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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 217 records · Page 12Linked to original sources
PubMed1998

Verapamil-sensitive left anterior fascicular ventricular tachycardia: results of radiofrequency ablation in six patients.

INTRODUCTION: Verapamil-sensitive left ventricular tachycardia (VT) with a right bundle branch block (RBBB) configuration and left-axis deviation has been demonstrated to arise from the left posterior fascicle, and can be cured by catheter ablation guided by Purkinje potentials. Verapamil-sensitive VT with an RBBB configuration and right-axis deviation is rare, and may originate in the left anterior fascicle. METHODS AND RESULTS: Six patients (five men and one woman, mean age 54+/-15 years) with a history of sustained VT with an RBBB configuration and right-axis deviation underwent electrophysiologic study and radiofrequency (RF) ablation. VT was slowed and terminated by intravenous administration of verapamil in all six patients. Left ventricular endocardial mapping during VT identified the earliest ventricular activation in the anterolateral wall of the left ventricle in all patients. RF current delivered to this site suppressed the VT in three patients (ablation at the VT exit). The fused Purkinje potential was recorded at that site, and preceded the QRS complex by 35, 30, and 20 msec, with pace mapping showing an optimal match between the paced rhythm and the clinical VT. In the remaining three patients, RF catheter ablation at the site of the earliest ventricular activation was unsuccessful. In these three patients, Purkinje potential was recorded in the diastolic phase during VT at the mid-anterior left ventricular septum. The Purkinje potential preceded the QRS during VT by 66, 56, and 63 msec, and catheter ablation at these sites was successful (ablation at the zone of slow conduction). During 19 to 46 months of follow-up (mean 32+/-9 months), one patient in the group of ablation at the VT exit had sustained VT with a left bundle branch block configuration and an inferior axis, and one patient in the group of ablation at the zone of slow conduction experienced typical idiopathic VT with an RBBB configuration and left-axis deviation. CONCLUSION: Verapamil-sensitive VT with an RBBB configuration and right-axis deviation originates close to the anterior fascicle. RF catheter ablation can be performed successfully from the VT exit site or the zone of slow conduction where the Purkinje potential was recorded in the diastolic phase.

Adult↗
PubMed1998

Selected slow pathway ablation in a patient with corrected transposition of the great arteries and atrioventricular nodal reentrant tachycardia.

We report the first known case of AV nodal reentrant tachycardia (AVNRT) associated with a corrected transposition of the great arteries to be treated successfully by ablation of the slow pathway. Triple AV nodal pathways were observed in the anterograde direction and two types of AVNRT were induced. Input of the fast pathway to the AV node was located at the anterior portion of the left-sided AV annulus, while the input of the intermediate and slow pathways was located at the anteroseptal portion of the right-sided AV annulus. Radiofrequency energy ablation at the right anteroseptal site eliminated the intermediate and slow pathways.

Atrioventricular Node↗
PubMed1998

Pulp and root development after partial extrusion in immature rat molars: a histopathological study.

Experimental studies were undertaken in immature rat molar teeth to investigate the relationship between root development and the prognosis after partial extrusion. The experimental partial extrusion was induced at 1/2 root formation, 2/3 root formation and 3/4 root formation, using an extrusion device designed by the author. Histopathological studies and SEM observation of the pulpal tissue in rat maxillary first molars with partially formed roots after partial extrusion were conducted and evaluated. The degree of extrusion was changed according to the development of the root to produce a similar luxated state. The rats were sacrificed immediately after experimental extrusion, immediately after operation, and after 3 days, 7 days, 14 days, 30 days, and 60 days to compare the histopathological and SEM findings between experimental groups and control groups. Immediately after the extrusive injury, ablations of the odontoblast layer from dentin were seen with retention of a fluid component in the ablated spaces in the pulp. On 1 and 3 days after surgery, cellular components such as erythrocytes and leukocytes due to bleeding were seen. Ablations of the odontoblast layer were seen in the coronal pulp most frequently in the pulp horn, cervical area and floor of the pulp chamber. In general, pulp reaction after extrusion in groups with more complete root formation was more severe than in groups with less complete root formation. It is suggested that the more complete the root formation, the greater the effect on the pulp as result of partial extrusion, while with less complete root formation, the greater the malformation of the root apices.

