Abnormal expression of mouse mast cell protease 5 gene in cultured mast cells derived from mutant mi/mi mice.

Mast cells contain a lot of mast cell-specific proteases. We have reported that the expression of mouse mast cell protease 6 (MMCP-6) is remarkably reduced in both cultured mast cells (CMCs) and skin mast cells of mi/mi mutant mice. In the present study, we found that the expression of MMCP-5 was reduced in CMCs but not in skin mast cells of mi/mi mice, and we compared the regulation mechanisms of MMCP-5 with those of MMCP-6.

IL-12-induced tumor regression correlates with in situ activity of IFN-gamma produced by tumor-infiltrating cells and its secondary induction of anti-tumor pathways.

Administration of recombinant interleukin-12 (rIL-12) into CSA1M fibrosarcoma-bearing mice results in complete regression of growing tumors. This tumor regression is associated with massive lymphoid cell infiltration to tumor sites and is completely blocked by injection of anti-interferon-gamma (IFN-gamma) monoclonal antibody (mAb). We investigated whether anti-IFN-gamma mAb exerts its suppressive effect on tumor regression by blocking the IL-12-induced lymphoid cell migration to tumor sites or by inhibiting the secondary effects of IFN-gamma produced by infiltrating cells.

Preclinical Cushing's syndrome due to adrenocorticotropin-independent bilateral adrenocortical macronodular hyperplasia with concurrent excess of gluco- and mineralocorticoids.

A 48-year-old with bilateral adrenal incidentalomas was studied. Although the serum cortisol level was normal, autonomous cortisol secretion was shown by the loss of diurnal rhythm, no suppressibility by dexamethasone, and complete suppression of plasma adrenocorticotropin levels. Imaging analyses revealed bilateral adrenal masses, showing isotope uptake.

Molecular cloning of cDNA encoding the c-kit receptor of Shiba goats and a novel alanine insertion specific to goats and sheep in the kinase insert region.

The complete open reading frame (ORF) of the c-kit cDNA was cloned from a cerebellar cDNA library of the Shiba goat (Capra hircus var Shiba) with the dominant black-eyed white phenotype. The analysis of the deduced amino acid sequence revealed the presence of a single amino acid insertion (alanine) in the kinase insert (KI) region. While the newly found alanine insertion is not correlated with the coat color phenotype of goats, it appears to be characteristic of the c-kit genes in goats and sheep.

Mechanisms of constitutive activation of c-kit receptor tyrosine kinase.

We investigated the mechanism of constitutive activation of c-kit receptor tyrosine kinase (KIT) found in the FMA3 murine mastocytoma cell line, and compared it with the mechanisms observed in other tumor mast cell lines (the HMC-1 human mast cell leukemia cell line, the RBL-2H3 rat mast cell leukemia cell line, and the P-815 murine mastocytoma cell line). The c-kit gene obtained from FMA3 cells was found to have 21-base deletion at the juxtamembrane domain of KIT, thereby leading to the constitutive activation of KIT. The deletion at the juxtamembrane domain resulted in constitutive dimerization of c-kit proteins, whereas the point mutation that were detected at the kinase domain of KIT in HMC-1, RBL-2H3, and P-815 cells caused constitutive activation of KIT without dimerization.

Role of c-kit receptor tyrosine kinase in the development, survival and neoplastic transformation of mast cells.

The c-kit gene is allelic with the dominant spotting (W) locus on mouse chromosome 5 and encodes a receptor tyrosine kinase. The ligand for c-kit receptor is stem cell factor (SCF), which is the principal growth factor for mast cells. The loss-of-function mutations of c-kit receptor affect the development of mast cells, thereby resulting in a depletion of mast cells.

O6-methylguanine induces intrachromosomal homologous recombination in human cells.

N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which alkylates many positions in DNA including the 06 position of guanine, efficiently induces intrachromosomal homologous recombination in mouse L-cells. To investigate the role of 06-methylguanine in the induction of homologous recombination in human cells, three cell strains containing duplicated copies of the Herpes simplex virus I thymidine kinase (Htk) gene and three cell strains containing duplicated copies of the gene coding for hygromycin phosphotransferase (hyg) were treated with MNNG. Neither the Htk genes nor the hyg genes code for a functional enzyme because each contains an insertion mutation at a unique site, i.

Regulation of mouse mast cell protease 6 gene expression by transcription factor encoded by the mi locus.

