Role of colour Doppler imaging in detecting prostate cancer

OBJECTIVE: This prospective study was undertaken to evaluate the role of colour Doppler sonography in the assessment of prostate carcinoma. METHODS: Forty consecutive patients who were suspected of having prostate carcinoma with either raised prostate specific antigen or abnormal digital rectal examination were included in the study. Transrectal greyscale and colour Doppler sonography of the prostate was performed using a 5-9 MHz intracavitary probe. Needle biopsies were taken from areas that showed increased flow on colour Doppler. The results were correlated with the final diagnosis established on histopathological examination. RESULTS: Comparison of greyscale and colour Doppler sonography showed that the latter is more sensitive and specific in predicting the malignancy. The statistical parameters of colour Doppler versus grayscale sonography were: sensitivity 88.23 vs. 73.52, specificity 66.66 vs. 33.33, positive predictive value 93.75 vs. 85.18, and negative predictive value 50 vs. 22.22, respectively. CONCLUSION: Colour Doppler and greyscale sonography should be routinely performed to improve detection of prostate carcinoma and to target the lesion.     

Intraoperative sonography of renal tumors.

Intraoperative sonography (7.5 MHz. transducer with Doppler probe) was used to evaluate renal masses in 41 kidneys to determine its correlation with pathological findings. This intraoperative determination of the extent of the renal lesion prompted occasional changes in surgical management. We conclude that intraoperative sonography is most useful in partial nephrectomy, and helps to determine the extent of tumor, multicentricity, venous extension and associated cysts. These findings may not be appreciated with intraoperative, visual inspection of the kidney.     

Ultrasonographic fata morgana.

Case A 35-year-old female with end-stage renal disease due to chronicglomerulonephritis received a cadaveric renal transplantationinto the right fossa iliaca. Her body mass index was 23 kg/m².The clinical course after transplantation was uneventful andgraft function was stable during follow-up. Ultrasonographicmonitoring of the renal transplant was performed regularly withB-scan, colour Duplex and Doppler ultrasonography using a 3.75MHz curved array transducer and sector transducer (SonolayerSSA 270A; Toshiba, Tokyo,     

Transport of oxalate across the rabbit papillary surface epithelium

PURPOSE: The renal papilla and pelvic recesses of the mammalian kidney are thought to be the anatomical sites of initial kidney stone formation. We studied oxalate transport across the renal papillary surface epithelium. MATERIALS AND METHODS: In vitro oxalate transport across the papillary surface epithelium was studied by dissecting it off of the papilla and mounting it in a modified Ussing chamber. Experiments were conducted using physiological Ringer's solution at 37C. Removal or appearance of radioactive oxalate from the solution bathing the apical papillary surface epithelium surface was used as a measure of transepithelial transport. RESULTS: When only the papillary surface epithelium apical surface was exposed to oxalate (17 micromol./l.), the apical to basolateral flux of oxalate was 7.1 +/- 1.5 nmol./cm.2 per hour. When only the basolateral side was perfused with oxalate, the basolateral to apical oxalate flux was 1.6 +/- 0.7 nmol./cm.2 per hour. When the apical and basolateral surfaces were exposed to oxalate, a net apical to basolateral flux of oxalate was 3.0 +/- 0.7 nmol./cm.2 per hour. There was almost complete inhibition of apical to basolateral oxalate transport when the experiments were conducted at 20C. Absorption of oxalate across the papillary surface epithelium was decreased by the addition of 1 mM. 4, 4'-diisothiocyanatsostilbene-2,2'-disulphonic acid (DIDS), independent of sodium, but reduced by the presence of chloride in the apical solution. Increasing the pH of the apical solution from 7. 4 to 7.8 also resulted in a significant decrease in papillary surface epithelium oxalate uptake. CONCLUSIONS: Rabbit papillary surface epithelium demonstrates oxalate absorption by mechanisms that may be similar to those described previously for renal and colonic epithelia. Absorption of oxalate across the papillary surface epithelium may have a role in the prevention of initial calcium oxalate stone formation within the pelvic recesses.     

