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T Noda

Publications and source records attributed to T Noda.

At least 181 records · Page 10Linked to original sources
PubMed1997

A novel genetic system to isolate a dominant negative effector on DNA-binding activity of Oct-2.

Recent studies have revealed that interactions between transcription factors play an important role in regulation of gene expression in eukaryotic cells. To isolate cDNA clones that dominantly inhibit the DNA-binding activity of Oct-2, chosen as a representative factor, we have developed a novel screening system. This employs an Escherichia coli tester strain carrying a modified lac operon as a reporter gene, with the lac operator sequence replaced by an octamer sequence. Oct-2 expressed in this tester strain represses the expression of the reporter gene and changes the phenotype of the cell from Lac+to Lac-. Introduction of a cDNA expression library prepared from a human T-cell line into the Oct-2-harboring tester strain allowed selection of three Lac+clones out of 1 x 10(5) transformants. One of them, hT86, encoding a putative zinc finger protein was found to derepress beta-galactosidase activity in the Oct-2-harboring tester strain at the transcriptional level. In gel mobility shift assays, hT86 attenuated the intensity of the retarded band composed of the octamer probe and Oct-2, suggesting a dominant negative effect on the DNA-binding activity of Oct-2. The strategy described here provides a new approach for studying protein-protein interactions that govern the complex regulation of gene expression.

Amino Acid Sequence↗
PubMed1997

Genetic and physical delineation of the region of the mouse deafness mutation shaker-2.

A total of 951 backcross progeny have been obtained from a backcross segregating for the mouse deafness mutation, shaker-2(sh-2). Linkage analysis provides a detailed genetic map in the vicinity of sh-2 which comprises 40 backcross mice identified as recombinant within a 4 cM region. This allows construction of a contig consisting of 21 BAC clones across an approximately 700-kb region of sh-2. This covers the entire nonrecombinant region of sh-2 and is therefore useful to facilitate the identification of genes in the sh-2 region.

Animals↗
PubMed1997

Creation of libraries with long ORFs by polymerization of a microgene.

We describe a novel method for constructing pools of DNA sequences that encode large proteins with molecular diversity. Sets of primer pairs that form 8 to 10 complementary base pairs in the 3' region and have double mismatch pairs at their 3'-OH ends were designed so that primer dimers recreated short stretches of DNA (microgenes) devoid of termination codons. Cycles of denaturation and elongation reactions with a pair of primers, four dNTPs, and 3'-5' exo+ thermostable DNA polymerase gave head-to-tail polymers of the primer dimer unit (microgene) whose sizes exceeded 12 kb. No template was required in this reaction, but mismatched nucleotides at 3'-OH ends of the primers were critical for efficient polymerization. At end-joining junctions of a microgene, nucleotide insertions and deletions randomly occurred, resulting in combinatorial libraries of three reading frames from a single microgene. Further molecular diversity could be incorporated by using a mixture of primers. The resultant polymers have long ORFs whose products have a repetitious nature that could facilitate the formation of higher structures of translated products. Thus, microgene polymers may be used as a source of libraries for in vitro protein evolution experiments. Ligation of a microgene is apparently related to the nonhomologous recombination of double-strand breaks in DNA that has been shown to be catalyzed by DNA polymerases. We named this polymerization reaction the "microgene polymerization reaction."

Amino Acid Sequence↗
PubMed1997

Unrestrained nociceptive response and disregulation of hearing ability in mice lacking the nociceptin/orphaninFQ receptor.

In the G-protein-coupled receptor superfamily, the opioid receptor subfamily is constituted of the three distinct opioid receptors (namely delta-, mu- and kappa-subtypes) and the receptor for nociceptin (also designated orphaninFQ). The members of the opioid receptor subfamily were known to mediate a variety of cellular inhibitory effects. The three opioid receptors are known to play central roles in mediating analgesia and many other physiological activities; however, the nociceptin receptor was identified recently and less is known about its physiological roles. Here we report the generation and characterization of mice lacking the nociceptin receptor. The knockout mice showed no significant differences in nociceptive threshold and locomotor activity compared with control mice, but they lost nociceptin-induced behavioral responses. These results indicate that the nociceptin system is not essential for regulation of nociception or locomotor activity. On the other hand, we found insufficient recovery of hearing ability from the adaptation to sound exposure in the mutant mice. Thus, the nociceptin system appears to participate in the regulation of the auditory system.

