Biomedical subjects

Y Ebihara

Publications and source records attributed to Y Ebihara.

At least 19 recordsLinked to original sources

PubMed2001

Generation of definitive hematopoietic stem cells from murine early yolk sac and paraaortic splanchnopleures by aorta-gonad-mesonephros region-derived stromal cells.

There is controversy as to whether murine definitive hematopoiesis originates from yolk sac (YS) or the intraembryonic region. This study reports the generation of definitive hematopoietic stem cells (HSCs) from both early YS and intraembryonic paraaortic splanchnopleures (P-Sp) on AGM-S3 stromal cells derived from the aorta-gonad-mesonephros (AGM) region at 10.5 days post coitum (dpc). YS and P-Sp cells at 8.5 dpc generated no definitive hematopoiesis-derived colony-forming cells in cocultures with AGM-S3 cells, but spleen colony-forming cells and HSCs capable of reconstituting definitive hematopoiesis in adult mice simultaneously appeared on day 4 of coculture. Precursors for definitive HSCs were present in YS and P-Sp at 8.0 dpc, a time when YS and embryo were not connected by blood vessels. It is proposed that precursors with the potential to generate definitive HSCs appear independently in YS and intraembryonic P-Sp and that the P-Sp or AGM region affords the microenvironment that facilitates generation of definitive hematopoiesis from precursors.

Animals↗

PubMed2001

Development of human lymphohematopoietic stem and progenitor cells defined by expression of CD34 and CD81.

In this study, cord blood CD34(+) cells expressed CD81, a member of the transmembrane 4 superfamily, and were classified into 3 subpopulations on the basis of their expression levels: CD34(+)CD81(+), CD34(low)CD81(+), and CD34(+)CD81(high). The lymphohematopoietic activity of each subpopulation was then examined by using suspension and clonogenic cultures for hematopoietic potential, coculture with MS-5 cells for B-cell potential, organ cultures of thymus lobes from nonobese diabetic/severe combined immunodeficiency disease (NOD/SCID) fetal mice, coculture with stromal cells derived from NOD/SCID fetal-mouse liver tissue for natural killer (NK) cell and mast cell potentials, and xenotransplantation into NOD/SCID mice for long-term repopulating (LTR) ability. CD34(+)CD81(+) cells represented a heterogeneous population that had all the lymphohematopoietic activities, including NOD/SCID mouse-repopulating ability. CD34(low)CD81(+) cells were enriched in erythroid, megakaryocytic, and NK lineage potentials but had lost T-cell and B-cell potentials and LTR ability. The CD34(+)CD81(high) fraction was depleted of most lymphohematopoietic potentials except NK cell and mast cell potentials. Thus, along the differentiation cascade from CD34(+)CD81(+) lymphohematopoietic stem cells, an up-regulation of CD81 or a down-regulation of CD34 results in a change in lymphohematopoietic properties. CD81 may serve as a marker for defining developmental stages of lymphohematopoietic stem cells. (Blood. 2001;97:3755-3762)

Animals↗

PubMed2001

Shared antigenicity between Helicobacter pylori and periodontopathic Campylobacter rectus strains.

Periodontopathic Campylobacter rectus strains possess 41- and 68-kDa proteinaceous antigens which share antigenicity with antigens of Helicobacter pylori strains. H. pylori strains have a 54-kDa antigen which reacts with C. rectus strains. We found that the salivary IgA levels against H. pylori were correlated with those against C. rectus. These cross-reactive antigens of C. rectus may affect the serological diagnosis of H. pylori infections, especially when saliva is used. It is possible that these cross-reacting antigens may relate to the induction of immunopathological responses against both microorganisms.

Antigens, Bacterial↗

PubMed2001

Evidence for the presence of murine primitive megakaryocytopoiesis in the early yolk sac.

