Cellular energetics and glutathione status in NRK-52E cells: toxicological implications

Cellular energetics and redox status were evaluated in NRK-52E cells, a stable cell line derived from rat proximal tubules. To assess toxicological implications of these properties, susceptibility to apoptosis induced by S-(1,2-dichlorovinyl)-L-cysteine (DCVC), a well-known mitochondrial and renal cytotoxicant, was studied. Cells exhibited high activities of several glutathione (GSH)-dependent enzymes, including gamma-glutamylcysteine synthetase, GSH peroxidase, glutathione disulfide reductase, and GSH S-transferase, but very low activities of gamma-glutamyltransferase and alkaline phosphatase, consistent with a low content of brush-border microvilli. Uptake and total cellular accumulation of [14C]alpha-methylglucose was significantly higher when cells were exposed at the basolateral as compared to the brush-border membrane. Similarly, uptake of GSH was nearly 2-fold higher across the basolateral than the brush-border membrane. High activities of (Na(+)+K(+))-ATPase and malic dehydrogenase, but low activities of other mitochondrial enzymes, respiration, and transport of GSH and dicarboxylates into mitochondria were observed. Examination of mitochondrial density by confocal microscopy, using a fluorescent marker (MitoTracker Orange), indicated that NRK-52E cells contain a much lower content of mitochondria than rat renal proximal tubules in vivo. Incubation of cells with DCVC caused time- and concentration-dependent ATP depletion that was largely dependent on transport and bioactivation, as observed in the rat, on induction of apoptosis, and on morphological damage. Comparison with primary cultures of rat and human proximal tubular cells suggests that the NRK-52E cells are modestly less sensitive to DCVC. In most respects, however, NRK-52E cells exhibited functions similar to those of the rat renal proximal tubule in vivo.     

Nephrotoxicity in survivors of Wilms' tumours in the North of England

One aspect of concern for survivors of Wilms' tumour has been the late outcome in terms of renal function. Previous studies have documented low glomerular filtration rate and high blood pressure in some patients. Furthermore, disorders in tubular function (especially urinary concentration defects) have been suggested but not confirmed in small studies. The aim of this study was to determine the prevalence and nature of subclinical and overt glomerular, proximal and distal renal tubular toxicity in a population based cohort of survivors of Wilms' tumour. Forty patients (24 female) with a median age of 4.3 years (3 months-11.8 years) at diagnosis were studied. Median follow-up was 8.8 (range 0.06-27.5) years. Glomerular filtration rate was measured by (51)Cr-EDTA plasma clearance, proximal tubular function by electrolyte fractional excretions, urine excretion of low molecular weight proteins (retinol-binding protein) and renal tubular enzymes (alanine aminopeptidase; N-acetylglucosaminidase) and distal tubular function by the osmolality of the first two urines of the day on 3 consecutive days. Renal size (ultrasound) and blood pressure were also measured. Mean (range) glomerular filtration rate was 100 (61-150) ml min(-1) 1.73 m(-2). Nine were below the reference range for healthy individuals with two kidneys. Most serum electrolyte concentrations (sodium, potassium, chloride, calcium, magnesium and phosphate) fell within the normal range for age, as did the fractional excretions. The values that fell outside the normal range were only marginally abnormal. Subclinical measures of tubular toxicity (retinal-binding protein, alanine aminopeptidase, N-acetylglucosaminidase) were abnormal in only four patients. Thirty-seven patients achieved maximal urine osmolalities > or =800 mOsm kg(-1), but three failed to achieve this value even after DDAVP administration. Two patients had evidence of increased urinary albumin excretion. Compensatory renal hypertrophy was seen in all but two patients, but blood pressure was within normal limits in all patients. Current and past treatment for Wilms' tumour does not have any clinically important nephrotoxic effect in the majority of patients. This finding will enable paediatric oncologists to reassure patients and parents that treatment for Wilms' tumour rarely causes long-term renal impairment.     

