Search PubMed⌕ Search

Biomedical subjects

Y Natori

Publications and source records attributed to Y Natori.

At least 19 recordsLinked to original sources
PubMed2000

Transient and sequential expression of chemokine mRNA in glomeruli in puromycin aminonucleoside nephrosis.

Chemokines are a large family of low-molecular-weight proinflammatory cytokines that stimulate recruitment of leukocytes. We previously reported that among six chemokines, the expression of mRNAs for MCP-1, MCP-3, TCA3, and MIP-1alpha, but not for MIP-1beta and RANTES, was markedly elevated in the renal cortex of rats with puromycin aminonucleoside induced nephrosis. In this study we have determined the glomerular expression of the chemokine mRNAs in this model using quantitative competitive reverse-transcriptase polymerase chain reaction. After an injection of puromycin aminonucleoside, the number of monocytes/macrophages and CD4+ and CD8+ cells markedly increased by day 5 and increased thereafter until day 10. The levels of mRNAs for MCP-1, MCP-3, and lymphotactin increased on day 5 and returned to their normal levels by day 7. The level of TCA3 mRNA increased on day 3, and that of MIP-1alpha mRNA increased on day 7, but both returned to their normal levels within 2 days. No increase in the mRNAs of MIP-1beta or RANTES was observed until day 10. These results indicate that the expression pattern of the chemokine mRNAs in glomeruli resembles that in renal cortex, but is more transient and sequential.

Animals↗
PubMed2000

[Infratemporal fossa approach for mid-skull base lesion: its usefulness, surgical anatomy, and intraoperative device].

The usefulness of the infratemporal fossa type C approach is reported through a presentation of a case of clival chordoma, which was successfully treated by this approach. Although it is complicated and includes some demerits, this approach gives a shorter and wider access to mid-skull base pathology than other approaches. Among the demerits, deformity of the temporal region caused by extensive drilling of the bone could be minimized by cosmetic mastoidectomy, which was first applied during this approach by the authors. The surgical anatomy for this approach is demonstrated using a cadaver specimen.

Adult↗
PubMed1999

Analysis of the fatty acid components in a perchloric acid-soluble protein.

We had previously found that a perchloric acid-soluble protein (PSP1) occurs in rat liver, and that this novel protein inhibits protein synthesis in a rabbit reticulocyte lysate system (T. Oka, H. Tsuji, C. Noda, K. Sakai, Y.-H. Hong, I. Suzuki, S. Muñoz, Y. Natori, J. Biol. Chem. 270 (1995) 30060-30067). In the present study, we analyzed lipid components bound to PSP1. Native PSP1 was purified from rat liver using Sephadex G-75, DE-52 cellulose and IgGPSP-affinity chromatography, and the lipid components were extracted. The components obtained from the purified PSP1 were shown to be free fatty acids by thin-layer chromatography. By GC-MS, six major fatty acids were identified as 14:0, 16:0, 18:0, 18:1, 18:2 and 20:4. 1 mol of PSP1 contained 1.26 mol of total fatty acid components. The fatty acid-binding assay of PSP1 showed that the Bmax was 1.25 mol fatty acid/mol PSP1 and the Kd value for palmitic acid was 6.03 microM. The concentration of PSP1 mRNA in rat liver increased 2.3-fold by the administration of peroxisome proliferator, bezafibrate. These findings show that PSP1 is a fatty acid-binding protein-like protein, which is involved in the intracellular metabolism of fatty acid and is quite different from the known fatty acid-binding proteins.

Animals↗
PubMed1999

Induction of cytokines in a human colon epithelial cell line by Shiga toxin 1 (Stx1) and Stx2 but not by non-toxic mutant Stx1 which lacks N-glycosidase activity.

Stx1 and Stx2 produced by Shiga toxin-producing Escherichia coli are cytotoxic due to their N-glycosidase activity on 28S rRNA. In this study, we have shown that proinflammatory cytokine mRNAs, especially IL-8, were induced by Stx1 and Stx2 in Caco-2 cells. A non-toxic mutant of Stxl which lacks N-glycosidase activity did not induce cytokine mRNAs. IL-8 production at the protein level was enhanced by Stx1 and Stx2, but not by the mutant Stx1. These results demonstrate that Shiga toxins induce expression and synthesis of cytokines in Caco-2 cells and their N-glycosidase activity is essential for the induction.

