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1.
J Environ Biol ; 36(5): 1193-7, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26521565

RESUMO

Indian shad, Tenualosa ilisha, is a commercially important anadromous fish representing major catch in Indo-pacific region. The present study evaluated partial Cytochrome b (Cyt b) gene sequence of mtDNA in T. ilisha for determining genetic variation from Bay of Bengal and Arabian Sea origins. The genomic DNA extracted from T. ilisha samples representing two distant rivers in the Indian subcontinent, the Bhagirathi (lower stretch of Ganges) and the Tapi was analyzed. Sequencing of 307 bp mtDNA Cytochrome b gene fragment revealed the presence of 5 haplotypes, with high haplotype diversity (Hd) of 0.9048 with variance 0.103 and low nucleotide diversity (π) of 0.14301. Three population specific haplotypes were observed in river Ganga and two haplotypes in river Tapi. Neighbour-joining tree based on Cytochrome b gene sequences of T. ilisha showed that population from Bay of Bengal and Arabian Sea origins belonged to two distinct clusters.


Assuntos
DNA Mitocondrial/genética , Peixes/genética , Variação Genética , Animais , Filogenia
2.
J Food Sci Technol ; 52(9): 5456-69, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26344961

RESUMO

High value fruits namely, apple (cv. Royal Delicious), guava (cv. Baruipur) and litchi (cv. Shahi) harvested at their commercial maturity were considered for MA packaging to enhance storage life. Polymeric films namely LDPE, BOPP, PVC, PVDC of different thickness were used for MA packaging study and various film characteristics such as gas transmission rates, water vapour transmission rate, clarity, strength and durability were evaluated. Mathematical model was developed based on Arrhenius type equation to predict gas transmission rate (GTR) and the developed model was found to be very good fit with the mean relative deviation modulus value quite less than 10 %. The GTR of the films increased with the increase in storage temperature and the magnitude of the increase varied with the film type and thickness. Regression models have been suitably developed to predict the oxygen transmission rate and carbon dioxide transmission rate of selected polymeric films and combined film laminates as a function of temperatures. Since, none of the individual films could meet the gas transmission requirements of MAP for selected fruits, two different films were tailored to form laminates that sufficed the requirements for prolonged storage with maintaining original quality.

4.
Plant Biol (Stuttg) ; 24(6): 920-931, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35727191

RESUMO

Incorporating C4 photosynthetic traits into C3 crops is a rational approach for sustaining future demands for crop productivity. Using classical plant breeding, engineering this complex trait is unlikely to achieve its target. Therefore, it is critical and timely to implement novel biotechnological crop improvement strategies to accomplish this goal. However, a fundamental understanding of C3 , C4 , and C3 -C4 intermediate metabolism is crucial for the targeted use of biotechnological tools. This review assesses recent progress towards engineering C4 photosynthetic traits in C3 crops. We also discuss lessons learned from successes and failures of recent genetic engineering attempts in C3 crops, highlighting the pros and cons of using rice as a model plant for short-, medium- and long-term goals of genetic engineering. This review provides an integrated approach towards engineering improved photosynthetic efficiency in C3 crops for sustaining food, fibre and fuel production around the globe.


Assuntos
Oryza , Melhoramento Vegetal , Produção Agrícola , Produtos Agrícolas/genética , Oryza/genética , Fotossíntese/genética , Folhas de Planta/metabolismo
5.
Methods Find Exp Clin Pharmacol ; 31(9): 571-84, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20094640

