Biomedical subjects

Masatoshi Morita

Publications and source records attributed to Masatoshi Morita.

At least 19 recordsLinked to original sources

PubMed2006

Anticonflict effects of lavender oil and identification of its active constituents.

The pharmacological effects of lavender oil were investigated using two conflict tests in ICR mice, and then the active constituents were identified. Lavender oil produced significant anticonflict effects at 800 and 1600 mg/kg in the Geller conflict test and at 800 mg/kg in the Vogel conflict test, suggesting that the oil has an anti-anxiety effect. Analysis using GC/MS revealed that lavender oil contains 26 constituents, among which alpha-pinene (ratio, 0.22%), camphene (0.06%), beta-myrcene (5.33%), p-cymene (0.3%), limonene (1.06%), cineol (0.51%), linalool (26.12%), borneol (1.21%), terpinene-4-ol (4.64%), linalyl acetate (26.32%), geranyl acetate (2.14%) and caryophyllene (7.55%) were identified. We examined the effects of linalool, linalyl acetate, borneol, camphene, cineol, terpinen-4-ol, alpha-pinene and beta-myrcene using the Geller and Vogel conflict tests in ICR mice. Cineol, terpinen-4-ol, alpha-pinene and beta-myrcene did not produce any significant anticonflict effects in the Geller test. Linalyl acetate did not produce any significant anticonflict effects in either test. Both borneol and camphene at 800 mg/kg produced significant anticonflict effects in the Geller, but not in the Vogel conflict test. Linalool, a major constituent of lavender oil, produced significant anticonflict effects at 600 and 400 mg/kg in the Geller and Vogel tests, respectively, findings that were similar to those of lavender oil. Thus, we concluded that linalool is the major pharmacologically active constituent involved in the anti-anxiety effect of lavender oil.

Animals↗

PubMed2006

Antiestrogenic activity of vitamin A in in vivo uterotrophic assay.

All-trans-retinoic acid (ATRA), the primary active metabolite of vitamin A, was examined for its antiestrogenic activity in rats using an in vivo uterotrophic assay. All rats were ovariectomized 2 weeks prior to receiving 5 mg/kg/day ATRA or 0.3 micro g/kg/day ethynyl estradiol (EE) subcutaneously once a day for 3 consecutive days. Rats were sacrificed 1, 3, 6, 12 or 24 h after the last treatment. EE increased uterine weight and the coinjection of ATRA with EE significantly suppressed this effect 3 and 24 h after treatment. mRNA expression was examined during this 24-h period and the mRNA expression levels of estrogen receptor alpha (ER alpha), retinoic acid receptor beta (RAR beta), retinoid X receptor gamma (RXR gamma) and cellular retinol-binding protein I (CRBP I) were found to have significantly increased in the ATRA+EE group compared with those in the EE group. This is the first report on the antiestrogenic activity of ATRA determined using an in vivo adult rat uterotrophic assay. The up-regulation of RAR or RXR mRNA expression level was probably responsible for the antiestrogenic activity of ATRA.

Animals↗

PubMed2006

Feminization of Japanese medaka (Oryzias latipes) exposed to 17beta-estradiol: effect of exposure period on spawning performance in sex-transformed females.

Two groups of Japanese medaka (Oryzias latipes) were exposed to 17beta-estradiol (E2: 150ng/L, nominal concentration) for either a short-term exposure (STE: 0-31 days after fertilization (daf); egg-larval period) or a long-term exposure period (LTE: 0-81 daf; egg-adult period) and their subsequent spawning performance was compared in terms of fecundity, spawning time, and fertility. Most genetic males were transformed to phenotypic females by E2 following both short-term and long-term exposure, but spawning performance and gonad somatic index (GSI) of sex-transformed females (XY females) following long-term exposure were lower than those of sex-transformed females following short-term exposure and those of normal females (XX) in the control group. Sex-transformed females in the STE group and normal females possessed mature ovary, whereas most of the sex-transformed females in the LTE group possessed immature ovary, with most oocytes being in the pre-vitellogenic phase. Moreover, the chromosome types of first filial generation delivered from sex-transformed female in STE group composed with 51.9% as XY, 18.5% as YY, and 29.6% as XX. From these results, it seems that exposure to E2 until the end of the larval period produces sex-transformed medaka with high reproductive ability, similar to normal females, but longer exposure to E2 may inhibit sexual maturation in the sex-transformed female.

