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Biomedical subjects

N Nakashima

Publications and source records attributed to N Nakashima.

At least 19 recordsLinked to original sources
PubMed1995

Fission yeast Rep2 is a putative transcriptional activator subunit for the cell cycle 'start' function of Res2-Cdc10.

In the yeast cell cycle 'start' requires sets of the Cdc10/ SWI family of transcriptional factors which activate the MCB cis elements contained in genes essential for S phase progression. Fission yeast possess two such overlapping systems, Res1-Cdc10 and Res2-Cdc10, both of which act to start the mitotic and meiotic cycles. We have recently isolated rep2+ as a multicopy suppressor of a temperature-sensitive cdc10 mutant which encodes a zinc finger protein. Here we show that the Rep2 zinc finger protein is an essential component of the active Res2-Cdc10 transcriptional regulator complex and likely to play a role in the control of cell cycle 'start'. Our data suggest that Rep2 is a transcriptional activator subunit which interacts with the MCB binding subunit complex formed by Res2 and Cdc10.

Amino Acid Sequence↗
PubMed1995

Nonpathogenic Nilaparvata lugens reovirus is transmitted to the brown planthopper through rice plant.

Nilaparvata lugens reovirus (NLRV) was found in a colony of the brown planthopper, N. lugens, an important plant virus vector. Unlike with usual phytopathogenic reoviruses, there are no visible symptoms on a rice plant which has been attacked by NLRV-infected planthoppers. Manner of transmission, host range, and multiplication of NLRV in rice plant were studied by enzyme-linked immunosorbent assay or polymerase chain reaction using reverse transcriptase. NLRV was transovumly transmitted to about 15% of nymphs. NLRV could further spread to planthoppers via rice plants through sucking by viruliferous insects. This horizontal transmission was apparently of primary importance for continuous NLRV infection to a colony of N. lugens. By corearing with viruliferous N. lugens on rice seedlings, Laodelphax striatellus acquired NLRV but Sogatella furcifera, Nephotettix cincticeps, and N. malayanus did not during the period studied. NLRV inoculated onto rice plant by viruliferous N. lugens failed to multiply, which accounts for the lack of symptoms on the plant even after an attack by viruliferous planthoppers. These biological properties and our previous data, which revealed a molecular similarity between NLRV and fijiviruses, suggest that NLRV is an ancestral virus of fijiviruses.

Animals↗
PubMed1995

Decreased interleukin-6 level in the cerebrospinal fluid of patients with Alzheimer-type dementia.

We examined IL-6 levels in the cerebrospinal fluid (CSF) of patients clinically diagnosed with Alzheimer-type dementia (ATD) and with vascular dementia (VD) and of age-matched normal subjects. The IL-6 levels in the CSF of ATD, but not VD patients, were significantly decreased. In the early onset ATD patients (disease onset < 65 years), IL-6 levels were reduced to 21% of the control level. The IL-6 levels in the CSF were not associated with the severity of the dementia or the duration of the disease since the identification of the first symptoms.

Acute-Phase Reaction↗
PubMed1995

Gonadoblastoma with dysgerminoma in one ovary and gonadoblastoma with dysgerminoma and yolk sac tumor in the contralateral ovary in a girl with 46XX karyotype.

A case of gonadoblastoma with dysgerminoma in the left ovary and gonadoblastoma with dysgerminoma and yolk sac tumor in the right of a 10-year-old girl is reported. Her karyotype was 46XX, normal female type. A case of a gonadoblastoma without a Y chromosome is very rare. Furthermore, the prognosis for gonadoblastoma accompanied by germ cell tumors other than dysgerminoma was very poor in the past, but the patient remains well 25 months after the first operation.

Child↗
PubMed1995

Effect of dehydroepiandrosterone on glucose uptake in cultured human fibroblasts.

Dehydroepiandrosterone (DHEA) and its sulfate derivative (DHEA-S) reportedly have antidiabetic and antiobesity effects. The effect of DHEA on glucose uptake in cultured human fibroblasts was examined. Incubation of cells with supraphysiologic concentrations of DHEA (10(-5) mol/L) for > or = 10 hours enhanced 2-deoxyglucose (2-DG) uptake significantly (P < .05). Supraphysiologic concentrations of insulin (10(-7) mol/L) increased the sensitivity of glucose uptake to DHEA. Conversely, the sensitivity of glucose uptake to insulin was increased by incubating cells with 10(-6) mol/L DHEA. Both the abundance of transcripts encoding glucose transporter-1 (Glut-1) and the maximal velocity (Vmax) of 2-DG transport were increased in cultured fibroblasts incubated with DHEA. Cultured fibroblasts expressed a specific binding factor with low affinity for [3H]DHEA (maximal number of binding sites, 18,496 sites per cell; Kd, 298 nmol/L). Other androgen hormones exerted a less-marked effect on glucose uptake; DHEA-S had no effect. These results suggested that DHEA increases Glut-1 mRNA through binding to a specific factor in cultured human fibroblasts and thereby stimulates glucose uptake in these cells.

