Laser photolysis of carboxymethylated chitin derivatives in aqueous solution. Part 2. Reaction of OH* and SO4*- radicals with carboxymethylated chitin derivatives

The reactions of OH* or SO4*- radicals with carboxymethyl chitin (CM-chitin) and its deacetylated product, carboxymethyl chitosan (CM-chitosan), were investigated in aqueous solutions using a laser photolysis technique. The rate constants of the reactions of OH* and SO4*- radicals with CM-chitosan are always higher than those for CM-chitin, indicating that the amino-group could increase the reactivity of carboxymethylated chitin derivatives. The rate of the reactions of CM-chitin and CM-chitosan with OH* radical was found to decrease at lower pH when polymers chains tend to the coiled conformation. In comparison, the rate constant of the reaction of SO4*- radicals with CM-chitin or CM-chitosan decreased with pH, indicating that CM-chitin or CM-chitosan has a higher reactivity with the SO4*- radical at low pH due to the protonation of the amino group.     

Laser photolysis of carboxymethylated chitin derivatives in aqueous solution. Part 1. Formation of hydrated electron and a long-lived radical

Laser photolysis experiments on carboxymethylated chitin derivatives, such as carboxymethyl chitin (CM-chitin) and carboxymethyl chitosan (CM-chitosan), in aqueous solution by a 248 nm excimer laser were carried out for the first time. The transient absorption spectra of photolyzed CM-chitin or CM-chitosan solutions revealed a strong band with the maximum at 720 nm, which was assigned to the hydrated electron (eaq-). In the presence of argon, the eaq- decays by reacting with CM-chitin or CM-chitosan, and the rate constants are (6.1 +/- 0.1) x 10(7) M(-1) s(-1) and (3.7 +/- 0.1) x 10(7) M(-1) s(-1), respectively. Long-lived radicals with relatively weak absorption intensity were detected in the near-UV region. The absorption band was not notably characteristic and showed only an increasing absorption toward shorter wavelengths. It is similar to the signal of *CM-chitin or *CM-chitosan macroradicals formed by the reaction of CM-chitin or CM-chitosan with an OH* radical. It was assigned to *CM-chitin- or *CM-chitosan- macroradicals formed by eaq- + CM-chitin or CM-chitosan reaction. CM-chitin aqueous solutions were further examined by pulse radiolysis in order to confirm the site of the long-lived radical.     

羧甲基壳聚糖膜对皮肤成纤维细胞相容性研究

通过玻璃流延法制备不同分子质量的壳聚糖及羧甲基壳聚糖膜,以体外培养的人皮肤成纤维细胞作为对象,利用膜的浸渍液培养及膜表面直接培养法研究比较了两种多糖膜的细胞相容性.实验发现两种多糖膜的浸渍液对细胞均无毒性效应,生物安全性是小分子质量膜好于大分子质量膜,羧甲基壳聚糖膜好于壳聚糖膜.皮肤成纤维细胞在壳聚糖膜上的生长受到抑制,生长一段时间后细胞有聚集和脱落现象,而羧甲基壳聚糖膜上细胞能很好地贴附、生长,没有聚集和脱落现象.结果表明羧甲基壳聚糖膜具有比壳聚糖膜更优越的细胞相容性.     

灯盏花素辅助治疗对急性脑梗死患者的疗效分析

目的:观察灯盏花素辅助治疗对急性脑梗死患者血液流变学、血管内皮功能及凝血功能的影响。方法:选择本院确诊为急性脑梗死的患者共144例,包括观察组和对照组各72例,对照组采用常规对症治疗,观察组在对照组基础上加用灯盏花素静脉滴注辅助治疗,比较两组患者治疗前后血液流变学、血管内皮功能及凝血功能的差异。结果:经治疗后,观察组NIHSS评分(3.01±1.40)显著低于对照组(3.96±2.17),观察组总有效率显著高于对照组(94.4%vs.86.1%,P0.05)。两组间治疗前各指标水平差异未发现统计学意义(P0.05);两组治疗后全血黏度(whole blood viscosity,WBV)、全血还原黏度(whole blood reduced viscosity,WBRV)、血浆粘度(plasma viscosity,PV)和红细胞聚集指数(erythrocyte aggregation index,EAI)均显著降低(P0.05);其中观察组各个指标均显著低于对照组(P0.05);两组治疗后血管内皮素-1(endothelin-1,ET-1)水平与循环内皮细胞(circulating endothelial cell,CEC)计数显著降低,而一氧化氮(nitrie oxide,NO)及可溶性血栓调节蛋白(soluble thrombomodulin,s TM)水平显著升高(P0.05),其中观察组ET-1水平显著低于对照组,而NO及sTM水平显著高于对照组(P0.05);两组治疗后凝血酶原时间(prothrombin time,PT)及部分活化凝血酶原时间(activated partial thromboplastion time,APTT)显著升高,纤维蛋白原(fibrinogen,Fib)和D-二聚体(D-dimer,DD)显著降低(P0.05);其中观察组PT和APTT显著高于对照组,DD显著低于对照组(P0.05)。结论:灯盏花素辅助治疗能有效改善急性脑梗死患者血液粘稠状态,保护血管内皮功能及改善凝血功能。     