Animals↗

PubMed2006

Very high concentrations of DDE and toxaphene residues in crocodiles from the Ord River, Western Australia: an investigation into possible endocrine disruption.

Organochlorine pesticide concentrations, particularly those of the DDT family and of toxaphene, were measured by gas chromatography in samples of liver and body fat taken from Australian freshwater crocodiles Crocodylus johnstoni at three locations along the Ord River in Western Australia. The three sampling sites were the irrigation area, downstream of the irrigation area, and well upstream of the irrigation area; the last site serving as the control. DDT and toxaphene were applied in large and known quantities to cotton grown in the Ord Irrigation Area from 1964 to 1974. Thus the residues in the crocodile tissues are representative of the situation almost thirty years after the use of DDT and toxaphene ceased in the area. Very high concentrations of p,p'-DDE and toxaphene were found in the lipid-rich tissues that were examined. Livers and body fat from estuarine crocodiles Crocodylus porosus from the downstream site were also analysed. As p,p'-DDE and toxaphene are both known to be disruptive of endocrine systems, a range of blood parameters, including estradiol and testesterone concentrations, were also measured for all the animals studied. The ovaries and testes of the freshwater crocodiles were also examined histologically. There were no obvious effects on blood chemistry or gonad histology of the large burden of pesticides and their metabolites carried by exposed animals, although the limited number of samples and the variability of the breeding state of the animals examined may have masked possible effects. The isolation of the area, the accurately known applications of DDT and toxaphene, and the simplicity of the drainage system make the lower Ord River a unique natural laboratory for studying the long term breakdown and effects of pesticides applied in a tropical environment.

Alligators and Crocodiles↗

PubMed2006

Horizontal distribution of steroid estrogens in surface sediments in Tokyo Bay.

A monitoring survey was conducted to investigate the distribution of steroid estrogens and their conjugates in surface sediments of Tokyo Bay for the first time, which is known as one of the most heavily polluted marine embayments in the world. The surface sediment samples were collected at 20 locations covering the whole area of Tokyo Bay and analyzed for steroid estrogens and their conjugates using liquid chromatography-tandem mass spectrometry. The concentrations of 17beta-estradiol (beta-E2) and estrone (E1) ranged from ND (below the detection limit; <0.07) to 0.59 and from 0.05 to 3.60 ng g-1 dry, respectively. Those concentrations were higher in the northern part of the bay, which is directly receiving huge quantities of pollutants from adjacent rivers containing a large amount of municipal and industrial wastewater. 17alpha-Estradiol (alpha-E2) and estrone-3-sulfate (E1-3S) were detected in some of the samples, whereas neither of the other conjugates, estriol (E3) or 17alpha-ethynylestradiol (EE2), was found.

Chromatography, Liquid↗

PubMed2006

Diastereoisomerism of thiol complexes of arsenic acids and pseudoasymmetry of arsenic: a 1H and 13C NMR study.

Diastereoisomeric complexes of methylphenylarsinic acid and (L)-glutathione could be partially separated by HPLC, but the separated compounds rapidly racemized, presumably by pyramidal inversion at the arsenic atom. Hydrolysis of the diastereoisomeric complexes yielded methylphenylarsinous acid as a pair of enantiomers revealed by a 1H NMR study with an asymmetric lanthanide shift reagent. Methylphenylarsinous acid was also synthesized as an enantiomeric pair, shown by an asymmetric shift reagent experiment, by the hydrolysis of iodomethylphenylarsine. 1H and 13C NMR spectroscopy were used to demonstrate that complexing of phenylarsonic acid with (R,S)-3-mercapto-1,2-propanediol and with (R,S)-1-mercapto-2-propanol yielded, in each case, a pair of enantiomers, PhAs[(R)-ligand)]2, PhAs[(S)-ligand)]2, in which the homomorphic ligands were diastereotopic, and a pair of diastereoisomers, PhAs[(R)-ligand][(S)-ligand], which differed from each other in the configuration about the pseudoasymmetric arsenic atom.

Arsenates↗

PubMed2006

In ovo exposure quail assay for risk assessment of endocrine disrupting chemicals.

