USTUR whole body case 0262: 33-y follow-up of PuO2 in a skin wound and associated axillary node

This whole body donation case (USTUR Registrant) involved two suspected PuO2 inhalation intakes, each indicated by a measurable Pu alpha activity in a single urine sample, followed about 1(1/2) y later by a puncture wound to the thumb while working in a Pu glovebox. The study is concerned with modelling simultaneously the biokinetics of deposition and retention in the respiratory tract and at the wound site; and the biokinetics of Pu subsequently transferred to other body organs, until the donor's death. Urine samples taken after the wound incident had readily measurable Pu alpha activity over the next 14 y, before dropping below the minimum detectable excretion rate (<0.4 mBq d(-1)). The Registrant died about 33 y after the wound intake, at the age of 71, from hepatocellular carcinoma with extensive metastases. At autopsy, all major soft tissue organs were harvested for analysis of their 238Pu, 239+240Pu and 241Am content. The amount of 239+240Pu retained at the wound site was 68 +/- 7 Bq (1 SD), measured by low-energy planar Ge spectrometry. A further 56.0 +/- 1.2 Bq was retained in an associated axillary lymph node, measured by radiochemistry. Simultaneous mathematical analysis (modelling) of all in vivo urinary excretion data, together with the measured lung, thoracic lymph node, wound, axillary lymph node and systemic tissue contents at death, yielded estimated intake amounts of 757 and 1504 Bq, respectively, for the first and second inhalation incidents, and 204 Bq for the total wound intake. The inhaled Pu material was highly insoluble, with an estimated long-term absorption rate from the lungs of 2 x 10(-5) d(-1). The Pu material deposited at the wound site was mixed: approximately 14% was rapidly absorbed, approximately 49% was absorbed at the rate of about 6 x 10(-5) d(-1), and the remainder ( approximately 37%) was absorbed extremely slowly (at the rate of about 5 x 10(-6) d(-1)). Thus, it was estimated that only approximately 40% of the Pu initially deposited in the wound had been absorbed systemically over the 33-y period until the donor's death. The biokinetic modelling also indicated that, in this individual case, some of the parameter values (rate constants) incorporated in the ICRP Publication 67 Pu model were up to a factor of 2 different from ICRP's recommended values (for reference man).

Spontaneous terminal ileitis resembling Crohn disease in captive tamarins

Five tamarins (four Saguinus mystax and one S. labiatus) died with wasting syndrome characterized by chronic diarrhea at the Center for Reproduction and Conservation of Non-Human Primates in Iquitos, Peru. At necropsy, the terminal ileum of all affected tamarins was found to be markedly thickened. Histologically, the terminal ileal mucosa was completely ulcerated, and effaced by debris and mononuclear inflammatory cells. The submucosa and serosa were thickened by fibroplasia, mononuclear cell infiltrates and variable edema. No infectious agent was observed. The lesions were similar to those described previously for Crohn disease. This is to our knowledge the first report of terminal ileitis resembling Crohn disease in non-human primates.

Clinical progression of transplanted large granular lymphocytic leukemia in Fischer 344 rats exposed to 60 Hz magnetic fields

The purpose of this study was to determine if 60 Hz magnetic fields can alter the clinical progression of leukemia in an animal model. Large granular lymphocytic (LGL) leukemia cells from spleens of leukemic rats were transplanted into young male Fischer 344 rats, producing signs of leukemia in approximately 2-3 months. The animals were randomly assigned to 4 treatment groups (108/group) as follows: 1) 10 G (1.0 mT) linearly polarized 60 Hz magnetic fields, 2) sham exposed [null energized unit with residual 20 mG (2 microT) fields], 3) ambient controls [<1 mG (0.1 [microT)], and 4) positive controls (a single 5 Gy whole body exposure to 60Co 4 days prior to initiation of exposure). All rats were injected intraperitoneally (ip) with 2.2 x 10(7) LGL leukemic cells at the initiation of exposure or sham exposure. The magnetic fields were activated for 20 h/day, 7 days/week, allowing time for animal care. The experimental fields were in addition to natural ambient magnetic fields. Eighteen rats from each treatment group were bled, killed, and evaluated at 5, 6, 7, 8, 9, and 11 weeks of exposure. Peripheral blood hematological endpoints, changes in spleen growth, and LGL cell infiltration into the spleen and liver were measured to evaluate the leukemia progression. No significant or consistent differences were detected between the magnetic field exposed groups and the ambient control group, although the clinical progress of leukemia was enhanced in the positive control animals. These data indicate that exposure to sinusoidal, linearly polarized 60 Hz, 10 G magnetic fields did not significantly alter the clinical progression of LGL leukemia. Furthermore, the data are in general agreement with previous results of a companion repeated-bleeding study in which animals were exposed for 18 weeks.

