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Biomedical subjects

D A Schulsinger

Publications and source records attributed to D A Schulsinger.

9 recordsLinked to original sources
PubMed2000

Acute histologic changes in human renal tumors after cryoablation.

BACKGROUND AND PURPOSE: Cryoablation is a treatment option for some patients with small, exophytic lesions of the kidney. Several investigators have evaluated the effects of cryoablation in normal renal tissue of animals. The purpose of this study was to investigate the tissue changes following cryoablation in human renal tumors. PATIENTS AND METHODS: We prospectively evaluated patients with solid renal lesions (1.5-1.8 cm) confirmed by CT, MRI, or both. Metastatic work-up for all patients was negative. All lesions were biopsied prior to freezing. Two patients with bilateral renal tumors underwent argon-gas-based CRYOcare System (Endocare, Irvine, CA) treatment via an open approach. A 3-mm cryoprobe was placed directly into each tumor. A single 15-minute freeze preceded an active thaw (helium gas) for each lesion. Iceball dimensions were monitored by intraoperative ultrasonography. After successful cryoablation, partial nephrectomy was performed to remove the lesion, and the renal tissue underwent histologic evaluation. RESULTS: The cryoprobes achieved a temperature of -135 degrees C. No bleeding was noted, and there were no intraoperative or postoperative complications with a mean follow-up of 3 months. Histologically, freezing of renal tissue resulted in coagulative necrosis and hemorrhage beyond the boundaries of the lesions. There was a zone of demarcation between the viable and nonviable tissue. CONCLUSIONS: In our series, cryoablation was effective in destroying tumor tissue in vivo in human kidneys. Freezing was sufficient to achieve a negative surgical margin. Cryoablation of renal tumor is an alternative to the currently available nephron-sparing surgical techniques. The long-term effect of tumor tissue destruction by cryosurgery requires further investigation.

Aged↗
PubMed1999

Acute and chronic interstitial cryotherapy of the adrenal as a treatment modality.

Adrenalectomy is indicated for patients with large adrenal lesions or functional tumors. Cryoablation is currently used as a surgical alternative for the treatment of prostate, lung, brain, pharynx, and liver tumors. The purpose of this study was to determine if cryosurgery could be delivered to small areas in the adrenal gland in a controllable and reproducible manner such that tissue could heal in a nonpathologic way. A total of 14 female mongrel dogs underwent acute (n = 8) or chronic (4 weeks, n = 6) cryoablation using the Cryounit. In the acute study using an open transabdominal approach a 2-mm cryoprobe was placed interstitially into the adrenal tissue, whereas 0.032-inch thermocouples were cannulated into the ipsilateral adrenal artery and vein. Adrenal parenchymal temperature changes were measured using 0.032-inch thermocouples placed at 0.4- and 0.8-cm intervals from the cryoprobe. In the chronic study, cryoablation was achieved by transperitoneal laparoscopic access using a standard laparoscopic technique. Interstitial cryoprobe temperatures decreased from 33.1 +/- 1.9 degrees C to -148 +/- 1.2 degrees C following 15 min of freezing in the acute study. Cryoablation of adrenal tissue achieved temperatures of -41.8 +/- 5.7 degrees C and -21.8 +/- 1 degrees C at distances of 0.4 and 0.8 cm from the cryoprobe, respectively. There was no significant change in adrenazl artery or vein temperatures during cryoablation. Histologically there is a clear demarcation between viable and nonviable tissue characterized by areas of multifocal hemorrhage and pyknosis. After 4 weeks of healing a well-defined line of necrotic and viable tissue is visible. Cryoablation of the adrenal can be delivered in an effective, controllable, and reproducible manner. This controllable energy form may provide a new treatment modality for tissue destruction where adrenal gland preservation is necessary and can be performed by the laparoscopic approach. Understanding the effect of adrenal cryoablation may allow us to treat selected patients with small tumors where organ preservation is necessary.

