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1.
Nature ; 576(7785): 85-90, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31723266

RESUMO

Thermoelectric materials transform a thermal gradient into electricity. The efficiency of this process relies on three material-dependent parameters: the Seebeck coefficient, the electrical resistivity and the thermal conductivity, summarized in the thermoelectric figure of merit. A large figure of merit is beneficial for potential applications such as thermoelectric generators. Here we report the thermal and electronic properties of thin-film Heusler alloys based on Fe2V0.8W0.2Al prepared by magnetron sputtering. Density functional theory calculations suggest that the thin films are metastable states, and measurements of the power factor-the ratio of the Seebeck coefficient squared divided by the electrical resistivity-suggest a high intrinsic figure of merit for these thin films. This may arise from a large differential density of states at the Fermi level and a Weyl-like electron dispersion close to the Fermi level, which indicates a high mobility of charge carriers owing to linear crossing in the electronic bands.

2.
J Investig Allergol Clin Immunol ; 22(2): 116-25, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22533234

RESUMO

BACKGROUND: The pathogenic mechanisms of atopic dermatitis (AD) and recurrent wheezing (RW) during infancy are not fully understood. OBJECTIVE: We evaluated immunological markers associated with AD and RW during infancy. METHODS: We followed a cohort (n = 314) from birth to 14 months of age. Some of the participants underwent a physical examination and blood test at 6 and 14 months of age. Univariate and multivariate logistic regression analysis and receiver operating characteristic curve analysis were performed to find which immunological markers could be risk factors for AD and RW. RESULTS: Of 16 immunological markers found in cord blood, only immunoglobulin (Ig) E was associated with AD at 6 months of age (adjusted OR [aOR], 1.607). None of the markers was associated with AD or RW at 14 months of age. Of 23 immunological markers at 6 months of age, total IgE (aOR, 1.018) and sensitization to egg white (aOR, 23.246) were associated with AD at 14 months of age. Phytohemagglutinin (PHA)-induced production of interleukin (IL) 4 from peripheral blood mononuclear cells (PBMCs) (aOR, 1.043) was associated with RW at 14 months of age. CONCLUSION: Cord blood IgE was a risk factor for AD at 6 months of age. Total IgE and sensitization to egg white at 6 months of age were risk factors for AD at 14 months of age. PHA-induced IL-4 production in PBMCs at 6 months of age was a risk factor for RW at 14 months of age.


Assuntos
Dermatite Atópica/etiologia , Dermatite Atópica/imunologia , Sons Respiratórios/etiologia , Sons Respiratórios/imunologia , Biomarcadores/sangue , Estudos de Coortes , Dermatite Atópica/sangue , Clara de Ovo , Feminino , Sangue Fetal/imunologia , Sangue Fetal/metabolismo , Seguimentos , Humanos , Imunoglobulina E/sangue , Lactente , Recém-Nascido , Interleucina-4/imunologia , Leucócitos Mononucleares/imunologia , Masculino , Análise Multivariada , Fito-Hemaglutininas/imunologia , Análise de Regressão , Fatores de Risco
3.
Artigo em Inglês | MEDLINE | ID: mdl-18361105

RESUMO

Protein-losing enteropathy (PLE), the manifestation of a diverse set of disorders, is characterized by excessive loss of plasma proteins into the affected portions of the gastrointestinal tract, and this results in hypoalbuminemia. A 5-month-old breastfed boy presented severe PLE with hypogammaglobulinemia, hypocalcemia, and hypomagnesemia induced by an egg allergy. He developed hypocalcemic convulsions. The diagnosis of PLE was confirmed by elevated fecal alpha1-antitrypsin clearance and a positive finding on a protein-losing scintigram. His allergy to egg delivered through maternal milk was confirmed as the cause of PLE, since the mother's elimination of egg from her diet improved his condition and maternal egg challenge provoked symptoms of diarrhea, vomiting, and elevated alpha1-antitrypsin clearance. At the time of writing, he is 22 months old and has experienced no further episodes after the elimination of egg-containing food.


