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Biomedical subjects

A J Wilson

Publications and source records attributed to A J Wilson.

At least 109 records · Page 6Linked to original sources

Telematics and protocols of care in critical care environments.

The paper discusses the potential roles for protocols of care within critical care environments from the perspective of providing real-time support for their application. The discussion is based around a conceptual model of care in critical care environments. This model has been developed in the wider context of developing information technology systems to support clinical care in critical care environments. The conceptual model of care is a three layer model which demonstrates both the hierarchical and temporal aspects of the care delivered to patients. It is proposed that if the value of protocols of care is to be realised in critical care environments then they must be seamlessly integrated into the routine data management associated with the care of patients. In order to demonstrate this and to evaluate the utility of this concept in the clinical environment, the systems from the AIM TANIT (Telematics in Anaesthesia and Intensive Therapy) project have been used as prototype platforms. The application of the concepts developed are described in two critical care environments: the anaesthesia department and the intensive care unit. Problems in using protocols of care in intensive care units suggest that integrating these with a problem solving methodology to create an integrated care plan may be a more appropriate approach to patient management.

Anesthesia Department, Hospital↗

Comparison of the sensitivity of the caudal fold skin test and a commercial gamma-interferon assay for diagnosis of bovine tuberculosis.

A study to determine and compare the sensitivity of the caudal fold tuberculin test (CFT) and a commercial gamma-interferon (gamma-IFN) assay for diagnosis of bovine tuberculosis was conducted. A dairy herd with approximately a third of the cattle infected with Mycobacterium bovis was chosen for this study. All cattle from this herd were slaughtered, and tissue specimens for bacteriologic culturing and histologic examination were collected. Results of the CFT and gamma-IFN assay were compared with results of bacteriologic culturing and histologic examination to determine test sensitivity. Results were analyzed, using each of the following 4 standards to classify cattle as infected: positive test result by bacteriologic culturing only; histologic examination only; bacteriologic culturing and histologic examination; and bacteriologic culturing or histologic examination. Sensitivity of the CFT ranged from 80.4 to 84.4%, depending on the standard of comparison. Sensitivity of the gamma-IFN assay ranged from 55.4 to 97.1%, depending on the standard of comparison and on the method of interpretation. The CFT was significantly (P < 0.001) more sensitive than the gamma-IFN assay for diagnosis of bovine tuberculosis when the gamma-IFN assay was conducted and interpreted as instructed by the manufacturer. Maximum overall sensitivity was achieved when results of the CFT and gamma-IFN assay were interpreted in parallel.

Animals↗

Expression of inducible nitric oxide in human lung epithelial cells.

Nitric oxide (NO) is increased in the exhaled air of subjects with several airway disorders. To determine if cytokines could stimulate epithelial cells accounting for the increased NO, the capacity of the proinflammatory cytokines (cytomix: tumor necrosis factor-alpha, interleukin-1 beta, and interferon-gamma) to increase inducible nitric oxide synthase (iNOS) was investigated in A549 and primary cultures of human bronchial epithelial cells. Cytomix induced a time-dependent increase in nitrite levels in culture supernatant fluids (p < 0.05). Increased numbers of cells stained for iNOS and increased iNOS mRNA was detected in the cytokine-stimulated cells compared to control (p < 0.05). Dexamethasone diminished the cytokine-induced increase in nitrite, iNOS by immunocytochemistry, and iNOS mRNA. These data demonstrate that cytokines, such as those released by mononuclear cells, can induce lung epithelial iNOS expression and NO release, and that this is attenuated by dexamethasone.

Amino Acid Oxidoreductases↗

Rabies policy.

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Animals↗

Inducible nitric oxide synthase is increased in murine lung epithelial cells by cytokine stimulation.

Nitric oxide (NO) is detectable in exhaled air. To elucidate whether airway epithelial cells could be a source of NO, we investigated the expression of inducible nitric oxide synthase (iNOS) by the murine lung epithelial cell line, LA-4, in response to cytokine stimulation and the ability of corticosteroids to modulate this effect. Stimulation with cytomix, a combination of interleukin-1 beta, tumor necrosis factor-alpha, and interferon-gamma, elevated nitrite levels by 873% in the culture supernatants and enhanced the conversion of arginine to citrulline by 273% at 24 h. An increased number of cells stained for iNOS and an increase in iNOS mRNA was also observed. Dexamethasone decreased the cytokine-induced increase in nitrite levels, NOS activity, iNOS immunoreactivity, and mRNA but did not change the half life of iNOS mRNA. These results show that lung epithelial cells can release NO, a process which can be inhibited by dexamethasone.

Amino Acid Oxidoreductases↗

Information management systems for intensive care.

On-going work relating to the development of advanced information management systems for intensive care is described. The objective of this paper is to outline the complex issues that need to be addressed when developing such systems. This work is in part sponsored by the Commission of the European Communities under the AIM TANIT project, and an overview of its approach is given. Data protection, security and confidentiality aspects are emphasised, together with the need to balance data availability with the need for security.

Computer Security↗

Results of the 1993 survey of the American Association of Academic Chief Residents in Radiology.

