Thapsigargin analogues for targeting programmed death of androgen-independent prostate cancer cells

A number of analogues of thapsigargin, a selective inhibitor of the sarco-endoplasmic reticulum Ca2+-ATPases have been synthesized. In all of the prepared analogues the butanoyl residue at O-8 has been replaced with a residue containing an aromatic amine. The amine can be used as an anchoring point for attaching a peptide group sensitive to the proteolytic enzyme, prostate specific antigen, secreted by prostate cancer cells. Like thapsigargin, the analogues are capable of elevating the cytoplasmic Ca2+ concentration approximately sevenfold when tested at effective cytotoxic doses. The analogues in which the 8-O-butanoyl group has been replaced with 3-(4-aminophenyl)propanoyl or 4-aminocinnamoyl were found potently to induce programmed cell death of the prostate cancer cells.

Incidence of breast cancer in a Norwegian cohort of women with potential workplace exposure to 50 Hz magnetic fields

BACKGROUND

The risk of breast cancer was investigated in a large dynamic population-based cohort of all 1.1 million economically active women in Norway with potential exposure to 50 Hz magnetic fields at the censuses of 1960, 1970, and 1980.

METHODS

The follow-up period for the cohort was 1961-1992. For each woman, date of birth and census information on occupation and socioeconomic status were ascertained. These data were linked to the breast cancer morbidity information in the Cancer Registry of Norway. Exposure to magnetic fields was assessed a priori using two different approaches. In the first approach, hours per week in a potential magnetic field above background level (0.1 microT) were classified by an expert panel. In the second approach, measured magnetic fields from a separate study of men at work were allocated to the women's census job titles. In both approaches, exposure was cumulated over the years of employment (work hours and microT-years, respectively).

RESULTS

The Poisson regression analysis showed a risk ratio (RR) of 1.14 (95% confidence interval (CI) = 1.10-1.19) in the highest exposure category compared to the lowest when using the first approach, and the corresponding RR was 1.08 (95% CI = 1.01-1.16) when using the second approach. For women younger than 50 years, RR was 1.20 (95% CI = 1.11-1.29) and 1.12 (95% CI = 0.98-1.28), respectively.

CONCLUSIONS

The results give some support to the hypothesis that exposure to 50 Hz magnetic fields may increase the risk of breast cancer. However, since no direct information on exposure was available, no firm conclusions can be drawn.

Epstein-Barr virus and cytomegalovirus in relation to testicular-cancer risk: a nested case-control study

An infectious etiology of testicular cancer has been suggested. We have evaluated seroreactivity against cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in relation to testicular-cancer risk in a case-control study, nested within a cohort of prospectively collected serum specimens from 293,692 individuals. For each of 81 cases of testicular cancer identified, 3 controls were randomly selected from the cohort. Serum IgG antibody titers against CMV and EBV were determined using enzyme-linked immunosorbent assays (ELISAs) and immunofluorescence methods. Odds ratios (OR) were obtained from conditional logistic-regression models. No association was found between CMV positivity and testicular cancer overall (OR = 1.08; 95% confidence interval 0.60-1.94); risk for testicular seminoma was increased among CMV seropositive [OR = 1.70 (0.80-3.59)], whereas seropositivity was associated with decreased risk for testicular non-seminoma [OR = 0.54 (0.19-1.56)] (p for heterogeneity, 0.09). For EBV, the risk for testicular cancer was increased among individuals seropositive for viral capsid antigen (VCA) [OR = 2.74 (0.62-12.12)]. The results lend some support to the hypothesis of an infectious etiology, and we propose that future studies should take into account age at infection.

The quality of psychiatric residency : the assessment of programs and options for distributing psychiatric residents in the service of health care reform

Recent health care reform initiatives proposed training fewer medical specialists, including psychiatrists, and determining the size and location of training programs via centralized regulatory mechanisms. Facing such potential future developments, the American Association of Directors of Psychiatric Residency Training appointed a Task Force on the Quality of Residency Programs to develop informed recommendations for the field. This paper describes the Task Force's considerations and recommendations concerning how the least damaging and most effective decisions could be made regarding the distribution of residency positions, program size, and the future funding of training stipends. The recommendations emphasize voluntary decisions, feedback from local and regional stakeholders regarding perceived needs and demands for psychiatrists, and Federal or regional funding of postgraduate training stipends that are not primarily tied to providing clinical services.

