Practice and experience of standardized management of radiation hygiene in medical institutions / 中国辐射卫生

More than 90% of artificial irradiation comes from medical irradiation. New radiation technologies are constantly emerging in the medical field, bringing benefits to patients. At the same time, the harm of medical irradiation has attracted more and more attention. There are many problems in the supervision and management of radiation health in medical institutions, such as many standards and specifications involved in radiation health in medical institutions, uneven professional ability of personnel in primary health supervision institutions, inadequate implementation of the main responsibility for the safety of radiation diagnosis and treatment in medical and health institutions, and non-standard service of radiation health technical service institutions, etc. In view of the above problems, the implementation plan of standardization of radiation health supervision, radiation diagnosis and treatment behavior, and radiation technical service behavior has been set. After the pilot operation, the effect is obvious.

Quantitative fabrication, performance optimization and comparison of PEG and zwitterionic polymer antifouling coatings.

A versatile fabrication and performance optimization strategy of PEG and zwitterionic polymer coatings is developed on the sensor chip of surface plasma resonance (SPR) instrument. A random copolymer bearing phosphorylcholine zwitterion and active ester side chains (PMEN) and carboxylic PEG coatings with comparable thicknesses were deposited on SPR sensor chips via amidation coupling on the precoated polydopamine (PDA) intermediate layer. The PMEN coating showed much stronger resistance to bovine serum albumin (BSA) adsorption than PEG coating at very thin thickness (∼1nm). However, the BSA resistant efficacy of PEG coating could exceed that of PMEN due to stronger steric repelling effect when the thickness increased to 1.5∼3.3nm. Interestingly, both the PEG and PMEN thick coatings (≈3.6nm) showed ultralow fouling by BSA and bovine plasma fibrinogen (Fg). Moreover, changes in the PEG end group from -OH to -COOH, protein adsorption amount could increase by 10-fold. Importantly, the optimized PMEN and PEG-OH coatings were easily duplicated on other substrates due to universal adhesion of the PDA layer, showed excellent resistance to platelet, bacteria and proteins, and no significant difference in the antifouling performances was observed. These detailed results can explain the reported discrepancy in performances between PEG and zwitterionic polymer coatings by thickness. This facile and substrate-independent coating strategy may benefit the design and manufacture of advanced antifouling biomedical devices and long circulating nanocarriers. STATEMENT OF SIGNIFICANCE: Prevention of biofouling is one of the biggest challenges for all biomedical applications. However, it is very difficult to fabricate a highly hydrophilic antifouling coating on inert materials or large devices. In this study, PEG and zwitterion polymers, the most widely investigated polymers with best antifouling performance, are conveniently immobilized on different kinds of substrates from their aqueous solutions by precoating a polydopamine intermediate layer as the universal adhesive and readily re-modifiable surface. Importantly, the coating fabrication and antifouling performance can be monitored and optimized quantitatively by a surface plasma resonance (SPR) system. More significantly, the SPR on-line optimized coatings were successfully duplicated off-line on other substrates, and supported by their excellent antifouling properties.

Biocompatible and antifouling coating of cell membrane phosphorylcholine and mussel catechol modified multi-arm PEGs.

The design and easy fabrication of biocompatible and antifouling coatings on different materials are extremely important for biotechnological and biomedical devices. Here we report a substrate-independent biomimetic modification strategy for fabricating a biocompatible and antifouling ultra-thin coating. Cell membrane antifouling phosphorylcholine (PC) and/or mussel adhesive catechol (c) groups are grafted at the amino-ends of an 8-armed poly(ethylene glycol). The PC groups are introduced by grafting a random copolymer bearing both PC and active ester groups. The modified 8-arm PEGs (PEG-2c-23PC, PEG-6c-23PC and PEG-8c) anchor themselves onto various substrates from aqueous solution and form cell outer membrane mimetic surfaces. Static contact angle, atomic force microscope (AFM) and X-ray photoelectron spectra (XPS) measurements confirm the successful fabrication of coatings on polydopamine (PDA) precoated surfaces. Real-time interaction results between proteins/bacteria and the coatings measured by surface plasmon resonance (SPR) technique suggest excellent anti-protein adsorption and short-term anti-bacteria adhesion performance. The long-term bacteria adhesion, platelet and L929 cell attachment results strongly support the SPR conclusions. Furthermore, the cell membrane mimetic and mussel adhesive protein mimetic PEG-2c-23PC shows hardly any toxicity to L929 fibroblasts, and the coating surface demonstrates the best anti-biofouling performance. This PDA-assisted immobilization of PC and/or catechol modified multi-arm PEGs provides a convenient and universal way to produce a biocompatible and fouling-resistant surface with tailor-made functions, which hopefully can be expanded to a wider range of applications based on both structure and surface superiorities.

