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Biomedical subjects

R M Gray

Publications and source records attributed to R M Gray.

At least 19 recordsLinked to original sources
PubMed2001

Orthodontics and occlusion.

The discipline of orthodontics is directed towards alteration of the occlusion of the teeth and the relationships of the jaws. It is therefore somewhat surprising to find that there is little scientific evidence to support any of the concepts that suggest occlusal goals for orthodontic treatment. Most of the current concepts of orthodontic treatment are based upon personal opinion and retrospective studies. Nevertheless, an attempt is made here to provide a guide to the relationship of orthodontics and the occlusion that is evidence based. Where the evidence is weak, these areas have been highlighted.

Centric Relation↗
PubMed2001

Good occlusal practice in removable prosthodontics.

The loss of teeth may result in patients experiencing problems of a functional, aesthetic and psychological nature. This section addresses the very important subject of occlusal considerations for partial and complete dentures. The occlusion is particularly important given the bearing that occlusal factors have, especially on edentulous patients.

Alveolar Process↗
PubMed2001

Good occlusal practice in advanced restorative dentistry.

In most patients the existing occlusal scheme will be functional, comfortable and cosmetic; and so if a tooth or teeth need to be restored, the most appropriate way to provide the restoration(s) would be to adopt a 'conformative' approach: that is to provide treatment within the existing envelope of static and dynamic occlusal relationships. There will, however, be situations where the conformative approach cannot be adopted, and this section aims to describe what is 'Good Occlusal Practice' in these circumstances.

Centric Relation↗
PubMed2001

Good occlusal practice in simple restorative dentistry.

Many theories and philosophies of occlusion have been developed. 1-12 The difficulty in scientifically validating the various approaches to providing an occlusion is that an 'occlusion' can only be judged against the reaction it may or may not produce in a tissue system (eg dental, alveolar, periodontal or articulatory). Because of this, the various theories and philosophies are essentially untested and so lack the scientific validity necessary to make them 'rules'. Often authors will present their own firmly held opinions as 'rules'. This does not mean that these approaches are to be ignored; they are, after all, the distillation of the clinical experience of many different operators over many years. But they are empirical. In developing these guidelines the authors have unashamedly drawn on this body of perceived wisdom, but we would also like to involve and challenge the reader by asking basic questions, and by applying a common sense approach to a subject that can be submerged under a sea of dictate and dogma.

Dental Occlusion↗
PubMed2001

The examination and recording of the occlusion: why and how.

Before presenting 'how' the examination and recording of the occlusion may be achieved, some attempt should be made to justify 'why' it is necessary. It may appear to be a strange way of justifying the need to examine the patient's occlusion, but this will initially involve a study of the influences of mandibular movements.

Centric Relation↗
PubMed2001

What is occlusion?

The aim of this series of papers is to explore the role of occlusion in dental practice. The range of opinion in the dental profession as to the importance of occlusion is enormous. It is very important that the profession in general and practising dentists in particular have a balanced view of occlusion. This is more important than every patient having a balanced occlusion. The fact that the study of occlusion is characterised by extremes makes it confusing and possibly difficult for individual dentists to find a philosophy which is in line with contemporary good practice supported by evidence from practice-based research.

Bite Force↗
PubMed2001

Construct validity of Wechsler factor scores.

The construct validity of the Verbal Comprehension. Perceptual Organization, and Freedom from Distractibility factor scores was examined in a sample of school-aged referred children. Examination of correlations between factor scores and neuropsychological and achievement tests generally supported the construct validity of the factors. The Verbal Comprehension factor was associated with verbal, quantitative, and concept-formation abilities. The Perceptual Organization factor was related to nonverbal concept formation, tactual performance, and visual attention. The Freedom from Distractibility factor demonstrated a complex pattern of correlations and appeared to reflect a range of abilities including quantitative, language, attentional, and concept formation.

Adolescent↗
PubMed2000

Patterns of academic achievement among patients treated early with phenylketonuria.

UNLABELLED: This paper provides a review of recent studies investigating the academic achievement of patients treated for phenylketonuria. These studies consistently indicate that these patients demonstrate mild academic difficulties, primarily with mathematics but with reading and spelling skills as well. In addition to the review of previous studies, academic achievement results are presented for a sample of 32 school-age, early-treated patients with phenylketonuria. CONCLUSION: Consistent with previous studies, results from the current study suggest that patients in this sample demonstrate mild difficulties with basic spelling and basic mathematical calculation skills.

Achievement↗
PubMed2000

Factor structure of the Reitan-Indiana Neuropsychological Battery for Children.

The Reitan-Indiana Neuropsychological Battery (RINB) was administered to a sample of children referred for educational and behavioral problems (N = 130). Subtest scores were standardized by age at 1-year intervals (6, 7, and 8 years). A principal components analysis (PCA) with promax rotation of 18 subtest scores produced a five-factor solution. Factor 1 emphasizes tactile/spatial functions, Factor 2 emphasizes concept formation and visual/spatial abilities, Factor 3 reflects motor strength, Factor 4 emphasizes sensory perception, and Factor 5 reflects motor speed. Principal factor analysis (PFA) of these data was performed to permit comparison with the PCA solutions. The PFA and PCA solutions were similar and major conclusions about factor structure were consistent.

Child↗
PubMed2000

Reference group data for the Reitan-Indiana Neuropsychological Test Battery for Young Children.

