Chitosan and Derivatives: Bioactivities and Application in Foods.

Chitosan is a biodegradable, biocompatible, and nontoxic aminopolysaccharide. This review summarizes and discusses the structural modifications, including substitution, grafting copolymerization, cross-linking, and hydrolysis, utilized to improve the physicochemical properties and enhance the bioactivity and functionality of chitosan and related materials. This manuscript also reviews the current progress and potential of chitosan and its derivatives in body-weight management and antihyperlipidemic, antihyperglycemic, antihypertensive, antimicrobial antioxidant, anti-inflammatory, and immunostimulatory activities as well as their ability to interact with gut microbiota. In addition, the potential of chitosan and its derivatives as functional ingredients in food systems, such as film and coating materials, and delivery systems is discussed. This manuscript aims to provide up-to-date information to stimulate future discussion and research to promote the value-added utilization of chitosan in improving the safety, quality, nutritional value and health benefits, and sustainability of our food system while reducing the environmental hazards.

Experimental computed tomography-guided vena cava puncture in pigs for percutaneous brachytherapy of middle mediastinal lymph node metastases / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Percutaneous brachytherapy is a valuable method for the treatment of lung cancer and mediastinal lymph nodes metastasis. However, in some of the metastatic lymph nodes in the middle mediastinum, the percutaneous approach cannot be used safely due to possible damage to surrounding anatomical structures. We established an animal model (group of 12 pigs) to assess the safety and feasibility of computed tomography (CT)-guided vena cava puncture.</p><p><b>METHODS</b>Under CT guidance, an 18G needle was used to puncture the anterior wall of the anterior vena cava (AVC) in 12 pigs. The 18G needle was chosen as it is similar in size to the needles employed for clinical application in brachytherapy. The incidence of complications and vital signs was monitored during the procedure. Thoracotomy was performed to remove AVC specimens, which were analyzed for histological evidence of vessel wall damage and repair.</p><p><b>RESULTS</b>Following postoperative enhanced CT, two animals were found to have a small pneumothorax (one being hemopneumothorax). The intraoperative oxygen saturation of both animals was not significantly decreased and was maintained at 93-100%. No animals developed mediastinal hematoma. Preoperative, intraoperative, and postoperative changes in blood pressure, heart rate, hemoglobin, and blood oxygen saturation were not significant. Histological evaluation of AVC specimens showed that by 7 days following the procedure, the endothelial layer was smooth with notable scar repair in the muscularis layer.</p><p><b>CONCLUSIONS</b>CT performed after the procedure and histological preparations confirmed the safety of the procedure. This indicates that percutaneous brachytherapy for metastatic middle mediastinal lymph nodes can be carried out via the superior vena cava.</p>

Acute oral toxicity of 3-MCPD mono- and di-palmitic esters in Swiss mice and their cytotoxicity in NRK-52E rat kidney cells.

The acute oral toxicity of 1-palmitoyl-3-chloropropanediol (3-MCPD 1-monopalmitate) and 1,2-bis-palmitoyl-3-chloropropanediol (3-MCPD dipalmitate) in Swiss mice were examined, along with their cytotoxicity in NRK-52E rat kidney cells. LD50 (median lethal dose) value of 3-MCPD 1-monopalmitate was determined 2676.81 mg/kg body weight (BW). The results showed that 3-MCPD 1-monopalmitate dose-dependently decreased the mean body weight, and caused significant increase of serum urea nitrogen and creatinine in dead mice compared to the control and survived mice. Major histopathological changes in mice fed 3-MCPD 1-monopalmitate were renal tubular necrosis, protein casts and spermatids decrease in the seminiferous tubules. According to the limit test for 3-MCPD dipalmitate, LD50 value of 3-MCPD dipalmitate was presumed to be greater than 5000 mg/kg BW. Obvious changes were not observed on mean body weight, absolute and relative organ weight or serum urea nitrogen and creatinine levels in mice fed 3-MCPD dipalmitate. However, renal tubular necrosis, protein casts and spermatids decrease were also observed in the dead mice. In addition, MTT and LDH assay results only showed the cytotoxicity of 3-MCPD 1-monopalmitate in NRK-52E rat kidney cells in a dose-dependent manner. Together, the results indicated a greater toxicity of 3-MCPD 1-monopalmitate compared to 3-MCPD dipalmitate.

Phenolics content and antioxidant activity of tartary buckwheat from different locations.