Two-step model for the risk of fatal and incidental lung tumors in rats exposed to radon

Data from 4276 rats with radon exposures up to 10,000 WLM at rates up to 1000 WL are analyzed with a two-step clonal expansion model. The age dependences of the hazard for the risks for fatal and for incidental tumors are very different. Therefore, two different parameterizations of the model are used in the two cases. In both cases radiation acts only on the initiating mutation and the clonal expansion, but not on the second mutation. Average exposure rates of 5 WL for fatal tumors and 0.5 WL for incidental tumors double the rate of spontaneous mutations. While the fatal tumors show a linear increase in the effective clonal expansion rate up to about 100 WL average exposure rate and a saturation at higher exposure rates, the incidental tumors follow a step-like behavior of this parameter. It is proposed that only the fatal lung tumors among the rats be used for generalizations to models for lung cancer in humans. The fitted model for fatal tumors shows an inverse dose-rate effect at average exposure rates above 20 WL. However, below 10 WL the lung cancer risk per unit exposure decreases with increasing duration of exposure. Between 10 and 20 WL, the difference in ERR/WLM between acute and protracted exposure is small.

Statistical modeling of carcinogenic risks in dogs that inhaled 238PuO2

Combined analyses of data on 260 life-span beagle dogs that inhaled 238PuO2 at the Inhalation Toxicology Research Institute (ITRI) and at Pacific Northwest National Laboratory (PNNL) were conducted. The hazard functions (age-specific risks) for incidence of lung, bone and liver tumors were modeled as a function of cumulative radiation dose, and estimates of lifetime risks based on the combined data were developed. For lung tumors, linear-quadratic functions provided an adequate fit to the data from both laboratories, and linear functions provided an adequate fit when analyses were restricted to doses less than 20 Gy. The estimated risk coefficients for these functions were significantly larger when based on ITRI data compared to PNNL data, and dosimetry biases are a possible explanation for this difference. There was also evidence that the bone tumor response functions differed for the two laboratories, although these differences occurred primarily at high doses. These functions were clearly nonlinear (even when restricted to average skeletal doses less than 1 Gy), and evidence of radiation-induced bone tumors was found for doses less than 0.5 Gy in both laboratories. Liver tumor risks were similar for the two laboratories, and linear functions provided an adequate fit to these data. Lifetime risk estimates for lung and bone tumors derived from these data had wide confidence intervals, but were consistent with estimates currently used in radiation protection. The dog-based lifetime liver tumor risk estimate was an order of magnitude larger than that used in radiation protection, but the latter also carries large uncertainties. The application of common statistical methodology to data from two studies has allowed the identification of differences in these studies and has provided a basis for common risk estimates based on both data sets.

Biological effects of inhaled 238PuO2 in beagles

Beagle dogs exposed to 238PuO2 aerosols (136 dogs, 13-22 per group, mean initial lung depositions of 0.0, 0.13, 0.68, 3.1, 13, 52 and 210 kBq) were observed throughout life to determine tissues at risk and dose-effect relationships. The pulmonary retention of 238Pu was represented by the sum of two exponentially decreasing components of the initial lung deposition; about 84% cleared with a 174-day half-time; the half-time of the remainder was 908 days. The average percentages of final body burden found in lung, skeleton, liver and thoracic lymph nodes in the 30 longest-surviving dogs (mean survival 14 years) were 1, 46, 42 and 6%, respectively. Of 116 beagles exposed to plutonium, 34 (29%) developed bone tumors, 31 (27%) developed lung tumors, and 8 (7%) developed liver tumors. Although lungs accumulated a higher average radiation dose than skeleton, more deaths were due to bone tumors than to lung tumors. Deterministic effects included radiation pneumonitis, osteodystrophy, hepatic nodular hyperplasia, lymphopenia, neutropenia and sclerosing tracheobronchial lymphadenitis. Hypoadrenocorticism was also observed in a few dogs. Increased serum alanine aminotransferase, indicative of liver damage, was observed in groups with > or =3.1 kBq initial lung deposition. Estimates of cumulative tissue dose in a human exposed to airborne 238PuO2 for 50 years at a rate of one annual limit on intake each year were derived based on a comparison of the data on metabolism for humans and beagles. The 50-year dose estimates for humans are an order of magnitude lower than doses at which increased incidence of neoplasia was observed in these dogs, whereas the projected doses to humans from 50-year exposure at the annual limit of intake are of similar magnitude to those at which deterministic effects were seen in the beagles.

