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Y Mishima

Publications and source records attributed to Y Mishima.

At least 19 recordsLinked to original sources
PubMed1992

A single-stranded DNA binding protein from mouse tumor cells specifically recognizes the C-rich strand of the (AGG:CCT)n repeats that can alter DNA conformation.

A protein that binds to a synthetic oligonucleotide of (CCT)12 has been purified from Ehrlich ascites tumor cells by a (CCT)12 affinity chromatography. The protein (p70) has an apparent molecular mass of 70 kDa, as assayed by Southwestern analysis. A competition experiment revealed that p70 binds to (CCT)12, (CCCT)8 and (CCTCCCT)6, but not to (CTT)12, (CT)16 and (CCTGCCT)6, suggesting that p70 has a sequence-specificity. The complementary (AGG)12 and the double stranded DNA did not show the binding. It is also confirmed by S1 nuclease analysis that the (AGG:CCT)12 duplex takes a single-stranded conformation in the absence of the protein. This raises a possibility that the duplex forms two single-stranded loops in chromosomes, the C-rich strand being bound to p70. Structural analysis of the resulting (AGG)12 strand by non-denaturing polyacrylamide gel electrophoresis demonstrated the presence of slower and faster migrated conformers in a neutral pH buffer containing 50 mM NaCl at 5 degrees C. The ratio was dependent on the DNA concentration. Both conformers disappeared in the absence of NaCl. This suggests that (AGG)12 can form intra- and inter-molecular complexes by non-Watson-Crick, guanine:guanine base-pairing. The possible biological function of the (AGG:CCT)n duplex and the p70 is discussed.

Animals↗
PubMed1992

A 35-kDa protein binding to a cytosine-rich strand of hypervariable minisatellite DNA.

A minisatellite-binding protein, Msbp-4, with a molecular mass of 35 kDa has been purified from mouse tumor cells that binds to hypervariable Pc-1 and Pc-2 minisatellites. The binding is much more efficient than that to genetically stable minisatellite homologues. As assayed by Southwestern analysis, Msbp-4 favors multiple copies of the Pc-2 repeat sequence GGCAGGA and requires the cytosine-rich single strand for the binding. The activity is also present in extracts from mouse testis but not from liver. The phosphatase treatment revealed that Msbp-4 is phosphorylated and may have a regulatory function, because dephosphorylation affects the activity and specificity of the binding. Sequence preference is demonstrated by a competition experiment using single-base substitution mutants. Thus, the binding properties of Msbp-4 observed here lead to an implication that the protein-DNA complexes result in formation of a single-stranded DNA loop of the G-rich strand in the minisatellite which may enhance the ability of the minisatellite to undergo recombination.

Animals↗
PubMed1992

Stercoraceous perforation of the sigmoid colon: report of two cases.

Stercoraceous perforation of the sigmoid colon has rarely been reported in the literature. This lesion is assumed to be produced by the pressure from a hard scybalum resulting in a perforated ulcer with necrotic edges. Two cases of stercoraceous perforation of the sigmoid colon are presented in this paper. It is difficult to diagnose this lesion preoperatively, although ultrasonograms proved useful in showing the colon perforation. This lesion should always be suspected when a patient who has had chronic constipation presents with sudden severe abdominal pain. It is possible that this lesion is becoming more common as the mean age of the population increases and we stress the importance of immediate surgery and intensive care for improving the prognosis.

Aged↗
PubMed1992

Polymorphonuclear leukocyte function and serum opsonic activity in surgical patients.

