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Biomedical subjects

R I Evans

Publications and source records attributed to R I Evans.

At least 19 recordsLinked to original sources
PubMed1998

The effect of growth temperature on the phospholipid and fatty acyl compositions of non-proteolytic Clostridium botulinum.

A non-proteolytic strain of Clostridium botulinum (NCIB 4270) was found to have a complex lipid composition, comprising five major phosphorus-containing lipids: phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylserine (PS) and a glycophospholipid of unknown structure (GPL), in order of abundance. Changing the growth temperature did not alter the lipid composition either qualitatively or quantitatively. The main fatty acyl components of the lipids are 14:0, 16:0 and 16:1. When the growth temperature was lowered from 37 to 8 degrees C, there was an increase in 14:0 from 16.4 to 37.5%, an increase in 16:1 from 10.5 to 22.5%, and a decrease in the proportion of 16:0 from 40.3 to 19.1%. There was also a decrease in the proportion of cyclopropane fatty acids (15:0cyc and 17:0cyc) from 7.3 to 0.5%, and in the equivalent chain length of the total fatty acids from 15.9 to 15.3 as the temperature was lowered. The same temperature-dependent changes occurred in the five major lipid classes examined. Despite reports of the presence of plasmalogenic forms of phospholipids (i.e. those lipids which have the acyl chain in the sn-1 position replaced by an alk-1-enyl group) in some Clostridium spp., none were detected in C. botulinum NCIB 4270 using either commercially available spray reagents or by gas-liquid chromatographic analysis of the products or acid methanolysis of total lipid extracts. It is concluded that non-proteolytic C. botulinum lacks plasmalogens, typical of other clostridia, in its membranes and instead modulates its fatty acid composition in response to temperature changes in a manner that is typical of other (non-clostridial) bacteria.

Chromatography, Gas↗
PubMed1998

Survey of injuries among West End performers.

OBJECTIVES: To obtain more information about injuries of West End performers. METHODS: A retrospective survey of 269 performers appearing in 20 West End productions (12 dramas and eight musicals). RESULTS: In current productions, 46% of all performers sustained at least one injury for an average of 0.87 injuries per performer. Lower extremity injuries were the most common for dancers (52.2% of injuries) and actors (43.2%) with neck and back injuries the second most common. Sprains and strains were the most common diagnoses. 61% of performers thought that their injuries were preventable. Most performers consulted nonphysician healthcare providers. Factors significantly influencing the risk of injuries for performers include female sex, a history of previous injuries, missed performances due to previous injuries, more physically demanding roles, and performing on raked (angled) stages. CONCLUSION: West End performers commonly sustain injuries. Although primary prevention of most theatrical injuries is not possible, modification of raked stages may reduce the incidence. This study may be helpful to the growing number of healthcare providers who practice performing arts medicine and may stimulate additional concern and research in the medical and theatrical communities about the performance injuries of professionals, amateurs, and theatrical students worldwide.

Accidents, Occupational↗
PubMed1997

The germinability of spores of a psychrotolerant, non-proteolytic strain of Clostridium botulinum is influenced by their formation and storage temperature.

The formation and storage temperatures of Clostridium botulinum spores are shown to influence their subsequent ability to germinate. Spores were formed at 10 degrees, 20 degrees, 30 degrees and 37 degrees C and following harvest were stored as aqueous suspensions at 20 degrees C (ambient temperature), 4 degrees C (refrigerated) or -20 degrees C (frozen) for periods of up to 1 month. The spores formed at 20 degrees C germinated most rapidly and to the greatest extent. When the spores were germinated immediately after harvest (fresh), there was no difference in the germinability of those spores formed at 20 degrees or 30 degrees C, whether or not they had been heat-shocked before use. However, following storage overnight or longer, differences in the relative germinabilities of the different spore samples were seen. Spores which had been stored at ambient temperature overnight germinated significantly faster and to a greater extent than did those which had been stored for up to 1 month. Similar differences were also observed between spores germinated fresh and those stored overnight, when the spores were stored refrigerated or frozen. Germinability was also influenced by the temperature of storage, since there were differences between spores formed at the same temperature but stored at different temperatures for the same period of time: for example, when spores which had been formed at 20 degrees C were germinated at 10 degrees C following a heat-shock, those which had been stored at ambient temperature germinated faster and to a greater extent than did those which had been stored refrigerated or frozen. It is concluded that there is a complex interaction between formation, storage and germination temperatures, which determines spore germinability. The fact that the changes are time-dependent and can occur in the frozen state is taken to mean that they are physico-chemical rather than metabolic. It is also significant in relation to refrigerated foods which are at risk from Cl. botulinum in that changes which occur during cool or frozen storage can enhance the germinability of spores if the temperature rises above that of chill cabinets.

