Biomedical subjects

T Gotoh

Publications and source records attributed to T Gotoh.

At least 73 records · Page 4Linked to original sources

PubMed2000

Expression of receptors for glial cell line-derived neurotrophic factor (GDNF) and neurturin in the inner blood-retinal barrier of rats.

The retina is protected from somatic circulation by the blood-retinal barrrier (BRB) composed of tight junctions between retinal vascular endothelial cells (the inner BRB) and those between retinal pigment epithelial cells (the outer BRB). Our recent studies showed that glial cell line-derived neurotrophic factor (GDNF) secreted from astrocytes regulates the permeability of the BBB. In the present study, we immunohistochemically examined the expression of GDNF, neurturin (NTN) and their receptors, GFRalpha1 for GDNF and GFRalpha2 for NTN, because the capillaries of the inner BRB show specialization very similar to the blood-brain barrier (BBB). GDNF and NTN were detected in glial fibrillary acidic protein (GFAP)-positive cells, including Müller cells. GFRalpha1 and GFRalpha2 were localized in von Willebrand factor-positive cells. GDNF and NTN enhanced the barrier function of endothelial cells derived from porcine brain cortex. These results strongly suggest that the barrier function of the BRB is regulated by GDNF and NTN secreted from glial cells, like the BBB.

Animals↗

PubMed2000

Five-year intra-individual variability in C-reactive protein levels in a Japanese population-based study: the Jichi Medical School Cohort Study at Yamato, 1993-1998.

C-reactive protein (CRP) is an acute-phase reactant that is related to future cardiovascular events. However, little is known about the long-term intra-individual stability of CRP in community residents. The 5-year intra-individual correlation of CRP levels was examined in the Jichi Medical School Cohort Study in Japan. CRP measurements were obtained in 1993 and in 1998 from 388 presumptively healthy individuals aged 30-69 years at baseline. The Pearson's correlation coefficient of CRP between baseline and follow-up measurements was 0.43 (95% confidence interval (CI): 0.34-0.51). Additional analyses by sex and smoking status at baseline revealed similar coefficients. The correlation coefficient of CRP was lower than that of other classical risk factors, such as body-mass index (BMI), blood pressure, and total and high-density lipoprotein (HDL) cholesterol. A subgroup of individuals with higher levels of CRP at both baseline and follow-up measurements had higher BMI, hemoglobin Alc, and plasma fibrinogen, and lower levels of HDL-cholesterol than others, even after adjusting for age, sex, and smoking status in a multiple logistic model. In conclusion, the stability of CRP levels was statistically significant in a long-term population-based study. A subgroup with higher levels of CRP who had an aggregation of cardiovascular risk factors was identified by the 2 measurements.

Adult↗

PubMed2000

[Renal inflammatory pseudotumor after embolization for arteriovenous malformation: a case report].

A 61-year-old man was admitted to our hospital with the chief complaint of asymptomatic macrohematuria. Because he was diagnosed with arteriovenous malformation of the right kidney by angiography, embolization was performed. However, 2 years and 3 months later, bleeding from the right kidney was detected. Computed tomography (CT) revealed a low density area (1.8 cm) in the right kidney protruding to the renal pelvic adjacent to the old embolized lesion. Since we could not make a conclusive diagnosis as malignant disease by ureteroscopy and angiography, we have decided to follow the case carefully. Nine months later, macroscopic hematuria worsened, and the low density area by CT in the right kidney expanded. Therefore, we finally decided to perform right total nephroureterectomy. The tumor was histologically diagnosed as renal inflammatory pseudotumor. This is the 14th case reported in Japan. We here report the renal inflammatory pseudotumor with a review of the Japanese literature.

Arteriovenous Malformations↗

PubMed2000

Expression and localization of enzymes of arginine metabolism in the rat eye.

