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Biomedical subjects

R B Payne

Publications and source records attributed to R B Payne.

At least 73 records · Page 4Linked to original sources

Psychomotor reminiscence as a function of sex and length of rest period.

Sex differences in psychomotor reminiscence were examined as a function of the length of the rest period. Five groups of Caucasian subjects, each group consisting of 12 males and 12 females, practiced continuously for 3 min on a mirror-tracking task, then rested for 0,1, 2, 4, or 8 min before resuming continuous practice. Reminiscence in both sexes increased as negatively accelerated functions of the amount of rest. The asymptotic level of reminiscence was higher for females than for males, but the quadratic slopes of the two functions were essentially alike. Analyses of prerest trial gains supported a conclusion that females reminisced more because they accumulated more reactive inhibition prior to rest.

Journal Article↗

Effector localization and transfer of reactive inhibition.

An experimental test was made of Hull's (1943) notions that reactive inhibition is effector-specific and that it has primary negative motivational properties. Four groups of 20 subjects (10 males and 10 females in each) executed two segments of continuous right-hand practice on a mirror-tracking task. The two segments were separated either by 0 min rest, 5 min rest, 5 min continuous right-hand practice on rotary pursuit, or 5 min continuous left-hand practice on rotary pursuit. Effects of interpolated conditions were measured in terms of main-task reminiscence arid initial post-treatment performance. When interpolated practice was conducted with the right hand, reminiscence and post-treatment performance were significantly depressed relative to the rest effect, but not when interpolated practice was conducted with the left hand. Thus, Hull's views were supported, while competing views, such as the task specificity concept of lr and the consolidation theory of reminiscence, were impugned.

Journal Article↗

Interpretation of serum total calcium: effects of adjustment for albumin concentration on frequency of abnormal values and on detection of change in the individual.

Serum total calcium was measured in 1693 patients during a four-month period. We examined the effects of adjustment for albumin concentration on the interpretation of single measurements of serum total calcium and on the variation of series of measurements in individual patients. Markedly abnormal total calcium concentrations--2.75 mmol/l (11.0 mg/100 ml) or more, or 2.00 mmol/l (8.0 mg/100 ml) or less--were found in 115 patients, but only 24 (21%) remained markedly abnormal after adjustment for albumin. Three patients, two with malignant disease and one with primary hyperparathyroidism, had significant hypercalcaemia which was masked by hypoalbuminaemia. The serum total calcium measured on a subsequent occasion had changed 0.15 mmol/l (0.6 mg/100 ml) or more in 60 patients, but after adjustment for albumin this number was reduced to 27 (45%). The within-person standard deviation for serum total calcium was calculated in 26 patients with normal mean adjusted calcium concentrations who had had six or more sequential measurements. The mean standard deviation was 0.148 mmol/1 (0.59 mg/100 ml) and, after adjustment for albumin, this was reduced to 0.100 mmol/1 (0.40 mg/100 ml). We conclude that adjustment of serum total calcium concentration for albumin is essential to detect abnormal values and to assess changes in a value.

Blood Protein Disorders↗

Adjusted calcium conflict resolved? Differing effects on plasma total calcium of changes in plasma albumin after venous stasis or myocardial infarction.

Others have challenged the concept of adjusting total plasma calcium for albumin concentration on the grounds that after the application of a tourniquet the increase in calcium for a given increase in albumin differs significantly between normal individuals. We have confirmed this finding. In contrast, we have found that after myocardial infarction the fall in calcium for a given fall in albumin does not differ significantly between patients. Thus the adjustment of calcium for albumin using a single equation remains valid in patients with changes in albumin due to disease. We recommend that for consistent results blood should be taken with the minimum of venous stasis even though the patient's calcium is to be adjusted for albumin.

Blood Flow Velocity↗

Re-examination of effect of paracetamol on serum uric acid measured by phosphotungstic acid reduction.

The drug paracetamol (N-acetyl-p-aminophenol; acetaminophen) caused a spurious increase in serum uric acid measured by phosphotungstic acid reduction methods. However, the increase was less than 0.12 mmol/1 at plasma levels of paracetamol found in overdosage (40 mg/100 ml) and was small at therapeutic concentrations (less than 4 mg/100 ml). It is concluded that few patients with joint pain who have taken paracetamol paracetamol as an analgesic will have clinically misleading values for serum uric acid.

