Biomedical subjects

N Itoh

Publications and source records attributed to N Itoh.

At least 163 records · Page 9Linked to original sources

PubMed1999

FGF10 can induce Fgf8 expression concomitantly with En1 and R-fng expression in chick limb ectoderm, independent of its dorsoventral specification.

The limb bud has a thickened epithelium at the dorsal-ventral boundary, the apical ectodermal ridge (AER), which sustains limb outgrowth and patterning. A secreted molecule fibroblast growth factor (FGF)10 is involved in inducing Fgf8 expression in the prospective AER and mutual interaction between mesenchymal FGF10 and FGF8 in the AER is essential for limb outgrowth. A secreted factor Wnt7a and a homeobox protein Lmx1 are involved in the dorsal patterning of the limb, whereas a homeobox protein Engrailed 1 (En1) is involved in the dorsal-ventral patterning as well as AER formation. Radical fringe (R-fng), a vertebrate homolog of Drosophila fringe was also found to elaborate AER formation in chicks. However, little is known about the molecular interactions between these factors during AER formation. The present study clarified the relationship between FGF10, Wnt7a, Lmx1, R-fng and En1 during limb development using a foil-barrier insertion experiment. It was found that a foil-barrier inserted into the chick prospective wing mesenchyme lateral to the mesonephric duct blocks AER induction. This experiment was expanded by implanting Fgf10-expressing cells lateral to the barrier and examined whether FGF10 could rescue the expression of the limb-patterning genes reported in AER formation. It was found that FGF10 is sufficient to induce Fgf8 expression in the ectoderm of the foil-inserted limb bud, concomitantly with R-fng and En1 expression. However, FGF10 could not rescue the expression of the dorsal marker genes, Wnt7a or Lmx1. Thus, it is suggested that epithelial factors of En1 and R-fng can induce Fgf8 expression in the limb ectoderm in cooperation with a mesenchymal factor FGF10. Some factor(s) other than FGF10, possibly from the paraxial structures medial to the limb mesoderm, is responsible for the initial dorsal-ventral specification of the limb bud.

Animals↗

PubMed1999

Quality of life in patients having an ileal conduit, continent reservoir or orthotopic neobladder after cystectomy for bladder carcinoma.

BACKGROUND: To compare the QOL in patients with ileal or colon conduits (IC), continent urinary reservoir (CR) and ileal neobladder (NB), a retrospective study was conducted using a questionnaire sent by mail. METHODS: Seventy-nine patients with a mean age of 60 years were included in this study. A total of 36, 22 and 21 underwent IC, CR and NB, respectively and were alive at the time of this study. A structured questionnaire consisting of 97 questions that covered general condition and physical condition, reconstruction-related symptoms, psychological status, sexual life, social status and satisfaction with the treatment was employed. RESULTS: The IC group frequently complained of changes in bathing habits and loss of using public baths in comparison with the CR and the NB groups. High scores for loss of sexual desire were obtained in the IC, the CR and the NB groups, in this order. Because of the nearly physiological voiding, the NB group desired a voiding condition like pre-operative status as compared with the IC and the CR groups. However, for most of the questionnaire items no difference was seen among the IC, CR and NB groups concerning general condition, reconstruction-related symptoms, psychological status, sexual life, social status, satisfaction with the treatment and global satisfaction with life and health. CONCLUSIONS: There was little difference in the QOL score of the questionnaire and satisfaction among the IC, CR and NB groups. It was suggested that almost every patient accepted and adapted to the present status of general quality of life in each group.

Adult↗

PubMed1999

p53 overexpression and mutation in endometrial carcinoma: inverted relation with estrogen and progesterone receptor status.

Overexpression and mutation of p53 in 46 primary endometrial carcinomas were determined comparatively with the status for estrogen receptor (ER) and progesterone receptor (PR). Immunohistochemically p53 overexpression was found in 9 of 46 cases (20%), while eight kinds of mutations in that gene were detected in 7 of 46 endometrial carcinomas (15%), using polymerase chain reaction single-strand conformation polymorphism and subsequently direct sequencing method. Six of nine cases with p53 overexpression showed p53 mutation. All eight mutations showed single substitutions, and three cases in exon 4, one in exon 5, two in exon 6, and two in exon 7 were found. The cases with the p53 overexpression were significantly inversely related to that of ER or PR staining. Most endometrial carcinoma with p53 overexpression and/or mutation had a relatively poor prognosis and showed no reactivities of ER or PR.

