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At least 703 records · Page 39Linked to original sources
PubMed1999

Mouse patched1 controls body size determination and limb patterning.

Hedgehog (Hh) proteins control many developmental events by inducing specific cell fates or regulating cell proliferation. The Patched1 (Ptc1) protein, a binding protein for Hh molecules, appears to oppose Hh signals by repressing transcription of genes that can be activated by Hh. Sonic hedgehog (Shh), one of the vertebrate homologs of Hh, controls patterning and growth of the limb but the early embryonic lethality of ptc1(-)(/)(-) mice obscures the roles of ptc1 in later stages of development. We partially rescued ptc1 homozygous mutant embryos using a metallothionein promoter driving ptc1. In a wild-type background, the transgene causes a marked decrease in animal size starting during embryogenesis, and loss of anterior digits. In ptc1 homozygotes, a potent transgenic insert allowed survival to E14 and largely normal morphology except for midbrain overgrowth. A less potent transgene gave rise to partially rescued embryos with massive exencephaly, and polydactyly and branched digits in the limbs. The polydactyly was preceded by unexpected anterior limb bud transcription of Shh, so one function of ptc1 is to repress Shh expression in the anterior limb bud.

Animals↗
PubMed1995

Subdivision of the Drosophila mushroom bodies by enhancer-trap expression patterns.

Phylogenetically conserved brain centers known as mushroom bodies are implicated in insect associative learning and in several other aspects of insect behavior. Kenyon cells, the intrinsic neurons of mushroom bodies, have been generally considered to be disposed as homogenous arrays. Such a simple picture imposes constraints on interpreting the diverse behavioral and computational properties that mushroom bodies are supposed to perform. Using a P[GAL4] enhancer-trap approach, we have revealed axonal processes corresponding to intrinsic cells of the Drosophila mushroom bodies. Rather than being homogenous, we find the Drosophila mushroom bodies to be compound neuropils in which parallel subcomponents exhibit discrete patterns of gene expression. Different patterns correspond to hitherto unobserved differences in Kenyon cell trajectory and placement. On the basis of this unexpected complexity, we propose a model for mushroom body function in which parallel channels of information flow, perhaps with different computational properties, subserve different behavioral roles.

Animals↗
PubMed2004

Clinal variation in body and cell size in a widely distributed vertebrate ectotherm.

Bergmann's rule states that, among conspecific populations, individuals are larger in cooler than in warmer environments as a consequence of selection related to heat conservation. Many of the most comprehensive assessments of Bergmann's rule to date have examined clinal patterns in body size among species assemblages. Our study is a more direct test of Bergmann's rule because we examine the pattern within a single, widely distributed species. We examined geographic variation in body and cell size in the spotted turtle ( Clemmys guttata). Our analysis of 818 turtles collected from the entire range (45-28 degrees N), indicated that body size increased with latitude; however, the relationship was driven by a population of large turtles at the northern extreme of the species' range. When the northern population was removed from the analyses, Bergmann's rule was not supported, and the smallest turtles occurred near the central part of the species' distribution. Recent literature has suggested that latitudinal clines in body size may simply be a physiological byproduct of the effects of temperature on cell division, resulting in larger cells, and hence larger organisms, from cooler temperatures. Measurements of the diameter of skin cells did not support the hypothesis that cell size increases with latitude and decreases with temperature in the spotted turtle, nor was there a significant relationship between body size and cell size. Our study suggests that neither Bergmann's rule nor cell size variation sufficiently explain the body size cline observed in the spotted turtle. We hypothesize that patterns in body size are related to variation in female size at maturity and reproductive cycles.

Animals↗
PubMed2004

Running wheel activity prevents hyperphagia and obesity in Otsuka long-evans Tokushima Fatty rats: role of hypothalamic signaling.

Otsuka Long-Evans Tokushima fatty (OLETF) rats lacking cholecystokinin-A receptors are hyperphagic, obese, and diabetic. Although exercise attenuates OLETF rats' obesity, the mechanisms underlying the effects of exercise are unclear. In this study, we determined the effects of running wheel activity on patterns of body weight gain, food intake, and hypothalamic gene expression. We demonstrate that voluntary running activity beginning at 8 wk of age normalized meal patterns, food intake, body weight, and plasma levels of glucose and leptin in OLETF rats. During the initial exercise period, corticotropin-releasing factor (CRF) mRNA expression was significantly elevated in the dorsomedial hypothalamus (DMH) but not in the paraventricular nucleus in both OLETF and control Long-Evans Tokushima rats. In response to long-term exercise, arcuate nucleus (Arc) neuropeptide Y (NPY), and proopiomelanocortin as well as DMH NPY and CRF mRNA expression were increased in Long-Evans Tokushima rats. In contrast, whereas exercising OLETF rats had increased Arc NPY and DMH CRF expression, Arc proopiomelanocortin and DMH NPY mRNA levels were not elevated. Finally, we demonstrate that the effects of exercise on body weight in OLETF rats were long lasting. Although food intake and body weight were increased in OLETF rats when running wheels were locked, weights did not return to those of sedentary OLETF rats. Together, these data suggest that the elevation of DMH CRF expression may mediate the short-term feeding inhibitory effects of exercise and that exercise limits the elevation of DMH NPY expression to account for the overall prevention of OLETF rats' obesity.

