'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

Objective　To compare the Immunoreactivity of various HEV Antigen with Anti-HEV IgM. Methods Solid-phase enzyme immunoassay( EIA ) was developed for detecting anti-HEV IgM by using synthetic peptides E30, E42, E33, and recombinant antigen from HEV ORF-2. Results Of 60 anti-HEV positive sera by using E30, E42, E33 and recombinant antigen as coating antigen, Anti-HEV IgM positive rates were 76.7%, 26.6%, 18.3% and 66.7% respectively. In Acute-phase and convalescence-phase sera of the patients with Hepatitis E, Anti-HEV IgM positive rate was 90% and 3.3% respectively. Conclusions The HEV E30-based EIA will be very useful in the early diagnosis of Hepatitis E.

Objective To retrospectively evaluate the mammographic features of breast ductal carcinoma in situ (DCIS)and DCIS with small invasive foci,and to analyze the correlation between the mammographic findings and the prognostic biologic factors.Methods The mammographic examination was performed in 95 consecutive women with breast DCIS(n = 50)and DCIS with invasive foci(n = 45 ).The prognostic biologic factors including progesterone receptor(PR),C-erbB-2,and p53 were evaluated in 62 of 95 cases.Categorical data were expressed as percentages and analyzed by using the X~2 test,and furthermore the odds ratio was measured.Results(1)Only one abnormality was seen on mammography in 62 patients. Combined two abnormalities on mammography were seen in 26 patients.Mammograms were normal in 7 patients.(2)Calcifications with or without other abnormality were noted in 62 cases.Of them,73% (n =45)had higher probability of malignancy calcifications and the others were intermediate concern calcifications.Clustered calcifications(36 lesions)was the most common distribution,which usually accompanied by another abnormality.And then were segmental(18 lesions)distributed pattern.As far as the shape of mass (n = 22)was concerned,the oval shaped lesion(13 cases)was the most common,and the margin of the mass appeared as ill-defined in 15 eases,microlobulated in 1,circumscribed in 4,and obscured in 2,respectively.Isodensity mass had a higher frequency in this group(12/22,55%).Other non-calcification findings included architecture distortion(7 cases),local asymmetry (15 cases),global asymmetry (5 cases),and solitary dilated duct (3 cases),and most of them accompanied with other signs. (3)For expression profile of the biological factors,significant differences were found among malignant calcification group,intermediate concern calcification group,and non-calcification group. The odds of PR positive for the lesions noted as non-calcification were 11.00 times higher (X~2 =8.571 ,P=0.003 ;95% CI, 1.998—60.572)than the lesions noted as intermediate concern calcifications,and 8.80 times higher (X~2 = 9.748,P=0.002 ;95% CI,2.024—38.253)than the lesions noted as malignant calcifications.The odds of C-erbB-2 positive for the lesions showed as malignant calcifications were 12.35 times higher (X~2=7.353, P=0.007 ;95% CI,1.447—105.443)than the lesions showed as non-calcification,and 5.74 times higher (X~2=4.977,P = 0.026;95% CI,1.110—29.645)than the lesions showed as intermediate concern calcifications.Conclusion The mammographic features of DCIS and DCIS with small invasive foci were characteristic.Mammographic findings could be a prognostic markers,which could provide a possibility for making a treatment plan.

BACKGROUNDTrichosporon asahii (T. asahii) is one of the most important pathogenic fungus in the genus of trichosporon. Although the species identification of T. asahii was based upon the complicated results of morphologic, biochemical and biologic examination, the morphology characteristic is still the first clue to the species. Some common structures of T. asahii had been described such as arthrofilaments and arthroconidia, but other important structures of T. asahii were unclear.

METHODSSix strains of T. asahii were incubated on the slant and micro culture of Sabouraud's dextrose agar at 30 degrees C for 7 days. Samples were fixed using 2% paraformaldehyde and 2.5% glutaraldehyde. T. asahii was observed under scanning electron microscope and transmission electron microscope.

RESULTSThe detailed characteristics of the diverse sites of germination, as well as some uncommon structures such as giant cell, sarcinate, and club-shaped macroconidia, were presented. The pseudohyphae of T. asahii were noted to produce true hyphae, either along the longitude axis or on the flank. T. asahii was noted to have blastic and thallic conidiation. Digitated branches, trichoid structures and septa inside the spores were detected.

CONCLUSIONThese results may add our knowledge to the structure and development of T. asahii.

Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Spores, Fungal ; growth & development ; ultrastructure ; Trichosporon ; growth & development ; ultrastructure

The effects of two different sample labeling methods on background signal intensities for high-density 60mer oligonucleotide microarray were investigated. Peripheral blood samples from five disease and five control subjects were collected. Total RNA targets from peripheral blood mononuclear cells were extracted and labeled with RD-PCR protocol, which were hybridized to Agilent Human 1B oligonucleotide microarrays in a two-color comparative format. The positive control targets were labeled with the directly incorporated fluorescently-labeled dNTP labeling. The SPSS program was performed to test normality of the dataset, variance homogeneity between the groups, coefficients of variation (CV) and analysis of variance. The results showed that the background signal intensities of Cy3 channel were higher than those of Cy5 channel. The differences of background signal intensities between the RD-PCR approach and the directly incorporated fluorescently-labeled dNTP labeling were extremely significant (P- Cy3

OBJECTIVEThe purpose of this study was to assess the feasibility of fluorescent 2-deoxyglucose analog, 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG), that could be taken up by breast cancer cells highly expressing glucose transporter 1 (GLUT-1). The purpose of this study was to clarify if a fluorescent 2-deoxyglucose analog, 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG), can be taken up by breast cancer cells highly expressing glucose transporter 1 (GLUT-1), and to assess whether it can be used as a targeting imaging agent.

METHODSThe expressions of GLUT-1 mRNA and protein in breast cancer MDA-MB-231 cells were detected by RT-PCR and immunohistochemistry, respectively. The difference of GLUT-1 protein expression between breast cancer MDA-MB-231 cells and MCF-7 cells was compared by Western blot. Secondly, MDA-MB-231 cells which were grown in 6-well plates were incubated with 2-NBDG, and the result of 2-NBDG uptake was analyzed by fluorescence microscopy and flow cytometry. The difference of 2-NBDG absorption in MDA-MB-231 and MCF-7 cells was compared by flow cytometry.

RESULTSThe results of RT-PCR and immunohistochemistry confirmed that MDA-MB-231 cells highly expressed GLUT-1. Furthermore, Western blot revealed that GLUT-1 expression of MDA-MB-231 cells (0.946 ± 0.007) was higher than that in the MCF-7 cells (0.833 ± 0.010). Fluorescence microscopic and flow cytometric analysis showed that 2-NBDG was uptaken rapidly by MDA-MB-231 cells. Addition of 50 mmol/L D-glucose to the media with 2-NBDG reduced its uptake by 46.0%. Moreover, flow cytometry indicated that the fluorescence intensity of MDA-MB-231 cells (25.10 ± 0.57) was higher than that of MCF-7 cells (10.12 ± 0.62) when incubated with 2-NBDG for 20 minutes.

CONCLUSIONThe preliminary data clearly demonstrate that 2-NBDG is taken up and accumulated in breast cancer cells that highly express GLUT-1, and may be used as an optical probe for glucose uptake in hypermetabolic malignant cells.

4-Chloro-7-nitrobenzofurazan ; analogs & derivatives ; pharmacokinetics ; Blotting, Western ; Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Deoxyglucose ; analogs & derivatives ; pharmacokinetics ; Female ; Flow Cytometry ; Glucose Transporter Type 1 ; genetics ; metabolism ; Humans ; Immunohistochemistry ; RNA, Messenger ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the influence of lead exposure in rats during the developmental stage on the expression of leptin in plasma, cerebrospinal fluid, and hippocampus, as well as investigating whether leptin is associated with the mechanism of cognitive impairment induced by lead exposure.

METHODSThe rat model of cognitive impairment after chronic lead exposure was established by adding lead acetate into drinking water. According to the concentration of lead acetate in drinking water, the rats were divided into control (0 ppm), low-lead (50 ppm), medium-lead (200 ppm), and high-lead groups (1 000 ppm), with 16 rats in each group. Atomic absorption spectrometry was used to measure the content of lead in the plasma, cerebrospinal fluid and hippocampus. ELISA was used to measure the level of leptin in the plasma and cerebrospinal fluid. Immunohistochemistry was used to observe the distribution of leptin protein in the hippocampus. Western blot was used for relative quantification of leptin proteins in the hippocampus.

RESULTSCompared with the control group, the lead exposure groups showed significant increases in the content of lead in blood, cerebrospinal fluid, and hippocampus (P<0.01), as well as significant reductions in the levels of leptin in plasma and cerebrospinal fluid (P<0.05). The results of immunohistochemical staining showed that leptin was mainly distributed in the cytoplasm of pyramidal neurons in the hippocampal CA region. The results of Western blot showed that compared with the control group, the three lead exposure groups showed a slight increase in the protein expression of leptin in the hippocampus (P>0.05).

CONCLUSIONSLead exposure can reduce the levels of leptin in plasma and cerebrospinal fluid in rats, which may be associated with the mechanism of cognitive impairment induced by lead exposure.

Animals ; Apoptosis ; drug effects ; Cognition ; drug effects ; Female ; Hippocampus ; chemistry ; drug effects ; pathology ; Lead ; blood ; toxicity ; Leptin ; analysis ; blood ; cerebrospinal fluid ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the relationship between RASSF1A gene expression and DNA methylation or histone modification in laryngeal carcinoma tissues.

