Effects of oral pyridoxine upon plasma and 24-hour urinary oxalate levels in normal subjects and stone formers with idiopathic hypercalciuria

Summary The effect of pyridoxine hydrochloride, 200 mg/day (0.97 mmol/day) for 3 weeks, upon plasma and urinary oxalate has been determined in ten normal subjects and seven patients with idiopathic hypercalciuria while both groups were on low-oxalate diets. Patients had higher basal urinary oxalate levels than normal subjects. In normal subjects pyridoxine administration decreased plasma oxalate levels and raised urinary oxalate. The patients showed no change in either plasma or urinary oxalate.     

Reduction of Oxalate Content of Foods by the Oxalate Degrading Bacterium,Eubacterium Lentum WYH-1

Background : Urinary oxalate may contribute far more than urinary calcium to the pathogenesis of urinary calculi. Urinary oxalate may be reduced by restricting the intake of foods high in oxalate. The oxalate content of foods might be reduced by oxalate-degrading bacteria. The purpose of this experiment was to reduce the oxalate content of foods with an oxalate-degrading bacterium which was isolated from the feces of a Japanese male. Methods : An artificial intestinal juice was prepared by modifying Rogosa medium. An infusion of black tea was prepared from a commercial tea bag. The oxalate-degrading bacteria used were Eubacterium lentum WYH-1 which we have isolated. To 5 mL of the above oxalate-containing artificial intestinal juice and infusion of black tea, 0.5 mL of the bacterial culture was added and incubated anaerobically at 37°C. Oxalic acid in the supernatant of the culture medium was assayed by high-performance liquid chromatography. Results : In 24 hours, 1 × 10⁶ cells/mL of Eubacterium lentum WYH-1 decomposed 100% of 1 mg/mL oxalate in the artificial intestinal juice. The oxalate in the black tea infusion (1 mg/mL) was also decomposed completely within 48 hours by 1 × 10⁷ cells/mL of the bacteria. Conclusion : Eubacterium lentum WYH-1 was able to efficiently decompose the oxalate in foods.     

Calcium oxalate trihydrate in urinary calculi

Summary Visual examination, electron-microscopic observation and infrared-spectroscopic analysis demonstrate that the thermodynamically unstable calcium oxalate trihydrate, which supposedly plays an important role in the formation of certain urinary calculi, is a commonly occurring constituent of urinary stones.     

Potential nephrotoxicity of intravenous infusions of naftidrofuryl oxalate

We report two cases of acute renal failure in patients witharteriosclerosis obliterans treated by intravenous infusionof naftidrofuryl oxalate. At renal biopsy the histological lesionswere identical with those found in ARF due to hyperoxaluriaof other causes, revealing tubular epithelial necrosis and massiveintra-tubular precipitation of calcium oxalate monohydrate (Cl)crystals. A second study was then conducted in four other patientswith arteriosclerosis obliterans to evaluate serum and urinarylevels of oxalate, and crystalluria during the intravenous administrationof 800 mg of naftidrofuryl oxalate per day for 10 days. Duringthe course of treatment, the serum and urinary oxalate levelswere found to increase substantially, with the gradual onsetof massive Cl crystalluria. These results indicate that naftidrofuryloxalate was responsible for the acute renal failure in the firsttwo patients. High intravenous doses of naftidrofuryl oxalatemust be used cautiously, with close surveillance of renal function.     