Animals↗
PubMed1995

Weight loss, psychological, and nutritional patterns in competitive male body builders.

There has been increasing interest in the effects of chronic dieting and of repeated cycles of weight loss and regain in athletes. The purpose of this investigation was to examine the eating and weight loss practices, nutrition, and psychological factors in 45 male body builders competing in a drug-free competition. Subjects completed a questionnaire on the morning of a body building competition to assess the weight loss and dietary history, psychological distress, reports of binge eating, and vitamin and mineral supplement usage. The subjects reported high levels of dieting, weight loss, and weight regain. The mean weight loss reported in the competitive season was 6.8 kg; the mean weight gain reported was 6.2 kg. Eighty-five percent reported gaining weight while 46% reported episodes of binge eating after competitions. Most (81.5%) reported being preoccupied with food sometimes, often, or always. Between 30 and 50% reported psychological distress when preparing for competition (anxiety, short temper, anger). A similar number (30-50%) reported using amino acid, protein, and vitamin supplements. It appears that severe dieting practices are common in the sport of competitive body building. The potential physiological, psychological, and health implications of these practices, combined with the growing popularity of body building, are of sufficient importance to warrant further attention by investigators and the body building community.

Adult↗
PubMed2006

"Mir"acles in hox gene regulation.

Micro RNAs (miRNAs) have been shown to control many cellular processes including developmental timing in different organisms. The prediction that miRNAs are involved in regulating hox genes of flies and mouse is quite a recent idea and is supported by the finding that mir-196 represses Hoxb8 gene expression. The non-coding regions that encode these miRNAs are also conserved across species in the same way as other mechanisms that regulate expression of hox genes. On the contrary, until now no homeotic phenotype, a hallmark of any hox gene mutation, had been associated with any hox miRNA. Recent work on bithorax complex miRNA (miR-iab-4-5p) shows, for the first time, that miRNAs can lead to homeotic transformation. This miRNA regulates Ultrabithorax (Ubx) and results in the transformation of haltere to wing. This study unveils a new complexity and finesse to the regulation of hox gene expression pattern that is needed for determining the anteroposterior body axis in all bilaterians.

Animals↗
PubMed2000

Expression of a novel receptor tyrosine kinase gene and a paired-like homeobox gene provides evidence of differences in patterning at the oral and aboral ends of hydra.

Axial patterning of the aboral end of the hydra body column was examined using expression data from two genes. One, shin guard, is a novel receptor protein-tyrosine kinase gene expressed in the ectoderm of the peduncle, the end of the body column adjacent to the basal disk. The other gene, manacle, is a paired-like homeobox gene expressed in differentiating basal disk ectoderm. During regeneration of the aboral end, expression of manacle precedes that of shin guard. This result is consistent with a requirement for induction of peduncle tissue by basal disk tissue. Our data contrast with data on regeneration of the oral end. During oral end regeneration, markers for tissue of the tentacles, which lie below the extreme oral end (the hypostome), are detected first. Later, markers for the hypostome itself appear at the regenerating tip, with tentacle markers displaced to the region below. Additional evidence that tissue can form basal disk without passing through a stage as peduncle tissue comes from LiCl-induced formation of patches of ectopic basal disk tissue. While manacle is ectopically expressed during formation of basal disk patches, shin guard is not. The genes examined also provide new information on development of the aboral end in buds. Although adult hydra are radially symmetrical, expression of both genes in the bud's aboral end is initially asymmetrical, appearing first on the side of the bud closest to the parent's basal disk. The asymmetry can be explained by differences in positional information in the body column tissue that evaginates to form a bud. As predicted by this hypothesis, grafts reversing the orientation of evaginating body column tissue also reverse the orientation of asymmetrical gene expression.

Animals↗
PubMed2004

Movement of the upper body and muscle activity patterns following a rapidly applied load: the influence of pre-load alterations.

Sudden loading of the spine is not only considered a risk factor for the development of low-back pain but also enables an evaluation of the stability of the spine when conducted under laboratory conditions. In the present study the upper spine was pulled in the anterior direction and the stiffness as well as activity in the erector spinae muscle was measured with different pre-tension in the erector spinae. The results showed that increased activity in the erector spinae prior to loading led to increased stiffness (stiffness coefficients from 297 Nm rad(-1) to 438 Nm rad(-1)) and a decrease in the extra neural signal input to the muscles to maintain the stability. It is therefore clear that increased tension in the erector spinae muscle will create a larger stability of the spine to anterior perturbations. However, contracting the muscles around the spine increases the load on the spinal structures. In 34% of the experiments a silent period in the electromyographic signal was present after loading in the period when the torso was moving in the anterior direction. This phenomenon is discussed.

