Biomedical subjects

E Suzuki

Publications and source records attributed to E Suzuki.

At least 19 recordsLinked to original sources

PubMed1999

The role of Pseudomonas aeruginosa elastase as a potent inflammatory factor in a rat air pouch inflammation model.

Pseudomonas aeruginosa, an opportunistic pathogen, can cause life threatening infections in patients compromised by underlying respiratory disease like bronchiectasis, cystic fibrosis and diffuse panbronchiolitis. Most strains of P. aeruginosa produce some kind of protease with broad substrate specificities during the infectious state in the host. P. aeruginosa elastase, one of the strongest exotoxins, has a tissue-damaging proteolytic activity and is capable of degrading such plasma proteins as immunoglobulins, complement factor and cytokines. The present study focused on the effect of P. aeruginosa elastase and was designed to evaluate the neutrophil accumulation at the inflammation site mediated by P. aeruginosa elastase in the inflammatory response in the host. An air pouch model in rats, considered as a useful model of inflammation, was used to analyze the number of leukocytes, the volume of exudate and the concentration of interleukin-8 after the injection of P. aeruginosa elastase into the pouch cavity. The number of neutrophils and the volume of exudate in the pouch cavity increased significantly at 4 h, peaked at 8 h in a dose-dependent manner and then decreased at 24 h. The concentration of interleukin-8 in pouch fluid peaked 4 h earlier than the peak of the neutrophil number. The enzymatic activity of P. aeruginosa elastase seemed to reinforce the inflammation process. The influence of lipopolysaccharide contamination was negligible. Although these observations were made in the subcutaneous cavity, they indicate that P. aeruginosa elastase plays a role as an immunoprovocative factor in the inflammatory response in cases of infection with P. aeruginosa.

Air↗

PubMed1999

Characterization of sphingolipids from mycopathogens: factors correlating with expression of 2-hydroxy fatty acyl (E)-Delta 3-unsaturation in cerebrosides of Paracoccidioides brasiliensis and Aspergillus fumigatus.

Significant differences exist between mammals and fungi with respect to glycosphingolipid (GSL) structure and biosynthesis. Thus, these compounds, as well as the cellular machinery regulating their expression, have considerable potential as targets for the diagnosis and treatment of fungal diseases. In this study, the major neutral GSL components extracted from both yeast and mycelium forms of the thermally dimorphic mycopathogen Paracoccidioides brasiliensis were purified and characterized by 1H and 13C NMR spectroscopy, ESI-MS and ESI-MS/CID-MS, and GC-MS. The major GSLs of both forms were identified as beta-glucopyranosylceramides (GlcCer) having (4E, 8E)-9-methyl-4,8-sphingadienine as long chain base in combination with either N-2'-hydroxyoctadecanoate or N-2'-hydroxy-(E)-3'-octadecenoate. The mycelium form GlcCer had both fatty acids in a approximately 1:1 ratio, while that of the yeast form had on average only approximately 15% of the (E)-Delta 3-unsaturated fatty acid. Cerebrosides from two strains of Aspergillus fumigatus (237 and ATCC 9197) expressing both GalCer and GlcCer were also purified and characterized by similar methods. The GalCer fractions were found to have approximately 70% and approximately 90% N-2'-hydroxy-(E)-3'-octadecenoate, respectively, in the two strains. In contrast, the GlcCer fractions had N-2'-hydroxy-(E)-3'-octadecenoate at only approximately 20 and approximately 50%, respectively. The remainder in all cases was the saturated 2-OH fatty acid, which has not been previously reported in cerebrosides from A. fumigatus. The availability of detailed structures of both glycosylinositol phosphorylceramides [Levery, S. B., Toledo, M. S., Straus, A. H., and Takahashi, H. K. (1998) Biochemistry 37, 8764-8775] and cerebrosides from P. brasiliensis revealed parallel quantitative differences in expression between yeast and mycelium forms, as well as a striking general partitioning of ceramide structure between the two classes of GSLs. These results are discussed with respect to possible functional roles for fungal sphingolipids, particularly as they relate to the morphological transitions exhibited by P. brasiliensis.

