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Biomedical subjects

J R Ashford

Publications and source records attributed to J R Ashford.

At least 19 recordsLinked to original sources
PubMed1977

Hospital activity analysis: a source of information about serial hospital admissions.

This paper describes a method for linking serial hospital admissions for the same patient on the basis of existing Hospital Activity Analysis data. Details are given of a linkage procedure suitable for use with a computer, which takes account of possible errors in the recording of items of personal information. Applications of the procedure to give the clinician better access to information about previous hospital admissions and as a basis for monitoring the effectiveness of particular hospital-based procedures are described.

Computers↗
PubMed1976

Aspects of the epidemiology of suicide in England and Wales.

This paper is concerned with the variations in suicide rates in the 161-171 local authorities in England and Wales during the 11-year period 1961-71. Analysis of the overall secular trends shows that the rates for both males and females reached a peak in 1963 and subsequently declined at a steady rate. Virtually the whole of this reduction is associated with the fall in the number of poisonings by domestic gas. Suicide rates were about 50 per cent higher in males than in females and tended to increase with increasing age and, in general, were higher in the county boroughs than in the (more rural) county authorities. There is a marked variation in terms of geographical area, with the highest rates being reported in the London and South-East Region and the lowest rates in the South-East Wales and Northern Regions. There are also systematic differences between the various conurbations, with the highest rates in London and South-East Lancashire and the lowest in Merseyside and the West Midlands. The variations between individual local authorities are then considered and it is shown that as much as 99 per cent of the total variation can be explained in terms of a small number of variables which represent the general characteristics of the the local authority and the population. The most important of these variables is the proportion of single-person housegolds, which accounts for about three-quarters of the variation in the male suicide rates and more than half of the variation in female suicide rates. The significance of these results is discussed, with particular reference to the effect of the detoxification of the domestic gas supply during the period of study.

Adolescent↗
PubMed1975

Drug interactions: the effects of alcohol and meprobamate applied singly and jointly in human subjects. III. The concentrations of alcohol and meprobamate in the blood and their effects on performance; application of mathematical models.

The relations between the levels of alcohol and meprobamate in the blood and performance on a visual-motor coordination tracking task were analyzed by a general system of mathematical models, using data from Experiment V by Carpenter et al. [J. Stud. Alc., Suppl. No. 7, pp. 54-139, 1975]. The derivation of the models is described. In general, the relationship between blood alcohol concentration (BAC) and performance was nonmonotonic: best performance occurred at BACS of 10 to 20 mg per 100 ml. The relationship between meprobamate concentration (BMC) and performance was monotonic: performance deteriorated with increasing BMC. The results of the reaction latency measure, howevr, showed no consistent relationship with BAC or BMC. The action of alcohol can be represented by a model which involves 2 distinct sites of action; that of meprobamate, 1 site. It could not be determined whether the site of action of meprobamate is distinct from those of alcohol because the blood levels of the drugs were not high enough. The implications of the results are discussed, with particular reference to the quantitative description of the joint action of drugs and the design of future experiments.

Drug Combinations↗
PubMed1975

Drug interactions: the effects of alcohol and meprobamate applied singly and jointly in human subjects. IV. The concentrations of alcohol and meprobamate in the blood.

The absorption and elimination of alcohol and meprobamate from the blood during Experiments IV (E-IV) and V (E-V) of Carpenter et al. [J. Stud. Alc., Suppl. No. 7, pp. 54-139, 1975] were studied by means of mathematical models representing the relation between doses, concentration in the blood and time elapsing since drug ingestion. The blood concentrations of samples taken 2 and 5.5 hr after beginning to drink in E-IV and 1, 1.5, 2, 2.5, 3.5 and 4.5 hr in E-V were analyzed. The presence of meprobamate did not affect blood alcohol concentration (BAC) in either experiment. At 2 hr the mean BACS after 0.25, 0.50, 0.75 and 1.00 g of alcohol per kg were 6.8, 20.9, 37.7 and 53.7 mg per 100 ml in E-IV; 5.0, 34.1, 42.0 and 72.0 mg per 100 ml in E-V; and 8.1, 32.6, 41.3 and 71.3 mg per 100 ml when calculated by regression from E-V data. The calculated elimination rate of the 2 highest doses of alcohol in E-IV was 6.0 and 7.1 mg per 100 ml per hr; in E-V the mean calculated rates after 0.25-0.75 and after 1.00 g of alcohol per kg were 6.6 and 11.0 mg per 100 ml per hr. The blood meprobamate concentrations (BMC) in E-IV were not affected by alcohol. In E-V, 2.5 and 5.5 hr after meprobamate administration, the combination of 28 mg of meprobamate per kg and 0.75 g of alcohol per kg resulted in significantly lower BMC (7.83 and 12.63 mug per 100 ml) than after same dose of meprobamate with the other doses of alcohol (14.23 and 20.02 mug per 100 ml). The differences between these results and the findings of Carpenter et al. are discussed.

Dose-Response Relationship, Drug↗
PubMed1975

Drug interactions: the effect of alcohol and meprobamate applied singly and jointly in human subjects. V. Summary and conclusions.

The design, analysis and conclusions of the series of experiments by Carpenter et al., Ashford and Cobby, and Cobby and Ashford [J. Stud. Alc., Suppl. No. 7, pp. 54-176, 1975] are reviewed. Mathematical models of the joint action of drugs were developed and data obtained to test the models by studying the action of alcohol and meprobamate singly and in combination in human subjects. The data proved to be too limited in the range of drug concentrations in the blood necessary to identify the single most appropriate model. Carpenter et al. analyzed the data by analysis of variance, which involves assumptions about the structure of the observation and the form of the distribution of the error terms. The analyses of Ashford and Cobby and Cobby and Ashford used the mathematical models, which represented pharmacological and physiological actions of the drugs. The majority of the results of the two analyses agreed; however in Experiment V Carpenter et al. combined drugs, doses and blood samples in one analysis anf found a significant influence of meprobamate dose on blood alcohol concentration (BAC) and homogeneous error terms. Cobby and Ashford analyzed absorption and elimination phases of each alcohol dose separately and found no influence of meprobamate on BAC and significant heterogeneity in the residual error terms. Both sets of analyses found a complex interaction between the pattern of abosorption and elimination of meprobamate and dose of alcohol. Carpenter et al. related the results of behavioral measures to drug doses, Ashford and Cobby to the concentrations of the drugs in the blood. Theoretically the models can analyze the pattern of behavioral results at each combination of doses but the data available were insufficient for the purpose. The modifications in experimental design and analytical techniques necessary to continue research in developing mathematical models are discussed.

Behavior↗