Search PubMed⌕ Search

Biomedical subjects

H Morisaki

Publications and source records attributed to H Morisaki.

At least 55 records · Page 3Linked to original sources
PubMed1998

Control of AMP deaminase 1 binding to myosin heavy chain.

AMP deaminase (AMPD) plays a central role in preserving the adenylate energy charge in myocytes following exercise and in producing intermediates for the citric acid cycle in muscle. Prior studies have demonstrated that AMPD1 binds to myosin heavy chain (MHC) in vitro; binding to the myofibril varies with the state of muscle contraction in vivo, and binding of AMPD1 to MHC is required for activation of this enzyme in myocytes. The present study has identified three domains in AMPD1 that influence binding of this enzyme to MHC using a cotransfection model that permits assessment of mutations introduced into the AMPD1 peptide. One domain that encompasses residues 178-333 of this 727-amino acid peptide is essential for binding of AMPD1 to MHC. This region of AMPD1 shares sequence similarity with several regions of titin, another MHC binding protein. Two additional domains regulate binding of this peptide to MHC in response to intracellular and extracellular signals. A nucleotide binding site, which is located at residues 660-674, controls binding of AMPD1 to MHC in response to changes in intracellular ATP concentration. Deletion analyses demonstrate that the amino-terminal 65 residues of AMPD1 play a critical role in modulating the sensitivity to ATP-induced inhibition of MHC binding. Alternative splicing of the AMPD1 gene product, which alters the sequence of residues 8-12, produces two AMPD1 isoforms that exhibit different MHC binding properties in the presence of ATP. These findings are discussed in the context of the various roles proposed for AMPD in energy production in the myocyte.

AMP Deaminase↗
PubMed1997

Cell cycle-dependent phosphorylation of p27 cyclin-dependent kinase (Cdk) inhibitor by cyclin E/Cdk2.

The cyclin-dependent kinase (Cdk) inhibitor p27 interrupts progression of the cell cycle by inhibiting various cyclin/Cdk activities. Since the protein level of p27 does not correlate with its mRNA level or protein synthesis rate in most cases, it is suggested that degradation of the protein may be regulated via an unidentified mechanism(s) involving a post-translational modification(s). We present evidence here that p27 phosphorylation is cell cycle-dependent and peaks in the late G1 phase and that the level of p27 protein is inversely correlated with its phosphorylation. Although both cyclin D1- and cyclin-E-dependent kinases are active in the late G1 phase in human fibroblasts, cyclin E/Cdk2 specifically phosphorylates p27 on threonine-187 in vitro. Interestingly, ectopic expression of T187A revealed that it was far more stable in vivo than wild type p27. Thus, phosphorylation of p27 by cyclin E/ Cdk2 may affect the stability of its protein and play a role in how the protein functions.

Amino Acid Substitution↗
PubMed1997

Structure and conformational changes in NSF and its membrane receptor complexes visualized by quick-freeze/deep-etch electron microscopy.

Using quick-freeze/deep-etch electron microscopy of recombinant proteins adsorbed to mica, we show that NSF, the oligomeric ATPase involved in membrane fusion, is a hollow 10 x 16 nm cylinder whose conformation depends upon nucleotide binding. Depleted of nucleotide, NSF converts to a "splayed" protease-sensitive conformation that reveals its subunit composition. NSF's synaptic membrane substrate, the ternary SNARE complex containing syntaxin, SNAP-25, and synaptobrevin, is a 4 x 14 nm rod with a "tail" at one end, corresponding to the N-terminus of syntaxin. Using epitope tags, antibodies, and maltose-binding protein markers, we find that syntaxin and synaptobrevin are aligned in parallel in the complex, with their membrane anchors located at the same end of the rod. This SNARE rod binds with alpha-SNAP to one end of the NSF cylinder to form an asymmetric "20S" complex. Together, these images suggest how NSF could dissociate the SNARE complex and how association and dissociation of the complex could be related to membrane fusion.

