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Biomedical subjects

G Smith

Publications and source records attributed to G Smith.

At least 775 records · Page 43Linked to original sources
PubMed1983

Amitriptyline disposition in young and elderly normal men.

The disposition of a single parenteral or single oral dose of amitriptyline was followed in seven young (mean age 22 yr, range 21 to 23) and five elderly (mean age 71 yr, range 62 to 81) healthy men. The mean systemic clearance did not change with age (10.8 +/- 2.1 ml/min/kg in elderly and 12.5 +/- 2.3 ml/min/kg in young subjects). Mean t 1/2 was longer in the older (21.7 +/- 2.9 hr) than in the younger group (16.2 +/- 6.1 hr) as a result of an increase in the volume of distribution (17.1 +/- 2.4 and 14.1 +/- 2.0 l/kg). The bioavailability and the fraction of the drug bound to plasma proteins did not change with age. Single doses of amitriptyline were not well tolerated clinically by either elderly or young subjects, which confirms the need for a gradual buildup in the therapeutic regimen and for close clinical surveillance of elderly depressed patients treated with amitriptyline.

Administration, Oral↗
PubMed1983

Catecholamine responses during anaesthesia for phaeochromocytoma.

Plasma catecholamine concentrations were measured, at frequent intervals, in a 40-yr-old female patient undergoing resection of a phaeochromocytoma under enflurane anaesthesia. Measurements before operation revealed that the tumour secreted predominantly noradrenaline and during surgery the plasma concentration of the hormone increased markedly (180 pmol ml-1; normal range 1.5-3.0 pmol ml-1). Plasma adrenaline concentrations increased markedly only at endotracheal intubation and in the period immediately after operation.

Adrenal Gland Neoplasms↗
PubMed1983

Plasma catecholamine responses to tracheal intubation.

Plasma adrenaline and noradrenaline concentrations were measured in 24 patients during the induction of anaesthesia and the subsequent tracheal intubation. The patients received either suxamethonium 1 mg kg-1 or pancuronium 0.1 mg kg-1 to facilitate tracheal intubation. Mean arterial pressure (MAP) increased in both groups following laryngoscopy and tracheal intubation and there were concomitant increases in the plasma catecholamine concentrations, the changes being more marked in the suxamethonium group. There was a significant correlation between MAP and plasma catecholamine concentrations in the suxamethonium group. Measurement of plasma catecholamine concentrations in samples obtained simultaneously from central venous, peripheral venous and arterial sites were in broad agreement; the greatest changes occurred in central venous samples.

Aged↗
PubMed1983

Construction, specification, and mathematical description of aspheric surfaces.

Rotationally symmetrical aspheric surfaces of spectacle lenses are constructed as either "zonal aspherics" or "continuous aspherics." Zonal aspherics consist of annular zones surrounding a central zone with each zone being nominally spherical with progressively lower surface power the farther the zone is from the surface vertex. Aspheric surfaces are often specified by the radial drop in surface power from the center to the edge of the lens (e.g., Welsh Four-drop), but for assessment purposes the surface shape must be specified more precisely. The formulas for the description of continuous aspherics can be manipulated into different forms. Mathematical descriptions are given or developed which will enable theoretical assessment of the performances of all lenses with rotationally symmetrical aspheric surfaces.

Eyeglasses↗
PubMed1983

Laboratory evaluation of commercial aspheric aphakic lenses.

Four types of commercial aspheric aphakic lenses were assessed with respect to mass, spectacle magnification, off-axis power errors, and peripheral distortion. The aspheric lenses have better distortion and off-axis imagery properties than spherical flat back lenses, but the improvement in distortion properties is small for those lenses whose design form specifies a flattish back surface. The claims concerning the distortion properties of these lenses are exaggerated. The shape (bending) of lenses has a large effect on spectacle magnification, peripheral distortion, and off-axis imagery.

Aphakia, Postcataract↗
PubMed1983

Menstrual cycle variations of corneal topography and thickness.

Two studies were performed to investigate dimensional stability of the cornea throughout the female menstrual cycle. In the first study, changes of corneal curvature, topography, and thickness were measured for six women for one complete menstrual cycle. Steepening of horizontal and vertical curvatures occurred at the beginning of the cycle, and flattening occurred after ovulation. Corneal thickening occurred on the second day of the cycle and around the time of ovulation, then thinning and another slight thickening on day 21. In the second study, more detailed information was sought on the timing of corneal thickness changes throughout any cycle. Corneal thickness was studied for two subjects throughout three consecutive cycles. Both subjects showed a slight decrease in thickness toward the end of the menses; thickening occurred at ovulation followed by thinning. Thickening also occurred 4 days after ovulation. Consideration of changes in urine levels of estrogen and pregnanediol suggests that rises in estrogen are accompanied by increases in corneal thickness.

Adult↗
PubMed1983

Aspheric high positive power lenses and third order theory.

