Intestinal bacterial overgrowth in the early stage of severe acute pancreatitis is associated with acute respiratory distress syndrome

BACKGROUNDIn the early stage of acute pancreatitis (AP), a large number of cytokines induced by local pancreatic inflammation seriously damage the intestinal barrier function, and intestinal bacteria and endotoxins enter the blood, causing inflammatory storm, resulting in multiple organ failure, infectious complications, and other disorders, eventually leading to death. Intestinal failure occurs early in the course of AP, accelerating its development. As an alternative method to detect small intestinal bacterial overgrowth, the hydrogen breath test is safe, noninvasive, and convenient, reflecting the number of intestinal bacteria in AP indirectly. This study aimed to investigate the changes in intestinal bacteria measured using the hydrogen breath test in the early stage of AP to clarify the relationship between intestinal bacteria and acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Early clinical intervention and maintenance of intestinal barrier function would be highly beneficial in controlling the development of severe acute pancreatitis (SAP).AIMTo analyze the relationship between intestinal bacteria change and ALI/ARDS in the early stage of SAP.METHODSA total of 149 patients with AP admitted to the intensive care unit of the Digestive Department, Xuanwu Hospital, Capital Medical University from 2016 to 2019 were finally enrolled, following compliance with the inclusion and exclusion criteria. The results of the hydrogen breath test within 1 wk of admission were collected, and the hydrogen production rates at admission, 72 h, and 96 h were calculated. The higher the hydrogen production rates the more bacteria in the small intestine. First, according to the improved Marshall scoring system in the 2012 Atlanta Consensus on New Standards for Classification of Acute Pancreatitis, 66 patients with a PaO₂/FiO₂ score ≤ 1 were included in the mild AP (MAP) group, 18 patients with a PaO₂/FiO₂ score ≥ 2 and duration < 48 h were included in the moderately SAP (MSAP) group, and 65 patients with a PaO₂/FiO₂ score ≥ 2 and duration > 48 h were included in the SAP group, to analyze the correlation between intestinal bacterial overgrowth and organ failure in AP. Second, ALI (PaO₂/FiO₂ = 2) and ARDS (PaO₂/FiO₂ > 2) were defined according to the simplified diagnostic criteria proposed by the 1994 European Union Conference. The MSAP group was divided into two groups according to the PaO₂/FiO₂ score: 15 patients with PaO₂/FiO₂ score = 2 were included in group A, and three patients with score > 2 were included in group B. Similarly, the SAP group was divided into two groups: 28 patients with score = 2 were included in group C, and 37 patients with score > 2 were included in group D, to analyze the correlation between intestinal bacterial overgrowth and ALI/ARDS in AP.RESULTSA total of 149 patients were included: 66 patients in the MAP group, of whom 53 patients were male (80.3%) and 13 patients were female (19.7%); 18 patients in the MSAP group, of whom 13 patients were male (72.2%) and 5 patients were female (27.8%); 65 patients in the SAP group, of whom 48 patients were male (73.8%) and 17 patients were female (26.2%). There was no significant difference in interleukin-6 and procalcitonin among the MAP, MSAP, and SAP groups (P = 0.445 and P = 0.399, respectively). There was no significant difference in the growth of intestinal bacteria among the MAP, MSAP, and SAP groups (P = 0.649). There was no significant difference in the growth of small intestinal bacteria between group A and group B (P = 0.353). There was a significant difference in the growth of small intestinal bacteria between group C and group D (P = 0.038).CONCLUSIONIntestinal bacterial overgrowth in the early stage of SAP is correlated with ARDS.     

