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1.
Mol Immunol ; 145: 50-58, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35290812

RESUMEN

Recently we identified the VRC01-like antibody DRVIA7(A7) from an HIV-1 B' subtype-infected individual (DRVI01) with broad neutralization activity, and almost all viruses from the individual were resistant to both VRC01 and A7 lineage antibodies. Here, we identified and characterized a panel of HIV-1 variants with resistance to VRC01 and A7 using site-directed mutagenesis and swapping amino acid fragments of gp120. Site-directed mutagenesis revealed that E279D/R282K/N460A/T464N of gp120 from DRVI01 produced VRC01-susceptible variants. Multiple mutations significantly increased the neutralization sensitivity to VRC01. Residues N464 located at the tip of the V5 loop were considered irrelevant to the neutralization of VRC01. For DRVI01-derived viruses, the single N464T change fully produced VRC01-resistant variants; conversely, a single T464N mutation generated VRC01-susceptible variants. Alanine scanning revealed that the N464 residue plays a vital role in binding with VRC01. Neutralizing assays against A7 lineage antibodies showed that DRVI01-derived viruses with multiple mutations could be neutralized by A7 lineage antibodies with different neutralizing breadths. Combining the changes in loops D and V5 produced variants that were totally sensitive variants to A7 lineage antibodies.


Asunto(s)
Infecciones por VIH , VIH-1 , Anticuerpos Monoclonales , Anticuerpos Neutralizantes , Anticuerpos Anti-VIH/genética , Proteína gp120 de Envoltorio del VIH/genética , Infecciones por VIH/genética , VIH-1/genética , Humanos , Mutación/genética
3.
Herz ; 46(3): 262-268, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32435839

RESUMEN

BACKGROUND: The optimal coronary revascularization strategy for patients with unprotected left main coronary artery (ULMCA) disease and left ventricular systolic dysfunction (LVSD) remains uncertain. The purpose of this study was to evaluate the clinical outcomes after percutaneous coronary intervention (PCI) with a drug-eluting stent (DES) versus coronary artery bypass grafting (CABG) in patients with ULMCA disease with or without LVSD. METHODS: A total of 984 patients with ULMCA disease who received a DES (n = 511) or underwent CABG (n = 473) were included in this study. We retrospectively analyzed the clinical parameters and outcomes of ULMCA disease patients with different left ventricular ejection fraction levels. RESULTS: There were no significant differences in major adverse cardiac and cerebral events, all-cause death, cardiac death, myocardial infarction, or stroke between the CABG and DES groups with or without LVSD. The rate of target vessel revascularization was significantly higher with DES compared with CABG in patients without LVSD; however, the difference was not significant between the mild LVSD and severe LVSD groups. CONCLUSION: For patients with ULMCA disease and LVSD, there was no significant difference between DES and CABG in terms of efficacy and safety. Treatment with DES was an acceptable alternative to CABG.


Asunto(s)
Enfermedad de la Arteria Coronaria , Stents Liberadores de Fármacos , Intervención Coronaria Percutánea , Enfermedad de la Arteria Coronaria/cirugía , Humanos , Estudios Retrospectivos , Volumen Sistólico , Resultado del Tratamiento , Función Ventricular Izquierda
4.
Eur J Med Chem ; 187: 111989, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31881456

RESUMEN

Lysine specific demethylase 1 (LSD1) plays an essential role in maintaining a balanced methylation status at histone tails. Overexpression of LSD1 has been involved in the development of a variety of human diseases, including cancers. Herein, on the basis of our previously developed LSD1 inhibitors, two series of new [1,2,3]triazolo[4,5-d]pyrimidine derivatives incorporating (thio)urea moiety were designed and evaluated for their LSD1 inhibitory abilities, leading to a novel chemical class of LSD1 inhibitors. Among them, compound 31 was found to moderately inhibit LSD1 activity, as well as increase the expression of H3K4me2 at the cellular level. This compound also showed good selectivity against MAO-A/-B, and a panel of kinases such as CDK and BTK. Besides, the MTT assay suggested that the selected compounds could inhibit the proliferation of LSD1-overexpressed cancer cells. Although this class of compounds only showed moderate anti-LSD1 activity in the micromolar range, this work presents a novel chemotype of LSD1 inhibitors with good enzyme selectivity as well as cellular LSD1 inhibitory activity, and could provide a useful template for the development of more potent LSD1 inhibitors for cancer treatment.


