Biomedical subjects

K Matsui

Publications and source records attributed to K Matsui.

At least 253 records · Page 14Linked to original sources

PubMed1996

Effect of aluminum ion on Fe(2+)-induced lipid peroxidation in phospholipid liposomes under acidic conditions.

The effects of Al3+ on Fe(2+)-induced lipid peroxidation in phospholipid liposomes consisting of phosphatidylcholine (PC) and phosphatidylserine (PS) were examined under acidic conditions. The stimulatory effect of Al3+ on Fe(2+)-induced lipid peroxidation in the liposomes showed a biphasic response against pH variation, and the maximum stimulation was observed around pH 6.0. In addition, it was found that the stimulatory effect of Al3+ on the lipid peroxidation was dependent on the proportion of PS in the liposomes. On the other hand, the lipid peroxidation in PC liposomes was not stimulated by the addition of Al3+. From these findings, it is suggested that the Al3+ effect on Fe(2+)-induced lipid peroxidation under acidic conditions is largely dependent on the phospholipid composition. Trivalent cations such as Tb3+ and Ga3+ also stimulated Fe(2+)-induced lipid peroxidation in PC/PS liposomes under acidic conditions, but divalent cations (Zn2+ and Mn2+) showed no stimulatory effect. The extents of Fe2+ disappearance and Fe3+ formation during the reaction were enhanced by the addition of Al3+ or Ga2+, but Tb3+ had no effect on Fe2+ disappearance. The results with 1,6-diphenyl-1,3,5-hexatriene (DPH) showed that the fluorescence anisotropy of DPH-labeled PC/PS liposomes under acidic conditions was increased by the addition of Al3+. Furthermore, there is a relation between the extents of the fluorescence anisotropy of the complex and TBARS production. In contrast, the fluorescence anisotropy of DPH molecules embedded in PC liposomes was not changed by the addition of Al3+. Based on these results, a possible mechanism of the stimulatory effect of Al3+ on Fe(2+)-induced lipid peroxidation under acidic conditions is discussed.

Aluminum↗

PubMed1996

Dose-escalation study of oral etoposide and carboplatin in patients with advanced lung cancer.

A dose-escalation study of daily etoposide and carboplatin was carried out on 23 patients with advanced lung cancer using a starting dose of 40 mg/m2/day etoposide given orally for 21 days and 250 mg/m2 carboplatin given intravenously (IV) on day 1. A total of 41 courses were given. Myelosuppression was the major dose-limiting toxicity. The maximum tolerated dose was reached at the fourth level with 40 mg/m2/day etoposide for 21 days and 400 mg/m2 carboplatin on day 1, once every 4 weeks. Non-hematological toxicities were generally mild or reversible. The recommended doses of this combination chemotherapy are 40 mg/m2/day etoposide for 21 days and 350 mg/m2 carboplatin on day 1. The response rate for non-small cell lung cancer and small cell lung cancer was 16.7% and 60% (95% confidence intervals of 3.6% to 41.4%, and 14.7% to 94.7%), respectively. A phase II study is necessary to define the efficacy and safety of this combination chemotherapy.

Administration, Oral↗

PubMed1996

Comparative studies of thrombolysis with single-chain and two-chain recombinant tissue-type plasminogen activators in canine coronary thrombosis.

Tissue-type plasminogen activator (t-PA) can occur in two different forms, single- and two-chain t-PA. Such a difference in structure of the t-PA molecule may induce different biological functions. We compared the thrombolytic efficacy of single-chain t-PA with that of two-chain t-PA and urokinase in a canine thrombosis model. The thrombolytic properties of single- and two-chain recombinant t-PA and urokinase with equivalent activity in vitro after intravenous infusion were examined in 24 anesthetized, open-chest dogs with intracoronary thrombi. Repeated coronary angiography showed that the time to reperfusion was 29.0 +/- 4.8, 32.5 +/- 6.3, and 39.2 +/- 6.8 min, respectively. One dog in the single-chain t-PA group and all dogs in the vehicle group showed no recanalization. Plasma t-PA antigen reached similar plateau levels within 15. min in both the single- and two-chain t-PA groups. The infusion of single- and two-chain t-PA was not associated with systemic fibrinolytic activation, except for a decrease in alpha 2-plasmin inhibitor in single-chain t-PA. However, the infusion of urokinase was associated with significant depletion of fibrinogen. These findings suggest that single-chain t-PA has potent thrombolytic effect without systemic fibrinolytic activity similar to that of two-chain t-PA in a canine coronary artery thrombosis model.

