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Biomedical subjects

T F Lue

Publications and source records attributed to T F Lue.

At least 19 recordsLinked to original sources
PubMed1992

Congenital defect in sinusoidal smooth muscles: a cause of organic impotence.

We report 2 cases of primary impotence due to a congenital defect in the compliance of the sinusoidal spaces secondary to fibrosis and atrophy of the smooth muscles. Both patients were young adults at presentation. Diagnosis of this rare entity was achieved by penile Doppler ultrasound and cavernosometry/cavernosography of the cavernous bodies. Both patients underwent placement of a penile prosthesis, during which biopsy samples of the cavernous tissue were obtained, and diagnosis was confirmed by light and electron microscopy.

Adult↗
PubMed1992

The combined intracavernous injection and stimulation test: diagnostic accuracy.

A retrospective review was done of the results of the combined intracavernous injection and stimulation test, an office based functional test for impotence. In this procedure the quality of erection is assessed 15 minutes after injection of a vasoactive drug. In our series 90 patients did not achieve full rigidity and were instructed to perform genital self-stimulation for 5 minutes before reevaluation. Of the 90 patients 67 (74%) improved with stimulation and 23 (26%) showed no improvement. At 5 minutes after stimulation a decrease in the quality of the erection was found in 25 patients--a finding suggestive of venogenic impotence. When cavernosometry and cavernosography were performed 21 patients (84%) had moderate to severe venous leakage and 4 (16%) showed none. Self-stimulation after diagnostic injection of intracavernous agents can improve patient response, and may better predict the potential success of a therapeutic self-injection program and the diagnosis of suspected venogenic impotence.

Adult↗
PubMed1992

Implantable penile venous compression device: initial experience in the acute canine model.

We have designed a venous compression device implantable at the base of the penis outside the tunica albuginea. Because it does not require exposure of individual veins for ligation, the risk to the cavernous nerve is practically nil. It occludes the venous return only temporarily, and thus collaterals are less likely to occur. In this preliminary acute study in dogs (N = 13), the penile venous compression device was shown to be effective and safe in controlling penile venous drainage and maintaining rigid erection.

Animals↗
PubMed1992

Effect of intracavernous simultaneous injection of acetylcholine and vasoactive intestinal polypeptide on canine penile erection.

We investigated the effects of intracavernous injection of a combination of acetylcholine (ACh) and vasoactive intestinal polypeptide (VIP) on the erectile response in eleven adult male dogs. The minimum dose of ACh which increased the intracavernous pressure in eight dogs varied from 0.2 to 40 micrograms, and the minimum dose of VIP varied from 0.2 to 5 micrograms. When the minimum doses of ACh and VIP were injected simultaneously, a strong increase of intracavernous pressure (the mean increase was 102 cm. H2O from the baseline level) and a sustained erection (mean 5 min.) were observed in all eight dogs. The effect of simultaneous injection of both drugs was not additive but synergistic. Pretreatment with VIP-antibody and atropine intracavernously suppressed the erectile response induced by cavernous nerve stimulation. VIP may increase the affinity of muscarinic receptors for ACh in canine corpus cavernosum because pretreatment with atropine alone before the simultaneous injection of ACh and VIP completely abolished the effect of the combination. We conclude that ACh and VIP may play a cooperative role in canine penile erection.

Acetylcholine↗
PubMed1992

Response of bladder, urethral and intracavernous pressure to ventral lumbosacral root stimulation in Sprague-Dawley and Wistar rats.

Six Sprague-Dawley and six Wistar rats were used for electrostimulation of the L5 to S2 ventral roots. Landmarks for identification of the roots were developed; bladder, urethral and intracavernous pressures were recorded; and tail and leg movements were checked. Urethral sphincter contraction was elicited by stimulation of the L5-L6 ventral roots, while bladder contraction and penile erection were mediated by the L6-S1 ventral roots. The best sphincteric response and intracavernous pressure rise were obtained by stimulation of the L6 ventral root, and the highest bladder pressures by stimulation of the S1 ventral root. Stimulation of the S1-S2 ventral roots provoked ipsilateral tail movement; of L6, tail movement, hindleg muscle twitch, and slight toe spread; and of L5, hindleg stretch and plantar flexion. No significant differences were found between the two strains of rats, although a higher bladder pressure was recorded during stimulation of the L6 ventral root in Sprague-Dawley rats, which might be explained by a small caudal shift of the sacral parasympathetic nucleus in the Wistar strain.

Animals↗
PubMed1992

Effects of adenosine on canine penile erection.

We investigated the hemodynamic effects of intracavernous injection of adenosine on canine penile erection. In all ten dogs studied, adenosine induced a dose-dependent increase of intracavernous pressure (ICP). Adenosine (0.67 to 15 micrograms/kg., B.W.) increased arterial blood flow by 83 to 325 percent above baseline levels and also increased venous resistance, which resulted in a full erection (ICP = 80 to 140 cm. H2O) for one to 7 minutes. The repeatability of the adenosine effect was confirmed in eight dogs. We found that adenosine, by virtue of its smooth muscle relaxation properties, can induce a dose-dependent increase of ICP and cause a full erection in dogs.

