Guidelines derived from biomineralized tissues for design and construction of high-performance biomimetic materials: from weak to strong.

Living organisms in nature have undergone continuous evolution over billions of years, resulting in the formation of high-performance fracture-resistant biomineralized tissues such as bones and teeth to fulfill mechanical and biological functions, despite the fact that most inorganic biominerals that constitute biomineralized tissues are weak and brittle. During the long-period evolution process, nature has evolved a number of highly effective and smart strategies to design chemical compositions and structures of biomineralized tissues to enable superior properties and to adapt to surrounding environments. Most biomineralized tissues have hierarchically ordered structures consisting of very small building blocks on the nanometer scale (nanoparticles, nanofibers or nanoflakes) to reduce the inherent weaknesses and brittleness of corresponding inorganic biominerals, to prevent crack initiation and propagation, and to allow high defect tolerance. The bioinspired principles derived from biomineralized tissues are indispensable for designing and constructing high-performance biomimetic materials. In recent years, a large number of high-performance biomimetic materials have been prepared based on these bioinspired principles with a large volume of literature covering this topic. Therefore, a timely and comprehensive review on this hot topic is highly important and contributes to the future development of this rapidly evolving research field. This review article aims to be comprehensive, authoritative, and critical with wide general interest to the science community, summarizing recent advances in revealing the formation processes, composition, and structures of biomineralized tissues, providing in-depth insights into guidelines derived from biomineralized tissues for the design and construction of high-performance biomimetic materials, and discussing recent progress, current research trends, key problems, future main research directions and challenges, and future perspectives in this exciting and rapidly evolving research field.

Cell adhesion molecule BVES functions as a suppressor of tumor cells extrusion in hepatocellular carcinoma metastasis.

BACKGROUND: Tumor cells detachment from primary lesions is an early event for hepatocellular carcinoma (HCC) metastasis, in which cell adhesion molecules play an important role. The role of mechanical crowding has attracted increasing attention. Previous studies have found that overcrowding can induce live cells extrusion to maintain epithelial cell homeostasis, and normally, live extruded cells eventually die through a process termed anoikis, suggesting the potential of tumor cells resistant to anoikis might initiate metastasis from primary tumors by cell extrusion. We have demonstrated transmembrane adhesion molecule blood vessel epicardial substance (BVES) suppression as an early event in HCC metastasis. However, whether its suppression is involved in HCC cell extrusion, especially in HCC metastasis, remains unknown. This study aims to investigate the role of BVES in tumor cells extrusion in HCC metastasis, as well as the underlying mechanisms. METHODS: Cells extrusion was observed by silicone chamber, petri dish inversion, and three-dimensional cell culture model. Polymerase chain reaction, western blotting, immunohistochemistry, immunofluorescence, co-immunoprecipitation, and RhoA activity assays were used to explore the underlying mechanisms of cell extrusion regulated by BVES. An orthotopic xenograft model was established to investigate the effects of BVES and cell extrusion in HCC metastasis in vivo. RESULTS: Tumor cell extrusion was observed in HCC cells and tissues. BVES expression was decreased both in HCC and extruded tumor cells. BVES overexpression led to the decrease in HCC cells extrusion in vitro and in vivo. Moreover, our data showed that BVES co-localized with ZO-1 and GEFT, regulating ZO-1 expression and localization, and GEFT distribution, thus modulating RhoA activity. CONCLUSION: The present study revealed that BVES downregulation in HCC enhanced tumor cells extrusion, thus promoting HCC metastasis, which contributed to a more comprehensive understanding of tumor metastasis, and provided clues for developing novel HCC therapy strategies. Video abstract.

[Three-dimensional imaging for quantitative evaluation of facial profile of edentulous patients before and after complete dentures restoration].

