Molecular analyses of the hemagglutinin genes of H5 influenza viruses: origin of a virulent turkey strain

Comparative sequence analysis of the hemagglutinin (HA) genes of a highly virulent H5N8 virus isolated from turkeys in Ireland in 1983 and a virus of the same subtype detected simultaneously in healthy ducks showed only four amino acid differences between these strains. Partial sequencing of six of the other genes and antigenic similarity of the neuraminidases established the overall genetic similarity of these two viruses. Comparison of the complete sequence of two H5 gene sequences and partial sequences of other virulent and avirulent H5 viruses provides evidence for at least two different lineages of H5 influenza virus in the world, one in Europe and the other in North America, with virulent and avirulent members in each group. In vivo studies in domestic ducks showed that all of the H5 viruses that are virulent in chickens and turkeys replicate in the internal organs of ducks but did not produce any disease signs. Additionally, both viruses isolated from turkeys and ducks in Ireland were detected in the blood. These studies provide the first conclusive evidence for the possibility that fully virulent influenza viruses in domestic poultry can arise directly from viruses in wild aquatic birds. Studies on the cleavability of the HA of virulent and avirulent H5 viruses showed that the principles established for H7 viruses (F. X. Bosch, M. Orlich, H. D. Klenk, and R. Rott, 1979, Virology 95, 197-207; F. X. Bosch, W. Garten, H. D. Klenk, and R. Rott, 1981, Virology 113, 725-735) also apply to the H5 subtype. These are (1) only the HAs of virulent influenza viruses were cleaved in tissue culture in the absence of trypsin and (2) virulent H5 influenza viruses contain a series of basic amino acids at the cleavage site of the HA, whereas avirulent strains contain only a single arginine with the exception of the avirulent Chicken/Pennsylvania virus. Thus, a series of basic amino acids at the cleavage site probably forms a recognition site for the enzyme(s) responsible for cleavage.     

Virulent influenza A viruses induce apoptosis in chickens

Virulent avian influenza A viruses produce lethal disease in chickens. Since cell death can be caused by either necrosis or apoptosis, we investigated the types of cell death that occur in natural hosts, chickens, infected with virulent avian viruses. Using biochemical methods, we demonstrate that virulent avian influenza viruses induce apoptosis of vascular endothelial cells in liver, kidney, and brain. Viral antigens were also detected in these organs, suggesting that viral replication induces apoptosis in infected chickens. These results indicate that apoptosis does occur in virulent avian influenza virus infection in a natural host, and may contribute to the lethality of the virus.     

A case of primary malignant melanoma of the esophagus with long-term survival

Primary malignant melanoma of the esophagus is uncommon, and its prognosis is poor compared to that of cutaneous malignant melanoma. Here we describe a case of primary malignant melanoma of the esophagus with a long-term survival. A 52-year-old woman received an upper gastrointestinal endoscopy and an upper gastrointestinal series for a dull back pain and dysphagia. A pigmented polypoid tumor in the esophagus was discovered and diagnosed pathologically as a malignant melanoma on the biopsied specimen. After effective chemotherapy with cisplatin (CDDP), the patient underwent surgical operation. A subtotal esophagectomy with three-field lymph node dissection was performed through a right thoracotomy. No distant metastasis including liver and lung was found, and histopathological examination revealed no lymph node metastasis. Postoperatively, six courses of chemotherapy with CDDP were performed. The patient has been alive without any problems for more than 11 years postoperatively.     

Downregulation of cytochrome P450scc as an initial adverse effect of adult exposure to diethylstilbestrol on testicular steroidogenesis

Reproductive toxicities and endocrine disruptions caused by chemicals in adult males are still poorly understood. It is our objectives to understand further details of the initial adverse effects leading severe testicular toxicities of a pharmaceutical endocrine disruptor, diethylstilbestrol (DES). Downregulations of both testicular regulatory proteins, such as the steroidogenic acute regulatory protein (StAR) and the peripheral benzodiazepine receptor (PBR), which play important roles in the transport of cholesterol into the mitochondria, and cytochrome P450 mediating the cholesterol side chain cleavage reaction (P450scc), were observed in the rat orally administered DES (340 μg/kg/2 days) for 2 weeks. We found that after only 1 week treatment with DES, the blood and testicular testosterone (TS) levels were drastically decreased without abnormalities of the StAR and PBR; however, the protein and mRNA levels of P450scc were diminished. Decrease in the conversion rate of cholesterol to pregnenolone was delayed in the in vitro assay using the testicular mitochondrial fraction from the rat treated with DES for 1 week. When the precursors in TS biosynthesis containing the testis were identified and determined by liquid chromatography‐mass spectrometry analysis, decreased levels of all precursors except cholesterol were observed. In conclusion, suppressed cytochrome P450scc expression in adult male rat was identified as an initial target of DES in testicular steroidogenesis disorder leading reproductive toxicities. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1452–1459, 2014.     

