Nuclear proteins during development: incorporation of leucine into histones of rainbow trout during early development.
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Animals↗
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Results for “Early development”
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[Development of the cranium in mousebirds (Coliidae, Coliiformes, Aves). I. Early development of the chondrocranium].
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Animals↗
The effect of ethanol upon early development in mice and rats. II. In vitro effect upon early postimplantation rat embryos.
The direct effect of ethanol upon in vitro cultured 9.5 day rat embryos was investigated (2, 4, 8 and 10% ethanol added to the culture medium). The main effects recorded were as follows: 1. Significant increase of the number of "dying" embryos (beating heart without yolk sac circulation); 2. No significant increase of mortality; 3. Significant increase of the number of living embryos with deficient blood circulation; 4. Significant retardation of coiling in living embryos with a significant dose-effect relation, when the effects of 20/00 and 80/00 ethanol were compared; 5. Lowering of the mean somite number in living embryos; 6. Various macro- and macroscopical pathological changes (mainly necrotic areas in the central nervous system).
Animals↗
Possible consequences of disruption of neuromuscular contacts in early development for motoneurone survival.
Motoneurones are known to die (1) during embryonic development (naturally occurring cell death), (2) early in postnatal development after axonal injury, and (3) as a consequence of disease such as SMA. Interactions with the target emerges as an important factor for survival of developing motoneurones. The evidence for the target dependence od of developing motoneurones will be presented and the mechanisms by which the muscle may regulate motoneurone survival discussed. Results that argue for the following proposal will be given: with maturation of the CNS motor activity in all mammals increases as do the functional demands on the motoneurones. The target muscle's role is to induce changes in the motoneurone to make it competent to respond to increased amounts of glutamate from excitatory inputs and thus allow it to carry out the tasks associated with its increased activity. A failure of the muscle to induce these changes in the motoneurone's phenotype in time may lead to motoneurone death. In addition new approaches that could (1) improve motoneurone survival, and (2) use embryonic grafts to replace the lost cells will be discussed.
Animals↗
Early development and developmental plasticity of the fasciculus gracilis in the North American opossum (Didelphis virginiana).
The first objective of the present study was to ask when axons of the fasciculus gracilis reach the nucleus gracilis in the North American opossum (Didelphis virginiana). When Fast Blue (FB) was injected into the lumbar cord on postnatal day (PD) 1 and the pups were killed 2 days later, labeled axons were present within a distinct fasciculus gracilis at thoracic and cervical levels of the cord. When comparable injections were made at PD3 or 5 and the pups were allowed to survive for the same time period, a few labeled axons could be followed to the caudal medulla where they were located dorsal to the presumptive nucleus gracilis. In order to verify these observations and to determine if any of the axons which innervate the nucleus gracilis early in development originate within dorsal root ganglia, we also employed cholera toxin conjugated to horseradish peroxidase (CT-HRP) to label dorsal root axons transganglionically. When CT-HRP was injected into the hindlimb on PD1 and the pups were maintained for 1 day prior to death and HRP histochemistry, labeled axons were present within the fasciculus gracilis at thoracic and cervical levels, but they could not be traced into the medulla. When comparable injections were made on PD3, and the pups were maintained for 2 days, labeled axons were present within the caudal medulla. Our second objective was to determine whether axons of the fasciculus gracilis grow through a lesion of their spinal pathway during early development. In one group of animals, the thoracic cord was transected at PD5, 8, 12, 20 and 26 and bilateral injections of Fast Blue (FB) were made four segments caudal to the lesion 30-40 days later. After a 3-5 day survival, the pups were killed and perfused so that the spinal cord and brainstem could be removed and sectioned for fluorescence microscopy. In all of the cases lesioned at PD5, axons of the fasciculus gracilis were labeled rostral to the site of transection and they could be followed to the nucleus gracilis. Evidence for growth of fasciculus gracilis axons into the caudal medulla was also seen in cases lesioned at PD8. In contrast, labeled axons were not observed rostral to the lesion when it was made at PD12 or at later stages of development. In order to verify that some of the axons which crossed the lesion originated within dorsal root ganglia, the thoracic cord was transected at PD5 in another group of animals and 7 days later, injections of CT-HRP were made into one of the hindlimbs. After a 3 day survival, labeled axons could be traced through the lesion site and into the caudal medulla. We conclude that axons of the fasciculus gracilis reach the nucleus gracilis by at least PD5 in the opossum and that they grow through a lesion of their spinal pathway when it is made at the same age or shortly thereafter. The critical period for such growth appears to end between PD8 and PD12.