Animals↗
PubMed1998

Analysis of diversity of mutations in the mecI gene and mecA promoter/operator region of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

Genomic diversity of mutation in the mecI gene or mecA promoter/operator region was analyzed for clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE). In most MRSA strains, a single base substitution was detected in either the mecI (three different positions) or the mecA promoter (two different positions), while a 28-base deletion in mecI was found in one strain. In contrast, no mutation was detected in these gene sequences of MRSE strains.

Bacterial Proteins↗
PubMed1998

Detection and characterization of novel rotavirus strains in the United States.

We recently established a rotavirus strain surveillance system in the United States to monitor the prevalent G serotypes before and after the anticipated implementation of a vaccination program against rotavirus and to identify the emergence of uncommon strains. In this study, we examined 348 rotavirus strains obtained in 1996 to 1997 from children with diarrhea in 10 U.S. cities. Strains were characterized for P and G types, subgroups, and electropherotypes by using a combination of monoclonal antibody immunoassay, reverse transcription-PCR, and hybridization. The four strains most commonly found worldwide comprised 83% of the isolates (P[8]G1, 66.4%; P[4]G2, 8.3%; P[8]G3, 6.9%; P[8]G4, 1.4%), but 9.2% were unusual strains (P[6]G9, 5.5%; P[8]G9, 1.7%; P[6]G1, 1.4%; and P[4]G1 and P[8]G2, 0. 3% each). Strains not typeable for P or G type accounted for 5.5% of the total, while 2.3% of the strains had more than one G type (mixed infections). All P[6]G9 strains tested had short electropherotypes and subgroup I specificity and were detected in 4 of 10 cities, while P[8]G9 strains had long electropherotypes and subgroup II VP6 antigens. Both sequence analysis of the VP7 open reading frame (about 94 to 95% amino acid identity with the VP7 gene of G9 prototype strain WI61) and binding to a G9-specific monoclonal antibody strongly suggest that U.S. G9 strains belong to serotype G9. The high detection rates of unusual rotaviruses with G9 (7.2%) or P[6] (6.9%) specificity in multiple U.S. cities suggest the emergence of new strains or inadequate diagnosis in the past. The epidemiologic importance of these strains remains to be determined.

Antibodies, Monoclonal↗
PubMed1998

Improved oxygen utilization during mild exercise in heart failure.

In heart failure with low cardiac output, exercise tolerance is reduced despite modulated regional blood distribution and oxygen extraction. However, low cardiac output does not necessarily lead to reduced exercise tolerance especially during mild exercise. In the present study, in order to understand the mechanisms regulating exercise tolerance in heart failure, we measured oxygen consumption (VO2) and cardiac output (CO) during both mild and intense exercise. Patients with heart failure were divided into 2 groups; group L (n = 8) consists of patients with low anaerobic threshold (AT) < 13 ml/min per kg and group H (n = 7) consisting of patients with AT > 13 ml/min per kg. At rest, VO2 was similar between groups L and H, whereas CO was lower in group L than in group H (3.5 + 0.3 vs 4.8 + 1.4 ml/min, p < 0.01). Increase in VO2 during warm-up exercise was not significant between the 2 groups (7.4 +/- 0.5 (group L) vs 6.2 +/- 0.3 ml/min per kg (group H), ns), but increase in CO was lower in group L than in group H (2.5 +/- 0.6 vs 3.4 +/- 0.4 ml/min, p < 0.01). After warm-up to the AT point, however, the increase in not only VO2 but also CO was markedly reduced in group L than in group H (VO2: 0.5 +/- 0.4 vs 3.7 +/- 0.8 ml/min per kg, p < 0.01, CO: 0.2 +/- 0.3 vs 1.1 +/- 0.3 L/min, p < 0.01). Based on these measurements, we calculated the arteriovenous oxygen difference (c(A-V)O2 difference) during exercise in individual patients using Fick's equation. The c(A-V)O2 difference was markedly increased in severe heart failure during the warm-up stage, but between the end of warm-up and the AT point, it remained at the same level as that of group H. These results suggest the presence of a unique mechanism regulating the c(A-V)O2 difference in severe heart failure patients, activation of which may, at least during mild exercise, contribute to efficient oxygen delivery to the peripheral tissues thus compensating for the jeopardized exercise tolerance in those patients.

Aged↗
PubMed1998

Does binding of ouabain to human alpha1-subunit of Na+, K+-ATPase affect the ATPase activity of adjacent rat alpha1-subunit?