Cancer incidence among European man-made vitreous fiber production workers

OBJECTIVES

This study analyzed cancer incidence among man-made vitreous fiber workers.

METHODS

A cancer incidence follow-up was conducted among 3685 rock-slag wool (RSW) and 2611 glass wool (GW) production workers employed for > or =1 year in Denmark, Finland, Norway, or Sweden, and the standardized incidence ratios (SIR) were calculated on the basis of national incidence rates.

RESULTS

Overall cancer incidence was close to expectation. Lung cancer incidence was increased among the RSW [SIR 1.08, 95% confidence interval (95% CI) 0.85-1.36] and GW (SIR 1.28, 95% CI 0.91-1.74) workers. For both subcohorts, a trend was suggested for time since first employment (P-value for linear trend 0.1 and 0.2, respectively). Neither subcohort showed an association with employment during the early technological phase, when fiber exposure was high. The incidence of oral, pharyngeal, and laryngeal cancer was increased among the RSW (SIR 1.46, 95% CI 0.99-2.07) and the GW (SIR 1.41, 95% CI 0.80-2.28) subcohorts. Despite a trend in risk for these neoplasms among the GW workers with time since first employment, the lack of a positive relation with other indirect indicators of fiber exposure points against a causal interpretation. No association between RSW or GW exposure and the risk of other neoplasms was suggested.

CONCLUSIONS

These lung cancer results are similar to those of a mortality study that included a larger number of factories. For other cancers there was no suggestion of an association with RSW or GW exposure.

Occupational exposure and cancer incidence among workers from an aluminum smelter in western Norway

OBJECTIVES

This study investigated the associations between specific cancers and occupational exposure to polycyclic aromatic hydrocarbons (PAH), asbestos, electromagnetic fields, and heat in a cohort of workers from a Norwegian aluminum smelter.

METHODS

Cancer incidence between 1953 and 1993 was observed for 2647 male short-term workers and 2 cohorts of men with at least 4 years' employment (2888 production workers and 373 maintenance workers). Standardized incidence ratios (SIR) were calculated from the national male cancer incidence, and associations with cumulative exposure were investigated by stratified analysis. Cumulative exposure in 15-year time windows was used as an alternative dose indicator.

RESULTS

Investigation of the a priori hypotheses in the production cohort revealed a positive association between bladder cancer and PAH exposure 30 years or more before observation. The results also suggested an association between PAH and pancreatic cancer, although not statistically significant. No association was seen between exposure to PAH and cancers of the lungs or between magnetic field exposure and lymphatic and hematopoietic cancer. In the maintenance cohort there was a positive association between employment as an electrician and lymphatic and hematopoietic cancer and a statistically nonsignificant association between PAH and lung cancer. The short-term workers showed a statistically significant excess of lung cancer.

CONCLUSIONS

The results support previous findings of an association between exposure to PAH and bladder cancer.

Determination of mitotane (o,p-DDD) and its metabolites o,p-DDA and o,p-DDE in plasma by high-performance liquid chromatography

The adrenolytic agent mitotane (o,p'-DDD or 1,1-(o,p'-dichlorodiphenyl)-2,2-dichoroethane) is believed to be metabolically activated, resulting in the generation of reactive intermediates or the formation of o,p'-DDA. A new high-performance liquid chromatographic (HPLC) method for measurement of mitotane and two of its metabolites, o,p'-DDA (1,1-(o,p'-dichlorodiphenyl) acetic acid) and o,p'-DDE (1,1-(o,p'-dichlorodiphenyl)-2,2 dichloroethene), in plasma has been developed. Sample preparation involves precipitation of plasma proteins with acetone before chromatographic separation under isocratic conditions on a silica-based diphenyl column. Mitotane and metabolites are quantified by ultraviolet detection at 218 nm. Recoveries for the three compounds range between 99% and 110%, with between-day and within-day coefficients of variation <6% within the therapeutic range. Limits of detection are 0.5 microM and the assay is linear up to at least 800 microM for o,p'-DDA and 100 microM for mitotane and o,p'-DDE. The method has been evaluated using samples from three patients on mitotane therapy, revealing o,p'-DDA levels in plasma 3 to 10 times higher than the levels of the parent compound.

