Polyethylenimine Nanogels Incorporated with Ultrasmall Iron Oxide Nanoparticles and Doxorubicin for MR Imaging-Guided Chemotherapy of Tumors.

Development of versatile nanoplatforms for cancer theranostics remains a hot topic in the area of nanomedicine. We report here a general approach to create polyethylenimine (PEI)-based hybrid nanogels (NGs) incorporated with ultrasmall iron oxide (Fe3O4) nanoparticles (NPs) and doxorubicin for T1-weighted MR imaging-guided chemotherapy of tumors. In this study, PEI NGs were first prepared using an inverse emulsion approach along with Michael addition reaction to cross-link the NGs, modified with citric acid-stabilized ultrasmall Fe3O4 NPs through 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochloride (EDC) coupling, and physically loaded with anticancer drug doxorubicin (DOX). The formed hybrid NGs possess good water dispersibility and colloidal stability, excellent DOX loading efficiency (51.4%), pH-dependent release profile of DOX with an accelerated release rate under acidic pH, and much higher r1 relaxivity (2.29 mM-1 s-1) than free ultrasmall Fe3O4 NPs (1.15 mM-1 s-1). In addition, in contrast to the drug-free NGs that possess good cytocompatibility, the DOX-loaded hybrid NGs display appreciable therapeutic activity and can be taken up by cancer cells in vitro. With these properties, the developed hybrid NGs enabled effective inhibition of tumor growth under the guidance of T1-weighted MR imaging. The developed hybrid NGs may be applied as a versatile nanoplatform for MR imaging-guided chemotherapy of tumors.

[The cardiovascular protection of irisin and its research progress in sports field].

Irisin is a circulating myokine induced by exercise, which is a cleaved version of fibronectin type III domain containing protein 5 (FNDC5). It can promote the browning of white fat tissue, increase energy consumption, and decrease weight. Irisin plays an important role in the regulation of various diseases, such as diabetes and coronary heart disease. Different types of exercise have different effects on irisin level in blood circulation, and moderate exercise can reduce cardiovascular symptoms. In this paper, the cardiovascular protective effect of irisin and its research progress in the field of exercise are reviewed, hoping to provide a new target for the prevention and treatment of cardiovascular diseases.

Alkyne-functionalized superstable graphitic silver nanoparticles for Raman imaging.

Noble metals, especially gold, have been widely used in plasmon resonance applications. Although silver has a larger optical cross section and lower cost than gold, it has attracted much less attention because of its easy corrosion, thereby degrading plasmonic signals and limiting its applications. To circumvent this problem, we report the facile synthesis of superstable AgCu@graphene (ACG) nanoparticles (NPs). The growth of several layers of graphene onto the surface of AgCu alloy NPs effectively protects the Ag surface from contamination, even in the presence of hydrogen peroxide, hydrogen sulfide, and nitric acid. The ACG NPs have been utilized to enhance the unique Raman signals from the graphitic shell, making ACG an ideal candidate for cell labeling, rapid Raman imaging, and SERS detection. ACG is further functionalized with alkyne-polyethylene glycol, which has strong Raman vibrations in the Raman-silent region of the cell, leading to more accurate colocalization inside cells. In sum, this work provides a simple approach to fabricate corrosion-resistant, water-soluble, and graphene-protected AgCu NPs having a strong surface plasmon resonance effect suitable for sensing and imaging.

Gut microbiota in children with split-dose bowel preparations revealed by metagenomics.