Asunto(s)
Antineoplásicos/farmacología , Inhibidores Enzimáticos/farmacología , Histona Demetilasas/antagonistas & inhibidores , Pirimidinas/farmacología , Triazoles/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Histona Demetilasas/metabolismo , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Pirimidinas/síntesis química , Pirimidinas/química , Relación Estructura-Actividad , Triazoles/síntesis química , Triazoles/química
5.
Quant Imaging Med Surg ; 9(6): 1126-1131, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31367567

RESUMEN

Hepatic granulomas caused by nontuberculous mycobacteria (NTM) are an uncommon, insidious, and indolent disease. Making an accurate diagnosis of a hepatic nontuberculous granuloma is challenging because of nonspecific clinical presentations and radiological appearances, especially in patients with a history of malignant tumors, as these lesions may mimic metastases and make a dilemma for decision-making in treatment. Herein, we report three cases of hepatic nontuberculous granulomas following operations for malignant tumors, including colon cancer, ovarian adenocarcinoma, and both rectal and renal carcinoma, respectively. Two patients presented with multiple hepatic lesions and the third had a solitary nodule in the liver. Computed tomography (CT) showed low attenuating nodules without early enhancement in the arterial phase but a slight peripheral enhancement in the portal venous phase after the intravenous administration of contrast agent. Magnetic resonance imaging (MRI) showed high signal intensity on T2-weighted image, rim enhancement in the venous phase and no contrast agent of Gd-EOB-DTPA uptake in the hepatobiliary phase. The biopsy was performed, and histopathological examinations revealed the chronic granulomas composed of epithelioid histiocytes, inflammatory cells, and Langhans giant cells. The results of nested polymerase chain reaction (PCR) were positive for NTM.

6.
Aging (Albany NY) ; 8(9): 1923-1939, 2016 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-27608489

RESUMEN

In this study, we assessed whether the down-regulation of Yes-associated protein (YAP) is involved in the pathogenesis of extracellular matrix (ECM) mechanical stress-induced Stanford type A aortic dissection (STAAD). Human aortic samples were obtained from heart transplantation donors as normal controls and from STAAD patients undergoing surgical replacement of the ascending aorta. Decreased maximum aortic wall velocity, ECM disorders, increased VSMC apoptosis, and YAP down-regulation were identified in STAAD samples. In a mouse model of STAAD, YAP was down-regulated over time during the development of ECM damage, and increased VSMC apoptosis was also observed. YAP knockdown induced VSMC apoptosis under static conditions in vitro, and the change in mechanical stress induced YAP down-regulation and VSMC apoptosis. This study provides evidence that YAP down-regulation caused by the disruption of mechanical stress is associated with the development of STAAD via the induction of apoptosis in aortic VSMCs. As STAAD is among the most elusive and life-threatening vascular diseases, better understanding of the molecular pathogenesis of STAAD is critical to improve clinical outcome.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Aorta/metabolismo , Aneurisma de la Aorta/metabolismo , Matriz Extracelular/metabolismo , Fosfoproteínas/metabolismo , Estrés Mecánico , Proteínas Adaptadoras Transductoras de Señales/genética , Adulto , Aorta/cirugía , Aneurisma de la Aorta/genética , Aneurisma de la Aorta/cirugía , Apoptosis/fisiología , Regulación hacia Abajo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Fosfoproteínas/genética , Factores de Transcripción , Proteínas Señalizadoras YAP
7.
Asian Pac J Cancer Prev ; 14(7): 4215-21, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23991979

