ABSTRACT
The induction of micronucleated reticulocytes in the bone marrow is a sensitive indicator of chromosomal damage. Therefore, the micronucleus assay in rodents is widely used in genotoxicity and carcinogenicity testing. A test system based on cultured human primary cells could potentially provide better prediction compared to animal tests, increasing patient safety while also implementing the 3Rs principle, i.e. replace, reduce and refine. Hereby, we describe the development of an in vitro micronucleus assay based on animal-free ex vivo culture of human red blood cells from hematopoietic stem cells. To validate the method, five clastogens with direct action, three clastogens requiring metabolic activation, four aneugenic and three non-genotoxic compounds have been tested. Also, different metabolic systems have been applied. Flow cytometry was used for detection and enumeration of micronuclei. Altogether, the results were in agreement with the published data and indicated that a sensitive and cost effective in vitro assay to assess genotoxicity with a potential to high-throughput screening has been developed.
Subject(s)
Erythrocytes/drug effects , Hematopoietic Stem Cells/cytology , Mutagens/toxicity , Cells, Cultured , Coculture Techniques , Humans , Micronucleus TestsABSTRACT
The diagnosis of acute myocarditis in children is based on histological criteria. Often viral in origin, it results in acute left ventricular dysfunction, the clinical manifestations of which are very variable. The potential severity of the disease is maximal in its initial phase, justifying rapid and intensive treatment. Long-term outcome is relatively good although there is a risk of chronic left ventricular dysfunction. This retrospective study is based on 11 cases of acute myocarditis admitted to the paediatric unit of Clermont-Ferrand University Hospital between February 1989 and March 1999. The initial symptoms were non-specific. Echocardiography was the key diagnostic procedure. Half of the patients had severe cardiac failure requiring admission to the intensive care unit. Four cases presented with a severe complication: two embolic events, one syncopal atrioventricular block and one cardiac arrest. The cardiac treatment was classical (digitalis, diuretics, angiotensin converting enzyme inhibitors, anticoagulants). The aetiology was established in 3 cases (toxoplasmosis, haemolytic and uraemic syndrome, Kawasaki) and a viral cause was suspected in 6 other cases (adenovirus in 3 cases, herpes virus, RSV and enterovirus in 1 case). There were no deaths in the acute phase. The long-term outcome was globally good: complete regression in 8 cases, 1 chronic left ventricular dysfunction and 2 late deaths due to intractable cardiac failure. This short series illustrates the often misleading presentation of acute myocarditis in childhood, the value of systematic investigation in the hope of a specific treatment becoming available in the near future for the often viral aetiology.
