Biomedical subjects

T F Lue

Publications and source records attributed to T F Lue.

At least 145 records · Page 8Linked to original sources

PubMed1993

Peyronie's plaque: surgical treatment with the carbon dioxide laser and a deep dorsal vein patch graft.

We describe a procedure for ablation of Peyronie's plaque using the carbon dioxide laser, which allows one to remove all palpable evidence of plaque while at the same time avoiding the creation of a large defect in the tunica albuginea requiring coverage with a large graft. The plaque is removed by making either a longitudinal or transverse incision in the plaque with a focused carbon dioxide laser beam from a hand held probe, and evaporating the plaque substance from the undersurface by tangentially directing the laser beam. It is possible to remove large dystrophic calcifications from within the plaque and to augment the repair in the area of greatest curvature using the deep dorsal vein as a patch graft. In cases of narrow plaques relaxation incisions and venous patch grafting alone are usually sufficient to correct the deformity. Our experience with 12 patients is summarized and 2 cases are reported in detail to illustrate the versatility of the procedure.

Aged↗

PubMed1993

Combined cavernous compression device and arteriovenous-cavernous fistula: a chronic canine model.

In 5 dogs studied over a 3-month period, we evaluated the chronic effects of the combination of deep dorsal vein arterialization with implantation of an inflatable venous compression device. The device was placed around the proximal corpora cavernosa, sparing the left dorsal artery. A left-to-right, end-to-side dorsal artery-dorsal vein fistula was fashioned, and the right dorsal vein was anastomosed to the corpus cavernosum as an end-to-side venocorporeal window. From postoperative day 15, the device was activated twice a day for 3 months. Intracavernous pressure (bilateral) and left dorsal artery blood flow were monitored, and the patency of the anastomoses was evaluated by vascular clamping, arteriography, cavernosography and microscopic dissection. The device was well-tolerated, requiring no anesthesia during activation. (A sixth dog developed glanular hyperemia and priapism and was excluded from evaluation). With cuff inflation, the intracavernous pressure was significantly higher on the experimental side (range, 20 to 106 cm. H2O higher; p = 0.028), and arteriography demonstrated contrast flowing in the fistula and window in 3 of 4 dogs in which it was done. Both clamping and microscopic dissection of the specimen showed patency of the anastomoses in all 5 dogs. Histologic examination revealed maintenance of normal cavernous tissue histology.

Anastomosis, Surgical↗

PubMed1993

Nitric oxide and cGMP: mediators of pelvic nerve-stimulated erection in dogs.

We sought to determine whether the L-arginine-nitric oxide-guanosine 3',5'-cyclic monophosphate (cGMP) pathway, known to mediate neurostimulation-induced smooth muscle relaxation in penile tissue of rabbits and humans in vitro, is operative also in vivo. Adult male dogs (n = 9) were subjected to direct electrical stimulation of the pelvic nerves to induce penile tumescence. Intracavernous injection of the nitric oxide-releasing substance S-nitroso-N-acetylpenicillamine resulted in similar tumescence. Intracavernous injection of a specific inhibitor of nitric oxide synthesis, NG-nitro-L-arginine, blocked pelvic nerve-stimulated tumescence, and this was partially reversed by intracavernous injection of the nitric oxide precursor L-arginine. Furthermore, neurostimulated tumescence was inhibited by methylene blue, an inhibitor of cytosolic guanylate cyclase and enhanced by M&B 22948, a cGMP phosphodiesterase inhibitor. These in vivo findings support the hypothesis that cavernous smooth muscle relaxation and penile tumescence are mediated by nitric oxide and cGMP.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1993

Cyclic guanosine monophosphate mediates penile erection in the rat.

Recent in vivo and in vitro studies suggest that nitric oxide or a nitric-oxide-like substance mediates nonadrenergic, noncholinergic relaxation of trabecular smooth muscle through activation of the cyclic guanosine monophosphate (cGMP) pathway. In 60 Sprague-Dawley rats, we investigated the effect of intracavernous administration of different drugs known to act at different levels of the cyclic adenosine monophosphate (cAMP) and cGMP pathways. Neither cAMP nor drugs that stimulate adenylate cyclase activity (vasoactive intestinal peptide, prostaglandin E1, calcitonin gene-related peptide) provoked any change in the basal intracavernous pressure. N-ethylmaleimide, an inhibitor of the enzyme adenylate cyclase, did not modify the response to electrostimulation of the cavernous nerve, indicating that the cAMP pathway does not play a significant role in penile erection in rats. However, intracavernous administration of methylene blue, a guanylate cyclase inhibitor, significantly reduced the response to electrostimulation (p = 0.001). Direct intracavernous injection of cGMP caused a statistically significant, dose-dependent increase in intravenous pressure that was not significantly inhibited by methylene blue. Sodium nitroprusside, a nitric oxide releaser and therefore a guanylate cyclase activator, caused a dose-dependent increase in intracavernous pressure (p < 0.05) that was inhibited almost completely by methylene blue (p = 0.002), supporting the theory that nitric oxide activates the synthesis of cGMP and that cGMP causes cavernous smooth muscle relaxation. Papaverine elicited an intracavernous pressure increase that was not affected by methylene blue or N-ethylmaleimide, indicating that papaverine acts through an independent pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗

PubMed1993

Drug-induced male sexual dysfunction. An update.

