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1.
Front Neurol ; 13: 916944, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36081871

RESUMO

Olfactory dysfunction in the post COVID-19 condition reported worldwide are refractory for some patients. For this reason, appropriate treatment is desired. In this article, we describe two cases of olfactory dysfunction in the post COVID-19 condition that was improved by traditional acupuncture treatment. By using the Yingxiang point (LI20), which is said to improve the sense of smell since ancient times, acupuncture treatment was performed 1-2 times a week in two patients about 6 and 7 months after the diagnosis of COVID-19. Acupuncture needles with a body length of 30 mm and a body diameter of 0.16 mm were inserted about 10 mm deep into the skin. We stimulated LI20 of the right and left sides until the patients felt the de qi sensation (acupuncture resonance), and left needles in the points for about 15 min. Immediately after the acupuncture treatment, the symptoms of olfactory dysfunction were alleviated, and the improvement in olfactory dysfunction lasted for 2-4 days. As the number of acupuncture treatments increased, the time until the flareup of olfactory dysfunction was prolonged, and the symptoms tended to decrease. In our experience, the acupuncture treatment was effective in a short period for treating residual olfactory dysfunction of the post COVID-19 condition, suggesting that acupuncture may serve as an adjunct to modern medical treatment, and it may also be a new option for patients who are resistant to Western medical treatment or unable to continue treatment because of side effects. In conclusion, acupuncture may be a new option for patients who are resistant to modern medical treatment or who are unable to continue treatment because of side effects.

2.
Front Med (Lausanne) ; 8: 790542, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35308037

RESUMO

Aim: In tongue diagnosis, a dark purple tongue and enlarged sublingual vein are important findings of Oketsu (blood stasis). However, the association between the tongue color and the sublingual vein has not been reported. This study investigated the association between the tongue color values and the sublingual vein width using tongue image analyzing system (TIAS) for the objective assessment of blood stasis. Methods: A total of 38 patients (age 68.7 ± 11.3 years, 14 men and 24 women) who visited the Department of Kampo Medicine at Chiba University Hospital were included. Physical findings, blood test results, blood stasis score from medical records, and tongue images obtained with TIAS were analyzed. The patients were classified into two groups: patients with a sublingual vein width of ≤2.5 mm (20 patients) and those with a width of >2.5 mm (18 patients). The physical findings and the blood test results of the two groups were analyzed by Wilcoxon's rank-sum test or χ2-test, whereas logistic regression analysis was used to determine the association between the tongue color values and sublingual vein width. Receiver operating characteristic (ROC) analysis was used to differentiate blood stasis. Results: The color values significantly related to the sublingual vein width (mm) were the P1-L* and P4-L* (darkness of the tongue edge and tongue apex) and the P1-b* and P2-b* (blueness of the tongue edge and tongue posterior). The area under the curve was greater for the combination of the tongue color values and the sublingual vein width than that for either of them. Conclusion: This study demonstrated an objective evaluation of blood stasis in the tongue of patients with dark-blue discoloration and an enlarged sublingual vein. In addition, the combination of the tongue color and the sublingual vein is expected to facilitate a more reliable diagnosis of blood stasis.

3.
Anticancer Res ; 39(2): 687-693, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30711946

RESUMO

BACKGROUND: The ultraviolet A (UVA) spectrum mainly includes the region associated with the phototoxicity of fluoroquinolone antimicrobial agents. This study investigated apoptosis induced with UVA light and enoxacin in HL-60 cells. MATERIALS AND METHODS: HL-60 cells were irradiated by UVA (1.1 mW/cm2) for 20 min in the presence or absence of enoxacin. The induction of apoptosis was investigated by analysing cell morphology, flow cytometry of annexin V-positive cells, DNA ladder formation, and caspase-3 activation. RESULTS: Significant induction of apoptosis, DNA fragmentation, and caspase-3 activation were observed in cells treated with both UVA and enoxacin. UVA-induced apoptosis was significantly suppressed when NaN3, a singlet oxygen scavenger, was present. CONCLUSION: Apoptosis was induced by the combination of UVA and enoxacin in HL-60 cells, and singlet oxygen appears to play an important role in photodynamically-induced apoptosis.