Vitamin E therapy prevents hyperoxaluria-induced calcium oxalate crystal deposition in the kidney by improving renal tissue antioxidant status

OBJECTIVE: To determine whether vitamin E prevents hyperoxaluria-induced stone formation, using a new animal model of calcium oxalate stone disease, as our previous in- vitro and in-vivo studies showed that oxalate and hyperoxaluria induce free-radical generation, which results in peroxidative injury to renal tubular cells. MATERIALS AND METHODS: Ethylene glycol (EG) was administered at 150 mg/day by gavage for 3 weeks to rats fed on diets with adequate (group 1), excess (group 2) or deficient (group 3) vitamin E. Several indicators of peroxidation, free radicals and enzymatic activity were then assessed. RESULTS: EG treatment in group 1 lead to increased lipid peroxidation, protein thiol, excretion of urinary enzymes, oxalate and decreases in urinary calcium, antioxidant enzymes and altered glutathione redox balance. Although renal function was not altered, there was increased water intake, urine volume and lowered urinary pH in these rats. These changes were more intense, with extensive calcium-oxalate crystal deposition, in rats in group 3, and prevented in rats in group 2, except for urinary oxalate levels, which remained high. Histopathological examination showed that there was no deposition of calcium oxalate crystals in rats in group 2. CONCLUSION: This is the first study to demonstrate in-vivo evidence that hyperoxaluria-induced peroxidative injury induces individual calcium oxalate crystal attachment in the renal tubules. In addition, excess vitamin E completely prevented calcium oxalate deposition, by preventing peroxidative injury and restoring renal tissue antioxidants and glutathione redox balance. Therefore, vitamin E therapy might provide protection against the deposition of calcium oxalate stones in the kidney of humans.     

Doppler sonography and B-mode ultrasound scanning in renal stone surgery

Doppler sonography and B-mode ultrasound scanning have been used to perform nephrotomies without circular arrest of the kidney in 107 renal lithotomies. Between 1 and 12 nephrotomies were performed on a single kidney. Average duration of the operation was 270 minutes. The blood loss varied between 20 and 4,500 ml. Three patients required a short period of pedicle clamping. The residual stone rate was 7.5 per cent. Of 9 complications 2 are attributable to the surgical technique. Late follow-up studies in 14 patients showed a 10 per cent improvement of kidney function.     

Evaluation of renal transplant dysfunction by duplex Doppler sonography: a prospective study and review of the literature

A disconcertingly wide variation exists in the literature as to the accuracy of duplex Doppler sonography in the detection of acute renal transplant rejection. Sensitivities range from 9% to 76%. In an attempt to explain the disparity of results, we undertook a double-blind prospective study of the accuracy of duplex Doppler ultrasound in the detection of acute rejection in renal transplants. We scanned 49 consecutive patients with a total of 65 biopsies; 46 biopsies in 33 consecutive patients were included in our study. In our population, the prevalence of acute rejection was 61% (28/46). Using a resistive index (RI) cutoff of greater than 0.90 based on the main renal artery flow pattern, the sensitivity of our test was 43%, with a 67% specificity. The positive predictive value was 67%. Our results are contrasted and compared with the published data from other groups in a critical survey of the literature. We conclude that duplex Doppler sonography alone is inadequate to evaluate acute rejection in renal transplants.     

Surgical aspects of urolithiasis in children

Operative management of renal calculi has changed radically in the last decade. New operative techniques. the use of intra-operative ultrasound and Doppler sonography have even made possible the removal of complete staghorn calculi in short and kidney-preserving procedures. The introduction of percutaneous nephrolithotomy and stone extraction using a specially designed ureteroscope and, above all, the clinical application of extracorporeal shock wave lithotripsy have made stone surgery less invasive and have provided a higher rate of preservation of kidney function.     

草酸钙结石患者肾乳头Randall斑的超微结构特点

目的 探讨草酸钙结石患者肾乳头Randall斑与草酸钙结石形成的关系. 方法经结石化学成分分析确诊为草酸钙肾结石患者12例.于经皮肾镜取石术中直视卜获取肾乳头Randall斑活检标本,分别行HE染色和锇酸固定,光镜和透射电镜下观察其组织病理和超微结构特点.结果 12例患者共检查肾乳头72处,肾乳头表面有Randall斑形成63处(87.5%),7例部分肾乳头表面有小结石附着.12例Randall斑活检标本光镜下肾乳头组织内见成团钙盐样沉积.2例电镜下肾乳头结缔组织中散在分布大小不均簇状草酸盐团聚体,典型结晶体呈针状,晶体轮廓周边电子密度高,晶体中央呈电子透亮区. 结论草酸钙结石患者肾乳头Randall斑主要是草酸盐结晶沉积,在Randall斑基础上草酸盐结晶进一步沉积可能促使草酸钙结石的形成.     

