[New discoveries on oral contraceptives and risk of breast cancer. International data show a moderate increase in risk].
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Breast Neoplasms↗
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Results for “Multiregional Analysis”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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Fertility and mortality indicators.
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Adolescent↗
Migration and settlement: a multiregional comparative study.
"In 1976, the International Institute for Applied Systems Analysis initiated a study of migration and population distribution patterns in its seventeen member nations. In each country, the analysis was carried out by national scholars using techniques of multiregional demography. In this paper the authors describe the organization of the study, discuss the data bases used, evaluate the main results obtained, and review some of the methodological research that has been generated by the study. Among the...conclusions are recommendations for researchers wishing to carry out a multiregional demographic analysis." Consideration is given to national and subnational patterns of mortality, fertility, and migration; age composition; and regional population distribution.
Age Distribution↗
Multiregional gene expression profiling identifies MRPS6 as a possible candidate gene for Parkinson's disease.
Combining large-scale gene expression approaches and bioinformatics may provide insights into the molecular variability of biological processes underlying neurodegeneration. To identify novel candidate genes and mechanisms, we conducted a multiregional gene expression analysis in postmortem brain. Gene arrays were performed utilizing Affymetrix HG U133 Plus 2.0 gene chips. Brain specimens from 21 different brain regions were taken from Parkinson's disease (PD) (n = 22) and normal aged (n = 23) brain donors. The rationale for conducting a multiregional survey of gene expression changes was based on the assumption that if a gene is changed in more than one brain region, it may be a higher probability candidate gene compared to genes that are changed in a single region. Although no gene was significantly changed in all of the 21 brain regions surveyed, we identified 11 candidate genes whose pattern of expression was regulated in at least 18 out of 21 regions. The expression of a gene encoding the mitochondria ribosomal protein S6 (MRPS6) had the highest combined mean fold change and topped the list of regulated genes. The analysis revealed other genes related to apoptosis, cell signaling, and cell cycle that may be of importance to disease pathophysiology. High throughput gene expression is an emerging technology for molecular target discovery in neurological and psychiatric disorders. The top gene reported here is the nuclear encoded MRPS6, a building block of the human mitoribosome of the oxidative phosphorylation system (OXPHOS). Impairments in mitochondrial OXPHOS have been linked to the pathogenesis of PD.
Adult↗
[Stable multiregional population as a tool for economic analysis. An application to Italy, 1977-1986].
"The intensity of short-term fluctuations in a population's demographic behaviour is often overshadowed by a force of inertia resulting from the structures inherited from past behaviour. Stable population theory produces an effective way to eliminate this 'weight of the past'. This article presents the results of an application of this approach in analyzing changes in the fertility, migration and mortality regime of the Italian population during the 1977-1986 period." (SUMMARY IN ENG AND SPA)
Demography↗
Facilitated diffusion and membrane permeation of fatty acid in albumin solutions.
Facilitated transport is characteristic of most living systems, and usually involves a series of consecutive adjacent transfer regions, each having different transport properties. As a first step in the analysis of the multiregional problem, we consider in a single unstirred layer the facilitated diffusion of fatty acid (F) in albumin (A) solution under conditions of slow versus rapid association-dissociation, accounting for differing diffusivities of the albumin-fatty acid complex (AF). Diffusion gradients become established in an unstirred layer between a source of constant concentration of A, AF, and F in equilibrium, and a membrane permeable to F. The posited system does not reduce to a thin- or thick-layer approximation. The transient state is prolonged by slower on/off binding rates and by increasing the thickness of the unstirred layer. Solutions to transient and steady state depend upon the choice of boundary conditions, especially for thin regions. When there are two regions (each with its specific binding protein) separated by a permeable membrane, the steady-state fluxes and concentration profiles depend on the rates of association and dissociation reactions, on the diffusion coefficients, local consumption rates, and on the membrane permeability. Sensitivity analysis reveals the relative importance of these mechanisms.
Biological Transport, Active↗
Caregiving and institutionalization of cognitively impaired older people: utilizing dynamic predictors of change.
