87 results on '"Ikuo Horii"'
Search Results
2. Microphysiological systems in early stage drug development: Perspectives on current applications and future impact
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Christine P. Bono, Mazin Derzi, Lindsay Tomlinson, Bart Jessen, Anna K. Kopec, James E. Finley, Ikuo Horii, John E. Burkhardt, Shuyan Lu, Carol B. Donovan, Julie Harney, Mark Collinge, Andrew D. Burdick, Ryuji Yokokawa, Ramin Banan Sadeghian, Nasir K. Khan, and Jessica Roy
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congenital, hereditary, and neonatal diseases and abnormalities ,Drug Industry ,Computer science ,Context (language use) ,010501 environmental sciences ,Toxicology ,030226 pharmacology & pharmacy ,01 natural sciences ,Models, Biological ,Toxicology studies ,03 medical and health sciences ,Organ-chips ,0302 clinical medicine ,Drug Development ,Lab-On-A-Chip Devices ,Animals ,Humans ,skin and connective tissue diseases ,Drug safety ,Organ system ,0105 earth and related environmental sciences ,Pharmaceutical industry ,Biological Products ,business.industry ,nutritional and metabolic diseases ,Complex in vitro models ,Microfluidic Analytical Techniques ,Physiological responses ,Risk analysis (engineering) ,Drug development ,Microphysiological systems ,business ,Forecasting - Abstract
Microphysiological systems (MPS) are making advances to provide more standardized and predictive physiologically relevant responses to test articles in living tissues and organ systems. The excitement surrounding the potential of MPS to better predict human responses to medicines and improving clinical translation is overshadowed by their relatively slow adoption by the pharmaceutical industry and regulators. Collaboration between multiorganizational consortia and regulators is necessary to build an understanding of the strengths and limitations of MPS models and closing the current gaps. Here, we review some of the advances in MPS research, focusing on liver, intestine, vascular system, kidney and lung and present examples highlighting the context of use for these systems. For MPS to gain a foothold in drug development, they must have added value over existing approaches. Ideally, the application of MPS will augment in vivo studies and reduce the use of animals via tiered screening with less reliance on exploratory toxicology studies to screen compounds. Because MPS support multiple cell types (e.g. primary or stem-cell derived cells) and organ systems, identifying when MPS are more appropriate than simple 2D in vitro models for understanding physiological responses to test articles is necessary. Once identified, MPS models require qualification for that specific context of use and must be reproducible to allow future validation. Ultimately, the challenges of balancing complexity with reproducibility will inform the promise of advancing the MPS field and are critical for realization of the goal to reduce, refine and replace (3Rs) the use of animals in nonclinical research.
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- 2021
3. Current status and future perspective of computational toxicology in drug safety assessment under ontological intellection
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Hiroshi Yamada, Ikuo Horii, and Yuki Yamagata
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Computer science ,Data management ,Big data ,010501 environmental sciences ,computer.software_genre ,Toxicology ,030226 pharmacology & pharmacy ,01 natural sciences ,03 medical and health sciences ,0302 clinical medicine ,Drug Development ,Drug Discovery ,Humans ,0105 earth and related environmental sciences ,business.industry ,Mechanism (biology) ,Computational Biology ,Expert system ,Explication ,Risk analysis (engineering) ,Drug development ,Biological Ontologies ,Ontology ,Good laboratory practice ,business ,computer - Abstract
For the safety assessment of pharmaceuticals, initial data management requires accurate toxicological data acquisition, which is based on regulatory safety studies according to guidelines, and computational systems have been developed under the application of Good Laboratory Practice (GLP). In addition to these regulatory toxicology studies, investigative toxicological study data for the selection of lead compound and candidate compound for clinical trials are directed to estimation by computational systems such as Quantitative Structure-Activity Relationship (QSAR) and related expert systems. Furthermore, in the "Go" or "No-Go" decision of drug development, supportive utilization of a scientifically interpretable computational toxicology system is required for human safety evaluation. A pharmaceutical safety evaluator as a related toxicologist who is facing practical decision needs not only a data-driven Artificial Intelligence (AI) system that calls for the final consequence but also an explainable AI that can provide comprehensive information necessary for evaluation and can help with decision making. Through the explication and suggestion of information on the mechanism of toxic effects to safety assessment scientists, a subsidiary partnership system for risk assessment is ultimately to be a powerful tool that can indicate project-vector with data weight for the corresponding counterparts. To bridge the gaps between big data and knowledge, multi-dimensional thinking based on philosophical ontology theory is necessary for handling heterogeneous data for integration. In this review, we will explain the current state and future perspective of computational toxicology related to drug safety assessment from the viewpoint of ontology thinking.
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- 2019
4. The principle of safety evaluation in medicinal drug - how can toxicology contribute to drug discovery and development as a multidisciplinary science?
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Ikuo Horii
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0301 basic medicine ,Sociology of scientific knowledge ,Risk Management ,Drug-Related Side Effects and Adverse Reactions ,business.industry ,Drug discovery ,Translational research ,Precision medicine ,Toxicology ,Biomarkers, Pharmacological ,Evidence-based toxicology ,03 medical and health sciences ,Molecular Toxicology ,030104 developmental biology ,Adverse Outcome Pathway ,Drug Discovery ,Product Surveillance, Postmarketing ,Medicine ,Humans ,Interdisciplinary Communication ,Molecular Targeted Therapy ,business ,Risk management - Abstract
Pharmaceutical (drug) safety assessment covers a diverse science-field in the drug discovery and development including the post-approval and post-marketing phases in order to evaluate safety and risk management. The principle in toxicological science is to be placed on both of pure and applied sciences that are derived from past/present scientific knowledge and coming new science and technology. In general, adverse drug reactions are presented as "biological responses to foreign substances." This is the basic concept of thinking about the manifestation of adverse drug reactions. Whether or not toxic expressions are extensions of the pharmacological effect, adverse drug reactions as seen from molecular targets are captured in the category of "on-target" or "off-target", and are normally expressed as a biological defense reaction. Accordingly, reactions induced by pharmaceuticals can be broadly said to be defensive reactions. Recent molecular biological conception is in line with the new, remarkable scientific and technological developments in the medical and pharmaceutical areas, and the viewpoints in the field of toxicology have shown that they are approaching toward the same direction as well. This paper refers to the basic concept of pharmaceutical toxicology, the differences for safety assessment in each stage of drug discovery and development, regulatory submission, and the concept of scientific considerations for risk assessment and management from the viewpoint of "how can multidisciplinary toxicology contribute to innovative drug discovery and development?" And also realistic translational research from preclinical to clinical application is required to have a significant risk management in post market by utilizing whole scientific data derived from basic and applied scientific research works. In addition, the significance for employing the systems toxicology based on AOP (Adverse Outcome Pathway) analysis is introduced, and coming challenges on precision medicine are to be addressed for the new aspect of efficacy and safety evaluation.
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- 2017
5. MicroRNAs expression in the Ethylene Glycol Monomethyl Ether-induced testicular lesion
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Kenji Taki, Takemi Yoshida, Ikuo Horii, Ryota Ise, and Tamio Fukushima
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Male ,Programmed cell death ,Time Factors ,Cell ,Gene Expression ,Apoptosis ,Biology ,Real-Time Polymerase Chain Reaction ,Toxicology ,Epigenesis, Genetic ,Lesion ,Andrology ,Testis ,Toxicity Tests ,Gene expression ,medicine ,Animals ,Spermatogenesis ,Sertoli Cells ,Dose-Response Relationship, Drug ,Chemistry ,Rats, Inbred Strains ,General Medicine ,Sertoli cell ,Spermatozoa ,Molecular biology ,Rats ,MicroRNAs ,medicine.anatomical_structure ,Organ Specificity ,Ethylene Glycols ,medicine.symptom ,Pyknosis - Abstract
Ethylene glycol monomethyl ether (EGME) induces testicular lesion in rats and human. To investigate miRNAs expression in EGME testicular lesion, miRNA array assay and real-time RT-PCR analysis were conducted by using testis in rats treated with 50 and 2,000 mg/kg EGME for 6 and 24 hr. The expression of corresponding target gene for miRNAs was also examined. At 50 mg/kg, there were no changes in the gene expression and histopathological examination. At 2,000 mg/kg, slight decrease of phacytene spermatocytes with cell shrinkage and nucleus pyknosis at 6 hr and remarkable decrease (or cell death) of phacytene spermatocytes with Sertoli cell vacuolation at 24 hr were observed. After 24 hr, miR-449a and miR-92a decreased obviously and, miR-320, miR-134 and miR-188 increased, while only miR-760-5p increased after 6 hr. Above these miRNAs are reported to have an important role for spermatogenesis. The gene expression of Bcl-2, target for miR-449a, increased and therefore it is considered anti-apoptotic reaction has started in this stage. The expression of high mobility group AT-hook 2 (target of miR-92a) which regulates histone structure, was increased. Furthermore, histone deacethylase 4, targets for miR-320, was also affected. Above prohibiting apoptosis or activating epigenetic genes might be protective reaction to spermatocytes death under the miRNAs regulation in EGME testicular lesion.
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- 2011
6. Human Hepatocytes Can Repopulate Mouse Liver: Histopathology of the Liver in Human Hepatocyte-Transplanted Chimeric Mice and Toxicologic Responses to Acetaminophen
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Chise Tateno, Hiroshi Yamada, Kazuhide Iwasaki, Katsutoshi Yoshizato, Ikuo Horii, Tsuyoshi Yokoi, and Sato Yasushi
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Male ,Pathology ,medicine.medical_specialty ,Necrosis ,Ratón ,Transgene ,Apoptosis ,Mice, Transgenic ,Mice, SCID ,Toxicology ,Pathology and Forensic Medicine ,Mice ,medicine ,Animals ,Humans ,Molecular Biology ,Acetaminophen ,Cell Proliferation ,Mice, Inbred ICR ,Transplantation Chimera ,Severe combined immunodeficiency ,biology ,Cytochrome P450 ,Cell Biology ,Analgesics, Non-Narcotic ,medicine.disease ,Immunohistochemistry ,Urokinase-Type Plasminogen Activator ,Molecular biology ,Transplantation ,Microscopy, Electron ,medicine.anatomical_structure ,Liver ,Hepatocyte ,Hepatocytes ,biology.protein ,Female ,medicine.symptom ,Plasminogen activator - Abstract
A human hepatocyte-transplanted chimeric mouse has been established by transplantation of human hepatocytes to urokinase-type plasminogen activator transgenic/severe combined immunodeficiency (uPA+/+/SCID) mice. These chimeric mice have various amounts of human hepatocytes that proliferate extensively and progressively replace mouse hepatocytes. In the chimeric liver, hepatic cords and sinusoid-like structures were observed. The human hepatocytes expressed human albumin, human cytochrome P450 enzymes, and human transporter proteins. Furthermore, electron microscopic analysis demonstrated bile canaliculi associated with human hepatocytes in the chimeric mouse livers. These results indicate that the chimeric mouse livers contain functionally intact and differentiated human hepatocytes. Additionally, the toxicologic response of hepatocytes to acetaminophen (APAP) administration was compared in normal and chimeric mouse livers. Following 1,400 mg/kg APAP, mild hepatocellular degeneration was observed in the human hepatocyte areas in the chimeric mice, compared with severe centrilobular hepatocellular necrosis in the ICR mouse livers. In conclusion, these chimeric livers contain functionally differentiated human hepatocytes, and are less susceptible to APAP toxicity, compared to ICR mice.
