Short-term influence of polytetrafluoroethylene micro/nano-plastics on the inhibition of copper and/or ciprofloxacin on the nitrifying sludge activities based on concentration addition and independent action models.

Short-term influence of polytetrafluoroethylene micro/nano-plastics (PTFE-MPs/NPs) on the inhibition of copper (Cu2+) and/or ciprofloxacin (CIP) on the nitrifying sludge activities was explored based on concentration addition (CA) and independent action (IA) models. The half maximal inhibitory concentration (IC50) of Cu2+, CIP, PTFE-MPs (3 µm), and PTFE-NPs (800 nm) on the specific ammonium oxidation rate (SAOR) of nitrifying sludge was 64.57, 51.29, 102.33 and 93.33 mg L-1, respectively, while those on the specific nitrite oxidation rate (SNOR) of nitrifying sludge were 77.62, 32.36, 104.70 and 97.72 mg L-1, respectively. Among the five binary mixtures and two ternary mixtures composed by Cu2+, CIP, and/or PTFE-MPs/NPs, it was found that the two joint inhibitory actions from ternary mixtures on the SAOR and SNOR of the sludge showed time-dependent characteristics by analyzing of CA and IA models, while the five combined inhibitory effects from different binary mixtures did not all have time-dependent features. The two joint inhibition actions from diverse ternary mixtures on the SAOR at the exposure time of 60 min and on the SNOR at 90 min showed always concentration-dependent features, while the combined inhibitions with concentration-dependent characteristics had never been observed in the binary Cu2+ and PTFE-NPs mixtures at different exposure time. The Cu2+, CIP, and PTFE-MPs mixtures (or Cu2+, CIP, and PTFE-NPs mixtures) had synergistic actions on the SAOR at 90 min and antagonistic effects on the SNOR at 60 min based on CA and IA models, and these combined inhibitions did not exhibit concentration-dependent characteristics. In contrast, the joint inhibitory effects (on the SAOR and SNOR) with concentration-dependent features were found in the binary mixtures of CIP and PTFE-MPs at different exposure time, and the join inhibition changed from synergism to antagonism as the increasing concentration of mixed CIP and PTFE-MPs. This study provides novel perspectives for understanding the combined influence of plastic particles with different sizes, antibiotics, and heavy metals on the biological wastewater treatment process.

Development of a machine learning multiclass screening tool for periodontal health status based on non-clinical parameters and salivary biomarkers.

AIM: To develop a multiclass non-clinical screening tool for periodontal disease and assess its accuracy for differentiating periodontal health, gingivitis and different stages of periodontitis. MATERIALS AND METHODS: A cross-sectional diagnostic study on a convenience sample of 408 consecutive subjects was conducted by applying three non-clinical index tests estimating different features of the periodontal health-disease spectrum: a self-administered questionnaire, an oral rinse activated matrix metalloproteinase-8 (aMMP-8) point-of-care test (POCT) and determination of gingival bleeding on brushing (GBoB). Full-mouth periodontal examination was the reference standard. The periodontal diagnosis was made on the basis of the 2017 classification of periodontal diseases and conditions. Logistic regression and random forest (RF) analyses were performed to predict various periodontal diagnoses, and the accuracy measures were assessed. RESULTS: Four-hundred and eight subjects were enrolled in this study, including those with periodontal health (16.2%), gingivitis (15.2%) and stage I (15.9%), stage II (15.9%), stage III (29.7%) and stage IV (7.1%) periodontitis. Nine predictors, namely 'gum disease' (Q1), 'a rating of gum/teeth health' (Q2), 'tooth cleaning' (Q3a), the symptom of 'loose teeth' (Q4), 'use of floss' (Q7), aMMP-8 POCT, self-reported GBoB, haemoglobin and age, resulted in high levels of accuracy in the RF classifier. High accuracy (area under the ROC curve > 0.94) was observed for the discrimination of three (health, gingivitis and periodontitis) and six classes (health, gingivitis, stages I, II, III and IV periodontitis). Confusion matrices showed that the misclassification of a periodontitis case as health or gingivitis was less than 1%-2%. CONCLUSIONS: Machine learning-based classifiers, such as RF analyses, are promising tools for multiclass assessment of periodontal health and disease in a non-clinical setting. Results need to be externally validated in appropriately sized independent samples (ClinicalTrials.gov NCT03928080).

