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Biomedical subjects

H Ikeda

Publications and source records attributed to H Ikeda.

At least 91 records · Page 5Linked to original sources
PubMed2002

Recombinant forms of glycophorin C as a tool for characterization of epitopes for new murine monoclonal antibodies with anti-glycophorin C specificity.

Glycophorin C (GPC) and glycophorin D (GPD) are minor but important components of human RBC membranes. They carry the high-frequency antigens Ge2, Ge3 and Ge4 of the Gerbich blood group system. The epitopes for five new monoclonal antibodies (MoAbs) with anti-GPC specificity were characterized. Two antibodies (4G11 and 5B11) reacted with glycosylated N-terminal epitopes, and three reacted with internal epitopes of GPC. Pepscan analysis showed that the MoAb RB11 required for binding the EPDP sequence, occurring twice in GPC polypeptide chain. The MoAb 7F11 recognized the sequence 13PLSLEPDP20, and the MoAb RB8 did not react with synthetic peptides. Further characterization of the internal epitopes was performed in fluorescence-activated cell sorter (FACS) with the use of recombinant GPC and its variant forms transiently expressed on COS-7 cells. The results indicated that the MoAb RB11 recognized distinctly its target sequence EPDP only in a normal GPC molecule. The reactivity of the MoAb 7F11 with the PLSLEPDP sequence was confirmed and found to be enhanced by the O-glycan at the Ser15 residue. The MoAb RB8 recognized the glycopeptidic epitope in proximity to the Ser15 residue, requiring the presence of O-glycan. The combination of immunochemical techniques with the use of the recombinant forms of GPC has made it possible to define the role of sugar chains in the recognition of peptidic epitopes in glycosylated antigen and sheds new light on the Gerbich system antigens.

Amino Acid Sequence↗
PubMed2002

Collagen-binding heat shock protein HSP47 expression during healing of fetal skin wounds.

Wounds in fetal animals are known to heal without scar formation, but the mechanism involved remains unclear. Scar tissue is characterized by disorganized collagen bundles. The 47-kDa heat shock protein (HSP47) is a molecular chaperone that specifically targets collagen processing. However, the role of HSP47 in scar formation is poorly understood. We studied the relation of HSP47 expression in skin to scar formation during fetal wound healing. Immunohistochemical analysis demonstrated HSP47-positive cells in the epidermal cell layer of fetal and neonatal rat skin and the absence of such cells in subcutaneous tissue. After induction of a wound on the back of fetal and neonatal rats, the message of collagen type I was increased only in neonatal skin but not in fetal skin. HSP47-positive cells consistently increased for 7 days after wound induction in neonatal rats. In contrast, HSP47-positive cells and HSP47 protein were unchanged in fetal rats. We conclude that the scarless healing of fetal skin wounds is related to lack of change in HSP47 expression. HSP47 may thus be an important determinant of scar formation during wound healing.

Animals↗
PubMed2002

Soluble forms of the selectin family in children with Kawasaki disease: prediction for coronary artery lesions.

AIM: To investigate the relationship between the plasma levels of soluble forms of the selectin family and the incidence of coronary artery lesions (CALs) in patients with Kawasaki disease (KD). METHODS: Thirty-three patients with KD, including group A patients (n = 22) who had no CALs and group B patients (n = 11) who had CALs, as well as age-matched febrile (n = 10) and afebrile controls (n = 11), were studied. RESULTS: Peak plasma E-selectin levels (172.0 +/- 58.6 ng ml(-1)) occurred during the acute phase of KD, while peak plasma P-selectin levels (260.3 +/- 43.2 ng ml(-1)) occurred during the subacute phase of the illness (p<0.05). Plasma L-selectin levels (1757.3 +/- 244.3 ng ml(-1)) during the convalescent phase tended to be higher than in either the acute or the subacute phase (not significant). Before intravenous immunoglobulin treatment, the plasma levels of E- (225.1 +/- 46.8 ng ml(-1)) and P-selectin (259.4 +/- 76.2 ng ml(-1)) of patients with CALs (n = 11) were significantly higher than those of patients (n = 22) with no CALs (E-selectin, 131.6 +/- 36.9 ng ml(-1); P-selectin, 184.9 +/- 84.6 ng ml(-1); p < 0.05). When a plasma E-selectin value before immunoglobulin treatment of >184.7 ng ml(-1) was used as the cut-off point, the sensitivity and specificity for the incidence of CALs were 81.8% and 90.9%, respectively. These findings demonstrate the relationship between plasma levels of selectins and disease severity of Kawasaki vasculitis. CONCLUSION: Higher plasma levels of E-selectin may have potential as a predictor of the incidence of coronary artery lesions in Kawasaki disease patients.

