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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 199 records · Page 11Linked to original sources
PubMed1998

Fine structure of three types of olfactory organs in Xenopus laevis.

There is no report on the fine structure of three types of olfactory organs in Xenopus laevis. Their functional assignments in olfaction are not yet established. The fine structure of three types of olfactory organs, olfactory epithelium (OE), vomeronasal organ (VNO), and middle chamber epithelium (MCE), was examined in Xenopus laevis by light and electron microscopy. The olfactory cells of the OE and the sensory cells of the VNO were equipped with cilia and microvilli, respectively, similar to terrestrial animals that possess both the OE and the VNO. On the other hand, the sensory cells of the MCE were classified into two types, the sensory cells with cilia and the sensory cells with microvilli, like those of the OE in fish. These findings suggest that the OE and the VNO in Xenopus laevis detect different kinds of odoriferous molecules in air, whereas the MCE is involved in the perception of odorants in water.

Animals↗
PubMed1998

Immunohistochemical and enzyme-histochemical study on the accessory olfactory bulb of the dog.

The accessory olfactory bulb (AOB) is a primary center of the vomeronasal system. In the dog, the position and morphology of the AOB remained vague for a long time. Recently, the morphological characteristics of the dog AOB were demonstrated by means of lectin-histochemical, histological, and immunohistochemical staining, although the distribution of each kind of neuron, especially granule cells, remains controversial in the dog AOB. In the present study, we examined the distribution of neuronal elements in the dog AOB by means of immunohistochemical and enzyme-histochemical staining. Horizontal paraffin or frozen sections of the dog AOB were immunostained with antisera against protein gene product 9.5 (PGP 9.5), brain nitric oxide synthase (NOS), glutamic acid decarboxylase (GAD), tyrosine hydroxylase (TH), substance P (SP), and vasoactive intestinal polypeptide (VIP) by avidin-biotin peroxidase complex method. In addition, frozen sections were stained enzyme-histochemically for NADPH-diaphorase. In the dog AOB, vomeronasal nerve fibers, glomeruli, and mitral/tufted cells were PGP 9.5-immunopositive. Mitral/tufted cells were observed in the glomerular layer (GL) and the neuronal cell layer (NCL). In the NCL, a small number of NOS-, GAD-, and SP-immunopositive and NADPH-diaphorase positive granule cells were observed. In the GL, GAD-, TH-, and VIP-immunopositive periglomerular cells were observed. In the GL and the NCL, TH-, and VIP-immunopositive short axon cells were also observed. In addition to these neurons, TH- and SP-immunopositive afferent fibers were observed in the GL and the NCL. We could distinctly demonstrate the distribution of neuronal elements in the dog AOB. Since only a small number of granule cells were present in the dog AOB, the dog AOB did not display such a well-developed GCL as observed in the other mammals.

Animals↗
PubMed1998

Slight difference in primary amino acid sequence of p17 matrix protein of HIV-1 exerts profound influence on its antigenicity.

HIV-1 p17 antigen has been studied for its biological significance in vitro as well as its immunological roles in vivo. By immunological approach of antibody-binding to HIV-1 p17 antigens of several subtypes in combination with computerized analysis of those tertial structures, it became evident that, irrelevant of similarity of linear amino acid sequence of different HIV-1 subtypes, a few amino acid substitutions close to or distant from specified epitope(s) affected their tertial structure resulting in change in ability of its binding to selected antibody. ELISA employing two monoclonal antibodies, A144 and C415, could detect p17 of subtypes A and B, but not of subtypes C, D, and E. Since the epitope site corresponding to A144 has been reported to be important for biological activity of p17 of HIV-1, change in tertial structure around this epitope may explain some difference in biology of HIV-1, such as infectivity of subtypes B and E.

Amino Acid Sequence↗
PubMed1998

Gelatin-induced T-cell activation in children with nonanaphylactic-type reactions to vaccines containing gelatin.