Systemic availability and pharmacokinetics of nebulised budesonide in preschool children

AIM

To evaluate the systemic availability and basic pharmacokinetic parameters of budesonide after nebulisation and intravenous administration in preschool children with chronic asthma.

METHODS

Plasma concentrations of budesonide were measured for three hours after an intravenous infusion of 125 micrograms budesonide. The children then inhaled a nominal dose of 1 mg budesonide through the mouthpiece of a Pari LC Jet Plus nebuliser connected to a Pari Master compressor, and the plasma concentrations of budesonide were measured for another six hours. The amount of budesonide inhaled by the patient ("dose to subject") was determined by subtracting from the amount of budesonide put into the nebuliser, the amount remaining in the nebuliser after nebulisation, the amount emitted to the ambient air (filter), and the amount found in the mouth rinsing water.

RESULTS

Ten patients aged 3 to 6 years completed both the intravenous and the inhaled treatment. The mean dose to subject was 23% of the nominal dose. The systemic availability of budesonide was estimated to be 6.1% of the nominal dose (95% confidence intervals (CI), 4.6% to 8.1%) or 26.3% of the dose to subject (95% CI, 20.3% to 34.1%). Budesonide clearance was 0.54 l/min (95% CI, 0.46 to 0.62), steady state volume of distribution 55 litres (95% CI, 45 to 68), and the terminal half life was 2.3 hours (95% CI, 2.0 to 2.6).

CONCLUSIONS

Approximately 6% of the nominal dose (26% of the dose to subject) reached the systemic circulation of young children after inhalation of nebulised budesonide. This is about half the systemic availability found in healthy adults using the same nebuliser.

Occupational exposure to chemical and biological agents in the nonproduction departments of pulp, paper, and paper product mills: an international study

As part of an international epidemiological study of workers in the pulp and paper industry, previously unpublished exposure measurements were assembled in a database. This article describes 7293 measurements in nonproduction departments from 147 mills in 11 countries. The greatest variety of agents was measured in the maintenance, construction, and cleaning department, where high exposures to asbestos, chromium [VI] compounds, copper, mercury in urine, nitrogen dioxide, ozone, styrene, sulfur dioxide, trichloroethylene, and welding fumes were observed. Measurements in the storage, yard, loading, and shipping department indicated high exposures to asbestos, carbon monoxide, fungal spores, nitrogen oxides, sulfur dioxide, and total dust. The steam and power generation department had high exposures to methyl mercaptan, silica, and total dust. Measurements in process and effluent water treatment, laboratory and research, engineering, and office, administration, and cafeteria areas had few elevated exposures. Throughout the nonproduction departments, measurements of pulp-production chemicals such as chlorine and sulfur compounds tended to be low, with many below detection limits. There were some problems with the available data; in particular, detection limits were often not specified, and the data tended to be clustered in such a way that sources of exposure variability could not be distinguished. Despite these problems, the data provide new insight into the exposures of nonproduction pulp and paper industry personnel.

Mortality of short-term workers in two international cohorts

The purpose of this study was to compare the pattern of mortality of blue-collar workers employed less and more than 1 year in the man-made vitreous fiber (MMVF) and the reinforced plastic industries, the latter group being exposed to styrene. We conducted an analysis among 21,784 workers with less than 1 year of employment (short-term workers) and 19,117 workers with 1 or more years of employment (long-term workers) employed in eight European countries. We conducted analyses based on external as well as internal comparisons. In both cohorts, the standardized mortality ratio for all causes among short-term workers was approximately 40% higher, compared with that for longer-term workers. In internal comparisons, the difference was reduced to 9% in the MMVF cohort and 11% in the styrene cohort. Workers with less than 1 month of employment displayed an increased mortality in both cohorts and in most countries. The increased mortality among short-term workers was not concentrated shortly after they quit employment. In both cohorts, short-term workers had a higher mortality from external causes, while little difference was seen in mortality from ischemic heart disease and malignant neoplasms. Although extra-occupational factors may contribute to increase the mortality of short-term workers and, in particular, of those employed for less than 1 month, the difference observed in analyses adjusted for characteristics of employment suggested a relatively small difference in mortality from most causes.