Adult↗

PubMed1999

Capillary blood flow velocity in patients with idiopathic epiretinal membranes.

PURPOSE: Eyes with idiopathic epiretinal membranes (ERM) often have tortuous vessels and macular edema, suggesting that eyes with ERM may have a disturbance of the macular microcirculation. The authors studied perifoveal microcirculation in eyes with ERM by means of scanning laser ophthalmoscope (SLO) fluorescein angiography. METHODS: Mean capillary blood flow velocity (CFV) was measured by SLO fluorescein angiography in 19 eyes with ERM before and 6 months after vitreous surgery and in 19 healthy control eyes. RESULTS: Mean CFV was significantly reduced in the eyes with ERM compared with the healthy control eyes (2.98 +/- 0.32 mm/sec versus 3.34 +/- 0.12 mm/sec, P < 0.05), and postoperative mean CFV was significantly increased compared with preoperative mean CFV (3.14 +/- 0.32 mm/sec versus 2.98 +/- 0.32 mm/sec, P < 0.05). CONCLUSIONS: Eyes with ERM show abnormal hemodynamics in the perifoveal capillaries. Surgical treatment of eyes with ERM results in improvement of the abnormal blood flow.

Blood Flow Velocity↗

PubMed1999

Adenovirus strains of subgenus D associated with nosocomial infection as new etiological agents of epidemic keratoconjunctivitis in Japan.

Adenovirus strains of a new type were isolated from patients with epidemic keratoconjunctivitis. They were not completely neutralized by any antiserum against adenovirus prototypes. PCR followed by restriction endonuclease analysis demonstrated that they were type 8. PCR followed by sequencing revealed a high homology rate between them and type 9.

Adenoviridae↗

PubMed1999

Serotyping of adenoviruses on conjunctival scrapings by PCR and sequence analysis.

To detect and identify adenovirus (Ad), we investigated hypervariable regions (HVRs) of Ad by using a combination of PCR and direct sequencing (PCR-sequence) method. Primers for nested PCR to amplify the conserved region in the hexon protein containing HVRs were designed based on hexon gene sequences derived from GenBank. These two primer sets amplified a DNA fragment of 7 HVRs from 16 prototypes of Ad, which were divided into five subgenera, including seven serotypes that are the predominant causative agents of acute conjunctivitis in Japan, and from 31 recent conjunctival scraping specimens from patients with adenoviral conjunctivitis. HVR DNA sequences were determined by means of universal sequence primers. Analysis of the predicted amino acid homology of HVRs among Ad prototypes suggested three regions, HVR4, -5, and -7, to be candidates for the neutralization epitopes. The clinical serotype of specimens was determined by the PCR-sequence method with reference to these three HVRs. The serotype determined according to this method was identical to that obtained by culture isolation and the neutralization test (NT) in all scraping samples, whereas the results of this method did not match PCR and restriction fragment length polymorphism (PCR-RFLP) analysis in five samples. It took only three days to detect Ad and to identify the serotype, in contrast to culture isolation-NT, which took at least 2 weeks. These findings indicate that our newly developed PCR-sequence method is applicable for the detection and serotyping of human Ads.

Adenovirus Infections, Human↗

PubMed1999

Perifoveal microcirculation in eyes with epiretinal membranes.

BACKGROUND/AIMS: Eyes with epiretinal membranes (ERMs) often have alterations of retinal vessels. The authors studied perifoveal microcirculation in eyes with epiretinal membranes (ERMs) using scanning laser ophthalmoscope (SLO) fluorescein angiography. METHODS: Mean capillary blood flow velocity (CFV) was measured as an index of perifoveal microcirculation by SLO fluorescein angiography in 26 eyes with ERMs (19 eyes with idiopathic epiretinal membranes, seven eyes with epiretinal membranes after retinal detachment surgery) before and 6 months after vitreous surgery, and in 23 healthy control subjects. RESULTS: The mean CFV was significantly reduced in eyes with ERMs compared with healthy controls (p=0.012), and the postoperative mean CFV was significantly increased compared with the preoperative mean CFV (p=0.041). CONCLUSION: Significant changes of capillary blood flow velocity in the perifoveal areas were observed between normal subjects and eyes with epiretinal membranes. This indicates that eyes with ERMs show abnormal haemodynamics in the perifoveal capillaries.

Adult↗

PubMed1999

Preexisting membranous nephropathy in allograft kidney.

