'Bronze teeth' reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from outside to inside. These attributes confer human teeth with effective mastication ability. Understanding the various mechanical properties of human teeth and dental materials is the basis for the development of restorative materials. In this study, the elastic properties, dynamic mechanical properties (visco-elasticity) and fracture mechanical properties of enamel and dentin were reviewed to provide a more thorough understanding of the mechanical properties of human teeth.
Biomechanical Phenomena ; Dental Enamel ; physiopathology ; Dentin ; physiopathology ; Humans ; Mastication ; Tooth ; physiopathology

OBJECTIVETo evaluate the effects of taurine in diet on the expression of inducible nitric oxide synthase (iNOS) in rat lung induced by silica.

METHODSWistar rats were established by direct tracheal instillation of silica into rat lungs exposed surgically, and the animals of taurine-treated group were silica-instilled with a diet containing taurine. The taurine concentration of serum was analyzed by means of HPLC. The expression of iNOS protein in paraffin-embedded lung sections with Streptavidin/peroxidase (SP) immunohistochemistry on tissue microarray was measured by Image-Pro Plus.

RESULTSThe concentration of taurine in serum of taurine-treated group was significantly higher than those in saline-treated and silica-treated groups (P < 0.05). The activities of total NOS and iNOS in BALF supernatant and iNOS positive area percentage of rat lung in silica-treated group were at the peak on 14th day, which were 1.84 U/ml, 1.12 U/ml and 5.42% more respectively than those in saline-treated group (P < 0.05). There were no significant differences between taurine-treated group and silica-treated group in total NOS and iNOS activities of BALF supernatant, and iNOS positive area of the lung (P > 0.05).

CONCLUSIONTreatment with taurine hardly influences on the increase in expression of nitric oxide synthase in rat lung induced by silica dust.

Animals ; Bronchoalveolar Lavage Fluid ; chemistry ; Female ; Lung ; drug effects ; enzymology ; Male ; Nitric Oxide Synthase Type II ; biosynthesis ; Rats ; Rats, Wistar ; Silicon Dioxide ; toxicity ; Taurine ; blood ; pharmacology

Antibody against the angiotensin AT1 receptor (AT1-Ab) could disturb placental development. The placenta is the key organ between mother and fetus. Placental damage will seriously impair fetal growth and development in utero, leading to intrauterine growth restriction (IUGR). Based on the fetal origins of adult disease (FOAD) hypothesis, IUGR could increase a propensity to develop adult onset cardiovascular disease (CVD). The present study was designed to determine whether vascular function has changed in the adult offspring of AT1-Ab positive pregnant rats. Twenty four female rats (8-week-old, AT1-Ab negative) were randomly divided into two groups, immunized and vehicle groups. Immunized group received active immunization to establish AT1-Ab-positive model, while vehicle group was subjected to Freund's adjuvant without antigen. After 8 weeks of immunization, the antibody titers in sera from the female rats were detected by enzyme-linked immunosorbent assay (ELISA). Then all the female rats were mated with normal Wistar male rats and became pregnant. Immunized/vehicle group offspring rats (I offspring/V offspring) were raised to 40-week-old under standard chow feeding. Then the two groups' offspring rats were given a high-salt diet for 12 weeks (4% NaCl in chow feeding). Systolic blood pressure (SBP) was measured dynamically by noninvasive blood pressure system. The vascular ring experiment was performed to detect vascular function and reactivity. As detected by ELISA, the titers of antibody peaked at the 8th week (OD values: 2.75 ± 0.08 vs 0.33 ± 0.01, P < 0.01 vs vehicle group at the same time point). There was no significant difference of SBP between the two groups' offspring rats during the high-salt diet (P > 0.05). Isolated thoracic aortic rings of I offspring had significantly decreased constriction under norepinephrine treatment (P < 0.01 vs V offspring) and significantly decreased dilation under acetylcholine treatment (P < 0.05 vs V offspring). These results suggest that the offspring of AT1-Ab-positive pregnant rats are more susceptible to vascular functional abnormality while being fed high-salt diet.
Animals ; Antibodies ; blood ; Cardiovascular Diseases ; etiology ; physiopathology ; Disease Susceptibility ; Female ; Fetal Growth Retardation ; physiopathology ; Immunization ; Pregnancy ; Prenatal Exposure Delayed Effects ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; immunology ; Sodium Chloride, Dietary ; administration & dosage ; adverse effects

OBJECTIVETo evaluate the effects of taurine in diet on the expression of type I and III collagen and collagen ratio at different time points in rats lung by image process technology.

METHODSWistar rats were randomly divided into three groups: the saline instilled with a control diet (the saline treated group); silica instilled with a control diet (the silica treated group); and silica instilled with a diet containing 2.5% taurine (the taurine treated group). Animal models were established by the direct tracheal instillation of silica into rat lungs exposed surgically. The taurine concentration of serum was analyzed by means of HPLC. Paraffin embedded lung sections were stained with Sirius red. Polarization microscopy and Image Pro Plus Version 4.5 for windows were used for detecting type I and III collagen.