Objective: Split-dose polyethylene glycol (PEG) is routinely used for bowel preparation before colonoscopy. This study aimed to investigate the composition of gut microbiota and its functions in pediatric patients undergoing split-dose PEG bowel preparation for colonoscopy to understand the stability and resilience of gut microbiota. Material and methods: From September to December 2021, 19 pediatric patients were enrolled at Shenzhen Children's Hospital and 76 samples (4 time points) were analyzed using metagenomics. Time points included Time_1 (one day before bowel preparation), Time_2 (one day after colonoscopy), Time_3 (two weeks after bowel preparation), and Time_4 (four weeks after bowel preparation). Result: Alpha diversity comparison at both the species and gene levels showed a decrease in community richness after colonoscopy, with little statistical significance. However, the Shannon diversity index significantly decreased (P<0.05) and gradually returned to pre-preparation levels at two weeks after bowel preparation. The genus level analysis showed six genera (Eubacterium, Escherichia, Intertinibacter, Veillonella, Ruminococcaceae unclassified, and Coprobacillus) significantly different across the four time periods. Additionally, at the species level, the abundance of Escherichia coli, Bacteroides fragilis, and Veillonella parvula significantly increased at one day after colonoscopy before gradually decreasing at two weeks after bowel preparation. In contrast, the abundance of Intertinibacter bartlettii decreased at one day after colonoscopy but then recovered at two weeks after bowel preparation, reaching the preoperative level at four weeks after bowel preparation. Furthermore, five functional pathways (base excision repair, biosynthesis of ansamycins, biosynthesis of siderophore group nonribosomal peptide, flavonoid biosynthesis, and biosynthesis of type II polyketide products) were significantly different across the four time periods, with recovery at two weeks after bowel preparation and reaching preoperative levels at four weeks after bowel preparation. Conclusions: Gut microbiota at the genus level, species level, and functional pathways are impacted in pediatric patients undergoing split-dose PEG bowel preparation and colonoscopy, with recovery two weeks following bowel preparation. However, the phylum level was not impacted. Modifications in gut microbiota composition and function may be investigated in future studies of bowel preparation. This study highlights the stability and resilience of gut microbiota among pediatric patients during bowel preparation.

Enterovirus 71 induces pyroptosis of human neuroblastoma SH-SY5Y cells through miR-146a/ CXCR4 axis.

Enterovirus 71 (EV71) is a predominant causative pathogen of hand-foot-and-mouth disease (HFMD) in children. Compared with other HFMD-associated viruses, EV71 tends to induce more severe neurological complications and even death. However, the detailed mechanism of EV71 causes nervous system disorder is still unclear. In this study, we found that EV71 induced the GSDMD/NLRP3-mediated pyroptosis of SH-SY5Y cells through up-regulated miR-146a. Through bioinformatic analysis, we identified C-X-C chemokine receptor type 4 (CXCR4) as the potential target of miR-146a. We noticed that the expression of CXCR4 was regulated by miR-146a during EV71 infection. Moreover, our results show that over-expression of CXCR4 attenuated EV71-induced pyroptosis of SY-SY5Y cells. These results reveal a previously unrecognized mechanism in which EV71 induces nervous system cells damage through regulating miR-146a/CXCR4 mediated pyroptosis.

[Effects of let-7a on proliferation, osteogenic differentiation and apoptosis of human dental pulp stem cells].

PURPOSE: To study the effect and possible mechanism of let-7a on proliferation, differentiation and apoptosis of human dental pulp stem cell (hDPSCs). METHODS: The cells were divided into four groups: overexpression control (let-7a control/let-7a agomir control), overexpression let-7a (let-7a mimics/let-7a agomir), knockdown let-7a control (let-7a inhibitor control) and knockdown let-7a (let-7a inhibitor). Cell counting kit-8 assay(CCK-8) was used to detect the proliferation of cells at 24 hours, 48 hours and 72 hours after transfection. Calcified nodules were detected by Alizarin red staining. The protein expression of alkaline phosphatase (ALP), osteopontin (OPN), 4E-binding protein 1 (4EBP1), p-4EBP1, mammalian target of rapamycin (mTOR) and p-mTOR were detected by Western blot. Annexin V-APC/7-AAD cell apoptosis detection kit was used to detect the level of apoptosis after transfection. Statistical analysis was performed using GraphPad Prism 5.0 software. RESULTS: Let-7a inhibited proliferation of hDPSCs and promoted odontoblast differentiation and apoptosis. Let-7a down-regulated the expression of 4EBP1, p-4EBP1, mTOR and p-mTOR. CONCLUSIONS: Let-7a may inhibit proliferation of hDPSCs and promote their differentiation and apoptosis by inhibiting mTOR-4EBP1 molecular pathway.

