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1.
Hum Reprod ; 37(7): 1423-1430, 2022 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-35640043

RESUMO

STUDY QUESTION: Is there a relation between specific Na+/K+ ATPase isoform expression and localization in human blastocysts and the developmental behavior of the embryo? SUMMARY ANSWER: Na+/K+ ATPase α1, ß1 and ß3 are the main isoforms expressed in human blastocysts and no association was found between the expression level of their respective mRNAs and the rate of blastocyst expansion. WHAT IS KNOWN ALREADY: In mouse embryos, Na+/K+ ATPase α1 and ß1 are expressed in the basolateral membrane of trophectoderm (TE) cells and are believed to be involved in blastocoel formation (cavitation). STUDY DESIGN, SIZE, DURATION: A total of 20 surplus embryos from 11 patients who underwent IVF and embryo transfer at a university hospital between 2009 and 2018 were analyzed. PARTICIPANTS/MATERIALS, SETTING, METHODS: After freezing and thawing Day 5 human blastocysts, their developmental behavior was observed for 24 h using time-lapse imaging, and the expression of Na+/K+ ATPase isoforms was examined using quantitative RT-PCR (RT-qPCR). The expressed isoforms were then localized in blastocysts using fluorescent immunostaining. MAIN RESULTS AND THE ROLE OF CHANCE: RT-qPCR results demonstrated the expression of Na+/K+ ATPase α1, ß1 and ß3 isoforms in human blastocysts. Isoforms α1 and ß3 were localized to the basolateral membrane of TE cells, and ß1 was localized between TE cells. A high level of ß3 mRNA expression correlated with easier hatching (P = 0.0261). LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: The expression of mRNA and the localization of proteins of interest were verified, but we have not been able to perform functional analysis. WIDER IMPLICATIONS OF THE FINDINGS: Of the various Na+/K+ ATPase isoforms, expression levels of the α1, ß1 and ß3 mRNAs were clearly higher than other isoforms in human blastocysts. Since α1 and ß3 were localized to the basolateral membrane via fluorescent immunostaining, we believe that these subunits contribute to the dilation of the blastocoel. The ß1 isoform is localized between TE cells and may be involved in tight junction formation, as previously reported in mouse embryos. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the JSPS KAKENHI (https://www.jsps.go.jp/english/index.html), grant number 17K11215. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors have no conflicts of interest.


Assuntos
Blastocisto , Embrião de Mamíferos , Animais , Blastocisto/metabolismo , Membrana Celular/metabolismo , Embrião de Mamíferos/metabolismo , Humanos , Camundongos , RNA Mensageiro/metabolismo , ATPase Trocadora de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/metabolismo
2.
Lupus ; 20(8): 871-5, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21415254

RESUMO

Hemophagocytic syndrome (HPS) is a serious complication of systemic lupus erythematosus (SLE). A 15-year-old female with lupus-nephritis developed HPS. Bone marrow study showed florid thrombophagocytosis. There was no associated infection. High-dose methylprednisolone therapy ameliorated HPS. However, atrial fibrillation (Af) repeated after the infusion and required direct-current cardioversion. No underlying diseases were found in the heart and endocrine system. Chest roentgenogram and echocardiography were normal. Electrocardiogram showed slightly prolonged PR interval in sinus rhythm. Af occurred at high circulating levels of interferon-γ and interleukin (IL)-10, but not IL-6, IL-2, tumor necrosis factor-α, C-reactive protein or catecholamines. This is the first observation that high-dose corticosteroid induced Af in a case of lupus-HPS. Af is unusual in SLE children without cardiac disease, while conduction defect occurs associated with lupus-myocarditis. Lupus-HPS may be an aggressive SLE subset with cardiac involvement. High-dose corticosteroid infusion controls lupus activity, but could disclose the cardiac stress in lupus-HPS patients.


Assuntos
Fibrilação Atrial/induzido quimicamente , Glucocorticoides , Lúpus Eritematoso Sistêmico , Linfo-Histiocitose Hemofagocítica , Metilprednisolona , Adolescente , Medula Óssea/patologia , Proteína C-Reativa/metabolismo , Catecolaminas/sangue , Citocinas/sangue , Feminino , Glucocorticoides/efeitos adversos , Glucocorticoides/uso terapêutico , Humanos , Lúpus Eritematoso Sistêmico/complicações , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/etiologia , Metilprednisolona/efeitos adversos , Metilprednisolona/uso terapêutico
3.
Phys Rev Lett ; 90(16): 167403, 2003 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-12732007

RESUMO

Reversible valence tautomeric conversion induced by a single-shot laser pulse (8 ns duration) with a photon excitation energy of 2.38 eV has been observed in Na0.36Co1.32Fe(CN)(6).5.6H(2)O. A photoswitching process with accompanying magnetization and color changes was successfully achieved within the pulse duration at high temperature (above 200 K) in a thermal hysteresis loop. This unusual photoeffect originates from an optical charge transfer between Fe and Co atoms and evolves due to a cooperative interaction among the local photoexcited sites.

