Characterization of the Ebola virus nucleoprotein-RNA complex

When Ebola virus nucleoprotein (NP) is expressed in mammalian cells, it assembles into helical structures. Here, the recombinant NP helix purified from cells expressing NP was characterized biochemically and morphologically. We found that the recombinant NP helix is associated with non-viral RNA, which is not protected from RNase digestion and that the morphology of the helix changes depending on the environmental salt concentration. The N-terminal 450 aa residues of NP are sufficient for these properties. However, digestion of the NP-associated RNA eliminates the plasticity of the helix, suggesting that this RNA is an essential structural component of the helix, binding to individual NP molecules via the N-terminal 450 aa. These findings enhance our knowledge of Ebola virus assembly and understanding of the Ebola virus life cycle.

First-line gefitinib versus first-line chemotherapy by carboplatin (CBDCA) plus paclitaxel (TXL) in non-small cell lung cancer (NSCLC) patients (pts) with EGFR mutations: A phase III study (002) by North East Japan Gefitinib Study Group

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Background: Based on our promising results of phase II studies estimating gefitinib in NSCLC pts with sensitive EGFR mutations (JCO 2006, BJC 2006), this multicenter phase III trial compared progression free survival (PFS) of first line gefitinib versus first line chemotherapy in EGFR mutation positive pts with stage IIIB/IV NSCLC. Per protocol, an analysis for safety except response, PFS and overall survival were estimated. Methods: PNA-LNA PCR clamp test, which had been developed and validated by us (Cancer Res 2005, Cancer Sci 2007), was employed to detect EGFR mutations using cytological samples or histological samples. Pts having sensitive EGFR mutations, measurable site(s), ECOG PS 0–1, age of 20–75 years, and no prior chemotherapy were randomized (1:1 ratio; balanced for institution, sex, and stage) to receive Arm A: gefitinb (250 mg/ day) orally, or Arms B: CBDCA AUC 6 and TXL 200mg/m2 in 21-day cycles until disease progression. The primary endpoint was PFS, and the sample size was calculated to be 320 in total (alpha=5%, power=80%) to confirm the superiority of Arm A (hazard ratio = 0.69). Results: From April 2006 to July 2008, 155 pts were enrolled (Arm A=80; Arm B=75). Their characteristics were well balanced between arms: median age=65 years; 64% female; 77% Stage IV; 93% adenocarcinoma, 61% non-smoker. There were several differences in toxicities between Arm A and Arm B (grade 4 neutropenia: 1% vs. 29%, grade 3–4 liver dysfunction: 24% vs. 1%, grade 3 neuropathy: 0% vs. 5%, respectively, p<0.01). But these were tolerable in both arms. Furthermore, there were no interstitial lung disease and no toxic deaths in both arms. Analyzing both arms together, preliminary response rate and PFS of the 155 pts were 53.7% and 6.5 mos, respectively. Conclusions: This is the first prospective study to compare first line gefitinib with first line chemotherapy for advanced NSCLC pts harboring EGFR mutations. Due to acceptable toxicities, the independent safety committee decided to continue this study further. At the end of 2008, 200 pts have been entered to this study, and, per protocol, an interim analysis to investigate PFS will be performed in May 2009.

No significant financial relationships to disclose.

A case of pulmonary alveolar microlithiasis with an intragenetic deletion in SLC34A2 detected by a genome-wide SNP study

A case of pulmonary alveolar microlithiasis occurring in an inbred family is presented. A genome-wide analysis of the patient's genomic DNA using a high-density single nucleotide polymorphism (SNP) array revealed a small intragenetic mutation at SLC34A2. The results suggest that the high-density SNP array has the power to identify a recessive disease gene(s) even in the analysis of only a single inbred patient.

p27 deregulation by Skp2 overexpression induced by the JAK2V617 mutation

Janus kinase 2 (JAK2) V617F mutation has been regarded as the major cause of myeloproliferative disorders (MPD). However, the mechanisms of abnormal cell growth by JAK2V617F have not been elucidated. In this study, cell cycle regulatory protein expression was analyzed using JAK2V617F-Ba/F3 and mock-Ba/F3. JAK2V617F-Ba/F3, but not mock-Ba/F3, showed IL-3 independent cell growth and constitutive STATs activation. Deregulation of p27(Kip1), the cell cycle regulator at the G1 to S transition, was observed in JAK2V617F-Ba/F3 but not in mock-control. p27(Kip1) deregulation was not due to p27(Kip1) mRNA level but due to high Skp2 expression, a subunit of ubiquitin E3 ligase, through the STAT binding in the Skp2 promoter. Like JAK2V617F overexpression, constitutively active STAT5 or STAT3 induced aberrant p27(Kip1) expression of Ba/F3 cells. Similar findings were observed in BCR/ABL-transfected Ba/F3. Our results elucidate the regulatory mechanism by which JAK2V617F modulates Skp2 gene expression through the STAT transcription factors.