Acylation↗

PubMed1999

Crystal structure determinations of oxidized and reduced plastocyanin from the cyanobacterium Synechococcus sp. PCC 7942.

The crystal structures of oxidized and reduced plastocyanins from Synechococcus sp. PCC 7942 have been determined at 1.9 and 1.8 A resolution, respectively, at pH 5.0. The protein consists of only 91 amino acid residues, the smallest number known for a plastocyanin, and apparently lacks the mostly conserved acidic patch that is believed to be important for recognition with electron-transfer partners. The protein has two acidic residues, Glu42 and Glu85, around Tyr83, which is thought to be a possible conduit for electrons, but these are neutralized by Arg88 and Lys58. Residue Arg88 interacts with Tyr83 through a pi-pi interaction in which the guanidinium group of the former completely overlaps the aromatic ring of the tyrosine. Reduction of the protein at pH 5.0 causes a lengthening of one Cu-N(His) bond by 0.36 A, despite the small rms deviation of 0.08 A calculated for the backbone atoms. Moreover, significant conformational changes of Arg88 and Lys58, along with the movement of a water molecule adjacent to the OH group of Tyr83, were observed on reduction; the guanidinium group of Arg88 rotates by more than 11 degrees, and the water molecule moves by 0.42 A. The changes around the copper site and the alterations around Tyr83 may be linked to the reduction of the copper.

Amino Acid Sequence↗

PubMed1999

Molecular mechanisms of endothelin-1-induced cell-cycle progression: involvement of extracellular signal-regulated kinase, protein kinase C, and phosphatidylinositol 3-kinase at distinct points.

Although it is well established that endothelin-1 (ET-1) has not only vasoconstrictive effects but also mitogenic effects, which seem to be implicated in vascular remodeling, little is known about the molecular mechanisms by which ET-1 induces cell-cycle progression. In this study, we examined the effects of ET-1 on the cell-cycle regulatory machinery, including cyclins, cyclin-dependent kinase (cdk), and cdk inhibitors in NIH3T3 cells. ET-1 increased cyclin D1 protein (5.1+/-1.9-fold increase, 8 hours after stimulation, P<0.05), cdk4 kinase activity (2.8+/-0. 5-fold increase, 12 hours after stimulation, P<0.01), and cdk2 kinase activity (2.1+/-0.4-fold increase, 16 hours after stimulation, P<0.05) in a time- and dose-dependent manner. ET-1-induced increase in cyclin D1 protein, and cdk4 kinase activity was not significantly inhibited by an inhibitor of the mitogen-activated protein kinase kinase 1/2, PD98059, nor by the protein kinase C inhibitor calphostin C, whereas ET-1-induced upregulation of cyclin D1 protein and cdk4 kinase activity was significantly inhibited by the phosphatidylinositol 3-kinase inhibitor LY294002. In contrast, ET-1-induced activation of cdk2 kinase was significantly inhibited by PD98059, calphostin C, and LY294002. ET-1 increased 3H-thymidine uptake in a time-dependent fashion (0 hours, 4216+/-264 cpm per well; 8 hours, 5025+/-197 cpm per well; 16 hours, 9239+/-79 cpm per well, P<0.001 versus 0 hours). ET-1-induced increase in 3H-thymidine uptake was significantly inhibited by PD98059, calphostin C, and LY294002. These results suggest that ET-1-induced cell-cycle progression is, at least in part, mediated by the extracellular signal-regulated kinase, protein kinase C, and phosphatidylinositol 3-kinase and that those pathways may be involved in the progression of the cell cycle at distinct points.

3T3 Cells↗

PubMed1999

Successful adoptive immunotherapy of murine poorly immunogenic tumor with specific effector cells generated from gene-modified tumor-primed lymph node cells.

