Glycopolymer Nanoparticles with On-Demand Glucose-Responsive Insulin Delivery and Low-Hypoglycemia Risks for Type 1 Diabetic Treatment.

Diabetic patients with type 1 or advanced type 2 stages need timely and precise insulin injection to regulate the daily blood glucose levels (BGLs). Otherwise, risks of serious or even deadly diabetes-associated complications occur. To achieve prolonged glucose regulation and low hypoglycemia risks, a novel on-demand glucose-responsive glycopolymer system was constructed for insulin delivery, which was self-assembled into nanoparticles by dynamic covalent bonds between two polymers: fluorophenylboronic acid-grafted polymer (poly-F) and polyol polymer (poly-G). Insulin was loaded during the assembly process. The nanoparticles showed excellent glucose responsiveness in vitro, with controlled insulin release at different glucose concentrations. In vivo treatment on type 1 diabetic mice showed prolonged BGL regulation and lower hypoglycemia risks. The mild preparation of the nanoparticles and outstanding glucose control shed light on the optional diabetic treatment for further clinical use.

NIR Activated Upper Critical Solution Temperature Polymeric Micelles for Trimodal Combinational Cancer Therapy.

The balance between drug efficiency and its side effects on normal tissues is still a challenging problem to be solved in current cancer therapies. Among different strategies, cancer therapeutic methods based on nanomedicine delivery systems have received extensive attention due to their unique advantages such as improved circulation and reduced toxicity of drugs in the body. Herein, we constructed dual-responsive polymeric micelles DOX&ALS@MFM based on an upper critical solution temperature (UCST) polymer to simultaneously combine chemotherapy, photothermal therapy (PTT), and photodynamic therapy (PDT). Amphiphilic block copolymer P(AAm-co-AN)-b-PEI-ss-PEG-FA with a critical point of 42 °C was able to self-assemble into polymeric micelles under physiological conditions, which further encapsulated anticancer drug doxorubicin (DOX) and photosensitizer ALS to obtain drug-loaded micelles DOX&ALS@MFM. Micelles aggregated at tumor sites due to folate targeting and an enhanced permeability retention (EPR) effect. After that, the high intracellular concentration of glutathione (GSH) and near-infrared (NIR) light prompted disassembly of the polymer to release DOX and ALS. ALS not only plays a role in PTT but also produces singlet oxygen, therefore killing tumor cells by PDT. Both in vitro and in vivo studies demonstrated the photothermal conversion and reactive oxygen species generation ability of DOX&ALS@MFM micelles, at the same time as the excellent inhibitory effect on tumor growth with NIR light irradiation. Thus, our research substantiated a new strategy for the biomedical application of UCST polymers in the cited triple modal tumor therapy.

Effects of periodontal clinical database software in resident training during COVID-19 pandemic: a prospective observational study.

BACKGROUND: Dental residents in Guangdong, China, had fewer medical practice opportunities because of the pandemic of COVID-19. This study aimed to evaluate whether a case-based learning (CBL) approach using a periodontal clinical database software (PCDS) could improve residents' achievement in the exam of the standardized residency training (SRT) program. METHODS: Forty-four dental residents volunteered and completed this trial. Within 12 weeks, all residents admitted periodontal patients 5 days a week and participated in a case-based learning course using PCDS once a week. Two online case-based examinations were used to evaluate their diagnostic and therapeutic performance before and after training. The total accuracy rate of examinations and the accuracy rate of subitems were analyzed using paired samples T-test. The Bonferroni correction is used for multiple testing adjustments, and p < 0.05 was considered statistical significance. RESULTS: After training, the total accuracy rate of SRT exams raised from 65 to 76%. There was a significant difference in the accuracy rate before and after training (Mean = 0.103, SD = 0.141, p < 0.001). The accuracy of radiographic examination (type of alveolar bone absorption and hard tissue lesion of tooth) and making treatment plan was significantly improved after training (p < 0.005). However, residents' performance in diagnosing periodontitis and predicting the prognosis of affected teeth was not improved. CONCLUSIONS: The PCDS and CBL method effectively improved the residents' achievement in SRT examination, especially in identifying the type of resorption of alveolar bone and the hard tissue lesion of a tooth by radiographic examination and making an appropriate treatment plan for a periodontitis patient. More effective teaching approaches are needed to improve residents' accuracy of diagnosis of periodontitis using the 2018 classification in China.

