Burns ; complications ; immunology ; physiopathology ; Humans ; Hypoxia ; etiology ; immunology ; physiopathology ; Ischemia ; etiology ; immunology ; physiopathology

OBJECTIVETo investigate the effect of Ca(2+) influx through L-type Ca(2+) channels on normal and hyperpolarized membrane potential of arteriole smooth muscle cells (ASMCs) in rats.

METHODSThe ASMCs isolated from normal rats and those with severe hemorrhagic shock were labeled with DiBAC4 (3) for membrane potential detection.

RESULTSCa(2+) influx caused hyperpolarization of the membrane potential in the normal ASMCs but depolarization in the cells from rats with hemorrhagic shock, and this effect could be inhibited by TEA.

CONCLUSIONCa(2+)-activated potassium channels activated by Ca(2+) influx through L-type Ca(2+) channels in normal ASMCs to cause hyperpolarization but leads directly to membrane potential depolarization in ASMCs from rats with severe hemorrhagic shock. This finding can be meaningful for treatment of vascular hyporeactivity in advanced stage of severe shock.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester ; pharmacology ; Animals ; Arterioles ; physiopathology ; Calcium Channel Agonists ; pharmacology ; Calcium Channels, L-Type ; metabolism ; Female ; Male ; Membrane Potentials ; drug effects ; Muscle, Smooth, Vascular ; physiopathology ; Potassium Channels, Calcium-Activated ; metabolism ; Rats ; Rats, Wistar ; Shock, Hemorrhagic ; physiopathology

Objective:To study the antisense oligonucleotide mediated inhibition on telomerase activity and cell proliferation of GBC-SD cell.Methods:We design the antisense,sense,and random oligonucleotide with phosphoric acid modification for the hTR(Human Telomerase RNA)template sequence.MTT and PCR methods were used to observe the inhibition on telomerase activity and cell proliferation of GBC-SD cell ,and fibroblast cells were used as control group.Results:PS-ODN can lead to the reduction of cell survival rate of GBC-SD cell,wich dosage dependence.Tne experimental group cell detected by scanning electron appeared apoptotic feature.Conclusion:PS-ODN can inhibit telomerase activity of GBC-SD cell effectively and induce the cell apoptosis.

The intestinal epithelial barrier serves a dual role: to keep harmful external agents out of the body and to allow beneficial nutrients to enter the body. Tight junction (TJ) is of crucial importance for the barrier function. Over the past 15 years, some of the molecular events underlying the epithelial barrier regulation have been described. This forum introduces briefly the molecular structure of TJ and its regulation in gut barrier. It was shown that gut barrier function was impaired as early as 5 minutes post burn and became worst by 4 hours. In this forum the mechanism of gut barrier injury in burns is described, and it includes 4 aspects: the phosphorylation of TJ protein and perijunctional actin-myosin ring, the reduction of TJ proteins expression, the endocytosis of TJ proteins, and the apoptosis and necrosis of the epithelial cells. It is well known that the increase in gut permeability promotes bacterial translocation in burns. Moreover, a new auto-digestion theory of gut in shock and MODS was recently raised. Therefore, protection against gut barrier damage has again been recognized as a therapeutic target in shock and MODS treatment.
Actins ; metabolism ; Apoptosis ; Burns ; metabolism ; Endocytosis ; Epithelial Cells ; metabolism ; Humans ; Intestinal Mucosa ; metabolism ; Membrane Proteins ; metabolism ; Multiple Organ Failure ; physiopathology ; Myosins ; metabolism ; Permeability ; Phosphorylation ; Shock ; metabolism ; Tight Junctions ; metabolism

