Masaki Munaka

Analysis and rearrangement of human karyotypes by computer

A system useful for the collection and analysis of a large number of abnormal karyotypes and for studies on the relationship between cytogenetic abnormalities and clinical features of diseases is reported. The program is based on the disintegration and rearrangement of abnormal karyotypes recorded according to the 1978 International System for Human Cytogenetic Nomenclature (ISCN).

Multiplicative effect of hyperpepsinogenemia I and non-secretor status on the risk of duodenal ulcer in siblings.

SummaryIn a search for genetic markers of duodenal ulcer, serum pepsinogen I level, ABO blood groups and secretor status were determined in 89 siblings of 34 duodenal ulcer families. Duodenal ulcer patients were likely either to have hyperpepsinogenemia I or to be non-secretors on a familial basis, but not to have an increased frequency of blood group O. The frequency of duodenal ulcer in the siblings was highest in hyperpepsinogenemia I/non-secretor and lowest in normopepsinogenemia I/secretor. Therefore, the influence of two genes, hyperpepsinogenemia I and non-secretor, on the risk of duodenal ulcer is multiplicative. These results provide evidence on the hypothesis of polygenic inheritance of duodenal ulcer.

Non-invasive automatic determination of anaerobic threshold using double gas exchange parameters

A new technique for determining the anaerobic threshold (AT) in real-time during a progressive exercise test was proposed with special consideration to its safety. We applied the discriminant analysis based on the linear logistic regression model to two groups of gas exchange parameters at times just before and after the lactate (LA) threshold (determined by blood LA kinetics; the external criterion of AT) during the incremental exercise test in 21 young males. As a result, the selected variables for estimating AT accurately (the discriminant rate = 100%), were VE/VO2 and the relative change in VE. Our idea of the new technique for determining AT is based on the probability function (p(x)) derived from the discriminant analysis. At each time at which the gas exchange parameters are acquired during the exercise test, p(x) is calculated, and the decision whether the present exercise level is in the pre, just, or post-AT level is made by the p(x). The technique is able to stop the exercise test as quickly as possible after passing through the AT level. To evaluate the new technique, the data set of 66 females (aged 16-57) was applied as a form of simulation. It was shown that the exercise test could be stopped by the technique at a level of only 0.2-0.5 l/min in VO2 higher than AT. This advantage of the technique makes the exercise test safer for middle-aged or old men, and patients during cardiac rehabilitation.