Calcium stone disease: a multiform reality

In calcium renal stones, calcium oxalate and calcium phosphate in various crystal forms and states of hydration can be identified. Calcium oxalate monohydrate (COM) or whewellite and calcium oxalate dihydrate (COD) or weddellite are the commonest constituents of calcium stones. Calcium oxalate stones may be pure or mixed, usually with calcium phosphate or sometimes with uric acid or ammonium urate. The aim of this study was to compare the clinical and urinary patterns of patients forming calcium stones of different composition according to infrared spectroscopic analysis in order to obtain an insight into their etiology. The stones of 84 consecutive calcium renal stone formers were examined by infrared spectroscopy. In each patient, a blood sample was drawn and analysed for serum biochemistry and a 24-h urine sample was collected and analysed for calcium, phosphate, oxalate, citrate and other electrolytes. We classified 49 patients as calcium oxalate monohydrate (COM) stone formers, 32 as calcium oxalate dihydrate (COD) stone formers and three as apatite stone formers according to the main component of their stones. Patients with COM stones were significantly older than patients with COD stones (P<0.002). Mean daily urinary calcium and urinary saturation with respect to calcium oxalate were significantly lower in patients with COM than in those with COD stones (P<0.000). Patients with calcium oxalate stones containing a urate component (10%) presented with higher saturation (P<0.012) with respect to uric acid in their urine (and lower with respect to calcium oxalate and calcium phosphate, respectively P<0.024 and P<0.003) in comparison with patients without a urate component in the stone. Patients with calcium oxalate stones with a calcium phosphate component (15%) showed higher (P<0.0016) urinary saturation levels with respect to calcium phosphate (and lower with respect to uric acid (P<0.009), compared with patients forming stones without calcium phosphate or with a low calcium phosphate component. Patients with calcium stones mixed with urate had a significantly lower urinary pH (P<0.002) and urinary calcium (P<0.000), and patients with calcium phosphate >15%, higher urinary pH (P<0.004) and urinary calcium (P<0.000). In conclusion, in the evaluation of the individual stone patient, an accurate analysis of the stone showing its exact composition and the eventual presence of minor components of the stone is mandatory in order to plan the correct prophylactic treatment. Patients with calcium stones could require various approaches dependent on the form and hydration of the calcium crystals in their stones, and on the presence of minor crystalline components that could have acted as epitaxial factors.     

Influence of cranberry juice on the urinary risk factors for calcium oxalate kidney stone formation

Cranberry juice is popular remedy for many ills; apart from the pleasant tasting many people drink it to help in preventing UTIs and stones. Authors from Cape Town (where there is the added benefit of an excellent climate) assessed the influence of cranberry juice on urinary risk factors for calcium oxalate calculi in a randomized crossover trial, showing that it has anti‐lithogenic properties. In the second paper, authors from Jerusalem report on 14 patients with distal ureteric strictures after kidney transplantation, all of whom were treated endourologically. They found transurethral incision of the distal ureteric stricture to be effective.

OBJECTIVE

To investigate the potential influence of cranberry juice on urinary biochemical and physicochemical risk factors associated with the formation of calcium oxalate kidney stones, as this product might affect the chemical composition of urine.

SUBJECTS AND METHODS

Urinary variables were assessed in a randomized cross‐over trial in 20 South African men (students) with no previous history of kidney stones. The first group of 10 subjects drank 500 mL of cranberry juice diluted with 1500 mL tap water for 2 weeks, while the second group drank 2000 mL of tap water for the same period. This was followed by a 2‐week ‘washout’ period before the two groups crossed over. During the experimental phase subjects kept a 3‐day food diary to assess their dietary and fluid intakes; 24‐h urine samples were collected at baseline and on day 14 of the trial periods, and analysed using modern laboratory techniques. Urine analysis data were used to calculate the relative urinary supersaturations of calcium oxalate, uric acid and calcium phosphate. Data were assessed statistically by analysis of variance.

RESULTS

The ingestion of cranberry juice significantly and uniquely altered three key urinary risk factors. Oxalate and phosphate excretion decreased while citrate excretion increased. In addition, there was a decrease in the relative supersaturation of calcium oxalate, which tended to be significantly lower than that induced by water alone.

CONCLUSION

Cranberry juice has antilithogenic properties and, as such, deserves consideration as a conservative therapeutic protocol in managing calcium oxalate urolithiasis.

     

Oxalate and its handling in a low stone risk vs a stone-prone population group

Despite hyperoxalurogenic eating habits relative to white subjects, South African blacks have urinary oxalate excretions, Tiselius risk indices (AP_CaOx) and calcium oxalate saturations, which do not differ significantly from those of their white counterparts. The present study was undertaken to establish whether the BONN-Risk-Index (BRI) might discriminate between the urines of the two population groups and whether differences might exist in their respective gastrointestinal absorption rates of oxalate. Participants (n=15 in each group) provided 24 h urines on their free diets for BRI determination. Gastrointestinal oxalate absorption was measured using the [¹³C₂]oxalate absorption test. Results showed that BRI values were significantly lower in black subjects (2.04 vs 4.90, P=0.034), but that there was no difference in the oxalate absorption between the groups (10.30 vs 9.95%, P=0.87). These results suggest that South African black subjects handle dietary oxalate more efficaciously than white subjects and that this occurs via some endogenous mechanism, which has not yet been identified or characterized.     