4.
Anal Chem ; 74(7): 1578-83, 2002 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-12033247

RESUMO

Conductive boron-doped diamond thin-film electrodes were used for the electrochemical detection of selected N-methylcarbamate pesticides (carbaryl, carbofuran, methyl 2-benzimidazolecarbamate, bendiocarb) after liquid chromatographic separation. Two kinds of detection methods were adopted in this study. In the first method, a direct detection of underivatized pesticides was carried out at an operating potential of 1.45 V versus Ag/AgCl, which resulted in the detection limits of 5-20 ng/mL (or 5-20 ppb) with S/N = 2 due to the low background current and wide potential window of the diamond electrode. In the second method, the detection limits were improved by subjecting the pesticide samples to alkaline hydrolysis in a separate step prior to injection. The phenolic derivatives obtained by alkaline hydrolysis oxidize at a relatively lower potential (0.9 V vs Ag/AgCl), which increases the sensitivity drastically. The advantage of the diamond electrode for the detection of phenolic derivatives is that it offers excellent stability in comparison to other electrodes. This method gives the detection limits of 0.6-1 ng/mL (or 0.6-1 ppb), which are well below the maximum residue levels allowed for carbaryl, carbofuran, and bendiocarb. While the lowest detection limits (LOD) obtained by the direct detection of pesticides are comparable to the those reported by the well-established HPLC-fluorescence, the LODs of the alkaline hydrolysis method are found to be even lower than the reported limits. On-line reactivation of the diamond electrode surface was shown to be possible by an anodic treatment of the electrode at approximately 3 V for 30 min in case of electrode fouling, which may occur after a prolonged use. Such a treatment damages the glassy carbon (GC) and metal electrodes, while the diamond electrode remains stable. These results suggest that the diamond electrode is superior to the other previously used electrodes such as GC and Kelgraf type for highly sensitive and stable detection of carbamate pesticides.


Assuntos
Carbamatos , Inseticidas/análise , Praguicidas/análise , Diamante , Eletroquímica , Eletrodos/normas , Sensibilidade e Especificidade
5.
Analyst ; 127(12): 1572-5, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12537361

RESUMO

Highly boron-doped diamond microfiber electrodes (BDDMF) were fabricated and characterized by the use of Scanning Electron Microscopy (SEM), Raman spectroscopy, and cyclic voltammetry. Amperometric detection of dopamine (DA), a neurotransmitter was achieved at pH 7.0, using BDDMF electrodes. The interferences from ascorbic acid (AA) and DOPAC were efficiently eliminated by using overoxidized polypyrrole-modified BDDMF electrodes, which also increased the sensitivity for the detection of dopamine. The limit of detection (S/N = 3) for dopamine was 0.1 nM, which is one order lower than that observed for carbon microfiber electrodes (CMFE), and the linear dynamic range was obtained from 0.5 nM to 100 microM (r2 = 0.997). The amperometric response for 0.5 nM dopamine has shown high stability with an RSD of 5.4% (n = 5). Highly reproducible results were obtained with an RSD of 6.2% for 10 measurements of 1 nM DA taken during 10 h and also remained the same, during measurements for 7 days, with no variation in efficiency for rejection of AA and DOPAC.


Assuntos
Cardiotônicos/análise , Dopamina/análise , Diamante , Eletroquímica/métodos , Microeletrodos , Sensibilidade e Especificidade
6.
J Am Chem Soc ; 123(47): 11644-50, 2001 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-11716720

