SEARCH · PubMed Health

Results for “Developmental stage”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources

PubMed1981

Developmental stages of genome elimination resulting in transmission ratio distortion of the T-007 male recombination (MR) chromosome of Drosophila melanogaster.

T-007 is a Male Recombination (MR) second chromosome that induces transmission ratio distortion (at its own expense) when heterozygous with many laboratory marker chromosomes. The developmental timing of elimination of T-007 chromosomes has been investigated. About 21% of the T-007 chromosomes expected to be recovered among the progeny of heterozygous T-007 males are lost at some point between fertilization and eclosion (representing 29% of the total distortion observed in young males). Another 52% of the expected number of T-007 chromosomes are lost as a result of spermatid abortion during spermiogenesis (representing 71% of the total distortion). Abnormalities in both the number of spermatids per bundle and the structure of spermatid tails are seen at the earliest stages of spermiogenesis in T-007 males.

Animals↗

PubMed1990

Comparative study of acetaminophen disposition in sheep at three developmental stages: the fetal, neonatal and adult periods.

The disposition of acetaminophen was studied in adult nonpregnant ewes, neonatal lambs, pregnant ewes and their fetal lambs following single intravenous bolus doses. Comparisons of the pharmacokinetic parameters of acetaminophen were made between sheep at different developmental periods to examine the developmental alteration in the physiological and biochemical processes governing drug disposition. The four groups of animals exhibited distinct and significant differences in the total clearance and metabolic clearances of acetaminophen and the renal clearances of the glucuronide and sulfate conjugates. Placental transfer of acetaminophen from fetus to mother serves as the dominant route of fetal removal or clearance of the drug.

Acetaminophen↗

PubMed1987

Developmental-stage-specific expression of the hsp70 gene family during differentiation of the mammalian male germ line.

Mouse somatic tissues contain low levels of transcripts homologous to the heat shock-inducible and cognate members of the heat shock protein 70 (hsp70) gene family. An abundant, unique sized hsp70 mRNA of 2.7 kilobases (kb) is present in testes in the absence of exogenous stress. Its expression is restricted to germ cells and is developmentally regulated. The 2.7-kb transcript first appears during the haploid phase of spermatogenesis and is stable throughout the morphogenic stages of spermiogenesis. A 2.7-kb hsp70 mRNA is present in rat and human testes. These observations suggest that a member of the hsp70 gene family plays a role in the development of the mammalian male germ cell lineage.

Age Factors↗

PubMed1990

Expression of LPG and GP63 by different developmental stages of Leishmania major in the sandfly Phlebotomus papatasi.

Development and forward migration of Leishmania parasites in the sandfly gut is accompanied by morphological transformation to highly motile, non-dividing 'metacyclic' forms. Previous studies in vitro have demonstrated that this metacyclogenesis is associated with developmentally regulated changes in expression of two major surface glycoconjugates of Leishmania, the lipophosphoglycan (LPG) and the glycoprotein protease GP63. Studies presented here are the first to examine in situ the changes in expression of these two important surface molecules which occur during amastigote-initiated development of L. major in its natural vector Phlebotomus papatasi. Immunocytochemical analysis using a GP63-specific monoclonal (3.8), and others recognizing metacyclic-specific (3F12) and common (WIC79.3) epitopes of LPG on logarithmic and metacyclic promastigotes, demonstrates: (1) clear expression of LPG and GP63 from 2 and 7 days post-bloodfeeding, respectively; (2) developmental modification of the LPG molecule as parasites undergo forward migration and morphological changes associated with metacyclogenesis; and (3) striking deposition of large amounts of parasite-free excreted LPG on/in the epithelial cells of the gut wall.

Animals↗

PubMed1990

Developmental stages of cucumber seedlings: kinetics of chlorophyll accumulation and other growth parameters.

