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G T Smith

Publications and source records attributed to G T Smith.

At least 73 records · Page 4Linked to original sources
PubMed1995

Assessment of skeletal muscle viability by PET.

UNLABELLED: We investigated the use of [18F]fluoro-2-deoxyglucose (FDG) PET scanning for assessment of skeletal muscle viability in patients with peripheral vascular disease and in patients following free-flap skeletal muscle transfer for closure of open wounds. METHODS: We obtained 32 FDG-PET scans from 30 patients, either at the time of admission for peripheral vascular disease (n = 16) or between 1 and 15 days after surgery for skeletal muscle transfer (n = 16). Ratios between injured and contralateral limb FDG tracer activity uptake were correlated with clinical outcome at 1 mo to 3 yr follow-up. RESULTS: Viable muscle uptake ratios ranged from 0.47 to 7.88 (mean: 2.26 +/- 1.81; n = 26), while nonviable muscle uptake ratios ranged from 0.12 to 0.46 (mean: 0.27 +/- 0.12; n = 6; p < 0.02). After skeletal muscle transfer, two patients with viable tissue, as documented by PET, required amputation due to osteomyelitis, and one patient with peripheral vascular disease who showed viable tissue by PET required amputation 3 mo after the PET scan because of recurrent ulcers. CONCLUSION: FDG-PET scanning can determine skeletal muscle viability in patients with peripheral vascular disease and in patients following free-flap transfer.

Adolescent↗
PubMed1994

Psychological expectancy as mediator of vulnerability to alcoholism.

Alcohol expectancy has proven to be a powerful predictor of drinking behavior, including alcoholism, in a wide range of groups. Three recent studies that begin to address expectancy's relation to other alcoholism vulnerability factors are reviewed. Results indicate that: (1) expectancies for reinforcement from alcohol predate teens' first drinking experiences; (2) expectancies predict subsequent drinking onset and problem drinking; (3) high initial expectancies lead to a vicious cycle of progressively more drinking and more positive expectancies during the adolescent years; (4) expectancy mediates the influence of family drinking history on adolescent drinking; and (5) as an alcohol-specific risk factor, expectancy adds to and (in women) interacts with more general, dispositional (personality) risk factors to predict problem drinking in young adults. These findings support the model of expectancy as a mediator of the original causal influences of earlier learning experiences.

Adolescent↗
PubMed1994

Formulating clinical research hypotheses as structural equation models: a conceptual overview.

Structural equation modeling is a comprehensive, flexible approach to research design and data analysis. Although in recent years there has been phenomenal growth in the literature on technical aspects of structural equation modeling, relatively little attention has been devoted to conceiving research hypotheses as structural equation models. The aim of this article is to provide a conceptual overview of clinical research hypotheses that invite evaluation as structural equation models. Particular attention is devoted to hypotheses that are not adequately evaluated using traditional statistical models.

Humans↗
PubMed1994

Substance use disorder: abuse, dependence and dyscontrol.

The purpose of this paper is to review the diagnostic concepts of substance abuse and substance dependence provided in DMS-III, DSM-III-R, and the forthcoming DSM-IV. The review incorporates the principles that there are no infallible criteria for identifying when a person lacks sufficient control over the usage of a drug, that dyscontrol exists on a continuum, that substance use dyscontrol shares many formal properties with behavioral dyscontrol within other domains, and that the diagnosis of a mental disorder should be free of moralistic connotations. We conclude the paper with an alternative proposal, wherein the DSM-IV diagnoses of abuse and dependence are collapsed within one diagnosis of substance dyscontrol disorder and physiological substance dependence is placed with the diagnoses of substance intoxication and substance withdrawal.

Comorbidity↗
PubMed1994

Modifying alcohol-related expectancies in grade-school children.

Expectancies for reinforcement from alcohol appear to form during the grade-school years and play a causal role in problem drinking behavior. Using a sample of 268 second through fourth graders, we investigated whether children's expectancies could be modified successfully. Children were randomly assigned to one of four conditions: two experimental expectancy modification conditions (using 10-minute video interventions), one control condition involving a 10-minute video presenting facts concerning alcohol's deleterious effects, and one no-intervention control condition. Relative to controls, expectancies were increased by one experimental condition and decreased by the other; these changes were sustained at 4-week follow-up. This suggests expectancy modification should be tested as an adjunct to current prevention programs. Relations of gender and family history of problem drinking or alcoholism to expectancy endorsement are described.

