Search PubMed⌕ Search

Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 829 records · Page 46Linked to original sources
PubMed1984

Conformational change of sodium- and potassium-dependent adenosine triphosphatase. Conformational evidence for the Post-Albers mechanism in Na+- and K+-dependent hydrolysis of ATP.

The addition of ATP with K+ to pig kidney Na+,K+-ATPase (EC 3.6.1.3) modified with a sulfhydryl fluorescent reagent N-[p-(2-benzimidazolyl)phenyl]maleimide induced a transient decrease (t 1/2 = 0.01 s) in the fluorescence in the presence of Mg2+ with 0.64 M Na+, followed by a slow increase (t 1/2 = 0.08 s), to give a higher steady level than that observed without K+. The addition induced a transient increase (t 1/2 less than 0.02 s) in the amount of phosphoenzyme, followed by a slow decrease (t 1/2 = 0.08 s), but the addition without K+ induced a monophasic increase (t 1/2 = 0.02 s). The addition of ATP in the presence of 2 M Na+ with Ca2+ induced a monophasic decrease (t 1/2 = 0.1 s) in the fluorescence along with a much slower increase (t 1/2 = 1.2 s) in the amount of phosphoenzyme. No significant burst of acid-labile phosphate was observed. The data showed clearly the accumulation of the enzyme-ATP complex preceding the phosphoenzyme formation. Fluorescence intensity of these enzyme species and the amount of phosphoenzyme permitted the simulation using the reaction mechanism including enzyme-ATP complex, ADP-sensitive phosphoenzyme, K+-sensitive phosphoenzyme, and K+-bound enzyme. The simulation gave a good fit to the experimental data which showed that ATP is hydrolyzed in sequence through the above intermediates in the presence of both Na+ and K+.

Animals↗
PubMed1984

Inhibitory effects of various drugs on phorbol myristate acetate and n-formyl methionyl leucyl phenylalanine induced O2- production in polymorphonuclear leukocytes.

To clarify the mechanisms of O2- formation by polymorphonuclear leukocytes (PMNs), the effects of clinically employed drugs on PMNs were investigated by measuring changes in membrane potential and rates of O2- production. These variables were effectively diminished with antihistaminic agents, adrenergic beta-antagonists, and antiarrhythmic drugs when guinea pig peritoneal PMNs were stimulated by either phorbol myristate acetate (PMA) or n-formyl-methionyl-leucyl-phenylalanine (FMLP). The order of potency of the inhibitory effects of these chemicals on the PMA-induced O2- formation was as follows: azelastine (IC50 = 4.1 microM) less than clemastine less than dl-propranolol less than chlorpheniramine maleate less than dichlorisoproterenol less than quinidine less than diphenhydramine less than indomethacin (IC50 greater than 400 microM). Similar phenomena were observed when FMLP was employed instead of PMA, but the FMLP-stimulated O2- production was effectively inhibited by indomethacin. Changes in membrane potential, using the cyanin dye method, also indicated that most of these drugs cancelled functional changes of plasma membrane of PMNs. From these observations, it was demonstrated that changes in membrane potential by the stimuli were essential for the initiation of O2- generation from plasma membrane of PMNs, although the initiation mechanisms were not identical for the two stimuli.

Adrenergic beta-Antagonists↗
PubMed1984

Production of subgroup-specific monoclonal antibodies against human rotaviruses and their application to an enzyme-linked immunosorbent assay for subgroup determination.

Nonneutralizing monoclonal antibodies were prepared against two strains, S2 and YO, of human rotaviruses isolated in cell culture. S2-37 and YO-5 antibodies had subgroup I and subgroup II specificities, respectively. The remaining antibodies (S2-65, YO-71, YO-89, and YO-156) reacted commonly with all the rotaviruses examined. All of the monoclonal antibodies agglutinated exclusively single-shelled particles and immunoprecipitated 42,000-dalton protein, a major component of inner capsid. Using the three monoclonal antibodies (S2-37, YO-5, and YO-156), an enzyme-linked immunosorbent assay was developed for detecting and subgrouping human rotavirus isolates.

Antibodies, Monoclonal↗
PubMed1984

Augmentation of antitumor resistance by a strain of unicellular green algae, Chlorella vulgaris.

