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N Itoh

Publications and source records attributed to N Itoh.

At least 73 records · Page 4Linked to original sources
PubMed2001

Na+/H+ exchange inhibitor SM-20220 improves endothelial dysfunction induced by ischemia-reperfusion.

Endothelial cells play an important role in the physiologic homeostasis of the cerebral circulation. Previously, we showed that the Na+/H+ exchanger (NHE) inhibitor SM-20220 (N-(aminoimino-methyl)-1-methyl-1H-indole-2-carboxamide methanesulfonate) improved ischemic brain injury. In this study, we investigated the effect of SM-20220 on cerebrovascular dysfunction after ischemia-reperfusion, focusing on the kinds of dysfunction that involved endothelial function. In cultured bovine brain microvascular endothelial cells (BBMCs), the IC50 value for the NHE activity of SM-20220 was 4 x 10(-8) M. SM-20220 also reduced the cell injury induced by hypoxia/aglycemia-reoxygenation in BBMCs, with statistical significance at 10(-7) M (P<0.05). Next, the effect of SM-20220 on disruption of the blood-brain barrier and cerebral blood flow were evaluated using transient middle cerebral artery (MCA) occlusion models. Intravenous infusion of SM-20220 (0.4 mg/kg per hour for 1 h) attenuated the extravasation of Evans blue, a blood-brain barrier disruption indicator, into cerebral tissue on the day after transient ischemia (P<0.05). The occlusion of the MCA decreased the cerebral blood flow in the MCA territory by about 20%, and only about 45% of the preischemic value was recovered at 1-h reperfusion. A bolus injection of SM-20220 (1 mg/kg, i.v.) improved the postischemic hypoperfusion by about 75%, without causing changes in the systemic blood pressure. These results indicate that the protective effect of NHE inhibitor on ischemic brain injury may be at least partially mediated by the prevention of endothelial dysfunction.

Amides↗
PubMed2001

Cloning of a gene cluster encoding enzymes responsible for the mevalonate pathway from a terpenoid-antibiotic-producing Streptomyces strain.

A gene cluster encoding enzymes responsible for the mevalonate pathway was isolated from Streptomyces griseolosporeus strain MF730-N6, a terpenoid-antibiotic terpentecin producer, by searching a flanking region of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase gene, which had been previously isolated by complementation. By DNA sequencing of an 8.9-kb BamHI fragment, 7 genes encoding geranylgeranyl diphosphate synthase (GGDPS), mevalonate kinase (MK), mevalonate diphosphate decarboxylase (MDPD), phosphomevalonate kinase (PMK), isopentenyl diphosphate (IPP) isomerase, HMG-CoA reductase, and HMG-CoA synthase were suggested to exist in that order. Heterologous expression of these genes in E. coli and Streptomyces lividans, both of which have only the nonmevalonate pathways, suggested that the genes for the mevalonate pathway were included in the cloned DNA fragment. The GGDPS, MK, MDPD, PMK, IPP isomerase, and HMG-CoA synthase were expressed in E. coli. Among them, the recombinant GGDPS, MK, and IPP isomerase were confirmed to have the expected activities. This is the first report, to the best of our knowledge, about eubacterial MK with direct evidence.

Alkyl and Aryl Transferases↗
PubMed2001

Purification and characterization of a monohalomethane-producing enzyme S-adenosyl-L-methionine: halide ion methyltransferase from a marine microalga, Pavlova pinguis.

A monohalomethane-producing enzyme, S-adenosyl-L-methionine-dependent halide ion methyltransferase (EC 2.1.1.-) was purified from the marine microalga Pavlova pinguis by two anion exchange, hydroxyapatite and gel filtration chromatographies. The methyltransferase was a monomeric molecule having a molecular weight of 29,000. The enzyme had an isoelectric point at 5.3, and was optimally active at pH 8.0. The Km for iodide and SAM were 12 mM and 12 microM, respectively, which were measured using a partially purified enzyme. Various metal ions had no significant effect on methyl iodide production, suggesting that the enzyme does not require metal ions. The enzyme reaction strictly depended on SAM as a methyl donor, and the enzyme catalyzed methylation of the I-, Br-, and Cl- to corresponding monohalomethanes and of bisulfide to methyl mercaptan.