PURPOSE: Production of NO may be regulated by argininosuccinate synthetase and argininosuccinate lyase which recycle citrulline to arginine, and by arginase which hydrolyzes arginine to urea and ornithine. Expression of these and related enzymes in rat eye was studied. METHODS: mRNAs for the enzymes were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Localization of the enzyme proteins and mRNAs was analyzed by immunohistochemistry and in situ hybridization, respectively. RESULTS: In RT-PCR analysis, arginase II (nonhepatic type) mRNA was detected in retina and weakly in cornea, whereas arginase I (hepatic type) mRNA was not detected in any area. mRNAs for argininosuccinate synthetase, argininosuccinate lyase, ornithine aminotransferase and ornithine decarboxylase were present in all areas. In immunohistochemical analysis, arginase II was stained in cornea, epithelium of iris and ciliary process, inner part of neural retina and retinal pigment epithelium. Immunostaining of ornithine aminotransferase resembled that of arginase II. In in situ hybridization, arginase II and ornithine aminotransferase mRNAs were located much as seen with the enzyme proteins. CONCLUSIONS: These results indicate that arginine recycling activity from citrulline is present widely in ocular tissues, whereas expression of arginase II differs among the tissues. We suggest that NO production may be regulated by these enzymes in the cells where NO synthase is colocalized. Colocalization of arginase II and ornithine aminotransferase suggests a role for arginase II in collagen synthesis in the eye.

Animals↗

PubMed2000

Enhanced neutrophilic granulopoiesis in rheumatoid arthritis. Involvement of neutrophils in disease progression.

OBJECTIVE: To investigate enhanced granulopoiesis in bone marrow of patients with rheumatoid arthritis (RA), and the role of neutrophils in RA pathogenesis. METHODS: Aspirated bone marrow cells and peripheral blood leukocytes from patients with RA and non-RA patient controls were analyzed morphologically and by 2 color flow cytometry. Thirteen iliac bones (8 RA, 5 non-RA) were examined by light and transmission electron microscope (TEM). RESULTS: The percentage of CD15+CD16- cells (immature neutrophils) in RA bone marrow (64.3+/-13.4%, mean +/- SD) increased significantly compared to that of non-RA controls (43.2+/-14.3%), whereas the fraction of CD15+CD]6+ cells (mature neutrophils)was greatly decreased (RA 21.8+/-10.1%; non-RA 38.1+/-8.9%). The absolute number of CD15+CD16- cells also increased markedly in RA bone marrow. The ratio of immature cells to the total granulocytes (% CD15+CD16- to % CD15+) correlated with the Lansbury Index score (R = 0.76, p<0.0001). TEM observations revealed that abundant immature neutrophils adhered closely to the trabeculae of the iliac bone. Margins of trabeculae were mostly irregular, especially in severe RA, and collagenous fibers frequently disappeared in those trabeculae with ragged margins. CONCLUSION: In RA bone marrow, immature neutrophils (CD15+CD16-) were markedly increased in number; by contrast, no changes were found for mature cells. Augmented production of immature neutrophils (at the promyelocyte-to-myelocyte stage) might lead to the destruction of collagenous fibers in RA bone trabeculae, as revealed by TEM. Generalized bone destruction in RA might, at least in part, be caused by enhanced production of immature neutrophils.

Adult↗

PubMed2000

[A case of urinary stone in ureterocele extracted transurethrally after ESWL].

A 66-year-old man was referred to our hospital with chief complaints of difficulty in urination and terminal micturition pain. Ureteroceles were identified bilaterally, and a ureteral stone (19 x 12 mm) existed in the right ureterocele. After crushing the stone by extra corporeal shock wave lithotripsy (ESWL), we removed the stone transurethrally with a small incision in the right ureterocele. The vesicoureteral reflux (VUR) was not detected postoperatively. Now, we recommend the combination of ESWL and a small transurethral incision of the urelerocele for the treatment of ureteral stones in a ureterocele in order to prevent postoperative VUR.

Aged↗

PubMed2000

[A case of ammonium urate urinary stones with anorexia nervosa].

