生物素标记HBV DNA探针在肝石蜡切片上作原位杂交技术的研究——各型肝病时HBV DNA的定位及形态

报告用生物素标记HBV DNA探针原位杂交技术,现察75例慢性肝病者肝石蜡切片上HBV DNA定位及形态。共检出HBV DNA阳性者25/75例(33.33％)。其中:CPH2/7例、CAH10/21例、肝硬化0/3例、SS4/11例、无症状HBsAg携带者4/21例和HCC5/12例。HBVDNA在肝切片上呈棕黄色粗颗粒状,主要分布于肝细胞浆内,个别核内亦可见少数浅染棕黄色颗粒。阳性肝细胞分布有三种形式:Ⅰ型(弥漫型):25例中有4例(16％),Ⅱ型(局灶型):20例(80％),Ⅲ型(散在型):仅1例(4％)。颗粒在胞浆内亦有a型(密集)和b型(稀疏)之分。各型乙型肝炎HBV DNA在肝切片上定位与分布不完全相同,可能表示不同的病毒感染状态和复制的活跃程度。HCC只在癌旁肝组织内查见HBV DNA。     

Interference of sugars with the binding of biotin to streptavidin and avidin

Streptavidin and avidin have found widespread use as detection reagents in immunology, biochemistry and cell biology due to their high affinity binding to biotin, but the cellular functions of these proteins are not known. We have found that various sugars interfere with the binding of streptavidin and avidin to biotin. Mannose was most effective in inhibiting the binding to biotin followed by other saccharides. The inhibitory effect is most probably due to interactions of the sugars with residues in the binding pocket of streptavidin and avidin for biotin. These results show that great caution has to be exercised in the evaluation of experiments conducted with these detection reagents in the presence of sugars.     

Holocarboxylase synthetase deficiency: Early diagnosis and management of a new case

We present a new case of holocarboxylase synthetase (HCS) deficiency, a rare autosomal recessive metabolic disorder, causing the early-onset form of multiple carboxylase deficiency. The patient was born at term of healthy consanguineous parents after an uncomplicated pregnancy. On the 2nd day of life she refused oral feeding, became tachydyspnoeic and showed excessive weight loss. Laboratory studies showed metabolic acidosis, marked lactic acidaemia, hyperammonaemia and increased urinary excretion of 3-hydroxyisovaleric acid, 3-methylcrotonyglycine, 3-hydroxypropionic acid and methylcritric acid. Peritoneal dialysis combined with oral supplementation of biotin (10 mg/day) started on the 3rd day of life resulted in rapid clinical recovery and normalisation of biochemical parameters. HCS deficiency was established in lymphocytes and skin fibroblasts. The activities of all biotin-dependent carboxylases were severely decreased in fibroblasts grown in medium with moderate biotin concentration (10^–8 mol/l) but normal in a high biotin medium (10^–5 mol/l). Mitochondrial carboxylase activities in lymphocytes were 23%–29% of mean normal during therapy with 20 mg of biotin/day, with the higher dose of 40 mg/day they were within (3-methylcrotoryl-CoA carboxylase, pyruvate carboxylase) or slightly below (propionyl-CoA carboxylase) the normal range. At the age of 3 years the patient's physical and psychomotor development are normal. Early biotin supplementation should be considered in newborns with lactic acidosis and organoaciduria until a final diagnosis has been established. Furthermore, the required individual dose of biotin has to be carefully evaluated biochemically for the individual patient.     

载BDNF脂质体纳米微粒脂膜微泡超声造影剂的制备与初步评价

目的 探索制备一种新型的耦连包载BDNF脂质体纳米颗粒的脂膜微泡超声造影剂(BDNF-UMCA)。方法 以冷冻干燥法在“脂氟显”制备的基础上加入一定比例的含生物素化棕榈酰磷脂酰甘油钠-聚乙二醇2000-生物素[DPPG-PEG(2000)-Biotin]制备含生物素的脂质超声微泡造影剂,通过链亲和素来耦连含生物素化PEG载BDNF脂质体纳米微粒制备BDNF-UMCA,检测其理化性质、载药量、包封率、稳定性和体内声学特性进行检测。结果 BDNF-UMCA平均粒径4.2±0.79 μm,浓度为1.02×10₉/ml;总药物含量为1.18±1.96 mg/mL,包封率为71.6±2.6%;BDNF-UMCA在4℃条件下,平均粒径和包封率均无明显的变化;在24℃条件下,载BDNF脂质体纳米微粒的平均粒径随时间逐渐增大,第1、3、5、7天的粒径与初始粒径比较具有明显的统计学差异(均P<0.05),包封率在24℃下各个时间点无明显的统计学差异(均P>0.05);BDNF-UMCA能显著增强实验动物肝脏显影,平均峰值强度为21.4±0.9 dB,平均达峰时间为4.7±0.4 s。结论 应用生物素-亲和素偶联可成功制备载BDNF脂质体纳米微粒的脂膜超声微泡造影剂,为靶向显影及药物通过血脑屏障释放提供工具。     

Probing the biofunctionality of biotinylated hyaluronan and chondroitin sulfate by hyaluronidase degradation and aggrecan interaction