RESUMEN

PURPOSES: Lung cancer is prevalent worldwide and improvements in timely and effective diagnosis are need. Pentraxin-3 as a novel serum marker for lung cancer (LC) has not been validated in large cohort studies. The aim of the study was to assess its clinical value in diagnosis and prognosis. METHODS: We analyzed serum PTX-3 levels in a total of 1,605 patients with LC, benign lung diseases and healthy controls, as well as 493 non- lung cancer patients including 12 different types of cancers. Preoperative and postoperative data were further assessed in patients undergoing LC resection. The diagnostic performance of PTX-3 for LC and early-stage LC was assessed using receiver operating characteristics (ROC) by comparing with serum carcinoembryonic antigen (CEA), cytokeratin 19 fragments (CYFRA 21-1). RESULTS: Levels of PTX-3 in serum were significantly higher in patients with LC than all controls. ROC curves showed the optimum diagnostic cutoff was 8.03ng/mL (AUC 0.823, [95%CI 0.789-0.856], sensitivity 72.8%, and specificity 77.3% in the test cohort; 0.802, [95%CI 0.762-0.843], sensitivity 69.7%, and specificity 76.4% in the validate cohort). Similar diagnostic performance of PTX-3 was observed for early-stage LC. PTX-3 decreased following surgical resection of LC and increased with tumor recurrence. Significantly elevated PTX-3 levels were also seen in patients with non-lung cancers. CONCLUSIONS: The present data revealed that PTX-3 was significantly increased in both tissue and serum samples in LC patients. PTX-3 is a valuable biomarker for LC and improved identification of patients with LC and early-stage LC from those with non-malignant lung diseases.


Asunto(s)
Biomarcadores de Tumor/sangre , Biomarcadores/análisis , Proteína C-Reactiva/metabolismo , Neoplasias Pulmonares/sangre , Pulmón/metabolismo , Recurrencia Local de Neoplasia/sangre , Lesiones Precancerosas/sangre , Componente Amiloide P Sérico/metabolismo , Adenocarcinoma/sangre , Adenocarcinoma/patología , Antígenos de Neoplasias/sangre , Antígeno Carcinoembrionario/sangre , Carcinoma de Células Escamosas/sangre , Carcinoma de Células Escamosas/patología , Estudios de Casos y Controles , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Queratina-19/sangre , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Lesiones Precancerosas/patología , Pronóstico , Curva ROC
8.
Chin Med J (Engl) ; 126(14): 2666-9, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23876893

RESUMEN

BACKGROUND: Patients with maxillary tumor often suffer from trismus after maxillectomy, which could turn out to be a permanent sequela without proper intervention. In this study, the efficacy of mouth opening exercises in preventing and treating trismus was observed in patients with maxillary tumor early after their operations. At the same time, radiotherapy as an influencing factor for the mouth opening exercises was evaluated. METHODS: In this study, 22 patients with maxillary oncology began their mouth opening exercises at an early stage (1-2 weeks) after maxillectomy. They were divided into two groups based on the principle of voluntariness: 11 patients in group 1 chose TheraBites as their instruments of mouth opening exercises, and the other 11 in group 2 chose stacked tongue depressors to help their exercises. All participants were trained to exercise 3-5 times a day, 30-40 oscillations at one time, with a 2-second pause at their maximum possible mouth open position. The maximal interincisor distances (MID) of patients were measured and recorded by a single investigator every week after the beginning of the mouth opening exercises. Medical information and the responses of patients were also recorded. Initial and final MIDs were calculated by SPSS 13.0. RESULTS: The changes of the mouth aperture every week during exercises in both groups were described in figures, and there were statistical increases in the final MIDs compared with the initial ones. However, no significant differences were achieved between groups 1 and 2 (P > 0.05). Radiotherapy seemed to have no negative impact on the mouth opening results during the exercises. CONCLUSION: Physical mouth opening exercises should be executed early after maxillectomy for the prevention and treatment of trismus, especially for those who had radiotherapy as part of antitumor treatments.


Asunto(s)
Maxilar/cirugía , Neoplasias Maxilares/cirugía , Boca/fisiopatología , Ejercicios de Estiramiento Muscular/métodos , Trismo/terapia , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ejercicios de Estiramiento Muscular/instrumentación , Trismo/etiología
9.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue ; 23(6): 333-6, 2011 Jun.
Artículo en Chino | MEDLINE | ID: mdl-21672379

