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Biomedical subjects

A Taguchi

Publications and source records attributed to A Taguchi.

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

Body surface distribution and response to drugs of ST segment elevation in Brugada syndrome: clinical implication of eighty-seven-lead body surface potential mapping and its application to twelve-lead electrocardiograms.

INTRODUCTION: Body surface distribution and magnitude of ST segment elevation and their reflection in 12-lead ECGs have not been clarified in Brugada syndrome. METHODS AND RESULTS: Eighty-seven-lead body surface potential mapping and 12-lead ECGs were recorded simultaneously in 25 patients with Brugada syndrome and 40 control patients. The amplitude of the ST segment 20 msec after the end of QRS (ST20) was measured from all 87 leads, and an ST isopotential map was constructed. The maximum ST elevation (maxST20) was distributed in an area of the right ventricular outflow tract in all Brugada patients, and it was larger than that in control patients (0.37 +/- 0.13 vs 0.12 +/- 0.04 mV; P < 0.0005). The maximum was observed on the level of the parasternal fourth intercostal space, on which the V1 and V2 leads of the standard 12-lead ECG were located, in 18 of the 25 Brugada patients in whom typical coved- or saddleback-type ST elevation was seen in leads V1 and V2. The maximum was located on the second intercostal space in the remaining seven Brugada patients in whom only a mild saddleback-type ST elevation was seen in leads V1 and V2 of the 12-lead ECG. Typical ST segment elevation was recognized in leads V1 and V2, which were recorded on the second or third intercostal space. ST elevation in Brugada patients was dramatically normalized by isoproterenol, a beta-adrenergic agonist (maxST20 = 0.17 +/- 0.08 mV; P < 0.0005 vs control conditions), and accentuated by disopyramide, an Na+ channel blocker (maxST20 = 0.50 +/- 0.15 mV; P < 0.0005 vs control conditions), without any change in the location of the maxST20. CONCLUSION: Our data indicate that recordings of leads V1-V3 of the 12-lead ECG on the parasternal second or third intercostal space would be helpful in diagnosing suspected patients with Brugada syndrome. The data suggest that Na+ channel blockers are capable of accentuating ST elevation in leads V1-V3.

Action Potentials↗
PubMed2000

Intracoronary positive and negative contrast jets at a 'napkin ring' coronary stenosis: a case report.

A very short coronary stenosis is somewhat difficult to correctly evaluate by conventional coronary angiography. The demonstration of positive and negative contrast jets observed just distal to the lesion is helpful in identifying the severity of the disease causing this disorder. In the present case, intravascular ultrasound confirmed the presence of a very short stenosis and membranous disease at the site of the lesion. The presence of intracoronary contrast jets reflects the morphology and severity of disease of the membranous type, although the reason for the appearance of contrast jets with this type of lesion should be sought.

Contrast Media↗
PubMed1999

N(epsilon)-(carboxymethyl)lysine adducts of proteins are ligands for receptor for advanced glycation end products that activate cell signaling pathways and modulate gene expression.

Recent studies suggested that interruption of the interaction of advanced glycation end products (AGEs), with the signal-transducing receptor receptor for AGE (RAGE), by administration of the soluble, extracellular ligand-binding domain of RAGE, reversed vascular hyperpermeability and suppressed accelerated atherosclerosis in diabetic rodents. Since the precise molecular target of soluble RAGE in those settings was not elucidated, we tested the hypothesis that predominant specific AGEs within the tissues in disorders such as diabetes and renal failure, N(epsilon)-(carboxymethyl)lysine (CML) adducts, are ligands of RAGE. We demonstrate here that physiologically relevant CML modifications of proteins engage cellular RAGE, thereby activating key cell signaling pathways such as NF-kappaB and modulating gene expression. Thus, CML-RAGE interaction triggers processes intimately linked to accelerated vascular and inflammatory complications that typify disorders in which inflammation is an established component.

Animals↗
PubMed1999

Cloning, sequencing, and characterization of ribosomal protein and RNA polymerase genes from the region analogous to the alpha-operon of escherichia coli in halophilic archaea, halobacterium halobium.

