160 research outputs found

    A METHOD FOR DETERMINING THE INDMDUAL SPORT TECHNIQUE IN JAVELIN

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    INTRODUCTION. The javelin throwing skill is within the movement pattern which objective is to reach the maximum velocity of human body chain free end at the release instant. It has been proved for numerous researchers that segments reach the maximum speed consecutively and beginning for the proximal segments. This one has done to think that throwing pattern is based in the energy transmission among segments. However, nobody has found until to day quantitative relations among energy exchanges which allow to establish, in an objective way, differences among throws of one subject. Also, the trunk has been considered normally like a bar, that is, no differing thorax, abdomen and pelvis. Finally, to remark that it has not been found any research which calculates the kinetic energy of segments considering them with their six degrees of freedom. Therefore, the main objective of this work will be to develop individual technique patterns based in the energy exchange among segments. This model should allow to assess the performance objectively. The methology has been based in the filming of the movement by mean two highspeed cine-camaras and the latter determination of the 3D coordinates of the body landmarks. DLT algorithm was used. Previously to the experimental phase, a theorical model was develop for the computation of human body kinetic energy. The model considers the body like a solid rigid (six degrees of freedom)system and takes like input the 3D coordinates of body markers. The model determines a local reference system in each segment and after calculates the kinetic energy of the 17 segments which define the human body (included the javelin). The kinetic energy is considered like the addition of a traslational and arotational terms. Two elite thowers were the subjects. 36 throws were analyzed. The energy increments of segments and groups of segments in the registered throws were the variables. Each subject was considered separately. RESULTS. The linear regression study confirmed the energy exchange among segments general pattern in both athletes. The discriminate analysis proved the existence of an individual pattern -mathematical model- for each thrower. The discriminate function allowed to differ objectively between good a bad throws. Also it informed about the technique used for the subject. CONCLUSIONS. A new model for calculating the kinetic energy of segments has been developed. A procedure for a quantitative determination of the individual pattern of movement in throwing, based on the using of discriminant analysis, has been developed REFERENCES. -Bartlett, R.M. y Best,R.J. (1988) The biomechanics of javeling throwing: a review. J. Sports Sci. 6(1), 1-38.-Caldwell, G.E. y Fonester, L.W. (1992)Estimates of mechanical work and energy transfers: demostration of a rigid bodypower model of the recovery leg in gait.Med. Sci. Sports Exerc. 24(12). 1396-1412.-Menzel, H.J. (1987) Transmission ofpartial momenta in javelin throw. EnBiomechanics X-6, (Editado por Jonsson,B.) Human Kinetics Publishers,Champaign, 643-647

    A PROCEDURE FOR DETERMINING THE ACCELERATION PHASE IN JAVELIN THROWING

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    Introduction. The throwing phase is the period from the moment both feet make contact with the ground to the delivery of the javelin. The majority of the authors - are in according with this phase can be divided en two parts. The second is the acceleration phase. Miller (1981) measured that the javelin gains the 50% of the his speed during the last 50 ms before the release. Ikegami (1981) considered the beginning of the acceleration phase in the named archedposition. It seems that arched position is one of the most important factor in the javelin throwing (Koltai, 1985). However, the definition of the beginning of the throwing phase -arched position- is no clear in the literature reviewed about javelin throwing. The aim of this work is to develop a quantitative way for determining the arched position Methodology. An upper arm model is used which considered the elbow joint with one degree of freedom. A Local Reference System fixed with the segment is determined for calculating the angular velocity of the upper arm. The arched position -beginning of acceleratiun phase- is defined like the instant of beginning of internal rotation of the upper arm. The experimental technique was the 3D-Cinematography with high speed cameras. The sampling frequency was 200 Hz. The DLT algoritm was used for determining the 3D coordinates of the markers. The coordinates was smoothed with Quintic Splines functions. The two best spanish thowers were the subjects of the study. 36 throwings were analyzed. Conclusions. The existence of one starting instant for the internal rotation upper arm has been confirmed. This instant determines the beginning of throwing phasearch position-. Subject A had an acceleration phase duration of 41.2 % (SD = 2. 8 %, n= 20) in relation to the throwing phase. Subject B had 45% (SD= 3.7%, n=16)

