New double-lumen polyethylene cannula for push-pull perfusion of brain tissue in vivo.

A new concept in the design of a push-pull cannula device for localized perfusion of brain tissue in the conscious and/or unrestrained animal is described. A catheter, consisting of a single strand of polyethylene tubing, contains an internal dividing septum which runs longitudinally throughout its length. The orifice of each lumen is of equal diameter and provides an integrated system for simultaneous delivery and withdrawal of a perfusate from the perfusion locus. The principal features of the new cannula system are: its simplicity of fabrication due to its all-plastic construction; multiple tip configurations adapted for a specific anatomical requirement including V-shaped, slanted, horizontal and side-by-side opening; direct visualization of the perfusate monitor bubble through the wall of the transparent catheter; since there are no joints, lack of leakage of perfusate and occlusion of pull channel; ease of sterilization by liquid or gas methods; and infrequency of damage because of catheter flexibility. Using radiolabeled dopamine and norepinephrine, prototype experiments carried out with 3 flow rates and 3 tip configurations revealed differences in substrate exchange which depend upon a given experimental parameter. The practical advantages are discussed of the new perfusion system in comparison with dialysis needles as well as with more commonly used concentric, metallic push-pull cannulae. Finally, technical applications are presented of the methods for the rat and other animals in which either the pharmacological delivery of a drug over a specified interval, or recovery of a neurotransmitter released into the cerebral parenchyma is a principal experimental objective.

Survival after right radical nephrectomy and resection of suprarenal vena cava.

The problems relating to injury and the resection of the suprarenal vena cava during a right nephrectomy may well confront every urologic surgeon. Although such a procedure is compatible with survival, postoperative temporary renal dysfunction may occur and a plan to deal with this problem should be formulated.

Transurethral vesicovaginal extraction of stone: nonoperative approach for intramural ureteral calculi in women.

Herein we describe a new technique for the removal of an impacted intramural ureteral calculus in a female patient. The stone was extracted by digital manipulation with the index finger of one hand in the bladder and the index and middle fingers of the other hand in the vagina. The relative ease of performing the procedure and the absence of any immediate and long-term postoperative morbidity and complications warrant further use of this technique.

Recurrent intraurethral proliferation of ectopic prostatic tissue associated with hematuria.

The first reported case of recurrent intraurethral proliferation of ectopic prostatic tissue associated with hematuria is presented.

Urinary obstruction secondary to prostatic involvement from postoperative extension of carcinoma of rectosigmoid.

Two cases of urinary obstruction secondary to neoplastic involvement of the prostate from abdominal-perineal resection for carcinoma of the rectosigmoid are discussed. A review of the literature and the management of this infrequent entity is described.

Efficacy of candicidin in benign prostatic hypertrophy.

Forty-three patients with benign prostatic hypertrophy with marked urinary distress, which I believed warranted surgical treatment, were selected from private practice. These patients were treated with long-term conservative therapy to determine the efficacy of candicidin for this condition. Patients receiving candicidin orally 300 mg. per day showed improved subjective symptoms in 89.3 per cent of cases compared to 18.2 per cent for patients treated by placebos. Residual urine was decreased in 85.7 per cent and flow rate was improved in more than 89 per cent of the cases. More than one third of the patients treated with candicidin showed improvement in prostate size compared to none for patients treated with placebos. Occasional gastric upset was the only adverse effect attributed to candicidin, which appears to be a safe and efficacious agent.