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PubMed1975

[Proceedings: Lung lesions caused by "rare earths"].

Three reproduction photographers were found to have light patchy and reticular infiltrates on the chest x-rays. They had a 30-year history of inhaling "rare earths" and thorium deriving from the dust of the electric carbon arc-light. The diagnosis was confirmed by whole-body gamma-counting in all cases and by additional lung biopsy in one. This type of pneumoconiosis shows no definite disease progression and no serious functional deterioration.

Aged↗
PubMed2003

Quantitative comparisons of cancer induction in humans by internally deposited radionuclides and external radiation.

PURPOSE: To compare quantitative estimates of lifetime cancer risk in humans for exposures to internally deposited radionuclides and external radiation. To assess the possibility that risks from radionuclide exposures may be underestimated. MATERIALS AND METHODS: Risk estimates following internal exposures can be made for a small number of alpha-particle-emitting nuclides. (1) Lung cancer in underground miners exposed by inhalation to radon-222 gas and its short-lived progeny. Studies of residential (222)Rn exposure are generally consistent with predictions from the miner studies. (2) Liver cancer and leukaemia in patients given intravascular injections of Thorotrast, a thorium-232 oxide preparation that concentrates in liver, spleen and bone marrow. (3) Bone cancer in patients given injections of radium-224, and in workers exposed occupationally to (226)Ra and (228)Ra, mainly by ingestion. (4) Lung cancer in Mayak workers exposed to plutonium-239, mainly by inhalation. Liver and bone cancers were also seen, but the dosimetry is not yet sufficiently good enough to provide quantitative estimates of risks. Comparisons can be made between risk estimates for radiation-induced cancer derived for radionuclide exposure and those derived for the A-bomb survivors, exposed mainly to low-LET (linear energy transfer) external radiation. Data from animal studies, using dogs and rodents, allow comparisons of cancer induction by a range of alpha- and beta-/gamma-emitting radionuclides. They provide information on relative biological effectiveness (RBE), dose-response relationships, dose-rate effects and the location of target cells for different malignancies. RESULTS: For lung and liver cancer, the estimated values of risk per Sv for internal exposure, assuming an RBE for alpha-particles of 20, are reasonably consistent with estimates for external exposure to low-LET radiation. This also applies to bone cancer when risk is calculated on the basis of average bone dose, but consideration of dose to target cells on bone surfaces suggests a low RBE for alpha-particles. Similarly, for leukaemia, the comparison of risks from alpha-irradiation ((232)Th and progeny) and external radiation suggest a low alpha RBE; this conclusion is supported by animal data. Risk estimates for internal exposure are dependent on the assumptions made in calculating dose. Account is taken of the distribution of radionuclides within tissues and the distribution of target cells for cancer induction. For the lungs and liver, the available human and animal data provide support for current assumptions. However, for bone cancer and leukaemia, it may be that changes are required. Bone cancer risk may be best assessed by calculating dose to a 50 micro m layer of marrow adjacent to endosteal (inner) bone surfaces rather than to a single 10 micro m cell layer as currently assumed. Target cells for leukaemia may be concentrated towards the centre of marrow cavities so that the risk of leukaemia from bone-seeking radionuclides, particularly alpha emitters, may be overestimated by the current assumption of uniform distribution of target cells throughout red bone marrow. CONCLUSIONS: The lifetime risk estimates considered here for exposure to internally deposited radionuclides and to external radiation are subject to uncertainties, arising from the dosimetric assumptions made, from the quality of cancer incidence and mortality data and from aspects of risk modelling; including variations in baseline rates between populations for some cancer types. Bearing in mind such uncertainties, comparisons of risk estimates for internal emitters and external radiation show good agreement for lung and liver cancers. For leukaemia, the available data suggest that the assumption of an alpha-particle RBE of 20 can result in overestimates of risk. For bone cancer, it also appears that current assumptions will overestimate risks from alpha-particle-emitting nuclides, particularly at low doses.