Testicular atrophy in a mule deer population

Monitoring mule deer (Odocoileus hemionus) on a former plutonium production site along the Columbia River at the Hanford Site, Washington (USA) revealed 27 (23%) of 116 adult males had unusually shaped, velvet-covered antlers and abnormally developed testicles. We captured 32 males to examine age-class differences and the ratio of affected to unaffected deer and determine whether affected testicles were atrophic or hypoplastic. We found testicular atrophy in most deer with velvet-covered antlers, primarily in animals older than 5 yr. Deer had marked to extreme stages of testicular atrophy, indicating permanent sterility. Decreased serum levels of testosterone and compensatory increased levels of luteininzing hormone and follicle stimulating hormone were detected in all affected males; thus, the gondopituitary hormonal pathway may have responded to abnormally low levels of testosterone in the affected animals. Brucella spp. antibodies in sera were not detected and 9 (90%) of 10 affected animals were seropositive for epizootic hemorrhagic disease virus (EHDV-2) and bluetongue virus (BTV-11) as compared to 12 (63%) of 19 unaffected animals; however, signs of other infectious diseases were not observed. Testicular degeneration generally exceeded that observed with nutritional disorders and poisons in domestic species. Also, severity of the atrophy and apparent lack of other affected tissues suggested that radiation may not be responsible. Testicular atrophy in mule deer has been reported elsewhere; however, neither prevalence has been as high nor or occurrence as well confined to a specific geographical area, as that observed at the Hanford Site. Furthermore, no physiological or age-related influences were described. Documenting the status of such variables and examining their relationships to this phenomenon is a crucial step in understanding the reproductive capacity of a wild deer population.

Hypoadrenocorticism in beagles exposed to aerosols of plutonium-238 dioxide by inhalation

Hypoadrenocorticism, known as Addison's disease in humans, was diagnosed in six beagles after inhalation of at least 1.7 kBq/g lung of 238PuO2. Histological examination of adrenal gland specimens obtained at necropsy revealed marked adrenal cortical atrophy in all cases. Autoradiographs showed only slight alpha-particle activity. Although the pathogenesis of adrenal cortical atrophy in these dogs is unclear, there is evidence to suggest an autoimmune disorder linked to damage resulting from alpha-particle irradiation to the lymphatic system.

The distribution and effects of inhaled 239Pu(NO3)4 deposited in the liver of dogs

The distribution and effects of inhaled 239Pu(NO3)4 deposited in the liver of dogs were studied in five groups of 20 beagles exposed to initial lung depositions ranging from 1.0 to 520 Bq g(-1) lung. Following life-span observations, the liver contained 40 +/- 1% of the final body deposition of plutonium, second only to the skeleton. The liver-to-skeleton ratio of deposited plutonium for total organ was 0.8, or 3.5 when expressed on a per-gram basis. There was no effect of exposure level on liver-to-skeleton ratios. Autoradiographs showed that the dose rate delivered to parenchymal cells was higher than evident from radiochemical analysis of the whole organ. Elevated levels of serum liver enzymes were observed in groups with mean liver concentrations of 1.3 Bq g(-1) and liver doses of 3 Gy or higher. Nodular hyperplasia of liver and bile-duct hyperplasia were observed. Liver tumors, principally of bile-duct epithelium, were late-occurring and were observed at lower exposure levels at which life span was not shortened by lung or bone tumors.

