Characteristics of myogenic response and ankle torque recovery after lengthening contraction-induced rat gastrocnemius injury

BACKGROUND: Although muscle dysfunction caused by unfamiliar lengthening contraction is one of most important issues in sports medicine, there is little known about the molecular events on regeneration process. The purpose of this study was to investigate the temporal and spatial expression patterns of myogenin, myoD, pax7, and myostatin after acute lengthening contraction (LC)-induced injury in the rat hindlimb. METHODS: We employed our originally developed device with LC in rat gastrocnemius muscle (n = 24). Male Wistar rats were anesthetized with isoflurane (aspiration rate, 450 ml/min, concentration, 2.0%). The triceps surae muscle of the right hindlimb was then electrically stimulated with forced isokinetic dorsi-flexion (180°/sec and from 0 to 45°). Tissue contents of myoD, myogenin, pax7, myostatin were measured by western blotting and localizations of myoD and pax7 was measured by immunohistochemistry. After measuring isometric tetanic torque, a single bout of LC was performed in vivo. RESULTS: The torque was significantly decreased on days 2 and 5 as compared to the pre-treatment value, and recovered by day 7. The content of myoD and pax7 showed significant increases on day 2. Myogenin showed an increase from day 2 to 5. Myostatin on days 5 and 7 were significantly increased. Immunohistochemical analysis showed that myoD-positive/pax7-positive cells increased on day 2, suggesting that activated satellite cells play a role in the destruction and the early recovery phases. CONCLUSION: We, thus, conclude that myogenic events associate with torque recovery after LC-induced injury

Anterior Limbus Vertebra and Intervertebral Disk Degeneration in Japanese Collegiate Gymnasts

Background: Magnetic resonance imaging (MRI) studies have shown that gymnasts have a high prevalence of radiologicalabnormalities, such as intervertebral disk degeneration (IDD) and anterior limbus vertebra (ALV). These 2 abnormalities may coexistat the same spinal level. However, the relationship between IDD and ALV remains unclear.Hypothesis: A significant relationship exists between IDD and ALV in Japanese collegiate gymnasts.Study Design: Case-control study.Methods: A total of 104 Japanese collegiate gymnasts (70 men and 34 women; age, 19.7 + 1.0 years) with 11.8 + 3.6 years ofsporting experience participated. T1- and T2-weighted MRIs were used to evaluate ALV and IDD.Results: The prevalence among the gymnasts of IDD and ALV was 40.4% (42/104) and 20.2% (21/104), respectively. Theprevalence of IDD was significantly higher in gymnasts with ALV than those without ALV, as determined using the chi-square test.Logistic regression analysis demonstrated a significant association between IDD and ALV (adjusted odds ratio [OR], 6.60; 95%confidence interval [CI], 2.14-20.35). IDD was further grouped by whether it was present in the upper lumbar region (L1-2, L2-3,and L3-4 disks) or in the lower lumbar region (L4-5 and L5-S1 disks). Upper IDD had a greater association with ALV (adjustedOR, 33.17; 95% CI, 7.09-155.25) than did lower IDD (adjusted OR, 6.71; 95% CI, 1.57-28.73).Conclusion: In Japanese collegiate gymnasts, ALV is a predictor of IDD, especially in the upper lumbar region.Clinical Relevance: Information regarding ALV is important to prevent IDD in Japanese collegiate gymnasts.Keywords: endplate lesion; gymnastics; intervertebral disk degeneration; magnetic resonance imagin

A case of acute myocardial infarction during perioperative period of non-cardiac surgery in a patient with antiphospholipid syndrome and a history of coronary artery bypass surgery

AbstractA 65-year-old woman underwent coronary artery bypass surgery and was diagnosed with antiphospholipid syndrome (APS) at the same time in 1985. She was admitted to our hospital to undergo mastectomy for left breast cancer in 2012. She was put on intravenous infusion of heparin and stopped receiving both antiplatelet agents and warfarin. The operation was performed without complications, and antithrombotic therapy was restarted one day after the operation. On day 6 postoperative, she complained of sudden chest pain and on examination she was diagnosed with acute myocardial infarction. The culprit lesion was in a saphenous vein graft and coronary intervention was performed.<Learning objective: Antithrombotic therapy for patients with APS is complicated because of prolonged baseline activated partial thromboplastin time (aPTT). An effective perioperative antithrombotic therapy for APS patients who have a history of coronary artery disease and have undergone non-cardiac surgery has not yet been established. A safe strategy for such a therapy should therefore be discussed.

