Blackawton bees.

BACKGROUND: Real science has the potential to not only amaze, but also transform the way one thinks of the world and oneself. This is because the process of science is little different from the deeply resonant, natural processes of play. Play enables humans (and other mammals) to discover (and create) relationships and patterns. When one adds rules to play, a game is created. THIS IS SCIENCE: the process of playing with rules that enables one to reveal previously unseen patterns of relationships that extend our collective understanding of nature and human nature. When thought of in this way, science education becomes a more enlightened and intuitive process of asking questions and devising games to address those questions. But, because the outcome of all game-playing is unpredictable, supporting this 'messyness', which is the engine of science, is critical to good science education (and indeed creative education generally). Indeed, we have learned that doing 'real' science in public spaces can stimulate tremendous interest in children and adults in understanding the processes by which we make sense of the world. The present study (on the vision of bumble-bees) goes even further, since it was not only performed outside my laboratory (in a Norman church in the southwest of England), but the 'games' were themselves devised in collaboration with 25 8- to 10-year-old children. They asked the questions, hypothesized the answers, designed the games (in other words, the experiments) to test these hypotheses and analysed the data. They also drew the figures (in coloured pencil) and wrote the paper. Their headteacher (Dave Strudwick) and I devised the educational programme (we call 'i,scientist'), and I trained the bees and transcribed the childrens' words into text (which was done with smaller groups of children at the school's local village pub). So what follows is a novel study (scientifically and conceptually) in 'kids speak' without references to past literature, which is a challenge. Although the historical context of any study is of course important, including references in this instance would be disingenuous for two reasons. First, given the way scientific data are naturally reported, the relevant information is simply inaccessible to the literate ability of 8- to 10-year-old children, and second, the true motivation for any scientific study (at least one of integrity) is one's own curiousity, which for the children was not inspired by the scientific literature, but their own observations of the world. This lack of historical, scientific context does not diminish the resulting data, scientific methodology or merit of the discovery for the scientific and 'non-scientific' audience. On the contrary, it reveals science in its truest (most naive) form, and in this way makes explicit the commonality between science, art and indeed all creative activities. PRINCIPAL FINDING: 'We discovered that bumble-bees can use a combination of colour and spatial relationships in deciding which colour of flower to forage from. We also discovered that science is cool and fun because you get to do stuff that no one has ever done before. (Children from Blackawton)'.

Lymphohaematopoeitic cancer mortality among workers with benzene exposure.

Lymphohaematopoeitic cancer mortality was examined among 4417 workers at a chemical plant by cumulative and peak benzene exposure. There was little evidence of increasing risk with increasing cumulative exposure for all leukaemias or acute non-lymphocytic leukaemias (ANL), or the other lymphohaematopoeitic cancers with the exception of multiple myeloma. For multiple myeloma, the SMRs were 1.1 (95% CI 0.3 to 2.5) in the non-exposed group, 1.4 (95% CI 0.2 to 5.1) in the <1 ppm-years, 1.5 (95% CI 0.2 to 5.4) in the 1-6 ppm-years, and 2.6 (95% CI 0.7 to 6.7) in the >6 ppm-years group. We found no trends by peak exposures for any of the cancers. However, when peak exposures over 100 ppm for 40 or more days were considered, the observed number of all leukaemias (SMR = 2.7, 95% CI 0.8 to 6.4), ANL (SMR = 4.1, 95% CI 0.5 to 14.9), and multiple myeloma (SMR = 4.0, 95% CI 0.8 to 11.7) were greater than expected. While the observed number of deaths is small in this study, the number of peak exposures greater than 100 ppm to benzene is a better predictor of risk than cumulative exposure. The dose rate of benzene and a threshold for exposure response may be important factors for evaluating lymphohaematopoietic risk.

Cancer among farmers: a meta-analysis.

