Biomedical subjects

Michael W Phelan

Publications and source records attributed to Michael W Phelan.

6 recordsLinked to original sources

PubMed2006

Venacavoscopy during nephrectomy for renal cell carcinoma with inferior vena caval thrombus.

PURPOSE: Renal cell carcinoma with inferior vena caval thrombus remains a complex challenge for the urologist. Aggressive surgery to remove all tumor can result in long-term survival. Liver transplant techniques, assistance from cardiac surgeons and bypass techniques can yield optimal vascular control but there is still a blind element inside the inferior vena cava when the thrombus is evacuated. We present data on a technique using a flexible cystoscope to evaluate the lumen of the intrahepatic and suprahepatic inferior vena cava after nephrectomy and tumor thrombectomy. MATERIALS AND METHODS: Seven patients underwent radical nephrectomy and tumor thrombectomy for renal cell carcinoma with inferior vena caval thrombus. During surgery and after removal of the tumor thrombus a flexible cystoscope was inserted into the venacavotomy for direct inspection of the inferior vena caval lumen. Any residual tumor was manipulated out of the lumen and removed. Patient records were reviewed for data on the time of this procedure, estimated blood loss, residual tumor, postoperative complications and survival. RESULTS: Venacavoscopy required an average additional 5.6 minutes and residual tumor was found in 3 of 7 patients. Average estimated blood loss was 1,170 cc and it was not affected by venacavoscopy. One patient experienced acalculous cholecystitis, possibly as a result of this procedure. Mean followup was 17.6 months with 5 of 7 patients alive. CONCLUSIONS: Venacavoscopy is a safe, reliable method of intraoperative inspection of the inferior vena cava that uses equipment and techniques familiar to every urologist. This can help prevent incomplete thrombectomy and disastrous pulmonary embolus.

Aged↗

PubMed2004

Gene therapy using replication-defective herpes simplex virus vectors expressing nerve growth factor in a rat model of diabetic cystopathy.

Diabetic cystopathy is one of the common complications of diabetes and current therapy is limited. In the present study, the effects of gene therapy, using replication-defective herpes simplex virus type 1 (HSV-1) vectors to deliver and express the nerve growth factor (NGF) gene (HSV-NGF) on tissue NGF levels and bladder function, were evaluated in streptozotocin (STZ)-induced diabetic rats. Diabetic rats exhibited a significant decrease in NGF levels in the bladder and lumbosacral dorsal root ganglia (DRG) detected by enzyme-linked immunosorbent assay and displayed marked bladder dysfunction 12 weeks after STZ injection. In contrast, rats with bladder wall injection of the NGF expression vector 8 weeks after STZ treatment exhibited a significant increase of NGF levels in the bladder and L6 DRG 4 weeks after HSV-NGF injection. Along with the restoration of tissue NGF expression, in metabolic cage studies and cystometry, HSV-NGF-injected rats also showed significantly reduced bladder capacity and postvoid residual volume than diabetic rats injected with the control vector (HSV-lacZ), indicating that voiding function was improved after HSV vector-mediated NGF gene delivery. Thus, HSV vector-mediated NGF gene therapy may prove useful to restore decreased NGF expression in the bladder and bladder afferent pathways, thereby improving hypoactive bladder function in diabetes.

Animals↗

PubMed2003

Laparoscopic partial nephrectomy and minimally invasive nephron-sparing surgery.

Surgical extirpation remains the most effective therapy for renal cell carcinoma. The surgical management of renal masses has evolved away from radical nephrectomy and now includes nephron-sparing surgery for small tumors. Nephron-sparing surgery has similar cure rates and does not appear to compromise cancer control. As the detection of small renal masses by widespread abdominal imaging continues to increase, so will the demand for minimally invasive nephron-sparing procedures. Despite progress in surgical techniques, laparoscopic partial nephrectomy remains a technically challenging procedure. In this review, we discuss the challenges and recent advances in laparoscopic partial nephrectomy and other minimally invasive approaches to renal masses.

Carcinoma, Renal Cell↗

PubMed2003

Treatment of renal transplant ureterovesical anastomotic strictures using antegrade balloon dilation with or without holmium:YAG laser endoureterotomy.

