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Biomedical subjects

K Noguchi

Publications and source records attributed to K Noguchi.

At least 271 records · Page 15Linked to original sources
PubMed1994

An illusion of velocity in motion perception.

We report a phenomenon that seems to have potential to elucidate a role of eye movement in motion perception. When tracking a target controlled by a triangular wave, the viewer perceives movement of the target like a ball bouncing in between two walls. We measured eye movement with electrooculograms (EOGs) when the subject was tracking a target controlled by a triangular wave. Eye movement after passing the turning point and rapidly returning to the target with saccadic movement and then smoothly tracking the target was recorded for all 4 adults. It was considered that extraretinal information on eye position during saccade may mainly contribute to this illusion.

Acceleration↗
PubMed1994

MR of acute subarachnoid hemorrhage: a preliminary report of fluid-attenuated inversion-recovery pulse sequences.

We report preliminary results applying fluid-attenuated inversion-recovery (FLAIR) sequences to three patients with acute subarachnoid hemorrhage. Acute subarachnoid hemorrhage could be clearly demonstrated as areas of high signal intensity on FLAIR sequences in all patients. These preliminary results suggest that with FLAIR sequences one could reliably diagnose acute subarachnoid hemorrhage.

Acute Disease↗
PubMed1994

[Clinical effect of arbekacin on MRSA infections after gastrointestinal surgery].

From January 1991 to July 1993, 58 patients with MRSA infections in our clinic at Wakayama Medical College and six affiliated hospitals were administered with arbekacin (ABK). The clinical results were as follows: 1. The clinical efficacy rates of ABK were 84% in pneumonia, 100% in both wound infections and hepatobiliary tract infections, and 85% in total. The bacteriological efficacy rate was 83%. 2. Regarding the administration route, the clinical efficacy rates were 60-79% by the intravenous treatment and inhalation therapy. Especially by the local administration with ABK, MRSA was eradicated in all cases. 3. The sufficient efficacy was obtained by the treatment of ABK alone (89%) and by the combined treatment with ABK (82%) and another antibiotics. From these results, it is concluded that ABK is useful for the treatment of MRSA infections after gastrointestinal surgery.

Administration, Inhalation↗
PubMed1993

Tau protein kinase I is essential for amyloid beta-protein-induced neurotoxicity.

Pathological changes of Alzheimer disease are characterized by cerebral cortical atrophy as a result of degeneration and loss of neurons. Typical histological lesions include numerous senile plaques composed of deposits of amyloid beta-protein and neurofibrillary tangles consisting predominantly of ubiquitin and highly phosphorylated tau proteins. Previously, tau protein kinase I (TPK I) was purified and its cDNA was cloned. To examine the biological role of this enzyme in neurons, we have studied the induction of its kinase activity in primary cultures of embryonic rat hippocampal neurons. Treatment of cultures with amyloid beta-protein significantly increased TPK I activity and induced the appearance of tau proteins recognized by the Alz-50 monoclonal antibody. In addition, though amyloid beta-protein was neurotoxic, either cycloheximide or actinomycin D prevented neuronal death. Death was also prevented by TPK I antisense oligonucleotides but not by sense oligonucleotides. These observations suggest that rat hippocampal neurons undergo programmed cell death in response to amyloid beta-protein and that TPK I is a key enzyme in this process.

Amyloid beta-Peptides↗
PubMed1993

Molecular cloning and characterization of the complementary DNA for the M(r) 85,000 protein overexpressed in adriamycin-resistant human tumor cells.

An M(r) 85,000 membrane protein was identified by a monoclonal antibody MRK20 raised against an Adriamycin-resistant subline of human myelogenous leukemia K562 (K562/ADM) cells. The M(r) 85,000 protein was found to be overexpressed in both innate and acquired Adriamycin-resistant tumor lines. A complementary DNA (cDNA) clone coding for the M(r) 85,000 protein was isolated by mixed oligonucleotide-primed polymerase chain reaction and further screening of a cDNA library from K562/ADM. Amino acid and nucleotide sequence analysis of the M(r) 85,000 protein revealed that this protein is identical with CD36, a cell surface adhesion molecule of endothelium, platelets, and monocytes. We constructed an expression vector utilizing two different promoters, SV40 and MMTV, and two cDNAs for the M(r) 85,000 protein that have different 3'-ends. DNA transfection experiments were carried out by the calcium phosphate method with a selectable marker using drug-sensitive human tumor lines KB3-1 and A2780 as recipient cells. We obtained transfectant clones expressing the M(r) 85,000 protein stably or inducibly but found no resistance against Adriamycin or vincristine. Direct selection with Adriamycin or vincristine or tumor cells transfected with the SV40 promoter-regulated expression constructs also failed to yield drug-resistant clones. These results indicate that the M(r) 85,000 protein/CD36 cannot confer drug resistance by itself, even though the protein can be an effective marker for Adriamycin resistance.

