Cytoplasm-to-myonucleus ratios in plantaris and soleus muscle fibres following hindlimb suspension

Summary In multinucleated skeletal muscle fibres the size of the cytoplasmic volume-to-myonucleus ratio is related to the myosin heavy chain phenotype, with the ratio being larger in those fibres expressing the fast myosin heavy chain phenotype. It is unknown, however, whether this ratio is modulated during muscle fibre adaptation, such as that which occurs following muscle unloading. In this study the relationship between cross sectional area, myonuclear number and myosin type, in single fibres from the plantaris and soleus muscles of adult rats following 28 days of hindlimb suspension was examined. Each fibre was cut transversely into two segments; one segment was used for immunohistochemical identification of myosin type, the other for determination of cross sectional area and myonuclei number. Single fibre analysis revealed significant atrophy of both plantaris fast and soleus slow fibres; the mean cross sectional area (m²) of these fibres, 3104±183 and 2082±107 (mean ±se), being 70 and 45%, respectively, of control means. The decreases in cross sectional area were not accompained by corresponding decreases in the number of myonuclei (myonuclei/mm); in plantaris fast fibres the mean myonuclei counts were within the control range (88±8 (hindlimb suspension), 76±7 (control)), in soleus slow fibres the counts were significantly increased (185±12 (hindlimb suspension), 154±11 (control)). The changes resulted in a significant decrease in the cytoplasmic volume-to-myonucleus ratio (m³×10³) for both fibre types; the mean ratios of 39±3 and 12±1, were 60% and 36% of control means for the plantaris fast and soleus slow fibres, respectively. These results indicate that following hindlimb suspension atrophy of muscle fibres the myonuclei numbers remain constant or increase and, hence, the effective cytoplasmic-to-myonucleus ratio is decreased. Further, the described changes are significantly greater in soleus slow than plantaris fast fibres.     

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.      

三氧化二砷对皮肤成纤维细胞、中性粒细胞MMPs活性,TIMP-1及TGF-β1表达的影响

目的：砒石是化腐生肌的常用中药，其主要成分是三氧化二砷（As₂O₃）。本研究通过观察As₂O₃对基质金属蛋白酶（MMPs）活性、基质金属蛋白酶组织抑制因子-1（TIMP-1）及转化生长因子β₁（TGF-β₁）表达影响，探讨化腐中药能否调节胶原代谢，从而治疗慢性皮肤溃疡。方法:明胶酶谱法检测大鼠中性粒细胞（PMNs）来源的MMP-9活性、人成纤维细胞（hFb）分泌的MMP-1、MMP-2的活性，免疫细胞化学法检测hFb TIMP-1、TGF-β₁的表达。结果:As₂O₃浓度在50 mg/L时可以提高大鼠PMNs来源的MMP-9的活性（P<0.01）；在0.8 mg/L可以提高hFb分泌的MMP-1、MMP-2的活性（分别P<0.01）；同时As₂O₃作用于hFb 6 h、12 h、18 h后，TIMP-1、TGF-β₁表达持续降低（P<0.01）。结论:As₂O₃在一定范围内可提高PMNs来源的MMP-9的活性；也可提高hFb分泌的MMP-1、MMP-2的活性，同时抑制hFbTIMP-1、TGF-β₁的表达。提示砷类制剂可通过提高多种MMPs的活性，降低TIMP-1的表达从而发挥化腐作用。     

Techniques of exposure for the stiff total knee

Primary and revision total knee arthroplasty have become common orthopaedic procedures. The operating surgeon, at times, may be faced with a difficult surgical case due to soft tissue contractures or bone deformities. A review of multiple surgical techniques using soft tissue releases and osteotomies are presented including their potential complications. Although these techniques are aimed at the atypical operative case, the operating surgeon may utilize them for ‘routine’ exposures as well. Importance is focused on the functional integrity of the knee extensor mechanism.     

应用四环素调控系统建立可调控抗恶性疟原虫DNA疫苗的初步研究

目的 :应用四环素 (tetracycline,Tet)可调控系统建立可调控的抗恶性疟原虫的DNA疫苗。方法 :首先构建恶性疟原虫顶端膜抗原 1(AMA 1)基因和转录激活因子 (tTA或rtTA)基因的真核表达质粒pTL 8/AMA 1和pTL 8/AMA 1(rtTA) ,并大量制备这两种质粒及表达转录抑制子 (tTS)的质粒pUHS6 1。以pTL 8/AMA 1、pTL 8/AMA 1(rtTA)和pTL 8/AMA 1(rtTA)加pUHS6 1/tTS免疫小鼠后 ,用四环素类似物强力霉素 (doxcycline ,dox)诱导或抑制上述DNA载体内AMA 1的表达 ,并分离小鼠血清检测针对AMA 1抗体的表达情况。结果 :①构建了真核表达质粒pTL 8/AMA 1和pTL 8/AMA 1(rtTA) ;②pTL 8/AMA 1和pTL 8/AMA 1(rtTA)在没有被诱导表达时 (仅基础表达 ) ,可诱导明显的免疫应答。在以pTL 8/AMA 1(rtTA)与含tTS的pUHS6 1共同免疫后 ,可极大地降低其免疫应答。应用dox诱导pTL 8/AMA 1(rtTA)中的AMA 1基因表达后 ,可明显引起免疫应答。结论 :pTL 8/AMA 1(rtTA)附加pUHS6 1构成了可调节的DNA免疫系统。该系统的建立将对进一步深入研究DNA疫苗的免疫机制和调控基因表达 ,减少不良免疫反应以及进行可精确调控的基因治疗打下一定的基础     

