- Email: [email protected]
Chronic vascular access by a Vascular-Access-Port in the cynomolgus
PosterSession 3G. Methods
191
Toxicity, Immuno- and Reproductive Toxicity, Carcinogenicity and Genotoxicity, Metabolism and Chemob iokinetics, Carcinogenicity classificatons, Regulatory Data and References . Being regularly updated computer-operating system, the DB covers nearly 2000 indirect food additives and potential food and water contaminants, and will be helpful when evaluating toxic properties not only of existing materials but also of future materials that contain previously investigated ingredients.
Each group of anesthetized rats has been compared to a group of non anesthetized ones. The most significant variations due to anesthesia were observed on five biochemical parameters : glucose, potassium , calcium, phosphorus and alkaline phosphatase levels. The mean values of these parameters remained however within the range commonly generated in our laboratories. This evaluation indicated that the use of this anesthetic technique was appropriate for blood sampling via the retro-orbital sinus in the
IP3G1631
ra l.
DIMETHYL SULFOXIDE PROTECTS ORGANS FROM LOSSOF VIABILITY INDUCED BY WARM ISCHEMIA
J.B. Ulreich *1, M.R. Patel, M. Maveddat, J.L. Boles, P.Z. Nakazato,
Departmentof Surgery/Iransplantation; / Centerfor Toxicology, The University ofArizona, Tucson, AZ, USA At present, many potential transplant patients die waiting for organs. The current donor shortage might be reduced by using organs from non-heart-beating donors (NHBD) . Warm ischemia in NHBD produces damage which can lead to graft failure in recipients posttransplantation. Dimethyl sulfoxide (DMSO) has several well known biological activities which might prevent or reduce such damage . It penetrates cells, is a cellular differentiation agent, scavenges hydroxyl radicals and is a topical anti-inflammatory agent. Male F344 rats were pre-treated with DMSO (2--6 mlIkg, IP) or saline (controls) and were made non-heart-beating for various periods. Alternatively, one lobe of the liver or one kidney was clamped and, after an interval, reperfused . Organs were removed, cold preserved in some cases, cored, precision-cut and incubated in vitro for 4-96 h. Viability of the tissue was determined by measuring potassium (K+) and lactate dehydrogenase (LDH) content. Induction of heat shock proteins (HSP) was also analyzed as they have been shown to increase in cells undergoing stress , heat or chemical damage. The K+ and LDH content indicated that slice viability was significantly decreased in organs SUbjected to 15 minutes or more warm ischemia. Pretreatment with DMSO maintained tissue viability equal to control, non-ischemic organs. HSP were significantly higher in the ischemic tissue compared to controls but were not induced in the DMSO treated group. This suggests that DMSO pretreatment prevents tissue damage in NHBD liver and kidney, thus providing additional organs suitable for transplantation . [Supported by the Arizona Disease Control Research Commission (18U , PZN), the UA Undergraduate Biology Research Program (MRP, JLB , MM), the Richard Siegel Foundation, the American Heart Association , Arizona Affiliate and NIEHS Center Grant P30-ES-06694 (18U)] .
IP3G164 1
CLINICAL BIOCHEMISTRY, HEMATOLOGY, AND HORMONE SAMPLES IN THE RATUNDER ISOFLURANE ANESTHESIA
C. Pfersdorff *, L. Beck, M. Monier, A. Rouaud, E. Penacchio, D. Cahard, F. Lacheretz. Sanofi Recherche, Departmentof
Toxicology and General Pharmacology, 34J84 Monrpellier, France For clinical pathology examinations, the following anesthetic gaseous mixture - 02 61itreslmin + N20 O.6litreslmin + Isoflurane 2% - has been selected to withdraw blood samples via the retro-orbital sinus. The influence of this anesthetic was assessed on blood biochemical parameters usually evaluated in our laboratory. This study was conducted in accordance with Good Laboratory Practices. Animals were divided into four groups of ten males and ten females . Samples were collected at five different timepoints : on Days 1,29,64 and 92; Day 95 was devoted to hormone determination. For Groups 0 and 1, biochemical and hematological samples were collected on different days; for Groups 2 and 3, both samples came from the same puncture .
