小檗碱对幽门螺旋杆菌感染小鼠胃粘膜损伤和免疫功能的影响机制研究

摘要 目的：探讨小檗碱对幽门螺旋杆菌感染小鼠胃粘膜损伤和免疫功能的影响机制。方法：选择SPF雄性小鼠50只,随机分为5组,包括空白对照组、幽门螺杆菌模型组、小檗碱低剂量组（25 mg/mL,A组）、中剂量组（50 mg/mL,B组）和高剂量组（100 mg/kg/d,C组）。空白组大鼠腹腔注射等容量的生理盐水,其余组使用口服幽门螺杆菌的方法建立幽门螺旋杆菌感染小鼠模型。进行胃黏膜上皮细胞存活率和凋亡率检测,同时测定胃黏膜上皮细胞凋亡蛋白水平、炎症因子水平、免疫功能以及IL-4/STAT6 mRNA水平。结果：模型组、小檗碱低剂量组、中剂量组和高剂量组胃黏膜上皮细胞存活率均显著低于空白对照组（P<0.05）;且随着小檗碱剂量的增加,细胞存活率逐渐升高（P<0.05）;模型组、小檗碱低剂量组、中剂量组和高剂量组胃黏膜上皮细胞凋亡率均显著高于空白对照组（P<0.05）;且随着小檗碱剂量的增加,细胞凋亡率逐渐降低（P<0.05）;与模型组比较,小檗碱低、中、高剂量组小鼠胃黏膜上皮细胞凋亡蛋白Bax和Cl-caspase-3的水平、TNF-α、IFN-γ、IL-10和TGF-β的水平均显著降低（P<0.05）,且随着小檗碱剂量的增加,Bax和Cl-caspase-3的水平、TNF-α、IFN-γ、IL-10和TGF-β的水平逐渐降低（P<0.05）;与模型组比较,小檗碱低、中、高剂量组上清液中CD3⁺、CD4⁺和CD8⁺的水平、IL-4 mRNA和STAT6 mRNA均显著升高（P<0.05）,且随着小檗碱剂量的增加,CD3⁺、CD4⁺和CD8⁺水平、IL-4 mRNA和STAT6 mRNA逐渐升高（P<0.05）。结论：小檗碱能够减轻幽门螺旋杆菌感染小鼠胃粘膜损伤,提升免疫功能,可能与IL-4/STAT6信号通路有关。     

毛蕊异黄酮抑制SIRT1促乳腺癌细胞MCF-7凋亡

目的:探讨毛蕊异黄酮促乳腺癌细胞MCF-7凋亡的机制。方法:MTT检测低、中、高(10μM,50μM,100μM)剂量的毛蕊异黄酮对细胞活力的影响;Tunel检测毛蕊异黄酮对细胞凋亡的影响;Western blot检测SIRT1,p53和cleaved caspase-3的蛋白表达;Real-time PCR检测caspase-3 mRNA的表达。结果:毛蕊异黄酮能够剂量依赖性地降低细胞活力,100μM剂量组的毛蕊异黄酮显著地促进肿瘤细胞凋亡并降低SIRT1,增加p53和cleaved caspase-3的蛋白表达。SIRT1抑制剂烟酰胺(Nicotinamide,NAM,300μM)组与毛蕊异黄酮处理组相比显著地抑制SIRT1的蛋白表达,p53和cleaved caspase-3蛋白表达水平进一步增加;SRT1720(SIRT1特异性激动剂)与毛蕊异黄酮共孵育组逆转SIRT1蛋白表达,降低p53和cleaved caspase-3的蛋白水平。结论:毛蕊异黄酮促进肿瘤细胞MCF-7的凋亡,部分可能是通过降低SIRT1的表达水平,从而增加p53和cleaved caspase-3的蛋白表达促进细胞凋亡。     

