Ionizing radiation accelerating aging and neurodegeneration

Author: D.A. Bazyka, S.V. Volovik, K.G. Manton et al.

Reference: International Journal of Psychophysiology. — 2004. — Vol. 54, № 1–2. — P. 118–119.

Involvement of the central nervous system in radiation-induced multi-organ dysfunction and/or failure

Author: P. Gourmelon, C. Marquette, D. Agay et al.

Reference: BJR. ― 2005. ― Suppl., 27. ― P. 62–68.

Keywords: Multiple organ failure, systemic inflammatory response syndrome, ARS

Abstract: The presence of multiple organ dysfunction syndrome (MODS) in victims of the recent accidents in Nesvizh and Tokai-mura suggests that radiation-induced systemic inflammatory response syndrome (SIRS) occurs in acute radiation sickness (ARS). Multiple organ failure (MOF) refers to the gradual and sequential failure of organs occurring after a wide spectrum of insults. MOF is believed to be the consequence of the host’s response to the insult and is strongly linked to SIRS. It is believed that SIRS is mediated by endogenous regulators that are released during the acute phase reaction. The resulting interplay of cytokines may compromise homeostasis of various organ systems, resulting in MODS. In the classical description of ARS, the role of the central nervous system (CNS) has been underestimated. Today, it is recognised that the CNS is a radiosensitive organ whose degree of dysfunction can be quantified by electrophysiological, biochemical and/or behavioural parameters. Abnormalities in CNS function defined by these parameters may occur at a low dose of whole body radiation. The evolving concept of radiation-induced MODS in ARS provides a framework for evaluating injury to the CNS. Ionising radiation also induces an inflammatory response that may be specific to the CNS. This response is observed after either local irradiation of the CNS or whole body irradiation. The relationship between inflammatory responses in the CNS and the peripheral nervous system is undefined. Whether or not the CNS inflammatory response syndrome is a consequence of SIRS or is an independent syndrome remains an open question. The answer to this question may have implications regarding therapy and medical management of irradiated victims.

URL: http://www.ncbi.nlm.nih.gov/pubmed/15975874

Intelligence and brain damage in children acutely irradiated in utero as a result of the Chernobyl accident

Author: A.I. Nyagu, K.N. Loganovsky, T.K. Loganovskaja et al.

Reference: KURRI-KR-79. — Recent Research Activities about the Chernobyl NPP Accident in Belarus, Ukraine and Russia / T. Imanaka (Ed.). — Kyoto: Research Reactor Institute, Kyoto University, 2002. — P. 202–230

Keywords: neurophysiology, neuropsychiatry, prenatal exposure, behavioral and emotional disorders

Abstract: The objective of the study was psychometric, neurophysiological and neuropsychiatric characterisation of acutely prenatally irradiated children. 100 randomly selected children who were in utero (born between April 26th, 1986 and February 26th, 1987) at the time of the Chernobyl accident and their mothers evacuated to Kiev as well as 100 classmates of the children were examined by the Wechsler Intelligence Scale for Children (WISC), electroencephalography (EEG) and clinical methods at the age of 10–12 years old. Foetal doses in the acutely exposed group were 11–92 mSv, in the comparison group — 0–3 mSv; foetal thyroid doses — 0.2–2 Gy and 0–0.04 Gy, respectively. The acutely exposed group showed a lower mean verbal IQ than in the comparison group (105.3±13.1 vs.118.1±13; p < .001) and a lower mean full scale IQ (112.1±15.4 vs. 120.9±11.5; p < .001). In addition the followings were observed in the acutely exposed group; WISC performance/verbal discrepancies with verbal decrements; a higher frequency of low-voltage and epileptiformal EEG-patterns and left hemisphere lateralised dysfunction; an increase (p < .001) of δ- and β-power and a decrease (p < .001) of θ- and α-power; an increased frequency of paroxysmal and organic mental disorders, somatoform autonomic dysfunction, disorders of psychological development, and behavioural and emotional disorders. Cerebral dysfunction was etiologically heterogeneous. This study suggests that prenatal irradiation at a thyroid foetal dose range of 0.2–2 Gy and a foetal dose of 11–92 mSv can result in detectable brain damage.

