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

Pour suivre mon actualité ou me contacter : sur Facebook.

L’acide aspartique augmente t’il ou diminue t’il la sécrétion de testostérone?

08/04/2015 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge et Etudes sur les boosters sexuels et la sexualité

 

Three and six grams supplementation of d-aspartic acid in resistance trained men
Geoffrey W Melville       Journal of the International Society of Sports Nutrition 2015, 12:15

Although abundant research has investigated the hormonal effects of d-aspartic acid in rat models, to date there is limited research on humans. Previous research has demonstrated increased total testosterone levels in sedentary men and no significant changes in hormonal levels in resistance trained men. It was hypothesised that a higher dosage may be required for experienced lifters, thus this study investigated the effects of two different dosages of d-aspartic acid on basal hormonal levels in resistance trained men and explored responsiveness to d-aspartic acid based on initial testosterone levels.

Methods

Twenty-four males, with a minimum of two years’ experience in resistance training, (age, 24.5 ± 3.2 y; training experience, 3.4 ± 1.4 y; height, 178.5 ± 6.5 cm; weight, 84.7 ± 7.2 kg; bench press 1-RM, 105.3 ± 15.2 kg) were randomised into one of three groups: 6 g.d−1 plain flour (D0); 3 g.d−1 of d-aspartic acid (D3); and 6 g.d−1 of d-aspartic acid (D6). Participants performed a two-week washout period, training four days per week. This continued through the experimental period (14 days), with participants consuming the supplement in the morning. Serum was analysed for levels of testosterone, estradiol, sex hormone binding globulin, albumin and free testosterone was determined by calculation.

Results

D-aspartic acid supplementation revealed no main effect for group in: estradiol; sex-hormone-binding-globulin; and albumin. Total testosterone was significantly reduced in D6 (P = 0.03). Analysis of free testosterone showed that D6 was significantly reduced as compared to D0 (P = 0.005), but not significantly different to D3. Analysis did not reveal any significant differences between D3 and D0. No significant correlation between initial total testosterone levels and responsiveness to d-aspartic acid was observed (r = 0.10, P = 0.70).

Conclusions

The present study demonstrated that a daily dose of six grams of d-aspartic acid decreased levels of total testosterone and free testosterone (D6), without any concurrent change in other hormones measured. Three grams of d-aspartic acid had no significant effect on either testosterone markers. It is currently unknown what effect this reduction in testosterone will have on strength and hypertrophy gains.

Un extrait d’huile d’olive contre le cancer!

08/04/2015 | Etudes Compléments alimentaires et Etudes Anti-âge

 

Un extrait d’huile d’olive contre le cancer!

(-)-Oleocanthal rapidly and selectively induces cancer cell death via lysosomal membrane permeabilization (LMP)

Molecular & Cellular Oncology   Accepted author version posted online: 23 Jan 2015

(-)-Oleocanthal (OC), a phenolic compound in extra virgin olive oil (EVOO), has been implicated in the health benefits associated with diets rich in EVOO. We investigated the effect of OC on human cancer cell lines in culture. Amazingly, OC induced cell death in all cancer cells examined – as rapidly as 30 minutes after treatment in the absence of serum. OC treatment of non-transformed cells suppressed proliferation, but did not cause cell death. OC induced both primary necrotic and apoptotic cell death via induction of lysosomal membrane permeabilization (LMP). We provide evidence that OC promotes LMP by inhibiting acid sphingomyelinase (ASM) activity, which destabilizes the interaction between proteins necessary for lysosomal membrane stability.

The data presented here indicates that cancer cells having fragile lysosomal membranes – as compared to non-cancerous cells – are susceptible to lysosomotropic agent-induced cell death. Therefore, targeting lysosomal membrane stabiltiy represents a novel approach to induce cancer-specific cell death.

Encore plein d’amphétamine dans les fat burner

07/04/2015 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

An amphetamine isomer whose efficacy and safety in humans has never been studied, β-methylphenylethylamine (BMPEA), is found in multiple dietary supplements
Pieter A. Cohen   Drug Testing and Analysis Article first published online: 7 APR 2015

The amphetamine isomer β-methylphenylethylamine (BMPEA) was first synthesized in the early 1930s, but its efficacy and safety in humans has not been studied. Recently, the United States Food and Drug Administration (FDA) detected BMPEA in dietary supplements labelled as containing Acacia rigidula.

