Extraperitoneal laparoscopy-assisted percutaneous nephrolithotomy in a left pelvic kidney.

Treatment of urolithiasis within a pelvic kidney presents a technical challenge. We report an extraperitoneal laparoscopy-assisted percutaneous approach to access the lower-pole calix of a pelvic kidney for percutaneous nephrolithotomy.

Lambda exonuclease-based subtractive hybridization approach to isolate differentially expressed genes from leaf cultures of Paulownia kawakamii.

Genes that are preferentially expressed in a particular developmental pathway can be isolated by subtractive hybridization (SH). We developed a PCR-based approach coupled with lambda exonuclease digestion that allows for generating single-stranded tester and driver nucleic acids suitable for SH starting from cDNA libraries. An efficient subtraction strategy was developed to overcome some of the problems in the previously described SH protocols, such as the need for large amounts of experimental tissue, RNase contamination during solution hybridization, and postsubtraction recovery of nucleic acids. We used this method to obtain cDNA corresponding to genes expressed during adventitious shoot regeneration from excised leaf cultures of the fast-growing tree Paulownia kawakamii. Over 36 cDNA clones were isolated and 1 of the differentially expressed clones codes for a leucine zipper transcription factor. This clone showed about sixfold higher level of expression in the shoot-forming tissues (tester) compared to that in the callus-forming tissues (driver) of Paulownia, suggesting that differentially expressed genes can be efficiently isolated using this simple lambda exonuclease-based subtractive hybridization method.

Metabolic and urinary risk factors associated with Randall's papillary plaques.

BACKGROUND AND PURPOSE: Increasing evidence suggests that Randall's plaques contribute to the pathogenesis of urinary stone formation. The purpose of our study was to evaluate the urinary risk factors of stone patients who underwent endoscopic mapping of their calices for Randall's plaques. PATIENTS AND MATERIALS: Patients (N = 143) having endoscopic procedures to remove upper tract calculi or for other purposes underwent mapping of their calices for Randall's plaques. Plaque incidence and pattern were correlated with the stone composition and urinary risk factors found on subsequent metabolic evaluation. RESULTS: Papillary plaques were found more commonly in patients having calcium oxalate stones than in patients with other stone types and patients without a history of stones. Papillary plaque incidence and pattern did not correlate with any specific urinary risk factor; however, patients with plaques tended to exhibit a higher incidence of all risk factors. Plaque severity tended to be greater in patients exhibiting hypercalciuria. CONCLUSIONS: Randall's plaques are found most frequently in patients with calcium oxalate stones and are most important in the pathogenesis of calcium oxalate nephrolithiasis. Stone patients with papillary plaques are more likely to exhibit abnormalities in their urinary milieu than are patients without papillary plaques.

Immunohistochemical analysis of BCL-2 protein expression in renal cell carcinoma.

PURPOSE: To investigate the incidence, extent, and distribution of bcl-2 protein expression in human renal cell carcinomas. MATERIALS AND METHODS: Using immunohistochemical tissue staining techniques, bcl-2 protein expression was analyzed in archival nephrectomy specimens removed for renal cell carcinoma or trauma and in 3 renal cell carcinoma cell lines. RESULTS: Normal kidneys demonstrated bcl-2 immunopositivity primarily within the cytoplasm of distal tubule cells. Only rare and minor staining of the proximal tubular cells, thought to be the origin of renal cell carcinoma, was noted in histologically normal controls and areas adjacent to tumor. In contrast, bcl-2 protein expression was demonstrated in 70% of renal cell carcinomas and in all 3 experimental cell lines. CONCLUSIONS: Bcl-2 is a proto-oncogene known to regulate apoptosis (programmed cell death). Bcl-2 protein is overexpressed in the majority of renal cell carcinomas examined. Bcl-2 overexpression may have a role in tumorigenesis and may explain the relative resistance of renal cell carcinoma to chemotherapeutic agents and to radiation therapy.

Nephroscopy sheath characteristics and intrarenal pelvic pressure: human kidney model.

