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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 739 records · Page 41Linked to original sources
PubMed1987

Conduction disturbances associated with mitral anular calcification.

To investigate the apparent association of mitral anular calcification (MAC) and electrocardiographic abnormalities, the relation between the location of two-dimensional (2D) echoquantified MAC and conduction disturbances was studied in 140 patients with MAC (MAC group) and 135 age- and sex-matched patients without MAC (control group). The MAC group was subclassified regarding the site and severity of calcium in the mitral anulus. The site of MAC was defined as Type I of MAC near the conduction system and Type II of MAC away from the conduction system. The severity of MAC was graded on 2D echocardiography as mild (localized within 1 segment) and moderate to severe (more than 1 segment). Seven patients with MAC, and only one control subject, had pacemakers in place. Conduction disturbances were present in 44 (31%) of 140 patients with MAC and in 37 (27%) of the 135 control patients (no significant difference). But there were more conduction disturbances in the patients with Type 1 MAC (53%) than in those with Type II MAC (26%) (p less than 0.01). Specifically, complete left bundle branch block and intraventricular conduction delay were more prevalent when MAC was near the conduction system. Intraventricular conduction delay also was more prevalent in the patients with Type I MAC than in the control group (Type I: 12% vs control: 4%; p less than 0.05). These data suggest that moderate to severe degrees of MAC located near the conduction system are associated with conduction disturbances, especially intraventricular conduction delay.

Aged↗
PubMed1987

[Behavior of left ventricular filling after left ventricular aneurysmectomy: evaluation by pulsed Doppler echocardiography].

The pattern of diastolic flow velocity was studied using pulsed Doppler echocardiography to evaluate postoperative left ventricular (LV) diastolic function in patients who underwent left ventricular aneurysmectomy. This study involved 16 patients who experienced ischemic heart disease from January 1985 to April 1986. The patients were categorized in two groups; the aneurysm group comprised by seven patients undergoing aneurysmectomy, and the bypass group which included nine patients undergoing only coronary artery bypass grafting. Pulsed Doppler studies were performed five to 22 days before, and at an average of 12 days after surgery. Preoperative cardiac catheterization and cineangiography were performed and, myocardial infarct size was estimated by the Wagner's method. Using pulsed Doppler echocardiography, LV filling dynamics were assessed by the peak velocity in the rapid filling phase (R), the peak velocity in the atrial contraction phase (A), and the ratio of A to R (A/R ratio) of the mitral flow velocity pattern. All data were average in five consecutive beats. 1. The estimated myocardial infarct size (%MI) in both groups before surgery was 38.5% in the aneurysm group and 32.5% in the bypass group, and there was no significant difference between these groups. 2. The preoperative cardiac index (2.9 in the aneurysm group vs 2.8 1/min/m2 in the bypass group), left ventricular end-diastolic pressure (16.1 vs 17.3 mmHg), and left ventricular ejection fraction (0.43 vs 0.36) were not significantly different between the two groups. 3. The preoperative A/R ratio was 1.5 in the aneurysm group and this was significantly higher than that of the bypass group (1.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Problems in the modified Fontan operation for univentricular heart of the right ventricular type.

Thirteen patients (ages 4 to 16 years) with univentricular heart of right ventricular type, nine with double-inlet right ventricle (DIRV), and four with mitral atresia who underwent a modified Fontan operation were reviewed. Among those with DIRV, right isomerism with a common atrioventricular (AV) valve was found in eight and situs inversus in one; among those with mitral atresia, AV discordance was found in two and concordance in two. Intra-atrial routing using a baffle with atriopulmonary anastomosis was the main procedure (11 patients). There were two operative deaths (one DIRV, one mitral atresia) and three hospital deaths, with an early mortality of 38.5% overall (DIRV 44%, mitral atresia 25%). Low cardiac output was the main cause of death, with relatively high right atrial pressure and with tachyarrhythmias in most of the patients. Mortality was 75% for patients with DIRV who had total anomalous pulmonary venous drainage (n = 4) and 20% for those without (n = 5). Preoperative ventricular volume and ejection fraction were not different between those with severely low cardiac output (n = 4, three deaths) and the others, whereas ventricular mass/volume ratio was significantly lower in the former group. Two late deaths (one DIRV, one mitral atresia) related to the AV valve regurgitation. These results may indicate a relatively poor outcome after the modified Fontan operation for patients with univentricular heart of right ventricular type as a result of basic anatomic and hemodynamic problems.

