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Biomedical subjects

Y Nemoto

Publications and source records attributed to Y Nemoto.

At least 73 records · Page 4Linked to original sources

Neurofibromatosis type 1 and type 2: review of the central nervous system and related structures.

Although computed tomography (CT) provides a major imaging advance over conventional radiography and tomography in examining the whole body, the development of magnetic resonance (MR) imaging has proven to be an even greater breakthrough in diagnostic medical imaging. The anatomic detail demonstrated in a MR image is a representation of at least three physical properties of static-tissue: proton density, and T1 and T2 relaxation times. Intrinsic differences in proton density and, in particular, in proton relaxation times of tissues allow excellent image contrast between various normal structures and high sensitivity in detecting pathological states. This article discusses imaging features of neurofibromatosis, with particular emphasis on the potential of MR imaging.

Adolescent↗

Sonographic appearance of hemorrhagic ovarian cyst with acute abdomen by transvaginal scan.

Hemorrhagic ovarian cyst (HOC) which is one of the functional cysts, is often involved in acute abdomen leading to laparatomy intervention. The reason for this mainly lies in the fact that it is easily misdiagnosed as an organic mass because of the presence of lower abdominal pain and the variable appearance of ultrasonographic images at presentation. We analyzed 15 cases of HOC associated with acute abdomen, of which in 2 cases the disease was confirmed by laparotomy. The remaining 13 cases were followed-up clinically and by daily transvaginal sonography (TVS) from the first detection of the cyst until complete resolution. The TVS images showed a variety of changes; however, when the images or their magnified views were observed precisely, important diagnostic characteristics were found which were classified into 3 categories: type 1 images showed mixed hypoechoic and hyperechoic areas, the demarcation line between which appeared as a thin or thick septum-like echo of smooth formation; type 2 images showed hypoechoic background and vertical, horizontal, or lamellar thin or thick thread-like echoes with an overall reticular-like or sponge-like pattern; and type 3 images showed an overall hyperechoic and solid pattern. Type 1 and 2 images occurred more frequent (93.3%), and only 1 case had a type 3 image. In all image types, septum-like or thread-like echoes were seen, TVS type 1 and 2 images showed a clear division into hyperechoic and other areas with the passing of time which was finally changed into a cystic pattern and disappeared. Severe lower abdominal pain was present for 1 to 3 hours in 12 cases (80%), 4 to 6 hours in 2 cases (13.3%), and 11 hours in 1 case (6.7%). Other characteristics of HOC may be its most frequent occurrence in the young age group (10 to 20 years old, 80.0%) and in the luteal phase (84.6%). With operative cases, histopathological diagnosis was HOC. The clinical and particularly TVS findings described in the present study are of significant value in differential diagnosis of HOC with acute abdomen from other disorders presenting with acute abdomen.

Abdomen, Acute↗

Malignant fibrous histiocytoma of the temporal bone with endocranial extension.

Cranial malignant fibrous histiocytomas are rare tumors. Most are hypervascular, destructive masses that are similar to other malignant lesions and to malignant fibrous histiocytomas found elsewhere in the body. We describe a myxoid malignant fibrous histiocytoma of the temporal bone, possibly of dural origin, with features that more closely resembled a meningioma at CT, MR imaging, and angiography.

Adult↗

A novel therapeutic approach for rectal varices: a case report of rectal varices treated with double balloon-occluded embolotherapy.

We present a patient with continuous melena, diagnosed as rectal varices bleeding. She had a history of esophageal varices, which was treated by endoscopic ligation therapy. Eight years after the treatment of esophageal varices, the continuous melena began. Colonoscopic examination showed that the melena was caused by rectal varices, which were so severe that they could not be treated by either endoscopic sclerotherapy or surgical devascularization. Taking into considering the overall risk of treating rectal varices, we chose the approach of double balloon-occluded embolotherapy (DBOE) with 5% ethanolamine oleate with iopamodol as a liquid embolic material. DBOE is one of the interventional radiology techniques (Morita et al., Acta Hepatol Jpn 1994;35:109-120), but in this case was a completely new and novel clinical procedure for rectal varices. After the DBOE therapy, the condition of rectal varices was markedly improved. Thus, DBOE might be a new tool for treating inoperable rectal varices.