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- 2008
7. In vitro gene expression analysis of hepatotoxic drugs in rat primary hepatocytes
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Yoko Hirabayashi, Tomochika Matsushita, Tohru Inoue, Ikuo Horii, Kazuko Kobayashi, Hiromi Suzuki, and Tomoaki Inoue
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Male ,Drug ,Time Factors ,Lithocholic acid ,Transcription, Genetic ,media_common.quotation_subject ,Cell Culture Techniques ,Pharmacology ,Biology ,Toxicology ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,In vivo ,Toxicity Tests ,medicine ,Animals ,Cluster Analysis ,Clofibrate ,RNA, Messenger ,Cells, Cultured ,Acetaminophen ,Oligonucleotide Array Sequence Analysis ,media_common ,Cisplatin ,Dose-Response Relationship, Drug ,Gene Expression Profiling ,Rats ,medicine.anatomical_structure ,chemistry ,Hepatocyte ,Disulfiram ,Toxicity ,Hepatocytes ,Feasibility Studies ,medicine.drug - Abstract
The study examined the feasibility of screening for hepatotoxicity by an in vitro gene expression analysis using rat primary hepatocytes and Affymetrix Rat Toxicology U34 arrays. Hepatocytes were exposed for 6 or 24 h to eight drugs, with different mechanisms of hepatotoxicity, at one third of the cytotoxic concentration TC50, i.e. acetaminophen, cyclophosphamide, clofibrate, chlorpromazine, lithocholic acid, cisplatin, diclofenac and disulfiram. The types of transcriptional changes observed in this study were generally consistent with previously reported in vivo data, although there were some differences. In hierarchical cluster analysis, drugs formed clusters depending on their mode of toxicity against cells. The number of transcripts affected by the cholestatic hepatotoxicants (lithocholic acid and chlorpromazine) or the drugs that rarely cause of hepatotoxicity (cisplatin, diclofenac and disulfiram) were limited compared with the other drugs (acetaminophen, clobifibrate and cyclophosphamide), where they did not induce transcriptional changes apparently related to toxicity. It is concluded that in vitro gene expression analysis of hepatocytes using microarray is a useful tool for evaluating the toxicological profile of drugs and in screening for the direct toxicity of drugs against hepatocytes.
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- 2008
8. Neuronal Necrosis in a Dog Following Exposure to an NMDA Receptor Antagonist
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Aisuke Nii, Ikuo Horii, and Norimitsu Shirai
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medicine.medical_specialty ,Dentate gyrus ,Glutamate receptor ,Hippocampus ,Anatomy ,AMPA receptor ,Biology ,Toxicology ,Entorhinal cortex ,Pathology and Forensic Medicine ,Endocrinology ,nervous system ,Internal medicine ,medicine ,NMDA receptor ,Long-term depression ,Ionotropic effect - Abstract
N-methyl-D-aspartate (NMDA) receptors constitute one of the three major classes of ionotropic glutamate receptors. We found neuronal necrosis in the brain of one out of four beagles exposed to an NMDA receptor antagonist. The lesions were characterized by shrunken cell bodies with intense cytoplasmic eosinophilia and pyknotic nuclei, and the affected cells were specifically positive for Fluoro-Jade B staining, which has great affinity for degenerating neurons. Bilaterally symmetrical lesions were observed primarily in the dentate gyrus, hippocampus, subiculum and entorhinal cortex. The present case suggests that NMDA receptor antagonism, possibly by altering synaptic transmission via receptors to glutamate within the affected regions, might lead to neuronal necrosis in the canine brain. Other possible pathogeneses include the encephalic ischemic condition associated with seizure activity.
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- 2008
9. Methodological validation of an existing telemetry system for QT evaluation in conscious guinea pigs
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Yoshimasa Hamada, Junko Abe, Takuma Harada, Motohiro Shiotani, and Ikuo Horii
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Male ,Pharmacology ,Validation study ,business.industry ,Safety pharmacology ,Guinea Pigs ,Sotalol ,Astemizole ,Recording system ,Toxicology ,QT interval ,Electrodes, Implanted ,Guinea pig ,Electrocardiography ,Long QT Syndrome ,Guinea pig heart ,Anesthesia ,Telemetry ,Models, Animal ,Animals ,Medicine ,business - Abstract
Introduction:Guinea pigs are suitable for in vivo QT assessment of newly discovered drugs at the pre-clinical stage because of the ease with which these animals can be handled, the lower amount of compound required for testing, and the similarity of the ion channels between the guinea pig heart and the human. Our purpose was to provide detailed methodological information on an existing telemetry recording system for use in evaluating QT interval prolongation in guinea pigs. Methods: Hartley guinea pigs weighing 400–700 g were used to investigate the appropriate configuration of electrodes to record defined T-waves and the influence of the surgical implantation of a transmitter on the QT interval, as well as to determine the appropriate formula for QT correction. In addition, the validity of using telemetry-monitored guinea pigs was tested by using compounds with (positive references) or without (vehicles) a QT-prolonging effect. Results: A lead with the negative pole placed between the scapulas and the positive pole positioned close to the sternum was found to be the most appropriate to obtain well-defined T-waves. The period for recovery from transmitter implantation was estimated to be at least 1 week. The best-fit formula for our telemetry guinea pig model was a modified Bazett's formula. QTc was prolonged significantly in guinea pigs given positive references, and the QTc was unaffected when the animals were given vehicles. Discussion: We believe that the information provided herein will be a quite helpful guide for researchers to evaluate the QT interval reliably and reproducibly in this telemetry guinea pig model.
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- 2007
10. CHANGES OF MICRO-RNA EXPRESSION IN RAT LIVER TREATED BY ACETAMINOPHEN OR CARBON TETRACHLORIDE − REGULATING ROLE OF MICRO-RNA FOR RNA EXPRESSION −
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Tamio Fukushima, Hiroshi Yamada, Yoshimasa Hamada, and Ikuo Horii
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Male ,Cell Survival ,Cell ,Pharmacology ,Biology ,Toxicology ,Cell Line ,RNA interference ,microRNA ,medicine ,Animals ,Carbon Tetrachloride ,Gene ,Acetaminophen ,Oligonucleotide Array Sequence Analysis ,Regulation of gene expression ,Reverse Transcriptase Polymerase Chain Reaction ,Microarray analysis techniques ,Rats, Inbred Strains ,Rats ,MicroRNAs ,medicine.anatomical_structure ,Gene Expression Regulation ,Liver ,Toxicity ,Hepatocytes ,medicine.drug - Abstract
Recently, microRNAs, involved in RNA interference, were discovered as a new gene regulation, with little is known in the filed of toxicology. In this study, a toxic dose of acetaminophen or carbon tetrachloride was administered singly to male rats, and microarry analysis using mirVanaTM miRNA bioarray was performed. Partial least squares-discriminant analysis of the microarray data revealed that microRNAs expression was specifically changed by treatments at 6 hr after dosing. Furthermore, we focused on miR298 and miR370 among the microRNAs commonly affected by hepatotoxicants, because they were speculated to regulate an oxidative stress-related gene. From real-time RT-PCR analysis, microRNAs expression was suppressed by hepatotoxicants at 6 and 24 hr. Regarding acetaminophen, the decreases were found even though there were no morphological changes in the liver at 6 hr. To investigate these 2 microRNAs in more detail, we measured their expression, WST-1 for mitochondrial function and LDH release for cell collapse in primary cultured hepatocytes exposed to several concentrations of acetaminophen for 3 hr. At more than 5 mM, the microRNA expression and WST-1 decreased, whereas LDH was unchanged. Therefore, the change in microRNA expression occurred at the time when mitochondrial function was damaged prior to cell collapse. From all the above findings, we conclude that microRNAs were affected by hepatotoxicants and that the changes were found in the early phase of toxicity. Thus, our data suggest microRNAs have an important role for toxicological mechanism and we proposed that the changes in microRNA expression might be key molecules for toxicity expression.
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- 2007
11. [Untitled]
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Ikuo Horii
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Pharmacology ,Pharmacokinetics ,Drug discovery ,Stage (cooking) - Published
- 2006
12. IN VIVO HEPATOTOXICITY STUDY OF RATS IN COMPARISON WITH IN VITRO HEPATOTOXICITY SCREENING SYSTEM
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Rie Kikkawa, Toshinori Yamamoto, Masaaki Fujikawa, Hiroshi Yamada, Ikuo Horii, and Yoshimasa Hamada
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Male ,Proteomics ,Kupffer Cells ,Amiodarone ,Pharmacology ,Biology ,Toxicology ,medicine.disease_cause ,In vivo ,Toxicity Tests ,medicine ,Animals ,Carbon Tetrachloride ,Cells, Cultured ,Acetaminophen ,Phospholipidosis ,Proteins ,Rats, Inbred Strains ,Tetracycline ,In vitro ,Rats ,Oxidative Stress ,Liver ,Cell culture ,Hepatocytes ,Toxicogenomics ,Biomarkers ,Oxidative stress ,medicine.drug - Abstract
For the establishment of a high throughput screening system using primary cell cultures, investigation of elucidated toxicities to assess the correlation between in vitro and in vivo hepatotoxicity is necessary in the safety evaluation of the compound. In the previous study, we reported the usability of rat primary cultured hepatocytes for establishment of high throughput screening system. To confirm the reliability of rat primary hepatocytes culture screening system, we conducted a single-dose in vivo study with relatively high dose of hepatotoxicant in rats using 4 reference compounds (acetaminophen, amiodarone, tetracycline, carbon tetrachloride), and investigated histopathological changes and expression of oxidative stress-related proteins by immunohistochemistry. We also carried out a proteomics analysis for estimating the reliable and sensitive biomarkers. Histopathologically, compound-specific hepatotoxicity was detected at 24 hr after administration in all compounds except amiodarone, which is known to induce phospholipidosis. Immunohistochemically, oxidative stress-related proteins were increased within 6 hr after administration in all treated groups. Proteomics analysis revealed several protein biomarkers related to oxidative stress and mitochondrial metabolism-regulation, which had been previously detected by proteomics analysis in in vitro screening system. Oxidative stress-related proteins were considered as useful biomarkers of hepatotoxicity; since they were detected by immunohistochemistry and proteomics analysis prior to appearance of compound-specific histopathological changes detected by light microscopy. Considering the relevance of in vitro system to in vivo system from the aspect of new biomarkers related to the toxicogenomics/toxicoproteomics, in vitro primary cell culture system would be sufficient to detect hepatotoxicity in the early stage of drug discovery.
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- 2006
13. INVESTIGATION OF PROTEOMIC BIOMARKERS IN IN VIVO HEPATOTOXICITY STUDY OF RAT LIVER: TOXICITY DIFFERENTIATION IN HEPATOTOXICANTS
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Rie Kikkawa, Hiroshi Yamada, Ikuo Horii, and Toshinori Yamamoto
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Male ,Proteomics ,Amiodarone ,Biology ,Toxicology ,medicine.disease_cause ,chemistry.chemical_compound ,In vivo ,Heat shock protein ,medicine ,Animals ,Carbon Tetrachloride ,Acetaminophen ,Gel electrophoresis ,Proteins ,Rats, Inbred Strains ,Tetracycline ,Rats ,Liver ,chemistry ,Biochemistry ,Toxicity ,Carbon tetrachloride ,HSP60 ,Biomarkers ,Oxidative stress ,medicine.drug - Abstract
We investigated the overall protein expression profiles in the in vivo hepatotoxicity of rats induced by four well-recognized hepatotoxicants. Acetaminophen (APAP), amiodarone (AMD), tetracycline (TC) and carbon tetrachloride (CTC) were administered to male rats by gavages and the liver at 24 hr post-dosing was applied to the proteomic experiment. Blood biochemistry and histopathology were examined to identify specific changes related to the compounds given. Protein expression in the liver was investigated by 2-dimensional gel electrophoresis (2DE), and spots showing a significantly different expression in treated versus control group were excised from gels and identified by Q-Tof mass spectrometer. They were well characterized based on their functions related to the mechanisms of toxicity of the compounds. Among them, we focused on the 8 proteins that were affected by all 4 compounds examined. Proteins related to oxidative stress response such as carbonic anhydrase III (CA3) and 60kDa heat shock protein (HSP60), and energy metabolism such as adenylate kinase 4 (AK4) were found. Moreover, hierarchical clustering analysis using 2D-gel spots information revealed the possibility to differentiate the groups based on their toxicity levels such as severity of liver damage. These results suggested that assessing the effects of hepatotoxicants on protein expression is worth trying to screen candidate compounds at the developmental stage of drugs.
