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Biomedical subjects

C Miles

Publications and source records attributed to C Miles.

At least 73 records · Page 4Linked to original sources
PubMed1987

The combined effects of occupational health hazards: an experimental investigation of the effects of noise, nightwork and meals.

An experimental study of the effects of noise, nightwork and meals showed that these factors influenced different aspects of performance. Speed of performing a low memory load version of a visual search task was influenced by working at night but was unaffected by either noise or meals. A high memory load version of the search task was performed more slowly after consumption of a meal, both during the day and at night, but was not influenced by nightwork. Subjects working in noise produced more errors on the high memory load task than those working in quiet, but neither nightwork nor meals had significant effects on the number of errors. The only evidence of an interaction between factors was obtained in the high memory load search task, where noise reduced the size of the post-meal decline in speed. These results show that the effects of noise, nightwork and meals are largely independent, the exception being the beneficial effect of noise on post-lunch performance. They also demonstrate that the effects of all of these factors depend on the nature of the task being performed, and on whether speed or accuracy is the variable under consideration.

Analysis of Variance↗
PubMed1987

Photoplethysmography in the assessment of venous insufficiency.

Photoplethysmography has been used simultaneously with ambulatory venous pressure measurements to study 32 patients. Of the 62 limbs studied, 24 were normal, 20 had primary varicose veins, and 18 had deep valvular incompetence. The results indicate that the photoplethysmographic refilling time can provide a good separation between the three groups when the test is performed in the standing, but not in the sitting, position. However, the test is qualitative because we found a lack of correlation between the short refilling times in limbs with deep venous insufficiency and the ambulatory venous pressure.

Blood Flow Velocity↗
PubMed1986

The interactive effects of alcohol and mood on dual-task performance.

The interactive effects of mood induction and alcohol consumption were examined in a combined visual digit detection and tracking task. Although tracking ability was independently sensitive to both time on task and alcohol, no interaction between alcohol and mood was observed. However, correct reaction times on the digit detection task were sensitive to such interactive effects. Those individuals who both consumed alcohol and watched a descriptive film performed worse on this part of the task throughout the session compared to those who watched a humorous film and did not take alcohol. Correlational analyses between performance on the tracking and digit detection tasks do not necessarily support the contention that alcohol may serve to disrupt the operation of a timesharing process.

Adolescent↗
PubMed1986

Interaction between a "processed" ovalbumin peptide and Ia molecules.

The binding of 125I-labeled immunogenic peptides to purified Ia molecules in detergent solution was examined by equilibrium dialysis. We used the chicken ovalbumin peptide ovalbumin-(323-339)-Tyr, which is immunogenic in the BALB/c mouse and restricted to I-Ad. 125I-labeled ovalbumin-(323-339)-Tyr was shown to bind to I-Ad but not to I-Ed, I-Ek, or I-Ak. This binding was inhibited by unlabeled ovalbumin-(323-339) but not by ovalbumin-(329-339), which is the longest N-terminally truncated peptide that fails to stimulate any of the I-Ad-restricted hybridomas that have been raised to ovalbumin-(323-339)-Tyr. As a further specificity control, we also used the chicken egg lysozyme peptide Tyr-(46-61), which has recently been studied by similar methods [Babbitt, B. P., Allen, P. M., Matsueda, G., Haber, E. & Unanue, E. R. (1985) Nature (London) 317, 359-361]. We have confirmed that it bound to I-Ak but not to I-Ek, I-Ad, or I-Ed. Thus, a specific interaction between Ia and antigen that correlates with the major histocompatibility complex restriction was demonstrated, strongly arguing in favor of a determinant selection hypothesis for such restriction.

Animals↗
PubMed1986

Acute effects of meals, noise and nightwork.

An experimental study of the acute effects of meals, noise and nightwork showed that there was a post-meal impairment in detection of targets in a cognitive vigilance task. This was found both during the day and at night, although certain features of the results suggested that the day and night effects were not equivalent. Noise increased the number of false alarms but reduced the post-meal impairment in hit rate. Subjects with low levels of trait or state anxiety showed the greatest post-lunch impairments in performance, but this effect was reduced when the meal was eaten at night.

Achievement↗
PubMed1986

Effects of lunch on selective and sustained attention.

Post-lunch impairments in performance efficiency have been found in both real-life settings and the laboratory. The first aim of the present experiment was to determine whether post-lunch changes in performance depend on eating a meal, or whether they are also found in subjects who abstain from eating. A second aim was to examine which aspects of performance are most likely to show post-lunch impairments. The results showed that the ability to maintain attention and react quickly to the appearance of a new stimulus was impaired following consumption of the meal. The extent of this effect did not vary with time on task, and was unaltered by changes in the time at which lunch was eaten. In contrast to this, the ability to resist distraction was unaffected by eating lunch. Other types of performance, such as movement time, varied as a function of time of day, but were not impaired by the meal.

