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Biomedical subjects

T Ishiguro

Publications and source records attributed to T Ishiguro.

At least 91 records · Page 5Linked to original sources
PubMed1996

Fluorescence detection of specific sequence of nucleic acids by oxazole yellow-linked oligonucleotides. Homogeneous quantitative monitoring of in vitro transcription.

We have developed a fluorescent DNA probe, oxazole yellow (YO)-linked oligonucleotide complementary to a target DNA/RNA, which can enhance the fluorescence on hybridizing with a target nucleotide. We demonstrated the applicability of the YO-linked oligonucleotide probe to real-time monitoring of the in vitro transcription process of a plasmid DNA constructed containing the 5'-terminus non-coded region of hepatitis C virus RNA. In the process of in vitro transcription in the presence of YO-linked complementary oligonucleotide, the fluorescence of the reaction mixture showed a time-dependent linear increase corresponding to the generated target RNA product.

Benzoxazoles↗
PubMed1996

Monoamine neurotransmitter function and spontaneous recurrence of methamphetamine psychosis.

The process that triggered spontaneous recurrence of methamphetamine (MAP)-induced paranoid-hallucinatory psychosis, a phenomenon known as flashbacks, was studied in 41 subjects with flashbacks, along with 84 subjects with a history of previous MAP psychosis but no flashbacks. Plasma levels of norepinephrine (NE), dopamine, and 5-hydroxytryptamine, and their respective metabolites were assayed in 28 of the 41 flashbackers, 16 of the 84 non-flashbackers, 9 subjects with persistent MAP psychosis, and 28 healthy controls comprised of 20 MAP users and 8 non-users. None of the 28 controls had become psychotic. The 41 flashbackers had experienced significantly greater frequencies of threatening events and frightening paranoid-hallucinatory states during previous MAP use than the 84 non-flashbackers. The dominant factor that triggered flashbacks was a mild fear of other persons. The 41 flashbackers may have encoded threatening experiences as frightening images. Repeated MAP use with threatening experiences may induce sensitization to frightening images. Plasma NE levels during flashbacks were significantly higher than the levels during periods of normalcy, and the NE levels in the 20 user and 8 non-user controls. The 9 subjects with persistent MAP psychosis had significant higher levels of NE than the user and non-user controls. The 16 non-flashbackers had significantly higher MHPG levels than the user controls. The findings suggest that MAP use may induce changes at pharmacological levels in the process underlying sensitization to frightening images. We suggested that when the flashbackers experienced a mild fear of other persons, MAP-induced sensitization to frightening images may have been actualized. Thus, the flashbacks may have been caused through increased noradrenergic hyperactivity.

Adult↗
PubMed1996

Plasma monoamine metabolites and spontaneous recurrence of methamphetamine-induced paranoid-hallucinatory psychosis: relation of noradrenergic activity to the occurrence of flashbacks.

The relationship between monoamine neurotransmitter function and spontaneous recurrence of methamphetamine (MAP) psychosis, a phenomenon known as flashbacks, was studied in a group of incarcerated women. Plasma levels of norepinephrine (NE), dopamine, 5-hydroxytryptamine, and their respective metabolites were assayed in 28 flashbackers, 19 non-flashbackers with a history of previous MAP psychosis, and 9 subjects with persistent MAP psychosis. Control data were available from 61 physically healthy prisoners (41 MAP users and 20 non-users, none of whom became psychotic). The plasma NE levels of the 28 flashbackers during flashbacks were significantly higher than levels during periods of normality, and were significantly higher than those in the MAP user and non-user controls. Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels during flashbacks were significantly higher than those in the user controls. The nine subjects with persistent MAP psychosis had significantly higher NE levels than the user and non-user controls. The 19 non-flashbackers had significantly higher MHPG levels than the user controls. Plasma levels of 3-methoxytyramine and dihydroxyphenylacetic acid contributed to the NE levels in the flashbackers, in contrast to the findings in the control group. Noradrenergic systems may be compromised in the flashbackers, suggesting increased vulnerability to psychotic decompensation. These findings suggest that aggravation in peripheral noradrenergic hyperactivity may be an important factor in the occurrence of flashbacks.

Adult↗
PubMed1996

Identification of genes differentially expressed in B16 murine melanoma sublines with different metastatic potentials.

B16-F10 and B16-BL6 are B16 mouse melanoma sublines that preferentially metastasize to the lung following i.v. and s.c. injections, respectively. To study molecular mechanisms underlying the different metastatic behaviors exhibited by the B16 melanoma sublines, we performed differential hybridization of the genes transcribed in these cells and compared their expression levels. We isolated four genes that were highly expressed in B16-F10 cells but not in B16-BL6 cells: TI-225 (polyubiquitin), TI-229 (pyruvate kinase), TI-241 (LRF-1 homologue), and TI-227 (novel gene). Triosephosphate isomerase, 10-formyltetrahydrofolate dehydrogenase, tyrosinase-related protein 2, cytochrome c oxidase, ATP synthetase alpha subunit, RNA helicase, and ribosomal protein (L37, J1, acidic phosphoprotein), however, showed higher expression in B16-BL6 cells than in B16-F10 cells. Among these clones, transfection of TI-241 into the low metastatic clone F1 converted the parental cells from low- into high-metastatic cells. TI-241 may regulate the expression of various genes as a transcription factor in the complex process of metastasis.

