Tetsuya Saita

Sojo University, Kumamoto, Kumamoto Prefecture, Japan

Are you Tetsuya Saita?

Claim your profile

Publications (26)51.32 Total impact

  • Tetsuya Saita, Masashi Shin, Hiroshi Fujito
    [Show abstract] [Hide abstract]
    ABSTRACT: Imatinib is an oral tyrosine kinase inhibitor used for first-line treatment of chronic myeloid leukemia. Therapeutic drug monitoring targeting trough plasma levels of about 1000 ng/mL may help to optimize imantinib's therapeutic effect. This paper reports a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for a pharmacokinetic evaluation of imatinib. Anti-imatinib antibody was obtained by immunizing rabbits with an antigen conjugated with bovine serum albumin and succinimidyl 4-{(4-methyl-1-piperazinyl)methyl}-benzoate. Enzyme labeling of imatinib with horseradish peroxidase was similarly performed using succinimidyl 4-{(4-methyl-1-piperazinyl)methyl}-benzoate. A simple ELISA for imatinib was developed using the principle of direct competition between imatinib and the enzyme marker for anti-imatinib antibody which had been adsorbed by the plastic surface of a microtiter plate. Serum imatinib concentrations lower than 40 pg/mL were reproducibly measurable using the ELISA. This ELISA was specific to imatinib and showed very slight cross-reactivity (1.2%) with a major metabolite, N-desmethyl imatinib. Using this assay, drug levels were easily measured in the blood of mice after their oral administration of imatinib at a single dose of 50 mg/kg. The specificity and sensitivity of the ELISA for imatinib should provide a valuable new tool for use in therapeutic drug monitoring and pharmacokinetic studies of imatinib.
    Biological & Pharmaceutical Bulletin 01/2013; 36(12):1964-8. · 1.85 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We prepared monoclonal antibodies against N-(γ-maleimidobutyryloxy)succinimide-conjugated vancomycin (VM). The monoclonal antibody was specific for conjugated or free VM. The monoclonal antibody enabled us to develop an immunocytochemical method for detecting the uptake of VM in the rat kidney and liver. Three hours after a single intravenous (i.v.) injection of VM at the therapeutic dose, the immunocytochemistry revealed that VM accumulated in large amounts in both the S1 and S2 segments and in much smaller amounts in the S3 segment of the proximal tubules as well as in the distal tubules and collecting ducts. The drug was detected in the cytoplasm, cytoplasmic irregular granules, nuclei, and microvilli of the proximal tubule cells. The distal tubules and collecting ducts contained scattered swollen cells in which both the nuclei and cytoplasm were heavily immunostained. Twenty-four hours after injection, most of the swollen cells returned back to normal size and had somewhat decreased immunostaining. Also, significant amounts of VM remained accumulated for as long as 8 days postadministration. In the liver, similar drug accumulation was observed in the Kupffer cells and the endothelial cells of the hepatic sinusoids but not in the hepatocytes, suggesting that vancomycin cannot be eliminated via the liver. Immunoelectron microscopic studies demonstrated that in the collecting ducts, uptake of VM occurred exclusively in the lysosomes and cytoplasm of the principal cells and scarcely in the intercalated cells. Furthermore, double fluorescence staining using rats simultaneously administered with VM and gentamicin strongly suggests that both drugs colocalized in lysosomes in the proximal tubule cells of kidneys.
    Antimicrobial Agents and Chemotherapy 09/2012; 56(11):5883-91. · 4.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An in vivo role of the multidrug resistant-associated protein (Mrp2) in rat hepatocytes was examined by immunocytochemistry (ICC) for amoxicillin (AMPC) by the use of the transporter-deficient Eisai hyperbilirubinemic rats (EHBR). The ICC revealed that in the liver of EHBR at 3-h post-administration, amoxicillin accumulated in the cytoplasmic pools and nuclei of the hepatocytes in a characteristic granular morphology on the bile capillaries. However, no amoxicillin was observed on the surface of the lumina ranging from the bile capillaries to the interlobular bile ducts. The drug persisted at least for 6-h after administration. In contrast, in the control rat liver at 3-h post-administration, AMPC-adsorption occurred on such luminal surface, while AMPC accumulated to a less level in both the cytoplasm and nuclei of the hepatocytes. The drug completely disappeared in the hepatocytes at 6-h post-administration. These results strongly suggest that AMPC taken up into the cytoplasm of the hepatocytes excretes via Mrp2 into the bile flow. Furthermore, electron microscopy demonstrated that the lower electron density areas in large sizes, corresponding to the cytoplasmic pools in ICC for AMPC, occurred in the cytoplasm peripheral to the nuclei of the hepatocytes in EHBR at 3-h post-administration, and then disappeared 24 h after administration.
