Home About us Contact
|
Home About us Contact | ||
|
|
||
Growth Velocity (growth + velocity)
Selected AbstractsGrowth velocity standards from longitudinally measured infants of age 0,2 years born in Shiraz, southern IranAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2005S.M.T. Ayatollahi This paper presents growth velocity data for a cohort of 317 infants (164 girls and 153 boys) born in Shiraz, southern Iran, in 1996 and followed longitudinally for 2 years. The growth velocity of five anthropometric measurements (height, weight, arm, head, and chest circumferences) declined rapidly from 2 weeks to 7 months of age and less steeply thereafter for both sexes. Growth velocities for boys were higher than girls in the first months but did not differ significantly later on. However, growth velocity centiles for girls lie below those for boys throughout the age range studied. Weight velocities in the Iranian infants were significantly lower than for corresponding infants in the U.K., the Middle East, and Africa, but height velocities were generally higher. Am. J. Hum. Biol. 17:302,309, 2005. © 2005 Wiley-Liss, Inc. [source] GH responsiveness in a large multinational cohort of SGA children with short stature (NESTEGG) is related to the exon 3 GHR polymorphismCLINICAL ENDOCRINOLOGY, Issue 3 2007M. Tauber Summary Objective, The polymorphic deletion of exon 3 of the GH receptor (d3-GHR) has recently been linked to the magnitude of growth response to recombinant human GH (rhGH) therapy in short children with or without GH deficiency. We investigated this association in a large multinational cohort from the Network of European Studies of Genes in Growth (NESTEGG), comprising short children born small for gestational age (SGA). Design, The study included short prepubertal SGA children treated with rhGH for 1 or 2 years. Population, Two hundred and forty white Caucasian SGA children (138 male, 102 female) aged 6·6 ± 2·3 years with a height at ,3·0 ± 0·7 SDS at start of rhGH treatment; 193 ethnically matched controls. Methods, The GHR polymorphism (fl/fl, fl/d3 or d3/d3) was genotyped by polymerase chain reaction (PCR) multiplex assay. Growth velocity (G/V) in cm/year and changes in GV during the first and second year of rhGH treatment were evaluated. Results, The change in GV was significantly greater in SGA children carrying one or two copies of the d3-GHR allele (P = 0·038 for the first year and P = 0·041 for the second year of GH treatment), but the change in height was not significantly different. Birthweight was significantly lower in SGA children with the d3/d3 genotype than in SGA children with the fl/fl genotype (P = 0·034) and in those with the fl/d3 genotype (P = 0·016). Conclusion, Our data, based on a large cohort, showed that the exon 3 GHR polymorphism is associated with responsiveness to rhGH treatment in SGA children with short stature. [source] Morphological study of Czochralski-grown lanthanide orthovanadate single crystals and implications on the mechanism of bulk spiral formationJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2010Hengjiang Cong Single crystals of monoclinic Nd:LaVO4 with dimensions up to Ø28 × 21,mm have been grown from the near-stoichiometric melt by the Czochralski method, making use of various seed orientations that are perpendicular to the (010), (10), (001) and (00) crystal planes. A sample was also prepared with the seed orientation in an arbitrary direction relative to the crystal. The anisotropic properties of the crystal are manifested in the growth morphology of the as-grown crystals, where different degrees of bulk spiral growth were observed. It was also found that employing the (001) or (00) seed faces severely suppressed the bulk spiral growth, and thus high quality and large-scale Nd:LaVO4 crystals were obtained. The constituent segregation coefficients and high-temperature stability, including the melting point, were determined and evaluated. Based on the attachment energy model of Hartman,Perdok theory, morphology predictions were made for monoclinic LaVO4 and tetragonal YVO4 orthovanadate single crystals. Correlating with the as-grown morphology of both crystals developed along different seed orientations, a theoretical explanation is provided for the influences of seed crystals on bulk spiral formation, crystal quality and utilization ratio. It suggests that breaking the axial symmetry of the ideal atomic level interface between crystal and melt plays a crucial triggering role in bulk spiral formation in the Czochralski growth of lanthanide orthovanadate single crystals. Selecting a proper seed orientation that yields such a highly axially symmetric surface structure consisting of a series of large-area facets with similar growth velocities can greatly reduce bulk spiral formation and thus is preferable in the Czochralski growth of large-sized low-symmetry oxide crystals. [source] Bone and Muscle Development During Puberty in Girls: A Seven-Year Longitudinal Study,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2009Leiting Xu Abstract The growth of lean mass precedes that of bone mass, suggesting that muscle plays an important role in the growth of bone. However, to date, no study has directly followed the growth of bone and muscle size through puberty and into adulthood. This study aimed