右旋糖酐40、70对红细胞与内皮细胞粘附的影响

采用流室显微观察系统，定量研究右旋糖酐４０（ＤＸ４０）和右旋糖酐７０（ＤＸ７０）对红细胞与内皮细胞动态粘附特性的影响。统计分析处理数据，得到反映切应力与细胞间动态粘附数关系的经验公式及粘附特征常数ａ，ｂ值。ａ值反映红细胞的初始粘附数，ｂ值反映随切应力增大，粘附数减小的速率。ＤＸ７０实验组的ａ值大于ＤＸ４０组的，而ｂ值的情况相反。故结果显示切应力越大，粘附的红细胞越少；ＤＸ４０使红细胞的粘附明显减少；ＤＸ７０使红细胞粘附显著增加。由此提示不同长度的细胞桥接分子对红细胞的粘附影响不同，且临床上选用ＤＸ４０作血浆扩容剂较ＤＸ７０优越得多     

Studies on the origin of redox enzymes in seminal plasma and their relationship with results of in-vitro fertilization

Glutathione (GSH), GSH peroxidase (GPX), GSH reductase (GRD), superoxide dismutase (SOD) and catalase-like enzyme activity were quantified in seminal plasma from normozoospermic patients, men with known distal ductal occlusion, proven fathers and male partners of couples receiving in-vitro fertilization (IVF) treatment for both male and female causes. Glutathione was non-detectable (< 2.5 microM) in seminal plasma. None of the enzyme activities per unit volume were lower in semen from vasectomized men, suggesting that they did not originate substantially from the testis or epididymis. The strongest relationships between enzyme activities and accessory gland markers were between zinc and GRD (r = 0.678), SOD (r = 0.602) and GPX (r = 0.548), suggesting a largely prostatic origin of these enzymes. Only weak relationships between accessory gland markers and catalase-like activity suggested a multi-glandular source of this enzyme. There was no relationship between the activity of any of the enzymes in the IVF patients with their fertilization rates in vitro or the establishment of pregnancy after IVF. Nor was there any correlation of enzyme activity with the morphology and percentage of motile spermatozoa in semen or with the percentage motility of spermatozoa immediately after swim-up or after overnight incubation. These findings suggest that the protective enzymes in the seminal plasma are contributed largely by the prostate and little by the epididymis, and that in most cases of IVF, they have no major influence on the outcome.      

The mouse Mid1 gene: implications for the pathogenesis of Opitz syndrome and the evolution of the mammalian pseudoautosomal region

We have recently reported isolation of the gene responsible for X- linked Opitz G/BBB syndrome, a defect of midline development. MID1 is located on the distal short arm of the human X chromosome (Xp22. 3) and encodes a novel member of the B box family of zinc finger proteins. We have now cloned the murine homolog of MID1 and performed preliminary expression studies during development. Mid1 expression in undifferentiated cells in the central nervous, gastrointestinal and urogenital systems suggests that abnormal cell proliferation may underlie the defect in midline development characteristic of Opitz syndrome. We have also found that Mid1 is located within the mouse pseudoautosomal region (PAR) in Mus musculus , while it seems to be X- specific in Mus spretus. Therefore, Mid1 is likely to be a recent acquisition of the M. musculus PAR. Genetic and FISH analyses also demonstrated a high frequency of unequal crossovers in the murine PAR, creating spontaneous deletion/duplication events involving Mid1. These data provide evidence for the first time that genetic instability of the PAR may affect functionally important genes. In addition, we show that MID1 is the first example of a gene subject to X-inactivation in man while escaping it in mouse. These data contribute to a better understanding of the molecular content and evolution of the rodent PAR.      

Expression of blood group antigens including HLA markers in human adult liver

The localisation of the principal blood group antigens has been studied in human liver. These blood group antigens included the erythrocyte antigens and the antigen of the major histocompatibility complex. This study was performed by the indirect immunofluorescence technique using polyclonal antibodies of human or animal origin and monoclonal antibodies from hybridomas. This study has shown that the normal hepatocyte is lacking in blood group antigens. On the contrary, the biliary cell was rich in antigenic markers: the main antigens expressed were Lewis, Pr, HLA-A and B antigens. In Kupffer cells, only i and HLA-DR antigens were clearly expressed. The endothelial cells of blood vessels mainly show A, B, H, HLA-A and B antigens; HLA-DR and Pr are slightly expressed. HLA-DR antigens were more strongly expressed on veins than on arteries. Dendritic cells have been identified in the portal space of human liver. They bore i and HLA-DR antigens.