    Accelerated Postnatal Growth Increases Lipogenic Gene Expression and Adipocyte Size in Low–Birth Weight Mice

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    OBJECTIVE: To characterize the hormonal milieu and adipose gene expression in response to catch-up growth (CUG), a growth pattern associated with obesity and diabetes risk, in a mouse model of low birth weight (LBW). RESEARCH DESIGN AND METHODS: ICR mice were food restricted by 50% from gestational days 12.5–18.5, reducing offspring birth weight by 25%. During the suckling period, dams were either fed ad libitum, permitting CUG in offspring, or food restricted, preventing CUG. Offspring were killed at age 3 weeks, and gonadal fat was removed for RNA extraction, array analysis, RT-PCR, and evaluation of cell size and number. Serum insulin, thyroxine (T4), corticosterone, and adipokines were measured. RESULTS: At age 3 weeks, LBW mice with CUG (designated U-C) had body weight comparable with controls (designated C-C); weight was reduced by 49% in LBW mice without CUG (designated U-U). Adiposity was altered by postnatal nutrition, with gonadal fat increased by 50% in U-C and decreased by 58% in U-U mice (P less than 0.05 vs. C-C mice). Adipose expression of the lipogenic genes Fasn, AccI, Lpin1, and Srebf1 was significantly increased in U-C compared with both C-C and U-U mice (P less than 0.05). Mitochondrial DNA copy number was reduced by greater than 50% in U-C versus U-U mice (P = 0.014). Although cell numbers did not differ, mean adipocyte diameter was increased in U-C and reduced in U-U mice (P less than 0.01). CONCLUSIONS: CUG results in increased adipose tissue lipogenic gene expression and adipocyte diameter but not increased cellularity, suggesting that catch-up fat is primarily associated with lipogenesis rather than adipogenesis in this murine model

    Intergenerational Transmission of Glucose Intolerance and Obesity by In Utero Undernutrition in Mice

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    OBJECTIVE—Low birth weight (LBW) is associated with increased risk of obesity, diabetes, and cardiovascular disease during adult life. Moreover, this programmed disease risk can progress to subsequent generations. We previously described a mouse model of LBW, produced by maternal caloric undernutrition (UN) during late gestation. LBW offspring (F1-UN generation) develop progressive obesity and impaired glucose tolerance (IGT) with aging. We aimed to determine whether such metabolic phenotypes can be transmitted to subsequent generations in an experimental model, even in the absence of altered nutrition during the second pregnancy

    An unbiased assessment of the role of imprinted genes in an intergenerational model of developmental programming.

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    Environmental factors during early life are critical for the later metabolic health of the individual and of future progeny. In our obesogenic environment, it is of great socioeconomic importance to investigate the mechanisms that contribute to the risk of metabolic ill health. Imprinted genes, a class of functionally mono-allelic genes critical for early growth and metabolic axis development, have been proposed to be uniquely susceptible to environmental change. Furthermore, it has also been suggested that perturbation of the epigenetic reprogramming of imprinting control regions (ICRs) may play a role in phenotypic heritability following early life insults. Alternatively, the presence of multiple layers of epigenetic regulation may in fact protect imprinted genes from such perturbation. Unbiased investigation of these alternative hypotheses requires assessment of imprinted gene expression in the context of the response of the whole transcriptome to environmental assault. We therefore analyse the role of imprinted genes in multiple tissues in two affected generations of an established murine model of the developmental origins of health and disease using microarrays and quantitative RT-PCR. We demonstrate that, despite the functional mono-allelicism of imprinted genes and their unique mechanisms of epigenetic dosage control, imprinted genes as a class are neither more susceptible nor protected from expression perturbation induced by maternal undernutrition in either the F1 or the F2 generation compared to other genes. Nor do we find any evidence that the epigenetic reprogramming of ICRs in the germline is susceptible to nutritional restriction. However, we propose that those imprinted genes that are affected may play important roles in the foetal response to undernutrition and potentially its long-term sequelae. We suggest that recently described instances of dosage regulation by relaxation of imprinting are rare and likely to be highly regulated

