米糠甾醇对非酒精性脂肪性肝炎大鼠的治疗作用

目的：研究米糠植物甾醇对非酒精性脂肪性肝炎（non-alcoholic steatohepatitis,NASH）大鼠的干预治疗作用。方法：实验选用50只健康SD雄性大鼠,随机分为正常对照组、NASH模型组和米糠甾醇低、中、高3个剂量组（65、130、195 mg/kg）。高脂饲料饲喂造模,各实验组同时进行米糠甾醇溶液灌胃干预。13周后观察各组大鼠肝组织病理学特点,测定血清中血脂总胆固醇、甘油三酯、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇含量和谷丙转氨酶、谷草转氨酶、一氧化氮合酶和超氧化物歧化酶活性,并比较各组肝脏指数和脾脏指数。结果：肝脏组织切片观察到NASH模型组有明显的肝细胞脂肪变性和炎症聚集浸润,米糠甾醇各治疗组肝组织病变呈现不同程度减轻。NASH模型组血清高密度脂蛋白胆固醇含量、超氧化物歧化酶、一氧化氮合酶、谷丙转氨酶和谷草转氨酶活性与正常对照组相比,均表现出明显异常;米糠甾醇各剂量组与NASH模型组比较,血清谷丙转氨酶显著降低（P＜0.001）、谷草转氨酶/谷丙转氨酶比值显著升高（P＜0.01）;低剂量组血清超氧化物歧化酶（P＜0.05）和一氧化氮合酶（P＜0.001）显著降低;中剂量组血清高密度脂蛋白胆固醇显著升高（P＜0.05）。结论：米糠甾醇对大鼠非酒精性脂肪性肝炎有预防与治疗作用。     

牛血清蛋白在亲水硅片表面吸附的原子力显微成像

本文用原子力显微术（AFM）研究了牛血清白蛋白（BSA）在亲水硅片表面的吸附，硅片表面经亲水处理后，将牛血清蛋白（BSA）吸附在表面，采用轻敲模式，可获得清晰的AFM图像，牛血清蛋白（BSA）的AFM图像表明：BSA在亲水硅片表面是单分子，水平吸附在硅片表面，且吸颗粒状；1mg/ml的BSA在吸附30min后为饱和吸附。BSA到达硅表面后，蛋白中可移动的带正电荷的基团可以趋向亲水表面，使BSA与硅表面的静电相互作用由斥力变为吸引力，BSA可以稳定地吸附在亲水硅片表面。     

金银花及其制剂含药血清中绿原酸HPLC紫外光谱测定和抑菌活性研究

目的:考察金银花及其复方制剂的含药血清抑菌效果.方法:采用最低抑菌浓度(MIC)测定方法和抑菌活性试验方法.结果:金银花含药血清和银黄口服液含药血清对大肠杆菌的MIC都为1μg/mL;对金黄色葡萄球菌的MIC分别为0.5μg/mL和0.25μg/mL,含药血清抑菌活性为高敏.结论:金银花及其复方制剂的含药血清具有较强的抑菌作用.     

Effects of harvest time on the quality attributes of processed and non‐processed tomato varieties

This study examines physicochemical changes in newly developed and existing tomato varieties at different levels of maturity. Serum viscosity is an important factor in the selection of tomato varieties for processing. Most of the attributes indicative of quality for fresh and paste tomatoes occurred at a less mature stage and declined with maturity. The canned varieties ‘H9888,’‘H8892’ and ‘H9780’ had a greater ascorbic acid content and antioxidant capacity. The highest lycopene contents were found in the varieties ‘H9888,’‘CXD254,’‘CXD222’ and ‘H9780’. Total soluble solids levels increased with maturity. The highest acidity values occurred in canned ‘Shasta’, ‘CXD254’ and ‘H9780’ varieties. Mid‐ and late‐season varieties harvested at an early stage produced thicker pastes with greater serum viscosity and acidity than tomatoes harvested at other points in the ripening process. The best results were obtained from canned samples of ‘H9888,’‘CXD254’ and ‘H9780.’     