In vitro corrosion resistance and dual antibacterial ability of curcumin loaded composite coatings on AZ31 alloy: Effect of amorphous calcium carbonate.

Rapid corrosion and bacterial infection are obstacles to put into use biodegradable magnesium (Mg) alloy as biomedical materials. In this research, an amorphous calcium carbonate (ACC)@curcumin (Cur) loaded poly-methyltrimethoxysilane (PMTMS) coating prepared by self-assembly method on micro-arc oxidation (MAO) coated Mg alloy has been proposed. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy are adopted to analyze the morphology and composition of the obtained coatings. The corrosion behaviour of the coatings is estimated by hydrogen evolution and electrochemical tests. The spread plate method without or with 808 nm near-infrared irradiation is applied to evaluate the antimicrobial and photothermal antimicrobial ability of the coatings. Cytotoxicity of the samples is tested by 3-(4,5)-dimethylthiahiazo(-z-y1)-2,5-di- phenytetrazoliumromide (MTT) and live/dead assay culturing with MC3T3-E1 cells. Results show that the MAO/ACC@Cur-PMTMS coating exhibited favourable corrosion resistance, dual antibacterial ability, and good biocompatibility. Cur was employed as an antibacterial agent and photosensitizer for photothermal therapy. The core of ACC significantly improved the loading of Cur and the deposition of hydroxyapatite corrosion products during degradation, which greatly promoted the long-term corrosion resistance and antibacterial activity of Mg alloys as biomedical materials.

Mechanical evaluation of decellularized porcine thoracic aorta.

BACKGROUND: Decellularized tissues are expected to have major cellular immunogenic components removed and in the meantime maintain similar mechanical strength and extracellular matrix (ECM) structure. However, the decellularization processes likely cause alterations of the ECM structure and thus influence the mechanical properties. In the present study, the effects of different decellularization protocols on the (passive) mechanical properties of the resulted porcine aortic ECM were evaluated. METHODS: Decellularization methods using anionic detergent (sodium dodecyl sulfate), enzymatic detergent (Trypsin), and non-ionic detergent [tert-octylphenylpolyoxyethylen (Triton X-100)] were adopted to obtain decellularized porcine aortic ECM. Histologic studies and scanning electron microscopy were performed to confirm the removal of cells and to examine the structure of ECM. Biaxial tensile testing was used to characterize both the elastic and viscoelastic mechanical behaviors of decellularized ECM. RESULTS: All three decellularization protocols remove the cells effectively. The major ECM structure is preserved under sodium dodecyle sulfate (SDS) and Triton X-100 treatments. However, the structure of Trypsin treated ECM is severely disrupted. SDS and Triton X-100 decellularized ECM exhibits similar elastic properties as intact aorta tissues. Decellularized ECM shows less stress relaxation than intact aorta due to the removal of cells. Creep behavior is negligible for both decellularized ECM and intact aortas. CONCLUSION: SDS and Triton X-100 decellularized ECM tissue appeared to maintain the critical mechanical and structural properties and might work as a potential material for further vascular tissue engineering.

The effect of microstructure on mechanical properties of corn cob.

As a natural biomass resource, corn cob has excellent mechanical properties and a special layered structure. To investigate the relationship between the mechanical properties and microstructure of corn cob, the ultra-deep field 3D microscope was used to characterize the macro geometric parameters, and the scanning electron microscopy (SEM) was observe the microstructure of the corn cob. The Fourier transform infrared spectrometer was used to analyze the fiber composition, revealing the contribution of fiber composition to the mechanical properties. Axial compression, radial compression, and three-point bending tests were performed on corn cob using a universal testing machine. Moreover, an impact testing machine was used for impact tests. The results show that a corn cob is structurally divided into the pith, woody ring, and glume, mainly composed of cellulose, hemicellulose, and lignin in fiber composition, respectively. The pith is a porous sponge-like tissue that has a greater bearing capacity while maintaining a low density. It is also a progressively hardening material with good buffering properties under impact loads. The woody ring is the primary source of mechanical strength, whose microstructure is a hollow tubular structure composed of cellulose and bonded by lignin. The internal microstructure of the glume is also porous and spongy, but the mechanical properties are mainly manifested in its macrostructure. The results of this study may provide a reference for the subsequent processing and industrial application of corn cob, and the unique structure of corn cob is also an excellent bionic prototype for lightweight design.

