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M Mase

Publications and source records attributed to M Mase.

At least 19 recordsLinked to original sources
PubMed2006

Characterization of H9N2 influenza A viruses isolated from chicken products imported into Japan from China.

We characterized eleven H9N2 influenza A viruses isolated from chicken products imported from China. Genetically they were classified into six distinct genotypes, including five already known genotypes and one novel genotype. This suggested that such multiple genotypes of the H9N2 virus have possibly already become widespread and endemic in China. Two isolates have amino-acid substitutions that confer resistance to amantadine in the M2 region, and this supported the evidence that this mutation might be a result of the wide application of amantadine for avian influenza treatment in China. These findings emphasize the importance of surveillance for avian influenza virus in this region, and of quarantining imported chicken products as potential sources for the introduction of influenza virus.

Animals↗
PubMed2006

Pathology of fatal highly pathogenic H5N1 avian influenza virus infection in large-billed crows (Corvus macrorhynchos) during the 2004 outbreak in Japan.

Highly pathogenic H5N1 avian influenza viruses were isolated in 9 large-billed crows that died in Kyoto and Osaka prefectures in Japan from March to April in 2004. We studied 3 of the 9 crows using standard histologic methods, immunohistochemistry, and virus isolation. The most prominent lesions were gross patchy areas of reddish discoloration in the pancreas. The consistent histologic lesions included severe multifocal necrotizing pancreatitis, focal degeneration and necrosis of neuron and glial cells in the central nervous system, and focal degeneration of cardiac myocytes. All of these tissues contained immunohistochemically positive influenza viral antigens. The virus was isolated from the brain, lung, heart, liver, spleen, and kidney of the crows examined. Thus we concluded that highly pathogenic avian influenza virus was associated with clinical disease, severe pathologic changes, and death in the 3 crows.

Animals↗
PubMed2005

Rapid detection and differentiation of Newcastle disease virus by real-time PCR with melting-curve analysis.

In order to rapidly detect and differentiate Newcastle disease virus (NDV) isolates, a method based on real-time PCR SYBR Green I melting-curve analysis of the fusion (F) protein gene was developed. The detection limit of real-time PCR was 9 x 10(2) plasmid copies and was 100 times more sensitive than conventional PCR. Thirty eight reference NDV strains were rapidly identified by their distinctive melting temperatures (T(m)s): 89.23 +/- 0.27 degrees C for velogenic strains, 90.17 +/- 0.35 degrees C for pigeon mesogenic strains, 91.25 +/- 0.14 degrees C for two lentogenic strains (B1 and Ishii). No amplification was detected from unrelated RNA samples by this method. This real-time PCR directly detected NDV from infected tissues and eliminated the gel electrophoretic step for analyzing PCR product using ethidium bromide. The total time for a PCR run was less than 1 hour. The results obtained in this study showed that the real-time PCR presented here is a good screening test for the identification of NDV.

Animals↗
PubMed2005

Non-invasive measurement of intracranial compliance using cine MRI in normal pressure hydrocephalus.

The aim of this study is to clarify biophysics of normal pressure hydrocephalus (NPH) based on non-invasive intracranial compliance measurement using magnetic resonance imaging (MRI). Patients with NPH after subarachnoid hemorrhage (NPH group, n = 5), brain atrophy or asymptomatic ventricular dilation (VD group, n = 5), and healthy volunteers (control group, n = 12) were included in this study. Net blood flow (bilateral internal carotid and vertebral arteries, and jugular veins) and cerebrospinal fluid (CSF) flow in subarachnoid space at the C2 level of cervical vertebra were measured using phase-contrast cine MRI. CSF pressure gradient and intracranial volume changes during a cardiac cycle were calculated based on Alperin's method. Compliance index (Ci = delta V/delta P) was obtained from the maximum pressure gradient and volume changes. Pressure volume response (PVR) was measured in the NPH group during a shunt operation. Ci in the NPH group was the lowest among the three studies groups. No difference was found between the control and VD groups. There was a linear correlation between Ci and PVR. In conclusion, intracranial compliance can be determined by cine MRI non-invasively. It is well known that NPH has relatively low intracranial compliance, this non-invasive method can be used for the diagnosis of NPH.

Brain↗
PubMed2005

Control of an outbreak of highly pathogenic avian influenza, caused by the virus sub-type H5N1, in Japan in 2004.