Amino Acid Sequence↗
PubMed1993

Mixed haplotype A beta Z/A alpha d class II molecule in (NZB x NZW)F1 mice detected by T cell clones.

We have tried to demonstrate the existence of a mixed haplotype MHC class II molecule in (NZB x NZW)F1 (B/WF1) mice. When a large panel of keyhole limpet hemocyanin-specific T cell clones derived from B/WF1 mice was analyzed, several clones were shown to be restricted by a F1-specific A beta Z/A alpha d class II molecule. Autoreactive A beta Z/A alpha d-specific T cell clones were also obtained. The ability of the association and expression of A beta Z with A alpha d was confirmed by hybridoma and transfection experiments. Hybridoma cell lines created by fusion of NZW (H-2z) spleen cells with M12.C3 (a A beta d- variant cell line derived from M12.4.1 (H-2d) B lymphoma) cells expressed A beta Z determinants. Transfection of A beta Z genomic DNA to M12.C3 cells resulted in the expression of A beta Z determinants. These hybridoma cell lines and transfectants were able to stimulate A beta Z/A alpha d-specific T cell clones, suggesting the expression of A beta Z/A alpha d molecules on the cell surface. However, attempts to demonstrate the existence of mixed haplotype MHC class II molecules in B/WF1 mice by two-dimensional (nonequilibrium pH gradient gel electrophoresis/SDS-PAGE) gel electrophoresis analysis with the use of anti-class II mAb failed to demonstrate the existence of mixed haplotype A beta Z/A alpha d or A beta d/A alpha z class II molecules in B/WF1 mice. Analysis of mixture of TA beta Z cell and B/WF1 spleen cell lysates immunoprecipitated by anti-A beta Z mAb suggested that the amount of haplotype mixed A beta Z/A alpha d molecules in B/WF1 spleen cells is less than 1/10 that of haplotype matched A beta/A alpha pairs. Our results suggest that, although undetectable by biochemical analysis, small amounts of mixed haplotype A beta Z/A alpha d molecules exist in B/WF1 spleen cells. Also, T cell clones which recognize them exists in B/WF1 mice. Because autoimmune symptoms of B/WF1 mice are shown to be related to heterozygosity at the H-2 region, autoreactive T cell clones which recognize the mixed haplotype A beta Z/A alpha d class II molecule might be involved for the induction of autoimmunity in B/WF1 mice.

Animals↗
PubMed1993

Quantification of axotomy-induced alteration of neuropeptide mRNAs in dorsal root ganglion neurons with special reference to neuropeptide Y mRNA and the effects of neonatal capsaicin treatment.

Alteration in mRNA expression in dorsal root ganglia (DRG) neurons encoding 5 neuropeptides was quantitatively compared in normal rats and in those neonatally treated with capsaicin, a selective neurotoxin which destroys a subpopulation of DRG neurons with unmyelinated axons. Adult rats received a unilateral transection of the sciatic nerve and were killed 7 days later. Oligonucleotide probes specific for the genes encoding neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), galanin (GAL), somatostatin (SOM), and calcitonin gene-related peptide (CGRP) were used for in situ hybridization and RNA blot analysis. Following the nerve cut, RNA blot analysis demonstrated a dramatic induction of NPY, VIP, and GAL mRNA levels from the undetectable constitutive level of expression. Conversely, CGRP and SOM mRNAs, which are constitutively expressed, were reduced 55% and 70%, respectively, following the nerve cut. A unimodal size distribution for neurons expressing NPY mRNA was determined, with a mean cross-sectional area of 1700 microns2 representing 24.4% of DRG neurons ipsilateral to the nerve cut. Neurons expressing VIP mRNA were mainly small sized, with a cross-sectional area of approximately 700 microns2, while those expressing GAL mRNA were both small (approximately 700 microns2) and medium (approximately 1,300 microns2) sized. The percentages of neurons expressing VIP or GAL mRNA were 19.9% and 33.7%, respectively. In neonatal capsaicin-treated rats, there was a 10% reduction in neurons expressing NPY mRNA, a 37% reduction for VIP, and a 27% for GAL mRNA compared to vehicle-treated rats after nerve cut. Capsaicin-sensitive neurons comprised 37% of CGRP neurons and 83% of SOM neurons. These observations suggest that NPY is primarily induced in myelinated primary afferent neurons, while VIP and GAL mRNA induction occurs in a mixed population, a sizeable percentage of which has unmyelinated axons. Additionally, SOM mRNA expression is associated mainly with unmyelinated primary afferents.

Animals↗
PubMed1993

cDNA expression cloning of the 85-kDa protein overexpressed in adriamycin-resistant cells.

