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Biomedical subjects

H Matsuo

Publications and source records attributed to H Matsuo.

At least 307 records · Page 17Linked to original sources
PubMed1996

Uroguanylin gene expression in the alimentary tract and extra-gastrointestinal tissues.

Uroguanylin, a member of the guanylin peptide family, is a novel peptide regulator for intestinal salt and water transport. A cDNA encoding a precursor for rat uroguanylin was cloned from a rat jejunum cDNA library and sequenced. The precursor was 106 amino acids long and included a 21 residue putative signal peptide at the N-terminus. Rat uroguanylin consisted of 15 amino acids similar to, but distinct from human uroguanylin; the C-terminal leucine residue was deleted and 3 residues were substituted compared to those in the human peptide. Synthetic rat uroguanylin-15 dose-dependently increased the cyclic GMP level in cultured T84 cells. RNA blot analysis showed that rat uroguanylin mRNA is expressed not only in the gastrointestinal tract but also in the lung, pancreas and kidney. Evidence for uroguanylin expression in extra-gastrointestinal tissues indicates the possible existence of a novel system for water and electrolyte homeostasis, and a more global effect of uroguanylin on epithelial cell function.

Amino Acid Sequence↗
PubMed1996

Adenosine 3',5'-cyclic monophosphate mimics the inhibitory effect of high glucose on MAP kinase phosphorylation in rat mesangial cells.

Alteration in mesangial cell function induced by high glucose levels is implicated in the development of diabetic nephropathy. The aim of this study was to investigate the mechanism by which high glucose attenuates mesangial cell proliferation. Thymidine incorporation in cultured mesangial cells decreased in the presence of high glucose concentrations in a dose dependent manner, with the maximum decrease of 25% occurring at a glucose concentration of 55.5 mM. Phosphorylation of mitogen-activated protein (MAP) kinase was abolished when the cells were treated with 55.5 mM glucose compared with 11.1 mM glucose. The concentration of intracellular cAMP doubled in the presence of 55.5 mM glucose. The addition of 8Br-cAMP (1.0 mM) to the culture media containing 11.1 mM glucose decreased thymidine incorporation by 34%, similar to the effect of high glucose. In order to clarify the contribution of protein kinase A (PKA) to the MAP kinase cascade, we used PKA inhibitor (H-8). The addition of H-8(10 microM) recovered MAP kinase phosphorylation in the presence of 55.5 mM glucose. Our data indicated that the inhibition of this mitogenic pathway mediated by activation of PKA, which is probably induced by high glucose levels, may play an important role in the perturbation of mesangial cells.

Animals↗
PubMed1996

cDNA cloning and genomic structure of human bone morphogenetic protein-3B (BMP-3b).

BMP-3b (also termed GDF-10) is a novel BMP-3 related protein recently discovered in rat femur tissue by molecular cloning. In this paper, we have isolated cDNA and the gene for human BMP-3b and determined their structure. Cloned human BMP-3b cDNA with a size of 2632 base pairs encodes a 478 amino acid precursor protein sharing 83% identity with rat BMP-3b. The human BMP-3b gene is composed of 3 exons and spans approximately 13 kilobases of DNA. The 5' flanking region carries no typical TATA box but G+C rich sequences. Southern blot analysis revealed that the BMP-3b gene is situated in a single locus of chromosome 10. By Northern analysis, human BMP-3b transcripts were detected primarily in femur, brain, lung, skeletal muscle, pancreas and testis.

Amino Acid Sequence↗
PubMed1996

Restricted usage of T-cell receptor Valpha-Vbeta genes in infiltrating cells in aortic tissue of patients with Takayasu's arteritis.

BACKGROUND: Infiltration by perforin-secreting killer lymphocytes, such as T cells and natural killer cells, has been shown to be involved in the pathogenesis of vascular cell damage in Takayasu's arteritis. METHODS AND RESULTS: To investigate the immunological mechanisms involved, especially the nature of T-cell infiltration in Takayasu's arteritis as well as atherosclerosis, we analyzed the expression of T-cell receptor (TCR) Valpha and Vbeta genes in infiltrating cells in the aortic tissue of patients with Takayasu's arteritis and the atherosclerotic aortic aneurysm by polymerase chain reaction (PCR). We also analyzed the expression of cytokine genes by PCR. We found that the repertoires of TCR Valpha as well as Vbeta gene transcripts in Takayasu's arteritis were restricted. The infiltrating cells expressing Valpha2, Valpha16, Valpha17, Vbeta7, and Vbeta13.1 were found in 3 of 4 patients. In contrast, TCR Valpha-Vbeta repertoires in atherosclerotic aortic aneurysm were polyclonal. There was no significant difference in the pattern of cytokine gene expression between the two diseases. CONCLUSIONS: The restricted usage of TCR Valpha as well as Vbeta genes by infiltrating T cells in Takayasu's arteritis may indicate that a specific antigen in the aortic tissue was targeted. Our findings provide the evidence that distinct immunological mechanisms are involved in the pathogenesis of Takayasu's arteritis and atherosclerotic aortic aneurysm.

Aged↗
PubMed1996

Identification of biologically active and inactive human uroguanylins in plasma and urine and their increases in renal insufficiency.