OBJECTIVE: To collect and analyze the Three-dimensional (3D) facial profile variation of edentulous patients restored by complete denture. METHODS: The 3D facial images of 20 Atwood Class II edentulous patients were taken by DSC-2 3D facial imaging system before and after restoration of complete denture. Then, the two 3D facial images of each patient before and after restoration were registered in the same coordinate system by partial structure overlap. The differences between these two 3D facial images were statistically analyzed. RESULTS: The major facial profile variation of Atwood Class II edentulous patients restored by complete denture focused in the area around the upper lip and the corner of the mouth. The change of lower lip and chin area was not obvious. The shift in the sagittal direction was significantly more evident than that in the vertical direction, while the shift in the horizontal direction was the least one. CONCLUSION: The pattern of facial profile variation of edentulous patients restored by complete denture based on 3D imaging may provide reliable data support for prediction and communication in clinical practice.

Nutrition impact symptoms: Noteworthy prognostic indicators for lung cancer.

BACKGROUND: Nutrition impact symptoms (NIS) in head and neck cancer are well-studied and are found to be heavy contributors of poor outcome. However, the prevalence and role of NIS in other cancer are less addressed. In this study, we investigated the incidence and prognostic role of NIS in patients with lung cancer. METHODS: NIS, evaluated by patient-generated subjective global assessment (PG-SGA) in a multicenter real-world prospective study, included loss of appetite, nausea, vomiting, mouth ulcer, constipation, diarrhea, dry mouth, taste change, altered smell, dysphagia, early satiety, and pain. The endpoints were the patients' overall survival (OS) and quality of life (QoL). The COX analysis was used to investigate the relationship between NIS and OS. Interaction analysis and mediation analysis were performed to determine the modifiers and mediator. RESULTS: 3634 patients with lung cancer were enrolled in this study, of which 1533 patients had NIS. During the average follow-up of 22.65 months, 1875 deaths occurred. The OS of patients with lung cancer with NIS was lower than that of patients without NIS. NIS (HR, 1.181, 95% CI, 1.073-1.748), loss of appetite (HR, 1.266, 95% CI, 1.137-1.409), vomiting (HR, 1.282, 95% CI, 1.053-1.561), and dysphagia (HR, 1.401, 95% CI, 1.079-1.819) were independent prognostic factors in patients with lung cancer. There were interactions between chemotherapy and primary tumor on NIS . In the relationship between different types of NIS (NIS, loss of appetite, vomiting, dysphagia) and prognosis, the mediating effects of inflammation accounted for 15.76%, 16.49%, 26.32%, and 18.13%, respectively. Meanwhile, these three NIS were closely associated with the occurrence of severe malnutrition and cancer cachexia. CONCLUSIONS: 42% patients with lung cancer experienced different types of NIS. NIS were independent indicators of malnutrition, cancer cachexia and shorter OS, and closely related to QoL. NIS management is of clinical significance.

Caffeic acid-grafted-chitosan/polylactic acid film packaging enhances the postharvest quality of Agaricus bisporus by regulating membrane lipid metabolism.

In this study, the film assembled by caffeic acid-grafted-chitosan/polylactic acid (CA-g-CS/PLA) was used for packaging postharvest Agaricus bisporus, and its effects on postharvest quality of Agaricus bisporus by regulating membrane lipid metabolism were investigated. The results showed that compared to traditional polyethylene packaging, the cell morphology of Agaricus bisporus packaged by CA-g-CS/PLA demonstrated a more complete structure due to its lower permeability, higher fluidity and stronger ability to maintain free water. Meanwhile, CA-g-CS/PLA packaging could effectively delay the decrease rate of unsaturation value and phospholipids of Agaricus bisporus during storage. In addition, the activities and expression levels of lipoxygenase (LOX), phospholipase C (PLC) and phospholipase D (PLD) in Agaricus bisporus packaged with CA-g-CS/PLA were inhibited, while those of glycerol-3-phosphate acyltransferase (GPAT) and sphingomyelin synthase (SMS) were promoted. Therefore, CA-g-CS/PLA packaging could enhance the postharvest quality of Agaricus bisporus by regulating membrane lipid metabolism, which has great application potential in the field of new intelligent packaging.

Development and evaluation of an inactivated coxsackievirus A16 vaccine in gerbils.

