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At least 613 records · Page 34Linked to original sources
PubMed1989

Histologic, morphometric, and immunocytochemical analysis of myometrial development in rats and mice: II. Effects of DES on development.

The effects of diethylstilbestrol (DES) treatment on myometrial development from the prenatal to adult period were examined in rats and mice by histologic and immunocytochemical methods using anti-actin, -vimentin, and -laminin to assess cytodifferentiation of smooth muscle and fibroblastic cells, and by morphometric procedures to assess quantitatively the effect of DES on the expression of cellular orientation in the emerging inner circular myometrial layer. Neonatal rats and mice were treated with DES from day 0 (day of birth) to day 2 with dosages known to perturb myometrial development. Neonatal treatment with DES increased the degree of circular orientation within the uterine mesenchyme, an effect detectable following as little as 24 hr of DES treatment. This effect on spatial organization of the mesenchyme was followed by an increase in the thickness of the actin-positive middle layer (prospective circular myometrium) of uterine mesenchyme during days 3-15; from day 15 onward, however, the circular myometrial layer began to fragment into irregular bundles of smooth muscle, and the longitudinal myometrial layer became thinner and more irregularly organized than controls. Vimentin localization in rats treated with DES neonatally was more intense than in controls within the circularly orientated uterine mesenchyme at 5 days. By 60 days the circular and longitudinal myometrial layers of DES-treated animals showed strands and bundles of vimentin-positive cells, which were not present in controls. Both rats and mice show comparable effects of DES treatment.

Animals↗
PubMed1994

Development of the inlet portion of the right ventricle in the embryonic rat heart: the basis for tricuspid valve development.

BACKGROUND: Before septation the entire atrioventricular canal is connected with the ventricular inlet segment (primitive left ventricle) whereas the mature heart exhibits an exclusive connection of the right atrium to the right ventricle. The process which is responsible for this change is controversial. METHODS: Graphic reconstructions of serially sectioned embryonic rat hearts as well as scanning electron micrographs of similar specimens were made. RESULTS: The first indication of a right atrioventricular connection was seen as a groove in the atrioventricular junctional myocardium to the right of the inferior endocardial cushion. This groove expanded to form the right ventricular inlet portion. The right, inferior, and superior walls of this newly formed cavity were formed from junctional myocardium, which demarcated it from the trabeculated right ventricular portion in all developmental stages. The left wall equally developed from this junctional myocardium and formed the ventricular inlet septum. The junctional myocardium between right ventricular inlet and trabeculated portions was seen to develop into the tricuspid valve and its tension apparatus. CONCLUSIONS: The preseptation embryonic heart has no inlet portion to the right ventricle. This new cavity is created by remodelling of atrioventricular junctional myocardium. This myocardium also provides the material contribution to the tricuspid valve and its tension apparatus. Malformations of the right ventricular inlet portion and of the tricuspid valve are indissolubly linked.

Animals↗
PubMed1976

Evaluating drugs and determining the drug needs of developed and developing countries.

The practice of reviewing drug utilization provides a surveillance system for monitoring the efficiency of drug distribution and drug consumption; it also provides a data base for the interpretation of the frequency of adverse drug reactions and helps to identify gaps in the delivery of a crucial aspect of health services: the provision of safe and efficacious medicines. Malconsumption (either over- or under-utilization or needless prescribing) can be identified and economies might be achieved, once these problems are corrected. Linking drug utilization with standard health indices, such as morbidity and mortality rates, can help assess the effects of widely used drugs, both adverse and beneficial. Drug utilization review should be considered an essential activity of a well-organized health delivery system; it has great potential for both health planning and evaluation. These positions are discussed as they relate to developed and developing countries.

Developing Countries↗
PubMed1987

Development and use of shell-less quail chorio-allantoic-membrane cultures to study developing skeletal tissues; a qualitative study.

A technique is described for in vitro culture of the quail embryo from the 1st to the 18th day of development. The embryos are cultured in Teflon hammocks, suspended in glass supports and kept in a humidified atmosphere at 36.5 degrees C. The quail CAM is used as support and cell source for developing non-quail cartilage and bone. The quail cells can be identified histologically and easily recognized by Feulgen-staining which is demonstrated in the presence of quail chondro- or osteoclasts in a mouse long bone rudiment cultured on the CAM.

Allantois↗
PubMed1994

Studies of the epidemiology of dementia: comparisons between developed and developing countries.

By the year 2025, 68% of the world's population aged 65 and above, nearly 277 million people, will be residing in developing countries. The less industrialized nations have been the least studied to date, and may yield significant new information about the etiology and risk factors for Alzheimer's disease (AD) and other dementias. Although it is readily apparent that cross-national and cross-cultural comparisons are desirable, these can be meaningful only if based on comparable methodology. In this work we will discuss some general conceptual and methodological issues regarding epidemiological studies of dementia in developing countries. The topics discussed include community-based screening for dementia, screening instruments and their application in cross-cultural studies, steps in standardization of new or modified neuropsychological tests, and some special considerations in studying uneducated/illiterate populations.