Aged↗

[A case of conjunctival mucosal neuroma without multiple endocrine neoplasia].

Non-traumatic conjunctival mucosal neuroma (CMN) is usually complicated by multiple endocrine neoplasia (MEN). We report the first case of CMN without MEN type IIb (III). A 14-year-old Japanese girl had CMN in the conjunctival fornix of right eye. CMN was diagnosed from histopathology and immunohistochemistry. T1-weighted magnetic resonance imaging (MRI) showed a circular scribed iso-intensity signal, and the T2-weighted image showed iso-or high-intensity signal. There were no abnormal findings in the tongue, the neck or the abdomen.

Adolescent↗

Disruption of three phosphatidylinositol-polyphosphate 5-phosphatase genes from Saccharomyces cerevisiae results in pleiotropic abnormalities of vacuole morphology, cell shape, and osmohomeostasis.

As a result of the genome sequencing project in Saccharomyces cerevisiae, three open reading frames were found in the yeast genome that contain sequences with strong homology to all the domains conserved among the four mammalian phosphatidylinositol-phosphate 5-phosphatases: inpp5bp, ocrl1p, synaptojanin, and ship. In addition, all three yeast gene products shared with synaptojanin regions of homology to the SAC1 gene of yeast. Disruption of each of these genes singly and in pairs produced mutant strains that were viable but demonstrated variable phenotypes of abnormal vacuolar and plasma membrane morphology as well as increased sensitivity to osmotic stress. Total phosphatidylinositol-(4,5)-bisphosphate 5-phosphatase activity was reduced to varying degrees in each of the strains. No defect in carboxypeptidase Y sorting was seen in a processing and targeting assay. Abnormal actin cytoskeleton morphology was present in some of the strains carrying mutations in two of the genes.

Amino Acid Sequence↗

Regulatory function of delta/YY-1 on the locus control region-like sequence of mouse glycophorin gene in erythroleukemia cells.

The far upstream region (-1.2-0.9 kilobase pairs) of the mouse glycophorin gene contains the locus control region (LCR)-like region, which acts as an erythroid-specific enhancer dependent on chromosomal integration in murine erythroleukemia (MEL) cells. In the present study, we demonstrated that this region binds six nuclear factors. The binding of GATA-1 to corresponding sites did not show any change before or after induction with dimethyl sulfoxide, but the binding of Spi-1/PU.l and an unidentified factor called glycophorin regulatory element binding factor (GRBF) showed a change during induction. While binding activity of Spi-l/PU.l dropped soon after induction, the GRBF activity increased after induction when expression of the glycophorin gene began. After identification of the consensus binding site of GRBF, we cloned cDNA for that factor by Southwestern method, and it was identified as a previously reported transcription factor, delta, a murine form of YY-l which is a versatile transcription factor. Mutation analysis in the delta/YY-1 binding site within the LCR-like region indicated that delta/YY-1 acts as a regulatory protein in combination with the E-box-binding protein that binds to the neighboring sequence.

Animals↗

Binding of botulinum type B neurotoxin to Chinese hamster ovary cells transfected with rat synaptotagmin II cDNA.

We have previously identified synaptotagmin, a synaptic vesicle membrane protein from rat brain, as a binding protein for Clostridium botulinum type B neurotoxin. In this report, rat synaptotagmin II was expressed by transfection in Chinese hamster ovary cells and interaction with the neurotoxin was studied. In stable transfectants, the NH(2)-terminal region of synaptotagmin was exposed to the extracellular medium. Synaptotagmin-expressing cells were shown to possess an extremely low binding activity for the radiodinated toxin. However, toxin-binding was markedly increased to cells which had been treated with gangliosides G T1b or G D1a. In synapses, the intravesicular NH(2)-terminus of synaptotagmin becomes exposed at the cell surface after following exocytosis. These findings suggest that the NH(2)-terminal domain of synaptotagmin II forms the binding site for type B neurotoxin by associating with specific gangliosides in presynaptic plasma membranes.

