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T Kudo

Publications and source records attributed to T Kudo.

At least 37 records · Page 2Linked to original sources

Differential effects of thiopental on methacholine- and serotonin-induced bronchoconstriction in dogs.

BACKGROUND: Thiopental sometimes causes bronchospasm during induction of anaesthesia. In addition, we have reported previously that thiopental produced transient bronchospasm, which was blocked by atropine pretreatment, and worsened histamine-induced bronchoconstriction in dogs. Previous in vitro reports suggest that synthesis of contractile cyclooxygenase products, such as thromboxane A(2), may be involved in the mechanism of bronchospasm. However, the in vivo spastic effects have not been defined comprehensively. METHODS: Twenty-seven mongrel dogs were anaesthetized with pentobarbital. Bronchoconstriction was elicited with methacholine (0.5 microg kg(-1)+5.0 microg kg(-1) min(-1); Mch group, n=7) or serotonin (10 microg kg(-1)+1 mg kg(-1) h(-1); 5HT group, n=20), and assessed as percentage changes in bronchial cross-sectional area (BCA, basal=100%) using a bronchoscope. In the 5HT group, dogs were subdivided into four groups of five each: S-5HT, I-5HT, 5HT-S and 5HT-A. In the S-5HT and I-5HT groups, 30 min before serotonin infusion dogs were given saline and indomethacin respectively at 5 mg kg(-1) i.v. In all groups, 30 min after bronchoconstrictor infusion started, dogs were given thiopental at doses between 0 (saline) and 20 mg kg(-1). In the 5HT-S and 5HT-A groups, dogs were given saline or atropine 0.2 mg kg(-1) i.v. 5 min after thiopental 20 mg kg(-1). RESULTS: Methacholine and serotonin reduced BCA by about 50 and 40% respectively. Thiopental 20 mg kg(-1) increased and decreased BCA by about 20 and 10% in the Mch and 5HT groups respectively. Indomethacin and atropine did not attenuate the potentiation of serotonin bronchoconstriction produced by thiopental. CONCLUSION: The present study indicates that thiopental may attenuate or worsen bronchoconstriction induced by muscarinic or serotonin receptor stimulation, respectively. The synthesis of contractile cyclooxygenase products and cholinergic stimulation may not be involved in the contractile effect of thiopental on serotonin bronchoconstriction.

Anesthetics, Intravenous↗

Isotope effects and intermediates in the reduction of NO by P450(NOR).

The mechanism of the heme-thiolate-dependent NADH-NO reductase (P450(NOR)) from Fusarium oxysporum was investigated by kinetic isotope effects including protio, [4S-2H]-, [4R-2H]-, [4,4(2)H(2)]-NADH and stopped-flow measurements. The respective kinetic isotope effects were measured at high NO concentrations and were found to be 1.7, 2.3 and 3.8 indicating a rate-limitation at the reduction step and a moderate stereoselectivity in binding of the cofactor NADH. In a different approach the kinetic isotope effects were determined directly for the reaction of the Fe(III)-NO complex with [4R-2H]- and [4S-2H]-NADH by stopped-flow spectroscopy. The resulting isotope effects were 2.7+/-0.4 for the R-form and 1.1+/-0.1 for the S-form. In addition the 444 nm intermediate could be chemically generated by addition of an ethanolic borohydride solution to the ferric-NO complex at -10 degrees C. In pulse radiolysis experiments a similar absorbing species could be observed when hydroxylamine radicals were generated in the presence of Fe (III) P450(NOR). Based on these results we postulate hydride transfer from NADH to the ferric P450-NO complex resulting in a ferric hydroxylamine-radical or ferryl hydroxylamine-complex and this step, as indicated by the kinetic isotope effects, to be rate-limiting at high concentrations of NO. However, at low concentrations of NO the decay of the 444 nm species becomes the rate-limiting step as envisaged by stopped-flow and optical kinetic measurements in a system in which NO was continuously generated. The last step in the catalytic cycle may proceed by a direct addition of the NO radical to the Fe-hydroxylamine complex or by electron transfer from the NO radical to the ferric-thiyl moiety in analogy to the postulated mechanisms of prostacyclin and thromboxane biosynthesis by the corresponding P450 enzymes. The latter process of electron transfer could then constitute a common step in all heme-thiolate catalyzed reactions.

