Biomedical subjects

Paramjit S Chandhoke

Publications and source records attributed to Paramjit S Chandhoke.

10 recordsLinked to original sources

PubMed2006

Does a slower treatment rate impact the efficacy of extracorporeal shock wave lithotripsy for solitary kidney or ureteral stones?

PURPOSE: We compared the efficacy of an SR (70 to 80 shocks per minute) and an FR (120 shocks per minute) for ESWL for solitary stones less than 2 cm located in the kidney or proximal ureter. MATERIALS AND METHODS: A total of 349 patients with a solitary, radiopaque kidney or ureteral stone underwent ESWL on a DoLi(R) 50 lithotriptor. Patients were grouped based on stone size, stone location and whether SR or FR treatment was performed. Of the 349 patients 135 had a renal stone between 1and 2 cm, 137 had a renal stone less than 1 cm and 77 had a proximal ureteral stone with a surface area of between 30 and 90 mm. SFRs were determined at approximately 1 month by plain x-ray of the kidneys, ureters and bladder. RESULTS: In comparison to the FR groups SR groups required fewer shocks and had significantly lower power indexes. Of patients with renal stones between 1 and 2 cm 24 of 52 (46%) in the FR group were stone-free compared to 56 of 83 (67%) in the SR group (p <0.05). For stones with a surface area of 30 to 90 mm located in the kidney or proximal ureter there was a trend toward an improved SFR in the SR group but differences between the SR and FR groups were not statistically significant. CONCLUSIONS: For solitary renal stones between 1 and 2 cm an SR results in a better treatment outcome than an FR for ESWL. However, when stone size is less than 1 cm, SFR differences in the SR and FR treatment groups become less significant.

Female↗

PubMed2005

Gender Differences among Hispanics and Caucasians in symptomatic presentation of kidney and ureteral stones.

PURPOSE: We determined gender differences in the symptomatic presentation of kidney and ureteral stones among the Hispanic population and compared it with presentation in the Caucasian population. PATIENTS AND METHODS: A retrospective chart review was performed on 443 patients seen in our Emergency Department or Urgent Care Center for symptomatic kidney or ureteral stones over a 5-year period. Demographic information was obtained, including sex, race, age, location of stone, stone size, and type of urologic intervention. Of the 443 patients, 263 (59%) were Hispanic, and 180 (41%) were Caucasian. RESULTS: The male-to-female ratio of the symptomatic patients with kidney stones was 1.48 for both Hispanic and Caucasian patients. The male-to-female ratio for ureteral stones was 1.06 and 2.48 for the Hispanic and Caucasian patients, respectively (P < 0.05). The rate of urologic intervention was similar among Caucasian males and females and Hispanic females (approximately 33%) but significantly lower among Hispanic males (18%). CONCLUSIONS: The relative symptomatic presentation of ureteral stones of men and women among the Hispanic population is nearly 1:1, whereas the ratio in Caucasian men and women approaches the previously reported 2.5:1. No significant racial or sex differences were noted in the symptomatic presentation of kidney stones. In comparison with Hispanic men, Hispanic women undergo significantly more urologic interventions for symptomatic urolithiasis.

Adult↗

PubMed2005

Oxalate toxicity in cultured mouse inner medullary collecting duct cells.

PURPOSE: Oxalate, a metabolic end product and a major constituent of the majority of renal stones, has been shown to be toxic to renal epithelial cells of cortical origin. However, to our knowledge it is unknown whether inner medullary collecting duct (IMCD) cells, which are physiologically exposed to higher concentrations of oxalate, also behave in a similar manner. MATERIALS AND METHODS: A line of IMCD cells was exposed to oxalate (0.2 to 10 mM) for various time points. Trypan blue, and hematoxylin and eosin stains were used to assess cell morphology and membrane integrity. The production of reactive oxidative species was determined using the nitro blue tetrazolium reaction and crystal violet staining was used to measure cell density. RESULTS: Exposure of IMCD cells to oxalate produced time and concentration dependent changes in the light microscopic appearance of the cells. Long-term exposure to oxalate resulted in alterations in cell viability with net cell loss following exposure to concentrations of 2 mM and greater. Free radical production was time and concentration dependent. Crystal formation occurred in less than 1 hour and cells in proximity to crystals lost membrane integrity. Compared to IMCD cells LLC-PK1 and HK2 cells showed significant toxicity starting at lower oxalate concentrations (0.4 mM and above). CONCLUSIONS: To our knowledge the results provide the first direct demonstration of toxic effects of oxalate in IMCD cells, a line of renal epithelial cells of the inner medullary collecting duct, and suggest that cells lining the collecting duct are relatively resistant to oxalate toxicity.

