内皮源性舒张因子在甘油致大鼠急性肾功能衰竭中的作用

为探讨内皮源性舒血管因子（ｅｎｄｏｔｈｅｌｉｕｍ－ｄｅｒｉｖｅｄｒｅｌａｘｉｎｇｆａｃｔｏｒ，ＥＤＲＦ）在急性肾功能衰竭（ＡＲＦ）发生发展中的作用及其机制，在甘油致大鼠ＡＲＦ模型上，分别观察了ＮＯ前体Ｌ－ａｒｇｉｎｉｎｅ（Ｌ－Ａｒｇ）和ＮＯ合成酶抑制剂Ｎ－ｎｉｔｒｏ－Ｌ－ａｒｇｉｎｉｎｅ（Ｌ－ＮＮＡ）的作用。实验结果表明：ＡＲＦ大鼠ＮＯ合成减少，Ｌ－Ａｒｇ能明显降低ＡＲＦ大鼠血清中的ＢＵＮ和Ｓｃｒ，尿中ＮＡＧ和肾皮质中的钙含量，而提高血清ＮＯ水平，增加肾组织ｃＧＭＰ含量，改善肾功能；Ｌ－ＮＮＡ则使ＡＲＦ恶化。提示：ＥＤＲＦ在甘油所致ＡＲＦ大鼠的发生发展中可能起重要的保护作用。     

急性肾功能衰竭专家诊断系统

根据目前在急性肾功能衰竭诊断中存在的误诊和漏诊问题，我们开发了急性肾功能衰竭专家诊断系统，旨在帮助基层医院早期正确诊断急性肾功能衰竭。这是一个基于规则的专家系统，其推理控制结构和专家系统知识相互独立，采用深度优先反向链推理机制，能处理不确定知识，在可信度处理方法和ＩＦ…ＴＨＥＮ…规则类型方面较既往的基于规则的专家系统有了改进，经过验证，该系统达到了我科肾脏病专家的诊断水平     

丹参酮ⅡA对急性肾功能衰竭大鼠肾脏的保护作用

目的探讨丹参酮ⅡA对急性肾功能衰竭(AFR)大鼠肾小管上皮细胞及肾功能的作用。方法将64只大鼠分为4组:对照组、模型组、丹参酮低剂量组和丹参酮高剂量组,每组又分为48 h组和72 h组两个亚组。应用肌肉内注射甘油制备大鼠AFR模型。然后腹腔内注射不同浓度的丹参酮ⅡA进行干预。然后在48 h和72 h检测血尿素氮(BUN)、肌酐(Scr)和24 h尿蛋白定量;同时制作组织切片,观察肾组织结构改变,并应用免疫组织化学方法检测肾组织Ki-67的表达。结果丹参酮高剂量72 h组的各项病理损害指标均低于其他各组(P<0.05);丹参酮高剂量48 h及72 h组的Ki-67阳性细胞计数明显高于其他各组(P<0.05)。结论丹参酮ⅡA对急性损伤的肾小管上皮细胞具有减轻病变和促进再生的作用,可明显改善ARF大鼠的肾功能。     

血管活性物质与急性肾功能衰竭

急性肾功能衰竭时 ,血管活性物质异常释放可引起肾血流量的异常。本文对肾素、血管紧张素Ⅱ、内皮素、一氧化氮、心房肽、精氨酸加压素等血管活性物质在急性肾功能衰竭中的作用作一综述。     

胰岛素样生长因子与急性肾功能衰竭

胰岛素样生长因子－１（ＩＧＦ—Ⅰ）是研究较早的多肽生长因子之一，它由肝脏、肾系膜细胞等分泌。在后肾的发生及急性肾损伤再生修复中起着重要的调节作用。１ＩＧＦＳ的早期研究实践中发现，一侧肾切除后即单切，留存肾会出现代偿性生长。动物实验证明，肾部分切除后１...     