During mouse embryogenesis, primitive erythropoiesis occurs in blood islands of the yolk sac (YS) on the seventh day of gestation. This study demonstrated for the first time the presence of unique primitive megakaryocytic (Mk) progenitors in the early YS, which disappeared by 13.5 days postcoitum (dpc). When 7.5 dpc YS cells were incubated in the presence of stem cell factor (SCF), interleukin (IL)-3, IL-6, erythropoietin (EPO), thrombopoietin (TPO), and granulocyte colony-stimulating factor in methylcellulose clonal culture, not only erythroid bursts but also megakaryocyte colonies were observed. The megakaryocytes in the colonies matured to proplatelet stages and produced platelets as early as day 3 of culture, much earlier than those from adult bone marrow, although their ploidy class was lower. These megakaryocytes were stained with acetylcholine esterase, and expressed platelet glycoprotein (GP)Ib beta, GPIIIa, and platelet factor 4 by reverse transcription-polymerase chain reaction analysis. The analysis of hemoglobin types in erythrocytes obtained from hematopoietic multilineage colonies containing the megakaryocytes indicated that the Mk progenitors originated from primitive hematopoiesis. The primitive Mk progenitors formed colonies in the absence of any cytokines in fetal bovine serum (FBS)-containing culture, and SCF, IL-3, EPO, and TPO significantly enhanced the Mk colony formation. In FBS-free culture, however, no colony formation was induced without these cytokines. Because megakaryocytes were detected in 8.5-dpc YS, these unique primitive Mk progenitors may rapidly mature and give rise to platelets to prevent hemorrhage in the simultaneously developing blood vessels until definitive hematopoiesis begins to produce platelets. (Blood. 2001;97:2016-2022)

Animals↗

PubMed2001

CD34 expression on long-term repopulating hematopoietic stem cells changes during developmental stages.

The CD34 antigen serves as an important marker for primitive hematopoietic cells in therapeutic transplantation of hematopoietic stem cells (HSC) and gene therapy, but it has remained an open question as to whether or not most HSC express CD34. Using a competitive long-term reconstitution assay, the results of this study confirm developmental changes in CD34 expression on murine HSC. In fetuses and neonates, CD34 was expressed on Lin(-)c-Kit(+) long-term repopulating HSC of bone marrow (BM), liver, and spleen. However, CD34 expression on HSC decreased with aging, and in mice older than 10 weeks, HSC were most enriched in the Lin(-)c-Kit(+)CD34(-) marrow cell fraction. A second transplantation was performed from primary recipients who were transplanted with neonatal Lin(-)c-Kit(+) CD34(high) HSC marrow. Although donor-type HSC resided in CD34-expressing cell fraction in BM cells of the first recipients 4 weeks after the first transplantation, the stem cell activity had shifted to Lin(-)c-Kit(+)CD34(-) cells after 16 weeks, indicating that adult Lin(-)c-Kit(+)CD34(-) HSC are the progeny of neonatal CD34-expresssing HSC. Assays for colony-forming cells showed that hematopoietic progenitor cells, unlike HSC, continue to express CD34 throughout murine development. The present findings are important because the clinical application of HSC can be extended, in particular as related to CD34-enriched HSC and umbilical cord blood HSC.

Age Factors↗

PubMed2001

In situ telomerase activity in pleural effusions: a promising marker for malignancy.

Telomerase activity in 16 pleural effusions was studied using an in situ telomerase repeat amplification protocol (TRAP) assay on cytospin preparations. Six of nine cytologically malignant specimens contained telomerase-positive cells (67%), and in two further specimens, suspicious positive cells were seen. Two of four atypical specimens contained telomerase-positive cells, whereas two benign cases were telomerase-negative. No mesothelial cells showed telomerase reactivity. Thus, telomerase activity was specific for malignancy and it was always found only in malignant cells. The results suggest that telomerase activity measured with this in situ method can be a valuable complement in the assessment of malignancy in pleural effusions.

Biomarkers, Tumor↗

PubMed2001

Prompt and durable hematopoietic reconstitution by unrelated cord blood transplantation in a child with Fanconi anemia.

We describe here the case of an 8-year-old girl with Fanconi anemia (FA) whose hematopoiesis was successfully restored by unrelated umbilical cord blood (UCB) transplantation. The patient became resistant to androgen therapy, and developed intracranial hemorrhage and dyserythropoiesis. Her hematopoietic recovery after the transplantation was excellent and a complete chimerism has been durably maintained. UCB should be considered as a stem cell source for transplantation when a patient with FA does not have an HLA-identical unaffected sibling donor.

Child, Preschool↗

PubMed2001

Interrelationship between Epstein-Barr virus infection in gastric carcinomas and the expression of apoptosis-associated proteins.