晶体表面结合蛋白对草酸钙晶体生长的抑制作用

为观察晶体表面结合蛋白（ＣＳＢＰ）对草酸钙晶体生长的影响，用层析法分离提取正常人和草酸钙结石病人ＣＳＢＰ，应用种晶体技术检测ＣＳＢＰ、尿凝血酶原激活肽Ｆ１片段（ＵＰＴＦ１）和白蛋白在体外对草酸钙晶体生长的作用。结果发现正常人ＣＳＢＰ和ＵＰＴＦ１能显著抑制草酸钙晶体的生长，结石病人ＣＳＢＰ的抑制活性低于正常人。提示病人ＣＳＢＰ中ＵＰＴＦ１减少致抑制活性降低与结石形成有关     

Ascorbic acid in idiopathic recurrent calcium urolithiasis in humans – does it have an abettor role in oxalate, and calcium oxalate crystallization?

The role of ascorbic acid (ASC) in the pathophysiology of renal calcium stones is not clear. We evaluated ASC in blood and urine of fasting male patients with idiopathic calcium urolithiasis (ICU) and healthy volunteers. Using smaller subgroups, we also evaluated their response to exogenous ASC [either intravenous or oral ASC (5 mg/kg bodyweight)] administered together with an oxalate-free test meal. The influence of ASC on calcium oxalate crystallization, the morphology of crystals at urinary pH 5, 6 and 7, and the effect of increasing duration of urine incubation on urinary oxalate at these pHs, without and with addition of ASC, were studied too. In normo- and hypercalciuric ICU, blood and urinary ASC from fasting patients remained unchanged, but the slope of the regression line of urinary ASC versus urinary oxalate was steeper than in the controls; the plasma ASC half-life did not differ between controls, normo- and hypercalciuric ICU; the ASC-supplemented meal caused an increase in the integrated plasma oxalate in the normocalciuric subgroup versus controls. In normo- and hypercalciuric ICU urinary oxalate, the oxalate/glycolate ratio, and calcium oxalate supersaturation were increased, but urinary glycolate was unchanged. In the controls, oral ASC did not affect calcium oxalate crystallization, while in ICU, ASC inhibited crystal growth. In control urine calcium oxalate dihydrate and calcium oxalate monohydrate develops, while in ICU urine only the former crystal type develops. In vitro oxalate neoformation from ASC did not occur. It was concluded that (1) under normal conditions an abettor role of ASC for renal stones is not recognizable, (2) in ICU, urinary oxalate excess unrelated to degradation of exogenous ASC is exhibited, and that this is most likely unrelated to an initial increase in oxalate biosynthesis, and (3) ASC appears to modulate directly calcium oxalate crystallization in ICU, although the true mode of action is still not known. Received: 24 September 1999 / Accepted: 16 December 1999     

复发性草酸钙结石与尿内酸性粘多糖的关系

为了探讨酸性粘多糖（ＧＡＧｓ）对草酸钙结石形成的抑制作用机理，收集了１２例正常人及１５例复发性草酸钙结石病人２４小时尿，经超滤后，用ＰｒｏｎａｓｅＥ蛋白酶降解尿中糖蛋白，纯化ＧＡＧｓ，并分别测定了蛋白水解前后尿样中ＧＡＧｓ含量及种晶体系下ＧＡＧｓ对草酸钙晶体粒度分布。结果表明：（１）水解前后，正常人尿中ＧＡＧｓ含量均比结石病人高；（２）草酸钙晶体生长抑制指数（Ｉｇ）、聚集抑制指数（Ｉａ）与ＧＡＧｓ的含量成正比。     

Production of calcium oxalate monohydrate,dihydrate or trihydrate

Summary Procedures to obtain calcium oxalate monohydrate, dihydrate and trihydrate are presented and discussed. The influence of several additives and conditions in the formation of calcium oxalate dihydrate crystals are compartatively evaluated. It seems that the presence of colloidal phosphate favours the formation of calcium oxalate dihydrate crystals through heterogeneous nucleation.     