BACKGROUND: Many cases of anaphylactic or nonanaphylactic reactions have been reported to measles-mumps-rubella vaccine or its component vaccines that contain gelatin as a stabilizer. Increased levels of specific IgE antibodies to gelatin have been reported in children with anaphylactic reactions. However, IgE is not increased in cases of nonanaphylactic reaction, and the mechanisms of the reaction are still controversial. OBJECTIVE: The study was aimed to elucidate the relationship between nonanaphylactic reaction and gelatin. METHODS: We investigated in vitro induction of activated memory helper T cells (CD4(+ )CD25(+ )CD45RO+ cells) in response to gelatin in children with nonanaphylactic reactions to vaccines containing gelatin. RESULTS: In patients with delayed-type sensitivity to gelatin confirmed with a positive skin test response, CD4(+ )CD25(+ )CD45RO+ cells were significantly more strongly induced in culture containing gelatin than in control cultures. However, there was no significant difference between cultures with gelatin and those with control solvent in patients without reactions after vaccination. Of 76 patients with nonanaphylactic reactions after immunization with vaccine containing gelatin, 61 had an increased lymphocyte stimulation index to gelatin versus control children. CONCLUSION: These results suggest the possibility that nonanaphylactic reactions to gelatin-containing vaccine in Japan might be mediated by delayed hypersensitivity reactions against gelatin.

Anaphylaxis↗
PubMed1998

Preferential selection of heterologous G3-VP7 gene in the genetic background of simian rotavirus SA11 detected by using a homotypic single-VP7 gene-substitution reassortant.

Introduction of segmented genomes into virion is an important process in viral replication of rotavirus. We previously studied the assortment of the VP7 gene segment (encoding outer capsid protein VP7) in the genetic background of simian rotavirus SA11 (G serotype 3, G3) and found the preferential selection of homologous G3 VP7 gene over VP7 gene of heterologous G serotype (G1, G2 or G4). In the present study, in order to clarify whether or not VP7 gene derived from different G3 rotavirus (heterologous G3-VP7 gene) is also preferentially selected in the SA11 background, a single-VP7 gene-substitution reassortant was prepared from SA11 through multiple steps of coinfection with rotaviruses in vitro. The isolated reassortant, SNR1, possessed VP7 gene derived from canine G3 rotavirus K9 and all other gene segments of SA11 origin, and showed an identical growth characteristic to that of SA11. Amino acid sequence of K9 VP7 gene showed a high degree of identity (93.6%) to SA11 VP7 gene. In analysis by mixed infection and multiple passages of SNR1 and a single VP7 gene (with G1, G2 or G4 specificity) reassortant in the SA11 background, the G3-VP7 gene became predominant at early passage numbers. However, in mixed infection with SA11 and SNR1, homologous G3-VP7 gene (SA11-VP7 gene) was preferentially selected into progenies over heterologous one (K9-VP7 gene). These results together with our previous findings suggested that G3-VP7 gene, irrespective of origin of species, was functionally adapted to the genetic background of SA11, although the homologous gene had a better fit with other SA11 genes than did heterologous one, providing suggestions for efficaciousness of multivalent reassortant rotavirus vaccine.

Amino Acid Substitution↗
PubMed1998

Surgical treatment for aortic regurgitation and left ventricular dysfunction caused by Kawasaki disease.

A 10-year-old girl required replacement of the aortic valve because of massive regurgitation caused by Kawasaki disease at the age of 3 months. Postoperatively, left ventricular function and mass improved remarkably, with reduction of both hypertrophy and interstitial fibrosis. During a follow-up period of 10 years, she has been free from any cardiac event.

Aortic Valve Insufficiency↗
PubMed1998

Sequence of DNA replication in Allium fistulosum chromosomes during S-phase.

Bromodeoxyuridine pulse labelling and immunodetection were applied to synchronized Allium fistulosum cells to study sequential changes in the chromosome replication pattern during S-phase. The replication patterns were classified into five main types depending on the location of the replication signals: (1) over the whole chromosomes; (2) at proximal and interstitial regions; (3) at proximal, interstitial and distal regions; (4) at interstitial and distal regions; and (5) at distal regions. The frequencies of each pattern changed sequentially according to the timing of BrdU incorporation, demonstrating the temporal order of chromosome replication during S-phase. The distal regions that correspond to the major C-bands replicated throughout S-phase except for the earliest stage, but most intensely in late S-phase. The replication time of different chromosome sites overlapped, which is quite different from the biphasic mode of replication that occurs in mammalian chromosomes.

Allium↗
PubMed1998

Humoral and cell-mediated immunity in malnourished children in Ghana.

