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Biomedical subjects

R Matthews

Publications and source records attributed to R Matthews.

At least 19 recordsLinked to original sources
PubMed2006

Cancer incidence among semiconductor and electronic storage device workers.

AIMS: To evaluate cancer incidence among workers at two facilities in the USA that made semiconductors and electronic storage devices. METHODS: 89 054 men and women employed by International Business Machines (IBM) were included in the study. We compared employees' incidence rates with general population rates and examined incidence patterns by facility, duration of employment, time since first employment, manufacturing era, potential for exposure to workplace environments other than offices and work activity. RESULTS: For employees at the semiconductor manufacturing facility, the standardised incidence ratio (SIR) for all cancers combined was 81 (1541 observed cases, 95% confidence interval (CI) 77 to 85) and for those at the storage device manufacturing facility the SIR was 87 (1319 observed cases, 95% CI 82 to 92). The subgroups of employees with > or =15 years since hiring and > or =5 years worked had 6-16% fewer total incidents than expected. SIRs were increased for several cancers in certain employee subgroups, but analyses of incidence patterns by potential exposure and by years spent and time since starting in specific work activities did not clearly indicate that the excesses were due to occupational exposure. CONCLUSIONS: This study did not provide strong or consistent evidence of causal associations with employment factors. Data on employees with long potential induction time and many years worked were limited. Further follow-up will allow a more informative analysis of cancer incidence that might be plausibly related to workplace exposures in the cohort.

Adult↗
PubMed2006

Development and testing of a questionnaire to measure patient satisfaction with intermediate care.

BACKGROUND: Individual trials have suggested high levels of general patient satisfaction with intermediate care, but this topic has not been examined in detail. AIMS: To identify the key elements of patient satisfaction with intermediate care, and to see whether these can be validly measured using a questionnaire. METHOD: A questionnaire was developed on the basis of a literature review and piloting with patients and staff on participating schemes (phase I). In phase II, the questionnaire was tested for validity and reliability in a group of patients recently discharged from two "hospital-at-home" intermediate-care schemes. In phase III, a shortened version of the questionnaire was psychometrically tested in five sites taking part in a national evaluation of intermediate care. RESULTS: 96 patients with an average age of 76.5 years took part in phase II. Test-retest reliability was evaluated by repeating the questionnaire 2 weeks later in a subsample of 42 patients. This was "moderate" (kappa 0.4-0.6) for 12 questions, "fair" (kappa 0.2-0.4) for 6 questions and "poor" (kappa 0.1-0.2) for 5 questions. Scores correlated well with the Client Satisfaction Questionnaire (Spearman's r = 0.75, p<0.001). 843 patients (57% of those eligible) from five intermediate-care schemes took part in phase III. Principal components analysis suggested six factors or subscales: general satisfaction, affective response, cognitive response, timing of discharge, coordination after discharge, and access to pain relief, although the last three factors comprised only one question each. The intraclass correlation coefficients in the first three subscales varied from 0.82 to 0.89. Scores for all subscales differed by scheme, suggesting construct validity. Only one question (on general satisfaction) was found to be redundant. CONCLUSION: The questionnaire, with some minor amendments to improve performance, could be used as a validated tool for audit and research in intermediate care. An amended version and scoring programme is available from us on request.

Aged↗
PubMed2005

The political ecology of health: perceptions of environment, economy, health and well-being among 'Namgis First Nation.

Informed by Mayer's (Progr. Hum. Geogr 20 (1996) 441) political ecology of disease framework, this paper investigates First Nation's perceptions of the links between environment, economy and health and well-being. A case study of 'Namgis First Nation (Alert Bay, British Columbia, Canada) is used to explore the risks and benefits of salmon aquaculture for British Columbia's First Nations. Analysis of interview data (n = 23) indicates strong links between reduced access to environmental resources, marginal participation in the economy, and declining community health and well being. Results suggest that aquaculture development has further decreased the community's access to environmental resources, thereby restricting those economic, social, and cultural activities that determine good health and well-being for this community.

