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Growth And Development (growth + and_development)
Kinds of Growth And Development Selected AbstractsGrowth and Development with Special Reference to Developing Countries by A. P. Thirlwall (Palgrave Macmillan: London, 2003, 7th edn, pp. xxviii + 816.JOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 8 20032nd edn, Macroeconomics for Developing Countries by Raghbendra Jha (Routledge: London, pp. xi + 496). No abstract is available for this article. [source] Craniofacial skeletal deviations following in utero exposure to the anticonvulsant phenytoin: monotherapy and polytherapyORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 1 2003HI Orup Jr Structured Abstract Authors , Orup Jr HI, Holmes LB, Keith DA, Coull BA. Objective , To identify and quantify the craniofacial effects from prenatal exposure to phenytoin monotherapy and polytherapy using cephalometric, hand-wrist, and panoramic radiographs and to determine if such deviations persist with age. Design , Craniofacial structures of 28 anticonvulsant-exposed individuals were evaluated using 20 landmarks in lateral cephalometric radiographs and 19 landmarks in frontal cephalometric radiographs. Skeletal maturity was assessed using hand-wrist radiographs. Dental maturity and the presence of dental anomalies were evaluated using panoramic radiographs. Eleven individuals were re-evaluated 7 years later, on average, to determine the persistence of any measured deviations. Setting and Sample Population , Department of Growth and Development, Harvard School of Dental Medicine and Massachusetts General Hospital. Patients were recruited from several sources. Outcome Measure , The evaluated dimensions included linear, angular, and proportional measures. Results , The most common deviations were decreased height and length of the maxilla, decreased length of the posterior cranial base, length of the mandible, cranial width and level of the cribriform plate, and a decrease in the Wits Appraisal assessment. The deviations were more significant in the polytherapy-exposed individuals than in the monotherapy-exposed individuals. These deviations, especially in the maxilla, persisted with age as revealed in a re-evaluation of 11 individuals. Conclusion , The craniofacial skeletal findings among individuals exposed in utero to phenytoin monotherapy or phenytoin polytherapy, when considered in aggregate, suggest a mild pattern of maxillary hypoplasia that becomes more pronounced with age. [source] Growth and Development of a Body of Knowledge: 16 Years of New Product Development Research, 1989,2004,THE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 3 2008Albert L. Page In this study, a content analysis was performed on 815 articles focused on new product development (NPD) published in 10 selected leading marketing, management, NPD, and research and development (R&D) journals from 1989 to 2004. Journals selected were a combination of leading journals in the discipline and publications that included NPD articles. NPD articles were classified by a series of key attributes including methodology employed, domains of knowledge utilized, and broad topics explored. The resulting data were then studied to discern trends over time or common characteristics within domains, methodologies, or journals. The study of NPD has grown since the Journal of Product Innovation Management (JPIM) was launched in 1984. This study shows strong growth in the number of articles on NPD in each category of journal selected. The research in the articles has changed: The early focus on a few selected success factors or a staged development process has evolved and broadened over the 16-year period. More variables and more sophisticated models are being studied in NPD articles. The study found a continuing evolution in research topics and increased sophistication in quantitative techniques over the 16-year period. Overall this review of the NPD literature uncovers encouraging signs of a maturing discipline. However, there are concerns about continuing issues in methodology, insufficient study of service innovation, and continued focus on process characteristics instead of other antecedents of NPD success. The service sector seems to be understudied, even as the reality of a service economy is generally acknowledged. The call in a recent meta-analysis to focus more on market and product characteristics and less on process characteristics has not yet been heeded, even by marketing researchers. [source] Assessment of Bone Mineralization Following Renal Transplantation in Children: Limitations of DXA and the Confounding Effects of Delayed Growth and DevelopmentAMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2001Mary B. Leonard Pediatric renal transplantation recipients have numerous risk factors for decreased bone mass, including the underlying renal disease, nutritional deficits, decreased physical activity, inflammation and exposure to steroid therapy. The assessment of bone mineralization in children following renal transplantation is fraught with difficulty. Dual energy x-ray absorptiometry (DXA) is the most commonly employed tool to assess bone mineralization. However, DXA has important limitations in children and in individuals with renal disease. This brief review will examine the expected gains in bone size and bone mass during growth and the mechanisms by which renal failure and steroid therapy interrupt these process. In addition, the limitations of DXA for detecting impaired bone mineralization in children with renal disease are reviewed and alternative approaches explored. [source] Effects of iodine supplementation during pregnancy