Child↗
PubMed2002

Ex vivo expansion of human UC blood primitive hematopoietic progenitors and transplantable stem cells using human primary BM stromal cells and human AB serum.

BACKGROUND: In vitro maintenance and expansion of human hematopoietic stem cells is crucial for many clinical applications, and investigators have been using xenogeneic, especially murine, stromal cells for stem-cell expansion. In addition, many such culture systems utilize FCS-containing medium or serum-free medium that contains human- or animal-derived proteins. However, the possible transmission of infectious diseases has led to a debate about the safety of the delivery of grafts expanded in culture using cells and proteins of allogeneic or xenogeneic origin. Using primary human BM stromal cells, we have established an AB serum-based co-culture system to expand human primitive progenitors and transplantable stem cells. METHODS: Cord blood CD34+ cells were cultured on a monolayer of human BM-derived primary stromal cells with thrombopoietin (TPO), stem-cell factor (SCF) and flt3/flk2 ligand (FL) in the presence of either FCS or AB serum. One to three weeks later, cells were examined for total cells, CD34+ cells, CD34+ CD38- cells, and clonogenic progenitors. SCID mouse reconstituting cell (SRC) activity was also studied. RESULTS: Three weeks of culture with TPO, SCF, and FL supported more than a 250-fold expansion of CD34+ cells, CD34+ CD38- cells and CFU-C, regardless of the kind of serum used. SRC assay revealed that transplantable stem cells were moderately expanded as well. DISCUSSION: This ex vivo expansion system should prove valuable in clinical settings in which stromal cells and serum are available from recipients or stem-cell donors.

ADP-ribosyl Cyclase↗
PubMed2002

[Therapeutic strategy for a patient suffering from a peripheral pulmonary tumor in the right upper lobe and an endotracheal tumor in the carina].

A 64-year-old male, who had received successful radiotherapy for the previous laryngeal cancer, was admitted to our department for the treatment of a peripheral pulmonary tumor in the right upper lobe and an endotracheal tumor in the carina. The endotracheal biopsy of the carinal tumor demonstrated squamous cell carcinoma, though preoperative examination of the intrapulmonary tumor was unable to clarify it's pathological type. The intrapulmonary tumor required right upper lobectomy and R2 lymph node dissection as a measure against the possibility of primary lung cancer. Since the endotracheal cancer was diagnosed as an intra mucosal tumor by the preoperative computed tomography (CT) scans and the bronchoscopic examination, laser abrasion therapy to the endotracheal tumor was performed 4 days before the lobectomy of the intrapulmonary tumor. After the pulmonary operation, the intrapulmonary tumor was diagnosed as squamous cell carcinoma without lymph node metastasis, and it was suggested to be a metastatic tumor of the previous laryngeal cancer. Both radiotherapy to the carina and general chemotherapy with docetaxel hydrate and carboplatin were used as adjuvant therapies 36 days after the lobectomy. One year after the pulmonary surgery, there is no recurrence of the tumor in the lung or carina. Laser abrasion therapy to the endotracheal tumor is very useful and safe for the patient, who should then receive pulmonary resection soon after the therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

[Clinical study of eight thymic carcinomas].

