Biomedical subjects

M Nishio

Publications and source records attributed to M Nishio.

At least 253 records · Page 14Linked to original sources

PubMed1991

Transcripts of simian virus 41 (SV41) matrix gene are exclusively dicistronic with the fusion gene which is also transcribed as a monocistron.

The complete nucleotide sequences of the matrix (M) and fusion (F) genes of simian virus 41 (SV41) were determined. Deduced amino acid sequences confirmed the close relationship of SV41 with human parainfluenza type 2 virus (PIV2). Analyses of noncoding regions between the F and the hemagglutinin-neuraminidase (HN) genes suggested the absence of the small hydrophobic gene, which is present between the F and the HN genes of simian virus 5 and mumps virus. It was striking that there was no apparent consensus gene end sequence between the M and the F genes and that the M gene was transcribed exclusively as a dicistron with the F gene. The number of monocistronic transcripts of the F gene was approximately half that of the dicistronic transcripts. However, the F protein of SV41 seemed to be efficiently translated, since viral multiplication and fusion from within were as efficient as in PIV2. These results suggest that the lack of a consensus gene end sequence resulted in the readthrough of viral RNA polymerases between the M and the F genes and that the initiation of F gene transcription could occur by newly entered polymerases independently of the polymerases that started the upstream M gene transcription.

Amino Acid Sequence↗

PubMed1991

Sequence characterization of the matrix protein genes of parainfluenza virus types 4A and 4B.

The complete nucleotide sequences of the matrix protein (M) genes of parainfluenza virus types 4A and 4B (PIV-4A and -4B) were determined from cDNA of the mRNA, and found to be 1548 bases in length, exclusive of poly(A) sequences. The sequences contained a large open reading frame of 1146 nucleotides encoding 362 amino acids. A high degree of identity (96.1%) was observed between the amino acid sequences of PIV-4A and PIV-4B M. These M sequences were compared with those of 10 other paramyxoviruses and a phylogenetic tree was constructed.

Amino Acid Sequence↗

PubMed1991

Supersensitivity to tetrodotoxin and lignocaine of sea anemone toxin II-treated sodium channel in guinea-pig ventricular muscle.

1. Sea anemone toxin II (ATX II, 20-30 nM) doubled the action potential duration in guinea-pig papillary muscles without affecting the maximum rate of rise of the action potential (Vmax) and the resting potential. 2. Tetrodotoxin and lignocaine shortened the prolonged action potential in the ATX II-treated papillary muscles in concentrations (30 nM - 3 microM) at which these drugs did not suppress the Vmax. 3. Whole-cell voltage-clamp experiments with single ventricular cells showed that ATX II produced a slowly decaying inward sodium current following a transient sodium current upon depolarization. 4. The ATX II-induced slowly decaying current was reduced by tetrodotoxin or lignocaine in concentrations (300 nM-1 microM for tetrodotoxin, 3-10 microM for lignocaine) at which these drugs failed to affect the Vmax in cells not treated with ATX II. 5. These results suggest that sodium channel modification by ATX II not only changes its kinetics but also increases the susceptibility of the channel to block by tetrodotoxin and lignocaine.

Action Potentials↗

PubMed1991

[Effect of aging on in vivo binding of 11C-N-methylspiperone in living human frontal cortex].

Reduced in vivo binding of 11C-N-methylspiperone (NMSP) with age in the living human frontal cortex was demonstrated, with positron emission tomography (PET). Eleven normal male volunteers (22 to 72 years old) were assessed. The uptake of 11C-NMSP in the frontal cortex peaked 7-15 min after intravenous injection, and then gradually decreased until the end of this study. On the other hand in the cerebellum, the uptake of 11C-NMSP peaked 10 min and rapidly declined. We analyzed the data using a three compartment model and determined rate constants k3 and k4. And the binding potential of receptors was estimated as the ratio of k3 (association rate constant) to k4 (dissociation rate constant) value. The k3 and k4 values were calculated from nonlinear regression, given by the set of parameter values that minimized the deviation between the measured kinetics and model prediction. As an input function, we used the radioactivity in the cerebellum. A significant reduction in BP with age was observed. Though both k3 and k4 values were decreased with age, this decrease of BP was found to be mainly due to the reduced k3 values. These results indicated that numbers of binding sites (Bmax) of serotonin S2 receptors in frontal cortex might be decreased with age.