Animals↗

PubMed1996

Purified protein from Salmonella typhimurium inhibits the interleukin-2 response of murine splenic T-lymphocytes activated with anti-CD3 antibody.

Previously, we demonstrated that the immunosuppression induced by a purified preparation of Salmonella typhimurium-derived inhibitor of T-cell proliferation (STI) can be observed in terms of suppression of the proliferation of murine spleen cells stimulated with a mitogenic lectin. In the present study, I observed that STI inhibited the interleukin-2 (IL-2) response of purified murine splenic T lymphocytes stimulated with anti-CD3 antibody. The flow cytometric analysis of IL-2 receptor (IL-2R) expression on T cells showed that STI specifically suppressed the expression of IL-2R beta and IL-2R gamma. Furthermore, when the IL-2-dependent T-cell line CTLL-2 was incubated with STI, the growth of CTLL-2 cells was significantly inhibited. These results suggest that the target cells for STI are T cells themselves, and that the suppression of T-cell proliferation induced by STI might involve a defect in the IL-2 receptor (IL-2R) function of T cells.

Animals↗

PubMed1996

Determinants of myelosuppression in the treatment of non-small cell lung cancer with cisplatin-containing chemotherapy.

Data on 16 potential risk factors for myelosuppression were assessed in 134 patients who received either vindesine and cisplatin (VP) or mitomycin C, vindesine and cisplatin (MVP) for inoperable stage III or IV non-small cell lung cancer in a randomized trial. Determinant factors for myelosuppression were evaluated by using univariate analysis and the logistic regression model. Recursive partitioning and amalgamation (RPA) was also used to define patient subgroups frequently suffering from severe bone marrow toxicity. Overall, 33 (25%) of 134 patients experienced at least one episode of grade 4 leukopenia. In univariate analysis, age, body surface area, serum creatinine, and pretreatment hemoglobin concentration were associated with severe leukopenia. A multivariate analysis using the logistic regression method showed that only raised creatinine level was an independent predictor for grade 4 leukopenia (P = 0.049). The RPA model generated three distinct subgroups based on age, body surface area and regimen. The three subgroups were distinguished by the frequency of severe (grade 4) leukopenia (50%, 25%, and 2.4%, respectively) (P < 0.001). Grade 4 leukopenia occurred more frequently in patients in class 3 (age > or = 65 years and treatment with MVP). The RPA model was useful in identifying the risk factors for myelosuppression induced by cisplatin-based chemotherapy, and in defining patient subgroups with elevated risk of toxicity.

Adult↗

PubMed1996

Effectiveness and limitations of the fallback I algorithm for transient supraventricular tachyarrhythmias in DDD pacing.

To examine the function of the fallback I algorithm (Chorus I, Ela Medical Inc., Montrouge, France), which automatically changes the DDD mode to VDI during transient supraventricular tachyarrhythmias to prevent high-rate tracking of the venticule, a total of 45 patients who were preoperatively diagnosed with sick-sinus syndrome (SSS) (Group 1; n = 19) or with advanced or complete atrioventricular block (AVB) (Group 2; n = 26) were followed up and analyzed. Mean follow-up times (mean +/- SD) were 22.4 +/- 9.7 and 12.4 +/- 10.9 months, respectively. Each of the groups was further divided into subgroups according to the preoperative existence of of paroxysmal atrial fibrillation (PAF) or paroxysmal supraventricular tachyarrhythmia (PSVT). During follow-up, the fallback started through a given cycle of ventricular pacing at a upper-rate limit (URL) to avoid a continuous high-rate tracking during the arrhythmias specifically in the patients with PSVT (0/4) (p = 0.0004). The fallback, however, sometimes started in the patients who had AVB not associated with either PAF or PSVT (4/21) during normal exercise because the fallback algorithm did not distinguish a normal P wave from the abnormal atrial waves. To further clarify the behavior of the fallback, a treadmill test was conducted in 25 of the 45 patients. The fallback start was observed in 12 of the 17 patients with AVB (Group 2). In such patients, the use of a long fallback delay and/or a high URL setting prevented the fallback starts during normal exercise. These results suggest that, in DDD pacing, the algorithm in Chorus I is useful in patients with SSS or AVB to avoid highrate tracking of the ventricle during transient supraventricular tachyarrhythmias, but special care must be taken to avoid the fallback starts during the normal exercise in AVB patients.

Adult↗

PubMed1996

A purified protein from Salmonella typhimurium inhibits proliferation of murine splenic anti-CD3 antibody-activated T-lymphocytes.