Animals↗
PubMed1997

A role for macrophage scavenger receptors in atherosclerosis and susceptibility to infection.

Macrophage type-I and type-II class-A scavenger receptors (MSR-A) are implicated in the pathological deposition of cholesterol during atherogenesis as a result of receptor-mediated uptake of modified low-density lipoproteins (mLDL). MSR-A can bind an extraordinarily wide range of ligands, including bacterial pathogens, and also mediates cation-independent macrophage adhesion in vitro. Here we show that targeted disruption of the MSR-A gene in mice results in a reduction in the size of atherosclerotic lesions in an animal deficient in apolipoprotein E. Macrophages from MSR-A-deficient mice show a marked decrease in mLDL uptake in vitro, whereas mLDL clearance from plasma occurs at a normal rate, indicating that there may be alternative mechanisms for removing mLDL from the circulation. In addition, MSR-A-knockout mice show an increased susceptibility to infection with Listeria monocytogenes or herpes simplex virus type-1, indicating that MSR-A may play a part in host defence against pathogens.

Animals↗
PubMed1997

Standard splenic volume in children and young adults measured from CT images.

The number of children and adolescents with hypersplenism is increasing as the number of long-term survivors undergoing successful Kasai operation for biliary atresia increases. The aim of this study was to determine the standard splenic volume in normal children and adolescents. We measured the splenic volumes with computed tomography (CT) images obtained from 49 Japanese children, adolescents, and young adults, ranging from 9 days to 25 years of age, and from 3.0 kg to 89.0 kg of body weight. The best correlation was observed between splenic volume (SV: cm3) and body weight (BW: kg) with a power curve regression; SV = 6.516 BW0.797, r = 0.924. The splenic volume and age (AG: years) also correlated well on a power curve; SV = 41.879 AG0.411, r = 0.897. The ratio of the splenic volume to the body weight (SV/BW: cm3/kg) decreased with age; from 4.5 cm3/kg at 1 month to 2.4 cm3/kg at 25 years of age, according to an exponential curve; SV/BW = 4.473e-0.026AG, r = 0.593. The above formulas are thus considered to be clinically useful, especially in the assessment of splenic size in children with hypersplenism both before and after partial splenic embolization.

Adolescent↗
PubMed1997

Liver volume in children measured by computed tomography.

Liver volume was measured by computed tomography in 54 children and young adults with no history of liver disease. Their ages ranged from 10 days to 22 years. The volume was calculated as follows: (1) the edges of the liver were traced on each scan image and the area was calculated by computer; (2) the areas were summed and multiplied by the scan interval in centimeters. The mean liver volume (+/-SD) was 178.2 +/- 81.9 cm3 in infants (less than 12 months old) and 1114.3 +/- 192.9 cm3 in adolescents (more than 16 years old). The mean liver volume in relation to body weight (+/-SD) was 34.1 +/- 5.5 cm3/kg in infants and 20.2 +/- 3.1 cm3/kg in adolescents. In general, liver volume increases rapidly in infants, gradually in schoolchildren, and not at all in adolescents. Volumetry might be clinically useful for evaluating the liver function in children and determining the graft size in liver transplantation.

Adolescent↗
PubMed1997

A simple and reliable quick-freezing/freeze-fracturing procedure.

We describe a simple method for the quick-freezing/freeze-fracturing of cells in tissues or culture monolayers. Tissue slices or cultured cells were covered with thin copper foil (10-micron-thick), and frozen by smashing them against a liquid helium-cooled copper block. Freeze-fracturing was accomplished by mechanically separating the copper foil from the frozen specimen. The fracture faces were replicated by platinum and carbon. Replicas were processed for conventional electron microscopic observation or cytochemical labeling. This method allows the ultrastructural and cytochemical examination of large areas of fractured membrane without chemical fixation.