A 27-year-old woman had been suffering from bulimia and habitual vomiting for about 7 years and was incidentally found to have right renal stones by computed tomography. She was referred to our hospital for the treatment of these caluculi. On admission, she presented with hypokalemia, hypochloremia and metabolic alkalosis and was diagnosed with anorexia nervosa. Following successful removal by percutaneous nephrolithotripsy and extracorporeal shockwave lithotripsy the stones were found to consist of pure ammonium urate. Since the urine of an anorexia nervosa patient tends to be rich in uric acid and ammonium, anorexia nervosa seems to be associated with ammonium urate urinary stones.

Adult↗

PubMed1999

Expression of citrulline-nitric oxide cycle in lipopolysaccharide and cytokine-stimulated rat astroglioma C6 cells.

Nitric oxide (NO) is involved in many physiological and pathological processes in the brain. NO is synthesized from arginine by nitric oxide synthase (NOS), with citrulline generated as a by-product of the reaction. Thus, citrulline can by recycled to arginine by argininosuccinate synthetase (AS) and argininosuccinate lyase (AL) via the citrulline-NO cycle. Rat astroglioma C6 cells were treated with bacterial lipopolysaccharide (LPS), interferon-gamma (IFNgamma) and tumor necrosis factor-alpha, and the expression of the enzymes of the citrulline-NO cycle was investigated by RNA blot and immunoblot analyses. NO production from arginine and citrulline was also assessed. iNOS mRNA and protein were induced 6-12 h after stimulation with LPS and cytokines and decreased at 24 h. AS mRNA increased up to 12 h and decreased at 24 h. AS protein increased gradually up to 48 h. On the other hand, AL mRNA remained unchanged by stimulation. NO production from arginine was enhanced by the treatment with LPS and cytokines. NO production was also observed when arginine was replaced by citrulline. These results indicate that NO production is enhanced in LPS- and cytokine-stimulated C6 cells due to induction of iNOS and that the citrulline-arginine recycling is important for NO production.

Animals↗

PubMed1999

L-arginine uptake, the citrulline-NO cycle and arginase II in the rat brain: an in situ hybridization study.

Nitric oxide (NO) is synthesized from a unique precursor, arginine, by nitric oxide synthase (NOS). In brain cells, arginine is supplied by protein breakdown or extracted from the blood through cationic amino acid transporters (CATs). Arginine can also be recycled from the citrulline produced by NOS activity, through argininosuccinate synthetase (AS) and argininosuccinate lyase (AL) activities, and metabolized by arginase. NOS, AS and AL constitute the so-called citrulline-NO cycle. In order to better understand arginine transport, recycling and degradation, we studied the regional distribution of cells expressing CAT1, CAT3, AS, AL, neuronal NOS (nNOS) and arginase II (AII) in the adult rat brain by non-radioisotopic in situ hybridization (ISH). CAT1, AL and AII presented an ubiquitous neuronal and glial expression, whereas CAT3 and AS were confined to neurons. nNOS was restricted to scattered neurons and a few brain nuclei and layers. We demonstrate by this study that cells expressing nNOS all appear to express the entire citrulline-NO cycle, whereas numerous cells expressing AL do not express AS. The differential expression of these genes within the same anatomical structure could indicate that intercellular exchanges of citrulline-NO cycle metabolites are relevant. Thus vicinal interactions should be taken into account to study their regulatory mechanisms.

Amino Acid Transport Systems, Basic↗

PubMed1999

Arginase II downregulates nitric oxide (NO) production and prevents NO-mediated apoptosis in murine macrophage-derived RAW 264.7 cells.