Chromatography↗
PubMed2001

Relationship between serum TNF activity and insulin resistance in dairy cows affected with naturally occurring fatty liver.

To clarity the relationship between tumor necrosis factor (TNF) and insulin resistance in dairy cows affected with fatty liver, naturally occurring cases were investigated. The affected cows were classified into following three groups according to histopathologic findings of the liver: mild fat droplet deposition (group 1; n=11), severe fat droplet deposition (group 2; n=10), and cloudy swelling (group 3; n=8). Serum TNF activities in Group 2 (8.67 +/- 2.16 U/ml) and Group 3 (11.65 +/- 1.92 U/ml) were significantly higher than that in Group 1 (3.57 +/- 0.81 U/ml) (p<0.05). The insulin-tolerance tests showed that the insulin-stimulated glucose disposal rates (GDR) in Group 2 (27.6 +/- 7.8%) and Group 3 (15.8 +/- 9.1%) were significantly lower than that in Group 1 (41.7 +/- 9.8%). There was a significant negative correlation between serum TNF activity and GDR in affected cows (r=-0.56, p<0.01). These results indicate that serum TNF activity is correlated with insulin resistance in cows with fatty liver.

Animals↗
PubMed2001

Insulin and somatostatin releasing islet cell tumor caused hypoglycemia.

We report a hypoglycemic case with normal insulin levels, which was caused by an islet cell tumor that was releasing insulin and somatostatin. A fasting test suggested the over secretion of insulin. Moreover, this hypoglycemia was enhanced by the inhibitory effect of somatostatin on the secretion of insulin counter-regulatory hormones, such as glucagon, in addition to the autonomous secretion of insulin from the tumor. In cases of hypoglycemia with apparently normal insulin levels, the measurement of somatostatin and various provocative tests are recommended. Arterial stimulation venous sampling (ASVS) was useful to detect the location of this functioning islet cell tumor.

Adenoma, Islet Cell↗
PubMed2001

Duodenal somatostatinoma and erythrocytosis in a patient with von Hippel-Lindau disease type 2A.

A female with von Hippel-Lindau (VHL) disease type 2A first presented with erythrocytosis at the age of 9 years. This patient revealed multiple paragangliomas at age 22. After the removal of tumors, a retinal hemangioblastoma developed. Our diagnosis of VHL disease type 2A was confirmed. Moreover, systemic examination showed a duodenal somatostatinoma. Frequent and long-term monitoring is important for patients with pheochromocytomas or paragangliomas, and a screening for VHL disease and other hereditary cancer syndromes is recommended. Recognition of neuroendocrine tumors as a manifestation of VHL disease permits earlier diagnosis and improves prognosis.

Adult↗
PubMed2001

IgA-kappa type multiple myeloma affecting proximal and distal renal tubules.

A 45-year-old male was admitted because of chest pain, lumbago, and bilateral ankle pain. Examination disclosed hypophosphatemic osteomalacia, acquired Fanconi syndrome, and abnormalities in distal nephron such as distal renal tubular acidosis and renal diabetes insipidus. Further exploration revealed IgA kappa multiple myeloma excreting urinary Bence Jones protein (kappa-light chain). Renal biopsy revealed thick basement membranes and elec-tron-dense crystals in proximal tubular epithelial cells. Immunofluorescent studies revealed deposition of kappa-light chain in renal tubular epithelial cells that caused the renal tubular damage. Although the osteomalacia was relieved by medical treatment, the urinary Bence Jones protein and the renal tubular defects were not improved by the chemotherapy for the myeloma. The patient died of exacerbation of multiple myeloma at 50 years of age.

Biopsy↗
PubMed2001

Pancreatic biopsy as a procedure for detecting in situ autoimmune phenomena in type 1 diabetes: close correlation between serological markers and histological evidence of cellular autoimmunity.