AIMS: Epstein-Barr virus (EBV) and its associated proteins may be protective against the occurrence of apoptosis that would normally inhibit cancer development and progression. Alternatively, the viral infection may cause altered or mutated expression of oncogenes or tumour suppressor genes that are necessary for tumour development, an action that may also involve apoptosis. In this study, a relationship was sought between occurrence of EBV infection, expression of apoptosis-associated proteins (tumour suppressor gene p53 and oncogenes c-myc and bcl-2) and levels of cell death (apoptosis or necrosis) in 119 cases of gastric carcinoma. METHODS AND RESULTS: The EBV status of the gastric carcinomas (using the EBV-encoded small RNA I (EBER-1) and in-situ hybridization), stage and grade of tumour and sex of patients were compared for bcl-2, p53 and c-myc expression patterns. EBER-1 was detected in approximately 20% of cases studied. There was no significant correlation between levels of cell death in the tumour tissue and EBV status. In the protein analyses, development and progression of gastric carcinoma, with or without EBV infection, was independent of bcl-2 expression. However, in gastric cancers with EBV infection, p53 overexpression was inhibited and c-myc expression was increased in early stage cancers, in comparison with decreased c-myc expression in late stage cancers. CONCLUSIONS: The p53 and c-myc expression patterns indicate that EBV-infected gastric carcinomas are less likely to have a natural regression via apoptosis at an early stage and explain, in part, the resistance to treatment of late stage of gastric cancers.

Adenocarcinoma↗

PubMed2001

Serum insulin-like growth factor-1 in centenarians: implications of IGF-1 as a rapid turnover protein.

BACKGROUND: It is well documented that serum insulin-like growth factor 1 (IGF-1) levels as well as growth hormone secretion decline with advancing age. Low levels of IGF-1 are shown to be associated with low activity of growth hormone, low lean mass, and high body fat mass; however, in the elderly, the relationship has not been confirmed. METHODS: We studied serum IGF-1 levels in 49 centenarians, who are at the ultimate stage of physiological senescence, and investigated the possible relationship between IGF-1 and body mass index, lipid parameters, nutritional indices, physical and cognitive function, and frequency of hip fracture. As nutritional indices, serum levels of albumin, prealbumin, transferrin, and retinol binding protein were measured. Cognitive function of the centenarians was assessed by clinical dementia rating. RESULTS: In the centenarians, the mean levels of IGF-1 were relatively low, indicating that there is an age-associated decline in IGF-1 even in the extremely old age. We demonstrated a strong association of IGF-1 with prealbumin and retinol binding protein (r2 = .192, .195, respectively); however, there was no association with albumin, transferrin, or body mass index. Interestingly, centenarians with lower IGF-1 levels had a higher prevalence of definitive dementia. CONCLUSIONS: These data suggest that serum IGF-1 levels in the centenarians appeared to reflect their short-term nutritional status as a rapid turnover protein. It is also suggested that low levels of serum IGF-1 may be involved in the progression of dementia in the oldest old.

Aged↗

PubMed2001

MALT lymphoma originating in breast and uvula.

A case of marginal zone B cell lymphoma of MALT type arising in the uvula and breast is reported. The patient, a 30-year-old woman who delivered a child and lactated in 1997, was suffering from Sjögren syndrome (SS). She was diagnosed with MALT lymphoma after a biopsy of the right breast and uvula. To investigate the relationship of the delivery, lactation and MALT lymphoma, we examined the immunohistochemical analysis of hormone receptors. As a result, lymphoid cells of the breast were stained with anti-progesterone receptor antibodies in the cytoplasm. Consequently, the MALT lymphoma of the uvula appeared to be associated with SS. Moreover, hormones such as progesterone may have influenced the breast involvement of MALT lymphoma in our case.

Adult↗

PubMed2001

[Suggestions from a centenarian study--aging and inflammation].

With the numbers of elderly increasing rapidly, it is important for both individuals and society that the oldest old maintains autonomy. To know how to attain successful aging, we investigate the status of centenarians. The characteristics of centenarians in Tokyo is 1) low level of nutritional parameters, 2) low level of cholesterol and HDL-cholesterol, 3) low level of red blood cells and hemoglobin, 4) high level of CRP, 5) high level of homocysteine, 6) high level of von Willbrand factor. The incidence of dementia is 59.3%. Are these characteristics due to aging itself or other factors? We examined the effect of nutritional status, inflammation and level of homocysteine on the characteristics. The level of albumin is associated with serum level of lipid, RBC, ADL and cognitive function. The level of CRP is related to the level of albumin, suggesting that inflammation is related to nutritional status. The level of homocysteine is associated with the level of von Willbrand factor, suggesting that homocysteine is related to endothelial injury. From these data, we propose the hypothesis that proinflammatory status is associated with aging, resulting in a part of characteristics of centenarians. Homocysteine is partly responsible for endothelial injury. Intervention to suppress proinflammatory status and homocysteine level may promote QOL in the oldest old.