    Journal of molecular histology 03/2012; 43(3):371-8. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper reports a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for pharmacokinetic studies of vindesine (VDS). Anti-VDS antibody was obtained by immunizing rabbits with VDS conjugated with bovine serum albumin using N-[β-(4-diazophenyl) ethyl] maleimide as a heterobifunctional coupling agent. An enzyme marker was similarly prepared by coupling VDS with horseradish peroxidase using N-(4-diazophenyl) maleimide. The detection limit of VDS by ELISA was approximately 24 pg/mL with 50-mL samples. This assay was specific for VDS and showed very slight cross-reactivity with other vinca alkaloids, vincristine (0.18%) and vinblastine (0.11%). The values for the VDS concentrations detected using this assay were comparable with those detected using HPLC. There was a good correlation between the values determined by the two methods. Moreover, ELISA was about 50-fold more sensitive in detecting VDS at lower concentrations. The sensitivity and specificity of ELISA should provide a useful tool for pharmacokinetic studies of VDS.
    YAKUGAKU ZASSHI 01/2012; 132(6):727-32. · 0.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The in vivo role of transporters in drug disposition, in the context of other transporters, and metabolism has not been established. We prepared an anti-bestatin serum against bestatin conjugated to albumin with glutaraldehyde (GA). The antiserum was specific for GA-conjugated bestatin and weakly reacted with free bestatin, but no reaction occurred with structurally unrelated compounds according to both the inhibition and binding ELISAs. The antiserum allowed us to develop an immunocytochemical (ICC) method for detecting the uptake of bestatin in the rat intestine and kidney. Three hours after a single oral administration of bestatin, the ICC method revealed that the drug distributed in the microvilli, cytoplasm and nuclei of the absorptive epithelial cells at much larger amounts than in all other cell types in the small intestine. However, no drug was detected in the mucin goblets in the epithelium. In the kidney, the drug distributed to a greater extent in the S3 segment than in the S1 and S2 segments of the proximal tubule, and also was detected in the microvilli of the proximal tubule cells (S1, S2 and S3). These findings that bestatin accumulated in large amounts, especially in the cells and/or at the sites where the transporters PEPT1 and PEPT2 occur, corresponded well to those observed with β-lactam amoxicillin in the previous ICC studies. Thus, this may indicate a possibility that both the transporters might be involved, at least in part, in the distribution of bestatin in the small intestine and kidney under the conditions examined.
    Journal of molecular histology 12/2011; 42(6):589-96. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Peplomycin (PEP), an anti-tumor antibiotic related structurally to bleomycin, is widely used, especially for squamous cell carcinoma but shows renal toxicity. We prepared monoclonal antibodies (mAbs) against N-(γ-maleimidobutyryloxy)succinimide-conjugated PEP. The mAbs were monospecific for PEP, but did not react with bleomycin and other anticancer antibiotics. The mAbs enabled us to develop an immunocytochemical (ICC) method for detecting the uptake of PEP in the rat kidney. Two hours after a single i.v. administration of PEP, ICC revealed immunostaining for PEP in irregularly shaped cytoplasmic granules of the proximal tubules in which the microvilli were also stained. Also, staining occurred in the distal tubules and collecting ducts, in both of which we observed scattered swollen cells, reminiscent of necrotic cells, in which both the nuclei and cytoplasm reacted strongly with the antibody. Twenty-four hours after injection, PEP in the proximal tubules completely vanished, but yet significant amounts of PEP remained in both the distal tubules and collecting ducts. Distribution patterns of PEP in cells of the kidneys resembled, in some ways, those of our recent ICC studies for an organic cation aminoglycoside antibiotic gentamicin. This ICC suggests that PEP taken up in the proximal tubule cells is localized in the lysosomes, and organic cation transporters and bleomycin hydrolase might be involved in entrance and/or disappearance of PEP in this cell type. Furthermore, the distal tubules and collecting ducts may be the sites readily affected by some chemotherapeutic agents.