We previously reported that cytokine gene transfer into weakly immunogenic tumor cells could enhance the generation of precursor cells of tumor-reactive T cells and subsequently augment antitumor efficacy of adoptive immunotherapy. We investigated whether such potent antitumor effector T cells could be generated from mice bearing poorly immunogenic tumors. In contrast to similarly modified weakly immunogenic tumors, MCA102 cells, which are chemically induced poorly immunogenic fibrosarcoma cells transfected with cDNA for IL-2, IL-4, IL-6, IFN-gamma, failed to augment the host immune reaction. Because priming of antitumor effector T cells in vivo requires two important signals provided by tumor-associated Ags and costimulatory molecules, these tumor cells were cotransfected with a B7-1 cDNA. Transfection of both IFN-gamma and B7-1 (MCA102/B7-1/IFN-gamma) resulted in regression of s.c. tumors, while tumor transfected with other combinations of cytokine and B7-1 showed progressive growth. Cotransfection of IFN-gamma and B7-1 into other poorly immunogenic tumor B16 and LLC cells also resulted in the regression of s.c. tumors. Cells derived from lymph nodes draining MCA102/B7-1/IFN-gamma tumors showed potent antitumor efficacy, eradicating established pulmonary metastases, but this effect was not seen with parental tumors. This mechanism of enhanced antitumor efficacy was further investigated, and T cells with down-regulated L-selectin expression, which constituted all the in vivo antitumor reactivity, were significantly increased in lymph nodes draining MCA102/B7-1/IFN-gamma tumors. These T cells developed into potent antitumor effector cells after in vitro activation with anti-CD3/IL-2. The strategy presented here may provide a basis for developing potent immunotherapy for human cancers.

Animals↗

PubMed1999

Effects of hypertension, diabetes mellitus, and hypercholesterolemia on endothelin type B receptor-mediated nitric oxide release from rat kidney.

BACKGROUND: Although endothelin-1 is a potent vasoconstrictor peptide, stimulation of endothelin type B receptor (ETBR) causes bidirectional changes in vascular tone, ie, vasodilation and vasoconstriction. Roles of ETBR in pathological conditions are largely unknown. METHODS AND RESULTS: We studied the effect of BQ-3020, a highly selective ETBR agonist, on renal vascular resistance and nitric oxide (NO) release in the isolated, perfused kidney of rats with hypertension, diabetes mellitus, and hypercholesterolemia. Immunohistochemistry of endothelial NO synthase and ETBR was also examined. Infusion of BQ-3020 at concentrations of </=10(-10) mol/L reduced renal perfusion pressure in Dahl salt-resistant (R) rats but increased renal perfusion pressure in Dahl salt-sensitive (S) rats (10(-10) mol/L: -10.3+/-0. 6% versus 11.2+/-1.5%, R versus S; P<0.01). BQ-3020 caused a dose-dependent release of NO in both R and S rats, although the level of NO release in S rats was lower, as detected by chemiluminescence (10(-10) mol/L: 10.7+/-0.7 versus 3.1+/-0.4 fmol/min per gram of kidney, R versus S; P<0.01). Similar effects of BQ-3020 were observed in streptozotocin-induced diabetic rats and diet-induced hypercholesterolemic rats. Expression of endothelial NO synthase decreased in S rats but not in diabetic or hypercholesterolemic rats. In contrast, expression of ETBR in the endothelium was decreased in all 3 disease models compared with that in the vascular smooth muscle cell. CONCLUSIONS: These results suggest that impaired NO release in response to stimulation of ETBR is due, at least in part, to a decrease in endothelial ETBR and may play a role in vascular dysfunction usually associated with arteriosclerosis-related diseases.

Animals↗

PubMed1999

Cloning, sequencing, and transcriptional studies of the gene encoding copper-containing nitrite reductase from Alcaligenes xylosoxidans NCIMB 11015.

Gene encoding of the blue copper-containing nitrite reductase (nir) from Alcaligenes xylosoxidans NCIMB 11015 has been cloned and characterized. The nir is translated into a polypeptide of 360 amino acid residues as a precursor, and the N-terminal 24 residues are subsequently removed upon transport into the periplasm as a mature protein. A specific transcription product of nir was detected only in the presence of nitrate. The aeration level of the culture medium did not show a significant effect on the transcriptional level. A varsigma54 binding sequence is identified upstream of the transcriptional initiation at 53 to 26 nucleotides. A putative fnr box has also been identified in the sequence of the upstream region. The mature polypeptide showed 70% sequence identity with those of the Achromobacter cycloclastes enzyme. The transcriptional start point has been determined at 92 nucleotides upstream of the initiation codon and is preceded by the binding sites for varsigma54 and the fnr box. These results suggest that gene expression depends on the presence of nitrate and is stimulated under an anaerobic environment.

