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Biomedical subjects

M Pitt

Publications and source records attributed to M Pitt.

At least 19 recordsLinked to original sources

Process modelling and simulation for managing clinical care in the community.

'Care in the Community' is an easy catch phrase but a difficult goal. It is a phrase that addresses a current growth area within health care, and one that comes complete with an impressive array of political, economic and social factors that would seem to support the notion of a continuing trend. Technology, specifically information systems, however, has not been successfully cast in a supporting role. There are many reasons for this lack of success but a major one is the mismatch between the understanding of what is required to support the clinical care processes and the specifications of the current systems supplied. Specifically the interest here is in the use and assessment of two computer science techniques, i.e. process modelling and simulation, as suitable means of capturing and communicating requirements so as to bridge the divided and power differential between users and developers of information systems.

Community Health Nursing

The cioAB genes from Pseudomonas aeruginosa code for a novel cyanide-insensitive terminal oxidase related to the cytochrome bd quinol oxidases.

The structural genes for the cyanide-insensitive terminal oxidase (CIO) of Pseudomonas aeruginosa were sequenced. The locus comprised two open reading frames, cioA and cioB, coding for gene products of 488 and 335 amino acid residues with predicted molecular masses of 54241 and 37016 Da respectively. These genes were encoded by a 2.7 kb transcript and probably comprise an operon. Upstream of a major transcriptional start site is a -10 promoter region and, approximately at nucleotides -50 and +13, there are sequences homologous to the binding site of the transcriptional regulator Anr. The deduced amino acid sequences of CioA and CioB are homologous to the cytochrome bd quinol oxidases of Escherichia coli and Azotobacter vinelandii. However, no cytochrome d-like signals were found in wild-type P. aeruginosa strains. An atypical cytochrome d-like signal was seen under low-aeration growth conditions but only in strains in which the cioAB genes were present on a high-copy-number plasmid. The appearance of these cytochrome d-like signals was not paralleled by a concomitant increase in CIO activity. These data support the hypothesis that the CIO of P. aeruginosa does not contain haem d. This raises the possibility that there is a family of bacterial quinol oxidases related to the cytochrome bd of E. coli that can differ in their haem composition from the E. coli paradigm.

Amino Acid Sequence

Transcatheter embolisation of an enlarging acquired coronary arteriovenous fistula in a heart transplant recipient.

A 50 year old, recent cardiac transplant recipient developed systolic and diastolic murmurs but remained asymptomatic. The cause of the murmurs was not evident at transthoracic echocardiography. During routine left heart catheterisation a left anterior descending artery to right ventricular fistula was evident arising from the distal vessel and presumably acquired during routine endomyocardial biopsy. One year later, the patient remained asymptomatic but the calibre of the left anterior descending artery had increased and there appeared to be poor flow in to the proximal branches. The fistula was successfully treated by percutaneous deployment of two detachable embolisation coils in to the distal left anterior descending artery.

Arteriovenous Fistula

Gas gangrene.

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Adenocarcinoma

Screening for glaucoma in a Brisbane general practice--the role of tonometry.

OBJECTIVES: (1) To pilot, and evaluate, a tonometry training intervention for general practitioners; (2) to evaluate the efficacy of three types of tonometer (Perkins, Schiotz and Tonopen) in the hands of these general practitioners; (3) to evaluate the predictive value of tonometry in screening for glaucoma in a general practice population; and (4) to evaluate the acceptability of tonometry to general practice patients. DESIGN: After being trained, three general practitioners recruited 73 of their patients over 50 years of age to attend for measurement of intraocular pressure by tonometry. Intraocular pressure was initially measured by an ophthalmologist using the Goldmann applanation tonometer, and then recorded in random order by GPs using three types of tonometer--the Perkins, Schiotz and Tonopen. SETTING: A group general practice in a middle-class suburb in southern Brisbane. OUTCOME MEASURES: (1) Comparison of measurements on the Perkins, Schiotz and Tonopen tonometers with that of the 'gold standard', the Goldmann Applanation tonometer; (2) prevalence of disc and perimetric abnormality suggestive of glaucoma among those patients with increased intraocular pressure; and (3) the acceptability of contact tonometry to general practice patients. RESULTS: There was considerable variability between intraocular values obtained across doctors and across instruments (6% to 95% of values within 4 mm of the 'gold standard'). The Schiotz tonometer provided the most uniform assessment of intraocular pressure across the groups. Nineteen of the 73 patients (26%) had intraocular pressures > or = 21 mmHg using the 'gold standard'. Of these, 18 were followed up with funduscopy, gonioscopy, repeat measurement of intraocular pressure and visual field assessment. Five had persistent elevations of intraocular pressure > or = 21 mmHg on subsequent assessment, and two had mild abnormalities of cup-disc ratio with normal fields on testing with Humphrey computerised perimetry. CONCLUSION: No one hand-held tonometer proved highly accurate in the hands of all three doctors. Even measured optimally, increased intraocular pressure alone was a poor predictor of glaucoma. Of the population screened, two patients (3%) showed evidence of mild cup-disc abnormality requiring follow-up.