A determination was made of the nucleotide sequence of the 3215-bp region of a ribosomal protein gene cluster (HS13, HS4, HS11, and HeL18), RNA polymerase (RNA poly D), and tRNA genes (tRNAser and tRNAarg) of halophilic Archaea Halobacterium halobium, which is analogous to the alpha-operon of Escherichia coli (tRNAser-HS13-HS4-HS11-RNA poly D-tRNAarg-HeL18). The seven-gene string was preceded by a pseudoknot-like structure similar to the proposed S4 ribosomal protein binding site of the alpha-operon mRNA leader in E. coli. Using an inducible expression system H. halobium HS4 was produced in large amounts in E. coli, and immunoblot analysis showed the S4 to constitute a 21-kDa polypeptide component of the ribosome. Analysis of the deduced amino acids sequence revealed that the HS13, HS4, and HS11 sequences including the RNA polymerase subunit are more similar to their eukaryotic than to their bacterial counterparts. HeL18, located downstream of the gene cluster analogous to the E. coli alpha-operon (S13-S11-S4-RNA poly D-L17), was similar to both the eukaryotic (eL18) and eubacterial ribosomal protein L15 located in the spc-operon, but not to L17 positioned as the terminal gene of the bacterial alpha-operon.

Amino Acid Sequence↗
PubMed1999

RAGE mediates a novel proinflammatory axis: a central cell surface receptor for S100/calgranulin polypeptides.

S100/calgranulin polypeptides are present at sites of inflammation, likely released by inflammatory cells targeted to such loci by a range of environmental cues. We report here that receptor for AGE (RAGE) is a central cell surface receptor for EN-RAGE (extracellular newly identified RAGE-binding protein) and related members of the S100/calgranulin superfamily. Interaction of EN-RAGEs with cellular RAGE on endothelium, mononuclear phagocytes, and lymphocytes triggers cellular activation, with generation of key proinflammatory mediators. Blockade of EN-RAGE/RAGE quenches delayed-type hypersensitivity and inflammatory colitis in murine models by arresting activation of central signaling pathways and expression of inflammatory gene mediators. These data highlight a novel paradigm in inflammation and identify roles for EN-RAGEs and RAGE in chronic cellular activation and tissue injury.

Amino Acid Sequence↗
PubMed1999

Ectopic expression of constitutively activated Ral GTPase inhibits cell shape changes during Drosophila eye development.

The small GTP-binding protein Ral is activated by RalGDS, one of the effector molecules for Ras. Active Ral binds to a GTPase activating protein for CDC42 and Rac. Although previous studies suggest a role for Ral in the regulation of CDC42 and Rac, which are involved in arranging the cytoskeleton, its in vivo function is largely unknown. To examine the effect of overexpressing Ral on development, transgenic Drosophila were generated that overexpress wild-type or mutated Ral during eye development. While wild-type Ral caused no developmental defects, expression of a constitutively activated protein resulted in a rough eye phenotype. Activated Ral did not affect cell fate determination in the larval eye discs but caused severe disruption of the ommatidial organization later in pupal development. Phalloidin staining showed that activated Ral perturbed the cytoskeletal structure and cell shape changes during pupal development. This phenotype is similar to that caused by RhoA overexpression. In addition, the phenotype was synergistically enhanced by the coexpression of RhoA. These results suggest that Ral functions to control the cytoskeletal structure required for cell shape changes during Drosophila development.

Animals↗
PubMed1999

Crystal structure of the E166A mutant of extended-spectrum beta-lactamase Toho-1 at 1.8 A resolution.

Bacterial resistance to beta-lactams is mainly due to the production of beta-lactamase. Especially through the production of extended-spectrum beta-lactamases (ESBLs), bacteria have acquired resistance not only to penicillins, but also to expanded-spectrum cephems. Here, we describe the crystal structure of the E166A mutant of class A beta-lactamase Toho-1 at 1.8 A resolution, the first reported tertiary structure of an ESBL. Instead of the wild-type enzyme, a mutant Toho-1, in which Glu166 was replaced with alanine, was used for this study, because of the strong tendency of the wild-type enzyme to form twinned crystals. The overall structure of Toho-1 is similar to the crystal structures of non-ESBLs, with no pronounced backbone rearrangement of the framework. However, there are some notable local changes. First, a difference in the disposition of an arginine residue, which is at position 244 in non-ESBLs but at position 276 in Toho-1 and other ESBLs, was revealed and the role of this arginine residue is discussed. Moreover, changes in the hydrogen-bonding pattern and in the formation of the hydrophobic core were also observed near the Omega loop. In particular, the lack of hydrogen bonds in the vicinity of the Omega loop could be a cause of the extended substrate specificity of Toho-1. Through the generation of a model for the enzyme-substrate complex, a conformational change of Toho-1 occurring on complex formation is discussed based on the active-site cleft structure and the substrate profile.

Amino Acid Sequence↗
PubMed1999

Relationship between bone mineral density and tooth loss in elderly Japanese women.

