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Quelles interactions entre la caféine et la taurine?

16/04/2014 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

Effect of taurine and potential interactions with caffeine on cardiovascular function
Amino Acids May 2014, Volume 46, Issue 5, pp 1147-1157   Stephen W. Schaffer

The major impetus behind the rise in energy drink popularity among adults is their ability to heighten mental alertness, improve physical performance and supply energy. However, accompanying the exponential growth in energy drink usage have been recent case reports and analyses from the National Poison Data System, raising questions regarding the safety of energy drinks. Most of the safety concerns have centered on the effect of energy drinks on cardiovascular and central nervous system function. Although the effects of caffeine excess have been widely studied, little information is available on potential interactions between the other active ingredients of energy drinks and caffeine. One of the active ingredients often mentioned as a candidate for interactions with caffeine is the beta-amino acid, taurine. Although taurine is considered a conditionally essential nutrient for humans and is thought to play a key role in several human diseases, clinical studies evaluating the effects of taurine are limited. However, based on this review regarding possible interactions between caffeine and taurine,

we conclude that taurine should neutralize several untoward effects of caffeine excess.

In agreement with this conclusion, the European Union’s Scientific Committee on Food published a report in March 2003 summarizing its investigation into potential interactions of the ingredients in energy drinks. At the cardiovascular level, they concluded that “if there are any interactions between caffeine and taurine, taurine might reduce the cardiovascular effects of caffeine.” Although these interactions remain to be further examined in humans, the physiological functions of taurine appear to be inconsistent with the adverse cardiovascular symptoms associated with excessive consumption of caffeine–taurine containing beverages.

FIBO 2014: New Free Motion’s machines

14/04/2014 | Machines de musculation

 

Quels rôles de la masse osseuse dans la régulation de la glycémie?

14/04/2014 | Etudes sur les hormones et Etudes Perte de poids et Etudes Anti-âge

 

Insulin, osteoblasts, and energy metabolism: why bone counts calories
J. Clin. Invest.124(4): 1465-1467 (2014).    Ryan C. Riddle

Recent studies have demonstrated that insulin stimulates bone cells to produce and activate osteocalcin, an endocrine hormone that increases the efficiency of glucose metabolism through its actions on the pancreas and other peripheral tissues. In this issue of the JCI, Wei and colleagues directly explore the contribution of insulin signaling in osteoblasts to the disturbances in whole-body glucose metabolism associated with a high-fat diet. In mice fed a high-fat diet, increased uptake of saturated fatty acids by the osteoblast accelerates the ubiquitination and degradation of the insulin receptor. In this setting, impairments in osteoblast insulin signaling reduce serum levels of undercarboxylated osteocalcin, which in turn exacerbate insulin resistance in muscle and white adipose tissue. These findings underscore the importance of insulin-responsive skeletal cells as components of a newly appreciated endocrine network critical for regulating global energy homeostasis.


Bone-specific insulin resistance disrupts whole-body glucose homeostasis via decreased osteocalcin activation
Jianwen Wei           J Clin Invest. 2014;124(4):1781–1793. doi:10.1172/JCI72323.

Insulin signaling in osteoblasts has been shown recently to contribute to whole-body glucose homeostasis in animals fed a normal diet; however, it is unknown whether bone contributes to the insulin resistance that develops in animals challenged by a high-fat diet (HFD). Here, we evaluated the consequences of osteoblast-specific overexpression of or loss of insulin receptor in HFD-fed mice. We determined that the severity of glucose intolerance and insulin resistance that mice develop when fed a HFD is in part a consequence of osteoblast-dependent insulin resistance. Insulin resistance in osteoblasts led to a decrease in circulating levels of the active form of osteocalcin, thereby decreasing insulin sensitivity in skeletal muscle. Insulin resistance developed in osteoblasts as the result of increased levels of free saturated fatty acids, which promote insulin receptor ubiquitination and subsequent degradation. Together, these results underscore the involvement of bone, among other tissues, in the disruption of whole-body glucose homeostasis resulting from a HFD and the involvement of insulin and osteocalcin cross-talk in glucose intolerance. Furthermore, our data indicate that insulin resistance develops in bone as the result of lipotoxicity-associated loss of insulin receptors.