An 85-kDa cell surface protein recognized by monoclonal antibody MRK-20 was identified in adriamycin-resistant tumor cells. The expression of the 85-kDa protein has recently been reported to be associated with the differentiation of hematopoietic cells. However, the primary structure of the 85-kDa protein has not been determined. To clarify its primary structure, we carried out cDNA expression cloning of the 85-kDa protein with monoclonal antibody MRK-20. We found that the 85-kDa protein is identical to CD36 (GP VI), but at least two species of transcript exist in the tumor cells and one of these transcripts has a novel sequence at the 3'-region. The transcript with the novel sequence at the 3'-region was found to be expressed during the differentiation of hematopoietic cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Role of endothelin ETB receptors in bronchoconstrictor and vasoconstrictor responses in guinea-pigs.

In anesthetized and ventilated guinea-pigs, intravenous injections of endothelin (ET)-1 (0.5 nmol/kg), ET-3 (0.5 nmol/kg), and [Ala1,3,11,15]ET-1 (20 nmol/kg), an ETB-selective receptor agonist, induced bronchoconstrictor and transient vasoconstrictor responses. Only the ET-1-induced transient vasoconstriction was followed by a secondary sustained pressor response. The ETA-selective receptor antagonist, BQ-123 (1 mg/kg i.v.), attenuated only the sustained pressor response. These results indicate that the bronchoconstrictor and transient vasoconstrictor responses to endothelins in guinea-pigs are mediated by ETB receptors, whilst the sustained pressor response is mediated by ETA receptors. The thromboxane A2 receptor antagonist, L-670,596 (0.5 mg/kg, i.v.) and a high dose of BQ-123 (30 mg/kg i.v.) abolished the bronchoconstriction only without affecting the transient pressor response to endothelin isopeptides. These results suggest that the ETB-mediated bronchoconstriction depends on thromboxane A2 formation. The different sensitivity of these ETB-mediated transient responses to BQ-123 suggests the possible existence of distinct ETB receptor subtypes.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1993

Expression of carcinoembryonic antigen in fresh human gastric cancer cells assessed by flow cytometry.

The expression of carcinoembryonic antigen (CEA) by tumor cells from freshly excised human gastric cancers was investigated using flow cytometry (FCM). Highly purified fresh human cancer cells were obtained from solid tumors in 20 patients and from malignant ascites in 6 patients. Thirteen of the 26 tumors were positive for CEA by FCM. CEA expression was more common in well-differentiated tumors than in poorly differentiated tumors. CEA expression was investigated by both FCM and immunohistochemistry in 9 patients, and the two methods agreed in 8 of them. However, quantitative evaluation of CEA expression could only be performed by FCM and not by immunohistochemical staining. FCM could analyze the expression of CEA not only on the cell membrane but also in the cytoplasm, by using gastric cancer cells with or without Triton X-100 treatment. Thus, this study showed that CEA expression can be determined and evaluated quantitatively by FCM.

Aged↗
PubMed1993

Essential role of myosin S-2 region in muscle contraction.

We studied the contraction characteristics and Mg-ATPase activity of glycerinated rabbit psoas muscle fibers in the presence and absence of polyclonal antibody directed against the subfragment-2 (S-2) region of myosin, to give information about the role of myosin hinge region in muscle contraction. The antibody was kindly supplied to us from Professor Harrington's laboratory. The antibody-induced decrease of Ca(2+)-activated isometric force development was always accompanied by a parallel decrease of muscle fiber stiffness, so that the stiffness versus force relation remained the same by the antibody treatment. Force-velocity curves, obtained by applying ramp decreases in load from steady isometric force to zero, indicated that the antibody had no effect on the maximum shortening velocity and the shape of the force-velocity curve. Simultaneous measurements of Mg-ATPase activity and Ca(2+)-activated isometric force showed that Mg-ATPase activity of the fibers remained unchanged despite the antibody-induced decrease of isometric force even to zero. These results indicate that, if the antibody attaches to the S-2 region of myosin molecules, their heads still hydrolyze ATP without contributing to both muscle force generation and muscle fiber stiffness.

Animals↗
PubMed1993

Promoter analysis of the PHO81 gene encoding a 134 kDa protein bearing ankyrin repeats in the phosphatase regulon of Saccharomyces cerevisiae.