A single residue in the 126-kDa protein of pepper mild mottle virus controls the severity of symptoms on infected green bell pepper plants

Infectious cDNA clones originally derived from a mild strain of Pepper mild mottle virus were constructed by replacing residue 649, a critical point for attenuation of this virus, with all possible amino acids. All clones were infectious to pepper plants and induced a variety of symptoms, including no visible symptoms. The results of this study showed that a single amino acid mutation at residue 649 could control the function of the 126- and 183-kDa proteins, replicases with multiple roles in the life cycle of this virus.

[Integrated coronary artery bypass strategy prevents urgent pump conversion during off-pump coronary artery bypass grafting]

Urgent pump conversion during off-pump coronary artery bypass (OPCAB) results in high morbidity and mortality. We retrospectively evaluated if the peri-operative integrated strategy prevents this lethal event in our 400 consecutive OPCAB operations. The patients with preoperative cardiogenic shock and/or ventricular arrhythmias underwent on-pump coronary artery bypass grafting (CABG). All other patients (99% of total CABG) were scheduled to undergo OPCAB (n=400). Prophylactic intraaortic balloon pumping (IABP) was applied to the patients with critical (>95%) left main trunk stenosis or low (<0.35) left ventricular ejection fraction. All the patients received the deep pericardial suture, apex-traction device, suction-type stabilizer, test-clamp of target coronary arteries by micro bulldog clamp, and intra-coronary shunts. Intra-operative IABP was applied in the case of sustained ST-segment change and/or elevated pulmonary artery pressure. Pump conversion was indicated for the patients with ventricular fibrillation and/or cardiogenic shock. Two patients (0.5%) had pump conversion due to ventricular arrhythmia and sustained hypotension, respectively. These pump conversion did not result in hospital mortality. Three hospital deaths (0.7%) occurred due to non-cardiac causes. The integrated strategy using prophylactic or intra-operative IABP in OPCAB produce a low pump conversion rate even during an early period of surgeon's learning curve.

Extent of hepatitis E virus elimination is affected by stabilizers present in plasma products and pore size of nanofilters

BACKGROUND AND OBJECTIVE

To investigate the physico-chemical properties of hepatitis E virus (HEV) with regard to inactivation/removal, we have studied four isolates with respect to sensitivity to heat during liquid/dry-heating as well as removal by nanofiltration.

MATERIALS AND METHODS

Hepatitis E virus in an albumin solution or phosphate-buffered saline (PBS) was liquid-heated at 60 degrees C for a preset time. HEV in a freeze-dried fibrinogen containing stabilizers was also dry-heated at 60 or 80 degrees C for a preset time. In addition, to clarify the removal of HEV, the purified virus in PBS was filtered using several types of virus-removal filter (nanofilters) that have different pore sizes. HEV infectivity or genome equivalents before and after the treatments were assayed by a semiquantitative cell-based infectivity assay or quantitative polymerase chain reaction assay, respectively.

RESULTS

Hepatitis E virus isolates in albumin solutions were inactivated slowly at 60 degrees C for 5 h and the resultant log reduction factor (LRF) was from 1.0 to > or = 2.2, whereas the virus in PBS was inactivated quickly to below the detection limit and the LRF was > or = 2.4 to > or = 3.7. The virus in a freeze dried fibrinogen containing trisodium citrate dihydrate and l-arginine hydrochloride as stabilizers was inactivated slowly and the LRF was 2.0 and 3.0, respectively, of the 72 h at 60 degrees C, but inactivated to below the detection limit within 24 h at 80 degrees C with an LRF of > or = 4.0. The virus in PBS was also confirmed as to be approximately 35 nm in diameter by nanofiltration. These results are useful for evaluating viral safety against HEV contamination in blood products.

