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Introduction: Obesity is associated with kidney stone disease, but it is unknown whether this association differs by SES. This study assessed the extent to which obesity and neighborhood characteristics jointly contribute to urinary risk factors for kidney stone disease., Methods: This was a retrospective analysis of adult patients with kidney stone disease evaluated with 24-hour urine collection (2001-2020). Neighborhood-level socioeconomic data were obtained for a principal component analysis, which identified 3 linearly independent factors. Associations between these factors and 24-hour urine measurements were assessed using linear regression as well as groupings of 24-hour urine results using multivariable logistic regression. Finally, multiplicative interactions were assessed testing effect modification by obesity, and analyses stratified by obesity were performed. Analyses were performed in 2021., Results: In total, 1,264 patients met the study criteria. Factors retained on principal component analysis represented SES, family structure, and housing characteristics. On linear regression, there was a significant inverse correlation between SES and 24-hour urine sodium (p=0.0002). On multivariable logistic regression, obesity was associated with increased odds of multiple stone risk factors (OR=1.61; 95% CI=1.15, 2.26) and multiple dietary factors (OR=1.33; 95% CI=1.06, 1.67). No significant and consistent multiplicative interactions were observed between obesity and quartiles of neighborhood SES, family structure, or housing characteristics., Conclusions: Obesity was associated with the presence of multiple stone risk factors and multiple dietary factors; however, the strength and magnitude of these associations did not vary significantly by neighborhood SES, family structure, and housing characteristics., (Copyright © 2022 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Robotic pyelolithotomy (RPL) and robotic nephrolithotomy (RNL) may be utilized for treating kidney stones as an alternative to percutaneous nephrolithotomy or flexible ureteroscopy., Objective: To describe the techniques of RPL and RNL, and present multi-center outcome data for patients undergoing these procedures., Design, Setting, and Participants: This study was a retrospective analysis of 27 patients undergoing RPL and RNL at five tertiary academic institutions between 2008 and 2014., Surgical Procedure: RPL and RNL without use of renal ischemia., Measurements: We assessed stone clearance by visual assessment and postoperative imaging. We also examined other factors, including complications (Clavien grade), estimated blood loss, operative time, and length of stay., Results and Limitations: Twenty-seven patients underwent 28 procedures for a mean renal stone size of 2.74cm (standard deviation: 1.4, range: 0.8-5.8). The mean stone volume was 10.2cm 3 . RPL accounted for 26 of these procedures. RNL was performed in one patient, while another underwent combined RPL-RNL. Indications included failed previous endourological management (13), staghorn calculi (five), gas containing stone (one), calyceal diverticulum (one), complex urinary tract reconstruction (two), and patient preference (four). The mean patient age was 35.6 yr and mean body mass index was 25.5kg/m 2 . Mean operative time/console times were 182min and 128min, respectively. The mean estimated blood loss was 38ml. The mean length of stay was 1.7 d. There was no significant change in preoperative and postoperative serum creatinine levels. The overall complication rate was 18.5% (Clavien 1=3.7%; 2=7.4%; 3b=7.4%). The complete stone-free rate was 96%., Conclusions: RPL and RNL are safe and reasonable options for removing renal stones in select patients. In particular, RPL allows the removal of stones without transgressing the parenchyma, reducing potential bleeding and nephron loss., Patient Summary: The robotic approach allows for complete removal of the renal stone without fragmentation, thereby maximizing chances for complete stone clearance in one procedure., (Published by Elsevier B.V.)

Objective: To determine whether glyoxal can be converted to oxalate in human erythrocytes. Glyoxal synthesis is elevated in diabetes, cardiovascular disease, and other diseases with significant oxidative stress. Erythrocytes are a good model system for such studies as they lack intracellular organelles and have a simplified metabolism., Materials and Methods: Erythrocytes were isolated from healthy volunteers and incubated with varying concentrations of glyoxal for different amounts of time. Metabolic inhibitors were used to help characterize metabolic steps. The conversion of glyoxal to glycolate and oxalate in the incubation medium was determined by chromatographic techniques., Results: The bulk of the glyoxal was converted to glycolate, but ~1% was converted to oxalate. Inclusion of the pro-oxidant, menadione, in the medium increased oxalate synthesis, and the inclusion of disulfiram, an inhibitor of aldehyde dehydrogenase activity, decreased oxalate synthesis., Conclusion: The glyoxalase system, which utilizes glutathione as a cofactor, converts the majority of the glyoxal taken up by erythrocytes to glycolate, but a small portion is converted to oxalate. A reduction in intracellular glutathione increases oxalate synthesis and a decrease in aldehyde dehydrogenase activity lowers oxalate synthesis and suggests that glyoxylate is an intermediate. Thus, oxidative stress in tissues could potentially increase oxalate synthesis., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: To determine if this trend toward calcium phosphate stone formation exists in children., Methods: This is a retrospective study of medical records of 179 children managed at our medical center from 1992-2010 for whom stone analysis and other pertinent laboratory data were available. A