The PHO81 gene encoding one of the regulators of the phosphatase regulon in Saccharomyces cerevisiae was mapped 9.8 centimorgans distal from the ser2 locus on the right arm of chromosome VII. Determination of the nucleotide sequence of cloned PHO81 DNA revealed a 3537 bp open reading frame encoding a 134 kDa protein. This protein has six repeats of a 33-amino acid sequence homologous to the ankyrin repeat and an asparagine-rich region. Transcription of PHO81 is activated by Pho4 protein in cooperation with Pho2 (i.e., Bas2/Grf10) protein under the influence of the inorganic phosphate (Pi) concentration in the medium, through the PHO regulatory system. Major transcription initiation sites of PHO81, determined by primer extension analysis, are at nucleotide positions -66 and -65 relative to the ATG codon. Deletion analysis showed that a 95 bp region from nucleotide position -385 to -291 is essential for response to the Pi signals. Purified Pho4 protein protected a 19 bp region (positions -350 to -332) in the 95 bp fragment from DNase I digestion in vitro and the protected region includes the core sequence 5'-CACGTG-3', which is also observed in other genes of phosphate metabolism.

Acid Phosphatase↗
PubMed1993

Stress-induced c-fos expression in the rat brain: activation mechanism of sympathetic pathway.

To clarify which brain regions are activated by stress, we used expression of the proto-oncogene, c-fos, as a marker. An increased number of neurons expressing Fos-like immunoreactivity in their nuclei was observed in discrete brain regions, such as the lateral septum, midline nuclei of the thalamus, paraventricular hypothalamic nucleus, brain stem catecholaminergic, and serotonergic neurons, in response to pain or immobilization stress. Distribution patterns of Fos-like immunoreactive neurons were quite similar in animals subjected to pain or immobilization. Whether or not neurons projecting to the spinal cord to activate the sympathetic pathway express Fos-like immunoreactivity was examined by means of fluorescent double-labeling using fluoro-gold (FG) as a tracer. In the PVH, Fos-immunoreactive neurons were localized in the dorsal medial parvocellular part, although those projecting to the spinal cord were localized dorsally and ventrally. Less than 1% of Fos-positive neurons in this nucleus was colocalized with FG. Among fos-like immunoreactive catecholaminergic and serotonergic neurons in the brain stem, those in the A5 region and raphe pallidus projected to the spinal cord.

Animals↗
PubMed1993

Effects of adrenergic stimulants on the splenic diameter, haemoglobin content and haematocrit in anaesthetized dogs: determination of the adrenoceptor subtype responsible for changes in the splenic diameter.

Changes in splenic diameter measured by sonomicrometry in response to various adrenergic stimulants were estimated together with simultaneously measured arterial haemoglobin content (HGB) and haematocrit (HCT) in anaesthetized dogs. Splenic diameter decreased following intravenous injections (i.v.) of adrenaline, noradrenaline and phenylephrine and splenic nerve stimulation associated with increases in arterial HGB and HCT, which were significantly attenuated by prazosin i.v. After prazosin i.v., adrenaline i.v. increased splenic diameter significantly, but noradrenaline i.v. did not. Isoprenaline i.v. increased splenic diameter transiently, followed by a decrease that was abolished by prazosin i.v. During occlusion of splenic arteries and veins, adrenaline i.v. and phenylephrine i.v. did not cause any change in arterial HGB and HCT. Injection to splenic artery (i.a.) of phenylephrine induced a significant decrease in splenic diameter that was attenuated by prazosin i.a. but not by yohimbine i.a. Clonidine i.a. did not change splenic diameter. The present results indicate that splenic contraction, which is mediated through alpha 1-adrenoceptor activation, causes a significant increase in arterial HGB and HCT.

Anesthesia↗
PubMed1993

Effects of intraduodenal administration of "kyushin," a senso (toad venom)-containing drug, on systemic hemodynamics, cardiacfunction and myocardial oxygen consumption in anesthetized dogs.

The effects of "Kyushin" (KY), a Senso (toad venom)-containing drug, on the cardiovascular system were examined by intraduodenal administration of KY in anesthetized open-chest dogs. KY (3 or 10 mg/kg) dose-dependently increased the peak positive first derivative of left ventricular pressure ((+)LVdP/dt) and mean aortic pressure, and decreased the left ventricular end-diastolic pressure (LVEDP). Myocardial oxygen consumption (MVO2) and heart rate (HR) were not significantly influenced by KY. KY produced a cardiotonic effect without any increase in MVO2, because the increase in MVO2 due to the cardiotonic effect of KY may have been cancelled by a decrease in MVO2 due to reduction of preload and the lack of increase in HR. In order to clarify the relationship between the cardiovascular effects of KY and the drug concentration in plasma, the concentration of anti-bufalin IgG reactive substance (BRS) in plasma was measured by enzyme immunoassay. The maximum BRS concentrations 20 min after administration of 3 and 10 mg/kg KY were dose-dependent. From the relationship between changes in (+)LVdP/dt and changes in BRS concentration after administration of KY, it is inferred that the effective concentration of BRS in plasma at which KY produces a cardiotonic effect in dogs is approximately 2-3 ng/ml.

Anesthesia↗