    Histochemie 01/2011; 135(1):93-101. · 2.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Gentamicin (GM) is a widely used antibiotic but shows renal toxicity. We produced a serum against GM (anti-GM) conjugated to bovine serum albumin with N-(gamma-maleimidobutyryloxy)succinimide. The antiserum was monospecific for GM and did not cross-react with the analog streptomycin, tobramycin, kanamycin, or amikacin. The antiserum also detected glutaraldehyde-fixed GM, and this enabled us to develop an immunocytochemical method for detecting the uptake of GM in rat kidney. Twelve hours after a single intravenous administration of GM, immunocytochemistry revealed that GM accumulated in the S1, S2, and S3 segments of the proximal tubules, as well as in the distal tubules and collecting ducts. By 12 h after injection, the drug was detected in cytoplasmic granules of the proximal tubule cells. However, early (1 h) after injection, drug accumulation was detected in the microvilli of these cells. The distal tubules and collecting ducts contained scattered swollen cells, reminiscent of necrotic cells, in which both the nuclei and the cytoplasm reacted strongly with GM. No staining occurred in the kidneys of saline-injected control rats. These results agree with previous studies showing that GM is endocytosed in the proximal tubules and accumulates in lysosomes. Additionally, our results show that GM also accumulates in the distal tubules and collecting ducts. This was achieved by systematically varying the pretreatment conditions-an approach necessary for detecting GM in different subcellular compartments. This approach should be useful for accurately detecting the uptake and toxicity of the antibiotic in different tissues.
    Antimicrobial Agents and Chemotherapy 06/2009; 53(8):3302-7. · 4.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have developed an enzyme-linked immunosorbent assay (ELISA) suitable for routine monitoring of serum levels of cibenzoline. Anti-cibenzoline antibody was obtained by immunizing rabbits with cibenzoline conjugated with bovine serum albumin using N-(4-maleimidobutyryloxy)succinimide as a heterobifunctional coupling agent. An enzyme marker was prepared by coupling 2,2-diphenylethylamine with beta-D-galactosidase using glutaraldehyde. The detection limit of cibenzoline by ELISA was approximately 640 pg/ml with 50-microl samples. Cross-reactivity data showed that the antibody well recognizes both the diphenyl and cyclopropyl moieties, and is thus specific enough to the structure of cibenzoline. The values for the cibenzoline concentrations detected using this assay were comparable with those detected using HPLC. There was a good correlation between the values determined by the two methods. Moreover, ELISA was about 15-fold more sensitive in detecting cibenzoline at lower concentrations. Using this assay, drug levels were easily measured in the serum of rabbits after oral administration of cibenzoline at a single dose of 3 mg/kg.
    Yakugaku zasshi journal of the Pharmaceutical Society of Japan 07/2007; 127(6):1007-12. · 0.46 Impact Factor
  • Tetsuya Saita, Hiroshi Fujito, Masato Mori
    [Show abstract] [Hide abstract]
    ABSTRACT: The epidermal growth factor tyrosine kinase inhibitor gefitinib is a novel, molecularly targeted agent that has been approved for the treatment of advanced non-small cell lung cancer. This paper reports a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for pharmacokinetic studies of gefitinib. Anti-gefitinib antibody was obtained by immunizing rabbits with an antigen conjugated with bovine serum albumin using diazotized 4-amino-2-methoxy-1-[3-(morpholin-4-yl)propoxy]benzene. Enzyme labeling of gefitinib with beta-D-galactosidase was similarly performed using a diazotized 4-amino-2-methoxy-1-[3-(morpholin-4-yl)propoxy]benzene. A simple ELISA for gefitinib was developed using the principle of direct competition between gefitinib and the enzyme marker for anti-gefitinib antibody which had been adsorbed to the plastic surface of a microtiter plate. Gefitinib concentrations in serum lower than 800 pg/ml were measurable reproducibly using the ELISA. Cross-reactivity data showed that the antibody well recognizes both the 3-morpholinopropoxy and methoxy moieties well, and thus is sufficiently specific for the structure of gefitinib. Using this assay, drug levels were easily measured in the serum of rabbits after oral administration of gefitinib at a single dose of 5 mg/kg. The specificity and sensitivity of the ELISA for gefitinib should provide a valuable new tool for use in pharmacokinetic and toxicity studies of gefitinib.