Assuntos
Hipersensibilidade a Ovo/complicações , Enteropatias Perdedoras de Proteínas/etiologia , Aleitamento Materno , Humanos , Imunoglobulina E/sangue , Lactente , Masculino
4.
Clin Exp Immunol ; 140(3): 520-3, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15932514

RESUMO

X-linked agammaglobulinaemia (XLA) is an inherited immunodeficiency that is caused by a block in early B-cell differentiation. Whereas early B precursors in the bone marrow are present in substantial numbers, XLA-affected individuals have dramatically reduced numbers of circulating mature B cells, plasma cells and immunoglobulins of all isotypes. We report on a Japanese family with 3 XLA patients, in whom the serum immunoglobulin levels and number of B cells showed a significant difference among them in spite of harbouring the same splice donor site mutation in the BTK gene. We developed concise method for detection of this mutation, which is helpful for discovering the carrier. Patient 2 showed a significant serum immunoglobulin levels of all isotypes, including allergen-specific IgE. Expression of a normal and truncated size BTK gene was detected in patient 2's peripheral blood mononuclear cells (PBMCs). Expression of BTK protein was also detected in some B cells. These results suggest that the leaky phenotype in patient 2 was caused in part by the expression of a normal BTK gene transcript. The increased frequency of infection with age expanded the number of B cells with normal BTK gene expression and produced the serum immunoglobulin, including IgE.


Assuntos
Agamaglobulinemia/genética , Cromossomos Humanos X/genética , Ligação Genética/genética , Adulto , Tirosina Quinase da Agamaglobulinemia , Agamaglobulinemia/imunologia , Linfócitos B/imunologia , Criança , Pré-Escolar , Saúde da Família , Feminino , Expressão Gênica/genética , Humanos , Imunoglobulinas/sangue , Japão , Leucócitos Mononucleares/imunologia , Contagem de Linfócitos/métodos , Masculino , Mutação , Linhagem , Fenótipo , Proteínas Tirosina Quinases/genética
5.
Clin Genet ; 66(3): 236-8, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15324323

RESUMO

Epidermolysis bullosa simplex (EBS) is an autosomal-dominant inherited blistering skin disease characterized by intraepidermal blistering due to mechanical stress-induced degeneration of basal keratinocytes. EBS is caused by mutations in either keratin 5 or keratin 14, the major keratins expressed in the basal layer of the epidermis. We experienced a unique EBS-affected family. The proband had a heterozygous 1649delG mutation in the keratin 5 gene and had been reported as a case of de novo mutation, because the mutations were not detected in the parents' DNA from blood samples. However, the proband's younger sister was revealed to have the same disease at birth and we found the same mutation in her. We reinvestigated the familial segregation of the 1649delG mutation and it was shown that the mother's DNA from hair bulb and buccal cell samples had the 1649delG mutation heterozygously, but her DNA from blood samples did not. A careful check on the mother's history disclosed that she had migratory circinate pigmentation in her skin in childhood, which means maternal somatic and germline mosaicism. The demonstration of somatic and gonadal mosaicism in the keratin 5 gene is important for accurate genetic counselling of families with sporadic cases of EBS.


Assuntos
Epidermólise Bolhosa Simples/genética , Queratinas/genética , Mosaicismo , Mutação/genética , Sequência de Bases , Éxons/genética , Feminino , Mutação em Linhagem Germinativa/genética , Humanos , Recém-Nascido , Japão , Queratina-5 , Dados de Sequência Molecular , Análise de Sequência de DNA
6.
Oncol Rep ; 11(4): 785-9, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15010873

RESUMO

SART3 has been identified as a tumor antigen recognized by cytotoxic T-lymphocytes. Subcellular localization of SART3 is still controversial, although it has been studied extensively. In this study, we established an anti-SART3 monoclonal antibody (mAb) to analyze the subcellular localization of SART3 in tumor specimens. Immunohistochemical analysis demonstrated that SART3 was preferentially expressed in the nucleus of cancer cells. Flow cytometric analysis indicated that SART3 was not expressed on the cell surface of tumor cells, except for B-lineage cells. SART3 was detected on the cell surface of several B-lineage leukemic cells with different maturation stages, but not on normal peripheral blood B cells. These results suggest that heterotopically expressed SART3 is a tumor-associated antigen rather than a differentiation antigen on B-lineage cells.


