The regional educational impact of a Renal Stone Center

This study evaluates the impact of the Renal Stone Center (RSC) at Yale University School of Medicine on the extent of the diagnostic search for urolithiasis risk factors at the Yale-New Haven Medical Center and four affiliated community hospitals. Using a multiple time series design and a Physician Performance Index (PPI) based on multiple normative practice criteria, the hospital and outpatient charts of 1,924 patients with a primary diagnosis of urolithiasis at the five hospitals were examined to determine whether there was a change over time that could be related to the RSC. There was no statistically significant improvement in the PPI at four of the five hospitals. At the fifth, there was a statistically significant improvement that possibly was related to factors other than the RSC. Routine blood, urine, and X-ray tests usually were performed well. However, the history of urolithiasis risk factors and the examination of 24-hour urines were generally done poorly or not at all, and this generalization held true (although modified somewhat) even when physician office records were examined as well.     

Microelements in Stones,Urine, and Hair of Stone Formers: A New Key to the Puzzle of Lithogenesis?

The role of trace elements in lithogenesis is still unclear. The aim of this study was to evaluate the levels of elements in urinary stones and in the urine and hair of stone formers to identify these elements that have synergic correlations in studied materials and may contribute to lithogenesis. A total of 219 consecutive patients with idiopathic upper urinary tract stones were prospectively enrolled in the study. Urine and hair samples were collected from all patients. The content of the stone was evaluated using atomic absorption spectrometry, spectrophotometry, and colorimetric methods. The analysis of 29 elements in stones and hair and 21 elements in urine was performed using inductively coupled plasma-atomic emission spectrometry. The strength of correlation was described with the value of Spearman’s rank correlation coefficient. The positive correlation between concentration of sodium, potassium, magnesium, barium, vanadium, zinc, silicon, phosphorus, and iodine in phosphate stones was observed. Only a few incidental correlations between the composition of stones and the distribution of elements in urine and in hair were found. There were 109 positive two-element correlations between two materials. The most common were observed for vanadium, aluminum, lead, cobalt, and molybdenum. Two-element positive correlations for all samples were established only for three elements: vanadium, lead, and aluminum. Results indicate that analysis of particular elements in hair and urine cannot predict the composition of urinary stones. This study showed, for the first time, correlations between the levels of vanadium, lead, and aluminum in the stones, urine, and hair of stone formers.     

Excretion of inhibitors of calcification in urine. Part I. Findings in control subjects and patients with renal stones.

The total excretion of inhibitors of in vitro calcification was measured (in inhibiting units per day) in 24-hour urine samples of 11 control subjects and 20 patients with renal calculi. A semiquantitative method incorporating the rachitic rat cartilage technique was used. In both groups there was a significant positive correlation between the number of inhibiting units per day and the daily urine volume. The mean number of inhibiting units per day was significantly (P smaller than 0.05) higher in the stone patients than in the controls. However, the stone-formers had significantly larger (P smaller than 0.01) 24-hour urine volumes. When corrections were made for urine volume there was no significant difference between the two groups. These data suggest that the underlying abnormality responsible for renal stone formation is not a persistent decrease in the total concentration of urinary inhibitors of calcification.     

Idiopathic calcium nephrolithiasis. 2. Differences between hypercalciuric and normocalciuric persons with recurrent kidney stone formation and persons without such a history.