Eight patients with thymic carcinoma were surgically treated at Sapporo City General Hospital from September 1990 to January 2002. The histological subtypes of thymic carcinoma were squamous cell in 5, undifferentiated in 2, and small cell in one. After median sternotomy, 5 patients had total resection of the tumor, and 3 had incomplete resection due to extensive mediastinal invasion involving the main pulmonary artery in the A-P window. Of 3 cases with intra pericardial malignant effusion, one patient survived 7 years without recurrence of the tumor after the exploratory operation followed by mediastinal irradiation without chemotherapy. In this patient, existence of the malignant cells in the pericardial effusion was not associated with poor outcome.

Adult↗
PubMed2001

Observation of the decay B --> Kl+l-.

We report a search for the flavor-changing neutral current decay B-->K(*)l+l- using a 29.1 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- storage ring. We observe the decay process B-->Kl+l-(l = e, mu), for the first time, with a branching fraction of B(B-->Kl+l-) = (0.75(+0.25)(-0.21)+/-0.09)x10(-6).

Journal Article↗
PubMed2001

Phagocytosis in vitro of polyethylene glycol-modified liposome-encapsulated hemoglobin by human peripheral blood monocytes plus macrophages through scavenger receptors.

Liposome-encapsulated hemoglobin (LEH), a candidate for red blood cell substitute, is cleared from circulation primarily by the phagocytic system, most likely after opsonization of the vesicles by immunoproteins, particularly complement components. Although modification of LEH by polyethylene glycol (PEG) derivatives prolongs its half-life by blocking the opsonization, the half-life is still short as compared with that of red blood cell components. Therefore, this study was performed to elucidate the opsonin-independent mechanisms that regulate phagocytosis of Neo Red Cell (NRC), a PEG-modified LEH, in culture. PKH67 was used as a fluorescence marker, allowing the quantitation of the phagocytosis of NRC by peripheral blood monocytes plus macrophages. The phagocytosis of PKH67-labeled NRC was inhibited by the addition of an excess of unlabeled NRC, indicating that the phagocytosis of PKH67-labeled NRC is specific to NRC, but not to PKH67. The phagocytosis of NRC was blocked about 70% by anti-CD14, 60% by anti-CD36 and 30% by anti-CD51/61 (vitronectin receptor, alpha(v)beta3). These results provided evidence of an opsonin-independent pathway for the phagocytosis of PEG-modified LEH.

Antigens, CD↗
PubMed2001

Localized aggressive non-Hodgkin's lymphoma of the nasal cavity: a survey by the Japan Lymphoma Radiation Therapy Group.

PURPOSE: To clarify the role of radiotherapy and chemotherapy in the treatment of patients with localized aggressive non-Hodgkin's lymphomas (NHL) originating in the nasal cavity. METHODS AND MATERIALS: The survey, administered at 25 Japanese institutes in 1998, enabled us to collect the clinical data for 787 patients with localized aggressive NHL who were treated between 1988 and 1992. RESULTS: There were 42 patients (5%) with nasal lymphomas. Twelve of these patients received radiotherapy alone, and 30 were treated with a combination of radiotherapy and chemotherapy. The median radiation dose was 47 Gy (22-66). Twelve patients were reviewed histopathologically according to REAL (Revised European-American Classification of Lymphoid neoplasms) classification. T-cell or natural killer (NK) cell lymphomas were detected in 9 patients (75%), and diffuse large B-cell lymphomas in 3 (25%). The 5-year overall and disease-free survival (DFS) rates of all patients were 57% and 59%, respectively. The 5-year DFS rate for the 30 patients treated with the combined therapy was 64% and that for the 12 patients treated with radiotherapy alone was 46% (p = 0.021). For the 34 patients with stage-modified International Prognostic Index (m-IPI) 0-1, the 5-year DFS rates of those treated with the combined therapy and radiotherapy alone were 68% and 45%, respectively (p = 0.020), but there was no difference in DFS rate among the two groups of patients with m-IPI 2-3. The 5-year local control rates of the patients who received >46 Gy (n = 22) and < or =46 Gy (n = 20) were 95% and 76% (p = 0.087), respectively. There was no significant difference among the 5-year DFS rates (62% vs. 67%) and local control rates (87% vs. 100%) of the patients with T-cell or NK-cell lymphoma and diffuse large B-cell lymphoma. CONCLUSIONS: Patients with nasal lymphomas (m-IPI 0-1) should be treated with combined therapy. For the patients with high risk (m-IPI 2-3), the effectiveness of combined therapy was not clarified because of the small number of the patients. A high radiation dose >46 Gy may need to be used to achieve good local control.

