title: Analysis of primary processes in the foramtion of acentric fragments.
abstract: An analysis of primary processes in the formation of excess acentric fragments in human lymphocytes was carried out in experiments with 220 kV X-rays after acute exposure (D = 50 R/min, 25--400 R) and fractionated exposure (340 R split into two equal fractions, separated by intervals between 50--360 min). Chromosome analyses occurred after conventional staining. Applying G-banding data from an acute X-irradiation experiment representative dose-effect curves for acentrics could be established which take into account one-break and two-break events in the formation of this aberration type. For the time dependent primary breaks necessary for the formation of two-break two-track acentrics a mean interaction time t approximately = 102 min could be calculated. This is well in line with the corresponding time t approximately = 110 min for dicentrics. The distribution of acentrics among cells shows the phenomenon of overdispersion.
mesh_terms: D002869:Chromosome Aberrations; D002871:Chromosome Banding; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000528:radiation effects*; D014965:X-Rays