To ascertain whether ouabain binding to human alpha1-subunit influences coexpression of rat alpha1-subunit, the ouabain-sensitive profiles of Na+,K+-ATPase activity and 86Rb+ uptake activity and ouabain binding capacity were measured in HeLa cells stably expressing rat alpha1-subunit. The ouabain-sensitive profile of ATPase and 86Rb+ uptake activity seemed to be the sum of two components, one with high and one with low apparent affinity to ouabain, which were similar to that observed in HeLa and NRK-52E cells derived from human and rat, respectively. The ATPase activity with low sensitivity to ouabain increased in simple proportion to the amount of the rat alpha1 mRNA derived from transfected cDNA, which was determined by the reverse transcription-polymerase chain reaction method. The turnover number of the human Na+,K+-ATPase activity obtained from the ratio of the Na+,K+-ATPase activity to the ouabain binding capacity is about 150/sec. The expression of the rat alpha1-subunit had no effect on the turnover numbers of the Na+,K+-ATPase activity with high affinity to ouabain estimated from the ouabain binding capacity as the active site concentration. These results suggested that the ouabain bound to human alpha1-subunit did not inhibit the ATPase activity of the coexpressing rat alpha1 in these cells.

Animals↗
PubMed1998

Difference in susceptibility to CC-chemokines among HIV-1 isolates.

In this study, we examined the difference in susceptibility to anti-HIV activity of the CC-chemokines (RANTES, MIP-1 alpha and MIP-1 beta) among HIV-1 isolates and analysed its relation with phenotype (syncytium inducibility) and V3 domain of gp120 of the HIV-1 isolates. Of 11 cases tested in endogenous assay, at a concentration of 200 ng/ml, RANTES, MIP-1 alpha, and MIP-1 beta showed more than 80% suppression of HIV-1 replication in 10, 8, and 7 cases, respectively. HIV-1 isolates sensitive to more than one CC-chemokine showed non-syncytium-inducing phenotype, whereas HIV-1 isolates resistant to all of the 3 CC-chemokines showed syncytium-inducing phenotype. HIV-1 isolates resistant to all of the 3 CC-chemokines contained more positively charged amino acid residues in the V3 domain of the gp120. These results indicated that utilization of the CC-chemokine receptors as co-receptors for virus entry could vary among HIV-1 isolates.

CD4-Positive T-Lymphocytes↗
PubMed1998

Lectin-binding patterns in the olfactory epithelium and vomeronasal organ of the common marmoset.

The patterns of expression of sugar residues in the olfactory epithelium and vomeronasal organ of the common marmoset were studied lectin-histochemically. Eight lectins including DBA, BSL-I, RCA-I, s-WGA, PNA, ECL, UEA-I and Con A bound to the free border of the olfactory epithelium, and 6 lectins including DBA, RCA-I, s-WGA, PNA, ECL and UEA-I bound to that of the vomeronasal organ. UEA-I bound to all dendrites of the olfactory receptor cells, and 6 lectins including BSL-I, RCA-I, s-WGA, PNA, ECL and Con A bound to only a part of dendrites of the olfactory receptor cells. ECL and UEA-I bound to all dendrites of the vomeronasal receptor cells, and s-WGA, PNA and Con A bound to only a part of dendrites of the vomeronasal receptor cells. Seven lectins including RCA-I, s-WGA, BSL-II, PNA, ECL, UEA-I and Con A bound to all the olfactory receptor cell bodies, and BSL-I bound to only a part of them. Six lectins including RCA-I, s-WGA, PNA, ECL, UEA-I and Con A bound to all the vomeronasal receptor cell bodies, and BSL-II bound to only a part of them. These results showed that a smaller number of lectins bound to the free border, dendrites and cell bodies of the receptor cells in the vomeronasal organ than those in the olfactory epithelium, suggesting that the vomeronasal organ is less active in some physiological functions with which sugar residues are associated than the olfactory epithelium in the common marmoset.

Animals↗
PubMed1998

Evaluation of highly sensitive thyrotropin assay for detecting thyroid diseases in neonatal screening: preliminary studies.