OBJECTIVE: To examine the relationship between immunological variables and the different types and severity of malnutrition in Ghanaian children. DESIGN: Case-control study. SETTING: The study was done at Princess Marie Louise Hospital, Accra, Ghana. SUBJECTS: One hundred and seventy children, aged 8-36 months, were recruited at the clinical ward and public health service section of the hospital: 61 normal children, 49 moderately malnourished (underweight) children and 60 severely malnourished children (19 kwashiorkor, 30 marasmus, and 11 marasmic kwashiorkor children). METHOD: The children underwent clinical observations, anthropometric measurements and blood sampling for biochemical analysis to evaluate their nutritional and immunological status. Serum immunoglobulins (IgA subclasses, IgG subclasses and IgM), complements (C3 and C4) and lymphocyte subpopulations (T cells, B cells, CD4+, CD8+, NK cells and HLADR) were determined for the assessment of humoral and cell-mediated immunity. RESULTS: Serum levels of IgA1, IgA2 and C4 tended to be higher in severely malnourished children than in normal children, while serum level of C3 and the proportion of B cells were significantly lower in the severely malnourished children than in the normal children (P < 0.05). There were no notable differences in most immunological parameters among the three severely malnourished groups. No differences were observed in the immunological parameters except for the proportion of B cells between normal and moderately malnourished children. Factor analysis revealed that C3 levels were positively correlated with a factor which was strongly associated with weight-for-height z-score and biochemical indicators for evaluating protein nutrition. In addition, IgA2, IgG1 and IgM levels were positively correlated with a factor which was associated with C-reactive protein. CONCLUSION: Several immunological variables responded positively or negatively with the different levels of severity of malnutrition, but most variables did not on the different types of malnutrition. The changes of C3 level were more associated with the severity of malnutrition.

Antibody Formation↗
PubMed1998

Postinfarction left-ventricular aneurysm: regional stress, function, and remodeling after aneurysmectomy.

BACKGROUND: Left-ventricular (LV) aneurysm formation after myocardial infarction (MI) leads to LV remodeling with global and regional cardiac dysfunction. LV aneurysmectomy (LVA) can often improve LV function, but changes of regional wall stress and systolic function in the noninfarcted segment before and after the operation remain poorly understood. The purpose of this study was to assess the effects of LVA on regional stress and systolic function in the noninfarcted region and to examine this procedure's impact on the LV remodeling in patients with LV aneurysm after myocardial infarction (MI). METHODS: Using quantitative left ventriculography and pressure measurements, 11 patients with an anterior LV aneurysm were studied before and 8 months after standard linear repair (LVA group), and 10 patients with an anterior transmural infarction who received coronary artery bypass grafting were also studied (CABG group) in an attempt to separate the effects of aneurysmectomy from the effects of bypass surgery. Regional end-systolic (ESS) and end-diastolic (EDS) stresses of the contractile segment (CS) were computed by Janz's method. RESULTS: The total ejection fraction (EF) increased (p < 0.01) in the LVA group, whereas it did not change in the CABG group at 8 months after surgery. Both the end-diastolic and end-systolic volume indices of CS decreased (p < 0.01 and p < 0.01, respectively) in the LVA group, whereas both remained unchanged in the CABG group. The mean velocity of circumferential fiber shortening (mean Vcf) of CS increased substantially (p < 0.01) in the LVA group and, less significantly (p < 0.05), in the CABG group. Regional ESS and EDS decreased (p < 0.01 and p < 0.05, respectively) in the LVA group, whereas both remained unchanged in the CABG group. The increase in mean Vcf correlated strongly with the magnitude of decrease in ESS (r = -0.63, p < 0.01) in the LVA group but not in the CABG group. CONCLUSIONS: LVA can reduce regional afterload and improve ejection performance of the noninfarcted myocardium in many patients with a large anterior LV aneurysm and, moreover, may favorably affect the LV remodeling process after MI.

Cardiac Catheterization↗
PubMed1998

Mutations in the canilicular multispecific organic anion transporter (cMOAT) gene, a novel ABC transporter, in patients with hyperbilirubinemia II/Dubin-Johnson syndrome.

Members of the ATP-binding cassette (ABC) transporter superfamily are mutated to cause diseases that include cystic fibrosis, hyperinsulinemia, adrenoleukodystrophy, Stargardt disease and multidrug resistance. We recently isolated a novel human member of ABC transporter superfamily as the candidate transporter for the glucuronide and glutathione-conjugated antitumor agents, and found it highly homologous to the rat cmoat gene. consistent with recent findings of defects in the homologous cmoat gene in two rat models of hyperbilirubinemia (TR- and Eisai), we report two deletions and a missense mutation in the active transport family signature region in the gene in patients with hyperbilirubinemia II/Dubin-Johnson syndrome (DJS; MIM 237500), respectively. These results strongly implicate the cMOAT gene as responsible for the defects in DJS patients.

Amino Acid Sequence↗
PubMed1998

Fluorescein 5'-isothiocyanate-modified Na+, K+ -ATPase, at Lys-501 of the alpha-chain, accepts ATP independent of pyridoxal 5'-diphospho-5'-adenosine modification at Lys-480.

