Muscle and liver glycogen,protein, and triglyceride in the rat

Summary We have previously found that during exercise net muscle glycogen breakdown is impaired in adrenodemedullated rats, as compared with controls. The present study was carried out to elucidate whether, in rats with deficiencies of the sympatho-adrenal system, diminished exercise-induced glycogenolysis in skeletal muscle was accompanied by increased breakdown of triglyceride and/or protein. Thus, the effect of exhausting swimming and of running on concentrations of glycogen, protein, and triglyceride in skeletal muscle and liver were studied in rats with and without deficiencies of the sympatho-adrenal system. In control rats, both swimming and running decreased the concentration of glycogen in fast-twitch red and slow-twitch red muscle whereas concentrations of protein and triglyceride did not decrease. In the liver, swimming depleted glycogen stores but protein and triglyceride concentrations did not decrease. In exercising rats, muscle glycogen breakdown was impaired by adrenodemedullation and restored by infusion of epinephrine. However, impaired glycogen breakdown during exercise was not accompanied by a significant net breakdown of protein or triglyceride. Surgical sympathectomy of the muscles did not influence muscle substrate concentrations. The results indicate that when glycogenolysis in exercising muscle is impeded by adrenodemedullation no compensatory increase in breakdown of triglyceride and protein in muscle or liver takes place. Thus, indirect evidence suggests that, in exercising adrenodemedullated rats, fatty acids from adipose tissue were burnt instead of muscle glycogen.     

The metabolic response to prolonged walking in fed and fasted men

Summary Six healthy men walked 37 km (23 miles) per day over a 3-lap course for each of 4 consecutive days. Subjects were allowed breakfast and an unrestricted diet was consumed after completion of the walk, but no food was consumed during or between laps. At a later date the same subjects walked over the same course after an overnight fast and without breakfast. Completion time for each lap was 139±1 min (mean ±SE) and exercise intensity was equivalent to 17±1% . Mean 24h energy intake was 14.5±0.8 MJ during the fed walk. Estimated daily energy expenditure was 12.0 MJ. Blood glucose concentration fell significantly on the first, third and fourth days of the fed walk, but no subject became hypoglycaemic. Glucose concentration did not fall during the fasted walk and was significantly higher pre-exercise and at the end of laps one and three when compared to the first day of the fed walk. Blood alanine concentration fell significantly after the end of the first lap of each day of the fed walk but not during the fasted walk. Blood lactate levels did not change during the course of either walk. Plasma free fatty acid, glycerol and blood 3-hydroxybutyrate concentrations were unchanged during the passage of the first lap on each day of the fed walk, but all three had increased significantly by the end of the first lap of the fasted walk. The elevations from rest to the end of each day's walking for these three metabolites were of similar magnitude when comparing each day of the fed walk and the fed and fasted walks. The present experiment indicates that feeding a mixed diet can affect the pattern of substrate mobilization in a similar manner to that seen during more strenuous exercise. It also appears that the pattern of fuel substrate mobilization is very similar from one day to the next providing dietary intake is similar.     

The effects of induced alkalosis on the metabolic response to prolonged exercise in humans

To examine the effects of alkalosis on the metabolic response to prolonged exercise, seven healthy males cycled for 1 h at approximately 70% of maximum oxygen uptake on two occasions, 1-week apart. Starting 3 h prior to exercise, subjects consumed either CaCO₃ (placebo) or NaHCO₃ (0.3 g · kg^–1 body mass) over a 2-h period. Arterialised-venous blood samples were drawn before and during exercise for the determination of acid-base status and blood metabolites (lactate, glucose, glycerol and plasma free fatty acids). Expired gas was collected during exercise for determination of oxygen uptake and respiratory exchange ratio to estimate fuel oxidation rates. Ratings of perceived exertion (RPE) and heart rates were also recorded. A significant (P < 0.01) alkalosis was observed at all times following bicarbonate ingestion. Blood lactate was significantly (P < 0.05) higher at all sample times throughout exercise following bicarbonate ingestion. Blood lactate concentration [mean (SEM)] reached peak values of 2.90 (0.16) and 4.24 (0.45) mmol · l^–1 following 20 min of exercise following placebo and bicarbonate, respectively. No differences between treatments were noted at any time for the other metabolites. and RPE were significantly higher (P < 0.01) with the bicarbonate trial. At a constant power output increases in are generally associated with increases in fat oxidation, however, no evidence for an altered fuel oxidation was obtained in the present study. The differences in blood lactate indicate that induced alkalosis increased lactate efflux from muscle, but it cannot be confirmed whether this represents an increased rate of glycolysis within the muscle.     

