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Dive into the research topics where Gyan Pareek is active.

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Featured researches published by Gyan Pareek.


The Journal of Urology | 2005

Meta-analysis of the complications of laparoscopic renal surgery : Comparison of procedures and techniques

Gyan Pareek; Sean P. Hedican; Jason R. Gee; Reginald C. Bruskewitz; Stephen Y. Nakada

PURPOSE We performed a meta-analysis of the literature to define the current expectations of complications during laparoscopic renal surgery. MATERIALS AND METHODS References were searched in the MEDLINE database from 1995 to 2004 using the terms complications and laparoscopic nephrectomy. Inclusion criteria were any series with greater than 20 cases, patient age older than 16 years and any complications listed for certain procedures, including laparoscopic radical nephrectomy, HA laparoscopic radical nephrectomy, LPN, HALPN, laparoscopic donor nephrectomy, HA laparoscopic donor nephrectomy, laparoscopic simple nephrectomy, laparoscopic nephroureterectomy and retroperitoneal laparoscopic nephrectomy. A data extraction form was created to categorize major or minor complications. A 5 member panel adhered to the strict criteria and extracted data from articles that met inclusion criteria. Data were entered into a spreadsheet and a meta-analysis was performed. RESULTS Initial review identified 73 of 405 references that were acceptable for retrieval and data extraction, of which 56 met inclusion criteria. The overall major and minor complication rates of laparoscopic renal surgery were 9.5% and 1.9%, respectively. There was a significant difference between the major complication rates of LPN and HALPN (21.0% vs 3.3%, p <0.05). CONCLUSIONS Our results show that patients who undergo laparoscopic renal surgery may have an overall major complication rate of 9.5%. The highest major complication rate is associated with technically challenging LPN (21%). There appears to be a significantly higher wound complication rate associated with HA surgery in comparison to that of standard laparoscopy (1.9% vs 0.2%, p <0.05).


The Journal of Urology | 2003

The Effect of Finasteride on the Expression of Vascular Endothelial Growth Factor and Microvessel Density: A Possible Mechanism for Decreased Prostatic Bleeding in Treated Patients

Gyan Pareek; Maria Shevchuk; Noel A. Armenakas; Ljiljana Vasjovic; David A. Hochberg; Jay B. Basillote

PURPOSE Several studies have confirmed the benefit of finasteride in limiting hematuria from benign prostatic hyperplasia. Vascular endothelial growth factor (VEGF), a potent stimulator of angiogenesis, and microvessel density have been independently evaluated in the mechanism of decreased bleeding observed in patients treated with finasteride. We evaluated the expression of VEGF and suburethral prostatic microvessel density in patients with benign prostatic hyperplasia treated with finasteride. MATERIALS AND METHODS The study included 24 patients undergoing prostatic surgery for benign disease, of whom 12 were given finasteride for a minimum of 6 weeks before surgery and the remaining 12 served as controls. Sections from the prostatic urothelium and hyperplastic prostate were individually stained for CD34 specific for nascent blood vessels and VEGF. Analysis of each specimen was performed in a blinded fashion. Microvessel density was calculated by counting the number of positively stained blood vessels on 10 consecutive, nonoverlapping, high power fields within the suburethral and hyperplastic prostate compartments. VEGF expression was examined by immunohistochemistry. Statistical analysis of the results was performed using Students t test. RESULTS Prostatic suburethral VEGF expression and microvessel density were significantly lower in the finasteride group compared to controls (p <0.05). Differences in VEGF expression and microvessel density at the level of the hyperplastic prostate were not found to be significantly different between the 2 groups. CONCLUSIONS Decreased expression of VEGF by finasteride inhibits angiogenesis and significantly decreases microvessel density in prostatic suburethral tissue. This sequential relationship provides histochemical insight into the mechanism by which finasteride reduces prostatic urethral bleeding.


The Journal of Urology | 2001

Periprostatic nerve blockade for transrectal ultrasound guided biopsy of the prostate: a randomized, double-blind, placebo controlled study.

