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Biomedical subjects

T Isobe

Publications and source records attributed to T Isobe.

At least 37 records · Page 2Linked to original sources
PubMed1996

Reversed-phase liquid chromatography on a microspherical carbon column at high temperature.

The chromatographic conditions for the use of a spherical carbon column at high temperatures up to 160 degrees C are described. The column heating system and the eluate cooling system are also described. Under the conditions studied, it was found that the carbon column at elevated temperature was stable and could be applicable to any compounds that are durable under these conditions. The peptide bonds at this high temperature and at this acidity were still stable enough for analysis, but the indole residues showed poor stability.

Amino Acid Sequence↗
PubMed1996

Ultrastructural evidence for colocalization of kappa light chain- and beta 2-microglobulin-derived amyloids using double labelling immunogold electron microscopy.

In systemic amyloidosis, it is essential to decide what type of amyloid protein is deposited in tissues before the therapy can be selected and the prognosis assessed in each patient. We examined tissues affected by amyloid deposition from a patient with multiple myeloma by immunohistochemistry and double labelling immunogold electron microscopy and demonstrated colocalization of kappa light chain- and beta 2-microglobulin-derived amyloids in the same tissue. beta 2-Microglobulin-derived amyloid had ultrastructurally characteristic features that distinguished it from kappa light chain-derived amyloid. This is the first report of the colocalization of two different amyloids by immunoelectron microscopy.

Amyloid↗
PubMed1996

Changes in the gene expression of a protein with the cdc10/SWI6 motif, V-1, during rat follicular development and corpus luteum formation.

We examined the gene expression of V-1, a novel soluble protein with the cdc10/SWI6 motif, in pseudopregnant rat ovaries. Northern blot analysis on days 1, 5, and 11 of pseudopregnancy revealed an approximately 2-fold increase in the V-1 messenger RNA (mRNA) expression level on day 5 to that on day 1, and no significant change was observed between those on day 5 and day 11. An injection of human CG on days 5 further increased th V-1 mRNA level to about 1.6-fold of that of the untreated control. Western blot analysis showed higher V-1 protein expression on days 5 and 11 of pseudopregnancy than that on day 1. In situ hybridization and immunohistochemistry with ovaries on day 3 of pseudopregnancy showed that luteal cells of corpora lutea and also cells of the coexisting follicles including oocytes express V-1 mRNA and the protein, with apparent rank order of the expression: oocytes > luteal cells > follicular cells >> atretic follicular cells including oocytes. These data indicate the dynamic change in the V-1 gene expression in the ovarian steroidogenic cells and oocytes and suggest potential roles of the V-1 protein in ovarian functions including corpus luteum formation and folliculogenesis.

Animals↗
PubMed1996

[Ocular metastasis necessitating enucleation of an eyeball after surgery for primary lung cancer].

A 68-year-old man was referred because of an abnormal shadow in the right upper lung field on a chest X-ray film. After the diagnosis of adenocarcinoma of the lung, left upper lobectomy was done. Histologically, adenocarcinoma with foci of squamous cell carcinoma was seen. About 11 months after that operation, he suddenly noticed a decrease in visual acuity on the left side. The fundus of the eye was tested and metastatic choroidal cancer was suspected. To prevent rupture, the eyeball was enucleated. The choroidal tumor appeared to have components of squamous cell carcinoma from primary lung cancer. About 7 months after enucleation of his eyeball, the patient was disease-free with no decrease in his quality of life. As a result of a recent increase in the incidence of lung cancer, it is important to pay attention to ophthalmological tests in patients with primary lung cancer.

Adenocarcinoma↗
PubMed1996

[CT-image analysis of resected peripheral adenocarcinomas of the lung less than 1 cm in diameter].

