Biomedical subjects

K Matsui

Publications and source records attributed to K Matsui.

At least 127 records · Page 7Linked to original sources

PubMed2000

Acute cerebellar hemorrhage in a patient with Klinefelter syndrome: XXY karyotype obtained postmortem from cells from pericardial fluid.

A case of Klinefelter syndrome and a spontaneous cerebellar hemorrhage in a 12-year-old boy is presented. Autopsy revealed that the hemorrhage was due to the rupture of a dilated artery in an arteriovenous malformation in the right cerebellar hemisphere. The small, undescended testes exhibited partial atrophy of the seminiferous tubules. Postmortem chromosome analysis of cells from the pericardial fluid demonstrated a 47, XXY karyotype. He had previous surgical treatment for bilateral thumb polydactyly and patent ductus arteriosus. In juvenile cases of sudden death with overlapping morphological dysgenesis, postmortem karyotyping may provide important diagnostic information.

Cause of Death↗

PubMed2000

Molecular characterization of fatty acid alpha-hydroperoxide-forming enzyme (alpha-oxygenase) in rice plants.

Genes encoding an alpha-oxygenase, in Nicotiana tabacum and Arabidopsis thaliana, have been recently isolated. However, the reaction mechanism of the enzyme has not so far been elucidated. In this study, a cDNA encoding the fatty acid alpha-oxygenase gene in rice plants was isolated. The deduced amino acid sequence showed high similarity (63.6%) to that of N. tabacum. The gene was cloned into an expression vector system, pQE-30, and expressed in Escherichia coli as a host cell. Palmitic acid as a substrate was incubated with the lysate of the cells, and the products were analysed by HPLC. A compound formed predominantly by the recombinant enzyme was shown to be n-pentadecanal. By incubating the mixture at 0 degrees C, 2-hydroperoxypalmitic acid was detected as a primary product and little formation of n-pentadecanal was detected. Furthermore, uptake of molecular oxygen was observed with an oxygen electrode. This indicated that the gene in rice plants encodes the alpha-oxygenase.

Arabidopsis↗

PubMed2000

A lipid-hydrolysing activity involved in hexenal formation.

Short-chain aldehydes such as (3Z)-hexenal and n-hexanal are formed from lipids through sequential actions of lipid-hydrolysing, lipoxygenase and fatty acid hydroperoxide lyase activities. The aldehydes are formed upon wounding of plant tissues, and are reported to have bactericidal and fungicidal activities. Furthermore, it has been reported that the aldehydes can induce expression of a subset of genes involved in disease resistance and that they are involved in a defence response against insect herbivores. Although several genes encoding lipoxygenases and the lyases have been isolated, and characterized to some extent, only little is known about the enzyme accountable for the lipid-hydrolysing step. In this study, we tried to characterize the lipid-hydrolysing activity involved in the short-chain aldehyde formation in Arabidopsis. When Arabidopsis leaves were homogenized, (3Z)-hexenal was formed rapidly within a few minutes. During this time period, the amount of alpha-linolenic acid and C(16:3) rapidly decreased. Such a rapid increase of the aldehyde was repressed almost completely when the leaves were homogenized under a nitrogen stream, and instead free trienoic acids accumulated. A lipase inhibitor, quinacrine, successfully repressed the hydrolysis. It was revealed that trienoic acids in monogalactosyldiacylglycerol were predominantly hydrolysed during the formation of short-chain aldehydes. Collectively, it is suggested that the lipolytic enzyme involved in the short-chain aldehyde formation is a galactolipid-specific lipase.

Arabidopsis↗

PubMed2000

[Polymyositis with marked paravertebral muscle atrophy in patients with primary biliary cirrhosis].

