Determination of ochratoxin A in pig tissues by liquid–liquid extraction and clean-up and high-performance liquid chromatography

A fast, simple, and sensitive HPLC–FD method is described for determination of ochratoxin A (OTA) in pig kidney and muscle; a small mass (<2.5 g) of sample and a relatively small volume (<15 mL) of a non-halogenated extraction solvent are required. Ochratoxin B, systematically absent from all the samples investigated, was used as internal standard. Liquid–liquid partition was used for sample clean-up. Recoveries at the 1 ng g^–1 level were 86±15% and 74±8% for kidney and muscle, respectively, and detection limits were 0.14 and 0.15 ng g^–1. Clean-up by solid-phase extraction (SPE) is required for pig liver. A survey of the OTA content of tissues of pigs slaughtered in southern Italy revealed that 52 out of 54 analysed samples were contaminated; the OTA concentration in kidney ranged between 0.26 and 3.05 ng g^–1. The effect of measurement precision on compliance with legal limits is also discussed.     

Monitoring trace elements in selected organs of Antarctic penguin (Pygoscelis adeliae) by plasma-based techniques

A study was undertaken to evaluate the content and distribution of eight key elements, namely, As, Cd, Co, Cu, Hg, Mn, Pb and Se in liver, kidney and muscle of chick individuals of Adélie penguin (Pygoscelis adeliae). Samples were collected during the 2002/2003 austral summer season campaign around Jubany Station (Argentine scientific station), Potter Cove, King George Island. Solutions of organs were prepared by acid-assisted microwave (MW) digestion by employing HNO₃ and H₂0₂. Instrumental techniques selected to analyze the different tissues were inductively coupled plasma optical emission spectroscopy (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS). A wide range of elements retention capacity among the different organs was observed and the ranges ascertained are as follows (in μg g^− 1): As, 0.5 (liver)-0.8 (muscle); Cd, < 0.07 (muscle)-3.4 (kidney); Co, 0.07 (liver)-0.7 (muscle); Cu, 0.6 (muscle)-18 (liver); Hg, 0.2 (kidney)-2.7 (liver); Mn, 1.5 (muscle)-10 (liver); Pb, 0.1 (muscle)-2.0 (liver); Se, 3.0 (muscle)-8.4 (liver). The observed trend in metal accumulation in the three organs of chick penguins was in the order Cu > Mn > Se ? As > Co > Pb ? Cd > Hg. Levels of metals and metalloids were, in general terms, higher in liver that is a specific target organ for metal accumulation. This study aimed at contributing to the establishment of base-line data on potential pollutants of ecotoxicological interest in the Antarctic ecosystem.     

Analysis of γ‐globulin mobility on routine clinical CE equipment: Exploring its molecular basis and potential clinical utility

A study was conducted on the variability of γ‐globulin mobility in serum protein electrophoresis and its molecular basis. We found that the migration time of γ‐globulins can be reproducibly determined (CV=1.1%) on clinical CE equipment. Moreover, we found a significant difference (p<0.001) in the migration of γ‐globulins between chronic liver disease patients (n=98) and a healthy reference group (n=47). Serum immunoglobulins were purified from these patients' sera using protein L ‐agarose and their glycosylation was studied using CE on a DNA sequencer. This glycomics approach revealed that several non‐sialylated N‐glycans show a moderate Pearson correlation coefficient (r=0.2–0.4) with the migration time of γ‐globulins. Their sialylated structures correlate negatively (r=?0.2 to ?0.3). Immunoglobulins are significantly more sialylated in the healthy reference group compared with the patients (p<0.001). We estimated that sialylation heterogeneity contributes about 36% to the molecular variance (carbohydrates and amino acid composition) that affects the electrophoretic mobility of immunoglobulins. This is the first report on the migration time of γ‐globulins on a clinical CE instrument and its potential clinical value to the routinely analyzed serum protein CE profiles.     