Assuntos
Anticorpos Monoclonais/imunologia , Antígenos de Neoplasias/análise , Núcleo Celular/química , Leucemia de Células B/metabolismo , Proteínas de Ligação a RNA/análise , Animais , Anticorpos Monoclonais/isolamento & purificação , Antígenos de Neoplasias/imunologia , Antígenos de Neoplasias/metabolismo , Antígenos de Superfície/análise , Antígenos de Superfície/imunologia , Antígenos de Superfície/metabolismo , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Citometria de Fluxo , Humanos , Hibridomas , Imunoquímica , Leucemia de Células B/imunologia , Proteínas de Ligação a RNA/imunologia , Proteínas de Ligação a RNA/metabolismo
7.
Tissue Antigens ; 61(5): 352-61, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12753654

RESUMO

We previously demonstrated that CTL-directed epitopes derived from non-mutated self-antigens elicit a type-I allergy in the majority of healthy donors (HD) as did the presence of IgE and IgG reactive to these peptides in the sera of the donors. We investigated in this study whether Igs reactive to eight types of CTL-directed peptides were elevated in the sera of 40 patients with atopic dermatitis (AD). Total IgE levels in the sera of AD patients were significantly higher than those of HD, however, no significant differences between the AD patients and the HD were observed in either the serum levels or the positive rates of IgE reactive to seven of the eight peptides. Total IgG levels were not different from each other, however, IgG reactive to the two peptides with no sequence similarity to other species and one peptide that had similarity to DNA helicase II of enterobacteria were not detectable in the sera of the AD patients. Although IgG reactive to the remaining five peptides, which had sequence similarity to other species, were detectable in both the AD patients and the HD, ratios of peptide-specific IgG1/IgG2 were mostly lower in the AD patients than in the HD. These results indicate that IgG reactive to CTL-directed epitopes of self-antigens is either lacking or unbalanced in AD patients. This information may provide new insight into the immune-mechanisms of elevated auto-reactivity of AD patients.


Assuntos
Autoantígenos/imunologia , Dermatite Atópica/imunologia , Imunoglobulina G/imunologia , Fragmentos de Peptídeos/imunologia , Linfócitos T Citotóxicos/imunologia , ADP Ribose Transferases/imunologia , Adolescente , Adulto , Antígenos de Neoplasias/imunologia , Autoantígenos/sangue , Estudos de Casos e Controles , Criança , Ciclofilinas/imunologia , Proteínas de Ligação a DNA/imunologia , Dermatite Atópica/sangue , Epitopos , Feminino , Humanos , Imunoglobulina E/classificação , Imunoglobulina E/imunologia , Imunoglobulina G/classificação , Masculino , Proteínas de Membrana/imunologia , Proteínas de Neoplasias/imunologia , Peptidilprolil Isomerase , Proteínas de Ligação a RNA/imunologia
8.
Acta Anaesthesiol Scand ; 46(5): 592-8, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12027855

RESUMO

BACKGROUND: Although one lung ventilation (OLV) is commonly used, little is known about the modulation of the autonomic nervous system with OLV while under general anesthesia. As the frequency domain and time domain analyses are powerful analytic tools, we investigated their modulation during OLV. METHODS: Patients undergoing thoracic surgery were classified into two groups: those who did (group A, n=8) and those who did not (group N, n=8) receive atropine. After a double lumen tube was placed endotracheally, mechanical ventilation of both lungs (BLV) was established at 18 min(-1) while under isoflurane anesthesia. Electrocardiogram, systolic arterial pressure (SAP), and inspiratory flow (Finsp) were digitally recorded as follows: awake before anesthesia; BLV after anesthesia; BLV after intravenous 10 microg kg(-1) of atropine (group A) or not (group N); left OLV; and right OLV. Power spectral analyses of heart rate (HR) and SAP were computed by determining low-(LF, 0.04-0.15 Hz) and high-frequency (HF, 0.15-0.40 Hz) components, and impulse response analysis was executed among HR, SAP, and Finsp. Impulse responses were assessed by the maximum values in the time domain. RESULTS: In frequency domain analysis, atropine depressed LF and LF/HF but not HF in HR variability, while no difference was observed between right OLV and left OLV. The heart rate to SAP impulse response was maintained at a significantly higher level in group A than in group N (905+/-360 vs. 425+/-375 mmHg beats(-1)min(-1)) at right OLV. A significant difference was also observed between left and right OLV within group N. CONCLUSION: Impulse response analysis demonstrated that there is a greater effect on autonomic nervous system modulation during right OLV than in left OLV, which mainly results from a parasympathetic neural linkage origin.