Thirty-six patients who underwent major surgery were studied in order to clarify the perioperative changes in polymorpho - nuclear leukocyte (PMNL) function and serum opsonic activity. In patients without postoperative infection, the PMNL phagocytic-bactericidal capacity and plasma elastase levels significantly increased, while the serum opsonic index remarkably decreased just after surgery, however, all returned to the preoperative levels within 1 or 2 weeks. Conversely, in patients with postoperative infection, the PMNL bactericidal capacity and plasma elastase levels remained at high levels even after 1 or 2 weeks, while the PMNL phagocytic capacity and serum opsonic index substantially decreased after 2 weeks compared with the patients without postoperative infection. Plasma leukotriene B4, which is a potent chemo-attractant for PMNL, noticeably decreased in the patients with postoperative infection on the first postoperative day compared with that in the patients without postoperative infection. Our data suggests that the most important predisposing factors to postoperative infection may be a depressed PMNL phagocytic capacity and a lower serum opsonic activity after surgery, and that the increased PMNL bactericidal capacity and high plasma elastase levels during postoperative infection may contribute to the susceptibility to multiple organ failure.

Adult↗
PubMed1992

4-Borono-2-[18F]fluoro-D,L-phenylalanine: a possible tracer for melanoma diagnosis with PET.

The potential of 4-borono-2-[18F]fluoro-D,L-phenylalanine ([18F]FBPA), a flurodinated derivative of a target compound for boron neutron capture therapy, for melanoma imaging by positron emission tomography (PET) was studied using animal models. A high uptake of [18F]FBPA was found in murine B16 melanoma or in Greene's melanoma No. 179, a melanotic cell line in hamsters, for the first 6 h after injection. Whole body autoradiography using [18F]FBPA gave a clear image of the B16 tumor. The acid-insoluble 18F in the B16 increased to 27% by 6 h, and most of the free 18F was detected as [18F]FBPA in both B16 and plasma. In the hamster models, No. 179 showed a 1.7 times higher uptake than amelanotic Greene's melanoma No. 178 at 6 h post-injection, although both melanomas indicated similar metabolic activities when examined by a tracer uptake study using L-[14C]methionine, 2-deoxy-D-[14C]glucose and [3H]thymidine. [18F]FBPA may be a very promising PET tracer for melanoma imaging.

Animals↗
PubMed1992

Effects of human recombinant epidermal growth factor on the growth of MKN-28 human gastric carcinoma transplanted into nude mice.

The effects of human recombinant epidermal growth factor (EGF) on the growth of MKN-28 human gastric carcinoma, transplanted into nude mice were studied. Modulation of tissue cAMP and EGF receptor levels by EGF was also studied to reveal the mechanism of the growth inhibitory effects of EGF. EGF exhibited a dose-dependent growth inhibitory effect on MKN-28 human gastric carcinoma transplanted into nude mice. Local injection of 2 ng of EGF moderately inhibited the growth of MKN-28 gastric carcinoma, while injections of 20 ng, 200 ng and 2 micrograms of EGF significantly inhibited tumour growth. EGF decreased tissue cAMP levels in a dose-dependent manner within 24 h after EGF injection. On the other hand, EGF increased the EGF receptor levels up to two or three fold within 24 h after EGF injection. Conversely, the EGF receptor affinity for EGF decreased according to the increase in EGF receptor levels.

Aged↗
PubMed1992

c-Kit-kinase induces a cascade of protein tyrosine phosphorylation in normal human melanocytes in response to mast cell growth factor and stimulates mitogen-activated protein kinase but is down-regulated in melanomas.

The proto-oncogene c-Kit, a transmembrane receptor tyrosine kinase, is an important regulator of cell growth whose constitutively active oncogenic counterpart, v-kit, induces sarcomas in cats. Mutations in murine c-kit that reduce the receptor tyrosine kinase activity cause deficiencies in the migration and proliferation of melanoblasts, hematopoietic stem cells, and primordial germ cells. We therefore investigated whether c-Kit regulates normal human melanocyte proliferation and plays a role in melanomas. We show that normal human melanocytes respond to mast cell growth factor (MGF), the Kit-ligand that stimulates phosphorylation of tyrosyl residues in c-Kit and induces sequential phosphorylation of tyrosyl residues in several other proteins. One of the phosphorylated intermediates in the signal transduction pathway was identified as an early response kinase (mitogen-activated protein [MAP] kinase). Dephosphorylation of a prominent 180-kDa protein suggests that MGF also activates a phosphotyrosine phosphatase. In contrast, MGF did not induce proliferation, the cascade of protein phosphorylations, or MAP kinase activation in the majority of cells cultured from primary nodular and metastatic melanomas that grow independently of exogenous factors. In the five out of eight human melanoma lines expressing c-kit mRNAs, c-Kit was not constitutively activated. Therefore, although c-Kit-kinase is a potent growth regulator of normal human melanocytes, its activity is not positively associated with malignant transformation.

