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Concept: Kidney stone

165

Kidney stones (nephrolithiasis) are a widespread disease. Thus, blocking stone formation and finding new therapeutic methods is an important area of study. Diosmin (a major component of the bile) is known to have antioxidant as well as renoprotective effects. The present investigation aimed to evaluate the effect of diosmin on renal tissue protection in rats with ethylene glycol-induced nephrolithiasis.

Concepts: Kidney, Nephrology, Vitamin D, Urinary bladder, Vitamin C, Uric acid, Kidney stone, Oxalate

164

Extracorporeal shock wave lithotripsy (ESWL) is a first-line treatment for pediatric urinary stone disease. We aimed to determine the factors affecting the outcome of ESWL for unilateral urinary stones in children.

Concepts: Urology, Kidney stone, Lithotriptor

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Crystalline materials are crucial to the function of living organisms, in the shells of molluscs, the matrix of bone, the teeth of sea urchins, and the exoskeletons of coccoliths. However, pathological biomineralization can be an undesirable crystallization process associated with human diseases. The crystal growth of biogenic, natural and synthetic materials may be regulated by the action of modifiers, most commonly inhibitors, which range from small ions and molecules to large macromolecules. Inhibitors adsorb on crystal surfaces and impede the addition of solute, thereby reducing the rate of growth. Complex inhibitor-crystal interactions in biomineralization are often not well elucidated. Here we show that two molecular inhibitors of calcium oxalate monohydrate crystallization-citrate and hydroxycitrate-exhibit a mechanism that differs from classical theory in that inhibitor adsorption on crystal surfaces induces dissolution of the crystal under specific conditions rather than a reduced rate of crystal growth. This phenomenon occurs even in supersaturated solutions where inhibitor concentration is three orders of magnitude less than that of the solute. The results of bulk crystallization, in situ atomic force microscopy, and density functional theory studies are qualitatively consistent with a hypothesis that inhibitor-crystal interactions impart localized strain to the crystal lattice and that oxalate and calcium ions are released into solution to alleviate this strain. Calcium oxalate monohydrate is the principal component of human kidney stones and citrate is an often-used therapy, but hydroxycitrate is not. For hydroxycitrate to function as a kidney stone treatment, it must be excreted in urine. We report that hydroxycitrate ingested by non-stone-forming humans at an often-recommended dose leads to substantial urinary excretion. In vitro assays using human urine reveal that the molecular modifier hydroxycitrate is as effective an inhibitor of nucleation of calcium oxalate monohydrate nucleation as is citrate. Our findings support exploration of the clinical potential of hydroxycitrate as an alternative treatment to citrate for kidney stones.

Concepts: Kidney, Crystal, Chemistry, Urinary bladder, Crystallization, Kidney stone, Nucleation, Crystal growth

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Safe and successful puncture of the kidney’s collecting system is essential for acute therapy of hydronephrosis or as part of percutaneous nephrolithotomy. The procedure is technically challenging and might lead to major complications. We describe the feasibility of a laser guidance system and three-dimensional puncture planning in the endourological operation room.

Concepts: Kidney, Nephrology, In vivo, Renal pelvis, Kidney stone, Hydronephrosis, Guidance system, Laser guidance

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Uric acid, the major component in many kinds of kidney stones, as well as its sodium, ammonium, calcium, and barium salts were successfully prepared as uniform dispersions by precipitation in basic aqueous solutions. The effects of the reactant concentrations, pH, and the stabilizers were evaluated in detail. Except for the platelets of the pure acid, all prepared compounds appeared as needles or their aggregates. The electron micrographs showed that kidney stones consisted of such aggregates although less regular in size and morphology. All prepared urate salts had a 1:1 cation/uric acid ratio, regardless of the valence of the cation. The electrokinetic measurements showed all these particles to have negative ζ-potentials over the pH range 3-9. The precipitated salt particles were chemically and morphologically unstable at low pH values by decomposing into ill-defined aggregates of the pure uric acid.

Concepts: Ammonia, Water, Chemistry, Nitrogen, PH, Sodium, Uric acid, Kidney stone

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The treatment of kidney stone disease has changed dramatically over the past 30 years. This change is due in large part to the arrival of extracorporeal shock wave lithotripsy (ESWL). ESWL along with the advances in ureteroscopic and percutaneous techniques has led to the virtual extinction of open surgical treatments for kidney stone disease. Much research has gone into understanding how ESWL can be made more efficient and safe. This article discusses the parameters that can be used to optimize ESWL outcomes as well as the new concepts that are affecting the efficacy and efficiency of ESWL.

Concepts: Urology, English-language films, Change, Kidney stone, Shock wave, Lithotriptor, Extracorporeal shock wave lithotripsy, Shockwave

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OBJECTIVE: To examine the association between cardioprotective use of low-dose aspirin and the risk of recurrent gout attacks among gout patients. METHODS: We conducted an online case-crossover study of individuals with gout over 1 year. The following information was obtained during gout attacks: the onset dates, symptoms and signs, medications, and exposure to potential risk factors, including daily aspirin use and dosage, during the 2-day hazard period prior to the gout attacks. The same exposure information was also obtained over 2-day control periods. RESULTS: Of the 724 participants analysed, 40.5% took aspirin ≤325 mg/day during either a hazard or a control period. Compared with no aspirin use, the adjusted OR of gout attacks increased by 81% (OR=1.81, 95% CI 1.30 to 2.51) for ≤325 mg/day of aspirin use on two consecutive days. The corresponding ORs were stronger with lower doses (eg, OR=1.91 for ≤100 mg, 95% CI 1.32 to 2.85). These associations persisted across subgroups by sex, age, body mass index categories and renal insufficiency status. Concomitant use of allopurinol nullified the detrimental effect of aspirin. CONCLUSIONS: Our findings suggest that the use of low-dose aspirin on two consecutive days is associated with an increased risk of recurrent gout attacks. Recommended serum urate monitoring with concomitant use and dose adjustment of a urate-lowering therapy among patients with gout may be especially important to help avoid the risk of gout attacks associated with low-dose aspirin.

