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Biomedical subjects

G Sato

Publications and source records attributed to G Sato.

At least 55 records · Page 3Linked to original sources
PubMed1988

Nucleotide sequence of insertion sequence IS3411, which flanks the citrate utilization determinant of transposon Tn3411.

The nucleotide sequences of insertion sequences IS3411L (left) and IS3411R (right), present as direct terminal repeats in the citrate utilization of citrate utilization transposon Tn3411, and of IS3411 (generated by intramolecular recombination between IS3411L and IS3411R) were determined. The three IS3411 elements (IS3411R, IS3411L, and IS3411) were 1,309 base pairs long and identical in DNA sequence. IS3411 had 27-base-pair terminal inverted repeats with three bases mismatched and one long open reading frame (240 amino acids) that was proposed to be a transposase. Three polypeptides of 29,000, 27,000, and about 10,000 molecular weight, determined by IS3411, were identified in minicells. Since Tn3411 generates a 3-base-pair repeat upon integration, the nucleotide sequences of IS3411 were compared with those of IS3.

Amino Acid Sequence↗
PubMed1987

Quantitative autoradiographic analysis of muscarinic cholinergic and adenosine A1 binding sites after transient forebrain ischemia in the gerbil.

The influence of transient forebrain ischemia on adenosine A1 and muscarinic cholinergic receptors in the gerbil brain 1-27 days after recirculation was studied. The topographical distribution and the alteration in the adenosine A1 and muscarinic receptor sites were analyzed by means of quantitative receptor autoradiography using [3H]cyclohexyladenosine ([3H]CHA) and [3H]quinuclidinyl benzilate ([3H]QNB), respectively. In most regions examined, the temporal profiles of the alteration of the receptor density were in accordance with the histopathological findings. [3H]CHA binding activity decreased suddenly after neuronal damage, while [3H]QNB grain density showed a gradual decrease in the dorsolateral caudate-putamen and in the CA1 subfield of the hippocampus. In the caudate-putamen, [3H]CHA and [3H]QNB binding activity in the dorsal aspect was markedly reduced 1-27 days after ischemia. [3H]CHA binding activity in the ventromedial region of the caudate-putamen also decreased 1-3 days after ischemia, though neuronal damage was restricted to the dorsolateral aspect. Neuronal death in CA1 was preceded by the decrease in [3H]QNB binding activity in the stratum radiatum 1 and 2 days after ischemia. Marked decrease in [3H]QNB and [3H]CHA binding activity was noted in the CA1 subfield 3-27 days after recirculation. Three to 27 days after ischemia, the A1 binding activities in the CA3 subfield of the hippocampus and in the dentate gyrus were reduced despite the normal appearance of these areas throughout the reperfusion period. Muscarinic binding sites in the CA3 subfield were also reduced 27 days after ischemia. Despite minimal neuronal damage in the lateral septal nucleus and in the substantia nigra, the A1 binding activity in these regions was reduced by 70% and 50%, respectively. These results provide further evidence that the muscarinic receptors in the dorsolateral region of the caudate-putamen are localized postsynaptically on small and medium-sized neurons and that those in the CA1 subfield of the hippocampus are localized on the CA1 pyramidal cells.

Adenosine↗
PubMed1987

Phylogenetic relationships between adenoviruses as inferred from nucleotide sequences of inverted terminal repeats.

The nucleotide (nt) sequences of inverted terminal repeats (ITR) from human adenovirus (Ad) 19, bovine Ad1 (BAd1), bovine Ad3 (BAd3), canine Ad2 (CAd2) and an avian Ad, EDS-76, were determined. The length of the ITR sequence was 160 bp in Ad19, 159 bp in BAd1, 195 bp in BAd3, 196 bp in CAd2 and 52 bp in EDS-76. CAd2 had the longest ITR among the examined Ads, BAd3 the second longest, and EDS-76 had the shortest ITR. A TAAT sequence located between the 10th and 13th nt counted from the ends was conserved in all Ads examined so far. To determine phylogenetic relationships among human and animal Ads, sequences of their ITRs were compared, and a phylogenetic tree was constructed by using the maximum-likelihood method. It is the method involving statistical analysis of computing the probability of a particular set of sequences on a given tree and maximizing this probability over all evolutionary trees [Felsenstein, J. Mol. Evol. 17 (1981) 368-376]. From these analyses, it was found that members belonging to the same human Ad subgenus are related closely to each other, whereas representatives of different human subgenera are distributed rather divergently among animal Ads.

Adenoviridae↗
PubMed1987

GABA and benzodiazepine receptors in the gerbil brain after transient ischemia: demonstration by quantitative receptor autoradiography.