Cells, Cultured↗
PubMed1992

A unique in vivo assessment of 4-[10B]borono-L-phenylalanine in tumour tissues for boron neutron capture therapy of malignant melanomas using positron emission tomography and 4-borono-2-[18F]fluoro-L-phenylalanine.

A unique in vivo approach to assessing the concentrations of 4-[10B]borono-L-phenylalanine (L-BPA), a melanoma targeting compound for boron neutron capture therapy (BNCT), was investigated using L-BPA labelled with positron-emitting 18F (half-life = 110 min), i.e., 4-[10B]borono-2-[18F]fluoro-L-phenylalanine (L-[18F]FBPA). High melanoma uptake of L-[18F]FBPA was reduced slightly by competition with L-BPA in the two animal models of the murine B16 melanoma and the melanotic Greene's melanoma No. 179 in hamsters. In mice given L-[18F]FBPA and L-BPA, the concentrations of 10B in B16 estimated from 18F radioactivity were lower than those measured by inductively coupled plasma-atomic emission spectroscopy. Lower estimated values were dependent on the time after injection and on the loading dose of L-BPA. The estimated 10B concentrations for Green's melanomas were comparable to the measured values. Positron emission tomography (PET) using L-[18F]FBPA allowed Greene's melanomas to be clearly visualized. In conclusion, when L-[18F]FBPA is used as a probe for L-BPA in BNCT of malignant melanomas, the melanoma can be localized and the 10B concentrations in tissues can be assessed in vivo using 18F radioactivity by PET.

Animals↗
PubMed1992

Intracellular glutathione and its metabolizing enzyme activities in a metastatic variant melanoma cell line.

Levels of glutathione peroxidase (GSH-PX), glutathione-S-transferase (GST), gamma-glutamyl transpeptidase (gamma GTP) and glutathione reductase (GR) activities in the B16-F10 metastatic melanoma cell line are higher than those in non-metastatic B-16 murine melanoma cells. An inverse relationship was observed between the level of reduced glutathione (GSH) and metastatic capacity. Interferon (IFN), an antitumour and antimetastic agent, reduced the experimental metastatic capacity of B16-F10 cells while increasing the intracellular GSH content. This was associated with a fall in activity of GSH-metabolizing enzymes. These results suggest a correlation of intracellular GSH and its metabolizing enzymes with malignant transformation.

Animals↗
PubMed1992

Alpha-smooth muscle actin expression in tumor and stromal cells of benign and malignant human pigment cell tumors.

We examined the altered expression of alpha-smooth muscle actin (alpha-Sm) in human benign, pre-malignant, and malignant pigment cell tumors by immunohistochemical as well as biochemical (Western blot) analysis using anti-alpha-Sm monoclonal antibody (anti-alpha-Sm MoAb). The expression of alpha-Sm has been revealed immunohistochemically to be associated with mesodermal cells rather than with pigment cells. Western blot analysis using anti-alpha-Sm MoAb detected alpha-Sm expression as a 43-kD band in the extracts from normal papillary dermis, nevus cell nevus, and metastatic melanoma with stromal tissues, but not from primary melanoma with stromal tissues examined. The above findings of alpha-Sm expression by Western blot analysis were further characterized immunohistochemically in terms of the localization at the cellular level as follows. 1) In normal papillary dermis, pericytes encircling capillary vessels showed only positive staining with anti-alpha-Sm MoAb. 2) In nevus tissues, nevus cells were not shown to be positively stained, despite similar positivity of pericytes in normal papillary dermis. 3) In melanoma tissues, alpha-Sm expression of metastatic melanoma detected by Western blot analysis was found to be derived from fibroblasts with smooth-muscle differentiation (myofibroblasts), but not from melanoma cells. Such myofibroblastic stromal changes could not be found on primary melanoma tissue sections, which showed no reactivity in Western blot analysis. We conclude that the major sources of alpha-Sm in benign and pre-malignant pigment cell tumors are capillary pericytes, whereas alpha-Sm found in malignant melanoma tissue is primarily from melanoma-surrounding stromal fibroblasts that were changed to myofibroblasts by some cytokine factor(s), presumably secreted from melanoma cells.

