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Biomedical subjects

G S Benson

Publications and source records attributed to G S Benson.

At least 37 records · Page 2Linked to original sources

The use of indwelling ureteral stents in managing ureteral injuries due to external violence.

Eighteen consecutive cases of ureteral injury due to external violence occurring over a 6-year period were reviewed. The diagnosis of ureteral injury was made either preoperatively on an intravenous urogram, or intraoperatively using indigo carmine. No patient had an isolated ureteral injury. Four patients with ureteral contusions were managed expectantly and needed no further therapy. Eleven patients with ureteral lacerations underwent spatulated, interrupted anastomoses of absorbable suture and placement of Silastic double-J ureteral catheters and had prompt resolution of urinary drainage and normal urograms post stent removal. Two initially nonstented patients with lacerations required delayed ureteral stent placement for massive retroperitoneal urine leakage while one patient did well with simple ureteroureterostomy without stenting. The only important complication from the use of ureteral stents was limited to a single patient, who failed to return for followup and developed a staghorn calculus on the stent. The use of Silastic double-J ureteral catheters resulted in little morbidity and allowed: relatively maintenance-free care; an extra measure of safety in multiply injured patients; and early hospital discharge.

Adolescent↗

Anatomical localization and some pharmacological effects of vasoactive intestinal polypeptide in human and monkey corpus cavernosum.

Vasoactive intestinal polypeptide is hypothesized to be a nonadrenergic, noncholinergic neurotransmitter important in the physiology of penile erection. To further explore this concept, anatomical localization of vasoactive intestinal polypeptide, in vitro muscle bath studies and in vivo injection experiments were undertaken in the monkey and man. Using immunohistochemical techniques vasoactive intestinal polypeptide was localized at the light microscopic level to nerves within the monkey and human penis. Ultrastructurally, a modified peroxidase-antiperoxidase technique was used to identify large vasoactive intestinal polypeptide-positive vesicles within peptidergic and cholinergic varicosities. In the in vitro muscle bath, the addition of 10(-7) M vasoactive intestinal polypeptide did not alter the baseline tension of strips of monkey and human corpus cavernosum. During contraction produced by norepinephrine stimulation, however, vasoactive intestinal polypeptide (10(-7) M) caused relaxation of the monkey (41 +/- 18 per cent, no. = 8) and human (23 +/- 8 per cent, no. = 5) corpus cavernosum. Intracorporal injection of vasoactive intestinal polypeptide (0.75 X 10(-9) to 3.75 X 10(-9) moles/kg.) had no effect on the monkey penis. Administration of vasoactive intestinal polypeptide (1.25 X 10(-9) to 2.5 X 10(-9) moles/kg.) into the internal iliac artery of the monkey, while having no effect on the flaccid penis, caused detumescence of the erect penis obtained by cavernous nerve stimulation (2-5 V, 40 Hz, 2 msec.). Although vasoactive intestinal polypeptide can be found within the nerves of the penis, its apparent in vitro and in vivo effects raise further questions concerning the role of this peptide in penile erection.

Adult↗

Some pharmacologic effects of yohimbine on human and rabbit penis.

The pharmacologic effects of yohimbine on human and rabbit penile tissue were studied in 2 experimental systems. Yohimbine (10(-7) to 10(-4) M), in a dose-related manner, partially antagonized norepinephrine-induced contraction of human corpus cavernosum in an in vitro muscle bath. Yohimbine alone, however, did not alter the baseline tension of strips of human corpus cavernosum. The catecholamine content of the corpus cavernosum and corpus cavernosum urethrae of saline (control) and yohimbine-treated rabbits was determined by high pressure liquid chromatography. There was no statistically significant difference in mean norepinephrine content between control (0.38 +/- 0.29 microgram. per gm. wet wt.) and yohimbine-treated (0.25 +/- 0.21 microgram. per gm. wet wt. at 1 mg. per kg. body wt.; 0.50 +/- 0.10 microgram. per gm. wet wt. at 2 mg. per kg. body wt.) rabbit corpus cavernosum and control (0.53 +/- 0.34 microgram. per gm. wet wt.) and yohimbine-treated (0.86 +/- 32 microgram. per gm. wet wt. at 1 mg. per kg. body wt.; 0.53 microgram. per gm. wet wt. at 2 mg. per kg. body wt.) rabbit corpus cavernosum urethrae. It appears that, in the penis, yohimbine exhibits alpha adrenergic blocking properties and does not affect catecholamine levels in this tissue.

Animals↗

Diagnosis and initial management of urological injuries associated with 200 consecutive pelvic fractures.

During 26 months 200 consecutive patients with fracture of the bony pelvis were evaluated and treated for urological injury. There was no correlation between the extent of pelvic injury and degree of hematuria but hematuria was present in all patients with a urological injury. All urological injuries occurred with anterior arch fractures. The over-all incidence of injury was 13.5 per cent (bladder 9 per cent, urethra 3.5 per cent and combined 1 per cent). Limited extraperitoneal bladder ruptures were treated successfully by Foley catheter drainage.

Adolescent↗

Intermittent clean catheterization: an alternative to diversion in continent transplant recipients with lower urinary tract dysfunction.