Conventional CT (10-mm thick) and helical thin-section CT (2-mm thick) high-resolution images were obtained to study the relationship between the appearance of small peripheral adenocarcinomas of the lung and pathological findings. Eleven cases in which adenocarcinomas less than 1.0 cm in diameter were resected were retrospectively reviewed. Conventional CT images revealed air spaces within pulmonary nodules in 82% of tumors, an ill-defined margin in 91%, and involvement of vessels in 91%. When these findings are observed in pulmonary nodules, thin-section CT should be used for further examination. Helical thin-section CT images showed inhomogeneous internal attenuation (91%), irregularly undulating margins (91%), and vascular involvement (100%).

Adenocarcinoma↗
PubMed1995

Primary structure of a gamma subunit of G protein, gamma 12, and its phosphorylation by protein kinase C.

We have determined the primary structure of a novel gamma subunit (gamma 12, previously designated gamma S1) of G protein purified from bovine spleen. The mature gamma 12 protein composed of 68 amino acids had acetylated serine at the N terminus and geranylgeranylated/carboxylmethylated cysteine at the C terminus. This was consistent with the C-terminal prenylation signal in the amino acid sequence, which was predicted from gamma 12 cDNA isolated from a bovine spleen cDNA library. Western blots with the specific antibody against gamma 12 showed that gamma 12 is present in all tissues examined. Among various gamma subunits (gamma 1, gamma 2, gamma 3, gamma 7, and gamma 12), gamma 12 has a unique property to be phosphorylated by protein kinase C. The phosphorylated amino acid residue was Ser1 (or Ser2). The phosphorylated beta gamma 12 associated with Go alpha more tightly than the unphosphorylated form. Exposure of Swiss 3T3 and aortic smooth muscle cells to phorbol 12-myristate 13-acetate and NaF induced phosphorylation of gamma 12. Stimulation of aortic smooth muscle cells with natural vasoactive agents such as angiotensin II and vasopressin also induced phosphorylation of gamma 12. The extent of phosphorylation of beta gamma 12 in vitro was suppressed by a complex formation with Go alpha, which was relieved by the addition of guanosine 5'-O-(3-thiotriphosphate) or aluminum fluoride. These results strongly suggest that gamma 12 is phosphorylated by protein kinase C during activation of receptor(s) and G protein(s) in living cells.

Amino Acid Sequence↗
PubMed1995

Identification of the site of interaction of the 14-3-3 protein with phosphorylated tryptophan hydroxylase.

The 14-3-3 protein family plays a role in a wide variety of cell signaling processes including monoamine synthesis, exocytosis, and cell cycle regulation, but the structural requirements for the activity of this protein family are not known. We have previously shown that the 14-3-3 protein binds with and activates phosphorylated tryptophan hydroxylase (TPH, the rate-limiting enzyme in the biosynthesis of neurotransmitter serotonin) and proposed that this activity might be mediated through the COOH-terminal acidic region of the 14-3-3 molecules. In this report we demonstrate, using a series of truncation mutants of the 14-3-3 eta isoform expressed in Escherichia coli, that the COOH-terminal region, especially restricted in amino acids 171-213, binds indeed with the phosphorylated TPH. This restricted region, which we termed 14-3-3 box I, is one of the structural regions whose sequence is highly conserved beyond species, allowing that the plant 14-3-3 isoform (GF14) could also activate rat brain TPH. The 14-3-3 box I is the first functional region whose activity has directly been defined in the 14-3-3 sequence and may represent a common structural element whereby 14-3-3 interacts with other target proteins such as Raf-1 kinase. The result is consistent with the recently published crystal structure of this protein family, which suggests the importance of the negatively charged groove-like structure in the ligand binding.

14-3-3 Proteins↗
PubMed1995

Epiregulin. A novel epidermal growth factor with mitogenic activity for rat primary hepatocytes.