In previous study, we observed that the purified substance Salmonella typhimurium-derived inhibitor of T-cell proliferation (STI) had an immunosuppressive effect, demonstrated as the suppression of mitogenic lectin-induced proliferation of murine spleen cells. In the present study, we confirmed the immunosuppressive effect of STI, which suppressed the proliferation of murine splenic T-lymphocytes activated with the anti-CD3 antibody (Ab) and phorbol 12-myristate-13 acetate (PMA) and this phenomenon was accompanied by augmentation of interferon-gamma (IFN-gamma) secretion and inhibition of interleukin-2 (IL-2) secretion. Furthermore, the augmentation of IFN-gamma secretion caused IL-2 receptor alpha chain (IL-2R alpha) over expression on T-cells. However, the addition of an anti-IFN-gamma Ab and recombinant IL-2 (rIL-2) did not reverse the suppressed T-cell proliferation, although the level of IL-2R alpha expression on T-cells recovered to around normal. Furthermore, Western blotting using an anti-phosphotyrosine Ab showed that IL-2R-mediated tyrosine phosphorylation of protein substrates in T-cells was inhibited by incubation with STI for 48 h and this inhibition was not reversed by adding the anti-IFN-gamma Ab and rIL-2. These results suggest that STI-induced suppression of T-cell proliferation involves a defect in IL-2R function and/or IL-2 signaling pathway in T-cells.

Animals↗

PubMed1996

Multivariate analysis of prognostic factors in patients with endometrial cancer.

OBJECTIVE: The prognostic factors of endometrial cancer are closely correlated. A multivariate analysis was carried to compare the importance of each factor. METHOD: A multivariate analysis was performed of 19 clinicopathologic prognostic factors obtained from 144 endometrial cancer patients who had been surgically treated in our hospital between January 1971 and December 1993. RESULTS: Significant prognostic factors according to the Kaplan-Meier method were depth of invasion, vascular invasion, nuclear grade, cervical involvement, lymph node metastases, intraperitoneal cytology, serous adenocarcinoma, DNA ploidy, type of hysterectomy and surgery only or combined with chemotherapy or radiotherapy. Multivariate analysis showed that vascular invasion and nuclear grade were more significant than structural grade, histologic subtype or DNA ploidy. CONCLUSION: Multivariate analysis is useful for extracting important recurrent factors from mutually related prognostic factors. Vascular invasion and nuclear grade are singled out as the most useful histologic prognostic factors.

DNA, Neoplasm↗

PubMed1996

[Risk of second primary cancer in two-year survivors of small cell lung cancer].

A total of 498 patients with small cell lung cancer received chemotherapy with or without chest irradiation at Osaka Prefectural Habikino Hospital from October 1977 through December 1991. Sixty-one who survived for more than two years were evaluated to determine the incidence and anatomic patterns of redevelopment of small cell lung cancer and development of second primary cancers. The numbers of expected cancers were estimated by cumulating person years of observation from 2 years after the start of treatment for small cell lung cancer to the date of death. Second primary cancers were observed in seven patients (four cases of non-small cell lung cancer, two of gastric cancer, and one of prostate cancer). The risk of a second primary cancer was 3.2 times greater than in the general population (95% Cl: 1.3-6.6). the relations between occurrence of a second primary cancer and family history of cancer, smoking history, smoking cessation after treatment of small cell lung cancer, and thoracic irradiation were studied. Occurrence of a second primary cancer correlated with family history (relative risk 7.5, 95% Cl: 1.5-22) and smoking cessation (relative risk 3.2, 95% Cl: 1.2-6.9). Long-term survivors were more likely to have a second primary cancer than a relapse of small cell lung cancer. Therefore, long-term survivors should be closely monitored for second primary cancers. Meta-analyses of studies done at several institutions may provide more detailed information on the occurrence of second primary cancers after small cell lung cancer.

Adenocarcinoma↗

PubMed1996

[A catheter-guided insertion of Pacifico's venous cannula].

Direct caval cannulation using a Pecifico's cannula has become popular in open heart surgery. However, the cannulation is often difficult especially in pediatric cases because of the right-angled, blunt and large metal tip of the catheter. To resolve this problem, we introduced a catheter-guided insertion of the cannula using an intratracheal suction catheter (IZUMO Health, Nagano, Japan) of an appropriate size as a guiding catheter. With this technique, no special skills are necessary to establish direct caval cannulation.

