Biomedical subjects

N Yamashita

Publications and source records attributed to N Yamashita.

At least 19 recordsLinked to original sources

PubMed2006

Perfluorooctanesulfonate and related fluorochemicals in human blood samples from China.

Perfluorooctanesulfonylfluoride (POSF)-based compounds have been manufactured and used in a variety of industrial applications. These compounds degrade to perfluorooctanesulfonate (PFOS) which is regarded as a persistent end-stage metabolite and is found to accumulate in tissues of humans and wildlife. PFOS, perfluorohexanesulfonate (PFHxS), perfluorooctanoate (PFOA), and perfluorooctanesulfonamide (PFOSA) have been found in human sera from the United States. In this study, concentrations of PFHxS, perfluorobutanesulfonate (PFBS), PFOS, perfluorohexanoic acid (PFHxA), PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and PFOSA were measured in 85 samples of whole human blood collected from nine cities (eight provinces) in China, including Shenyang (Liaoning), Beijing (Hebei), Zhengzhou (Henan), Jintan (Jiangsu), Wuhan (Hubei), Zhoushan (Zhejiang), Guiyang (Guizhou), Xiamen (Fujian), and Fuzhou (Fujian). Among the 10 perfluorinated compounds (PFCs) measured, PFOS was the predominant compound. The mean concentration of PFOS was greatest in samples collected from Shenyang (79.2 ng/mL) and least in samples from Jintan (3.72 ng/mL). PFHxS was the next most abundant perfluorochemical in the samples. No age-related differences in the concentrations of PFOA, PFOS, PFOSA, and PFHxS were observed. Gender-related differences were found,with males higher for PFOS and PFHxS, and females higher in PFUnDA. Concentrations of PFHxS were positively correlated with those of PFOS, while concentrations of PFNA, PFDA, and PFUnDA were positively correlated with those of PFOA. There were differences in the concentration profiles (percentage composition) of various PFCs in the samples among the nine cities.

Adolescent↗

PubMed2006

Chloronaphthalenes composition of several batches of Halowax 1051.

Halowax 1051 is the highest chlorinated technical chloronaphthalene mixture among seven known formulations of the Halowax series. Octa- and heptaCN homologue groups are the main CN constituents of Halowax 1051 with declared 90% and 10% contents, respectively. In this study, using an isotope dilution technique and HRGC/HRMS, octaCN and heptaCNs contents of six batches of Halowax 1051 were between 82-93% and 6.2-17%, respectively. Also mono- to hexaCNs were found in Halowax 1051, and their content more or less varied according to the batch; also, the abundance of a particular CN congeners varied. Tetra-, penta- and hexaCNs have been found in all six batches of Halowax 1051 examined, and their contents varied between 0.0024-0.77%, 0.031-0.22%, and 0.21-0.82%, respectively. TriCNs have been found in three of six batches, and mono- and diCNs in two of six batches with 0.0020-0.40, 0.0017-0.25 and 0.0012-0.34% for positive findings, respectively. 2,3-DiCN (no. 10), 1,8-diCN (no. 9) at < 0.0002 mg/g, 1,6,7-/2,3,6-triCNs (nos. 25/26), 1,3,8-triCN (no. 22) at < 0.0002 mg/g, 1,3,6,7-tetra (no. 44), 1,2,3,6-tetra- (no. 29), 1,2,7,8-tetraCN (no. 41) and 1,2,3,6,7,9-hexaCN (no. 70) at < 0.0005 mg/g have not been found in Halowax 1051.

Dioxins↗

PubMed2006

HRGC/HRMS analysis of chloronaphthalenes in several batches of Halowax 1000, 1001, 1013, 1014 and 1099.

