Size Of Internal Organs Research Articles

Evaluating local tolerance and toxic effects of Endoforce Phyto feed additive based on laboratory animals

During import substitution, feed additives are increasingly being used, including the most effective strains of spore-forming aerobic bacteria families of the genus Bacillus subtilis, capable of revealing the genetic potential of animals. No oedema and erythema were detected when determining the local tolerance of the Endoforce Phyto feed additive on the rabbit skin. The values of physiological parameters remained normal. Conjunctival instillation of the investigational product also did not lead to deterioration in the functions of the eye unit mucous membranes and the body's functional state. A single feeding of the Endoforce Phyto feed additive at a dose many times higher than the recommended one did not lead to the death of laboratory animals or changes in behavioural reactions and physiological state, which confirmed the absence of its acute toxicity. After 90 days of determining chronic toxicity in rodents of all experimental groups, an increase in the number of erythrocytes and haemoglobin was noted: in control – by 7.2 and 8.0%, in the 1st experimental group – by 10.8 and 13.9%, in the 2nd experimental one – by 13.3 and 11.1%, in the 3rd experimental one – by 12.7 and 20.7%, respectively, compared to the baseline values. This confirmed the best body oxygenation in the rats of the experimental groups. Within the follow-up period, an increase in the total protein content in the animals of the experimental groups from 57.03 g/l to 67.30-69.82 g/l and in individuals of the control one from 68.90 to 71.33 g/l compared to the primary screening data was registered. In contrast, the activity of such enzymes as alkaline phosphatase decreased in the control by 3.3 times, and in the experimental groups – only by 1.7-1.8 times. Comparable values of biochemical parameters in rats of the experimental and control groups confirm the absence of a negative impact of the studied feed additive on the parameters of protein, carbohydrate and lipid metabolism. In the results of the rat autopsy, no pathological changes in colour, consistency and size of internal organs were registered.

Sex-dependent differences in behavioral and immunological responses to antibiotic and bacteriophage administration in mice.

The problem of antibiotic resistance is a global one, involving many industries and entailing huge financial outlays. Therefore, the search for alternative methods to combat drug-resistant bacteria has a priority status. Great potential is seen in bacteriophages which have the natural ability to kill bacterial cells. Bacteriophages also have several advantages over antibiotics. Firstly, they are considered ecologically safe (harmless to humans, plants and animals). Secondly, bacteriophages preparations are readily producible and easy to apply. However, before bacteriophages can be authorized for medical and veterinary use, they must be accurately characterized in vitro and in vivo to determinate safety. Therefore, the aim of this study was to verify for the first time the behavioral and immunological responses of both male and female mice (C57BL/6J) to bacteriophage cocktail, composed of two bacteriophages, and to two commonly used antibiotics, enrofloxacin and tetracycline. Animal behavior, the percentage of lymphocyte populations and subpopulations, cytokine concentrations, blood hematological parameters, gastrointestinal microbiome analysis and the size of internal organs, were evaluated. Unexpectedly, we observed a sex-dependent, negative effect of antibiotic therapy, which not only involved the functioning of the immune system, but could also significantly impaired the activity of the central nervous system, as manifested by disruption of the behavioral pattern, especially exacerbated in females. In contrast to antibiotics, complex behavioral and immunological analyses confirmed the lack of adverse effects during the bacteriophage cocktail administration. The mechanism of the differences between males and females in appearance of adverse effects, related to the behavioral and immune functions, in the response to antibiotic treatment remains to be elucidated. One might imagine that differences in hormones and/or different permeability of the blood-brain barrier can be important factors, however, extensive studies are required to find the real reason(s).

Influence of reduced dietary protein level on quality of pork carcasses in Windsnyer pigs