Amino Acid Substitution↗
PubMed1999

Huge hamartoma with inverted papilloma in the nasal cavity.

We report clinical experience in managing a 46-year-old Japanese man with long-standing nasal obstruction resulting from a huge left nasal mass. Computed tomography, magnetic resonance imaging and biopsy were used to make a provisional diagnosis of inverted papilloma. The mass was resected via a frontal approach combined with rhinotomy. Histopathologic examination of the resected specimen was consistent with a hamartoma that included an inverted papilloma on a portion of its surface. In addition to being rare tumors in the nasal cavity, we believe that our patient's tumor the largest nasal hamartoma ever reported.

Biopsy↗
PubMed1999

Production of functional rat liver PSP protein in Escherichia coli.

An efficient Escherichia coli expression system for the production of a perchloric acid-soluble protein (PSP) has been constructed. Complementary DNA encoding PSP was inserted into an inducible bacterial expression vector pGEX-4T-1. After the plasmid introduced into E. coli was expressed by isopropyl 1-thio-beta-D-galaetopyranoside (IPTG), the recombinant product was purified by glutathione-Sepharose 4B affinity chromatography. The purified product showed the expected NH2-terminal sequence, but the translation inhibitory activity of this product was 10 times lower compared with that of authentic PSP isolated from rat liver.

Animals↗
PubMed1999

Therapeutic effect of glucocorticoid on experimental crescentic glomerulonephritis.

Crescentic glomerulonephritis shows active and progressive glomerular changes with rapid deterioration in kidney function. A large dose of glucocorticoid (pulse therapy) is clinically used for the treatment, but its efficacy has not been fully estimated. In this study we assessed the therapeutic effect of a large dose of methyl-prednisolone (MP) on a rat model of crescentic glomerulonephritis that had been induced in WKY rats by an injection of anti-glomerular basement membrane antibody. The infiltration of CD8+ cells and monocytes was manifest by day 3, proteinuria appeared on days 4 and 5, and cellular crescents were diffusely formed by day 7. The gene expression of MCP-1, a chemokine for monocytes and T lymphocytes, was enhanced within 4 hours and peaked on day 3. Daily administration of MP (30 mg/kg/d) from day 3 through day 6 reduced the gene expression of MCP-1 and the numbers of glomerular leukocytes and largely prevented both crescent formation and proteinuria. When daily MP treatment started on day 7, the numbers of glomerular CD8+ cells and monocytes, crescents, and urinary protein were significantly reduced by day 11. In addition, continuing treatment with a small dose of MP (3 mg/kg/d) begun on day 11 completely prevented the increase in blood urea nitrogen and serum creatinine levels. These results indicate that treatment with a large dose of MP histologically and clinically ameliorates crescentic glomerulonephritis in a rat model, supporting the efficacy of pulse MP therapy for the treatment of the disease in human subjects.

Animals↗
PubMed1999

Gene expression of CC chemokines in experimental acute tubulointerstitial nephritis.

The infiltration of mononuclear leukocytes into glomeruli or the interstitium is a feature in most forms of glomerular diseases. CC chemokines, mostly chemoattractants for mononuclear leukocytes, are molecules that are potentially responsible for the recruitment of these cells in the kidney. We previously reported that the gene expression of six CC chemokines-MCP-1, MCP-3, MIP-1alpha, MIP-1beta, RANTES, and TCA3-was enhanced in a rat model of crescentic glomerulonephritis, the most severe form of glomerulonephritis. In this study we analyzed their gene expression in a model of another type of kidney disease, acute nephrosis accompanied by tubulointerstitial lesions, which is induced by an injection of puromycin aminonucleoside. Because leukocyte infiltration in this model is much more prominent in the interstitium than in glomeruli, we analyzed their gene expression in the renal cortex. On day 3, when the level of urinary protein was slightly but significantly increased but the number of interstitial leukocytes was unchanged, the enhanced expression of mRNAs for MCP-1, MCP-3, and TCA3 was observed. On day 5, the numbers of interstitial monocytes and lymphocytes significantly increased, and the levels of the mRNA expression of the above chemokines were still higher than the control animals, whereas the levels of mRNAs for MIP- 1alpha, MIP-1beta, and RANTES were not higher or were only slightly higher than the control ones. These results suggest that multiple CC chemokines may play a role in the recruitment of leukocytes in this model and that the expression pattern of CC chemokines depends on the type of kidney injury.

