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Acta Paediatrica (Oslo, Norway : 1992).... Apr 2006To examine relationships among physical growth indicators and ages of achievement of six gross motor milestones in the WHO Child Growth Standards population.
AIM
To examine relationships among physical growth indicators and ages of achievement of six gross motor milestones in the WHO Child Growth Standards population.
METHODS
Gross motor development assessments were performed longitudinally on the 816 children included in the WHO Child Growth Standards. Six milestones (sitting without support, hands-and-knees crawling, standing with assistance, walking with assistance, standing alone, walking alone) were assessed monthly from 4 until 12 mo of age and bimonthly thereafter until children could walk alone or reached 24 mo. Failure time models were used 1) to examine associations between specified ages of motor milestone achievement and attained growth z scores and 2) to quantify these relationships as delays or accelerations in ages of milestone achievement.
RESULTS
Statistically significant associations were noted between ages of achievement of sitting without support and attained weight-for-age, weight-for-length and BMI-for-age z scores. An increase of one unit z score in these indicators was associated with 3 to 6 d acceleration in the respective achievement age. Statistically significant associations also were noted between various milestone achievement ages and growth when 3- or 6-mo and birth length-for-age z scores were entered jointly in the failure time models. In these analyses, one unit z-score increase in length-for-age was associated with 1 to 3 d delay in the respective achievement age.
CONCLUSION
Sporadic, significant associations were observed between gross motor development and some physical growth indicators, but these were quantitatively of limited practical significance. These results suggest that, in healthy populations, the attainment of these six gross motor milestones is largely independent of variations in physical growth.
Topics: Body Height; Body Mass Index; Body Weight; Child Development; Female; Humans; Infant; Infant, Newborn; Male; Motor Skills; Multicenter Studies as Topic; Reference Values; World Health Organization
PubMed: 16817683
DOI: 10.1111/j.1651-2227.2006.tb02380.x -
Life Sciences and Space Research 1973Chronic acceleration describes the exposure of animals to increased acceleration fields of sufficient intensity and duration to induce physiological adaptation. By... (Review)
Review
Chronic acceleration describes the exposure of animals to increased acceleration fields of sufficient intensity and duration to induce physiological adaptation. By comparing the degree of changes observed in several fields with the acceleration intensity, it is possible to derive an estimate of the biological effect of gravity. For technical reasons, such studies are limited to artificial fields produced by protracted centrifugation. Observations by various investigators indicate a fairly general response to chronic acceleration. Over the size range presented by these species (0.04-5 kg), there appears to be a direct relationship between body mass and the degree of the acceleration-induced effect (tolerable field intensity, growth repression, inhibition of fat (correction of far) deposition, etc.). However, different response patterns may obtain in homeotherms that differ significantly from this body size range.
Topics: Acceleration; Adaptation, Physiological; Animals; Body Composition; Body Constitution; Body Weight; Bone and Bones; Centrifugation; Chickens; Female; Hypergravity; Male; Muscle, Skeletal; Stress, Mechanical
PubMed: 12001952
DOI: No ID Found -
Scientific Reports May 2022The objective of this study was to characterize head biomechanics of video-recorded falls involving young children in a licensed childcare setting. Children 12...
The objective of this study was to characterize head biomechanics of video-recorded falls involving young children in a licensed childcare setting. Children 12 to < 36 months of age were observed using video monitoring during daily activities in a childcare setting (in classrooms and outdoor playground) to capture fall events. Sensors (SIM G) incorporated into headbands worn by the children were used to obtain head accelerations and velocities during falls. The SIM G device was activated when linear acceleration was ≥ 12 g. 174 video-recorded falls activated the SIM G device; these falls involved 31 children (mean age = 21.6 months ± 5.6 SD). Fall heights ranged from 0.1 to 1.2 m. Across falls, max linear head acceleration was 50.2 g, max rotational head acceleration was 5388 rad/s, max linear head velocity was 3.8 m/s and max rotational head velocity was 21.6 rad/s. Falls with head impact had significantly higher biomechanical measures. There was no correlation between head acceleration and fall height. No serious injuries resulted from falls-only 1 child had a minor injury. In conclusion, wearable sensors enabled characterization of head biomechanics during video-recorded falls involving young children in a childcare setting. Falls in this setting did not result in serious injury.
