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Biomedical subjects

D Clayton

Publications and source records attributed to D Clayton.

108 records · Page 6Linked to original sources
PubMed1984

Infant feeding in Nigeria.

A study by questionnaire of 1845 urban and 349 rural mothers in all regions of Nigeria is reported. 99% of all mothers commenced breastfeeding their infants. In urban areas most continued for at least 6 months and in rural areas for at least 12 months. In urban areas, 77% of the infants were given infant formula by the age of 3 months; in rural areas 40% were given infant formula. Cereals were also introduced early to many children. The reasons for and the effects of this pattern of infant feeding are not clear, but it presumably meets the overall needs of the population. Further investigation is needed before attempts are made to enforce change.

Africa↗
PubMed1983

Asthma due to Central American walnut (Juglans olanchana) dust.

The purpose of our study was to describe a case of asthma due to Central American walnut (Juglans olanchana) dust and to ascertain whether an IgE antibody mechanism was implicated. The subject was a 48-year-old man who developed asthma following exposure to Central American walnut dust. Although intradermal testing with an aqueous extract of walnut dust produced no response, inhalation challenge with the extract produced significant bronchoconstriction. Another asthmatic person exposed to the wood dust had a positive skin test, but did not respond to the bronchial challenge. A direct radioallergosorbent test (RAST) on both subjects showed no evidence of serum IgE antibodies to Central American walnut dust. Consequently, the mechanism responsible for the sensitivity to the walnut dust remains unknown.

Asthma↗
PubMed1981

The design and interpretation of case-control studies of perinatal mortality.

The difficulty of designing prospective studies of perinatal death makes the case-control study a method of choice. The particular problems associated with the identification of risk factors, the definition and enumeration of cases, and the selection of live birth controls in such a study, undertaken on all perinatal deaths occurring in a population of 850,000 people during 1976-1978 are described. The method of control selection, chosen for reasons of feasibility, produced a nonrepresentative sample of controls. This was because controls were selected as the next live birth in the place of delivery where the perinatal death delivery occurred, which resulted in a sample stratified by place of delivery. Knowledge of the place of delivery of all births allowed a correction to be undertaken which was derived from the relative weights for the strata within which matching had occurred.

Data Collection↗
PubMed1981

The bioavailability of erythromycin stearate versus enteric-coated erythromycin base when taken immediately before and after food.

1. Erythromycin plasma concentrations were determined in twenty subjects after a single dose, immediately before food, of erythromycin, 500 mg. as: (1) erythromycin stearate (Erythrocin, 500 mg, ovaloid tablets), and (2) erythromycin base (Eryc, 250 mg, capsules containing enteric-coated pellets). 2. Plasma concentrations were again determined in eighteen of the original subjects with the same dose given immediately after food. 3. Maximum Plasma Concentrations (mcg/ml) (See formula in text) 4. Erythromycin stearate was more bioavailable than erythromycin base when administered immediately before food. The preparations were bioequivalent when given immediately after food.

Biological Availability↗
PubMed1980

Myocardial infarction and water hardness in European towns.

The negative association between water hardness and cardiovascular disease found by several authors in different countries has also been found in the present investigation. All cases of myocardial infarction were registered in a standardized way at 15 WHO Collaborating Centres in Europe; information on the hardness of drinking water used by the population studies was also collected. Higher rates of myocardial infarction were usually found in towns served by softer water.

Climate↗
PubMed1979

Myocardial infarction and water hardness in the WHO myocardial infarction registry network.

The negative association between water hardness and cardiovascular disease found by several authors in different countries has also been found in the present investigation. All cases of myocardial infarction were registered in a standardized way at 15 WHO Collaborating Centres in Europe; information on the hardness of drinking water used by the population studied was also collected. Higher rates of myocardial infarction were usually found in towns served by softer water.

Aged↗
PubMed1975

Coronary heart-attacks in East London.

