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F Yamamoto

Publications and source records attributed to F Yamamoto.

At least 19 recordsLinked to original sources
PubMed2004

A DNA microarray-based methylation-sensitive (MS)-AFLP hybridization method for genetic and epigenetic analyses.

We previously developed a PCR-based DNA fingerprinting technique named the Methylation Sensitive (MS)-AFLP method, which permits comparative genome-wide scanning of methylation status with a manageable number of fingerprinting experiments. The technique uses the methylation sensitive restriction enzyme NotI in the context of the existing Amplified Fragment Length Polymorphism (AFLP) method. Here we report the successful conversion of this gel electrophoresis-based DNA fingerprinting technique into a DNA microarray hybridization technique (DNA Microarray MS-AFLP). By performing a total of 30 (15 x 2 reciprocal labeling) DNA Microarray MS-AFLP hybridization experiments on genomic DNA from two breast and three prostate cancer cell lines in all pairwise combinations, and Southern hybridization experiments using more than 100 different probes, we have demonstrated that the DNA Microarray MS-AFLP is a reliable method for genetic and epigenetic analyses. No statistically significant differences were observed in the number of differences between the breast-prostate hybridization experiments and the breast-breast or prostate-prostate comparisons.

Blotting, Southern↗
PubMed2004

Concentration of clarithromycin and 14-R-hydroxy-clarithromycin in plasma of patients with Mycobacterium avium complex infection, before and after the addition of rifampicin.

Clarithromycin (CAM) and rifampicin (RFP) have both been recognized to be effective antibiotic agents against Mycobacterium avium complex (MAC) infection. Rifamycin derivatives including RFP and rifabutin modulate the CAM metabolism by inducing the hepatic cytochrome p-450 3A4. To clarify the effect of RFP on the CAM metabolism, we measured the plasma concentration of CAM and 14-R-hydroxyclarithromycin (M-5), the major metabolite of CAM, in 9 patients suffering from MAC infection before and after the addition of RFP. After the addition of RFP, the mean plasma concentration of CAM significantly decreased, while that of M-5 did not. In addition, the amount of CAM + M-5 concentration also significantly decreased. As M-5 is less effective against MAC infection than CAM, more attention should thus be paid to the plasma CAM concentration in patients administered CAM and RFP concomitantly.

Aged↗
PubMed2003

Tei index determined by tissue Doppler imaging in patients with pulmonary regurgitation after repair of tetralogy of Fallot.

The myocardial performance index (Tei index) determined by the pulsed Doppler method is a simple and noninvasive measurement for assessing global right ventricular (RV) function. This index can also be obtained by tissue Doppler imaging (TDI). The effects of significant pulmonary regurgitation (PR) on the determination of the Tei index by these two methods have not been investigated. We examined 15 patients (6.3 +/- 2.2 years) with significant PR after repair of tetralogy of Fallot (TOF) and 24 age-matched healthy children. Myocardial wall motion velocities at the tricuspid annulus were assessed during systole (Sa), early diastole (Ea), and late diastole (Aa) from a four-chamber view. Pulsed Doppler-Tei index and TDI-Tei index were measured as reported previously. The Tei index obtained by the pulsed Doppler method in TOF patients did not differ from that in normal children (0.30 +/- 0. 12 vs 0.32 +/- 0.07, p = not significant). TDI showed that TOF patients had significantly decreased Ea, Aa, and Sa velocities compared to those of normal children. Both isovolumic contraction time and isovolumic relaxation time in TOF patients were significantly longer than those in normal children (88 +/- 18 vs 62 +/- 23 msec and 46 +/- 11 vs 21 +/- 12 msec, respectively; p < 0.0001), although the duration of Sa did not differ between the two groups. Consequently, the Tei index as measured by TDI was significantly greater in TOF patients than in normal children (0.48 +/- 0.07 vs 0.30 +/- 0.07, p < 0.0001). The Tei index measured by the pulsed Doppler method is limited in its ability to assess RV function in patients with significant PR. However, the Tei index determined by TDI is a sensitive indicator of RV function in these patients, and it appears to be a promising new means of assessing global RV function in patients with significant PR.

Blood Flow Velocity↗
PubMed2003

Anaesthesia for awake craniotomy with non-invasive positive pressure ventilation.