An outbreak of highly pathogenic avian influenza (HPAI), caused by the virus sub-type H5N1, occurred at four premises in three prefectures in Japan during January and March 2004. As a result, 274,654 poultry died or were slaughtered. This was the first outbreak of HPAI in Japan since 1925. (The earlier outbreak was caused by H7N7.) The disease was successfully eradicated within three-and-a-half months, following an eradication campaign that included depopulating the affected premises, implementing movement controls and intensive surveillance. Control measures were conducted in accordance with the National Manual of HPAI Control. However, during the eradication campaign, some key issues arose, such as delays in notification by the affected farmers. As a result of these experiences, the relevant laws and HPAI Control Manual have been appropriately revised.

Animals↗
PubMed2004

Molecular characterization of the nucleocapsid protein gene of Newcastle disease virus strains in Japan and development of a restriction enzyme-based rapid identifying method.

Nucleocapsid protein (NP) gene of Newcastle disease virus (NDV) strains mainly isolated in Japan from 1930 to 2001 was genetically characterized. By deduced amino acid sequence comparison, the N-terminal region (from 1 to 401 residues) of the NP protein was found to be highly conserved, while the C-terminal region was highly variable among the NDV isolates. A phylogenetic tree construct based on the nucleotide sequence of the complete NP gene revealed that the old (prior to 1970s) and the new (after 1980s) isolates could be classified into two major different groups, i.e., a group comprising virulent strains, and another group composed of avirulent strains. By restriction enzyme analysis using Pst I, none of the virulent strains were cleaved, while avirulent strains were cleaved. The results may be useful for simple primary screening test for differentiating NDV isolates.

Amino Acid Sequence↗
PubMed2004

Phylogenetic analysis of avian infectious bronchitis virus strains isolated in Japan.

To define the origin and evolution of recent avian infectious bronchitis virus (IBV) in Japan, a genetic analysis was performed. By phylogenetic analysis based on the S1 gene including the sequence of the hypervariable regions, IBV isolates in Japan were classified into five genetic groups, which included two already-known groups (Mass and Gray). Among them, three major genetic groups were associated with the recent outbreaks of IB in Japan. One group is indigenous to Japan and could not be placed within the known existing groups in other countries. The remaining two groups, which have emerged recently, are related to isolates in China and Taiwan.

Amino Acid Sequence↗
PubMed2002

Complete, long-lasting protection against lethal infectious bursal disease virus challenge by a single vaccination with an avian herpesvirus vector expressing VP2 antigens.

Marek's disease herpesvirus is a vaccine vector of great promise for chickens; however, complete protection against foreign infectious diseases has not been achieved. In this study, two herpesvirus of turkey recombinants (rHVTs) expressing large amounts of infectious bursal disease virus (IBDV) VP2 antigen under the control of a human cytomegalovirus (CMV) promoter or CMV/beta-actin chimera promoter (Pec promoter) (rHVT-cmvVP2 and rHVT-pecVP2) were constructed. rHVT-pecVP2, which expressed the VP2 antigen approximately four times more than did rHVT-cmvVP2 in vitro, induced complete protection against a lethal IBDV challenge in chickens, whereas rHVT-cmvVP2 induced 58% protection. All of the chickens vaccinated with rHVT-pecVP2 had a protective level of antibodies to the VP2 antigen at the time of challenge, whereas only 42 and 67% of chickens vaccinated with rHVT-cmvVP2 or the conventional live IBDV vaccine, respectively, had the antibodies. The antibody level of chickens vaccinated with rHVT-pecVP2 increased for 16 weeks, and the peak antibody level persisted throughout the experiment. The serum antibody titer at 30 weeks of age was about 20 or 65 times higher than that of chickens vaccinated with rHVT-cmvVP2 or the conventional live vaccine, respectively. rHVT-pecVP2, isolated consistently for 30 weeks from the vaccinated chickens, expressed the VP2 antigen after cultivation, and neither nucleotide mutations nor deletion in the VP2 gene was found. These results demonstrate that the amount of VP2 antigen expressed in the HVT vector was correlated with the vaccine efficacy against lethal IBDV challenge, and complete protective immunity that is likely to persist for the life of the chickens was induced.

Animals↗
PubMed2002

Pancreatic necrosis and ventricular erosion in adenovirus-associated hydropericardium syndrome of broilers.

Seven 19-day-old broiler chickens affected with hydropericardium syndrome (HPS) with pancreatic necrosis and gizzard erosions were investigated pathologically and virologically. Mortality increased after 13 days of age in a flock on a broiler farm. The mortality rate of the flock reached 10% by 19 days of age. Macroscopically, the chickens had hydropericardium (the characteristic gross change of HPS), pinpoint white foci in the pancreas, and ventricular erosions. Histologically, the chickens had multifocal hepatic necrosis with intranuclear inclusions in hepatocytes, a marked increase of macrophages in the spleen and lung, mild epicardial edema, multifocal necrosis of pancreatic acinar cells with intranuclear inclusions, focal necrosis of the ventricular koilin layer, and degeneration of the ventricular glandular epithelium with intranuclear inclusions. Immunohistochemically, intranuclear inclusions in the liver, pancreas, and ventriculi were stained positively against group I avian adenovirus (GIAAV) antigens. Ultrastructurally, 67-nm diameter viral particles were present in intranuclear inclusions. Virologically, serotype 4 of GIAAV was isolated from the liver, heart, and kidney of affected chickens. The pathologic changes of the present cases differ from previous cases of HPS; therefore, the present strain of GIAAV may have different pathogenicity for chickens than the previous virus strain of HPS.