CONCLUSION

The sensitivity of HEV to heat was shown to vary greatly depending on the heating conditions. On the other hand, the HEV particles were completely removed using 20-nm nanofilters. However, each inactivation/removal step should be carefully evaluated with respect to the HEV inactivation/removal capacity, which may be influenced by processing conditions such as the stabilizers used for blood products.

Interferon-beta augments eosinophil adhesion-inducing activity of endothelial cells

Viral infections induce exacerbations of asthma. One of the earliest host responses to viral infections is the production of innate cytokines including type I interferons (IFNs), such as IFN-beta, which may act to modify airway inflammation. The objective of the present study was to investigate whether IFN-beta modifies the eosinophil adhesion-inducing activity of endothelial cells. Human umbilical vein endothelial cells (HUVECs) were stimulated with IFN-beta for 24 h in the presence or absence of tumour necrosis factor (TNF)-alpha. Eosinophils were isolated from the peripheral blood of healthy volunteers. The ability of the IFN-beta-stimulated HUVEC monolayers to induce eosinophil adhesion was assessed according to the eosinophil peroxidase assay. Eosinophil adhesion to HUVECs was significantly augmented by IFN-beta in the presence of TNF-alpha but not in its absence. The augmented adhesion was inhibited by anti-alpha(4) integrin monoclonal antibody (mAb) or anti-beta(2) integrin mAb. IFN-beta significantly enhanced the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 on HUVECs in the presence of TNF-alpha. Interferon-beta can augment the adhesiveness of endothelial cells to eosinophils, mainly through the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. This action of interferon-beta may contribute to the intensification of airway inflammation in asthma that is associated with exacerbations induced by viral infections.

Retention of Rice dwarf virus by Descendants of Pairs of Viruliferous Vector Insects After Rearing for 6 Years

ABSTRACT Rice dwarf virus (RDV) is characterized by its unusual ability to multiply in both plants and leafhopper vector insects and by its transovarial mode of transmission. Colonies of Nephotettix cincticeps, derived originally from pairs of leafhoppers infected with an ordinary strain of RDV, were maintained for 6 years in the laboratory and were found, at the end of this time, still to harbor RDV. Moreover, the isolate of RDV, designated RDV-I, obtained from these colonies retained the ability to infect rice plants. When we raised leafhoppers separately from eggs that had been placed individually on pieces of water-soaked filter paper and reared them in the presence of healthy rice seedlings, we found that all of these leafhoppers harbored RDV. This observation suggested that RDV-I had been maintained in the leafhoppers by transovarial transmission. Two further observations, namely, the low rate of acquisition of RDV by virus-free insect nymphs on symptomless plants on which viruliferous insects had been reared, and the fact that only 2 to 5% of plants had symptoms when rice seedlings were inoculated via RDV-I-viruliferous insects, confirmed that the maintenance of RDV-I by any other mode of transmission through plants and insects was unlikely. This efficient and long-term maintenance of RDV in a population of viruliferous insects might explain the prolonged duration of rice dwarf disease in the field, once there has been a serious outbreak.

Molecular analysis of the genome segments S1, S4, S6, S7 and S12 of a Rice gall dwarf virus isolate from Thailand; completion of the genomic sequence

The complete nucleotide sequences of the double-stranded RNA segments S1, S4, S6, S7 and S12 of the genome of a Rice gall dwarf virus (RGDV) isolate from Thailand were determined. The segments consisted of 4505, 2622, 1648, 1652 and 853 nucleotides, encoding putative proteins of 1458, 725, 489, 511 and 206 amino acids with molecular masses of approximately 166, 80, 53, 59 and 24 kDa, respectively. Homology searches indicated that each of the putative proteins has a counterpart in isolates of Rice dwarf virus (RDV) and Wound tumor virus, two other species in the genus Phytoreovirus. However, no similarities were found to other registered sequences, including those of other viruses that belong to the family Reoviridae. The identities between homologous structural proteins of RGDV and RDV ranged from 34 to 51% and were thus higher than those between homologous non-structural proteins of RGDV and RDV (16-37%). Among the nonstructural proteins, the highest amino acid sequence identity (37%) was observed for RGDV Pns11 and RDV Pns10, a constituent of tubular inclusions. This observation suggests that a specific amino acid backbone might be required for maintaining not only the three-dimensional structure of virions but also that of inclusions. The entire sequence of the RGDV genome is now available.