急性心肌梗死患者外周血中微小RNA-492表达水平及临床意义

目的 探究急性心肌梗死(acute myocardial infarction,AMI)患者外周血清微小RNA(miR)-492表达水平以及临床诊断意义.方法 选择2018年9月～2020年6月广东医科大学附属医院急诊科就诊的老年AMI患者248例为研究组,选择同期冠状动脉造影正常者248例为对照组.检测2组血清肌钙蛋...     

Comparison of high-frequency oscillatory ventilation and high-frequency jet ventilation in cats with normal lungs

Four adult cats received alternating high-frequency oscillatory ventilation (HFOV) and high-frequency jet ventilation (HFJV) at equivalent proximal airway pressures. Physiologic measurements were made before and after each ventilator change. Proximal airway pressures were then adjusted as necessary to reestablish normal pH and PaCO2 values. Aortic, pulmonary artery, and central venous pressures were monitored. Cardiac outputs were measured. Pulmonary and systemic vascular resistance, intrapulmonary shunt, and alveolar-arterial oxygen gradient were determined. Following the change from HFOV to HFJV at similar proximal airway pressures, HFJV always produced higher pH values (P less than 0.0001), higher PaO2 values (P less than 0.05), lower PaCO2 values (P less than 0.0001), as well as higher cardiac outputs (P less than 0.01), lower pulmonary artery pressures (P less than 0.001), and lower pulmonary vascular resistances (P less than 0.001). Following the reciprocal crossover, from HFJV to HFOV, HFJV pH values were again higher (P less than 0.001), and PaCO2 values were again lower (P less than 0.001). A comparison of HFOV and HFJV at similar pH and PaCO2 values showed that HFOV consistently required higher peak inspiratory pressures (P less than 0.001), higher mean airway pressure (P less than 0.001), and higher pressure wave amplitudes (P less than 0.001). Under the circumstances of this study, HFJV produced better gas exchange at lower proximal airway pressures.     

Variable expression of extracellular polysaccharide in the marine bacterium Pseudomonas atlantica is controlled by genome rearrangement

Production of extracellular polysaccharide by the marine bacterium Pseudomonas atlantica is a variable trait. Strains that produce extracellular polysaccharide (EPS⁺) have a mucoid colony phenotype, but during cultivation in the laboratory nonmucoid, EPS^- variants arise that have a crenated colony morphology. This change is reversible since crenated variants rapidly switch to the original mucoid phenotype. We have cloned the locus (eps) controlling variable expression of EPS production by screening a recombinant cosmid library for clones that restore EPS production in the crenated variant. By using eps as a probe of genomic structure in variant strains, expression of EPS production was found to be controlled by a specific DNA rearrangement. Insertion of a 1.2-kilobase-pair DNA sequence in the eps locus results in EPS^-, whereas excision of the sequence restores the EPS⁺ phenotype. Properties of the rearrangement suggest the involvement of a mobile genetic element. The possible significance of this DNA rearrangement to the survival of P. atlantica in the ocean is discussed.     

Isolation of inverted repeat sequences, including IS1, IS2, and IS3, in Escherichia coli plasmids.

A method is described for isolation of inverted repeat DNA sequences that occur in E. coli plasmids. The procedures of the isolation involved: (a) denaturation of intact plasmid DNA, (b) a rapid, 30 sec, renaturation of inverted-repeat sequences in the genome, (c) digestion of the single-stranded portion by S1 nuclease to recover duplex DNA, and (d) detection and purification of the duplexes using 1.4% agarose gel electrophoresis. If a plasmid DNA carried inverted repeats of either one type or two different types of special DNA sequences, these procedures enabled us to observe either one or two characteristic DNA bands, respectively, in the agarose gels. If a plasmid DNA did not carry any inverted repeats, or if the plasmid DNA only carried direct repeat sequences, no characteristic DNA bands were recovered. Cleavage of the spacer DNA between inverted repeat sequences generated no gel bands. This indicated that the inverted repeat sequences must be in the same strand. Using this method, we isolated and purified several repeated sequences, including IS1, IS2, and IS3, from derivatives of F and R plasmids.     

