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Biomedical subjects

A J Scott

Publications and source records attributed to A J Scott.

At least 19 recordsLinked to original sources
PubMed1992

A simple method for the analysis of clustered binary data.

A simple method for comparing independent groups of clustered binary data with group-specific covariates is proposed. It is based on the concepts of design effect and effective sample size widely used in sample surveys, and assumes no specific models for the intracluster correlations. It can be implemented using any standard computer program for the analysis of independent binary data after a small amount of preprocessing. The method is applied to a variety of problems involving clustered binary data: testing homogeneity of proportions, estimating dose-response models and testing for trend in proportions, and performing the Mantel-Haenszel chi-squared test for independence in a series of 2 x 2 tables and estimating the common odds ratio and its variance. Illustrative applications of the method are also presented.

Animals↗
PubMed1991

Health proposals and NZMA.

NZMA welcomes the opportunity for public debate over the degree to which the community should fund health care for all. It views the attempts to improve the integration of the health service with interest and hopes to enter a vigorous debate with government to ensure that the detailed proposals yet to be formulated will achieve the purpose we both desire. But the association is disappointed to see policies promoted that are often so reliant upon anecdote and a naive theory of economics. It is disappointing to see health policy altered so radically with so little analysis of facts. Waiting lists, as an example, are analysed with no statement of what proportion of hospital admissions are represented by waiting list patients. Part charges have been introduced in areas where there is no experimental justification for supposing that they will usefully alter patient behaviour. A more sophisticated approach is required. Some change must be sought in the so-called nonnegotiable part of the proposals.

Delivery of Health Care↗
PubMed1991

Breast cancer diagnosis by screening mammography: early results of the Central Sydney Area Health Service Breast X-ray Programme.

The Central Sydney Area Health Service (CSAHS) Breast X-ray Programme is a pilot mammography screening project for breast cancer detection funded by the NSW Government. Screening by two-view mammography is carried out in a mobile van and is offered free to women aged over 45 years living in the CSAHS region, the inner western suburbs of Sydney. In the first 18 months of operation from March 1988, 7193 women were screened: 99 women underwent excision biopsy and 53 cancers were diagnosed. This is an overall detection rate of seven cancers per thousand women screened. Sixty per cent of the cancers were impalpable to the examining surgeon; 19% of all cancers were shown to have axillary node metastasis at the time of diagnosis. These results compare well with those of the major European screening studies.

Aged↗
PubMed1990

Bile duct emptying in response to fat: a validation study.

Fatty meal sonography has been suggested to assess patients with biliary pain after cholecystectomy, but the effects of gallbladder removal on biliary dynamics has not been studied prospectively. Before elective cholecystectomy, 25 patients had their common hepatic ducts' diameter measured by ultrasonography before and after a fat stimulus. In 23, tests were repeated 1 month, 1 year, and 5 years after surgery. In preoperative studies, 5 patients showed dilatation after fat and 2 of these had stones in the common bile duct. However, another 4 patients with stones or sludge in the duct did not show dilatation, so that the response to fat was a poor indicator of patients requiring common bile duct exploration. No patient had major symptoms after surgery. At 1 month and 12 months, the response to fat was variable with more than half of those tested showing no decrease in duct size. A more consistent pattern emerged at 5 years, when 14 of 18 patients tested showed a decrease in common hepatic duct after fat; 3 were unchanged and 1 increased by 1 mm. The response to fat was less consistent and more difficult to measure in the common bile duct, even 5 years after operation. It was concluded that not all patients with indications for exploration of the common bile duct on operative cholangiography show a dilatation response to fat on preoperative testing. Also, fatty meal sonography should be used with caution because the response to fat in asymptomatic patients soon after operation is unpredictable, with occasional patients showing dilation without apparent obstruction. Measurement of common hepatic duct is preferred to common bile duct and increases in diameter of 1 mm are probably not significant.

Bile Duct Diseases↗
PubMed1990

Pre-operative ultrasound measurement of bile duct diameter: basis for selective cholangiography.

In this prospective study, prior to cholecystectomy, the diameter of the common hepatic duct was measured; duct size was then compared with probability of finding stones at operation. Of 115 patients entering the study, 36 had stones removed from the common duct at the time of cholecystectomy but only three (8%) were demonstrated by ultrasonography. No stones were found in ducts less than or equal to 3 mm in size (31% patients). Only two of 26 patients with ducts measuring 4 mm had stones. As duct size increased, so did the probability of stones and all patients with ducts greater than or equal to 9 mm in diameter had stones. It is concluded that pre-operative ultrasound provides a reliable basis for a policy of selective cholangiography.

Cholangiography↗
PubMed1989

Changes in bile duct diameter after cholecystectomy: a 5-year prospective study.

In this prospective study, we have measured with ultrasound the diameter of the common hepatic duct and the common bile duct in a series of 24 patients having elective cholecystectomy. Preoperative measurements by ultrasound were compared with measurements taken directly from operative cholangiograms and excellent correlation was observed (r = 0.938). Studies were repeated 1 mo, 12 mo, and 5 yr after operation. Of 21 patients returning for study at 5 yr, there were 4 patients with 1-mm ducts before surgery who showed an increase in the size of the common hepatic duct but in none was the final measurement greater than 4 mm. Mean common hepatic duct diameter (n = 21) increased from 3.95 mm before to 4.48 mm 5 yr after surgery (p = 0.24, paired t-test). Common bile duct was more easily seen after cholecystectomy and of 13 ducts satisfactorily measured 1 and 5 yr after surgery, 7 showed an increase in size (mean common hepatic duct 1 yr = 4.77 mm, 5 yr = 5.92 mm, p = 0.059, paired t-test). Significant dilatation of the common hepatic duct was seen in only 2 of 21 patients, but a strong trend to minor dilatation was observed in the common bile duct after cholecystectomy.