糖皮质激素在重症急性呼吸综合征治疗中的应用

传染性非典型肺炎 ,世界卫生组织命名为重症急性呼吸综合征 (SARS) ,是一种由变异冠状病毒感染引起的新的呼吸道传染性疾病。自从 2 0 0 2年底以来 ,首先在广东报道 ,全球先后有 31个国家和地区受累 ,报告病例 84 37例 ,死亡 813例 (截至 2 0 0 3年 7月 11日 )。起病急 ,以发热为首发症状 ,体温一般 >38℃ ,可有咳嗽、咳白痰或血丝痰 ,严重者出现呼吸加速、气促或明显呼吸窘迫 ,X线胸片病灶常进行性发展 ,于病程第 2周达高峰 ,部分病例发展为I型呼吸衰竭 ,达到急性肺损伤或急性呼吸窘迫综合征的诊断标准。SARS常继发感染而引起严重并发…     

严重急性呼吸综合征冠状病毒核衣壳蛋白对环氧合酶-2表达的影响

目的 探讨严重急性呼吸综合征冠状病毒(SARS-CoV)核衣壳蛋白对环氧合酶-2(COX-2)表达的影响.方法 将带有COX-2基因启动子的报告质粒分别与表达SARS-CoV基因组的单个基因的质粒共转染293T细胞,并测定荧光素酶的活性,采用RT-PCR和Western印迹法检测COX-2 mRNA和蛋白表达的变化.结果 SARS-CoV核衣壳蛋白能显著激活COX-2基因启动子的活性,并在mRNA和蛋白水平上调COX-2的表达,且这种激活作用随着核衣壳蛋白浓度的增加而增强.结论 SARS-CoV核衣壳蛋白能特异性地激活COX-2的表达.     

Structure of a proteolytically resistant core from the severe acute respiratory syndrome coronavirus S2 fusion protein

A coronavirus (CoV) has recently been identified as the causative agent of the severe acute respiratory syndrome (SARS) in humans. CoVs enter target cells through fusion of viral and cellular membranes mediated by the viral envelope glycoprotein S. We have determined by x-ray crystallography the structure of a proteolytically stable core fragment from the heptad repeat (HR) regions HR1 and HR2 of the SARS-CoV S protein. We have also determined the structure of an HR1-HR2 S core fragment, containing a shorter HR1 peptide and a C-terminally longer HR2 peptide that extends up to the transmembrane region. In these structures, three HR1 helices form a parallel coiled-coil trimer, whereas three HR2 peptides pack in an oblique and antiparallel fashion into the coiled-coil hydrophobic grooves, adopting mixed extended and alpha-helical conformations as in postfusion paramyxoviruses F proteins structures. Our structure positions a previously proposed internal fusion peptide adjacent to the N-terminus of HR1. Peptides from the HR2 region of SARS-CoV S have been shown to inhibit viral entry and infection in vitro. The structures presented here can thus open the path to the design of small-molecule inhibitors of viral entry and candidate vaccine antigens against this virus.     

The central structural feature of the membrane fusion protein subunit from the Ebola virus glycoprotein is a long triple-stranded coiled coil

The ectodomain of the Ebola virus Gp2 glycoprotein was solubilized with a trimeric, isoleucine zipper derived from GCN4 (pIIGCN4) in place of the hydrophobic fusion peptide at the N terminus. This chimeric molecule forms a trimeric, highly α-helical, and very thermostable molecule, as determined by chemical crosslinking and circular dichroism. Electron microscopy indicates that Gp2 folds into a rod-like structure like influenza HA2 and HIV-1 gp41, providing further evidence that viral fusion proteins from diverse families such as Orthomyxoviridae (Influenza), Retroviridae (HIV-1), and Filoviridae (Ebola) share common structural features, and suggesting a common membrane fusion mechanism.     

Escherichia coli DnaX product, the tau subunit of DNA polymerase III, is a multifunctional protein with single-stranded DNA-dependent ATPase activity.

