The role of sweat in maintaining the stimulation of effort homeostasis in horses

Sweat secretion was analyzed quantitatively and qualitatively in 20 horses after a 5 min. gallop at 450 m/min. The analysis revealed concentration of proteins 63.3 +/- 6.47 g/l, mainly albumins, a high level of sodium 254.43 +/- 62.84 mM/,l chloride 268.68 +/- 98.46 mM/l, potassium 98.95 +/- 49.62 mM/l and calcium 4.14 +/- 0.8 mM/l. A dependence was found between the protein concentration in serum and its quantity in sweat and between the level of potassium in sweat and its loss from the cells within a range 8.6 to 25.8 mM/l. The hypertonic horse sweat protects organism for excessive water loss, the loss taking place by imperceptible evaporation. The loss of body weight amounted to 5.64 +/- 2.36 kg and the loss with the sweat was only 1.56 kg. Besides its thermoregulation function, the sweat ensures a proper effort homeostasis-isoosmic and isoionic status.     

液压系统在高压状态下保压控制的设计

液压系统在高压下的保压控制很重要，本文介绍了采用光导卸荷控制保压，自动补压系统的工作原理及特点，此系统克服了溢流阀保压控制使油温升高的弊病。     

The role of the mutT gene of Escherichia coli in maintaining replication fidelity

Some general features of the respiratory chain and respiratory control were characterized in coupled mitochondrial preparations from Leishmania mexicana promastigotes. O2 uptake was sensitive to the electron-transfer inhibitors rotenone, flavone, malonate, 4,4,4-trifluoro-1-(2-thienyl) 1.3 butanedione (TTFA), antimycin A, 2n-nonyl-4-hydroxyquinoline-N-oxide (HQNO), myxothiazol, cyanide and azide. A high concentration of rotenone (60 microM) was required to inhibit O2 uptake effectively. Difference spectra revealed the presence of cytochromes (a + a3), b and c. Respiratory control was stimulated 2-fold by ADP with different exogenous oxidizable substrates. Calculated ADP/O ratios were consistent with the notion that ascorbate/N,N,N',N'-tetramethylphenylenediamine (TMPD)-linked and FAD-linked respiration proceeds, respectively, with one third and two thirds of the ATP producing capacity of NADH-linked respiration. State 3 was suppressed by the ATP synthase inhibitors oligomycin and aurovertin and by the adenine nucleotide translocator inhibitors atractyloside and carboxy atractyloside. The protonophore carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) provoked state 3u respiration. The mitochondrial preparation was capable of Ca2+ uptake and Ca2+ stimulated respiration. Data obtained suggests strongly that mitochondrial complexes I, II, III and IV are present in a major pathway of electron-transfer and that oxidative phosphorylation might proceed with high bioenergetic efficiency.     

The sodium-hydrogen exchange system in the heart: its role in ischemic and reperfusion injury and therapeutic implications

OBJECTIVES: To review evidence supporting a role for sodium-hydrogen exchange (Na/H exchange) in mediating myocardial ischemic and reperfusion injury, and to outline clinical implications in terms of the development of novel cardioprotection strategies. DATA SOURCES: Various sources were used including MEDLINE and Reference Update. Only articles written in the English language were used. DATA EXTRACTION: A wide range of publications dealing with cardiac injury and particularly studies involving intracellular pH regulation and Na/H exchange activity. The vast majority of papers cited were published since 1986, with a large percentage appearing within the past five years. DATA SYNTHESIS: Na/H exchange is a major mechanism for restoration of intracellular pH after ischemia, although its activation during both ischemia and reperfusion has been shown to be involved in a paradoxical induction of cell injury. This likely reflects the fact that activation of the exchanger is closely coupled to sodium influx and, as a consequence, to elevation in intracellular calcium concentrations through sodium-calcium exchange. In addition to intracellular acidosis, other factors can stimulate the exchanger, including various autocrine and paracrine factors such as endothelin-1 and activation of alpha 1 adrenergic receptors, both of which likely act through signal transduction processes including activation of protein kinase C. Although at least 5 Na/H exchange isoforms have been identified, it appears that subtype 1, termed NHE-1, is the predominant isoform in the mammalian myocardium. Effective pharmacological inhibitors of Na/H exchange, including those that are NHE-1 specific, have been developed. These have been extensively demonstrated to protect the ischemic and reperfused myocardium, as shown by improved systolic and diastolic function, preservation of cellular ultrastructure and reduced incidence of arrhythmias. Moreover, the salutary effects of these agents have been demonstrated by a variety of experimental models and animal species, suggesting that the role of Na/H exchange in mediating injury is not species-specific. CONCLUSION: Na/H exchange is an important target for pharmacological intervention in attenuation of ischemia- and reperfusion-induced cardiac injury. Coupled with the low potential for toxicity by the agents, Na/H exchange inhibition could emerge as an effective therapeutic strategy in cardiac disorders, particularly involving conditions associated with ischemia and reperfusion.     

