Role of L-arginine uptake mechanisms in renal blood flow responses to angiotensin II in rats

Aim: Reduced muscle force greater than expected from loss of muscle mass has been reported in ageing muscles. Impaired sarcoplasmic reticulum (SR) Ca²⁺ release has been implicated as a possible mechanism, and attributed to several factors, including loss of ryanodine receptor (RYR) expression and protein binding. The aim of this study was to evaluate muscle quality and SR Ca²⁺ release in ageing rats that were not so old that major atrophy had occurred. Methods: We collected in situ force data from the plantarflexor muscle group and muscle mass from the constituent muscles to determine muscle quality (force/mass) in adult (6–8 months) and ageing (24 months) rats (n = 8/group). We evaluated SR Ca²⁺ uptake and release, and determined expression of key proteins associated with Ca²⁺ release [RYR and FK506 binding protein (FKBP)] and uptake (SERCA, parvalbumin, calsequestrin). Results: Plantarflexor force and muscle quality were reduced with ageing (approx. 28 and 34%, respectively), but atrophy was limited, and significant only in the medial gastrocnemius (approx. 15%). The fast phase of SR Ca²⁺ release was reduced with ageing in both gastrocnemii, as was FKBP expression and FKBP–RYR binding, but RYR expression was not affected. Similar, but non‐significant changes were present in the plantaris, but the soleus muscle generally showed no ageing‐related changes. Conclusion: These data suggest a possible role for impaired SR Ca²⁺ release in ageing‐related loss of muscle quality, although not through loss of RYR expression.     

Application of low dose of FK506 in pancreas transplantation model in Wistar-SD rats

Objective: To probe into application of low dose of FK506(Tacrolimus) in pancreas transplantation.

Methods: Effects of low-dose FK506 (Tacrolimus) in pancreas transplantation with examination of ELISA Electron microscopy and TUNEL by method of random control were studied.

Results: Blood glucose concentration in control group is higher than that in treated group A (FK506) and treated group B (CsA) 7 days after transplantation (p?<?0.05). Serum C-peptide and insulin concentrations in control group are less than that in treated group A (FK506) and treated group B (CsA) 7 days after transplantation (p?<?0.05). Blood glucose, serum C-peptide and insulin concentrations are same as that in control group, group A (FK506) and group B (CsA) (p?>?0.05).There are more apoptotic nuclei in control group than that in treated group A (FK506) and treated group B (CsA) (p?<?0.05). There is no significant difference between group A (FK506) and treated group B (CsA) in sum of apoptotic nuclei (p?>?0.05). There is no significant difference among treated group A (FK506) and treated group B (CsA) in electron microscopy fields.

Conclusion: Low-dose FK506 applied in pancreas transplantation could not only be effective for immunosuppressive, but also be safe for islet cells of pancreas.     

多元分析模板图在监测肝移植受者FK506治疗窗浓度中的应用

目的:应用多元分析模板图为临床肝移植受者监测他可莫司(代号FK506)理想治疗窗浓度提供方法。方法:用Excel软件建立标准品、质控品和患者样本的多元分析模板图,对微粒子酶免疫分析法(MEIA)测定的肝移植受者全血FK506血药浓度数据进行处理。结果:为11例肝移植受者检测FK506血药浓度178例次,术后3个月内在理想治疗窗浓度范围内者占44.6 %,异常标准曲线5条,质控值失控3次。结论:多元分析模板图操作简单,使用方便,是监测FK506治疗窗浓度的实用工具。     

