Effect of oral administration of clinically relevant doses of dexamethasone on regulation of cytochrome P450 subfamilies in hepatic microsomes from dogs and rats

OBJECTIVE: To evaluate the effect of oral administration of dexamethasone (DEX) at clinically relevant doses on metabolic activities of cytochrome P450 (CYP) isoenzymes in dogs and rats. ANIMALS: 15 healthy 1-year-old male Beagles and 20 healthy 10-week-old male Wistar rats. PROCEDURE: Hepatic microsomes were harvested from dogs treated orally with DEX at 2.5 and 7.5 mg for 5 days and from rats treated orally with DEX at 0.75, 6, and 48 mg/kg for 5 days. 7-ethoxyresorufin, tolbutamide, bufuralol, and midazolam were used as CYP1A, CYP2C, CYP2D, and CYP3A substrates, respectively. Concentrations of metabolites formed by CYPs were measured by use of high-performance liquid chromatography, except for the resorufin concentrations measured by use of a fluorometric method. Reaction velocity-substrate concentration data were analyzed to obtain maximum reaction velocity (Vmax) and Michaelis-Menten constant (Km). RESULTS: Values of Vmax for midazolam 4-hydroxylation were significantly decreased by treatment with DEX at 2.5 and 7.5 mg in dogs, although values of Km were not affected. Values of Vmax for bufuralol 1'-hydroxylation were also decreased by treatment with DEX. In rats, values of Vmax for midazolam 4- hydroxylation were significantly decreased by treatment with DEX at 0.75 and 6 mg/kg but significantly increased at 48 mg/kg. Other reactions were not affected by treatment with DEX. CONCLUSIONS AND CLINICAL RELEVANCE: Our results indicate that DEX downregulates the CYP3A subfamily when administered at clinically relevant doses to dogs. The effect of downregulation of CYP3A in dogs treated with DEX should be considered to avoid adverse effects from coadministration of drugs.     

金缕梅的叶芽形成与花芽分化

金缕梅的腋芽（叶芽）由前出叶和叶原基构成，顶芽由叶原基构成。其叶原基被两枚布满绒毛的托叶紧密包住。叶芽的叶原基分化期为５～１１月，６～８月高温季节曾一度停止分化，最后只分化出４枚叶原基。花芽（腋芽）由前一年分化的１枚前出叶、２枚退化叶和翌年４月开始分化的１枚总苞叶、３枚苞叶和３朵小花构成；小花由２枚小苞、４枚萼片、４枚花瓣、８条雄蕊和２心室雌蕊构成。花芽发育主要在４～９月，于６月形成雌蕊以成后发育     

Evaluation of calcium-alginate gel as an artificial diet medium for bioassays on common cutworms

A calcium-alginate gel diet was developed for Spodoptera litura larvae, and its reliability as a carrier for incorporating antifeedants as well as insecticides was investigated. The alginate gel diet was prepared with a simple protocol, which does not involve any heating process. When tested using this diet, acephate, a Bacillus thuringiensis endotoxin formulation and rotenone reproducibly showed insecticidal activity against the larvae, while neem oil and scabequinone deterred the larval feeding effectively. However, not only the insecticidal activity of acephate but also the antifeedant activity of neem oil was reduced by replacing the alginate component by agar in the diet, suggesting the usefulness of the alginate gel diet as an assay tool for testing a broad range of samples against the larvae.     

Copper and zinc balance in soils,rice plants and aquatic systems in an area along the fuchu precipice line,Tokyo, Japan

The abundance and distribution of Cu and Zn in spring water, irrigation water and sediment from the Fuchu Irrigation Canals, ground water for irrigation, rice plants and paddy soil at Tokyo University of Agriculture and Technology's Hommachi Farm were studied. The balance of Cu and Zn in the paddy field at the Hommachi Farm was investigated. The discharge of Cu and Zn influenced by human activities was observed in sediment of the Fuchu Irrigation Canal, and rice plants and paddy soil at the Hommachi Farm where irrigation water from the Fuchu Irrigation Canal was used until 1970. From Cu and Zn balance calculated, several hundred years are needed to decrease by half the present level of these metals at the Hommachi Farm.     

