Biomedical subjects

N Ueno

Publications and source records attributed to N Ueno.

At least 19 recordsLinked to original sources

PubMed1995

Induction of apoptotic cell death by pancreatitis-associated ascitic fluid in Madin-Darby canine kidney cells.

We investigated the cytotoxicity on Madin-Darby canine kidney (MDCK) cells of pancreatitis-associated ascitic fluid (PAAF) collected from rats with experimental necrotizing pancreatitis. PAAF reduced viability of MDCK cells in a time- and dose-dependent manner. We detected DNA fragmentation on the PAAF-treated MDCK cells, indicating that the cytocidal action of PAAF is via apoptosis. From the results obtained, we conclude that PAAF contains factor(s) inducing apoptosis on MDCK cells, and we assume that apoptotic cell death is involved in the mechanism of organ failure in acute pancreatitis.

Acute Disease↗

PubMed1995

Developmental and differential regulations in gene expression of Xenopus pleiotrophic factors-alpha and -beta.

Using conserved nucleotide sequences in mammalian osteoblast specific factor-1 (OSF-1) coding regions, we isolated two kinds of cDNA clones from the Xenopus brain library. The encoded proteins, named Xenopus pleiotrophic factors (X-PTFs)-alpha and -beta, were 65 and 87% homologous to human midkine and OSF-1, respectively. In the adult frog, X-ptf-alpha was expressed in the ovary, brain, eye, bone, heart and lung, whereas X-ptf-beta was expressed in the brain, eye and bone. By in situ hybridization of the tailbud embryo, X-ptf-alpha mRNA was detected rather broadly in the head/tail regions including the central nervous system (CNS), whereas X-ptf-beta mRNA was restricted to the CNS, particularly in the hind-brain. During embryogenesis, X-ptf-alpha mRNA was detected in the one-cell stage embryo, whereas only zygotic expression was observed in X-ptf-beta. X-ptf-beta mRNAs contained approximately 79 bp tandem repeats in the 3'-untranslated region, complementary to those found in retinoic acid cellular receptor mRNA and in the sense strand of short interspersed repeat transcripts in X. laevis.

Aging↗

PubMed1995

Involvement of the MAP kinase cascade in Xenopus mesoderm induction.

Mitogen-activated protein kinase (MAPK) is activated by MAPK kinase (MAPKK) in a variety of signaling pathways. This kinase cascade has been shown to function in cell proliferation and differentiation, but its role in early vertebrate development remains to be investigated. During early vertebrate embryogenesis, the induction and patterning of mesoderm are thought to be determined by signals from intercellular factors such as members of the fibroblast growth factor (FGF) family and members of the transforming growth factor-beta family. Here we show that the microinjection of either mRNA encoding a constitutively active mutant of MAPKK or mRNA encoding a constitutively active form of STE11, a MAPKK kinase, leads to the induction of mesoderm in ectodermal explants from Xenopus embryos. Moreover, the expression of MAPK phosphatase-1 (MKP-1, also called CL100) blocks the growth factor-stimulated mesoderm induction. Furthermore, injection of CL100 mRNA into two-cell stage embryos causes severe defects in gastrulation and posterior development. The effects induced by CL100 can be rescued by co-injection of wild-type MAPK mRNA. Thus, the MAPK cascade may play a crucial role in early vertebrate embryogenesis, especially during mesoderm induction.

Animals↗

PubMed1995

Molecular cloning and functional analysis of a new activin beta subunit: a dorsal mesoderm-inducing activity in Xenopus.

A cDNA that encodes a new member of the TGF-beta superfamily most similar to activin beta A, beta B, and recently reported beta C has been isolated from Xenopus laevis. Expression of the gene in early embryos suggested its biological importance in Xenopus embryogenesis. Microinjection of a synthetic mRNA transcribed from the cDNA into ventral blastomeres of early Xenopus embryo led to the formation of secondary body axis. Mesodermal marker genes were induced in isolated animal cap by a similar mRNA injection. These results demonstrate that the gene encodes a new member of activin subfamily whose function is closely related to mesoderm induction.

Activins↗

PubMed1995

Efficient expression of a heterodimer of bone morphogenetic protein subunits using a baculovirus expression system.