RESUMO

The magnetic properties of the spin-crossover compounds, [Fe(qsal)2]NCSe-MeOH (1) and [Fe(qsal)2]NCSe-CH2Cl2 (2), have been measured. We have discovered that both compounds 1 and 2 exhibit a wide thermal hysteresis loop of 140 K (T(1/2) upward arrow = 352 K and T(1/2) downward arrow = 212 K) and 180 K (T(1/2) upward arrow = 392 K and T(1/2) downward arrow = 212 K), respectively, in the first cycle. Thermogravimetric analysis shows that solvent molecules escape from compounds 1 and 2 around 340 and 395 K, respectively. This means that the hysteresis loops observed for the first cycle are only apparent ones. Following the first loop, they show a two-step spin-crossover in warming mode. The so-called "step 1" and "step 2" are centered around T(1/2(S1)) upward arrow = 215 K and T(1/2(S2)) upward arrow = 282 K, respectively. On the other hand, a one-step spin-crossover occurs at T(1/2) downward arrow = 212 K in cooling mode. The hysteresis widths can be estimated to be 3 K (step 1) and 70 K (step 2), assuming that the widths in steps 1 and 2 are defined as the differences between T(1/2(S1)) upward arrow and T(1/2) downward arrow, and T(1/2(S2)) upward arrow and T(1/2) downward arrow, respectively. The hysteresis width of 70 K in step 2 is one of the widest values reported so far for spin-crossover complexes. It is thought that the cooperativity operating in the complexes arises mainly from the intermolecular pi interactions between quinoline and phenyl rings. Using a previously reported model, we are able to simulate the hysteresis loop with a two-step spin-crossover in warming mode and a one-step transition in cooling mode.

7.
Environ Sci Technol ; 35(11): 2365-8, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11414046

RESUMO

The photocatalytic degradation of bisphenol A (BPA), a representative endocrine disruptor, was carried out in TiO2 aqueous suspension. The main purposes were to confirm the total mineralization of BPA and to evaluate the estrogenic activity in the treated water during the photocatalytic reaction. An initial BPA concentration of 175 microM in water was totally degraded to carbon dioxide by TiO2-photocatalyzed reactions under UV irradiation of 10 mW cm-2 for 20 h. Four HPLC peaks indicating intermediate products appeared in chromatograms monitored at 275 nm, but the heights relative to that of the initial BPA were very low, at most 0.04 in the time period 5-10 h after the start of UV irradiation. All of the peaks finally disappeared after 20 h. For the treated water, the transcriptional estrogenic activity in response to human estrogen receptor in a yeast hybrid assay decreased drastically to less than 1% of the initial BPA's activity within 4 h. On the basis of these results, we conclude that TiO2 photocatalysis could be a useful technology for the purification of water containing BPA without generating any serious secondary pollution.


Assuntos
Estrogênios não Esteroides/efeitos adversos , Estrogênios não Esteroides/química , Fenóis/efeitos adversos , Fenóis/química , Fármacos Fotossensibilizantes/química , Receptores de Estrogênio/efeitos dos fármacos , Titânio/química , Poluentes Químicos da Água/análise , Compostos Benzidrílicos , Bioensaio , Dióxido de Carbono/química , Catálise , Cromatografia Líquida de Alta Pressão , Humanos , Fotoquímica
9.
Anal Chem ; 73(3): 514-9, 2001 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11217755

RESUMO

Boron-doped diamond (BDD) electrodes were used to examine L-cysteine (CySH) oxidation in alkaline media. The results of the voltammetric and polarization measurements showed that at BDD electrodes the overall CySH oxidation reaction is controlled by the initial electrochemical step, i.e., the oxidation of the CyS- electroactive species. The same conclusion was supported by the results of a study of pH effects. Conversely, at glassy carbon (GC) electrodes, the same reaction is controlled by the desorption of the reaction products. These results account for the poor response for CySH determination at GC compared to BDD. It was found that BDD exhibits excellent behavior for CySH determination, clearly outperforming GC. The results demonstrate that measurement of the peak current for CySH oxidation can be used as a basis for simple method for determining CySH in the micromolar concentration range by the use of BDD electrodes.


Assuntos
Cisteína/análise , Eletroquímica/métodos , Eletrodos , Diamante , Análise de Injeção de Fluxo
10.
J Biomed Mater Res ; 58(1): 97-101, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11153004

RESUMO

TiO(2) photocatalysts were successfully coated on silicone catheters or medical tubes by pretreatment of the silicone surface with a sulfuric acid solution (5 M) for 3 h. The TiO(2) film adhered to the silicone substrate strongly against tensile and bending stresses. On the TiO(2)-coated silicone-catheters under UV illumination, both the bleaching of methylene blue dye and the photocatalytic bactericidal effect on Escherichia coli (E. coli) cells were confirmed. Thus, this type of catheter can be sterilized and cleaned simply by irradiation with low-intensity UV light and can, therefore, be useful in the protection from catheter-related bacterial infections.


