Search PubMed⌕ Search

Biomedical subjects

N Kudo

Publications and source records attributed to N Kudo.

At least 19 recordsLinked to original sources
PubMed2003

Characterization of monoclonal antibodies against Gnathostoma nipponicum.

Monoclonal antibodies (mAbs) were produced against the proteins of advanced third-stage larvae (AdL3) of Gnathostoma nipponicum. Six mAbs (Gn2C3, Gn2H3, Gn4C3, Gn4E9, GnSH1, and Gn10B7) were obtained as determined by enzyme-linked immunosorbent assay (ELISA). Gn4E9 and GnSH1 seemed to be genus-specific, as they did not cross-react with Anisakis sp., Dirofilaria immitis, Gongylonema pulchrum, Toxocara canis, Trichinella sp., Trichuris vulpis, Metagonimus sp., or Spirometra erinaceieuropaei by ELISA. Immunohistochemistry showed that Gn2C3, Gn4E9, and Gn5H1 reacted strongly with the central esophagus; Gn2H3 reacted with cuticle,muscle, intestine, and the cervical sac; and Gn4C3 and Gn10B7 reacted with cuticle, muscle, esophagus, intestine, and the cervical sac of AdL3. In Western blotting analysis, Gn2C3, Gn4E9, and Gn5H1 reacted to 60-, 53-, 46-, and 41-kDa proteins; Gn4C3 reacted to the AdL3 protein of G. nipponicum (>42 kDa). Moreover, proteins purified using a mAb Gn4E9 immunoprecipitation method (sizes 60-, 53-, 46-, and 41-kDa) were used as antigens in ELISAs. A significant difference (P < 0.01) was shown between mouse sera infected with G. nipponicum and sera infected with Trichnella sp. or not infected. These results provide a rationale for evaluating esophageal proteins for the development of diagnostic methods for detecting G. nipponicum or Gnathostoma sp. infections.

Animals↗
PubMed2001

Metabolic alterations by clofibric acid in the formation of molecular species of phosphatidylcholine in rat liver.

The mechanism by which p-chlorophenoxyisobutyric acid (clofibric acid) induces striking changes in the proportion of the molecular species of phosphatidylcholine (PC) in rat liver was studied. Treatment of rats with clofibric acid strikingly increased the content of 1-palmitoyl-2-oleoyl (16:0-18:1) PC, but decreased the contents of 1-palmitoyl-2-docosahexaenoyl (16:0-22:6), 1-stearoyl-2-arachidonoyl (18:0-20:4), and 1-stearoyl-2-linoleoyl (18:0-18:2) PC; the drug did not change the content of 1-palmitoyl-2-arachidonoyl (16:0-20:4) PC. The mechanism underlying these changes has been investigated with regard to the in vivo formation of the molecular species of PC by: (i) de novo synthesis, (ii) reacylation, and (iii) methylation of phosphatidylethanolamine (PE). We found that (i) the incorporation of [3H]glycerol, which was injected intravenously, into 16:0-18:1 diacylglycerol (DG) and 16:0-18:1 PC was increased markedly by clofibric acid feeding without changing the substrate specificity of CDP-choline:DG cholinephosphotransferase, (ii) the in vivo formation of 16:0-18:1 and 16:0-20:4 PC from 1-16:0-[3H]glycerophosphocholine (GPC), which was injected intraportally, was increased markedly by clofibric acid feeding, and (iii) the incorporation of [14C]ethanolamine, which was injected intravenously into 16:0-22:6, 18:0-22:6, and 18:0-20:4 PC, was decreased by clofibric acid feeding; the extent of the decrease in 16:0-20:4 PC was less than that of 18:0-20:4 PC. It was concluded, therefore, that (i) clofibric acid selectively increased the content and proportion of 16:0-18:1 PC by enhancing both the CDP-choline pathway and the remodeling of the pre-existing PC molecule, and (ii) the drug kept the content of 16:0-20:4 PC unchanged by stimulating the remodeling of the pre-existing PC molecule, whereas the formation of other more long chain, polyunsaturated molecular species, such as 16:0-22:6, 18:0-22:6, and 18:0-20:4, was decreased owing to the suppression of PE methylation.

Acylation↗
PubMed2001

Developmental changes in 5-hydroxytryptamine-induced rhythmic activity in the spinal cord of rat fetuses in vitro.

