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PubMed1991

Comparison on collagen gene expression in the developing chick embryo tendon and heart. Tissue and development time-dependent action of dexamethasone.

Glucocorticoids modulate various cellular functions such as proliferation, energy metabolism and the synthesis of proteins. In the present study, the response of collagen genes to dexamethasone in different stages of chick embryo development was studied in tendon and heart using Northern blot analysis and specific cDNA probes. The changes in collagen gene expression were compared to alterations in two reference mRNAs: actin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The levels of specific mRNAs measured per ribosomal RNA in tendon and heart varied markedly during normal development. In tendon the relative levels of alpha 1(I), alpha 2(I) and alpha 1(III) collagen mRNAs were highest between days 14-16 when also the synthesis of matrix proteins is most active. In heart the levels of these mRNAs peaked at day 12. In addition, qualitative differences were observed in the expression of actin genes between tendon and heart. Dexamethasone in high dose decreased collagen mRNA levels in tendons, while in heart a stimulatory effect was noted. Dexamethasone also decreased GAPDH mRNA levels in tendons. The alterations in gene expression after dexamethasone treatment in tendon and heart did not correlate with the level of specific glucocorticoid receptors, which varied markedly during the development of chick embryos. The cDNA for pro alpha 1(I) collagen hybridized to two transcripts corresponding to 6.2 and 5.1 kb in tendon and heart. During normal development of chick embryos the ratio of 6.2/5.1 kb mRNAs decreased markedly in heart, but no such change was observed in tendons. Dexamethasone, however, decreased the ratio of 6.2/5.1 kb transcripts in tendons. There was a significant correlation between the ratio 6.2/5.1 kb transcripts and total alpha 1(I) mRNA both in tendon and heart, suggesting that the 6.2 kb transcript may be associated with the rate of synthesis of type I collagen.

Actins↗

PubMed1991

Expression of two members of the Wnt family during mouse development--restricted temporal and spatial patterns in the developing neural tube.

The Wnt gene family encodes a group of cysteine-rich proteins implicated in intercellular signaling during several stages of vertebrate development. This family includes Wnt-1 and Wnt-3, both discovered as activated oncogenes in mouse mammary tumors. Here we describe the molecular cloning of an additional member of the Wnt family, called Wnt-3A, and the spatial and temporal expression pattern of this gene as well as that of its close relative Wnt-3. The putative amino acid sequences of both proteins are almost 90% identical, but in situ hybridization to mouse embryo sections showed highly restricted patterns of expression of Wnt-3 and Wnt-3A, largely in separate areas in the developing nervous system. In the spinal cord Wnt-3 was expressed at low levels in the alar laminae and in the ventral horns, whereas Wnt-3A expression was confined to the roof plate. In the developing brain Wnt-3 was expressed broadly across the dorsal portion of the neural tube with a rostral boundary of expression at the diencephalon. In contrast, Wnt-3A was expressed in a narrow region very close to the midline; expression extended into the bifurcating telencephalon, in a highly localized fashion. Both Wnt-3 and Wnt-3A were expressed in the ectoderm, and Wnt-3A was also expressed in the periumbilical mesenchyme. Characteristic expression patterns of these two closely related genes suggest that Wnt-3 and Wnt-3A play distinct roles in cell-cell signaling during morphogenesis of the developing neural tube.

Amino Acid Sequence↗

PubMed1992

Early heart development in the chick embryo: effects of isotretinoin on cell proliferation, alpha-actin synthesis, and development of contractions.

Isotretinoin is a potent retinoic acid used in the treatment of skin disorders. Though very effective, it is teratogenic if administered during pregnancy, and its teratogenic effect may be related to the normal activity of retinoids as signalling molecules in the embryo. Although its exact mechanism of action is unknown, it has been suggested that it causes its characteristic pattern of defects that includes heart defects, by inhibiting the migration of neural crest cells. However, other effects on cells are known. We studied early cardiac cell proliferation using incorporation of bromodeoxyuridine (BrdU) and detection with a monoclonal anti-BrdU. Proliferation in heart tissue of whole embryo cultures was inhibited in medium with 10(-6) M isotretinoin to 62% of the control level in myocardium. We studied its effects in culture on precardiac explant development in the absence of the neural crests. Culture of precardiac mesodermal-endodermal explants revealed that development of heart vesicles from the mesoderm was little affected, but the development of heartbeat was inhibited depending on dose in the 10(-5) to 10(-7) M range. The effect on development of contractions was augmented in the presence of serum; it could be duplicated by all-trans-retinoic acid, and it was reversible. Synthesis of the alpha-actin isotype, analyzed by isoelectric focusing, was found to be inhibited or delayed. The results suggest multiple effects of retinoids on growth, morphogenesis, and differentiation of early cardiac tissue, and are discussed in relation to the potential role of retinoids in early embryogenesis.

