Overview of microplastic pollution and its influence on the health of organisms.

Microplastic pollution has gradually become a major global concern, due to the widespread use of plastics. Microplastics enter the environment and are degradated, while also being ingested by organisms, affecting various physiological functions and adversely affecting the health of organisms. Microplastic pollution is currently a wide concern, but data on the impact on organisms is still not sufficient. Therefore, this review summarizes the research on microplastic pollution in marine, soil and fresh water, and its impact on organisms, focusing on the effects of microplastics on organisms' feeding behavior and oxidative stress responses, intestinal microbes and reproductive function, and the combined effects of microplastic pollutants on organisms. We also summarized the various possible ways of microplastics entering into the human body, and posing a potential threat to human health, which still needs further research.

Comparison of the Effects of 3D Printing Bioactive Porous Titanium Alloy Scaffolds and Nano-biology for Direct Treatment of Bone Defects.

This study was to compare the effects of three-dimensional (3D) printed bioactive porous titanium alloy scaffolds (3DP-BPTAS) and rhBMP-2/PLA-loaded sustained-release nanospheres (SRNs) in the treatment of bone defects. In this study, the bioactive porous titanium alloy scaffolds (BPTAS) with different pore sizes were prepared by selective laser melting (SLM) technology. The rhBMP-2/PLA SRNs were prepared by the double emulsion solvent volatilization method. The morphology of the two nanomaterials was observed under a scanning electron microscope (SEM). The encapsulation rate (ER), drug loading (DL), and in vitro release rate of the SRNs were detected by enzyme-linked immunosorbent assay (ELISA); and the effects of different particle sizes of BPTAS and SRNs on the proliferation of BMSCs were measured using the Methyl Thiazolyl Tetrazolium (MTT) method. 42 healthy male rabbits were selected and rolled into a control group (no treatment), a model group (the femoral condyle defect model), an A800 group (model + 800 µm of BPTAS), and an A1000 group (model + 1000 µm of BPTAS), an A1200 group (model + 1200 µm of BPTAS), an A1500 group (model + 1500 µm of BPTAS), and an SNR group (model + rhBMP-2/PLA SRNs). There were 6 rabbits in each group, and they were sacrificed 4, 8, and 12 weeks after the surgery. They were performed with general observation, X-ray photography, and histological and biomechanical examinations. According to the Lane-Sandhu bone defect repair tissue X-ray and histological scoring standard, the effect of bone defect repair was evaluated. It was found that the actual pore structure of the scaffold prepared by the SLM process was consistent with the theoretical design. The observation under TEM showed that rhBMP-2/PLA SRNs were approximately round, with an average particle size of 835 nm, and its encapsulation efficiency and drug loading rate were 89.02 ± 5.14% and 0.033 ± 0.004%, respectively. The rhBMP-2/PLA SRNs and BPTAS had no statistically obvious increase in the number of cells after cell treatment compared with the control group (P> 0.05). At 12 weeks postoperatively, the stent bone tissue growing distance (SBTGD) in the SRN group was longer than that in the A1000 group (P< 0.01), and that in the A1000 group was better in contrast to the A800, A1200, and A1500 groups (P< 0.01). The Lane-Sandhu X-ray score of the SRN group was better than other groups (P< 0.05). It suggested that 3DP-BPTAS and rhBMP-2/PLA SRNs could repair the bone defects, and rhBMP-2/PLA SRNs were more conducive to the formation of new bone tissue.

The impact of microplastics polystyrene on the microscopic structure of mouse intestine, tight junction genes and gut microbiota.