Lung cancer mortality among European rock/slag wool workers: exposure-response analysis

OBJECTIVES

The purpose was to analyze the relationship between semi-quantitative indices of exposure to manmade vitreous fibers and lung cancer mortality among European rock/slag wool (RSW) workers.

METHODS

The study population comprised 9,603 male workers employed in RSW production in seven factories in Denmark, Norway, Sweden, and Germany, followed up for mortality as of 1990-91. Estimates of past exposure to respirable fibers were used to calculate cumulative exposure with a 15-year lag and maximum annual exposure based on employment history up to 1977. Rate ratios were estimated via multivariate Poisson regression, adjusting for country, age, calendar year, time since first employment, and employment status.

RESULTS

A total of 159 lung cancer deaths were included in the analysis of which 97 among workers with more than one year of employment. We found nonstatistically significant trends in lung cancer risk according to cumulative exposure. Relative risks (RR) in the four quartiles were 1.0 (reference), 1.3 (95 percent confidence interval [CI] = 0.8-2.4), 1.2 (CI = 0.7-2.1), and 1.5 (CI = 0.7-3.0, P test for trend = 0.4). When workers with less than one year of employment were excluded, there was no increased risk; the RRs in the four quartiles were 1.0, 0.9 (CI = 0.4-2.0), 0.8 (CI = 0.3-1.9), and 1.0 (CI = 0.4-2.7). No trend was present according to maximum annual exposure. The results were not consistent among countries.

CONCLUSIONS

We found a positive association between exposure to respirable fibers and lung cancer mortality. However, the lack of statistical significance, the dependence of the results on inclusion of short-term workers, the lack of consistency among countries, and the possible correlation between exposure to respirable fibers and to other agents reduce the weight of such evidence.

Lung and bladder cancer in a Norwegian municipality with iron and steel producing industry: population based case-control studies

OBJECTIVES

To investigate the influence of occupation on the rising incidence of lung and bladder cancer among men in a Norwegian municipality where an iron and steel plant constituted the key industry between 1955 and 1989.

METHODS

Based on the lung cancer cases reported to the Cancer Registry of Norway from 1980 to 1992 a population based case-control study was performed, including 86 cases and 196 controls. Information on occupations and smoking habits was collected through interviews and from the personnel files from the industrial plants. A case-control study on bladder cancer with 52 cases and 156 controls was carried out to cast light on the role of polycyclic aromatic hydrocarbons (PAHs).

RESULTS

An odds ratio (OR) for lung cancer of 2.9 (95% confidence interval (95% CI) 1.2 to 6.7) was associated with exposure to PAHs. Based on data from personnel files, increased risk of lung cancer (OR 2.8 95% CI 1.1 to 7.0) was associated with work experience in the pig iron department at the ironworks. A non-significant OR of 1.8 was associated with exposure to asbestos. Bladder cancer was not associated with exposure to PAHs at the iron, steel, and coke plant, or with experience from any of the production departments at the plant.

CONCLUSIONS

One fifth of the lung cancer cases were attributed to exposure to PAHs or asbestos. More than 80% of the cases of lung cancer were attributed to tobacco smoking. The cancer risk in the pig iron department may be due to a combination of exposures to PAH, asbestos, or dust of mixed composition.

