核黄素缺乏大鼠红细胞维生素E水平的变化及脂质过氧化关系的研究

对两组大鼠分别喂饲核黄素缺乏（ＲＤ）膳和核黄素添加（Ｒ８，２２ｍｇ／ｋｇ饲料）膳８周后，测定了两组大鼠的红细胞维生素Ｅ（ＲＢＬＶｅ）、红细胞超氧化物歧化酶（ＳＯＤ）和红细胞丙二醛（ＭＤＡ）的水平。结果发现：ＲＤ组ＲＢＣＶｅ水平（４．７１７３±０．７７１０ｍｇ／ｇ蛋白质）显著低于ＲＳ组（５。３８６８±１．１５３７ｍｇ／ｇ蛋白质，Ｐ＜０．０５）。而ＲＤ组的ＲＢＣＳＯＤ（７７４５．２±６１０．１ｕ／ｇ蛋白质）和ＭＤＡ（０．６８６８±０．１３７２μｇ／ｇ蛋白质）则分别显著低于和高于ＲＳ组（８２６８．５±３０１．０ｎｕ／ｇ蛋白质，０．５５４８±０．０９８０，Ｐ＜０．０５）。研究提示，核黄素缺乏引起细胞膜脂质过氧化加重可能ＲＢＣＶｅ消耗增加。     

盐亭县核黄素强化盐干预试验人群肿瘤发病情况

[目的]探讨核黄素强化盐干预试验对人群肿瘤发病率的影响.[方法]对盐亭县核黄素强化盐干预试验人群干预期(1992～1996)和干预停止期(1997～2001)的肿瘤发病资料进行分析.[结果]试验组男性食管癌、肺癌、结直肠癌,女性食管癌、白血病、宫颈癌发病率在干预期高于对照组,而在干预停止期低于对照组.两组人群10年的肿瘤发病资料比较,试验组除胃癌外其他肿瘤发病率均低于对照组,尤其是食管癌和宫颈癌发病率明显低于对照组,而两组人群中肺癌、结直肠癌发病率都上升,但试验组的上升幅度低于对照组.[结论]试验组与对照组肿瘤发病率的差异,提示补充核黄素有利于降低肿瘤的发病风险,值得在更大范围的肿瘤高危人群中推广.     

核黄素缺乏对人成淋巴细胞株遗传稳定性及细胞毒性影响初探

微量营养素(micronutrient)是许多酶的底物或辅酶成分,当其涉及维持基因组稳定性相关的生化反应时,供给状况及代谢特点就可能影响基因组稳定性,构成肿瘤风险因素[1,2]。其缺乏或代谢异常可使基因组稳定性下降,提高肿瘤危险度[4,5]。核黄素(riboflavin,VB2)是黄素腺嘌呤二核苷酸的前体,参与机体生物氧化反应及能量代谢,VB2缺乏可引起亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)的活力降低,引起叶酸代谢异常[6]。当叶酸水平较低或MTHFR活性降低时,通过同型半胱氨酸(homocysteine,HCy)合成S-腺苷甲硫氨酸(S-aden…     

Endoscopic transnasal canaliculorhinostomy for refractory common canalicular obstruction with an unidentifiable lacrimal sac

AIM: To compare the safety and efficacy of conventional versus accelerated (9 mW/cm2) CXL in progressive keratoconus at the 2-year follow-up. METHODS: In this prospective study, consecutive progressive keratoconus patients were randomized to receive either conventional CXL (CCXL) or accelerated CXL (ACXL, using hydroxypropyl methylcellulose-assisted riboflavin imbibition for 10min) at 9 mW/cm2. Visual, refractive, keratometric, topographic, and aberrometric outcomes and stromal demarcation line depth (DLD) measurements were compared at the end of a 2-year follow-up. RESULTS: Thirty-two eyes from 32 patients in the CCXL and 27 eyes from 27 patients in the ACXL groups completed 2-year follow-ups. At 2 years post-CXL, both uncorrected and corrected visual acuities improved significantly in both groups. The improvements in keratometric readings, flattening rate (flattening of the Kmax more than 1D), 3 topographic indices, and vertical coma were significantly better in the CCXL group compared to the ACXL group (P<0.05). The DLD as measured by anterior segment optical coherence tomography or in vivo confocal microscopy was better detectable and significantly deeper in the CCXL group compared to the ACXL group. The deeper DLD was found to be significantly correlated with improvements in the mean keratometry measurements. Progression was noted in 11.1% of eyes in the ACXL group, whereas progression was not observed in any patient eye in the CCXL group. CONCLUSION: In this prospective randomized study, ACXL was less effective in halting the progression of keratoconus at a 2-year follow-up compared to CCXL.     