Combined risk factors and risk of upper gastrointestinal cancer mortality in the Linxian general population.

We aimed to explore the association of combined risk factors with risk of death from upper gastrointestinal (UGI) cancer, including esophageal squamous cell carcinoma (ESCC), gastric cardia carcinoma (GCC) and gastric noncardia carcinoma (GNCC) in the Linxian Nutrition Intervention Trial (NIT) cohort. The NIT cohort included 29 584 healthy adults. A combined risk score (CRS) was calculated using a point system method based on 10 risk factors collected at baseline, including gender, smoking, alcohol drinking, body mass index, family history of UGI cancer, drinking tap water, tooth loss and consumption of fresh fruit, eggs and meat. Possible score ranged from 0 to 31, and higher score indicated as poorer health status. Subjects were divided into three groups by the CRS (<12 points, 12 to 20 points and >20 points). The group of CRS <12 points was considered as the reference. During the 30-year follow-up, we identified 4553 UGI cancer deaths. Compared to subjects with a CRS <12 points, the adjusted HRs for CRS of 12 to 20 points and >20 points were 1.69 (95% CI: 1.56-1.83) and 3.06 (95% CI: 2.82-3.33) for UGI cancer mortality, respectively (Ptrend < .001). Comparable associations were also observed for ESCC, GCC and GNCC mortality. Results remained similar across different age groups (Pinteraction > .05). All HRs observed in the second half follow-up period were stronger than that observed in the first half follow-up period. Our study indicated that higher CRS was associated with increased risk of UGI cancer mortality. Appropriate measures should be taken to reduce unhealthy lifestyles.

Systemic administration of choline acetyltransferase decreases blood pressure in murine hypertension.

Acetylcholine (ACh) decreases blood pressure by stimulating endothelium nitric oxide-dependent vasodilation in resistance arterioles. Normal plasma contains choline acetyltransferase (ChAT) and its biosynthetic product ACh at appreciable concentrations to potentially act upon the endothelium to affect blood pressure. Recently we discovered a T-cell subset expressing ChAT (TChAT), whereby genetic ablation of ChAT in these cells produces hypertension, indicating that production of ACh by TChAT regulates blood pressure. Accordingly, we reasoned that increasing systemic ChAT concentrations might induce vasodilation and reduce blood pressure. To evaluate this possibility, recombinant ChAT was administered intraperitoneally to mice having angiotensin II-induced hypertension. This intervention significantly and dose-dependently decreased mean arterial pressure. ChAT-mediated attenuation of blood pressure was reversed by administration of the nitric oxide synthesis blocker L-nitro arginine methyl ester, indicating ChAT administration decreases blood pressure by stimulating nitic oxide dependent vasodilation, consistent with an effect of ACh on the endothelium. To prolong the half life of circulating ChAT, the molecule was modified by covalently attaching repeating units of polyethylene glycol (PEG), resulting in enzymatically active PEG-ChAT. Administration of PEG-ChAT to hypertensive mice decreased mean arterial pressure with a longer response duration when compared to ChAT. Together these findings suggest further studies are warranted on the role of ChAT in hypertension.

Effect of heat treatment on the enzymatic stability of grass carp skin collagen and its ability to form fibrils in vitro.