Cholecystectomy↗
PubMed1979

The Northland Health Scheme.

The Northland Health Scheme, proposed by the Special Advisory Committee on Health Service Organisation (Sachso), is about to become a reality. On 20 February 1978 cabinet approved the setting up of a steering committe in Northland to propose a Health Board structure, establish further working parties to consider local aspects of the scheme, initiate the formation of service development groups, assist SACHSO in developing legislation, and take any other steps that seemed appropriate. The chairman of this committee was named on 1 March and others who have agreed to serve are listed in the New Zealand Medical Journal of 22 March (News, 1978). It is now, therefore, an appropriate moment to scrutinise carefully what is proposed and the principles that underlie the proposals.

Comprehensive Health Care↗
PubMed1979

Dihydrocholesterol-induced gallstones in the rabbit: evidence that bile acids cause gallbladder epithelial injury.

Rabbits fed a diet containing 0.75% dihydrocholesterol for 7 days develop bile acid allodeoxycholic (ADCA) and deoxycholic acid (DCA) stones in the gallbladder. In this model, inflammatory changes in the gallbladder mucosa are often observed even before stones are formed. Within 3 days of the lithogenic diet, abnormalities of platelet function were detectable. Platelet aggregation upon addition of adenosine diphosphate (ADP) was impaired. At the same time the red cells became crenated and developed thorny spicules (echinocytes). This morphological changes was associated with intracellular dehydration and excessive loss of potassium. These changes coincided with a rise in serum ADCA and DCA and preceded a slow rise in serum cholesterol. In vitro incubation studies also suggested that the bile acids had probably caused membrane injury to the platelets and red cells. It is concluded that changes in the bile ADCA and DCA probably induce gallbladder epithelial injury in this model of experimental cholelithiasis.

Animals↗
PubMed1978

Epithelial cell proliferation in diverse models of experimental cholelithiasis.

Proliferation of the epithelial cells of the gall bladder during the initial stages of experimental cholelithiasis has been studied by autoradiography. Rabbits taking a diet with 1% dihydrocholesterol added showed a rise in labelling index from 1.5%-19% by three days. Mice taking a 1% cholesterol 0.5% cholic acid diet showed a similar rise from less than 1% to 15-21% at two and five days. Guinea-pigs receiving lincomycin showed a rise from less than 1% to 6% after 24 hours. These changes, which appear well before the appearance of gall stones, together with previous reports of enhanced mucous secretion during lithogenesis, make it clear that in these laboratory models of cholelithiasis the gall bladder is abnormal well before stones form.

Animals↗
PubMed1977

Benign postoperative jaundice complicating severe trauma.

Five patients are described in whom deep jaundice developed following severe trauma. Only two of the patients showed acute renal failure. All showed the adult respiratory distress syndrome. The livers at autopsy were enlarged and showed centrilobular congestion and cholestases. This syndrome, which is closely analogous, to that described as "benign postoperative jaundice", is more closely associated with the hypoxic hypoxia of acute respiratory failure than with the stagnant hypoxia of acute circulatory failure. It is accentuated by transfusion, and often by disseminated intra-vascular coagulation.

Adolescent↗
PubMed1977

TMJ dysfunction--principles of the clinical examination.

Determining if head pain is related to occlusal disharmony can be a challenge. A brief outline of the clinical examination of these patients was presented. Gross interceptive occlusal contacts should be corrected in all patients. The evaluation of signs and symptoms is the basis for determining whether to "adjust" the asymptomatic patient. Consideration should be given to the intensity of the occlusal disharmony, the level of anxiety, and the patient's adaptive response.

Dental Occlusion, Balanced↗
PubMed1976

Diazoxide-induced renin release in diagnosis of remediable renovascular hypertension.

In hypertensive patients with unilateral renal artery stenosis, intravenous diazoide increased renal vein renin activity more on the involved side than on the contralateral side, whereas, in a group with predominantly unilateral renal parenchymal disease, the increase in renal vein was similar for both kidneys. In patients with bilateral renal artery stenosis, the use of diazoxide was helpful in lateralizing the dominant ischaemic lesion. Diazoide administration appears to be a safe, rapid and convenient method of increasing the sensitivity of the renal vein renin test used in predicting the outcome of surgical treatment of renovascular hypertension. Bilateral renal vein renin determination of established value in the diagnosis of functional renal ischaemia. 1-4 However, in the use of this procedure to predict the efficacy of corrective surgery, false positive and false negative results still occur. Thus, various manoeuvres which stimulate renin release have been employed to improve the sensitivity of the test. 5-7 We report a new application the practical approach to of this procedure in the diagnosis of renal hypertension, which both basal and stimulated levels of renal venous renin activitity can be measured during a brief period of bilateral renal vein catherization.

Adolescent↗