This study presents a data set for a reference group on the Reitan-Indiana Neuropsychological Test Battery for Young Children. The data set is based on a sample of 224 children, ages 5 to 8 years, referred to a special services cooperative for academic or behavioral concerns during the years 1980 through 1993. Data are presented in terms of sample size, means, standard deviations, diagnostic classifications, and population characteristics. Previously published data sets are reviewed in comparison to this newly acquired data set. Potential advantages of this data set include the larger sample, contemporary data collection, and a sample drawn from a United States school-referred population.

Child↗
PubMed1999

Internal consistency of three tests from the Halstead-Reitan neuropsychological battery for older children.

The internal consistency of three neuropsychological tests was examined in a sample of 334 referred children (9-14 years of age). Coefficient alpha was calculated to estimate reliability on the Seashore Rhythm Test (SRT), two forms of the Speech Sounds Perception Test (SSPT), and the Aphasia Screening Test (AST). The standard SSPT appears to have relatively good internal consistency with an average coefficient of.81. The average coefficient for the abbreviated form of the SSPT was considerably lower (i.e.,.73), highlighting the superiority of the standard form in clinical practice. Internal consistency of the SRT was relatively low (i.e.,. 67). This level of reliability may be acceptable in group research and for component tests, but is marginal for independent clinical use. Coefficient alpha for the AST was moderate (i.e.,.77), suggesting adequate reliability for a screening test. These reliability estimates are compared to those obtained in previous studies using these tests in adult samples and with other tests commonly used with children.

Adolescent↗
PubMed1998

Effects of fish oil supplementation on apolipoprotein B100 production and lipoprotein metabolism in normolipidaemic males.

OBJECTIVE: To evaluate the effects of four weeks of fish oil supplementation on apolipoprotein B100 production and lipoprotein metabolism in normolipidaemic males. DESIGN AND SUBJECTS: Very low density lipoprotein (VLDL) apolipoprotein B100 (apoB100) kinetics in ten healthy, white males, aged 22-43 y (mean 32 y) were investigated using 13C-leucine technique and gas chromatography-mass spectrometry before and after fish oil supplementation. INTERVENTION: All subjects received 10 g (1.8 g EPA, 1.2 g DHA)/d of fish oil concentrate for four weeks. RESULTS: Fish oil supplementation resulted in a decrease of total plasma VLDL (mean +/- s.d. 1.11 +/- 0.41 vs 0.87 +/- 0.28 mmol/l, P < 0.05) and triacylglycerol concentrations (0.74 +/- 0.27) vs 0.48 +/- 0.21 mmol/l, P < 0.01). VLDL apoB100 pool size was decreased without alteration of the fractional synthetic rate but a significant decrease of apoB100 production (2.23 +/- 0.90 vs 1.54 +/- 0.52 mg/dl/h, P < 0.02). Following fish oil supplementation plasma concentrations of glucose and insulin as well as lipoprotein and hepatic lipase activities were unchanged. Fasting plasma concentrations of non-esterified fatty acid (NEFA) were decreased (0.45 +/- 0.12 vs 0.33 +/- 0.10 mmol/l, P < 0.05). CONCLUSIONS: Dietary supplementation with fish oil in healthy males results in decreased VLDL-triacylglycerol concentrations through a decrease in VLDL particle synthesis. The decrease in NEFA substrate supply also contributes.

Adult↗
PubMed1996

Use of the long vs short form of the speech sounds perception test in a school-age population.

A sample of 645 school-age children, ages 9 to 14 years, were administered independent forms of the Speech Sounds Perception Test for older children. 328 subjects took the complete test (SSPT-60) and 317 were administered only the first 30 items (SSPT-30). Comparison of mean errors indicated that significantly more errors were made by subjects given the SSPT-30. Decisions regarding the use of each form for school-age children are discussed.

Affective Symptoms↗
PubMed1996

Factor analysis of the Intermediate Category Test.

This study examined the factor structure of the six subtests of the Intermediate Category Test in a heterogeneous sample of school-referred students, age 9 to 14 years. A three-factor solution emerged that accounted for approximately 72% of the total variance. This indicates that the test measures multiple underlying constructs in this school-referred sample. Clinical and educational interpretations may be enhanced by utilizing factor scores that reflect the multiple abilities assessed. Recommendations for developing factor/index scores are provided.

Adolescent↗
PubMed1994

Thoracic CT images: effect of lossy image compression on diagnostic accuracy.

PURPOSE: To evaluate the effects of lossy image (noninvertible) compression on diagnostic accuracy of thoracic computed tomographic images. MATERIALS AND METHODS: Sixty images from patients with mediastinal adenopathy and pulmonary nodules were compressed to six different levels with tree-structured vector quantization. Three radiologists then used the original and compressed images for diagnosis. Unlike many previous receiver operating characteristic-based studies that used confidence rankings and binary detection tasks, this study examined the sensitivity and predictive value positive scores from nonbinary detection tasks. RESULTS: At the 5% significance level, there was no statistically significant difference in diagnostic accuracy of image assessment at compression rates of up to 9:1. CONCLUSION: The techniques presented for evaluation of image quality do not depend on the specific compression algorithm and provide a useful approach to evaluation of the benefits of any lossy image processing technique.

Humans↗
PubMed1994

Complications of flexor tendon injuries.

Despite the many advances in the surgical and rehabilitative management of flexor tendon injuries, problems of adhesion, contracture, and rupture continue to limit the restoration of function in a significant number of cases. This article reviews the most frequent complications after flexor tendon injuries. The treatment options for these problems, including the authors' methods of choice, are discussed.

Adult↗