All cases of cardiac infarction, acute coronary insufficiency and sudden death occurring in residents of the London Borough of Tower Hamlets below age 65 were registered over nearly three years, and survivors were followed up for one year. The attack-rate in men aged 45-64 years was 1 per 100 per annum but the recurrence-rate in survivors was 1 per 100 per month. Immigrants from Asia had more than the average, and those from the Carribean one tenth of the average attack-rate. Although it was unusual for general practitioners to manage cases at home by choice, nonetheless two-thirds of the deaths happened outside hospital and half of these were not witnessed. Half of those suffering coronary heart-attacks had a previous history of coronary disease and a sizable minority were already unfit for work. Approximately half of those attacked were alive at one year.

Acute Disease↗
PubMedDate not supplied

Latent class analysis in chronic disease epidemiology.

Latent class analysis provides a useful framework for the analysis of epidemiological data which may have been mismeasured. In this paper, the latent class model is described in the context of logistic regression with categorical variables, and some examples of its application are provided. In particular, it is shown that adjustment for a misclassified confounding variable can be greatly improved by using the methods presented.

Chronic Disease↗
PubMedDate not supplied

Using test-retest reliability data to improve estimates of relative risk: an application of latent class analysis.

The paper discusses the problem of interval estimation for the relative risk when some test-retest data are available on random subsamples drawn from case-control studies. It is shown that, although the upper portion of the interval may be very wide indeed, the lower bound of the interval estimate may be improved considerably by the collection of even modest amounts of repeat measurements.

Disease↗
PubMedDate not supplied

Bayesian estimates of disease maps: how important are priors?

In the fully Bayesian (FB) approach to disease mapping the choice of the hyperprior distribution of the dispersion parameter is a key issue. In this context we investigated the sensitivity of the rate ratio estimates to the choice of the hyperprior via a simulation study. We also compared the performance of the FB approach to mapping disease risk to the conventional approach of mapping maximum likelihood (ML) estimates and p-values. The study was modelled on the incidence data of insulin dependent diabetes mellitus (IDDM) as observed in the communes of Sardinia.

Bayes Theorem↗
PubMedDate not supplied

Bayesian analysis of space-time variation in disease risk.

The analysis of variation of risk for a given disease in space and time is a key issue in descriptive epidemiology. When the data are scarce, maximum likelihood estimates of the area-specific risk and of its linear time-trend can be seriously affected by random variation. In this paper, we propose a Bayesian model in which both area-specific intercept and trend are modelled as random effects and correlation between them is allowed for. This model is an extension of that originally proposed for disease mapping. It is illustrated by the analysis of the cumulative prevalence of insulin dependent diabetes mellitus as observed at the military examination of 18-year-old conscripts born in Sardinia during the period 1936-1971. Data concerning the genetic differentiation of the Sardinian population are used to interpret the results.

Adolescent↗
PubMedDate not supplied

Hemofiltration in a cardiac intensive care unit: time for a rational approach.

The typical annual expenditure for patients requiring continuous hemofiltration (CHF) is high. To audit the benefit of this expensive treatment, the outcome of 48 consecutive patients (34 men, 14 women; mean age, 65 years) requiring hemofiltration for acute renal failure was analyzed during a period of 24 months. The operations performed were 26 CABG, 8 AVR, 3 AVR/MVR, 2 post infarction VSD repairs, and 1 thoracoabdominal aneurysmectomy. Indications for hemofiltration were oliguria and fluid overload in 69%, uremia in 56%, acidosis in 33%, and hyperkemia in 13%. Twenty five patients (52%) died while in the hospital, and 10 more died within 9 months of discharge. Of the remaining 13 survivors, 6 (46%) were classified as III or IV according to the New York Heart Association classification system. The mean ITU and hospital stay per patient requiring CHF was 15.3 days and 25.4 days, respectively. There were no statistically significant differences between patients who did and did not survive in the hospital in age, pre-operative renal function, ejection fraction, duration of cardiopulmonary bypass, or urine output before CHF. However, there were no survivors when the cardiac index was less than 1.7 L/m2 and adrenalin requirement was more than 30 micrograms/min before CHF (seven patients). These results suggest that the short- and long-term outcome in patients requiring CHF after cardiac surgery is poor. Considering the large demand on resources, the use of CHF should be rationalized, particularly in patients with persistent low cardiac output.

Acute Kidney Injury↗