Relaxivities of human liver and spleen ferritin

Ferritin, the iron-storing protein of mammals, is known to darken T₂-weighted magnetic resonance images. This darkening can be used to noninvasively measure an organ's iron content. Significant discrepancies exist between T₂ data obtained with ferritin-containing tissues and with aqueous solutions of horse spleen ferritin (HSF). The NMR properties of stable human ferritin have never been studied in aqueous solutions. Relaxometry results on human liver and spleen ferritin are reported here, showing that the relaxation induced in aqueous solutions by human ferritins is comparable to that induced by HSF. As a consequence, the differences between ferritin-containing human tissues and ferritin solutions cannot be attributed to different NMR properties of human and horse ferritins, but probably to a clustering of the protein in vivo.     

小肽免疫抑制剂的活性研究

用标准的Fmoc保护氨基酸Nα氨基的固相法合成了6肽Ac-XCSSXX-NH₂(-CSS-为保守序列,该设计合成的6肽是从若干单克隆中挑选出与IL-2结合力最高的),经HPLC纯化,并通过MS检测.分别以ConA诱导的淋巴细胞转化实验和IL-2诱导的淋巴母细胞转化实验为体外模型,以大鼠肝脏移植为体内模型,观察小肽对移植排斥的影响.在ConA诱导的淋转实验中,加入小肽(250～31.25μg/mL)对淋转反应有明显的抑制作用(P?0.01),在终浓度为31.25μg/mL时,抑制率达到最高.IL-2诱导的淋转实验得到与上述相符的结果,从而进一步表明:小肽是通过抑制IL-2和IL-2R的结合从而实现其免疫抑制作用的.在大鼠肝脏移植模型中:给术后大鼠注射小肽共5d(10mg/kg)可明显延长进行肝移植后大鼠的存活时间.     

电感耦合等离子体发射光谱分析实验小、白鼠骨、肝中超微量稀土元素镧

用外加La量：0、50、500、1000μg/g的饲料分组喂养NIH小白鼠,同时饮用含La量：0、25、250、500μg/mL的蒸馏水;喂养三人月后交配,孕鼠妊娠19天后解剖,分析母鼠肝和骨含La量。结果显示：鼠肝、鼠骨中La含量与单纯饲料外加La量线性相关,且鼠骨La量与肝La量之比,随着La剂量的增加从4.43降到1.50,同时每胎妊娠仔鼠数平均值从13.6降到9.5。     

黄酮类化合物抗鼠肝微粒体脂质过氧化作用的结构与活性关系

黄酮类化合物具有多种药理作用 .由于该类化合物种类多 ,生物活性差别大 ,研究其抗氧化活性与结构的关系 ,将为寻找活性更强的黄酮类物质提供依据 .研究表明 [1] ,黄酮类化合物抗氧化活性与下列结构因素有关 :黄酮母核上的羟基数目及位置 ;B环上是否有邻二羟基 ;C环 2 ,3位是否有双键结构 ,4位是否有羰基结构 ;3 ,5位是否存在羟基 .由于不同研究者所研究的黄酮结构差异较大 ,目前所得到的抗氧化作用的构效关系并不十分一致 ,上述关系也不能全面概括黄酮类抗氧化作用的构效关系 .黄酮类化合物抗氧化活性不仅与其结构有关 ,还与氧自由基的种…     

The study and application of the improved region growing algorithm for liver segmentation

In order to improve the accuracy of the medical image segmentation and reduce the effect of selecting seed points using region growing algorithm, an improved region growing method is proposed in this paper. First, the source images are pre-processed using non-linear mapping method and the region of interest in the liver is selected by man–machine interaction; Quasi-Monte Carlo method is used for generating low-dispersion sequences points in the region of interest and the optical seed points are selected by computing these points; In addition, the region growing criteria is also improved. The improved region growing algorithm is used for segmenting three discontinuous abdomen CT images. Compared with the traditional region growing method, the improved method can get better liver segmentation effects. The proposed method can be effectively applied to liver segmentation and it can improve the accuracy of liver segmentation.     

Two New Dammarane‐Type Triterpenoid Saponins from Gynostemma pentaphyllum

Two new dammarane‐type triterpenoid saponins were isolated from the EtOH extract of Gynostemma pentaphyllum (Thunb .) Makino . Their structural elucidations were accomplished mainly on the basis of the interpretation of spectroscopic data, such as IR, NMR, and HR‐TOF‐MS. Their liver fibrosis inhibitory activities were evaluated against hepatic stellate cells using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay. Thus, G. pentaphyllum can be used as ingredient for ancillary drugs or functional food.