To promote the sustainable production of local pigs, their dietary protein requirements need to be determined. Meat production from these pigs when fed on appropriate diets, coupled with their adaptability to climatic extremes and disease and parasite challenges, could be of huge benefit to the pork industry. The objective of the study was to determine the carcass traits, primary pork cuts, and internal organ weights of pigs fed decreasing dietary protein levels. Thirty, slow-growing, Windsnyer male pigs were randomly allocated to six dietary treatments in a complete randomized design. There were five replications for each of the six treatments. Dietary crude protein levels in the six experimental diets were 193, 174, 154, 135, 116, and 97 g/kg, respectively. The diets were formulated to contain similar net energy levels of ~9.5 MJ/kg. Lysine, methionine, threonine, and tryptophan levels were the same for all diets. A two week adaptation was followed by an 8w feeding phase. At slaughter, pigs had an average weight of ~39.13±0.85 kg. Pigs were humanely slaughtered at the end of feeding period to determine carcass characteristics, primary pork cuts, and internal organ size. A negative linear relationship was observed between protein levels and cooler shrink. There was a positive linear relationship between protein level and dressing percentage, cooler shrink, and shoulder fat. There was a quadratic relationship between dietary protein level and shoulder fat, ham diameter, P2(3) backfat depth, and kidney weight. The thickness of dorsal fat at the last rib, the thickness of back fat, and the width of back fat at P2(2) increased linearly as protein level decreased. The reduction in dietary protein level had an influence on carcass traits, primal pork cuts, and internal organs in slow-growing Windsnyer pigs. A reduction in dietary protein level below 116 g/kg compromised ham diameter, P2(3) width of back fat thickness, shoulder fat, and kidney weight.

A high-throughput study of visceral organs in CT-scanned pigs

It has been debated whether intensive selection for growth and carcass yield in pig breeding programmes can affect the size of internal organs, and thereby reduce the animal’s ability to handle stress and increase the risk of sudden deaths. To explore the respiratory and circulatory system in pigs, a deep learning based computational pipeline was built to extract the size of lungs and hearts from CT-scan images. This pipeline was applied on CT images from 11,000 boar selection candidates acquired during the last decade. Further, heart and lung volumes were analysed genetically and correlated with production traits. Both heart and lung volumes were heritable, with h2 estimated to 0.35 and 0.34, respectively, in Landrace, and 0.28 and 0.4 in Duroc. Both volumes were positively correlated with lean meat percentage, and lung volume was negatively genetically correlated with growth (rg = − 0.48 ± 0.07 for Landrace and rg = − 0.44 ± 0.07 for Duroc). The main findings suggest that the current pig breeding programs could, as an indirect response to selection, affect the size of hearts- and lungs. The presented methods can be used to monitor the development of internal organs in the future.

The evaluation of protease enzyme effectivenes in broiler chicken diet containing jack bean seed (Canavalia ensiformis) with different protein level toward internal organ size

This study was conducted with the intention of evaluating the use of the protease enzyme in broiler feed containing jack bean seed (Canavalia ensiformis) with the different levels of protein towards the internal organs of broiler chicken starter. Bird samples used were 24 broilers of the male lohmann strain taken from 120 chickens. The study design used was a factorial completely randomized design (FCRD) with 2 factors treatment and 3 replications (each replication used 2 samples of bird). The first factor was the level of protein (CP 22% and CP 19.5%) and the second factor was the use of enzymes (non-protease and protease). Data were analyzed by using analysis of variance (ANOVA). The result showed that the use of low protein levels in broiler feed containing jack bean seed significantly (P <0.05) increased the percentage of pancreatic weights but could be improved by the use of protease enzymes. Levels of protein treatment did not significantly affect the percentage of heart, liver and bile weights. The use of protease enzymes significantly (P <0.05) decreased the percentage of pancreatic and bile weights but did not significantly affect the percentage of liver and heart weights.

Larger guts and faster growth in mice selected for high basal metabolic rate.

Postnatal growth in birds and mammals is the time of highest vulnerability and relatively high energy demands and therefore shapes the organisms' future outcomes. Several different factors might impose limitations on growth in juveniles, one of them being the efficiency of the digestive process and size of the gastrointestinal tract. We tested the gut size-growth rate relationship using a unique experimental model-mice from a selection experiment designed to produce two lines with divergent levels of basal metabolic rate (BMR): the high BMR (H-BMR) and low BMR (L-BMR) line types. These lines differ with respect to not only BMR, but also correlated traits-internal organ size and food intake. Applying a cross-fostering design and a thermoregulatory burden imposed by shaving the mothers, we demonstrated that the mass of intestine strongly affected the growth rate, with the H-BMR pups having larger intestines and growing faster, and with reduced growth rate of pups of both lines nursed by shaved L-BMR mothers. Our study also provides a functional link between high growth rate of neonates and high BMR of adults, partly reflecting metabolic costs of maintenance of their guts.