The dnaZX gene of Escherichia coli directs the synthesis of two proteins, DnaZ and DnaX. These products are confirmed as the gamma and tau subunits of DNA polymerase III because antibody to a synthetic peptide present in both the DnaZ and DnaX proteins reacts also with the gamma and tau subunits of holoenzyme. To characterize biochemically the tau subunit, for which there has been no activity assay, the dnaZX gene was fused to the beta-galactosidase gene to encode a fusion product in which the 20 C-terminal amino acids of the DnaX protein (tau) were replaced by beta-galactosidase lacking only 7 N-terminal amino acids. The 185-kDa fusion protein, which retained beta-galactosidase activity, was overproduced to the level of about 5% of the soluble cellular protein by placing the gene fusion under control of the tac promoter and Shine-Dalgarno sequence. The fusion protein was isolated in one step by affinity chromatography on p-aminobenzyl 1-thio-beta-D-galactopyranoside-agarose. The purified fusion protein also had ATPase (and dATPase) activity that was dependent on single-stranded DNA. This activity copurified with the beta-galactosidase activity not only through the affinity column but also through a subsequent gel filtration. We conclude that the DnaX protein function involves binding to single-stranded DNA and hydrolysis of ATP or dATP, in addition to binding to other DNA polymerase III holoenzyme components, increasing the processivity of the core enzyme, and serving as a substrate for the production of the gamma subunit.     

Changes in virus detection in hospitalized children before and after the severe acute respiratory syndrome coronavirus 2 pandemic

The impact of strengthening preventive measures against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection on the prevalence of respiratory viruses in children was examined. After the SARS‐CoV‐2 pandemic, the rate of multiple virus detection among hospitalized children decreased. Immediately after the SARS‐CoV‐2 pandemic, respiratory syncytial and parainfluenza viruses were rarely detected and subsequently reemerged. Human metapneumovirus and influenza virus were not consistently detected. Non‐enveloped viruses (bocavirus, rhinovirus, and adenovirus) were detected to some extent even after the pandemic. Epidemic‐suppressed infectious diseases may reemerge as susceptibility accumulates in the population and should continue to be monitored.     

糖皮质激素治疗重症急性呼吸综合征初探

目的　探讨糖皮质激素对重症急性呼吸综合征 (SARS)病情的影响。方法　定期观察我院自 2 0 0 3年 3月 2 6日至 5月初收治的SARS病人 30例 ,病程均为 3周以上。统计激素治疗的时间和剂量 ,观察治疗前后CD+ 4 、CD+ 8、CD+ 3 T淋巴细胞计数 ,以及电解质、血象、血清白蛋白变化。结果　激素治疗前 2 7例患者CD+ 4 、CD+ 8、CD+ 3 T淋巴细胞计数分别为 (个 / μl ) 4 0 1± 2 0 3、340± 187、75 6± 383。30例中 2 9例使用甲泼尼龙治疗 ,2 4例剂量为 80～ 16 0mg/d ,最大剂量为 10 0 0mg/d(入我院前 )。应用激素后血白细胞升高 (P <0 .0 1) ;血K+ 、Na+ 、Cl-无明显变化 (P >0 .0 5 ) ;血糖升高 (P =0 .0 1) ;血清白蛋白明显下降 (P <0 .0 1) ;较大剂量的激素可明显抑制CD+ 4 、CD+ 8、CD+ 3 T淋巴细胞的水平 ;3例重症病例在大剂量激素应用下出现二重感染。结论　SARS病人在病程早期免疫功能已受到抑制 ,大剂量应用糖皮质激素可明显加重这一抑制 ,并使机体处于高代谢状态 (血糖升高、血清白蛋白下降 ) ,进一步导致病情加重 ,病人在后期易出现严重继发感染 ,因此应严格掌握激素适应证 ,不宜大剂量使用。     

The RNA-binding protein, TB-RBP, is the mouse homologue of translin, a recombination protein associated with chromosomal translocations

The mouse RNA-binding protein, TB-RBP, suppresses translation in vitro and attaches mRNAs to microtubules by binding to conserved elements in the 3′ untranslated regions of specific mRNAs. We have now purified TB-RBP from testicular and brain cytoplasmic extracts and cloned its cDNA. We find that the mouse TB-RBP cDNAs contain an open reading frame of 228 amino acids with a leucine zipper domain within its C terminus, a transmembrane helix, and a group of putative phosphorylation sites. TB-RBP shows 99% identity to the human protein, translin, a recombination hotspot-binding protein associated with chromosomal translocations [Aoki, K., Suzuki, K., Sugano, T., Tasaka, T., Nakahara, K., Kuge, O., Omori, A. & Kasai, M. (1995) Nat. Genet. 10, 167–174]. As shown for translin, TB-RBP also binds to single-stranded DNAs containing a broad range of consensus sequences, many of which are similar to the Y and H RNA-binding sequences. Recombinant TB-RBP was synthesized and an antiserum was prepared against the recombinant protein. The identity between translin and TB-RBP was confirmed by demonstrating that immunoprecipitation of TB-RBP from testicular extracts abolished formation of the RNA-TB–RBP complex. Based upon its DNA binding to target sequences in clustered breakpoint regions, we propose that TB-RBP may be involved in DNA recombination or DNA repair in male germ cells.     