Epiregulin, a novel epidermal growth factor (EGF)-related growth regulating peptide, was purified from conditioned medium of the mouse fibroblast-derived tumor cell line NIH3T3/clone T7. It was a 46-amino-acid single chain polypeptide, and its amino acid sequence exhibited 24-50% amino acid sequence identity with sequences of other EGF-related growth factors. Epiregulin exhibited bifunctional regulatory properties: it inhibited the growth of several epithelial tumor cells and stimulated the growth of fibroblasts and various other types of cells. Epiregulin bound to the EGF receptors of epidermoid carcinoma A431 cells much more weakly than did EGF, but was nevertheless much more potent than EGF as a mitogen for rat primary hepatocytes and Balb/c 3T3 A31 fibroblasts. These findings suggest that epiregulin plays important roles in regulating the growth of epithelial cells and fibroblasts by binding to receptors for EGF-related ligands.

3T3 Cells↗
PubMed1995

Alterations in telomeric repeat length in lung cancer are associated with loss of heterozygosity in p53 and Rb.

In the two-stage model of controlling cellular senescence in cultured human fibroblasts, retinoblastoma (Rb) and p53 proteins may be key factors regulating the mortality stage 1 mechanism. In addition, the critical loss of telomeric DNA due to the end-replication problem may result in the mortality stage 2 mechanism. Cells which acquire telomerase activity can overcome the M2 mechanism by stabilizing telomere length and thus become immortal (telomere hypothesis). At present it is known whether cellular immortality is a prerequisite for all human cancers. To investigate this question and the applicability of the two-stage model to human cancers, we analysed the relationship between alterations of telomere length and other genetic changes in lung cancer. Among 60 primary lung cancer tissues, telomere length alterations were observed in 16 tumors (26.7%) including 14 with short and two with elongated telomeres. Ten of them revealed allelic loss of both p53 and Rb genes, and remaining six showed no abnormalities in both genes. We propose that inactivation of both p53 and Rb genes may promote cell divisions causing telomere shortening in lung cancer as in the two-stage model, while there may be another pathway to overcome both M1 and M2 mechanisms, especially for adenocarcinoma.

Base Sequence↗
PubMed1995

Purification and characterization of a novel 70-kDa brain protein associated with seizure activities.

Using ion exchange HPLC and ammonium sulfate precipitation, we have purified a 70-kDa protein (P70) specific to the cobalt-induced epileptogenic cortex of rat cerebrum and determined certain of its biochemical properties. P70 has a similar isoelectric point (pI; 4.6-4.8), amino acid composition and N-terminal amino acid sequence to rat serum albumin (RSA). Intracortical application of purified P70 to the motor area of normal rat cerebrum induces both ECoG seizure discharges and behavioral seizures. The data suggest that P70 is a novel albumin-like protein linked to the generation of seizure activities. However, it can be clearly distinguished from RSA, since it is able to produce seizure, is a glycoprotein and can be readily separated from RSA by 2-dimensional electrophoresis.

Albumins↗
PubMed1995

Combination assay of urinary beta-core fragment of human chorionic gonadotropin with serum tumor markers in gynecologic cancers.

Ectopic production of the immunoreactive beta-subunit of human chorionic gonadotropin (IR-hCG beta) by gynecologic malignancies has been well recognized, but IR-hCG beta has not yet been established as a clinically useful tumor marker, except for germ cell tumors. We measured the concentrations of IR-hCG beta-related molecules, intact hCG, free hCG beta, and beta-CF, in the sera and urine of patients with various gynecologic cancers (cervical, endometrial, and ovarian cancers) to assess their clinical usefulness as a tumor marker in comparison with serum tumor markers such as CEA, SCC, CA125, and CA19-9. The highest incidence of IR-hCG beta was obtained in the assay for beta-CF in the urine, with positive rates of 47.7% (94 of 197) for cervical, 37.8% (14 of 37) for endometrial, and 84.4% (38 of 45) for ovarian cancers with a cut-off value of 0.2 ng/mg of creatinine. In cervical cancer, there was no significant correlation between the concentrations of urinary beta-CF and serum SCC, and 57.9% (114 of 197) of the patients were detected by the combination assay of these tumor markers. Serial determination in 22 cervical cancer patients with elevated urinary beta-CF level prior to therapy showed that its level decreased after successful treatment, but 4 of 5 patients with persistent or recurrent disease had elevated levels of urinary beta-CF. All of the ovarian cancer patients examined were detected by the combination assay of urinary beta-CF and serum CA125. The levels of urinary beta-CF showed little correlation with those of the serum tumor markers, indicating the usefulness of the combination assay of urinary beta-CF with serum tumor markers for detecting cervical and ovarian cancers.