Normocalciuric and hypercalciuric patients with idiopathic recurrent calcium nephrolithiasis were compared with healthy individuals without such a history to examine the factors that predispose normocalciuric patients to stone formation. The urine calcium excretion rate was higher in the normocalciuric patients than in the control subjects (227 v. 183 mg/24 h; P less than 0.01), but the urine calcium concentration was not significantly different. The urine magnesium and citrate excretion rates and concentrations were lower in the normocalciuric patients than in the control subjects (P less than 0.001), while the urine uric acid and oxalate excretion rates and concentrations and the urine saturation with brushite (CaHPO4-2H2O) were not significantly different. These results suggest the importance of slight increases in the urine calcium excretion rate together with decreased urine magnesium and citrate excretion rates in normocalciuric persons with recurrent calcium stone formation. The urine of the hypercalciuric patients was more highly saturated with brushite than the urine of the normocalciuric patients and the control subjects, and the excretion rates of uric acid and oxalate were increased in the hypercalciuric patients. The hypercalciuric patients had a higher urine creatinine excretion rate than the normocalciuric patients and a higher daily urine volume than the control subjects, which suggests that differences in lean body mass or fluid and food intake, or both, may be important determinants of these differences in crystalloid excretion. As in the normocalciuric patients, the urine citrate excretion rate and concentration were decreased in the hypercalciuric patients compared with the control subjects.     

A Pilot Study of the Effect of Sodium Thiosulfate on Urinary Lithogenicity and Associated Metabolic Acid Load in Non-Stone Formers and Stone Formers with Hypercalciuria

Background and Objectives

Sodium thiosulfate (STS) reduced calcium stone formation in both humans and genetic hypercalciuric stone forming (GHS) rats. We sought to measure urine chemistry changes resulting from STS administration in people.

Design, Setting, Participants & Measurements

STS was given to healthy and hypercalciuric stone forming adults. Five normal non-stone forming adults (mean age 33 years), and 5 people with idiopathic hypercalciuria and calcium kidney stones (mean age 66 years) participated. Two baseline 24-hour urine collections were performed on days 2 and 3 of 3 days of self-selected diets. Subjects then drank STS 10 mmol twice a day for 7 days and did urine collections while repeating the self-selected diet. Results were compared by non-parametric Wilcoxon signed rank test. The primary outcome was the resulting change in urine chemistry.

Results

STS administration did not cause a significant change in urinary calcium excretion in either group. In both groups, 24 hour urinary ammonium (P = 0.005) and sulfate excretion (P = 0.007) increased, and urinary pH fell (P = 0.005); citrate excretion fell (P<0.05) in hypercalciuric participants but not in non-stone formers. Among stone formers with hypercalciuria, 3 of 5 patients had measurement of serum HCO₃ concentration after the STS period: it did not change. The net effect was an increase in supersaturation of uric acid, and no change in supersaturation of calcium oxalate or calcium phosphate.

Conclusions

The basis for studies demonstrating that STS prevented stones in rats and people was not reflected by the changes in urine chemistry reported here. Although serum HCO₃ did not change, urine tests suggested an acid load in both non-stone forming and hypercalciuric stone-forming participants. The long term safety of STS needs to be determined before the drug can be tested in humans for long-term prevention of stone recurrence.     

Determination of urinary succinylacetone by capillary electrophoresis for the diagnosis of tyrosinemia type I

The presence of succinylacetone in urine or blood or amniotic fluid is pathognomonic of an inherited metabolic disorder, named tyrosinemia type I. We developed a capillary electrophoretic method for the fast analysis of succinylacetone in urine samples. The separation was performed at reversed polarity mode using either a cationic surfactant as the buffer additive, or a capillary coated with a positively charged polyelectrolyte. Under these conditions, urine samples were directly injected to the capillary without any pretreatment step. The utility of the method was demonstrated by the identification of succinyacetone in urine from patients with hereditary tyrosinemia type I. For all patients, diagnostic peaks at the expected migration times were detected. The developed method is rapid, simple, inexpensive, and suitable for the determination of succinylacetone in clinical urine samples.     