Assuntos
Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Respiração Artificial , Adulto , Sistema Nervoso Autônomo/fisiologia , Interpretação Estatística de Dados , Lateralidade Funcional/fisiologia , Humanos , Masculino , Monitorização Intraoperatória , Testes de Função Respiratória , Procedimentos Cirúrgicos Torácicos
9.
Biochem Genet ; 39(3-4): 83-92, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11521509

RESUMO

Phenol oxidase in Drosophila melanogaster occurs as precursors designated prophenol oxidases A1 and A3. Crossing experiments between isozyme variants proved that prophenol oxidase in this species is a homodimer. Prophenol oxidases were partially purified using ammonium sulfate fractionation, phenyl Sepharose, and DEAE-cellulose column chromatography. The preparations were mixed, then dialyzed against buffer containing varying salt concentrations. The resulting prophenol oxidase was analyzed by gel electrophoresis. At 20 mM KCl or NaCl, two bands of phenol oxidase were observed, corresponding to the parental ones as monomer, whereas at 200 mM KCl or NaCl, three bands appeared in the gel, one being a dimer. The monomer-dimer reversibility of the Drosophila prophenol oxidase depends on the salt concentrations. The phenol oxidase activity remained unaffected within the KCl concentrations tested. Considering the ionic concentration of Drosophila hemolymph, these results indicate that prophenol oxidase exists as a dimer in vivo, and the higher-order structure of prophenol oxidase can be altered reversibly by ionic concentrations in vitro.


Assuntos
Catecol Oxidase/química , Catecol Oxidase/isolamento & purificação , Drosophila melanogaster/enzimologia , Precursores Enzimáticos/química , Precursores Enzimáticos/isolamento & purificação , Animais , Catecol Oxidase/metabolismo , Cromatografia em Gel , Troca Genética , Dimerização , Eletroforese em Gel de Poliacrilamida , Precursores Enzimáticos/metabolismo , Feminino , Masculino , Peso Molecular , Concentração Osmolar , Estrutura Quaternária de Proteína , Relação Estrutura-Atividade
10.
Nihon Koshu Eisei Zasshi ; 48(1): 28-37, 2001 Jan.
Artigo em Japonês | MEDLINE | ID: mdl-11235123

RESUMO

We decided to focus attention on healthy young people, and to conduct a survey of their diet, as well as their physical activity and health condition, so that we made diagnoses and also give instructions on each subject using a computer program to promote their health. We carried out this experiment using this method with 836 young female subjects in order to find out whether it can be applied as a useful health education approach. 1. According to the survey, when the subjects made efforts in making the instructions as convenient as possible, the percentage of subjects who could carry out advice even 4 months later was seen to be higher. 2. The advice for which a significantly high percentage of subjects said "want to improve their daily action" and could actually carry out and improve them, was as follows: they should eat vegetables, have a substantial breakfast, drink milk every day, refrain from too much salt, not go without meals, increase the frequency of eating seaweed, and refrain from snacks. 3. The two kinds of scores used to evaluate diets showed that assessment after nine months gave lower values than those obtained when this survey started. Using these two evaluating scores, changes in diets were divided into five patterns, and their relation to the question "whether they used the advice or not" was examined. As a result, the percentage showing favorable diet changes in subjects who "took advice" was showed to be significantly high. 4. Subjects who received advice on physical activity exhibited improvement in carrying out routine exercises as well as making their daily life more active. 5. With subjects who took advice on both diet and physical activity, the number who complained about fatigue was significantly reduced. Although it is difficult to improve diet and exercise habits, the results of the survey suggest that our approach should be useful for improving health.