    Biological & Pharmaceutical Bulletin 11/2005; 28(10):1833-7. · 1.85 Impact Factor
  • Tetsuya Saita, Hiroshi Fujito, Masato Mori
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper reports a sensitive and specific enzyme-linked immunosorbent assay for screening of furanocoumarin derivatives as cytochrome P450 3A4 inhibitors in citrus fruits. Anti-6',7'-dihydroxybergamottin antibody was obtained by immunizing rabbits with 6',7'-dihydroxybergamottin conjugated with bovine serum albumin using the N-succinimidyl ester method. An enzyme marker was similarly prepared by coupling 6',7'-dihydroxybergamottin with beta-D-galactosidase. The enzyme-linked immunosorbent assay is capable of detecting as little as 800 pg/ml of 6',7'-dihydroxybergamottin and 4 ng/ml of bergamottin. Cross-reactivity data showed that the antibody well recognizes both the furanocoumarin and 6,7-dihydroxy-3,7-dimethyloct-2-enyloxy moieties of the 6',7'-dihydroxybergamottin, and is thus specific to the structure of furanocoumarin derivatives containing geranyloxy side chain as the cytochrome P450 3A4 inhibitors in grapefruit juice. The antibody was, therefore, used for screening a large number of citrus fruits for furanocoumarin derivatives such as 6',7'-dihydroxybergamottin. Fifteen citrus fruits were examined and significant reactivity was observed in 8 of these: red pummelo, sweetie, melogold, banpeiyu pummelo, hassaku, sour orange, lime and natsudaidai. This enzyme-linked immunosorbent assay may be a powerful tool for screening for furanocoumarin derivatives as cytochrome P450 3A4 inhibitors in grapefruit juice.
    Biological & Pharmaceutical Bulletin 08/2004; 27(7):974-7. · 1.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A selective liquid chromatographic method has been developed for the assay of ethambutol in serum samples. The assay involves intramolecular excimer-forming derivatization with 4-(1-pyrene)butanoyl chloride (PBC) and isocratic reversed-phase chromatography with fluorescence detection. After acetonitrile-deproteinization of the serum sample, the derivatization reaction of ethambutol with PBC was completed within 30 min at 50 degrees C. N,N'-Diethylethylenediamine was used as an internal standard. The detection limit of ethambutol was 23 ng/ml serum, corresponding to 180 fmol on column at a signal-to-noise ratio of 3. The present method was selective enough to analyze ethambutol in rabbit serum without any tedious sample clean-up procedure because biogenic monoamines gave no peak in the chromatogram. The method was applicable to drug monitoring in rabbit serum.
    Analytical Sciences 04/2004; 20(3):489-93. · 1.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have established an enzyme-linked immunosorbent assay suitable for routine monitoring of serum levels of sotalol. Anti-sotalol antibody was obtained by immunizing rabbits with sotalol conjugated with bovine serum albumin using the N-succinimidyl ester method. An enzyme marker was similarly prepared by coupling sotalol with beta-D-galactosidase. The detection limit of sotalol by the enzyme-linked immunosorbent assay was approximately 32 ng/ml with 50-microl samples. This assay was specific for sotalol because of very slight cross-reactivity with 4-(methanesulfonylamino)benzonitrile (1.6%), but none with D,L-isoproterenol. Using this assay, drug levels were easily measured in the serum of rabbits after oral administration of sotalol at a single dose of 3 mg/kg. The enzyme-linked immunosorbent assay should be a valuable tool in therapeutic drug monitoring and pharmacokinetic studies of sotalol.
    Biological & Pharmaceutical Bulletin 02/2004; 27(1):94-6. · 1.85 Impact Factor
  • Tetsuya Saita, Hiroshi Fujito, Masato Mori
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper reports a sensitive and specific enzyme-linked immunosorbent assay for determination of the antiarrhythmic drug mexiletine in human serum. Anti-mexiletine antibody was obtained by immunizing rabbits with an antigen conjugated with mercaptosuccinyl bovine serum albumin using N-(epsilon-maleimidocaproyloxy)succinimide as a heterobifunctional coupling agent. Enzyme labeling of mexiletine with beta-D-galactosidase was performed using glutaraldehyde. In this assay, the mexiletine to be quantified is chemically modified by acetic anhydride allowed to compete with a mexiletine-beta-D-galactosidase conjugate for binding to a limited amount of an anti-mexiletine antibody which was used to coat the wells of a microtiter plate. Mexiletine concentrations lower than 80 ng/ml were measurable reproducibly by the enzyme-linked immunosorbent assay. This assay was specific for mexiletine and showed very slight cross-reactivity with its major metabolite, 2-hydroxymethylmexiletine (1.5%), but none with p-hydroxymexiletine. The values of serum mexiletine levels from 15 patients by this enzyme-linked immunosorbent assay were comparable with those measured by HPLC. There was a good correlation between the values determined by the two methods. The enzyme-linked immunosorbent assay should be a valuable tool in therapeutic drug monitoring and pharmacokinetic studies of mexiletine.
