Lung cancer mortality among workers in the European production of man-made mineral fibers--a Poisson regression analysis

One hundred and eighty-one lung cancer deaths among workers during 301,085 person-years in European man-made mineral fiber production between 1930-1955 and 1982 were analyzed according to Poisson regression models including age, calendar period, country, and exposure variables. Time since first employment was the variable most strongly associated with lung cancer risk in both the rock-slag wool and glass wool subcohorts. Workers in the early technological phase were at higher risk than those in other categories, particularly in rock-slag wool production. No clear trend with duration of employment was suggested. No major changes occurred in the interpretation of the results when workers with less than one year of employment or less than 20 years since first exposure were excluded. The original results, based on analyses for standardized mortality ratios, were confirmed, and workers with a short duration of employment or a short time since first employment did not need to be excluded from the analysis.

Incidence of cancer in Norwegian workers potentially exposed to electromagnetic fields

The risk of cancer was investigated in a cohort of 37,945 male Norwegian electrical workers for whom information on job description was collected from 1960 census data and linked to the 1970 census data. The standardized incidence ratio was calculated for all cancer sites in the overall cohort by comparison with national incidence rates for economically active men at the 1960 census. The standardized incidence ratios for cancers of the breast, pleura (mesothelioma), larynx, and bladder and for soft tissue sarcoma were elevated, while those for non-Hodgkins and Hodgkins lymphoma were lower. The standardized incidence ratio for leukemia for electrical workers with 10 or more economically active years was 1.41. The standardized incidence ratio for brain tumors in this subgroup of electrical workers was 1.14. These results from a large, national, population-based study at the Cancer Registry of Norway give support to previous findings of a possible association between electrical work and the risk of leukemia.

Cancer incidence among creosote-exposed workers

Cancer incidence was studied among 922 creosote-exposed impregnators at 13 plants in Sweden and Norway. The subjects had been impregnating wood (eg, railroad cross-ties and telegraph poles), but no data on individual exposures were available. The study population was restricted to men employed during the period 1950-1975, and their cancer morbidity was checked through the cancer registries. The total cancer incidence was somewhat lower than expected, 129 cases versus 137 expected [standardized incidence ratio (SIR) 0.94]. Increased risks in both countries combined were observed for lip cancer (SIR 2.50, 95% confidence interval (95% CI) 0.81-5.83), skin cancer (SIR 2.37, 95% CI 1.08-4.50), and malignant lymphoma (SIR 1.9, 95% CI 0.83-3.78). Exposure to sunlight may have contributed to the risk of lip and skin cancer. The small number of cancer cases does not permit valid conclusions. The findings indicate that impregnating wood with creosote in earlier decades increased the risk of skin cancer.

A cohort study on cancer incidence in offspring of male printing workers

We used multistep register linkage to measure the occurrence of cancer in offspring of male members of the Oslo unions of printers. A file of their children was established through linkage with the Central Population Register. Children born 1950-1987 (N = 12,440) were traced for cancer during 1965-1987 in the Cancer Registry of Norway (193,406 person-years). We found 33 cases of cancer. The standardized incidence ratio was near expected for person-years after age 14 (25 cases observed) but lower than expected for person-years in the age group 0-14 years (eight cases observed, standardized incidence ratio 0.58, 95% confidence interval 0.25-1.14). This negative association was stronger when more precise criteria for time of exposure were applied, especially for children 0-14 years with fathers in categories exposed to lead 1 year before the child's birth. Methodologic problems with this approach are nondifferential exposure misclassification and the need for large data sets. The method could serve as an alternative to the case-control design in reproductive epidemiology.

Delayed gastrointestinal transit times in anorexia nervosa and bulimia nervosa

Anorectic and bulimic patients frequently report symptoms of constipation, bloating, and abdominal pain suggestive of abnormal gastrointestinal motility or transit. However, except for studies of gastric emptying, gastrointestinal motility and transit in these eating disorders have not been investigated. Ten anorectic and 18 bulimic inpatients were compared with 10 healthy controls. Whole-gut transit was tested by the radiopaque marker technique, and mouth-to-cecum transit time was assessed by the lactulose breath test. All anorectics and 67% of bulimics complained of constipation. Whole-gut transit time was significantly delayed in both anorectics (66.6 +/- 29.6 hours) and bulimics (70.2 +/- 32.4 hours) compared with controls (38.0 +/- 19.6 hours). Mouth-to-cecum transit time also tended to be longer in anorectics (109.0 +/- 33.5 minutes) and bulimics (106.2 +/- 24.5 minutes) than in controls (84.0 +/- 27.7 minutes), but these differences were not statistically significant. Delayed transit could contribute to or perpetuate the eating disorders by (a) causing the patient to feel bloated, thereby exacerbating fear of fatness, or (b) causing rectal distention, which may reflexly inhibit gastric emptying.

