Cliquez sur les images pour acquérir mes livres : frais de port gratuits et envoi rapide.

Pour suivre mon actualité ou me contacter : sur Facebook.

Les muscles peuvent aussi produire de l’EPO

18/06/2016 | Etudes sur les hormones et Etudes Anti-âge

 

Skeletal Muscle Erythropoietin Expression Is Responsive to Hypoxia and Exercise
BAKER, JEFF           Medicine & Science in Sports & Exercise: July 2016 - Volume 48 - Issue 7 - p 1294–1301

Purpose: Erythropoietin is responsible for regulating the growth and development of red blood cells. Reports conflict on whether skeletal muscle is able to produce erythropoietin and release it into circulation and if exercise affects this. We set out to determine how erythropoietin is regulated in skeletal muscle and to determine whether skeletal muscle-derived erythropoietin can stimulate erythropoiesis.

Methods: Using an in vitro approach, we exposed proliferating and differentiated skeletal muscle cells to various forms of exercise-induced physiological stimuli and measured erythropoietin gene expression. To understand if skeletal muscle cells were able to stimulate erythropoiesis, independent of other cell types found in skeletal muscle, we used myoblast-conditioned media to treat bone marrow and to measure erythropoiesis through flow cytometry. We also measured erythropoietin expression and hypoxia in mice subjected to an exercise protocol designed to induce skeletal muscle oxygen stress.

Results: Hypoxia increased erythropoietin expression in C2C12 myoblasts, myotubes, and primary myoblasts in vitro by 50% to 130%. Bone marrow treated with media conditioned with hypoxic myoblasts for 24 h increased the number of Ter-119-positive cells by 32%. An erythropoietin-neutralizing antibody prevented this increase. Compared with unexercised controls, exhaustive exercise increased skeletal muscle HIF1α levels by 50% and HIF2α levels by 20%. Moreover, exercised skeletal muscle erythropoietin expression was 70% higher.

Conclusion: These results demonstrate that skeletal muscle produces erythropoietin in a hypoxia and HIF-dependent manner and that hypoxia-treated muscle is capable of stimulating erythropoiesis in vitro.

Traitement long terme de GH: l’incidence sur la mortalité est digne de la roulette russe

15/06/2016 | Etudes sur les hormones et Etudes Anti-âge

 

Mortality and cancer incidence among patients treated with recombinant growth hormone during childhood in Israel
Clinical Endocrinology 13 June 2016     Carmit Libruder

Context

The inconclusive evidence regarding long term safety of rhGH therapy underlines the need for long-term large-scale cohorts.
Objective

To assess long term mortality and cancer incidence among patients treated with rhGH during childhood in Israel.
Design: A population-based cohort study.
Setting: Data were retrieved from a national register established in 1988. Mortality data from the national population register were available through December 31st, 2014. Data on cancer incidence from the national cancer registry were available through December 31st, 2012.

Participants: All patients ≤19 years approved for rhGH treatment during 1988-2009 were included. Patients were assigned to three risk categories, according to the underlying condition leading to growth disorder.
Main Outcome Measures

All-cause mortality and cancer incidence rates were calculated, based on person-years at risk. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated, using the Israeli general population as a reference.

Results

Included were 1,687 patients assigned to the low risk category and 440 patients assigned to the intermediate risk category. In the low risk category, all-cause mortality and cancer incidence were lower than expected (SMR 0.81, 95% CI 0.22-2.08 and SIR 0.76, 95% CI 0.09-2.73).
In the intermediate risk category, all-cause mortality and cancer incidence were significantly higher than expected (SMR 4.05, 95% CI 1.62-8.34 and SIR 4.52, 95% CI 1.22-11.57).

Conclusions

No increased risk of mortality or cancer incidence was found in low risk patients treated with rhGH during childhood. Patients with prior risk factors were at higher risk of both mortality and cancer.

Les études le prouvent: le banquier mange trop!

15/06/2016 | Etudes Perte de poids

 

Apports alimentaires spontanés et profils métaboliques dans un groupe de 30 banquiers du grand Tunis
Nutrition Clinique et Métabolisme Volume 30, Issue 2, June 2016, Pages 111–112     C. Amrouche

Introduction et but de l’étude

L’adoption de nouveaux modes de vie malsains comme l’augmentation de la consommation de plats préparés hors ménage, dont la composition est souvent inconnue, des aliments riches en graisse, en sucre et à forte densité énergétique, contraste avec une réduction concomitante du niveau d’activité physique des individus ce qui entraîne l’émergence de la pandémie d’obésité.

Le but de ce travail est d’évaluer les apports spontanés d’un groupe de banquiers travaillant dans le grand Tunis, rechercher les éventuelles anomalies métaboliques dans ce groupe d’individus et entreprendre des actions de prévention nutritionnelle et hygiénique personnalisées afin d’améliorer le profil sanitaire de ces fonctionnaires.

Matériel et méthodes

Il s’agit d’une étude transversale descriptive concernant 30 individus adultes âgés de 24 à 55 ans, qui travaillent dans des établissements bancaires du grand Tunis. Cette étude a été réalisée sur une période de deux mois allant du 1er février au 31 mars 2015.