PURPOSE: We conducted a meta-analysis of 37 studies to assess whether farmers had elevated rates for several cancers, as was concluded in a previous meta-analysis of 21 studies. METHODS: We identified studies from the reference list of the previous meta-analysis and from a MEDLINE search through December 31, 1994. The primary purpose of our analysis was to identify and, if possible, understand the sources of heterogeneity in the literature. Stratified analyses of studies and linear modeling with inverse variance weights were used to assess the impact of study characteristics on results. We calculated summary relative risks as a weighted average of the log relative risks across studies using inverse variance weights. Fixed and random effects models were used as appropriate. RESULTS: The results for most cancers were markedly heterogeneous by study design and, for fewer cancers, by geographic location, and whether the studies focused on crop and livestock farmers. There was some indication of publication bias due to underreporting of near null or sub null findings. Lip cancer was the only cancer that was clearly elevated among farmers. CONCLUSIONS: The results do not suggest that farmers have elevated rates of several cancers. However, the known heterogeneity of exposures by type of farming, geographic area, time period, and other factors limits the informativeness of meta-analyses of these studies for assessing potential carcinogenic exposures in agriculture.

Cancer mortality among workers with benzene exposure.

We updated a cohort mortality study of 4,172 workers at a chemical plant to examine cancer mortality among workers exposed to low levels of benzene. Overall mortality [standardized mortality ratio (SMR) = 1.0; 95% confidence interval (CI) = 0.9-1.1] and cancer mortality (SMR = 1.0; 95% CI = 0.8-1.3) rates were at expected levels for production workers with benzene exposure. We observed elevated, albeit imprecise, rates of leukemia (SMR = 2.3; 95% CI = 0.7-5.3) and multiple myeloma (SMR = 2.3; 95% CI = 0.7-9.4) in this group of workers. The leukemias and multiple myelomas occurred predominantly among workers 20 or more years after first exposure. The leukemias were not restricted to acute myelogenous subtypes, and they occurred predominantly among workers hired before 1950 at exposure levels lower than previously reported. Leukemia (SMR = 1.3; 95% CI = 0.6-2.4) and multiple myeloma (SMR = 1.2; 95% CI = 0.3-2.9) rates were at expected levels among maintenance workers with intermittent high exposure to benzene. These findings provide evidence on both sides of the debate about whether low benzene exposure increases the risk of multiple myeloma and all types of leukemia.

Evaluation of lymphopenia among workers with low-level benzene exposure and the utility of routine data collection.

Whether low-level benzene exposure produces health effects is controversial. We used routinely collected data from our medical/industrial hygiene system to study 387 workers with daily 8-hour time-weighted exposures averaging 0.55 ppm. The cross-sectional repeated survey design included 553 unexposed workers. Lymphopenia is considered to be the earliest and most sensitive indicator of benzene toxicity. We found no increase in the prevalence of lymphopenia among benzene-exposed workers (odds ratio, 0.6; 95% confidence interval, 0.2 to 1.8), taking into account smoking, age, and sex. There also was no increase in risk among workers exposed 5 or more years (odds ratio, 0.6; 95% confidence interval, 0.2 to 1.9). Examination of other measures of hematotoxicity, including mean corpuscular volume and counts of total white blood cells, red blood cells, hemoglobin, and platelets, produced similar results. We conclude that risk of lymphopenia and other early indicators of hematotoxicity are not increased among workers in this study who were exposed to low levels of benzene.

Evaluation of mortality and cancer incidence among alachlor manufacturing workers.

