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Biomedical subjects

R W Lewis

Publications and source records attributed to R W Lewis.

At least 73 records · Page 4Linked to original sources
PubMed1988

Correction of intrinsic penile chordee with a ventral penile graft of fascia lata.

Chordee is an abnormal curvature of the penis detected on erection. Congenital or primary curvature of the penis without hypospadias is, however, rare. There are two kinds of primary curvatures; those associated with a normal corpus spongiosum and those with a hypoplastic spongiosum. Secondary curvatures associated with Peyronie's disease or periurethral fibrosis associated with urethral stricture are more common in adults. Four nonhuman primates had successful correction of artificially induced chordee with a graft of fascia lata.

Animals↗
PubMed1988

Measurement of impotence by laser Doppler flowmetry and conventional methodology.

The problem of vasculogenic impotence was evaluated by laser Doppler flowmetry with the LD5000 capillary perfusion monitor to determine cutaneous penile blood flow in 25 men defined previously as impotent by Doppler ultrasound with penile brachial ratios of 0.63 +/- 0.14. Erotic visual stimulation for 1, 2 and 4 minutes did not statistically change the cutaneous flow as measured by laser Doppler flowmetry from its baseline of 20 mv. The dynamics of skin microcirculation in the penis may reflect changes in the deeper vessels and represent an alternate, dependable method to evaluate capillary perfusion.

Adult↗
PubMed1988

Venous surgery for impotence.

Venous surgery for impotence is in a dynamic state. The drainage of the corpora cavernosa normally occurs through the crural veins or the cavernous veins and the deep dorsal penile vein. Patients with drainage seen on cavernosography only into a superficial system that persists after injection of intracavernous vasoactive agents are likely to have good results if this drainage is eliminated. This type of patient is not common. A surgical approach that attempts to eliminate the deep dorsal penile system or the crural veins is not as successful. Perhaps subtle arterial disease, concurrent presence of neurologic disease, and collateralization all add to the significant failure rate. Many failures of spontaneous erection will, however, respond to intracavernous injection of vasoactive agents postoperatively. Deep dorsal vein arterialization probably should be reserved for those patients who have an arterial component to their impotence as well as a venogenic cause.

Erectile Dysfunction↗
PubMed1987

The fate of instilled pulmonary surfactant in normal and quartz-treated rats.

Naturally prepared radiolabelled pulmonary surfactant can be rapidly cleared from the alveolar surface to the lung tissue after intratracheal instillation into experimental rats. This clearance is both time- and dose-dependent, a large dose (10 mg/animal) becoming associated with lung tissue more rapidly than a smaller more physiological dose (0.75 mg/animal). The data indicate that extracellular dipalmitoyl-phosphatidylcholine, the major component of pulmonary surfactant, is not catabolized at the alveolar surface. Alveolar free cells (mainly macrophages) appear to play a minor role in surfactant clearance. Quartz-induced phospholipidosis does not lead to an alteration in the rate of bulk surfactant clearance from the alveolar surface, although the initial distribution of the removed phospholipid complex may change in relation to the enlarged heterogenous free cell population.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1987

Dynamic corpus cavernosography: effect of papaverine injection.

A study was done in 21 men to identify individuals with venous leakage as a cause of impotence. Combined pressure flow measurement and cinecavernosography were performed before and after the injection of papaverine into the corpora. After papaverine injection, erections and/or higher pressures occurred at lower flow rates in all the men. The venous drainage of the corpora decreased or disappeared in most subjects while the corpora became larger and contained more contrast material. The findings suggest that an active venous obstructive mechanism is important during erection, can be induced by the administration of papaverine, and should be evaluated in impotent men.

Adult↗
PubMed1987

Slow moving proteinase. Isolation, characterization, and immunohistochemical localization in gastric mucosa.

