Changes of energy metabolism,myosin light chain composition,lactate dehydrogenase isozyme pattern and fibre type distribution of denervated fast-twitch muscle from rabbit after low frequency stimulation

The influence of low frequency (8–10 Hz) electrical stimulation on denervated fast-twitch muscle from rabbit was investigated. Prolonged direct stimulation of denervated muscle resulted in higher oxidative enzyme activities. Furthermore, single fibre analyses for succinate dehydrogenase showed a more uniform distribution of activity in stimulated-denervated muscle when compared to normal muscle. As was also the case following stimulation of innervated muscle, glycolytic enzymes were decreased in activity and the LDH-isozyme pattern also shifted towards heart type. No change of the myosin light chain pattern could be observed after 56 days of stimulation.This study was supported by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 138, and by grant NI 204-2-2. H. R. is grateful to Dr. Dirk Pette for his guidance and encouragement during this work, which was done in Dr. Pette's laboratory at the University of Konstanz     

The energetics of middle-distance running

Summary In order to assess the relative contribution of aerobic processes to running velocity (v), 27 male athletes were selected on the basis of their middle-distance performances over 800, 1500, 3000 or 5000 m, during the 1987 track season. To be selected for study, the average running velocity corresponding to their performances had to be superior to 90% of the best French of the season. Maximum O₂ consumption and energy cost of running (C) had been measured within the 2 months preceding the track season, which, together with oxygen consumption at rest allowed us to calculate the maximalv that could be sustained under aerobic conditions: . The treadmill runningv corresponding to a blood lactate of 4 mmol·^–1 (v _la4), was also calculated. In the whole group, C was significantly related to height (r=–0.43;P<0.03). Neither C nor (with, in this case, the exception of the 3000 m athletes) were correlated to . On the other hand,v _{a max} was significantly correlated to over distances longer than 800 m. These were also correlated tov _la4. Howeverv _la4 occurred at 87.5% SD 3.3% ofv _{a max}, this relationship was interpreted as being an expression of the correlation betweenv _{a max} and . Calculation ofv _{a max} provided a useful means of analysing the performances. At the level of achievement studied, sustained over 3000 m corresponded tov _{a max}. The shape of the relationship ofv/v _{a max} as a function of the duration of the event raised the question of a possible change in C as a function of v during middle-distance running competitions.     

大鼠肝再生中糖代谢相关基因的表达变化

目的了解糖类代谢相关基因在大鼠肝再生中的表达变化。方法本研究用搜集网站资料和查阅相关论文等方法获得糖类代谢相关基因,用大鼠基因组230 2.0芯片检测它们在大鼠再生肝中的表达情况,用比较手术组和假手术组中基因表达的差异性确定肝再生相关基因。结果初步证实上述基因中118个基因与肝再生相关。肝再生早期[部分肝切除(PH)后0.5~4h]、前期(PH后4~12h)、中期(PH后16~66h)和后期(PH后72~168h)等4个阶段起始表达的基因数为33、6、68和7;基因的总表达次数为68、44、210和83。表明肝再生相关基因主要在肝再生启动阶段起始表达,在不同阶段发挥作用。它们共上调205次,下调200次,分为12种表达方式,表明肝再生中糖代谢活动多样和复杂。其中,单糖和糖原代谢、糖蛋白和糖脂(主要为神经节苷脂)合成相关基因几乎在整个肝再生中表达增强,寡糖和糖胺聚糖合成及糖蛋白和糖脂分解相关基因表达下调。结论肝再生与糖代谢密切相关。     

遗传性果糖不耐受症

遗传性果糖不耐受症（HFI）是一种罕见的、由于先天性醛缩酶B缺陷导致的果糖代谢病。为常染色体隐性遗传性疾病。特征是摄取果糖、蔗糖或山梨醇后发生严重的低血糖。若不及时终止此类食物，会导致肝肾功能损伤及生长发育障碍。本病诊断比较困难，治疗主要以对症治疗和饮食控制为主。本文就遗传性果糖不耐受症的临床生化特征、诊治方法及醛缩酶B损伤的分子学基础进行综述，为临床早期发现、早期诊断、早期治疗遗传性果糖不耐受症提供参考。     

脂类代谢和运输涉及的基因与大鼠肝再生的相关性分析

目的在基因转录水平了解脂类代谢和运输相关基因在大鼠肝再生(LR)中的表达变化和模式。方法用搜集网站资料和查阅相关论文等方法获得参与脂类代谢和运输基因,用大鼠基因组230 2.0芯片检测它们在大鼠再生肝中的表达情况,用比较手术和假手术中基因表达的差异性确定肝再生相关基因。结果初步证实上述基因中193个基因与肝再生相关。肝再生早期[部分肝切除(PH)后0.5~4h]、前期(PH后6~12h)、中期(PH后12~66h)、后期(PH后72~168h)等4个阶段起始表达的基因数为113、20、66和1;基因的总表达次数为250、205、796和293。共上调852次,下调630次,分为27种表达方式。肝再生早期和前期胆汁酸代谢相关基因转录减弱;早期和后期糖皮质激素分解相关基因转录增强;前期和中期磷脂合成相关基因转录增强,磷脂分解相关基因转录减弱;中期脂肪酸、白三烯和鞘糖脂合成相关基因转录增强,甘油三酯和磷脂酰肌醇代谢相关基因转录增强,鞘糖脂分解相关基因转录减弱;中期和后期前列腺素合成和脂肪酸分解相关基因转录增强;几乎在整个肝再生中性激素、糖皮质激素和孕酮合成相关基因转录增强,鞘磷脂代谢相关基因转录增强,脂类运输相关基因转录增强,胆固醇代谢相关基因转录减弱。结论肝再生中脂类代谢和运输变化较大,与肝再生密切相关。     