Arteriovenous Shunt, Surgical↗
PubMed1987

Reconsiderations of indications for open mitral commissurotomy based on pathologic features of the stenosed mitral valve. A fourteen-year follow-up study in 347 consecutive patients.

From January 1972 to December 1984, 347 consecutive patients underwent open mitral commissurotomy for mitral stenosis. Commissurotomy was performed in 86% of 404 patients undergoing mitral valve operations for stenosis during the same period. These 347 patients had three different types of mitral stenosis: type I, mobile cusps without subvalvular changes (43 patients); type II, thickened cusps with subvalvular changes (210 patients); type III, rigid cusps with severe subvalvular changes (94 patients). Concomitant mild mitral regurgitation was seen in 87 patients (25.1%) and mild to moderate valve calcification in 61 patients (17.6%). There were eight early deaths (2.3%) and 12 late deaths (3.5%), yielding an actuarial survival rate of 94.6% (excluding early deaths) 14 years after operation. There were 17 reoperations (5.0%) The actuarial rates of freedom from reoperation were as follows: 83.8% at 14 years for the entire series; 73.5% for type I stenosis; 88.9% for type II; 84.0% for type III; 91.7% for mitral stenosis with calcification; 82.6% for stenosis without calcification; 90.6% for pure mitral stenosis; and 52.5% for stenosis combined with regurgitation (p less than 0.05). Postoperative effective mitral valve areas calculated according to the hydraulic formula were 2.52 cm2 (mean) at rest and 3.06 cm2 during exercise in six patients with type I stenosis, 2.21 and 2.48 cm2, respectively, in 10 with type II, and 1.85 and 1.87 cm2, respectively, in 14 with type III. Our data clearly demonstrated that open mitral commissurotomy provided excellent long-term results with acceptable valve function and a low incidence of reoperation in patients with pure mitral stenosis not combined with regurgitation, even when associated with severe subvalvular changes with or without mild to moderate valve calcification.

Adolescent↗
PubMed1986

Identification of N-[p-(2-benzimidazolyl)phenyl]maleimide-modified residue participating in dynamic fluorescence changes accompanying Na+,K+-dependent ATP hydrolysis.

Na+,K+-ATPase from pig kidney was specifically modified with a sulfhydryl fluorescent reagent, N-[p-(2-benzimidazolyl)phenyl]maleimide (BIPM), by pretreatment of N-ethylmaleimide. The preparation thus obtained retained 100% of initial Na+,K+-ATPase activity and contained 1 BIPM residue/alpha-chain, and it showed almost 2-fold larger fluorescence changes accompanying ATP hydrolysis than the previous preparations which retained 60% of initial activity and contained 3-4 BIPM residues/alpha-chain (Taniguchi, K., Suzuki, K., and Iida, S. (1982) J. Biol. Chem. 257, 10659-10667). Extensive trypsin (Sigma type I) treatment of the new preparation produced mainly two different fluorescent peptide peaks in both ion-exchange and reverse-phase chromatography. Amino acid sequence analysis of both peptides showed that they had the same common sequence, Ser-Tyr-X-Pro-Gly-Met-Gly-Val, except that the larger one contained Ala-Leu next to the Val residue. From the comparison of the amino acid sequence deduced from cDNA from sheep kidney (Shull, G. E., Schwartz, A., and Lingrel, J. B. (1985) Nature 316, 691-695), X was shown to correspond to Cys-964 of the alpha-chain in Na+,K+-ATPase. The data suggest that the microenvironment of the BIPM residue covalently bound to the sulfhydryl group of Cys-964 changes accompanying sequential appearance of reaction intermediates of Na+,K+-ATPase.

Adenosine Triphosphate↗
PubMed1986

Protective effect of naturally acquired homotypic and heterotypic rotavirus antibodies.

To assess serotype specificity of immune resistance to rotavirus gastroenteritis, the relation between pre-existing neutralising antibodies to homotypic and heterotypic rotaviruses and protection against infection or clinical illness was investigated. The subjects were 44 orphans exposed once or twice to consecutive outbreaks of gastroenteritis due to type 3 rotavirus in an orphanage in Sapporo. Sera were collected throughout these outbreaks and the serum levels of neutralising antibodies against four different serotypes of group A human rotavirus were measured before and after the outbreaks. Protection against rotavirus gastroenteritis seemed to be serotype specific and to be related to levels of antibody against homotypic virus. A neutralising antibody level of 1/128 or greater seemed to be protective. The protective effect was of short duration, which was probably the explanation for recurrent attacks of gastroenteritis due to a rotavirus of the same serotype. Seroconversions or concomitant antibody responses to type 1 or 4 rotavirus in most children with type 3 rotavirus infection suggested that immunity to heterotypic virus can be induced by a rotavirus vaccine.