Animals↗
PubMed2001

[Determination of content and specific activity of radioactive elements in phosphate slag by spectral and energy spectrum analysis].

Phosphate slag is the slag discarded after phosphate ore is smelted. The content and specific activity of radioactive elements in slag must be determined accurately for environmental protection and comprehensive utilization. This paper discusses how IR spectrum and X-ray diffraction method are used to study its components. The main phase composition is glassy slag. The samples are decomposed with HF-HNO3-HClO4. After anion-exchange separation, arsenazo III is used to determine the content of uranium and thorium in slag. The average content of U is 32.11 micrograms.g-1 and 8.5 micrograms.g-1 for Th. gamma spectrum is used to determine the specific activity of radioactive nuclear elements in it. The specific activities of 226Ra, 232Th and 40K are 112 +/- 2.0% Bq.kg-1, 18.8 +/- 6.4% Bq.kg-1 and 77.6 +/- 3.7% Bq.kg-1, respectively. The values are calculated as follow: M(Ra) = 0.6 Bq.kg-1, M gamma = 0.5 Bq.kg-1. The results show that the values are below 1.0 Bq.kg-1, which is stipulated by national GB6566-86 standard for radioactivity of building materials. The slag is therefore can be utilized to produce slag cement. This provides theoretical basis for the treatment of it.

Elements, Radioactive↗
PubMed1992

[A surprising double tumor of the liver 60 years following thoratrast diagnosis].

A 66-year-old man with thorotrastosis of the reticuloendothelial system is described. Post mortem two tumours were found in an enlarged liver: a cholangiocarcinoma and an angiosarcoma. Coincidentally, a hilar neurofibroma was found. The former two tumours most probably developed because of a lifelong endogenous alpha-irradiation by thorium disintegration. The exceptional latency period of 60 years' duration is emphasized.

Adenoma, Bile Duct↗
PubMed1979

[Thorotrastoses--viewed in retrospect (author's transl)].

Thorium dioxide (Thorotrast) was used as a contrast medium from 1930 to 1945. It gave excellent contrast and was well tolerated during the application, but due to its radioactivity and its long biological half life it caused various late complications as fibrosis and malignant tumors. The late side effects of the substance are reported on, and the most frequent complication--the induction of hepatomas--is illustrated by two cases.

Angiography↗
PubMed1989

[Levels of internal irradiation of the population of the RSFSR by natural alpha emitters].

The values of regional mean concentrations of natural radionuclides in the teeth samples of the RSFSR residents vary within 130-203 mBk/kg for 238U, 174-490 mBk/kg for 226Ra, 1.8-3.4 Bk/kg for 210Pb, 26-56 mBk/kg for 232Th, 50-150 mBk/kg for 228Th. The mean values of 238U in osseous tissue and teeth are similar and equal 120 +/- 35 and 112 +/- 38 mBk/kg, respectively. Radioactive balance between 228Th and 232Th in osseous tissue is absent. The ratio of the concentration of 228Th/232Th is on the average equal to 2.4 +/- 0.9 and of 220Th/832Th doesn't exceed 1.3. The distribution of regional mean concentrations of radionuclides of uranium and thorium series complies with standard distribution. An annual effective equivalent internal dose obtained because of natural alpha-emitters has been calculated for the population of the RSFSR.

Air Pollutants, Radioactive↗
PubMed1985

Thorotrast-associated liver cancer.

Thorotrast-related liver cancer is rare. A case of such cancer is presented. Thorotrast had been used intravenously in 1947, 38 years preceding the detection of cancer. A brief history of the use of colloidal solution of thorium dioxide (thorotrast) as a contrast material is discussed, along with a review of literature. Potential hazards of thorotrast in its carriers and a close follow-up are emphasized.

Adenoma, Bile Duct↗
PubMed1977

The structure of mononuclear phagocytes differentiating in vivo. III. The effect of particulate foreign substances.

