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Biomedical subjects

G D Webster

Publications and source records attributed to G D Webster.

At least 55 records · Page 3Linked to original sources
PubMed1992

The development of a technique to estimate the number of motor units in the urethral sphincter.

An electromyographic technique is presented that has been developed in an effort to quantitate the number of motor units in the urinary sphincter. Sphincter contraction was provoked by electrical stimulation and recorded with a catheter mounted electrode. Incremental stimulation produced corresponding increments of sphincter contraction that were recorded as the magnitude of the sphincter electromyogram. Estimates of the number of motor units in the sphincter were made by analysis of variance of a Poisson distribution. Using this method, the mean number of motor units in the sphincter of five dogs was estimated to be 129 with values ranging from 80 to 182. Anatomical correlation was sought by infiltrating this sphincter with horseradish peroxidase, which is taken up by axonal transport to stain the motor neurons in the spinal cord. The mean number of motor neurons was 229 with values ranging from 116 to 358. There are technical and physiologic explanations for the observed differences between the predicted and the actual number of motor neurons stained and this is addressed in the discussion.

Animals↗
PubMed1992

Evaluation of augmentation cystoplasty for severe neuropathic bladder using the hostility score.

In a retrospective study, the pre-operative urodynamic findings of 41 myelodysplastic patients who had undergone enterocystoplasty for intractable incontinence or deteriorating upper urinary-tracts were compared with findings from similar studies. An objective score combining five urodynamic parameters, the Hostility Score, was calculated before and after surgery to assess its clinical applicability in guiding and monitoring patient management. A score of greater than or equal to 5 should be avoided, if possible, as deleterious upper urinary-tract changes can occur even while on conservative management. In this series the mean pre-operative Hostility Score was 5.6, with 26 patients having a mean score of greater than or equal to 5. After surgery the mean score was reduced to 2.8, with no patient having a score of greater than 4. We conclude that the Hostility Score is a reliable tool for the management and follow-up of patients who have neurogenic bladder disease as a result of myelodysplasia.

Adolescent↗
PubMed1991

Transvaginal needle suspension procedures for recurrent stress incontinence.

The results of transvaginal needle suspension in 36 patients with stress urinary incontinence who failed previous operation were reviewed. Eighteen patients underwent a Stamey endoscopic needle suspension, and a Peyrera-Raz cystourethropexy was performed on the remainder. Recurrent stress incontinence was confirmed by history, physical examination, and urodynamic studies. Cure rates of 78 percent for the Stamey procedure and 83 percent for the Raz operation were achieved. Excluding patients with voiding dysfunction or urge incontinence postoperatively due to bladder instability, the failure rates were 6 percent and 11 percent, respectively. Analysis of the results according to the preoperative maximal urethral pressures demonstrated that low-pressure urethras if accompanied with urethrovesical hypermobility have no impact on the results if the anatomic abnormality was corrected adequately by the needle suspension. Thus, the transvaginal needle suspension was found to be highly effective in patients with low-pressure urethras, who failed previous operation, but had persistent bladder neck hypermobility, and suggests that this method of surgical repair should be the first choice in this selected group.

Female↗
PubMed1991

Inflatable penile prosthesis: effect of device modification on functional longevity.

The Scott inflatable penile prosthesis has undergone a continual evolution since its introduction in 1973. A review of 266 patients at Duke University Medical Center who received primary implantation of AMS inflatable penile prostheses from 1979 to 1988 revealed the modifications in the prosthesis have increased the functional longevity and hence the reliability of this surgical treatment for erectile impotence.

Erectile Dysfunction↗
PubMed1991

An objective score to predict upper tract deterioration in myelodysplasia.

Bladder dysfunction in myelodysplasia may present a significant hazard to the upper tract and a threat to kidney function. Urodynamic features of high leak pressure and detrusor-sphincter dyssynergia have been associated with an increased risk. We have developed an objective score to describe urodynamic findings in myelodysplasia. The score includes consideration of bladder compliance, detrusor contractility and reflux, in addition to leak pressure and sphincter behavior. In 171 myelodysplastic patients a significant correlation was demonstrated between the score and upper tract studies at the time of urodynamics and the score and the management decision. Of 73 myelodysplasia patients with normal upper tracts at the first urodynamics study hydronephrosis later developed in 14. The score was a potent predictor of outcome (p = 0.0006).

Child, Preschool↗
PubMed1991

Repair of pelvic fracture posterior urethral defects using an elaborated perineal approach: experience with 74 cases.

A total of 74 patients with posterior urethral distraction defects (1.5 to 7 cm. long) that followed pelvic fracture was managed by a 1-stage perineal repair. End-to-end anastomosis was performed in all cases but in 66 a variety of surgical maneuvers were necessary to accomplish a tension-free anastomosis. These techniques, which included distal urethral mobilization, corporeal body separation, inferior pubectomy and supracrural urethral rerouting, were resorted to in a sequential manner as needed. Excellent results were achieved in 96% of the cases. These surgical techniques are described and discussed.