Adenosine Triphosphatases↗
PubMed1997

Cloning and expression of cDNA encoding heart-type isoform of AMP deaminase.

Mouse cDNA for the heart-type (H) isoform of AMP deaminase (EC 3.5.4.6., AMPD) has been isolated and characterized. The cDNA for the Ampd gene expressed in heart is predicted to encode a peptide of 766 amino acids with a molecular mass of 88 kDa. The coding region of this cDNA was quite homologous to the human AMPD3 gene which encodes the erythrocyte-type (E) isoform of AMPD, although the H-isoform of rodent AMPD was reported to be immunologically distinct from the E-isoform of human AMPD. The non-coding region of the isolated cDNA is not homologous to human AMPD3, while rodent Ampd1 has similarity to human AMPD1 in the non-coding region as well as in the coding region. The transcripts for the cloned cDNA were expressed in heart, slow-twitch skeletal muscle and non-muscle tissues. Prokaryotic expression showed that this cDNA encodes a catalytically active enzyme which reacts to the specific antibody raised to the H-isoform of AMPD.

AMP Deaminase↗
PubMed1997

New p57KIP2 mutations in Beckwith-Wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is characterized by numerous growth abnormalities and an increased risk of childhood tumors. The gene for BWS is localized in the 11p15.5 region, as determined by linkage analysis of autosomal dominant pedigrees. The increased maternal transmission pattern seen in the autosomal dominant-type pedigrees and the findings of paternal uniparental disomy reported for a subgroup of patients indicate that the gene for BWS is imprinted. Previously, we found p57KIP2, which is a Cdk-kinase inhibitor located at 11p15, is mutated in two BWS patients. Here, we screened for the mutation of the gene in 15 BWS patients.

Austria↗
PubMed1997

A human urinary protease inhibitor (ulinastatin) inhibits neutrophil extracellular release of elastase during cardiopulmonary bypass.

OBJECTIVES: To determine the benefits of a human urinary protease inhibitor (ulinastatin) on postoperative pulmonary dysfunction associated with neutrophil activation during cardiopulmonary bypass. DESIGN: A prospective, randomized, clinical study. SETTING: The study was performed at Keio University Hospital, Tokyo. PARTICIPANTS: Eighteen adult patients scheduled for primary cardiac surgery. INTERVENTIONS: The patients were randomly assigned either to the control group (n = 8) or to the group (n = 10) receiving ulinastatin (600,000 U in total). MEASUREMENTS AND MAIN RESULTS: Human neutrophil ability to release elastase in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) in vitro was measured before and after cardiopulmonary bypass, together with plasma levels of neutrophil elastase complex, interleukin-B, and C3a. Intrapulmonary shunt fraction was then calculated. Neutrophil elastase release in response to fMLP significantly increased in the control group, but remained unchanged in the ulinastatin group. In addition, ulinastatin minimized the increase of plasma neutrophil elastase, independently of the production of interleukin-B or C3a. Simultaneously, ulinastatin ameliorated the increase of intrapulmonary shunt, which was correlated with extracellular elastase release. CONCLUSIONS: Ulinastatin attenuated the elevation of fMLP-induced elastase release, which was associated with the deterioration of gas exchange during cardiopulmonary bypass. The administration of this agent has a potential to lessen the risk of postperfusion lung injury.

Adult↗
PubMed1997

Mouse Mef2b gene: unique member of MEF2 gene family.

The myocyte enhancer factor 2 (MEF2) gene family, which belongs to the MADS [MCM1, agamous, deficiens, serum response factor (SRF)] superfamily, is thought to play an important role in differentiation of myocytes, including cardiomyocytes. To better understand the mouse Mef2 gene family, the mouse Mef2b gene, which was found to be expressed in undifferentiated embryonal cells, was characterized. The Mef2b gene was found to be more than 30 kb in length, consisting of 11 exons. Eight exons correspond to coding regions and the remaining 3 exons for the 5' part are alternatively used. Two internal exons are subject to alternative splicing, resulting in production of four subtypes of mouse MEF2B peptides. Fluorescence in situ hybridization (FISH) and inter-specific backcross analysis identified the Mef2b gene locus. Mef2b gene was expressed in heart or skeletal muscle of early mouse embryo, but not in those of adult mouse. Functionally, mouse MEF2B did not exhibit DNA binding with the MEF2 consensus element in vitro, but did cause transcriptional activation of the MEF2 element, although it was less effective than human MEF2B. Based on these results, mouse MEF2B seems to have a unique character, distinct from other MEF2 family members.