Chromosomal markers in study of colon cancer

Conclusions Examination of a relatively small subset of information pertaining to colon tumors indicates that examples in each category (including predisposing markers of chromosomal instability, causally relevant markers, correlation between karyotypic atypia and biological malignancy, and some tumors with no detectable chromosome changes) can all be found. This discussion began with questions about the purposes that markers could serve: some of those questions with reference to colon tumors can be answered. For the most part, the presence of chromosomal aberrations can indeed distinguish between the normal and the tumor cell and, in this sense, help to define the tumor. Moreover, some specific chromosomal alterations appear to be preferentially associated with colon tumors. If the specificity can be better defined, then, like the other specific tumor-chromosome associations, those in colonic mucosa may help to identify and localize gene functions important in the growth, development, or regulation of this specialized tissue. In any event, chromosomal aberrations are of value, not only in confirming the diagnosis, but also by their associations with different behavioral patterns in both malignant and premalignant lesions. Their definition, therefore, may have predictive value for the individual patient. In particular, inability to find such alterations, while it is not evidence of a nontumorous state, in a known malignancy may at least contribute some information about the biology of that particular tumor.The second question was whether markers could be of value in identifying stages in the evolution from a normal to a tumor cell. From the work done thus far on chromosomal instability, it appears likely, when more data are accumulated and the appropriate tests can be standardized, that proof of chromosomal instability may indeed constitute a marker for certain specific tumor-predisposing states. Similarly, the oncogenes, whose normal genomic counterparts are clearly responsible for important functions relating to cell growth and regulation, may prove to be markers for only a limited number of tumors. However, their definition and the resultant contributions to understanding the basic cellular biology of normal and tumor cells should make it possible to identify some of the critical steps that are altered in the multiple pathways leading to tumor.     

Chromosomal aberrations in a case of erythroleukaemia

Summary Bone marrow cells from a 49 years old man with erythroleukaemia revealed an extreme form of chromosomal number variation ranging from 39 to 135. The presence of these sub-lines is interpreted as a feature of malignancy. Minute elements and dicentric like chromosomes were also present.

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Zusammenfassung In den Knochenmarkzellen eines 49 Jahre alten Kranken mit Erythroleukämie fand sich eine hohe Zahl numerischer chromosomaler Aberrationen mit Chromosomenzahlen zwischen 39 und 135. Diese Stammlinienvariationen werden als Zeichen der Malignität gedeutet.Außerdem waren kleine Fragmente und dicentrischen Chromosomen ähnelnde Elemente nachweisbar.

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This case was reported in short in the thesis presented to the Faculty of Science, Hokkaido University, in partial fullfilment for the requirements of the degree of Doctor of Science.     

Detection of Mycobacterium tuberculosis in clinical samples using insertion sequences IS6110 and IS990

To detect Mycobacterium tuberculosis in clinical samples, we used the M. tuberculosis-complex specific insertion sequence IS990 as the target in a simple DIG-PCR ELISA assay, as this element is present as a single copy in all strains of M. tuberculosis we have examined to date. The IS990 test was compared with a similar PCR that utilizes IS6110 as target. For detection of PCR product, digoxigenin-11-dUTP (DIG-dUTP) was incorporated into the product. After amplification, the PCR product was hybridized with biotinylated capture probe, which was complementary to the inner part of the amplicon. The hybrid was captured onto streptavidin-coated microtiter plate and DIG-labeled PCR product was detected using a peroxidase-conjugated antibody to DIG. We evaluated DIG-PCR ELISA for the detection of M. tuberculosis DNA in 265 respiratory and non-respiratory specimens taken from patients with known and suspected tuberculosis disease or from controls. The sensitivity and specificity of both IS990-based test and IS6110-based test was 96.5% and 95.3% respectively, comparable to the sensitivity and specificity of the IS6110-based test. The results demonstrate that the IS990 PCR ELISA test is a rapid and sensitive tool for the detection and identification of M. tuberculosis in clinical samples, and may have advantages to the more widely used IS6110-based tests, particularly in areas where IS6110-negative strains are found.     

Chromosomal Aberrations in Peripheral Lymphocytes of Abstinent Alcoholics

The frequency of structural and/or numerical chromosomal aberrations in human metaphasic cells of lymphocyte cultures from abstinent alcoholics who were abstinent for 1 month up to 32 years was compared with those from controls not selected for alcohol consumption. Cytogenetic analyses revealed a significant increase of the frequencies of cells with structural aberrations in the abstinent alcoholics (7.1 %), compared with controls (2.4%). The frequency of numerical aberrations showed a significant regression on ages in abstinent alcoholics and controls. These results suggest specific action of chronic alcohol consumption impairing biological repair with aging. The increased frequency of chromosome-type aberrations associated with alcohol consumption, even after long withdrawal, could be due to an action of ethanol or its metabolites on primordial leukopoietic cells.     