Coxsackievirus A16 (CVA16) is one of the major pathogens responsible for human hand, foot, and mouth disease (HFMD), which has threatened the health of young children, particularly in Asia-Pacific nations. Vaccination is an effective strategy for protecting children from CVA16 infection. However, there is currently no licensed CVA16 vaccine for use in humans. In this study, we isolated a high-growth CVA16 virus strain in MRC-5 cells and developed an MRC-5-adapted vaccine candidate strain termed CVA16-393 via two rounds of plaque purification. The CVA16-393 strain was grouped into the B1b subgenotype and grew to a titre of over 107 TCID50/ml in MRC-5 cells. The VP1 gene region of this strain, which contains the major neutralizing epitopes, displayed high stability during serial passages. The inactivated whole-virus vaccine produced by the CVA16-393 strain induced an effective neutralizing antibody response in Meriones unguiculatus (gerbils) after two doses of intraperitoneal inoculation. One week after the booster immunization, the geometric mean titres of the neutralizing antibodies for the 10246, 40812TXT, 11203SD, TJ-224 and CA16-194 strains from different regions of China were 137.8, 97.8, 113.4, 64.1 and 122.3, respectively. A CVA16 vaccine dose above 25 U was also able to provide 100% cross-protection against lethal challenges with these five clinical strains in gerbils. Immunization at a one-week interval could maintain a high level of neutralizing antibody titres for at least 8 weeks. Thus, the vaccine produced by this CVA16-393 strain might be promising.

Assessment of the embolization effect of temperature-sensitive p(N-isopropylacrylamide-co-butyl methylacrylate) nanogels in the rabbit renal artery by CT perfusion and confirmed by macroscopic examination.

Transcatheter embolization is an important treatment method in clinical therapy, and vascular embolization material plays a key role in embolization. The temperature-sensitive p(N-isopropylacrylamide-co-butyl methylacrylate) (PIB) nanogel is a novel embolic agent. To evaluate the feasibility of the nanogel as a blood vessel embolization agent, we aimed to assess the effect of embolization with PIB nanogels in the rabbit renal artery by non-invasive computed tomography (CT) perfusion, macroscopic and histological examination. Ten healthy adult Japanese rabbits were used to implement RAE of PIB nanogels in their right kidneys. CT perfusion scans were performed pre- and post-treatment at various time-points (1, 4, 8, and 12 weeks). Two rabbits were euthanized and histologically examined at each time-point, and the remaining rabbits were euthanized at 12 weeks after embolization. The RAE efficacy of the nanogels was further confirmed by macroscopic and histological examination. The renal volume and renal blood flow (BF) of the right kidney were significantly decreased post-treatment compared with those pre-treatment (volume: pre, 9278 ± 1736 mm3; post 1 week, 5155 ± 979 mm3, P < 0.0001; post 4 weeks, 3952 ± 846 mm3, P < 0.0001; post 8 weeks, 3226 ± 556 mm3, P < 0.0001; post 12 weeks, 2064 ± 507 mm3, P < 0.0001. BF: pre, 530.81 ± 51.50 ml/min/100 ml; post 1 week, 0 ml/min/100 ml, P < 0.0001; post 4 weeks, 0 ml/min/100 ml, P < 0.0001; post 8 weeks, 0 ml/min/100 ml, P < 0.0001; post 12 weeks, 0 ml/min/100 ml, P < 0.0001). No revascularization or collateral circulation was observed on histological examination during this period, and PIB nanogels were dispersed in all levels of the renal arteries. Twelve weeks after embolization, CT perfusion showed no BF in the right renal artery and renal tissue, a finding that was consistent with histological examination showing complete embolization of the right renal artery with a lack of formation of collateral vessels. The effect of embolization on PIB was adequate, with good dispersion and permanency, and could be evaluated by non-invasive and quantitative CT perfusion.

Highly porous and elastic aerogel based on ultralong hydroxyapatite nanowires for high-performance bone regeneration and neovascularization.