Impotence, defined as the consistent inability to maintain an erect penis of sufficient rigidity for sexual intercourse, has been estimated to affect 10 million American men. An age dependence has been shown to exist, with 25% of men over age 65 affected. A large body of clinical experience and published reports in the literature link many commonly prescribed drugs with sexual dysfunction. Drugs can affect sexual function at a variety of points such as inhibition of ejaculation or sedation/depression leading to reduced libido. Antihypertensive drugs have been most commonly associated with impotence. There have been reports of sexual dysfunction with almost all classes of antipsychotics, but little clinical investigation has been performed. Other drugs associated with sexual dysfunction include digoxin, clofibrate, cimetidine and various hormonal agents and antineoplastics. An important first step in approaching all impotent patients is the taking of a detailed medical, surgical, sexual and drug/substance abuse history. The least invasive form of therapy should be employed. Recent studies have shown intracavernous injections of alprostadil (prostaglandin E1) to be safe and effective for long term use. Vacuum constriction devices may also be of help. Better and more durable prostheses are now available should other treatment be unsuccessful.

Antihypertensive Agents↗

PubMed1993

In pursuit of the best candidates and procedures for penile revascularization.

Coronary bypass surgery to provide better blood flow to deficient areas of the heart is commonplace; the arteries of the heart in which blockage occurs are relatively large, and rerouting of blood is readily accomplished. In the penis, the internal pudendal system that provides arterial inflow can be easily bypassed when injury to a large vessel is the cause of erectile dysfunction. In the great majority of cases of penile arterial disruption, however, large-vessel disease cannot be demonstrated; the problem of low arterial flow originates within the corpora cavernosa, in the so-called helicine arteries. These arteries are very small, and are inaccessible unless the spongy erectile tissue of the corpora cavernosa is violated. In recent years, modest success has been reported in revascularizing the smaller arteries of the penis. The expert panelists in this symposium discuss the indications for such revascularization procedures, compare their techniques, and review the success rate in their work.

Adult↗

PubMed1993

Erectile dysfunction in men under 40: etiology and treatment choice.

We undertook a retrospective review of 100 impotent men under age 40 to determine the underlying etiologic factors in the group and to evaluate the role of surgery in their care. Although patients ranged in age from 18 to 40 (mean--32.2 years), the number of patients increased steadily with advancing years. The majority of patients (72) had vasculogenic impotence (arteriogenic--15, venogenic--46, mixed--11), followed by psychogenic (13), neurogenic (12) and other causes (4). The differential diagnosis did not correlate with age. Contributing factors were present in 76%, trauma and substance abuse being most common. Essentially equal numbers of patients were treated surgically (40) and with intracavernous injection of vasoactive agents (39). Considerably fewer had a vacuum constriction device (5), oral medication (5), psychotherapy (4), other therapy (4), and none (3). The majority of patients referred to our tertiary urologic practice for treatment of vasculogenic impotence were sent by other urologists. Although the referral source did not appear to influence the choice of treatment, it probably has accounted for the preponderance of vasculogenic impotence in this series.

Adolescent↗

PubMed1993

Sodium nitroprusside and neurostimulation cause increased levels of cyclic guanosine monophosphate and not cyclic adenosine monophosphate during canine penile erection.

We investigated the changes of cGMP and cAMP during penile erection induced by direct electrical stimulation of the pelvic nerve or sodium nitroprusside administration. Immediately after penile erection, the samples were put into liquid nitrogen and cyclic nucleotide content was measured. The results of these investigation suggest that both pelvic nerve stimulation and sodium nitroprusside induced penile tumescence. The total content of cGMP and not cAMP were significantly higher in treated samples as compared to control. SDS-polyacrylamide gel electrophoresis revealed several differences after treatment compared to untreated samples. This study demonstrated that the total content of cGMP and not cAMP increased after pelvic nerve stimulation and sodium nitroprusside treatment in penile tissue.

Animals↗

PubMed1993

Phenotypic and cytogenetic characterization of a human corpus cavernosum cell line (DS-1).

We report here the establishment and characterization of a corpus cavernosum cell line (DS-1) from human penile tissue. This is the first cell line of its type derived from cavernosum tissue. DS-1 cells have become immortalized in culture, and show growth in monolayers. These cells have a doubling time of about 45 h in in vitro culture. Cytogenetic analysis by G-banding demonstrated a diploid karyotype with a model chromosome number of 46. The chromosome constitution of DS-1 cells was found to be male (XY), in 28/30 cells scored. Two of the 30 cells showed an extra structurally rearranged "marker" chromosome, that appeared to be a derivative of chromosome 18 with excessive chromosome on the short arm. Ploidy analysis revealed that the majority of DS-1 cells had a DNA index of one. About 35% cells were found to be in G-1 phase and 52% cells in S phase. Light and electron microscopy of DS-1 cells and original penile tissue showed typical characteristics of this tissue. Immunocytochemistry studies using antibodies to smooth muscle actin, desmin, vimentin and cytokeratin (LP34, CAM5.2) showed that the DS-1 cell line had predominantly smooth muscle cells, as these cells were positive for smooth muscle actin, desmin and vimentin.

Cell Division↗

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↗