Hemodynamic effects of high-frequency oscillatory ventilation in children

The purpose of this study was to evaluate the acute hemodynamic effects of transitioning a patient from conventional mechanical ventilation (CMV) to high-frequency oscillatory ventilation (HFOV). Our hypothesis was that hemodynamic status would not be adversely affected by such a change. Ten pediatric patients with acute hypoxemic respiratory failure and a thermodilution pulmonary arterial catheter in place were prospectively evaluated on the transition from CMV to HFOV. Hemodynamic and respiratory data were obtained before and within 1 hour of transition to HFOV with a “high-volume” ventilation strategy. On CMV, the mean oxygenation index of the patients was 18 ± 4. Despite increases in mean airway pressure and decreases in mean arterial pressure and systemic vascular resistance on HFOV, there was no change in pulmonary circulation variables, cardiac index, or oxygen delivery. We concluded that in pediatric patients with acute respiratory failure and unstable cardiovascular status, the transition from CMV to HFOV was not accompanied by a decrease in cardiac function or oxygen delivery. Pediatr Pulmonol. 1998; 25:371–374. © 1998 Wiley-Liss, Inc.     

Chromosomal Control of Mating Activity in Drosophila pseudoobscura

Lines containing two third-chromosome inversions (Arrowhead and Pikes Peak) of Drosophila pseudoobscura selected for fast and slow mating speed were crossed to a multichromosomal, dominant marker inversion stock, and strains with various combinations of chromosomal derivation were tested for their mating activity. When lines were selected isodirectionally with the known third-chromosome control, the third chromosome was found to possess major epistatic control over mating speed, followed by the fourth, with no appreciable effect from the first and second. However, polygenic modification mating activity was found throughout the genome when selection was applied opposite to the original third-chromosome control. The work reported here strengthens the evidence that the adaptive role of chromosomal polymorphism has a behavioral basis in mating activity.     

闭合式切除术在直肠癌腹腔镜全系膜切除根治术中的应用效果研究

目的评价闭合式切除术（CE）在直肠癌腹腔镜全系膜切除（TME）根治术中的临床应用效果。 方法以潍坊医学院附属寿光市人民医院2011年2月至2014年6月收治的54例原发性直肠癌患者为研究对象,30例为实验组进行CE＋ TME腹腔镜根治术,24例为对照组进行TME腹腔镜根治术。术中均联合动脉灌注化疗。比较两组患者手术时间、术中出血量、淋巴结清扫数目、环周切缘（CRM）阳性比例、术后恢复饮食时间、肛门排气时间、尿管留置时间、住院时间、术后并发症发生比例及术后1年局部复发比例等指标。 结果术中出血量（t=11.775,P<0.001)显著低于TME组,CE＋TME组手术时间（t=2.207,P=0.035）、术后肛门排气时间（t=2.059,P=0.045）、导尿管置留时间（t=2.083,P=0.042）、术后1年内局部复发率（χ²=3.97,P=0.047）显著低于TME组;淋巴结清扫数目显著高于TME组（t=9.613,P<0.001）。 结论CE可显著降低TME术后局部复发率,具有一定的临床应用价值。     

A new class of oxidosqualene cyclases directs synthesis of antimicrobial phytoprotectants in monocots

Many plants synthesize antimicrobial secondary metabolites as part of their normal program of growth and development, often sequestering them in tissues where they may protect against microbial attack. These include glycosylated triterpenoids (saponins), natural products that are exploited by man for a variety of purposes including use as drugs [Hostettmann, K. & Marston, A. (1995) Saponins (Cambridge Univ. Press, Cambridge, U.K.)]. Very little is known about the genes required for the synthesis of this important family of secondary metabolites in plants. Here we show the novel oxidosqualene cyclase AsbAS1 catalyzes the first committed step in the synthesis of antifungal triterpenoid saponins that accumulate in oat roots. We also demonstrate that two sodium azide-generated saponin-deficient mutants of oat, which define the Sad1 genetic complementation group, are defective in the gene encoding this enzyme and provide molecular genetic evidence indicating a direct link between AsbAS1, triterpenoid saponin biosynthesis, and disease resistance. Orthologs of AsbAS1 are absent from modern cereals and may have been lost during selection, raising the possibility that this gene could be exploited to enhance disease resistance in crop plants.