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Biomedical subjects

N Pearce

Publications and source records attributed to N Pearce.

At least 217 records · Page 12Linked to original sources
PubMed1986

Time-related factors as potential confounders and effect modifiers in studies based on an occupational cohort.

Time-related factors which are potential confounders and effect modifiers in studies based on an occupational cohort are reviewed. The most frequently considered ones include age at first exposure, duration of exposure, interval from exposure to disease recognition, and age at risk. These factors are related to the "healthy worker effect," which appears to be more pronounced among workers with the longest durations of employment and older ages, at date of hire, but weaker with longer length of follow-up and older age at risk. Hence, use of an internal comparison group may not eliminate bias since confounding will occur if the exposed and unexposed groups differ in their distributions across these factors. It is also shown, using the multistage model of carcinogenesis, that these factors may be important effect modifiers. Fortunately, generally straightforward methods of control exist both for stratified analyses and for the commonly used mathematical modeling approaches. Although no firm recommendations can be made, it would appear to be important to control for length of follow-up in the design or analysis of most studies based on an occupational cohort, and controlling for age at first exposure may also be desirable under many circumstances.

Adult↗
PubMed1985

Incidence of hepatocellular carcinoma in New Zealand, 1974-78: ethnic, sex and geographical differences.

The incidence of hepatocellular carcinoma in New Zealand is examined for the period 1974-78. There was a significant north-south gradient for both Maori and non-Maori incidence rates, with the rates in the northern half of the North Island being approximately double those in the South Island. Within each region, Maori rates were approximately three times those of non-Maoris and incidence rates of males were approximately three times those of females. Incidence was particularly high in the Bay of Plenty, Waiapu and Otago hospital board districts. These patterns are generally consistent with available information concerning the distribution of hepatitis B surface antigen (HBsAg) carriage in New Zealand and suggest that HBsAg carriage is likely to be a major risk factor for hepatocellular carcinoma in New Zealand, as it is in other countries.

Carcinoma, Hepatocellular↗
PubMed1985

Asthma mortality.

Explore the source record for details and available documents.

Adolescent↗
PubMed1985

Research in fire prevention.

This paper describes in broad terms, the fire testing programme we carried out on whole bed assemblies in 1984. It should be clear that the tests were carried out in a thoroughly rigorous scientific manner. As always there is more to be done. The immediate task of finding the so called 'safe' bed assembly is proceeding with the search this year for safer pillows. Softer barrier foams are now being produced and it may be that the NHS could use full depth foam mattresses rather than a barrier foam wrap. On the engineering side I have explained the false alarm problem, and I have reviewed some of the research we are doing to see that new technology is used to give us better systems in future. Life safety sprinkler systems give the possibility of truly active fire protection in patient areas. They will enhance fire safety but at the moment no trade-offs can be offered in other areas of fire protection--either active or passive. My final point is that although I have considered the Department's fire research by looking separately at specific projects, the fire safety of a hospital must always be considered as a total package. To be effective, individual components of fire safety must not be considered in isolation but as part of the overall fire safety system.

Beds↗
PubMed1982

Computer predictions of New Zealand doctor numbers.

Considerable debate has been generated about "the coming crisis in medical manpower" with most current analyses predicting a large surplus of doctors in the late 1980s. However, predictions can be complex because of potential fluctuations in the input variables due to political and social factors. Variables affecting active doctor numbers include the numbers of medical students graduating each year, immigration, emigration, the proportions of males and females, age at retirement, and extent of part-time work. A computer simulation is described which enables the relative effects of these variables to be compared. It is found that adjustments in the medical school intake have a relatively small short-term effect compared with the effects of adjustments in several of the other variables, particularly immigration numbers.

Computers↗
PubMedDate not supplied

Monoclonal antibodies for intravesical radioimmunotherapy of human bladder cancer.