Hydroxyapatite (HAP) is promising for the clinical treatment of bone defects because of its excellent biocompatibility and osteo-conductivity. However, highly porous HAP scaffolds usually exhibit high brittleness and poor mechanical properties, thus organic constituents are usually added to form composite materials. In this work, a highly porous and elastic aerogel made from ultralong HAP nanowires with ultrahigh porosity (∼98.5%), excellent elasticity and suitable porous structure is prepared as the high-performance scaffold for bone defect repair. The highly porous structure of the as-prepared aerogel is beneficial to bone ingrowth and matter/fluid transfer, and the high elasticity can ensure the structural integrity of the scaffold during bone regeneration. Therefore, the HAP nanowire aerogel scaffold can promote the adhesion, proliferation and migration of rat bone marrow derived mesenchymal stem cells (rBMSCs), and elevate the protein expression of osteogenesis and angiogenesis related genes. The in vivo experimental results demonstrate that the HAP nanowire aerogel scaffold is favorable for the ingrowth of new bone and blood vessels, and thus can greatly accelerate bone regeneration and neovascularization. The as-prepared HAP nanowire aerogel scaffold shows promising potential for biomedical applications such as bone defect repair.

Platysma skin flap: Laryngeal repair material to produce phonatory flap vibrational wave.

The platysma skin flap was used for laryngeal reconstruction after vertical partial laryngectomy to improve the postoperative voice quality of patients with T2 and T3 glottic laryngeal carcinoma. Sixty-nine patients with unilateral T2 and T3 glottic laryngeal carcinoma were included. Forty-six patients received vertical partial laryngectomy, and a platysma skin flap was used for laryngeal reconstruction. The other 23 patients underwent transoral laser microsurgery. Subjective and objective examinations were performed to evaluate laryngeal morphology after the surgery. Acceptable voice quality was achieved for 46 patients who underwent vertical partial laryngectomy. Flap vibrational waves occurred in 19 cases (41.3%). The platysma skin flap is an ideal tissue for the reconstruction of articulation structure in open surgery of T2 and T3 unilateral glottic laryngeal carcinoma.

Comparative analysis on the sorption kinetics and isotherms of fipronil on nondegradable and biodegradable microplastics.

Biodegradable plastics have been introduced and widely used as a promising alternative to traditional nondegradable plastics. However, the differences in sorption behavior of pesticides on nondegradable and biodegradable microplastics has been insufficiently studied. Here, four types of nondegradable [polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polypropylene (PP)] and two types of biodegradable [polylactic acid (PLA), polybutylene succinate (PBS)] microplastics were selected to investigate the sorption mechanism of fipronil based on their sorption kinetics and isotherms. The results indicated that the sorption rates of PLA and PBS were much higher than those of PE, PP, PVC and PS and that the sorption capacities of fipronil on microplastics followed the order of PBS > PLA > PP > PE > PS > PVC. The sorption kinetics followed a pseudo-second-order kinetics model (R2 = 0.953-0.998) for all tested microplastics. External mass transport and intraparticle diffusion were the main rate controlling steps of the sorption of fipronil on microplastics. Furthermore, isotherm results indicated that a Langmuir model provided the best fit for fipronil sorption on PE, PS, PVC and PP (R2 = 0.997-0.999), while a Freundlich model was the most appropriate model for PLA and PBS (R2 = 0.998-0.999). The presence of surface O-containing functional groups and the spatial arrangement of rubbery domains are likely to affect the sorption process. The results from this work suggest that microplastics, especially biodegradable ones, may play an important role in the fate and transport of pesticides, and their effects on soil organisms (e.g., earthworms) require further investigation.

Survey of nil per os duration of patients admitted to the emergency department due to vomiting.

During the acute phase of vomiting, even a small amount of water may not be tolerated by mouth. Early refeeding may cause re-vomiting in patients, whereas late refeeding may result in dehydration and hypoglycemia. Nil per os (NPO) may be generally recommended by primary physicians, but the appropriate NPO duration for these patients is still unclear.The study aimed to identify the ideal NPO duration for patients with acute vomiting.We prospectively recruited patients with vomiting who underwent NPO management and were administered antiemetic agents in the emergency department (ED) and the pediatric ED. The demographics, final diagnosis, clinical manifestations, medical management, NPO duration, and laboratory data were collected and analyzed to identify the ideal NPO durationA total of 304 patients with vomiting who were admitted in the ED were enrolled. The major diagnosis was acute gastroenteritis (AGE) (82.9%), followed by acute gastritis and colitis. Most patients were younger than 6 years (43.8%). Apart from abdominal pain and vomiting, nausea was the most common symptom (93.1%). NPO duration of 4 to 6 hours had the lowest rate of refeeding failure (3.7%) compared to the other NPO durations.For patients with acute vomiting who are admitted to the ED, NPO duration of 4 to 6 hours may be necessary and should be recommended by primary ED physicians.

