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Biomedical subjects

T Kamiya

Publications and source records attributed to T Kamiya.

At least 55 records · Page 3Linked to original sources
PubMed2000

Heart rate recovery after exercise and cardiac autonomic nervous activity in children.

To investigate the difference in heart rate (HR) recovery after exercise between children and young adults, we administered a constant load of light exercise intensity and progressive treadmill exercise tests to nine children (aged 9 to 12 y, group A) and eight young adults (six male and two female, aged 17 to 21 y, group B) who had a history of Kawasaki disease without significant coronary arterial lesions. HR after both exercise protocols was analyzed. The low-frequency (LF) and high-frequency (HF) components of HR variability were measured, and LF/HF was calculated (log LF, log HF, log L/H). Arterial baroreflex sensitivity was assessed by the phenylephrine method. There were no differences between groups A and B in resting HR, peak HR, peak oxygen uptake, and decreases in systolic blood pressure during the recovery period. HR 1 and 2 min after peak exercise and 1 min after constant-load exercise was significantly lower in group A than in group B (p < 0.05), and the changes in HR from peak values after both exercise tests were also greater in group A than in group B (p < 0.05-0.01). Although no difference in arterial baroreflex sensitivity was observed, log HF was significantly higher in group A than in group B (p < 0.01), and log L/H was significantly lower in group A than in group B (p < 0.05). The value of log HF correlated inversely with the decrease in HR immediately after both exercise protocols (p < 0.05-0.01). Although log L/H correlated with the decrease in HR after peak exercise (p < 0.05-0.0005), the early decline in HR after constant-load exercise did not correlate with log L/H. Arterial baroreflex sensitivity did not correlate with the decrease in HR at any recovery time. These data suggest that the early phase of HR recovery after light to severe exercise is influenced by the cardiac parasympathetic nervous activity at rest and that the greater central cholinergic modulation of HR in children than in young adults may be responsible in part for children's faster HR recovery after exercise.

Adolescent↗
PubMed2000

Linkage of autosomal recessive hereditary spastic paraplegia with mental impairment and thin corpus callosum to chromosome 15A13-15.

To date, three loci for autosomal recessive hereditary spastic paraplegia (ARHSP) linked to chromosomes 8p12-q13, 16qter, and 15q13-15 have been characterized. We have clinically characterized 13 Japanese ARHSP families and performed genetic linkage analyses. All 13 families were classified as having the "complicated" form, which manifests with mental impairment and thin corpus callosum. Linkage to the 8p12-q13 and 16qter loci was excluded, although 10 of the 13 families showed marker data consistent with linkage to the 15q13-15 locus. The multipoint LOD score of the 10 families linked to chromosome 15 was above 9.00 in the 3-centimorgan segment flanked by D15S994 and D15S659, with a maximum multipoint LOD score of 9.68 at a position 1.2 centimorgans telomeric from D15S994 to D15S659. We have shown that ARHSP with thin corpus callosum, a subtype of recessive spastic paraplegia, maps to chromosome 15q13-15.

Adolescent↗
PubMed2000

Identification of plasma antibody epitopes and gene abnormalities in Japanese hemophilia A patients with factor VIII inhibitor.

Eleven Japanese hemophilia A patients with anti-factor VIII (FVIII) inhibitors were studied to localize both their inhibitory antibody epitopes and their genotypes. The inhibitor epitopes were studied in nine severe hemophilia A patients by means of a scanning method using the oligopeptide panel covering the FVIII polypeptides without the B domain. The 107 15 mer-peptides were synthesized on solid-phase pins and analyzed for their reactivity with diluted patient plasma. As indicated previously, a series of peptides corresponding to the A2 and C2 domains were recognized by plasma antibodies from 2 patients and 4 patients, respectively. In contrast, all the antibodies bound to several epitopes in the A3 domain, while an epitope 1809-1821 covering the putative factor IX binding site was found in 3 patients. Southern blotting analysis showed that 8 out of 11 patients had either gene deletions or inversions of the FVIII gene, indicating a higher proportion of gross gene alterations in inhibitor-positive hemophilia A patients. However, the correlation of gene abnormality type with epitope location was not fully established.

Adult↗
PubMed2000

Homozygous Pro74-->Arg mutation in the platelet glycoprotein Ibbeta gene associated with Bernard-Soulier syndrome.