Growth of Meth-A tumor in CDF1 mice was inhibited significantly by injection of a hot water extract of a strain of Chlorella vulgaris (CE) into the tumor or into the subcutaneous tissue near the tumor. The augmentation of resistance by CE may require the participation of T cells and macrophages, since it was abolished or reduced in athymic nude mice or mice treated with carrageenan, a macrophage blocker. Mice treated with CE exhibited antigen-specific augmented resistance against rechallenge with tumor. Moreover, the antitumor effect of CE was comparable with that of Corynebacterium parvum, but its mechanism of effect might be different.

Adjuvants, Immunologic↗
PubMed1984

Serotype determination of human rotavirus isolates and antibody prevalence in pediatric population in Hokkaido, Japan.

Three different serotypes of human rotavirus isolates defined in our laboratory were compared by cross neutralization tests with human rotavirus serotypes established in the NIH, U.S.A. The results clearly demonstrated that our three serotypes correspond well to their serotypes Wa, DS-1 and M (or P). Using the three serotype-specific rabbit antisera, all of the 16 strains isolated to date could be assigned to one of those three serotypes. The prevalence of human rotavirus serotypes 1, 2 and 3 among inhabitants of Sapporo and its outskirts was investigated based on the results of neutralizing antibody distribution patterns by age using sera of non-infectious disease patients examined at the Sapporo Medical College Hospital. Neutralizing antibody titers were measured against four strains, KU and K8 (serotype 1), S2 (serotype 2) and YO (serotype 3). The results revealed that serum antibody titers against KU, K8 and YO strains rose with time after birth, reaching the highest antibody distribution levels in either the 3-5-year-old or 6-9-year-old age group, while antibody against S2 strain tended to be lower than that against the other three strains throughout all age ranges examined, with the highest level being shown in the adult group.

Adolescent↗
PubMed1984

Wilms tumor and nephrotic syndrome in male pseudohermaphroditism.

A case is reported of a child with male pseudohermaphroditism in whom Wilms tumor developed at age twenty-two months. The tumor was treated accordingly, but the child subsequently died of nephrotic syndrome with renal failure at age thirty-two months. After reviewing the similar concurrence of these disorders described as a syndrome, it was suggested that they may have basic embryologic abnormalities in common and that all of them originate during embryogenesis. The importance of bearing this syndrome in mind in the management of a child with abnormal gonadal differentiation is stressed.

Disorders of Sex Development↗
PubMed1984

Further characterization of the external urethral sphincter in spinal cord injury: study during spinal shock and evolution of responsiveness to alpha-adrenergic stimulation.

To shed further insight into its ever evolving concepts, we studied the activity of the external urethral sphincter in patients with spinal cord injury. Study during the phase of acute spinal shock revealed persistent electromyographic activity in the external urethral sphincter and no activity in the external anal sphincter, suggesting the presence of functional dissociation between the 2 sphincters from the onset of acute spinal injury. The genesis of dissociated activity was discussed by reference to recent experiments on the individual differences in motor neuron and muscle subtypes. Only the external urethral sphincter of chronic paraplegics demonstrated a uniformly increased electromyographic activity after alpha-adrenergic stimulation, while the response in the external anal sphincter was variable. The mechanism of increased response to alpha-adrenergic stimulation in the denervated external urethral sphincter appears to reside either in direct postsynaptic stimulation or recruitment of motor neurons other than the somatic pudendal system, since pre-treatment with competitive muscle relaxant failed to block this increased response in the external urethral sphincter.

Adrenergic Fibers↗
PubMed1984

T-cell recruitment regulated by prostaglandin-mediated system and its role in immune response.

The dynamics of the number of T cells in spleen and the level of prostaglandin E2 in plasma were investigated serially in mice injected with Corynebacterium parvum. In the first few days, the level of plasma PGE2 increased but decreased to lower than the normal level thereafter. The absolute number of T cells in the spleen began to increase after the PGE2 level dropped. But such an increase of T cells was not observed in ATx mice challenged with C. parvum. Moreover, replenishing the mice with exogenous PGE2 in the period of low PGE2 halted selectively the increase of T cells in the spleen. This enlarged T cell subset responded to PHA, expressed Lyt-1+2+, and was sensitive to PGE2. And this T-cell subpopulation exerted a suppressive effect on antibody response in low PG environment, but lost its inhibitory effect in high PG milieu. These results suggested that an immature T cell subset is recruited from the thymus in a low PG state and participates as regulator cells in immune response at peripheral lymphoid organs.

