Physiological and immunocytochemical evidence that glutamatergic neurotransmission is involved in the activation of arm autotomy in the featherstar Antedon mediterranea (Echinodermata: Crinoidea).

The crinoid echinoderm Antedon mediterranea autotomises its arms at specialised skeletal joints known as syzygies that occur at regular intervals along the length of each arm. Detachment is achieved through the nervously mediated destabilisation of ligament fibres at a particular syzygy. The aim of this investigation was to identify neurotransmitters that are involved in the autotomy response. Physiological experiments were conducted on isolated preparations of syzygial joints, which can be induced to undergo autotomy-like fracture by applying stimulatory agents such as elevated [K(+)](o). Initial experiments with elevated [K(+)](o) showed that the autotomy threshold (the minimum amount of stimulation required to provoke autotomy) is lowest in syzygies at the arm base and rises distally. Of a range of neurotransmitter agonists tested, only l-glutamate invoked syzygial destabilisation, as did its analogues l-aspartate, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and kainate, but not l-(+)-2-amino-4-phosphonobutyrate (l-AP4) or N-methyl-d-aspartate (NMDA). The implication that l-glutamate stimulates syzygial fracture through AMPA/kainate-like receptors was supported by the finding that the action of l-glutamate was inhibited by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Acetylcholine depressed the response of syzygial preparations to l-glutamate, suggesting a possible mechanism by which the autotomy threshold could be varied constitutively and facultatively. An immunocytochemical method employing a polyclonal antibody against l-glutamate conjugated to glutaraldehyde revealed l-glutamate-like immunoreactivity in all components of the putative neural pathway controlling the autotomy reflex, including the epidermis, brachial nerve, syzygial nerves and cellular elements close to the syzygial ligaments. We conclude that it is highly probable that l-glutamate acts as an excitatory neurotransmitter in the activation of arm autotomy in A. mediterranea.

Interprofessional attitudes and perceptions: Results from a longitudinal controlled trial of pre-registration health and social care students in Scotland.

This study made use of a controlled longitudinal design to assess the impact on pre-registration health and social care students of an interprofessional intervention on the attitudes to and perceptions of interprofessional ideals. Evaluation, over four years, of Nursing, Occupational Therapy, Podiatry, Prosthetics and Orthotics, Physiotherapy and Radiography students was performed using the adapted versions of the Readiness for Interprofessional Learning Scale (RIPLS) and the Interdisciplinary Education Perception Scale (IEPS). Baseline samples of the control and experimental groups were 260 and 313 respectively. Support for Interprofessional Education (IPE) appears high but possibly idealistically so initially. Restricted Maximum Likelihood (REML) models were used to assess intervention effects as well as any possible profession or time effects. The intervention was found to have had a significant effect on five of the measured sub-scales and the professions were found to react in a significantly different way on four of the sub-scales. The inclusion of a control group has confirmed previous findings from other studies but also highlights the possible effects of the general learning and teaching methodologies employed within various professions as well as the need for research into the influence of the timing, duration, style and content of clinical placement periods.

The Interdisciplinary Education Perception Scale (IEPS): an alternative remodelled sub-scale structure and its reliability.

The original 4 sub-scale version of the Interdisciplinary Education Perception Scale (IEPS) was published by Luecht et al. (1990, Journal of Allied Health, 181 - 191). There appears however to be a lack of evidence of the stability of the original instrument and of the test-retest reliability of the items and sub-scales when used with undergraduates. Given that during its development only 143 subjects completed the questionnaire which contained 18 items the generalizability of the instrument should perhaps have been investigated further. The Interprofessional Learning Group (IPL) at Glasgow Caledonian University has been using both the IEPS and the Readiness for Interprofessional Learning Scale (RIPLS) (Parsell & Bligh, 1999, Medical Education, 33, 95 - 100) to monitor changes in attitudes and perceptions of undergraduate students from eight different health and social care programmes. This paper reports the development of an alternative sub-scale model for the IEPS based on a sample of 308 students. Various aspects of the reliability of this revised model based on a subsequent data set of 247 students are also reported. This revised model appears to be stable for use with undergraduate students yielding Cronbach Alpha values for two of the sub-scales greater than 0.80 and test-retest weighted kappa values for items being fair to moderate.