IP3G16S1
A MODELFOR EFFICACY ANDSAFETY DETERMINATIONS UTIUZINGCONTINUOUS INTRAVENOUS INFUSION IN NUDEMICE
V. B. Ciofalo· 1, T. Cappellonil , T. Loni , C. B. Spainhour" .
/ Chrysalis PreclinicalServices-North America, J()() Discovery Drive, Olyphant, PA J8447, USA; 2Lomir Biomedical, Jnc. , 56 Huot, Notre-Dame, lle Perrot, Quebec, f7V 5V6, Canada Over the past few years there has been a significant increase in the number of potential pharmacologic agents requiring administration via the intravenous route. Coincident with this change has been an increase in the use of continuous infusion. Although effective animal models for continuous infusion have been developed for well over a decade, the mouse has not been routinely used . The mouse is an excellent economic alternative to larger species , since in the early phases of preclinical development sufficient material may not be available for the performance of studies with dose levels necessary to assess the relative safety of a compound. Animals were anesthetized with a ketamine-xylazine mixture and a silastic medical grade catheter implanted under aseptic conditions. The catheter was connected to a clinical grade infusion pump via tether and swivel. Animals were infused with isotonic saline at rates ranging from 1.5-8.0 ml/kglhr for periods of up to 21 days. After transient postsurgical reductions in body weights, body weight gains and food consumption values, animals demonstrated no adverse clinical signs due to the presence of the catheter. Gross pathology findings were restricted to those referahle to the healing surgical site. Histomorphological evaluation revealed no significant alterations from normal other than a mild degree of fibrosis at the site of introduction of the catheter. When compared to age-and sex-matched untreated controls, no statistically significant differences in hematological or clinical chemical parameters were observed . The procedures developed here have been extended to include nude mice and the development of tumor burden models to assess the efficacy of oncologic therapeutic agents in an efficient manner. Data in support of this extension is also presented.
IP3G1661 CHRONIC VASCULAR ACCESS BY A
VASCULAR·ACCES5-PORT IN THE CYNOMOLGUS
M. Rivals *, M. Gobron, T. Truphemus . Synthelabo Recherche,
Gargenville, France The phylogenetic and physiological similarity between man and the non-human primate has resulted in an increased demand for cynomolgus monkeys in safety and efficacy assessment of new drugs. Intraveinous techniques have become considerably more important, especially with the development of biotechnology products . The Vascular-Access-Port can provide chronic vascular access for intermittent delivery of fluids, particularly irritants fluids or blood sampling and eliminates multiples venipunctures . The results show that surgery does not modify the haematological and coagulation parameters (white blood cells, red blood cells, platelets, Quick time and actived cephaline time). The administration of fluid via the port system does not reveal any technicals problems ; nevertheless, blood
192
Poster Session 3G. Methods
sampling is not very easy, it is not possible to systematically take blood probably due to the system's small size. The Vascular-AccessPort as a totally implantable drug delivery system proved to be safe, humane and easy device to handle, which provided chronic vascular access without multiple venipunctures.
I
P3G 167 1 BONE MINERALDENSITYASSESSMENT BY DXA TO ASSESS EFFICACYAND SAFETYOF NEW DRUGS IN RATSAND MONKEYS
C. Fisch *, R. Forster. CIT Centre International de Toxicologie, BP 563, Miserey, 27005 Evreux; France Animal models are essential for the discovery and development of therapeutic approaches which act on bone growth and resorption . In our laboratories we have established and validated techniques for the determination and monitoring of bone mineral density (BMD) in rats and monkeys in vivo and ex vivo. In this way both bone modeling (rat) and remodeling (monkey) species can be studied, as required by current international regulatory guidelines. We have validated the use of DXA (Dual Energy X-Ray Absorptiometry) for BMD measurements. This non-invasive technique permits in vivo monitoring of rat bone density as well as ex vivo measurements on rat bones after sacrifice. The variability of repeated measurements on the same animal and within-animal variation have been estimated. We have developed reference data on populations of normal young and aged (6 month old) rats, and of ovariectomised aged rats. Bone density has been followed for periods of up to six months for sham operated rats, ovariectomised control rats and rats treated with reference compounds. The data show the decline of bone density in ovariectomised rats, and the beneficial effect of treatment with the reference compounds (bisphosphonates and oestrogens). Methods have been similarly been validated for DXA deterrninations in vivo and ex vivo on cynomolgus monkeys (Macaca fas cicularis). Reference data are available for lumbar vertebrae and femora of normal and ovariectomised monkeys. Complemented by data from blood and urinary biochemical markers, biomechanical measurements and histomorphom etric parameters, these techniques allow a comprehensive evaluation of bone dynam ics in these two species.