The roles played by glycine- and glutamate-mediated synaptic transmission in the generation of 5-hydroxytryptamine (5-HT)-induced rhythmic activity were examined in isolated spinal cord preparations from fetal rats. Bath application of 5-HT (0.1-30 microM) evoked rhythmic activity in lumbar ventral roots at and after E14.5. Bath application of strychnine (5 microM), a glycine-receptor antagonist, reduced the frequency of the rhythmic activity to 37% of control at E14.5. Although, kynurenate (4 mM), a glutamate-receptor antagonist, had little effect at this stage, it completely abolished the 5-HT-induced rhythmic activity at and after E18.5, when strychnine had little effect on the frequency. These results indicate that, at and shortly after its onset, the rhythmic activity is driven mainly by glycinergic rather than glutamatergic excitatory synaptic inputs, but that the latter become dominant later on.

Animals↗
PubMed2001

Comparison of the elimination between perfluorinated fatty acids with different carbon chain length in rats.

Elimination in urine and feces was compared between four perfluorinated fatty acids (PFCAs) with different carbon chain length. In male rats, perfluoroheptanoic acid (PFHA) was rapidly eliminated in urine with the proportion of 92% of the dose being eliminated within 120 h after an intraperitoneal injection. Perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) was eliminated in urine with the proportions of 55, 2.0 and 0.2% of the dose, respectively. By contrast, four PFCAs were eliminated in feces with the proportion of less than 5% of the dose within 120 h after an injection. In female rats, the proportions of PFOA and PFNA eliminated in urine within 120 h were 80% and 51% of the dose, respectively, which were significantly higher compared with those in male rats. There was the tendency that PFCA with longer carbon chain length is less eliminated in urine in both male and female rats. Fecal elimination of PFCAs was not different between PFCAs in female rats and comparable to those in male rats. The rates of biliary excretion of PFCAs in male rats were slower than those in female rats. Sex-related difference in urinary elimination of PFOA was abolished when male rats had been castrated. On the contrary, treatment with testosterone suppressed the elimination of PFOA in urine in both castrated male rats and female rats. The effect of testosterone was in a time- and dose-dependent manner. These results suggest that PFCAs are distinguished by their carbon chain length by a renal excretion system, which is regulated by testosterone.

Animals↗
PubMed2001

Detection of cytokeratin 19 and 20 mRNA in peripheral and mesenteric blood from colorectal cancer patients and their prognosis.

To detect the presence of cancer cells in peripheral and mesenteric blood and to examine their relationship to prognosis in colorectal cancer patients undergoing curative surgery, we examined cytokeratin 19 and 20 mRNA in peripheral and mesenteric venous blood. Using reverse transcriptase polymerase chain reaction, cytokeratin 19 and 20 mRNA was amplified in peripheral and mesenteric blood samples obtained from 35 colorectal cancer patients who underwent curative surgery. Cytokeratin 19 or 20 mRNA in peripheral or mesenteric blood samples was detected in 18 of 35 cases (51%). There was no significant difference in Dukes' staging between the positive and negative groups. The median follow-up period was 56 months. In the positive group six patients (33%) showed recurrences. One patient (6%) showed recurrence in the negative group. The recurrence rate was significantly higher in the positive group than in the negative group. Five-year disease-free survival was significantly better in the negative group than in the positive group (94% vs. 65%). The detection of cytokeratin 19 or 20 mRNA in peripheral or mesenteric blood is thus associated with the prognosis for colorectal cancer patients undergoing curative surgery. Although the presence of these mRNAs in blood samples is a prognostic marker, the clinical utility of this assay is questionable because of the low recurrence rate in the positive group.

Adult↗
PubMed2001

Crystallization and secondary-structure determination of a protein of the Lrp/AsnC family from a hyperthermophilic archaeon.

A protein belonging to the Lrp/AsnC transcription-factor family, pot1216151, from the hyperthermophilic archaeon Pyrococcus sp. OT3 was crystallized. In Escherichia coli, leucine-responsive protein (Lrp) and AsnC regulate a number of metabolic genes. The crystals of pot1216151 diffracted to 2.3 A using a conventional X-ray source and to 1.8 A using a synchrotron-radiation source. The space group was identified to be P3(1)21 or P3(2)21, with unit-cell parameters a = b = 96.9, c = 98.5 A. In combination with diffraction data obtained from K(2)[Pt(CN)(6)] and K(AuCl(4)) derivatives, an electron-density map was calculated at a resolution of 3.0 A. Four monomers were identified in the asymmetric unit, with four beta-strands and two alpha-helices in each monomer.

Archaeal Proteins↗
PubMed2001

Effects of dehydroepiandrosterone on oleic acid formation in the liver of rats, mice and guinea pigs.