Assuntos
Materiais Revestidos Biocompatíveis/química , Contaminação de Equipamentos/prevenção & controle , Controle de Infecções/métodos , Silicones/química , Esterilização/métodos , Titânio/química , Raios Ultravioleta , Materiais Revestidos Biocompatíveis/efeitos da radiação , Desenho de Equipamento , Escherichia coli/efeitos da radiação , Teste de Materiais , Azul de Metileno/efeitos da radiação , Microscopia Eletrônica de Varredura , Oxirredução , Fotoquímica , Maleabilidade , Espécies Reativas de Oxigênio , Ácidos Sulfúricos/farmacologia , Resistência à Tração , Titânio/efeitos da radiação
11.
J Clin Laser Med Surg ; 19(6): 315-8, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11776449

RESUMO

OBJECTIVE: The purpose of the present study was to evaluate the preventive effect of pulsed Nd:YAG laser irradiation with 38% diamine silver fluoride [Ag(NH3)2F] solution for the fracture of endodontically treated teeth in vitro. BACKGROUND DATA: There have been no reports on the preventive effect of tooth fracture using Nd:YAG laser with Ag(NH3)2F solution. MATERIALS AND METHODS: Twenty-eight human extracted teeth were used in this study. The teeth were randomly classified into four groups: control group, where tooth surfaces were not submitted to any treatment; group 1, where tooth surfaces were coated with 38% Ag(NH3)2F solution; group 2, where tooth surfaces were coated with Ag(NH3)2F solution and irradiated by pulsed Nd:YAG laser for 2 sec; and group 3, where tooth surfaces were coated with Ag(NH3)2F solution and irradiated by pulsed Nd:YAG laser for 10 sec. After preparation, shear tests were performed and the maximum load for the fracture was measured. Results were analyzed using the Scheffe test, and difference at p < 0.05 was considered significant. RESULTS: The failure load for group 2 (mean, 182.5 kg) had the highest mean value and differed significantly from those for the control group (mean, 146.3 kg) and group 1 (mean, 147.1 kg; p < 0.05). The failure loads for groups 1 and 3 (mean, 150.0 kg) did not differ significantly from that for the control group (p > 0.05). CONCLUSION: The results show that the application of 38% Ag(NH3)2F solution followed by pulsed Nd:YAG laser irradiation for 2 sec is useful for prevention of tooth fracture at endodontically treated teeth.


Assuntos
Terapia com Luz de Baixa Intensidade/métodos , Compostos de Amônio Quaternário/farmacologia , Fraturas dos Dentes/prevenção & controle , Fluoretos Tópicos , Humanos , Dente Molar , Neodímio , Probabilidade , Distribuição Aleatória , Valores de Referência , Sensibilidade e Especificidade , Compostos de Prata , Soluções
12.
J Antibiot (Tokyo) ; 54(11): 934-47, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11827036

RESUMO

Novel anti-Helicobacter pylori antibiotics, pyloricidins A, A1, A2, B, C and D were isolated from Bacillus sp. HC-70 and Bacillus sp. HC-72 by column chromatographies using adsorption and ion exchange resins. Their structures have been elucidated based on spectroscopic and degradation studies and shown to be peptide-like compounds. These compounds contained two unusual amino acids, viz., 5-amino-2,3,4,6-tetrahydroxyhexanoic acid and 3-amino-3-phenylpropionic acid (beta-phenylalanine). The structure-activity relationship studies suggested that 3-(5-amino-2,3,4,6-tetrahydroxyhexanoyl)amino-3-phenylpropionic acid moiety was essential for anti-H. pylori activity.


Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bacillus/química , Peptídeos , Aminoácidos/análise , Antibacterianos/química , Cristalografia por Raios X , Fermentação , Cromatografia Gasosa-Espectrometria de Massas , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Rotação Ocular , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Relação Estrutura-Atividade
13.
Inorg Chem ; 38(20): 4405-4412, 1999 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-11671150