    Biological & Pharmaceutical Bulletin 07/2003; 26(6):761-5. · 1.85 Impact Factor
  • Tetsuya Saita, Hiroshi Fujito, Masato Mori
    [Show abstract] [Hide abstract]
    ABSTRACT: A sensitive and specific enzyme-linked immunosorbent assay for an antiarrhythmic drug, amiodarone (AMI), was developed, which is capable of measuring levels as low as 16 ng/ml. Anti-AMI antibody was obtained by immunizing rabbits with an antigen conjugated with bovine serum albumin using diazotized 4-amino-1-(2-diethylaminoethoxy)-2,6-diiodobenzene. Enzyme labeling of AMI with beta-D-galactosidase was similarly performed using a diazotized 4-amino-1-(2-diethylaminoethoxy)-2,6-diiodobenzene. This enzyme-linked immunosorbent assay was specific for AMI and showed a very slight cross-reactivity (1.25%) with its major metabolite, mono-N-desethylamiodarone. The values of the AMI concentrations measured by this assay were in good correlation to those by HPLC. Its analytical applicability was demonstrated by a kinetic study with human liver microsomes. The enzyme-linked immunosorbent assay should be a valuable tool in therapeutic drug monitoring and pharmacokinetic studies of AMI.
    Biological & Pharmaceutical Bulletin 09/2002; 25(8):954-8. · 1.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A highly selective and simple fluorimetric liquid chromatographic method for the determination of triethylenetetramine (TETA), a therapeutic drug for Wilson's disease, in human and rabbit sera is described. This method is based on intramolecular excimer-forming fluorescence derivatization, which allows spectrofluorometric discrimination of polyamino compounds from monoamino species, followed by liquid chromatography. TETA and 1,6-hexanediamine (internal standard) were converted to the corresponding excimer-forming derivatives with a pyrene reagent, 4-(1-pyrene)butyric acid N-hydroxysuccinimide ester. The derivatives were separated within 20 min on a reversed-phase column using isocratic elution and detected spectofluorometrically at 480 nm with excitation at 345 nm. This method was successfully applied to the monitoring of TETA in human and rabbit sera with a simple pretreatment. The detection limit for TETA in serum was 18 ng/ml (0.13 nmol/ml) corresponding to 0.2 pmol on column at a signal-to-noise ratio of 3.
    Journal of Chromatography B 08/2002; 774(2):165-72. · 2.49 Impact Factor
  • T Saita, H Fujito, M Mori
    [Show abstract] [Hide abstract]
    ABSTRACT: A sensitive and specific ELISA for an antiarrhythmic drug, pilsicainide, was developed, which is capable of measuring as low as 1.6 ng/ml. Anti-pilsicainide antibody was obtained by immunizing rabbits with pilsicainide conjugated with bovine serum albumin using diazotized N-(3-amino-2,6-dimethylphenyl)-8-pyrrolizidinylacetamide (3-aminopilsicainide). Enzyme labeling of pilsicainide with beta-D-galactosidase was similarly performed using a diazotized 3-aminopilsicainide. Cross-reactivity data showed that the antibody well recognizes both the aromatic ring and the pyrrolizidine moieties, and thus specific enough to the structure of pilsicainide. The values for the pilsicainide concentrations detected using this assay were comparable with those detected using HPLC. There was a good correlation between the values determined by the two methods. Moreover, the ELISA was about 30-fold more sensitive in detecting pilsicainide at lower concentrations. Using this assay, drug levels were easily measured in the serum of rabbits after oral administration of pilsicainide at a single dose of 1 mg/kg. The ELISA should be a valuable tool in therapeutic drug monitoring (TDM) and pharmacokinetic studies of pilsicainide.