Topics: Acceleration; Biomechanical Phenomena; Body Height; Child; Child Care; Child, Preschool; Head; Humans; Infant
PubMed: 35597795
DOI: 10.1038/s41598-022-12489-7 -
Revista Da Sociedade Brasileira de... 2022The epidemic curve has been obtained based on the 7-day moving average of the events. Although it facilitates the visualization of discrete variables, it does not allow...
COVID-19 epidemic curve in Brazil: a sum of multiple epidemics, whose inequality and population density in the states are correlated with growth rate and daily acceleration. An ecological study.
BACKGROUND
The epidemic curve has been obtained based on the 7-day moving average of the events. Although it facilitates the visualization of discrete variables, it does not allow the calculation of the absolute variation rate. Recently, we demonstrated that the polynomial interpolation method can be used to accurately calculate the daily acceleration of cases and deaths due to COVID-19. This study aimed to measure the diversity of epidemic curves and understand the importance of socioeconomic variables in the acceleration, pek cases, and deaths due to COVID-19 in Brazilian states.
METHODS
Epidemiological data for COVID-19 from federative units in Brazil were obtained from the Ministry of Health's website from February 25 to July 11, 2020. Socioeconomic data were obtained from the Instituto Brasileiro de Geografia e Estatística (https://www.ibge.gov.br/). Using the polynomial interpolation methods, daily cases, deaths and acceleration were calculated. Moreover, the correlation coefficient between the epidemic curve data and socioeconomic data was determined.
RESULTS
The combination of daily data and case acceleration determined that Brazilian states were in different stages of the epidemic. Maximum case acceleration, peak of cases, maximum death acceleration, and peak of deaths were associated with the Gini index of the gross domestic product of Brazilian states and population density but did not correlate with the per capita gross domestic product of Brazilian states.
CONCLUSIONS
Brazilian states showed heterogeneous data curves. Population density and socioeconomic inequality were correlated with a more rapid exponential growth in new cases and deaths.
Topics: Acceleration; Brazil; COVID-19; Epidemics; Humans; Population Density; SARS-CoV-2
PubMed: 35239897
DOI: 10.1590/0037-8682-0118-2021 -
British Journal of Sports Medicine Feb 2011to examine the concurrent validity of the Technogym MyWellness Key accelerometer against objective and subjective physical activity (PA) measures. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
to examine the concurrent validity of the Technogym MyWellness Key accelerometer against objective and subjective physical activity (PA) measures.
DESIGN
randomised, cross-sectional design with two phases. The laboratory phase compared the MyWellness Key with the ActiGraph GT1M and the Yamax SW200 Digiwalker pedometer during graded treadmill walking, increasing speed each minute. The free-living phase compared the MyWellness Key with the ActiGraph, Digiwalker, Bouchard Activity cord (BAR) and Global Physical Activity Questionnaire (GPAQ) for seven continuous days. Data were analysed using Spearman rank-order correlation coefficients for all comparisons.
SETTING
laboratory and free-living phases.
PARTICIPANTS
sixteen participants randomly stratified from 41 eligible respondents by sex (n=8 men; n=8 women) and PA levels (n=4 low, n=8 middle and n=4 high active).
RESULTS
there was a strong association between the MyWellness Key and the ActiGraph accelerometer during controlled graded treadmill walking (r=0.91, p<0.01) and in free-living settings (r=0.73-0.76 for light to vigorous PA, respectively, p<0.01). No associations were observed between the MyWellness Key and the BAR and GPAQ (p>0.05).
CONCLUSIONS
the MyWellness Key has a high concurrent validity with the ActiGraph accelerometer to detect PA in both controlled laboratory and free-living settings.
Topics: Acceleration; Adult; Body Height; Body Mass Index; Body Weight; Cross-Sectional Studies; Equipment Design; Exercise; Female; Health Status; Humans; Male; Middle Aged; Monitoring, Ambulatory; Surveys and Questionnaires; Walking; Young Adult
PubMed: 19736173
DOI: 10.1136/bjsm.2009.062182 -
Journal of Pediatric Orthopedics 2009Disruption of the periosteum, whether traumatic or elective, has long been known to accelerate growth in the developing skeleton. However, the extent, timing, and...