Although there are in vivo assays using various organisms for the risk assessment of chemicals with endocrine disrupting properties, effective experimental methods for avian species are still under debate. We have developed an in ovo exposure assay using Japanese quail eggs, aimed at assessing disrupting effects on avian reproductive development and function. Hybrid eggs from Brazilian Brown male and White Egg female quails, which can be genetically sexed by their plumage color after hatching, were prepared, and test materials dissolved in olive oil were injected into the air-chamber on day 10 of incubation. After sexual maturation of hatched chicks, we observed egg production by females and the egg quality and male-typical reproductive behavior, and then examined reproductive system morphology and serum steroid concentrations in both sexes. Treatment with a synthetic estrogen, diethylstilbestrol (DES, 0.5-50 ng/g egg), dose-dependently reduced the eggshell thickness and strength of eggs. A few females treated with 5 ng/g DES per egg produced soft-shelled/ unmarked eggs, and all laying females treated with 50 ng/g egg produced eggs completely lacking shells. DES also induced shortening of the left oviduct and abnormal development of the right oviduct in a dose-dependent manner, while testis weight was reduced symmetrically. In addition, 2,2',4',6'-tetrachlorobiphenyl-4-ol (10-1,000 ng/g egg), which previously showed relatively high estrogenic activity in vitro, caused dose-dependent shortening of the left oviduct and reduction in testis weight. The methods for evaluating endocrine disrupting effects and preparing experimental birds proposed in the present study are expected to facilitate assays for avian reproductive toxicology.

Animals↗

PubMed2006

Effects of dioxins on the quantitative levels of immune components in infants.

Dioxins (polychlorinated dibenzo-p-dioxin (PCDD)+polychlorinated dibenzofuran (PCDF)) and polychlorinated biphenyls (PCBs) are potentially hazardous compounds and have structural similarity with thyroid hormones. Animal studies have demonstrated that PCDDs, PCDFs and PCBs can alter immune functions. However, in humans it is not yet elucidated whether dioxins contained in breast milk have any effects on the immune functions in infants. To investigate the effects of dioxins on the immune system, we compared the quantitative levels of immune components between a breast-fed group and bottle-fed group, in which dioxin concentration is almost zero. Ratios of immune cells, such as CD4+ and CD8+ T-lymphocytes, as well as B-lymphocytes (CD19+ and/or CD20+) and NK cells (CD16+, CD56+) in peripheral blood lymphocytes, serum immunoglobulin level, and level of specific IgE antibody to allergens in the venous blood at 12 months of age were assessed in a subgroup of 281 infants. The relationship of post-natal dioxin exposure via breast feeding with the ratio of immunological markers and the level of humoral antibodies up to 12 month of age was not demonstrated. In conclusion, it would appear that the content of dioxins in breast milk in the Japanese general population is not enough to induce any change in theses-examined immunological parameters during the first year of life, although long-term effects remain to be evaluated.

Adult↗

PubMed2006

Impact of tributyltin and triphenyltin on ivory shell (Babylonia japonica) populations.

We histopathologically examined gonads and chemically determined organotin compounds in tissues of the ivory shell, Babylonia japonica. Imposex (a superimposition of male-type genital organs on females) occurred in approximately 80-90% of B. japonica specimens that we examined, with the penis and vas deferens both well developed. No oviduct blockage by vas deferens formation was observed. Ovarian spermatogenesis and suppressed ovarian maturation were observed in the females that exhibited imposex, although no histopathological abnormalities were found in males. Tissue distributions of organotin compounds [tributyltin (TBT), triphenyltin (TPhT), and their metabolites] were different for butyltins and phenyltins; a remarkably high accumulation of TBT was observed in the ctenidium, osphradium, and heart, whereas high concentrations of TPhT were detected in the ovary and digestive gland. More than one-third of TBT accumulated in the digestive glands of both males and females, followed by the testis, ctenidium, muscle, and heart tissues in males and in the muscle, ovary, ctenidium, and head tissues (including the central nervous system ganglia) in females. In both males and females, more than half of total TPhT accumulated in the digestive glands, followed by the gonads. The next highest values were in the muscle, ctenidium, and heart tissues in males and in the muscle, oviduct, and head tissues in females. Both TBT and TPhT concentrations in the gonads were positively correlated with penis length in females. Our findings strongly suggest that reproductive failure in adult females accompanied by imposex, possibly induced by TBT and TPhT from antifouling paints, may have caused the marked decline of B. japonica populations in Japan.