Cytochrome P-450 Enzyme System↗

Doppler ultrasound monitoring for detection of microembolic signals in peripheral arteries.

OBJECTIVE: to use Doppler ultrasound to detect peripheral microemboluation. METHODS: standard Transcranial Doppler equipment was used to peripheral detect peripheral embolic high intensity transient signals (HITSs) in a pig model following injection of microparticles and atheroma, and in 23 patients who underwent open repair of an abdominal aortic aneurysm (AAA), six patients with blue toe syndrome and 10 age matched healthy subjects. RESULTS: the pig study showed increasing signal intensity with particle size. Particles of 100 (n=24), 200 (n=17), and 400 microm (n=31) elicited 14, 25, 33 dB signals, respectively (p<0.05). During AAA surgery, the intensity (median) of HITSs before clamping (n=226) and after declamping (n=1216) were 14, and 20dB, respectively (p<0.001). Quite a few HITSs were detected after surgery. In patients with blue toe syndrome, a total of 63 HITSs could be detected, and the frequency of HITSs (median: 5.72/30min) was significantly higher than that in patients with AAA before surgery (0.065/30min) (p<0.001). CONCLUSIONS: Doppler ultrasound technique may be a clinically useful test to guide the treatment of patients at risk of distal atheroembolic events.

Aged↗

Effects of n-3 polyunsaturated fatty acids on dermatitis in NC/Nga mice.

The administration of n-3 polyunsaturated fatty acids (PUFAs) is known to be effective against allergic diseases by suppressing the production of eicosanoids derived from arachidonic acid. To investigate the mechanisms and efficacy of n-3 PUFA treatment in patients with atopic dermatitis (AD), we administered four different formulas of alpha-linolenic acid for 6 weeks in an AD model using NC/Nga mice. According to the doses of alpha-linolenic acid given, the levels of alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid in the red blood cell membranes increased while the levels of linoleic acid and arachidonic acid decreased. However, there was no significant difference among the four dose groups in clinical skin severity score, histopathological findings of skin lesions, or levels of total plasma IgE. Moreover, there was no significant difference in the production of leukotriene B(4) and Leukotriene C(4) from skin lesions after stimulation with A23187 among the groups, although the production of prostaglandin E(2) (PGE(2)) was significantly reduced and skin blood flow in the ear was significantly higher in the group given the highest dose of alpha-linolenic acid. Our results suggest that the administration of alpha-linolenic acid can change the fatty acid composition, PGE(2) production, and skin blood flow but may not prevent the development of dermatitis in NC/Nga mice.

Animals↗

Elevated blood flow resistance in uterine arteries of women with unexplained recurrent pregnancy loss.

BACKGROUND: Uterine perfusion appears to regulate uterine receptivity. However, vascular changes in recurrent pregnancy loss (RPL) remain poorly studied. METHODS: One hundred and twenty one women were enrolled into this study: normal women with sterility caused by male factor (control group: n = 72) and women with RPL (n = 49). Women with uterine anomaly, impaired glucose tolerance, abnormal thyroid function, or anti-phospholipid antibodies were excluded from the study. In the mid-luteal phase of a non-pregnant cycle, transvaginal pulsed Doppler ultrasonography of the uterine artery was performed. Uterine arterial pulsatility index (PI), endometrial thickness, serum estradiol, progesterone, and nitrite/nitrate concentrations were determined. RESULTS: In the RPL group, the PI in the uterine artery of women with antinuclear antibodies was significantly higher than that of women without antinuclear antibodies (P < 0.05). Among women without antinuclear antibodies, the mean (+/-SD) uterine artery PI in the RPL group (2.44 +/- 0.41) was also significantly higher than in the control group (2.19 +/- 0.40; P < 0.01). The PI was inversely correlated with serum progesterone levels (r = -0.47, P < 0.01). CONCLUSIONS: Elevated uterine arterial impedance is associated with RPL. Pulsed Doppler ultrasonography is useful in identifying women with unexplained RPL who have impaired uterine circulation.

Abortion, Habitual↗

Rhabdomyosarcoma (botryoid sarcoma) of the urinary bladder in a Maltese.