RESUMO

Two kinds of cobalt-iron cyanides (Rb(0.66)Co(1.25)[Fe(CN)(6)].4.3H(2)O and Co(1.5)[Fe(CN)(6)].6H(2)O) with different electronic structures have been investigated to understand the photoinduced long-range magnetic ordering. Rb(0.66)Co(1.25)[Fe(CN)(6)].4.3H(2)O produces a photomagnetic effect, whereas Co(1.5)[Fe(CN)(6)].6H(2)O does not respond to light. FT-IR and Mössbauer studies revealed that their oxidation states are expressed as Rb(0.66)Co(III)(0.84)Co(II)(0.41)[Fe(II)(CN)(6)] and Co(II)(1.5)[Fe(III)(CN)(6)], respectively. The difference in the oxidation states of the metal atoms in these two compounds has been explained by the Co coordination with H(2)O or CN ligands. In the case of Rb(0.66)Co(1.25)[Fe(CN)(6)].4.3H(2)O, more CN ligands are involved in coordination than expected in the case of Co(1.5)[Fe(CN)(6)].6H(2)O. A charge-transfer (CT) band from Fe(II) to Co(III) is observed at around 550 nm for Rb(0.66)Co(1.25)[Fe(CN)(6)].4.3H(2)O. The magnetism of Rb(0.66)Co(1.25)[Fe(CN)(6)].4.3H(2)O changed from paramagnetic to ferrimagnetic due to the CT from Fe(II) to Co(III) when illuminated at low temperature. The Curie temperature after illumination was 22 K. This metastable state was stable for more than several days at 5 K. The metastable state was restored back to its original one when the sample was heated to 120 K. It is considered that the interconversion proceeded via a pronounced domain formation.

14.
FEBS Lett ; 407(1): 47-50, 1997 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-9141479

RESUMO

We have determined the three dimensional structure of the complex of human cathepsin L and E-64, an irreversible inhibitor of cysteine proteases, at 2.5 A resolution. The overall structure was similar to that of other known cysteine proteases and apparently identical to the mature region of procathepsin L. The electron density for E-64 is clearly visible except for the guanidinobutane moiety. From comparison of the active sites of cathepsin L and B, we found the following: (1) The S' subsites of cathepsin L and B are totally different because of the 'occluding loop' lying on the end of the S' subsites of cathepsin B. (2) The S2 pocket of cathepsin L is shallow and narrow compared to that of cathepsin B. (3) The S3 subsites of the two enzymes are more similar than the other subsites, but cathepsin L may accommodate a more bulky group at this site. Knowledge of the active site structure of cathepsin L should be helpful for the structure-based design of potent and specific inhibitors which are of therapeutic importance.


Assuntos
Catepsinas/química , Cisteína Endopeptidases/química , Inibidores de Cisteína Proteinase/química , Endopeptidases , Leucina/análogos & derivados , Catepsina L , Catepsinas/antagonistas & inibidores , Catepsinas/genética , Cristalografia por Raios X , Cisteína Endopeptidases/genética , Humanos , Leucina/química , Modelos Moleculares , Proteínas Recombinantes/química
15.
Biochem Biophys Res Commun ; 228(3): 792-6, 1996 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-8941355

RESUMO

Human procathepsin L (25mg) was highly purified from the culture filtrate (4L) of mouse myeloma cells (Sp-HCL/HE14) transformed with human procathepsin L cDNA. The procathepsin L was almost completely converted to the mature form (18mg) under the acidic condition. Some properties of the mature cathepsin L were found to be different from those of the human liver-derived enzyme. In addition, we first produced crystals of mature human cathepsin L with E-64 using polyethylene glycol 6000 as the precipitant. The crystal was orthorhombic and belonged to the space group P2(1)2(1)2(1). The unit cell dimensions were: a = 49.8 A, b = 103.9 A, c = 47.8 A. The cell volume (2.47 x 10(5) A3) and calculated molecular mass (24.6 kDa) gave a volume/mass ratio of 2.5 A3/Da, which indicates that the asymmetric unit contains one molecule of enzyme.


Assuntos
Catepsinas/química , Endopeptidases , Precursores Enzimáticos/química , Animais , Catepsina L , Cristalização , Cristalografia por Raios X , Cisteína Endopeptidases , DNA Complementar , Humanos , Camundongos , Proteínas Recombinantes/química , Células Tumorais Cultivadas
16.
Science ; 272(5262): 704-5, 1996 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-8662564

RESUMO

Photoinduced magnetization was observed in a Prussian blue analog, K0.2Co1.4- [Fe(CN)6]·6.9H2O. An increase in the critical temperature from 16 to 19 kelvin was observed as a result of red light illumination. Moreover, the magnetization in the ferrimagnetic region below 16 kelvin was substantially increased after illumination and could be restored almost to its original level by thermal treatment. These effects are thought to be caused by an internal photochemical redox reaction. Furthermore, blue light illumination could be used to partly remove the enhancement of the magnetization. Such control over magnetic properties by optical stimuli may have application in magneto-optical devices.

