Enhanced Bonding to Caries-Affected Dentin Using an Isocyanate-Based Primer

Dental caries is the most common oral disease and the most common cause of resin restorations. In minimally invasive dentistry, the principle behind cavity preparation is to remove external caries-infected dentin (CID) and preserve internal caries-affected dentin (CAD) and sound dentin (SD). The cavity floor is mainly composed of CAD, but the poor bonding performance of CAD has become a widespread concern. This study evaluated the performance of a new collagen-reactive monomer (ITCM) used as a primer to improve the bonding performance of CAD. The experimental specimens were grouped as follows: SD, CAD, and ITCM-pretreated CAD (CAD-ITCM). Dentin slices were obtained for attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis. The bonded samples were subjected to microtensile bond strength analysis after 24 h of water storage or aging by thermocycling, and the bonding interface quality was evaluated by nanoleakage assessment, interfacial nanoindentation testing, and in situ zymography. Cytotoxicity experiments with ITCM were performed. ATR-FTIR showed that the isocyanate groups in ITCM can covalently bind and form hydrogen bonds with the collagen in CAD to mediate chemical bonding. ITCM pretreatment significantly improved the bond strength of CAD (P < 0.05), reduced interfacial nanoleakage, improved the sealing of the bonding interface, enhanced the homogeneity of the hybrid layer, and inhibited matrix metalloproteinase activity. In addition, ITCM presented acceptable biocompatibility for dental restorative application. Taken together, this study reported the application of ITCM to induce collagen-based chemical bonding in the CAD bonding system, which fills the gap in strategies to improve the bonding performance of CAD immediately and after aging and has important clinical application prospects.

A novel dentin bonding scheme based on extrafibrillar demineralization combined with covalent adhesion using a dry-bonding technique

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extrafibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique. However, adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space, and the excess water that is introduced by the wet-bonding technique remains at the bonding interface. This imperfectly bonded interface is inclined to hydrolytic degradation, severely jeopardizing the longevity of bonded clinical restorations. The present study introduces a dentin bonding scheme based on a dry-bonding technique, combined with the use of extrafibrillar demineralization and a collagen-reactive monomer (CRM)-based adhesive (CBA). Selective extrafibrillar demineralization was achieved using 1-wt% high-molecular weight (MW) carboxymethyl chitosan (CMCS) within a clinically acceptable timeframe to create a less aggressive bonding substance for dentin bonding due to its selectively extrafibrillar demineralization capacity. CMCS demineralization decreased the activation of in situ collagenase, improved the shrinking resistance of demineralized collagen, and thus provided stronger and more durable bonding than traditional phosphoric acid etching. The new dentin bonding scheme that contained CMCS and CBA and used a dry-bonding technique achieved an encouraging dentin bonding strength and durability with low technical sensitivity. This bonding scheme can be used to improve the stability of the resin-dentin interface and foster the longevity of bonded clinical restorations.

Evaluation of a Collagen-Reactive Monomer with Advanced Bonding Durability

This study evaluated the use of a new collagen-reactive monomer (CRM), isocyanate-terminated urethane methacrylate precursor, which has covalent affinity to dental collagen, in the formation of dentin-resin bonds and compared it with 2 other dental adhesives. Dentin specimens were bonded with either the CRM-based adhesive (CBA), One-Step (OS; Bisco, Inc.), or a negative adhesive (NA) control and subjected to 24-h storage in water, thermocycling to simulate 1-y clinical function, or a matrix metalloproteinase-mediated aging process. We tested the microtensile bond strength (µTBS), characterized the bonding interface with an atomic force microscope, conducted micro-Raman analysis, and performed leakage tests and in situ zymography. CBA and OS exhibited comparable bonding strength after 24 h (P > 0.05); however, there was a sharp decrease in µTBS after aging for all except CBA (P < 0.001). Raman spectra results indicated increased collagen crosslinking and chemical reaction between the adhesive and collagen in the CBA group. CBA achieved high-quality hybridization with collagen, improving mechanical properties and integrity, and decreased the enzyme-mediated degradation of the bonding interface by inhibiting collagenolytic activity. With the promising bonding durability of coapplied CBA, CRM may be the first dental adhesive to provide strong and long-lasting resin-dental collagen bonding without the additional conditioning step. The use of CBA results in high-quality hybrid layers that protect the resin-dentin interface from harmful biological and chemical activities commonly occurring in the oral environment.