Résultats

L’âge moyen de nos fonctionnaires était de 39 ± 9,21 ans. Le surpoids a touché plus des trois quarts (73,30 %) de la population étudiée et l’obésité était notée dans 20 % des cas. Seuls 20 % de notre groupe ne consommaient que des repas préparés à domicile et 60 % prenaient leurs petits déjeuners et déjeuners hors ménage. Les apports caloriques moyens du petit déjeuner, du déjeuner et totaux des fonctionnaires s’alimentant exclusivement à domicile étaient inférieurs à ceux des fonctionnaires prenant deux repas hors ménage mais sans différence statistiquement significative. Lorsque le petit déjeuner est pris hors ménage, ses apports caloriques moyens sont significativement plus importants que lorsqu’il est pris à domicile (p = 0,024). L’IMC et le tour de taille moyens des fonctionnaires s’alimentant exclusivement à domicile sont significativement inférieurs à ceux des fonctionnaires prenant deux repas hors ménage (respectivement p = 0,003 ; p = 0,002). La glycémie à jeun augmentait significativement en fonction de l’IMC chez les hommes de notre étude (p = 0,034) qui représentaient 46,7 % de la population étudiée.

Conclusion

Les professionnels de la banque avec la vie sédentaire qu’ils mènent et des apports alimentaires hypercaloriques surtout si hors ménage devraient bénéficier de programmes adaptés de dépistage et de prise en charge de l’obésité.

Nano-encapsulation: le futur des vitamines?

09/06/2016 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

Nano-encapsulation as a promising approach for targeted delivery and controlled release of vitamins
Iman Katouzian     Trends in Food Science & Technology Volume 53, July 2016, Pages 34–48

Highlights
• Importance of vitamin nanoencapsulation is compared to microencapsulation.
• Microencapsulation techniques applied in vitamins are discussed.
• Nanoencapsulation methods and nanocarriers applied in vitamins are reviewed.
• Factors influencing the release rate of vitamins are highlighted.
• Safety and risk evaluation issues are analyzed.

Background

Vitamins are bioactive molecules necessary for human health, which are sensible to degradation. During consumption, the bioavailability of these compounds might be limited due to structure break-down and low absorption. Today, nanoencapsulation can be a promising approach for targeted delivery of vitamins and protecting these bioactive components against destructive environment during processing and delivery. Regarding the benefits of utilizing nanotechnology in the food sector, safety aspects of these tiny carriers should also be clarified as this technology develops. Due to the possible negative effects of nanomaterials, several agencies have legislated regulatory policies to prevent potential harms to the consumers, which are underlined in this article.

Scope and approach

Nanoencapsulation-based technologies are a unique and novel field of investigation in the food and pharmaceutical industry with benefits, such as higher bioavailability, high shelf-stability and controlled release of active compounds. This review highlights recent works on these techniques and advances made in nanoencapsulation of lipophilic and hydrophilic vitamins, safety issues and health risks regarding the consumption of these products, which opens new horizons in food technology and nutrition with possibilities of commercialization in the near future.

Key findings and conclusions

Recently, considerable progresses are being carried out in the field of food nanoencapsulation involving novel nanovehicles to encapsulate vitamins. Nanofibers and nanohydrogels are some examples of efficient and modern nanocarriers. Overall, the vitamins encapsulated within nanovehicles are considered safe since they are mostly produced from food components, meanwhile more studies should be performed regarding the safety issues of nanodelivery of vitamins. In near future, it is assumed that nanoencapsulated vitamins will be broadly applied the in the food and beverage products.

Corrélation entre un niveau bas de sélénium et l’arthrose

08/06/2016 | Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge

 

The Association Between Serum Selenium Levels with Rheumatoid Arthritis
Na Yu, Fang Han         Biological Trace Element Research July 2016, Volume 172, Issue 1, pp 46-52

There are conflicting reports on the correlation between serum selenium (Se) levels with rheumatoid arthritis (RA). Through a meta-analysis approach, the aim of the present study is to clarify the relationship between serum Se levels with RA. We searched literatures that met our predefined criteria in PubMed, ScienceDirect, and OVID published as of September 2015. Ten eligible articles with 14 case–control studies involving 716 subjects were identified.

Overall, pooled analysis indicated that subjects with RA had lower serum levels of Se than the healthy controls (standardized mean difference (SMD) = −1.347, 95 % confidence interval (CI) = [−1.872, −0.823], p < 0.001). Further subgroup analysis indicated that subjects with RA had lower serum Se levels than healthy controls in Europe (SMD = −1.063, 95 % CI = [−1.571, −0.556], p < 0.001) and Asia (SMD = −3.254, 95 % CI = [−4.687, −1.821], p < 0.001) but not in USA (SMD = −0.322, 95 % CI = [−0.657, 0.012], p = 0.059). The serum Se levels were lower in RA than healthy controls measured by graphite furnace atom absorption spectrometry (GFAAS) (SMD = −1.026, 95 % CI = [−1.522, −0.530], p < 0.001), electrothermal absorption spectrometry (EAS) (SMD = −1.197, 95 % CI = [−2.373, −0.020], p < 0.05), flame atomic absorption spectrophotometry (FAAS) (SMD = −0.681, 95 % CI = [−1.049, −0.313], p < 0.001), and inductively coupled plasma–mass spectrophotometer (ICP-MS) (SMD = −11.707, 95 % CI = [−15.189, −8.224], p < 0.001) but not by neutron activation analysis (NAA) (SMD = −0.674, 95 % CI = [−1.350, 0.003], p = 0.051).

