A novel bio-active adhesive monomer induces odontoblast differentiation: a comparative study

AIM

To evaluate the in vitro effect of the novel adhesive monomer CMET, a calcium salt of 4-methacryloxyethyl trimellitate (4-MET), on the proliferation, mineralization and differentiation of odontoblast-like cells, comparing with 4-MET, calcium hydroxide (CH) and mineral trioxide aggregate (MTA).

METHODOLOGY

Rat odontoblast-like MDPC-23 cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 5% foetal bovine serum. The powder of four tested materials (CMET, 4-MET, CH and MTA) was first dissolved in distilled water (dH₂O) and then was diluted by DMEM to yield final concentrations. Solvent (dH₂O) was used as a control. Cell viability was assessed using CCK-8 assay. Real-time RT-PCR was used to quantify the mRNA expression of odontogenic markers, cytokines and integrins. Mineralization inducing capacity was evaluated by alkaline phosphatase (ALPase) activity and alizarin red S staining. Statistical analyses were performed using one-way anova and post hoc Tukey's HSD test, with the significance level at 1%.

RESULTS

Cell viability was significantly greater in the CMET- (83 to 828 mmol L^-1), CH- and MTA-treated (low concentrations) groups than that in the control group (P < 0.01). Higher concentrations of each material decreased the viable cells to different extents (P < 0.01). CMET treatment augmented the expression of several integrin subunits and exhibited the highest mRNA expression levels of odontogenic markers among all groups (P < 0.01). CH and MTA treatment caused significantly greater upregulation of pro-inflammatory cytokines expression than the other groups (P < 0.01). The calcific deposition of MDPC-23 cells was dose-dependently accelerated by the addition of CMET (P < 0.01); the enhancement of mineralization was also found in the fresh prepared CH and MTA treatments. Besides, CMET showed consistency in mineralization induction after 8 weeks storage. Exposure to SB202190, a specific p38 mitogen-activated protein kinases inhibitor, significantly decreased the ALPase activity as well as the mineral deposition which was enhanced by CMET treatment (P < 0.01).

CONCLUSIONS

The novel bio-active monomer had the lowest cytotoxicity among all groups and it induced the proliferation, mineralization and differentiation of odontoblast-like cells under appropriate concentrations. This adhesive monomer possesses excellent biocompatibility and hence exhibits great potential in dentine regeneration.

[Clinical analyses of 24 patients with primary pulmonary NK/T-cell lymphoma]

Objective: To explore the clinical characteristics, the best treatment and prognostic factors of primary pulmonary NK/T-cell lymphoma. Methods: A total of 24 cases with primary pulmonary NK/T-cell lymphoma from April 2011 to May 2019 were analyzed retrospectively. Survival analysis was performed using the Kaplan-Meier method and groups were compared using the log-rank test. Multivariate analysis using Cox proportional hazard regression model was conducted to confirm independent prognostic factors for overall survival (OS) and progression-free survival (PFS) . Results: ①The cohort of 24 patients included 16 male and 8 female with a median age of 49 years (range, 4-76 years) old. ②Most patients initially presented with a fever (66.7%) , cough and dyspnea. Chest imaging manifestations were primarily unilateral (45.8%) or bilateral (54.2%) pulmonary consolidation, nodules or mass. ③20 patients received chemotherapy, radiotherapy or hematopoietic stem cell transplantation, the rest 4 cases palliative treatment. Median OS was 9.5 months (range, 0.1-26.0 months) . The estimated 1-year OS rate was 45.8%. Overall response rate of patients treated with asparaginase-based regimen was 88.2%. ④In univariate survival analysis, age≤60 was prognostic for longer OS and PFS, compared with age>60 (P=0.002 and 0.004, respectively) ; ECOG≤2 was prognostic for longer OS and PFS, compared with ECOG>2 (P=0.042 and 0.004, respectively) . In multivariate survival analysis, age>60 and ECOG>2 were significantly correlated with inferior OS and PFS (OS: P=0.024 and 0.024, respectively; PFS: P=0.035 and 0.024, respectively) . Conclusions: Primary pulmonary NK/T-cell lymphoma was a rare disease with poor prognosis. Asparaginase-based regimens appeared to be effective. Age and ECOG served as independent prognostic factors for primary pulmonary NK/T-cell lymphoma patients.

[14-3-3ζ protein mediates gemcitabine resistance in NK/T-cell lymphoma]

Objective: To explore the molecular mechanisms of 14-3-3ζ in gemcitabine resistance in extranodal NK/T-cell lymphoma, nasal type (ENKTL) . Methods: The effects of cell proliferation and invasion were detected by cell counting kit-8 (CCK-8) assay and transwell assay. YTS cells were exposed to gradually increased concentrations of gemcitabine to establish gemcitabine-resistant YTS cells (YTS-gem) in vitro. 14-3-3ζ specific siRNA lentiviral vector was transfected into YTS and YTS-gem cells to downregulate 14-3-3ζ expression, and stable transfected cell clones were screened. The protein expression was determined by Western blot. Results: ①14-3-3ζ expression was significantly up-regulated in gemcitabine resistant YTS-gem cells, comparing with that of YTS cells (P<0.05) . ②The results of CCK-8 and transwell assay showed that downregulation of 14-3-3ζ significantly reduced the cell proliferation and invasion abilities (P<0.05) . ③Downregulation of 14-3-3ζ could restore gemcitabine sensitivity in gemcitabine resistant YTS-gem cells (P<0.05) . ④Western blotting results showed that knockdown of 14-3-3ζ significantly upregulated pro-apoptotic Bax, and downregulated anti-apoptotic Bcl-2, Caspase-3, cleaved caspase-3, Cyclin D1 in gemcitabine-resistant YTS-gem cells (P<0.05) . There was no significant difference in p53 ang P-gp expression levels. Conclusions: 14-3-3ζ was upregulated in gemcitabine resistant YTS cells. Overexpression of 14-3-3ζ promoted cell proliferation and enhanced cell migration. 14-3-3ζ contributed to gemcitabine resistance to ENKTL through anti-apoptosis.