Chloronaphthalene (CN) congeners and homologue groups have been quantified in up to three batches of several types of technical CN formulations of the Halowax series (Halowax 1031, 1000, 1001, 1013, 1014 and 1099), to elucidate possible batch-to-batch compositional variations. Using isotope dilution and HRGC/HRMS a relatively large variation in CN congeners and homologues composition among the batches of particular types of the Halowax formulations could be noted, and also when compared to the composition declared by the manufacturer. Depending on the type of the Halowax formulation and its batch in total up to 54 peaks from chloronaphthalenes (Agilent Ultra 2 liquid phase), which represented 70 of 75 CN congeners theoretically possible, could be found in these mixtures. These congeners represented all CN homologue groups from mono- to octaCN but some co-eluted. A co-eluting congeners were such as: 1,4-/1,6- (nos. 5/7), 1,5-/2,7- (nos. 6/12), 2,6-1,7- (nos. 11/8) of diCNs; 1,3,6-/1,3,5- (nos. 20/19), 1,3,7-/1,4,6- (nos. 23/24), 1,6,7-/2,3,6- (nos. 25/26) of triCNs; 1,2,5,7-/1,2,4,6-/1,2,4,7- (nos. 37/33/34), 1,3,6,8-/1,2,5,6- (nos. 45/36), 1,2,3,5-/1,3,5,8- (nos. 28/43), 1,2,3,4-/1,2,3,7- (nos. 27/30), 1,2,5,8-/1,2,6,8- (nos. 38/40) of tetraCNs; 1,2,3,5,7-/1,2,4,6,7- (nos. 52/60), 1,2,3,5,8-/1,2,3,6,8- (nos. 53/55) of pentaCNs; 1,2,3,4,6,7-/1,2,3,5,6,7- (nos. 66/67), 1,2,3,4,5,7-/1,2,3,5,6,8- (64/68) and 1,2,4,5,6,8-/1,2,4,5,7,8- (nos. 71/72) of hexaCNs. Absent in the Halowaxes were CN congeners such as 1,3,8-triCN (no. 22) (<0.0002 mg/g), 1,3,6,7-tetraCN (no. 44), 1,2,3,6-TetraCN (no. 29), 1,2,3,6,7-pentaCN (no. 54) and 1,2,3,6,7,8-hexaCN (no. 70) (<0.0005 mg/g).

Chemical Industry↗

PubMed2006

Effects of antibacterial agents, levofloxacin and clarithromycin, on aquatic organisms.

Contamination of surface waters by pharmaceutical chemicals is an emerging environmental problem. This study evaluated the toxic effects of the antibacterial agents levofloxacin (LVFX) and clarithromycin (CAM), which are widely used in Japan, on aquatic organisms. Ecotoxicity tests using a bacterium, alga and crustacean were conducted. Microtox test using a marine fluorescent bacterium showed that LVFX and CAM have no acute toxicity to the bacterium. From the results of the Daphnia immobilisation test, LVFX and CAM did not show acute toxicity to the crustacean. Meanwhile, an algal growth inhibition test revealed that LVFX and CAM have high toxicity to the microalga. The phytotoxicity of CAM was about 100-fold higher than that of LVFX from a comparison of EC50 (median effective concentration) value. From the Daphnia reproduction test, LVFX and CAM also showed chronic toxicity to the crustacean. Concentrations of LVFX and CAM in the aquatic environment were compared with PNEC (predicted no effect concentration) to evaluate the ecological risk. As a result, the ecological risk of LVFX is considered to be low, but that of CAM is higher, suggesting that CAM discharged into an aquatic environment after therapeutic use may affect organisms in the aquatic environment.

Animals↗

PubMed2006

A single base insertion of the 4-alpha-galactosyltransferase gene led to the deficiency of Gb3 biosynthesis.

cDNAs for alpha 1,4 galactosyltransferase (A4GALT) have been isolated. To explore the molecular basis of the p phenotype in Japanese donors, we analyzed the A4GALT gene sequences of normal and p phenotype samples. The coding region in the A4GALT gene for DNA sequencing was amplified by PCR amplification. A4GALT expression vectors for individual were constructed by PCR amplification of the coding region using primers and subsequent subcloning into an expression vector. The expression of Gb3/CD77 antigen on the cell surface was evaluated by flow cytometry and by immunochemical techniques. All individuals with the p phenotype were found to have a single base insertion (A4GALT/insC) at the same nucleotide position. Neither the transfectant cells with a mutant gene (A4GALT/insC) of donor origin or those with a synthesized mutant gene (A4GALT/insC-Mu) expressed Gb3 antigen indicating that the presence of A4GALT/insC diminished the A4GALT enzyme activity. In addition, an allele-specific PCR (ASP) system was developed in which of the p phenotype with A4GALT/insC can be unambiguously discriminated from normal donors. Based on the finding that a single base insertion (A4GALT/insC) diminishes A4GALT activity, an ASP assay was developed to detect individuals with this particular p phenotype.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed2006

[Torsion of the right upper lobe due to primary lung cancer with pulmonary hypertrophic osteoarthropathy; report of a case].