Des médoc dans des suppléments pour maigrir US

14/04/2014 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

FDA Analysis Prompts Recall of Several Weight Loss Products

New Life Nutritional Center, New York, NY, is recalling all lots of “Super Fat Burner capsules, Maxi Gold capsules and Esmeralda softgels” to the user level after FDA analysis revealed the products contain undeclared active pharmaceutical ingredients: sibutramine, phenolphthalein or a combination of both sibutramine and phenolphthalein.
 
Similarly, Toms River, NJ-based Pure Edge Nutrition, LLC is voluntarily recalling one lot of each: Bella Vi Insane Bee Pollen Capsules, Bella Vi BTrim Ultimate Boost, Bella Vi BTrim Max, Bella Vi Extreme Accelerator, Bella Vi Insane Amp’d, and two lots of Bella Vi Amp’d Up to the consumer level. The products were also found to contain undeclared sibutramine or a combination of both sibutramine and phenolphthalein through FDA laboratory analyses.
 
Sibutramine is an appetite suppressant that was withdrawn from the U.S. market in October 2010 due to increased risk of seizures, heart attacks, arrhythmia and strokes.

Phenolphthalein is an ingredient previously used in over-the-counter laxatives, but because of concerns of carcinogenicity, it is not currently approved for marketing in the U.S. These undeclared ingredients make these products unapproved new drugs for which safety and efficacy have not been established.
 
At this time no illnesses or injuries have been reported to New Life Nutritional Center or Pure Edge Nutrition in connection with these products.
 
New Life Nutritional Center’s products are used as weight loss aids and are packaged in 30 capsule bottles. All lots of these products are being recalled.

Le psoas-iliaque: Combien de tendons?

14/04/2014 | Musculation des abdominaux et Musculation des quadriceps et Echauffement et blessures

 

Anatomic Variance of the Iliopsoas Tendon
Am J Sports Med April 2014 vol. 42 no. 4 807-811   Marc J. Philippon


Background: The iliopsoas tendon has been implicated as a generator of hip pain and a cause of labral injury due to impingement. Arthroscopic release of the iliopsoas tendon has become a preferred treatment for internal snapping hips. Traditionally, the iliopsoas tendon has been considered the conjoint tendon of the psoas major and iliacus muscles, although anatomic variance has been reported.


Hypothesis: The iliopsoas tendon consists of 2 discrete tendons in the majority of cases, arising from both the psoas major and iliacus muscles.


Study Design: Descriptive laboratory study.


Methods: Fifty-three nonmatched, fresh-frozen, cadaveric hemipelvis specimens (average age, 62 years; range, 47-70 years; 29 male and 24 female) were used in this study. The iliopsoas muscle was exposed via a Smith-Petersen approach. A transverse incision across the entire iliopsoas musculotendinous unit was made at the level of the hip joint. Each distinctly identifiable tendon was recorded, and the distance from the lesser trochanter was recorded.


Results: The prevalence of a single-, double-, and triple-banded iliopsoas tendon was 28.3%, 64.2%, and 7.5%, respectively. The psoas major tendon was consistently the most medial tendinous structure, and the primary iliacus tendon was found immediately lateral to the psoas major tendon within the belly of the iliacus muscle. When present, an accessory iliacus tendon was located adjacent to the primary iliacus tendon, lateral to the primary iliacus tendon.


Conclusion: Once considered a rare anatomic variant, the finding of ≥2 distinct tendinous components to the iliacus and psoas major muscle groups is an important discovery. It is essential to be cognizant of the possibility that more than 1 tendon may exist to ensure complete release during endoscopy.


