Effects and mechanisms of fatty acid metabolism­mediated glycolysis regulated by betulinic acid­loaded nanoliposomes in colorectal cancer.

Although previous studies have demonstrated that triterpenoids, such as betulinic acid (BA), can inhibit tumor cell growth, their potential targets in colorectal cancer (CRC) metabolism have not been systematically investigated. In the present study, BA­loaded nanoliposomes (BA­NLs) were prepared, and their effects on CRC cell lines were evaluated. The aim of the present study was to determine the anticancer mechanisms of action of BA­NLs in fatty acid metabolism­mediated glycolysis, and investigate the role of key targets, such as acyl­CoA synthetase (ACSL), carnitine palmitoyltransferase (CPT) and acetyl CoA, in promoting glycolysis, which is activated by inducing hexokinase (HK), phosphofructokinase­1 (PFK­1), phosphoenolpyruvate (PEP) and pyruvate kinase (PK) expression. The results demonstrated that BA­NLs significantly suppressed the proliferation and glucose uptake of CRC cells by regulating potential glycolysis and fatty acid metabolism targets and pathways, which forms the basis of the anti­CRC function of BA­NLs. Moreover, the effects of BA­NLs were further validated by demonstrating that the key targets of HK2, PFK­1, PEP and PK isoenzyme M2 (PKM2) in glycolysis, and of ACSL1, CPT1a and PEP in fatty acid metabolism, were blocked by BA­NLs, which play key roles in the inhibition of glycolysis and fatty acid­mediated production of pyruvate and lactate. The results of the present study may provide a deeper understanding supporting the hypothesis that liposomal BA may regulate alternative metabolic pathways implicated in CRC adjuvant therapy.

[All-ceramic premolar guiding plate retains resin-bonded fixed partial dentures].

OBJECTIVE: This study aims to investigate the fracture resistance and short-term restorative effects of resin-bonded fixed partial dentures (RBFPDs) made from heat-pressed lithium-disilicate-based glass-ceramic (IPS e.max press) and zirconia ceramic (WIELAND) and retained by all-ceramic guiding plates when used to restore missing mandibular second premolars. METHODS: A total of 64 human mandibular first premolars and first molars were prepared as abutments, then were randomly divided into 4 groups (n=8): E0, heat-pressed ceramic RBFPDs, no cyclic loading; E1, heat-pressed ceramic RBFPDs exposed to 300 000 cycles of dynamic loading; W0, zirconia ceramic RBFPDs, no cyclic loading; and W1, zirconia ceramic RBFPDs exposed to 300 000 cycles of dynamic loading. Fracture strength was tested in a universal testing machine. RESULTS: The medians of fracture strength were 1 242.85 N±260.11 N (E0), 1 650.85 N±206.77 N (W0), 1 062.60 N±179.98 N (E1), and 1 167.61 N±265.50 N (W1). Statistical analysis showed that all the groups exhibited significantly higher fracture strength compared with the maximum bite force in the premolar region (360 N; P<0.001). The W0 group had significantly higher fracture strength than the E0 group (P<0.05). Meanwhile, no significant difference in fracture strength was observed between the E1 and W1 groups (P>0.05). Significant statistical differences were found between the zirconia ceramic groups (W0 and W1, P<0.05) but not between the glassceramic groups (E0 and E1, P>0.05) after dynamic loading. CONCLUSIONS: The RBFPDs retained by all-ceramic guiding plates exhibited promising fracture properties and optimal short-term restorative effects when used to restore missing mandibular second premolars.

[Minimal invasive microscopic tooth preparation based on endodontic, periodontal and functional health].

Tooth preparation is the primary and core operation technique for dental esthetic restoration treatment, due to its effect of providing restoration space, bonding interfaces and marginal lines for dental rehabilitation after tooth tissue reduction. The concept of microscopic minimal invasive dentistry put forward the issue of conducting high-quality tooth preparation, conserve tooth-structure, protect vital pulp and periodontal tissue simultaneously. This study reviewed the concepts, physiology background, design and minimal invasive microscopic tooth preparation, and in the meantime, individualized strategies and the two core elements of tooth preparation (quantity and shape) are listed.

[Study and preparation of a novel apatite-wollastonite bioactive glass-ceramic-calcium sulphate hemihydrate composite].

OBJECTIVE: To prepare a novel apatite-wollastonite bioactive glass-ceramic-calcium sulphate hemihydrate(AW-BGC-CSH) composite, to study its biocompatibility, and to provide experimental support for its further clinical application. METHODS: Samples of AW-BGC-CSH composite were prepared with different AW-BGC granules-CSH ratios (50%, 40%, 30%, 20%). Surface morphology, microstructure and mechanical features of the composite were measured. Osteoblasts were cultivated in vitro on the composite. Cell morphology, proliferation, and the alkaline phosphatase (ALP) activity of osteoblasts were examined to determine the biocompatibility of the composite. RESULTS: The composite showed a three-dimensional pored structure with communicated micropores under scanning electron microscopy (SEM). The plasticity of the composite could be maintained within 3 - 5 min. Its top solidification temperature was 36.4°C and the maximum compressive strength was 9.3 MPa. The osteoblasts adhered to the composite and grew well. At 1, 3, 5, 7 d after cultivated, the microprotein contents of the composite were (251 ± 12), (296 ± 31), (580 ± 13) and (571 ± 15) mg/L, and the ALP activity of the composite were (4.50 ± 0.68), (6.90 ± 0.27), (12.05 ± 0.28) and (11.86 ± 0.63) U/mg. The results of the ALP activity and microprotein contents in the experiment group were significantly higher than those in the control group (P < 0.05). CONCLUSIONS: The prepared AW-BGC-CSH composite has a three-dimensional pored structure, favourable plasticity, mechanical property and good biocompatibility.

[Effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys].

OBJECTIVE: To investigate the effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys in vitro. METHODS: The bond strength of coating-substrate interface sintered at different temperatures (300, 400, 500, 600 degrees C) was tested by scratching method. The Sol-Gel coating was analyzed by scanning electron microscope (SEM), and its corrosion resistance was assessed by a static immersion method. RESULTS: The bond strength of coating-substrate interface reaches the peak at 400 degrees C. The Sol -Gel coating can apparently inhibit the release of metal ions and improve the corrosion resistance of nickel-chromium alloy. CONCLUSION: Sol-Gel coating can evidently improve corrosion resistance of the nickel-chromium alloy, which has great potential in prospective clinical practice.

[Feasibility of permanent maxillary tooth removal using articaine anesthesia without palatal injection].

OBJECTIVE: This study was to test the feasibility of permanent maxillary tooth removal using articaine without a second palatal injection. METHODS: Of 104 patients, 38 patients had bilateral extraction and 66 patients had unilateral extraction of maxillary tooth. In the test group, 1.7 mL articaine with 1:100000 epinephrine was injected into the buccal vestibule of the tooth and the tooth were extracted after 5 minutes. In the control group, the patients were subjected to both palatal injection with 2% lidocaine hydrochloride and buccal injection with articaine. All patients completed visual analog scales (VAS) after extraction. RESULTS: The achievement ratio of permanent maxillary tooth anesthesia of test group was 96.2%. The achievement ratio of permanent maxillary tooth anesthesia of control group was 97.1%. There was no statistical significance between achievement ratio of test group and control group(P > 0.05). CONCLUSION: Permanent maxillary tooth removal without palatal injection is possible by articaine injection to the buccal vestibule of the tooth.

[Influence of manufacture technique on translucency and color of dental porcelain].

OBJECTIVE: To study the influence of manufacture technique on the translucency and color of dental porcelain. METHODS: Specimens were made of VITA VMK 95 dentin porcelain and enamel porcelain and divided into 3 groups: Sintering times group (1, 2, 4, 6, 8 and 10 times), sintering temperature group (910, 920, 930, 940 and 950 degrees C), sintering vacuum group (95, 65, 35 and 0 kPa). Transmittance, Y, dominant wavelength and saturation were measured by PR-650 spectra scan spectrocolorimeter. RESULTS: Transmittance of dentin porcelain increased after 6 times repeated sintering. Transmittance of enamel porcelain increased first after the second sintering, and then became decreasing when sintering more than 2 times. Transmittance of enamel porcelain deceased when sintering temperature was lower than standard. Decrease of sintering vacuum caused the transmittance of dentin and enamel porcelain decreased. The changing of value was coordinated with transmittance. Dominant wavelength and saturation had negative correlation with sintering times and temperature, and positive correlation with vacuum. CONCLUSION: Sintering times, temperature and vacuum all had prominent effects on the translucency and color of dental porcelain. Comparing with dentin porcelain, enamel porcelain was more sensitive with the modification of manufacture technique.

[Comparison of translucency between enamel, dentin and Vita veneer porcelain].

PURPOSE: To compare the translucency between enamel, dentin and dental porcelain. METHODS: 32 newly extracted vital human central incisors were collected and cut into 0.8mm enamel slices and 1.0 mm dentin slices. 1.0 mm dental porcelain specimen were made with different Vita veneer porcelain, EN1, EN2, T4, Window, A1, A2, A3, A3.5, A4, B2, C2, D2, 3 samples for each kind. The transmittance and reflectance of tooth slices and porcelain specimen were measured by PR-650 spectra scan spectrocolorimeter. The transmittance coefficients were also calculated. The 95% confidence interval was obtained by SPSS 12.0 software package. SNK method was used to compare the transmittance coefficients of different dentin porcelains. RESULTS: The transmittance coefficient of tooth enamel ranged from 0.0817 mm(-1) to 0.1009 mm(-1), which was higher than that of two kinds of enamel porcelain (0.0507 mm(-1) for EN1 and 0.0408 mm(-1) for EN2). The transmittance coefficient of dentin (0.0418-0.0482 mm(-1)) was also higher than that of dentin porcelain (0.016-0.027 mm(-1)). The transmittance coefficient of dentin porcelain decreased with the increasing of chroma (P<0.05). CONCLUSIONS: Prominent difference exists between translucency of tooth tissue and dental porcelain, especially between enamel and enamel porcelain.

[The effect of cryotreat on tensile properties of medium melting-point and high melting-point castable alloy].

OBJECTIVE: To introduce cryotreat technique into prosthetic dentistry by testing the tensile properties of CW-H Co-Cr-Mo cast alloy before and after cryotreat and to observe the image changes by SEM to study the mechanism that changes the tensile properties of the alloy. METHODS: 15 CW-H cast alloy were divided into 3 groups, i.e. control group (G1), cryotreated group (G2) and cryotreated plus post-cryogenic treated group (G3). The gauge test technique was employed to test the modulus of elasticity. Then the strength and percentage elongation (PE) were tested. SEM images were used to analyze the mechanism that improved the tension properties of the alloy. RESULTS: For CW-H alloy the strength and the modulus of elasticity of both G2 and G3 were effectively increased but PE effectively decreased than G1. There was no effectively difference between G2 and G3, but G3 was larger than G2. SEM images of G2 and G3 showed that secondary-carbonide separated out all over the alloy. CONCLUSION: The results obtained above suggest that cryotreat is an effective method in enhancing tensile properties of CW-H Co-Cr-Mo cast alloy.