1981年 · 第01卷第06期

This paper describes the dosimetric considerations of the design of devices for animal irradiation and the methods of desimetry of mixed neutron-γ radiation.

For the purpose of dosage homogeneity, a cage in the shape of round plate was used. Along its radius mice or rats were arranged on its periphery. And the cage was rotating about its central axis during irradiation.

Neutron dose was deduced from the whole neutron flux spectra measured by activation method. Gamma dosimetry was performed with glass dosimeter.

The dosimetric results of three irradiation conditions, filtered by different thickness of lead and natural boron, were presented in detail.

34 estradiol derivatives have been tested in mice for their antiradiation activities. The mice were exposed to 750 rads of γ-rays. Nine days following irradiation, spleen weights, endogenous spleen colonies, peripheral leucocytes and femoral DNA contents of the treated mice were determined and compared with those of the control which were subjected to irradiation in different doses. The protective effect of the estrogens was expressed by the reduction of radiation doses in rads. The data were then fitted to a multiple linear regression analysis model by means of a computor program. Statistical tests showed that the correlation coefficient was equal to 0.97, which is in line with the additive model. The results indicated that the radioprotective effect of estradiol derivatives largely depend on the unsubstituted parent structure. This is equivalent to a reduction of radiation dose of 67 rads. The contributions attributed to 17α-ethynyl, 3-benzoyl and 3-pentoxy groups were 70, 76 and 26 rads respectively. On the contrary, the influence of the substituted groups at C-2, C-15β, C-16α or β positions invariably caused a decrease of the radioprotective effect of the parent structure.

Since the relationship between structure and antiradiation activity of estradiol derivatives is to a great extent similar to that between structure and estrogenic activity of these compounds, it seems reasonable to infer that the estrogen receptor may also play a role in radiation protection.

This paper reported 36 cases with the clinical observation of the effects of human α₂-M combined with anti-inflammatory agent and surgical intervention in the treatment of post-irradiation mucocutaneous necrosis and ulceration, poor healing of operative incision in the area of radiotherapy, rectal reaction accompanied by mucous ulceration and bleeding of the uterine cervix carcinoma after radiotherapy and other tissue damages after radiotherapy.

The pharmacotherapy was highly effective in 11 cases and moderately effective in 16 cases, the total effectiveness being 27/36. The therapeutic effect was excellent in poor healing of operative incision in the area of radiotherapy. There was no side-reaction, allergy or hypersensitiveness. The general symptoms were improved and the appetite was increased. Besides, it had an analgesic effect. It is a new remedy for non-surgical treatment of stubborn radiation ulcer.

In consequence of exploitation of nuclear energy and rising amounts of tritium-labelled compounds used in industry, agriculture, medicine, biology and research a growing number of people must be controlled for tritium incorporation. In order to decide whether incorporation by occupationally exposed persons took place, it is necessary to look for natural background levels. In this paper investigations have been carried out to get some information about tritium concentrations in urine of non-occupationally exposed persons from a region in Sichuan, China.

A combined anion exchange-spcctrophotometric method with arsenazo Ⅲ has been developed for the determination of thorium in coal cinder bricks.

At first, the building material sample in a teflon beaker is decomposed with a mixture of perchloric and hydrofluoric acids by heating. Heating to dryness with hydrofluoric acid is repeated, and the residue is dissolved and heated to dryness with sulfuric acid, hydrochloric acid and nitric acid successively. Finally, the residue is dissolved in 15 ml of 6.6N nitric acid. This solution passes through a column of strong anion exchange resin 201×7 (NO₆-form) in order to eliminate interference elements, and the thorium is adsorbed quantitatively on the column. Then, thorium is stripped by elution with 30ml of 0.1N nitric acid and then determined spectrophotometrically with arsenazo Ⅲ in 4N hydrochloric acid solution.

Thorium content in thorium reference source (powder) supplied by the Third Beijing Research Institute is determined with the proposed procedure. The result is identical with the given content in reference source. Thorium in coal cinder bricks is also determined with the proposed procedure, and the rate of recovery regularly reaches 95% or over.