PET-CT在非完全实性肺结节中的应用价值

肺癌在中国恶性肿瘤的发病率位居第一,随着低剂量薄层CT在肺癌筛查中的广泛应用,临床发现更多表现为非完全实性结节的肺腺癌,目前众多研究使CT影像学特征和肺腺癌病理的关系得到更进一步的认知,虽然CT能对部分非完全实性结节做出定性和定位诊断,但仍有部分非完全实性结节诊断困难,PET-CT结合了病灶的代谢信息和精确的定位信息,从而提高对肺部结节诊断的敏感性、特异性、准确性,综合多个文献PET-CT在非完全实性结节中的诊断分期价值较CT无明显提升,却在评估预后和制定合适手术方案上可以起到一定的作用,本文就PET-CT在SSN中的应用价值进行阐述。     

Purification and characterization of RNA polymerase I from a higher plant.

RNA polymerase I was purified from chromatin isolated from auxin-treated soybean hypocotyl. Purification was achieved by using Agarose A-1.5m gel filtration, DEAE-cellulose, CM-sephadex, and phosphocellulose chromatography, and sucrose density gradient centrifugation. With denatured calf thymus DNA as template, the enzyme has a high specific activity (200-300 nmol/mg/30 min at 28 degrees C) which is comparable to other RNA polymerase I enzymes purified from animals and yeast. While the gel profiles indicate that purification to homogeneity (greater than 90%) may not have been achieved, the enzyme appears to be composed of possibly 7 subunits, several of which are similar to the subunits of yeast RNA polymerase I. The putative subunits and molar ratios are 183 000 (1), 136 000 (1), 50 000 (0.5), 46 000 (0.5), 40 000 (0.5), 33 000 (0.2), and 28 000 (2). The purified enzyme strongly prefers a completely denatured template such as poly(dC).     

Characterization and sequence analysis of a developmentally regulated putative cell wall protein gene isolated from soybean

A cDNA clone, pTU04, which hybridizes to two different sizes of mRNA on Northern blots was isolated from soybean suspension culture cell poly(A) RNA. Northern analysis reveals that meristematic tissue produces a 1050-nucleotide mRNA while quiescent mature cells produce primarily a 1220-nucleotide mRNA homologous to pTU04. The cDNA and its corresponding genomic clone have been partially characterized. The nucleotide sequence of the gene predicts a proline-rich protein, designated SbPRP1, which contains a signal peptide sequence and 43 repeats of a sequence consisting primarily of Pro-Pro-Val-Tyr-Lys (CCA-CCA-GTT-TAC-AAG). From nuclease S1 and hybrid-select translation analyses, the cDNA clone pTU04 appears to represent the mRNA for the mature tissue 1220-nucleotide RNA observed on Northern blots. Although there is no direct proof that the encoded protein is a cell wall protein, it has the properties similar to previously isolated cell wall proteins: 1) it is very basic with a high content of Pro, Tyr, and Lys; 2) it has similar hydropathic properties; and 3) its repeating unit shares sequence homology with that of more highly characterized cell wall proteins, generally termed extensin (Chen, J., and Varner, J. E. (1985) EMBO J. 4, 2145-2151; Smith, J. J., Muldoon, E. P., Willard, J. J., and Lamport, D. T. A. (1986) Phytochemistry 25, 1021-1030.     

ATPase activity in plasmalemma-rich vesicles isolated by aqueous two-phase partitioning from Vicia faba mesophyll and epidermis: Characterization and influence of abscisic acid and fusicoccin