on child growth and development at school ageDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 2 2002Karen J O'Donnell MEd PhD Growth and development of 207 children (49% males; mean age 5.4 years [SD 0.2], range 4 to 7.3 years whose mothers received iodine during pregnancy, and children who received iodine first in their 2nd year, were examined in 1996; 192 children(49% males; mean age 6.5 years[SD 0.2], range 5.8 to 6.9 years) whose mothers received iodine while pregnant were seen in 1998. Children were from the southern part of China's Xinjiang Province which has the lowest levels of iodine in water and soil ever recorded. Head circumference but not height was improved for those who received iodine during pregnancy (compared with those receiving iodine at age 2) and for those supplemented before the end of the 2nd trimester (relative to those supplemented during the 3rd trimester). Iodine before the 3rd trimester predicted higher psychomotor test scores for children relative to those provided iodine later in pregnancy or at 2 years. Results from the test for cognitive development resulted in trend only differences between those children supplemented during pregnancy versus later. The results address the question of when maternal iodine supplements should begin in public health programs world wide. Findings may be relevant to the treatment of maternal and newborn thyroid deficiency in industrialized countries, particularly for those infants delivered before the end of the second trimester. [source] Development, growth, and egg production of Ageneotettix deorum (Orthoptera: Acrididae) in response to spider predation risk and elevated resource qualityECOLOGICAL ENTOMOLOGY, Issue 1 2004Bradford. Abstract., 1.,Predation risk to insects is often size- or stage-selective and usually decreases as prey grow. Any factor, such as food quality, that accelerates developmental and growth rates is likely to reduce the period over which prey are susceptible to size-dependent predation. 2.,Using field experiments, several hypotheses that assess growth, development, and egg production rates of the rangeland grasshopper Ageneotettix deorum (Scudder) were tested in response to combinations of food quality and predation risk from wolf spiders to investigate performance variation manifested through a behaviourally mediated path affecting food ingestion rates. 3.,Grasshoppers with nutritionally superior food completed development , 8,18% faster and grew 15,45% larger in the absence of spiders, in comparison with those subjected to low quality food exposed to spider predators. Growth and development did not differ for grasshoppers feeding on high quality food when predators were present in comparison with lower quality food unimpeded by predators. Responses indicated a compensatory relationship between resource quality and predation risk. 4.,Surviving grasshoppers produced fewer eggs compared with individuals not exposed to spiders. Because no differences were found in daily egg production rate regardless of predation treatment, lower egg production was attributed to delayed age of first reproduction. Results compare favourably with responses observed in natural populations. 5.,Risk of predation from spiders greatly reduced growth, development, and ultimately egg production. Increased food quality counteracts the impact of predation risk on grasshoppers through compensatory responses, suggesting that bottom-up factors mediate effects of spiders. [source] Growth and development in a high Arctic Collembola: adaptive variation in local populations living in contrasting thermal environmentsECOLOGICAL ENTOMOLOGY, Issue 1 2001Tone Birkemoe First page of article [source] Treatment of Idiopathic Hyperphosphatasia With Intensive Bisphosphonate TherapyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2004Tim Cundy MD Abstract In a family with IH, a rare high turnover bone disease, two older siblings were wheelchair-bound with severe skeletal deformity by age 15. Their youngest affected sibling was treated intensively with intravenous bisphosphonates for 3 years. The treatment was well tolerated and prevented the development of deformity and disability. Introduction: Idiopathic hyperphosphatasia (IH, also known as juvenile Paget's disease) is a rare genetic bone disease characterized by very high bone turnover and progressive bony deformity. Inhibitors of bone resorption have been used to suppress bone turnover in the short term, but there is no published data on long-term efficacy. Materials and Methods: An 11-year-old girl with IH, who had two severely affected older siblings, presented with progressive deformity and deafness and long bone fractures. Conventional pediatric doses of pamidronate had failed to prevent clinical deterioration or suppress bone turnover completely. Intensive bisphosphonate therapy (frequent 5-mg ibandronate infusions) was given to try and arrest progression of the skeletal disease. Growth and development, pure tone audiometry, biochemistry, radiology, densitometry (DXA), and bone histology were monitored. Results: A total of 45 mg ibandronate was given over 3 years until skeletal maturity was reached (20, 15, and 10 mg for years 1,3, respectively). Ibandronate treatment was well tolerated, and biochemical markers of bone turnover suppressed to within the age-appropriate normal range There was some progression of her thoracic kyphosis, but she had no further fractures and remained mobile and active at an age when her siblings had become wheelchair-bound. A significant recovery of hearing (p < 0.01) was documented, particularly at low frequencies. Radiographs showed improvement in spinal osteoporosis and cortical