Recombinant baculoviruses as expression vectors for Xenopus bone morphogenetic protein (xBMP)-2, 4 and 7 were generated. The conditioned medium of insect cells infected with the virus for xBMP-2 or 4 showed strong alkaline phosphatase-inducing activity in a mouse osteoblastic cell line, MC3T3-E1, although a large portion of the activity remained in the infected cells. In contrast, xBMP-7 was preferentially secreted into the medium, but had only weak activity. Conditioned media following simultaneous inoculation with the viruses for xBMP-7 and for xBMP-2 or 4 showed a remarkably increased level of activity. The increased activity was clearly separated from other peaks derived from single infection on a cation-exchange column and was found to arise from the disulfide-linked heterodimer consisting of xBMP-4 and 7 subunits by immunoblot analysis. The heterodimer also augmented osteocalcin production and parathyroid hormone-sensitivity more strongly than the homodimers. These results suggest that our expression system provides a convenient source of heterodimeric BMP with high osteogenic differentiation-inducing activity.

3T3 Cells↗

PubMed1995

Genomic organization and chromosomal location of the mouse type I BMP-2/4 receptor.

We have characterized the structure of a mouse bone morphogenetic protein (BMP) type I receptor gene that can bind both BMP-2 and BMP-4. The mouse BMP-2/4 receptor gene is encoded by 11 exons and spans approximately 38-kb. Most of the intron/exon boundaries are not conserved compared to the kinase domain of the related, activin type II receptor. In addition, whereas the activin type II receptor gene contains large introns (> 40 kb), the largest intron of the BMP-2/4 receptor gene is only 6.4-kb. The BMP-2/4 receptor gene (Bmpr) was mapped to mouse chromosome 14. Bmpr is closely linked to Rbp3 in the region containing pugnose, a mutation that alters bone development. Knowledge of the genomic structure of Bmpr provides important information to create Bmpr-deficient mice.

Amino Acid Sequence↗

PubMed1995

BMP-4 regulates the dorsal-ventral differences in FGF/MAPKK-mediated mesoderm induction in Xenopus.

Recent studies on Xenopus development have revealed an increasingly complex array of inductive, prepatterning, and competence signals that are necessary for proper mesoderm formation. In this study, we establish that fibroblast growth factor (FGF) signals through mitogen-activated protein kinase kinase (MAPKK) to induce mesodermal gene expression. We demonstrate that a partially activated form of MAPKK restores expression of the mesodermal genes Xcad-3 and Xbra, eliminated by the dominant-negative FGF receptor (delta FGFR). Similar to the results reported earlier with delta FGFR, expression of a dominant-negative form of MAPKK (MAPKKD) preferentially eliminates the dorsal expression of Xcad-3 and Xbra. We tested whether the regional localization of bone morphogenetic protein-4 (BMP-4) could explain why both MAPKKD and delta FGFR eliminate the dorsal and not the ventral expression of Xcad-3 and Xbra. We show that ectopic expression of BMP-4 is sufficient to maintain the dorsal expression of Xcad-3 and Xbra in embryos containing delta FGFR and that expression of a dominant-negative BMP receptor reduces the dorsal-ventral differences in delta FGFR embryos. These results indicate that regional localization of BMP-4 is responsible for the dorsal-ventral asymmetry in FGF/MAPKK-mediated mesoderm induction.

Animals↗

PubMed1995

Localized BMP-4 mediates dorsal/ventral patterning in the early Xenopus embryo.

Mesoderm is initially induced in the amphibian embryo by events that occur in the early cleavage stages prior to the midblastula transition (MBT) and morphogenesis. These inductive interactions establish the mesoderm at the equator and create a distinction between the dorsal and the ventral regions. After the MBT, zygotic factors pattern the mesoderm and induce the neuroectoderm on the dorsal side of the embryo. Most previous studies have focused on the effects of signals originating in the dorsal mesoderm. We show that BMP-4 transcripts are localized to the ventral side of the gastrula embryo and provide evidence that localized expression of BMP-4 is important for regulating the expression of mesodermal and neural genes. We show that ectopic expression of BMP-4 inhibits the formation of dorsal and lateral mesoderm and reduces the size of the neural plate. Elimination of BMP-4 signaling with a dominant-negative BMP receptor expands the lateral mesoderm and neural plate without expanding the expression of genes along the dorsal midline. These results suggest that BMP-4 may act to oppose the action of dorsalizing signals and neural-inducing signals that originate in the dorsal organizer region. We suggest that BMP-4 may have an analogous role to the Drosophila gene, dpp, in dorsal/ventral pattern formation.