    Biological & Pharmaceutical Bulletin 11/2001; 24(10):1113-6. · 1.85 Impact Factor
  • T Saita, H Fujito, M Mori
    [Show abstract] [Hide abstract]
    ABSTRACT: A highly sensitive ELISA for the determination of (s)-9-dimethylaminomethyl-10-hydroxy-camptothecin (topotecan) capable of measuring as low as 80 pg/ml was developed. Anti-topotecan antibody was obtained by immunizing rabbits with topotecan conjugated with bovine serum albumin using diazotized m-aminobenzoic acid as a cross-linker. Enzyme labeling of topotecan with beta-D-galactosidase was performed by utilizing another cross-linker, N-(4-diazophenyl)maleimide. The specificity of this ELISA appears to be primarily toward the lactone moiety of topotecan, showing a very slight cross-reactivity with the lactone opened-ring of topotecan. The values for the topotecan concentrations detected using this assay were comparable with those detected using HPLC. There was a good correlation between the values determined by the two methods. These findings suggest that this ELISA can detect the natural amounts of the lactone form. Using this assay, drug levels were easily determined in the blood and urine of rats for 5 h after i.v. administration of topotecan at a single dose of 1 mg/kg. The sensitivity and specificity of the ELISA should provide a useful tool for developing pharmacokinetic and pharmacodynamic studies of topotecan.
    Biological & Pharmaceutical Bulletin 05/2001; 24(4):321-6. · 1.85 Impact Factor
  • T Saita, H Fujito, M Mori
    [Show abstract] [Hide abstract]
    ABSTRACT: Two highly sensitive and specific enzyme-linked immunosorbent assays (ELISAs) for the determination of 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothecin (irinotecan) and 7-ethyl-10-hydroxycamptothecin (SN-38), an active metabolite of irinotecan, were developed, which are capable of measuring as low as 16 and 160 pg of each drug/ml, respectively. Anti-irinotecan antibody was obtained by immunizing rabbits with irinotecan conjugated with mercaptosuccinyl bovine serum albumin (MS.BSA) using N-(4-diazophenyl)maleimide (DPM) as a heterobifunctional coupling agent. An enzyme marker was similarly prepared by coupling irinotecan with horseradish peroxidase (HRP) via DPM. This ELISA for irinotecan was specific for irinotecan and showed almost no cross-reactivity with its active metabolite SN-38. Anti-SN-38 antibody was obtained by immunizing rabbits with SN-38 conjugated with BSA using the N-succinimidyl ester method. An enzyme marker was prepared by coupling SN-38 with HRP employing DPM. The ELISA for SN-38 was specific to SN-38 and showed a very slight cross-reactivity with irinotecan (0.08%). Using the 2 assays, we reconfirmed the rapid metabolite of irinotecan with rat serum. The 2 ELISAs may be a valuable tool for studies of the pharmacokinetics and pharmacodynamics of these drugs.
    Biological & Pharmaceutical Bulletin 09/2000; 23(8):911-6. · 1.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A highly sensitive ELISA for the determination of polymyxin B sulfate (PMB) was developed which is capable of measuring as low as 32 pg/ml. Anti-PMB antibody was obtained by immunizing rabbits with PMB conjugated with mercaptosuccinyl bovine serum albumin (MS. BSA) using N-(gamma-maleimidobutyryloxy) succinimide (GMBS) as a heterobifunctional coupling agent. An enzyme marker was similarly prepared by coupling PMB with horseradish peroxidase (HRP) employing GMBS. This ELISA showed very low reactivity with the PMB analogue, polymyxin E (0.05%). The values for PMB concentration detected by this assay were comparable with those detected by the bioassay. Moreover, the ELISA was about 10,000 times more sensitive in detecting PMB at lower concentrations. Serum PMB concentration after the oral administration of a PMB tablet to human subjects was determined by the ELISA. PMB was rapidly absorbed from the gastrointestinal tract after the administration, then slowly decreased. These results indicate that the ELISA may be a valuable tool for studies of the pharmacokinetics and pharmacodynamics of the anti-endotoxin drug, PMB.
    Biological & Pharmaceutical Bulletin 01/2000; 22(12):1257-61. · 1.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Methanol extracts of 36 samples of 21 Umbelliferae plants were screened for polyacetylenic compounds using the ELISA for panaxytriol, and their antiproliferative activity was checked by MTT assay using the tumor cell lines MK-1, HeLa and B16F10. The presence of antiproliferative polyacetylenes was suggested in Angelica acutiloba (fruit), Anethum graveolens (root), Bupleurum rotundifolium (fruit), Carum carvi (fruit and root), Coriandrum sativum (fruit), Cryptotaenia japonica (leaf), Glehnia littoralis (fruit), Heracleum moellendorffii (root) and Torilis japonica (fruit). Panaxynol and falcarindiol were successfully isolated from the root of Heracleum moellendorffii as antiproliferative polyacetylenes.
    Biological & Pharmaceutical Bulletin 04/1998; 21(3):257-61. · 1.85 Impact Factor