17.
Br J Cancer ; 70(6): 1107-11, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7981061

RESUMO

A photoexcited titanium dioxide surface has a strong ability to decompose water into hydrogen and oxygen. We have studied this effect in order to use it to kill cancer cells in vitro and in vivo. A distinct cell killing effect was observed on cultured T-24 human bladder cancer cells treated with titanium dioxide particles and 300-400 nm UV light irradiation. Titanium dioxide plus UV light also dramatically suppressed the tumour growth of T-24 cells that were implanted in nude mice. Cells cultured on the titanium dioxide electrode were also killed under UV irradiation when the electrode was anodically polarised, suggesting that photogenerated holes are involved in the cell killing. The cell killing effect caused by titanium dioxide particles plus UV light irradiation was significantly hampered in the presence of L-cysteine and catalase, scavengers of hydroxyl radicals and hydrogen peroxide respectively. Transmission electron microscopic observations showed the titanium dioxide particles to be distributed on the cell surface and inside the cells. These results suggest that titanium dioxide particles under UV light irradiation produced photogenerated holes on the surface yielding hydroxyl radicals and hydrogen peroxide inside or outside the cells and the cells were then killed by the action of these highly oxidising molecules. The possible application of photoexcited titanium dioxide particles to cancer treatment as a new anti-cancer modality is discussed.


Assuntos
Titânio/uso terapêutico , Neoplasias da Bexiga Urinária/tratamento farmacológico , Catalase/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Cisteína/farmacologia , Humanos , Técnicas In Vitro , Microscopia Eletrônica , Titânio/metabolismo , Titânio/efeitos da radiação , Células Tumorais Cultivadas , Raios Ultravioleta
18.
Biochim Biophys Acta ; 1201(2): 259-65, 1994 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-7947940

RESUMO

We reported that malignant cells are inactivated by photo-excited TiO2 particles (Cai, R.-X., et al. (1992) Cancer Res. 52, 2346-2348). In the present study, the process of cell death of a human bladder cell line T24 with the irradiated TiO2 was investigated by monitoring the time course change in intracellular calcium concentration ([Ca2+]i) under UV irradiation using calcium fluorescence indicator, fura-2. In the presence of photo-excited TiO2 particles (100 micrograms/ml), [Ca2+]i showed a rapid two-step increase; while in the absence of TiO2, it exhibited only a slight and monotonous increase or maintained a constant level. The rapid elevation of [Ca2+]i in the presence of photo-excited TiO2 particles was caused by the influx of extracellular Ca2+ through the plasma membrane and cell death occurred only after the second rapid elevation of [Ca2+]i. These results suggested that the cell membrane permeability to Ca2+ was promoted prior to cell death.


Assuntos
Cálcio/análise , Titânio/farmacologia , Permeabilidade da Membrana Celular , Sobrevivência Celular , Etídio , Fura-2 , Humanos , Fatores de Tempo , Titânio/efeitos da radiação , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/ultraestrutura , Raios Ultravioleta
20.
Cancer Res ; 52(8): 2346-8, 1992 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-1559237

RESUMO

Photoexcited TiO2 particles can drive various chemical reactions due to their strong oxidizing and reducing ability. To investigate the possible use of this effect for cancer treatment, the antitumor activity of photoexcited TiO2 particles was studied in vitro and in vivo. HeLa cells cultured in vitro were completely killed in the presence of TiO2 (50 micrograms/ml) with 10-min UV irradiation by a 500-W-Hg lamp. In contrast, very little cell death was observed from TiO2 treatment without UV irradiation. Photoexcited TiO2 particles also significantly suppressed the growth of HeLa cells implanted in nude mice, compared with those receiving TiO2 alone or UV irradiation alone. The cell death caused by photoexcited TiO2 particles was significantly protected in the presence of L-tryptophan and catalase. These molecules are quenchers of hydroxyl radicals and scavengers of hydrogen peroxide, respectively, suggesting that the cells were killed by the OH. and H2O2 produced from photoexcited TiO2 particles.


Assuntos
Células HeLa/efeitos da radiação , Titânio/farmacologia , Animais , Sobrevivência Celular , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Hidrogênio/metabolismo , Peróxido de Hidrogênio/metabolismo , Camundongos , Camundongos Nus , Terapia Ultravioleta
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