Objective: To compare the effects of 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP)- and silane-based primers with those of MDP-based primers on zirconia-resin bonding via multiple levels of aging. Methods: Zirconia blocks were divided into 4 groups (n = 21) according to the primer used: MDP-based Z-Prime Plus (ZP), silane-based Monobond-S (MS), MDP- and silane-based Clearfil Ceramic Primer (CCP) and no primer (Blank). After pretreatment with or without the primers followed by bonding with cement Duo-Link, each group was subdivided into 3 subgroups (n = 7) according to aging level: 24 hours of water storage at 37 ℃ (24 h), 30 days of water storage at 37 ℃(30 d), and 30 d plus 3 000 thermal cycles (30 d/TC). After aging, shear bond strength (SBS) tests and failure mode analyses were conducted Results: ZP, MS and CCP groups had greater SBSs than did the BLANK group (P<0.01). From 24 h to 30 d, the shear bond strength significantly increased (P<0.05); however, the shear bond strength decreased significantly from 30 d to 30 d/TC (P<0.01) and fell below baseline (30 d/TC vs. 24 h, P<0.01). Within the primer groups, CCP exhibited a higher SBS than ZP and MS at each aging level (P<0.001). The bonding strength of ZP was greater than that of MS at 30 d (P = 0.029) but lower than that of MS at 30 d/TC (P = 0.037). From 30 d to 30 d/TC, the percent decrease in the bonding strength of ZP was significantly greater than that of MS (82.43% vs. 64.90%). Conclusion MDP-based primers function better for zirconia-resin bonding when they contain silane coupling agents.

OBJECTIVETo prepare zirconia toughened nano-composite alumina ceramic powder for dental application. Physical and chemical property of the prepared material were tested, and the effect of development technology on composite powder was also studied in this study.

METHODSNano-composite alumina powder was prepared by surface-induced precipitation method. The effect of pH value and dispersing agent content on volume of alumina suspension sediment was recorded. The effect of ultrasonic time on agglomeration was measured also. X ray diffraction (XRD) was used to analyze powder phase before and after the stabilizer was added. Scanning electronic microscope (SEM) was applied for characterizing the specimen.

RESULTSThe dispersion was better at pH=9 and wt (dispersing agent) = 0.2% approximately 0.3%. Selecting proper ultrasonic time can decrease the agglomeration of powders and lower the average particle size. XRD analysis indicated that the phase composition of the prepared nano-composite ceramic powder was shown as alpha-Al2O3, t-ZrO2 and a small amount of m-ZrO2 after the addition of stabilizer. Through SEM observation, nanometer-sized ZrO2 particles (80 approximately 100 nm) were uniformly located on the surface of submicrometer alumina grains.

CONCLUSIONSBy choosing appropriate preparation method, weakly agglomerated powders with fine particle size can be obtained. The zirconia part of nano-composite powder was transmitted to partially stabled zirconia after the use of stabilizer.

Aluminum Oxide ; chemistry ; Dental Porcelain ; chemistry ; Hydrogen-Ion Concentration ; Powders ; Zirconium ; chemistry

Exposure of gingival margin is frequently observed in anterior teeth aesthetic restoration. How to obtain an expected result is a significant challenge during prosthodontic treatment. The present article discussed gingival biotype, conditions of periodontal tissue, location of margin of restoration, gingival retraction, and provisional restoration, etc, which would affect the final aesthetic outcome of anterior teeth restorations. The aim of this article is to figure out how to effectively avoid the exposure of gingival margin in anterior teeth aesthetic restoration, and to improve the finally aesthetic outcome of anterior teeth restoration.
Esthetics ; Esthetics, Dental ; Gingiva ; Humans ; Prosthodontics

OBJECTIVETo evaluate the influence of veneer application on failure behavior and reliability of lithium disilicate glass-ceramic (LDG) crowns of maxillary first molar, and thus to reveal the failure mechanism of bilayered LDG crowns.

METHODSTwenty-six LDG maxillary first molar crowns were fabricated in a dental laboratory using IPS e. max Press or IPS e. max Press/Ceram. The crowns were randomly assigned into two groups (with or without veneer application) with thirteen in each group. The crowns were cemented on composite resin dies. After storage in water for one week, the sliding-contact fatigue test was performed by sliding the steatite ceramic ball indenter (6 mm in diameter) from central fossa up to the lingual surface of disto-buccal cusp, cyclic loaded 1 200 000 times with a weight of 100 N at 2 Hz with a fatigue chewing simulator. Survived specimens were subjected to single-load-to-fracture testing using a steatite ceramic ball of 6 mm in diameter at a cross-head speed of 0.5 mm/min in a universal testing machine. Fracture load values were recorded and analyzed with t test. Weibull modulus was calculated to evaluate structure reliability. Fractographic analysis was carried out to determine fracture modes of the failed specimens by a stereomicroscope and a scanning electron microscope (SEM).