We reported two patients with polymyositis (PM) associated with primary biliary cirrhosis (PBC) who noticed head-drop as the incipient symptom. Muscle computed tomography showed marked hypodensity in the paravertebral muscles as compared with limb muscles. Patient 1, a 48-year-old female, was admitted in our hospital for the examination because of her neck and proximal limb muscle weakness, increasing fatigability, and abnormal serum liver and muscle enzyme levels. She felt her throat was so dry at age 39, and she noticed weight loss at age 41 and head-drop at age 42. A diagnosis of PM was made from symmetrical proximal limb muscle weakness, elevated creatine kinase (CK) level, and the electromyographic and muscle biopsy findings. Her illness was also diagnosed as PBC because of the increased serum alkaline phosphatase and IgM immunoglobulin levels, and liver biopsy findings. The anticentromere antibody titer was positive, though the antimitochondrial antibody titer negative. The HLA typing was DR 4, DR 8, DR53, DQ 4, DQ 6, DRB 1 (0405/0803). She was placed on 60 mg of prednisolone/day for PM and 300 mg of ursodeoxycholic acid/day for PBC. Patient 2, a 49-year-old female, presented with proximal limb muscle weakness and head-drop. Serum CK, alkaline phosphatase and IgM immunoglobulin levels were increased. The antimitochondrial antibody titer was positive. She began to have 60 mg of prednisolone/day, and 50 mg of azatioprine/day and 300 mg of ursodeoxycholic acid/day were subsequently added. PM associated with PBC seems to be rare, because only 21 cases have been described in literature. In those patients, marked paravertebral muscle atrophy has never been described. Further study is necessary to examine whether or not the preferential paravertebral muscle involvement is a striking and diagnostic finding for PM with PBC.

Atrophy↗

PubMed2000

Na+/H+ exchange inhibitor reduces vascular injury caused by ischemia-reperfusion in the rat hind limb.

This study was designed to evaluate the effects of an Na+/H+ exchange inhibitor, SM-20550, on ischemia-reperfusion injury in the skeletal muscle. Male Sprague-Dawley rats were exposed to ischemia and reperfusion by clamping and releasing clamps both at the abdominal aorta and the bilateral femoral arteries. Rats were divided into three groups; the sham, the SM-20550 treated (SM), and the untreated control (Control) groups. In the SM and control groups, rats were exposed to 5-hr ischemia and 5-hr reperfusion. In the sham group, vessel isolation only was performed. SM-20550 (2.8 mg/kg/hr) in the SM group or vehicle in the sham and control group was continuously administered during ischemia and reperfusion periods. The wall thickness of the vessels were significantly (p<0.01) decreased in the control group than any other group. The internal diameter was significantly (p<0.01) higher in the control and SM group than in the sham group. The wall thickness/internal diameter ratio was significantly (p<0.05) lower in the control group than in the SM group. Thus, an Na+/H+ exchange inhibitor, SM-20550, ameliorated the morphological change due to ischemia reperfusion. These findings provide a clue into the mechanism of ischemia reperfusion injury.

Animals↗

PubMed1999

Kupffer cells from Schistosoma mansoni-infected mice participate in the prompt type 2 differentiation of hepatic T cells in response to worm antigens.

Infection with Schistosoma mansoni, a portal vein-residing helminth, is well known to generate life cycle-dependent, systemic immune responses in the host, type 1 deviation during the prepatent period, and type 2 polarization after oviposition. Here we investigated local immunological changes in the liver after infection. Unlike splenocytes, hepatic lymphocytes from infected mice during the prepatent period already produced a higher amount of IL-4 and a lesser amount of IFN-gamma than those from uninfected mice. Hepatic lymphocytes, particularly conventional T cells, but not NK1.1+ T cells, promptly produced IL-4 in response to worm products, soluble worm Ag preparation (SWAP), whenever presented by Kupffer cells from infected mice. The hepatic lymphocytes that had been stimulated with SWAP presented by infected mice-derived Kupffer cells produced a huge amount of IL-4, IL-13, and IL-5 as well as little IFN-gamma in response to immobilized anti-CD3 mAb. Kupffer cells from uninfected mice produced IL-6 and IL-10, but not IL-12 or IL-18, in response to SWAP stimulation and gained the potential to additionally produce IL-4 and IL-13 after the infection. These results suggested that prompt type 2 deviation in the liver after the infection might be due to the alteration of Kupffer cells that induces SWAP-mediated type 2-development of hepatic T cells.

