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At least 325 records · Page 18Linked to original sources
PubMed1999

Muscle growth and development in normal-sex-ratio and all-female diploid and triploid Atlantic salmon.

Muscle development and growth were investigated in diploid populations of normal-sex-ratio and all-female Atlantic salmon (Salmo salar L.) and their triploid counterparts produced by high-pressure treatment. Somites were formed at the rate of 6 h-1 in both diploids and triploids at 6 degrees C. The rostral-to-caudal development of myotubes, myofibrils and acetylcholinesterase staining at the myosepta was slightly more advanced in triploid than in diploid fish, although the differences were smaller than among individual families. The c-met receptor tyrosine kinase was used as a molecular marker for the satellite cells involved in postembryonic muscle growth. Satellite cell nuclei comprised 17.5 % of total myonuclei in smolts and they were 24 % more abundant in diploid than in triploid fish. Cells expressing the myogenic regulatory factor myf-6, a marker of satellite cells committed to differentiation, represented 14.8 % of total myonuclei in diploids and 12.5 % in triploids. At ambient temperatures, the number of white muscle fibres in normal-sex-ratio fish increased more than 30-fold between the alevin and smolt stages, and approximately 3.5-fold further during the first year of seawater growth. The rate of muscle fibre recruitment in seawater stages was significantly greater in diploid than in triploid fish, reaching 1162 fibres day-1 and 608 fibres day-1, respectively, in all-female groups 800 days post-hatching. For 42 cm fork-length fish, there were approximately one-third more muscle fibres per myotome in diploid than in triploid groups, 649 878 and 413 619, respectively, for all-female fish. The probability density function of muscle fibre diameters in each fish was estimated using non-parametric smoothing techniques, and the mean densities for diploids (fD) and triploids (fT) were calculated. The peak fibre diameter was approximately 20 (micro)m in all age classes, irrespective of ploidy. Distinct bimodal distributions of muscle fibre diameter were evident in all groups 775 days and 839 days post-hatching, reflecting seasonal cycles of fibre recruitment. fD and fT were compared using a non-parametric bootstrap technique and the reference band representing the null-hypothesis indicated that there was no difference with ploidy. Reference bands for normal-sex-ratio fish at 315 days and 470 days indicated that diploids had a higher percentage of smaller-diameter fibres and that triploid distributions had a thicker right-hand tail. Similar differences in fD and fT of muscle fibre diameters were found for all-female fish, although the statistical evidence was less strong. Reference bands indicated differences in the middle range of the distributions of muscle fibre diameter in fish 620-775 days post-hatch, with triploids having a thicker right-hand tail. Thus, a lower density of satellite cells was associated with reduced rates of fibre recruitment but a compensatory increase in muscle fibre hypertrophy in triploid compared with diploid fish.

Animals↗
PubMed1984

The fragile X syndrome II: preliminary data on growth and development in males.

Growth data--stature, body weight, occipito-frontal circumference (OFC), ear length and mean testicular volume (MTV)--in 61 males with the fragile X syndrome are presented. Small increases in the mean OFC and ear length and large increases in the MTV were found. The overgrowth of the head was evident in childhood. The characteristic facial appearance was deemed to be present in 60% of the subjects and was recognizable in childhood. Macro-orchidism (MTV of greater than or equal to 30 ml) was present in 80% of the adults but none of the children. Five subjects had a cleft palate, 11 serious eye disorders (3 with congenital nystagmus), and 4 had torticollis and/or kyphosis. Limited information on development suggested that mental retardation was present from early life and was not progressive. Although 3 subjects were autistic (2 with self abuse) most were pleasant, even tempered and cooperative men and boys.

Abnormalities, Multiple↗
PubMed2005

14-3-3 protein signaling in development and growth factor responses.