Modified gingivoplasty for hereditary gingival fibromatosis: two case reports.

BACKGROUND: Hereditary gingival fibromatosis (HGF) is characterized by sub-epithelial fibromatosis of keratinized gingiva resulting in a fibrotic enlargement of keratinized gingiva. The treatment choice is gingivectomy, which can be performed with an internal or external bevel incision conventionally. However, both techniques can hardly resume the natural status of gingiva, and have a certain recurrence rate, especially in the cases which have limited width of attached gingiva. CASE DESCRIPTION: Two cases of HGF with the chief complaint of difficulty in mastication, pronunciation, and poor esthetics were presented. After the initial periodontal therapy, a novel gingivoplasty modified with a crevicular incision was applied. A full thickness flap above the mucogingival junction and a split flap below the junction were raised. Then, fibrotic connective tissue was completely eliminated and keratinized gingival epithelium was preserved. The fibrotic alveolar bone was shaped by handpiece and bur. Finally, the flap was apically repositioned and sutured. Twelve months after surgery, the gingiva recovered with normal color, contour and consistency. CONCLUSIONS: Compared to traditional gingivectomy, modified gingivoplasty which focuses on eliminating pathological fibrotic connective tissue can completely resume the natural appearance of gingiva and demonstrate no tendency of recurrence.

Palmitic Acid Curcumin Ester Facilitates Protection of Neuroblastoma against Oligomeric Aß40 Insult.

BACKGROUND/AIMS: The generation of reactive oxygen species (ROS) caused by amyloid-ß (Aß) is considered to be one of mechanisms underlying the development of Alzheimer's disease. Curcumin can attenuate Aß-induced neurotoxicity through ROS scavenging, but the protective effect of intracellular curcumin on neurocyte membranes against extracellular Aß may be compromised. To address this issue, we synthesized a palmitic acid curcumin ester (P-curcumin) which can be cultivated on the cell membrane and investigated the neuroprotective effect of P-curcumin and its interaction with Aß. METHODS: P-curcumin was prepared through chemical synthesis. Its structure was determined via nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). An MTT assay was used to assess Aß cytotoxicity and the protective effect of P-curcumin on SH-SY5Y cells. The effect of P-curcumin on Aß-induced ROS production in vitro and in vivo were assessed based on changes in dichlorofluorescein (DCF) fluorescence. A spectrophotometric method was employed to detect lipid peroxidation. To mimic the interaction of P-curcumin on cell membranes with Aß, liposomes were prepared by thin film method. Finally, the interactions between free P-curcumin and P-curcumin cultivated on liposomes and Aß were determined via spectrophotometry. RESULTS: A novel derivative, palmitic acid curcumin ester was prepared and characterized. This curcumin, cultivated on the membranes of neurocytes, may prevent Aß-mediated ROS production and may inhibit the direct interaction between Aß and the cellular membrane. Furthermore, P-curcumin could scavenge Aß-mediated ROS as curcumin in vitro and in vivo, and had the potential to prevent lipid peroxidation. Morphological analyses showed that P-curcumin was better than curcumin at protecting cell shape. To examine P-curcumin's ability to attenuate direct interaction between Aß and cell membranes, the binding affinity of Aß to curcumin and P-curcumin was determined. The association constants for free P-curcumin and curcumin were 7.66 × 104 M-1 and 7.61 × 105 M-1, respectively. In the liposome-trapped state, the association constants were 3.71 × 105 M-1 for P-curcumin and 1.44× 106 M-1 for curcumin. With this data, the thermodynamic constants of P-curcumin association with soluble Aß (ΔH, ΔS, and ΔG) were also determined. CONCLUSION: Cultivated curcumin weakened the direct interaction between Aß and cell membranes and showed greater neuroprotective effects against Aß insult than free curcumin.

