TGFβ1及其Ⅰ,Ⅱ型受体在肾癌中的表达

目的 探讨肾癌中转化生长因子β１（ＴＧＦβ１）及其Ⅰ、Ⅱ型受体（ＴＧＦβ－Ｒ－Ｉ、ＴＧＦβ－Ｒ－ＩＩ）表达及其意义。方法 采用免疫组化技术（ＳＰ法）对４６例肾癌例,１１例正常肾组织ＴＧＦβ１、ＴＧＦβ－Ｒ－Ｉ、Ｒ－ＩＩ进行检测,结合临床资料进行分析。结果 肾癌组ＴＧＦβ１表达量较正常肾组高（Ｐ〈０．０５）;ＴＧＦβ－Ｒ－ＩＩ在肾癌组及正常肾组均表达;ＴＧＦβ－Ｒ－Ｉ在肾癌中阳性率较正常肾阳性率低（     

b-FGF在肾癌组织中表达的临床意义

目的 探讨ｂ－ＦＧＦ（碱性成纤维细胞生长因子）在肾癌中表达的临床意义。方法 采用斑点杂交技术和免疫组化技术测定２０例肾癌患者癌组织、癌旁和正常肾组织ｂ－ＦＧＦ表达情况。结果 肾癌组织中ｂ－ＦＧＦ表达明显高于癌旁和周围正常肾组织（Ｐ〈０．０１），ｂ－ＦＧＦ表达升高与肿瘤分期、分级密切相关，与肿瘤大小无明显关系。结论 ｂ－ＦＧＦ为肾癌组织自身分泌，与肾癌的发生和发展密切相关。     

肾癌患者TGF-β1表达和肿瘤微血管密度检测的临床意义

目的探讨转化生长因子β１（ＴＧＦβ１）在肾癌中的表达和肿瘤微血管密度（ＭＶＤ）与肿瘤侵袭的关系。方法采用免疫组化方法对３２例肾癌和６例正常肾组织进行ＴＧＦβ１多克隆抗体和第Ⅷ因子相关抗原（ＶＷＦ：Ａｇ）单克隆抗体染色。观察肾癌组织和正常肾组织ＴＧＦβ１表达与ＭＶＤ之间的相关性。结果ＴＧＦβ１在正常肾组织中仅１例呈阳性表达,而在肾癌组织中阳性表达２８例,两者之间差异有显著性（Ｐ＜０．００５）;肾癌组织中ＴＧＦβ１表达强度与肿瘤间质微血管密度之间存在正相关性;二者与肾癌周围组织有无侵袭存在显著相关性（Ｐ＜０．０５）,但与肿瘤大小无关（Ｐ＞０．０５）。结论ＴＧＦβ１表达是肾癌的恶性表型之一,且有可能促进肿瘤微血管的形成,上述二项指标对评估肾癌的预后有重要意义。     

TGFβ1及其I、II型受体在肾癌中的表达

目的探讨肾癌中转化生长因子β１（ＴＧＦβ１）及其Ｉ、Ｉ型受体（ＴＧＦβＲＩ、ＴＧＦβＲＩ）表达及其意义。方法采用免疫组化技术（ＳＰ法）对４６例肾癌,１１例正常肾组织ＴＧＦβ１、ＴＧＦβＲＩ、ＲＩ进行检测,结合临床资料进行分析。结果肾癌组ＴＧＦβ１表达量较正常肾组高（Ｐ＜０．０５）;ＴＧＦβＲＩ在肾癌组及正常肾组均表达;ＴＧＦβＲＩ在肾癌中阳性率较正常肾阳性率低（Ｐ＜０．０１）,ＴＧＦβＲＩ在高分期,高分级肾癌中表达阳性率较低分期、低分级肾癌低（Ｐ＜０．０５）;ＴＧＦβ１表达量低及ＴＧＦβＲＩ表达阴性肾癌者预后差。结论ＴＧＦβ１对肾癌是一种重要负性调节因子,可抑制肾癌进展,ＴＧＦβＲＩ缺失使ＴＧＦβ系统完整性受到破坏,ＴＧＦβ１失去负性调节作用。ＴＧＦβ１及ＴＧＦβＲＩ表达可做为判断肾癌预后的指标之一     