老年急性肾功能衰竭的特点

目的：老年急性肾功能衰竭（Acute renal failure,ARF）随着老年化的进程而逐年上升,且病情复杂,并发症多见,预后险恶。由于老年肾脏结构功能的退行性变及其机体整体功能的下降,致使老年急性肾功能衰竭有其自身的特点,现就此作一综述。     

维拉帕米对缺血性急性肾功能衰竭的保护作用

目的：观察维拉帕米对缺血性急性肾功能衰竭是否具有保护作用。方法：以维拉帕米灌注切除右肾的成年雄性ＳＤ大鼠之左肾，５ｍｉｎ后夹闭左肾动脉４５ｍｉｎ，对照组则灌注生理盐水。再灌注２４ｈ后，观察左肾血流量（ＬＲＢＦ），尿量（ＵＶ），血尿素氮（ＢＵＮ），血肌酐，肌酐清除率（ＣＣｒ），左／右肾重量之比，肾脏组织学评分ＨＳＫ，尿中Ｎ＿乙酰氨基葡萄糖苷酶（ＮＡＧ）和丙氨酸氨基肽酶（ＡＡＰ）活性的变化。结果：与对     

急性肾功能衰竭发病机理的研究进展

本文综述急性肾功能衰竭中肾小管能量耗竭、ca~(2+)蓄积、自由基、磷脂酶和细胞因子等对肾上管细胞的损伤作用,肾小管细胞脱落和再粘附的机理,以及内皮素、一氧化氮等介质和内皮细胞功能改变所致的继发性肾小球血液动力学变化等方面的研究进展,并探讨肾小管细胞修复和肾小球滤过功能恢复的可能机理。     

抗痨药物致急性肾功能衰竭临床观察分析

目的 通过分析抗痨药物致急性肾功能衰竭的原因及其临床特点,探讨早期预防及治疗措施.方法 对我院2003~2010年确诊的抗痨药物致急性肾功能衰竭40例进行回顾性分析.结果 40例患者中治愈好转31例,中途放弃治疗自动出院8例,死亡1例.其中早期行血液透析的患者预后良好.结论 抗痨药物致急性肾功能衰竭除与患者年龄、原有的基础病有关外,最重要的与抗痨药物的使用关系更密切.一旦确诊,应立即停服抗痨药物,并早期行血液透析治疗,可提高治愈好转率.     

樟柳碱、东莨菪碱、山莨菪碱对急性肾功能衰竭大鼠的治疗作用

本文采用直接从左肾动脉注射油酸的方法制备大鼠急性肾功能衰竭(ARF)模型,从改善微循环的角度寻求ARF的防治措施。结果表明,樟柳碱、东莨菪碱、山莨菪碱均可不同程度减轻肾内微血管损伤及肾组织水肿,改善肾内脉动血管的功能,提高肾组织血液灌流量,提高血液中前列环素(PGI_2)的浓度,减轻肾组织缺血及肾小管损伤。樟柳碱的效果优于东莨菪碱及山莨菪碱。这些结果证明,莨菪类药对油酸致大鼠ARF有治疗作用。     

Erythropoietin in thrombotic thrombocytopenic purpura and acute renal failure

Summary In this study, erythropoietin serum levels were serially determined in eight patients with acute renal failure to get a lead on the etiology of anemia in acute renal failure and to address the relationship between erythropoietin synthesis and renal excretory performance. Erythropoietin serum levels rapidly decreased after onset of acute renal failure to values of 12.8 ± 10.3 mU/ml compared to 16.8 ± 9.4 mU/ml in healthy controls. After restoration of renal function, erythropoietin levels climbed slowly in six patients (15.2 ±5.3 mU/ml), and in relation to prolonged anemia in these patients, a relative deficiency of erythropoietin could be observed. In one patient with thrombotic thrombocytopenic purpura causing acute renal failure, the decline of erythropoietin secretion was not observed, and in a phase of the disease when plasma exchange therapy was interrupted, markedly increased erythropoietin levels, up to 182 mU/ml, were detected despite the renal failure. Focusing on erythropoietin secretion in thrombotic thrombocytopenic purpura, we followed hormone synthesis in two other patients with the same disease, one of whom had mild renal insufficiency and one had normal renal function. High erythropoietin levels of up to 205 mU/ml were found in these patients, similar to the peak levels found in the patient with complete renal failure. Plasmapheresis treatment reduced erythropoietin production in all three patients with thrombotic thrombocytopenic purpura. In summary, our study indicates that in most cases of acute renal failure, erythropoietin synthesis is compromised and may contribute to the development of anemia in renal failure and aggravate the persistence of anemia after restoration of renal function. Comparing erythropoietin production in patients with acute renal failure and in those with thrombotic thrombocytopenic purpura with varying renal involvement we conclude that erythropoietin secretion is not closely linked to renal excetory performance, and that hemolysis or other stimuli in thrombotic thrombocytopenic purpura can override the decline of erythropoietin production implied by renal failure.Abbreviations ARF acute renal failure - EPO erythropoietin - TTP thrombotic thrombocytopenic purpura     

