• Archives of Pharmacal Research
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• v.27 no.5
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• pp.547-553
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• 2004

The pyrrolizidine alkaloids (PAs), contained in a number of traditional remedies in Africa and Asia, show wide variations in metabolism between animal species but little work has been done to investigate differences between animal strains. The metabolism of the PA senecionine (SN) in Fischer 344 (F344) rats has been studied in order to compare to that found in the previously investigated Sprague-Dawley (SO) rats (Drug Metab. Dispos. 17: 387, 1989). There was no difference in the formation of ($\pm$) 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP, bioactivation) by hepatic microsomes from either sex of SO and F344 rats. However, hepatic microsomes from male and female F344 rats had greater activity in the Noxidation (detoxication) of SN by 88% and 180%, respectively, when compared to that of male and female SD rats. Experiments conducted at various pH showed an optimum pH of 8.5, the optimal pH for flavin-containing monooxygenase (FMO), for SN N-oxidation by hepatic microsomes from F344 females. In F344 males, however, a bimodal pattern was obtained with activity peaks at pH 7.6 and 8.5 reflecting the possible involvement of both cytochrome P450 (CYP) and FMO. Use of specific inhibitors (SKF525A, 1-benzylimidazole and methimazole) showed that the N-oxide of SN was primarily produced by FMO in both sexes of F344 rats. In contrast, SN N-oxide formation is known to be catalyzed mainly by CYP2C11 rather than FMO in SD rats. This study, therefore, demonstrated that there were substantial differences in the formation of SN N-oxide by hepatic microsomes from F344 and SD rats and that this detoxification is catalyzed primarily by two different enzymes in the two rat strains. These findings suggest that significant variations in PA biotransformation can exist between different animal strains.

• Biomolecules & Therapeutics
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• v.3 no.1
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• pp.12-20
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• 1995

Clofibrate, a peroxisome proliferator, is hepatocarcinogenic in rats in a dose-dependent manner. A total of 70 male and female F344 rats, 5-week-old, were divided into three groups. Rats were fed clofibrate at 0, 0.25, or 0.5% in diet for 30 days. All rats were anesthetized with $CO_2$, blood samples were taken by cardiac puncture for hematology and clinical chemistry, and the rats were killed by exsanguination. Livers, kidenys, pancreas, adrenal glands, spleen, heart, lungs, thyroid gland, reproductive organs, and digestive organs were removed, weighed, later processed, and embedded with paraplast for histological examination. The relative liver and kidney weights with respect to final body weight in the clofibrate-treated group were significantly increased compared with those of control group at all dose levels (p<0.01). It has been suggested that clofibrate may influence on hepatotoxicity by increases in peroxisomal proliferation.

• Natural Product Sciences
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• v.22 no.3
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• pp.180-186
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• 2016

This research is to estimate the toxicity of Atractylodis Rhizoma Alba (ARA) in F344 rats and to find a dose level for the 13 weeks toxicity study. A hot water extract of ARA (ARWE) was administered orally to F344 rats at dose levels of 0 (vehicle control), 500, 1000, 2000, 3500, and 5000 mg/kg/day for 2 weeks. Each group was composed to five male and five female F344 rats. According to the result, there were no ARWE-related adverse changes in mortality, body weights, food consumption, urinalysis, hematology, clinical chemistry, gross finding at necropsy, and organ weight examination. Salivation was observed in 3500 and 5000 mg/kg/day in male and female rats but it could not have found any relationship with ARWE administration. Based on our findings, ARWE may not cause toxicity in rats under the experimental conditions. Therefore, dose level of 5000 mg/kg/day as a highest treatment group in 13-week exposure study is recommended for further toxicity assessment.

• Korean Journal of Veterinary Pathology
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• v.1 no.1
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• pp.46-52
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• 1997

The hematology and clinical chemistry data based on the well defined normal data are essential in the safety assessment. It is important that normal values of cliniclal pathology parameters would be optimized to be accurate. So the purpose of this experiment was to compare the ranges of normal data in hematology value and serum chemistry between both sexes of F344 and Wistar rats at 5, 10, 20, 40 and 90 weeks. of age. The neutrophils eosinophils and monocytes increased with age in male Wistar rats. And serum total bilirubin and potassium were highest and alkaline phosphatase was lowest at 90 weeks in Wistar rats. As compared with Wistar rat the serum aspartate aminotransferase of F344 rats increased with age in both sexes but inorganic phosphorus decreased with age. The serum alkaline phosphatase decreased with age and potassium was highest at 90weeks. These normal data would be useful in improving the accuracy of clinical pathology value in the safety assessment.

