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Biomedical subjects

N Ohta

Publications and source records attributed to N Ohta.

At least 145 records · Page 8Linked to original sources
PubMed1994

Physical map of the plastid genome of the unicellular red alga Cyanidium caldarium strain RK-1.

The physical map of the plasmid genome of the unicellular red alga Cyanidium caldarium strain RK-1 was constructed. The 150-kbp genome was circular and had an inverted repeated region (IR) which contained the genes for 16 s and 23 s ribosomal RNAs, as is usually seen in most plastid genomes. Since C. caldarium is a very "primitive" alga, the results suggest that the ancestral cyanobacteria lost most of its genome as an endosymbiont comparatively early in the process of plastid formation. After that, several genes seem to have been lost from plastid genomes, step by step, during the course of evolution.

Amino Acid Sequence↗
PubMed1994

The trpA gene on the plastid genome of Cyanidium caldarium strain RK-1.

The trpA gene (for the alpha subunit of tryptophan synthase) was found on the plastid genome of the "primitive" unicellular red alga Cyanidium caldarium strain RK-1. This is the first example of an actively-transcribed gene for tryptophan synthase encoded on a plastid genome. In contrast to trpA, trpB (the gene for the beta subunit of tryptophan synthase) was encoded in the cell nucleus. Considering the primitive characteristics of C. caldarium, trpB must have been lost from the plastid genome before trpA.

Amino Acid Sequence↗
PubMed1994

Acanthamoeba-specific human T-cell clones isolated from healthy individuals.

T-cell responses to pathogenic free-living amoebae, Acanthamoeba sp., were analyzed in healthy Japanese individuals. Of 20 healthy subjects, 10 (50%) showed significant proliferative responses of peripheral blood mononuclear cells to the soluble amoebic antigens in vitro. The antigens used were not mitogenic, and no evidence of amoebic superantigens was available. We established human T-cell clones reactive to Acanthamoeba, all of which were CD3- and CD4-positive, CD8-negative, and TCR-alpha beta-positive. We isolated two strains of Acanthamoeba from two patients, one from a patient with meningoencephalitis (CSF strain) and the other from a patient with keratitis (K strain). Of 13 clones, 11 were reactive to the K-strain as well as to the CSF-strain antigen under human leukocyte antigen (HLA)-DR restriction, whereas the other two were specific for the K-strain antigen. All but one clone tested showed TH1-equivalent functions because these cells produced interferon (IFN)-gamma in response to the amoebic antigen but produced no detectable level of interleukin 4 (IL-4). These results suggest that immunocompetent hosts might have acquired protective immunity mediated by Acanthamoeba-specific T-cells during natural sensitization.

Acanthamoeba↗
PubMed1994

Population analysis of cellular responses to synthetic peptides of Der p II, a major allergen molecule of Dermatophagoides pteronyssinus, in allergic and nonallergic subjects.

Responses of peripheral blood mononuclear cells to synthetic oligopeptides of Der p II, one of the major allergen molecules of Dermatophagoides pteronyssinus, were compared between allergic and nonallergic subjects. Healthy subjects showed positive responses to crude extracts of D. pteronyssinus, but only allergic subjects showed elevated cellular responses to Der p II. We synthesized three oligopeptides of Der p II in which motifs of a possible T-cell epitope were included. Of 14 subjects with positive response to Der p II, three responded to all three peptides, while five did not respond to any peptide tested. In 11 allergic patients who showed positive response to Der p II, responsiveness to the peptide K33-T47 was significantly higher than that to other peptides (P < 0.05). All the responding patients were also positive for scratch test to Der p II, suggesting that those epitopes induced IgE-promoting helper T-cell response in allergic persons. On the other hand, the in vitro cellular responses were not necessarily correlated to IgE production against Der p II in healthy subjects.

Adolescent↗
PubMed1994

Clonal expansion of CD8+ cytotoxic T lymphocytes against human T cell lymphotropic virus type I (HTLV-I) genome products in HTLV-I-associated myelopathy/tropical spastic paraparesis patients.