comparison of patients managed from 1992-2000 (P1) and 2001-2010 (P2) was undertaken. Statistical analysis included nonparametric tests., Results: There were no significant differences in the mean age of the 2 cohorts. During both periods, boys comprised a significantly higher proportion during the first decade of life, whereas girls comprised a significantly higher proportion during the second decade. A higher percentage of patients had calcium oxalate (CaOx) stones in P1 compared to P2 (60% vs 47%, P = .0019). There was a significant increase in the percentage of patients having calcium phosphate stones in P2 compared to P1 (27% vs 18.5%, P = .008). Twenty-seven patients had recurrent stones. A comparison of the compositions of the first and last stones of patients within this group demonstrated an increasing proportion of brushite stones (3.7% vs 11.1%, P = .04). Twenty-four hour urine testing results were similar for those with CaOx and calcium phosphate stones., Conclusion: An increasing proportion of children have calcium phosphate calculi. Brushite stones are more prevalent in children with recurrent stone events. The impetus of these shifts is not readily apparent., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objective: To determine whether the ratio of dietary calcium and oxalate consumption at mealtime affects gastrointestinal oxalate absorption and urinary oxalate excretion., Methods: A study was conducted with 10 non-stone-forming adults placed on controlled diets with daily calcium and oxalate contents of 1000 and 750 mg, respectively. Subjects consumed a balanced calcium/oxalate ratio diet for 1 week, observed a minimum 1-week washout period, and subsequently consumed an imbalanced calcium/oxalate ratio diet for one week. Urine specimens were collected on the last 4 days of each diet. Outcome measures included urinary creatinine, calcium, and oxalate as well as the Tiselius index for assessing urinary calcium oxalate supersaturation., Results: Total daily calcium excretion, oxalate excretion, and Tiselius index were similar between balanced and imbalanced dietary phases. There were significant differences in calcium excretion (mg/g creatinine) between balanced and imbalanced diets in the 1-6 PM (83.1 vs 110.2, P <.04), 6-11 PM (71.3 vs 107.2, P <.02), and 11 PM-8 AM collections (55.0 vs 41.8, P <.02). There was significantly higher oxalate excretion on the balanced diet in the 1-6 pm time period (28.1 vs 16.7, P <.01). There were no differences in the Tiselius index in these collections., Conclusion: These results demonstrate that the sequence of ingesting relatively large amounts of oxalate does not significantly affect calcium oxalate stone risk if the recommended daily quantity of dietary calcium is consumed., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: To determine the sensitivity of 4 strains of Oxalobacter formigenes (Oxf) found in humans--HC1, Va3, CC13, and OxK--to varying concentrations of commonly prescribed antibiotics. Oxf gut colonization has been associated with a decreased risk of forming recurrent calcium oxalate kidney stones., Methods: For each strain and each antibiotic concentration, 100 μL of an overnight culture and 100 μL of the appropriate antibiotic were added to a 7-mL vial of oxalate culture medium containing 20 mM oxalate. On the fourth day, vials were visually examined for growth, and a calcium oxalate precipitation test was performed to determine whether Oxf grew in the presence of the antibiotic., Results: All 4 Oxf strains were resistant to amoxicillin, amoxicillin/clavulanate, ceftriaxone, cephalexin, and vancomycin, and they were all sensitive to azithromycin, ciprofloxacin, clarithromycin, clindamycin, doxycycline, gentamicin, levofloxacin, metronidazole, and tetracycline. One strain, CC13, was resistant to nitrofurantoin, and the others were sensitive. Differences in minimum inhibitory concentration between strains were demonstrated., Conclusion: Four human strains of Oxf are sensitive to a number of antibiotics commonly used in clinical practice; however, minimum inhibitory concentrations differ between strains., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objectives: To better understand intestinal oxalate transport by correlating oxalate and sucralose absorption in idiopathic calcium oxalate stone formers. Oxalate has been hypothesized to undergo absorption in the large and small intestine by both paracellular and transepithelial transport. Sucralose is a chlorinated sugar that is absorbed by paracellular mechanisms., Methods: Idiopathic calcium oxalate stone formers were recruited to provide urine specimens on both a self-selected diet and after a meal containing 90 mg of (13)C(2-)oxalate and 5 g of sucralose, and a stool sample for determination of Oxalobacter formigenes colonization. The 24-hour urine collections were fractionated into the first 6 hours and the subsequent 18 hours. Sucralose and oxalate excretion were measured during these periods and used to estimate absorption., Results: Thirty-eight subjects were evaluated. The majority of both the (13)C(2-)oxalate and sucralose absorption occurred within the 0-6-hour collection. The (13)C(2-)oxalate and sucralose absorptions were significantly correlated at the 0-6 hour, the 6-24 hour, and the total 24-hour time periods (P <.04). All 5 oxalate hyperabsorbers(>15% absorption) also absorbed significantly more sucralose during the 0-6 hour and whole 24-hour time points (P <.04). Oxalobacter formigenes colonization did not significantly alter oxalate absorption., Conclusions: The results suggest that most oxalate is absorbed in the proximal portion of the gastrointestinal tract and that paracellular transport is involved. Augmented paracellular transport, as evidenced by increased sucralose absorption, may also influence oxalate absorption., (Copyright © 2011 Elsevier Inc. All rights reserved.)