A comparative analysis of the relationship between stature and ultrasound dimensions of internal organs in adolescents

The aim of the study was a comparative characteristic of the size of internal organs according to ultrasonography data in subjects with various deviations in stature, determined using international standardized norms. Materials and methods. The stature was measured in 93 adolescents, aged 13 to 17 years. Based on the measurements, the Z-score of body length was calculated according to the WHO Growth Reference, 2007 and three groups were formed for comparing the sizes of internal organs: average, above average, below average. Ultrasonography data of the internal organs dimensions and thyroid gland was performed using a Toshiba Aplio 500 ultrasound scanner. Results. There were statistically significantly lower values of the liver span and the longitudinal size of the gallbladder in the examined subjects from the below average group compared to the rest of the subjects. The length of the spleen and the total volume of the thyroid gland were statistically significantly different in subjects from all three groups, with the highest values in volunteers from the above average group. A weak direct correlation was shown between the Z-score of body length and liver span, the length of the cauda of the pancreas, and the width of the spleen. An average direct statistical relationship was found between the Z-score of stature and the length of the spleen, as well as the total volume of the thyroid gland. Conclusion. To a greater extent, body length is associated with the size of the parenchymal organs with a pronounced connective tissue frame - the liver and spleen, as well as the thyroid gland due to the relationship of its volume with hormones that regulate growth and development. Clinical substantiation of the relationship between the structure of the body and internal organs opens up the possibility of creating anatomical standards that allow ultrasound morphometric assessment of internal organs, taking into account the individual characteristics of the patients body size.

Predation and competition induce variable organ size trade‐offs in larval anurans

AbstractInducible defenses allow organisms that live in variable environments to invest energy into defense when necessary. These responses are common in aquatic organisms and are particularly notable in larval anurans, which tend to develop deeper tails under sit‐and‐wait macroinvertebrate predation threat. Although trade‐offs between defense and growth have been well‐studied, trade‐offs with internal organ sizes have rarely been considered. The purpose of our study was to investigate the effects of predation and competition on trade‐offs associated with total length (body + tail), tail size and internal organ size (gut, pancreas, liver and fat body) in two larval anurans, red‐eyed treefrogs (Agalychnis callidryas) and gray treefrogs (Hyla versicolor). In two separate experiments, we reared larvae in outdoor mesocosms with and without competition in the presence and absence of a caged predator. We subsampled larvae from each mesocosm and measured tail and internal organ sizes. Both competition and predation exerted strong effects on total length and morphology, although each experiment produced unique results. Competition increased gut size in both species, supporting a previously reported trade‐off between gut and tail size. Competition also reduced total length in both experiments: Gray treefrogs balanced total length with lipid deposition, and red‐eyed treefrogs favored total length at the expense of lipid reserves. Predation threat elicited an increase in tail depth but a reduction in tail muscle size in gray treefrogs, which may have allowed larvae to maintain pancreas size and total length. Conversely, red‐eyed treefrogs developed larger tails with more muscle area, allocating resources in a way that sacrificed both liver and pancreas size, as well as total length. Although the specific tail response was different, both species prioritized larger guts over tail modifications when faced with both competition and predation, as large gut sizes were maintained in competitive environments even when predators were present.

Partial replacement of soybean products with canola meal in indigenous chicken diets: size of internal organs, carcass characteristics and breast meat quality

While the use of canola meal (CM) as an alternative to soybean meal in broiler diets is well-documented, there is no information on the utility of this valuable by-product for slow-growing indigenous chickens. This study was, therefore, conducted to evaluate the effects of partially replacing soybean products in a chicken grower diet with graded levels of CM on carcass characteristics, relative organ sizes and meat quality in Potchefstroom Koekoek (PK) cockerels. A total of 175 PK cockerels (342.6 ± 15.2 g body weight, 5 wk old) were randomly allocated to 25 pens. Five isonitrogenous and isoenergetic grower diets containing 0, 3.75, 6.25, 8.75, and 17.5% of CM were then randomly allocated to the pens (experimental units). After 12 wk of feeding, chickens were slaughtered to measure carcass traits, size of internal organs and meat quality traits. There were no effects of graded levels of CM on carcass weights. Wing weight increased quadratically [y = 6.27(±0.23) + 0.23 (±0.063) x–0.009 (±0.0003) x2; R2 = 0.28] in response to incremental levels of dietary CM. Drumstick, vertebrae, liver, and small intestine weights linearly increased (P < 0.05) in response to incremental levels of dietary CM. Redness (a*), initial meat pH (pHo), and shear force linearly increased (P < 0.05) but lightness (L*) and water holding capacity decreased with an increase in CM inclusion levels. However, there were no significant linear and quadratic trends for yellowness (b*), ultimate pH (pHu), drip loss, and cooking loss in response to incremental levels of CM. There were also significant quadratic trends for mineral contents of the meat with the exception of iron (Fe). It can be concluded that inclusion of CM in place of soybean products had no negative impact on carcass traits, organ size and meat quality traits of indigenous PK chickens.

