用固定化大肠埃希氏菌基因工程菌株转化戊二酰基-7-氨基头孢烷酸为7-氨基头孢烷酸的研究

用乙酸纤维将ＧＬ－７－ＡＣＡ酰化酶基因工程菌大肠埃希氏菌Ａ５６／ｐＭＲＣＵ－３３４菌株固定化,酶反应的最适温度为５０℃,最适ｐＨ为８．０,与游离细胞一致;固定化细胞对温度和ｐＨ的稳定性比游离细胞提高。用薄板层析分析固定化细胞裂解ＧＬ－７－ＡＣＡ反应液中产物７－ＡＣＡ的含量以及ＧＬ－７－ＡＣＡ的残存量,在ｐＨ８．０．３７℃时ＧＬ－７－ＡＣＡ的转化率达９０％,产生７－ＡＣＡ的能力为１２．３４ｍｇ／（ｇ固定化细胞·ｈ）。使用２０批之后,ＧＬ－７－ＡＣＡ的转化率仍达６６％。     

Distal aneurysms of the unpaired ACA: embryologic and therapeutic aspects

Anatomical variants of the cerebral arteries in general are frequent and due to the complex ontogenesis of these structures. Although encountered in many mammals, a single anterior cerebral artery (ACA) trunk is an infrequent finding in humans with an incidence of 3–5%. This vessel, giving rise to the arteries of both frontal lobes, is subjected to high flow volumes and distal arterial aneurysms have repetitively been encountered, mostly however before the introduction of endovascular treatment strategies. We report on five patients with acute SAH and arterial aneurysms of an unpaired ACA, who underwent coil embolisation. In all cases endovascular treatment using detachable platinum coils resulted in an at least satisfactory degree of aneurysm obliteration without parent artery occlusion or embolic infarcts. All patients had clinical and angiographic follow-up with median follow-up time of 29 months during which no aneurysm regrowth was encountered. In spite of a small patient group our results suggest, that altered flow dynamics due to enlarged single intracranial vessels may predispose to aneurysm formation and that endovascular embolisation is an appropriate treatment option in distal aneurysms of an unpaired ACA.     

重组表达的着丝粒蛋白-B N-端抗原在抗着丝粒自身免疫病血清检测中的应用

目的 分析重组表达的CENP-B抗原对抗着丝粒自身免疫病血清的鉴定结果，探讨其作为临床诊断指标的可行性。方法 通过构建原核表达载体，在大肠杆菌中高效表达CENP-B-N端300个氨基酸的1段多肽；纯化包涵体，制备重组表达的CENP-B抗原，并利用ELISA、Western blot的方法对临床诊断为阳性的ACA血清进行鉴定。结果 重组表达的CENP-B N-端抗原对ACA血清的ELISA阳性检出率为99％，Western blot阳性检出准确率为97％。结论 重组表达的CENP-B抗原可以作为抗着丝粒自身免疫病血清临床诊断的1个指标。     

未成熟网织红细胞指数IRF与不良妊娠结局发生的相关性研究

目的：观察未成熟网织红细胞指数（ IRF）水平与各种不良妊娠结局发生的相关性以及IRF偏低者比率与TORCH阳性、心磷脂抗体（ ACA）阳性相关性，从而探讨将IRF指标用于早期预测妊娠不良结局发生的意义。方法采用XE-2100型流式细胞术自动计数成熟网织红百分比（ RET ）及其亚群。酶联免疫吸附法（ELISA）检测ACA，TORCH。结果先兆流产组、胚胎停育组、妊高症组与正常妊娠组差异非常显著（P＜0．01），胎盘提前老化组与正常妊娠组差异也有显著性（P＜0．05），而胎儿畸形组与正常妊娠组差异无统计学意义（P＞0．05）。不良妊娠组IRF偏低者比率与TORCH阳性和ACA阳性均有明显相关性（ P＜0．01），而正常妊娠组与正常对照组IRF偏低者比率与TORCH阳性和ACA阳性均无明显相关性（P＞0．05）。结论 IRF与除胎儿畸形外的不良妊娠结局有关，联合IRF与TORCH及ACA检测对不良妊娠结局的诊断和预后监测更有参考意义。     

The H/ACA RNP assembly factor SHQ1 functions as an RNA mimic

SHQ1 is an essential assembly factor for H/ACA ribonucleoproteins (RNPs) required for ribosome biogenesis, pre-mRNA splicing, and telomere maintenance. SHQ1 binds dyskerin/NAP57, the catalytic subunit of human H/ACA RNPs, and this interaction is modulated by mutations causing X-linked dyskeratosis congenita. We report the crystal structure of the C-terminal domain of yeast SHQ1, Shq1p, and its complex with yeast dyskerin/NAP57, Cbf5p, lacking its catalytic domain. The C-terminal domain of Shq1p interacts with the RNA-binding domain of Cbf5p and, through structural mimicry, uses the RNA-protein-binding sites to achieve a specific protein-protein interface. We propose that Shq1p operates as a Cbf5p chaperone during RNP assembly by acting as an RNA placeholder, thereby preventing Cbf5p from nonspecific RNA binding before association with an H/ACA RNA and the other core RNP proteins.     