[PD-L1 expression is related with prognosis of small cell lung cancer]

Objective: To explore the correlation between programmed death ligand 1 (PD-L1) expression and clinicopathological features and prognosis of small cell lung cancer (SCLC). Methods: The clinicopathological data of 64 patients with small cell lung cancer from January 2013 to December 2016 in the First Affiliated Hospital of Zhengzhou University were retrospectively analyzed in this study. The correlation between PD-L1 expression and the clinicopathological features and prognosis of SCLC was analyzed. Results: Immunohistochemical staining revealed that PD-L1 expression was observed in 60.9% (39/64) of patients with small cell lung cancer. PD-L1 expression was significantly related to stages (P<0.001). Univariate analysis showed that the median overall survival of PD-L1 negative group was longer than PD-L1 positive group (16 months vs 14 months, P<0.001). Median progression-free survival of PD-L1 negative group was longer than PD-L1 positive group(15 months vs 9 months, P<0.000 1). In multivariate analysis, PD-L1 positive was significantly correlated with inferior progression-free survival (P=0.006). Conclusions: PD-L1 expression rate was high in small cell lung cancer. PD-L1 expression was an independent predictor for poor prognosis of patients with small cell lung cancer.

Increasing thermal stability of glutamate decarboxylase from Escherichia. coli by site-directed saturation mutagenesis and its application in GABA production

Gamma-amino butyric acid (GABA) is an important bio-product used in pharmaceuticals, functional foods, and a precursor of the biodegradable plastic polyamide 4 (Nylon 4). Glutamate decarboxylase B (GadB) from Escherichia. coli is a highly active biocatalyst that can convert l-glutamate to GABA. However, its practical application is limited by the poor thermostability and only active under acidic conditions of GadB. In this study, we performed site-directed saturation mutagenesis of the N-terminal residues of GadB from Escherichia coli to improve its thermostability. A triple mutant (M6, Gln5Ile/Val6Asp/Thr7Gln) showed higher thermostability, with a 5.6 times (560%) increase in half-life value at 45 °C, 8.7 °C rise in melting temperature (Tm) and a 14.3 °C rise in the temperature at which 50% of the initial activity remained after 15 min incubation (T¹⁵₅₀), compared to wild-type enzyme. Protein 3D structure analysis showed that the induced new hydrogen bonds in the same polypeptide chain or between polypeptide chains in E. coli GadB homo-hexamer may be responsible for the improved thermostability. Increased thermostability contributed to increased GABA conversion ability. After 12 h conversion of 3 mol/L l-glutamate, GABA produced and mole conversion rate catalyzed by M6 whole cells was 297 g/L and 95%, respectively, while those by wild-type GAD was 273.5 g/L and 86.2%, respectively.

[Efficacy and tolerance of Memantine monotherapy and combination therapy with Reinhartdt And Sea Cucumber Capsule on agitation in moderate to severe Alzheimer disease]

Objective: To explore the efficacy and tolerance of Memantine combined Reinhartdt And Sea Cucumber Capsule (R.S.C) on treating agitation in patients with moderate-severe Alzheimer disease (AD). Methods: One hundred and fifty-eight moderate-sever AD patients from Sep.2013 to Sep.2014 in Zhejiang Provincial People's Hospital were randomly divided into two groups: group of Memantine combined R. S.C and group of single Memantine. Then Mini-Mental Sate Examination (MMSE) and Neuropsychiatric Inventory (NPI) were used to evaluate cognition symptom, behavioral and psychological symptoms of dementia (BPSD) and agitation symptom at the baseline and the end of 24 weeks.The Treatment Emergent Symptom Scale (TESS) was used to assess adverse reaction and tolerance.At last, the data was analyzed by chi-square test, t-test and covariance test. Result: At the terminal of experience, the total NPI scores and agitation factor decreased markedly in both of the two groups (P<0.05). Among the patients who had agitation symptom at the baseline, the total NPI scores and agitation factor (18±5, 3.7±2.6) in group of Memantine combined R. S.C were notably lower than those in the group of single Memantine (21±6, 5.3±2.5) (P<0.05). The incidence of adverse reaction between the two groups had no significant difference (combined treatment group was 27.7%, single treatment group was 23.2%). One patient dropped out because of skin allergy, and most adverse reactions were tolerant. Conclusions: Both two groups are effective in agitation and BPSD, and Memantine combined R. S.C is better than single treatment.R.S.C dose not aggravate adverse reaction and can be well tolerated.

Experimental test and life estimation of the OLED at normal working stress based on the luminance degradation model

In order to accurately acquire the life time information for the organic light emitting diode (OLED), an experiment based on the normal stress life test was carried out to gain the data for the luminance degradation tests. The luminance degradation model of OLED was established based on the Weibull function and the least square method. Combined with luminance degradation data, Weibull parameters were estimated, the qualitative and the quantitative relationship between the initial luminance and the OLED life was obtained, and the life estimation of the product was achieved. Numerical results show that the test scheme is feasible, the luminance degradation model proves to be reliable for the OLED life estimation, and the fitting accuracy is very high by comparison with the test data fluctuation. Moreover, the real life time of the OLED is measured, which can verify the validity of the assumptions used in accelerated life test methods and provide manufacturers and customers with significant guidelines.