Hypobaric live high-train low does not improve aerobic performance more than live low-train low in cross-country skiers.

Live high-train low (LHTL) using hypobaric hypoxia was previously found to improve sea-level endurance performance in well-trained individuals; however, confirmatory controlled data in athletes are lacking. Here, we test the hypothesis that natural-altitude LHTL improves aerobic performance in cross-country skiers, in conjunction with expansion of total hemoglobin mass (Hbmass , carbon monoxide rebreathing technique) promoted by accelerated erythropoiesis. Following duplicate baseline measurements at sea level over the course of 2 weeks, nineteen Norwegian cross-country skiers (three women, sixteen men, age 20 ± 2 year, maximal oxygen uptake (VO2 max) 69 ± 5 mL/min/kg) were assigned to 26 consecutive nights spent at either low (1035 m, control, n = 8) or moderate altitude (2207 m, daily exposure 16.7 ± 0.5 hours, LHTL, n = 11). All athletes trained together daily at a common location ranging from 550 to 1500 m (21.2% of training time at 550 m, 44.2% at 550-800 m, 16.6% at 800-1100 m, 18.0% at 1100-1500 m). Three test sessions at sea level were performed over the first 3 weeks after intervention. Despite the demonstration of nocturnal hypoxemia at moderate altitude (pulse oximetry), LHTL had no specific effect on serum erythropoietin, reticulocytes, Hbmass , VO2 max, or 3000-m running performance. Also, LHTL had no specific effect on (a) running economy (VO2 assessed during steady-state submaximal exercise), (b) respiratory capacities or efficiency of the skeletal muscle (biopsy), and (c) diffusing capacity of the lung. This study, showing similar physiological responses and performance improvements in the two groups following intervention, suggests that in young cross-country skiers, improvements in sea-level aerobic performance associated with LHTL may not be due to moderate-altitude acclimatization.

Plasma vitamin D levels and inflammation in the aortic wall of patients with coronary artery disease with and without inflammatory rheumatic disease.

OBJECTIVES: Vitamin D modulates inflammation, and this may explain the observed associations between vitamin D status and disorders driven by systemic inflammation, such as coronary artery disease (CAD) and inflammatory rheumatic diseases (IRDs). The aims of this study were to assess vitamin D status in patients with CAD alone and in patients with CAD and IRD, and to explore potential associations between vitamin D status and the presence of mononuclear cell infiltrates (MCIs) in the aortic adventitia of these patients. METHOD: Plasma levels of 25-hydroxyvitamin D3 [(25(OH)D3] were determined by radioimmunoassay and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] by enzyme immunoassay in the 121 patients from the Feiring Heart Biopsy Study (FHBS) who had available histology data on adventitial MCIs; 53 of these had CAD alone and 68 had CAD and IRD. RESULTS: In the crude analysis, vitamin D levels were similar in CAD patients with and without IRD. After adjustment for potential confounders, IRD was associated with an increase of 8.8 nmol/L [95% confidence interval (CI) 1.0-16.6; p = 0.027] in 25(OH)D3 and an increase of 18.8 pmol/L (95% CI 4.3-33.3; p = 0.012) in 1,25(OH)2D3, while MCIs in the aortic adventitia were associated with lower levels of 1,25(OH)2D3 (ß = -18.8, 95% CI -33.6 to -4.0; p = 0.014). CONCLUSIONS: IRD was associated with higher levels of both 25(OH)D3 and 1,25(OH)2D3. These findings argue against the hypothesis that patients with high systemic inflammatory burden (CAD+IRD) should have lower vitamin D levels than those with less inflammation (CAD only). Of note, when controlled for potential confounders, low 1,25(OH)2D3 levels were associated with adventitial aortic inflammation.

Reliable determination of training-induced alterations in muscle fiber composition in human skeletal muscle using quantitative polymerase chain reaction.

Determination of muscle fiber composition in human skeletal muscle biopsies is often performed using immunohistochemistry, a method that tends to be both time consuming, technically challenging, and complicated by limited availability of tissue. Here, we introduce quantitative reverse transcriptase polymerase chain reaction (qRT-PCR)-based Gene-family profiling (GeneFam) of myosin heavy chain (MyHC) mRNA expression as a high-throughput, sensitive, and reliable alternative. We show that GeneFam and immunohistochemistry result in similar disclosures of alterations in muscle fiber composition in biopsies from musculus vastus lateralis and musculus biceps brachii of previously untrained young women after 12 weeks of progressive strength training. The adaptations were evident as (a) consistent increases in MyHC2A abundance; (b) consistent decreases in MyHC2X abundance; and (c) consistently stable MyHC1 abundance, and were not found using traditional reference gene-based qRT-PCR analyses. Furthermore, muscle fiber composition found using each of the two approaches was correlated with each other (r = 0.50, 0.74, and 0.78 for MyHC1, A, and X, respectively), suggesting that GeneFam may be suitable for ranking of individual muscle phenotype, particularly for MyHC2 fibers. In summary, GeneFam of MyHC mRNA resulted in reliable assessment of alterations in muscle fiber composition in skeletal muscle of previously untrained women after 12 weeks of strength training.

Irisin and FNDC5: effects of 12-week strength training, and relations to muscle phenotype and body mass composition in untrained women.