bone dimensions and arrest of progressive acetabular protrusion. Areal bone density increased substantially (lumbar spine z-score from ,2.2 to + 1.8). Tetracycline-labeled bone biopsy specimens were taken before and after 18 months of intensive treatment. The second biopsy showed suppression of bone turnover and a doubling of trabecular thickness, with no mineralization defect, and no osteopetrosis. Conclusions: Intensive bisphosphonate treatment prevented the development of deformity and disability and improved hearing in this child with IH. The dose of bisphosphonate, which is substantially greater than is usually used in pediatric bone disease, had no adverse effects, in particular on bone mineralization. [source] Growth and development of giant panda (Ailuropoda melanoleuca) cubs at Beijing ZooJOURNAL OF ZOOLOGY, Issue 2 2001Jianjun Peng Abstract We studied the postnatal body weight gain and development of 11 male and nine female giant panda Ailuropoda melanoleuca cubs born at Beijing Zoo from 1985 to 1998. Growth rates of the cubs appeared to be sexually dimorphic from the fourth month after birth; the male grew slightly faster than the female cubs. Growth rates between artificially fed and naturally fed cubs were significantly different from the fourth month after birth. The growth rate of the artificially fed cubs was slightly higher than that of the cubs fed by their mothers, indicating that the substitute milk satisfied the nutrient needs of the cubs. The body length of the cubs increased rapidly after birth; 8-month-old cubs were three times longer than newborn cubs. Chest circumferences of 8-month-old cubs also increased to twice that of newborn cubs. Tail length relative to body length was reduced from 14.9% at birth to about 8.6% in 8-month-old cubs. Cubs started to grow teeth when they were 3 months old. By the age of 1 year, the cubs had fully grown deciduous teeth. The teeth formula of one 1-year-old cub was 2·1·3·0/2·1·3·0=24. We recorded the changes in fur colour, development of the sense organs and limbs of the giant panda cubs. Finally, we compared the body weight and life-history parameters of giant pandas with those of bears and raccoons and discussed the management regime for the care of captive-born giant panda cubs. [source] CHARNIA AT 50: DEVELOPMENTAL MODELS FOR EDIACARAN FRONDSPALAEONTOLOGY, Issue 1 2008JONATHAN B. ANTCLIFFE Abstract:, Correct interpretation of the Ediacara biota is critical to our understanding of the dramatic events at the base of the Cambrian. We review here the history of thought and examine new laser images of the holotype of Charnia masoniFord, 1958, of the Ediacara biota, in terms of growth and development. Growth and development are argued to provide critical tools for understanding this and other enigmatic fossil groups. We show that Charnia cannot be related to the modern cnidarian group, the sea pens, with which it has for so long been compared, because they have opposite growth polarities. This is shown by our work on material collected by HMS challenger. Recent evolutionary studies also show that sea pens are a highly derived group of actively burrowing cnidarians that are likely to have evolved later than the Palaeozoic. The traditional paradigm of translating Phanerozoic animal phyla back into the Ediacaran is therefore questioned. [source] Growth and development: a special issueBIOESSAYS, Issue 1 2002Article first published online: 2 JAN 200 No abstract is available for this article. [source] The History of Dermatologic Surgical ReconstructionDERMATOLOGIC SURGERY, Issue 11 2000Daniel E. Zelac MD Over the last 40,50 years, reconstructive surgery in dermatology has undergone expansive growth and development. As dermatologists began to provide a greater array of surgical services during this period, it became apparent that new skills and techniques in the area of reconstruction would be required. Initially many of the procedures and concepts were adopted from other specialties, however, in the years since, significant contributions have been made by dermatologists which in turn have benefited other specialties as well. This review attempts to summarize some of the significant historical events and innovations that have established and supported dermatologic surgical reconstruction. [source] Effects of iodine supplementation during pregnancy on child growth and development at school ageDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 2 2002Karen J O'Donnell MEd PhD Growth and development of 207 children (49% males; mean age 5.4 years [SD 0.2], range 4 to 7.3 years whose mothers received iodine during pregnancy, and children who received iodine first in their 2nd year, were examined in 1996; 192 children(49% males; mean age 6.5 years[SD 0.2], range 5.8 to 6.9 years) whose mothers received iodine while pregnant were seen in 1998. Children were from the southern part of China's Xinjiang Province which has the lowest levels of iodine in water and soil ever recorded. Head circumference but not height was improved for those who received iodine during pregnancy (compared with those receiving iodine at age 2) and for those supplemented before the end of the 2nd trimester (relative to those supplemented during the 3rd trimester). Iodine before the 3rd trimester predicted higher psychomotor test scores for children relative to those provided iodine later in pregnancy or at 2 years. Results from the test for cognitive development resulted in trend only differences between those children supplemented during pregnancy versus later. The results address the question of when maternal iodine supplements should begin in public health programs world wide. Findings may