Endoscopic evidence of calculus attachment to Randall's plaque

PURPOSE: It has been proposed that calcium oxalate calculi begin as small stones attached to the renal papillae at sites of Randall's plaque. However, no study has investigated the prevalence of attached stones in calcium oxalate stone formers or the relationship between stone attachment site and Randall's plaque. In this study we used endoscopic examination of renal papillae in stone formers undergoing percutaneous nephrolithotomy to investigate both issues. MATERIALS AND METHODS: Idiopathic calcium oxalate stone formers undergoing PNL for stone removal were enrolled in this study. Multiple papillae were examined and images were recorded by digital video. The presence or absence of papillary plaque and attached stones was noted, as was the site of stone attachment. RESULTS: In 23 patients, 24 kidneys and 172 renal papillae were examined. All kidneys were found to have papillary plaque and 11 of the patients had attached stones. Most papillae (91%) contained plaque. CONCLUSIONS: The prevalence of attached stones in calcium oxalate stone formers (48%) is greater than that previously reported for the general population. Attachment appears to be on Randall's plaque. The high prevalence of attached stones and the appearance of the attachment site are consistent with a mechanism of calcium oxalate stone formation in which stones begin as plaque overgrowth.     

The role of Randall's plaques in the pathogenesis of calcium stones

PURPOSE: Knowledge of the inciting lesion in kidney stone formation has remained rudimentary until quite recently. Randall theorized that areas of apatite plaque on the renal papillae would be an ideal site for an overgrowth of calcium oxalate to develop into a calculus. We reviewed in vivo data that have further defined the role of Randall's plaques in stone disease. MATERIALS AND METHODS: We examined a set of literature that tested 2 hypotheses, that is 1) Randall's plaques are a specialized disease that begins as apatite in a unique region of the kidney due to local driving forces and anatomy, and 2) stones that arise from causes different from common calcium oxalate stones do not necessarily arise on plaque. RESULTS: Intraoperative papillary and cortical biopsy specimens obtained during percutaneous nephrolithotomy from the kidneys of 3 types of stone formers (idiopathic calcium stone formers, patients with stones due to bariatric procedures and brushite stone formers) showed unique histopathological findings. CONCLUSIONS: The metabolic and surgical pathological findings in 3 distinct groups of stone formers demonstrate that the histology of the renal papillae from a stone former is particular to the clinical setting.     

An evaluation of the physicochemical risk for renal stone disease during pregnancy

Seventeen subjects were studied during the third trimester of pregnancy (PG) and post partum (NPG) to evaluate the effect of pregnancy on the physicochemical risk of renal stone disease. Levels of urinary saturation for calcium oxalate (CaOx), brushite (Br), uric acid (UA), and monosodium urate (NaU) were determined as well as urinary excretions of stone-forming elements. In addition to urinary calcium excretion, assessment of calcium metabolism included serum calcium and parathyroid hormone. Urinary calcium excretion was 251 +/- 127 mg/day during pregnancy and 121 +/- 67 mg/day post partum (p < 0.001). This was associated with a higher intake of dietary calcium and altered renal handling of calcium with an increase in the filtered load and a decrease in renal tubular reabsorption. The increase in urinary calcium resulted in a higher level of saturation of the urine for calcium oxalate (NPG 2.1 +/- 1.0 vs PG 3.0 +/- 1.1, p < 0.02) and brushite (NPG 1.2 +/- 0.9 vs PG 1.9 +/- 1.1, p < 0.05) compatible with an increased risk of stone formation.     

