Skeletal maturity and bone growth in twins

Heritability of skeletal maturity and bone growth is discussed on the basis of intrapair resemblances (correlation coefficients) and differences (revised percent deviations) in mono- and dizygotic twins and random pairs of unrelated children. A series of 1072 radiographs of the right hand and wrist in 63 male and 70 female pairs of monozygotic twins, and 25 male and 21 female pairs of dizygotic twins aged 12 to 18 years studied longitudinally in Tokyo were used. Skeletal maturity based on the TW2 age suggests higher heritability than bone growth based on the second metacarpal dimensions. In the latter, length has higher heritability than width and cortical thickness. A dosage effect seems to be suggested in width and some indices in the second metacarpal, but is not confirmed in skeletal maturation.     

Radiographic Evaluation of Appendicular Skeletal Maturation in the Common Marmoset (Callithrix jacchus)

The thoracic appendicular skeletal development of five common marmosets was monitored radiographically at weekly intervals from 1 day to 94 weeks of age and the times of appearance and fusion of 47 ossification centers were recorded. A range and average age for the appearance and fusion of each ossification center were calculated and compared to data available for the rhesus monkey and man.     

Skeletal maturity of Japanese children in Western Kyushu

This paper describes the skeletal maturity status of Japanese children in Western Kyushu and its variation within Japanese populations. Hand-wrist skeletal maturity was assessed by the Tanner-Whitehouse (1975) (TW2) method from radiographs of 500 boys and 485 girls aged from 4 to 15 years. Western Kyushu children showed retarded skeletal maturity scores (RUS, carpals, and 20-bone) under the age of 12 years for boys and 10 years for girls, and thereafter they were advanced in relation to the British standard. Within Japanese populations the present sample showed delayed maturity compared to Tokyo children, but was close to that of Sapporo children throughout the age range studied. However, the expected effect of secular trend suggested skeletal maturity more advanced for Tokyo children and somewhat advanced one for Sapporo children compared to that of Western Kyushu children.     

Ossification in the hand and foot of the macaque (Macaca nemistrina). I. General features.

The appearance of the secondary centers of ossification was investigated in hand and foot radiographs of 112 fetal and neonatal Macaca nemestrina and a maturational index calculated using a scoring system that differentiated between the initial and later stages of ossification. Cumulative incremental curves of skeletal maturation, constructed by plotting the maturational indices against gestational age, demonstrated three distinct periods of ossification: the First Acceleration when primary centers appear, the Plateau, and the Second Acceleration when the secondary centers ossify. Similar curves are constructed for human prenatal and postnatal ossification. The results are also compared with those reported for M. mulatta, and the bases of the observed differences are discussed. Compared with other primates, the fetal and neonatal macaque shows a developmental precocity which may be an ontogenetic adaptation to the socioecological setting of terrestrial life.     

Ovarian development associated with first maturity in three Antarctic channichthyid species

It has been known for some time that yolk deposition and final ovarian maturation were prolonged processes for many Antarctic fish. The adolescent phase in three species of channichthyid has been studied, based on an extensive series of samples over five seasons. Samples were obtained during a series of abundance estimation surveys on the shelf around South Georgia. Fish were measured, and sex and maturity stage determined from macroscopic examination of the gonads. It was found that for female Champsocephalus gunnari and Pseudochaenichthys georgianus the adolescent phase lasts <1 year but in Chaenocephalus aceratus it lasts for nearly 4 years.     

Development of the hand and wrist bones in chimpanzees

Skeletal developmental of chimpanzees was studied cross-sectionally. By application of the TW2 method, we described the skeletal development of chimpanzees and compared their skeletal development with humans'. A development pattern of chimpanzees repeated accelerations and decelerations displaying “early-juvenile trough,” “pre-adolescent peak,” “mid-adolescent trough,” and “post-adolescent peak” in incremental curves. Sex differences in skeletal development are slower development in males during infant and early juvenile phases, and greater increment around the adolescent phase in males. Females are fully mature at younger ages than males, e.g. about one and a half years. In comparison with chimpanzees, humans have such characteristics as a longer slower period of juvenile development and a shorter spurt-like adolescent fast period which ends with full maturity.     

Problems in the aging of females using the Os pubis.

