98%
921
2 minutes
20
Background: The aim of this study was to develop a mathematical model of the hypothalamo-pituitary-gonadal axis that would reflect available data in humans.
Methods: A model of hormonal relationships at the early follicular and midluteal phases of the human menstrual cycle is proposed.
Findings: Two distinct temporal patterns of oscillatory behavior have been demonstrated for both pituitary and gonadal steroids in the early follicular phase: first, rapid oscillations in gonadotropin releasing hormone, follicle stimulating hormone and luteinizing hormone (Q approximate to 1 hour) that were an immediate consequence of the programmed equations. Second, there were slower, undulating, emergent rhythms in luteinizing hormone and follicle stimulating hormone, and also in estrogen, having oscillatory periods of 2-12 hours. There was also a longer-period (Q2-3 days) emergent rhythm in progesterone. In the mid-luteal phase, estrogen and progesterone rhythms were correlated, and all hormones showed an approximately 6-hour periodicity.
Conclusions: To our knowledge, the oscillatory behavior of peripheral sex steroids in the follicular phase has not been previously noted.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1017/s1092852900019246 | DOI Listing |
BMC Nurs
September 2025
Institute for Public Health and Nursing Research, Department Evaluation and Implementation Research in Nursing Science, University of Bremen, Grazer Straße 4, D- 28359, Bremen, Germany.
Background: School nursing is a complex clinical specialty practice that varies across different countries. Theories, models and frameworks can inform nursing practice. This scoping review aims to explore the conceptualisation and operationalisation of school nursing in theories, models and frameworks.
View Article and Find Full Text PDFJ Math Biol
September 2025
Department of Mathematics, Texas A&M University, Mailstop 3368, College Station, TX, 77843-3368, United States.
We study how environmental stochasticity influences the long-term population size in certain one- and two-species models. The difficulty is that even when one can prove that there is coexistence, it is usually impossible to say anything about the invariant probability measure which describes the coexisting species. We are able to circumvent this problem for some important ecological models by noticing that the per-capita growth rates at stationarity are zero, something which can sometimes yield information about the invariant probability measure.
View Article and Find Full Text PDFPharm Res
September 2025
Mechanical and Aerospace Engineering Department, University of Texas at Arlington, 500 W First St, Rm 211, Arlington, TX, 76019, USA.
Objective: A fundamental understanding of drug diffusion and binding processes is critical for the design and optimization of a wide variety of drug delivery devices. Most of the past literature assume binding to occur uniformly throughout the tissue, or, at best, in specific layers of a multilayer tissue. However, in many realistic scenarios, such as in cancer-targeting drugs, drug binding occurs in discrete irregularly shaped regions.
View Article and Find Full Text PDFJ Math Biol
September 2025
School of Mathematical Sciences and Institute of Natural Sciences, MOE-LSC, CMA-Shanghai, Shanghai Jiao Tong University, Shanghai, China.
It has been noticed that when the waiting time distribution exhibits a transition from an intermediate time power-law decay to a long-time exponential decay in the continuous time random walk model, a transition from anomalous diffusion to normal diffusion can be observed at the population level. However, the mechanism behind the transition of waiting time distribution is rarely studied. In this paper, we provide one possible mechanism to explain the origin of such a transition.
View Article and Find Full Text PDFRen Fail
December 2025
Department of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, China.
This study aimed to develop a predictive model and construct a graded nomogram to estimate the risk of severe acute kidney injury (AKI) in patients without preexisting kidney dysfunction undergoing liver transplantation (LT). Patients undergoing LT between January 2022 and June 2023 were prospectively screened. Severe AKI was defined as Kidney Disease: Improving Global Outcomes stage 3.
View Article and Find Full Text PDF