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- 2006
14. Cisplatin-Induced Cytotoxicity in BSO-Exposed Renal Proximal Tubular Epithelial Cells: Sex, Age, and Species
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Akira Kawashima, Ikuo Horii, Yongke Lu, and Laifu Zhong
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Male ,Nephrology ,medicine.medical_specialty ,Cell Survival ,Urinary system ,Biology ,Critical Care and Intensive Care Medicine ,Kidney Tubules, Proximal ,Rats, Sprague-Dawley ,Andrology ,chemistry.chemical_compound ,Sex Factors ,Species Specificity ,Internal medicine ,medicine ,Animals ,Buthionine sulfoximine ,Viability assay ,Cytotoxicity ,Buthionine Sulfoximine ,Cells, Cultured ,Cisplatin ,Kidney ,Cell Death ,Epithelial Cells ,Haplorhini ,General Medicine ,Epithelium ,Rats ,Disease Models, Animal ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Female ,medicine.drug - Abstract
Cisplatin (CP)-induced kidney damage and effects of DL-buthionine-(S,R)-sulfoximine (BSO) on it are species- and age-different. It remains unclear whether CP-induced cytotoxicity in renal proximal tubular epithelial cells (RTEC), the main target cells of CP, is also species- and age-different; and whether CP-induced cytotoxicity varies with the difference in age and species, if any, is one of the questions. In the present study, the effects of BSO on CP-induced cytotoxicity in primary cultures of RTEC isolated from monkeys and different age and sex rats were studied.The RTEC were isolated from 3-week-old, 2-month-old, or 5-month-old rats, and 6-8 year-old monkeys. After subculturing, RTEC was inoculated into type I collagen-coated 96-well culture plates; after preincubation, 40 microM BSO was added, 16 hours later, varying concentrations of CP were added. At that time, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays were performed to test cell viability.The concentrations of CP that inhibited 50% cell growth (IC50) of RTEC from rats and monkeys were 1.11 and 3.03 mM at 8 hours, and 0.51 and 1.24 mM at 24 hours, respectively. The BSO made the IC50s of RTEC from rats and monkeys lower, down to 0.07 and 0.48 mM at 8 hours, and 0.02 and 0.11 mM at 24 hours, respectively. The IC50s of RTEC from different sex and age rats were almost same.These results suggested that CP-induced cytotoxicity was concentration- and time-dependent, with species-dependent differences, rat RTEC were more susceptible to CP than monkey RTEC, rat RTEC were more dependent on glutathione (GSH) during the stress state were than monkey cells; CP-induced cytotoxicity was without sex- and age-dependent differences in rat RTEC.
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- 2005
15. PRACTICAL APPLICATION OF GUINEA PIG TELEMETRY SYSTEM FOR QT EVALUATION
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Yasufusa Sawada, Junko Abe, Ikuo Horii, Yoshimasa Hamada, Motohiro Shiotani, Keitaro Hashimoto, and Takuma Harada
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Male ,Quinidine ,Nifedipine ,Pyridines ,Bepridil ,Guinea Pigs ,Thioridazine ,Pharmacology ,Toxicology ,QT interval ,Guinea pig ,Electrocardiography ,Pimozide ,Piperidines ,Haloperidol ,Animals ,Humans ,Telemetry ,Medicine ,Cisapride ,business.industry ,Reproducibility of Results ,Heart ,Disease Models, Animal ,Long QT Syndrome ,Injections, Intravenous ,Terfenadine ,business ,Anti-Arrhythmia Agents ,Antipsychotic Agents ,medicine.drug - Abstract
The purpose of this study was to evaluate a telemetry system for examining QT evaluation in the conscious free-moving guinea pig using 10 reference compounds whose effects on human QT interval are well established: 8 positive references (bepridil, terfenadine, cisapride, haloperidol, pimozide, quinidine, E-4031 and thioridazine), and 2 negative references (propranolol and nifedipine). Pharmacokinetic experiments were also performed for the 8 positive references. Telemetry transmitters were implanted subcutaneously in male Hartley guinea pigs, and the RR and QT intervals were measured. All 8 positive references prolonged QTc (QTc = k x QT/RR(1/2)) 10% or more during the 60 min observation period. When the values of the QTc changes were plotted against the serum concentrations, the resulting curves exhibited an anticlockwise hysteresis loop for all 8 references. In guinea pigs treated with haloperidol, changes of the T-wave shape from positive to flat were observed. The 2 negative references did not prolong the QTc. These findings suggest that the present telemetry guinea pig model is useful for QT evaluation in the early stages of drug development, because of the small body size of guinea pigs and their action potential configuration, which is similar to that of humans.
- Published
- 2005
16. PROTEIN EXPRESSION ANALYSIS OF RAT TESTES INDUCED TESTICULAR TOXICITY WITH SEVERAL REPRODUCTIVE TOXICANTS
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Hiroshi Yamada, Rie Kikkawa, Ikuo Horii, Tamio Fukushima, and Toshinori Yamamoto
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Male ,Proteomics ,Phosphatidylethanolamine Binding Protein ,Toxicology ,Rats, Sprague-Dawley ,Andrology ,chemistry.chemical_compound ,Heat shock protein ,Testis ,Animals ,Cyclophosphamide ,Glyceraldehyde 3-phosphate dehydrogenase ,Dose-Response Relationship, Drug ,biology ,Proteins ,Glutathione ,Molecular biology ,Rats ,Sulfasalazine ,Glutathione S-transferase ,chemistry ,Toxicity ,biology.protein ,Protein Expression Analysis ,Ethylene Glycols ,Reproductive toxicity - Abstract
The utilization of safety biomarkers to predict the possibility of compound-related toxicity provides several advantages for drug discovery and development, especially at an early stage. The objectives of this study were to investigate the effects of male reproductive toxicants on protein expression profiles in the rat testes and to identify potential biomarker candidates. Four well-known reproductive toxicants, ethylene glycol monomethyl ether (EGME), cyclophosphamide (CP), sulfasalazine (SASP) and 2,5-hexanedione (2,5-HD), were administered to male rats in a single dose, and protein expression profiles were investigated after 24 hr by two-dimensional gel electrophoresis (2DE). Histopathological examination of the testes and serum concentration analysis were also performed. From the results of the comparison of 2D-gels among different doses of a compound and among compounds, 52, 20, 24 and 111 spots were nominated as differentially expressed spots with EGME, CP, SASP and 2,5-HD treatments, respectively. Several spermatogenesis-involved proteins were identified, including glutathione S-transferase (GST), testis-specific heat shock protein 70-2 (HSP70-2), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and phosphatidylethanolamine-binding protein (PEBP). Some of them were altered by more than one compound. In summary, remarkable histopathological findings were observed only in the EGME high-dose group, and most of the protein changes were detected before histopathological changes occurred. Therefore, the proteins identified in this study could potentially serve as biomarkers to evaluate male reproductive toxicity at an early stage of drug discovery and development.
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- 2005
17. Effects of Sulfasalazine on Sperm Acrosome Reaction and Gene Expression in the Male Reproductive Organs of Rats
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Masashi Kato, Tamio Fukushima, Masatoshi Komiyama, Tetsuya Adachi, Ikuo Horii, Masao Horimoto, Chisato Mori, and Yoshimasa Hamada
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Male ,Infertility ,Blotting, Western ,Acrosome reaction ,Gene Expression ,Genitalia, Male ,Biology ,Toxicology ,Andrology ,medicine ,Animals ,RNA, Messenger ,Acrosome ,Sperm motility ,Oligonucleotide Array Sequence Analysis ,Membrane Glycoproteins ,Reverse Transcriptase Polymerase Chain Reaction ,Acrosome Reaction ,Gene Expression Profiling ,Anti-Inflammatory Agents, Non-Steroidal ,fungi ,Acrosomal membrane ,Epididymis ,medicine.disease ,Spermatozoa ,Molecular biology ,Sperm ,Rats ,Sulfasalazine ,Fertility ,medicine.anatomical_structure ,Sperm Motility ,Female ,Spermatogenesis - Abstract
Sulfasalazine (SASP) has been reported to depress the fertility in men and experimental male animals, but the fundamental mechanisms of infertility caused by SASP are still unknown. This study was designed to investigate the mechanisms of infertility in rats treated with SASP at a dose of 600 mg/kg for 28 days, including monitoring of sperm motility using computer associated sperm analysis system and acrosome reaction by FITC-concanavalin A lectin staining. The sperm motility and acrosome reaction, which are important for fertilization, were significantly reduced by SASP. Furthermore, to investigate the molecular mechanisms of infertility induced by SASP, mRNA expression analysis in the testes was performed using cDNA microarray as a first screening. It was revealed that CD59, which is located on the acrosomal membrane and is known to be important for the reproductive function of sperm, was affected in the testes; this was also confirmed by real-time PCR analysis, but the spermatogenesis-related genes examined in this study were not affected. Therefore, we focused on CD59 and two other acrosome membrane related-genes: MCP and DAF. CD59, MCP, and DAF in the epididymides of SASP-treated rats were significantly decreased as assessed by real-time RT-PCR analysis and additionally, the expression of CD59 protein was found to be decreased by Western blotting. These results allowed us to hypothesize that the suppression of epididymal acrosomal membrane proteins synthesis with their consequent reduced incorporation to the sperm membrane leads to a depressed sperm motility and acrosome reaction, and thereby leads to infertility in SASP treated male rats.
- Published
- 2004
18. Design and synthesis of the tumor-activated prodrug of dihydropyrimidine dehydrogenase (DPD) inhibitor, RO0094889 for combination therapy with capecitabine
- Author
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Tohru Ishikawa, Hideo Ishitsuka, Nobuhiro Oikawa, Kazuo Hattori, Hiroyuki Eda, Mika Endoh, Akira Kawashima, Masanori Miwa, Hiromi Tanimura, Yasunori Kohchi, Nobuo Shimma, Hitomi Suda, Ikuo Horii, and Masako Ura
- Subjects
Lung Neoplasms ,medicine.medical_treatment ,Clinical Biochemistry ,Administration, Oral ,Uterine Cervical Neoplasms ,Pharmaceutical Science ,Deoxycytidine ,Biochemistry ,Capecitabine ,Mice ,chemistry.chemical_compound ,Drug Stability ,Carcinoma, Non-Small-Cell Lung ,Cytidine Deaminase ,Antineoplastic Combined Chemotherapy Protocols ,Drug Discovery ,Dihydropyrimidine dehydrogenase ,medicine ,Animals ,Humans ,Prodrugs ,Tissue Distribution ,Thymidine phosphorylase ,Uracil ,Molecular Biology ,Dihydrouracil Dehydrogenase (NADP) ,chemistry.chemical_classification ,Thymidine Phosphorylase ,Chemotherapy ,Chemistry ,Organic Chemistry ,Esterases ,Cytidine deaminase ,Prodrug ,Xenograft Model Antitumor Assays ,Deoxyribonucleoside ,Enzyme ,Drug Design ,Cancer research ,Molecular Medicine ,Female ,Fluorouracil ,Oxidoreductases ,medicine.drug - Abstract
A series of tumor-activated prodrugs of the inhibitors of dihydropyrimidine dehydrogenase (DPD), an enzyme catabolizing 5-fluorouracil (5-FU: 4g), has been designed and synthesized. RO0094889 (11c) is a prodrug of 5-vinyluracil (4c), a known DPD inhibitor, and was designed to generate 4c selectively in tumor tissues by sequential conversion of 11c by three enzymes: esterase, cytidine deaminase and thymidine phosphorylase, the latter two of which are known to be highly expressed in various tumor tissues. When capecitabine (1), a tumor-activated prodrug of 5-FU, was co-administered orally with 11c, 5-FU in tumor tissues was significantly increased with only a slight increase of 5-FU in plasma as compared with oral capecitabine alone.
