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Biomedical subjects

S Myerson

Publications and source records attributed to S Myerson.

15 recordsLinked to original sources
PubMed2002

Automatic MRI adipose tissue mapping using overlapping mosaics.

This paper presents an automatic method of correcting non-uniform RF coil response for the classification of body composition using MR imaging. By linear mosaic modelling, the smoothly but non-linearly varying bias field, which modulates tissue intensities within the image, was corrected. The overlapping between adjacent mosaics ensured consistent segmentation of body fat content and the effectiveness of the technique was validated by both phantom and in vivo experiments. Ten whole body composition data sets, each with 39 trans-axial slices, were acquired. Automatic segmentation results using the proposed technique were compared with those from manual delineations. The automatic segmentation method was found to be highly accurate and the mean percentage error between the two methods was less than 1.5%.

Adipose Tissue↗
PubMed2001

Bradykinin B2BKR receptor polymorphism and left-ventricular growth response.

Angiotensin-converting-enzyme (ACE) activity regulates left-ventricular growth. The deletion (D), rather than the insertion (I), ACE gene variant is associated with increased ACE activity and kinin degradation, and the absence (-) rather than the presence (+) of a 9 bp deletion in the gene encoding the bradykinin 2 receptor (B2BKR) is associated with greater gene expression. We determined the ACE and B2BKR genotype of 109 male army recruits, and measured their physiological left-ventricular growth response to a 10-week physical training programme. Mean left-ventricular growth was 15.7 g (SE 3.5) in those with ACE genotype D/D and B2BKR genotype +9/+9, but -1.37 g (4.1) in those with ACE genotype I/I and B2BKR genotype -9/-9 (p=0.003 for trend across genotypes). These results suggest that kinins regulate left-ventricular growth, mediating some of the effects of ACE in this regard.

Adult↗
PubMed2000

Angiotensin-converting enzyme genotype affects the response of human skeletal muscle to functional overload.

The response to strength training varies widely between individuals and is considerably influenced by genetic variables, which until now, have remained unidentified. The deletion (D), rather than the insertion (I), variant of the human angiotensin-converting enzyme (ACE) genotype is an important factor in the hypertrophic response of cardiac muscle to exercise and could also be involved in skeletal muscle hypertrophy - an important factor in the response to functional overload. Subjects were 33 healthy male volunteers with no experience of strength training. We examined the effect of ACE genotype upon changes in strength of quadriceps muscles in response to 9 weeks of specific strength training (isometric or dynamic). There was a significant interaction between ACE genotype and isometric training with greater strength gains shown by subjects with the D allele (mean +/- S.E.M.: II, 9.0+/-1.7 %; ID, 17.6 +/-2.2 %; DD, 14.9+/-1.3 %, ANOVA, P 0.05). A consistent genotype and training interaction (ID DD II) was observed across all of the strength measures, and both types of training. ACE genotype is the first genetic factor to be identified in the response of skeletal muscle to strength training. The association of the ACE I/D polymorphism with the responses of cardiac and skeletal muscle to functional overload indicates that they may share a common mechanism. These findings suggest a novel mechanism, involving the renin-angiotensin system, in the response of skeletal muscle to functional overload and may have implications for the management of conditions such as muscle wasting disorders, prolonged bed rest, ageing and rehabilitation, where muscle weakness may limit function.

Adolescent↗
PubMed1999

Human angiotensin I-converting enzyme gene and endurance performance.

Human physical performance is strongly influenced by genetic factors. A variation in the structure of the human angiotensin I-converting enzyme (ACE) gene has been reported in which the insertion (I) variant is associated with lower ACE levels than the deletion (D) gene. We have previously reported that the I variant was associated with improved endurance performance in high-altitude mountaineers and British Army recruits. We now examine this genotype distribution in 91 British Olympic-standard runners (79 Caucasians). DNA was extracted from the buccal cells contained in 10 ml of saline mouthwash donated by the subjects, and the I and D variants of the ACE gene were identified by PCR amplification of the polymorphic region. There was an increasing frequency of the I allele with distance run [0.35, 0.53, and 0.62 for </=200 m (n = 20), 400-3,000 m (n = 37), and >/=5,000 m (n = 34), respectively; P = 0.009 for linear trend]. Among 404 Olympic-standard athletes from 19 other mixed sporting disciplines (in which endurance performance was not necessarily a key factor), the I allele did not differ significantly from that found in control subjects: 0.50 vs. 0.49 (P = 0.526). These results support a positive association of the I allele with elite endurance performance.

Alleles↗
PubMed1997

Seven women GPs' perceptions of their stresses and the impact of these on their private and professional lives.

Explores the stresses of seven women GPs and the impact of these on their work and home life. It is a qualitative study which uses a free flowing interview approach. The aim is to reflect the perceptions of these women GPs rather than the assumptions of the researcher. It is an in-depth investigation which gives some insights into the lives of these women doctors working as general practitioners. It adds to the knowledge and understanding of the stresses of GPs in general and women GPs in particular.

Adaptation, Psychological↗
PubMed1995

Narrative in research: the research and the researcher survey--women GPs and stress.

Activities and stresses are linked and can be viewed closely only as a sequence of actors and behaviors, or a narrative. Examines such narratives from the which the individualized stress emerges plainly. Emphasizes that the researcher is involved in a narrative of her own life and reactions to the research project. Portrays the interdependence of these narratives: those of the doctor or GP under survey and those of the researcher.

England↗
PubMed1993

Improving the response rates in primary care research. Some methods used in a survey on stress in general practice since the new contract (1990).

This paper describes some methods used to improve the response rates in a survey on "stress in general practice since the new contract", and it discusses some of the literature on this problem. The methodology is a detailed account of steps taken to improve the presentation to the general practitioner (GP) in the letter, the forms and postal procedures that accompany the questionnaire, so as to focus the doctor's attention. The changes made in the reminder attempts are explained and the results noted. It is argued that it is important to attempt to improve rates to make the survey as meaningful as possible. These methods may be of particular use in primary care research.

Adult↗
PubMed1991

Violence to general practitioners and fear of violence.

This paper describes the perception of general practitioners of violence to which they are subject, and also their fears of violence. It is based on interviews, and a written questionnaire. The outcome suggests that violence is a formidable problem. Some coping strategies are described. On the whole the subject has been little ventilated, but its recognition is an urgent matter.

Adaptation, Psychological↗
PubMed1990

Investigating stresses in general practice using an open-ended approach in interviews.

This paper describes a preliminary study which investigated the stresses of 30 general practitioners in London. The methodology used was an unstructured interview technique known as 'emic'. This aimed to obtain the doctors' own perceptions of their stresses. The accounts were therefore 'free-flowing'. The links between this 'open-ended' methodology and the findings are discussed. In this kind of approach stresses are uncovered--produced by the subject--which would otherwise not be revealed to the investigator. Once established, stresses which surface in this way, can be considered in a more structured setting later. Furthermore, this 'open-ended' interview produces a 'story', a collection of narrative fragments which together provide a unique record of a field of human experience.

Aged↗