RESUMEN

OBJECTIVE: To explore the influence of recombination granulocyte colony stimulating factor (rG-CSF) on mobilization and distribution of bone marrow stem cells (BMSCs) in blood and brain tissue, and its role in protecting brain in rats with cerebral ischemia. METHODS: One hundred and six Sprague-Dawley (SD) rats were divided into sham-operated group (n=10),model group (n=48), rG-CSF group (n=48) according to the method of random digital table, and rats in model and rG-CSF groups were divided into four subgroups: i.e. 2, 3, 7 and 14 days subgroups, with 12 rats in each subgroup. Middle cerebral artery occlusion (MCAO) model was reproduced with nylon thread. In rats of rG-CSF group rG-CSF (10 µg/kg) was administered by subcutaneous injection 3 days before and 2 days after operation respectively, once a day. Rats in sham-operated and model groups were administered with normal saline in the same volume, once a day. At the corresponding time after operation, general neural function score (GNFS) of rats was measured. Blood was collected through abdominal aorta, then white blood cell (WBC) and CD34+ cells in peripheral blood were counted. Brain pathologic changes were observed, and expression of CD34+ cells in rats brain tissue was determined by using immunohistochemical method. RESULTS: (1) GNFS was lower obviously in 2-day model group compared with that in sham-operated group, and then increased gradually. At 7 days and 14 days after operation, GNFS in rG-CSF group was higher significantly than that in model group (7 days: 11.86±0.69 vs. 10.53±0.76, 14 days: 13.38±0.52 vs. 12.38±0.52, both P<0.01). (2) WBC and CD34+ cells in peripheral blood in model group increased obviously, with the highest level appeared at 3 days and lowered at 7 days and 14 days. Increase of WBC and CD34+ cells in rats of rG-CSF group was more obvious than that of model group at each time point except CD34+ in 14 days group [WBC (×10(9)/L) 2 days: 11.75±1.76 vs. 8.07±1.27, 3 days: 13.07±1.70 vs. 10.88±1.78, 7 days: 8.63±1.36 vs. 5.58±1.57, 14 days: 6.98±0.98 vs. 4.87±0.92; CD34+ (cells/µl) 2 days: 8.83±2.14 vs. 3.17±0.75, 3 days: 13.50±1.87 vs. 5.00±1.55, 7 days: 5.33±1.21 vs. 2.33±1.21, P<0.05 or P<0.01]. (3) Expression of CD34+ cells in the brain of rats in 2-day model group increased significantly, and the highest level appeared at 7 days and decreased at 14 days. Absorbance (A) value of CD34+ cells expression in rat brains of each rG-CSF group was more significant than that in model group (2 days: 43.21±4.41 vs. 22.04±2.95, 3 days: 45.79±1.76 vs. 25.69±2.44, 7 days: 52.09±2.86 vs. 33.04±2.62, 14 days: 29.73±1.99 vs. 16.91±2.95, all P<0.01). (4) The signs of injury to brain in pathological examination were less obvious in 14 days rG-CSF group. CONCLUSION: BMSCs could be induced to enter peripheral blood and "home" to brain tissue after cerebral ischemia. It was showed that BMSCs increased in number at first and then decreased in peripheral blood and brain, the peak number was found on 3rd day in peripheral blood and 7th day in brain. Mobilization with rG-CSF could increase the number of BMSCs in peripheral blood and brain tissue. The effect of mobilization of BMSCs on protecting brain was significant after cerebral ischemia, and effect appeared to be more pronounced with prolongation of mobilization.


Asunto(s)
Células de la Médula Ósea/efectos de los fármacos , Isquemia Encefálica/metabolismo , Encéfalo/metabolismo , Factor Estimulante de Colonias de Granulocitos/farmacología , Animales , Células de la Médula Ósea/citología , Encéfalo/efectos de los fármacos , Encéfalo/patología , Isquemia Encefálica/patología , Femenino , Masculino , Ratas , Ratas Sprague-Dawley
11.
Zhong Xi Yi Jie He Xue Bao ; 7(9): 860-7, 2009 Sep.
Artículo en Chino | MEDLINE | ID: mdl-19747443