Excess nitric oxide (NO) induces apoptosis of some cell types, including macrophages. As NO is synthesized by NO synthase (NOS) from arginine, a common substrate of arginase, these two enzymes compete for arginine. There are two known isoforms of arginase, types I and II. Using murine macrophage-like RAW 264.7 cells, we asked if the induction of arginase II would downregulate NO production and hence prevent apoptosis. When cells were exposed to lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma), the inducible form of NOS (iNOS) was induced, production of NO was elevated, and apoptosis followed. When dexamethasone and cAMP were further added, both iNOS and arginase II were induced, NO production was much decreased, and apoptosis was prevented. When the cells were transfected with an arginase II expression plasmid and treated with LPS/IFN-gamma, some cells were rescued from apoptosis. An arginase I expression plasmid was also effective. On the other hand, transfection with the arginase II plasmid did not prevent apoptosis when a NO donor SNAP or a high concentration (12 mM) of arginine was added. These results indicate that arginase II prevents NO-dependent apoptosis of RAW 264.7 cells by depleting intracellular arginine and by decreasing NO production.

Animals↗

PubMed1999

Expression of inducible nitric oxide synthase and enzymes of arginine metabolism in Fusarium kyushuense-exposed mouse lung.

Expression of inducible nitric oxide (NO) synthase (iNOS) and related enzymes of arginine metabolism in the mouse lung exposed to filamentous fungus Fusarium kyushuense was studied by RNA blot, immunoblot, and histological analyses. When mice were exposed intranasally to the fungi only once, no induction of iNOS mRNA was observed. However, when the animals were infected again 6 days after the first exposure, iNOS mRNA was induced, reached a maximum 12-24 h after the exposure, and decreased to an undetectable level at 48 h. mRNAs for cationic amino acid transporter-2 (CAT2) and argininosuccinate synthetase were induced gradually, reached a maximum at 24 h, and decreased at 48 h. Arginase II mRNA increased at 24 h and decreased markedly at 48 h. On the other hand, arginase I mRNA started to increase at 24 h and reached to a much higher level at 48 h. Ornithine decarboxylase and ornithine aminotransferase mRNAs were also induced. Immunoblot analysis showed that iNOS, argininosuccinate synthetase, and arginase I and II proteins were induced with similar kinetics as those of their respective mRNAs. In histological examination, fungal elements were observed in the bronchoalveolar lumen at 3-6 h, decreased at 12 h, and almost disappeared at 48 h. Small granuloma appeared 3 h after the infection and their size increased with time. These results suggest that NO is produced in the mouse lung in response to F. kyushuense exposure and that the NO production is regulated by CAT2, the citrulline-NO cycle, and arginase isoforms. Enhanced synthesis of polyamines and proline (and thus collagen) is also suggested.

Amino Acid Transport Systems, Basic↗

PubMed1999

Optical coherence tomography of successfully repaired idiopathic macular holes.

PURPOSE: To present the cross-sectional retinal imaging results of optical coherence tomography in eyes with successfully repaired idiopathic macular hole and their relevance to visual recovery. METHODS: We studied 33 eyes with successful repair of an idiopathic macular hole through vitrectomy and fluid-gas exchange from 32 patients (11 men and 21 women) with ages ranging from 48 to 78 years, with a median age of 66 years. Preoperative conditions in eyes with primary surgery disclosed nine eyes with stage 2, 14 eyes with stage 3, and four eyes with stage 4 macular hole. An additional six eyes underwent a second surgery because the previous surgery was unsuccessful. Measurement of best-corrected visual acuity, slit-lamp biomicroscopy with fundus contact lens, fundus photographs, and optical coherence tomographic examination were performed between 6 and 9 months after surgery in 29 eyes and between 15 and 36 months after surgery in four eyes. RESULTS: Optical coherence tomographic images of the repaired macular holes were categorized into three patterns. U-type (normal foveal contour; 13 eyes) showed mildly to moderately backscattering layers with a smooth circular surface covering retinal pigment epithelium and choriocapillaris layers. In eyes with V-type (steep foveal contour; 13 eyes), the retinal pigment epithelium and choriocapillaris layers were covered with moderately backscattering layers with a notch. W-type (foveal defect of neurosensory retina; seven eyes) showed abruptly or gradually terminating sensory retinal layers to expose the surface of the retinal pigment epithelium and choriocapillaris layers. Postoperative acuity was well correlated with these patterns of optical coherence tomographic images. CONCLUSION: Assessment of successfully repaired idiopathic macular holes with optical coherence tomographic images provides a useful correlation with postoperative visual recovery.

