is performed for the measurement of crown-rump length, nuchal translucency thickness, and fetal heart rate and the examination for major defects. RESULTS: In the 181 fetuses with trisomy 13, there were holoprosencephaly, exomphalos, and/or megacystis in 92 fetuses (50.2%), fetal heart rate above the 95th percentile in 129 fetuses (71.3%), and nuchal translucency above the 95th percentile in 141 fetuses (77.9%). There was no significant association between nuchal translucency and fetal heart rate, and it was estimated that inclusion of fetal heart rate in nuchal translucency screening can improve the detection rate of trisomy 13 by approximately 5%. CONCLUSION: At the 11 to 13(+6)-week scan, the measurement of fetal nuchal translucency and fetal heart rate and fetal examination for holoprosencephaly, exomphalos, and megacystis can identify >90% of fetuses with trisomy 13.
Adult↗
Spatial contouring of risk: a tool for environmental epidemiology.
The possible elevation of disease rates in the proximity of site-specific environmental hazards is much investigated. Single-site studies are subject to problems of reporting bias and statistical power, and multisite studies to heterogeneity of exposure. Both types of studies usually use concentric circular regions centered on a site as a surrogate for defining the exposed and unexposed populations. This approach does not take into account the actual spatial pattern of toxicant dispersion or the spatial pattern associated with the population, and so much useful information is wasted. We report a kernel density technique to map risk contours for disease, which is not influenced by the coordinates of any putative environmental hazard and which could be married to actual spatial exposure patterns.
Cluster Analysis↗
Modeling the hepatitis C virus epidemic in France using the temporal pattern of hepatocellular carcinoma deaths.
Deuffic et al. developed a compartmentalized model that characterized the evolution and spread of the hepatitis C virus (HCV) within France. There were various parameters defining the age- and sex-dependent transition probabilities between chronic hepatitis and cirrhosis in need of determination to completely specify their model. These were estimated by means of a weighted least-squares procedure that was executed numerically. The objective function used was based on the distribution of the age at death from hepatocellular carcinoma (HCC) rather than the temporal pattern of deaths due to HCC from 1979 to 1995. In this report, we investigate the impact of using an objective function based on the temporal pattern of deaths. We show that the dynamics of the epidemic can be quite different, in particular, short-term prediction of HCC deaths by HCV infection and times to death from onset of disease.
Age Factors↗