九里香叶色素的提取及其稳定性研究

研究九里香叶色素的提取条件和稳定性。以水作提取剂,在室温下浸提24 h,用紫外分析法研究色素的稳定性。色素在330 nm有最大吸收峰,该色素水溶性较好,pH值在1≤pH≤11对此色素的稳定性影响不是很大,但热稳定性良好。淀粉对九里香叶色素影响较大,苯甲酸钠、柠檬酸、醋酸、蔗糖、葡萄糖、维生素C对九里香叶色素稳定性无明显影响,耐光性较差。氧化剂、还原剂对色素的影响明显,其它均无明显影响,金属离子对其影响较小。     

Elucidating the phenomenon of HESC-derived RPE: anatomy of cell genesis, expansion and retinal transplantation

Healthy Retinal Pigment Epithelium (RPE) cells are required for proper visual function and the phenomenon of RPE derivation from Human Embryonic Stem Cells (HESC) holds great potential for the treatment of retinal diseases. However, little is known about formation, expansion and expression profile of RPE-like cells derived from HESC (HESC-RPE). By studying the genesis of pigmented foci we identified OTX1/2-positive cell types as potential HESC-RPE precursors. When pigmented foci were excised from culture, HESC-RPE expanded to form extensive monolayers, with pigmented cells at the leading edge assuming a precursor role: de-pigmenting, proliferating, expressing keratin 8 and subsequently re-differentiating. As they expanded and differentiated in vitro, HESC-RPE expressed markers of both developing and mature RPE cells which included OTX1/2, Pax6, PMEL17 and at low levels, RPE65. In vitro, without signals from a developing retinal environment, HESC-RPE could produce regular, polarised monolayers with developmentally important apical and basal features. Following transplantation of HESC-RPE into the degenerating retinal environment of Royal College of Surgeons (RCS) dystrophic rats, the cells survived in the subretinal space, where they maintained low levels of RPE65 expression and remained out of the cell cycle. The HESC-RPE cells responded to the in vivo environment by downregulating Pax6, while maintaining expression of other markers. The presence of rhodopsin-positive material within grafted HESC-RPE indicates that in the future, homogenous transplants of this cell type may be capable of supporting visual function following retinal dystrophy.     

Steatocholecystitis: the influence of obesity and dietary carbohydrates

INTRODUCTION: We have recently demonstrated that obese and lean mice fed a high fat diet have increased gallbladder wall fat and decreased gallbladder contractility, cholecystosteatosis. Animal and human data also suggest that diets high in refined carbohydrates lead to gallstone formation. However, no data are available on the role of dietary carbohydrates on gallbladder wall fat and inflammation. Therefore, we tested the hypothesis that both obesity and dietary carbohydrates would increase gallbladder fat and cytokines, steatocholecystitis. METHODS: At 8 wk of age, 47 lean and 22 obese female mice were fed a 45% carbohydrate (CHO) diet while an equal number of lean and obese mice were fed a 75% CHO diet for 4 wk. All mice underwent cholecystectomy, and the gallbladders were snap-frozen. Individual and total lipids were measured by gas chromatography. Interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, and IL-6 were measured by enzyme-linked immunosorbent assay. Data were analyzed by analysis of variance and Tukey test. RESULTS: Gallbladder total fat, triglycerides, and cholesterol were maximum (P < 0.001) in obese mice on the 75% CHO diet. Gallbladder TNF-alpha and IL-1beta as well as serum cholesterol levels showed a similar pattern (P < 0.001). Gallbladder saturated free fatty acids and IL-6 levels were highest (P < 0.001) in obese mice on the 45% CHO diet. CONCLUSIONS: These data suggest that (1) both obesity and dietary carbohydrates increase gallbladder total fat, triglycerides, cholesterol, TNF-alpha, and IL-1beta and (2) obesity also increases gallbladder free fatty acids and IL-6. Therefore, we conclude that obesity is associated with steatocholecystitis and that a high carbohydrate diet exacerbates this phenomenon.     