The early phase of experimental acute renal failure

Experiments were performed to determine whether furosemide, given in doses high enough to induce a strong diuresis and to inhibit the mechanism of tubuloglomerular feedback, offers any protection from acute renal failure induced by a nephrotoxin or ischaemia. Microperfusion of the loop of Henle revealed that a tubular furosemide concentration of 5·10^–5 mol·l^–1 was necessary to fully inhibit the tubuloglomerular feedback response to a raised sodium chloride concentration at the macula densa. The infusion of furosemide systemically to achieve such concentrations in the tubule resulted in an improvement in renal function when given before or after the nephrotoxin but was without effect when given before or after ischaemia. Measurements of furosemide concentrations in the urine, however, confirmed that sufficient amounts were applied to inhibit the feedback mechanism. It is concluded from this and similar studies that furosemide is only beneficial in models of acute renal failure with an obstructive or nephrotoxic pathogenesis, in which it acts by flushing out the noxious material and not by inhibiting the mechanism of tubuloglomerular feedback.     

The early phase of experimental acute renal failure

Experiments were conducted to determine whether suppression of the renin-angiotensin-system and inhibition of the tubuloglomerular feedback response offer protection from acute renal failure, as found in chronically-salt loaded animals. The juxtaglomerular renin activity and tubuloglomerular feedback response were inhibited acutely, by saline expansion, or chronically by DOCA-treatment with saline drinking fluid or salt diet, by high salt diet alone, or by inducing two-kidney Goldblatt hypertension. The chronic pretreatment procedures depressed juxtaglomerular renin to 16, 7, 13 and 4% of control, respectively, inhibited the feedback response to 53, 37, 56, and 38% of control, respectively, but conferred no benefit in the first hours following a nephrotoxin or ischaemia. In contrast, the acute treatment procedure reduced juxtaglomerular renin activity to only 56% and lowered the feedback response to only 71%, but improved renal function after the nephrotoxin, although not after ischaemia. It is concluded that since severe restrictions of renin activity and tubuloglomerular feedback are not protective, neither is primarily involved in generating the functional restrictions early in acute renal failure. The restoration of renal function by saline expansion accompanied only a modest depression of these two systems and suggests that the beneficial effect may result more from volume expansion or diuresis than from suppression of renal renin or inhibition of tubuloglomerular feedback.     

The early phase of experimental acute renal failure

Experiments were conducted to establish whether diminished solute reabsorption in the loop of Henle during acute renal failure could explain the loss of urinary concentration and participate in generating a tubuloglomerular feedback-mediated reduction in filtration rate. The electrolyte content of the fluid in the ascending limb of the loop of Henle was determined in situ by monitoring its electrical conductivity after propulsion into the distal tubule with a sudden burst perfusion. The value of the minimum electrolyte concentration decreased exponentially with increasing equilibration time, reaching a steady-state value equivalent to 27±9 mM NaCl in normal kidneys, 34±15 mM in mercuric chloride kidneys and 53±22 mM following ischaemia. A mathematical model was derived to describe the process of sodium chloride dilution from which it was possible to calculate both the permeability and transport velocity of the cortical thick ascending limb. In the normal kidney, the transport velocity was calculated to be 4.65±0.92 ·10^–5 cm/s, a value not significantly different from that of the mercuric chloride or ischaemic kidneys, and the estimated permeability was 1.13±0.52·10^–5 cm/s, not different from that of the mercuric chloride kidneys but significantly lower than that calculated for the ischaemic kidneys. It is concluded that for the more severely damaged ischaemic model, the loss of urinary concentrating ability was accompanied by a reduction in diluting ability of the ascending limb of the short loop of Henle, which appears to be due, at least in part, to an elevation of the passive permeability to sodium chloride in this segment.     

Tubular ultrastructure in acute renal failure in man: Epithelial necrosis and regeneration

Summary It is not clear whether tubular cell necrosis is present or not in acute renal failure (ARF) of ischaemic type (acute tubular necrosis). In order to get quantitative data, using precisely defined criteria for tubular cell necrosis, 25 renal biopsies from 24 patients with ARF (11 obtained in the active phase, 14 in the early recovery period) were compared with 12 control biopsies. In all 1959 proximal cells and 1603 distal cells were analysed by electron microscopy. Cellular disintegration was very rare in all groups. Shrinkage necrosis (apoptosis) was not present in the proximal tubules of the controls and was rare in ARF (1.6–2.1%). In the distal tubules of controls 2.7% of all cells showed shrinkage necrosis. The incidence in ARF was not significantly increased. Non-replacement sites in distal tubules (probablyloci where cells have recently been desquamated) were significantly increased in number (5.2%) in the active phase in ARF compared to controls and recovery. The relative number of regenerating cells was not increased.These data show that there is no widespread necrosis of tubular cells in ARF. The increased incidence in distal tubules of focal, denuded areas of the basement membrane in the active phase of ARF indicates a slightly increased desquamation of cells and/or a failure to cover such sites by adjacent cells. This process is not restricted to the brief induction phase of ARF but continues during the whole active phase.     