1P3G 1681 AN EXPERIMENTAL MODEL FOR OSTEOARTHROSIS
I. Fulop *1 , R. Glavits'', M. Kovacs 1 , Gy. Sebestyen 1 . }Pharmaceutical Control and Developing Laboratory Co. Ltd.; 2Central Veterinary Institute Budapest, Hungary An experimental model for chronic joint inflammation was developed in New-Zealand white rabbits, based on the method of Bentley. The study was initiated to obtain a model that can be used for the testing of intra-articular formulati ons. Arthrosis in the animals was induced by giving three intra-articular injections of sterile papain solution (2% or 3%) into the elbow joint of rabbits. The effect of injection s in vivo was monitored by weekly measurement of elbow diameters in medio-lateral and sagittal directions. Macroscopic and microscopic evaluation of joint cartilages were carried out 3 times during the induction period of 12 weeks. Results: Elbow joint diameter: severe jo int swelling was observed immediately after each papain injection which disappeared on the next day. After the third papain injection. however, the swelling became permanent and persisted during the observation period of 12 weeks. Macroscopic evaluation of cartilage: no macroscopic alterations were found in the animals given one or two papain treatment, Well defined lesions were seen, on the 12th week of the study, on the cartilage of animals given three papain injections. The lesions were:
opaque, yellowish, rough cartilage surface, erosio ns in the hole of epicondyles. Microscopic evaluation: extensive chondrocyte death in the superficial and deeper layers of cartilage, rough surface and different erosions were observed in hematoxylin-eosin (H-E) stained slides and progredient glycosarninoglycan loss of joint cartilage was seen in Periodic Acid Schiff (PAS) stained slides. The symptoms induced by papin treatment were characteristic for the chronic arthrosis disease and the model can be useful for testing intra-articular formulations .
IP3G 1691
TOXICANTIDENTIFICATION AND CLASSIACATION USINGeDNA MICROARRAY TECHNOLOGY
E.P. Nuwaysir *1 , M. Bittne? , L. Annab 1 , P.L. Cable 1 , J. Trenr' , lC. Barrett" , C. Afshari", }National Institute ofEnvironmental Health Sciences; 2 National Human Genome Research Institute, National Institutes ofHealth, USA One of the main challenges facing investigators in environmental health research is hazard identification. cDNA microarray technology, which allows for the simultaneou s monitoring of expression levels for thousands of genes , has the potential to revolutionize the way this identification is accomplished. Given that exposure to different classes of toxicants results in distinct patterns of altered gene expression, microarray technology can be utilized to classify these effects. In defined model systems, treatment with known agents such as polycyclic aromatic hydrocarbons. dioxins, peroxisome proIiferators, estrogenic compounds , or oxidant stressors, can provide a gene expression "signature" on a microarray which represents the cellular response to these agents. These same systems can then be treated with unknown, suspect agents to deterrnine if one or more of these standard signatures is elicited. The data derived from this approach is inherently mechanistic, and can be used to suggest a general mechani sm of action for suspected toxicants. In addition, these studies lend insight into the necessity for testing the agent in the more expensive, time-consuming traditional bioassays. We have designed and manufactured a "Toxicant Response Chip" (ToxChip) which contain s approximately 2000 genes involved in cellular responses to toxic insult. including cell cycle genes, oxidative stress genes, xenobiotic metabolizing enzymes, and apoptotic cell death genes. Using ToxChip, our initial efforts have focused on the characterization of a prototypical "estrogenic" response in the estrogen-responsive human ovarian carcinoma-derived cell line BG 1, as well as studies on oxidative stress in the human colon carcinoma-derived cell line RKO.
IP3G 170 I ARE IN VITROTESTS PREDICTIVE OF QT PROLONGATION IN HUMANAS IN VIVOTOXICITY STUDIESARE?THE EXAMPLEOF WIN33377
P. Gautier *, A. Roberts, J.P. Bertrand , A. Barbier, J. Popp, D. Nisato, F. Lacheretz. Sanofi Recherche, Montpellier; France; Sanofi Inc Great Valley, USA Effects of WIN3 3377 (Sanofi Recherche) on cardiac function were evaluated in vitro using Purkinje and ventricular fibers tests and in vivo by EEG measurements during toxicity study in the dog. The same electrocardiographic evaluation was performed in humans during phase I. Cellular electrophysiology studies were carried out on the excitation-contraction coupling in papillary muscle and on action potential (AP) of Purkinje fibers of rabbit heart. Experiments were performed in normal Tyrode's solution ([K+lo =4 mM) at stimulation frequency of 60 b/min with a rapid change to a low frequency (12 b/min ). The dog experiment was a 5-day administration study, with a 2 h-i.v. infusion/day at 2.5 and 5 mg/kg (50-100 mg/m 2 ) . Human single i.v. administrations were performed up to the dose of 445 mg/m".