The Gilbert-McKern method for aging the female Os pubis has attained popularity following Gilbert's ('73) demonstration that the McKern-Stewart male standards are not directly applicable to females. In order to assess the reliability of the method, forensic anthropologists were asked to age a set of 11 pubes of known age. There was a great deal of variability in the responses of the 23 participants. Three, four, and five different responses (out of a 6-scale system) were given for each component of each pubic bone. Only 51% of the assessments yielded age ranges which would include the known age of the specimens. Analysis of the errors showed that one of the focal problems of the Gilbert-McKern system was the difficulty in judging whether the ventral rampart was building up or breaking down.     

高寒环境实验兔骨骼肌火器伤组织病理学观察

目的:探讨高寒低温干燥自然条件下,火器伤病理组织学变化特点,为临床救治及预防冻-火器复合伤提供依据。方法:对一组实验兔,在-18℃～-22℃低温干燥自然条件下,用5.62 mm小口径手枪,距0.5cm射击双后肢,制做冻-火器复合伤模型;观察骨骼肌火器伤病理组织学改变及超微结构特征。结果:高寒低温干燥自然条件下冻-火器复合伤的病理改变,挫伤区组织以坏死为主,震动区以变性为主。提示高寒低温环境肌组织火器伤病理改变是火器与高寒低温共同引起损伤,高寒条件加剧损伤程度;而在创伤肌组织震荡区中,仍保存较多的肌性修复功能,呈现以肌巨细胞增生性为主的修复过程。结论:高寒干燥自然条件下早期脱离高寒环境,可以较好地减轻或预防冻-火器复合伤的程度。     

Height, weight, and lines of arrested growth in young Guatemalan children

A cross-sectional study of height, weight and skeletal maturity as judged from radiographs of hand and wrist, of 1,412 children under seven years of age (694 boys and 718 girls) living in rural Guatemala was performed. Height and weight were compared to standards prepared by the Institute of Nutrition of Central America and Panama (INCAP). Skeletal age was assessed by the Tanner-Whitehouse and the Greulich and Pyle methods. All x-rays were read by the senior author. The children surveyed were significantly shorter and lighter than well noruished Guatemalan children. Differences were evident by age six months and at a maximum by age five years. Both methods showed skeletal age to lag behind chronological age so that the Guatemalan rural children mature at slower rates than either the British children or the Ohio, U.S.A., children, from whom the two sets of standards were developed. Children of both sexes with radio-opaque transverse lines at the metaphysis showed a consistent tendency to be shorter than children without such lines. Boys but not girls showed similar trends for weight. In general, the data are consistent with the view that the physical development in boys is more severely retarded by an adverse environment than that of girls.     

Regulation of the Skeletal Muscle Ryanodine Receptor/Ca2+-release Channel RyR1 by S-Palmitoylation

The ryanodine receptor/Ca²⁺-release channels (RyRs) of skeletal and cardiac muscle are essential for Ca²⁺ release from the sarcoplasmic reticulum that mediates excitation-contraction coupling. It has been shown that RyR activity is regulated by dynamic post-translational modifications of Cys residues, in particular S-nitrosylation and S-oxidation. Here we show that the predominant form of RyR in skeletal muscle, RyR1, is subject to Cys-directed modification by S-palmitoylation. S-Palmitoylation targets 18 Cys within the N-terminal, cytoplasmic region of RyR1, which are clustered in multiple functional domains including those implicated in the activity-governing protein-protein interactions of RyR1 with the L-type Ca²⁺ channel Ca_V1.1, calmodulin, and the FK506-binding protein FKBP12, as well as in “hot spot” regions containing sites of mutations implicated in malignant hyperthermia and central core disease. Eight of these Cys have been identified previously as subject to physiological S-nitrosylation or S-oxidation. Diminishing S-palmitoylation directly suppresses RyR1 activity as well as stimulus-coupled Ca²⁺ release through RyR1. These findings demonstrate functional regulation of RyR1 by a previously unreported post-translational modification and indicate the potential for extensive Cys-based signaling cross-talk. In addition, we identify the sarco/endoplasmic reticular Ca²⁺-ATPase 1A and the α_1S subunit of the L-type Ca²⁺ channel Ca_V1.1 as S-palmitoylated proteins, indicating that S-palmitoylation may regulate all principal governors of Ca²⁺ flux in skeletal muscle that mediates excitation-contraction coupling.     