URL: http://www.rri.kyoto-u.ac.jp/NSRG/reports/kr79/KURRI-KR-79.htm

Intellectual development of children exposed to radioactive iodine after the Chernobyl accident in utero and at the age under 1.5 years

Author: S. Bazyltchik, V.M. Drozd, Chr. Reiners, Yu. Gavrilin

Reference: International Journal of Radiation Medicine. — 2001. — Special Issue 3, № 1–2. — P. 15.

Antenatal exposure following the Chernobyl accident: neuropsychiatric aspects

Author: Igumnov S.A., Drozdovitch V.V.

Reference: International Journal of Radiation Medicine. — 2004. — Vol. 6, № 1–4. — P. 108–115.

Keywords: contaminated areas, slightly contaminated areas, neuropsychiatry and psychological examinations

Abstract: Ten years follow-up investigation of intellectual development of 250 persons from Belarus exposed in utero following the Chernobyl accident and a control group of 250 persons from non- and slightly contaminated regions has been conducted. Neuropsychiatry and psychological examinations were performed among persons of both groups at the age of 6-7, 10-12,and 15-16 years. Mean antenatal internal dose to thyroid arising from the intake of 131I among persons of exposed group is 390±550 mGy (maximal dose – 4100 mGy),in control group – 35±65 mGy. Mean antenatal external dose among persons of exposed group is 10±13 mGy,maximal dose – 91 mGy. At the age of 6-7 years the persons in the exposed group had a mean Full Scale IQ lower than the control group (89.6±10.2 vs 92.1±10.5,p=0.007). At the age of 10-12 years there was no statistically significant difference between the two groups (94.3±10.4 vs 95.8±10.9,p=0.117).

Positive dynamics of intellectual development in persons of both groups has been observed up to age of 15-16 years (98.7±10.2 è 99.5±10.5,p=0.171). No statistically significant correlation was found in exposed group between individual thyroid dose as well as individual antenatal external dose and IQ at the different ages. In both groups we notice a positive moderate correlation between IQ of persons and the educational level of their parents. We conclude that probably a significant role in the genesis of borderline intellectual functioning and emotional disorders in the exposed group of persons was played by unfavorable social-psychological and social-cultural factors. (full text in English and Russian available on web)

URL: http://www.mns.gov.ua/files/rm/PDF/6_16.pdf

The intellectual development, mental and behavioural disorders in children from Belarus exposed in utero following the Chernobyl accident

Author: Igumnov S., Drozdovitch V.

Reference: Eur. Psychiatry. — 2000. — Vol. 15. № 4. — P. 244–253.

Keywords: thyroid dose, IQ, mental and behavioural disorders

Abstract: The study examined psychological development in 250 children at the age of 6-7 and 10-12 years who had been exposed in the prenatal period at the time of the Chernobyl accident in 1986. These children were compared to a control group of 250 children of the same age from non- and slightly contaminated areas of Belarus. The examination included psychiatric examination and intellectual assessment as well as the estimation of thyroid exposure in utero. The mean value of thyroid doses from (131)I 0.39 Gy was estimated for the prenatal exposed children. The children of the exposed group had a lower mean full-scale IQ compared to the control group (89.6 +/- 10.2 vs 92.1 +/- 10.5 at the age of 6-7 years, P = 0.007; and 94. 3 +/- 10.4 vs 95.8 +/- 10.9 at the age of 10-12 years, P = 0.117). Average IQ for the subgroup of highly exposed children (thyroid doses more than 1 Gy) was lower in comparison with average IQ for the whole exposed group (85.7 +/- 6.4 vs 89.6 +/- 10.2 at the age of 6-7 years, P = 0.014; 89.1 +/- 7.1 vs 94.3 +/- 10.4 at age 10-12 years, P = 0.003). No statistically significant distinctions in average IQ were found between the different subgroups of children in relation to the gestational age at the time of the Chernobyl accident. We notice a positive moderate correlation between IQ of children and the educational level of their parents (in exposed group – mothers: r = 0.50, P < 0.01 and fathers: r = 0.52, P < 0.01; in control group – mothers: r = 0.41, P < 0.05 and fathers: r = 0.42, P < 0.05). There was a moderate correlation between high personal anxiety in parents and emotional disorders in children (for mothers r = 0.38, P < 0.05; for fathers r = 0.43, P < 0.01). The relative risk of mental and behavioural disorders has been estimated for emotional disorders OR = 2.67, P < 0.001. The frequency of the formation of mental retardation, hyperkinetic disorders and other mental and behavioural disorders in children from both groups was approximately the same. We conclude that in the genesis of borderline intellectual functioning and emotional disorders in the exposed group of children a significant role was probably played by unfavourable social-psychological and sociocultural factors such as a low educational level of the parents, the break of microsocial contacts and difficulties adapting, which appeared following the evacuation and relocation from the contaminated areas.