OBJECTIVE: To evaluate the relationship between vertebral bone mass and tooth loss and jaw bone mass in elderly Japanese women. METHODS: Mandibular cortical bone mass, alveolar bone height and number of teeth present (total, anterior, and posterior) were compared with the 3rd lumbar vertebral bone mineral density (L3BMD), measured by dual energy computed tomography (DEQCT), in 90 Japanese women by means of multiple regression analysis, controlling for body mass index, menopausal status, years since menopause and self-reported periodontal condition. RESULTS: Mandibular cortical bone mass and number of posterior teeth were associated with both alveolar bone height and L3BMD, but there was no association between alveolar bone height, number of anterior teeth present and L3BMD. CONCLUSION: Our results suggest that the loss of posterior teeth may be associated with a decrease not only in alveolar bone height, but also alveolar bone mineral density (BMD). The latter may be related to a decrease of lumbar vertebral BMD.

Adult↗
PubMed1999

Molecular cloning of a novel member of the HSP110 family of genes, ischemia-responsive protein 94 kDa (irp94), expressed in rat brain after transient forebrain ischemia.

To identify genes induced by transient forebrain ischemia, we used the mRNA differential display technique in the four-vessel occlusion model in rats. Some genes were identified as candidates that encode ischemia-responsive protein, and one of them was cloned as ischemia-responsive protein 94 kDa (irp94) from the rat hippocampal cDNA library. Sequence analysis suggested that rat irp94 was a transcriptional variant or a homologue of mouse apg-2 and human heat shock protein (hsp) 70RY and a member of the HSP110 family, because IRP94 was >90% identical to APG-2 and HSP70RY and approximately 60% identical to the other members of the HSP110 family. Although irp94 mRNA was constitutively expressed in the normal hippocampus, it was clearly enhanced 4-24 h after ischemia for 10 (1.9-fold increase) and 15 min (3.4-fold increase). These changes mainly occurred in neuronal cells, as judged by the localization of irp94 mRNA using in situ hybridization histochemistry. On the other hand, hyperthermic stress did not enhance irp94 mRNA expression, suggesting that irp94 expression was enhanced under ischemic stress and not related to the heat shock signaling mechanism. Our study suggested that irp94, a novel member of the HSP110 family, might play an important role in the environment altering neuronal functions, especially after transient forebrain ischemia.

Animals↗
PubMed1999

The circadian pattern of the development of ventricular fibrillation in patients with Brugada syndrome.

AIMS: Brugada syndrome is considered to be a distinctive subgroup of idiopathic ventricular fibrillation. Identification of the circadian pattern of ventricular fibrillation would contribute to the elucidation of its underlying pathophysiology, but this pattern remains unknown in patients with Brugada syndrome. METHODS: and Results A total of 12 consecutive Brugada syndrome patients (46+/-14 years, all male) who underwent implantation of an implantable cardioverter defibrillator were studied. The distribution of the time of ventricular fibrillation detection was examined and classified into four 6-hour time periods of the day. The mean follow-up period following implantation was 777+/-535 days. In six out of the 12 patients, ventricular fibrillation occurred during follow-up. The data logs revealed that ventricular fibrillation was detected 30 times (range, 3-9). Ventricular fibrillation was observed more frequently at night ( 1800 h to 0600 h) than in the day (0600 h to 1800 h) (93.3% [28/30] vs 6.7%[2/30], P<0.001), and during sleep than while awake (86.7% [26/30] vs 13.3%[4/30], P<0.001). Ventricular fibrillation occurred most frequently between midnight and 0600 h in patients with ventricular fibrillation episodes during sleep (76.9% [20/26] vs 23.1%[6/26], P<0.01). CONCLUSION: These results suggest that increased nocturnal vagal activity and withdrawal sympathetic activity may play an important role in the arrhythmogenesis of the Brugada syndrome.

Adult↗
PubMed1999

Reduced urination rate while drinking beer with an unpleasant taste and off-flavor.

A lowered subjective evaluation of the taste and flavor of beer due to staleness or to the addition of an unpleasant taste and flavor was found to be closely correlated with the urination rate. Beer in the same lot was compared immediately after shipment from the brewery and after leaving at room temperature for 1 month or 5 months. Each beer sample was given to volunteers at the rate of 3 ml/kg/15 min for 2 hours, and the urine volume was measured every 30 minutes. The urination rate was highest from the volunteers who drank fresh beer and lowest from those who drank 5-month-old beer. The subjective evaluation of both the taste and drinkability of 5-month-old beer was significantly lower than that of fresh beer. Beer samples with various unpleasant taste and flavor substances added lowered the urination rate. The results suggest that the perception of an unpleasant taste and off-flavor would lower the urination rate.