RESUMEN

OBJECTIVE: To observe the effects of Naomaitong, a compound traditional Chinese herbal medicine, combined with mobilization of bone marrow mesenchymal stem cells (BMSCs) on neuron apoptosis in rats with cerebral ischemia, and to explore the possible mechanism by detecting the expressions of Fas, FasL and caspase-3 proteins. METHODS: Two hundred and two SD rats were divided into sham-operated group, untreated group, recombinant granulocyte colony-stimulating factor (rG-CSF) group, Naomaitong group and Naomaitong plus rG-CSF group (combination group). Focal cerebral ischemia was induced by intraluminal middle cerebral artery occlusion using a nylon thread with some modification. Rats in the rG-CSF group and the untreated group were administered with rG-CSF 10 microg/(kg x d) by subcutaneous injection 3 d before and 2 d after the operation respectively, once a day, and rats in the Naomaitong group and the combination group were intragastrically administered Naomaitong before and after the operation until sacrificed. Two, three, seven and fourteen days after operation, count of CD34-positive cells in peripheral blood and CD34 expression in brain tissue were determined. General neural function score (GNFS) was evaluated. Neuron apoptosis, expressions of Fas, FasL and caspase-3 in rat's brain were all measured. RESULTS: Count of CD34-positive cells in peripheral blood and CD34 expression in brain tissue were high in the untreated group, and reached the peak at 3 d and 7 d respectively. CD34 expression in brain tissue was increased in each treated group, especially in the combination group. GNFS was increased at 3 d and 7 d in the untreated group, 7 d and 14 d in the rG-CSF group and the combination group. Expressions of Fas, FasL and caspase-3 were increased 2, 3 and 7 d after operation, while expression of FasL at 2 d in the rG-CSF group, expressions of Fas, FasL and caspase-3 in the combination group were decreased. Expressions of Fas, FasL and caspase-3 at 7 d and 14 d in the combination group were lower than those in the rG-CSF group. Meanwhile, expressions of Fas, FasL and caspase-3 were decreased in each group at 14 d as compared with those at 3 d. CONCLUSION: There exists interaction between Naomaitong and BMSC mobilization in the effect of improving nerve function and inhibiting neuron apoptosis in rats after cerebral ischemia. It is implied that Naomaitong combined with BMSC mobilization down-regulates the expressions of Fas and FasL in early phase and then inhibits the apoptosis cascade reaction caused by caspase-3, which causes further inhibition of Fas and FasL expression after cerebral ischemia.


Asunto(s)
Isquemia Encefálica/tratamiento farmacológico , Medicamentos Herbarios Chinos/farmacología , Animales , Apoptosis/efectos de los fármacos , Células de la Médula Ósea , Isquemia Encefálica/metabolismo , Caspasa 3/metabolismo , Proteína Ligando Fas/metabolismo , Ratas , Receptor fas/metabolismo
12.
J Nutr Sci Vitaminol (Tokyo) ; 55(1): 1-8, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19352057

RESUMEN

BACKGROUND: Emerging evidence indicates that maternal oxidative stress during pregnancy could impair fetal growth and that antioxidant vitamins (e.g. vitamins A, E and C) have a significant role in maintaining physiological processes of pregnancy and growth. AIMS: To determine the concentrations of vitamins A, E, and C in pair-matched maternal and cord serum samples of neonate, and thus to investigate the relationship between maternal serum levels of these vitamins at delivery and birth outcomes. METHODS: A total of 143 mother-neonate pairs were recruited into the cross-sectional descriptive study. Demographic information was investigated by questionnaire. After delivery, both cord and maternal blood were collected for quantification of serum levels of vitamins A, E and C by HPLC. RESULTS: Maternal serum levels of vitamins A and E were significantly higher than those in cord serum. In contrast, vitamin C level in cord serum was significantly higher than that in maternal serum. Further, we found that maternal vitamin A status was significantly correlated to both birth weight (r=0.19, p=0.0419) and birth height (r=0.21, p=0.0311), and these were manifested by these findings: (i) per 250.2 g reduction in birth weight concomitant with 1 micromol/L increase in maternal serum vitamin A level (p<0.01; 95% CI: 56.9-451.5); and (ii) per 1% increase in the ratio of serum vitamin A level of neonate to mother concomitant with 0.8 cm increase in birth height (p=0.049; 95% CI: 0.004-1.639). CONCLUSION: Maternal vitamin A, but not vitamins E and C, during pregnancy had a significant effect on birth outcomes. Further studies are necessary to investigate the role of these antioxidant vitamins in fetal growth at various gestation stages.