Follicular thyroglobulin (TG) suppression of thyroid-restricted genes involves the apical membrane asialoglycoprotein receptor and TG phosphorylation.

Follicular thyroglobulin (TG) decreases expression of the thyroid-restricted transcription factors, thyroid transcription factor (TTF)-1, TTF-2, and Pax-8, thereby suppressing expression of the sodium iodide symporter, thyroid peroxidase, TG, and thyrotropin receptor genes (Suzuki, K., Lavaroni, S., Mori, A., Ohta, M., Saito, J., Pietrarelli, M., Singer, D. S., Kimura, S., Katoh, R., Kawaoi, A. , and Kohn, L. D. (1997) Proc. Natl. Acad. Sci. U. S. A. 95, 8251-8256). The ability of highly purified 27, 19, or 12 S follicular TG to suppress thyroid-restricted gene expression correlates with their ability to bind to FRTL-5 thyrocytes and is inhibited by a specific antibody to the thyroid apical membrane asialoglycoprotein receptor (ASGPR), which is related to the ASGPR of liver cells. Phosphorylating serine/threonine residues of TG, by autophosphorylation or protein kinase A, eliminates TG suppression and enhances transcript levels of the thyroid-restricted genes 2-fold in the absence of a change in TG binding to the ASGPR. Follicular TG suppression of thyroid-restricted genes is thus mediated by the ASPGR on the thyrocyte apical membrane and regulated by a signal system wherein phosphorylation of serine/threonine residues on the bound ligand is an important component. These data provide a hitherto unsuspected role for the ASGPR in transcriptional signaling, aside from its role in endocytosis. They establish a functional role for phosphorylated serine/threonine residues on the TG molecule

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: its history and development, and regional medical cooperation in Fukushima

Chronic thromboembolic pulmonary hypertension (CTEPH) is designated as an intractable disease by the Ministry of Health, Labour and Welfare of Japan, and has an extremely poor prognosis if untreated. Surgical pulmonary endarterectomy is the curative treatment for cases in which the organized thrombi are located in the central part of the pulmonary artery, but there had been no effective treatment for cases in which the thrombi are located in the peripheral part of the pulmonary artery. Recently, balloon pulmonary angioplasty (BPA), a transcatheter procedure to dilate stenotic or occluded lesions in the peripheral pulmonary artery, has been rapidly developed. Although BPA was once a globally abandoned procedure due to hemorrhagic complications, Japanese experts have improved the technique, and its safety and efficacy have been enhanced. As a result, BPA is now being reevaluated worldwide. This review describes the history and development of BPA in the treatment of CTEPH, as well as the status of this treatment in Fukushima Prefecture

The Effect of Changing the Contraction Mode During Resistance Training on mTORC1 Signaling and Muscle Protein Synthesis

Acute resistance exercise (RE) increases muscle protein synthesis (MPS) via activation of mechanistic target of rapamycin complex (mTORC), and chronic resistance exercise training (RT) results in skeletal muscle hypertrophy. Although MPS in response to RE is blunted over time during RT, no effective restorative strategy has been identified. Since eccentric muscle contraction (EC) has the potential to strongly stimulate mTORC1 activation and MPS, changing the muscle contraction mode to EC might maintain the MPS response to RE during chronic RT. Male rats were randomly divided into RE (1 bout of RE) and RT (13 bouts of RE) groups. Additionally, each group was subdivided into isometric contraction (IC) and EC subgroups. The RE groups performed acute, unilateral RE using IC or EC. The RT groups performed 12 bouts of unilateral RE using IC. For bout 13, the RT-IC subgroup performed a further IC bout, while the RT-EC subgroup changed to EC. All muscle contractions were induced by percutaneous electrical stimulation. Muscle samples were obtained at 6 h post exercise in all groups. After the 1st RE bout, the EC group showed significantly higher p70S6K Thr389 phosphorylation than the IC group. However, the phosphorylation of other mTORC1-associated proteins (4E-BP1 and ribosomal protein S6) and the MPS response did not differ between the contraction modes. After the 13th bout of RE, mTORC1 activation and the MPS response were significantly blunted as compared with the 1st bout of RE. Changing from IC to EC did not improve these responses. In conclusion, changing the contraction mode to EC does not reinvigorate the blunted mTORC1 activation and MPS in response to RE during chronic RT

