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103The significance of “minor” components of calcium renal stones
101
102
VITAMIN D R E C E P T O R GENE BSMI AND TAQ1 P O L Y M O R P H I S M S IN T U R K I S H PATIENTS W I T H URINARY T R A C T STONES
R E N A L T U B U L A R A L T E R A R A T I O N BY CRYSTALLURIA INITIATES C A L C I U M OXALATE STONE F O R M A T I O N - AN E X P E R I M E N T A L STUDY BY MEANS OF M D C K - C E L L S
Grren M.R?, Atac F.B. 2, Tekin M.I. 1, Dirim A. 1, Egilmez T. 3, Verdi U. 2, Ozkardes H. IBaskent University, Urology, Ankara, Turkey, 2Baskent University, Medical Biology and Genetics, Ankara, Turkey, 3Baskent University, Urology, Adana, Turkey I N T R O D U C T I O N & OBJECTIVES" Polymorphisms of vitamin D receptor (VDR) gene has recently been reported to be associated with calcium metabolism disorders. We aimed to investigate the correlation between urinary tract stones and VDR gene polymorphisms, namely BsmI and TaqL M A T E R I A L & M E T H O D S : Between May 2003 and June 2004, 72 patients (26 females, 46 males) with a mean age of 49 years (range; 18-78) who have urinary tract stones were evaluated for VDR gene polymorphisms. Patients with urinary tract infection; hyperparathyroidism; gout diathesis; renal tubular acidosis; renal failure; chronic diarrhoeal states; and those receiving thiazide diuretics, angiotensin-converting enzyme (ACE)-inhibitors, glucocorticoids or estrogens were excluded. Results were compared to those obtained from 72 healthy individuals with a mean age of 53 years (range; 21-78). VDR gene BsmI and TaqI polymorphisms were determined by polymerase chain reaction (PCR) -restriction fragment length polymorphism (RFLP).
Lahme S. 1, Feil G. 2, Strohmaier W. 3, Bichler Kfl, Stenzl A. 2 1St. Trudpert Hospital, Urology, Pforzheim, Germany, 2University of Tuebingen, Urology, Tuebingen, Germany, 3Klinikum Coburg, Urology, Coburg, Germany I N T R O D U C T I O N & OBJECTIVES: The mechanism behind stone formation is still unclear. Physicochemical properties alone cannot explain why urinary stones form. Detection of cellular enzymes in the urine, papillary calcifications and the short transit time of the urine in the renal tubule are factors that do not permit crystals to grow to calculi and thus speak for an involvement of the renal tubule in the process of stone formation. In addition animal experiments with a rat model suggest that alteration of the distal renal tubular cell triggers stone formation. M A T E R I A L & METHODS: Experiments were done by means of a cell culture model (Madin Darby Canine Kidney cells, MDCK- cells). MDCK- cells were cultured in DMEM with 10 % fetal calf serum (FCS) at 37 degrees Celsius und 5 % CO 2. 100 U/ml penicillin, 100 ~tg/ml streptomycin and 2 m M glutamine were added. Subculturing was performed with 0.025 % trypsin. Cultures were prepared by plating 2.5 x 104 cells/well in 96-well dishes. Calcium oxalate crystals (COC) with a diameter of 2 lxm were added and cytotoxic effect was determined by photometrical measurement of Lactate-Dehydrogenase (LDH) in cell supematant. In the study group parathormone (PH), vitamin D 3 (VD), allopurinol, oxipurinol and selenium were added.
RESULTS: There were no statistically significant differences in the BsmI and Taq I genotype distribution of VDR gene in control and patient groups. Moreover, a subgroup of 28 cases out of 72 patients were evaluated for hypercalciuria and the results points out that VDR gene BsmI and Taq I polymorphisms are not associated in the development of hypercaleiuria in our population.
RESULTS: PH and VD had no altering effect on the tubule in contrast to the experimental findings from the animal model. On the other hand, a reproducible tubular cell impairment was induced with COC, expressed as a 27%-rise in the LDH concentration in the cell supernatant. Allopurinol, oxipminaol and selenium inhibited this effect. Oxalate concentration and pH did not influence renal tubular alteration by COC.
CONCLUSIONS: Our preliminary data may indicate that BsmI and TaqI polymorphisms of the VDR gene have no impact on urinary tract stone disease. This study is ongoing with the inclusion ofApaI polymorphism and subgroups of hypercalciuria, stone types and hypocitraturia.
CONCLUSIONS: The observations show that COC in the urine can directly damage the renal tubule. These findings indicate that an interaction between COC and the renal tubular cell is significant for urinary stone formation. This effect was inhibited by allopurinol and selenium, a fact that may speak for the use of both substances in the scope of stone metaphylaxis.