[Ultra-fast response polymer optical fiber oxygen measurement device and its preliminary experimental report on continuous dynamic change of arterial oxygen partial pressure under mechanical ventilation in living animals].

Objective: We tried to implant the ultra-fast polymer optical fiber chemical oxygen sensor （POFCOS） into arterial blood vessel,connect with photoelectric conversion measurement system to record the continuous dynamic rapid changes of arterial PO2(PaO2) in whole living animals. It should be the experimental evidence for the new theory of holistic integrative physiology and medicine(HIPM) forexplain the mechanism of respiratory control and regulation in whole circusof respiration-circulation-metabolism. Methods: ①Fabrication of ultrafast POFCOS, calibration and its measuring system: The distal part of 2 m optical fiber was heated and pulled until it became a tapered tip. After cleaning and drying, the tip of 1 mm tapered optical fiber was dip-coated into the luminophore doped polymer solution, then was slowly pumped out while solvent was quickly evaporated to form an oxygen sensing tip, which was dried at room temperature for 24 hours. ②Animal experiments: Under general anesthesia and intubation, goatwas mechanically ventilated with 40%~60% oxygen. We exposed both right and left carotid arteries and the left femoral artery by skin cutting, and inserted the POFCOS directly into the arteries via indwelling catheter. The end of POFCOS were connected to the personal computer through optical fiber, excitation and detection Y-type optical fiber coupler through photoelectric conversion, so as we can realize the continuous dynamic response of living goat carotid PaO2 under mechanical ventilation. We mainly analyzed the intra-breath wave-form alternate increase and decrease of PaO2 and their time delay between lung and carotid arteries.We completes breathing control whole loop to explain the mechanism of mutual breathing and the switching of inspiration and exhalation. Results: The POFCOS has a very fast T90 response time was set 100 ms for liquid. When the heart rate of 40%~60% oxygen mechanical ventilated living goat was ~110 bpm, the PaO2 of left and right carotid artery showed a same wave-sizeup and down following with the inspiration and expiration of ventilator, with a range of up to 15 mmHg. There weresignificant noises of PaO2 change recorded in the left femoral artery. The lung-carotid artery time delay is 1.5~1.7 s after inhalation and exhalation, PaO2 at both left and right carotid arteries starts toincrease and decrease. After two-three heartbeats after the start of lung ventilation, thealternate up-down wave-form information of the arterialized pulmonary vein blood after pulmonary capillaries waspumpedby left ventricle to the position of peripheral chemoreceptors,thus realizing the whole cycle of inhalation and exhalation. It alternately interrupted inhalation, i.e. switching inhalation to exhalation, and then interrupted exhalation,i.e. switching exhalation to inhalation. Conclusion: The ultra-fast reactive implantableoxygen sensor and its measuring system can measure the physiological waveform changes of PaO2 in living animals, which can provide experimental evidence for explaining the mechanism of switching of inspiration-expiration in HIPM.

Synthesis of Ag@CuO nanohybrids and their photo-enhanced bactericidal effect through concerted Ag ion release and reactive oxygen species generation.

Ag and CuO in the form of nanoparticles have been widely used in our daily life as antibacterial agents, through releasing Ag ions and generating reactive oxygen species (ROS). In this work, we demonstrate that by synthesizing Ag@CuO nanohybrids with core-shell configurations, their bactericidal activity can be synergistically enhanced compared to the respective constituents. Upon AM 1.5G light illumination for short durations, the measured minimum inhibitory concentrations of the Ag@CuO nanohybrids show a significant decrease against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacterial strains, requiring only 7% and 34% of those when conducted in the dark. The spread plate results demonstrate that with nanohybrid concentrations of 11.0 and 21.9 mg L-1, at least 7 orders of magnitude decrease in Escherichia coli and Staphylococcus aureus colony forming units is achieved, when the Ag@CuO nanohybrids are exposed to light illumination for 10 min. The effect of illumination is found to induce Ag+ release and enhance 1O2 generation, which act concertedly to facilitate the remarkable photo-enhanced bactericidal effect.