2,8-Dihydroxyadenine Urolithiasis: A Not So Rare Inborn Error of Purine Metabolism

Adenine phosphoribosyltransferase (APRT) deficiency is a rare inherited metabolic disorder that leads to the formation and hyperexcretion of 2,8-dihydroxyadenine (DHA) into urine. The low solubility of DHA results in precipitation and formation of urinary crystals and kidney stones. The disease can be present as recurrent urolithiasis or nephropathy secondary to crystal precipitation into renal parenchyma (DHA nephropathy). The diagnostic tools available, including stone analysis, crystalluria, and APRT activity in red blood cells, make the diagnosis easy to confirm when APRT deficiency is suspected. However, the lack of recognition of this metabolic disorder frequently resulted in a delay in diagnosis and treatment with grave consequences. The early recognition and treatment of APRT deficiency are of crucial importance to prevent irreversible loss of renal function. This review summarizes the genetic and metabolic mechanisms underlying DHA stones formation and chronic kidney disease, along with the issues of diagnosis and management of APRT deficiency. Moreover, we report the mutations in the APRT gene responsible for APRT deficiency in 51 French patients (43 families) including 22 pediatric cases (18 families) among the 64 patients identified in the biochemistry laboratories of Necker Hospital, Paris (1978–2013).     

Stability of 5-aminolevulinic acid on dried urine filter paper for a diagnostic marker of tyrosinemia type I

The chemical diagnosis of tyrosinemia type I generally involves the detection of succinylacetone (SA) in patient urine. However, 5-aminolevulinate (5ALA), which accumulates due to succinylacetone's inhibition of porphyrin synthesis, can also be used as diagnostic metabolites. Here we examined the stabilities of these markers on dried urine filter paper. After two weeks at room temperature, the succinylacetone was 10% of its original level, but over 80% of 5-aminolevulinate remained. Thus, although insufficient succinylacetone was recovered from dried urine filter paper to diagnose tyrosinemia type I, 5-aminolevulinate was readily detected, permitting the diagnosis.     

Urine citrate and renal stone disease.

Calcium stone disease is attributable to supersaturation of the urine with calcium and other salts, the presence of substances that promote crystallization and a deficiency of inhibitors of crystallization. Citrate is a potent inhibitor of calcium oxalate and calcium phosphate stone formation whose excretion is diminished in some patients with stone disease owing to idiopathic causes or secondary factors such as bowel disease and use of thiazides. The pH within the proximal tubule cells is an important determinant of citrate excretion. Multivariate analysis has shown that the urine concentrations of calcium and citrate are the most important factors in stone formation. In uncontrolled studies potassium citrate, which increases urinary citrate excretion, appears to be promising as a therapeutic agent for patients with stone disease and hypocitraturia refractory to other treatment. On the other hand, there are potential drawbacks to sodium alkali therapy, such as the precipitation of calcium phosphates.     

Management of Patients with Urinary Calculi

A retrospective survey was made of 305 patients with proved urinary calculi. When those patients with a solitary stone were compared with those with multiple stones no diagnostically helpful difference was noted in the prevalence of abnormal serum or urine biochemistry, urinary infection, or anatomical abnormality of the urinary tract. The same was true of the stone composition and the need for surgery. It seems that neither routine radiological examination nor regular follow-up is likely to help identify patients whose stones are going to recur.     

The NMR study of human biological fluids for detection of pathologies NMR study of biological fluids

The paper deals with the NMR spectra obtained using preparations of five different human biological body fluids. Characteristic metabolite signals of blood, urine, tears, saliva, and sweat spectra have been determined and classified. The biological body fluid samples were used for search and identification of biomarkers of cardiovascular disease. Absolute functional biomarkers for diseases such as coronary heart disease (CHD) have not been recognized even in the case acute myocardial infarction. A hypothesis explaining reasons of lack of such markers has been formulated. The results of comparative analysis of blood and urine samples from humans and some laboratory animals are given. Identify and analyze signals of metabolites of pathogenic microflora and their dynamics in the urine from patients with urogenital diseases have been determined and analyzed and characteristic biomarkers have been recognized.     