Uroguanylin, a 16-amino acid peptide, is an endogenous activator of intestinal and possibly renal guanylate cyclase C (GC-C). Using two synthetic topological isoforms of human uroguanylin, one bioactive, the other inactive, we prepared two antisera specific for the individual isoforms and developed sensitive radioimmunoassay (RIAs). The respective plasma concentrations of the bioactive and inactive uroguanylins in the normal individuals tested were 5.0 +/- 0.3 fmol/ml (mean +/- SE) and 1.6 +/- 0.1 fmol/ml. These concentrations increased in chronic renal failure (CRF). The major endogenous uroguanylin molecule in normal human urine was 16 amino acids long, whereas in the plasma and urine of CRF patients the major molecule was 10-kDa prouroguanylin. The RlAs established are promising tools for clarifying the physiological functions and pathophysiological implications of uroguanylin in water and electrolyte homeostasis.

Biomarkers↗
PubMed1996

Cloning and characterization of a cDNA encoding a precursor for human uroguanylin.

Uroguanylin, a member of the guanylin peptide family, is an endogenous activator of intestinal guanylate cyclase (GC-C). A cDNA encoding a precursor for human uroguanylin was cloned from a human colon cDNA library and sequenced. The precursor was 112 amino acids long and included a signal peptide at the N-terminus and the human uroguanylin sequence at the C-terminus. RNA blot analysis and the reverse transcription-polymerase chain reaction (RT-PCR) showed that human uroguanylin mRNA is expressed in the stomach and intestine. Uroguanylin, as well as guanylin, may be a potent physiological regulator of intestinal fluid and electrolyte transport.

Amino Acid Sequence↗
PubMed1996

Identification of rat bone morphogenetic protein-3b (BMP-3b), a new member of BMP-3.

Rat bone morphogenetic protein-3 (BMP-3) cDNA and BMP-3b cDNA were isolated from rat femur cDNA library by the RT-PCR method using degenerate oligonucleotide primers corresponding to human BMP-3. The deduced amino acid sequence of rat BMP-3 in the mature region reveals 2 amino acid changes compared to that of human BMP-3 (98% identity). The deduced BMP-3b amino acid sequence shows 81% similarity with the mature region of rat BMP-3 and only 37% similarity with the propeptide region. By Northern blot analysis, rat BMP-3b mRNA was detected in costa, costicartilage, femur, calvaria, trachea, aorta and brain. Among these tissues, BMP-3b transcripts were predominantly expressed in cerebellum. BMP-3 mRNA was found in femur, calvaria, trachea, lung and ovary. Although BMP-3b and BMP-3 are very closely related to each other, their transcripts are distributed in different tissues except that both are found in bone. The distribution pattern of BMP-3b mRNA suggests that BMP-3b plays an important role in the central nervous system as well as in bone formation and remodeling.

Aging↗
PubMed1996

Biopharmaceutical evaluation of the liposomes prepared by rehydration of freeze-dried empty liposomes (FDELs) with an aqueous solution of a drug.

We have evaluated a method for preparation of a dispersion of liposomes encapsulating a drug, namely rehydration of freeze-dried empty (not containing drug) liposomes with an aqueous drug solution (FDEL method). In the present study, we characterized and compared this method with the conventional method using a lipid composition of DPPC-DPPG-cholesterol in a molar ratio of 27:3:20. Two hydrophilic compounds, [3H]-inulin and [3H]-mannitol, were used as model drugs. Liposomal preparations by the FDEL method had an encapsulation efficiency of 2.9 and 6.7% for [3H]-inulin and [3H]-mannitol, respectively, when rehydrated and incubated at 70 degrees C. Since non-specific adsorption of these markers to liposomal membrane is negligible, this method produces liposomes which encapsulate a drug in the intravesicular space. One-tenth of the marker encapsulated in the liposomes prepared by the FDEL method (F-liposomes) was released very rapidly on incubation with rat plasma, followed by the slow release of the remaining fraction thereafter. No such rapid-release phase was observed for the liposomes prepared by the conventional method (C-liposomes). This suggests the existence of two types of encapsulation, loose encapsulation and tight encapsulation, in F-liposomes at least. Pharmacokinetic parameters of marker encapsulated tightly in F-liposomes were comparable to those in C-liposomes. It is likely that amphipathic drugs such as doxorubicin are incorporated into liposomes more easily than inulin and mannitol when formulated by the FDEL method. These results therefore suggest that the FDEL method is useful in the preparation of a liposomal formulation of a drug.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

TNF-alpha stimulates glucose uptake in L6 myoblasts.

The mechanism of TNF-alpha to regulate glucose metabolism remains unclear. To further delineate the TNF-alpha signal transduction pathway mediating glucose metabolism, we utilized L6 rat myoblasts which contain the receptors for the insulin-like growth factor-I (IGF-I) and TNF-alpha, and the ability of both ligands to stimulate glucose uptake was compared. IGF-I (6.5 nM) maximally stimulated glucose uptake 7-fold after 24 h incubation, while 23 nM TNF-alpha maximally stimulated glucose uptake 3-fold only after 48 h incubation. IGF-I receptor beta-subunit, insulin receptor substrate-1 (IRS-1), and mitogen-activated protein (MAP) kinase were all phosphorylated in response to 6.5 nM IGF-I after 10 min incubation. In contrast, the treatment with 23 nM TNF-alpha failed to phosphorylate either IGF-I receptor beta-subunit or IRS-1 but did phosphorylate MAP kinase as much as IGF-I did. Despite a similar extent to which TNF-alpha induced MAP kinase phosphorylation as IGF-I did, TNF-alpha stimulated glucose uptake less compared to IGF-I. The results indicate that MAP kinase phosphorylation is not sufficient for glucose uptake in L6 myoblasts. TNF-alpha-elicited signal transduction to glucose uptake may utilize a different pathway from that seen with IGF-I.

Animals↗