RESUMO

The folklore medicine of primitive people has been greatly appreciated for centuries. Many researchers study the curative efficiency and mode of action of various medicinal plants. Serum glucose level, lipid profile, glucose tolerance, hepatic and muscle glycogen contents as well as the activities of hepatic hexokinase and glucose-6-phosphatase recovered significantly after oral administration of ethyl acetate fractions of Eugenia jambolana (E. jambolana) or Musa paradisiaca (M. paradisiaca) in separate (E. jambolana L.: 200 mg/kg of body weight and M. paradisiaca: 100 mg/kg of body weight) or combined form for 90 days (twice a day through gavage) to streptozotocin-induced diabetic rats. The loss in body weight of diabetic animals was reversed and serum levels of insulin as well as C-peptide, which were found to be reduced in diabetic rats, increased significantly after oral administration of the fractions. A histological study of the rats' pancreas revealed that after 90 days of oral treatment with the plant fractions in separate or combined form, the size and volume of pancreatic islets in diabetic treated rats increased significantly compared with the diabetic control group. Treatment of diabetic rats with the combined dose (300 mg/kg of body weight) of plant fractions (200 mg E. jambolana and 100 mg M. paradisiaca) was found to be more effective than treatment with the individual fraction. The doses of E. jambolana and M. paradisiaca selected for this study are the optimum antihyperglycemic doses of the plant fractions, which were determined after conducting a dose-dependent study at various dose levels (50-500 mg/kg) in our pilot experiments. The plant fractions were found to be free from metabolic toxicity. Through HPTLC finger printing, three different compounds were noted in the ethyl acetate fraction of E. jambolana L. and eight different compounds in the ethyl acetate fraction of M. paradisiaca L.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Musa/química , Fitoterapia , Extratos Vegetais/uso terapêutico , Syzygium/química , Animais , Glicemia/análise , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Hexoquinase/metabolismo , Insulina/sangue , Lipídeos/sangue , Glicogênio Hepático/análise , Masculino , Raízes de Plantas/química , Ratos , Ratos Wistar , Sementes/química , Estreptozocina
6.
Mol Biol Cell ; 8(2): 353-65, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9190213

RESUMO

Tau is a neuronal microtubule-associated protein that promotes microtubule assembly, stability, and bundling in axons. Two distinct regions of tau are important for the tau-microtubule interaction, a relatively well-characterized "repeat region" in the carboxyl terminus (containing either three or four imperfect 18-amino acid repeats separated by 13- or 14-amino acid long inter-repeats) and a more centrally located, relatively poorly characterized proline-rich region. By using amino-terminal truncation analyses of tau, we have localized the microtubule binding activity of the proline-rich region to Lys215-Asn246 and identified a small sequence within this region, 215KKVAVVR221, that exerts a strong influence on microtubule binding and assembly in both three- and four-repeat tau isoforms. Site-directed mutagenesis experiments indicate that these capabilities are derived largely from Lys215/Lys216 and Arg221. In marked contrast to synthetic peptides corresponding to the repeat region, peptides corresponding to Lys215-Asn246 and Lys215-Thr222 alone possess little or no ability to promote microtubule assembly, and the peptide Lys215-Thr222 does not effectively suppress in vitro microtubule dynamics. However, combining the proline-rich region sequences (Lys215-Asn246) with their adjacent repeat region sequences within a single peptide (Lys215-Lys272) enhances microtubule assembly by 10-fold, suggesting intramolecular interactions between the proline-rich and repeat regions. Structural complexity in this region of tau also is suggested by sequential amino-terminal deletions through the proline-rich and repeat regions, which reveal an unusual pattern of loss and gain of function. Thus, these data lead to a model in which efficient microtubule binding and assembly activities by tau require intramolecular interactions between its repeat and proline-rich regions. This model, invoking structural complexity for the microtubule-bound conformation of tau, is fundamentally different from previous models of tau structure and function, which viewed tau as a simple linear array of independently acting tubulin-binding sites.


Assuntos
Microtúbulos/metabolismo , Prolina/metabolismo , Proteínas tau/metabolismo , Sequência de Aminoácidos , Asparagina , Sítios de Ligação , Lisina , Microtúbulos/fisiologia , Dados de Sequência Molecular , Peptídeos/síntese química , Peptídeos/química , Peptídeos/metabolismo , Domínios Proteicos Ricos em Prolina , Relação Estrutura-Atividade , Proteínas tau/química
7.
FEBS J ; 273(17): 4114-28, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16903866