In conclusion, this meta-analysis supports a significant association between low serum Se concentration with RA. However, this finding needs further confirmation by a trans-regional multicenter study to obtain better understanding of causal relationship between serum Se with RA of different human races or regions.

80% des suppléments européens de rhodiole sont de mauvaise qualité

27/05/2016 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge et Etudes sur les boosters sexuels et la sexualité

 

The authenticity and quality of Rhodiola rosea products
Phytomedicine Volume 23, Issue 7, 15 June 2016, Pages 754–762       Anthony Booker

Les suppléments européens de rhodiole sont de mauvaise qualité

Rhodiola rosea L. Crassulaceae, root (Golden Root, Arctic Root) is a high-value herbal medicinal product, registered in the UK for the treatment of stress-induced fatigue, exhaustion and anxiety based on traditional use and used throughout Europe as a herbal medicinal product for similar indications. Numerous unregistered supplements are also available. There are several Chinese species used in traditional Chinese medicine (TCM), including Rhodiola crenulata (Hook.f. & Thomoson) that is believed to be a common adulterant in the R. rosea value chain.

Aims

The project is embedded in a larger study aiming to investigate the diverse value chains that lead to the production of R. rosea as an herbal medicinal product or supplement. Here we focus on a comparison of the quality of the finished products and assess any phytochemical variation between products registered under the Traditional Herbal Medicine Products Directive (THMPD) and products obtained from the market without any registration (i.e. generally unlicensed supplements). Our key aim is to establish the extent of the problem in terms of adulteration of consumer products claiming to contain R. rosea (or R. crenulata).

Methods

Approximately 40 commercial products (granulated powders and extracts) were sourced from different suppliers. We analysed these samples using high performance thin layer chromatography (HPTLC), mass spectrometry (MS) and 1H NMR spectroscopy coupled with multi-variate analysis software following a method previously developed by our group for the analysis of turmeric products.

Results

We investigate the phytochemistry of the different species and assess the potential of R. crenulata as an adulterant at the end of the R. rosea value chains. The consistency of the products varies significantly. Approximately one fifth of commercial products that claimed to be R. rosea did not contain rosavin (the key reference markers used to distinguish R. rosea from related species). Moreover some products appeared not to contain salidroside, another marker compound found in other Rhodiola species. Approximately 80% of the remaining commercial products were lower in rosavin content than the registered products and appeared to be adulterated with other Rhodiola species.

Conclusions

The variation in phytochemical constituents present in Rhodiola products available to European buyers via the internet and other sources is a major cause for concern. Adulteration with different species, and other sometimes unknown adulterants, appears to be commonplace. Good quality systems and manufacturing practices, including those required under the THMPD, enable consumers to have confidence that products are authentic and meet a high specification for quality and safety.

Comment le sport endommage t’il le coeur sur le long terme?

19/05/2016 | Etudes cardio et Echauffement et blessures et Etudes Anti-âge

 

Long-term leucine supplementation aggravates prolonged strenuous exercise-induced cardiovascular changes in trained rats
Gustavo Barbosa dos Santos             Experimental Physiology 2016

Observational studies have raised concerns that prolonged strenuous exercise training may be associated with increased risk of cardiac arrhythmia and even primary cardiac arrest or sudden death. It has been demonstrated that leucine can reduce prolonged exercise-induced muscle damage and accelerate the recovery process. The aim of this study was to investigate the effects of prolonged strenuous endurance exercise on cardiovascular parameters and biomarkers of cardiac injury in trained adult male rats and assess the use of leucine as an auxiliary substance to prevent the likely cardiac adverse effects caused by strenuous exercise. Twenty-four male Wistar rats were randomly allocated to receive a balanced control diet (18% protein) or a leucine-rich diet (15% protein plus 3% leucine) for 6 weeks. The rats were submitted to 1 hour of exercise, 5 d.wk−1 for 6 wk. Three days after the training period rats were submitted to swimming exercises until exhaustion and cardiac parameters were assessed.

Exercising until exhaustion significantly increased cardiac biomarker levels and cytokines, glycogen content and inhibited protein synthesis signaling also led to cardiac electrical disturbances. When combined with exercise, leucine supplementation led to further increases in the aforementioned parameters and also significant increase in blood pressure and protein degradation signaling. We report, for the first time, that leucine supplementation not only does not prevent cardiac fatigue symptoms, but may also aggravate prolonged strenuous exercise-induced cardiovascular disturbances in trained rats. Furthermore, we find that exercising until exhaustion can cause cardiac electrical disturbances and cardiac myocyte damage.

Page 1 sur 183 pages  1 2 3 >  Last »