The response of mononuclear phagocytes to three inert particles--barium sulfate, talc, and thorium dioxide--was studied by correlated light and electron microscopy. All three particles induced maturation of the mononuclear phagocytes, which proceeded to the stage of the mature macrophage and required 7 to 9 days. Once established, maturation persisted as long as 45 days, as did the inert particles. The resultant lesions, dense aggregates of mature macrophages, were termed mature granulomas. The resultant maturation differed from that produced by digestible bacteria in tempo and extent but not in pattern.

Animals↗
PubMed1987

Glycosaminoglycans (macromolecular sugars) of the rat renal papilla: ultrastructural and cytochemical findings.

Sulfated glycosaminoglycans have been stained at the ultrastructural level in interstitial matrix of the rat renal papilla, using colloidal thorium dioxide at low pH. Concentration of these proteoglycans was maintained during diuresis, and was thought to be greatly diminished during antidiuresis. The possible relation of these findings to the kidney's mechanism for urine concentration and dilution is discussed.

Animals↗
PubMed1986

Thorotrast-associated anemia and bone marrow hypoplasia.

Two patients with chronic anemia and bone marrow hypoplasia secondary to Thorotrast deposition are described. In one case thorium dioxide was identified by histoautoradiography, scanning electron microscopy, and x-ray spectrometry.

Aged↗
PubMed1985

Mesangial fenestrations, sieving, filtration, and flow.

Small tracers in the circulation enter the rat mesangium rapidly and in large amounts that indicate a sizable plasma flow into the mesangium. Entrance is effected through mesangial fenestrations with a mean width in scanning electron microscopy of 376 A, a size similar to fenestrations in peripheral glomerular capillary walls. This is considerably smaller than the mean size of 678 A found with transmission electron microscopy, but the difference is probably due largely to the anionic surface coat on endothelial cells. Measurements of asymmetric thorium dioxide particles show that smaller ones with a mean length of 315 A enter the mesangium preferentially and that larger particles with a mean length of 405 A are partially restricted, supporting the idea that the measured width in scanning electron microscopy is close to the actual width in vivo. Fluid flow into the mesangium requires fluid flow out. The appearance time and accumulation of tracers suggest the following exit paths of flow from the mesangium: through the overlying epithelium into the urinary space contributing to glomerular filtration and concentrating large tracers beneath the basement membrane in the paramesangial region, into the efferent glomerular capillaries after tracers have been filtered out by the fibrillar matrix, and through the hilus into the juxtaglomerular apparatus (quantitatively small).

Animals↗
PubMed1975

Ultrastructural comparison of the cell coat in normal and chronic lymphocytic leukaemic blood lymphocytes by Concanavalin A labelling and cationic staining.

The ultrastructure of the cell coat of normal and chronic lymphocytic leukaemic (CLL) blood lymphocytes has been compared by several cytochemical techniques. In CLL lymphocytes, there is no modification of Concanavalin A labelling, whereas a difference of stainability is observed with at least one of the three cationic dyes used: colloidal iron, colloidal thorium, or ruthenium red, signifying a modification of anionic reactive sites. This physico-chemical surface anomaly is discussed with regard to other biochemical and electrophoretic results given by other authors.

Cell Membrane↗
PubMed1978

[Light-chain plasmacytoma with reversible renal insufficiency after intravascular application of thorotrast (author's transl)].

Thirty-three years after intravascular injection of Thorotrast, a light-chain plasmacytoma with hypercalcemia and renal insufficiency was diagnosed in a 60-year-old man. The question of causal relation between Thorotrast deposit and plasmacytoma is discussed. The accumulated radiation load to the bone-marrow as caused by thorium dioxide deposition amounts to circa 3000 rem. According to casuistic and epidemiological communications, induction of plasmacytomas by external X-irradiation may be regarded as possible. A distinct increase in myeloproliferative diseases but only small numbers of plasmacytomas are reported in extensive epidemiological Thorotrast studies. From combination of results of the three most comprehensive epidemiological Thorotrast studies is obtained a numerical ratio of 1:5 for the spontaneous rate against the number of plasmacytomas observed. Identical correlations are yielded by investigations at Hiroshima and Nagasaki. Hence it is to be supposed that also plasmacytomas can be induced by thorotrastosis of the reticulohistiocytic system.

