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T F Lue

Publications and source records attributed to T F Lue.

At least 127 records · Page 7Linked to original sources
PubMed1994

The distribution of elastic fibrous elements within the human penis.

OBJECTIVE: To determine the distribution of elastic fibres in the tunica albuginea and the erectile tissue of the penis. MATERIALS AND METHODS: Samples of tunica albuginea or penile erectile tissue were taken from seven cadavers and five patients undergoing surgery. Light and electron microscopy were performed. RESULTS: There were two anatomical regions in which elastic fibres were seen rarely: the proximal crus and the distal tunica. In the rest of the corpora cavernosa where the tunica was more compliant, the elastic fibres were in relative abundance. In the corpus spongiosum, abundant irregularly oriented elastic fibres were present; the densest elastic network was found in the glans penis and was composed of coarse elastic fibres. A perisinusoidal fibroelastic shell was seen in the glans, which was probably an extension of Buck's fascia. The elastic components within the sinusoids (cavernosal, spongiosal, and glanular) were similar but finer than the elastic lamellae in the penile arterial wall. CONCLUSION: The elastic fibres were unevenly distributed, often forming an irregular network on which the collagen component rested. Elastic fibres were more abundant in the corpus spongiosum, around the blood vessels and surrounding the sinusoid of the corpus cavernosum.

Collagen↗
PubMed1994

Rat model for the study of penile erection: pharmacologic and electrical-stimulation parameters.

We report the use of a modified rat model for the study of the mechanisms of penile erection. In 92 Sprague-Dawley rats, the cavernous nerve was stimulated with different pulse intensities and frequencies, and the intracavernous pressure, time to maximal pressure and total duration of tumescence were measured. A maximal response was elicited at 20 pulses per second (pps) and 1.5 mA. Using this as 100%, we determined the relative pressure responses obtained with other frequencies: 5 pps, 57.3% (p = 0.007), 10 pps, 84.9% (p = 0.043); 30 pps, 99.5% (p = 0.832); 40 pps, 97.8% (p = 0.168); 50 pps, 90.9% (p = 0.021); 100 pps, 76.1% (p < 0.001). The time to maximal pressure varied with different frequencies, but was in all cases significantly different from the 20-pps response. Erection time during continuous cavernous nerve stimulation was significantly longer with frequencies below 20 pps (10 and 5 pps). In 30 rats, the physiologic response to intracavernous injection (0.03 ml) of acetylcholine, atropine, guanethidine, norepinephrine, phenylephrine, papaverine, terbutaline (intravenous also) and phentolamine was measured. Papaverine caused a dose-dependent rise in pressure; acetylcholine, atropine (a parasympathetic blocking agent) and guanethidine all had minimal effects. Phentolamine and norepinephrine increased systemic blood pressure, whereas phenylephrine decreased the intracavernous pressure in response to electrostimulation significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1994

Organic impotence.

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1994

Erectile dysfunction.

A better understanding of penile physiology and pathophysiology has revolutionized the diagnosis and treatment of erectile dysfunction in the past decade. This article summarizes the current knowledge and presents a patient's goal-directed approach to the evaluation and treatment of erectile dysfunction.

Erectile Dysfunction↗
PubMed1993

Nitric oxide synthase: a new diagnostic tool for neurogenic impotence.

Cavernosal biopsy specimens obtained from men undergoing penile surgery permitted determination of the diagnostic value of nitric oxide synthase in neurogenic impotence. In biopsy specimens obtained from 25 men, the presence of nitric oxide synthase (NOS), as shown by nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining, was determined in nerve fibers, smooth muscle, and sinusoidal endothelium. Positive staining for NOS correlated significantly (p < or = 0.001) with a clinical history of cavernous nerve integrity. In comparison, staining with protein gene product (PGP 9.5), an excellent general nerve stain, lacked any degree of specificity as an indicator of nerve status. NADPH diaphorase may provide important insight into the cavernous nerve integrity of the patient. This report is the first to describe histologic features of human cavernosal tissue biopsies that will allow the direct diagnosis of neurogenic impotence owing to cavernous nerve damage.

Amino Acid Oxidoreductases↗
PubMed1993

Pathophysiology of erectile dysfunction.

During the past decade, our knowledge of the hemodynamics, functional anatomy, neurophysiology, and neuropharmacology of erectile function has evolved substantially. The change of smooth muscle tone has emerged as a key factor in erection and detumescence. However, future studies are needed to elucidate the cellular and molecular basis of erectile physiology. With insight into normal physiology we will understand the pathologic process and be able to treat it.

Animals↗
PubMed1993

Calcitonin gene-related peptide: possibly neurotransmitter contributes to penile erection in monkeys.

The distribution of calcitonin gene-related peptide (CGRP) immunoreactivity in the cavernous tissue and the erectile response to intracavernous injection of CGRP was investigated in 7 monkeys. Intracavernous CGRP increased cavernous arterial flow and induced cavernous smooth muscle relaxation and venous outflow occlusion. Intracavernous injection of CGRP antibody did not significantly change the erectile response to cavernous nerve stimulation. Histologic staining for CGRP immunoreactivity showed nerve fiber-like staining within the cavernous arterial wall and the cavernous smooth muscles. These data suggest that CGRP may contribute to penile erection in monkeys.