TSH concentrations in dried blood samples on filter paper were determined by a conventional enzyme-linked immunosorbent assay (ELISA), used for routine neonatal screening for primary hypothyroidism, and a highly sensitive bioluminescence ELISA (BL-ELISA) using firefly luciferase to examine whether central hypothyroidism and hyperthyroidism can be efficiently detected as cases of primary hypothyroidism. Samples were obtained from 3 patients with congenital central hypothyroidism, 5 patients with congenital primary hypothyroidism, 6 patients with hyperthyroidism, 31 neonatal babies with low birth weight (premature babies) and 242 newborn babies with normal birth weight from the general population (normal babies). The TSH values were low in central hypothyroidism and hyperthyroidism. Their deviations from the mean TSH value for normal babies by the BL-ELISA method (-3.12 SD and -4.79 SD in central hypothyroidism and hyperthyroidism respectively) were greater than those by the ELISA method (-2.00 SD and -2.97 SD respectively). The TSH values were high in primary hypothyroidism and normal in premature babies while deviations were the same when BL-ELISA and ELISA were used. These findings indicate that the highly sensitive TSH assay (BL-ELISA) can be used for detecting both primary and central hypothyroidism as well as hyperthyroidism in neonatal screening.

Adult↗
PubMed1998

Electron microscopic study of intercalated duct cells in the chicken pancreatic islet and effects of tolbutamide administration.

Intercalated duct cells are present in the alpha and beta islets of chicken. The intercalated duct cells adhere to each other via intercellular junctional complexes at the apical side, projecting many microvilli and a few cilia into the lumen. They also extend slender cytoplasmic processes between the islet endocrine cells. These intercalated cells appear to have a stellate form, and to wrap their cytoplasm around endocrine cells. Administration of tolbutamide led to increased electron density in the cytoplasm of intercalated duct cells. Lysosomes are present in these cells in various numbers and sizes and tend to increase with time after administration of tolbutamide. These observations suggested that the intercalated ducts not only pass through the islet, but also play a role in supplying islet cells.

Animals↗
PubMed1998

Risk factors for the prevalence of malnutrition among urban children in Ghana.

A case-control study was completed at the Princess Marie Louise Hospital in Accra, Ghana, to identify risk factors for the prevalence of underweight and severe malnutrition in urban African children. A total of 170 children, aged 8 to 36 mo, with normally nutritional status (> or = 80% W/A of NCHS reference), underweight (moderate malnutrition) (60-80% W/A), or severe malnutrition (< 80% W/A and presence of edema, or < 60% of W/A) were recruited at the clinical ward and at the public health service section of the hospital. Anthropometric measurements and physical examinations were completed, and the guardians were interviewed about their children's health status, birth weight, child care, and household conditions. The severely malnourished children were more likely to have young mothers (p < 0.05) and low weight at birth (p < 0.05). The underweight children were also observed to have low birth weight (p < 0.05). The severely malnourished group showed the tendencies of less feeding frequency (p < 0.01), less access to breast-feeding (p < 0.01), and less support by both parents (p < 0.05). Moreover, the parents of the severely malnourished children had lower educational levels and lower income jobs, compared with those of the normal children (mother's education, p < 0.001; father's education, p < 0.001; mother's occupation, p < 0.05; father's occupation, p < 0.001). No significant differences in most variables existed between the normal and underweight groups. Multivariable analysis resulted in the conclusion that the Z-score of weight-for-age, birth weight, and mother's educational level were highly associated with one another. We conclude that low birth weight is one of the important risk factors for the prevalence of underweight and severe malnutrition and that the lack of a mother's education is also a risk factor for the prevalence of severe malnutrition in the urban children in Ghana.

Adolescent↗
PubMed1998

Pathologic characterization of hypotensive C57BL/6J-agt: angiotensinogen-deficient C57BL/6J mice.

a fpreviously produced angiotensinogen-deficient mice, i.e. mice with deleted renin-angiotensin system (RAS), with a genetic background on C57BL/6J - C57BL/6J-agt (-/-) -, but no C57BL/6J-agt (-/-) which survived long enough to be weaned. In the present study, we attempted to prevent neonatal death and analyzed pathological development in C57BL/6J-agt (-/-). We indicate that mortality in C57BL/6J-agt (-/-) derived from C57BL/6J-agt (+/-) can be reduced by hypodermic saline injection in the 7 days following birth, that hydronephrosis developed by day 14 in association with polydiplasia and polyuria by day 30, and that chronic hypotension occurs. Hydronephrosis is less damaging to electrolyte resorption in younger mice, but not in adults. We also observed that C57BL/6J-agt (-/-) derived from C57BL/6J-agt (-/-) frequently develop fetal hydronephrosis and die of respiratory failure at birth. These results suggest that maternal RAS is associated with structural maturation of kidney and lung in late fetus and that postnatal RAS plays important roles in structural and functional maintenance of the kidneys.