Animals↗

PubMed2004

Effects of oxalate on IMCD cells: a line of mouse inner medullary collecting duct cells.

Oxalate, a metabolic end product and a major constituent of the majority of renal stones, has been shown to be toxic to renal epithelial cells of cortical origin. However, it is unknown whether inner medullary collecting duct (IMCD) cells that are physiologically exposed to higher concentrations of oxalate also behave in a similar manner. In the present study, we examined the effects of oxalate on IMCD cells. IMCD cells from the mouse were maintained in DMEM/F12 media supplemented with fetal bovine serum and antibiotics. Exposure of IMCD cells to oxalate produced time- and concentration-dependent changes in the light microscopic appearance of the cells. Long-term exposure to oxalate resulted in alterations in cell viability, with net cell loss after exposure to concentrations of 2 mM or greater. The production of free radicals was directly related to the exposure time and the concentration of oxalate. Crystal formation occurred in less than 1 h and cells in proximity to crystals would lose membrane integrity. Compared with IMCD cells, LLC-PK1 cells as well as HK-2 cells showed significant toxicity starting at lower oxalate concentrations (0.4 mM or greater). These results provide the first direct demonstration of toxic effects of oxalate in IMCD cells, a line of renal epithelial cells of the inner medullary collecting duct, and suggest that the cells lining the collecting duct are relatively resistant to oxalate toxicity.

Animals↗

PubMed2003

The urinary response to an oral oxalate load in recurrent calcium stone formers.

PURPOSE: Dietary oxalate may contribute up to 50% to 80% of the oxalate excreted in urine. We studied the urinary response to an oral oxalate load in male and female idiopathic recurrent calcium oxalate stone formers with and without mild hyperoxaluria to evaluate the potential pathophysiological significance of dietary oxalate. MATERIALS AND METHODS: A total of 60 recurrent calcium stone formers underwent an oral oxalate load test. Urine samples were obtained after an overnight fast. Each patient then received an oral oxalate load (5 mM. sodium oxalate dissolved in 250 ml. distilled water) and 3, 2-hour urine samples were obtained 2, 4 and 6 hours after the oxalate load. We compared the response to the oxalate load in patients with and without mild hyperoxaluria, and in male and female patients without hyperoxaluria. RESULTS: The peak urinary response occurred 4 hours after the oral oxalate load in all patients. Those with mild hyperoxaluria had a mean fasting urinary oxalate-to-creatinine ratio +/- SE of 0.027 +/- 0.003 and a mean peak urinary oxalate-to-creatinine ratio of 0.071 +/- 0.006. In comparison, patients with normal oxalate excretion had a fasting and peak urinary oxalate-to-creatinine ratio of 0.018 +/- 0.001 and 0.056 +/- 0.004, respectively (p <0.05). The mean 6-hour increment for urinary oxalate excretion after the oxalate load for patients with hyperoxaluria versus those with normal urinary oxalate excretion was 17.2 +/- 1.9 versus 12.1 +/- 0.98 mg. (p <0.05). In the subset of patients with normal urinary oxalate excretion mean 6-hour cumulative urinary oxalate excretion was 16.8 +/- 1.3 and 13.3 +/- 1.4 mg. in males and females, respectively (p not significant). CONCLUSIONS: Recurrent calcium stone formers with mild hyperoxaluria have higher fasting urinary oxalate and an exaggerated urinary response to an oral oxalate load compared with recurrent calcium stone formers with normal urinary oxalate excretion. Men and women stone formers without hyperoxaluria excrete similar fractions of an oral oxalate load. Increased gastrointestinal absorption and renal excretion of dietary oxalate may be a significant pathophysiological mechanism of stone formation in patients with mild hyperoxaluria.