The purpose of the present study is to answer the question of whether there is a species difference in the effects of a pharmacological dose of dehydroepiandrosterone (DHEA) on the enzymes that participate in oleic acid (18:1) formation in the liver. Feeding a diet containing 0.5% (w/w) DHEA for 14 days markedly increased the activities of acyl-coenzyme A (CoA) synthetase, palmitoyl-CoA chain elongase and stearoyl-CoA desaturase in the liver of rats and mice. These enzyme activities, however, were not changed by DHEA in guinea pigs. The treatments of rats and mice with DHEA markedly increased proportions of 18:1 in hepatic lipids, especially phosphatidylcholine (selectively at C-2 position), triacylglycerol and cholesterol ester. DHEA caused no significant changes in acyl compositions of hepatic lipids of guinea pigs. The levels of DHEA or dehydroepiandrosterone sulfate (DHEAS) were markedly increased in serum and livers by DHEA administration to rats, mice and guinea pigs. High correlations were observed between hepatic levels of DHEA or DHEAS and stearoyl-CoA desaturase activities in rats. These results indicate that there are species differences in the inducing effects of DHEA or DHEAS on hepatic formation of 18:1 and that guinea pigs lack the machinery to induce the enzymes.

Acetyltransferases↗
PubMed2001

The first host record of trichinosis in a red fox, Vulpes vulpes japonica, from Aomori Prefecture, northern Honshu, Japan.

A case of wildlife trichinosis was found in a red fox (Vulpes vulpes japonica) captured at Rokkasho, Aomori Prefecture on November 27, 1998. Trichinella larvae were obtained from almost all of the muscle tissues except for the masseter. The highest number of larvae per gram of tissue was found in the muscles of the gluteal region and throat. The lowest number was found in the diaphragm and tongue. Trichina cysts within the muscle fibers had groups of fatty cells at the poles, and minimal tissue reaction was observed around the cyst. No calcification was found in the cyst. These morphological findings suggested that the considerable time had elapsed since the invasion. This is the first case of trichinosis in a red fox in Japan.

Animals↗
PubMed2001

Analysis of a growth-promoting factor for Babesia caballi cultivation.

Serum-free media were examined to culture Babesia caballi. Daigo's T (DT) basal medium supplemented with Daigo's GF21 (GF21) or GIT medium, which already contains GF21, supported the parasite propagation at 37 C in a humidified atmosphere under 5% CO2 in air. Growth of B. caballi was dependent of the suitable concentration (10-20%) of GF21. Therefore, GF21 was suggested as the growth-promoting factor for B. caballi. However, GIT medium did not support the growth of parasites from cryopreserved stabilates, and serum supplementation was essential for the retrieval of parasites.

Animals↗
PubMed2000

Three-dimensional solution structure of oryzacystatin-I, a cysteine proteinase inhibitor of the rice, Oryza sativa L. japonica.

The three-dimensional structure of oryzacystatin-I, a cysteine proteinase inhibitor of the rice, Oryza sativa L. japonica, has been determined in solution at pH 6.8 and 25 degrees C by (1)H and (15)N NMR spectroscopy. The main body (Glu13-Asp97) of oryzacystatin-I is well-defined and consists of an alpha-helix and a five-stranded antiparallel beta-sheet, while the N- and C-terminal regions (Ser2-Val12 and Ala98-Ala102) are less defined. The helix-sheet architechture of oryzacystatin-I is stabilized by a hydrophobic cluster formed between the alpha-helix and the beta-sheet and is considerably similar to that of monellin, a sweet-tasting protein from an African berry, as well as those of the animal cystatins studied, e.g., chicken egg white cystatin and human stefins A and B (also referred to as human cystatins A and B). Detailed structural comparison indicates that oryzacystatin-I is more similar to chicken cystatin, which belongs to the type-2 animal cystatins, than to human stefins A and B, which belong to the type-1 animal cystatins, despite different loop length.

Amino Acid Sequence↗
PubMed2000

Formation of the central pattern generator for locomotion in the rat and mouse.