过量大黄对小鼠肝脏细胞的毒性作用

目的探讨不同剂量的大黄对小鼠肝脏细胞的损伤及其机理,为大黄的安全用药提供理论依据。方法采用大、中、小、最小剂量的大黄灌胃昆明小鼠,观察一般状态,进行肝脏组织切片HE染色、酶指标生化检测及TNFαmRNA半定量检测。结果①小鼠一般状况随大黄剂量的增加而恶化。②小鼠ALT及γ-GT随大黄剂量增加而增高,除正常对照组和最小剂量组外,其余各组之间差异均达显著水平。③从小剂量组开始,小鼠肝脏出现脂肪变性,且随大黄剂量增加而加重。④从小剂量组开始,TNFα表达明显升高,且随大黄剂量增加而增高。结论8g/Kg/d剂量大黄对肝脏具有毒害作用,毒害作用随大黄剂量增加而加剧,过量大黄对肝脏的毒害作用主要表现为肝细胞脂肪变性。TNFα参与了过量大黄对肝脏的毒害过程,是造成肝细胞脂肪变性的损伤因子之一。     

孕期高果糖摄入对胚胎发育和胎盘血管因子的研究

目的：探讨孕期高果糖摄入对胚胎发育的影响及胎盘血管因子对其影响的机制。方法：成年雌性SD大鼠与正常饮食雄性大鼠进行交配,孕鼠随机分为5组,分别是对照组、正常剂量果糖组、高剂量果糖组、高剂量蔗糖组和超高剂量果糖组,在孕期分别给予1mL去离子水、1.6g/kg、4.8g/kg、4.5g/kg和8.0g/kg的果糖水和蔗糖水灌胃,连续干预3w,于第3w末处死孕鼠,麻醉、取血并剖取胎鼠,检查胎鼠的一般状况、着床、死胎、吸收胎、外观畸形等,制作子代内脏和骨骼标本,观察内脏和骨骼的情况;称量胎重和胎盘重,观察各组间胎盘血管内皮生长因子（VEGF）、血管内皮生长因子受体-1（sFlt-1）和一氧化氮（NO）的变化。结果：对孕鼠连续进行3w的果糖干预后,超高剂量果糖组子代出生体重显著低于对照组（P＜0.05）;高剂量果糖组、高剂量蔗糖组和超高剂量果糖组子代与对照组和正常剂量果糖组相比,死胎数和吸收胎数显著增加（P＜0.05）;但各组子代并没有发生骨骼畸形和内脏出血。超高剂量果糖组胎盘重量显著低于对照组（P＜0.05）;高剂量果糖组、高剂量蔗糖组和超高剂量果糖组胎盘中VEGF和NO水平显著低于对照组和正常剂量果糖组（P＜0.05）;胎盘中sFlt-1水平明显高于对照组和正常剂量果糖组（P＜0.05）。结论：孕期高果糖摄入可增加子代发生死胎和吸收胎等不良结局的风险,胎盘中VEGF、NO的水平降低和sFlt-1水平增高可能是导致子代发生不良结局的原因,具体机制值得深入研究。     

多奈哌齐治疗阿尔兹海默症患者的临床剂量使用探讨

目的:评价多奈哌齐治疗阿尔兹海默症(AD)的疗效及疗效与用药剂量的关系,探讨检测血清中胰岛素样生长因子-I(IGF-I)来指导治疗剂量的可行性。方法:87例轻中度的AD患者,患者使用5 mg/d多奈哌齐疗效不佳。在增加剂量之前,根据血清胰岛素样生长因子-I(IGF-I)水平和简易智力状态检查表(MMSE)得分之间的一致性,将患者分为3组。A组:n=27,IGF-I≤99ng/m L,MMSE≤37;B组:n=33,IGF-I≤99 ng/m L,MMSE18;C组:n=27,IGF-I99 ng/m L,MMSE18。A、B组中,血清IGF-I水平显著低于C组。试验开始后将多奈哌齐的剂量从5 mg/d增加到10 mg/d,服用12周后,观察血清IGF-I水平同MMSE和阿尔兹海默症评定量表(ADAS)得分的相关性及三组患者的临床改善情况。结果:血清IGF-I水平同认知功能有明显相关性。IGF-I同MMSE正相关(r=0.478,P=0.036),IGF-I同ADAS得分负相关(r=-0.464,P=0.029)。增加多奈哌齐(10 mg/d)剂量治疗后,只有A组患者MMSE得到显著改善。A组患者对治疗的敏感性显著高于B、C组患者。结论:血清中IGF-I水平和MMSE分值可以做为一种标志物,判断对低剂量多奈哌齐(5 mg/d)无效的轻中度AD患者,能否采用高剂量多奈哌齐(10 mg/d)进行治疗。     