Effect of Dietary Aspergillus Xylanase on Nutrient Digestibility and Utilization, Growth Performance and Size of Internal Organs in Broiler Chickens Offered Maize-Soybean Meal Based-Diets

Effect of Dietary Aspergillus Xylanase on Nutrient Digestibility and Utilization, Growth Performance and Size of Internal Organs in Broiler Chickens Offered Maize-Soybean Meal Based-Diets

Constitutional diversity in the dimensions of internal organs of teenagers

The anatomical dimensions of the internal organs are relatively stable and constitutionally determined. The connection between the somatotype and the size of the internal organs in adolescents - boys and girls - remains virtually unexplored. So, the purpose of this work is to compare the size of the internal organs separately in the group of young men and girls with lepto-, meso-and hypersome somatotype. The study involved 421 teenagers aged from 13 to 17 years: 225 boys and 196 girls. Their somatotypes were determined according to the patented method of V.A. Melnik, I.I. Salivon, N.I. Polina, and the sizes of abdominal organs and thyroid gland were determined using ultrasound morphometry. Their comparisons revealed the mosaic distribution of differences in the size of internal organs in children with different types of constitution. The authors discussed possible reasons of this difference: a methodological error in visualizing the size of internal organs, the influence of thyroid hormones, general biological and evolutionary factors, and the effect of narrow (in terms of gender and age) selection of the subjects. Thus, an orientation towards the constitutional features of the organism as a factor influencing the results of ultrasound examination of internal organs should be optional until the mechanisms and structure of these features are clarified in detail.

The effect of gender on survival for hemodialysis patients: Why don't women live longer than men?

Women in the general population have a survival advantage over men, but this advantage is not sustained in end-stage kidney disease (ESKD) patients treated by hemodialysis. To understand why gender may affect survival we need to understand confounders which may affect dialysis practices. The current paradigm is to prescribe hemodialysis to achieve a target dialyzer urea clearance adjusted to total body water volume (Kt/Vurea ). Estimated glomerular filtration calculated from serum creatinine is often used to determine when patients start dialysis; as creatinine generation rates are lower in women, this may potentially result in a lead time bias with male patients starting dialysis earlier than females. When hemodialysis dose is scaled to total body water (Kt/Vurea ) women receive shorter dialysis session times. Scaling dialysis for body surface area may be more appropriate since urea generation (a surrogate for uremic toxin production) depends upon resting energy expenditure (ie, cellular metabolism) which reflects internal organ sizes. Resting energy expenditure is proportionally greater for smaller people. Women are generally smaller than men and as such have smaller sized internal organs. However, when comparing individuals, then internal organ size is best adjusted for using body surface area, not body water. The shorter, resultant dialysis session also results in lower middle molecule clearances, increases fluid removal rates and the risk of intra-dialytic hypotension; the latter potentially results in earlier loss of residual renal function. Observational studies report that the association between survival and dialyzer Kt/Vurea is improved after adjustment for body surface area, or energy expenditure. These studies also demonstrated that the conventional prescription of hemodialysis based on current Kt/Vurea targets leads to less treatment delivered to women. These multiple consequences of the generally smaller size of women compared with men may account for the unexpectedly higher relative mortality for women. As such, prospective studies investigating alternative scaling parameters are required to confirm that increasing dialysis treatments for women improves survival.