Clostridium botulinum↗
PubMed1996

Craniotomy guidance using a stereo-video-based tracking system.

In open intracranial neurosurgery, it is desirable to minimize exposure and to approach the target in the most accurate way possible. The VISLAN system described here employs a completely passive hand-held locator which is tracked by a video system and does not require a mechanical linkage nor cables. The system also tracks easily recognizable, constant, anatomical landmarks of the patient. By this means the initial registration of pre-operative imaging and the detection of, and correction for, patient movement can be accomplished. High-resolution MRI segmented interactively is used to define external surface and brain anatomy. Thus, a pre-operative patient representation (POPR) is planned. During the surgical procedure the patient's head is illuminated by structured light and stereo-video pictures obtained from two television cameras mounted above the head. The system is calibrated and registered with the POPR using a chamfered matching algorithm. The locator is also tracked in space by the video system, and its tip position shown in relation to the POPR on the video monitor.

Craniotomy↗
PubMed1996

A survey of injuries among Broadway performers.

To obtain more information about injuries of Broadway performers, 313 performers appearing in 23 Broadway companies were surveyed. The percentage of performers injured was 55.5%, with a mean of 1.08 injuries performer. Lower extremity injuries were the most common. Sixty-two percent of performers believed that their injuries were preventable. As this study reports factors that significantly increase the risk of injury for dancers and actors, it may help to heighten concern with reducing the incidence of injuries to professional performers, theatrical students, and nonprofessionals worldwide.

Accidents, Occupational↗
PubMed1994

Intraclass correlation among common measures of adolescent smoking: estimates, correlates, and applications in smoking prevention studies.

Most adolescent smoking prevention studies employ designs in which classrooms, schools, school districts, or sometimes whole communities are assigned to treatment conditions while observations are made on individual students. The critical design feature in such community trials is the nesting of intact social groups within treatment conditions. This combination requires that the treatment effect be assessed against the between-group variance; unfortunately, that variance is usually larger than for randomly constituted groups and its precision is usually less than that for the within-group variance. These factors often combine to reduce power so that it is almost impossible to detect important treatment effects in an otherwise well designed and properly executed study. To address these problems, investigators need good estimates of the intraclass correlation for the variables of interest, which together with the number of observations per unit determine the magnitude of the extra variation in the nested design. The purpose of this paper is to describe the methods and results from a study designed to generate estimates of intraclass correlation for common outcomes in adolescent smoking prevention studies and to discuss the use of these estimates in the planning of new studies.

Adolescent↗
PubMed1994

The physician survey on the post-concussion and whiplash syndromes.

BACKGROUND: The post-concussion syndrome (PCS) and whiplash syndrome (WS) have been controversial topics among physicians for many decades. There is little information available on the opinions and practices of physicians. METHODS: In June of 1992, we performed a national survey by mail of the four physician groups most commonly treating these problems. The number of respondents and response rates were as follows: family physicians, 118, 16%; neurologists, 100, 21%; neurosurgeons, 97, 23%; orthopedists, 82, 13%. The survey instrument contained items on demographics, definitions, causation, prognosis, medico-legal aspects, testing, and treatment. RESULTS: Only a minority of respondents believe that PCS and WS are clearly defined syndromes. A substantial minority report that psychogenic and litigation factors are most responsible for the conditions. Most of the physicians believe that PCS and WS have a 3-6 month recovery time. A significant minority concur that symptoms of the two syndromes resolve when litigation is settled. Most of the physicians order tests to rule out pathology although a minority order tests to reassure patients or because of litigation concerns. Only a minority of respondents believe that effective treatments are available. Not surprisingly, a multitude of conventional and unconventional treatments are sometimes recommended. CONCLUSIONS: Many aspects of PCS and WS are controversial among treating physicians. This controversy can have a profound impact on the quality and cost of patient care. Ongoing research is required to discover more effective treatments for mild brain injury and chronic pain.