191
Toxicity, Immuno- and Reproductive Toxicity, Carcinogenicity and Genotoxicity, Metabolism and Chemob iokinetics, Carcinogenicity classificatons, Regulatory Data and References . Being regularly updated computer-operating system, the DB covers nearly 2000 indirect food additives and potential food and water contaminants, and will be helpful when evaluating toxic properties not only of existing materials but also of future materials that contain previously investigated ingredients.
Each group of anesthetized rats has been compared to a group of non anesthetized ones. The most significant variations due to anesthesia were observed on five biochemical parameters : glucose, potassium , calcium, phosphorus and alkaline phosphatase levels. The mean values of these parameters remained however within the range commonly generated in our laboratories. This evaluation indicated that the use of this anesthetic technique was appropriate for blood sampling via the retro-orbital sinus in the
IP3G1631
ra l.
DIMETHYL SULFOXIDE PROTECTS ORGANS FROM LOSSOF VIABILITY INDUCED BY WARM ISCHEMIA
J.B. Ulreich *1, M.R. Patel, M. Maveddat, J.L. Boles, P.Z. Nakazato,
Departmentof Surgery/Iransplantation; / Centerfor Toxicology, The University ofArizona, Tucson, AZ, USA At present, many potential transplant patients die waiting for organs. The current donor shortage might be reduced by using organs from non-heart-beating donors (NHBD) . Warm ischemia in NHBD produces damage which can lead to graft failure in recipients posttransplantation. Dimethyl sulfoxide (DMSO) has several well known biological activities which might prevent or reduce such damage . It penetrates cells, is a cellular differentiation agent, scavenges hydroxyl radicals and is a topical anti-inflammatory agent. Male F344 rats were pre-treated with DMSO (2--6 mlIkg, IP) or saline (controls) and were made non-heart-beating for various periods. Alternatively, one lobe of the liver or one kidney was clamped and, after an interval, reperfused . Organs were removed, cold preserved in some cases, cored, precision-cut and incubated in vitro for 4-96 h. Viability of the tissue was determined by measuring potassium (K+) and lactate dehydrogenase (LDH) content. Induction of heat shock proteins (HSP) was also analyzed as they have been shown to increase in cells undergoing stress , heat or chemical damage. The K+ and LDH content indicated that slice viability was significantly decreased in organs SUbjected to 15 minutes or more warm ischemia. Pretreatment with DMSO maintained tissue viability equal to control, non-ischemic organs. HSP were significantly higher in the ischemic tissue compared to controls but were not induced in the DMSO treated group. This suggests that DMSO pretreatment prevents tissue damage in NHBD liver and kidney, thus providing additional organs suitable for transplantation . [Supported by the Arizona Disease Control Research Commission (18U , PZN), the UA Undergraduate Biology Research Program (MRP, JLB , MM), the Richard Siegel Foundation, the American Heart Association , Arizona Affiliate and NIEHS Center Grant P30-ES-06694 (18U)] .
IP3G164 1
CLINICAL BIOCHEMISTRY, HEMATOLOGY, AND HORMONE SAMPLES IN THE RATUNDER ISOFLURANE ANESTHESIA
C. Pfersdorff *, L. Beck, M. Monier, A. Rouaud, E. Penacchio, D. Cahard, F. Lacheretz. Sanofi Recherche, Departmentof
Toxicology and General Pharmacology, 34J84 Monrpellier, France For clinical pathology examinations, the following anesthetic gaseous mixture - 02 61itreslmin + N20 O.6litreslmin + Isoflurane 2% - has been selected to withdraw blood samples via the retro-orbital sinus. The influence of this anesthetic was assessed on blood biochemical parameters usually evaluated in our laboratory. This study was conducted in accordance with Good Laboratory Practices. Animals were divided into four groups of ten males and ten females . Samples were collected at five different timepoints : on Days 1,29,64 and 92; Day 95 was devoted to hormone determination. For Groups 0 and 1, biochemical and hematological samples were collected on different days; for Groups 2 and 3, both samples came from the same puncture .