凋亡相关基因产物Fas/APO-1和bcl-2蛋白在肾癌组织中的表达及意义

目的研究凋亡相关基因Ｆａｓ／ＡＰＯ－１和ｂｃｌ－２在肾癌发生发展中的作用。方法采用免疫组织化学法对３５例肾癌组织和２６例远离肾癌的正常肾组织Ｆａｓ／ＡＰＯ－１和ｂｃｌ－２蛋白的表达进行检测。结果肾癌组织Ｆａｓ／ＡＰＯ－１蛋白表达率为５７．１４％，明显低于正常肾组织中的表达率（８４．６２％，Ｐ＜０．０５），且表达强度也明显低下；而ｂｃｌ－２蛋白表达率为８０．００％，明显高于正常肾组织中的表达率（５３．８５％，Ｐ＜０．０５）。结论Ｆａｓ／ＡＰＯ－１与ｂｃｌ－２基因共同参与了肾癌的发生和发展。     

Bcl－2／bax蛋白在肾癌组织中的表达意义

为探讨凋亡抑制基因ｂｃｌ－２和凋亡促进基因ｂａｘ蛋白在肾癌组织中的表达对肾癌发生和发展的影响，采用抗ｂｃｌ－２单克隆抗体和抗ｂａｘ多克隆抗体分别对４２例肾癌和２０例远离癌的正常肾组织的石蜡切片进行免疫组织化学染色。结果显示２０例正常肾组织有１１例ｂｃｌ－２蛋白呈弱阳性表达，阳性率５５．０％，表达部位在肾小管和集合管上皮细胞，４２例肾癌组织有３７例ｂｃｌ－２蛋白表达阳性，阳性率８８．１％，且染色强度明显增强。经统计学处理，肾癌组织阳性表达明显高于正常肾组织（Ｐ＜０．０１）。２０例正常肾组织有１９例ｂａｘ蛋白表达阳性，阳性率９５．０％，表达部位在肾小管和集合管上皮细胞。４２例肾癌组织有２２例ｂａｘ蛋白表达阳性，阳性率５２．４％。经统计学处理，肾癌组织阳性表达明显低于正常肾组织（Ｐ＜０．０１）。ｂｃｌ－２和ｂａｘ蛋白在肾癌组织中的异常表达，使肾癌细胞凋亡处于抑制状态，细胞寿命延长，可能参与了肾癌的发生和发展过程     

血管内皮生长因子在肾细胞癌中的表达及意义

研究肾细胞癌血管内皮生长因子（ＶＥＧＦ）的表达及其与肿瘤转移、分期、病理类型及预后的关系。采用抗ＶＥＧＦ的多克隆抗体免疫组织化学技术染色（ＬｓＡＢ法）研究６１例肾癌组织切片。结果显示：４５９％（２８／６１）的肾癌ＶＥＧＦ表达阳性，淋巴结和（或）血行转移的ＶＥＧＦ表达率（７７８％）明显高于非转移者（３２６％，Ｐ＜００１）；阳性表达者五年生存率（２９１％）明显低于阴性表达者（８４６％，Ｐ＜００１）；Ⅰ、Ⅱ期阳性表达低于Ⅲ、Ⅳ期（Ｐ＜００５）；但与性别、年龄及肿瘤的病理类型无关。ＶＥＧＦ除在癌细胞胞浆和胞膜表达外，尚表达于肿瘤基质血管和邻近肿瘤的正常肾小管胞浆、肾小球和血管内皮及血管平滑肌胞膜。认为ＶＥＧＦ除由肿瘤细胞合成外，可能尚表达于邻近肿瘤的正常肾小管胞浆，ＶＥＧＦ表达有助于肾癌预后判断及指导治疗，ＶＥＧＦ可能是肿瘤血管的良好标记物，设法抑制ＶＥＧＦ可望成为肾癌治疗的有效方法。     