Co-encapsulation of Vitamin C and ß-Carotene in liposomes: Storage stability, antioxidant activity, and in vitro gastrointestinal digestion.

Vitamin C (VC) and ß-Carotene (ßC) were selected to produce co-encapsulated liposomes using hydrophilic and hydrophobic cavities simultaneously by ethanol injection method. The results of liposomal structure characterized by particle size, polydispersity index, zeta-potential and transmission electron microscope showed that the microstructure of all liposomal samples was spherical without adhesion or break and the size of VC-ßC-loaded liposome (L-VC-ßC) was bigger than VC-loaded liposome (L-VC) or ßC-loaded liposome (L-ßC). The encapsulation efficiency (EE) of VC in L-VC-ßC was significantly higher than that in L-VC, and the EE of ßC in L-VC-ßC had no significant change compared with that in L-ßC. The free radical scavenging rate of L-VC-ßC was significantly higher than that of L-ßC, while it had no significant change compared with that of L-VC. In addition, the storage stability of ßC in L-VC-ßC improved greatly compared with that in L-ßC. Furthermore, the zero order model was applied to understand the release kinetics of ßC from L-ßC and L-VC-ßC in the stomach, whereas the Korsmeyr-Peppas model was chosen to describe the release of ßC from two types of liposome in small intestine and their release mechanisms were mainly dominated by Fickian diffusion. It was significant to provide a new idea for using hydrophilic and hydrophobic cavities simultaneously in liposomes to design the multicomponent nutrient delivery system.

Carboxymethylated-bacterial cellulose for copper and lead ion removal.

Carboxymethylated-bacterial cellulose (CM-BC) was synthesized by Acetobacter xylinum by adding water-soluble carboxymethylated cellulose (CMC) in the culture medium. The CM-BC was examined for the removal of copper and lead ions from aqueous solution compared with BC. The effects of performance parameters such as pH, adsorbent dose, contact time on copper and lead ion adsorption were analyzed. Both BC and CM-BC show good adsorption performance at optimized pH 4.5. Compared with BC, CM-BC performs better adsorption, with the value of 9.67 mg (copper)/g, 22.56 mg (lead)/g for BC and 12.63 mg (copper)/g, 60.42 mg (lead)/g for CM-BC, respectively. The adsorption rate closely follows pseudo-second-order rate model and the adsorption isotherm data well follows the Langmuir model.

Polyethylenimine-Based Nanogels for Biomedical Applications.

Nanogels (NGs) are 3-dimensional (3D) networks composed of hydrophilic or amphiphilic polymer chains, allowing for effective and homogeneous encapsulation of drugs, genes, or imaging agents for biomedical applications. Polyethylenimine (PEI), possessing abundant positively charged amine groups, is an ideal platform for the development of NGs. A variety of effective PEI-based NGs have been designed and much effort has been devoted to study the relationship between the structure and function of the NGs. In particular, PEI-based NGs can be prepared either using PEI as the major NG component or using PEI as a crosslinker. This review reports the recent progresses in the design of PEI-based NGs for gene and drug delivery and for bioimaging applications with a target focus to tackle the diagnosis and therapy of cancer.

Corrosion resistance and antibacterial activity of zinc-loaded montmorillonite coatings on biodegradable magnesium alloy AZ31.