Cardiac Surgical Procedures↗

PubMed1996

[Correlation of interleukin-2 (IL-2) responsiveness by egg white-stimulated lymphocytes with hen egg oral provocation test in atopic children].

One hundred and twenty five cases of atopic children such as atopic dermatitis and bronchial asthma were orally provocated with rare hen egg every 20 minutes one by one upto the whole amount. In one week observation 75 cases showed any symptoms of allergy including eruption and exacerbation of atopic eczema in an immediate, late, and/or delayed responses. Frequency of positive egg white-induce IL-2 responsiveness test in patients with positive oral provocation was 90.7% (68 out of 75 cases; sensitivity). That of negative test in patients with negative provocation was 84.0% (42 out of 50 cases; specificity). In contrast, specificity of IgE RAST for egg white were 88.0% comparable to the value of antigen-specific IL-2 responsiveness (AIR) test, but the specificity was lower value (37.3%) for screening the etiological antigens as compared to that of AIR test. High frequency of positive egg white-induced IL-2 responsiveness test was observed over an immediate, late and delayed responses, while low frequency of positive IgE RAST for hen egg was observed largely in patients showing delayed but not immediate response. The results indicate that IgE RAST in this study reflects IgE-mediated immediate type hypersensitivity, whereas AIR test reflects, in addition to immediate responses, late and delayed type hypersensitivity. The combined results suggest that AIR test in hen egg allergy is a useful method in vitro for both screening and determining etiological allergens, and might be able to substitute for provocation test in vivo for which many times, labours, expenses, and patients' risks are required, and to cover IgE RAST which fails to determine etiological allergens in 62.7% of patients with positive oral provocation.

Adolescent↗

PubMed1996

Maternal allergen stimulation suppressed respiratory allergy in offspring: with special reference to allergy related cells in the tonsil.

Pregnant mice and Hartley guinea pigs were immunized with T dependent antigen, heterologous erythrocyte and ovalbumin (OVA), and the active immune responsiveness as well as the allergic symptoms of the offspring were investigated. Guinea pigs were also sensitized to OVA intraperitoneally and subcutaneously with a 100 mg/ml solution of saline containing 5 mg of AI(OH)(3) as an adjuvant. Six weeks after the initial allergen stimulation, systemic and local anaphylaxis as elicited by 1-min aerosol administration of a nebulizer and monitored by macroscopic vision accompanied by a time trial for respiratory and cardiac arrest. Serum antibody levels were tested by passive hemagglutination as well as passive cutaneous anaphylaxis especially for the estimation of IgE levels. Nasal, tonsillar and bronchial tissues were also prepared and fixed, followed by hematoxylin and eosin staining for histological observation. In the offspring of mothers who had been stimulated with optimal amounts of the allergen and had fully developed specific antibodies against the allergen, there was a clear-cut suppression in the development of a specific respiratory allergy over a significant period after delivery. The effect was confirmed by systemic and local anaphylaxis, eosinophil infiltration, ciliary deformation in nasal mucosae and the tonsillar site in the complex interaction of various cell types and mediators eliciting the clinical respiratory symptoms, in particular nasal hypersensitivity. In a different experimental model, the mouse model, these biological findings were not regulated by maternal transferable antibody or antigen fragments from the mother. The induction of suppressor T cell (CD(4+)) in offspring depends on the recognition of the antigens presented in association with the same MHC haplotype as that utilized in the maternal T cell response during pregnancy. These results suggest the presence of suppression mechanisms in the offspring of mothers stimulated during pregnancy. From these results, we discuss the mechanisms for suppression and protective efficacy for respiratory allergy as well as possible side effects in the young of mothers stimulated during pregnancy.

Allergens↗

PubMed1995

Miller-Dieker syndrome due to maternal cryptic translocation t(10;17) (q26.3;p13.3)

We report on a 3-month-old girl with Miller-Dieker syndrome resulting from a maternal full-cryptic translocation t(10;17) (q26.3;p13.3) detectable only by using fluorescence in situ hybridization (FISH). Parental studies using FISH are crucial for genetic counselling in cases of Miller-Dieker syndrome with submicroscopic deletion at 17p13.3. In a family with a parental cryptic translocation and high recurrence risk, parental diagnosis using FISH is feasible.

Abnormalities, Multiple↗

PubMed1995

N-alkylated nitrogen-in-the-ring sugars: conformational basis of inhibition of glycosidases and HIV-1 replication.

