Biomedical subjects

E Seneta

Publications and source records attributed to E Seneta.

4 recordsLinked to original sources

PubMed1992

Temporal coupling among luteinizing hormone, follicle stimulating hormone, beta-endorphin and cortisol pulse episodes in vivo.

We have applied explicit probability equations to assess possible non-random associations among four distinct hormone series consisting of episodic luteinizing hormone, follicle stimulating hormone, beta-endorphin, and/or cortisol pulses observed under physiological conditions in normal men. Closed-form likelihood functions permitted us to demonstrate significantly coordinated patterns of multiple hormone release. A specific quadruple co-pulsatility pattern was observed, in which the two gonadotropic hormones (luteinizing hormone and follicle stimulating hormone) were co-secreted and coupled by a 10-20 min lag to the later release of beta-endorphin. In turn, beta-endorphin release episodes were followed within 0-30 min by cortisol bursts. Conditional probability analysis allowed us to reject with high statistical confidence the null hypothesis that this unique temporally specified pattern of quadruple hormone release was due to purely random associations among the four pulsatile series. We conclude that discrete hormone release episodes associated with four hormones within the gonadotropic and corticotropic axes in man exhibit significantly lagged non-random temporal coupling in vivo.

Adult↗

PubMed1991

Analysis of the copulsatility of anterior pituitary hormones.

We have used combinatorial algebra and computer simulations to calculate expected means, variances, and probabilities of hormone-peak coincidences in 2 or more endocrine pulse series. We illustrate application of this conditional probability analysis to pulsatile LH, FSH, and/or PRL data. We observed that 1) serum LH and FSH pulses in 14 young men were randomly associated on different days (P greater than 0.10), but highly synchronized on any given day (P less than 0.0001); 2) serum LH and FSH (P less than 0.0001), LH and PRL (P = 0.023), and FSH and PRL (P = 0.0003) peaks were significantly coupled in healthy postmenopausal women; and 3) the number of triple coincidences among LH, FSH, and PRL release episodes in postmenopausal women significantly exceeded chance expectations (P less than 0.0001). We conclude that suitable statistical coincidence analysis can offer an informative tool with which to evaluate nonrandom event concordance in endocrine investigations, such as clinical studies of the temporally coordinated release of anterior pituitary hormones.

Adult↗

PubMed1975

Selection equilibria in a multiallele single-locus setting.

The aim of the paper is to clarify and unify various well-known results in the setting mentioned in the title, since some of these results are either inaccurate, or incomplete; or refer to different concepts bearing the same name. Emphasis is given to the general case, i.e. we include the situation of singular fitness matrix, a topic which is generally avoided. We proceed by using a specific generalized inverse of the fitness matrix. A full bibliography is given.

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PubMed1974

A note on the balance between random sampling and population size. (On the 30th anniversary of G. Malécot's paper).

Wright's model for the effects of random fluctuations in gene frequency in a population of fixed size is generalized to randomly fluctuating population size, and treated from the viewpoint of G. Malécot, using a martingale convergence theorem. The gene frequency approaches a limit, whose value depends on the actual realization, or history, of the process; that is, convergence is with probability one (or: almost surely) in statistical language. The limit does not necessarily represent a state of fixation of either allele; in particular, the limiting probability distribution is not necessarily trivial. For the special case of deterministically varying population size, a necessary and sufficient condition for such non-triviality is given.

Alleles↗