A straightforward ninhydrin-based method for collagenase activity and inhibitor screening of collagenase using spectrophotometry.

Currently protease assay kits, requiring substrate that is either radiolabeled or fluorescence labeled and specialized instruments, are all expensive. A simple, reliable assay of protease activity and its inhibitor screening for general laboratory is rare. Here we demonstrated a straightforward ninhydrin-based method for assay of collagenase activity and its inhibitor screening using spectrophotometry. In the method, without multistep sample treatments and substrate labeling, the hydrolytic products were directly traced by ninhydrin. The method is expected to be suitable for not only the assay of collagenase activity but also the others matrix metalloproteinases activities, and can be used for kinetic study.

Self-cleaning poly(dimethylsiloxane) film with functional micro/nano hierarchical structures.

This paper reports a novel single-step wafer-level fabrication of superhydrophobic micro/nano dual-scale (MNDS) poly(dimethylsiloxane) (PDMS) films. The MNDS PDMS films were replicated directly from an ultralow-surface-energy silicon substrate at high temperature without any surfactant coating, achieving high precision. An improved deep reactive ion etching (DRIE) process with enhanced passivation steps was proposed to easily realize the ultralow-surface-energy MNDS silicon substrate and also utilized as a post-treatment process to strengthen the hydrophobicity of the MNDS PDMS film. The chemical modification of this enhanced passivation step to the surface energy has been studied by density functional theory, which is also the first investigation of C4F8 plasma treatment at molecular level by using first-principle calculations. From the results of a systematic study on the effect of key process parameters (i.e., baking temperature and time) on PDMS replication, insight into the interaction of hierarchical multiscale structures of polymeric materials during the micro/nano integrated fabrication process is experimentally obtained for the first time. Finite element simulation has been employed to illustrate this new phenomenon. Additionally, hierarchical PDMS pyramid arrays and V-shaped grooves have been developed and are intended for applications as functional structures for a light-absorption coating layer and directional transport of liquid droplets, respectively. This stable, self-cleaning PDMS film with functional micro/nano hierarchical structures, which is fabricated through a wafer-level single-step fabrication process using a reusable silicon mold, shows attractive potential for future applications in micro/nanodevices, especially in micro/nanofluidics.

Engineering near-infrared laser-activated gold nanorod vesicles with upper critical solution temperature for photothermal therapy and chemotherapy.

Multimodal synergistic therapy based on nanomedicine drug delivery systems can achieve accurate cancer treatment. The anisotropy of gold nanorods (AuNRs) allows the adjustment of the longitudinal localized surface plasmon resonance absorption to the near-infrared band, which shows potential application in the field of photothermal therapy of cancer. Here, we report a new type of thermal-sensitive gold nanorod drug-loaded vesicles (UGRV-DOX) via the self-assembly of AuNRs modified with the amphiphilic polymer (PEG45-b-PS150) and upper critical solution temperature (UCST) polymer (P(AAm-co-AN)). The hollow structure of the vesicle can increase the drug loading capacity, and the polymers on its surface are intertwined to reduce drug leakage. As-prepared UGRV-DOX vesicles exhibits excellent photothermal conversion efficiency and can achieve light-controlled drug release. In vivo anti-tumor experiments showed that UGRV-DOX could ablate HepG2 transplanted tumors significantly under 808 nm laser irradiation, and the inhibition rate was as high as 99.3 %. These tumor-specific nanovesicles prefigure great potentials for high-precision cancer treatment.

Transcriptomic analysis reveals pathophysiological relationship between chronic obstructive pulmonary disease (COPD) and periodontitis.