Asunto(s)
Antioxidantes/análisis , Peso al Nacer , Sangre Fetal/química , Desarrollo Fetal , Recién Nacido/sangre , Fenómenos Fisiologicos de la Nutrición Prenatal , Vitaminas/sangre , Adulto , Ácido Ascórbico/sangre , Análisis Químico de la Sangre , Estatura , China , Estudios Transversales , Femenino , Humanos , Masculino , Estrés Oxidativo , Embarazo , Vitamina A/sangre , Vitamina E/sangre , Adulto Joven
13.
Clin Exp Pharmacol Physiol ; 35(12): 1477-81, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18759861

RESUMEN

1. The haplogroups and polymorphisms of mitochondrial (mt) DNA are associated with longevity. This association is highly geographically dependent. The aim of the present study was to determine the relationship between mtDNA haplogroups, single nucleotide polymorphisms (SNPs) and longevity in the Chinese Uygur population. 2. Ninety-eight Uygur Chinese subjects aged over 90 years (vitality 90+) and 117 healthy young controls living in the Xinjiang Uygur Autonomous Region of China were chosen for the present study. Frequencies of mtDNA haplogroups and SNPs in the subjects were analysed using polymerase chain reaction. The entire mtDNA genome was sequenced and the mtDNA haplogroups and SNPs were determined. 3. Nine haplogroups were identified in the Chinese Uygur population and the frequency of haplogroup J was higher in control subjects than in the vitality 90+ group (odds ratio = 0.384; 95% confidence interval = 0.163-0.906; P = 0.025). Interestingly, most of the SNPs were in the D-loop region, with frequencies higher in the control group than in the vitality 90+ group. 4. In conclusion, mtDNA haplogroups are potentially associated with longevity in the Uygur Chinese population and the D-loop region is strongly involved in ageing-related events.


Asunto(s)
Pueblo Asiatico/genética , ADN Mitocondrial/genética , Haplotipos/genética , Longevidad/genética , Anciano de 80 o más Años , Estudio de Asociación del Genoma Completo/métodos , Humanos , Persona de Mediana Edad , Polimorfismo Genético/genética
14.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 38(4): 306-8, 2003 Jul.
Artículo en Chino | MEDLINE | ID: mdl-12930667

RESUMEN

OBJECTIVE: To study the bonding characteristic of Titanium and RG experiment porcelain. METHODS: 5 specimens with a size of 10 mm x 5 mm x 1.4 mm were cast from pure titanium. Then 1 mm of RG experiment opaque and body porcelain were fused on the surface of the titanium specimens. The interface of titanium and porcelain was analyzed with a scanning electron microscope with energy-despersive spectrometry; 6 metal specimens with the size of 25 mm x 3 mm x 0.5 mm were cast from Ni-Cr alloy and a uniform thickness of 1 mm of VMK 99 porcelain was veneered on the central area of 8 mm x 3 mm 18 metal specimens as the same size were cast from pure titanium. The uniform thickness of 1 mm of VITA TITANKERAMIK porcelain, of Noritake super porcelain Ti-22 and of RG experiment porcelain were veneered on every 6 specimens respectively in the central area of 8 mm x 3 mm. The specimens were subjected to a three-point bending test on a load-test machine with a span of 20 mm, then the failure loads were recorded and statistically analysised. The RG porcelain/titanium crown was fabricated by fusing RG opaque porcelain and body porcelain to cast titanium substrate crown. RESULTS: The SEM results show no porosity and crackle were found in the interface. The energy-dispersive spectrometry show that there are Si, Ti and O in the 1 micro m layer between porcelain and titanium, which suggesting titanium and experiment porcelain bonding well. The three point test showed the fracture force for the combinations of titanium/VITA TITANKERAMIK porcelain, titanium/Noritake super porcelain Ti-22 and titanium/RG experiment porcelain were (7.233 +/- 2.539) N, (5.533 +/- 1.199) N and (6.316 +/- 1.433) N respectively. There were not statistically significant differences among them (t test, P < 0.01). The fracture force for the Ni-Cr alloy/VMK99 porcelain combination (12.733 +/- 3.297) N was significantly greater than those of the cast titanium/porcelain (t test, P > 0.05). The crown was translucent with no crack. CONCLUSION: RG porcelain is well compatible with titanium.


Asunto(s)
Aleaciones de Cerámica y Metal/química , Titanio/química , Porcelana Dental/química
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