Polymorphisms in the DC-SIGN gene and their association with the severity of hand, foot, and mouth disease caused by enterovirus 71.

Severe hand, foot, and mouth disease (HFMD) caused by enterovirus 71 (EV71) infection is associated with high mortality and disability. DC-SIGN, a receptor for EV71, is widely distributed in dendritic cells and may influence the severity of HFMD caused by EV71 infection. This observational study attempts to explore whether single-nucleotide polymorphisms (SNPs) in DC-SIGN are related to the severity of EV71-associated HFMD. Based on linkage disequilibrium and functional predictions, two DC-SIGN SNPs were selected and tested to explore their potential association with the severity of HFMD caused by EV71 infection. Two hundred sixteen Han Chinese children with HFMD caused by EV71 were enrolled to obtain clinical data, including the severity of HFMD, serum DC-SIGN levels, and DC-SIGN SNPs. We found a significant association between the rs7248637 polymorphism (A vs. G: OR = 0.644, 95% CI = 0.515-0.806) and the severity of HFMD caused by EV71 infection, as well as the rs4804800 polymorphism (A vs. G: OR = 1.539, 95% CI =1.229-1.928). These two DC-SIGN SNPs may have an effect on the severity of HFMD caused by EV71 infection.

Diagnostic value of loop-mediated isothermal amplification assay for hand, foot, and mouth disease.

BACKGROUND: Nowadays, hand, foot, and mouth disease (HFMD) has a significant negative impact on children's health, especially in the Asia-Pacific region. Loop-mediated isothermal amplification assay (LAMP) is a highly efficient and convenient novel tool. However, its diagnostic accuracy for HFMD is still not clear. Therefore, we conducted a meta-analysis in order to evaluate the potential of LAMP assay for the diagnosis of HFMD, in which the reference standard was polymerase chain reaction (PCR). METHODS: A protocol was predetermined (CRD42020212882) in PROSPERO. We retrieved seven databases including PubMed for relevant studies published before October 2020. Articles were included if they compared the diagnostic efficiency of LAMP with PCR for HFMD through detecting clinical samples which was more than 15. Statistical analysis was performed by STATA 15.1 software. Risk of bias and applicability were assessed using Quality Assessment of Diagnostic Accuracy Studies. No funding was used for the study. RESULTS: A total of 18 retrospective studies including 2495 samples from China were finally included. Reference standards of them included RT-PCR and non-RT-PCR. The merged sensitivity and specificity with 95% confidence interval (95% CI) were 1.00 (0.97-1.00) and 0.97 (0.88-0.99), respectively. The pooled PLR, NLR, and DOR with 95% CI were 11.17 (5.91-21.11), 0.05 (0.03-0.09), and 538.12 (183.17-1580.83), respectively. The AUC of SROC was 1.00 (95% CI: 0.99-1.00). CONCLUSION: In conclusion, our research revealed high sensitivity and specificity of LAMP in diagnosing HFMD. However, more high-quality research is required to prove this conclusion.

Association of gene polymorphisms of CD55 with susceptibility to and severity of hand, foot, and mouth disease caused by enterovirus 71 in the Han Chinese population.

Hand, foot, and mouth disease (HFMD) caused by enterovirus 71 (EV71) can lead to high morbidity and mortality, and genetic background plays an important role during the disease process. We investigated the association between the single-nucleotide polymorphism (SNP) rs2564978 of the CD55 gene and susceptibility to and severity of HFMD using the SNPs can multiple SNP typing methods. Soluble CD55 (sCD55) expression was significantly lower in the EV71 HFMD group than in the control group and lower in severe cases than in mild cases (P < .001). Moreover, CD55 rs2564978 (C vs T OR = 1.300, 95% CI, 1.120-1.509) was associated with the risk of EV71 infection, and genotype TC was related to the severity of the infection (TC vs TT OR = 4.523, 95% CI, 2.033-10.066). Our results suggest that sCD55 expression and the CD55 polymorphism rs2564978 may influence the susceptibility to and severity of EV71 infection.