RESUMO

We found that benomyl, a benzimidazole fungicide, strongly suppressed the reassembly of cold-depolymerized spindle microtubules in HeLa cells. Benomyl perturbed microtubule-kinetochore attachment and chromosome alignment at the metaphase plate. Benomyl also significantly decreased the distance between the sister kinetochore pairs in metaphase cells and increased the level of the checkpoint protein BubR1 at the kinetochore region, indicating that benomyl caused loss of tension across the kinetochores. In addition, benomyl decreased the intercentrosomal distance in mitotic HeLa cells and blocked the cells at mitosis. Further, we analyzed the effects of benomyl on the signal transduction pathways in relation to mitotic block, bcl2 phosphorylation and induction of apoptosis. The results suggest that benomyl causes loss of tension across the kinetochores, blocks the cell cycle progression at mitosis and subsequently, induces apoptosis through the bcl2-bax pathway in a manner qualitatively similar to the powerful microtubule targeted anticancer drugs like the vinca alkaloids and paclitaxel. Considering the very high toxicity of the potent anticancer drugs and the low toxicity of benomyl in humans, we suggest that benomyl could be useful as an adjuvant in combination with the powerful anticancer drugs in cancer therapy.


Assuntos
Apoptose/efeitos dos fármacos , Benomilo/farmacologia , Cinetocoros/efeitos dos fármacos , Microtúbulos/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Fungicidas Industriais/farmacologia , Células HeLa , Humanos , Cinetocoros/patologia , Mitose/efeitos dos fármacos
8.
Cancer Res ; 60(18): 5045-51, 2000 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11016627

RESUMO

Vinflunine is a novel Vinca alkaloid presently in Phase I clinical trials. In preclinical studies, it exhibited superior antitumor activity to that of other Vinca alkaloids, including vinorelbine from which it was synthetically derived. Vinca alkaloids appear to inhibit cell proliferation by affecting the dynamics of spindle microtubules. Here we have analyzed the effects of vinflunine and vinorelbine on microtubule dynamic instability and treadmilling and found that these newer drugs exert effects on microtubule dynamics that differ significantly from those of the classic Vinca alkaloid, vinblastine. The major effects of vinflunine and vinorelbine on dynamic instability were a slowing of the microtubule growth rate, an increase in growth duration, and a reduction in shortening duration. In marked contrast to the action of vinblastine, they neither reduced the rate of shortening nor increased the percentage of time the microtubules spent in an attenuated state, neither growing nor shortening detectably. In addition, vinflunine and vinorelbine suppressed treadmilling, but less strongly than vinblastine. The diverse actions of these drugs on microtubules are likely to produce different effects on mitotic spindle function, leading to different effects on cell cycle progression and cell killing. Nontumor cells with normal checkpoint proteins may tolerate the relatively less powerful inhibitory effects of vinflunine and vinorelbine on microtubule dynamics better than the more powerful effects of vinblastine. Thus the unique constellation of effects of vinflunine and vinorelbine on dynamic instability and treadmilling may contribute to their superior antitumor efficacies.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Microtúbulos/efeitos dos fármacos , Vimblastina/análogos & derivados , Vimblastina/farmacologia , Animais , Microtúbulos/metabolismo , Ouriços-do-Mar , Tubulina (Proteína)/metabolismo , Vinorelbina
9.
J Nanosci Nanotechnol ; 16(1): 1216-9, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27398590

RESUMO

Formation of tetralayer memory structure having nickel-germanide nanocrystals using a Ge/Ni multilayers is proposed. X-ray diffraction study shows the NiGe (002) phase formation after proper annealing. Cross sectional HRTEM clearly shows the sharpness and the size (~4-6 nm) of the stacked nanocrystals embedded in the oxide matrix. A large anti-clockwise hysteresis memory win- dow of 13.4 Volt at ± 15 Volt is observed for the optimized samples. This large memory window indicates for the MLC applications. Frequency independent C-V curve confirms about the charge storage in the nanocrystals. A good charge retention and endurance characteristics are exhibited upto 125 °C for the nonvolatile memory application.