Bcl—2／bax蛋白在肾癌组织中的表达意义

为探讨凋亡抑制基因ｂｃｌ－２和凋亡促进基因ｂａｘ蛋白在肾癌组织中的表达对肾癌发生和发展的影响，采用抗ｂｃｌ－２单克隆抗体和抗ｂａｘ多克隆抗体分别对４２例肾癌和２０例远离癌的正常组织的石蜡切片进行免疫组织化学染色，结果显示２０例正常肾组织有１１例ｂｃｌ－２蛋白呈弱阳性表达，阳性率５５．０％，表达部位在肾小管和集合管上皮细胞，４２例肾癌组织有３７例ｂｃｌ－２蛋白表达阳性，阳性率８８．１％，且染色强度明     

凋亡相关基因产物Fas／APO—1和bcl—2蛋白在肾癌组织中的表达及 …

目的 研究凋亡相关基因Ｆａｓ／ＡＰＯ－１和ｂｃｌ－２在肾癌发生发展中的作用。方法 采用免疫组织化学法对３５例肾癌组织和２６例远离肾癌的正常肾组织Ｆａｓ／ＡＰＯ－１和ｂｃｌ－２蛋白的表达进行检测。结果 肾癌组织Ｆａｓ／ＡＰＯ－１蛋白表达率５７．１４％,明显低于正常肾组织中的表达率（８４．６２％,Ｐ〈０．０５）,且表达强度也明显低下;而ｂｃｌ－２蛋白表达率为８０．０％,明显高于正常肾组织中的表达率（５     

Fas mRNA在泌尿系肿瘤组织中的表达

目的 了解Ｆａｓ ｍＲＮＡ在泌尿系肿瘤组织中的表达情况。方法 采用逆转录ＰＣＲ（ＲＴ－ＰＣＲ）法检测３７例泌尿系恶性肿瘤组织中Ｆａｓ ｍＲＮＡ的表达，其中肾癌２１例，膀胱癌１１例、肾盂癌４例，前列腺肉瘤１例；原位杂交法检测３４例肾癌和１９例癌旁正常肾组织中Ｆａｓ ｍＲＮＡ的表达。结果 ３７例肿瘤组织中检出Ｆａｓ ｍＲＮＡ阳性表达共２０例，阳性率为５４％，阳性表达组织中未发现有缺失突变的存在。其中肾     

Involvement of A1 adenosine receptors in the acquisition of fertilizing capacity

Ejaculated mammalian spermatozoa acquire competence to fertilize oocytes by a two-step process: capacitation followed by acrosome reaction. The biochemical and biophysical modifications occurring in vivo in the female reproductive tract can be reproduced in vitro, and previous studies have suggested a capacitative role for adenosine A(1) receptor (A(1)R). Mice with a targeted disruption of the Adora 1 gene (A(1)R-/- mice) provide a useful model for better understanding the role of the A(1)R in fertility. Murine spermatozoa express A(1)R in the head, neck, midpiece region, and tail. The number of capacitated spermatozoa incubated in human tubal fluid was significantly reduced in A(1)R-/- compared with A(1)R+/+ and A(1)R+/- spermatozoa. The difference between A(1) R+/+ and A(1)R-/- mouse spermatozoa was mainly in the time necessary to reach the maximum percentage of capacitation. A(1)R+/+ murine sperm obtained the full state of capacitation within 90 minutes whereas A(1)R-/- sperm required 240 minutes. Caffeine, a known antagonist of A(1) and A(2A) adenosine receptors, lowered the number of capacitated sperm and affected the time of capacitation in a dose-dependent manner, mimicking the effects of the lack of A(1) receptors. Although number, motility, and viability of A(1)R-/- murine sperm was not significantly different from A(1)R+/+ mouse spermatozoa, a significant reduction of the number of pups produced by A(1)R-/- male mice suggests that A(1) receptors must be fully operative to accomplish the optimal degree of capacitation and thereby fertilization.     