Copper Transfer from Cu–Aβ to Human Serum Albumin Inhibits Aggregation,Radical Production and Reduces Aβ Toxicity

Amyloid‐β peptides (Aβ) and the protein human serum albumin (HSA) interact in vivo. They are both localised in the blood plasma and in the cerebrospinal fluid. Among other functions, HSA is involved in the transport of the essential metal copper. Complexes between Aβ and copper ions have been proposed to be an aberrant interaction implicated in the development of Alzheimer's disease, where Cu is involved in Aβ aggregation and production of reactive oxygen species (ROS). In the present work, we studied copper‐exchange reaction between Aβ and HSA or the tetrapeptide DAHK (N‐terminal Cu‐binding domain of HSA) and the consequence of this exchange on Aβ‐induced ROS production and cell toxicity. The following results were obtained: 1) HSA and DAHK removed Cu^II from Aβ rapidly and stoichiometrically, 2) HSA and DAHK were able to decrease Cu‐induced aggregation of Aβ, 3) HSA and DAHK suppressed the catalytic HO^. production in vitro and ROS production in neuroblastoma cells generated by Cu–Aβ and ascorbate, 4) HSA and DAHK were able to rescue these cells from the toxicity of Cu–Aβ with ascorbate, 5) DAHK was more potent in ROS suppression and restoration of neuroblastoma cell viability than HSA, in correlation with an easier reduction of Cu^II–HSA than Cu–DAHK by ascorbate, in vitro. Our data suggest that HSA is able to decrease aberrant Cu^II–Aβ interaction. The repercussion of the competition between HSA and Aβ to bind Cu in the blood and brain and its relation to Alzheimer's disease are discussed.     

Combined cross-linking treatments of bovine serum albumin gel beadlets for controlled-delivery of caffeine

Combined cross-linking agents (CCLA) of microbial transglutaminase (MTgase) and ribose were applied during production of bovine serum albumin gels via incubation and heating treatment, respectively. CCLA produced stronger gels with lower protein solubility in disruptive solvents (1% sodium dodecyl sulphate plus 1% β-mercaptoethanol) as compared to BSA gels (BSA/Control) or gels produced using single cross-linking agents (SCLA) of MTGase or ribose. The gels were then converted into dried beadlets containing caffeine following a freeze-drying process. In-vitro controlled-release of caffeine and swelling ratio studies of the beadlets in artificial saliva or simulated gastric fluid indicated that CCLA beadlets had the slowest release of caffeine and the lowest swelling ratio as compared to other beadlets. Scanning electron microscopy (SEM) data suggested that the improved release and the lower swelling ratio were mainly due to the denser network formed within the CCLA beadlets that had restricted the diffusion of caffeine and hampered the enzymatic breakdown of the matrix. The additional protein cross-linkings formed as a result of MTgase incubation and ribose-induced Maillard reaction could provide a delay action in releasing caffeine that potentially extend the duration of the action of the drug during ingestion.     

Desorption of Human Serum Albumin and Human Fibrinogen from the Poly(3-Hydroxybutyrate) Surface

Abstract

The protein desorption of human serum albumin and human fibrinogen from the surface of poly(3-hydroxybutyrate) films was studied with ATR-FTIR spectroscopy. The diffusion model for reversible and irreversible sandwiched layers was confirmed. The reversible ratio (ratio of reversible adsorbed concentration to irreversible one) registrated as a function of time allow us to propose the kinetic model of the initial stage of thromb formation. The parameters of adsorption/desorption for both proteins are compared. The reversible ratio of plasma protein adsorption is proposed as a quantitative criterion of thromb-resistance behavior for polymer in biomedicine, namely, controlled drug release vehicles, artificial vessels, magistrals, reservoirs for blood storage, and surgical threads especially. The mechanism of interaction of protein molecules with PHB macro-molecules is discussed.     

Prevalence and risk factors for bruises in Chilean bovine carcasses

Records of cattle slaughtered at two Chilean slaughterhouses (SLH1 and SLH2) were used to determine prevalence and risk factors for carcasses with bruises. Bruise prevalence amounted to 12.3% but differed between slaughterhouses (20.8% for SLH1 and 8.6% for SLH2 respectively). Bruise severity grade 1 (mild) was most frequently recorded. The type of the animal, source of animal, the level of fat cover and lairage time were associated with the presence of bruises. Older categories of animals and animals that pass through a market before being moved to the slaughterhouse are more prone to show bruises. The results also indicate that under the reported Chilean circumstances animals that have longer lairage times (over 12 h) have a significantly reduced risk for bruises, except for oxen. Presence of bruises is also significantly associated with increased carcass pH values.     

Interaction of Water-Soluble CdTe Quantum Dots with Bovine Serum Albumin

Semiconductor nanoparticles (quantum dots) are promising fluorescent markers, but it is very little known about interaction of quantum dots with biological molecules. In this study, interaction of CdTe quantum dots coated with thioglycolic acid (TGA) with bovine serum albumin was investigated. Steady state spectroscopy, atomic force microscopy, electron microscopy and dynamic light scattering methods were used. It was explored how bovine serum albumin affects stability and spectral properties of quantum dots in aqueous media. CdTe–TGA quantum dots in aqueous solution appeared to be not stable and precipitated. Interaction with bovine serum albumin significantly enhanced stability and photoluminescence quantum yield of quantum dots and prevented quantum dots from aggregating.