放射治疗对鼻咽癌患者细胞免疫功能的影响

应用抗人淋巴细胞单克隆抗体检测３２例鼻咽癌患者放疗前、后外周血Ｔ淋巴细胞亚群,并与１２例非癌人群（对照组）进行对比。结果：鼻咽癌患者ＯＫＴ３、ＯＫＴ４及ＯＫＴ４／ＯＫＴ８值与对照组相比明显降低,ＯＫＴ８显著上升（Ｐ＜０．０５）;放疗后ＯＫＴ３、ＯＫＴ４及ＯＫＴ４／ＯＫＴ８值进一步下降,ＯＫＴ８进一步升高（Ｐ＜０．０１）。提示鼻咽癌患者细胞免疫功能低下,放射治疗可进一步抑制鼻咽癌患者的细胞免疫功能。     

Structural evolution of wheat chromosomes 4A, 5A,and 7B and its impact on recombination

The construction of comparative genetic maps of chromosomes 4A^m and 5A^m of Triticum monococcum and chromosomes of homoeologous groups 4, 5 and 7 of T. aestivum has provided insight into the evolution of these chromosomes. The structures of chromosomes 4A, 5A and 7B of modern-day hexaploid bread wheat can be explained by a 4AL/5AL translocation that occurred at the diploid level and is present both in T. monococcum and T. aestivum. Three further rearrangements, a 4AL/7BS translocation, a pericentric inversion and a paracentric inversion, have taken place in the tetraploid progenitor of hexaploid wheat. These structural rearrangements and the evolution of chromosomes 4A, 5A and 7B of bread wheat are discussed. The presence of the 4AL/5AL translocation in several Triticeae genomes raises two questions — which state is the more primitive, and is the translocation of mono- or poly-phylogenetic origin? The rearrangements that have occurred in chromosome 4A resulted in segments of both arms having different positions relative to the telomere, compared to 4A^m and to 4B and 4D. Comparisons of map length in these regions indicate that genetic length is a function of distance from the telomere, with the distal regions showing the highest recombination.     

Magnetic resonance imaging in vivo monitoring of T2 relaxation time: Quantitative assessment of primate brain maturation

This work describes quantitative MRI assessment of primate brain maturation. Nine young baboons were followed from the age of one to 30 months. Assessment of myelination was based on the gray/white matter contrast on MR images and the evolution of T2 relaxation time respectively. The brain maturation began in the posterior fossa and progressed to the olfactory bulbs corresponding to decreasing white matter T2 values. Relaxation parameters provide new opportunities to trace the myelination process in vivo.     

创伤后巨噬细胞对T细胞白介素2及白介素2受体α基因表达的直接接触抑制作用

以25μg/ml的丝裂霉素C处理巨噬细胞30min,可阻断巨噬细胞白介素1(IL-1)、白介素6(IL-6)、肿瘤坏死因子(TNF)及前列腺素E_2(PGE_2)的合成与分泌。创伤小鼠巨噬细胞经丝裂霉素C处理后,可明显抑制正常T细胞白介素2(IL-2)mRNA及IL-2受体(IL-2R)αmRNA水平,并增强Ts细胞的抑制活性。去除T细胞中Ts细胞可使巨噬细胞的抑制作用消失。表明创伤后巨噬细胞可通过直接的细胞接触方式抑制T细胞IL-2及IL-2 Rα的基因表达,且这一作用是通过增加Ts细胞活性而实现的。     

Oral administration of antigen does not influence the proliferation and IFN-γ production of responsive CD8+ T cells but enables to establish T cell clones with different lymphokine production profile.