be relevant to the treatment of maternal and newborn thyroid deficiency in industrialized countries, particularly for those infants delivered before the end of the second trimester. [source] MR imaging methods for assessing fetal brain developmentDEVELOPMENTAL NEUROBIOLOGY, Issue 6 2008Mary Rutherford Abstract Fetal magnetic resonance imaging provides an ideal tool for investigating growth and development of the brain in vivo. Current imaging methods have been hampered by fetal motion but recent advances in image acquisition can produce high signal to noise, high resolution 3-dimensional datasets suitable for objective quantification by state of the art post acquisition computer programs. Continuing development of imaging techniques will allow a unique insight into the developing brain, more specifically process of cell migration, axonal pathway formation, and cortical maturation. Accurate quantification of these developmental processes in the normal fetus will allow us to identify subtle deviations from normal during the second and third trimester of pregnancy either in the compromised fetus or in infants born prematurely. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008 [source] Selection for discontinuous life-history traits along a continuous thermal gradient in the butterfly Aricia agestisECOLOGICAL ENTOMOLOGY, Issue 6 2005Steve Burke Abstract., 1.,Voltinism may be conceptualised as the product of development rate and the timing of diapause , two components that together translate gradual environmental variation, through periods of growth and development, into ,generational units'. This may result in very different selection pressures on diapause induction and development time in populations with different numbers of generations per year. 2.,Developmental data from univoltine and bivoltine populations of the butterfly Aricia agestis (Lepidoptera: Lycaenidae) in North Wales were used to examine larval development time and the timing of diapause, and their contribution towards voltinism in populations that occur at the same latitude and in geographic proximity to one another along a thermal gradient. 3.,The critical photoperiod for diapause induction in univoltines and bivoltines from the same latitude differed by more than 1.5 h. 4.,Development time also differed significantly between these populations, in line with predictions that bivoltines would need to exhibit shorter development times in order to achieve two complete generations per year. Shorter development times for bivoltines result in lower pupal weights, suggesting a trade-off exists between generation number and body size that may dictate the position of the transition zone between the two life-history strategies. Analysis of development times in a third population, from southern England, with greater thermal availability than those from North Wales, further supports this hypothesised trade-off. 5.,To achieve the conversion of a continuous thermal gradient into the binary biological response from univoltism to bivoltism, bivoltines speed up development, reduce adult body size and shift their diapause induction response. [source] MANAGING EDUCATIONAL TRANSFORMATION IN THE GLOBALIZED WORLD: A DEWEYAN PERSPECTIVEEDUCATIONAL THEORY, Issue 4 2009Maura Striano In the globalization scenarios we currently face, educational systems are challenged by different and sometimes competing pressures and requests. These call for a deep transformation of the organization, role, and social function of educational systems. Within this context, the very concept of education has come to be understood in different ways, which sometimes distort its moral and social value. In this essay, Maura Striano contends that from a Deweyan perspective, educational transformation must be seen as strictly connected to social change, and education should be understood as a process that facilitates and supports social growth and development. In order to be effective and fruitful, Striano suggests, this transformation must occur from the inside of educational systems and can only be brought about by reflective and inquiry-based inner processes if it is to have a sound moral and social impact within the changing framework of the globalized world. That education shares in the confusion of transition, and in the demand for reorganization, is a source of encouragement and not of despair. It proves how integrally the school is bound up with the entire movement of modern life. ,John Dewey, The Educational Situation [source] Impact of a parasitoid on the bacterial symbiosis of its aphid hostENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2003Conrad Cloutier Abstract Embryo production in aphids is absolutely dependent on the function of symbiotic bacteria, mainly Buchnera, and the growth and development of koinobiont parasitoids in aphids requires the diversion of nutrients from aphid embryo production to the parasitoid. The implication that the bacterial symbiosis may be promoted in parasitized aphids to support the growing parasitoid was explored by analysis of the number and biomass of mycetocytes, and the aphid cells bearing Buchnera, in the pea aphid Acyrthosiphon pisum Harris (Hemiptera: Aphididae) parasitized by the wasp Aphidius ervi Haliday (Hymenoptera: Braconidae). Aphids hosting a young larval parasitoid bore more mycetocytes of greater total biomass, and embryos of lower biomass than unparasitized aphids. Furthermore, one of the three aphid clones tested, which limited teratocyte growth (giant cells of parasitoid origin having a trophic role), bore smaller mycetocytes and larger embryos, than one or both of the two aphid clones with greater susceptibility to the