'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 observe the curative effects of monosialotetrahexosyl ganglioside(GM1)on neonates with moderate and severe hypoxic-ischemic encephalopathy(HIE).Methods Eighty-six neonates with HIE were randomly divided into GM1 treatment group and control group.The control group(42 cases)were received routine treatment(including cerebrolysin and citicoline);the treatment group(44 cases)were given GM1 on the basis of routine treatment as early as possible(within 6 hours after birth).Brain CT,neonatal behavioral neurological assessment(NBNA)and children's development center of China(CDCC)at 12 months after birth were proformed in both groups.Results Brain CT,NBNA and CDCC markers in treatment group were better than those in control group(Pa

Objective To explore the association between the infection of human cytomegalovirus(HCMV),herpes simplex virus typeⅠ(HSV-Ⅰ),HSV-Ⅱ,toxoplasma(TOX) and serum hepatitis B virus(HBV)these 5 pathogens and low body weight and pneumonia,and explore the clinical value of nested polymerase chain reaction (PCR) examining newborns infected with pathogens.Methods Forty-six newborn infants with low weight and 66 newborn infants with pneumonia were selected.And 1 mL pripheral blood of every newborn infant was drawn.Classic phenol-chloroform-isoamyl alcohol-protease digested,after neonatal serum extraction of DNA in peripheral blood through 2 pairs of pri-mers,the outer primer amplified larger DNA fragments and the inner primer amplified small fragments,in the amplified products.HCMV,HSV-Ⅰ,HSV-Ⅱ,TOX and HBV of the viral DNA in highly conservative district to design primer respectively and amplify its viral DNA,nested PCR was used to detect of these pathogens DNA in infants of low body weight and pneumonia,and to detect positive rate of infection.Screening for birth defects in infants in these virus infection.SPSS 10.0 software was used to analyze the relationship between infection of 5 pathogens.Results The infective rate of HCMV in 46 infants with low body quality was 91.3%,the infective rate of HSV-Ⅰwas 8.7%,the infective rate of HSV-Ⅱwas 15.2%,the infective rate of TOX was 8.7%,and the infective rate of HBV was 15.2%.Among 66 infants with pneumonia,the infective rate of HCMV was 83.3%,the infective rate of HSV-Ⅰwas 6.1%,the infective rate of HSV-Ⅱwas 16.7%,the infective rate of TOX was 6.1%,and the infective rate of HBV was 7.6%.The infective rate of HCMV was higher than that of other 4 pathogens,these infection rates were different statistically in these 5 kinds of pathogens(Pa=0).Conclusions Five kinds of pathogens both low pathosens screening is necessary newborns infants with low body weight and pneumonia,and for the early diagnosis and prevention of these pathogens.

Abstract?AIM: To investigate the influence of propylene glycol mannite sulfate ( PGMS ) on the expression of tumor necrosis factor -α( TNF-α) and interleukin-1β( IL-1β) , in diabetic retinopathy by a rat model, to study the mechanism of PGMS against diabetic retinopathy, and provide a reliable theoretical and experimental evidence for the PGMS to be applied to clinical prevention and treatment of diabetic retinopathy.?METHODS: Male Wistar rats were randomized into 4 groups, normal control group, diabetic control group and PGMS in group, the PGMS in groups included the doses of 50mg/kg and 100mg/kg. 1% streptozotocin ( STZ) of 60 mg/kg was intraperitoneally injected in rats to establish the diabetic models. The PGMS with the doses of 50mg/kg and 100mg/kg were used to gavage in different groups of models for 12wk.Twelve weeks later, the animals were sacrificed and retinas were isolated. The aqueous humors and serums were taken, expressions of TNF-αand IL-1βprotein in retinas, aqueous humors and serums were detected by enzyme-linked immunosorbent assay ( ELISA) , respectively.The location and the expression of TNF-αand IL-1βprotein in retina tissue was detected by immunohistochemistry.?RESULTS: Twelve weeks after the use of PGMS, the level of blood glucose was not changed.ELISA showed that the expression of TNF-αand IL-1βprotein in serum and retina was significantly increased in diabetic control group than in normal control group(P<0.05), but in the groups which PGMS was given reduced, lower than those in diabetes mellitus( DM) group, especially as the concentration of PGMS increased ( P<0.05 ).But the levels of aqueous humor's TNF-αand IL-1βproteins in PGMS group were not reduced.Immunohistochemistry showed that the TNF -α protein was almost not expressed in normal control group. But the TNF-αprotein was highly expressed in diabetic control group. The expression mainly located in the ganglion cell layer, the inner plexiform layer, outer plexiform layer and pigment epithelium. The TNF-αprotein was weakly expressed at the group of 50mg/kg PGMS, the TNF-αprotein was almost not expressed at the group of 100mg/kg PGMS.When the normal control group was detected, the IL-1βprotein was weakly expressed in the outer plexiform layer.But the IL-1βprotein was also highly expressed in diabetic control group.The expression mainly located in the inner plexiform layer, outer plexiform layer and pigment epithelium. The IL -1βprotein was weakly expressed at the group of 50mg/kg and 100mg/kg PGMS.?CONCLUSION:PGMS can treat the diabetic retinopathy by downregulating the expressions of TNF-αand IL-1βin early diabetic retinopathy.PGMS maybe have a good control effect on early diabetic retinopathy.

