The dependence of preferred competitive racing distance on muscle fibre type composition and ACTN3 genotype in speed skaters

It is generally accepted that muscle fibre composition may influence physical performance. The α-actinin-3 (ACTN3) gene R577X polymorphism is suspected to be one of the contributing gene variations in the determination of muscle fibre type composition and athletic status. In the present study, we examined the dependence of average preferred racing distance (PRD) on muscle fibre type composition of the vastus lateralis muscle in 34 subelite Russian speed skaters (20 men and 14 women) who competed in races of different length (500-10,000 m). We also investigated the association between theACTN3polymorphism and muscle fibre characteristics in 94 subjects (60 physically active healthy men and 34 speed skaters), as well as the relationship between PRD andACTN3genotype in 115 subelite and elite speed skaters. In addition,ACTN3genotype and allele frequencies of the 115 speed skaters were compared with 1301 control subjects. TheACTN3XX genotype frequency was significantly lower in sprinters (n= 39) compared with control subjects (2.6versus14.5%;P= 0.034). We observed a positive relationship between PRD and the proportion of slow-twitch muscle fibres that was close to linear, but better fitted a logarithmic curve (r= 0.593,P< 0.0005). TheACTN3R577X polymorphism was associated with muscle fibre composition (slow-twitch fibres: RR genotype, 51.7 (12.8)%; RX, 57.4 (13.2)%; XX 61.5 (16.3)%; ρ= 0.215;P= 0.049) in the overall muscle biopsy group, and with PRD of all athletes (ρ= 0.24,P= 0.010), indicating thatACTN3XX genotype carriers exhibit a higher proportion of slow-twitch fibres and prefer to skate long-distance races. However, the majority of the association between muscle fibre type and PRD was independent ofACTN3genotype. In conclusion, theACTN3R577X polymorphism is associated with preferred racing distance in speed skaters and muscle fibre type composition. Thus, it is probably partly via associations with fibre type that the R577X polymorphism contributes to a small but perhaps important component of the ability to perform at a high level in speed skating

Targeted Therapy of Myelofibrosis

Background. Myelofibrosis (primary myelofibrosis, post-essential trombocythemia myelofibrosis, post-polycythemia myelofibrosis) is the most complex and pressing problem among all Ph-negative myeloproliferative diseases. The present article summarizes the author’s experience of using new Janus kinase inhibitors in routine clinical practice, and compares the data with the results of other clinical research. Aim. To evaluate the use of ruxolitinib in patients with myelofibrosis. Materials & Methods. Our analysis includes 48 patients (21 men and 27 women) with histologically verified myelofibrosis (primary myelofibrosis in 36 cases, post-essential trombocythemia myelofibrosis in 10 cases, and post-polycythemia myelofibrosis in 2 cases) in a chronic stage. All patients received ruxolitinib. Median age at the start of therapy was 60 years (range from 35 to 79). Massive splenomegaly (≥ 10 cm below the costal margin) was found in 34 (71 %) of 48 patients. The initial dose of ruxolitinib was determined by the platelet level. The efficacy of the therapy was evaluated in accordance with ELN 2013 criteria. Results. Median duration of treatment was 18 months (range from 1 to 50 months). Symptoms of intoxication were relieved in 33 of 37 patients (89 %). The spleen size decreased in 64 % of patients. In 33 % of cases spleen size did not change, whereas an increase was observed in 3 % of patients. In the majority of patients hemoglobin level remained stable through the course of treatment. Three of 14 transfusion dependent patients did not require blood transfusions after 3 months of therapy. In patients with high thrombocyte levels prior to ruxolitinib therapy the mean level was approaching normal by the end of the 1st month of treatment. The median JAK2V617F mutant allele burden at the beginning treatment was 56.5 % (n = 20; 22.5–126.1 %). After 6 moths of treatment it accounted for 62.3 % (n = 11; 25.4–79.7 %) and in 12 months accounted for 47.4 % (n = 12; 14.2–102.2 %). By the time of the analysis 42 of 48 patients continued the ruxolitinib treatment (88 %). Death occurred in 4 patients. Overall 1-year (92 %) and 2-year (87 %) survival corresponds to the data of COMFORT-I, COMFORT-II and JUMP clinical trials. Conclusion. Ruxolitinib showed to be an effective treatment for myelofibrosis. The most pronounced and rapid effect ruxolitinib had on the spleen size and the symptoms of intoxication. The tolerability of ruxolitinib was satisfactory in the majority of patients. According to the author’s data, ruxolitinib had a small impact on the JAK2V617F mutant allele burden. The overall survival rate in patients with myelofibrosis, receiving ruxolitinib in the clinical setting was similar to that of in the clinical trials

