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H Tamamoto

Publications and source records attributed to H Tamamoto.

6 recordsLinked to original sources
PubMed2003

Evaluating bioaccumulation of suspected endocrine disruptors into periphytons and benthos in the Tama River.

There are two major routes through which fish are exposed to endocrine disruptors (EDs); one route is through water that is a habitat; the other is through aquatic food such as algae and benthos. Few studies on the bioaccumulation of EDs in food have been conducted. Therefore, we evaluated the concentration in food of nonylphenol (NP), bisphenol A (BPA) and 17beta-estradiol (E2), which were frequently detected in river water and in final discharge of Wastewater Treatment Plants (WWTPs) in Japan. We also evaluated the estrogenicity of samples using recombinant yeast. NP concentrations ranged 0.1-0.4 microg/L in the river water, while they ranged 8-130 microg/kg-wet in the periphytons and 8-140 microg/kg-wet in the benthos. BPA concentrations ranged 0.02-0.15 microg/L in the river water, while they ranged 2-8.8 microg/kg-wet in the periphytons and 0.3-12 microg/kg-wet in the benthos. E2 concentrations ranged 0.0001-0.0076 microg/L in the water, while they ranged 0.09-2.26 microg/kg-wet in the periphytons and <0.01-0.22 microg/kg-wet in the benthos. The estrogenicity ranged 0.0001-0.0464 microg-E2equivalent/L in the water, while it ranged 3.4-66.8 microg-E2equivalent/kg-wet in the periphytons and 7.4-5458 microg-E2equivalent/kg-wet in the benthos. Bioaccumulation factors of NP are estimated as 160-650 for the periphytons, and 63-990 for the benthos, respectively. Bioaccumulation factors of BPA are estimated as 18-650 for the periphytons, and 8-170 for the benthos, respectively. Bioaccumulation factors of E2 are estimated as 64-1,200 for the periphytons, and 100-160 for the benthos, respectively. The ratios of the periphytons and the benthos to the water in terms of the estrogenicity were larger than those in terms of the chemicals. In particularly, the ratio of the benthos to the water is about 10(6) in the maximum. The results suggest that food may be a more important route for fish exposed to EDs in water environment.

Animals↗
PubMed2003

Study of estrogenic effects on carp (Cyprinus carpio) exposed to sewage treatment plant effluents.

To investigate whether male carp (Cyprinus carpio) are really feminized by estrogen-like substances in effluent from sewage treatment plants (STPs) in Japan, exposure tests were performed using carp in water tanks that were receiving effluent from a STP. During eight weeks of exposure, we had measured their serum vitellogenin (VTG), a precursor of yolk protein specific for females that is synthesized in their liver by estrogen-like substances and that is, therefore, a biomarker of feminization. For this research, a STP with representative effluent estrogenic activity level was selected. In the first run of the tests that launched in the early spring of 2000, male carp were exposed. Results showed that the VTG concentration in male carp exposed to the effluent increased with time, while it was reduced after exposure to the effluents was stopped and the exposure was changed to dechlorinated tap water. On the other hand, in the control experiment, VTG was not detected in male carp exposed to dechlorinated tap water. Therefore, male carp might be reversibly feminized by the STP effluent. To assure whether the feminization of male carp was caused by the STP effluent at any time, two more runs of the test were performed in the summer of 2000 and February to April of 2001. However, significant level of VTG in male carp could not be observed for eight weeks. The estrogenic activities in the effluents were almost the same level throughout the tests; therefore the seasonal timing of exposure might be important for understanding this inconsistent phenomenon.

Animals↗
PubMed1998

Cytogenic studies of Hynobiidae (Urodela). XIV. Analysis of the chromosome of a Chinese salamander, Batrachuperus pinchonii (David).

The chromosome number of a Chinese salamander, Batrachuperus pinchonii, was re-examined Adults and embryonic specimens had a diploid number of 66, with 33 bivalents during meiosis, in contrast to previous reported results. Furthermore, when C-banding analysis was performed with embryos, chromosomes with banding patterns homoeologous to those of Salamandrella keyserlingii and Hynobius species were found. It appears, therefore, that Batrachuperus, Salamandrella and Hynobius might be derived from a common ancestral species in eastern Asia.

Animals↗
PubMed1995

A simplified judgment system for medical informatics.

This report describes a new simplified judgment system which enables users to register appropriate judgment rules with ease and to apply them to a wide variety of medical problems. The rule utilized in this system is 3-AND-3-OR, quite a simple one. By applying this judgment rule to the data of as many as 60 items, judgment results of the individual on each item is given by four different grades or categories, namely: 1) normal, 2) borderline, 3) abnormal, and 4) severe. As many as 20 types can be obtained simultaneously. The simplicity of the algorithm allows medical users who are not the experts in computer technology to use this system on a DOS-based personal computer.

Algorithms↗