Assuntos
Apoptose , DNA/efeitos dos fármacos , DNA/efeitos da radiação , Enoxacino/farmacologia , Raios Ultravioleta , Caspase 3/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Citometria de Fluxo , Fluoroquinolonas/farmacologia , Sequestradores de Radicais Livres , Células HL-60 , Humanos , Fármacos Fotossensibilizantes/química , Espécies Reativas de Oxigênio , Azida Sódica/química
4.
Anticancer Res ; 37(11): 6407-6413, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29061826

RESUMO

Lomefloxacin (LFX) is a widely used fluoroquinolone antimicrobial agent that plays an important role in the treatment of human and animal infections; however, it has been reported to cause phototoxicity. In this study, we investigated the induction of apoptosis due to ultraviolet A (UVA) light in the presence and absence of LFX in HL-60 human promyelocytic leukemia cells. HL-60 cells were exposed to UVA at an intensity of 1.1 mW/cm2 for 20 min in the presence and absence of LFX, and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Cells treated with 100 µM LFX and UVA clearly showed membrane blebbing and cell shrinkage. The proportion of apoptotic cells was significantly higher in cells treated with both UVA and LFX than in those treated with UVA or LFX alone. In addition, DNA ladder formation and caspase-3 activation were observed in cells treated with both UVA and LFX. A significant reduction in the number of UVA-induced apoptotic cells and caspase-3 activation was observed when histidine was present, which suggested that photodynamically-generated singlet oxygen is an important mediator of apoptosis. These results indicate that the combination of UVA and LFX induces apoptosis in HL-60 cells.


Assuntos
Antineoplásicos/farmacologia , Caspase 3/metabolismo , Fragmentação do DNA , Fluoroquinolonas/farmacologia , Leucemia Promielocítica Aguda/genética , Apoptose , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Terapia Combinada , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Células HL-60 , Humanos , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/terapia , Fotoquimioterapia , Raios Ultravioleta , Terapia Ultravioleta
5.
Theranostics ; 2(9): 880-8, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23082100

RESUMO

In this study, we investigated the induction of apoptosis by ultrasound in the presence of the novel porphyrin derivative DCPH-P-Na(I). HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of DCPH-P-Na(I), and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Reactive oxygen species were measured by means of ESR and spin trapping technique. Cells treated with 8 µM DCPH-P-Na(I) and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas significant morphologic changes were not observed in cells exposed to either ultrasound or DCPH-P-Na(I) alone. Also, DNA ladder formation and caspase-3 activation were observed in cells treated with both ultrasound and DCPH-P-Na(I) but not in cells treated with ultrasound or DCPH-P-Na(I) alone. In addition, the combination of DCPH-P-Na(I) and the same acoustical arrangement of ultrasound substantially enhanced nitroxide generation by the cells. Sonodynamically induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. These results indicate that the combination of ultrasound and DCPH-P-Na(I) induced apoptosis in HL-60 cells. The significant reduction in sonodynamically induced apoptosis, nitroxide generation, and caspase-3 activation by histidine suggests active species such as singlet oxygen are important in the sonodynamic induction of apoptosis. These experimental results support the possibility of sonodynamic treatment for cancer using the induction of apoptosis.

6.
Anticancer Res ; 31(2): 501-6, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21378330

RESUMO

BACKGROUND: The sonodynamically-induced in vitro and in vivo antitumor effects of mono-l-aspartyl chlorin e6 (NPe6) was investigated. MATERIALS AND METHODS: Both in vitro and in vivo antitumor effects were tested in combination with ultrasound at 2 MHz. RESULTS: The rate of ultrasonically-induced damage on isolated sarcoma 180 cells in air-saturated suspension was enhanced two-fold with 80 µM NPe6. The co-administration of 25 mg/kg NPe6 followed by ultrasonic exposure at 2 MHz suppressed the growth of implanted colon 26 cell tumors at an intensity at which ultrasound alone showed only a slight antitumor effect. CONCLUSION: These in vitro and in vivo results suggest that NPe6 is a potential sensitizer for sonodynamic tumor treatment. The enhancement of cell damage by NPe6 was significantly inhibited by histidine, which may suggest reactive oxygen species plays a primary role in sonodynamically-induced antitumor effect.