Animals↗
PubMed1993

Peyronie's disease: a modified treatment.

We evaluated 93 patients with complaints of sexual dysfunction and evidence of Peyronie's disease. Duplex ultrasonography (10-MHz probe and 4.5-MHz pulsed Doppler test) in 87 enabled definition of their penile vascular response to an intracorporeal injection of a vasoactive agent. Vascular disease was present in 70 percent of the study population. Forty-four patients had a surgical procedure. Nineteen had plications using a simultaneous pharmacological erection, 3 had dermal grafts, and 3 with severe vascular disease had primary placement of a prosthesis. One patient underwent a single Nesbit procedure. In 18 patients, we incised the plaque and grafted a segment of the deep dorsal vein, using the expertise gained from penile venous surgery. In the vein-grafted patients, rapid return of suppleness of the penile shaft, use of only a single incision, and use of the patient's own tissue, with the possible beneficial effect of endothelial-derived substances (nitric oxide) decreasing the risk of hematoma below the graft, support our belief that this modified technique may be superior to those presently in common use.

Adult↗
PubMed1993

Anatomy of cavernous nerves distal to prostate: microdissection study in adult male cadavers.

Retrograde and antegrade dissections from the penile hilum to the prostatic area and the glans penis were performed in 4 formalin-preserved adult male cadavers. In addition to the medial branches accompanying the urethra, the lateral branches of the cavernous nerves pierced the urogenital diaphragm 4 to 7 mm from the striated muscles of the external sphincter. At the penile region, multiple communications between the cavernous and dorsal nerves were noted that suggest that either the cavernous nerves use the dorsal nerve as a carrier to the distal portion of the penis or the dorsal nerve may itself contain autonomic fibers. These findings will improve our ability to preserve erectile function during pelvic, urethral, and penile surgery.

Adult↗
PubMed1993

Intracavernous sodium nitroprusside: inappropriate impotence treatment.

On the basis of reports describing nitric oxide as a form of endothelium-derived relaxing factor and on our own experience with intracavernous use of nitric oxide-releasing substances in animal models, we undertook an approved human study of intracavernous sodium nitroprusside as a treatment for impotence. We report our early experience in which severe hypotension and only mild tumescence in our first 3 patients caused us to discontinue the trial.

Aged↗
PubMed1993

High flow priapism: a spectrum of disease.

We describe 4 cases of high flow arterial priapism, ranging from 1 week to 3 years in duration. The mode of presentation, evaluation using a duplex scanner, treatment and ultimate resolution are discussed. In 1 patient treated with ice compression the erection subsided spontaneously. One patient underwent percutaneous embolization and achieved detumescence. In 2 men a vascular pseudocapsule formed around the site of the ruptured cavernous artery that provided an important anatomical landmark for intraoperative localization. The ruptured branch of the cavernous artery was ligated in an open procedure. Based on these cases and a review of the literature, we outline a modified diagnostic and therapeutic approach for patients with high flow arterial priapism.

Adolescent↗
PubMed1993

Can a venous patch graft be a substitute for the tunica albuginea of the penis?

We describe our experience with plaque excision and placement of a venous patch graft. Sprague Dawley rats (n = 20) underwent excision of a wedge of tunica albuginea with the defect covered by a segment of detubularized femoral vein, endothelial side towards the cavernous tissue. Erectile function, as determined by the rise in intracavernous pressure with cavernous nerve stimulation (mean 54.0 +/- 4.2 cm. H2O), was equal to that in a group of 10 intact age-matched controls (mean 46.9 +/- 3.37 cm. H2O). Penile cross-sections stained with Hart's elastic fiber stain or Trichrome stain revealed only minimal fibrosis in the region of the patch. In 3 dogs, a wedge of tunica was removed, and the defect was covered with a segment of detubularized deep dorsal vein. When sacrificed at 3 months, all animals had retained their erectile function with histologic evidence of minimal fibrosis. On the basis of histologic and functional data, the venous patch appears to be a reasonable alternative substance to those in common use.

Animals↗
PubMed1993

A prostaglandin E1 dose-response study in man.

Because prostaglandin E1 causes erection by smooth muscle relaxation in a receptor-dependent manner, one would expect increasing dosages to cause a progressively greater response and that, at receptor saturation, further increases would not be beneficial. To test this hypothesis a single-blind, placebo-controlled study of increasing dosages of prostaglandin E1 injected intracavernously was done. In 16 men with vasculogenic impotence erections were monitored by the RigiScan device in real time for 2 hours after injection, and rigidity, tumescence and duration of erection were measured. Summary parameters to characterize erection with each dosage were developed: maximal rigidity, maximal rigidity sustained for 30 minutes and duration of greater than 60% rigidity. The dose-response curve was similar for all 3 parameters. The initial response to escalating doses of prostaglandin E1 from 2.5 to 20 micrograms. demonstrated a steep dose-dependent increase; at greater than 20 micrograms. a plateau was reached, indicating a nonlinear response. More than 80% of the patients attained the maximal response at doses of 20 micrograms. or less and less than 20% benefited from a further increase. Based on these results, the effects of prostaglandin E1 appear to be receptor-dependent and prostaglandin E1 monotherapy for impotence could be limited to 20 micrograms. or less, since larger amounts offer little additional benefit.