Substrate independent coating formation and anti-biofouling performance improvement of mussel inspired polydopamine.

Mussel inspired polydopamine (PDA) coating has been proven to be a simple and effective method for surface modification of biomaterials. However, the adhesive functional groups remaining on the surface of PDA coating may promote the attachment of nonspecific proteins and microorganisms and hinder anti-biofouling performance. In this study, the PDA coating formation process is monitored in real-time by a sensitive surface plasmon resonance (SPR) technique at different pH values, initial dopamine concentrations and deposition times. The coating morphology is observed by atomic force microscopy (AFM). Nonspecific protein adsorption, platelet and fibroblast cell adhesion, as well as bacteria attachment on the PDA coatings of different thicknesses are measured to evaluate their anti-biofouling performance. Thickness-dependent biofouling of the PDA coatings is demonstrated by the accumulation of adhesive functional groups within the PDA matrix. In order to reduce the biofouling, we treat the PDA coating by FeCl3 coordination, NaIO4 oxidation, heating in air and grafting with a phosphorylcholine copolymer bearing active ester groups. The modified surfaces are characterized by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy measurements. Interestingly, all the treatments help to resist protein adsorption significantly. More excitingly, the simple grafting strategy with a phosphorylcholine copolymer can resist more than 99% of platelet, fibroblast, and bacteria cell attachment, 98% of bovine serum albumin and 95% of bovine plasma fibrinogen adsorption on the PDA coating. These results may find applications in the vast area of surface antifouling, especially for most biomedical devices.

[Effect of six flavor glutinous rehmannis pill in periodontal inflammation therapy].

OBJECTIVE: To observe the effect of clinical therapy of using six flavor glutinous rehmannis pill on chronic adult periodontal inflammation. METHODS: 120 adult patients who have been cured for their periodontitis were selected and divided into two groups randomly. Control group was only treated with SRP (scaling and root planning), and test group was requested to take six flavor glutinous rehmannis pills orally for 5 months after SRP. RESULTS: After taking the medicine for 5 months, RPD (reduction in probing depth) was 0.43 mm, GAL (gain in attachment level) was 0.22 mm and was quite different from the control group (P < 0.01) . CONCLUSION: SRP together with six flavor glutinous rehmannis pill is better than pure SRP in RPD and GAL, it is one kind of taking medicine for improving resistibility and maintenance therapy.

[Restoring ceramo-metal tooth by using self-made crown post-core in order to re-utilize the broken crown of the base tooth].

OBJECTIVE: To explore a new method and its clinical significance of restorative ceramo-metal by using a self-made crown post-core to reutilize the broken crown. METHODS: 18 teeth were restored with ceramo-metal tooth by using self-made crown post-core in order to preserve the old broken base tooth. The patients' own feelings and clinical effect were observed. RESULTS: Followed up for 1-3 years, 83.3% (15 teeth) of the patients were successful. Among the group one was failed because of bad condition of post and caused split of tooth root. The second failure was caused by uneven force by coherent paste uneven. The third failure was caused by tight biting force and caused the tooth broken. CONCLUSION: Restoring ceramo-metal tooth by using self-made crown post-core in order to re-utilize the broken crown of the base tooth is convenient and low cost and is suitable for basic hospitals.