MR 弥散加权成像对鉴别诊断良恶性椎体压缩性骨折的临床价值研究

目的：探讨MR弥散加权成像(DWI)鉴别诊断良恶性椎体压缩性骨折的临床价值。方法：对57 例经临床或病理证实的椎体 良恶性压缩性骨折患者行矢状位T1WI、T2WI、T2WI/FS 及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR 序列 和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数(ADC)值,并进行统计学分析。结果：(1)MR 常规序列和 DWI序列(b=500s/mm2)表现：良性椎体压缩性骨折呈长T1 长或等T2 改变,T2WI/FS 呈高信号,DWI 可以呈高信号、等信号及低 信号;恶性椎体压缩性骨折呈长T1 长T2 信号,大部分病灶T2WI/FS 及DWI呈高信号,少数变现为低信号;(2)MR 常规序列和 DWI 序列(b=500s/mm2)病灶检出率的比较：T1WI、T2WI/FS 及DWI序列病灶检出率均高于T2WI 序列,其间的差别有显著性意 义(P<0.01),T1WI、T2WI/FS 及DWI序列病灶检出率之间无显著性差异(P>0.01);(3)ADC 值比较：在DWI(b=500 s/mm2)上,良性组 ADC 值为(2.03± 0.83)× 10-3mm2/s,恶性组ADC 值为(1.37 ± 0.75)× 10-3mm2/s,正常组ADC值为(0.36± 0.21)× 10-3mm2/s,成像条 件相同时,良性组高于恶性组,两组间有明显的统计学意义(P<0.05)。结论：DWI可较好的反映椎体的弥散特征,ADC值作为量化 指标可对良恶性椎体压缩性骨折进行可靠鉴别。     

Genetic segregation of microsatellite markers in Saccharum officinarum and S. spontaneum

Genetic mapping techniques can be used to study the interaction between two different genomes after hybridization. This study investigated a Saccharum officinarum (Green German or GG, 2n approximately 11x approximately 110) x S. spontaneum (IND 81-146 or IND, 2n approximately 7x approximately 56) interspecific cross. Segregation of 193 microsatellite (SSR) loci was evaluated in the F(1) progeny of 169 full-sibs of the cross. Following the two-way pseudo-testcross strategy and 'cross pollination' population type, linkage groups (LG) and phases were established for each parent map, using the criteria of LOD score > or = 3.0 and a maximum recombination frequency of 0.35. Of the 193 markers analyzed, 61 were IND-specific, 106 were GG-specific, and 26 were heterozygous in both parents. About 78% of the markers segregated in a Mendelian fashion and 22% were distorted (as evaluated by chi(2)-tests, P < or = 0.01). The GG map included 91 marker loci arranged into 25 LG covering 1180 cM of the officinarum genome. The IND map consisted of 46 marker loci assembled into 10 LG, which spanned 614 cM of the spontaneum genome. A specific chromosome associated with segregation distortion was detected in the female (GG) genome only, probably as a result of double reduction. The segregation patterns of the marker loci indicated a centromere-driven distortion process with the shared allelic markers (as putative centromeres) regulating the placement and association of markers with opposite phase (coupling vs repulsion) and dosage on either side. Although incomplete, the framework maps were informative with respect to segregation distortion, chromosome fusion, rearrangements, and translocations, observed in both parental genomes as a result of their merger.     

新疆甘草化学成分研究

从新疆甘草(GlycyrrhizauralensisFisch.)根中分离得到5个化合物,分别鉴定为:槲皮素(1)、甘草次酸(2)、阿魏酸(3)、5,7,3′,4′-四羟基-7-葡萄糖基二氢黄酮醇(4)、8,5′-二羟基3′α-鼠李糖黄酮(5)。其中化合物4,5为首次从该植物中分离得到。     

高血压脑出血患者术后重症监护治疗与早期再出血的相关因素分析

目的:探究高血压脑出血患者术后重症监护治疗与早期(24 h内)再出血的相关因素。方法:回顾性分析2014年1月至2018年10月于中山大学附属第一医院及中山市人民医院行手术治疗并进行重症监护的高血压脑出血患者的相关资料,记录术后早期发生再出血情况,比较其相关因素,包括年龄、性别、术前格拉斯哥昏迷量表(GCS)评分、出血量、术前收缩压、术后收缩压、镇静时间、插管时间、有无使用止血药、血压波动、血压差、有无镇痛情况,分析术后早期再出血的影响因素。结果:本研究共纳入465例患者,其中术后早期再出血患者44例,未再出血患者421例,再出血发生率为9.46%(44/465)。高血压脑出血术后早期再出血患者的术后收缩压、有无镇痛、血压差、血压波动与未再出血患者比较差异具有统计学意义(P0.05)。术后早期再出血患者的年龄、性别及术前GCS评分、出血量、术前收缩压、镇静时间、插管时间、有无使用止血药与未再出血患者比较差异无统计学意义(P0.05)。多因素Logistic回归分析显示,患者血压波动大是术后早期再出血的危险因素,手术前后血压差大、术后使用镇痛治疗是其保护因素。结论:高血压脑出血患者术后血压波动、手术前后血压差及术后镇痛治疗均是早期再出血的影响因素,合理降压及镇痛治疗可减少脑出血术后早期再出血的发生。     