A urinary bladder tumour was diagnosed in a two-year-old female Maltese with haematuria and pollakiuria on the basis of ultrasonography and pneumocystography findings. The mass was resected, and the bladder was preserved at surgery. Histological and immunohistochemical examination confirmed the tumour to be a rhabdomyosarcoma, which has rarely been reported in small breeds of dog. There was no recurrence of the tumour at the original site in the urinary bladder two months later, when the dog died due to metastasis to the liver. This is believed to be the first report of bladder rhabdomyosarcoma in a Maltese.

Animals↗

Disturbed activation of endoplasmic reticulum stress transducers by familial Alzheimer's disease-linked presenilin-1 mutations.

Recent studies have shown independently that presenilin-1 (PS1) null mutants and familial Alzheimer's disease (FAD)-linked mutants should both down-regulate signaling of the unfolded protein response (UPR). However, it is difficult to accept that both mutants possess the same effects on the UPR. Furthermore, contrary to these observations, neither loss of PS1 and PS2 function nor expression of FAD-linked PS1 mutants were reported to have a discernable impact on the UPR. Therefore, re-examination and detailed analyses are needed to clarify the relationship between PS1 function and UPR signaling. Here, we report that PS1/PS2 null and dominant negative PS1 mutants, which are mutated at aspartate residue 257 or 385, did not affect signaling of the UPR. In contrast, FAD-linked PS1 mutants were confirmed to disturb UPR signaling by inhibiting activation of both Ire1alpha and ATF6, both of which are endoplasmic reticulum (ER) stress transducers in the UPR. Furthermore, PS1 mutants also disturbed activation of PERK (PKR-like ER kinase), which plays a crucial role in inhibiting translation during ER stress. Taken together, these observations suggested that PS1 mutations could affect signaling pathways controlled by each of the respective ER-stress transducers, possibly through a gain-of-function.

Alzheimer Disease↗

Abnormal longitudinal, base-to-apex myocardial perfusion gradient by quantitative blood flow measurements in patients with coronary risk factors.

BACKGROUND: A longitudinal, base-to-apex myocardial perfusion gradient has been described in patients with coronary artery disease (CAD) and was attributed to diffuse coronary luminal narrowing. We asked whether an abnormal perfusion gradient also existed in patients without CAD but with coronary risk factors. We measured myocardial blood flow (MBF) with (13)N-ammonia and PET at rest and during hyperemia in patients with coronary risk factors but without CAD. METHODS AND RESULTS: Regional MBF was measured in absolute units with (13)N-ammonia and PET at rest and during dipyridamole hyperemia in 36 patients with coronary risk factors (age, 55+/-10 years) and in 36 age-matched (age, 53+/-10 years) and in 28 young (age, 25+/-5 years) normal subjects. MBF was determined globally, for each of the 3 coronary territories, and in the mid and mid-to-apical sections of the left ventricle (LV). Myocardial perfusion on qualitative analysis was normal at rest and during hyperemia, and no flow defects were present. MBF in absolute units was similar in the 3 coronary territories. However, hyperemic MBFs in the mid-to-apical LV section were lower than in the mid LV section in the "at-risk" group (2.04+/-0.61 versus 1.71+/-0.40 mL. min(-1). g(-1); P<0.004) but not in the age-matched or in the young normal subjects. CONCLUSIONS: The abnormal longitudinal, base-to-apex perfusion gradient observed during dipyridamole MBF suggests the presence of a functional and/or structural alteration of the coronary circulation associated with coronary risk factors, possibly reflecting developing coronary atherosclerosis or preclinical CAD.

Aged↗

Vascular endothelial growth factor-C expression and its relationship to pelvic lymph node status in invasive cervical cancer.