A Zinc-loaded montmorillonite (Zn-MMT) coating was hydrothermally prepared using Zn2+ ion intercalated sodium montmorillonite (Na-MMT) upon magnesium (Mg) alloy AZ31 as bone repairing materials. Biodegradation rate of the Mg-based materials was studied via potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and hydrogen evolution tests. Results revealed that both Na-MMT and Zn-MMT coatings exhibited better corrosion resistance in Dulbecco's modified eagle medium (DMEM) + 10% calf serum (CS) than bare Mg alloy AZ31 counterparts. Hemolysis results demonstrated that hemocompatibility of the Na-MMT and Zn-MMT coatings were 5%, and lower than that of uncoated Mg alloy AZ31 pieces. In vitro MTT tests and live-dead stain of osteoblast cells (MC3T3-E1) indicated a significant improvement in cytocompatibility of both Na-MMT and Zn-MMT coatings. Antibacterial properties of two representative bacterial strains associated with device-related infection, i.e. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), were employed to explore the antibacterial behavior of the coatings. The measured inhibitory zone and bacterial growth rate confirmed that Zn-MMT coatings exhibited higher suppression toward both E. coli and S. aureus than that of Na-MMT coatings. The investigation on antibacterial mechanism through scanning electron microscopy (SEM) and lactate dehydrogenase (LDH) release assay manifested that Zn-MMT coating led to severe breakage of bacterial membrane of E. coli and S. aureus, which resulted in a release of cytoplasmic materials from the bacterial cells. In addition, the good inhibition of Zn-MMT coatings against E. coli and S. aureus might be attributed to the slow but sustainable release of Zn2+ ions (up to 144 h) from the coatings into the culture media. This study provides a novel coating strategy for manufacturing biodegradable Mg alloys with good corrosion resistance, biocompatibility and antibacterial activity for future orthopedic applications. STATEMENT OF SIGNIFICANCE: The significance of the current work is to develop a corrosion-resistant and antibacterial Zn-MMT coating on magnesium alloy AZ31 through a hydrothermal method. The Zn-MMT coating on magnesium alloy AZ31 shows better corrosion resistance, biocompatibility and excellent antibacterial ability than magnesium alloy AZ31. This study provides a novel coating on Mg alloys for future orthopedic applications.

[Optimization of matrix formulation of effective parts cataplasm of Pogostemon cablin by uniform design].

OBJECTIVE: To optimize the matrix formulation of the effective part Cataplasm of Pogostemon Cablin. METHOD: The optimal preparation prescription was selected by U17 (17(11)) uniform design,and the tacking strength, cohesive strength and transdermal speed constant were used as test indexes. The equations of three test indexes were established by SPSS. With analysis of the contribution of factors by SPSS regression, the optimal matrix formulation was acquired. RESULT: The optimal matrix formulation is carbopol U10-NoveriteTM7s-glycerine-sorbitol-kaolin-citric acid-aluminum trichloride (1.0:5.0:20:2.0:2.0:0.25:0.2). CONCLUSION: The matrix has good adhesive property, proper drug release rate, desirable hemocompatibility with the extractions of Pogostemon cablin.

Transplantation of adipocyte-derived stem cells in a hydrogel scaffold for the repair of cortical contusion injury in rats.

Adipocyte-derived stem cells have emerged as a novel source of stem cell therapy for their autologous and readily accessible and pluripotent potential to differentiate into different lineages such as neural stem cells (NSCs) and endothelial progenitor cells (EPCs). Transplantation of NSCs and EPCs has been promising for the repair of brain injury. We explored using co-transplanted hydrogel scaffold to improve the survival of the transplanted cells and recovery of neurological function. Adult Wistar rats were transplanted with EPC-hydrogel, NSC-hydrogel, NSC-EPC-hydrogel, EPC only, or NSC only 7 days after cortical contusion injury. Behavioral tests were performed to evaluate neurological function before, and 1, 2, 3, and 4 weeks after transplantation. Size of injury, extent of vascularization, as well as the survival and differentiation of the transplanted EPCs and NSCs, were evaluated at week 5. All transplantation groups displayed significantly better neurological function compared with the control groups. Improved neurological function correlated with significantly smaller injury volumes than that of the saline group. Using immunostaining, we have shown that while transplanted NSCs differentiated into both neurons and astrocytes, the EPCs were incorporated into vessel epithelia. The extent of reactive gliosis (based on glial fibrillary acidic protein immunostaining) was significantly reduced in all treatment groups (NSC-EPC-hydrogel, NSC-hydrogel, and EPC-hydrogel) when compared with the saline group, with the highest reduction in the NSC-EPC-hydrogel transplantation group. Thus, co-transplantation of hydrogel scaffold provides a more conducive environment for the survival and differentiation of NSCs and EPCs at the site of brain injury, leading to improved vascularization and better recovery of neurological function.