Adenosine↗
PubMed1992

Correction of penile deformity assisted by intracavernous injection of papaverine.

Sexual dysfunction resulting from penile deformity is amenable to surgical correction. We describe a simplified technique in which surgical plication with nonabsorbable sutures is assisted by intraoperative erection induced by intracavernous papaverine. This procedure can be performed in an ambulatory surgery center with the patient under local anesthesia with minimal postoperative morbidity. To date we have treated 6 patients and followup ranges from 12 to 24 months. All patients have straight erections and retain normal erectile function.

Aged↗
PubMed1992

High-flow priapism and glans hypervascularization following deep dorsal vein arterialization for vasculogenic impotence.

Microsurgical penile revascularization is becoming an increasingly applied technique in patients with arteriogenic or mixed arteriogenic and venogenic impotence. Deep dorsal vein arterialization has been used successfully in selected patients. Aside from failure of the procedure and the occasional problems associated with vascular surgery, priapism and glans hypervascularization are specific complications of deep dorsal vein arterialization. Priapism in these cases is 'high-flow'; the functional arterial-cavernous fistula can overcome the maintenance of the flaccid state and cause persistent erection. Glans hypervascularization, a syndrome of glans enlargement, skin changes and pain secondary to excessive retrograde filling of the glans penis and corpus spongiosum, can result in urethral compression and glans ulceration. Along with the presentation of the case of a man who suffered both complications, we discuss their pathophysiology, prevention, and treatment.

Adult↗
PubMed1991

Hemodynamics of revascularization of the corpora cavernosa in an animal model. A preliminary report.

Numerous revascularization procedures are used for the treatment of vasculogenic impotence. In an animal model we created three different types of bypasses: inferior epigastric artery to dorsal penile artery, to dorsal artery and to dorsal vein (anastomotic arteriovenous fistula), and to dorsal vein alone. Epigastro-dorsal anastomoses remained fully patent without anticoagulants in 3 of 4 animals. With erection the flow in the inferior epigastric artery and the retrograde flow in the dorsal artery (towards the cavernous artery) increased significantly. In the 4 studies incorporating an anastomotic arteriovenous fistula we could not establish a clear reason to incorporate the artery; runoff was demonstrated only to the venous system. Arterial bypass to the dorsal vein with a simulated emissary vein increased outflow resistance as well as improved intracorporeal pressure during erection of the corpora in 4 animals. As resting pressure was also elevated, the penile smooth muscle might be at risk for further degeneration with this procedure.

Animals↗
PubMed1991

The sympathetic role as an antagonist of erection.

The effects of the lumbar and pelvic sympathetic system on penile erection were studied in a canine model. Erection was induced by cavernous nerve stimulation and detumescence by sympathetic trunk stimulation. Erection induced by cavernous nerve stimulation normally subsides slowly. After discontinuation of electrical stimulation the intracavernous pressure drops within a mean of 291 s to 50% and after a mean of 372 s to 10% of the highest level. However, stimulation of the sympathetic trunk at the level of L4-S1 applied directly after discontinuation of cavernous nerve stimulation accelerated this drop of intracavernous pressure significantly: to 50% after a mean of 19 s and to 10% after a mean of 36 s. If stimulation of the sympathetic trunk was initiated 20 s before cavernous nerve stimulation, the pressure rise was aborted completely. Neurostimulation of the hypogastric nerves alone or in combination with cavernous nerve stimulation did not change the intracavernous pressure. These results were not altered after neurotomy of the pudendal or hypogastric nerves. The main pathway of the fibers from the sympathetic trunk to the penis seems to run via the pelvic plexus. The stimulation voltage and frequency to induce erection or detumescence were equivalent. Our results suggest that an elevated central sympathetic tone may be one of the causes of psychogenic impotence.

Animals↗
PubMed1991

Extravaginal torsion of spermatic cord in adult.

A twenty-six-year-old man with no history of testicular trauma presented with both extra- and intravaginal torsion of the spermatic cord. This phenomenon is extremely rare in the adult, having been reported only twice before.

Adult↗
PubMed1991

Sympathetic inhibition of papaverine induced erection.

We studied the effect of neurostimulation of the lumbar sympathetic trunks on papaverine-induced penile erection in dogs and monkeys. The mean of 124 cm. H2O intracavernous pressure after papaverine injection was reduced under sympathetic trunk stimulation to 40.6 cm. H2O within a mean of 39 sec. In addition the flow of the internal pudendal artery was reduced indicating a decrease of the inflow to the penis. After the sympathetic stimulation was terminated, the intracavernous pressure increased again to the same level as before. This pressure recovery time was delayed after several sympathetic stimulations from 134 sec. (5 min. after papaverine injection) to at least 362 sec. (45 minutes after papaverine injection). Stimulation of the inferior hypogastric plexus had no effect on the intracavernous pressure. The neurostimulation range (3-4V; 20 Hz) was most effective in reducing the papaverine action on penile smooth muscles. The effect of sympathetic trunk stimulation seems to antagonize the relaxing action of papaverine on the cavernous smooth muscles and the cavernous arterioles. Our results imply that high sympathetic tone in some patients with psychogenic impotence may explain their poor response to intracavernous injection of papaverine.