Tyrosine and serine phosphorylation are central to cellular signaling in growth and development. 14-3-3 proteins function as dimeric phosphoserine-binding proteins with documented interactions throughout the eukaryotic proteome and are highly conserved in both the animal and plant kingdoms. Binding of 14-3-3 to a client protein can have a range of context-dependent effects, including conformational change, enzyme inhibition, a shielding effect, re-localization, and bridging between two molecules. Proteome-based strategies utilizing mass spectrometry have revealed an unprecedented central stage for 14-3-3 in signal transduction with interacting partners composing at least 0.6% of the cellular proteome. 14-3-3 has been shown to bind to the human GM-CSF, IL-3, and IL-5 receptors and is required for the transmission of cell survival. 14-3-3 is involved in survival-specific signals, acting not only at the receptor level but also at critical steps downstream of the receptor. This phosphoserine-mediated pathway works independently of tyrosine kinases, highlighting an alternative mechanism of signaling for this receptor family. Other growth factor receptors and their adaptors are also being shown to associate with 14-3-3 and/or have putative 14-3-3 interaction sequences, such as the prolactin receptor, IGF-1 receptor, and some G-protein coupled receptors. 14-3-3 proteins are remarkably conserved through eukaryotic organisms and in Drosophila are required for photoreceptor development, learning, timing of cell cycles, and maintenance of cellular polarity. These findings are elevating our initial description of biochemical interactions to a better understanding of 14-3-3 function at the level of the whole organism. Further study should explore the integration of phosphoserine and phosphotyrosine signaling by 14-3-3 proteins and the role of isoform-specific functions in higher organisms. The prevalence of functional 14-3-3 binding sites throughout the proteome, and especially among growth factor receptors and signaling molecules, reflects a global role for 14-3-3 in multiple cellular decision making.

14-3-3 Proteins↗
PubMed2006

Allometric studies on growth and development of the human placenta: growth of tissue compartments and diffusive conductances in relation to placental volume and fetal mass.

Correlations between placental size and fetal mass during gestation fail to account for changes in composition that accompany placental growth and maturation. This study uses stereological data on the sizes of different tissue compartments in human placentas from 10 weeks of gestation to term and relates them to placental volume and to fetal mass by means of allometric analysis. In addition, tissue dimensions are used to calculate a physiological transport measure (diffusive conductance) for the villous membrane. Histological sections randomly sampled from placentas and analysed stereologically provided estimates of structural quantities (volumes, exchange surface areas, lengths, numbers of nuclei, diffusion distances). These data were combined with a physicochemical quantity (Krogh's diffusion coefficient) in order to estimate oxygen diffusive conductances for the villous membrane and its two components (trophoblast and stroma). Allometric relationships between these quantities and placental volume or fetal mass were obtained by linear regression analyses after log-transformation. Placental tissues had different growth trajectories: most grew more rapidly than placental volume and all grew more slowly than fetal mass. Diffusion distances were inversely related to placental and fetal size. Differential growth impacted on diffusive conductances, which, again, did not improve commensurately with placental volume but did match exactly growth of the fetus. Findings show that successful integration between supply and demand can be achieved by differential tissue growth. Allometric analysis of results from recent studies on the murine placenta suggest further that diffusive conductances may also be matched to fetal mass during gestation and to fetal mass at term across species.

Biological Transport↗
PubMed2000

Development and growth of several strains of Arabidopsis seedlings in microgravity.

Growth and development of dark-grown Arabidopsis thaliana seedlings were studied in microgravity during space shuttle mission STS-84. The major purpose of this project was to determine if there were developmental differences among the four ecotypes studied--Wassilewskija (Ws), Columbia (Col), Landsberg erecta (Ler), and C24--and to evaluate whether particular ecotypes are better suited for spaceflight experimentation compared with others. A secondary goal was to study the growth of three starch-deficient strains of Arabidopsis by extending the observations made in a previously published report. For all strains, seed germination was not affected by microgravity, but seedlings were smaller in the spaceflight samples compared with the ground controls. The starch-deficient strains continued to exhibit vigorous growth until the termination of the experiment at 121 h after imbibition of seeds. However, ethylene effects, i.e., reduced growth and exaggerated hypocotyl hooks, were observed in all strains studied. Nevertheless, the Ler and C24 ecotypes seem to be more suitable for spaceflight research, compared with the other two ecotypes, based on measurements of their relative and absolute growth. This type of information should aid in the design of plant experiments for the International Space Station.

Arabidopsis↗
PubMed1997

Essential role of the tyrosine kinase substrate phospholipase C-gamma1 in mammalian growth and development.

The activation of many tyrosine kinases leads to the phosphorylation and activation of phospholipase C-gamma1 (PLC-gamma1). To examine the biological function of this protein, homologous recombination has been used to selectively disrupt the Plcg1 gene in mice. Homozygous disruption of Plcg1 results in embryonic lethality at approximately embryonic day (E) 9.0. Histological analysis indicates that Plcg1 (-/-) embryos appear normal at E 8.5 but fail to continue normal development and growth beyond E 8.5-E9.0. These results clearly demonstrate that PLC-gamma1 with, by inference, its capacity to mobilize second messenger molecules is an essential signal transducing molecule whose absence is not compensated by other signaling pathways or other genes encoding PLC isozymes.