BACKGROUND: The molecular configuration, molecular weight distribution and thermal transition enthalpy (ΔH) of grass carp skin (GCS) collagens after heat treatment under different conditions were measured using circular dichroism, gel filtration chromatography and differential scanning calorimetry (DSC). The enzymatic stability of collagen was evaluated using different enzymes, while the ability to form fibrils in vitro was assessed by morphological observation of collagen fibrils and turbidity testing. RESULTS: The ΔH values, in-solution molecular aggregation and the stability to enzymatic hydrolysis of GCS collagen decreased irreversibly and progressively with the duration of heat treatment at 33 °C, which was the onset endothermic temperature obtained from the DSC curve. A strong positive linear correlation between the enzymatic sensitivity of collagen and the degree of thermal denaturation was found. A decrease in fibril diameter and D-periodicity length with denaturation could also be observed in the SEM and TEM images. CONCLUSION: The onset endothermic temperature (To ) rather than the denaturation temperature (Td ) is the threshold temperature for configurational stability of GCS collagen in acidic solution, and the biological properties would obviously change if the collagen was heat treated at this temperature.

Electrophoresis-enhanced detection of deoxyribonucleic acids on a membrane-based lateral flow strip using avian influenza H5 genetic sequence as the model.

This study reports a simple strategy to detect a deoxyribonucleic acid (DNA) on a membrane-based lateral flow (MBLF) strip without tedious gel preparation, gel electrophoresis, and EtBr-staining processes. The method also enhances the detection signal of the genetic sample. A direct electric field was applied over two ends of the MBLF strips to induce an electrophoresis of DNAs through the strips. The signal enhancement was demonstrated by the detection of the H5 subtype of avian influenza virus (H5 AIV). This approach showed an excellent selectivity of H5 AIV from other two control species, Arabidopsis thaliana and human PSMA5. It also showed an effective signal repeatability and sensitivity over a series of analyte concentrations. Its detection limit could be enhanced, from 40 ng to 0.1 ng by applying 12 V. The nano-gold particles for the color development were labeled on the capture antibody, and UV-VIS and TEM were used to check if the labeling was successful. This detection strategy could be further developed to apply on the detection of drug-allergic genes at clinics or detection of infectious substances at incident sites by a simple manipulation with an aid of a mini-PCR machine and auxiliary kits.

Efficient adsorptive removal of aminoglycoside antibiotics from environmental water.

Aminoglycoside antibiotics (AGs) in environmental water are emerging pollutants that must be removed to protect human health and the ecosystem. However, removing AGs from environmental water remains a technical challenge due to high polarity, stronger hydrophilicity and unique characteristics of polycation. Herein, a thermal-crosslinked polyvinyl alcohol electrospun nanofiber membrane (T-PVA NFsM) is synthesized and firstly leveraged as the adsorptive removal of AGs from environmental water. The thermal crosslinking strategy is demonstrated to enhance both the water resistance and hydrophilicity of T-PVA NFsM, thereby effectively interacting with AGs with high stability. Experimental characterizations and analog calculations indicate that T-PVA NFsM utilizes multiple adsorption mechanisms, including electrostatic and hydrogen bonding interactions with AGs. As a result, the material achieves 91.09%-100% adsorption efficiencies and a maximum adsorption capacity of 110.35 mg g-1 in less than 30 min. Furthermore, the adsorption kinetics follow the pseudo-second-order model. After eight consecutive adsorption-desorption cycles, T-PVA NFsM with a simplified recycling process maintains a sustainable adsorption capability. Compared with other forms of adsorption materials, T-PVA NFsM has significant advantages such as less consumption of adsorbent, high adsorption efficiency and fast removal speed. Therefore, T-PVA NFsM-based adsorptive removal holds promise for eliminating AGs from environmental water.

Long-term exposure of polytetrafluoroethylene-nanoplastics on the nitrogen removal and extracellular polymeric substances in sequencing batch reactor.