Analysis of lung tumor risks in rats exposed to radon

Using data on 3117 rats exposed by inhalation to radon, radon progeny and uranium ore dust, the hazard function (or age-specific risk) for lung tumor incidence was modeled as a function of exposure, exposure rate and other factors. The overall estimate of lifetime risk was 237 cases per 10(6) rats per WLM (237 per 10(6) WLM), reasonably comparable to estimates obtained from data for humans. The data below 1000 WLM (20-640 WLM) were consistent with linearity with positive excess risks at all levels; however, evidence of statistically significant excess risk was limited to exposures of 80 WLM or greater. Evidence for an inverse exposure-rate effect was limited primarily to cumulative exposures exceeding 1000 WLM (1280-10,240 WLM) and to comparison of results at 100 and 1000 WL. Even at these levels, the possibility that the effect might be explained by time since last exposure or by heterogeneity across experiments could not be entirely excluded. The inverse exposure-rate effect was strongest for epidermoid and adenosquamous tumors, and the only indication of such an effect at exposures below 1000 WLM was modest evidence (P=0.024) in analyses limited to these tumors. When all lung tumors, or all malignant lung tumors, were included, there was no evidence of such an effect below 1000 WLM. These data support the viewpoint that the inverse exposure-rate effect is primarily a high-dose phenomenon.

Hepatic effects of inhaled plutonium dioxide in beagles

The effects of inhaled 238PuO2 deposited in the liver of dogs were studied in beagles exposed to initial lung depositions ranging from 5.7 to 2979.7 Bq/g lung. Approximately 20% of the initial lung deposition was translocated to the liver by 1500 days after exposure. Life-span observations revealed that the liver contained 40% of the final body burden of plutonium, second only to the skeleton. Elevated serum liver enzyme activities were observed in dogs with final liver depositions of > or = 0.4 Bq/g, cumulative dose to the liver of > or = 0.18 Gy and annual dose rate > or = 0.02 Gy/year. Enzyme elevations were seen at one dose level lower than that in which bone or lung tumors were observed. Linear regression analysis revealed strong to moderate correlation between cumulative dose and dose rate and time to observed increases in liver enzyme activities. Liver tumors were late-occurring neoplasms observed at lower exposure levels where life span was not shortened by lung and bone tumors.

Hematological effects of inhaled plutonium dioxide in beagles

A life-span study indicated that plutonium activity in the thoracic lymph nodes is a contributor to development of lymphopenia in beagles exposed to 239PuO2. Significant lymphopenia was found in 67 (58%) beagles given a single nose-only exposure to 239PuO2 to result in mean initial lung depositions ranging from 0.69 to 213.3 kBq. Lymphoid atrophy and sclerosis of the thoracic lymph nodes and lymphopenia were observed in exposure-level groups with initial lung depositions > or = 2.5 kBq. Those dogs with final plutonium concentrations in the thoracic lymph nodes > or = 0.4 kBq/g and dose rates > or = 0.01 Gy/day developed lymphopenia. Marked differences existed between chronically lymphopenic dogs and intermittently lymphopenic dogs with regard to initial lung deposition, time to lymphopenic events and absolute lymphocyte concentrations. Linear regression analysis revealed moderate correlation between reduction in lymphocyte values and initial lung deposition, in both magnitude and time of appearance after exposure. Cumulative dose and dose rate appeared to act together to produce initial effects on lymphocyte populations, while dose rate alone appeared to be responsible for the maintenance and subsequent cycles of lymphopenia seen over the life span. No primary tumors were associated with the thoracic lymph nodes in this study, although 70% of the lymphopenic dogs developed lung tumors.

Examination of testicular tumours in the beagle dog exposed to inhaled plutonium

Gross and light microscopic features of testicular neoplasms were examined in the male beagle dog used in three studies to examine the life-span effects of inhaled plutonium (Pu). One hundred and sixty-six cases of testicular neoplasia (TN) occurred among 105 dogs that ranged in age from 7.5 to 17.7 years at the time of diagnosis. The 166 cases of TN comprised 113 interstitial cell tumours, 27 seminomas in situ, 19 seminomas, and seven Sertoli cell tumours. Serum testosterone and estradiol 17-beta concentrations, and the serum testosterone-to-oestradiol ratio were determined in 39 dogs with TN and in five clinically normal, sexually intact, age-matched cohorts. Serum hormone concentrations did not differ significantly among tumour types or between dogs with neoplasms and age-matched cohorts. There was a significant relationship between initial lung deposition (ILD) of Pu and activity in the testis (Bq/g testis). The slope of the relationship was 0.35, 0.89 and 0.91 for 239PuO2, 238PuO2 and 239Pu(NO3)4 respectively. Pu in the testis at long times (> 5 years) after inhalation was between 0.0001 and 0.03% ILD, depending on the physicochemical form of Pu. Although the mean activity of Pu in the testis of dogs was higher in those life-span studies employing 238PuO2 and 239Pu(NO3)4, the cumulative proportion of dogs with tumours, the distribution of tumour types, and mean time to first tumour was not significantly different among the three studies or dose groups, including controls, within a study.