Acute Disease↗
PubMed1999

A historical cohort mortality study of workers exposed to asbestos in a refitting shipyard.

To investigate the risks of developing asbestos-related diseases we conducted a historical cohort mortality study on 249 ship repair workers (90 laggers and 159 boiler repairers) in a single U.S. Navy shipyard in Japan. We successfully identified the vital status of 87 (96.7%) laggers and 150 (94.3%) boiler repairers, and, of these, 49 (56.3%) and 65 (43.3%) died, respectively, during the follow-up period from 1947 till the end of 1996. Our in-person interviews with some of the subjects clarified that asbestos exposure was considered to be substantially high in the 1950-60s, decreased thereafter gradually but remained till 1979 in the shipyard. The laggers, who had handled asbestos materials directly, showed a significantly elevated SMR of 2.75 (95% C.I.: 1.08-6.48) for lung cancer. The risk developing the disease was greater in the laggers after a 20-year latency (SMR = 3.42). Pancreatic cancer yielded a greater SMR than unity (7.78, 90% C.I.: 2.07-25.19) in a longer working years group. Four laggers died from asbestosis. The boiler repairers, who had many chances for secondary exposure to asbestos and a few for direct exposure, showed no elevation of the SMR of lung cancer overall, but there was a borderline statistically significant SMR of 2.41 (90% C.I.: 1.05-5.45) in a longer working years group. One boiler repairer died from mesothelioma and four from asbestosis.

Adult↗
PubMed1999

[Clinical experience of image-guided neurosurgery with a frameless navigation system (StealthStation)].

We have applied the frameless navigation system (StealthStation) to various neurosurgical procedures to examine its usefulness. The system consists of a UNIX based workstation that creates triplanar and 3-dimensional images; an infrared optical digitizer with camera array; a reference-light-emitting diode (LED) array (e.g., reference array); and pointer probe modified by the addition of LEDs. This system was used to assist in placing a minimal skin incision and craniotomy in 4 cases, to determine the tumor/brain interface in 2 cases, to target the subcortical lesion in one case, and to correlate bony structure with a skull base tumor in 3 cases. The combined use with magnetic source imaging of the somatosensory cortex allowed a fast orientation of eloquent areas in 2 cases with peri-Rolandic tumor. This system, thus, was proved to be a useful adjunct to open-tumor biopsy or resection.

Adult↗
PubMed1998

Expression of lymphotactin mRNA in experimental crescentic glomerulonephritis.

Lymphotactin (LTN) is the sole member of C chemokine, the third subfamily of chemokines. LTN has been shown to be a chemoattractant specific for CD8+ cells and/or natural killer (NK) cells, and to be produced by CD8+ T cells, NK cells, and mast cells. However, there have been no reports describing its expression in clinical or experimental models of diseases so far. Since glomerular infiltration of CD8+ cells is prominent in an animal model of crescentic glomerulonephritis induced in WKY rats by an injection of anti-glomerular basement membrane antibody, we investigated the gene expression of LTN in this model. LTN mRNA was not detected in normal glomeruli but was detected at 0.5 h after the antibody injection, which detection preceded the infiltration of CD8+ cells. The expression of LTN mRNA peaked on day 3 and decreased thereafter. We next studied the expression of LTN mRNA in cultured glomerular and vascular cells, and found that glomerular mesangial and vascular endothelial cells could express LTN mRNA when stimulated with IL-1beta. These results indicate that the gene expression of LTN is enhanced in the animal model of glomerulonephritis and that intrinsic renal cells are the potential source of the gene expression of LTN in the kidney.

