Biomedical subjects
Publications and source records attributed to H Amano.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Dibutyltin dichloride (DBT), tributyltin chloride (TrBT) and tetrabutyltin (TeBT) were compared for their developmental toxicity and teratogenic potential following administration during the susceptible period for teratogenesis of TrBT. Pregnant rats were given either DBT or TrBT at a dose of 165 or 330 mumol kg-1 or TrBT at a dose of 330, 660, 1320, 2640 or 5280 mumol kg-1 on days 13-15 of pregnancy. Treatment with DBT at 165 and 330 mumol kg-1 caused a significant decrease in the maternal body weight gain. A significant decrease in the fetal weight occurred at 165 and 330 mumol kg-1. No significantly increased incidences of postimplantation loss or of fetuses with malformations were found following treatment with DBT. Treatment with TrBT at 165 and 330 mumol kg-1 resulted in a significant decrease in the maternal weight gain. A significant decrease in the fetal weight was found at 330 mumol kg-1. A significantly and markedly increased incidence of fetuses with cleft palate was noted in both groups treated with TrBT. Treatment with TeBT caused a significantly decreased maternal body weight gain at doses of 660 mumol kg-1 and above. A significantly increased incidence of fetuses with cleft palate was observed at a dose of 5280 mumol kg-1. It could be concluded that there is a difference in the manifestation and degree of developmental toxicity between DBT, TrBT and TeBT.
Butyltin trichloride (BT), dibutyltin dichloride (DBT) and tributyltin chloride (TBT) were compared for their developmental toxicity including teratogenic potential following administration during the susceptible period for the teratogenesis of DBT. Pregnant rats were given either BT at a dose of 1000, 1500 or 2000 mg kg-1, DBT at a dose of 10 or 15 mg kg-1 or TBT at a dose of 40 or 80 mg kg-1 by gastric intubation on days 7 and 8 of pregnancy. Although maternal toxicity occurred, as evidenced by a significantly increased maternal lethality at 1500 and 2000 mg kg-1 and decreased maternal weight gain at 1000 and 1500 mg kg-1, no significant increase in the incidences of postimplantation loss and malformed fetuses were observed after treatment with BT. Treatment with DBT resulted in a significantly lower maternal weight gain, lower fetal weight and higher postimplantation embryolethality. A significantly and markedly increased incidence of fetuses with malformations, such as exencephaly, cleft jaw, cleft lip, ankyloglossia, club foot, deformity of the vertebral column in the cervical and thoracic regions and of the ribs and ano- or microphthalmia, was observed in both groups treated with DBT. While treatment with TBT at 40 and 80 mg kg-1 caused a significantly decreased maternal weight gain and increased postimplantation embryolethality, no significantly increased incidence of malformed fetuses occurred. It could be concluded that BT, DBT and TBT are different in the susceptibility and spectrum of developmental toxicity.
The pathological findings in three cases of solid and cystic tumor (SCT) of the pancreas were compared with the nuclear DNA histogram obtained by flow cytometry. One case involved malignant SCT with liver metastases. Two of the cases were benign SCT. In the malignant SCT, cellular atypia and mitotic figures were extensively observed. The proliferation index (PI) was 25, and the DNA index (DI) was 1.65. In the benign SCT, cellular atypia and mitotic figures were rarely observed. The PI was 8 and 13, respectively, and the DI was 1.0 in both cases. The proliferative activity and the biological malignant potential of the malignant SCT were thought to be higher than those of the benign SCT.
The analgesic actions of some synthetically prepared peptides having the Tyr-D-Arg unit at the N terminal portion of met- and leu-enkephalin were measured by the intra-cisternal injection method in mice. Among them, Tyr-D-Arg-Gly-Phe (DR-4) induced the most potent naloxone-reversible analgesia and was also effective by s.c. injection. DR-4 showed the good affinity to mu-receptor, and the resistance to the enzymatic degradation.
m-Phenylenediamine (m-PDA, CAS: 108-45-2), a component of hair-dye formulations, was administered in the drinking-water to groups of female and male (C57BL/6 x C3H/He)F1 (B6C3F1) mice at concentrations of 0.02 or 0.04% for 78 wk. All the surviving mice were killed after a further 5-7 wk on untreated drinking-water, 83-85 wk after the start of treatment. Survival of the treated mice was similar to that of the corresponding controls. Body weights were significantly lower in high-dose females and males and somewhat lower in low-dose females than in the controls. The incidences of hepatocellular tumours were low to moderate in all male groups and in the control females, but the treated groups had significantly lower incidences than the controls. A few tumours of the lungs, haematopoietic organs and other organs and tissues were observed in all female and male groups. However, there were no statistically significant increases in the incidences of tumours in these organs and tissues in m-PDA-treated mice of either sex. Under the conditions of this study m-PDA showed no carcinogenic potential in either female or male B6C3F1 mice when administered in drinking-water. No non-neoplastic changes attributable to the compound were found in the treated mice, except for the deposition of brown pigment in follicular epithelial cells of the thyroid gland and in macrophages in some organs and tissues, and pigment impregnation of the bronchioli.
In our previous studies, butyl benzyl phthalate (BBP) was found to be embryolethal and teratogenic in rats. In order to extend these findings, the effects of BBP during early pregnancy on maternal parameters were examined. Pregnant rats were given dietary BBP at 2.0% on day 0 through the day of sacrifice, day 7, 9, or 11 of pregnancy. The number of corpora lutea and implantations and the incidence of preimplantation embryonic loss were comparable across all groups. The postimplantation embryonic loss on day 11 in the 2.0% BBP group was markedly higher than that in the control and pair-fed groups. Regardless of the day of sacrifice, the uterine and ovarian weights and plasma progesterone levels, except for the ovarian weight on day 7, in the 2.0% BBP groups were significantly lower than those in the control and pair-fed groups. These findings suggest that the postimplantation embryonic loss due to BBP during early pregnancy is mediated via the reduction in plasma progesterone levels, an impairment of luteal function.
The endolymph differs from all other extracellular fluids in its positive potential and in the ionic compositions in the various parts of the endolymphatic space. The endolymphatic space is surrounded by a tight neuroepithelium. The strial cells, which have a negative intracellular potential of -67 mV, generate a positive endolymphatic potential of +80 mV. The potassium ions are pumped into the endolymph by an active energy-consuming process. Intracellular ion concentrations of the marginal strial cells are 135 mM for potassium and 6 mM for sodium, which are comparable to concentrations in other epithelial cells. During anoxia or after ethacrynic acid injection potassium concentrations in the cochlear endolymph and in the marginal strial cells decrease, while sodium concentrations increase.