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Biomedical subjects

A Goode

Publications and source records attributed to A Goode.

At least 19 recordsLinked to original sources
PubMed2000

Moving out of the laboratory: does nicotine improve everyday attention?

The most robust demonstrations of the nicotine-related performance effects on human cognitive processes are seen in tasks that measure attention. If nicotine does have some potential for enhancing attention, the obvious question to ask is whether the effects demonstrated in the laboratory hold any significance for real-life performance. This paper describes three studies that compare the effects in smokers of a single own brand cigarette on laboratory tests of attention and on everyday analogues of these laboratory tasks. In the laboratory measures of sustained attention and in the everyday analogue, performance advantages were registered in the smoking condition. These benefits were observed in smokers who abstained for a self-determined period of not less than 2 h. The studies were unable to replicate previous research reporting positive effects of smoking on a laboratory task of selective attention, the Stroop task. Small but significant improvements in performance were registered in the everyday analogues, which involved sustaining attention in a dual task situation, a telephone directory search task and a map search task. In addition, smokers showed a significant colour-naming decrement for smoking-related stimuli in the Stroop task. This attentional bias towards smoking-related words occurred independent of whether they had abstained or recently smoked an own brand cigarette. The effect is discussed in terms of the two-component model of processing bias for emotionally valenced stimuli.

Adolescent↗
PubMed1997

A computer-interfaced vertometer system for contact lenses.

BACKGROUND: The conventional vertometer (lensometer) is difficult to use for accurate measurement of contact lenses whose back vertex power (BVP) varies across the optic zone. BVPs of multifocal rigid and soft contact lenses have previously been measured using a conventional vertometer incorporating the Scheiner principle, which makes use of two light paths equidistant from the center of the lens. METHODS: We have developed a computer-based vertometer system based on the Scheiner principle which can be used to produce a profile of BVPs across rigid and soft contact lenses. A computer interface to the vertometer allows rapid acquisition of readings and software-based ray tracing derives in-air dioptric power readings across the optic zone at specific ray heights. RESULTS: Results are presented for soft and rigid, and spherical and aspheric surface contact lenses. CONCLUSIONS: The system improves the measurement resolution of a standard vertometer and shows an acceptable level of precision and accuracy for most applications.

Contact Lenses↗
PubMed1996

Comparison of immunological changes between subcutaneous and intravenous route of administration of IL-2 in cancer patients.

The effects of the route of administration of interleukin 2 (IL-2) on the immunological parameters of patients with various malignancies were investigated. The percent mean values for IL-2 receptor (Tac) positive cells among mononuclear cells in patients receiving IL-2 subcutaneously (5 cases) or intravenously (6 cases) were 7 and 7%, respectively. The corresponding values of post-IL-2 treatment peak were 18 and 16%. Similarly, the values for class II antigen expressing cells were 12 and 16% and 25 and 26%. In no case the difference between the values for the subcutaneous or the intravenous route reached significance. Using the 51Cr release assay, the mean percent killing activity of IL-2-activated mononuclear cells against Daudi tumour target cells for the subcutaneously and the intravenously treated groups were 27 and 14% and the corresponding values for the post-IL-2 treatment peak were 59% (p > 0.05) and 69% (p > 0.05), respectively. The similar values using K562 tumour as target were 17 and 8%, and the corresponding values for post-treatment peak were 55% (p > 0.05) and 23% (p > 0.05). In all cases the cytotoxic values for the post-IL-2 treatment were significantly greater than the pre-IL-2 values. The mean (+/- SD) values for serum beta2-m levels for 6 subcutaneously and 5 intravenously IL-2-treated patients were 6.5 +/- 4.6 and 5.7 +/- 3.4 mg/l (p > 0.05). The corresponding values for post-IL-2 (15 days) were 9.1 +/- 3.4 and 9.9 +/- 5.1 mg/1, respectively. These results demonstrate that there is no significant difference in the immunological parameters in cancer patients receiving IL-2 via subcutaneous or intravenous routes and provide further support for the current trend for clinical trials to concentrate on outpatients subcutaneous administration.

Biomarkers↗
PubMed1994

Steady-state accommodation response and VDT screen conditions.

Steady-state accommodation response was measured for seven different visual display terminal (VDT) screen conditions and a hard-copy control condition. The screen conditions included variations in screen polarity, contrast and chromatic characteristics of the text and background. Accommodation response was measured for seven young subjects using a free-space infrared optometer, the Canon Autoref R-1. The accommodation response was measured every 1.3 s over a period of 60 s for each test condition, and both the mean and standard deviation of the responses were derived. A small but significantly higher accommodation response was found for hard copy, blue-on-red and red-on-blue screen conditions compared with white-on-black, green-on-black and black-on-white screen conditions. Screen polarity and contrast had little effect on accommodation response for the black-and-white screen conditions. The variability of accommodation response showed little difference between test conditions. For short-term VDT screen viewing, the accommodation response appears to be relatively accurate and stable across a wide range of screen conditions.

Journal Article↗
PubMed1994

Interocular blur suppression and monovision.

The ability of the binocular system to suppress blur from the defocused eye is an important mechanism underlying the success of monovision correction. With a group of 60 new monovision wearers, we found that blur suppression ability varied substantially between subjects and that crossed dominance influenced blur suppression ability. Symptoms of ghosting amongst the monovision wearers appeared to be influenced by the strength of rivalry dominance. An understanding of the suppression processes underlying monovision may assist in patient selection and management.