Assuntos
Inquéritos sobre Dietas , Educação em Saúde/métodos , Adulto , Feminino , Humanos
11.
Hum Pathol ; 31(8): 955-60, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10987256

RESUMO

To investigate the possible role of mast cells (MC) in the angiogenic process in cutaneous melanoma, we examined tissue samples from 35 adult patients with primary malignant melanoma and compared with 20 intradermal benign nevi. MC were identified by anti-tryptase, microvessels by anti-CD34, and vascular endothelial growth factor (VEGF) expression by standard immunohistochemical methods. Tryptase-positive MC expressing VEGF were identified by double immunostaining. The numbers of MC and microvessels around the tumor were determined by the point counting method. MC density was significantly greater in melanoma compared with benign nevi (197.6 +/- 19.4 v 95.7 +/- 5.0/mm2, P < .001). Vascular density was also significantly higher in melanoma than in benign lesions (3.6-fold, P < .001). Double immunostaining showed the presence of VEGF in the cytoplasm of tryptase-positive peritumoral MC. The percentage of this MC-subtype was significantly higher in melanoma than in nevus tissues (71.9 +/- 2.4% v 30.6 +/- 2.5%, P < .001). A strong significant correlation was shown between the number of VEGF+ MC and microvessel density (r = .811, P < .001). MC count and VEGF+ MC count, as well as microvessel density were significantly higher in aggressive (metastasizing) melanomas (P < .001). Our results suggest that peritumoral accumulation of MC and the subsequent release of potent angiogenic factor such as VEGF may thus represent a tumor-host interaction that may favor progression of this tumor.


Assuntos
Melanoma/patologia , Neoplasias Cutâneas/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD34/análise , Quimases , Fatores de Crescimento Endotelial/biossíntese , Feminino , Humanos , Imuno-Histoquímica , Linfocinas/biossíntese , Masculino , Mastócitos/metabolismo , Mastócitos/patologia , Melanoma/metabolismo , Pessoa de Meia-Idade , Neovascularização Patológica/patologia , Serina Endopeptidases/análise , Neoplasias Cutâneas/metabolismo , Triptases , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
12.
J Oral Implantol ; 26(4): 250-6, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11831230

RESUMO

We have previously developed a computer-aided system for examination of the three-dimensional bone structure around implants and observed the bone changes in the healing period after implant placement. This paper describes the bone changes around hydroxyapatite (HA) and titanium (Ti) implants after abutment placement using histological and three-dimensional examinations. Twenty-four HA and Ti implants were embedded in the tibias of adult male New Zealand white rabbits. After 8 weeks, the abutment had passed through periosteum and was placed under the skin. Rabbits were sacrificed 4 and 8 weeks following abutment placement. In conclusion, histological examination showed that, at 4 weeks after abutment placement, bone resorption around the implant neck was seen in both HA and Ti implants, and at 8 weeks, excessive bone formation was seen around the implant neck. Three-dimensional bone examination showed that abutment placement may affect bone formation and cause additional bone hypertrophy in the bone marrow area.


Assuntos
Reabsorção Óssea/etiologia , Hiperostose/etiologia , Implantes Experimentais/efeitos adversos , Animais , Reabsorção Óssea/patologia , Gráficos por Computador , Dente Suporte/efeitos adversos , Durapatita/efeitos adversos , Hiperostose/patologia , Imageamento Tridimensional/métodos , Masculino , Coelhos , Tíbia/cirurgia , Fatores de Tempo , Titânio/efeitos adversos
13.
Dev Comp Immunol ; 23(7-8): 535-43, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10579382

RESUMO

The effect of null activity of phenoloxidase on the survival rate was investigated in mutants of Drosophila melanogaster. MoxGM95 and Dox-3KD95, structural genes for prophenoloxidase A1 and A3, were found in natural populations in the former Soviet Union, and affected the phenoloxidase activity in active A1 or A3, respectively. After linking the visible markers located on the second chromosome together with the variants, cross experiments were performed to make homozygote, rdo Dox-3KD95 pr C MoxGM95 wt. No double mutant had emerged. In the mutant, c MoxGM95 wt Pu2, the viability was greatly reduced. These results suggested that phenoloxidase and tyrosine-3-hydroxylase act as indispensable proteins to maintain life in Drosophila.