10.
ACS Appl Mater Interfaces ; 8(9): 6127-36, 2016 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-26881895

RESUMO

An improvement in resistive switching (RS) characteristics of CeO2-based devices has been reported by charge transfer through Al metal as a dopant. Moreover, density functional theory (DFT) calculations have been performed to investigate the role of Al-layer sandwiched between CeO2 layers by the Vienna ab initio simulation package (VASP). Total density of states (TDOS) and partial electron density of states (PDOS) have been calculated and analyzed with respect to resistive switching. It is established that the oxygen vacancy based conductive filaments are formed and ruptured in the upper region of CeO2 layer, because of the fact that maximum transport of charge takes place in this region by Al and Ti (top electrode), while the lower region revealed less capability to generate conductive filaments because minimum charge transfer takes place in this region by Al and/or Pt (bottom electrode). The effect of Al and Al2O3 on both the electronic charge transfer from valence to conduction bands and the formation stability of oxygen vacancies in conductive filament have been discussed in detail. Experimental results demonstrated that the Ti/CeO2:Al/Pt sandwich structure exhibits significantly better switching characteristics including lower forming voltage, improved and stable SET/RESET voltages, enhanced endurance of more than 10(4) repetitive switching cycles and large memory window (ROFF/RON > 10(2)) as compared to undoped Ti/CeOx/Pt device. This improvement in memory switching behavior has been attributed to a significant decrease in the formation energy of oxygen vacancies and to the enhanced oxygen vacancies generation within the CeO2 layers owing to charge transferring and oxygen gettering ability of Al-dopant.

11.
J Colloid Interface Sci ; 283(2): 294-9, 2005 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-15721897

RESUMO

The adsorption behavior of polyoxyethylene (23) lauryl ether (Brij-35) and cetyl trimethyl ammonium bromide (CTAB) on coal sample has been studied. The adsorption process is found to be sensitive to pH, temperature, electrolyte concentration, and the amount of surface active agent. An attempt has been made to explain the adsorption behavior of the surfactants using the Langmuir equation. The extent of adsorption of Brij-35 on coal is found to be the highest at pH 2, which decreases with increase in pH and remains constant in the neutral and alkaline pH regions. But, the adsorption of CTAB exhibits the opposite behavior of that of Brij-35. Adsorption of any of the surfactant at the coal/water interface sharply decreases the apparent viscosity of 55 wt% coal-water slurry (CWS) at a shear rate of 100 s(-1). Electrostatic adsorption of the surfactants on the coal surface decreases the surface charge and renders the coal surface hydrophobic which is manifested in the form of high apparent viscosity of the coal-water slurry under the test conditions.

12.
J Bone Miner Res ; 16(1): 46-56, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11149489

RESUMO

The murine homologue of the 25-hydroxyvitamin D [25(OH)D] 1alpha-hydroxylase gene [1alpha(OH)ase; Cyp27bl], which is mutated in humans with vitamin D-dependent rickets type I (VDDR-I; also known as pseudovitamin D-deficiency rickets [PDDR]) was cloned and characterized. Like the human, the mouse gene has nine exons, and the exon-intron organization is well conserved. By interspecific backcross analysis, the Cyp27bl gene was mapped to 70.5 cM on mouse Chr 10. This is in a region syntenic with human Chr 12q13.1-q13.3 to which the human 1alpha(OH)ase gene was previously mapped. Kidney expression of the 1alpha(OH)ase was localized to cortical tubules and was higher in the adult mouse than in the fetus, consistent with the increased role of its product as a circulating hormone postnatally. Prenatally, the 1alpha(OH)ase gene, together with the vitamin D receptor (VDR) gene, was expressed in embryonic stem cells, and expression of 1alpha(OH)ase in bone and intestine was higher in the fetus than in the adult. These observations suggest that 1,25-dihydroxyvitamin D [1,25(OH)2D] plays a role in fetal development. In view of the fact that humans lacking 1alpha(OH)ase have apparently normal prenatal development, this may point to functional redundancy in the fetal vitamin D system, which now can be explored further in mouse models in which the 1alpha(OH)ase gene has been deleted.


Assuntos
25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Éxons/genética , Regulação da Expressão Gênica no Desenvolvimento , Mapeamento Físico do Cromossomo , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/química , Envelhecimento/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Osso e Ossos/embriologia , Osso e Ossos/metabolismo , Linhagem Celular , Clonagem Molecular , Sequência Conservada/genética , Feto/metabolismo , Perfilação da Expressão Gênica , Humanos , Hibridização In Situ , Mucosa Intestinal/metabolismo , Intestinos/embriologia , Íntrons/genética , Rim/embriologia , Rim/metabolismo , Camundongos , Camundongos Endogâmicos , Dados de Sequência Molecular , Oligonucleotídeos Antissenso , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Mapeamento por Restrição , Células-Tronco/metabolismo
13.
Endocrinology ; 142(2): 926-39, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11159866

