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Biomedical subjects

S K Wilson

Publications and source records attributed to S K Wilson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Long-term results with Hydroflex and Dynaflex penile prostheses: device survival comparison to multicomponent inflatables.

PURPOSE: We compared our experience with self-contained inflatable and multicomponent prostheses during similar intervals. MATERIALS AND METHODS: We followed 295 patients with self-contained prostheses and 1,026 with multicomponent inflatable devices for up to 8 years. Revision rates for mechanical failure, infection or patient dissatisfaction were statistically analyzed. RESULTS: Multicomponent inflatable prostheses were superior with regard to mechanical reliability and patient satisfaction, with no differences in rate of infection. Self-contained prostheses were best replaced with the AMS 700CX device, thus avoiding aneurysm. CONCLUSIONS: Self-contained inflatable prostheses may be of limited value for the treatment of impotence. The AMS 700CX is the device of choice for replacement of explanted self-contained prostheses.

Follow-Up Studies↗
PubMed1996

Prevention and treatment of complications of inflatable penile prosthesis surgery: a review article.

Over the last 16 years more than 3,000 procedures involving multi-component inflatable penile prosthesis have been performed. A variety of types of complications have been encountered, including mechanical problems with the prosthesis, intraoperative complications, postoperative complications, problems with infection and patient dissatisfaction. During the course of this experience we have made some observations and developed techniques to minimize and treat the complications seen with both routine and difficult inflatable penile prosthesis implantation surgery.

Humans↗
PubMed1995

The measurement of maltreatment: a comparison of approaches.

This study examined the comparability and predictive validity of three approaches to the measurement of child maltreatment. Adolescents (N = 160, aged 11-17) were randomly selected from the open caseload of a child protection agency. Global ratings of maltreatment severity were made by three reporting sources: researchers on the basis of protection agency case files, protection agency social workers, and the adolescents themselves. Ratings were made of five types of maltreatment: physical, sexual, emotional, neglect, and exposure to family violence. Self-reported (YSR) and caretaker-reported (CBCL) adjustment measures were also obtained for each subject. Results indicated that over 90% of the sample had experienced more than one type of maltreatment. Comparison of ratings across sources indicated considerable disagreement with respect to judgments of maltreatment occurrence and severity. Relative to professional ratings, adolescent ratings were better predictors of externalizing and internalizing symptomatology in both univariate and multivariate analyses.

Adolescent↗
PubMed1995

Inflatable penile implant infection: predisposing factors and treatment suggestions.

A retrospective review of 1,337 consecutive inflatable prosthesis implantations was done to detect predisposing factors for infection. Operations were performed by the same team during a 7-year period. Of the procedures 823 were primary implantations, while the remaining 514 were either revisions (mechanical failure, iatrogenic causes or patient dissatisfaction), salvage operations or removals for infection. The etiology of impotence as a predisposition for infection in primary implantations was significant for spinal cord injury (9% of the cases) and steroid use (50%). Diabetes had a statistically insignificant 3% risk of infection, with all other causes having a 1% infection rate. A total of 428 revisions was performed with an overall infection rate of 10%. Rates of infection ranged from 8% in nondiabetics to 18% in diabetics requiring revision. Staphylococcus species were the most commonly cultured organisms. Salvage operations (29 cases) of several types were attempted for infected prostheses. Our results with salvage were poor and we currently routinely remove the entire prosthesis for infection except in cases of urethral erosion of 1 cylinder.

Causality↗
PubMed1995

A personal approach to the management of the complications of penile implant surgery.

Over the last 16 years more than 3000 procedures involving multi-component inflatable penile prostheses have been performed. A variety of types of complications have been encountered, including mechanical problems with the prostheses, intraoperative complications, postoperative complications, problems with infection and patient dissatisfaction. During the course of this experience we have made some observations and developed techniques to minimize and treat the complications seen with both routine and difficult inflatable penile prosthesis implantation surgery.

Humans↗
PubMed1994

Single-dose bioavailability of two extended-release lithium carbonate products.