蒙药材刺柏叶中槲皮苷的含量测定

本实验建立了蒙药材刺柏叶中槲皮苷的HPLC含量测定方法.色谱条件为:Diamonsil C18(4.6 mm ×250 mm,5μm)和Shim-Pack C18(4.6 mm× 250 mm,5μm),流动相:甲醇-0.01 mol/L磷酸二氢钾溶液-冰醋酸(40∶ 60∶ 1.5),检测波长:254 nm,流速:1.0 mL/min,柱温:30℃.槲皮苷进样量在40.2 ng ～603.0 ng范围内线性关系良好(r =0.9998),其平均加样回收率为100.45％,RSD为0.69％(n=6).本方法简便易行,结果准确,重复性好,可用于刺柏叶中槲皮苷的含量测定.     

UDP-glucuronic acid decarboxylases of Bacteroides fragilis and their prevalence in bacteria

Xylose is rarely described as a component of bacterial glycans. UDP-xylose is the nucleotide-activated form necessary for incorporation of xylose into glycans and is synthesized by the decarboxylation of UDP-glucuronic acid (UDP-GlcA). Enzymes with UDP-GlcA decarboxylase activity include those that lead to the formation of UDP-xylose as the end product (Uxs type) and those synthesizing UDP-xylose as an intermediate (ArnA and RsU4kpxs types). In this report, we identify and confirm the activities of two Uxs-type UDP-GlcA decarboxylases of Bacteroides fragilis, designated BfUxs1 and BfUxs2. Bfuxs1 is located in a conserved region of the B. fragilis genome, whereas Bfuxs2 is in the heterogeneous capsular polysaccharide F (PSF) biosynthesis locus. Deletion of either gene separately does not result in the loss of a detectable phenotype, but deletion of both genes abrogates PSF synthesis, strongly suggesting that they are functional paralogs and that the B. fragilis NCTC 9343 PSF repeat unit contains xylose. UDP-GlcA decarboxylases are often annotated incorrectly as NAD-dependent epimerases/dehydratases; therefore, their prevalence in bacteria is underappreciated. Using available structural and mutational data, we devised a sequence pattern to detect bacterial genes encoding UDP-GlcA decarboxylase activity. We identified 826 predicted UDP-GlcA decarboxylase enzymes in diverse bacterial species, with the ArnA and RsU4kpxs types confined largely to proteobacterial species. These data suggest that xylose, or a monosaccharide requiring a UDP-xylose intermediate, is more prevalent in bacterial glycans than previously appreciated. Genes encoding BfUxs1-like enzymes are highly conserved in Bacteroides species, indicating that these abundant intestinal microbes may synthesize a conserved xylose-containing glycan.     

Rhinovirus-induced barrier dysfunction in polarized airway epithelial cells is mediated by NADPH oxidase 1

Previously, we showed that rhinovirus (RV), which is responsible for the majority of common colds, disrupts airway epithelial barrier function, as evidenced by reduced transepithelial resistance (R(T)), dissociation of zona occludins 1 (ZO-1) from the tight junction complex, and bacterial transmigration across polarized cells. We also showed that RV replication is required for barrier function disruption. However, the underlying biochemical mechanisms are not known. In the present study, we found that a double-stranded RNA (dsRNA) mimetic, poly(I:C), induced tight junction breakdown and facilitated bacterial transmigration across polarized airway epithelial cells, similar to the case with RV. We also found that RV and poly(I:C) each stimulated Rac1 activation, reactive oxygen species (ROS) generation, and Rac1-dependent NADPH oxidase 1 (NOX1) activity. Inhibitors of Rac1 (NSC23766), NOX (diphenylene iodonium), and NOX1 (small interfering RNA [siRNA]) each blocked the disruptive effects of RV and poly(I:C) on R(T), as well as the dissociation of ZO-1 and occludin from the tight junction complex. Finally, we found that Toll-like receptor 3 (TLR3) is not required for either poly(I:C)- or RV-induced reductions in R(T). Based on these results, we concluded that Rac1-dependent NOX1 activity is required for RV- or poly(I:C)-induced ROS generation, which in turn disrupts the barrier function of polarized airway epithelia. Furthermore, these data suggest that dsRNA generated during RV replication is sufficient to disrupt barrier function.