Assuntos
Drosophila melanogaster/enzimologia , Monofenol Mono-Oxigenase/fisiologia , Mutação , Animais , Cruzamentos Genéticos , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Feminino , Genes Letais , Masculino , Monofenol Mono-Oxigenase/genética
14.
Clin Oral Implants Res ; 10(3): 219-25, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10522182

RESUMO

Long-term support of dental implants requires adequate bone thickness in the area surrounding the implant. A three-dimensional examination, including calculations of percent bone-implant contact and percent bone volume, was conducted to clarify the bone structure around pure titanium (Ti) and dense hydroxyapatite (HA) implants. The implants were installed in the tibiae of rabbits, and the bone structure was examined after 2, 4, 6 and 8 weeks. The bone formation following implantation differed in the cortical bone and cancellous bone areas. In the cortical bone area, the percent bone-implant contact and percent bone volume were comparatively consistent for both Ti and HA implants during the observation period. In the cancellous bone area, both findings were influenced by the implantation period, and the chronological bone structure in the cancellous bone area also differed between Ti and HA implants. The percent bone-implant contact and percent bone volume in the Ti implant increased over 8 weeks, whereas the dense HA implant increased for the first 4 weeks and then decreased. The implant materials, Ti and HA, affected the bone remodeling in the cancellous bone area.


Assuntos
Durapatita , Implantes Experimentais , Osseointegração/fisiologia , Titânio , Análise de Variância , Animais , Densidade Óssea , Remodelação Óssea/fisiologia , Gráficos por Computador , Implantação Dentária Endóssea , Processamento de Imagem Assistida por Computador , Masculino , Coelhos , Tíbia
15.
Cancer Lett ; 140(1-2): 37-45, 1999 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-10403539

RESUMO

The inhibitory effects of the diacetylenic spiroketal enol ether epoxide AL-1 from Artemisia lactiflora on a variety of tumor promoter-induced biological responses such as oxidative stress as well as tumor promotion in ICR mouse skin were investigated. AL-1 inhibited TPA-induced intracellular peroxide formation in differentiated HL-60 cells, suggesting that this suppression might be attributable to the inhibition of O2- generation. In a double TPA application system in mouse skin, double pretreatments of AL-1 (810 nmol) significantly suppressed double TPA application-induced H2O2 generation. Pretreatment of AL-1 only before the second TPA treatment was sufficient to inhibit, while only with first treatment was not. From these results we concluded that AL-1 is a specific inhibitor of the activation phase in H2O2 production induced by double TPA treatments. In addition, AL-1 strongly inhibited tumor promoter-induced Epstein-Barr virus (EBV) activation in Raji cells (IC50 = 0.5 microM), which was comparable to or even stronger than that of curcumin, a well-known antioxidative chemopreventer from turmeric. In a two-stage carcinogenesis experiment with TPA (topical application at 1.6 nmol) and 7,12-dimethylbenz[a]anthracene (DMBA, at 0.19 micromol) in ICR mouse skin, topical application of AL-1 (at 160 nmol) significantly reduced tumor incidence, the numbers of tumors per mouse, and edema formation by 58% (P < 0.01 in t-test), 20% (P < 0.005 in chi2-test) and 42% (P < 0.01), respectively. These results together indicate that an inhibitor of O2 generation is an effective chemopreventer of mouse skin carcinogenesis by their antioxidative property.


Assuntos
Anticarcinógenos/uso terapêutico , Antineoplásicos Fitogênicos/uso terapêutico , Estresse Oxidativo/efeitos dos fármacos , Piranos/uso terapêutico , Neoplasias Cutâneas/prevenção & controle , Compostos de Espiro/uso terapêutico , 9,10-Dimetil-1,2-benzantraceno , Animais , Anticarcinógenos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Testes de Carcinogenicidade , Relação Dose-Resposta a Droga , Epiderme/efeitos dos fármacos , Epiderme/metabolismo , Feminino , Células HL-60 , Herpesvirus Humano 4/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Líquido Intracelular/efeitos dos fármacos , Líquido Intracelular/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Piranos/farmacologia , Neoplasias Cutâneas/induzido quimicamente , Compostos de Espiro/farmacologia , Acetato de Tetradecanoilforbol , Células Tumorais Cultivadas , Ativação Viral/efeitos dos fármacos
16.
J Biomater Sci Polym Ed ; 9(6): 543-59, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9659599