The impact of polytetrafluoroethylene-nanoplastics (PTFE-NPs) on biological sewage disposal was delved, containing nitrogen remotion, microbiological activity and composition of extracellular polymer (EPS). The addition of PTFE-NPs reduced the removal efficiencies of chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) by 3.43 % and 2.35 %, respectively. In comparison with no PTFE-NPs, the specific oxygen uptake rate (SOUR), specific ammonia oxidation rate (SAOR), specific nitrite oxidation rate (SNOR) and specific nitrate reduction rate (SNRR) decreased by 65.26 %, 65.24 %, 41.77 % and 54.56 %, respectively. The PTFE-NPs inhibited the activities of nitrobacteria and denitrobacteria. It was worth noting that, nitrite oxidized bacterium was more resistant to adverse environments than ammonia oxidizing bacterium. Compared with no PTFE-NPs, the reactive oxygen species (ROS) content and lactate dehydrogenase (LDH) grew by 130 % and 50 % under PTFE-NPs pressure. The appearance of PTFE-NPs affected the normal function of microorganisms by inducing endocellular oxidative stress and destroying the completeness of the cytomembrane. The protein (PN) and polysaccharide (PS) levels in loosely bound EPS (LB-EPS) and tightly bound EPS (TB -EPS) increased by 4.96, 0.70, 3.07 and 0.71 mg g-1 VSS, under PTFE-NPs. Meanwhile, the PN/PS ratios of LB-EPS and TB -EPS increased from 6.18 and 6.41-11.04 and 9.29, respectively. The LB-EPS might provide sufficient binding sites for PTFE-NPs adsorption due to its loose and porous structure. The defense mechanism of bacteria against PTFE-NPs was mainly the PN in loosely bound EPS. Moreover, the functional groups referred to the complexation of EPS with PTFE-NPs were mainly related to N-H, CO, and C-N in proteins and O-H in polysaccharides.

Polyvinyl alcohol electrospun nanofiber membrane based solid-phase extraction for monitoring administered aminoglycoside antibiotics in various animal-derived foods.

This work aims to develop a widely applicable method to monitor administered AGs in various animal-derived food samples to ensure food safety. A polyvinyl alcohol electrospun nanofiber membrane (PVA NFsM) was synthesized and employed as solid-phase extraction (SPE) sorbent, in combination with UPLC-MS/MS, for the simultaneous detection of ten AGs in nine types of animal-derived food samples. PVA NFsM exhibited excellent adsorption performance for the targets (with an adsorption rate of over 91.09%), good matrix purification ability (with a reduction of 7.65%-77.47% in matrix effect after SPE), and good recyclability (can be reused 8 times). The method displayed a linear range of 0.1-25000 µg/kg and attained limits of detection for AGs were 0.03-15 µg/kg. Spiked samples demonstrated a recovery of 91.72%-100.04% with a precision of<13.66%. The practicality of the developed method was verified by testing multiple actual samples.

Effect of polytetrafluoroethylene nanoplastics on combined inhibition of ciprofloxacin and bivalent copper on nitrogen removal, sludge activity and microbial community in sequencing batch reactor.

The work aimed to explore effects of polytetrafluoroethylene nanoplastics on joint inhibitions of ciprofloxacin and bivalent copper on the nitrogen removal in a sequencing batch reactor and its potential mechanisms. The addition of bivalent copper and/or ciprofloxacin reduced the ammonia nitrogen elimination rate with or without polytetrafluoroethylene nanoplastics. Adsorption kinetics and thermodynamics showed the binary bivalent copper and ciprofloxacin promoted their adsorptions by polytetrafluoroethylene nanoplastics. Polytetrafluoroethylene nanoplastics enhanced combined toxicities of ciprofloxacin and bivalent copper to sludge activities and microbial community involved into nitrification and denitrification due to the adsorption of ciprofloxacin and bivalent copper by polytetrafluoroethylene nanoplastics. With or without polytetrafluoroethylene nanoplastics, bivalent copper and/or ciprofloxacin caused more obvious level changes of protein than polysaccharide. This study provides novel insights for understanding the effect of combined heavy metals and antibiotics on the performance in a sequencing batch reactor with the nanoplastics stress.

Harnessing Excited-State Proton Transfer Reaction for 2-(6'-Hydroxy-2'-pyridyl)benzimidazole via Solvents.

