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Biomedical subjects

E Yokota

Publications and source records attributed to E Yokota.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Prosthetic endocarditis caused by Kingella denitrificans in a patient with diabetes mellitus].

Infective endocarditis caused by Kingella denitrificans occurs rarely. A review of the literature reveals only 6 cases of endocarditis caused by the bacillus. K. denitrificans is normally a commensal of the upper respiratory airways, may exceptionally be responsible for endocarditis. A case of possible prosthetic endocarditis caused by K. denitrificans is presented. A 78-year-old male with Type II diabetes was admitted to the hospital complaining of fever, a sore throat and arthralgia. He underwent replacement surgery of a St. Jude medical prosthesis for aortic stenosis at the age of 75. The only physical findings at admission were a temperature of 38.2 degrees C and murmurs of mild mitral regurgitation. The liver and spleen were not palpable, and there were no skin or eye lesions. Laboratory findings were as follows: white blood cell count 9500/microliters with 77% neutrophils, erythrocyte sedimentation rate 71 mm/h (Westergren), blood urea nitrogen 50.2 mg/dl, serum creatinine 1.7 mg/dl and C-reactive protein 22.2 mg/dl. The Gram-negative bacillus isolated from the blood was identified as K. denitrificans by the identification system, namely ID test.FN-20 rapid (Nissui, Japan). Although an echocardiogram detected no vegetation, infective endocarditis was diagnosed because the same bacillus was detected by separate blood cultures and an obvious source of infection was not found other than the prosthetic valve. Initial treatment was flomoxef, which was changed to Ampicillin 2 g/day after K. denitrificans was identified. Ampicillin continued for 6 weeks. The clinical course was good and he did not require further surgery. He has been afebrile for 2 years after completing treatment. This case represents the first report of prosthetic valve endocarditis caused by K. denitrificans in Japan.

Aged↗
PubMed1997

Interaction of flagellar inner arm dynein isolated from sea urchin sperm with microtubules in the presence of ATP.

We have isolated C/A dynein, which is considered to be a component of inner arms, from flagellar axonemes of sea urchin sperm (E. Yokota, I. Mabuchi, J. Cell Sci. 107, 345-351 (1994). C/A dynein binds to and bundles the microtubules in the absence of ATP. In contrast to outer arm 21S dynein, C/A dynein is not released from the microtubules in the presence of ATP (E. Yokota, I. Mabuchi, J. Cell Sci. 107, 353-361 (1994)). We further investigated the interaction of C/A dynein with microtubules in the presence of ATP. The turbidity at 350 nm of a mixture of C/A dynein and microtubules increased by the addition of ATP. Both the initial rate and final extent of the turbidity increase were dependent on C/A dynein or ATP concentration and were inhibited by vanadate. ATP hydrolysis by C/A dynein was linear during the time course of the turbidity increase. Negative staining electron microscopy revealed that microtubular bundles which formed in the presence of C/A dynein became thicker and longer after addition of ATP. Furthermore, sliding movements of microtubule(s) in the individual bundles were observed in the presence of ATP. This mode of interaction of C/A dynein with microtubules was distinct from that of flagellar or ciliary dyneins reported so far. These results suggest that C/A dynein, as a component of inner arms, may play a distinct role in the flagellar movement of sea urchin sperm.

Adenosine Triphosphate↗
PubMed1996

Is outer arm dynein intermediate chain 1 multifunctional?

The outer arm dynein of sea urchin sperm axoneme contains three intermediate chains (IC1, IC2, and IC3; M(r) 128,000, 98,000, and 74,000, respectively). IC2 and IC3 are members of the WD family; the WD motif is responsible for a protein-protein interaction. We describe here the molecular cloning of IC1. IC1 has a unique primary structure, the N-terminal part is homologous to the sequence of thioredoxin, the middle part consists of three repetitive sequences homologous to the sequence of nucleoside diphosphate kinase, and the C-terminal part contains a high proportion of negatively charged glutamic acid residues. Thus, IC1 is a novel dynein intermediate chain distinct from IC2 and IC3 and may be a multifunctional protein. The thioredoxin-related part of IC1 is more closely related to those of two redox-active Chlamydomonas light chains than thioredoxin. Antibodies were prepared against the N-terminal and middle domains of IC1 expressed as His-tagged proteins in bacteria. These antibodies cross-reacted with some dynein polypeptides (potential homologues of IC1) from distantly related species. We propose here that the three intermediate chains are the basic core units of sperm outer arm dynein because of their ubiquitous existence. The recombinant thioredoxin-related part of IC1 and outer arm dyneins from sea urchin and distantly related species were specifically bound to and eluted from a phenylarsine oxide affinity column with 2-mercaptoethanol, indicating that they contain vicinal dithiols competent to undergo reversible oxidation/reduction.