Actins↗

PubMed1979

Development and aging of cholinergic synapses. I. Endogenous levels of acetylcholine and choline in developing autonomic ganglia and iris of the chick.

Acetylcholine (ACh) and choline (Ch) levels were measured by means of a sensitive micromethod in developing irises, ciliary and sympathetic ganglia of the chick, starting at 5--7 days of incubation (DI) up to 1 year of age. The neurotransmitter is present in all three organs at relatively low levels (1--10 pmol) from 5 DI (iris) or 7 DI (ciliary and sympathetic ganglion). This is followed by a rapid and sustained 9-fold increase in all three tissues up to 14 DI. Thus, it appears that low levels of ACh may be sufficient for neurotransmission to occur in the primitive ciliary ganglion and iris. After hatching, total ACh levels continue to increase up to 1 year of age in the iris and ciliary ganglion and up to 3 months in the sympathetic ganglion. The increase may depend on either an increased functional demand for the neurotransmitter or an increased number of preganglionic terminals. In general Ch levels parallel closely the levels of ACh in each organ throughout development. It is concluded that ACh and Ch are present since the earliest detectable stages of development in the ganglia and iris, and their first increase seems to be correlated to the phase of innervation of the organs. The subsequent increase probably correlates to synaptogenesis. The close relationship between Ch and ACh levels indicates a regulatory role of Ch for ACh synthesis during neuronal development.

Acetylcholine↗

PubMed1975

Moral development and perceptual role-taking egocentrism: their development and interrelationship across the life-span.

Moral judgments and perceptual role taking egocentrism were assessed in seventy-two middle-class people whose age range encompassed a significant portion of the life span. Findings support the anticipated curvilinear relationship between moral development and age, and egocentrism and age. However, the close conceptual development and age, and egocentrism and age. However, the close conceptual relationship between moral development and egocentrism throughout life received only slight statistical support, which attained significance only in the fifteen- to nineteen-year-old age group. The existence of "self-involving" egocentrism was postulated to be an important determinant or moral development during adulthood.

Adolescent↗

PubMed1991

Development of multipotential haemopoietic stem cells to neutrophils is associated with increased expression of receptors for granulocyte macrophage colony-stimulating factor: altered biological responses to GM-CSF during development.

Interleukin-3 (IL-3) dependent multipotent haemopoietic stem cells FDCP-Mix A4 (A4) were induced to differentiate and develop into mature neutrophils in response to Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) plus granulocyte CSF (G-CSF). This resulted in an increase in cell number over seven days of culture, following which the cells lost the ability to undergo further proliferation. The effect of GM-CSF on these cells has been assessed at various stages of development. Clonogenic cells, able to respond to GM-CSF, were generated only at days 3, 4 post-induction. From day 5 onwards, mature post-mitotic neutrophils are produced and clonogenic cells are lost. Loss of proliferative potential, in response to GM-CSF, was confirmed using [3H]-thymidine incorporation. Receptors for GM-CSF, were also measured during development using [125I]-GM-CSF binding assays. Although the dissociation constant for GM-CSF binding sites did not vary considerably, the number of such sites increased dramatically from about 20 (day 0, when the cells have a primitive morphology) to about 1000 by day 6 (when the cells are predominantly mature neutrophils). GM-CSF-stimulated Na+/H+ antiport activation was also determined. Although few GM-CSF receptors are expressed at day 0, there is a significant response (63% of maximal) to GM-CSF in terms of intracellular alkalinisation: this response increased markedly until, by day 4 (700 GM-CSF binding sites/cell), there is a maximal activation of the antiport by GM-CSF. By day 7 (greater than 900 GM-CSF binding sites/cell), however, there is significant reduction in activation of the Na+/H+ antiport by GM-CSF. Nonetheless, increased viability of these mature cells is still seen in response to GM-CSF. These results suggest that not only does expression of GM-CSF receptors alter during development of multipotential cells to mature neutrophils, but that these receptors are coupled to different intracellular effector mechanisms as the cells progressively mature.