Nutritional value of yeast for Dermatophagoides pteronyssinus (Acari: Epidermoptidae) and the antigenic and allergenic composition of extracts during extended culturing

Cultures of European house dust mite, Dermatophagoides pteronyssinus (Trouessart), were evaluated with respect to yeast nutritional value, together with an assessment of the antigenic and allergenic composition. CIE analysis of extracts illustrated that yeast contributes many antigens throughout the rearing period. However, there is an indication of the consumption of only one particular yeast antigen by the mites. Total protein content profile of the mite cultures is shown in addition to the total allergen activity (RAST determinations). The allergenic activity of the extracts steadily increased during the mite culturing period; this may be due to the accumulation of fecal particles containing the major allergen.

A collaborative study of cancer incidence and mortality among vinyl chloride workers

A large European multicentric cohort study has been coordinated by the International Agency for Research on Cancer with the objectives of investigating the dose-response relationship between liver cancer and exposure to vinyl chloride and assessing cancer risk for sites other than the liver. A nearly threefold increase in liver cancer was detected on the basis of 24 observed deaths and 8.4 expected (standardized mortality ratio 286, 95% confidence interval 186-425). The excess from liver cancer was clearly related to time since first exposure, duration of employment, and estimated ranked and quantitative exposures. Other cancer sites investigated on the basis of a priori hypotheses were either not in excess (lung) or apparently unrelated to the exposure variables (brain and lymphoma).

The risk of cancer at all sites following gastric operation for benign disease. A cohort study of 4,224 patients

This report represents the results of a historical cohort analysis of 3,360 males and 864 females who had a gastric resection or gastroenterostomy for benign disease between 1990 and 1969. Within the period 1970 to 1988 the cohort was cross-checked with the data files at the Cancer Registry of Norway to identify the patients in whom cancer had been diagnosed. When analyzed according to cancer sites, increased risk was recorded for the oropharynx, stomach, colon, pancreas, liver, biliary tract, larynx, lungs, urinary bladder and non--melanomatous cancers of the skin in males. In females, increased risk was only observed for the oropharynx, but was close to a statistically significant level also for cancer of the stomach. A lower number of tumors of the central nervous system than expected was observed in both males and females. The increased risk of cancer of the lungs, larynx and urinary bladder in males can be regarded as evidence of the high prevalence of smokers in the cohort. We suggest that the increased risk of cancer of digestive organs is mainly related to life-style factors, particularly tobacco-specific nitrosamines whose effect is enhanced by surgical sequelae.

A historical prospective study of European stainless steel, mild steel, and shipyard welders

A multicentre cohort of 11,092 male welders from 135 companies located in nine European countries has been assembled with the aim of investigating the relation of potential cancer risk, lung cancer in particular, with occupational exposure. The observation period and the criteria for inclusion of welders varied from country to country. Follow up was successful for 96.9% of the cohort and observed numbers of deaths (and for some countries incident cancer cases) were compared with expected numbers calculated from national reference rates. Mortality and cancer incidence ratios were analysed by cause category, time since first exposure, duration of employment, and estimated cumulative dose to total fumes, chromium (Cr), Cr VI, and nickel (Ni). Overall a statistically significant excess was reported for mortality from lung cancer (116 observed v 86.81 expected deaths, SMR = 134). When analysed by type of welding an increasing pattern with time since first exposure was present for both mild steel and stainless steel welders, which was more noticeable for the subcohort of predominantly stainless steel welders. No clear relation was apparent between mortality from lung cancer and duration of exposure to or estimated cumulative dose of Ni or Cr. Whereas the patterns of lung cancer mortality in these results suggest that the risk of lung cancer is higher for stainless steel than mild steel welders the different level of risk for these two categories of welding exposure cannot be quantified with precision. The report of five deaths from pleural mesothelioma unrelated to the type of welding draws attention to the risk of exposure to asbestos in welding activities.