Spontaneous colitis cystica profunda in captive tamarins

Of the 232 tamarins (133 Saguinus mystax and 99 Saguinus labiatus) that died at the Center for Reproduction and Conservation of Nonhuman Primates in Iquitos, Peru from January 1987 to December 1990, 23 monkeys (9.9%) were diagnosed as having chronic colitis. Typically, the cecal and colonic mucosa was greyish and small yellowish cysts, measuring 1-4 mm, were found randomly distributed bulging the mucosa. Microscopically, colitis cystica profunda was diagnosed additionally in six more animals, giving a total of 29 cases (12.5%). This is the first report to our knowledge that describes colitis cystica profunda in a nonhuman primate.

Primary renal hemangiosarcoma in a moustached tamarin

A wild-caught adult female Saguinus mystax died after 54 months in captivity. At necropsy, a small reddish zone in the renal cortex of one kidney was shown histologically to be a hemangiosarcoma.

Radiographically determined growth dynamics of primary lung tumors induced in dogs by inhalation of plutonium

Beagles were exposed to aerosols of 239PuO2, 238PuO2, or 239Pu(NO3)4. Exponential growth constants for 50 primary lung tumors (23 bronchioloalveolar carcinomas, 22 papillary adenocarcinomas, 5 adenosquamous carcinomas) were calculated in 37 dogs, using sequential thoracic radiography. A wide range in doubling time (6 to 287 days) was observed. Mean +/- SEM doubling time was 93 +/- 10 days for bronchioloalveolar carcinoma, 107 +/- 13 days for papillary adenocarcinoma, and 101 +/- 36 days for adenosquamous carcinoma. Lung tumor growth rate in dogs was comparable to that in human patients with similar histologic tumor types. Linear regression analysis revealed significant (P < or = 0.0001) correlation between doubling time and survival of individual dogs. Doubling time was not significantly dependent on tumor type, sex, age at time of diagnosis, initial lung deposition, or isotope. Extrapolating time to tumor onset from tumor doubling time cannot be used to reliably predict the onset of malignancy.

Primary pulmonary chondrosarcoma in a dog

Extraosseous chondrosarcomas are uncommon in the dog, and those originating in the lung are rare. This report presents a 9-year-old Beagle dog with a pulmonary mass which caused depression, fever, tachypnea, cough, and laboratory abnormalities. The mass was composed predominantly of chondroid tissue, and was histologically diagnosed as chondrosarcoma.

Incidence of brain tumours in rats exposed to an aerosol of 239PuO2

Incidence of brain tumours was investigated in 3390 female and male Wistar rats exposed to an aerosol of 239PuO2, or as sham-exposed controls. Lung doses ranged from 0.05 to 22 Gy. In females, six brain tumours were found in 1058 control rats (incidence, 0.6%) and 24 brain tumours in 2134 rats exposed to Pu (incidence, 1.1%); the survival-adjusted level of significance was p = 0.29 for comparing control with exposed females. In males, two brain tumours were found in 60 control rats (incidence, 3.3%) and seven brain tumours in 138 rats exposed to Pu (incidence, 5.1%); the survival-adjusted level of significance was p = 0.33. Brain tumour incidence was about five times greater in male than in female rats (p = 0.0001), demonstrating a highly significant sex difference in brain tumour incidence. Tumour types were distributed similarly among control and Pu-exposed groups of both sexes; most tumours were astrocytomas. Mean lifespans for rats with brain tumours were not significantly different between control and Pu-exposed rats. Plutonium was not detected on autoradiograms of the brain. These results, like those for plutonium workers, show an increase of brain tumours which cannot be demonstrated statistically to be related to radiation exposure.

Spontaneous cardiomyopathy resembling acute rheumatic heart disease in an owl monkey

A wild-caught male Aotus vociferans died spontaneously during quarantine. Histologic examination of the heart showed several small myocardial arteries replaced with fibrinoid necrosis and adjacent inflammation that included lymphocytes and large histiocytic cells. Less often, similar inflammatory foci were observed in the myocardium interstitium. The lesions observed in the heart of the owl monkey resembled Aschoff bodies.

