Characterization of bladder tumours by multiparameter flow cytometry with special reference to grade II tumours.

Sixty-three human transitional cell carcinomas of the urinary bladder were studied by multiparameter flow cytometry (FCM). The cellular DNA content, the cellular protein content, the fraction of cells in S phase, and the nuclear size were registered and correlated to histological grade (WHO) and histologically determined infiltration through the basement membrane. Aneuploidy was found in the great majority of grade III tumours, but in only 24% of grade II tumours. A new, combined variable, viz. the cellular DNA to protein ratio, indicated a possibility for further subdivision of the tumours. Grade II tumours, which constitute a rather heterogeneous group with regard to prognosis, could be classified in two subgroups: One group of diploid tumours with the FCM characteristics of grade I tumours, and another group of diploid and aneuploid tumours with the characteristics of grade III tumours. Infiltration was most frequently seen in the latter subgroup. The putative prognostic relevance of such a subdivision will be the subject of a future study. Compared to FCM measurement of DNA alone, multiparameter FCM, including measurement of the total cellular protein content, has given additional information that may be of prognostic value.

Cancer incidence among Norwegian airline cabin attendants.

BACKGROUND: Cabin crews are exposed to cosmic radiation at work and this may increase their incidence of radiation-induced cancers. Former studies indicate an increased risk of breast cancer. METHODS: A retrospective cohort study was performed. The cohort was established from the files of the Civil Aviation Administration and included people with a valid licence as a cabin attendant between 1950 and 1994. The cohort was linked to the Cancer Registry of Norway. Observed number of cases was compared with expected, based on national rates. Breast cancer incidence was analysed, adjusting for individual fertility variables. RESULTS: A group of 3693 cabin attendants were followed over 72 804 person-years. Among the women, 38 cases of breast cancer were observed (standardized incidence ratio (SIR) = 1.1, 95% CI : 0.8-1.5). Among men excess risks were found for cancers in the upper respiratory and gastric tract (SIR = 6.0, 95% CI : 2.7-11.4) and cancer of the liver (two cases, SIR = 10.8, 95% CI : 1.3-39.2). For both sexes elevated risks were found for malignant melanoma and non-melanoma skin cancer; for men these were SIR = 2.9 (95% CI : 1.1-6.4) and SIR = 9.9 (95% CI : 4.5-18.8) respectively, while for women these were SIR = 1.7 (95% CI : 1.0-2.7) and SIR = 2.9 (95% CI : 1.0-6.9) respectively. For no cancer site was a significant decreased risk found. CONCLUSIONS: An increased risk of radiation-induced cancers was not observed. The excess risks of some other cancers are more probably explained by factors related to lifestyle.

Pregnancy outcome in Norway after Chernobyl.

Pregnancy outcome has been studied in terms of legal abortions, early spontaneous abortions and total number of pregnancies (in an ad hoc study covering 6 counties) as well as various perinatal health problems (on the basis of routinely recorded data for epidemiological surveillance from the Medical Birth Registry of Norway). Apparently, no effects were observed in terms of an increased occurrence of legal abortions, while spontaneous abortions increased from 7.2% of all pregnancies during the last 12 months before the accident to 8.3% after the accident [corrected]. At the same time, the total number of pregnancies somewhat decreased. Based on monthly measurements in each municipality of external and internal (food-based) doses, dose-response associations were assessed for a number of perinatal health problems. No associations were observed.

PIP: The effects of Chernobyl on pregnancy outcome were investigated in Norway in terms of legal abortions, early spontaneous abortions, total pregnancies, and perinatal health problems (cataracts, microcephaly, low birth weight, and perinatal mortality). The epidemiological results showed that there were no serious gross changes in pregnancy outcome in Norway after Chernobyl in 1986. Anxiety may have led to the temporary decrease in pregnancies. The statistically significant difference in spontaneous abortions between 19867 and 1987, particularly in the months following Chernobyl, may be related but causation cannot be determined based on the present data; i.e., dietary changes due to anxiety may also be related. Further analyses will be conducted with data spanning 5 years after Chernobyl. The Central Bureau of Statistics provided data on legal abortions as reported by hospitals to county medical officers. Spontaneous abortions (16 weeks) are based on ad hoc notifications from hospitals in 5 counties: Aust-Agder, Hordaland, Oppland, Troms, and Trondelag. Compulsory notification of births is recorded in the Medial birth Registry and includes congenital malformations and other perinatal health problems. The National Institute of Radiation Hygiene recorded data after the accident on indoor gamma rates, radiocesium (Cs 134) soil samples, and municipality specific average food-based dose equivalents of Cs 134 and 137 in meat and meat supplies. The total external and internal dose is provided for May 1986-April 1989. Food-based doses remained at an elevated level for an extended period of time. Infant exposure was considered form the 2nd month of gestation. Legal abortions, induced or spontaneous, were not impacted by Chernobyl, but the effect may have been delayed to the 3rd or 4th quarter with a 1.0% increase. However, at Haukeland Hospital in Bergen, the highest abortion rates were 19.1% in 1985-86 and 19.2% in 1986-87. Pregnancies temporarily decreased in the 3rd and 4th quarters following the accident in a period usually reflecting annual increases. Cataract occurrences increased the year after the accident with 8 observed and 3.8 expected, but the P value was insignificant (P=.74). Microcephaly followed a similar pattern. Birth 2500 gms had observed values of 2726 vs. 2639.2 expected, an insignificant P value of .99. Observed perinatal deaths of 634 were less than the 718.8 expected.

Chromosome analysis of peripheral lymphocytes from persons exposed to radioactive fallout in Norway from the Chernobyl accident.