Assuntos
Antineoplásicos/farmacologia , Porfirinas/farmacologia , Sarcoma 180/terapia , Animais , Terapia Combinada , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos ICR , Sarcoma 180/tratamento farmacológico , Terapia por Ultrassom
7.
Toxicol Lett ; 198(2): 210-5, 2010 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-20599483

RESUMO

In vitro metabolism of bisphenol A (BPA), an weak estrogen, was studied with cryopreserved hepatocytes from rat, monkey and human, and was compared with in vivo metabolism reported. The metabolites identified include a major metabolite, BPA glucuronide (BPAG) and BPA sulfate (BPAS). The metabolic rates of bisphenol A at 20micro the hepatocytes (BPAG plus BPAS, nmol/10(6) cells/h) followed the order of rats (48+12)>monkeys (18+4)>humans (8.6+0.8), respectively. The rate of BPAG formation was much higher than that of BPAS formation in all these species. For the BPAG formation, we have determined the apparent K(m) (microf rats (3), monkeys (7), and humans (5). V(max) (nmol/10(6) cells/h) in hepatocytes followed the order of rats (55)>monkeys (22)>humans (11). The total CL(H) for the hepatic formation of BPAG plus BPAS (L/h/kg BW) estimated by well-stirred model with low f(B) value followed the order of rats (3.0)>monkeys (0.68)>humans (0.27), correlating well with in vivo studies of BPA subcutaneously injected rats and monkeys. This study showed that the cryopreserved hepatocytes could be a useful tool for assessing BPA metabolism and predicting systemic exposure of BPA.


Assuntos
Hepatócitos/metabolismo , Fenóis/metabolismo , Animais , Compostos Benzidrílicos , Técnicas de Cultura de Células , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Criopreservação , Glucuronídeos/química , Glucuronídeos/metabolismo , Hepatócitos/efeitos dos fármacos , Humanos , Macaca fascicularis , Masculino , Taxa de Depuração Metabólica , Estrutura Molecular , Fenóis/química , Fenóis/farmacocinética , Ratos , Ratos Sprague-Dawley , Especificidade da Espécie , Espectrometria de Massas por Ionização por Electrospray
8.
Drug Metab Dispos ; 38(7): 1183-8, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20371639

RESUMO

The contribution of the lung to drug metabolism was investigated in rats and the possibility of prediction of in vivo metabolism from in vitro studies using rat pulmonary microsomes was assessed. Lidocaine, midazolam, or nifedipine was administered to rats at a dose of 10 mg/kg by the intra-arterial, intravenous, and intraportal routes. The pulmonary extraction ratios of lidocaine, midazolam, and nifedipine, calculated from the area under the time-plasma concentration curve (AUC) after the intra-arterial and intravenous administrations, were 39.0 +/- 0.5, 18.3 +/- 0.7, and 12.3 +/- 0.3%, respectively. The hepatic extraction ratios of lidocaine, midazolam, and nifedipine, calculated from the AUC after the intraportal and intravenous administrations, were 68.0 +/- 3.3, 52.6 +/- 0.4, and 13.5 +/- 0.2%, respectively. These results showed that both the liver and the lung contributed to the metabolism of these drugs. The above in vivo pulmonary extraction ratios correlated with the in vitro intrinsic clearance values, which were corrected with the protein unbound ratio in microsomes and plasma, suggesting that pulmonary extraction ratios can be predicted quantitatively from in vitro data. The pulmonary intrinsic clearance values of lidocaine, midazolam, and nifedipine in rat microsomes were lower than their hepatic intrinsic clearance, showing that there was an organ difference in metabolism between the liver and lung. Our results support the importance of the estimation of pulmonary metabolism to predict the total clearance more accurately.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Lidocaína/farmacocinética , Pulmão/metabolismo , Midazolam/farmacocinética , Nifedipino/farmacocinética , Animais , Vias de Administração de Medicamentos , Previsões , Técnicas In Vitro , Lidocaína/administração & dosagem , Masculino , Microssomos/metabolismo , Microssomos Hepáticos/metabolismo , Midazolam/administração & dosagem , Nifedipino/administração & dosagem , Ratos , Ratos Wistar
9.
Cancer Chemother Pharmacol ; 66(6): 1071-8, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20204369