Heavy metal accumulations in a semi-enclosed hypereutrophic system: Lake Teganuma,Japan

Heavy metal concentrations and other physical and chemical properties were studied so as to assess the heavy metal accumulation process in the sediments of a hypereutrophic lake, Lake Teganuma, Japan. The accumulations were most evident near the inflow inlets of two main inflow rivers in Kaminuma (the west part of Lake Teganuma) with the significant Zn accumulation. Except for Fe, the vertical distributions of heavy metals showed the highest concentrations in the surface 10 cm and decreased gradually with the sediment depth. The high concentrations in the upper layer was caused by an increase in the non-residual fractions. The large influx of heavy metal to Lake Teganuma seems to be due to the domestic effluents via the two rivers in last decades.     

Effects of low temperature and shade on relationships between nodulation,vesicular-arbuscular mycorrhizal infection,and shoot growth of soybeans

The effects of low temperature and reduced light on a Glycine-Bradyrhizobium-Glomus spp. symbiosis were examined in pot experiments. Soybean plants, Glycine max L. Merr. cv. Tachiyutaka, were grown with N fertilization or inoculation with Bradyrhizobium japonicum plus P fertilization or inoculation with Glomus mosseae in the glasshouse. After the flowering stage, half the pots with soybean plants were subjected to low temperature (15°C 14h/13°C 10 h) with light reduced by shading. At 0, 7, 16, and 28 days after the application of the treatments, the growth, nodulation, vesicular-arbuscular mycorrhizal (VAM) infection and the N and P contents of the soybean plants were measured. In all symbiont-fertilization combinations, the low-temperature treatment reduced the production of dry matter by the soybeans. Nodulation (weight and number) was slightly reduced by this treatment but the proportion of larger nodules was increased. The root length infected by the VAM fungus was little affected by the low-temperature treatment. Both the nodule weight and the infected root length were linearly related to shoot dry weight regardless of treatment and of the symbiont-fertilization combination used. These results suggest that the growth of the symbionts on the root was in balance with the shoot growth of the host, irrespective of climatic conditions, and imply a considerable degree of host control. P inflows to root systems were greatly affected by low-temperature treatment regardless of the symbiont-fertilization combination. This suggests that a simple comparison of P inflows between mycorrhizal and non-mycorrhizal plants may give misleading information on the effects of low temperature or reduced light conditions on P uptake by mycorrhizal plants.     

Developmental ability of somatic cell nuclear transferred embryos aggregated at the 8-cell stage or 16- to 32-cell stage in cattle

Aggregation of somatic cell nuclear transfer (SCNT) embryos in mice is reported to improve full-term development. In the present study, we attempted to improve the development of SCNT embryos by aggregation in cattle. In Experiment 1, to examine the effect of the timing of aggregation on in vitro development of cumulus-cell NT embryos, we aggregated two or three SCNT embryos (2X or 3X embryos) at the 1-cell, 8-cell and 16- to 32-cell stages. Irrespective of the timing of aggregation, 3X embryos developed to the blastocyst stage at a high rate. However, aggregation did not improve the total blastocyst formation rate of the embryos used. The cell numbers of 3X embryos aggregated at the 1-cell stage and 2X embryos tended to be higher than that of single NT embryos (1X embryos). Furthermore, a significant increase in cell number was observed in 3X embryos aggregated at the 8-cell stage and 16- to 32-cell stage. In Experiment 2, we used fibroblast cells as nuclear donors and examined in vitro development of 3X embryos aggregated at the 8-cell stage and 16- to 32-cell stage. As a result, 3X embryos had high blastocyst formation rates and higher cell numbers than 1X embryos, which was consistent with the results of Experiment 1. In Experiment 3, we examined the full-term developmental ability of 3X embryos aggregated at the 8-cell stage and 16- to 32-cell stage. After transfer of fibroblast-derived NT embryos into recipient animals, a significantly higher pregnancy rate was obtained on Day 60 in 3X embryos than in 1X embryos. Two embryos aggregated at 8-cell stage and one embryo aggregated at the 16- to 32-cell stage developed to term, while no pregnancies derived from 1X embryos that lasted to Day 60. However, two of the cloned calves were stillborn. These results suggest that aggregation of the 8-cell stage or 16- to 32-cell stage SCNT embryos may improve the pregnancy rate, but that it cannot reduce the high incidence of fetal loss and stillbirth, which is often observed in bovine SCNT.     