Trends in mesothelioma incidence in Norway 1960-1988

The age and sex related trends in incidence of malignant mesothelioma and trends in notification of mesothelioma to the Labour Inspection between 1960-88 are investigated. For men, the age-adjusted incidence rate increased from 0.4 per 100,000 in the period 1960-69 to 1.4 per 100,000 in the period 1980-88. The number of mesotheliomas notified to the Labour Inspection increased from only 4 in the period 1960-69 to 165 in the period 1980-88. The incidence rate among women was unchanged, about 0.1 per 100,000.

Cancer incidence among asbestos-exposed chemical industry workers: an extended observation period

A previous study on the incidence of cancer in a cohort of 286 asbestos-exposed electrochemical industry workers observed from 1953 through 1980 has been extended with another 8 years of follow-up. The incidence of cancer was derived from the Cancer Registry of Norway, and the expected figures were calculated by a life table method. During the extended follow-up period from 1981 through 1988, among the cohort members there were 12 new cancer cases versus 14.2 expected (SIR 85, 95% CI 44-158). In a lightly exposed sub-cohort, the extended follow-up revealed 4 cases of lung cancer or pleural mesothelioma (ICD, 7th revision 162-163) versus 1.6 cases expected (SIR 256, 95% CI71-654). In a heavily exposed sub-cohort, the corresponding figures were 3 and 0.5 (SIR 588, 95% CI 118-1,725).

Long-term observation of the detrusor smooth muscle in rats. Its relationship to ovariectomy and estrogen treatment

We studied the bladders of 24-month-old intact rats, rats that had been ovariectomized at the age of 6 months, and intact and ovariectomized rats treated by estrogen from the age of 16 months. The study thus comprized four groups: group I: bilaterally ovariectomized rats; group II: intact rats; group III: ovariectomized rats treated with estrogen; group IV: intact rats treated with estrogen. The weight and collagen concentration of the bladders were determined. The ovariectomized bladders weighed significantly less and had a higher collagen concentration than the intact bladders. Estrogen substitution for ovariectomized rats reversed these parameters. Detrusor strips were also used for organ bath studies. All bladders were similar in regard to the nerve-mediated frequency-response relationship. The atropine-resistant response was studied by adding scopolamine to the organ bath. Strips from ovariectomized rats had a significantly diminished atropine-resistant response, which was abolished by estrogen substitution. The present study suggests that micturition problems in menopause might have a structural as well as a pharmacological explanation.

High-performance liquid chromatographic determination of levomepromazine (methotrimeprazine) and its main metabolites in serum and urine

A new analytical method has been developed for simultaneous quantitation of levomepromazine and its five main metabolites in serum and urine. The method uses C-2 bonded phase extraction and reversed-phase high-performance liquid chromatography, based on ion-pair formation with dodecyl sulfate. The detection limits were 15 nM for levomepromazine and N-desmethyl levomepromazine, 28 nM for levomepromazine sulfoxide, and 56 nM for 3-hydroxylevomepromazine. 7-hydroxylevomepromazine, and O-desmethyllevomepromazine in serum, and lower in urine. The method was applied to measure steady-state serum and urine concentrations of levomepromazine and metabolites in five psychiatric patients. The concentrations of levomepromazine sulfoxide and N-desmethyllevomepromazine were generally higher than the concentrations of levomepromazine. The hydroxylated and O-demethylated metabolites were also found in higher concentrations than levomepromazine, but mainly as conjugates.

Nimodipine enhances new learning after hippocampal damage

Rats were trained to lever press and then were given either bilateral lesions of the hippocampus or control operations. Half of the rats in each group received oral nimodipine, a calcium entry blocker, while the remaining rats received vehicle, over a 14-day period that began the evening of surgery. The rats were studied on a DRL 20-s schedule of reinforcement (differential reinforcement of low rates of responding) that required them to withhold a response for at least 20 s after their last lever press in order to earn a reward. Rats with lesions that did not receive the drug performed poorly on the DRL 20-s schedule. In contrast, rats sustaining the same hippocampal lesions but given the drug showed scores that were virtually equivalent to those of the sham-operated control animals. Similar trends were observed when the rats were then tested on a DRL 40-s schedule of reinforcement. These findings suggest that nimodipine may attenuate the effects of acute, focal brain lesions on new learning of even difficult behavioral and cognitive tasks.