Iuteolin对糖尿病大鼠心脏功能的保护作用及其可能机制

目的：研究Iuteolin对链脲佐菌素诱导的Ⅰ型糖尿病大鼠心功能及心肌线粒体氧化应激的影响。方法：雄性SD大鼠,随机分成正常对照组,Iuteolin对照纽,糖尿病模型组,低剂量Iuteolin（10ms／（kg·d））灌胃治疗组,高剂量Iuteolin（100ms／（kg·d））灌胃治疗组。各组大鼠饲养8周后,测体重、血糖、心功能、左心室重量、心肌胶原含量及活性氧自由基（ROS）水平,分离心肌线粒体检测ROS水平、超氧化物歧化酶（SOD）活性及线粒体肿胀程度。结果：Iuteolin处理对糖尿病大鼠血糖无明显影响,但可减少糖尿病引起的体重下降。高剂量Iuteolin可显著减小糖尿病大鼠心室与体重比值,提高左室发展压,降低左室舒张末压。高剂量Iuteolin治疗后,糖尿病大鼠心肌ROS及胶原含量。心肌线粒体ROS水平与肿胀程度均明显下降,心肌线粒体SOD活性明显增加。结论：Iuteolin处理可显著改善糖尿病大鼠心功能．其机制可能与减轻心肌线粒体氧化应激及抑制线粒体肿胀有关。     

辛伐他汀治疗老年高血脂患者疗效与安全性的最佳剂量研究

目的:观察不同剂量辛伐他汀治疗老年高血脂患者疗效与安全性。方法:将纳入研究的80例老年高血脂患者随机分为高剂量组和低剂量组,各40例。高剂量组给予辛伐他汀剂40 mg/日,低剂量组给予20 mg/日。治疗2个月后观察疗效、血脂水平变化情况,并统计两组不良反应的发生情况。结果:高剂量组总有效率95%显著高于低剂量组的80%(P0.05);治疗后,两组TG、TC、LDL-C、HDL-C水平均有改善,与本组治疗前比较均有显著性差异(P均0.05),且高剂量组上述指标改善明显优于低剂量组(P均0.05);治疗期间两组不良反应发生率无统计学意义(P0.05)。结论:辛伐他汀高剂量(40 mg/日)治疗老年高血脂的疗效优于低剂量(20 mg/日),且不增加不良反应发生的风险。     

双歧杆菌对肠上皮细胞生长和白介素-8分泌功能的影响

目的探讨双歧杆菌对人肠上皮细胞株HT29生长及其IL-8分泌水平的影响。方法HT29细胞在96孔板上生长24h后分为正常细胞对照组、高剂量双歧杆菌共培养组（细菌终浓度为1×10^10CFU／m1）、低剂量双歧杆菌共培养组（细菌终浓度为1×10^6CFU／ml）、轮状病毒感染对照组,分别加入不同剂量双歧杆菌和感染轮状病毒共培养,继续培养24h,光镜下观察细胞生长状态,MTT比色法检测细胞活性情况,ELISA检测细胞培养上清中IL-8表达水平。结果光镜下观察到双歧杆菌与HT29细胞共培养后细胞形态无明显改变,共培养24h后MTT检测双歧杆菌对HT29细胞增殖和调亡无明显影响,但轮状病毒感染对照组细胞病变脱落,活细胞数量明显减少。共培养6h,其余3组细胞培养上清中IL-8分泌较正常细胞对照组增加（P〈0．05）,高剂量双歧杆菌组增加较低剂量双歧杆菌组差异有显著性（P〈0．05）,但两个剂量组均明显低于轮状病毒感染阳性对照组的IL-8分泌增加水平（P〈0．05）;感染后24h,细胞培养上清中IL-8分泌水平高于正常细胞对照组（P〈0．05）,但高、低剂量双歧杆菌组之间差异无显著性（P〉0．05）,两个剂量组IL-8分泌增加水平均明显低于轮状病毒感染阳性对照组（P〈0．01）。结论两歧双歧杆菌共培养不影响HT29细胞的生长,双歧杆菌能够促进HT29细胞分泌细胞因子IL-8,但明显低于致病微生物刺激引起的细胞因子分泌水平改变,这种促进作用无时间-剂量依赖关系,提示双歧杆菌与肠道内致病微生物对肠道免疫功能的影响不同,双歧杆菌促进肠上皮细胞分泌IL-8可能与其参与的肠道黏膜免疫系统发育成熟相关。     