Short-term culture of peripheral blood mononuclear cells (PBMC) derived from patients with human T cell lymphotropic virus type I-associated myelopathy (HAM)/tropical spastic paraparesis resulted in dominance by DR+ activated CD8+ T cells. Variations in the T cell receptor (TCR) V alpha and V beta chains in these cells were analyzed, and in all 10 patients examined, 2-3 V gene families were dominant in both TCR V alpha and V beta. In five patients we examined, cultured lymphocytes contained cytotoxic lymphocytes for p40tax (patients HAM2, 3, 7, and 8) or env protein (patient HAM4) of human T lymphotropic virus type I. In patients HAM2 and HAM8, cultured lymphocytes contained a large proportion of V beta 8+ CD8+ and/or V beta 12+ CD8+ cells. The sequence of V beta 8+ and V beta 12+ cDNA revealed that they were oligoclonal with identical or similar sequences in each patient. Elimination experiments with monoclonal antibodies for TCR V beta 8 and V beta 12 showed that they were CD8+ cytotoxic T lymphocytes (CTL) for p40tax. In addition, flow cytometry and sequencing analysis of uncultured PBMC revealed that in HAM2, V beta 8+ CTL and their precursors account for 7% and V beta 12+ CTL and their precursors account for 18% of total CD8+ cells. This indicates the presence of two markedly expanded clones in vivo. No common dominant TCR V alpha or V beta were observed among 10 HAM patients analyzed.

Amino Acid Sequence↗
PubMed1994

Binding and aggregation of human gamma-globulin by cis-diamminedichloroplatinum(II) through disulfide bond.

The incubation of gamma-globulin with cis-diamminedichloroplatinum (II) (cis-DDP) resulted in gradual formation of insoluble aggregates. Since the precipitates, composed of polymerized gamma-globulin and cis-DDP, were completely solubilized with urea, the reaction mixture containing precipitate was examined in terms of the binding of cis-DDP and the effect on disulfide (S-S) bonds in the gamma-globulin. When gamma-globulin was incubated with 30 molar excess cis-DDP at pH 7.4 and 37 degrees C, cis-DDP gradually bound to as much as 12 mol per mol of gamma-globulin in 14 d. Concurrently, about four disulfide bonds were cleaved without reaching a certain plateau. An sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the aggregated gamma-globulin induced by cis-DDP was significantly different from that of the heat-denaturated aggregate form or the reduced form by sulfitolysis. The aquated complexes of cis-DDP also produced an insoluble precipitate and affected the S-S bond to a greater extent than the parent drug.

Cisplatin↗
PubMed1994

Effects of supernatant from tonsillar cell culture on neutrophil functions.

The palatine tonsil is the most important element of Waldeyer's ring as a defense mechanism against various microorganisms. The neutrophils are the initial active participants in bacterial infection and inflammation, but their interaction with other cellular participants is poorly understood. To clarify this point, the effects of culture supernatant from human tonsillar cells on the peripheral neutrophil function were investigated. Supernatants from tonsillar cells were incubated in the presence or absence of streptococcal preparation (OK-432) enhanced chemiluminescence, adherence, phagocytosis, chemotaxis, and superoxide production of human peripheral neutrophils. The results suggest that tonsils play an important role in the regulation of neutrophil function.

Bacterial Infections↗
PubMed1994

Neutrophil activating activity of tonsillar cells from patients with tonsillitis.

The previous paper demonstrated that tonsillar cells cultured in vitro in the presence or absence of a streptococcal preparation, OK-432, produce factors that activate various neutrophil functions. In the present study, examination was made of the factor productivity of tonsillar cells from patients with chronic tonsillitis of varying severity, and palmoplantar pustulosis (PPP). Tonsillar cells from patients with severe tonsillitis and PPP incubated with culture medium alone produced a much greater amount of active factors compared with those from patients with mild tonsillitis. When tonsillar cells were incubated in the presence of OK-432, augmentation in factor production by the addition of OK-432 was less in former than latter cases, suggesting that factor production from tonsils correlates with the course of inflammation in this organ.