一水草酸钙与二水草酸钙结石形成机理的研究

目的　探讨一水草酸钙（ＣＯＭ） 与二水草酸钙（ＣＯＤ） 结石形成的机制。　方法　应用红外光谱仪对２５８ 块尿结石成分进行检测,同时检测３０ 例患者２４ｈ 尿液生化指标,对测定结果利用ＳＰＳＳ软件进行ｔ 检验。　结果　（１） 尿钙：ＣＯＭ 组（４．８３ ±１ ．９８）ｍ ｍｏｌ／２４ｈ,ＣＯＤ 组（９．８８ ±４ ．２８）ｍｍｏｌ／２４ｈ,Ｐ＜ ０ ．０１ ;（２） 尿磷：ＣＯＭ 组（１９ ．４０ ±９．６９）ｍ ｍｏｌ／２４ｈ,ＣＯＤ 组（２９．２０ ±１２．００）ｍ ｍｏｌ／２４ｈ,Ｐ＜ ０．０５,两组尿钙、尿磷差异有显著性。　结论　二水草酸钙结石患者尿钙、尿磷高于一水草酸钙结石患者,表明二水草酸钙的形成与高钙尿及磷酸盐异质成核有关,而一水草酸钙的形成可能与尿中抑制物缺乏有关。     

草酸钙晶体表面结合蛋白质的研究

目的 了解草酸钙晶体表面结合蛋白质在结石形成的过程中的作用。方法 用草酸钙过饱和结晶法制备正常人和草权钙结石患者尿草酸钙晶体表面结合物质（ＣＳＢＳ）,经ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ柱层析分离蛋白质和葡胺聚糖,用ＳＤＳ－聚丙烯酰胺凝胶电泳（ＳＤＳ－ＰＡＧＥ）测定蛋白质组成和分子量,用氨基酸自动分析仪测定蛋白质的氨基酸,结果;正常仍ＣＳＢＳ中主要含分子量为３１０００的尿凝血酶原激活肽片段１（     

Detection and identification of oxalate-degrading bacteria in human feces.

BACKGROUND: Oxalate is detoxified (catabolized) via the action of two enzymatic proteins, formyl coenzyme A transferase (encoded by the frc gene) and oxalyl coenzyme A decarboxylase (encoded by the oxc gene), contained in the cytosol of Oxalobacter formigenes that colonizes the human intestinal tract. It is speculated that oxalate-degrading bacteria decrease oxalate absorption from the intestines and their absence in the gastrointestinal tract correlates with the formation of calcium-oxalate urolithiasis. METHODS: Two methods of detection and identification of this bacterial strain were studied in human fecal samples collected from Japanese subjects. Genomic DNA was isolated from bacterial culture, and specific 16S rDNA was amplified by polymerase chain reaction (PCR) followed by sequencing. The oxc gene was amplified directly from human feces by PCR using the specific primers. RESULTS: Oxalate-degrading bacteria were identified by comparing the sequences of 16S rDNA. The oxc gene was directly detected from human feces by PCR. It was ascertained that a combined PCR detection method using both 16S rDNA and the oxc gene allows for identification of O. formigenes in human fecal samples. CONCLUSION: This detection and identification method of oxalate-degrading bacteria using 16S rDNA and oxc gene should be applied in examination of clinical samples.     

尿草酸钙晶体基质蛋白的分离及理化特征

为了进一步了解晶体基质蛋白（ＣＭＰ）的理化特性和其在结石形成中的作用，利用ＤＥＡＥＳｅｐｈａｄｅｘＡ５０、ＳｅｐｈａｄｅｘＧ２００对草酸钙结晶中的基质蛋白进行了分离，并用ＳＤＳＰＡＧＥ、双向电泳和Ｗｅｓｔｅｒｎｂｌｏｔ进行检测。结果表明：ＣＭＰ是草酸钙过饱和方法制备的晶体基质中的主要成分，其分子量为３１０００，等电点为５．０～５．５；Ｗｅｓｔｅｒｎｂｌｏｔ证明与抗人凝血酶原抗体有交叉反应。结果认为ＣＭＰ是活化的人凝血酶原片段     

The effect of crystalline monosodium urate on the crystallisation of calcium oxalate in whole human urine

Summary (1) Samples of undiluted urine from normal men were preincubated with crystalline monosodium urate and their metastable limits and responses to a standard oxalate challenge were compared with results obtained from control samples preincubated without urate. (2) Preincubation with urate had no significant effect on the metastable limits of the urines, the morphology, size, or growth rates of calcium oxalate crystals precipitated from the urines, or on the total amount of calcium oxalate deposited in a given time. (3) It was concluded that particulate monosodium urate is unlikely to influence calcium oxalate stone formation by binding to and attenuating the potency of urinary inhibitors.     