Animals↗
PubMed1997

Plasma Fas ligand, an inducer of apoptosis, and plasma soluble Fas, an inhibitor of apoptosis, in patients with chronic congestive heart failure.

OBJECTIVES: This study sought to examine plasma levels of soluble Fas/APO-1 receptor (sFas), an inhibitor of apoptosis, and soluble Fas ligand (sFas-L), an inducer of apoptosis, and their relation to each other and to other clinical variables, such as New York Heart Association functional class, tumor necrosis factor (TNF) and interleukin-6 (IL-6) in congestive heart failure (CHF). BACKGROUND: It has been recently reported that apoptotic cell death occurs in myocytes of dogs with CHF. Hypoxia is frequently seen in advanced CHF and can stimulate Fas/APO-1 receptors (Fas) to induce apoptosis in cultured myocytes. Fas and Fas ligand (Fas-L) are cell-surface proteins and representative apoptosis-signaling molecules. Fas on the cell membrane induces apoptosis when it binds Fas-L or sFas-L. However, plasma sFas, a molecule lacking the transmembrane domain of Fas, blocks apoptosis by inhibiting binding between Fas and Fas-L or sFas-L on the cell membrane. At present, it is unknown whether plasma sFas-L and plasma sFas increase in the presence of cardiac disease. METHODS: The study included 70 patients (mean [+/-SEM] age 65 +/- 2 years, range 21 to 93) with chronic CHF (coronary artery disease in 28, dilated cardiomyopathy in 27, valvular heart disease in 15) and 62 age- and gender-matched normal control subjects. Plasma levels of sFas, sFas-L, TNF-alpha and IL-6 were measured by enzyme-linked immunosorbent assays using monoclonal anti-human antibodies. RESULTS: There was no significant difference in sFas-L levels between normal subjects and patients in functional classes I to IV; however, sFas increased with severity of functional classification, independent of the underlying disease. sFas levels were significantly higher even in patients in functional class II than in normal subjects and those in functional class I, and were highest in patients in functional class IV (normal subjects; 2.2 +/- 0.1 ng/ml; functional class I: 2.2 +/- 0.2 ng/ml; functional class II: 3.1 +/- 0.2 ng/ml; functional class III: 3.9 +/- 0.3 ng/ml; functional class IV: 5.1 +/- 0.6 ng/ml). Plasma sFas levels were significantly higher in patients with elevated pulmonary artery wedge pressure and a decresed cardiac index than in those with values in the normal range. In patients in functional class IV, there was no significant difference in plasma sFas levels between the survivors and non-survivors during 6-month follow-up. However, plasma levels of sFas tended to decrease in nine patients with clinical improvement (baseline sFas: 5.2 +/- 0.8 ng/ml; 6-month sFas: 4.3 +/- 0.5 ng/ml, p = 0.07) but were similar in patients with no change in functional class. TNF-alpha and IL-6 were increased significantly only in patients in functional class IV, as previously reported, but were not related to sFas. CONCLUSIONS: We found elevated levels of plasma sFas and no increase in plasma sFas-L in human CHF. The increase in sFas may play an important role in the pathophysiologic mechanisms of CHF.

Aged↗
PubMed1997

Differences in nitric oxide synthase activity in a macrophage-like cell line, RAW264.7 cells, treated with lipopolysaccharide (LPS) in the presence or absence of interferon-gamma (IFN-gamma): possible heterogeneity of iNOS activity.

