Blood flow restriction (BFR) remarkably enhances intramuscular energetic metabolism in resistance exercise; however, its mechanism has not been known. We hypothesized that it was associated with oxidative capacity. Therefore, we investigated intramuscular metabolic responses during low-intensity resistance exercise with BFR in track athletes. Twelve male college athletes were recruited and performed unilateral plantar-flexion (30 repetitions/minute for 2 minutes) during low-intensity exercise at 20% of one repetition maximum with BFR. Intramuscular energetic metabolism and muscle oxygenation were evaluated using 31P-magnetic resonance spectroscopy and near infrared spectroscopy, respectively. Subjects were divided into the two groups based on aerobic capacity. Phosphocreatine (PCr) decrease in subjects with high-aerobic capacity during BFR exercise was greater than that in subjects with low-aerobic capacity (p=0.077), without the difference in muscular oxygenation. The PCr decrease during BFR exercise was significantly correlated with peak oxygen uptake (r=0.735, p<0.01). In conclusion, the effects of low-intensity resistance exercise with BFR might be greater in subjects with higher aerobic capacity.
The purpose of this study was to investigate how 6 weeks of handgrip endurance exercise training affects maximal muscle O2 consumption (muscle V·O2) during incremental handgrip exercise and muscle energetics during high intensity exercise. Eight healthy female subjects performed dynamic handgrip exercise training until exhaustion at 30% of maximum voluntary contraction at 1 set per day for 6 weeks. The measurement site was the right finger flexor muscles. Muscle V·O2 was evaluated using near-infrared continuous wave spectroscopy during incremental handgrip exercise pre- and post-training. Both phosphocreatine (PCr) and muscle pH during exercise were evaluated using 31-phosphorus magnetic resonance spectroscopy. After the training, performance time was significantly longer than pre-training (52.9±3.5 and 84.5±5.8 s, pre- and post-training respectively) (p<0.05). No significant difference of maximal muscle V·O2 was found between pre- and post-training (18.3±1.9 and 18.1±1.2 fold of resting). Maximal exercise workload was significantly greater post-training than pre-training. PCr and muscle pH levels at exhaustion were unchanged between pre- and post-training. These findings have significant implications for the development of exercise tolerance under severe metabolic acidosis.
Background: Bidirectional approach using popliteal method has been reported to improve the initial success rate of endovascular treatment (EVT) of superficial femoral arterial chronic total occlusion (SFA CTO). However, popliteal arterial injury is concerned by sheath insertion. To minimize the vascular injury, we have used plastic cannula by echoguidance alternative to sheath for popliteal cannulation. The purpose of this study was to investigate the safety and feasibility of retrograde popliteal approach using plastic cannula in EVT of SFA CTO. Methods: We used plastic cannula system consisting of Teflon cannula with the outer diameter of 1.3mm and the length of 150 mm, and 20 G needle. Through the plastic cannula inserted into the popliteal artery, the guidewire within the microcatheter was retrogradely crossed through SFA CTO and was pulled through 6Fr femoral sheath. Ballooning and stenting were performed from the femoral sheath. We retrospectively investigated the safety and feasibility of this technique according to the initial success, popliteal arterial injury. Results: The initial success was obtained in 21 of the 23 SFA CTO treated with this technique although the averaged CTO length was 18.1 cm. No major popliteal injury or hematoma was observed by sonography. Conclusion: Retrograde popliteal approach using plastic cannula was feasible and a less invasive technique for EVT of SFA CTO.
We report four chronic juxtarenal aortic occluded cases that underwent aorto-bifemoral bypass grafting. All were male, and their mean age was 61 years old (41–76). We performed a simple suprarenal clamping method for all cases. A case of a patient with a middle grade high creatinine value (2.27 mg/dl) needed temporary dialysis postoperatively for a few months. Suprarenal aortic simple clamping method is recognized as a safe procedure for the patients with normal preoperative renal function; however, we insist that some renal protection should be considered for middle grade renal dysfunction.
Twenty-one patients (with 24 limbs) with venous stasis ulcers were treated with endovenous laser ablation (EVLA) from March 2008 to March 2011. Six months after EVLA, 96% of the ulcers healed without complication. Because of its less invasiveness, all patients except one with a giant ulcer could be treated in an outpatient clinic. Two cases (with 4 limbs) had recurrence of stasis ulcers and 2 limbs were treated with foam sclerotherapy. The initial experience in our department suggests that EVLA is useful for treating patients with stasis ulcer due to varicose veins.
Saddle embolism causes acute severe ischemia to bilateral lower limbs and myonephropathic metabolic syndrome (MNMS) frequently after reperfusion. The prognosis of this disease is not so good. Therefore, we should make a diagnosis and an adequate treatment for this disease as soon as possible. We have encountered and reported two cases of saddle embolism which took a different post operative course with review of literature.
The main error factors on near-infrared spectroscopy (NIRS) measurements for deep tissue are (1) thickness of overlying tissues, (2) oxygenation of surface tissues, (3) difference between an assumed value and an actual value of scattering coefficient for tissues, and (4) concentrations of hemoglobin derivatives. These factors affect the accuracy on time-resolved NIRS, intensity-modulated NIRS, spatially resolved NIRS, and continuous wave NIRS. In this paper, we present the accurate oxygenation measurement in surface and deep tissues using continuous wave and spatially resolved NIRS. The relationship between spatial distribution of light intensity and absorption coefficient of the muscle was obtained from the Monte Carlo simulation. Fat thickness greatly affected the absolute value of hemoglobin concentration. The influence of skin oxygenation caused several percent error factor of muscle oxygenation. We obtained curves to correct the influences. To reduce the error due to assumed scattering coefficient, a simple method for determining optical properties with laser rangefinder was practical and useful. Moreover, the absolute values of hemoglobin derivative concentrations were successfully measured by spatially resolved NIRS. It was also helpful for accurate oxygenation measurement. The combination of these measurements and corrections would be essential for an accurate NIRS.