[Economic evaluation on strategy for preventing mother-to-child transmission of hepatitis B in Zhejiang Province]

Objective: To evaluate the cost-benefit and cost-effectiveness of current strategy for preventing mother-to-child transmission (PMTCT) of hepatitis B virus. Methods: A decision tree model with the Markov process was developed and simulated over the lifetime of a birth cohort in Zhejiang Province in 2016. The current PMTCT strategy was compared with universal vaccination and non-vaccination. Costs were assessed from social perspective. Benefits were the savings from reduced costs associated with disease and effectiveness were measured by quality-adjusted of life-years (QALY) gained. The net present value (NPV), cost-benefit ratio (BCR) and incremental cost-effectiveness ratio (ICER) were calculated. Univariate and Probabilistic Sensitivity Analyses (PSA) were performed to assess parameter uncertainties. The parameters of costs and utilities value of hepatitis B-related disease came from the results of the field survey, which were obtained by face-to-face questionnaire survey combined with inpatient medical records, including eight county and municipal hospitals in Jinhua, Jiaxing and Taizhou. A total of 626 outpatients and 523 inpatient patients were investigated. The annual total costs of infection was calculated by combining the costs of outpatient and inpatient. Results: The PMTCT strategy showed a net-gain as 38 323.78 CNY per person, with BCR as 21.10, which was higher than 36 357.80 CNY per person and 13.58 respectively of universal vaccination. Compared with universal vaccination, the PMTCT strategy would save 2 787.07 CNY per additional QALY gained for every person, indicating that PMTCT would be cost-saving. The most important parameters that could affect BCR and ICER were the vaccine coverage rate and costs of hepatitis B related diseases respectively. The PSA showed the PMTCT strategy was preferable as it would gain more QALY and save costs. Conclusions: The PMTCT strategy appeared as highly cost-beneficial and highly cost-effective. High vaccination rate was a key factor of high economic value.

Conditioned Medium from Human Umbilical Vein Endothelial Cells Promotes Proliferation, Migration, Invasion and Angiogenesis of Adipose Derived Stem Cells

Preeclampsia (PE) is a pregnancy-specific hypertensive complication, closely related to endothelial dysfunction. Adipose derived stem cells (ADSCs) have the capacity to differentiate into endothelial cells for vascular repair. Therefore, we hypothesized that induced endothelial differentiation of ADSCs might hold great potential for the treatment of PE. In this study, the primary ADSCs and human umbilical vein endothelial cells (HUVECs) were isolated by the collagenase digestion method. The supernatant of HUVECs was collected from the first generation of cells. Then, ADSCs were divided into two groups: ADSCs alone group and induced ADSCs (iADSCs) group. In iADSCs group, ADSCs were induced by HUVECs conditioned medium and ADSCs special culture medium at a ratio of 1:1 over a two-week period. In order to identify the endothelial characteristics of iADSCs, CD31 and CD34 were examined by flow cytometry. The proliferation, migration, invasion and angiogenesis assays were employed to compare the bioactivity of iADSCs and ADSCs. Furthermore, The levels of angiogenic related factors including vascular endothelial growth factor (VEGF) and placenta growth factor (P1GF) were detected by RT-PCR and Western blotting. Results showed conditioned medium from HUVECs promoted ADSCs proliferation, migration, invasion and angiogenesis. In addition, the levels of VEGF and P1GF were significantly enhanced in iADSCs group. This study uncovered the iADSCs application potential in the therapy and intervention of PE.

Identification of natural recombinants derived from PCV2a and PCV2b

Porcine circovirus type 2 (PCV2) is considered to be the main pathogen in PC-associated diseases, and significantly affects the global pig-producing industry. PCV2 continuously evolves by point mutations and genome recombinations. In the present study, we aimed to further identify recombinant PCV2 strains. We used polymerase chain reaction to detect PCV2 in the carcasses of pigs with suspected infections from different regions of Guangdong Province in China. DNA was extracted from samples with confirmed infection and full- genome amplification, sequencing, phylogenetic tree construction, gene recombination detection, and sequence alignment were performed in gene recombination analysis. Our results show that recombination occurred between the strains SHC (DQ104421) and ZhuJi2003 (AY579893). The recombination resulted in three recombinants: GD003 (KM503044), GD005 (KM487708), and GD008 (KM487709). Further analyses revealed that these novel recombinants appeared to result from recombination between the PCV2a and PCV2b strains, with crossover regions located in ORF2. This study was a comprehensive analysis that used several different methods, which demonstrated that a cluster of PCV2 strains resulted from the same type of inter-genotypic recombination pattern, with a breakpoint in the structural protein coding region. The results of our study provide both information on the recombination mechanism and disease pathogenesis and useful data for the prevention of PCV2 in the swine industry.