Human gastric mucosa contains three immunochemically distinguishable aspartic proteinases, pepsinogen I (pepsinogen A), pepsinogen II (pepsinogen C, progastricsin), and a nonpepsinogen proteinase also termed slow moving proteinase (SMP). The properties of SMP, and in particular its relationship to another aspartic proteinase, cathepsin D, were examined in this study. Slow moving proteinase and cathepsin D were isolated, respectively, from gastric mucosa and human spleen. Antiserum specific to each proteinase was prepared in rabbits. Rabbit anti-SMP did not recognize cathepsin D, and conversely, anticathepsin D did not react with SMP. Immunohistochemical studies localized SMP to surface epithelial cells in both the fundic and pyloric gland areas of the stomach. In contrast, cathepsin D was found mainly in mononuclear cells in the lamina propria and in parietal cells. Slow moving proteinase exhibited considerably lower Km values for its interaction with two chromogenic substrates than did cathepsin D. An even greater distinction between the two enzymes was found with the protein inhibitor from Ascaris lumbricoides; the activity of SMP was inhibited very strongly, whereas that of cathepsin D was not affected. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis under denaturing conditions, SMP consisted of two subunits with apparent molecular weights of 42,500 and 41,000. The last two properties characterize a less-well-known aspartic proteinase, cathepsin E. We conclude that SMP is not cathepsin D, but that it may be cathepsin E.

Cathepsin D↗
PubMed1987

Varicocele and its surgical management.

A discussion of the present role of varicocele in the management of the subfertile couple is presented, with emphasis on detection techniques and the increasing awareness of the presence of bilateral varicocele. The indications and techniques of surgical management are discussed, with particular emphasis on the use of the operating microscope to dissect the spermatic cord at the level of the external inguinal ring under local anesthesia on an outpatient basis with significant cost savings to the patient.

Ambulatory Surgical Procedures↗
PubMed1986

A method for preparing radiolabelled rat pulmonary surfactant.

A method is described for the preparation of rat pulmonary surfactant, radiolabelled specifically in the phosphatidylcholine species, which may be used for degradative studies of the lipoprotein complex. Intravenously administered [methyl-14C]choline chloride is maximally incorporated into alveolar surface surfactant 8 h after injection, and more than 97% of this radiolabel is present in the phosphatidylcholine fraction of the surfactant and, of this, 75% is associated with the dipalmitoyl phosphatidylcholine species. Electron microscopy indicates that the isolated surfactant has a similar physical form to that found at the alveolar surface. The mineral alpha-quartz can be used to increase the yield of surfactant lavaged from the lung surface, but the complex isolated from rats treated in this manner has a low specific radioactivity (less than 1000 d.p.m./mg) compared with that prepared from control animals (22860 d.p.m./mg).

Animals↗
PubMed1986

Vesicolithiasis.

Explore the source record for details and available documents.

Humans↗
PubMed1986

Another surgical approach for vasculogenic impotence.

Until recently, a defect in the capability of blood to be trapped in the corpus cavernosum so that adequate penile turgidity can be maintained for successful intercourse has not been considered a major etiology for impotence. A diagnostic test called dynamic cavernosography was developed that consists of a cine-taped cavernosogram in conjunction with intracavernous pressure measurements at 3 different cavernous infusion rates. The results of 104 of these tests are presented. More recently, 17 of these patients also have undergone papaverine tests. Of the patients 59 per cent had no or only partial erections at all infusion rates and pressure did not increase to greater than 50 mm. Hg. The papaverine test showed only partial or no tumescence when 60 mg. were injected into the corpora. As a result, 25 patients underwent a penile operation to remove some venous outflow channels. Of the patients who underwent an operation for absent tumescence at any flow rate and who had a large number of venous channels draining the corpora cavernosa on the cavernosogram 59 per cent were potent postoperatively.

Adult↗
PubMed1986

The effects of chronic cystitis on vesicoureteral reflux in an animal model.

The purpose of this study was to determine if chronic cystitis interferes with maturation of the ureterovesical junction, thus prolonging vesicoureteral reflux in infant rhesus monkeys (Macaca mulatta). Serial implantations of a Proteus-infested silastic pellet into the bladder wall ensured continued infection as demonstrated by urine culture. Chronic cystitis as evidenced by pathological findings at surgery and sacrifice was created in a group of infant monkeys who had initial spontaneous vesicoureteral reflux. There was no evidence of pyelonephritis. Four animals represent a short term study since they were followed from four months to one year of age. Three animals were long term studies and were evaluated for at least 21/2 years. In no animals did chronic cystitis delay the normal disappearance of vesicoureteral reflux that is commonly seen in these animals as the ureterovesical junction matures, as demonstrated by serial cystograms. In two animals reflux (after initial clearing) reappeared when a bladder calculus formed in these chronically infected animals. Renal damage occurred only in these animals. In conclusion, this animal model failed to demonstrate interference with normal vesicoureteral junction maturation in the face of a chronic bladder infection.