Recurrence of spider naevi following treatment with 585 nm pulsed dye laser.

During a 2-year period 201 patients underwent treatment for spider naevi with a 585nm pulsed dye laser at Canniesburn Hospital Laser Suite. Patients were treated with a either single or double pulse technique. Of these patients 191 (95%) had a successful result, with clearance in a mean of 1.8 treatments (range, 1-7). There was no significant difference between the two treatment protocols in terms of probability of clearing the lesion or number of treatments required. These 191 patients were contacted by postal survey to determine their long-term results. The mean duration of follow-up was 37.9 months (range, 27-51 months). Response rate to the survey was 73%, 139 patients. Fifty patients (36%) had suffered recurrence of their spider naevi in the same site. There was no correlation found between the risk of recurrence and the site, number of treatments received, size and characteristics of the spider naevus, or treatment protocol used. The risk of recurrence increased with increasing age and was higher for peripheral facial lesions. The most common time of recurrence was between 6 and 18 months with 48% of recurrences occurring during this period. Existing published series, which have demonstrated low recurrence rates, have either had low numbers of patients or short follow-up periods of less than 6 months.

The test-retest reliability of a revised version of the Readiness for Interprofessional Learning Scale (RIPLS).

The original version of the Readiness for Interprofessional Learning Scale (RIPLS) was published by Parsell and Bligh in 1999. The only aspect of reliability considered by the authors was the internal consistency. A revised version for use with undergraduate students was published in 2005 (McFadyen et al., 2005). That paper also reported internal consistency of the revised version. Subsequently a sample from one professional group (n = 65) was used to assess test-retest reliability, over a one week period, of each of the 19 items and of the sub-scale totals, using Weighted Kappa and the intra-class correlation (ICC) respectively, and these results are reported in the present paper. The test-retest reliability of the individual items using Weighted Kappa was satisfactory, with the exception of two items (Items 11 and 12). The ICC results for the sub-scale totals were all in excess of 0.60 with the exception of sub-scale two. This revised version of RIPLS would appear to have good reliability in three of its sub-scales but further research, with larger samples, is required before the fourth sub-scale can be reliably assessed.

The efficiency of an air filtration system in the hospital ward.

A study was conducted to ascertain the efficiency and effectiveness of an air filtration system (Electromedia Model 100C, Clean Air UK, UK) in the hospital ward. The sampling was conducted using a portable Surface Air Sampler (Cherwell Laboratories, Bicester, UK) in conjunction with settle plates. Samples were taken two days before and two days following activation of the filtration system and results compared. A clear, demonstrable, statistically significant reduction in microbial organisms following the activation of the filtration systems is evident (81% settle plates; 24% Surface Air Sampler). This study has implications for the improved health and welfare of patients and healthcare workers who may benefit through the implementation of such a system.

The effect of exercise on gait and balance in patients with chronic fatigue syndrome.

This study investigated anecdotal reports of gait and balance abnormalities in subjects with Chronic Fatigue Syndrome (CFS) by examining the effects of a light exercise test on postural sway and various gait parameters. Tests were performed on 11 CFS patients and 11 age- and sex-matched sedentary controls. Results demonstrated that postural sway was not significantly different in both groups before or after the exercise test. There were, however, significant differences in gait parameters between the two groups confirming anecdotal evidence, but these differences were not exacerbated by the exercise test. Heart rate responses demonstrated that both groups were exercising at similar loads, although this was perceived to be higher by the CFS group.

Risks of respiratory disease in the heavy clay industry.