Gyan Pareek; Noel A. Armenakas

PURPOSE We performed a randomized, double-blind, placebo controlled study to assess the safety and efficacy of periprostatic anesthesia administration during prostate biopsy. MATERIALS AND METHODS From May to November 2000 transrectal ultrasound guided prostate biopsy was performed in 132 consecutive men due to an abnormal digital rectal examination and/or elevated prostate specific antigen. During biopsy 66 patients each were randomly assigned to receive an injection of 1% lidocaine or normal saline. Immediately after biopsy the pain score was recorded independently by patients and the physician using a 10-point linear scale. In addition, patients were given a descriptive questionnaire to be completed at home and mailed back within 2 weeks of biopsy. RESULTS Mean patient perceived pain scores plus or minus standard deviation of 2.7 +/- 0.21 in the lidocaine and 4.7 +/- 0.26 in the saline groups were significantly different (p <0.0001), as were mean physician perceived scores of 2.9 +/- 0.27 and 5.1 +/- 0.34, respectively (p = 0.0001). Mean questionnaire scores for pain during biopsy of 2.3 +/- 0.13 in the lidocaine and 3.1 +/- 0.18 in the saline groups were also significantly different (p = 0.0006), as were mean questionnaire scores for pain after biopsy of 1.8 +/- 0.11 and 2.3 +/- 0.13, respectively (p <0.006). There were no adverse effects of injection. CONCLUSIONS Our results show a significant benefit of periprostatic anesthesia over placebo in a randomized double-blind trial. This safe, simple and rapid technique should be applied at transrectal ultrasound guided prostate biopsy to limit undue patient discomfort.


The Journal of Urology | 2002

Decreased Suburethral Prostatic Microvessel Density In Finasteride Treated Prostates: A Possible Mechanism For Reduced Bleeding In Benign Prostatic Hyperplasia

David A. Hochberg; Jay B. Basillote; Noel A. Armenakas; Liliana Vasovic; Maria Shevchuk; Gyan Pareek

PURPOSE We evaluated the influence of finasteride on prostatic microvessel density to elucidate a mechanism of decreased bleeding in finasteride treated patients with hematuria secondary to benign prostatic hyperplasia (BPH). MATERIALS AND METHODS A total of 22 patients with clinical BPH and gross hematuria who underwent prostate reductive surgery between 1998 and 2000 were prospectively evaluated. The prostate from 10 finasteride treated and 12 untreated patients was immunohistochemically stained for CD-34. Microvessel density analysis was performed by quantifying positive stained blood vessels located within the stroma of hyperplastic nodules as well as in the suburethral portion of the prostate. RESULTS Mean microvessel density plus or minus standard deviation in finasteride treated patients was significantly lower in the suburethral portion of the prostate versus untreated controls (14.0 +/- 2.8 versus 20.2 +/- 5.3 vessels per high power field, p <0.05). In the nodular hyperplasia there was no statistically significant difference in the treatment and control groups (mean 17.5 +/- 2.8 and 16.7 +/- 4.6 vessels per high power field, respectively). CONCLUSIONS Finasteride significantly decreases suburethral prostatic microvessel density in patients with BPH, which may explain its efficacy for decreasing BPH associated bleeding.


Urologia Internationalis | 2009

Hounsfield Units on Computed Tomography Predict Calcium Stone Subtype Composition

Sutchin R. Patel; George E. Haleblian; August Zabbo; Gyan Pareek

Introduction: Hounsfield unit (HU) determination of urinary stones on noncontrast computed tomography (NCCT) has been shown to predict stone composition. However, no in vivo studies have attempted to radiographically separate the various calcium stone compositions. We investigate the efficacy of HU measurement on NCCT to determine if it can differentiate the various calcium stone subtypes. Patients and Methods: Of the 684 patients who had undergone ureteroscopy at our institution from 1/2003 to 10/2007, 100 were identified with a documented NCCT, a chemical stone analysis and a stone size >5 mm but <2 cm. Results: Stone compositions were categorized as 100–80% calcium oxalate monohydrate (CaOMH) (n = 24), <80–60% CaOMH (n = 21), <60–50% CaOMH (n = 11) calcium oxalate dihydrate (CaODH) (n = 16), apatite (n = 9), brushite (n = 4), cystine (n = 2) and uric acid (n = 13). Mean HU were 879 ± 230, 769 ± 295, 717 ± 304, and 517 ± 203 for the 100–80% CaOMH, <80–60% CaOMH, <60–50% CaOMH and CaODH groups, respectively. The average HU for the apatite, brushite, cystine and uric acid groups were 844 ± 346, 1,123 ± 254, 550 ± 74 and 338 ± 145, respectively. The CaOMH groups together had a significantly higher HU than the CaODH group (p < 0.05) and a significantly lower HU than the brushite group (p < 0.05). Conclusions: HU measurement of urinary stones on NCCT may be used to separate some calcium stone subtypes, specifically CaOMH and CaODH. This information may be useful in counseling patients on treatment options for patients requiring intervention.