It is well known that in the neonatal rat spinal cord preparation, alternating rhythmic bursts in the left and right ventral roots in a given lumbar segment can be induced by bath-application of N-methyl-D-aspartate or 5-hydroxytryptamine. Alternation between L2 and L5 ventral roots on the same side, representing the activity of flexor and extensor muscles, respectively, can be observed as well. In the prenatal period in the rat, alternation between the left and right ventral roots is established between embryonic day (E) 16.5 and E18.5. The alternation between the L2 and L5 ventral roots emerges at E20.5. Recent findings show that locomotor-like rhythmic activity with similar characteristics can be induced in the neonatal mouse preparation. In the lumbar spinal cord in the neonatal mouse, it is likely that the rhythm-generating network is distributed throughout the lumbar region with a rostro-caudal gradient, a situation similar to that in the neonatal and fetal rat spinal cord. With this review we hope to highlight the dramatic changes that neuronal networks generating locomotor-like activity undergo during the prenatal development of the rat. Moreover, the distribution of the neuronal network generating the locomotor rhythm in the neonatal rat and mouse spinal cord is compared.

Animals↗
PubMed2000

Oxidative stress abolishes leptomycin B-sensitive nuclear export of transcription repressor Bach2 that counteracts activation of Maf recognition element.

The mammalian transcription activator Nrf2 plays critical roles in executing oxidative stress response by binding to the regulatory DNA sequence Maf recognition element. Bach2 is an Nrf2-related transcription repressor and a tissue-specific partner of the Maf oncoprotein family. We show here how Bach2 is regulated by an oxidative stress-sensitive conditional nuclear export. In cultured cells, Bach2 was localized in cytoplasm through its C-terminal evolutionarily conserved cytoplasmic localization signal (CLS). The CLS directed leptomycin B-sensitive nuclear export of reporter proteins, suggesting its dependence on the nuclear exporter Crm1/exportin 1. However, the CLS sequence does not bear a resemblance to the leucine-rich class of nuclear export signal, and mutagenesis analysis indicated that a stretch of nonhydrophobic amino acids is essential for its activity. Oxidative stressors aborted the CLS activity and induced nuclear accumulation of Bach2. Whereas oxidative stress is known to activate MARE-dependent transcription, overexpression of Bach2 in cultured cells silenced the inducibility of MARE. The results suggest that Bach2 mediates nucleocytoplasmic communication to couple oxidative stress and transcription repression in mammalian cells.

Amino Acid Sequence↗
PubMed2000

5-Hydroxytryptamine-induced locomotor rhythm in the neonatal mouse spinal cord in vitro.

We examined the 5-hydroxytryptamine (5-HT)-induced locomotor rhythm in isolated spinal cord preparations taken from neonatal mice on postnatal day (P) 0-3. Motor activity was recorded from L2 and L5 ventral roots. Bath application of 5-HT (15-100 microM) evoked rhythmic bursts that alternated between the two sides, and the bursts in the L2 ventral root alternated with those in the ipsilateral L5 ventral root. After transection of the mid-lumbar cord, the locomotor rhythm in L2 persisted, while that in the L5 ventral root was abolished. This suggests that the upper lumbar region has a greater ability to generate a locomotor rhythm than the lower lumbar spinal cord. Kynurenate, a broad-spectrum glutamate receptor antagonist, blocked the 5-HT-induced locomotor rhythm indicating that ionotropic glutamate receptors are required for the rhythm to be generated.

Animals↗
PubMed2000

A nuclear export signal in the N-terminal regulatory domain of IkappaBalpha controls cytoplasmic localization of inactive NF-kappaB/IkappaBalpha complexes.

Appropriate subcellular localization is crucial for regulation of NF-kappaB function. Herein, we show that latent NF-kappaB complexes can enter and exit the nucleus in preinduction states. The nuclear export inhibitor leptomycin B (LMB) sequestered NF-kappaB/IkappaBalpha complexes in the nucleus. Using deletion and site-directed mutagenesis, we identified a previously uncharacterized nuclear export sequence in residues 45-54 of IkappaBalpha that was required for cytoplasmic localization of inactive complexes. This nuclear export sequence also caused nuclear exclusion of heterologous proteins in a LMB-sensitive manner. Importantly, a LMB-insensitive CRM1 mutant (Crm1-K1) abolished LMB-induced nuclear accumulation of the inactive complexes. Moreover, a cell-permeable p50 NF-kappaB nuclear localization signal peptide also blocked these LMB effects. These results suggest that NF-kappaB/IkappaBalpha complexes shuttle between the cytoplasm and nucleus by a nuclear localization signal-dependent nuclear import and a CRM1-dependent nuclear export. The LMB-induced nuclear complexes could not bind DNA and were inaccessible to signaling events, because LMB inhibited NF-kappaB activation without affecting the subcellular localization of upstream kinases IKKbeta and NIK. Our findings indicate that the dominant nuclear export over nuclear import contributes to the largely cytoplasmic localization of the inactive complexes to achieve efficient NF-kappaB activation by extracellular signals.