Animals↗
PubMed2005

An updated study of mortality among North American synthetic rubber industry workers.

AIM: This study evaluated the mortality experience of workers from the styrene-butadiene industry. METHODS: The authors added seven years of follow up to a previous investigation of mortality among 17 924 men employed in the North American synthetic rubber industry. Analyses used the standardised mortality ratios (SMRs) to compare styrene-butadiene rubber workers' cause specific mortality (1943-98) with those of the United States and the Ontario general populations. RESULTS: Overall, the observed/expected numbers of deaths were 6237/7242 for all causes (SMR = 86, 95% CI 84 to 88) and 1608/1741 for all cancers combined (SMR = 92, 95% CI 88 to 97), 71/61 for leukaemia, 53/53 for non-Hodgkin's lymphoma, and 26/27 for multiple myeloma. The 16% leukaemia increase was concentrated in hourly paid subjects with 20-29 years since hire and 10 or more years of employment in the industry (19/7.4, SMR = 258, 95% CI 156 to 403) and in subjects employed in polymerisation (18/8.8, SMR = 204, 95% CI 121 to 322), maintenance labour (15/7.4, SMR = 326, 95% CI 178 to 456), and laboratory operations (14/4.3, SMR = 326, 95% CI 178-546). CONCLUSION: The study found that some subgroups of synthetic rubber workers had an excess of mortality from leukaemia that was not limited to a particular form of leukaemia. Uncertainty remains about the specific agent(s) that might be responsible for the observed excesses and about the role of unidentified confounding factors. The study did not find any clear relation between employment in the industry and other forms of lymphohaematopoietic cancer. Some subgroups of subjects had more than expected deaths from colorectal and prostate cancers. These increases did not appear to be related to occupational exposure in the industry.

Aged↗
PubMed2004

Capitation plans.

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Capitation Fee↗
PubMed2004

Activation of waste MDF sawdust charcoal and its reactive dye adsorption characteristics.

This paper reports an experimental investigation of converting waste medium density fibreboard (MDF) sawdust into chars and activated carbon using chemical activation and thermal carbonisation processes. The MDF sawdust generated during the production of architectural mouldings was characterised and found to have unique properties in terms of fine particle size and high particle density. It also has a high content of urea formaldehyde resin used as a binder in the manufacturing of MDF board. Direct thermal carbonisation and chemical activation of the sawdust by metal impregnation and acid (phosphoric acid) treatment prior to pyrolysis treatment were carried out. The surface morphology of the raw dust, its chars and activated carbon were examined using scanning electron microscopy (SEM). Adsorptive properties and total pore volume of the materials were also analysed using the BET nitrogen adsorption method. Liquid adsorption of a reactive dye (Levafix Brilliant red E-4BA) by the derived sawdust carbon was investigated in batch isothermal adsorption process and the results compared to adsorption on to a commercial activated carbon (Filtrasorb F400). The MDF sawdust carbon exhibited in general a very low adsorption capacity towards the reactive dye, and physical characterisation of the carbon revealed that the conventional chemical activation and thermal carbonisation process were ineffective in developing a microporous structure in the dust particles. The small size of the powdery dust, the high particle density, and the presence of the urea formaldehyde resin all contributed to the difficulty of developing a proper porous structure during the thermal and chemical activation process. Finally, activation of the dust material in a consolidated form (cylindrical pellet) only achieved very limited improvement in the dye adsorption capacity. This original study, reporting some unexpected outcomes, may serve as a stepping-stone for future investigations of recycle and reuse of the waste MDF sawdust which is becoming an increasing environmental and cost liability.

Adsorption↗
PubMed2004

Diet as a risk factor for the development of stress urinary incontinence: a longitudinal study in women.