Temporary changes in macrophages and MHC class-II molecule-expressing cells in the tubulointerstitium in response to uranyl acetate-induced acute renal failure in rats

The present study was designed to asses the dynamic changes in macrophages (Møs) with or without expression of major histocompatibility complex (MHC) class-II molecule in response to uranyl acetate-induced acute renal failure (ARF) in rats. ED1+ monocytes/Møs infiltrated into the interstitium as early as day 2, peaked in number on day 5 after uranyl acetate-induced ARF. ED1+ cells did not correlate with necrotic tubules but accumulated abundantly in the vicinity of the Ki67+ regenerating proximal tubules around days 4–5. Afterward, regeneration of proximal tubules was accelerated. After day 5, some ED1+ cells entered the tubular lumen, and became ED1+ giant cells, which had features of phagocytic Møs by immunoelectron microscopy, peaking in number on day 7. Most ED1+ cells did not incorporate [³H]-thymidine, indicating lack of active proliferation. The number of OX6+ cells (directed to MHC class-II molecule) in the interstitium significantly increased on day 4 and peaked on day 5. Double staining revealed that ED1+OX6– cells entered the tubular lumen while ED1+OX6+ cells remained in the peritubular regions. Osteopontin (OPN) protein and mRNA were significantly upregulated. No specific relationship could be found between OPN+ regenerating proximal tubules and ED1+ cells, but most ED1+ giant cells were OPN+ and intermingled among OPN+ cell debris. Our findings suggest that ED1+ Møs are actively associated with regenerating proximal tubules and, thus, might promote proximal tubular regeneration. ED1+OX6– Møs may function as scavengers and phagocytose cellular debris in the tubular lumen, cleaning the wound site. OPN might be involved in this process. ED1+OX6+ Møs in the peritubular regions may act as outpost of the defense system to monitor incoming antigens. Our data indicate that Møs with or without expressing MHC class-II molecule contribute to the defense and repair of injured proximal tubules in this ARF.     

The early phase of experimental acute renal failure

Summary Experiments were designed to determine whether leakage of substances across the tubular epithelium, which are impermeant in the normal kidney, falsifies the measurement of glomerular filtration rate in acute renal failure. Permeability to those substances most commonly used for filtration rate determination, polyfructosan, inulin and ferrocyanide, was estimated by measuring their recoveries following perfusion through various nephron segments in haeme pigment, ischaemic and nephrotoxic models of actue renal failure. Late proximal recovery of¹⁴C ferrocyanide was only marginally decreased compared to controls, by a maximum of 6%. Distal recovery of polyfructosan,¹⁴C and³H inulin were depressed somewhat more, by a maximum of 11%. Urinary recovery of¹⁴C inulin was reduced by only 15% in kidneys showing severely restricted renal function. It is concluded that tubular leakage is not a feature of significance in the early phase of moderate acute renal failure, that ferrocyanide and inulin are reliable markers for the determination of nephron filtration rate and water reabsorption, and that the reduction in whole kidney inulin or polyfructosan clearance reflects primarily a reduction in glomerular filtration rate.     

The early phase of experimental acute renal failure

Summary Tubular obstruction in acute renal failure, postulated to cause the restricted excretory function, is suggested by raising intratubular pressure, to lower effective filtration pressure and diminish urine output. To examine the applicability of the obstruction hypothesis to the pathogenesis of experimental acute renal failure, proximal intratubular pressure and renal function were measured after renal insults of different origins and severity. Obstruction in acute renal failure kidneys should manifest itself as an increase in intratubular pressure for a least 12 h, for within this time period following ureteral occlusion, elevated pressures were found to reflect obstruction. The consistent existence of raised proximal intratubular pressure in acute renal failure kidneys could not be detected; ischaemic and nephrotoxic models were found in which no rise in intratubular pressure could be demonstrated. The oliguric nature of acute renal failure kidneys could not be verified; ischaemic and nephrotoxic models were found in which urine output was either normal or enhanced. Only for methaemoglobin induced renal failure were raised intratubular pressure, oliguria and casts concurrent. It is concluded that obstruction is not a consistent feature of experimental acute renal failure and that the obstruction hypothesis may be specifically applicable to only a few models, which include haeme pigment and folic acid induced renal failure.     