Clinical Significance: Arthroscopic release of the iliopsoas tendon is a well-accepted surgical treatment for iliopsoas impingement. The most widely used site for tendon release is at the level of the anterior hip joint. The findings of this novel cadaveric anatomy study suggest that surgeons should be mindful that more than 1 tendon may be present and require release for curative treatment.

Preptine, adropine et irisine les nouveaux peptides qui régulent nos dépenses calariques

14/04/2014 | Etudes sur les hormones et Etudes Perte de poids et Etudes Anti-âge

 

Avec toutes ces nouvelles hormones qui régulent nos dépenses énergétiques, ça devient dur de suivre!

Peptides Available online 8 April 2014

In Press, Uncorrected Proof — Note to users

 

 

Three new players in energy regulation: Preptin, adropin and irisin
Suleyma Aydin,

 


Highlights

• Preptin, adropin and irisin are produced by many peripheral tissues.
• Preptin, adropin and irisin are three new co-workers in the regulation of energy homeostasis.
• These three new co-workers hold considerable promise for the treatment of obesity.
• This review brings together the most recent information about these three co-workers.

Homeostasis of energy is regulated by genetic factors, food intake, and energy expenditure. When energy input is greater than expenditure, the balance is positive, which can lead to weight gain and obesity. When the balance is negative, weight is lost. Regulation of this homeostasis is multi-factorial, involving many orexigenic (appetite-stimulating) and anorexigenic (appetite-suppressing) peptide hormones. Peripheral tissues are now known to be involved in weight regulation and research on its endocrine characteristics proceeds apace.

Preptin with 34 amino acids (MW 3948 kDa),
adropin with 43 amino acids and a molecular weight of (4999 kDa), and
irisin with 112 amino acids (12,587 kDa), are three newly discovered peptides critical for regulating energy metabolism.

Preptin is synthesized primarily in pancreatic beta cells, and adropin mainly in the liver and brain, and many peripheral tissues.

Irisin, however, is synthesized principally in the heart muscle, along with peripheral tissues, including salivary glands, kidney and liver.

The prime functions of preptin and adropin include regulating carbohydrate, lipid and protein metabolisms by moderating glucose-mediated insulin release.

Irisin is an anti-obesitic and anti-diabetic hormone regulating adipose tissue metabolism and glucose homeostasis by converting white to brown adipose tissue.

This review offers a historical account of these discovery and function of these peptides, including their structure, and physiological and biochemical properties. Their roles in energy regulation will be discussed. Their measurement in biological fluids will be considered, which will lead to further discussion of their possible clinical value.

 

L’irisine: ce que l’on sait, ce que l’on ne sait pas?

13/04/2014 | Etudes Perte de poids et Etudes Anti-âge

 

Irisin as a muscle-derived hormone stimulating thermogenesis – A critical update
Tobias Hofmann         Peptides Volume 54, April 2014, Pages 89–100

Highlights

• Irisin was proposed to be induced by exercise and to stimulate the browning of fat.
• Irisin was suggested to be a treatment option for obesity and diabetes mellitus.
• However, results of subsequent studies were partly conflicting.
• The main function of irisin may yet to be discovered.
• Several gaps of knowledge remain to be filled (receptor, regulation, processing).

The recently described myokine, irisin is cleaved from fibronectin type III domain containing protein 5 (FNDC5) and has been proposed to be secreted upon exercise to promote the browning of beige fat cells in white adipose tissue that results in enhanced thermogenesis and increased energy expenditure. The initial studies suggested irisin as a treatment option for obesity and associated diseases such as type 2 diabetes mellitus and stimulated further research. However, the results of subsequent studies investigating the regulation of irisin by different types of exercise are partly conflicting and effects were only shown in highly selective patient populations so far. Moreover, other parameters like body weight or fat free mass were shown to influence irisin adding more complexity to the mechanisms regulating this hormone. The present review will describe the discovery of irisin, its potential role in adipose tissue-mediated thermogenesis, its regulation by exercise and lastly, discuss current controversies and highlight gaps of knowledge to be filled by future studies.

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