非梯度高效液相色谱法测定四种食用色素的初步探讨

目前所使用的食用色素大都是有机合成色素,研究表明其对人体有一定的毒性。在食品工艺上对食用色素要求较为严格。色素的分析方法很多,目前较为先进的方法是 HPLC 法,但均采用梯度洗脱方式。梯度洗脱时间长,梯度改变时易产生气泡,给分析工作者带来很多不便。本文采用非梯度洗脱,快速、灵敏,可在12min内完成四种混合色素的分离,同时可分离糖精钠和苯甲酸,是一种较好的色素分析方法。     

视网膜酸化诱导VEGF与PEDF表达及其与氧化应激的关系

背景 缺氧与高糖是引起视网膜新生血管生长的主要原因,可引起视网膜糖酵解作用增强,导致组织酸中毒. 目的 探讨视网膜酸中毒对视网膜血管内皮生长因子(VEGF)与色素上皮衍生因子(PEDF)表达的影响及氧化应激的作用.方法 从2周龄雄性SD大鼠中分离出视网膜.分别在NaHCO3调制的pH7.2、6.8、6.5酸性环境的DMEM培养液中培养24 h;另外,在上述酸性培养液中培养后用PBS洗涤视网膜2遍后置于pH值为7.2的新鲜培养液中继续培养24 h;同时,在上述酸性培养液中加入抗氧化剂对视网膜进行培养.制作视网膜标本,然后行苏木精-伊红染色,采用荧光定量聚合酶链反应( PCR)及免疫蛋白印迹技术检测各组大鼠视网膜中VEGF和PEDF蛋白及其mRNA的表达,以pH7.2作为对照. 结果 视网膜培养24 h后,pH7.2组、pH6.8组视网膜层次清晰,但pH6.5组视网膜出现空泡.正常视网膜VEGF mRNA的表达为(112±11)％,pH7.2组为(100±7)％,差异无统计学意义(P=0.55);pH 6.8组、pH 6.5组中的视网膜VEGF mRNA分别为(196±43)％、(251±29)％,均较pH7.2组明显升高,差异均有统计学意义(P＜0.05).正常视网膜PEDF mRNA水平为(86±19)％,pH7.2组为(100±.33)％,差异无统计学意义(P=0.64);pH 6.5组视网膜PEDF mRNA水平为(230±66)％,较pH7.2组明显升高(P＜0.05).VEGF与PEDF蛋白与其mRNA表达趋势一致.视网膜酸化纠正后,pH 7.2、6.8、6.5组视网膜VEGF mRNA分别为(100±13)％、(111±9)％、(113±9)％,3个组之间比较差异无统计学意义(F=2.51,P=0.16).PEDF mRNA的表达分别为(100±13)％、(110±9)％、(108±11)％,3个组之间比较差异无统计学意义(F=0.98,P=0.43).加入抗氧化剂后,pH7.2组视网膜VEGF mRNA水平为(100±9)％,pH6.8组为(106±7)％,pH 6.5组为(148±22)％,pH6.5组VEGF mRNA表达水平均明显高于pH 7.2组和pH 6.8组(P＜0.05).pH 7.2、6.8、6.5组大鼠视网膜PEDF mRNA表达分别为(100±31)％、(282±45)％、(480±117)％,差异有统计学意义(F=20.73,P=0.00).结论 视网膜酸化诱导VEGF的表达受到氧化应激的调节,抗氧化剂可促进酸化视网膜PEDF的表达增加,表明氧化应激可抑制PEDF表达.     

CAN SINCALIDE CHOLESCINTIGRAPHY FULFIL THE ROLE OF A GALL-BLADDER STRESS TEST FOR PATIENTS WITH GALL-BLADDER STONES?

Background: Patients referred to general surgeons for the treatment of gall-bladder stones were studied to evaluate the role of sincalide cholescintigraphy as a gall-bladder stress test in an effort to identify a group of patients whose pain was non-biliary in origin and who would not be improved by cholecystectomy. Methods: Ten asymptomatic controls and 57 patients with gallstones and abdominal symptoms were studied. All patients were interviewed by an independent assessor who identified a group of patients in whom the role of gallstones in their presentation was uncertain (clinically possibly biliary group). All patients and controls underwent sincalide cholescintigraphy. The surgeons remained blinded to the study results throughout the study period. All patients were re-evaluated 6–12 months later to establish the ultimate diagnosis based on their therapeutic response. Results: Several parameters of gall-bladder function were studied from analysis of the sincalide cholescintigram. Lag time, ejection period, ejection rate and ejection fraction did not differ significantly among controls, patients proven to have non-biliary disease and patients proven to have biliary disease. There were significant differences in mean gall-bladder filling fraction between proven biliary and proven non-biliary groups. However, the group of patients with clinically possibly biliary symptoms could not accurately be separated into those who benefited from cholecystectomy and those who improved without surgery on the basis of this parameter. Conclusions: Significant differences in gall-bladder filling fraction between symptomatic and asymptomatic gallstone patients were identified suggesting reduced gall-bladder compliance in symptomatic patients. However, the sincalide cholescintigram failed to emerge as a useful gall-bladder stress test. Even in the 1990s, assessment by an experienced surgeon appears to be the most appropriate way to select patients for cholecystectomy.     

