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At least 721 records · Page 40Linked to original sources
PubMed2003

Validation of the integrity of a HEPA filter system.

The objective of this study was to establish a delayed air sampling method to verify the integrity of an existing HEPA filter system in a ventilated fume hood. (238U,232Th)O2 microspheres were generated to fabricate cement nuclear fuel pellets in a HEPA-filtered hood. To comply with the air effluent concentration limits by NRC, the capture efficiency of the HEPA filter was examined. An in-line isokinetic air sampling system was installed downstream of the HEPA filter. Utilizing a gas flow proportional counter, 212Pb was used as a surrogate to indicate any possible penetration of the (238U,232Th)O2 particles through the HEPA filter. Based on the experimental results, this delayed sampling method proved to be an easy and effective way to validate the integrity of the HEPA filter.

Air Pollutants, Radioactive↗
PubMed1983

CT appearance of abdominal thorotrast deposition and Thorotrast-induced angiosarcoma of the liver.

Although the clinical and radiographic manifestations of Thorotrast and its complications have been described, the computed tomographic (CT) appearance of Thorotrast deposition in the abdomen is less well known. Thorotrast produces a characteristic opacification of the liver, spleen, and abdominal lymph nodes. We report two cases of patients with Thorotrast-induced angiosarcoma of the liver detected by CT. Computed tomography in both cases demonstrated space-occupying lesions in the liver, which were readily detectable because of distortion of the Thorotrast-produced opacification.

Aged↗
PubMed1979

The clinical features of hepatic angiosarcoma: a report of four cases and a review of the English literature.

Four cases of hepatic angiosarcoma are reported with a review of 99 other cases in the English literature. Angiosarcoma of the liver is associated with chronic exposure to thorotrast, vinyl chloride, arsenicals, radium and possibly copper and with chronic idiopathic hemochromatosis. Although 40% of patients have hepatic fibrosis or cirrhosis at autopsy, the nature of the association between chronic liver disease and hepatic angiosarcoma is unknown. The clinical presentation of hepatic angiosarcoma is nonspecific with abdominal pain, weakness and weight loss common complaints and with hepatomegaly, ascites and jaundice common findings. Liver function tests are usually abnormal but there is no one liver function test or set of tests specific for the tumor. The occurrence of thrombocytopenia and disseminated intravascular coagulation is characteristic of hepatic angiosarcoma and may be related to local consumption of clotting factors and formed blood elements in the tumor. Catastrophic intraabdominal bleeding is also characteristic and occurs in one-fourth of all cases. This complication is likely related to the high incidence of clotting abnormalities and the vascular nature of the neoplasm. Selective hepatic arteriogram and open liver biopsy are the foundations of diagnostic evaluation. Percutaneous liver biopsy should be avoided. Failure to appreciate the possibility of hepatic angiosarcoma in the proper clinical setting, leading to blind percutaneous biopsy, may result in failure to make the diagnosis at the cost of significant morbidity and mortality. Survival of patients with hepatic angiosarcoma is brief; only 3% live longer than 2 years. Treatment of the tumor to date is empirical. There are probably a few patients who might benefit from radical surgery with curative intent. For all others chemotherapy is indicated. Adriamycin is active against hepatic angiosarcoma, but optimal dose and mode of administration require further investigation. Further study is also required to delineate the cause of hepatic angiosarcoma in the 60% of cases without definite epidemiologic association.

Adult↗
PubMed1989

Ultrastructural studies on the intracellular fate of Chlamydia psittaci (strain guinea pig inclusion conjunctivitis) and Chlamydia trachomatis (strain lymphogranuloma venereum 434): modulation of intracellular events and relationship with endocytic mechanism.

Previous observations on the highly infectious LGV strain 434 of Chlamydia trachomatis and the guinea pig inclusion conjunctivitis (GPIC) strain of C. psittaci (which requires centrifugation of inocula with host cell monolayers for maximum infectivity) indicated that infectivity differences were expressed, not at entry, but at an intracellular stage affecting multiplication. Centrifugation increased the potential of internalized chlamydiae to undergo productive infection. Here, analysis of the intracellular fate of chlamydiae by ultrastructural methods indicates that strain GPIC exhibits two patterns of behaviour depending on the mode of inoculation. Strain GPIC showed limited entry, with 47% of intracellular organisms becoming associated with thorotrast-labelled lysosomes, following static incubation with monolayers. In contrast, with centrifugation, entry was not limited and association with lysosomes was reduced to 12%; strain 434 behaved similarly but independently of the mode of inoculation. The different results for strain GPIC correlated with distinct entry mechanisms. Entry during static incubation was unimpaired either by treatment with cytochalasin D or by temperature reduction to 20 degrees C, suggesting that it was pinocytic. Entry during centrifugation was markedly impaired by both treatments, suggesting that it was phagocytic. The data lead to two novel conclusions: first, that chlamydiae can apparently enter cells by both pinocytic and phagocytic mechanisms; second, that the entry mechanism influences intracellular fate. It is suggested that entry mechanism is linked to selection of the vesicle membrane forming around the internalizing chlamydiae. This, in turn, may influence both intracellular translocation and subsequent inhibition or promotion of multiplication of the internalized parasite.

Animals↗
PubMed1976

Thorotrast-induced haemangioendothelial sarcoma--a lesson from the past.

Complications following a carotid arteriogram done in 1947 with Thorotrast are described in a 47-year-old man who subsequently died from them in 1970. They included a local cervical granuloma with associated haemangioendothelial sarcoma, chromosome changes characteristic of radiation damage and widespread haemangioendothelial sarcomatous deposits in brain, lung, liver, probably arising from multicentric primary sites in the bone marrow. A survey of the use of Thorotrast as a contrast medium in Australia and New Zealand showed that its use was extremely limited. The prinicpal complications seen have been two cervical granulomas and one hepatoma.

Bone Marrow Diseases↗
PubMed1977

Pronounced deficiency in T-cells and lymphocyte chromosomal aberrations in a patient with sarcoidosis, myelofibrosis and acute leukaemia following thorotrast angiography.

A patient exposed to thorotrast angiography developed sarcoidosis 21 years after the injection and myelofibrosis 13 years later. On the latter occasion an extreme deficiency in circulating lymphocytes forming rosettes with sheep erythrocytes (T-cells) was observed and a large fraction of the cells had chromosomal aberrations. Acute leukaemia developed 1 year later. The multiple clinical symptoms may be related to radiation-induced destruction of bone marrow tissue, mutations in haemopoietic cells and depression of cell-mediated immunity.

Autoradiography↗