A case of membranous nephropathy, preexisting in a donor kidney, will be reported. A 41-year-old man underwent a cadaver renal transplantation. An allograft biopsy specimen obtained during the operation showed spike formation on periodic acid-silver methenamine staining and deposition of IgG along the glomerular capillary loop on immunoperoxidase staining. Immunofluorescence staining for IgG remained in the specimens obtained on day 11 and after 4 weeks, but markedly decreased in the specimen obtained 7 weeks after transplantation. Electron-dense deposits also decreased in amount, but irregular thickening of the glomerular basement membrane with spikes, electron-lucent washout lesions, and small amounts of electron-dense deposits remained 20 months after the transplantation. These findings suggest that membranous nephropathy, as well as IgA nephritis and diabetic nephropathy, resolve after renal transplantation and that deposition of IgG markedly decreases within a few months after transplantation, but that complete histological restoration of the basement membrane needs at least a few years.

Adult↗

PubMed1999

A comparative study of the repeat dose toxicity of grepafloxacin and a number of other fluoroquinolones in rats.

Grepafloxacin is a new oral fluoroquinolone with potent activity against community acquired respiratory pathogens, including Streptococcuspneumoniae, and pharmacokinetic properties which allow once daily dosing. As part of its safety evaluation a study of 4 weeks duration was performed to compare the toxicity of grepafloxacin with that of a number of commercially available quinolones in the rat. Groups of eight male Sprague-Dawley rats received either control material or grepafloxacin, enoxacin, lomefloxacin, ofloxacin or ciprofloxacin at an oral dosage of 300 mg/kg/day for 4 consecutive weeks. Effects related to the antibacterial activity of the drugs were seen as increased caecal weight, decreased urinary excretion of sodium, increased water consumption, decreased urine volume, increased urine osmolality, soft stools and suppressed body weight gain. It is well documented that fluoroquinolones can cause lesions in the cartilage of the major diarthrodial joints, and blister formation or erosion on the joint surface was observed in all quinolone-treated groups other than the grepafloxacin group. Some quinolones, have been found to cause crystalluria, which is often associated with secondary nephropathy in laboratory animals due to the poor solubility of quinolones under the alkaline conditions of the urine. In the present study, needle-like crystals in the urinary sediment were observed in enoxacin and ciprofloxacin treated groups only. In conclusion, grepafloxacin was well tolerated and showed a low potential for joint toxicity and crystalluria compared to other quinolones.

Animals↗

PubMed1999

Site-directed mutagenesis of two zinc-binding centers of the NADH-dependent phenylacetaldehyde reductase from styrene-assimilating Corynebacterium sp. strain ST-10.

Phenylacetaldehyde reductase (PAR) with a unique and wide substrate range from styrene-assimilating Corynebacterium sp. strain ST-10, which is a useful biocatalyst producing chiral alcohols, has been found to belong to a family of zinc-containing, long-chain alcohol dehydrogenases (ADHs) on the basis of the primary structure similarity. The enzyme contains 2 moles of zinc per mole of subunit. The amino acid residues assumed to be three catalytic and four structural zinc-binding ligands were characterized by site-directed mutagenesis, compared with other zinc-containing, long-chain ADHs. Sixteen PAR mutants gave measurable but rather low activities toward phenylacetaldehyde, n-hexyl aldehyde, and 2-heptanone, although they maintained the activities of 8 to 16% of that of wild-type PAR for an acetophenone substrate except that the D153N mutant showed quite low activity. The results suggested that the seven residues present in PAR were probably zinc-binding ligands, and mutation in these residues caused a change in activities for some substrates.

Alcohol Oxidoreductases↗

PubMed1999

Androgen-stimulated human prostate epithelial growth mediated by stromal-derived fibroblast growth factor-10.

It has been suggested that prostate homeostasis is regulated indirectly by androgens through stromal-epithelial interactions in part by factors from the stromal cells acting on receptors in epithelial cells. In this report, the role of fibroblast growth factor (FGF)-10 in prostatic epithelial proliferation was investigated. The expression of FGF-10 mRNA was apparent in primary-cultured stromal cells, but not in epithelial cells derived from human tissue from patients with benign prostatic hyperplasia (BPH). The mitogenic activity of human recombinant FGF-10 assessed by 5-bromo-2'-deoxyuridine (BrdU) incorporation was demonstrated in isolated epithelial cells, but not in cultured stromal cells. No mitogenic activity of dihydrotestosterone (DHT) for either epithelial or stromal cells could be demonstrated, but quantitative PCR (real-time PCR) with a double-labeled fluorogenic probe demonstrated that expression of FGF-10 in stromal cells was enhanced 5.3-fold at a DHT concentration of 100 pM. Androgen receptor mRNA levels showed no significant change with DHT at concentrations less than 100 pM, but were reduced to 50% of control levels at a DHT concentration of 10 nM. These results suggest that stromal-derived FGF-10 stimulates human prostatic epithelial growth and its mRNA expression is induced by androgens, without an increase in the androgen receptor mRNA. Moreover, FGF-10 may be involved in the development or support of human BPH.

