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Urol Res [journal]
- Biomolecular mechanism of urinary stone formation involving osteopontin. [Journal Article, Research Support, Non-U.S. Gov't]
- Urol Res 2012 Dec; 40(6):623-37.
Urinary stones consist of two phases-an inorganic (mineral) phase and an organic (matrix) phase. Studies on the organic components of kidney stones have been undertaken later than those on the inorganic components. After osteopontin was identified as one of the matrix components, the biomolecular mechanism of urinary stone formation became clearer. It also triggered the development of new preventive treatments. Osteopontin expression is sporadically observed in normal distal tubular cells and is markedly increased in stone-forming kidneys. Calcium oxalate crystals adhering to renal tubular cells are incorporated into cells by the involvement of osteopontin. Stimulation of crystal-cell adhesion impairs the opening of mitochondrial permeability transition pores (mPTP) in tubular cells and produces oxidative stress, apoptosis, and osteopontin expression. Macrophages phagocytose and digest a small amount of crystals, but many crystals aggregate into a mass containing osteopontin and epithelial cell debris and are excreted into the renal tubular lumen, becoming nuclei of urinary stones. This biomolecular mechanism is similar to atherosclerotic calcification. Based on these findings, new preventive treatments have been developed. Dietary control such as low-cholesterol intake and the ingestion of antioxidative foods and vegetables have successfully reduced the 5-year recurrence rate. Osteopontin antibodies and cyclosporine A, which blocks the opening of mPTP, have markedly inhibited the expression of osteopontin and urinary stone formation in animal models.
- Renal tubular epithelial cell injury, apoptosis and inflammation are involved in melamine-related kidney stone formation. [Journal Article, Research Support, Non-U.S. Gov't]
- Urol Res 2012 Dec; 40(6):717-23.
The objective of this study is to understand pathogenesis of melamine-related kidney stone formation. We investigated the characterization of renal tubular cell under exposure to a mixture of melamine and cyanuric acid in vivo. Male Sprague-Dawley rats were separated into two experimental groups. Treatment group was administered daily with a standard commercial diet mixing with melamine and cyanuric acid, and control group was given a normal diet. Rat kidney specimens were stained with hematoxylin/eosin and the crystals were examined using a polarizing microscope. Renal tubular epithelial cells were observed by transmission electron microscopy. Semiquantitative RT-PCR assay was performed to determine monocyte chemoattractant protein-1 (MCP-1) mRNA expression, a protein in response to various proinflammatory stimuli. Apoptotic cells were examined by TUNEL assay. Melamine-associated crystals formed in glomerulus and wide renal tubule segment including proximal convoluted renal tubules, distal convoluted renal tubules, the limb loops of Henle and medullary collecting ducts in the cortex and medulla. Light microscopy results showed that the crystals lead to tubular lumen dilatation and tubular epithelial cell necrosis. It was observed that nucleus of renal tubular epithelial cells became irregular outlines and condensed, lysosomal-related structures increased, and integrity of renal tubule was deficient under electron microscopy. Apoptotic cells were noted widely in cortex and medulla. MCP-1 mRNA expression was significantly increased in the melamine and cyanuric acid-administrated group. Renal tubular epithelial cell injury, apoptosis and inflammation are involved in melamine-related kidney stone formation. Our findings are important for understanding pathogenesis of melamine-related kidney stone formation and estimating its clinical prognosis.
- Role of 1 week of antibiotic prophylaxis before percutaneous nephrolithotomy. [Comment, Letter]
- Urol Res 2012 Dec; 40(6):805-6.
- What is the value of bone remodeling markers in patients with calcium stones? [Letter]
- Urol Res 2012 Dec; 40(6):803.
- Spontaneous stone passage: is it Ammi visnaga effect? [Letter]
- Urol Res 2012 Dec; 40(6):799-800.
Ammi visnaga was used in Ancient Egypt as an herbal remedy for renal colic. "Khellin", a chemical obtained from Ammi visnaga, was used as a smooth muscle relaxant and has been thought to have pleiotropic effects on urolithiasis. We report a case with multiple ureteral stone passages possibly as a result of medication with an herb preparation, Khellin.