OBJECTIVES: Little information is available on the quantitative risks of respiratory disease from quartz in airborne dust in the heavy clay industry. Available evidence suggested that these risks might be low, possibly because of the presence in the dust of other minerals, such as illite and kaolinite, which may reduce the harmful effects of quartz. The aims of the present cross sectional study were to determine among workers in the industry (a) their current and cumulative exposures to respirable mixed dust and quartz; (b) the frequencies of chest radiographic abnormalities and respiratory symptoms; (c) the relations between cumulative exposure to respirable dust and quartz, and risks of radiographic abnormality and respiratory symptoms. METHODS: Factories were chosen where the type of process had changed as little as possible during recent decades. 18 were selected in England and Scotland, ranging in size from 35 to 582 employees, representing all the main types of raw material, end product, kilns, and processes in the manufacture of bricks, pipes, and tiles but excluding refractory products. Weights of respirable dust and quartz in more than 1400 personal dust samples, and site histories, were used to derive occupational groups characterised by their levels of exposure to dust and quartz. Full size chest radiographs, respiratory symptoms, smoking, and occupational history questionnaires were administered to current workers at each factory. Exposure-response relations were examined for radiographic abnormalities (dust and quartz) and respiratory symptoms (dust only). RESULTS: Respirable dust and quartz concentrations ranged from means of 0.4 and 0.04 mg.m-3 for non-process workers to 10.0 and 0.62 mg.m-3 for kiln demolition workers respectively. Although 97% of all quartz concentrations were below the maximum exposure limit of 0.4 mg.m-3, 10% were greater than this among the groups of workers exposed to most dust. Cumulative exposure calculations for dust and quartz took account of changes of occupational group, factory, and kiln type at study and non-study sites. Because of the importance of changes of kiln type additional weighting factors were applied to concentrations of dust and quartz during previous employment at factories that used certain types of kiln. 85% (1934 employees) of the identified workforce attended the medical surveys. The frequency of small opacities in the chest radiograph, category > or = 1/0, was 1.4% (median reading) and seven of these 25 men had category > or = 2/1. Chronic bronchitis was reported by 14.2% of the workforce and breathlessness, when walking with someone of their own age, by 4.4%. Risks of having category > or = 0/1 small opacities differed by site and were also influenced by age, smoking, and lifetime cumulative exposure to respirable dust and quartz. Although exposures to dust and to quartz were highly correlated, the evidence suggested that radiological abnormality was associated with quartz rather than dust. A doubling of cumulative quartz exposure increased the risk of having category > or = 0/1 by a factor of 1.33. Both chronic bronchitis and breathlessness were significantly related to dust exposure. CONCLUSIONS: Although most quartz concentrations at the time of this study were currently below regulatory limits in the heavy clay industry, high exposures regularly occurred in specific processes and occasionally among most occupational groups. However, there are small risks of pneumoconiosis and respiratory symptoms in the industry, although frequency of pneumoconiosis is low in comparison to other quartz exposed workers.

Demonstration of delayed recovery from fatiguing exercise in chronic fatigue syndrome.

Patients with the chronic fatigue syndrome (CFS) complain consistently of delay in recovery of peripheral muscle function after exercise. The purpose of this study was to try to confirm this observation. A fatiguing exercise test was carried out on the quadriceps muscle group of ten patients and ten control subjects. The test consisted of 18 maximum voluntary contractions (MVCs) with a 50% duty cycle (10 s contraction, 10 s rest), and the force generated by each contraction was recorded using a KinCom dynamometer. This was followed by a recovery phase lasting 200 min in which quadriceps strength was evaluated at increasing intervals, and a follow-up session at 24 h post-exercise involving three 10 s MVCs. Throughout the exercise period, the MVCs obtained from the control group were significantly higher than those of the patient group (P = 0.006), but both groups showed a parallel decline in force over the 18 contractions, in keeping with a similar endurance capacity. Recovery was prolonged in the patient group, however, with a significant difference compared to initial MVCs being evident during the recovery phase after exercise (P = 0.001) and also at 24 h (P < 0.001). In contrast, the control group achieved MVCs which were not significantly different from initial values during the recovery phase, and maintained these at 24 h. These findings support the clinical complaint of delayed recovery after exercise in patients with CFS.