to test the hypothesis that the growth of muscle size precedes that of bone size (width and length) and mass during puberty. Bone and muscle properties were measured using pQCT and DXA in 258 healthy girls at baseline (mean age, 11.2 yr) and 1-, 2-, 3,4- and 7-yr follow-up. Growth trends as a function of time relative to menarche were determined from prepuberty to early adulthood for tibial length (TL), total cross-sectional area (tCSA), cortical CSA (cCSA), total BMC (tBMC), cortical volumetric BMD (cBMD), and muscle CSA (mCSA) in hierarchical models. The timings of the peak growth velocities for these variables were calculated. Seventy premenopausal adults, comprising a subset of the girl's mothers (mean age, 41.5 yr), were included for comparative purposes. In contrast to our hypothesis, the growth velocity of mCSA peaked 1 yr later than that of tibial outer dimensions (TL and tCSA) and slightly earlier than tBMC. Whereas TL ceased to increase 2 yr after menarche, tCSA, cCSA, tBMC, and mCSA continued to increase and were still significantly lower than adult values at the age of 18 yr (all p < 0.01). The results do not support the view that muscle force drives the growth of bone size during puberty. [source] New reference for the age at childhood onset of growth and secular trend in the timing of puberty in SwedishACTA PAEDIATRICA, Issue 6 2000YX Liu The objectives of the present work were to present a new reference for the age at childhood onset of growth and to investigate the secular trend in the timing of puberty in a community-based normal population in Sweden. A total of 2432 children with longitudinal length/height data from birth to adulthood were used to determine the two measures by visual inspection of the measured attained length/height and the change in growth velocity displayed on a computer-generated infancy-childhood-puberty (ICP) based growth chart. The series represents a sample of normal full-term children born around 1974 in Göteborg, Sweden. We found about 10% of children were delayed (>12 mo of age) in the childhood onset of growth based on the previous reported normal range, i.e. 14% in boys and 8% in girls. Distribution of the age at childhood onset of growth was skewed. The medians were 10 and 9 mo for boys and girls, respectively. After natural logarithmic transformation, the mean and standard deviation (SD) were 2.29 (anti-log 9.9 mo) and 0.226 for boys, 2.23 (anti-log 9.3 mo) and 0.220 for girls, respectively. The 95% normal ranges were 6.3-15.4 and 6.0-14.3 for boys and girls, respectively. The distribution of the timing of PHV was close to the normal distribution. The mean values were 13.5 y for boys and 11.6 y for girls with 1 y SD for both sexes. Conclusion: A downward secular trend in the onset of puberty was clearly shown in the population. The age at childhood onset of growth did not correlate with the timing of puberty (r=,0.01 and 0.05, p > 0.7 and 0.1 in boys and girls, respectively). Normal ranges of the age at childhood onset of growth are in need of revise, as this study indicates. The new reference presented here could be a reliable indicator in further studies. [source] Temperature field design, process analysis and control of SAPMAC method for the growth of large size sapphire crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2007C. H. Xu Abstract In this paper, the relationship between quality of sapphire crystal and growing parameters of SAPMAC (Sapphire growth technique with micro-pulling and shoulder-expanding at cooled center) method was discussed. Optimized temperature distribution and technique control were proposed by theoretical analysis, numerical simulation computation and experimental validation to obtain large size sapphire crystals. For a-axis crystallized direction, with 1.0-5.0mm/h growth velocity and 10-30K/h temperature decreasing speed, large sapphire single crystal (,240mm×210mm, 27.5kg) having high optical quality was successfully grown. The absorption spectrum of standard samples was measured as well. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Silicon Nanowires: A Review on Aspects of their Growth and their Electrical PropertiesADVANCED MATERIALS, Issue 25-26 2009Volker Schmidt Abstract This paper summarizes some of the essential aspects of silicon-nanowire growth and of their electrical properties. In the first part, a brief description of the different growth techniques is given, though the general focus of this work is on chemical vapor deposition of silicon nanowires. The advantages and disadvantages of the different catalyst materials for silicon-wire growth are discussed at length. Thereafter, in the second part, three thermodynamic aspects of silicon-wire growth via the vapor,liquid,solid mechanism are presented and discussed. These are the expansion of the base of epitaxially grown Si wires, a stability criterion regarding the surface tension of the catalyst droplet, and the consequences of the Gibbs,Thomson effect for the silicon wire growth velocity. The third part is dedicated to the electrical properties of silicon nanowires. First, different silicon nanowire doping techniques are discussed. Attention is then focused on the diameter dependence of dopant ionization and the influence of interface trap states on the charge carrier density in silicon nanowires. It