Association of polymorphisms in the vitamin D receptor gene with susceptibility to and severity of hand, foot, and mouth disease caused by coxsackievirus A16.

Coxsackievirus A16 (CA16) remains the most common causative agent of hand, foot, and mouth disease (HFMD), and is related to high incidence and critical complications. Vitamin D receptor (VDR) activity might affect the outcome of CA16 infection. Our case-control research aims to evaluate the relationship between VDR polymorphisms in the gene encoding and susceptibility to and severity of HFMD due to CA16. Three single-nucleotide polymorphisms (SNPs) of VDR gene were selected according to functional prediction and linkage disequilibrium, and were examined utilizing the SNPscan method to identify possible associations with HFMD caused by CA16. A significant relationship was found in the HFMD cases of polymorphism rs11574129 (GA vs GG: odds ratio (OR) = 0.068, 95% confidence interval (CI) = 0.007-0.693, P = .023; GA + AA vs GG: OR = 0.322, 95%CI = 0.106-0.984, P = .047), and vitamin D levels in genotype AA were significantly higher than those in genotype GG (P < .05). These results suggest that VDR rs11574129 may influence genetic susceptibility to CA16-associated HFMD.

Vitamin D receptor gene methylation in patients with hand, foot, and mouth disease caused by enterovirus 71.

To evaluate the epigenetic regulation of the VDR gene in enterovirus 71 (EV71)-associated severe hand, foot, and mouth disease (HFMD), a total of 116 patients with EV71-HFMD, including 58 with mild EV71-HFMD and 58 with severe EV71-HFMD, as well as 60 healthy controls, were enrolled in this study. Quantitative real-time PCR was used to measure the relative levels of VDR mRNA expression, and the methylation status of the VDR promoter was assessed using a MethylTarget™ assay. The DNA methylation levels of the VDR promoter in children with EV71-associated severe HFMD were lower than those in the healthy controls and in children with mild HFMD (P < 0.05). Hypomethylation at CpG site 133 and hypermethylation at the CpG 42 sites and 68 downregulated VDR expression. Moreover, the methylation level of VDR could be used for differential diagnosis of mild and severe EV71-associated HFMD (AUC56, 0.73; AUC68, 0.699; AUC42, 0.694; AUC66, 0.693). VDR expression and promoter methylation were associated with the progression of EV71 infection. Determining the VDR promoter status might help clinicians initiate the appropriate strategy for treatment of EV71-associated HFMD.

Association of polymorphisms in the vitamin D receptor gene with severity of hand, foot, and mouth disease caused by enterovirus 71.

Severe hand, foot, and mouth disease (HFMD) is sometimes associated with critical complications that can cause substantial child mortality. Activity of the vitamin D receptor (VDR) may influence the outcomes of enterovirus 71 (EV71) infection. This case-control study aimed to assess the association of single-nucleotide polymorphisms (SNPs) in the gene encoding the VDR with the severity of EV71-associated HFMD. We selected four VDR SNPs based on linkage disequilibrium and functional prediction, and we tested them using the SNPscan multiple SNP typing method for potential association with severity of EV71-associated HFMD. We found a significant association in the case of rs11574129 (G vs A: odds ratio (OR), 0.3439; 95% confidence intervals (CI), 0.1778-0.6653) and rs739837 (T vs G: OR, 0.5580; 95%CI, 0.3352-0.9291). Our results suggest that these two SNPs may influence the severity of EV71-associated HFMD.

Overview of recent advances in liposomal nanoparticle-based cancer immunotherapy.

The clinical performance of conventional cancer therapy approaches (surgery, radiotherapy, and chemotherapy) has been challenged by tumor metastasis and recurrence that is mainly responsible for cancer-caused mortalities. The cancer immunotherapy is being emerged nowadays as a promising therapeutic modality in order to achieve a highly efficient therapeutic performance while circumventing tumor metastasis and relapse. Liposomal nanoparticles (NPs) may serve as an ideal platform for systemic delivery of the immune modulators. In this review, we summarize the cutting-edge progresses in liposomal NPs for cancer immunotherapy, with focus on dendritic cells, T cells, tumor cells, natural killer cells, and macrophages. The review highlights the major challenges and provides a perspective regarding the clinical translation of liposomal nanoparticle-based immunotherapy.