Quantitative receptor autoradiography was used to measure the binding of gamma-aminobutyric acid (GABA) and benzodiazepine receptors after ischemia by means of transient occlusion of bilateral common carotid arteries in the gerbil. [3H]Muscimol was used to label the GABAA receptors and [3H]flunitrazepam to label central type benzodiazepine receptors. In the superolateral convexities of the frontal cortices, [3H]muscimol binding was increased in 60% of the animals killed 3 days after ischemia, and decreased in 67% of the animals killed 27 days after ischemia. Twenty-seven days after ischemia, [3H]flunitrazepam binding in the substantia nigra pars reticulata increased to 252% of the control, though the increase in [3H]muscimol binding was not significant. In the dorsolateral region of the caudate putamen, marked neuronal necrosis and depletion of both [3H]muscimol and [3H]flunitrazepam binding sites were observed 27 days after ischemia, the ventromedial region being left intact. In spite of the depletion of pyramidal cells in the CA1 region of the hippocampus, both [3H]muscimol and [3H]flunitrazepam binding sites were preserved 27 days after ischemia. Since our previous study revealed that adenosine A1 binding sites were depleted in the CA1 subfield of the hippocampus after ischemia correlating with neuronal damage, GABAA and benzodiazepine receptors may not be distributed predominantly on the pyramidal cells in the CA1 region.

Animals↗
PubMed1986

Lesions to Schaffer collaterals prevent ischemic death of CA1 pyramidal cells.

The contribution of excitatory inputs to CA1 pyramidal cell death after ischemia was examined using rats with unilateral destruction of CA3 pyramidal cells. Intracerebroventricular injection of L-alpha-kainic acid (KA) was performed before the induction of transient forebrain ischemia. Five days after ischemic insult, pyramidal cells and L-glutamate binding sites in the CA1 region ipsilateral to the KA injection were preserved in spite of neuronal necrosis and a significant decrease in L-glutamate receptor density in the contralateral CA1 region, indicating the critical role of Schaffer collaterals in delayed neuronal death.

Animals↗
PubMed1986

Generation of packaging-defective DNA molecules of equine adenovirus.

Equine adenovirus (EAd) DNA prepared from infected bovine kidney (MDBK) cells contained additional sequences of about 100 to 700 bp at the left-hand end of the genome. These aberrant viral genomes were produced even after the first passage of the wild type EAd in MDBK cells and their relative amounts did not change significantly during serial passage. The left terminal fragments of two defective viral DNAs were cloned into the plasmid vector pBR322 and the nucleotide sequences of their terminal regions were analyzed. The data indicate that one viral DNA contained a duplication of the inverted terminal repetition (ITR) and the other contained 270 bp of additional sequences derived from the right-terminal region of EAd genome added to the left-terminal, ITR. While the former DNA was packaged into virions, the latter was not, presumable due to the alteration of the distance from the left terminus to the putative DNA packaging signal, reported to be located between 290 and 390 bp (Hammarskjold and Winberg, 1980). The possible mechanism for the generation of these defective DNAs is discussed.

Adenoviridae↗
PubMed1986

Immunoreactivity of a synthetic pentadecapeptide corresponding to the N-terminal region of the scrapie prion protein.

A pentadecapeptide with an amino acid sequence corresponding to the amino-terminal region of the scrapie prion protein was synthesized. Immunization of a rabbit with the peptide conjugated with ovalbumin induced specific antibodies. The antibodies reacted with all three of the major polypeptides in a proteinase K-treated fraction obtained from brains of mice infected with the Obihiro strain of scrapie agent. Some peptides in the proteinase-untreated fraction also shared antigenicity with the three major polypeptides. Specific polypeptides were also detected by the antiserum in a fraction prepared from spleens, but only two of the three major polypeptides were found and the amounts of the polypeptides were less than in brain.

Animals↗
PubMed1986

Purification of scrapie agent from infected animal brains and raising of antibodies to the purified fraction.

The fraction (P4) containing scrapie infectivity was obtained by treatment of scrapie-infected mouse brains with the detergent sarcosyl, differential centrifugation, and proteolytic enzyme digestion. Scrapie infectivity in the P4 fraction was purified 239-2,390 times with respect to protein. Similar fractions were also prepared from the brain of a sheep naturally infected with scrapie. Morphological observation of the P4 fractions revealed that the main components were unique rods of 3-5 X 60-200 nm, which resembled scrapie-associated fibrils (SAF) or prion rods. The P4 fractions formed three major broad bands of polypeptides with molecular weights (MWs) of about 24.5K, 21K, and 17K dalton (Kd) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and some low MW polypeptides were also present in the fraction. Rabbits immunized with this fraction prepared from mouse brains raised antibodies against the three major polypeptides.