To analyze the causes and treatments of high intraocular pressure ( > 21mmHg ) of angle - closure glaucoma underwent compound trabeculectomy 1mo after surgery.
●METHODS: This was a retrospective study of our hospital, from March 2010 to March 2013. Thirty-four (38 eyes) of angle-closure glaucoma patients were collected, who underwent compound trabeculectomy with high intraocular pressure ( > 21mmHg) 1mo after operation. We analyzed the causes and summarized the treatments.
●RESULTS:The causes which lead to early postoperative high intraocular pressure included malignant glaucoma (9 eyes of 8 cases), blood clot and connective tissue block under the scleral flap (15 eyes of 13 cases), hyphema after surgery(5 eyes of 5 cases), sclera flap incision was incarcerated with iris tissue ( 3 eyes of 3 cases ), preoperative high intraocular pressure for a long time(5 eyes of 4 cases), 1 eye of 1 case for unknown reason. After proper treatments, intraocular pressures of all patients were bellowed 21mmHg.
● CONCLUSlON: Early postoperative high intraocular pressure of angle - closure glaucoma underwent compound trabeculectomy is caused by various factors, and the early prevention and timely treatment are key points of a successful operation.

Objective To analyze the relationships between the drinking water fluoride and bone mineral density (BMD), and serum osteocalcin (BGP) and to explore the BMD and serum BGP as significant early screening biomarkers for fluorosis especially for early bone damage in endemic fluorosis areas. Methods Wamiao (severe endemic fluorosis area, as fluoride exposed group) and Xinhuai (non endemic fluorosis area, as control group) Village were selected in 2006. One hundred and fouty-six objects were chosen from 2 villages (103 in Wamiao, 43 in Xinhuai). The sex, age, body height, body weight, drinking water fluoride in each object's household well, BMD, and serum BGP were investigated, and the dose-response relationships were analyzed between the drinking water fluoride and BMD, and serum BGP. CurveExpert 1.3 Software was used to fit the dose-response relationships between the rate of abnormal BMD, the rate of abnormal serum BGP, and the drinking water fluoride. Results The levels of drinking water fluoride in males' and females' families in fluoride exposed group were [(2.38±0.68), (2.62±0.91 )mg/L] significant higher than that in control group [(0.35±0.08), (0.36±0.07)mg/L], the difference being statistically significant(t values were 14.27 and 11.08,and P<0.01, respectively). BMD in males in fluoride exposed group [(0.78±0.07)g/cm2] was significant lower than that in control group[(0.83±0.08)g/cm2], the difference being statistically significant (t=2.37,P<0.05). Serum BGP in males and females in fluoride exposed group [(4.17±0.67), (4.11±0.57) μg/L] were significant higher than that in control group [(1.48±0.40), (1.44±0.39)μg/L], the difference being statistically significant (t values were 17.64 and 19.40, and P<0.01, respectively]. BMD in the group with drinking water fluoride≥2.92 mg/L[(0.66±0.15 )g/cm2] was significant lower than that in the group with drinking water fluoride<0.42 mg/L [(0.76±0.12)g/cm2], the difference being statistically significant (P<0.01). The levels of serum BGP in the groups with the drinking water 0.42-,2.05-, ≥.92 mg/L[(3.83±1.07), (4.22±0.72), (3.99±0.63) μg/L] were significant higher than that in the group with the drinking water<0.42 mg/L [(1.44±0.37) μg/L], the difference being statistically significant (P<0.01). The equation for the dose-response relationship between the drinking water fluoride and the rate of abnormal BMD was y=(0.284-0.058x)-1.260, r=0.999 94; and y=100.05/(1+78.62e-4.5x), r=0.999 99 for the drinking water fluoride and the rate of abnormal serum BGP. Conclusions There were significant dose-response relationships between drinking water fluoride and BMD and serum BGP. It indicated that BMD and BGP might be considered as early screening biomarkers for endemic fluorosis, especially for the bone damage.

