Overview of CF lung pathophysiology

Defects of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein affect the homeostasis of chloride, bicarbonate, sodium, and water in the airway surface liquid, influencing the mucus composition and viscosity, which induces a severe condition of infection and inflammation along the whole life of CF patients. The introduction of CFTR modulators, novel drugs directly intervening to rescue the function of CFTR protein, opens a new era of experimental research. The review summarizes the most recent advancements to understand the characteristics of the infective and inflammatory pathology of CF lungs.     

The chondrocyte channelome: A narrative review

Chondrocytes are the main cells in the extracellular matrix (ECM) of articular cartilage and possess a highly differentiated phenotype that is the hallmark of the unique physiological functions of this specialised load-bearing connective tissue. The plasma membrane of articular chondrocytes contains a rich and diverse complement of membrane proteins, known as the membranome, which defines the cell surface phenotype of the cells. The membranome is a key target of pharmacological agents and is important for chondrocyte function. It includes channels, transporters, enzymes, receptors, and anchors for intracellular, cytoskeletal and ECM proteins and other macromolecular complexes. The chondrocyte channelome is a sub-compartment of the membranome and includes a complete set of ion channels and porins expressed in these cells. Many of these are multi-functional proteins with “moonlighting” roles, serving as channels, receptors and signalling components of larger molecular assemblies. The aim of this review is to summarise our current knowledge of the fundamental aspects of the chondrocyte channelome, discuss its relevance to cartilage biology and highlight its possible role in the pathogenesis of osteoarthritis (OA). Excessive and inappropriate mechanical loads, an inflammatory micro-environment, alternative splicing of channel components or accumulation of basic calcium phosphate crystals can result in an altered chondrocyte channelome impairing its function. Alterations in Ca²⁺ signalling may lead to defective synthesis of ECM macromolecules and aggravated catabolic responses in chondrocytes, which is an important and relatively unexplored aspect of the complex and poorly understood mechanism of OA development.     

From the Cover: Salt stress-induced Ca2+ waves are associated with rapid,long-distance root-to-shoot signaling in plants

Their sessile lifestyle means that plants have to be exquisitely sensitive to their environment, integrating many signals to appropriate developmental and physiological responses. Stimuli ranging from wounding and pathogen attack to the distribution of water and nutrients in the soil are frequently presented in a localized manner but responses are often elicited throughout the plant. Such systemic signaling is thought to operate through the redistribution of a host of chemical regulators including peptides, RNAs, ions, metabolites, and hormones. However, there are hints of a much more rapid communication network that has been proposed to involve signals ranging from action and system potentials to reactive oxygen species. We now show that plants also possess a rapid stress signaling system based on Ca²⁺ waves that propagate through the plant at rates of up to ∼400 µm/s. In the case of local salt stress to the Arabidopsis thaliana root, Ca²⁺ wave propagation is channeled through the cortex and endodermal cell layers and this movement is dependent on the vacuolar ion channel TPC1. We also provide evidence that the Ca²⁺ wave/TPC1 system likely elicits systemic molecular responses in target organs and may contribute to whole-plant stress tolerance. These results suggest that, although plants do not have a nervous system, they do possess a sensory network that uses ion fluxes moving through defined cell types to rapidly transmit information between distant sites within the organism.Plants are constantly tailoring their responses to current environmental conditions via a complex array of chemical regulators that integrate developmental and physiological programs across the plant body. Environmental stimuli are often highly localized in nature, but the subsequent plant response is often elicited throughout the entire organism. For example, soil is a highly heterogeneous environment and the root encounters stimuli that are presented in a patchy manner. Thus, factors including dry or waterlogged regions of the soil, variations in the osmotic environment, and stresses such as elevated levels of salt are all likely to be encountered locally by individual root tips, but the information may have to be acted on by the plant as a whole.In animals, long-range signaling to integrate activities across the organism occurs through rapid ionic/membrane potential-driven signaling through the nervous system in addition to operating via long-distance chemical signaling. Plants have also been proposed to possess a rapid, systemic communication network, potentially mediated through signals ranging from changes in membrane potential/ion fluxes (1–3) and levels of reactive oxygen species (ROS) (4, 5) to altered hydraulics in the vasculature (6). Even so, the molecular mechanisms behind rapid, systemic signaling in plants and whether such signals indeed carry regulatory information remains largely unknown. Suggestions that Ca²⁺ channels play a role in signals that occlude sieve tube elements (7), or that mediate systemic electrical signaling (2) in response to remote wounding, highlight Ca²⁺-dependent signaling events as a strong candidate for mediating some of these long-range responses. Similarly, cooling of roots elicits Ca²⁺ increases in the shoot within minutes (8), suggesting systemic signals can elicit Ca²⁺-dependent responses at distal sites within the plant. However, despite extensive characterization of Ca²⁺ signals (reviewed in ref. 9), their roles in a possible plant-wide communication network remain poorly understood. Therefore, to visualize how Ca²⁺ might act in local and systemic signaling, we generated Arabidopsis plants expressing the highly sensitive, GFP-based, cytoplasmic Ca²⁺ sensor YCNano-65 (10). We observed that a range of abiotic stresses including H₂O₂, touch, NaCl, and cold shock triggered Ca²⁺ increases at the point of application. However, NaCl also elicited a Ca²⁺ increase that moved away from the point of stress application. Propagation of this Ca²⁺ increase was associated with subsequent systemic changes in gene expression. We also report that this salt stress-induced long-distance Ca²⁺ wave is dependent on the activity of the ion channel protein Two Pore Channel 1 (TPC1), which also appears to contribute to whole-plant stress tolerance.     