    Expression of the Splicing Factor Gene SFRS10 Is Reduced in Human Obesity and Contributes to Enhanced Lipogenesis

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    SummaryAlternative mRNA splicing provides transcript diversity and may contribute to human disease. We demonstrate that expression of several genes regulating RNA processing is decreased in both liver and skeletal muscle of obese humans. We evaluated a representative splicing factor, SFRS10, downregulated in both obese human liver and muscle and in high-fat-fed mice, and determined metabolic impact of reduced expression. SFRS10-specific siRNA induces lipogenesis and lipid accumulation in hepatocytes. Moreover, Sfrs10 heterozygous mice have increased hepatic lipogenic gene expression, VLDL secretion, and plasma triglycerides. We demonstrate that LPIN1, a key regulator of lipid metabolism, is a splicing target of SFRS10; reduced SFRS10 favors the lipogenic β isoform of LPIN1. Importantly, LPIN1β-specific siRNA abolished lipogenic effects of decreased SFRS10 expression. Together, our results indicate that reduced expression of SFRS10, as observed in tissues from obese humans, alters LPIN1 splicing, induces lipogenesis, and therefore contributes to metabolic phenotypes associated with obesity

    Efficacy and safety of alirocumab in insulin-treated patients with type 1 or type 2 diabetes and high cardiovascular risk:Rationale and design of the ODYSSEY DM-INSULIN trial

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    Aims: The coadministration of alirocumab, a PCSK9 inhibitor for treatment of hypercholesterolaemia, and insulin in diabetes mellitus (DM) requires further study. Described here is the rationale behind a phase-IIIb study designed to characterize the efficacy and safety of alirocumab in insulin-treated patients with type 1 (T1) or type 2 (T2) DM with hypercholesterolaemia and high cardiovascular (CV) risk. Methods: ODYSSEY DM-INSULIN (NCT02585778) is a randomized, double-blind, placebo-controlled, multicentre study that planned to enrol around 400 T2 and up to 100 T1 insulin-treated DM patients. Participants had low-density lipoprotein cholesterol (LDL-C) levels at screening. ≥. 70. mg/dL (1.81. mmol/L) with stable maximum tolerated statin therapy or were statin-intolerant, and taking (or not) other lipid-lowering therapy; they also had established CV disease or at least one additional CV risk factor. Eligible patients were randomized 2:1 to 24. weeks of alirocumab 75. mg every 2. weeks (Q2W) or a placebo. Alirocumab-treated patients with LDL-C. ≥. 70. mg/dL at week 8 underwent a blinded dose increase to 150. mg Q2W at week 12. Primary endpoints were the difference between treatment arms in percentage change of calculated LDL-C from baseline to week 24, and alirocumab safety. Results: This is an ongoing clinical trial, with 76 T1 and 441 T2 DM patients enrolled; results are expected in mid-2017. Conclusion: The ODYSSEY DM-INSULIN study will provide information on the efficacy and safety of alirocumab in insulin-treated individuals with T1 or T2 DM who are at high CV risk and have hypercholesterolaemia not adequately controlled by the maximum tolerated statin therapy

