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Biomedical subjects

Y Ohtsu

Publications and source records attributed to Y Ohtsu.

At least 19 recordsLinked to original sources
PubMed2006

Current-free double-layer formation in inductively coupled plasma in a uniform magnetic field.

The axial profiles of plasma parameters for low and moderate pressures, such as the plasma potential, electron temperature, and number density, have been evaluated in magnetized inductively coupled plasma. The experimental results revealed in both cases the existence of a genuine current-free double-layer structure, separating two plasma regions with different properties. Based on the experimental results, a physical scenario for the self-assembling of the double layer is proposed. Also, the axial profile of the electron number density downstream is analyzed, emphasizing the role of neutral metastable ionization, and a simple analytical model is developed to fit the experimental data. The model allows the estimation of neutral metastable number density downstream and the recombination rate coefficient.

Journal Article↗
PubMed2003

Complete nucleotide sequences of genome segments 1 and 3 of Rosellinia anti-rot virus in the family Reoviridae.

The nucleotide sequences of genome segments 1 and 3 of Rosellinia anti-rot virus (RArV) from a hypovirulent isolate, W370, of the plant pathogen Rosellinia necatrix were determined. The complete nucleotide sequence of the genome segment 1 encoded a putative RNA-dependent RNA polymerase (RDRP). The deduced amino acid sequence of RDRP of RArV showed 29% identity with RDRPs of Colorado tick fever virus (CTFV) and European Eyach virus (EYAV) in the genus Coltivirus, and identities of 23-21% with members of the genera Fijivirus and Cypovirus. Both RArV and the Coltivirus member might have originated from a common virus ancestor.

Ascomycota↗
PubMed2002

Interrupted aortic arch with ventricular septal defect: an unsuspected fatal congenital anomaly in forensic pathology.

Interrupted aortic arch (IAA) is a relatively rare cardiovascular anomaly worldwide and is very rarely encountered in forensic pathology. A case of clinically unsuspected fatal IAA in a 5-day old neonate is described. A full term female baby was declared dead on arrival at an emergency hospital few hours after having been discharged from a maternity hospital following delivery. There were no noticeable signs and symptoms reported during the short postnatal period. Antenatal medical history was unremarkable and there were no abnormalities noticed at birth. Autopsy revealed an unsuspected IAA arch with ventricular septal defect (VSD) as cause of sudden unexpected death. Although amenable to surgical intervention, IAA may not produce obvious clinical symptoms as was the case for this baby. Such sudden unexpected deaths raise medico-legal questions as to the manner and the precise cause of death. The importance of a full forensic autopsy to clarify such a sudden death was re-emphasized.

Journal Article↗
PubMed2001

Unusual homicide by air gun with pellet embolisation.

A homicidal case by an air gun involving a 73-year-old woman who was found dead in her home is described. At autopsy, two gunshot wounds were observed on the left anterior chest and the right back. There was neither exit wound nor powder burns. The fatal pellet, 0.9 g and 5.5mm diameter, penetrated the left anterior chest and the heart to cause cardiac tamponade (200 ml) before lodging in the left subclavian artery. Death was due to cardiac tamponade. This case has exhibited two rare phenomena: homicide by an air gun and pellet embolisation. This is the first homicide case by use of air gun in Japan and demonstrates that although it may be rare, air guns can be used as potential homicidal weapons. This experience will alert our society and others on the potential hazards of air guns we have tended to regard as toys.

Aged↗
PubMed2001

Preparation strategy for uniformly sized, polymer-based HPLC packing materials having practically acceptable column efficiency. 1. Copolymerization technique.

Uniformly sized, polymer-based packing materials affording excellent chromatographic performance in semimicro HPLC were prepared from mixtures of alkyl methacrylate and glycerol dimethacrylate by a copolymerization technique using a multistep swelling and polymerization method. A column efficiency of up to 13000 plates was obtained for a 2-mm-i.d. x 150-mm column with beads prepared from a 1:1 (v:v) mixture of an alkyl methacrylate and glycerol dimethacrylate. The packing materials exhibit a considerable improvement in column efficiency, as demonstrated on the separation of polyaromatic hydrocarbons (PAHs) having a relatively long retention time, which thus far has been a serious problem of polymer-based packing materials. Detailed studies suggested a rather limited optimum pore size, and its distribution was depicted to get the excellent column efficiency on polymer-based packing materials.

Journal Article↗
PubMed2001

Influenza virus RNA polymerase PA subunit is a novel serine protease with Ser624 at the active site.

BACKGROUND: Influenza virus RNA polymerase is a multifunctional enzyme that catalyses both transcription and replication of the RNA genome. The function of the influenza virus RNA polymerase PA subunit in viral replication is poorly understood, although the enzyme is known to be required for cRNA --> vRNA synthesis. The protease related activity of PA has been discussed ever since protease-inducing activity was demonstrated in transfection experiments. RESULTS: PA protein was highly purified from insect cells infected with the recombinant baculovirus carrying PA cDNA, and a novel chymotrypsin-type serine protease activity was identified with the synthetic peptide, Suc-LLVY-MCA, in the PA protein. [3H]DFP was crosslinked with PA and a mutational analysis revealed that serine624 was as an active site for the protease activity. CONCLUSIONS: These results constitute the demonstration of protease activity in PA subunit of the influenza virus RNA polymerase complexes.