Adult↗

PubMed1991

Water loading tests both in supine and upright positions in three cases of idiopathic edema.

Three cases of idiopathic edema are reported with the results of water loading tests. Free water clearance and fractional sodium excretion revealed that three cases were different in water and sodium retention both in supine and upright positions. Aldosterone, plasma renin activity and antidiuretic hormone seemed to little to correspond to water and sodium retention; whereas atrial natriuretic peptide markedly increased in the upright position in all the cases. These data suggest that three cases cannot be explained by a single factor, but that enhanced reduction of venous return to the heart in the upright position may be a common feature in all three cases.

Adult↗

PubMed1991

[A case of primary intrapulmonary benign schwannoma].

A case of primary intrapulmonary schwannoma was described. A 72-year-old man was admitted to our hospital because of dry cough. A chest radiograph showed partial atelectasis of the middle lobe, but computed tomogram of the chest revealed no tumor shadow. Bronchoscopy disclosed a pale-yellow uneven endobronchial wall of the right middle lobe bronchus. Transbronchial biopsy revealed benign schwannoma. Primary intrapulmonary schwannoma has been rarely reported.

Aged↗

PubMed1990

Ethanol enhancement of GABA-activated chloride current in rat dorsal root ganglion neurons.

The acute effects of ethanol on the gamma-aminobutyric acid (GABA)-activated current were studied with the rat dorsal root ganglion neurons in primary culture using the whole-cell patch-clamp technique. GABA produced an inward chloride current, which was composed of an initial transient and a subsequent sustained phase. Ethanol at concentrations ranging from 30 to 300 mM enhanced the transient current in a concentration-dependent manner without affecting the sustained current.

Animals↗

PubMed1990

Sequencing analyses and comparison of parainfluenza virus type 4A and 4B NP protein genes.

The nucleotide sequences of the cDNA copies of the mRNA coding for the nucleocapsid proteins (NPs) of human parainfluenza viruses type 4A (PIV-4A) and type 4B (PIV-4B) were determined. The copy of PIV-4A NP mRNA contained 1885 nucleotides encoding a protein with a calculated molecular weight of 62,561. The same number of amino acids with a similar molecular weight (62,425) were predicted for the PIV-4B NP protein. Comparisons on the nucleotide sequence and the amino acid sequence of NP protein between these two subtypes revealed extensive homologies in the nucleotide sequence (87%) and in the amino acid sequence (93%). Furthermore, a conserved region with about 100 amino acids was observed between PIV-4s and other paramyxoviruses, Newcastle disease virus (NDV), Sendai virus, mumps virus (MuV), PIV-3, BPIV-3, measles virus (MV), and canine distemper virus (CDV), indicating a common ancestor for these nine viruses. Our data also indicated that the PIV-4 NP proteins were more closely related to MuV and NDV than to other parainfluenza viruses, PIV-3, BPIV-3, and Sendai virus. Interestingly, the NP protein homology between PIV-4s and the morbillivirus group, MV and CDV, was slightly higher than that between PIV-4s and the parainfluenza viruses, PIV-3, BPIV-3, and Sendai virus.

Amino Acid Sequence↗

PubMed1990

Sequence determination of the hemagglutinin-neuraminidase (HN) gene of human parainfluenza type 2 virus and the construction of a phylogenetic tree for HN proteins of all the paramyxoviruses that are infectious to humans.

The nucleotide sequence of the hemagglutinin-neuraminidase (HN) gene of human parainfluenza type 2 virus (PIV-2) was determined. The PIV-2 HN gene was 2112 nucleotides excluding poly(A) tail. There was a single large open reading frame in the mRNA which encoded a protein of 571 amino acids with a calculated molecular weight of 63,262. Analysis of the deduced amino acid sequence revealed that there were fourteen potential glycosylation sites and a major hydrophobic region near the N-terminus, which would anchor the protein in the viral membrane. Comparisons of the HN protein sequences of PIV-2 with those of Simian virus 5 (SV5), Sendai virus (SV, parainfluenza virus type 1), human parainfluenza virus type 3 (PIV-3), type 4 (PIV-4), bovine parainfluenza virus type 3 (BPIV-3), mumps virus (MuV), and Newcastle disease virus (NDV) showed definite amino acid sequence relatedness, indicating a common ancestor for these viruses. Furthermore, statistical analysis of the protein sequences suggested a possible evolutionary relatedness among the paramyxoviruses. This is the first time that a phylogenetic tree has been constructed for all the parainfluenza viruses and mumps virus which are infectious to humans. In addition, amino acid sequences involved in hemagglutinating and neuraminidase activities of paramyxovirus were discussed.