Adaptation, Physiological↗
PubMed2007

Patterns and associations of body weight among older adults in two Asian societies.

Body weight has important health implications across the lifespan. Most recent attention has focused on the obesity epidemic that is occurring in many parts of the world. However, underweight is also a concern, particularly in less developed countries. For most health outcomes there is a curvilinear association with body weight, with underweight and overweight (compared to normal weight) being associated with a higher prevalence of chronic debilitating and life-threatening conditions and ultimately mortality. This paper uses data from two nationally-representative surveys of older adults (aged 60 and older) in the Philippines (1996) and Taiwan (1999) to assess the prevalence of underweight and overweight and examine associations between body weight and demographic, socioeconomic, and health characteristics in these populations. Older Filipinos have a modest prevalence of underweight (29.9%) and low prevalence of overweight (12.2%), whereas the reverse is observed in Taiwan (6.4 and 29.3%, respectively). Results show generally expected associations between body weight and demographic characteristics, health conditions and behaviors. We find little evidence of socioeconomic differences in body weight, except in the Philippines where higher SES is associated with a lower risk of being underweight. Implications of the results are discussed in terms of healthy weight maintenance among critical subgroups to potentially reduce the prevalence of disease and improve quality of life.

Age Factors↗
PubMed1988

Patterns of bleeding and body iron stores during the use of a levonorgestrel-releasing intracervical device.

A levonorgestrel-releasing intracervical device (LNG-ICD) was inserted in 198 women. The subjects registered bleeding and spotting days on special cards, which were analyzed after one year of treatment. Bleeding and spotting days gradually declined from sixteen during the first month to seven during the seventh month, and they remained under that level until the end of the first year. There were more days of spotting than bleeding. Eleven per cent of the subjects experienced at least 90 days non-bleeding interval during the first year of LNG-ICD use. There were no significant changes in blood hemoglobin concentrations during the first four years of LNG-ICD use. The mean serum ferritin concentration increased from 38 micrograms/l at the beginning to 97 micrograms/l at the end of the fourth year.

Adolescent↗
PubMed1976

Interindividual differences in circadian patterns of catecholamine excretion, body temperature, performance, and subjective arousal.

Interindividual differences in circadian rhythms of urinary catecholamine excretion, performance, self-ratings of arousal and oral temperature were studied in 80 subjects divided into three groups--morning-active, evening-active, and intermediate. Catecholamine excretion, body temperature, and self-ratings of arousal exhibited pronounced circadian variations. Morning-active subjects exceeded other groups in the 24 h level of adrenaline excretion but crest phases did not differ, occurring close to 13.00 h. No differences between groups were found for noradrenaline excretion. Crest phases occurred close to noon. Self-rated alertness exhibited a significantly earlier (14.12 h) crest phase for morning-active than for evening-active subjects (16.09 h). The performance did not differ between groups.

Arousal↗
PubMed2005

Theoretical study on the body form and swimming pattern of Anomalocaris based on hydrodynamic simulation.

Anomalocarid arthropod is the largest known predatory animal of middle Cambrian. Studies on Anomalocaris have been piled up in the past two decades since the first reasonable reconstruction had achieved in 1980s. Recent finding of legs beneath lobes on Parapeytoia Yunnanensis shows arthropod affinities, however, many researchers believe that it must be a powerful swimmer by the use of developed lobes. In this work, we investigate swimming behaviour of Anomalocaris in water by performing hydrodynamical calculation. As a result of simulation using moving particle method possible swimming motion of Anomalocaris is obtained. In the computer we can change the morphology from known bauplan of Anomalocaris found as fossil record. It makes us possible to discuss on the variants of Anomalocaris at the intermediate state of evolution process. Such new methodology using computer reveals how and from where Anomalocaris evolved.

Animals↗
PubMed1982

Patterns of gross fetal body movements over 24-hour observation intervals during the last 10 weeks of pregnancy.

Continuous measurements of gross fetal body movements were made with an ultrasonic real-time scanner for periods of 24 hours in 31 women. Fetuses made 0 to 130 gross fetal body movements per hour which accounted for 0% to 50% of the time. At 38 to 39 weeks' gestational age, fetuses demonstrated a peak in activity between 2100 and 0100 hours. The longest period of complete absence of gross fetal body movements was 75 minutes. Maternal meals and glucose concentrations did not influence gross fetal body movements.

Activity Cycles↗