Molecular cloning, tissue expression, and subcellular localization of porcine peptidoglycan recognition proteins 3 and 4

Peptidoglycan recognition proteins (PGRPs) are innate immune molecules that are present in most invertebrates and vertebrates. Mammals have four PGRPs, PGLYRP1-4. In the present study, we cloned the cDNAs encoding porcine PGLYRP3 and 4 from the esophagus of adult swine. The length of the complete open reading frames of porcine PGLYRP3 and 4 are identical and contain 1125bp encoding 374 amino acid residues. The amino acid sequences of these two proteins were more similar to their human orthologs (78.9% [PGLYRP3] and 73.9% [PGLYRP4]) than to their mouse orthologs (71.3% [PGLYRP3] and 67.9% [PGLYRP4]). Expression analysis revealed that both PGLYRP3 and 4 were more strongly expressed in digestive tract, especially the esophagus, than in immune organs such as spleen or mesenteric lymph nodes in both newborn and adult swine. To analyze the subcellular distribution of porcine PGLYRP1-4, we constructed transfectant cell lines. Western blot and flow cytometric analyses revealed that porcine PGLYRP3 and 4 are not only secreted, but also expressed on the cell surface, unlike PGLYRP1 and 2. These results should help contribute to the understanding of PGLYRP3- and 4-mediated immune responses via their recognition of intestinal microorganisms in newborn and adult swine.     

Chloritization in lowland paddy soils

This paper is concerned with the alteration of clay minerals which takes place when well-aerated lowland soils (Brown lowland soils) are cultivated for growing rice. For this purpose the clay mineral compositions of paddy soils were compared with those of adjacent arable soils at four locations.

In the case of arable soils a larger part of the 14Å spacings collapsed to 10Å on treatment with NH₄NO₃ solution, or on drying at about 100°C, whereas in paddy soils the spacings were more stable to thelie treatments. Cation exchange capacities of clays were always smaller In paddy soils than in arable soils. Alternate treatments of reduction and oxidation somewhat increased the stability of the 14Å spacings to heat treatment.

These results indicate that chloritization is a very common process occurring in lowland paddy sons. Chloritization In paddy soils appears to be closely associated with the seasonal cycle of reduction and oxidation.     

Proton consumption with phosphate adsorption on amorphous fe(iii) hydroxide

Proton consumption with phosphate adsorption on amorphous Fe (III) hydroxide (am-Fe(OH)₃) was compared between two different pH-controlled conditions in a 0.1 mol dm^-3 NaClO₄ solution at initial pH values of 5.50 and 4.50, at 298±0.005 K.

The number of protons caused by phosphate dissociation was subtracted from the total number of protons consumed, then the amount of surface OH groups released by the ligand exchange reaction were determined. When a sequential acid titration by a pH-stat maintained pH values of the systems at initial pH values, the percentage of OH groups released during the ligand exchange reaction was almost constant, 29–37%. When the pH values of the systems increased with phosphate adsorption, the percentage of OH groups released by the ligand exchange reaction varied from -4.3 to 33%. The difference in the proton migration between the two pH-controlled conditions not only depended on the phosphate dissociation, but on the difference in the adsorption mechanism, i.e. the ratio of ligand exchange with OH groups to total phosphate adsorption.