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Biomedical subjects

J Cherrie

Publications and source records attributed to J Cherrie.

15 recordsLinked to original sources
PubMed2005

The London Underground: dust and hazards to health.

AIMS: To assess hazards associated with exposure to dust in the London Underground railway and to provide an informed opinion on the risks to workers and the travelling public of exposure to tunnel dust. METHODS: Concentrations of dust, as mass (PM2.5) and particle number, were measured at different underground stations and in train cabs; its size and composition were analysed; likely maximal exposures of staff and passengers were estimated; and in vitro toxicological testing of sample dusts in comparison with other dusts was performed. RESULTS: Concentrations on station platforms were 270-480 microg/m3 PM2.5 and 14,000-29,000 particles/cm3. Cab concentrations over a shift averaged 130-200 microg/m3 and 17,000-23,000 particles/cm3. The dust comprised by mass approximately 67% iron oxide, 1-2% quartz, and traces of other metals, the residue being volatile matter. The finest particles are drawn underground from the surface while the coarser dust is generated by interaction of brakes, wheels, and rails. Taking account of durations of exposure, drivers and station staff would have maximum exposures of about 200 microg/m3 over eight hours; the occupational exposure standard for welding fume, as iron oxide, is 5 mg/m3 over an eight hour shift. Toxicology showed the dust to have cytotoxic and inflammatory potential at high doses, consistent with its composition largely of iron oxide. DISCUSSION: It is unjustifiable to compare PM2.5 exposure underground with that on the surface, since the adverse effects of iron oxide and combustion generated particles differ. Concentrations of ultrafine particles are lower and of coarser (PM2.5) particles higher underground than on the surface. The concentrations underground are well below allowable workplace concentrations for iron oxide and unlikely to represent a significant cumulative risk to the health of workers or commuters.

Air Pollutants↗
PubMed1999

Particulate air pollution and the blood.

BACKGROUND: Particulate air pollution has been associated with excess deaths from, and increases in hospital admissions for, cardiovascular disease among older people. A study was undertaken to determine whether this may be a consequence of alterations in the blood, secondary to pulmonary inflammation caused by the action of fine particles on alveolar cells, by repeatedly measuring haematological factors in older people and relating them to measurements of exposure to airborne particles. METHODS: One hundred and twelve individuals aged 60+ years in two UK cities provided repeated blood samples over 18 months, 108 providing the maximum of 12 samples. Estimates of individual exposure to particles of less than 10 microm diameter (PM(10)), derived from a mathematical model based on activity diaries and comparative measurements of PM(10) at multiple sites and during a variety of activities, were made for each three day period prior to blood sampling. The relationships between blood values and estimates of both personal exposure and city centre measurements of PM(10) were investigated by analysis of covariance, adjusting for city, season, temperature, and repeated individual measurements. RESULTS: Estimated personal exposure to PM(10) over the previous three days showed negative correlations with haemoglobin concentration, packed cell volume (PCV), and red blood cell count (p<0.001), and with platelets and factor VII levels (p<0.05). The changes in red cell indices persisted after adjustment for plasma albumin in a sample of 60 of the subjects. City centre PM(10) measurements over three days also showed negative correlations with haemoglobin and red cell count (p<0.001) and with PCV and fibrinogen (p<0.05), the relationship with haemoglobin persisting after adjustment for albumin. C reactive protein levels showed a positive association with city centre measurements of PM(10) (p<0.01). Based on a linear relationship, the estimated change in haemoglobin associated with an alteration in particle concentration of 100 microg/m(3) is estimated to have been 0.44 g/dl (95% CI 0.62 to 0.26) for personal PM(10) and 0.73 g/dl (95% CI 1.11 to 0.36) for city centre PM(10) measurements. CONCLUSIONS: This investigation is the first to estimate personal exposures to PM(10) and to demonstrate associations between haematological indices and air pollution. The changes in haemoglobin adjusted for albumin suggest that inhalation of some component of PM(10) may cause sequestration of red cells in the circulation. We propose that an action of such particles either on lung endothelial cells or on erythrocytes themselves may be responsible for changing red cell adhesiveness. Peripheral sequestration of red cells offers an explanation for the observed cardiovascular effects of particulate air pollution.

Aged↗
PubMed1997

Cancer mortality among man-made vitreous fiber production workers.