5' Untranslated Regions↗

PubMed1999

Neural expression of hikaru genki protein during embryonic and larval development of Drosophila melanogaster.

Hikaru genki (HIG) is a putative secreted protein of Drosophila that belongs to immunoglobulin and complement-binding protein superfamilies. Previous studies reported that, during pupal and adult stages, HIG protein is synthesized in subsets of neurons and appears to be secreted to the synaptic clefts of neuron-neuron synapses in the central nervous system (CNS). Here we report the analyses of distribution patterns of HIG protein at embryonic and larval stages. In embryos, HIG was mainly observed in subsets of neurons of the CNS that include pCC interneurons and RP5 motorneurons. At third instar larval stage, this protein was detected in a limited number of cells in the brain and ventral nerve cord. Among them are the motorneurons that extend their axons to make neuromuscular junctions on body wall muscle 8. Immunoelectron microscopy showed that these axonal processes as well as the neuromuscular terminals contain numerous vesicles with HIG staining, suggesting that HIG is in a pathway of secretion at this stage. Some neurosecretory cells were also found to express this protein. These data suggest that HIG functions in the nervous system through most developmental stages and may serve as a secreted signalling molecule to modulate the property of synapses or the physiology of the postsynaptic cells.

Animals↗

PubMed1999

Enzyme immunoassay for the measurement of 17alpha-estradiol 17-N-acetylglucosaminide in rabbit urine.

17alpha-estradiol 17-N-acetylglucosaminide (17alphaE2 17NAG) is an estrogen metabolite hitherto obtained only in rabbits. To gain insight into this unique conjugate, an enzyme immunoassay (EIA) was established by using antiserum elicited against 3-[3-(1-carboxypropyl)] ether of 17alphaE2 17NAG-bovine serum albumin conjugate; horseradish peroxidase, as a label; and 3,3',5,5'-tetramethylbenzidine, as a chromogen. The method proved to be specific, and the detection range of the assay was 0.20-10.00 ng/ml. A proposed double conjugate, 3-glucuronide of 17alphaE2 17NAG, was synthesized to validate the EIA. The EIA was applied to the determination of the urinary level of 17alphaE2 17NAG in male and female (pregnant and non-pregnant) rabbits with and without beta-glucuronidase-sulfatase preparation from Helix pomatia. The results showed that 17alphaE2 17NAG was mainly excreted as a double conjugate (17alphaE2 17NAG 3-glucuronide and/or 3-sulfate) and that its level varies during pregnancy.

Acetylglucosamine↗

PubMed1999

Preparation of specific antisera to 15alpha-hydroxyestrogen 15-N-acetylglucosaminides.

3-(1-Carboxypropyl) ether derivatives of 15alpha-hydroxyestradiol 15-N-acetylglucosaminide (15alpha-OHE2 15NAG) and 15alpha-hydroxyestriol (E4) 15NAG were synthesized and conjugated with bovine serum albumin. Antisera elicited in rabbits possessed high affinity and specificity for the 15alpha-hydroxyestrogen (15alpha-OHEs) 15NAG, exhibiting no significant cross-reactivity with 15alpha-OHEs and their positional isomers such as 16NAG and 17NAG. Enzyme immunoassay methods developed by using the purified antisera and horseradish peroxidase-labeled antigens were applied to the measurement of 15alpha-OHEs 15NAG and E4 15NAG in normal pregnancy urine. We demonstrated for the first time that the conjugation of N-acetylglucosamine to E4 occurs at the C-15alpha position.

Animals↗

PubMed1999

Regulation of ventilation before and after sleep in patients with obstructive sleep apnoea.