103
104
THE SIGNIFICANCE OF " M I N O R " C O M P O N E N T S OF C A L C I U M R E N A L STONES
D Y N A M I C M E C H A N I C A L ANALYSIS OF D I F F E R E N T TYPES OF E N C R U S T E D P O L Y M E R I C U R I N A R Y STENTS BY M A T E R I A L DEGRADATION ASSESSMENT
Trinchieri A. 1 Lizzano R.2, Castelnuovo C.2, Zanetti G.2 ~Ospedale di Lecco, Urology Unit, Lecco, Italy, 2IRCCS Ospedale Maggiore di Milano, Urology Unit, Milano, Italy
Liatsikos E. 1 Mouzakis D?, Bouropoulos N ) , Bithelis G. 3, Barbalias G.1
INTRODUCTION & OBJECTIVES: In calcium renal stones, calcium oxalate (CAOX) and calcium phosphate (CAP) in various crystal forms and states of hydratation can be identified. Calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) are the commonest constituents of calcium stones. CAOX stones may be apparently pure or mixed, usually with CAP or sometimes with uric acid (UA) or ammonium urate. The aim of this study was to compare the clinical and urinary patterns of patients forming calcium stones of different composition.
1University of Patras, School of Medicine, Patras, Greece, 2University of Patras, Department of Material Science, Patras, Greece, 3University Hospital of Patras, Urology, Patras, Greece
MATERIAL & METHODS: The stones of 84 consecutive calcium renal stone formers were examined by infrared spectroscopy. In each patient a blood sample was drawn and analysed for serum biochemistry and a 242hour urine sample was collected and analysed for calcium, phosphate, oxalate, citrate and other electrolytes. We classified 49 patients as calcium oxalate monnhydrate (COM) stone formers, 32 as calcium oxalate dihydrate (COD) stone formers and 3 as apatite stone formers according to the main component of their stones. RESULTS: Mean daily urinary calcium (210+/106 vs 334+/-134 mg/day) and urinary saturation with respect to CAOX (4.85+/-3.10 vs. 7.35+/-3.61) were significantly lower in patients with COM than in those with COD stones (p < 0.000). Patients with CAOX stones containing an UA component (equal or less than 10%) presented with higher saturation (1.83+/-1.31 vs. 1.17+/-0.93, p<0.012) with respect to UA in their urine (and lower with respect to CAOX and CAP, respectively p<0.024 and p<0.003) in comparison with patients without UA component in the stone. Patients with CAOX stones with a CAP component (equal or more than 15%) showed higher (2.03+/-2.52 vs. 1.68+/-2.05, p<0.0016) urinary saturation levels with respect to CAP (and lower with respect to UA, p<0.009) compared with patients forming stones without CAP or with a low CAP component. Patients with calcium stones mixed with UA showed significantly lower urinary pH (5.35+/-0.50 vs. 5.70+/-0.45, p<0.002) and calcium (194+/-i24 vs. 288+/-121 mg/day, p<0.000) and patients with CAP > 15% higher urinary pH (5.86+/-0.34 vs. 5.63+/-0.46, p<0.004) and calcium (342+/-141 vs. 275+/-117 mg/day, p<0.000). CONCLUSIONS: In the evaluation of the individual stone patient an accurate analysis of the stone showing its exact composition and the eventual presence of minor components of the stone is mandatory in order to plan the correct prophylactic treatment. Patients with "calcium stones" could deserve a different approach in relation to the form and hydratation of the calcium crystals in their stones and to the presence of "minor" crystalline components that could have acted as epitaxial factors.
European Urology Supplements 4 (2005) No. 3, pp. 28
I N T R O D U C T I O N & OBJECTIVES: The use of polymeric urinary stents is widespread in many endo-urethral and endo-ureteral applications. However, many urologists report the material degradation of these polymeric stents when left for long time periods (>15 days) within the patient. Degradation is usually reported in quality terms when referring to the stent. There are reports of stent softening and/or embrittlement which sometimes result in the stent tearing upon removal from the patient. The aim of the present study is to quantify by means of mechanical analysis the polymeric material degradation at different stent types after certain periods of in-vivo use. M A T E R I A L & METHODS: The method of dynamic mechanical analysis (DMA) was considered as the most appropriate so as to achieve the stent material characterization after removal from the patients. This method is widely accepted and in use by material scientists to assess the viscoelastic properties of polymers and plastics. The method can simulate the periodical compression loading imposed by the ureters (contraction) on the stents in a variety of low frequencies (1-15 Hz) and at the body temperature. RESULTS: Dynamic mechanical analysis results from the tests performed in various types of stents left for various periods of time (0-365 days) in patients have clearly shown that material degradation becomes very obvious after certain periods of time. The effect of degradation appears in two forms. Softening of the stent polymer possibly due to interaction with urine, and stiffening of the stent due to the formation of various insoluble salts (encrustations).