- Published
- 2003
19. Cassette Dosing Approach and Quantitative Structure−Pharmacokinetic Relationship Study of Antifungal N-Myristoyltransferase Inhibitors
- Author
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Kiyoshi Hasegawa, Tatsuo Ohtsuka, Yasuhiko Shiratori, Hidetoshi Shindoh, Ikuo Horii, Shigeyasu Ichihara, Yuko Aoki, and Nobuo Shimma
- Subjects
Male ,Octanol ,Multivariate statistics ,Antifungal Agents ,Quantitative Structure-Activity Relationship ,chemistry.chemical_compound ,Pharmacokinetics ,Linear regression ,Animals ,N-myristoyltransferase ,Computer Simulation ,Dosing ,Enzyme Inhibitors ,Benzofuran ,Benzofurans ,Chromatography ,General Chemistry ,Rats, Inbred F344 ,Rats ,Computer Science Applications ,Partition coefficient ,Models, Chemical ,Computational Theory and Mathematics ,chemistry ,Drug Design ,Acyltransferases ,Information Systems - Abstract
Pharmacokinetic (PK) parameters of N-myristoyltransferase (Nmt) inhibitors were measured, and a multivariate quantitative structure-pharmacokinetic relationship (QSPKR) model for predicting rat elimination half-life (t(1/2)) values was constructed. One hundred seven benzofuran derivatives have been selected as the data set for QSPKR analysis. The correlation between the t(1/2) values and 30 physicochemical descriptors was examined by a stepwise multiple linear regression method. The statistical analysis gives a significant QSPKR model (r = 0.843) with the following three variables: partial negative surface area (PNSA), atomic-based octanol/water partition coefficient (AlogP), and the number of rotational bonds (Rotlbonds). The QSPKR model obtained is predictive and simple, and would give a direction for designing new Nmt inhibitors having good PK profiles.
- Published
- 2002
20. Effects on fetal thymocyte populations and postnatal T-cell-dependent immune functions after maternal exposure to 5-fluorouracil during pregnancy in mice
- Author
-
Tomoaki Inoue and Ikuo Horii
- Subjects
medicine.medical_specialty ,Organogenesis ,T-Lymphocytes ,T cell ,Thymus Gland ,Biology ,Toxicology ,Mice ,Immune system ,Pregnancy ,Internal medicine ,medicine ,Animals ,Cytotoxic T cell ,Fetus ,Body Weight ,Organ Size ,Flow Cytometry ,medicine.disease ,Mixed lymphocyte reaction ,Mice, Inbred C57BL ,Thymocyte ,medicine.anatomical_structure ,Endocrinology ,Animals, Newborn ,Immune System ,Prenatal Exposure Delayed Effects ,Female ,Fluorouracil ,Immunosuppressive Agents ,CD8 - Abstract
5-Fluorouracil (5-FU) is a cytostatic anti-tumor drug which is known to have immunosuppressive activities. To assess the immunotoxic effects of 5-FU on fetal thymocyte populations and immune functions after birth, pregnant C57BL/6 mice were orally administered vehicle or 17 mg/kg/day of 5-FU during gestational days (GD) from 6 to 14. The fetal thymocyte populations were analyzed with flow cytometry (CD4/CD8 double staining), and immune functions (a mixed lymphocyte reaction, in vitro cytotoxic T-cell response, in vitro antibody-forming response) after birth were measured. Fetal thymus weight and thymocyte numbers were decreased by 5-FU administration. The decrease of the thymocytes was due mainly to the decrease of small CD4CD8 double positive (DP) thymocytes. The thymocyte numbers and populations recovered to the normal level 1 week after birth. The mixed lymphocyte response at the 6th week after birth tended to be slightly lower than the control levels, but the cytotoxic T-cell response and the antibody-forming response were the same as the control levels. These results suggest that immune functions might recover after birth, although maternal administration of 5-FU has a suppressive effect on fetal thymocyte maturation.
- Published
- 2002
21. DEVELOPMENT OF TELEMETRY SYSTEM IN THE COMMON MARMOSET - CARDIOVASCULAR EFFECTS OF ASTEMIZOLE AND NICARDIPINE
- Author
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Go Kito, Tatsuya Jikuzono, Kazuko Kobayashi, Taiji Hamada, Ikuo Horii, and Keitaro Hashimoto
- Subjects
Male ,Tachycardia ,Respiratory rate ,Nicardipine ,Torsades de pointes ,Toxicology ,QT interval ,Cardiovascular Physiological Phenomena ,Electrocardiography ,Anti-Allergic Agents ,Heart rate ,medicine ,Animals ,Telemetry ,Dose-Response Relationship, Drug ,business.industry ,Callithrix ,Astemizole ,Calcium Channel Blockers ,medicine.disease ,Circadian Rhythm ,Blood pressure ,Anesthesia ,medicine.symptom ,business ,medicine.drug - Abstract
The purpose of this study was to evaluate a telemetry system for examining the cardiovascular system in the conscious common marmoset. Parameters obtained were blood pressure, heart rate, respiratory rate, ECG, body temperature and locomotor activity, and these were continuously recorded on a data recorder via the telemetry system and then processed by a computerized system. Diurnal rhythms of blood pressure, heart rate, body temperature and locomotor activity were observed in this system. We studied the effects of astemizole (antihistamine) and nicardipine (Ca2+ channel blocker) on cardiovascular parameters. Astemizole at 30 mg/kg (p.o.) and at 1 to 3 mg/kg (i.v.), prolonged QT interval and induced ventricular extrasystole. Torsades de pointes occurred in one of three cases at 3 mg/kg (i.v.) and 30 mg/kg (p.o.), while it did not affect the blood pressure, respiratory rate and body temperature. Nicardipine at 30 mg/kg (p.o.) caused sustained hypotension and tachycardia. These results demonstrate the usefulness of the telemetry system using the common marmoset for evaluating the cardiovascular effects of drugs under physiological conditions.
- Published
- 2002
22. Synthesis and antifungal activities of novel 1,3-β- d -glucan synthase inhibitors. Part 1
- Author
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Takahide Watanabe, Toshikazu Yamazaki, Tomoaki Inoue, Yasuko Satoh, Kazuko Kobayashi, Kazunao Masubuchi, Takehiro Okada, Ikuo Horii, Eisaku Mizuguchi, Masahiro Aoki, Masahiro Sakaitani, Haruyoshi Shirai, Nobuo Shimma, Masami Kohchi, and Osamu Kondoh
- Subjects
Antifungal Agents ,Clinical Biochemistry ,Pharmaceutical Science ,Microbial Sensitivity Tests ,Biochemistry ,Chemical synthesis ,Microbiology ,Aspergillus fumigatus ,Inhibitory Concentration 50 ,Lactones ,Mice ,Structure-Activity Relationship ,chemistry.chemical_compound ,Candida albicans ,Drug Discovery ,medicine ,Animals ,Combinatorial Chemistry Techniques ,Enzyme Inhibitors ,Molecular Biology ,Inclusion Bodies ,Depsipeptide ,chemistry.chemical_classification ,biology ,Chemistry ,Organic Chemistry ,Candidiasis ,Membrane Proteins ,Ornithine ,medicine.disease ,biology.organism_classification ,Anti-Bacterial Agents ,Survival Rate ,Disease Models, Animal ,Enzyme ,Liver ,Therapeutic Equivalency ,Glucosyltransferases ,Enzyme inhibitor ,biology.protein ,Molecular Medicine ,Schizosaccharomyces pombe Proteins ,Systemic candidiasis ,Peptides - Abstract
Highly potent 1,3-β- d -glucan synthase inhibitors, 7b , 10a , 10b and 12 , have been identified by the chemical modification of the ornithine residue of a fungicidal macrocyclic lipopeptidolactone, RO-09-3655 ( 1 ), isolated from the cultured broth of Deuteromycotinia spp. These compounds showed stronger antifungal activity against systemic candidiasis as well as pulmonary aspergillosis in mice, and less hepatotoxicity as compared with 1 .
- Published
- 2001
23. [Untitled]
- Author
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Yukio Kato, Yuichi Sugiyama, Yuko Tsukamoto, Masako Ura, Ikuo Horii, Hideo Ishitsuka, and Hiroyuki Kusuhara
- Subjects
Pharmacology ,Chemistry ,Metabolite ,Organic Chemistry ,Pharmaceutical Science ,Prodrug ,In vitro ,Capecitabine ,chemistry.chemical_compound ,Pharmacokinetics ,Fluorouracil ,Oral administration ,Toxicity ,medicine ,Molecular Medicine ,Pharmacology (medical) ,Biotechnology ,medicine.drug - Abstract
Purpose. To identify the factors governing the dose-limiting toxicity in the gastrointestine (GI) and the antitumor activity after oral administration of capecitabine, a triple prodrug of 5-FU, in humans.
- Published
- 2001
24. Investigation of 5-FU disposition after oral administration of capecitabine, a triple-prodrug of 5-FU, using a physiologically based pharmacokinetic model in a human cancer xenograft model: comparison of the simulated 5-FU exposures in the tumour tissue between human and xenograft model
- Author
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Yukio Kato, Hideo Ishitsuka, Ikuo Horii, Yuko Tsukamoto, Yuichi Sugiyama, Masako Ura, and Tohru Ishikawa
- Subjects
Male ,Antimetabolites, Antineoplastic ,Physiologically based pharmacokinetic modelling ,Administration, Oral ,Mice, Nude ,Pharmaceutical Science ,Pharmacology ,Kidney ,Deoxycytidine ,Capecitabine ,Mice ,Cytosol ,Therapeutic index ,Pharmacokinetics ,Oral administration ,Tumor Cells, Cultured ,medicine ,Animals ,Humans ,Prodrugs ,Tissue Distribution ,Pharmacology (medical) ,Mice, Inbred BALB C ,Dose-Response Relationship, Drug ,business.industry ,General Medicine ,Prodrug ,Xenograft Model Antitumor Assays ,Effective dose (pharmacology) ,Therapeutic Equivalency ,Fluorouracil ,Area Under Curve ,Colonic Neoplasms ,business ,Neoplasm Transplantation ,Subcellular Fractions ,medicine.drug - Abstract
The nonlinear pharmacokinetics of capecitabine, a triple prodrug of 5-FU preferentially activated in tumour tissues, was investigated in human cancer xenograft models. A physiologically based pharmacokinetic (PBPK) model integrating the activation process of capecitabine to 5-FU and 5-FU elimination was constructed to describe the concentration/time profiles of capecitabine and its three metabolites, including 5-FU, in blood and organs. All the biochemical parameters (enzyme kinetic parameters, plasma protein binding and tissue binding of capecitabine and its metabolites) integrated in this model were measured in vitro. The simulated curves for the blood and tumour concentrations of capecitabine and its metabolites can basically describe the observed values. A simple prodrug of 5-FU, doxifluridine, is known to be activated to 5-FU to some extent in the gastrointestinal (GI) tract, causing diarrhoea, which is the dose limiting side effect of doxifluridine. Consequently, the therapeutic index (the ratio of 5-FU AUC in the tumour to that in GI) after the administration of effective dose capecitabine was predicted by this PBPK model and found to be five times and 3000 times greater than that of doxifluridine and 5-FU, respectively. This was compatible with the previous result for the difference in the ratio of the toxic dose to the minimum effective dose between capecitabine and doxifluridine, suggesting that 5-FU preferentially accumulates in tumour tissue after oral administration of capecitabine compared with the other drugs (doxifluridine and 5-FU). The 5-FU AUC in tumour tissue of human cancer xenograft models at the minimum effective dose was comparable with those estimated for humans at the clinical dose. In addition, the predicted therapeutic indices at the respective doses were correlated well between humans and mice (xenograft model). These results suggest that the 5-FU AUC in human tumour tissue at its clinically effective dose can be predicted based on the PBPK model inasmuch as the 5-FU AUC in a human cancer xenograft model at its effective dose may be measured or simulated. Copyright © 2001 John Wiley & Sons, Ltd.
