Urine kidney injury markers do not increase following gastric bypass: a multi-center cross-sectional study.

INTRODUCTION: To determine if markers of kidney injury correlate with urinary oxalate excretion. If so, such biomarkers might be early predictors of oxalate nephropathy. Gastric bypass surgery for obesity is known to be associated with postoperative hyperoxaluria, which can lead to urolithiasis and kidney damage. MATERIALS AND METHODS: Patients were recruited from four large academic centers > 6 months following completion of gastric bypass surgery. Patients provided a spot urine sample for analysis of three markers of kidney injury: 8-iso-Prostaglandin F2 α, N-acetyl- ß -D-Glucosaminidase, and Neutrophil gelatinase-associated lipocalin. Patients also provided 24 hour urine samples for stone risk analysis. RESULTS: A total of 46 study patients provided samples, the average age was 48.4 +/- 11.3. There were 40 women and 6 men. There was no difference in the level of any of the three inflammatory markers between the study group and the reference range generated from healthy non-hyperoxaluric subjects. Neither oxalate excretion nor supersaturation of calcium oxalate correlated with any of the injury markers. There was no difference noted between those with hyperoxaluria (n = 17) and those with normoxaluria (n = 29) with respect to any of the injury markers. CONCLUSIONS: Though hyperoxaluria was common after bypass surgery, markers of kidney injury were not elevated after surgery. No correlation was found between urine oxalate excretion and any of the injury markers.

Hybrid guidewires: Analysis and comparison of the mechanical properties and safety profiles.

INTRODUCTION: Hybrid guidewires are commonly used in urology due to the advantage of an atraumatic hydrophilic tip, which facilitates negotiating tight areas, coupled with an unkinkable nitinol core shaft that is easy to work over due to the Teflon coating. Our aim was to compare the physical and mechanical properties of five commercially available hybrid guidewires to assess their characteristics and functionality. METHODS: In vitro testing was performed on the following straight-tipped 0.035 inch guidewires: Sensor™ (Boston Scientific), Solo™ Plus (Bard), UltraTrack (Olympus), Rio Tracer™ (Rocamed), and Motion™ (Cook). We evaluated characteristics impacting function (tip flexibility, shaft stiffness, lubricity) and safety (perforation force). Measurements included tip flexibility, lubricity, shaft buckling, and force required to perforate a sheet of aluminum foil. RESULTS: The Motion had the highest tip-bending force (p<0.00001). The Rio Tracer had the stiffest shaft (p<0.00001), followed by the Solo Plus and the Motion, which were significantly stiffer than the Sensor and UltraTrack (p<0.00001). The Solo Plus and UltraTrack had the greatest perforation force (p=0.00023), and the Rio Tracer had the lowest perforation force (p=0.016) when compared to the Sensor. There was no significant difference in frictional force between the five guidewires (p=0.1516). CONCLUSIONS: The Solo Plus and UltraTrack required the greatest force to perforate, which conveys a higher safety margin. The RioTracer is the stiffest guidewire, which may be beneficial for instrument insertion with the tradeoff of having a lower perforation force. The clinical significance of higher tip-bending forces (unfavourable) and higher shaft-bending forces (favourable) deserve further investigation.

Can a Simplified 12-Hour Nighttime Urine Collection Predict Urinary Stone Risk?

OBJECTIVE: To determine if there is correlation between nighttime 12-hour and traditional 24-hour urine collection in regard to chemistry values and the supersaturations of calcium oxalate, calcium phosphate, and uric acid for the metabolic evaluation of nephrolithiasis. MATERIALS AND METHODS: Ninety-five patients were prospectively enrolled from 2013 to 2015. Patients >18 years of age who presented to a tertiary stone clinic and who would normally be counseled for 24-hour urine collection were eligible for the study. Participants completed 24-hour urine collections twice, with each divided into 2 separate 12-hour collections. Day-time collection began after the first morning void and continued for 12 hours. The night collection proceeded for the next 12 hours through the first morning void. RESULTS: Forty-nine 24-hour samples from 35 patients met inclusion criteria and were included in the analysis. Overall, there was strong correlation between the night 12-hour and the 24-hour urine collections with R2 ranging from 0.76 for pH to 0.96 for Citrate. In our analysis of variability, the nighttime 12-hour collection differed from the 24-hour collection by 30% in 1-9 patients (2.0%-18.4%) based on individual chemistry value. Diagnosis of underlying metabolic abnormalities was concordant in 92% of patients. CONCLUSION: A 12-hour nighttime collection has strong correlation with 24-hour urine collection. As such, simplifying the metabolic evaluation to a 12-hour overnight collection may be feasible-improving compliance and decreasing patient burden.

Assessing Transplant Attitudes: Understanding Minority Men's Perspectives on the Multifarious Barriers to Organ Donation.

African Americans comprise 11 % of living organ donors, yet constitute 34 % of the kidney transplant waiting list. There are many barriers to organ donation among minorities that include decreased awareness of transplantation, cultural mistrust of the medical community, financial concerns, and fear of the transplant operation. This study investigates the societal misconceptions and demographic health factors that correlate with minority participation in organ and tissue donation. A 57 question Health and Wellness survey was designed to assess participants' demographic information, medical history, professional background, and opinions regarding organ transplantation. Participants were also asked to complete Quality Metric's Short Form-8 (SF-8) survey to assess physical health, mental health, and quality-of-life. Three hundred twenty-six surveys were administered to minority men. The majority of men were identified as African American, and 55 % were below the age of 40. Though 44 % of participants were willing to donate, only 27 % were registered as organ and tissue donors. Minorities who held misconceptions about organ donation-including the belief that they were too old or unhealthy to donate, for example-had lower general, physical, and mental health scores than those who did not (p = <0.0001). Minorities aware of the shortage for organs or who know a registered donor, an organ recipient, a dialysis patient, or someone on the waiting list were more willing to donate organs. Improving the general, physical, and mental health of minorities, coupled with an active educational outreach program, could result in a greater percentage of minorities registering and willing to be organ and tissue donors.

Comparative analysis of lighted ureteral stents: lumination and tissue effects.

PURPOSE: The objectives of the present study were to compare the luminescence of three types of ureteral illuminated stents and analyze their effects on urothelial histology. MATERIALS AND METHODS: Three types of illuminating ureteral stents; the Cook single illuminating catheter, Cook double illuminating catheter and Stryker illumination system stent were laparoscopically placed in nine female white pigs (50 kg), under general anesthesia. After leaving the stents illuminated for 3 hours, during which time peritoneal insufflation was maintained at 18 mm Hg, the ureter was transected and the intraluminal temperature of the ureter was measured with a digital thermometer. The ureteral tissue was then harvested for histologic evaluation, and the animal was euthanized. RESULTS: Statistical analysis confirmed that Stryker and Cook double illuminated stents were equally efficient in illuminating the ureter (P 0.46) whereas, the Cook single stent was significantly superior (P = 0.000004). There was no significant difference in mean intraluminal temperatures between the Cook single (95.2 degrees F), Cook double (92.3 degrees F), and Stryker (95.1 degrees F) stents. When compared with the intraluminal temperature of control unstented ureters, no significant increase was noted with the Cook single (P = 0.85), Cook double (P = 0.57), or Stryker (P = 0.82). Histologic analysis did not show any evidence of thermal injury to the urothelium or any remarkable alteration in the ureteral mucosa. CONCLUSION: The Cook single illuminated stent presented the highest luminescence. All three devices did not cause any remarkable injury to the urothelium after 3 hours of exposure.