102
VITAMIN D R E C E P T O R GENE BSMI AND TAQ1 P O L Y M O R P H I S M S IN T U R K I S H PATIENTS W I T H URINARY T R A C T STONES
R E N A L T U B U L A R A L T E R A R A T I O N BY CRYSTALLURIA INITIATES C A L C I U M OXALATE STONE F O R M A T I O N - AN E X P E R I M E N T A L STUDY BY MEANS OF M D C K - C E L L S
Grren M.R?, Atac F.B. 2, Tekin M.I. 1, Dirim A. 1, Egilmez T. 3, Verdi U. 2, Ozkardes H. IBaskent University, Urology, Ankara, Turkey, 2Baskent University, Medical Biology and Genetics, Ankara, Turkey, 3Baskent University, Urology, Adana, Turkey I N T R O D U C T I O N & OBJECTIVES" Polymorphisms of vitamin D receptor (VDR) gene has recently been reported to be associated with calcium metabolism disorders. We aimed to investigate the correlation between urinary tract stones and VDR gene polymorphisms, namely BsmI and TaqL M A T E R I A L & M E T H O D S : Between May 2003 and June 2004, 72 patients (26 females, 46 males) with a mean age of 49 years (range; 18-78) who have urinary tract stones were evaluated for VDR gene polymorphisms. Patients with urinary tract infection; hyperparathyroidism; gout diathesis; renal tubular acidosis; renal failure; chronic diarrhoeal states; and those receiving thiazide diuretics, angiotensin-converting enzyme (ACE)-inhibitors, glucocorticoids or estrogens were excluded. Results were compared to those obtained from 72 healthy individuals with a mean age of 53 years (range; 21-78). VDR gene BsmI and TaqI polymorphisms were determined by polymerase chain reaction (PCR) -restriction fragment length polymorphism (RFLP).
Lahme S. 1, Feil G. 2, Strohmaier W. 3, Bichler Kfl, Stenzl A. 2 1St. Trudpert Hospital, Urology, Pforzheim, Germany, 2University of Tuebingen, Urology, Tuebingen, Germany, 3Klinikum Coburg, Urology, Coburg, Germany I N T R O D U C T I O N & OBJECTIVES: The mechanism behind stone formation is still unclear. Physicochemical properties alone cannot explain why urinary stones form. Detection of cellular enzymes in the urine, papillary calcifications and the short transit time of the urine in the renal tubule are factors that do not permit crystals to grow to calculi and thus speak for an involvement of the renal tubule in the process of stone formation. In addition animal experiments with a rat model suggest that alteration of the distal renal tubular cell triggers stone formation. M A T E R I A L & METHODS: Experiments were done by means of a cell culture model (Madin Darby Canine Kidney cells, MDCK- cells). MDCK- cells were cultured in DMEM with 10 % fetal calf serum (FCS) at 37 degrees Celsius und 5 % CO 2. 100 U/ml penicillin, 100 ~tg/ml streptomycin and 2 m M glutamine were added. Subculturing was performed with 0.025 % trypsin. Cultures were prepared by plating 2.5 x 104 cells/well in 96-well dishes. Calcium oxalate crystals (COC) with a diameter of 2 lxm were added and cytotoxic effect was determined by photometrical measurement of Lactate-Dehydrogenase (LDH) in cell supematant. In the study group parathormone (PH), vitamin D 3 (VD), allopurinol, oxipurinol and selenium were added.
RESULTS: There were no statistically significant differences in the BsmI and Taq I genotype distribution of VDR gene in control and patient groups. Moreover, a subgroup of 28 cases out of 72 patients were evaluated for hypercalciuria and the results points out that VDR gene BsmI and Taq I polymorphisms are not associated in the development of hypercaleiuria in our population.
RESULTS: PH and VD had no altering effect on the tubule in contrast to the experimental findings from the animal model. On the other hand, a reproducible tubular cell impairment was induced with COC, expressed as a 27%-rise in the LDH concentration in the cell supernatant. Allopurinol, oxipminaol and selenium inhibited this effect. Oxalate concentration and pH did not influence renal tubular alteration by COC.
CONCLUSIONS: Our preliminary data may indicate that BsmI and TaqI polymorphisms of the VDR gene have no impact on urinary tract stone disease. This study is ongoing with the inclusion ofApaI polymorphism and subgroups of hypercalciuria, stone types and hypocitraturia.
CONCLUSIONS: The observations show that COC in the urine can directly damage the renal tubule. These findings indicate that an interaction between COC and the renal tubular cell is significant for urinary stone formation. This effect was inhibited by allopurinol and selenium, a fact that may speak for the use of both substances in the scope of stone metaphylaxis.
