Proton-exchange mechanism of specific Cs+ adsorption via lattice defect sites of Prussian blue filled with coordination and crystallization water molecules

We have revealed the fundamental mechanism of specific Cs(+) adsorption into Prussian blue (PB) in order to develop high-performance PB-based Cs(+) adsorbents in the wake of the Fukushima nuclear accident. We compared two types of PB nanoparticles with formulae of Fe(III)4[Fe(II)(CN)6]3·xH2O (x = 10-15) (PB-1) and (NH4)0.70Fe(III)1.10[Fe(II)(CN)6]·1.7H2O (PB-2) with respect to the Cs(+) adsorption ability. The synthesised PB-1, by a common stoichiometric aqueous reaction between 4Fe(3+) and 3[Fe(II)(CN)6](4-), showed much more efficient Cs(+) adsorption ability than did the commercially available PB-2. A high value of the number of waters of crystallization, x, of PB-1 was caused by a lot of defect sites (vacant sites) of [Fe(II)(CN)6](4-) moieties that were filled with coordination and crystallization water molecules. Hydrated Cs(+) ions were preferably adsorbed via the hydrophilic defect sites and accompanied by proton-elimination from the coordination water. The low number of hydrophilic sites of PB-2 was responsible for its insufficient Cs(+) adsorption ability.

Localization of thrombospondin-1 and myofibroblasts during corneal wound repair

Thrombospondin-1 (TSP-1) is a multifunctional matrix protein that has recently been examined in various wound processes, primarily for its ability to activate the latent complex of transforming growth factor-beta (TGF-β). TGF-β has been shown to play a major role in stimulating mesenchymal cells to synthesize extracellular matrix. After injury, corneal keratocytes become activated and transform into fibroblasts and myofibroblasts. Our hypothesis is that TSP-1 regulates the transformation of keratocytes into myofibroblasts (MF) via TGF-β. In the current study, we examined the expression of TSP-1 and α-smooth muscle actin (SMA), a marker of MF, during rat corneal wound healing. Three-mm keratectomy or debridement wounds were made in the central rat cornea and allowed to heal from 8 hours to 8 weeks in vivo. Unwounded rat corneas served as controls. Expression of TSP-1, SMA and Ki67, a marker of proliferating cells, were examined by indirect-immunofluorescence microscopy. In unwounded corneas, TSP-1 expression was observed primarily in the endothelium. No expression was seen in the stroma, and only low levels were detected in the epithelium. Ki67 was localized in the epithelial basal cells and no SMA was present in the central cornea of unwounded eyes. After keratectomy wounds, TSP-1 expression was seen 24 h after wounding in the stroma immediately subjacent to the wound-healing epithelium. The expression of TSP-1 increased daily and peaked 7-8 days after wounding. SMA expression, however, was not observed until 3-4 days after wounding. Interestingly, SMA-positive cells were almost exclusively seen in the stromal zone expressing TSP-1. Peak expression of SMA-positive cells was observed 7-8 days after wounding. Ki67-expressing cells were seen both in the area expressing TSP-1 and the adjacent area. In the debridement wounds, no SMA expressing cells were observed at any time point. TSP-1 was localized in the basement membrane zone from 2 to 5 days after wounding, and the localization did not appear to penetrate into the stroma. These data are in agreement with our hypothesis that TSP-1 localization in the stromal matrix is involved in the transformation of keratocytes into myofibroblasts.

Elevated tissue concentrations of sialyl Lex-i in cancerous tissues compared with those in noncancerous tissues of various organs

Sialyl Lex-i (SLX) concentrations in the extracts of noncancerous and cancerous tissues of various human organs were determined by radioimmunoassay for detailed evaluation of SLX. Cancerous tissues had significantly elevated SLX concentrations compared with noncancerous tissues of various organs. Tissue SLX concentration of the cancerous part was significantly higher than that of the adjacent noncancerous part in the same tissue. There was no significant correlation between tissue SLX concentration and serum SLX level. Positive localization of SLX was clearly observed in such cancerous tissues by immunohistochemical study, although not in any noncancerous tissues. Each of the antigens: SLX, CA 19-9, carcinoembryonic antigen, and CA 125 showed a different distribution pattern in tissue concentration or localization in various organs. These results indicate that SLX may be a valuable cancer-associated antigen produced by malignant tissues, suggesting its clinical application as a tumor marker.

Corticoidogenic effect of acetylcholine in bovine adrenocortical cells

The effect of acetylcholine (ACh) on corticoidogenesis in primary cultured bovine adrenocortical cells was examined. One hour exposure to 10(-3) M ACh resulted in a stimulative effect on corticoidogenesis in the freshly isolated cells, and the effect of ACh grew intense during primary culture and reached the maximum on day 2. ACh showed the effect at a higher concentration than 10(-6) M. Thus the primary 2-day cultured cells were used. The corticoidogenic effect of ACh was inhibited by atropine but not by hexamethonium. The effect of ACh was dose dependent, and the extracellular Ca++ was obligatory in inducing the effect. These results suggest that the corticoidogenic effect of ACh may be due to an increase in Ca++-influx via muscarinic receptor in adrenocortical cells.