Animals↗

A novel fluorescent derivative of glucose applicable to the assessment of glucose uptake activity of Escherichia coli.

A novel fluorescent derivative of glucose was synthesized by reacting D-glucosamine and NBD-Cl. The TLC analysis of the reaction mixture showed the generation of a single spot with intense fluorescence (lambda Ex = 475 nm, lambda Em = 550 nm). The obtained novel fluorescent product, which was identified as 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) by 1H-NMR and FAB-MS spectrometries, was applied to the assessment of the glucose uptake activity of Escherichia coli B. 2-NBDG accumulated in living cells and not in dead cells. The uptake of 2-NBDG was competitively inhibited by D-glucose and not by L-glucose, which suggested the involvement of the glucose transporting system in the uptake of 2-NBDG. 2-NBDG taken into the cytoplasma of E. coli cells was supposedly converted into another derivative in the glucose metabolic pathway.

4-Chloro-7-nitrobenzofurazan↗

A presynaptic inositol-5-phosphatase.

Synaptojanin is a nerve terminal protein of relative molecular mass 145,000 which appears to participate with dynamin in synaptic vesicle recycling. The central region of synaptojanin defines it as a member of the inositol-5-phosphatase family, which includes the product of the gene that is defective in the oculocerebrorenal syndrome of Lowe. Synaptojanin has 5-phosphatase activity and its amino-terminal domain is homologous with the yeast protein Sac1 (Rsd1), which is genetically implicated in phospholipid metabolism and in the function of the actin cytoskeleton. The carboxy terminus, which is of different lengths in adult and developing neurons owing to the alternative use of two termination sites, is proline-rich, consistent with the reported interaction of synaptojanin with the SH3 domains of Grb2 (refs 1, 2). Synaptojanin is the only other major brain protein besides dynamin that binds the SH3 domain of amphiphysin, a presynaptic protein with a putative function in endocytosis. Our results suggest a link between phosphoinositide metabolism and synaptic vesicle recycling.

Amino Acid Sequence↗

The high-affinity binding of Clostridium botulinum type B neurotoxin to synaptotagmin II associated with gangliosides GT1b/GD1a.

125I-labeled botulinum type B neurotoxin was shown to bind specifically to recombinant rat synaptotagmins I and II. Binding required reconstitution of the recombinant proteins with gangliosides GT1b/GD1a. Scatchard plot analyses revealed a single class of binding site with dissociation constants of 0.23 and 2.3 nM for synaptotagmin II and synaptotagmin I, respectively, values very similar to those of the high- (0.4 nM) and low-affinity (4.1 nM) binding sites in synaptosomes. The high-affinity binding of neurotoxin to synaptosomes was specifically inhibited by a monoclonal antibody recognizing with the amino-terminal region of synaptotagmin II. These results suggest that this region of synaptotagmin II participates in the formation of the high-affinity toxin binding site by associating with specific gangliosides.

Amino Acid Sequence↗

Evaluation of 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose, a new fluorescent derivative of glucose, for viability assessment of yeast Candida albicans.

A new fluorescent derivative of D-glucose, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG), which had been previously developed for the analysis of glucose uptake activity by living cells, was investigated to evaluate its applicability for assaying the viability of yeast Candida albicans. Lineweaver-Burk plots showed to uptake of 2-NBDG to be competitively inhibited by D-glucose and not by L-glucose, which suggested the involvement of the glucose transporting system of C. albicans in the uptake of 2-NBDG. A good correlation was obtained between the yeast viability, determined by the plate-count method, and the 2-NBDG uptake activity of yeast cells (correlation constant: r = 0.97). This is expected to lead to the development of a new fluorescent probe for the determination of yeast cell viability.

4-Chloro-7-nitrobenzofurazan↗

Effect of IL-10 on collagen-induced arthritis in mice.