Adrenal Gland Diseases↗
PubMed1999

Acute and chronic interstitial cryotherapy of the adrenal gland as a treatment modality.

BACKGROUND AND OBJECTIVES: Adrenalectomy is indicated for patients with large adrenal lesions or functional tumors. Cryoablation is currently used as a surgical alternative for the treatment of prostate, lung, brain, pharynx, and liver tumors. The purpose of this study was to determine if cryosurgery could be delivered to small areas in the adrenal gland in a controllable and reproducible manner, so that tissue could heal in a nonpathological way. MATERIALS AND METHODS: Fourteen female mongrel dogs underwent acute (N = 8) or chronic (4 weeks) (N = 6) cryoablation using the Cryounit. In the acute study, using an open transabdominal approach, a 2-mm cryoprobe was placed interstitially into the adrenal tissue, while 0.032-inch thermocouples were cannulated into the ipsilateral adrenal artery and vein. Adrenal parenchymal temperature changes were measured using thermocouples placed at 0.4- and 0.8-cm intervals from the cryoprobe. In the chronic study, cryoablation was achieved by transperitoneal laparoscopic access using standard laparoscopic technique. RESULTS: Interstitial cryoprobe temperatures decreased from 33.1 +/- 1.9 degrees C to -148 +/- 1.2 degrees C following 15 minutes of freezing in the acute study. Cryoablation of adrenal tissue achieved temperatures of -41.8 +/- 5.7 degrees C and -21.8 +/- 1 degrees C at distances of 0.4 and 0.8 cm from the cryoprobe, respectively. There were no significant changes in adrenal artery or vein temperatures during cryoablation. Histologically, there was a clear demarcation between viable and nonviable tissue, the latter being characterized by areas of multifocal hemorrhage and pyknosis. After 4 weeks of healing, there was a well-defined line between necrotic and viable tissue. CONCLUSION: Cryoablation of the adrenal gland can be obtained in an effective, controllable, and reproducible manner. This controllable energy form may provide new modality for tissue destruction where adrenal gland preservation is necessary and can be delivered by the laparoscopic approach. Understanding the effect of adrenal cryoablation may allow us to treat selected patients with small tumors in whom organ preservation is necessary.

Adrenal Glands↗
PubMed1998

The "Wedge" resection device for electrosurgical transurethral prostatectomy.

The "Wedge" (Microvasive, Natick MA) is a new electroresection device for transurethral prostatectomy (TURP) using the standard resectoscope. The design, which is broader than the standard loop and thickens from front to back, results in better hemostasis when used at 275 to 300 W because of its ability to cut and coagulate tissue simultaneously. In the canine model, histologic examination demonstrated a 2-mm zone of coagulation around the chips and in the resection bed; this response was not observed in the specimens resected by the standard tungsten loop. No adjacent tissue damage was found with either the Wedge or the loop, and the temperatures recorded at the capsule rose only 4 degrees C regardless of the device used. In the 65 patients treated, the average hematocrit drop on postoperative Day 1 was 3.0%, and serum sodium was unchanged. One year postoperatively, the peak flow rate had increased by 101%, and the AUA Symptom Score was 6.1. The only surgical complication was urethral strictures (3%) necessitating incision. Most striking was the increased case of resection attributable to improved intraoperative vision. The data suggest that Wedge TURP is as safe and efficacious as standard loop TURP. The surgical field is markedly improved and clear because of intraoperative hemostasis. A TURP can be performed with a view toward minimizing patient morbidity and increasing surgical ease.

Animals↗
PubMed1998

Renal calculus disease.

We have seen an explosion in technical innovations for the management of urolithiasis. Today, the endourologist possesses an assortment of minimally invasive tools to treat renal stones. Most patients receive fast, safe and effective treatment in the outpatient setting. Despite the many technical advances, however, anatomical malformations and complex stones still provide significant challenges in diagnosis, access to a targeted stone, fragmentation, and clearance of the resulting fragments. This review examines a variety of urinary stone presentations and treatment strategies for cost-effective management.