Nitric oxide synthase (NOS) activities were compared in a macrophage-like cell line, RAW 264.7 cells, treated with bacterial lipopolysaccharide (LPS) alone or with LPS and interferon-gamma (IFN-gamma). An about 5-6-fold higher amount of NO2-originating from the nitric oxide radical (.NO) was produced in the culture supernatant of macrophages treated with LPS + IFN-gamma than with LPS alone, depending on both the time of incubation and the dose of LPS. However, the difference in the amounts of iNOS protein in these macrophage extracts was much greater than that in the amount of released NO2-. To estimate the NOS activity after induction of NOS at 37 degrees C for 8 h, we examined both intact cells and cell extracts. The cells were washed and re-incubated in Hank's balanced salt solution (HBSS) containing 1 mM L-arginine and 100 microM carboxy-PTIO, which enabled us to detect trace amounts of .NO by means of rapid reaction of carboxy PTIO with .NO to form .NO2, which was finally converted to NO2-. The results showed an about 7-fold difference between the macrophages pretreated with LPS alone and those with LPS + IFN-gamma. Using the extracts, the NOS activity was assayed with L-[U-14C]arginine as a substrate for NOS in vitro, and the results again revealed an about 7-fold difference between the two types of cell extracts. A kinetic study of the NOS activity by means of in vitro assay suggested that there was little difference in Km value for L-arginine between these two iNOSs. However, it revealed two apparent Kms for beta-NADPH, a co-factor of NOS; one was about 0.4 microM, which was common to these two iNOSs, and the other was about 1.5 and 25 microM for LPS-induced NOS and LPS + IFN-gamma-induced NOS, respectively. The cellular concentration of beta-NADPH was around 14 microM in both LPS- and LPS + IFN-gamma-treated macrophages. These results suggest that there is some heterogeneity of iNOSs induced in macrophages with LPS alone and with LPS + IFN-gamma, and the heterogeneity seems to be due at least in part to the requirement for beta-NADPH.

Animals↗
PubMed1997

Helicobacter pylori extracts exhibit nicotinamide adenine dinucleotide-derived adenylation but not mono(adenosine 5'-diphosphate-ribosyl)ation of DNA ligase.

The issue of toxins produced by Helicobacter pylori (H. pylori) urgently requires clarification given that the bacterium causes gastric epithelial cell damage which may lead to precancerous and cancerous changes. During an investigation of the possibility of mono(adenosine 5'-diphosphate (ADP)-ribosyl)ation by H. pylori products, as observed for other bacterial toxins, we found that radioactivity of [adenylate-32P]nicotinamide adenine dinucleotide (NAD) is incorporated into an H. pylori protein of 80 kDa after incubation with crude bacterial extract. In contrast, [carbonyl-14C]NAD did not show any radioactivity incorporation. Unexpectedly, treatment of the modified protein with 0.1 N HCl, but not 0.1 N NaOH, released the AMP moiety. Such chemical properties are characteristic of bacterial DNA ligase-AMP complexes. We found that an antibody raised against Escherichia coli DNA ligase [EC 6.5.1.2] immunoprecipitated the modified 80 kDa protein. Our results indicate that incorporation of radioactivity derived from NAD into the 80 kDa protein was due to adenylation, but not mono(ADP-ribosyl)ation, of the DNA ligase of H. pylori.

Adenosine Diphosphate Ribose↗
PubMed1997

Experimental study of ascending Candida albicans pyelonephritis focusing on the hyphal form and oxidant injury.

To investigate the pathogenicity of the hyphal form of Candida in pyelonephritis a Candida albicans strain, assuming only the yeast form but not the hyphal form when induced by ultraviolet mutagenesis, and a revertant strain from this mutant strain showing bimorphism were compared in a rat experimental model with regard to the incidence of ascending Candida pyelonephritis and the grade of inflammation. To increase the frequency of pyelonephritis unilateral incomplete ureteral stenosis was created. The revertant strain assuming the hyphal form showed a significantly (p < 0.01) higher frequency of pyelonephritis as compared with the mutant strain not assuming this form, and the grade of inflammation was also higher in the revertant strain group. Also, higher renal tissue and serum levels of both lipid peroxide and superoxide dismutase, which are related to marked renal oxidant injury, tended to be correlated with the degree of neutrophil infiltration in the acute phase. These findings suggest that the hyphal form plays an important role in the development of C. albicans pyelonephritis and also that the oxygen radicals from neutrophils appearing at the sites of inflammation play a major part in the further extension of inflammatory lesions.