一种狂犬病毒疫苗佐剂的制备及其免疫效果研究

目的:以角鲨烯、山梨醇、吐温为组分,在琥珀酸缓冲液中混和甲型副伤寒沙门菌鞭毛蛋白制备复合佐剂Nano-fla,评价该佐剂对人二倍体狂犬疫苗的免疫效果和安全性。方法:以人二倍体细胞制备的狂犬灭活疫苗为抗原,BALB/c小鼠设置PBS对照组、全剂量疫苗组、半剂量疫苗组、低剂量佐剂组(含半剂量抗原+5μg鞭毛蛋白)、中等剂量佐剂组(含半剂量抗原+10μg鞭毛蛋白),免疫程序为在0、3、7 d肌肉注射,并在首针免疫后的第7、14 d尾静脉采血分离血清,通过快速免疫荧光灶抑制实验检测中和抗体,通过酶联免疫斑点实验检测细胞因子水平。结果:首针免疫后第7 d,中等剂量佐剂组的中和抗体达保护效力水平,显著高于全剂量疫苗组和低剂量佐剂组;第14 d时中等剂量佐剂组的IgG抗体浓度显著高于全剂量疫苗对照组;第14 d中等剂量佐剂组与全剂量疫苗组相比,分泌IFN-γ和IL-4的淋巴细胞数量显著增加。结论:复合佐剂Nano-fla应用到狂犬疫苗中,能有效刺激小鼠体液免疫和细胞免疫应答,更早地产生中和抗体,且能有效降低抗原用量,具有潜在应用价值。     

不同剂量乌司他汀对急性重症胆管炎大鼠肝屏障的保护作用

目的:探讨不同剂量乌司他汀对急性重症胆管炎(ACST)大鼠肝屏障的保护作用。方法:60只雄性SD大鼠通过手术造成胆总管梗阻并注射细菌内毒素造成ACST模型,造模48 h后处死,随机分成5组,每组12只,分别进行假手术(SN组)、ACST造模手术(ACST组)、ACST造模手术+乌司他汀治疗,依据乌司他汀浓度分为低(20000 U/kg·d)(ASCT-L组)、中(40000 U/kg·d)(ASCT-M组)、高(80000 U/kg·d)(ASCT-H组)三组,采集血液进行总胆红素(TB)、谷丙转氨酶(ALT)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10)和肿瘤坏死因子-α(TNF-α)的检测,采集部分肝组织进行组织染色,检测肝细胞凋亡率并分析紧密连接蛋白Occludin和ZO-1基因表达水平。结果:与SN组比较,造模后各组大鼠TB和ALT水平均显著升高(均P0.05),乌司他汀治疗后各组大鼠TB和ALT水平随剂量增加而明显降低,各组间差异均有统计学意义(均P0.05);造模后大鼠IL-6、IL-10和TNF-α水平均显著升高,乌司他汀治疗后各组大鼠IL-6和TNF-α水平随剂量增加而降低,IL-10水平随剂量增加而升高,不同剂量间差异有统计学意义(均P0.05);ACST组肝细胞凋亡率显著高于SN组,Occludin和ZO-1基因表达水平显著降低(P0.05);乌司他汀治疗后各组大鼠肝细胞凋亡率有不同程度的降低,Occludin和ZO-1基因表达水平有不同程度的升高(P0.05)。结论:乌司他汀治疗ACST大鼠疗效显著,对肝屏障功能有良好的保护作用,其治疗效果与剂量呈现明显的相关性,其机制及合适的给药剂量值得进一步研究。     

Using matrix summation method for three dimensional dose calculation in brachytherapy

