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Biomedical subjects

M Sakaue

Publications and source records attributed to M Sakaue.

At least 37 records · Page 2Linked to original sources

A case of acute pancreatitis complicating Salmonella enteritis.

We report a case of acute pancreatitis complicating Salmonella enteritis. A 43-yr-old woman who was admitted to our department because of Salmonella enteritis developed clinical acute pancreatitis with laboratory and radiographic signs on the fourth hospital day. She was free from symptoms on the eighth hospital day, but her elevated serum amylase and lipase levels persisted for more than 2 m.o. In this case, clinical acute pancreatitis was a complication of bacterial enteritis caused by Salmonella enteritidis, and it was characterized by onset a few days after the onset of enteritis and by sustained elevation of serum pancreatic enzyme levels.

Acute Disease↗

Post-transcriptional regulation of MyD118 and GADD45 in human lung carcinoma cells during 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2- naphthalene carboxylic acid-induced apoptosis.

Recently, the novel synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (AHPN) has been shown to inhibit cell growth and induce apoptosis in several human carcinoma cell lines. To understand the mechanism of AHPN action, we identified, using the differential display method, several genes that are differentially regulated by AHPN. The sequence of one of these genes was highly homologous to mouse MyD118, a gene closely related to GADD45. Both of these genes have been reported to play a role in negative growth control and apoptosis. hMyD118 was expressed in a variety of tissues, including liver, skeletal muscle, kidney, pancreas, spleen, thymus, prostate, and peripheral blood leukocytes. The levels of both hMyD118 and GADD45 mRNA was rapidly increased in a number of carcinoma cell lines after treatment with AHPN. This increase was specific for AHPN because retinoic acid, a retinoic acid receptor-selective retinoid, and an retinoid X receptor-selective retinoid were ineffective. These results suggest that this action of AHPN involves a novel mechanism that is independent of the nuclear retinoid receptors. AHPN increases the half-life of hMyD118 and GADD45 mRNA by >9-fold, indicating that it causes an increase in the stability of these mRNAs. The caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoro-methylketone (ZVAD. fmk) had no effect on the induction of hMyD118, indicating that this increase occurred independently of caspase activation. Our study demonstrates that the inhibition of cell growth by AHPN is accompanied by an increase in hMyD118 and GADD45 mRNA, and that this enhancement is regulated at a post-transcriptional level. Our results support a role for MyD118 and GADD45 in the negative growth control by AHPN.

Amino Acid Sequence↗

Immunohistochemical and enzyme-histochemical study on the accessory olfactory bulb of the dog.

The accessory olfactory bulb (AOB) is a primary center of the vomeronasal system. In the dog, the position and morphology of the AOB remained vague for a long time. Recently, the morphological characteristics of the dog AOB were demonstrated by means of lectin-histochemical, histological, and immunohistochemical staining, although the distribution of each kind of neuron, especially granule cells, remains controversial in the dog AOB. In the present study, we examined the distribution of neuronal elements in the dog AOB by means of immunohistochemical and enzyme-histochemical staining. Horizontal paraffin or frozen sections of the dog AOB were immunostained with antisera against protein gene product 9.5 (PGP 9.5), brain nitric oxide synthase (NOS), glutamic acid decarboxylase (GAD), tyrosine hydroxylase (TH), substance P (SP), and vasoactive intestinal polypeptide (VIP) by avidin-biotin peroxidase complex method. In addition, frozen sections were stained enzyme-histochemically for NADPH-diaphorase. In the dog AOB, vomeronasal nerve fibers, glomeruli, and mitral/tufted cells were PGP 9.5-immunopositive. Mitral/tufted cells were observed in the glomerular layer (GL) and the neuronal cell layer (NCL). In the NCL, a small number of NOS-, GAD-, and SP-immunopositive and NADPH-diaphorase positive granule cells were observed. In the GL, GAD-, TH-, and VIP-immunopositive periglomerular cells were observed. In the GL and the NCL, TH-, and VIP-immunopositive short axon cells were also observed. In addition to these neurons, TH- and SP-immunopositive afferent fibers were observed in the GL and the NCL. We could distinctly demonstrate the distribution of neuronal elements in the dog AOB. Since only a small number of granule cells were present in the dog AOB, the dog AOB did not display such a well-developed GCL as observed in the other mammals.

