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Biomedical subjects

Kentaro Yokoi

Publications and source records attributed to Kentaro Yokoi.

15 recordsLinked to original sources
PubMed2006

Sequential analysis of cadherin expression in a 4-year-old girl with intracranial ependymoma.

INTRODUCTION: Cadherins are Ca(2+)-dependent cell-to-cell adhesion molecules that play an important role in tissue construction and morphogenesis in multicellular organisms. Cadherin involvement in tumor metastasis has recently been reported. CASE REPORT: We investigated the expression of E-cadherin and N-cadherin in paraffin-embedded sequential surgical specimens and autopsy specimens from a 4-year-old girl with recurrent ependymoma, subsequent to cerebrospinal fluid (CSF) dissemination. We observed low expression of E-cadherin in all surgical specimens and autopsy specimens. In contrast, expression of N-cadherin was high in all surgical specimens, but was decreased in autopsy specimens. CONCLUSION: Decreased expression of N-cadherin may be associated with CSF dissemination and may serve as a useful marker for CSF dissemination in patients with intracranial ependymoma.

Autopsy↗
PubMed2006

Lymphocytic hypophysitis with central diabetes insipidus and subsequent hypopituitarism masking a suprasellar germinoma in a 13-year-old girl.

CASE REPORT: We report a case of central diabetes insipidus, hypothyroidism, and subsequent hypopituitarism due to lymphocytic hypophysitis masking a germinoma in a 13-year-old pubertal girl. Magnetic resonance revealed an enlarged pituitary gland and a mass lesion in the pituitary stalk and inferior hypothalamus. Open cranial surgery of the anterior pituitary showed active hypophysitis with lymphocytic infiltrates but without necrosis. Despite prednisolone therapy, 1 year later an enlarged, irregular cystic mass lesion had developed; in the pituitary stalk and inferior hypothalamus, a endoscopic biopsy revealed germinoma. CONCLUSION: Lymphocytic hypophysitis in children may be the first sign of a host reaction to an occult germinoma. The diagnosis of central diabetes insipidus with a thickened pituitary stalk requires long-term follow-up to establish the underlying cause.

Adolescent↗
PubMed2006

Hemoglobin Hammersmith [beta 42(CD1) Phe --> Ser] causing severe hemolytic anemia in a Japanese girl.

Hemoglobin Hammersmith, a rare, unstable hemoglobin variant, was diagnosed in a 9-year-old Japanese girl. She presented with the typical manifestations of this disorder, including neonatal hyperbilirubinemia, followed by progressive hepatosplenomegaly, jaundice, and bilirubinuria. Because of severe hemolytic anemia, she received transfusions of red blood cells every 3 to 4 weeks. However, she underwent splenectomy at the age of 4 years and has continued to be in partial remission without requiring further transfusions. DNA sequence analysis of the polymerase chain reaction-amplified beta-globin gene revealed a point mutation (T --> C) in the second nucleotide of the 42nd codon of the beta-globin chain (beta 42(CD1) Phe --> Ser).

Anemia, Hemolytic, Congenital↗
PubMed2005

Successful treatment of Diamond-Blackfan anemia with metoclopramide.

Diamond-Blackfan anemia (DBA) is a congenital anemia characterized by a low reticulocyte count, the absence or severe reduction of hemoglobin-containing cells in the bone marrow, and normal megakaryocytic and granulocytic differentiation. Although the anemia may initially respond to corticosteroid therapy, many patients require lifelong red blood cell (RBC) transfusion, leading to infectious complications and iron overload. Metoclopramide has recently been used to treat DBA. Treatment with metoclopramide induces the release of prolactin from the pituitary and stimulates erythropoiesis. For these reasons, we used metoclopramide to treat a 20-year-old man with DBA refractory to low and high doses of corticosteroids, cyclosporin A, and tacrolimus (FK506). The hemoglobin and hematocrit slowly increased, and he has remained asymptomatic and transfusion-independent for 8 months. Metoclopramide therapy should be considered in patients with refractory DBA before treatment-related complications develop.

Adult↗
PubMed2005

RNA expression analysis of a congenital intracranial teratoma.

Congenital intracranial tumors are extremely rare and account only for 0.5%-1.5% of brain tumors in children. We report a large intrauterine congenital teratoma in a female fetus at gestation weeks 37, which was diagnosed by detecting the tumor and associated craniomegaly with ultrasonography (US) and magnetic resonance (MR) imaging. The tumor had replaced the cerebral hemispheres and produced prenatal manifestations. Pathologic examination showed an immature teratoma, which was differentiated from all three germ layers. Microarray analysis revealed upregulation of ten genes and downregulation of three genes, as well as upregulation of 41 genes of ribosomal proteins in teratoma cells, compared to normal brain tissue of the patient. The data from the microarray analysis offer not only the potential to help define disease pathogenesis but may also provide clues to identify potential molecular therapeutic targets.