    Hsp90 Inhibition Decreases Mitochondrial Protein Turnover

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    Cells treated with hsp90 inhibitors exhibit pleiotropic changes, including an expansion of the mitochondrial compartment, accompanied by mitochondrial fragmentation and condensed mitochondrial morphology, with ultimate compromise of mitochondrial integrity and apoptosis.We identified several mitochondrial oxidative phosphorylation complex subunits, including several encoded by mtDNA, that are upregulated by hsp90 inhibitors, without corresponding changes in mRNA abundance. Post-transcriptional accumulation of mitochondrial proteins observed with hsp90 inhibitors is also seen in cells treated with proteasome inhibitors. Detailed studies of the OSCP subunit of mitochondrial F1F0-ATPase revealed the presence of mono- and polyubiquitinated OSCP in mitochondrial fractions. We demonstrate that processed OSCP undergoes retrotranslocation to a trypsin-sensitive form associated with the outer mitochondrial membrane. Inhibition of proteasome or hsp90 function results in accumulation of both correctly targeted and retrotranslocated mitochondrial OSCP.Cytosolic turnover of mitochondrial proteins demonstrates a novel connection between mitochondrial and cytosolic compartments through the ubiquitin-proteasome system. Analogous to defective protein folding in the endoplasmic reticulum, a mitochondrial unfolded protein response may play a role in the apoptotic effects of hsp90 and proteasome inhibitors

    Inherent Plasticity of Brown Adipogenesis in White Fat of Mice Allows for Recovery from Effects of Post-Natal Malnutrition

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    Interscapular brown adipose tissue (iBAT) is formed during fetal development and stable for the life span of the mouse. In addition, brown adipocytes also appear in white fat depots (wBAT) between 10 and 21 days of age in mice maintained at a room temperature of 23°C. However, this expression is transient. By 60 days of age the brown adipocytes have disappeared, but they can re-emerge if the adult mouse is exposed to the cold (5°C) or treated with β3-adrenergic agonists. Since the number of brown adipocytes that can be induced in white fat influences the capacity of the mouse to resist the obese state, we determined the effects of the nutritional conditions on post-natal development (birth to 21 days) of wBAT and its long-term effects on diet-induced obesity (DIO). Under-nutrition caused essentially complete suppression of wBAT in inguinal fat at 21 days of age, as indicated by expression of Ucp1 and genes of mitochondrial structure and function based upon microarray and qRT-PCR analysis, whereas over-nutrition had no discernible effects on wBAT induction. Surprisingly, the suppression of wBAT at 21 days of age did not affect DIO in adult mice maintained at 23°C, nor did it affect the reduction in obesity or cold tolerance when DIO mice were exposed to the cold at 5°C for one week. Gene expression analysis indicated that mice raised under conditions that suppressed wBAT at 21 days of age were able to normally induce wBAT as adults. Therefore, neither severe hypoleptinemia nor hypoinsulinemia during suckling permanently impaired brown adipogenesis in white fat. In addition, energy balance studies of DIO mice exposed to cold indicates that mice with reduced adipose stores preferentially increased food intake, whereas those with larger adipose tissue depots preferred to utilize energy from their adipose stores

    The xc− cystine/glutamate antiporter: a mediator of pancreatic cancer growth with a role in drug resistance

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    The xc− cystine transporter enhances biosynthesis of glutathione, a tripeptide thiol important in drug resistance and cellular defense against oxidative stress, by enabling cellular uptake of cystine, a rate-limiting precursor. Because it is known to regulate glutathione levels and growth of various cancer cell types, and is expressed in the pancreas, we postulate that it is involved in growth and drug resistance of pancreatic cancer. To examine this, we characterised expression of the xc− transporter in pancreatic cancer cell lines, MIA PaCa-2, PANC-1 and BxPC-3, as subjected to cystine-depletion and oxidative stress. The results indicate that these cell lines depend on xc−-mediated cystine uptake for growth, as well as survival in oxidative stress conditions, and can modulate xc− expression to accommodate growth needs. Immunohistochemical analysis showed that the transporter was differentially expressed in normal pancreatic tissues and overexpressed in pancreatic cancer tissues from two patients. Furthermore, gemcitabine resistance of cells was associated with elevated xc− expression and specific xc− inhibition by monosodium glutamate led to growth arrest. The results suggest that the xc− transporter by enhancing glutathione biosynthesis plays a major role in pancreatic cancer growth, therapy resistance and represents a potential therapeutic target for the disease
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