The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Barbara F. Hales - One of the best experts on this subject based on the ideXlab platform.
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effects of organophosphate ester flame retardants on endochondral ossification in ex vivo murine limb Bud Cultures
Toxicological Sciences, 2019Co-Authors: Han Yan, Barbara F. HalesAbstract:Phasing out the usage of polybrominated diphenyl ether (PBDE) flame retardants (FRs) in consumer products led to their widespread replacement with organophosphate ester (OPE) FRs, despite scarce safety data. PBDE exposures were associated with the suppression of endochondral ossification but little is known about the effects of OPEs on bones. Here, we used a novel ex vivo murine limb Bud Culture system to compare the effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) with those of several OPEs. Gestation day 13 embryos were collected from transgenic CD1 mice expressing fluorescent markers for the major stages of endochondral ossification: COL2A1-ECFP (chondrogenesis), COL10A1-mCherry (early osteogenesis), and COL1A1-YFP (late osteogenesis). Limbs were excised and Cultured for 6 days in the presence of vehicle, BDE-47, or an OPE FR: triphenyl phosphate (TPHP), tert-butylphenyl diphenyl phosphate (BPDP), tris(methylphenyl) phosphate (TMPP), or isopropylated triphenyl phosphate (IPPP). BDE-47 (50 μM) decreased the extent of chondrogenesis in the digits and COL1A1-YFP expression in the radius and ulna relative to control. In comparison, concentrations of ≥1 μM of all 4 OPEs limited chondrogenesis; osteogenesis (both COL10A1-mCherry and COL1A1-YFP fluorescence) was markedly inhibited at concentrations ≥3 μM. The expression of Sox9, the master regulator of chondrogenesis, was altered by BDE-47, TPHP, and BPDP. BDE-47 exposure had minimal impact on the expression of Runx2 and Sp7, which drive osteogenesis, whereas TPHP and BPDP both suppressed the expression of these transcription factors. These data suggest that OPE FRs may be more detrimental to bone formation than their brominated predecessors.
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Assessment of the developmental toxicity of nanoparticles in an ex vivo 3D model, the murine limb Bud Culture system
Nanotoxicology, 2014Co-Authors: Emilia Bigaeva, France-hélène Paradis, Alexandre Moquin, Barbara F. Hales, Dusica MaysingerAbstract:AbstractThe rapid growth of nanotechnological products for biomedical applications has exacerbated the need for suitable biological tests to evaluate the potential toxic effects of nanomaterials. The possible consequences of exposure during embryo and fetal development are of particular concern. The limb Bud Culture is an ex vivo 3D model in which growth, cell differentiation, and tissue organization occur and both molecular and functional endpoints can be quantitatively assessed. We employed this model to assess biochemical and morphological changes induced during organogenesis by two classes of nanostructured materials: quantum dot nanocrystals and organic polyglycerol sulfate dendrimers (dPGS). We show that quantum dots carrying mercaptopropionic acid (QD-MPA) on the surface, commonly used in biological studies, inhibit the development of limb Buds from CD1 wildtype and Col2a1; Col10a1; Col1a1 triple transgenic fluorescent reporter mice, as revealed by changes in several morphological and biochemical m...
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The murine limb Bud in Culture as an in vitro teratogenicity test system.
Methods in molecular biology (Clifton N.J.), 2012Co-Authors: France-hélène Paradis, Chunwei Huang, Barbara F. HalesAbstract:There is widespread interest today in the use of in vitro methods to study normal and abnormal development. The limb is attractive in this context since much is known about pattern formation during limb development. The murine limb Bud Culture technique described in this chapter was developed and refined in the 1970s. In this Culture system, limb development mimics the in vivo process, although at a slower rate, where growth and cartilage differentiation lead to the formation of proximal and distal structures with an "in vivo-like" 3D shape. Uniform developmental stages are selected for assessment, exposures are controlled precisely, and the confounding influences of maternal metabolism and transport are avoided. The existence of transgenic mice with fluorescent markers for the different stages of endochondral ossification adds a further dimension to the technique by allowing striking time course observations of the developing limb. Today, limb Bud Cultures are used to study the roles of genes during embryogenesis and the mechanisms by which chemicals interfere with critical signalling pathways.
Craig L. Nessler - One of the best experts on this subject based on the ideXlab platform.
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clonal propagation of camptotheca acuminata through shoot Bud Culture
Plant Cell Tissue and Organ Culture, 1996Co-Authors: Ashok K Jain, Craig L. NesslerAbstract:The chinese tree Camptotheca acuminata produces the anti-cancer and anti-retroviral drug camptothecin. Methods were developed for the clonal propagation of this important medicinal plant through shoot Bud Culture. Shoot Buds were excised from 25 to 30 day old seedlings, presoaked for 48 h in three different liquid media containing either BA (2.22–17.4 μM), kinetin (2.32–18.58 μM), or thidiazuron (0.1–10 μM) and were subsequently Cultured on semi-solid medium of the same composition. Multiple shoots only developed from the 6-benzyladenine presoaked explants with the maximum number of shoots initiated from Buds presoaked in and grown on B5 medium containing 17.4 μM 6-benzyladenine. Individual shoots were removed from clusters and rooted on B5 supplemented with indole-3-butyric acid (4.9–19.6 μM). The lowest concentration of indole-3-butyric acid (4.9 μM) gave the highest percentage of rooting (82%) and the shortest root initiation period (18 d). Over 90% of the in vitro rooted plantlets survived transfer to soil.