Association of gene polymorphisms of pattern-recognition receptor signaling pathway with the risk and severity of hand, foot, and mouth disease caused by enterovirus 71 in Chinese Han population.

Hand, foot, and mouth disease (HFMD) caused by enterovirus 71 (EV71) presents with a wide variety of clinical manifestations. Host immune response is a factor that influences disease susceptibility and severity. We investigated the potential association of gene polymorphisms in the pattern recognition receptor (PRR) pathway with the risk and severity of EV71 infection. A total of 180 EV71 HFMD cases (108 severe case; 72 mild cases) were enrolled. A group of 201 sex- and age-matched children was included as a control. All subjects were genotyped for the most common single-nucleotide polymorphisms (SNPs) in the PRR and the PRR signaling pathway using the SNPscan multiple SNP typing method. Binary logistic regression analysis revealed statistically significant differences in polymorphism of RIG-1 between patients and controls (rs3739674 G vs C: OR = 1.502, 95%CI: 1.120-2.014; rs9695310 G vs C: OR = 1.782, 95%CI: 1.312-2.419). Polymorphisms of RIG-1 rs3739674 (G vs C: OR = 2.047, 95%CI: 1.307-3.205) and TLR3 rs5743305 (A vs T: OR = 0.346, 95%CI: 0.212-0.566) were found to be associated with disease severity. The results indicated that RIG-1 (rs3739674 and rs9695310) polymorphisms are associated with an increased risk of EV71-induced HFMD in Chinese children, whereas RIG-1 rs3739674 and TLR3 rs5743305 polymorphisms are associated with disease severity. These findings support an important role of innate immune mechanism in EV71 infection.

IR-780-loaded polymeric micelles enhance the efficacy of photothermal therapy in treating breast cancer lymphatic metastasis in mice.

Cancer metastasis is responsible for over 90% of breast cancer-related deaths, and inhibiting lymph node metastasis is an option to treat metastatic disease. Herein, we report the use of IR-780-loaded polymeric micelles (IPMs) for effective photothermal therapy (PTT) of breast cancer lymphatic metastasis. The IPMs were nanometer-sized micelles with a mean diameter of 25.6 nm and had good stability in simulated physiological solutions. Under 808-nm laser irradiation, IPMs exhibited high heat-generating capability in both in vitro and in vivo experiments. After intravenous injection, IPMs specifically accumulated in the tumor and metastatic lymph nodes and penetrated into these tissues. Moreover, a single IPMs treatment plus laser irradiation significantly inhibited primary tumor growth and suppressed lymphatic metastasis by 88.2%. Therefore, IPMs are an encouraging platform for PTT applications in treatment of metastatic breast cancer.

Co-delivery of docetaxel and silibinin using pH-sensitive micelles improves therapy of metastatic breast cancer.

Breast cancer is the most vicious killer for women, and tumor metastasis is one of the leading causes of breast cancer therapy failure. In this study, a new pH-sensitive polymer (polyethylene glycol-block-poly[(1,4-butanediol)-diacrylate-ß-N,N-diisopropylethylenediamine], BDP) was synthesized. Based on BDP, docetaxel/silibinin co-delivery micelles (DSMs) was constructed. DSM had a well-defined spherical shape under the transmission electron microscope with average hydrodynamic diameter of 85.3±0.4 nm, and were stable in the bloodstream but could dissociate to release the chemotherapeutic agents in the low pH environment of the endo/lysosomes in the tumor cells. Compared with free drugs, DSM displayed greatly enhanced cellular uptake, higher cytotoxicity and a stronger anti-metastasis effect against mouse breast cancer cell line 4T1. In 4T1 tumor-bearing mice treated with DSM (twice a week for 3 weeks), the inhibition rate on tumor growth and metastasis reached 71.9% and 80.1%, respectively. These results reveal that DSM might be a promising drug delivery system for metastatic breast cancer therapy.

Treating breast cancer metastasis with cabazitaxel-loaded polymeric micelles.