Adolescent↗
PubMed1994

Detection of anti-neutrophil cytoplasmic antibodies (ANCA) using the immunoperoxidase method.

Anti-neutrophil cytoplasmic antibodies (ANCA), which are present in Wegener's granulomatosis (WG) and other systemic vasculitis, were detected using the immunoperoxidase method rather than the indirect immunofluorescence method. It was possible to distinguish ANCA patterns (c-ANCA, p-ANCA) by the immunoperoxidase method. When neutrophil smears were treated with 0.4% hydrogen peroxide solution, the endogenous peroxidase activity was sufficiently inhibited. ANCA was also detected, using HL-60 cells (human promyelocytic leukemia) and THP-1 cells (human myelocytic leukemia) as substrates.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1994

Eosinophil and eosinophil cationic protein in allergic rhinitis.

To evaluate the roles of eosinophils in allergic rhinitis, eosinophil cationic protein (ECP) levels in sera and nasal secretions were measured in 28 patients with allergic rhinitis. In patients, blood eosinophil counts and serum ECP levels were significantly higher than in controls (p < 0.05). However, there was no statistically significant correlation between blood eosinophil count and serum ECP level (r = 0.025). The number of eosinophils and the ECP level in nasal secretion were also measured. In patients, the ECP level increased with the number of eosinophils, and the ECP level in nasal secretion was significantly higher than in controls (p < 0.05). These results suggest that eosinophils and ECP play important roles in allergic rhinitis.

Adolescent↗
PubMed1994

Interaction of antistasin-related peptides with factor Xa: identification of a core inhibitory sequence.

Antistasin, isolated from the Mexican leech, is a 119 amino acid protein which is a selective and potent inhibitor of coagulation Factor Xa. Previous studies indicated that an arginine residue located at position 34 of the inhibitor was cleaved by Factor Xa during the inhibition reaction. To evaluate this residue as the reactive site of antistasin, and to define shorter fragments of antistasin displaying Factor Xa-inhibitory activity, a series of peptides were synthesized corresponding to amino acids 27-49 of the inhibitor. The most potent peptide synthesized was a disulfide-bridged, 19 amino acid peptide, ATS29-47, which inhibited Factor Xa with a Ki = 35 nM, and increased plasma clotting times by over 4-fold at a concentration of 33 uM. Reduction or sulfation of the cysteine residues in ATS29-47 reduced Factor Xa inhibitory activity by over 95%. Peptides as short as seven residues corresponding to position 33-39 of antistasin displayed Factor Xa inhibitory activity. The peptides did not inhibit thrombin or trypsin at concentrations 1000-fold higher than used in Factor Xa assays. The shortest peptide displaying anticoagulant activity in human plasma was the disulfide-bridged peptide, D-Arg-Cys-Arg-Val-His-Cys-Pro, which increased clotting times by 50% at micromolar concentrations. These results demonstrate that antistasin-related peptide sequences can serve as model structures for the development of novel, low molecular weight anticoagulants.

Amino Acid Sequence↗
PubMed1994

[Study of peripheral neutrophil functions of patients with Wegener's granulomatosis].

Recently, the detection of anti-neutrophil cytoplasmic antibodies (ANCA) has gained worldwide acceptance as an important additional diagnostic tool of Wegener's granulomatosis (WG). A possible pathogenic role of ANCA has been suggested by the finding that the addition of purified IgG-ANCA to healthy neutrophils in vitro causes activation of these cells. But, investigation on neutrophil functions of patients with WG has been rare. To clarify this point, peripheral neutrophil functions (adherence, chemiluminescence and chemotaxis) of patients with active WG were examined. Adherence, chemiluminescence and chemotaxis of patients with WG were significantly suppressed when compared with control subjects. The effects of ANCA positive serum on neutrophil chemiluminescence were also examined. ANCA positive serum did not affect neutrophil chemiluminescence. These results indicate that the mechanism of WG is not simply due to neutrophil activation by ANCA.

