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W L Smith

Publications and source records attributed to W L Smith.

At least 127 records · Page 7Linked to original sources
PubMed1995

The long-term effectiveness of a radiology memorandum.

RATIONALE AND OBJECTIVES: This informal prospective study was designed to document the long-term effectiveness of a radiology department policy memorandum as a communication tool. A memorandum outlining the departmental policy regarding radiographic imaging of pregnant or possibly pregnant patients served as the study model. METHODS: A departmental obstetric policy memorandum was distributed to all radiology personnel, including faculty and residents. The effectiveness of the memorandum was measured by the ability of all department personnel to answer specific test questions about the policy 1 year after its distribution. RESULTS: Nine (41%) in the faculty/fellow group and seven (41%) residents gave partially correct answers about policy content. There were no totally correct policy content answers in either group. Thirty-eight (64%) of the technology staff knew the entire policy content. CONCLUSION: Staff radiologists, fellows, and residents demonstrated an unacceptable level of knowledge concerning the policy content and location. Technologists, technology students, and clerks demonstrated a more acceptable level of knowledge of the policy than did radiologists. A single memorandum without repetition or constant surveillance is not an effective communication tool to alert radiologists to the importance of understanding and implementing policy directives.

Clinical Competence↗
PubMed1995

Influence of prior radiologic information on the interpretation of radiographic examinations.

RATIONALE AND OBJECTIVES: We examined whether and how the provision of previous radiologic information (previous films and reports) influences the interpretation of radiographs. METHODS: We prospectively studied 35 radiologists' interpretation of 311 plain-film radiology cases in a clinical setting. A radiologist first interpreted the current radiograph with only the information given on the consultation request. Subsequently, the same radiologist received, in random order, either the previous radiographs or the previous written reports, reviewed the diagnosis, changing it when necessary, noted the recognition of new findings, and adjusted his or her degree of confidence. A third interpretation used whichever type of information was not supplied for the second. All three readings of a study were performed at the same sitting by the same radiologist. A diagnosis and degree of confidence were recorded for each reading. RESULTS: The additional information, either radiograph or written report, significantly increased the confidence of the radiologist at each stage of interpretation. The largest increase in confidence occurred whenever previous films were introduced. In group A (second reading, reports; third reading, old films), new observations were made in 17.3% of cases on the second reading and in 19.9% on the third reading. In this group, diagnoses were changed in 14% on the second reading and in 9% on the third reading. In group B (second reading, old films; third reading, old reports), new observations were made in 16.9% of cases on the second reading and 7.3% on the third reading. Diagnoses were changed in 11% on the second reading and in an additional 5% on the third reading. Most changes were toward a more specific diagnosis. CONCLUSION: Prior information significantly increased the radiologists' confidence, facilitated new observations, and allowed more specific diagnoses. Prior radiographs were more valuable than reports in some respects.

Confidence Intervals↗
PubMed1995

Current status of residency programs: survey of program directors.

RATIONALE AND OBJECTIVES: This survey was compiled to provide current data on the structure and content of radiology residency programs and the role of the residency program director. METHODS: A survey, created in electronic form and on paper, was distributed to all United States academic, private, and military radiology residency program directors. RESULTS: Of the 202 survey forms distributed, 168 (83%) were completed and returned. Eighty percent of respondents support national curriculum guidelines, but most do not favor national curriculum requirements. About half (53%) of programs spend 6 months in "view box" nuclear medicine; others provide some experience by lectures and on-call time. Most programs (60%) relieve residents of some call during the senior year. Some programs (28%) allow seniors time away from clinical duties to study for the oral board exam, and 17% permit time away to study for the written boards. Seventy-eight percent of programs have had a "problem resident," and 47% have asked a resident to leave the program. Directors' most frequently expressed concern was threat of diminished residency numbers due to decreased funding.

Attitude of Health Personnel↗
PubMed1995

Being a radiologist.

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Attitude of Health Personnel↗
PubMed1995

Legal system.

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Civil Rights↗
PubMed1995

Specificity of expression and effects of eicosanoid mediators in normal physiology and human diseases.