Animals↗

PubMed1999

Inhibitory effects of donepezil hydrochloride (E2020) on cholinesterase activity in brain and peripheral tissues of young and aged rats.

Donepezil hydrochloride (donepezil: E2020: (+/-)-2-[(1-benzylpiperidin-4-yl)methyl]-5,6-dimethoxy-indan-1-one monohydrochloride)) is a centrally acting acetylcholinesterase inhibitor developed for the treatment of Alzheimer's disease. In the present study, its inhibitory effect on the activity of cholinesterase ex vivo was evaluated in the brain, plasma, erythrocytes, heart, small intestine, liver and pectoral muscle of young adult as well as aged rats, in comparison with that of tacrine (9-amino-1,2,3,4-tetrahydroacridine hydrochloride). In aged animals, cholinesterase activity in heart, small intestine and pectoral muscle was lower, whereas that in plasma and liver was higher than in young rats. Both groups showed the highest levels in the brain. Donepezil, at doses of 1.25, 2.5 and 5 mg/kg, p.o., inhibited brain, plasma, erythrocyte, liver and pectoral muscle cholinesterase activity in young rats in a dose-dependent manner but had less effect on cholinesterase activity in heart and small intestine. In aged animals, inhibition of cholinesterase activity in the brain, erythrocytes and pectoral muscle by donepezil was more potent than that in young animals. Tacrine, at doses of 5, 10 and 20 mg/kg, p.o., dose-dependently inhibited cholinesterase activity in all tissues of both young and aged animals, but most potently in heart, small intestine and liver. The inhibition of cholinesterase activity by tacrine in the brain, plasma, erythrocytes, heart and liver was more potent in aged rats than in tissues of young rats. Brain and plasma concentrations of unchanged donepezil and tacrine were measured in the same animals as used for the cholinesterase inhibition study. Brain and plasma concentrations of donepezil and tacrine were higher in aged than in young animals. It is concluded that the inhibitory effects of donepezil and tacrine on cholinesterase activity are greater in aged than in young rats, owing to differences in the tissue concentrations of these compounds between young and aged animals. It is also suggested that the effect of donepezil on cholinesterase activity is more tissue-selective than that of tacrine.

Aging↗

PubMed1999

Effect of donepezil hydrochloride (E2020) on basal concentration of extracellular acetylcholine in the hippocampus of rats.

The effects of oral administration of the centrally acting acetylcholinesterase (AChE) inhibitors, donepezil hydrochloride (donepezil: E2020: (+/-)-2-[(1-benzylpiperidin-4-yl)methyl]-5,6-dimethoxy-indan-1-one monohydrochloride), tacrine (9-amino-1,2,3,4-tetrahydroacridine hydrochloride) and ENA-713 (rivastigmine: (S)-N-ethyl-3-[(1-dimethyl-amino)ethyl]-N-methyl-phenylcarbamate hydrogentartrate), which have been developed for the treatment of Alzheimer's disease, on the extracellular acetylcholine concentration in the hippocampus of rats were evaluated by using a microdialysis technique without adding cholinesterase inhibitor to the perfusion solution. We also compared the inhibition of brain AChE and the brain concentrations of these drugs. Donepezil at 2.5 mg/kg and tacrine at 5 mg/kg showed significant effects for more than 6 h. At these doses, the maximum increases were observed at about 1.5 h after administration of donepezil, and at about 2 h with tacrine, and were 499% and 422% of the pre-level, respectively. ENA-713 produced significant effects at doses of 0.625, 1.25 and 2.5 mg/kg, which lasted for about 1, 2 and 4 h, respectively. The maximum increases produced by these doses at about 0.5 h after administration were 190, 346 and 458% of the pre-level, respectively. The time courses of brain AChE inhibition with donepezil at 2.5 mg/kg, tacrine at 10 mg/kg and ENA-713 at 2.5 mg/kg were mirror images of the extracellular acetylcholine-increasing action at the same doses. The time courses of the brain concentrations of drugs after oral administration of donepezil at 2.5 mg/kg and tacrine at 10 mg/kg were consistent with those of brain AChE inhibition at the same doses, and there was a linear relation between these parameters. Brain concentration of ENA-713 at 2.5 mg/kg was below the limit of quantification at all time points measured. These results suggest that oral administration of donepezil, tacrine and ENA-713 increases acetylcholine concentration in the synaptic cleft of the hippocampus mostly through AChE inhibition, and that donepezil has a more potent activity than tacrine and a longer-lasting effect than ENA-713 on the central cholinergic system.

