ABSTRACT
We tested the hypothesis that reducing hydrogen ion accumulation during training would result in greater improvements in muscle oxidative capacity and time to exhaustion (TTE). Male Wistar rats were randomly assigned to one of three groups (CON, PLA, and BIC). CON served as a sedentary control, whereas PLA ingested water and BIC ingested sodium bicarbonate 30 min prior to every training session. Training consisted of seven to twelve 2-min intervals performed five times/wk for 5 wk. Following training, TTE was significantly greater in BIC (81.2 +/- 24.7 min) compared with PLA (53.5 +/- 30.4 min), and TTE for both groups was greater than CON (6.5 +/- 2.5 min). Fiber respiration was determined in the soleus (SOL) and extensor digitorum longus (EDL), with either pyruvate (Pyr) or palmitoyl carnitine (PC) as substrates. Compared with CON (14.3 +/- 2.6 nmol O(2).min(-1).mg dry wt(-1)), there was a significantly greater SOL-Pyr state 3 respiration in both PLA (19.6 +/- 3.0 nmol O(2).min(-1).mg dry wt(-1)) and BIC (24.4 +/- 2.8 nmol O(2).min(-1).mg dry wt(-1)), with a significantly greater value in BIC. However, state 3 respiration was significantly lower in the EDL from both trained groups compared with CON. These differences remained significant in the SOL, but not the EDL, when respiration was corrected for citrate synthase activity (an indicator of mitochondrial mass). These novel findings suggest that reducing muscle hydrogen ion accumulation during running training is associated with greater improvements in both mitochondrial mass and mitochondrial respiration in the soleus.
Subject(s)
Adaptation, Physiological/drug effects , Mitochondria, Muscle/physiology , Physical Conditioning, Animal/physiology , Sodium Bicarbonate/pharmacology , Animals , Body Weight/physiology , Citrate (si)-Synthase/metabolism , Diet , Drinking , Hydrogen-Ion Concentration , Male , Mitochondria, Muscle/drug effects , Mitochondria, Muscle/metabolism , Muscle Fibers, Skeletal/classification , Muscle Fibers, Skeletal/metabolism , Muscle Fibers, Skeletal/physiology , Muscle, Skeletal/cytology , Muscle, Skeletal/physiology , Oxygen Consumption/physiology , Phosphofructokinase-1/metabolism , Rats , Rats, WistarABSTRACT
Acute systemic infections may involve the heart, mostly represented by myocarditis and pericarditis. We report the case of a likely myopericarditis in an adult, leading to the diagnosis of tuberculosis infection. The clinical presentation was an acute coronary syndrome with elevated troponin Ic. An alternative diagnosis of myopericarditis was considered. Chest X-ray depicted a miliary pattern and a CT-scan demonstrated bilateral micronodules with a "tree-in-bud" pattern associated with parenchymal consolidations in the apical segment of the left upper lobe, suggesting infectious bronchiolitis. As the direct microscopic examination of the bronchial expectoration revealed the presence of Koch's bacterium, a diagnosis of a tuberculous myocarditis was likely. The clinical, electrocardiographic and CT-scan findings are shown; cardiac effects associated with tuberculosis are discussed.
Subject(s)
Acute Coronary Syndrome/diagnosis , Myocarditis/diagnosis , Tuberculosis, Cardiovascular/diagnosis , Diagnosis, Differential , Electrocardiography , Humans , Male , Middle Aged , Myocarditis/diagnostic imaging , Tomography, X-Ray Computed , Tuberculosis, Cardiovascular/diagnostic imagingABSTRACT
Acute viral infections can lead to heart inflammation, including acute myocarditis. We report the first case of myopericarditis in a young immunocompetent adult, in the context of recent Epstein-Barr virus infection. Clinical presentation was common acute pericarditis, but with risk biomarkers: high troponin I levels and multiple inflammation-compatible images on MRI. Diagnosis of myopericarditis was established, and then hospitalization was necessary. Clinical electrocardiographic settings and MRI are shown; EBV cardiac effects are discussed.
Subject(s)
Epstein-Barr Virus Infections/diagnosis , Immunocompetence/immunology , Myocarditis/diagnosis , Pericarditis/diagnosis , Adolescent , Electrocardiography/methods , Epstein-Barr Virus Infections/complications , Epstein-Barr Virus Infections/immunology , Herpesvirus 4, Human/immunology , Humans , Male , Myocarditis/etiology , Myocarditis/immunology , Pericarditis/etiology , Pericarditis/immunologyABSTRACT
This study investigated the effects of high-intensity training, with or without induced metabolic alkalosis, on lactate transporter (MCT1 and MCT4) and sodium bicarbonate cotransporter (NBC) content in rat skeletal muscles. Male Wistar rats performed high-intensity training on a treadmill 5 times/wk for 5 wk, receiving either sodium bicarbonate (ALK-T) or a placebo (PLA-T) prior to each training session, and were compared with a group of control rats (CON). MCT1, MCT4, and NBC content was measured by Western blotting in soleus and extensor digitorum longus (EDL) skeletal muscles. Citrate synthase (CS) and phosphofructokinase (PFK) activities and muscle buffer capacity (betam) were also evaluated. Following training, CS and PFK activities were significantly higher in the soleus only (P < 0.05), whereas betam was significantly higher in both soleus and EDL (P < 0.05). MCT1 (PLA-T: 30%; ALK-T: 23%) and NBC contents (PLA-T: 85%; ALK-T: 60%) increased significantly only in the soleus following training (P < 0.01). MCT4 content in the soleus was significantly greater in ALK-T (115%) but not PLA-T compared with CON. There was no significant change in protein content in the EDL. Finally, NBC content was related only to MCT1 content in soleus (r = 0.50, P < 0.01). In conclusion, these results suggest that MCT1, MCT4, and NBC undergo fiber-specific adaptive changes in response to high-intensity training and that induced alkalosis has a positive effect on training-induced changes in MCT4 content. The correlation between MCT1 and NBC expression suggests that lactate transport may be facilitated by NBC in oxidative skeletal muscle, which may in turn favor better muscle pH regulation.