脑外伤患者督脉穴位电刺激fMRI脑成像的初步观察

目的观察脑外伤患者督脉穴位电刺激的fMRI脑成像变化。方法对1例脑外伤患者进行命门穴和腰阳关穴经皮神经电刺激,对穴位刺激时的脑功能变化进行fMRI观察。结果与静息状态比较,电刺激时出现多个脑区激活。结论电刺激督脉可能会影响脑损伤后的神经可塑性过程。     

关节突关节形态与退变性腰椎滑脱的关系

目的 探讨关节突关节形态与退变性腰椎滑脱的方法。方法 首先对41例60岁以下（平均年龄55岁）有L4－5退变性滑脱的患者和32例（平均年龄53岁）正常人进行对照检查。用CT轴向扫描关节突关节，测量L3－4，L4－5，L5－S1关节突关节的角度，关节横向，关节面的深度和观察关节面形态。第二部分研究分别测量40例40岁以下和40例60岁以肯要痛患者的关节突关节角度，观察其关节。结果 退变笥滑脱患者与对照组相比，L4－5节段关节角度方向明显偏向矢状面，关节角度不对称和关节面深度比也有显著差异。第二部分2组下腰痛患者的关节突关节角度无统计学差异。结论 60岁以下的退变性腰椎滑脱患者存在着关节突关节形态异常，L4－5节段关节或矢状排列和／或同时伴有关节角不对称是腰椎早期滑脱的危险因素。     

寰椎椎弓根钉内固定通道的三维CT影像学研究

目的利用三维影像学探讨常人寰椎椎弓根钉内固定通道的解剖学基础。方法从本院PACS系统中随机选取60例头颈部CTA枕寰枢复合体无明确异常的影像学资料,进行回顾性三维CT成像。测量相关解剖学数据,以颈椎扩孔器横截面面积(3~5 mm2)为对照,归纳出3种椎弓根类型。结果 60例头颈部CTA三维图像显示寰椎及周围结构清楚,测量出寰椎椎动脉沟底部后弓外径高度男性(4.39±1.16)mm,女性(3.84±0.84)mm,小于常规螺钉直径(3.50 mm)占27.7%;在寰椎椎弓根通道分型中,Ⅰ型68侧,占56.67%,Ⅱ型25侧,占20.83%;Ⅲ型27侧,占22.50%;皮质骨面积比例随通道面积的减小而增大,在各型椎弓根通道都在80%以上。结论寰椎椎动脉沟底部后弓外径高度是制约寰椎椎弓根钉固定的重要因素,而寰椎椎弓根骨性通道的解剖结构特点则影响置钉技术的选择;设计出适应寰椎椎动脉沟底部后弓外径高度的螺钉是非常必要的。     

Variability of tropism and replicative capacity of two naturally occurring influenza A H9N2 viruses in cell cultures from different tissues

Studies carried out on cell permissivity are of great interest to understand virus replication and pathogenicity. We described the results of a comparative analysis of replication efficiency of two naturally occurring influenza A H9N2 variants isolated from poultry and wild birds, differing by only two substitutions Q226L and T384N, in the receptor-binding site of haemagglutinin and the 380 loop region of NA proteins, respectively. Considering the overall growth of both viruses, lung cultures ensured the most efficient growth of TUN12L226N384 strain with titres up to 10⁹ TCID₅₀/ml whereas small intestine culture was highly susceptible to the TUN51Q226T384 virus reaching a titre of 10⁶ TCID50/ml. The lowest replication was shown in liver cells. The addition of trypsin was essential for the replication of either virus in primary fibroblasts, but it had a marginal positive effect on virus replication in the four other culture types with maximum titres of 10⁸ TCID₅₀/ml. This means that in chicken, the proteolytic activation of the H9N2 viruses with the cleavage motif RSSR may be mediated by other endoproteases than trypsin. Further investigations should concentrate on the production of the appropriate set of viruses by a reverse genetics approach and the examination of cellular protease expression in chicken tissues. This would lead to a more complete understanding of the tropism of low-pathogenic Influenza A viruses.     

Hepatitis C infection of B lymphocytes: more tools to address pending questions

Evaluation of: Durand T, Di Liberto G, Colman H et al. Occult infection of peripheral B cells by hepatitis C variants which have low translational efficiency in cultured hepatocytes. Gut 59, 934–942 (2010).