parasitoid. These data suggest that susceptibility of the aphid- Buchnera symbiosis to parasitoid-mediated manipulation may, directly or indirectly, contribute to aphid susceptibility to parasitoid exploitation. [source] Critical period of sensitivity for effects of cadmium on frog growth and development,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2009Jackson A. Gross Abstract Cadmium is a ubiquitous pollutant in aquatic environments that can alter organismal physiology and ecology. Previous experiments found that ecological Cd exposures increased the growth and development of two North American anurans. However, the generality of these effects among species, the time period over which they occur, and the mechanisms responsible remain conjectural. The goal of the present study was to determine the critical period of sensitivity of Rana pipiens exposed to ecologically relevant levels of Cd. We exposed tadpoles to Cd (0 [control], 1.0, and 10.0 ,g/L) from Gosner stage (GS) 25 to metamorphic climax. We assessed effects of Cd on amphibian length, survival, and development during premetamorphosis (GS 25,30) and prometamorphosis (GS 31,42). After 14 d of exposure, we staged tadpoles and recorded snout-vent length. Tadpoles were then pooled according to treatment and stage (GS , 29 or GS , 30) and allowed to undergo metamorphic development. Tadpoles exposed to 10 ,g/L were significantly larger and more advanced in development by 14 d. Survival to forelimb emergence exceeded 90% in all treatments, and time to metamorphic climax was not different from that in controls. Body burdens of Cd were positively correlated with increasing treatment. Early amphibian development (premetamorphosis) was shown to be the critical period of sensitivity for growth and development. Whereas the freshwater criterion for Cd appears to be protective for survival, a lack of knowledge remains about the sublethal effects of chronic exposures of metal pollutants, especially as they relate to tissue concentrations at various stages of amphibian life history. [source] Effects of the synthetic estrogen ethinylestradiol on early life stages of mink frogs and green frogs in the wild and in situENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2005Bradley J. Park Abstract Estrogenic contaminants are known to disrupt growth and development in amphibians. Field-based research is needed to elucidate their potential impacts on wild populations. Hatch success, larval growth and development rates, and gonad development were examined in native amphibians exposed to low ng/L concentrations of 17,-efhinylestradiol (EE2) in a whole-lake addition experiment at the Experimental Lakes Area, northwestern Ontario, Canada. Egg masses were reared in situ in the EE2-amended lake and in two reference lakes in 2001 and 2002. Hatching success was reduced significantly in green frogs (Rana clamitans) but not in mink frogs (Rana septentrionalis) exposed to EE2. Ethinylestradiol had no consistent effect on mass or development stage of hatchlings in the early larval stages of the caging study. Ethinylestradiol had no effect on sex ratios of either species in situ, and no intersex gonads were observed in exposed or reference green frog tadpoles or in reference mink frog tadpoles. However, 5.6% (total n = 18) and 12.5% (total n = 56) of EE2-exposed mink frog tadpoles were intersex in the 2001 and 2002 caging studies, respectively. Wild mink frog tadpoles also were examined, and EE2 had no effect on sex ratios. No intersex gonads were observed in reference lake tadpoles or in tadpoles from the experimental lake prior to EE2 additions; however, 2.4, 0, and 28.6% of wild EE2-exposed first-year tadpoles had intersex gonads (2001, 2002, and 2003, respectively). These results indicate that exposure to EE2 in the wild and in situ at concentrations comparable to those detected in effluents and, occasionally, in surface waters can impact gonad development and hatch success in native amphibians. [source] Exposure to the polychlorinated biphenyl mixture Aroclor® 1254 alters melanocyte and tail muscle morphology in developing Xenopus laevis tadpolesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2003Marla A. Fisher Abstract Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that have damaging effects on both ecosystem and human health. Numerous studies have shown that exposure to PCBs can alter growth and development of aquatic organisms, including frogs. In this report, developing Xenopus laevis tadpoles were exposed to the PCB mixture Aroclor® 1254. Tadpoles were exposed from 5 through 9 d postfertilization to either 0, 1, 10, 50, or 100 ppm Aroclor 1254. Exposure to an acute, high concentration of Aroclor 1254 (10, 50, and 100 ppm) caused statistically significant reductions in survival and body size. In addition, tadpoles exposed to these higher concentrations showed histological abnormalities, including aberrant tail tip, myotomal, and melanocyte morphologies. Described adverse health effects associated with PCB exposure of developing frogs will serve as useful health endpoints in ongoing and future molecular-based studies that correlate health effects with changes in gene expression. [source] Vocational Education and Training and Human Capital Development: current practice and future optionsEUROPEAN JOURNAL OF EDUCATION, Issue 2 2010MANFRED WALLENBORN EU neighbouring countries (partner countries) have made considerable efforts to improve their vocational education and training (VET) systems, with different policies and strategies that take account of country-specific priorities in human capital development. This article addresses the donor community. It analyses the role of