2-(6'-Hydroxy-2'-pyridyl)benzimidazole (BI), having double functional groups donating protons, is investigated theoretically with an aim to determine the excited-state proton transfer (ESPT) mechanism in different solvents. We demonstrate that the ESPT reaction can take place with the assistance of protic solvents (water and ethanol). At the same time, the vitally important role of bridges of water and ethanol for the ESPT reaction is confirmed by the disappearance of the ESPT reaction when we replaced the protic solvent with aprotic solvent acetonitrile (ACN). We regulate the ESPT reaction of BI via solvents successfully. A different ESPT mechanism from the one proposed previously (the proton of BI transfers from benzimidazole NH to pyridyl nitrogen in ethanol) is proposed. Our simulated potential energy barriers indicate that the ESPT reaction of BI can occur only between the hydroxyl proton and pyridyl nitrogen with the assistance of water or ethanol molecules. We further verify that the water- or ethanol-assisted ESPT reaction of BI is stepwise, and the concerted mechanism is unambiguously ruled out. This systematic investigation into the ESPT mechanism of BI is significant in designing and constructing the desirable supramolecular architectures, which can provide potential supramolecular recognition sites and supramolecular inter- or intra-H-bonding interactions.

Synthesis of boron carbonitride nanosheets using for delivering paclitaxel and their antitumor activity.

As a structural analog of graphene and boron nitride, hexagonal boron carbonitride nanosheets (BCNNSs) are supposed to be a potential drug deliverer. In the present work, an improved solid-state reaction method combined with ultrasonic exfoliating was reported for preparing BCNNSs. Vapor-solid (VS) mechanism was proposed to be responsible for the formation of BCNNSs. The BCNNSs were further modified by DSPE-mPEG-5000 to improve their dispersion in aqueous solution. It was found that the BCNNSs-PEG nanocomplex could be efficiently taken in by MDA-MB-231 breast cancer cells evidenced by inverted fluorescence microscopy. The PEGylated BCNNSs showed an outstanding ability to load paclitaxel through π-π interaction and hydrophobic interaction, and BCNNSs-PEG-loaded paclitaxel presented higher cytotoxicity in comparison with free paclitaxel. BCNNSs may become a promising candidate for delivering paclitaxel and other hydrophobic drugs.

[Silence of VEGFR2 expression mediated by PEI/siRNA complexes].

The aim of this paper is to report the study on gene silencing efficiency of siRNA targeted against mouse VEGFR2 (siVEGFR2) in vitro mediated by polyethyleneimine (PEI) and its anti-tumor effect in vivo. CY3-labeled siRNA was compounded into PEI and transfected into MS1 cells. Confocal microscopy was used to image the subcellular distribution of siRNA in MS1 cells. Semi-quantitative RT-PCR and Western blotting were used to evaluate VEGFR2 gene silencing induced by siVEGFR2/PEI complexes. A tumor-bearing nude mice model was established to compare the anti-tumor effect after delivered by local and systemic routes. siVEGFR2/PEI complex-transfected cells exhibited much fluorescence in cytoplasm with no evidence of nuclear accumulation. The expression levels of VEGFR2 mRNA and protein in PEI-transfected cells were significantly down-regulated compared with that in blank group, the silencing efficiency were 28.2% and 23.6% respectively. The tumor sizes in mice intratumorally injected with siVEGFR2/PEI complexes (189.429 +/- 17.562 mm3) were reduced definitely compared to that in mice injected with siVEGFR2/PEI complexes via vein route (315.507 +/- 20.491 mm3), or to saline groups (365.844 +/- 20.713 mm3). The study demonstrated that PEI could effectively transfect siRNA into cells and silence the VEGFR2 gene expression. Intratumoral delivery is more suitable for non-targeted modified PEI/siRNA complexes to inhibit the tumor growth in vivo. The present data lay a solid foundation to further study on the gene silencing mechanism for PEI-medicated RNAi and its anti-tumor efficiency in vivo.

Comparative Study of 660 and 830 nm Photobiomodulation in Promoting Orthodontic Tooth Movement.