RATIONALE AND OBJECTIVES: A survey of chief residents of academic radiology programs is conducted annually on behalf of the American Association of Academic Chief Residents in Radiology (A3CR2). Data are obtained to improve the training of diagnostic radiology residents and to increase the understanding of radiologists and their associates about issues of interest to radiologists in training. METHODS: Questionnaires were mailed to 133 accredited programs in the United States and Canada. A wide variety of demographic and common interest questions were asked. The analysis took into account geographic location of the responders and the size of the residency program. Comparisons were made to the data from prior years. RESULTS: Completed surveys from 93 programs (70%) were returned. The percentage of women residents is increasing. Important regional and size variations exist in several areas including salary, workload, prior clinical training, resident/fellow ratios, post residency plans, and call schedules. Although many chief residents feel knowledgeable about the health care system, opinions about the future of radiology and medical care are tentative. CONCLUSIONS: This survey provides important demographic information about academic radiology residency programs. The summary information regarding plans for fellowship training, resident call schedules, and opinions about socioeconomic issues may be useful for chief residents, program directors, and departmental chairmen.

Canada↗

Diagnosis of focal bone lesions using neural networks.

RATIONALE AND OBJECTIVES: Use of a neural network to diagnose focal lesions of bone was evaluated. METHODS: Imaging features of 709 lesions were encoded into a predetermined database. Data were divided into four groups and were analyzed using cross-validation by a two-layer feed-forward neural network. RESULTS: The lesions comprised 43 different pathologic diagnoses. Overall, the network was 85% accurate in distinguishing benign from malignant lesions. With a differential list of five diagnoses, the list was internally consistent regarding benign and malignant lesions 81.9% of the time. The network correctly diagnosed 56% of the lesions by pathologic diagnosis as its first choice. It included the correct diagnosis 71.8% of the time in a differential list of three diagnoses and 87.3% of the time in a differential list of nine diagnoses. CONCLUSION: Although not yet adequate for clinical use, neural network diagnosis of bone lesions is in its infancy and has important implications for the future analysis of focal bone lesions.

Bone Neoplasms↗

Comparison of spiral computed tomography versus conventional computed tomography multiplanar reconstructions of a fracture displacement phantom.

PURPOSE: The capabilities of spiral computed tomography (CT) versus conventional CT to represent minimal fracture displacements on multiplanar reconstruction images in a phantom model were evaluated. MATERIALS AND METHODS: A displacement phantom was created from Teflon and was scanned with conventional and spiral CT, at slice collimations of 2 mm, 3 mm, and 5 mm. Three Z-axis interpolation algorithms (360_LI, 180_LI and 180_HI) were employed to process the spiral image data into planar images. Displacements of 5 mm or less were represented in the phantom, and the resultant multiplanar reconstructions were analyzed for the precision of displacement representation. Specifically, the edge profiles of the reconstructed images were measured and compared. RESULTS: Spiral CT reconstruction edge profiles were similar to those of conventional CT when minimal table increments (3 mm/sec or less), and an advanced interpolation algorithm (180_LI) was employed. Images obtained with 360_LI interpolation manifested the effect of widened slice profile even when employing minimal table speeds. CONCLUSIONS: With minimal table increment (3 mm/sec or less) and a high-order interpolation algorithm (180_LI), spiral-CT-derived reconstructions demonstrate similar edge profile resolution to reconstructions obtained from conventional CT.

Algorithms↗

Computer-based videotape analysis of trauma resuscitations for quality assurance and clinical research.

PURPOSE: To automate time (and motion) studies of major trauma resuscitations. TECHNIQUES: We modified an existing time-motion study technique based on time-encoded videotaping for medical imaging workstation human factors analysis. Videotapes were recorded of the trauma room during normal clinical activity using an unobtrusive mounted camera. The videotapes are displayed through a customized interface using a Macintosh-based display system. Within this platform, the time-motion study module allows flexible task definition, multiple concordant task assignment, and various summary result presentations. We established an expert panel of two traumatologists, two emergency radiologists, and two time-motion study experts. The expert panel prospectively and uniquely defined important recognizable procedural and cognitive tasks and personnel (MD, RN, EMT, RT, etc.) involved in trauma resuscitation based on pilot recordings and collective experience. These task functions were used to define a menu in the time-motion analysis software. During retrospective videotape review, the beginning and ending times of each task performed were recorded by electronically highlighting each defined individual and task. The summary results can be displayed in list, tabular, or graphic form by individuals, personnel classifications, or tasks.

Clinical Protocols↗

Evaluation of the injured cervical spine: comparison of conventional and storage phosphor radiography with a hybrid cassette.

PURPOSE: To compare conventional and storage phosphor radiography of the injured cervical spine. MATERIALS AND METHODS: Sixty-five patients underwent imaging in a supine position while wearing a cervical collar. Matched storage phosphor and conventional lateral cervical spine radiographs were obtained with an 18 x 24-cm hybrid cassette. Edge-enhanced and nonenhanced copies of each computed radiograph were printed on film, and the images were sent via a computer network to a remote imaging workstation. Four radiologists read the conventional radiographs, the two hard-copy computed radiographs, and the soft-copy images and used a binary scale to score the visibility of bone and soft-tissue structures. RESULTS: All readers scored better in all areas with computed radiographs, and a statistically significant (P = .030) improvement in performance was seen for soft-tissue structures. CONCLUSION: Storage phosphor imaging offers advantages over conventional radiography, and digital images may be a viable alternative to film.