Amino Acid Sequence↗
PubMed1995

Fatal cerebral infarction in an asymptomatic young patient with primary antiphospholipid syndrome.

An 18-year-old woman with primary antiphospholipid syndrome developed a major cerebral infarction leading to brain death despite intensive treatment with steroids, urokinase, glyceol and heparin. Fatal strokes associated with this syndrome are rare. A computed tomographic scan of the brain suggested occlusion of the main trunk of the right middle cerebral artery. The titer of antibodies against cardiolipin/ beta 2-glycoprotein I complex in serum was extremely high.

Adolescent↗
PubMed1994

Isolation and characterization of a novel dynein that contains C and A heavy chains from sea urchin sperm flagellar axonemes.

A novel dynein (C/A dynein), which is composed of C and A heavy chains, two intermediate chains and several light chains, was isolated from sea urchin sperm flagella. The C/A dynein was released by the treatment with 0.7 M NaCl plus 5 mM ATP from the axonemes depleted of outer arm 21 S dynein. Sedimentation coefficient of this dynein was estimated by sucrose density gradient centrifugation to be 22-23 S. The C/A dynein particle appeared to be composed of three distinct domains; two globular head domains and one rod domain as seen by negative staining electron microscopy. The mobility of 'A' heavy chain of C/A dynein on SDS-gel electrophoresis was similar to that of A heavy chains (A alpha and A beta) of 21 S dynein. However, UV-cleavage patterns of C and A heavy chains of C/A dynein were different from those of A heavy chains of 21 S dynein. Furthermore, an antiserum raised against A heavy chain of C/A dynein did not crossreact with A heavy chains of 21 S dynein. Under the conditions in which the C/A dynein was released, some of inner arms were removed concomitantly from axonemes as observed by electron microscopy. These results suggested that C/A dynein is a component of the inner arms.

Animals↗
PubMed1994

C/A dynein isolated from sea urchin sperm flagellar axonemes. Enzymatic properties and interaction with microtubules.

C/A dynein is a novel dynein isolated from sea urchin sperm flagellar axonemes. It is composed of C and A heavy chains and some additional lower molecular mass polypeptide chains. The characterization of ATPase activity and the interaction of this dynein with microtubules polymerized from calf brain tubulin were investigated in this study. The ATPase activity of C/A dynein (0.3-0.4 mumol Pi/min per mg) was about one half that of outer arm 21 S dynein (0.6-0.8 mumol Pi/min per mg) at 25 degrees C. Vanadate inhibited the ATPase activity with a half-maximal inhibition at 1 microM. C/A dynein absorbed to the glass surface was able to translocate the microtubules towards its plus end. The velocity of the microtubule movement in the presence of 1 mM ATP was 4.0 to 4.5 microns/s at 22 degrees C. C/A dynein binds to and bundles the microtubules even in the presence of ATP. Cross-bridges were found between adjacent microtubules in the bundle with an axial periodicity of about 24 nm. The ATPase activity of C/A dynein was enhanced up to several-fold by the microtubules at concentration as low as 1 mg/ml. On the other hand, 21 S dynein bound to the microtubules with 24 nm axial periodicity only in the absence of ATP. Its ATPase activity was not activated by the microtubules. From these results, it is concluded that the manner of interaction with microtubules of C/A dynein is different from that of the outer arm dynein.

Animals↗
PubMed1993

In-vitro evaluation of the four beta-lactamase inhibitors: BRL42715, clavulanic acid, sulbactam, and tazobactam.

