[Variations in fetal death with regard to the months of the year].
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Female↗
Biomedical subjects
J A Theune
Publications and source records attributed to J A Theune.
Bias in counting procedures for white blood cells.
To increase the precision of low white blood counts with traditional counting procedures often an initial count is performed in 0.1 cu. mm. Only if this pilot count is low, additional zones of 0.1 cu. mm. are counted and the results of the pilot count and the additional count then averaged. This counting procedure should be avoided as it gives biased estimates of the white blood count. The bias is avoided if the result of the initial count is discarded and an independent count is performed in a larger volume. In analogous counting situation-such as radioactivity counts - bias can arise and be prevented in analogous ways.
Diagnostic Errors↗
Determining reference ('normal') limits in medicine: an application.
We provide an account of a study to assess reference limits for eight routine laboratory determinations at the Academic Hospital of the Free University, Amsterdam and emphasize methodological issues rather than results. We argue that reference limits have use mainly in the first phase of the diagnostic process. Reference and target populations should be grossly comparable, and therefore patients (after slight selection) could well serve as references. However, we found major differences between in- and out-patients, so we suggest that this factor, together with age and sex, be taken into account. To arrive at reliable limits, the size of the reference sample should be at least 100. Laboratory reports should provide percentiles, which enable a more flexible decision than do fixed limits.
Adult↗
Seasonality of anencephalic births and pre-ovulatory overripeness ovopathy.
The total number of births and the anencephaly incidence rate in the Netherlands, in the years 1951 to 1968 (both corrected to estimate the 'conception' curves), were analyzed to find their circannual fluctuations and to see whether there was a relation between the two. The results indicate that, as predicted by the seasonal preovulatory overripeness ovopathy (SPOO-) hypothesis, anencephalics are born disproportionately more often than expected during the peak months and less often during the troughs of the total birth curve. Overripeness ovopathy as a teratogenic factor, therefore, may offer a unifying aetiological concept which can also explain other epidemiological findings concerning congenital CNS-defects. This concept may challenge the genetic theories of their causation, and offer new possibilities for 'primary' prevention.
Anencephaly↗