Animals↗

Hematopoietic cytokine-dependent differentiation to eosinophils and neutrophils in a newly established acute promyelocytic leukemia cell line with t(15;17).

We recently established an acute promyelocytic leukemia (APL) cell line (HT93) that has the capacity to differentiate into neutrophils and eosinophils in response to all-trans retinoic acid (ATRA) and human hematopoietic cytokines. The cells had a myeloblastic morphology, were positive for surface CD33, CD34, and CD56, and showed the following karyotypes: 46, XY, t(1;12)(q25;p13), 2q+, t(4;6)(q12;q13), and t(15;17)(q22;q11). When the cells were cultured with ATRA, they showed nuclear segmentation and developed secondary granules consisting in part of neutrophils and eosinophils. In the presence of ATRA and granulocyte colony-stimulating factor (G-CSF), the cells showed polymorphonuclear neutrophil differentiation accompanied by expression of surface CD11b, CD15, CD10, positive activity for neutrophil alkaline phosphatase (NAP), and NAP mRNA expression. In cultures with ATRA and granulocyte-macrophage colony-stimulating factor (GM-CSF), IL (interleukin)-3, or IL-5, HT93 showed remarkable eosinophil maturation at day 8 as determined by luxol fast blue staining, in addition to expression of eosinophil peroxidase and major basic protein. These results indicate that HT93 is an APL cell line with the ability to differentiate into neutrophils and eosinophils, and that these lineages are dependent on the CSF added. HT 93 should prove to be a useful model in analyzing the effects of hematopoietic cytokines on proliferation, differentiation, and maturation of hematopoietic progenitors.

Alkaline Phosphatase↗

Interaction of Nck-associated protein 1 with activated GTP-binding protein Rac.

Bacterially expressed glutathione S-transferase fusion proteins containing Rac1 were used to identify binding proteins of this Rho family GTPase present in a bovine brain extract. Five proteins of 85, 110, 125, 140 and 170 kDa were detected, all of which were associated exclusively with guanosine 5'-[gamma-thio]triphosphate-bound Rac1, not with GDP-bound Rac1. The 85 and 110 kDa proteins were identified as the regulatory and catalytic subunits respectively of phosphatidylinositol 3-kinase. Several lines of evidence suggested that the 125 kDa protein is identical with Nck-associated protein 1 (Nap1). The mobilities of the 125 kDa protein and Nap1 on SDS/PAGE were indistinguishable, and the 125 kDa protein was depleted from brain extract by preincubation with the Src homology 3 domain of Nck to which Nap1 binds. Furthermore, antibodies to Nap1 reacted with the 125 kDa protein. Nap1 was co-immunoprecipitated with a constitutively active form of Rac expressed in Chinese hamster ovary cells. The observation that complex formation between activated Rac and PAK, but not that between Rac and Nap1, could be reproduced in vitro with recombinant proteins indicates that the interaction of Nap1 with Rac is indirect. The 140 kDa Rac-binding protein is a potential candidate for a link that connects Nap1 to Rac. The multimolecular complex comprising Rac, Nap1 and probably the 140 kDa protein might mediate some of the biological effects transmitted by the multipotent GTPase.

Animals↗

Novel analysis of minimal residual disease in leukemia with TCR beta rearrangement--detection of monoclonality by single strand conformation polymorphism and PCR using a clonotype primer of leukemic T cell receptor beta-chain RNA.

Several means of analyzing minimal residual disease (MRD) in leukemia involving the rearranged T cell receptor (TCR) gene have been described. We investigated MRD in leukemia with TCR beta rearrangement by examining TCR beta-chain RNA. A complementary DNA (cDNA) corresponding to the variable region of the TCR beta-chains originating from the peripheral blood or bone marrow from four patients was amplified. Single strand conformation polymorphism (SSCP) analysis of amplified cDNA showed that all four patients had monoclonal leukemia with TCR beta rearrangement; two patients had Vbeta2+ leukemia, another patient had Vbeta14+ leukemia and the other had Vbeta9+ leukemia. Flow cytometry supported this finding. Sequencing of the Vbeta2-complementarity determining region 3 (CDR3), Vbeta9-CDR3 and Vbeta14-CDR3 revealed monoclonality. To investigate MRD using TCR beta-chain RNA, cDNA from each patient was diluted with the cDNA of a healthy person and amplified using a specific CDR3 clonotype primer. A band in the ethidium bromide-stained agarose gel was detected from samples diluted 10,000-fold. SSCP analysis determined which V region gene was utilized in monoclonal leukemic cells. The leukemic cell specific TCR, determined in such a manner, may be a target for immunotherapy. Because the MRD of T cell malignancy can be easily examined once the CDR3 clonotype primer is made, this novel analysis is considered to be a useful method.