Acetylcholine↗

PubMed1999

Mutagenicity of 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) in the new gpt delta transgenic mouse.

Gender differences and organ specificity of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced mutagenesis were examined with the new gptdelta transgenic mouse (T. Nohmi, M. Katoh, H. Suzuki, M. Matsui, M. Yamada, M. Watanabe, M. Suzuki, N. Horiya, O. Ueda, T. Shibuya, H. Ikeda, T. Sofuni, A new transgenic mouse mutagenesis test system using Spi-and 6-thioguanine selections (Environ. Mol. Mutagen. 28 (1996) 465-470). In this mouse model, two distinct selections are employed to efficiently detect different types of mutations, i.e 6-thioguanine (6-TG) selection for point mutations and Spi-selection for deletions, respectively. In both selections, the highest mutant frequencies were observed in colon, followed by in spleen and liver. No increases in mutations were observed in testis, brain and bone marrow in PhIP-treated male mice. No significant differences in 6-TG and Spi- mutant frequencies were observed in colon and liver between male and female treated mice. The correlation between PhIP-induced mutagenesis and carcinogenesis in colon is discussed.

Animals↗

PubMed1999

Active role of glutamate uptake in the synaptic transmission from retinal nonspiking neurons.

We examined the role of glutamate uptake in the synaptic transmission of graded responses from newt retinal bipolar cells (BCs) to ganglion layer cells (GLCs). In dissociated Müller cells (retinal glia), glutamate evoked an uptake current that was effectively inhibited by L-trans-pyrrolidine-2,4-dicarboxylic acid (PDC). PDC had no effect on the non-NMDA receptors of dissociated spiking neurons. In the retinal slice preparation, dual whole-cell recordings were performed from a pair of BC and GLC. A depolarizing pulse applied to a BC activated the Ca(2+) current (I(Ca)) in the BC and evoked an EPSC in the GLC. Application of PDC prolonged both non-NMDA and NMDA receptor-mediated components of the evoked EPSC but changed neither the amplitude nor time course of I(Ca). When the slice preparation was superfused with a solution containing glutamate but not PDC, the evoked EPSC decreased in amplitude without changing the time course, suggesting that the prolongation of the evoked EPSC is not attributable to a simple increase in ambient glutamate concentration after inhibition of glutamate uptake. Because PDC did not affect the amplitude, time course, or frequency of spontaneous EPSCs, it is unlikely that PDC modified presynaptic and/or postsynaptic mechanisms. These results indicate that inhibition of glutamate uptake slows the clearance of glutamate accumulated in the synaptic cleft by multiple quantal release and prolongs the evoked EPSC. The role of glutamate uptake at synapses in the inner retina is not only to maintain the extracellular glutamate concentration at a low level but also to terminate the light-evoked EPSCs rapidly.