OBJECTIVES: To report our results after antegrade endoscopic treatment of ureteral stenosis with balloon dilation with or without holmium laser endoureterotomy. Ureteral stenosis is the most common long-term urologic complication of renal transplantation. METHODS: From July 2000 to October 2002, 9 renal transplant patients with ureteral obstruction diagnosed by an increase in serum creatinine and radiologic evidence presented for endoscopic treatment. All patients were treated with nephrostomy tube drainage followed by antegrade flexible nephroureteroscopy and balloon dilation of the stricture. Three patients required holmium laser endoureterotomy during the same procedure because of fluoroscopic and endoscopic evidence of persistent stricture. All patients were treated with ureteral stents and nephrostomy tubes postoperatively. The median follow-up was 24 months (range 6 to 32). RESULTS: The site of stenosis was at the ureterovesical anastomosis in all patients, and the mean stricture length was 0.28 cm. Two patients had previously undergone ureteroneocystostomy for prior ureteral stenosis. Six patients (66%) required only balloon dilation, and 3 patients (33%) also required holmium laser endoureterotomy. The median ureteral stent and nephrostomy tube duration was 40 and 62 days, respectively. The mean serum creatinine level was 2.3 mg/dL at presentation and 1.7 mg/dL at the last follow-up visit. After a median follow-up of 24 months, the ureteral patency and graft function rates were both 100%. No perioperative complications occurred. CONCLUSIONS: Balloon dilation with or without holmium laser endoureterotomy was successful and safe in this group of renal transplant patients with short ureterovesical anastomotic strictures.

Catheterization↗

PubMed2003

Quality of life, pain and return to normal activities following laparoscopic donor nephrectomy versus open mini-incision donor nephrectomy.

PURPOSE: We evaluated pain, convalescence and health related quality of life in patients undergoing laparoscopic and open mini-incision donor nephrectomy. MATERIALS AND METHODS: We compared the records of consecutive patients who underwent laparoscopic and mini-incision open donor nephrectomy from our donor nephrectomy data base in retrospective fashion using 2 questionnaires. The first questionnaire evaluated postoperative pain, return to functioning time and satisfaction. The second questionnaire was the RAND 36-Item Health Survey, version 2, a standardized and validated health survey quality of life assessment tool. Mean patient sex, age and followup were similar for the 2 groups. All data were analyzed using the 2-tailed t test for independent variables with commercially available statistical analysis software. RESULTS: Pain in the laparoscopic group was significantly less than in the mini-incision group at all followup time points (p <0.05). Statistically significant differences demonstrated that laparoscopy led to more rapid recovery time in certain categories, including walking, discontinuation of prescribed oral pain relievers, return to driving, and resumption of normal work and home daily activities. More subjective questions in the survey showed high levels of acceptance for the 2 procedures. Using the RAND 36-Item Health Survey, version 2 health related quality of life was significantly higher in the laparoscopy group in 3 domains that measure bodily pain, physical functioning and emotional role functioning. However, each group scored at or above age matched American averages in all domains. CONCLUSIONS: The laparoscopy group had significantly less postoperative pain and required less time to return to normal functional activities than the mini-incision group. In addition, the laparoscopic group showed significantly higher quality of life scores than the mini-incision group in 3 domains.

Activities of Daily Living↗

PubMed2002

Diabetic cystopathy correlates with a long-term decrease in nerve growth factor levels in the bladder and lumbosacral dorsal root Ganglia.

PURPOSE It has been proposed that a deficiency in the axonal transport of nerve growth factor (NGF) may have an important role in inducing diabetic neuropathy, which contributes to diabetic cystopathy. Therefore, in streptozotocin (Sigma Chemical Co., St. Louis, Missouri) induced diabetic rats we investigated the relationship of bladder function with NGF levels in the bladder and lumbosacral dorsal root ganglia, which contain afferent neurons innervating the bladder. MATERIALS AND METHODS At 6 and 12 weeks after the induction of diabetes with streptozotocin (65 mg./kg. intraperitoneally) the effects of diabetes on Adelta afferent fiber dependent, conscious voiding were evaluated by metabolic cage measurements and awake cystometry. The effects of diabetes on C-fiber mediated bladder nociceptive responses were also investigated by cystometry with intravesical instillation of 0.25% acetic acid in the rats under urethane anesthesia. NGF levels in the bladder and L6 to S1 dorsal root ganglia were measured by enzyme-linked immunosorbent assay 3, 6, 9 and 12 weeks after streptozotocin injection. RESULTS In diabetic rats NGF levels in the bladder and L6 to S1 dorsal root ganglia were significantly decreased 12 weeks after streptozotocin injection (p <0.01). In cystometry and metabolic cage studies bladder capacity and post-void residual volume were significantly increased 12 weeks after streptozotocin injection (p <0.01). Bladder nociceptive responses revealed by a reduction in inter-contraction intervals after acetic acid infusion were significantly decreased in a time dependent manner 12 weeks after streptozotocin injection.CONCLUSIONS Rats with streptozotocin induced diabetes mellitus showed a significant time dependent decrease in NGF levels in the bladder and L6 to S1 dorsal root ganglia that was associated with voiding dysfunction attributable to defects in Adelta and C-fiber bladder afferents. Therefore, reduced production of NGF in the bladder and/or impaired transport of NGF to L6 to S1 dorsal root ganglia, which contain bladder afferent neurons, may be an important mechanism inducing diabetic cystopathy.

Animals↗