Protective effect of polyclonal and monoclonal antibodies against abortion in mice infected by Chlamydia psittaci

The role of antibody in preventing placental and fetal infection by Chlamydia psittaci was studied in mice. Pregnant mice were passively immunized with polyclonal sera or monoclonal antibodies (mAbs) at day 11 of gestation. The mice were intravenously challenged the following day with the virulent AB7 ovine abortion strain of C. psittaci. Mice were either killed on day 16 of gestation to determine placental and fetal chlamydial infection levels or were permitted to have and raise their young until 8 days old for comparison of survival rates. Immune sera produced a decrease in both placental and fetal infection and reduced the number of young dying in utero or shortly after birth. Polyclonal sera to the highly invasive AB7 and AB4 strains or to the invasive 1B strain were more effective than serum to the invasive AB13 strain. The B577/F3 and B577/A11 monoclonal antibodies gave almost complete protection, with only low levels of placental infection and no detectable fetal infection or decrease in survival rate. The study demonstrates that immune sera and type-specific mAbs can passively transfer resistance to placental and fetal colonization and to abortion and fetal loss in mice intravenously challenged with P. psittaci.

Comparison of one dose versus three doses of prophylactic antibiotics, and the influence of blood transfusion, on infectious complications in acute and elective colorectal surgery

In a randomized prospective controlled trial involving 311 patients undergoing acute or elective colorectal surgery, the efficacy and safety of two different single dose and one triple dose regimen of antibiotic prophylaxis, as well as the influence of blood transfusion on postoperative infectious complications, were studied. Postoperative infectious complications occurred in a total of 59 patients (19.0 per cent). There were no major differences between the three treatment groups. Thirty-four patients (10.9 per cent) developed abdominal wound infection, 17 patients (5.5 per cent) intra-abdominal abscess and 16 patients (5.1 per cent) anastomotic leakage. Of 202 patients (65.0 per cent) requiring blood transfusion during hospitalization 57 (28.2 per cent; 95 per cent confidence limits of 23-36 per cent) developed infectious complications, whereas two non-transfused patients (1.8 per cent; 95 per cent confidence limits of 0.2 to 6 per cent; P less than 0.001) developed infectious complications. It is concluded that one single dose of antibiotic prophylaxis in acute and elective colorectal surgery is as protective as a triple dose regimen. The development of infectious complications despite antibiotic prophylaxis is strongly related to blood transfusion.

Second non-germ cell malignancies after radiotherapy of testicular cancer with or without chemotherapy

The incidence of a new primary non-germ cell malignancy was determined in 876 patients with testicular cancer treated at the Norwegian Radium Hospital from 1956 to 1977. Sixty-five patients developed a second cancer leading to a statistically significant increased relative risk (RR = 1.58), especially if extended radiotherapy had been given (RR = 4.13). The excess risks of developing lung cancer and malignant melanoma were 2.03 and 3.89, respectively. Increased RR for these two cancer types were seen both after extended radiotherapy and after radiotherapy combined with chemotherapy. Studies of the time between treatment and secondary lung cancer indicated that the development of the new lung cancer could be partly treatment related, whereas the raised incidence of malignant melanoma may be related to the frequent health checks performed in patients with testicular cancer. Patients who had received extended radiotherapy were also at an increased risk of developing cancer of the stomach and of the colon. Three cases of acute leukaemia were observed more than 5 years after treatment, all of them in patients who had received abdominal radiotherapy only. It is concluded that patients apparently cured of a testicular cancer have an increased risk of developing a new treatment related non-germ cell malignancy, in particular lung cancer. The application of the extended radiotherapy or the combination of radiotherapy and chemotherapy containing alkylating drugs should be avoided in order to reduce this excess risk.

Risk for cancer of the urinary bladder among hairdressers in the Nordic countries

Several studies have indicated an increased risk for cancer of the urinary bladder among hairdressers. In a Danish linkage between census data and cancer register data both male and female hairdressers have an elevated risk for bladder cancer. The risk for lung cancer is close to unity, indicating that occupational factors rather than smoking, may be responsible for the increased risk for bladder cancer among hairdressers. To evaluate this hypothesis we conducted a collaborative analysis of data from similar linkages in Finland, Norway, and Sweden. The combination of high risk for bladder cancer and low or no risk for lung cancer was not found in the other Nordic countries; however, statistically significant increased risks for both bladder and lung cancer were found among male hairdressers in both Norway and Sweden. The relative risks for bladder cancer were of the same magnitude as the relative risks for lung cancer.