Hepatitis C virus (HCV) infection spreads primarily via contact with infected blood and can establish a persistent infection in 80% of infected individuals, progressively causing chronic liver disease that can lead to hepatocellular carcinoma or end-stage liver disease requiring a transplant. There is no vaccine, and current treatment with interferon and ribavirin is costly, poorly tolerated and ineffective for a large proportion of patients. Technical limitations have stifled the study of HCV immunology, and hence the correlates of resolution remain elusive. HCV robustly infects hepatocytes in the liver, yet HCV RNA is often found to be associated with peripheral blood lymphocytes and extrahepatic manifestations of the disease include B-cell abnormalities. The few existing characterized viral clones that can replicate in vitro have consistently failed to infect immune cells; however, some groups have detected low levels of replication in peripheral blood cells, hinting that occult forms of infection may be possible. HCV lymphotropism remains a controversial subject that needs to be elucidated in order to identify viral reservoirs that may provide targets for therapeutic intervention. The precise interactions between HCV and immune cells need to be determined to establish if the virus has developed mechanisms to modulate immune responses. In the study by Durand et al., correlations were sought between cell tropism and mutations in the 5´ noncoding region of the HCV genome, known as the internal ribosome entry site. Key findings are discussed here, highlighting current experimental challenges that surround the topic of HCV lymphotropism.     

Effects of sequence alterations on results from genotypic tropism testing

Backgroundgeno2pheno_[coreceptor] is a bioinformatic method for genotypic tropism determination (GTD) which has been extensively validated.ObjectivesGTD can be affected by sequencing/base-calling variability and unreliable representation of minority populations in Sanger bulk sequencing. This study aims at quantifying the robustness of geno2pheno_[coreceptor] with respect to these issues. GTD with a single amplification or in triplicate (henceforth singleton/triplicate) is considered.Study DesignFrom a dataset containing 67,997HIV-1 V3 nucleotide sequences, two datasets simulating sequencing variability were created. Further two datasets were created to simulate unreliable representation of minority variants. After interpretation of all sequences with geno2pheno_[coreceptor], probabilities of change of predicted tropism were calculated.Resultsgeno2pheno_[coreceptor] tends to report reduced false-positive rates (FPRs) when sequence alterations are present. Triplicate FPRs tend to be lower than singleton FPRs, resulting in a bias towards classifying viruses as X4-capable. Alterations introduced into nucleotide sequences by simulation change singleton predicted tropism with a probability ≤ 2%. Triplicate prediction lowers this probability for predicted X4 tropism, but raises it for predicted R5 tropism ≤ 6%. Simulated limited detection of minority variants in X4 sequences resulted in unchanged predicted tropism with probability above 90% as compared to probability above 98% with triplicate FPRs.Conclusionsgeno2pheno_[coreceptor] proved to be robust when sequence alterations are present and when detectable minorities are missed by bulk sequencing. Changes in tropism prediction due to sequence alterations as well as triplicate prediction are much more likely to result in false X4-capable predictions than in false R5 predictions.     

The relationship between facet tropism and cervical disc herniation

Many studies have demonstrated the association between facet tropism and disc herniation in the lumbar spine. Some of them found that lumbar disc herniation was on the side of the more sagittal facet joint interface. However, little is understood about the association of facet tropism with disc herniation in the cervical spine. As the relationship between the facet orientation and the side of cervical disc herniation (CDH) is unclear, the purpose of this study is to investigate that relationship. Ninety-six patients with single-level CDH (C4-C5, C5-C6 or C6-C7) were included in the CDH group of this study. Another 50 age-matched and gender-matched healthy participants who accepted physical examinations were enrolled as the control group. The cervical facet angles of two sides were measured using axial computed tomography (CT). The intersection angle of the midsagittal line of the vertebra to the facet line represents the facet angle. Facet tropism was defined as the angular difference of 7º between the left and the right sides. Facet tropism angle was recorded as the absolute value of the difference of facet angles between two sides. There were 20 herniations at C4–C5 level, 50 herniations at C5–C6 level and 26 herniations at C6-C7 level. The present study showed that more cases in the CDH group had facet tropism than did those in the control group at C4-C5, C5-C6 and C6-C7 level (p = .021, p = .001, p = .015, respectively). The facet tropism angles in the CDH group were significantly bigger than those in the control group at C4-C5, C5-C6 and C6-C7 level (p = .001, p = .002, p = .028, respectively). In the CDH group, the facet angles on the herniated side were found to be significantly bigger than those on the healthy side at C4-C5, C5-C6 and C6-C7 level (p = .000, p = .000, p = .037, respectively). The findings of this present study suggest that facet tropism is associated with the disc herniation in the cervical spine. We also found that cervical disc herniates towards the side of the bigger facet angle with respect to the sagittal plane. There is a need for future studies to verify the biomechanical impact of facet tropism on CDH.