Alcohol Drinking↗
PubMed1993

Assessment of primary and metastatic ovarian cancer by positron emission tomography (PET) using 2-[18F]deoxyglucose (2-[18F]FDG).

The potential of positron emission tomography (PET) to distinguish benign from malignant ovarian tissue was evaluated by comparing the results of F-18 fluoro-2-D-deoxyglucose (F-18-FDG) PET scans with computed tomography and surgical findings. If sufficiently sensitive, this method might play a role in localizing metabolically active tumor sites for diagnosis, staging, and follow-up of ovarian cancer. Fifty-one patients had imaging studies prior to laparotomy for suspected ovarian cancer. PET scans were done with an ECAT 931-08-12 or ECAT EXACT (Model 921, Siemens/CTI, Knoxville, TN) after iv injection of 185-370 MBq of F-18-FDG. (ECAT is a trade name for "emission computerized axial tomograph.") Data were acquired in dynamic scanning mode and time activity curves (TACs) were evaluated in multiple regions of interest identified by visual interpretation of the PET scans. Scan interpretation, standardized uptake values, and TAC profiles were related to surgical and histological findings. The results of this pilot study show good correlation between PET and histological findings. The positive predictive value of PET for ovarian cancer was 86% and, perhaps more important, the negative predictive value was 76%. This early work indicates that PET may be useful in the management of patients with ovarian neoplasms by identifying occult foci of metabolically active tumor that do not appear on morphological studies.

Adolescent↗
PubMed1993

Open evaluation of a new non-preserved artificial tear.

In an open, one-eye controlled study the efficacy of a new, non-preserved artificial tear (sodium chloride 0.34% W/W, hydroxyethylcellulose 0.44% W/W), stored in single-use disposable units (Minims, Smith and Nephew) was compared to a variety of other tear substitutes in 30 patients who were currently applying artificial tears to both eyes. It was found that the new drop was tolerated well by the majority of patients with 19 subjects (63%) preferring them to their existing medication. There was a significant reduction in the overall rose bengal staining pattern and also in the stain uptake of the medial conjunctiva between the first and second visits in the Minims treated eyes, but not in the eyes treated with the other drops (P < 0.05). There was also a significant improvement in the patients' subjective feelings of dryness and grittiness in the Minims treated eyes, but not in the other eyes (P < 0.05).

Adult↗
PubMed1992

Accuracy of self-reported weight: covariation with binger or restrainer status and eating disorder symptomatology.

Studies indicate that women's self-reported and actual weights correlate above .90 but that approximately one-third of women under-report their weight by more than 5 lb. Overweight women under-report to a greater degree than women of normal weight. The present study replicated these findings and extended them to women showing eating disorder-related behaviors, including regular binging and dietary restraint. Reporting accuracy was also covaried with eating disorder tendencies as measured on a continuum in the general population. Despite high statistical power, results revealed no correlation between under-reporting and either Bulimia Test scores or Eating Attitudes Test scores and found no differences in reporting accuracy as a function of binger status or restrained eater status. Women manifesting eating disorder-relating behaviors were neither more nor less accurate than were normals. Potential sources of error in measuring weight and in evaluating self-report are presented and discussed.

Adult↗
PubMed1992

Changes in light scatter and width measurements from the human lens cortex with age.

Light scatter and width measurements of the anterior cortical layers of the human lens were made in 50 eyes of 50 subjects using computerised linear scanning densitometry of Scheimpflug images. It was demonstrated that the amount of light scatter increased with age in all of the three major zones and that zone C3 showed the most marked increase. Most lens growth occurs in zone C2 with C3 showing little increase in width once it has become established. Zone C1 showed a tendency to decrease in width with age. In addition it was shown that the C3 zone, which is not present at birth and during early childhood, appears as a distinct layer during the second decade of life. Its scattering properties continue to increase throughout life, exceeding all other zones after approximately 30 years of age, in the absence of cataract. Possible explanations for the lens zone pattern are discussed.