Vascular endothelial growth factor-C (VEGF-C) has been implicated in lymphangiogenesis, the process of new lymphatics formation. The present study investigated VEGF-C mRNA expression in invasive cervical cancer tissue. Additionally, the association of VEGF-C mRNA with clinicopathological features was examined. VEGF-C mRNA expression was assessed by reverse transcription-polymerase chain reaction using beta-action as an internal control. 75 patients presenting with invasive cervical cancer were included in the trial. VEGF-C mRNA expression was markedly higher in tumours in which pelvic lymph node metastasis was diagnosed by magnetic resonance (MR) imaging (P = 0.002). 53 patients displaying stage Ib-IIb cervical cancer underwent radical hysterectomy and pelvic lymphadenectomy. VEGF-C expression was significantly higher in tumours exhibiting deep stromal invasion, pelvic lymph node metastasis and lymph-vascular space involvement (P = 0.016, P = 0.006 and P = 0.036, respectively). Multivariate analysis revealed VEGF-C mRNA expression to be the sole independent factor influencing pelvic lymph node metastasis. Subjects demonstrating VEGF-C mRNA expression displayed significantly poorer prognoses than those lacking VEGF-C mRNA expression (P = 0.049). These findings provide evidence supporting the involvement of VEGF-C expression in the promotion of lymph node metastasis in cervical cancer. Furthermore, examination of VEGF-C expression in biopsy specimens may be beneficial in the prediction of pelvic lymph node metastasis.

Cervix Uteri↗

The unfolded protein response and Alzheimer's disease.

Disruption of calcium homeostasis, inhibition of protein glycosylation, and reduction of disulfide bonds provoke accumulation of unfolded protein in the endoplasmic reticulum (ER), and are therefore a type of 'ER stress'. Normal cells respond to ER stress by increasing transcription of genes encoding ER-resident chaperones such as GRP78/BiP, GRP94 and protein disulfide isomerase to facilitate protein folding. This induction system is termed the unfolded protein response. Familial Alzheimer's disease-linked presenilin-1 (PS1) mutation downregulates the unfolded protein response and leads to vulnerability to ER stress. The mechanisms by which mutant PS1 affects the ER stress response are attributed to the inhibited activation of ER stress transducers such as IRE1, PERK and ATF6.

Alzheimer Disease↗

Crystallization and preliminary X-ray studies of meso-2,3-butanediol dehydrogenase from Klebsiella pneumoniae IAM1063.

Meso-2,3-butanediol dehydrogenase (meso-BDH) has been crystallized and preliminary X-ray crystallographic characterization of meso-BDH crystals has been performed. Single crystals of meso-BDH were prepared in two forms by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant. Form I crystals belong to space group C2, with unit-cell parameters a = 215.5, b = 79.4, c = 134.8 A, beta = 98.22 degrees, and form II crystals belong to space group P2(1), with unit-cell parameters a = 69.16, b = 109.78, c = 127.28 A, beta = 102.29 degrees. The crystals diffracted to 2.0 and 1.7 A resolutions, respectively, using synchrotron radiation.

Alcohol Oxidoreductases↗

Effects of nociceptinNH2 and [Nphe1]nociceptin(1-13)NH2 on rat brain noradrenaline release in vivo and in vitro.

We have investigated the effects of nociceptin/orphanin FQ (NC) receptor agonist NCNH2 and a competitive NC receptor antagonist, [Nphe1]NC(1-13)NH2 on noradrenaline (NA) release in vivo using microdialysis in freely moving animals and in vitro from cerebrocortical slices. One nmol of NCNH2 injected into rat locus coeruleus inhibited NA release from the prefrontal cortex (E(max) 27.4+/-5.7% 30 min after injection) which was partially (33%) reversed by 100 nmol of [Nphe1]NC(1-13)NH2. In cerebrocortical slices NCNH2 inhibited NA release in a concentration-dependent manner (EC50 12 nM, E(max) 29.4%) that was reversed by [Nphe1]NC(1-13)NH2. In both preparations, [Nphe1]NC(1-13)NH2 per se was inactive. These data demonstrate an inhibition of NA release by NCNH2 in a [Nphe1]NC(1-13)NH2 sensitive manner in both in vivo brain microdialysis and in vitro cerebrocortical slices studies in rats.

Animals↗

Molecular cloning and characterization of UDP-GlcNAc:lactosylceramide beta 1,3-N-acetylglucosaminyltransferase (beta 3Gn-T5), an essential enzyme for the expression of HNK-1 and Lewis X epitopes on glycolipids.