Brain Concussion↗
PubMed1992

Diagnostic accuracy and observer performance in the diagnosis of abnormalities in the anterior maxilla: a comparison of panoramic with intraoral radiography.

An investigation was undertaken to assess the reliability of radiographic diagnosis of abnormalities of orthodontic significance in the anterior region of the maxilla from intraoral and dental panoramic tomograph (DPT) views. DPT films of 200 patients were scrutinised by two observers on two separate occasions, who also examined intraoral radiographs of the same patients. Sixty-three of these patients were selected because they had previously been diagnosed as presenting with a defined abnormality of orthodontic relevance, such as supernumerary teeth, absent incisors, etc. The remaining cases had been assessed as depicting normal radiographic appearances. Each radiograph was allocated a unique, randomly selected code number as the only means of identification. It was not possible for the observers to match the DPT to the corresponding intraoral films, and this information was only available to the principal investigator (JWF). Both observers were asked to record the presence or otherwise of any abnormalities at each observation of each radiograph, and to record their findings. The overall level of diagnostic accuracy and reproducibility was fairly high, and in general terms the DPT views were as reliable as the intraoral films with regard to the detection of abnormalities; however, there were significant differences between the observers. It was concluded that in many instances supplementary intraoral films would not contribute any additional information compared to the DPT and that selection criteria should be defined for the former.

Chi-Square Distribution↗
PubMed1991

Quality assurance. A project on patient waiting times at appointment in an orthodontic department.

A quality assurance project to establish patient waiting time at appointments was undertaken over a four-week period during the spring of 1989. The Orthodontic Department was selected as one of two departments in the Birmingham General Hospital/Birmingham Dental Hospital unit site that was to participate in the programme initiated at the District Health Authority management level. Patient waiting periods for a total of 142 clinical sessions were assessed. Fifty per cent of patients were kept waiting and 50 per cent were seen either earlier or at their appointed time. The mean period of time that patients were kept waiting past their appointment time was 9.4 min (+/- 10.9). On clinics for which patients arrived late the mean time that they were kept waiting increased to a mean of 18.9 min (+/- 9.1). Data from 92 patient questionnaires established that they considered a reasonable mean time of waiting to be 16.1 min (+/- 7.9). Five recommendations were proposed as a result of this quality assurance initiative and their implementation is discussed.

Appointments and Schedules↗
PubMed1989

Formative evaluation in school-based health promotion investigations.

This article is intended for behavioral and biomedical researchers who have become involved increasingly in health promotion research in social settings. It describes how researchers may more precisely plan and profit from employing formative evaluation, which is too frequently more casually undertaken than is summative evaluation. Formative evaluation includes responses from the student subjects of such programs and school administrative and instructional staff, as well as other elements unique to the school setting such as existing curricula and the logistics of time and space. In order to tailor such programs to the unique properties of the school setting, a continual feedback loop should be in place. Such loops can channel both quantitative and qualitative data to the researcher to assist in adapting projects to changing conditions during the course of their implementation. This article presents a case history of the application of formative evaluation drawn from a health promotion project conducted by the authors. It includes as background for this case history, definitions of formative evaluation and an analysis of its costs.

Adolescent↗
PubMed1989

Smoking.

Explore the source record for details and available documents.

Forecasting↗
PubMed1989

Effect of initial treatment of chronic inflammatory periodontal disease in adults on spontaneous peripheral blood lymphocyte proliferation.