The combined impact of metabolic gene polymorphisms on elite endurance athlete status and related phenotypes

Endurance performance is a complex phenotype subject to the influence of both environmental and genetic factors. Although the last decade has seen a variety of specific genetic factors proposed, many in metabolic pathways, each is likely to make a limited contribution to an 'elite' phenotype: it seems more likely that such status depends on the simultaneous presence of multiple such variants. The aim of the study was to investigate individually and in combination the association of common metabolic gene polymorphisms with endurance athlete status, the proportion of slow-twitch muscle fibers and maximal oxygen consumption. A total of 1,423 Russian athletes and 1,132 controls were genotyped for 15 gene polymorphisms, of which most were previously reported to be associated with athlete status or related intermediate phenotypes. Muscle fiber composition of m. vastus lateralis in 45 healthy men was determined by immunohistochemistry. Maximal oxygen consumption of 50 male rowers of national competitive standard was determined during an incremental test to exhaustion on a rowing ergometer. Ten 'endurance alleles' (NFATC4 Gly160, PPARA rs4253778 G, PPARD rs2016520 C, PPARGC1A Gly482, PPARGC1B 203Pro, PPP3R1 promoter 5I, TFAM 12Thr, UCP2 55Val, UCP3 rs1800849 T and VEGFA rs2010963 C) were first identified showing discrete associations with elite endurance athlete status. Next, to assess the combined impact of all 10 gene polymorphisms, all athletes were classified according to the number of 'endurance' alleles they possessed. The proportion of subjects with a high (≥9) number of 'endurance' alleles was greater in the best endurance athletes compared with controls (85.7 vs. 37.8%, P = 7.6 × 10-6). The number of 'endurance' alleles was shown to be positively correlated (r = 0.50; P = 4.0 × 10-4) with the proportion of fatigue-resistant slow-twitch fibers, and with maximal oxygen consumption (r = 0.46; P = 7.0 × 10-4). These data suggest that the likelihood of becoming an elite endurance athlete depends on the carriage of a high number of endurance-related alleles

PPARα gene variation and physical performance in Russian athletes

Peroxisome proliferator-activated receptor α (PPARα) regulates genes responsible for skeletal and heart muscle fatty acid oxidation. Previous studies have shown that the PPARα intron 7 G/C polymorphism was associated with left ventricular growth in response to exercise. We speculated that GG homozygotes should be more prevalent within a group of endurance-oriented athletes, have normal fatty acid metabolism, and increased percentages of slow-twitch fibers. We have tested this hypothesis in the study of a mixed cohort of 786 Russian athletes in 13 different sporting disciplines prospectively stratified by performance (endurance-oriented athletes, power-oriented athletes and athletes with mixed endurance/power activity). PPARα intron 7 genotype and allele frequencies were compared to 1,242 controls. We found an increasing linear trend of C allele with increasing anaerobic component of physical performance (P=0.029). GG genotype frequencies in endurance-oriented and power-oriented athletes were 80.3 and 50.6%, respectively, and were significantly (P<0.0001) different compared to controls (70.0%). To examine the association between PPARα gene variant and fiber type composition, muscle biopsies from m. vastus lateralis were obtained and analyzed in 40 young men. GG homozygotes (n=25) had significantly (P=0.003) higher percentages of slow-twitch fibers (55.5±2.0 vs 38.5±2.3%) than CC homozygotes (n=4). In conclusion, PPARα intron 7 G/C polymorphism was associated with physical performance in Russian athletes, and this may be explained, in part, by the association between PPARα genotype and muscle fiber type composition. © Springer-Verlag 2006

A protein functionalization platform based on selective reactions at methionine residues.

Nature has a remarkable ability to carry out site-selective post-translational modification of proteins, therefore enabling a marked increase in their functional diversity1. Inspired by this, chemical tools have been developed for the synthetic manipulation of protein structure and function, and have become essential to the continued advancement of chemical biology, molecular biology and medicine. However, the number of chemical transformations that are suitable for effective protein functionalization is limited, because the stringent demands inherent to biological systems preclude the applicability of many potential processes2. These chemical transformations often need to be selective at a single site on a protein, proceed with very fast reaction rates, operate under biologically ambient conditions and should provide homogeneous products with near-perfect conversion2-7. Although many bioconjugation methods exist at cysteine, lysine and tyrosine, a method targeting a less-explored amino acid would considerably expand the protein functionalization toolbox. Here we report the development of a multifaceted approach to protein functionalization based on chemoselective labelling at methionine residues. By exploiting the electrophilic reactivity of a bespoke hypervalent iodine reagent, the S-Me group in the side chain of methionine can be targeted. The bioconjugation reaction is fast, selective, operates at low-micromolar concentrations and is complementary to existing bioconjugation strategies. Moreover, it produces a protein conjugate that is itself a high-energy intermediate with reactive properties and can serve as a platform for the development of secondary, visible-light-mediated bioorthogonal protein functionalization processes. The merger of these approaches provides a versatile platform for the development of distinct transformations that deliver information-rich protein conjugates directly from the native biomacromolecules

