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Biomedical subjects

G D Webster

Publications and source records attributed to G D Webster.

At least 73 records · Page 4Linked to original sources
PubMed1990

The non-covalent interaction of pyrrolo[2, 1-c] [1, 4]benzodiazepine-5, 11-diones with DNA.

A series of 15 pyrrolo[2, 1-c] [1, 4]benzodiazepine-5, 11-diones has been synthesized and evaluated for in vitro DNA binding by thermal denaturation and fluorescence quenching studies with calf thymus (CT) DNA. The results indicate that two compounds of the series, 7 and 8, elevate the melting point of DNA by 2.9 +/- 0.6 and 3.3 +/- 0.8 K, respectively. Similarly, a significant quenching of the fluorescence of the dihydroxy analogue 8 was observed upon interaction with CT-DNA. As controls, the dihydroxy isomer 9 with the reverse stereochemistry at C2 and the non-substituted parent dilactam 12, failed to increase the DNA melting point or exhibit significant quenching upon interaction with DNA. In addition, preliminary experiments with GC- and AT-rich polymers suggest some sequence-dependent properties for dilactams 7 and 8. Overall, these results indicate a highly specific structural requirement for DNA binding. Molecular modelling with d(GTAGATC), d(GCAGATC) and d(GCGTAGC) duplex sequences has provided a model based on hydrogen bonding between the dihydroxy dilactam 8 and DNA, that rationalizes some of the results obtained. It is possible that the observed interactions represent the non-covalent (binding) component of the interaction of covalently-bonding anthramycin-type anti-tumour antibiotics with DNA.

Anthramycin↗
PubMed1989

The management of chronic interstitial cystitis by substitution cystoplasty.

A total of 19 patients with interstitial cystitis symptoms intractable to conservative management underwent supratrigonal excision of the symptomatic bladder. Reconstruction to produce a low pressure reservoir was accomplished with a segment of remodeled intestine anastomosed to the bladder remnant. Patients were selected because of a history of typical intractable severe symptoms in the presence of characteristic endoscopic features. Of the patients 12 were cured of the pain and frequency, 4 experienced improvement, and 3 failed to improve and underwent urinary diversion. Preoperative features did not predict the outcome, although poor results occurred more often in those with large preoperative bladder capacities while under anesthesia and those who had postoperative voiding problems requiring self-catheterization.

Adult↗
PubMed1989

Perineal repair of membranous urethral stricture.

Membranous urethral disruption secondary to pelvic fracture often results in an obliterative stricture. Most of these lesions can be repaired by a one-stage procedure provided certain maneuvers are accomplished to facilitate approximation of the bulbar to the prostatic urethra: urethral mobilization as far proximal as the suspensory ligament of the penis, separation of the corporal bodies, excision of a wedge of the inferior surface of the pubis exposed by corporal body separation, and on occasion, routing of the mobilized urethra around the corporal body. With these methods, even lengthy defects can be bridged to create a tension-free anastomosis.

Anastomosis, Surgical↗
PubMed1988

A criterion-referenced examination in cardiovascular disease.

This study described criterion-referenced tests of electrocardiograph reading skill and basic knowledge in cardiology, assessed their dependability and validity, and explored their impact on overall certification rates. Data indicated that the standard-setting processes and the two criterion-referenced tests produced dependable results both separately and together. Scores of each had the expected relationships with quality of residency training and experience with the examination. Moreover, these sections of the examination identified a small subset of examinees who failed the criterion-referenced sections but passed the norm-referenced examinations. Taken as a whole these results replicate the findings of an earlier study in terms of a criterion-referenced test of electrocardiograph reading skill and extended them to a criterion-referenced test of basic knowledge in cardiology.

Cardiology↗
PubMed1988

Artificial urinary sphincters: plain radiography of malfunction and complications.