To better understand the pathogenesis of type 1 diabetes, we have developed pancreatic biopsy under laparoscope for recent-onset type 1 diabetic patients. The patients included 29 acute-onset type 1 diabetic patients, 5 latent-onset type 1 diabetic patients, and 1 type 2 diabetic patient. Their median age was 28 years, and the duration of diabetes at the time of biopsy was approximately 3 months. In 31 of 35 patients, we could obtain the pancreas tissue by punching. No serious complications, such as heavy bleeding, peritonitis, or pancreatitis, have been experienced. Pneumoderma was observed in two patients, and abdominal dull pain had continued for 2 days in two patients. However, special treatment was not necessary for these complications. T-cell-predominant infiltration to islets (insulitis) and hyperexpression of major histocompatibility complex class I antigens on islet cells were the two major findings and were observed in 17 of 29 recent-onset type 1 diabetic patients. These findings could be regarded as evidence of immune attack against beta-cells, and their presence was closely correlated with the presence of either anti-GAD or anti-IA-2 antibodies (P = 0.02). In conclusion, pancreatic biopsy under laparoscope is a safe procedure without serious complications, according to our findings, for detecting in situ autoimmune phenomenon in recent-onset type 1 diabetic patients.

Adolescent↗
PubMed2001

An experimental consideration of fixation properties.

While varying the size and complexity of a stimulus object, we measured eye movements during fixation. Although subjects' eyes are fixated at the center of the object, the experimental results indicate that "fluctuation during fixation (FDF)" which is larger movements than "miniature eye movements" occurred. In addition, FDF varies according to the peripherals of fixation points characterized by the size and complexity of the stimulus object.

Adult↗
PubMed2001

The effect of an Na+/H+ exchange inhibitor, SM-20550, on ischemia/reperfusion-induced endothelial dysfunction in isolated perfused rat hearts.

The aim of this study was to test the protective effect of an Na+/H+ exchange (NHE) inhibitor, SM-20550, on ischemia/reperfusion-induced endothelial dysfunction. Isolated rat hearts were subjected to 30 min of global ischemia followed by 20 min of reperfusion and their responses to the endothelial-dependent vasodilator, acetylcholine, and the endothelial-independent vasodilator, nitroglycerin, before and after ischemia were examined. Acetylcholine-induced relaxation was impaired after ischemia/reperfusion while nitroglycerin induced relaxation was not. Administration of 1-10 nmol/l SM-20550 [N-(aminoiminomethyl)-1,4-dimethyl-1H-indole-2-carboxamide methanesulfonic acid] before and after ischemia prevented impairment of acetylcholine-induced relaxation. To further understand the mechanism of SM-20550 in protecting endothelial function, we measured the inhibitory activity of SM-20550 on NHE in cultured endothelial cells. SM-20550 (1-100 nmol/l) inhibited recovery from acidosis induced by an NH4Cl prepulse in a concentration-dependent manner. Oxygen radicals from endothelial cells and leukocytes are one of the major sources of endothelial cell injury during ischemia and reperfusion. Consequently, we tested the effect of SM-20550 on H2O2-induced endothelial cell injury. SM-20550 (100-1,000 nmol/l) prevented H2O2-induced cell injury measured by lactate dehydrogenase assay. In conclusion, SM-20550 inhibited NHE in endothelial cells, protected ischemia/reperfusion-induced endothelial dysfunction and prevented H2O2-induced endothelial cell injury at higher concentrations.

Amidines↗
PubMed2001

[Elderly-onset anticentromere antibody-positive pulmonary-renal syndrome: report of an autopsy case].

