ABSTRACT
Surface modification of superparamagnetic Fe3O4 nanoparticles using polymers (polyaniline/polypyrrole) was done by radio frequency (r.f.) plasma polymerization technique and characterized by XRD, TEM, TG/DTA and VSM. Surface-passivated Fe3O4 nanoparticles with polymers were having spherical/rod-shaped structures with superparamagnetic properties. Broad visible photoluminescence emission bands were observed at 445 and 580 nm for polyaniline-coated Fe3O4 and at 488 nm for polypyrrole-coated Fe3O4. These samples exhibit good fluorescence emissions with L929 cellular assay and were non-toxic. Magnetic hyperthermia response of Fe3O4 and polymer (polyaniline/polypyrrole)-coated Fe3O4 was evaluated and all the samples exhibit hyperthermia activity in the range of 42-45 °C. Specific loss power (SLP) values of polyaniline and polypyrrole-coated Fe3O4 nanoparticles (5 and 10 mg/ml) exhibit a controlled heat generation with an increase in the magnetic field.
Subject(s)
Aniline Compounds/chemistry , Diagnostic Imaging/methods , Hyperthermia, Induced/methods , Magnetite Nanoparticles/chemistry , Polymers/chemistry , Pyrroles/chemistry , Aniline Compounds/radiation effects , Cell Line, Tumor , Cell Survival/drug effects , Ferric Compounds/chemical synthesis , Ferric Compounds/chemistry , Ferric Compounds/radiation effects , Humans , Magnetic Fields , Magnetics/methods , Magnetite Nanoparticles/radiation effects , Magnetite Nanoparticles/therapeutic use , Materials Testing , Plasma Gases/chemistry , Polymers/radiation effects , Pyrroles/radiation effects , Radio Waves , Surface Properties/radiation effects , X-Ray DiffractionABSTRACT
Artistic creativity can emerge in patients with Parkinson's disease. Here we describe two patients who had creative awakening while on levodopa treatment for Parkinson's disease and discuss its implications.
Subject(s)
Creativity , Dopamine Agents/pharmacology , Levodopa/pharmacology , Parkinson Disease/drug therapy , Aged , Humans , Male , Middle Aged , Qualitative ResearchABSTRACT
In the neurogenic areas of the adult rodent brain, neural stem cells (NSCs) proliferate and produce new neurons throughout the lifetime. This requires a permanent pool of NSCs, the size of which needs to be tightly controlled. The gp130-associated cytokines ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) have been implicated in regulating NSC self-renewal and differentiation during embryonic development and in the adult brain. To study the relevance of the two cytokines in vivo, we analyzed precursor cell proliferation and neurogenesis in the dentate gyrus of CNTF- and LIF-deficient mouse mutants. The number of radial glia-like NSCs, proliferative activity, and generation of new neurons were all reduced in CNTF(-/-) mutants but unaltered in LIF(-/-) animals. Conditional ablation of the signal transducer and activator of transcription 3 (STAT3) gene under the control of the human glial fibrillary acidic protein promoter resulted in a reduction of neurogenesis similar to that in CNTF(-/-) mice. The size of the granule cell layer was decreased in both mutants. Treatment of neurosphere cultures prepared from adult forebrain with CNTF inhibited overall proliferative activity but increased the number of NSCs as indicated by enhanced secondary neurosphere formation and upregulated expression of stem cell markers. Knockdown of STAT3 with short interfering RNA inhibited CNTF effects on neurospheres, and knockdown of suppressor of cytokine signaling 3 (SOCS3) enhanced them. Our results provide evidence that CNTF-induced STAT3 signaling is essential for the formation and/or maintenance of the neurogenic subgranular zone in the adult dentate gyrus and suggest that CNTF is required to keep the balance between NSC self-renewal and the generation of neuronal progenitors.
Subject(s)
Ciliary Neurotrophic Factor/pharmacology , Ciliary Neurotrophic Factor/physiology , Dentate Gyrus/cytology , Dentate Gyrus/metabolism , Neurogenesis/physiology , STAT3 Transcription Factor/metabolism , Signal Transduction , Animals , Cell Proliferation/drug effects , Cells, Cultured , Ciliary Neurotrophic Factor/genetics , Immunohistochemistry , Leukemia Inhibitory Factor/genetics , Leukemia Inhibitory Factor/physiology , Mice , Mice, Mutant Strains , Neurogenesis/genetics , Neurons/cytology , STAT3 Transcription Factor/genetics , Stem Cells/cytology , Stem Cells/drug effects , Stem Cells/metabolismABSTRACT
Most drugs and xenobiotics induce the expression of cytochrome P450 (CYP) enzymes, which reduce the bioavailability of the inducer and/or co-administered drugs. Therefore, evaluation of new drug candidates for their effect on CYP expression is an essential step in drug development. The available methods for this purpose are expensive and not amenable to high-throughput screening. We developed a fluorescence-based in vivo assay using transgenic Caenorhabditis elegans worms that express the green fluorescent protein (GFP) under the control of various CYP promoters. Using this assay, we found striking similarities between the worm CYPs and their human orthologs in their response to treatment with various drugs. For example,the antibiotic rifampicin, one of the strongest inducers of the human gene CYP3A4, was the strongest inducer of the worm ortholog CYP13A7. Since worms can be easily grown in liquid medium in microtitre plates, the assay described in this paper is suitable for the screening of a large number of potential lead compounds in the drug discovery process.