The conformations of nitrogen-in-the-ring sugars and their N-alkyl derivatives were studied from 1H NMR analyses, mainly using 3J(H,H) coupling constants and quantitative NOE experiments. No significant difference was seen in the ring conformation of 1-deoxynojirimycin (1), N-methyl-1-deoxynojirimycin (2), and N-butyl-1-deoxynojirimycin (3). However, it was shown that the C6 OH group in 1 is predominantly equatorial to the piperidine ring, while that in 2 or 3 is predominantly axial, and its N-alkyl group is oriented equatorially. In the furanose analogues 1,4-dideoxy-1,4-imino-D-arabinitol (4) and its N-methyl (5) and N-butyl (6) derivatives, the five-membered ring conformation differed significantly by the presence or absence of the N-substituted group and the length of the N-alkyl chain. Compound 3 reduced its inhibitory effect on almost all glycosidases, resulting in an extremely specific inhibitor for processing alpha-glucosidase I since N-alkylation of 1 is known to enhance both the potency and specificity of this enzyme in vitro and in vivo. This preferred (C6 OH axial) conformation in 2 and 3 appears to be responsible for their strong alpha-glucosidase I activity. Compound 4 is a good inhibitor of intestinal alpha-glucohydrolases, alpha-glucosidase II, and Golgi alpha-mannosidases I and II, but its N-alkyl derivatives 5 and 6 markedly decreased inhibitory potential for all enzymes tested. In the case of 2,5-dideoxy-2,5-imino-D-mannitol (DMDP, 7), which is a potent beta-galactosidase inhibitor, its N-methyl (8) and N-butyl (9) derivatives completely lost potency toward beta-galactosidase as well. N-Alkylation of compounds 4 and 7, known well as potent yeast alpha-glucosidase inhibitors, resulted in a serious loss of inhibitory activity toward yeast alpha-glucohydrolases. Activity of these nine analogues against HIV-1 replication was determined, based on the inhibition of virus-induced cytopathogenicity in MT-4 and MOLT-4 cells. Compounds 2 and 3, which are better inhibitors of alpha-glucosidase I than 1, proved active with EC50 values of 69 and 49 micrograms/mL in MT-4 cells and 100 and 37 micrograms/mL in MOLT-4 cells, respectively, while none of the furanose analogues exhibited any inhibitory effects on HIV-1. The change in potency and specificity of bioactivity by N-alkylation of nitrogen-in-the-ring sugars appears to be correlated with their conformational change.

Alkylation↗

PubMed1995

Mapping of the gracile axonal dystrophy (gad) gene to a region between D5Mit197 and D5Mit113 on proximal mouse chromosome 5.

The gracile axonal dystrophy (gad) mouse, which shows hereditary sensory ataxia and motor paresis, has been morphologically characterized by the dying back type of axonal degeneration in the nerve terminals of dorsal root ganglion cells and motor neurons. In the present study, using an intraspecific backcross between gad and C57BL/6J mice, the gracile axonal dystrophy (gad) gene was mapped to a region between D5Mit197 and D5Mit113. Estimated distances between gad and D5Mit197 and between gad and D5Mit113 are 0.4 +/- 0.3 and 5.0 +/- 1.0 cM, respectively. The gene order was defined: centromere-D5Mit81-D5Mit233-D5Mit184/D5Mit254- D5Mit256-D5Mit197-gad-D5Mit113-D5Mit7. The mouse map location of the gad locus appears to be in a region homologous to human 4p15-p16. Our present data suggest that the nearest flanking marker D5Mit197 provides a useful anchor for the isolation of the gad gene in a yeast artificial chromosome contig.

Alleles↗

PubMed1995

Calystegins of Physalis alkekengi var. francheti (Solanaceae). Structure determination and their glycosidase inhibitory activities.