We report an autopsy case of elderly-onset anticentromere antibody-positive pulmonary-renal syndrome. An 84-year-old woman was admitted to our hospital with complaints of leg edema and general malaise. Neither skin rush nor arthritis was seen. Because of hematuria, proteinuria with various casts, renal dysfunction and anemia, a clinically diagnosis of rapidly progressive glomerulonephritis was made. Slight pulmonary hypertension was observed in ultrasonic cardiography. Hypocomplementemia was not seen. Tests for MPO- and PR 3-anti-neutrophil cytoplasmic antibodies and anti-glomerular basement membrane antibody were negative, but a high titer of antinuclear antibody with a discrete speckled pattern on immunofluorescent staining was disclosed. Results for anticentromere antibody and anti-Ki antibody were positive, but for anti-Sm antibody and anti-double stranded DNA antibody were both negative. She did not present any clinical features of systemic sclerosis or CREST syndrome. Subsequently, prednisolone was administered, but pulmonary alveolar hemorrhage occurred and the patient died of acute respiratory failure caused by massive pulmonary hemorrhage. Autopsy revealed crescentic glomerulonephritis including glomerular capillaritis and pulmonary capillaritis with positive granular deposits of immunoglobulins and compliment on the glomerular and pulmonary capillary walls. Immunologically mediated crescentic glomerulonephritis and pulmonary capillaritis was then diagnosed histopathologically. The main pathological feature of the case was small-vessel vasculitis with immune-complex deposition. Although this case did not fulfill the clinical criteria for systemic lupus erythematosus (SLE), its histological features resembled those of lupus nephritis and acute lupus pneumonitis. We speculated that anticentromere antibody-positive pulmonary-renal syndrome without any other symptoms or signs of connective tissue disease, such as our case, is a clinical entity distinct from typical SLE or CREST syndrome.

Aged↗
PubMed2001

New genome type of adenovirus serotype 19 causing nosocomial infections of epidemic keratoconjunctivitis in Japan.

Twelve strains of adenovirus serotype 19, isolated from cases of epidemic keratoconjunctivitis in Japan in 1992, 1993, 1997, and 1998, were analyzed by DNA restriction analysis, using restriction endonucleases BamHI, BglI, BglII, EcoRI, HindIII, KpnI, PstI, SacI, SalI, SmaI, and XhoI. Among these 11 restriction endonucleases, EcoRI, PstI, SacI, and SmaI were discriminative enzymes, showing restriction patterns different from those reported previously for the prototype and the variant 19a. This new genome type was isolated in 1997 and 1998, when an increase of epidemic keratoconjunctivitis cases caused by adenovirus serotype 19 was observed for both sporadic and nosocomial infections. Strains from 1992 and 1993 showed restriction patterns similar to those of the worldwide reported variant 19a for all enzymes used. The changes detected in strains from 1997 and 1998 could be the reason for the recent epidemic.

Adenovirus Infections, Human↗
PubMed2001

[Evaluation of central retinal sensitivity after vitrectomy with removal of choroidal neovascular membrane for age-related macular degeneration].

PURPOSE: To evaluate retinal sensitivity in patients with age-related macular degeneration (AMD) before and after surgery. METHODS: Seven consecutive patients with AMD underwent vitrectomy with removal of choroidal neovascular membrane(CNV). Static microperimetry using a scanning laser ophthalmoscope(SLO) was performed before and after surgery. Central dense scotoma size was measured. RESULTS: Retinal sensitivity improved in all cases. Mean size of the central dense scotoma was decreased by 42%(range 14-62%). CONCLUSION: The results suggest that vitrectomy with removal of CNV can improve the central retinal sensitivity.

Aged↗
PubMed2001

[Transurethral endoscopic treatment for chronic hematospermia caused by müllerian duct cyst and ejaculatory duct obstruction].

Between June 1997 and September 1999, we performed transurethral unroofing (TUUR) in three patients with hematospermia that recurred repeatedly for one year or more. Patient 1 (48 years old) and Patient 2 (59 years old) were diagnosed as having müllerian duct cysts that communicated with the left ejaculatory duct, and Patient 3 (36 years old) as an ejaculatory duct obstruction with the right ejaculatory duct dilation. A mixture of water-soluble contrast medium and indigocarmine blue dye was injected into the cysts and the ejaculatory duct cavity after incision of the vas deferens in Patients 1 and 3, and by cyst puncture under transrectal ultrasound (TRUS) guidance in Patient 2. Then the urethra was incised between the bladder neck and the verumontanum using a Collins' hot knife electrode, and spouting of the dye from the incision was judged to indicate successful unroofing. In Patient 2, safe and simple TUUR was possible by identifying the cyst location and its distance from the knife electrode under TRUS guidance. Hematospermia resolved after surgery in all three patients and there has been no recurrence for 1.3-3.5 years (mean: 2.6 years). Thus, TUUR was effective for treating chronic hematospermia caused by müllerian duct cyst and ejaculatory duct obstruction. For safe and reliable performance of this treatment, TRUS guidance and injection of the dye into the cyst and ejaculatory duct cavity can be recommended.