Cancer metastasis is the primary cause of high mortality in breast cancer patients. In this study, we loaded an anti-cancer drug, cabazitaxel (CTX), into polymeric micelles (CTX-loaded polymeric micelles, PCMs), and explored their therapeutic efficacy in breast cancer metastasis. The characteristics of PCMs were investigated, and their anti-metastatic efficacy was assessed using in vitro and in vivo evaluations. PCMs had an average diameter of 50.13±11.96 nm with a CTX encapsulation efficiency of 97.02%±0.97%. PCMs could be effectively internalized into metastatic 4T1 breast cancer cells in vitro. CTX (10 ng/mL) or an equivalent concentration in PCMs did not significantly affected the viability of 4T1 cells, but dramatically decreased the cell migration activities. In an orthotopic metastatic breast cancer model, intravenously administered PCMs could be efficiently delivered to the tumor sites, resulting in a 71.6% inhibition of tumor growth and a 93.5% reduction of lung metastases. Taken together, our results verify the anti-metastatic efficacy of PCMs, thus providing an encouraging strategy for treating breast cancer metastasis.

N-terminal pro-brain natriuretic peptide levels associated with severe hand, foot and mouth disease.

BACKGROUND: Severe hand, foot, and mouth disease (HFMD) is sometimes associated with serious complications such as acute heart failure that can cause substantial child mortality. N-terminal pro-brain natriuretic peptide (NT-proBNP) is a sensitive and specific biomarker of congestive heart failure. The aim of this study was to use plasma NT-proBNP levels to establish the severity of childhood HFMD. METHODS: A retrospective study was performed in 128 Chinese patients with severe HFMD and 88 patients with mild HFMD treated between January 2014 and October 2015. Univariate and multiple logistic regression analyses were used to analyze the risk factors for severe HFMD. NT-proBNP levels were analyzed in 128 severe HFMD patients, and the predictive value of NT-proBNP was assessed by receiver operating characteristic analyses. RESULTS: Multivariate analysis controlling for several potential confounders showed that enterovirus 71 infection [odds ratio (OR) 19.944, 95 % confidence interval (CI) 6.492-61.271], peripheral WBC count (OR 3.428, 95 % CI 1.186-9.914), fasting glucose (OR 19.428, 95 % CI 2.236-168.784), procalcitonin (OR 9.084, 95 % CI 3.462-23.837, and NT-proBNP (>125 pg/mL) (OR 16.649, 95 % CI 4.731-58.585) were each associated with the severity of HFMD. The 45 dead severe patients had higher pre-procedural levels of NT-proBNP than the 83 cured severe patients (12776 ± 13115 versus 1435 ± 4201 pg/mL, P < 0.001). An NT-proBNP cutoff value of 982 pg/mL predicted mortality with 87 % sensitivity and 86 % specificity. CONCLUSION: Plasma NT-pro-BNP level appears to be a useful biological marker for predicting the severity and mortality of HFMD.

Biomaterials promote in vivo generation and immunotherapy of CAR-T cells.

Chimeric antigen receptor-T (CAR-T) cell therapy based on functional immune cell transfer is showing a booming situation. However, complex manufacturing processes, high costs, and disappointing results in the treatment of solid tumors have limited its use. Encouragingly, it has facilitated the development of new strategies that fuse immunology, cell biology, and biomaterials to overcome these obstacles. In recent years, CAR-T engineering assisted by properly designed biomaterials has improved therapeutic efficacy and reduced side effects, providing a sustainable strategy for improving cancer immunotherapy. At the same time, the low cost and diversity of biomaterials also offer the possibility of industrial production and commercialization. Here, we summarize the role of biomaterials as gene delivery vehicles in the generation of CAR-T cells and highlight the advantages of in-situ construction in vivo. Then, we focused on how biomaterials can be combined with CAR-T cells to better enable synergistic immunotherapy in the treatment of solid tumors. Finally, we describe biomaterials' potential challenges and prospects in CAR-T therapy. This review aims to provide a detailed overview of biomaterial-based CAR-T tumor immunotherapy to help investigators reference and customize biomaterials for CAR-T therapy to improve the efficacy of immunotherapy.