Bernard-Soulier syndrome (BSS) is an autosomal recessive bleeding disorder due to quantitative or qualitative abnormalities in the glycoprotein (GP) Ib/IX/V complex, the platelet receptor for von Willebrand factor. This complex is composed of four subunits, GPIbalpha, GPIbbeta, GPIX and GPV. We describe here the genetic basis of the disorder in a patient with BSS. Flow cytometric analysis of the patient's platelets showed greatly reduced GPIbalpha and GPIX surface expression. Immunoblot analysis disclosed absence of GPIbalpha, GPIbbeta and GPIX in the platelets. DNA sequencing analysis revealed a novel missense mutation in the GPIbbeta gene that converts Pro (CCG) to Arg (CGG) at residue 74. Homozygosity of the mutation was confirmed by allele-specific restriction analysis, chromosome 22 microsatellite analysis and quantitative Southern blotting. The mutant GPIbbeta was normally transcribed. Transient transfection studies confirmed that mutant GPIbbeta impairs surface expression of GPIb/IX, showing that the mutation is responsible for a BSS phenotype observed in the patient.

Amino Acid Substitution↗
PubMed2000

A novel human multiple myeloma-derived cell line, NCU-MM-1, carrying t(2;11)(q11;q23) and t(8;22)(q24;q11) chromosomal translocations with overexpression of c-Myc protein.

A novel cell line, designated as NCU-MM-1, was established from a 66-year-old female patient with multiple myeloma (MM) that had shown rapid progression from solitary plasmacytoma to plasma cell leukemia. Interestingly, cytogenetic analysis including fluorescence in situ hybridization analysis disclosed that this cell line carried 2 kinds of chromosomal translocations involving immunoglobulin light chain (IgL) gene loci without the presence of 14q32 translocations (14q+). The Ig lambda locus juxtaposed to the c-MYC locus at 8q24 on the derivative (8) chromosome and a concomitant overexpression of the c-Myc protein was observed. On the derivative (11) chromosome, the Ig kappa locus was also fused to the chromosome 11q23 locus, which is known to be a nonrandom translocation breakpoint in mature B-cell malignancies. The NCU-MM-1 cell line may thus be useful not only for the identification of the responsible proto-oncogene(s) mapped to 11q23, deregulated by the Ig kappa enhancer sequences, but also for clarification of the molecular origin of MM lacking 14q+ chromosomes because IgL rearrangements can physiologically begin to occur in the pre-B-cell stage.

Aged↗
PubMed2000

[Induced hypertensive chemotherapy with angiotensin II found effective for mediastinal lymph node metastases of unknown origin].

A 62-year-old woman suffering from gallbladder stone had a remarkably high preoperative CEA level of 525 ng/ml. Computed tomography revealed swollen mediastinal lymph nodes. Lymph node biopsy during thoracotomy led to a diagnosis of metastasis from poorly differentiated adenocarcinoma. Although thorough examinations were performed, the origin of the adenocarcinoma could not be detected. In this case, induced hypertensive chemotherapy with angiotensin II was effective. The mediastinal lymph nodes diminished remarkably and the patient's CEA level decreased to 22 ng/ml. Induced hypertensive chemotherapy with angiotensin II might be a useful treatment for cancer metastases of unknown origin.

Adenocarcinoma↗
PubMed1999

Recognition of target DNA and transcription activation by the CO-sensing transcriptional activator CooA.

CooA from Rhodospirillum rubrum is a heme-based CO-sensing transcriptional activator, in which CO acts as a physiological effector. In this study, we examined the mechanism of site-specific recognition and transcriptional activation by CooA by elucidating the transcriptional activator activity of the mutant CooA proteins and the chimeric proteins derived from CRP and CooA and the promoter activity of the mutant promoters. Site-directed mutagenesis has revealed that Arg(177), Gln(178), and Ser(181) on the recognition helix of the helix-turn-helix motif in CooA are responsible for the site-specific recognition. The side chains of these amino acid residues at positions 177, 178, and 181 are believed to be hydrogen bonding to the G:A, T:A, and C:G pairs at positions 2/15, 3/14, and 4/13 in the CooA-dependent promoters to recognize the DNA site for CooA. The properties of the CRP/CooA chimeric proteins constructed in this work suggest that CooA activates transcription by a similar mechanism to that of CRP at Class II CRP-dependent promoters.

Amino Acid Sequence↗
PubMed1999

Intraluminal increase of superoxide anion following transient focal cerebral ischemia in rats.

Using a modification of Karnovsky's Mn2+/diaminobenzizine (DAB) technique, we examined the production of superoxide anion (.O-2) in the vascular lumen following transient occlusion and reperfusion of the left middle cerebral artery (MCA) in Sprague-Dawley rats. The MCA was occluded for 2 h using an intraluminal suture method. Zero, 15, 30, and 60 min after reperfusion, animals were perfused transcardially with buffer containing Mn2+ and DAB, and brain samples were prepared for light and electron microscopic examination. The amber reaction deposits of.O-2 were observable to the naked eye along the major cerebral vessels of the ischemic hemisphere after each reperfusion period. Upon microscopic examination the deposits were revealed to be within arterial, capillary, and venular lumen. The amount of reaction deposits in the ischemic hemisphere corresponded to the duration of reperfusion. The formation of.O-2 was suppressed when the perfusate contained superoxide dismutase and when either Mn2+ or DAB was omitted, confirming that the reaction products produced are due to the enhanced production of.O-2. These results show that there is a progressive increase in intraluminal. O-2 during reperfusion following an ischemic insult which may participate in the aggravation of cerebral damage.