Alprostadil↗
PubMed1993

The role of cyclic adenosine monophosphate, cyclic guanosine monophosphate, endothelium and nonadrenergic, noncholinergic neurotransmission in canine penile erection.

To elucidate the neuropharmacology of erection, we undertook an in vivo canine study to examine the role of cholinergic and nonadrenergic, noncholinergic (NANC) neuroeffectors and the sinusoidal endothelium in erection induced by electrostimulation. We also examined the effect of adenylate cyclase and guanylate cyclase blockers by intravenous injection of N-ethylmaleimide and methylene blue, respectively. In addition, the effects of intracavernous injection of the nitric oxide-releasing substance, nitroprusside, and bromocyclic adenosine monophosphate (AMP) and bromocyclic guanosine monophosphate (GMP) were also studied. In contrast to in vitro results, atropine reduced the increase of intracavernous pressure after neurostimulation (p = 0.029). Intracavernous injection of CHAPS to destroy the sinusoidal endothelium abolished the response to acetylcholine (p = 0.001), but only partially inhibited the response to electrostimulation (mean = 75% pressure increase, p = 0.022), indicating that neuronal nitric oxide plays a major role in penile erection. Methylene blue, a guanylate cyclase inhibitor, significantly inhibited the erectile response to both neurostimulation and sodium nitroprusside (p = 0.000 and 0.017, respectively). However, N-ethylmaleimide, an adenylate cyclase inhibitor, could not reduce the response to neurostimulation (p = 0.078). The erectile response to intracavernous injection of cGMP was significantly better than that induced by cAMP (p = 0.025). Our results suggest that both the cholinergic and NANC neuroeffectors and the sinusoidal endothelium are involved in erection. In addition, our data imply that the neuronal nitric oxide/cyclic GMP system is the most likely pathway for penile smooth muscle relaxation and erection.

Animals↗
PubMed1993

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

A prosthetic penile venous compression device was surgically placed in 14 dogs to assess the effects of chronic device implantation and repeated device cycling on cavernous tissue. Duration of device implantation ranged from 37 to 224 days; total number of device cycles ranged from 8 to 59. At recovery, erection was induced by electrostimulation of the pelvic nerve. The device successfully prolonged intracavernous elevation for as much as 30 minutes after inflation. Histologic examination of representative tissue sections through the corpora revealed no evidence of neural injury, vascular compromise, or tissue atrophy. The implantable venous compression device may offer an improved method of treatment of venogenic impotence.

Animals↗
PubMed1993

Posttraumatic impotence: magnetic resonance imaging and duplex ultrasound in diagnosis and management.

In 15 patients, impotent as a result of prostatomembranous urethral disruption consequent to pelvic crush injuries, magnetic resonance imaging (MRI) and duplex ultrasound were used to establish anatomical and pathophysiological criteria for accurate diagnosis and appropriate management. All patients were initially treated by suprapubic cystostomy diversion for at least 3 months, after which urethral reconstruction was performed. All men were potent before the pelvic trauma, with loss of sexual function immediately thereafter. Preoperative MRI demonstrated prostatic displacement in 13 cases (86.7%) and cavernous injury in 12 (80%). Duplex ultrasound revealed the cause of erectile failure as vasculogenic in 12 patients (80%) and neurogenic in 3 (20%). Treatment of impotence was deferred for at least 18 months after injury. Of the neurogenic group 2 patients were started on intracavernous injection therapy and 1 refused treatment. Of the vasculogenic group 3 patients underwent successful revascularization, 2 are on injection therapy and 1 had a penile prosthesis inserted. The detailed anatomical information obtainable with pelvic MRI and the functional data provided by duplex ultrasonography enabled us to identify the individual organic components of posttraumatic impotence and to select effective cause-specific therapy.

Adolescent↗
PubMed1993

Intracavernous pharmacotherapy for impotence: selection of appropriate agent and dose.

We performed a retrospective analysis of 101 impotent patients using intracavernous self-injections as primary therapy for vasculogenic impotence. A total of 70 patients used an average of 5.58 micrograms prostaglandin E1 (95% confidence interval 4.83 to 6.34 micrograms) as a single agent, and 31 injected 0.40 ml. (95% confidence interval 0.342 to 0.457 ml.) of a combination of papaverine (12 mg./ml.), phentolamine (1 mg./ml.) and prostaglandin E1 (9 micrograms/ml.). We describe the procedure to establish the dosage for home use and discuss the implications of the low dosages relative to previous reports.

Adult↗