Amino Acid Sequence↗
PubMed2001

Molecular evolution of human echovirus 9 isolated from patients with aseptic meningitis in northern Kyushu during the summer of 1997.

An epidemic of aseptic meningitis caused by human echovirus 9 (E-9) occurred in the summer of 1997 in northern Kyushu, Japan. Sequences of genome position 2504-3358, which encoded a part of VP1, of the nine isolated viruses were determined. An RGD motif and B-C loop were found in all. They were almost identical and closely related to the virulent strain Barty.

Amino Acid Sequence↗
PubMed2000

Inhibition of influenza virus replication in cultured cells by RNA-cleaving DNA enzyme.

Influenza virus replication has been effectively inhibited by antisense phosphothioate oligonucleotides targeting the AUG initiation codon of PB2 mRNA. We designed RNA-cleaving DNA enzymes from 10-23 catalytic motif to target PB2-AUG initiation codon and measured their RNA-cleaving activity in vitro. Although the RNA-cleaving activity was not optimal under physiological conditions, DNA enzymes inhibited viral replication in cultured cells more effectively than antisense phosphothioate oligonucleotides. Our data indicated that DNA enzymes could be useful for the control of viral infection.

Animals↗
PubMed2000

Antibody-scanning and epitope-tagging methods; molecular mapping of proteins using antibodies.

Because synthetic short peptides bearing critical binding residues, can chemically mimic the folded antigenic determinants on proteins, short synthetic peptides can generate antibodies that react with cognate sequences in intact folded proteins. According to this mimotope theory, we produced site-specific antibodies by immunization with short peptides which overlapped each other and covered the entire protein, and used them for domain mapping of influenza virus RNA polymerase (antibody-scanning method). We also used a tagged-epitope and its monoclonal antibodies for topology mapping of clathrin light chains in clathrin triskelions by electron microscopy. Both methods using specific epitopes in combination with their antibodies enable us to determine the domains of interesting proteins systematically without the need to generate monoclonal antibodies or mutant proteins.

Amino Acid Sequence↗
PubMed2000

Japanese monozygotic twins with familial amyloidotic polyneuropathy (FAP) (ATTR Val30Met).

Twenty-nine-year-old twin brothers having the amyloidogenic transthyretin (ATTR) Val30Met gene developed the clinical symptoms of familial amyloidotic polyneuropathy (FAP) in 1995. The twins had the same educational background and lived in the same district. FAP manifestations were similar in both cases, although electromyographic examinations revealed sensorimotor polyneuropathy in No. 1 and sensory polyneuropathy in No. 2. DNA analysis revealed that they were monozygotic twins. In addition to environmental factors, genetic factors may play an important role in determining the onset of FAP.

Adult↗
PubMed1999

Perinatal outcome and management of single fetal death in twin pregnancy: a case series and review.

OBJECTIVE: To determine neonatal outcome of single fetal death in twin pregnancy. METHODS: Retrospective study was performed on 30 cases of single fetal death in twin pregnancy during the period from August 1971 to December 1997 at Kitasato university hospital. RESULTS: The incidence of single fetal death in twin pregnancy was 6.2% among total number of 481 twins. Prognosis of surviving infants was satisfactory except in one case, with malformation in 10 cases of dichorionic twins (total 242 sets). In contrast, neonatal death occurred in 6 cases of 20 monochorionic twins (total 239 sets), 4 of which were among 7 cases of twin-to-twin transfusion syndrome (TTTS). Cerebral palsy occurred in 2 infants of monochorionic twins. One case was diagnosed as periventricular leukomalacia (PVL) within one week after birth, and this was the case of delivery 1 day after one twin fetal death. CONCLUSION: Single fetal death itself occurs more often in monochorionic twins. There seems to be a benign outcome for the surviving dichorionic twins. On the other hand, there may be a grave outcome, though infrequent, for monochorionic twins when concomitant TTTS has existed. It is very important to identify the chorionicity by ultrasound examination in early pregnancy.

Diseases in Twins↗
PubMed1998

Nucleotide sequence of the gene encoding the RNA polymerase and the 3' non-coding region of a bovine enterovirus Japanese isolate: rapid synonymous substitutions between European and Japanese strains.

The nucleotide sequences of the genome RNA encoding the RNA polymerase and the 3' non-coding region (NCR) of bovine enterovirus (BEV) serotype I Japanese isolate, MZ468, were determined. The genetic distance between the two BEV serotype I strains, MZ468 and VG-5-27, was calculated by pairwise comparison of nucleotide sequences. The synonymous substitution rate was high (1.40 x 10(-2)/site/year), and of the same order as those of influenza virus HA, HIV-1 gag and env, and enterovirus 70 VP1 genes.