Plasma protein extravasation and vascular endothelial growth factor expression with endothelial nitric oxide synthase induction in gentamicin-induced acute renal failure in rats

Microvascular hyperpermeability to plasma proteins via vascular endothelial growth factor (VEGF) with endothelial nitric oxide synthase (eNOS) induction may contribute to wound healing through matrix remodeling. However, vascular hyperpermeability is not examined in acute renal failure (ARF), a unique form of wound healing. Subcutaneous injection of gentamicin (400 mg/kg per day for 2 days in divided doses every 8 h) in rats increased serum creatinine levels and induced tubular damage, which peaked at day 6, after the last gentamicin injection. Ki67-positive regenerating proximal tubules (PTs) peaked in number at day 6 and almost covered the bare tubular basement membrane (TBM) by day 10. Staining of fibrinogen and plasma fibronectin began to increase in the peritubular regions as early as day 0, steadily increased in TBM and tubular lumen until day 6 and then decreased. Hyperpermeable peritubular capillaries were identified by extravasation of perfused-fluoresceinated dextran (both 70 kDa and 250 kDa) into peritubular regions as early as day 0 and prominently into TBM and tubular lumen at day 6. Electron microscopy further suggested the intraendothelial pathway of dextran. Immunoreactive VEGF increased in the damaged and regenerating PTs. Immunoreactive VEGF receptors-1 and -2 did not change, but immunoreactive eNOS increased in the peritubular capillaries after induction of ARF. Western blotting for VEGF and eNOS supported the immunostaining findings. In addition, we assessed the effects of NOS inhibitor N-nitro-l-arginine methyl ester (l-NAME) on vascular hyperpermeability during the recovery phase of this model. Treatment with l-NAME (s.c. at a dose of 100 mg/kg/day from day 3 to day 6) decreased extravasation of perfused-250-kDa dextran and significantly inhibited the regenerative repair of PTs at day 6 when compared with vehicle-treated rats. In conclusion, plasma protein extravasation occurred, leading to matrix remodeling, such as the process of wound healing during the tubular repair in gentamicin-induced ARF. Since VEGF-induced vascular hyperpermeability may depend on NO production, VEGF/VEGF receptor system with eNOS induction might be responsible for this process.     

Distal tubule [Na+] and juxtaglomerular apparatus renin activity in uranyl nitrate induced acute renal failure in the rat

Summary It has been previously demonstrated that single nephron filtration rate, whole kidney glomerular filtration rate and total renal blood flow decreased by 30–35% 6 h after uranyl nitrate induced acute renal failure in the rat. In order to evaluate a role of the renin-angiotensin system in the initiating phase (0–6 h) of this model of acute renal failure, determinations of plasma renin activity, superficial (S) and deep (D) juxtaglomerular apparatus (JGA) renin activity and distal nephron [Na⁺] were obtained. Plasma renin activity increased from the control value of 1.5±0.3 (S.E.M.) to 2.9±0.4 ng/ml/h (P<0.005) at 6 h. Mean renin activity in S- and D-JGA's of control rats was 6.99±0.41 and 2.67±0.21 ng/JGA/h, respectively. After uranyl nitrate, renin activity in S-JGA's increased to 13.62±0.80 ng/JGA/h (P<0.001) at 2 h and remained elevated, 12.56±0.90 and 12.75±0.87 ng/JGA/h at 4 and 6 h. D-JGA renin activity increased (P<0.05) to 7.04±0.53, 6.23±0.31 and 3.44±0.33 ng/JGA/h at 2, 4 and 6 h after uranyl nitrate. Distal tubule [Na⁺], 27 samples in 6 rats, increased from a mean control value of 53.7±1.2 mEq/l to 116.9±2.5 mEq/1, 24 samples in 6 rats (P<0.001).Prompt increases in JGA renin activity were observed in the initiating phase of acute renal failure, suggesting a role for the renin-angiotensin system in the pathophysiology of this nephrotoxic model. The association of increased JGA renin activity and increased distal [Na⁺] is consistent with a role for the tubuloglomerular feedback mechanism in the initiating phase of uranyl nitrate induced acute renal failure in the rat.