Animals↗

PubMed1999

A Na+-H+ exchange inhibitor (SM-20550) protects from microvascular deterioration and myocardial injury after reperfusion.

Na+-H+ exchange inhibitors may reduce myocardial damage after reperfusion. However, their effects on microvascular deterioration are not known. We examined the potency of a novel Na+-H+ exchange inhibitor, SM-20550 [ N-(Aminoiminomethyl)-1,4-dimethyl-1H-indole-2-carboxamide methanesulfonate], and its effects on microvascular damage after reperfusion. In an in vitro study, the Na+-H+ exchange inhibiting activity of SM-20550 was about 10 times greater than that of ethylisopropyl amiloride. In in vivo experiments, we occluded the left circumflex coronary artery in 29 dogs for 2 h and then reperfused for 5 h. SM-20550 was administered either before ischemia (n = 11) or before reperfusion (n = 7). Another 11 dogs served as controls. We found that SM-20550 not only improved coronary vasodilator responses to acetylcholine and adenosine after reperfusion, but also reduced infarct size (P < 0.01). Intramyocardial bleeding, which should reflect microvascular damage, was not found in dogs with SM-20550 treatment. Infarct size was correlated inversely with collateral blood flow in control (both, P < 0.01) but not in SM-20550-treated animals. Furthermore, SM-20550 significantly suppressed ventricular fibrillation during both ischemia and reperfusion. These results suggest that protective effects of Na+-H+ exchange inhibitors on reperfused myocardium are due at least in part to microvascular protection.

Acetylcholine↗

PubMed1999

Simultaneous determination of donepezil (aricept) enantiomers in human plasma by liquid chromatography-electrospray tandem mass spectrometry.

A rapid, sensitive and enantioselective LC-MS-MS method using deuterium-labeled internal standard was developed and evaluated for the simultaneous quantitative determination of donepezil enantiomers in human plasma without interconversion during clean-up process and measurement. The use of an avidin column allowed the separation of donepezil enantiomers, which were specifically detected by MS-MS without interference from its metabolites and plasma constituents. Evaluation of this assay method shows that samples can be assayed with acceptable accuracy and precision within the range from 0.0206 ng/ml to 51.6 ng/ml for both R-donepezil and S-donepezil. This analytical method was applied to the simultaneous quantitation of donepezil enantiomers in human plasma.

Calibration↗

PubMed1999

Triglyceride-lowering effect of a novel insulin-sensitizing agent, JTT-501.

JTT-501, 4-[4-[2-(5-methyl-2-phenyl-4-oxazolyl)ethoxy]benzyl]-3, 5-isoxazolidinedione, is a novel insulin-sensitizing agent. We investigated the triglyceride-lowering activity of JTT-501 in a high-fat (HF) rat model. The HF rats showed insulin resistance with elevation of fasting insulin levels and reduction of insulin-stimulated glucose oxidation. There was also a tendency towards increased basal insulin and triglyceride levels. Oral administration of JTT-501 (3-30 mg kg(-1) day(-1) for 7 days) reduced basal triglyceride levels dose dependently with a minimum effective dose of 3 mg kg(-1) day(-1). Furthermore, regarding triglyceride metabolism, JTT-501 (30 mg kg(-1) day(-1) for 15 days, p.o.) decreased hepatic triglyceride output rate and serum triglyceride half-life (T1/2). In contrast, pioglitazone (30 mg kg(-1) day(-1) for 15 days, p.o.) reduced T1/2, but did not affect hepatic triglyceride output rate. We conclude that JTT-501 possesses potent triglyceride-lowering activity due to its inhibition of triglyceride secretion from the liver and enhancement of triglyceride disposal in peripheral tissues.

Animals↗

PubMed1999

New O-acetyltransferase-deficient Ames Salmonella strains generated by specific gene disruption.

