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Biomedical subjects

C A Pickering

Publications and source records attributed to C A Pickering.

At least 19 recordsLinked to original sources
PubMed1992

An investigation of the relationship between microbial and particulate indoor air pollution and the sick building syndrome.

The sick building syndrome has been the subject of research for approximately 10 years. Although it is often suggested that symptoms in office workers are due to circulating micro-organisms or particles, epidemiological studies investigating the relationship between them have been lacking. This cross-sectional study has combined medical and aerobiological assessments of offices in Great Britain and has found that, although airborne particulates and micro-organisms are unlikely to be the sole cause of the sick building syndrome, positive associations between symptom prevalence rates and levels of airborne viable bacteria and fungi within groups of buildings with similar ventilation systems, suggest a possible causal link that should be explored.

Air Microbiology↗
PubMed1992

A study of the performance and comparability of the sampling response to cotton dust of work area and personal sampling techniques.

In order to compare and contrast the sampling response to cotton dust of two forms of dust sampling 85 work areas were identified over a 2-year period for investigation in eight Lancashire spinning mills. Three hundred and five work area dust samples were undertaken and 252 personal dust samples were performed. Operatives who spent a minimum of 80% of their working shift in the area in which work area sampling was also performed were selected for personal sampling. Work area dust exposures have recently shown an upward trend, with highest concentrations occurring in the ring spinning room (median 1.15 mg m-3, range 0.82-2.06). Personal dust samples showed a reduction in dust exposures as cotton processing progressed, from a high in the opening room (median value of 6.24 mg m-3, range 1.0-41.5) to a minimum of 1.02 mg m-3 (range 0.30-0.93) in the winding room. The ratio of measured personal sampling dust exposure to work area sampling exposure was used to compare the relative performance of the two techniques. This ratio was highest in the early processes. There was a 7.8-fold difference in measurement between the two techniques in the opening processes, falling to 4.9 in carding and 4.2 in the other card-room processes. However in ring spinning the ratio was only 1.4, suggesting a degree of comparability in the methods at this stage of processing. The value rose to 2.5 for the last stage (winding). Respiratory disease is known to occur predominantly in the early stages of processing (opening and carding) where high dust concentrations are found using the personal technique. These data support the use of personal sampling for setting exposure limits to cotton dust in preference to the current recommended method using work area sampling techniques, which may significantly underestimate dust exposure in the high risk work areas and is outdated.

Dust↗
PubMed1992

Absence of seasonal variation in concentrations of the house dust mite allergen Der p1 in south Manchester homes.

BACKGROUND: House dust mite numbers and the concentration of its main allergen, Der p1, depend on ambient temperature and humidity and have been reported to show a seasonal variation in homes in the United States. A study was designed to find out whether Der p1 concentrations vary with the seasons in dust collected from homes in north west England. METHODS: The concentration of Der p1 was measured in dust, collected every three months from April 1990 to April 1991, from mattresses and from bedroom and living room carpets in 40 houses in the south Manchester area. Twenty four hour recordings of indoor relative humidity were made in 20 houses during the sampling day. RESULTS: Mean concentrations of Der p1 from all three sources rose two to three fold in October. This was in contrast to the 1000 fold variation in concentrations of Der p1 present between houses within each season's sample and less than the 10 fold change considered to be of clinical importance. The autumn increase was paralleled by a rise in humidity. There was no statistical correlation, however, between Der p1 concentrations and relative humidity, house type, ventilation, or double glazing. CONCLUSIONS: The results suggest that seasonal variations in exposure to Der p1 exposure in north west England are small and unlikely to be of major clinical importance. The temperature and humidity data showed that the indoor environment remained relatively constant and conducive to mite growth throughout the year.

Allergens↗
PubMed1992

Lung function, bronchial reactivity, atopic status, and dust exposure in Lancashire cotton mill operatives.

A total of 645 cotton mill operatives were administered a respiratory questionnaire. Of these, 85 (13.2%) complained of one or more work-related respiratory symptoms: 23 (3.6%) had byssinosis and the remaining 62 had symptoms not conforming to byssinosis (nonbyssinotic symptomatics, NBS). All byssinotic, 56 NBS, and 84 matched asymptomatic operatives underwent pulmonary function testing (FEV1 and FVC), skin testing to common allergens, and histamine bronchial challenge. Work area and personal breathing zone cotton dust concentrations were assessed, and a cumulative cotton dust exposure index was calculated for each individual. Byssinotic, NBS, and asymptomatic operatives all had reduced FEV1; observed mean liters (95% CI); predicted mean: byssinosis, 2.36 (2.09 to 2.63), 3.02; NBS, 2.94 (2.71 to 3.17), 3.29; and asymptomatic, 3.12 (2.95 to 3.29), 3.31. Only byssinotic subjects had evidence of impaired FVC: 3.31 (2.97 to 3.65), 3.69. The majority of byssinotic operatives (18 of 23) had bronchial hyperreactivity (BHR) in comparison with 21 of 56 NBS and 14 of 84 asymptomatic operatives. Mean log PD20 (95% CI) values were significantly lower in the byssinotic group -0.72 (-1.42, -0.02) than in NBS 0.57 (0.08, 1.06) and asymptomatic subjects 0.57 (-0.26, 1.39). The distribution of atopy did not differ significantly between groups, and lung function did not differ significantly between atopic and nonatopic subjects. The cumulative cotton dust exposure index was the only dust parameter to be significantly greater in those with BHR (mean mg-yr/m3 [95% CI] 14.13 [13.1 to 15.1]) than those with normal reactivity [5.35 (3.9 to 6.8)].