Animals↗
PubMed1994

Anterior pituitary and adrenal cortical hormones accelerate or inhibit tadpole hindlimb growth and development depending on stage of spontaneous development or thyroxine concentration in induced metamorphosis.

The effect of prolactin, growth hormone, and various adrenal corticoids on hindlimb growth, development, and differentiation was studied in Rana pipiens larvae. Experiments were performed at different stages of spontaneous development and during metamorphosis induced in premetamorphic tadpoles by various concentrations of exogenous T4. Prolactin at 10 micrograms/day inhibited the limb at spontaneous premetamorphosis, had no effect at prometamorphosis or when administered with 3.8 nM T4, and synergized with T4 at 63 nM T4 and above. Growth hormone (10 or 20 micrograms/day) promoted limb growth and development during premetamorphosis but had no effect on spontaneous or induced metamorphosis thereafter, nor did it stimulate limb epidermal differentiation. The adrenal corticoids inhibited limb growth and epidermal cell proliferation during pre- and prometamorphosis but had no effect on limb morphogenesis or differentiation. The depressive effect of corticoids during spontaneous metamorphosis is at least partly through thyroid inhibition since hydrocortisone significantly reduced follicle cell height, lumen diameter, and cell proliferation in the thyroid. During induced metamorphosis, steroids (0.29 microM), especially corticosterone and aldosterone, antagonized the effect of 0.38 to 1.2 nM T4 on the limb. All steroids except deoxycorticosterone synergized with 3.8 nM T4, and at 31 nM T4, approximating the climax level with permeability factors taken into account, all corticoids synergized with T4 to promote limb growth and development. Aldosterone antagonized T4 at a higher T4 level than the other corticoids. The effect of all steroids except corticosterone was also corticoid dose-dependent. The results show the importance of the T4 concentrations in interactions of T4 with other hormones and suggest a scheme for hormonal control of limb growth and morphogenesis during metamorphosis. During premetamorphosis growth hormone synergizes with low endogenous T4 to promote initial limb growth and development while prolactin opposes this action. During prometamorphosis, as growth hormone and prolactin become ineffective corticosteroids begin to synergize with the rising level of endogenous T4. At climax, prolactin also augments the action of T4 to bring about rapid hindlimb growth.

Adrenal Cortex Hormones↗
PubMed1988

Prenatal and postnatal growth and development of the foot and ankle.

The intent of this article is to present a detailed overview of the normal prenatal and postnatal development and growth of the lower limb with special emphasis on the ankle-foot complex. The effects of physiologic load and its components of duration, timing, and direction are discussed. The results of abnormal amount, timing, duration, or direction of load on the prenatal and postnatal human are discussed with examples of foot deformity provided for clarification. Principles of therapeutic force application for the reversal of deformity are formulated.

Ankle↗
PubMedDate not supplied

In vitro effects of recombinant human megakaryocyte growth and development factor on primary human tumour colony growth.

A study was made of the in vitro effects of recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on breast, prostate, cervix and colon cancers. Tumour growth was assessed using a soft agar clonogenic assay. Stimulation of megakaryocyte numbers was seen in liquid culture following 10 ng/ml PEG-rHuMGDF. The same concentration led to no significant difference in colony-forming efficiencies for 22 of 25 tumour samples. A significant reduction in colony-forming efficiencies was seen for the remaining 3 specimens. These results suggest that PEG-rHuMGDF will not stimulate tumour growth in vivo.

Breast Neoplasms↗
PubMed1986

Growth and development of intraocular fetal cortex cerebri grafts in rats of different ages.

Cortex cerebri pieces from fetal donors were homologously and bilaterally grafted to the anterior chamber of the eye of 1.5-, 3.0- and 7.5-month-old rats. Repeated stereoscopic in vivo measurements revealed that the grafts in the young group grew to a size twice as large as those in the older two groups. The degree of gliosis was studied immunohistochemically using antibodies against glial fibrillary acidic protein. Both grafts to young and to older hosts were clearly gliotic as compared to normal cerebral cortex. However, the gliosis was significantly more pronounced in grafts to 3.0- and 7.5-month-old hosts as compared to grafts to 1.5-month-old hosts. The vascular component was evaluated using antibodies against laminin. We found laminin immunofluorescence to be an excellent marker of brain tissue vascularization, particularly at the capillary level, revealing the entire capillary tree and endothelial budding. The density of the vascular plexus and the average thickness of the capillaries of cortex cerebri grafted to the youngest recipients was remarkably similar to normal cerebral cortex. In marked contrast, grafts to the older hosts had a clearly pathological vascular network characterized by few, thick-walled blood vessels and very few normal-looking capillaries. We conclude that host age factors profoundly influence development and growth of intraocular brain tissue grafts.

