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Biomedical subjects

K Tsuboi

Publications and source records attributed to K Tsuboi.

At least 109 records · Page 6Linked to original sources
PubMed1989

Differential expression of N-myc and c-src proto-oncogenes during neuronal and schwannian differentiation of human neuroblastoma cells.

Neuroblastoma (NB) cells can be induced to differentiate bidirectionally into either neuronal or schwannian cells by different inducers. However, the underlying mechanisms are poorly understood. We examined the expression of N-myc and c-src genes in 3 human NB-cell lines during either neuronal or schwannian differentiation in vitro, since proto-oncogenes are considered to play a pivotal role in regulating cell proliferation and differentiation. Decreased N-myc expression and increased c-src expression were observed during neuronal differentiation by retinoic acid, polyprenoic acid (E5166) and dibutyryl cyclic AMP, whereas the expression of N-myc and c-src genes was considerably reduced during schwannian differentiation by bromodeoxyuridine, demonstrating that the expression of N-myc and c-src genes was regulated independently in the bipolar differentiation processes of NB cells. Our results suggest that enhanced N-myc expression might be closely linked to the undifferentiated phenotypes of NB cells, that c-src expression might be related to the neuronal differentiation of NB cells, and that N-myc and c-src genes might be regulated independently in the determination of the bipolar differentiation of NB cells.

Cell Differentiation↗
PubMed1989

[Tooth extraction in a case of thrombasthenia].

Thrombasthenia is a congenital platelet disorder characterized by the normal platelet count, prolonged bleedingtime, absence of platelet aggregation and defective clot retraction. Clinically, purpura, epistaxis, gingival bleeding and excessive bleeding after minor injuries or operations are the main manifestations. We experienced a case of a 15-year-old boy suffering from thrombasthenia required extraction of 6/6. The problems of nature of the disease and its familial character are described and the problems of management are outlined.

Adolescent↗
PubMed1989

[Electron microscopic study on malignant fibrous histiocytoma induced by local application of DMBA heterotransplanted in nude mice].

Though Malignant Fibrous Histiocytoma (MFH) has been regarded as a relatively common neoplasm of the mesenchymal soft tissues, the issue of character is largely unresolvable at present. Our department formerly reported that produced experimental MFH by administering 9, 10-dimethyl-1, 2-benzanthracene (DMBA) in male hamsters. In this study I have examined the fine structure of transplantation and heterotransplantation of MFH. The following results were obtained. 1. Five different types of cells were found in the MFH: fibroblast-like cells, histiocyte-like cells, undifferentiated cells, multinucleated giant cells and xanthomatous cells. 2. In histiocyte-like cells, nonphagocytic and actively phagocytic histiocyte-like cells could be distinguished. 3. The multinucleated giant cells could be found two types, fibroblast-like and histiocyte-like. 4. In transplantation, the histology of the original tumor was retained. 5. In heterotransplantation, the tumor was composed mainly of nonphagocytic histiocyte-like cells and undifferentiated cells. 6. The possibility is suggested that both principal cell types in this tumor may derive from the same undifferentiated stem cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

[A case of carcinoma of the tongue treated with neoadjuvant chemotherapy].

A case of carcinoma of the tongue treated with neoadjuvant chemotherapy has been reported. The patient was a 61-year-old man complaining of tumor and contact pain at the left margin of the tongue. The tumor was oval and elastic soft with pedicle, measuring 26 X 16 X 8 mm in size. The tumor was histopathologically diagnosed as a highly differentiated squamous cell carcinoma. The patient was treated with CDDP (75 mg/body) and PEP (5 mg/body) for 5 days. After two trials with about a 3-week interval, treatment result showed partial response. This result demonstrated that combination chemotherapy of CDDP and PEP is an effective regimen for remission neoadjuvant chemotherapy in patients with squamous cell carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Tumor cord and growth in human brain tumors based on mathematical morphology.

The growth of human brain tumor was quantitatively investigated by using the anti-bromodeoxyuridine (BrdU) monoclonal antibody and the texture analyzing system (TAS). Tissues from thirty eight patients consisting of 22 gliomas, 8 brain metastases, 1 cerebellar hemangioblastoma and 7 normal white matters were applied in this study. Mean values of growth fractions (GFs) were 29.4% in group 1, 14.8% in group 2, and 6.5% in group 3. The higher value of GFs showed a significantly larger degree of perivascular aggregation of S-phase cells (DPAS). The mean number of cells in each tumor cord was approximately 20, which is not significantly larger than that of the normal group. But there was a significant difference between the non-selected area of the histologically malignant or benign gliomas and the proliferating area of the biologically malignant or benign brain tumors (t-value; p less than 0.001). A significant difference was also noticed in the mean area and diameter of tumor cords (t-value; p less than 0.001). From the point of view of biological behavior in human brain tumor, it is suggested that one tumor cord contains approximately 20 viable cells in the proliferating area in both benign and malignant brain tumors, and that if viable cells increase to more than 20 cells in one TC, necrotic cells and the diameter and area of the TC will increase, because the vessel-density is decreased by the occlusion of the vessels and the death of the endothels.

Brain Neoplasms↗
PubMed1987

Expression of the c-myc gene in human gastrointestinal malignancies.

We have examined the level of the c-myc transcript in 6 esophageal, 16 gastric, 19 colorectal and 1 anal cancer tissue samples; these included four lymph nodes and six hepatic metastases obtained surgically. The esophageal cancer tissues were without an increase of the c-myc transcript, some of the gastric cancer samples showed a two to three fold increase and most of the colorectal and the one anal cancer samples showed a two to ten fold increase when compared with a normal mucosal layer. Therefore, the level of the c-myc transcript in human gastrointestinal malignancies shows organ dependency. Local, lymphatic, and hepatic metastases showed little difference in the level of c-myc mRNA from that of the primary tumor.

Actins↗
PubMed1987

[Hyperthyroidism due to a TSH-secreting pituitary tumor].

A 28-year-old female with a 12-year history of goiter is presented. She had both clinical and laboratory evidence of hyperthyroidism, and her serum TSH was persistently and markedly elevated after treatment with antithyroid drugs. A TRH stimulation test resulted in no further rise in serum TSH after cessation of medication. Menses were regular and serum prolactin levels were normal. Serum LH and FSH responses to LHRH stimulation test were normal. No other evidence of pituitary or peripheral endocrine deficiencies existed. She underwent a subtotal thyroidectomy followed by 131I therapy three years later. A pituitary adenoma with sphenoidal and suprasellar extension was completely removed by transphenoidal approach. On light microscopy, it was mostly composed of chromophobic cells with occasional calcification showing sinusoidal pattern. On electron microscopy, most of the cells contained fine granules, which suggested thyrotroph. The immunoperoxidase technique revealed TSH beta in the cytoplasm of some adenoma cells. Three days postoperatively the patient's serum TSH levels returned to normal. TRH stimulation test produced a normal response in serum TSH. The patient was diagnosed hypothyroid by laboratory findings and is currently on thyroid replacement therapy. The patient became pregnant and delivered twice prior to the operation for pituitary adenoma. The previously reported TSH secreting adenomas associated with hyperthyroidism were reviewed.

Adenoma↗