Animals↗

PubMed2005

Feminization of Japanese medaka (Oryzias latipes) exposed to 17beta-estradiol: formation of testis-ova and sex-transformation during early-ontogeny.

Gonad histological changes were examined in Japanese medaka exposed to 17beta-estradiol (E2) during early-life stages. Two experiments were conducted at different concentrations of E2 (33.5 and 140.6 ng/L, mean value of measurement) and larvae and juveniles were observed for histological changes in the gonad. Differentiation of ovary and testis in control fish was apparent 12 days post-hatch (dph). At 12 dph, normal testes were observed in male fish that had been exposed to 33.5 ng/L E2, but at 14 and 20 dph, testis-ova was recognized in male fish. Male fish exposed to 140.6 ng/L E2 had testis-ova at 12 dph and gradual transformation to ovary was observed in male fish until 20 dph. In both experiments, the ovarian tissue in testis of male fish exposed to E2 was frequently distributed along the central transverse axis of the gonad, expanding into the transverse axis. The results indicated that 17beta-estradiol can induce testis-ova in male medaka during the larval period and sex-transformation is more frequent at higher (140.6 ng/L) than lower concentrations (33.5 ng/L) of estradiol. The results also demonstrated that testis-ova first appear in the central area of the transverse axis of testis.

Animals↗

PubMed2005

Genetic differences in the production of male neonates in Daphnia magna exposed to juvenile hormone analogs.

We studied the susceptibility of three genetically different strains of the cyclical parthenogen Daphnia magna (Cladocera, Crustacea) in producing male neonates following exposure to juvenile hormone analogs. In experiment 1, NIES, Clone A, and Belgium A strains were exposed to the insect growth regulators (IGRs) fenoxycarb or epofenonane in a 21-day reproduction experiment. Fenoxycarb exposure decreased the total number of neonates and increased production of male neonates in a concentration-dependent manner in the NIES strain. The decrease in the total number of neonates was so great in Clone A following fenoxycarb exposure that male neonates were not observed, even at the highest concentration, where the total number of neonates was only 2% of the control. In the Belgium A strain, male neonates were observed at a rate of about 20% following exposure to the highest fenoxycarb concentration, but the total number observed was small. Epofenonane did not decrease reproduction in the NIES and Belgium A strains as dramatically as did fenoxycarb, but the neonatal sex ratio changed in a concentration-dependent manner. Although the ratio of males was as low as about 10%, induction of male neonates was also observed in Clone A following epofenonane exposure. In experiment 2, gravid females were exposed to high concentrations (5 or 10 microg/l) of fenoxycarb or pyriproxyfen for 12h. These treatments induced the production of male neonates in all strains, with a small decrease in the total number of neonates. Although induction of male neonates by juvenile hormones and their analogs was universal among genetically different strains, care is needed in interpreting the results of the 21-day reproduction tests, because decreased numbers of neonates at higher concentrations could obscure the presence of male neonates.

Animals↗

PubMed2005

Aerial oxidation of the glucocorticoid side-chain under pH control.

The outcome of aerial oxidation of the glucocortico-steroid side-chain (as exemplified by dexamethasone) has been shown to be subject to strict pH control. At pH 7.4 the glyoxal is the only product; at pH values of 8 and 9.2 the etioacid is formed, and at pH values of 13 or above the epimeric glycolic acids are produced. The glycolic acid epimer that predominates by a factor of 2 and is more stable has been shown by an X-ray crystal structural analysis to be the 20R compound. The presence of arsenite changes the course of the reaction and only the glycolic acids are yielded at pH values of 8 and above.

Arsenites↗

PubMed2005

Continuing observation of disturbed reproductive cycle and ovarian spermatogenesis in the giant abalone, Haliotis madaka from an organotin-contaminated site of Japan.

