Relative carriage rates of nuclear dehydrogenating clostridia in two populations of different colorectal cancer risk

Carriage of nuclear dehydrogenating clostridia has been associated with colon cancer and implicated in its aetiology. This study has compared the carriage of these organisms in a British population at high risk for the development of colon cancer with a low risk Nigerian population. Clostridia were found in all of the stools from both populations. Nuclear dehydrogenating clostridia were only found in the stools of the British subjects (32%). These results support the suggestion that the carriage rate of nuclear dehydrogenating clostridia in a population is related to the risk of colon cancer.     

牵张延长下颌骨对二腹肌纤维型构成影响的研究

目的 :研究牵张延长下颌骨前后二腹肌的组织化学特征。方法 :应用肌球蛋白ATP酶 (pH9.4)染色法 ,观测了牵张前后 8只狗的二腹肌肌纤维类型 ,并用VIDAS图像分析仪测量其横截面积。结果 :ATP酶染色 ,二腹肌肌纤维分为Ⅰ型和Ⅱ型 ,Ⅰ型纤维数量较Ⅱ型纤维少。牵张延长下颌骨后 ,Ⅰ型纤维数量显著性增多 ,Ⅱ型纤维数量显著性减少。牵张成骨后 ,Ⅰ型纤维、、Ⅱ型纤维的横截面积与术前比较没有显著性差异。结论 :牵张延长下颌骨后 ,与牵张方向平行的二腹肌肌纤维型分布发生了与功能变化相适应的改变     

Polymorphism of the ABO blood group genes in Han, Kazak and Uygur populations in the Silk Route of northwestern China

Genetic polymorphism in the ABO blood group gene of Han, Kazak and Uygur populations inhabiting the most northwestern part of China was investigated using polymerase chain reaction-based techniques. The present study enrolled 43 healthy unrelated Han, 37 Kazak and 59 Uygur volunteers. The allele in A1 blood group is distinguished A0101 and A0102 in difference of nucleotide position 467. The A0101 allele is more frequent in Caucasian and the A0102 allele is characteristic in Mongoloid. It must be notable that A0201 in the A2 group (with a single base deletion at nucleotides 1059 to 1061) which was characteristic of Caucasian was observed in Kazak and Uygur populations but not in Han. Further, 00201 (with no nucleotide deletion at 261 and three nucleotide differences), which is frequent in different races including Caucasian except for Mongoloid, was detected also in Kazak and Uygur populations. The frequencies of B0101 in Kazak, Uygur and Han were comparable to those of other Asian populations but higher than those of Caucasian populations. Collectively, these results reveal that the allele frequencies of Kazak and Uygur at the ABO blood group locus are an intermediate between those of Mongoloid and Caucasian, suggesting the admixed feature of Kazak and Uygur with Mongoloid and Caucasian.     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.      

肝尾状叶的外科解剖及其临床应用

在42例成人肝脏标本上，研究了肝尾状叶的形态，动脉、静脉和肝管的分布特征；尾状叶常有3个突起，即尾状突、乳头突和下腔静脉后突，且变异较大；尾状叶有两个恒定的蒂，其结构排列由浅入深分别是门静脉支、肝动脉支和肝管。尾状叶静脉有2～5支，其中以3支居多，主要汇入下腔静脉肝后段的中、下1／3部的左前壁。中结合解剖学研究总结了施行肝尾状叶肿瘤切除术的方法和经验。     

pcDNA3.1/hIL-18真核表达载体的构建及表达

目的 :构建重组真核表达质粒pcDNA3.1/IL 18,并在哺乳动物细胞COS 7和Rlc310中进行瞬时和稳定性表达。方法 :从含hIL 18基因的中介载体 pGEM TEasy( pGEM T/hIL 18)中 ,以限制性内切酶酶切方法获得目的片段 ,克隆入真核表达质粒 pcDNA3.1( )中。以脂质体法转染COS 7和Rlc310细胞 ,用RT PCR检测IL 18mRNA的水平 ,免疫组化染色法检测蛋白表达。结果 :构建了hIL 18基因的重组真核表达质粒pcDNA3.1/IL 18,并可在哺乳动物细胞中瞬时、稳定表达 ,获得了可稳定表达hIL 18基因的Rlc310细胞株。结论 :pcDNA3.1/IL 18的构建及表达 ,为IL 18抗肿瘤作用的研究奠定了基础     

心钠素免疫反应在豚鼠耳蜗中的整体分布

目的 :研究豚鼠耳蜗中心钠素 (ANP)免疫反应的分布状态 ,为探讨ANP在耳蜗中的作用提供形态学基础。方法 :采用免疫组织化学ABC法检测ANP在正常豚鼠耳蜗各组织中的分布特征。结果 :在耳蜗 1～ 4回的血管纹、螺旋缘、Corti’s器、螺旋神经节和中间阶外壁的螺旋韧带均发现有ANP反应 (ANP IR)阳性产物 ;而耳蜗骨壁、前庭膜、鼓阶外壁的螺旋韧带和鼓阶的下壁ANP IR为阴性。结论 :耳蜗中的ANP在内耳淋巴液的生成和声信号的传导以及耳蜗血流量的调节等方面可能担负着重要的作用