舒芬太尼自控静脉镇痛对肺癌切除术后患者血流动力学及免疫功能的影响

目的:探讨舒芬太尼自控静脉镇痛对肺癌切除术后患者血流动力学及免疫功能的影响。方法:选择2009年2月-2014年2月在我院行肺叶切除术的非小细胞肺癌(NSCLC)患者110例,依据随机数字表法将全部患者分为对照组和观察组,每组55例。术后观察组患者接受舒芬太尼自控静脉镇痛,对照组接受芬太尼自控静脉镇痛,观察两组患者血液动力学指标和免疫功能指标的差异。结果:镇痛1 d后,观察组全血粘度、全血还原粘度、红细胞聚集指数(RAI)和毛细血管血浆粘度均显著低于对照组(均P0.05),CD4+T细胞、IL-2含量观察组显著高于对照组(P0.05),CD8+T细胞、IL-6、IL-10含量观察组均显著低于对照组(均P0.05)。结论:肺癌根治术后采用舒芬太尼自控静脉镇痛可显著调节患者血流动力学指标,改善机体免疫功能,可推广临床实践。     

Effect of chitin sources on production of chitinase and chitosanase byStreptomyces griseus HUT 6037

The advantage of usingStreptomyces griseus HUT 6037 in the production of chitinase or chitosanase is that the organism is capable of hydrolyzing amorphous or crystal-line chitin and chitosan according to the type of the substrate used. We investigated the effects of the enzyme induction time and chitin sources, CM-chitosan and deacetylated chitosan (degree of deacetylation 75–99%), on production of chitosanase. We found that this strain accumulated chitosanase when cells were grown in the culture medium containing chitosanaceous substrates instead of chitinaceous substrates. The highest chitosanase activity was obtained at 4 days of cultivation with 99% deacetylated chitosan. Soluble chitosan (53% deacetylated chitosan) was found to induce chitinase as well as chitosanase. The specific activities of chitinase and chitosanase were 0.91 and 1.33 U/mg protein at 3 and 5 days, respectively. From the study of the enzymatic digestibility of various degrees of deacetylated chitosan, it was found that (GlcN)₃, (GlcN)₄ and (GlcN)₅ were produced during the enzymatic hydrolysis reaction. The results of this study suggested that the sugar composition of (GlcN)₃ was homogeneous and those of (GlcN)₄ and (GlcN)₅ were heterogeneous.     

Effect of dietary chitosans with different viscosity on plasma lipids and lipid peroxidation in rats fed on a diet enriched with cholesterol

To investigate the effect of dietary chitosan on lipid metabolism, male SD (Sprague-Dawley) rats were fed a cholesterol-enriched diet containing 5% cellulose (CE), 5% chitosan (CCS; high viscosity), or 5% chitosan (FCS; low viscosity) for 4 weeks. The two types of chitosan with a comparable degree of deacetylation had a different molecular weight and intrinsic viscosity. Significantly (p < 0.05) lower plasma total cholesterol, LDL-cholesterol and VLDL-cholesterol concentrations were observed in the rats fed on the chitosan diets. In addition, chitosan significantly increased the fecal cholesterol and triglyceride contents. Although no significant difference in body weight was found among the dietary groups, the rats fed on the chitosan diets had lower relative liver weight when compared with those fed on the cellulose diet. Both of the chitosan groups had significantly lower liver total lipid and total cholesterol contents compared to the cellulose group, although the FCS group was less effective. The plasma and liver thiobarbituric acid reactive substances (TBAR) values were similar in the CE and FCS groups, while the CCS group had increased liver TBAR values. Although a significant increase in liver glucose-6-phosphate dehydrogenase activity was observed in the CCS group, no significant change was found in the FCS group. The observed influence of chitosans with different viscosity on the plasma lipid level, liver lipids and lipid peroxidation suggests that, while the hypocholesterolemic action of chitosans with different viscosity was similar, changes in the liver lipids and liver peroxidation status depended on their molecular weight when the deacetylation degree was comparable.     