The objective was to examine whether abnormal breathing during sleep may affect regulation of ventilation after awakening in patients with obstructive sleep apnoea (OSAS). In 19 patients with OSA and 12 normal subjects we examined ventilatory responses to hypoxia (HVR) and to hypercapnia (HCVR) before and after sleep (BS and AS), and compared the changes in ventilatory responses with respiratory events during sleep. In the OSA group, the values of resting ventilation were significantly smaller in AS than those in BS and end-tidal partial pressure of CO2 in arterial blood (Pco2) (PETCO2) rose significantly from BS to AS. The slopes of the HVR or HCVR did not differ between BS and AS. However, both the response lines shifted downward and minute ventilation (VE)80 (VE at arterial oxygen saturation (Sao2) of 80%) in HVR and VE60 (VE at PETCO2 of 60 mmHg) in HCVR decreased significantly from BS to AS. The percentage changes of VE80 and VE60 were significantly correlated with mean Sao2, total sleep time below Sao2 of 90% and lowest Sao2 during sleep. However, in normal subjects we observed no circadian variation in their ventilatory responses. These data support the hypothesis that repeated episodes of nocturnal hypoxia and hypercapnia may modify the regulation of ventilation after awakening in patients with OSA.

Adult↗

PubMed1999

Hypoxia-induced adrenomedullin production in the kidney.

BACKGROUND: Adrenomedullin (AM) is a newly discovered peptide that has a potent vasorelaxant activity. To investigate its potential roles in hypoxia-induced renal injury, we examined whether AM production in the kidney increased under hypoxic conditions. METHODS: The AM transcript levels in Madin-Darby canine kidney (MDCK) cells, rat vascular smooth muscle cells (VSMCs), and rat mesangial cells were assessed by Northern blot analyses under normoxic and hypoxic conditions. The AM peptide in culture media was measured by radioimmunoassay. The effects of hypoxia on accumulation of cAMP in VSMCs were also examined. The stability of AM transcripts under normoxic and hypoxic conditions was compared in the presence of actinomycin D. The effects of hypoxia on AM promoter activity was assessed by transient transfection assays using the AM promoter subcloned upstream of luciferase gene. RESULTS: The expression of AM transcripts increased significantly in MDCK cells, rat VSMCs, and rat mesangial cells under hypoxic conditions without changes in the stability of AM transcripts; however, the AM promoter activity under hypoxic was not elevated significantly. The accumulation of AM peptide in culture media also increased significantly under hypoxic conditions in MDCK cells (2.2 +/- 0.1 fmol/10(5) cells in normoxia vs. 3.5 +/- 0.3 fmol/10(5) cells in hypoxia, 6 hr after hypoxia induction, P < 0.001), and in rat VSMCs (5.5 +/- 0.3 fmol/10(5) cells in normoxia vs. 7.8 +/- 0.4 fmol/10(5) cells in hypoxia, 8 hr after hypoxia induction, P < 0.01). Under hypoxic conditions, cAMP levels in rat VSMCs increased significantly compared with those under normoxic conditions (13.3 +/- 1.4 pmol/well vs. 4.6 +/- 0.4 pmol/well, P < 0.01). CONCLUSIONS: Renal parenchymal cells as well as renal vessels may produce AM under hypoxic conditions.

Adrenomedullin↗

PubMed1999

Crystallization and preliminary X-ray analysis of plastocyanin from cyanobacterium Synechococcus sp. PCC 7942.

A plastocyanin from the cyanobacterium Synechococcus sp. PCC 7942 has been crystallized in two different forms by hanging-drop vapour diffusion with ammonium sulfate as precipitant. Form I is hexagonal, space group P61 or P65, with unit-cell dimensions a = b = 34.62 and c = 107.22 A. Form II is tetragonal, space group P41 or P43, with unit-cell dimensions a = b = 43.05 and c = 56.94 A. Form I crystals diffract to 2.5 A using graphite-monochromated Cu Kalpha radiation from a Rigaku RU-300 rotating-anode generator operated at 40 kV and 100 mA. Form II crystals diffract to 1.9 A using synchrotron radiation at beamline BL6A of the Photon Factory (KEK). Molecular-replacement calculations using the structure of plastocyanin from Ulva pertusa have been performed.