Animals↗

PubMed1995

Serum-induced collagen gel contraction.

PURPOSE: To understand the molecular events underlying disease-related vitreous gel contraction, the effect of serum components on collagen was investigated. METHODS: Bovine vitreous or dermal collagen was incubated with a mixture of transglutaminase (TG; factor XIIIa) and fibronectin (FN), and the biochemical changes of collagen were monitored by gel electrophoresis. In addition, serum-induced changes in the volume of the collagen gel were monitored. RESULTS: Gel electrophoresis revealed a new high-molecular-weight band (M(r) 240,000) presumably due to intermolecular cross-links of collagen peptides and FN. The serum components also were shown to cause a significant decrease in the volume of the collagen gel. CONCLUSION. Collagen gel contraction could be attributed to the collagen-FN-collagen cross-links catalyzed by TG.

Animals↗

PubMed1995

Headache associated with aseptic meningeal reaction as clinical onset of Fabry's disease.

This report concerns an 18-year-old boy who is hemizygote for Fabry's disease. Varying degrees of nonpulsating headache crises, lasting from a few hours to several days, began when he was 16 years of age. Painful crises in the extremities, characteristic of Fabry's disease, were not present. Although only occasional, he had several episodes of throbbing headache with vomiting without aura. The meningeal signs were equivocal, although the patient had noninfectious pleocytosis, intracranial hypertension, delayed radioisotope clearance on cisternography, and multiple old cerebral infarcts. Nonsteroidal anti-inflammatory drugs, antidepressants, carbamazepine, and glycerol were of no benefit for his headache. Although its mode of action remains obscure, prednisolone was effective for treating the headache and the aseptic meningeal reaction.

Adolescent↗

PubMed1995

[Inhibitory effects of hydroquinone-alpha-glucoside on melanin synthesis].

Inhibitory effects of hydroquinone-alpha-glucoside (HQ-alpha-G) on the melanogenesis were investigated and compared with those of arbutin. The levels of inhibitory effects of HQ-alpha-G and arbutin on the tyrosinase activity were nearly the same. Inhibitory effects of both compounds on the melanogenesis, were studied using cultured B16 melanoma cells, and HQ-alpha-G was also found to have a similar effect to that of arbutin without inhibiting cell growth. In this experiment, while HQ-alpha-G hardly inhibited cell growth at 1 mM, arbutin inhibit it significantly at the same concentration. From these results it is suggested that HQ-alpha-G as well as arbutin inhibited the melanogenesis by affecting tyrosinase rather than by killing melanocytes. Furthermore, the melanogenesis of guinea-pigs with brown hair was reduced to about 80% by applying them each compound. The great differences in toxicity to normal human keratinocyte were not recognized between these two glucosides. It is, therefore, considered that HQ-alpha-G is an effective and safe ingredient for cosmetics.

Animals↗

PubMed1995

Preoperative staging of extrahepatic bile duct cancer with intraductal ultrasonography.

OBJECTIVE: To evaluate the tumor extension of extrahepatic bile duct cancer by means of intraductal ultrasonography (IDUS). METHODS: IDUS preoperatively assessed the tumor extensions in 25 patients with extrahepatic bile duct cancer. The diagnostic accuracy of IDUS was investigated by comparison with other diagnostic imaging modalities in all cases and with histopathological findings of resected specimens in 18 cases. RESULTS: IDUS proved useful in assessing the extension of cancer invasion to the pancreas parenchyma, portal vein, and right hepatic artery. The limitation of the degree of accuracy, based on the group staging criteria, was 68%. IDUS could not assess tumor invasion to the perimuscular loose connective tissue. Therefore, it could not distinguish stage II from stage I. IDUS could not sufficiently assess epicholedochal lymph node metastases (differential diagnosis between stages II and III) and could not demonstrate distant metastases (differential diagnosis between stages IVA and IVB) because of the inevitable attenuation of the echo itself. IDUS could assess cases of stage IVA correctly in 8/8 (100%) cases. The combination of PTC/ERC and IDUS could assess the horizontal extension correctly in 13/18 (72%) cases. The combination of PTC/ERC, percutaneous transhepatic cholangioscopy (PTCS), and IDUS assessed the horizontal extension in 14/15 (93%) cases. CONCLUSION: 1) IDUS, with a high-frequency probe, was very useful for assessing tumor infiltration in the hepatoduodenal ligament. 2) IDUS could not assess tumor extension outside of the hepatoduodenal ligament, but conventional ultrasonography and angiography could compensate for it. 3) The combination of PTC/ERC, PTCS, and IDUS could assess horizontal extension correctly.

