Inhibitory Effect of 2R,3R-Dihydromyricetin on Biofilm Formation by Staphylococcus aureus.

The adherence and biofilm formation of Staphylococcus aureus on food contact surfaces are a major concern for the food industry. Development of antibiofilm agents from polyphenols has drawn much attention due to their potent activity. The present study explored the antibacterial and antibiofilm activities of 2R,3R-dihydromyricetin (DMY) against S. aureus ATCC 29213. It was found that DMY exerted excellent antibacterial and bactericidal properties against S. aureus with minimum inhibitory concentration and minimum bactericidal concentration values of 0.125 and 0.25 mg/mL, respectively. Crystal violet staining and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium salt reduction assay demonstrated that DMY significantly reduced the biofilm biomass of S. aureus and decreased the metabolic activity of biofilm cells. Micrographs of light microscope and scanning electron microscope confirmed that DMY inhibited the biofilm formation and caused a disintegration of the complex biofilm architecture. Moreover, DMY was highly efficient in reducing the number of sessile S. aureus cells adhered to stainless steel. These results suggested that DMY could have potential application to control S. aureus contamination in a food processing environment.

Encapsulation of Nucleic Acids into Giant Unilamellar Vesicles by Freeze-Thaw: a Way Protocells May Form.

Protocells are believed to consist of a lipid membrane and encapsulated nucleic acid. As the lipid membrane is impermeable to macromolecules like nucleic acids, the processes by which nucleic acids become encapsulated inside lipid membrane compartments are still unknown. In this paper, a freeze-thaw method was modified and applied to giant unilamellar vesicles (GUVs) and deoxyribonucleic acid (DNA) in mixed solution resulting in the efficient encapsulation of 6.4 kb plasmid DNA and similar length linear DNA into GUVs. The mechanism of encapsulation was followed by observing the effect of freeze-thaw temperatures on GUV morphological change, DNA encapsulation and ice crystal formation, and analyzing their correlation. Following ice crystal formation, the shape of spherical GUVs was altered and membrane integrity was damaged and this was found to be a necessary condition for encapsulation. Heating alone had no effects on DNA encapsulation, but was helpful for restoring the spherical shape and membrane integrity of GUVs damaged during freezing. These results suggested that freeze-thaw could promote the encapsulation of DNA into GUVs by a mechanism: the vesicle membrane was breached by ice crystal formation during freezing, DNA entered into damaged GUVs through these membrane gaps and was encapsulated after the membrane was resealed during the thawing process. The process described herein therefore describes a simple way for the encapsulation of nucleic acids and potentially other macromolecules into lipid vesicles, a process by which early protocells might have formed.

Functionalized PLGA Microsphere Loaded with Fusion Peptide for Therapy of Bone Defects.

The challenges in the treatment of extensive bone defects are infection control and bone regeneration. Bone tissue engineering is currently one of the most promising strategies. In this study, a short biopeptide with specific osteogenic ability is designed by fusion peptide technology and encapsulated with chitosan-modified poly(lactic acid-glycolic acid) (PLGA) microspheres. The fusion peptide (FP) mainly consists of an osteogenic functional sequence (P-15) and a bone-specific binding sequence (Asp-6), which can regulate bone formation accurately and efficiently. Chitosan-modified PLGA with antimicrobial and pro-healing effects is used to achieve the sustained release of fusion peptides. In the early stage, the antimicrobial and soft tissue healing effects can stop the wound infection as soon as possible, which is relevant for the subsequent bone regeneration process. Our data show that CS-PLGA@FP microspheres have antibacterial and pro-cell migration effects in vitro and excellent pro-wound-healing effects in vivo. In addition, CS-PLGA@FP microspheres promote the expression of osteogenic-related factors and show excellent bone regeneration in a rat defect model. Therefore, CS-PLGA@FP microspheres are an efficient biomaterial that can accelerate the recovery of bone defects.

Involvement of the JNK/HO­1/FTH1 signaling pathway in nanoplastic­induced inflammation and ferroptosis of BV2 microglia cells.

Nanoplastics (NPs) are a newly discovered type of environmental pollutant. The potential for neurotoxicity caused by NPs and their mechanisms are unclear. The present study aimed to determine the molecular mechanism underlying neurotoxicity induced by NPs. Microglia (BV2) cells were used for in vitro studies, and it was found that NPs invaded cells, activated inflammasomes, induced the release of significant quantities of inflammatory factors by detection of inflammatory response­associated proteins through Western blot and ELISA. By detection of FITC, SOD, GSH, cellular iron level, and ferroptosis­related proteins, it was found that NPs compromised the anti­oxidative mechanisms of cells, increased intracellular lipid peroxidation and Fe2+ concentration and triggered inflammatory reactions and ferroptosis. Pretreatment with reactive oxygen species (ROS) inhibitor N­acetylcysteine (NAC) alleviated induction of inflammatory reactions and ferroptosis of cells. In addition, inhibiting expression of c­Jun N­terminal kinase (JNK) increased expression of heme oxygenase (HO­1), resulting in decreased ferroptosis, indicating that the JNK/HO­1 signaling pathway was involved in NP­induced effects on ferroptosis in BV2 cells. In conclusion, NPs could induce inflammatory responses and ferroptosis in BV2 cells. JNK/HO­1 mediated ferroptosis may serve an important role in the toxicity of microglia induced by NPs. This study provided novel evidence for the toxic effects of NPs and highlighted a theoretical mechanistic basis for safe prevention and treatment of plastic pollution­induced neurotoxicity.