Adolescent↗
PubMed2001

Role of SEREX-defined immunogenic wild-type cellular molecules in the development of tumor-specific immunity.

Recognition of altered self-antigens in tumor cells by lymphocytes forms the basis for antitumor immune responses. The effector cells in most experimental tumor systems are CD8(+) T cells that recognize MHC class I binding peptides derived from molecules with altered expression in tumor cells. Although the need for CD4(+) helper T cells in regulating CD8(+) T cells has been documented, their target epitopes and functional impact in antitumor responses remain unclear. We examined whether broadly expressed wild-type molecules in murine tumor cells eliciting humoral immunity contributed to the generation of CD8(+) T cells and protective antitumor immune responses to unrelated tumor-specific antigens [mutated ERK2 (mERK2) and c-erbB2/HER/neu (HER2)]. The immunogenic wild-type molecules, presumably dependent on recognition by CD4(+) helper T cells, were defined by serological analysis of recombinant cDNA expression libraries (SEREX) using tumor-derived lambda phage libraries screened with IgG antibodies of hosts bearing transplanted 3-methylchoranthrene-induced tumors. Coimmunization of mice with plasmids encoding SEREX-defined murine wild-type molecules and mERK2 or HER2 led to a profound increase in CD8(+) T cells specific for mERK2 or HER2 peptides. This heightened response depended on CD4(+) T cells and copresentation of SEREX-defined molecules and CD8(+) T cell epitopes. In tumor protection assays, immunization with SEREX-defined wild-type molecules and mERK2 resulted in an inhibition of pulmonary metastasis, which was not achieved by immunization with mERK2 alone.

Animals↗
PubMed2001

Intraplatelet tetrahydrobiopterin plays an important role in regulating canine coronary arterial thrombosis by modulating intraplatelet nitric oxide and superoxide generation.

BACKGROUND: Platelet-derived nitric oxide inhibits platelet aggregation via constitutive NO synthase (NOS). Tetrahydrobiopterin (BH(4)), a cofactor of NOS, augments NO formation, whereas its deficiency decreases NO bioactivity and increases superoxide generation by NOS. The roles of intraplatelet BH(4) in platelet aggregation and thrombus formation, however, are unknown. Accordingly, we investigated whether intraplatelet BH(4) is involved in regulating cyclic flow variations (CFVs) and platelet aggregation in a canine model with stenosed and endothelium-injured coronary arteries that mimics acute coronary syndromes in humans. METHODS AND RESULTS: After developing CFVs, dogs received saline or BH(4) (10 or 30 mg/kg) intravenously. Intraplatelet BH(4) and cGMP levels were decreased and intraplatelet nitrotyrosine production was increased during CFVs. ADP- and U46619-induced ex vivo platelet aggregation and platelet P-selectin expression were augmented during CFVs. BH(4) administration restored intraplatelet BH(4) and cGMP levels and decreased intraplatelet nitrotyrosine production, resulting in reduced CFVs and inhibited ex vivo platelet aggregation and platelet P-selectin expression. CFVs again developed after N(G)-monomethyl-L-arginine, an inhibitor of NOS, in BH(4)-treated dogs. Ex vivo platelet NOS activity at baseline, during CFVs, and after BH(4) administration did not differ. CONCLUSIONS: Intraplatelet BH(4) may play an important role in regulating thrombus formation by modulating platelet-derived nitric oxide and superoxide generation by platelet NOS.