Adolescent↗
PubMed1991

Evaluation and management of incontinence after implantation of the artificial urinary sphincter.

Despite the fact that the AS-800 artificial urinary sphincter represents a significant advance in the treatment of urinary incontinence, for many reasons, incontinence persists or recurs in a small percentage of cases. This is often a challenging problem to manage; however, a logical and sequential approach (as outlined in the algorithm in Figure 2) will aid in successful diagnosis and treatment.

Cystoscopy↗
PubMed1990

Accessory phallic urethra in adult female.

Duplication of the urethra with an accessory phallic urethra in females is a rare anomaly usually discovered early in life because of associated genitourinary anomalies. We report on a thirty-three-year-old female with this anomaly who presented with double urinary stream and recurrent urinary tract infections. The nature of this anomaly, its diagnosis, and management are reviewed.

Adult↗
PubMed1990

The outcome of transvaginal cystourethropexy in patients with anatomical stress urinary incontinence and outlet weakness.

Preoperative urodynamic and radiographic evaluation identified features of bladder neck and urethral weakness in 62 women undergoing cystourethropexy for the correction of anatomical stress urinary incontinence. Despite the coexistence of anatomical and outlet factors persistent stress incontinence due to intrinsic urethral weakness occurred in only 2 patients (3%), neither of whom was identifiable by preoperative urethral function evaluation. Preoperative coexisting urgency symptoms had no impact on the surgical outcome, resolving in the majority of patients with sensory urgency and responding to alternate postoperative management in those with bladder instability. We conclude that anatomical correction by cystourethropexy is appropriate for women with mixed etiology incontinence in whom urethrovesical hypermobility is present.

Adult↗
PubMed1990

Voiding dysfunction following cystourethropexy: its evaluation and management.

We report on 15 women who underwent cystourethropexy for anatomical stress incontinence and who subsequently had dysfunctional voiding symptoms. All 15 women underwent retropubic takedown of the prior repair and substitution with an obturator shelf repair. All 13 women who had symptoms of bladder instability experienced resolution of these symptoms. Of 7 patients who were in urinary retention and required clean intermittent catheterization only 1 continued to require clean intermittent catheterization to facilitate bladder emptying after obturator shelf substitution. In this series a successful outcome was achieved in 14 of 15 patients (93%).

Female↗
PubMed1990

Salvage posterior urethroplasty after failed initial repair of pelvic fracture membranous urethral defects.

Experience with 20 salvage urethroplasties in patients with pelvic fracture membranous urethral defects who failed previous delayed urethroplasty is presented. A total of 15 patients was successfully managed by 1-stage procedures, 14 by bulboprostatic reanastomosis and 1 by a tubed pedicled island of skin. Substitution urethroplasty with a staged perineoscrotal skin tube inlay was performed in 5 patients in whom an anastomosis could not be achieved either due to an excessively long urethral defect or inelasticity of the anterior urethra precluding its elongation for an anastomosis free of tension. A successful result was achieved in 19 of the 20 patients (95%). The rationale for procedure selection is discussed.

Adult↗
PubMed1990

Crystal structure and sequence-dependent conformation of the A.G mispaired oligonucleotide d(CGCAAGCTGGCG).

The crystal structure of the dodecanucleotide d(CGCAAGCTGGCG) has been determined to a resolution of 2.5 A and refined to an R factor of 19.3% for 1710 reflections. The sequence crystallizes as a B-type double helix, with two G(anti).A(syn) base pairs. These are stabilized by three-center hydrogen bonds to pyrimidines that induce perturbations in base-pair geometry. The central AGCT region of the helix has a wide (greater than 6 A) minor groove.

Adenine↗
PubMed1990

Training and practice activities of hematology and medical oncology diplomates.

Diplomates of the American Board of Internal Medicine in hematology or medical oncology were surveyed about the content and setting of their practices, adequacy of training for professional activities, and preferences for certification. The response rate was 60% (N = 2516). Approximately 20% of cases seen by diplomates in hematology involve nonhematopoietic neoplasms, and 10% of cases managed by oncologists concern hematologic disorders. Diplomates were satisfied with training in areas corresponding to their own field(s) of certification, except for immune and/or acquired immunodeficiency syndrome-related and nonneoplastic leukocyte disorders. Training deficits most frequently recalled were office management skills and psychosocial/communication skills. Nearly half of the respondents preferred to maintain separate certificates. Data indicate that the two fields are distinct. However, the overlap in practice brings into question the adequacy of training for diplomates who manage problems outside of their field of certification and suggests that some degree of cross-fertilization in all training would be beneficial.

Certification↗