Striatal efferent fibers play a role in maintaining rotational behavior in the rat

Rats in which ascending dopamine-containing neurons have been unilaterally destroyed by injections of 6-hydroxydopamine are known to rotate after being injected with apomorphine or L-dopa. The rotation is markedly reduced by either (i) ipsilateral electrocoagulations of the caudate-putamen or internal capsule or (ii) ipsilateral coronal knife cuts immediately rostral to the substantia nigra. Neostriatal efferent fibers, in particular the strionigral projection, appear to be required for the expression of this dopamine-dependent behavior.     

The role of dopamine in maintaining intracranial self-stimulation in the ventral tegmentum, nucleus accumbens, and medial prefrontal cortex.

Male albino Wistar rats were prepared with 2 chronic bipolar electrodes implanted ipsilaterally in the ventral tegmentum and either the nucleus accumbens or the medial prefrontal cortex. Once stable intracranial self-stimulation was elicited from both midbrain and forebrain electrodes, 6-hydroxydopamine lesions were placed into the ascending dopaminergic pathways between the rewarding electrode placements at the level of the lateral hypothalamus. Data suggest that dopamine plays an important role in self-stimulation in the ventral tegmentum and contributes to this behavior in the prefrontal cortex. Findings also show that nondopaminergic systems contribute to the phenomenon of brain-stimulation reward. (French summary) (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

监视和测量在质量管理体系中的作用

针对产品的监视和测量在质量管理体系中的作用,阐述了相应的认识和理解,对ISO 9000标准的进一步深入了解有一定指导意义.     

Effect of an antiandrogen on the lymphoid system

A side-effect of the administration of cyproterone acetate, an antiandrogenic steroid, to newborn, juvenile or adult male mice (in doses comparable to those used clinically) was found in a marked reduction of the white pulp of the spleen and reduced weight or even absence of the thymus.     

The role of adenosine in the central nervous system

Adenosine is one of the normal elements in body fluid including extracellular fluid within the CNS. Its normal level is 0.03-0.3 mumol/L. When ATP's metabolism loses balance, for example, during ischemia, the level of adenosine increases dramatically, may reach as much as 1000 times of the normal. Adenosine plays many physiological and pathological roles in CNS via its receptors. It is recognized as an inhibitory neuromodulator playing a neuroprotective role in CNS.     

关节镜的使用配合及保养

关节镜外科近年来有了飞速发展,它具有诊断准确性高、损伤性小的优点.关节镜手术是骨科微创手术,它通过关节部位2-3个各约5毫米的小切口,在电视监视器下便可看到关节内的病变,对患者的关节疾患进行观察与精细治疗.关节镜的适应证有:膝骨性关节炎、膝变型性关节炎、化脓性膝关节炎、膝关节结核,膝关节半月板损伤,膝关节前十字韧带损伤及后十字韧带损伤,膝关节游离体,膝关节类风湿性滑膜炎,风湿性关节炎,色素绒毛膜样滑炎,不明原因的膝关节炎.     