• Biomolecules & Therapeutics
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• v.10 no.3
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• pp.193-199
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• 2002

The arylamine N-acetyltransferases (NATs) are a family of enzymes that N-acetylate mylhydrazines and arylamines through transfer of an acetyl group from acetyl coenzyme A. This activity was found to vary among individuals as a Mendalian trait and the basis of the genetic differences in human NAT activity is one of the best of the genetic studied examples of pharmacogenetic variation. The classical N-acetylation polymorphism is regulated at the NAT2 locus, which segregates individuals into rapid, intermediate, and slow acetylator phenotypes. In this study, the relationship between NAT2 activity phenotype using HPLC:UV assay for the determination of dapsone and monoacetyldapsone in plasma and NAT2 genotype by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) was investigated in the F2 hybrid (Fischer 344 vs Wistar-Kyoto) rats. Three Common mutant alleles at the NAT2 gene locus have been identified in the F2 generation progeny of Fischer 344 rats as raid acetylator and Wistar-Kyoto rats as slow acetylator segregated into three modes (low, intermediates, and high) with simple Mendelian inheritance. The metabolic activity of NAT2 of the intermediate and rapid acetylators is significant1y greater than slow acetylator, but the metabolic activity of rapid acetylator is not significantly different from Intermediate type. Therefore, we could observe that complete trimodal NAT2 genotypic alleles and incomplete trimodal NAT2 metabolic phenotypic distribution in tile F2 hybrid rats. These observations suggest that the relationships between NAT2 genotype and metabolic phenotype exists and F2 hybrid (Fischer 344: Wistar-Kyoto) animal models about NAT2 polymorphism might be applied in the toxicity and pharmacogenetic studies of arylamine drugs and carcinogens.

• Natural Product Sciences
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• v.21 no.1
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• pp.34-41
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• 2015

The objective of this study is to characterize a toxicity of Epimedii Herba (EH) in F344 rats and to find a dose levels for the 13 weeks toxicity study. EH is well known as medicinal herb in many Asian countries for traditional medicines of antibacterial and antiviral effects, estrogenic and antiestrogenic effects, and for treatment of osteoporosis, hypotensives, fatigue, kidney disorders, and related complications. However, the indispensable and basic information of toxicological evaluation of EH extract is insufficient to support its safe use. Therefore, we conducted toxicological evaluation of this drug in compliance with OECD and MFDS guideline in this study. The extract of EH was administered orally to F344 rats at dose levels of 0, 500, 1000, 2000, 3500, and 5000 mg/kg/day for 2 weeks. Each group was composed of 5 male and female rats. In this study, there were no treatment of EH-related adverse changes in clinical observations, mortality, body weights, food consumption, urinalysis, gross finding at necropsy, and organ weight examination. Total red blood cell count, hematocrit, mean corpuscular hemoglobin concentration, total cholesterol, and phospholipid were decreased in males and females at 5000 mg/kg/day compared to the control animals. Mean corpuscular volume and reticulocyte counts were increased in males and females at 5000 mg/kg/day compared to control animals. Therefore, we recommend that dose level of 5000 mg/kg/day is a highest treatment group in 13-week EH extract exposure study for further toxicity assessment.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2002.11a
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• pp.12-20
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• 2002

1. 질병명 : Interstitial pneumonia 2. 본질명의 개요 역사 및 역학 Michael R Elwell, Joel F Mahler, G N Rao: “ Have You Seen This\ulcorner" ; Inflammatory Lesions in the Lungs of Rats. Toxicologic Pathology, 25: 529-531, 1997. Male and female F344 rats, approximately 19 weeks old, from prechronic toxicity studies performed for NTP/NIEHS over a period of several years at different laboraories located throughout the US. The rats were supplied by 2 different production colonies located in the eastern and western areas of the US. Gross findings ㆍ In some rats the lesions were noted as pale or tan foci in the lungs Microscopic findings ㆍ A prominent increase in perivascular lymphocytes ㆍ A variable increase in the amount of peribronchiolar lymphoid tissues ㆍ Frequently an inflammatory cell exudate within the alveolar spaces ㆍ Focal hyperplasia of alveolar type 2 cells Similar lung lesions were not observed in B6C3F1 mice concurrently on study with affected rats. Similar lung lesions were not observed in F344 rats at the end of 2-year NTP studies. Virus, mycoplasma, bacterial serology, bacterial culture, protozoal identification: negative EM: ㆍ No virus particles were identified. ㆍ Rod shaped bacteria were observed in the alveolar spaces. ㆍ Bacteria were not observed in the bronchi/ bronchioles of rats with alveolar organism. (omitted)

