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Biomedical subjects

A Young

Publications and source records attributed to A Young.

At least 325 records · Page 18Linked to original sources

Anti-globulins and circulating complexes in early rheumatoid arthritis.

The importance of immunological parameters such as anti-globulins, anti-RANA and circulating immune complexes in rheumatoid arthritis (RA) has been studied by examining patients with early disease who are attending general practitioner clinics with joint pains for the first time. Anti-RANA, and IgG and IgM anti-globulins were detectable in the serum at the earliest time we were able to examine the patients. The anti-globulins had specificity for both rabbit and human IgG from the outset. Immune complexes were similarly raised in early disease. From these patients with early joint pains we were able to predict, by means of multivariant discriminant analysis of the laboratory data obtained from the first serum sample, between those who would develop into patients with classical or definite RA at 1 year and those who would have non-inflammatory joint disease.

Antibodies, Anti-Idiotypic↗

The effect of knee injury on the number of muscle fibres in the human quadriceps femoris.

By means of ultrasound scanning, bilateral measurements of the cross-sectional area of the quadriceps muscle groups were made in 14 young adults with unilateral thigh muscle wasting after knee injury. Needle biopsy specimens from the lateral mass of the muscle were used to estimate the myofibre cross-sectional area for both quadriceps of each subject. 2. The cross-sectional area of the quadriceps of each patient's injured limb was always smaller than that of the contralateral muscle. The wasting was largely localized to the quadriceps, with relative sparing of the other thigh muscles. 3. None of the biopsies showed any abnormality apart from the reduction in fibre size. In each case, the injured limb's reduced quadriceps cross-sectional area was associated with a reduced mean fibre area. 4. The ratio of the cross-sectional area of a muscle to its mean fibre area is a reduced mean fibre area. 4. The ratio of the cross-sectional area of a muscle to its mean fibre area is a function of the number of fibres it contains. The ratio varied considerably from patient to patient but there was close agreement between the values obtained for the two limbs of each patient. 5. The quadriceps wasting produced by knee injury was due to muscle fibre atrophy. There was no evidence for a change in the number of fibres in the muscle.

Adult↗

The value of postcardiac infarction exercise stress testing: identification of a group at high risk.

We prospectively selected 154 patients who had survived acute myocardial infarction with electrical and/or mechanical complications to undergo an exercise stress test, four to six weeks after discharge from the Coronary Care Unit, Royal Melbourne Hospital. The patients exercised on a bicycle ergometer until they were unable to continue or had reached 70% of their predicted maximum heart rate for their age. Eighteen (11.7%) patients exhibited flat ST-depression of 1 mm or more on exercise. Six of these 18 patients later died (33.3%). Only seven (5.1%) of the 136 patients who exhibited no electrocardiographic change died during follow-up. We conclude that patients recording positive exercise stress test results after acute myocardial infarction, have a poorer prognosis and therefore should be considered for more intensive medical or surgical treatment.

Arrhythmias, Cardiac↗

When rational men fall sick: an inquiry into some assumptions made by medical anthropologists.

Medical anthropologist spend most of their time eliciting and interpreting people's statements about sickness and health. For this task, they make certain assumptions about the importance of language and reason. In this paper I argue that their assumptions are tailored to fit an hypothetical Rational Man rather than real people. The concept of 'explanatory models of sickness' is used to illustrate this point. My critique begins by drawing attention to two non-cognitive determinants of people's statements: their degree of emotional arousal and their capacities for discoursing on medical subjects. These determinants are briefly discussed and then set aside, to make room for the paper's argument proper. This starts with the observation that medical anthropologists tend to overlook the fact that they have established a cognitive no man's land stretching between their informants' statements and the cognitive structures which are supposed to generate these statements. I survey this void, using a five-fold model of medical knowledge. People use one kind of knowledge to organize their medical experiences and perceptions. In Rational Man writing, this form of knowledge is considered equivalent to cognitive structures (e.g., causal models, classificatory schemes), but I argue that is also includes knowledge of prototypical sickness events and knowledge that is embedded in actions, social relations, and material equipment. The theoretical implications of the five-fold model are outlined. This is followed by an analysis of the reasoning processes in which people use medical knowledge to produce the statements whose meaning we wish to learn. I demonstrate the importance of being able to distinguish operational and monothetic forms of reasoning from pre-operational and polythetic ones. Rational Man writers are described as ignoring the latter pair. The concept of 'prototypes' is reintroduced to illustrate these points.

Adaptation, Psychological↗

Cauda equina syndrome complicating ankylosing spondylitis: use of electromyography and computerised tomography in diagnosis.

A case of the cauda equina syndrome complicating ankylosing spondylitis (AS) is described. An unusual feature of this case was the relapsing and remitting nature of the condition, but there is sufficient evidence to explain the clinical picture on the basis of a recurrent intraspinal inflammatory process. The clinical and radiological features are similar to those of a further 28 reported in the literature. An electromyogram (EMG) proved important in defining the extent of neurological involvement. Computerised tomography (CT) showed marked laminar erosion and no bony exit foramen encroachment. We believe that the clinical diagnosis of this condition can be adequately confirmed with plain radiology, EMG, and CT scan.

Aged↗

Maximum leg force and power output during short-term dynamic exercise.

Force exerted and power generated were measured during short-term exercise performed on a bicycle ergometer that had been modified by the addition of an electric motor driving the cranks at a chosen constant velocity. Five subjects made a series of 20-s maximum efforts at different crank velocities (range 23--171 rev/min). The forces exerted were continuously monitored with strain gauges bonded to the cranks. Peak force was exerted at approximately 90 degrees past top dead center in each revolution. During the 20-s effort peak force declined from the maximum level (PFmax) attained near the start of exercise, the rate of decline being velocity dependent. PFmax was found to be inversely and linearly related to crank velocity and when standardized for upper leg muscle (plus bone) volume (ULV) was given by PFmax (kgf/l ULV) = 27.51--0.125 crank velocity (rev/min). Integration of the force records with pedal velocity enabled power output to be calculated. Maximum power output was a parabolic function of crank velocity, the apex of the relationship indicating that the velocity for greatest power output was 110 rev/min. At this velocity our subjects achieved a maximum mean power output, averaged over a complete revolution, of 840 +/- 153 W (85 +/- 5 W/l ULV). This was compared with the calculated value for maximum mechanical power output from aerobic sources, which was 272 +/- 49 W (30 +/- 1 W/l ULV).

Adult↗