RESUMO

To explore how the loss of Phex function contributes to the pathogenesis of osteomalacia, we examined the abnormalities of mineralization, Phex, and bone matrix protein expression occurring in Hyp mice in vivo and in ex vivo bone marrow cell cultures. The results in vivo show that mineralization was decreased significantly in Hyp mouse bone. Phex protein was identifiable in osteoblasts and osteocytes in wild-type mice, but not in Hyp mice. In Hyp mice, osteocalcin, bone sialoprotein, and vitronectin expression were down-regulated, whereas biglycan and fibrillin-1 expression were up-regulated in osteocytes and bone matrix relative to those in their wild-type counterparts. Parallel studies ex vivo demonstrated that cells derived from 18-day Hyp mouse bone marrow cell cultures had a 3'-Phex deletion, no Phex protein expression, decreased alkaline phosphatase activity, collagen deposition, and calcium accumulation, and reduced osteocalcin, bone sialoprotein, and vitronectin at both the protein and messenger RNA levels. Furthermore conditioned medium from Hyp mouse bone marrow cultures could induce analogous defects in bone marrow cell cultures of wild-type cells. These novel findings indicate that there is an intrinsic osteogenic cell differentiation defect in addition to the known hypomineralization of bone in Hyp mice, which may be inducible by an autocrine/paracrine secreted factor. These results suggest that alterations in the Phex gene may control bone matrix mineralization indirectly by regulating the synthesis and deposition of bone matrix proteins.


Assuntos
Matriz Óssea/metabolismo , Hipofosfatemia Familiar/complicações , Hipofosfatemia Familiar/metabolismo , Osteomalacia/etiologia , Proteínas/metabolismo , Animais , Biglicano , Densidade Óssea , Medula Óssea/metabolismo , Medula Óssea/patologia , Osso e Ossos/metabolismo , Diferenciação Celular , Células Cultivadas , Colágeno/metabolismo , Proteínas da Matriz Extracelular , Fibrilina-1 , Fibrilinas , Hipofosfatemia Familiar/genética , Hipofosfatemia Familiar/patologia , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/metabolismo , Osteoblastos/metabolismo , Osteocalcina/metabolismo , Osteócitos/metabolismo , Osteogênese/fisiologia , Endopeptidase Neutra Reguladora de Fosfato PHEX , Proteoglicanas/metabolismo , Valores de Referência , Distribuição Tecidual , Vitronectina/metabolismo
14.
Gene ; 105(1): 107-11, 1991 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-1936999

RESUMO

The lack of an efficient transformation system in Vibrio cholerae was a handicap in the genetic manipulation of this important human pathogen. Since V. cholerae cells secrete DNases, this may interfere with the uptake of DNA. The present report describes the approaches taken for transforming V. cholerae cells with plasmid DNA, by overcoming this DNase barrier. The partial success of transforming DNase-negative mutants confirmed the role of DNase in the nontransformability of the wild-type cells. Successful transformation was carried out following removal of DNases from the periplasmic space. This was achieved by treating the cells with Mg2+ and Ca2+ ions to allow the DNase to be released, and then holding them under conditions where the remaining DNase activity was minimized before adding DNA to the competent cells. Transformation efficiencies of the order of 10(-5) per recipient cell were observed.


Assuntos
Plasmídeos/genética , Transformação Bacteriana/genética , Vibrio cholerae/genética , Cálcio/farmacologia , Desoxirribonucleases/genética , Desoxirribonucleases/metabolismo , Cinética , Magnésio/farmacologia , Mutação/genética , Temperatura , Vibrio cholerae/efeitos dos fármacos
15.
Mutat Res ; 210(1): 149-56, 1989 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2642599

RESUMO

Attempts to identify an umuDC analog, using interspecific complementation of Escherichia coli mutants with plasmids containing a gene bank of Vibrio cholerae, were not successful. The DNA from none of the vibrio species examined including marine vibrios hybridized to E. coli umuC and umuD gene sequences. These cells are not mutable by ultraviolet (UV) light and cannot Weigle-reactivate UV-irradiated choleraphages, suggesting that vibrios are deficient in the umuDC operon. This possibility is supported by the fact that when the plasmid pKM101 carrying the mucAB genes is introduced into V. cholerae cells, they acquire the UV-mutable phenotype and UV-irradiated choleraphages can be Weigle-reactivated.