Amidines↗
Production and endocrine role of inhibin during the early development of bull calves.
This study investigated the ontogeny of control of FSH secretion by inhibin during early prepubertal development of bulls by 1) measurements of circulating levels of inhibin and FSH from 1 to 13 wk of age, and 2) immunoneutralization of endogenous inhibin at 7, 21, 60, and 120 days of age. In addition, production and localization of inhibin in testes were examined by immunohistochemistry and Western blots at 7, 21, 60, and 120 days of age. Plasma immunoreactive inhibin levels were relatively low between 1 and 3 wk of age and then showed a tendency to rise (P < 0.1) from 4 wk of age. Circulating concentrations of FSH were low during 3 wk after birth and increased at 5 wk, remained high (P < 0.05) until 16 wk of age. Treatment with inhibin antiserum resulted in a significant (P < 0.05) increase in plasma FSH at 7, 21, 60, and 120 days of age compared to those following injection of control serum; however, the magnitude of the FSH rise after inhibin immunization was greater as bulls aged. There were no significant changes in plasma LH after inhibin immunization. An intense staining of inhibin alpha subunits was found in Sertoli cells within the solid seminiferous cords from 7 to 120 days of age, while no specific immune reaction was found in interstitial cells. Western blot analysis of testicular homogenates isolated from bulls 7-120 days of age revealed presence of a 28.5-kDa molecule that cross-reacted with inhibin alpha subunit and beta(B) subunit-specific antibodies. In this study, before 13 wk of age in bull calves, there was no inverse relationship between plasma concentrations of immunoreactive inhibin and FSH. However, the present immunization study clearly indicates that inhibin participates in the regulation of FSH secretion from infancy to early prepubertal stage, although the endocrine significance of inhibin becomes greater in older bulls. The results also indicate that the major production site of inhibin in the testis is Sertoli cells and that these cells produce inhibin that exerts a negative feedback effect on FSH secretion from early stages of development.
Aging↗
Different spatiotemporal expression of DOC2 genes in the developing rat brain argues for an additional, nonsynaptic role of DOC2B in early development.
DOC2A and DOC2B are two homologous genes implicated in synaptic vesicle exocytosis. Their complementary, nonoverlapping expression patterns in adult rat brain suggest that they exert similar functions in different neurons. We have analysed the expression pattern of the two genes in the developing rat brain by in situ hybridization. Unexpectedly, we found no parallel expression of the two genes during development. DOC2B mRNA was highly expressed as early as embryonic day 12 (E12) throughout the neuroepithelium, long before synaptic transmission is functional, and the expression remained abundant from E12 onwards. In contrast, faint expression of DOC2A transcripts was first detected at E17 in ventral brain areas, and it extended gradually to other brain structures in the sequence of their ontology, i.e. structures that had formed first also expressed DOC2A first. At postnatal day 3, both genes were highly expressed throughout the brain. This overlapping expression diverged to the complementary distribution of the adult brain. The temporal and spatial differences in expression point to a functional divergence between these homologous genes during brain development: the pattern of DOC2A is consistent with its proposed synaptic function, whereas that of DOC2B suggests an additional, nonsynaptic role in proliferating cells.
Aging↗
The RNA polymerases of Drosophila melanogaster during early development.