Australia

The SAPPHIRE toolkit: an interactive system for the evaluation of primary healthcare computing.

Since April 1992, the SAPPHIRE Project (Systems Accreditation Project in Primary Healthcare Informatics Requirements and Evaluations) has been funded by the Department of Health in the United Kingdom with the goal of providing a framework for the fair and objective evaluation of General Medical Practice (GMP) computer systems [1]. SAPPHIRE is comprised of three 'facets': A comprehensive specification list for GMP information systems. An Assessment methodology to apply the SAPPHIRE specifications. The Integrated Toolkit. The SAPPHIRE Integrated Toolkit has been developed as an interactive computer-based guide for use in the processes of GMP system procurement and education. By integrating the two other 'facets' of SAPPHIRE, it provides a means of matching a set of user-defined specifications against the systems under consideration. This is achieved by enabling the Toolkit user to interactively weight the presented SAPPHIRE specifications to their individual requirements and then match this weighted specification against a database of benchtest results for available systems. The output from this matching process then gives the range of systems which most clearly meet that particular user's needs as well as highlighting the areas where systems fail to meet their defined requirements. Since the SAPPHIRE specification list is a lengthy document comprised of technical language, the Toolkit uses a range of browsing models to display the specifications in accessible ways to the end-user. These browsing models present the specifications in contexts that are familiar to the everyday experience of healthcare employees and hence are easy to access and understand. In addition, the Toolkit offers a 'Quick Route Questionnaire' which accesses a shortcut to the matching process described above. his presentation will demonstrate the main functions of the Toolkit and outline specific scenarios of use. Another area of discussion will be the approach of the SAPPHIRE Project to the problems and issues of computer system evaluation, with reference to the Toolkit in a communications context, assisting in the transfer of understanding between the technical language of system designers and suppliers and the healthcare professional, who may lack computer expertise [2]. The SAPPHIRE Toolkit has a wide range of applications for facilitating the procurement of, and the education processes entailed in, primary healthcare computing. We view the Toolkit as a potential benefit to many aspects of the healthcare profession, including General Practice, Surgery, Healthcare IT Administration, and Information System Supply and Management.

Ambulatory Care Information Systems

Ankle mortise stability in Weber C fractures: indications for syndesmotic fixation.

A Weber type C ankle fracture was sequentially reproduced in 12 cadaver lower extremities and an external rotation torque was applied at each interval. The fractures were then repaired in staged fashion and the rotational stability of the mortise evaluated. Maximum external rotation of the talus within the mortise averaged 7.7 degrees in the intact ankle and increased by 311% to 31.8 degrees after creation of a Weber C injury. Rigid fixation of the fibular fracture restored 32% of the rotational stability, whereas isolated fixation of the medial malleolus reconstituted 57%. Fibular fixation combined with a syndesmotic screw restored 51% of original stability, and the addition of medial malleolar fixation improved stability to 101%. Bimalleolar fixation without a syndesmotic screw yielded 73% of the original rotational stability. The results of this study suggest that when rigid medial and lateral osteosynthesis can be achieved, syndesmotic fixation may not be necessary.

Ankle Injuries

Bone reinforcement lines in chronic adult osteopenia: a hypothesis.

Although linear bands of increased radiodensity have been described in the tubular bones of children, similar but less often reported structures are frequent in the osteopenic skeleton of middle-aged and elderly patients. In this study, the radiology, pathology, and histology of osseous bands in the mature skeleton were analyzed in 20 cadavers, 29 macerated ancient and modern bone specimens, and 100 recent radiographs. These radiodense areas represent complete or incomplete, horizontally or obliquely oriented bars composed of compact lamellar bone. Although their precise pathogenesis is not clear, they are associated with long-standing (vs. acute) osteopenia. In some instances, bone bars appear to be formed during skeletal growth, remain hidden in the adult because of adjacent trabeculae, and are unmasked by osseous resorption. In other instances, bone bars appear to be formed initially in the mature skeleton as a response to chronic mechanical stress and, as such, are not identical with growth recovery lines observed in children. They are more accurately considered bone reinforcement lines.