The changes in morphology during dark germination and subsequent growth of cucumber (Cucumis sativus) seedlings in the light go through three different phases described as latent, active, and steady-state. This pattern is consistently observed for several related developmental processes. The latent period lasts about 2 days following water imbibition after which the following capabilities appear in concert: (a) root and stem elongation, (b) pigment synthesis including protochlorophyll, chlorophyll, carotenoid, and phytochrome, (c) synthesis of ribulose-1,5-bisphosphate carboxylase/oxygenase, and (d) enhancement of greening by excision. Following the active phase, which lasts for another 2 to 3 days, these processes slow to a steady-state. Inhibition of chlorphyll accumulation by SO(2) was only observed for seedlings in the steady-state phase.

Journal Article↗

PubMed2001

CD34 expression on long-term repopulating hematopoietic stem cells changes during developmental stages.

The CD34 antigen serves as an important marker for primitive hematopoietic cells in therapeutic transplantation of hematopoietic stem cells (HSC) and gene therapy, but it has remained an open question as to whether or not most HSC express CD34. Using a competitive long-term reconstitution assay, the results of this study confirm developmental changes in CD34 expression on murine HSC. In fetuses and neonates, CD34 was expressed on Lin(-)c-Kit(+) long-term repopulating HSC of bone marrow (BM), liver, and spleen. However, CD34 expression on HSC decreased with aging, and in mice older than 10 weeks, HSC were most enriched in the Lin(-)c-Kit(+)CD34(-) marrow cell fraction. A second transplantation was performed from primary recipients who were transplanted with neonatal Lin(-)c-Kit(+) CD34(high) HSC marrow. Although donor-type HSC resided in CD34-expressing cell fraction in BM cells of the first recipients 4 weeks after the first transplantation, the stem cell activity had shifted to Lin(-)c-Kit(+)CD34(-) cells after 16 weeks, indicating that adult Lin(-)c-Kit(+)CD34(-) HSC are the progeny of neonatal CD34-expresssing HSC. Assays for colony-forming cells showed that hematopoietic progenitor cells, unlike HSC, continue to express CD34 throughout murine development. The present findings are important because the clinical application of HSC can be extended, in particular as related to CD34-enriched HSC and umbilical cord blood HSC.

Age Factors↗

PubMed2003

Variation of glucosinolate accumulation among different organs and developmental stages of Arabidopsis thaliana.

The glucosinolate content of various organs of the model plant Arabidopsis thaliana (L.) Heynh., Columbia (Col-0) ecotype, was analyzed at different stages during its life cycle. Significant differences were noted among organs in both glucosinolate concentration and composition. Dormant and germinating seeds had the highest concentration (2.5-3.3% by dry weight), followed by inflorescences, siliques (fruits), leaves and roots. While aliphatic glucosinolates predominated in most organs, indole glucosinolates made up nearly half of the total composition in roots and late-stage rosette leaves. Seeds had a very distinctive glucosinolate composition. They possessed much higher concentrations of several types of aliphatic glucosinolates than other organs, including methylthioalkyl and, hydroxyalkyl glucosinolates and compounds with benzoate esters than other organs. From a developmental perspective, older leaves had lower glucosinolate concentrations than younger leaves, but this was not due to decreasing concentrations in individual leaves with age (glucosinolate concentration was stable during leaf expansion). Rather, leaves initiated earlier in development simply had much lower rates of glucosinolate accumulation per dry weight gain throughout their lifetimes. During seed germination and leaf senescence, there were significant declines in glucosinolate concentration. The physiological and ecological significance of these findings is briefly discussed.

Arabidopsis↗

PubMed2006

A genome scan for quantitative trait loci associated with body weight at different developmental stages in chickens.

