University of Essen FB9 Department of Genetics Universitätsstr. 5 D-45117 Essen (Germany). Chromosomal Aberrations in Blood Lymphocytes of Astronauts Principal Investigator: Prof. Dr. Günter Obe Co-Investigators: Markus Horstmann Dr. Christian Johannes.
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University of EssenFB9 Department of GeneticsUniversitätsstr. 5D-45117 Essen (Germany)
Chromosomal Aberrations in Blood Lymphocytes of Astronauts
Principal Investigator: Prof. Dr. Günter Obe
Co-Investigators: Markus Horstmann
Dr. Christian Johannes
The genetic material is mainly situated in chromosomes
Body cells contain 2x23 chromosomes (2n=46)
Cultured lymphocytes undergo mitosis which allows to prepare chromosomes and analyze them with the light microscope
Changes in the morphology of chromosomes (chromosomal aberrations, chromosome mutations) can be recognized and quantified
DNA is damaged by ionizing radiation, which
may lead to chromosomal aberrations
Chromosomal aberrations may lead to an elevated risk of cancer
Frequencies of chromosomal aberrations depend on characteristics and doses of ionizing radiation
gamma-, beta-, X-rays (low LET) alpha-, neutron rays (high LET)
Dose effect relationships for dicentrics and translocations following exposure to low or high LET radiation
(From G. Obe and A. T. Natarajan, 1999)
a: Undamaged metaphaseb: Radiation induced dicentric
chromosome (left) with fragment (top right)
centromeres in poly-
Human metaphase chromosomes “painted” with the mFISH method
(translocation between chromosomes 11 and 12)
The right chromosome shows a large inversion of its middle part whose breakpoints are indicated by dotted lines.
(White dots = centromeres)
Chromosomal aberrations in peripheral blood lymphocytes of astronauts
indicate an elevated mutagenic and carcinogenic risk due to radiation in space
Dicentric chromosomes in lymphocytes of seven MIR cosmonauts (C1-C7) before and after their last space flight (120-198 days). (Data from: Obe et al, 1997)
The frequencies of
dicentrics can be
calculated by taking
such as half-life of
The analysis of chromosomal aberrations in lymphocytes of astronauts allows to answer the following questions:
1. Is exposure to space radiation associated with mutagenic and carcinogenic risks ?
2. What radiation protection measures have to be taken to minimize risks of exposures to space radiation ?
To assess the genetic impact of ionizing radiations, blood (10-15 ml) is drawn before and shortly after flights by venous puncture
Blood cultures will be set up in our laboratory, using standard procedures
Chromosomes will be stained using procedures to assess all types of aberrations:
(1) Classical Giemsa staining
(2) Multi-color fluorescence in situ hybridization (mFISH)
(3) Multi-color banding fluorescence in situ hybridization (mBAND)
of chromosome 5
Venipuncture performed by a physician is nearly free of any risk.
Minor temporary discomfort or pain.
Hematoma associated with extravasation of blood during or following venipuncture.
Infection or thrombophlebitis resulting from venipuncture. This is infrequent in healthy persons.
The following safety precautions will be taken to mitigate any risk associated with venipuncture:
Procedure will be performed by experienced personnel.
Use of standard aseptic techniques.
Use of sterile disposable hardware.
Possible Inconveniences or Discomforts
No additional inconveniences or discomforts have been identified.