PURPOSE: The purpose of this study was to identify reliable predictors of nursing home entry over a 3-year period in a sample of 3,944 persons with dementia who resided in a home setting at baseline. Strengths of the analysis include a multiregional recruitment strategy, incorporation of salient caregiver characteristics, and a 3-year prospective design that allows for the modeling of change in important variables (e.g., care recipient functional status or caregiving indicators) when time to institutionalization is predicted. DESIGN AND METHODS: Data were derived from the control sample of the Medicare Alzheimer's Disease Demonstration Evaluation (MADDE). A Cox proportional hazards model was used to predict time to institutionalization among individuals with dementia (baseline was enrollment into MADDE). Predictors included care recipient demographics, caregiver demographics, and time-varying measurements of care recipient functional status, caregiving indicators, and service utilization. Indicators of change were also incorporated to capitalize on the prospective data available. RESULTS: Although several results were consistent with prior findings, caregiving indicators (i.e., burden and self-rated health) and community-based service use were significant predictors of earlier placement. Change in caregiver instrumental activities of daily living and care recipient activities of daily living were also related to expedited institutionalization. IMPLICATIONS: The findings emphasize the importance of incorporating both care recipient and caregiver function and service use patterns when targeting programs designed to prevent or delay institutionalization for people with dementia.
Adult↗
Analysis of urban-rural population dynamics of China: a multiregional life table approach.
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Age Factors↗
Analysis of noteworthy indicators on the anesthesia record: a prospective, multiregional study.
A national sample of anesthesia records were studied prospectively for the presence or absence of predetermined, noteworthy record indicators judged important in documenting a basic core of information describing the monitoring and care provided in a generic clinical setting. Only records involving the administration of a volatile anesthetic for the purpose of achieving general anesthesia, prepared by providers with at least 6 months of experience in anesthesia care were examined. No identifying patient, provider, or institutional data were recorded. Indicators were scored in a "present/absent" format. All data were pooled; the goal was to describe the overall phenomena in terms of frequency of compliance. A total of 4,989 anesthesia records were evaluated in terms of 13 record indicators. Those missed ranged from 0.0% (patient identification) to 28.6% (notation regarding emergence). Ten were omitted on less than 6% of the records: 3 (surgery and/or anesthesia start time, notation regarding emergence, surgical positioning noted) were omitted on more han 13.0% of the records. Given he observed inconsistencies, perhaps the anesthesia record needs redesign or the rationale behind documentation requires increased emphasis in educational and equally assurance programs.
Anesthesia↗
The dynamics of urban population.
The relative roles of natural increase and migration in determining the long-term dynamics of an urban population are considered. "Rogers' model is used to represent the simultaneous growth of a multiregional population. Exploiting the mathematical structure of the resulting system of difference equations, a perturbation theory for demographic models [is] outlined. This theory provides useful tools for analysing the sensitivity of stable population distribution and rate of growth to changes in the fundamental demographic parameters. With respect to the conventional approach to sensitivity analysis, it does not require the sometimes cumbersome calculation of matrix derivatives." A numerical example is given to demonstrate the method. (SUMMARY IN FRE AND ITA)
Demography↗
A multiregional population-projection framework that incorporates both migration and residential mobility streams: application to metropolitan city-suburb redistribution.
"In this paper the author introduces a population-projection framework that incorporates interregional migration and intraregional residential mobility streams to project future population sizes both across and within regions in a manner that is consistent with existing migration theory. The author presents a general matrix model of the framework, shows how its parameters can be estimated from fixed-interval census migration data, and discusses how the framework can be employed to 'update' population projections when recent, more limited data sets become available. These features of the framework are demonstrated with intrametropolitan central-city-suburb projections for selected US Standard Metropolitan Statistical Areas over the period, 1970-2020."
Americas↗
[The demographic behavior of linguistic groups in Quebec during].
"The purpose of this paper is to analyse simultaneously, according to what is known as the multiregional approach, the interactions between fertility, migration and mortality, for each of the main linguistic groups of Quebec [Canada]. Results show that, on the basis of the demographic regime observed between 1976 and 1981, while migration probably has reduced regional disparities in fertility and mortality behavior, it also has markedly amplified the demographic impact of linguistic disparities in this behavior." (SUMMARY IN ENG AND SPA)
Americas↗
Facial-motion analysis with a video and computer system: a preliminary report.