Crystallization↗

PubMed1999

Effects of vasodilatory beta-adrenoceptor antagonists on endothelium-derived nitric oxide release in rat kidney.

The mechanisms for the vascular actions of vasodilatory beta-blockers remain undetermined. For some kinds of beta-blockers, the involvement of nitric oxide (NO) has been suggested. We studied the effects of vasodilatory beta-blockers on renal perfusion pressure (RPP) and NO release in the rat kidney. Infusion of bopindolol, celiprolol, and nebivolol caused a dose-dependent reduction in RPP and an increase in NO release (RPP: bopindolol 10(-6) mol/L, -23+/-2%; celiprolol 10(-4) mol/L, -27+/-2%; nebivolol 10(-5) mol/L, -35+/-3%; NO: bopindolol 10(-6) mol/L, +33+/-2; celiprolol 10(-4) mol/L, +41+/-2; nebivolol 10(-5) mol/L, +45+/-5 fmol. min-1. g kidney-1, mean+/-SEM). Metergoline (10(-6) mol/L), a 5-hydroxytryptamine (5-HT)1/2 antagonist, or NAN-190 (10(-6) mol/L), a 5-HT1A antagonist, almost completely abolished the vasorelaxation and NO release caused by bopindolol, celiprolol, and nebivolol. However, neither propranolol nor bisoprolol decreased RPP. Celiprolol and nebivolol caused vasodilation in the rat thoracic aorta, and it was markedly reduced by endothelial denudation, Nomega-nitro-L-arginine methyl ester (10(-4) mol/L), or NAN-190 (10(-6) mol/L). In deoxycorticosterone acetate-salt hypertensive rats, 4-week administration of celiprolol (50 mg. kg-1. d-1 IV) restored the responses regarding RPP and NO release to acetylcholine. These results suggest that several beta-blockers exert their vasodilatory action through the 5-HT1A receptor/NO pathway and that treatment with these beta-blockers may protect against endothelial injury in hypertension.

Adrenergic beta-Antagonists↗

PubMed1999

Role of nitric oxide-cGMP pathway in adrenomedullin-induced vasodilation in the rat.

We previously reported that adrenomedullin (AM), a potent vasodilator peptide discovered in pheochromocytoma cells, stimulates nitric oxide (NO) release in the rat kidney. To further investigate whether the NO-cGMP pathway is involved in the mechanisms of AM-induced vasodilation, we examined the effects of E-4021, a cGMP-specific phosphodiesterase inhibitor, on AM-induced vasorelaxation in aortic rings and perfused kidneys isolated from Wistar rats. We also measured NO release from the kidneys using a chemiluminescence assay. AM (10(-10) to 10(-7) mol/L) relaxed the aorta precontracted with phenylephrine in a dose-dependent manner. Denudation of endothelium (E) attenuated the vasodilatory action of AM (10(-7) mol/L AM: intact (E+) -25.7+/-5.2% versus denuded (E-) -7. 8+/-0.6%, P<0.05). On the other hand, pretreatment with 10(-8) mol/L E-4021 augmented AM-induced vasorelaxation in the intact aorta (-49. 0+/-7.9%, P<0.05) but not in the denuded one. E-4021 also enhanced acetylcholine (ACh)-induced vasorelaxation in the rat intact aorta (10(-7) mol/L ACh -36.6+/-8.4% versus 10(-8) mol/L E-4021+10(-7) mol/L ACh -62.7+/-3.1%, P<0.05). In perfused kidneys, AM-induced vasorelaxation was also augmented by preincubation with E-4021 (10(-9) mol/L AM -15.4+/-0.6% versus 10(-8) mol/L E-4021+10(-9) mol/L AM -23.6+/-1.2%, P<0.01). AM significantly increased NO release from rat kidneys (DeltaNO: +11.3+/-0.8 fmol. min-1. g-1 kidney at 10(-9) mol/L AM), which was not affected by E-4021. E-4021 enhanced ACh-induced vasorelaxation (10(-9) mol/L ACh -9.7+/-1.7% versus 10(-8) mol/L E-4021+10(-9) mol/L ACh -18.8+/-2.9%, P<0.01) but did not affect ACh-induced NO release from the kidneys. In the aorta and the kidney, 10(-4) mol/L of NG-nitro-L-arginine methyl ester, an NO synthase inhibitor, and 10(-5) mol/L of methylene blue, a guanylate cyclase inhibitor, reduced the vasodilatory effect of AM. These results suggest that the NO-cGMP pathway is involved in the mechanism of AM-induced vasorelaxation, at least in the rat aorta and kidney.

