Mechanical ventilation with high tidal volumes attenuates myocardial dysfunction by decreasing cardiac edema in a rat model of LPS-induced peritonitis

Background

Injurious mechanical ventilation (MV) may augment organ injury remote from the lungs. During sepsis, myocardial dysfunction is common and increased endothelial activation and permeability can cause myocardial edema, which may, among other factors, hamper myocardial function. We investigated the effects of MV with injuriously high tidal volumes on the myocardium in an animal model of sepsis.

Methods

Normal rats and intraperitoneal (i.p.) lipopolysaccharide (LPS)-treated rats were ventilated with low (6 ml/kg) and high (19 ml/kg) tidal volumes (Vt) under general anesthesia. Non-ventilated animals served as controls. Mean arterial pressure (MAP), central venous pressure (CVP), cardiac output (CO) and pulmonary plateau pressure (P_plat) were measured. Ex vivo myocardial function was measured in isolated Langendorff-perfused hearts. Cardiac expression of endothelial vascular cell adhesion molecule (VCAM)-1 and edema were measured to evaluate endothelial inflammation and leakage.

Results

MAP decreased after LPS-treatment and Vt-dependently, both independent of each other and with interaction. MV Vt-dependently increased CVP and Pplat and decreased CO. LPS-induced peritonitis decreased myocardial function ex vivo but MV attenuated systolic dysfunction Vt-dependently. Cardiac endothelial VCAM-1 expression was increased by LPS treatment independent of MV. Cardiac edema was lowered Vt-dependently by MV, particularly after LPS, and correlated inversely with systolic myocardial function parameters ex vivo.

Conclusion

MV attenuated LPS-induced systolic myocardial dysfunction in a Vt-dependent manner. This was associated with a reduction in cardiac edema following a lower transmural coronary venous outflow pressure during LPS-induced coronary inflammation.     

Solution structure and characterization of the DNA-binding activity of the B3BP-Smr domain

The MutS1 protein recognizes unpaired bases and initiates mismatch repair, which are essential for high-fidelity DNA replication. The homologous MutS2 protein does not contribute to mismatch repair, but suppresses homologous recombination. MutS2 lacks the damage-recognition domain of MutS1, but contains an additional C-terminal extension: the small MutS-related (Smr) domain. This domain, which is present in both prokaryotes and eukaryotes, has previously been reported to bind to DNA and to possess nicking endonuclease activity. We determine here the solution structure of the functionally active Smr domain of the Bcl3-binding protein (also known as Nedd4-binding protein 2), a protein with unknown function that lacks other domains present in MutS proteins. The Smr domain adopts a two-layer α-β sandwich fold, which has a structural similarity to the C-terminal domain of IF3, the R3H domain, and the N-terminal domain of DNase I. The most conserved residues are located in three loops that form a contiguous, exposed, and positively charged surface with distinct sequence identity for prokaryotic and eukaryotic Smr domains. NMR titration experiments and DNA binding studies using Bcl3-binding protein-Smr domain mutants suggested that these most conserved loop regions participate in DNA binding to single-stranded/double-stranded DNA junctions. Based on the observed DNA-binding-induced multimerization, the structural similarity with both subdomains of DNase I, and the experimentally identified DNA-binding surface, we propose a model for DNA recognition by the Smr domain.     

香菇的学名及其在当代真菌分类中的位置

本文综述了香菇(Lentinula edodes)的分类历史,确认其在蘑菇目(Agaricales)Tricholomataceae科下的分类地位,并证实了它与多孔菌目(Poriales)Lentinaceae科的Lentinus属没有联系。根据《真菌、地衣汉语学名命名法规》,作者讨论了译为“香菇属”的Lentinus和“小香菇属”的Lentinellus两属的汉语学名问题,提出Lentinus的汉语学名应订正为“韧伞属”,Lentinellus为“螺壳菌属”。香菇所在的Lentinula属的汉语学名建议为“木菇属”。     

A new repetitive element of the CR1 family downstream of the chicken vitellogenin gene.