PURPOSE: To investigate the effects of strength training on abundances of irisin-related biomarkers in skeletal muscle and blood of untrained young women, and their associations with body mass composition, muscle phenotype and levels of thyroid hormones. METHODS: Eighteen untrained women performed 12 weeks of progressive whole-body heavy strength training, with measurement of strength, body composition, expression of irisin-related genes (FNDC5 and PGC1α) in two different skeletal muscles, and levels of serum-irisin and -thyroid hormones, before and after the training intervention. RESULTS: The strength training intervention did not result in changes in serum-irisin or muscle FNDC5 expression, despite considerable effects on strength, lean body mass (LBM) and skeletal muscle phenotype. Our data indicate that training affects irisin biology in a LBM-dependent manner. However, no association was found between steady-state serum-irisin or training-associated changes in serum-irisin and alterations in body composition. FNDC5 expression was higher in m.Biceps brachii than in m.Vastus lateralis, with individual expression levels being closely correlated, suggesting a systemic mode of transcriptional regulation. In pre-biopsies, FNDC5 expression was correlated with proportions of aerobic muscle fibers, a relationship that disappeared in post-biopsies. No association was found between serum-thyroid hormones and FNDC5 expression or serum-irisin. CONCLUSION: No evidence was found for an effect of strength training on irisin biology in untrained women, though indications were found for a complex interrelationship between irisin, body mass composition and muscle phenotype. FNDC5 expression was closely associated with muscle fiber composition in untrained muscle.

Simplified 10-day bismuth triple therapy for cure of Helicobacter pylori infection: experience from clinical practice in a population with a high frequency of metronidazole resistance.

OBJECTIVE: To evaluate the cure rate of Helicobacter pylori infection, including the impact of in vitro metronidazole resistance (M-R), and the side effects of a simplified 10-day bismuth triple therapy in routine clinical practice. METHODS: From September 1995 to March 1996, 248 consecutive H. pylori-positive patients received 10 days of bismuth subnitrate 150 mg, oxytetracycline 500 mg, and metronidazole 400 mg, all t.id. Before treatment, upper endoscopy, including biopsy specimens for microbiological analysis and IgG serology were performed. M-R was found in 45% of females and 36% of males. At least 2 months after treatment, H. pylori status was assessed by the 14C urea breath test (n = 131), endoscopy (n = 37), urea breath test and endoscopy (n = 63), or solely by IgG serology (n = 7). Ten patients withdrew. IgG serology was performed again after 1 yr. RESULTS: H. pylori infection was cured in 205 patients: 86% by all-patients-treated analysis and 83% by intention-to-treat analysis. When patients were classified according to pretreatment metronidazole susceptibility, cure of infection was achieved in 76% of females harboring M-R strains versus 96% of those with sensitive strains (p = 0.002) and in 81% versus 88% (p = 0.34) of males with M-R versus sensitive strains, respectively. Twelve patients (5 %) had to stop treatment prematurely because of severe side effects, but eight of them were treated successfully. One case of H. pylori infection (0.6 %) was detected at 1-yr follow-up. CONCLUSIONS: Ten-day bismuth triple therapy t.i.d. was effective in curing H. pylori infection in the context of routine clinical practice. The efficacy was reduced in females harboring M-R strains.

An automated method for the determination of nortriptyline and its isomeric 10-hydroxylated metabolites in plasma by high pressure liquid chromatography.

A high pressure liquid chromatography assay for determination of the tricyclic antidepressant nortriptyline (NT) and its two major metabolites, Z- and E-10-Hydroxy-NT, in plasma is described. Sample preparation included addition of internal standard and a single step extraction procedure. Run time was approximately 14 min. with a LC-18. 5 mu 250 x 4.6 mm column, a mobile phase consisting of aqueous ammonium: methanol: acetonitrile (0.8:6.2:93, v/v), and flow of 1.3 ml/min. NT, Z- and E-10-OH-NT, amitriptyline, Z- and E-10-OH-AT and the internal standard desipramine, were adequately separated within this time span. In our laboratory, the assay has been employed mainly for pharmacokinetic and toxicologic studies in experimental animals at relatively high concentrations.

Identification of 3-oxodicarboxylic acids in human urine.

Gas chromatography-mass spectrometry has been used to detect a series of 3-oxodicarboxylic acids in human urine as their corresponding dimethyl ester trimethylsilyl enol ethers. 3-Oxohexanedioic acid, 3-oxooctanedioic acid and 3-oxodecanedioic acid were demonstrated to be normal urine constituents. Increased amounts of these acids were excreted after ingestion of decanedioic acid. These findings support the hypothesis that dicarboxylic acids are degraded by ordinary beta-oxidation.

Absolute configuration of 3-hydroxyadipic acid in human urine.

A method involving derivatization and combined gas chromatography--mass spectrometry has been developed to separate the enantiomers of 3-hydroxyadipic acid. By combining this method with asymmetric synthesis of the same acid, it has been shown that 3-hydroxyadipic acid excreted in urine consists of at least 95% of the L-enantiomer. This finding supports the hypothesis that dicarboxylic acids are degraded by ordinary beta-oxidation, and indicates that adipic acid may be converted into succinic acid.