In the present study we investigated the effect of a potent anti-inflammatory cytokine, interleukin (IL)-10, on the development of collagen-induced arthritis (CIA) in mice. Each DBA1/J mouse was immunized with 200 micrograms of native collagen and followed by booster injections at 3 weeks. rmIL-10 was injected i.p. daily at a dose of 100 ng/mouse. Mice were divided into four groups according to the administration period of rmIL-10. As a result, a 48-day course of IL-10 treatment significantly suppressed the severity of arthritis. Among the 4 groups, the most pronounced suppression was observed in the group in which IL-10 was given from day 0 to 21. On the other hand, there were no significant differences in the serum IgG anti-type II collagen (CII) titers between the four groups. Moreover, the production of cytokines (IL-6 and tumor necrosis factor-alpha (TNF-alpha)) and other mediators (prostaglandin E2 (PGE2) and nitric oxide (NO)) by peritoneal macrophages seemed to show no clear correlation with the severity of arthritis in mice. These results raise the possibility that IL-10 might be a useful agent for suppressing the progression and the development of CIA in mice.

Analysis of Variance↗

Results of surgery for paralytic exotropia due to oculomotor palsy.

In 138 cases of paralytic exotropia due to oculomotor palsy, transposition of the superior oblique muscle and resection of the medial rectus muscle were carried out. Surgery was performed with or without recession of the lateral rectus muscle. The long-term prognosis for 4 years or more was observed in 35 cases. We found that the same results could be obtained by selecting transposition of the superior oblique muscle in cases of complete palsy and resection of the medical rectus muscle in cases of incomplete palsy. There was no benefit in combining resection of the medial rectus muscle when performing the transposition of the superior oblique muscle. Regardless of which method was used, a combination with recession of the lateral rectus muscle greatly improved the effectiveness of the procedure.

Adolescent↗

Intracellular fate of 2-NBDG, a fluorescent probe for glucose uptake activity, in Escherichia coli cells.

A fluorescent derivative of D-glucose, 2-NBDG, which was previously developed for the evaluation of glucose uptake activity by living cells, was used on Escherichia coli cells and its fate after incorporation in the cells was investigated. 2-NBDG was converted to another fluorescent derivative (2-NBDG metabolite) immediately after it was taken by E. coli cells. This 2-NBDG metabolite was then decomposed to non-fluorescent forms. 2-NBDG metabolite was decomposed into the original 2-NBDG by G6Pase with concurrent liberation of inorganic phosphate. Furthermore, FAB/MS analysis showed that its molecular weight was 420, the same value as that of 2-NBDG 6-phosphate. These indicate 2-NBDG metabolite should be 2-NBDG 6-phosphate. Based on these results, the feasibility of 2-NBDG as a fluorescent non-toxic probe for glucose uptake activity and its application to viability assessment of various living systems are discussed.

4-Chloro-7-nitrobenzofurazan↗

Suppression of superoxide anion production by interleukin-10 is accompanied by a downregulation of the genes for subunit proteins of NADPH oxidase.

Interleukin-10 (IL-10) inhibited the production of superoxide anion (02-) by both unactivated and interferon-gamma (IFN-gamma)-activated human monocytes. Simultaneous addition of IL-10 with IFN-gamma at the start of incubation was necessary for an optimal inhibitory effect. The degree of inhibition was substantially comparable to that of IL-4, and the combination of suboptimal concentrations of IL-10 and IL-4 produced an additive effect. A similar effect was also obtained when viral IL-10 (vIL-10) was used instead of IL-10. The inhibitory effect of IL-10 was accompanied by the reduced accumulation of transcripts for heavy chain subunit of cytochrome b558 (gp9l-phox) and 47-kD cytosolic factor (p47-phox), components of the O2--generating NADPH oxidase system. Reduction of the mRNAs was distinct within 24 hours. On the other hand, the induced O2- production by human monocytic leukemia cell lines (THP-1 and HL60) was not inhibited by IL-10. The amount of gp9l-phox and p47-phox mRNAs remained unchanged even in the presence of excess amount of IL-1O. Taken together, these results suggest that IL-10 inhibits 02- production by downregulation of the gp9l-phox and p47-phox genes in human monocytes.

Depression, Chemical↗