Research on thorax impact injury of children at different ages based on finite element models

The pediatric cadaver impact experiments were reconstructed using the validated finite element(FE) models of the 3-year-old and 6-year-old children. The effect of parameters, such as hammer size, material parameters and thorax anatomical structure characteristics, on the impact mechanical responses of 3-year-old and 6-year-old pediatric thorax was discussed by designing reasonable finite element simulation experiments. The research results showed that the variation of thorax contact peak force for 3-year-old group was far larger than that of 6-year-old group when the child was impacted by hammers with different size, which meant that 3-year-old child was more sensitive to hammer size. The mechanical properties of thoracic organs had little influence on the thorax injury because of the small difference between 3-year-old and 6-year-old child in this research. During the impact, rib deformation led to different impact location and deformation of internal organs because the 3-year-old and 6-year-old children had different geometrical anatomical structures, such as different size of internal organs. Therefore, the injury of internal organs in the two groups was obviously different. It is of great significance to develop children finite element models with high biofidelity according to its real anatomical structures.

МОРФОФИЗИОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА МОЛОДИ ОСЕТРОВЫХ РЫБ, ВЫРАЩЕННОЙ НА РЫБОВОДНЫХ ЗАВОДАХ АСТРАХАНСКОЙ ОБЛАСТИ

The article focuses on the study of changeability of morphological and physiological characteristics of 850 specimens of beluga ( Huso huso ) and sturgeon ( Acipenser gueldenstaedtii ) juveniles obtained at the Ikryaninskiy and Bertyulskiy sturgeon hatcheries in the Astrakhan region. There was determined weight of the body, heart, liver and spleen, as well as the relative mass of these organs - cardiosomatic, hepatosomatic indices and index of a spleen. Sturgeon juveniles were studied within 47-127 days, beluga juveniles within 40-116 days. Certain tendency was noted: cardiosomatic index decreased with aging in both sturgeon and beluga, i.e. the relative weight of the heart in ontogenesis changes inversely to the body weight, which corresponds to literature data. Comparison of the dynamics of the liver relative weight in sturgeon and beluga juveniles showed that it coincides at two segments: maximum raise to 50-60ths day from the birth and a gradual decrease in older juveniles. The value of spleen index in juveniles of both types rose with aging. It was found in the course of the study that the size of internal organs could change, getting smaller under unfavorable factors, in particular, when juveniles suffer from the lack of feeds. In such circumstances the dynamics of developing main internal organs drastically slows down, which reflects on physiological adequacy (quality) of juveniles. Thus, morphological and physiological indicators characterizing the degree of the vitals development can be used not only for characterizing species differences of the investigated group of fish at all stages of ontogenesis, but as important factor for assessing conditions of Russian sturgeons juvenile breeding and the degree of morphological and physiological maturity of the juveniles before releasing into the natural water body.

Gender differences in the normative dimensions of internal organs of 17-years teenagers with differentsomatotypic characteristics

Individualization of approaches in preventive and clinical medicine requires individualization of normative indexes for the protocols in measurement of dimensions of internal organs. At the same time the constitutional principle for the establishment of personal protocols for supersonic morphometry of liver, gall bladder, spleen, pancreatic and thyroid glands are discussed. At the same time the age quantitative age and gender group differences remain unsufficiently studied. The purpose of the study was the investigation of specific constitutionally-dependent differences in the size of internal organs in concern with their possible somatotypic correlates. 49 female and 52 male 17-years old teenagers were studied during regular prophylactic medical inquiry using somatotypic identification and supersonic morphometry of the pancreatic and thyroid glands, liver, gall bladder, spleen, lenic and portal veins. The study revealed statistically significant larger size of liver and gall bladder in leptosomic and mesosomic males in comparison to the females of corresponding somatic types. In addition, mesososomic males possessed increased lumens of splenic and portal veins together with increased dimensions of pancreas and spleen. The reported data s can be used in clinical practice for prevention of erroneous conclusions about hyper- or hypertrophy of internal organs. The results of the study give opportunities for the establishment of anatomical standards of morphometric measurement of internal organs in concern with constitutional characteristics. The revealed somatotypic correlations can serve as markers of individual morphometric characteristics of internal organs.