Urology | 2010

Percutaneous Nephrolithotomy Can Be Safely Performed in the High-risk Patient

Sutchin R. Patel; George E. Haleblian; Gyan Pareek

OBJECTIVES To determine whether percutaneous nephrolithotomy (PCNL) can be safely performed in the high-risk patient. METHODS The records of 84 patients undergoing 98 consecutive PCNL procedures from January 2005 to January 2007 at a single institution were examined. Patients were divided into a high-risk preoperative group, which comprised patients having American Society of Anesthesiologist scores of III or IV (n = 25) and a low-risk preoperative group of patients with an American Society of Anesthesiologist score of II or less (n = 59). RESULTS A total of 33 and 65 procedures were performed in the high- and low-risk groups, respectively. The high-risk group had significantly more comorbidities than the low-risk group (5.4 vs 1.5) (P <.001). No significant difference was noted in the mean cumulative stone size for single or multiple stones in either group. A significant difference was observed between the average anesthesia time (45 vs 25 minutes) and average length of hospital stay (4.0 +/- 3.5 vs 2.7 +/- 1.2 days) but no significant difference in estimated blood loss (132 vs 150 mL) or mean operative time (118 vs 100 minutes) between the high- and low-risk groups, respectively. The overall complication rate was similar between the high-risk (12.1%) and low-risk (12.3%) groups (P = .41). The stone-free rate for the high-risk group was 61% compared with 92% for the low-risk group (P = .028). CONCLUSIONS PCNL can be safely performed in the high-risk preoperative patient population.


Urology | 2015

Rectal swab culture-directed antimicrobial prophylaxis for prostate biopsy and risk of postprocedure infection: a cohort study.

Jessica Dai; Andrew Leone; Leonard A. Mermel; Kathleen Hwang; Gyan Pareek; Stephen Schiff; Dragan Golijanin; Joseph Renzulli

OBJECTIVE To examine the effect of rectal swab culture-directed prophylaxis on the incidence of prostate biopsy-associated infections. Secondary objectives were to determine the rate of fluoroquinolone resistance and extended-spectrum beta-lactamase production in local rectal flora. METHODS All men receiving prostate biopsies from February 2013 to February 2014 were included in a retrospective institutional review board-approved study. All received either a preprocedural rectal swab and culture-directed antimicrobial prophylaxis or routine fluoroquinolone antibiotics. Clinical information was collected on infectious complications treated within 30 days of biopsy. Chi-square test, Fisher exact test, and Welch t test were used for statistical analysis. Confounding variables were included in a multivariate logistic regression model. RESULTS Of 487 total patients, 314 received preprocedure rectal cultures and 173 did not. Average ages were 62.7 and 64.1 years, respectively (P = .07). There was no difference in mean prostate-specific antigen value (P = .9), Charlson comorbidity score (P = .8), or ethnicity (P = .1). The rectal swab group was more likely to receive supplemental gentamicin (P < .001) and had fewer infectious complications (1.9% vs 2.9%; P = .5). On multivariate analysis, decreased odds of infection was associated with culture-directed antibiotics (odds ratio, 0.70; 95% confidence interval, 0.20-2.50; P = .6). However, the study was only powered to detect a 97% reduction in infections. The incidence of fluoroquinolone resistance and extended-spectrum beta-lactamase production was 12.1% and 0.64%, respectively. CONCLUSION Our study was underpowered but suggests that there are lower odds of infection with rectal swab-directed antimicrobial prophylaxis. The local incidence of fluoroquinolone resistance is high. A prospective, randomized, controlled trial is warranted to further evaluate this intervention.