Riboflavin concentration in corneal stroma after intracameral injection

AIM:To evaluate the enrichment of riboflavin in the corneal stroma after intracameral injection to research the barrier ability of the corneal endothelium to riboflavin in vivo.METHODS:The right eyes of 30 New Zealand white rabbits were divided into three groups. Different concentrations riboflavin-balanced salt solutions (BSS) were injected into the anterior chamber (10 with 0.5%, 10 with 1%, and 10 with 2%). Eight corneal buttons of 8.5 mm in diameter from each group were dissected at 30min after injection and the riboflavin concentrations in the corneal stroma were determined using high-performance liquid chromatography (HPLC) after removing the epithelium and endothelium. The other two rabbits in every group were observed for 24h and sacrificed. As a comparison, the riboflavin concentrations from 16 corneal stromal samples were determined using HPLC after instillation of 0.1% riboflavin-BSS solution for 30min on the corneal surface (8 without epithelium and 8 with intact epithelium).RESULTS: The mean riboflavin concentrations were 11.19, 18.97, 25.08, 20.18, and 1.13 μg/g for 0.5%, 1%, 2%, de-epithelialzed samples, and the transepithelial groups, respectively. The color change of the corneal stroma and the HPLC results showed that enrichment with riboflavin similar to classical de-epithelialized corneal collagen crosslinking (CXL) could be achieved by intracameral1% riboflavin-BSS solution after 30min; the effect appeared to be continuous for at least 30min.CONCLUSION:Riboflavin can effectively penetrate the corneal stroma through the endothelium after an intracameral injection in vivo, so it could be an enhancing method that could improve the corneal riboflavin concentration in transepithelial CXL.     

Corneal collagen cross‐linking for infectious keratitis: an update of clinical studies

Collagen cross‐linking (CXL) with ultraviolet light‐activated riboflavin is a corneal surface procedure developed for the treatment of keratoconus and corneal ectasia. With the known microbicidal and corneal stiffening effects of ultraviolet irradiation and photoactivated riboflavin, it has recently been introduced for the management of infectious keratitis, especially for ulcers resistant to antimicrobial therapy or associated with corneal melting. Various authors have attempted to use CXL as an adjunctive, salvage or even as the sole treatment for infectious corneal ulcers. The aim of this review was to provide a summary of the clinical studies in the literature. It is worth noting that there is still no consensus on the treatment protocol of CXL against infectious keratitis. The disparities in outcome measures, treatment protocol and study design can confound the interpretation and hamper the generalization of the study results. Based on current evidence, the role of CXL in infectious keratitis remained unclear despite the reported success in some clinical cases. Further investigations are warranted concerning the efficacy and safety of treating infectious keratitis with CXL.     

UHILIC-MS/MS法同时测定复方三维右旋泛酸钙糖浆中5种维生素的含量

目的 建立一种超高效亲水作用色谱串联三重四极杆质谱法（UHILIC-MS/MS）,同时测定复方三维右旋泛酸钙糖浆中维生素B₁、维生素B₂、维生素B₆、烟酰胺和泛酸钙的含量。方法 采用超高效液相色谱仪,Waters ACQUITY BEHHILIC Amide色谱柱（2.1 mm×100 mm,1.7 μm）,以90%乙腈（含0.5%甲酸）-10 mmol/L甲酸铵水（含0.5%甲酸）为流动相,进行梯度洗脱,流速0.30 ml/min;在电喷雾（ESI）正离子模式下,用多反应监测（MRM）模式进行含量测定。结果 在5 min内,样品中5种维生素分别在各自考察的浓度范围内呈良好的线性关系,相关系数（r）均大于0.998 4;整体加样回收率在93.27%~100.39%之间,RSD为1.41%~4.96%;10批样品中维生素B₁、维生素B₂、维生素B₆、烟酰胺、泛酸钙的含量测定结果分别为32.40~38.91、7.002~8.462、9.677~11.17、33.64~39.58、3.276~3.771 mg/250 g。结论 本研究建立的UHILIC-MS/MS方法可快速实现对复方三维右旋泛酸钙糖浆中5种维生素类成分定性鉴定或定量检测,为复方三维右旋泛酸钙糖浆的开发利用和质量评价提供了可靠的技术检测方法。