Adult↗
PubMed2001

[The prediction of bladder outlet obstruction with prostate volume, maximum flow rate, residual urine and the international prostate symptom score in patients with lower urinary tract symptoms].

We determined whether prostate volume (PV), maximum flow rate (Qmax), residual urine (RU) and the International Prostate Symptom Score (I-PSS) predicted bladder outlet obstruction in patients having lower urinary tract symptoms (LUTSs). The study consisted of 114 patients aged 50 years or older with LUTSs who had scores of 8 or more on the I-PSS and 2 or more for the quality of life index. All patients received transrectal ultrasonography for estimation of PV and pressure-flow study (PFS). When PFS showed an obstruction grade of 2 or more in Schäfer's p/Q diagram, the result was defined as bladder outlet obstruction. When we examined which criteria indicated that 90% of patients had bladder outlet obstruction (positive predictive value: 90%), we found that PV of 35 ml or more, Qmax of 8 ml/sec or less, RU of 110 ml or more, and I-PSS of 30 or more did so. Fifty-nine percent of patients met at least one of these criteria. The results suggested that 59% of patients with LUTSs had bladder outlet obstruction with a 90% positive predictive value based on the value of PV, Qmax, RU or I-PSS.

Aged↗
PubMed2000

FGF10 acts as a major ligand for FGF receptor 2 IIIb in mouse multi-organ development.

FGF receptor 2 isoform IIIb (FGFR2b), originally discovered as a receptor for FGF7, is known to be an important receptor in vertebrate morphogenesis, because FGFR2b null mice exhibit agenesis or dysgenesis of various organs, which undergo budding and branching morphogenesis. Since FGF7 null mice do not exhibit marked defects in organogenesis, it has been considered that other FGF(s) than FGF7 might function as a major ligand for FGFR2b during organogenesis. One of the candidate ligands is FGF10, because FGF10 binds to FGFR2b with high affinity and the formation of the limb and lung is arrested in FGF10 null mice as found in FGFR2b-deficient mice. Previous analyses of FGF10 null mice revealed that FGF10 is required for limb and lung development. To elucidate the role of FGF10 in wide-range organogenesis, we further analyzed the phenotypes of the FGF10 knockout mice. We found diverse phenotypes closely related to those for FGFR2b-deficient mice, which includes the absence of thyroid, pituitary, and salivary glands, while minor defects were observed in the formation of teeth, kidneys, hair follicles, and digestive organs. These results suggest that FGF10 acts as a major ligand for FGFR2b in mouse multi-organ development.

Animals↗
PubMed2000

FGF-20, a novel neurotrophic factor, preferentially expressed in the substantia nigra pars compacta of rat brain.

We have isolated cDNA encoding a novel FGF (212 amino acids) from rat brain. Because this is the 20th documented member of the FGF family, we tentatively term it FGF-20. Among FGF family members, FGF-20 is most similar to FGF-9 and FGF-16 (70 and 62% amino acid identity, respectively). Human FGF-20 gene was found in the human genomic sequence mapped to the 8p21.3-p22 region. Human FGF-20 is highly identical to rat FGF-20 (95% amino acid identity). FGF-20 mRNA was preferentially expressed in rat brain among the adult major tissues examined. The localization of FGF-20 mRNA in rat brain was also examined by in situ hybridization. FGF-20 mRNA was preferentially expressed in the substantia nigra pars compacta. To examine the biological activity of FGF-20, recombinant rat FGF-20 was produced by insect cells infected with recombinant baculovirus containing rat FGF-20 cDNA. Recombinant rat FGF-20 enhanced the survival of midbrain dopaminergic neurons. The present results indicate that FGF-20 is a novel neurotrophic factor preferentially expressed in the substantia nigra pars compacta of rat brain.

Amino Acid Sequence↗