Animals↗
PubMed1998

A simple procedure for the isolation of rat kidney lysosomes.

BACKGROUND: A procedure for the isolation of highly purified lysosomes from normal rat kidney is described. METHODS: The method depends on the swelling of mitochondria when the postnuclear supernatant fraction is incubated with 2 mM Ca2+. The lysosomes can then be separated from the swollen mitochondria by Percoll density gradient centrifugation. RESULTS: The lysosomal fraction obtained by our method was enriched more than 30-fold in terms of marker enzymes with a yield of about 11%. Electron microscopic examination and the measurement of the activities of marker enzymes for various subcellular organelles indicated that our lysosomal preparation was essentially free from contamination by other organelles. CONCLUSION: We believe that this procedure for isolating kidney lysosome will be useful in the study of the mechanisms of specific modification, processing and catabolism of proteins.

Albumins↗
PubMed1998

Purification, characterization and differentiation-dependent expression of a perchloric acid soluble protein from rat kidney.

We have recently reported the presence of a novel perchloric acid soluble protein in rat liver (PSP1) that inhibits cell-free protein synthesis in a rabbit reticulocyte system. While studying the perchloric acid soluble proteins from different tissues of rats, we found that the kidney protein cross-reacted with antibody against the PSP1. In this investigation, we have purified a perchloric acid soluble protein from the rat kidney and studied its characterization and expression. The protein extracted from the postmitochondrial supernatant fraction with 5% perchloric acid was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. By immunoscreening with the rabbit antisera against the PSP1, we detected a cDNA that contained an open reading frame of 411 bp, encoding a 137 amino-acid protein with a molecular mass of 14,149 daltons. The deduced amino acid sequence was completely identical with that of PSP1 from rat liver. The perchloric acid soluble protein from rat kidney (K-PSP1) also inhibited cell-free protein synthesis in the rabbit reticulocyte lysate system in a different manner than RNase A. Immunohistochemistry showed that the expression of K-PSP1 increased from fetal 17th day to postnatal 4th week, and it remained almost the same until the 7th week of postnatal age. Furthermore, the expression of K-PSP1 in the kidney of the nephrotic rat model was shown to be differentiation dependent. On the other hand, the expression of K-PSP1 in renal tumor cells was downregulated as compared with intact tissue. These results suggest that the expression of K-PSP1 is regulated in a differentiation-dependent manner in the kidney.

Amino Acid Sequence↗
PubMed1998

Characterization of fibronectin-related substances in normal and passive Heymann nephritis rats.

The excretion mechanism of fibronectin (FN)-related substances into the urine of normal and passive Heymann nephritis (PHN) rats was studied using enzyme immunoassay and immunoblot analysis. In normal rats, a small amount (0.20+/-0.067 microg/d) of FN-related substances, composed of 55- and 65-kDa FN fragments derived from the central cell-binding (Cell) domain of FN, were constitutively excreted into the urine. When PHN was induced in rats by the injection of an anti-Fx1A antibody, an increased excretion (4.96+/-3.51 microg/d) of intact FN and large (Mr > 100-kDa) FN fragments containing the Cell and the other functional domains were seen. The PHN induction also caused the appearance of a considerable amount of Cell domain-containing FN fragments in plasma. Both the renal cortex homogenates of normal and PHN rats were capable of degrading plasma FN to generate the Cell domain-containing large FN fragments. Degradation of FN by the renal cortex homogenate was shown to be due to metal and/or thiol proteinase(s). These results suggest that the PHN-induced urinary excretion of FN fragments may be due to the degradation of plasma FN by renal proteinases that may be leaked upon PHN induction.

Animals↗
PubMed1998

cDNA cloning, expression, and characterization of the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate kinase enzyme.

A cDNA encoding the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate (APS) kinase was cloned and sequenced. The enzyme contains an APS kinase domain in its N-terminal portion and an ATP sulfurylase domain in its C-terminal portion. Recombinant full-length enzyme and its constituent APS kinase and ATP sulfurylase domains were individually expressed, purified, and shown to have their respective enzymatic activities.

Amino Acid Sequence↗