Inhibition of sphingosine 1-phosphate receptor 2 protects against renal ischemia-reperfusion injury

Activation of the sphingosine 1-phosphate receptor 1 (S1P(1)R) protects against renal ischemia-reperfusion (IR) injury and inflammation, but the role of other members of this receptor family in modulating renal IR injury is unknown. We found that a selective S1P(2)R antagonist protected against renal IR injury in a dose-dependent manner. Consistent with this observation, both S1P(2)R-deficient mice and wild-type mice treated with S1P(2)R small interfering RNA had reduced renal injury after IR. In contrast, a selective S1P(2)R agonist exacerbated renal IR injury. The S1P(2)R antagonist increased sphingosine kinase-1 (SK1) expression via Rho kinase signaling in renal proximal tubules; the S1P(2)R agonist decreased SK1. S1P(2)R antagonism failed to protect the kidneys of SK1-deficient mice or wild-type mice pretreated with an SK1 inhibitor or an S1P(1)R antagonist, suggesting that the renoprotection conferred by S1P(2)R antagonism results from pathways involving activation of S1P(1)R by SK1. In cultured human proximal tubule (HK-2) cells, the S1P(2)R antagonist selectively upregulated SK1 and attenuated both H(2)O(2)-induced necrosis and TNF-α/cycloheximide-induced apoptosis; the S1P(2)R agonist had the opposite effects. In addition, increased nuclear hypoxia inducible factor-1α was critical in mediating the renoprotective effects of S1P(2)R inhibition. Finally, induction of SK1 and S1P(2)R in response to renal IR and S1P(2)R antagonism occurred selectively in renal proximal tubule cells but not in renal endothelial cells. Taken together, these data suggest that S1P(2)R may be a therapeutic target to attenuate the effects of renal IR injury.     

L-精氨酸在人肝癌裸鼠肝脏移植瘤生长中的作用

目的 探讨L-精氨酸(L-arg)在人肝癌裸鼠肝脏移植瘤生长中的作用.方法 建立人肝癌裸鼠肝脏移植瘤模型,使用L-arg进行干预治疗,采用免疫组化方法 和图像分析技术检测增殖细胞核抗原(PCNA)的表达,原位末端标记(TUNEL)法检测肿瘤细胞的凋亡情况.结果 (1)小剂量L-arg(0.5 g·kg~(-1)·d~(-1))组、大剂量L-arg(1g·kg~(-1)·d~(-1))组和对照组移植瘤重量分别为(985±76)mg、(328±35)mg、(586±56)mg;大剂量L-arg组移植瘤重量较对照组显著减少(P＜0.05);小剂量L-arg组移植瘤重量较对照组显著增加(P＜0.05).(2)大剂量L-arg组移植瘤PCNA的表达较对照组显著下调(P＜0.05),小剂量L-arg组和对照组比较无明显差异(P＞0.05).(3)大剂量L-arg组NO水平较对照组和小剂量组显著升高(P＜0.05),小剂量L-arg较对照组显著升高(P＜0.05).(4)大剂量L-arg组移植瘤凋亡指数(AI)明显高于对照组(P＜0.05);小剂量L-arg对移植瘤AI无明显影响(P＞0.05).结论 L-精氨酸对肝癌具有双重作用.小剂量L-精氨酸可促进肝癌生长;大剂量L-精氨酸抑制肝癌的生长.     

Tiam1和Rac1表达与胃癌病理生物学行为的关系

目的　探讨T淋巴瘤侵袭转移诱导因子 1 (Tiam1 )和Ras相关的C3肉毒素底物 1 (Rac1 )表达与胃癌侵袭、转移间的关系。方法　应用链酶亲和素 -生物素过氧化物酶复合物 (SABC)免疫组化法检测 6 0例胃癌及癌旁胃黏膜组织中Tiam1和Rac1蛋白的表达,并分析其与胃癌临床病理参数间的关系。结果　 ( 1 )Tiam1蛋白在癌旁胃黏膜组织中染色均为阴性,在胃癌组织中 7 8. 3 3%染色呈阳性 (P< 0. 0 1 ); ( 2 )Rac1蛋白染色阳性率在胃癌组织中 ( 7 1. 6 7% )显著高于癌旁胃黏膜组织( 1 8. 3 3% ) (P< 0. 0 1 ); ( 3 )随胃癌组织分化程度的降低、浸润深度的增加、TNM分期的升高及淋巴结转移的发生,Tiam1和Rac1蛋白的染色阳性率皆升高 (P < 0. 0 5 )。但两者的表达水平与胃癌患者的性别、年龄、癌变原发部位及癌灶大小无关 (P > 0. 0 5 ); ( 4 )Tiam1阳性胃癌组织中的Rac1蛋白表达水平显著高于Tiam1阴性者 (P< 0. 0 1 )。结论　 ( 1 )Tiam1和Rac1的表达与胃癌浸润、转移密切相关; ( 2 )在胃癌组织中,Tiam1和Rac1的表达水平呈正相关; ( 3 )对Tiam1和Rac1的联合检测有助于预测胃癌的病理生物学行为。     