We developed an in vitro human kidney model to study the intrarenal pelvic pressures generated during percutaneous nephroscopy. Higher intrapelvic pressures were associated with nephroscopy sheaths of smaller caliber and greater length. In addition, the position of the sheath within the kidney markedly influenced intrapelvic pressure. The results of this study have influenced our practice and are especially important during cases involving percutaneous removal of infected urinary calculi and transitional-cell carcinoma.

Endoscopic mapping of renal papillae for Randall's plaques in patients with urinary stone disease.

PURPOSE: Papillary "Randall's plaques" are theorized to act as nidi for urinary stone formation. The aim of this study was to document the presence, pattern and distribution of Randall's plaques in patients undergoing endoscopic procedures for urinary stone disease. MATERIALS AND METHODS: Patients undergoing either ureteroscopy or percutaneous nephroscopy for removal of urinary stones underwent endoscopic mapping of accessible calices. These patients were compared to a smaller group of patients undergoing endoscopic procedures for conditions unrelated to urinary stone disease. In patients found to have papillary plaques the presence, location and pattern of plaques were recorded. Plaque formation was correlated with patient age and sex, and primary composition of extricated stone. RESULTS: Endoscopic evidence of papillary Randall's plaques was found in 74% of 57 patients having ureteroscopic (21) or percutaneous (36) stone removal. Of 7 patients having endoscopic procedures for conditions unrelated to urinary stone disease 3 (43%) had evidence of papillary plaques. Plaques were found uniformly throughout all calices and most commonly diffusely scattered over the papillary surface. There was no correlation between patient age or sex and the presence of plaques. The incidence of plaques varied with the primary composition of extracted stones, and was 100% for calcium phosphate and uric acid, 88% for calcium oxalate, 33% for cystine and 20% for struvite. The incidence of papillary plaques was significantly more common in patients with calcium oxalate (88 versus 43%, p = 0.023) and calcium phosphate stones (100 versus 43%, p = 0.009) than patients without a history of urinary stone disease. CONCLUSIONS: The endoscopic incidence of papillary Randall's plaques in patients with urolithiasis varies with the primary composition of formed urinary stones. Randall's plaques are found in the majority of patients with calcium urinary stone disease. Our findings suggest that the presence of papillary plaques is associated with calcium nephrolithiasis and may contribute to the pathogenesis of calcium urinary stones.

Acalculous cystinuria.

We compared quantitative urinary cystine values in stone-forming family members and unaffected relatives based on an index stone-forming patient. A family pedigree of 39 members was identified. Quantitative urinalyses and serum biochemical profiles were collected with the subjects on similar diets over 72 hours. Detailed medical histories were obtained. Three family members are stone-forming cystinuric patients with a mean urinary cystine excretion of 496 mg/g of creatinine per day. Six persons without a history of stones (mean age 50) had a mean urinary cystine excretion of 364 mg/g of creatinine per day. Thirty-four family members had elevated urinary cystine concentrations (mean 151 mg/g of creatinine per day), and only two family members had normal urinary cystine excretion. Fifteen subjects with elevated urinary cystine values (> 150 mg/g of creatinine per day) had no history of urinary stones despite a mean age of 44 years. Urinary electrolytes and volumes were similar in the stone-forming and non-stone-forming groups. Thirty-nine per cent of the persons from this family pedigree had elevated quantitative urinary cystine concentrations and no history of urinary stones despite a mean age of 44 years. Acalculous cystinuria is an elevated urinary cystine concentration without evidence of urinary stone disease. Despite abnormal urinary cystine excretion, acalculous cystinuria does not necessarily culminate in clinical urinary stone disease.

Uric acid-related nephrolithiasis.

Abnormalities in uric acid metabolism are associated with uric acid and calcium oxalate urolithiasis. Clinical stone formation depends on multiple identifiable risk factors that affect uric acid and calcium oxalate solubility. The understanding of urinary pH is critical to direct appropriate treatment of uric acid-related nephrolithiasis. Understanding uric acid metabolism and the pathophysiology of uric acid and calcium oxalate stone formation leads to a rational treatment approach to uric acid and hyperuricosuric calcium oxalate stone disease.

High resolution radiography of cadaveric kidneys: unraveling the mystery of Randall's plaque formation.