Assuntos
Reparo do DNA , Genes Bacterianos , Vibrio cholerae/genética , Southern Blotting , Escherichia coli/genética , Hibridização de Ácido Nucleico , Plasmídeos
16.
Vet Parasitol ; 44(3-4): 275-83, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1466134

RESUMO

Engorged female ticks of Boophilus microplus were exposed in wire-gauze cylinders and glass tubes in an experimental grass plot at monthly intervals during 1989, and egg laying, egg development and larval survival periods observed and recorded. Rainfall and atmospheric relative humidity had an important influence on tick activity. Egg production was maximum, hatching percentage was high, incubation and prehatch periods were short, and larval survival and total longevity periods were long for ticks exposed during the warm and humid rainy season from June to September. Dry atmospheric conditions severely affected egg development, egg hatch and larval survival. Eggs failed to hatch in the dry months from December to April and only 29-38% hatched after a long incubation period of 41 days in November and May. On grass, the larvae of ticks exposed in November survived for the shortest period of 28 days and the larvae of ticks exposed in June survived for the longest period of 133 days. Low winter temperatures reduced egg production and prolonged the pre-oviposition, oviposition and incubation periods. It is suggested that the results of this study might be helpful in the development of measures to control tick infestation by planned dipping and restricted grazing during the period from late June to January when the pasture has a substantial load of larval ticks.


Assuntos
Clima , Carrapatos/fisiologia , Animais , Feminino , Umidade , Índia , Longevidade , Oviposição , Chuva , Estações do Ano , Carrapatos/crescimento & desenvolvimento
17.
Stud Health Technol Inform ; 70: 327-33, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10977565

RESUMO

Medical data in image format continues to increase in both size and complexity. We have integrated advanced techniques in visualization, networked computing, and interface design to improve methods for accessing medical data comprising high-resolution images for reconstructions into three-dimensional volumetric representations. We present two approaches to handle the range of low to high-end client platforms, support visualization functionality, and provide the ability to manipulate very large data over heterogeneous computing and networking environments. We present examples of its use for clinical, research, and educational purposes and discuss future extensions.


Assuntos
Redes de Comunicação de Computadores , Processamento de Imagem Assistida por Computador , Sistemas Computadorizados de Registros Médicos , Interface Usuário-Computador , Humanos , Imageamento por Ressonância Magnética , Tomografia Computadorizada por Raios X
20.
J Biomed Mater Res B Appl Biomater ; 85(2): 409-16, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-17922528

RESUMO

La(1-x)Sr(x)MnO(3), a ferromagnet with high magnetization and Curie temperature T(C) below 70 degrees C, enables its use for magnetic hyperthermia treatment of cancer with a possibility of in vivo temperature control. We found that La(0.73)Sr(0.27)MnO(3) particles of size range 20-100 nm showed saturation magnetization around 38 emu/g at 20 kOe and a T(C) value of 45 degrees C. Aqueous suspension of these nanoparticles was prepared using a polymer, acrypol 934, and the biocompatibility of the suspension was examined using HeLa cells. A good heating ability of the magnetic suspension was obtained in the presence of AC magnetic field, and it was found to increase with the amplitude of field. The suspension having concentration of 0.66 mg/mL (e.g., 0.66 mg of nanoparticles with acropyl per milliliter of culture media) was observed to be biocompatible even after 96 h of treatment, as estimated by sulforhodamine B and trypan blue dye exclusion assays. Further, the treatment with the aforementioned concentration did not alter the microtubule cytoskeleton or the nucleus of the cells. However, the bare particles (concentration of 0.66 mg of nanoparticles per milliliter of culture media, but without acropyl) decreased the viability of cell significantly. Our in vitro studies suggest that the suspension (concentration of 0.66 mg/mL) may further be analyzed for in vivo studies.


Assuntos
Compostos Férricos , Teste de Materiais , Nanopartículas , Sobrevivência Celular , Compostos Férricos/química , Células HeLa , Humanos , Hipertermia Induzida/métodos , Magnetismo , Imãs , Teste de Materiais/métodos , Neoplasias/terapia , Fatores de Tempo
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