Feeding of a whole casein diet, which abolished the α_s1-casein-specific proliferation and IFN-γ productivity of CD⁴⁺ T cells, did not affect the proliferative response of CD8⁺ T cells with regard to the antigen dose response, cell dose response, kinetics of the proliferation and epitope specificity, as well as IFN-γ production. To assess the characteristics of the CD8⁺ T cells, we established α_s1-casein-specific CD8⁺ T cell clones from both casein-fed and control mice. The established clones produced different amount of IFN-γ and IL-10, and one clone derived from the casein-fed mice produced a remarkable amount of IL-10. The clones from casein-fed mice produced considerable amounts of TGF-β, while those from control mice produced only small amounts. The possible role of CD8⁺ T cells in oral tolerance is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Alteration of T4 lysozyme structure by second-site reversion of deleterious mutations.

Mutations that suppress the defects introduced into T4 lysozyme by single amino acid substitutions were isolated and characterized. Among 53 primary sites surveyed, 8 yielded second-site revertants; a total of 18 different mutants were obtained. Most of the restorative mutations exerted global effects, generally increasing lysozyme function in a number of primary mutant contexts. Six of them were more specific, suppressing only certain specific deleterious primary substitutions, or diminishing the function of lysozymes bearing otherwise nondeleterious primary substitutions. Some variants of proteins bearing primary substitutions at the positions of Asp 20 and Ala 98 are inferred to have significantly altered structures.     

中国桑寄生科植物资料(三)

作者在编著《ＦｌｏｒａｏｆＣｈｉｎａ》Ｌｏｒａｎｔｈａｃｅａｅ过程中,据近年采集的标本和花粉形态研究,修订了《中国植物志》第２４卷的桑寄生科。现报道钝果寄生属（Ｔａｘｉｌｕｓ）二个新分类单位：油杉钝果寄生Ｔ．ｒｅｎｉ,狭叶钝果寄生Ｔ．ｌｉｑｕｉｄａｍｂａｒｉｃｏｌｕｓｖａｒ．ｎｅｒｉｆｏｌｉｕｓ的描述和枫香钝果寄生Ｔ．ｌｉｑｕｉｄａｍｂａｒｉｃｏｌｕｓｖａｒ．ｌｉｑｕｉｄａｍｂａｒｉｃｏｌｕｓ及显脉钝果寄生Ｔ．ｃａｌｏｒｅａｓｖａｒ．ｆａｒｇｅｓｉ的地理分布区等;另有梨果寄生属（Ｓｃｕｒｒｕｌａ）一个新组合：藏南梨果寄生Ｓ．ｂｕｄｄｌｅｉｏｉｄｅｓｖａｒ．ｈｅｙｎｅｉ。     

Evolution of the Mitochondrial Cytochrome Oxidase II Gene in Collembola

The sequence of the mitochondrial COII gene has been widely used to estimate phylogenetic relationships at different taxomonic levels across insects. We investigated the molecular evolution of the COII gene and its usefulness for reconstructing phylogenetic relationships within and among four collembolan families. The collembolan COII gene showed the lowest A + T content of all insects so far examined, confirming that the well-known A + T bias in insect mitochondrial genes tends to increase from the basal to apical orders. Fifty-seven percent of all nucleotide positions were variable and most of the third codon positions appeared free to vary. Values of genetic distance between congeneric species and between families were remarkably high; in some cases the latter were higher than divergence values between other orders of insects. The remarkably high divergence levels observed here provide evidence that collembolan taxa are quite old; divergence levels among collembolan families equaled or exceeded divergences among pterygote insect orders. Once the saturated third-codon positions (which violated stationarity of base frequencies) were removed, the COII sequences contained phylogenetic information, but the extent of that information was overestimated by parsimony methods relative to likelihood methods. In the phylogenetic analysis, consistent statistical support was obtained for the monophyly of all four genera examined, but relationships among genera/families were not well supported. Within the genus Orchesella, relationships were well resolved and agreed with allozyme data. Within the genus Isotomurus, although three pairs of populations were consistently identified, these appeared to have arisen in a burst of evolution from an earlier ancestor. Isotomurus italicus always appeared as basal and I. palustris appeared to harbor a cryptic species, corroborating allozyme data. Received: 12 January 1996 / Accepted: 10 August 1996