The modification of Na+,K+-ATPase with increasing pyridoxal 5'-diphospho-5'-adenosine (AP2PL) concentrations resulted in saturation of the approximately 0.5 mol AP2PL probe incorporation into the Lys-480/mol catalytic alpha-chain and reduced the Na+,K+-ATPase activity to around half without affecting the phosphorylation by acetyl phosphate (AcP), and led to increases in the AP2PL fluorescence caused by ATP and AcP. Further modification with fluorescein 5'-isothiocyanate (FITC) resulted in approximately 0.9 mol FITC probe incorporation into the Lys-501/mol alpha-chain and reduced the activity to below 5% without affecting the phosphorylation by AcP and these fluorescence increases. The ATP binding capacity of the AP2PL-FITC enzyme was shown to be at least 50% of that of the control enzyme (approximately 0.8 mol/mol alpha-chain). This is the first direct demonstration that Na+-bound FITC-modified enzymes accept ATP with an affinity for ATP (K(1/2) > 150 microM) reduced by two orders of magnitude. The data also suggest half site reactivity of Lys-480 as to AP2PL and all site reactivity of Lys-501 as to FITC in the catalytic subunits.

Adenosine Diphosphate↗
PubMed1998

Effects of isosorbide dinitrate on oxygen uptake kinetics in cardiac patients.

PURPOSE: Although nitrates are known to improve indices of exercise capacity in patients with coronary artery disease, their effects on oxygen uptake kinetics during the onset of exercise have not been clarified. We evaluated the acute effects of isosorbide dinitrate on the kinetics of oxygen uptake during the onset of exercise at a constant work rate in patients with coronary artery disease. METHODS: We studied 14 patients with coronary artery disease who performed 6 min of low-intensity exercise at a constant work rate on a cycle ergometer 30 min after oral administration of 10 mg of isosorbide dinitrate or placebo in a double-blind, crossover manner. Oxygen uptake was calculated from breath-by-breath analysis of respired gases. The time constant of oxygen uptake kinetics during the onset of exercise was determined by fitting a single exponential function to the oxygen uptake response. RESULTS: Heart rate was significantly increased at rest, and systolic blood pressure was significantly decreased both at rest and during exercise after administration of isosorbide dinitrate. The time constant of oxygen uptake was significantly shorter (the kinetics were faster) after administration of isosorbide dinitrate (39.4+/-10.1 vs 44.5+/-10.5 s, P = 0.038). CONCLUSIONS: Isosorbide dinitrate was found to speed the kinetics of the increase in oxygen uptake during constant work-rate exercise. The time constant of oxygen uptake, which reflects the rapidity of cardiovascular adaptation at the onset of exercise, seems to be a useful parameter of the effectiveness of therapy in patients with coronary artery disease.

Adult↗
PubMed1998

Resistance to oxyimino beta-lactams due to a mutation of chromosomal beta-lactamase in Citrobacter freundii.

The duplicative mutation of an Ala-Val-Arg sequence at positions 208 to 210 in the loop structure of Enterobacter cloacae class C beta-lactamase caused substrate specificity extension to oxyimino beta-lactam antibiotics and this chromosomal mutation provided bacterial cells with high resistance to the beta-lactams (M. Nukaga et al, 1995, J. Biol. Chem. 270, 5729-5735). In order to confirm the universality of this phenomenon among other class C beta-lactamases, the duplicative mutation was applied to a class C beta-lactamase of Citrobacter freundii, which has 74% homology to the E. cloacae beta-lactamase amino acid sequence. The counterpart sequence to the Ala-Val-Arg of the E. cloacae enzyme in C. freundii beta-lactamase was identified to be Pro-Val-His. A Pro-Val-His sequence was inserted just after the native Pro-Val-His sequence at positions 208 to 210 in the C. freundii beta-lactamase. The resulting mutant of C. freundii beta-lactamase obtained a striking characteristic that we expected, showing substrate specificity extension to oxyimino beta-lactams. Nearly the same result was obtained with the insertion of an Ala-Val-Arg sequence after the native Pro-Val-His sequence. These results indicate that structural modification of this locus commonly induces modification of the substrate specificity to unfavorable substrates for many chromosomal class C beta-lactamases produced by gram-negative bacteria.

Amino Acid Sequence↗
PubMed1998

Surface marker patterns of T cells and expression of interleukin-2 receptor in measles infection.

