复方熊胆眼药水对实验性兔角膜白斑的疗效观察

本实验根据中医学对角膜瘢痕的认识以及历代中医应用中药熊胆治疗角膜翳的理论和方法,配制了复方熊胆眼药水.通过复方熊胆眼药水对实验性兔角膜白斑的疗效观察和光镜下兔角膜病理形态学检查,结果提示复方熊胆眼药水有显著的退翳作用,探讨该作用是通过消除角膜的慢性炎症,增加其局部组织代谢来实现的.指出复方熊胆眼药水对临床角膜瘢痕患者的治疗及角膜移植术前的辅助治疗是有积极意义的.     

Risk of Incident Atrial Fibrillation With Zoledronic Acid Versus Denosumab: A Propensity Score–Matched Cohort Study

Zoledronic acid (ZA) is an effective agent in osteoporosis and malignancy-related bone disease but may be associated with increased risk of atrial fibrillation (AF), although current studies disagree on this risk. To examine the risk of incident AF among patients receiving ZA compared with denosumab in the first year of treatment, we performed a new-user, active comparator cohort study including privately insured Americans between January 1, 2010, and June 30, 2019. Individuals aged ≥50 years without known arrhythmia or advanced kidney disease who initiated ZA were 1:1 propensity score (PS)-matched to individuals initiating denosumab in separate osteoporosis and malignancy cohorts. The primary outcome was incident diagnosis of AF (≥ 1 inpatient or ≥ 2 outpatient diagnostic codes) over 1 year. Secondary outcomes included stroke/transient ischemic attack (TIA) and nonvertebral fracture. In the osteoporosis cohort (n = 16,235 pairs), mean age was 71 years, and 93% were female. There was higher risk of AF with ZA compared with denosumab over 1 year (incidence rate [IR] = 18.6 versus 14.9 per 1000 person-years; hazard ratio [HR] = 1.25; 95% confidence interval [CI] 1.04 to 1.50). In the malignancy cohort (n = 7732 pairs), mean age was 70 years, and 66% were female. There was a numerically higher, albeit not statistically significant, risk of AF with ZA compared with denosumab over 1 year (IR = 46.9 versus 39.0 per 1000 person-years; HR = 1.19; 95% CI 1.00 to 1.43; p = 0.06). No difference in stroke/TIA rates occurred. In the malignancy cohort, ZA was less effective than denosumab at preventing nonvertebral fractures (HR = 1.32; 95% CI 1.01 to 1.74). Compared with denosumab, ZA treatment for osteoporosis and possibly for malignancy-related bone disease is associated with modestly increased risk of incident AF in the first year of treatment. © 2020 American Society for Bone and Mineral Research (ASBMR).     

Electrochemical fabrication of conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) nanofibrils on microfabricated neural prosthetic devices

This paper describes methods for electrochemically polymerizing conducting polymer poly(3,4-dioxyethylenethiophene) (PEDOT) nanofibrils on microfabricated neural prosthetic devices from aqueous solutions containing polyacrylic acid (PAA). These fibrils have characteristic sizes ranging from 100 to 1000 nm in diameter, depending on the concentration, molecular weight of PAA and thickness of the film. The PEDOT nanofibril-coated electrodes have significantly lower electrical impedance due to their higher effective surface area. We propose a mechanism of nanofibril formation involving locally anisotropic variations in EDOT monomer transport and PEDOT film growth due to segregation of the PAA counter-ions. This deposition method provides an improvement in the electrical properties by increasing the effective surface area of the electrodes, while still maintaining the overall small electrode size. It is also opens up new reliable and reproducible strategies for the direct electrochemical polymerization of conducting polymer nanofibrils on a variety of electrodes.     

Poly(hydroxyethyl methacrylate-co-methacrylamidoalanine) membranes and their utilization as metal-chelate affinity adsorbents for lysozyme adsorption

Different adsorbents have been reported in the literature for protein purification. The authors have developed a novel and new approach to obtain high protein adsorption capacity utilizing a 2-methacrylamidoalanine-containing membrane. Amino acid ligand 2-methacrylamidoalanine (MAAL) monomer was synthesized using methacryloyl chloride and alanine. Poly(2-hydroxyethylmethacrylate-co-2-methacrylamidoalanine) [p(HEMA-co-MAAL)] membranes were then prepared by UV-initiated photopolymerization of HEMA and MAAL in the presence of an initiator (azobisisobutyronitrile, AIBN). The synthesized MAAL monomer was characterized by NMR. p(HEMA-coMAAL) membranes were characterized by swelling studies, porosimeter, SEM, FTIR, and elemental analysis. These membranes have macropores in the size range of 5-10 μm. Cu(II) ions (25.9 mmol/m²) were chelated on these membranes. p(HEMA-co-MAAL) membranes were used to study the adsorption of lysozyme from aqueous media containing different amounts of lysozyme (0.1-3.0 mg/l) and at different pH values (4.0-8.0). The non-specific adsorption of lysozyme on the pHEMA membranes was negligible (0.9 μg/cm²). Incorporation of MAAL increased the lysozyme adsorption significantly up to 2.96 mg/cm². The lysozyme adsorption capacity of the Cu(II) incorporated membranes (9.98 mg/cm²) was greater than that of the p(HEMA-co-MAAL) membranes. More than 90% of the adsorbed lysozyme was desorbed in 1 h in the desorption medium containing 1.0 M NaCl and 0.025 M EDTA. The metal-chelate affinity membranes are suitable for repeated use for more than ten cycles without a noticeable loss of capacity.     

Interaction of 2-(9H-purin-6-ylamino)-4-(methylthio) Butanoic Acid with Human Serum Albumin: Fluorescence and Modeling Studies

This study was designed to investigate the interaction between (S)-2-(9H-purin-6-ylamino)-4-(methylthio) butanoic acid (PYMBA) and human serum albumin (HSA) using fluorescence spectroscopy. The combination of UV absorption and molecular docking under simulative physiological conditions was also applied to comprehensively understand the binding mechanism of PYMBA to HSA. Fluorescence data indicated that PYMBA has a strong ability to quench the intrinsic fluorescence of HSA. The binding constants (K) at different temperatures, thermodynamic parameters including enthalpy change (ΔH) and entropy change (ΔS) of PYMBA–HSA were correlated to the relevant fluorescence data, which suggested that the hydrophobic force played a very important role for the PYMBA binding to the HSA. The experimental results were in agreement with the results obtained via a molecular docking study. The effects of other ions on the binding constants were also studied.     

Release of aqueous calcium and phosphate from human dental enamel following administration of self-etching adhesives

Seven self-etching adhesives were studied on an experimental reconstituted human enamel model. The objective was to evaluate the acid dissociation step of the enamel minerals. The self-etching products were applied to the enamel specimens according to the manufacturers' instructions and then rinsed with distilled water. The aqueous calcium and phosphate released were analysed chemically by atomic absorption and ion chromatography, respectively. Results show widely varying concentrations related to pH, acid concentration and calcium binding capacity. All concentrations are less than reference values obtained with orthophosphoric acid. The effectiveness of self-etchants is discussed in terms of their ability to demineralise human enamel and incorporate the released ions in the subsequent HEMA co-polymer composing the hybrid layer.     

The MPEG Monophosphate Ester: Synthesis and Characterization

Methods of preparation of the phosphoric ester of monomethyl ether of poly(ethylene glycol) (MPEG-P) from MPEG (M _n = 550 and 2000) and phosphoric acid (P), or its derivatives — pyrophosphoric acid (PY), polyphosphoric acid (PP) and POCl₃– are described and compared. MPEG-P was isolated in a pure state (no detectable impurities) and characterized.     

A Novel GAP460 Biopolymer for Use as a Carrier in Drug-Delivery Applications

We synthesized a new non-toxic biopolymer (GAP460) containing γ,L-glutamic acid and aspartate (Asp). Conjugates of GAP460 and cisplatin exhibited a drug-carrying capacity of nearly 40%, 3-times higher than γ-PGA and dramatically decreasing the amount of biopolymer required for high-dose delivery. Treatment with GAP460-cisplatin conjugate (PACC) not only effectively inhibited tumor growth in nude mice, but also resulted in extended survival and lower nephrotoxicity, suggesting that GAP460 could be used as an effective carrier for drug delivery and that PACC may have potential therapeutic applications in the clinical treatment of cancer.     

Modulating the Activities of Human Mesenchymal Stem Cells (hMSCs) and C3A/HepG2 Hepatoma Cells by Modifying the Surface Characteristics of Poly(3-hydroxybutyrate-co-3-hydroxyhexnoate) (PHBHHx)

The new biodegradable polyester poly(3-hydroxybutyrate-co-3-hydroxyhexnoate) (PHBHHx) has a potential application in tissue engineering. The aim of this study was to present a deeper picture of the relationship between the cellular behavior and the surface characteristics of PHBHHx films. The pristine PHBHHx film was prepared by adopting the compression-molding method, and then the acrylic acid molecules were grafted on PHBHHx membrane surface by UV irradiation. The hydrophilic nature and surface roughness of various PHBHHx films were controlled by adjusting the acrylic acid concentration and the UV irradiation time. Although the surface characteristics of various PHBHHx films could not affect the metabolic activity of hMSCs, the performance of morphology of hMSCs was deeply affected by the hydrophilic nature and the orientation of surface scars. The hydrophilic nature would effectively improve the spread of hMSCs, and the orientation of surface scars would guide the growth direction of cytoskeleton (actin) inside hMSCs. In contrast, the behaviors of C3A/HepG2 hepatoma cells presented an opposite outcomes. Those surface characteristics were obviously associated with the performance of metabolic activity of C3A cells, but not with the morphology of C3A cells. Both hMSCs and C3A cells have unique cellular characteristics; therefore, their responses to environmental stimulations are significantly different.     

Bioactive functionalized polymer of malic acid for bone repair and muscle regeneration

A bioactive poly(β-hydroxyalkanoate) derived from malic acid was prepared and tested on bone repair and muscle regeneration. This functionalized and hydrolyzable polymer was obtained after several steps, the first one being the anionic copolymerization of three malolactonic acid esters. Chemical modifications were carried out on the terpolymer to turn benzyl-protecting groups into carboxyl groups and allyl groups into sulfonate groups. The resulting polymer bore carboxylate, sulfonate, and sec-butyl pendent groups in 65/25/10 molar proportions and were aimed at interacting with heparan binding growth factors. This polymer did not present any toxic effect in cell viability of HepG₂ cells, over a large range of concentrations (0.01-0.25 mg l^-1). Its ability to improve wound healing was tested in vivo and positive results are reported. Furthermore, the bioactivity of this polymer was evaluated using the regeneration model of Extensor digitorum longus (EDL) rat muscle. The study displayed a significant increase in the muscle regeneration and maturation.