HYPOTHESIS: To investigate the feasibility of a video and computer-assisted system for evaluating the temporal and spatial aspects of facial motion during selected facial expressions in a pilot group of six normal adults. Evaluation of the diverse medical and surgical treatments for facial paralysis and paresis cannot occur until objective, reliable, and sensitive measures of the spatial and temporal aspects of facial function at specific facial landmarks are developed. METHODS: Facial motion at predetermined facial locations was assessed using a commercially available computer-interactive motion analysis system, which is based on videography principles. The displacement, velocity, and acceleration data were averaged across all trials and subjects. Time plots also were obtained for the left versus right side. RESULTS: The greatest mean maximum displacement (resultant vector) occurred during the eyebrow lift expression, reaching 1.2 cm in magnitude. The mean maximum velocity (resultant vector), which ranged from 4.5 to 8.5 cm/s for the dynamic facial expressions, was greatest for the eyes closed tight expression. The mean maximum acceleration (resultant vector), which ranged from 193 to 465 cm/s/s, was greatest for the eyebrow lift expression. Symmetrical time plots were obtained. The system documented synkinesis by revealing substantial left upper eyelid motion during the nose-wrinkle expression in an illustrative case with slight left facial dysfunction. CONCLUSION: This approach to facial motion analysis is feasible for the simultaneous, multiregional, spatial-temporal assessment of facial expressions. Because motion at relatively remote regions could be quantified, this approach is potentially useful for the evaluation of synkinesis.
Adult↗
The effect of vincamine on the regional cerebral blood flow in man.
The cerebral hemodynamic action of Vincamine is measured in 17 patients with primary or secondary cerebral circulation disorders, by use of the multiregional 133Xe clearance technique. The statistical analysis of the results justifies the grouping of all the cases and the distinction between reference, ischemic and hyperemic zones by determining for each subject a range of + or - 15% of his own mean regional cerebral blood flow. The drug, in a single injection in the internal carotid artery, shows a significant beneficial hemodynamic effect on the ischemic regions of the brain. No steal phenomenon is recorded in the middle cerebral artery territory. The action of the drug leads to a decrease and an equalization of the hemodynamic resistances of the cerebral vascular bed.
Adolescent↗
Net migration estimation in an extended, multiregional gravity model.
A multi-regional framework is developed in order to analyze net migration over time to all 10 Canadian provinces within an integrated system of equations. "An extended gravity model is the basis for the equation specification and the use of constrained econometric estimation techniques allows for the provincial interdependence of the migration decision while at the same time ensuring that an important system-wide requirement is respected." The model is estimated using official Canadian data for the 1960s and 1970s. "The results suggest the predominance of the push factor for interprovincial migration for most provinces, although net migration to the Atlantic provinces is also shown to be subject to pull forces from the rest of the country." The effects of wage rate variables, unemployment, and political disturbances in Quebec on inter-provincial migration are noted.
Americas↗
[The dynamics of multi-regional demographic systems--the case of a nonlinear migration model].
"To provide new insight into the evolution of multiregional population systems, this article presents a dynamic study of a nonlinear variant of the components-of-change model. In this variant, migrants out of a region do not distribute themselves among destination regions in constant proportions (as in the classical linear variant). Rather their allocation is proportional to that of population (weighted so as to account for the difficulty to move between regions). The analysis focuses on the existence, characteristics, and determination of equilibrium states. It is illustrated with an application to the population of Canada and its five large regions." (summary in ENG)
Americas↗
Multiregional origin of B chromosomes in the grasshopper Eyprepocnemis plorans.
Analysis of chromosome localization of three molecular markers, 18S-5.8S-28S rDNA, 5S rDNA and a 180 bp satDNA, showed that B chromosomes in the grasshopper Eyprepocnemis plorans originated independently in Eastern (Caucasus) and Western (Spain and Morocco) populations. Eastern B chromosomes are most likely derived from the smallest autosome, which is the only A chromosome carrying the three markers, in coincidence with Caucasian B chromosomes. Western B chromosomes, however, lack 5S rDNA and are most likely derived from the X chromosome, which is the only A chromosome carrying the two remaining markers, always in the same order with respect to the centromere, as the B chromosome.
Animals↗
Absence of regional affinities of Neandertal DNA with living humans does not reject multiregional evolution.
The recent extraction of mitochondrial DNA sequences from three European Neandertal fossils has led many to the conclusion that ancient DNA analysis supports the African replacement model of modern human origins and rejects models of multiregional evolution that propose some Neandertal ancestry in living humans. This conclusion is based, in part, on the lack of regional affinity of Neandertal DNA to that from living Europeans. Consideration of migration matrix models shows that this conclusion is premature, since under a model of interregional gene flow we expect to see similar levels of Neandertal ancestry in all contemporary regions, and living Europeans should not necessarily show closer affinity. The absence of regional affinity in Neandertal DNA does not distinguish between replacement and multiregional models.
Africa↗