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Biomedical subjects

T Kubo

Publications and source records attributed to T Kubo.

At least 595 records · Page 33Linked to original sources

M13 bacteriophage DNA inhibits duck hepatitis B virus during acute infection.

We investigated effects of various DNAs on duck hepatitis B virus replication in vivo. One-day-old ducks were infected intravenously with DHBV. Various DNAs were then injected intravenously, and duck hepatitis B virus levels were followed for up to 20 days after the inoculation. When M13 bacteriophage DNA (M13 DNA), heat-denatured Escherichia coli DNA or phi X 174 phage DNA was injected intravenously at a dose of 2.45 mg/kg body wt daily for 10 days, a significant decrease of serum duck hepatitis B virus DNA was detected within 10 days. The efficacy was twice that reported with antisense DNA on a weight basis and far more than that reported on a molar basis. M13 DNA was superior, on the basis of effective dose, to acyclovir as an anti-duck hepatitis B virus agent. On treatment with M13 DNA, serum 2-5 A synthetase level was increased five to six times, suggesting that the antiviral effect of M13 DNA is at least partly due to induction of endogenous interferon, which in turn induces 2-5 A synthetase. No significant inhibitory effect on replication of duck hepatitis B virus was demonstrated by DNAs obtained from herring testes, herring sperm, salmon testes, human placenta or calf thymus. On discontinuation of M13 DNA injection on day 10, duck hepatitis B virus reappeared in the serum at later time points. Digestion of M13 DNA with S1 nuclease resulted in marked reduction of antiviral activity. These results show that M13 DNA, not its digested product, has potent antiviral activity.

2',5'-Oligoadenylate Synthetase↗

[A case of renal liposarcoma].

A-48-year-old male was admitted to our hospital with a right renal tumor. He received radical nephrectomy immediately. Histological examination of surgical specimen revealed renal liposarcoma, which consisted of mixed type of pleomorphic and well differentiated subtypes. Multiple tumorous lesions were scattered in the renal parenchyma. He has been alive without disease for 2 years and 7 months after surgery. Only 23 cases of renal liposarcoma have been reported in Japan.

Humans↗

N-methyl-D-aspartate receptors but not non-N-methyl-D-aspartate receptors mediate hypertension induced by carotid body chemoreceptor stimulation in the rostral ventrolateral medulla of the rat.

In urethane-anesthetized rats, excitatory amino acid antagonists were microinjected into the rostral ventrolateral medulla (RVLM) and their effects on the pressor response and tachycardia evoked by carotid chemoreceptor stimulation were examined. Microinjections of the N-methyl-D-aspartate (NMDA) receptor antagonists 2-amino-5-phosphonovalerate (AP5) and MK-801 into the RVLM inhibited these chemoreceptor reflex responses whereas these responses were not affected by injection of the non-NMDA receptor antagonist CNQX. AP5 and MK-801 but not CNQX abolished the pressor response evoked by NMDA whereas CNQX but not AP5 and MK-801 abolished that evoked by AMPA or kainate. These results provide evidence that NMDA receptors in the RVLM of the rat are involved in the carotid chemoreceptor reflex.

Animals↗

Refolding of yeast enolase in the presence of the chaperonin GroE. The nucleotide specificity of GroE and the role of GroES.

GroE, a chaperonin protein from Escherichia coli, facilitates the folding of numerous proteins by binding to protein-folding intermediates and suppressing aggregation (Gething, M., and Sambrook, J. (1992) Nature 355, 33-45). The specific mechanism of GroE-facilitated folding involves numerous interactions between GroEL, GroES, the refolding protein, and ATP. In the present study, we have probed the molecular characteristics of the refolding reaction of yeast enolase in the presence of GroE. We have found that (a) GroEL interacts specifically with enolase during the folding reaction, resulting in folding arrest; (b) the release of partially folded molecules of enolase from the GroE complex may be mediated by the addition of nucleotides other than ATP (ADP, CTP, and UTP); and (c) GroES is required for enolase to be released from GroEL in the presence of ADP, CTP, and UTP but not required in the presence of ATP. The nucleotide binding mechanism of GroEL and the specific role of GroES during the refolding reaction are discussed in detail.