Adult

Computed tomography and automated image analysis of prehistoric femora.

Non-invasive characterization of limb bone cross-sectional geometry would be useful for biomechanical analyses of skeletal collections. Computed tomography (CT) is potentially the method of choice. Additionally, CT images are suitable for automated analysis. CT is here shown to be both accurate and precise in the analysis of cross-sectional geometry of prehistoric femora. Beam hardening artifacts can be reduced by using a water bath. As the availability of CT for research increases, both bone density and geometry could be determined simultaneously with this method.

Autoanalysis

Vitamin D metabolites in adolescents and young adults with cystic fibrosis: effects of sun and season.

To assess mineral metabolism in patients with cystic fibrosis and to study the effects of season and sunlight exposure on generation of vitamin D metabolites, we quantified serum levels of calcidiol and calcitriol, other measures of bone metabolism, and radiographic bone mass in 20 adolescents and young adults with CF and 20 age-matched normal volunteers. Levels of calcidiol were lower in patients with CF than in controls and lower in Massachusetts than in Arizona in both study groups. Controls in Arizona had higher (P less than 0.05) levels of calcitriol than in Massachusetts throughout the year. All control subjects in both states had higher levels of calcitriol than did patients with CF. Patients in Massachusetts had significantly lower levels of calcitriol in winter than in summer. Summer levels of calcitriol in CF were significantly higher in Massachusetts than in Arizona; during winter, lower levels were found in Massachusetts than in Arizona. Mean bone density in patients with CF was 88% and 89% of normal American standards in Massachusetts and Arizona, respectively. These data indicate a seasonal, sunlight-related influence on levels of vitamin D metabolites in patients with CF receiving approximately 1000 IU vitamin D per day. Older patients with CF with progressively diminishing sunlight exposure may be at increased risk for development of osteopenia. The detected radiographic abnormalities of bone mineralization may also be related to malabsorptive deficiencies of calcium and phosphorus.

25-Hydroxyvitamin D 2

Osteopenic bone disease.

Osteoporosis, osteomalacia, and hyperparathyroidism are the common causes of skeletal osteopenia. Radiograms of the skeleton are a basic part of the clinical evaluation of these osteopenic processes. Accurate interpretation of these radiograms is difficult; the presence and degree of osteopenia is often a subjective estimate. This article discusses radiographic features of the common deossifying disorders, including objective criteria that may be useful in routine clinical practice.

Adult

Spinal cord injury, spinal fracture, and spinal stenosis in ankylosing spondylitis.

The authors report a retrospective review of 105 patients with ankylosing spondylitis (AS) diagnosed over a 6-year period in Tucson, Arizona. In the series, there were 13 patients with spinal fractures and eight with severe spinal cord injury. Two patients with central cord contusion had no demonstrable cervical spine fracture. Injury was often trivial and dislocation at fractures sites was minimal, demonstrating the extreme fragility of these patients. Spinal stenosis, which has not previously been associated with AS, was documented in three cases. Pseudarthrosis, a destructive vertebral lesion that does not require surgical decompression or fusion, was found in four patients; this entity is believed to originate as a pathological or traumatic fracture. Atlanto-axial subluxation and basilar invagination associated with spinal ankylosis occurred in one patient. The study emphasizes the value of computerized tomography scanning of the spine for diagnosis, and halo-vest application as a nonoperative treatment for cervical immobilization. Early diagnosis and appropriate therapy to decompress, reduce, and immobilize unstable spinal lesions may result in reduction of the 29% mortality rate and 45% permanent neurological morbidity rate observed after spinal fracture in this series of AS patients. Because of the high operative complication rate observed, nonsurgical immobilization is the recommended treatment unless spinal dislocation or bone fragment displacement has occurred at the fracture site.

Adult

Hyperaldosteronism, hyperparathyroidism, medullary sponge kidneys, and hypertension.

Hyperparathyroidism and hyperaldosteronism coexisted in association with medullary sponge kidneys in a 27-year-old woman with severe hypertension. A modest fall in systolic and diastolic pressure followed removal of a parathyroid adenoma. Blood pressure was controlled with spironolactone therapy and restored to normal after removal of an aldosterone-secreting adrenal tumor. Elevated levels of aldosterone may have been responsible for the severe hypertension, while hypercalcemia may have had a synergistic effect on the arteriolar response to circulating vasoactive peptides.

Adenoma