Animals↗
PubMed1984

In vivo differentiation of cytotoxic T lymphocytes. 1. Serum factor in immunized athymic (nu/nu) mice could differentiate CTL precursor.

Mature cytotoxic T lymphocytes (CTLs) were hardly detected by 51Cr-release assay in the spleen of C3H/He mice after an intravenous injection of spleen cells of C57BL/6 (B6) mice. B6-specific CTL generation was augmented by transfer of sera obtained from C3H/He mice inoculated subcutaneously with EL-4 cells of B6 origin, P815 cells of DBA/2 origin or MH134 cells of C3H/HeN origin or these injected intraperitoneally with sheep or chicken erythrocytes. Such a factor can be produced also by athymic (nu/nu) mice. Such an augmentation of cytotoxicity was detected also in the regional lymph nodes after subcutaneous injection of allogeneic spleen cells. This factor may be different from augmenting factors reported already.

Animals↗
PubMed1984

Thymus-recruited peritoneal exudate T lymphocytes.

The role of the thymus in the generation of antigen-reactive peritoneal exudate T lymphocytes (PETLs) was examined in mice injected with Corynebacterium parvum (C. parvum), which exerted functions as a trigger of T cell recruitment from the thymus and as an antigen to induce antigen-reactive T cells. The proliferative response of antigen-reactive PETLs was higher in sham mice than in adult-thymectomized (ATx) mice 3 weeks after injection of C. parvum. When indomethacin (INDO) was injected simultaneously with an injection of proteose peptone for collecting PETLs, the response to C. parvum decreased to an undetectable level in ATx mice, and to a low but still positive level in sham mice. The addition of PGE2 to the culture suppressed the proliferative response of PETLs from Sham mice, but did not suppress the response of ATx mice. These results suggested the existence of different subsets in antigen-reactive T cells in terms of thymus-dependency and PGE2-dependency or -sensitivity.

Animals↗
PubMed1984

Effects of immunization of mothers on the immune reaction of their offspring: inhibition of immune responses of offspring caused by antibody imported through the milk.

Effects of immunization of pregnant AKR mice with nucleated chicken erythrocytes (CRBC) on immune responses of their offspring were examined. Antigen-specific reduction of generation of cytotoxicity and plaque forming cells (PFC) was demonstrated in the offspring at 8 weeks after birth, and lasted for 15 weeks. Cross-fostering experiments and cell transfer experiments showed that such suppression would be induced by antibody contained in the milk of immunized mothers rather than suppressor cells. Activities to enhance opsonization and to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) were demonstrated in the serum of such offspring before challenge with CRBC. Delayed footpad reaction (DFR) was maintained at the normal level in such offspring of immunized mice.

Animals↗
PubMed1984

Re-evaluation of the indications for cardiac valve replacement.

We re-evaluated the indications for mitral valve replacement and reconstruction, and attempted to determine the optimal time for aortic valve replacement. (1) The actuarial event-free survival rate in patients undergoing open mitral commissurotomy for mitral stenosis with far-advanced subvalvular deformities was 78 per cent at 11 years after surgery and similar in patients undergoing mitral valve replacement for mitral stenosis. Postoperative clinical improvements compared favorably with those in patients undergoing mitral valve replacement. If quality of postoperative life in patients not requiring anticoagulants is borne in mind, open mitral commissurotomy should be given strong consideration as the procedure of choice for the majority of patients with mitral stenosis. (2) The long-term results of reconstructive procedures for mitral regurgitation largely depend upon the pathological anatomies contributing to the development of mitral regurgitation. The results were less satisfactory in patients with fibrotic changes of valvular and subvalvular tissue than in patients undergoing mitral valve replacement for mitral regurgitation. (3) In aortic valve replacement, the postoperative prognosis was poor in patients with a preoperative left ventricular end-systolic volume index exceeding 200 ml/m2 and left ventricular ejection fraction less than 0.35. Operative management of patients with aortic valve disease should be considered, before severe left ventricular systolic dysfunction is evident.

Aortic Valve↗