BACKGROUND: The aim of this study was to detect potential crosstalk genes, pathways and immune cells between periodontitis and chronic obstructive pulmonary disease (COPD). METHODS: Chronic periodontitis (CP, GSE156993) and COPD (GSE42057, GSE94916) datasets were downloaded. Differential expressed genes (DEGs; p < 0.05) were assessed and screened for overlapping results, following functional pathway enrichment analyses (p < 0.05). The xCell method was used to assess immune cell infiltration relationship between CP and COPD. Features of the detected cross-talk genes were revealed using conventional Recursive Feature Elimination (RFE) algorithm in R project. Receiver-operating characteristic curves were applied to evaluate the predictive value of the genes. Furthermore, Pearson correlation analysis was performed on crosstalk markers and infiltrating immune cells in CP and COPD, respectively. RESULTS: A total of 904 DEGs of COPD and 763 DEGs of CP were acquired, showing 22 overlapping DEGs between the two diseases. Thereby 825 nodes and 923 edges were found in the related protein-protein-interaction network. Eight immune cell pairs were found to be highly correlated to both CP and COPD (|correlation coefficients |> 0.5 and p-value < 0.05). Most immune cells were differently expressed between COPD and CP. RFE identified three crosstalk genes, i.e. EPB41L4A-AS1, INSR and R3HDM1. In correlation analysis, INSR was positively correlated with Hepatocytes in CP (r = 0.6714, p = 0.01679) and COPD (r = 0.5209, p < 0.001). R3HDM was positively correlated with Th1 cells in CP (r = 0.6783, p = 0.0153) and COPD (r = 0.4120, p < 0.01). CONCLUSION: EPB41L4A-AS1, INSR and R3HDM1 are potential crosstalk genes between COPD and periodontitis. R3HDM was positively correlated with Th1 cells in both diseases, while INSR was positively correlated with Hepatocytes in periodontitis and COPD, supporting a potential pathophysiological relationship between periodontitis and COPD.

A decision-tree model for predicting extubation outcome in elderly patients after a successful spontaneous breathing trial.

BACKGROUND: The commonly used single tests, based on a 1-time measurement of a physiologic variable, are often poorly predictive of tracheal extubation outcome because they examine only a single aspect of physiological function that affects the extubation outcome. We hypothesized that the construction of a decision-tree model, which includes multiple variables and considers the changes of these variables, may more accurately predict successful extubation. METHODS: This was a prospective observational study. From 2007 to 2008, 113 elderly patients in the medical intensive care unit on ventilation for >48 hours were enrolled. All patients underwent a 60-minute spontaneous breathing trial (SBT) [positive end-expiratory pressure of 5 cm H(2)O; automatic tube compensation, 100%]. Patients tolerating the trial were extubated immediately. The mouth occlusion pressure (P(0.1)), rapid shallow breathing index (RSBI,) and their combination (P(0.1) × RSBI) were recorded at the first, 30th, and 60th minute of the SBT. The changes in RSBI, which were determined at the 30th and 60th minute of the SBT (ΔRSBI30, ΔRSBI60), were assessed as the ratio (of RSBI30 or RSBI60) to RSBI at the first minute of the SBT. RESULTS: Twenty-two patients (19.5%) failed the SBT and were not included in the analysis, and 91 tolerated the trial and were extubated. At 48 hours, 73 (80.2%) remained extubated (successful extubation), and 18 (19.8%) required reintubation (extubation failure). Although theΔRSBI(30) was significantly higher in the extubation failure patients (118% ± 34%) than that in the successful extubation patients (93% ± 35%, P = 0.01), the receiver operating characteristic (ROC) analysis demonstrated that this index, with the threshold of <98%, presented poor performance in predicting successful extubation with area under the ROC curve (AUC) of only 0.76. The classification and regression-tree analysis selected 3 variables (P(0.1) × RSBI(30), RSBI(1), ΔRSBI(30)) and began with P(0.1) × RSBI(30). For patients with P(0.1) × RSBI-(30) >474 cmH(2)O*breaths/min/L, ΔRSBI(30) >98% defined a group including all failure patients but no success patients, whereas ΔRSBI(30) ≤98% included all success patients with no failure patients. For patients with P(0.1) × RSBI(30) ≤474 cm H(2)O*breaths/min/L, the combination of both a P(0.1) × RSBI(30) >328 cm H(2)O*breaths/min/L and RSBI(1) >112 breaths/min/L also defined a group including all success patients but no failure patients. Indeed, the diagnostic accuracy (DA) of the tree model, which was 89.1% with only the P(0.1) × RSBI(30) included, increased to 94.5% when both the P(0.1) × RSBI(30) and ▵RSBI(30) were included. The final tree model with the inclusion of all 3 discriminators could capture the successful extubation with diagnostic accuracy of 96.7%, AUC of 0.94 (95% confidence interval [CI], 0.87 to 0.98). CONCLUSION: If the current tree model is confirmed by a prospective study with a larger sample size, it would be useful in guiding physicians making extubation decisions in elderly medical intensive care unit patients.