The enzymatic basis for the changing rates of RNA synthesis in early Drosophila development has been examined through a description of the multiple forms, relative proportions, and total and specific activities of the RNA polymerases of the Drosophila embryo. Six chromatographically identifiable forms of RNA polymerase are detectable in embryos (Forms Ia, Ib, IIa, IIb, IIIa, IIIb), one of which (Form IIa) appears to be cytoplasmically localized and is present only in unfertilized eggs and pregastrular embryos, while another (Form IIb) appears only at gastrulation and remains throughout the remainder of development. The total and specific activities of the embryonic RNA polymerases are related to the patterns of embryonic RNA synthesis and to the nuclear and cellular events of holometabolous development.
Animals↗
Analysis of the third and fourth cell cycles of mouse early development.
The third (4-cell) and fourth (8-cell) cell cycles of early mouse development have been analysed in populations of blastomeres synchronized to the preceding cleavage division. DNA content was measured microdensitometrically. The entry of blastomeres into these cell cycles showed considerable heterogeneity both within and between individual embryos. This heterogeneity was greater in the fourth than in the third cell cycle. The component phases of the third cell cycle were estimated as G1 = 1 h, S = 7 h, and G2 + M = 2-5 h, and those of the fourth cell cycle as G1 = 2 h, S = 7 h, and G2 + M = 1-3 h.
Animals↗
The maternal legacy to the embryo: cytoplasmic components and their effects on early development.
RNA molecules and proteins are accumulated in the oocyte cytoplasm during its growth phase and are used to sustain the early phases of embryonic development before embryo DNA transcription begins. This makes the oocyte a very special cell, quite different from somatic cells where RNA and proteins usually undergo a rapid turnover. To enable the storage and timely use of such stored molecules, various mechanisms are effective in the oocyte and are gradually being elucidated. Our understanding of such mechanisms is important for constantly improving therapy for human and animal reproductive disorders as well as for understanding the process of nuclear reprogramming during cloning procedure or stem cell generation. This review focuses on the various aspects of these regulatory processes in an attempt to give an overview of the present knowledge on post-transcriptional and post-translational mechanisms taking place during oocyte maturation and early development. Mechanisms such as cytoplasmic regulation of the poly(A) tail, RNA localization and protein phosphorylation are described in some detail. Because most data are available from lower species these are presented together with appropriate reference to the mammalian oocyte when data are known, or when important differences have been described.
Animals↗
Early development of immune system in pigs.
Prenatal and early postnatal immune system development has been studied in minipigs. First leukocytes were observed in the yolk sac and fetal liver (FL) on the 17th day of gestation, the majority of them being SWC3(+). The colonization of the thymus (TH) with leukocytes was observed 21 days later. Two waves of fetal TH colonization with pro-T cells were deduced from the frequency of thymocyte subsets. Thymic B cells and immunoglobulin-secreting cells (Ig-SC) were studied by flow cytometry and ELISPOT, respectively. When the total numbers of fetal Ig-SC were compared, the TH was identified as the main source of natural antibodies and the only site of IgA and IgG synthesis. In germ-free animals, the TH also represented the major site of IgG and IgA production and the number of Ig-SC was not influenced by colonization with microflora. FL and bone marrow were identified as primary B lymphopoietic sites. The phenotype of B precursors was characterized and pre-B II cells were shown to be the dominant mononuclear fraction between DG50 and DG105. In the periphery, relative proportions of lymphocyte subsets were determined. Studies in gnotobiotic piglets have revealed that the appearance of CD4(+)CD8(+) T cells and CD2(-) B cells is absolutely dependent on the contact of immune system with live viruses and bacteria, respectively.
Animals↗
Early development of an infant with 18q- syndrome.