Animals↗
PubMed1997

Mutational analysis of Csc1/Vps4p: involvement of endosome in regulation of autophagy in yeast.

In the yeast Saccharomyces cerevisiae, autophagy, a bulk protein degradation in the vacuole, is induced in response to nutrient starvation. In a screen for mutations that result in induction of autophagy even in the presence of nutrients, we have isolated four mutants representing two csc complementation groups. These mutants induce autophagy of which activity is represented by activation of truncated alkaline phosphatase that is designed to be expressed in the cytosol. CSC1 was cloned by complementation of loss of viability phenotype of csc1-1 mutant and shown to be identical to END13/VPS4/GRD13. Though csc1-1 mutation is recessive, cells of delta csc1 do not induce autophagy in rich media, suggesting that csc1-1 allele is not a complete loss-of-function. Csc1p is a member of novel ATPase family named AAA protein including Sec18p/NSF, Cdc48p/p97, and Pas8p. Mutation site in csc1-1 is found in the SRH region that is highly conserved among AAA proteins. Cells of csc1-1 show sorting defect of CPY and the appearance of the class E compartment. These mutant phenotypes suggest the role of the protein that is involved in the traffic among the Golgi, endosome, and the vacuole in autophagy.

Adenosine Triphosphatases↗
PubMed1997

[New medicinal action of native hormone].

Estrogen is involved in the growth and development of female organs such as uterus and mammary gland. On the other hand, from clinical point of view, it is recently suggested that estrogen is effective to protect postmenopausal women from osteoporosis, coronary heart disease and Alzheimer disease. In order to study the molecular mechanism of estrogen action, we have identified an estrogen responsive gene, efp (estrogen-responsive finger protein), which might mediate estrogen action in various target organs at diverse stages and targeted mutagenesis of efp gene could help clarify physiologic actions of estrogen.

Alzheimer Disease↗
PubMed1997

Changes of hepatic volume after successful Kasai operation.

The number of long term survivors who have undergone Kasai operation for biliary atresia is increasing, but some have a hepatic dysfunction likely to require liver transplantation in the near future. Hepatic volume possibly reflects whole liver function, and our objective was to assess the changes of hepatic volume after Kasai operation. Ten patients were studied. Ages ranged from 3 to 27 years. They underwent Kasai operation at ages ranging from 50 to 80 days. Liver areas (cm2) on CT images were measured with an image processing and analysis program (NIH Image 1.57). Hepatic volume (cm3) was calculated by summing up the areas of each image and multiplying by slice thickness (cm). After Kasai operation, the size of the liver increased to 1.7-1.9 times the standard volume, and then reduced to normal size around 5 years of age. In the teens, hepatic volume decreased below the standard volume. Segmental hypertrophy accompanying atrophy of other hepatic segments was observed in 9 out of 10 patients; right lobe hypertrophy: 6, medial segment: 2, and lateral segment: 1. Therefore, progressive hepatic atrophy begins in the teens, but is compensated for by segmental hypertrophy.

Adolescent↗
PubMed1997

[A case of multiple endocrine neoplasia type I with primary hyperparathyroidism, prolactin secreting pituitary microadenoma and gastrin secreting duodenal carcinoid].

A case of MEN type I in a 64-year-old man is reported. He had undergone partial duodenectomy because of gastric ulcer and multiple duodenal polyps (gastrin secreting carcinoid). Blood examination revealed hypercalcemia, hyperPTHemia, and hyperprolactinemia. Neck US and CT showed enlargement of 4 parathyroid glands. Brain MRI revealed the microadenoma in left pituitary gland. Total parathyroidectomy with auto-transplantation in the left forearm were performed. Histological examination showed the hyperplasia of the parathyroid. Three and a half year after parathyroidectomy, there was no evidence of recurrence of gastrin secreting tumor and hyperparathyroidism, and enlargement of pituitary microadenoma. This is the first MEN type I case in Japan which have detected 3 endocrine tumors clinically with gastrin secreting duodenal carcinoid.

Adenoma↗