The interplay of lipopolysaccharide-binding protein and cytokines in periodontal health and disease.

AIM: Periodontal pathogenesis is characterized by Gram-negative bacteria activation of series of pro- and anti-inflammatory cytokines from host cells through the pathway of lipopolysaccharide (LPS), LPS-binding protein (LBP) and CD14. The present study investigated the expression profiles of interleukin (IL)-1beta and IL-10 in periodontal health and disease, and examined the effects of Escherichia coli LPS and LBP interaction on the expression of IL-1beta and IL-10 by human gingival fibroblasts (HGF). MATERIAL AND METHODS: Gingival biopsies were collected from 44 subjects with chronic periodontitis and 15 periodontally healthy subjects. The expression of IL-1beta and IL-10 was detected by immunohistochemistry. The mRNA expression of IL-1beta and IL-10 in HGF was detected by RT-PCR with or without recombinant human LBP (rhLBP), while the peptides were analysed by an enzyme-linked immunosorbent assay. RESULTS: IL-1beta was detected in both oral sulcular epithelia of healthy controls and periodontal pocket epithelia of patients. IL-10 was mainly expressed in the intercellular spaces of connective tissues. IL-1beta displayed a reverse pattern of expression levels with reference to IL-10, and a negative correlation existed between LBP and the ratio of IL-1beta/IL-10. rhLBP suppressed E. coli LPS-induced IL-1beta expression by HGF. CONCLUSION: An appropriate interplay of LBP and cytokines may have a beneficial effect on innate host defence, thereby contributing to periodontal homeostasis.

Advanced glycation end products inhibit the expression of collagens type I and III by human gingival fibroblasts.

BACKGROUND: It is evident that diabetes and periodontal disease are closely interrelated. Accumulation of advanced glycation end products (AGEs), coupled with exaggerated host responses to bacterial infection, may account for the increased periodontal destruction observed in patients with uncontrolled diabetes. The present study investigated the effects of AGEs on the viability of human gingival fibroblasts (HGFs) and the expression of types I and III collagen in HGFs. METHODS: The cell viability of HGFs was examined by methylthiazolet-etrazolium assay, whereas the expression of types I and III collagen message and protein was detected by real-time quantitative reverse transcription-polymerase chain reaction and sandwich enzyme-linked immunosorbent assay, respectively. RESULTS: AGEs significantly suppressed the cell viability of HGFs from 24 to 72 hours (P <0.01). A high concentration of glucose (25 mmol/l) in the culture media exaggerated the inhibition of the survival rate of HGFs (P <0.01). The expression of collagen types I and III messages and proteins was significantly downregulated at 72 hours by AGEs in a concentration-dependent manner (P <0.05). Moreover, the synthesis of intracellular types I and III collagen protein was markedly inhibited by AGEs (P <0.05). CONCLUSIONS: AGEs may suppress the cell viability of HGFs and downregulate the expression of types I and III collagen by the cells. Further investigations are warranted to clarify the molecular mechanisms of AGEs in the regulation of cell function and collagen metabolism in patients with diabetes and periodontitis.

The role of estrogen in osteogenetic cytokine expression in human periodontal ligament cells.