Spontaneous cardiomyopathy and nephropathy in the owl monkey (Aotus sp.) in captivity

Clinical and pathologic data were reviewed for 72 owl monkeys that died between January 1987 and May 1990 at the Center for Reproduction and Conservation of Nonhuman Primates in Iquitos, Peru. Tissue samples from 39 animals were examined. Hypertrophic cardiac disease (51% of animals examined), dilative cardiomyopathy (26%), and nephropathy (87%) were the most common diagnoses. The incidence of all three diseases appeared to increase with time in captivity. Nephropathy was less severe in colony-born animals.

Elevated epidermal growth factor receptor binding in plutonium-induced lung tumors from dogs

The objective of this study is to examine and characterize epidermal growth factor receptor (EGF-R) binding in inhaled plutonium-induced canine lung-tumor tissue and to compare it with that in normal canine lung tissue. Crude membrane preparations from normal and lung-tumor tissue from beagle dogs were examined in a radioreceptor assay, using 125I-labeled epidermal growth factor (EGF) as a ligand. Specific EGF receptor binding was determined in the presence of excess unlabeled EGF. We have examined EGF receptor binding in eight lung-tumor samples obtained from six dogs. Epidermal growth factor receptor binding was significantly greater in lung-tumor samples (31.38%) compared with that in normal lung tissue (3.76%). Scatchard plot analysis from the displacement assay revealed that there was no statistical difference in the binding affinity but significantly higher concentration of EGF-R sites in the lung-tumor tissue (619 fmol/mg) than in normal lung tissue (53 fmol/mg). The increase in EGF-R number in plutonium-induced dog lung tumors does not seem to correlate with increase in the initial lung burden exposure to plutonium. Our results demonstrate that there is a significant increase in EGF-R binding in inhaled plutonium-induced dog lung tumors.

Cholelithiasis in owl monkeys: seven cases

Spontaneous cholelithiasis was found in seven owl monkeys (Aotus spp.) at necropsy. There were four male and three female animals. Antemortem clinicopathologic findings included weight loss, anemia, increased alanine aminotransferase and gamma glutamyl transpeptidase, and hyperbilirubinemia in several animals. Choleliths ranged in size from sand-like particles to 5 mm in diameter. Gallstones from five animals were analyzed by accepted analytical methods. Results showed the gallstones to be composed primarily of cholesterol (89%). The gallbladder was histologically normal in all cases examined. The etiopathogenesis of cholelithiasis in the owl monkey is unknown.

Pulmonary carcinogenesis in rats given implants of shale oil in beeswax pellets

Pellets of crude shale oil, neutral, basic, or polynuclear aromatic fractions of shale oil, or crude petroleum were implanted in the lungs of rats through a thoracotomy. The pellets had a beeswax-tricaprylin vehicle that allowed the slow release of material into the surrounding parenchyma. A dose-related incidence of lung cancer was observed with each of the materials studies. A greater risk for lung cancer was not demonstrated for crude shale oil compared to crude petroleum.

A two-mutation model for radon-induced lung tumors in rats

The recessive oncogenesis model, according to which inactivation of both alleles of specific genes leads to cancer, has received much recent attention. A mathematical formulation of a two-mutation model for carcinogenesis, which includes the recessive oncogenesis model as a special case, was fitted to data from a large experimental study in which rats exposed to radon daughters developed malignant lung tumors. The model described the data well. The results indicate that fractionation of exposure increased the lifetime probability of tumor. Examination of the parameters of the model suggests that the effect of fractionation can be explained by the relative effects of radon daughters on the mutation rates and on the kinetics of growth of initiated cells. The first mutation rate is very strongly dependent upon the rate of exposure to radon daughters, the second mutation rate much less so, suggesting that the nature of the two mutational events is different. The model makes predictions which are testable in future experiments.