Airway management during awake craniotomy is a crucial part of the anaesthetic technique, but it remains the subject of debate. We report two cases of anaesthesia for awake craniotomy using non-invasive positive pressure ventilation; biphasic positive airway pressure or proportional assist ventilation was employed. Both ventilatory techniques provided adequate lung ventilation, smooth transition between anaesthesia and arousal, and patient comfort.

Adult↗
PubMed2003

A base substitution in the interleukin-10 (IL-10) promoter between Sp1 and ets-1 binding sites is not associated with variation of IL-10 levels.

Interleukin 10 (IL-10) may play an important anti-inflammatory and immunoregulatory role in asthma. In this study, we investigated the role of a C to A substitution at position -627 of the IL-10 promoter, located in a necessary transcriptional region, which contains a number of putative transcriptional binding sites. The -627 nucleotide position is itself flanked by Sp-1 and ets-1 binding sites. We studied the allele frequency in 53 unrelated subjects from an admixed Caucasian, Asian and Pacific Islander group with personal or family histories of asthma. The frequency of homozygous C/C, heterozygous C/A, and homozygous A/A alleles at position -627 was 0.28, 0.44 and 0.28, respectively. In vitro assays indicated no differences between the C/C and A/A forms in binding transcriptional factors, especially Sp-1 factor, or in promoter activity. Moreover, in this selected population, there was no association between the C to A substitution and serum IL-10 levels. The mean level of IL-10 serum was determined to be 3.87 +/- 1.23 pg/ml in subjects carrying the A/A genotype, 3.47 +/- 0.57 for C/C genotype and 3.13 +/- 0.41 for the heterozygous (C/A genotype). This requires confirmation by comparing to non-asthmatic subjects. We conclude that although the -627 A allele occurs frequently (50% of alleles) in this selected group, in vitro assays and serum IL-10 levels suggest that the -627C-->A substitution represents a silent or neutral variant in the IL-10 promoter.

Alleles↗
PubMed2003

Polymorphisms in the interleukin-4 receptor alpha chain: association with traits of allergy and asthma in an admixed population in Hawaii.

Single nucleotide polymorphisms (SNPs) in the gene encoding the interleukin-4 receptor alpha chain (IL-4R alpha) have been associated with IgE levels or clinical atopy in some populations. Two SNPs that encode S503P and Q576R in the intracytoplasmic domain of the receptor are associated with loss or gain of function, respectively. We investigated the frequency of these SNPs and their association with traits of allergic asthma in 36 unrelated subjects selected from a racially admixed, clinically ascertained study population with family histories of asthma. The frequency of the 1682 T to C substitution that encodes S503P was 0.11 (70 alleles analyzed, from 29 TT homozygotes and 6 TC heterozygotes). The frequency of the 1902 A to G substitution that encodes Q576R was 0.26 (68 alleles analyzed, from 20 AA homozygotes, 10 AG heterozygotes and 4 GG homozygotes). In this atopic admixed sample, no significant association was detected between the variant genotypes and serum IgE levels, percentage of eosinophils, skin test reactivity, diagnosis of asthma or methacholine reactivity. More conclusive findings await clinical characterization of non-atopic, non-asthmatic subjects as well as more efficient and extensive haplotyping.

Asthma↗
PubMed2001

Molecular genetic basis of porcine histo-blood group AO system.

Histo-blood group A and B antigens are oligosaccharide antigens important in transfusion and transplantation medicine. The final steps in the synthesis of these antigens are catalyzed by glycosyltransferases encoded by the functional alleles at the ABO locus. Humans have 3 major alleles (A, B, and O), whereas pigs are known to have only A and O alleles. This paper reports the molecular genetic basis of the porcine AO system. The porcine A gene is homologous to the ABO genes in humans and other species. It encodes an alpha1 --> 3 N-acetyl-D-galactosaminyltransferase that synthesizes A antigens. Southern hybridization experiments using a porcine A gene coding-sequence probe failed to identify a corresponding homologous sequence in genomic DNA from group O pigs, thus suggesting a major deletion in the O gene. Therefore, inadvertent activation of a silent O gene seems unlikely in porcine organs xenotransplanted into humans.

ABO Blood-Group System↗
PubMed2001

4,5,9,10-Tetrahydro-1,4-ethanobenz[b]quinolizine as a prodrug for its quinolizinium cation as a ligand to the open state of the TCP-binding site of NMDA receptors.