Aged↗
PubMed1994

Development of the locomotory muscle of the chaetognath Sagitta. 1. Quantitative and qualitative aspects of the body and muscle tissue development within the phylum.

The Chaetognath primary muscle constitutes the main tissue of the body-wall. It is made up of four main longitudinal bands. Muscle fibres are separated from the nervous system. During muscle growth, four myogenic zones produce two types of fibres A and B, forming units. These units ordered in an epithelial-like tissue, show various kind of intercellular junctions. For a given animal, the overall number of A and B fibres units is practically the same in each band. The four myogenic areas are the centre for a two-phase production of A and B fibres which appear at a regular rate in each quadrant, by the simultaneous production of three sets of A fibres and two sets of B fibres. The former differentiate at once, the latter some time later, and always at the same moment in their lives. In this way the number of sets of A and B fibres increases during the animal's life. This hyperplasia is accompanied by the hypertrophy of the cells which make up each group. For any given animal, the ventral quadrants are thicker than the dorsal quadrants. Chaetognath locomotory muscle is a good model on which to study the development of a skeletal muscle. Its development is closely related to the hydroskeleton growth, to the animal's shape and various other constructional factors which play a central role in this very isolated phylum.

Animals↗
PubMed1996

Development of striatal dopaminergic function. II: Dopaminergic regulation of transcription of the immediate early gene zif268 and of D1 (D1a) and D2 (D2a) receptors during pre- and postnatal development.

We investigated cocaine- and apomorphine-mediated induction of the zinc finger immediate early gene (IEG), zif268, during striatal ontogeny. Acute cocaine or apomorphine treatment increased striatal zif268 mRNA on embryonic day 20 (E20), postnatal day 5 (P5), and in adults, but not on E15, with developmentally distinct anatomical profiles. SCH23390 pretreatment completely attenuated zif268 gene expression at all ages, but eticlopride treatment of E20 and P5 rats prior to cocaine enhanced zif268 expression beyond that observed with cocaine alone. In adults, eticlopride pretreatment partially attenuated the cocaine-mediated increase in zif268 expression. E20 and P5 D2 receptors appear to be negatively coupled to zif268 expression; whereas the adult D2 receptor, like the D1 receptor, appears to stimulate zif268 expression. Acute cocaine increased D1 but not D2 receptor mRNA levels within 24 h but had no effect on D1 or D2 receptor binding. By late embryonic development, some striatal neurons possess DA receptors coupled to IEG (zif268) activation. Postnatally, D1 receptor activation consistently increases zif268 transcription, but the coupling of D2 receptors to zif268 changes from decidedly negative at an early postnatal age to slightly positive in adults. These results are consistent with a role for DA in regulating striatal neuronal differentiation and development.

Animals↗
PubMed1980

The development of pharmacological and chemical research for application to traditional medicine in developing countries.

The resolution of the 31st WHO Assembly requests: (1) a complete inventory of medicinal plants, (2) evaluation of efficacy and safety of the plants, (3) standardization of the plants. This involves a great effort, not only from developing but also from industrialized countries, being a task which will take many years and the full-time dedication of many researchers. Any research on the use of plants in traditional medicine should be developed in the framework of the activity of WHO. An example of this type of collaboration is the organization of research on fertility regulating plants in which six universities in different regions of th world are interested. This work must be done in such a way that industry should play a role, because of its greater knowledge of modern technologies, which may lead to a better utilization of plants and their extracts, and its funding and marketing abilities.

Animals↗
PubMed1990

Rod photoreceptor development in vitro: intrinsic properties of proliferating neuroepithelial cells change as development proceeds in the rat retina.

We describe a reaggregated cell culture system in which retinal neuroepithelial cells from embryonic rats proliferate extensively and give rise to rod photoreceptors on the same schedule in vitro as they do in vivo. Both the proliferative potential of the embryonic neuroepithelial cells and the timing of their differentiation into rods are not changed by the presence of a 50-fold excess of neonatal neural retinal cells, although many more of the embryonic cells develop into rods in these circumstances. In such mixed-age cultures, dividing neonatal cells proliferate much less and give rise to rods much sooner than do dividing embryonic cells, suggesting that the dividing cells at the two ages are intrinsically different. These and other findings suggest that both cell-cell interactions and an intrinsic program in neuroepithelial cells determine cell fate in the developing rat retina.

Aging↗
PubMed1994

Early CNS development: distal-less related genes and forebrain development.