Synthesis of antibacterial PVA/CM-chitosan blend hydrogels with electron beam irradiation

A series of excellent hydrogels were prepared from poly(vinyl alcohol) (PVA) and carboxymethylated chitosan (CM-chitosan) with electron beam irradiation (EB) at room temperature. Electron spectroscopy analysis of the blend hydrogels revealed that good miscibility was sustained between CM-chitosan and PVA. The properties of the prepared hydrogels, such as the mechanical properties, gel fraction and swelling behavior were investigated. The mechanical properties and equilibrium degree of swelling improved obviously after adding CM-chitosan into PVA hydrogels. The gel fraction determined gravimetrically showed that a part of CM-chitosan was immobilized onto PVA hydrogel. The further analyses of FTIR and DSC spectra of the prepared gels after extracting sol manifested that there was a grafting interaction between PVA and CM-chitosan molecules under irradiation. The antibacterial activity of the hydrogels against Escherichia coli was also measured via optical density method. The blend hydrogels exhibited satisfying antibacterial activity against E. coli, even when the CM-chitosan concentration was only 3 wt%.     

Preparation of cross-linked carboxymethyl chitosan for repairing sciatic nerve injury in rats

A successful nerve regeneration process was achieved with nerve repair tubes made up of 1-ethyl-3(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) cross-linked carboxymethyl chitosan (CM-chitosan) with improved biodegradability. Chitosan has a very slow degradation rate, while the EDC cross-linked CM-chitosan tubes degraded to 30% of original weight during 8 weeks of incubation in lysozyme solution. In vitro cell culture indicated that the CM-chitosan films presented no cytotoxicity to Schwann cells. From in vivo studies using a 10 mm rat sciatic nerve defect model investigated by histomorphometry analysis, the average diameter of the fibers and the average thickness of myelin sheath in the CM-chitosan tubes were 3.7 ± 0.33 and 0.33 ± 0.04 μm, respectively, which demonstrated equivalence to nerve autografts (the current “gold” standard); furthermore, the average fiber density in the CM-chitosan tubes was 20.5 × 10³/mm², which was similar to that of autografts (21 × 10³/mm²) and significantly higher than that of common chitosan tubes (15.3 × 10³/mm²).     

脑心通胶囊联合阿替普酶治疗急性脑梗死的疗效及对凝血功能、血液流变学和认知功能的影响

摘要 目的：探究脑心通胶囊联合阿替普酶治疗急性脑梗死（ACI）的疗效,并观察该治疗方案对凝血功能、血液流变学和认知功能的影响。方法：选取我院于2016年6月~2020年12月期间收治的137例ACI患者。按照随机数字表法将患者分为对照组和观察组,其中对照组68例,接受阿替普酶治疗,观察组69例,接受脑心通胶囊联合阿替普酶治疗,两组均治疗10 d。比较两组治疗10 d后的临床总有效率,观察两组治疗前、治疗10d后的凝血功能、血液流变学和认知功能变化情况,记录两组肝肾功能、血常规异常情况及药物不良反应。结果：两组临床总有效率组间对比有明显差异（P＜0.05）。与治疗前比较,两组患者治疗10 d后活化部分凝血活酶时间（APTT）、凝血酶原时间（PT）、凝血酶时间（TT）均延长,D-二聚体（D-D）、全血低切黏度、全血高切黏度、血浆黏度、红细胞比容均降低（P＜0.05）,且与对照组相比,观察组以上指标改善均更为显著（P＜0.05）。与治疗前比较,治疗10 d后两组患者美国国立卫生研究院卒中量表（NIHSS）评分均降低,日常生活能力量表（ADL）评分均升高（P＜0.05）,且与对照组相比,观察组以上评分改善均更为显著（P＜0.05）。两组用药期间血常规、肝肾功能均无异常情况,未见严重不良反应发生。与治疗前比较,两组患者治疗10d后老年快速认知筛查量表（QCST-E）各维度评分均升高（P＜0.05）,且与对照组相比,观察组改善更为显著（P＜0.05）。结论：在阿替普酶治疗基础上联合脑心通胶囊治疗ACI,可改善患者神经功能,提高患者日常生活能力,并促进凝血功能、血液流变学和认知功能改善。     