Comparison of Hypotensive Response following Intravenous Injection of Parathyroid Hormone 1-84 and 1-34 in Conscious Rats

Activation of parathyroid hormone 1 (PTH-1) receptors on vascular smooth muscle cells causes relaxation and decreases blood pressure in rats and humans. However, when PTH(1-84) and PTH(1-34) were injected in anesthetized rats, PTH(1-34) produced a greater decrease in blood pressure. This study quantified the dose-response relationship of the hypotensive response to intravenously injected PTH(1-84) and PTH(1-34) in conscious rats and assessed the role that the C-terminal region of PTH(1-84) played in the differences. Mean arterial pressure (MAP) decreased rapidly following injection of both peptides (0–100 nmol/kg) and reached a nadir at 1–2 minutes before increasing at a rate that was dose- and time-dependent. PTH(1-34) produced a greater hypotensive effect than PTH(1-84) at most doses tested and was significantly different from PTH(1-84) at 1–10 nmol/kg. The greatest difference in MAP decrease between PTH(1-84) and PTH(1-34) (24 and 35 mm Hg, respectively) occurred at 10 nmol/kg. Median effective dose (ED₅₀) values for PTH(1–84) and PTH(1-34) were significantly different (5.9 and 1.3 nmol/kg, respectively). The C-terminal PTH fragments PTH(7–84), PTH(39–84), and PTH(53–84) did not affect MAP when injected alone (10 nmol/kg), nor did they influence the hypotensive response when given at a 10–fold molar excess in combination with PTH(1-84) or PTH(1-34) (1.4 nmol/kg). In conclusion, PTH(1-84) is a less potent but, because it induced the same maximum response, not a less efficacious hypotensive agent than PTH(1-34) when administered by bolus intravenous injection in conscious rats. We found no evidence to support the concept that the C-terminal region of PTH is responsible for this difference in potency.     

Thiopental binding to human serum albumin in the presence of halothane

In vitro thiopental binding (substrate concentration 0.04.10(-3) M = 10 micrograms/ml) to 1% human serum albumin (HSA) increased significantly from 40.2% (= control) to 47.3% in the presence of 1.18.10(-3) M = 2.84 vol% halothane. A 4-fold higher halothane concentration (4.71.10(-3) M) had an even greater effect with an increase in the thiopental fraction bound to 55.5%. With a constant HSA concentration (1% or 5%) and thiopental concentrations in the range 0.01-1.5.10(-3) M or 0.01-0.38.10(-3) M, respectively, the halothane effect (increase in thiopental binding) was always evident, as well as in other experiments with constant thiopental concentration (0.04.10(-3) M) and variation in the HSA concentration (0.5-10%). Two classes of binding sites for thiopental were apparent at the HSA molecule. In the control experiments the following binding parameters were found: n1 = 0.01, k1 = 181.10(3) M-1; n2 = 45.73, k2 = 0.08.10(3) M-1, K = 5.47.10(3) M-1. In the presence of halothane the binding parameters changed as follows: n1 = 0.14, k1 = 29.4.10(3) M-1; n2 = 11.68, k2 = 0.42.10(3) M-1, K = 9.02.10(3) M-1.     