The ever increasing number of molecular markers available for the study of developing structures is revolutionizing developmental neurobiology. It is now possible to identify entirely new groups of cells and trace their lineages among all other cell populations. Recent studies on the expression domains of a variety of genes specifically expressed in the developing CNS are beginning to give us a better understanding of the early regionalization of the CNS and, in particular, of the forebrain.

Amino Acid Sequence↗
PubMed2006

The influence of economic development level, household wealth and maternal education on child health in the developing world.

This study estimates the relative importance to child health (indicated by weight and height for age) of economic development level [gross domestic product (GDP) converted to international dollars using purchasing power parity (PPP) rates: GDP-PPP], household wealth and maternal education and examines the modifying influence of national contexts on these estimates. It uses information collected from mothers aged 15-49-years participating in Demographic Health Surveys (DHS) conducted in 42 developing countries. In multilevel regression models, the three study variables exhibited strong independent associations with child health: GDP-PPP accounted for the largest amount of unique variation, followed by maternal education and household wealth. There was also substantial overlap (shared variance) between maternal education and the other two study variables. The regressions of child health on household wealth and maternal education exhibited substantial cross-national variation in both strength and form of association. Although higher education levels were associated with disproportionately greater returns to child health, the pattern for household wealth was erratic: in many countries there were diminishing returns to child health at higher levels of household wealth. We conclude that there are inextricable links among different strategies for improving child health and that policy planners, associating benefits with these strategies, must take into account the strong moderating impact of national context.

Adolescent↗
PubMed2005

Imaging the developing brain: what have we learned about cognitive development?

The human brain undergoes significant changes in both its structural architecture and functional organization across the life span. Advances in neuroimaging techniques over the past decade have allowed us to track these changes safely in the human in vivo. We review the imaging literature on the neurobiology of cognitive development, focusing specifically on cognitive task-dependent changes observed in brain physiology and anatomy across childhood and adolescence. The findings suggest that cortical function becomes fine-tuned with development. Brain regions associated with more basic functions such as sensory and motor processes mature first, followed by association areas involved in top-down control of behavior.

Adolescent↗
PubMed1996

Developing behavioral objectives for perioperative staff development.

Behavioral objectives (i.e., clear statements that describe intended instructional outcomes) are a crucial component of educational planning for perioperative staff development. Properly written objectives promote positive learning outcomes such as increased motivation, better retention of information, and improved instructional accountability. This article describes the advantages of using behavioral objectives, gives a historical perspective of their development, presents a practical "how-to" approach to formulating them, and delineates their link to the selection of appropriate evaluation methods.

Behavior↗
PubMed2002

Tracheal development in Drosophila melanogaster as a model system for studying the development of a branched organ.

The development of the tracheal system of Drosophila melanogaster represents a paradigm for studying the molecular mechanisms involved in the formation of a branched tubular network. Tracheogenesis has been characterized at the morphological, cellular and genetic level and a series of successive, but linked events have been described as the basis for the formation of the complex network of tubules which extend over the entire organism. Tracheal cells stop to divide early in the process of tracheogenesis and the formation of the interconnected network requires highly controlled cell migration events and cell shape changes. A number of genes involved in these two processes have been identified but in order to obtain a more complete view of branching morphogenesis, many more genes carrying essential functions have to be isolated and characterized. Here, we provide a progress report on our attempts to identify further genes expressed in the tracheal system. We show that empty spiracles (ems), a head gap gene, is required for the formation of a specific tracheal branch, the visceral branch. We also identified a Sulfotransferase and a Multiple Inositol Polyphosphate phosphatase that are strongly upregulated in tracheal cells and discuss their possible involvement in tracheal development.

Animals↗
PubMed2003

Burden of Helicobacter pylori and H. pylori-related diseases in developed countries: recent developments and future implications.

Helicobacter pylori colonizes the gastric mucosa. H. pylori infection is the main cause of peptic ulcer and gastric malignancy. This review gives an overview on the epidemiology of H. pylori infection and H. pylori-associated diseases in the developed world, mainly Europe, and it discusses very recent developments with regard to the prevalence and its future implications for H. pylori-associated diseases.

Adolescent↗
PubMed2000

Development and validation of the Self-Identity Inventory (SII): a multicultural identity development instrument.

The Self-Identity Inventory (SII) was developed using the Optimal Theory Applied to Identity Development (OTAID) model. A sample of 325 culturally diverse respondents completed the SII, the Tolerance Scale from the California Psychological Inventory, the Belief Systems Analysis Scale, and the Social Desirability and Infrequency Scales. Through confirmatory factor analysis, goodness-of-fit, and social desirability/item infrequency measures, SII items were analyzed, resulting in a 6-scale, 71-item inventory. Internal consistency for the scales ranged from .72 to .90. Test-retest reliability ranged from .72 to .92. Correlations with external construct validity measures supported predictions. Interscale correlations and other statistical tests primarily supported the OTAID model. Implications for therapy and future research are suggested.

Adolescent↗