Tissue distribution of ethanol after intraprostatic injection using a porous needle.

Purpose: To develop a safe and precise method for intraprostatic injection, and to establish correlation between the volume of ethanol injectate and the volume of subsequent infiltrated prostate tissue. Materials and methods: We performed intraprostatic injection of 96% ethanol using a needle which has a segment of its wall made of capillary membrane with hundreds of pores in an acute and chronic canine experiment, in heart-beating cadaveric organ donors, and in a xenograft model of human prostate cancer. Whole mount tissue sections were used for three-dimensional reconstruction of the necrotic lesions and calculation of their volumes. Results: The ethanol injection resulted in oval shaped lesions of well-delineated coagulative necrosis. In both healthy human and canine prostates, the prostatic pseudocapsule and neurovascular bundle remained intact without evidence of disruption. There was a linear correlation between administered volume of ethanol and the volume of necrotic lesion. Regression analysis showed strong correlation in the acute canine experiments and in experiments performed on xenografts of human prostate cancer. A formula was calculated for each experiment to estimate the relationship between the injected volume and the volume of infiltrated prostate tissue area. Conclusions: Intraprostatic injection using a porous needle allows for effective and predictable tissue distribution of the injectate in the prostate. Through varying the volume of the agent injected and use of needles with a different length of the porous segment, the volume of infiltrated tissue could be adjusted allowing for targeted focal treatment.

A Composite Renal Tumor with Dual Differentiation, Chromophobe and Collecting Duct Carcinoma.

Chromophobe carcinoma constitutes a small subset of all renal carcinomas. Within this category, rare tumors with divergent differentiation have been recognized. Herein, we report a rare case of composite chromophobe and collecting duct carcinoma and describe its pathologic and clinical features.

Profile of metabolic and infectious stone-formers in a contemporary PCNL cohort.

INTRODUCTION: To identify factors associated with stone composition in patients undergoing percutaneous nephrolithotomy (PCNL). MATERIAL AND METHODS: A retrospective analysis of patients who underwent PCNL at two academic institutions between 2002 and 2014. Stone composition, stone characteristics based on non-contrast computer tomography (NCCT), patient demographics, and the S.T.O.N.E nephrolithometry scores were compared. Stones were characterized as either infection or metabolic. Metabolic stones were classified as calcium phosphate-containing and all others. RESULTS: A total of 192 renal units underwent PCNL. Retrieved stones were found to be 75% (144) metabolic and 25% (48) infection by stone analysis. Of the metabolic stones, 51% (73) were phosphate-containing calculi. Overall, infection stones were found to have a significantly higher S.T.O.N.E nephrolithometry score than metabolic stones (9.2 versus 8.1, p < 0.001). Average Hounsfield units (HU) were significantly lower in infection stones (765 versus 899, p < 0.05). Sixty-three percent of patients with infection stones were female as compared to 46% of patients with metabolic stones. Patients with phosphate-containing stones in the metabolic group were significantly more likely to be female (56% versus 35%, p < 0.01), younger (mean 49 versus 60 years of age, p < 0.02), and have lower BMI's (30 versus 32, p < 0.02) compared with other metabolic stones. CONCLUSIONS: Patient demographics including age, sex and BMI differ between patients with phosphate and non-phosphate containing metabolic stones. Higher S.T.O.N.E nephrolithometry scores were found in infection stones. These findings may serve as useful tools in the identification of stone compositions that are being seen more frequently in large and complicated stones undergoing PCNL.

Novel Bioceramic Urethral Bulking Agents Elicit Improved Host Tissue Responses in a Rat Model.

Objectives. To test the physical properties and host response to the bioceramic particles, silica-calcium phosphate (SCPC10) and Cristobalite, in a rat animal model and compare their biocompatibility to the current clinically utilized urethral bulking materials. Material and Methods. The novel bulking materials, SCPC10 and Cristobalite, were suspended in hyaluronic acid sodium salt and injected into the mid urethra of a rat. Additional animals were injected with bulking materials currently in clinical use. Physiological response was assessed using voiding trials, and host tissue response was evaluated using hard tissue histology and immunohistochemical analysis. Distant organs were evaluated for the presence of particles or their components. Results. Histological analysis of the urethral tissue five months after injection showed that both SCPC10 and Cristobalite induced a more robust fibroblastic and histiocytic reaction, promoting integration and encapsulation of the particle aggregates, leading to a larger bulking effect. Concentrations of Ca, Na, Si, and P ions in the experimental groups were comparable to control animals. Conclusions. This side-by-side examination of urethral bulking agents using a rat animal model and hard tissue histology techniques compared two newly developed bioactive ceramic particles to three of the currently used bulking agents. The local host tissue response and bulking effects of bioceramic particles were superior while also possessing a comparable safety profile.

The prone ureteroscopic technique for managing large stone burdens.

Percutaneous nephrolithotomy (PCNL) is the standard treatment for patients with large stone burdens, but can be associated with significant complications. Flexible ureteroscopy is an alternative approach that is less invasive, but often requires multiple procedures. Typically, many factors play a role in the decision to perform PCNL or ureteroscopy. The challenge is that it is difficult to predict which stone burdens will be able to be cleared ureteroscopically. We describe our approach using initial prone ureteroscopy with the transition to standard prone PCNL if required.