[Construction and application of an appraisement system of oral surgery difficulty by Delphi method].

PURPOSE: To build an appraisement system of oral surgery difficulty by Delphi method in order to provide basis for evaluation of oral surgery level and performance appraisal methods. METHODS: Delphi method was used to perform two rounds of expert selection, combination of critical value method and synthetical index method was used to select the index, and the weight of the index system was determined by superiority chart. RESULTS: The final evaluation index system of oral surgery difficulty included 4 first-level indexes and 20 second-level indexes. Index evaluation, index meaning and index weight were included in the index system. CONCLUSIONS: The evaluation index system of oral surgery difficulty has its particularity compared with traditional operation index system.

Scientometric Analysis of Dental Implant Research over the Past 10 Years and Future Research Trends.

BACKGROUND: We conducted a bibliometrics analysis to explore the recent trends in dental implant research which could help researchers have a clear grasp of the relevant research hotspots and prospects. Material and Methods. Altogether, 15,770 articles on dental implants, from January 1, 2010, to October 31, 2019, were selected from the Web of Science Core Collection. We used BICOMB software to extract the high-frequency MeSH terms and construct binary and coword matrices. gCLUTO software was used for biclustering and visual analysis, Ucinet 6 software for social network analysis, SCIMAT software for strategic diagram building, Citespace 5.5 software to form timeline visualization, and VOSviewer software, eventually, for bibliometrics cocitation network. RESULTS: Altogether, 72 high-frequency keywords were extracted from the selected articles and 4 clusters and 7 subcategories were identified through biclustering analysis in the dental implant research field. The use of the strategic diagram also enabled us to find the research hotspot and development trends. CONCLUSIONS: The survival rate of dental implants and subsequent restoration have always been the core focus of research. Sinus floor elevation and guided bone regeneration are worthy of constant exploration owing to their reliability. With continuous improvement in technology, immediate loading could become a future research hot spot.

Focused characteristics and effects of light reflected from spherical lipid membrane of giant unilamellar vesicles.

Lipid vesicle is spherical membranous structure with a concave surface on the inside. When a beam of light illuminates a lipid vesicle, the light reflected from the vesicular concave membrane can be focused to have higher intensity and generate enhanced effects. By observing and simulating light reflected from giant unilamellar vesicles (GUVs), the intensity distribution of the light reflected from a spherical concave lipid membrane was investigated. The reflected light had focused characteristics. Its intensity was concentrated 10,000 times and even exceeded the intensity of incident light in a confined region, creating another effective light source in the lipid vesicle. The fluorescence quenching of sulfo-Cy5 encapsulated in spherical GUVs was stronger than that of the outside solution when irradiated by a 632.8 nm laser. When irradiated with ultraviolet light C (UVC), the damage to plasmid DNA encapsulated with spherical GUVs was greater than that of pure plasmid DNA solution and plasmid DNA mixed with lipid membrane fragments. Therefore, in addition to the effects of incident light, the focused light reflected from GUVs could generate incremental effects on encapsulated photoreactive materials if the spherical structure of the lipid membrane was maintained. These results proved that concave lipid membranes of spherical vesicles can focus light and utilize it to generate enhanced effects. The capability of light focusing and its influence on DNA may provide new insights for understanding the function of lipid membranes in cellular life.

A novel large deletion mutation of FERMT1 gene in a Chinese patient with Kindler syndrome.

Kindler syndrome (KS; OMIM 173650) is a rare autosomal recessive skin disorder, which results in symptoms including blistering, epidermal atrophy, increased risk of cancer, and poor wound healing. The majority of mutations of the disease-determining gene (FERMT1 gene) are single nucleotide substitutions, including missense mutations, nonsense mutations, etc. Large deletion mutations are seldom reported. To determine the mutation in the FERMT1 gene associated with a 7-year-old Chinese patient who presented clinical manifestation of KS, we performed direct sequencing of all the exons of FERMT1 gene. For the exons 2-6 without amplicons, we analyzed the copy numbers using quantitative real-time polymerase chain reaction (qRT-PCR) with specific primers. The deletion breakpoints were sublocalized and the range of deletion was confirmed by PCR and direct sequencing. In this study, we identified a new 17-kb deletion mutation spanning the introns 1-6 of FERMT1 gene in a Chinese patient with severe KS phenotypes. Her parents were carriers of the same mutation. Our study reported a newly identified large deletion mutation of FERMT1 gene involved in KS, which further enriched the mutation spectrum of the FERMT1 gene.

Development of poly(N-isopropylacrylamide)/alginate copolymer hydrogel-grafted fabrics embedding of berberine nanosuspension for the infected wound treatment.