Amino Acid Sequence↗
PubMed1996

Antibody responses against Echinococcus multilocularis antigens in naturally infected Rattus norvegicus.

Two Norway rats, Rattus norvegicus, were found to be naturally infected with Echinococcus multilocularis in Japan. One of them was simultaneously infected with at least three different sized metacestodes of Taenia taeniaeformis. These two R. norvegicus rats and another R. norvegicus naturally infected with T. taeniaeformis and Capillaria hepatica were examined to see if they showed any antibody responses against these two cestode parasites with the view to obtaining more information on the importance of rats as the intermediate host for E. multilocularis. These R. norvegicus showed very poor antibody responses against the two cestode species, although the Wistar rats, R. rattus, experimentally infected with a single smaller sized metacestode of T. taeniaeformis showed stronger responses not only against T. taeniaeformis but also against E. multilocularis. Therefore the three R. norvegicus naturally infected with E. multilocularis and/or T. taeniaeformis demonstrated virtually no immune response, at least against these cestodes.

Animals↗
PubMed1996

237Np in hemp-palm leaves of Bontenchiku for fishing gear used by the Fifth Fukuryu-Maru: 40 years after "Bravo".

The alpha radioactive components in the Hemp-palm of Bontenchiku were determined with emphasis on the measurement low-level 237Np by alpha-ray spectrometry after chemical separation. Bontenchiku is a kind of fishing gear for long-line fishing used by the Fifth Fukuryu-Maru (Lucky Dragon). This gear was exposed to fallout from the second thermonuclear test explosion (Bravo) at Bikini Atoll in March 1954. The 237Np content in the Bontenchiku sample was determined to be 11.5 +/- 0.8 mBq g(-1), with an activity ratio of 237Np:239,240Pu and an atom ratio of 237Np:239Pu estimated to be (2.2 +/- 0.2) x 10(-3) and 0.42 +/- 0.04, respectively. The data showed the existence of a chain reaction of 238U and its ratio to be 237Np:239Pu, as well as the presence of 237U at the time of fallout from Bravo event in March 1954.

Neptunium↗
PubMed1996

A case of serotonin syndrome induced by concomitant treatment with low-dose trazodone and amitriptyline and lithium.

We describe a patient treated with trazodone, amitriptyline and lithium carbonate who developed anxiety, restlessness, tremor, myoclonus, hyperreflexia, diaphoresis, rigidity and hyperthermia. The constellation of findings was diagnostic of serotonin syndrome. Although doses of trazodone and amitriptyline were relatively low, serotonin syndrome developed in this patient. It is suggested that the combination with lithium facilitated the effect of central serotonergic responses mediated by trazodone and amitriptyline.

Amitriptyline↗
PubMed1996

Anesthesia induced in pigs by use of a combination of medetomidine, butorphanol, and ketamine and its reversal by administration of atipamezole.

OBJECTIVE: To develop an IM administrable anesthetic combination for pigs. DESIGN: Use of a combination of atropine, medetomidine, butorphanol, and ketamine (MB-K) was evaluated as an anesthetic regimen and compared with that of a combination of atropine, xylazine, butorphanol, and ketamine (XB-K). Cardiorespiratory effects of MB-K combination and use of atipamezole as a means of reversing anesthesia induced by MB-K were examined. ANIMALS: 18 castrated, mixed-breed, specific-pathogenfree pigs, aged 8 to 15 (mean, 12.1) weeks and weighing 14.5 to 26.0 (mean, 19.6) kg. were studied. PROCEDURE: Dosages of drugs used in this study were atropine, 25 micrograms/kg of body weight; medetomidine, 80 micrograms/kg; xylazine, 2 mg/kg; butorphanol, 200 micrograms/kg; ketamine, 10 mg/kg; and atipamezole, 240 micrograms/kg. RESULTS: MB-K combination proved to be more effective than XB-K combination as an anesthetic combination. After quick and smooth induction by IM administration, MB-K-induced anesthesia was sustained for 98.8 +/- 22.5 minutes (mean +/- SD, 47.4 +/- 16.5 minutes by XB-K) with accompanying muscular relaxation (91 +/- 18 minutes) and loss of pedal (82 +/- 24 minutes) and laryngeal (75 +/- 19 minutes) reflexes. Loss of these reflexes was of significantly longer duration than the loss induced by XB-K, enabled tracheal intubation, and, thus, supported major surgery for at least 30 minutes after induction. Recovery from MB-K-induced anesthesia was smooth. MB-K combination had a slight stimulative effect on cardiovascular status, and a significant depressant effect on blood gas and acid-base status, but these effects were within biologically acceptable limits. Oxygen consumption of pigs under MB-K-induced anesthesia decreased significantly. MB-K-induced anesthesia could be effectively and quickly reversed by IM or IV administration of atipamezole. CONCLUSIONS: The combination of medetomidine, butorphanol, and ketamine induces excellent surgical anesthesia in pigs, and results in moderate cardiorespiratory effects. A great advantage of the anesthetic regimen is that it can be effectively and quickly reversed by atipamezole. CLINICAL RELEVANCE: Medetomidine, butorphanol, and ketamine-induced anesthesia is available for short-term major surgery in pigs.