RESULTSThe concentration of taurine in serum of the taurine treated group was significantly elevated compared to the saline treated and silica treated group (P < 0.05 or P < 0.01). Sirius red polarization microscopy showed that type I and III collagen positive area percentage were elevated in the silica treated rats compared with the saline treated group. On the 7th, 14th, 21st, 28th day after silica instillation type I collagen positive area percentage was increased by 3.84, 3.77, 3.73, 9.83 respectively (P < 0.01), and type III collagen positive area percentage were elevated by a little in the silica treated rats compared with saline treated group. The taurine treatment significantly decreased elevation of silica type I collagen positive area percentage of lung by 2.39, 1.62, 7.13 at the 7th, 21st, 28th day respectively (P < 0.05 or P < 0.01), and type III collagen positive area percentage of lung by 2.62 at the 28th day (P < 0.05) compared with the silica treated group. The ratio of type I to III collagen was increased from the 7th day to 28th day after silica instillation, and reached 1.87 at the 28th day with the maximal ratio in the silica-treated group.

CONCLUSIONTreatment with taurine can effectively attenuate type I and III collagen expression in the rat lung induced by silica particles at different time points in our study.

Animals ; Collagen Type I ; biosynthesis ; Collagen Type III ; biosynthesis ; Female ; Lung ; drug effects ; metabolism ; Male ; Random Allocation ; Rats ; Rats, Wistar ; Silicon Dioxide ; toxicity ; Taurine ; pharmacology

Objective:To observe influence of benazepril combined trimetazidine on blood levels of follistatin-like 1 (FSTL1)and platelet activating factor (PAF)and vascular endothelial function in patients with coronary heart dis-ease (CHD)complicated heart failure (HF).Methods:A total of 120 CHD patients with chronic heart failure were selected from our hospital.They were randomly and equally divided into benazepril group and combined treatment group (received benazepril combined trimetazidine therapy),both groups were treated for six months.Serum Blood levels of N-terminal pro brain natriuretic peptide (NT-proBNP),FSTL1 and PAF,endothelial progenitor cells (EPCs)count and fore brachial artery endothelium dependent diastolic-systolic function (FMD)before and after treatment were measured and compared between two groups.Results:Compared with before treatment,there were significant rise in left ventricular ejection fraction (LVEF),6min walking distance (6MWD),EPCs and FMD,and significant reductions in serum levels of NT-proBNP,FSTL1 and PAF after treatment in two groups,P <0.05 or <0.01;compared with benazepril group,there were significant rise in LVEF [(41.94±9.19)% vs.(46.15±10.04)%], 6MWD [(333.94±58.29)m vs.(383.14±77.84)m],EPCs [(0.059±0.029)pg/ml vs.(0.083±0.014)pg/ml]and FMD [(7.53±2.02)% vs.(8.24±1.42)%],and significant reductions in serum levels of NT-proBNP [(2.74±0.69) ng/ml vs.(2.05±0.34)ng/ml],FSTL1 [(5.38±1.29)ng/ml vs.(4.64±0.84)ng/ml]and PAF [(5.16±0.92)μg/ml vs.(4.20±1.05)μg/ml]in combined treatment group,P <0.05 or <0.01.Conclusion:Benazepril combined trimeta-zidine can effectively reduce blood levels of NT-proBNP,FSTL1 and PAF,and promote vascular endothelial function re-covery in patients with coronary heart disease complicated chronic heart failure.

Objective:The current study was designed to identify molecular mechanism of antitumor effect produced by NCTD(norcantharidin) in human breast cancer cell line. Methods: MCF- 7 cells were grown in standard conditions. At the indicated time points after NCTD treatment, evaluation of apoptotic morphology by light microscopy, analysis of chromatin condensation by electron microscopy, determination of the percentage of apoptotic cells by flow cytometry and Western blot analysis for detecting of bcl- 2 gene expression were conducted. Results: Differences in cellular morphology were observed between NCTD- treated and control MCF- 7 cells. Cell shrinkage, cell budding and chromatin condensation were observed in the cells treated with 10 μ g/ml NCTD for 12 hours. Percentage of apoptotical cells was increased while the expression of bcl-2 products was decreased with the increasing of incubation time. Conclusion: The results indicate that one of the major antitumor mechanisms of NCTD may be through inducing cell apoptosis which related to the regulation of bcl- 2 gene expression.