URL: http://www.ncbi.nlm.nih.gov/pubmed/10951608

The brain bioelectric activity of the Belarusian persons irradiated in utero as a result of Chernobyl accident

Author: Igumnov S.

Reference: Activitas Nervosa Superior Rediviva. — 2009. — Vol. 51, № 1–2. — P. 55–60.

Keywords: BEA, Belorus, borderline EEG, IQ

Abstract: OBJECTIVE: The study examined the formation of bioelectric activity (BEA) of the brain of 250 children at the age of 6–7, 10–12 and 15–16 years from regions highly contaminated by Chernobyl fallout, who were irradiated in the prenatal period at the time of the Chernobyl accident in 1986. These children were compared with a control group of 250 children of the same age from non-contaminated areas of Belarus.

METHODS: The examination included visual and computerized analysis of EEG as well as psychiatric examination and assessment of intellectual level.

RESULTS: In the both groups of children at the age of 6–7 the dominant were the variants of age norms (46.4% vs 44.8%; p=0.592) and synchronized (borderline) EEG (26.4% vs 28.0%; P=0.763). Quite noticeable was the relevant frequency of the slow type of EEG (19.2% vs 18.4%; p=0.820) as well as paroxysmal activity (8.0% vs 8.8%; p=0.830) in the both groups. At the age of 15–16 in the both groups we registered relevant decrease of index of θ- and δ-activity. The slow type of EEG in most cases was transformed into the age norm and synchronized type of EEG. The correlation analysis showed that the intellectual level of children (IQ) estimated by Wechsler Intelligence Scale (WISC-III) was in the direct proportion to spectral power of α-diapason in frontal lobes of the brain (r=0.38 in the both groups). Mental deficiency of children of the both groups was accompanied by the decreased level of the coherency of α-diapason. When comparing the results of BEA research with the dosimetric data we found no relevant correlation of these indices. The children with different EEG types did not demonstrate any relevant differences of medium doses of antenatal exposure.

CONCLUSIONS: The revealed changes of BEA of the brain show distinct age dependency. Their frequency in the cohort of persons exposed to antenatal irradiation did not have relevant differences from that in control group. (full text available on web)

URL: http://www.rediviva.sav.sk/51i12/55.pdf

ICRP Publication 90. Biological effects after prenatal irradiation (embryo and fetus).

Reference: — Amsterdam: Elsevier (Pergamon), 2003. — 230 p.

Keywords: pre-implantation, organogenesis, and fetogenesis, animal study

Abstract: In its 1990 recommendations, the ICRP considered the radiation risks after exposure during prenatal development. This report is a critical review of new experimental animal data on biological effects and evaluations of human studies after prenatal radiation published since the 1990 recommendations.

Thus, the report discusses the effects after radiation exposure during pre-implantation, organogenesis, and fetogenesis. The aetiology of long-term effects on brain development is discussed, as well as evidence from studies in man on the effects of in-utero radiation exposure on neurological and mental processes. Animal studies of carcinogenic risk from in-utero radiation and the epidemiology of childhood cancer are discussed, and the carcinogenic risk to man from in-utero radiation is assessed. Open questions and needs for future research are elaborated.

The report reiterates that the mammalian embryo and fetus are highly radiosensitive. The nature and sensitivity of induced biological effects depend upon dose and developmental stage at irradiation. The various effects, as studied in experimental systems and in man, are discussed in detail. It is concluded that the findings in the report strengthen and supplement the 1990 recommendations of the ICRP.

URL: http://www.icrp.org/publication.asp?id=ICRP%20Publication%2090

ICRP Publication 49. Developmental effects of irradiation on the brain of the embryo and fetus / A report of a Task Group of Committee 1 of the International Commission on Radiological Protection, 1986

Reference: Annals of the ICRP. — Oxford: Pergamon Press, 1986. — 43 p.

URL: http://www.icrp.org/publication.asp?id=ICRP%20Publication%2049

Effects of ionizing radiation on behavior

Author: Hunt W.A.

Reference: Military radiobiology / J.J. Conklin, R.I. Walker (Eds.). — San Diego: Academic Press, Inc., 1987. — P. 321–330.