Adenosine Triphosphate↗

Neonatal glutamate can destroy the hippocampal CA1 structure and impair discrimination learning in rats.

Neonatal Wistar rats were subcutaneously injected with 0.1, 1, or 2 mg/g b.wt. of monosodium glutamate (MSG) at 1, 3, 5, 7, and 9 days after birth. The animals were observed for degeneration of pyramidal cells in the hippocampus. The histological change disappeared when the animals were concurrently injected with glutamate diethyl ester (GDEE), an antagonist of the glutamate receptor. When light-dark discrimination learning was carried out at 10 weeks old, the correct response in the acquisition period was impaired in the animals given 1 and 2 mg/g of neonatal MSG. Their retention scores were also impaired in comparison with the control animal. The behavioral impairment recovered with pre-treatment with GDEE. No significant changes were observed in the concentrations of transmitter substances, including amino acids and monoamines. These results suggest that neonatal MSG destroys the hippocampus and impairs acquisition and retention of discrimination learning through the mechanism of glutamate receptors.

Animals↗

Transient appearance and localization of a 26-kDa lectin, a novel member of the Periplaneta lectin family, in regenerating cockroach leg.

A lectin consisting of a 26-kDa subunit was purified from the hemolymph of adult American cockroaches (Periplaneta americana) and shown to be a member of the Periplaneta lectin family. Immunoblotting analysis revealed that this lectin appeared transiently in regenerating legs after nymphal legs were amputated. Thus, its mode of appearance was similar to that of regenectin, another member of the Periplaneta lectin family. However, its time of appearance and localization in the regenerates were different from those of regenectin: the 26-kDa lectin appeared in regenerates in the middle stage of regeneration and was localized in the vicinity of the outside of newly formed epidermal cells. These results suggest that this lectin participates in the organization or stabilization of the epidermis during leg regeneration.

Animals↗

Involvement of both GABAA and GABAB receptors in tonic inhibitory control of blood pressure at the rostral ventrolateral medulla of the rat.

The rostral ventrolateral medulla (RVLM) contains vasopressor neurons which increase vasomotor tone. Endogenous GABA is suggested to be involved in mediation of the tonic inhibition of vasopressor neurons in the RVLM. To obtain more precise information about GABAergic mechanisms in the RVLM, we microinjected GABA agonists and antagonists unilaterally into the RVLM and examined their effects on blood pressure and heart rate. In addition, involvement of the other inhibitory amino acids glycine, beta-alanine and taurine in blood pressure regulation in the rat RVLM was also investigated. Male Wistar rats were anesthetized with urethane, paralyzed and artificially ventilated. The GABAA agonist muscimol (3-30 pmol) and the GABAB agonist baclofen (10-100 pmol) microinjected into the RVLM produced a decrease in blood pressure. The GABAA antagonist bicuculline (300 pmol) abolished the depressor response to muscimol (10 pmol) but not to baclofen (30 pmol) whereas the GABAB antagonist 2-hydroxysaclofen (1 nmol) abolished the depressor response to baclofen (30 pmol) but not to muscimol (10 pmol). Either bicuculline or 2-hydroxysaclofen alone produced a pressor response. Both antagonists inhibited depressor responses to nipecotic acid (7.7 nmol) and GABA (0.3 nmol). Glycine (0.13-4.0 nmol), beta-alanine (0.11-3.4 nmol) and taurine (0.08-2.4 nmol) microinjected into the RVLM also produced decreases in blood pressure. The glycine antagonist strychnine (0.58 nmol) abolished the depressor response to glycine, beta-alanine and taurine but not to GABA. The taurine antagonist 6-aminomethyl-3-methyl-4H-1,2,4-benzothiadiazine-1,1-dioxide) (1.3 nmol) inhibited the depressor response to beta-alanine and taurine but not to glycine and GABA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effects of morphine on release of acetylcholine in the rat striatum: an in vivo microdialysis study.