Anti-arthritic properties of FK506 on collagen-induced arthritis in rats

Objective and design:To determine the effect of FK506 (tacrolimus) on paw inflammation, TNF- expression in joint, and bone and cartilage destruction in type II collagen-induced arthritis (CIA) model in rats.Methods:CIA was induced by immunization of female Lewis rats with an emulsion of bovine type II collagen and incomplete Freunds adjuvant. Paw inflammation was assessed by the increase in paw volume. Tumor necrosis factor (TNF) - expression in hind knee joint was assessed by immunohistochemical analysis. Lesions of bone and cartilage were assessed on the basis of histological change in knee joint, radiographic analysis in hind paw, bone mineral density in femora and proteoglycan contents in the cartilage of femoral heads. FK506 at doses of 1, 1.8 and 3.2 mg/kg or its placebo formulation was orally administered to rats for 28 days from the day after immunization (n = 10). Effect of FK506 was compared with that of vehicle (distilled water).Results:FK506 at a dose of 1.8 mg/kg significantly suppressed paw swelling (p < 0.01) and histological change in knee joint (p < 0.05). Tumor necrosis factor (TNF)- was mainly expressed in the region with a marked infiltration of inflammatory cells in the hind knee joint. FK506 (3.2 mg/kg) markedly reduced TNF- expression. FK506 at a dose of 1.8 mg/kg suppressed radiographic changes in hind paw (p < 0.05) and also recovered the decrease in bone mineral density in the femora (p < 0.05). Proteoglycan contents in the cartilage of femoral heads were determined to evaluate the cartilage destruction more quantitatively and found to significantly decrease in CIA rats. FK506 at a dose of 1.8 mg/kg recovered the loss of proteoglycan contents (p < 0.01).Conclusion:These results show that FK506 is effective in suppressing inflammation, TNF- expression in joint, and damage to bone and cartilage in rat CIA, and may be useful in the treatment of rheumatoid arthritis.     

Influence of FK506 and cyclosporin A on alloantibody production and lymphocyte activation following blood transfusion.

The effect of administration of cyclosporin A (CyA) or the novel macrolide FK506 was investigated in AO rats given DA blood transfusions. CyA (10 mg/kg, orally) or FK506 (1 mg/kg, intramuscularly) administered for 14 days from the time of transfusion effectively inhibited primary anti-MHC class I alloantibody production. This profound inhibitory effect persisted throughout the 2-month investigation period, with little increase in 'secondary' alloantibody production following a challenge injection 28 days after drug withdrawal. Flow cytometric analysis revealed no significant differences in the absolute numbers of W3/25+ (CD4+), OX-8+ (CD8+) or OX-12+ (B lymphocytes), in either the spleen or peripheral blood of transfused compared with normal, untreated animals. However, a small but significant increase in the numbers of splenocytes expressing the activation marker OX-40 (activated CD4+ cells) was observed in transfused animals. Either CyA or FK506 significantly reduced the number of cells expressing OX-39 (interleukin-2 receptors) and OX-40. Treatment of transfused animals with CyA, but not FK506 for 14 days resulted in minor, transient reduction in peripheral blood OX-19+ and W3/25+ cells, while 'sparing' the OX-8+ cells; these changes were not observed in spleens. In contrast, the absolute spleen cell numbers of OX-19+, W3/25+ and OX-8+ cells were significantly reduced in transfused animals given 14 days of FK506 treatment, while the corresponding blood cells were unaffected. Induction of splenic lymphoproliferative responses by the T cell mitogen concanavalin A remained normal in animals receiving transfusion alone or with CyA. In contrast, profound inhibition of mitogenic responses was observed in FK506-treated animals and this inhibitory effect declined gradually following drug withdrawal. No non-specific suppressor cell activity was detected in the spleens of rats given transfusion alone or in CyA or FK506-treated transfused animals.     

Activation of MAP kinases,pp90rsk and pp70-S6 kinases in mouse mast cells by signaling through the c-kit receptor tyrosine kinase or FcϵRI: rapamycin inhibits activation of pp70-S6 kinase and proliferation in mouse mast cells

The high-affinity receptor for IgE, Fc_?RI, represents the major cell surface structure through which mast cells express immunologically specific secretory function. By contrast, the stem cell factor receptor (SCFR), which is encoded by c-kit, is essential for normal mast cell development. The signaling pathways initiated by the stimulation of mast cells through the Fc_?RI, which lacks intrinsic kinase activity, and the SCFR, a member of the receptor tyrosine kinase family, generally have been regarded to be distinct. We report here that mouse mast cells stimulated either with SCF or with IgE and specific antigen exhibit a remarkably similar pattern of activation of mitogen-activated protein kinases (MAPK), 90 kDa-S6 kinases (pp90^rsk), and pp70-S6 kinases (pp70-S6K). These results indicate that all three families of protein kinases are associated with the cell surface receptor-dependent activation of secretion, as well as proliferation, in mast cells. We also show that the immunosuppressant rapamycin, but not FK506, can inhibit both SCF-dependent pp70-S6 kinase activation and SCF-dependent proliferation in mouse mast cells, without suppressing IgE- and antigen-dependent mediator release. These findings suggest that the activation of pp70-S6 kinase represents an important link in the stimulation of cell proliferation by SCF. Our results also indicate that the intracellular signaling pathways initiated by stimulation of mast cells through the Fc_?RI or the SCFR exhibit more overlap than has previously been appreciated.     