Animals↗
PubMed1985

Cholera toxin treatment increases in vivo growth and development of the mouse mammary gland.

Daily sc injections of cholera toxin (CT; 0.1 micrograms/day), a stimulator of adenylate cyclase activity, into intact female BALB/c mice for 20 days significantly (P less than 0.05) increased mammary gland development scores from 2.0 +/- 0.1 in controls to 3.6 +/- 0.2 in CT-treated mice. Concurrent administration of 17 beta-estradiol (E; 1.0 microgram/day) and progesterone (P; 1.0 mg/day) resulted in development scores of 4.1 +/- 0.1 and 5.2 +/- 0.1 in E/P and E/P + CT treatment groups, respectively (P less than 0.05). If mice were ovariectomized before CT injection, the response to CT alone was abolished (development scores of 2.0 +/- 0.1 and 1.9 +/- 0.1 in controls and CT-treated mice, respectively). However, E/P restored the response to CT (scores of 3.2 +/- 0.2 for E/P and 4.0 +/- 0.1 for E/P + CT; P less than 0.05) in ovariectomized mice. CT significantly (P less than 0.05) increased mammary dry fat-free tissue weight from 2.89 +/- 0.41 mg (controls) to 3.78 +/- 0.37 mg (CT-treated) and from 4.03 +/- 0.59 mg (E/P-treated) to 5.42 +/- 0.91 mg (E/P + CT). Similarly, CT treatment increased mammary DNA from 138.7 +/- 11.7 micrograms (controls) to 162.8 +/- 14.4 micrograms (CT) and from 178.5 +/- 12.6 to 233.9 +/- 28.0 micrograms in the presence of E/P (P less than 0.05). Furthermore, CT was found to be mammogenic in hypophysectomized mice treated with E (1.0 microgram/day), P (1.0 mg/day), deoxycorticosterone acetate (0.5 mg/day), T4 (0.2 microgram/ml drinking water), and glucose (50 mg/ml drinking water), i.e. mammary gland development scores were 1.5 +/- 0.1 in mice treated with the above regimen and 3.1 +/- 0.1 in mice treated with the above regimen plus CT for 14 days (P less than 0.05). These results provide clear evidence, heretofore unreported, that systemic CT treatment increases mammary gland development and growth in female mice. The mammogenic effects of CT are observed in intact female mice with or without exogenous E/P, in ovariectomized mice treated with E/P, and in hypophysectomized mice treated with E/P, deoxycortisone acetate, and T4.

Adipose Tissue↗
PubMedDate not supplied

Chemopreventive activity of a C-glucuronide analog of N-(4-hydroxyphenyl) retinamide-O-glucuronide against mammary tumor development and growth.

The long term chemopreventive effects of the N-(4-hydroxyphenyl) retinamide-O-glucuronide (4-HPROG), and its stable C-linked benzyl glucuronide analog, retinamidobenzyl glucuronide (4-HPRCG) on the growth and development of 7,12-dimethylbenz[a]anthracene-induced mammary tumors were compared. The retinamidobenzyl glucuronide is stable toward acid hydrolysis and resists the actions of beta-glucuronidase. The results indicate that the C-linked glucuronide analog, 4-HPRCG has a greater chemopreventive potency than an equimolar concentration of 4-HPROG. Tumor latency was 15% longer in rats fed 2 mmol/kg diet of 4-HPRCG as compared to 4-HPROG. At 80 days post DMBA-intubation, tumor incidence was 57% and 27% in the 4-HPROG and 4-HPRCG treated rats, respectively. Tumor multiplicity was also markedly decreased in the 4-HPRCG treated rats. At 80 days post DMBA intubation the control rats had an average of 1.43 tumors/rat compared to 0.71 and 0.36 tumors/rat in the 4-HPROG and 4-HPRCG respectively. The higher potency and low toxicity of 4-HPRCG suggest that this stable analog may have an in vivo chemopreventive advantage over its analog, 4-HPROG. The results also demonstrated that these glucuronide analogs do not bind effectively in vitro either to the nuclear retinoid receptors or to the cellular retinoid binding proteins. Regardless of the mode of action of these retinoids, they are clearly effective chemopreventive agents.

9,10-Dimethyl-1,2-benzanthracene↗