OBJECTIVE: To assess the association between diet and the onset of stress urinary incontinence (SUI) in women aged 40 y plus. DESIGN AND SETTING: The Leicestershire MRC Incontinence Study - a prospective longitudinal study of the prevalence, incidence and aetiology of urinary symptoms. SUBJECTS AND METHODS: A total of 5816 women aged 40 y plus and living in the community. Urinary symptoms were reported in a postal questionnaire at baseline and at 1-y follow-up. Dietary intake was assessed in a food frequency questionnaire at baseline. RESULTS: Intakes of total fat, saturated fatty acids and monounsaturated fatty acids were associated with an increased risk of SUI onset 1 y later. Of the micronutrients studied, zinc and vitamin B12 were positively associated with SUI onset. CONCLUSION: The results from this prospective study suggest there may be an aetiological association between certain components of the diet and the onset of SUI. The findings need confirming and possible mechanisms to explain these associations need further investigation.

Adult↗
PubMed2003

Evaluation of an oral health scoring system by dentists in general dental practice.

UNLABELLED: An Oral Health Index (OHX) has been designed to provide a numerical measure of the overall state of a patient's oral health by means of a series of simple clinical examinations. This has been amended to produce the Oral Health Score (OHS). OBJECTIVE: To assess, by means of a questionnaire, the ease of use and understanding of the OHS by general dental practitioners. METHODS: 350 GDPs were asked to participate in the project, of whom 329 agreed. These dentists were given a lecture of 2 hours' duration on the OHS. The participating dentists were requested to use the OHS for a period of 1 year. At the end of this period, a questionnaire was delivered to them by post, with an explanatory letter and reply-paid envelope. RESULTS: Completed, usable questionnaires were received from 239 GDPs, a 77% response rate. Ninety three percent of respondents considered the OHS instructions to be satisfactory. The respondents' views on the criteria on which the OHS component assessments are based indicated that over 90% of respondents agreed with the criteria for caries, adequacy of restorations, periodontal assessment, mucosal assessment and assessment of dentures. A majority of respondents agreed that the OHS provided a valid representation of oral health. CONCLUSION: The results of the present study indicate that the OHS is considered to be an easy-to-use measure of a patient's oral health and that it provides a valid representation of a patient's oral health.

Dental Health Surveys↗
PubMed2002

Accidental implantation of a bur tip in the elbow of a dentist. A possible pathway for inoculation with deadly infectious agent.

The most common source of occupational injury to dentists is percutaneous puncture of the hands from "sharps". We report a percutaneous injury involving a dentist where the tip of a dental bur became implanted in his elbow. The dentist had been vaccinated against Hepatitis B and both the patient and dentist were Hiv and Hepatitis B seronegative immediately after the incident. Surgical exploration of the dentist's elbow the following day was unsuccessful in locating the bur tip. The dentist remains healthy and is not incapacitated as a result of the injury, despite retention of the bur tip. This accident has implications for modifying the design of present and future dental units. We are not aware of a previous report of this type of injury.

Accidents, Occupational↗
PubMed2001

Effect of neurophilin ligands on motor units in mice with SOD1 ALS mutations.

BACKGROUND: Mice with trangenes that express mutations in the gene for cytosolic copper/zinc superoxide dismutase (SOD1) develop motor neuron degeneration resembling human ALS. Neurophilin ligands are small molecules that promote neurite outgrowth. OBJECTIVE: To test the hypothesis that treatment with two neurophilin ligands increases survival in these ALS mice by slowing the loss of motor neurons and increasing the sizes of motor units. METHODS: Transgenic mice hemizygous for the G93A mutation were untreated or treated from 30 days of age with one of two doses of two neurophilin ligands (V-13,670; V-10,367, Vertex Pharmaceuticals, Boston, MA). Onset of behavioral abnormalities and survival were recorded. Motor unit number estimation (MUNE) was performed every 21 days starting at age 60 days. RESULTS: In control animals, disease onset occurred at 77.0 days of age and death occurred at 137 days of age. Neither neurophilin ligand affected the disease course. In control animals, MUNE declined with time beginning before behavioral abnormalities were noted, and motor unit size increased concomitantly. There was no effect of drug on motor unit loss as assessed by MUNE; however, motor unit size increased more rapidly and to a greater degree in animals treated with V-13,670. CONCLUSION: As in human ALS, the transgenic ALS mice show physiologic changes in the motor unit prior to the development of clinical signs: MUNE declines as motor unit size increases. Although neither neurophilin ligand significantly affected survival, one produced an increase in motor unit size. The fact that survival was not altered by the increase in motor unit size may reflect the rapid disease course in this animal model.