The eicosanoids are a family of oxygenated arachidonic acid derivatives that potently mediate diverse physiological and pathophysiological processes. Recent research on eicosanoids has revealed novel pathways of synthesis, a family of related cell membrane receptors, and distinctive roles in cellular functions. There are two cyclooxygenases that convert arachidonic acid to thromboxane and prostaglandins, one of which is localized in the endoplasmic reticulum and the other in the nuclear envelope. The cyclooxygenases differ in their susceptibility to inhibition by nonsteroidal antiinflammatory drugs. The leukotriene-generating pathway consists of a cytosolic perinuclear 5-lipoxygenase, two integral nuclear envelope proteins, termed 5-lipoxygenase-activating protein and LTC4 synthase, and a cytosolic LTA4 hydrolase. Each protein of the leukotriene synthetic pathway is a target for specific pharmacological intervention. Cellular recognition and effects of eicosanoids are mediated by at least 12 different G protein-associated primary receptors, which differ in tissue distribution, signaling mechanisms, and cellular behavior, as well as binding specificity. Transient localized increases in tissue concentrations of eicosanoids and the concurrent upregulation of complementary receptors influence differentiation, migration, and specific activities of cells in immunity and other integrated physiological responses.

Eicosanoids↗
PubMed1995

Case study: obsessive-compulsive disorder after severe traumatic brain injury in an adolescent.

The neurological underpinnings of obsessive-compulsive disorder (OCD) are still largely undetermined. We report a prospective case study of a young subject who developed OCD and impulsive aggression after traumatic brain injury. The implications are that frontal and temporal lobe lesions may be sufficient to precipitate OCD in the absence of clear striatal injury and that compulsivity and impulsivity may represent different psychophysiological states.

Brain↗
PubMed1995

Pharmacological characterization of RS 25259-197, a novel and selective 5-HT3 receptor antagonist, in vivo.

1. The pharmacological effects in vivo, of RS 25259-197, a selective 5-HT3 receptor antagonist, have been investigated. 2. In anaesthetized rats, RS 25259-197, administered by the intravenous, intraduodenal or transdermal route, dose-dependently inhibited the von Bezold-Jarisch reflex induced by 2-methyl 5-HT (ID50 = 0.04 micrograms kg-1, i.v., 3.2 micrograms kg-1, i.d. and 32.8 micrograms per chamber, respectively). In this regard, when administered intraduodenally, RS 25259-197 was more potent and exhibited a longer duration of action than either ondansetron or granisetron. 3. In conscious ferrets, RS 25259-197, administered intravenously or orally, dose-dependently inhibited emesis induced by cisplatin. The ID50 estimates of RS 25259-197 were 1.1 micrograms kg-1, i.v. and 3.2 micrograms kg-1, p.o. In this respect, RS 25259-197 was more potent than ondansetron and equipotent with granisetron. 4. In conscious dogs, RS 25259-197, administered intravenously or orally, dose-dependently inhibited emesis induced by cisplatin (ID50 = 1.9 micrograms kg-1, i.v. and 8.5 micrograms kg-1, p.o.), dacarbazine (ID50 = 4.1 micrograms kg-1, i.v. and 9.7 micrograms kg-1, p.o.), actinomycin D (ID50 = 4.9 micrograms kg-1, i.v. and 2.5 micrograms kg-1, p.o.) and mechlorethamine (ID50 = 4.4 micrograms kg-1, i.v. and 3.0 micrograms kg-1, p.o.). Against each of the emetogenic agents, RS 25259-197 was very much more potent than ondansetron. When tested at equi-effective intravenous doses against cisplatin-induced emesis in dogs, RS 25259-197 had a longer duration of anti-emetic activity (7 h) than ondansetron (4 h). At doses up to and including 1000 microg kg-1, p.o., neither RS25259-197 nor ondansetron was capable of inhibiting apomorphine-induced emesis.5. At doses up to 1000 microg kg-1, i.v., RS 25259-197 produced no meaningful haemodynamic changes in anaesthetized dogs.6. In summary, RS 25259-197 is a novel, highly potent and orally active 5-HT3 receptor antagonist in vivo. With respect to its anti-emetic activity, RS 25259-197 appears to be a significant improvement over ondansetron in terms of potency and duration of action.