Lipid peroxidation and mucin secretagogue activity in bile of gallstone patients

Background Chronic inflammation of the gallbladder wall and mucin hypersecretion are considered to be important factors in the pathogenesis of cholesterol gallstone disease. The aim of the study was to compare mucin concentration and mucin secretagogue activity with lipid peroxidation in gallbladder bile of patients with cholesterol or pigment stones. Material and methods We studied mucin concentration and, as a marker of lipid peroxidation, malondialdehyde concentration in 11 rapid (1 to 3 days) and eight non‐nucleating (> 21 days) gallbladder biles of patients with cholesterol or pigment stones. Furthermore, the mucin secretagogue activity of rapid and non‐nucleating gallbladder biles, as well as 1–5 µmol L⁻¹ malondialdehyde on cultured gallbladder epithelial cells, was determined. Results Our data show an increased malondialdehyde (7·2 ± 1·8 vs. 3·8 ± 0·5 µmol L⁻¹, P = 0·01) and mucin concentration (0·9 ± 0·09 vs. 0·41 ± 0·03 mg mL⁻¹, P = 0·01) and an increased mucin secretagogue activity (2·0 ± 0·5 vs. 1·1 ± 0·3 mucin secretion/control, P = 0·04) and cholesterol saturation index (1·2 ± 0·1 vs. 08 ± 0·1, P = 0·04) in rapid as compared to non‐nucleating gallbladder biles. Malondialdehyde stimulated mucin secretion of cultured gallbladder epithelial cells in a concentration dependent manner. Conclusions Our results support a promoting effect of gallbladder mucin hypersecretion by lipid peroxidation leading to rapid formation of cholesterol crystals in gallbladder bile. These findings suggest that besides hypersecretion of cholesterol in bile, chronic inflammation of the gallbladder wall is implicated in the pathogenesis of cholesterol gallstone disease.     

生长因子诱导视网膜色素上皮细胞增殖的协同作用研究

目的从细胞水平探讨生长因子:肿瘤坏死因子-α(tumor necrosis factor,TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)和碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)对视网膜色素上皮(retinal pigment epithelium,RPE)细胞增殖的协同调控作用。方法通过PPE细胞培养，采用氚标胸腺嘧啶核苷(3 H-thymidine,3 H-TdR)掺入测定三种生长因子单用和分别联用诱导RPE细胞DNA合成改变，细胞计数观察RPE细胞生长变化。结果三种生长因子单用均可明显促进RPE细胞DNA合成及细胞数目增加,TNF-α、IL-β和bFGF的3 H-TdR掺入每分钟计数值(counts per minute,cpm)分别是对照组的2.74、2.66和1.69倍(P<0.05)。两种生长因子联用较单用cpm明显提高,其中TNF-α+IL-βcpm是对照组的3.14倍(P<0.05)。三种生长因子联用时cpm是对照组的3.74倍(P<0.05)。结论三种生长因子间存在促RPE细胞增殖的协同作用,这可能是生长因子对RPE细胞增殖的重要调控机制之一。(中华眼底病杂志,1998,14:95-97)     

胆囊切除术中胆管造影对检出胆管结石的价值与指征

分析胆囊切除术时胆管造影检出胆管结石的价值和指征。病例和方法:1988年迄今共行胆囊切除646例。病例分三组,第一组304例兼行胆管造影和探查(造影组);第二组107例未行胆管造影而直接胆道探查(探查组);第三组235例行单纯胆囊切除。结果:第一组胆石检出率为94％;第二组胆石检出率为53％;第三组术后随访有残石2例。结论:术中胆管造影有助于:①降低术后胆道残石率;②避免不必要的胆道探查;③明确胆道解剖变异,有效地预防胆道损伤;④提高对Mirizzi综合征的识别率。