A 61-year-old woman was admitted due to severe coughing. Chest X-ray revealed a mass in the right lower lung field at standing position and in the right upper lung field at supine position. A position of the mass changed with change in her posture because of lobar torsion. Bronchoscopic biopsy of the polypoid tumor obstructing the right upper bronchus revealed adenocarcinoma. She had hypertrophic osteoarthropathy simultaneously. Right pneumonectomy was performed. Postoperative course has been uneventful for 3 years.

Adenocarcinoma↗

PubMed2005

Alkaline digestion and solid phase extraction method for perfluorinated compounds in mussels and oysters from South China and Japan.

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS), have been identified in the coastal waters of China and Japan. An alkaline digestion method, coupled with solid-phase extraction (SPE), and high-performance liquid chromatography interfaced with high-resolution electrospray tandem mass spectrometry was developed to determine PFCs in mussel and oyster samples from coastal waters of South China and Japan. These techniques produced adequate recoveries and reporting limits with small quantities of PFCs. Concentrations of individual PFCs in mussels and oysters from South China and Japan ranged from 113.6 to 586.0 pg/g, wet weight (ww) for PFOS, 63.1 to 511.6 pg/g, ww for perfluorohexane sulfonate, 9.3 to 30.1 pg/g, ww for perfluorobutane sulfonate and 37.8 to 2957.0 pg/g, ww for perfluorooctane sulfonamide. The quantification of perfluorinated carboxylates was compromised by interferences from carboxylates in the procedural blanks. Perfluoroundecanoate and perfluorononanoate had relatively great blank interferences, which resulted in relatively poor limits of quantification for these compounds. Some PFCs were only identified in a limited number of samples: perfluorododecanoate in samples from Tokyo Bay, Japan (195.9 pg/g, ww); and perfluorodecanoate in Fuzhou, China (131.7 pg/g, ww) and Tokyo Bay (118.6 pg/g, ww). The greatest concentrations of perfluorooctanoate, perfluoroheptanoate, and perfluorohexanoate were observed in samples from Tokyo Bay and Bei Hai, South China.

Animals↗

PubMed2005

Trifluoroacetate profiles in the Arctic, Atlantic, and Pacific Oceans.

A series of depth profiles was collected at 22 sites in the Arctic, North and South Atlantic, and Pacific Oceans to determine spatial patterns for trifluoroacetate (TFA) concentrations in the marine environment and to investigate possible natural sources of TFA. Profiles were also taken over underwater vents in the North and South Pacific and the Mediterranean Sea. At the profile sites, TFA values ranged from <10 ng/L in the Pacific Ocean to greater than 150 ng/L in the Atlantic Ocean. Samples from the Canada Basin of the Arctic Ocean exhibited variable TFA concentrations (60-160 ng/L) down to 700 m. Below this depth, in water having 14C ages exceeding 1000 years, the TFA concentrations were constant (150 ng/L). Water returning to the Atlantic through the Canadian Arctic Archipelago had constant high TFA values. Profiles from the Northern Atlantic exhibited high values at all depths but were more consistent in the Western Atlantic. The northwestern Pacific Ocean surface profile sites exhibited low TFA concentrations in the top 100 m increasing to a maximum of 60 ng/L with depth. Samples from the South Pacific Ocean site had generally low values with a few depths (>800 m) having concentrations of 50 ng/L or more. To determine if underwater vents could contribute to the TFA concentrations in the oceans, profiles were taken over three vents in the Pacific and Mediterranean Oceans. The results suggest that some deep-sea vents may be natural sources of TFA.

Arctic Regions↗

PubMed2005

Human health risk assessment of organochlorines associated with fish consumption in a coastal city in China.

Food consumption is an important route of human exposure to organochlorines (OCs). In order to assess the potential health risks associated with these contaminants due to fish consumption, five species of fish were collected from a local market in Zhoushan City, an island in the East China Sea. Dioxin-like compounds, such as polychlorinated dibenzo-p-dioxins/ dibenzofurans, in the fish samples were screened by H4IIE-luc cell bioassay, and the concentrations of specific organochlorines were measured by gas chromatograph-electron capture detector (GC-ECD). The bioassay results indicated that concentrations of dioxin-like compounds in the fish samples were below detection limit (0.64 pg/mL). The concentrations of OC pesticides and PCBs ranged from 0.67 to 13 and 0.24 to 1.4 ng/g wet wt., respectively. Significantly, concentrations of p,p'-DDE in fish meat were comparatively high (average 3.9 ng/g wet wt.) compared with the other OC pesticides. The daily fish consumption, based on a dietary survey conducted among 160 local healthy residents, was determined to be 105 g/person. The relevant cancer benchmark concentrations of HCB, dieldrin, chlordane, DDTs and PCBs were 0.36, 0.04, 1.6, 1.7, and 0.29 ng/kg per day, respectively, based on the local diet. The hazard ratios (HRs), based on non-cancer endpoints were all less than 1.0, while the HRs based on cancer were greater than 1.0 for certain contaminants based on the 95th centile concentration in fish tissue.