Animals↗
PubMed1999

An external ion microbeam for studies of biological samples.

A new external ion-beam system was developed and combined with a light ion-microbeam system in JAERI Takasaki. The system is designed for micro-particle-induced X-ray emission analysis of biological samples in air environment with 1 micron spatial resolution. One of the most serious problems in keeping such a high spatial resolution is multiple scattering in a beam exit window. Thin Kapton film (7.5 microns thick) was adopted as the exit window as well as a sample backing foil to minimize the distance between the film and samples. The lifetime of the foil under ion irradiation and spatial resolution of the external microbeam were investigated. The results shows that the film can endure sufficient long-time irradiation to take elemental maps and the resolution can be kept nearly 1 micron.

Biological Assay↗
PubMed1999

Mapping of a gene for May-Hegglin anomaly to chromosome 22q.

May-Hegglin anomaly (MHA) is a rare autosomal dominant platelet disorder characterized by the triad of giant platelets, thrombocytopenia and leukocyte inclusions. Both the molecular and the genetic defects responsible for this disorder remain unknown. In order to map the gene responsible for MHA, we performed a genome-wide linkage study using highly polymorphic short tandem repeat markers in a single Japanese MHA family. Significant linkage was obtained for the markers on the long arm of chromosome 22 (22q12.3-q13.2), with a maximum two-point lod score of 4.52 at a recombination fraction of 0.00 for the markers D22S1142 and D22S277. Haplotype analysis mapped a critical region for the disease locus to a 13.6-centimorgan region, between D22S280 and D22S272. The relative proximity of the platelet GPIbbeta gene (22q11.2) to this region, as well as its involvement in an isolated giant platelet disorder, suggested a possible involvement of GPIbbeta mutations in MHA. However, DNA-sequencing analysis in two patients revealed no abnormality in the sequence of the GPIbbeta gene. This is the first report of linkage for MHA, and further analysis of this locus may lead to the identification of a gene the product of which regulates platelet and leukocyte morphology.

Adult↗
PubMed1999

Comparison of the right and left ventricle as a systemic ventricle during exercise in patients with congenital heart disease.

BACKGROUND: Few studies have investigated the clinical advantages of surgical correction with the morphologic left ventricle (MLV) instead of the morphologic right ventricle as a systemic ventricle (SV) in patients with congenital heart disease. METHODS: Twenty-four healthy control subjects (group A1), 6 patients with isolated congenitally corrected transposition of the great arteries (TGA) (group A2), 16 patients with TGA who had undergone an arterial switch operation (group B1), 18 patients with TGA who had undergone a venous switch operation (group B2), 9 patients with atrioventricular and ventriculoarterial discordance who had undergone a double switch operation (group C1), and 6 patients with atrioventricular and ventriculoarterial discordance who had undergone a conventional external conduit operation from the MLV to the pulmonary artery (group C2), performed treadmill exercise testing. Their heart rate (HR), oxygen uptake (VO2), and oxygen pulse (O2 pulse), which reflects individual stroke volume, were measured, and contractile function was assessed by echocardiography. RESULTS: The peak HR for the patients after a definitive operation were significantly lower than that in group A1 and was correlated with peak VO2 (r =.67, P <.0001). The peak VO2 and peak O2 pulse for the groups A2 and B2 were significantly lower than those for the groups A1 and B1, respectively. The peak O2 pulse data were strongly correlated with those of peak VO 2 (r = 0.91, P <.0001). The left ventricular ejection fraction was significantly lower in groups B1 and C1 than in group A1 and was correlated with peak VO 2 (r =.50, P <.01). No significant differences in VO2, HR, and O 2 pulse at peak exercise were observed between groups C1 and C2. CONCLUSIONS: Chronotropic incompetence and an impaired response of the stroke volume of the MRV during exercise are partly responsible for the reduced exercise capacity in groups A2 and B2 compared with groups with the MLV as an SV, and the SV function at rest is also related to exercise capacity. Superiority of the double-switch operation compared with the conventional conduit operation was not observed. A longer-term follow-up is necessary before the advantages of these 2 operations can be compared.

Adolescent↗
PubMed1999

Dichotic listening in patients with situs inversus: brain asymmetry and situs asymmetry.

