Biomedical subjects
Publications and source records attributed to B Armstrong.
Children with a persistent ductus arteriosus requiring ligation under 6 months of age show evidence of intrauterine growth retardation. By the time of operation the weight centile of 17 (71%) of 24 such infants had fallen, but 20(84%) of the 24 gained weight postoperatively. Those who did not so were either large-for-dates infants growing towards the normal or small-for-dates infants who remained small postoperatively.
The mortality experience of 5971 members of the British Diabetic Association (BDA) was followed-up for between five and eight years to mid-1973. Overall, 1207 deaths occurred compared with 778 expected from the mortality of the population of England and Wales in 1972. This excess of deaths was due almost entirely to diabetes mellitus and ischaemic heart disease. Deaths from cancer (128) were significantly fewer than expected (168), mainly because of a deficit in the number of deaths from cancers related to smoking (cancers of the buccal cavity and pharynx, oesophagus, respiratory system, and bladder). There was also a lower than expected mortality from chronic bronchitis and emphysema. Data on saccharin consumption by BDA members showed that more than half of them used saccharin tablets daily, with an overall daily intake of three to six tablets, depending on age and sex. Information on a small sample of survivors from the mortality study suggested that about 23% of them would have taken saccharin daily for 10 years or more and 10% for 25 years or more by the end of the follow-up. It was concluded that these relatively high levels of saccharin intake had not increased the risk of cancer in general among BDA members.
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Incidence rates for 27 cancers in 23 countries and mortality rates for 14 cancers in 32 countries have been correlated with a wide range of dietary and other variables. Dietary variables were strongly correlated with several types of cancer, particularly meat consumption with cancer of the colon and fat consumption with cancers of the breast and corpus uteri. The data suggest a possible role for dietary factors in modifying the development of cancer at a number of other sites. The usefulness and limitations of the method are discussed.
The frequency with which diabetes mellitus was mentioned on the death certificates of 18,733 patients dying from bladder cancer has been compared with that of 19,709 patients dying from other cancers (excluding cancer of the lung and pancreas). The estimated relative risk of bladder cancer in diabetics was 0-98 with 95% confidence limits 0-70-1-38. There was no increase in risk of bladder cancer in patients with diabetes of long duration. Diabetics were shown by questionnaire to consume substantially more saccharin than non-diabetics, and the duration of regular saccharin use by diabetics was highly correlated with the duration of diabetes. There was therefore no evidence from this study that consumption of above average amounts of saccharin had led to bladder cancer in diabetics. The proporation of current smokers among diabetics was significantly less than among non-diabetics, and this may account for a low relative risk of lung cancer in the former (0-72).
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A modified alkaline lysis method for preparing plasmid DNA from bacterial cells has been developed for automation implementation. The objective of this study was to develop a simplified centrifuge-based protocol that can process samples in a microwell plate. These manual experiments and parametric studies show that the alkaline lysis method can be modified significantly to enable DNA preparations to be done rapidly and reliably by an automated system. The conclusions of this study were (a) centrifugation at < 1500 g is sufficient, (b) centrifugation times need not be extended to compensate for the reduced force, (c) reactions can be done at room temperature, (d) reagent volumes can be reduced over those typically used, and (e) certain reagents can be combined to simplify the handling of fluids.
A system demonstrating the feasibility of high-throughput, centrifugation-based DNA separations and purifications has been constructed and tested. Samples are currently processed at a rate of 96 in approximately 2-3 h. The device implements an automation-optimized alkaline lysis protocol for the rapid extraction of plasmid or cosmid DNA from 1-ml bacteria cultures. The conditions for optimal culturing in deep-well (96 x 1 ml) microwell plates have been developed, and all sample manipulations are done within these plates. The use of microwell plates was essential to obtain high throughput and make manipulations following the DNA preparation (prep) easier because they can then be manipulated using a variety of commercially available robots. The entire prep system is constructed above a Beckman GPR centrifuge and operated under Macintosh IIcx control. This device has systems for fluid handling, microwell-plate manipulations, and centrifuge rotor alignment.
Men who had received compensation for silicosis in Québec between 1938 and 1985 were studied up to the end of 1986 to estimate risk of lung cancer mortality. Particular attention was paid to selection biases inherent in the study of such workers. Age-specific and calendar-year-specific mortality rates of Québec men from 1931 to 1985 were used for comparison. Risk of death from lung cancer in men who had received compensation for silicosis was more than 3 times higher than expected; silicosis may be a strong risk factor for lung cancer mortality.
With growing evidence of the adverse health effects of air pollution--especially fine particulates--investigators must concentrate on the fetus, neonate, and infant as potentially vulnerable groups. Cokeworks are a major source of smoke and sulfur dioxide. In the current study, the authors investigated whether populations residing near cokeworks had a higher risk of adverse perinatal and infant outcomes. Zones of 7.5-km radius around 22 cokeworks in Great Britain were studied, within which the authors assumed that exposure declined from highest levels within 2 km to background levels. Routinely recorded birth and death data for Great Britain during the period 1981-1992 were analyzed. Each individual record had a postcode that referred to a small geographical area of typically 15-17 addresses. The authors calculated expected numbers on the basis of regional rates, stratified by year, sex, and a small-area socioeconomic deprivation score. For all cokeworks combined, the observed/expected ratio (95% confidence intervals within parentheses) within 2 km of cokeworks was 1.00 (0.95, 1.06) for low-birth-weight (i.e., < 2,500 g) infants; 0.94 (0.78, 1.12) for still births; 0.95 (0.83, 1.09) for infant mortality; 0.86 (0.72, 1.03) for neonatal mortality; 1.10 (0.90, 1.33) for postneonatal mortality; 0.79 (0.30, 1.46) for respiratory postneonatal mortality; and 1.07 (0.77, 1.43) for postneonatal Sudden Infant Death Syndrome. Respiratory postneonatal mortality was low throughout the entire 0-7.5-km study area (observed/expected = 0.74 [0.61, 0.88]). There was no statistically significant decline in risk with distance from cokeworks for any of the outcomes studied. The authors concluded that there was no evidence of an increased risk of low birth weight, stillbirths, and/or neonatal mortality near cokeworks, and there was no strong evidence for any association between residence near cokeworks and postneonatal mortality. One must remember, however, the limited statistical power of the study to detect small risks.
A comprehensive questionnaire survey with limited environmental measurements was undertaken in a large sealed office complex where health complaints had been made by employees since the complex was first occupied. Most respondents suffered from upper respiratory tract irritation, eye and skin irritation, and many less specific complaints. Symptoms started shortly after first employment, were troublesome only at work, and persisted at other work locations within the complex. Employees who worked in cubicles tended to complain more than those who worked in open areas or closed offices; however, evidence of less than optimal ventilation, temperature, and humidity correlated poorly with symptom prevalence. The building was designed and ventilated for open-plan use; later partition into offices and cubicles appeared to aggravate the situation. Although concern about pregnancy outcome was expressed by women who conceived while employed at the complex, rates of spontaneous abortion and fetal defect were close to expectation.
1. The association between alcohol consumption and blood pressure was studied in 491 Government employees. The men, aged 21-45 years, volunteered to complete a health questionnaire and submitted to standardized measurements of blood pressure, heart rate and body size. 2. Average weekly alcohol consumption correlated with systolic pressure (R = 0.18, P less than 0.001) but not with diastolic pressure. Systolic pressure increased progressively with increasing alcohol consumption with no obvious threshold effect. An effect of alcohol was seen independent of age, obesity (Quetelet's index) or cigarette smoking. 3. Results indicate that alcohol ranks close to obesity as a preventable cause of essential hypertension in the community.