Amino Acid Sequence↗
PubMed1997

Leukocyte-endothelium interaction in the rat mesenteric microcirculation during halothane or sevoflurane anesthesia .

BACKGROUND: The effects of inhalational anesthetics on the microcirculation, including leukocyte dynamics, remain to be clarified. The authors investigated halothane and sevoflurane anesthesia to determine if these agents evoked leukocyte adhesion through endothelial cell-dependent mechanisms involving such adhesion molecules. METHODS: Rats were anesthetized with halothane or sevoflurane in 100% oxygen and the lungs were mechanically ventilated. Leukocyte behavior in mesenteric venules was recorded through intravital video microscopy under monitoring microvascular hemodynamics. To examine the mechanisms for leukocyte rolling and adhesion, these studies were repeated after animals were pretreated with a monoclonal antibody against P-selectin (MAb PB1.3) or against intracellular adhesion molecule-1 (ICAM-1; MAb 1A29): P-selectin required for rolling of circulating leukocytes and ICAM-1 for firm adhesive interactions with leukocyte integrins. RESULTS: Under baseline anesthetic conditions (1 minimum alveolar concentration [MAC]), venular wall shear rates, an index of the disperse force on marginating leukocytes, in the sevoflurane-treated rats were about two times higher than those with halothane. At 2 MAC, halothane caused a marked arteriolar constriction and decreasing shear rates concurrent with an increasing density of venular leukocyte adhesion. Sevoflurane at 2 MAC induced leukocyte rolling and adhesion, which were attenuated by PB1.3 and 1A29, without alterations in the wall shear rates. Halothane-induced leukocyte adhesion was not prevented by PB1.3 but it was by 1A29. CONCLUSIONS: Halothane or sevoflurane anesthesia induces venular leukocyte rolling and adhesion: P-selectin upregulation plays a crucial role in leukocyte rolling and adhesion during sevoflurane anesthesia, whereas low-flow perfusion is likely to evoke ICAM-1-dependent leukocyte adhesion during halothane anesthesia.

Anesthetics, Inhalation↗
PubMed1997

Cell-surface hydrophobicity and scum formation of Rhodococcus rhodochrous strains with different colonial morphologies.

Rhodococcus rhodochrous has been reported to be one of the micro-organisms responsible for the formation of scum which is thick and viscous biological foam in activated sludge plants. The hydrophobicity of mycolic acids present on the cell surface and the long-branched shape of the hyphae have been thought to contribute to the scum formation. Cell surface hydrophobicity and scum formation of four R. rhodochrous strains with different colony morphologies were determined, and the results showed that the two rough strains had strong cell surface hydrophobicity and produced scum, whereas the weakly hydrophobic smooth strain and the hydrophilic mucoidal strain did not. All four strains displayed long, branched hyphae, and their electrophoretic mobilities were similar, between pH 4 and 9. These data suggest that changes in the cell surface hydrophobicity of the R. rhodochrous result in changes in the culture characteristics and the formation of scum.

Bacterial Adhesion↗
PubMed1997

Mouse U2af1-rs1 is a neomorphic imprinted gene.