Amino Acid Sequence↗

PubMed1990

Antigenic and structural properties of a paramyxovirus simian virus 41 (SV41) reveal a close relationship with human parainfluenza type 2 virus.

Seven structural component proteins of a paramyxovirus simian virus 41 (SV41) were identified with the aid of monoclonal antibodies prepared against SV41 and human parainfluenza type 2 virus (PIV2). The nucleoprotein is antigenically very close to that of PIV2, while it is comparatively far from that of simian virus 5 (SV5). The hemagglutinin-neuraminidase (HN) protein showed no immunological relationship to either of the HN proteins of PIV2 or SV5. The amino acid sequence of the SV41 HN protein was deduced from the nucleotide sequence of its HN gene and revealed that the SV41 HN is unexpectedly close to the PIV2 HN (61.2% identity in amino acid sequence), while the SV5 HN showed only 48.3% identity with the PIV2 HN. The SV41 HN is also related to the SV5 HN (51.3% identity); thus, the SV41 HN is phylogenetically situated between the PIV2 and SV5 HNs. These results indicate that SV41 is the virus closest to PIV2 at present.

Amino Acid Sequence↗

PubMed1990

Sequence analyses of the 3' genome end and NP gene of human parainfluenza type 2 virus: sequence variation of the gene-starting signal and the conserved 3' end.

We cloned and determined the nucleotide sequences of cDNAs against nucleocapsid protein (NP) mRNA and the genomic RNA of human parainfluenza type 2 virus (PIV-2). The 3' terminal region of genomic RNA was compared among PIV-2, mumps virus (MuV), Newcastle disease virus (NDV), measles virus (MV), PIV-3, bovine parainfluenza type 3 virus (BPIV-3), Sendai virus (SV), and vesicular stomatitis virus (VSV), and an extensive sequence homology was observed between PIV-2 and MuV. Although no significant sequence relatedness was observed between PIV-2 and other viruses, the terminal four nucleotides were identical in the viruses compared, implying a specific role of these nucleotides on the replication of paramyxoviruses. A primer extension analysis elucidated the major NP mRNA initiation site with the sequence UCUAAGCC, which showed a moderate homology with the gene-starting consensus sequences of other paramyxoviruses. On the other hand, the NP mRNA was terminated at the nucleotide stretch AAAUUCUUUUU, and this sequence was conserved in all the PIV-2 genes, indicating that the oligonucleotides will form a part of the gene attenuation signal of PIV-2. Comparisons of NP protein sequence indicated a possible subgrouping of the paramyxoviruses into two groups, one of which is a group including PIV-2, PIV-4, MuV, and NDV, and another is a group including PIV-3, BPIV-3, and SV. This result supports an idea from our previous studies using polyclonal and monoclonal antibodies. Furthermore, our data indicated that the PIV-2 NP protein sequence was more closely related to MV and CDV than to other parainfluenza viruses, PIV-3 and SV.

Amino Acid Sequence↗

PubMed1990

Complete nucleotide sequence of the matrix gene of human parainfluenza type 2 virus and expression of the M protein in bacteria.

The sequence of the M gene of human parainfluenza virus type 2 (PIV-2) has been determined. The sequence contained a large open reading frame with 1131 nucleotides encoding a protein with a calculated molecular weight of 42,312. Comparison of M protein sequence indicated that PIV-2 was more closely related to mumps virus and Newcastle disease virus than to other parainfluenza viruses, Sendai virus (SV), and parainfluenza virus type 3 (PIV-3), indicating a possible subdividing of the Paramyxovirus into two groups. This grouping is consistent with that obtained from analysis of the HN gene. Measles virus and canine distemper virus definitely belong to the subgroup composed of SV and PIV-3. No homology region was found in all the paramyxoviruses compared. However, a tertiary structure may be conserved in each subgroup of paramyxovirus. The M protein of PIV-2 was expressed in bacteria, and the product was recognized by a monoclonal antibody specific for the PIV-2 M protein. The bacterial-expressed protein, however, was heterogeneous and smaller in size.