Acetaminophen↗

Effect of myo-inositol on peripheral-nerve function in diabetes.

myo-Inositol, 500 mg twice a day, given to seven diabetic patients for two weeks, increased the amplitude of the evoked action potentials of the median, sural, and popliteal nerves by an average of 76%, 160%, and 40%, respectively. There was no significant change in the conduction velocities of these nerves, myo-Inositol may be valuable in the treatment of diabetic neuropathy.

Aged↗

Interpretation of urinary oestrogen:creatinine ratio for monitoring fetoplacental function in late pregnancy.

In pregnancies with a normal outcome the oestrogen:creatinine ratio in early morning samples of urine showed a smaller day-to-day variation than the ratio in 24-h urine or the 24-h total oestrogen excretion, and a significant fall could be detected more easily. Patients admitted to hospital who eventually delivered a healthy baby provided a reference range which, after logarithmic transformation, increased linearly with period of gestation. A fall in log10 oestrogen:creatinine ratio exceeding 40% of this range is unusual in pregnancies with a healthy outcome, and suggest impaired fetoplacental function.

Creatinine↗

Urinary excretion of calcium in late pregnancy and its relation to creatinine clearance.

The distribution of the values for the daily urinary excretion of calcium during the last trimester of pregnancy was skewed toward high values in 1,034 women in Bradford, England. The logarithms of the values had a Gaussian distribution. The 95% range of this log-Gaussian distribution was 0.75 to 15.5 mmoles (30 to 620 mg.) per day. Nearly 20% of the values exceeded 8.75 mmoles (350 mg.) per day, which is the reported upper limit of the 95% range for nonpregnant women. Creatinine clearance is known to increase during pregnancy, and a prospective investigation in 112 pregnant Caucasian women in a hospital showed a highly significant correlation between calcium excretion and creatinine clearance. It is suggested that the increase in calcium excretion during pregnancy is due to the increase in glomerular filtration rate.

Absorption↗

Plasma creatinine and urea: creatinine ratio in patients with raised plasma urea.

We examined the plasma urea and creatinine concentrations and the ratio between them according to diagnosis in 100 unselected and 31 selected adult hospital patients with a plasma urea concentration greater than or equal to 10 mmol/l (60mg/100ml). We also examined plasma urea and creatinine concentrations in 350 unselected consecutive patients, but found no useful relation between the two values. Congestive heart failure was the most common identifiable cause of a raised plasma urea concentration in the 100 unselected patients (36%). Among these 100 patinets the plasma creatinine concentration was a more useful discriminant between prerenal uraemia and intrinsic renal failure than was the urea:creatinine ratio or the plasma urea concentration. A plasma creatinine concentration greater than 250 mumol/1 (2-8 mg/100ml) indicated intrinsic renal failure with a 90% probability.

Acute Kidney Injury↗

Transfer of reaction inhibition.

A serious challenge to Hull's (1943) theory of reminiscence and intertrial-interval effects is posed by the current contention that reactive inhibition (In) must be task-specific since it does not seem to transfer from one task to another. This notion was examined within the framework of a practice-rest paradigm in which three control groups were given 20 1-min trials on a principal task with intertrial intervals of 0, 5, and 70 sec, respectively, while two experimental groups practiced alternately on the principal task and a secondary task known to produce evidence for I(R). The two secondary tasks varied in their similarities to the principal task. Additional control groups were used to assess the magnitude of habit transfer effects. The total sample consisted of 70 males and 70 females whose modal age was 18 yr. With habit transfer effects controlled, results showed clearly that work effects transferred from the alternate tasks to the main task without regard for differences in similarity. Thus, the task-specificity hypothesis was not supported.

Journal Article↗

Sodium, water and acid-base balance: teaching transient and steady states.

We suggest that medical teaching should give greater emphasis to the interpretation of measurements in patients with chronic disturbances of homeostatic mechanisms, and some principles are outlined. The single principle which is most useful in reducing confusion is that in the steady state excretion rate is equal to intake or metabolic production rate, and rarely helps to decide the nature of a homeostatic disturbance.

Acid-Base Equilibrium↗