103
104
THE SIGNIFICANCE OF " M I N O R " C O M P O N E N T S OF C A L C I U M R E N A L STONES
D Y N A M I C M E C H A N I C A L ANALYSIS OF D I F F E R E N T TYPES OF E N C R U S T E D P O L Y M E R I C U R I N A R Y STENTS BY M A T E R I A L DEGRADATION ASSESSMENT
Trinchieri A. 1 Lizzano R.2, Castelnuovo C.2, Zanetti G.2 ~Ospedale di Lecco, Urology Unit, Lecco, Italy, 2IRCCS Ospedale Maggiore di Milano, Urology Unit, Milano, Italy
Liatsikos E. 1 Mouzakis D?, Bouropoulos N ) , Bithelis G. 3, Barbalias G.1
INTRODUCTION & OBJECTIVES: In calcium renal stones, calcium oxalate (CAOX) and calcium phosphate (CAP) in various crystal forms and states of hydratation can be identified. Calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) are the commonest constituents of calcium stones. CAOX stones may be apparently pure or mixed, usually with CAP or sometimes with uric acid (UA) or ammonium urate. The aim of this study was to compare the clinical and urinary patterns of patients forming calcium stones of different composition.
1University of Patras, School of Medicine, Patras, Greece, 2University of Patras, Department of Material Science, Patras, Greece, 3University Hospital of Patras, Urology, Patras, Greece
MATERIAL & METHODS: The stones of 84 consecutive calcium renal stone formers were examined by infrared spectroscopy. In each patient a blood sample was drawn and analysed for serum biochemistry and a 242hour urine sample was collected and analysed for calcium, phosphate, oxalate, citrate and other electrolytes. We classified 49 patients as calcium oxalate monnhydrate (COM) stone formers, 32 as calcium oxalate dihydrate (COD) stone formers and 3 as apatite stone formers according to the main component of their stones. RESULTS: Mean daily urinary calcium (210+/106 vs 334+/-134 mg/day) and urinary saturation with respect to CAOX (4.85+/-3.10 vs. 7.35+/-3.61) were significantly lower in patients with COM than in those with COD stones (p < 0.000). Patients with CAOX stones containing an UA component (equal or less than 10%) presented with higher saturation (1.83+/-1.31 vs. 1.17+/-0.93, p<0.012) with respect to UA in their urine (and lower with respect to CAOX and CAP, respectively p<0.024 and p<0.003) in comparison with patients without UA component in the stone. Patients with CAOX stones with a CAP component (equal or more than 15%) showed higher (2.03+/-2.52 vs. 1.68+/-2.05, p<0.0016) urinary saturation levels with respect to CAP (and lower with respect to UA, p<0.009) compared with patients forming stones without CAP or with a low CAP component. Patients with calcium stones mixed with UA showed significantly lower urinary pH (5.35+/-0.50 vs. 5.70+/-0.45, p<0.002) and calcium (194+/-i24 vs. 288+/-121 mg/day, p<0.000) and patients with CAP > 15% higher urinary pH (5.86+/-0.34 vs. 5.63+/-0.46, p<0.004) and calcium (342+/-141 vs. 275+/-117 mg/day, p<0.000). CONCLUSIONS: In the evaluation of the individual stone patient an accurate analysis of the stone showing its exact composition and the eventual presence of minor components of the stone is mandatory in order to plan the correct prophylactic treatment. Patients with "calcium stones" could deserve a different approach in relation to the form and hydratation of the calcium crystals in their stones and to the presence of "minor" crystalline components that could have acted as epitaxial factors.
European Urology Supplements 4 (2005) No. 3, pp. 28
I N T R O D U C T I O N & OBJECTIVES: The use of polymeric urinary stents is widespread in many endo-urethral and endo-ureteral applications. However, many urologists report the material degradation of these polymeric stents when left for long time periods (>15 days) within the patient. Degradation is usually reported in quality terms when referring to the stent. There are reports of stent softening and/or embrittlement which sometimes result in the stent tearing upon removal from the patient. The aim of the present study is to quantify by means of mechanical analysis the polymeric material degradation at different stent types after certain periods of in-vivo use. M A T E R I A L & METHODS: The method of dynamic mechanical analysis (DMA) was considered as the most appropriate so as to achieve the stent material characterization after removal from the patients. This method is widely accepted and in use by material scientists to assess the viscoelastic properties of polymers and plastics. The method can simulate the periodical compression loading imposed by the ureters (contraction) on the stents in a variety of low frequencies (1-15 Hz) and at the body temperature. RESULTS: Dynamic mechanical analysis results from the tests performed in various types of stents left for various periods of time (0-365 days) in patients have clearly shown that material degradation becomes very obvious after certain periods of time. The effect of degradation appears in two forms. Softening of the stent polymer possibly due to interaction with urine, and stiffening of the stent due to the formation of various insoluble salts (encrustations).