Genome-wide association study identifies three novel genetic markers associated with elite endurance performance

To investigate the association between multiple single-nucleotide polymorphisms (SNPs), aerobic performance and elite endurance athlete status in Russians. By using GWAS approach, we examined the association between 1,140,419 SNPs and relative maximal oxygen consumption rate (VO2max) in 80 international-level Russian endurance athletes (46 males and 34 females). To validate obtained results, we further performed case-control studies by comparing the frequencies of the most significant SNPs (with P<10-5-10-8) between 218 endurance athletes and opposite cohorts (192 Russian controls, 1367 European controls, and 230 Russian power athletes). Initially, six 'endurance alleles' were identified showing discrete associations with •VO2maxboth in males and females. Next, case-control studies resulted in remaining three SNPs (NFIA-AS2 rs1572312, TSHR rs7144481, RBFOX1 rs7191721) associated with endurance athlete status. The C allele of the most significant SNP, rs1572312, was associated with high values of •VO2max(males: P=0.0051; females: P=0.0005). Furthermore, the frequency of the rs1572312 C allele was significantly higher in elite endurance athletes (95.5%) in comparison with non-elite endurance athletes (89.8%, P=0.0257), Russian (88.8%, P=0.007) and European (90.6%, P=0.0197) controls and power athletes (86.2%, P=0.0005). The rs1572312 SNP is located on the nuclear factor I A antisense RNA 2 (NFIA-AS2) gene which is supposed to regulate the expression of the NFIA gene (encodes transcription factor involved in activation of erythropoiesis and repression of the granulopoiesis). Our data show that the NFIA-AS2 rs1572312, TSHR rs7144481 and RBFOX1 rs7191721 polymorphisms are associated with aerobic performance and elite endurance athlete status

Ibrutinib in the Treatment of Refractory Chronic Lymphocytic Leukemia

Background & Aims. This paper presents the results of the observational study of ibrutinib in patients with chronic lymphocytic leukemia (CLL), conducted in SP Botkin Municipal Clinical Hospital. The main objective was the analysis of complications of ibrutinib and identification of factors, influencing the dosage regimen; the secondary objective was the estimation of the total response to treatment, event-free and overall survival. Materials & Methods. The study included 96 patients with CLL with indications for ibrutinib therapy. The median age was 64,9 years (range 32–91 years), the study population consisted of 69 (72 %) men and 27 (28 %) women. The condition of 25 (26 %) patients according to the ECOG scale was of > 3 points. The disease of stage C were diagnosed in 36 (37 %) patients . Deletion of 17p/TP53 mutations were detected in 29 (33 %) of 87 patients. Seventy patients had refractory CLL. The median of the number of the lines of the previous therapy was 3 (range 1–9). Adverse events were assessed in accordance with the CTCAE criteria, version 4.0; the bleeding severity was evaluated using ITP-specific bleeding score; hematological complications were classified according to the recommendations of IWCLL-2008. Results. Ibrutinib was administered at a dosage of 420 mg per day daily until progression or intolerable toxicity. The median duration of ibrutinib therapy was 10.3 months. Ibrutinib was shown to have moderate toxicity, mostly of grade I or II. The bleeding was the most frequent complication. Of the hematological complications, thrombocytopenia was the most common (35 %); neutropenia grade III) developed in 26 % of patients. The treatment response was assessed in 92 patients. The overall response to treatment was 89 %. Complete remission, partial remission and partial remission with lymphocytosis were achieved in 4 (4 %), 57 (62 %), and 21 (23 %) patients, respectively. The event-free survival and overall survival by the month 10 was 90 % and 91 %, respectively. For this observation period, ECOG status and the number of the lines of therapy prior to ibrutinib had the prognostic value. Conclusion. Ibrutinib was shown to have high efficiency in relapsed/refractory forms of CLL. The nature of the ibrutinib toxicity is fundamentally different from that of the conventional chemotherapy. The frequency of ibrutinib therapy complications and patients’ non-compliance depends on the intensity of the previous treatment of CLL. Despite a short observation period, it can be concluded that ibrutinib had the greatest impact on the patient’s quality of life when administered for the first relapse. The low toxicity of ibrutinib is likely to allow the combination with other antitumor agents