Cell Differentiation↗

PubMed1976

[Development of the neuronal structure of the hippocampus during pre- and post-natal ontogenesis in the albino rat. I. Neurohistological demonstration of the development of lung-axonal neurons in the CA3 and CA4 regions].

In this paper qualitative investigations by means of light microscopy (Golgi impregnation) considering the ontogenesis of efferent neurons of the CA3, CA4a, CA4b regions in the rat hippocampus are presented following the already described development of CA1 pyramids (MINKWITZ and HOLZ 1975). After the migration of neuroblasts the types of projective neurons can be distinguished in the mentioned regions at the end of the prenatal period. During the first postnatal time particularly the basal dendritic tree develops expressing more distinctly the typical forms of pyramids (CA3, CA4a) and the of the multipolare neurons of CA4b. No distinct qualitative jumps at the transition of the regions in contrast to the CA3--CA1 boundary can be observed. Temporal retardations in the appearance of postsynaptic structures (microdendrites, excrescenses, spines) at pyramidal neurons from CA4 to CA3 and CA1 are regarded as signs of earlier development of the phylogenetic older pool of cells. During the early postnatal developmental period (until stage P10) proceedings of the growth are predominant. Later on, during the late postnatal period, the maturation of the neurons takes place with a considerable multiplication of spines distributed in similar ways as known from other pyramids. At stage P20 neurons of all hippocampal regions cannot be distinguished from adult ones without using morphometric procedures. The development of parts of the intrahippocampal network including mossy fibre system and SCHAFFER collaterals is discussed with regard to in this way appearing boundaries between fascia dentata and regio inferior CA4, CA3) and regio superior (CA1). These fibre systems establish by their stepwise construction one of the basic elements to hippocampal functioning.

Age Factors↗

PubMed1975

[The relationship between the development of the clinical picture of the disease and the rate of development of the intracranial focus (an experimental study)].

Experiments on 53 dogs with a slowly increasing limited brain cavity depicted some traits in the development of intracranial hypertension and in the clinical development of the disease with regard to the rate of intensification of the focus. The rate of an increasing focus exerts great influence on the correlation between the duration of the period of larvated (compensated) and manifest development of the pathological by volume process in the brain cavity. The author distinguishes 4 types in the development of the disease: chronic, subacute, acute and stroke-like conditioned by the degree of expressiveness in the compensatory mechanisms and factors leading to a breakdown of compensation.

Acute Disease↗

PubMed1976

Studies on the development of endocrine glands in fishes. V. Development of the thyroid gland in two species of teleosts.

In Channa punctatus the thyroid anlage is seen 40 h after hatching and is recognized as cells aggregating in the form of follicles with no colloid. During subsequent stages of development the thyroid follicles increase in number and in 5 days old larva an active division of cells and many follicles in the form of epithelial cords are seen. In 2 months old juvenile fish several thyroid follicles and lymphatic vessels are seen enclosed by connective tissue capsule. In Clarias batrachus the thyroid anlage is seen as a group of cells around tiny colloid droplets and is situated just below the bifuration of the 1st branchial artery. This stage is seen in 60 h old larva and is developed into thyroid follicles which is a long chain along the jugular vein and ventral aorta during latter stages of development. It is concluded that during early larval period of these fishes, the thyroid cells begin to trap iodine from the blood and synthesize it in the form of thyroid hormone which is stored as colloid and is also liberated in blood stream simultaneously. The compact nature of the thyroid gland in C. punctatus is because of development of connective sheath around follicles during early stages.

Animals↗

PubMed1991

A flourishing time for flower development. Workshop on Flower Development, sponsored by Fundación Juan March, Madrid, Spain, March 11-13, 1991.