Adenoviridae Infections↗
PubMed2001

Alterations in the expression of the AQP family in cultured rat astrocytes during hypoxia and reoxygenation.

Aquaporins (AQPs) are a family of water-selective transporting proteins with homology to the major intrinsic protein (MIP) of lens [Cell 39 (1984) 49], that increase plasma membrane water permeability in secretory and absorptive cells. In the central nervous system (CNS), we detected the transcripts of AQP3, 5 and 8 in addition to the previously reported transcripts of AQP4 and 9 in astrocytes, of AQP3, 5 and 8 in neurons, of AQP8 in oligodendrocytes, and none of them in microglia using RNase protection assay and the reverse transcription-polymerase chain reaction (RT-PCR). Hypoxia evoked a marked decrease in the expression levels of AQP4, 5 and 9, but not of AQP3 and 8 mRNAs, and in astrocytes in vitro subsequent reoxygenation elicited the restoration of the expression of AQP4 and 9 to their basal levels. Interestingly, AQP5 showed a transient up-regulation (about 3-fold) and subsequent down-regulation of its expression within 20 h of reoxygenation after hypoxia. The changes in the profiles of AQP expression during hypoxia and reoxygenation were also observed by Western blot analysis. These results suggest that AQP5 may be one of the candidates for inducing the intracranial edema in the CNS after ischemia injury.

Animals↗
PubMed2001

Regulation of aquaporin-4 expression in astrocytes.

Aquaporin-4 (AQP4), a mercury-insensitive water channel protein, is abundant in the central nervous system and is localized in astrocytes and ependymal cells. AQP4 is speculated to maintain the homeostasis of intracellular and extracellular water in the brain, but little is known about the mechanism of induction of its expression. To investigate the expressional regulation of AQP4, we analyzed changes in its expression during chemically induced differentiation of embryonal carcinoma cells (P19) to neuronal and astrocytic cells, and during the cell cycle of glioma cells. After exposure to retinoic acid for 4 days AQP4 mRNA expression started at the initiation of astrocytic differentiation of P19 cells at 6 days, and increased markedly by 21 days. AQP4 expression was parallel to that of GFAP, a marker intermediate filament of astrocytes. In glioma cell lines, AQP4 mRNA was not detected in the growing phase, but was induced when the cell cycle was arrested at G0/G1 by transient expression of p21. Although quiescent astrocytes in the G0/G1-phase cultured under the serum-free condition exhibited a high expression of AQP4, serum supplement moved them to the S-phase and markedly decreased the AQP expression. These results suggest that AQP4 expression may be induced not only at the initiation of astrocytic differentiation of neural stem cells, but also at the G0/G1-phase during the cell cycle of astrocytes.

Animals↗
PubMed2001

Surgical treatment of chronic subdural hematoma based on intrahematomal membrane structure on MRI.

BACKGROUND: To determine the optimal surgical management of chronic subdural hematoma (CSDH), we assessed which operative procedure, burr holes or small craniotomy, was more effective on 49 consecutive patients. METHOD: We retrospectively classified all cases into two groups according to the intrahematomal membrane structure of CSDH on T2*-weighted magnetic resonance (MR) imaging. The first group, labeled type B, included hematomas which had no intrahematomal membrane and/or were monolayer multilobule. The second group, labeled type C, consisted of hematomas which were divided into multiple layers by the intrahematomal membrane. FINDINGS: The outcome of type C patients treated with burr holes was significantly inferior to that of those who underwent a small craniotomy in terms of the relative outcome of neurological grading. re-operation ratio, and postoperative hospital stay (p < 0.05). Type C hematomas treated with burr holes also had inferior outcome compared with a small craniotomy in terms of the duration of hematoma until disappearance on postoperative CT (p < 0.05). INTERPRETATION: We concluded that a considerable number of cases appeared to need craniotomy and resection of intrahematomal membrane for complete recovery in CSDH, and that T2*-weighted MR imaging could be used as a basis for selecting the operative procedure for CSDH.

Adult↗
PubMed2001

Identification of a genetic determinant of pathogenicity in chicken anaemia virus.

