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Biomedical subjects

A J Scott

Publications and source records attributed to A J Scott.

At least 37 records · Page 2Linked to original sources
PubMed1993

Albuminuria in people at least 40 years old: effect of alcohol consumption, regular exercise, and cigarette smoking.

We investigated the relation between albuminuria and life-style factors in 5670 people, ages 40 years and over, who participated in a health screening survey of a local workforce. The degree of albuminuria showed piecewise log-linear relationships with alcohol consumption and cigarette smoking, with changes in slope (and 95% confidence interval) corresponding with 5 (2, 8) g of alcohol/day and 10 (6, 14) cigarettes/day. After adjusting for age, gender, ethnicity, and other life-style variables, relative risks (95% confidence interval) of slight albuminuria for people consuming > 32 g of alcohol/day compared with nondrinkers, and for cigarette smokers compared with nonsmokers, were 1.74 (1.02, 2.98) and 1.37 (1.01, 1.88), respectively. However, there was no significant effect of exercise. We conclude that slight albuminuria is significantly associated with cigarette smoking and heavy alcohol consumption, consistent with its role as an index of risk of cardiovascular disease.

Adult↗
PubMed1993

Dietary nutrient intakes and slight albuminuria in people at least 40 years old.

We studied the relation between diet and slight albuminuria in 5416 people, ages 40 years and over, who participated in a health screening survey of a local workforce. Degree of albuminuria showed log-linear univariate relations with dietary protein, cholesterol, and sodium intakes, and negative log-linear univariate relations with dietary fiber and polyunsaturated to saturated fat (P/S) ratio. After adjusting for age, gender, and ethnicity, the relative risk (95% confidence interval) for slight albuminuria was significantly increased in people reporting dietary cholesterol consumption > 226 mg/day compared with people reporting consumption < or = 226 mg/day [1.32 (1.02, 1.70)], and significantly reduced in people reporting dietary fiber consumption > 26 g/day compared with people reporting consumption < or = 26 g/day [0.74 (0.58, 0.95)]. There was no significant effect of dietary protein, P/S ratio, or salt intake. We conclude that risk of slight albuminuria is increased by consumption of dietary cholesterol and reduced by consumption of dietary fiber.

Adult↗
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↗
PubMed1988

Comparison of mandelate dehydrogenases from various strains of Acinetobacter calcoaceticus: similarity of natural and 'evolved' forms.

In previous work it had been shown that Acinetobacter calcoaceticus wild-type strain NCIB 8250 had only an L-mandelate deydrogenase but it could give rise to mutants that contained an evolved D-mandelate dehydrogenase; conversely, wild-type strain EBF 65/65 had only a D-mandelate dehydrogenase but gave rise to mutants that possessed an evolved L-mandelate dehydrogenase. Several other wild-type strains of A. calcoaceticus have now been shown to grow on both enantiomers of mandelate. In every case the L-mandelate dehydrogenases were found to be much more heat-stable and insensitive to inhibition by p-chloromercuribenzoate than were the D-mandelate dehydrogenases when measured in bacterial extracts. All the D-mandelate dehydrogenases in the wild-type strains were inactivated to about the same extent by an antiserum that had been raised in a rabbit against an evolved D-mandelate dehydrogenase. An evolved D-mandelate deydrogenase (from a mutant strain derived from strain NCIB 8250) and an original D-mandelate dehydrogenase (from a mutant strain derived from strain EBF 65/65) were purified to homogeneity by the same procedure and were indistinguishable as judged by immunological cross-reactivity of the native and the sodium-dodecyl-sulphate-denatured enzymes, solubility in cholate, net charge at pH 7.5, pI value, salting-out properties, Mr value, apparent K(m) value for D-mandelate, heat-stability and sensitivity to p-chloromercuribenzoate. The most likely explanation for the appearance of evolved mandelate dehydrogenases in strains of A. calcoaceticus is that cryptic genes become expressed.

Acinetobacter↗
PubMed1987

Purification and properties of L-mandelate dehydrogenase and comparison with other membrane-bound dehydrogenases from Acinetobacter calcoaceticus.

L-Mandelate dehydrogenase was purified from Acinetobacter calcoaceticus by Triton X-100 extraction from a 'wall + membrane' fraction, ion-exchange chromatography on DEAE-Sephacel, (NH4)2SO4 fractionation and gel filtration followed by further ion-exchange chromatography. The purified enzyme was partially characterized with respect to its subunit Mr (44,000), pH optimum (7.5), pI value (4.2), substrate specificity and susceptibility to various potential inhibitors including thiol-blocking reagents. FMN was identified as the non-covalently bound cofactor. The properties of L-mandelate dehydrogenase are compared with those of D-mandelate dehydrogenase, D-lactate dehydrogenase and L-lactate dehydrogenase from A. calcoaceticus.

Acinetobacter↗
PubMed1982

The evolution of morphologic changes in the gallbladder before stone formation in mice fed a cholesterol-cholic acid diet.

Mice were fed a lithogenic diet containing 1% cholesterol and 0.5% cholic acid, and the sequence of morphologic changes in the gallbladder was followed. Histologic changes were studied with light microscopy and cell proliferation with autoradiography. Mucus glycoprotein production was studied with a spectrum of glycoprotein histochemical stains and electron-microscopic morphometry of membrane-bound mucus secretory granules. There was a rapid and early increase in cell proliferation of the epithelial cells and an increase in mucus production, which took place long before any observable cholesterol crystal precipitation. The gallbladder epithelial cells showed early focal pseudostratification and large numbers of degenerative cells. These changes culminated in glandular metaplasia and the formation of Rokitansky-Aschoff sinuses later in the gallstone induction phase. These observations clearly indicated that gallbladder epithelial injury had taken place before gallstone formation. The authors hypothesize that the consequences of these cellular changes play a contributory role in causing gallstone formation.

Animals↗
PubMed1980

Further observations in lincomycin-induced cholelithiasis in guinea-pigs.

Further experiments are reported on Lincomycin-induced cholelithiasis in guinea-pigs. The biochemical events in the bile and blood, and the chemical composition of gallstones, have been studied. The gallstones resemble human pigment stones in chemical composition. The clear hepatic bile and the normality of the bile salt--phospholipid--cholesterol equilibrium, the rise in beta-glucuronidase and hexosamine levels with the gallbladder, have reaffirmed that epithelial injury is most probably the primary lithogenic factor. Ligation of the cystic duct and the construction of a common hepatic duct-duodenum bypass did not prevent the development of acute cholecystitis, suggesting the lithogenic factor was mediated through the blood circulation and not through the enterohepatic circulation of bile.

Animals↗
PubMed1980

Estimating ventilation/perfusion distributions from inert gas data: a Bayesian approach.

In recent years, experimental techniques using inert gas studies have been developed for determining essentially continuous distributions of the ventilation/perfusion ratio over a lung. Mathematically, the technique requires the recovery of 'smooth' solutions of grossly underdetermined systems of linear equations. This paper investigates the use of Bayesian smoothing techniques and shows that, provided the true underlying distribution of ventilation/perfusion ratios is relatively smooth and well-behaved, it is possible to recover reliable estimates of such distributions.

Bayes Theorem↗
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↗