partner countries' VET in contributing to human capital development in order to benefit better from the globalised economy. The emerging debate on the role of VET in these countries and among donors is considered in terms of the functional dimensions of employability, productivity and sustainable growth, taking into account the economic, social and ecological dimension of growth and development. Not addressed is the systemic perspective on VET in terms of improving existing curricula, learning arrangements and textbooks. The article focuses, rather, on functional dimensions of VET that are relevant to achieve development goals and makes some recommendations for international cooperation. Given the complexity of multi-stakeholder-driven VET systems, cooperation needs to build on existing VET structures. Moreover, cooperation must contribute to an effective reform implementation. [source] Too much of a good thing: retinoic acid as an endogenous regulator of neural differentiation and exogenous teratogenEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003P. J. McCaffery Abstract Retinoic acid (RA) is essential for both embryonic and adult growth, activating gene transcription via specific nuclear receptors. It is generated, via a retinaldehyde intermediate, from retinol (vitamin A). RA levels require precise regulation by controlled synthesis and catabolism, and when RA concentrations deviate from normal, in either direction, abnormal growth and development occurs. This review describes: (i) how the pattern of RA metabolic enzymes controls the actions of RA; and (ii) the type of abnormalities that result when this pattern breaks down. Examples are given of RA control of the anterior/posterior axis of the hindbrain, the dorsal/ventral axis of the spinal cord, as well as certain sex-specific segments of the spinal cord, using varied animal models including mouse, quail and mosquitofish. These functions are highly sensitive to abnormal changes in RA concentration. In rodents, the control of neural patterning and differentiation are disrupted when RA concentrations are lowered, whereas inappropriately high concentrations of RA result in abnormal development of cerebellum and hindbrain nuclei. The latter parallels the malformations seen in the human embryo exposed to RA due to treatment of the mother with the acne drug Accutane (13- cis RA) and, in cases where the child survives beyond birth, a particular set of behavioural anomalies can be described. Even the adult brain may be susceptible to an imbalance of RA, particularly the hippocampus. This report shows how the properties of RA as a neural induction agent and organizer of segmentation can explain the consequences of RA depletion and overexpression. [source] ORIGINAL ARTICLE: Big dams and salmon evolution: changes in thermal regimes and their potential evolutionary consequencesEVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 2 2008Michael J. Angilletta Jr Abstract Dams designed for hydropower and other purposes alter the environments of many economically important fishes, including Chinook salmon (Oncorhynchus tshawytscha). We estimated that dams on the Rogue River, the Willamette River, the Cowlitz River, and Fall Creek decreased water temperatures during summer and increased water temperatures during fall and winter. These thermal changes undoubtedly impact the behavior, physiology, and life histories of Chinook salmon. For example, relatively high temperatures during the fall and winter should speed growth and development, leading to early emergence of fry. Evolutionary theory provides tools to predict selective pressures and genetic responses caused by this environmental warming. Here, we illustrate this point by conducting a sensitivity analysis of the fitness consequences of thermal changes caused by dams, mediated by the thermal sensitivity of embryonic development. Based on our model, we predict Chinook salmon likely suffered a decrease in mean fitness after the construction of a dam in the Rogue River. Nevertheless, these demographic impacts might have resulted in strong selection for compensatory strategies, such as delayed spawning by adults or slowed development by embryos. Because the thermal effects of dams vary throughout the year, we predict dams impacted late spawners more than early spawners. Similar analyses could shed light on the evolutionary consequences of other environmental perturbations and their interactions. [source] Bumetanide, the Specific Inhibitor of Na+ -K+ -2Cl, Cotransport, Inhibits 1,,25-Dihydroxyvitamin D3 -Induced Osteoclastogenesis in a Mouse co-culture SystemEXPERIMENTAL PHYSIOLOGY, Issue 5 2003Hyun-A Lee The Na+ -K+ -2Cl, cotransporter (NKCC1) is responsible for ion transport across the secretory and absorptive epithelia, the regulation of cell volume, and possibly the modulation of cell growth and development. It has been reported that a variety of cells, including osteoblasts, contain this cotransporter. In this study, the physiological role of NKCC1 in osteoclastogenesis was exploited in a co-culture system. Bumetanide, a specific inhibitor of NKCC1, reduced the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. In order to investigate the mechanism by which bumetanide inhibits osteoclastogenesis, the mRNA expressions of the receptor activator of nuclear factor (NF)-,B ligand (RANKL) and osteoprotegerin (OPG) were analysed by RT-PCR. Exposure of osteoblastic cells to a medium containing 1 µM bumetanide reduced RANKL mRNA expression induced by 10 nM 1,,25-dihydroxyvitamin D3 (1,,25(OH)2D3, in a dose-dependent manner. In addition, RANKL expression was also analysed with enzyme-linked immunosorbant assay (ELISA) using anti-RANKL antibody. The expression of RANKL was decreased with the increase of bumetanide concentration. In contrast, the expression of OPG mRNA, a novel tumour necrosis factor (TNF) receptor family member was increased in the presence of bumetanide. These results imply that bumetanide inhibits osteoclast differentiation by reducing the RANKL/OPG ratio in osteoblastic cells. However, no significant difference in M-CSF mRNA expression was observed when bumetanide was added. Also, we found that the phosphorylation of c-Jun NH2 -terminal kinase (JNK), which regulates the activity of various transcriptional factors, was reduced by bumetanide treatment. Conclusively, these findings suggest that NKCC1 in osteoblasts has a pivotal role in 1,,25(OH)2D3 -induced osteoclastogenesis partly via the phosphorylation of JNK. [source] Combined Confocal Microscopy and Stereology: a Highly Efficient and Unbiased Approach to Quantitative Structural Measurement in TissuesEXPERIMENTAL PHYSIOLOGY, Issue 6 2002Katherine Howell Understanding the relationship of the structure of organs to their function is a key component of integrative physiological research. The structure of the organs of the body is not constant but changes, both during growth and development and under conditions of sustained stress (e.g. high altitude exposure and disease). Recently, powerful new techniques have become available in molecular biology, which promise to provide novel insights into the mechanisms and consequences of these altered structure-function relationships. Conventionally structure-function relationships are studied by microscopic examination of tissue sections. However, drawing conclusions about the three-dimensional structure of an organ based on this two-dimensional information frequently leads to serious errors. The techniques of stereology allow precise and accurate quantification of structural features within three-dimensional organs that relate in a meaningful way to integrated function. For example, knowledge of changes in the total surface area of the capillary endothelium in an organ can be related directly to changes in fluid filtration and permeability, or knowledge of total vessel length and mean radius allows deductions about vascular resistance. Confocal microscopy adds enormously to the power of stereological approaches. It reduces the difficulties and labour involved in obtaining suitable images. Moreover, when used in conjunction with new analytical software, it allows convenient application of stereology to small samples and those in which it is essential to maintain a specific orientation for interpretation. The information obtained will allow us to examine in a quantitative manner the altered structure-function relationships produced by manipulation of single genes and regulatory pathways in whole organisms. [source] An ecdysteroid-inducible insulin-like growth factor-like peptide regulates adult development of the silkmoth Bombyx moriFEBS JOURNAL, Issue 5 2009Naoki Okamoto Insulin-like growth factors (IGFs) play essential roles in fetal and postnatal growth and development of mammals. They are secreted by a wide variety of tissues, with the liver being the major source of circulating IGFs, and regulate cell growth, differentiation and survival. IGFs share some biological activities with insulin but are secreted in distinct physiological and developmental contexts, having specific functions. Although recent analyses of invertebrate genomes have revealed the presence of multiple insulin family peptide genes in each genome, little is known about functional diversification of the gene products. Here we show that a novel insulin family peptide of the silkmoth Bombyx mori, which was purified and sequenced from the hemolymph, is more like IGFs than like insulin, in contrast to bombyxins, which are previously identified insulin-like peptides in B. mori. Expression analysis reveals that this IGF-like peptide is predominantly produced by the fat body, a functional equivalent of the vertebrate liver and adipocytes, and is massively released during pupa,adult development. Studies using in vitro tissue culture systems show that secretion of the peptide is stimulated by ecdysteroid and that the secreted peptide promotes the growth of adult-specific tissues. These observations suggest that this peptide is a Bombyx counterpart of vertebrate IGFs and that functionally IGF-like peptides may be more ubiquitous in the animal kingdom than previously thought. Our results also suggest that the known effects of ecdysteroid on insect adult development may be in part mediated by IGF-like peptides. [source] Genome-wide identification, classification, evolutionary expansion and expression analyses of homeobox genes in riceFEBS JOURNAL, Issue 11 2008Mukesh Jain Homeobox genes play a critical role in regulating various aspects of plant growth and development. In the present study, we identified a total of 107 homeobox genes in the rice genome and grouped them into ten distinct subfamilies based upon their domain composition and phylogenetic analysis. A significantly large number of homeobox genes are located in the duplicated segments of the rice genome, which suggests that the expansion of homeobox gene family, in large part, might have occurred due to segmental duplications in rice. Furthermore, microarray analysis was performed to elucidate the expression profiles of these genes in different tissues and during various stages of vegetative and reproductive development. Several genes with predominant expression during various stages of panicle and seed development were identified. At least 37 homeobox genes were found to be differentially expressed