Changes in the motility patterns of spermatozoa from the rabbit epididymis as assessed by computer-aided sperm motion analysis

Sperm maturation in the epididymis includes changes in their potential for motility that enables spermatozoa to reach the egg and penetrate its investments. The motility characteristics of spermatozoa from the testis, the epididymis, and vas deferens of the rabbit were investigated by computer-assisted sperm analysis (CASA). Various forms of motility were displayed by sperm from different regions of the epididymis released into incubation medium Testicular sperm were motile, although nonprogressive. The maximum percentage motility was expressed by sperm in the proximal cauda epididymidis, and forward progression was developed by spermatozoa from the distal caput. Once forward progression was established, the curvilinear velocity was about the same for sperm from all regions of the tract, whereas straight-line velocity increased between the mid-corpus and cauda and paralleled the decline in lateral displacement of the head. The maintenance of motility in vitro was best maintained by sperm from the distal regions of the tract although sperm from the distal caput maintained motility better than sperm from the proximal and midcorpus regions. Analysis of the motile sperm cells revealed several types of trajectories (“irregular,” “small circular,” “large circular and arcs,” “jagged” and “straight-line”) that were analyzed by discriminant analysis using the variables generated by CASA. Accuracy of classification varied from 70% to 96%, depending on the type of track. The classification function was then applied to the changes that occurred during incubation and showed that irregular trajectories gave way to small and then large circular tracks and progressive forms as sperm matured. © 1996 Wiley-Liss, Inc.     

Nox2 Mediates Skeletal Muscle Insulin Resistance Induced by a High Fat Diet

Inflammation and oxidative stress through the production of reactive oxygen species (ROS) are consistently associated with metabolic syndrome/type 2 diabetes. Although the role of Nox2, a major ROS-generating enzyme, is well described in host defense and inflammation, little is known about its potential role in insulin resistance in skeletal muscle. Insulin resistance induced by a high fat diet was mitigated in Nox2-null mice compared with wild-type mice after 3 or 9 months on the diet. High fat feeding increased Nox2 expression, superoxide production, and impaired insulin signaling in skeletal muscle tissue of wild-type mice but not in Nox2-null mice. Exposure of C2C12 cultured myotubes to either high glucose concentration, palmitate, or H₂O₂ decreases insulin-induced Akt phosphorylation and glucose uptake. Pretreatment with catalase abrogated these effects, indicating a key role for H₂O₂ in mediating insulin resistance. Down-regulation of Nox2 in C2C12 cells by shRNA prevented insulin resistance induced by high glucose or palmitate but not H₂O₂. These data indicate that increased production of ROS in insulin resistance induced by high glucose in skeletal muscle cells is a consequence of Nox2 activation. This is the first report to show that Nox2 is a key mediator of insulin resistance in skeletal muscle.     

Clinical standards for growth in height of Belgian boys and girls,aged 2 to 18 years

The present paper presents the first clinical standard for growth in height of Belgian boys and girls, based on purely longitudinal data. Growth charts are provided with centiles of height for age along with growth curves of the typical early, average and late maturing child in the population. These new standards show the classical features of cross-sectional standards, but above that, they also provide information about the variability in individual growth patterns, as a result of variation in maturation. Average adult height is 176.6 cm (SD=6.3 cm) in boys and 163.3 cm (SD=5.7 cm) in girls. The representativity of these new standards with respect to the actual Belgian population has been by comparison with recent cross-sectional data, collected on a large number of subjects. These standards should be applied in all situations where interest lies in the evaluation of the normality of a child's growth pattern over some length of time and will therefore find their usefulness in clinical follow-up studies of growth.     

Brachymesophalangia V in Hottentot and “Cape Colored” children in Namibia (South West Africa) and South Africa

In order to determine the incidence of Brachymesophalangia V, an inspectional and metrical analysis was made of radiographs of 67 Nama-speaking Hottentots aged 2 to 17.5 years, and 210 Rehoboth Basters (in Namibia) and Cape Colored children (near Cape Town) aged 1.5 to 21 years. None of the children displayed cone-shaped epiphysis or early union, and none showed Brachymesophalangia V. It was confirmed that the incidence of Brachymesophalangia V is considerably higher in Mongoloid populations than in Caucasoid or Negroid groups, including Hottentots.     