The single-dose bioavailabilities of two extended-release lithium carbonate products and an immediate-release product were compared. Nonsmoking healthy volunteers ages 20-31 (n = 12) were randomly assigned to one of three groups and given three treatments, each separated by a one-week period. The treatments, which were given to each group in a different sequence, consisted of three 300-mg immediate-release lithium carbonate tablets (Lithotab), two 450-mg extended-release lithium carbonate tablets (Eskalith CR), and three 300-mg extended-release lithium carbonate tablets (Lithobid). Blood samples were collected just before drug administration and at intervals up to 48 hours afterward. Urine was collected for 96 hours. Plasma and urine lithium concentrations were determined by flame-emission spectrophotometry, and lithium pharmacokinetic values and the cumulative urinary excretion of lithium were computed. Mean maximum plasma lithium concentration (Cmax) differed significantly among all three lithium carbonate products. Eskalith CR produced a 40% lower Cmax and Lithobid a 25% lower Cmax than Lithotab; Lithobid produced a 23% higher Cmax than Eskalith CR. Lithotab had a significantly shorter mean time to maximum plasma lithium concentration than either extended-release product. Mean cumulative urinary excretion of lithium did not differ significantly among the three products. Two extended-release lithium carbonate products were not bioequivalent when given in single doses to healthy volunteers.

Adult↗
PubMed1994

A new treatment for Peyronie's disease: modeling the penis over an inflatable penile prosthesis.

We treated 138 patients with severe Peyronie's disease by insertion of an inflatable penile prosthesis and manual modeling of the erect penis. This novel technique was successful in 118 patients (86%) in achieving a straight, rigid erection. In 11 patients (8%) penile modeling did not result in satisfactory straightening and relaxing plaque incisions were performed. Complications of penile modeling included urethral perforation in 4 patients (3%). Infection of the prosthesis occurred postoperatively in 4 patients (3%). At a mean followup of 32 months (range 9 to 84) 124 patients (90%) were actually using the penile prostheses and none reported penile shortening or impairment of glandular sensation. We suggest that penile modeling over an inflatable penile prosthesis is an important new technique for the patient with severe Peyronie's disease.

Adult↗
PubMed1994

Isolated, perfused rabbit ear artery: a model for studying segmental vasoconstriction and dilatation.

Severe increases in blood pressure (BP) are associated with a segmental pattern of constriction and dilatation in small arteries and arterioles, but the pathogenesis is poorly understood. We showed that the isolated, perfused rabbit ear artery typically develops segmental constriction and dilatation when intraluminal pressure is > 160-180 mm Hg during field stimulation of perivascular nerves (> 6 Hz) or extra- or intraluminal infusions of norepinephrine (NE > 10(-7) M) or phenylephrine (PE) (> 5 x 10(-7) M). Light, transmission, and scanning electron microscopy showed that the dilated vessel segments initially show endothelial injury with no smooth muscle lesions. After repeated or prolonged exposure to high intraluminal pressure, dilated segments manifest extensive and severe endothelial and smooth muscle damage. Dilated regions also became abnormally permeable to tracer particles (ferritin). Constricted segments did not show evidence of endothelial or smooth muscle injury or hyperpermeability. These changes, i.e., segmental vasoconstriction/dilatation, hyperpermeability, and vessel wall damage localized to dilated segments, are comparable to those that occur in small arteries and arterioles during severe hypertension. We discuss the potential usefulness of the isolated ear artery as a model for studying the pathogenesis and morphology of segmental vasoconstriction/dilatation.

Animals↗
PubMed1993

Double-blind placebo controlled randomized trial of indomethacin on urodynamic values measured by radionuclide imaging.

The effect of the prostaglandin synthetase inhibitor, indomethacin on urodynamic values measured by radionuclide imaging was studied in 17 men in a double-blind placebo controlled randomized trial. Measurements were made of voiding time, time for 50% emptying, average flow rate, ejection fraction, post-void residual urine volume, voided volume, and total bladder volume. Statistical analyses indicated no placebo-indomethacin differences between the two groups. Although prostaglandins are thought to contribute to the act of micturition by maintenance of bladder tone and contractility, our studies indicate that a standard dose of the prostaglandin inhibitor, indomethacin, did not affect the voiding component of bladder function. Patients need not discontinue prostaglandin inhibitors and other non-steroidal anti-inflammatory drugs with such effects prior to urodynamic testing.