AimThe purpose of this study is to calculate radiation dose around a brachytherapy source in a water phantom for different seed locations or rotation the sources by the matrix summation method.BackgroundMonte Carlo based codes like MCNP are widely used for performing radiation transport calculations and dose evaluation in brachytherapy. But for complicated situations, like using more than one source, moving or rotating the source, the routine Monte Carlo method for dose calculation needs a long time running.Materials and methodsThe MCNPX code has been used to calculate radiation dose around a ¹⁹²Ir brachytherapy source and saved in a 3D matrix. Then, we used this matrix to evaluate the absorbed dose in any point due to some sources or a source which shifted or rotated in some places by the matrix summation method.ResultsThree dimensional (3D) dose results and isodose curves were presented for ¹⁹²Ir source in a water cube phantom shifted for 10 steps and rotated for 45 and 90° based on the matrix summation method. Also, we applied this method for some arrays of sources.ConclusionThe matrix summation method can be used for 3D dose calculations for any brachytherapy source which has moved or rotated. This simple method is very fast compared to routine Monte Carlo based methods. In addition, it can be applied for dose optimization study.     

The variance-covariance method: Microdosimetry in time-varying low dose-rate radiation fields

Summary The variance-covariance method is employed at low doses and in radiation fields of low dose rates from an²⁴¹Am (4 nGy/s) and a⁹⁰Sr (300 nGy/s) source. The preliminary applications and results illustrate some of the potential of the method, and show that the dose average of lineal energy or energy imparted can be determined over a wide range of doses and dose rates. The dose averages obtained with the variance-covariance method in time-varying fields, for which the conventional variance method is not suitable, agree well with results obtained under the condition of constant dose rate. The results are compared to data obtained in terms of the conventional single-event measurements. The method has evident advantages, such as facility and speed of measurement.     

Cancer phase I trial design using drug combinations when a fraction of dose limiting toxicities is attributable to one or more agents

Drug combination trials are increasingly common nowadays in clinical research. However, very few methods have been developed to consider toxicity attributions in the dose escalation process. We are motivated by a trial in which the clinician is able to identify certain toxicities that can be attributed to one of the agents. We present a Bayesian adaptive design in which toxicity attributions are modeled via copula regression and the maximum tolerated dose (MTD) curve is estimated as a function of model parameters. The dose escalation algorithm uses cohorts of two patients, following the continual reassessment method (CRM) scheme, where at each stage of the trial, we search for the dose of one agent given the current dose of the other agent. The performance of the design is studied by evaluating its operating characteristics when the underlying model is either correctly specified or misspecified. We show that this method can be extended to accommodate discrete dose combinations.     

A Bayesian hierarchical method to account for random effects in cytogenetic dosimetry based on calibration curves

The dicentric chromosome assay (DCA) is one of the most sensitive and reliable methods of inferring doses of radiation exposure in patients. In DCA, one calibration curve is prepared in advance by in vitro irradiation to blood samples from one or sometimes multiple healthy donors in considering possible inter-individual variability. Although the standard method has been demonstrated to be quite accurate for actual dose estimates, it cannot account for random effects, which come from such as the blood donor used to prepare the calibration curve, the radiation-exposed patient, and the examiners. To date, it is unknown how these random effects impact on the standard method of dose estimation. We propose a novel Bayesian hierarchical method that incorporates random effects into the dose estimation. To demonstrate dose estimation by the proposed method and to assess the impact of inter-individual variability in samples from multiple donors on the estimation, peripheral blood samples from 13 occupationally non-exposed, non-smoking, healthy individuals were collected and irradiated with gamma rays. The results clearly showed significant inter-individual variability and the standard method using a sample from a single donor gave anti-conservative confidence interval of the irradiated dose. In contrast, the Bayesian credible interval for irradiated dose calculated by the proposed method using samples from multiple donors properly covered the actual doses. Although the classical confidence interval of calibration curve with accounting inter-individual variability in samples from multiple donors was roughly coincident with the Bayesian credible interval, the proposed method has better reasoning and potential for extensions.     

