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Biomedical subjects

A Smith

Publications and source records attributed to A Smith.

At least 1,243 records · Page 69Linked to original sources
PubMed1981

Intestinal alkaline phosphatase in bile: evidence for an enterohepatic circulation.

The isoenzyme characteristics of alkaline phosphatase in human bile obtained from patients with gallstones have been determined by means of electrophoresis on polyacrylamide gel, both before and after preincubation with neuraminidase, and also by means of inhibition tests with heat, urea, and L-phenylalanine. Bile alkaline phosphatase is shown to be partly secreted by the liver cell, but partly derived from the small intestine. The presence of small-intestinal alkaline phosphatase in bile implies an enterohepatic circulation of this high molecular weight glycoprotein. The significance of this finding is discussed in relation to the mechanism whereby large protein molecules may pass across the plasma membrane of the liver cell.

Alkaline Phosphatase↗
PubMed1981

Relative humidity and manic admissions in the London area.

This report describes an investigation into a possible relationship between barometric pressure and relative humidity, and depressive and manic admissions in the London area. A negative correlation between manic admissions and relative humidity was observed when the data were examined in several ways.

Affective Disorders, Psychotic↗
PubMed1981

Relation of particle dimension to carcinogenicity in amphibole asbestoses and other fibrous minerals.

In 72 experiments, durable minerals in the form of particles on respirable size and of wide chemical and structural varieties, were implanted in the pleurae of outbred female Osborne- Mendel rats for periods of more than 1 year. The incidence of induced malignant mesenchymal neoplasms correlated well with the dimensional distribution of the particles. The probability of pleural sarcoma correlated best with a number of fibers that measured 0.25 micro or less in diameter and more than 8 micrometer in length, but relatively high correlations were also noted with fibers in other size categories having diameters up to 1.5 micrometer and lengths greater than 4 micrometer. Morphologic observations indicated that short fibers and large-diameter fibers were inactivated by phagocytosis and that negligible phagocytosis of long, thin fibers occurred. The wide variety of compounds used in these experiments suggested that the carcinogenicity of fibers depended on dimension and durability rather than on physicochemical properties.

Animals↗
PubMed1981

Progress in malaria vector control.

Malaria control, except in tropical Africa, will probably continue to be based to a large extent on the use of insecticides for many years. However, the development of resistance to insecticides in the vectors has caused serious difficulties and it is necessary to change the strategy of insecticide use to maximize their efficacy. A thorough knowledge of the ecology and behaviour of each vector species is required before the control strategy can be adapted to different epidemiological situations. The behavioural differences between sibling species have been recognized for several years, but study of this problem has recently been simplified by improved means of identification that involve chromosomal banding patterns and electrophoretic analysis. Behavioural differences have also been associated with certain chromosomal rearrangements.New records of insecticide resistance among anophelines continue to appear and the impact of this on antimalaria operations has been seriously felt in Central America (multi-resistance in Anopheles albimanus), Turkey (A. sacharovi), India and several Asian countries (A. culicifacies and A. stephensi), and some other countries. Work continues on the screening and testing of newer insecticides that can be used as alternatives, but DDT, malathion, temephos, fenitrothion, and propoxur continue to be used as the main insecticides in many malaria control projects. The search for simpler and innovative approaches to insecticide application also continues.Biological control of vectors is receiving increased attention, as it could become an important component of integrated vector control strategies, and most progress has been made with the spore-forming bacterium, serotype H-14 of Bacillus thuringiensis. Larvivorous fish such as Gambusia spp. and Poecilia spp. continue to be used in some programmes.Application of environmental management measures, such as source reduction, source elimination, flushing of drainage and irrigation channels, and intermittent irrigation have been re-examined and currently a great deal of interest is being shown in these approaches.There has been limited interest in the genetic control of mosquitos and the phenomenon of refractoriness in some strains of the disease vectors, with the idea of replacing the vector species with the refractory strain. More research is needed before this approach can become a practical tool.It is apparent that in future a more integrated approach will have to be used for vector control within the context of antimalaria programmes. Training of staff, research, and cooperation at all levels will be an essential requirement for this approach.

Animals↗
PubMed1981

Digital scintigraphy: principles, design, and performance.

In a digital camera the position of a scintillation event is computed following analog-to-digital conversion of photomultiplier pulse charges. Digital position analysis is essentially a mathematical inversion procedure based upon calibrated responses of the photomultipliers to scintillations from a narrow-beamed source that maps a detector's field of view. Operationally, a camera's image characteristics are optimized by means of computer-generated inversion reference tables, individually tailored to the specific response characteristics of each detector. Design considerations indicate that cameras of varied configurations, e.g., linear, disc-shaped, rectangular, or cylindrical, can be analyzed by this method. Also, for any given electro-optical system, energy resolution, spatial characteristics, and event-rate performance can be made superior to analog systems. The measured performances of a one-dimensional test camera, although limited in its optical and electronic design, support this conclusion.

Analog-Digital Conversion↗
PubMed1981

Stuttering: in need of a unifying conceptual framework.

Perceptually fluent and disfluent speech reflect a continuum of coordination and can be best understood in terms of similar motor control processes. Speech movements may be considered to result from the interaction of inputs to motoneuron pools which alter the tuning of sensory-motor pathways and triggering inputs to specific muscles and muscle groups. A disorder incoordination may occur when any of these inputs is aberrantly affected by psychological, psychosocial or physiological variables. Specific phenomena associated with stuttering--adaptation, masking, whispering and voicing deviations--are interpreted in terms of these neuromotor processes. Therapeutic considerations are discussed.

Biomechanical Phenomena↗
PubMed1981

Use of 2-allyl-2-isopropylacetamide as a catalytic site probe for rabbit cytochrome P-450.

The porphyrinogenic agent, 2-allyl-2 isopropylacetamide (AIA was used as a catalytic site-specific probe for the inducible forms of rat and rabbit cytochrome P-450. The loss of specific enzyme activities associated with forms 2, 4 and 6 of rabbit liver microsomal cytochromes P-450 clearly showed that AIA not only inhibits the benzphetamine N-demethylase activity of form 2 (the major form induced by phenobarbital) but also the 7-ethoxyresorufin O-deethylase activity of form 4 (the major form induced by 2, 3, 7, 8 tetrachlorodibenzo-p-dioxin, TCDD). AIA does not appear to react directly with either form 4 or form 6 but requires prior activation by the action of at least one component of PB-microsomes, probably the form 2 cytochrome P-450, before interacting with the form 4 cytochrome.

Acetamides↗
PubMed1980

Health and safety--9. foam--the critical two minutes.

The recently published Home Office report on the Woolworth's fire in Manchester, in May 1979, which involved furniture containing polyurethane (PU) foam, must inevitably re-open the debate on whether this material should be used for hospital mattresses. A. Smith outlines the arguments.

Bedding and Linens↗
PubMed1980

Health and safety--8: offices--new laws for old.

Who actually remembers anything about the Offices, Shops and Railway Premises Act? It came into operation in 1964 and was introduced to the NHS by Circular HM(64)46. The Health and Safety at Work Act is intended eventually to replace the OSRPA together with other earlier safety legislation. A. Smith jogs our memories.

Accident Prevention↗
PubMed1980

Health and safety--4: don't play with fire.

Continuing his autumn series of health and safety Mr A. Smith turns his attention to fire precautions. He talks about organisation and arrangements which exist in hospitals to ensure that all precautions are taken, that staff are trained and that the Health and Safety at work Act is observed.

Accident Prevention↗