Molecular genetics has recently erupted in the field of flower development, an area of research traditionally cultivated by plant physiologists. The isolation and molecular characterization of seven homeotic genes (four in Antirrhinum majus and three in Arabidopsis thaliana) that control both floral organogenesis and the transition from inflorescences to floral meristems is leading to major breakthroughs in the understanding of the mechanisms governing flower development. This has already had a great impact among plant physiologists, who are incorporating mutant analysis into studies of floral induction and flower development. We are still missing data about the nature of the pollen product of the S-locus in self-incompatibility systems, although current experimental approaches might provide this information in the near future. Gene technology appears to have a high potential in hybrid seed production through the construction of male sterile plants as well as of plants able to restore fertility. The study of genes regulating pigment formation in flowers continues to provide interesting data on gene expression in plants, in which phenomena such as co-suppression and methylation seem to play an important role. Altogether, one can predict that very exciting times are coming in the field of flower development.

Gene Expression Regulation↗

PubMed1991

Seroepidemiology of Helicobacter pylori infection in India. Comparison of developing and developed countries.

Helicobacter pylori (previously Campylobacter pylori) is now accepted as the major cause of type B gastritis and thus what is known about the epidemiology of type B gastritis can reasonably be transferred to H. pylori. We used a specific ELISA for anti-H. pylori IgG to study the prevalence of H. pylori infection in a population of lower socioeconomic class from Hyderabad, India. The results from India were compared to studies from other parts of the world. Two hundred thirty-eight individuals ages 3 to 70 participated. The frequency of H. pylori infection increased with age (P less than 0.01) and was greater than 80% by age 20. H. pylori infection was present in 79% of the population studied; there was no gender-related difference in prevalence of H. pylori infection. IgG antibody against hepatitis A (HAV) was rapidly acquired in Hyderabad; in a subset of 58 children between the ages of 3 and 21 tested, the frequency of anti-HAV was 98.2%. The prevalence of H. pylori infection increases with age in both developed and developing countries. The high age-specific prevalence of H. pylori infection in developing countries is probably a reflection of the lower socioeconomic level of those areas.

Developing Countries↗

PubMed1992

EUROMAC. A European concerted action: maternal alcohol consumption and its relation to the outcome of pregnancy and child development at 18 months. Results--child development at age 18 months.

Children seen in the first part of the study in Berlin, Dundee and Odense were followed up at age 18 months and tested using the Bayley Scales of Infant Development. Five scores were recorded: the Mental Development Index (MDI), the Psychomotor Development Index (PDI) and scores for responsiveness, attention span and activity. The data were analysed for the centres combined and separately, allowing for confounding variables as in the previous chapter. In none of the comparisons was the mean score found to be significantly less in the children of drinkers than in those of abstainers. In many of the comparisons the children of abstainers had the lowest mean scores. In a number of comparisons in Berlin and Dundee, the MDI or PDI was found to be significantly higher in the children of women who had drunk at the upper end of the consumption distribution.

Alcohol Drinking↗

PubMed1991

Swedish Agency for Research Cooperation with Developing Countries. Prospects for public health benefits in developing countries from new vaccines against enteric infections.

The symposium participants concluded that vaccines with even moderate efficacy can be highly useful to prevent large numbers of severe illness episodes and deaths and that the decision of whether to initiate a vaccine program should be based on measures or estimates of public health effectiveness rather than only on protective efficacy. Studies of protective efficacy are of course critical to establish the vaccine's biologic activity, but additional aspects of public health effectiveness are also crucial in making these decisions. First-generation vaccines are available against typhoid, cholera, and soon rotavirus diarrhea, and vaccines against enterotoxigenic E. coli diarrhea and shigellosis are under development. The problems related to enteric diseases are enormous; the vaccines may soon be produced at low cost and promise to be relatively more easy to distribute than most previous vaccines. The number of illnesses and deaths averted from vaccine programs are potentially great. Pilot programs using the new vaccines should urgently be considered in areas where the disease burden is high, and steps should be taken to monitor effectiveness of the intervention in these programs. Such studies of vaccine effectiveness and costs in a "real world" situation are an essential step of the research process and should be used to guide the organization of larger-scale programs. Finally, many of the necessary research and development activities relevant to public health vaccinology must address country-specific problems. Developing countries should consider the role of vaccine-related research among the priorities for their essential national health research and build the necessary capabilities in applied and basic medical sciences and in the social sciences.(ABSTRACT TRUNCATED AT 250 WORDS)

Cost-Benefit Analysis↗

PubMed1991

Impact of preschool education component in Integrated Child Development Services programme on the cognitive development of children.