IP3G16S1
A MODELFOR EFFICACY ANDSAFETY DETERMINATIONS UTIUZINGCONTINUOUS INTRAVENOUS INFUSION IN NUDEMICE
V. B. Ciofalo· 1, T. Cappellonil , T. Loni , C. B. Spainhour" .
/ Chrysalis PreclinicalServices-North America, J()() Discovery Drive, Olyphant, PA J8447, USA; 2Lomir Biomedical, Jnc. , 56 Huot, Notre-Dame, lle Perrot, Quebec, f7V 5V6, Canada Over the past few years there has been a significant increase in the number of potential pharmacologic agents requiring administration via the intravenous route. Coincident with this change has been an increase in the use of continuous infusion. Although effective animal models for continuous infusion have been developed for well over a decade, the mouse has not been routinely used . The mouse is an excellent economic alternative to larger species , since in the early phases of preclinical development sufficient material may not be available for the performance of studies with dose levels necessary to assess the relative safety of a compound. Animals were anesthetized with a ketamine-xylazine mixture and a silastic medical grade catheter implanted under aseptic conditions. The catheter was connected to a clinical grade infusion pump via tether and swivel. Animals were infused with isotonic saline at rates ranging from 1.5-8.0 ml/kglhr for periods of up to 21 days. After transient postsurgical reductions in body weights, body weight gains and food consumption values, animals demonstrated no adverse clinical signs due to the presence of the catheter. Gross pathology findings were restricted to those referahle to the healing surgical site. Histomorphological evaluation revealed no significant alterations from normal other than a mild degree of fibrosis at the site of introduction of the catheter. When compared to age-and sex-matched untreated controls, no statistically significant differences in hematological or clinical chemical parameters were observed . The procedures developed here have been extended to include nude mice and the development of tumor burden models to assess the efficacy of oncologic therapeutic agents in an efficient manner. Data in support of this extension is also presented.
IP3G1661 CHRONIC VASCULAR ACCESS BY A
VASCULAR·ACCES5-PORT IN THE CYNOMOLGUS
M. Rivals *, M. Gobron, T. Truphemus . Synthelabo Recherche,
Gargenville, France The phylogenetic and physiological similarity between man and the non-human primate has resulted in an increased demand for cynomolgus monkeys in safety and efficacy assessment of new drugs. Intraveinous techniques have become considerably more important, especially with the development of biotechnology products . The Vascular-Access-Port can provide chronic vascular access for intermittent delivery of fluids, particularly irritants fluids or blood sampling and eliminates multiples venipunctures . The results show that surgery does not modify the haematological and coagulation parameters (white blood cells, red blood cells, platelets, Quick time and actived cephaline time). The administration of fluid via the port system does not reveal any technicals problems ; nevertheless, blood
192
Poster Session 3G. Methods
sampling is not very easy, it is not possible to systematically take blood probably due to the system's small size. The Vascular-AccessPort as a totally implantable drug delivery system proved to be safe, humane and easy device to handle, which provided chronic vascular access without multiple venipunctures.
I
P3G 167 1 BONE MINERALDENSITYASSESSMENT BY DXA TO ASSESS EFFICACYAND SAFETYOF NEW DRUGS IN RATSAND MONKEYS
C. Fisch *, R. Forster. CIT Centre International de Toxicologie, BP 563, Miserey, 27005 Evreux; France Animal models are essential for the discovery and development of therapeutic approaches which act on bone growth and resorption . In our laboratories we have established and validated techniques for the determination and monitoring of bone mineral density (BMD) in rats and monkeys in vivo and ex vivo. In this way both bone modeling (rat) and remodeling (monkey) species can be studied, as required by current international regulatory guidelines. We have validated the use of DXA (Dual Energy X-Ray Absorptiometry) for BMD measurements. This non-invasive technique permits in vivo monitoring of rat bone density as well as ex vivo measurements on rat bones after sacrifice. The variability of repeated measurements on the same animal and within-animal variation have been estimated. We have developed reference data on populations of normal young and aged (6 month old) rats, and of ovariectomised aged rats. Bone density has been followed for periods of up to six months for sham operated rats, ovariectomised control rats and rats treated with reference compounds. The data show the decline of bone density in ovariectomised rats, and the beneficial effect of treatment with the reference compounds (bisphosphonates and oestrogens). Methods have been similarly been validated for DXA deterrninations in vivo and ex vivo on cynomolgus monkeys (Macaca fas cicularis). Reference data are available for lumbar vertebrae and femora of normal and ovariectomised monkeys. Complemented by data from blood and urinary biochemical markers, biomechanical measurements and histomorphom etric parameters, these techniques allow a comprehensive evaluation of bone dynam ics in these two species.
