Cytogenetic dosimetry by micronucleus assay using peripheral blood cells is modified by thyroid hormones

Cytokinesis-block micronucleus (CBMN) assay is a convenient and easy method of radiation biodosimetry that uses peripheral blood (PB) cells. However, for micronuclei (MN) frequency induced by ionising radiation, a dose-response relationship in abnormal condition, such as in cancer patients, has not been assessed. To clarify the difference between the dose-response curve generated by the CBMN assay in conditions when thyroid hormone levels were normal and during thyroid hormone withdrawal (THW) prior to (131)I treatment, 12 thyroid cancer patients who underwent thyroidectomy were studied. The collected PB mononuclear cells were exposed to 0.5-3.0 Gy X-ray irradiation. Under normal conditions, dose dependency and independency of MN frequency were observed in 92 % and 8 %, respectively. In contrast, during THW, the number of patients who showed dose independency significantly increased to 42 % in comparison with control. Furthermore, a higher concentration of serum thyroglobulin in dose-independent patients was observed. These results suggest that MN frequency in cytogenetic dosimetry is affected by thyroid hormones.

Radioprotective effects of (-)-epigallocatechin-3-gallate on human erythrocyte/granulocyte lineages

Epigallocatechin-3-gallate (EGCg) is widely recognised as a powerful antioxidant and free radical scavenger. This study examined the radioprotective effects of EGCg on human granulopoiesis and erythropoiesis. Highly purified human CD34(+) haematopoietic stem/progenitor cells were prepared from human placental/umbilical cord blood. The cells were exposed to X rays at a dose rate of ∼1 Gy min(-1) and then cultured in a medium supplemented with either granulocyte colony-stimulating factor (G-CSF) or erythropoietin (EPO). EGCg (100 nM) was added to the culture immediately before or after X-irradiation. The concentration of 100-nM EGCg was determined in the authors' previous study. The number of granulocyte and erythrocyte colonies generated by X-irradiated CD34(+) cells decreased in a dose-dependent manner. Although EGCg addition yielded an ∼2-fold increase in the proliferation of each haematopoietic progenitor, no significant protective effect was observed in the surviving fraction of granulocyte progenitors (G-CSF alone: D(0)=1.06 Gy, n=1.14). However, EGCg addition before or after irradiation conferred a significantly higher protective effect on erythrocyte colony formation compared with the control (EPO alone: D(0)=0.66 Gy, n=1.56; EGCg (before): D(0)=0.43 Gy, n=5.48). EGCg addition before irradiation significantly improved the survival of erythroid progenitors subjected to radiation of <1 Gy. These results suggest that EGCg is more protective of erythropoiesis than granulopoiesis from radiation damage.

[Effects of negative-sentence suggestions on various behavior]

The purpose of this study was to examine the effects of negative-sentence suggestions on various behavior. From the standpoint of the logic of negation, Miyashita (1998a, 1999) investigated the characteristics of feelings, sensations, and behavior. The results suggested that negative-sentence suggestions had more affirmative effects on mono-dimensional behavior than on multi-dimensional behavior. The present study examined this hypothesis. A total of 36 subjects (18 males, 18 females, mean age = 23.22, SD = 3.41) participated in the experiment. Subjects were given suggestions related to either mono-dimensional behavior or multi-dimensional behavior in negative-sentence form. An example of a suggestion related to mono-dimensional behavior would be "Your body does not move backwards", while an example for multi-dimensional behavior would be "Your body does not move." Body sway was then measured. Results showed that negative-sentence suggestions had more affirmative effects on mono-dimensional behavior than on multi-dimensional behavior. The hypothesis proposed by previous studies was supported.

[Effects of negative-sentence suggestions under light hypnotic states on feelings and behaviors]

The purpose of this study was to examine the effects of negative-sentence suggestions on feelings and behaviors. Feelings and behaviors were classified under the axes of pleasant-unpleasant, and low-high activity. Sixteen subjects (six males and ten females) were induced into a light hypnotic state, and were given suggestions of feelings and behaviors in negative-sentence form. Aside of the above-mentioned suggestions, suggestions of neutral feeling and behavior in affirmative-sentence form was given as baseline. The subjects were then requested to rate the effect, which was stated in affirmative-sentence form. For example, if subject was given a negative-sentence suggestion that your feelings are not sad, then subject asked to rate his feelings of sadness. The results showed that negative-sentence suggestions had affirmative effects when the rated feeling was unpleasant, regardless of its activity level. They had negative effects when the rated feeling or behavior was pleasant and low in activity.