In order to investigate the relation between situs asymmetry and functional asymmetry of the human brain, a consonant-vowel syllable dichotic listening test known as the Standard Dichotic Listening Test (SDLT) was administered to nine subjects with situs inversus (SI) that ranged in age from 6 to 46 years old (mean of 21.8 years old, S.D. = 15.6); the four males and five females all exhibited strong right-handedness. The SDLT was also used to study twenty four age-matched normal subjects that were from 6 to 48 years old (mean 21.7 years old, S.D. = 15.3); the twelve males and twelve females were all strongly right-handed and served as a control group. Eight out of the nine subjects (88.9%) with SI more often reproduced the sounds from the right ear than sounds from the left ear; this is called right ear advantage (REA). The ratio of REA in the control group was almost the same, i.e., nineteen out of the twenty-four subjects (79.1%) showed REA. Results of the present study suggest that the left-right reversal in situs inversus does not involve functional asymmetry of the brain. As such, the system that produces functional asymmetry in the human brain must independently recognize laterality from situs asymmetry.

Adolescent↗
PubMed1999

The relationship between auditory ERP and neuropsychological assessments in schizophrenia.

To clarify the cognitive significance of event-related potential (ERP) abnormalities in schizophrenia, we examined the relationships of amplitudes and latencies of ERP components with performance on neuropsychological tests in schizophrenic patients. Twenty patients underwent the Trail Making B Test (TM-B), which is sensitive to frontal lobe dysfunction, and the logical memory, verbal paired-association, and visual reproduction subtests of the Wechsler Memory Scale (WMS), which are sensitive to temporal lobe dysfunctions, and ERP recordings during performance of an oddball auditory discrimination task. Pearson product-moment correlations indicated that an increased P200 amplitude was correlated with poor performance on the TM-B, whereas a decreased P300 amplitude was correlated with poor performance on the verbal paired-association subtest of the WMS. These findings suggest that a P200 abnormality represents the frontal lobe dysfunction, and a P300 abnormality represents the left temporal lobe dysfunction in schizophrenia.

Adolescent↗
PubMed1999

Clinical features of isolated noncompaction of the ventricular myocardium: long-term clinical course, hemodynamic properties, and genetic background.

OBJECTIVES: A nationwide survey was conducted to clarify the clinical features of isolated noncompaction of the ventricular myocardium (INVM) in Japanese children in comparison with features previously described in patients with INVM. BACKGROUND: Isolated noncompaction of the ventricular myocardium is a rare disorder characterized by an excessively prominent trabecular meshwork. It is accompanied by depressed ventricular function, systemic embolism and ventricular arrhythmia. METHODS: A questionnaire specifically designed for this study was sent to 150 hospitals in Japan where a pediatric cardiology division exists. RESULTS: Twenty-seven patients were diagnosed by two-dimensional echocardiography, their ages ranging from one week to 15 years at presentation, with follow-up lasting as long as 17 years. The gross anatomical appearance and the extension of noncompacted myocardium predominantly at the apex observed on two-dimensional echocardiograms were similar to observations reported previously. Dissimilarities included a greater number of asymptomatic patients at initial presentation, a longer clinical course with gradually depressed left ventricular function, no systemic embolism, and rare ventricular tachycardia in the Japanese children. Cardiac catheterization disclosed normal left ventricular end-diastolic volume and increased left ventricular end-diastolic pressure in most cases, consistent with restrictive hemodynamics. A higher incidence of Wolff-Parkinson-White syndrome was found in the children, whereas left bundle branch block was rarer than reported in adults. Familial recurrence was high (44%) and included many women. CONCLUSIONS: In Japanese children, INVM can be found by screening examinations at asymptomatic stage, and it might have a longer dinical course with gradually depressed left ventricular function and restrictive hemodynamics. The pattern of familial recurrence we observed implies that INVM is a distinctive clinical entity with a heterogeneous genetic background.

Adolescent↗
PubMed1999

Histocompatibility antigens and alleles in Japanese haemophilia A patients with or without factor VIII antibodies.

We carried out human leukocyte antigen (HLA)-A, B, Cw, DR and DQ serological typing and HLA-DQA1, DQB1, DRB1 and DPB1 genetic typing for 46 Japanese haemophilia A patients, including 20 who had developed an antibody to factor VIII. It appears that anti FVIII inhibitor formation is associated with the major histocompatibility complex in Japanese haemophilia A patients. Absence of HLA-A24 is a principal risk factor for inhibitor formation in Japanese haemophilia A patients. As supplemental risk factors, HLA-DR4.1, DQ4 and DQA1*0301=2 are positively associated with patients exhibiting inhibitor compared with normal subjects. This and previous studies show that the association between HLA antigens and the formation of inhibitor depends on race. Data of HLA typing may be useful for the recognition of groups at high risk for the possible formation of inhibitor among Japanese haemophilia A patients.

Alleles↗