Over a year after the FDA reported its findings, we analyzed Acacia rigidula dietary supplements to determine if BMPEA had been removed. Supplements were analyzed using liquid chromatography-quadrupole time-of-flight mass spectrometry. Diluted methanolic extract from each supplement was run three times and each data set obtained was analyzed using Agilent MassHunter Qualitative Analysis. The presence of BMPEA was confirmed by accurate mass, retention time and mass spectra match against a reference standard. Quantification of BMPEA was determined using an eight-point calibration curve of spiked standard to a matrix blank. Twenty-one brands of Acacia rigidula supplements were analyzed. More than half (11/21; 52.4%) of the Acacia rigidula supplement brands contained BMPEA.

The stimulant was present at quantities such that consumers following recommended maximum daily servings would consume a maximum of 93.7 mg of BMPEA per day. Consumers of Acacia rigidula supplements may be exposed to pharmacological dosages of an amphetamine isomer that lacks evidence of safety in humans. The FDA should immediately warn consumers about BMPEA and take aggressive enforcement action to eliminate BMPEA in dietary supplements.

Lien entre vitesse de la propagation de la force et l’architecture du muscle

06/04/2015 | Etudes Musculation

 

An Attempt to Bridge Muscle Architecture Dynamics and Its Instantaneous Rate of Force Development using Ultrasonography
Jizhou Li     Ultrasonics Available online 4 April 2015

Highlights

• Higher temporal resolution regarding the rate of force development (RFD), named the instantaneous rate of force development (I-RFD), is presented to describe the ability to rapidly develop muscular force.
• The proposed indirect method based ultrasonography is believed to be a promising alternative means to assess instantaneous torque output non-invasively.
• The experiment results showed there was a linear relationship between the plantar flexor torque/force output and muscle architecture dynamics.

Abstract

Muscle force output is an essential index in rehabilitation assessment or physical exams, and could provide considerable insights for various applications such as load monitoring and muscle assessment in sports science or rehabilitation therapy. Besides direct measurement of force output using a dynamometer, electromyography has earlier been used in several studies to quantify muscle force as an indirect means. However, its spatial resolution is easily compromised as a summation of the action potentials from neighboring motor units of electrode site. To explore an alternative method to indirectly estimate the muscle force output, and with better muscle specificity, we started with an investigation on the relationship between architecture dynamics and force output of triceps surae. The muscular architecture dynamics is captured in ultrasonography sequences and estimated using a previously reported motion estimation method. Then an indicator named as the dorsoventrally averaged motion profile (DAMP) is employed. The performance of force output is represented by an instantaneous version of the rate of force development (RFD), namely I-RFD.

From experimental results on ten normal subjects, there were significant correlations between the I-RFD and DAMP for triceps surae, both normalized between 0 and 1, with the sum of squares error at 0.0516 ±± 0.0224, R-square at 0.7929 ±± 0.0931 and root mean squared error at 0.0159 ±± 0.0033. The statistical significance results were less than 0.01.

The present study suggested that muscle architecture dynamics extracted from ultrasonography during contraction is well correlated to the I-RFD and it can be a promising option for indirect estimation of muscle force output.

Le NO permet-il de vivre plus longtemps?

04/04/2015 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge et Etudes sur les boosters sexuels et la sexualité

 

Le NO permet-il de vivre plus longtemps?

Artemisinin mimics calorie restriction to trigger mitochondrial biogenesis and compromise telomere shortening in mice
Da-Ting Wang​        Peer J 2015 3:e822

Calorie restriction is known to extend lifespan among organisms by a debating mechanism underlying nitric oxide-driven mitochondrial biogenesis. We report here that nitric oxide generators including artemisinin, sodium nitroprusside, and L-arginine mimics calorie restriction and resembles hydrogen peroxide to initiate the nitric oxide signaling cascades and elicit the global antioxidative responses in mice.

The large quantities of antioxidant enzymes are correlated with the low levels of reactive oxygen species, which allow the down-regulation of tumor suppressors and accessory DNA repair partners, eventually leading to the compromise of telomere shortening. Accompanying with the up-regulation of signal transducers and respiratory chain signatures, mitochondrial biogenesis occurs with the elevation of adenosine triphosphate levels upon exposure of mouse skeletal muscles to the mimetics of calorie restriction.

In conclusion, calorie restriction-triggered nitric oxide provides antioxidative protection and alleviates telomere attrition via mitochondrial biogenesis, thereby maintaining chromosomal stability and integrity, which are the hallmarks of longevity.

Suivre les recommandations nutritionnelles du gouvernement rend gras!