RESUMO

In this study, we investigated the induction of apoptosis by ultrasound in the presence of the photochemically active gallium-porphyrin complex, 7,12-bis(1-decyloxyethyl)-Ga(III)-3,8,13,17-tetramethyl-porphyrin 2,18-dipropionyl diaspartic acid (ATX-70). HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of ATX-70, and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Cells treated with 80 µM ATX-70 and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas significant morphologic changes were not observed in cells exposed to either ultrasound or ATX-70 alone. Also, DNA ladder formation and caspase-3 activation were observed in cells treated with both ultrasound and ATX-70 but not in cells treated with ultrasound or ATX-70 alone. In addition, the combination of ATX-70 and the same acoustical arrangement of ultrasound substantially enhanced nitroxide generation by the cells. Sonodynamically induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. These results indicate that the combination of ultrasound and ATX-70 induces apoptosis in HL-60 cells. The significant reduction in sonodynamically induced apoptosis, nitroxide generation, and caspase-3 activation by histidine suggests that active species such as singlet oxygen are important in the sonodynamic induction of apoptosis.


Assuntos
Apoptose/efeitos dos fármacos , Células HL-60/efeitos dos fármacos , Células HL-60/diagnóstico por imagem , Porfirinas/farmacologia , Terapia por Ultrassom , Caspase 3/efeitos dos fármacos , Caspase 3/metabolismo , Fragmentação do DNA , Combinação de Medicamentos , Espectroscopia de Ressonância de Spin Eletrônica , Eletroforese , Ativação Enzimática/efeitos dos fármacos , Gálio/farmacologia , Histidina/metabolismo , Humanos , Óxidos de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Terapia por Ultrassom/métodos , Ultrassonografia
10.
Drug Metab Pharmacokinet ; 22(6): 409-18, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18159128

RESUMO

Nateglinide is an antidiabetic agent metabolized by CYP2C9 and CYP3A4; hence inhibitors of these CYP isozymes may interact with nateglinide. There are, however, only limited in vitro data on how to predict drug-drug interactions in vivo. We examined the effects of 18 drugs that may be prescribed together with nateglinide (metformin, buformin, aspirin, gemfibrozil, simvastatin, pioglitazone, rosiglitazone, carbamazepine, clarithromycin, gliclazide, clofibrate, fluconazole, bezafibrate, phenylbutazone, nifedipine, famotidine, ibuprofen and miconazole) on the conversion of nateglinide to its major metabolite (N-[trans-4-(1-hydroxy-1-methylethyl)-cyclohexanecarbonyl]-D-phenylalanine) using human liver microsomes. Eight compounds showed a<50% inhibitory effect and we estimated the K(i) values for the remaining 10 compounds. Except for fluconazole and miconazole, 1+I(in, max, u)/K(i) calculated from the K(i) values, was approximately 1 and thus the possibility of a drug-drug interaction was considered low. The value for fluconazole suggested the risk of interaction and agreed with the results of clinical studies in which the AUC of nateglinide increased by 48% when it was co-administered with fluconazole. The present study showed that nateglinide metabolism would hardly be affected by the drugs used in this study, except for miconazole and fluconazole that are potent inhibitors of multiple isoforms of CYPs.


Assuntos
Cicloexanos/metabolismo , Inibidores das Enzimas do Citocromo P-450 , Inibidores Enzimáticos/farmacologia , Hipoglicemiantes/metabolismo , Microssomos Hepáticos/efeitos dos fármacos , Fenilalanina/análogos & derivados , Hidrocarboneto de Aril Hidroxilases/antagonistas & inibidores , Hidrocarboneto de Aril Hidroxilases/metabolismo , Biotransformação , Citocromo P-450 CYP2C9 , Citocromo P-450 CYP3A , Sistema Enzimático do Citocromo P-450/metabolismo , Relação Dose-Resposta a Droga , Interações Medicamentosas , Humanos , Técnicas In Vitro , Cinética , Microssomos Hepáticos/enzimologia , Modelos Biológicos , Nateglinida , Fenilalanina/metabolismo
11.
Drug Metab Dispos ; 33(10): 1477-81, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16014768