We have updated the follow-up of cancer mortality for a cohort study of man-made vitreous fiber production workers from Denmark, Finland, Norway, Sweden, United Kingdom, Germany, and Italy, from 1982 to 1990. In the mortality analysis, 22,002 production workers contributed 489,551 person-years, during which there were 4,521 deaths. Workers with less than 1 year of employment had an increased mortality [standardized mortality ratio (SMR) = 1.45; 95% confidence interval (CI) = 1.37-1.53]. Workers with 1 year or more of employment, contributing 65% of person-years, had an SMR of 1.05 (95% CI = 1.02-1.09). The SMR for lung cancer was 1.34 (95% CI = 1.08-1.63, 97 deaths) among rock/slag wool workers and 1.27 (95% CI = 1.07-1.50, 140 deaths) among glass wool workers. In the latter group, no increase was present when local mortality rates were used. Among rock/slag wool workers, the risk of lung cancer increased with time-since-first-employment and duration of employment. The trend in lung cancer mortality according to technologic phase at first employment was less marked than in the previous follow-up. We obtained similar results from a Poisson regression analysis limited to rock/slag wool workers. Five deaths from pleural mesothelioma were reported, which may not represent an excess. There was no apparent excess for other categories of neoplasm. Tobacco smoking and other factors linked to social class, as well as exposures in other industries, appear unlikely to explain the whole increase in lung cancer mortality among rock/slag wool workers. Limited data on other agents do not indicate an important role of asbestos, slag, or bitumen. These results are not sufficient to conclude that the increased lung cancer risk is the result of exposure to rock/slag wool; however, insofar as respirable fibers were an important component of the ambient pollution of the working environment, they may have contributed to the increased risk.

Aged↗
PubMed1995

Individual exposure to particulate air pollution and its relevance to thresholds for health effects: a study of traffic wardens.

OBJECTIVE: To investigate the differences between measurements of personal exposure to particulate air pollution and static area measurements in a group of people working close to traffic and to determine whether such differences might obscure any threshold for health effects in epidemiological studies. METHODS: Personal air sampling was carried out on two groups of eight traffic wardens for four days on two consecutive weeks in November 1994. These measurements were compared with standard environmental static sampling data that were obtained for the same period. A simulation with log normal distributions of personal exposures was produced, and an arbitrary risk calculated for each exposure, assuming a threshold of 50 micrograms/m3, and an exposure-response curve was calculated. RESULTS: The median concentration for personal samplers in week 1 was 123 micrograms/m3 and 41 micrograms/m3 in week 2. Corresponding area concentrations were 10 micrograms/m3 and 7.5 micrograms/m3. The differences between the personal and area results were significant, as were the differences for personal sampling between weeks 1 and 2. The simulation showed that the variation in individual exposures around an area sampler obscured the threshold. CONCLUSIONS: Area sampling data may be of limited value in the investigation of the biological effects of exposure to pollution and their use may result in real thresholds being obscured. Personal exposure assessment may be crucial in determination of the health effects attributable to different concentrations of air pollutants.

Adult↗
PubMed1991

Clinical and biologic features of childhood T-cell leukemia with the t(11;14).

Cytogenetic analysis of cells from 622 consecutive patients with newly diagnosed acute lymphoblastic leukemia (ALL) and successful G-banding chromosome studies disclosed seven cases with the t(11;14)(p13;q11) and one with the t(11;14)(p15;q11). Leukemia cells in all eight cases had a T-cell immunophenotype. The t(11;14)(p13;q11) occurred in 6.8% and the t(11;14)(p15;q11) in 1% of T-cell ALL cases (n = 103). The t(11;14) was associated with presenting clinical features typical of T-cell ALL: male predominance (n = 6), age greater than 10 years (n = 3), hyperleukocytosis (white blood cells greater than 100 x 10(9)/L, n = 5), relatively high hemoglobin level (median, 10.8 g/dL), high serum lactic dehydrogenase level (median, 3248 U/L), presence of mediastinal mass (n = 6), and central nervous system leukemia (n = 2). While there were no significant differences in presenting features between T-cell ALL cases with or without the t(11;14), leukemic cells from patients with the translocations were more likely to coexpress CD4 and CD8 antigens (6 of 6 v 35 of 86 cases tested, P less than .05). Adverse events have occurred in six patients: three central nervous system relapses [including the one with t(11;14)(p15;q11)], two secondary acute myeloid leukemia, and one hematologic relapse. Our results indicate that the t(11;14)(p13;q11) occurs exclusively in T-cell malignancies of intermediate- or late-stage thymocyte differentiation. Additional studies are needed to determine the prognostic implications of these translocations.