Inflatable artificial urinary sphincters provide excellent voluntary continence. Eighty-four consecutive patients underwent implantation of artificial urinary sphincters for intractable urinary incontinence; 33 patients had 58 episodes of sphincter malfunction, and eight patients had eight complications involving a functional prosthetic sphincter. Retrospective analysis was performed to determine the value of plain radiography of the pelvis in patients with sphincter malfunction or complication. The cause of malfunction in the majority of patients was a system leak and subsequent loss of hydraulic fluid (31 occurrences; 53%). Plain radiography permitted correct identification of all instances of fluid leakage in patients with opacified prostheses. Plain radiographs were of no value in examining patients with nonopacified prostheses or the complications of cuff erosion or wound infection. Due to the low cost and noninvasive nature of plain radiography of the pelvis, we conclude that it should be used as the initial diagnostic modality in patients with previously opacified but currently dysfunctional artificial urinary sphincters.

Female↗
PubMed1988

The effect of changes in medical knowledge on examination performance at the time of recertification.

The purpose of this paper was to determine if the decline in performance with time since completion of training on the 1980 ABIM Recertification Examination can be explained by a difference in performance on items testing different types of knowledge. Results showed that candidates further out of training performed less well on items testing new or changing knowledge, while performance on items testing stable knowledge was relatively constant across age groups.

Certification↗
PubMed1987

Experiences with bladder reconstruction in children.

The results in 56 children (28 with neurogenic bladder dysfunction) undergoing enterocystoplasty between 1981 and 1985 are presented. Ileal, ileocecal, right colon and sigmoid segments were used in tubular and opened configurations. Our experience leads us to recommend opened ileal segment reconstruction in neurogenic bladder patients and those with weak anal sphincters generally, and open ileocecal or open right colon segments in patients with other etiologies. Continence was achieved in 53 patients, although secondary procedures, particularly at the bladder outlet, were required in 13. When ureteral reimplantation was required we achieved excellent success with normal-sized or mildly dilated ureters regardless of the operative technique used. Initial failures to prevent reflux in the face of marked ureterectasis using the ileocecal valve have been resolved by a modified technique of intussusception and fixation. An over-all favorable experience is reported, which we believe permits us to formulate certain rules that will improve the acceptability and success of bladder reconstruction in general.

Adolescent↗
PubMed1987

Cystometric properties of ileum and right colon after bladder augmentation, substitution or replacement.

Cystometric studies were performed on 38 patients who had undergone augmentation, substitution or replacement enterocystoplasty. These studies were done to determine the choice of bowel segment to augment or replace the detrusor and the shape in which the bowel segment should be reconstructed. Eleven patients underwent tubular and 10 detubularized right colon cystoplasty, while 10 underwent tubular (Camey bladder) and 7 detubularized ileocystoplasty. Compliance curves were normal in nearly all patients except those who underwent tubular ileocystoplasty. Cystoplasty contractions were more common with tubular cystoplasty. These contractions appeared at a lower bladder capacity and were higher in amplitude in tubular cystoplasty patients. Detubularizing the bowel for bladder reconstruction appears to create a better low pressure capacitor with better compliance and fewer high pressure cystoplasty contractions.

Adolescent↗
PubMed1987

A standardized examination in the interpretation of electrocardiograms.

A standardized objective examination was developed by the Cardiovascular Subspecialty Board of the American Board of Internal Medicine to assess competence in the interpretation of electrocardiograms (ECGs). The questions consisted of 12 lead ECGs with lead II and V1 rhythm strips, accompanied by brief clinical statements. Examinees chose their answers from a comprehensive list of 129 choices; the list was the same for each question. The score from the ECG examination was combined with scores from the other sections of the examination to derive a single score for the Cardiovascular Board examination using a norm-referenced method for determining the passing score. An additional trial was conducted to study the feasibility of testing for a minimal level of competence; the trial used a subset of "core" ECGs and a criterion-referenced scoring method based on a consensus of members of the Cardiovascular Board on the level of performance that should be expected of certified cardiologists. Fifty examinees (2.7%) failed the core ECG examination. If examinees had been required to pass both the core ECG examination and the remainder of the examination, 164 examinees (9%) would have changed their pass-fail status on the overall examination. The examination appeared to be a valid test for a minimal level of skill in this area of cardiology. The minimal level of competence was met by a large majority but not all of the examinees.