Long-term effects of eliglustat on skeletal manifestations in clinical trials of patients with Gaucher disease type 1

PurposeMost patients with Gaucher disease have progressive and often disabling skeletal manifestations. We examined the long-term effect of eliglustat treatment on bone outcomes in clinical trials in adults with Gaucher disease type 1.MethodsData from 4 completed phase 2 and 3 trials were evaluated in treatment-naïve patients or patients switching to eliglustat from enzyme replacement therapy (ERT).ResultsOverall, 319 of 393 (81%) eliglustat-treated patients remained in their trials until completion or commercial eliglustat became available. Mean eliglustat treatment duration ranged from 3.3 to 6.5 years. In treatment-naïve patients and ERT-switch patients, frequency and severity of bone pain decreased during eliglustat treatment. Mean lumbar spine T-scores shifted from abnormal to normal in treatment-naïve patients and remained in the healthy reference range or improved modestly in ERT-switch patients. Mean total bone marrow burden score shifted from marked-to-severe to moderate in treatment-naïve patients and remained moderate in ERT-switch patients. MIP-1β (marker of active bone disease) was elevated at baseline and decreased to the healthy reference range in treatment-naïve patients and remained in the healthy reference range among ERT-switch patients.ConclusionThese findings confirm the long-term efficacy of eliglustat on skeletal complications of Gaucher disease in treatment-naïve and ERT-switch patients.     

Phospholipase C from Pseudomonas aeruginosa and Bacillus cereus:characterization of catalytic activity

Objective:To study characteristics of phospholipases C(PLCs),their importance for producing microorganisms us well us the potential of their use for industrial purposes.Methods:PLC from Bacillus cereus(B.cereus) D101 was selected as an example of Gram-positive PLCs and PLC from Pseudomanas aeruginosa(P.aeruginosa) D183 of Gram-negative ones.Enzymes were partially purified by ammonium sulfate precipitation followed by membrane dialysis.Partially purified preparations were used to study effect of different factors on activities as well as in substrate specificity tests which were conducted using a turbidimetric assay method.Results:Maximum activity was at pH 7 and 8 and 40 ℃ for P.aeruginosa PLC,and pH 8-10 and 37 ℃ for B.cereus PLC.Both PLCs were inhibited by Pi at 5 mM or higher,whereas,PLC from B.cereus only was inhibited by EDTA.Activity of P.aeruginosa PLC was not affected by removing Zn~(2+) ions from reaction mixture or their replacement with Ca~(2+),Ba~(2+),Mg~(2+) or Mn~(2+)ions.Vis-a-vis,activity of B.cereus PLC was found to be metal ion dependent PLCs from both isolates were relatively thermostable and showed maximum affinity toward phosphatidylcholine.Sphingomyelin and phosphatidylethanolamine were not good substrates and phosphatidylinositol,phosphatidylserine,phosphatidylglycerol and cardiolipin could be considered nonsubstrates.Conclusions:Human body physiological conditions could favor activity of P.aeruginosa and B.cereus PLCs.These enzymes may participate in phosphate scavenging and virulence of producing isolates but not in autolysis.PLCs from both isolates are potential candidates for industrial use.     

Measurement Of Angiotensinogen In Human Serum By Fluorescence Polarization Immunoassay

Fluorescence polarization immunoassay (F.P.I.A.) has rarely been used to measure components of the renin system. Using an Abbott TDX polarimeter and fluorescein - labelled angiotensin I as a tracer we measured angiotensin I by F.P.I.A. Combining this procedure with a renin incubation step enabled measurement of angiotensinogen in human serum. Using sera from male patients and from pregnant females, a good correlation between radioimmunoassay (R.I.A.). and F.P.I.A. was found. Two procedures were developed; one involving taking samples from the renin incubation mixture, the other involving measurement of generated angiotensin I at intervals without interrupting the renin incubation procedure. F.P.I.A. is less expensive and somewhat simpler than R.I.A. but, with the instrument used, it     

Linear lesions for treating the recurrence of persistent atrial tachyarrhythmia after cryoballoon ablation of atrial fibrillation

Overall, 133 patients underwent 170 procedures for the treatment of persistent ATa following an index cryoballoon pulmonary vein isolation (n = 715). After all the procedures, > 90% of the patients had a roof line, a mitral isthmus and/or septal line, and a cavotricuspid isthmus line. Ninety-two patients (69.2%) were in sinus rhythm after a median of 36 months since the index cryoballoon PVI. ATa: atrial tachyarrhythmia; cryo: cryoballoon; CTI: cavotricuspid isthmus; LSPV: left superior pulmonary vein; LIPV: left inferior pulmonary vein; PVI: pulmonary vein isolation; RF: radiofrequency; RSPV: right superior pulmonary vein; RIPV: right inferior pulmonary vein.