Adolescent↗

Primary familial polycythaemia associated with a novel point mutation in the erythropoietin receptor.

Primary familial and congenital polycythaemia (PFCP) is a rare disease characterized by congenital erythrocytosis inherited in an autosomal dominant fashion. Recently, mutations in the erythropoietin receptor (EpoR) have been identified in PFCP families. We describe a Japanese family with an autosomal dominant inheritance of PFCP. An in vitro colony assay demonstrated hypersensitivity of erythroid progenitors to erythropoietin (Epo) in affected family members. Sequence analysis of RT-PCR products amplified from the C-terminal region of EpoR transcripts in affected family members revealed that they were all heterozygous for C and T bases at position 5986, which suggested a genetic mutation (C to T) on one allele of EpoR. This mutation gave rise to a translation termination codon TAG at amino acid 435. Thus, the resulting EpoR is a truncated protein product lacking all 74 amino acids downstream of the mutation. To date, all genetic mutations affecting a family with PFCP, including this one, have been located in the cytoplasmic negative regulatory region of the EpoR. All mutations gave rise to truncated Epo receptors between Tyrosine 427 and Tyrosine 455. The phosphotyrosines in this region of EpoR have been demonstrated to be binding sites for SHP-1 phosphatase. Therefore PFCP is presumably brought about as a result of genetic mutations which cause the loss of the SHP-1 binding site in the cytoplasmic region of EpoR.

Base Sequence↗

Role of mitogen-activated protein kinase pathway in prostaglandin F2alpha-induced rat puerperal uterine contraction.

In this study, prostaglandin (PG) F2alpha was found to activate mitogen-activated protein (MAP) kinase and MAP kinase kinase (MEK) in cultured rat puerperal uterine myometrial cells. PGF2alpha stimulation also led to an increase in phosphorylation of raf-1, son of sevenless (SOS), and Shc. Furthermore, we examined the mechanism by which PGF2alpha induced MAP kinase phosphorylation. Both pertussis toxin (10 ng/ml), which inactivates Gi/Go proteins, and expression of a peptide derived from the carboxyl terminus of the beta-adrenergic receptor kinase 1 (betaARK1), which specifically blocks signaling mediated by the betagamma subunits of G proteins, blocked the PGF2alpha-induced activation of MAP kinase. Ritodrine (1 microM), which is known to relax uterine muscle contraction, attenuated PGF2alpha-induced tyrosine phosphorylation of MAP kinase. Moreover, to examine the role of MAP kinase pathway in uterine contraction, an inhibitor of MEK activity, PD098059, was used. Although MEK inhibitor had no effect on PGF2alpha-induced calcium mobilization, this inhibitor partially inhibited PGF2alpha-induced uterine contraction. These results provide evidence that PGF2alpha stimulates the MAP kinase signaling pathway in cultured rat puerperal uterine myometrial cells through Gbetagamma protein, suggesting that this new pathway may play an important role in the biological action of PGF2alpha on these cells.

Animals↗

Phosphoinositide 3-kinase is required for insulin-induced but not for growth hormone- or hyperosmolarity-induced glucose uptake in 3T3-L1 adipocytes.