The in-vitro synergic activities of BRL42715, a new beta-lactamase inhibitor, clavulanic acid, sulbactam, and tazobactam combined with ampicillin, piperacillin, cephalothin, or cefoperazone were tested against various bacteria producing known types of beta-lactamase. BRL42715 showed the best synergistic activity among the inhibitors tested against strains producing penicillinases of type I, II, III, V, and that from Klebsiella pneumoniae, cephalosporinases, and oxyiminocephalosporinases (except that from Klebsiella oxytoca). Clavulanic acid combined with the beta-lactams tested showed the best synergic activity of the inhibitors against strains producing type IV penicillinase and oxyiminocephalosporinase from K. oxytoca. The 50% inhibitory doses of BRL42715 were superior to those of clavulanic acid against various types of beta-lactamases except for type IV penicillinase and the oxyiminocephalosporinase from K. oxytoca. The inhibitory activity of BRL42715 against cephalosporinases from various bacteria was 10(4) to 10(6)-fold greater than that of clavulanic acid. The synergic effects of BRL42715 and clavulanic acid on the activity of piperacillin were compared against six clinical isolates of bacteria resistant to piperacillin. The synergic activity of BRL42715 was greater than that of clavulanic acid in all six isolates.

Anti-Bacterial Agents↗
PubMed1992

Beta-thalassemia major resulting from a compound heterozygosity for the beta-globin gene mutation: further evidence for multiple origin and migration of the thalassemia gene.

We describe in a Japanese family beta zero-thalassemia resulting from a compound heterozygosity for a beta-globin gene mutation. One mutation is a C-to-T transition at IVS-2 nucleotide position 654 on the background of Mediterranean haplotype IX. Another mutation is a G-to-A transition at IVS-2 nucleotide position 1, associated with a novel haplotype XI. The occurrence of these mutations on various chromosomal backgrounds provides strong evidence for an interplay of gene migration, interallelic gene conversion, and multiple origins of the same mutation.

Adult↗
PubMed1992

[Disappearance of Philadelphia chromosomes after remission induction in lymphoid crisis of chronic myelogenous leukemia].

The authors report a rare case of chronic myelogenous leukemia (CML) in which the Ph1 clone disappeared after remission induction of lymphoid crisis. A 58-year-old man was admitted to our hospital because of fever in July 1988. The white cell count was elevated. Bone marrow aspirate showed hypercellularity with myeloid hyperplasia. In the chromosomal analysis, Ph1 chromosomes were detected in 100% of bone marrow cells analysed. Diagnosis of CML was made and treatment was initiated with recombinant interferon-alpha 2a. Hematological remission without cytogenetic improvement was achieved. In March 1990 he developed lymphoid crisis with proliferation of CD10-positive cells. The chromosomal analysis revealed additional abnormalities including, 45, X, -Y, t(9;22) (q34;q11), +1, -8. With vincristine 0.6 mgX4, pirarubicin 15 mgX4, dexamethasone 40 mgX4 therapy complete remission was obtained. In December 1990 the Ph1 positive clone completely disappeared judging from normal karyotypes in the chromosomal analysis and the disappearance of M-bcr gene rearrangement.

Blast Crisis↗
PubMed1991

Distribution of the HindIII restriction fragment length polymorphism among patients with systemic lupus erythematosus with different concentrations of CR1.

Sixty six patients with systemic lupus erythematosus (SLE) were genotyped using a HindIII restriction fragment length polymorphism identified by CR1.1 cDNA, then were followed up for an average of 50 months to evaluate the stability of their CR1 activities. The gene frequencies for the two alleles which correlate with the numeric expression of CR1 on the erythrocytes were not significantly different between 66 patients with SLE and 52 normal controls. A discrepancy between homozygosity for a high allele and a negative CR1 activity was found in many patients. These patients, however, had significantly lower concentrations of serum complement than did patients with a positive CR1, and some were in an active state of the disease. Furthermore, there were several patients in whom the CR1 activities changed from negative to positive together with an increase in serum complement. Our results suggest that the decreased expression of CR1 on erythrocytes in patients with SLE is not inherited, rather it is a consequence of the disease processes.

Blotting, Southern↗
PubMed1991

[A case of cardiomyopathy due to allergic bronchopulmonary aspergillosis].