     

The effect of astaxanthin supplementation on performance and fat oxidation during a 40 km cycling time trial

ObjectivesThis study aimed to investigate whether supplementation with 12 mg?day^?1 astaxanthin for 7 days can improve exercise performance and metabolism during a 40 km cycling time trial.DesignA randomised, double-blind, crossover design was employed.MethodsTwelve recreationally trained male cyclists (VO_2peak: 56.5 ± 5.5  mL?kg^?1?min^?1, W_max: 346.8 ± 38.4  W) were recruited. Prior to each experimental trial, participants were supplemented with either 12 mg?day^?1 astaxanthin or an appearance-matched placebo for 7 days (separated by 14 days of washout). On day 7 of supplementation, participants completed a 40 km cycling time trial on a cycle ergometer, with indices of exercise metabolism measured throughout.ResultsTime to complete the 40 km cycling time trial was improved by 1.2 ± 1.7% following astaxanthin supplementation, from 70.76 ± 3.93 min in the placebo condition to 69.90 ± 3.78 min in the astaxanthin condition (mean improvement = 51 ± 71 s, p = 0.029, g = 0.21). Whole-body fat oxidation rates were also greater (+0.09 ± 0.13 g?min^?1, p = 0.044, g = 0.52), and the respiratory exchange ratio lower (?0.03 ± 0.04, p = 0.024, g = 0.60) between 39–40 km in the astaxanthin condition.ConclusionsSupplementation with 12 mg?day^?1 astaxanthin for 7 days provided an ergogenic benefit to 40 km cycling time trial performance in recreationally trained male cyclists and enhanced whole-body fat oxidation rates in the final stages of this endurance-type performance event.     

基底硬度对肝细胞和肝癌细胞融合生长的影响

目的通过比较融合生长肝细胞(L02)与肝癌细胞(HCCLM3)对不同硬度基底(0.5、4 kPa和玻璃)的响应,探查两类细胞融合生长差异的成因。方法运用实时显微摄影技术、免疫荧光染色、流式细胞技术及Western Blot-ting等试验方法分别检测融合生长L02和HCCLM3细胞在不同硬度基底上的形态特征、骨架构象、E-cad和Integrinβ1表达分布,以及Src激酶活性水平的变化。结果 (1)融合生长L02细胞呈圆形或立方形,HCCLM3细胞呈多角形,铺展和极化更为明显;随基底硬度增加,L02细胞圆度随时间变化幅度较小,HCCLM3细胞变化幅度较大。(2)融合生长的L02细胞皮质下呈现环形骨架,E-cad定位于细胞-细胞接触处,HCCLM3中皮质骨架环不完整,胞内骨架沿基底呈放射状分布,E-cad呈弥散分布于细胞质中。(3)随基底硬度增加,L02和HCCLM3细胞中E-cad表达显著降低(P<0.01),而p-Src和Integrinβ1的表达量则显著增加(P<0.01),HCCLM3较L02细胞变化明显。结论皮质下环形骨架装配与E-cad在细胞-细胞定位呈正相关,基底硬度对肝癌细胞钙黏素与整合素黏附系统平衡调节的影响较对肝细胞的影响明显。     

Oxidation of palmitate and lactate by beating myocytes isolated from adult dog heart.

Myocytes were isolated from hearts of adult dogs by repeated digestion with collagenase and hyaluronidase in Ca²⁺-free phosphate buffer followed by centrifugation in the presence of Ficoll. The isolated myocytes were free of other tissue elements and were contracting autorhythmically. The oxidation of palmitate and lactate were studied by incubating cell preparation with [1-¹⁴C]palmitate or [U-¹⁴C]lactate either in the presence or absence of CaCl₂ for 30 min at 37°C. [¹⁴C]O₂ was collected by KOH-soaked filter paper. Cardiac myocytes oxidized 0.1 to 0.18 nmol/mg protein min of palmitate and 1.5 to 2.2 nmol/mg protein min of lactate. The oxidation was linear for 75 min. Maximal rate of oxidation was obtained at substrate concentrations of 0.2 mm palmitate or 5.0 mm lactate. Adenine or pyridine nucleotides had no effect on the oxidation of these substrates. Palmitate oxidation was enhanced by carnitine and also by an increase in the molar ratio of palmitate/albumin, but was depressed (15 to 50%) by CaCl₂ (0.025 to 1.0 mm). CaCl₂ (0.05 to 1.0 mm) increased the rate of lactate oxidation by 50 to 68%. Lactate oxidation was also enhanced (68 to 87%) in the presence of palmitate (0.4 to 0.8 mm). These findings demonstrate the suitability of isolated adult heart myocytes for the study of cardiac metabolism.