Animals↗
PubMed2001

Augmented oxidative stress of platelets in chronic smokers. Mechanisms of impaired platelet-derived nitric oxide bioactivity and augmented platelet aggregability.

OBJECTIVES: We investigated whether impaired platelet-derived nitric oxide (PDNO) bioactivity and augmented platelet aggregability in chronic smokers are related to the imbalance of the intraplatelet redox state through increased oxidative stress. BACKGROUND: Chronic smoking impairs PDNO release and augments platelet aggregability. However, their mechanisms are unknown. METHODS: Collagen-induced PDNO release, platelet aggregation, plasma and intraplatelet vitamin C and reduced glutathione (GSH), intraplatelet cyclic guanosine 3',5'-monophosphate (cGMP) and intraplatelet nitrotyrosine production, which is a marker of the peroxynitrite formation, were measured in 11 chronic smokers and 10 age-matched nonsmokers. RESULTS: Release of PDNO and levels of intraplatelet cGMP were lower, and platelet aggregation was greater, in smokers than in nonsmokers. Intraplatelet vitamin C and GSH levels were lower in smokers than in nonsmokers. Intraplatelet nitrotyrosine production was greater in smokers than in nonsmokers. Next, we investigated the effects of oral vitamin C administration (2 g). After vitamin C administration, intraplatelet vitamin C levels were increased and not different at 2 h between the two groups. Then, PDNO release, intraplatelet cGMP levels and platelet aggregation in smokers were restored to the levels of nonsmokers. In smokers, PDNO release and consumption of GSH during platelet aggregation were inversely correlated, and consumption was much less after vitamin C administration. Vitamin C administration decreased intraplatelet nitrotyrosine production in smokers. CONCLUSIONS: Impaired PDNO bioactivity and augmented platelet aggregability may be caused by an imbalance of the intraplatelet redox state through increased oxidative stress in smokers.

Administration, Oral↗
PubMed2001

Structural features of aliphatic N-nitrosamines of 7-azabicyclo[2.2.1]heptanes that facilitate N-NO bond cleavage.

N-Nitrosamines can be considered as potential nitric oxide (NO)/nitrosonium ion (NO(+)) donors. However, the relation of the structures of N-nitrosamines, in particular of aliphatic N-nitrosamines, to the characteristics of release of NO or NO(+) remains unclear. Here we show that aliphatic N-nitrosoamines of 7-azabicyclo[2.2.1]heptanes can undergo heterolytic N-NO bond cleavage. On the basis of the observation of reduced rotational barriers of the N-NO bonds in solution and nitrogen-pyramidal structures of the N-nitroso group in the solid state, we postulate that N-NO bond cleavage of N-nitrosamines is enhanced by a reduction of the resonance in the N-NO group. Computational studies suggest that these structural features of the N-nitrosamines of 7-azabicyclo[2.2.1]heptane are derived from angle strain imposed on the CNC angles.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed2001

Observation of B --> J/psi K(1)(1270).

We report the first observation of the exclusive decay process B-->J/psi K(1)(1270) using a sample of 11.2M BB macro meson pairs collected in the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. We measure branching fractions of B[B(0)-->J/psi K(0)(1)(1270)] = (1.30+/-0.34+/-0.32) x 10(-3) and B[B(+)-->J/psi K(+)(1)(1270)] = (1.80+/-0.34+/-0.39) x 10(-3), where the first error is statistical and the second is systematic. These modes constitute approximately 15% of the total number of B-->J/psi X decays. No evidence is seen for B-->J/psi K(1)(1400) and we set an upper limit for this branching fraction.