Global Gene Expression Analysis of the Brainstem in EV71- and CVA16-Infected Gerbils.

Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are the two most important pathogens of hand, foot, and mouth disease (HFMD). However, the neuropathogenesis of EV71 and CVA16 has not been elucidated. In our previous study, we established gerbils as a useful model for both EV71 and CVA16 infection. In this work, we used RNA-seq technology to analyze the global gene expression of the brainstem of EV71- and CVA16-infected gerbils. We found that 3434 genes were upregulated while 916 genes were downregulated in EV71-infected gerbils. In CVA16-infected gerbils, 1039 genes were upregulated, and 299 genes were downregulated. We also found significant dysregulation of cytokines, such as IP-10 and CXCL9, in the brainstem of gerbils. The expression levels of 10 of the most upregulated genes were confirmed by real-time RT-PCR, and the upregulated tendency of most genes was in accordance with the differential gene expression (DGE) results. Our work provided global gene expression analysis of virus-infected gerbils and laid a solid foundation for elucidating the neuropathogenesis mechanisms of EV71 and CVA16.

p21 is required for atRA-mediated growth inhibition of MEPM cells, which involves RAR.

All-trans retinoic acid (atRA), a metabolite of vitamin A, is essential for embryonic development. Thus the spatial and temporal dispersal of RA must be tightly controlled. Previous studies show that excessive atRA led to growth inhibition and p21 accumulation in mouse embryonic palatal mesenchymal (MEPM) cells. We reported here the identification of p21 as a required mediator during atRA-induced growth inhibition. atRA caused a G1 arrest in the cell cycle with an increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S phase. In addition to a marked effect on cell cycling, atRA also triggered DNA fragmentation, reflected by an increase of the fraction of cells in the sub-G(1) population. Western blot analysis revealed that atRA treatment led to an increase in p21 level and a decrease in cyclin D1 protein and Rb phosphorylation. Using luciferase assay with reporter gene regulated by p21 promoter, we showed that atRA increased the reporter activity in a dose-dependent manner; and p21 siRNA blocked the growth inhibition by atRA, suggesting that p21 is required for atRA-mediated growth inhibition. Moreover, the induction of p21 by atRA was partially attenuated when RAR was silenced with specific siRNA. atRA stimulated RARE-driven reporter gene activity dose-dependently. Using chromatin immunoprecipitation, we demonstrated that RAR protein could bind to the p21 promoter. Taken together, our results indicate p21 is responsible for atRA-induced growth inhibition of MEPM cells and RAR plays a role during this process.

Biodegradable nanocomposite of glycerol citrate polyester and ultralong hydroxyapatite nanowires with improved mechanical properties and low acidity.

Glycerol citrate polyester based on the condensation of glycerol and citric acid has a great potential in biomedical applications owing to biocompatible monomers and biodegradation properties. However, the applications of glycerol citrate polyester are impaired by its poor mechanical properties and high acidity caused by citric acid produced in the degradation process. In this work, a new kind of nanocomposite has been developed using ultralong hydroxyapatite (HAP) nanowires as the "skeleton", and strongly bound glycerol citrate polyester as the "muscle". The ultralong HAP nanowires interweave with each other to form a three-dimensional nanoporous network, and glycerol citrate polyester is homogeneously distributed in the nanoporous network. Owing to the reinforcement of ultralong HAP nanowires, the mechanical properties of the as-prepared nanocomposite are significantly improved compared with the pure glycerol citrate polyester, and the tensile strength even reaches to the level of human cortical bones. Furthermore, the acidity of the aqueous solution after degradation is neutralized by the reaction between citric acid and ultralong HAP nanowires, and the pH value can be stabilized. The as-prepared nanocomposite can solve some problems of the pure glycerol citrate polyester, and shows promising applications in the biomedical field.

[Biocompatibility of bladder extracellular matrix as tissue engineering scaffold].