Administration, Oral↗

PubMed2002

Is lower pole caliceal anatomy predictive of extracorporeal shock wave lithotripsy success for primary lower pole kidney stones?

PURPOSE: The management of lower pole kidney stones is controversial. We examined whether lower pole caliceal anatomy could predict the success of extracorporeal shock wave lithotripsy of primary lower pole kidney stones 20 mm. or less. MATERIALS AND METHODS: From December 1997 to June 2001, 246 adults with a single, 20 mm. or less radiopaque lower pole renal stone were treated with the Doli 50 lithotriptor (Dornier Medical Systems, Marietta, Georgia) while under general anesthesia. Of the 246 patients 190 (77%) had excretory urography available for review. Lower pole infundibular length and width, lower pole infundibulopelvic angle and caliceal-pelvic height were measurable on 161 (85%), 129 (68%), 128 (67%) and 163 (86%) excretory urograms, respectively. Extracorporeal shock wave lithotripsy was considered a failure if residual stone fragments remained after 1 month, or an auxiliary procedure or re-treatment was required. RESULTS The overall stone-free rate was 78% (32 of 41) for stones 5 mm. or less, 73% (98 of 135) for stones 6 to 10 mm., 43% (22 of 51) for stones 11 to 15 mm. and 30% (7 of 19) for stones 16 to 20 mm. in maximum linear dimension. The stone-free rates grouped according to stone surface area were 76% (48 of 63 stones) for stone surface area 25 mm.2 or less, 69% (97 of 141) for 26 to 100 mm.2 and 33% (14 of 42) for 101 to 400 mm.2. Caliceal anatomy was not predictive of success even with stones grouped as 10 or less or 11 to 20 mm. Grouping patients with favorable (lower pole infundibulopelvic angle 70 degrees or greater, lower pole infundibular length 30 mm. or less and lower pole infundibular width greater than 5 mm.) versus unfavorable (70 degrees or less, greater than 30 mm. and 5 mm. or less, respectively) anatomy was also not predictive of success. CONCLUSIONS: On the Doli 50 machine stone size rather than caliceal anatomy is predictive of treatment outcome. Initial treatment failures with this machine should be managed by alternative endoscopic procedures if necessary rather than by repeat shock wave lithotripsy.

Female↗

PubMed2002

When is medical prophylaxis cost-effective for recurrent calcium stones?

PURPOSE: Medical management is generally recommended for recurrent calcium stones to prevent future episodes. However, in this era of extracorporeal shock wave lithotripsy and outpatient ureteroscopy it is not known whether medical prophylaxis is more cost-effective than treatment of recurrent stone episodes. The cost of medical prophylaxis was compared with the cost of clinically managing recurrent stone episodes, and the stone recurrence rate without prophylaxis (stone frequency) at which these 2 treatment approaches became cost equivalent was determined. MATERIALS AND METHODS: An international cost survey was conducted in 10 countries to compare costs of medical prophylaxis and managing recurrent acute stone episodes. Costs of an acute stone episode included an emergency room visit, associated radiographic imaging to confirm diagnosis of a symptomatic stone and outpatient treatment of upper urinary tract stones that did not pass spontaneously. Costs of medical management included an initial limited metabolic evaluation, drug therapy, a followup office visit every 6 months that included a 24-hour urinalysis and radiographic imaging of the kidneys, ureters and bladder once a year. RESULTS: Costs of medical prophylaxis and managing an acute stone episode varied significantly from country to country. The stone frequency at which costs of these management options became equivalent ranged from 0.3 to 4 stone episodes a year. CONCLUSIONS: Medical management of a first stone episode is not cost-effective. Cost analysis should be individualized for specific health care plans to determine which practice patterns are most cost-effective for a particular patient with recurrent calcium stone formation.

Acute Disease↗

PubMed2002

Hyperuricosuric calcium nephrolithiasis.