Five calystegins were extracted from the roots of Physalis alkekengi var. francheti (Solanaceae) with hot water and purified to homogeneity by the combination of a variety of ion-exchange column chromatographies. Their structures have been determined from the 1H- and 13C-NMR spectral data, and two of the compounds were identified as calystegins A3 and B2, which have been isolated from the roots of Calystegia sepium (Convolvulaceae). Two of the remaining three were found to be 1 alpha, 3 alpha, 4 beta-trihydroxy-nor-tropane and 1 alpha, 2 alpha, 3 alpha, 4 beta-tetrahydroxy-nor-tropane and given the trivial name calystegins A5 and B3, respectively. The last calystegin was assigned as 1 alpha, 2 beta, 3 alpha, 6 alpha-tetrahydroxy-nor-tropane, which was the same as the relative configuration proposed in the literature for calystegin B1 isolated from C. sepium. However, the 13C-NMR spectral data for the compound from C. sepium differed substantially from our results. From a personal communication with the authors of the original paper on calystegins, it was clarified that the 13C-NMR chemical shifts of calystegin B1 in the original paper had been erroneous. Since their corrected 13C-NMR data of calystegin B1 and its 1H-NMR chemical shifts in the original paper are very close to our present data, we concluded that both compounds from C. sepium and P. alkekengi are identical. Calystegin B2 has been known to be a potent competitive inhibitor of almond beta-glucosidase (Ki = 1.2 microM) and coffee bean alpha-galactosidase (Ki = 0.86 microM). In this study calystegin B1 (1 alpha, 2 beta, 3 alpha, 6 alpha-tetrahydroxy-nor-tropane) proved to be a potent competitive inhibitor of almond beta-glucosidase (Ki = 1.9 microM) and bovine liver beta-galactosidase (Ki = 1.6 microM), but not an inhibitor of alpha-galactosidases. Calystegin A3 was found to be a weaker inhibitor compared to calystegin B2 but with the same inhibitory spectrum. Calystegin A5, a 2-deoxy derivative of calystegin B2, showed no activity against any glycosidases tested. Since calystegin B3, a 2-epimer of calystegin B2, also exhibited only a weak inhibitory activity, it was concluded that the equatorially oriented OH group at C2 is the essential feature for recognition and strong binding by the active site of glycosidases.(ABSTRACT TRUNCATED AT 400 WORDS)

Alkaloids↗

PubMed1995

Involvement of umuDCST genes in nitropyrene-induced -CG frameshift mutagenesis at the repetitive CG sequence in the hisD3052 allele of Salmonella typhimurium.

Expression of the umuDC operon is required for UV and most chemical mutagenesis in Escherichia coli. The closely related species Salmonella typhimurium has two sets of umuDC-like operons, umuDCST on the chromosome and samAB on a 60-MDa cryptic plasmid. The roles of the umuDC-like operons in chemically induced frameshift mutagenesis of the hisD3052 allele of S. typhimurium were investigated. Introduction of a pBR322-derived plasmid carrying umuDCST increased the rate of reversion of hisD3052, following treatment with 1-nitropyrene (1-NP) or 1,8-dinitropyrene (1,8-DNP) tenfold and fivefold, respectively, whereas it did not substantially increase the rate of reversion induced by other frameshift mutagens, i.e. 2-nitrofluorene (2-NF) and 2-amino-3-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1). Introduction of a pBR322-derived plasmid carrying samAB did not increase the incidence of reversion of hisD3052 observed with any of the mutagens examined. Deletion of umuDCST substantially lowered the reversion rate induced by 1-NP or 1,8-DNP, but it did not affect reversion induced by 2-NF, Glu-P-1 or N-hydroxyacetylaminofluorene (N-OH-AAF). Deletion of samAB had little impact on reversion incidence induced by any of the five frameshift mutagens. DNA amplification using the polymerase chain reaction technique followed by restriction enzyme analysis using BssHII, suggested that the mutations induced by the five frameshift mutagens were all CG deletions at the CGCGCGCG sequence in hisD3052. These results suggest that umuDCST, but not samAB, is involved in the -2 frameshift mutagenesis induced by 1-NP and 1,8-DNP at the repetitive CG sequence, whereas neither operon participates in induction of the same type of mutations by 2-NF, Glu-P-1 or N-OH-AAF.

Alcohol Oxidoreductases↗

PubMed1995

Direct determination of E2020 enantiomers in plasma by liquid chromatography-mass spectrometry and column-switching techniques.

High-performance liquid chromatography with column switching and mass spectrometry (MS) was applied to the on-line determination and resolution of the enantiomers of E2020 (acetylcholinesterase inhibitor) in plasma. This system employs two avidin columns and fast atom bombardment (FAB)-MS. A plasma sample was injected directly into an avidin trapping column (10 mm x 4.0 mm I.D.). The plasma protein was washed out from the trapping column immediately while E2020 was retained. After the column-switching procedure, E2020 was separated enantioselectivity in an avidin analytical column. The separated E2020 enantiomers were specifically detected by FAB-MS without interference from metabolites of E2020 and plasma constituents. The limit of quantification for each enantiomer of E2020 in plasma was 1.0 ng/ml and the intra- and inter-assay relative standard deviations for the method were less than 5.2%. The assay was validated for enantioselective pharmacokinetic studies in the dog.

Animals↗