A genome scan to detect quantitative trait loci (QTL) affecting body weight in chickens was conducted on 238 F(2) chickens from a reciprocal cross of Silky Fowl and White Plymouth Rock using 125 microsatellite markers covering 23 autosomes and the Z chromosome. Two types of QTL were considered: static QTL (SQ) and developmental QTL (DQ). Static QTL affected the body weight from hatch to time t, and DQ affected the body weight from time t-1 to time t. Six SQ and nine DQ were detected. Of these QTL, four reached a genome-wide significance of 5% or better, with SQ1 and DQ1 being the most significant QTL. Static QTL1 was on chromosome 1 between GCT0006 and MCW0106 and explained 4.05-9.80% of the phenotypic variation in body weights from 3 to 12 weeks of age. At 9, 10 and 11 weeks, the genome-wide significance thresholds of SQ1 were <1%. Developmental QTL1 was located on chromosome 1 between MCW0168 and GCT0006, and explained 2.75% of the phenotypic variation for body weight from week 7 to 8 with a genome-wide significance level <1%. The results suggest that body weight from hatch to time t and developmental growth from time t-1 to time t may involve two different sets of genes or gene actions.

Animals↗

PubMed1990

The urea-soluble low molecular weight cuticle proteins from the different developmental stages of Dacus oleae.

The cuticle proteins of the insect Dacus oleae have been isolated by extraction with a solution of 7 M urea. The affinity properties of cuticle proteins, isolated from the third instar larvae (L3DCPs 1-7), to chitin have been studied. Purified cuticle antigens were polymerized by glutaraldehyde and used for raising antibodies. The developmental appearance of the cuticle proteins has been studied by two-dimensional electrophoresis.

Animals↗

PubMed1998

Developmental stages and spiritual coping responses among economically impoverished women living with HIV disease.

Identifies environmental markers, situational appraisals, perceived ability to mediate situations and outcomes, primary coping strategies, and purposes served by religion and spirituality in 10 HIV-positive women recruited from a regional health care clinic. Findings indicated that the women experienced a disintegration of family during their early developmental years, yielding feelings of hopelessness and isolation; that their sexual development was marked by rape and incest, and their early adulthood was characterized by failed relationships, pregnancies, drugs, and alcohol. Reports that the women's religious influences were predominantly maternal and provided a model for intercessory prayer. Notes that prior to their diagnosis of HIV, participants described their coping as escapist, while after diagnosis they believed there was a divine intercession renewing their spiritual growth and connectedness with others. Reports that the women's personal spirituality was greatly influenced by prayer, television ministries, and reading the Bible. Suggests the interventions that actively recruit women into social support services, health care systems, and faith congregations are needed and that television ministries may serve as access points for connecting women with necessary services.

Adaptation, Psychological↗

PubMed1999

Role of insulin-like growth factor binding proteins in limitation of IGF-I degradation into the N-methyl-D-aspartate receptor antagonist GPE: evidence from gonadotrophin-releasing hormone secretion in vitro at two developmental stages.

We showed previously that insulin-like growth factor-I (IGF-I) could inhibit the secretion of gonadotrophin-releasing hormone (GnRH) evoked in vitro by N-methyl-D-aspartate (NMDA) or veratridine depolarization. Such an IGF-I effect appeared to be mediated by its physiological breakdown product, the N-terminal tripeptide GPE. That effect was developmentally regulated since IGF-I could inhibit GnRH secretion from hypothalamic explants of 50-day-old adult rats but not from immature 15-day-old explants. We hypothesized that the IGF-binding proteins (BPs) could limit the peptide availability to endopeptidases and account for the absent IGF-I effects at 15 days. In this paper, we show that the inhibition of GnRH secretion by 10(-10) M of IGF-I at 50 days is prevented in a dose-dependent manner by 0.3 to 3 nM of IGF-BP2 as well as IGF-BP3. The inhibition caused by 10(-10) M of GPE is not affected under similar conditions. Using explants obtained at 15 days, a significant inhibition of GnRH secretion can be obtained by 10(-10) M of IGF-I in the presence of an anti IGF-BP2 antiserum used at 1:3000 and 1:1000 concentrations. These data indicate that in the immature rat brain, the IGF-BPs could act as modulators of IGF-I degradation into its subproduct GPE, a possible endogenous antagonist at NMDA receptors.

