Acute Toxicity of 14 Different Kinds of Metals Affecting Medaka Fry

We examined the acute toxicity of 14 different kinds of metals affecting medaka fry and from the results, arranged them according to the order of intensity level of acute toxicity. The most toxic metals to medaka fry were Ag, Hg, Cu, and Cd, the second most toxic were Zn, As, Cr, Ni, and Pb, and the third most toxic were Se, V, Fe, and Co. The metal least toxic to medaka fry was Mn

Comparison of the virulence of exopolysaccharide-producing Prevotella intermedia to exopolysaccharide non-producing periodontopathic organisms

<p>Abstract</p> <p>Background</p> <p>Evidence in the literature suggests that exopolysaccharides (EPS) produced by bacterial cells are essential for the expression of virulence in these organisms. Secreted EPSs form the framework in which microbial biofilms are built.</p> <p>Methods</p> <p>This study evaluates the role of EPS in <it>Prevotella intermedia </it>for the expression of virulence. This evaluation was accomplished by comparing EPS-producing <it>P. intermedia </it>strains 17 and OD1-16 with non-producing <it>P. intermedia </it>ATCC 25611 and <it>Porphyromonas gingivalis </it>strains ATCC 33277, 381 and W83 for their ability to induce abscess formation in mice and evade phagocytosis.</p> <p>Results</p> <p>EPS-producing <it>P. intermedia </it>strains 17 and OD1-16 induced highly noticeable abscess lesions in mice at 10⁷colony-forming units (CFU). In comparison, <it>P. intermedia </it>ATCC 25611 and <it>P. gingivalis </it>ATCC 33277, 381 and W83, which all lacked the ability to produce viscous materials, required 100-fold more bacteria (10⁹CFU) in order to induce detectable abscess lesions in mice. Regarding antiphagocytic activity, <it>P. intermedia </it>strains 17 and OD1-16 were rarely internalized by human polymorphonuclear leukocytes, but other strains were readily engulfed and detected in the phagosomes of these phagocytes.</p> <p>Conclusions</p> <p>These results demonstrate that the production of EPS by <it>P. intermedia </it>strains 17 and OD1-16 could contribute to the pathogenicity of this organism by conferring their ability to evade the host's innate defence response.</p

水質汚濁指標としてのメダカの脊椎骨異常の特性

We exposed red medaka at different developmental stages to various levels of cadmium,　zinc, oxadiazon emulsion and fenitrothion emulsion to determine whether these fish　represent useful biological indicators of water quality. We found that the incidence of　vertebral abnormalities was the highest when eggs or newly hatched fry were exposed　to the heavy metals or agricultural chemicals, that the chemicals exerted a greater　adverse effect on the vertebral structure of medaka than did the examined metals, and　that the centrum is the most sensitive vertebral indicator of induced damage. Our　results suggest that medaka represent useful biological indicators of water quality

The Effects of Fenitrothion Emulsion (Organic Phosphorous Pesticide) and Its Degraded Solution on Mice

Experiments were carried out to examine the effects of degradation products on mice. Fenitrothion (MEP) emulsion, a kind of an organic phosphorous insecticide, adjusted to pH 8, pH 10, and pH 14 were degraded by exposure to natural sunlight. Physiological saline, an untreated MEP emulsion, and the three degraded solutions were prepared as experimental chemicals and were administered subcutaneously at a dosage of 0.1 ml/10 g body weight (BW) into the backs of pregnant mice once a day, from the 3rd to the 15th fetal day. Each dose included 20, 40, or 90 mg/kgBW of MEP and several degradation products of MEP. LD50 was determined according to Behrens' method. The mean fetal body weights of 18th day of pregnancy in 40 and 90 mg/kgBW of MEP of the pH 8 degraded solution were 1.09 and 1.16 g, respectively, significantly lower than that of untreated MEP emulsion (1.27 g). Further, LD50 values of the three kinds of degraded solutions were 60-120 mg/kgBW, much lower than that of the untreated MEP emulsion (410 mg/kgBW). These results indicate that the degradation products of MEP emulsion degraded by the exposure of sunlight have an influence on both adult and fetal mice.This study was supported by a Grant-in-Aid for General Scientific Research from the Ministry of Education, Science, and Culture

Effects of a Diphenyl Ether Herbicide (CNP Emulsion) on Mouse Fetuses

We investigated the effects of a diphenyl ether herbicide, a chlornitrophen (CNP) emulsion, on mouse fetuses. An MO emulsion was used as the experimental chemical twenty percent of this herbicide consisting of CNP. CNP and other components were extracted and evaporated (undegraded solution). The chemical was diluted 10 times by deionized water and then exposed to sunlight until the CNP concentration in the mixture became 10% of the initial CNP concentration. CNP, degradation products, and other materials were extracted from the mixture and evaporated (degraded solution). The undegraded and degraded solutions were administered subcutaneously to the backs of pregnant mice from the 6th to 15th fetal day, once daily. The mice were sacrificed on the 18th day of pregnancy. The number of fetuses and implantations, their weights, externals and skeletons were observed. Infant mice born from maternal mice treated in the same way as above were weighed once a week. Mean fetal body weights of the undegraded and degraded solution dose groups were significantly lower than those of the control (p < 0.001). Fetal skeletal abnormalities were also higher than those of the control. The degraded solution dose group differed particularly in this regard from the control (p < 0.05). In the degraded solution dose group, all 21 newborn infants from two maternal mice out of a total of 43 newborn infants from four maternal mice died within one week. The above results suggest that the degraded solution of CNP is no less noxious on mouse fetuses than the undegraded solution. Thus, more consideration should be given not only to the original chemicals but to the degradation products as well when assessing agricultural control chemicals for their safety.This study was supported by a Grant-in-Aid for General Scientific Research from the Ministry of Education, Science, and Culture of Japan (63570238)

A Study on the Connected Items of Smoking Habit in Youth and Its Countermeasures

In order to find out the connected items of smoking habit and to consider its countermeasures of smoking, a questionnaire survey was carried out in July 1985 to 1451 1st- and 2nd-grade college or university students. The percentages of students who were currently smoking and who smoked in the past were 75.9% of male students and 35.9% of females. 40.1 % of the male students and 42.6% of the female students first smoked when in high school and 31.1 % of the male students and 28.9% of the female students when in junior high school. 60.1 % of the male students and 63.2% of the female students took on the habit of regular smoking when in high school. From an analysis according to Hayashi's quantification theory II, it was found that permissive consciousness and attitudes towards smoking, not to keep school rules and prohibition when in high school, lack of recognition of the hazardousness of smoking were items determining the smoking probability in the male students. And that indecision regarding the right to hate smoking, inability to choose a sports activity according to one's feelings were items determining the smoking probability in female students. From these results, in order to prevent youth from smoking it is most important to take countermeasures through health education such as increasing knowledge and consciousness of the effects of smoking and promoting the mental and social well-being of junior high school and high school students