Osteopontin is a critical inhibitor of calcium oxalate crystal formation and retention in renal tubules

Calcium nephrolithiasis is the most common form of renal stone disease, with calcium oxalate (CaOx) being the predominant constituent of renal stones. Current in vitro evidence implicates osteopontin (OPN) as one of several macromolecular inhibitors of urinary crystallization with potentially important actions at several stages of CaOx crystal formation and retention. To determine the importance of OPN in vivo, hyperoxaluria was induced in mice targeted for the deletion of the OPN gene together with wild-type control mice. Both groups were given 1% ethylene glycol, an oxalate precursor, in their drinking water for up to 4 wk. At 4 wk, OPN-deficient mice demonstrated significant intratubular deposits of CaOx crystals, whereas wild-type mice were completely unaffected. Retained crystals in tissue sections were positively identified as CaOx monohydrate by both polarized optical microscopy and x-ray powder diffraction analysis. Furthermore, hyperoxaluria in the OPN wild-type mice was associated with a significant 2- to 4-fold upregulation of renal OPN expression by immunocytochemistry, lending further support to a renoprotective role for OPN. These data indicate that OPN plays a critical renoprotective role in vivo as an inhibitor of CaOx crystal formation and retention in renal tubules.     

Kidney biopsy and power Doppler imaging

BACKGROUND: Practically, all complications of kidney biopsy are connected with hemorrhage. In the last years, the use of color Doppler sonography in monitoring kidney biopsies was being described, later the possibility of using power Doppler (PD) in performing kidney biopsies was presented. PD depicts the amplitude, or power, of Doppler signals rather than the frequency shift. This allows detection of a larger range of Doppler shifts and thus better visualization of small vessels, but at the expense of directional and velocity information. PATIENTS AND METHODS: Biopsy of native kidneys was performed in 144 patients. We performed real-time ultrasound-guided biopsy with an automatic biopsy device, 2-4 MHz convex probe and modified 18 G tru-cut needles were used. The vessels in the region of the biopsy were imaged with color Doppler sonography and with PD immediately before, after and the day following biopsy. RESULTS: Adequate tissue for histologic diagnosis was obtained in all patients with average 3.28 attempts at biopsy (range from 2-5). Average 24.15 (range from 7-58) glomeruli were obtained during each session. We observed complications in 6 (4.2%) patients, macrohematuria was presented in 4, and small hematoma with no need for intervention in 2 patients. In 138 (95.8%) patients, no complications were observed, microhematuria was present in 116 (80.6%) patients. CONCLUSIONS: In our study, complication rate of kidney biopsy was low and no complication requiring intervention was observed. Number of glomeruli obtained during each session was high. For better visualization of kidney vessels in biopsy path, PD was used. This additional kidney investigation itself does not essentially prolong the duration of the biopsy.     

Control of hyperoxaluria with large doses of pyridoxine in patients with kidney stones

Pyridoxine in doses of 250–500 mg daily by mouth was administered to 12 patients suffering from recurrent calcium oxalate renal calculi and idiopathic hyperoxaluria. This therapy decreased urinary oxalate excretion significantly (p<0.025) during up to 18 months of treatment. In that period eight patients showed no evidence of active stone disease; three showed slight increase in the size of their old stone(s) and one patient formed one new stone. None of these patients developed any significant complications of the therapy. These findings support the view that pyridoxine in pharmacological doses is useful in the control of elevated urinary oxalate excretion in patients with recurrent renal oxalate calculi.     

单味中药金钱草、石韦、车前子对肾结石模型大鼠的预防作用

目的：观察单味中药金钱草、石韦、车前子对肾结石的预防作用。方法：90只大鼠随机分为5组,采用1.25%乙二醇和1%氯化铵制备大鼠肾结石模型,用上述3种单味中药的免煎剂型分别给各实验组大鼠肾结石模型灌胃,对照组用枸橼酸钾,4周后观察尿和肾组织中草酸钙结晶的形成情况。结果：单味中药金钱草组、石韦组、车前子组大鼠肾内草酸钙结晶明显少于模型组,而与西药枸橼酸钾组相当。金钱草组、石韦组、车前子组大鼠尿中草酸钙结晶的排泄均明显多于模型组。结论：单味中药金钱草、石韦、车前子对预防大鼠肾结石的形成有确切效果,并与西药枸橼酸钾相当,其作用可能主要是通过增加尿中草酸钙结晶的排泄而达到的。     