Actins↗
PubMed1992

Malignant Langerhans cell tumour.

We report the case of a 49-year-old woman suffering from a malignant neoplasm of Langerhans cells (LC), documented by immunohistochemical and ultrastructural analysis, and review the literature to examine and characterize the clinical and laboratory features, therapy, and prognosis of malignant neoplasms of LC. Langerhans cell histiocytosis is now regarded as a disorder of immune regulation or an inflammatory process, rather than as a malignant neoplasm. Although LC share certain features in common with ordinary histiocytes or interdigitating dendritic cells, they also differ significantly from these cells in other respects. Therefore, we propose designating a malignant neoplasm of LC 'malignant Langerhans cell tumour' and that it should be considered as a separate entity from Langerhans cell histiocytosis or other malignant histiocytoses.

Antigens, CD↗
PubMed1992

[Successful preparation of mitoxantrone emulsion containing non-ionic contrast medium].

Mitoxantrone, a new anti-cancer agent, was successfully prepared for Lipiodol emulsion. The mixture of Mitoxantrone and non-ionic contrast medium, Omnipaque 300, was combined with Lipiodol at the ratio of 1:2. When the ratio of Mitoxantrone and Lipiodol was 1:4, microscopic study revealed stabilized water in oil emulsion, which could release the anti-cancer agent slowly. We applied it for a case of hepatocellular carcinoma with good result. Intra-arterial infusion of this emulsion might be considered effective for treatment of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1992

[A case of pulmonary atypical mycobacteriosis complicated with aplastic anemia, treated with surgical resection and postoperative sparfloxacin].

A few weeks after treatment with INH, RFP and SM, severe aplastic anemia developed in a 49-year-old man with pulmonary atypical mycobacteriosis due to M. kansasii. All drugs were discontinued immediately after bone marrow examination revealed severely hypoplastic marrow, but pancytopenia continued for several months. Although M. kansasii was sensitive to other drugs including CS and TH, these two drugs were also discontinued because of their respective psychiatric and hepatic adverse effects. Ofloxacin (OFLX), to which M. kansasii was sensitive, was administered without clinical improvement and complete resistance to OFLX developed after several months treatment. Right upper and middle lobectomy and S6 partial lobectomy was performed, and postoperative sparfloxacin (SPFX) administration resulted in cure of the disease. Drug sensitivity testing revealed that the organism had acquired resistance to OFLX, but was still sensitive to SPFX. Thus, SPFX appears to be an useful drug for the treatment of atypical mycobacteriosis.

Anemia, Aplastic↗
PubMed1992

Enterocolitis due to methicillin-resistant Staphylococcus aureus--report of two cases.

Two cases of postoperative enterocolitis due to methicillin-resistant Staphylococcus aureus (MRSA) after gastrectomy were experienced. Case 1: A 59-year-old male underwent subtotal gastrectomy for advanced gastric cancer. Diffuse peritonitis progressed after the first operation, so reoperation for drainage was required. Two days after the second operation, a profuse watery diarrhea developed. Case 2: A 46-year-old male underwent total gastrectomy for early gastric cancer. On the fourth postoperative day, frequent vomiting and cholera-like diarrhea started, followed by profound shock several hours later. Both cases were treated successfully by the administration of vancomycin. Stool cultures of both cases revealed MRSA and it had the same minimal inhibitory concentration, coagulase type and enterotoxin type, so that nosocomial infection was indicated.

Enterocolitis↗