A new evaluation method of target volume coverage and homogeneity for IMRT treatment planning

Based on the functional approximation of a target volume DVH (TV-DVH) to a modified step function, we propose a new index that indicates the degrees of dose coverage and homogeneity for target volume reached in clinical routines. Forty-seven IMRT patient plans are included in the analysis to explore the efficiency of the proposed method. The new index, named s-index, was defined to vary from 0:05 for clinically acceptable TV-DVH at our institution and showed the ability to give the user an idea whether the degree of dose coverage and homogeneity for target volume were adequate when the user-defined criteria had been in place. The result shows that the lower value of s-index indecates the higher dose coverage for the tumor volume and/or the higher dose homogeneity showing the faster fall-off rate at the percentage dose higher than 100%. In addition to the quantification of dose coverage and homogeneity is has been also shown that s-index is more accurate in evaluating the dose homogeneity in tumor volume than the conventional method. The proposed method has demonstrated the effectiveness in evaluating TV-DVH in terms of simple index and supplements currently used indices by providing complete information of a DVH curve in a treatment plan.     

蒙特卡罗法在化感作用全区间抑制强度评估(wholerange assessment)中的应用

植物化感作用的强弱与化感物质的作用浓度相关.化感作用全区间抑制强度指数(Whole-range assessmentindex)是用于评估植物在一定的化感物质作用范围内所受化感作用总体抑制程度的一种方法.在对非线性剂量响应进行曲线拟合的基础上,本研究应用蒙特卡罗模拟法为计算化感作用全区间抑制强度指数提供了一种科学的数学计算方法,并应用该计算方法分析了番茄水浸提液对生菜、萝卜、白菜、菜心、包心菜、豆角和水稻的化感作用强度.     

Biodosimetry estimate for high-LET irradiation

The purpose of this paper is to prepare for an easy and reliable biodosimeter protocol for radiation accidents involving high-linear energy transfer (LET) exposure. Human peripheral blood lymphocytes were irradiated using carbon ions (LET: 34.6 keV μm⁻¹), and the chromosome aberrations induced were analyzed using both a conventional colcemid block method and a calyculin A induced premature chromosome condensation (PCC) method. At a lower dose range (0–4 Gy), the measured dicentric (dics) and centric ring chromosomes (cRings) provided reasonable dose information. At higher doses (8 Gy), however, the frequency of dics and cRings was not suitable for dose estimation. Instead, we found that the number of Giemsa-stained drug-induced G2 prematurely condensed chromosomes (G2-PCC) can be used for dose estimation, since the total chromosome number (including fragments) was linearly correlated with radiation dose (r = 0.99). The ratio of the longest and the shortest chromosome length of the drug-induced G2-PCCs increased with radiation dose in a linear-quadratic manner (r = 0.96), which indicates that this ratio can also be used to estimate radiation doses. Obviously, it is easier to establish the dose response curve using the PCC technique than using the conventional metaphase chromosome method. It is assumed that combining the ratio of the longest and the shortest chromosome length with analysis of the total chromosome number might be a valuable tool for rapid and precise dose estimation for victims of radiation accidents.     

A “quality-control-based correction method” for displayed dose indices on CT scanner consoles in patient dose surveys

PurposeA new quality-control-based (QC-based) method is introduced to obtain correction factors to be applied to displayed patient dose indices (CTDI_Vol and DLP) on CT scanner consoles to verify improvement of dose surveys for diagnostic reference levels (DRLs) determination.MethodAn available data-base of QC documents and reports of 57 CT scanners in Tehran, Iran was used to estimate CTDI_Vol, DLP and relevant correction factors for three CT examination types including head, chest and abdomen/pelvis. The correction factor is the ratio of QC-based estimated dose to displayed dose. A dose survey was performed by applying on-site “data collection method” and correction factors obtained in order to select CT scanners in three modes for determination of CT DRLs by inclusion of: (a) all CT scanners before displayed dose indices were corrected (57), (b) only CT scanners calibrated by QC experts (41) and (c) all CT scanners after displayed dose indices were corrected (57).ResultsFor the 41 CT scanners, correction factors of three examination types obtained in this study are within the acceptance tolerance of IAEA HHS-19. The correction factors range from 0.45 to 1.7 (average of 3 examinations) which is due to the change in the calibrated value of CTDI_Vol over extended time. The DRL differences in three modes are within ±1.0% for CTDI_Vol and ±12.4% for DLP.ConclusionsThe “QC-based correction method” applied to mode (c) has improved the DRLs obtained by other two modes. This method is a strong alternative to “direct dose measurement” with simplicity and cost effectiveness.