Subcutaneous fat remodelling in Southeast Asian infants and children

Longitudinal data on 1,048 Thai children were evaluated for evidence of subcutaneous fat remodelling. Fat distribution, as defined by 100 (triceps/[triceps + subscapular]), was more pronounced in the limbs during infancy but shifted toward the trunk thereafter. Subsequent stepwise regression analysis indicated that biological age--as measured by Gruelich-Pyle bone age--and weight together explained between 0.8% and 14.5% of variance in fat distribution, with generally larger R2 values over age and for males. Relationships were curvilinear, with sex differences in slope. Path analysis supported the model that weight was a major causal agent primarily after infancy, whereas biological age had a small influence both in infancy and in late childhood. These findings indicate that trunk fat deposition is a normal feature of childhood. They also suggest that hypotheses which associate elevated trunk fatness with disorders of glucose metabolism are invalid for younger children.     

Further observations on a method for estimating hominoid dental developmental patterns

Several recent studies have concluded that early hominines resembled apes in patterns of dental ontogeny and have inferred from this conclusion that they were ape-like in other aspects of growth and development as well. Prior to their employment on fossil junveniles, the comparative methods used in these studies were not first tested for their predicitive accuracy in distinguishing modern humans from apes on the basis of proposed patterns of dental ontogeny. We find that 92% of a smaple of 48 modern children are classified as ape-like or nonhuman by the criteria employed in one of these studies and overlap entirely with fossil juvenile dental patterns. The use of these methods to characterize early hominines as “ape-like” or distinctly divergent from humans is thus shown to be unwarranted. © 1993 Wiley-Liss, Inc.     

Angiotensin Type 2 Receptor Signaling in Satellite Cells Potentiates Skeletal Muscle Regeneration

Patients with advanced congestive heart failure (CHF) or chronic kidney disease (CKD) often have increased angiotensin II (Ang II) levels and cachexia. Ang II infusion in rodents causes sustained skeletal muscle wasting and decreases muscle regenerative potential through Ang II type 1 receptor (AT1R)-mediated signaling, likely contributing to the development of cachexia in CHF and CKD. However, the potential role of Ang II type 2 receptor (AT2R) signaling in skeletal muscle physiology is unknown. We found that AT2R expression was increased robustly in regenerating skeletal muscle after cardiotoxin (CTX)-induced muscle injury in vivo and differentiating myoblasts in vitro, suggesting that the increase in AT2R played an important role in regulating myoblast differentiation and muscle regeneration. To determine the potential role of AT2R in muscle regeneration, we infused C57BL/6 mice with the AT2R antagonist PD123319 during CTX-induced muscle regeneration. PD123319 reduced the size of regenerating myofibers and expression of the myoblast differentiation markers myogenin and embryonic myosin heavy chain. On the other hand, AT2R agonist {"type":"entrez-protein","attrs":{"text":"CGP42112","term_id":"874777115","term_text":"CGP42112"}}CGP42112 infusion potentiated CTX injury-induced myogenin and embryonic myosin heavy chain expression and increased the size of regenerating myofibers. In cultured myoblasts, AT2R knockdown by siRNA suppressed myoblast differentiation marker expression and myoblast differentiation via up-regulation of phospho-ERK1/2, and ERK inhibitor treatment completely blocked the effect of AT2R knockdown. These data indicate that AT2R signaling positively regulates myoblast differentiation and potentiates skeletal muscle regenerative potential, providing a new therapeutic target in wasting disorders such as CHF and CKD.     

Analysis of Local Structure in the D2/S1–S2 Region of the Rat Skeletal Muscle Type 1 Sodium Channel Using Insertional Mutagenesis

Abstract: A reporter epitope was inserted at 11 positions in a region encompassing proposed transmembrane segments S1 and S2 in the second repeat domain (D2) of the rat skeletal muscle type 1 sodium channel. All mutations produced full-length membrane-associated protein following transfection into cultured cells, although the level of expression varied with insertion position. Characterization of cognate cRNAs for each mutation in Xenopus oocytes by two-electrode voltage clamp defined a permissive region between the proposed transmembrane regions in which these large insertions did not interfere with channel function. Two of the mutations, in which the point of insertion was within the proposed S1–S2 loop, demonstrated extracellular membrane labeling when studied either by antibody binding in oocytes or by confocal analysis following transfection into primary muscle cells. Our results define the likely boundaries of an extramembrane region linking the S1 and S2 transmembrane segments in D2 and confirm the extracellular location of this S1–S2 loop predicted by current models of channel tertiary structure.