Relations between upper limb soft tissue disorders and repetitive movements at work.

To make a preliminary assessment of whether upper limb soft tissue disorders might be associated with activities at work, we have conducted a case-control study of subjects attending orthopedic clinics in three cities. All subjects between the ages of 16 and 65 years, in whom defined soft tissue conditions of the upper limb were diagnosed by the participating orthopedic surgeons, were invited to take part. Controls were subjects attending the same clinics within the same age range whose clinical diagnosis did not include disease of the upper limb, cervical or thoracic spine. Information concerning repetitive movements of the upper limbs at work was elicited by questionnaire. Five hundred eighty cases and 996 controls were studied, representing 96% and 93%, respectively, of those invited to participate. The diagnoses of the cases included soft tissue conditions affecting the shoulder, elbow, forearm, wrist, thumb, hand, and fingers. The diagnoses of the controls included traumatic, degenerative, and inflammatory conditions, mostly of the legs and lower back. Women predominated among the cases (70%) and men among the controls (56%). Of 221 female cases with injury to the wrist and forearm, 32 were cleaner/domestics (14.5%) compared to 35 to 439 controls (8%), a difference statistically significant at the 2 1/2% level. Other jobs significantly overrepresented (5% level) among female cases with injuries at various anatomical sites included hairdressers, secretary/temps, assembly line workers, and machine operators (type unspecified). Among male cases, electricians were significantly overrepresented (5% level). Jobs for which there was a suggestion (p < 0.1) of overrepresentation among cases included butchers and teacher/lecturers (both males only) and the combined job groups (chosen a priori for analysis) of keyboard operators, machine operators, and music teachers (all three jobs, females only).

Development of the Regular Interlaboratory Counting Exchanges (RICE) scheme to include visual reference counts and samples from asbestos clearance operations.

The RICE proficiency testing scheme for asbestos fibre counting operated until 1992 with industrial samples and with reference counts produced by an image analyser (Magiscan). The visual counts produced in RICE by the participating laboratories have now been used to develop a reliable reference count for these industrial samples. Concurrently with the routine participation in RICE, laboratories also counted samples from asbestos clearance operations; these counts were used to develop suitable reference counts and performance limits for this type of sample. The width of this satisfactory performance interval is proportional to the natural variation in the data on the samples and is therefore a fixed interval on the log scale (of sample density) for high density samples and a fixed interval on the square-root scale for low density samples (where counting normally stops after a fixed number of fields). These developments led to the introduction of visual reference counts and clearance samples into RICE during 1992.

Leukocyte-mediated epithelial injury in ozone-exposed rat lung.

Both epithelial injury and inflammation are characteristic findings in the centriacinar regions of the lungs of rats exposed to ozone. In humans such effects could lead to long-term lung damage and disease. In animals, neoplastic change in the lungs after exposure to ozone has been described previously. The possible relationships between inflammatory cell recruitment, epithelial injury, and hyperplasia, with special regard to the important role of repair processes in leading to increased incidence of tumors in some species, have been addressed in the present study. We have previously described that leukocytes from lungs inflamed by different agents can injure epithelial cells in vitro. We have suggested that this leukocyte-mediated epithelial injury could enhance epithelial turnover in ozone-exposed lungs and so enhance the likelihood of tumor development. We, therefore, set out to test the hypothesis that bronchoalveolar leukocytes from ozone-exposed lungs can injure epithelial cells in vitro. PVG rats were exposed to 0.2, 0.4, 0.6, and 0.8 parts per million2 (ppm) ozone for seven hours per day for up to four days. On the morning following the last exposure, bronchoalveolar lavage was used to sample the bronchoalveolar leukocytes and the following parameters were assessed: total number, differential leukocyte count, production of oxidants, ability to degrade fibronectin, and ability to injure epithelial cells. In addition to these parameters, which were measured at all concentrations and time points in limited experiments, we also assessed macrophage size in short-term culture and inflammation in histological sections of lungs. Total number of lavageable cells was not affected by ozone inhalation. However, the percentage of macrophages decreased with ozone treatment and the percentage of neutrophils increased on days 1 and 2 at 0.6 and 0.8 ppm ozone. There was no significant effect of ozone exposure on the ability of neutrophils to degrade fibronectin or injure epithelial cells. Production of superoxide anion in response to stimulation with phorbol myristate acetate was significantly decreased by exposure to 0.6 ppm ozone, as described in previous studies. Macrophages from the lungs of rats exposed to ozone were larger than control macrophages.