Rat animal model for preclinical testing of microparticle urethral bulking agents.

OBJECTIVES: To develop an economic, practical and readily available animal model for preclinical testing of urethral bulking therapies, as well as to establish feasible experimental methods that allow for complete analysis of hard microparticle bulking agents. METHODS: Alumina ceramic beads suspended in hyaluronic acid were injected into the proximal urethra of 15 female rats under an operating microscope. We assessed overall lower urinary tract function, bulking material intraurethral integrity and local host tissue response over time. Microphotographs were taken during injection and again 6 months postoperatively, before urethral harvest. Urinary flow rate and voiding frequency were assessed before and after injection. At 6 months, the urethra was removed and embedded in resin. Hard tissue sections were cut using a sawing microtome, and processed for histological analysis using scanning electron microscopy, light microscopy and immunohistochemistry. RESULTS: Microphotographs of the urethra showed complete volume retention of the bulking agent at 6 months. There was no significant difference between average urinary frequency and mean urinary flow rate at 1 and 3 months postinjection as compared with baseline. Scanning electron microscopy proved suitable for evaluation of microparticle size and integrity, as well as local tissue remodeling. Light microscopy and immunohistochemistry allowed for evaluation of an inflammatory host tissue reaction to the bulking agent. CONCLUSIONS: The microsurgical injection technique, in vivo physiology and novel hard tissue processing for histology, described in the present study, will allow for future comprehensive preclinical testing of urethral bulking therapy agents containing microparticles made of a hard material.

Complex renal artery aneurysm managed with hand-assisted laparoscopic nephrectomy, ex vivo repair, and autotransplantation.

A 58-year-old woman had an incidentally found complex right renal artery aneurysm (RAA) during a clinical work-up for diverticulitis. The aneurysm measured 2.5 cm in diameter and was located at the right renal artery bifurcation. She was hospitalized and underwent hand-assisted laparoscopic nephrectomy with ex vivo repair of the RAA and autotransplantation into the right iliac fossa. The same incision was used to remove the kidney from the retroperitoneum as was used to transplant into the right lower quadrant. She tolerated the procedure well. Her postoperative course was uncomplicated. Hand-assisted laparoscopic nephrectomy with ex vivo repair of a complicated RAA and autotransplantation is feasible and safe.

Comparison of intraprostatic ethanol diffusion using a microporous hollow fiber catheter versus a standard needle.

PURPOSE: Transurethral intraprostatic ethanol chemoablation of the prostate has shown promising preliminary clinical results for benign prostatic hyperplasia with some variability in clinical outcome. This is likely due to the uneven prostate diffusion caused by varying resistance of the tissue type in which the tip of the needle is embedded. We examined whether the distribution of the injectable in the canine prostate could be improved using a microporous hollow fiber catheter (Twin Star Medical, Minneapolis, Minnesota). MATERIALS AND METHODS: The prostate was exposed in 9 mongrel dogs. A single injection of 98% ethanol was delivered in each lobe using a microporous hollow fiber catheter and a standard needle. Prostates were harvested and fixed in 10% formalin. After injection 2.5 mm step sections were obtained and scanned. The ethanol induced tissue lesions were traced on hematoxylin and eosin sections. Three-dimensional reconstructions were created and the volume of each prostate lesion was calculated using stereology. RESULTS: Ethanol induced tissue changes were seen bilaterally in 8 of 9 ethanol injected prostates. In all cases the lesion created by microporous hollow fiber catheter injection was larger than that in the contralateral lobe injected with the control needle. When data were pooled, the hollow fiber catheter injection produced significantly greater tissue changes than the control needle injection (p = 0.03). CONCLUSIONS: Improved distribution and absent backflow were seen when using the microporous hollow fiber catheter, supporting its potential as a new method to treat prostate disease.

Gastroesophageal reflux in bronchiolitis obliterans syndrome: a new perspective.

BACKGROUND: Long-term survival after lung transplantation (LTx) is limited largely by bronchiolitis obliterans syndrome (BOS). Gastroesophageal reflux disease (GERD) is proposed as a risk factor for BOS development. This study investigates the relationship between BOS and GERD measured by esophageal impedance. METHODS: After the initiation of routine screening for GERD, 59 LTx recipients underwent ambulatory esophageal impedance monitoring. Exposure to acid reflux and non-acid liquid reflux was recorded. Clinical outcomes were reviewed to analyze any effect of reflux on the time to development of BOS. RESULTS: Thirty-seven (65%) had abnormal acid reflux and 16 (27%) had abnormal non-acid reflux. There was no relationship between acid reflux and BOS. The hazard ratio (HR) for development of BOS in the presence of abnormal non-acid reflux was 2.8 (p = 0.043). The HR for development of BOS increased to 3.6 (p = 0.022) when the number of acute rejection episodes was also taken into account. CONCLUSIONS: GERD is prevalent in LTx recipients and may represent a modifiable risk factor for BOS. This study found non-acid reflux, measured by esophageal impedance to be associated with the development of BOS. Prospective studies are now required to investigate a causal association between GERD and the development of BOS and to establish the role of surgery for GERD in preventing progression to BOS. The methods used to identify GERD in future studies may be important.