Endogenous synthesis of arginine plays an important role in maintaining arginine homeostasis in postweaning growing pigs

This study was conducted to determine whether endogenous synthesis of arginine plays a role in regulating arginine homeostasis in postweaning pigs. Pigs were fed a sorghum-based diet containing 0. 98% arginine and were used for studies at 75 d of age (28.4 kg body weight). Mitochondria were prepared from the jejunum and other major tissues for measuring the activities of Delta1-pyrroline-5-carboxylate (P5C) synthase and proline oxidase (enzymes catalyzing P5C synthesis from glutamate and proline, respectively) and of ornithine aminotransferase (OAT) (the enzyme catalyzing the interconversion of P5C into ornithine). For metabolic studies, jejunal enterocytes were incubated at 37 degrees C for 30 min in Krebs-Henseleit bicarbonate buffer containing 2 mmol/L L-glutamine, 2 mmol/L L-[U-14C]proline, and 0-200 micromol/L gabaculine (an inhibitor of OAT). The activities of P5C synthase, proline oxidase and OAT were greatest in enterocytes among all of the tissues studied. Incubation of enterocytes with gabaculine resulted in decreases (P < 0.05) in the synthesis of ornithine and citrulline from glutamine and proline. When gabaculine was orally administered to pigs (0.83 mg/kg body weight) to inhibit intestinal synthesis of citrulline from glutamine and proline, plasma concentrations of citrulline (-26%) and arginine (-22%) decreased (P < 0.05), whereas those of alanine (+21%), ornithine (+17%), proline (+107%), taurine (+56%) and branched-chain amino acids (+21-40%) increased (P < 0.05). On the basis of dietary arginine intake and estimated arginine utilization, the endogenous synthesis of arginine in the 28-kg pig provided >/=50.2% of total daily arginine requirement. Taken together, our results suggest an important role for endogenous synthesis of arginine in regulating arginine homeostasis in postweaning growing pigs, as previously shown in neonatal pigs.     

The role of ionic transporters in the long-term regulation of the water content in animal cells. The mathematical model and real lymphoid cells

Ion and water balance as well as flux balance in the animal cell, equilibrated to anisosmotic solutions, are computed for a cell model supplied by Na,K-ATPase pump, electroconductive ion channels and symporters Na-Cl, K-Cl and NaK2Cl. It is shown how the potency of each of the principal transporters to regulate cell volume depends on such conditions as the state of other ion transporters and channels, initial ion distribution and membrane potential. The obtained data are applied to studying changes in cation and water balance in the Jurkat lymphoid cells equilibrated to hyposmotic solutions. It is concluded that a steady state volume regulation in Jurkat cells, maintained in hyposmotic media 180 mosM for up to 24 h, is achieved due mainly to non-ionic mechanisms. Under the lower osmolarity of the media, 155 mosM, the ionic cell volume regulation occurs. The increase in PCl and/or the decrease in Na-Cl symport (or its equivalent, e.g. Na/H and Cl/HCO3 exchange) are considered as the most probable cause of the long-term volume decrease in lymphoid cells.     

The leukocyte cell adhesion cascade and its role in myocardial ischemia-reperfusion injury

Cell-cell and cell-matrix interactions are known to be mediated by specific cell adhesion receptors expressed on the cell surface. The characterization of these cell adhesion molecules has allowed researchers to examine their roles in a variety of physiologic and pathophysiologic conditions. Numerous studies have demonstrated that myocardial ischemia-reperfusion injury is an acute inflammatory process in which leukocytes are intimately involved. In this review, we summarize the current data on the leukocyte cell adhesion cascade, focus upon studies which have demonstrated specific cell adhesion molecule interactions which mediate the leukocyte involvement in myocardial ischemia-reperfusion injury and suggest future avenues of exploration and possible clinical implications of the studies reviewed.