RESUMO

Fexofenadine hydrochloride (FEX), a second generation H(1)-receptor antagonist, is mainly eliminated from the liver into bile in unchanged form. Recent studies have shown that FEX can be accepted by human MDR1 (P-glycoprotein), OATP1A2 [organic anion-transporting polypeptide (OATP)-A, and OATP2B1 (OATP-B)] expression systems. However, other transporters responsible for the hepatic uptake of FEX have not yet been identified. In the present study, we evaluated the contribution of OATP family transporters, namely OATP1B1 (OATP2/OATP-C), OATP1B3 (OATP8), and OATP2B1 (OATP-B), to FEX uptake using transporter-expressing HEK293 (human embryonic kidney) cells. The uptake of FEX in OATP1B3-expressing cells was significantly greater than that in vector-transfected cells. On the other hand, OATP1B1- or OATP2B1-mediated uptake of FEX was not statistically significant. OATP1B3-mediated transport could be explained by a one-saturable component with a Michaelis constant (K(m)) of 108 +/- 11 microM. The inhibitory effect of FEX on the uptake of estrone-3-sulfate (E(1)S), cholecystokinin octapeptide (CCK-8), and 17beta-estradiol-17beta-d-glucuronide (E(2)17betaG) was also examined. Both OATP1B1- and OATP1B3-mediated E(2)17betaG uptake was inhibited by FEX. The K(i) values were 148 +/- 61 and 205 +/- 72 microM for OATP1B1 and OATP1B3, respectively. FEX also inhibited OATP1B3-mediated CCK-8 uptake and OATP1B1-mediated E(1)S uptake with a K(i) value of 83.3 +/- 15.3 and 257 +/- 84 microM, respectively, suggesting that FEX could not be used as a specific inhibitor for OATP1B1 and OATP1B3, although FEX was preferentially accepted by OATP1B3. In conclusion, this is, to our knowledge, the first demonstration that OATP1B3 is thought to be a major transporter involved in hepatic uptake of FEX in humans.


Assuntos
Antagonistas dos Receptores Histamínicos H1/farmacologia , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Terfenadina/análogos & derivados , Linhagem Celular , Estradiol/análogos & derivados , Estradiol/metabolismo , Estrona/análogos & derivados , Estrona/metabolismo , Humanos , Fígado/metabolismo , Transportador 1 de Ânion Orgânico Específico do Fígado/genética , Transportador 1 de Ânion Orgânico Específico do Fígado/metabolismo , Proteína 1 Transportadora de Ânions Orgânicos/antagonistas & inibidores , Sincalida/metabolismo , Terfenadina/farmacologia
12.
Drug Metab Pharmacokinet ; 19(1): 62-7, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15499171

RESUMO

The uses for drug delivery systems of two soybean oil fat emulsions prepared with an emulsifying agent, phosphatidyl choline (PC) or Pluronic F-127 (PLU), were examined comparatively in vivo and in vitro. In the presence of lipoprotein lipase (LPL) in vitro, the mean particle size of the PLU emulsion changed less than that of the PC emulsion. The production of non-esterified fatty acid (NEFA) from the PLU emulsion in the presence of LPL was smaller than that from the PC emulsion. These in vitro results indicate that the PLU emulsion is more stable than the PC emulsion. Plasma NEFA concentration following intravenous administration of the emulsions decreased with time for the PC emulsion, but was kept lower and constant for the PLU emulsion, supporting the in vitro stability data. The order of plasma cyclosporine A (CsA) concentration following intravenous administration in the above two emulsions and the mixed solution of polyethylene glycol 400 (PEG) and dimethylamide (DMA) in rats was PLU emulsion>PC emulsion>PEG/DMA solution. The plasma concentration was maintained higher and tissue distribution lower for the PLU emulsion than for other formulations. The uptake of oil violet (OV) into the rat parenchymal cells from the PLU emulsion was approximately half that from the PC emulsion, but the uptake into the Kupffer cells was almost equal in both emulsions. In conclusion, these emulsifying agents can control plasma elimination and tissue distribution of lipophilic drugs included in the emulsion. The use of the emulsion formulation makes it possible to avoid side effects through the reduction of drug uptake into non-targeted tissues.