Adult↗
PubMed1995

Phylogenetic position of yeast-like symbiotes of rice planthoppers based on partial 18S rDNA sequences.

The rice planthoppers, Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus, harbor intracellular yeast-like symbiotes (YLS) in the fat body. The YLS are obligated endosymbiotes and are transovarially inherited. Nucleotide sequences of the 18S rRNA genes from the YLS were analyzed by direct sequencing. The YLS of the three species of planthoppers were monophyletic and their taxonomic positions were in the class Pyrenomycetes in the subphylum Ascomycotina.

Animals↗
PubMed1995

[Hypoglycemic activity and mechanisms of extracts from mulberry leaves (folium mori) and cortex mori radicis in streptozotocin-induced diabetic mice].

Averaged blood glucose levels were 400 mg/dl in nonfasted mice, and 250 mg/dl in fasted mice in 4 weeks after injection with streptozotocin (STZ, 150 mg/kg, i.v.). These mice were used for experiments. Hypoglycemic effects of hot water extracts (W) from Folium Mori (Mulberry leaves, Morus alba L., China and Japan) or Cortex Mori Radicis (Morus alba L., China) were observed in fasted and nonfasted STZ-induced diabetic mice at a single dose of 200 mg/kg (i.p.). The W from Folium Mori exhibited most potent hypoglycemic effects. The most potent fractions of Folium Mori and Cortex Mori Radicis were ethanol-insoluble extracts (A2). These A2 fractions demonstrated a fall in blood glucose levels of 24.6 +/- 6.0% and 60.5 +/- 9.1% at nonfasted STZ-mice, and 81.4 +/- 7.9% and 77.3 +/- 5.8% at fasted STZ-mice, respectively. The increase in glucose uptake was a mechanism of hypoglycemic actions by W and A2 of Folium Mori.

Animals↗
PubMed1995

Salivary peptide P-C potentiates insulin release and inhibits glucagon release from isolated perfused pancreas of the diabetic GK rat.

We investigated the effects of the salivary peptide P-C (P-C), a saliva-derived peptide, on glucose (8.3 mM)- and arginine (10 mM)-induced insulin release and arginine (10 mM)-induced glucagon release using the perfused pancreas of spontaneously diabetic GK rats. Both its potentiating effect on insulin release and its inhibitory effect on glucagon release were concentration-dependent in diabetic GK rats. The ratio of insulin release obtained with P-C (194 nM) to that without P-C in GK rats was the same as ratio in normal Wistar rats. The ratio (0.40) of glucagon release obtained with P-C (194 nM) to that without P-C was smaller in diabetic GK rats than that (0.75) in normal Wistar rats. These results indicate that P-C inhibits arginine-induced glucagon release in diabetic GK rat pancreas more effectively than in normal Wistar rat pancreas.

Animals↗
PubMed1995

The essential amino acid domains in salivary peptide P-C that potentiate glucose-induced insulin release and inhibit arginine-induced glucagon release from perfused rat pancreas.

The amino acid domains in salivary peptide P-C (1-44 peptide fragments, P-C) that are essential to potentiate insulin release and inhibit glucagon release were investigated using isolated perfused rat pancreas. P-C significantly potentiated not only glucose (8.3 mM)-induced insulin release, but also arginine (10 mM)-induced insulin release. The essential domain responsible for potentiation of insulin release was the P-C-(23-29) fragment, 23KPQGPPP29, while that inhibiting glucagon release was the P-C-(12-18) fragment, 12HQQGPPP18. Since both domains share a common fragment, QGPP, these findings indicate that the functional amino acid sequences KP and HQ may potentiate insulin release and inhibit glucagon release, respectively.

Amino Acids↗
PubMed1995

Cardiac hypertrophy in obstructive sleep apnea syndrome.

Fifty-one middle-aged male patients with obstructive sleep apnea syndrome (OSAS) were evaluated using two-dimensional echocardiography, 24-h blood pressure measurements, polysomnography, and plasma norepinephrine (NE) measurements. Among these patients, left ventricular hypertrophy (LVH) (left ventricular posterior wall thickness [LVPWT] or interventricular septal thickness [IVST] > or = 12 mm) and right ventricular hypertrophy (RVH) (right ventricular wall thickness [RVT] > or = 5 mm) were present in 41.2% (21/51) and 11.8% (6/51). LVH was present in 50.0% of group 2 patients (apnea index > or = 20) and in 30.5% of group 1 patients (apnea index < 20). All patients with LVH had hypertension. RVH was present in 21.4% of group 2 patients and none of the group 1 patients. IVST, LVPWT, LV mass, LV mass/body surface area (BSA), and obesity index were significantly greater in group 2 than in group 1. Apnea index and the duration in which nocturnal oxygen saturation was decreased under 90% (duration of SaO2 < 90%), were significantly correlated with LV mass/BSA and 24-h mean blood pressure. Apnea index, number of apneas, duration of nocturnal oxygen saturation less than 90%, weight, and obesity index were significantly greater in patients with both LVH and RVH than in patients without LVH and RVH, or those with only LVH. Plasma NE after waking significantly increased compared with that before sleep (p < 0.05). The ratio of plasma NE levels after waking to those before sleep was significantly correlated with the duration of SaO2 < 90% (r = 0.83, p < 0.05), but not with apnea index. These results suggest that frequent episodes of oxygen desaturation and/or arousal responses caused by apnea may contribute to the complication of LVH and RVH in the long term, and apnea-induced cyclical increases in blood pressure and the resulting sustained elevation in blood pressure associated with the increase in afterload and sympathetic activity may play a role in the development of LVH.

Adult↗
PubMed1995

Bile duct-specific lectins, Dolichos biflorus agglutinin and peanut agglutinin, as probes in mouse hepatocarcinogenesis.

BACKGROUND: It is well established that alterations in the expression of cell surface glycoproteins occur during the course of tumorigenesis and can be detected immunohistochemically. However, no consistent markers of malignancy in mouse hepatocellular tumors have yet been identified. EXPERIMENTAL DESIGN: Lectin histochemistry, using three bile duct-specific lectins, Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA) and soybean agglutinin (SBA), and anti-epidermal keratin immunohistochemistry, was conducted on formalin-fixed, paraffin-embedded tissues of a spectrum of benign and malignant hepatocellular proliferative lesions of mice, including hepatocholangiocarcinomas. DBA- and PNA-binding glycoproteins in normal livers and in bile and liver tumors of mice were verified by SDS-PAGE and Western blot analysis. RESULTS: Normal bile duct cells stained strongly with DBA but minimally to moderately with PNA and SBA. DBA-positive tumor cells were present in 96% of hepatocholangiocarcinomas, 89% of hepatocellular carcinomas, and 35% of hepatocellular adenomas. In comparison, 43% of hepatocholangiocarcinomas, 37% of hepatocellular carcinomas, and 24% of hepatocellular adenomas exhibited PNA staining. SBA did not specifically stain tumor cells. Normal hepatocytes and those in altered foci were consistently negative for these three lectins. Keratin-positive staining was found only in normal bile ductular cells and ductal elements in 70% of hepatocholangiocarcinomas. Electrophoresis and Western blot analysis demonstrated that, in normal livers, DBA and PNA bound to the 13- to 16-kDa and 27- to 30-kDa glycoproteins believed to be of bile duct cell origin and commonly present in hepatocellular adenomas, hepatocellular carcinomas, and hepatocholangiocarcinomas, with strongest expression in the last. In addition, hepatocholangiocarcinomas had the same high molecular mass glycoprotein (> 200 kDa) labeled with DBA as detected in bile. CONCLUSIONS: Our results suggest that some malignant hepatocytes, especially in mouse hepatocholangiocarcinomas, have the potential of biliary differentiation. DBA is a sensitive marker for malignant hepatocytes in mice.

Adenoma↗
PubMed1995

[Detection of lupus anticoagulant using a modified diluted Russell's viper venom time test].

Lupus anticoagulants (LA) are considered to be a significant risk factor in patients with unexplained thrombosis and are often present in women who have recurrent miscarriages. According to Petri et al, LA detectable using a diluted Russell's Viper Venom time (dRVVT) test are more closely linked with thrombosis in patients with systemic lupus erythematosus than are anticardiolipin antibodies. We evaluated a new simplified dRVVT test, that is, a combination of LUPO-TESTII and LUCOR, and found that the ratio of LUPO-TESTII/LUCOR values is a good indicator for detection of LA. The cut-off point of the ratio based on receiver-operating characteristic (ROC) analysis was set at 1.07. The sensitivity and specificity were 92.3% and 96.8%, respectively. The ratio of LUPO-TESTII/LUCOR values of 24 (92.3%) of 26 LA-positive patients was significantly higher than those of warfarin-treated patients, patients with hereditary clotting-factor deficiency and patients positive for specific clotting-factor inhibitors (p < 0.01). It was shown that the result was not influenced by warfarin and/or heparin treatment and the presence of specific clotting-factor inhibitors. The ratio of LUPO-TESTII/LUCOR values is regarded as a more useful indicator for the detection of LA than the platelet neutralization procedure test.