Chemotaxis, Leukocyte↗
PubMed1994

[Clinical characterization of allergic patients sensitized to Chamaecyparis obtusa--using AlaSTAT system].

Clinical characterization of patients with allergy to Chamaecyparis obtusa (Cypress) pollen and their specific IgE antibody was investigated by using AlaSTAT assay, a new method for measurement of antigen-specific IgE antibody. Positive rate of antigen-specific antibody in patients with allergic pollinosis was 83.5% for Japanese cedar pollen and 80.0% for Chamaecyparis obtusa pollen. 76.4% of patients were sensitized both to Japanese cedar and Chamaecyparis obtusa pollen, however, 7.9% were sensitized only to the latter. As for clinical symptoms, duration of attack was short and severity was mild or moderate in the patients sensitized only to Chamaecyparis obtusa pollen. Patients who visited hospital in April, in that Chamaecyparis obtusa pollen disseminated in the air predominantly, showed significant elevation in AlaSTAT scores compared with patients who visited in February and March (p < 0.05).

Adolescent↗
PubMed1994

[Thiazide treatment for calcium urolithiasis in patients with idiopathic hypercalciuria].

The prophylactic effect of hydrochlorothiazide on stone formation was studied in 66 patients with calcium urolithiasis, (49 men and 17 women between 25 and 76 years old, mean 52.2 +/- 11.7 years) due to idiopathic hypercalciuria. Urinary calcium excretion was significantly decreased during treatment when compared to the baseline value. The stone formation rate was also significantly reduced when compared with that before treatment. With regard to side effects, hyperuricemia was observed in 21 patients, hypokalemia in 9 patients, hypotension in 3 patients, and glycosuria in 4 patients. Thiazide treatment was concluded to be effective for preventing the recurrence of calcium stones in patients with idiopathic hypercalciuria. However, this therapy should be used only in conjunction with the careful monitoring of possible adverse reactions.

Adult↗
PubMed1994

Diagnostic specificity of anti-neutrophil cytoplasmic antibodies (ANCA) in otorhinolaryngological diseases.

The incidence and titer of ANCA were examined with 871 sera from patients with otorhinolaryngological diseases at our hospital. The cytoplasmic pattern of ANCA (c-ANCA) whose titer was more than 16 was detected only in the sera of patients with Wegener's granulomatosis (WG). The incidence of c-ANCA in active WG was more than 90%. The perinuclear staining pattern of ANCA (p-ANCA) was detected in almost 40% of patients with Sjögren's syndrome, 2.0% of inflammatory diseases and 1.0% of tumorous diseases. A high diagnostic value of c-ANCA in WG was found in patients with otorhinolaryngological diseases.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1993

Internal mammary nodal status is a more reliable prognostic factor than DNA ploidy and c-erb B-2 expression in patients with breast cancer.

We evaluated the relationship among DNA ploidy, c-erb B-2 oncoprotein expression, and clinicopathologic prognostic factors, especially axillary and internal mammary node metastases, and their value in estimating the prognosis in 128 patients with operable breast cancer. There were significant correlations between DNA ploidy and clinical stage, tumor size, or axillary or internal mammary lymph node metastases, and between c-erb B-2 expression and clinical stage or axillary lymph node metastases. In a univariate study, overall or disease-free survival was significantly correlated to clinical stage, tumor size, DNA ploidy, c-erb B-2 expression, and axillary and internal mammary node metastases. In a multivariate study, however, only axillary and internal mammary node metastases were recognized as independent factors on overall survival, whereas on disease-free survival, only axillary lymph node metastases were identified as an independent indicator. Since the DNA ploidy status and c-erb B-2 expression were closely correlated with the axillary and/or internal mammary lymph node metastases, they did not appear as independent prognostic factors in this small series.

Adult↗