RESULTSStatistical analysis results indicated a significant difference of the fracture load values between monolithic group [(2071.23 ± 397.05) N] and bilayered group [(1483.41 ± 327.87) N] (P < 0.001). Monolithic and bilayered groups present similar Weibull modulus (95% confidence interval) as 6.15 (5.15 ∼ 7.15) and 5.54 (4.01 ∼ 7.08) respectively, with no significant difference (the confidence bounds overlapped with each other). Bulk fracture initiating from the middle of oblique ridge of the first maxilla molar was the primary failure mode of monolithic/bilayered LDG crowns. Crack propagation initiated from core-veneer interfacial defects was another major failure mode of bilayered all-ceramic crowns.

CONCLUSIONSVeneer application has some influence on fatigue failure of LDG crowns, but shows no effect on structure reliability. Accumulated damage combined with tensile stress concentration on the surface of veneer layer and defects within core-veneer interface lead to initiating of cracks. The mechanical property of veneering materials should be increased, and procedure of veneer application should be standardized and improved in order to reduce the failure rate of LDG molar crowns.

Crowns ; Dental Porcelain ; chemistry ; Dental Restoration Failure ; Materials Testing ; Molar

To investigate and compare the expression of intercellular adhesion molecule-1 (ICAM-1) in different organs of the mice with endotoxic shock induced by lipopolysaccharide (LPS), protein and mRNA of ICAM-1 were measured by Western blotting and RT-PCR respectively in different organs of BALB/c mice administered intraperitoneally with 5 mg/kg LPS. The results showed that the constitutive expression of ICAM-1 protein and mRNA was the greatest in the lungs, followed by the spleen, kidney and intestine. After LPS stimulation, the upregulation of ICAM-1 was still greatest in the lungs, followed by the liver, spleen, heart, kidney and intestine. Compared with the normal mice, the expression of ICAM-1 protein in endotoxic shocked mice increased by 4.5-fold in the lungs, 3.0-fold in the kidney, 1.5-fold in the spleen; the expression in the liver and heart was negative under normal condition and changed into positive during endotoxic shock; but ICAM-1 expression in the intestine did not change significantly. The expression of ICAM-1 mRNA also increased consistently. These data highlight that LPS can up-regulate ICAM-1 protein and mRNA expression in different tissues of the mice with endotoxic shock. The difference in ICAM-1 expression among the organs may lead to different sensitivity of organ damage in endotoxic shock. This suggests that inhibition of ICAM-1 expression may be a useful principle for prevention and treatment of endotoxic shock.
Animals ; Intercellular Adhesion Molecule-1 ; biosynthesis ; Kidney ; metabolism ; Lipopolysaccharides ; Lung ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; RNA, Messenger ; biosynthesis ; Shock, Septic ; chemically induced ; metabolism

OBJECTIVETo investigate the dose and time-dependent effects of lipopolysaccharide (LPS) on cytoskeletal F-acitn and G-actin reorganizations by visualizing their distribution and measuring their contents in human umbilical vein endothelial cell line ECV-304.

METHODSF-actin was labeled with rhodamine-phalloidin and G-actin with deoxyribonuclease I (DNase I)conjugated with fluorescein isothiocyanate (FITC). Contents of cytoskeletal proteins were obtained by flow cytometry.

RESULTSF-actin was mainly distributed peripherally in endothelial cells under normal conditions. LPS stimulation caused the formation of stress fibers and filopodia. G-actin was normally seen in perinuclear and nuclear areas in control ECV-304 cells. Under LPS stimulation, G-actin dots appeared in the cytoplasmic region. The actin disorganization was accompanied by the time- and dose- dependent decrease in F-actin pool and increase in G-actin pool.

CONCLUSIONSLPS can induce characteristic morphological alterations of actin cytoskeleton and formation of intercellular gap in endothelial cells, accompanied by changes in F-actin and G-actin pools.

Actins ; drug effects ; Analysis of Variance ; Cells, Cultured ; Deoxyribonuclease I ; Dose-Response Relationship, Drug ; Endothelial Cells ; chemistry ; Escherichia coli ; Fluorescein-5-isothiocyanate ; Fluorescent Dyes ; Humans ; Lipopolysaccharides ; pharmacology ; Phalloidine ; Rhodamines ; Umbilical Veins ; cytology