The mi locus of mice encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (hereafter called MITF). Because the expression of the mouse mast cell protease 6 (MMCP-6) gene is remarkably reduced in mast cells of mi/mi mutant mice, we investigated the effect of MITF on the transcription of the MMCP-6 gene. First, we introduced the normal (+) MITF cDNA into mi/mi cultured mast cells using the retroviral vector.

Inhibition of growth and metastasis of ovarian carcinoma by administering a drug capable of interfering with vascular endothelial growth factor activity.

The present study investigates the relationship between in vivo growth/metastasis of tumor cells and their capacity to produce the vascular endothelial growth factor (VEGF), as well as the regulation of tumor growth/metastasis using an angiogenesis-inhibitory drug. Two cloned tumor cell lines designated OV-LM and OV-HM were isolated from a murine ovarian carcinoma OV2944. OV-LM and OV-HM cells grew in cultures at comparable rates.

Involvement of transcription factor encoded by the mi locus in the expression of c-kit receptor tyrosine kinase in cultured mast cells of mice.

The mi locus of mice encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (hereafter called MITF). Cultured mast cells of mi/mi genotype (mi/mi CMCs) did not normally respond to stem cell factor (SCF), a ligand for the c-kit receptor tyrosine kinase. The poor response of mi/mi CMCs to SCF was attributed to the deficient expression of c-kit both the mRNA and protein levels.

Neoplastic transformation of normal hematopoietic cells by constitutively activating mutations of c-kit receptor tyrosine kinase.

The c-kit proto-oncogene encodes a receptor tyrosine kinase that is crucial to hematopoiesis, melanogenesis, and gametogeneis. Although the enzymatic activity of the c-kit product (KIT) is regulated by its ligand, both the Val559-->Gly (G559) mutation in the juxtamembrane domain and the Asp814-->Val (V814) mutation in the phosphotransferase domain lead to constitutive activation of KIT. By retroviral infection of hematopoietic progenitor cells with KIT(G559) or KIT(V814), KIT(G559) induced development of granulocyte/macrophage and mast-cell colonies in vitro without the addition of exogenous growth factors.

Phosphaturic mesenchymal tumor, mixed connective tissue variant (oncogenic osteomalacia).

A case of tumor-induced phosphaturic osteomalacia in a 54 year old man is reported. The patient was admitted because of progressive muscle spasms with pain and weakness in the bilateral thighs. Laboratory data showed hypophosphatemia, decreased tubular resorption of phosphate (TRP), a low 1,25-dihydroxyvitamin D level, and a high serum alkaline phosphatase level.

Role of aspartic acid 814 in the function and expression of c-kit receptor tyrosine kinase.

The c-kit receptor tyrosine kinase (KIT) is constitutively activated in three different types of neoplastic mast cell lines by naturally occurring mutations that result in substitutions of Val or Tyr for Asp814 in the phosphotransferase domain. In an effort to characterize the role of the Asp814 residue, we have investigated the properties of mutant KITs in which the Asp814 residue was deleted or mutated to a series of other amino acids. With the exception of rare instances, mutant KITs with substitutions of Asp814 were found to be constitutively phosphorylated on tyrosine and activated in the absence of the ligand, stem cell factor (SCF), whereas a deletion mutant lacking Asp814 (KITDel-Asp-814) did not exhibit tyrosine phosphorylation and activation even after treatment with SCF.

Kimura disease: CT and MR findings.

The lesions of Kimura disease showed slightly high and very high intensity on T2-weighted MR, and low and intermediate intensity, respectively, on T1-weighted images. The degree of enhancement also differed between the two cases. These discrepancies may be attributable to differing degrees of fibrosis and vascular proliferation.

Expression of multiple c-kit receptor messenger ribonucleic acid transcripts during postnatal development of the rat testis.

The c-kit protooncogene is a transmembrane tyrosine kinase receptor expressed during gametogenesis. Using the polymerase chain reaction (PCR), we have identified the c-kit receptor mRNA transcripts in the rat testis and studied their expression during postnatal development of the testis. Five different transcripts were identified using sets of primers encoding within the extracellular domain.

Tenascin expression in adenoid basal cell carcinoma of the skin.

The immunoreactivity of tenascin, an extra cellular matrix glycoprotein, spatially and temporarily expressed in a site restricted manner during embryogenesis, wound healing and various benign and malignant tumours, was evaluated in 24 cases of adenoid basal cell carcinoma of the skin. The expression of tenascin showed three distinct patterns: firstly, the expression was confined to the stroma surrounding the tumour cells, secondly, to the stromal tissues of epithelial tumour foci and lumens of cribriform or cyst-like epithelial structures, and finally, a mixed pattern of these two was seen. It is suggested that in addition to the stromal reactivity, epithelial tumour cells may produce tenascin to deposit into the cribriform cystic lumens in the adenoid basal cell carcinoma in the skin.

