Transepithelial Transport of Theasinensins through Caco-2 Cell Monolayers and Their Absorption in Sprague-Dawley Rats after Oral Administration

The aim of this study is to illustrate the in vivo and in vitro absorption of theasinensins B and A that are (-)-epigallocatechin-3-O-gallate (EGCG)-(-)-epigallocatechin (EGC) dimer and EGCG dimer, respectively, and their transport pathway across the intestinal membrane. Our animal study by a single oral administration to rats demonstrated the intact absorption of theasinensins into the blood system, which was estimated to be a >10-fold lower absorption amount than EGCG. The in vitro absorption study indicated that theasinensins can be transported across Caco-2 cell monolayers, while their permeability coefficients were also >10-fold lower than those of EGCG and EGC. Transport experiments using cytochalasin D or quercetin as a tight junction (TJ) modulator and a non-saturable permeation revealed that theasinensins were transported across Caco-2 cells in a TJ paracellular diffusion route. In conclusion, the dimers of condensed catechins, theasinensins B and A, can be absorbed intact into rat blood and transported across Caco-2 cell monolayers probably through a TJ paracellular pathway.     

Oxidative stress inducers potentiate 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated pre-cardiac edema in larval zebrafish

We reported the involvement of oxidative stress and prostaglandins including thromboxane and prostacyclin in pre-cardiac edema (early edema) caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). While the involvement of oxidative stress in TCDD-induced toxicity has been frequently reported, the mechanism of its action is still unclear. In the present study, oxidative stress inducers including paraquat, hydrogen peroxide (H₂O₂) and rotenone augmented early edema (edema) induced by a low concentration of TCDD (0.1 ppb) at 55 hr post fertilization (hpf), while each of them alone did not cause edema. Edema caused by TCDD plus oxidative stress inducers was almost abolished by antioxidants, an antagonist for thromboxane receptor (ICI-192,605) and an agonist for prostacyclin receptor (beraprost), suggesting that the site of action of these inducers was in the regular signaling pathway after activation of aryl hydrocarbon receptor type 2 (AHR2) by TCDD. Oxidative stress inducers also enhanced edema caused by an agonist for the thromboxane receptor (U46619), and the enhancement was also inhibited by antioxidants. Sulforaphane and auranofin, activators of Nrf2 that is a master regulator of anti-oxidative response, did not affect U46619-evoked edema but almost abolished TCDD-induced edema and potentiation by paraquat in both TCDD- and U46619-induced edema. Taken together, the results suggest that oxidative stress augments pre-cardiac edema caused by TCDD via activation of thromboxane receptor-mediated signaling in developing zebrafish. As paraquat and other oxidative stress inducers used also are environmental pollutants, interaction between dioxin-like compounds and exogenous source of oxidative stress should also be considered.     

Spontaneous adenocarcinoma with giant cell formation in the accessory sex glands in a male Sprague-Dawley rat

In this study, we report the features of an adenocarcinoma with giant cell formation spontaneously occurring in the accessory sex glands of a male 10-month-old Sprague-Dawley rat. A milky white mass was found in the region corresponding to the left seminal vesicle and the left coagulating gland. Histologically, tumor cells exhibited diverse growth patterns, including glandular/trabecular, cystic, and sheet-like growth areas. The tumor cells were pleomorphic, with round- or oval-shaped nuclei and abundant eosinophilic cytoplasm. Mitotic figures were occasionally observed. Giant cells were also prominent in the sheet-like growth area, with intracytoplasmic vacuoles containing eosinophilic material. The stroma was rich in collagen fibers and fibroblasts. Numerous inflammatory cells were observed in the glandular and cystic lumina and stroma. Immunohistochemically, the tumor cells were positive for cytokeratin AE1/AE3 and proliferating cell nuclear antigen. In the sheet-like growth area, some of the tumor cells and giant cells were positive for vimentin in the cytoplasm adjacent to the nucleus. Electron microscopy revealed that the tumor cells contained a small number of mitochondria and rough endoplasmic reticulum, and had no basement membrane or desmosome. The giant cells occasionally contained variably sized intracytoplasmic lumina and globular filamentous bodies, probably corresponding to vimentin. Considering these morphological features, the tumor was diagnosed as an adenocarcinoma with the formation of giant tumor cells originating from the male accessory sex glands.     