Cardiology↗
PubMed1987

Ratings of residents' clinical competence and performance on certification examination.

The American Board of Internal Medicine (ABIM) requires directors of internal medicine residency programs to rate their residents in overall clinical competence and its essential components. In the study reported here, the authors investigated the relationships among these ratings and compared them with the residents' performance on the ABIM's certification examination in the years 1980 through 1985. The ratings of the individual components of clinical competence were correlated moderately with examination performance and very highly with each other. The individual components that were less dependent on medical knowledge (for example, interpersonal skills or humanism) had slightly smaller correlations with examination performance. The ratings of overall clinical competence were also related moderately to examination performance. Changes in the pattern of the ratings over time indicated that fewer candidates were receiving lower ratings while more were receiving higher ratings. The pass rates for each rating level were the same or lower; for example, the pass rate for candidates rated 5 was 68 percent in 1980 and 56 percent in 1985. The similar ranking of examinees by the program directors and the examination provides evidence for the validity of the examination.

Certification↗
PubMed1987

Performance of a dangerous answer subtest within a subspecialty certifying examination.

Previous studies have been reported suggesting that a population of candidates for specialty board certification can be identified who pass the certification examination but who give an unduly high number of 'dangerous' responses, indicating their acceptance of actively harmful actions. To confirm these results, a retrospective analysis was undertaken of a Subspecialty Board of Nephrology certification examination. Experts identified a subtest of 75 dangerous answers. The performance of candidates on this subtest was compared with their performance on the total examination. The subtest was moderately reliable, ranked criterion groups appropriately, had a correlation with the total test of 0.71, and using the standard used for the total examination, identified the certification status of 84% of candidates. However, when the correlation was corrected for unreliability, the correlation became 1.0, indicating that a dangerous answer subtest, at least in this examination and population, does not identify a unique population of certified but 'dangerous' doctors.

Certification↗
PubMed1987

Augmentation and replacement cystoplasty: sonographic findings.

Sonographic evaluation of the urinary tract after bladder augmentation and replacement procedures often reveals unexpected findings that result from incorporation of bowel into the urinary bladder wall. Familiarity with such findings is important to avoid misinterpreting them as abnormalities. The authors reviewed the sonograms of 47 patients. The most common findings were thick or irregularly shaped bladder walls (96%), pseudomasses within the bladder lumen (89%), and fine debris or linear strands (47%). Pseudomasses were potentially the most confusing; they are usually attributable to normal bowel folds, intraluminal mucus collections, or segments of bowel that have been intussuscepted into the bladder to prevent reflux.

Adolescent↗
PubMed1987

Surgical treatment of interstitial cystitis. Indications, techniques, and results.

Conservative treatment should be satisfactory for 90 per cent of patients with interstitial cystitis. When severe symptoms are refractory and constitute a major disability, surgical treatment should be considered. Usually symptoms will have been present for at least three years before operative methods are used. If bladder capacity (general anesthetic) is greater than 400 ml, and the major symptom is bladder pain, denervation by cystolysis may be considered. If bladder capacity (general anesthetic) is less than 400 ml, supratrigonal cystectomy and substitution colocystoplasty is the treatment of choice.

Colon↗
PubMed1986

Predictors of the performance of foreign medical graduates on the 1982 certifying examination in internal medicine.

This study describes a cohort of foreign medical school graduates (FMGs) who first sat for the American Board of Internal Medicine's (ABIM) 1982 certifying examination, compares their performance with that of US medical school graduates, describes differences between US citizen FMGs and alien FMGs, and examines which background factors predict success on the ABIM examination. Data for this study were derived by combining information retained by the Educational Commission for Foreign Medical Graduates with ABIM data. Most FMGs who took the 1982 ABIM certifying examination for the first time were educated in and citizens of Asia, but a sizable minority were US citizens educated in Europe. Scores and program directors' ratings were lower for FMGs than US medical school graduates, and they attended different types of training programs. United States citizen FMGs were very similar to alien FMGs. Foreign medical school graduates who did well on the ABIM examination had done well on the Educational Commission for Foreign Medical Graduates examination and were rated highly by their residency program director.

Achievement↗