Incidence of lung cancer among shipyard welders investigated for siderosis

The incidence of lung cancer among 428 shipyard welders exposed for more than ten years to welding fumes was investigated. The welders were examined for siderosis by the Directorate of Labor Inspection in 1975. The present study was a follow-up based on historical information from the Norwegian registry of dust-exposed workers. Twenty-three welders with siderosis, and 156 welders working at the same shipyards as the siderosis cases were studied as sub-cohorts. There was no loss on follow-up. The observation period was 1976 through 1992. There were 32 cases of cancer from all causes vs 41.3 expected. A nonsignificant excess of lung cancer was observed; 10 cases vs 6.5 expected. The incidence of lung cancer was highest for the welders with more than 30 years since first exposure (7 cases vs 4.1 expected). The sub-cohort of welders with siderosis had no case of lung cancer vs 0.5 expected. These welders were assumed to have experienced high exposure levels for welding fumes. The morbidity of cancer from all causes was low for this small group of blue-collar workers, but the incidence of lung cancer was slightly increased. The increase was not attributable to welders with siderosis. Smoking and asbestos exposure are potential confounders.

Avoidable cancers in the Nordic countries. Alcohol consumption

Alcohol intake is causally associated with cancers of the larynx, oral cavity, pharynx, oesophagus and liver. In all five Nordic countries, alcohol consumption increased substantially between 1965 (6.5 litres per adult per year) and 1975 (10 litres), but remained at about 10 litres between 1975 and 1985. The daily consumption of men during the period was substantially higher than that of women, and that of both men and women was higher in Denmark than in the other Nordic countries. In about 2000, an annual total of almost 1,300 cancer cases (1,000 in men and 300 in women) would be avoided if alcohol drinking were eliminated. This corresponds to about 29% of all alcohol-related cancers, i.e. in the oesophagus (37%), oral cavity and pharynx (33%), larynx (29%) and liver (15%). About 2% of all cancers in men and 1% in women in the Nordic countries around the year 2000 will be caused by the drinking habits of the respective populations.

Avoidable cancers in the Nordic countries. Occupation

A number of chemicals encountered predominantly in occupational settings have been causally linked with cancer in humans; furthermore, several industrial processes and occupations have been associated convincingly with increased rates of cancer, although the specific carcinogens remain to be identified. The tissues affected are mainly the epithelial lining of the respiratory organs (nasal cavity, paranasal sinuses, larynx and lung), and urinary tract (renal parenchyma, renal pelvis and urinary bladder), the mesothelial linings, the bone marrow and the liver. During the period 1970-84, almost 4 million people (3.7 million men and 0.2 million women) in the Nordic countries were potentially exposed to above-average levels of one or more verified industrial carcinogens. It is expected that these exposures will result in a total of about 1,900 new cases of cancer every year in the Nordic countries around the year 2000, with 1,890 among men and fewer than 25 among women. The proportions that could be avoided if industrial carcinogens were eliminated would be 70% of mesotheliomas, 20% of cancers of the nasal cavity and sinuses, 12% of lung cancers, 5% of laryngeal cancers, 2% of urinary bladder cancers, 1% of the leukaemias, and 1% of renal cancers. Overall, it is estimated that verified industrial carcinogens will account for approximately 3% of all cancers in men and less than 0.1% of all cancers in women in the Nordic countries around the year 2000. No attempt was made to estimate the potential effects of suspected carcinogens in the workplace.

Avoidable cancers in the Nordic countries. External environment

Air pollutants arising from traffic clustering and industrial production include a number of chemical compounds that at high doses are carcinogenic in animal models and in some instances also in humans. Direct epidemiological evidence for a carcinogenic effect of air pollution in humans is, however, weak, and most of the available studies are limited by lack of adequate control of confounding factors and other methodological drawbacks. Limited evidence exists for a link between urban air pollution and lung cancer, with reported relative risks of 1.0-1.5. About one-third of the population of the Nordic countries, corresponding to 7.3 million people, lives in urban areas. If there is an excess risk associated with air pollution, the annual number of lung cancer cases around the year 2000 in the Nordic countries would range from 0 (no excess risk) to 1,800 (relative risk, 1.5). As the existence of a causal link between air pollution and cancer is not uncorroborated, measures for avoiding cancer from this source cannot be recommended.