Aged↗

PubMed2001

K-ras mutation in sputum of primary lung cancer patients does not always reflect that of cancerous cells.

K-ras mutation in sputum was examined using mutant-allele-specific amplification method among 100 primary lung cancer and 15 non-oncological patients. K-ras mutation was detected in 11 out of 59 adenocarcinoma cases (18.6%), 5 out of 32 squamous cell carcinoma cases (15.6%), 2 out of 4 large cell carcinoma cases (50.0%) and 3 out of 15 non-oncological disease cases (20.0%). In the 18 cases of primary lung cancer K-ras mutation was examined in both sputum and the resected specimen of the primary lesion. In 5 cases K-ras mutation in sputum was detected without K-ras mutation in primary lesion. Therefore, these findings suggested that K-ras mutation in sputum may not be directly related to that of the primary lesion.

Adult↗

PubMed2001

Surfactant protein D and KL-6 as serologic indicators of Pneumocystis carinii pneumonia in a child with acute lymphoblastic leukemia.

Pneumocystis carinii pneumonia (PCP) in immunocompromised patients is one of the important causes of morbidity and mortality. Serum levels of surfactant protein D (SP-D) and KL-6 are useful biomarkers for understanding some pulmonary inflammatory responses in patients with idiopathic pulmonary fibrosis (IPF). We present a child with PCP following bone marrow transplantation (BMT) for acute lymphoblastic leukemia (ALL), for whom both SP-D and KL-6 in sera were simultaneously measured through the clinical course of PCP. Both serum levels of SP-D and KL-6 were rapidly elevated reflecting some inflammatory processes in the lung that chest X-ray films and CT scans showed as ground-glass attenuations. He died due to respiratory failure 40 days after PCP developed. A combination of the assays for SP-D and KL-6 in sera may be helpful in predicting the treatment results for PCP.

Adolescent↗

PubMed2001

[CD56- and CD4-positive non-Hodgkin's lymphoma of probable T-cell origin].

A 65-year-old man was admitted with swelling of the right neck and bilateral inguinal lymph nodes. Endoscopic examination revealed no nasal infiltration. Pathological examination of a neck lymph node biopsy specimen revealed peripheral T-cell lymphoma according to the Revised European-American Classification of Lymphoid Neoplasms (REAL). The phenotype of the lymphoma cells was CD56+, CD16-, CD2+, surface CD3-, cytoplasmic CD3+, CD4+, CD8-, CD5+, CD7- and CD45RO+. May-Giemsa staining demonstrated no azurophilic granules in the lymphoma cells. Immunohistopathologic examination showed negativity for TIA-1 and granzyme B, and rearrangement of the TCR C beta 1 gene was also noted. These findings strongly suggested that this was a T-cell lymphoma. The patient received 8 courses of CHOP chemotherapy plus sobuzoxane. This led to a marked decrease of lymph node swelling, and currently the patient is still in remission. According to the REAL classification, T/NK-cell lymphomas are included among the peripheral T cell tumours, and seem to constitute a heterogeneous group of neoplasms. Although some cases of CD4+ CD56+ lymphoma have been reported, the present case appears to be the first example to show TCR gene rearrangement and negativity for TIA-1 and granzyme B. Since the classification of T/NK-cell lymphoma is still controversial, accumulation of such cases may help to better define T/NK-cell neoplasms.

Aged↗

PubMed2000

Correlation between morphology and telomerase activity in cells from exfoliative lung cytologic specimens.