Evidence that the polymerase of respiratory syncytial virus initiates RNA replication in a nontemplated fashion

RNA virus polymerases must initiate replicative RNA synthesis with extremely high accuracy to maintain their genome termini and to avoid generating defective genomes. For the single-stranded negative-sense RNA viruses, it is not known how this accuracy is achieved. To investigate this question, mutations were introduced into the 3′ terminal base of a respiratory syncytial virus (RSV) template, and the RNA products were examined to determine the impact of the mutation. To perform the assay, RNA replication was reconstituted using a modified minireplicon system in which replication was limited to a single step. Importantly, this system allowed analysis of RSV RNA generated intracellularly, but from a defined template that was not subject to selection by replication. Sequence analysis of RNA products generated from templates containing 1U-C and 1U-A substitutions showed that, in both cases, replication products were initiated with a nontemplated, WT A residue, rather than a templated G or U residue, indicating that the polymerase selects the terminal NTP independently of the template. Examination of a template in which the position 1 nucleotide was deleted supported these findings. This mutant directed efficient replication at ∼60% of WT levels, and its product was found to be initiated at the WT position (−1 relative to the template) with a WT A residue. These findings show that the RSV replicase selects ATP and initiates at the correct position, independently of the first nucleotide of the template, suggesting a mechanism by which highly accurate replication initiation is achieved.     

北京市建立重症急性呼吸综合征病历数据库的意义

重症急性呼吸综合征(SARS)是人类进入新世纪后面临的一种新型强烈传染性疾病。自2002年11月起,疫情迅速蔓延至全球32个国家和地区,截至2003年7月11日,全球发病人数达到8437例,其中死亡813例,全球病死率接近10％。在我国,疫情首发于广东,而以北京最为严重,从2003年3月出现第1例输入性病例开始,到2003年6月25日世界卫生组织解除北京地区的疫区地位和旅行警告为止,共报告SARS病例2521例。     

The neuronal RNA-binding protein Nova-2 is implicated as the autoantigen targeted in POMA patients with dementia

Paraneoplastic opsoclonus myoclonus ataxia (POMA) is a neurologic disorder thought to be mediated by an autoimmune attack against onconeural disease antigens that are expressed by gynecologic or lung tumors and by neurons. One POMA disease antigen, termed Nova-1, has been identified as a neuron-specific KH-type RNA-binding protein. Nova-1 expression is restricted to specific regions of the central nervous system, primarily the hindbrain and ventral spinal cord, which correlate with the predominantly motor symptoms in POMA. However, POMA antisera recognize antigens that are widely expressed in both caudal and rostral regions of the central nervous system, and some patients develop cognitive symptoms. We have used POMA antisera to clone a cDNA encoding a second POMA disease antigen termed Nova-2. Nova-2 is closely related to Nova-1, and is expressed at high levels in neurons during development and in adulthood, and at lower levels in the adult lung. In the postnatal mouse brain, Nova-2 is expressed in a pattern that is largely reciprocal with Nova-1, including high levels of Nova-2 expression in the neocortex and hippocampus. Functional characterization of Nova-2 in RNA selection and nitrocellulose filter-binding assays reveals that Nova-2 binds RNA with high affinity and with sequence specificity that differs from Nova-1. Our results demonstrate that the immune response in POMA targets a family of highly related sequence-specific neuronal RNA-binding proteins. The expression pattern of the Nova-2 protein is likely to underlie the development of cognitive deficits in some POMA patients.