Adult↗
PubMed2005

First description of somatic mosaicism in MYH9 disorders.

MYH9 disorders are characterized by giant platelets, thrombocytopenia, and Dohle body-like cytoplasmic granulocyte inclusion bodies that result from mutations in MYH9, which encodes non-muscle myosin heavy chain-A (NMMHCA). These disorders are known to be transmitted in an autosomal dominant manner, although about 20% of cases are considered to be sporadic. We report here the first case of a MYH9 disorder because of somatic mosaicism. The patient was the father of a male with typical May-Hegglin anomaly. The father had normal platelet counts, however, both normal-sized and giant platelets were observed on his peripheral blood smears. In addition, 14% of neutrophils contained inclusion bodies and the rest showed a normal morphology. Quantitative fluorescent polymerase chain reaction analysis showed that only 6% of DNA from peripheral blood leucocytes harboured the mutation. The mosaicism was demonstrated at a similar rate in different tissues, buccal mucosa cells and hair bulb cells, implying that the mutation had occurred before gastrulation. Mosaicism might account for some de novo mutations in MYH9 disorders.

Base Sequence↗
PubMed2005

Rapidly progressive IgA nephropathy.

A 14-year-old boy presented with macroscopic hematuria and a rapid deterioration in renal function. Percutaneous renal biopsy demonstrated severe crescentic IgA nephropathy (IgAN) with extensive (88%) glomerular crescent formation. After started intravenous administration of high-dose pulse methylprednisolone, severe nausea and general malaise accompanied by a rapid increase in Blood Urea Nitrogen (BUN) and serum creatinine levels appeared, however, the renal function ameliorated rapidly and fully recovered by following oral administration of corticosteroid. The clinical presentation of our case seems to be very remarkable compared to previously reported cases of rapidly progressive IgAN.

Adolescent↗
PubMed2005

[A woman complicated with immune thrombocytopenic purpura, subclinical Graves disease and peripheral neuropathy 5 years after allogeneic bone marrow transplantation].

A 21-year-old woman developed immune thrombocytopenia (ITP), subclinical Graves disease and peripheral neuropathy without typical chronic graft-versus-host disease (GVHD) 5 years following an allogeneic bone marrow transplantation from an HLA-identical sibling. She received high-dose intravenous immunoglobulin (IVIG) and prednisolone (PSL), which resulted in transient recovery of platelet numbers and muscle weakness. A combination of cyclosporine and PSL induced a durable response against not only the thrombocytopenia but also her high levels of thyroid stimulating antibody (TSAb), muscle weakness and sensory abnormality. The level of thyroglobulin in the donor, who had not developed Graves disease, was also elevated, indicating that late onset-subclinical Graves disease was caused by donor lymphocytes that were autoreactive to the thyroid glands.

Adult↗
PubMed2004

TNFalpha induces rapid activation and nuclear translocation of telomerase in human lymphocytes.

Maintenance of telomeres regulates chromosomal stability and cellular mitosis through a checkpoint mechanism. Continuous cell proliferation requires telomerase to maintain chromosomal stability and to counteract the cellular mitotic clock. Importantly, nuclear expression of telomerase activity is required for elongation of telomere sequences. In this study, we show that tumor necrosis factor alpha (TNFalpha) induces telomerase activity in the cytoplasm of peripheral blood lymphocytes (PBL) at 60 min, followed by translocation of activated telomerase to the nucleus at 120 min. Conversely, the phosphoinositol 3-kinase (PI3K) inhibitor wortmannin blocks TNFalpha-induced activation of telomerase, whereas the specific NF-kappaB translocation inhibitor SN-50 blocks TNFalpha-induced nuclear translocation of activated telomerase. These studies suggest that activation and nuclear translocation of telomerase are regulated by PI3K/Akt/NF-kappaB signaling pathways in PBL.

Active Transport, Cell Nucleus↗
PubMed2004

[Granulocyte transfusions for severe infections prior to allogeneic hematopoietic stem cell transplantation].

The efficacy and safety of granulocyte transfusions were evaluated in two acute lymphoblastic leukemia patients for the control of severe infections (cervical cellulitis, sepsis) prior to hematopoietic stem cell transplantation. One patient received 6 transfusions and the other 2 transfusions. The donors were given subcutaneous granulocyte-colony stimulating factor plus oral dexamethasone/betamethasone 12 hours before the scheduled collection. Granulocytes were obtained by standard leukapheresis procedures utilizing hydroxyethyl starch with processing of 7 liters of blood. The yield was 3.2-10.7 x 10(10) (0.7-2.1 x 10(9)/kg of recipient) granulocytes. Post-transfusion increases of peripheral blood neutrophil counts in the following morning were 300 to approximately 6,900/ml. Infections resolved and successful engraftment was obtained in both patients after the transplants. No severe adverse reactions were observed. These findings suggest that granulocyte transfusions are useful for control of severe infections prior to allogeneic hematopoietic stem cell transplantation.

Adolescent↗