Assuntos
Ciclosporina/farmacocinética , Sistemas de Liberação de Medicamentos , Emulsificantes/farmacocinética , Óleo de Soja/farmacocinética , Animais , Estabilidade de Medicamentos , Emulsões Gordurosas Intravenosas/administração & dosagem , Lipase Lipoproteica/farmacocinética , Fígado/metabolismo , Masculino , Tamanho da Partícula , Fosfatidilcolinas/farmacocinética , Poloxâmero/farmacocinética , Ratos , Ratos Wistar , Distribuição Tecidual
13.
Pharm Res ; 21(3): 467-75, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15070098

RESUMO

PURPOSE: The characteristics of bile canalicular transport processes for xenobiotic taurine conjugates have not yet been clarified. To elucidate the biliary excretion characteristics of xenobiotic taurine conjugates, we investigated the transport of a novel thromboxane A2 receptor antagonist, Z-335, and its taurine conjugate (Z-335-Tau) across the bile canalicular membrane. METHODS: We examined the uptake of Z-335 and Z-335-Tau by isolated bile canalicular membrane vesicles (CMVs) from Sprague Dawley and Eisai-hyperbilirubinemic rats (EHBRs) which EHBRs have a hereditary defect of canalicular multidrug resistance-associated protein 2 (Mrp2) function. Also, the in vitro and in vivo kinetics of Z-335-Tau uptake and excretion were compared. RESULTS: Z-335 uptake by CMVs from normal rats exhibited marked ATP-dependence, whereas ATP-dependent uptake of Z-335 into CMVs from EHBRs was not observed. In contrast, Z-335-Tau uptake into CMVs from both normal rats and EHBRs was ATP dependent. The initial uptake velocity was concentration-dependent, with an in vitro Michaelis constant for initial uptake of 189 microM, which was similar to the in vivo value. CONCLUSIONS: The biliary excretion of Z-335 involves Mrp2, whereas that of Z-335-Tau involves active transport systems that remain intact in EHBRs and show marked ATP dependence, which ATP-dependent transport is involved in the biliary excretion of Z-335-Tau in vivo.


Assuntos
Receptores de Tromboxano A2 e Prostaglandina H2 , Taurina , Acetatos/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Bile , Transporte Biológico , Transporte Biológico Ativo , Indanos , Fígado/metabolismo , Ratos , Ratos Sprague-Dawley
14.
Drug Metab Pharmacokinet ; 17(1): 75-82, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-15618655

RESUMO

To clarify the cause of the canine individual variability in plasma concentration after oral administration of GTS-21, we evaluated in vitro the metabolism to 4-OH-GTS-21 in liver microsomes of the same individuals from in vivo pharmacokinetic study. First, we applied to the Michaelis-Menten kinetic parameters to a dispersion model, and compared hepatic availability (F(H)) and hepatic clearance (CL(H)) values from in vitro with bioavailability (F), hepatic plasma flow (Q(PH)), and plasma clearance (CL(P)) values from in vivo. The ratios of CL(H) to Q(PH) were ranged 0.74 to 0.94, suggesting that GTS-21 is a hepatic plasma flow-limiting drug. A significant correlation of F(H) and F in the four dogs (r=0.995, p=0.005) indicates that the variability is predominantly caused by GTS-21 O4-demethylase activity. Second, we specified the cytochrome P450 (CYP) enzymes that are involved with the metabolism by chemical inhibition. alpha-Naphthoflavone, furafylline, quinidine, quinine, and troleandomycin significantly inhibited GTS-21 O4-demethylase activity. Thus CYP1A, CYP2D15, and CYP3A12 were involved with O4-demethylation. The variability in control activity decreased on addition of alpha-naphthoflavone and furafylline. Third, we quantified the contents of CYP1A and CYP3A12 by enzyme-linked immunosorbent assay. The content of CYP1A was consistent with GTS-21 O4-demethylase activity. We concluded that canine liver CYP1A causes the individual variability in GTS-21 plasma concentration after oral administration.

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