Integrated Child Development Services (ICDS) is India's most comprehensive programme to increase the survival rate and enhance the health, nutrition, and learning opportunities of pre-school children and their mothers through a package of services. The present study was carried out to measure the impact of the preschool education component of the ICDS on the cognitive development of children in the age group of 3-5 years. The study design used was case/control (ICDS attending children v. Non-ICDS). Results of the study revealed the ICDS Anganwadi attendance had positive influence on the cognitive development of children. The mean cognitive score of the attenders was 40.7 as against a mean score of 30.3 in the case of non-attenders.

Age Factors↗

PubMedDate not supplied

Sexual development and activity of men with disturbances of somatic development.

By means of Questionnaires HTDM and SAM the heterosexual development and sexual activity were investigated in the following groups of males: 1. the control group consists of 345 married men from sterile marriages, who were adequately developed somatosexually, had normozoospermia in the ejaculate and a good potency; 2. in 48 unilateral and 57 bilateral adult cryptorchids; 3. in 101 married men with a distinct testicular hypoplasia, the long axis of both sexual glands being shorter than 30 mm; 4. in 110 patients with a Klinefelter's syndrome; 5. in 14 patients with hypogonadotropic hypogonadism. Whereas the retardation of heterosexual development was found only in two groups (group 4 and 5), a distinctly lowered activity in sex life was ascertained in all four pathological samples.

Adult↗

PubMed1991

Development and validation of a simple device to estimate birthweight and screen for low birthweight in developing countries.

Low birthweight (less than 2500 g) is the major factor associated with the death of infants within the first 4 weeks of life. The mean birthweight of newborn babies of a certain geographic area reflects the quality of maternal and child health care service as well as the degree of socioeconomic development of that particular region. Hence, birthweight is being used increasingly as an indicator for health and socioeconomic planning. However, in a developing country such as Thailand, two-fifths of the babies are delivered at home and are not weighed because scales are not available. To solve this problem in rural areas, a circular nomographic chart was developed with which the birthweight can be computed from a newborn baby's chest and mid-arm circumferences. Preliminary trials comparing these charts with standard baby scales showed a high degree of accuracy with sufficient sensitivity and specificity.

Arm↗

PubMed1991

How empathy, egocentrism, Kohlberg's moral development, and Erikson's psychosocial development are related to attitudes toward war.

In this exploratory study 91 students took a questionnaire which measured their feelings of oneness with all humanity, their egocentrism, level of moral development according to Kohlberg, psychosocial development according to Erikson, and their attitude toward war, diplomacy, the Gulf war, civilians and soldiers in the Gulf area, etc. The hypothesis that empathy with humankind leads to concern about those involved and opposition to war was supported. These individuals were more likely to endorse values expressed in Kohlberg's Level 6. Students endorsing Level 4, law-and-order mortality, especially if they had no friends overseas and used no news source other than the usual U.S. mass media, were more likely to be pro-war, believe President Bush and the military briefings, and opposite reliance on diplomacy. If people had experienced war, they were more frequently against it. However, hardship experienced, lack of egocentrism, believing in a greater good for a greater number of people (Kohlberg's Level 5), and Erikson's psychosocial development were not associated with students' orientation toward war. Further research is suggested.

Adult↗

PubMed1975

The effects of experimental unilateral anotia on skull development in the chick embryo. II. Essentials of the development of the chondrocranium in normal embryos of 7-20 days of incubation.

In order to be able to describe adequately the developmental anomalies of the chondrocranium in unilateral anotia in the chick embryo, it seemed necessary to describe the essentials of the normal chondrocranial development. The following observations proved to be different from the available descriptions: 1. the occipital processes do not fuse with the ear capsules; 2. the tectum synoticum fuses only with the ear capsules; the occipital processes fuse later with the tectum synoticum by outgrowth to dorsal; 3. in the chick embryo there is no evidence for the existence of a tectum posterius; 4. the metotic fissure is in the cartilaginous stage of development not closed, but shifts laterally; 5. there is strong evidence that the pro-otic processes arise as independent structures which later fuse with the ear capsules. The results of the study of the development of the chondrocranium in the embryos in which experimentally unilateral anotia is produced, will be described in a following paper.

Animals↗