Physiological and Life-History Plasticity in a Harvestman Species: Contrasting Laboratory with Field Data

Phenotypic plasticity is defined as the ability of an organism to produce different phenotypes in response to changes in internal or external environmental conditions. Experimental modification of animal diets has been widely used to study phenotypic plasticity in physiological and life-history traits. Here we compared the data from a previous experiment, conducted in a harvestman species, that was aimed to evaluate the effect of diet quality on maintenance costs (standard metabolic rate), growth rate, internal organ size (visceral mass) and fecundity (clutch mass and egg number), with new data obtained from field (mark—recapture) specimens. We assumed that of the two experimental diets tested before, animals in the field would probably consume the one of intermediate quality (i.e. have a generalist omnivorous diet), and then, we predicted that field animals should exhibit intermediate values for both physiological and life-history traits. We found that field animals and animals consuming a high quality diet showed a greater growth rate than animals consuming a poor quality diet. In addition, animals consuming a high quality diet showed a larger clutch mass than both field animals and animals consuming a poor quality diet, which, in turn, was related to higher maintenance costs. Our results illustrate how animals adopt different life history strategies according to the quality of the diet that is available, which is correlated with phenotypic adjustments at the anatomical and physiological levels.

Understanding evolutionary variation in basal metabolic rate: An analysis in subterranean rodents

Understanding how evolutionary variation in energetic metabolism arises is central to several theories in animal biology. Basal metabolic rate (BMR) –i.e., the minimum rate of energy necessary to maintain thermal homeostasis in endotherms– is a highly informative measure to increase our understanding, because it is determined under highly standardized conditions. In this study we evaluate the relationship between taxa- and mass-independent (residual) BMR and ten environmental factors for 34 subterranean rodent species. Both conventional and phylogenetically informed analyses indicate that ambient temperature is the major determinant of residual BMR, with both variables inversely correlated. By contrast, other environmental factors that have been shown to affect residual BMR in endotherms, such as habitat productivity and rainfall, were not significant predictors of residual BMR in this group of species. Then, the results for subterranean rodents appear to support a central prediction of the obligatory heat model (OHM), which is a mechanistic model aimed to explain the evolution of residual BMR. Specifically, OHM proposes that during the colonization of colder environments, individuals with greater masses of metabolically expensive tissues (and thus with greater BMR) are favored by natural selection due to the link between greater masses of metabolically expensive tissues and physiological capacities. This way, natural selection should establishes a negative correlation between ambient temperature and both internal organ size and residual BMR.

Brain size and thermoregulation during the evolution of the genus Homo

Several hypotheses have been proposed to explain the evolution of an energetically costly brain in the genus Homo. Some of these hypotheses are based on the correlation between climatic factors and brain size recorded for this genus during the last millions of years. In this study, we propose a complementary climatic hypothesis that is based on the mechanistic connection between temperature, thermoregulation, and size of internal organs in endothermic species. We hypothesized that global cooling during the last 3.2 my may have imposed an increased energy expenditure for thermoregulation, which in the case of hominids could represent a driver for the evolution of an expanded brain, or at least, it could imply the relaxation of a negative selection pressure acting upon this costly organ. To test this idea, here we (1) assess variation in the energetic costs of thermoregulation and brain maintenance for the last 3.2 my, and (2) evaluate the relationship between Earth temperature and brain maintenance cost for the same period, taking into account the effects of body mass and fossil age. We found that: (1) the energetic cost associated with brain enlargement represents an important fraction (between 47.5% and 82.5%) of the increase in energy needed for thermoregulation; (2) fossil age is a better predictor of brain maintenance cost than Earth temperature, suggesting that (at least) another factor correlated with time was more relevant than ambient temperature in brain size evolution; and (3) there is a significant negative correlation between the energetic cost of brain and Earth temperature, even after accounting for the effect of body mass and fossil age. Thus, our results expand the current energetic framework for the study of brain size evolution in our lineage by suggesting that a fall in Earth temperature during the last millions of years may have facilitated brain enlargement.