Animals↗
PubMed1991

Penile detumescence: characterization of three phases.

In 22 dogs in which erection was induced by cavernous nerve stimulation, we analyzed the intracavernous pressure changes during detumescence without and with acute clamping of the aorta or electrostimulation of the lumbar sympathetic chains. Additionally, the degree of venous outflow obstruction was assessed by saline perfusion of the cavernous body during aortic occlusion. Detumescence had three distinct phases: an initial phase exhibiting a small pressure increase; a second phase showing a slow pressure decrease; and a third phase in which a fast decrease occurred. The first phase was abolished by aortic clamping, whereas the other phases were not significantly affected. Sympathetic stimulation abolished or prevented the second phase. Perfusion of the cavernous body during the second phase resulted in a pressure rise to off-scale values; however, when initiated during the terminal phase or in the nonstimulated penis, the pressure increase was slight. Our study indicates that the arterial flow rate influences the duration of the first phase of detumescence and that venous drainage is completely restored in the third phase. Furthermore, sympathetic stimulation causes an almost immediate full restoration of venous drainage, as cavernous perfusion initiated with an intracavernous pressure about twice as high as without sympathetic stimulation failed to increase pressure to off-scale values.

Animals↗
PubMed1991

Ultrastructural changes in impotent penile tissue: a comparison of 65 patients.

To determine whether impotence is caused by specific and consistent changes in erectile tissue, we compared the ultrastructure of the corpora cavernosa in 6 controls with that in 59 patients undergoing implantation of a penile prosthesis. The impotent patients were divided into groups based on a medical history of hypertension (10), pelvic surgery (9), alcoholic smokers (8), hypertensive alcoholics (3), hypertensive alcoholic smokers (3), smokers (3), diabetics (8), diabetic smokers (3), Peyronie's disease (3), spinal cord injury (3) and isolated causes (6). Our data demonstrate that different behavioral and/or medical conditions produce similar degenerative tissue responses. There is no single or specific cause of impotence that is manifest by consistent changes in erectile tissue.

Adult↗
PubMed1991

Reduction of sympathetic influences on penile erection by phentolamine.

The lumbosacral sympathetic trunks seem to play a major role in penile detumescence. In animal experiments an erection induced by cavernous nerve stimulation can be abolished by neurostimulation of the canine sympathetic trunks. This canine experiment was designed to study the possible reduction of the sympathetic effect by intravenous injection of phentolamine. The aborted erection by sympathetic trunks stimulation was partially antagonized by phentolamine. The arterial flow to the penis as well as the intracavernous pressure were elevated by this drug. As an expected side effect the systemic arterial blood pressure decreased by 4-14 cm H2O after phentolamine injection.

Animals↗
PubMed1991

Impotence after radical pelvic surgery: physiology and management.

Impotence has been a common problem after radical surgery of the colon, rectum, prostate, bladder, and seminal vesicle. However, a better understanding of the neuroanatomy of erection has resulted in its decline. When impotence does result, in cases where the extent of tumor involvement renders preservation of the neurovascular bundle impossible, the variety of treatments available is now improved: these include intracavernous injection of vasodilators, vacuum constriction devices, penile arterial and venous surgery, and penile prostheses. The improved understanding and management of impotence has greatly enhanced the quality of life of patients after radical pelvic surgery.

Erectile Dysfunction↗
PubMed1991

Hypertension and impotence.

In a group of 472 impotent patients who were evaluated with pharmacologic duplex sonography, 117 patient (24.8%) had a history of hypertension, 26 of them (22.2%) for more than 10 years. Objective data about the changes in pulsation, diameter and blood flow velocity of the penile arteries after papaverine injection and the resulting erectile response allowed indirect assessment of the penile venous function. Varying degrees of impaired arterial function were diagnosed in 85% of the patients. The duration of hypertension had less deteriorating effects on the penile arterial system than second risk factors such as diabetes mellitus (n = 31) or smoking (n = 26). Patients on antihypertensive medication (n = 88, 75.2%) demonstrated a worse arterial response to papaverine than those without medication (n = 29, 24.8%). The best vascular response to papaverine injection was found in patients taking a combination of beta-blockers and vasodilators (n = 6), whereas thiazides either taken alone or in combination (n = 51, 60%) seem to have a deteriorating effect on arterial function. However, the arterial response did not correlate with the ability to achieve 'full erection' after intracavernous papaverine injection. Clinical experience confirms that certain antihypertensive drugs affect not only the blood pressure, but also compliance of the erectile tissue resulting in a functional venous leak. This may impair erectile function as much as arteriosclerotic changes of the vascular system secondary to hypertension.

Antihypertensive Agents↗