PURPOSE: We used high resolution radiography to identify and characterize Randall's plaques in cadaveric kidneys. MATERIALS AND METHODS: A total of 50 consecutive sets of cadaveric kidneys was fixed, bivalved and imaged with micro-focal spot magnification radiography. Papillary calcifications were identified, localized and processed for light microscopy. Special immunohistochemical stains were implemented to aid localization of ectopic calcifications. Patient medical records and autopsy results were retrospectively evaluated and correlated with radiographic papillary calcifications. RESULTS: Of the 92 renal units with complete data 52 (57%) had radiographic evidence of renal medullary calcifications consistent with Randall's plaques. Unlike the original description of this condition, calcifications extended deep into the papilla. A history of hypertension was the only clinical parameter correlating with papillary calcifications. Calcium deposition was localized to the basement membrane of collecting tubules and vasa recta, and papillary interstitium. CONCLUSIONS: Randall's plaques are not merely subepithelial deposits. Rather, they appear to extend deep within the papilla, and are intimately associated with collecting tubules and vasa recta. An association between papillary calcifications and urinary stone formation has yet to be proved but is under investigation.

Dietary manipulation with lemonade to treat hypocitraturic calcium nephrolithiasis.

PURPOSE: Pharmacological treatment of hypocitraturic calcium nephrolithiasis requires as many as 12 tablets, or numerous crystal packages or liquid supplements taken throughout the day. In addition to added cost, this cumbersome regimen decreases patient compliance, which may increase stone recurrence rates. We evaluated the urinary biochemical effects of dietary citrate supplementation in hypocitraturic calcium stone formers in an attempt to decrease or eliminate the need for pharmacological therapy. MATERIALS AND METHODS: A total of 12 patients who were either noncompliant with or intolerant of pharmacological citrate therapy supplemented their routine diet with citrate in the form of lemonade, consisting of 4 ounces of reconstituted lemon juice (5.9 gm. citric acid) mixed with tap water to a total volume of 2 l. and consumed at uniform intervals throughout the day. Urine specimens (24-hour) were obtained for biochemical analysis after 6 days of lemonade therapy and compared to pre-lemonade baseline values. RESULTS: Of the 12 patients 11 had increased urinary citrate levels during lemonade therapy (average 204 mg. per day). Average levels increased from 142 mg. daily (range less than 10 to 293) at baseline to 346 mg. daily (range 89 to 814) after treatment (p < 0.001). Daily total urinary volumes were similar (2.7 versus 2.9 l.). Seven of 12 patients became normocitraturic while consuming lemonade. Urinary calcium excretion decreased an average of 39 mg. daily, while oxalate excretion was unchanged. The lemonade mixture was well tolerated. Two patients complained of mild indigestion that did not require cessation of therapy. CONCLUSIONS: Citrate supplementation with lemonade increased urinary citrate levels more than 2-fold without changing total urinary volume. Lemon juice, which contains nearly 5 times the concentration of citric acid compared to orange juice, is an inexpensive and well tolerated dietary source of citrate. Lemonade therapy may improve patient compliance, and may be useful as adjunctive treatment for patients with hypocitraturic calcium nephrolithiasis.

Outcome assessment of double-J stents during extracorporeal shockwave lithotripsy of small solitary renal calculi.

The utility of indwelling double-J ureteral stents during extracorporeal shockwave lithotripsy (SWL) of renal calculi is ill defined. We evaluated 179 patients treated with SWL for small (< 20 mm in diameter) solitary renal calculi with (N = 27) or without (N = 152) indwelling ureteral stents. There was no significant difference in the stone-free rates at 1 month (both 52%) and 3 months (61% nonstented group v 67% stented group; P = 0.45) or in the retreatment rates (13.3% nonstented group v 14.8% stented group; P = 0.60). The incidence and severity of pain/renal colic were similar for the two treatment groups. There was minimal morbidity associated with SWL in either group. Placement of double-J stents for the purpose of improving stone-free rates, alleviating pain, or preventing ureteral obstruction in conjunction with SWL of solitary renal calculi < 20 mm in diameter is unnecessary.

The influence of diet on urinary stone disease.