Alachlor is the active ingredient in a family of preemergence herbicides. We assessed mortality rates from 1968 to 1993 and cancer incidence rates from 1969 to 1993 for manufacturing workers with potential alachlor exposure. For workers judged to have high alachlor exposure, mortality from all causes combined was lower than expected [23 observed, standardized mortality ratio (SMR) = 0.7, 95% CI, 0.4-1.0], cancer mortality was similar to expected (6 observed, SMR = 0.7, 95% CI, 0.3-1.6), and there were no cancer deaths among workers with 5 or more years high exposure and 15 or more years since first exposure (2.3 expected, SMR = 0, 95% CI, 0-1.6). Cancer incidence for workers with high exposure potential was similar to the state rate [18 observed, standardized incidence ratio (SIR) = 1.2, 95% CI, 0.7-2.0], especially for workers exposed for 5 or more years and with at least 15 years since first exposure (4 observed, SIR = 1.0, 95% CI, 0.3-2.7). The most common cancer for these latter workers was colorectal cancer (2 observed, SIR 3.9, 95% CI, 0.5-14.2 among workers). Despite the limitations of this study with respect to small size and exposure estimating, the findings are useful for evaluating potential alachlor-related health risks because past manufacturing exposures greatly exceeded those characteristic of agricultural operations. These findings suggest no appreciable effect of alachlor exposure on worker mortality or cancer incidence rates during the study period.

Evaluation of ocular health among alachlor manufacturing workers.

Earlier toxicology studies found that one strain of rat (Long-Evans) developed severe ocular lesions when fed high doses of alachlor, a chloracetanilide active ingredient in some preemergent herbicides used for corn, soybean, and peanut crops. Because of a lack of eye effects in feeding studies conducted in dogs and other rodent species and strains, the effect was believed to be specific to Long-Evans rats. Nevertheless, to determine whether there were ocular effects among alachlor-exposed workers, we examined a group of the highest exposed alachlor production workers (n = 135) for the presence of a specific eye abnormality, analogous to the initiating lesion in Long-Evans rats, called pigmentary dispersion syndrome. A similar examination was given to unexposed coworkers and relatives (n = 84) to provide comparison rates. None of the exposed workers were found to have pigmentary dispersion syndrome, and prevalence rates for other eye abnormalities were similar for exposed and unexposed study participants. These results suggest that humans exposed to alachlor are not at increased risk of developing ocular disease.

The search for causes of idiopathic intracranial hypertension. A preliminary case-control study.

Idiopathic intracranial hypertension (pseudotumor cerebri) is a condition that occurs predominantly in obese women. It consists of elevated spinal fluid pressure, normal spinal fluid contents, papilledema, and headaches with normal imaging studies. Long lists of putative causes and associations have arisen, many consisting of individual case reports. We did a retrospective case-control study on 40 patients and 39 age- and sex-matched control subjects to examine the incidence of these associated conditions. Our results are only suggestive due to the small sample size; however, obesity and recent weight gain occurred more commonly in patients with idiopathic intracranial hypertension than in control subjects. All forms of menstrual abnormalities, incidence of pregnancy, antibiotic use, and oral contraceptive use were equal in both groups. A larger multicenter study will be needed to more completely characterize the risk factors for this condition.

Cancer in Alaskan Indians, Eskimos, and Aleuts, 1969-83: implications for etiology and control.

The authors collected and analyzed cancer incidence data for Alaska Natives (Indians, Eskimos, and Aleuts) for the 15-year period 1969-83 by ethnic and linguistic groups. Compared with U.S. whites, observed-to-expected ratios are high in more than one ethnic group for cancer of the nasopharynx, salivary gland, liver, gallbladder, and cervix. Low ratios were found for cancer of the breast, uterus, bladder, and melanoma. In Alaska, Eskimos have the highest risk for cancer of the esophagus and liver and the lowest risk for breast and prostate cancer. Risk for multiple myeloma in Indian men in Alaska exceeds not only those of other Native groups in Alaska but that in U.S. whites as well. Despite the short period studied, increases in cancer incidence over time can be documented for lung cancer in Eskimo men and women combined, and for cervical cancer, especially in Indian women.

Increased risk of cancer in siblings of Alaskan native patients with nasopharyngeal carcinoma.

Alaskan Natives (Eskimos, Indians, Aleuts) are at increased risk of developing nasopharyngeal cancer (NPC) and there is family clustering of NPC. This study reviewed the total cancer experience of relatives of NPC patients and found that siblings of Eskimo NPC patients had a nearly threefold risk. No cancer family syndrome was identified and the cancers diagnosed in the siblings were similar to those seen in the general Alaskan Eskimo population.