RESUMO

Polypropylene surfaces with a particular crystalline-amorphous microstructure have been demonstrated to reduce protein adsorption and platelet activation. Such blood-contacting properties may be affected by the crystalline-amorphous microstructure of the surfaces, although wettability such as dynamic contact angles and surface free energy components were almost constant, being independent from the variation in the microstructure. In order to clarify the mechanistic aspects on their blood-contacting properties, the physicochemical properties of the surfaces were evaluated for a series of compression-molded polypropylene sheets in terms of the work of adhesion and the structure of sorbed water. The work of adhesion of the compression-molded sheets increased with decreasing surface layer crystallinity, presumably due to macromolecular entanglement with a polymeric glue used. The work of adhesion involving macromolecular entanglement may occur between proteins and the surfaces. Thus, a decrease in the surface layer crystallinity is considered to cause an increase in the protein adsorption. The structure of water sorbed into the sheets changed--it was more gaseous (isolated) at the surfaces with a higher crystallinity. This suggests that the hydrophobic interaction via water molecules increased with surface layer crystallinity, resulting in increasing protein adsorption and denaturation. Thus, it is considered that both macromolecular entanglement and hydrophobic interaction are important on the mechanistic aspects of blood-contacting properties of polypropylene surfaces. In order to confirm this hypothesis, the evaluation of the physicochemical properties and blood-contacting properties was also performed on a series of uniaxially drawn polypropylene films. A decrease in the work of adhesion and the hydrophobic interaction at the surfaces was observed with increasing draw ratio, and the protein adsorption and platelet activation were effectively prevented with increasing draw ratio. This result supports our hypothesis. Therefore, it is concluded that the excellent blood-contacting properties of polypropylene surfaces can be achieved by reducing the macromolecular entanglement and the hydrophobic interaction with proteins.


Assuntos
Proteínas Sanguíneas/química , Sangue/metabolismo , Polipropilenos/química , Água/química , Adesividade , Adsorção , Animais , Fenômenos Biomecânicos , Plaquetas/química , Cristalização , Ativação Plaquetária , Desnaturação Proteica , Coelhos , Propriedades de Superfície
17.
Clin Oral Implants Res ; 8(1): 18-22, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9586452

RESUMO

Adequate bone quality and stress distribution to the bone are of decisive importance for implant success. The purpose of this in vitro study was to investigate the influence of bone quality on the stress distribution using 2 implant-bone mimicking models, simulating compact and cancellous bone quality. The resin model was made of an acrylic resin only simulating compact bone quality. The hybrid model was made of 2 kinds of materials, acrylic resin covered with a 1-mm layer of urethane to simulate cancellous bone quality. An implant was embedded in each model, and the abutment and suprastructures were connected to the implant. A strain gauge was placed perpendicular to the implant on the surface of the model and a small accelerometer was attached to the abutment. When an impact load was applied to the suprastructure, both strain and acceleration were measured. Both abutment acceleration and surface strain in the hybrid model decreased rapidly as time progressed when compared to the resin model. Abutment accelerations in the resin model were significantly lower than those in the hybrid model. In the hybrid model, the strain increased as the loading site was moved closer to the strain gauge. The influence of loading sites on strain in the resin model was greater than in the hybrid model. Therefore, the occlusal stress was distributed more widely in the hybrid model than in the resin model. This may indicate that occlusal stress in compact bone may have a tendency to concentrate in particular regions.


Assuntos
Processo Alveolar/fisiologia , Força de Mordida , Densidade Óssea , Análise do Estresse Dentário , Resinas Acrílicas , Análise de Variância , Elasticidade , Humanos , Modelos Estruturais , Uretana
18.
J Biomater Sci Polym Ed ; 8(11): 859-77, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9342652