Two tartary buckwheat samples (Xingku No.2 and Diqing) grown at three locations were analyzed for free and bound phenolic content and antioxidant properties. Moreover, the relative contributions of variety and growing environment to phenolic content and antioxidant properties were determined, as well as correlations of these properties to growing conditions. The total phenolic contents varied from 5,150 to 9,660 µmol of gallic acid equivalents per 100 gram of dry weight (DW) of tartary buckwheat and the free phenolics accounted for 94% to 99%. Rutin content was in the range from 518.54 to 1,447.87 mg per 100 gram of DW of tartary buckwheat. p-Hydroxybenzoic, ferulic and protocatechuic acids were the prominent phenolic acids and other phenolics, including p-coumaric, gallic, caffeic, vanillic and syringic acids were also detected. Tartary buckwheat exhibited higher DPPH· and ABTS·+ scavenging activities and was more effective at preventing the bleaching of ß-carotene in comparison with reference antioxidant and plant phenolics constituents. Additionally, growing conditions and the interaction between variety and environment may have more contribution than variety to individual phenolics and antioxidant properties of tartary buckwheat. Environmental parameters such as higher altitudes may also have an increasing effect on rutin and phenolic acids. This study suggests that tartary buckwheat has potential health benefits because of its high phenolic content and antioxidant properties. These components could also be enhanced by optimizing the growing conditions of a selected variety.

Isolation and Characterization of a New High Efficient H2-producing Bacterium Enterococcus sp. LG1 / 微生物学通报

12 strains of H2-producing bacteria were isolated and purified from anaerobic sludge, aerobic sludge and river bottom sludge by Hungate method. A new species of high efficient hydrogen production bacterium Enterococcus sp. LG1 (registration number: EU258743 ) was studied deeply. It was showed that the Enterococcus sp. LG1 was an anaerobic and Gram-negative bacterium. Sequence analysis of this type of clones showed that it was affiliated with the genus Enterococcus and it was not reported yet in other paper at present. Meanwhile, batch tests of anaerobic fermentative hydrogen production by Enterococcus sp. LG1 were investigated by using sterilization pretreated sludge as substrate. The changes of soluble COD, protein, carbohydrate and pH value during hydrogen fermentation were monitored. It was found that only hydrogen and carbon dioxide were produced by this strain and no methane was detected during fermentation. The maximal hydrogen yield was 36.48 mL/g TCOD and the hydrogen concentration in the gas phase was 73.5%. The Enterococcus sp. LG1 was a butyrate fermentation bacteria analyzed by metabolites.

Application of endovascular thoracic branched aortic stent-grafts in the treatment of aortic arch dissection / 中华外科杂志

<p><b>OBJECTIVE</b>To report the initial clinical experience of endovascular thoracic branched stent grafts in the treatment of aortic arch dissections involving the left subclavian artery.</p><p><b>METHODS</b>From February 2004 to June 2004, 14 patients were cured with the endovascular thoracic branched aortic stent-grafts made by Beijing YuHengJia SciTech Co. All patients had Stanford type B aortic dissection with the entry tears just beyond the origin of the left subclavian artery by an average distance of 8.7 mm. The branched stents were consisted of the aortic section and the branched section. The diameter of the stents was 15% to 20% larger than the diameter of the landing zones of native arteries. The repair procedure was performed in angiography laboratory. The branched stent grafts were delivered under fluoroscopic guidance and implanted into the aortic arch including the left subclavian artery.</p><p><b>RESULTS</b>Fourteen branched stent-grafts and 2 additional flexible stent-grafts were delivered successfully in all 14 cases. The entry tears were excluded completely, and the truth lumen of the dissection was revealed to the normal diameter in all patients. Neither peripheral complication nor death occurred. All 14 patients had recover the normal life.</p><p><b>CONCLUSION</b>It demonstrates that it is possible to apply the technical feasibility of endovascular thoracic branched aortic stent graft to repair the intimal tear of dissection just beyond the left subclavian artery.</p>

Effect of electroacupuncture on expression of IFN-gamma-like immunoreactive substance in spinal cord of the rat / 中国针灸

<p><b>OBJECTIVE</b>To observe effect of electroacupuncture at "Zusanli" (ST 36) on expression of interferon-gamma (IFN-gamma)-like immunoreactive substance in spinal cord of the rat and to probe the mechanism.</p><p><b>METHODS</b>The IFN-gamma-like immunoreactive positive cell number in spinal cord of the rat was investigated with immunohistochemical SP method and microscopy.</p><p><b>RESULTS</b>After electroacupuncture at "Zusanli" (ST 36), IFN-gamma-like immunoreactive positive cell number in the spinal cord of the rat with electroacupuncture plus immunosuppression did not significantly change (P > 0.05). The number of positive cells in the dorsal horn in the rats with immunosuppression was significantly less than that in the normal control group (P < 0.05) with no significant change in other parts and with no significant difference between the electroacupuncture group and the control group (P > 0.05).</p><p><b>CONCLUSION</b>Electroacupuncture at "Zusanli" (ST 36) can increase expression of IFN-gamma-like immunoreactive substance in spinal cord of the rat, and acupuncture activates the nerve-immunoregulative network possibly by IFN-gamma as medium.</p>