The purpose was to identify the effects of estrogen on the expression of alkaline phosphatase (ALP) and osteoprotegerin (OPG) in human periodontal ligament cells (hPDLCs). Cells were obtained from healthy periodontal tissue explants of teeth that had been extracted for orthodontic reasons. ALP activity was determined after 17b-estradiol (17b-E2) treatment at 0, 0.1, 1, 10, and 100 nmol/L by using assay reagents. OPG expression in hPDLCs was studied by enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction. It was shown that the ALP activity and the OPG protein production were increased in a time-dependent manner (P < .05). Whereas a physiologic concentration of 17b-E2 enhanced the secretion of OPG (P < .05) and the expression of OPG mRNA, a high dose (100 nmol/L) of 17b-E2 had no such effect on hPDLCs. It appears that estrogen may exert its antiresorptive effects and maintain periodontal health through stimulating ALP and OPG expression in hPDLCs. (Int J Periodontics Restorative Dent 2009;29:507-513.).

NFIC promotes the vitality and osteogenic differentiation of rat dental follicle cells.

Nuclear factor I-C (NFIC) plays critical roles in the regulation of tooth development by influencing the biological behaviors of stem cells in the dental germ. This study aimed to investigate the effect of NFIC on the vitality and osteogenic/cementogenic differentiation of rat dental follicle cells (DFCs). DFCs were isolated from dental follicles in the first molars of neonatal rats. DFCs expressed mesenchymal stromal cell markers CD29, CD44 and CD90 and had capabilities for self-renewal and multipotent differentiation. Overexpression of NFIC promoted the proliferation of DFCs without markedly influencing the apoptosis of DFCs. Moreover, NFIC increased alkaline phosphatase (ALP) activity in DFCs and upregulated the mRNA levels of osteogenic-related markers, namely, collagen type I (Col I), Runt-related transcription factor 2 (Runx2) and ALP, as well as ß-catenin. In contrast, silencing NFIC by siRNA increased the apoptosis of DFCs and downregulated the expression of osteogenic-related markers. In conclusion, these results suggested that upregulation of NFIC may promote the proliferation and osteogenic/cementogenic differentiation of DFCs.

[Influence of Six Digestion Methods on the Determination of Polystyrene Microplastics in Organisms Using the Fluorescence Intensity].

Microplastic pollution has become a global environmental problem and is a cause of great concern. To evaluate the biological effects of microplastics, microplastics in organisms need to be accurately quantified. The quantification of microplastics in organisms using the fluorescence intensity is common; the digestion of biological samples is an important pretreatment method. However, the microplastics may be destroyed by digestion, which affects the fluorescence intensity of the microplastics and results in large deviations between measured and true values. In this study, six commonly used digestive agents were studied:KOH, NaOH, H2O2, HNO3, HNO3:HCl, and HNO3:HClO4. The effect of different digestion methods on the fluorescence intensity and surface morphology of microplastics was studied and the most suitable protocol was selected. The results show that, among the six different digestion methods, KOH digestion (100 g·L-1, 60℃) has the least influence on the fluorescence intensity of the microplastics and does not affect their surface morphology. The other five digestion methods lead to different degrees of reduction of the fluorescence intensity of microplastics and damage the microplastics' surface (aggregation, bubbles, scratches, and depressions). In addition, the KOH digestion method was used to extract microplastics from biological samples. The recovery rate was ≥ 96.3%±0.5%, indicating that the KOH digestion method is suitable for fluorescent microplastics in biological samples.

Recent changes in the curriculum of Chinese dental schools.

Chinese dental education is organized and controlled by the government at different levels, and the curriculum is based on the stomatology model. The unique feature of this system has been a heavy emphasis on the medical sciences and the integration of medicine with dentistry. However, the problems with this curriculum have been greater than its advantages since a dental student trained under this educational model was unlikely to be well prepared for patient care in a clinical setting and could struggle to apply modern techniques during his or her professional career. From 1995 to 2000, six well-known Chinese dental schools participated in a curriculum innovation project supported by the central government. This article describes the educational model developed during the project and presents several new educational concepts that have been put into practice in dental schools in China. Nevertheless, the new model is not without problems. If there are no additional innovations related to didactic teaching methods, clinical education, and interpersonal skills, the outcome of recent changes in the curriculum of Chinese dental schools will be unpredictable, and our dental education will not continue to advance.

Perspectives on dental education in mainland China.