Objective: Photobiomodulation (PBM) can usefully promote wound healing and relieve pain via its biological effects, with a wide range of applications in clinical medicine. The aim of the present study was to investigate the effect of 660 and 830 nm PBM on orthodontic tooth movement. Background data: PBM is based on the biological effects of diode laser irradiation on tissues, promoting cell proliferation and activity. Materials and methods: An orthodontic force was applied to the upper right first molars exposed to a 660 and 830 nm PBM (LHH-500I; Beijing Long Hui Heng Medical Science and Technology Development Corporation) on days 0, 1, 2, 3, 4, 5, and 7 for 50 sec with power density of 0.1 W/cm2 (a beam area of 0.5 cm2, radiate power of 0.05 W), energy density of 5 J/cm2 within 14 days, and a control group with no laser irradiation. Tooth movement was analyzed using a stereomicroscope, the number of osteoclasts determined by tartrate-resistant acid phosphatase (TRAP), and the expression of bone remodeling factors evaluated by immunohistochemistry. Results: The expression of IL-1ß, RANKL, and OPG was significantly stimulated in the 660 and 830 nm groups. The expression of RANKL was significantly higher in the 660 nm group than in the 830 nm group on days 5 and 7; however, there was no significant difference in the expression of OPG and IL-1ß between the 660 and 830 nm groups on days 1, 2, 3, 4, 5, 7, and 14. On days 3 and 5, the number of osteoclasts in the 660 nm group was higher than that in the 830 nm group, and the difference was statistically significant. Tooth movement over 14 days was significantly higher in the 660 and 830 nm groups than in the control group, and there was no significant difference between the 660 and 830 nm groups finally. Conclusions: Both 660 and 830 nm can accelerate the orthodontic tooth movement and promote alveolar bone remodeling on the compression side. Although the difference of tooth movement over 14 days between the two groups was not statistically significant; however, 660 nm PBM to accelerate bone remodeling is stronger than 830 nm PBM at an early stage.

Stable and biocompatible hydrogel composites based on collagen and dialdehyde carboxymethyl cellulose in a biphasic solvent system.

Stable hydrogels with a mechanically strong matrix microenvironment are favorable biomaterials for three-dimensional cell culture. Acidic collagen solution is commonly combined with chemical crosslinkers for rapid network formation. Herein, dialdehyde carboxymethyl cellulose (DCMC) was selected as an optimal crosslinking reagent for its excellent biocompatibility and suitable chemical reactivity. Both shielding of electrostatic attractions between these two oppositely charged biomaterials and obtaining concentrated collagen solution were achieved using a novel biphasic acetic acid /1-ethyl-3-methylimidazolim acetate (AA/[EMIM][Ac]) solvent system. Hydrogel composites containing more crosslinks were obtained by increasing collagen concentrations (5-25 mg/mL), as confirmed by the improved mechanical properties, thermal denaturation temperature, anti-enzymatic ability and compact microstructure. Moreover, cell proliferation assay demonstrated that all the obtained DCMC-crosslinked collagen hydrogel composites ensures commendable biocompatibility. This study provides a promising strategy for manipulating stable and biocompatible hydrogel composites by blending concentrated collagen solution with DCMC in a biphasic solvent system.

Estrone-modified pH-sensitive glycol chitosan nanoparticles for drug delivery in breast cancer.