谷胱甘肽转硫酶基因多态性与湖北汉族人群溃疡性结肠炎的关系

目的 探讨谷胱甘肽转硫酶(GSTs)基因多态性与湖北汉族人群溃疡性结肠炎(UC)的关系.方法 回顾性分析2002年8月至2009年12月武汉大学中南医院、武汉大学人民医院、华中科技大学附属同济医院和协和医院收治的270例湖北汉族UC患者(UC组)及同期623例健康体检者(对照组)的临床资料.根据病变范围将UC患者分为远端UC组(229例)和广泛UC组(41例);根据病变严重程度将UC患者分为轻中度组(237例)和重度组(33例).采用聚合酶链反应检测GSTM1和GSTT1的基因多态性、采用限制性片段长度多态性聚合酶链反应检测GSTP1的基因多态性,并对GSTs基因型进行判定.将含有157 bp片段和480 bp片段者分别定义为GSTM1(+)和GSTT1(+),而无相应的扩增产物者分别定义为GSTM1(-)、GSTT1(-).采用x2检验对数据进行分析.结果 UC组和对照组中GSTM1(-)、GSTT1(-)和GSTP1纯合子突变型基因型(Val/Val)的分布频率分别为70.7%(191/270)、64.8%(175/270)、48.9%(132/270)和41.7%(260/623)、47.2%(294/623)、34.3%(214/623),两组比较,差异有统计学意义(x2=63.404,22.320,25.384,P＜0.05).进一步根据UC临床症状进行分层分析,远端UC组和广泛UC组中GSTT1(-)、GSTP1(Val/Val)的分布频率分别为71.6%(164/229)、57.6%(132/229)和31.7%(13/41)、29.3%(12/41),两组比较,差异有统计学意义(x2=24.528,9.609,P＜0.05).远端UC组与广泛UC组的GSTM1(-)基因型的分布频率分别为65.1%(149/229)和56.1%(23/41),两组比较,差异无统计学意义(x2=1.210,P＞0.05).远端UC组和广泛UC组中GSTT1(-)和GSTP1(Val/Val)的分布频率分别为71.6%(164/229)、31.7%(13/41)和57.6%(132/229)、29.3%(12/41),两组比较,差异有统计学意义(x2=24.528,9.609,P＜0.05).轻中度UC组和重度UC组中GSTM1(-)、GSTT1(-)、GSTP1(Val/Val)分布频率比较,差异无统计学意义(x2=0.623,1.884,3.403,P＞0.05).结论 突变的GSTs基因型与湖北汉族人群的UC发生明显相关.GSTs突变基因型可能与UC患者病情严重程度无关.

Abstract：

Objective To investigate the correlation between genetic polymorphisms of glutathione S-transferases (GSTs) and ulcerative colitis (UC) in Hubei Han population. Methods Genetic polymorphisms of GSTM1 and GSTT1 of 270 patients with UC (UC group) who were admitted to the Zhongnan Hospital, People's Hospital of Wuhan University, Tongji Hospital and Union Hospital of Huazhong University of Science and Technology from August 2002 to December 2009 and 623 healthy people ( control group) were detected by restriction fragment length polymorphism-polymerase chain reaction. All UC patients were allocated to distal UC group (n= 229) and extensive UC group (n =41 ) according to the location of the lesions; and all UC patients were also allocated to mild-moderate group (n = 237) and severe group (n = 33 ). The genetic polymorphisms of GSTP1 of these patients and healthy people were detected by polymerase chain reaction. The genotypes of GSTM1, GSTT1 and GSTP1 were also detected. GSTM1 and GSTT1 containing small DNA segments ( 157 bp and 480 bp) were defined as GSTM1 (+) and GSTT1 (+), otherwise, GSTM(-) and GSTT1 (-), respectively. All data were analyzed by chisquare test. Results The frequencies of GSTM1(-), GSTT1(-) and GSTP1 (Val/Val) were 70.7% (191/270),64.8% (175/270) and 48.9% (132/270) in the UC group, and 41.7% (260/623), 47.2% ( 294/623 ) and 34.3% (214/623) in the control group, with a significant difference between the two groups (x2 = 63. 404,22. 320, 25. 384, P ＜0.05 ). The frequencies of GSTT1 (-) and GSTP1 (Val/Val) were 71.6% (164/229) and 57.6% (132/229) in the distal UC group, which were significantly higher than 31.7% (13/41) and 29.3%( 12/41 ) in the extensive UC group ( x2 = 24.528, 9.609, P ＜ 0.05 ). The frequencies of GSTM1 (-) were 65.1%(149/229) in the distal UC group and 56.1% (23/41) in the extensive UC group, with no significant difference between the two groups ( x2 = 1. 210, P ＞ 0.05 ). The frequencies of GSTT1 (-) and GSTP1 ( Val/Val ) were 71.6%(164/229), 31.7% ( 13/41 ) in the distal UC group and 57.6% ( 132/229), 29.3% ( 12/41 ) in the extensive UC group, with a significant difference between the two groups ( x2 = 24. 528, 9. 609, P ＜ 0. 05 ). There was no significant difference in the frequencies of GSTM1 (-), GSTT1 (-), GSTP1 (Val/Val) in the mild-moderate group and the severe group( x2 = 0. 623, 1. 884, 3. 403, P ＞ 0. 05 ). Conclusions Variant genotypes of GSTs are significantly correlated with UC in Hubei Han population. The severity of UC may not be correlated with variant genotypes of GSTs.     