Reconstitution and structural analysis of the yeast box H/ACA RNA-guided pseudouridine synthase

Box H/ACA ribonucleoprotein particles (RNPs) mediate pseudouridine synthesis, ribosome formation, and telomere maintenance. The structure of eukaryotic H/ACA RNPs remains poorly understood. We reconstituted functional Saccharomyces cerevisiae H/ACA RNPs with recombinant proteins Cbf5, Nop10, Gar1, and Nhp2 and a two-hairpin H/ACA RNA; determined the crystal structure of a Cbf5, Nop10, and Gar1 ternary complex at 1.9 Å resolution; and analyzed the structure–function relationship of the yeast complex. Although eukaryotic H/ACA RNAs have a conserved two-hairpin structure, isolated single-hairpin RNAs are also active in guiding pseudouridylation. Nhp2, unlike its archaeal counterpart, is largely dispensable for the activity, reflecting a functional adaptation of eukaryotic H/ACA RNPs to the variable RNA structure that Nhp2 binds. The N-terminal extension of Cbf5, a hot spot for dyskeratosis congenita mutation, forms an extra structural layer on the PUA domain. Gar1 is distinguished from the assembly factor Naf1 by containing a C-terminal extension that controls substrate turnover and the Gar1–Naf1 exchange during H/ACA RNP maturation. Our results reveal significant novel features of eukaryotic H/ACA RNPs.     

Metallothionein protein and minichromosome maintenance protein-2 expression in adrenocortical tumors

AimSome resected adrenal-confined adrenocortical carcinomas metastasize and others not. The present study was designed to evaluate the expression of metallothionein protein (MT) and minichromosome maintenance protein-2 (MCM2) in adrenocortical carcinomas and adrenocortical adenomas, and to test the correlation between this and adrenocortical carcinoma aggressiveness.Materials and methodsThe study comprised 14 patients operated on for adrenocortical carcinoma, 15 operated on for adrenocortical adenoma and 2 with normal adrenals. Hematoxylin-eosin staining was used for histological evaluation under light microscopy, and sequential sections were used for MCM2 and MT staining.ResultsIn normal adrenals, positive staining was weak for MT and zero for MCM2. Rates of positive staining for MT and MCM2 were significantly higher in adrenocortical carcinomas than in adrenocortical adenomas (P = 0.008 and P < 0.001, respectively). In adrenocortical carcinomas, a significant positive correlation was found between MCM2 staining and Weiss revisited score (P = 0.022) but not for Weiss score, and a significant positive correlation was found between MCM2 and mitotic rate on histology (P = 0.033). MCM2 but not MT staining was also shown to correlate significantly with stage IV carcinoma (P = 0.008 and P = 0.165, respectively).ConclusionMCM2 and MT are overexpressed in adrenocortical carcinoma, and MCM2 expression correlates significantly with metastatic disease.     

Superficial vascular anatomy of the medial prefrontal cortex: an anatomical study

Background

Superficial vascular anatomy of the medial prefrontal cortex, which is exposed after craniotomy for the anterior interhemispheric approach, has received little attention in the anatomy literature. This study focuses on the precise vascular anatomy of the medial part of the prefrontal cortex and provides more detailed information for surgery.

Methods

Five adult cadaveric heads were used in this study. After a bifrontal craniotomy, the dura was opened and the superficial vascular structures of the medial prefrontal cortex were exposed in 10 hemispheres. The CS was used as a landmark, and the location and the course of the medial cortical vessels were recorded. The variations were noted and photographed.

Results

There are 4 major superficial veins and 3 arteries on the medial prefrontal cortex, which are important during the surgery. Anterior frontal vein, MFV, PFV, and frontopolar veins drain the superficial part of the medial prefrontal cortex to the SSS. The frontomarginal artery and cortical branches of the frontopolar and callosomarginal arteries supply this region. One great BV on each hemisphere poses risk during the opening of the dura of the prefrontal cortex. All of the veins drain to the SSS.

Conclusions

The surface of the medial prefrontal cortex has a rich and complex vascular network and represents the first obstacle for surgery. The upper part of the medial prefrontal cortex seems safer than the lower part; the CS is a reliable and crucial landmark in planning and performing surgery in this region.