Acute Kidney Injury↗
PubMed1984

[Thorotrast deposits in the RES of the liver and spleen--a rare but characteristic roentgen diagnosis].

Finely reticulated or granulated shadows of liver and spleen, as well as metal-dense shadows of abdominal lymph nodes are characteristic roentgen findings in thorotrastosis. Thorium dioxide (Thorotrast) was used as a contrast medium from 1930-1950. It yielded excellent contrast and was well tolerated, but due to its radioactivity and its long biological half-life it caused manifold late complications. The typical roentgen findings in thorotrastosis are illustrated by two cases; the importance of thorotrastosis is discussed on the basis of relevant literature.

Diagnosis, Differential↗
PubMed1983

[Determination of 238U, 234U, 226Ra and 228Ra in spring waters of sanin district].

The 238U, 234U, 226Ra and 228Ra concentrations in the spring waters at the Sanbe and Misasa districts in Japan were investigated. In the spring water at Sanbe, high concentrations of the natural nuclides described above were found in which the maximum levels of 238U and 234U were 0.44 Bq/l and 0.91 Bq/l, respectively, while 234U/238U showed the range of 1.50 approximately 2.37. The maximum levels of 226Ra and 228Ra were found to be 1.95 Bq/l and 0.76 Bq/l, respectively, while 228Ra/226Ra mean value was 0.49. In the spring water at Misasa, the maximum levels of 226Ra and 228Ra were 0.60 Bq/l and 0.41 Bq/l, respectively, and 228Ra/226Ra mean value was 0.55. From the above-mentioned result and the fact that 228Ra is a decayed product of 232Th, it is thought that the rocks of the Sanbe and Misasa districts contain much uranium and thorium.

Fresh Water↗
PubMed1981

[Toxic and metabolic liver injury (author's transl)].

Water soluble exogenous compounds are commonly excreted by the kidneys, but most of the exogenous substances are lipid soluble and have therefore first to be metabolized in the liver to water soluble compounds. Depending upon the nature of the chemical compound, the metabolism in the liver leads either to detoxification or toxification. Alcohol belongs to the most important substances which may cause severe liver injury. Alterations of the liver due to hydrocarbons as well as carcinogens, mycotoxins and thorium dioxide are relatively rare. Compounds such as analgesic and antiarrhythmic drugs, antibiotics, oral antidiabetic agents, antihypertensive and antirheumatic agents, chemotherapeutic drugs, hormones, laxatives, psychotropic drugs, thyreostatic and antineoplastic agents may also cause liver injury. For establishing the diagnosis, a detailed past history is required especially with respect to alcohol and drug consumption as well as regarding occupational exposure towards toxic compounds. Although the determination of liver enzyme activities in the serum may give some indication for liver cell injury, the histological examination of the liver by needle biopsy is required for the diagnosis. The therapy consists of the exclusion of the toxic compound and, if possible, of an increased elimination of the ingested toxins.

Alcoholic Intoxication↗
PubMed1981

[Carcinoma of the kidney and generalised thorotrastosis after retrograde pyelography (author's transl)].

A 70 years old patient is presented who was nephrectomized because of carcinoma of the kidney following retrograde pyelography with Thorotrast in 1940. Despite of local application of the contrast medium thorotrastosis was also seen in liver, spleen and probably in bone marrow. Possible causal connections are discussed. Thorium was identified in the kidney and in the liver with an electron beam microprobe.

Aged↗