Antibodies, Heterophile↗
PubMed1986

Synergistic defense system by cooperative natural effectors against metastasis of B16 melanoma cells in H-2-associated control: different behavior of H-2+ and H-2- cells in metastatic processes.

H-2+ and H-2- cells of B16 melanoma were established by repeated fluorescence-activated cell sorting. The H-2- line formed no metastasis in untreated C57BL/6 mice, whereas the H-2+ cells showed evidence of metastatic development. This difference was ascribed mainly to the increased susceptibility of H-2- cells to attack by natural effector mechanisms, particularly asialo GM1+ NK cells. After treatment with both anti-asialo GM1 serum and whole body irradiation (400 rad), numerous colonies of H-2- cells formed in the lung, whereas the metastasis was only marginally enhanced by irradiation and moderately by treatment with anti-asialo GM1 serum. With the H-2+ cells, treatment with each modality significantly increased the number of metastatic colonies. Therefore collaboration of asialo GM1+ NK cells and radiosensitive natural effectors seems to be the main mechanism involved in the synergistic effects on defense against H-2- cell metastasis, and to a lesser extent against H-2+ cell metastasis. Irradiation (1000 rad) to the right lung to abrogate the organ-associated defense increased the colonies, particularly in the H-2+ cells. On the other hand, treatment with anti-asialo GM1 serum increased colonization in the early phase of metastasis with H-2- cells and may have abolished asialo GM1+ NK cells capable of recognizing the reduced expression of H-2 antigens and eliminating H-2- cells in the blood-born phase. Natural defense mechanisms probably exert suppressive effects on the metastasis of H-2+ cells, mainly in the organ-associated phase after extravasation.

Animals↗
PubMed1986

Reversible change in light scattering following formation of ADP-sensitive phosphoenzyme in Na+,K+-ATPase modified with N-[p-(2-benzimidazolyl)phenyl]maleimide.

An increase in light scattering (3.5 +/- 0.2%) was observed when pig kidney Na+,K+-ATPase preparations modified with N-[p-(2-benzimidazolyl)phenyl] maleimide were phosphorylated by ATP in the presence of 2 M Na+ with Mg2+ to form ADP-sensitive phosphoenzyme (E1P), which had a negative fluorescence intensity (-1.5 +/- 0.3%). Addition of K+ or ouabain to E1P reduced the light scattering to the original level observed in the absence of ATP. Stopped flow measurements showed that the fluorescence change accompanying the E1P formation (t1/2 = 0.1 s) occurred preceding the light-scattering change (t1/2 = 1 s). Oligomycin affected the rate of the scattering increase little, but it diminished the effect of K+ on E1P to reduce the light scattering and increase the fluorescence. The addition of 2 M Na+ to K+-sensitive phosphoenzyme (E2P) immediately decreased the fluorescence (t1/2 = 0.02 s) to form E1P which was followed by a slow increase in the light scattering (t1/2 = 0.25 s). Oligomycin reduced both rates of the above changes accompanying the transition of E2P to E1P. The data suggest the sequential appearance of species of E1P that precede E2P formation during the hydrolysis of ATP.

Adenosine Diphosphate↗
PubMed1986

T cell recruitment from the thymus to the spleen in tumor-bearing mice. I. Analysis of recruited cells by surface markers.

After inoculation of tumor cells (methylcholanthrene-induced sarcoma), the number of Thy 1+ cells and PNA (peanut agglutinin) binding cells, which were shown to be different subpopulations were increased in the spleen of thymus-intact mice, in contrast this increase was not observed in adult thymectomized mice. In experiments performed concurrently with splenic cell analysis, we found that the plasma PGE2 levels declined in parallel with the tumor growth. Prevention of such a decline of plasma PGE2 level by replenishment with exogenous PGE2 inhibited the splenic cell increase in tumor bearers. In the tumor-bearing mice, cell traffic systems from the thymus to the periphery was ascertained by injecting fluorescein diacetate (FDA) into the thymus and observing fluorescein positive cells in the periphery. We suggest that increased recruitment of thymic cells to the periphery may be mediated by PGE2 in the presence of a tumor.

Animals↗