A systematic review of humoral immune responses against tumor antigens

This review summarizes studies on humoral immune responses against tumor-associated antigens (TAAs) with a focus on antibody frequencies and the potential diagnostic, prognostic, and etiologic relevance of antibodies against TAAs. We performed a systematic literature search in Medline and identified 3,619 articles on humoral immune responses and TAAs. In 145 studies, meeting the inclusion criteria, humoral immune responses in cancer patients have been analyzed against over 100 different TAAs. The most frequently analyzed antigens were p53, MUC1, NY-ESO-1, c-myc, survivin, p62, cyclin B1, and Her2/neu. Antibodies against these TAAs were detected in 0–69% (median 14%) of analyzed tumor patients. Antibody frequencies were generally very low in healthy individuals, with the exception of few TAAs, especially MUC1. For several TAAs, including p53, Her2/neu, and NY-ESO-1, higher antibody frequencies were reported when tumors expressed the respective TAA. Antibodies against MUC1 were associated with a favorable prognosis while antibodies against p53 were associated with poor disease outcome. These data suggest different functional roles of endogenous antibodies against TAAs. Although data on prediagnostic antibody levels are scarce and antibody frequencies for most TAAs are at levels precluding use in diagnostic assays for cancer early detection, there is some promising data on achieving higher sensitivity for cancer detection using panels of TAAs. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Liquid chromatographic—mass spectrometric analysis for screening of patients with cystinuria, and identification of cystine stone

Analyses of amino acids in the urine of a normal human and of patients with heterozygous and homozygous cystinuria have been carried out, using liquid chromatography—mass spectrometry with an atmospheric pressure ionization interface system. A kidney cystine stone was also analysed by this system. Very intense quasi-molecular ions ([M + H]⁺) of standard cystine, arginine, lysine and ornithine were observed on mass chromatograms as base peaks. Mass chromatograms of the urine samples from a normal human and from patients with heterozygous and homozygous cystinuria were easily distinguishable. The retention times in the mass chromatogram and mass spectrum of kidney stone cystine was almost the same as that of authentic cystine.     

Difference in 24-Hour Urine Composition between Diabetic and Non-Diabetic Adults without Nephrolithiasis

Background

Diabetic patients are more likely to develop kidney stones than the general population. The underlying mechanisms for this disparity remain to be elucidated. Little is known about the relationship between urine composition and diabetes mellitus in non-stone-forming individuals. We sought to examine the differences in the 24-hour (24-h) urine composition between diabetic and non-diabetic adults who were not stone formers.

Methods

A convenience sample of 538 individuals without a history of nephrolithiasis, gout, hyperparathyroidism, or gastroenteric diseases participated in this study. The 24-h urine profiles of 115 diabetic adults were compared with those of 423 non-diabetic adults. Diabetes was defined by self-reported physician diagnosis or medication use. All participants were non-stone formers confirmed by urinary tract ultrasonography. Participants provided a fasting blood sample and a single 24-h urine collection for stone risk analysis. Student’s t-test was used to compare mean urinary values. Linear regression models were adjusted for age, gender, body mass index, hypertension, fasting serum glucose, serum total cholesterol, estimated creatinine clearance rate and urinary factors.

Results

Univariable analysis showed that the diabetic participants had significantly higher 24-h urine volumes and lower urine calcium and magnesium excretions than non-diabetic participants (all P < 0.05). After multivariate adjustment, no significant differences in 24-h urine composition were observed between diabetic and non-diabetic participants except for a slightly increased 24-h urine volume in diabetic participants (all P > 0.05). The main limitation of this study is that the convenience samples and self-reported data may have been sources of bias.

Conclusion

Our data showed that there were no differences in 24-h urine composition between diabetic and non-diabetic adults who are not stone formers. The reason for it might be the improved glycemic control in diabetic individuals in our study. Therefore, a tighter glycemic control might reduce stone formation in diabetic adults.     

SDS-PAGE-Based Quantitative Assay for Screening of Kidney Stone Disease

Kidney stone disease is a common health problem in industrialised nations. We developed a SDS-PAGE-based method to quantify Tamm Horsfall glycoprotein (THP) for screening of kidney stone disease. Urinary proteins were extracted by using ammonium sulphate precipitation at 0.27 g salt/mL urine. The resulted pellet was dissolved in TSE buffer. Ten microliters of the urinary proteins extract was loaded and separated on 10% SDS-PAGE under reducing condition. THP migrated as single band in SDS-PAGE. The assay reproducibility and repeatability were 4.8% CV and 2.6% CV, respectively. A total of 117 healthy subjects and 58 stone patients were tested using this assay, and a distinct cut-off (P < 0.05) at 5.6 μg/mL THP concentration was used to distinguish stone patients from healthy subjects. The sensitivity and specificity of the method were 92.3% and 83.3%, respectively.     