Adult↗
PubMed1999

[Non-invasive continuous hemodynamic measurement during operation for a child with coarctation of aorta].

For non-invasive hemodynamic monitoring, DYNEMO 3000 (SOMETEC Inc) has a 10 mHz ultrasonic echo scan and a 5 mHz Doppler velocimeter connected to an echo-oesophageal probe allowing continuous measurement of the aortic diameter and of the blood flow velocity in the descending aorta. This device thus can only measure the aortic blood flow, but also calculate the stroke volume and the systemic vascular resistance. Moreover, the systolic time intervals and the length of the pre-ejection period can be measured with the oscillometric tensiometer and the electrocardiography. This paper describes a case in which this device was used for a child with coarctation of the aorta. The hemodynamic changes were measured continuously during coarctectomy. During the temporary bypass, the aortic blood flow and the stroke volume decreased, but on the other hand, the total vascular resistance increased at the same time. After the bypass, these parameters returned to the values before the bypass. We think that this device is useful as a non-invasive monitor to observe the hemodynamic changes continuously during operation for a child with congenital heart disease.

Adolescent↗
PubMed1999

[Relationship between ALDH2 genotypes and choice of alcoholic beverages].

There are obviously individual differences in the choice for many kinds of alcoholic beverages such as beer, wine, whisky, sake, cocktail and so on. It is generally believed that these differences are related to acquired preferences in taste and smell, in addition to life style. However, the basis of these acquired preferences is not yet understood. It has been shown that around half of Japanese show a marked sensitivity to alcoholic beverages because of aversive reactions due to a catalytic deficiency in ALDH2 isozyme. Therefore, differences in ALDH2 genotypes may possibly influence the choice of alcoholic beverages because the individuals possessing the ALDH2*2 gene may prefer the alcoholic beverages containing lower concentrations of alcohol. A large population survey (320 males, 132 females) was conducted using questionnaires to investigate the relationship between ALDH2 genotypes and the choice of alcoholic beverages. Individuals with the homozygote of ALDH2*1 generally showed more preference for alcoholic beverages containing a higher concentration of alcohol than those with the heterozygote or the homozygote of ALDH2*2. It was noted that the latter groups preferred whisky and water, and sweet cocktails. Also, the choices for beer, whisky, and sake were significantly different between both genders. Our data suggested that individuals with ALDH2*2 prefer beverages with lower concentrations of alcohol due to an aversive reaction after drinking, and that there are obvious gender differences in the consumption as well as the choice for many alcoholic beverages.

Adult↗
PubMed1998

Diagnostic value of plasma levels of brain natriuretic peptide in arrhythmogenic right ventricular dysplasia.

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by local or diffuse wall motion abnormalities in the right ventricle (RV), associated with recurrent ventricular tachycardia (VT) of RV origin. Brain natriuretic peptide (BNP) was first isolated from a porcine brain extract. In humans, BNP is expressed predominantly in the ventricles of failing hearts, and its expression has been observed primarily in myocytes in the interstitial fibrous area in dilated cardiomyopathy. We hypothesized that BNP is increasingly secreted from the residual myocytes within the atrophic tissue in patients with ARVD. METHODS AND RESULTS: Plasma BNP levels were measured in 17 patients with ARVD, 12 patients with idiopathic RV outflow tract tachycardia (RVOT), and 120 control subjects. We performed cardiac catheterization, RV endomyocardial biopsy, electron- beam CT, and biventricular endomyocardial mapping in the ARVD patients. There was a significant increase in plasma BNP levels in the ARVD patients compared with the RVOT patients and control subjects (61.4+/-59.6 pg/mL versus 8.3+/-5. 5 pg/mL and 9.3+/-5.8 pg/mL; P<0.0001, respectively). The plasma BNP levels had no correlation with any of the hemodynamic data, but they had a significant correlation with the RV ejection fraction (r=-0. 588, P=0.025) and with the fractionated-area scores (r=0.705, P=0. 005). Light microscopic immunohistochemistry showed strong BNP immunoreactivity in residual myocytes with fibrofatty replacement. CONCLUSIONS: These results suggest that plasma BNP levels were not increased in RVOT patients but were increased in ARVD patients, and that the increased BNP levels indicate the severity of both the RV dysfunction and the arrhythmogenic substrate.