A new member of the UDP-N-acetylglucosamine:beta-galactose beta1,3-N-acetylglucosaminyltransferase (beta3Gn-T) family having the beta3Gn-T motifs was cloned from rat and human cDNA libraries and named beta3Gn-T5 based on its position in a phylogenetic tree. We concluded that beta3Gn-T5 is the most feasible candidate for lactotriaosylceramide (Lc(3)Cer) synthase, an important enzyme which plays a key role in the synthesis of lacto- or neolacto-series carbohydrate chains on glycolipids. beta3Gn-T5 exhibited strong activity to transfer GlcNAc to glycolipid substrates, such as lactosylceramide (LacCer) and neolactotetraosylceramide (nLc(4)Cer; paragloboside), resulting in the synthesis of Lc(3)Cer and neolactopentaosylceramide (nLc(5)Cer), respectively. A marked decrease in LacCer and increase in nLc(4)Cer was detected in Namalwa cells stably expressing beta3Gn-T5. This indicated that beta3Gn-T5 exerted activity to synthesize Lc(3)Cer and decrease LacCer, followed by conversion to nLc(4)Cer via endogenous galactosylation. The following four findings further supported that beta3Gn-T5 is Lc(3)Cer synthase. 1) The beta3Gn-T5 transcript levels in various cells were consistent with the activity levels of Lc(3)Cer synthase in those cells. 2) The beta3Gn-T5 transcript was presented in various tissues and cultured cells. 3) The beta3Gn-T5 expression was up-regulated by stimulation with retinoic acid and down-regulated with 12-O-tetradecanoylphorbol-13-acetate in HL-60 cells. 4) The changes in beta3Gn-T5 transcript levels during the rat brain development were determined. Points 2, 3, and 4 were consistent with the Lc(3)Cer synthase activity reported previously.

Amino Acid Sequence↗

Large-scale domain movements and hydration structure changes in the active-site cleft of unligated glutamate dehydrogenase from Thermococcus profundus studied by cryogenic X-ray crystal structure analysis and small-angle X-ray scattering.

Here we describe the large-scale domain movements and hydration structure changes in the active-site cleft of unligated glutamate dehydrogenase. Glutamate dehydrogenase from Thermococcus profundus is composed of six identical subunits of M(r) 46K, each with two distinct domains of roughly equal size separated by a large active-site cleft. The enzyme in the unligated state was crystallized so that one hexamer occupied a crystallographic asymmetric unit, and the crystal structure of the hexamer was solved and refined at a resolution of 2.25 A with a crystallographic R-factor of 0.190. In that structure, the six subunits displayed significant conformational variations with respect to the orientations of the two domains. The variation was most likely explained as a hinge-bending motion caused by small changes in the main chain torsion angle of the residue composing a loop connecting the two domains. Small-angle X-ray scattering profiles both at 293 and 338 K suggested that the apparent molecular size of the hexamer was slightly larger in solution than in the crystalline state. These results led us to the conclusion that (i) the spontaneous domain motion was the property of the enzyme in solution, (ii) the domain motion was trapped in the crystallization process through different modes of crystal contacts, and (iii) the magnitude of the motion in solution was greater than that observed in the crystal structure. The present cryogenic diffraction experiment enabled us to identify 1931 hydration water molecules around the hexamer. The hydration structures around the subunits exhibited significant changes in accord with the degree of the domain movement. In particular, the hydration water molecules in the active-site cleft were rearranged markedly through migrations between specific hydration sites in coupling strongly with the domain movement. We discussed the cooperative dynamics between the domain motion and the hydration structure changes in the active site of the enzyme. The present study provides the first example of a visualized hydration structure varying transiently with the dynamic movements of enzymes and may form a new concept of the dynamics of multidomain enzymes in solution.

Binding Sites↗

CD15 expression in mature granulocytes is determined by alpha 1,3-fucosyltransferase IX, but in promyelocytes and monocytes by alpha 1,3-fucosyltransferase IV.