Adult↗
PubMed1988

Cadmium fume inhalation and emphysema.

Lung function and chest radiographs of 101 men who had worked for 1 or more years manufacturing copper-cadmium alloy were compared with those of a referent group matched for age, sex, and employment status. Cigarette consumption was similar in the two groups. The cadmium workers had an excess of abnormalities of lung function and of radiographic changes consistent with emphysema. Classification of the cadmium workers by exposure categories based on either estimated cumulative cadmium exposure or liver cadmium measured by neutron activation analysis showed that abnormalities of lung function were greatest in those with the highest cumulative cadmium exposure or liver cadmium. The difference in the transfer coefficient (KCO) between cadmium workers and referents increased linearly with increasing cumulative exposure without evidence for a threshold. The estimated mean decrement in KCO for a cadmium worker employed 5 or more years with a cumulative exposure of 2000 yr.microgram.m-3 (exposure to the current UK control limit of 50 micrograms.m-3 for a working lifetime of 40 yr) lies between 0.05 and 0.3 mmol.min-1.kPa-1.l-1 (95% confidence interval). This decrement is consistent with the functional and radiological changes of emphysema observed in this group of workers.

Aged↗
PubMed1988

Recent trends in the prevalence of byssinotic symptoms in the Lancashire textile industry.

A respiratory symptoms questionnaire was completed for 4656 volunteers employed in 31 textile factories engaged in spinning or weaving manmade fibre or cotton of various qualities. Sets of airborne dust and bacteria samples were collected in workzones and personal breathing zones in the workrooms where the volunteers were employed. A total of 182 people indicated experiencing byssinotic symptoms, mainly in opening and carding rooms or in spinning and winding rooms where medium to coarse cotton was being processed. This represents a significant decline in the prevalence of byssinotic symptoms over the years, due possibly to lower concentrations of airborne contaminants, especially of bacteria, as cleaner raw materials are being used. According to a multiple, logistic regression model, the prevalence of byssinotic symptoms was found to be statistically significantly related to years worked in the cotton industry, exposure to dust, quality of cotton used, workroom of employment, ethnic origin, and smoking habits. Symptoms of chronic bronchitis were found to be significantly related to smoking habit and to factors connected with occupation, such as exposure to dust, workroom, and the quality of fibre processed.

Byssinosis↗
PubMed1987

Manchester air disaster.

On 22 August 1985 a fire occurred on a Boeing 737 jet airliner at take off at Manchester Airport. One hundred and thirty seven passengers and crew were on board. Fifty two passengers died on the aircraft, 85 escaped. Most survivors had minor physical injuries, but 15 required admission to hospital because of smoke inhalation and two of these had severe burns. At presentation only one survivor required ventilation but within 12 hours a further five required ventilation. Although initially patients suffering from smoke inhalation may seem relatively well, lung function may deteriorate rapidly in the first 24 hours. Careful organisation and regular practice of procedures to deal with a major accident are essential to be able to respond adequately to such an event.

Accidents, Aviation↗
PubMed1987

Amoebae and humidifier fever.

One hundred and nineteen sera from workers at four different work sites exposed to different contaminated humidifiers were examined by the immunofluorescent antibody (IFA) technique for antibodies to the amoebae Acanthamoeba polyphaga and Naegleria gruberi. Twenty-five of the sera were from workers with humidifier fever (HF) and six from workers with work related asthma (WRA) shown to be due to the contaminated humidifiers. A positive IFA test was found to correlate precipitin reaction to humidifier antigen, but did not correlate with smoking habit, work related symptoms (detected by standard questionnaire) or with HF or WRA. Amoebae were identified in all humidifiers studied.

Amoeba↗
PubMed1985

Occupational asthma in a steel coating plant.

An outbreak of occupational asthma, of unknown cause and extent, was detected in a steel coating plant. In 1979 a cross-sectional study which defined occupational asthma in terms of respiratory symptoms detected 21 people with suggestive symptoms among the 221 studied. They all worked in the coating shop, but the plastic coatings used at the plant contained many potential sensitising agents that might have caused the asthma. All 21 developed their symptoms after 1971, and it was found that in this year a supplier had modified a coating allowing, at the temperatures used in the process, toluene di-isocyanate to be liberated. Two of the symptomatic subjects were tested by inhalation of the isocyanate and showed asthmatic reactions and other subjects were found to have asthma related to periods spent at work by records of peak expiratory flow rate. Over half the 21 had a symptom free latent period after first exposure of three years or less, a pattern not seen in other subjects with respiratory symptoms. After the isocyanate had been removed from the process 17 of these subjects became asymptomatic or improved, a greater proportion than in other subjects with respiratory symptoms.

Adult↗