Effects of Heat Treatment Conditions on Shape Memory Recovery of NiTi Self-expanding Vascular Stents / 中国医疗器械杂志

Effects of heat treatment conditions (including temperature and time) on the shape memory recovery and corrosion resistance of NiTi self-expanding vascular stents were studied based on working mechanism and clinical use. The

Progress in respiratory toxicity of polyhexamethyleneguaidine disinfectant and mechanism exploration / 中华预防医学杂志

Polyhexamethylene guanidine (PHMG) is a high molecular guanidine compound with a broad spectrum of antibacterial effects. Since the outbreak of the 'humidifier disinfectant-induced lung injury’ event in South Korea, the respiratory toxicity of PHMG had become a public concern. An epidemiological survey in Korea found that PHMG-containing disinfectants were an important risk factor for pulmonary fibrosis. Animal experiments also showed that the exposure to PHMG through the respiratory tract could cause irreversible fibrosis in the lungs. TGF-β signaling pathway, epithelial-mesenchymal transition and pulmonary inflammation might be the main pathways that could mediate PHMG-induced pulmonary fibrosis. This article provided an overview of the characteristics of population exposure to PHMG and research progress in the field of respiratory toxicology and recommendations for the rational and standard of using PHMG-related products in China.

Study on fibrosis changes in the lungs of mice caused by repeated inhalation of polyhexamethyleneguaidine disinfectant / 中华预防医学杂志

Objective@#To explore the lung damage caused by repeated inhalation of polyhexamethyleneguanidine (PHMG) disinfectant aerosol and the corresponding toxicological characteristics.@*Methods@#Thirty four-week-old mice of C57BL/6N strain were randomly divided into three groups, the control group, low-dose group, and high-dose group. Each group had 5 male mice and 5 female mice. Lab II-level purified water was used in the control group. The PHMG disinfectant aerosol was generated by using the ultrasonic atomization of the aqueous solution containing PHMG. The PHMG concentrations in the low-and high-dose groups were 0.1 mg/ml (0.01%) and 1 mg/ml (0.1%), respectively. The concentration of PHMG in the post-chemical exposure room was 1.03 mg/m3 and 9.09 mg/m3 according to the air sampler analysis. The experimental mice were exposed to the PHMG in dynamic respiratory exposure mode for 4 hours every day in 21 days. After 21-day exposure, bronchia alveolus lung fluids (BALFs) were used to evaluate the inflammatory cells in the lungs, and pathological evaluation, special staining and immunohistochemical methods were further performed to evaluate the key indicators of pulmonary fibrosis.@*Results@#Compared to the control group, the body weight of mice in the high-dose group was significantly decreased (P<0.05), while that of mice in the low-dose group did not significantly differ (P>0.05). The number of inflammatory cells in BALFs of low-dose exposed mice was slightly reduced, and the lung tissue pathology began to show lung damage with early fibrosis symptoms (P<0.05). The pathological examination of mice in the high-dose group showed changes in pulmonary fibrosis. Immunohistochemical staining showed that pulmonary fibrosis marker, α-SMA, was significantly increased in low-dose group and high-dose group (P<0.05).@*Conclusion@#The repeated inhalation of PHMG disinfectant could cause lung damage such as pulmonary fibrosis in mice. It could suggest that special warnings should be given to this common disinfectant and respiratory protection measures should be adopted during industrial production and daily use.

Study on the 3,4-Dihydroxyphenylalanine Redox State Characterization Method of Mussel Adhesive Protein / 中国医疗器械杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of using liquid chromatography (HPLC) to characterize the 3, 4-Dihydroxyphenylalanine (DOPA) redox state of mussel adhesive protein (MAP).</p><p><b>METHODS</b>The DOPA and protein contents of MAP were determined by HPLC, Arnow and Bradford methods respectively.</p><p><b>RESULTS</b>With extended oxidation time, the protein contents of MAP samples remained unchanged whereas the DOPA contents declined. The retention times of main peaks in HPLC for both the accelerated oxidation and retained samples shifted as the storage time extended, which could be related to the changes of sample redox state.</p><p><b>CONCLUSIONS</b>The redox state of MAP can be characterized by the change of HPLC peak retention time. HPLC can be used in the research on the MAP redox state, which is beneficial to the product development and quality control.</p>

A Preliminary Study on the Classification Regular Pattern of Non-Powered Suction Apparatus Device Intended for Negative Pressure Wound Therapy / 中国医疗器械杂志

The classification messages of non-powered suction apparatus device (NPSAD) intended for negative pressure wound therapy by CFDA have been analysis and generalized. A set of classification regular patterns of NPSAD have been generalized from its intended use, composition, mechanism, contact area and resorbable characteristic. It is helpful to draw a more consistent classification in NPSAD.