The surface marker patterns of T cells of Ghanaian children during measles infection were studied and an attempt was made to demonstrate T cell activation and viability in vitro after activation in vivo by measles virus. The frequencies of CD4+ and CD8+ naive T cells in measles patients were high while their memory T cells were remarkably reduced with no sign of proliferation even at the acute phase of the illness. The reduction of memory T cells was prolonged during the convalescent phase (2 months after onset). The anti-CD3 monoclonal antibody-induced expression of interleukin-2 receptor alpha chain (IL-2R/CD25) was significantly suppressed; however, the addition of phorbol 12-myristate 13-acetate or ionomycin caused a remarkable recovery of CD25 expression. On simple culture, an appreciable proportion of T cells from measles patients died rapidly in contrast with only a few T cells from healthy controls doing so. The suppression of CD25 expression was still demonstrated during the convalescent phase of the disease. Taken together these results suggest unresponsiveness and activation-induced cell death of T cells during severe measles infection in Ghanaian children. Furthermore the prolonged abnormalities of T cells (i.e. decreased memory T cells and inhibition of CD25 expression during the convalescent phase) might be related to post-measles infection immunosuppressive status.

Antigens, Surface↗
PubMed1998

Novel form of atrial tachycardia originating at the atrioventricular annulus.

We report two patients with reentrant atrial tachycardia that originated at the AV annulus. Atrial tachycardia originated in the posterior portion of mitral annulus in one patient (case 1) and the posterolateral portion of tricuspid annulus in one patient (case 2). Tachycardia was successfully eliminated by RF catheter ablation in both patients, with the catheter placed underneath the mitral valve in case 1 and on the tricuspid annulus in case 2. Spiky potentials were recorded in the diastolic phase of the atrium during tachycardia at the sites of successful ablation. Spiky potentials were also recorded after atrial electrogram during sinus rhythm, and showed decremental properties during atrial pacing. An accelerated atrial rhythm was observed during RF application, and tachycardia could not be induced after ablation in either patient. Tachycardia in these patients seemed to be due to reentrant tachycardia originating in the accessory AV node (Mahaim fiber) without ventricular connection.

Action Potentials↗
PubMed1998

Simple electrocardiographic criteria for identifying the site of origin of focal right atrial tachycardia.

UNLABELLED: To construct an algorithm for identifying the precise site of origin of focal right atrial tachycardia (RAT), we analyzed the P wave configuration in 32 patients with RAT who underwent successful radiofrequency catheter ablation. The RA was divided into three areas in the left anterior oblique view: superolateral, inferolateral, and inferomedial. There were 17 RATs arising from the crista terminalis (CT-AT), 12 from the tricuspid annulus (TA-AT), and 3 from the septum away from the TA (Sep-AT). A negative P wave in lead aVR identified CT-AT with a sensitivity (sens) of 100% and a specificity (spec) of 93%. In CT-ATs, positive P waves in the inferior leads differentiated superolateral AT from inferolateral AT with a sens of 86% and a spec of 100%. In any type of AT with inferomedial or inferolateral foci, the P wave deflections in at least one of the inferior leads was negative, and negative P waves in leads V5 and V6 identified inferomedial AT with a sens of 92% and a spec of 100%. In ATs near the apex of Koch's triangle, the P wave duration in the inferior leads was shorter than during sinus rhythm. CONCLUSIONS: (1) the P wave configuration in lead aVR can easily differentiate CT-AT from TA-AT and Sep-AT; (2) the P wave configuration in the inferior leads helps to determine a superior versus inferior origin in any type of AT; (3) in inferior AT, the P wave polarity in leads V5 and V6 is useful in determining a lateral versus medial origin; (4) this algorithm can predict accurately the origin of AT.

Algorithms↗
PubMed1998

Retrograde Purkinje potential activation during sinus rhythm following catheter ablation of idiopathic left ventricular tachycardia.

We describe two patients with idiopathic left ventricular tachycardia that were cured by radiofrequency catheter ablation. Tachycardia was inducible by ventricular stimulation and was verapamil sensitive. Two distinct presystolic potentials (P1 and P2) were recorded during tachycardia in the mid-septal or inferoapical area, but only one potential (P2) was recorded during sinus rhythm. After catheter ablation at this site, the P1 potential was noted after the QRS complex during sinus rhythm, while the P2 was still observed before the QRS complex. The P1 potential showed a decremental property during atrial or ventricular pacing. These data suggest that Purkinje tissue with decremental properties was responsible for the tachycardia mechanism, and that the reentry circuit involving this tissue is likely to be of considerable size.

Anti-Arrhythmia Agents↗