- The technical details of treatment of kidney stone in children. [Letter]
- Urol Res 2012 Dec; 40(6):801-2.
- Flexible ureterorenoscopic management of upper tract pathologies. [Journal Article]
- Urol Res 2012 Dec; 40(6):639-46.
The last decade flexible ureteroscopy has progressed from an awkward diagnostic procedure with limited visualization to a precise surgical intervention allowing access to the entire collecting system. In this review, we present the current status and future perspectives of the ureterorenoscopic management of urolithiasis and non-stone-related upper tract pathologies.
- Effect of SWL on renal hemodynamics: could a change in renal artery contraction-relaxation responses be the cause? [Journal Article]
- Urol Res 2012 Dec; 40(6):775-80.
The aim of this study was to reveal the effect of shock wave lithotripsy (SWL) on renal artery contraction-relaxation responses and the relation of this effect with renal hemodynamics. Twenty-four rabbits are divided into six different groups. The first two groups evaluated as the control groups. After isolating the kidneys, we applied phenylephrine (Ph) and acetylcholine (Ach) in the first group and sodium nitroprusside (SNP) and histamine (H) in the second group. In the third, fourth, fifth and sixth groups, 14.5 kV shock wave (SW) was focused on the left kidneys. We adjusted the number of shocks to a total of 500, 1,500, and 3,000 SW, in the third, fourth and fifth groups, respectively. After isolating the kidneys, Ph, Ach was given in groups 3, 4 and 5. In the sixth group, to get the SNP and the H responses, 3,000 shocks modality was utilized. Marked contractile responses were obtained by phenylephrine in the control group. In kidneys that were exposed to 500 shocks SWL procedures, a decrease in contractile responses and hence, in perfusion pressures in different concentrations of phenylephrine was noted. However, a notable change in relaxation responses occurred after 3,000-shock applications. No difference in relaxation responses to nitroprusside, a direct vasodilating agent, was observed in any group, compared to the control group. Another cause of deterioration of renal hemodynamics after SWL can be attributed to the reduction in renal artery contraction-relaxation responses that result in the vascular smooth muscle and endothelial damage.
- Naftopidil and tolterodine in the medical expulsive therapy for intramural ureteral stones: a prospective randomized study. [Journal Article]
- Urol Res 2012 Dec; 40(6):757-62.
We performed a randomized, prospective study to assess the possible role of combined naftopidil and tolterodine for facilitating the spontaneous expulsion of intramural ureteral stones. A total of 76 patients with intramural ureter stones were included in the study from December 2007 to February 2011. Patients were randomized to one of three treatment groups. Group A patients received naftopidil 25 mg/day, group B patients received naftopidil 25 mg/day plus tolterodine 2 mg (twice a day), and group C patients received tolterodine 2 mg (twice a day). Both groups were followed up for 2 weeks. The stone expulsion rate and time and the number of pain episodes were obtained. Subjects rated the urgency associated with each micturition using the Urinary Sensation Scale (USS). Pain descriptions were recorded by the patients using the visual analog scale (VAS). A significant difference was shown for the expulsion rate between the group C and the other two groups (P < 0.001 by log rank test). In groups A, B and C, the mean number of pain episodes was 2.25 ± 0.90, 1.38 ± 1.37 and 1.54 ± 1.18, respectively. The USS score for groups A, B and C at 3 days was 2.32 ± 0.55, 1.4 ± 0.58 and 1.34 ± 0.49, respectively. It was 1.75 ± 0.44, 1.2 ± 0.41 and 1.22 ± 0.42, respectively, at 7 days. On the other hand, a statistically significant difference was found between groups A and B, and groups A and C in relation to the visual analog scale score on days 3 and 7, respectively. Treatment with naftopidil and tolterodine appears to be beneficial in intramural ureteral stones clearance, particularly in the intramural ureter with symptoms of vesical irritability.