is concluded by a section on charge carrier mobility and mobility measurements. [source] Inverse design of directional solidification processes in the presence of a strong external magnetic fieldINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2001Rajiv Sampath Abstract A computational method for the design of directional alloy solidification processes is addressed such that a desired growth velocity ,f under stable growth conditions is achieved. An externally imposed magnetic field is introduced to facilitate the design process and to reduce macrosegregation by the damping of melt flow. The design problem is posed as a functional optimization problem. The unknowns of the design problem are the thermal boundary conditions. The cost functional is taken as the square of the L2 norm of an expression representing the deviation of the freezing interface thermal conditions from the conditions corresponding to local thermodynamic equilibrium. The adjoint method for the inverse design of continuum processes is adopted in this work. A continuum adjoint system is derived to calculate the adjoint temperature, concentration, velocity and electric potential fields such that the gradient of the L2 cost functional can be expressed analytically. The cost functional minimization process is realized by the conjugate gradient method via the FE solutions of the continuum direct, sensitivity and adjoint problems. The developed formulation is demonstrated with an example of designing the boundary thermal fluxes for the directional growth of a germanium melt with dopant impurities in the presence of an externally applied magnetic field. The design is shown to achieve a stable interface growth at a prescribed desired growth rate. Copyright © 2001 John Wiley & Sons, Ltd. [source] The shifting trajectory of growth in femur length during gestationJOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2010Åshild Bjørnerem Abstract Bone size is a determinant of bone strength and tracks in its percentile of origin during childhood and adolescence. We hypothesized that the ranking of an individual's femur length (FL) is established in early gestation and tracks thereafter. Fetal FL was measured serially using 2D ultrasound in 625 Norwegian fetuses. Tracking was assessed using Pearson correlation, a generalized estimating equation model, and by calculating the proportion of fetuses whose FL remained within the same quartile. Baseline FL Z -score (weeks 10 to 19) and later measurements correlated, but more weakly as gestation advanced: r,=,0.59 (weeks 20 to 26); r,=,0.45 (weeks 27 to 33); and r,=,0.32 (weeks 34 to 39) (p,<,0.001). Tracking within the same quartile throughout gestation occurred in 13% of fetuses. Of the 87% deviating, 21% returned to the quartile of origin, so 34% began and ended in the same quartile, 38% deviated by one quartile, and 28% deviated by two or more quartiles by the end of gestation. A standard deviation higher baseline FL Z -score, placental weight (150,g), maternal height (5,cm), and weight (10,kg), was associated with a 0.25, 0.15, 0.10, and 0.05 SD higher FL Z -score at the end of gestation, respectively (p ranging from <0.001 to 0.02). Tracking within the same percentile throughout the whole of gestation, as suggest by growth charts, is uncommon. Deviation from tracking is more common and is the result of changes in growth velocity within and between fetuses and is partly influenced by maternal, fetal, and placental factors. © 2010 American Society for Bone and Mineral Research [source] Bone and Muscle Development During Puberty in Girls: A Seven-Year Longitudinal Study,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2009Leiting Xu Abstract The growth of lean mass precedes that of bone mass, suggesting that muscle plays an important role in the growth of bone. However, to date, no study has directly followed the growth of bone and muscle size through puberty and into adulthood. This study aimed to test the hypothesis that the growth of muscle size precedes that of bone size (width and length) and mass during puberty. Bone and muscle properties were measured using pQCT and DXA in 258 healthy girls at baseline (mean age, 11.2 yr) and 1-, 2-, 3,4- and 7-yr follow-up. Growth trends as a function of time relative to menarche were determined from prepuberty to early adulthood for tibial length (TL), total cross-sectional area (tCSA), cortical CSA (cCSA), total BMC (tBMC), cortical volumetric BMD (cBMD), and muscle CSA (mCSA) in hierarchical models. The timings of the peak growth velocities for these variables were calculated. Seventy premenopausal adults, comprising a subset of the girl's mothers (mean age, 41.5 yr), were included for comparative purposes. In contrast to our hypothesis, the growth velocity of mCSA peaked 1 yr later than that of tibial outer dimensions (TL and tCSA) and slightly earlier than tBMC. Whereas TL ceased to increase 2 yr after menarche, tCSA, cCSA, tBMC, and mCSA continued to increase and were still significantly lower than adult values at the age of 18 yr (all p < 0.01). The results do not support the view that muscle force drives the growth of bone size during puberty. [source] Positive Linear Growth and Bone Responses to Growth Hormone Treatment in Children With Types III and IV Osteogenesis Imperfecta: High