Aged↗
PubMed1991

Peripheral alpha-1 and alpha-2 adrenergic receptors in three models of hypertension in rats: an in vitro autoradiography study.

In vitro autoradiography was used to compare peripheral alpha-1 and alpha-2 adrenergic receptor binding in various tissues using [3H]prazosin and [3H]rauwolscine, respectively, in three models of experimental hypertension in rats. Models studied included two-kidney, one-clip hypertension, one-kidney, one-clip hypertension, desoxycorticosterone-salt hypertension, and three normotensive control groups: two-kidney control, one-kidney control and salt-loaded control. Blood pressures at death were significantly higher in all three hypertensive groups compared with normotensive controls, but there were no significant differences among the hypertensive or normotensive groups. Plasma norepinephrine levels were significantly elevated in all three hypertensive groups compared with respective controls, with no significant differences among hypertensive or control groups. In all three hypertensive groups, there were significant reductions in binding of aortic and mesenteric vascular alpha-1 receptors, renal tubular alpha-1 and alpha-2 receptors, and adrenal cortical alpha-2 receptors when compared with respective control groups. Reduced binding of cardiac ventricular alpha-1 and alpha-2 receptors was also found in all hypertensive groups, but not to statistically significant levels. No significant differences in intestinal alpha-1 and alpha-2 receptor binding were detected in either hypertensive or normotensive groups. The results suggest increased peripheral sympathetic activity in all three models of experimental hypertension, which is associated with down-regulation of alpha-1 and alpha-2 receptors in a number of peripheral tissues, especially those that control cardiovascular hemodynamics and fluid and salt balance. There is no evidence of an increase in peripheral alpha receptor binding as has often been found in some models of genetic or spontaneous hypertension.

Adrenal Glands↗
PubMed1990

Role of oxygen-derived free radicals in acute angiotensin II--induced hypertensive vascular disease in the rat.

Severe experimental hypertension is associated with vascular hyperpermeability and cellular damage in small arteries and arterioles in rats. Oxygen-derived free radical production is also associated with increased vascular permeability and cellular injury in a variety of conditions, including ischemia-reperfusion and inflammation. To determine if free radicals play a role in the pathogenesis of hypertensive vascular disease, the free radical scavengers superoxide dismutase (SOD), catalase, SOD and catalase, and dimethyl sulfoxide (DMSO) were given to rats made acutely hypertensive with angiotensin II infusions. Untreated hypertensive and normotensive control animals were used for comparison. The effects of scavenger treatment were assessed by in vivo observations of intestinal small arteries by use of stereomicroscopy and videotape and light and transmission electron microscopy to identify and quantitate vascular lesions, and tracer particle injections to determine permeability changes. In vivo observations revealed that scavenger treatment did not alter vascular constriction patterns, vessel caliber, or blood pressures. Electron microscopy of arteries from untreated hypertensive rats showed more severe and more extensive endothelial and smooth muscle lesions, increased tracer particle penetration, and greater fibrin deposition than that found in scavenger-treated hypertensive groups. Quantitation of vascular lesions showed approximately equal reductions in smooth muscle necrosis (p less than 0.01) and fibrin deposition (p less than 0.05) in arteries from each of the scavenger-treated hypertensive groups. The results indicate that the free radical scavengers SOD, catalase, SOD-catalase, and DMSO inhibit (but do not prevent) vascular hyperpermeability and cellular damage during acute, angiotensin II--induced hypertension. These findings suggest that free radicals play a role in the pathogenesis of hypertensive vascular disease, probably by exacerbating the vascular changes initially triggered by an acute elevation in blood pressure.