Microplastics, which are tiny plastic particles less than 5 mm in diameter, are widely present in the environment, have become a serious threat to aquatic life and human health, potentially causing ecosystem disorders and health problems. The present study aimed to investigate the effects of microplastics, specifically microplastics-polystyrene (MPs-PS), on the structural integrity, gene expression related to tight junctions, and gut microbiota in mice. A total of 24 Kunming mice aged 30 days were randomly assigned into four groups: control male (CM), control female (CF), PS-exposed male (PSM), and PS-exposed female (PSF)(n = 6). There were significant differences in villus height, width, intestinal surface area, and villus height to crypt depth ratio (V/C) between the PS group and the control group(C) (p <0.05). Gene expression analysis demonstrated the downregulation of Claudin-1, Claudin-2, Claudin-15, and Occludin, in both duodenum and jejunum of the PS group (p < 0.05). Analysis of microbial species using 16S rRNA sequencing indicated decreased diversity in the PSF group, as well as reduced diversity in the PSM group at various taxonomic levels. Beta diversity analysis showed a significant difference in gut microbiota distribution between the PS-exposed and C groups (R2 = 0.113, p<0.01), with this difference being more pronounced among females exposed to MPs-PS. KEGG analysis revealed enrichment of differential microbiota mainly involved in seven signaling pathways, such as nucleotide metabolism(p<0.05). The relative abundance ratio of transcriptional pathways was significantly increased for the PSF group (p<0.01), while excretory system pathways were for PSM group(p<0.05). Overall findings suggest that MPs-PS exhibit a notable sex-dependent impact on mouse gut microbiota, with a stronger effect observed among females; reduced expression of tight junction genes may be associated with dysbiosis, particularly elevated levels of Prevotellaceae.

[Etiology surveillance of hand-foot-mouth disease in Henan province between 2008 and 2011].

OBJECTIVE: To understand etiological types and distribution features of hand-foot-mouth disease (HFMD) in Henan province between 2008 and 2011. METHODS: A total of 30 486 specimens of feces, rectal swabs or throat swabs from HFMD patients were collected by each Municipal CDC in Henan from 2008 to 2011. The enterovirus 71 (EV71), coxsackie virus A16 (CA16) and other enterovirus (EV) were detected by RT-PCR or real time RT-PCR. The VP1 gene of EV71 was amplified and the sequences were analyzed by bioinformatics software. A genetic evolution tree of the sequence was constructed as well. RESULTS: The positive rates of EV71, CA16 and other EV were 62.70% (11 209/17 876), 12.03% (2150/17 876), 25.27% (4517/17 876) in 17 876 laboratory diagnosed cases, respectively. The differences were statistically significant (χ(2) = 157.17, P < 0.05). The positive rates of EV71, CA16 and other EV were 63.40% (7370/11 624), 11.58% (1346/11 624) and 25.02% (2908/11 624) in male patients and 61.40% (3839/6252), 12.86% (804/6252) and 25.74% (1609/6252) in female patients, respectively. The differences were statistically significant (χ(2) = 4.06, P < 0.05). The children under 5 years old were high-risk population of HFMD, accounting to 97.67% (17 459/17 876) of the laboratory-diagnosed patients.86.92% (15 537/17 876) cases were children between 1 to 3 years old. Constituent ratio of EV71 changed seasonally during a year, there was a high infection ratio of EV71 between April and June, especially in May, the infection ratio reached 69.34% (2384/3438). The positive rates of EV71, CA16 and other EV were 82.48% (5715/6929), 1.76% (122/6929) and 15.76% (1092/6929) among the 6929 laboratory-diagnosed severe cases, respectively. The positive rates of EV71 was higher than CA16 and other EV (χ(2) = 9259.17, 6170.81, P < 0.05, respectively). There were 117 deaths because of severe HFMD, 55 (47.01%) of which were laboratory confirmed. 50 death cases were infected by EV71, and according to the genetic evolution analysis, the VP1 gene of EV71 strain was belonged to subtype C4 of gene C. CONCLUSION: The EV71 and CA16 were the main pathogens which caused HFMD in Henan province, and EV71 virus was the dominant strain, belonging to C4 subtype of gene C.

Neuroprotective Effects of VEGF-A Nanofiber Membrane and FAAH Inhibitor URB597 Against Oxygen-Glucose Deprivation-Induced Ischemic Neuronal Injury.