The anaerobic recovery of frog muscle

Summary The muscle may undergo a partial recovery of its high energy phosphate stores in the absence of oxygen by the way of glycolysis (anaerobic recovery). This process has been studied in 41 pairs of frog gastrocnemii at different degrees of exhaustion induced by variable trains of supramaximal stimuli. Anaerobic recovery appears to be inadequate to replenish the fraction of muscle high energy phosphate stores (GP=ATP+PC) split as a consequence of the stimulation. The maximal amount of recovery (on the average about 5 Moles of GP per gram of fresh tissue) occurs when the muscle resting stores have been reduced to about 50%. This limitation in the extent of recovery is not a consequence of a reduced availability of glycogen but it is possibly related to the production of some metabolic intermediate, limiting the rate of the glycolytic sequence, likely the accumulation of lactic acid in the fiber. The time course of the anaerobic recovery process is characterized by at1/2 of about 2 min. The efficiency of the process, i.e. the number of the high energy phosphate bonds resynthesized by one Mole of lactic acid, appears to vary between 1.5 and 1.8, being of the same order of magnitude as the GP/L.A. ratio obtained from muscle extracts.     

Metabolism of lymphocytes in mice with Ehrlich ascites carcinoma

The pattern of metabolic processes in lymphocytes of mice with Ehrlich ascites carcinoma depended on the stage of tumor growth.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 11, pp. 563–566, November, 2004     

三氧化二砷对皮肤成纤维细胞、中性粒细胞MMPs活性,TIMP-1及TGF-β1表达的影响

目的：砒石是化腐生肌的常用中药，其主要成分是三氧化二砷（As₂O₃）。本研究通过观察As₂O₃对基质金属蛋白酶（MMPs）活性、基质金属蛋白酶组织抑制因子-1（TIMP-1）及转化生长因子β₁（TGF-β₁）表达影响，探讨化腐中药能否调节胶原代谢，从而治疗慢性皮肤溃疡。方法:明胶酶谱法检测大鼠中性粒细胞（PMNs）来源的MMP-9活性、人成纤维细胞（hFb）分泌的MMP-1、MMP-2的活性，免疫细胞化学法检测hFb TIMP-1、TGF-β₁的表达。结果:As₂O₃浓度在50 mg/L时可以提高大鼠PMNs来源的MMP-9的活性（P<0.01）；在0.8 mg/L可以提高hFb分泌的MMP-1、MMP-2的活性（分别P<0.01）；同时As₂O₃作用于hFb 6 h、12 h、18 h后，TIMP-1、TGF-β₁表达持续降低（P<0.01）。结论:As₂O₃在一定范围内可提高PMNs来源的MMP-9的活性；也可提高hFb分泌的MMP-1、MMP-2的活性，同时抑制hFbTIMP-1、TGF-β₁的表达。提示砷类制剂可通过提高多种MMPs的活性，降低TIMP-1的表达从而发挥化腐作用。     

Renewal of the membrane complex of Schistosoma mansoni is closely associated with lipid metabolism

Metabolic pathways leading to lipid biosynthesis in four different developmental stages of Schistosoma mansoni were explored and quantified by incubation in the presence of labeled precursors in a chemically defined medium. At the schistosomulum stage and in male, female, or paired worms, glycerol and oleate incorporation into neutral lipids, mainly in the form of triacylglycerols, was greater than into phospholipids, whereas in 11-and 15-day-old worms, synthesis mainly led to phospholipids. Incorporation into phospholipids was recovered largely in phosphatidylcholine, and distribution into other phospholipids depended on the developmental stage. Incorporation of choline and ethanolamine into their respective phospholipids represented up to 15% of the parasitic phospholipid content. The formation of phosphatidylcholine by phosphatidylethanolamine methylation occurred mainly in the immature parasitic stages. Inositol incorporation was also measurable, whereas [14C]serine incorporation was low or undetectable. Addition of 1-palmitoyl-2-[14C]oleyl phosphatidylcholine revealed a very high uptake of this phospholipid by the immature stages but further metabolism was not detectable. In contrast, adult S. mansoni were completely unable to take up or absorb this exogenous phospholipid. The most striking aspect of this study was the relatively high metabolic activity in 11-day-old worms and the lower but sustained activity on day 15 and at the schistosomulum stage. By comparison, biosynthetic activity in adult S. mansoni, on which research studies have been focused until now, was very low. We also discuss the participation of lipid metabolism in the constant renewal of the membrane complex which is essential to parasitism by S. mansoni.