Synthesis of room temperature ionic liquids from carboxymethylated chitosan

Natural oligosaccharide-derived room temperature ionic liquids (RTILs) were prepared from 1-ethyl-3-methylimidazolium hydroxide (EMIM·OH) and carboxymethylated chitosan (CM-chitosan) by acid–base neutralization reaction. These EMIM·CM-chitosan ionic liquids exhibited good ionic conductivity and thermal stability, as well as low glass transition temperature, implying their potential wide applications in direct electrochemistry, biosensors, and biocatalysis.     

Applying the Taguchi Design for Optimized Formulation of Sustained Release Gliclazide Chitosan Beads: An In Vitro/In Vivo Study

Gliclazide is a second generation of hypoglycemic sulfonylurea and acts selectively on pancreatic β cell to control diabetes mellitus. The objective of this study was to produce a controlled release system of gliclazide using chitosan beads. Chitosan beads were produced by dispersion technique using tripolyphosphate (TPP) as gelating agent. The effects of process variables including chitosan molecular weight, concentration of chitosan and TPP, pH of TPP, and cross-linking time after addition of chitosan were evaluated by Taguchi design on the rate of drug release, mean release time (MRT), release efficiency (RE₈%), and particle size of the beads. The blood glucose lowering effect of the beads was studied in normal and streptozotocin-diabetic rats. The optimized formulation CL₂T₅P₂t₁₀ with about 31% drug loading, 2.4 h MRT, and 69.16% RE₈% decreased blood glucose level in normal rats for 24 h compared to pure powder of gliclazide that lasted for just 10 h.     

Thiolation of chitosan. Attachment of proteins via thioether formation

Chitosan has a variety of biological functions through conjugating of other compounds to their amino and hydroxyl groups. To further expand applicability of chitosan, we have modified the amino group of chitosan with 2-iminothiolane to bestow thiol groups and obtained about 20% yield, which is equivalent to 913 microequiv SH/g chitosan or 457 nequiv SH/nmol chitosan. Bovine serum albumin (BSA) was reacted with N-(epsilon-maleimidocaproyloxy)sulfosuccinimide ester (sulfo-EMCS), and maleimide-modified BSA (MalN-BSA) was obtained. The yield of sulfo-EMCS addition was 12.8-36.8 mol MalN/mol BSA. When the chitosan-SH was reacted with MalN-BSA via thioether, 97.8% of the maleimide group was reacted, and 37.2% of the SH group was consumed. The remaining SH group was quenched by bromoacetamide. This is the first report of covalent conjugation of a protein to chitosan. Our method should find many applications in developing new chitosan-based biomedical materials containing other components such as growth factors and cell adhesion molecules, known to be crucial to cells. Our thiolated chitosan will facilitate conjugation of such biomedical components to provide new types of materials for tissue engineering.     

Effects of Scrambling trumpet Creeper flavone on transient cerebral ischemia model (TIA) in rats

To investigate the effects of Scrambling Trumpet Creeper flavone on neurological function score, brain tissue lesion and related biochemical indexes in rat TIA model. Methods: TIA model was induced by tail vein injection of t-butanol (t-BHP). The rats in each administration group were given large, medium and low dose of Scrambling Trumpet Creeper flavone 0.1% CMC suspension, nimodipine and Yangxueqingnao particles group 0.1% CMC suspension, model group and blank group fed the same volume 0.1% CMC. Once a day, continuous administration of 7d. On the 3rd and 6th day after administration, t-BHP was injected into the tail vein, and then placed in a sealed 1?L?jar. After 10?min of hypoxia, the neurological function score (NDS) was performed. After the first 2 days of TIA administration, the hem rheology was measured immediately after 1?h of administration, and blood rheology was measured immediately after the administration of blood, blood clotting, hematocrit, hematocrit and whole blood viscosity. After HE is staining to observe the pathological changes of hippocampus and cortex in the left-brain tissue. (LDH) and adenosine triphosphate (ATP) were measured. The right brain tissue of the cerebral cortex was observed. The expression of lactate (LD), lactate dehydrogenase (LDH) Fibroblast growth factor (FGF) and insulin growth factor (IGF) were detected by immunohistochemistry.