alphaB-crystallin is the structural protein of vertebrate lens, which is widely expressed in non-lens tissue. As one of the heat shock protein family members, alphaB-crystallin possesses biological properties of molecular chaperones and anti-apoptotic effects. Multi-factor injuries, such as retinopathy, inflammation and nervous system diseases, have a closely relationship with alphaB-crystallin. This paper reviews the research progress of the expression and mechanism of alphaB-crystallin in retina and extraocular tissues and organs.
Crystallins ; Gene Expression Regulation, Developmental ; Heat-Shock Proteins/metabolism* ; Humans ; Lens, Crystalline ; Retina ; alpha-Crystallin B Chain/metabolism*

OBJECTIVE: To compare the correlation between contrast vision (LV) and sweep visual evoked potential acuity (SVEP-A) among people with emmetropia, mild myopia, and moderate myopia. METHODS: The CV and SVEP-A were tested individually in 96 eyes from healthy young volunteers, including 37 eyes of emmetropia, 27 eyes of mild myopia, and 32 eyes of moderate myopia. The statistic analysis was done by ANOVA analysis and rank sum test. RESULTS: (1) With the decrease of contrast, CV and SVEP-A decreased in every group. (2) At 100% contrast, the difference of CV between emmetropia and mild myopia had statistical significance (P<0.05). At 100%, 25% and 10% contrast, the difference of CV between emmetropia and moderate myopia had statistical significance (P<0.05). (3) In the same group, the difference of 100% and 25% contrast had statistical significance (P < 0.05). So was between 100% and 10% contrast. (4) At 100% and 10% contrast, the difference of CV and SVEP-A had statistical significance (P < 0.05). CONCLUSION The CV of myopia relates to many factors including ametropia and fundus lesions. The correction of ametropia is important to the values of CV and SVEP-A.
Evoked Potentials, Visual/physiology* ; Eye ; Fundus Oculi ; Humans ; Myopia/physiopathology* ; Neurologic Examination ; Severity of Illness Index ; Vision Tests/instrumentation* ; Visual Acuity/physiology*

OBJECTIV: e To find the correlation between real best corrected visual acuity (BCVA) and testing results of microperimetry and visual evoked potential (VEP) and to explore a new method in recording BCVA in macular disease. METHODS: Sixty-two patients with macular disease (macular disease group, 62 eyes) and eighteen healthy volunteers (control group, 36 eyes) had BCVA, microperimetry and VEP recorded. RESULTS: (1) By microperimetry, the values of retinal mean sensitivity and fixation percentage in macular disease group were lower than that in control group. The bicurve ellipse area in macular disease group was higher than that in control group. By VEP, P100 amplitude under 0.5 cpd and 2 cpd in macular disease group were significantly higher than that in control group and the latency was prolonged (P < 0.05). (2) In macular disease group, BCVA had significant positive correlation with retinal mean sensitivity, bicurve ellipse area, macular central 2 degrees and 4 degrees fixation percentage, respectively (P < 0.05). There was a significant correlation between retinal mean sensitivity and P100 amplitude (P < 0.05). (3) Multiple linear regression equation was y = 0.053 x1+0.008 x3+3.897 (y was BCVA, while x1 was retinal mean sensitivity and x3 was P100 amplitude under 2 cpd). CONCLUSION Combined use of microperimetry and VEP is useful in the assessment of BCVA in macular disease.
Case-Control Studies ; Evoked Potentials, Visual/physiology* ; Eye ; Humans ; Macula Lutea/physiopathology* ; Retina ; Retinal Diseases/pathology* ; Tomography, Optical Coherence ; Visual Acuity/physiology* ; Visual Field Tests/methods*

OBJECTIVE: To study the characters of oscillatory potentials (OPs) of electroretinogram (ERG) after methanol intoxication in rats. METHOD: The SD rat models of methanol intoxication were established and divided into control group, 3-day intoxication group, 7-day intoxication group. The changes of OPs of ERG were recorded in a dark room. RESULTS: The total amplitudes of 3-day and 7-day intoxication groups decreased approximately 50% compared with that of the control group, while the schedule delayed approximately 16% and 61%, respectively. CONCLUSION The characters of methanol intoxication in rats included delay in schedule and decline in the total amplitude of OPs.
Animals ; Electroretinography ; Methanol/poisoning* ; Rats ; Retina/physiopathology*