Detection of genetic variation among seed and seedlings ofChamaecyparis obtusa using allozyme markers

The effects of nursery practices on genetic composition and structure were studied inChamaecyparis obtusa by analyzing seeds and one-, two-, and three-year-old seedlings. Enzyme polymorphisms of the6Pgd-2, G6pd, Got, Gk, Shd-2, Pod, Dia-1, andPgm loci were used. OnlyDia-1 indicated significantly different allelic frequencies between seeds and three-year-old seedlings. Most of the genetic diversity of the parental clones in this seed orchard could be transferred to the offsprings. Genetic diversity on the basis of an average expected heterozygosity did not differ between seeds and seedlings. A slight excess of homozygotes in seeds and a significant excess of heterozygotes in seedlings of different ages to the expected panmictic proportions were found. Most of the differences in genotypic distributions among the seed and seedling stages, probably resulted from viability selection favoring outcrosses, and selective removal of inbred offsprings including self-fertilized ones prior to their transplantation in the nursery. A part of this paper was orally presented at the 107th Annual Meeting of the Japanese Forestry Society (1996).     

Liquid penetration of precompressed wood VI: Anatomical characterization of pit fractures

Pit fractures of refractory coniferous heartwoods caused by precompression in the radial direction were investigated and are discussed in terms of improved liquid penetration. Small cracks appeared at the boundary between the torus and margo, along the outer margin of the margo, and on the torus when specimens were compressed and deformation was fixed by drying. The remarkable cracks were generally observed for Cryptomeria japonica D. Don. Pseudotsuga menziesii Franco showed peculiar detachment of the torus from the pit border, and Larix leptolepis Gordon exhibited only small cracks on the torus. These fractures patterns were clearer when the precompressed specimens were recovered by water impregnation and then redried.This report was presented at the 46th Annual Meeting of the Japan Wood Research Society, Kumamoto, April 1996     

Value-per-recruit analysis of bighand thornyhead <Emphasis Type="Italic">Sebastolobus macrochir</Emphasis> caught off the Pacific coast of northern Honshu,Japan

The yield-per-recruit (YPR) analysis has been used to assess growth overfishing of exploited fish stocks. Since the ex-vessel price per weight widely depends on the size of the fish, the result of the YPR does not imply the revenue. The value-per-recruit (VPR) analysis, which is an economic expansion of the YPR analysis, was conducted for bighand thornyhead Sebastolobus macrochir caught off the Pacific coast of northern Honshu, Japan. The results showed that, for the current age at first capture (t _c = 3), the current fishing mortality (F = 0.12) was close to the optimum level. However, for the current F, optimum t _c in the VPR model was 8 years and would lead to a 47% increase compared to the current revenue. The maximum YPR was obtained at t _c = 6 years, but the revenue at t _c = 6 only gave a 20% increase in the maximum revenue. The difference was caused by the size dependency of the ex-vessel price per weight. The VPR model would generate fisheries management plans with both economical and biological consideration and would help in making general consensus of fisheries management strategies.     

Morphological changes and habitat shifts with growth of endangered floodplain fish: Possible adaptations to fluctuating environments

Adaptations that maximise food intake are dependent on food and/or habitat types. However, there have been few studies on the ability of floodplain primary freshwater fish to rapidly change their morphology, especially the internal one, to maximise utilisation efficiency of food resources in response to environmental fluctuations during their life history. We investigated morphological changes of an Acheilognathinae species (Acheilognathus longipinnis) that inhabits creeks in Japan to determine whether body shape variation correlated with environmental characteristics, including water depth, current velocity, vegetation cover and food availability. When shifting from floodwater-level to low-water-level season, the current velocity of the study area increased as the water level decreased, causing a significant increase in periphyton and a significant decline in zooplankton and phytoplankton. Concurrently, during the short period when A. longipinnis grow from the juvenile to the premature stage, changes in internal morphology, that is intestinal elongation, and changes in external morphology such as an increase of body depth were observed. In contrast, intestinal length significantly decreased in the adult stage. Our findings suggest that morphological changes between floodwater-level and low-water-level seasons associated with juvenile to premature development are an adaptation to changes in food availability due to environmental fluctuations. Additionally, the shortening of the intestine from the premature to the adult stage may be an adaptive strategy for reproduction.     

Erosion of irrigation facilities in Cambodia paddy farming region and the measures for protection

Paddy and Water Environment - This study investigates the erosion condition of irrigation earth structures and determines the measures for erosion protection in Cambodia paddy farming regions. Most...