Toxicology of 85Kr: chronic exposure studies

Male and female Wistar rats were exposed chronically to graded doses of 85Kr to determine long-term biological effects of simulated environmental exposure. Rats were exposed in 4 groups, including room air-exposed controls and 3 groups exposed to 85Kr concentrations equivalent to 10(2), 10(3) and 10(4) times the maximum permissible concentration (MPC) for the general population (3 X 10(-7) microCi/ml). Exposures continued 24 hr/day, 7 days/week for 808 days, until only approximately 10% of the original 400 rats were alive. No effect of 85Kr exposure was observed on weight gain or tumor incidence, including leukemias. The results support the adequacy of established 85Kr exposure limits for the general population in light of the absence of evidence of build-up in tissues after chronic exposure and the lack of exposure-related biological effects in rats after near-lifespan exposure to concentrations equivalent to 10,000 times the MPC.

Plutonium-induced wounds in beagles

Beagle dogs were given subcutaneous implants of plutonium in their forepaws to mimic hand wounds received by workers accidentally contaminated with plutonium. Ten dogs received 9.46 +/- 0.43 mu Ci of plutonium oxide, and eight dogs received 1.25 +/- 0.60 mu Ci of plutonium nitrate. Surviving dogs were sacrificed at 8 and 5 yr, respectively, after exposure, and radionanalyses were performed on the injection site, regional lymph nodes, liver, spleen and bone. Histopathologic and autoradiographic examinations were performed on injection sites, regional lymph nodes, livers, spleens, kidneys and grossly observed lesions. The injected paws sequestered 21 and 16%, respectively, of the injected activity from plutonium oxide and plutonium nitrate in hypocellular scar tissue. The highest concentrations of translocated radionuclides were found in the regional lymph nodes. Histopathologic and autoradiographic examinations of regional lymph nodes showed that the alpha activity was largely sequestered by scar tissue that replaced lymphoid parenchyma in the plutonium-oxide-injected dogs. In the plutonium-nitrate-injected dogs, activity was widely distributed in relatively intact regional lymph nodes. The liver had the next highest concentration for both radionuclides; activity was present as alpha stars. The spleen had the next highest concentration for plutonium-oxide-injected dogs, although concentrations in the spleen were lower than the skeleton in the plutonium-nitrate-injected dogs. Osteosarcomas and hepatomas were present in one dog injected with plutonium oxide. There does not appear to be any unique risk for dogs related to the subcutaneous route of exposure to plutonium.

Radionuclide injury to the lung

Radionuclide injury to the lung has been studied in rats, hamsters, dogs, mice and baboons. Exposure of the lung to high dose levels of radionuclides produces a spectrum of progressively more severe functional and morphological changes, ranging from radiation pneumonitis and fibrosis to lung tumors. These changes are somewhat similar for different species. Their severity can be related to the absorbed radiation dose (measured in rads) produced by alpha, beta or gamma radiation emanating from various deposited radionuclides. The chemicophysical forms of radionuclides and spatial-temporal factors are also important variables. As with other forms of injury to the lung, repair attempts are highlighted by fibrosis and proliferation of pulmonary epithelium. Lung tumors are the principal late effect observed in experimental animals following pulmonary deposition of radionuclides at dose levels that do not result in early deaths from radiation pneumonitis or fibrosis. The predominant lung tumors described have been of epithelial origin and have been classified, in decreasing frequency of occurrence, as adenocarcinoma, bronchioloalveolar carcinoma, epidermoid carcinomas and combined epidermoid and adenocarcinoma. Mesothelioma and fibrosarcoma have been observed in rats, but less commonly in other species. Hemangiosarcomas were frequency observed in dogs exposed to beta-gamma emitters, and occasionally in rats exposed to alpha emitters. These morphologic changes in the lungs of experimental animals were reviewed and issues relevant to the prediction of human hazards discussed.

Lung changes in rats inhaling volcanic ash for one year

Rats were exposed to 5 mg/m3 or 50 mg/m3 (respirable aerosol concentration) volcanic ash, or to 50 mg/m3 quartz, 6 h/day, 5 days/wk, for as long as 12 months. Subgroups of rats were killed at 4-month intervals to determine lesion development as a function of dose and cumulative exposure. Treatment-related lung changes comprised alveolar macrophage accumulation, interstitial reaction, peribronchiolar lymphoid hyperplasia, lymph node hyperplasia, and--in the 50 . mg/m3 ash-exposed and quartz-exposed rats--alveolar proteinosis. Some of the changes did not increase appreciably after 8 months of exposure, whereas others continued to increase as a function of cumulative exposure. Generally, there were distinct dose-response and agent-response relationships. These trends were also observed in lung weights, respiratory rates, and volumes of mediastinal lymph nodes. Like the histologic changes, the effects on these ancillary parameters also increased in the following order: sham-exposed control group, 5 mg/m3 and 50 mg/m3 ash-exposed groups, and quartz-exposed positive control group.