Adrenergic alpha-Antagonists↗
PubMed1995

Homogeneous quantitative assay of hepatitis C virus RNA by polymerase chain reaction in the presence of a fluorescent intercalater.

We have developed a homogeneous quantitative assay of DNA/RNA by performing PCR in the presence of an oxazole yellow derivative, a fluorescent DNA intercalative dye, and monitoring the fluorescence intensity of the PCR reaction mixture during PCR cycles. We have demonstrated the applicability of this assay by use it to quantify hepatitis C virus (HCV) RNA of serum samples from patients with chronic hepatitis C. This assay gave efficient and reproducible results in a clinically useful dynamic range below 10(-6) copies of HCV RNA for interferon therapy.

Base Sequence↗
PubMed1995

Reversible phosphorylation of both Tyr7 and Tyr10 in the alpha-chain of pig stomach H+,K(+)-ATPase by a membrane-bound kinase and a phosphatase.

When pig stomach membrane H+,K(+)-ATPase preparations were incubated with [gamma-32P]ATP and Mg2+ with vanadate, 32P was incorporated into the alpha-chain of H+,K(+)-ATPase to a steady-state level of approximately 0.7 mol of phosphotyrosine (Tyr(P))/mol of phosphoenzyme intermediates. The addition of a membrane H+,K(+)-ATPase preparation with Mg2+ accelerated the liberation of 32P from Tyr(P) residues in the alpha-chain. Mild tosylphenylalanyl chloromethyl ketone-trypsin treatment solubilized 32P-containing peptides from the alpha-chain almost completely. A reverse-phase column chromatography of the supernatant gave two peaks of 32P-peptide with similar total radioactivities. The amino acid sequence of both peaks was shown to be Gly-Lys-Ala-Glu-Asn-Tyr-Glu-Leu-Tyr-Gln--, which is consistent with the amino-terminal sequence of the alpha-chain of H+,K(+)-ATPase deduced from cDNA from pig stomach except that the initial Met was absent. The comparison of the recovery of amino acid from each Edman cycle showed that the phosphorylation of Tyr10 occurred preceding the phosphorylation of Tyr7. These data and others suggested the presence of a novel membrane-bound enzyme system to participate in reversible phosphorylation of both Tyr residues in the alpha-chain of H+,K(+)-ATPase.

Amino Acid Sequence↗
PubMed1995

Chemical restraint by medetomidine-ketamine and its cardiopulmonary effects in pigs.

Chemical restraint induced by medetomidine-ketamine (M-K) combination was evaluated compared with that by xylazine-ketamine (X-K) in pigs. The duration of restraint by M-K was 49.4 +/- 13.5 min (mean +/- SD) and longer than that by X-K (34.6 +/- 17.2 min), but the difference was not significant. The effect of X-K was not stable, since one of five pigs was restrained only for 6 min. Both combinations produced muscle relaxation. The duration of muscle relaxation in M-K was 43.6 +/- 12.7 min and was significantly longer than that in X-K (21.0 +/- 14.0 min). M-K combination had a slightly stimulative effect on the cardiovascular system, but scarcely changed the respiratory parameters. This limited effect on cardiopulmonary system was an advantage of M-K combination for chemical restraint in pigs. These results indicated that M-K combination is suitable for chemical restraint with prolonged muscle relaxation and has limited cardiopulmonary effects in pigs.

Anesthetics↗
PubMed1995

Pharmacological characteristics of the canine cerebrovascular constriction produced by neuropeptide Y.

In order to elucidate the role of neuropeptide Y (NPY) in cerebral circulation, we undertook the present study to examine the action of NPY itself, and the combined effects of NPY with other vasoconstrictor stimuli. NPY itself produced contractions of isolated canine basilar artery in a concentration-dependent manner, which was independent of the presence or absence of endothelium. C-terminal peptides of NPY (NPY12-36) and (NPY22-36) were weak agonists, while those without C-terminals were ineffective. The vasoconstriction produced by NPY was, however, strongly potentiated by increasing the K+ concentration in the medium up to 20 mM, or by pretreatment with tetraethylammonium, a K+ channel blocker and hemolysate containing oxyhemoglobin. NPY also augmented the contractile responses to prostaglandin F2 alpha, norepinephrine, and histamine, but not to serotonin. The contraction in response to NPY per se or in 20 mM K+ was effectively attenuated by Ca2+ antagonists such as d-cis-diltiazem, and in a Ca(2+)-free medium. These results suggest that in canine basilar artery, the activation of the Y1 receptor modulates the availability of the L-type Ca2+ channel, leading to enhance Ca2+ influx from the extracellular space and potentiate contractile effects of other cerebral vasoconstrictors. This might be involved in the cerebral vasospasm which occurs after subarachnoid hemorrhage.

Animals↗