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Biomedical subjects

R W Lewis

Publications and source records attributed to R W Lewis.

At least 55 records · Page 3Linked to original sources
PubMed1995

Long-term results of penile prosthetic implants.

This article is intended to provide the implanting surgeon with information that can be used as a guideline for proper informed consent for the patient who is to have a penile prosthesis. The modern penile prostheses are quite reliable with an approximate 5% mechanical failure rate for the inflatable prosthesis after being in place for 5 years. Although approximately 90% of patients will have a functioning device at 5 years, only 70% will be completely satisfied with the device and this satisfaction rate is about the same for the partners. Late infection is possible and the use of prophylactic antibiotics during the time that infection risk might be possible is recommended.

Follow-Up Studies↗
PubMed1995

Comparison of RigiScan and sleep laboratory nocturnal penile tumescence in the diagnosis of organic impotence.

PURPOSE: We evaluated the relative use of RigiScan measurement of radial rigidity compared to sleep laboratory measurement of axial rigidity and trained observer determination of erectile function in the diagnosis of organic impotence. MATERIALS AND METHODS: A total of 28 patients underwent simultaneous 2-night formal sleep laboratory nocturnal penile tumescence and RigiScan monitoring. Standard normal values for radial rigidity and axial rigidity were tested for accuracy in predicting normal nocturnal penile tumescence compared to trained observer determination of the adequacy of an erection for penetration. RESULTS: RigiScan tip measurements correlated poorly with buckling pressure, while base measurements strongly correlated (p = 0.0005). Observer determination of a functional erection was strongly associated with tip (p = 0.002), base (p = 0.0005) and buckling pressure measurements (p = 0.0005). Using observer determination as the gold standard receiver operating curves were generated to select RigiScan base and buckling pressure measurements that predicted functional erections with the highest sensitivity and specificity. CONCLUSIONS: RigiScan is a useful tool for measuring nocturnal penile tumescence. However, base measurements are more accurate than tip measurements for evaluating erectile function. The currently accepted level of rigidity used to define a normal erection (70% or greater) overestimates organic erectile dysfunction.

Adult↗
PubMed1994

Infertility.

Explore the source record for details and available documents.

Autoantibodies↗
PubMed1994

Diagnosis and treatment of vasculogenic impotence.

In this review the authors discussed the diagnosis and treatment of vasculogenic impotence. They evaluate the different diagnostic methods and treatment possibilities for the everyday clinical practice. The surgical procedures need to be done by qualified specialists who are familiar with penile anatomy and trained in microvascular surgical techniques.

Humans↗
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↗
PubMed1992

Methylene chloride--an inhalation study to investigate pathological and biochemical events occurring in the lungs of mice over an exposure period of 90 days.

Male B6C3F1 mice were exposed to 4000 ppm methylene chloride (MC) for 6 hr/day, 5 days/week for up to 13 weeks. Groups of mice were killed at intervals from Day 2 to Week 13. Whole lungs were examined morphologically, immunocytochemically, and biochemically. Biochemical and morphological examination was also performed on isolated Clara cells. The major initial morphological effect seen in lungs was acute Clara cell damage after one exposure to MC. However, this damage appeared to resolve after five consecutive daily exposures to MC. After a 2-day interval the Clara cell lesion reappeared on subsequent reexposure to MC. However, the severity of the lesion decreased over the duration of the study. The appearance and disappearance of the lesion in the Clara cell correlated well with the activity of cytochrome P450 monooxygenase in the Clara cell as assessed immunocytochemically (cytochromes P450IIB 1 and 2) in the whole lung and biochemically in the freshly isolated Clara cell (determined by ethoxycoumarin O-dealkylation and aldrin epoxidation). When there was a marked decrease in cytochrome P450 monooxygenase activity the lesion was not present. This suggested that with time the lung (Clara cell) has developed tolerance to MC possibly due to the inactivation of a cytochrome P450 isozyme. The glutathione S-transferase metabolism of MC by the lung cytosol remained virtually unaltered throughout the study. Events accompanying the discussed changes include (1) a significant increase in nonprotein sulfhydryl in the lungs of all exposed animals, (2) altered plating characteristics of the isolated Clara cells from exposed lungs after 24 hr in culture, and (3) an increase in the number of bronchiolar cells in the S-phase after the first exposure to MC. The study also demonstrates the advantages of target cell isolation and study over whole lung biochemical investigation alone.

Administration, Inhalation↗
PubMed1992

Value of the Candida antigen assay in diagnosis of systemic candidiasis in burn patients.

The Cand-tec latex agglutination test was used to analyze 2,575 serum samples from 47 consecutive burn patients at risk for systemic candidiasis and serum samples from 24 nonhospitalized control subjects. One burn patient had systemic candidiasis documented by culture of a deep biopsy specimen. In addition, blood culture produced positive results in one patient with no other evidence of systemic candidiasis. Wound, sputum, mucous membrane, or gastrointestinal tract specimens were cultured in 25 of 47 (53%) patients with no evidence of systemic candidiasis. Surveillance cultures were negative in 19 (40%) patients and there were no signs of systemic candidial infection. The sensitivity of the Candida antigen titer was 100% at titers of greater than or equal to 1:2, greater than or equal to 1:4, greater than or equal to 1:8, and greater than or equal to 1:16. Specificity was 77% at titers of greater than or equal to 1:4, 94% at titers of greater than or equal to 1:8, and 100% at titers of greater than or equal to 1:16. The positive predictive value ranged from 6.0% at greater than or equal to 1:4 to 100% at greater than or equal to 1:16. The negative predictive value was 100% for all titer values. The Cand-tec antigen test shows poor specificity and poor positive predictive value for the detection of systemic candidiasis in burn patients.