A total of 3 renal transplant recipients who were candidates for urinary diversion underwent successful transplantation using a planned program of intermittent clean catheterization. The urinary tract dysfunction was caused by a lower motor neuron neurogenic bladder, prune belly syndrome and myelodysplasia. The patients remain dry between catheterizations and maintain serum creatinine levels of 1.1, 0.8 and 0.5 mg. per cent, respectively, with a followup of 6 to 25 months. There has been only 1 urinary tract infection during 42 patient-months at risk while on self-catheterization. Pre-transplant urologic evaluation and patient education are mandatory. The ideal candidate for intermittent clean catheterization is a patient with a low pressure bladder that fails to empty and who is continent between catheterizations. Intermittent clean catheterization is a safe and effective alternative to diversion in continent transplant recipients with lower urinary tract dysfunction.

Adult↗

The vasculature of the human penis: a reexamination of the morphological basis for the polster theory of erection.

The morphology of human penile blood vessels has been studied to characterize columns of smooth muscle found in the intima. Although previous workers (Kiss, 1921; Conti, 1952) termed these intimal pads or polsters and concluded that they were actively responsible for the production of erection, more recent work has questioned these conclusions (Benson et al., 1980; Newman and Tchertkoff, 1980). Serial sections were taken throughout the length of the penis from 11 cadavers and stained with various histopathological stains. Numerous polster-like structures were found, but all could be identified as either branch points in vessels, intimal cushions located at branch points, or arteriosclerotic lesions at various stages of development. None of these structures seem capable of functioning in the manner attributed to them by Conti (1952) and others. Furthermore, comparison of the structures found in the present study to illustrations of polsters in Conti's paper suggest that these are identical. The present study refutes the polster theory of erection and leaves open to further question the mechanisms involved in the control of blood flow into and within the penis.

Adult↗

Acute focal bacterial nephritis: focal pyelonephritis that may simulate renal abscess.

We report 4 cases of acute focal bacterial nephritis, a solid inflammatory lesion of the kidney. In each patient the findings on excretory urography, when combined with the clinical features, suggested the possibility of a renal abscess. Ultrasonography and computerized tomography aid in distinguishing this solid inflammatory process from that of frank abscess. The possible etiology of acute focal bacterial nephritis, its evolution to abscess formation and its distinguishing features are discussed.

Abscess↗

Penile polsters: functional structures or atherosclerotic changes?

The distribution of blood flow within the penis during erection and detumescence is thought to be controlled by polsters, columns of smooth muscle cells within the intima of penile arteries and veins. We have examined penile tissue from 4 men and 2 children, and have been unable to find incontrovertible evidence of polsters as classically described. Occasional structures superficially resembling polsters were encountered not only in penile tissue but also in vessels in the spermatic cord in patients undergoing vasectomy. In each instance these structures were recognizable as either branching points of vessels, intimal smooth muscle cell cushions or atherosclerotic lesions at various stages of development. Our findings strongly refute the hypothesis that polsters contribute to the normal physiology of erection.

Arteries↗

Effect of dantrolene sodium on canine bladder contractility.

Dantrolene sodium (Dantrium) is currently used in the treatment of detrusorstriated sphincter dyssynergia and is thought to act primarily on striated muscle. The effect of this agent on smooth muscle in general is controversial, and its effect on urinary bladder smooth muscle in particular is not known. In an in vitro muscle bath system, dantrolene was found to have no statistically significant inhibitory effect on acetylcholine-induced canine detrusor muscle contractions.

Acetylcholine↗

Positive bethanechol chloride supersensitivity test in hereditary sensory neuropathy.

An 11-year-old girl with hereditary sensory neuropathy (type II) presented with neurogenic bladder disease. Urodynamic evaluation revealed a sensory neurogenic bladder and a markedly positive bethanechol chloride supersensitivity test. This case report supports Lapides' original observation that a positive bethanechol chloride supersensitivity test may occur in pure sensory neurogenic bladder disease.

Bethanechol Compounds↗

Neuromorphology and neuropharmacology of the human penis: an in vitro study.

The neuromorphology and neuropharmacology of the human penis are only briefly described in literature. The present study was undertaken to define the adrenergic and cholinergic neuromorphology of the human corpus cavernosum (CC) and corpus spongiosum and to evaluate the in vitro response of the CC to pharmacologic stimulation. Human penile tissue was obtained from six transsexual patients undergoing penectomy. For morphologic study, the tissue was processed for (a) hematoxylin and eosin staining; (b) smooth muscle staining; (c) acetylcholinesterase localization; (d) glyoxylic acid histofluorescence; (e) electron microscopy; and (f) electron microscopy after glutaraldehyde dichromate fixation. In addition, strips of CC were placed in in vitro muscle chambers and tension changes recorded isometrically after stimulation with norepinephrine (NE) and acetylcholine. The CC contains abundant smooth muscle, numerous glyoxylic acidfluorescent (catecholaminergic) fibers and varicosities, and a scant distribution of acetylcholinesterase-positive fibers. Fewer of all these elements were present in the corpus spongiosum. No "polsters" were observed in the CC. Although glutaraldehyde-fixed controls exhibited no typical adrenergic vesicles (small, dense core, measuring 400-600 A in diameter), some small, strongly electron-dense vesicles were found in glutaraldehyde dichromate-fixed tissue and were thought to contain NE. A variety of other vesicles were also encountered. The addition of NE to the in vitro muscle chambers caused a dose-related contraction, which was blocked by pretreatment with phentolamine in all CC strips tested. Acetylcholine in high concentration produced minimal contraction in 2 of 24 strips. Our morphologic and pharmacologic data suggest that the sympathetic nervous system may affect erection by acting not only on the penile vasculature but also by direct action on the smooth muscle of the CC itself.

Acetylcholine↗

Vasectomy--1980.

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Adult↗