Constitutive activation of c-kit in FMA3 murine mastocytoma cells caused by deletion of seven amino acids at the juxtamembrane domain.

A peculiar point mutation results in constitutive activation of c-kit receptor tyrosine kinase (KIT) in three different tumor mast cell lines; ie, the HMC-1, P-815, and RBL-2H3. Because constitutive activation of KIT was also observed in the FMA3 mouse mastocytoma cell line, we investigated the molecular mechanism. Sequencing of the whole coding region of the c-kit showed that the point mutation found in HMC-1, P-815, and RBL-2H3 cells was absent in FMA3 cells and that the c-kit cDNA of FMA3 cells carried an in-frame deletion of 21 base pairs (bp) encoding Thr-Gln-Leu-Pro-Tyr-Asp-His at codons 573 to 579 at the juxtamembrane domain.

Transforming and differentiation-inducing potential of constitutively activated c-kit mutant genes in the IC-2 murine interleukin-3-dependent mast cell line.

Two mutations of c-kit receptor tyrosine kinase (KIT), valine-559 to glycine (G559) and aspartic acid-814 to valine (V814), resulted in its constitutive activation. To examine the transforming and differentiation-inducing potential of the mutant KIT, we used the murine interleukin-3-dependent IC-2 mast cell line as a transfectant. The IC-2 cells contained few basophilic granules and did not express KIT on the surface.

Pyruvate kinase deficiency of mice associated with nonspherocytic hemolytic anemia and cure of the anemia by marrow transplantation without host irradiation.

Mutant mice with splenomegaly and nonspherocytic hemolytic anemia were found in an inbred colony of the CBA/N (hereafter CBA) strain maintained in the Japan SLC Haruno farm (Shuchi-gun, Shizuoka, Japan). The activity of pyruvate kinase (PK) in red blood cells (RBCs) of the anemic mutants decreased to 16.2% of normal (+/+) CBA mice.

Primary structure of murine red blood cell-type pyruvate kinase (PK) and molecular characterization of PK deficiency identified in the CBA strain.

To clarify the molecular abnormality of pyruvate kinase (PK) deficiency identified in the mutant mice of CBA-Pk-1slc/Pk-1slc, we cloned murine red blood cell-type PK (R-PK) cDNA of those animals. The cDNA sequence spans 1827 bp, including an open reading frame that can encode 574 amino acids. Homology in the coding sequences between murine and human R-PK was 86.

Growth response of acute myeloblastic leukemia cells to recombinant human thrombopoietin.

Thrombopoietin (TPO) is a newly identified hematopoietic growth factor that stimulates both megakaryopoiesis and thrombopoiesis through its interaction with a specific cell surface receptor encoded by the c-mpl proto-oncogene. In an effort to investigate the effect of TPO on human myeloid leukemia cells, the expression of c-mpl and the proliferative response to recombinant human (rh) TPO were investigated in a series of patients with acute myeloblastic leukemia (AML). Of 50 cases of AML, the c-mpl mRNA was detectable by means of Northern blot analysis in 26 cases, and the in vitro treatment with rhTPO led to proliferation of AML cells in 22 cases.

Recurrent primary central nervous system lymphoma mimicking neurodegenerative disease--an autopsy case report.

A 42-year-old female presented with recurrent primary central nervous system lymphoma mimicking the roentgenographic appearance of diffuse brain degeneration. Betamethazone was administered, but her condition worsened. Biopsy of a swollen neck lymph node demonstrated lymphoma cells.

Regulation of development, survival and neoplastic growth of mast cells through the c-kit receptor.

Signaling through the c-kit receptor tyrosine kinase (Kit) is essential for development and survival of mast cells but not of basophils. Moreover, we recently found an activation mutation of Kit in several tumor mast cell lines.

Substitution of an aspartic acid results in constitutive activation of c-kit receptor tyrosine kinase in a rat tumor mast cell line RBL-2H3.

The c-kit protooncogene encodes a receptor tyrosine kinase that mediates signals required for differentiation, proliferation and survival of mast cells. We have already shown the constitutive activation of c-kit receptor tyrosine kinase (KIT) in a human mast cell leukemia line (HMC-1) and a murine mastocytoma cell line (P-815). We here examined whether such constitutive activation of KIT occurred in the rat tumor mast cell line RBL-2H3 as well, which is frequently used as a tool for studying functions of mast cells.