Amino Acid Sequence↗

PubMed1990

Molecular cloning and sequence analysis of human parainfluenza type 4A virus HN gene: its irregularities on structure and activities.

We cloned the cDNA of human parainfluenza type 4A virus (PIV-4A) HN gene by reverse-transcription of virus-specific mRNAs and genomic RNA, and determined the complete nucleotide sequence of the HN gene. The predicted HN protein sequence of PIV-4A showed significant relatedness with those of other paramyxoviruses, SV5, NDV, MuV, PIV-3, BPIV-3, indicating a common ancestor. The homologies between the viruses suggested that PIV-4A is more closely related to NDV, SV5, and MuV than to the parainfluenza viruses, PIV-3, bovine parainfluenza type 3 virus (BPIV-3), and Sendai virus (SV). Sixty amino acids were commonly conserved among the viruses, other than PIV-4A. Two of these amino acids were substituted in PIV-4A HN and are predicted to be located near the active site of the neuraminidase. The analysis of neuraminidase of PIV-4 revealed that the activity is hardly detectable, suggesting the significant effect of the substituted amino acid sites on neuraminidase activity.

Amino Acid Sequence↗

PubMed1990

Sequence of the fusion protein gene of human parainfluenza type 2 virus and its 3' intergenic region: lack of small hydrophobic (SH) gene.

cDNA clones representing the fusion (F) gene of human parainfluenza virus type 2 (PIV-2) were isolated from cDNA libraries constructed from virus-specific mRNA and genomic RNA, and the complete nucleotide sequence of the F gene was determined. The F gene is 1854 nucleotides long and encodes one long open reading frame of 551 amino acids. The cleavage site for activation of the precursor Fo protein is Thr-Arg-Gln-Lys-Arg. The F gene of PIV-2 is most closely related to those of simian virus 5 (SV5) and mumps virus (MuV). Interestingly, although the HN glycoprotein of PIV-2 shows no relatedness to the HA glycoprotein of measles virus (MV), a distinct homology is found in the F proteins of PIV-2 and MV. As concerns F proteins, paramyxoviruses can be divided into two subgroups; that is, PIV-2, SV5, and MuV belong to one group, and HPIV-1, SV, and PIV-3 belong to the other group. Newcastle disease virus (NDV) and MV are intermediate. Coding regions for small hydrophobic (SH) proteins have been found between the HN and F genes of SV5 and MuV, which are the viruses most closely related to PIV-2. However, such a gene could not be detected in two different strains of PIV-2.

Amino Acid Sequence↗

PubMed1990

Sequence analysis of the phosphoprotein (P) genes of human parainfluenza type 4A and 4B viruses and RNA editing at transcript of the P genes: the number of G residues added is imprecise.

We cloned and sequenced the cDNAs against genomic RNAs and mRNAs for phosphoproteins (Ps) of human parainfluenza virus types 4A (PIV-4A) and 4B (PIV-4B). The PIV-4A and -4B P genes were 1535 nucleotides including poly(A) tract and were found to have two small open reading frames, neither of which was apparently large enough to encode the P protein. A cluster of G residues was found in genomic RNA and the number of G residues was 6 in both PIV-4A and -4B. However, the number of G residues at the corresponding site in the mRNAs to the genomic RNA was not constant. Three different mRNA cDNA clones were obtained; the first type of mRNA encodes a larger (P) protein of 399 amino acids, the second type encodes V protein of 229 or 230 amino acids, and the third type encodes the smallest protein (156 amino acids). Comparisons on the nucleotide and the amino acid sequences P and V proteins between these two subtypes revealed extensive homologies. However, these homology degrees are lower than that of NP protein. The C-terminal regions of the P and V proteins of PIV-4s could be aligned with all other Paramyxoviruses, PIV-2, mumps virus (MuV), simian virus 5 (SV 5), Newcastle disease virus (NDV), measles virus (MV), canine distemper virus (CDV), Sendai virus (SV), and PIV-3. On the other hand, the P-V common (N-terminal) regions showed no homology with MV, CDV, SV, and PIV-3. Seven phylogenetic trees of Paramyxoviruses were constructed from the entire and partial regions of P and V proteins.