A new derivative of 4,5,9,10-tetrahydro-1,4-ethanobenz[b]quinolizine (2) has been designed as a prodrug for its quinolizinium cation (1) that is a potent antagonist of the TCP-binding site of NMDA receptors at the open state. The 11C-labeled 2 showed high accumulation of radioactivity in the brain in an in vivo biodistribution study. The speculation of 2 as a prodrug of 1 has been proven by the fact that 1 was observed in a high ratio to 2 in an analysis by RP-HPLC of the brain homogenates.

Animals↗
PubMed2001

Murine equivalent of the human histo-blood group ABO gene is a cis-AB gene and encodes a glycosyltransferase with both A and B transferase activity.

We have cloned murine genomic and complementary DNA that is equivalent to the human ABO gene. The murine gene consists of at least six coding exons and spans at least 11 kilobase pairs. Exon-intron boundaries are similar to those of the human gene. Unlike human A and B genes that encode two distinct glycosyltransferases with different donor nucleotide-sugar specificities, the murine gene is a cis-AB gene that encodes an enzyme with both A and B transferase activities, and this cis-AB gene prevails in the mouse population. Cloning of the murine AB gene may be helpful in establishing a mouse model system to assess the functionality of the ABO genes in the future.

ABO Blood-Group System↗
PubMed2001

Notl-Msell methylation-sensitive amplied fragment length polymorhism for DNA methylation analysis of human cancers.

We have applied a methylation-sensitive restriction endonuclease, NotI, to the existing amplified fragment length polymorphism (AFLP) method and developed NotI-MseI methylation-sensitive-AFLP (MS-AFLP). NotI-MseI MS-AFLP allows the analysis of DNA methylation alterations at the NotI sites scattered over the genome. Hypermethylation and hypomethylation are visualized by the decrease and increase in the band intensity of DNA fingerprints. Identification of consistent changes can be facilitated through parallel electrophoresis of multiple samples. DNA fragments exhibiting alterations can be cloned from fingerprint bands by amplification of gel-eluted DNA with the same pair of primers used for radioactive fingerprint presentation. Fluorescent NotI-MseI MS-AFLP offers a safer method of studying the alterations in DNA methylation, and may be applied to the hybridization of DNA microarrays in the future. Using NotI-MseI MS-AFLP, we observed frequent hypomethylation of a satellite DNA repeat sequence in a majority of breast tumors.

Blotting, Southern↗
PubMed2001

Intracranial vertebral artery dissection presenting as subarachnoid hemorrhage: successful endovascular treatment.

INTRODUCTION: Intracranial vertebral artery dissection is a rare condition which may present as subarachnoid hemorrhage. In this situation, treatment is controversial. CASE REPORT: A case of intracranial right vertebral artery dissection in a 55-year-old woman presenting with subarachnoid hemorrhage is reported. The patient underwent therapeutic occlusion of the dissected artery through microcatheterization using pushing detachable platinum microcoils and had a good outcome. At this moment, the patient has a normal neurologic examination and a control digital subtraction angiography 1 year after the procedure showed an occluded right vertebral artery at V3; there was retrograde flow in the right intracranial vertebral artery up to the origin of a meningeal branch; the artery was thin and had mural irregularities, without any evidence of aneurismatic dilatation. DISCUSSION: We review the literature and discuss the role of endovascular therapy and other therapeutic options in the treatment of this condition.

Aortic Dissection↗
PubMed2001

The effect of epidural anesthesia on respiratory distress induced by airway occlusion in isoflurane-anesthetized cats.

UNLABELLED: The role of afferent information from the chest wall in the genesis of dyspnea is not fully elucidated. We have developed an animal model for the study of airway occlusion (AO) and proposed new concepts of minimum alveolar anesthetic concentration for AO (MACAOR) and the duration from the start of AO to the onset of the positive motor response (DOCCL) to evaluate respiratory distress quantitatively. We examined the effects of thoracic epidural anesthesia on respiratory distress by using our animal model. Adult cats (n = 24) were anesthetized with isoflurane, and an epidural catheter was placed after T9 laminectomy. After determination of MACAOR, DOCCL was measured. Animals were then randomly assigned into three groups: the EPD Group (n = 12) received epidural 1% lidocaine (0.4 mL/kg), IM saline (0.4 mL/kg), and saline infusion. The IM Group (n = 6) received epidural saline (0.4 mL/kg), IM 1% lidocaine (1 mL/kg), and saline infusion. The PHE Group (n = 6) received epidural 1% lidocaine (0.4 mL/kg) and IV phenylephrine (0.5-1 microg. kg(-1). min(-1)) to maintain a stable arterial blood pressure. DOCCL and MACAOR were measured in each animal at 15 min after the administration of drugs. Plasma lidocaine concentrations were measured before and after epidural or IM injection. DOCCL was significantly longer after epidural injection in all groups than before the injection. Although there was no significant difference in the values of MACAOR between before and after the epidural injection in the EPD Group, the IM administration of lidocaine in the IM Group significantly reduced MACAOR. Plasma concentrations of lidocaine were similar in all groups at all measurement points. Our data indicate that thoracic epidural anesthesia using 1% lidocaine significantly reduced respiratory distress induced by AO. This effect is most likely caused by a systemic effect of lidocaine rather than by reduced afferent information from the chest wall. IMPLICATIONS: Thoracic epidural anesthesia reduced respiratory distress induced by airway occlusion. This effect is most likely caused by the systemic effect of lidocaine, rather than by the reduced afferent information from the chest wall.