Amyotrophic Lateral Sclerosis↗
PubMed2001

Minimal data sets.

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Data Collection↗
PubMed2001

Leukemia and exposure to 1,3-butadiene, styrene and dimethyldithiocarbamate among workers in the synthetic rubber industry.

This study evaluated relations between exposure to 1,3-butadiene (BD), styrene (STY) and dimethyldithiocarbamate (DMDTC) and mortality from leukemia among synthetic rubber industry workers. Subjects were 13130 men employed for at least 1 year during 1943-1991 at any of six plants that manufactured synthetic rubber. Death certificates and medical records identified workers with leukemia. Cumulative exposure estimates were based on plant- and time period-specific process and task characteristics, linked to subjects' work histories. Poisson regression estimated relative rates (RRs) for workers exposed to each agent compared to unexposed workers. Leukemia (N=59) was positively associated with BD ppm-years (RRs of 1.0, 1.2, 2.0 and 3.8, for exposures of 0, >0-<86.3, 86.3-<362.2 and 362.2+ ppm-years; only the RR for the highest exposure category was statistically significant), STY ppm-years (RRs of 1.0, 1.2, 2.3 and 3.2, for exposures of 0, >0-<20.6, 20.6-<60.4 and 60.4+ ppm-years; only the RR for the highest exposure category was statistically significant) and DMDTC mg-years/cm (RRs of 1.0, 2.3, 4.9 and 2.9, for 0, >0-<566.6, 566.6-<1395.1 and 1395.1+ mg-years/cm; the RR for each non-zero exposure category was statistically significant) after adjusting for age and years since hire. After further adjusting each agent-specific set of RRs for the other two agents, a positive but imprecise relation remained for BD and DMDTC but not for STY. The association with BD was stronger for ppm-years due to exposure intensities >100 ppm than for ppm-years due to lower concentrations. BD and DMDTC, but not STY, were positively associated with leukemia in multivariable analyses. The independent effect of each agent was difficult to evaluate because of correlations with other agents and imprecision.

Butadienes↗
PubMed2001

An epidemiological study of tori among 667 dental outpatients in Trinidad & Tobago, West Indies.

AIM: To study the prevalence of tori amongst dental outpatients, the ethnic and sex variations in their distribution, and their clinical features. SETTING: The School of Dentistry, St. Augustine, Trinidad & Tobago. PARTICIPANTS: 667 consecutive dental outpatients representing three different ethnic groups of the country. METHODS: Clinical examination for and recording of tori indicating their location, extent and clinical features and the age, sex and ethnic grouping of the patient. RESULTS: The overall prevalence of tori was 12.3 per cent. CONCLUSIONS: There were no significant differences in the prevalence among the African, Indian or mixed ethnic groups of patients examined. There seemed to be strong link between the coexistence of palatal and mandibular tori.

Adolescent↗
PubMed2001

Metastasis of breast carcinoma to mandibular gingiva.