The Chinese dental education system has undergone major changes over the past three decades. Although a number of approaches have been adopted for the modification of the dental curriculum, the greatest challenge remains as to how to develop enough qualified dentists to meet the dental care needs of China's 1.3 billon population. In many areas the limited funds have been mainly used for the enhancement of academic status while the clinical training programmes for the improvement of practical skills of the clinicians has been greatly neglected. In addition, the discrepancies in the distribution of dental resources have been increasingly alarming and have the tendency toward becoming even more serious in the future. The aim of this review is to describe dental education in China in the hope that more favourable changes could take place and the system itself could be further optimised.

Inactivation of glutamate racemase (MurI) eliminates virulence in Streptococcus mutans.

Inhibition of enzymes required for bacterial cell wall synthesis is often lethal or leads to virulence defects. Glutamate racemase (MurI), an essential enzyme in peptidoglycan biosynthesis, has been an attractive target for therapeutic interventions. Streptococcus mutans, one of the many etiological factors of dental caries, possesses a series of virulence factors associated with cariogenicity. However, little is known regarding the mechanism by which MurI influences pathogenesis of S. mutans. In this work, a stable mutant of S. mutans deficient in glutamate racemase (S. mutans FW1718) was constructed to investigate the impact of murI inactivation on cariogenic virulence in S. mutans UA159. Microscopy revealed that the murI mutant exhibited an enlarged cell size, longer cell chains, diminished cell⬜cell aggregation, and altered cell surface ultrastructure compared with the wild-type. Characterization of this mutant revealed that murI deficiency weakened acidogenicity, aciduricity, and biofilm formation ability of S. mutans (P<0.05). Real-time quantitative polymerase chain reaction (qRT-PCR) analysis demonstrated that the deletion of murI reduced the expression of the acidogenesis-related gene ldh by 44-fold (P<0.0001). The expression levels of the gene coding for surface protein antigen P (spaP) and the acid-tolerance related gene (atpD) were down-regulated by 99% (P<0.0001). Expression of comE, comD, gtfB and gtfC, genes related to biofilm formation, were down-regulated 8-, 43-, 85- and 298-fold in the murI mutant compared with the wild-type (P<0.0001), respectively. Taken together, the current study provides the first evidence that MurI deficiency adversely affects S. mutans virulence properties, making MurI a potential target for controlling dental caries.

Attenuation of Porphyromonas gingivalis oral infection by α-amylase and pentamidine.

The Porphyromonas gingivalis bacterium is one of the most influential pathogens in oral infections. In the current study, the antimicrobial activity of α-amylase and pentamidine against Porphyromonas gingivalis was evaluated. Their in vitro inhibitory activity was investigated with the agar overlay technique, and the minimal inhibitory and bactericidal concentrations were determined. Using the bactericidal concentration, the antimicrobial actions of the inhibitors were investigated. In the present study, multiple techniques were utilized, including scanning electron microscopy (SEM), general structural analysis and differential gene expression analysis. The results obtained from SEM and bactericidal analysis indicated a notable observation; the pentamidine and α-amylase treatment destroyed the structure of the bacterial cell membranes, which led to cell death. These results were used to further explore these inhibitors and the mechanisms by which they act. Downregulated expression levels were observed for a number of genes coding for hemagglutinins and gingipains, and various genes involved in hemin uptake, chromosome replication and energy production. However, the expression levels of genes associated with iron storage and oxidative stress were upregulated by α-amylase and pentamidine. A greater effect was noted in response to pentamidine treatment. The results of the present study demonstrate promising therapeutic potential for α-amylases and pentamidine. These molecules have the potential to be used to develop novel drugs and broaden the availability of pharmacological tools for the attenuation of oral infections caused by Porphyromonas gingivalis.

Left ventricular dysfunction in children with fulminant enterovirus 71 infection: an evaluation of the clinical course.

We describe 2 children with typical hand, foot, and mouth disease due to enterovirus 71 infection, 1 of whom died. Both cases were complicated by acute fulminant shock syndrome; the patients had remarkable acute left ventricular dysfunction. The clinical experience indicates that the rapid death associated with fulminant enterovirus rhombencephalitis is the result of rapid cardiogenic shock rather than neurogenic pulmonary edema.