We have analyzed a repetitive DNA sequence found in the 3'-flanking region of the chicken vitellogenin gene. By its sequence, the repetitive DNA has been identified as a hitherto unreported member of the chicken CR1 family of repetitive elements. The CR1 sequence displays the structural characteristics of a long terminal repeat located at the 3' end of an avian retrovirus. The CR1 element lies 2.2 kb downstream of the vitellogenin gene and 'points' away from the gene rather than toward it. In this respect, this element differs from other CR1 repeats. The CR1 element is embedded in a region showing changes in chromatin structure implying a potential role for this sequence in determining the structural state of the local chromatin.     

Bioethanol production from the hydrolysate of Palmaria palmata using sulfuric acid and fermentation with brewer’s yeast

Seaweeds, particularly species of red macroalgae, are promising resources for bioethanol production because of their exceptionally high carbohydrate content. Of 20 seaweeds evaluated, Palmaria palmata (Rhodymenia palmata) contained the highest carbohydrate content (469.8 mg g^?1 seaweed) with a carrageenan content of 354 mg g^?1 seaweed. Such a high carrageenan content makes the high-volume production of bioethanol feasible. Acid hydrolysis of P. palmata in 0.4 M H₂SO₄ at 125 °C for 25 min released 27 mg of glucose, 218.4 mg of reducing sugars, and 127.6 mg of galactose per gram of seaweed. Ethanol fermentation of these hydrolysis products using an inoculum concentration of 1.5 mg mL^?1 at 30 °C and 72 h in a shaking incubator at 130 rpm yielded 17.3 mg of ethanol per gram of seaweed.     

突尼斯非洲跳鼠（Jaculus jaculus）和埃及跳鼠J.orientalis）群体的等位酶多态及遗传分化

运用16种酶蛋白编码的23个遗传座位对突尼斯非洲跳鼠(Jaculus jaculus)和埃及跳鼠(J.orientalis)自然群体的遗传变异和分化进行了电泳分析.结果表明,与其他啮齿动物等哺乳动物的相关数据比较,发现这两个种群体的遗传变异水平较低.非洲跳鼠群体的观测杂合度(Hobs)为0.08-0.19,多态座位百分比(P)为26.2%-45.2%,每个座何的平均等位基因数(A)为1.1-1.4;埃及跳鼠的Hobs为0.10-0.15,P为29.3%-44.1%,A为1.1-1.7.两个种群体各自的遗传分化程度较低(非洲跳鼠和埃及跳鼠的Fst分别为0.0017和0.0019).而两个种群体间的Fst为0.607(P＜0.05),表明两个种之间高度的遗传分化.本研究支持这两个种分类地位的合法性,并强调了地理因素(环境类犁和生物气候阶段)对两个种遗传结构的影响.     

A reliable measure of similarity based on dependency for short time series: an application to gene expression networks

Background  

Microarray techniques have become an important tool to the investigation of genetic relationships and the assignment of different phenotypes. Since microarrays are still very expensive, most of the experiments are performed with small samples. This paper introduces a method to quantify dependency between data series composed of few sample points. The method is used to construct gene co-expression subnetworks of highly significant edges.     

Effects of 3-beta-diol, an androgen metabolite with intrinsic estrogen-like effects, in modulating the aquaporin-9 expression in the rat efferent ductules

Background  

Fluid homeostasis is critical for normal function of the male reproductive tract and aquaporins (AQP) play an important role in maintenance of this water and ion balance. Several AQPs have been identified in the male, but their regulation is not fully comprehended. Hormonal regulation of AQPs appears to be dependent on the steroid in the reproductive tract region. AQP9 displays unique hormonal regulation in the efferent ductules and epididymis, as it is regulated by both estrogen and dihydrotestosterone (DHT) in the efferent ductules, but only by DHT in the initial segment epididymis. Recent data have shown that a metabolite of DHT, 5-alpha-androstane-3-beta-17-beta-diol (3-beta-diol), once considered inactive, is also present in high concentrations in the male and indeed has biological activity. 3-beta-diol does not bind to the androgen receptor, but rather to estrogen receptors ER-alpha and ER-beta, with higher affinity for ER-beta. The existence of this estrogenic DHT metabolite has raised the possibility that estradiol may not be the only estrogen to play a major role in the male reproductive system. Considering that both ER-alpha and ER-beta are highly expressed in efferent ductules, we hypothesized that the DHT regulation of AQP9 could be due to the 3-beta-diol metabolite.