scholarly journals A mathematical model which examines age-related stochastic fluctuations in DNA maintenance methylation

2021 ◽  
pp. 111623
Author(s):  
Loukas Zagkos ◽  
Jason Roberts ◽  
Mark Mc Auley
Keyword(s):  
Mathematical Model ◽  
Stochastic Fluctuations ◽  
Age Related ◽  
Dna Maintenance ◽  
Maintenance Methylation

scholarly journals Malaria prevalence amongst Brazilian Indians assessed by a new mathematical model

1993 ◽  
Vol 111 (3) ◽  
pp. 525-538 ◽  
Author(s):  
M. N. Burattini ◽  
E. Massad ◽  
F. A. B. Coutinho ◽  
R. G. Baruzzi
Keyword(s):  
Mathematical Model ◽  
Control Strategies ◽  
Age Distribution ◽  
Malaria Prevalence ◽  
Reproductive Rate ◽  
Force Of Infection ◽  
Age Related ◽  
Serological Data

SummaryAn alternative way to estimate the endemic level of malaria amongst Brazilian indians is proposed. This is achieved by estimating the age-related “force of infection’ of malaria (the effective inoculation rate), applying a mathematical model, described elsewhere, to serological data. In addition we present a way to estimate the Basic Reproductive Rate of malaria in the same area. The results have shown a good degree of accuracy in describing the endemic pattern of malaria in the area, and also indicate some relevant aspects of its age distribution related to the design of control strategies.

scholarly journals A Novel Method for Detection and Progress Assessment of Visual Distortion Caused by Macular Disorder: A Central Serous Chorioretinopathy (CSR) Case Study

Vision ◽  
2019 ◽  
Vol 3 (4) ◽  
pp. 68 ◽  
Author(s):  
Navid Mohaghegh ◽  
Sebastian Magierowski ◽  
Ebrahim Ghafar-Zadeh
Keyword(s):  
Mathematical Model ◽  
Central Serous Chorioretinopathy ◽  
Home Monitoring ◽  
Age Related Macular Degeneration ◽  
Test Results ◽  
Monitoring Method ◽  
Accurate Detection ◽  
Age Related ◽  
Novel Method

This paper presents a new mathematical model along with a measurement platform for accurate detection and monitoring of various visual distortions (VD) caused by macular disorders such as central serous chorioretinopathy (CSR) and age-related macular degeneration (AMD). This platform projects a series of graphical patterns on the patient’s retina and calculates the severity of VDs accordingly. The accuracy of this technique relies on the accurate detection of distorted lines by the patient. We also propose a simple mathematical model to evaluate the VD created by CSR. The model is used as a control for the test results achieved from the proposed platform. The proposed platform consists of the required hardware and software for the generation and projection of patterns along with the collection and processing of patients against their standard optical coherence tomography (OCT) images. Based on these results, the OCT images agree with the VD test results, and the proposed platform can be used as an alternative home monitoring method for various macular disorders.

scholarly journals Modelizing Drosophila melanogaster longevity curves using a new discontinuous 2-Phases of Aging model

2015 ◽  
Author(s):  
Hervé Tricoire ◽  
Michael Rera
Keyword(s):  
Mathematical Model ◽  
Energy Homeostasis ◽  
Continuous Process ◽  
Biological Significance ◽  
Food Dye ◽  
Age Related ◽  
Wide Range ◽  
Resistance To Stress ◽  
Molecular Phenotypes ◽  
Single Constant

Aging is commonly described as being a continuous process affecting progressively organisms as time passes. This process results in a progressive decrease in individuals fitness through a wide range of both organismal – decreased motor activity, fertility, resistance to stress – and molecular phenotypes – decreased protein and energy homeostasis, impairment of insulin signaling. In the past 20 years, numerous genes have been identified as playing a major role in the aging process, yet little is known about the events leading to that loss of fitness. We recently described an event characterized by a dramatic increase of intestinal permeability to a blue food dye in aging flies committed to die within a few days. Importantly, flies showing this so called ‘Smurf’ phenotype are the only ones, among a population, to show various age-related changes and exhibit a high-risk of impending death whatever their chronological age. Thus, these observations suggest that instead of being one continuous phenomenon, aging may be a discontinuous process well described by at least two distinguishable phases. In this paper we addressed this hypothesis by implementing a new 2-Phases of Aging mathematiCal model (2PAC model) to simulate longevity curves based on the simple hypothesis of two consecutive phases of lifetime presenting different properties. We first present a unique equation for each phase and discuss the biological significance of the 3 associated parameters. Then we evaluate the influence of each parameter on the shape of survival curves. Overall, this new mathematical model, based on simple biological observations, is able to reproduce many experimental longevity curves, supporting the existence of 2-phases of aging exhibiting specific properties and separated by a dramatic transition that remains to be characterized. Moreover, it indicates that Smurf survival can be approximated by one single constant parameter for a broad range of genotypes that we have tested under our environmental conditions.

scholarly journals Forecasting early climax on taking into account of reproductive and biological age indicators

2019 ◽  
pp. 23-28
Author(s):  
O.O. Efimenko ◽  
I.M. Retunska ◽  
T.O. Marturosova
Keyword(s):  
Mathematical Model ◽  
Discriminant Analysis ◽  
Subsequent Development ◽  
Risk Groups ◽  
Reproductive Age ◽  
Smoking History ◽  
Biological Aging ◽  
Individual Treatment ◽  
Age Related ◽  
Treatment Measures