- Published
- 2001
25. Pharmacokinetic Study of Capecitabine in Monkeys and Mice. Species Diffrences in Distribution of the Enzymes Responsible for its Activation to 5-FU
- Author
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Isami Kuruma, Hideko Onodera, Hideo Ishitsuka, and Ikuo Horii
- Subjects
Capecitabine ,Carboxylesterase ,Pharmacokinetics ,Chemistry ,Oral administration ,Pyrimidine-nucleoside phosphorylase ,medicine ,Cmax ,Distribution (pharmacology) ,Cytidine deaminase ,Pharmacology ,medicine.drug - Abstract
Capecitabine, a new orally available fluorpyrimidine carbamate, is converted to 5-fluorouracil (5-FU) by three sequential reactions involving the enzymes carboxylesterase, cytidine (Cyd) deaminase, and pyrimidine nucleoside phosphorylase (PyNPase). In the present study the plasma level profiles of capecitabine and its metabolites were investigated after single and repeated oral administration to monkeys and mice. The activities of the three enzymes were also determined in several tissues of humans, monkeys, mice, and rats. Capecitabine was absorbed rapidly and converted to 5-FU in both monkeys and mice after a single oral dosing. The concentration of the intact drug and 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouridine (5'-DFUR), and 5-FU were declined rapidly, as reflected by short half-lives of less than 1 hour in monkeys and 1-4 hours in mice. The AUCs of 5-FU were much lower than those of the intact drug and other metabolites, approximately 10 to 50-fold lower than that for 5'-DFUR expressed on a molar basis. In monkeys, the AUC and Cmax for capecitabine and its metabolites were dose related, and the AUC ratio for 5-FU to 5'-DFUR was independent of the dose. 5'-DFUR and the intact drug were prevalent in the plasma, and the 5'-DFCR level was slightly lower. In the monkey plasma, α-fluoro-β-alanine, a catabolite of 5-FU, was one of the main metabolites and showed relatively longer half-lives (5-7 hours). In mice, 5'-DFCR and the intact drug predominated in the plasma, and 5'-DFUR levels were lower than those. The AUCs of capecitabine, 5'-DFCR, and 5'-DFUR were dose related and similar in both genders during repeated daily oral dosing for 5 weeks in monkeys and mice. These values were not affected by repeated administration. The unique distribution of three 5-FU generating enzymes was found with interspecies deference. In humans, carboxylesterase was almost predominantly located in the liver. The monkey showed patterns of the enzyme activities that were the most similar to those in humans. In mice, the distribution patterns of carboxylesterase and Cyd deaminase were different from those in humans; however, mice have all three enzyme activities needed to generate 5-FU. On the contrary, in rats, extremely low Cyd deaminase activity was observed. The plasma level profiles of capecitabine and its metabolites were consistent with the observed activities of these enzymes in each species. Therefore, it seems that the monkey is the most suitable animal to use for predicting pharmacokinetics and safety of capecitabine in humans.
- Published
- 2000
26. Aromatic retinoid Ro 40-8757 reduces immunotoxicities of cyclophosphamide as revealed by immunohistochemical staining of lymphoid tissues and general pathologic examinations
- Author
-
Tomoaki Inoue and Ikuo Horii
- Subjects
Male ,Pathology ,medicine.medical_specialty ,Time Factors ,Combination therapy ,Cyclophosphamide ,Lymphoid Tissue ,medicine.drug_class ,Morpholines ,Lymphocyte ,Antineoplastic Agents ,Mice, Inbred Strains ,Spleen ,Thymus Gland ,Pharmacology ,Biology ,Toxicology ,Mice ,Retinoids ,chemistry.chemical_compound ,medicine ,Animals ,heterocyclic compounds ,Retinoid ,Body Weight ,Organ Size ,Immunohistochemistry ,Nitrogen mustard ,Lymphatic system ,medicine.anatomical_structure ,chemistry ,Antigens, Surface ,cardiovascular system ,Bone marrow ,Immunosuppressive Agents ,medicine.drug - Abstract
The aromatic retinoid (arotinoid) Ro 40-8757 (4-[2-[p-(E)-2-(5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-naphthyl) propenyl]phenoxy]ethyl]-morpholine), a compound with antitumor activities, has been studied in a combination therapy with the cytostatic antitumor drug cyclophosphamide (CPA), and was found to protect bone marrow from the toxic effects of CPA. To evaluate its protective effects against CPA toxicities on lymphoid systems, we treated BDF1 mice with Ro 40-8757 orally for 1 to 5 weeks in combination with CPA intraperitoneally. After the combination treatment, mice were subjected to immunohistochemical analysis with antibodies against cell surface markers (Thy 1.2, Lyt-2, L3T4, Kappa chain, and Ia) and, in addition, general pathologic examinations were done. The protective effects of Ro 40-8757 on CPA toxicities were observed. The lymphocyte reductions (both in T cells and B cells) in lymphoid organs by CPA were apparently less severe. In particular, recovery of immature T cells in the thymic cortex was greater in combination treatment with Ro 40-8757 and CPA than in treatment with CPA alone. From these results, it can be concluded that Ro 40-8757 protects the lymphoid organs (thymus, spleen, and lymph node) from the immunotoxicity of CPA, and the protective effect is evident, especially in the thymic cortical lymphocytes.
- Published
- 2000
27. Prolonged Effect of 5-Fluorouracil and Its Derivatives on Apoptosis Induction and Mitotic Inhibition in the Intestinal Epithelium of Male BDF1 Mice
- Author
-
Akira Inomata, Katsushi Suzuki, and Ikuo Horii
- Subjects
chemistry.chemical_classification ,medicine.medical_specialty ,Mitotic index ,Biology ,Toxicology ,Apoptosis induction ,Intestinal epithelium ,Pathology and Forensic Medicine ,Capecitabine ,Enzyme ,Endocrinology ,chemistry ,Apoptosis ,Fluorouracil ,Internal medicine ,medicine ,Mitosis ,medicine.drug - Abstract
The mechanisms of apoptosis induction and mitotic inhibition in the intestinal epithelium were investigated in male BDF1 mice treated with a single oral dose of 5-fluorouracil (5-FU). We measured the concentrations of 5-FU in the plasma and intestinal tissues and followed the detailed incidental time courses of both apoptotic index (AI) and mitotic index (MI) in the five intestinal compartments. Although the plasma concentration of 5-FU decreased to a value lower than the minimal effective concentration (MEC) within 8 hr after administration, the intestinal tissue concentrations remained remarkably higher than the MEC until 48 hr. 5-FU induced an increases of AI and decrease of MI for more than 48 hr with time courses that differed among the intestinal compartments. We also determined the AI and MI after administration of two 5-FU derivatives, 5'-DFUR and Capecitabine. The derivatives were administered orally at the equivalent dose of 5-FU; nevertheless the observed changes of AI and MI were far less significant than those for 5-FU. This finding may reflect the number of enzymatic activation steps each compound undergoes and explain why the toxicities of the 5-FU derivatives in the intestinal epithelium are less than that of 5-FU itself. The present study suggests that the prolonged effect of 5-FU would be due to retention of 5-FU within the intestinal epithelium, and that the different time courses for AI and MI in each intestinal compartment would depend on the stage that the cell-cycle was in when 5-FU uptake occurred.
- Published
- 1998
28. Microarray analysis of 6-mercaptopurine-induced-toxicity-related genes and microRNAs in the rat placenta
- Author
-
Takemi Yoshida, Kenji Taki, Ryota Ise, Ikuo Horii, and Tamio Fukushima
- Subjects
Antimetabolites, Antineoplastic ,Placenta ,Estrogen receptor ,Biology ,Toxicology ,Real-Time Polymerase Chain Reaction ,Pregnancy ,microRNA ,Progesterone receptor ,Gene expression ,medicine ,Animals ,RNA, Messenger ,Microarray analysis techniques ,Mercaptopurine ,Prolactin receptor ,Microarray Analysis ,Molecular biology ,Rats ,MicroRNAs ,medicine.anatomical_structure ,Gene Expression Regulation ,Cancer research ,Female ,Estrogen receptor alpha ,Immunosuppressive Agents - Abstract
MicroRNAs (miRNAs) are small single-stranded RNAs of 19-25 nucleotides and are important in posttranscriptional regulation of genes. Recently, the role of miRNAs in toxicity incidence is reported to be a regulator of key-stopper of gene expression, however the detailed mechanism of miRNAs is not well known yet. 6-Mercaptopurine (6-MP), the anti-leukemic and immunosuppressive drug, produced teratogenicity and pregnancy loss. We focused on the placenta to evaluate toxicity in embryo/fetal development produced by 6-MP treatment. MiRNA expression in the placenta was analyzed by miRNA microarray. Fifteen miRNAs were upregulated on GD13 and 5 miRNAs were downregulated on GD15 in 6-MP treatment rat placentas. Some miRNAs may have functions in apoptosis (miR-195, miR-21, miR-29c and miR-34a), inflammation (miR-146b), and ischemia (miR-144 and miR-451). In the maternal plasma, expression of miR-144 was significantly reduced by 6-MP treatment when examined by real-time RT-PCR. We determined toxicity-related gene expression in the rat placenta. Gene expression analysis was carried out by DNA oligo microarray using rat placenta total RNAs. Compared between predicted targets of miRNAs and microarray data in 6-MP-treated rat placenta, expressions of hormone receptor genes (estrogen receptor 1; Esr1, progesterone receptor; Pgr, and prolactin receptor; Prlr), xanthine oxidase (Xdh), Slc38a5 and Phlda2 genes were changed. The histopathologically found increase in trophoblastic giant cells and reduced placental growth by 6-MP treatment were well correlated to these gene expressions. These data suggest that some miRNAs may link to toxicological reactions in 6-MP-induced placental toxicity.
- Published
- 2013
29. Mice Lacking p27 Display Increased Body Size, Multiple Organ Hyperplasia, Retinal Dysplasia, and Pituitary Tumors
- Author
-
Noriko Ishida, Akira Inomata, Nobuyuki Shishido, Keiko Nakayama, Tomoaki Inoue, Keiichi I. Nakayama, Michiko Shirane, Dennis Y. Loh, and Ikuo Horii
- Subjects
medicine.medical_specialty ,Pituitary tumors ,Gene targeting ,Contact inhibition ,Cell cycle ,Hyperplasia ,Biology ,medicine.disease ,Embryonic stem cell ,General Biochemistry, Genetics and Molecular Biology ,Endocrinology ,Internal medicine ,medicine ,Retinal dysplasia ,CDKN1B - Abstract
Mice lacking p27 Kip1 have been created by gene targeting in embryonic stem cells. These mice are larger than the control animals, with thymus, pituitary, and adrenal glands and gonadal organs exhibiting striking enlargement. CDK2 activity is elevated about 10-fold in p27 −/− thymocytes. Development of ovarian follicles seems to be impaired, resulting in female sterility. Similar to mice with the Rb mutation, the p27 −/− mice often develop pituitary tumors spontaneously. The retinas of the mutant mice show a disturbed organization of the normal cellular layer pattern. These findings indicate that p27 Kip1 acts to regulate the growth of a variety of cells. Unexpectedly, the cell cycle arrest mediated by TGFβ, rapamycin, or contact inhibition remained intact in p27 −/− cells, suggesting that p27 Kip1 is not required in these pathways.
