Study of muscle contraction induced by electrical pulse stimulation and nitric oxide in C2C12 myotube cells.

PURPOSE: This study aimed to examine the independent effect of electrical pulse stimulation(EPS) and nitric oxide(NO) on muscle contraction and their synergistic or combined effect on contraction phenomenon using C2C12 mouse skeletal muscle cells. METHODS: Some differentiated C2C12 myotube cells were untreated (control). Other cells did not receive EPS and did receive 0.5, 1.0, or 2.0 mM of the NO donor, S-nitroso-N-acetyl-penicillamine (SNAP; -E/S0.5, -E/S1.0, and -E/S2.0, respectively). For the EPS treatments (0.3 V/mm, 1.0 Hz, and 4.0 ms), differentiated C2C12 myotube cells received only EPS or both EPS and the SNAPtreatments at the same concentrations (+E/-S, +E/S0.5, +E/S1.0, and +E/S2.0, respectively). All samples were then cultured for 4 days. RESULTS: Differentiated C2C12 cellswere stimulated by the EPS, NO, and EPS+NO treatments. The cell length of the +E/S2.0 Group after the 4-day culture (84.2±13.2㎛) was the shortest of all the groups. The expressions of AMPK, JNK, Akt, eNOS, GLUT4, and PGC1α proteins were noticeably dominant. The results indicated synergistic effect on muscle contraction of simultaneously applied EPS and SNAP. CONCLUSION: Motor skills were significantly improved when exercise was accompanied by the intake of NO precursor and/or NO, compared to that upon their independent application or treatment.

The effect of swimming exercise and powdered-Salicornia herbacea L. ingestion on glucose metabolism in STZ-induced diabetic rats.

PURPOSE: The purpose of this study is to observe the effects of Salicornia herbacea L. powder ingestion on carbohydrate metabolism in STZ-induced diabetic rats. METHODS: To achieve this objective, 35 Sprague-Dawley male rats were raised with feed mixed with Salicornia herbacia L. powder and given specific periods to swim for 5 weeks. There was no significant difference in the insulin increase rate while ingesting Salicornia herbacea L. powder and simultaneously exercising. RESULTS: Compared to the diabetes mellitus group, HOMA-IR was significantly decreased in the diabetes mellitus + exercise group, diabetes mellitus + Salicornia herbacea group, and the diabetes mellitus + Salicornia herbacea + exercise group. However, changes in blood glucose were significant in each group. Thus, for the result of GLUT-4 and GLUT-2, which are the glycose transporters of the liver and muscle, diabetes mellitus + exercise group, diabetes mellitus + Salicornia herbacea group, and diabetes mellitus + Salicornia herbacea + exercise group showed significantly higher expressions. The glycogen concentration of the liver and muscle was significantly increased in the diabetes mellitus + exercise group, diabetes mellitus + Salicornia herbacea group, and diabetes mellitus + Salicornia herbacea + exercise group. CONCLUSION: With the results above, it seems that taking Salicornia herbacea L. powder and exercise will help prevent various diabetic complications. Therefore, the findings of this study could justify Salicornia herbacea L. powder with its basal data of physiological activities and pharmacological components as a type of health functional food.

Trophic transfer and biotransformation of polychlorinated biphenyls in zebra mussel, round goby, and smallmouth bass in Lake Erie, USA.

Trophic transfer of polychlorinated biphenyl (PCB) congeners in zebra mussels (Dreissena polymorpha), round gobies (Neogobius melanstomus), and smallmouth bass (Micropterus dolomieu) were assessed in four sites along the south shore of the west and central basin of Lake Erie (all sites were in OH, USA). Total PCB levels in smallmouth bass (1,091-1,520 ng/g wet weight) and round gobies (118-256 ng/g wet weight) were similar among sites despite a west-to-east decrease in total PCB concentrations in zebra mussels (29-97 ng/g wet weight). At all sites, PCB body burden increased three- to fivefold at each successive trophic level, suggesting biomagnification in this nonnative food chain. Whereas fish species were dominated by the hexachlorine homologue, zebra mussels were dominated by penta- and hexachlorine homologues; the average degree of chlorination of PCBs was 56.1% for zebra mussels, 60.4% for round goby, and 59.9% for smallmouth bass bodies. Predictive structure-activity relationships based on chemical characteristics, such as the octanol-water partition coefficient (log K(ow)), had little predictive power on bioaccumulation and biotransformation of PCB congeners because of nonlinearity, threshold relationships, and species-specific differences. Calculated trophic transfer for the smallmouth bass-round goby linkage was higher than for the round goby-zebra mussel linkage. Only when PCB congeners were grouped by chemical structure first (vicinal [adjacent] H-atom position in the phenyl ring) were linear relationships achieved. It appeared that the chemical group to which each congener belonged influenced biotransformation more than species-specific (round gobies vs smallmouth bass) differences. Biotic changes at midtrophic levels, such as exotic species invasions, may have an increasingly important role in determining pollutant cycling and hence pollutant residues in top predators.