The early intellectual and psychological development of an infant with 18q- syndrome is described. In this syndrome, which is a rare chromosomal disorder, there is a deletion of a portion of the long arm of chromosome 18. The few previously published accounts have indicated a varying degree of intellectual retardation. This child proved to be moderately delayed only and her development over the first 24 months of age is described in some detail. The family was receiving an intensive home advisory service offered to help maximize the development of pre-school handicapped infants in the area, and it is suggested that in general terms this particular disorder is not remarkably different in respect of psychological prognosis from the more common Down's syndrome, involving trisomy 21, and shows an equally favourable response to such a service. The peculiar appearance of such infants may, however, pose particular problems of parental adjustment.
Abnormalities, Multiple↗
Expression of extracellular matrix molecules and cell surface molecules in the olfactory nerve pathway during early development.
The spatial and temporal expression patterns of several extracellular matrix molecules--laminin and fibronectin and cell surface molecules, neural cell adhesion molecule (NCAM), L1, tenascin, chondroitin sulfate proteoglycan, and peanut agglutinin (PNA) binding sites--were investigated during early olfactory nerve development. NCAM and L1 have similar patterns: They are expressed in the olfactory nerve and on the olfactory receptor neurons (ORNs) commencing with the earliest olfactory axon outgrowth (E12-E15). Their expression patterns suggest that both NCAM and L1 are associated with extension and fasciculation of olfactory axons. A comparison of L1 and olfactory marker protein suggests that L1 is expressed predominantly on immature ORNs. Laminin has an unique punctate staining pattern in the developing olfactory pathway as early as E12. These laminin puncta might play a role in olfactory neurite outgrowth and guidance. At E14, when pioneer olfactory axons enter the brain, the laminin-positive meninges on the surface of the olfactory bulb primordium break down but remain intact in the rest of the telencephalon. This suggests a functional interaction between the olfactory axons and the glial-pial barrier. Fibronectin staining is diffuse throughout the cranial mesenchyme but is absent from the olfactory nerve pathway. No specific patterns of tenascin or chondroitin sulfate, were observed during early olfactory development. PNA binding sites were associated with olfactory axon fasciculation. The expression of several extracellular matrix molecules and cell surface molecules is spatially and temporally regulated in the developing olfactory system. These molecules, thus, may play functional roles in olfactory axon outgrowth, fasciculation, and/or guidance.
Animals↗
Tbx1 is expressed at multiple sites of epithelial-mesenchymal interaction during early development of the facial complex.
TBX1 encodes a T-box-containing transcription factor, which is thought to be a key player in the aetiology of the DiGeorge and Velocardiofacial syndromes (DGS/VCFS). In addition to defects affecting structures derived from the pharyngeal pouches, these patients exhibit varying degrees of facial dysmorphology and cleft palate. We have analysed the expression of murine Tbx1 during early facial development and found transcripts at sites of known epithelial-mesenchymal interaction. In particular, Tbx1 was expressed in epithelium of the early facial processes, including the fronto-nasal, medial and lateral nasal and palatine. Transcripts were also localised to the epithelium of developing tooth germs and hair follicles at several stages during their early development. Together, these expression domains suggest a role for Tbx1 in mediating epithelial-mesenchymal signalling in regions of the developing face, a finding which is consistent with the spectrum of facial deformity encountered amongst subjects affected by DGS/VCFS.
Animals↗
Effect of gossypol and its metabolite on in vitro early development of mouse embryos.
The purpose of this study was to examine the effect of gossypol and its metabolite on early in vitro mouse embryo development. One hundred and thirty-eight excellent quality mouse blastocysts were randomly assigned to five different treatments. Culture media were supplemented with 10% (V/N) normal steer serum. The embryos were cultured at 37 degrees C with an atmosphere of 5% O(2), 5% CO(2) and 90% N(2), and embryo development was examined and recorded at 12-h intervals for 72 h. The percentage of embryos that developed to expanded blastocyst (92%), hatching blastocyst (84%), and hatched blastocyst (76%) stages in control Ham's F-10 media was not different from that of embryos cultured in media containing 0.1 and 5 mug of gossypol; however, none of the embryos treated with 265 ng of gossypol metabolite (GM) developed beyond the blastocyst stage. A substantial decrease in the percentage of embryos reaching hatching blastocyst (29%) and hatched blastocyst (29%) stages was observed in the embryos cultured with 5.3 ng of GM. At both light and electron microscopic levels, the embryos appeared to be affected even by a lower concentration of GM in vitro. Our results suggest that GM has a much greater potency than the parent gossypol in inhibiting the early development of mouse embryos in vitro.
