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Biomedical subjects

Ojas Shah

Publications and source records attributed to Ojas Shah.

8 recordsLinked to original sources
PubMed2006

The use of alpha-blockers for the treatment of nephrolithiasis.

Medical expulsion therapy has been shown to be a useful adjunct to observation in the management of ureteral stones. Alpha-1-adrenergic receptor antagonists have been studied in this role. Alpha-1 receptors are located in the human ureter, especially the distal ureter. Alpha-blockers have been demonstrated to increase expulsion rates of distal ureteral stones, decrease time to expulsion, and decrease need for analgesia during stone passage. Alpha-blockers promote stone passage in patients receiving shock wave lithotripsy, and may be able to relieve ureteral stent-related symptoms. In the appropriate clinical scenario, the use of alpha-blockers is recommended in the conservative management of distal ureteral stones.

Journal Article↗
PubMed2005

Genetic and dietary factors in urinary citrate excretion.

BACKGROUND AND PURPOSE: Hypocitraturia, an important risk factor for calcium oxalate nephrolithiasis, is the result of numerous factors. We studied citrate excretion by patients with and without stones consuming normal and controlled formula diets. SUBJECTS AND METHODS: Subjects with and without a history of calcium oxalate stones (N = 101 per group) provided two or three 24-hour urine specimens during consumption of self-selected diets. Data also were collected on subsets of subjects consuming formula (Ensure) diets. Citrate was determined using the citrate lyase method of Petrarulo and associates, and values for multiple specimens were averaged. The data were adjusted for creatinine excretion and examined on a per-day basis. RESULTS: The mean citrate excretion of the non-stone formers was slightly but not significantly higher than that of the stone formers (442 +/- 217 versus 378 +/- 153 mg/g of creatinine). All statistical analyses revealed highly significant differences between, but not within, individuals, a result compatible with a genetic influence. In the normal population, 5% of subjects had a citrate excretion <200 mg/g of creatinine, whereas this result was seen in 34% of the stone-forming subjects. When the subjects consumed a formula diet, women in both groups had much higher citrate excretion than when on a self-selected diet, but little difference was seen in the men. The patterns of citrate recovery suggest low, intermediate, and high excretors. In the normal population, 15% of subjects excreted <340 mg/g of creatinine, whereas this was true of 43% of the stone-forming subjects. Analysis of six families suggested three excretor phenotypes, with a codominant pattern of inheritance. CONCLUSION: These findings imply a genetic influence on citrate excretion, as has already been demonstrated for calcium excretion. Further studies of genetic influences on calcium oxalate stone formation are warranted.

Adult↗
PubMed2004

Renal imaging: what the urologist wants to know.

Preoperative imaging in renal surgery is of utmost importance in contemporary surgical practice. From a diagnostic standpoint, imaging discovers many renal tumors incidentally before they become symptomatic. These tumors often are amenable to partial renal resection or minimally invasive surgical approaches. In general, surgical interventions for renal abnormalities have evolved to a less invasive endourologic or laparoscopic approach. Selection of the appropriate surgical intervention for renal tumors, collecting system tumors, and hydronephrosis depends heavily on the anatomy of the renal pathology. Thus, renal imaging is crucial in clinical decision-making. This article reviews the contribution of imaging to the surgical management of renal tumors, upper tract urothelial tumors, and ureteropelvic junction obstruction.

Decision Making↗
PubMed2004

Quartz stones: spurious or iatrogenic?

We describe 2 cases of spurious quartz-containing calculi; the first patient-driven and the second iatrogenic. An iatrogenic etiology can occur after the use of holmium:yttrium-aluminum-garnet laser energy because the fiber tip is composed of quartz. To make the diagnosis of a spurious stone, a high degree of suspicion is essential. A quartz stone should prompt the diagnosis of a factitious disorder in the absence of the appropriate surgical history. Psychological counseling and/or referral to a pain management clinic should be considered in such cases.

Citric Acid↗
PubMed2004

Isolated renal vein thrombosis after blunt trauma.

Renal vein thrombosis typically occurs in the setting of nephrotic syndrome, tumor thrombus, primary retroperitoneal processes with vein compression, oral contraceptive use, steroid therapy, transplanted kidney, or trauma. Trauma-induced renal vein thrombosis usually presents in combination with renal arterial or parenchymal injury. We report a case of isolated renal vein thrombosis secondary to blunt abdominal and flank trauma. The diagnosis was made with computed tomography, which revealed a filling defect in the affected renal vein and persistent nephrogram on delayed images. In general, conservative management is the preferred treatment approach with anticoagulation.

Abdominal Injuries↗
PubMed2003

The New York University nerve sparing algorithm decreases the rate of positive surgical margins following radical retropubic prostatectomy.

PURPOSE: We developed an algorithm that prospectively defines when to excise the neurovascular bundles during radical retropubic prostatectomy with the goal of maximizing the performance of nerve sparing procedures while minimizing positive surgical margins. MATERIALS AND METHODS: From January 1 to December 31, 2000 a single surgeon performed 272 radical retropubic prostatectomies and 263 were performed from January 1 to December 31, 2001. A single pathologist analyzed all specimens with positive margins. There were no prospectively defined criteria to guide decisions regarding excision of the neurovascular bundles in the 2000 study cohort. Gleason score, percent tumor volume and perineural invasion were independently analyzed in the biopsy specimens according to the site of origin (right versus left side) for the 2001 group only. The ipsilateral neurovascular bundle was excised for Gleason 6 or less tumors when there were 50% or greater tumor volume in the biopsy specimen and perineural invasion, for Gleason 7 tumors when there was 30% or greater tumor volume, or perineural invasion and for Gleason 8 to 10 tumors when there was 10% or greater tumor volume, or perineural invasion. RESULTS: There were no statistically significant differences between the 2000 and 2001 groups in regard to preoperative prostate specific antigen, clinical and pathological stage, biopsy Gleason score and percent tumor volume in the surgical specimen. There was a statistically significant decrease in the incidence of positive margins between the 2000 and 2001 groups (14% versus 8%, p = 0.027). The lower positive margin rate was not achieved because of a tendency to excise more neurovascular bundles since a significantly greater percent of neurovascular bundles was preserved in the 2001 group. The sensitivity, specificity, positive and negative predictive values, and accuracy of our algorithm were 18%, 93%, 28%, 89% and 84%, respectively. In sides of the prostate with extraprostatic extension ipsilateral wide excision of the neurovascular bundle was associated with positive margins in 33% of cases compared with 22% when the neurovascular bundle was preserved (p = 0.42). CONCLUSIONS: The New York University nerve sparing algorithm prospectively defines when to excise the neurovascular bundle based on Gleason score, perineural invasion and tumor volume in the biopsy specimen. Use of this algorithm decreases positive surgical margin rates, while significantly increasing the preservation of neurovascular bundles.

Algorithms↗