Advances in the Diagnosis of Human Opisthorchiasis: Development of Opisthorchis viverrini Antigen Detection in Urine

Background

Many strategies to control opisthorchiasis have been employed in Thailand, but not in the other neighbouring countries. Specific control methods include mass drug administration (MDA) and health education to reduce raw fish consumption. These control efforts have greatly shifted the epidemiology of Opisthorchis viverrini (OV) infection over the last decade from presenting as densely concentrated "heavy" infections in single villages to widespread "light" OV infections distributed over wide geographical areas. Currently, the "gold standard" detection method for OV infection is formalin ethyl-acetate concentration technique (FECT), which has limited diagnostic sensitivity and diagnostic specificity for light OV infections, with OV eggs often confused with eggs of minute intestinal flukes (MIFs) in feces. In this study, we developed and evaluated the diagnostic performance of a monoclonal antibody-based enzyme-linked immunosorbent assay for the measurement of OV excretory-secretory (ES) antigens in urine (urine OV-ES assay) for the diagnosis of opisthorchiasis compared to the gold standard detection FECT method.

Methodology

We tested several methods for pre-treating urine samples prior to testing the diagnostic performance of the urine OV-ES assay. Using trichloroacetic acid (TCA) pre-treated urine, we compared detection and quantification of OV infection using the urine OV-ES assay versus FECT in OV-endemic areas in Northeastern Thailand. Receiver operating characteristic (ROC) curves were used to determine the diagnostic sensitivity and specificity of the urine OV-ES assay using TCA pre-treated urine, and to establish diagnostic positivity thresholds. The Positive Predictive Value as well as the likelihood of obtaining a positive test result (LR+) or a negative test result (LR-) were calculated for the established diagnostic positivity threshold. Diagnostic risks (Odds Ratios) were estimated using logistic regression.

Results

When urine samples were pre-treated with TCA prior to use in the urine OV-ES assay, the analytical sensitivity was significantly improved. Using TCA pre-treatment of urine, the urine OV-ES assay had a limit of detection (LoD) of 39 ng/ml compared to the LoD of 52 ng/mL reported for coprological antigen detection methods. Similarly, the urine OV-ES assay correlated significantly with intensity of OV infection as measured by FECT. The urine OV-ES assay was also able to detect 28 individuals as positive from the 63 (44.4%) individuals previously determined to be negative using FECT. The likelihood of a positive diagnosis of OV infection by urine OV-ES assay increased significantly with the intensity of OV infection as determined by FECT. With reference to FECT, the sensitivity and specificity of the urine OV-ES assay was 81% and 70%, respectively.

Conclusion

The detection of OV-infection by the urine OV-ES assay showed much greater diagnostic sensitivity and diagnostic specificity than the current "gold standard" FECT method for the detection and quantification of OV infection. Due to its ease-of-use, and noninvasive sample collection (urine), the urine OV-ES assay offers the potential to revolutionize the diagnosis of liver fluke infection and provide an effective tool for control and elimination of these tumorigenic parasites.     

Surgical Management of Urolithiasis in Patients after Urinary Diversion

Objective

To present our experience in surgical management of urolithiasis in patients after urinary diversion.

Patients and Methods

Twenty patients with urolithiasis after urinary diversion received intervention. Percutaneous nephrolithotomy, percutaneous based antegrade ureteroscopy with semi-rigid or flexible ureteroscope, transurethral reservoir lithotripsy, percutaneous pouch lithotripsy and open operation were performed in 8, 3, 2, 6, and 1 patients, respectively. The operative finding and complications were retrospectively collected and analyzed.