Role of Osteocyte-derived Insulin-Like Growth Factor I in Developmental Growth, Modeling, Remodeling, and Regeneration of the Bone

The osteocyte has long been considered to be the primary mechanosensory cell in the bone. Recent evidence has emerged that the osteocyte is also a key regulator of various bone and mineral metabolism and that its regulatory effects are in part mediated through locally produced osteocyte-derived factors, such as sclerostin, receptor activator of nuclear factor-kappa B ligand (RANKL), and fibroblast growth factor (FGF)-23. Osteocytes secrete large amounts of insulin-like growth factor (IGF)-I in bone. Although IGF-I produced locally by other bone cells, such as osteoblasts and chondrocytes, has been shown to play important regulatory roles in bone turnover and developmental bone growth, the functional role of osteocyte-derived IGF-I in the bone and mineral metabolism has not been investigated and remains unclear. However, results of recent studies in osteocyte Igf1 conditional knockout transgenic mice have suggested potential regulatory roles of osteocyte-derived IGF-I in various aspects of bone and mineral metabolism. In this review, evidence supporting a regulatory role for osteocyte-derived IGF-I in the osteogenic response to mechanical loading, the developmental bone growth, the bone response to dietary calcium depletion and repletion, and in fracture repair is discussed. A potential coordinated regulatory relationship between the effect of osteocyte-derived IGF-I on bone size and the internal organ size is also proposed.

Math, Science, and Web-Based Activities to Raise Awareness about Nutrition and Obesity

Teachers can raise awareness about the increase in obesity in the United States and help students make better nutritional choices. Most health care professionals, educators, researchers, journalists, and politicians in the United States agree that obesity is a growing problem in the United States. Some experts predict that, without major changes in behavior, 75% of Americans will be overweight or obese by 2015 (Wang & Beydoun, 2007). Children are especially at risk. Between 1980 and 2006, the prevalence of obesity among children in every age group rose: from 5.0% to 12.4% for those two to five years old, from 6.5% to 17.0% for those six to eleven years old, and from 5.0% to 17.6% for those twelve to nineteen years old (Ogden & Carroll, 2010; Ogden, Carroll, & Flegal, 2008). These trends may have serious consequences for children's physical and mental health. Physical health risks associated with childhood obesity include increased chances of developing cardiovascular disease, asthma, hepatic steatosis (the fatty degeneration of the liver), and Type 2 diabetes (Dietz, 1998; Luder, Melnick, & Dimaio, 1998; Must & Anderson, 2003; Rodriguez, Winkleby, Ahn, Sundquist, & Kraemer, 2002). Childhood obesity is also associated with certain mental health issues. The psychological stress of being teased or ostracized because of obesity can cause low self-esteem in children. In a study of a nationally representative sample of 1,520 black, Hispanic, and white children, Strauss (2000) found that by the age of 13 or 14, obese boys in all subgroups and obese girls in most subgroups showed significantly lower levels of self-esteem compared with their non-obese counterparts. This has serious implications for middle grades programs, as low self-esteem in children can hinder academic performance and decrease social wellness (Swartz & Puhl, 2003). Moreover, the effects of social discrimination due to obesity upon a student's self-concept may persist well beyond early adolescence (see Parker, 2010), leaving many obese individuals with feelings of insecurity that last throughout adulthood. As the authors of F as in Fat: How Obesity Policies Are Failing in America assert: future depends on the health of our children, but we're failing them by not treating the obesity epidemic with the urgency it deserves (Trust for America's Health, 2008, p. 1). The Obama administration agrees. First Lady Michelle Obama has initiated Let's Move, a major campaign that focuses attention on the problem of childhood obesity and has the ambitious aim of solv[ing] the epidemic of childhood obesity within a generation (Obama, 2010). Middle grades educators can play a significant role in supporting this national goal and in promoting student health and wellness, as recommended by This We Believe (2010). This article provides useful information about obesity and other health-related issues and suggests some engaging, classroom-tested instructional strategies for helping students in the middle grades learn how to lead healthy lives and avoid becoming super-sized. Focusing on obesity and healthrelated issues in the middle grades It is important for young adolescents to focus on physical development because their own bodies are undergoing dramatic developmental changes (Strahan, L'Esperance, & Van Hoose, 2009). Young adolescents experience significant physical development, including increased height, weight, and internal organ size (Manning, 2002; Scales, 1991, 2003). They also negotiate erratic and uncomfortable changes in muscular and skeletal growth (Kellough & Kellough, 2009). During this stage, the fusing of three bones in the tailbone area of the body, a process called ossification, causes many students to experience discomfort as this skeletal transformation increases pressure on the sciatic nerve. This developmental characteristic may help explain the difficulty some young adolescents have sitting still or staying in their seats during class (Strahan, L'Esperance, & Van Hoose, 2009). …