Since the findings of Yü and Gutman [1], the hyperuricosuric calcium stone former is a unique clinical entity. While an impressive number of clinical and epidemiologic studies implicate hyperuricosuria in calcium stone formation, the exact physicochemical mechanism by which uric acid affects calcium oxalate crystallization has not been proven. Allopurinol decreases stone recurrences and is the drug of choice for patients with isolated HCN.

Allopurinol↗

PubMed2002

A randomized outcomes trial of ureteral stents for extracorporeal shock wave lithotripsy of solitary kidney or proximal ureteral stones.

PURPOSE: Routine use of ureteral stents before extracorporeal shock wave lithotripsy of kidney stones between 10 and 20 mm. is controversial. We conducted a prospective randomized clinical trial to evaluate the outcome of ureteral stents for treating solitary kidney stones between 10 and 20 mm. or solitary proximal ureteral stones less than 20 mm. with shock wave lithotripsy. MATERIALS AND METHODS: A total of 97 patients who met the aforementioned criteria were randomized between March 1994 to July 1997 into group 1-no stent, group 2-a 4.7Fr multi-length stent and group 3-a 7Fr multi-length stent. The patients were treated with the Dornier HM3 lithotriptor (Dornier Medical Systems, Inc., Marietta, Georgia) and monitored for stone-free rate, number of days lost from work, number of patients requiring rehospitalization, emergency room visits, irritative voiding symptom score and pain symptom score. RESULTS: Objective outcome was obtained from 91 patients based on a followup of at least 3 months. The overall stone-free rate was 80%, with a re-treatment rate of 7%. The number of days lost from work was approximately 2, with no significant differences among individual groups or subgroups. The hospitalization rate and number of emergency room visits in group 1 (22%) were statistically higher compared to groups 2 (7%) and 3 (7%). The irritative voiding symptom score was statistically higher in the stented groups 2 and 3 compared to the nonstented group 1. CONCLUSIONS: Although ureteral stents are associated with more irritative symptoms, their use resulted in fewer hospital readmissions and emergency room visits compared to when no stent was used to treat solitary kidney stones of 10 to 20 mm. or solitary proximal ureteral stones less than 20 mm. Size 4.7Fr stents may be preferable over 7Fr stents when used in conjunction with shock wave lithotripsy.

Adult↗

PubMedDate not supplied

Is stone radiodensity a useful parameter for predicting outcome of extracorporeal shockwave lithotripsy for stones < or = 2 cm?

PURPOSE: Several factors determine the success of extracorporeal shockwave lithotripsy (SWL) for kidney stones: stone size, stone location within the collecting system, stone type, and the SWL machine used. It has been suggested that stone radiodensity, as determined either by plain radiography or computed tomography attenuation values, may be an independent predictor of SWL success. We examined the outcome of SWL for solitary stones less than or equal to 2 cm located within the renal pelvis, based on their radiodensity. MATERIAL AND METHODS: 211 patients with solitary renal pelvic stones measuring less than or equal to 2 cm were treated on a Dornier Doli 50 lithotriptor under general anesthesia. The radiodensity of the stone was determined to be either less than, equal to, or greater than the radiodensity of the ipsilateral 12th rib. Stone-free rates (SFR) were determined at 3 months by kidney, ureters and bladder (KUB) plain X-rays. Patients requiring re-treatment or auxiliary procedures were considered failures of SWL. RESULTS: Follow-up SFR information was available in all 211 patients. Stone composition was available in 158 (75%) treated patients, but no correlation was found between stone radiodensity and stone composition. For stones < or = 10 mm within the renal pelvis, the SFRs were similar (71 to 74% regardless of stone radiodensity). For stones between 11 and 20 mm, the SFR was 60% if the stone had a radiodensity > 12th rib compared to a SFR of 71% if the stone radiodensity was < or = 12th rib. However, these differences in SFRs were not statistically significant. CONCLUSIONS: On the Doli machine, stone radiodensity alone does not predict lithotripsy treatment outcome for stones < or = 1 cm within the renal pelvis. This parameter is probably only useful as the stone size becomes larger than 1 cm, and should be used in conjunction with other stone parameters to select appropriate therapy.

Absorptiometry, Photon↗