Androgens↗

PubMed1999

Vasospastic angina likely related to cisplatin-containing chemotherapy and thoracic irradiation for lung cancer.

Vasospastic angina is rarely observed during cancer treatment. The present report describes two males with lung cancer, aged 73 and 61, who developed vasospastic angina during combination treatment of cisplatin-containing chemotherapy and thoracic irradiation. As both patients have smoked and their ages are typical for patients with coronary artery disease, such events may be incidental. However, oncologists should be aware of the possible development of myocardial ischemia during or following administration of antineoplastic agents, especially in elderly patients with pre-existing coronary risk factors or a history of thoracic radiotherapy.

Adenocarcinoma↗

PubMed1999

[Correlation of risk area and reverse redistribution of 99mTc-sestamibi SPECT in acute myocardial infarction following direct PTCA].

Redistribution of 99mTc-sestamibi is negligible in usual circumstances, but recent reports demonstrated reverse redistribution is detectable in acute myocardial patients. Correlation of risk area, observed in 99mTc-sestamibi "freezed" SPECT image at onset, and delayed images at 5-25 days after onset (post-PTCA image) is evaluated in 19 acute myocardial infarction patients treated with direct PTCA. Reverse redistribution was observed in 85% of reperfused area. Linear relationship of % uptake in each SPECT segment between onset and post-PTCA images (taken at 0.5, 4, and 6 hours after injection) is evaluated and the relationship improves over time course. The correlation coefficient between onset and 6 hours-delayed image is 0.88, and the visual concordance shows 77% of score matching. Delayed 99mTc-sestamibi SPECT image on reperfused AMI seems to represent risk area with some underestimation. It may be useful to estimate both risk and salvaged areas on early and delayed SPECT with a single 99mTc-sestamibi injection.

Adult↗

PubMed1999

Induction of apoptosis by hinokitiol, a potent iron chelator, in teratocarcinoma F9 cells is mediated through the activation of caspase-3.

Hinokitiol, a potent iron chelator, has been reported to induce differentiation in teratocarcinoma F9 cells with a reduction of viable cells. In this study, we examined the steps leading to eventual cell death by hinokitiol during differentiation. Hinokitiol induced DNA fragmentation of F9 cells in a concentration- and time-dependent manner. This effect was also observed in a cell-free system using the nuclei from intact cells and the cytosols from hinokitiol-treated cells. In contrast, hinokitiol methyl ether and hinokitiol-Fe (III) complex, which are deficient in iron-chelating activity, showed no DNA fragmentation activity in both cell culture and cell-free systems. These results suggest that iron deprivation by hinokitiol may be involved in the induction of apoptosis of F9 cells. Caspase-3, one of the key enzymes in the apoptotic cascade, was specifically activated by hinokitiol treatment, but not by the other two derivatives. In addition, its specific inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone, strongly blocked hinokitiol-induced DNA fragmentation. These results indicate that iron deprivation by hinokitiol can induce apoptosis of F9 cells through the activation of caspase-3.

Amino Acid Chloromethyl Ketones↗

PubMed1999

Delayed treatment of Na+/H+ exchange inhibitor SM-20220 reduces infarct size in both transient and permanent middle cerebral artery occlusion in rats.

SM-20220 (N-(aminoiminomethyl)-1-methyl-1H-indole-2-carboxamide methanesulfonate) is a Na+/H+ exchanger (NHE) inhibitor which has been shown to attenuate cerebral edema in the rat transient focal ischemia model. However, to date, the effect of SM-20220 on cerebral infarction has not been examined. The present experiments were designed to investigate these effects, using both transient and permanent middle cerebral artery (MCA) occlusion models in rats. A dose of 1 mg/kg given intravenously 30 min after the onset of transient MCA occlusion reduced the infarcted area. In the permanent MCA occlusion model, SM-20220 reduced the infarcted area when treatment was delayed for 5, 30 or 60 min after the onset of ischemia. The present results show that NHE has a crucial role in the pathogenesis of ischemic brain damage. This NHE inhibitor may be useful for treating stroke because of its effectiveness with both forms of ischemia and because of its postischemic administration.