Early effects of inhaled Ca-DTPA on the rat lung

Inhalation of calcium trisodium diethylenetriaminepentaacetate (Ca-DTPA) increases the removal of plutonium and other transuranics from the body. Data are required to determine possible biological effects from inhaled DTPA. Female rats were given a single or 12 daily, 2-4 h, inhalation exposures to aerosols of 10, 20 and 40% Ca-DTPA and the lungs were examined at 21 and 42 days following the last exposure. No pulmonary pathology was found from the single inhalation treatment with Ca-DTPA while only a slight, peripheral, histiocytosis was observed in the lungs of multiple-treated rats. There was no significant effect of DTPA treatments on body weight, lung weight, hematology or serum chemistry values.

Effects of d-norgestrel-releasing intracervical devices in the nonhuman primate, Erythrocebus patas

Primates (Erythrocebus patas) were implanted with intracervical devices which slowly released d-norgestrel at either of two rates: 38 +/- 12 microgram/day (high dose, 4 animals) or 14 +/- 10 microgram/day (low dose, 3 animals). An additional 8 animals received placebo devices or were untreated controls. All animals were studied for 3 months of exposure, at which time they were necropsied and evaluated. The uterus in all of the high dose primates had endometrial stromal and epithelial hyperplasia and, in two primates, suppurative endometritis. Similar, but less severe, uterine changes were present in animals of the low dose group. Systemic effects included evidence of diminished menstrual cycling and an absence of corpora lutea at both dose levels. Our results indicate that local application of these levels of d-norgestrel for contraception produces effects similar to those from systemically administered d-norgestrel.

Morphology of spontaneous brain tumors in the rat

In lifespan studies of 2,242 rats of three strains, 32 neoplasms were identified in brain, meninges and pineal gland. They were astrocytoma (16 Wistar, three Sprague-Dawley), ependymoma (four Osborne-Mendel), meningioma (two Osborne-Mendel, one Wistar), pinealoma (two Osborne-Mendel), reticulosis (two Wistar), oligodendroglioma (one Wistar), and gliomatosis (one Wistar).

Pulmonary carcinogenesis in rats given implants of cigarette smoke condensate in beeswax pellets

Lungs of inbred OM/NCR and outbred Sprague-Dawley rats were given implants, through a thoracotomy, of pellets of cigarette smoke condensate (CSC) suspended in a beeswax-tricaprylin vehicle. The pellets slowly released material into the surrounding parenchyma, which resulted in a dose-related increased incidence of lung cancer, predominantly invasive and metastasizing epidermoid carcinoma. A 42% prevalence of pulmonary carcinoma was present in the highest dosage group, which received 67 mg CSC, exposing approximately 1.65 cm2 bronchiolar epithelium. Squamous metaplasia associated with the implanted site preceded the appearance of the carcinomas and was more severe, with the larger pellets having more concentrated CSC. No difference was observed in incidence of pulmonary carcinomas with the use of CSC containing high or low concentrations of nicotine. The potential value of this bioassay system were discussed.

Naturally occurring Tyzzer's disease and intestinal spirochetosis in guinea pigs

Bacillus piliformis infection (Tyzzer's disease) occurred in two young guinea pigs, causing unthriftiness and diarrhea which resulted in death. There was necrosis and inflammation of the ileum, cecum, and colon. Intestinal epithelial cells contained organisms resembling Bacillus piliformis. Spirochetes were found in the cecum and colon, mainly in crypts. Acute diarrhea occurred in another guinea pig which became cachetic and was killed. Histologically, large numbers of spirochetes were present in the wall of both the cecum and colon, and they were associated with severe necrosis and inflammation. Bacillus pilformis was not found in this animal.

Acute myelomonocytic leukemia manifested as myelophthisic anemia in a dog

A 10-year-old, Golden Retriever-type castrated male dog was found to have a hemogram consistent with myelophthisic anemia. Within 30 days the hemogram changed in such a manner that a myeloproliferative disorder was evident. On the basis of hematologic, cytochemical, and cytologic findings, acute myelomonocytic leukemia was diagnosed.