Results

The mean stone size was 4.5±3.1 (range 1.5–11.2) cm. The mean operation time was 82.0±11.5 (range 55–120) min. Eighteen patients were rendered stone free with a clearance of 90%. Complications occurred in 3 patients (15%). Two patients (10%) had postoperative fever greater than 38.5°C, and one patient (5%) suffered urine extravasations from percutaneous tract.

Conclusions

The percutaneous based procedures, including percutaneous nephrolithotomy, antegrade ureteroscopy with semi-rigid ureteroscope or flexible ureteroscope from percutaneous tract, and percutaneous pouch lithotripsy, provides a direct and safe access to the target stones in patients after urinary diversion, and with high stone free rate and minor complications. The surgical management of urolithiasis in patients after urinary diversion requires comprehensive evaluation and individualized consideration depending upon the urinary diversion type, stone location, stone burden, available resource and surgeon experience.     

Molecular signature of renal cell carcinoma by means of a multiplatform metabolomics analysis

Renal cell carcinoma (RCC) is a disease with no specific diagnostic method or treatment. Thus, the evaluation of novel diagnostic tools or treatment possibilities is essential. In this study, a multiplatform untargeted metabolomics analysis of urine was applied to search for a metabolic pattern specific for RCC, which could enable comprehensive assessment of its biochemical background. Thirty patients with diagnosed RCC and 29 healthy volunteers were involved in the first stage of the study. Initially, the utility of the application of the selected approach was checked for RCC with no differentiation for cancer subtypes. In the second stage, this approach was used to study clear cell renal cell carcinoma (ccRCC) in 38 ccRCC patients and 38 healthy volunteers. Three complementary analytical platforms were used: reversed-phase liquid chromatography coupled with time-of-flight mass spectrometry (RP-HPLC-TOF/MS), capillary electrophoresis coupled with time-of-flight mass spectrometry (CE-TOF/MS), and gas chromatography triple quadrupole mass spectrometry (GC-QqQ/MS). As a result of urine sample analyses, two panels of metabolites specific for RCC and ccRCC were selected. Disruptions in amino acid, lipid, purine, and pyrimidine metabolism, the TCA cycle and energetic processes were observed. The most interesting differences were observed for modified nucleosides. This is the first time that the levels of these compounds were found to be changed in RCC and ccRCC patients, providing a framework for further studies. Moreover, the application of the CE-MS technique enabled the determination of statistically significant changes in symmetric dimethylarginine (SDMA) in RCC.     

Low-molecular-weight variants of osteopontin generated by serine proteinases in urine of patients with kidney stones

Osteopontin (OPN) is a multifunctional glycosylated phosphoprotein found in body fluids, including urine, and has been implicated in urinary stone formation. We tested the hypothesis that OPN levels in urine of patients with kidney stones differed from normal individuals. To quantify OPN levels in the urine, we developed an ELISA using a combination of a mouse monoclonal and rabbit polyclonal antibodies raised against a recombinant glutathione-S-transferase-human OPN fusion protein. In a group of 34 patients diagnosed with kidney stones compared with a control group of 23 normal individuals, we found that OPN levels in urine of the patient and control groups ranged from 0.01 to 2.7 μg/ml, with no significant difference in their medians (P > 0.8, Mann-Whitney test). OPN in urine was qualitatively assessed by Western blotting using a biotinylated monoclonal antibody to detect various molecular forms. The urine of most individuals contained OPN species within in the 55- to 66-kDa electrophoretic mobility range. However, a significantly higher proportion of individuals in the patient group (13 of 34) was found to have aberrant urine OPN species (≤ 40 kDa) compared to 2 of 23 for the control group (P < 0.03, x² test). Mixing experiments indicated that urine samples with aberrant OPN contain proteases inhibitable with phenylmethylsulfonyl fluoride. Such proteases could break down normal urine OPN in vitro. Therefore, urine from a high frequency of kidney stone patients contains serine proteases that contribute to proteolytic cleavage of OPN. © 1996 Wiley-Liss, Inc.