The mouse U2af1-rs1 gene is an endogenous imprinted gene on the proximal region of chromosome 11. This gene is transcribed exclusively from the unmethylated paternal allele, while the methylated maternal allele is silent. An analysis of genome structure of this gene revealed that the whole gene is located in an intron of the Murr1 gene. Although none of the three human U2af1-related genes have been mapped to chromosome 2, the human homolog of Murr1 is assigned to chromosome 2. The mouse Murr1 gene is transcribed biallelically, and therefore it is not imprinted in neonatal mice. Allele-specific methylation is limited to a region around U2af1-rs1 in an intron of Murr1. These results suggest that in chromosomal homology and genomic imprinting, the U2af1-rs1 gene is distinct from the genome region surrounding it. We have proposed the neomorphic origin of the U2af1-rs1 gene by retrotransposition and the particular mechanism of genomic imprinting of ectopic genes.

Adaptor Proteins, Signal Transducing↗
PubMed1997

[The effects on image instructions and spontaneous use of imagery on the self-control of skin temperature].

The aim of this study was to examine the effects of image instructions on subjects able to use imagery spontaneously and those unable to use them spontaneously, on the self-control of skin temperature. The subjects were 20 undergraduate students. All subjects were instructed to raise their skin temperatures through four sessions. After the first session, subjects were assigned to one of the following three groups: the spontaneous image group (SI), instructed image group (II), and control group (C). The SI group comprised only of those subjects who used imagery spontaneously in the first session. Before the second session, the subjects in the SI and II groups were instructed to use imagery in the following sessions. The results showed that SI group subjects could raise their skin temperatures to higher levels than those in the other groups. These results suggest that subjects who use imagery spontaneously have a greater ability to control their skin temperatures, than other subjects who cannot raise their skin temperatures well, even if instructed in the use of imagery.

Adult↗
PubMed1997

[Preventive use of diltiazem to suppress supraventricular tachyarrhythmia in the patients after esophagectomy].

We investigated the efficacy of preventive use of diltiazem to suppress supraventricular tachyarrhythmia such as paroxysmal atrial tachycardia (PAT) and atrial fibrillation (Af) in the patients who underwent transthoracic esophagectomy. We divided 52 patients into 2 groups; the diltiazem group (n = 26) and the control group (n = 26). In the diltiazem group continuous intravenous infusion of diltiazem (1-3mcg.kg-1.min-1) was started when the patient's heart rate remained over 110.min-1 without any predisposing factor. On the other hand, in the control group we did not use it preventively. In both groups, we did not restrict the use of antiarrhythmic agents if necessary. We recognized PAT or Af in the control group (54%) more often than in the diltiazem group (19%). PAT or Af seldom occurred after the 4th post-operative day in the both groups. Serum diltiazem concentrations of 9 patients after about 10 hours infusion showed great variation (between 30 and 250 ng.ml-1). In 7 of them the diltiazem concentration increased as the duration of infusion was prolonged. However, we did not observe bradyarrhythmia. We consider that the continuous diltiazem infusion is effective in suppressing supraventricular tachyarrhythmia after esophagectomy.

Aged↗
PubMed1996

Chromosomal assignment and imprinting tests for the mouse delta subunit of the cytosolic chaperonin containing TCP-1 (Cct4) gene to proximal chromosome 11.

The CCT (chaperonin containing TCP-1) complex functions as a molecular chaperone in the eukaryotic cytosol. This complex consists of several species of related polypeptides. The chromosomal localization of the mouse Cct4 gene encoding the delta subunit of CCT was assigned in this study to proximal chromosome 11 by genetic mapping. Restriction mapping analysis using YAC and pulse-field gel electrophoresis showed that Cct4 is located within a region about 300 kb from the imprinted gene U2af1-rs1. Expression of Cct4 was biallelic, and therefore Cct4 is not imprinted in neonatal mice. The localization of the human homologue of Cct4 on chromosome 2 corresponds well with the fact that homologues of other genes in the proximal region of mouse chromosome 11 also map to the region of conserved synteny in human chromosome 2.

Alleles↗
PubMed1996

Wound infiltration with lidocaine prolongs postoperative analgesia after haemorrhoidectomy with spinal anaesthesia.