Adult↗

PubMed2005

Clophen A60 composition and content of CBs, CNs, CDFs, and CDDs after 2D-HPLC, HRGC/LRMS, and HRGC/HRMS separation and quantification.

Chlorobiphenyl (CB) and by-side chlorodibenzofuran (CDF), chlorodibenzo-p-dioxin (CDD), and chloronaphthalene (CN) homologue group and congener composition, and concentrations have been examined in technical CBs mixture Clophen A60. 101 peaks representing 116 CB congeners were quantified in Clophen A60, and most contributing were CBs nos. 138, 153,134/144/149, and 180 with 15.4, 12.3,8.2, and 6.5%, respectively. Di-, tri-, tetra-, penta-, hexa-, hepta-, and octa-CBs constituted, respectively, 0.03, 0.03, 0.32, 9.9, 52.7, and 4.9% of chlorobiphenyls content of the Clophen A60, while mono-, nona-, and decaCB were not quantified. Tetra- to octaCDDs were absent in Clophen A60 at concentration above the method limit of quantification of <0.01 microg/g, while the total CDFs and CNs were found at 12 and 42 microg/g, respectively. Tetra-, penta-, hexa-, and hepta-CDF with 27, 46, 19, and 7% contribution, respectively, dominated in homologue group profile of CDFs, while octa-CDF was absent in Clophen A60. In compositional profile of CDF congeners the most abundant were 1,2,4,7,8-PeCDF, 2,3,4,7,8-PeCDF, and 1,2,3,4,7,8-HxCDF and each had >5% contribution. Amongst the CN homologue groups the profile in descending order followed by hepta-, hexa-, octa-, and penta-CNs with 56, 26, 16, and 2%, respectively. In compositional profile of CNs the most abundant were the congeners such as 1,2,3,4,5,6,7-HpCN (no. 73), 1,2,3,4,6,7-/1,2,3,5,6,7-HxCN (nos. 66/67), and 1,2,3,4,5,6,7,8-OcCN (no. 75) with 55, 21, and 16%, respectively. In terms of dioxin-like toxicity of Clophen A60 the contribution from planar non-ortho and mono-ortho CBs, CDFs, and CNs was 5280, 594.5, and 33.1 ng TCDD TEQ/g, respectively, and the total TEQ of planar analogues was 5908 ng/g.

Benzofurans↗

PubMed2004

Changes in microporosity and CH4 adsorptivity of preoxidized pitch-based activated carbon fibers by Mg deposition.

Magnesium oxide/hydroxide was deposited on pitch-based activated carbon fibers which were previously oxidized in air at different temperatures, and the changes in carbon oxidation activity, microporosity, and CH4 adsorptivity of the parent carbons due to Mg deposition were examined. DTA results, chemical analysis, and DRIFT spectra indicate that Mg species are mainly supported on the -COOH groups of the parent carbons, which serve as the catalysts to improve the oxidation activity of carbon. Mg deposition either increases or decreases the specific surface area, pore volume, and average micropore width of the parent carbon depending on the preoxidation temperatures. Mg deposition does not simply enhance CH4 adsorptivity: the complex changes are due to the differences in the supporting states of Mg species and slight modifications in micropore structure.

Journal Article↗

PubMed2004

Air oxidation effects on microporosity, surface property, and CH4 adsorptivity of pitch-based activated carbon fibers.

The changes in microporous structure and surface properties of pitch-based activated carbon fibers upon air oxidation were examined by high-resolution N2 adsorption and various physicochemical methods such as DTA, DRIFT, XPS, and chemical titration/analysis. It was found that air oxidation below 673 K slightly modifies the microporous structure together with a minor replacement of surface -C=O groups by -C-O groups. However, oxidation above 773 K gradually increases the specific surface area and the average width of micropores by producing micropores with larger widths and greatly induces the formation of surface functional groups, especially the -COOH group. A slight change in microporosities has an evident effect on CH4 storage property.