INTRODUCTION: Brain ischemia is a common neurological disorder worldwide that activates a cascade of pathophysiological events involving decreases in oxygen and glucose levels. Despite substantial efforts to explore its pathogenesis, the management of ischemic neuronal injury remains an enormous challenge. Accumulating evidence suggests that VEGF modified nanofiber (NF) materials and the fatty-acid amide hydrolase (FAAH) inhibitor URB597 exert an influence on alleviating ischemic brain damage. We aimed to further investigate their effects on primary hippocampal neurons, as well as the underlying mechanisms following oxygen-glucose deprivation (OGD). METHODS: Different layers of VEGF-A loaded polycaprolactone (PCL) nanofibrous membranes were first synthesized by using layer-by-layer (LBL) self-assembly of electrospinning methods. The physicochemical and biological properties of VEGF-A NF membranes, and their morphology, hydrophilicity, and controlled-release of VEGF-A were then estimated. Furthermore, the effects of VEGF-A NF and URB597 on OGD-induced mitochondrial oxidative stress, inflammatory responses, neuronal apoptosis, and endocannabinoid signaling components were assessed. RESULTS: The VEGF-A NF membrane and URB597 can not only promote hippocampal neuron adhesion and viability following OGD but also exhibited antioxidant/anti-inflammatory and mitochondrial membrane potential protection. The VEGF-A NF membrane and URB597 also inhibited OGD-induced cellular apoptosis through activating CB1R signaling. These results indicate that VEGF-A could be controlled-released by LBL self-assembled NF membranes. DISCUSSION: The VEGF-A NF membrane and URB597 displayed positive synergistic neuroprotective effects through the inhibition of mitochondrial oxidative stress and activation of CB1R/PI3K/AKT/BDNF signaling, suggesting that a VEGF-A loaded NF membrane and the FAAH inhibitor URB597 could be of therapeutic value in ischemic cerebrovascular diseases.

Bone screws of porous silicon carbide coated with tantalum improve osseointegration and osteogenesis in goat femoral neck fractures.

Traditional metal materials, such as stainless steel and titanium (Ti) alloys, are still the gold standards for fracture fixation. However, the elastic moduli of these materials differ from that of human cortical bone, and the stress shielding effect affects fracture healing, leading to secondary fractures. Herein, a new porous Ta coated SiC (pTa-SiC) scaffold using in internal fixation devices with good mechanical and biological properties was prepared based on porous silicon carbide (SiC) scaffold and tantalum (Ta) metal. The osteogenic and osseointegration properties of the pTa-SiC scaffold were investigated by bothin vitroandin vivotests. The results showed that compared with porous titanium (pTi), the pTa-SiC promoted the proliferation, migration, and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. Moreover, the internal fixation tests were carried out in a goat load-bearing femoral neck fracture model. Histological results showed good osseointegration around the pTa-SiC screws. And the acid etching results showed that bone cells grew tightly on the pTa-SiC throughout bone canaliculi, and the growth mode was contact osteogenesis, which indicated good biological fixation effects. Therefore, it is reasonable to be expected that the new pTa-SiC scaffold with excellent mechanical and biological properties could be a promising candidate for bone implant field.

The generation of void morphology inside soap-free P(MMA-EA-MAA) particles prepared by seeded emulsion polymerization.

Monodisperse soap-free P(MMA-EA-MAA) latex particles were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and methacrylic acid (MAA), and the particles with void morphology were obtained after undergoing alkali post-treatment. Effects of treatment conditions on particle morphology were investigated. Results showed that the void particles can be obtained under the conditions of the temperature >60 degrees C, initial pH >10.0, treatment time >20 min and 2-butanone amount >2.0 ml. The particle volume and the void size increased to the maximum and then decreased with the increases of initial pH and the treatment time, and these two values increased monotonously with the treatment temperature or 2-butanone amount increased. When the treatment temperature was elevated to 90 degrees C, the treatment time was longer than 180 min, or the 2-butanone amount was more than 8.0 ml, the relatively small voids inside most of the particles combined together to form a large one. The void structure disappeared completely as the initial pH was higher than 12.0. The generation mechanism of the void morphology was discussed.