The CD15 carbohydrate epitope is expressed in mature human neutrophils, monocytes, and promyelocytes. We aimed to determine the alpha1,3-fucosyltransferase responsible for the expression of CD15 in each subpopulation of leukocytes. Three alpha1,3-fucosyltransferases, FUT4, FUT7, and FUT9, are expressed in human leukocytes. We demonstrated that FUT9 exhibits 20-fold stronger activity for CD15 synthesis than FUT4, whereas FUT4 exhibits 4.5-fold stronger activity for CDw65 synthesis than FUT9. By competitive reverse transcriptase-polymerase chain reaction, FUT9 was found to be strongly expressed in mature granulocytes and peripheral blood mononuclear cell, but not in monocytes. CD34(+) and CD15(+) cells in cord blood and myeloid cell lines (HL-60 and U937) did not express FUT9 at all. FUT4 transcripts were ubiquitously expressed in all blood cells and all cultured cell lines, with HL-60 and U937 cells in particular expressing a number of FUT4 transcripts. Transfection of the FUT9 gene into Jurkat and U937 cells demonstrated that FUT9 has the potential to express CD15 in myeloid and lymphoid cells. These findings suggest that the expression of CD15 in mature granulocytes is directed by FUT9, whereas it is determined in promyelocytes and monocytes by FUT4. Measurement of CD15 synthesizing activity in cell homogenates of each cell population using the polylactosamine acceptor further supported these conclusions.

Antigens, CD↗

The expression of pregnane X receptor and its target gene, cytochrome P450 3A1, in perinatal mouse.

Recently, pregnane X receptor (PXR) has been described to mediate the genomic effects of several steroid hormones, such as progesterone (P), glucocorticoid (Dex), pregnenolone (Preg), and xenobiotics through the cytochrome P-450 3A gene family (CYP3A), which are monooxygenases, responsible for the oxidative metabolism of some endogenous substrates and xenobiotics. In the present study, we used a transient transfection reporter gene expression assay of COS-7 cells to demonstrate that P, Dex and Preg significantly stimulate PXR-mediated transcription at relatively high concentration comparable with that of progesterone near term pregnancy. In yeast two-hybrid protein interaction assay, PXR interacted with nuclear receptor coactivator proteins, SRC1, RIP140, and SUG1 in a ligand-dependent manner. The expression of PXR mRNA was observed in the liver, intestine, uterus, ovary and placenta. The expressions of PXR mRNA in the liver and ovary increased towards term about fifty-fold compared with that of non-pregnancy and decreased postpartum. Its expression in the placenta was not drastically changed towards term. CYP3A, a target gene of PXR, was also expressed in the liver, ovary, and placenta. The expressions of CYP3A mRNA as well as PXR in the liver and ovary increased about 20-fold during prenatal period. These data suggest that PXR may play certain roles in perinatal period, possibly in the protection of the feto-maternal system from the toxic effect of endogenous steroids and foreign substrates.

Animals↗

Nucleotide sequence analysis of a human monoclonal antibody TONO-1 with cytotoxic potential for T-leukemia/lymphoma cells.

A human monoclonal antibody (HuMab) TONO-1 (IgM, lambda) recognizes cell surface antigens associated primarily with human T-leukemia/lymphoma cells. In this study, we investigated the reactivity against T-leukemia/lymphoma cells in detail, cytotoxic potential and primary nucleotide and deduced amino acid sequences of the rearranged heavy and light chains of the HuMab TONO-1. Expression of the molecules (TONO-1 Ags) detected by a HuMab TONO-1 was significantly heterogeneous even in the same T-leukemia/lymphoma cell lines HPB-MLT and MOLT-4F. The flow cytometric curves showed an unusual broad-based spread of fluorescence intensity. HuMab TONO-1 was shown to have the ability to kill the T-leukernia/lymphoma cells efficiently in the presence of rabbit complements. However, HuMab TONO-1 did not demonstrate significant antibody-dependent cellular cytotoxic activity. Furthermore, HuMab TONO-1 heavy and light chain variable regions were cloned, sequenced and analyzed. HuMab TONO-1 uses a V(H) gene member of the V(H)IV gene family V(H)71-4, and is productively rearranged with the germ line D(H) gene D(XP')1, and the germ line J(H)5 gene with multiple somatic mutations. HuMab TONO-1 Vlambda belongs to the lambda light chain variable subgroup I family and is derived from the Vlambdalc germ line gene Humlv1042, and germ line gene Jlambda1 without somatic mutations. The results reveal that the production of HuMab TONO-1, with cytotoxic potential for human T-leukemia/lymphoma cells, is achieved by rearrangement of the V(H)71-4/Humlv1042 germ line variable region gene combination, that is associated with the autoimmune repertoire.

Amino Acid Sequence↗