Aged↗

PubMed1999

Evaluation of a clinic-based screening program for lung cancer with a case-control design in Kanagawa, Japan.

A case-control study was performed in Kanagawa Prefecture, Japan, which introduced lung cancer screening, by family physicians, to determine if this program was effective. The subjects were persons who died from lung cancer, restricted to those between 40 and 74 years old at death, and National Health Insurance (NHI) holders. A total of 193 lung cancer deaths meeting the criteria were selected for the case group. Three controls for each case were selected at random from living NHI holders matched by residence, gender and year of birth (+1 year). Smoking adjusted odds ratios were calculated using a multiple logistic regression model. The odds ratios of dying from lung cancer for screening participants within 12 months compared with non-participants was 0.535 which was statistically significant (95% CI, 0.337-0.850). The odds ratio in the 12-24-month period before diagnosis was 0.638 (0.302-0.967), which was also significant. The results demonstrated that screening for lung cancer by family physicians can reduce the lung cancer mortality, and that a clinic-based screening program by family physicians is effective.

Adult↗

PubMed1999

In vivo targeted gene transfer into liver cells mediated by a novel galactosyl-D-lysine/D-serine copolymer.

A novel synthetic polypeptide designed as a DNA binding-molecule for liver-specific, receptor-mediated, gene transfer was used to selectively introduce reporter genes into liver cells in the form of plasmid DNA-ligand complexes. The polypeptide was a D-lysine/D-serine copolymer (Lys/Ser = 33/36 or 53/60) modified with a polyethylene glycol 5000 at the carboxyl-terminus (PLSP). In addition, the lysine epsilon-amino groups were covalently bound to galactose (galactosyl-PLSP), a ligand for the asialoglycoprotein receptor on hepatocytes. Solutions of DNA-ligand complex were prepared by adding solutions of DNA and galactosyl-PLSP in a mixing ratio of DNA:galactosyl-PLSP = 1:3 (w/w). Following injection of the DNA-ligand complex into mice via the tail vein, high levels of luciferase and enhanced green fluorescent protein, which were encoded by the reporter genes, were observed in liver. In contrast, luciferase activity in kidney, spleen, lung and heart was negligible. The high levels of gene expression obtained with DNA/galactosyl-PLSP complexes were achieved without partial hepatectomy or administration of lysosomotrophic agents. Thus, the synthetic Lys/Ser copolymer used in the present study appears to be a promising new tool which enhances the efficacy of receptor-mediated gene transfer into hepatocytes and which may provide another step toward the clinical practice of organ-specific gene therapy.

Animals↗

PubMed1999

Synthesis of S-adenosyl-L-homocysteine hydrolase inhibitors and their biological activities.

Several nucleosides have been prepared as a possible inhibitor of human S-adenosyl-L-homocysteine (SAH) hydrolase for the development of anti-viral agents. Recently, SAH hydrolase has been considered as an attractive target for parasite chemotherapy for malaria. We report synthesis of several nucleosides including carbocyclic nucleosides and their inhibitory activities against recombinant malaria and human SAH hydrolases.

Adenine↗

PubMed1999

Expression of arginase II and related enzymes in the rat small intestine and kidney.