UNLABELLEDTo study the clinical significance of the expression of antiapoptosis gene, survivin and bcl-2, and proapoptosis gene, Fas and bax, in acute myeloid leukemia (AML), RT-PCR was used to examine the expression of survivin and flow cytometry (FCM) to detect the expression of Fas, bcl-2, bax and bcl-2/bax ratio in 68 cases of AML. The results demonstrated that: (1) The positivity of survivin mRNA expression was significantly higher in AML compared to control (70.6% vs 30%, P < 0.05). (2) The expression of Fas and bcl-2 in AML before treatment was significantly higher than that in control (P < 0.001), but the bax expression did not (P > 0.05). (3) The survivin-positive AML cases showed a significantly lower Fas and higher bcl-2 expression in comparison with survivin-negative ones (P < 0.01 and P < 0.001, respectively), but the bax did not (P > 0.01). (4) Survivin-positive AML cases had a lower CR rate as compared with survivin-negative cases (64.6% vs 90%, P < 0.05). (5) The survivin-positive CR cases showed a decreased expression of Fas and bcl-2 after treatment in comparison with pretreatment expression (P < 0.001), but the bax expression remained unchanged before and after therapy. The survivin-positive NR cases showed a significantly decreased Fas and increased bcl-2 expression as compared with pretreatment expression (P < 0.001). bcl-2/bax ratio was also significantly higher in NR cases.

IN CONCLUSION70.6% AML cases showed positive for survivin expression with a lower CR rate, the survivin-positive AML showed a low Fas with high bcl-2 expression and bcl-2/bax ratio as compared to the survivin-negative cases.

Adolescent ; Adult ; Aged ; Antineoplastic Agents ; therapeutic use ; Biomarkers, Tumor ; biosynthesis ; genetics ; Bone Marrow Cells ; drug effects ; metabolism ; Female ; Flow Cytometry ; Gene Expression Regulation, Neoplastic ; Humans ; Inhibitor of Apoptosis Proteins ; Leukemia, Myeloid, Acute ; drug therapy ; genetics ; metabolism ; Male ; Microtubule-Associated Proteins ; genetics ; Middle Aged ; Neoplasm Proteins ; Proto-Oncogene Proteins ; biosynthesis ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; RNA, Messenger ; drug effects ; genetics ; metabolism ; bcl-2-Associated X Protein ; fas Receptor ; biosynthesis

OBJECTIVETo investigate the roles of cyclin D1/CDK4-E2F-1/4 pathway in cell cycle changes of human embryo lung fibroblasts (HELF) induced by two different benzo(a)pyrene [B(a)P] treatment models.

METHODSTwo B(a)P treatment models: HELF were treated by 2 micromol/L B(a)P for 24 hours; HELF were treated by 100 micromol/L B(a)P three times 24 hours each and provide with some characteristics of transformed cells (T-HELF). Changes of cell cycle and the expression of cyclin D1, CDK4 and E2F-1/4 were checked using the flow cytometry and Western bolt analysis.

RESULTSAfter 24 hours 2 microml/L B(a)P treatment, the HELFs in the G(1) phase was decreased. In HELF transfected with antisense cyclin Dl (A-Dl) and antisense CDK4 (A-K4), the expression of cyclin Dl and CDK4 blocked the cell cycle changes from the G(1) phase to the S phase induced by B(a)P. The overexpression of cyclin Dl and E2F-1 in HELF was induced by B(a)P. The E2F-1 overexpression in A-D1 induced B(a)P was inhibited. The E2F-4 expression was decreased and the CDK4 expression was increased significantly in A-K4 after B(a)P treatment. Most of T-HELF transfected with antisense cyclin Dl (T-A-Dl) and antisense CDK4 (T-A-K4) were retained in G(1) phase. The cyclin Dl expression in T-HELF was increased significantly compared with that in HELF. The E2F-4 expression in T-A-Dl and T-A-K4 was increased significantly compared with that in T-HELF.

CONCLUSIONB(a)P induces the cell cycle changes through cyclin D1/CDK4-E2F-1/4 pathway in HELF treated by 2 micromol/L B(a)P while it induces cell cycle changes through cyclin D1/CDK4-E2F-4 pathway in T-HELF.

Benzo(a)pyrene ; pharmacology ; Blotting, Western ; Cell Cycle ; drug effects ; Cells, Cultured ; Cyclin D1 ; biosynthesis ; Cyclin-Dependent Kinase 4 ; biosynthesis ; Dose-Response Relationship, Drug ; E2F1 Transcription Factor ; biosynthesis ; E2F4 Transcription Factor ; biosynthesis ; Fibroblasts ; cytology ; drug effects ; metabolism ; Flow Cytometry ; Humans ; Lung ; cytology ; embryology

Adult ; Female ; Hamartoma ; complications ; diagnosis ; surgery ; Humans ; Kidney Calculi ; complications ; Spleen ; pathology ; surgery ; Splenectomy ; methods ; Splenic Diseases ; complications ; diagnosis ; surgery

Baculoviridae ; genetics ; Cloning, Molecular ; DNA, Recombinant ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; genetics ; Genetic Vectors ; Hepatitis A virus ; genetics ; immunology ; Humans ; Immunoglobulin Fab Fragments ; genetics ; Plasmids ; genetics ; Polymerase Chain Reaction ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection