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Biomedical subjects

Y Kikuchi

Publications and source records attributed to Y Kikuchi.

At least 163 records · Page 9Linked to original sources

Yeast tom1 mutant exhibits pleiotropic defects in nuclear division, maintenance of nuclear structure and nucleocytoplasmic transport at high temperatures.

A tom1-1 mutant was isolated from Saccharomyces cerevisiae. At high temperatures, 60% of the cells were arrested as dumbbell forms with a single large nucleus containing duplicated DNA and a short spindle. Electron-microscopy showed electron-dense structures scattered within the nucleus. Indirect immunofluorescent microscopy revealed these structures to be fragmented nucleoli since the dotted structures were stained with anti-Nop1(fibrillarin) antibody in large regions of the nuclei. Fluorescent in situ hybridization analysis using oligo(dT) revealed nuclear accumulation of poly(A)+RNA. We cloned TOM1 which encodes a large protein (380kDa) with a hect (homologous to E6-AP C terminus)-domain at its C terminus. Deletions of either this hect-region or the entire gene made cellular growth temperature-sensitive. Site-directed mutagenesis of the conserved cysteine residue (tom1C3235A) in the hect-domain, supposed to be necessary for thioester-bond formation with ubiquitin, abolished the gene function. When a functional glutathione S-transferase (GST)-tagged hect protein was overproduced, it facilitated the protein conjugation with a myc-tagged ubiquitinRA, while this was not seen when GST-hectC3235A was overproduced. The protein conjugation with a hemagglutinin-tagged Smt3 was not affected by the overproduction of GST-hect. Taken together, we suggest that Tom1 is a ubiquitin ligase. As a multi-copy suppressor of tom1, we isolated STM3/NPI46/FPR3 which encodes a nucleolar nucleolin-like protein. We discuss possible functions of Tom1 with respect to the pleiotropic defects of nuclear division, maintenance of nuclear structure, and nucleocytoplasmic transport.

Amino Acid Sequence↗

Smt3, a SUMO-1 homolog, is conjugated to Cdc3, a component of septin rings at the mother-bud neck in budding yeast.

SMT3 of Saccharomyces cerevisiae is an essential gene encoding a ubiquitin-like protein similar to mammalian SUMO-1. When a tagged Smt3 or human SUMO-1 was expressed from GAL1 promoter, either gene rescued the lethality of the smt3 disruptant. By indirect-immunofluorescent microscopy, the HA-tagged Smt3 was detected mostly in nuclei and also at the mother-bud neck just like septin fibers. Indeed immunoprecipitation experiments revealed that Cdc3, one of septin components, was modified with Smt3. Furthermore, the protein level of the Cdc3-Smt3 conjugate was reduced and the septin rings disappeared in a ubc9-1 mutant at a restrictive temperature, where the Smt3 conjugation system should be defective. Thus, we conclude that Smt3 was conjugated to Cdc3 in septin rings localized at the mother-bud neck. Around the time of cytokinesis the Cdc3-Smt3 conjugate disappeared. We discuss the biological significance of this Smt3 conjugation to a septin component.

Cell Cycle Proteins↗

Suckling defect in mice lacking the soluble haemopoietin receptor NR6.

Cytokines control a variety of cellular responses including proliferation, differentiation, survival and functional activation, via binding to specific receptors expressed on the surface of target cells [1]. The cytokine receptors of the haemopoietin family are defined by the presence of a conserved 200 amino acid extracellular domain known as the haemopoietin domain [2]. We report here the isolation of NR6, a haemopoietin receptor that, like the p40 subunit of interleukin-12 (IL-12) [3] and the EBI3 gene induced by Epstein-Barr virus infection in lymphocytes [4], contains a typical haemopoietin domain but lacks transmembrane and cytoplasmic domains. Although in situ hybridisation revealed NR6 expression at multiple sites in the developing embryo, mice lacking NR6 did not display obvious abnormalities and were born in the expected numbers. Neonatal NR6(-/-) mice failed to suckle, however, and died within 24 hours of birth, suggesting that NR6 is necessary for the recognition or processing of pheromonal signals or for the mechanics of suckling itself. In addition, NR6(-/-) mice had reduced numbers of haemopoietic progenitor cells, suggesting a potential role in the regulation of primitive haemopoiesis.

Amino Acid Sequence↗

Mutational analysis of the feedback sites of lysine-sensitive aspartokinase of Escherichia coli.

In Escherichia coli, thrA, metLM, and lysC encode aspartokinase isozymes that show feedback inhibition by threonine, methionine, and lysine, respectively. In vitro chemical mutagenesis of the cloned lysC gene was used to identify residues and regions of the polypeptide essential for feedback inhibition by lysine. The isolated lysine-insensitive mutants were demonstrated to have missense mutations in amino acid residues 323-352, and at position 250 of aspartokinase III.

Amino Acid Sequence↗

Embryonal rhabdomyosarcoma of the uterine corpus in a 76-year-old patient.

BACKGROUND: Primary embryonal rhabdomyosarcoma of the uterine corpus is an extremely rare tumor. A case of rhabdomyosarcoma originating in the uterine myoma is presented with a review of the literature. CASE: A 76-year-old female presented with a half-year history of abdominal swelling and fever of unknown origin. A 15 x 15 x 17 cm myoma-like tumor was noted on the anterior wall of the uterine myometrium. The patient underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. The histology and immunohistochemistry aided in the final diagnosis of a pure embryonal rhabdomyosarcoma of the uterine corpus. This patient received three courses of CYVADIC chemotherapy consisting of cyclophosphamide, vincristine, doxorubicin, and dacarbazine after the surgery and is now alive with no evidence of disease 10 months from her surgery. CONCLUSION: This case is extremely rare with respect to the uterine corpus origin, especially the myoma nodule and the age of the patient.

Aged↗

Endosalpingiosis of nonmetastatic lymph nodes along the stomach in a patient with early gastric cancer: report of a case.

We report herein the case of a 32-year-old woman who underwent distal gastrectomy with D2 lymph node dissection for gastric cancer. Microscopic examination of the resected specimen revealed signet-ring cell carcinoma of the stomach with lymph node metastases, and endosalpingiosis in the normal lymph nodes. There was no evidence of malignancy in the peritoneal cavity. To our knowledge, no other case of endosalpingiosis in the lymph nodes along the stomach has ever been reported. The possible significance of endosalpingiosis is discussed following this case report.

Adult↗

MRI of the brain in the Kearns-Sayre syndrome: report of four cases and a review.

We report brain MRI findings in four patients with typical Kearns-Sayre syndrome (KSS) and correlate them with clinical manifestations. MRI was interpreted as normal in two patients; cerebral and cerebellar atrophy was seen in the other two. On T2-weighted spin-echo images, two patients had high-signal lesions bilaterally in subcortical white matter, thalamus and brain stem. In one patient, the white matter lesion extended into the deep cerebral white matter and the cerebellum was also affected. The other also had bilateral high-signal lesions in the globus pallidus. There was little correlation between neurological deficits and MRI findings. A review of the literature revealed that 10 of the 13 patients with typical KSS previously studied had bilateral subcortical white-matter lesions on T2-weighted images; at least 7 also had high-signal lesions in the brain stem, globus pallidus, thalamus or cerebellum. Although MRI may be normal or show atrophy, the characteristic finding in KSS is a combination of the high-signal foci in subcortical cerebral white matter and in the brain stem, globus pallidus or thalamus.

Adolescent↗

Effect of Korean red ginseng on psychological functions in patients with severe climacteric syndromes.

OBJECTIVE: To evaluate the degree of psychological dysfunction and levels of stress hormones in postmenopausal women with climacteric syndromes and effect of Korean red ginseng (RG) on them. METHODS: ACTH, cortisol and DHEA-S in peripheral blood from 12 postmenopausal women with climacteric syndromes or 8 postmenopausal women without any climacteric syndrome were measured before and 30 days after treatment with daily oral administration of 6 g RG. Blood samples were collected in the early morning on the bed-rest. In postmenopausal women with climacteric syndromes such as fatigue, insomnia and depression, psychological tests using the Cornell Medical Index (CMI) and the State-Trait Anxiety Inventory (STAI) were performed before and 30 days after treatment with RG. RESULTS: CMI score as well as anxiety (A)-state in STAI score in postmenopausal women with climacteric syndromes was significantly higher than that without climacteric syndrome, while DHEA-S levels in postmenopausal women with climacteric syndromes were about a half of those without climacteric syndrome. Consequently, cortisol/DHEA-S (C/D) ratio was significantly higher in postmenopausal women with climacteric syndromes than in those without climacteric syndrome. When postmenopausal women with climacteric syndromes were treated with daily oral administration of 6 g RG for 30 days, CMI and STAI A-state scores decreased within normal range. Although the decreased DHEA-S levels were not restored to the levels in postmenopausal women without climacteric syndrome, the C/D ratio decreased significantly after treatment with RG. CONCLUSIONS: Improvement of CMI and STAI scores in postmenopausal women suffering climacteric syndromes, particularly fatigue, insomnia and depression, by RG seemed to be brought about in part by effects of RG on stress-related hormones as shown by a decrease in C/D ratio.

Adrenocorticotropic Hormone↗

Acute relapsing encephalopathy mimicking acute necrotizing encephalopathy in a 4-year-old boy.

A 4-year-old boy showed two episodes of encephalitis/encephalopathy involving disturbed consciousness, convulsion, and paresis associated with the elevated levels of protein and myelin basic protein of the cerebrospinal fluid. MRI studies of the brain revealed symmetrical lesions in the brain stem and thalami at the first episode, and additional lesions were found in the cerebellum involving both the gray and white matter in the second episode. The intensities of MRI lesions were low in T I and high in T2. These episodes were followed by an elevation of the anti-viral antibody titers, for influenza A virus during the first episode and for adenovirus during the second. In the second episode, intravenous methylprednisolone therapy resulted in rapid improvement of his neurological signs.

Brain↗

Compartmentalized expression of zebrafish ten-m3 and ten-m4, homologues of the Drosophila ten(m)/odd Oz gene, in the central nervous system.

Zebrafish ten-m3 and ten-m4 encode proteins highly similar to the product of Drosophila pair-rule gene ten(m)/odd Oz (odz). Their products contain eight epidermal growth factor (EGF)-like repeats that resemble mostly those of the extracellular matrix molecule tenascin. During segmentation period, ten-m3 is expressed in the somites, notochord, pharyngeal arches, and the brain, while expression of ten-m4 is mainly restricted to the brain. In the developing brain, ten-m3 and ten-m4 expression delineates several compartments. Interestingly, ten-m3 and ten-m4 show expression patterns complementary to each other in the developing forebrain and midbrain along both rostrocaudal and dorsoventral axes, depending on developmental stages and locations.

Amino Acid Sequence↗

Bcl-2 as a predictor of chemosensitivity and prognosis in primary epithelial ovarian cancer.

This retrospective study of ovarian cancer aimed to elucidate whether expression of apoptosis-related proteins, bcl-2, p53 or MDM-2, is associated with resistance to chemotherapy, especially cisplatin (CDDP) based chemotherapy. Expression of bcl-2, p53 and MDM-2 was assessed by immunohistochemical staining of tumour tissues collected at initial surgery prior to treatment with CDDP-based chemotherapy. Among 66 patients with advanced ovarian cancer with measurable tumour following surgery and evaluable for response to chemotherapy, 42, 45 and 56% were positive for bcl-2, p53 and MDM-2, respectively. Significantly fewer tumours of patients who had a complete response to chemotherapy (CR) showed positivity for bcl-2 (2/20) than for p53 (6/20) and MDM-2 (8/20, P < 0.001). There was an inverse correlation between bcl-2 staining and initial response to chemotherapy, especially in serous and endometrial adenocarcinomas. In patients with stage III-IV, serous or endometrioid adenocarcinomas, significantly poorer survival was seen for those with bcl-2 positive tumours than those with negative bcl-2 staining (P = 0.0064). p53 and MDM-2 were not correlated with initial response to chemotherapy. Multivariate analysis revealed that bcl-2, residual tumour size and histology were significant independent prognostic factors. These results suggest that bcl-2 can be a possible predictor of response to chemotherapy and prognosis in patients with advanced ovarian carcinoma.

Antineoplastic Agents↗

ICH-harmonised guidances on genotoxicity testing of pharmaceuticals: evolution, reasoning and impact.

The International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) has convened an expert working group which consisted of the authors of this paper and their respective committees, consulting groups and task forces. Two ICH guidances regarding genotoxicity testing have been issued: S2A, 'Guidance on Specific Aspects of Regulatory Genotoxicity Tests' and S2B, 'Genotoxicity: A Standard Battery for Genotoxicity Testing of Pharmaceuticals.' Together, these guidance documents now form the regulatory backbone for genotoxicity testing and assessment of pharmaceuticals in the European Union, Japan, and the USA. These guidances do not constitute a revolutionary new approach to genotoxicity testing and assessment, instead they are an evolution from preexisting regional guidelines, guidances and technical approaches. Both guidances describe a number of specific criteria as well as a general test philosophy in genotoxicity testing. Although these guidances were previously released within the participating regions in their respective regulatory communiqués, to ensure their wider distribution and better understanding, the texts of the guidances are reproduced here in their entirety (see Appendix A) and the background for the recommendations are described. The establishment of a standard battery for genotoxicity testing of pharmaceuticals was one of the most important issues of the harmonisation effort. This battery currently consists of: (i) a test for gene mutation in bacteria, (ii) an in vitro test with cytogenetic evaluation of chromosomal damage with mammalian cells or an in vitro mouse lymphoma tk assay, (iii) an in vivo test for chromosomal damage using rodent hematopoietic cells. A major change in testing philosophy is the acceptance of the interchangeability of testing for chromosomal aberrations in mammalian cells and the mouse lymphoma tk assay. This agreement was reached on the basis of the extensive review of databases and newly generated experimental data which are in part described in this publication. The authors are fully aware of the fact that some of the recommendations given in these ICH guidances are transient in nature and that the dynamic qualities and ongoing evolution of genetic toxicology makes necessary a continuous maintenance process that would serve to update the guidance as necessary.

Animals↗

Mumefural, citric acid derivative improving blood fluidity from fruit-juice concentrate of Japanese apricot (Prunus mume Sieb. et Zucc).

The effects of food components on blood fluidity were studied by in vitro assay using a dedicated microchannel instrument for model capillaries. We found that the fruit-juice concentrate of the Japanese apricot (Prunus mume Sieb. et Zucc), a traditional Japanese food, markedly improved the fluidity of human blood. Using HPLC, we isolated the active compounds and characterized them using UV, MS, IR, and NMR. They included a novel compound, 1-[5-(2-formylfuryl)methyl] dihydrogen 2-hydroxypropane-1,2, 3-tricarboxylate (mumefural), and a related compound, 5-hydroxymethyl-2-furfural (HMF). Mumefural markedly improved blood fluidity in all subjects, while HMF worked differently in different individuals. The flow rate of blood spiked with mumefural or HMF was compared to that of the two predominant organic acids in the fruit. Citric acid, malic acid, and furfuryl alcohol also improved fluidity in all subjects. The activity of P. mume is derived from not only artifacts produced during thermal processing, such as mumefural, but also from endogenous organic acids.

Beverages↗

Accelerated solvent extraction of paclitaxel and related compounds from the bark of taxus cuspidata

Accelerated solvent extraction (ASE) of paclitaxel and related compounds from Taxus cuspidata (Japanese yew) bark has been investigated under various conditions. In ASE, pressure is applied to the sample extraction cell to maintain the heated solvent in a liquid state during the extraction. This method is able to shorten the extraction time and to increase the recovery of target compounds. In this study, ASE of paclitaxel, baccatin III, and 10-deacetylbaccatin III produced amounts of these compounds that were higher than those from ordinary solvent extraction at room temperature. The conditions providing the highest recovery of paclitaxel were as follows: solvent, MeOH-H2O (90:10); temperature, 150 degrees C; and pressure, 10.13 MPa (0.128% w/w recovery based on oven-dried sample powder). ASE does not require chlorinated solvents and can reduce solvent consumption because of its strong dissolving power. Moreover, with water alone, the recovery of paclitaxel and related compounds using ASE is much higher than with other extraction methods.

Journal Article↗

Skin eruption as the presenting sign of Hunter syndrome IIB.

We present a case of Hunter syndrome diagnosed because of skin eruption. A 4-year-old Japanese boy presented with a 3-4-months history of papular lesions on the back and extremities. His growth and development were almost normal. His face was not of coarse appearance. He had multiple, whitish to skin-coloured, papules and nodules symmetrically distributed on the scapular regions and the extensor aspects of the upper arms and thighs. There was no family history of similar symptoms. Skin biopsy showed the deposition of a considerable amount of mucin in the dermis. Although physical examinations failed to detect any other signs of Hunter syndrome, X-rays showed the characteristic features of mucopolysaccharidosis: deformities of the vertebral bone, ribs, and pelvis. Mucopolysaccharide analysis of the urine revealed a marked increase in dermatan sulphate and heparan sulphate. The activity of iduronate sulphatase in the lymphocytes was deficient, which was diagnostic for Hunter syndrome. We emphasize that the skin eruption can be the earliest sign of Hunter syndrome, particularly in the mild form presenting with normal development and growth.

Child, Preschool↗

Volume-pressure properties of the upper airway in normal subjects and patients with obstructive sleep apnoea.

The aim of this study was to examine the volume-pressure (V-P) characteristics of isolated upper airways in normal subjects and patients with obstructive sleep apnoea (OSA) and to ascertain whether an increase in upper airway muscle activity affects these characteristics. We studied upper airway pressure changes during volume changes by inflation and deflation of air volumes of 5, 10, 15 and 20 mL without and with submental electrical stimulation, during voluntary closing of the glottis, in seven normal subjects and 13 OSA patients. Volume-pressure properties of the upper airway were assessed by elastance (Euaw) which was obtained from the slope of the regression line of the V-P relationships. Euaw in OSA patients was 0.52 +/- 0.08 cmH2O/mL, which was greater than in normal subjects (0.26 +/- 0.06 cmH2O/mL). Submental stimulation increased Euaw in both OSA patients and normal subjects (0.70 +/- 0.11 cmH2O/mL and 0.41 +/- 0.11 cmH2O/mL, respectively). These results suggest that upper airways of OSA patients during wakefulness are less collapsible than those of normal subjects, and that, in both groups, submental stimulation may stiffen the upper airway.

Adult↗

Caspase activation accompanying cytochrome c release from mitochondria is possibly involved in nitric oxide-induced neuronal apoptosis in SH-SY5Y cells.

It is well known that caspases are produced as proforms, which are proteolytically cleaved and activated during apoptosis or programmed cell death. We report here that caspases are activated during apoptosis by treatment with NOC18, a nitric oxide (NO) donor. Our present experiments have examined the way in which NO induces neuronal cell death, using a new type of NO donor that spontaneously releases only NO without enzymatic metabolism. NOC18 induced apoptosis in human neuroblastoma SH-SY5Y cells in a concentration- and time-dependent manner as estimated by DNA fragmentation assay, FACScan analysis, and nuclear morphology. Oxyhemoglobin, an NO trapper, suppressed NOC18-triggered DNA fragmentation, indicating that NO from NOC18 is a real activator in this study. Upon the induction of apoptosis, an increase in caspase-3-like protease activity, but not caspase-1, was observed. Procaspase-2 protein, an inactive form of caspase-2, decreased dramatically. In addition, NOC18 also resulted in poly (ADP-ribose) polymerase (PARP) cleavage, yielding an 85-kDa fragment typical of caspase activity. Oxyhemoglobin blocked the decrease of procaspase-2 and the cleavage of PARP by NOC18 in a concentration-dependent manner. Moreover, NO elicited the release of cytochrome c into the cytosol during apoptosis. These results suggest that both stimulation of caspase activity and cytochrome c release are partly involved in NO-induced neuronal apoptosis.

Apoptosis↗