Animals↗
PubMed1986

MDBK nuclear factor-binding site of various serotypes of adenovirus DNA.

A fraction with the ability to bind the terminal fragment of equine adenovirus (EAd) DNA was prepared from MDBK cell nuclei. The fraction (MDBK nuclear factor) bound to the terminal fragment of all human and animal adenovirus DNAs examined except avian adenovirus EDS-76. However, the terminal fragments of two animal adenoviruses, EAd and bovine adenovirus type 3 (BAd3), showed higher affinity for the nuclear factor than the others. The MDBK nuclear factor-binding site determined by footprinting analysis was the sequence located between nucleotides 22 and 46 in EAd, between 36 and 53 in canine adenovirus type 2, and between 20 and 46 in BAd3, counting from the terminus. The respective binding site contained a sequence resembling the consensus sequence. The binding site of Ad4 DNA was not within the inverted terminal repetition, but was located at least 550 base pairs apart from the terminus.

Adenoviridae↗
PubMed1986

Conservation of DNA sequences for plasmid-mediated citrate utilization within the enterobacteria.

Southern blot DNA-DNA hybridization experiments with a cloned Cit+ DNA fragment as a probe showed that the plasmid-mediated Cit+ determinants from four Cit plasmids (R726, pOH3001, pOH3035, and pOH30221) were all homologous. Sequences homologous to the plasmid-borne Cit+ gene were also found in total bacterial DNA isolated from Salmonella paratyphi B, Salmonella enteritidis, Salmonella typhimurium LT-2, Citrobacter freundii, ATCC 8090, Citrobacter amalonaticus ATCC 25405, Klebsiella pneumoniae I and IID 977, and Enterobacter aerogenes ATCC 13048. The DNA digest from C. amalonaticus ATCC 25405 contained a 1.4-kilobase BamHI-HincII DNA fragment that was strongly homologous with and identical in size to the plasmid Cit+ probe.

Base Sequence↗
PubMed1986

Difference in prognosis between T- and B-cell lymphomas: clinical study at Shikoku Cancer Center Hospital.

In order to determine whether the surface marker phenotypes of non-Hodgkin's lymphomas affect the prognosis, we have studied the differences in response rate and duration of survival between T- and B-cell lymphomas. Sixty-four patients who underwent first-line therapy, including combination chemotherapy and/or radiotherapy, from February 1979 to August 1985 were evaluated. With the aid of standard immunological methods and monoclonal antibodies related to T-cells and B-cells, 21 T-cell lymphomas and 21 B-cell lymphomas were identified. In the other 22 cases phenotypes were not determined mainly because of the inability to obtain fresh samples. The complete remission rate was 100% for B-cell lymphomas and 52.3% for T-cell lymphomas. The median survival time for patients with lymphomas of Stage III and IV, excluding those with low-grade histology, was nine months for T-cell lymphomas and 17 months for B-cell lymphomas. T-cell lymphomas were found to have significantly poorer prognosis than B-cell lymphomas. One patient with B-cell lymphoma and six patients in an undetermined phenotype group, who were treated with combination chemotherapy, have been alive more than three years without relapse and these patients are considered potentially cured. Our results suggest that the surface marker phenotype study of lymphoma cells as well as histological subtyping is important in prognosis and that more effective therapy is needed to improve the prognosis of T-cell lymphomas.

Antibodies, Monoclonal↗
PubMed1985

Characterization of scrapie agent isolated from sheep in Japan.

A pathogenic agent isolated in mice from the brain of a sheep affected by scrapie-like disease was characterized. The incubation period of the disease in the primary transmission from the sheep to mice was longer than in the secondary and the tertiary transmission in the same strain of mice. Progressive dilution of the inoculum caused prolongation of the incubation period. The infectivity of the agent in a 10% brain homogenate persisted, but decreased about 10(3) to 10(4) times after heating at 100 C for 30 min. Histological changes in the diseased mouse brains consisted of vacuolation of the nerve cells and spongiform degeneration in the gray matter of the central nervous system. Fine rod-shaped granulae with a length of 3 to 5 nm were observed within the swollen neuropil, axon, and perivascular astrocytic process. No serum antibodies against available mouse viruses, parainfluenza type 1 virus, lymphocytic choriomeningitis virus, and mouse reovirus type 3, were detected in any mice used in the experiments. These findings demonstrate that the disease of the sheep was the first case of scrapie in Japan.

Animals↗