Estrone-modified glycol chitosan nanoparticles (GCNP-ES) based on the mechanisms of ES-mediated endocytosis and intracellular pH-responsive drug release were developed for the treatment of breast cancer. GCNP-ES were prepared by grafting copolymerization of glycol chitosan with 2-(diisopropylamino)ethyl methacrylate to generate GCNP prior to ES conjugation. The particle size, zeta potential, and paclitaxel (PTX) encapsulation efficiency of GCNP-ES were characterized. In particular, GCNP-ES exhibited pH-responsive dissociation properties while maintaining stability under long-term storage and lyophilization. The drug release of PTX-loaded GCNP-ES (PTX/GNCP-ES) was modestly prolonged with considerable pH sensitivity. GCNP-ES promoted internalization in breast cancer MCF-7 cells by approximately 5-fold as compared to GCNP, and the internalized GCNP-ES was mainly localized in the endosomes of MCF-7 cells. PTX/GNCP-ES exhibited higher cytotoxicity and cell apoptosis ratio than GCNP. In mice with MCF-7 breast cancer xenograft, PTX/GCNP-ES showed higher accumulation at the tumor site, which resulted in a higher tumor inhibition ratio (81.4%) than that achieved by PTX/GCNP (69.4%) and PTX solution (48.8%). Furthermore, no histological and hematological toxicity was detected in in vivo studies of PTX/GCNP-ES. Overall, these results suggested the potential applicability of GCNP-ES as a drug delivery system for breast cancer therapy. STATEMENT OF SIGNIFICANCE: Most breast cancers are hormone dependent. Herein, we developed a estrone-modified glycol chitosan nanoparticles (GCNP-ES) as a drug delivery system to overcome the drawbacks of chemotherpeutic drugs, including poor water solubility and lack of specifity. GCNP-ES could provide efficient drug delivery in breast cancer cells. The study demonstrated that GCNP-ES could dissociate under mildly acidic conditions, leading to the timely payload release of the drug in target tumor cells following internalization. The conjugated estrone of the nanoparticles could significantly increase drug accumulation in the tumor site and result in enhanced therapeutic effect. Thus, the potential applicability of GCNP-ES was suggested.

Experimental and modeling investigation on the rheological behavior of collagen solution as a function of acetic acid concentration.

Systematic analysis of the rheological behavior of collagen solution (10mg/mL) as a function of acetic acid (AA) concentration (0.1-10M) was performed to achieve a deeper understanding about the interaction between collagen molecules and acidic solvent. Steady shear tests showed that all samples exhibited pseudo-plasticity with shear-thinning behavior. Viscosity decreased from 236.448 to 0.792Pa·s at 0.1s-1 suggesting the flow ability of collagen solution improved with increasing AA concentration. Dynamic frequency sweep analysis revealed that the storage modulus, loss modulus, and complex viscosity decreased with the increased AA concentration due to the disentanglement of collagen molecules, while the loss tangent increased. Hysteresis loop areas of collagen solutions were determined by thixotropic measurement, which demonstrated that weaker thixotropic behavior was associated with higher AA concentrations. Furthermore, the ability to resist deformation and elasticity was lower at higher AA concentration. Maximum compliance values increased from 0.042 to 376.407Pa-1, and the recovery percentage decreased from 97.670% to 0.315%. Finally, corresponding mathematical models were employed to simulate and quantitatively assess the experimental data.

Vitamin C plus hydrogel facilitates bone marrow stromal cell-mediated endometrium regeneration in rats.

BACKGROUND: Intrauterine adhesion (IUA) is a common uterine cavity disease which can be caused by mechanical damage that may eventually lead to infertility and pregnancy abnormalities. Since the effect of therapeutic drugs appears disappointing, cell therapy has emerged as an alternative choice for endometrium regeneration. The aim of this study is to investigate whether the combination of hydrogel Pluronic F-127 (PF-127), Vitamin C (Vc), and a bone marrow stromal cell (BMSC) mixture could be a feasible strategy to improve the endometrial regeneration in a mechanical damage model of IUA in rats. METHODS: Firstly, PF-127 cytotoxicity and the effect of Vc was tested in vitro using the Annexin V/propidium iodide (PI) apoptosis test, cell count kit (CCK) growth test, and enzyme-linked immunosorbent assay (ELISA). For the establishment of the rat IUA model, a 2-mm transverse incision in the uterus was prepared at the upper end, and 1.5- to 2.0-cm endometrial damage was scraped. Rats were randomly assigned to five groups to investigate the combined strategy on IUA uterine regeneration: a sham group, an IUA control group, an IUA BMSC encapsulated in PF-127 plus Vc group, an IUA BMSC plus Vc group, and an IUA PF-127 plus Vc group. A cell mixture was injected into the uterine horn while making the IUA model. Eight weeks after cell transplantation, the rats were sacrificed and the uterine was dissected for analysis. Endometrial thickness, gland number, fibrosis area, and the expression of marker proteins for endometrial membrane were examined by hematoxylin and eosin staining, Masson's staining, and immunohistochemistry. RESULTS: Vc promoted the survival and health of PF-127-encapsulated BMSCs in vitro. When this combination was transplanted in vivo, the endometrium showed better restoration as the endometrium membrane became thicker and had more glands and less fibrosis areas. The expression of cytokeratin, von Willebrand Factor (vWF), was also restored. The proinflammatory cytokine interleukin-1ß (IL-1ß) was significantly lower compared with the control group. CONCLUSIONS: Vc alleviates the cytotoxic effect of PF-127 and promotes cell survival and growth in rat BMSC encapsulation. Thus, a cell therapy strategy containing biomaterial scaffold, BMSCs and the modulatory factor Vc promotes the restoration of damaged IUA endometrium.

