Short-term exposure to high levels of natural external gamma radiation does not induce survival adaptive response

In some areas of Ramsar, a city in northern Iran, residents receive a much higher annual radiation exposure than is permitted for radiation workers. Induction of adaptive response in residents of Ramsar has been reported previously. In this study induction of such a response in short term exposure to high background levels of gamma radiation is investigated. Fifty male NMRI mice were randomly divided into four groups of 10-17 animals and 53 Wistar rats were randomly divided into five groups of 10-12 animals were studied. Animals in the 1[st] group were kept for 7 days in an outdoor area with normal background radiation while the 2[nd], 3[rd], 4[th] and 5[th] [in case of rats] groups were kept in 3 different outdoor areas with naturally elevated levels of gamma radiation. Animals were then exposed to a lethal dose of 8 Gy gamma radiation. For mice, 30 days after exposure to lethal dose, the survival fraction for the control group was 40% while the 2[nd], 3[rd], and 4[th] groups had survival rates of 20%, 33.30%, and 35.20%, respectively. For rats, 30 days after exposure to the lethal dose, the survival fraction for the control group was 40% while the 2[nd], 3[rd], 4[th] and 5[th] groups had survival rates of 20%, 41.6%, 60.0% and 35.7%, respectively. Results indicate that short term exposure to extremely high levels of natural gamma radiation [up to 196 times higher than the normal background] do not lead to induction of survival adaptive response

[Genotoxic effect of hydrogen peroxide on bone marrow erythrocytes of female Balb/C mouse]

Hydrogen peroxide is a strong oxidant which is being widely used in hairdresser places. Genotoxic effect of such substances, referred to as "interaction between gene and environment, is one of the most worrying problems of international health society. On the basis of the wide use of hydrogen peroxide, its capability on induction of chromosomal damages on polychromatic erythrocytes of bone marrow of exposed female Balb/C mice was investigated. The female Balb/C mice were used as experimental model. The mice were divided to three different groups including: control, Sham-exposed and experimental groups. The experimental group was exposed to inhalation of 9% oxidant vapor, containing hydrogen peroxide, for 2 and 3.5 hours per day for 7 days. Bone marrow cells of exposed as well as control and sham-exposed mice were collected using FCS, and micronucleus assay was performed. The chromosomal aberration was investigated by scoring the micronucleus containing polychromatic erythrocytes. The data was statistically analyzed by t-test. The results showed that mean No. of polychromatic erythrocytes in sham-exposed 1 and treated 1 [2 hours exposure to H2O2] were 8.87 +/- 1.01 and 5.75 +/- 3.05 respectively [P<0.05], and sham-exposed 2 and treated 2 [3.5 hours exposed to H2O2] were 8 +/- 2.36 and 42.37 +/- 4.8 respectively [P<0.01]. Also increasing the exposure treatment time with H2O2 could increase the chromosomal abnormality [P<0.05]. Results of this study revealed the genotoxic effects of inhalation of 9% H2O2 on bone marrow cells of female Balb/C mouse

[ periodontal condition, delivery time and infant weight in pregnant women aged 18-35 years old refered to Hedayat and Mahdiyeh hospitals in Tehran, 2004]

The previous studies in various populations demonstrated different results for the relationship between periodontal disease and adverse pregnancy outcomes. The aim of this preliminary study was to evaluate the periodontal condition and pregnancy outcome of pregnant women in two hospitals in Tehran. 150 pregnant, 18-35 years old women in their 21-24 weeks of gestation participated in this study. Informed consent obtained and general information including age, weight, smoking, educational level, systemic disease, medications and number of previous pregnancies were collected. Periodontal examinations, including plaque index, bleeding on probing, pocket depth and attachment level were recorded. Finally the pregnancy outcome including gestational age and birth weight at delivery time collected and recorded. The rate of premature delivery and low birth weight infants in this study was determined and was considered 95% in the whole population. Chi-Square test was used to determine the correlation between periodontal parameters and premature delivers and low birth weight infants. The incidence of preterm low birth weight was 12.1%, but no significant relationship between the presences or severity of periodontal disease and pregnancy outcome were noticed in this population. Well-designed case-control studies are needed to evaluate the relationship between the periodontal disease and the pregnancy outcome in Iranian population