BACKGROUND: Telomerase is a ribonucleoprotein that compensates for the erosion of telomeres (chromosomal termini). Telomerase activity is detected in more than 85% of cancerous lesions and is therefore considered a novel marker of cancer. The authors compared cytologic morphology and telomerase activity at the cellular level to obtain further insight into their association. METHODS: The authors used bronchial washing and brushing materials obtained from 18 patients with lung carcinomas (6 squamous cell, 8 adenocarcinoma, 2 large cell, 1 small cell, and 1 metastasis from colon carcinoma) and 20 patients with nonmalignant disease. An in situ telomeric repeat amplification protocol (TRAP) assay was performed, and routine Papanicolaou-stained slides using the same sample were assessed. RESULTS: Nuclear fluorescent signals at the nuclear area, corresponding to telomerase activity, shown by the in situ TRAP assay were only detected in samples containing morphologically malignant cells. No nuclear fluorescence was seen in the keratinizing component of well-differentiated squamous cell carcinoma. Nuclear staining was not seen in metaplastic or basal hyperplastic cells. Cytoplasmic fluorescence was only found in macrophages and polymorphonuclear leukocytes. CONCLUSIONS: Nuclear fluorescence corresponding to telomerase activity was not demonstrated in metaplastic or basal hyperplastic cells, thus indicating that detection of telomerase activity is closely associated with the presence of malignant cells, but not premalignant lesions, in lung carcinoma patients. Moreover, in some samples with cancer, cells failed to show telomerase activity, suggesting the limitation of this method for the detection of malignant cells in certain lung carcinoma patients.

Adenocarcinoma↗

PubMed2000

Nuclear cyclin D1 overexpression is a critical event associated with cell proliferation and invasive growth in gallbladder carcinogenesis.

Cyclin D1 overexpression is remarkably frequent in several human carcinomas and is believed to be a critical event in oncogenesis. We examined cyclin D1 expression, p53 expression, and the Ki-67 labeling index by immunostaining in human gallbladder mucosa in conditions varying from normal to malignant tissue. We also examined K-ras codon 12 mutations in these tissues with a two-step polymerase chain reaction. Nuclear cyclin D1 overexpression was observed in 48% of carcinomas occurring independently of adenoma, but not in adenomas, carcinomas arising in adenomas, or nonneoplastic lesions. Cytoplasmic cyclin D1 overexpression was observed in about 15% of abnormal specimens, irrespective of the type of epithelial abnormality. Carcinomas showing nuclear cyclin D1 overexpression had significantly higher Ki-67 labeling indexes than those with no overexpression. Moderately to poorly differentiated adenocarcinomas showed a higher incidence of nuclear cyclin D1 overexpression than papillary to well differentiated carcinomas. Specimens with cyclin D1 overexpression showed a high incidence of lymph permeation, venous permeation, and lymph node metastasis. We conclude that nuclear cyclin D1 overexpression is a critical event importantly associated with cell proliferation and invasive growth in gallbladder carcinogenesis, and that cyclin D1 immunostaining may become a useful marker for evaluating gallbladder carcinomas.

Adenocarcinoma↗

PubMed2000

Control of B cell production by the adaptor protein lnk. Definition Of a conserved family of signal-modulating proteins.

Lnk is an SH2 domain-containing adaptor protein expressed preferentially in lymphocytes. To illuminate the importance of Lnk, we generated lnk(-/-) mice. Whereas T cell development was unaffected, pre-B and immature B cells accumulated in the spleens. In the bone marrow, B-lineage cells were proportionately increased, reflecting enhanced production of pro-B cells that resulted in part from hypersensitivity of precursors to SCF, the ligand for c-kit. Hence, Lnk ordinarily acts to regulate B cell production. Further characterization of lnk(-/-) mice also revealed that full-length Lnk is a 68 kDa protein containing a conserved proline-rich region and a PH domain. Lnk is a representative of a multigene adaptor protein family whose members act, by analogy with Lnk, to modulate intracellular signaling.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Improvement in bronchiolitis obliterans organizing pneumonia in a child after allogeneic bone marrow transplantation by a combination of oral prednisolone and low dose erythromycin.

We report a 13-year-old boy who developed dyspnea at rest 1 year after the occurrence of cGVHD following an allogeneic bone marrow transplant (BMT). Pulmonary function data, imaging studies, lung biopsy, and bronchoalveolar lavage were consistent with the diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP). Although reports suggest that oral methylprednisolone or methylprednisolone pulse therapies improve BOOP after BMT, we treated our patient with a combination of oral prednisolone (1 mg/kg) and low dose erythromycin (10 mg/kg) to avoid the side-effects of high-dose steroids. With this therapy, our patient showed clinical and radiological improvements within 1 week. The steroids were tapered off 12 months later and erythromycin was given for 14 months. We conclude that therapy consisting of a combination of oral prednisolone and low-dose erythromycin for BOOP after BMT may minimize the dose and duration of steroid use.

Administration, Oral↗