Predictive Value of the Carboxyterminal Propeptide of Type I Procollagen,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2003Joan C Marini MD Abstract Extreme short stature is a cardinal feature of severe osteogenesis imperfecta (OI), types III and IV. We conducted a treatment trial of growth hormone in children with OI and followed linear growth velocity, bone metabolism markers, histomorphometrics, and vertebral bone density. Twenty-six children with types III and IV OI, ages 4.5,12 years, were treated with recombinant growth hormone (rGH), 0.1,0.2 IU/kg per day for 6 days/week, for at least 1 year. Length, insulin-like growth factor (IGF-I), insulin-like growth factor binding protein (IGFBP-3), bone metabolic markers, and vertebral bone density by DXA were evaluated at 6-month intervals. An iliac crest biopsy was obtained at baseline and 12 months. Approximately one-half of the treated OI children sustained a 50% or more increase in linear growth over their baseline growth rate. Most responders (10 of 14) had moderate type IV OI. All participants had positive IGF-I, IGFBP-3, osteocalcin, and bone-specific alkaline phosphatase responses. Only the linear growth responders had a significant increase in vertebral DXA z-score and a significant decrease in long bone fractures. After 1 year of treatment, responders' iliac crest biopsy showed significant increases in cancellous bone volume, trabecular number, and bone formation rate. Responders were distinguished from nonresponders by higher baseline carboxyterminal propeptide (PICP) values (p < 0.05), suggesting they have an intrinsically higher capacity for collagen production. The results show that growth hormone can cause a sustained increase in the linear growth rate of children with OI, despite the abnormal collagen in their bone matrix. In the first year of treatment, growth responders achieve increased bone formation rate and density, and decreased fracture rates. The baseline plasma concentration of PICP was an excellent predictor of positive response. [source] Growth patterns in children with sickle cell anemia during pubertyPEDIATRIC BLOOD & CANCER, Issue 4 2009Melissa Rhodes MD Abstract Background Previous studies of children with homozygous sickle cell anemia (SCA) show impaired growth and maturation. The correlation of this suboptimal growth with metabolic and hematological factors during puberty is poorly understood. Procedure We studied a group of pre-adolescent children with SCA (19 males, 14 females) and healthy controls (16 males, 15 females) matched for race, sex, body size, and pubertal development. Height, weight, body mass index (BMI), and body composition changes were longitudinally assessed over a 2-year period and compared between the groups and with Z scores based on US growth charts. These changes were correlated with hemoglobin (Hgb) concentration and with energy expenditure (EE) measured using indirect whole-room calorimetry. Results Children with SCA progressed through puberty slower than control children. While, after 2 years, pubertal males with SCA were shorter, their annual increases in weight were not different from controls. The mean fat free mass (FFM) increments were significantly less in males and females with SCA than in control children. In males with SCA, growth in height declined over time and was significantly slower than in matched controls (P,<,0.05). Conclusion Growth delays were present during puberty in children with SCA. Decreased growth velocity in children with SCA was independently associated with decreased Hgb concentration and increased total EE. Pediatr Blood Cancer 2009;53:635,641. © 2009 Wiley-Liss, Inc. [source] Contact in the Andes: Bioarchaeology of systemic stress in colonial Mórrope, PeruAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009Haagen D. Klaus Abstract The biocultural interchange between the Eastern and Western Hemispheres beginning in the late fifteenth century initiated an unprecedented adaptive transition for Native Americans. This article presents findings from the initial population biological study of contact in the Central Andes of Peru using human skeletal remains. We test the hypothesis that as a consequence of Spanish colonization, the indigenous Mochica population of Mórrope on the north coast of Peru experienced elevated systemic biological stress. Using multivariate statistical methods, we examine childhood stress reflected in the prevalence of linear enamel hypoplasias and porotic hyperostosis, femoral growth velocity, and terminal adult stature. Nonspecific periosteal infection prevalence and D30+/D5+ ratio estimations of female fertility characterized adult systemic stress. Compared to the late pre-Hispanic population, statistically significant patterns of increased porotic hyperostosis and periosteal inflammation, subadult growth faltering, and depressed female fertility indicate elevated postcontact stress among both children and adults in Mórrope. Terminal adult stature was unchanged. A significant decrease in linear enamel hypoplasia prevalence may not indicate improved health, but reflect effects of high-mortality epidemic disease. Various lines of physiological, archaeological, and ethnohistoric evidence point to specific socioeconomic and microenvironmental factors that shaped these outcomes, but the effects of postcontact population aggregation in this colonial town likely played a fundamental role in increased morbidity. These results inform a model of postcontact coastal Andean health outcomes on local and regional scales and contribute to expanding understandings of the diversity of indigenous biological variation in the postcontact Western Hemisphere. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Late effects of early growth hormone treatment in Down syndromeACTA PAEDIATRICA, Issue 5 2010Å Myrelid Abstract Objective:, Down syndrome (DS) is associated with short stature and psychomotor delay. We have previously shown that growth hormone (GH) treatment during infancy and childhood normalizes growth velocity and improves fine motor skill performance in DS. The aim of this study was to investigate late effects of early GH treatment on growth and psychomotor development in the DS subjects from the previous trial. Design:, Twelve of 15 adolescents with DS (3 F) from the GH group and 10 of 15 controls (5 F) participated in this follow-up study. Fifteen other subjects with DS (6 F) were included as controls in anthropometric analyses. Cognitive function was assessed with the Leiter International Performance Scale-Revised (Leiter-R) and selected subtests of the Wechsler Intelligence Scale for Children, Third edition (WISC-III). The Bruininks-Oseretsky Test of Motor Proficiency, Second edition (BOT-2), was used to assess general motor ability. Results:, Although early GH treatment had no effect on final height, the treated subjects had a greater head circumference standard deviation score (SDS) than the controls (,1.6 SDS vs. ,2.2 SDS). The adolescents previously treated with GH had scores above those of the controls in all subtests of Leiter-R and WISC-III, but no difference in Brief IQ-score was seen between the groups. The age-adjusted motor performance of all subjects was below ,2 SD, but the GH-treated subjects performed better than the controls in all but one subtest. Conclusion:, The combined finding of a greater head circumference SDS and better psychomotor performance indicates that DS subjects may benefit from early GH treatment. [source] Final height after combined growth hormone and GnRH analogue treatment in adopted girls with early pubertyACTA PAEDIATRICA, Issue 11 2004T Tuvemo Background: Girls adopted from developing countries often have early or precocious puberty, requiring treatment with gonadotrophin-releasing hormone (GnRH) analogues. During such treatment, decreased growth velocity is frequent. Aim: To study whether the addition of growth hormone (GH) to GnRH analogue treatment improves final height in girls with early or precocious puberty. Methods: Forty-six girls with early or precocious puberty (age ± 9.5y) adopted from developing countries were randomized for treatment for 2,4 y with GnRH analogue, or with a combination of GH and GnRH analogue. Results: During treatment, the mean growth velocity in the GH/GnRH analogue group was significantly higher compared to the control group. Combined GH/GnRH analogue treatment resulted in a higher final height: 158.9 cm compared to 155.8 cm in the GnRH analogue-treated group. Three out of 24 girls (13%) in the combined group and nine of the 22 girls (41%) treated with GnRH analogue alone attained a final height below ,2 standard deviation scores (SDS). Conclusion: The difference between the two groups is statistically significant, and possibly of clinical importance. A future challenge is to identify a subgroup with clinically significant advantage of GH addition to GnRH analogue treatment. Being very short on arrival in Sweden and being short and young at start of treatment are possible indicators. [source] Knee-heel length measurements in preterm infants: evaluation of a simple electronically equipped instrumentACTA PAEDIATRICA, Issue 2 2003E Engström Aim: To compare and evaluate a mini-knemometer with a simple and inexpensive electronic caliper with regard to precision, handling error (technical error) and estimation of growth velocity. Methods: Thirty-five prematurely born infants, with a median gestational age of 29 (range 24,33) wk and a median birthweight of 960 (range 480,2480) g, were measured on 409 different occasions with both instruments. On each occasion, five independent readings were made. Results: There was no significant difference in precision between the two instruments, when measuring growth velocity over a 4 wk period (median 0.41, range 0.10,0.59 mm d,1). The handling error in this study, calculated as the mean standard deviation, was 0.36 (SD 0.18, coefficient of variation 0.38%) mm for the simple electronic caliper and 0.59 mm for the mini-knemometer. Short-term growth was detectable within 2 d when growth velocity was normal. Conclusion: Longitudinal measurement of lower leg length is a gentle and useful complementary method for assessing growth in preterm infants. An inexpensive electronic caliper is well suited for routine use in clinical practice, with measurements taken once or twice a week. [source] Effects on growth velocity and growth factors in a group of short children given vitamin A supplement: a pilot studyACTA PAEDIATRICA, Issue 6 2002Article first published online: 2 JAN 200 No abstract is available for this article. [source] | |||||||||||||