OBJECTIVE: To investve To investigate the biocompatibility of rabbit bladder extracellular matrix (BECM) and evaluate the feasibility of using BECM as scaffold for reconstruction of tissue engineering urinary tract. METHODS: By the application of associating the solution diosmosis, enzymatic digestion with chemical detergent, the rabbit bladder was decellularized to prepare the BECM, on which rabbit bladder transitional epithelial cells were cultured and seeded in vitro, of which the adhesion and proliferation were observed. MTT method was used to evaluate the cytotoxicity of BECM, which was implanted into the rabbit back for evaluating its histocompatibility meant that the toxicity, degradation and local inflammatory response were studied through gross observation and HE staining. RESULTS: The prepared rabbit BECMs were freeze-drying, and looked like thin semitransparent membrane. By electron microscope examination, there were no residues of cells found on BECM membrane, of which one side had the reticular fibrous structure, and the other side had the compact structure. The co-culture of BECM membrane with bladder transitional epithelial cells indicated that BECM had a good cytocompatibility. The cytotoxicity score tested by MTT method was number 0 and 1. The rabbits in the implant test had no abnormal response. The BECMs degraded gradually in vivo, and growth of peripheral tissue could be seen in the materials after eight weeks. CONCLUSION: The BECMs prepared by our process are cell-free under scanning electron microscopy. Meanwhile, the reticular structure of the tissue matrix is well preserved. The BECMs have the good cytocompatibility with transitional epithelial cells but without cytotoxicity. The BECMs can degrade gradually in vivo with good histocompatibility. BECM is a good bio-derived material of tissue engineering as scaffold for urinary tract reconstruction.

Controlled release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles for direct pulp capping in rat teeth.

Statin at appropriate concentrations has been shown to induce odontoblastic differentiation, dentinogenesis, and angiogenesis. However, using a carrier to control statin release might reduce toxicity and enhance its therapeutic effects. The aim of this study was to prepare poly(d,l-lactide-co-glycolide acid) (PLGA) nanoparticles that contain lovastatin for application in direct pulp capping. The PLGA-lovastatin particle size was determined using dynamic light scattering measurements and transmission electron microscopy. In addition, the release of lovastatin was quantified using a UV-Vis spectrophotometer. The cytotoxicity and alkaline phosphatase (ALP) activity of PLGA-lovastatin nanoparticles on human dental pulp cells were investigated. Moreover, a real-time polymerase chain reaction (PCR) assay, Western blot analysis, and an enzyme-linked immunosorbent assay (ELISA) were used to examine the osteogenesis gene and protein expression of dentin sialophosphoprotein (DSPP), dentin matrix acidic phosphoprotein 1 (DMP1), and osteocalcin (OCN). Finally, PLGA-lovastatin nanoparticles and mineral trioxide aggregate (MTA) were compared as direct pulp capping materials in Wistar rat teeth. The results showed that the median diameter of PLGA-lovastatin nanoparticles was 174.8 nm and the cumulative lovastatin release was 92% at the 44th day. PLGA-lovastatin nanoparticles demonstrated considerably a lower cytotoxicity than free lovastatin at 5, 9, and 13 days of culture. For ALP activity, the ALP amount of PLGA-lovastatin (100 µg/mL) was significantly higher than that of the other groups for 9 and 13 days of culture. The real-time PCR assay, Western blot analysis, and ELISA assay showed that PLGA-lovastatin (100 µg/mL) induced the highest mRNA and protein expression of DSPP, DMP1, and OCN in pulp cells. Histological evaluation of the animal studies revealed that MTA was superior to the PLGA-lovastatin in stimulating the formation of tubular dentin in an observation period of 2 weeks. However, in an observation period of 4 weeks, it was evident that the PLGA-lovastatin and MTA were competitive in the formation of tubular reparative dentin and a complete dentinal bridge.

Direct determination of creatinine based on poly(ethyleneimine)/phosphotungstic acid multilayer modified electrode.