Avoidable cancers in the Nordic countries. Tobacco smoking

Active smoking is causally associated with cancers of the lung, larynx, oral cavity, pharynx, oesophagus, pancreas, renal parenchyma, renal pelvis and urinary bladder, and passive smoking appears to be causally associated with cancer of the lung. Information on smoking habits for the years 1965, 1975 and 1985 shows that more men than women in the Nordic countries were current smokers. The rates of women were stable over time and those of men were decreasing, approaching those of women. Lung cancer, in particular, is strongly associated with active smoking: by increasing the number of cigarettes smoked per day (lifelong) to 5, 10, 20 and 40 or more, the risk increases by five-, eight-, 16- and 30-fold, respectively, over that of people who have never smoked. Thus, with approximately 35% current smokers and 25% former smokers among Nordic men in 1985 and approximately 30% current smokers and 15% former smokers among Nordic women in that year, by the year 2000 10,000 cases of lung cancer (6,500 in men and 3,500 in women) will be caused by active smoking; this is equivalent to 82% of all cases of lung cancer in these populations. Another 6,000 cancers of other types (4,000 in men and 2,000 in women) are caused annually by active smoking, yielding a total of 16,000 new cases each year around the turn of the century. This implies that 14% (19% in men and 9% in women) of all incident cancers in the Nordic countries around the year 2000 will be caused by active tobacco smoking. In comparison, passive smoking is a minor cause of lung cancer, responsible for approximately 0.6% of all new cases (approximately 70 cases annually) in this area around the turn of the century.

Summary of avoidable cancers in the Nordic countries

An overview is given of the most important known causes of cancer in the five Nordic countries and the resulting number of cancers that are potentially avoidable. The main causes include active and passive smoking, alcohol consumption, exposure to asbestos and other occupational carcinogens, solar and ionizing radiation, obesity, human papillomavirus infection in the female genital tract and infection with Helicobacter pylori. The organs most commonly affected are those of the respiratory system, the upper digestive tract and stomach, skin, the lower urinary tract and the uterine cervix. Annually, more than 18,000 cancers in men and 11,000 in women in the Nordic populations could be avoided by eliminating exposure to known carcinogens which is equivalent to 33% and 20% of all cancers arising in men and women, respectively, around the year 2000. Smoking habits account for a little more than half of these avoidable cases. Estimates of avoidable cancers are given for each Nordic country, separately.

Survival of breast cancer patients in Lithuania and Norway, 1988-1992

In Norway, the incidence of breast cancer is almost twice that in Lithuania, whereas the mortality rates of the disease are approximately the same in both countries. The aim of the present study was to compare the survival of breast cancer patients in the two countries according to stage. The material from both countries included cases diagnosed between 1988 and 1992 with complete follow-up of date of death to the end of 1995. The Norwegian data consisted of all 9403 new cases recorded by the Norwegian Cancer Registry. The Lithuanian data included in all 1649 new cases treated at the Oncology Centre in Vilnius, which represents 40% of breast cancer cases in Lithuania--these cases had the same distribution of the disease by age and stage as for the whole country. The overall 5-year relative survival was lower in Lithuania (57.3%) than in Norway (78.4%). Lower survival was observed in Lithuania compared with Norway for all stages. In stage I, the difference was 7.8% in absolute terms which could be explained by a higher proportion of small tumours among the Norwegian cancer cases (63.7% of tumours were 2 cm or less, while in Lithuania the proportion of small stage I tumours was only 27.9%). Therefore, early diagnosis within the stage I category seems relevant. The difference in survival was, however, most pronounced in stage II (20%) and III (29%). In Norway, the better overall survival is partly explained by a more favourable stage distribution. The lower survival of Lithuanian cases within stage categories could be explained by more advanced metastases to regional lymph nodes and by higher proportions of large tumours within stage.

The role of alcohol, tobacco, and dietary factors in upper aerogastric tract cancers: a prospective study of 10,900 Norwegian men

Previous knowledge on risk factors for oral, pharyngeal, laryngeal, and esophageal cancer has been based mainly on case-control studies. In the present study, the impact of alcohol consumption, tobacco smoking, and dietary factors on upper aerogastric tract cancer risk was studied in a cohort of 10,960 Norwegian men followed from 1968 through 1992, in which period a total of 71 upper aerogastric tract cancers occurred. The relative risk (RR) of cancer was 3.9 (95 percent confidence interval [CI] = 2.1-7.1) for the highest consumption group of alcohol and 4.7 (CI = 1.7-13.2) for the highest smoking level, compared with the respective reference groups. Among the dietary items, high consumption of oranges was associated with reduced cancer risk (RR = 0.5, CI = 0.3-1.0), as was high consumption of bread (RR = 0.2, CI = 0.1-0.5). Frequent consumption of beef and bacon increased relative cancer risk bordering on significance. The present results are largely in accordance with previous studies. The decreased risk associated with a high intake of bread deserves further investigation.