In the present study, a novel hydrogel-grafted fabrics embedding of berberine nanosuspension was developed for the treatment of infected wound. Hydrogel-grafted fabric was prepared by graft copolymerization of N-isopropylacrylamide and alginate using ceric ammonium nitrate as initiator. Berberine nanosuspension was prepared and embedded in the hydrogel-grafted fabrics to achieve sustained drug release. The prepared hydrogel-grafted fabrics embedding of berberine nanosuspension was characterized by FT-IR spectroscopy, scanning electron microscopy, and swelling degree studies. Fourier transform infrared spectroscopy revealed that berberine was embedded into the matrix of hydrogel-grafted fabrics, rather than on the surface. Scanning electron microscopy showed that a thin hydrogel layer was formed on the surface of nonwoven fibers. The swelling study showed that hydrogel-grafted fabric had water absorbing characteristic with reversible temperature sensitivity. The drug release study demonstrated that hydrogel-grafted fabrics can be used as a sustained drug delivery system of hydrophobic compounds. The berberine nanosuspension embedded hydrogel-grafted fabric was further investigated in an animal infected wound model and was found to be a very promising wound healing dressing for the treatment and healing of infected wounds.

Development and characterization of an orodispersible film containing drug nanoparticles.

In this study, a novel orodispersible film (ODF) containing drug nanoparticles was developed with the goal of transforming drug nanosuspensions into a solid dosage form and enhancing oral bioavailability of drugs with poor water solubility. Nanosuspensions were prepared by high pressure homogenization and then transformed into ODF containing drug nanoparticles by mixing with hydroxypropyl methylcellulose solution containing microcrystalline cellulose, low substituted hydroxypropylcellulose and PEG-400 followed by film casting and drying. Herpetrione, a novel and potent antiviral agent with poor water solubility that extracted from Herpetospermum caudigerum, was chosen as a model drug and studied systematically. The uniformity of dosage units of the preparation was acceptable according to the criteria of Japanese Pharmacopoeia 15. The ODF was disintegrated in water within 30s with reconstituted nanosuspensions particle size of 280 ± 11 nm, which was similar to that of drug nanosuspensions, indicating a good redispersibility of the fast dissolving film. Result of X-ray diffraction showed that HPE in the ODF was in the amorphous state. In the in vitro dissolution test, the ODF containing HPE nanoparticles showed an increased dissolution velocity markedly. In the pharmacokinetics study in rats, compared to HPE coarse suspensions, the ODF containing HPE nanoparticles exhibited significant increase in AUC0-24h, Cmax and decrease in Tmax, MRT. The result revealed that the ODF containing drug nanoparticles may provide a potential opportunity in transforming drug nanosuspensions into a solid dosage form as well as enhancing the dissolution rate and oral bioavailability of poorly water-soluble drugs.

[Genetic and clinical study on 17 cases of Angelman syndrome with deletion of 15q11-13].

OBJECTIVE: Angelman syndrome (AS) is a neurodevelopmental genetic disorder that maps to 15q11-13. The primary phenotypes are attributable to loss of expression of imprinted UBE3A gene within this region which can arise by means of a number of mechanisms. The purpose of this study was to make a genetic diagnosis and to analyze the clinical features in suspected patients with AS. METHOD: A total of 17 cases were diagnosed clinically as AS including 7 males and 10 females. The age at the time of diagnosis ranged from 8 months to 5 years. Genetic diagnosis was made by methylation-specific PCR (MS-PCR), linkage analysis by short tandem repeat (STR) and chromosome karyotype analysis. According to the international diagnostic criteria of AS, the related characteristic clinical features of the AS patients with deletion of 15q11-13 were analyzed and summarized. RESULT: Deletion of 15q11-13 was confirmed by genetic diagnosis in 17 AS patients. No abnormal findings were observed when they were born. Developmental delay in movement, speech impairments and happy disposition were observed in 100% (17/17) AS patients. And the severe speech deficit was much easier and more obvious to observe than movement. About 80% (14/17) - 90% (15/17) AS patients presented frequent clinical characteristics, such as seizures and abnormal EEG. However, microcephaly could only be observed in 35% (6/17) AS patients. Regarding the associated findings of AS, 41% (7/17) - 77% (13/17) AS patients could be observed with flat occiput/occipital groove, prognathia, wide mouth, wide-spaced teeth, frequent drooling, excessive mouth behaviors, hypopigmented skin, light hair compared to parents, flexed arm position during ambulation and sleep disorder etc. These features occurred at a higher frequency in those patients of > 2 years old group than that of < 2 years old group. CONCLUSION: The testing strategies of MS-PCR and STR linkage analysis combined with chromosome karyotype analysis were appropriate to the molecular genetic diagnosis of AS. In our analysis of clinical features, there was a lower rate of small head circumference (HC) in 35% patients compared with 80% patients in Caucasian with microcephaly, which might be attributable to the phenotypic heterogeneity in different races. And the birth history, movement and speech development and main clinical features of the Chinese AS patients were consistent with those of other studies. Clinical analysis in patients of different age groups showed that findings associated with AS would be more easily observed with the age increasing. Genetic diagnosis should be performed in clinically suspected AS patients.