Aged↗

PubMed1994

Cloning of an isoform of mouse TGF-beta type II receptor gene.

A variant of transforming growth factor-beta type II receptor (TGF-beta RII) cDNA was isolated from a mouse brain cDNA library. The predicted receptor is identical to previously reported mouse TGF-beta RII except that the isoform has an insertion sequence of 25 amino acids in the predicted ligand-binding domain. By the use of reverse transcription-polymerase chain reaction (RT-PCR), transcripts for both isoforms were detected in all tissues and developing embryos examined. The isoform transiently expressed in COS cells showed a similar ligand-binding specificity to authentic TGF-beta RII. These results suggest that the mouse TGF-beta RII gene generates multiple isoforms, possibly by alternative splicing, as reported for activin type IIB receptor; and an isoform which has the extra sequence in the ligand-binding domain is also involved in the TGF-beta signal transduction.

Alternative Splicing↗

PubMed1994

A truncated bone morphogenetic protein receptor affects dorsal-ventral patterning in the early Xenopus embryo.

Bone morphogenetic proteins (BMPs), which are members of the transforming growth factor beta (TGF-beta) superfamily, have been implicated in bone formation and the regulation of early development. To better understand the roles of BMPs in Xenopus laevis embryogenesis, we have cloned a cDNA coding for a serine/threonine kinase receptor that binds BMP-2 and BMP-4. To analyze its function, we attempted to block the BMP signaling pathway in Xenopus embryos by using a dominant-negative mutant of the BMP receptor. When the mutant receptor lacking the putative serine/threonine kinase domain was expressed in ventral blastomeres of Xenopus embryos, these blastomeres were respecified to dorsal mesoderm, eventually resulting in the formation of a secondary body axis. These findings suggest that endogenous BMP-2 and BMP-4 are involved in the dorsal-ventral specification in the embryo and that ventral fate requires induction rather than resulting from an absence of dorsal specification.

Amino Acid Sequence↗

PubMed1994

A truncated bone morphogenetic protein 4 receptor alters the fate of ventral mesoderm to dorsal mesoderm: roles of animal pole tissue in the development of ventral mesoderm.

The biological effects of endogenous bone morphogenetic protein 4 (BMP-4), a member of the transforming growth factor beta family, on embryonic development of Xenopus laevis were investigated by using a functionally defective mutant of the BMP-4 receptor (delta mTFR11), which blocks the BMP signaling pathway. Injection of delta mTFR11 RNA into either the animal pole area or ventral marginal cells at the two-cell stage induced a dorsal phenotype in the explant of ventral mesoderm with animal pole tissue from stage 10+ embryo, even though the normal fate of this explant is a "mesenchymal ball" containing blood cells. These explants with the dorsal phenotype contained muscle, neural tissue, eye capsule, and cement gland. Northern blot analysis showed an increase of cardiac alpha-actin mRNA and a decrease of T alpha-globin mRNA expression, providing further evidence of a conversion from ventral to dorsal phenotype. Although injection of delta mTFR11 RNA did not induce mesoderm in an animal cap culture, the same tissue injected with delta mTFR11 RNA can alter the differentiation fate of uninjected ventral mesodermal explant from ventral to dorsal type, suggesting specific interaction of animal pole tissue and prospective ventral mesoderm in vivo.