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.635-640
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• 1992

Two cases of lingual masses were observed among 500 Fischer 344 (F344) rats which were used as control and treated animals in a 2 year carcinogenicity study in Toxicology Research Center, Korea Research Institute of Chemical Technology. The masses grossly appeared as tan, pedunculated, fungiform on the dorsal aspect of the base of the tongues. They were approximately $1.5{\times}1.2{\times}0.3cm$ in size. The microscopic features consisted of acanthosis, hyperkeratosis, papillary projection with connective tissue cores and multifocal chronic active inflammation with hair shafts. The results observed support the epigenetic mechanism of tumorigenesis which is caused by Physical stimuli of foreign bodies. Both of the masses were diagnosed as papillomas with the incidence rate of 0.4%(1/250) in each sex on the basis of the gross and microscopic features.

• Journal of Chest Surgery
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• v.29 no.7
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• pp.713-722
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• 1996

Poor long term patient survival (60% at 2 years) in lung allograft recipients are mainly due to rejection and complications associated with the use of nonspecific immunosuppressants. Better means to achieve waft acceptance is desperately needed. 1 have investigated whether mixed allogeneic chimerism in the form of bone marrow stem cell engraftment would induce donor-specific tolerance for lung allografts. Fisher (F344) and Wistar Forth (WF)rats were lethally irradiated (1100c0y) and reconstituted with a mixture of T-cell depleted syngeneic and allogeneic bone marrow (F344+WFIWF, ACI +F344- F344). After Mixed chimerism was documented by peripheral blood Ipnphocyte typing at 28 days, orthotopic left single lung transplantation was performed, using donor-s ecific or third party allografts. No immunosuppressants were administered. Graft rejection was monitored by chest rentgenography, and con- firmed by histology Mixed chimeric rats accepted lung allografts permanently, and it was not strain specific effect. Tolerance was all or none phenomenon which had nothing to do with the percentage of chimerlsm. Mixed chimeras rejected third party allografts in less than 10 days, a time course similar to that of unmanipulated controls. No acute or chronic rejection was observed in donor specific grafts more than 150 days posttransplant. These data suggest that mixed chimerism in the form of bone marrow stem cell engraftment results in stable, systemic donor-specific transplantation tolerance for lung allografts.

• Nutrition Research and Practice
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• v.4 no.6
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• pp.470-476
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• 2010

The resistant dextrin NUTRIOSE$^{(R)}$, developed from starch, is expected to act as a prebiotic. The aim of this study was to determine the effects of NUTRIOSE$^{(R)}$ on cecal parameters, short-chain fatty acid (SCFA) concentrations, and fecal excretion in rats. In an initial experiment, twenty-four male Fischer F344 rats were randomly assigned to one of the following four treatments for 14 days: G0 (control diet), G2.5 (control diet+2.5% of dextrin), G5 (control diet + 5% of dextrin), and G10 (control diet + 10% of dextrin). After 14 days, total cecal weight, cecal content, and cecal wall weight were significantly increased in G5 and G10 compared to G0. At the same time, cecal pH was significantly lower in G10 compared to G0. Total SCFA concentration was significantly higher in G10 than in G5, G2.5, and G0, and significantly higher in G5 than in G0. Acetate, butyrate, and propionate concentrations were significantly increased in G5 and G10 compared to the controls. In a second trial based on a similar design, eighteen male Fischer F344 rats were treated with a control diet supplemented with 5% of dextrin or 5% of fructo-oligosaccharide. The results obtained with NUTRIOSE$^{(R)}$ were similar to those obtained with the fructo-oligosaccharide. In a third experiment, two groups of 5 Fischer F344 rats were orally treated with 100 and 1,000 mg/kg NUTRIOSE$^{(R)}$, respectively, and from 18% to 25% of the dextrin was excreted in the feces. The results of these three studies show that the consumption of NUTRIOSE$^{(R)}$, by its effects on total cecal weight, cecal content, cecal wall weight, pH, and SCFA production, could induce healthy benefits since these effects are reported to be prebiotic effects.