We examined the effect of morphine on the release of acetylcholine (ACh) in the striatum of freely moving rats using the in vivo microdialysis method. The basal level of ACh was 3.01 +/- 0.51 pmol/30 microliters/15 min in the presence of neostigmine (10 microM). Tetrodotoxin (1 microM), a selective blocker of voltage-dependent Na+ channels, rapidly decreased the release of ACh in the striatal perfusates. Morphine at a dose of 10 mg/kg (i.p.) caused a reduction of ACh release in the striatum at 90-150 min. However, a lower dose of morphine (5 mg/kg, i.p.) did not affect ACh release in the striatum. The reduction following intraperitoneal administration of morphine was abolished by naloxone (1.0 mg/kg). After microinjection of the neurotoxin 6-hydroxydopamine (6 micrograms/3 microliters, 7 days before) in the substantia nigra, the morphine (10 mg/kg)-induced decrease of ACh was attenuated, and a similar result occurred following reserpine (2 mg/kg, i.p.) 24 h before combined with alpha-methyl-p-tyrosine (300 mg/kg, i.p.) 2.5 h before. These findings indicate that morphine exerts an inhibitory influence on striatal ACh release in freely moving rats and that this inhibitory effect is mediated by the nigro-striatal dopaminergic system.

Acetylcholine↗

Fetal nucleated cells in maternal peripheral blood: frequency and relationship to gestational age.

To determine the frequency of fetal nucleated cells in maternal peripheral blood during different stages of pregnancy, 50 primigravidas were investigated by determining the frequency of cells with the Y chromosome using fluorescence in situ hybridization (FISH) of Y-specific repetitive sequences of the DYZ1 family. Polymerase chain reaction (PCR) amplifying the same part of the DYZ1 used as the probe in FISH and a single-copy Y-specific fragment was also carried out for genomic DNA from the same samples. Cells with the hybridization signal were detected by FISH at and after 15 weeks of pregnancy in all pregnant women who gave birth to boys. The ratio of cells with the signal to those without the signal ranged from 1 in 144,000 to 1 in 4,000 with a tendency to increase as the pregnancy advanced. The frequency of fetal cells estimated by the PCR experiments was significantly and positively correlated with that found by FISH. The present study suggests that fetal nucleated cells increase in maternal peripheral blood with advancing gestation, from less than 1 in 100,000 nucleated cells in the first trimester to around 1 in 10,000 at term. These frequencies were much lower than those reported by cytological methods.

Blood Cell Count↗

The sugar beet mitochondrial genome contains an ORF sharing sequence homology with the gene for the 30 kDa subunit of bovine mitochondrial complex I.

From a sugar beet mitochondrial DNA library, we have isolated an open reading frame (ORF192) showing extensive homology to the gene for the 30 kDa subunit of the bovine mitochondrial complex I (NADH: ubiquinone reductase). The ORF192 was found to be actively transcribed to give an RNA of approximately 1.0 kb. We have designated this gene nad9. Transcripts from the nad9 locus are edited by five C to U transitions, increasing similarity with the amino acid sequence of the corresponding bovine and Neurospora crassa polypeptides. Southern blot hybridization also indicates that nad9 is present in the mitochondrial genomes of a variety of higher plant species.

Amino Acid Sequence↗

Dynamical monitoring network system for perinatal care.

A new type of monitoring network system for perinatal care is proposed and has been developed. The patient monitoring system and data analyzing system are connected by a local area network (LAN). The doctor can retrieve past sampled data and results of data analysis, and make a detailed analysis at the same time that the patient is being monitored. The mainframe of the hospital information system (HIS) is connected with a data server in the perinatal care area via LAN. The database in perinatal care is supplied to the HIS and the doctor through this monitoring network system. If data sampled at maternity clinics or hospitals are once transmitted to the data server on LAN via the public telephone circuit, these data are available for the specialists on LAN. This function is utilized for supporting the obstetricians.

Computer Systems↗

Changes in preproenkephalin mRNA after unilateral and bilateral labyrinthectomy in the rat medial vestibular nucleus.

We examined the expression of preproenkephalin (PPE) mRNA in the vestibular nuclei in rats using in situ hybridization histochemistry. In normal rats, PPE mRNA-positive cells were observed in the medial and spinal vestibular nuclei. After unilateral labyrinthectomy, PPE mRNA was increased in the medial vestibular nucleus on the operated side from the 1st through the 3rd day after the surgery. It is suggested that the changes in PPE mRNA level after labyrinthectomy are involved in vestibular compensation.

Animals↗