Adolescent↗
PubMed1992

Effects of timolol ophthalmic solution on the intra-ocular pressure rise induced by suxamethonium and tracheal intubation.

Thirty patients received topical application of either timolol ophthalmic solution 0.25%, or normal saline, 2 h before elective ophthalmic surgery in a double-blind study. The responses to suxamethonium and tracheal intubation were compared by measuring intra-ocular pressure before induction of anaesthesia, 1 min after administration of thiopentone 2-4 mg.kg-1, 1 min after administration of suxamethonium 1 mg.kg-1, and 1, 2.5 and 5 min after tracheal intubation. There was no significant difference between the groups.

Adult↗
PubMed1992

Capsular 'pits' in the human lens.

The lens capsule is an atypical basement membrane surrounding the lens epithelial cells and lens fibres which make up the remainder of the human lens. A seemingly unreported morphological change visible in the lens capsule with the biomicroscope is described.

Coronary Disease↗
PubMed1991

Alcoholism and memory: broadening the scope of alcohol-expectancy research.

Current biopsychosocial research on the etiology of alcoholism has begun to focus on memory processes as a possible common pathway for drinking decisions. The alcohol-expectancy construct is rooted both in cognitive psychology and alcohol research and can serve as a vehicle for this study. Reexamination of one recent review of issues in alcohol-expectancy research provides an opportunity to broaden the scope of this research with theoretical and methodological alternatives to those suggested in that review. Most importantly, this article shows that expectancy findings, discussed by Leigh (1989a) as reflecting "psychometric" limitations, are instead quite consistent with recent network models of memory structure. Such models can provide an informative guide to future research activities. It is also recommended that alcohol-expectancy research remain open to inputs from expectancy theories already developed in several psychological domains, as well as to theories of social cognition and attitude structure in addition to those advanced by Leigh.

Alcohol Drinking↗
PubMed1991

Inter and intra observer reproducibility of the new Oxford CCD Scheimpflug camera.

Scheimpflug photography is a well recognised technique for obtaining sagittal views of the anterior structures of the human eye in vivo. A new generation of Scheimpflug camera, which uses a CCD (charge coupled device) instead of film, permitting the digitised image achieved to be directly analysed using computerised linear scanning densitometry, is described. The advantages and present limitations of this system over the older film using system are discussed and the reproducibility of the new CCD system in its ability to measure certain features of the crystalline lens is presented.

Anthropometry↗
PubMed1990

The economics of hypertension and stroke.

The prevention of stroke through the control of hypertension is cost-effective economically and medically. A reduced incidence of stroke generates savings to the health service in hospital and surgical costs, and the avoidance of premature mortality means survivors contribute more to the economy as a result of extra working years. In addition to financial benefits, antihypertensive agents can also improve a patient's quality of life. This can be measured with a variety of health profiles or indexes and is often expressed together with life expectancy in quality-adjusted life years. This article examines the benefits produced by the effective control of hypertension, taking data from England and Wales during the past 30 years.

Cerebrovascular Disorders↗
PubMed1990

Refractive changes in silicone filled eyes.

In this study we examined refractive changes of 34 eyes in 34 patients treated with silicone oil injection. Six patients presented with aphakic retinal detachment, another 14 were rendered aphakic after silicone oil injection, one was pseudophakic and 13 were still phakic at the time of writing this report. Silicone oil in the vitreous cavity induced a myopic shift in aphakic eyes and a hypermetropic shift in phakic eyes. This tended to render phakic high myopes and aphakes closer to emmetropia. The resultant refraction was dependent on the shape of the silicone oil bubble inside the eye and influenced by the posture of the patient. In phakic patients the ability to accommodate was markedly reduced.

Accommodation, Ocular↗
PubMed1990

Light scatter from the central human cornea.

Light scatter from the central human cornea was measured in 60 eyes of 60 patients using computerised image analysis of Scheimpflug slit image photographs. There was no correlation between the amount of scatter and the age of the patients (correlation 0.035, p = 0.79). In addition it was found that light was scattered more at the anterior and at the posterior surfaces of the cornea than from the stroma.

Adolescent↗