Local administration of radioimmunoconjugates may allow successful tumor therapy. Bladder cancer appears well suited to this approach, because of its superficial and multifocal nature, and because it will allow direct intravesical administration of conjugates. Implantation of human bladder cancer cell lines in the bladder wall of nude rats results in tumor formation, providing an excellent model to test this. We have developed two murine monoclonal antibodies (MAbs), BLCA-8, IgG3, and BLCA-38, IgG1, both of which react with malignant cells and shed into voided urine of patients with transitional cell carcinoma (TCC) of the bladder, but not with normal bladder urothelial cells. Radioimmunoconjugates produced with 131Iodine (131I) or 125I have been used for biodistribution studies following administration directly into the bladder. Radioiodinated intact MAbs or Fabs administered intravesically into nontumor-bearing rats did not leak into the systemic circulation and were stable in urine for up to 100 h. Biodistribution studies carried out following intraperitoneal or intravesical administration of radioimmunoconjugates to tumor-bearing nude rats indicate good tumor uptake of both MAbs. Together with immunoreactivity assays, these studies demonstrate that 131I-labeled MAbs have considerable potential for intravesical radioimmunotherapy of human bladder tumors, and further studies are under way.

Administration, Intravesical↗
PubMedDate not supplied

Congenital defects and miscarriages among New Zealand 2, 4, 5-T sprayers.

A survey was conducted of professional New Zealand 2, 4, 5-T sprayers and a comparison group of agricultural contractors with a total of 989 respondents. The numbers of births, congenital defects, and miscarriages were identified from 1969 to 1980 by a postal questionnaire. Each pregnancy outcome was classified according to whether or not the father sprayed 2,4,5-T during the year of the pregnancy outcome, or the previous year. The relative risk estimates of 1.19 for congenital defects, and 0.89 for miscarriages, were not statistically significant. These results are reassuring as far as male professional 2,4,5-T sprayers are concerned. In addition, the extent of exposure of their wives from helping with spray activities, and from washing contaminated clothes, has not had a detectable reproductive effect.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMedDate not supplied

Latency analysis in occupational epidemiology.

Allowance for prolonged disease induction and latency times is an important consideration in occupational epidemiology studies of cancer and other delayed effects of exposure. Two useful approaches for assessing prolonged induction and latency periods are (1) exposure lagging and (2) considering exposures only within moving time windows. The exposure weighting scheme proposed by Jahr2 to assess exposure burdens is another method that accounts for induction and latency, although not explicitly. These three approaches, which are shown to be special cases of exposure weighting, are illustrated with an analysis of lung cancer mortality among a cohort of workers from an asbestos textile plant.

Adult↗
PubMedDate not supplied

Is enhanced fetal growth a risk factor for the development of atopy or asthma?

BACKGROUND: The aetiological factors underlying the worldwide increase in the prevalence of asthma and the international patterns of the prevalence of asthma are not well understood. This has led to consideration of factors such as fetomaternal health which may programme the initial susceptibility to allergic sensitisation, or contribute to the development of asthma independently of sensitisation. METHODS: A number of epidemiological studies have examined the relationship between birth anthropometric measures (as a marker of fetomaternal health) and the subsequent development of asthma and atopy in childhood or adult life. RESULTS: Some, but not all of these studies have reported a relationship between enhanced fetal growth and an increased risk of asthma and/or atopy. CONCLUSION: These findings raise the hypothesis that factors responsible for fetal growth may also lead to programming of the developing respiratory or immune systems, predisposing to the subsequent development of asthma and/or atopy. This hypothesis may explain, in part, the increasing prevalence of asthma and atopy over recent decades, which has occurred concurrently with secular trends for improved fetomaternal health, as measured by anthropometric measurements at birth.

Adult↗
PubMedDate not supplied

Withdrawal of fenoterol and the end of the New Zealand asthma mortality epidemic.

In response to the evidence that fenoterol was a major cause for the second epidemic of asthma deaths in New Zealand, the Department of Health severely restricted its availability, thereby allowing an 'experiment in prevention' to be undertaken. These regulatory actions, which effectively removed fenoterol from the market in New Zealand, were associated with a sudden and marked reduction in asthma mortality, providing further evidence for a causative role of fenoterol in the epidemic of asthma deaths in New Zealand.

Administration, Inhalation↗