Adolescent↗
PubMed1992

Management of corporal veno-occlusive dysfunction.

Veno-occlusive dysfunction has become a recognized cause of organic impotence. The existence of concomitant arterial and sinus smooth-muscle disease makes this disorder often difficult to diagnose. It rarely can be the sole etiology for impotence. The authors' experience in the treatment of this disorder in over 100 patients is presented. The authors rely on cavernosometry/pharmacocavernosometry/pharmacocavernosogr aphy and the color duplex Doppler screening test (to eliminate concomitant arterial disease) as the primary diagnostic tools. Twenty-two patients of 58 (38%) have achieved long-lasting success from the surgery so that they are able to have vaginal intercourse. Another 12 patients (21%) have been improved but must depend upon pharmacological injection therapy to obtain a sufficient erection for intercourse. There has been a 41% failure rate, and these are discussed.

Arterial Occlusive Diseases↗
PubMed1992

An in vitro model for studying the effects of slime and nonslime-forming Staphylococcus epidermidis contamination of intravenous catheters.

An in vitro model was developed to study the relationship between intravenous catheters, bacteria, and the subcutaneous tunnel. Studies of both slime-forming and nonslime-forming coagulase negative Staphylococcus epidermidis show that slime formation enhances capillary action of coagulase negative S. epidermidis. This offers a possible explanation of the increased virulence associated with slime-forming coagulase negative S. epidermidis in the clinical situation.

Agar↗
PubMed1991

Results of surgery for veno-occlusive disease.

Surgery directed at veno-occlusive dysfunction in impotency has evolved since 1981, following the recognition that vascular disorders are the major source of etiology of impotency. As the diagnostic tests for concomitant arterial disease have become more sophisticated, the results for pure veno-occlusive surgery have improved. Details of postoperative results in 60 of the author's patients are discussed along with other published results. The failure rate is 30-50%. Success includes those patients who can then obtain an erection with pharmacological agents who were unable to do so prior to surgery. A discussion of why the surgery fails is presented.

Erectile Dysfunction↗
PubMed1991

Vasculogenic impotence. Duplex and color Doppler imaging.

Varicoceles, although only occasionally symptomatic, are reported to occur in 20% to 50% of infertile or subfertile men. Ligation or occlusion of the spermatic vein in these patients has improved semen quality in many instances. Recently, it has been recognized that varicoceles can be bilateral or subclinical and thus detected only by imaging. Sonographic diagnosis of varicoceles and percutaneous occlusive therapy are reviewed in this article.

Color↗
PubMed1990

Clara cell cultures from the mouse and their reaction to bronchiolar toxins.

The major aim of this study was to determine if small numbers of freshly isolated mouse Clara cells could be used to rapidly screen the toxic effects of a number of diverse pulmonary toxins. A short-term (20 hr) culture of functionally competent (nitotetrazolium reductase positive) Clara cells was developed. In this culture the Clara cells were allowed to attach to an extracellular matrix in 96-well multiwell plates containing a culture medium of DCCM 1 and Ultroser G (0.4%). Pulmonary toxins (a total of 26 agents with concentrations ranging from 10(-7) M to 10(-3) M) were examined for their ability to reduce the attachment efficiency of functionally competent Clara cells and TD50 values (the amount of toxin required to reduce normal attachment efficiency by 50%) were calculated. With the possible exception of some halogenated hydrocarbons, the simple toxicity test in vitro correlated well with the known effects of the bronchiolar necrotic agents in vivo. For 13 compounds studied there was a direct correlation between TD50 values in vitro and LD50 values (mostly oral) in rodents in vivo, the correlation coefficient of the regression line being 0.783.

Animals↗
PubMed1989

Duplex and color Doppler sonographic evaluation of vasculogenic impotence.

One hundred eighty patients with suspected vasculogenic impotence were evaluated with conventional penile duplex sonography with spectral analysis and color Doppler imaging. Measurements of mean peak systolic and end-diastolic velocities were obtained from the cavernosal arteries before and after intracavernosal injections of papaverine. Sixty-one patients were examined with dynamic cavernosography and cavernosometry, and 12 patients were studied with selective internal pudendal and penile arteriography. All five patients with abnormal arteriography had mean peak systolic velocities in the cavernosal arteries of less than or equal to 25 cm/sec (sensitivity, 100%; 95% confidence interval, 48-100%) after the injection of papaverine. Six of the seven patients with normal arteriography had mean peak systolic velocities of greater than 25 cm/sec (specificity, 85.7%; 95% confidence interval, 42-100%) after injection of papaverine. By using data from a receiver-operating-characteristic curve, we determined that end-diastolic velocities in the cavernosal arteries of greater than or equal to 5 cm/sec after the injection of papaverine correctly identified patients with excessive venous leakage on cavernosometry; the sensitivity was 90% (95% confidence interval, 77-97%) and the specificity was 56% (95% confidence interval, 30-80%). The addition of color Doppler sonography made the detection of vessels easier and the correction of the Doppler angle more accurate, resulting in more rapid and accurate acquisition of data. Penile duplex sonography with spectral analysis and color Doppler imaging are sensitive and noninvasive means of examining patients with potential vasculogenic impotence.

Adolescent↗