Journal Article↗

PubMed2004

Perfluorinated compounds in coastal waters of Hong Kong, South China, and Korea.

Perfluorinated compounds (PFCs), such as perfluorooctanesulfonate (PFOS) and related compounds, have recently been identified in the environment. PFOS, the terminal degradation product of many of the PFCs, has been found globally in many wildlife species, as well as open ocean waters, even in remote regions far from sources. In this study, a solid-phase extraction procedure coupled with high-performance liquid chromatography interfaced to high-resolution mass spectrometry was used to isolate, identify, and quantify small concentrations of PFCs in seawater. These techniques were applied to investigate the local sources of PFCs in several industrialized areas of Asia and provide information on how the PFCs are circulated by coastal currents. Ranges of concentrations of PFOS in coastal seawaters of Hong Kong, the Pearl River Delta, including the South China Sea, and Korea were 0.09-3.1, 0.02-12, and 0.04-730 pg/mL, respectively, while those of perfluorooctanoic acid (PFOA) were 0.73-5.5, 0.24-16, and 0.24-320 pg/mL, respectively. Potential sources of PFCs include major industrialized areas along the Pearl River Delta of southern China and major cities of Korea, which are several of the fastest growing industrial and economic regions in the world. Detectable concentrations of PFOS and PFOA in waters of southern China were similar to those in the coastal marine environment of Japan and certain regions in Korea. Concentrations of PFCs in several locations in Korean waters were 10-100-fold greater than those in the other locations on which we report here. The spatial and seasonal variations in PFC concentrations in surface seawaters in the Pearl River Delta and South China Sea indicate the strong influence of the Pearl River discharge on the magnitude and extent of PFC contamination in southern China. All of the concentrations of PFOS were less than those that would be expected to cause adverse effects to aquatic organisms or their predators except for one location in Korea adjacent to an industrialized area. Hazard quotients were from <0.001 to 0.002 for aquatic animals and ranged from <0.001 to 17 for predatory birds.

Alkanesulfonic Acids↗

PubMed2004

Gaseous adsorption properties of a silica-pillared layered manganese oxide.

Adsorptions of N(2), H(2)O, and organic vapors including CH(2)Cl(2), CCl(4), c-C(6)H(12), C(6)H(6), n-C(6)H(14), and n-C(9)H(20) on a silica-pillared layered manganese oxide (SiHMnO) and nonane-preadsorbed SiHMnO were examined. It is found that SiHMnO has a microporosity with a wide pore width distribution showing different pore wall affinities. Micropores with smaller width preferentially accommodate the nonane preadsorbate while the surface hydrophilicity of pore wall leads to an easier detachment of the adsorbed nonane molecules. H(2)O adsorption influences both the porosity and the surface properties by accelerating a sufficient hydrolysis of the remained TEOS molecules in SiHMnO. Examinations using Dubinin-Radeshkevich (DR) equation and isosteric heat of adsorption of organic molecules provide evidences that the wall surface of micropores with smaller and larger width have less affinity toward nonpolar and polar organic vapors, respectively.

Journal Article↗

PubMed2004

Polychlorinated naphthalenes and polychlorinated biphenyls in benthic organisms of a Great Lakes food chain.

Invasion of zebra mussels, Dreissena polymorpha, and round gobies, Neogobius melanostomus, into the Great Lakes has altered the food web structure and thereby the pathways of toxic contaminants such as polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). In this study, concentrations of PCNs and PCBs were measured in organisms of a Great Lakes benthic food chain encompassing zebra mussels. PCNs were found in all of the benthic organisms, including phytoplankton, algae, amphipods, zebra mussels, round goby, and smallmouth bass, Micropterus dolomieui. Concentrations of PCNs were greater in samples collected from the Raisin River than in samples from the St. Clair River. Biomagnification factors (BMF) for tetra- through octa-CN congeners in going from algae to zebra mussels from the St. Clair River ranged from 3 to 10. No major biomagnification of PCNs was found in round gobies, when concentrations were related to those in their prey species, zebra mussels. The biomagnification potential of PCNs appears to be similar to that of PCBs in the benthic food chain investigated in this study, despite the fact that PCNs may be metabolized by organisms higher in the food chain. Among several congeners, the BMFs of PCN congeners 35, 42, 43/45, 52/60, 58, and 66/67 were highest in round gobies. PCNs accounted for 1-22% of the total TEQs (toxic equivalents) of PCBs and PCNs in benthic organisms analyzed in this study. PCB congener 126 was the major contributor to TEQs, accounting for 72-99% of the PCB-TEQs in the food chain organisms analyzed.