Effect of cold isotonic glucose infusion on A-V nodal conduction.

His bundle electrograms were performed in eight patients with organic heart disease. Recordings were made at various rates utilizing right atrial pacing. A solution of 100 cc of iced cold 5% glucose and water was infused through a cardiac catheter placed at the level of the tricuspid valve. The P-A, A-H, H-Q and H-S intervals were determined before and immediately after the cold water infusion. A significant prolongation of the A-H interval occurred with negligible effects on the P-A, H-Q and H-S intervals. At the atrial pacing rate of 100/min the average A-H interval increased from the control value of 116 to 125 msec after the infusion (P less than 0.02); at the pacing rate of 140/min, the A-H interval increased from 147 to 158 msec (P less than 0.01). This represents an impairment in conduction through the atrioventricular node.     

Histomorphological and functional impacts of postoperative motor training in rats after allograft sciatic nerve transplantation under low‐dose FK 506

This study aimed to determine the effect of motor training on recovery after nerve transplantation under low‐dose FK 506. Rats (n = 30) of two strains were randomly assigned to three groups. Group I served as untreated controls; groups II and III received allograft transplants for reconstruction of the sciatic nerve and FK 506 (0.1 mg/kg/d). Nonoperated limbs served as intra‐animal controls. Group III received postoperative motor training. Functional and histomorphological outcomes were assessed by walking track analysis and by blob analysis for myelinization of nerve sections. Regeneration occurred in both groups II and III. The control sections of the nonoperated limbs in group III showed significantly higher myelinization compared with group I and II; regeneration of the operated side was superior in group II. With regard to postoperative motor training, no benefit could be seen; however, the impact of postoperative motor training on the nonoperated limb were identified. Muscle Nerve, 2009     

Neuroregenerative and neuroprotective actions of neuroimmunophilin compounds in traumatic and inflammatory neuropathies

Abstract

FK506 (tacrolimus, Prograf^®) is an immunosuppressant drug that also has profound neuroregenerative and neuroprotective actions independent of its immunosuppressant activity. The separation of these properties has led to the development of non-immunosuppressant derivatives that retain the neurotrophic activity. This review focuses on the peripheral nerve actions of these compounds following mechanical injury (nerve crush or transection with graft repair) and in models of inflammatory neuropathies. Whereas FK506 may be indicative for the treatment of inflammatory neuropathies where its immunosuppressive action would be advantageous, non-immunosuppressant derivatives represent a new class of potential therapeutic agents for the treatment of human neurological conditions in general. Moreover, these studies have led to the discovery of a novel mechanism whereby these compounds activate intrinsic neuroregenerative and neuroprotective pathways in the neuron.     

他克莫司和雷帕霉素对肝癌肝移植患者Foxp3+ Treg的影响及防治排斥反应的研究

目的 探讨免疫抑制剂他克莫司和雷帕霉素对肝癌肝移植受者Foxp3+ Treg产生的影响及其防治排斥反应的疗效.方法 自移植后第2个月到第12个月,每月采血,采用实时荧光定量PCR法检测他克莫司组和雷帕霉素组肝癌肝移植受者新鲜外周血单个核细胞中Foxp3 mRNA的表达水平,通过同期术后观察和实验室检查,比较两组受者间Foxp3 mRNA表达水平和急性排斥反应发生率的差异.结果 他克莫司组受者的外周血单个核细胞中Foxp3 mRNA表达水平(0.1032±0.0943)明显低于雷帕霉素组受者(1.2136±0.6738),差异有统计学意义(t=5.1610,P＜0.01);雷帕霉素组患者比同期他克莫司组受者术后急性排斥反应发生率明显减低,差异有统计学意义(x2=2.2222,P＜0.05).结论 他克莫司抑制了肝癌肝移植术后免疫耐受的诱导,而雷帕霉素可能参与了免疫耐受的诱导和维持;雷帕霉素对肝癌肝移植受者防治排斥反应的效果更好.