BACKGROUND
Disruption of the periosteum, whether traumatic or elective, has long been known to accelerate growth in the developing skeleton. However, the extent, timing, and mechanism of the resultant increase in growth velocity (if any) remain undefined. The primary research questions were: Does periosteal resection result in a change (increase) in growth velocity of a long bone at the growth plate? When does the effect start after the resection and for how long? Finally, which of several cellular mechanisms is most likely responsible for the change in growth velocity?
METHODS
Five lambs underwent proximal tibial growth plate periosteal resection with subsequent measurement of growth velocity by implantable microtransducers or fluorochrome labeling. This former technique provided real-time growth velocity data with a resolution of about 10 microm (width of a proliferative zone chondrocyte). These measurements were accurate at up to 4 weeks postoperative, as verified by fluorochrome labeling, and radiographic measurement. Two lambs were continued on the study for an additional 3 weeks. Histomorphometric and stereological assessments of chondrocytic kinetic parameters were performed on control and experimental tibiae after euthanasia.
RESULTS
Periosteal resection increased growth velocity in every lamb, at every time point, and in a consistent and sustained manner. Histomorphometric correlation to this phenomenon indicated that the cellular basis of this acceleration was most likely the result of hypertrophic chondrocyte axial elongation rather than changes in chondrocyte proliferation, magnitude of hypertrophic chondrocytic swelling, or increased matrix production.
CONCLUSIONS
Periosteal resection creates immediate and sustained acceleration of growth resulting from axial elongation of the hypertrophic chondrocyte. Although the increase in growth velocity was consistent, the absolute magnitude of the acceleration suggests that periosteal resection be considered as an adjunct to other primary procedures. Periosteal resection may serve as a useful clinical adjunct to provide a modest growth stimulus in cases of hemihypertrophy or angular limb deformity or to counteract the growth inhibition seen when performing distraction osteogenesis.
Topics: Animals; Cell Proliferation; Chondrocytes; Fluorescent Dyes; Growth Plate; Hypertrophy; Models, Animal; Periosteum; Radiography; Sheep; Tibia; Time Factors; Transducers
PubMed: 19098649
DOI: 10.1097/BPO.0b013e3181929c71 -
Journal of Orthopaedic Research :... Aug 2022Bone regeneration and fracture healing are impaired in diabetic patients due to defective functions of associated cells. Thus, the search for molecular causes and new...
Bone regeneration and fracture healing are impaired in diabetic patients due to defective functions of associated cells. Thus, the search for molecular causes and new treatment strategies are of particular clinical relevance. We investigated the gene expression profile of bones from type 2 diabetic (db /db ) mice and wild-type (wt) mice by comparative microarray analyses before and after placing tibial defects and examined the expression of several osteogenesis- and osteoclastogenesis-related markers by quantitative real-time polymerase chain reaction. In regenerating wt bones, pathways related to, for example, inhibition of matrix metalloproteases were activated, whereas in db /db bones activation of pathways related to, for example, osteoarthritis, transforming growth factor-beta (Tgfb), or hypoxia-inducible factor 1a were detected during regeneration. We defined the Tgfb pathway as a potential therapeutic target and locally applied a single dose (0.5 µg) of the Tgfb 1, 2, and 3 neutralizing antibody 1D11 on tibial defects in db /db mice (n = 7). Seven days postoperation, histological and immunohistochemical stainings were performed. Decreased bone regeneration, osteogenic differentiation, osteoclast invasion, and angiogenesis in db /db mice were significantly restored by local 1D11 application in comparison to the phosphate-buffered saline controls. Thus, local treatment of db /db bony defects with Tgfb neutralizing antibody 1D11 might be considered a good candidate for the successful acceleration of bone regeneration.
Topics: Acceleration; Animals; Antibodies, Neutralizing; Bone Regeneration; Diabetes Mellitus; Mice; Osteogenesis; Transforming Growth Factor beta
PubMed: 34775640
DOI: 10.1002/jor.25212 -
Archives of Pediatrics & Adolescent... Dec 2010To provide estimates of normal variations in penile measurements and testicular volumes, and to establish reference ranges for clinical use.