Amino Acid Sequence↗

PubMed1990

Sequence analysis of P gene of human parainfluenza type 2 virus: P and cysteine-rich proteins are translated by two mRNAs that differ by two nontemplated G residues.

We cloned and sequenced the cDNAs against genomic RNA and mRNA for phosphoprotein (P) of human parainfluenza type 2 virus (PIV-2). cDNA clone from genomic RNA was 1439 nucleotides in length excluding poly(A) and was found to have two small open reading frames encoding proteins of 233 and 249 amino acids. Two different mRNA cDNA clones were obtained; that is, one mRNA contained a smaller reading frame coding 225 amino acids, V protein, and the other mRNA contained a larger reading frame coding 395 amino acids, P protein. Both mRNAs had G cluster in coding frame. The former mRNA contained seven G residues, and two extra G residues were inserted in the latter mRNA. Ten cDNA clones from the genomic RNA were identical and were composed of seven G residues, indicating that genomes analyzed here were a homogeneous population. Therefore, V protein is encoded by faithfully copied mRNA and P protein is translated from mRNA in which two additional G residues are nontemplately inserted immediately after seven genomically encoded G residues. The V and P proteins are amino coterminal proteins and have different C termini. The C terminus of V protein is cysteine-rich and bears some resemblance to metal-binding protein of the zinc finger-type motif. P protein sequence of PIV-2 showed high homologies with SV 5 (40.4%) and mumps virus (35.5%), and a moderate homology with Newcastle disease virus (20.6%). On the other hand, very little homology was found between PIV-2 and other paramyxoviruses including Sendai virus, PIV-3, and measles virus. The cysteine-rich region in V protein was found to be highly conserved in PIV-2, SV 5, and measles virus, suggesting that V protein of paramyxoviruses plays important roles in transcription and/or replication. The predicted cysteine-rich V protein was detected in virus-infected cells using antiserum directed against an oligopeptide specific for the predicted V polypeptide.

Amino Acid Sequence↗

PubMed1990

Effects of TYB-3823, a new antiarrhythmic drug, on the electrophysiological properties of guinea-pig ventricular muscles.

1. The effects of TYB-3823 (B-GYKI 38233), a new antiarrhythmic drug, were electrophysiologically examined in the guinea-pig ventricular muscles. 2. TYB-3823 at concentrations of 1-3 x 10(-7) M significantly prolonged the action potential duration (APD) of the papillary muscle. However, the resting potential, action potential amplitude and maximum rate of depolarization (Vmax) were unaffected by the drug at such concentrations. At a higher concentration (1 x 10(-4) M) TYB-3823 reduced Vmax. 3. Voltage clamp experiments with single ventricular cells revealed that TYB-3823 at concentrations higher than 1 x 10(-7) M reduced the outward potassium currents, especially the time-dependent outward current, but that TYB-3823 failed to affect the calcium current. 4. These results suggested that TYB-3823 at low concentrations reduces the outward potassium current to give rise to a prolongation of APD and that at higher concentrations it additionally inhibits the sodium channels; both the effects may be related to the antiarrhythmic action of this drug.

Action Potentials↗

PubMed1990

Antiviral effect of 6-diazo-5-oxo-L-norleucine, antagonist of gamma-glutamyl transpeptidase, on replication of human parainfluenza virus type 2.

The antiviral effects of 6-diazo-5-oxo-L-norleucine (L-DON) on the replication of human parainfluenza virus type 2 (HPIV-2), mumps and vesicular stomatitis viruses were studied. L-DON suppressed growth of these viruses and, in particular, HPIV-2 in four cell types. L-DON was not toxic to the cells at the active dose and did not significantly inhibit cellular macromolecular synthesis. The L-DON-sensitive step of HPIV-2 replication was considered to be relatively early. The NP, P and M proteins were, although at a low level, clearly detectable in HPIV-2-infected Vero cells treated with L-DON, whereas the HN and F proteins were scarcely detected by either immunostaining or immunoprecipitation, indicating that L-DON mainly decreased the amounts of viral glycoproteins. Furthermore, Northern blot hybridization showed that secondary transcription of virus RNA was also inhibited.

Animals↗