Attention↗
PubMed1984

Heats of combustion of chemically different lipids.

The caloric content of foods listed in food composition tables, such as the USDA Agriculture Handbook No. 8, is calculated by multiplying the gram amount of the protein, fat, and carbohydrate in the food by specific caloric factors derived around the turn of the century by Atwater and co-workers. To evaluate the accuracy of these specific caloric factors, we determined the heats of combustion of vegetable oils as purchased; of lipids extracted from red meats, chicken, fish, egg yolk, and cereal grains; and of the residue (protein) left after lipid extraction of the meats. These heats of combustion were converted to available energy values by the method of Atwater . The specific caloric factors used to calculate the caloric content of foods in Agriculture Handbook No. 8 and other tables of food composition may exaggerate the calories contributed by the lipids in some foods. When the food lipid was mainly triglyceride, the available energy values calculated in this study were within 2% of the specific factors used in Agriculture Handbook No. 8. However, when the food lipid had a high content of phospholipid, our calculated available energy values were lower than the specific factors used currently. The energy content of the fat-free residue (protein) of meat, poultry, and fish was also less than that currently used for those foods in food composition tables.

Animals↗
PubMed1983

Intermittent sequential pneumatic compression of the legs and thromboembolism-deterrent stockings in the prevention of postoperative deep venous thrombosis.

One hundred fifty patients over the age of 30 who had undergone major abdominal operations were stratified according to the risk of deep venous thrombosis and randomized into three groups to receive different prophylactic regimens: group A, electrical calf stimulation; group B, low-dose subcutaneous heparin; group C, intermittent sequential compression and thromboembolism-deterrent (TED) stockings. All the patients were scanned with the 125I-fibrinogen test for the whole stay in hospital. The incidence of 125I-fibrinogen detected deep venous thrombi was 18% in group A, 9% in group B, and 4% in group C. The results indicate that the regimen of intermittent sequential compression and TED stockings is as effective as low-dose subcutaneous heparin. Electrical calf stimulation is less effective.

Abdomen↗
PubMed1982

The effect of local cooling on digital systolic pressure in patients with Raynaud's syndrome.

The effect of local controlled cooling on the digital systolic blood pressure in the hand was studied in 25 healthy volunteers and 25 patients with Raynaud's syndrome. Arterial systolic pressure was indirectly measured using a digital cuff over the proximal phalanx and a photoplethysmographic probe over the digital pulp to detect pulsation. Pressures were measured after occlusion of the circulation (cuff at 180 mmHg) for 5 minutes with water circulating initially at 30 degrees C and then at 10 degrees C. An air filled cuff was used simultaneously on a control finger. The digital systolic pressure at 10 degrees C in the patients was significantly lower (P less than 0.001 Mann-Whitney U test) than in the normal volunteers whilst calculation of the percentage change in pressure induced by cooling the digit to 10 degrees C allowed complete separation between both groups. The range in the controls was +2 per cent to -26 per cent and in the patients, -33 per cent to -100 per cent. The test gives reproducible results (coefficient of variation 5-11 per cent) and offers an objective method of identifying patients with excessive vasospasm due to a cold stimulus. It may prove useful in studying natural history and the effect of drug therapy.

Adult↗
PubMed1979

Significance of popliteal reflux in relation to ambulatory venous pressure and ulceration.

Fifty-one patients (55 limbs) who had had deep venous thrombosis (DVT) extending into the femoral or iliofemoral segment three to five years earlier and ten limbs of ten healthy volunteers were studied. The ambulatory venous pressure (AVP) was measured by inserting a needle in a vein on the foot; the presence of reflux in the popliteal vein was determined by a directional Doppler ultrasonic blood velocity detector. All patients had ascending venography. The results suggest that the most important factor in determining the AVP and ulceration in postthrombotic limbs is the condition of the popliteal valves. Ulceration does not occur even in the presence of occlusion if the popliteal valves are competent. The extent of DVT and recanalization or the failure of recanalization is of secondary importance.

Humans↗
PubMedDate not supplied

Structural characteristics of an antigen required for its interaction with Ia and recognition by T cells.

A detailed analysis of the residues within an immunogenic peptide that endow it with the capacity to interact with Ia and to be recognized by T cells is presented. Ia interacts with only a few of the peptide residues and overall exhibits a very broad specificity. Some residues appear to interact both with Ia and with T cells, leading to a model in which a peptide antigen is 'sandwiched' between Ia and the T-cell receptor.

Amino Acid Sequence↗