The spontaneous proliferative response (SPR) of peripheral blood lymphocytes, as a measure of the autologous mixed lymphocyte reaction (AMLR), has been found to be depressed in adults with chronic inflammatory periodontal disease (CIPD). The aim of the present study was to test the hypothesis that initial treatment of CIPD in adults restores the SPR to normal levels. 10 periodontal disease subjects (mean probing attachment loss of 4.2 mm and a mean bleeding index of 0.65) and 10 age- and sex-matched healthy control subjects were studied. The SPR for each patient was evaluated on days 3, 5, 7, 9 and 11 in culture, before and after initial treatment for CIPD. The peak SPR, which occurred at day 5, was depressed in the untreated periodontal disease subjects compared to the healthy control subjects (p less than 0.01). In addition, the kinetics of the SPR were found to be significantly different in 4 of the 10 parameters compared with the untreated periodontal disease patients and the healthy control subjects. After treatment, there was a significant reduction in probing attachment loss and bleeding indexes (p less than 0.001). In addition, the magnitude of the peak SPR was not significantly different from that of the healthy control subjects. Nevertheless, a difference in 1 of the 10 kinetic parameters persisted, which suggested that complete restoration of the SPR to normal had not occurred so soon after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Progressive development of supernumerary teeth in cleidocranial dysplasia.

A 9-year-old boy suffering from cleidocranial dysplasia presented with multiple unerupted permanent teeth and five unerupted supernumerary teeth. During a 4-year observation and treatment period he developed nine more supernumerary teeth at a time when normally new teeth would no longer be forming. By the age of 13 years and 5 months a total of fourteen supernumerary teeth had been produced and it is possible that more teeth may develop in the future.

Adolescent↗
PubMed1989

The evolution of challenges to researchers in health psychology.

One of the keynote addresses presented at the National Working Conference on Research in Health and Behavior. This address is a historical review of current challenges to researchers in health psychology. Current challenges discussed include (a) creation of physical pathology, (b) physical symptoms of physical pathology in the absence of true pathology, (c) increased or decreased vulnerability to infectious disease, (d) intensify, prolong, or diminish existing pathology, (e) individuals' preoccupation with illness or disease, (f) voluntarily engaging in health-threatening behavior (e.g., allowing toxic agents to enter the body or engaging in accident-prone behavior or high-risk sexual practices), (g) engaging in health-enhancing life-style behaviors, and (h) involuntarily becoming the victim of toxic agents. The shift in public health policy as related to psychological research--from mental health to physical illness--reflects societal support for such areas of research by health psychologists.

Cognition↗
PubMed1989

Smoking research: basic research, intervention, prevention, and new trends.

Smoking is a behavior that is influenced by a variety of factors that cut across methodologies, disciplines, and content areas within health psychology. The present article is designed to show the diversity and richness of smoking research by examining smoking from four perspective: basic laboratory research, intervention, prevention and deterrence, and new directions in smoking research. Methodologies that were derived from such varied sources as psychopharmacology, behavioral pharmacology, behavior therapy, clinical psychology, public health and health promotion, and social and developmental psychology have been used to study the smoking problem. The subject populations in these investigations ranged from animal models, to the individual smoker attempting to quit, to communities involved in health promotion and public health approaches. Future research should seek to provide new and improved examples of interdisciplinary research within the field of health psychology to multidisciplinary approaches from the basic and applied sciences.

Humans↗
PubMed1988

Health promotion--science or ideology?

This article is the author's American Psychological Association Division 38 Presidential Address, which was delivered at the 1987 APA meetings. It challenges health psychologists to be wary of becoming zealots in health promotion activities without continuing to recognize that health promotion programs should be anchored in sound science. This is discussed in terms of the biomedical research support for a recommended health practice or in terms of the psycho-socio-behavioral research support for techniques applied or advocated in intervention programs. To illustrate this problem in health promotion, the research foundations for recommendations of cholesterol control programs and the "Say No to Drugs" campaigns are explored. Other concerns relating to the appropriate role for the health psychologist in health promotion activities are also discussed.

Health Promotion↗