Amino Acid Motifs↗
PubMed2000

Induction by perfluorinated fatty acids with different carbon chain length of peroxisomal beta-oxidation in the liver of rats.

The potency of the induction of peroxisomal beta-oxidation was compared between perfluorinated fatty acids (PFCAs) with different carbon chain lengths in the liver of male and female rats. In male rats, perfluoroheptanoic acid (PFHA) has little effect, although perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) potentially induced the activity. By contrast, PFHA and PFOA did not induce the activity of peroxisomal beta-oxidation in the liver of female rats while PFNA and PFDA effectively induced the activity. The induction of the activity by these PFCAs was in a dose-dependent manner, and there is a highly significant correlation between the induction and hepatic concentrations of PFCAs in the liver regardless of their carbon chain lengths. These results strongly suggest that the difference in their chemical structure is not the cause of the difference in the potency of the induction. Hepatic concentrations of PFOA and PFNA was markedly higher in male compared with female rats. Castration of male rats reduced the concentration of PFNA in the liver and treatment with testosterone entirely restored the reduction. In contrast to the results obtained from the in vivo experiments, the activity of peroxisomal beta-oxidation was induced by PFDA and PFOA to the same extent in cultured hepatocytes prepared from both male and female rats. These results, taken together, indicate that difference in accumulation between PFCAs in the liver was responsible for the different potency of the induction of peroxisomal beta-oxidation between PFCAs with different carbon chain lengths and between sexes.

Acyl-CoA Oxidase↗
PubMed2000

Influence of a fat on muscle oxygenation measurement using near-IR spectroscopy: quantitative analysis based on two-layered phantom experiments and Monte Carlo simulation.

The influence of a subcutaneous fat layer on measurement of muscle oxygenation using near-IR spectroscopy was quantitatively investigated by two-layered phantom experiments and Monte Carlo simulations, with the aim of developing an algorithm that can correct this influence. The phantom consisted of a fat-like layer, which was a mixture of agar and titanium dioxide powder, and a muscle-like layer, which was suspension of washed bovine blood in Intralipid solution. An LED with 760 and 840 nm elements was used as an optical source, and the backscattered light was detected by photodiodes at source-detector distances of 20, 30 and 40 mm. The relationships between changes in optical density and blood concentrations were obtained at fat-like layer thicknesses of 0.5,10 and 15 mm under fully oxygenated and fully deoxygenated states. It was experimentally found that the change in optical density is significantly decreased and the linearity of measurement characteristics is clearly distorted by the presence of a fat layer. In the simulations, normalized light reflectance and mean optical pathlength in a muscle layer were calculated. The simulation results of the light reflectance agreed well with the experimental results. When the absorption in a muscle layer was relatively high, the mean optical pathlength in the muscle layer, or the measurement sensitivity, was not so dependent on the absorption. Therefore, the modified Beer-Lambert law can still be applied to estimate changes in muscle absorption from changes in optical density, even when a fat layer is involved. The results of simulation also suggested that the influence of a fat layer can be eliminated by correcting the measurement sensitivity using the fat layer thickness.

Adipose Tissue↗
PubMed2000

Developmentally regulated activity of CRM1/XPO1 during early Xenopus embryogenesis.

In this work, we have investigated the role of CRM1/XPO1, a protein involved in specific export of proteins and RNA from the nucleus, in early Xenopus embryogenesis. The cloning of the Xenopus laevis CRM1, XCRM1, revealed remarkable conservation of the protein during evolution (96.7% amino acid identity between Xenopus and human). The protein and mRNA are maternally expressed and are present during early embryogenesis. However, our data show that the activity of the protein is developmentally regulated. Embryonic development is insensitive to leptomycin B, a specific inhibitor of CRM1, until the neurula stage. Moreover, the nuclear localization of CRM1 changes concomitantly with the appearance of the leptomycin B sensitivity. These data suggest that CRM1, present initially in an inactive form, becomes functional before the initiation of the neurula stage during gastrula-neurula transition, a period known to correspond to a critical transition in the pattern of gene expression. Finally, we confirmed the gastrula-neurula transition-dependent activation of CRM1 by pull-down experiments as well as by the study of the intracellular localization of a green fluorescent protein tagged with a nuclear export signal motif during early development. This work showed that the regulated activity of CRM1 controls specific transitions during normal development and thus might be a key regulator of early embryogenesis.

Amino Acid Sequence↗