Brief report: imitation effects on children with autism

Twenty children with autism (mean age, 5 years) were recruited for the study from a school for children with autism. The children were randomly assigned to an imitation (n = 10) or contingently responsive (n = 10) interaction group based on a stratification table for gender and developmental and chronological age. The sessions consisted of four phases, with each phase lasting 3 minutes. In the first phase, the child walked into a room that was furnished with a sofa, a table, chairs, and two sets of identical toys. An adult was in the room sitting very still like a statue (first still-face condition). In the second phase, the adult either imitated the child or was contingently responsive to the child. In the third phase, the adult sat still again (second still-face condition), and in the fourth phase, the adult engaged in a spontaneous interaction. During the third phase (the second still-face condition), the children in the imitation group spent less time in gross motor activity and more time touching the adult, as if attempting to initiate an interaction. The contingency condition appeared to be a more effective way to facilitate a distal social behavior (attention), whereas the imitative condition was a more effective way to facilitate a proximal social behavior (touching).     

Proneural,prosensory, antiglial: the many faces of neurogenins

Previous reports have linked Neurogenin 1 with the general promotion of neurogenesis and gliogenesis. A new study in zebrafish, supported by recent findings in Drosophila, has now challenged this idea by demonstrating that the activity of Neurogenin 1 is limited to activation of development of two classes of sensory neurons.     

Prevention of diabetes-induced albuminuria in transgenic rats overexpressing human aldose reductase

Studies using pharmacologic inhibitors have implicated the enzyme aldose reductase in the pathogenesis of albuminuria and diabetic renal disease. However, a clear conclusion is not easily drawn from such studies since these pharmacologic inhibitors have nonspecific properties. To examine further the role of aldose reductase, we have overexpressed the human enzyme in a transgenic rat model. Transgene expression in the kidney was predominantly localized to the outer stripe of the outer medulla, compatible with the histotopography of the straight (S3) proximal tubule. The effect of enzyme overexpression on diabetes-induced renal function and structure was then investigated. Contrary to what may have been anticipated from the previous enzyme inhibition studies, diabetes-induced albuminuria was completely prevented by the overexpression of aldose reductase. No effect of overexpression of aldose reductase on renal structure nor on urinary excretion of β₂-microglobulin and N-acetyl-β-d-glucosaminidase was observed in this transgenic rat model. In conclusion, our study strongly suggests that multiple roles for aldose reductase may give it a more complex place in diabetic nephropathy than is currently recognized.     

模拟失重对新西兰兔股静脉压力-容积关系的影响

目的观察模拟失重对兔股静脉压力 -容积关系的影响及静脉壁显微结构的变化。方法采用头低位 ( - 2 0°)倾斜的方法作为模拟失重家兔模型。 2 4只雄性健康新西兰兔 ,随机分为对照组、模拟失重 2 1d组和模拟失重 1 0d组 ,每组 8只。进行股静脉的压力 -容积 (P V)关系测试 ,并观察血管壁的显微结构。结果模拟失重后股静脉P V曲线向容积变化比增大的方向移动 ,模拟失重 2 1d组较 1 0d组移动更明显。分别于加、卸载测试时拟合出的模拟失重 2 1d组P V二次抛物线方程式系数B1 、B2 值均显著高于对照组及模拟失重 1 0d组 (P <0 .0 1 ) ,模拟失重 1 0d组的B1、B2值和对照组相比有增加的趋势。组织学观察表明 ,模拟失重组股静脉内皮细胞呈立方或矮柱状并有细胞脱落 ,平滑肌层变薄等变化。结论模拟失重后股静脉顺应性增加 ,2 1d组较 1 0d组增加明显 ,同时股静脉管壁结构也发生明显改变     

Proximal femoral osteotomy for the treatment of hip arthritis in young adults

Background : The outcome of proximal femoral osteotomy for hip arthritis in young adults performed at the Wellington Hospital (Wellington, New Zealand) was reviewed. Methods : Seventeen patients underwent 21 proximal femoral osteotomies for the treatment of hip arthritis at Wellington Hospital between 1992 and 1999. Thirteen patients (17 hips) were contacted and were able to complete a questionnaire form specific for hip pain and function. Results : There was a response rate of 76.5% (13 out of a possible 17 patients undergoing proximal femoral osteotomy) at a mean 3 years 4 months postoperatively. Of these, one patient has had a total hip joint replacement and one patient is currently on the waiting list for a total hip joint replacement. Three other patients (three hips) report moderate or severe hip pain. The remaining eight patients (12 hips) report having mild or no hip pain. Questionnaire results show a postoperative decrease in hip pain in most patients. Hip function as assessed by the questionnaire was essentially unchanged. Conclusions : Proximal femoral osteotomy is a satisfactory option for young patients with degenerative hip arthritis. The operation is only likely to be useful in the treatment of pain.     