正常人和草酸钙结石病人尿草酸钙晶体基质

以改良Ｍｏｒｓｅ和Ｒｅｓｎｉｃｋ法提取１０例上尿路草酸钙结石病人和１１例正常人的尿草酸钙晶体基璺，用双向聚丙烯酰胺凝胶电泳对晶体基质及结晶前后大分子物的蛋白质组成进行了比较分析。     

Study of a rat model for calcium oxalate crystal formation without severe renal damage in selected conditions

BACKGROUND: Although nephrotoxic in high doses, ethylene glycol (EG) has been used with ammonium chloride (NH(4)Cl) or vitamin D(3) to study calcium oxalate stone formation in rat models. In the present study we used EG alone or with NH(4)Cl to study hyperoxaluria, crystaluria, and crystal attachment to renal epithelial cells in rats with minimal renal damage. METHODS: Six-week-old male Sprague-Dawley (SD) rats were given food and special drinking water. In experiment 1 the drinking water contained 1.0% NH(4)Cl plus four different concentrations of EG (0.8%, 0.4%, 0.2%, 0.1%). In experiment 2 the drinking water contained EG alone (0.8%, 0.4%, 0.2%, 0.1%). Urine was collected for 24 h before the rats were sacrificed. In experiment 1 the rats were sacrificed 5-13 days after starting the special water. In experiment 2 the rats were sacrificed 7-21 days after starting the special water. Bladder urine was also obtained. Blood and urine were tested for calcium, phosphorus, and creatinine. In addition, urine was tested for pH, oxalate and N-acetyl-beta-D glucosaminidase (NAG). Kidney sections were stained with hematoxylin-eosin, von Kossa and Pizzolato stain. Crystal morphology was determined using polarizing microscopy, and composition was determined using high-resolution X-ray powder diffraction. RESULTS: Experiment 1: Aggravation of renal function, an increase in urinary oxalate and NAG excretion, and crystals observed in the kidneys all correlated with EG concentration and length of drinking time. In bladder urine, calcium oxalate monohydrate (COM) crystals exceeded calcium oxalate dihydrate (COD) crystals. Experiment 2: Renal function remained unchanged. Oxalate excretion increased and NAG increased slightly. Crystals occurred only in the papillary tip region. Crystals in bladder urine were mostly COD. CONCLUSION: In the current rat model, calcium oxalate crystaluria could be induced without severe renal damage in selected cases. Either and/or both COM and COD might form and interact with kidney epithelium. We propose different experimental conditions to study the various phases of calcium oxalate stone formation in young male SD rats.     

Identificación endoscópica de la composición de los cálculos urinarios: un estudio del Southeastern Group for Lithiasis Research (SEGUR 2)

Introduction and objectivesTo assess the surgeon's ability to evaluate the composition of the stone by observation of endoscopic images.Materials and methodsA series of 20 video clips of endoscopic treatments of urinary stones of which was also available the result of infrared spectroscopy was uploaded to a YouTube site accessible only to members of the South Eastern Group for Urolithiasis Research (SEGUR) who were asked to identify the composition of the stones.ResultsA total of 32 clinicians from 9 different countries participated in the study. The average number of correct detections of participants was 7.81 ± 2.68 (range 1-12). Overall accuracy was 39% (250 out of 640 predictions). Calcium oxalate dihydrate stones have been correctly detected in 69.8%, calcium oxalate monohydrate in 41.8%, uric acid in 33.3%, calcium oxalate/uric acid in 34.3% and cystine in 78.1%. Precision rates for struvite (15.6%), calcium phosphate (0%) and mixed calcium oxalate/calcium phosphate (9.3%) were quite low.ConclusionsObservation of the stone during the endoscopic procedure was not reliable to identify the composition of most stones although it gave some information allowing to identify with a good sensitivity calcium oxalate dihydrate and cystine stones. Nevertheless, photo or video reporting of the intact stone and its internal structure could should be encouraged to implement results of still mandatory post-operative stone analysis. Endourologists should improve their ability of visual identification of the different types of stones.     

Experimental technique simulating oxalocalcic renal stone generation

Summary A new technique simulating some of the conditions experienced by papillar and caliceal oxalocalcic stones during the early stages of their generation was developed. This technique enables the study of how conditions prevailing at calculogenesis, such as pH, composition of urine and presence of admixtures, influence the rate of formation and development, the crystalline texture and the composition of the concretion formed. Results achieved with this technique demonstrate that: (1) an appropriate substrate always gives rise to a crystalline concretion if it is in contact with supersaturated urine; (2) primary agglomeration plays a significant role in concretion development whereas secondary agglomeration is of minor importance; and (3) citrate and pyrophosphate exert a considerable influence on the shape and composition of particles constituting the concretion.