Animals↗

PubMed1994

Cloning of a Drosophila melanogaster homologue of the mouse type-I bone morphogenetic proteins-2/-4 receptor: a potential decapentaplegic receptor.

The Drosophila melanogaster (Dm) decapentaplegic (dpp) gene product plays an essential role during several stages of Dm development. The DPP protein is a member of the transforming growth factor-beta (TGF-beta) superfamily and an orthologue of mammalian bone morphogenetic proteins (BMP-2 and -4). Recently, a cDNA clone encoding the mouse Ser/Thr kinase receptor specific for BMP-2/-4 (mTFR11) was isolated. Here, we describe the deduced primary structure, the cytogenetic position and expression pattern of the Dm homologue of mTFR11 (DTFR), a putative DPP receptor. The cytogenetic position of the Dm dtfr gene was mapped to 25D. DTFR has striking homology to mTFR11, especially in the cytoplasmic domain (approx. 63%), including a Ser + Gly-rich box that is characteristic of type-I receptors for the TGF-beta superfamily. Although the amino acid (aa) sequence of the extracellular domain is less conserved than that of the cytoplasmic domain, the extracellular domains of these two molecules were more homologous (approx. 27%) to each other than any other receptors for the TGF-beta superfamily. The spacing of Cys residues in the extracellular domain, which is considered crucial to ligand specificity, is highly conserved in these two receptors. During Dm embryonic development, its expression pattern changes in a dynamic fashion with high levels of expression in mesoderm and midgut, with some relation to dpp mutant phenotypes.

Amino Acid Sequence↗

PubMed1994

Comparison of kinetic properties between MSS4 and Rab3A GRF GDP/GTP exchange proteins.

The kinetic properties of MSS4 are studied in comparison with those of Rab3A GRF. MSS4 stimulates the dissociation of [3H]GDP from the lipid-modified and lipid-unmodified forms of Rab3A to the same extent, although Rab3A GRF is more effective on the lipid-modified form than on the lipid-unmodified form. Both MSS4 and Rab3A GRF are inactive on other Rab/Sec/Ypt family members including at least Rab2, Rab5, and Rab11. Rab GDI inhibits the MSS4 and Rab3A GRF effects on the lipid-modified form of Rab3A, but the doses of Rab GDI necessary for this inhibitory effect on Rab3A GRF are lower than those on MSS4. Moreover, Rab GDI slightly inhibits the Rab3A GRF effect on the lipid-unmodified form of Rab3A, but does not affect the MSS4 effect on the lipid-unmodified form of Rab3A. These results suggest that MSS4 and Rab3A GRF are different GDP/GTP exchange proteins for Rab3A.

GTP-Binding Proteins↗

PubMed1994

Localization of thymosin beta 4 to the neural tissues during the development of Xenopus laevis, as studied by in situ hybridization and immunohistochemistry.

Thymosin beta 4, a polypeptide of 5 kDa, is known to have capacity to regulate actin polymerization by binding to an actin monomer. Distribution of Xenopus laevis thymosin beta 4 (XT beta 4) in the developing Xenopus larva was examined by means of in situ hybridization and immunohistochemistry. Analysis with in situ hybridization revealed that XT beta 4 mRNA becomes gradually localized to the neural tissues, notochord and inner epidermis during neurula stages. Intense accumulation of XT beta 4 mRNA was observed in the ganglions of cranial nerves and in the dorsal region of the spinal cord from stage 26 and onwards. XT beta 4 immunoreactivity (XTI) was observed in larvas at all developmental stages later than stage 26, tail bud embryo. Immunoreactivity was initially distributed to the ganglion of cranial nerve V and Rohon-Beard cells. As the development progressed, the XTI appeared in other neuronal groups. By late tadpole stages (stages 42-47) the XTI was found in the pineal body, oculomotor and trochlear motoneurons of the midbrain, various neurons in the rhombencephalon, ganglions of cranial nerves V, VII/VIII and IX/X. In the spinal cord the XTI was observed in Rohon-Beard cells, dorsal root ganglion cells, motoneurons and other spinal cord neurons. Immunoreactivity was seen in both cell bodies and axons of the neurons. These findings suggest that thymosin beta 4 plays a role in the development of neurons, especially of sensory neurons.

Amino Acid Sequence↗