02/04/2015 | Etudes Perte de poids et Etudes Anti-âge

 

C’est à la fois drôle et triste. D’un autre coté, je ne pense pas qu’on leur ait demandé de manger plus et de ne plus faire de sport

Statistical review of US macronutrient consumption data, 1965–2011: Americans have been following dietary guidelines, coincident with the rise in obesity
Evan Cohen       Nutrition Volume 31, Issue 5, May 2015, Pages 727–732

Highlights
• Americans have been adhering to federal dietary guidelines for the past 40 y.
• Fat consumption by US adults decreased from 45% to 34% between 1965 and 2011.
• Carbohydrate consumption increased from 39% to 51% over this same period.
• There is a high correlation between the change in diet and the rise of obesity.
• The percentage of overweight adults has increased from 42% to 66% since 1971.


For almost 50 y, the US National Health and Nutrition Examination Survey (NHANES) has measured the caloric consumption, and body heights and weights of Americans. The aim of this study was to determine, based on that data, how macronutrient consumption patterns and the weight and body mass index in the US adult population have evolved since the 1960s.

Methods
We conducted the first comprehensive analysis of the NHANES data, documenting how macronutrient consumption patterns and the weight and body mass index in the US adult population have evolved since the 1960s.

Results
Americans in general have been following the nutrition advice that the American Heart Association and the US Departments of Agriculture and Health and Human Services have been issuing for more than 40 y: Consumption of fats has dropped from 45% to 34% with a corresponding increase in carbohydrate consumption from 39% to 51% of total caloric intake. In addition, from 1971 to 2011, average weight and body mass index have increased dramatically, with the percentage of overweight or obese Americans increasing from 42% in 1971 to 66% in 2011.

Conclusions
Since 1971, the shift in macronutrient share from fat to carbohydrate is primarily due to an increase in absolute consumption of carbohydrate as opposed to a change in total fat consumption. General adherence to recommendations to reduce fat consumption has coincided with a substantial increase in obesity.

Finastéride contre la chute des cheveux: manque de sérieux dans les études

02/04/2015 | Etudes Anti-âge et Etudes sur les boosters sexuels et la sexualité

 

Adverse Event Reporting in Clinical Trials of Finasteride for Androgenic Alopecia
A Meta-analysis FREE ONLINE FIRST
Steven M. Belknap             JAMA Dermatol. Published online April 01, 2015.

Importance Two meta-analyses conclude that finasteride treatment of androgenic alopecia (AGA) is safe but do not assess quality of safety reporting.

Objective To assess safety reporting for clinical trial reports of finasteride for AGA.

Data Sources MEDLINE, ClinicalTrials.gov, and a clinical data repository for an academic medical center.

Study Selection Published clinical trial reports for finasteride treatment of AGA.

Data Extraction and Synthesis For each trial, we assessed quality of adverse event reporting, extracted the number and type of adverse events in treatment and placebo groups, and assessed duration of safety evaluation and adequacy of blinding. Two observers independently extracted the data; differences were resolved by consensus. We assessed generalizability in a large cohort of men prescribed finasteride, 1.25 mg/d or less, by assessing for eligibility in the finasteride-AGA pivotal trials.

Main Outcomes and Measures Quality was assessed as adequate, partially adequate, inadequate, or no events reported. We used funnel plots of the hazard ratio to assess bias.

Results Of 34 clinical trials, none had adequate safety reporting, 19 were partially adequate, 12 were inadequate, and 3 reported no adverse events. Funnel plots were asymmetric with a bias toward lower odds ratio for sexual adverse effects, suggesting systematic underdetection. No reports assessed adequacy of blinding, 18 (53%) disclosed conflicts of interest, and 19 (56%) received funding from the manufacturer. Duration of drug safety evaluation was 1 year or less for 26 of 34 trials (76%). Of 5704 men in the clinical data repository who were treated for AGA with finasteride, 1.25 mg/d or less, for AGA, only 31% met inclusion criteria for the pivotal trials referenced in the manufacturer’s full prescribing information and 33% took finasteride for more than 1 year.

Conclusions and Relevance Available toxicity information from clinical trials of finasteride in men with AGA is very limited, is of poor quality, and seems to be systematically biased. In a cohort of men prescribed finasteride for routine treatment of AGA, most would have been excluded from the pivotal studies that supported US Food and Drug Administration approval for AGA. Published reports of clinical trials provide insufficient information to establish the safety profile for finasteride in the treatment of AGA.

Page 1 sur 164 pages  1 2 3 >  Last »