Z. H. Cai - One of the best experts on this subject based on the ideXlab platform.
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Autotetraploid plants from colchicine-treated Bud Culture of Salvia miltiorrhiza Bge
Plant Cell Tissue and Organ Culture, 1996Co-Authors: S. L. Gao, D. N. Zhu, Z. H. CaiAbstract:The root ofSalvia miltiorrhiza is a traditional Chinese medicinal plant used as an important drug to cure cardiovascular diseases. Research on the technology of induction, identification and chemical analysis of polypoid plants is reported. The obtained results indicated that basal MS media plus 10 ppm colchicine can induce polyploid mutants effectively. Tetraploid plants were transferred to the fields so that comparative experiment for further identification, observation and screening of 15 agronomic characteristics could be made. The major chemical compounds, tanshinones, in two tetraploid plants were higher than that in the control. An excellent plant 61-2-22 may develop into a new variety for large scale production.
Ashok K Jain - One of the best experts on this subject based on the ideXlab platform.
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clonal propagation of camptotheca acuminata through shoot Bud Culture
Plant Cell Tissue and Organ Culture, 1996Co-Authors: Ashok K Jain, Craig L. NesslerAbstract:The chinese tree Camptotheca acuminata produces the anti-cancer and anti-retroviral drug camptothecin. Methods were developed for the clonal propagation of this important medicinal plant through shoot Bud Culture. Shoot Buds were excised from 25 to 30 day old seedlings, presoaked for 48 h in three different liquid media containing either BA (2.22–17.4 μM), kinetin (2.32–18.58 μM), or thidiazuron (0.1–10 μM) and were subsequently Cultured on semi-solid medium of the same composition. Multiple shoots only developed from the 6-benzyladenine presoaked explants with the maximum number of shoots initiated from Buds presoaked in and grown on B5 medium containing 17.4 μM 6-benzyladenine. Individual shoots were removed from clusters and rooted on B5 supplemented with indole-3-butyric acid (4.9–19.6 μM). The lowest concentration of indole-3-butyric acid (4.9 μM) gave the highest percentage of rooting (82%) and the shortest root initiation period (18 d). Over 90% of the in vitro rooted plantlets survived transfer to soil.
France-hélène Paradis - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the developmental toxicity of nanoparticles in an ex vivo 3D model, the murine limb Bud Culture system
Nanotoxicology, 2014Co-Authors: Emilia Bigaeva, France-hélène Paradis, Alexandre Moquin, Barbara F. Hales, Dusica MaysingerAbstract:AbstractThe rapid growth of nanotechnological products for biomedical applications has exacerbated the need for suitable biological tests to evaluate the potential toxic effects of nanomaterials. The possible consequences of exposure during embryo and fetal development are of particular concern. The limb Bud Culture is an ex vivo 3D model in which growth, cell differentiation, and tissue organization occur and both molecular and functional endpoints can be quantitatively assessed. We employed this model to assess biochemical and morphological changes induced during organogenesis by two classes of nanostructured materials: quantum dot nanocrystals and organic polyglycerol sulfate dendrimers (dPGS). We show that quantum dots carrying mercaptopropionic acid (QD-MPA) on the surface, commonly used in biological studies, inhibit the development of limb Buds from CD1 wildtype and Col2a1; Col10a1; Col1a1 triple transgenic fluorescent reporter mice, as revealed by changes in several morphological and biochemical m...
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The murine limb Bud in Culture as an in vitro teratogenicity test system.
Methods in molecular biology (Clifton N.J.), 2012Co-Authors: France-hélène Paradis, Chunwei Huang, Barbara F. HalesAbstract:There is widespread interest today in the use of in vitro methods to study normal and abnormal development. The limb is attractive in this context since much is known about pattern formation during limb development. The murine limb Bud Culture technique described in this chapter was developed and refined in the 1970s. In this Culture system, limb development mimics the in vivo process, although at a slower rate, where growth and cartilage differentiation lead to the formation of proximal and distal structures with an "in vivo-like" 3D shape. Uniform developmental stages are selected for assessment, exposures are controlled precisely, and the confounding influences of maternal metabolism and transport are avoided. The existence of transgenic mice with fluorescent markers for the different stages of endochondral ossification adds a further dimension to the technique by allowing striking time course observations of the developing limb. Today, limb Bud Cultures are used to study the roles of genes during embryogenesis and the mechanisms by which chemicals interfere with critical signalling pathways.