Animals↗

PubMed1992

Developmental stage- and tissue-specific expression of shibire, a Drosophila gene involved in endocytosis.

Dynamin, a microtubule-activated GTPase, has recently been identified as the product of the shibire gene in Drosophila. shi(ts) mutants are defective in synaptic vesicle recycling, which leads to rapid and reversible temperature-sensitive paralysis. In the present study, results from RNase protection assays and analysis of cDNA clones define a complex pattern of developmental- and tissue-specific alternative splicing at two sites within the coding region. This analysis is also supported by western blot analysis with two polyclonal antibodies. In situ hybridization data revealed a high concentration of shi transcripts in the central and peripheral nervous system throughout neuronal development. Other than the nervous system, shi transcripts are also expressed at a high level in early embryos, larval imaginal discs, and male and female gonads. These data provide a basis for interpreting the wide range of phenotypic effects of shi mutations in terms of the putative membrane-sorting properties of dynamin and for further functional study of different dynamin isoforms.

Amino Acid Sequence↗

PubMedDate not supplied

Children's susceptibility to chemicals: a review by developmental stage.

Concerns about adequate protection of children's health from chemicals in the environment have created a need for research to identify how children's risks differ from adults'. A systematic review of factors that affect child sensitivity throughout development may be useful for research and practice in this area. We summarized available literature and other peer-reviewed information on factors that affect pharmacokinetics and exposure in an age-based developmental framework. Biological processes related to chemical absorption (gastrointestinal, dermal, and pulmonary), distribution, metabolism, and excretion were considered, along with reference to behaviors and other factors associated with child-specific exposures. The available information was summarized in a timeline of maturation for biological processes. It indicates variability in the duration and timing of maturation for each biological function. Possible implications for understanding pediatric sensitivity to environmental chemicals are discussed in light of factors affecting exposure through development. Themes that emerge from the evidence are presented as hypothesis-generating conclusions. This approach may be useful for evaluating developmental trends of susceptibility, and for identifying time periods and/or chemical classes of particular concern and thus important to consider in risk assessment.

Adolescent↗

PubMed2003

Regulation of the nitrate transporter gene AtNRT2.1 in Arabidopsis thaliana: responses to nitrate, amino acids and developmental stage.

The NR72.1 gene codes for a high-affinity nitrate transporter in Arabidopsis thaliana. To examine the regulation of NRT2.1 gene expression, we used a promoter-beta-glucuronidase (GUS) fusion and found that the NRT2.1 promoter directs expression to the epidermal, cortical and endodermal cell layers of mature root parts. The gene appeared to be expressed essentially in roots, but was also present in the leaf hydathodes. Investigation of NRT2.1 expression pattern during the plant developmental cycle showed that it increased rapidly during early vegetative growth, peaked prior to floral stem emergence, and decreased to very low levels in flowering and silique-bearing plants. Experiments with various nitrogen supply regimes demonstrated the induction of NRT2.1 expression by nitrate and repression by amino acids. Amino acid analysis showed that this repression was specifically related to increased internal glutamine, suggesting a role for this particular amino acid in nitrogen signalling responsible for nitrate uptake regulation. Taken together, our results support the hypothesis that the NRT2.1 gene codes for a major component of the inducible high-affinity transport system for nitrate, which is spatially and developmentally controlled at the transcriptional level. Surprisingly, NRT2.1 was not expressed in younger root parts, although a similar rate of nitrate influx was observed in both young and old root samples. This lack of correlation between nitrate influx and NRT2.1 expression suggests that another high-affinity nitrate transporter operates in root tips.

Amino Acids↗

PubMed1993

Effect of caffeine and high potassium on normal and dystrophic mouse EDL muscles at various developmental stages.