Arginase, which catalyzes the conversion of arginine to urea and ornithine, and consists of a liver-type (arginase I) and a non-hepatic type (arginase II). Arginine is also used for the synthesis of nitric oxide and creatine phosphate, while ornithine is used for the synthesis of polyamines and proline, and thus collagen. Arginase II mRNA and protein are abundant in the intestine (most abundant in the jejunum and less abundant in the ileum, duodenum, and colon) and kidney of the rat. In the kidney, the levels of arginase II mRNA do not change appreciably from 0 to 8 weeks of age. In contrast, arginase II mRNA and protein in the small intestine are not detectable at birth, appear at 3 weeks of age, the weaning period, and their levels increase up to 8 weeks. On the other hand, mRNAs for ornithine aminotransferase (OAT), ornithine decarboxylase, and ornithine carbamoyltransferase (OCT) are present at birth and their levels do not change much during development. Arginase II is elevated in response to a combination of bacterial lipopolysaccharide, dibutyryl cAMP, and dexamethasone in the kidney, but is not affected by these treatments in the small intestine. Immunohistochemical analysis of arginase II, OAT, and OCT in the jejunum revealed their co-localization in absorptive epithelial cells. These results show that the arginase II gene is regulated differentially in the small intestine and kidney, and suggest different roles of the enzyme in these two tissues. The co-localization of arginase II and the three ornithine-utilizing enzymes in the small intestine suggests that the enzyme is involved in the synthesis of proline, polyamines, and/or citrulline in this tissue.

Animals↗

PubMed1999

De novo synthesis of sphingolipids is required for cell survival by down-regulating c-Jun N-terminal kinase in Drosophila imaginal discs.

Mitogen-activated protein kinase (MAPK) is a conserved eukaryotic signaling factor that mediates various signals, cumulating in the activation of transcription factors. Extracellular signal-regulated kinase (ERK), a MAPK, is activated through phosphorylation by the kinase MAPK/ERK kinase (MEK). To elucidate the extent of the involvement of ERK in various aspects of animal development, we searched for a Drosophila mutant which responds to elevated MEK activity and herein identified a lace mutant. Mutants with mild lace alleles grow to become adults with multiple aberrant morphologies in the appendages, compound eye, and bristles. These aberrations were suppressed by elevated MEK activity. Structural and transgenic analyses of the lace cDNA have revealed that the lace gene product is a membrane protein similar to the yeast protein LCB2, a subunit of serine palmitoyltransferase (SPT), which catalyzes the first step of sphingolipid biosynthesis. In fact, SPT activity in the fly expressing epitope-tagged Lace was absorbed by epitope-specific antibody. The number of dead cells in various imaginal discs of a lace hypomorph was considerably increased, thereby ectopically activating c-Jun N-terminal kinase (JNK), another MAPK. These results account for the adult phenotypes of the lace mutant and suppression of the phenotypes by elevated MEK activity: we hypothesize that mutation of lace causes decreased de novo synthesis of sphingolipid metabolites, some of which are signaling molecules, and one or more of these changes activates JNK to elicit apoptosis. The ERK pathway may be antagonistic to the JNK pathway in the control of cell survival.

Acyltransferases↗

PubMed1999

Regulation of the genes for arginase isoforms and related enzymes in mouse macrophages by lipopolysaccharide.

Arginase exists in two isoforms, the hepatic (arginase I) and extrahepatic types (arginase II). Arginase I is markedly induced in rat peritoneal macrophages and rat tissues in vivo by bacterial lipopolysaccharide (LPS). In contrast, both arginase I and arginase II are induced in LPS-activated mouse peritoneal macrophages. In the present study, expression of arginase isoforms and related enzymes was studied in mouse tissues in vivo and in peritoneal macrophages with RNA blot and immunoblot analyses and enzyme assay. When mice were injected intraperitoneally with LPS, inducible nitric oxide synthase (iNOS) and arginase II were induced early in the lung and spleen. mRNAs for argininosuccinate synthase (AS) and ornithine decarboxylase (ODC) were also induced early. In comparison, arginase I was induced later in the lung. Early induction of iNOS, arginase II, AS, ODC, and cationic amino acid transporter 2 and late induction of arginase I were observed in LPS-activated peritoneal macrophages. These results indicate that the genes for the two arginase isoforms are regulated differentially. Possible roles of the arginase isoforms in the regulation of nitric oxide production and in polyamine synthesis are discussed.

Animals↗