Concepts: Risk, Obesity, Body mass index, Dose, Gout, Allopurinol, Uric acid, Kidney stone

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PURPOSE: We report our experience with ureteroscopy, percutaneous nephrolithotomy (PCNL), and shock wave lithotripsy (SWL) for the treatment of symptomatic stone disease in patients with ileal conduit urinary diversions. MATERIALS AND METHODS: Retrospective chart review of all patients treated with cystectomy and ileal conduit urinary diversion from 1982 to June of 2010 who subsequently developed urolithiasis was performed. RESULTS: We identified 77 patients who developed urolithiasis requiring surgical intervention after ileal conduit urinary diversion. Average treatment age was 62.5 years (30-82). Mean follow-up was 7.1 years (0.1-24.3). Primary mode of therapy was percutaneous nephrolithotomy (PCNL) in 48 (62.3%), extracorporeal shock wave lithotripsy (SWL) in 20 (26.0%) and ureteroscopy in 9 (11.6%), patients. Average stone size was larger for PCNL (2.1 cm) compared to ureteroscopy (0.9 cm) or SWL (1.0 cm), (p<0.0001). Total complication rates were similar between groups: 29% PCNL, 30% SWL, and 33% ureteroscopy, (p=0.9). Stone-free status was higher in the PCNL (83.3%) cohort compared to the ureteroscopy (33.3%) or SWL (30%), (p<0.0001). The retreatment rate was not significantly different between groups with 66.7% of the ureteroscopy group requiring subsequent procedures compared to 29.2% of PCNL and 45% of SWL (p=0.08). Change in mean preoperative and current calculated glomerular filtration rate was not significantly different amongst the three treatment groups. CONCLUSIONS: Treatment of urolithiasis in patients with urinary diversion is associated with high retreatment and complication rates. PCNL achieves better stone-free outcomes than ureteroscopy or SWL; however, there was no difference in ancillary procedures or complication rates between the three treatment modalities.

Concepts: Medical terms, Mode, Surgery, Urology, Minimally invasive, Kidney stone, Urinary diversion, Ileal conduit urinary diversion

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The first indwelling ureteral splint was described in 1967. A ureteral stent can cause unpleasant side effects, such as urinary frequency, urgency, incontinence, hematuria, bladder pain and flank pain, which have a negative impact on a patient’s quality of life. It is necessary to minimize the amount of material in the bladder in order to decrease stent-related symptoms. This study investigated the stent-related symptoms after changing from a double pigtail to a loop-type ureteral stent in the same patient group. This study followed 25 patients who underwent ureteral stent exchange from double pigtail to loop-type ureteral stent between September 2009 and February 2010. Ureteral stents were exchanged using topical, conscious sedation and general anesthesia for the various procedures including stent exchange, before/after shock wave lithotripsy and before/after ureteroscopy. The stent length was selected to be the same as whole ureteral length and the caliber based on the previous stent. A self-administered stent-related symptom questionnaire was used to assess stent-related symptoms in comparison to the previous double-pigtail stents. A total of 25 patients with a median age of 56.5 years underwent ureteral stent exchange. All patients had stone disease except two patients who had ureteral stricture. Almost all of stent-related symptoms without nocturia showed a significantly lower score with the loop-type ureteral stent than in double-pigtail stent. None of the patients experienced urinary tract infection either before or after undergoing ureteral stent exchange. Changing to loop-type ureteral stent significantly decreased ureteral stent-related symptoms.

Concepts: Kidney, Urine, Urology, Urinary bladder, Urinary system, Ureter, Anesthesia, Kidney stone

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Abstract Objectives: To examine the clinical outcomes and cost-effectiveness of endourologic procedures performed in the office using standard fluoroscopy and topical anesthesia. Methods: We performed a retrospective review of all patients who underwent primary ureteral stent placement, ureteral stent exchange, or ureteral catheterization with retrograde pyeolography or Bacillus Calmette-Guerin (BCG) instillation under fluoroscopic guidance in the office. For an evaluation of potential time savings, we compared this to a cohort of similar procedures performed in the operating room during the same time period. Results: Procedures were attempted in 65 renal units in 38 patients (13 male, 25 female) with a mean age of 62.2 years (range 29.1-95.4 years). Primary ureteral stent placement was successful in 23/24 (95.8%) renal units. Ureteral stent exchange was successful in 19/22 (86.4%) renal units. Ureteral catheterization with retrograde pyelography or BCG instillation was successful in 19/19 (100%) renal units. The total cost savings for the 38 patients in this study, including excess cost from failure in the office, was approximately $91,496, with an average cost savings of $1,551 per procedure. Office-based procedures were associated with a nearly three-fold reduction in total hospital time as a result of reduced periprocedure waiting times. Conclusions: Ureteral stent placement, ureteral stent exchange, and ureteral catheterization can be performed safely and effectively in the office in both men and women. This avoids general anesthesia and provides significant savings of time and cost for both patients and the health care system.

Concepts: Health economics, Clinical trial, Costs, Anesthesia, Radiology, Cost-effectiveness analysis, Kidney stone, Periodization