Female↗
PubMed1994

[Maximum-intensity-projection CT angiography for evaluating head and neck tumors: usefulness of helical CT and auto bone masking method].

Angiographic images of 10 adult patients with head and neck tumors were obtained by helical computed tomography (CT) using maximum intensity projection (MIP). In all cases, the vasculature of the head and neck region was clearly visualized, and hypervascular lesions were directly demonstrated. In the head and neck, bone masking is a more important problem than in other regions. We developed an effective automatic bone masking method (ABM) using 2D/3D connectivity. Helical CT angiography with MIP and ABM provided accurate anatomic depiction, and was considered to be helpful in preoperative evaluation of head and neck tumors.

Adult↗
PubMed1994

Hac1: a novel yeast bZIP protein binding to the CRE motif is a multicopy suppressor for cdc10 mutant of Schizosaccharomyces pombe.

We cloned by phenotypic complementation a novel Saccharomyces cerevisiae's multicopy suppressor of the Schizosaccharomyces pombe cdc10-129 mutant which we call HAC1, an acronym of 'homologous to ATF/CREB 1'. It encodes a bZIP (basic-leucine zipper) protein of 230 amino acids with close homology to the mammalian ATF/CREB transcription factor and gel-retardation assays showed that it binds specifically to the CRE motif. HAC1 is not essential for viability. However, the hac1 disruptant becomes caffeine sensitive, which is suppressed by multicopy expression of the yeast PDE2 (Phosphodiesterase 2) gene. Although the mRNA level of HAC1 is almost constitutive throughout the cell cycle, it fluctuates during meiosis. The upstream region of the HAC1 gene contains a T4C site, a URS (upstream repression sequence) and a TR (T-rich) box-like sequence, which reside upstream of many meiotic genes. These results suggest that HAC1 may also be one of the meiotic genes.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1994

Differential diagnosis of ovarian tumors by transvaginal color-pulse Doppler sonography.

To investigate the clinical significance of transvaginal color-pulse Doppler sonography in ovarian tumors, 109 patients were examined at Nagoya University Hospital. Ultrasonographic patterns were classified and the levels of three circulating tumor markers, CA125, CA72-4, and CA19-9, were simultaneously evaluated. In differentiating benign and malignant ovarian tumors, transvaginal color-pulse Doppler and ultrasonographic pattern classification were superior to the tumor markers. Of 49 cases with benign pattern, 45 were benign (91.8%). Of 60 cases with malignant pattern, 24 (40%) were benign and 36 (60%) were malignant or borderline malignant. In this group color-pulse Doppler sonography was the most useful procedure, and sensitivity, specificity, and accuracy were 75.0, 79.2, and 76.7%, respectively. Menopausal status and site of the arterial wave form in the tumor were also important. Transvaginal color-pulse Doppler sonography was a reliable diagnostic method for differentiating ovarian tumors.

Adenocarcinoma↗
PubMed1994

Cloning of the Nilaparvata lugens reovirus genome: conserved terminal nucleotide sequences and nucleotide sequence of genome segment S10.

The segmented double-stranded RNA genome of Nilaparvata lugens reovirus (NLRV) was cloned, and the nucleotide sequence of genome segment S10 and terminal nucleotide sequences of the rest of the segments were determined. Genome segment S10 of NLRV consisted of 1430 nucleotides with a single open reading frame extending for 1293 nucleotides from nucleotide 46. It encoded a polypeptide of 431 amino acids with an M(r) of 49.4K, which was a non-structural protein. The plus-strand RNA of all genome segments had the same conserved trinucleotide 5' AGU- and hexanucleotide-GUUGUC 3' in the 5'- and 3'-terminal regions, respectively. These conserved terminal sequences resembled those found in the segments of the members of the genus Fijivirus.

Amino Acid Sequence↗
PubMed1994

Nucleotide sequence of Nilaparvata lugens reovirus genome segment S8 coding for the major outer capsid protein.

The complete nucleotide sequence of genome segment 8 (S8) of Nilaparvata lugens reovirus (NLRV) was determined. It consisted of 1802 nucleotides containing a long open reading frame (562 amino acids), which was expressed in Escherichia coli as a fusion protein. The expressed S8 product, a 62K protein, was detected by Western blotting using IgG directed against intact NLRV particles. This result indicates that S8 encodes the major outer capsid protein of NLRV. The protein exhibited 18.6% amino acid sequence identity with the predicted translation product of S10 of rice black-streaked dwarf virus.

Amino Acid Sequence↗