Genetic profile of sports climbing athletes from three different ethnicities

This study aimed to investigate the ACTN3 R577X, ACE I/D, CKM rs8111989, and TRHR rs7832552 genotypes in climbers and controls in three ethnicities. The study consisted of 258 climbers (Japanese, n = 100; Polish, n = 128; Russian, n = 30) and 1151 controls (Japanese: n = 332, Polish: n = 635, Russian: n = 184). Genotyping results were analyzed using the TaqMan approach in Japanese and Polish subjects and HumanOmni1-Quad Bead Chips in Russian subjects. There were no significant differences in ACTN3 R577X and ACE I/D polymorphism distribution between climbers and controls in any ethnic cohort or model. The frequencies of the C allele in the CKM polymorphism and the T allele in the TRHR polymorphism were higher in climbers than in controls only in the Russian cohort (p = 0.045 and p = 0.039, respectively). The results of the meta-analysis on three cohorts showed that the frequency of XX + RX genotypes in the ACTN3 R577X polymorphism was significantly higher in climbers than that in the controls (p = 0.01). The X allele of the ACTN3 R577X polymorphism was associated with sport climbing status, as assessed using a meta-analysis of climbers across three different ethnicities

Is COL1A1 Gene rs1107946 Polymorphism Associated with Sport Climbing Status and Flexibility?

The purpose of this study was to compare the frequency of COL1A1 rs1107946 polymorphism between sport climbers and controls from three ethnic groups (Japanese, Polish, and Russian) and investigate the effect of the COL1A1 rs1107946 polymorphism on the age-related decrease in flexibility in the general population. Study I consisted of 1929 healthy people (controls) and 218 climbers, including Japanese, Polish, and Russian participants. The results of the meta-analysis showed that the frequency of the AC genotype was higher in climbers than in the controls (p = 0.03). Study II involved 1093 healthy Japanese individuals (435 men and 658 women). Flexibility was assessed using a sit-and-reach test. There was a tendency towards association between sit-and-reach and the COL1A1 rs1107946 polymorphism (genotype: p = 0.034; dominant: p = 0.435; recessive: p = 0.035; over-dominant: p = 0.026). In addition, there was a higher negative correlation between sit-and-reach and age in the AA + CC genotype than in the AC genotype (AA + CC: r = -0.216, p &lt; 0.001; AC: r = -0.089, p = 0.04; interaction p = 0.037). However, none of these results survived correction for multiple testing. Further studies are warranted to investigate the association between the COL1A1 gene variation and exercise-related phenotypes

Low-load bench press and push-up induce similar muscle hypertrophy and strength gain

Aim: To investigate the effect of push-up training with a similar load of to 40% of 1- repetition maximumal (1RM) bench press on muscle hypertrophy and strength gain in men. Methods: Eighteen male participants (age, 20.2 ± 0.73 years, range: 19−22 years, height: 169.8 ± 4.4 cm, weight: 64.5 ± 4.7 kg) were randomly assigned to one of two experimental groups: bench press at 40%1RM (bench-press group, n = 9) or push-ups with position adjusted (e.g. kneeling) to the same load of bench-press 40%1RM (push-up group, n = 9), performed twice per week for 8 weeks. Muscle thickness at three sites (biceps, triceps, and pectoralis major), bench-press 1RM, maximum repetition at 40%1RM, and power output (medicine ball throw) were measured before and after the training period. Results: Significant increases in 1RM and muscle thickness (triceps and pectoralis major) were observed in bench-press group (1RM, from 60.0 ± 12.1 kg to 65.0 ± 12.1 kg, p < 0.01; triceps, from 26.3 ± 3.7 mm to 27.8 ± 3.8 mm, p < 0.01; pectoralis major, from 17.0 ± 2.8 mm to 20.8 ± 4.8 mm, p < 0.01) and in the push-up group (1RM, from 61.1 ± 12.2 kg to 64.2 ± 12.5 kg, p < 0.01; triceps, 27.7 ± 5.7 mm to 30.4 ± 6.6 mm, p < 0.01; pectoralis major, from 17.0 ± 2.8 mm to 20.8 ± 4.8 mm, p < 0.01). Biceps thickness significantly increased only in the bench-press group (28.4 ± 3.3 mm to 31.5 ± 3.7 mm, p < 0.01). Neither power output performance nor muscle endurance capacity changed in either group. Conclusions: Push-up exercise with similar load to 40%1RM bench press is comparably effective for muscle hypertrophy and strength gain over an 8-week training period