Amides↗

PubMed1998

Tissue accumulation of cadmium following oral administration to metallothionein-null mice.

To verify the roles of intestinal metallothionein (MT) as a barrier against ingested cadmium (Cd) and as a transporter of mucosal Cd to the kidneys, the distribution of orally administered Cd was compared between normal and MT-I and -II knock-out (MT-null) mice. Following single administration of a low dose of Cd (0.1 mg/kg), hepatic Cd levels and the sum of total Cd in the liver and kidney (K + L) were significantly less in the controls than in MT-null mice. The ratio of Cd in the kidney to the liver (K/L) was significantly lower in the MT-null mice. On the other hand, at a high Cd dose (2.0 mg/kg), K + L and K/L were not significantly different between the two groups. However, following oral pretreatment with zinc (Zn) to the high dose control mice, K + L significantly decreased and K/L significantly increased. No such effects of Zn pretreatment were observed in MT-null mice. Similar differences in K + L and K/L were also observed between the control and MT-null mice groups following the Zn pretreatment. Repeated administration of Cd for 4 weeks resulted in significantly larger K/L distribution in control mice over null mice. These results suggest that MT in the intestinal mucosa functions both as a protective barrier against Cd absorption and as an extracellular transporter of Cd to the kidney.

Administration, Oral↗

PubMed1998

Structure and expression of the mRNA encoding a novel fibroblast growth factor, FGF-18.

We isolated the cDNA encoding a novel member (207 amino acids) of the fibroblast growth factor (FGF) family from rat embryos. Because this protein is the 18th documented member of the FGF family, we tentatively termed it FGF-18. We have also determined mouse and human FGF-18 with high amino acid identity (99.5 and 99.0%) to rat FGF-18, respectively. Among FGF family members, FGF-18 is most similar (52.7% amino acid identity) to FGF-8 and FGF-17. FGF-18 has a typical signal sequence at its amino terminus. Recombinant rat FGF-18, which was efficiently secreted by High Five insect cells infected with recombinant baculovirus containing the cDNA, induced neurite outgrowth in PC12 cells. The expression of FGF-18 mRNA was examined in adult rat tissues and embryos by Northern blotting analysis and in situ hybridization. FGF-18 mRNA of approximately 2. 7 kilobases was preferentially detected in the lung among adult rat tissues examined. In rat embryos, FGF-18 mRNA was detected in several discrete regions at embryonic days 14.5 and 19.5 but not at E10.5. The temporal and spatial patterns of FGF-18 mRNA expression in embryos are quite different from those of FGF-8 and FGF-17 mRNAs reported. The present results indicate that FGF-18 is a unique secreted signaling molecule in the adult lung and developing tissues.

Amino Acid Sequence↗

PubMed1998

A novel metal-activated pyridoxal enzyme with a unique primary structure, low specificity D-threonine aldolase from Arthrobacter sp. Strain DK-38. Molecular cloning and cofactor characterization.

The gene encoding low specificity D-threonine aldolase, catalyzing the interconversion of D-threonine/D-allo-threonine and glycine plus acetaldehyde, was cloned from the chromosomal DNA of Arthrobacter sp. strain DK-38. The gene contains an open reading frame consisting of 1,140 nucleotides corresponding to 379 amino acid residues. The enzyme was overproduced in recombinant Escherichia coli cells and purified to homogeneity by ammonium sulfate fractionation and three-column chromatography steps. The recombinant aldolase was identified as a pyridoxal enzyme with the capacity of binding 1 mol of pyridoxal 5'-phosphate per mol of subunit, and Lys59 of the enzyme was determined to be the cofactor binding site by chemical modification with NaBH4. In addition, Mn2+ ion was demonstrated to be an activator of the enzyme, although the purified enzyme contained no detectable metal ions. Equilibrium dialysis and atomic absorption studies revealed that the recombinant enzyme could bind 1 mol of Mn2+ ion per mol of subunit. Remarkably, the predicted amino acid sequence of the enzyme showed no significant similarity to those of the currently known pyridoxal 5'-phosphate-dependent enzymes, indicating that low specificity D-threonine aldolase is a new pyridoxal enzyme with a unique primary structure. Taken together, low specificity D-threonine aldolase from Arthrobacter sp. strain DK-38, with a unique primary structure, is a novel metal-activated pyridoxal enzyme.

Amino Acid Sequence↗