We report a rare occurrence of cardiomyopathy associated with allergic bronchopulmonary aspergillosis (ABPA). A 49-year-old man with a history of bronchial asthma was referred to the Matsuyama Red Cross Hospital for evaluation of the abnormal shadow on his chest X-ray. Laboratory examination showed blood eosinophilia and marked elevation of serum IgE concentration and IgE antibody to A fumigatus. The immediate and late skin reactivities to A fumigatus antigen were both positive. The diagnosis of ABPA was made. Treatment using prednisolone was effective in ameliorating the symptoms. However, he was admitted again due to dyspnea, edema and anorexia 6 months later. Chest X-ray, ECG, UCG and scintigraphy suggested severe cardiac failure. The clinical diagnosis of hypertrophic cardiomyopathy, and the pathohistological diagnosis of endomyocardial fibrosis were made by cardiac catheterization and biopsy of endocardium. Retrospectively, cardiomegaly had gradually increased during the past several months while peripheral blood eosinophilia had continued. All these data strongly suggested that eosinophilia due to ABPA might cause severe cardiac damage.

Aspergillosis, Allergic Bronchopulmonary↗
PubMed1990

A common Chinese beta-thalassemia mutation found in a Japanese family.

We have identified the substitution of a thymine for a cytosine at nucleotide position 654 in the second intron of the beta-globin gene that causes beta-thalassemia in a Japanese family. This mutation was reported to occur rather frequently in patients of Chinese origin, but has rarely been found in other ethnic groups.

China↗
PubMed1990

The cAMP-dependent protein kinase in sea urchin sperm tails: association of the enzyme with the flagellar axonemes.

When sea urchin spermatozoa were treated with a Triton X-100 solution, cAMP-dependent protein kinase (cA-kinase) activity was extracted. Further extraction with Triton X-100 of axonemes isolated from the Triton-extracted sperm again released a considerable amount of the cA-kinase activity. The activity which remained after extraction three times with Triton X-100 was released by treatment with a low salt solution. These activities found in the various extracts were likely to be due to the same cA-kinase, which was a mammalian type II-like enzyme. The cA-kinase activity that remained in the axonemes after the first Triton X-100 extraction may be involved in the regulation of flagellar movement in the Triton-extracted sperm.

Animals↗
PubMed1990

[Two cases of amyopathic dermatomyositis with fatal rapidly progressive interstitial pneumonitis].

Two middle-aged women showed typical erythematous heliotrope eruption and Gottron's sign without any symptom of myositis. The patients were diagnosed as 'amyopathic dermatomyositis' because of normal serum CPK levels, normal EMG and no histological abnormality by muscle biopsy. Clinical manifestations improved by the treatment with corticosteroids. During tapering of corticosteroids, however, intersititial pneumonitis developed and rapidly progressed. The first patients was treated with methylprednisolone pulse therapy, azathiopurine and methotrexate. The second patients was treated with betamethazone, methlprednisolone pulse therapy and cyclosporin A. In spite of these extensive immunosuppressive therapies, both patients died of pulmonary insufficiency a few months after admission. In the literature there has been only several cases of amyopathic dermatomyositis and only one case with fatal rapidly progressive interstitial pneumonitis. A new approach to the treatment of this disease should be made.

Autoimmune Diseases↗
PubMed1990

Epidermal growth factor receptor of fibroblasts from patients with scleroderma.

Epidermal growth factor receptor (EGF-R) of fibroblasts from 3 patients with scleroderma (progressive systemic sclerosis, PSS) was studied by radioiodinated-EGF binding assay. The binding was 60.9 +/- 4.0% of normal fibroblasts, and the Scatchard plots showed a decrease in the affinity for EGF, not in the number of EGF-R. PSS fibroblasts expressed higher levels (1.15-2.45-fold) of RNA for the v-erbB (EGF-R gene). All-transretinoic acid (retinoid) had little effect on EGF-R, v-erbB gene expression and the proliferation of PSS fibroblasts. These data concerning the abnormality in the EGF-R may all constitute a feature of PSS fibroblasts.

Cell Division↗
PubMed1990

Successful treatment of refractory systemic lupus erythematosus with intravenous immunoglobulins.

Two cases of refractory systemic lupus erythematosus (SLE) were successfully treated with intravenous immunoglobulins (IVIg). In Case 1, the immediate recovery from severe pancytopenia and the improvement of proteinuria were observed, following IVIg therapy in high doses (450 mg/kg) for 5 consecutive days. In Case 2, 3 courses of IVIg therapy (100 mg/kg) for 6 to 8 days resulted in a significant reduction of massive proteinuria. In both cases, the improvement of immunological variables was also seen.

Adolescent↗