Anesthesia, Epidural↗
PubMed2001

Reduced tolerance of global ischemia in the hypertrophied heart. Effect of coronary flow regulation during reperfusion on postischemic recovery.

OBJECTIVE: Reduced coronary reserve during reperfusion may cause postischemic diastolic dysfunction in pressure-overload-induced hypertrophy. We studied the effect of coronary flow regulation (simulated hyperemic or depressed flow) on postischemic cardiac function during reperfusion. METHODS: Left ventricular pressure overload was induced in 4-week-old rats by abdominal aortic constriction. At 6 weeks of age, isolated Langendorff-perfused hearts (perfusion pressures: 75 mmHg in controls and 110 mmHg in the aortic constriction group) were subjected to hypothermic global ischemia (15 degrees C, 210 min), followed by 2 types of coronary flow regulation during the initial 20 min of reperfusion--manipulated high flow in control hearts (group I), manipulated low flow in control hearts (group II), manipulated high flow in aortic constriction hearts (group III), and manipulated low flow in aortic constriction hearts (group IV) (n = 6/group), and then constant pressure perfusion during the subsequent 45 min of reperfusion. Cardiac function was measured using an isovolumic balloon in the pre- and postischemic periods. RESULTS: Aortic constriction hearts exhibited greater left ventricular end-diastolic pressure than did control hearts. The increase in left ventricular end-diastolic pressure did not differ between group I (3 +/- 2 mmHg) and group II (-1 +/- 1 mmHg) or between group III (29 +/- 5 mmHg) and group IV (30 +/- 6 mmHg). No difference was seen in postischemic recovery of left ventricular systolic pressure between high and low flow groups in control and aortic constriction hearts. CONCLUSION: Manipulations in coronary flow during reperfusion did not affect postischemic cardiac function in control or aortic constriction hearts, suggesting that depressed coronary flow during early reperfusion is not a primary cause of postischemic diastolic dysfunction in the hypertrophied myocardium.

Animals↗
PubMed2000

Mode of onset of ventricular fibrillation in patients with Brugada syndrome detected by implantable cardioverter defibrillator therapy.

OBJECTIVES: We sought to demonstrate the mode of spontaneous onset of ventricular fibrillation (VF) in patients with Brugada syndrome. BACKGROUND: The electrophysiologic mechanisms of VF in Brugada syndrome have not been fully investigated. METHODS: Nineteen patients (all male, mean age 47 +/- 12 years) with Brugada syndrome were treated with an implantable cardioverter defibrillator (ICD). The implanted devices were capable of storing electrograms during an arrhythmic event. We investigated the mode of spontaneous onset of VF according to the electrocardiographic features during the episode of VF, which were obtained from stored electrograms of ICDs and/or electrocardiographic (ECG) monitoring. RESULTS: During a follow-up of 34.7 +/- 19.4 months (range 14 to 81 months), 46 episodes of spontaneous VF attacks were documented in 7/19 (37%) patients. The event-free period between ICD implantation and the first spontaneous occurrence of VF was 14.6 +/- 12.1 months (range 3.7 to 27.4 months). We investigated 33/46 episodes of VF, for which electrocardiographic features (10 to 20 s before and during VF) were obtained from ICDs and/or ECG monitoring in five patients. A total of 22/33 episodes of VF were preceded by premature ventricular contractions (PVCs), which were almost identical to the initiating PVCs of VF. Furthermore, in three patients who had multiple VF episodes, VF attacks were always initiated by the same respective PVC. The coupling interval of the initiating PVCs of VF was 388 +/- 28 ms. CONCLUSIONS: Spontaneous episodes of VF in patients with Brugada syndrome were triggered by specific PVCs. These findings may provide important insights into the pathophysiological mechanisms causing VF in Brugada syndrome.