Tantalum coating of porous carbon scaffold supplemented with autologous bone marrow stromal stem cells for bone regeneration in vitro and in vivo.

Porous tantalum metal with low elastic modulus is similar to cancellous bone. Reticulated vitreous carbon (RVC) can provide three-dimensional pore structure and serves as the ideal scaffold of tantalum coating. In this study, the biocompatibility of domestic porous tantalum was first successfully tested with bone marrow stromal stem cells (BMSCs) in vitro and for bone tissue repair in vivo. We evaluated cytotoxicity of RVC scaffold and tantalum coating using BMSCs. The morphology, adhesion, and proliferation of BMSCs were observed via laser scanning confocal microscope and scanning electron microscopy. In addition, porous tantalum rods with or without autologous BMSCs were implanted on hind legs in dogs, respectively. The osteogenic potential was observed by hard tissue slice examination. At three weeks and six weeks following implantation, new osteoblasts and new bone were observed at the tantalum-host bone interface and pores. At 12 weeks postporous tantalum with autologous BMSCs implantation, regenerated trabecular equivalent to mature bone was found in the pore of tantalum rods. Our results suggested that domestic porous tantalum had excellent biocompatibility and could promote new bone formation in vivo. Meanwhile, the osteogenesis of porous tantalum associated with autologous BMSCs was more excellent than only tantalum implantation. Future clinical studies are warranted to verify the clinical efficacy of combined implantation of this domestic porous tantalum associated with autologous BMSCs implantation and compare their efficacy with conventional autologous bone grafting carrying blood vessel in patients needing bone repairing.

The properties of covalently immobilized trypsin on soap-free P(MMA-EA-AA) latex particles.

The covalent immobilization of trypsin onto poly[(methyl methacrylate)-co-(ethyl acrylate)-co-(acrylic acid)] latex particles, produced by a soap-free emulsion polymerization technique, was carried out using the carbodiimide method. The catalytic properties and kinetic parameters, as well as the stability of the immobilized enzyme were compared to those of the free enzyme. Results showed that the optimum temperature and pH for the immobilized trypsin in the hydrolysis of casein were 55 degrees C and 8.5, both of which were higher than that of the free form. It was found that K(m) (Michaelis constant) was 45.7 mg . ml(-1) and V(max) (maximal reaction rate) was 793.0 microg . min(-1) for immobilized trypsin, compared to a K(m) of 30.0 mg . ml(-1) and a V(max) of 5 467.5 microg . min(-1) for free trypsin. The immobilized trypsin exhibited much better thermal and chemical stabilities than its free counterpart and maintained over 63% of its initial activity after reusing ten times.

Aged human cells rejuvenated by cytokine enhancement of biomaterials for surgical ventricular restoration.

OBJECTIVES: This study investigated whether cytokine enhancement of a biodegradable patch could restore cardiac function after surgical ventricular restoration (SVR) even when seeded with cells from old donors. BACKGROUND: SVR can partially restore heart size and improve function late after an extensive anterior myocardial infarction. However, 2 limitations include the stiff synthetic patch used and the limited healing of the infarct scar in aged patients. METHODS: We covalently immobilized 2 proangiogenic cytokines (vascular endothelial growth factor and basic fibroblast growth factor) onto porous collagen scaffolds. We seeded human mesenchymal stromal cells from young (50.0 ± 8.0 years, N = 4) or old (74.5 ± 7.4 years, N = 4) donors into the scaffolds, with or without growth factors. The patches were characterized and used for SVR in a rat model of myocardial infarction. Cardiac function was assessed. RESULTS: In vitro results showed that cells from old donors grew slower in the scaffolds. However, the presence of cytokines modulated the aging-related p16 gene and enhanced cell proliferation, converting the old cell phenotype to a young phenotype. In vivo studies showed that 28 days after SVR, patches seeded with cells from old donors did not induce functional recovery as well as patches seeded with young cells. However, cytokine-enhanced patches seeded with old cells exhibited preserved patch area, prolonged cell survival, and augmented angiogenesis, and rats implanted with these patches had better cardiac function. The patch became an elastic tissue, and the old cells were rejuvenated. CONCLUSIONS: This sustained-release, cytokine-conjugated system provides a promising platform for engineering myocardial tissue for aged patients with heart failure.