Oxalate transport and calcium oxalate renal stone disease

Hyperoxaluria is considered to play a crucial role in calcium oxalate (CaOx) renal stone disease. The amount of oxalate excreted into the urine depends on intestinal absorption, endogenous production, renal clearance and renal tubular transport. Since a primary disorder has not been found so far in most CaOx stone formers and since oxalate is freely filtered at the glomerulus, most studies are presently focussed on alterations in epithelial oxalate transport pathways. Oxalate can be transported across an epithelium by the paracellular (passive) and transcellular (active) pathway. Oxalate transport across cellular membranes is mediated by anion-exchange transport proteins. A defect in the structure of these transport proteins could explain augmented transcellular oxalate transport. Little is known about the physiological regulation of oxalate transport. In this review cellular transport systems for oxalate will be summarized with special attention for the progress that has been made to study oxalate transport in a model of cultured renal tubule cells. Better understanding of the physiological processes that are involved in oxalate transport could yield information on the basis of which it might be possible to design new approaches for an effective treatment of CaOx stone disease.     

Hyperoxaluria in idiopathic calcium nephrolithiasis--what are the limits?

OBJECTIVE: The object of this study was to investigate the role for measurement of 24-h renal oxalate excretion in the evaluation of idiopathic calcium stone formers. MATERIALS AND METHODS: Renal excretion rates of oxalate and creatinine were measured in 24-h urines in 46 consecutive male recurrent idiopathic calcium stone formers and 61 healthy males. Furthermore, day-to-day variation in renal oxalate excretion in 10 male recurrent stone formers and 10 healthy males were evaluated by measuring 24-h oxalate excretion on 5 different days in each individual. Concentrations of oxalate in urine were measured using an enzymatic method without ascorbate interference. RESULTS: The cumulative frequency distribution curves of 24-h renal oxalate excretion rates of stone formers and controls were congruent, and there were no statistically significant differences in oxalate excretion rates between stone formers and controls. Mean 24-h oxalate excretion (95%-confidence intervals) was 0.22 (0.18-0.25) mmol and 0.21 (0.18-0.24) mmol in stone formers and controls, respectively (p = 0.9). The day-to-day variation study did not reveal any differences in renal oxalate excretion pattern between stone formers and controls, and the presence of intermittent hyperoxaluria could not be confirmed. The oxalate excretion rates were generally low. CONCLUSION: In our region, there appear to be no differences in 24-h renal excretion rates of oxalate between male recurrent idiopathic calcium stone formers and healthy males, and the syndrome of mild hyperoxaluric calcium nephrolithiasis could not be identified in our population of idiopathic stone formers. Hence, a limit of abnormal oxalate excretion that distinguishes an idiopathic stone former from a non-stone former could not be defined in our population. Therefore, the value of routine measurement of urinary oxalate in idiopathic urolithiasis is difficult to accept, and cannot be recommended.     

Inhibitory effect of fluoride on renal stone formation in rats.

The effect of fluorine (F) on stone formation induced by ethylene glycol (EG) was studied in rats. For different groups, the drinking water was supplemented with EG, sodium fluoride (NaF), EG+NaF, or nothing as control. An isotope-tracing method was used to evaluate experimental stone formation in the kidneys by introducing 45Ca intraperitoneally into rats and then measuring the radioactivity of the kidney. At the end of the 4-week experiment, rats of the EG+NaF group showed a significantly lower incidence of gross urinary stones and lower 45Ca activity in their kidneys compared to the EG group of rats. Both the EG group and EG+NaF group had markedly increased urinary oxalate excretion, with the latter significantly lower than the former (p less than 0.05). Urinary oxalate excretion was relatively lower in the NaF group than in the control group. This study indicates that NaF can inhibit renal stone formation induced by EG by decreasing oxalate synthesis and urinary oxalate excretion, and suggests a possible clinical therapeutic value of NaF in the prevention of oxalate kidney stones.     

Prevalence of hyperoxaluria in idiopathic calcium oxalate kidney stone disease

Urinary excretion of oxalate, calcium and urate has been investigated in 88 patients affected by idiopathic calcium oxalate stone disease and in 20 normal subjects. Of these ions, only oxalate was found significantly higher in stone formers. Defining hyperoxaluria as urinary oxalate excretion greater than 2 SD above normal, 50% of stone-forming people were found to be hyperoxaluric. When stone formers were classified in normo- and hyperoxaluric, the prevalence of hypercalciuria, hyperuricuria, family history of stone disease and recurrencies in stone formation was the same in both groups. It is concluded that hyperoxaluria is a frequent finding in finding in idiopathic calcium oxalate renal stone disease.