Pre-mRNA splicing and mRNA export linked by direct interactions between UAP56 and Aly

Recent studies indicate that splicing of pre-messenger RNA and export of mRNA are normally coupled in vivo. During splicing, the conserved mRNA export factor Aly is recruited to the spliced mRNA-protein complex (mRNP), which targets the mRNA for export. At present, it is not known how Aly is recruited to the spliced mRNP. Here we show that the conserved DEAD-box helicase UAP56, which functions during spliceosome assembly, interacts directly and highly specifically with Aly. Moreover, UAP56 is present together with Aly in the spliced mRNP. Significantly, excess UAP56 is a potent dominant negative inhibitor of mRNA export. Excess UAP56 also inhibits the recruitment of Aly to the spliced mRNP. Furthermore, a mutation in Aly that blocks its interaction with UAP56 prevents recruitment of Aly to the spliced mRNP. These data suggest that the splicing factor UAP56 functions in coupling the splicing and export machineries by recruiting Aly to the spliced mRNP.

Prognostic significance of combined conventional and immunocytochemical cytology for peritoneal washings in endometrial carcinoma

BACKGROUND

Noncancerous cells simulating adenocarcinoma cells may interfere with the analysis of peritoneal cytology (PC) in patients with endometrial carcinoma. Immunocytochemistry (ICC) may improve the diagnosis of PC.

METHODS

PC slides from 115 patients with endometrial carcinoma were reviewed. Suspicious or positive cell clusters were recovered with a cell transfer method and were subjected to ICC for MOC-31, cytokeratin 5/6, and p53. Conventional Papanicolaou staining and ICC results were compared directly on the same cells.

RESULTS

By combined conventional and immunocytochemical PC (CONV-ICC-PC), cytodiagnosis was positive in 18 of 115 patients (15.7%) and suspicious in 3 of 115 patients (2.6%). According to a multivariate Cox regression analysis of patients with tumors confined to the uterus that included grade, myometrial invasion, cervical involvement, and CONV-ICC-PC, only CONV-ICC-PC was an independent prognostic factor (P < 0.05). A multivariate analysis for all of the patients studied that compared CONV-ICC-PC with staging variables revealed that only peritoneal metastasis (P < 0.0001) and lymph node metastasis (P < 0.01) were independent prognostic factors. When peritoneal metastases were excluded, CONV-ICC-PC (P < 0.01) and lymph node metastasis (P < 0.0025) were the independent prognostic factors. By cell transfer and p53 immunostaining in samples from 14 patients with malignant cells in their peritoneal washings, no deaths occurred among 5 patients with negative p53, whereas 5 of 9 patients with positive p53 died of disease at the time of data analysis.

CONCLUSIONS

MOC-31 immunostaining improves the diagnosis of PC in endometrial carcinoma. Positive PC is an important prognostic factor for patients with endometrial carcinoma confined to the uterus. The p53 positive cells in PC have possible prognostic significance.

Comparative rates of elimination of some individual polychlorinated biphenyls from the blood of PCB-poisoned patients in Taiwan

In 1979, a mass outbreak of poisoning occurred in Central Taiwan due to the ingestion of rice-bran oil contaminated with polychlorinated biphenyls (PCBs). The major PCB isomers and congeners in the toxic rice oil and in the blood of PCB-poisoned patients were characterized by gas chromatography and gas chromatography/mass spectrometry using a highly efficient glass capillary column. The elimination of some major individual PCBs from blood of these patients was studied. The results indicate that tetra- and pentachlorobiphenyls with adjacent unsubstituted carbon atoms at meta-para positions are rapidly eliminated from the blood of patients, while PCBs with the same degree of chlorination but with adjacent unsubstituted carbon atoms at ortho-meta positions are eliminated more slowly. The results also indicate that most of the hexa- and heptachlorobiphenyls, with adjacent unsubstituted carbon atoms at ortho-meta positions of the biphenyl ring, are eliminated very slowly. Laboratory-animal studies have indicated that PCB excretion depends primarily on the rate of metabolism; therefore these differences in rates of elimination of PCBs should reflect the differences in their rates of metabolism.