Two patients treated with pegylated interferon/ribavirin/telaprevir triple therapy for recurrent hepatitis C after living donor liver transplantation

It is difficult to use protease inhibitors in patients with recurrent hepatitis C virus (HCV) infection after liver transplantation (LT) due to interaction with immunosuppressive drugs. We report our experience with two patients treated with telaprevir (TVR) combined with pegylated interferon/ribavirin (PEG IFN/RBV) for recurrent HCV genotype 1 infection after LT. The first was a 63‐year‐old man with HCV‐related liver cirrhosis, who failed to respond to IFN‐β plus RBV after LT. Treatment was switched to PEG IFN‐α‐2b plus RBV and TVR was started. The donor had TT genotype of interleukin (IL)‐28 single nucleotide polymorphisms (SNP) (rs8099917). The recipient had TT genotype of IL‐28 SNP (rs8099917). Completion of 12‐week triple therapy was followed by PEG IFN‐α‐2b plus RBV for 36 weeks. Finally, he had sustained viral response. The second was a 70‐year‐old woman with HCV‐related liver cirrhosis and hepatocellular carcinoma. She failed to respond to PEG IFN‐α‐2b plus RBV after LT, and was subsequently switched to PEG IFN‐α‐2b/RBV/TVR. Genotype analysis showed TG genotype of IL‐28 SNP for the donor, and TT genotype of IL‐28 SNP for the recipient. Serum HCV RNA titer decreased below the detection limit at 5 weeks. However, triple therapy was withdrawn at 11 weeks due to general fatigue, which resulted in HCV RNA rebound 4 weeks later. Both patients were treated with cyclosporin, starting with a small dose to avoid interactions with TVR. TVR is a potentially suitable agent for LT recipients who do not respond to PEG IFN‐α‐2b plus RBV after LT.     

The mechanism of Axl-mediated Ebola virus infection

We previously reported that expression of the receptor-type tyrosine kinase Axl, which regulates cell survival and activation, enhances both pseudotype and live Ebola virus (EBOV) infection. To clarify the mechanistic basis of this enhancement, we created a series of Axl mutants and identified amino acids/domains necessary for this function, by using a pseudotype virus carrying the EBOV glycoprotein (GP). Analyses of the Axl mutants showed the importance of extracellular and intracellular regions for Axl functions, including ligand binding and signal transduction, in EBOV GP-mediated infection. These data suggest that EBOV uses the physiological functions of Axl to enter cells.     

Generation of velogenic Newcastle disease viruses from a nonpathogenic waterfowl isolate by passaging in chickens

A benign Newcastle disease virus (NDV) recently became highly virulent during replication in domestic chickens. It is still unclear whether NDVs circulating among wild waterfowl also have the potential to become highly pathogenic (velogenic) in chickens. To demonstrate experimentally the generation of velogenic NDV from a nonpathogenic waterfowl isolate, we passaged an avirulent goose isolate in chickens. After nine consecutive passages by air-sac inoculation, followed by five passages in chick brain, the virus became highly virulent in chickens, producing a 100% mortality rate, and demonstrating typical velogenic properties in pathogenicity tests. Sequence analysis at the fusion protein cleavage site showed that the original isolate contained the typical avirulent type sequence, E-R-Q-E-R/L, which progressed incrementally to a typical virulent type, K-R-Q-K-R/F, during repeated passage in chickens. These results demonstrate that avirulent viruses, maintained in wild waterfowl in nature and bearing the consensus avirulent type sequence, have the potential to become velogenic after transmission to and circulation in chicken populations. The results also suggest that chickens provide a mechanism for the selection of virulent viruses from an avirulent background.     

Intra‐arterial 5‐fluorouracil/interferon combination therapy for hepatocellular carcinoma with portal vein tumor thrombosis and extrahepatic metastases

Background and Aims: We investigated the efficacy of intra‐arterial 5‐fluorouracil (5‐FU) and systemic interferon (IFN)‐α (5‐FU‐IFN) in the treatment of hepatocellular carcinoma (HCC) with portal vein tumor thrombosis in the first branch or trunk (Vp3/4) and extrahepatic metastases. Methods: We examined 17 HCC patients with Vp3/4 and extrahepatic metastases (meta group) and 31 HCC patients with Vp3/4 (non‐meta group). Baseline intrahepatic tumor factors and the hepatic reserve were similar between groups. The extrahepatic metastases of the meta group were not considered prognostic factors. Following the administration of 5‐FU/IFN to all patients, we compared the survival rates, response, time to progression (TTP), and safety between groups. Results: For intrahepatic HCC, complete response, partial response, stable disease, progressive disease, and drop out were observed in no (0%), one (6%), seven (41%), nine (53%), and no (0%) patients of the meta group, and in five (16%), seven (23%), 13 (42%), five (16%) and one (3%) patient of the non‐meta group, respectively. The response rate was significantly lower in the meta group (6% vs 39%, P = 0.018). The median TTP of intrahepatic HCC and the median survival time were significantly shorter in the meta group than in the non‐meta group (1.6 vs 6.3 months, P = 0.0001, and 3.9 months vs 10.5 months, P < 0.0001, respectively). The multivariate analysis showed that the absence of extrahepatic metastases was a significant and independent determinant of both TTP of intrahepatic HCC (P < 0.001) and overall survival (P < 0.001). No patient died of extrahepatic HCC‐related disease. Conclusions: The efficacy of 5‐FU/IFN for advanced HCC with Vp3/4 and extrahepatic metastases was markedly limited.