significantly (more than two-fold; P < 0.05) under various abiotic stress conditions. The results of the study suggest a critical role of homeobox genes in reproductive development and abiotic stress signaling in rice, and will facilitate the selection of candidate genes of agronomic importance for functional validation. [source] Influence of arbuscular mycorrhizal mycelial exudates on soil bacterial growth and community structureFEMS MICROBIOLOGY ECOLOGY, Issue 2 2007Jonas F. Toljander Abstract Plant root systems colonized by arbuscular mycorrhizal (AM) fungi have previously been shown to influence soil bacterial populations; however, the direct influence of the AM extraradical mycelium itself on bacterial growth and community composition is not well understood. In this study, we investigated the effects of exudates produced by AM extraradical mycelia on the growth and development of an extracted soil bacterial community in vitro. The chemical composition of the mycelial exudates was analysed using proton nuclear magnetic resonance spectrometry. Following the addition of exudates to a bacterial community extracted from soil, bacterial growth and vitality were determined using a bacterial vitality stain and fluorescence microscopy. Changes in community composition were also analysed at various times over the course of 3 days by terminal restriction fragment length polymorphism analysis, in combination with cloning and sequencing of 16S rRNA genes. Mycelial exudates increased bacterial growth and vitality and changed bacterial community composition. Several Gammaproteobacteria, including a taxon within the Enterobacteriaceae, increased in frequency of occurrence in response to AM mycelial exudates. This study is the first attempt to identify carbohydrates from the extraradical mycelium of an AM fungus, and demonstrates the direct effects of mycelial exudates on a soil bacterial community. [source] Plasmodium falciparum growth is arrested by monoterpenes from eucalyptus oilFLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2008Vanessa Su Abstract Cerebral malaria is a major health problem in the developing world. Widespread resistance to existing drugs by the parasite Plasmodium falciparum has coincided with an increase in mortality, particularly in children. One potential source of new drugs comes from plant natural products. We found that commercially available, pharmaceutical grade eucalyptus oil and its principal component 1,8-cineole inhibited the growth and development of chloroquine-sensitive and chloroquine-resistant P. falciparum. This was true both when the oil was added directly to the parasite cultures and when cultures were exposed to the vapours. The development of the parasite was arrested at the early trophozoite stage, irrespective of when the oil was introduced. We used a new approach where the concentration of monoterpenes actually taken up by the cultures was measured directly using HS,GC. We found that the critical concentration required to inhibit and kill the parasite did not adversely affect the host erythrocytes, placing it in the range suitable for drug development. Given the ready availability and existing quality control of eucalyptus oils, this may represent an economically viable adjunct to current antimalarial therapies. Copyright © 2008 John Wiley & Sons, Ltd. [source] Carry-over effects of embryonic acid conditions on development and growth of Rana temporaria tadpolesFRESHWATER BIOLOGY, Issue 1 2002K. RÄsänen 1.,Conditions experienced during the early stages of development may have carry-over effects on performance during later life. The egg laying period and embryonic development of temperate and boreal zone amphibians often coincides with peak acidity resulting from spring snow-melt, but the effects of acid conditions during embryonic stage on subsequent performance are unknown. 2.,We investigated the potential carry-over effects of acidity during the embryonic stage on performance up to metamorphosis in the common frog (Rana temporaria) tadpoles. There were four combinations of acid (4.5) and neutral (7.5) pH treatments applied to the egg and larval stages in a factorial laboratory experiment. In addition, we studied the difference in embryonic and larval tolerance of acidity between two populations originating from circumneutral (pH 6.6) and acidic conditions (pH 4.8). 3.,The effects of acid conditions during the embryonic stage were sublethal, as indicated by delayed development and reduced size. Under acid conditions, tadpoles that had been raised in neutral water as embryos at first grew more slowly than tadpoles raised under acid conditions as embryos. At metamorphosis, no effects of embryonic acidity were detectable indicating that tadpoles were able to compensate fully for the initial reduction in growth. 4.,Acid conditions during the larval period had a strongly negative effect on survival, size and age at metamorphosis. The amount of food consumed was lower under acid conditions, suggesting that reduced food consumption was at least partly responsible for the negative effects. 5.,Although the two populations differed in the length of larval period, there was no indication of a differential response to the treatments in any of the metamorphic traits studied. 6.,These results suggest that, although moderate acid conditions during embryonic development affect growth and development negatively, this influence does not persist after conditions have returned to normal. However, even moderately acid conditions during the larval period may have a strong negative influence on survival and performance of the tadpoles. [source] | ||||||||||||||||||||||||||||||||||||||||||||||