Chromosome analysis of peripheral lymphocytes from two Norwegian populations (44 reindeer herding South samis from Røros and Snåsa, 12 sheep farmers from Valdres) exposed to fallout from the Chernobyl accident were made. The doses from caesium through the years 1987-1991 were calculated based on whole-body measurements 134Cs and 137Cs giving a total cumulative mean internal dose of 5.54 mSv for the total group of 56 persons. Chromosome aberrations were within the normal range when compared with historical controls with the exception of dicentrics (0.3% per cell, which is a 10-fold increase) and rings (0.07% per cell). A dose-dependent increase in dicentrics and rings based on caesium exposure was not observed.

Radiotherapy of liposarcomas.

A review of the literature of time-dose relationships of liposarcoma is given. The radiotherapeutic data on 15 measurable liposarcoma sites, together with 45 sites collected from the literature, are subjected to a Strandqvist plot analysis using the modified Ellis' formula TSD = D.T-alpha. The recovery coefficient alpha is thought to be rather high, of the order alpha = 0.5. This suggests that the use of a few large fractions in therapy may be beneficial.

Single-strand breaks in the DNA of human cells exposed to visible light from phototherapy lamps in the presence and absence of bilirubin.

Clinical evidence indicates that phototherapy of hyperbilirubinaemia in newborn infants is a safe and efficient form of therapy. The short-term side effects are not serious and seem to be well controlled. There are few long-term follow-up studies of phototherapy-treated infants. Therefore one cannot completely exclude the possibility that side effects can be found in future studies. With this background we undertook the present study of possible genotoxic effects of phototherapy. Human cells of the established glioblastoma cell line TMG-1 were used. The cells were exposed to visible light in the presence of different concentrations of bilirubin or in the absence of bilirubin. DNA was unwound in alkaline solution and the induction of strand breaks was assayed by a method taking advantage of the fluorescence from the dye Hoechst 33258. Blue light induced single-strand breaks in the DNA of cells in culture in the absence of bilirubin. During irradiation of bilirubin solutions with blue and green phototherapy light, long-lived toxic photoproducts were formed under in vitro conditions. At high and clinically relevant bilirubin concentrations, the effects of blue and green light were relatively similar. At low concentrations, there was a smaller effect of green light as expected from the absorption spectrum of bilirubin. It remains to be seen whether the genotoxic effect observed in the present studies can occur in vivo.

Cancer incidence among Norwegian airline pilots.

OBJECTIVES: In this retrospective cohort study, the cancer incidence of commercial pilots was studied to determine whether exposure at work has any influence on the incidence of cancer. METHODS: The cohort was established from the files of the Civil Aviation Administration and included people who had valid licenses as commercial pilots between 1946 and 1994. Basic data about their flight careers were recorded, and exposure to cosmic radiation was estimated. The cohort was linked to the Cancer Register of Norway. The observed number of cases was compared with that expected based on national rates. RESULTS: A group of 3701 male pilots was followed over 70 560 person-years. There were 200 cases of cancer versus 188.8 expected, with a standardized incidence ratio (SIR) of 1.06 and a 95% confidence interval (95% CI) of 0.92-1.22. No significant decreased risk was found for any cancer site. Excess risks were found for malignant melanoma (22 cases SIR 1.8, 95% CI 1.1-2.7) and nonmelanoma skin cancer (14 cases, SIR 2.4, 95% CI 1.3-4.0). For malignant melanoma, there was a significant trend for the SIR by cumulative dose. CONCLUSIONS: For most cancer sites, the incidence among pilots did not deviate from that of the general population and could not be related to block hours of flight time or dose. It seems more likely that the excess risks of malignant melanoma and skin cancer are explained by factors related to life-style rather than by conditions at work.

Incidence of cancer among workers in Norwegian hydroelectric power companies.

OBJECTIVES: The goal of this study was to examine whether exposure to electric or magnetic fields is related to cancer. METHODS: The study cohort consisted of 5088 men who had worked for at least one year between 1920 and 1991 for any of eight participating companies which produce and distribute hydroelectric power in Norway. The occupational exposure of these workers included extremely low-frequency electromagnetic fields. Incident cancer cases identified from the Cancer Registry of Norway were analyzed on the basis of the standardized incidence ratio with the Norwegian male population as reference. RESULTS: The incidence of cancer was close to unity for the cohort. The standardized incidence ratio for lymphoma was below unity, whereas those for leukemia and brain tumors were similar to those expected. Calculated cumulative exposure to electric or magnetic fields was not associated with the incidence of leukemia or brain tumors, but an excess of malignant melanoma was shown for the highest category of magnetic field exposure. An analysis of combined possible exposure to oils containing polychlorinated biphenyls and exposure to magnetic fields or possible exposure to electric sparks gave standardized incidence ratios of 265 and 280, respectively, for the higher exposure category. CONCLUSIONS: These results do not support the assumption of a possible association between exposure to electromagnetic fields and leukemia and brain tumors. The possible association between exposure to polychlorinated biphenyls or magnetic fields and risk of malignant melanoma should be further evaluated in future studies.

Area and time distribution of external and internal doses from Chernobyl fallout: the lack of correlation in Norway.

Population doses from external radiation and internal food-based radioactivity were calculated each month for each municipality for 3 y immediately following the Chernobyl contamination in Norway. The main polluted regions are sparsely populated but comprise important food production areas. The external dose data base was calculated based on fallout deposition and measurements in dwellings, whereas the totally independent internal dose data base was calculated on a large number of food measurements and knowledge of both the food distribution system and the countermeasures taken. The internal dose in the densely populated municipalities was comparably higher than expected from local deposition, despite the fact that countermeasures had some effect. Thus, the correlation between internal and external dose for individual municipalities is rather weak. This study shows that a traditional deposition/transfer factor approach may be inappropriate if used in countries with large variation in population density and agricultural ecosystems and in combination with effective countermeasures.