A pharmacokinetic study of piroxicam in children

Feldene Melt (piroxicam) is commonly used for analgesia following day case surgery. The manufacturer's recommended paediatric dose is 0.4 mg.kg(-1) once daily. In children, plasma piroxicam levels of 3-5 microg.ml(-1) are associated with effective analgesia. However, in adults a single dose of 20 mg piroxicam (0.4 mg.kg(-1) for a 50-kg adult) produces plasma levels of only 1.5-2.2 microg.ml(-1). We therefore studied plasma levels achieved by 0.4 mg.kg(-1) or 1.0 mg.kg(-1) piroxicam in 22 children aged between 3 and 16 years, undergoing elective orthopaedic surgery, in order to investigate the adequacy of single dosing. The first 12 patients received 0.4 mg.kg(-1) Feldene Melt pre-operatively. Following assay of plasma piroxicam levels, a further 10 patients received 1.0 mg.kg(-1) Feldene Melt. In both groups, five blood samples were taken at 2-hourly intervals. The mean (95% CI) piroxicam level following 0.4 mg.kg(-1) was 2.90 (2.33-3.54) microg.ml(-1), compared to 5.87 (4.58-7.16) microg.ml(-1) following 1.0 mg.kg(-1) (p = 0.0003).     

Proximal tubule sphingosine kinase-1 has a critical role in A(1) adenosine receptor-mediated renal protection from ischemia

Renal ischemia-reperfusion injury is a major cause of acute kidney injury. We previously found that renal A(1) adenosine receptor (A(1)AR) activation attenuated multiple cell death pathways including necrosis, apoptosis, and inflammation. Here, we tested whether induction of cytoprotective sphingosine kinase (SK)-1 and sphingosine-1-phosphate (S1P) synthesis might be the mechanism of protection. A selective A(1)AR agonist (CCPA) increased the synthesis of S1P and selectively induced SK1 in mouse kidney and HK-2 cells. This agonist failed to protect SK1-knockout but protected SK2-knockout mice against renal ischemia-reperfusion injury indicating a critical role of SK1 in A(1)AR-mediated renal protection. Inhibition of SK prevented A(1)AR-mediated defense against necrosis and apoptosis in HK-2 cells. A selective S1P(1)R antagonist (W146) and global in vivo gene knockdown of S1P(1)Rs with small interfering RNA completely abolished the renal protection provided by CCPA. Mice selectively deficient in renal proximal tubule S1P(1)Rs (S1P(1)R(f)(/)(f) PEPCK(Cre/-)) were not protected against renal ischemia-reperfusion injury by CCPA. Mechanistically, CCPA increased nuclear translocation of hypoxia-inducible factor-1α in HK-2 cells and selective hypoxia-inducible factor-1α inhibition blocked A(1)AR-mediated induction of SK1. Thus, proximal tubule SK1 has a critical role in A(1)AR-mediated protection against renal ischemia-reperfusion injury.