- Published
- 1996
30. Future prospects for toxicokinetics: its ability to predict drug adverse events in humans
- Author
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Mitsuhiro Tsuda, Ikuo Horii, Yuichi Sugiyama, and Kiyomi Ito
- Subjects
Drug ,Drug-Related Side Effects and Adverse Reactions ,business.industry ,media_common.quotation_subject ,Pharmacology ,Toxicology ,Bioinformatics ,Risk Assessment ,Predictive Value of Tests ,Toxicity Tests ,Animals ,Humans ,Toxicokinetics ,Medicine ,Pharmacokinetics ,Adverse effect ,business ,media_common - Published
- 1996
31. The dithiane Ro 44-5912 enhances vinblastine sensitivity of drug resistant and parental KB lines in vivo
- Author
-
Ikuo Horii, C. Konishi, K. Kobayashi, J.F. Eliason, R. Sawada, Shigeyasu Ichihara, Isami Kuruma, T. Tsukaguchi, and H. Ramuz
- Subjects
Male ,Cancer Research ,Vasodilator Agents ,Transplantation, Heterologous ,Antineoplastic Agents ,Cyclosporins ,Drug resistance ,Biology ,Pharmacology ,Vinblastine ,KB Cells ,Mice ,Pharmacokinetics ,In vivo ,Cyclosporin a ,medicine ,Animals ,Humans ,Mice, Inbred BALB C ,Propylamines ,Calcium Channel Blockers ,Drug Resistance, Multiple ,Acute toxicity ,Multiple drug resistance ,Oncology ,Drug Resistance, Neoplasm ,Toxicity ,Female ,Drug Screening Assays, Antitumor ,medicine.drug - Abstract
The multidrug resistance modifying activity of a dithiane analogue of tiapamil, Ro 44-5912, was examined in vivo . Results of acute toxicity studies in mice indicated that lethal toxicity occurred with doses greater than 1 mmol/kg of body weight. In a preliminary pharmacokinetic investigation, Ro 44-5912 appeared to have a longer half-life in mice than did its (R) enantiomer Ro 44-5911 (3.15 ± 0.02 h versus 2.15 ± 0.14 h) as measured by total radiolabel in plasma. In non-tumour bearing mice, Ro 44-5912 enhanced the toxicity of vinblastine in a manner that was dependent on the dose of both drugs. Vinblastine did not have a significant effect on tumour growth when given to nude mice bearing the parental cell line KB-3-1 at a dose of 1.5 mg/kg once per week for 3 weeks. Combination treatment with Ro 44-5912 markedly enhanced the antitumour activity of vinblastine. Similar results were seen when KB-3-1 tumours were treated with the combination of vinblastine plus cyclosporin A. Another tiapamil analogue, Ro 11-2933, had no enhancing activity with this tumour when used at an equitoxic combination dose. Ro 44-5912 also significantly enhanced vinblastine activity with P-glycoprotein-expressing KB-8-5 tumours. In three independent experiments, Ro 44-5912 enhanced the growth inhibiting activity of vinblastine by a mean of approximately 40%. Neither Ro-11-2933 nor cyclosporin A, at the maximal tolerated doses in combination with vinblastine, led to significant inhibition of KB-8-5 tumour growth compared to treatment with the two vehicles alone. These results show that Ro 44-5912 is an active modulator of drug resistance in vivo .
- Published
- 1995
32. Flow Cytometric Analysis for the Evaluation of the Rat Sperm Viability and Number in the Male Reproductive Toxicity Studies
- Author
-
Chiaki Katoh, Nobuko Fukatsu, Setsuko Takizawa, and Ikuo Horii
- Subjects
endocrine system ,Embryology ,medicine.diagnostic_test ,urogenital system ,Motility ,General Medicine ,Biology ,Epididymis ,Negative stain ,Sperm ,Staining ,Flow cytometry ,Andrology ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Pediatrics, Perinatology and Child Health ,Immunology ,medicine ,Propidium iodide ,Reproductive toxicity ,reproductive and urinary physiology ,Developmental Biology - Abstract
We investigated the application of flow cytometric analysis to evaluate the rat sperm viability and number in the male reproductive toxicity studies. Flow cytometric procedure has been developed to evaluate sperm number and viability that uses fluorescent dye (propidium iodide, PI) to distinguish between viable (negative staining) and dead (positive staining) sperm. Sperm samples were collected from the caudal epididymides of SD rats (13–21 weeks old). PI staining patterns/viabilities were compared among several ranges of sperm concentrations, and several kinds of sperm viability. Viabilities determined by flow cytometry (FC) were also compared with motility by direct microscopical observation in several kinds of sperm viability. No notable changes in the PI staining patterns/viabilities were observed in the range from 1 × 105 to 6 × 106 sperm/ml. Essentially similar results were obtained from both FC and microscopical analyses for three degrees of viability sperm: live sperm (general preparation as a control), weakly viable sperm (mixed by vortex mixer for 30 seconds), and dead sperm (treated with 90°C or Triton X-100). Viabilities of normal rat samples were 95.0 ± 4.0% in FC and 93.7 ± 4.6% in microscopical observation, indicating good correlation in both analyses. Sperm numbers with FC analysis were approximately 0.8 × 106 to 1.8 × 106 sperm per mg indicating good correlation with those by microscopy. It was concluded that the present flow cytometric procedure was objective, rapid and reliable, and that it was one of the useful methods for measuring the number and evaluating the viability of sperm collected from the caudal epididymides of rats in the male reproductive toxicity studies.
- Published
- 1995
33. Male fertility in rats treated with etretinate for 4 weeks
- Author
-
Kenichi Shimura, Setsuko Takizawa, Izuru Imamura, Mariko Hayashi, Nobuko Fukatsu, and Ikuo Horii
- Subjects
Male ,Vitamin ,medicine.medical_specialty ,media_common.quotation_subject ,Longevity ,Physiology ,Etretinate ,Fertility ,Biology ,Toxicology ,Drug Administration Schedule ,Rats, Sprague-Dawley ,Eating ,chemistry.chemical_compound ,Keratolytic Agents ,Pregnancy ,Internal medicine ,Testis ,medicine ,Animals ,media_common ,Dose-Response Relationship, Drug ,Sperm Count ,Body Weight ,Organ Size ,Epididymis ,Spermatozoa ,Sperm ,Hormones ,Rats ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Toxicity ,Sperm Head ,Female ,Histopathology ,Spermatogenesis ,medicine.drug - Abstract
The toxicity of Etretinate, a retinoid compound, on the male reproductive system was studied in male rats. The drug was administered for four weeks at the dose levels of 0 (control : Vehicle, Peanut oil), 5 and 25 mg/kg/day. The animals were then allowed to mate, and their male reproductive functions and organs were examined in detail. No significant changes due to toxicity were observed in male reproductive functions and organs in the 5 mg/kg/day group after the 4-week treatment. In contrast, males in the 25 mg/kg/day group showed drug-related changes in their reproductive performance (decrease of mating ability and fertility rate), testosterone blood level, sperm head counts, sperm Viability and number in the caudal epididymis, organ weight and in the histopathology of their reproductive organs (atrophy of seminiferous tubules, necrosis of spermatocytes and spermatids, vacuolation of nuclei of spermatocytes and spermatids). Even though Etretinate belong to the retinoid group of compounds, the changes seen in the 25 mg/kg/day group were almost the same as those observed in Vitamin A-deficient animals. In conclusion, there is a correlation between changes due to toxicity observed for parameters of male fertility and for histopathological evaluation of the testis of rats that receiving high dose, treatment with Etretinate for 4 weeks.
- Published
- 1995
34. 6-Mercaptopurine-induced histopathological changes and xanthine oxidase expression in rat placenta
- Author
-
Tamio Fukushima, Takemi Yoshida, Ryota Ise, Ikuo Horii, and Kenji Taki
- Subjects
Xanthine Oxidase ,Placenta ,Apoptosis ,Peptide hormone ,Toxicology ,Endometrium ,Real-Time Polymerase Chain Reaction ,Andrology ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Pregnancy ,medicine ,Animals ,Xanthine oxidase ,Fetal Death ,reproductive and urinary physiology ,Fetus ,Caspase 3 ,Mercaptopurine ,Gene Expression Regulation, Developmental ,Embryo ,Organ Size ,Rats ,medicine.anatomical_structure ,chemistry ,Biochemistry ,Giant cell ,embryonic structures ,Gestation ,Female - Abstract
The placenta secures the embryo and fetus to the endometrium and releases a variety of steroid and peptide hormones that convert the physiology of a female to that of a pregnant female. Chemical-induced alteration or deviation of placental function in the maternal and extraembryonic tissue can ultimately lead to pregnancy loss, congenital malformation and fetal death. The 6-mercaptopurine (6-MP), an anti-leukemic drug, is known to produce undesired effects on some organs, then the placenta/embryo toxicity of 6-MP was investigated in pregnant rats given 60 mg/kg with two intraperitoneal injections on gestation days (GD) 11 and 12. The rats were sacrificed and their placentas were collected on GD13 or 15. On GD15 small and limb-defected embryos were found in the 6-MP-treated rats. Placental weights were significantly reduced on GD15, as well as a reduced number of cells was detected in the labyrinth zone with both the labyrinth and basal zones having thinned. Cleaved caspase-3-positive cells increased in number in the labyrinth zone, while in the basal zone, glycogen cells reduced with cytolysis. The number of spongiotrophoblasts and trophoblastic giant cells also increased by 6-MP treatment. The 6-MP-treatment resulted in the increased xanthine oxidase (Xdh) expression in the placenta, which gene is related to the ischemic condition of tissues. These data suggest that apoptosis of the labyrinth zone cells may lead to decreased materno-fetal exchange. Moreover, subsequent ischemia in the placental tissue may occur and induce Xdh expression.
- Published
- 2012
35. AP2 adaptor complex mediates bile salt export pump internalization and modulates its hepatocanalicular expression and transport function
- Author
-
Tamio Fukushima, Yuichi Sugiyama, Sotaro Naoi, Kensuke Aida, Reiko Horikawa, Asami Hattori, Hironori Nagasaka, Ikuo Horii, Takashi Yabuki, Hisamitsu Hayashi, Kaori Inamura, and Tomozumi Takatani
- Subjects
Male ,media_common.quotation_subject ,Adaptor Protein Complex 2 ,Endocytosis ,Phenylbutyrate ,Rats, Sprague-Dawley ,Adaptor Protein Complex alpha Subunits ,Cholestasis ,Ubiquitin ,medicine ,Animals ,Humans ,Tyrosine ,Internalization ,ATP Binding Cassette Transporter, Subfamily B, Member 11 ,media_common ,Hepatology ,biology ,Bile Canaliculi ,Ubiquitination ,food and beverages ,Cell Polarity ,Biological Transport ,medicine.disease ,Bile Salt Export Pump ,Phenylbutyrates ,Cell biology ,Rats ,Cytosol ,Biochemistry ,biology.protein ,ATP-Binding Cassette Transporters ,HeLa Cells - Abstract
The bile salt export pump (BSEP) mediates the biliary excretion of bile salts and its dysfunction induces intrahepatic cholestasis. Reduced canalicular expression of BSEP resulting from the promotion of its internalization is one of the causes of this disease state. However, the molecular mechanism underlying BSEP internalization from the canalicular membrane (CM) remains unknown. We have shown previously that 4-phenylbutyrate (4PBA), a drug used for ornithine transcarbamylase deficiency (OTCD), inhibited internalization and subsequent degradation of cell-surface-resident BSEP. The current study found that 4PBA treatment decreased significantly the expression of α- and μ2-adaptin, both of which are subunits of the AP2 adaptor complex (AP2) that mediates clathrin-dependent endocytosis, in liver specimens from rats and patients with OTCD, and that BSEP has potential AP2 recognition motifs in its cytosolic region. Based on this, the role of AP2 in BSEP internalization was explored further. In vitro analysis with 3×FLAG-human BSEP-expressing HeLa cells and human sandwich-culture hepatocytes indicates that the impairment of AP2 function by RNA interference targeting of α-adaptin inhibits BSEP internalization from the plasma membrane and increases its cell-surface expression and transport function. Studies using immunostaining, coimmunoprecipitation, glutathione S-transferase pulldown assay, and time-lapse imaging show that AP2 interacts with BSEP at the CM through a tyrosine motif at the carboxyl terminus of BSEP and mediates BSEP internalization from the CM of hepatocytes. Conclusion: AP2 mediates the internalization and subsequent degradation of CM-resident BSEP through direct interaction with BSEP and thereby modulates the canalicular expression and transport function of BSEP. This information should be useful for understanding the pathogenesis of severe liver diseases associated with intrahepatic cholestasis. (HEPATOLOGY 2012;55:1889–1900)
- Published
- 2012
36. The anti-tumor arotinoid RO 40-8757 protects bone marrow from the toxic effects of 5-fluorouracil
- Author
-
Tomoaki Inoue, Diethelm Hartmann, James F. Eliason, Akiko Kubota, and Ikuo Horii
- Subjects
Cancer Research ,medicine.medical_specialty ,Combination therapy ,Morpholines ,medicine.medical_treatment ,Antineoplastic Agents ,Pharmacology ,Rats, Sprague-Dawley ,Retinoids ,Bone Marrow ,Internal medicine ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Animals ,Progenitor cell ,Chemotherapy ,business.industry ,Mammary Neoplasms, Experimental ,Hematopoietic Stem Cells ,In vitro ,Rats ,Haematopoiesis ,medicine.anatomical_structure ,Endocrinology ,Oncology ,Fluorouracil ,Toxicity ,Female ,Bone marrow ,business ,medicine.drug - Abstract
Combination therapy with 5-Fluorouracil (5-FU) and the arotinoid Ro 40-8757 (mofarotene) of established chemically induced mammary tumors in rats was examined. The cytotoxic drug was administered weekly and Ro 40-8757 was given daily. The dose of Ro 40-8757 used in this study did not have an effect on tumor burden but, in combination with 5-FU, significantly enhanced the reduction in tumor burden and tumor number. In order to determine if Ro 40-8757 had a protective effect on 5-FU-treated animals, several studies were performed with non-tumor-bearing mice. The 5-FU was given once a week for 3 weeks at a dose that was lethal only after the third administration. When this treatment was combined with Ro 40-8757 given 5 times/week, approximately 50% of the mice survived. Examination of the progenitor cell contents of femura and spleens of treated mice indicated that the protective effect of Ro 40-8757 was manifested at the primitive hemopoietic progenitor cell level. Studies with murine bone marrow cells and human breast-cancer cell lines in vitro demonstrated that there was no interaction between the 2 drugs at the cellular level, indicating that the arotinoid does not enhance the ability of cells to metabolize 5-FU. This protective effect of the arotinoid makes it a useful potential partner for combination therapy with 5-FU. © 1994 Wiley-Liss, Inc.