[Genomic characteristics of coxsakievirus A16 isolated in Henan Province].

To reveal the genomic sequence characteristics of coxsackievirus A16 (CoxA16) strain isolated from patients with hand-foot-mouth disease (HFMD) in Henan province. A total of 406 samples were detected by reverse-transcription polymerase chain reaction (RT-PCR) and cell-culture-based isolation of coxsackievirus A16. The whole genome of CoxA16 isolate was amplified using 10 pairs of primers, the sequences were analyzed and phylogenetic tree was generated by bioinformatics software. The full length of HN1162/HN/CHN/2010 genome was 7411bp. Compared with the other CoxA16 strains released in GenBank, the nucleotide similarities were 87.0-97.9%, 77.0%-95.4%, 80.3%-96.9%, 77.9% 96.2%, 80.5-100% in 5'UTR, P1, P2, P3, 3'UTR region, respectively; The similarities of nucleotide and amino acid sequences in VP1 region were 91.4%-96.4% and 99.3%-99.7%, respectively. Phylogenetic tree analysis showed that CoxA16 strains isolated from Henan, Shenzhen, Guangzhou and Fujian belonged to the same cluster. The newly isolated CoxA16 from Henan province belonged to subgenotype C2/B-2. These results will have great significance in monitoring CoxA16 and for prevention and control of hand-foot-mouth disease.

[Analysis on clinical and epidemiological characteristics of severe cases infected by EV71].

OBJECTIVE: To explore the clinical and epidemiological characteristics of serious cases of hand-foot-and-mouth disease (HFMD) infected by EV71, in order to provide scientific evidence for prevention and control of HFMD. METHODS: Information was collected by questionaires through consulting medical cases. Data was input by Epidata, and analysed by software SAS 9.13. RESULT: 201 severe cases were investigated. 84.65% of the cases were below 3 years old. The youngest one was 5 months and the oldest one was 8 years old. The ratio for male and female was 2.2: 1.85. 08% of the cases were distributed sporadically. 51.74% of them lived in rural, 29.36% of them lived in urban and 19.9% of them lived at the fringe area of rural and urban. 81.59% of the cases became serious between 1 and 4 days after infected. 100% cases had fever and 99.95% of them had a rash. 96.52% of them had nerve system symptoms. The main complications were virulent spinal encephalitis, pneumonia and breathing exhaustion. 98.01% of the patients were recovered or cured. CONCLUSION: The cases aged below 3 years old are high risk persons. Rural area and the fringe area of rural and urban are the key area for disease control. 1-4 days after onset is the key period to prevent complications.

Immobilization of aminoglycosidic aminocyclitols antibiotic onto soap-free poly(MMA-EA-AA) latex particles.

Monodispersed soap-free poly(MMA-EA-AA) latex particles with surface carboxyl groups were synthesized by emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and acrylic acid (AA) in aqueous medium, and streptomycin sulfate (SMS) was immobilized onto these particles using three different methods. A model experiment was designed to test the feasibility of the reaction between the carboxyl groups of polymer and the amino groups of the medicine. The covalent coupling between the latex particles and the medicine was confirmed by XPS. Results showed that the medicine molecules were located on the particle surface after immobilization, and the coupling efficiency of SMS in pre-adsorption method was higher than that in direct method. The highest coupling efficiency of this medicine was achieved using the spacer-arm method. It was demonstrated that the immobilized medicine had similar antimicrobial activity as the free form using Escherichia coli as an evaluating organism.