Effect of adrenaline on steroidogenesis in primary cultured bovine adrenocortical cells

In primary 2-day cultured bovine adrenocortical cells, adrenaline stimulated the steroidogenesis, while the effect of adrenaline did not appear in the freshly isolated cells. Thus the primary 2-day cultured cells were used to study the effect of adrenaline on steroidogenesis. Adrenaline showed the steroidogenesis-stimulating effect at concentrations higher than 10(-9) M, and the maximum effect was obtained between 10(-6) M and 10(-5) M in the primary 2-day cultured cells. The maximum effect of adrenaline was 50-70% of that of adrenocorticotropic hormone (ACTH). Noradrenaline, isoproterenol and phenylephrine also stimulated the steroidogenesis. However, the order of the potency was isoproterenol much greater than adrenaline = noradrenaline much much greater than phenylephrine. Propranolol and alprenolol inhibited the effect of adrenaline, but phenoxybenzamine and phentolamine did not inhibit the effect. Moreover, adrenaline stimulated the cyclic AMP production dose-dependently at concentrations higher than 10(-8) M. These results suggest that there are steroidogenesis-linked adrenergic receptors in primary 2-day cultured bovine adrenocortical cell membrane and that the steroidogenesis-stimulating effect of adrenaline occurs through the beta-adrenergic receptor.

Possible involvement of Ca2+-calmodulin system in cyclic AMP action in cholesterol ester hydrolytic response to ACTH in bovine adrenocortical cells

In order to elucidate the relationship between cyclic AMP and the Ca2+-calmodulin system in the steroidogenic response to adrenocorticotropic hormone (ACTH), the effects of calmodulin inhibitors (trifluoperazine and W-7) on cortisol production and cellular cholesterol ester hydrolysis induced by ACTH or dibutyryl cyclic AMP in bovine adrenocortical cells were examined in the absence of extracellular Ca2+. These calmodulin inhibitors inhibited not only the cortisol production and the cholesterol ester hydrolysis induced by ACTH in the absence of extracellular Ca2+, but also inhibited the dibutyryl cyclic AMP-induced cortisol production and the cholesterol ester hydrolysis in the absence of extracellular Ca2+. These results suggested the possibility that cyclic AMP action was mediated by the Ca2+-calmodulin system in the activation process of cellular cholesterol ester hydrolysis in the steroidogenic response to ACTH.

Influences of stable iodine upon the concentration of radioactive iodine by marine organisms

Uptake and loss of radioactive iodine by marine organisms were studied in the artificial seawater in which the concentration as well as chemical forms of both stable and radioactive iodine were controlled. The concentration factors of radioactive iodine by these organisms were clearly dependent upon the concentration of stable iodide ion in the culture media while the concentration of stable iodate ion did not affect the uptake and loss of radioactive iodine. It was observed that the higher the concentration of iodide ion was in the culture media the shorter the biological half-life of radioactive iodine became, and thus the lower the concentration factor resulted in.

Chemical forms of radioactive iodine in seawater and its effects upon marine organisms

Chemical forms of radioactive iodine and its effects upon marine organisms were studied by the tracer experiments. Seaweeds or fish were held in the aquarium in which the 125I tracer in either iodide or iodate form was inoculated. Iodide form of 125I was taken by Dorome (Chasmichthys gulosus) with the concentration factor of about 10 and excreted with the biological half-life of 15 days, while iodate form of 125I was not taken up appreciably and the concentration factor did not greatly exceed unity. Uptake and loss of 125I were studied as well for 3 species of seaweeds, Hijiki(Hizikia fusiforme), Nejimoku (Sargassum sagamianum) and Tsunomata (Chondrus ocellatus). Iodate form of 125I was accumulated less than iodide form by these seaweeds but the concentration factor of iodate by these seaweeds was very high compared to those by fish.

A possible role of "steroidogenic factor" in the corticoidogenic response to ACTH; effect of ACTH, cycloheximide and aminoglutethimide on the content of cholesterol in the outer and inner mitochondrial membrane of rat adrenal cortex

The role of a "steriodogenic factor" in the corticoidogenic response to adrenocorticotropic hormone (ACTH) was studied in this experiment. ACTH caused an accumulation of cholesterol within the adrenocortical mitochondria in rat after pretreatment with either cycloheximide (CH) or aminoglutethimide (AG). The cholesterol distribution in these cholesterol-rich mitochondria was examined by measuring the cholesterol concentrations in the outer and inner mitochondrial membranes. In the case of pretreatment with CH, cholesterol was accumulated in the outer membrane and not in the inner membrane. In contrast, in the case of pretreatment with AG, cholesterol was accumulated in the inner membrane and not in the outer membrane. It could be concluded from the presented data that the function of a "steroidogenic factor" in the corticoidogenic response to ACTH might take place at the step of cholesterol translocation from the outer mitochondrial membrane to the inner membrane.

Studies on adrenocorticotropic hormone receptor using isolated rat adrenocortical cells

To clarify the function of ACTH receptors, the actions of ACTH on cyclic AMP formation, Ca2+-influx across cell membrane, and corticoidogenesis were examined using dispersed adrenocortical cells prepared from the rat adrenal gland. 1) There are two types of ACTH receptors from Scatchard analysis of 125I-ACTH1-24 binding to the cell, the one receptor is of high affinity and low capacity (dissociation constant (Kd1) = 2.6 x 10(-19) M and 7,350 sites per cell), and the other one is of low affinity and high capacity (dissociation constant (Kd2) = 7.1 x 10(-9)M and 57,400 sites per cell). 2) Both apparent dissociation constants derived from the effects of ACTH on corticoidogenesis and Ca2+ influx well correspond with Kd1 of the high affinity receptor, 3) Apparent dissociation constant obtained from the effect of ACTH on cyclic AMP formation is in good agreement with Kd2 of the low affinity receptor. Thus it could be deduced from these data that the high affinity receptor is concerned with an increased Ca2+-influx to regulate corticoidogenesis at physiological levels of ACTH, whereas the low affinity receptor is coupled to adenylate cyclase at supraphysiological concentrations of ACTH.