Metastatic tumours to the oral region are rare but more often involve the jaws rather than the oral soft tissues. In this report, an infiltrative ductal carcinoma of the breast that metastasised to the mandibular gingiva is presented. The patient consulted her dentist for what she thought was a dental abscess in the bicuspid region of the lower left jaw. However, her dentist referred her for a specialist opinion of the lesion. The patient's medical history revealed that she had undergone a breast 'lumpectomy' 1 year previously. A provisional diagnosis of primary or metastatic malignancy was made, and a biopsy was performed. Microscopically, the lesion showed features of a poorly differentiated infiltrative ductal carcinoma. Subsequent microscopic review of the primary lesion also showed a poorly differentiated infiltrating ductal carcinoma of the breast identical to the features observed in the metastatic lesion.

Biopsy↗
PubMed2001

Facial swelling and gingival enlargement in a patient with sickle cell disease.

Sickle cell anemia is a frequent hemoglobinopathy in the Caribbean. While vaso-occlusion induced tissue injury in sickle cell anemia is common in various organs, orofacial lesions are rare. A 14-year-old Afro-Trinidadian boy suffering from sickle cell anemia developed an acute facial swelling, mimicking facial cellulitis of dental origin, which was caused by sickle cell-related hemorrhage. He also exhibited gingival enlargement, considered to be an outcome of repeated hemorrhagic episodes and fibrous repair. A new finding is the presence of erythrocyte-filled intraepithelial blood vessels in the gingival epithelium. We hypothesize this phenomena is a tissue response to hypoxia that occurs in sickle cell disease.

Acute Disease↗
PubMed2001

A pilot randomized clinical trial on the relative effect of instrumental (MFMA) versus manual (HVLA) manipulation in the treatment of cervical spine dysfunction.

OBJECTIVE: To determine the relative effect of instrument-delivered thrust cervical manipulations in comparison with traditional manual-delivered thrust cervical manipulations in the treatment of cervical spine dysfunction. DESIGN: Prospective, randomized, comparative clinical trial. SETTING: Outpatient chiropractic clinic, Technikon Natal, South Africa. PATIENTS: Thirty patients diagnosed with neck pain and restricted cervical spine range of motion without complicating pathosis for at least 1 month were included in the study. INTERVENTIONS: The patients were randomized into 2 groups. Those in one group received mechanical force, manually assisted (MFMA) manipulation to the cervical spine, delivered by means of a hand-held instrument (Activator II Adjusting Instrument). Those in the other group received specific contact high-velocity, low-amplitude (HVLA) manipulation consisting of standard Diversified rotary/lateral break techniques to the cervical spine. Each group received only the specific therapeutic intervention, no other treatment modalities or interventions (including medication) being used, until asymptomatic status was achieved or a maximum of 8 treatments had been received. MAIN OUTCOME MEASURES: Both treatment groups were assessed through use of subjective (Numerical Pain Rating Scale 101, McGill Short-Form Pain Questionnaire, and Neck Disability Index) and objective (goniometer cervical range of motion) measurement parameters at specific intervals during the treatment period and at 1-month follow-up. The data were assessed through use of 2-tailed nonparametric paired and unpaired analysis, descriptive statistics, and power analysis of the data. RESULTS: The results indicate that both treatment methods had a positive effect on the subjective and objective clinical outcome measures, no significant difference being observed between the 2 groups (P < .025). The subjective data from all 3 questionnaires showed statistically significant changes from initial to final consultations as well as from initial consultation to 1-month follow-up (P < .025). The objective range of motion measures showed statistically significant changes in the MFMA group for left and right rotation and left and right lateral flexion from initial consultation to final consultations and for right rotation and right lateral flexion from initial consultation to 1-month follow-up. The HVLA group showed only the change in left rotation from initial to final consultations and from initial consultation to 1-month follow-up to be statistically significant. CONCLUSIONS: The results of this clinical trial indicate that both instrumental (MFMA) manipulation and manual (HVLA) manipulation have beneficial effects associated with reducing pain and disability and improving cervical range of motion in this patient population. A randomized, controlled clinical trial in a similar patient base with a larger sample size is necessary to verify the clinical relevance of these findings.

Adult↗