Plasmalemma-rich microsomal vesicles were prepared from whole leaf and acid-washed epidermal tissue of Vicia faba L. cv. Osnabrücker Markt by aqueous two-phase partitioning in dextran T-500 and polyethylenglycol 1350 aqueous phases. These vesicles were tightly sealed and predominantly right-side out, and contained a K⁺ -stimulated, mg²⁺-dependent and vanadate-sensitive ATPase. The enzyme from both tissues exhibited nearly identical properties: pH optimum 6.4, K_m for ATP 0.60 mM(whole leaf) and 0.67 mM (epidermis). V_max -480 nmol (mg protein)¹ min¹ (whole leaf) and 510 nmol (mg protein)¹ min¹ (epidermis), I₅₀ (Na₃,VO₄) 7.5 μM (whole leaf) and 15 μM (epidermis). The enzyme was not inhibited by NO₃(50 mM)or sodium azide (I mM). DCCD (20 μM) reduced enzyme activity to 50% (whole leaf) and 58% (epidermis), gramicidin S (20 μM) to 36% (whole leaf) and 41%(epidermis). Ca²⁺ inhibited the ATPase [I₅₀, C²⁺: 0.5 mM(whole leaf) and 0.8 mM(epidermis)]. Ca²⁺ inhibited the ATPase [I₅₀, C²⁺ 0.5 mM(whole leaf) und 0.8 (epidermis)]. The vanadate-sensitive ATPase from whole leaf and epidermal tissue was slightly but significantly stimulated by fusicoccin (FC) at a concentration (0.13 μM) promoting stomatal opening. The stimulation was not seen in the solubilized ATPase. Stomata of the cultivar used here were insensitive lo (±)ABA up to 2 μM level which is effective in most other cultivars and species. Likewise, at this concentration no effect of ABA on the activity of the epidermal ATPase was observed. The data are discussed with respect to the interaction of FC and ABA with the ATPase.     

烟青虫感染核型多角体病毒后围食膜的病变

昆虫的围食膜是衬在昆虫中肠内一种网状的结构,它可充作虫体抵御外来病原侵染的一道屏障。关于鳞翅目昆虫幼虫感染了昆虫病毒后围食膜的病变问题,国内外鲜有报道。尤锡镇和康慧娟(1985)曾以实验证明家蚕围食膜对核型多角体病毒有灭活作用,而且认为核型多角体病毒不能侵染和破坏围食膜。Derksen和Granados(1988)则证明染病幼虫的围食膜因不同杆状病毒(包括两种核型多角体病     

Fractionation of nucleoli from auxin-treated soybean hypocotyl into nucleolar chromatin and preribosomal particles

Nucleoli from auxin-treated tissues (Glycine max L. var Wayne or Kaoshiung No. 3) were isolated and purified by Percoll density gradient centrifugation. There was a 2.1-fold increase in RNA and a 2.8-fold increase in protein after a 24-h auxin treatment per unit nucleolar DNA. More than 150 acid-soluble protein spots were associated with the auxin-treated nucleoli on two dimensional (2-D) gel electropherograms.

Nucleoli from auxin-treated tissue were fractionated by suspension in 20 millimolar dithiothreitol at room temperature for 20 minutes into two distinct fractions referred to as the nucleolar chromatin and preribosomal particle fractions. The DNA:RNA:protein ratio of the chromatin fraction was 1:2.5:14. Most of RNA polymerase 1 activity and nucleolar DNA recovered in this fraction. The acid-soluble proteins in the chromatin were resolved into 32 protein spots on 2-D gel electropherogram. The most abundant spots were identified as histones.

The nucleolar preribosomal particle fraction had a DNA:RNA:protein ratio of 1:24:102 and contained only trace amounts of RNA polymerase 1 activity and only 10 per cent of the nucleolar DNA. Acid-soluble proteins associated with these particles were resolved into 78 protein spots; 72 of these (acid-soluble) protein spots corresponded in 2-D gel electrophoresis to 80S cytoplasmic ribosomal proteins. Some 15 protein spots found in 80S ribosomal proteins were absent in the preribosomal particles. It seems reasonable, based on these data, that the enlargement of nucleoli after auxin treatment is primarily due to the large increase in ribosomal proteins and rRNA which accumulate and assemble in the nucleoli in the form of preribosomal particles.