Amino Acid Sequence↗
PubMed1998

Death as a result of heat stroke in a vehicle: an adult case in winter confirmed with reconstruction and animal experiments.

A 54-year-old man was found dead in the driver's seat of his vehicle on a winter's day. Investigations of the vehicle revealed that the engine was running, and the car heater was left on with the maximum temperature and velocity. The body was found excessively sweating. Rectal temperature of the body was 43 degrees C at 10 h post mortem. In autopsy, several superficial skin burns were observed on the face, the shoulders and the legs. The lungs were heavily congested and hemorrhagic. The liver showed typical alcohol-induced micronodular cirrhosis. The alcohol concentrations were 0.17% in the blood of both the left and the right heart, 0.17% in the femoral-vein blood, 0.21% in the bladder urine and 0.34% in the gastric contents. A reconstruction experiment demonstrated that the temperature inside the vehicle rose rapidly and reached 50-58 degrees C in 3 h. Animal experiments showed that the temperature threshold for rats to succumb to heat was between 40 and 45 degrees C. This case shows that heat stroke in a vehicle can occur in adults with chronic diseases or alcoholism, such as in this particular case, even in the winter.

Journal Article↗
PubMed1998

Nucleotide sequence of seed- and pollen-transmitted double-stranded RNA, which encodes a putative RNA-dependent RNA polymerase, detected from Japanese pear.

The nucleotide sequence of the largest double-stranded (ds) RNA (named dsRNA1) of three species of seed- and pollen-transmitted dsRNA species detected from Japanese pear was analyzed, and one strand was found to contain a single long open reading frame (ORF) of 1434 nucleotides that encoded a putative polypeptide containing 477 amino acid residues with a molecular mass of 54.9 kDa. This polypeptide contained amino acid sequence motifs conserved in putative RNA-dependent RNA polymerases of RNA viruses. Attempts to visually identify or purify virus-like particles associated with the dsRNAs were unsuccessful. Slow sedimentation of the dsRNA fraction suggests that the dsRNAs may be unencapsidated. The concentration of dsRNAs in the host, Japanese pear, was about 16 times higher than that from a cryptic virus, radish yellow edge virus (RYEV). These results suggest that the dsRNAs were not from cryptic viruses. Partial nucleotide sequences of the two smaller dsRNAs (named dsRNAs 2 and 3) and two other dsRNAs (named dsRNAs 4 and 5) detected from only the Japanese pear cultivar (cv.) Akita Tazawa 3 Gou were analyzed, and encoded nearly the same amino acid sequence encoded by dsRNA1.

Amino Acid Sequence↗
PubMed1997

Analysis of ibuprofen metabolites by semi-microcolumn liquid chromatography with ultraviolet absorption and pulsed amperometric detectors.

Semi-microcolumn (1.5 mm i.d.) liquid chromatography (LC) system with ultraviolet (UV) and pulsed amperometric detector (PAD) was constructed for analysis of ibuprofen metabolites in human urine. PAD was connected in series with the UV detector, and an alkaline solution was post-column added to a mobile phase after the UV detector. By a gradient elution, five ibuprofen metabolites were detected with UV detection from 1 microliter of human urine at 3.5 h after the administration, and information concerning their glucuronation was simultaneously obtained by PAD response.

Adult↗
PubMed1996

Synthesis and characterization of polymer-coated mixed-functional stationary phases with several different hydrophobic groups for direct analysis of biological samples by liquid chromatography.

Three types of polymer-coated mixed-functional (PCMF) silica column-packing materials for the direct analysis of biological liquids have been synthesized. These packing materials all have polyoxyethylene groups as their hydrophilic part but differ in their hydrophobic part (methyl groups for Me-POE, phenyl groups for Ph-POE, and octyl groups for Oc-POE). Retention characteristics with respect to several drug molecules, and protein recovery, were studied for each of the three types with different amounts of hydrophobic groups attached. Of the PCMFs prepared, Oc-POE showed the greatest overall retention, and Me-POE displayed the greatest protein recovery.

Anti-Bacterial Agents↗
PubMed1994

Synthesis of polymer-coated mixed-functional packing materials for direct analysis of drug-containing serum and plasma by high-performance liquid chromatography.

Silicone polymer-coated mixed-functional (PCMF) silica packing materials were developed for the direct determination of drugs contained in serum or plasma. The new stationary phases were prepared by the following three-step procedure: (1) coating porous silica with a silicone polymer; (2) partial introduction of hydrophobic groups; and (3) introduction of hydrophilic groups. Two PCMFs were synthesized, one having polyoxyethylene groups as hydrophilic groups (PCMF-POE) and the other having oligoglyceryl groups (PCMF-OG). PCMF-POE showed higher recoveries for injected proteins and a greater overall retention for drug molecules than PCMF-OG. PCMF-POE did not show any column deterioration in 500 serum sample injections (10 ml in total).

Carbamazepine↗