Histological examination of gonads as well as chemical analysis of organotin compounds in tissues of the giant abalone, Haliotis madaka, was conducted to evaluate continuing endocrine disruption in abalone populations in Japan. Abalone specimens were collected from two different areas, Tsushima as a reference site and Jogashima as a site representative of declining abalone populations where serious organotin contamination had been observed, each month from January 1998 to March 1999. Scores were given to the development stages of reproductive cells in the ovary and testis. The degree of sexual maturation was evaluated by calculating the mean value of a histogram of these scores for the reproductive cells of each abalone. The temporal variations in degree of sexual maturation showed that female and male abalone from Tsushima matured synchronously, while those from Jogashima did not, which were similar to results of the previous study during September 1995-November 1996. Approximately 19% of the female abalone from Jogashima were masculinized with an ovo-testis, which was also similar to the result of the previous study. The masculinization of female abalone is reported to be induced by tributyltin (TBT) and triphenyltin (TPhT) from antifouling paints. Concentrations of the sum of butyltins (TBT, dibutyltin (DBT) and monobutyltin (MBT): SigmaBTs) and the sum of phenyltins (TPhT, diphenyltin (DPhT) and monophenyltin (MPhT): SigmaPhTs) in the muscle of abalone from Jogashima (n = 73) of 7.8+/-9.0 ng/g wet wt. and 4.5+/-6.8 ng/g wet wt., respectively, were significantly higher than those from Tsushima (n = 87) of 4.7+/-4.9 ng/g wet wt. and 0.8+/-1.7 ng/g wet wt., respectively (p < 0.05 for SigmaBTs; p < 0.001 for SigmaPhTs), although concentrations of TBT and TPhT in the muscle of abalone from Jogashima (n = 73) of 2.2+/-2.5 ng/g wet wt. and 5.8+/-5.1 ng/g wet wt., respectively, were insignificantly and significantly higher than those from Tsushima (n = 87) of 0.4+/-0.6 ng/g wet wt. and 0.5+/-0.9 ng/g wet wt., respectively, (p > 0.05 for TBT; p < 0.001 for TPhT). Thus, endocrine disruption as well as contamination by organotins in the giant abalone from Jogashima is still persisting.

Analysis of Variance↗

PubMed2005

Degradation of dioxins by cyclic ether degrading fungus, Cordyceps sinensis.

Use of the cyclic ether degrading fungus, Cordyceps sinensis strain A to degrade dibenzo-p-dioxin (DD), 2,3,7-trichlorodibenzo-p-dioxin (2,3,7-triCDD) and octachlorodibenzo-p-dioxin (octaCDD) has revealed a new degradation pathway for dioxins. Catechols and other possible degradation products were synthesized to facilitate the identification, detection and quantification of these products, and phenylboronate was used for the derivatization and analysis of dihydroxylated degradation products. Degradation of DD yielded catechol, which was further metabolized to cis,cis-muconate. 2,3,7-triCDD yielded mono- and dichloro-catechol as well as catechol itself; and the cis,cis-muconates were also detected. octaCDD gave mono- to trichloro-catechol as well as catechol, and the cis,cis-muconates were also found. For all tested dioxin samples dechlorination resulted in replacement of chlorine with hydrogen, and no hydroxylation was observed. It appeared that dechlorination may occur in the degradation of octaCDD to catechols and possibly in the subsequent degradation of chlorinated catechols and/or chlorinated cis,cis-muconates to further breakdown products.

Catechols↗

PubMed2005

RNA constitution and estrogen-responsive gene expression in the ovariectomized rat uterus.

Because reproductive tracts in ovariectomized rodents, which are commonly used in endocrinological studies, exhibit drastic changes in response to exogenous estrogens, quantitative evaluation of gene expression requires extra caution. We found that the whole mRNA content of total RNA in the uterus of the ovariectomized rat was dose-dependently reduced by treatment with 17alpha-ethynylestradiol (EE) for 3 consecutive days. Because of the decline in the ratio of mRNA/total RNA, real-time reverse transcriptase-polymerase chain reaction analysis seemingly showed that the relative ratios of the levels of stable RNAs, rRNA18S, rRNA5S, and tRNA-Gly, to whole mRNA were increased by EE. These results indicate that applying a fixed concentration of total RNA and stable RNA as an internal control to uterine mRNA quantification should be reconsidered. On the other hand, the beta-actin gene showed the most stable expression among the housekeeping genes examined. Using beta-actin mRNA as an internal control, we observed that tissue inhibitor of metalloproteinase-3 (TIMP3) mRNA was dose-dependently reduced 24 h after treatment with EE or bisphenol A for 3 days. Continued investigation of TIMP3 with an appropriate internal control may be helpful in elucidating the mechanisms involved in uterine activation.