The(1) regulatory mechanism of glucose uptake in 3T3-L1 adipocytes was investigated with the use of recombinant adenovirus vectors encoding various dominant negative proteins. Infection with a virus encoding a mutant regulatory subunit of phosphoinositide (PI) 3-kinase that does not bind the 110-kDa catalytic subunit (delta p85) inhibited the insulin-induced increase in PI 3-kinase activity co-precipitated by antibodies to phosphotyrosine and glucose uptake in a virus dose-dependent manner. Overexpression of a dominant negative RAS mutant in which Asp57 is replaced with tyrosine (RAS57Y) or of a dominant negative SOS mutant that lacks guanine nucleotide exchange activity (delta SOS) abolished the insulin-induced increase in mitogen-activated protein kinase activity, but had no effect on PI 3-kinase activity or glucose uptake. Although GH and hyperosmolarity attributable to 300 mM sorbitol each promoted glucose uptake and translocation of glucose transporter (GLUT)4 to an extent comparable to that of insulin, these stimuli triggered little or no association of PI 3-kinase activity with tyrosine-phosphorylated proteins. Overexpression of delta p85 or treatment of cells with wortmannin, an inhibitor of PI 3-kinase activity, had no effect on glucose uptake or translocation of GLUT4 stimulated by GH or hyperosmolarity. Moreover, overexpression of delta SOS or RAC17N also did not affect the increase in glucose uptake induced by these stimuli. A serine/threonine kinase Akt, a constitutively active mutant of which was previously shown to stimulate glucose uptake, is activated by insulin, GH, and hyperosmolarity to approximately 4-fold, approximately 2.1-fold, and approximately 2.3-fold over basal level, respectively. These results suggest that insulin-induced but neither GH- or hyperosmolarity-induced glucose uptake is PI 3-kinase-dependent, and neither RAS nor RAC is required for glucose uptake induced by these stimuli in 3T3-L1 adipocytes.

3T3 Cells↗

Molecular cloning and characterization of human bone morphogenic protein (BMP)-5 gene promoter.

The bone morphogenic proteins (BMPs) constitute a novel subfamily of the transforming growth factor type beta (TGF-beta) supergene family and play a critical role in modulating mesenchymal differentiation and inducing the processes of cartilage and bone formation. In this study we isolated the 5'-flanking region of the human BMP-5 gene. Nucleotide sequencing, primer extension, DNase I foot printing and functional analysis by transient expression showed that the cloned 1.5 kb promoter region contains two transcription start sites, a canonical TATA box (-17 approximately -12) and a number of consensus recognition sequences including GATA-1 (-582 approximately -576) and engrailed (-549 approximately -541).

Base Sequence↗

Molecular cloning of p125Nap1, a protein that associates with an SH3 domain of Nck.

Binding proteins to the Src homology 3 (SH3) domains of Nck were screened by the use of glutathione S-transferase fusion proteins. Two proteins of 140 and 125 kDa were detected, both of which associated preferentially with the first SH3 domain of Nck. The 125-kDa protein, designated as Nap1 for Nck-associated protein 1, was purified and the corresponding rat cDNA was isolated. The predicted amino acid sequence revealed that p125Nap1 does not contain any known functional motif but shows sequence homology to Hem family gene. Using specific antibodies, p125Nap1 was shown to associate with Nck both in vitro and in intact cells. Further characterization of p125Nap1 may clarify the protein-protein interaction in the downstream signaling of Nck.

Adaptor Proteins, Signal Transducing↗

Adenovirus-mediated transfer of HPV 16 E6/E7 antisense RNA to human cervical cancer cells.

To explore the potential of an adenoviral antisense RNA transcript for gene therapy of cervical cancer, we introduced the antisense RNA transcript of E6 and E7 genes of human papillomavirus (HPV) 16 into cervical cancer cells harboring HPV 16 via a recombinant adenoviral vector, Ad5CMV-HPV 16 AS and analyzed the effects of expression of these genes on cell growth and tumor growth. Ad5CMV-HPV 16 AS contains the cytomegalovirus-promoter, E6 and E7 genes of HPV 16 in antisense orientation, and the SV40 polyadenylation signal in a mini-gene cassette, which is inserted into the E1-deleted region of modified adenovirus 5. The entire E6/E7 region of HPV 16 was amplified by polymerase chain reaction (PCR) before cloning into the mini-gene cassette. By reverse transcriptase-PCR, HPV 16 E6/E7 antisense RNA was detected in SiHa cells infected with Ad5CMV-HPV 16 AS. The growth of the Ad5CMV-HPV 16 AS-infected cells was greatly suppressed, as evidenced by a decrease in cell count. The growth inhibitory effect of Ad5CMV-HPV 16 AS was significantly enhanced by an adenoviral p53 construct, Ad5CMV-p53. In an ex vivo study in nude mice, tumorigenicity was completely inhibited in mice injected with Ad5CMV-HPV 16 AS-infected SiHa cells. These data suggest that transfection of cervical cancer cells with HPV 16 E6/E7 antisense RNA in a form such as Ad5CMV-HPV 16 AS is a potential novel approach to the therapy of HPV 16-positive cervical cancer.