OBJECTIVE
To provide estimates of normal variations in penile measurements and testicular volumes, and to establish reference ranges for clinical use.
DESIGN
Cross-sectional, population-based study.
SETTING
Schools, kindergartens, and child care centers in different parts of Bulgaria.
PARTICIPANTS
A population of 6200 clinically healthy white males aged 0 to 19 years.
INTERVENTIONS
The study physician chose schools, kindergartens, and child care centers randomly and examined children at random until he reached the required number. Each of the 20 age groups (age range, 0-19 years) had an equal number of males (ie, 310).
MAIN OUTCOME MEASURES
The mean (SD) values and fifth, 50th, and 95th percentiles of height (Siber Hegner anthropometer), weight (beam balance), testicular volume (Prader orchidometer), penile length (rigid tape), and penile circumference (measuring tape) from birth to 19 years of age.
RESULTS
Testes did not show any increase in size until the onset of puberty at age 11 years, whereas penile growth was gradual after birth. However, both penile and testicular development demonstrated peak growth from 12 to 16 years of age, which coincided with the maximal male pubertal growth spurt. Data indicate an earlier pubertal development for this study population than that for a similar population several decades ago. Significant differences between urban and rural populations regarding penile length were also noticed.
CONCLUSIONS
Our study provides the contemporary reference range values for height, weight, testicular volume, and penile length and circumference of males aged 0 to 19 years. Our data show that, even by the end of 20th century, there is still some acceleration of male pubertal development. For the first time are reported somatic differences in genitalia within a population between urban and rural representatives.
Topics: Adolescent; Age Factors; Body Height; Body Weight; Bulgaria; Child; Child Development; Child, Preschool; Cross-Sectional Studies; Genitalia, Male; Humans; Infant; Male; Organ Size; Reference Values; Young Adult
PubMed: 21135345
DOI: 10.1001/archpediatrics.2010.223 -
Life Sciences and Space Research 1973This brief review leads to the following conclusions: (i) Inversion or clinostat rotation of frogs' eggs demonstrated a critical period of enhanced gravity-sensitivity... (Review)
Review
This brief review leads to the following conclusions: (i) Inversion or clinostat rotation of frogs' eggs demonstrated a critical period of enhanced gravity-sensitivity prior to the first cleavage. These results were corroborated by centrifugation studies which localized the period of maximal sensitivity at approximately 20 minutes post-fertilization. (ii) Eggs of various invertebrates suspended in aqueous solution proved capable of normal development following brief ultracentrifugation. (iii) Among fly larvae, grasshopper nymphs, turtles, mice, rats and chickens, growth rates were inversely related to G-force and maximal chronic acceleration tolerated was inversely related to body size. (iv) Body composition data demonstrated the importance of separately evaluating fat and the fat-free portion of the body in studies of the effect of acceleration on growth in homeotherms. (v) The attempt to evaluate the effect of weightlessness on development of frogs' eggs in Biosatellite 2 was inconclusive for technical reasons.
Topics: Acceleration; Animals; Body Composition; Centrifugation; Embryo, Mammalian; Embryo, Nonmammalian; Female; Gravitation; Physiology, Comparative; Rotation; Space Flight; Weightlessness; Zygote
PubMed: 12001950
DOI: No ID Found -
Developmental Psychobiology Jan 1978An experiment was conducted to examine the effects of neonatal handling and hypothermia on infant physical maturation and growth and on maternal behavior in BALB/c mice....
An experiment was conducted to examine the effects of neonatal handling and hypothermia on infant physical maturation and growth and on maternal behavior in BALB/c mice. Stringent methodological and statistical controls were employed for experimenter bias and litter effects. No evidence appeared to support claims that neonatal stimulation leads to accelerated physical maturation. Alterations in maternal behavior patterns were found only immediately following hypothermia of pups. Maternal behavior did not correlate highly with offspring maturational rates, but maternal weight and age and pup birth weight were highly predictive of infant physical maturation.
Topics: Animals; Animals, Newborn; Birth Weight; Body Temperature; Body Weight; Female; Handling, Psychological; Humans; Litter Size; Male; Maternal Age; Maternal Behavior; Mice; Mice, Inbred BALB C; Pregnancy
PubMed: 564798
DOI: 10.1002/dev.420110112