Use of a neck brace minimizes double-lumen tube displacement during patient positioning.

PURPOSE: When patients are moved from the supine to the lateral decubitus position, the double-lumen endobronchial tube (DLT) is often displaced. The aim of this study was to determine whether a DLT is displaced when there are no movements of the head and neck. METHODS: One hundred patients scheduled for elective thoracic surgery were randomly divided into control and brace groups. Only a left-sided DLT was used during the study. All patients in the brace group wore a neck collar before the positional change. Using a fibreoptic bronchoscope, the distance from the tracheal opening to the main carina and from the bronchial opening to the bronchial carina was measured in the supine and lateral decubitus positions. RESULTS: Displacement of the DLT (mean +/- SD) during a change from the supine to the lateral decubitus position was greater in the control group (6.3 +/- 5.5 mm in the trachea; 2.4 +/- 3.6 mm in the bronchus) than in the brace group (2.2 +/- 3.9 mm in the trachea; 0.6 +/- 3.1 mm in the bronchus); (P < 0.001). The incidence of clinically significant displacement, greater than 5 mm from the initial correct position, was higher in the control group than in the brace group (48% vs 12%, P < 0.001). CONCLUSION: By restricting head and neck movements with a neck brace, the DLT displacement could be minimized while positioning patients for thoracotomy. The main cause of the DLT displacement during lateral positioning appears to be related to movement of the head and neck.

(-)-Hydroxycitric acid ingestion increases fat utilization during exercise in untrained women.

(-)-Hydroxycitric acid (HCA) is a competitive inhibitor of the enzyme ATPcitrate-lyase, which inhibits lipogenesis in the body. Moreover, HCA increases endurance exercise performance in trained mice and athletes. However, had not been investigated in untrained animals and humans. Therefore, we investigated the effects of short-term HCA ingestion on endurance exercise performance and fat metabolism in untrained women. In two experiments designed as a double-blind crossover test, six subjects ingested 250 mg of HCA or placebo (same amount of dextrin) via capsule for 5 d and then participated in cycle ergometer exercise. They cycled at 40% VO2max for 1 h and then the exercise intensity was increased to 60% VO2max until exhaustion on day 5 of each experiment. HCA tended to decrease the respiratory exchange ratio (RER) and carbohydrate oxidation during 1 h of exercise. In addition, exercise time to exhaustion was significantly enhanced (p<0.05). These results suggest that HCA increases fat metabolism, which may be associated with a decrease in glycogen utilization during the same intensity exercise and enhanced exercise performance.

Short-term (-)-hydroxycitrate ingestion increases fat oxidation during exercise in athletes.

(-)-Hydroxycitrate (HCA) is known to inhibit increasing malonyl CoA concentration during endurance exercise. Furthermore, a short-term administration of HCA enhances endurance exercise performance in mice. Therefore we investigated the short-term administration of HCA on the exercise performance of athletes. Subjects were administered 250 mg of HCA or placebo as a control (CON) for 5 d, after each time performing cycle ergometer exercise at 60% VO2max for 60 min followed by 80% VO2max until exhaustion. Blood was collected and expired gas samples analyzed at rest and every 15 min. The respiratory exchange ratio was significantly lower in the HCA trial than in the CON trial (p < 0.05). Fat oxidation was significantly increased by short-term administration of HCA, and carbohydrate oxidation was significantly decreased (p < 0.05) during exercise, presumably resulting in increasing the cycle ergometer exercise time to exhaustion after 1 h of 60% VO2max exercise (p < 0.05). These results suggest that a short-term administration of HCA enhances endurance performance with increasing fat oxidation, which spares glycogen utilization during moderate intensity exercise in athletes.