Comparison of effects of anandamide at recombinant and endogenous rat vanilloid receptors

Background. Anandamide, an endogenous lipid, activates bothcannabinoid (CB₁) and vanilloid (VR1) receptors, both of whichare co-expressed in rat dorsal root ganglion (DRG) cells. Activationof either receptor results in analgesia but the relative contributionof CB₁ and VR1 in anandamide-induced analgesia remains controversial.Here we compare the in vitro pharmacology of recombinant andendogenous VR1 receptors using calcium imaging, in clonal andDRG cells, respectively. We also consider the contribution ofCB₁ and VR1 receptors to anandamide-induced analgesia. Methods. Using a Flurometric Imaging Plate Reader (FLIPR^TM),calcium imaging has been used to study the effects of severalvanilloid and cannabinoid ligands in rat VR1-transfected HEK293(rVR1-HEK) cells and in DRG cells. The effect of pre-exposureof several vanilloid and cannabinoids has also been comparedin DRG cells. Results. The VR1 agonists capsaicin, olvanil, (N-(4-hydroxyphenyl-arachinoylamide)(AM404) and anandamide caused a concentration-dependent increasein intracellular calcium concentration ([Ca²⁺]_i), with similartemporal profiles in both rVR1-HEK and DRG cells, and potency(pEC₅₀) values of 8.25 (SEM 0.11), 8.37 (0.04), 6.96 (0.06),5.85 (0.01) and 7.45 (0.10), 7.55 (0.07), 6.10 (0.13), approximately5.5, respectively. These responses were inhibited by the VR1antagonist capsazepine (1 µM). In contrast, applicationof synthetic cannabinoid antagonists failed to inhibit the anandamide-inducedincrease in [Ca²⁺]_i. Reapplication of VR1 agonists significantlyinhibited a subsequent challenge to either capsaicin or anandamidein either cell type, whilst pre-exposure to cannabinoid agonistswere without effect. Conclusion. Here we provide evidence that the pharmacology ofrecombinant rVR1 receptors is similar to those endogenouslyexpressed in DRG cells. Moreover, we have shown that VR1, butnot CB₁, receptors are involved in anandamide-induced responsesin dorsal root primary neurones in vitro. Therefore, the analgesicproperties of anandamide are likely to be mediated, at leastin part, by VR1 activation in DRG cells in vivo. Br J Anaesth 2002; 89: 882–7     

内固定与髋关节置换术治疗老年有移位股骨颈骨折的系统评价

目的：比较骨折复位内固定与髋关节置换术治疗老年股骨颈骨折的疗效。方法：收集所有的内固定与髋关节置换术治疗老年股骨颈骨折的随机对照试验（RCT），对其逐个进行质量分析，作系统评价。结果：内固定术较髋关节置换术手术时间短（P〈0．05），手术失血量少（P〈0．05），术后并发症少（P〈0．05），但其再次手术率明显高于髋关节置换术（P〈0．05）。结论：内固定术的创伤较小，术后并发症少，但因其术后骨折不愈合和股骨头缺血坏死率较高，其再次手术率明显高于髋关节置换术。     

支持钢板内固定治疗复杂胫骨平台骨折

目的探讨应用支持钢板内固定术在复杂性胫骨平台骨折的手术方法及疗效。方法回顾1997年1月～2005年1月收治按Schatzker分类的复杂性胫骨平台骨折:Ⅳ型20例,Ⅴ型14例,Ⅵ型11例。经切开复位,支持钢板内固定治疗。结果根据Hohl膝关节功能评分方法进行综合评分:优26例,良11例,可4例,差4例。结论复杂性胫骨平台骨折应考虑手术治疗,以支持钢板为宜,X线、CT、MRI检查相结合对骨折的全面评价及指导手术有重要意义,必须早期处理受损的软组织。