Adrenomedullin↗

PubMed1999

Construction of an L-isoleucine overproducing strain of Escherichia coli K-12.

The genes for a threonine deaminase that is resistant to feedback inhibition by L-isoleucine and for an active acetohydroxyacid synthase II were introduced by a plasmid into a L-threonine-producing recombinant strain of Escherichia coli K-12. Analysis of culture broth of the strain using 13C nuclear magnetic resonance suggested that alpha, beta-dihydroxy-beta-methylvalerate (DHMV) and alpha-keto-beta-methylvalerate (KMV), the third and the fourth intermediates in the L-isoleucine biosynthetic pathway from L-threonine, respectively, accumulated in the medium in amounts comparable to that of L-isoleucine. The ratio of accumulated L-isoleucine:DHMV:KMV were approximately 2:1:1. The concentration of accumulated L-isoleucine increased by twofold after the additional introduction of the genes for dihyroxyacid dehydratase (DH) and transaminase-B (TA-B), and the intermediates no longer accumulated. The resultant strain TVD5 accumulated 10 g/l of L-isoleucine from 40 g/l of glucose.

Acetolactate Synthase↗

PubMed1999

Hypoglycemia induced by interaction between clarithromycin and disopyramide.

A 59-year-old man receiving hemodialysis was hospitalized due to severe hypoglycemic attack. The patient had been treated with disopyramide (50 mg/day) because of paroxysmal atrial fibrillation. Hypoglycemia occurred after taking clarithromycin (CAM, 600 mg/day), a macrolide antibiotic. The serum disopyramide concentration reached 8.0 micrograms/ml (23.6 microM) in the presence of CAM, while it was 1.5 micrograms/ml before the addition of CAM. A 75 g oral glucose tolerance test and daily profiles of blood glucose value showed that blood glucose levels were significantly lower in the presence of CAM and disopyramide compared to that in the absence of these drugs. The Turner index in the presence of CAM and disopyramide was significantly higher than that in the absence of these drugs, suggesting that a toxic concentration of disopyramide enhanced insulin secretion, resulting in the induction of hypoglycemic attacks, in which the inhibitory effects of CAM on the hepatic chytochrome P-450 might be involved. QT and QTc intervals were prolonged in the presence of CAM and disopyramide, but torsades de points were not observed in this patient receiving nicorandil (15 mg/day). Thus, it should be taken into account that life-threatening hypoglycemia may result from the interaction between clarithromycin and disopyramide.

Anti-Arrhythmia Agents↗

PubMed1999

High-temperature effects on antibody response to viral antigen in mice.

To determine the effects of high-temperature exposure on antibody response to viral antigen in mice, male BALB/c mice were placed for 13 days in animal chambers at 23 degrees C, 32 degrees C, and 35.5 degrees C. Rectal temperature rose from 37 degrees C to 39 degrees C on day 1 in a 35.5 degrees C environment. The rectal temperature was kept constant throughout the exposure period. The IgG-antibody to Sendai virus (SV) antigen was inhibited to about 50% of the control value (23 degrees C). The serum corticosterone concentration indicating thermal stress increased steadily, peaking on day 1 and then gradually decreased and recovered to the normal level on day 13. Body weight decreased to about 72% of the controls on day 13. Thymus and spleen weight decreased to 31.7% and 61.5% respectively. At 32 degrees C, these effects were less than at 35.5 degrees C. Effects of high-temperature exposure at 35.5 degrees C appeared to noticeably decrease thymus and spleen weight. It is clear that IgG-antibody response to SV antigen is suppressed by high-temperature exposure.

Animals↗