- Published
- 1994
37. EFFECT OF ETRETINATE (AROMATIC RETINOID) TREATMENT DURING GESTATION AND LACTATION PERIODS ON VIABILITY AND SOMATIC GROWTH IN F1 RATS
- Author
-
Setsuko Takizawa, Nobuko Fukatsu, Ikuo Horii, and Toshiko Fujii
- Subjects
Male ,medicine.medical_specialty ,Etretinate ,Growth ,Gestation period ,Biology ,Toxicology ,Rats, Sprague-Dawley ,Pregnancy ,Lactation ,Internal medicine ,medicine ,Animals ,Insulin-Like Growth Factor I ,Fetal Viability ,Organ Size ,Teratology ,Rats ,medicine.anatomical_structure ,Endocrinology ,Liver ,Growth Hormone ,Pituitary Gland ,Toxicity ,Pregnancy, Animal ,Gestation ,Female ,Breast feeding ,medicine.drug ,Hormone - Abstract
When female SD rats were continuously treated with Etretinate throughout pre-mating, gestation, and lactation periods, the resulting F1 pups exhibited low viability and inhibition of somatic growth after birth (Hummler et al., 1981). Nevertheless, these pups showed no notable change in body weight and external appearance at birth. We used the cross-fostering (between control and treated groups) method and investigate the neonatal viability and the growth hormonal changes in order to assess which treatment period of gestation or lactation was mainly involved in these effects and what changes were actually induced in the F1 pups. The results showed that low viability and inhibition of somatic growth after birth were mainly related to treatment during the gestation period, and these effects were augmented by treatment during the lactation period. Serum GH and IGF-I levels were increased on day 21 in F1 pups groups in which inhibition of somatic growth was observed. These results indicated that treatment with Etretinate during the gestation period might induce a decrease in the number of receptors of GH and IGF-I or other changes, such as a poor-response in target tissues due to a down-regulation, with an increase of serum GH and IGF-I levels.
- Published
- 1994
38. The anti-tumor arotinoid RO 40-8757 protects bone marrow from the toxic effects of cyclophosphamide
- Author
-
Tomoaki Inoue, James F. Eliason, D. Hartmann, A. Kubota, Ikuo Horii, and Teelmann K
- Subjects
Cancer Research ,Pathology ,medicine.medical_specialty ,Combination therapy ,Cyclophosphamide ,9,10-Dimethyl-1,2-benzanthracene ,Morpholines ,medicine.medical_treatment ,Antineoplastic Agents ,Pharmacology ,Rats, Sprague-Dawley ,Retinoids ,Bone Marrow ,medicine ,Animals ,Drug Interactions ,Clonogenic assay ,Chemotherapy ,business.industry ,Body Weight ,Mammary Neoplasms, Experimental ,Hematopoietic Stem Cells ,Hematopoiesis ,Rats ,Haematopoiesis ,medicine.anatomical_structure ,Oncology ,Erythropoietin ,Toxicity ,Female ,Bone marrow ,business ,medicine.drug - Abstract
The arotinoid Ro 40-8757 is a novel compound that has significant therapeutic activity against chemically induced breast tumors in rats. The results of combination therapy with cyclophosphamide, plus the arotinoid showed that the anti-tumor effects were additive. However, all of the rats given CPA alone died between week 6 and week 10 of treatment. None of the animals in the group treated with the combination died. Administration of a single dose of Ro 40-8757 to non-tumor bearing mice resulted in a transient increase in bone-marrow-progenitor cells after 2 days and a decrease in splenic progenitors at day 4. Treatment of mice with the combination demonstrated that the marrow progenitors were protected from the toxic effects of CPA by the arotinoid. Direct addition of Ro 40-8757 to mouse bone-marrow cells in clonogenic assay cultures containing WEHI-3-conditioned medium plus erythropoietin showed no significant enhancement by the arotinoid. The results suggest that this compound may exert its protective effect through the hemopoietic micro-environment.
- Published
- 1993
39. Toxicokinetics: Its significance and practical problems
- Author
-
Thomas B. Marriott, Ryuichi Kato, Fumio Sagami, Ikuo Horii, David E. Case, Hiroshi Mayahara, Hideo Hakusui, Toshiji Igarashi, Kosei Noda, and Mitchell N. Cayen
- Subjects
Gerontology ,Drug Industry ,business.industry ,Toxicology ,United States ,Rats ,Mice ,Dogs ,Japan ,Animals ,Humans ,Medicine ,Toxicokinetics ,Pharmacokinetics ,business - Published
- 1993
40. Toxic effect onset and evaluations of medicinal drugs--horizon for Darwinian toxicological thought
- Author
-
Ikuo Horii
- Subjects
Drug-Related Side Effects and Adverse Reactions ,Evolutionary medicine ,Environmental ethics ,Hominidae ,Biological evolution ,Pharmacology ,Biology ,Toxicology ,Living body ,Biological Evolution ,humanities ,Xenobiotics ,Evolution, Molecular ,Animals ,Humans ,Darwinism ,Meaning (existential) ,Adverse effect ,Evolutionary theory - Abstract
The theory of Darwinian Medicine linked to an extension of Darwin's evolutionary theory is based on the approach from the aspect of "why we become ill?".This theory enables us to understand the relationship between humans and diseases by thinking from evolutional perspective, shows an important help for preventive medicine, and is meaningful to consider the future human healthcare. Toxicology has been defined as a research of adverse effect of xenobiotic substances backed up by diverse-sciences. Toxic effects are basically responses to xenobiotic substances, and expressed as triggering or additional accelerating adverse effects toward abnormal condition. Toxic effects, biological adverse responses, are interpreted as protective responses of living body, and the adverse effects caused by drugs are also considered to be protective responses. This logic can be translated as "Darwinian Toxicology" corresponding to "Darwinian Medicine", replying to "why we get into toxic condition by xenobiotics exposure". This paper refers to the meaning of toxic effects based on mechanisms underlying and comprehensive drug safety evaluation from Darwinian Medicine perspectives.
- Published
- 2010
41. ChemInform Abstract: Discovery and Development of Novel Anticancer Drug Capecitabine
- Author
-
Hideo Ishitsuka, Ikuo Horii, and Nobuo Shimma
- Subjects
chemistry.chemical_classification ,Cyclophosphamide ,Chemistry ,Metabolite ,General Medicine ,Cytidine deaminase ,Pharmacology ,Bioavailability ,Capecitabine ,Carboxylesterase ,chemistry.chemical_compound ,Enzyme ,medicine ,Thymidine phosphorylase ,medicine.drug - Abstract
Capecitabine (N4-pentyloxycarbonyl-5'-deoxy-5-fluorocytidine) is a novel oral fluoropyrimidine carbamate, which was designed to be sequentially converted to 5-fluorouracil (5-FU) by three enzymes located in the liver and in tumors. N4-alkoxycarbonyl-5'-deoxy-5-fluorocytidine derivatives including capecitabine pass intact through the intestinal tract and are sequentially converted to 5-FU by a cascade of the three enzymes. The first step is the conversion to 5'-deoxy-5-fluorocytidine (5'-DFCR) by carboxylesterase located in the liver, then to 5'-deoxy-5-fluorouridine (5'-DFUR) by cytidine deaminase highly expressed in the liver and various solid tumors, and finally to 5-FU by thymidine phosphorylase (dThdPase) preferentially located in tumor tissues. Among large numbers of the derivatives, capecitabine was selected based on its susceptibility to hepatic carboxylesterase, oral bioavailability in monkeys and efficacy in a human cancer xenograft. Capecitabine given orally yielded substantially higher concentrations of 5-FU within tumors than in plasma or normal tissue (muscle). The tumor 5-FU levels were also much higher than those achieved by intraperitoneal administration of 5-FU at equi-toxic doses. This tumor selective delivery of 5-FU ensured greater efficacy and a more favourable safety profile than with other fluoropyrimidines. In 24 human cancer xenograft models studied, capecitabine was more effective at a wider dose range and had a broader spectrum of antitumor activity than 5-FU, UFT or its intermediate metabolite 5'-DFUR. The susceptibility of the xenografts to capecitabine correlated with tumor dThdPase levels. Moreover, the conversion of 5'-DFUR to 5-FU by dThdPase in tumor was insufficient in a xenograft model refractory to capecitabine. In addition, the efficacy of capecitabine was enhanced by dThdPase up-regulators, such as by taxanes and cyclophosphamide and by X-ray irradiation. The efficacy of capecitabine may, therefore, be optimized by selecting the most appropriate patient population based on dThdPase status and/or by combining it with dThdPase up-regulators. Capecitabine has additional characteristics not found with 5-FU, such as potent antimetastatic and anticachectic actions in mouse tumor models. With these profiles, capecitabine may have substantial potential in cancer treatment.
- Published
- 2010
42. ChemInform Abstract: Cassette Dosing Approach and Quantitative Structure-Pharmacokinetic Relationship Study of Antifungal N-Myristoyltransferase Inhibitors
- Author
-
Kiyoshi Hasegawa, Shigeyasu Ichihara, Yasuhiko Shiratori, Nobuo Shimma, Yuko Aoki, Hidetoshi Shindoh, Tatsuo Ohtsuka, and Ikuo Horii
- Subjects
Partition coefficient ,Octanol ,Multivariate statistics ,chemistry.chemical_compound ,Chromatography ,Pharmacokinetics ,Chemistry ,Linear regression ,N-myristoyltransferase ,General Medicine ,Dosing ,Benzofuran - Abstract
Pharmacokinetic (PK) parameters of N-myristoyltransferase (Nmt) inhibitors were measured, and a multivariate quantitative structure−pharmacokinetic relationship (QSPKR) model for predicting rat elimination half-life (t1/2) values was constructed. One hundred seven benzofuran derivatives have been selected as the data set for QSPKR analysis. The correlation between the t1/2 values and 30 physicochemical descriptors was examined by a stepwise multiple linear regression method. The statistical analysis gives a significant QSPKR model (r = 0.843) with the following three variables: partial negative surface area (PNSA), atomic-based octanol/water partition coefficient (AlogP), and the number of rotational bonds (Rotlbonds). The QSPKR model obtained is predictive and simple, and would give a direction for designing new Nmt inhibitors having good PK profiles.