Amphipoda↗

PubMed2004

Concentrations and fluxes of chloronaphthalenes in sediment from Lake Kitaura in Japan in past 15 centuries.

The concentrations of 63 congeners of chloronaphthalene (CN; polychlorinated naphthalenes, PCNs) in dated on approximately 500 B.C. to 2000 sediment core from the Lake Kitaura in Japan have been quantified by HRGC/HRMS after double column HPLC fractionation. Sediment from the Lake Kitaura showed a time-dependent pattern in distribution of CNs since the approximately 500 B.C. Starting from the 1910s the total CNs content increased accelerating from the 1960s, and, in parallel, the pattern of CN congeners has changed with a substantial increase in contribution from the penta, hexa, hepta, and octaCN. The total CNs content normalized to dry weight of sediment peaked out in the layer dated on 1984-1985, and next nearly two-fold decreased with further gradually decreasing concentration in 1987-2000. An occurrence of tri and tetraCNs in deep sediment layers corresponded to preindustrial synthesis and use of CNs seems to be connected to relatively greater water solubility and mobility in the pore water of those CN homologue groups. Based on CN congener pattern and results of multivariate analysis three main layers were separated in the sediment core. Starting from 1981 the emission sources related to combustion marker congeners become substantial contributors to flux of annually deposited CNs, while relative significance of the evaporative source marker congeners decreased after 1985. The annual flux of CNs into sediments of the Lake Kitaura was 0.073-0.31 pg/cm2 before 1926, increased to 5.5-14 pg/cm2 in 1963-1970 and next sharply increased to 50-107 pg/ cm2 in 1971-1985, and after that decreased to 17 pg/cm2 in 1997-2000.

Chlorine Compounds↗

PubMed2004

Highly toxic chlorobiphenyl and by-side impurities content and composition of technical chlorofen formulation.

Non- and mono-ortho CBs as well as also highly toxic by-side impurities such as chlorodibenzofurans, chlorodibenzo-p-dioxins, and chloronaphthalenes after a subsequent 2D-HPLC and HRGC-HRMS separation, detection, and identification were quantified in technical chlorobiphenyl Chlorofen formulation. Chlorofen is highly chlorinated CB mixture and its compositional profile of mono-ortho CBs is occupied by 2,3,3',4,4',5'-HxCB (no. 157) with 96.6% and followed by 2,3,3',4,4',5-HxCB (no. 156) with 3.3% and 2,3',4,4',5,5'-HxCB (no. 167) with <0.1%, while nos. 105, 114, 118, 123, and 189 remained undetected (<10 microg/g). Amongst non-ortho CBs only a trace of 3,3',4,4'-TeCB (no. 77) was found at 15 microg/g, while CBs nos. 81, 126, and 169 were absent. TCDD TEQ for mono- and non-ortho CBs in Chlorofen was 2320 and 1.5 ng/g, respectively, while for CDFs and CNs were 45 and 731 ng/g, respectively, and for both types of contaminants most contributing were OcCDF and OcCN. No tetra- to OcCDD was found in Chlorofen.

Chemical Industry↗

PubMed2003

Prostaglandin E2 induced the differentiation of osteoclasts in mouse osteoblast-depleted bone marrow cells.

Prostaglandin (PG) E(2) is a known bone absorbing agent that acts on osteoblasts to facilitate osteoclastogenesis by increasing the secretion of RANKL. In the present study, we investigated the direct action of PGE(2) on osteoclastic progenitors that differentiate into TRAP-positive multinucleated cells. The hematopoietic stem cell obtained from murine bone marrow was purified by a Sephadex G-10 column, and cultured in the presence of CSF-1 and RANKL to facilitate cell differentiation. The introduction of low-density PGE(2) into the culture resulted in a drastic increase of TRAP-positive multinucleated cells, whereas the addition of high-density PGE(2) had the opposite effect. PCR analysis revealed increased level of EP3 mRNA in undifferentiated cells and reduced level after the development of osteoclast; EP1, EP2 and EP4 were constitutively expressed throughout the differentiation. Investigation of intracellular signaling verified that low-density PGE(2) suppressed PKA activity in undifferentiated cells, suggesting that PGE(2) acts on the osteoclastic cell lineage to facilitate cell differentiation by suppressing PKA in the presence of RANKL.

Animals↗