To correct third order (primary) oblique astigmatism of thin spectacle lenses outside an approximate lens power range of -22 D to +7 D, one surface must be aspherized. Aspherizing is of particular importance in the high positive power range used for the correction of aphakia. Graphs are presented showing the required front surface asphericities and power drops required to correct oblique astigmatism in this range. The results are a guide to the required asphericities in thick lenses.

Astigmatism↗
PubMed1983

Prognostic significance of biopsy results of normal-looking mucosa in cases of superficial bladder cancer.

Quadrant biopsies of normal-looking mucosa were used as part of the assessment of cases with superficial Ta,T1 transitional cell cancer of the bladder. Patients with one or more abnormal biopsies were shown to have a significantly greater chance of developing recurrent tumour compared to patients with normal mucosal biopsy findings. Other factors noted at the time of initial assessment, such as size, number of tumours, Ta,T1 category or grade of tumour did not predict recurrence, although recurrences that invaded muscle were associated with G3 histology in the primary tumour. The results of mucosal biopsy identified patients at risk for recurrence and it is possible that this group would derive particular benefit from adjuvant chemotherapy.

Carcinoma, Transitional Cell↗
PubMed1983

Selection of an obstetric data base for a microcomputer and its use for on-line production of birth notification forms, discharge summaries and perinatal audit.

A microcomputer system is described which stores data for perinatal audit and produces 'on-line' the statutory birth notification form and mother and baby discharge summary. The derivation of a minimum data-base and the methods used to obtain reliable data are outlined. The results of a trial of the production of the birth notification form for 195 deliveries are reported together with those of a further trial of 86 deliveries in which the system was used to produce both the notification form and the discharge summary. A study of the accuracy of the handwritten birth notification forms revealed a high error rate which was markedly reduced by the use of the microcomputer system. The system is now in routine use and further developments are outlined.

Computers↗
PubMed1983

Incidence of delayed stress disorder among Vietnam era veterans: the effect of priming on response set.

Recent studies concluded that a significant number of Vietnam era veterans suffer now from a service-related stress disorder. This paper suggests that a priming artifact may have operated in many such studies to confound an understanding of the nature and estimate of the disorder. Findings of a study designed to test the effect of priming on veterans' self-ratings support the hypothesis that veterans, particularly noncombat veterans, tend to rate themselves in a manner consistent with prior information provided by the testers.

Adult↗
PubMed1983

Lymphangioma of kidney.

Lymphangioma of kidney is a rare, symptomatic but benign tumour. A case is reported and the literature reviewed. Aetiology and its effect on the incidence, non-invasive investigation, treatment and pathology are discussed.

Aged↗
PubMed1983

Effect of conicoid asphericity on the Tscherning ellipses of ophthalmic spectacle lenses.

One of the criteria in ophthalmic spectacle lens design is the elimination of oblique astigmatism. For a range of equivalent powers, Seidel (primary or third-order) astigmatism can be eliminated, and the solutions of back- (or front-) surface power are commonly displayed graphically in the form of ellipses (Tscherning ellipses). The Tscherning ellipses apply only to lenses constructed from spherical surfaces. If one or both surfaces are made aspheric, the solutions for zero astigmatism are no longer in the form of ellipses. If one surface, usually the front surface, is made as a conicoid aspheric, the solutions for zero astigmatism can be presented graphically similarly to the Tscherning ellipses. For any given equivalent power, there are two or no solutions for spherical lenses. However, there is always one and up to three solutions for conicoid aspheric lenses.

Eyeglasses↗
PubMed1983

Numbers of word associations to color patches and color names differ across two opponent pairs.

68 female undergraduate students completed word-association and semantic-differential tasks in response to stimuli which were patches or names of eight colors. The number of word associations for the group viewing color patches differed from that of the group responding to color names on the basis of four colors forming two of the three opponent pairs of the opponent-process theory of color vision.

Adult↗
PubMed1983

The susceptibility of BALB/C and other inbred mouse strains to Brugia pahangi.

The susceptibility of several strains of inbred mice to infection with the filarial worm Brugia pahangi has been examined. BALB/C, C57BL/10, C3H/He, 101, CBA/Ca mice, congenitally asplenic (DH/+) mice and their normal litter-mates (+/+) were each challenged by the intraperitoneal inoculation of 50 infective larvae. During the first four weeks of infection high (19-42%) larval recoveries were obtained from the CBA/Ca, BALB/C and Dh/+ mice but fewer than 10% of inoculated larvae were recovered from C3H/He, 101; C57BL/10 and +/+ mice. Larval growth rates in all mice were similar. BALB/C and Dh/+ mice only were examined later than four weeks after infection. The yield of adult worms from BALB/C was 7.5% at 16 weeks and from Dh/+ 4.2% at 21 weeks. Microfilariae were present in the peritoneal fluids but not the blood of some mice harbouring both adult male and female worms.

Animals↗