- Published
- 2010
43. Detection of an endothelin-1-binding protein complex by low temperature SDS-PAGE
- Author
-
Yasuhiro Furuichi, Ikuo Horii, Tsuyoshi Takasuka, and Takahide Watanabe
- Subjects
Guinea Pigs ,Biophysics ,Receptors, Cell Surface ,Plasma protein binding ,Biochemistry ,Ribosome ,Iodine Radioisotopes ,Mice ,Dogs ,Pregnancy ,Microsomes ,Protein purification ,Animals ,Humans ,Molecular Biology ,Polyacrylamide gel electrophoresis ,Gel electrophoresis ,Chromatography ,Receptors, Endothelin ,Chemistry ,Endothelins ,Binding protein ,Cholic Acids ,Cell Biology ,Endothelin 1 ,Molecular Weight ,Kinetics ,Electrophoresis ,Organ Specificity ,Autoradiography ,Electrophoresis, Polyacrylamide Gel ,Female ,Protein Binding - Abstract
We found that the complex of ET-1 and its binding protein was stable enough to be separated by SDS-PAGE when electrophoresis was run at a low temperature. Cross-linking was not necessary for the detection of [125I]-ET-1 and its binding protein complex by autoradiography. This simple method could be used in qualitative (estimation of apparent molecular weight of ET-1 binding protein) and quantitative (determination of relative content of ET-binding protein) analysis of the ET-binding protein complex. ET-binding protein complexes of various animal species and organs were investigated by this method.
- Published
- 1991
44. Utilization of anin vitro Hepatotoxicity Test in the Early Stage of Drug Discovery
- Author
-
Hiroshi Yamada, Toshinori Yamamoto, Tamio Fukushima, Kaori Tomizawa, Ikuo Horii, and Rie Kikkawa
- Subjects
Molecular targeting ,Drug discovery ,Pharmacology ,Biology ,Stage (cooking) ,In vitro - Published
- 2008
45. Integrated NMR-based metabonomic investigation of early metabolic effects of ethylene glycol monomethyl ether (EGME) on male reproductive organs in rats
- Author
-
Takemi Yoshida, Toshinori Yamamoto, and Ikuo Horii
- Subjects
Male ,medicine.medical_specialty ,Magnetic Resonance Spectroscopy ,Time Factors ,Citric Acid Cycle ,Ketone Bodies ,Creatine ,medicine.disease_cause ,Toxicology ,Biomarkers, Pharmacological ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Internal medicine ,Testis ,medicine ,Animals ,Lactic Acid ,Epididymis ,Principal Component Analysis ,Body Weight ,Glutathione ,Organ Size ,Rats ,Citric acid cycle ,Oxidative Stress ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Biochemistry ,Toxicity ,Solvents ,Ethylene Glycols ,Energy Metabolism ,Ex vivo ,Oxidative stress ,Toxicant - Abstract
High-resolution Magic Angle Spinning (Hr-MAS) (1)H-NMR spectroscopy was used to analyze intact testicular tissues ex vivo and to investigate the toxicological effects of ethylene glycol monomethyl ether (EGME), a well-known spermatocytes toxicant, on male reproductive organs by NMR-based metabonomic analysis. Especially, we reported the first Hr-MAS (1)H-NMR spectra of epididymis. Sexually matured male rats were treated with 50 and 2,000 mg/kg EGME, and body weight, reproductive organs weight, histopathology and plasma biochemistry were examined at 6 and 24 hr after administration. Two multivariate statistical methods, namely, unsupervised PCA and supervised PLS-DA, indicated that the balance of endogenous metabolites was perturbed in both reproductive organs and biofluids. In the testes, lactate, creatine and glutathione were mainly affected by EGME treatment. In urine and plasma, altered excretions of the TCA cycle intermediates (2-oxoglutarate, citrate and succinate) and the ketone-bodies (acetoacetate and beta-hydroxybutyrate) were also observed. The finding in current integrated metabonomic analysis of both intact tissues and biofluids suggested that EGME-induced testicular toxicity was attributed to perturbation of the energy supply processes, suppression of the TCA cycle, or oxidative stress. Furthermore, Hr-MAS (1)H-NMR proved useful to investigate the molecular snapshot of biological tissues and the mechanism of toxicity.
- Published
- 2008
46. In vitro gene expression analysis of nephrotoxic drugs in rat primary renal cortical tubular cells
- Author
-
Tomoaki Inoue, Hiromi Suzuki, Kazuko Kobayashi, Ikuo Horii, Tomochika Matsushita, Tohru Inoue, and Yoko Hirabayashi
- Subjects
Male ,medicine.medical_specialty ,Time Factors ,Transcription, Genetic ,Cell Culture Techniques ,Pharmacology ,Biology ,Toxicology ,Nephrotoxicity ,Carboplatin ,Rats, Sprague-Dawley ,In vivo ,Internal medicine ,Toxicity Tests ,medicine ,Cephaloridine ,Animals ,Cluster Analysis ,RNA, Messenger ,Cytotoxicity ,Cells, Cultured ,Oligonucleotide Array Sequence Analysis ,Cisplatin ,Kidney ,Dose-Response Relationship, Drug ,Gene Expression Profiling ,In vitro ,Rats ,medicine.anatomical_structure ,Endocrinology ,Kidney Tubules ,Toxicity ,Feasibility Studies ,Gentamicins ,medicine.drug - Abstract
Rat primary renal cortical tubular cells were exposed to seven test substances, some with, and some without, known direct renal tubular cell toxicity. Cells were exposed to the substances at either one-third or one-tenth of the TC50 for cytotoxicity for 6 h or 24 h, so as not to induce cytotoxicity but to cause some transcriptional changes. Transcriptional profiles were investigated by using the Affymetrix Rat Toxicology U34 arrays, containing probes for more than 850 genes and ESTs. Four direct toxicants, cisplatin (CDDP), its less nephrotoxic analogue carboplatin (CBDCA), cephaloridine and gentamicin, were grouped together in a hierarchical clustering. In addition, the four direct toxicants affected more than 32 transcripts at their subcytotoxic concentrations at either 6 h or 24 h exposure. On the other hand, diclofenac, cyclosporine A and zinc, which are not considered to be directly toxic to tubules, affected less than 12 transcripts. Decreased Map3k12 and increased Hmox1 were commonly observed among the four direct toxicants, which appeared to be responses to cellular damage. Two platinum complexes, CDDP and CBDCA, induced similar changes, regardless of exposure duration or concentration. The types of transcriptional changes observed in this study were consistent with previously reported in vivo data, although there were some differences. These observations suggest that an in vitro gene expression analysis approach using GeneChip is feasible for screening for direct tubular toxicity of drugs and may help to clarify the underlying mechanisms of tubular toxicity. Copyright © 2008 John Wiley & Sons, Ltd.
- Published
- 2008
47. Lipid metabolism in nonspecific productive inflammatory tissue
- Author
-
Ikuo Horii
- Published
- 1990
48. Effect of dose regimen on the toxicity of 2'-deoxy-2'-methylidenecytidine (DMDC) in monkeys
- Author
-
Kazuko Kobayashi, Ikuo Horii, Hidetoshi Shindoh, Akira Kawashima, Nobuyuki Shishido, and Kounosuke Nakano
- Subjects
Male ,2'-deoxy-2'-methylidenecytidine ,Drug Evaluation, Preclinical ,Administration, Oral ,Antineoplastic Agents ,Pharmacology ,Toxicology ,Deoxycytidine ,Drug Administration Schedule ,Recovery period ,chemistry.chemical_compound ,Toxicity Tests ,Medicine ,Toxicokinetics ,Animals ,Humans ,Dosing ,No-Observed-Adverse-Effect Level ,business.industry ,Decreased rbc ,Regimen ,Macaca fascicularis ,chemistry ,Toxicity ,Female ,business - Abstract
2'-Deoxy-2'-methylidenecytidine (DMDC) is a potential anticancer deoxycytidine analog of cytosine arabinoside. Using monkeys, we conducted a 4-week toxicity study with toxicokinetics of DMDC at 1, 3, and 10 mg/kg/day and a dose-regimen study of three different schedules of once-daily administration (5 mg/kg/day) for 1 week every 2 weeks, 2 weeks every 4 weeks, and 3 weeks every 4 weeks. Deaths, myelosuppression, intestinal toxicity, and swelling of palm and sole skin were observed by oral DMDC treatment at 10 mg/kg/day in 4-week repeated toxicity study; however, no skin disorders have been reported in humans. No notable changes were observed at 1 and 3 mg/kg/day. The curves of dose vs. AUC and the AUC at MTD in monkey are similar to those in humans. In the dose-regimen study, all the toxicities were reversible but more severe toxicity was observed with the longer administration periods. One-week interruption showed sufficient recovery of decreased WBC in dosing regimens of 1-week-on/1-week-off and 2-weeks-on/2-weeks-off. A 2-week recovery period was almost sufficient for the recovery of decreased RBC, HCT, and skin disorders in the 2-weeks-on/2-weeks-off regimen. Therefore, once-daily for 2 weeks every 4 weeks was concluded to be the optimal dose regimen. In summary, myelosuppression, intestinal toxicity, and skin disorders were observed in DMDC treatment in monkeys, the relationship between AUC and toxicity in monkeys was close to that in humans, and in preclinical studies, it is advantageous to investigate optimal dose regimens using the appropriate species.
- Published
- 2007
49. Simultaneous measurement of nucleated cell counts and cellular differentials in rat bone marrow examination using flow cytometer
- Author
-
Yoshimasa Hamada, Masaaki Kurata, Takeshi Iidaka, and Ikuo Horii
- Subjects
Male ,Pathology ,medicine.medical_specialty ,Myeloid ,CD3 Complex ,CD3 ,T-Lymphocytes ,Population ,Anthraquinones ,Bone Marrow Cells ,Cell Count ,Biology ,Toxicology ,Stain ,Flow cytometry ,Rats, Sprague-Dawley ,Erythroid Cells ,Nucleated cell ,Antigens, CD ,Receptors, Transferrin ,medicine ,Animals ,Cell Lineage ,Myeloid Cells ,education ,Fluorescent Dyes ,education.field_of_study ,B-Lymphocytes ,CD11b Antigen ,medicine.diagnostic_test ,Reproducibility of Results ,Bone Marrow Examination ,Flow Cytometry ,CD11c Antigen ,Rats ,Bone marrow examination ,medicine.anatomical_structure ,biology.protein ,Leukocyte Common Antigens ,Bone marrow - Abstract
The purpose of this study was to establish the simultaneous measurement of nucleated cell counts and cellular differentials in rat bone marrow examination. The bone marrow cells were stained with an anthraquinone fluorescent DNA stain (DRAQ5) and fluorescence-labeled antibodies, and were analyzed quantitatively using a flow cytometer in the presence of internal standard beads. DRAQ5 distinguished populations of nucleated cells. The absolute counts of nucleated cells were determined using an internal standard, and were equivalent to that measured by the electrical resistance method. The population of nucleated cells was classified into myeloids and erythroids by labeling with CD11b/c and CD71 antibodies, respectively. In a separate examination, T- and B-lymphocytes were also classified by labeling with CD3 and CD45RA antibodies, respectively. The classification of each cell lineage was identical with that of the alternative flow-cytometric method in which cells were differentiated according to cellular size and the fluorescence of a peroxidase indicator, 2',7'-dichlorofluorescin. The ratios of cell lineage, together with myeloid/erythroid ratio (ME), were the same as those obtained by a manual microscopic method. The present flow cytometric method enables the simultaneous measurement of the total nucleated cell counts and cellular differentials of rat bone marrow cells, allowing for rapid and highly quantitative bone marrow examination in rats.
- Published
- 2007
50. [Principles of general toxicology for practical safety assessment]
- Author
-
Ikuo, Horii and Yoshimasa, Hamada
- Subjects
Toxicity Tests ,Animals ,Safety - Published
- 2007
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