In this work, the direct determination of creatinine was achieved using a poly(ethyleneimine)/phosphotungstic acid multilayer modified electrode with the assistance of Copper(II) ions by cyclic voltammetry. The quantity of creatinine were determined by measuring the redox peak current of Cu(II)-creatinine complex/Cu(I)-creatinine complex. Factors affecting the response current of creatinine at the modified electrode were optimized. A linear relationship between the response current and the concentration of creatinine ranging from 0.125 to 62.5µM was obtained with a detection limit of 0.06µM. The proposed method was applied to determine creatinine in human urine, and satisfied results were gotten which was validated in accordance with high performance liquid chromatography. The proposed electrode provided a promising alternative in routine sensing for creatinine without enzymatic assistance.

Coxsackievirus A16 induced neurological disorders in young gerbils which could serve as a new animal model for vaccine evaluation.

Coxsackievirus A16 (CA16) is one of the major pathogens associated with human hand, foot, and mouth disease (HFMD) in the Asia-pacific region. Although CA16 infections are generally mild, severe neurological manifestations or even death has been reported. Studies on CA16 pathogenesis and vaccine development are severely hampered because the small animal models that are currently available show major limitations. In this study, gerbils (Meriones unguiculatus) were investigated for their suitability as an animal model to study CA16 pathogenesis and vaccine development. Our results showed that gerbils up to the age of 21 days were fully susceptible to CA16 and all died within five days post-infection. CA16 showed a tropism towards the skeletal muscle, spinal cord and brainstem of gerbils, and severe lesions, including necrosis, were observed. In addition, an inactivated CA16 whole-virus vaccine administrated to gerbils was able to provide full protection to the gerbils against lethal doses of CA16 strains. These results demonstrate that gerbils are a suitable animal model to study CA16 infection and vaccine development.

[Repair surgical defect of squamous cell carcinoma of tongue base with advanced patients].

OBJECTIVE: To repair the postoperative tissue detect of the base of tongue cancer in advanced patients. METHOD: There were 30 patients of medium-high differentiation squamous cell carcinoma(SCC) included in this study. According to the TNM staging of AJCC 2002, there were 4 cases of T2N1M0, 7 of T3N1M0, 10 of T3N2M0, 4 of T4N1M0 and 5 of T4N2M0. Surgical approach of the primary lesion: 12 with transhyoidpharyngotomy approach and 18 with mandibulotomy approach. All cases accepted radiotherapy 4-6 weeks after surgery. RESULT: Twenty-five cases were reconstructed with pedicle pectoralis major myocutaneous flaps, and all them survived. Among them, 1 flap was partial split with surrounding tissue spontaneously, and another flap had partial tissue necrosis, however, both flaps grew well with dressing and other local treatment. Other 5 cases were reconstructed with free anterolateral myocutaneous flaps. Among them, 1 flap had partial tissue necrosis, but had a secondary healing after removing necrotic tissue via mouth approach. All 18 patients of larynx-preservation had tracheal tube pulled out. The 3-year survival rate was 68% and the local control rate was 87%. CONCLUSION: Pedicle pectoralis major myocutaneous flaps and free anterolateral myocutaneous flaps were alternative donor area for repairing postoperative tissue defect of the base of tongue; The former was preferred, and the latter was concealed so as to be a kind of effective method, which need adept technique of microsurgery.

[The effect of simulate intraoral sandblasting on the band strength between enamel and composite resin].

OBJECTIVE: To study whether the bond strength between enamel and composite resin could be enhanced by intraoral sand abrasive. METHODS: Ten human maxillary first incisior teeth were divided into 2 groups The experimental group was sandblasted with 30 microm Al2O3 (CoJet-Sand, pressure 300 kPa) from a distance of 5 mm for 5 seconds, and the control group were not sandblasted. The Herculite composite resin composite cylinders were bonded with Coltene system. Bonded specimens were stored in 37 degrees C distilled water for 24 h, then were subjected to shear force in a testing machine. Stress at failure was calculated in Mpa, and mode of failure was recorded. The Student t test was applied to the data. RESULTS: The shear bond strength of experimental groups was (33.0+/-1.8) MPa, and that of control groups was (26.7+/-5.2) MPa,there was significant difference between these two groups. All the adhesive failures happened at the enamel composite resin interface, except that cohesive failure happened in one sandblasted specimen. CONCLUSION: Intraoral sandblasting could significantly enhance the shear bond strength between enamel and composite resin.