CoASAc-dependent N-hydroxyarylamine O-acetyltransferase (OAT) is an enzyme involved in the intracellular metabolic activation of N-hydroxyarylamines derived from mutagenic nitroarenes and aromatic amines. The oat gene encoding the enzyme of S. typhimurium TA98 and TA100 was specifically disrupted and the sensitivities of the resulting strains, i.e., YG7130 and YG7126, to mutagens were compared with those of the conventional oat-deficient strains, i.e., TA98/1,8DNP6 and TA100/1,8DNP, respectively. The new oat-deficient strains and the conventional strains exhibited similar sensitivity against most of the chemicals tested: both strains YG7130 and strain TA98/1,8-DNP6 were resistant to mutagenicity by 1,8-dinitropyrene (1, 8-DNP), 1-nitropyrene, 2-amino-6-methyldipyrido[1,2-alpha:3', 2'-d]imidazole (Glu-P-1) and 2-amino-3-methyl-3H-imidazo[4, 5-f]quinoline (IQ); neither strain YG7130 nor strain TA98/1,8-DNP6 was resistant to the mutagenicity of 3-amino-1-methyl-5H-pyrido[4, 3-b]indole (Trp-P-2); strain YG7126 and strain TA100/1,8-DNP were refractory to the mutagenicity of 1,8-DNP. However, the order of the sensitivity against 2-nitrofluorene (2-NF) was TA98>YG7130>TA98/1, 8-DNP6 and TA100>YG7126>TA100/1,8-DNP. Since the strains YG7130 and YG7126 have chloramphenicol resistance (Cmr) gene in place of the chromosomal oat gene for gene disruption, the possible involvement of chloramphenicol acetyltransferase (CAT) encoded by the Cmr gene in the activation of 2-NF was examined. Strikingly, introduction of plasmid pACYC184 carrying the Cmr gene alone substantially enhanced the sensitivity of the conventional oat-deficient strains to 2-NF. These results suggest that the new strains as well as the conventional strains are useful to assess the roles of OAT in the metabolic activation of nitroaromatics and aromatic amines in S. typhimurium, and also that CAT has the ability to activate N-hydroxy aromatic amines to mutagens.

Acetyltransferases↗

PubMed1999

IL-18 up-regulates perforin-mediated NK activity without increasing perforin messenger RNA expression by binding to constitutively expressed IL-18 receptor.

IL-18 is a powerful inducer of IFN-gamma production, particularly in collaboration with IL-12. IL-18, like IL-12, also augments NK activity. Here we investigated the molecular mechanism underlying the up-regulation of killing activity of NK cells by IL-18. IL-18, like IL-12, dose dependently enhanced NK activity of splenocytes. This action was further enhanced by costimulation with IL-12. Treatment with anti-IL-2R Ab did not affect IL-18- and/or IL-12-augmented NK activity, and splenocytes from IFN-gamma-deficient mice showed enhanced NK activity following stimulation with IL-12 and/or IL-18. Splenocytes from the mice deficient in both IL-12 and IL-18 normally responded to IL-18 and/or IL-12 with facilitated NK activity, suggesting that functional NK cells develop in the absence of IL-12 and IL-18. IL-18R, as well as IL-12R mRNA, was constitutively expressed in splenocytes from SCID mice, which lack T cells and B cells but have intact NK cells, and in those from IL-12 and IL-18 double knockout mice. NK cells isolated from SCID splenocytes expressed IL-18R on their surface. IL-18, in contrast to IL-12, did not enhance mRNA expression of perforin, a key molecule for exocytosis-mediated cytotoxicity. However, pretreatment with concanamycin A completely inhibited this IL-18- and/or IL-12-augmented NK activity. Furthermore, IL-18, like IL-12, failed to enhance NK activity of splenocytes from perforin-deficient mice. These data suggested that NK cells develop and express IL-12R and IL-18R in the absence of IL-12 or IL-18, and that both IL-18 and IL-12 directly and independently augment perforin-mediated cytotoxic activity of NK cells.