The molecular basis of pathogenicity of the chicken anaemia virus (CAV) needs to be clarified in order to develop a safe, live virus vaccine. In this study, several high- and low-pathogenic infectious DNA clones were obtained from field virus samples after 12 or 38 passages in MDCC-MSB1 cells. The high-pathogenic clones induced a low haematocrit, low weight gain and high mortality. Nucleotide sequence analyses identified one amino acid, at residue 394 of the VP1 capsid protein, as a major determinant of pathogenicity. To determine the role of this amino acid in pathogenicity, chimeric infectious DNA clones and point-mutated clones were used for chicken pathogenicity tests. These analyses clearly demonstrated that residue 394 of VP1 was crucial for the pathogenicity of CAV; all of the cloned viruses with glutamine at this position were highly pathogenic, whereas those with histidine had low pathogenicity. Low-pathogenic CAV, based on an infectious DNA clone, is a candidate for a genetically homogeneous and stable CAV live vaccine.

Amino Acid Sequence↗
PubMed2001

Imported parakeets harbor H9N2 influenza A viruses that are genetically closely related to those transmitted to humans in Hong Kong.

In 1997 and 1998, H9N2 influenza A viruses were isolated from the respiratory organs of Indian ring-necked parakeets (Psittacula Krameri manillensis) that had been imported from Pakistan to Japan. The two isolates were closely related to each other (>99% as determined by nucleotide analysis of eight RNA segments), indicating that H9N2 viruses of the same lineage were maintained in these birds for at least 1 year. The hemagglutinins and neuraminidases of both isolates showed >97% nucleotide identity with those of H9N2 viruses isolated from humans in Hong Kong in 1999, while the six genes encoding internal proteins were >99% identical to the corresponding genes of H5N1 viruses recovered during the 1997 outbreak in Hong Kong. These results suggest that the H9N2 parakeet viruses originating in Pakistan share an immediate ancestor with the H9N2 human viruses. Thus, influenza A viruses with the potential to be transmitted directly to humans may be circulating in captive birds worldwide.

Amino Acid Sequence↗
PubMed2001

Characteristics of acoustic noise in echo-planar imaging.

Characteristics of the acoustic noise generated by magnetic resonance imagers of different systems and performance levels were studied when operating in echo-planar imaging (EPI) sequence. Continuous equivalent A-weighted sound pressure levels (Leq) and peak impulse sound pressure levels (Lpeak) during EPI were measured in 12 clinical super-conducting MRI systems (0.5-1.5 T). Sound pressure levels and frequency spectra of EPI were compared with those of nine different pulse sequences. EPI sound pressure levels differed among institutions (Leq = 94.2 +/- 2.7 dBA. Lpeak = 109.1 +/- 3.5 dB), but these were within permissible noise exposure levels. Sound pressure levels during EPI were not significantly different from those during other pulse sequences. However, compared to other pulse sequences. EPI had a significantly greater proportion of acoustic noise in the high octave-frequency band. Single-shot EPI had relatively higher frequency noise and greater Leq than multishot EPI, but the difference in Leq decreased when the number of slices in multishot EPI was increased.

Echo-Planar Imaging↗
PubMed2000

Dual-viral vector approach induced strong and long-lasting protective immunity against very virulent infectious bursal disease virus.

To induce strong protective immunity against very virulent infectious bursal disease virus (vvIBDV) in chickens, two viral vector systems, Marek's disease and Fowlpox viruses expressing the vvIBDV host-protective antigen VP2 (rMDV, rFPV), were used. Most of chickens vaccinated with the rFPV or rMDV alone, or vaccinated simultaneously with both at their hatch (rMDV-rFPV(1d)), were protected against developing clinical signs and mortality; however, only zero to 14% of the chickens were protected against gross lesions. In contrast, gross lesions were protected in 67% of chickens vaccinated primarily with the rMDV followed by boosting with the rFPV 2 weeks later (rMDV-rFPV(14d)). Protection against the severe histopathological lesions of rFPV, rMDV, rMDV-rFPV(1d), and rMDV-rFPV(14d) vaccine groups were 33, 42, 53, and 73%, respectively. Geometric mean antibody titers to VP2 of chickens vaccinated with the rFPV, rMDV, rMDV-rFPV(1d), and rMDV-rFPV(14d) before the challenge were 110, 202, 254, and 611, respectively. Persistent infection of the rMDV in chickens after the booster vaccination with rFPV was suggested by detection of the rMDV genes from peripheral blood lymphocyte DNA at 28 weeks of age. These results indicate that the dual-viral vector approach is useful for quickly and safely inducing strong and long-lasting protective immunity against vvIBDV in chickens.

Animals↗