Preparation and characterization of chitosan/gelatin/PVA hydrogel for wound dressings.

Chitosan (CS)/gelatin (Gel)/polyvinyl alcohol (PVA) hydrogels were prepared by the gamma irradiation method for usage in wound dressing applications. Chitosan and gelatin solution was mixed with poly(vinyl alcohol) (PVA) solution at different weight ratios of CS/Gel of 1:3, 1:2, 1:1, 2:1 and 3:1. The hydrogels irradiated at 40kGy. The structure of the hydrogels was characterized by using FT-IR and SEM. The CS/Gel/PVA hydrogels were characterized for physical properties and blood clotting activity. The tensile strength of CS/Gel/PVA hydrogel enhanced than on the basis of the Gel/PVA hydrogel. The highest tensile strength reached the 2.2Mpa. All hydrogels have shown a good coagulation effect. It takes only 5min for the BCI index to reached 0.032 only 5min when the weight ratio of CS/Gel was 1:1. It means that the hemostatic effect of hydrogels were optimal. And the hydrogrls also showed good pH-sensitivity, swelling ability and water evaporation rate. Therefore, this hydrogel showed a promising potential to be applied as wound dressing.

Combination nonviral murine interleukin 2 and interleukin 12 gene therapy and radiotherapy for head and neck squamous cell carcinoma.

OBJECTIVES: To demonstrate that the combination of nonviral murine interleukin (mIL) 2 and mIL-12 gene therapy and external beam radiation therapy (XRT) have an enhanced therapeutic effect for the treatment of head and neck squamous cell carcinoma (HNSCC) in an orthotopic murine model and to elucidate the mechanism of action. DESIGN: A randomized, controlled study in a murine HNSCC model. INTERVENTIONS: Tumors were established in the floor of the mouth in C3H/HeJ immunocompetent mice with the SCC VII cell line. These tumors were directly injected with single lipid-formulated mIL-2 or single polymer-formulated mIL-12 or a combination of them and with phosphate-buffered saline or vector without mIL-2 and mIL-12 gene as controls. Then the local tumor was radiated twice with a dose of 1 Gy the next day and injected again 4 days later. Antitumor responses, cytokine expression, and natural killer cell and cytolytic T-lymphocyte activity were assayed. Meanwhile, tumor sizes were measured before and after treatment and compared among the different treatment groups and the controls. RESULTS: The combination mIL-2 + mIL-12 + XRT demonstrated a significant increase in antitumor effects compared with single therapy or controls. Increased expression levels of primary and secondary cytokines were found in the group treated with mIL-2 + mIL-12, and this effect was preserved when mIL-2 and mIL-12 treatments were combined with XRT. Combination therapy significantly increased antitumor effects, T-lymphocyte infiltration of CD4(+)and CD8(+), and the numerous necroses compared with monotherapy. CONCLUSIONS: Combination mIL-2 and mIL-12 gene therapy and XRT generates potent antitumor immune responses against HNSCC and significantly increases necrosis (apoptosis) in an orthotopic murine model of HNSCC. The nonviral mIL-2 and mIL-12 gene delivery system was well tolerated. Further optimization of treatment strategy for patients with HNSCC is warranted as well as consideration for human clinical trials.