Adenoviridae↗

Decreased expression of the DCC gene in human breast carcinoma.

Inactivation of the "deleted in colon cancer" (DCC) gene on chromosome 18 is known to be associated with the tumorigenesis and metastasis of colorectal cancer. In the present study, we investigated the expression of DCC and the c-erbB-2 product in surgical specimens from 45 patients with breast cancer by immunohistochemical staining, and found the expression of DCC to be decreased in 23 (51%) tumors. In 8 years of follow-up, 11 of 22 (50%) patients with DCC-positive staining tumors, and 17 of 23 (74%) patients with DCC-negative tumors developed recurrence. The stratified analysis, according to the status of axillary lymph node metastasis, showed the same tendency. Overexpression of erbB-2 was detected in 13 (29%) of the 45 breast cancer specimens, but there were no differences in the relapse rate between patients with erbB-2 positive and those with erbB-2 negative tumors. Although the individual alteration of DCC or erbB-2 did not possess independent prognostic significance for the prediction of recurrence, patients with tumors having the double alteration of DCC-negative and erbB-2-positive showed adverse relapse-free survival (0.025 < P < 0.05). These findings suggest that a decrease in DCC expression and erbB-2 overexpression may influence the progression of breast carcinoma.

Adult↗

Modulation of thermogenic response to parenteral amino acid infusion in surgical stress.

Thermogenic response to parenteral infusion of amino acid mixtures in rats undergoing surgical stress was investigated with the aid of a small animal indirect calorimeter. Male Wistar rats (n = 12) were laparotomized and received intestinal abrasion along with construction of a parenteral route. After 48 h, nutrient-induced thermogenesis (NIT) produced by amino acid mixtures was examined and compared with that of control rats (n = 12) without surgical stress. The NIT values of the leucine-enriched solution were greater than those of the control solution in both rats with and without surgical stress. The NIT generated by the leucine-enriched solution in rats with surgical stress was significantly higher than that in rats without. NIT values for 10 different kinds of single amino acid solutions with identical concentrations was then examined in 60 rats. The NIT values of the leucine and the glycine solutions were relatively higher than those of other solutions. However, when puromycin was injected intraperitoneally into 12 rats just before measurement of the NIT in response to amino acid mixtures, no significant differences were found in NIT values between the mixtures. In summary, surgical stress increased the thermogenic response to the leucine-enriched solution, indicating that utilization of leucine may be augmented under surgical stress. In fact, leucine itself may be a thermogenic amino acid. Inhibition of protein synthesis prevented the increase in thermogenic response induced by the leucine-enriched solution. We conclude that thermogenic responses to parenteral amino acid mixtures may differ depending not only upon the compositions of amino acids but also upon the host conditions.

Amino Acids↗

Urokinase-type plasminogen activator gene regulation by polyomavirus middle-T antigen.

Expression of polyomavirus middle-T antigen (middle-T) is involved in the formation of various tumors in vivo, e.g. hemangiomas and mammary gland tumors. Several genes have been shown to be activated in middle-T-expressing cells, but the underlying mechanisms have only been partially elucidated. Among the genes regulated by middle-T, the urokinase-type plasminogen activator (uPA) gene seems to be of primary importance for the development of the transformed phenotype. We have found that the uPA gene is highly expressed in eEnd2 cells derived from a hemangioma expressing middle-T. NIH3T3 cells show negligible levels of uPA mRNA but its expression was highly induced by infecting with a middle-T-expressing retrovirus. Middle-T did not affect uPA mRNA stability. Transient cotransfection experiments using a uPA-receptor gene construct and a middle-T expression vector showed that high uPA mRNA levels are due to increased uPA promoter activity. Analyses of various signaling molecules by transient cotransfection assays and in vitro kinase assays established that a signaling pathway involving c-Src, SOS, Ras, Raf-1 and ERK is activated by middle-T in NIH3T3 cells, resulting in the activation of the uPA gene promoter via PEA3/AP1 elements. In contrast, in eEND2 cells uPA gene induction is only partially dependent on this pathway, suggesting the involvement of additional signaling molecules in endothelial cells.