Administration, Oral↗
PubMed1995

Added value of radiologist consultation to family practitioners in the outpatient setting.

PURPOSE: To measure the added value of a radiologist's consultation to the interpretation of radiographs previously read by a family practitioner. MATERIALS AND METHODS: The authors reviewed 1,674 chest and extremity radiographs previously read by a family practitioner and consulting radiologist. The 196 radiographs in which there was a discrepancy between the family practitioner's and radiologist's report were evaluated by a radiologist and family physician not involved in and blinded to the original interpretations. The overall accuracy of the participants was determined and differences statistically quantified. RESULTS: The overall sensitivity of the radiologists was greater than that of the family practitioners (92% vs 86%); specificity was not significantly different. For extremity examinations, there were no significant differences in accuracy of the radiologists and family practitioners; the sensitivity of radiologists for chest studies was considerably greater (89% vs 80%). Radiologic consultation was of particular value in the detection of pneumonia and masses. CONCLUSION: At a family practice center, the radiologist's role for extremity radiographs might be limited to individual consultation, with review of all chest radiographs.

Ambulatory Care↗
PubMed1995

Expression cloning of an AVP-activated, calcium-mobilizing receptor from rabbit kidney medulla.

Arginine vasopressin (AVP) is a nonapeptide that regulates body fluid and blood pressure homeostasis. We have used expression cloning in the Xenopus laevis oocyte system to identify cDNA clones from a rabbit renal medullary expression library encoding an AVP receptor linked to Ca2+ mobilization. cRNA generated from positive clones conferred upon oocytes the capacity to mobilize intracellular Ca2+ in response to AVP. A cDNA clone encoding a protein of 780 amino acids was isolated, sequenced, and subcloned into an SV40-based expression vector. Expression of the cloned protein [designated the vasopressin-activated, calcium-mobilizing (VACM-1) protein] in COS-1 cells, resulted in increased 125I-labeled AVP binding [dissociation constant (Kd) of approximately 2 nM] and increased AVP-induced mobilization of Ca2+. Importantly, 125I-AVP could be immunoprecipitated both from detergent-solubilized membranes from COS-1 cells expressing VACM-1 protein and from an in vitro translation system, in which VACM-1 protein was synthesized, using antibodies prepared against a synthetic peptide derived from the NH2-terminal sequence of VACM-1. Interestingly, immunohistochemical staining of rabbit kidney sections with this antibody showed specific staining of collecting tubule epithelia. The deduced amino acid sequence is not homologous with any nucleic acid or amino acid sequences reported to date, including those of the V1 and V2 AVP receptors. The VACM-1 protein may represent a novel AVP receptor.

Amino Acid Sequence↗
PubMed1995

Teleradiology for rural hospitals: analysis of a field study.

We compared the accuracy of a low-cost teleradiology system with plain film at a small rural hospital. The comparison was a case-control, paired-comparison study. In total 377 consecutive cases were read prospectively by teleradiology and later by independent interpretation of the plain films. 'Truth' was determined in discrepant cases by further investigation of available records and images. Sensitivity and specificity were determined for each modality, and agreement using the kappa statistic. There was 90% agreement between teleradiology and plain film, with no significant differences. Sensitivities (0.88, 0.89) and specificities (0.98, 0.98) of the two methods were almost identical. McNemar's test indicated no significant differences in the accuracy of the two modalities. We conclude that inexpensive teleradiology for small rural hospitals is equivalent to plain film for radiologists' interpretation.

Case-Control Studies↗
PubMed1995

Radiologic interpretation by family physicians in an office practice setting.