Telaprevir for chronic hepatitis C with genotype 1: a meta-analysis.

BACKGROUND/AIMS: The examination of HCV virological clearance through several randomized clinical trials of telaprevir in genotype 1 chronic hepatitis C. METHODOLOGY: We analyzed the effect of telaprevir on the end of treatment virological response and the sustained response, and investigated its harmful effect using meta-analysis of 5 randomized controlled trials. RESULTS: Overall analysis revealed a significant effect of telaprevir in both naive patients (RR, 1.32; 95% CI, 1.08-1.60) and previously failed treated patients (p<0.0001). Monotherapy and double therapy seemed to show no effect in naive patients. Triple therapy followed with PegIFN-2a plus ribavirin seemed to be effective in both naive patients and previously failed treated patients. Telaprevir was associated with a significantly higher incidence of serious adverse events (RR, 1.45; 95% CI, 1.00-2.10) and with discontinuation (RR, 2.23; 95% CI, 1.40-3.55) because of adverse events. In naive patients, relapsers and non-responders, the regimen of telaprevir/ PegIFN-2a/ribavirin for 12 weeks followed by PegIFN-2a/ribavirin for 12 weeks (T12PR24) was the optimal regimen regarding to efficiency and duration. CONCLUSIONS: Telaprevir combined with PegIFN-2a plus ribavirin may improve sustained response in genotype 1 chronic hepatitis C. Regimen T12PR24 may be the best regimen in this respect. New randomized controlled trials are required to confirm this meta-analysis.

DNA methylation and single-nucleotide polymorphisms in DDX58 are associated with hand, foot and mouth disease caused by enterovirus 71.

BACKGROUND: This research aimed to explore the association between the RIG-I-like receptor (RIG-I and MDA5 encoded by DDX58 and IFIH1, respectively) pathways and the risk or severity of hand, foot, and mouth disease caused by enterovirus 71 (EV71-HFMD). In this context, we explored the influence of gene methylation and polymorphism on EV71-HFMD. METHODOLOGY/PRINCIPAL FINDINGS: 60 healthy controls and 120 EV71-HFMD patients, including 60 mild EV71-HFMD and 60 severe EV71-HFMD patients, were enrolled. First, MiSeq was performed to explore the methylation of CpG islands in the DDX58 and IFIH1 promoter regions. Then, DDX58 and IFIH1 expression were detected in PBMCs using RT-qPCR. Finally, imLDR was used to detect DDX58 and IFIH1 single-nucleotide polymorphism (SNP) genotypes. Severe EV71-HFMD patients exhibited higher DDX58 promoter methylation levels than healthy controls and mild EV71-HFMD patients. DDX58 promoter methylation was significantly associated with severe HFMD, sex, vomiting, high fever, neutrophil abundance, and lymphocyte abundance. DDX58 expression levels were significantly lower in mild patients than in healthy controls and lower in severe patients than in mild patients. Binary logistic regression analysis revealed statistically significant differences in the genotype frequencies of DDX58 rs3739674 between the mild and severe groups. GeneMANIA revealed that 19 proteins displayed correlations with DDX58, including DHX58, HERC5, MAVS, RAI14, WRNIP1 and ISG15, and 19 proteins displayed correlations with IFIH1, including TKFC, IDE, MAVS, DHX58, NLRC5, TSPAN6, USP3 and DDX58. CONCLUSIONS/SIGNIFICANCE: DDX58 expression and promoter methylation were associated with EV71 infection progression, especially in severe EV71-HFMD patients. The effect of DDX58 in EV71-HFMD is worth further attention.

DNA methylation and SNP in IFITM3 are correlated with hand, foot and mouth disease caused by enterovirus 71.