EDL muscles from normal and dystrophic (dy2j) mice of various ages were examined. Muscles were divided into three groups according to age: 7 to 14 days postnatal, 16 to 21 days postnatal, and 6 months old, to assess age and/or phenotype related differences in the muscle response to caffeine or high K+. The response of normal muscles to caffeine decreased with age and reached adult characteristics between the second and third week of postnatal life. Their response to high K+ also changed during postnatal development; specifically, the time taken to recover to 50% pretest twitch tension decreased with age, probably reflecting developmental changes in Cl- conductance. Up to 21 days of age, the sensitivity of dystrophic muscles to both caffeine and high K+ was essentially similar to normal, while marked differences were observed in the adult. Taken altogether, our results suggest that while the maturation of a number of systems might be delayed in dystrophic muscles at preclinical stages of the disease, their e-c coupling and SR function (Ca2+ release and reuptake) appear to be quite normal. Our results further suggest that the "abnormal" responses of dystrophic muscles at more advanced stages of the disease, when challenged by drugs acting on either of these systems, may be explained in terms of changes in muscle fiber type proportions.

Aging↗

PubMed2002

Predictor variables by developmental stages: a center for substance abuse prevention multisite study.

Five articles present the results obtained in a multisite study funded by the Center for Substance Abuse Prevention (CSAP). The overarching goal of this effort was to determine the efficacy of reducing severity of factors during childhood that are known to magnify the risk for substance abuse (SA) in adolescence. The factors targeted for preventive intervention were Behavior Self-Regulation, Parental Involvement, School Bonding, and Social Competence. Conceptualizing SA within a developmental framework, the findings indicate that prevention directed at youth between 3-14 years of age has a significant positive impact on attenuating intermediary factors predisposing to SA. In this introduction, both the theoretical framework and rationale guiding this cooperative agreement and the key findings are described.

Achievement↗

PubMed2005

Basal immunoglobulin signaling actively maintains developmental stage in immature B cells.

In developing B lymphocytes, a successful V(D)J heavy chain (HC) immunoglobulin (Ig) rearrangement establishes HC allelic exclusion and signals pro-B cells to advance in development to the pre-B stage. A subsequent functional light chain (LC) rearrangement then results in the surface expression of IgM at the immature B cell stage. Here we show that interruption of basal IgM signaling in immature B cells, either by the inducible deletion of surface Ig via Cre-mediated excision or by incubating cells with the tyrosine kinase inhibitor herbimycin A or the phosphatidylinositol 3-kinase inhibitor wortmannin, led to a striking "back-differentiation" of cells to an earlier stage in B cell development, characterized by the expression of pro-B cell genes. Cells undergoing this reversal in development also showed evidence of new LC gene rearrangements, suggesting an important role for basal Ig signaling in the maintenance of LC allelic exclusion. These studies identify a previously unappreciated level of plasticity in the B cell developmental program, and have important implications for our understanding of central tolerance mechanisms.

Androstadienes↗

PubMed1999

Primary socialization theory. Developmental stages, spirituality, government institutions, sensation seeking, and theoretical implications. V.

This fifth and final paper in the series on primary socialization theory includes discussion of issues raised by participants in a forum on the theory. The theory states that drug use and deviant behaviors occur as an outcome of bonding with primary socialization sources and the transmission of norms through those sources. Personal traits and secondary socialization sources influence drug use and deviance indirectly and through their effects on the primary socialization process. Developmentally, the only primary socialization source for the preschool child is the family. In early grade school years, the primary socialization sources are the family and school. Peer clusters emerge as a primary socialization source later, with their greatest effect occurring during adolescence. Adults have varied primary socialization patterns. Levels of ego development among adults may alter the primary socialization process. Spirituality is defined, and its influence on drug use is discussed. Government institutions, such as the criminal justice system, welfare, and child protective services, are now included among secondary socialization sources. The fact that the general theory of primary socialization is not ethnocentric or temporocentric is discussed. Implications of the theory for understanding existing or potential risk and protective factors for deviance, and for improving the effectiveness of prevention and treatment are discussed. [Translations are provided in the International Abstracts Section of this issue.]

Adolescent↗