Journal Article↗
The effects of cryopreservation on early development and chromosome constitution in Chinese hamster embryos.
The effects of cryopreservation on early embryonic development were investigated in Chinese hamster embryos. Embryos were randomly divided into 3 groups, as follows: the control group, embryos which were simply cultured; the DMSO group, embryos which were exposed to dimethyl sulfoxide (DMSO) and then cultured; the cryopreservation group, embryos which were cryopreserved and then cultured. The percentages of embryos which developed into blastocysts after 40 hours of cultivation were high in all groups. However, there were significant differences in the mean number of blastomeres with lower values after an exposure to DMSO and cryopreservation (73.2 in the control group, 62.0 in the DMSO group, and 40.2 in the cryopreservation group). No significant differences in chromosome abnormality rate were evident and there was no distinct tendency for variation in karyotype among the 3 groups. These results indicate that DMSO adversely affects the division of blastomeres, and that cryopreservation with DMSO as a cryoprotectant might aggravate these adverse effects.
Animals↗
Early development of accelerated graft coronary artery disease: risk factors and course.
OBJECTIVES: This study assessed the time of first appearance of angiographic graft coronary artery disease in relation to clinical and laboratory variables and clinical events in heart transplant recipients. BACKGROUND: Graft coronary artery disease is the main factor limiting long-term survival after heart transplantation, and it is important to understand its natural history. METHODS: One hundred thirty-nine consecutive patients who developed angiographic coronary artery disease after heart transplantation were classified according to early (< or = 2 years) versus late (> 2 years) posttransplantation initial detection of coronary artery disease. These subgroups were analyzed for differences in clinical and laboratory demographics, incidence of progression to ischemic events and incidence of antecedent cytomegalovirus infection. RESULTS: The early-onset group (64 patients) had more rapid progression to ischemic events than the late-onset group (75 patients), with 59% of the late group and only 35% of the early group free from ischemic events by 5 years after initial detection (p = 0.02), but there were no significantly correlated clinical or laboratory predictors of ischemic events. The early group had a significantly higher incidence of antecedent cytomegalovirus infection. CONCLUSIONS: We conclude that 1) accelerated graft coronary artery disease develops at variable times after heart transplantation; 2) the early appearance of graft coronary artery disease may be a marker of intrinsically more aggressive disease; 3) cytomegalovirus infection is associated with earlier onset of graft coronary artery disease. Patients with early development of graft coronary artery disease should potentially be given priority for interventional strategies as they are developed.
Adult↗
Sero-epidemiological investigations on human herpesvirus 6 (HHV-6) infections using a newly developed early antigen assay.
Monoclonal antibodies (MAbs) were developed against immunodominant HHV-6 (GS isolate) late and early proteins. The major late protein was identified as a probable glycoprotein with a molecular weight of approximately 110 kDa (gp 110). Immunoblotting of the early antigen yielded proteins of 41 and 38 kDa (p41/38). The MAb to the early protein reacted with cells infected with 14 different HHV-6 isolates. In contrast, the MAb against the late protein reacted with only 10 of these isolates, indicating that there was strain variation in this glycoprotein. The percentage of antibody-positive sera reactive with gp110 in the ELISA ranged from 56% to 96% among the different serum donor categories. In contrast, only 10-30% of the sera were positive for antibodies to p41/38 with the exception of sera from patients with African Burkitt's lymphoma (ABL) and Hodgkin's disease (HD). These antibody patterns denote the presence of active HHV-6 replication in patients with ABL and HD.
AIDS-Related Complex↗