3T3 Cells↗

Receptor-tyrosine-kinase- and G beta gamma-mediated MAP kinase activation by a common signalling pathway.

Mitogen-activated protein (MAP) kinases mediate the phosphorylation and activation of nuclear transcription factors that regulate cell growth. MAP kinase activation may result from stimulation of either tyrosine-kinase (RTK) receptors, which possess intrinsic tyrosine kinase activity, or G-protein-coupled receptors (GPCR). RTK-mediated mitogenic signalling involves a series of SH2- and SH3-dependent protein-protein interactions between tyrosine-phosphorylated receptor, Shc, Grb2 and Sos, resulting in Ras-dependent MAP kinase activation. The beta gamma subunits of heterotrimeric G proteins (G beta gamma) also mediate Ras-dependent MAP kinase activation by an as-yet unknown mechanism. Here we demonstrate that activation of MAP kinase by Gi-coupled receptors is preceded by the G beta gamma-mediated tyrosine phosphorylation of Shc, leading to an increased functional association between Shc, Grb2 and Sos. Moreover, disruption of the Shc-Grb2-Sos complex blocks G beta gamma-mediated MAP kinase activation, indicating that G beta gamma does not mediate MAP kinase activation by a direct interaction with Sos. These results indicate that G beta gamma-mediated MAP kinase activation is initiated by a tyrosine phosphorylation event and proceeds by a pathway common to both GPCRs and RTKs.

Adaptor Proteins, Signal Transducing↗

A dominant-negative mutant of mSOS1 inhibits insulin-induced Ras activation and reveals Ras-dependent and -independent insulin signaling pathways.

The role of the Grb2-SOS complex in insulin signal transduction was investigated with a deletion mutant of mSOS1 that lacks the guanine nucleotide exchange domain of the wild-type protein. Cells over-expressing either wild-type (CHO-IR/SOS cells) or mutant (CHO-IR/delta SOS cells) mSOS1 were established by transfection of Chinese hamster ovary cells that express human insulin receptors (CHO-IR cells) with the appropriate expression plasmid. The mutant mSOS1 protein did not contain the guanine nucleotide exchange activity in vitro and associated with Grb2 both in vivo and in vitro. In both CHO-IR and CHO-IR/SOS cells, insulin rapidly stimulated the formation of GTP-bound Ras and the phosphorylation of mitogen-activated protein (MAP) kinase; both these effects of insulin were markedly inhibited in CHO-IR/delta SOS cells. Insulin-induced glycogen synthase and 70-kDa S6 kinase activities were not affected by expression of either wild-type or mutant mSOS1. These results show that the mutant mSOS1 acts in a dominant-negative manner and suggest that the Grb2-SOS complex mediates, at least in part, insulin-induced activation of Ras in intact cells. The data also indicate that Ras activation is not required for insulin-induced stimulation of glycogen synthase and 70-kDa S6 kinase.

Animals↗

Effects of cell density and conditioned medium on alpha 2A adrenergic receptor density and messenger RNA abundance in HT-29 cells.

We have examined the relationship between cell density and alpha 2A adrenergic receptor number and mRNA in HT-29 cells. alpha 2A receptors increased with increasing cell density from 75 +/- 25 to 400 +/- 73 fmol/mg protein; alpha 2A receptor mRNA also increased about 4 fold with no change in abundance of beta-actin mRNA. We prepared serum-free conditioned medium (SFCM) from confluent dishes of HT-29 cells and applied this SFCM to cells seeded at low density. A 4.7-fold increase in receptor number was observed in HT-29 cells cultured in SFCM for 3 days and alpha 2A receptor mRNA level increased about 3-fold after 24 h. Dialysis of SFCM against fresh growth medium did not abolish these effects. These results suggest that a substance secreted from HT-29 cells regulates expression of alpha 2A receptors.

Cell Count↗