Research on the treatment of liver failure rats with transplantation of alginate microencapsulated hepatocytes in vivo based on poly-ornithine / 生物医学工程学杂志

This study aims to explore the effects of alginate-poly ornithine-alginate (A-PLO-A) and barium alginate-poly ornithine-alginate (B-PLO-A) microcapsules as cells carriers during implantation. Mice hepatocytes coated in A-PLO-A and B-PLO-A microcapsules were implanted into rats with acute liver failure caused by intraperitoneal injection of D-galactosamine. The rat survival rate, liver cell growth, proliferation and metabolism within the microcapsules were investigated, as well as its effect on the improvement of rat acute liver failure. The influence of A-PLO-A-free microcapsules, B-PLO-A-free microcapsules, isolated liver cells, A-PLO-A microcapsule-coated and B-PLO-A microcapsule-coated liver cells was studied. It was found that the chemical-free microcapsules showed no positive effect on the rats with liver failures, with a death rate of 100% in both groups 3 days after the implantation. The ALT, AST and ALB levels were all improved in the isolated liver cell group, the A-PLO-A microcapsule-coated and the B-PLO-A microcapsule-coated groups. The survival rate of both microcapsule-coated liver cell groups was significantly higher than that of the chemical-free microcapsule group and the isolated liver cells group. The microcapsules were retrieved after 4 weeks' implantation, which were observed to be smooth with no cells attaching to the surface. No apparent fibrosis was observed. This research demonstrated the physical stability and the biocompatibility of the PLO-based alginate microcapsules and therefore they could be used as liver cell carriers during implantation.

Preliminary study of a new heart valve prostheses implanted with minimally invasive techniques: pulsatile-flow testing in vitro / 生物医学工程学杂志

The aim of this study was to investigate the pulsatile-flow performance in vitro of a new heart valve prostheses implanted with minimally invasive techniques (HVPMIT). Three HVPMITs were tested valves and another three original biological heart valve prostheses acted as reference valves. The pulsatile-flow parameters (including mean pressure drop, regurgitant percentage of stroke volume, and effective orifice area) were tested in a pulse duplicator according to the methods listed in ISO5840-2005 and GB 12279-2008. The results demonstrated that the regurgitant percentage of stroke volume of tested valves was up to 13%. It was significantly higher than that of the reference valves. This result suggested that paravalvular leakage had occurred in the tested valves. It was found in the further analysis that because HVPMIT was not sewn into the heart tissue when the HVPMIT was implanted in vivo and there was not a sewing ring in the HVPMIT, when tested valves were fixed in the pulse duplicator, some gaps might exist between the stent of HVPMIT and the fix gasket, and the paravalvular leakage could therefore take place through these gaps. This study demonstrated that there are significant differences in the shape, structure, fixation in vivo and clinical operational methods between HVPMIT and original biological heart valve prostheses. It is necessary to establish new test methods which adapt for HVPMIT to evaluate its pulsatile-flow performance according to its own features.

The effect of buyanghuanwu decoctinn on expression of immunoreactive protein and mRNA of NMDA receptor 2B subunit in rats hippocampal with vascular dementia / 中华行为医学与脑科学杂志

Objective To observe the effect of buyanghuanwu decoction on expression of immunoreactive protein and mRNA of NMDA receptor 2B subunit in rats hippocampal with vascular dementia to investigate the mechanism of buyanghuanwu decoction. Methods One hundred and forty-four rats were randomly divided into 4 groups: sham-operated group, VD model group,nimodipine group and buyanghuanwu decoction treatment group. The rats models of vascular dementia were built up by four vessels occlusion method. VD rats were treated with in-tragastrical buyanghuanwu decoction suspension (50 pharmacognostic g·kg-1·d-1) and nimodipine suspension (20 mg·kg-1·d-1) for 30 days. The learning and memory abilities were evaluated by Morris water maze tests. The change of NR2B protein in hippocampal of each group of rats were measured with immunohistochemistry and Western blot techniques and the expression of NR2B mRNA in hippocampus were observed by real-time fluorescence quantitative PCR techniques. Results Water maze tests,compared with sham-operated group((24. 18 ± 7.90)s,(7.99 ±1.32)/min) ,the escape latency(51. 25 ±18.28)s to explore the extension and the average spatial probe number ((5. 26 ±0. 74)/min) reduced in VD model group (P < 0. 05). Buyanghuanwu decoction ((25.91 ±9.56)s,(7. 52 ± 1. 27)/min) had significantly improved the above-mentioned rat model of learning and memory performance (P<0.05). There was no significant difference among sham-operated group,nimodipine group and buyanghuanwu decoction treatment group (P>0. 05). Similarly,as compared rats with sham-operated group(0.71 ±0.13), (5887 ±501), the expression of NR2B protein (0. 33 ± 0. 06) and its mRNA(593 ±53) were apparently decreased in VD rats (P< 0.05). The expression of NR2B protein(0.66 ±0. 11) and its mRNA (5692 ±482) in neuron of hippocampus were increased by buyanghuanwu decoction compared with the model group (P < 0. 05), and no difference was discovered between sham operation group and nimodipine group (P > 0.05).Conclusions Buyanghuanwu decoction improves the learning and memory abilities in VD rats, the therapeutic mechanism was concerned with lessening the injury of neurons on CA1 field in hippocampus and promoted the expression of NR2B protein and its mRNA.