PURPOSE: There are few clinical data examining whether sensitization of peripheral nerves contributes to postoperative pain when the entry of noxious impulses to the central nervous system is blocked. We hypothesized that wound infiltration with lidocaine would provide better postoperative analgesia than with normal saline following haemorrhoidectomy with spinal blockade. METHODS: In a randomized, placebo-controlled, blinded study, 168 adults undergoing haemorrhoidectomy were allocated to two groups. In Group L (n = 88) local infiltration was provided with lidocaine 1% and in Group S (n = 80) with normal saline. Following spinal anaesthesia with lidocaine 3%, the surgeon infiltrated 15 ml of either infiltration solution to the surgical area. Postoperative analgesia was obtained by continuous epidural administration of 90 mg eptazocine in normal saline for 48 hr. Supplemental analgesics were given on request. Postoperative pain control was assessed at rest and during coughing with a 10 cm VAS on the 1st, 2nd, and 3rd postoperative days (POD). RESULTS: The VAS scores at rest in Group L were lower than those in Group S throughout the postoperative period. During coughing, VAS scores in Group S were increased on the 3rd postoperative day, while those in Group L remained constant (4.42 +/- 0.27 vs 3.14 +/- 0.28, P < 0.05). Fewer patients in Group L than in Group S required supplemental analgesics. CONCLUSION: Preoperative lidocaine infiltration to the surgical area provided prolonged postoperative analgesia in patients receiving haemorrhoidectomy with spinal anaesthesia.

Adult↗
PubMed1996

An imprinted gene p57KIP2 is mutated in Beckwith-Wiedemann syndrome.

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin/Cdk complexes, and is a negative regulator of cell proliferation. The gene encoding p57KIP2 is located at 11p15.5 (ref. 2), a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome, a cancer-predisposing syndrome, making it a tumour-suppressor candidate. Several types of childhood tumours including Wilms' tumour, adrenocortical carcinoma and rhabdomyosarcoma exhibit a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting is involved. Genetic analysis of the Beckwith-Wiedemann syndrome indicated maternal carriers, as well as suggesting a role of genomic imprinting. Previously, we and others demonstrated that p57KIP2 is imprinted and that only the maternal allele is expressed in both mice and humans. Here we describe p57KIP2 mutations in patients with Beckwith-Wiedemann syndrome. Among nine patients we examined, two were heterozygous for different mutations in this gene-a missense mutation in the Cdk inhibitory domain resulting in loss of most of the protein, and a frameshift resulting in disruption of the QT domain. The missense mutation was transmitted from the patient's carrier mother, indicating that the expressed maternal allele was mutant and that the repressed paternal allele was normal. Consequently, little or no active p57KIP2 should exist and this probably causes the overgrowth in this BWS patient.

Beckwith-Wiedemann Syndrome↗
PubMed1996

Hyperdynamic sepsis depresses circulatory compensation to normovolemic anemia in conscious rats.

This study was designed to determine whether sepsis modifies the ability to preserve vital organ O2 delivery (QO2) across a clinically relevant range of hematocrits. Ninety rats were randomly allocated to cecal ligation and perforation (CLP) or a sham (Sham) procedure. With the use of rat plasma, rat whole blood, or packed rat red blood cells, respectively, randomization into three different hematocrit subgroups followed: low (21-28%), middle (33-40%), and high (45-52%). Organ blood flow values (Q) were measured by the radioactive microsphere technique, and organ QO2 values were calculated. Twenty-four hours after laparotomy, the hematocrit grouping had not modified the interorgan distribution of Q or QO2 in either the CLP or Sham rats. To characterize overall metabolic O2 reserve, rats were then exposed to hypoxia (inspired O2 fraction, 0.08) for 20 min. Whereas cardiac output increased significantly during hypoxia in all experimental groups, myocardial QO2 failed to increase in the low hematocrit Sham subgroup and fell significantly in both the middle- and low-hematocrit CLP subgroups. There was also a lesser redistribution of QO2 away from the small intestine in the low-hematocrit compared with the high-hematocrit CLP subgroup. We conclude that myocardial QO2 is more effectively maintained in septic hypoxic rats if the hematocrit is maintained at levels >45%.

Anemia↗