Intratumoral differences in methotrexate levels within human osteosarcoma xenografts studied by microdialysis

A central tenet in oncology is the assumed relationship between drug concentration and cytotoxicity. Determinations of drug levels in tumor tissues are, however, generally not undertaken. Microdialysis is a method where continuous drug monitoring may be achieved by sampling of low molecular weight substances from the extracellular space. By employing this technique it is possible to observe variable drug levels within tissues, including tumors, over time. Herein, we present results from a nude rat model where subcutaneous human osteosarcoma xenografts were established prior to the administration of the antifolate methotrexate as an intravenous infusion. Significant differences in drug exposure within single tumors were evident. Generally, peak drug concentrations were lower and drug efflux slower from the center of the tumors as compared to the periphery. The use of microdialysis could be an important tool for optimizing current strategies in anticancer chemotherapy.

Effects of 3-deazaadenosine on apoptosis-related gene transcripts in HL-60 cells

The effect of the transmethylation inhibitor 3-deazaadenosine on transcription levels of genes associated with apoptosis was investigated in HL-60 cells. After incubation of HL-60 cells with 100 microM 3-deazaadenosine for 45 min., a schedule known to perturb transmethylation metabolites and initiate apoptosis in these cells, a 50% decrease in c-myc and a 50% increase in bcl-2 RNA steady-state levels compared to control cells were observed. Transcription levels of c-myc continued to decrease after extended exposure to 3-deazaadenosine, while bcl-2 mRNA levels dropped to 25% and 30% below those in control cells after 1.5 hr and 3 hr, respectively. The expression levels of the bcl-2 related bax gene, showed a similar pattern as bcl-2; a 60% increase was initially measured, but after 1.5 and 3 hr, bax transcripts were 80% and 70% respectively, of those found in untreated cells. Another bcl-2 related gene, bcl-x, was previously reported to generate two transcripts in human cells. The long variant bcl-x1 acts as bcl-2, while the short form bcl-xs induces apoptosis. We were unable to detect bcl-xs transcripts in untreated and 3-deazaadenosine treated cells by the highly sensitive reverse transcriptase polymerase chain reaction method. This suggests that this gene product may not be involved in 3-deazaadenosine induced apoptosis in HL-60 cells. Bcl-x1 mRNA levels, however, slowly decreased with about 50% after 1.5 or 3 hr 3-deazaadenosine treatment. It is concluded that 3-deazaadenosine initiated apoptosis affects c-myc, bcl-2, bax and bcl-x1 mRNA levels.

Comparison of information on occupation and lifestyle habits obtained from European man-made vitreous fibre production workers and their relatives

BACKGROUND

Studies of the aetiology of fatal diseases often rely on data obtained from relatives, which can cause loss of precision and introduce bias. We assessed the quality of such information on demographics, occupation, smoking and alcohol habits.

METHODS

We compared contemporary interviews, based on a structured questionnaire, with male workers from the man-made vitreous fibre production industry in four European countries and their relatives. The participation rate was 63% (74 pairs of workers and relatives).

RESULTS

Only minor differences in the ability to answer the questions appeared among workers and relatives, except for specific occupational questions. There was moderate to excellent agreement for demographics, residential and work history (kappa or intraclass correlation range: 0.44-0.98). For smoking habits, beer and wine consumption the agreement was good to excellent (range: 0.59-0.99). In particular, number of different residential areas, jobs, industries, and duration of wine drinking were significantly underreported by the relatives. No general determinant for reduced agreement appeared.

CONCLUSIONS

In general, the quality of information obtained from relatives appeared good. However, information on specific occupational exposures may be improved by supplementing the information from relatives with details obtained from colleagues, occupational hygiene experts or occupation-exposure matrices.