Low fructose and low salt diets increase mitochondrial DNA in white blood cells of overweight subjects.

OBJECTIVE: To evaluate the effect of sodium and fructose restriction on mitochondrial DNA (mtDNA) content and systemic oxidative stress in a sample of overweight and pre hypertensive subjects. MATERIAL/METHODS: Data and blood samples were collected from 36 overweight and pre hypertensive patients randomly assigned to either an isocaloric (with respect to baseline) low sodium-fructose diet or an isocaloric low sodium diet. Patients were followed for 8 weeks. We measured mitochondrial DNA (mtDNA) content from peripheral blood white cells by Real-time PCR and plasma malondialdehyde (MDA) and 2,4-dinitrophenylhydrazine (DNPH) as markers of reactive oxygen species (ROS). RESULTS: Compared to baseline, at week 8 there was a continued and significant increase in mtDNA in both the low sodium diet group [2.4 vs. 13.1 (relative copy number), p<0.05] and the low sodium diet-fructose group (1.9 vs. 147.2, p<0.05). By week 8 there was a continued decrease in plasma DNPH levels in the low sodium diet group (4.6 vs. 2.6, p<0.05) and in the low sodium diet-fructose group (5.8 vs. 2.2, p<0.05). No significant differences were found with MDA. CONCLUSION: Our studies suggest that simple dietary measures such as reducing salt with or without restricting fructose can increase mtDNA and improve markers of oxidative stress.

[Scanning electronic microscopy of the myocardium: alternative technics]. / Microscopía electrónica de barrido del miocardio: técnicas alternativas.

In scanning electron microscopy (SEM) most biological specimens lack conductance of electrons, requiring of coating with conducting element, which prevent damage from the electron beam. The present study combines the use of osmium-thiocarbohydrazide-osmium (OTO) with Peldri II and hexamethyldisilazane (HMDS), as an alternative procedure to improve the image of biological specimens for SEM. We examined freeze-fractured rat's myocardium. The tissue was fixed with cacodylate buffer, followed by 2.5% glutaraldehyde in buffer. Specimens were remove and fixed for two hours at 4 degrees C. The first group of tissues were processed with standard technique, the second with OTO and Peldri II and the third was treated with OTO and HMDS. All specimens were examined in a SEM. The routine processed specimens allowed an appropriate visualization of myocytes and their subcellular elements including nucleus, myofibrils, mitochondria. Likewise tissue processed with the combination of OTO in addition HMDS and OTO plus Peldri II, allowed a high quality study. The procedure described herein may offer an alternative for the study of biological specimens by SEM.