Biomarkers, Tumor↗
PubMed1995

Establishment of a myeloid leukaemic cell line (SKNO-1) from a patient with t(8;21) who acquired monosomy 17 during disease progression.

A novel cell line SKNO-1 was established from the bone marrow cells of a 22-year-old male suffering from acute myeloblastic leukaemia (AML) M2 with t(8;21) whose disease became resistant to chemotherapy after acquisition of 17 monosomy. SKNO-1 has been maintained for more than 36 months as a granulocyte-macrophage colony-stimulating factor (GM-CSF) dependent line. Morphologically, SKNO-1 cells were myeloblasts somewhat matured. The cells grow in suspension with a doubling time of 48-72 h. The survival and growth of SKNO-1 cells was absolutely dependent on granulocyte-macrophage colony stimulating factor (GM-CSF). SKNO-1 cells possessed t(8;21) and monosomy 17 which were observed in original leukaemic cells. We confirmed that the AML1 gene, located on chromosome 21, was rearranged and the AML1-MTG8 fusion transcript was expressed in SKNO-1 cells. Over-expression and mutation of the p53 gene were also detected in SKNO-1. It is likely that alterations of AML1 or MTG8 gene and p53 gene contribute to a disease progression in this case. Since t(8;21) translocation is a common chromosome abnormality in AML, and inactivation of the p53 gene may play a crucial role in disease progression in AML, SKNO-1 would be a useful tool for analysing the molecular mechanisms in myeloid leukaemogenesis.

Adult↗
PubMed1995

Systemic capillary leak syndrome associated with multiple myeloma of IgG kappa type.

A case of systemic capillary leak syndrome in a 67-year-old woman is reported. The patient suddenly presented with severe edema and hypotension associated with an increased hematocrit and a decreased level of serum albumin, suggesting capillary hyperpermeability. The patient had IgG kappa monoclonal gammopathy in association with not only a slight increase in plasma cells in the bone marrow but also several punched out lesions in the skull, indicating multiple myeloma. Although most of the cases of systemic capillary leak syndrome reported previously were accompanied by monoclonal gammopathy, this appears to be the first case in which capillary leak syndrome developed in a patient with multiple myeloma.

Aged↗
PubMed1995

[Application of molecular diagnosis to human lung cancer].

Recent developments in the molecular genetics of human cancers shows the importance of multiple genetic alterations in the pathogenesis of these lesions. DNA diagnostic techniques are being introduced rapidly into the clinical laboratory setting. 1) In lung cancer, several oncogenes and tumor suppressor genes, such as ras, myc, p53, RB, allelic loss of chromosomes, play very important roles. These genetic changes are being applied to cancer diagnosis, prediction of prognosis or disease metastasis, or response to treatment. 2) Drug resistance is one of the major problems of current lung cancer chemotherapy. Identification of the molecular marker for drug resistance, like DNA topoisomerase gene mutation, in clinical samples will be of great help for choosing chemotherapy regimens. 3) Interindividual differences in susceptibility to lung cancer may be screened using genotyping of the P450IA1 and GSTmu genes. To develop newer diagnostic and therapeutic approaches, detailed investigation of the molecular pathogenesis of lung cancer using clinical samples is essential. I review the present status on these applications of genetic markers to lung cancer diagnosis in this article.

DNA Topoisomerases, Type I↗