Urology | 2010

An unbiased prospective report of perioperative complications of robot-assisted laparoscopic radical prostatectomy.

Michael Lasser; Joseph Renzulli; George Turini; George E. Haleblian; Harry C. Sax; Gyan Pareek

OBJECTIVES To analyze and classified our single-institution experience with the perioperative complications associated with robot-assisted laparoscopic radical prostatectomy (RALRP). METHODS A total of 239 patients with a mean age of 60.6 years were evaluated (January 2007 to June 2008). Data were collected through an institutional review board-approved blinded prospective database by an independent third party committee. The data-points accrued were set forth by a 5-member panel including 3 robotic urological surgeons (J. R., G. H., G. P.), the chief of general surgery (H. S.), and a member of the hospitals outcomes committee. The Modified Clavien system was used to grade complications, with grade I and II representing minor and grade III, IV, and V major complications. RESULTS Of our 239 patients, 198 (82.9%) had an uneventful postoperative course, defined as discharged home from the hospital within 2 days postoperatively with no unscheduled procedures/studies/hospital admissions or emergency room visits. On review of the remaining 41 patients, 55 complications were found. Of these, 24 were grade I, 17 grade II, 7 grade IIIa, 5 grade IIIb, 1 grade IVa, and 1 grade V complications. There was 1 perioperative mortality (0.4%) attributed to a pulmonary embolism on autopsy. Blood loss data revealed 1 (0.4%) intraoperative transfusion and 9 (3.8%) postoperative transfusions. CONCLUSIONS RALRP is associated with major and minor complication rates of 5.0% and 14.6%, respectively. Prospective and blinded data on complications associated with RALRP are lacking in the published data. Our prospective, unbiased data provide an important tool to help counsel patients on complications associated with robot-assisted laparoscopic radical prostatectomy.


Urology | 2012

Relationship Between Serum Vitamin D and 24-Hour Urine Calcium in Patients With Nephrolithiasis

Brian H. Eisner; Simone Thavaseelan; Sonali Sheth; George E. Haleblian; Gyan Pareek

OBJECTIVE To examine the relationship between serum 25-OH vitamin D and 24-hour urine calcium in patients with nephrolithiasis. METHODS A retrospective review was performed. Patients evaluated in 2 metabolic stone clinics were included for analysis. Multivariate linear regression models were adjusted for known risk factors for stone disease (age, gender, body mass index, hypertension, diabetes mellitus, gout, relevant medications, and 24-hour urine composition). RESULTS One-hundred sixty-nine patients were included in the study. Female to male ratio was 69:100, mean age was 50.9 years (SD 13.7), and mean body mass index was 27.4 (SD 6.4). Vitamin D deficiency (25-OH vitamin D <20 ng/mL) was present in 18.9% of patients, vitamin D insufficiency (>20, <30 ng/mL) was present in 34.9% of patients, and vitamin D was within normal limits (≥ 30 ng/mL) in 46.1% of patients. On age-adjusted and multivariate linear regression, serum 25-OH vitamin D was not related to 24-hour urine calcium (age adjusted β = -0.31 m 95% CI -1.9 to 1.3; multivariate adjusted β = 0.08, 95% CI -1.3 to 1.5). CONCLUSION Although 25-OH vitamin D is involved in the bodys calcium homeostasis, our study does not show a relationship between serum vitamin D level and 24-hour urine calcium excretion in stone-formers. This information may have implications regarding the safety of vitamin D repletion in patients with nephrolithiasis.


BJUI | 2005

Haemostatic partial nephrectomy using bipolar radiofrequency ablation

Gyan Pareek; Eric R. Wilkinson; David J. Schutt; James A. Will; Thomas F. Warner; Dieter Haemmerich; David M. Mahvi; Stephen Y. Nakada

To determine whether an electrode array with a bipolar radiofrequency ablation (RFA) energy source can be used to perform a haemostatic partial nephrectomy by simultaneously ablating and coagulating renal tissue.

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