Factors associated with the development of progressive massive fibrosis in British coalminers: a case-control study.

Possible associations between the incidence of progressive massive fibrosis (PMF) over periods of average length 11 years during 1963-80 and a range of explanatory variables, both environmental and medical, were examined in a study group of 4772 miners and ex-miners using case-control methods. Cases were members of the study group who developed PMF during the study period; controls were men who remained free of the disease. Cases and controls were matched on cumulative dust exposure to the start of the study period, colliery of employment, and whether or not employment before and during the study period had been at a single colliery only. Of 257 cases of PMF, 142 were matched to four controls each, 39 to three controls, 33 to two controls, and 31 to a single control only. Twelve cases could not be matched. Age and category of simple pneumoconiosis were each found to be associated with the incidence of PMF, confirming the results of many previous studies. Quetelet's index of body mass (a measure of weight, normalised for height) was found to differ considerably between cases and controls, cases tending to be lighter for their height. The difference did not vary significantly between three groups of collieries, defined by coal rank. Regression analysis confirmed the high level of statistical significance of the difference (p less than 0.001), allowing for the effects of age and prior category of simple pneumoconiosis. Of the environmental factors considered, an index of residence time of dust in the lungs was found to have the most statistically significant association with the incidence of PMF. The crudeness of the measure used, however, together with unreliability in estimates of early exposure to dust for some of the men studied, means that further work is necessary to investigate the magnitude and significance of this apparent association. In low and medium rank collieries there were large differences between the proportion of cases and controls showing a range of respiratory symptoms, cases consistently displaying a higher prevalence. In the high rank collieries of south Wales, however, symptoms occurred with equal frequency in cases and controls, the prevalence at these collieries being the same as among cases generally. Regression analysis (low and medium rank collieries only) showed that the presence of breathlessness was the symptom most strongly associated with the risk of attack of PMF, allowing for the effects of age and Quetelet's index.

Mortality of tar distillation workers.

Two hundred and fifty-five British tar distillery workers were followed from 1 January 1967 to 31 December 1983. Seventy-five men had died by the end of the follow-up, compared with 73.3 deaths expected on the basis of age-specific regional population death rates. Excess mortality occurred from lung cancer (12 deaths, 7.5 expected), bladder cancer (3 deaths, 0.7 expected) and diseases of the arteries and veins (5 deaths, 2.1 expected). Although the number of deaths from ischemic heart disease was not significantly increased overall (29 deaths, 25.3 expected), eight deaths from this cause occurred among men under 55 years of age compared with 3.9 expected. Four small matched case-referent studies, comparing men who died from these four causes with survivors, failed to reveal any associations between excess mortality and job type. In the light of other studies, it is concluded that the excess lung and bladder cancer mortality was work-related, while the deaths from ischemic heart disease and diseases of the arteries and veins merit further investigation.

Exposure to respirable coalmine dust and incidence of progressive massive fibrosis.