[Responses of neurons and astrocytes in rat hippocampus to kainic acid-induced seizures].

OBJECTIVE: To investigate the time course of the responses of neurons and astrocytes in rat hippocampus (HI) to kainic acid (KA)-induced seizures in various regions. METHODS: By means immunohistochemical staining for anti-Fos protein and anti-glial fibrillary acidic protein (GFAP), the regional distribution of reactive neurons and astrocytes in the HI was observed at different time points after a unilateral stereotaxic microinjection of KA into the lateral ventricle of rats to cause limbic and generalized convulsive seizures. RESULTS: The injection of KA triggered limbic motor seizures including immobilization, staring, facial and jaw clonus ect. followed by recurrent generalized convulsive seizures. After KA-induced seizures, the GFAP-positive astrocytes and Fos-positive neurons were markedly increased in the HI. The increase of GFAP immunoreactivity was observed 30 min after the seizure onset, reaching the maximum at 1 h; the increase of Fos immunoreactivity was detected at 1 h after the onset, peaking at 2 h. CONCLUSION: The neurons and astrocytes in rat HI are highly active during seizures and the reactive astrocytes might play an important role in epileptogenesis.

The influence of lifestyle on the incidence of dental caries among 3-year-old Japanese children.

The present cohort study examined how lifestyle, household environment, and caries activity test score of Japanese children at age 1.5 years affected their dental caries incidence at age 3. Inclusion criteria were 1.5-year-old children with no dental caries. Dental examinations were performed for 33,655 children who participated in routine dental examinations at 1.5 years of age, and the exam was repeated approximately 21 months later (at age 3) at the Kobe City Public Health Center in Japan. After excluding 622 children who had caries at age 1.5 and 1831 children with missing lifestyle and household environment data in the questionnaires, the final data analysis was performed on a total of 31,202 children (16,052 boys, 15,150 girls).The multivariate logistic regression analysis indicated a strong association of the consumption of sugar-sweetened beverages/snacks, less frequent tooth brushing by the parents, lack of fluoride varnish, family history of smoking, with the risk of developing dental caries. A child's late bedtime is also one of the major risk factors for dental caries development. Further investigation is needed to examine whether the short duration or the irregularity of the sleep-wake cycle would affect early childhood oral health and whether there is a relationship between late bedtime and late night snack intake.

Improved mesenchymal stem cells attachment and in vitro cartilage tissue formation on chitosan-modified poly(L-lactide-co-epsilon-caprolactone) scaffold.

Considering the load-bearing physiological requirement of articular cartilage, scaffold for cartilage tissue engineering should exhibit appropriate mechanical responses as natural cartilage undergoing temporary deformation on loading with little structural collapse, and recovering to the original geometry on unloading. A porous elastomeric poly l-lactide-co-ɛ-caprolactone (PLCL) was generated and crosslinked at the surface to chitosan to improve its wettability. Human bone marrow derived mesenchymal stem cells (MSC) attachment, morphological change, proliferation and in vitro cartilage tissue formation on the chitosan-modified PLCL scaffold were compared with the unmodified PLCL scaffold. Chitosan surface promoted more consistent and even distribution of the seeded MSC within the scaffold. MSC rapidly adopted a distinct spread-up morphology on attachment on the chitosan-modified PLCL scaffold with the formation of F-actin stress fiber which proceeded to cell aggregation; an event much delayed in the unmodified PLCL. Enhanced cartilage formation on the chitosan-modified PLCL was shown by real-time PCR analysis, histological and immunochemistry staining and biochemical assays of the cartilage extracellular matrix components. The Young's modulus of the derived cartilage tissues on the chitosan-modified PLCL scaffold was significantly increased and doubled that of the unmodified PLCL. Our results show that chitosan modification of the PLCL scaffold improved the cell compatibility of the PLCL scaffold without significant alteration of the physical elastomeric properties of PLCL and resulted in the formation of cartilage tissue of better quality.