Effect of tritium on embryo and fetuses in rodents

在HTO对小鼠的致癌作用研究中，3.6m Gy/d的HTO可使小鼠寿命缩短，但在HTO浓度越低的情况下，未观察到肿瘤发生、辐射体征、寿命缩短的证据。HTO与MNU联合治疗雌性SD大鼠，HTO治疗组乳腺肿瘤未增加，但HTO明显增加了肿瘤的发展。为了确定HTO的相对生物学有效性，我们进行了肠隐窝干细胞实验，结果显示60 m Ci/小鼠HTO没有杀死BCF_1小鼠，这与以往的报道相比具有较高的价值。氚气体对新生婴儿没有太大影响，但对后半部分胎儿的伤害是前半部分胎儿的两倍。在胚胎胎儿中，HTO引起的损伤似乎是独特的，但其特征正在仓鼠胚胎中进行研究。这组对大脑发育的影响刚刚开始，主要观察是分析睁眼、跑动和神经肽的变化。以5cgy的HTO剂量，与20cgy的γ射线剂量产生同义性征象。通过5 cGy的HTO预处理，体外暴露于不同剂量γ射线的白血病细胞突变频率降低。在人类白血病细胞系中，引入Fish技术来鉴定由伽马射线引起的明确标记物。用这种方法分别鉴定了14天的髓样细胞和40天的淋巴样细胞的新标记物。接受lac Z基因的Ingeno小鼠正在开发和建立中，引入我们的实验将开辟新的途径。

In carcinogenesis study of HTO in mice, 3.6m Gy/day induced life-shortening, but no evidence was observed on the incidence of tumor development, hormetic sign, life shortening under the more lower HTO concentrations. By a combined treatment of HTO and MNU in female SD rats, there were no increase of mammary tumors in HTO treated group, but significant increase of tumor development was observed by HTO.To identify the relative biological effectiveness of HTO,stem cell assay of intestinal crypt was done and 60 m Ci/mouse HTO did not kill the BCF_1 mice, which is rather high value compare to the previous report. Tritium gas did not influence too much to the newborn babies, but it gave twice as much as of damage to the latter half of fetuses compared to the former half of fetuses. In embryonic fetuses, the damage caused by HTO seemed to be unique, but its characterisric are under investigation by Hamster's embryo. Influence on the brain development is just started in this group, and its main observation is to analyze eye-opening, running and changes of neuropeptides. By the dose of 5 c Gy of HTO,it induces synony-mous signs to the dose of 20 cGy of gamma ray. By pre-treatment of 5 cGy of HTO,leukemiccells in vitro exposed to various doses of gamma-ray showed decreased mutation brequency. In human leukemic cell lines, Fish technique was introduced to identify the definite markers caused by gamma-rays. By this method, 14 day of myeloid cells or 40 days of lymphoid cells were identified of respective new markers.Ingeno mice receiving lac Z genes are under development and establishment and introduction to our experiment should open new avenue.