Adolescent↗
PubMed1991

Lower prevalence of the debrisoquin oxidative poor metabolizer phenotype in American black versus white subjects.

Our objective was to determine whether there are differences in debrisoquin hydroxylase (P450IID6) activity between American black subjects and white subjects. Phenotype was assigned in a group of 586 unrelated white and black children with use of dextromethorphan as the substrate probe. Restriction fragment length polymorphism analysis of genomic deoxyribonucleic acid (DNA) was performed in a subset of subjects by use of a full length complementary DNA for P450IID6. Thirty-seven of 480 (7.7%) white children were poor metabolizers compared with 2 of 106 (1.9%) black children (p = 0.03). Among 41 white subjects and 18 black subjects, there were significant differences (p less than 0.05) in two XbaI DNA restriction fragments; the 44 kb fragment was more common and the 29 kb fragment was less common in black versus white extensive metabolizers. There is a lower prevalence of the debrisoquin poor metabolizer phenotype among American black persons, which could have implications for efficacy or toxicity of drugs metabolized by this enzyme, as well as for racial differences in the prevalence of diseases associated with the debrisoquin oxidative phenotype.

Black People↗
PubMed1991

A phase I clinical trial of 2-chlorodeoxyadenosine in pediatric patients with acute leukemia.

To evaluate its toxicity and clinical efficacy in children with relapsed or refractory leukemia, we performed a phase I trial of 2-chloro-2'-deoxy-adenosine (2-chlorodeoxyadenosine; 2-CDA) given as a continuous 5-day infusion at doses of 3 to 10.7 mg/m2/d. In this study of 31 children with acute leukemia, the only dose-limiting toxicity was myelosuppression. At the highest dose level, three of seven patients developed fatal systemic bacterial or fungal infections. At dose levels above 6.2 mg/m2/d, significant oncolytic responses occurred in all patients. In addition, there was a significant correlation between both the responsiveness by cell type and dose of 2-CDA, such that more oncolytic responses were noted in acute myeloid leukemia (AML) patients than acute lymphoblastic leukemia (ALL) patients (P = .02). Although this was a phase I trial in heavily pretreated patients with refractory disease, two AML patients treated at 5.2 and 10.7 mg/m2/d, respectively, had complete hematologic responses, and one patient treated at 10.7 mg/m2/d had a partial response. In addition, there was a dose-response relationship in all patients with improved cytoreduction of peripheral blast cells at higher doses of 2-CDA. In vitro evaluation of 2-CDA uptake and anabolism by leukemic blast cells from 22 patients demonstrated that 2-chloro-2'-deoxyadenosine (Cld-AMP) and 2-chloro-2'-deoxyadenosine 5'-striphosphate (CldATP) reached concentrations close to steady-state levels within 1 hour. Intracellular nucleotide disappearance rates were high with half-lives of 1.29 and 2.47 hours for CldAMP and CldATP, respectively. This suggests that continuous infusion is necessary to maintain the desired plasma concentration. The results of this study confirm the antileukemic activity of 2-CDA and the lack of prohibitive nonhematologic toxicity. Phase II trials in patients with AML and ALL are warranted.

2-Chloroadenosine↗
PubMed1989

Comparative studies of airborne asbestos in occupational and non-occupational environments using optical and electron microscope techniques.