Aging↗
PubMed1986

Pathophysiology of varicocele in nonhuman primates: long-term seminal and testicular changes.

Varicocele was surgically induced in monkeys to study the long-term effects of the condition on seminal and testicular parameters. Sperm motility was depressed but improved after varicocelectomy. Sperm concentration was less affected, but sperm morphology showed long-term degenerative changes, i.e., for more than 2 years. Testicular blood flow was depressed acutely but returned to normal after 2 years. Electron microscopy showed changes in the basal lamina and spermatogonia that persisted throughout the study. Left adrenalectomy, at the time of varicocele induction, did not alter the development of varicocele-related changes. The sequence of changes suggests that the effects of this experimental varicocele may be reversed in the monkey model through changes in collateral and ancillary revascularization.

Animals↗
PubMed1985

The antigenic relatedness of proteins from human and simian prostate fluid.

Two-dimensional electrophoretic analysis of human prostate fluid reveals an abundant protein migrating to a molecular weight of 15 kD and an isoelectric point of 5.5. Polyclonal antibodies were raised specifically to microgram quantities of electrophoresed, excised, and eluted PSP15 (prostate secretory protein). Western immunoblot analysis using these antibodies showed they not only react to PSP15, but cross-react with simian prostate and human seminal fluid proteins of similar molecular weights. Two-dimensional gel immunoblots strongly suggest that the seminal protein and PSP15 are the same, thereby providing a more accessible source of the protein. The antibody to the human PSP15 cross-reacted with neither prostate fluid from the ventral lobe of the rat prostate nor the prostate fluid from the beagle dog.

Animals↗
PubMed1985

D-Tryptophan-6 analog of luteinizing hormone-releasing hormone as a protective agent against testicular damage caused by cyclophosphamide in baboons.

Possible protective effects of the agonist [D-Trp6]LH-RH (the D-tryptophan-6 analog of luteinizing hormone-releasing hormone) against testicular damage caused by cyclophosphamide (Cytoxan) were investigated in subhuman primates. Three adult male baboons (Papio anubis) were first subjected to normal semen evaluation by using electroejaculation. The average baseline count for the animals ranged from 95.7 X 10(6) to 585.7 X 10(6) sperm per ml with 90% normal forms and 85% motility with excellent rapid forward progression. After baseline evaluations, two of the animals were treated with daily subcutaneous injections of 0.5 mg of the agonist [D-Trp6]LH-RH. There was an initial rise in serum testosterone after 1 week, but testosterone fell to castration values at 1 month and continued at these levels during treatment with the agonist. There was also an initial rise in sperm concentration 1 month after treatment was started, but after 2 months the animals were azoospermic. After 13 weeks of therapy with [D-Trp6]LH-RH, these two baboons and a third untreated control animal were given cyclophosphamide at a dose of about 3 mg/kg of body weight per day for 4 months. The two animals pretreated with [D-Trp6]LH-RH, continued to receive this agonist until 1 week after the last dose of Cytoxan. In one of the two baboons treated with Cytoxan and the LH-RH agonist, the white blood count fell below 4000 per microliter, and the dose of Cytoxan had to be reduced to 1.5 mg/kg per day for 12 days. The control animal developed azoospermia after 4 months of treatment with cyclophosphamide, and serum testosterone increased while sperm count decreased. Four weeks after the agonist was stopped, serum testosterone in both animals pretreated with [D-Trp6]LH-RH returned to normal levels. The control animal showed a small amount of nonmotile sperm 2.5 months after cessation of treatment, but after 9 months remains oligospermic with poor sperm motility. In one of the animals treated with LH-RH agonist, semen analysis returned to normal pretreatment values 8 months after withdrawal of treatment. The other animal remains oligospermic 10 months after therapy, but the motility is improving. These preliminary results suggest that treatment with LH-RH agonist might decrease the gonadal damage caused by some chemotherapeutic agents.

Animals↗