Data gathered since 1953 concerning more than 30,000 coalminers while employed at 24 collieries in England, Scotland, and Wales have been used to study the incidence of progressive massive fibrosis (PMF) in working coalminers. Results refer to 52,264 approximately five year intervals when the miners were at risk of an attack of PMF. One objective of the present study was to describe how the five year attack rate of PMF was related to miners' age, colliery, and simple pneumoconiosis category at the start of the periods at risk. The main objective was to estimate the relation between exposure to dust and incidence of PMF and to examine how this relation changes in the presence of coalworkers' simple pneumoconiosis (CWSP). Film readings, in some cases based on clinical assessments only, showed 462 attacks of PMF over the five year risk periods. The men concerned had experienced higher cumulative exposures to dust than their colleagues of similar age at the same collieries, a result found at 65 of the 68 age colliery groups where an attack had occurred. The association was highly significant statistically. Simple pneumoconiosis clearly predisposed to PMF, with five year attack rates of 13.9%, 12.5%, 4.4%, and 0.2% among men with categories 3, 2, 1, and 0 respectively at the start of the risk periods. Once simple pneumoconiosis category 1 or more had been attained, those with higher cumulative exposure to dust were not at greater risk of an attack of PMF than other men with the same CWSP category. Among most miners, those with category 0, however, the risks of an attack of PMF increased clearly with exposure. Risks of an attack were higher among older men irrespective of CWSP category. In addition, there were large colliery specific variations in incidence related to variations in the carbon content of the coal though not fully explained by them. It is concluded that cumulative exposure to respirable dust is the decisive central factor in the development of PMF. Its effect is primarily in causing simple pneumoconiosis category 1 or higher which predisposes to PMF, though the dust related incidence among men with category 0 is not negligible in view of the large numbers at risk. Continuation of the policy to minimise dust concentrations underground therefore seems the only secure strategy to limit, and eventually eliminate, PMF.

Environmental surveys in the European man-made mineral fiber production industry.

This paper presents estimates of airborne fiber concentrations and fiber size for European man-made mineral fiber (MMMF) factories on the basis of measurements made in 1977-1980. The airborne fiber concentrations previously reported at a conference of the World Health Organization (WHO) and the International Agency for Research on Cancer in 1982 have been revised to harmonize the results with the WHO-European MMMF reference counting level. The result was an approximate doubling of the reported airborne fiber levels. After the revisions the average combined occupational group concentrations in the rock- and glass-wool plants were still generally low (less than 0.01 fibers/ml). In the glass continuous-filament factories the airborne fiber concentrations were very low (less than 0.01 fibers/ml). The average plant median for fiber length ranged from 10 to 20 microns, and the corresponding median diameters ranged from 0.7 to 2 microns. In general the glass-wool fibers were thinner than the rock-wool fibers. The fiber concentrations measured in other studies in the MMMF production and user industries are reviewed. Higher levels (between 0.1 and 1.0 fibers/ml) have been measured in some insulation wool production, secondary production, and user industries. The highest levels (greater than 1.0 fibers/ml) occurred in very fine glass-fiber production and in other specialist insulation wool usage.

Quantitative relations between exposure to respirable coalmine dust and coalworkers' simple pneumoconiosis in men who have worked as miners but have left the coal industry.

Present estimates of the quantitative relations between exposure to mixed respirable coalmine dust and risk of developing coalworkes' simple pneumoconiosis are based on studies of working miners. These studies did not include men who had been miners but had left the coal industry, and it was not known whether the estimates of risk were also appropriate for these men. The results are reported of a study in which the dust/disease relations in men who have been miners but have left the industry have been compared with those in men who have remained in it. A sample of 17738 men who were first examined when working in 24 British collieries in the 1950s has been followed up about 22 years later. It was possible to examine 61% of the survivors, 44% of the original sample. Simple pneumoconiosis was more frequent among men (particularly older men) who had left the industry than among those who had stayed in it. A detailed analysis did not show any systematic or statistically significant difference between men who stayed and men who left in the quantitative relations between dust exposure and simple pneumoconiosis. Present estimates of risk of simple pneumoconiosis in relation to exposure to mixed respirable dust in working miners adequately describe the relation found in men who have been miners but have left the industry.