Molecular interactions involving glycosaminoglycans (GAGs) are important for biological processes in the extracellular matrix (ECM) and at cell surfaces, and also in biotechnological applications. Enzymes in the ECM constantly modulate the molecular structure and the amount of GAGs in our tissues. Specifically, the changeable sulfation patterns of many GAGs are expected to be important in interactions with proteins. Biotinylation is a convenient method for immobilizing molecules to surfaces. When studying interactions at the molecular, cell and tissue level, the native properties of the immobilized molecule, i.e. its biofunctionality, need to be retained upon immobilization. Here, the GAGs hyaluronan (HA) and chondroitin sulfate (CS), and synthetically sulfated derivatives of the two, were immobilized using biotin-streptavidin binding. The degree of biotinylation and the placement of biotin groups (end-on/side-on) were varied. The introduction of biotin groups could have unwanted effects on the studied molecule, but this aspect that is not always straightforward to evaluate. Hyaluronidase, an enzyme that degrades HA and CS in the ECM, was investigated as a probe to evaluate the biofunctionality of the immobilized GAGs, using both quartz crystal microbalance and high-performance liquid chromatography. Our results showed that end-on biotinylated HA was efficiently degraded by hyaluronidase, whereas already a low degree of side-on biotinylation destroyed the degrading ability of the enzyme. Synthetically introduced sulfate groups also had this effect. Hence hyaluronidase degradation is a cheap and easy way to investigate how molecular function is influenced by the introduced functional groups. Binding experiments with the proteoglycan aggrecan emphasized the influence of protein size and surface orientation of the GAGs for in-depth studies of GAG behavior.     

不同引物标记物在显色法芯片检测结核分支杆菌利福平和异烟肼耐药基因中应用比较

目的比较不同标记物在显色法芯片检测结核分支杆菌利福平和异烟肼耐药基因中的影响。方法分别采用地高辛、荧光素和生物素标记引物,建立地高辛-抗地高辛、荧光素-抗荧光素和生物素-亲和素酶呈色法芯片检测结核分支杆菌利福平(RFP)和异烟肼(INH)耐药基因方法,同时用3种方法检测46株结核分支杆菌临床分离株、19种非结核分支杆菌标准株、9种非分支杆菌标准株和结核分支杆菌H37Rv标准株,并对3种方法的敏感性和重复性进行比较。结果经3种方法平行检测,46例结核分支杆菌临床分离株结果完全一致;19种非结核分支杆菌标准株、9种非分支杆菌标准株结果均为阴性,结核分支杆菌H37Rv标准株结果均为野生型;地高辛系统和荧光素系统敏感度为2.0×103拷贝/ml,生物素-亲和素系统敏感度为2.0×104拷贝/ml;3种方法均有良好的重复性。结论3种方法均具有良好的重复性和特异性,生物素系统敏感度略低于地高辛系统和荧光素系统。     

Biotinidase catalyzes debiotinylation of histones

Summary Background Posttranslational modifications of histones play important roles in processes such as regulation of gene expression and DNA repair. Recently, evidence has been provided that histones in human cells are modified by covalent attachment of biotin. Aim of the study To determine whether the reverse process (debiotinylation of histones) occurs in biological samples and whether debiotinylation is an enzyme-mediated process; and to characterize the enzyme that mediates debiotinylation of histones. Methods Plasma and lymphocytes from healthy adults and a biotinidase-deficient patient were used as sources of debiotinylating enzymes. Debiotinylation of histones by plasma and lymphocyte proteins was measured using a colorimetric 96-well plate assay. Results Histones were debiotinylated rapidly if incubated with human plasma or lysates of lymphocytes. The following observations are consistent with the hypothesis that debiotinylation is an enzyme-mediated process: (i) Hydrolysis was slower at 4 °C compared to 37 °C; (ii) debiotinylating activity was destroyed when biological samples were heated at 90 °C for 30 min preceding incubation with biotinylated histones; and (iii) rates of debiotinylation were pH dependent. Rates of histone debiotinylation were significantly decreased in biotinidase-deficient samples. Conclusion Debiotinylation of histones in human samples is an enzyme-mediated process that is at least partly catalyzed by biotinidase. Received: 27 September 2001, Accepted: 6 January 2002     

疑难病研究-生物素酶缺乏症

报道1例生物素酶缺乏症病例,探讨因生物素酶缺乏症所致的临床特征和诊治方法。3岁男童,因脱发、皮疹6月,进行性肢体无力3个月就诊。运用尿气相色谱质谱联用及干燥血液生物素酶活性测定进行筛查,诊断符合生物素酶缺乏症。经生物素补充治疗,患儿3d后全身情况逐渐好转,1个月后基本恢复正常。生物素酶缺乏症常导致严重皮肤与神经系统损害,早期诊断与治疗是挽救患儿生命的关键。     

Fluorescence in situ hybridization (FISH): Detection of biotin- and digoxigenin-labeled signals on chromosomes

Summary A laboratory protocol of fluorescence in situ hybridization (FISH) on the air-dry chromosome preparation is described. This protocol contains procedures for preparing solutions; probe-labelings with biotin and digoxigenin by means of nick translation, random priming, and polymerase chain reaction; probe-annealing; and signal detection. Uses of solutions are simplified; compositions of each solution are outlined; and, whenever possible, easily accessible materials and supplies are used so that the FISH technique can be applied by all cytogenetic laboratories. Annealed signals at 4–5 kb or over were detectable, and background signals, if any at all, were low. The slides processed for FISH can be used subsequently for conventional chromosome bandings. Therefore, the same slide can be used for both conventional and molecular karyotype studies.