Animals↗

PubMed2005

Estrogenic activity of impurities in industrial grade bisphenol A.

The estrogenicities of 10 compounds found as impurities in industrial grade bisphenol A (BPA) were measured by yeasttwo-hybrid assays incorporating the human estrogen receptor alpha(hERalpha) orthe medaka fish (Oryziaslatipes) estrogen receptor alpha (medERalpha). Five impurities showed greater activity than BPA itself in an agonist assay for hERalpha. p-Cumylphenol, the most active of the impurities in the hERalpha assay, was 12 times as active as BPA. The REC10 (10% relative effective concentration: 10% of the activity of 10(-8)M 17,B-estradiol) was 710 nM. Five impurities showed greater activity than BPA in an agonist assay for medERa: 4,4'-(1,3-dimethylbutylidene) bisphenol and 2-(4'-hydroxy-phenyl)-2,4,4-trimethylchroman were nearly equipotent and 9 times as active as BPA, and the REC10 values of these compounds in the medERalpha assay were 280 and 320 nM, respectively. Comparison of the experimentally determined estrogenicities of mixtures of BPA and 4,4'-(1,3-dimeth-ylbutylidene) bisphenol and those calculated by the concentrations addition (CA) method confirmed the suitability of the method for the prediction of the estrogenicities of the mixtures of BPA and its phenolic analogues. The measured estrogenicities of four samples of industrial grade BPA and laboratory grade (pure) BPA were not significantly different in either the hERalpha assay or the medERalpha assay (p > 0.05 in each case). We conclude that the impurities in industrial grade BPA, although some are of much higher estrogenic activity than BPA itself, do not significantly increase the estrogenicity of the industrial compound and therefore do not increase possible adverse health effects from such activity.

Animals↗

PubMed2005

Novel surface modified molecularly imprinted polymer focused on the removal of interference in environmental water samples for chromatographic determination.

Uniformly sized molecularly imprinted polymers (MIPs) for bisphenol A (BPA) with surface modification and immobilized intervals of functional monomers afforded by utilizing 4,4'-methylenebisphenol as a pseudo component have been prepared. MIPs for BPA were prepared using 4-vinyl pyridine immobilized in the most effective interval and ethylene glycol dimethacrylate as a functional monomer and cross-linking agent, respectively. Prepared MIPs showed significant selectivity for BPA retention and removal performance for interference in actual samples as the HPLC stationary phase compared to those of ordinary MIPs. These MIPs were employed as pretreatment media of column switching HPLC and the HPLC system provided a detection limit of 0.36 ppt when electrochemical detection was used. Actual samples, including Suwannee River natural organic matter (NOM), were applied and BPA was detected in the NOM even if widely used UV detection was employed.

Chromatography, High Pressure Liquid↗

PubMed2005

Production of male neonates in Daphnia magna (Cladocera, Crustacea) exposed to juvenile hormones and their analogs.

We exposed the water flea Daphnia magna (Cladocera, Crustacea) to either juvenile hormone I (JH I), juvenile hormone II (JH II), or the juvenile hormone-mimicking insecticides kinoprene, hydroprene, epofenonane, or fenoxycarb. By 21-day reproduction tests, we investigated the effects on the number of neonates born per female and the offspring sex ratio. All six chemicals induced D. magna to produce male neonates; the male sex ratio of the offspring increased as the chemical concentration increased. EC50 values for production of male neonates were estimated as 400 (JH I), 410 (JH II), 190 (kinoprene), 2.9 (hydroprene), 64 (epofenonane), and 0.92 (fenoxycarb) microg/l. The number of neonates produced was reduced with all chemicals at the concentrations investigated. At the EC50 for male production, five of the six chemicals reduced the reproductive rate to less than 50%; the exception was epofenonane, which caused only a slight reduction in reproductive rate. These results were similar to those obtained for five juvenoids studied previously, one of which was studied here again. There are now 10 chemical substances--all juvenile hormones or their analogs-that are known to induce D. magna to produce male neonates. This suggests that juvenile hormone is involved in initiating male production followed by sexual reproduction in D. magna, and probably in most cladocerans that exhibit cyclic parthenogenesis.

Animals↗