Effects of a chitosan intake on the fecal excretion of dioxins and fat in rats

We evaluated the effects of the intake of various dietary fibers on the fecal excretion of dioxins in rats. The rats were fed five types of dietary fiber diets, including a chitosan diet and control diet, for 20 d and then dioxins (120 ng/rat) were orally administered on day 15. The excretion of fecal dioxins was significantly higher in the chitosan group than in the control group, and dioxin excretion was positively correlated with fecal fat excretion. A comparison of the different types of chitosan showed that the efficacy of chitosan for fecal fat excretion was partly related to its viscosity. The chitosan intake promoted fecal dioxin excretion when the rats were exposed to highly toxic dioxins, and this excretion of fecal dioxins was related to the fecal fat excretion, suggesting that chitosan might be useful for reducing the adverse effects caused by lipophilic xenobiotics.     

Preparation and properties of alginate/carboxymethyl chitosan blend fibers

Alginate/carboxymethyl chitosan blend fibers, prepared by spinning their mixture solution through a viscose-type spinneret into a coagulating bath containing aqueous CaCl₂, were studied for structure and properties with the aid of infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron micrography (SEM). The analyses indicated a good miscibility between alginate and carboxymethyl chitosan, because of the strong interaction from the intermolecular hydrogen bonds. The best values of the dry tensile strength and breaking elongation were obtained when carboxymethyl chitosan content was 30 and 10 wt%, respectively. The wet tensile strength and breaking elongation decreased with the increase of carboxymethyl chitosan content. Introduction of CM-chitosan in the blend fiber improved water-retention properties of blend fiber compared to pure alginate fiber. Antibacterial fibers, obtained by treating the fibres with aqueous solution of N-(2-hydroxy)-propyl-3-trimethylammonium chitosan chloride and silver nitrate, respectively, exhibited good antibacterial activity to Staphylococcus aureus.     

Sulfated chitin and chitosan as novel biomaterials

Chitin and chitosan are known to be natural polymers and they are non-toxic, biodegradable and biocompatible. Chemical modification of chitin and chitosan with sulfate to generate new bifunctional materials is of interest because the modification would not change the fundamental skeleton of chitin and chitosan, would keep the original physicochemical and biochemical properties and finally would bring new or improved properties. The sulfated chitin and chitosan have a variety of applications, such as, adsorbing metal ions, drug delivery systems, blood compatibility, and antibacterial field. The purpose of this review is to take a closer look about the different synthetic methods and potential applications of sulfated chitin and chitosan. Based on current research and existing products, some new and futuristic approaches in this context area are discussed in detail. From the studies reviewed, we concluded that sulfated chitin and chitosan are promising materials for biomedical applications.     

D- 二聚体、血流变学指标对结缔组织病患者诊疗价值研究

目的:探讨分析结缔组织病合并多器官损害患者D-二聚体(DD)、血流变学指标(血浆纤维蛋白原/血浆纤维蛋白降解产物FDP、全血黏度、血浆黏度)水平及指标变化对结缔组织病合并多器官损害患者病情活动期的诊疗价值。方法:本研究共纳入120例患者,其中活动组患者60例,病情缓解组患者60例,分别测定二组患者DD、血流变学指标水平,并采用t检验、灵敏度与特异度进行统计学分析与描述。结果:与缓解组比较,活动组DD、纤维蛋白降解产物(FDP)、全血黏度、血浆黏度、γ球蛋白、补体C4、ESR均具有统计学差异(P0.01),补体C3组间差异也具有统计学意义(P0.05)。各指标对于疾病活动性诊断的准确性,其DDFDP补体C3、C4γ-球蛋白血浆黏度全血黏度ESR。结论:结缔组织病合并多器官损害患者,其纤溶水平、微循环状态与疾病活动密切相关。