OBJECTIVES: To explore the mechanisms of interferon-induced transmembrane protein 3 (IFITM3) in response to enterovirus-71-associated hand, foot and mouth disease (EV71-HFMD), in terms of DNA methylation, single-nucleotide polymorphism (SNP) genotype and gene expression. METHODS: In total, 120 patients with EV71-HFMD (60 with mild EV71-HFMD and 60 with severe EV71-HFMD) and 60 healthy controls were enrolled in this study. SNP genotype, IFITM3 promoter methylation and mRNA expression of peripheral blood mononuclear cells were examined using the improved multi-temperature ligase detection reaction, quantitative reverse transcriptase polymerase chain reaction and MiSeq, respectively. RESULTS: The distribution of methylation in patients with EV71-HFMD was significantly lower compared with healthy controls, and the severe EV71-HFMD group showed the lowest frequency of IFITM3 promoter methylation. The average level of IFITM3 promoter CpG methylation was negatively correlated with IFITM3 mRNA expression, and hypermethylation of several specific CpG units contributed to IFITM3 downregulation. IFITM3 expression and promoter methylation correlated with EV71 infection progression, especially in the severe EV71-HFMD group. Compared with mild cases, genotype GG and the G allele of rs12252 were over-represented in patients with severe EV71-HFMD. CONCLUSIONS: IFITM3 methylation status and SNP genotyping may help clinicians to choose the correct treatment strategy for patients with EV71-HFMD.

Add-on pegylated interferon augments hepatitis B surface antigen clearance vs continuous nucleos(t)ide analog monotherapy in Chinese patients with chronic hepatitis B and hepatitis B surface antigen ≤ 1500 IU/mL: An observational study.

BACKGROUND: Nucleos(t)ide analog (NA) has shown limited effectiveness against hepatitis B surface antigen (HBsAg) clearance in chronic hepatitis B (CHB) patients. AIM: To evaluate the efficacy and safety of add-on peginterferon α-2a (peg-IFN α-2a) to an ongoing NA regimen in CHB patients. METHODS: In this observational study, 195 CHB patients with HBsAg ≤ 1500 IU/mL, hepatitis B e antigen (HBeAg)-negative (including HBeAg-negative patients or HBeAg-positive patients who achieved HBeAg-negative after antiviral treatment with NA) and hepatitis B virus-deoxyribonucleic acid < 1.0 × 102 IU/mL after over 1 year of NA therapy were enrolled between November 2015 and December 2018 at the Second Affiliated Hospital of Xi'an Jiaotong University, China. Patients were given the choice between receiving either peg-IFN α-2a add-on therapy to an ongoing NA regimen (add-on group, n = 91) or continuous NA monotherapy (monotherapy group, n = 104) after being informed of the benefits and risks of the peg-IFN α-2a therapy. Total therapy duration of peg-IFN α-2a was 48 wk. All patients were followed-up to week 72 (24 wk after discontinuation of peg-IFN α-2a). The primary endpoint was the proportion of patients with HBsAg clearance at week 72. RESULTS: Demographic and baseline characteristics were comparable between the two groups. Intention-to-treatment analysis showed that the HBsAg clearance rate in the add-on group and monotherapy group was 37.4% (34/91) and 1.9% (2/104) at week 72, respectively. The HBsAg seroconversion rate in the add-on group was 29.7% (27/91) at week 72, and no patient in the monotherapy group achieved HBsAg seroconversion at week 72. The HBsAg clearance and seroconversion rates in the add-on group were significantly higher than in the monotherapy group at week 72 (P < 0.001). Younger patients, lower baseline HBsAg concentration, lower HBsAg concentrations at weeks 12 and 24, greater HBsAg decline from baseline to weeks 12 and 24 and the alanine aminotransferase ≥ 2 × upper limit of normal during the first 12 wk of therapy were strong predictors of HBsAg clearance in patients with peg-IFN α-2a add-on treatment. Regarding the safety of the treatment, 4.4% (4/91) of patients in the add-on group discontinued peg-IFN α-2a due to adverse events. No severe adverse events were noted. CONCLUSION: Peg-IFN α-2a as an add-on therapy augments HBsAg clearance in HBeAg-negative CHB patients with HBsAg ≤ 1500 IU/mL after over 1 year of NA therapy.

Doxorubicin conjugate of poly(ethylene glycol)-block-polyphosphoester for cancer therapy.