Acute Disease↗
PubMed1989

Angiotensin II and atrial natriuretic factor-binding sites in various tissues in hypertension: comparative receptor localization and changes in different hypertension models in the rat.

The peptides angiotensin II (ANGII) and atrial natriuretic factor (ANF) regulate blood pressure and salt and water balance by producing antagonistic physiological effects in a variety of tissues. We used in vitro autoradiography with [125I] ANGII and [125I]ANF to compare receptor regulation for both peptides in various tissues in three experimental models of hypertension [two-kidney, one-clip (2K-1C); one-kidney, one-clip (1K-1C); desoxycorticosterone-salt (DOCA-SALT)] and three nonhypertensive control groups [two-kidney (2K-CON); one-kidney (1K-CON); salt-loaded (SALT-CON)]. Blood pressures at death were significantly higher in all three hypertensive groups compared to those in normotensive controls, but there were no significant differences among the hypertensive or normotensive groups, respectively. PRA was highest in the 2K-1C group and lowest in the DOCA-SALT and SALT-CON groups, but plasma ANF levels did not differ significantly among the hypertensive or normotensive groups. In the aorta, ANGII receptor binding was decreased in 2K-1C rats and increased in DOCA-SALT and SALT-CON rats; ANF receptor binding was moderately increased in all three hypertensive groups. Adrenal zona glomerulosa binding for ANGII was highest in the 2K-1C group and lowest in DOCA-SALT rats, while ANF binding was decreased in DOCA-SALT and SALT-CON animals. ANGII renal glomerular binding was increased in DOCA-SALT and SALT-CON groups, and ANF glomerular binding was decreased in the same two groups. In the brain, the subfornical organ showed increased binding for both ANGII and ANF in DOCA-SALT rats. Our results show that tissue receptor binding of ANGII and ANF is regulated in distinct patterns in different models of hypertension, and that these patterns are tissue specific and more complex than simple reciprocal regulation.

Adrenal Glands↗
PubMed1988

Eleven years of experience with the inflatable penile prosthesis.

The 11-year experience with 395 consecutive patients in whom an inflatable prosthesis was implanted for the treatment of chronic erectile impotence is reported. Among these patients the most common etiology was vascular disease, followed by diabetes mellitus and radical pelvic surgery. The original American Medical Systems prosthesis with PPT cylinders shows a 61 per cent complication and revision rate with followup from 3 to 11 years. The newer inflatable prostheses manufactured since 1983 have needed revision in only 13 per cent of the patients followed to 4 years. Salvage procedures and increased product reliability have resulted in 97 per cent of the patients being satisfied. Five types of inflatable prostheses are compared and advantages are discussed.

Adult↗
PubMed1987

Angiotensin-converting enzyme labeled with [3H]captopril. Tissue localizations and changes in different models of hypertension in the rat.

In vitro autoradiography with [3H]captopril was used to localize and quantitate angiotensin-converting enzyme (ACE) in various tissues in two-kidney, one-clip (2K-1C) hypertension, one-kidney, one-clip (1K-1C) hypertension, desoxycorticosterone acetate (DOCA)-salt hypertension, and a normotensive control group. There were no significant differences in mean systolic blood pressure among the hypertensive groups. Plasma renin activity (PRA) was highest in the 2K-1C group (6.20 +/- 2.17 ng/ml per h), intermediate in the 1K-1C group (2.19 +/- 0.62 ng/ml per h) and control group (3.20 +/- 0.53 ng/ml per h), and lowest in the DOCA-salt group (0.07 +/- 0.06 ng/ml per h). In the lungs, aorta, mesenteric arteries, and adrenal medulla, ACE labeling was highest in the 2K-1C group, intermediate in the 1K-1C and control groups, and lowest in the DOCA-salt group. ACE levels in these tissues correlated positively with PRA. In the kidney, anterior pituitary, testis, and choroid plexus of the brain, ACE levels correlated negatively with PRA, with lowest ACE levels in the 2K-1C group and highest levels in the DOCA-salt group. In the epididymis, posterior pituitary, and other regions of the brain, ACE levels did not differ significantly among the groups.

Animals↗