Animals↗

PubMed1999

Pharmacological profiles of a novel oral antidiabetic agent, JTT-501, an isoxazolidinedione derivative.

JTT-501, 4-[4-[2-(5-methyl-2-phenyl-4-oxazolyl)ethoxy]benzyl]-3,5-isoxaz olidinedione, is an isoxazolidinedione derivative which is structurally distinct from thiazolidinediones such as pioglitazone and troglitazone. We investigated the effects of JTT-501 on insulin-sensitizing activity and in rodent diabetic models. JTT-501 enhanced insulin-stimulated cell differentiation of 3T3-L1 fibroblasts with an EC50 value of 110 nM. Furthermore, JTT-501 activated peroxisome proliferator-activated (PPA) gamma and alpha receptors with the EC5-fold values of 0.28 and 5.4 microM, respectively. In the non-insulin-dependent diabetes mellitus model KK-Ay mice, JTT-501 improved hyperglycemia, hyperinsulinemia and hypertriglyceridemia, and enhanced insulin-stimulated glucose oxidation in adipose tissues. JTT-501 was also effective in the non-insulin-dependent diabetes mellitus model Zucker diabetic fatty (ZDF) rats but not in the insulin-dependent diabetes mellitus model streptozotocin-induced diabetic mice. These observations suggest that JTT-501 enhances insulin sensitivity in peripheral tissues and improves hyperglycemia, hyperinsulinemia, and hypertriglyceridemia in non-insulin dependent diabetes mellitus models. In particular, the triglyceride-lowering activity of JTT-501 is a unique characteristic compared to the thiazolidinediones. Therefore, JTT-501 may be a promising antidiabetic agent for treating non-insulin-dependent diabetes mellitus patients with insulin resistance.

3T3 Cells↗

PubMed1999

Quantitative determination of E5880 in rat plasma by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.

A simple and sensitive method is described for the determination of E5880 in rat plasma. The method is based on high-performance liquid chromatography/electrospray ionization mass spectrometry, using deuterated E5880 as an internal standard. Selected reaction monitoring is employed for selectivity and sensitivity, this in turn enables quantification in a short period of time (within 7 minutes) over the extended range of 0.1-1000 ng/ml with acceptable precision and accuracy. The method demonstrated to be suitable for the quantitative analysis of E5880 in rat plasma. The pharmacokinetic profile of E5880 after a single intravenous administration of E5880 was elucidated.

Animals↗

PubMed1999

Spi(-) selection: An efficient method to detect gamma-ray-induced deletions in transgenic mice.

Despite the importance of genome rearrangement in the etiology of cancer and human genetic disease, deletion mutations are poorly detectable by transgenic rodent mutagenicity tests. To facilitate the detection and molecular analysis of deletion mutations in vivo, we established a transgenic mouse model harboring a lambdaEG10 shuttle vector that includes the red and gam genes for Spi(-) (sensitive to P2 interference) selection [Nohmi et al. (1996] Environ. Mol. Mutagen. 28:465-470]. This selection has a great advantage over other genetic systems, because phage deletion mutants can be preferentially selected as Spi(-) plaques, which can then be subjected to molecular analysis. Here, we show nucleotide sequences of 41 junctions of deletion mutations induced by gamma-irradiation. Unlike spontaneous deletion mutants, more than half of the large deletions occurred between short homologous sequences from one to eight bp. The remaining junctions had no such homologous sequences. Intriguingly, two Spi(-) mutants had P (palindrome)-like nucleotide additions at the breakpoints, which are frequently observed in the coding junctions of V(D)J recombination, suggesting that broken DNA molecules with hairpin structures can be intermediates in the repair of radiation-induced double-strand breaks. We conclude that Spi(-) selection is useful for the efficient detection of deletion mutations in vivo and that most rearrangements induced by gamma-rays in mice are mediated by illegitimate recombination through DNA end-joining.

Animals↗