Polyphosphoesters with repeating phosphoester linkages in the backbone can be easily functionalized, are biodegradable and potentially biocompatible, and may be potential candidates as polymer carriers of drug conjugates. Here, the efficacy of a polyphosphoester drug conjugate as an anticancer agent in vivo is assessed for the first time. With controlled synthesis, doxorubicin conjugated to poly(ethylene glycol)-block-polyphosphoester (PPEH-DOX) via labile hydrazone bonds form spherical nanoparticles in aqueous solution with an average diameter of ≈60 nm. These nanoparticles are effectively internalized by MDA-MB-231 breast cancer cells and release the conjugated doxorubicin in response to the intracellular pH of endosomes and lysosomes, resulting in significant antiproliferative activity in cancer cells. Compared with free doxorubicin injection, PPEH-DOX injection exhibits much longer circulation behavior in the plasma of mice and leads to enhanced drug accumulation in tumor cells. In an MDA-MB-231 xenograft murine model, inhibition of tumor growth with systemic delivery of PPEH-DOX nanoparticles is more pronounced compared with free doxorubicin injection, suggesting the potential of polyphosphoesters as carriers of drug conjugates in cancer therapy.

[Efficacy of flowable composite resin as stress-absorbing liners in Class I cavity restorations].

OBJECTIVE: To evaluate the efficacy of flowable composite resin(FCR) as stress-absorbing liners in Class I cavity restorations in vitro. METHODS: Thirty Class I cavities of 4 mm in diameter and 2 mm in depth were prepared in polycarbonate (PC) plates and divided into three groups, ten each. After application of an adhesive, cavities in each group were restored using one of the following methods: A: restored with Charisma without any lining of FCR; B: lined with Revolution Formula 2 twice before restoration with Charisma; C: lined with Teric Flow twice before restoration with Charisma. All cavities were observed under a photoelastic microscope and photoelastic images were recorded at 3 min and 24 h after curing and the shrinkage stresses on the cavity wall were calculated. The polymerization shrinkage(v%) of the three composite resins was measured using bonded discs method and their elastic moduli were measured according to ISO standard. RESULTS: The shrinkage stresses at 3 min and 24 h of the three methods were as follows,A: (4.93 ± 0.28), (5.87 ± 0.40) MPa, B: (4.90 ± 0.30), (5.84 ± 0.33) MPa, and C: (4.76 ± 0.28),(5.83 ± 0.37) MPa.No significant difference was found in results among different groups. The polymerization shrinkage(v%) in group A,B, and C were (2.63 ± 0.04)%, (4.56 ± 0.06)%, and (3.98 ± 0.02)%. The elastic modulus in group A, B, and C were (9.59 ± 0.65), (4.25 ± 0.51), and (5.41 ± 0.79) GPa. CONCLUSIONS: Under present study condition, using a FCR as stress-absorbing liner under composite resin restoration does not significantly decrease the polymerization shrinkage stresses at the cavity wall.

[Gene delivery system based on low molecular weight polyethylenimine and its transfection activity in the skin tissue].

Low molecular weight polyethylenimine (LMW-PEI) was linked to an expressing plasmid contains a green fluorescence protein (GFP) reporter gene and effective gene transfer was observed in CM7221 cell line tested. We examined the relationship among the molecular weight, structure of PEI and their transfection activity and cytotoxicity on CM7221 cell line. We also examined the position and continuance time of the GFP reporter gene expressed in the skin tissue of mouse. Results showed that LMW-PEI/DNA complexes led to high levels of expression in the CM7221 cell line (about 55%). However, with the increasing of PEI molecular weight, the transfection activity of PEI was decreasing. There was an increasing cytotoxicity with the larger PEI molecules. Further research showed that LMW-PEI induced a significant and long-lasting (7 days) expression of the GFP reporter gene in the hair vesicle, sweat, gland, sebaceous gland in the mouse skin tissues. The LMW-PEI described here is a new, highly efficient and non-cytotoxic vector. It would be a useful non-viral vector for gene delivery technology, particular useful as simple skin-specific vehicles of therapeutic genes.