Journal Article↗
PubMed1997

Activation of endothelium-derived relaxing factor system in acute unilateral ureteral obstruction.

PURPOSE: To investigate the effects of 1-arginine, a substrate for nitric oxide (NO) synthase, on renal hemodynamics in acute ureteral obstruction (UUO). MATERIALS AND METHODS: Renal blood flow (RBF) and ureteral pressure (UP) were measured in anesthetized dogs with or without UUO. RESULTS: In 9 dogs (Group 1), RBF was 212 +/- 13 ml./min. before UUO, and significantly increased to 302 +/- 18 and 268 +/- 9 ml./min. at 90 and 140 min. post-UUO, respectively, associated with a marked increase in UP from 3 +/_ 1 mm. Hg to 73 +/- 5 and 83 +/-2 mm. Hg at 90 and 140 min. post-UUO, respectively. In 6 dogs (Group 2) prostaglandin synthesis was inhibited with meclofenamate (5 mg./kg., i.v.). After UUO, RBF did not change significantly and the increase in UP was markedly attenuated when compared with Group 1, as UP rose only to 27 +/-3 and 34 +/- 4 mm. Hg at 90 and 140 min. post-UUO, respectively. In 6 dogs pre-treated with meclofenamate, L-arginine was infused into the renal artery at 5 mg./kg./min. at 90 min. after UUO (Group 3). Prostaglandin synthesis inhibition prevented renal vasodilation after UUO and significantly attenuated the increase in UP. Upon infusion of L-arginine, RBF and UP rose sharply from 202 +/- 16 ml./min. and 24 +/- 6 mm. Hg to 264 +/- 22 ml./min. and 70 +/- 4 mm. Hg, respectively, at 140 min. post-UUO (p <0.001), values approaching those in Group 1. In sham-operated dogs, L-arginine infusion did not alter RBF in dogs with or without pretreatment with meclofenamate. CONCLUSION: In UUO the L-arginine-NO pathway is activated, contributing to renal vasodilation and a marked increase in UP.

Acute Disease↗
PubMed1994

Unilateral multicystic dysplasia in 1 component of a horseshoe kidney: case reports and review of the literature.

We report on 3 pediatric patients with multicystic dysplasia involving 1 component of a horseshoe kidney. Including our cases, 18 cases of unilateral multicystic dysplasia in a horseshoe kidney have been reported. The clinical, radiological and pathological features of these cases are briefly reviewed. The association of multicystic dysplastic kidney and horseshoe kidney presents a unique diagnostic challenge. Because of the rarity of unilateral multicystic dysplasia in a horseshoe kidney and the size of the dysplastic component, which crossed the midline in our patients, we chose to excise that component. Cross-sectional imaging techniques, that is computerized tomography and magnetic resonance imaging, were helpful in diagnosis and in planning operative treatment.

Child, Preschool↗
PubMed1989

Effect of dietary protein quality on development of aflatoxin B1-induced hepatic preneoplastic lesions.

The effect of the quality of dietary protein on the post-initiation development of aflatoxin B1-initiated putatively preneoplastic foci in Fischer 344 rat liver was compared with the effect of the quantity of dietary protein. Feeding wheat gluten, a low-quality protein, during the postinitiation period (between the end of aflatoxin B1 dosing and the death of the rats) inhibited the development of gamma-glutamyltransferase-positive foci when compared with that in animals fed high-quality protein (casein) diets during the same period. Lysine supplementation of wheat gluten during the postinitiation period enhanced the gamma-glutamyltransferase-positive response to a level comparable with that of the high-quality protein. These results suggest that one can inhibit the development of foci either by decreasing the quantity of protein intake and holding the quality of the protein constant or by decreasing the quality and holding the quantity constant.

Aflatoxin B1↗