Bundle-Branch Block↗
PubMed2000

Different mechanisms between premitotic apoptosis and postmitotic apoptosis in X-irradiated U937 cells.

PURPOSE: Apoptosis is currently being evaluated for its importance as a pathway of radiation-induced cell death. However, the difference in the mechanisms between premitotic and postmitotic apoptosis following X-irradiation remains not well understood. We show here that the human monoblastoid cell line U937 can be induced to undergo these two different types of apoptosis. METHODS AND MATERIALS: U937 cells were irradiated at a dose of 5 or 20 Gy, and the DNA fragmentation rate was measured by both flow cytometric analysis and gel electrophoresis. Activation of caspase-3 was detected by Western blot analysis and fluorogenic assay using acetyl-Asp-Glu-Val-Asp-7-amino-4-methyl-coumarin (Ac-DEVD-AMC). Detection of mitochondrial transmembrane potential (DeltaPsi) was performed by using Rho123. Chasing of S-phase fraction following X-irradiation was performed after labeling with 5-bromo-2'-deoxyuridine (BrdU). Thymidine was used for synchronization of the cells. Inhibition of caspase-3 activity was achieved by Acetyl-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO). RESULTS: Time courses of the apoptotic rates, caspase activation, and DeltaPsi indicated that two different types of cell death were induced by the different X-ray doses. High-dose X-ray (20 Gy) induced a rapid and strong apoptosis, whereas low-dose X-ray (5 Gy) induced a slow and mild apoptosis. Cell-cycle analyses revealed that there was cell death before cell division in the former apoptosis but the cells must be dying after cell division in the latter apoptosis. By means of cell-cycle synchronization, the S-phase cells proved to be the most sensitive fraction to premitotic apoptosis, but an obvious difference in the susceptibility to cell death among the cell-cycle phases was not observed in postmitotic apoptosis. Ac-DEVD-CHO treatment effectively blocked caspase activity and premitotic apoptosis, but it failed to block postmitotic apoptosis. CONCLUSIONS: Irradiation of U937 cells at different X-ray doses induced two different types of apoptotic cell death, premitotic apoptosis and postmitotic apoptosis, which are characterized by the time course and cell-cycle specificity. Decision concerning these two types of apoptotic cell death may be made by the difference in the magnitude of cell damage following X-irradiation.

Apoptosis↗
PubMed2000

Evaluation of leukocyte-reducing arterial line filter (LG6) for postoperative lung function, using cardiopulmonary bypass.

OBJECTIVE: To prevent postoperative pulmonary dysfunction, we have investigated the effect of the Leuko-Guard 6 leukocyte-reducing arterial line filter (LG6) on postoperative lung function. METHODS: Twenty-six cases of adult valvular heart disease were included in this study. Thirteen cases were operated upon using the LG6 (Group LG), and 13 cases were operated upon using a conventional arterial line filter (Group C). Neutrophil, polymorphonuclear leukocyte elastase and lipoperoxide were measured for this study, and the lung function was evaluated using the Oxygenation Index (PaO2/FiO2). RESULTS: Statistically significant differences were observed in neutrophil counts between Group LG and Group C (LG = 2225 +/- 572/mm3, C = 3157 +/- 1413/mm3, p = 0.04) at 5 minutes after the onset of cardiopulmonary bypass. In simultaneous blood sampling from the pulmonary artery and the pulmonary vein, the sequestration of neutrophil in the lung decreased in Group LG after the discontinuation of cardiopulmonary bypass. Release of polymorphonuclear leukocyte elastase from the lungs was significantly decreased (p = 0.04) in the Group LG at 1 hour post-bypass. Significant differences were observed in the Oxygenation Index between Group LG and Group C (LG = 398 +/- 72, C = 326 +/- 71, p = 0.019) at 3 hours post-bypass. CONCLUSION: We concluded that LG6 improved the postoperative lung function, and its mechanism might be derived from the prevention of leukosequestration in the lungs that occurs during the rewarming phase due to selective absorption of activated leukocyte by the LG6.

Adsorption↗