PURPOSE: Conflicting data on the role of diet in the pathogenesis of nephrolithiasis prompted us to review the relevant literature regarding the impact of diet on urinary stone disease. MATERIALS AND METHODS: MEDLINE searches were obtained from 1966 to date using a variety of key words, including urolithiasis, nephrolithiasis, diet, protein, carbohydrate, fat, calcium, oxalate, phosphate, magnesium, sulfate, citrate, sodium, potassium, fiber, fluids, alcohol and vitamins. References earlier than 1966 were obtained through bibliographies of these MEDLINE searches. The search included in vitro and in vivo animal and human studies. RESULTS: Of the extracted articles 83% addressed the issue of nephrolithiasis and diet, and were included in this report. All articles were independently reviewed by each of us. The reviews were summarized and compiled according to each dietary component. CONCLUSIONS: Appropriate dietary manipulation may be beneficial in the prevention of recurrent urolithiasis in only a select group of patients.

Sodium fluoride dissolution of human calcium oxalate/phosphate stone particles.

The dissolutive effects of sodium fluoride on human calcium stone particles were investigated in an in vitro model. Stone particles composed of 65% calcium oxalate and 35% calcium phosphate dissolved in a dose-dependent fashion with NaF exposure. Stone particles exposed to 60 mM NaF had a 17% reduction in particle mass after 24 hours and a 62% reduction after 7 days in comparison with experimental controls bathed in physiologic normal saline. The systemic toxicity of the dose of oral fluoride necessary to achieve the optimal tested urinary concentrations would likely preclude oral administration, but NaF may have an adjunctive role in upper urinary tract irrigation for residual stone fragments after lithotripsy or in chronic low-dose oral administration for prophylaxis against recurrent calcium nephrolithiasis.

Nephrostomy tract tumor seeding following percutaneous manipulation of a ureteral carcinoma.

We report a case of nephrostomy tract tumor seeding following percutaneous nephrostomy tube placement and endoscopic manipulation of ureteral carcinoma. While never previously reported to our knowledge, tumor seeding is a potential risk of percutaneous endoscopic management of upper tract urothelial carcinomas.

Endourologist at work: laparoscopic placement of drains after nephrectomy.

The exact indications and ideal candidates for laparoscopic nephrectomy are yet to be identified. Occasionally, urologists might drain the renal fossa, depending on the pathogenesis of the renal disease prompting the nephrectomy, as with chronic infection. The authors describe a technique of placing a closed drainage system under full view with insufflation after laparoscopic nephrectomy. No additional stab wounds are necessary.

Laparoscopic use of the ureteral illuminator.

Laparoscopic identification of the ureters is complicated by decreased tactile sensation and magnified video imaging. We report our experience in placing a ureteral illuminator to aid in ureteral identification prior to six laparoscopic urologic procedures. The ureteral illuminator facilitated laparoscopic ureteral identification during five nephoureterectomies and one ureterolithotomy. Illuminator placement required a minimum of anesthetic time and resulted in no complications. Preoperative placement of a ureteral illuminator aids laparoscopic ureteral identification and may reduce the incidence of inadvertent ureteral injury.

Microfibrillar collagen hemostat during laparoscopically directed liver biopsy.

Meticulous hemostasis is a necessity during laparoscopic procedures in maintaining a clear visual field and avoiding the need for an extended laparotomy to secure hemostasis. Methods of hemostasis available to laparoscopic surgeons include direct pressure, suture/clip ligation, conventional monopolar or argon-enhanced coagulation, and application of topical hemostatic agents. The effectiveness of topical hemostatic agents for open surgical procedures has been demonstrated; however, to date, laparoscopic utilization of topical hemostatic agents has been hampered by lack of compatible forms for laparoscopic instillation. Endo-Avitene is a 15 x 50 mm rolled sheet of microfibrillar collagen hemostat, available in an applicator capable of placement through standard laparoscopic trocar. The use of Endo-Avitene during laparoscopically-directed liver biopsies in a porcine model is reported. The effective hemostatic properties of microfibrillar collagen hemostat were reaffirmed and the clinical utility of Endo-Avitene for laparoscopic use is demonstrated.