We have compared asbestos fibre and general fibre counts from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with fibre counts from phase-contrast optical microscope (PCOM) methods. Three different types of sample have been evaluated: laboratory-prepared samples of different fibre types; chrysotile asbestos textile factory samples; and non-occupational and environmental samples from sites where asbestos might be found. TEM produced total fibre number assessments which were greater than those found with SEM which, in turn, produced fibre counts greater than those obtained with the PCOM. However, when fibres longer than 5 microns were alone counted, the two electron microscope (EM) methods provided similar results. This indicates that TEM is advantageous in comparison with SEM when counting or sizing short fibres and has no advantage for fibres longer than 5 microns. For fibres longer than 5 microns in both the laboratory-prepared and asbestos factory samples, the EM asbestos counts were higher than the PCOM fibre counts, the ratios depending on the fibre type in the case of the former. The PCOM fibre counts in samples from the non-occupational situations were shown to be poor predictors of airborne asbestos fibre concentrations determined by EM. This was mainly due to the presence of high and variable proportions of non-asbestos fibres in these samples. It is concluded that, in order to convert EM asbestos fibre concentrations (greater than 5 microns) to equivalent PCOM asbestos concentrations, they should be divided by 4.0 for chrysotile and 1.7 for amphibole asbestos.

Air Pollutants↗
PubMed1986

Updating lung cancer mortality among a cohort of man-made mineral fibre production workers in seven European countries.

A historical cohort of 21,967 workers ever employed in 13 European factories manufacturing various types of man-made mineral fibres (MMMF) was observed until 1982. Overall there were 2719 deaths (standardised mortality ratio (SMR) = 111) of which 189 were from lung cancer (SMR = 125). For the glasswool and rockwool/slagwool production subcohorts the lung cancer SMRs rose with time since first exposure, exceeding 170 for the period of 30 or more years. Adjustment for regional variations in mortality substantially reduced the excess in the glasswool group, but not in the rockwool/slagwool. In neither subgroup was there any relationship of lung cancer mortality with length of employment. During the early years of rockwool/slagwool production there was the potential for much higher fibrous dust exposure than at present, because of the absence of dust suppressing oil and/or the use of a batch production process. In addition slag was widely used as a raw material. Amongst workers employed during the early phase, there were 10 lung cancer deaths giving SMRs of 270 and 244 for the periods 20-29 and 30 or more years since first exposure. This group accounts for most of the absolute excess of lung cancer for the rockwool/slagwool plants.

Adult↗
PubMed1986

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.

Air Pollutants, Occupational↗
PubMed1986

Past exposures to airborne fibers and other potential risk factors in the European man-made mineral fiber production industry.

A historical environmental investigation was undertaken in European man-made mineral fiber factories (MMMF). The aim was to assess past exposures to MMMF and other environmental risk factors (asbestos, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, formaldehyde, and arsenic). A self-administered questionnaire completed by each plant management and an interview of the respondents were used. Addition of oil to the MMMF, change in the nominal fiber size of the bulk MMMF, and elimination of early discontinuous production techniques were identified as principal changes. The absence of oil, small nominal size, and labor-intensive production have been judged to be associated with higher airborne fiber levels. It was concluded that for epidemiologic purposes the subdivision of the history of each plant into an early, intermediate, and late technological phase based on the aforementioned changes would be appropriate. Corresponding time periods were identified for asbestos usage, use of bitumen as a binder, and production of slag wool. Two factories were singled out for specific attention: one where asbestos was used in calcium silicate brick production and one where olivine, used as a raw material, may have been contaminated with natural mineral fibers and where the production process would have exposed workers to coal-tar pitch volatiles.

Air Pollutants, Occupational↗
PubMed1986

The man-made mineral fiber European historical cohort study. Extension of the follow-up.

The study concentrated on 21,967 workers producing rock wool/slag wool, glass wool or continuous filament in 13 European factories. The expected deaths and incident cancer cases were derived from multiplying the accumulated person-years by national reference rates across sex, age, and calendar-year strata, correction factors for regional lung cancer mortality also being used. Exposure assessment was based on the results of a historical environmental investigation reported elsewhere. There were 189 deaths (151.2 expected), and for rock-wool/slag-wool and glass-wool workers the standardized mortality ratios for lung cancer showed a pattern of increasing mortality with time since first exposure but not duration of employment. There was an excess of lung cancer among rock-wool/slag-wool workers employed during an early technological phase before the introduction of dust-suppressing agents, and fiber exposure, either alone on in combination with other exposures, may have contributed to the elevated risk. No excess of the same magnitude was evident for glass-wool production, and the follow-up of the continuous filament cohort was too short to allow for an evaluation of possible long-term effects. There was no evidence of an increased risk for pleural tumors or nonmalignant respiratory diseases.

Calcium Compounds↗