Adolescent↗
PubMed1998

Localization of optimal ablation site of idiopathic ventricular tachycardia from right and left ventricular outflow tract by body surface ECG.

BACKGROUND: Idiopathic ventricular tachycardia (VT) is known to arise from the right ventricular (RV) and left ventricular outflow tracts (LVOT). However, reliable noninvasive methods to localize the optimum ablation site for VT have not been reported. METHODS AND RESULTS: Body surface maps (BSM) and 12-lead ECGs were investigated in 35 VTs from the RVOT and 5 VTs from the LVOT in which the origin was confirmed during the ablation procedure. The RVOT was classified into 8 subdivisions with the use of a 3-dimensional anatomic relation: anterior (A) posterior (P), right (R) left (L), and superior (S) inferior (I). On the BSM, the following 3 indexes differentiated each location of the origin, with a diagnostic accuracy of 88% (A-P), 92% (R-L), and 77% (S-I): (1) the location of the minimum at the early-to-mid QRS (right, A; left, P), (2) the isopotential distribution in the left shoulder area after 30 ms of QRS (positive, R; negative, L), and (3) the downward moving time of the minimum at the early-to-mid QRS (>/=50 ms, S; <50 ms, I). On the 12-lead ECG, (1) the QRS duration (>140 ms, A; </=140 ms, P) and the R-wave pattern in leads II and III (RR' or Rr', A, R, P), (2) the QS wave amplitude in aVR and aVL (aVR>/=aVL, R; aVR /=1 in lead V3 was an index suggesting the LVOT origin. CONCLUSIONS: The origin or the optimum ablation site of idiopathic VT from RVOT and LVOT can be localized with the use of indexes obtained with a BSM or 12-lead ECG.

Adolescent↗
PubMed1998

Analysis of HLA-DQ alpha sequences for prenatal diagnosis in single fetal cells from maternal blood.

We have extended a previously developed method that allows prenatal DNA diagnosis of female fetuses through the isolation of single nucleated erythrocytes from maternal blood by developing a method that can distinguish between maternal and fetal nucleated erythrocytes. Nucleated erythrocytes were separated by a density-gradient method and then collected by micromanipulation. Sex was determined after primer extension preamplification (PEP) of the entire genome of a single cell, and human leukocyte antigen (HLA)-DQ alpha type was determined after further amplification of this gene. The HLA-DQ alpha genotype of fetal erythrocytes in maternal blood samples and their corresponding paternal and maternal lymphocytes were successfully determined in all cases. The accuracy of the method was determined by using single nucleated erythrocytes from umbilical cord blood from five normal deliveries. This is the first demonstration that the fetal HLA-DQ alpha gene sequences can be identified in a small aliquot of a single nucleated erythrocyte in maternal blood. We believe that this method ushers in a new era in which the reliability and accuracy of noninvasive prenatal DNA diagnosis from maternal blood is markedly improved.

Alleles↗
PubMed1998

Prenatal diagnosis of ornithine transcarbamylase deficiency by using a single nucleated erythrocyte from maternal blood.

We have developed a method that allows the prenatal DNA diagnosis of ornithine transcarbamylase (OTC) deficiency by using a single fetal nucleated erythrocyte (NRBC) isolated from maternal blood. OTC gene analysis of a male patient (TF) with early onset OTC deficiency was performed by single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing. To investigate the possible prenatal diagnosis of OTC deficiency, maternal blood was obtained at 13 weeks of gestation of a subsequent pregnancy, from the mother of patient TF. NRBCs in the maternal blood were separated by using the density gradient method and then collected with a micromanipulator. The entire genome of a single NRBC was amplified by primer extension preamplification (PEP). The human leukocyte antigen (HLA)-DQ alpha genotype and sex were determined from small aliquots of the PEP product. The HLA-DQ alpha genotype of each of the parents of the male patient was also determined. Once a single NRBC had been identified as being of fetal origin, the OTC gene was analyzed by using the restriction fragment length polymorphism (RFLP) method. DNA analysis revealed a point mutation in exon 9 of the OTC gene in the OTC-deficient patient (TF). All NRBCs retrieved from maternal blood were successfully identified as being of fetal origin by HLA-DQ alpha genotyping and sex determination. RFLP analysis demonstrated that the fetal OTC gene was normal. This is the first study to successfully diagnose OTC deficiency prenatally, by using a single fetal NRBC from the maternal circulation. Such prenatal DNA diagnosis is non-invasive and can be applied to other genetic diseases, including autosomal and X-linked diseases.

Erythrocytes↗