BACKGROUND: Radiology is an integral part of the office practice of many family physicians. Nevertheless, data are sparse on the performance of family physicians in this endeavor. This study investigated the performance of family physicians at interpreting radiographs ordered in a free-standing family practice office. METHODS: A consecutive series of radiographic studies performed at a family practice office during a 3-year period was surveyed. All radiographic studies included in this analysis (N = 1674) were separately interpreted by the family physician ordering the study and an overreading radiologist. If the interpretations agreed, the studies were accepted as having been correctly interpreted. Cases in which the interpretations disagreed were reexamined. RESULTS: Family physicians correctly interpreted 92.4% of the radiographic studies (95% confidence interval, 91.0 to 93.6). Their accuracy with extremity films (96.0%) was significantly higher than their accuracy with chest films (89.3%, P < .001). Family physicians were more likely to correctly interpret normal films (95.2%) than abnormal ones (85.9%, P < .001). Thirty-five percent of the cases in which there were differences between family physician and radiologist interpretations were correctly interpreted by family physicians. CONCLUSIONS: Family physicians showed a high degree of accuracy in radiologic interpretation in an office setting. Chest films were inherently more difficult to interpret than extremity films. Because correct interpretation depends on body part examined and the prevalence of disease, the performance of family physicians will probably vary in different practice settings.

Ambulatory Care↗
PubMed1995

Biochemistry of prostaglandin endoperoxide H synthase-1 and synthase-2 and their differential susceptibility to nonsteroidal anti-inflammatory drugs.

The principal pharmacological effects of nonsteroidal anti-inflammatory drugs (NSAIDs) are due to their ability to inhibit prostaglandin synthesis. NSAIDs block the cyclooxygenase activities of the closely related PGH synthase-1 and PGH synthase-2 (PGHS-1 and PGHS-2) isozymes. NSAIDs are therapeutically useful due to their analgesic, anti-pyretic, anti-inflammatory, and anti-thrombogenic properties. Major side-effects of NSAIDs include their ulcerogenic and nephrotoxic activities. All clinically approved NSAIDs in general use today inhibit both PGHS-1 and PGHS-2. Recently, inhibitors have been identified that are selective toward PGHS-2 and that have potent analgesic and anti-inflammatory activities with minimal ulcerogenic activity. If the new PGHS-2 selective NSAIDs can effectively inhibit inflammatory prostaglandin synthesis by PGHS-2, without inhibiting PGHS-1 prostaglandin synthesis required to regulate sodium and water resorption, and renal blood flow, it is likely that these new drugs will also have significantly less renal toxicity than present-day NSAIDs. In this article, the mechanisms of actions of NSAIDs primarily at the biochemical level, including the reactions catalyzed by PGHSs, will be discussed. In addition, the biochemical properties of these isozymes, and the differential regulation of the PGHS-1 and PGHS-2 genes, will be examined.

Amino Acid Sequence↗
PubMed1995

Tracheomalacia before and after aortosternopexy: dynamic and quantitative assessment by electron-beam computed tomography with clinical correlation.

To correlate the dynamics of tracheal collapse with clinical upper airway obstruction before and after aortosternopexy, seven boys and three girls (mean age, 10 months) underwent dynamic evaluation of the trachea by electron-beam computed tomography (EBCT). The site, extent, and severity of collapse were correlated with symptomatology and details of operative procedure. When > 50 % area collapse was used as the criterion for tracheomalacia, segmental involvement occurred above the aortic arch in all patients, extending to the aortic arch level in only four. Tracheomalacia involved two or fewer 8-mm levels in seven patients and more than two levels in three. Eight patients underwent one aortosternopexy procedure, resulting in clinical improvement in six and correlating well with EBCT findings. Of the remaining two patients who had single aortosternopexy and did not show clinical and radiographic improvement, one required operative repair of a vascular ring and the other continued to have recurrent respiratory tract infections. On the basis of EBCT findings, two patients required additional innominate arteriopexies: one improved, and the other remained symptomatic, requiring tracheostomy. EBCT is a noninvasive modality that allows preoperative diagnosis of tracheomalacia. More importantly, the operative decision and technique are guided by an objective and quantitative assessment of tracheal collapse.

Aorta, Thoracic↗