Journal Article↗
PubMed2001

Genome sequence of an industrial microorganism Streptomyces avermitilis: deducing the ability of producing secondary metabolites.

Streptomyces avermitilis is a soil bacterium that carries out not only a complex morphological differentiation but also the production of secondary metabolites, one of which, avermectin, is commercially important in human and veterinary medicine. The major interest in this genus Streptomyces is the diversity of its production of secondary metabolites as an industrial microorganism. A major factor in its prominence as a producer of the variety of secondary metabolites is its possession of several metabolic pathways for biosynthesis. Here we report sequence analysis of S. avermitilis, covering 99% of its genome. At least 8.7 million base pairs exist in the linear chromosome; this is the largest bacterial genome sequence, and it provides insights into the intrinsic diversity of the production of the secondary metabolites of Streptomyces. Twenty-five kinds of secondary metabolite gene clusters were found in the genome of S. avermitilis. Four of them are concerned with the biosyntheses of melanin pigments, in which two clusters encode tyrosinase and its cofactor, another two encode an ochronotic pigment derived from homogentiginic acid, and another polyketide-derived melanin. The gene clusters for carotenoid and siderophore biosyntheses are composed of seven and five genes, respectively. There are eight kinds of gene clusters for type-I polyketide compound biosyntheses, and two clusters are involved in the biosyntheses of type-II polyketide-derived compounds. Furthermore, a polyketide synthase that resembles phloroglucinol synthase was detected. Eight clusters are involved in the biosyntheses of peptide compounds that are synthesized by nonribosomal peptide synthetases. These secondary metabolite clusters are widely located in the genome but half of them are near both ends of the genome. The total length of these clusters occupies about 6.4% of the genome.

Base Sequence↗
PubMed2001

Comparison of SSR and QSART in early diabetic neuropathy--the value of length-dependent pattern in QSART.

We evaluated postganglionic sympathetic function using the sympathetic skin response (SSR) and quantitative sudomotor axon reflex test (QSART) on the feet of 31 patients with early diabetic neuropathy and 20 age-matched normal controls. The amplitude of SSR and the sweat volume of QSART were significantly decreased in the diabetic patients. We evaluated the sensitivity of the tests in detecting autonomic failure. Out of 31 patients, 14 (45%) had abnormal SSR (14 absent; 17 present), while 16 of 31 patients (52%) had abnormal QSART (1 absent; 5 absolutely reduced and 10 showed a length-dependent pattern of reduction). More important than differences in sensitivity is the specificity of QSART, which specifically evaluates the postganglionic axon (instead of polysynaptic pathways in SSR) and provides quantitative data on the severity and pattern of autonomic deficit. In normal controls under 65 years of age, there was a significant correlation between the amplitude of SSR and the sweat volume of QSART. However, there was no significant relationship between these in diabetic patients. These results suggest that QSART can evaluate early diabetic neuropathy more precisely than SSR.

Aged↗
PubMed2001

Liposome-encapsulated superoxide dismutase suppresses liposome-mediated augmentation of TNF-alpha production from peripheral blood leucocytes.

Liposome-encapsulated hemoglobin (LEH), a candidate for a red cell substitute, has been reported to be cleared from circulation primarily by the phagocytic system and modulate the production of inflammatory cytokines, such as TNF-alpha and IL-6, both in vivo and in vitro. In this study, we investigated the effects of liposome vesicles on the LPS-induced TNF-alpha production using a whole blood culture system. We also studied the effects of superoxide dismutase (SOD) encapsulated in liposome on the cytokine production. The pre-treatment of whole blood with liposome vesicles potentiated the LPS-induced TNF-alpha production. The encapsulation of SOD in the liposome vesicles suppressed the liposome-mediated augmentation of TNF-alpha production in a dose-dependent manner. These results suggest that encapsulation of SOD in LEH decreases the production of inflammatory cytokines from the phagocytic system which may be caused or augmented by LEH infusion in vivo.

Drug Carriers↗