A great asset of our time is a significant increase in life expectancy. This is especially true for women’s health issues, as women live longer than men and are more stubbornly opposed to age-related changes and aging, trying to preserve not only beauty and youth, but also reproductive function. The use of algorithms and mathematical models for predicting the occurrence of pathology in medical practice makes it possible to predict in advance not only the fact of the occurrence of this complication, but also to determine the likelihood of its occurrence, which is very important for the subsequent identification of risk groups in order to develop individualized preventive and treatment measures. Namely, the timely appointment of preventive measures and the development of individual treatment programs will improve the quality of life of every woman. The purpose of the work is to develop an algorithm and a mathematical model for predicting the risk of developing early climax (EC) against the background of a woman’s biological aging by studying various factors with the subsequent development of individualized preventive and treatment measures. In order to study the possibilities of predicting the occurrence of RK against the background of a woman’s biological aging, a retrospective analysis of the frequency of the studied factors in patients with EC was carried out in comparison with women with preserved menstrual function and timely onset of menopause. The method of step-by-step discriminant analysis was used as a mathematical model, which made it possible to identify the probability of a difference between the comparison groups by the F value of Fisher statistics, to develop a forecast algorithm and conduct mathematical modeling. 12 out of 145 factors were identified by discriminant analysis, which most influenced the occurrence of this pathology, including the following: early menopause in relatives, smoking, history of artificial abortion (more than 3), extragenital pathology; the presence of stressful situations at home, at work; surgery on the uterus and appendages; inadequate physical and mental activity; adiposity; low serum estradiol concentrations; high levels of follicle-stimulating hormone in serum; anti-Mullerian serum hormone levels below normal and more than three in vitro fertilization attempts. It is the method of multivariate mathematical analysis, considering all the most informative factors and variants of their expression, made it possible to create this prognostic model. The algorithm and mathematical model developed by the authors to predict the occurrence of this pathology, considering certain factors, have a high sensitivity and informativeness, which makes it possible to identify the risk groups of patients of reproductive age in the occurrence of this pathology in order to prevent and prescribe individual treatment in a timely manner.

DNA maintenance methylation enzyme Dnmt1 in satellite cells is essential for muscle regeneration

2021 ◽  
Vol 534 ◽  
pp. 79-85
Author(s):  
Hiroyuki Iio ◽  
Tadahiko Kikugawa ◽  
Yuichiro Sawada ◽  
Hiroshi Sakai ◽  
Shuhei Yoshida ◽  
...  
Keyword(s):  
Satellite Cells ◽  
Muscle Regeneration ◽  
Dna Maintenance ◽  
Maintenance Methylation

scholarly journals Dissecting the precise role of H3K9 methylation in crosstalk with DNA maintenance methylation in mammals

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Qian Zhao ◽  
Jiqin Zhang ◽  
Ruoyu Chen ◽  
Lina Wang ◽  
Bo Li ◽  
...  
Keyword(s):  
H3k9 Methylation ◽  
Dna Maintenance ◽  
Precise Role ◽  
Maintenance Methylation

scholarly journals Revealing Age-Related Changes of Adult Hippocampal Neurogenesis

2017 ◽  
Author(s):  
Frederik Ziebell ◽  
Sascha Dehler ◽  
Ana Martin-Villalba ◽  
Marciniak-Czochra Anna
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Cell Dynamics ◽  
Cellular Changes ◽  
Age Related ◽  
Adult Hippocampus ◽  
Age Related Changes

In the adult hippocampus, neural stem cells (NSCs) continuously produce new neurons that integrate into the neuronal network to modulate learning and memory. The amount and quality of newly generated neurons decline with age, which can be counteracted by increasing intrinsic Wnt activity in NSCs. However, the precise cellular changes underlying this age-related decline or its rescue through Wnt remain unclear. The present study combines development of a mathematical model and experimental data to address features controlling stem cell dynamics. We show that available experimental data fit a model in which quiescent NSCs can either become activated to divide or undergo depletion events, consisting of astrocytic transformation and apoptosis. Additionally, we demonstrate that aged NSCs remain longer in quiescence and have a higher probability to become re-activated versus being depleted. Finally, our model explains that high NSC-Wnt activity leads to longer time in quiescence while augmenting the probability of activation.

scholarly journals A Mathematical Model which Examines Age-Related Stochastic Fluctuations in DNA Maintenance Methylation

2021 ◽  
Author(s):  
Loukas Zagkos ◽  
Jason Roberts ◽  
Mark Mc Auley
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Molecular Level ◽  
Cpg Islands ◽  
Gene Promoter ◽  
Input Noise ◽  
Regulatory Processes ◽  
Stochastic Fluctuations ◽  
Age Related ◽  
The Impact

AbstractDue to its complexity and its ubiquitous nature the ageing process remains an enduring biological puzzle. Many molecular mechanisms and biochemical process have become synonymous with ageing. However, recent findings have pinpointed epigenetics as having a key role in ageing and healthspan. In particular age related changes to DNA methylation offer the possibility of monitoring the trajectory of biological ageing and could even be used to predict the onset of diseases such as cancer, Alzheimer’s disease and cardiovascular disease. At the molecular level emerging evidence strongly suggests the regulatory processes which govern DNA methylation are subject to intracellular stochasticity. It is challenging to fully understand the impact of stochasticity on DNA methylation levels at the molecular level experimentally. An ideal solution is to use mathematical models to capture the essence of the stochasticity and its outcomes. In this paper we present a novel stochastic model which accounts for specific methylation levels within a gene promoter. We quantify the uncertainty of the eventual cite-specific methylation levels for different values of methylation age, depending on the initial methylation levels. Our model predicts the observed bistable levels in CpG islands. In addition, simulations with various levels of noise indicate that uncertainty predominantly spreads through the hypermethylated region of stability, especially for large values of input noise. A key outcome of the model is that CpG islands with intermediate methylation levels tend to be more susceptible to dramatic DNA methylation changes towards both hypomethylation and hypermethylation, due to increasing methylation age.

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