Angiotensinogen↗
PubMed1998

Enchondromatosis with features of dysspondyloenchondromatosis and Maffucci syndrome.

We report a girl with multiple enchondromatosis, unequal leg length, short stature, congenital scoliosis, lymphangioma, and cutaneous hemangiomata. The skeletal findings were consistent with the clinical and radiological features of dysspondyloenchondromatosis except that short stature was not apparent in the neonatal period. Dysspondyloenchondromatosis is a rare disorder, one of the several types of multiple enchondromatosis with spinal abnormalities. In previous reports of this condition the association of vascular lesions usually found in Maffucci syndrome has not been described.

Child↗
PubMed1998

[The relationship between maintenance dose of vecuronium and the recovery time from the muscle relaxation].

We investigated the relationship between maintenance bolus dose of vecuronium bromide (Vb) and the recovery time measured by TOF Guard in patients anesthetized with isoflurane (1.2-2.0%)-N2O-O2 (GOI group, n = 19) and epidural anesthesia (2% mepivacaine) plus isoflurane (0.5%)-N2O-O2 (EPI group, n = 14). In both groups, anesthesia was induced with propofol 2 mg.kg-1 and Vb 0.1 mg.kg-1 and ventilation was controlled to keep end tidal CO2 between 35-40 mmHg. When the muscle relaxation recovered to 25% of train-of four ratio (TOFR), doses of Vb 0.06, 0.04 or 0.02 mg.kg-1 were administered. Recovery time to TOFR 25% at each Vb dose (T 0.06, T 0.04 and T 0.02 respectively) was observed. T 0.02, T 0.04 and T 0.06 in GOI group were 36.7 +/- 3.2, 50.7 +/- 4.3 and 60.7 +/- 5.02 min (mean +/- SE), respectively and those in EPI group were 42.6 +/- 2.53, 52.2 +/- 2.51 and 59.9 +/- 3.22 min, respectively. There were no significant differences in the recovery time between these two groups. In both groups, although the recovery time to TOFR 25% was prolonged significantly in proportion to the increasing doses of Vb, the increase did not correlate with the dose of Vb. We suggest that frequent administration of Vb 0.02 mg.kg-1 decreases the total amount of Vb to keep TOFR within 25%.

Aged↗
PubMed1998

Interleukin-9 receptor alpha chain mRNA formation in CD8+ T cells producing anti-human immunodeficiency virus type 1 substance(s).

A search for gene(s) associated with anti-human immunodeficiency virus type 1 (HIV-1) activity of CD8+ T cells was attempted using molecular cloning and the relation between the anti-HIV activity of CD8+ T cells and the interleukin-9 receptor alpha chain (IL-9R-alpha) mRNA expression from the cDNA clones obtained was examined. The anti-HIV-1 activity of CD8+ T cell culture supernatants was assessed by measuring the level of HIV-1 replication of a CD4+ T cell line transfected with an infectious HIV-1 DNA clone. IL-9R-alpha mRNA was assayed by reverse transcriptase-polymerase chain reaction (RT-PCR). Of 5 cases showing high level of anti-HIV-1 activity (more than 80% suppression of HIV-1 replication), the mRNA was detected in 4 cases. Of 10 cases showing low level of anti-HIV-1 activity (less than 80% suppression of HIV-1 replication), the mRNA was detected in one case. Soluble recombinant human IL-9 receptor (rhIL-9sR) did not suppress HIV-1 replication at a concentration of 1 microgram/ml. These data suggest that the IL-9R-alpha mRNA formation in CD8+ T cells may correlate with and play some role in the anti-HIV-1 activity of CD8+ T cells from HIV-1-infected individuals.

CD4-Positive T-Lymphocytes↗
PubMed1998

[Aortic regurgitation with stenosis due to congenitally bicuspid valve with fibrous band: a surgical case report].

A 62-year-old man with aortic regurgitation and stenosis underwent aortic valve replacement. Intraoperative findings showed fibrous band between the edge of the raphe and the ascending aorta. Such fibrous bands are usually observed in juvenile pure aortic valve regurgitation due to congenitally bicuspid valve with degenerative change and are related to cause aortic insufficiency. The present patient was comparatively old, and the aortic regurgitation was combined with stenosis, which revealed sclerotic change on histological examination.

Aortic Valve↗