METHODSChromatin immunoprecipitation (ChIP), methylation specific polymerase chain reaction (MSP) and realtime quantitative reverse transcription polymerase chain reaction (realtime RT-PCR) were used to analyze RASSF1A gene promoter region histone H3 lysine 9 methylation, H3 lysine 4 methylation, H3 lysine 9 acetylation, DNA methylation, and RASSF1A gene expression in laryngeal carcinoma tissue of 50 cases.

RESULTSDNA methylation rate of gene RASSF1A was 62% in 50 cases of laryngeal carcinoma, but no DNA methylation was found in normal control group, with a significant difference (χ(2) = 15.381, P < 0.05). DNA methylation had no correlation with age, gender, differentiation degree, T stage, pathological type and lymph node metastasis (P > 0.05). The affection of DNA methylation group was more than unmethylation group to expression of gene RASSF1A (t = -3.108, P < 0.01). There was positive correlation between RASSF1A deletion and gene hypermethylation or between H3 lysine 9 methylation of RASSF1A gene promoter and DNA methylation in laryngeal carcinoma tissue(r = 0.816, P < 0.05), but there was negative correlation between H3 lysine 4 methylation of RASSF1A gene promoter and DNA methylation (r = -0.837, P < 0.05) and no correlation between H3 lysine 9 acetylation and DNA methylation (r = -0.383, P > 0.05).

CONCLUSIONSLaryngeal tumor suppressor gene RASSF1A promoter methylation is a key factor down-regulating the gene expression, and histone modifications also plays an important role in tumor development.

Adult ; Aged ; CpG Islands ; DNA Methylation ; Female ; Gene Deletion ; Gene Expression Regulation, Neoplastic ; Gene Silencing ; Histones ; genetics ; metabolism ; Humans ; Laryngeal Neoplasms ; genetics ; metabolism ; Male ; Middle Aged ; Neoplasm Staging ; Promoter Regions, Genetic ; Tumor Suppressor Proteins ; genetics

OBJECTIVETo investigate how to establish good eating behavior and correct bad eating habits in infants by means of the child health care outpatient clinic and to promote the growth and development of infants.

METHODSInfants aged 0-3 months, who were randomly selected from the urban area of Chongqing, were divided into intervention and control groups. The infants in the intervention group received all intervention measures in the study, while those in the control group received conventional health care. Both groups were subjected to regular monitoring of eating behavior indices including time of introduction of foods, frequency of adding complementary foods and intake frequency of unhealthy foods to analyze the effect of intervention.

RESULTSIn the intervention group, foods were introduced at a reasonable time (P<0.01). Compared with those in the control group, the children aged 9 and 12 months in the intervention group had a significantly higher intake frequency of meat, vegetables and fruits (P<0.01) and a significantly lower intake frequency of sweet drinks (P<0.05), children aged 18 and 24 months in the intervention group had a significantly lower intake frequency of sweet drinks (P<0.01), and the children aged 24 months in the intervention group had a significantly lower intake frequency of ice cream (P<0.01).

CONCLUSIONSEating behavior intervention can promote the proper introduction of foods and regular addition of supplementary foods, as well as decrease the intake frequency of unhealthy foods such as sweet drinks and ice cream, thus improving the eating behavior of infants.

China ; Feeding Behavior ; Female ; Humans ; Infant ; Infant, Newborn ; Male

OBJECTIVETo investigate the protective effect of astragalus on testis tissues following unilateral testicular torsion/detorsion.

METHODSThirty healthy adult Wistar rats were equally randomized into Group A (sham-operation control), B (torsion/detorsion) and C (torsion/detorsion plus intraperitoneal injection of astragalus). The testicular torsion/detorsion model was established by the Turner method. All the rats were fed under the same condition for 7 days and sacrificed, and the torsional testes were harvested for the detection of germ cell apoptosis, glutathione activity and the level of malonic diethylaldehyde (MDA).

RESULTSThe apoptosis indexes (AI) of spermatogenic cells in the torsional testes were (5.82 +/- 1.21), (36.18 +/- 8.40) and (20.39 +/- 3.57) in Group A, B and C, significantly higher in Group B and C than in A (P < 0.05) and in Group B than in C (P < 0.05). Significant differences were observed in glutathione activity in the ipsilateral testes among Group A (48.03 +/- 2.01), B (30.93 +/- 1.25), C (38.44 +/- 1.06) U/mg (P< 0.05), as well as in the level of MDA, (1.43 +/- 0.17), (3.98 +/- 0.36), (2.57 +/- 0.53) nmol/ml, among the three groups (P < 0.05).

CONCLUSIONAstragalus could significantly reduce the apoptosis of spermatogenic cells, decrease the level of lipid peroxidation and protect glutathione activity in the torsional testis.

Animals ; Apoptosis ; Astragalus Plant ; Disease Models, Animal ; Lipid Peroxidation ; Male ; Phytotherapy ; Rats ; Rats, Wistar ; Spermatic Cord Torsion ; drug therapy