Status of biological evaluation on silver nanoparticles / 生物医学工程学杂志

Silver nanoparticles have been widely used in medicinal and biological fields. Their biological evaluation is an important researchful field. In this paper are summarized the status quo of nano-hydroxyapatite biological evaluation at home and abroad. Although silver nanoparticles showed good biological compatibility when they were tested by contrast to ISO 10993 standards, some reports have proved that many medical devices loaded with silver could release silver ions (Ag+) which could translocate in blood circulation and cumulate in some organs such as liver and kidney. It may induce hepatotoxicity or renal toxicity and may lead to death in some situation extremely exposed to a certain dose of Ag+. The dimension of silver nanoparticles is close to silver ions and some reports have proved that they could translocate in body, so it is suggested that silver nanoparticles should induce the same toxicity with silver ions. In addition, silver nanoparticles have shown cytotoxicity in some experiment in vitro. But the mechanisms of its cytotoxity are not clear; it may attribute to the silver ions that release from silver nanoparticles or to the silver nanoparticles that permeate through cell membrane. Hence, there are some potential anxieties for the biological safety of silver nanoparticles.

A long term accelerating corrosion fatigue texting of coronary stents in vitro / 生物医学工程学杂志

According to the related standards, an in vitro corrosion fatigue testing of coronary stents was designed. The stents were fixed in the latex tubes, which were full of 0.9% saline solution, and radial stress was produced for simulating natural vessel. The accelerated fatigue test was performed with 4 x 10(8) cycles at a frequency of 60 Hz, which was equal to 10 years in vivo implantation. Twelve coronary stents made from stainless steel were adopted in the experiment. The bulk structure and surface morphology before and after testing were analysed by scanning electron microscopy. The structure damage and surface change caused by corrosion fatigue were identified and the probable reasons were proposed.

The effect of buyanghuanwu decoction on expression of AMPA receptor GluR1 subunit in mRNA and protein levels in rat hippocampus with vascular dementia / 中国病理生理杂志

AIM:To observe the effect of buyanghuanwu decoction,a Chinese medicine,on the expression of AMPA receptor GluR1 subunit in mRNA and protein levels in rat hippocampus with vascular dementia (VD). METH-ODS:One hundred and forty -four rats were randomly divided into 4 groups:shamoperation group,VD model group,nimodipine group and buyanghuanwu decoction treatment group. The rat model of VD was built up by the method of 4 vessel occlusion. The VD rats were intragastrically treated with buyanghuanwu decoction suspension (pharmacognostic 50 g. kg -1.d -1) and nimodipine suspension (20 mg?kg -1.d-1) for 30 d. The learning and memory abilities were evaluated by Morris water maze testing. The change of GluR1 protein in hippocampal neurons in each group of rats was measured with immunohistochemistry and Western blotting techniques. The expression of GluR1 mRNA in hippocampus was determined by real -time fluorescence quantitative PCR. RESULTS:Compared to sham -operation group,the average escaping latency period (s) of Water maze tests in VD rats prolonged significantly and crossplatform time (numbers/min) shortened distinctly (P 0. 05). Compared to the rats in shamoperation group,the mRNA and protein levels of GluR1 were apparent-ly decreased in VD rats (P 0. 05). CONCLUSION:Buyanghuanwu decoction improves the learning and memory abilities in VD rats. The therapeutic mechanism is associated with lessening the neuron injury on CA1 field in hippocampus and restoring the mRNA and protein ex-pression of GluR1.