RESUMO

Blood-contacting properties of polypropylene surfaces with different crystalline states at the surface layer were examined in terms of plasma protein adsorption and changes in cytoplasmic free Ca2+ levels in platelets. Though the wettability of polypropylene surfaces was almost constantly independent from the surface layer crystallinity and interlamellar spacing, an increase in adhesiveness was observed with decreasing surface layer crystallinity and interlamellar spacing. It is suggested that the surface properties of the sheets varied in relation to the crystalline-amorphous microstructure. Minimum magnitudes in albumin and fibrinogen adsorption were observed on the polypropylene surface with a particular surface layer crystallinity (c. 55 wt%). A decrease in interlamellar spacing resulted in enhancing albumin adsorption and diminishing fibrinogen adsorption. Transient phenomena in plasma protein adsorption were observed on their surfaces with a plasma concentration. It is considered that the polypropylene surface with a particular crystalline-amorphous microstructure reduces the denaturation of adsorbed proteins. An increase in cytoplasmic free Ca2+ levels in platelets was prevented at the polypropylene surface with a surface layer crystallinity of 55 wt%: the particular crystalline-amorphous microstructure of such apolar surfaces as polypropylenes acts to reduce platelet activation. Thus, it is concluded that the blood compatibility of polypropylene surfaces is greatly improved by controlling a crystalline-amorphous microstructure at the surface layer.


Assuntos
Materiais Biocompatíveis/química , Plaquetas/química , Cálcio/análise , Polipropilenos/química , Adesividade , Adsorção , Animais , Cristalização , Citoplasma/química , Fibrinogênio/química , Fura-2 , Adesividade Plaquetária , Coelhos , Albumina Sérica/química , Propriedades de Superfície
19.
J Oral Implantol ; 22(3-4): 232-5, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9524500

RESUMO

This paper describes rapid bone resorption in the peri-implantitis of HA implants based on both our clinical observations of and histological research on extracted dense hydroxyapatite (HA) implants. The surfaces of extracted HA implants were rough, although they were smooth at fixture placement. Plaque formed on the necks of the implants, whereas little plaque was seen on the bottoms. The plaque consisted of cocci and rods, including filamentous bacteria. Few spirochetes were observed. Although surrounding bone was formed rapidly around the HA implant, bone thickness gradually decreased compared with the titanium implant. These facts suggest that the rigid biointegration of HA with the thin surrounding bone--that is, the overstressing of the bone--causes rapid bone resorption rather than plaque accumulation on HA.


Assuntos
Perda do Osso Alveolar/etiologia , Implantes Dentários/efeitos adversos , Durapatita , Periodontite/etiologia , Adulto , Perda do Osso Alveolar/patologia , Placa Dentária/microbiologia , Planejamento de Prótese Dentária , Falha de Restauração Dentária , Feminino , Humanos , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade
20.
Biosci Biotechnol Biochem ; 59(10): 1913-20, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8534984

RESUMO

Previous studies have shown that selenium (Se) deficiency is associated with hematological abnormalities, which may result in an increased distribution of iron in various tissues. This report describes histological studies of the location of excess iron deposits in tissues. Male Wistar rats were fed a Torula yeast-based Se-deficient [Se(-)] or Se-adequate [Se(+); containing 0.1 mg Se/kg as sodium selenite] diet for 8 or 82 weeks. Excised tissues were embedded in either paraffin or epoxy resin. A dramatic increase was observed in iron deposition in the liver and kidneys of rats on the Se(-) diet. Prussian blue-stained sections under the light microscope showed iron deposits in the parenchymal cells and Kupffer cells of liver and in the proximal tubules of kidneys. The liver and kidneys of Se(-) rats had considerably altered morphology: lysosomes were enlarged and contained electron-dense areas. X-Ray microanalysis showed that the areas that corresponded to the lysosomes contained iron. No iron deposits were observed in sections of kidney and liver from rats fed the Se(+) diet. Thus, these studies identified subcellular sites of iron deposition in the liver and kidneys of Se(-) rats. These iron deposits may be an important factor in the pathogenesis of Se deficiency.


Assuntos
Ferro/metabolismo , Rim/metabolismo , Fígado/metabolismo , Selênio/deficiência , Animais , Peso Corporal , Modelos Animais de Doenças , Microanálise por Sonda Eletrônica , Rim/patologia , Fígado/patologia , Lisossomos , Masculino , Microscopia , Microscopia Eletrônica , Tamanho do Órgão , Ratos , Ratos Wistar
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