Cervical Vertebrae↗

PGD2 is an intermediate in agonist-stimulated nitric oxide release in rabbit skin microcirculation.

We investigated the role of endogenous prostaglandins and NO in the blood flow response of skin microcirculation in vivo. Test agents were injected intradermally in anesthetized rabbits and changes in skin blood flow measured with a laser-Doppler flow probe. Skin blood flow increased 75% at 7.33, 6.77, 11.63, 10.30, 10.55, 8.20, and < 7 -log mol/site with acetylcholine, ATP, bradykinin, prostaglandin D2 (PGD2), prostaglandin E2 (PGE2), NO gas in solution, and nitroprusside respectively. Co-injection of indomethacin (3 x 10(-9) mol/site) or NG-nitro-L-arginine methyl ester (L-NAME; 10(-7) mol/site) with either acetylcholine or bradykinin abolished the effects. This suggests a link between NO and prostaglandin release. Arachidonic acid increased blood flow, which was inhibited by indomethacin, L-NAME, or the PGD2-receptor antagonist BW-A868C. Blood flow responses to either intradermal acetyl-choline or bradykinin, but not to NO in solution, were abolished by co-injection with BW-A868C. PGD2-mediated vasodilation was abolished by L-NAME or BW-A868C, but not by indomethacin. There was no evidence of a link between NO and prostaglandin release in precontracted rabbit aortic rings in vitro. The results suggest that, in the microcirculation of rabbit skin, acetylcholine- and bradykinin-mediated vasodilation involve the arachidonic acid-PGD2-NO pathway.

Acetylcholine↗

Endemic fluorosis of the skeleton: radiographic features in 127 patients.

OBJECTIVE: A wide range of radiographic appearances have been reported in skeletal fluorosis, but little has been written about the spectrum of radiographic features. We evaluated the spectrum of radiographic appearances in this disorder to help with its diagnosis and differentiation from other metabolic skeletal disorders. MATERIALS AND METHODS: One hundred twenty-seven patients with clinically proved endemic fluorosis had radiographs of the chest, spine, pelvis, elbow, forearm, and knee obtained. The radiographic findings were classified as osteosclerosis, osteopenia, intermittent growth lines, diaphyseal widening, or soft-tissue ossification. Two different osteopenic patterns were defined: an osteoporotic pattern with overall decreased bone density and an osteomalacic pattern that combines the features of osteoporosis with bone deformity. Soft-tissue ossification included involvement of ligaments, tendons, and interosseous membranes. RESULTS: Ninety-eight of the patients (89% of the adults) had some evidence of calcification and/or ossification of the attachments of ligaments, tendons, muscles, and interosseous membranes. Osteosclerosis was seen in 54 patients (43%), and osteopenia was seen in 51 patients (40%). Of the patients with osteopenia, the osteoporotic pattern was seen in 28 and the osteomalacic pattern in 23. Growth lines were found in 89 patients (70%). Metaphyseal osteomalacic zones were found in children. Diaphyseal widening was present in 35 patients (28%). CONCLUSION: Endemic skeletal fluorosis can have a wide variety of radiographic appearances, including calcification and/or ossification of the attachments of soft-tissue structures to bone, osteosclerosis, osteopenia, growth lines, and metaphyseal osteomalacic zones.

Adolescent↗

Fractures of the tibial plateau: value of spiral CT coronal plane reconstructions for detecting displacement in vitro.

OBJECTIVE: The purpose of this in vitro study was to determine the value of spiral CT for detecting displacement of fractures of the tibial plateau. The exact amount of inferior plateau depression, if any, is a primary criterion for deciding between surgical management and conservative management. MATERIALS AND METHODS: An artificial fracture was produced in a cadaveric tibial plateau. Inferior displacements of 0, 1, 3, and 5 mm were created at the fracture. Spiral CT scans of each displacement were obtained with table speeds of 2, 3, and 5 mm/sec. Section collimation equaled table increment. Coronal image reconstructions were produced by use of standard scanner software. The images were interpreted by six musculoskeletal radiologists. RESULTS: Interpretation accuracy was greatest with coronal images created from the 2 mm/sec scans. For distinguishing 5-mm fracture displacements, the average diagnostic sensitivity and specificity were 96% and 93%, respectively; when a 2-mm depression was used as the criterion for clinical significance, the sensitivity was 100% and the specificity was 69%. CONCLUSION: When minimal table increment and collimation are used, spiral CT can detect clinically important inferior depressions of tibial plateau fractures. On the basis of the results of this study, when spiral CT is used for tibial plateau fracture assessment, we recommend 2-mm section collimation, 2-mm table speed, and reconstruction of images at 1-mm increments.

Algorithms↗