Anisometropia↗
PubMed1993

Distance visual acuity and monovision.

We have investigated aspects of visual acuity with monovision correction. Binocular distance visual acuity with monovision was approximately equal to monocular visual acuity for addition powers (monocular defocus) of +1.00 to +2.50 D, using both high and low contrast logMAR visual acuity charts. Neither the eye chosen to be defocused (dominant or nondominant) or pupil size (3.5, 5 and 7 mm) affected the binocular visual acuity loss with monovision for high contrast charts. We also investigated the effect of induced residual astigmatism (+0.50, +1.00, and -1.00 D) on binocular distance visual acuity in monovision correction. Residual astigmatism caused a significantly greater reduction of binocular visual acuity in the monovision condition than it did in normal binocular conditions. This effect appears to be related to a process of meridional interocular suppression. It may therefore be of clinical importance to correct low amounts of residual astigmatism in monovision corrections to provide optimum binocular visual acuity.

Adult↗
PubMed1987

Effects of variation of the tri-iodothyronine/reverse triiodothyronine ratio in vivo on the metabolic characteristics of subsequently isolated hepatocytes.

Reverse tri-iodothyronine (3,3',5'-tri-iodothyronine, rT3), a major product of the peripheral monodeiodination of thyroxine, was administered subcutaneously to fed rats at a dose of 100 micrograms/100 g body weight for 2 consecutive days. This dose induced a 17-fold increase in plasma rT3 (from 0.05 +/- SEM 0.01 to 0.85 +/- 0.11 ng/ml, P less than 0.001) whilst the plasma T3 concentration was decreased to half of the control value (0.40 +/- 0.03 to 0.20 +/- 0.02 ng/ml, P less than 0.01). As a result of these changes the T3/rT3 ratio was therefore decreased from 8.0 +/- 1.6 to 0.23 +/- 0.03 (P less than 0.001). Hepatocytes prepared from control or rT3-treated rats were incubated with [1-14C]oleate and the rates of 14CO2 release and glucose production were estimated. Despite the changes in ratio of T3 to rT3 observed in vivo, rates of 14CO2 release and glucose production rate from hepatocytes subsequently isolated were unchanged.

Animals↗
PubMed1980

Man in space.

Explore the source record for details and available documents.

Aerospace Medicine↗
PubMed1980

A study of partial thiamin restriction in human volunteers.

A double blind study of partial thiamin restriction was undertaken in 19 volunteer male medical students for a period of 4 to 5 weeks. Each day the subjects followed a diet supplying 500 micrograms thiamin and took 1 capsule randomly assigned to contain 5 mg thiamin hydrochloride or thiamin placebo. This capsule also supplied physiological doses of other vitamins. At the end of the study all were repleted with thiamin hydrochloride. Ten thiamin-depleted subjects were correctly identified by low urinary thiamin excretion, decreasing erythrocyte transketolase activity, and elevation of the thiamin pyrophosphate effect. The remaining nine subjects were controls. The degree of thiamin depletion induced varied between individuals and had no measurable ill effect on health as assessed by subjective feelings, physical findings, psychological testing, nerve conduction studies, and work performance. Subclinical thiamin deficiency is defined from this study as the presence of a low urinary thiamin level (27 microgram thiamin/g creatinine) together with a thiamin pyrophosphate effect above 14.2% and below 35.4%. However, when urinary thiamin excretion is unknown, the data indicate that a thiamin pyrophosphate effect above 9% and below 41.6% is likely but not certain to represent subclinical thiamin deficiency. These guidelines, developed under experimental conditions, are a reference framework for assessment of thiamin status in population groups but should be applied with caution to individuals and to people with disease.

Adolescent↗
PubMed1977

The effect of frusemide used for post-prostatectomy irrigation on total body potassium.

The effects of 2 techniques of bladder irrigation on total body potassium have been compared. The results show that a net decrease was associated with both methods. This was marginally greater (0.1 greater than P greater than 0.05) in the group which underwent a forced diuresis using frusemide with a fluid load. This group received some potassium supplements without which it is possible that the decrease would have been greater. It is concluded that this regime cannot be overtly criticised for its potential loss of potassium.

Aged↗
PubMed1977

The effect of surgical operation on venous plasma free amino acids.

The effects of abdominal operation on the antecubital vein plasma amino acid concentration were examined. With four groups, each containing ten patients, factors such as severity of surgical operation, anesthesia, and postoperative nutrition were examined. Immediately after operation there is a fall in the plasma concentrations of most amino acids; the nonessential amino acids (glutamate, proline, glycine, alanine, histidine, and arginine) continue to fall during the 2 postoperative days, whereas the essential amino acids (isoleucine, leucine, phenylalanine, and lysine, with tyrosine) are at higher concentration at 48 hours than immediately after operation. Comparison of a group of patients undergoing an operation of moderate severity (vagotomy and pyloroplasty or cholecystectomy) with those having the more severe procedure of resection of aortic aneurysm with Dacron graft replacement suggests that these general changes in amino acid concentrations do not appear to be due to the severity of the operation, although cystine levels were lower, and phenylalanine levels were higher, in the graft-replacement group. The changes did not appear to be the result of anesthesia. Increasing the postoperative glucose intake was associated with higher plasma alanine and lower methionine levels. It is suggested that, in surgical patients, cystine and tyrosine may become essential amino acids and rises in phenylalanine and methionine indicate transient liver dysfunction. The data give support to the view that a high calorie intake after operation has a beneficial effect.

Abdomen↗