1P3G 1681 AN EXPERIMENTAL MODEL FOR OSTEOARTHROSIS
I. Fulop *1 , R. Glavits'', M. Kovacs 1 , Gy. Sebestyen 1 . }Pharmaceutical Control and Developing Laboratory Co. Ltd.; 2Central Veterinary Institute Budapest, Hungary An experimental model for chronic joint inflammation was developed in New-Zealand white rabbits, based on the method of Bentley. The study was initiated to obtain a model that can be used for the testing of intra-articular formulati ons. Arthrosis in the animals was induced by giving three intra-articular injections of sterile papain solution (2% or 3%) into the elbow joint of rabbits. The effect of injection s in vivo was monitored by weekly measurement of elbow diameters in medio-lateral and sagittal directions. Macroscopic and microscopic evaluation of joint cartilages were carried out 3 times during the induction period of 12 weeks. Results: Elbow joint diameter: severe jo int swelling was observed immediately after each papain injection which disappeared on the next day. After the third papain injection. however, the swelling became permanent and persisted during the observation period of 12 weeks. Macroscopic evaluation of cartilage: no macroscopic alterations were found in the animals given one or two papain treatment, Well defined lesions were seen, on the 12th week of the study, on the cartilage of animals given three papain injections. The lesions were:
opaque, yellowish, rough cartilage surface, erosio ns in the hole of epicondyles. Microscopic evaluation: extensive chondrocyte death in the superficial and deeper layers of cartilage, rough surface and different erosions were observed in hematoxylin-eosin (H-E) stained slides and progredient glycosarninoglycan loss of joint cartilage was seen in Periodic Acid Schiff (PAS) stained slides. The symptoms induced by papin treatment were characteristic for the chronic arthrosis disease and the model can be useful for testing intra-articular formulations .
IP3G 1691
TOXICANTIDENTIFICATION AND CLASSIACATION USINGeDNA MICROARRAY TECHNOLOGY
E.P. Nuwaysir *1 , M. Bittne? , L. Annab 1 , P.L. Cable 1 , J. Trenr' , lC. Barrett" , C. Afshari", }National Institute ofEnvironmental Health Sciences; 2 National Human Genome Research Institute, National Institutes ofHealth, USA One of the main challenges facing investigators in environmental health research is hazard identification. cDNA microarray technology, which allows for the simultaneou s monitoring of expression levels for thousands of genes , has the potential to revolutionize the way this identification is accomplished. Given that exposure to different classes of toxicants results in distinct patterns of altered gene expression, microarray technology can be utilized to classify these effects. In defined model systems, treatment with known agents such as polycyclic aromatic hydrocarbons. dioxins, peroxisome proIiferators, estrogenic compounds , or oxidant stressors, can provide a gene expression "signature" on a microarray which represents the cellular response to these agents. These same systems can then be treated with unknown, suspect agents to deterrnine if one or more of these standard signatures is elicited. The data derived from this approach is inherently mechanistic, and can be used to suggest a general mechani sm of action for suspected toxicants. In addition, these studies lend insight into the necessity for testing the agent in the more expensive, time-consuming traditional bioassays. We have designed and manufactured a "Toxicant Response Chip" (ToxChip) which contain s approximately 2000 genes involved in cellular responses to toxic insult. including cell cycle genes, oxidative stress genes, xenobiotic metabolizing enzymes, and apoptotic cell death genes. Using ToxChip, our initial efforts have focused on the characterization of a prototypical "estrogenic" response in the estrogen-responsive human ovarian carcinoma-derived cell line BG 1, as well as studies on oxidative stress in the human colon carcinoma-derived cell line RKO.
IP3G 170 I ARE IN VITROTESTS PREDICTIVE OF QT PROLONGATION IN HUMANAS IN VIVOTOXICITY STUDIESARE?THE EXAMPLEOF WIN33377
P. Gautier *, A. Roberts, J.P. Bertrand , A. Barbier, J. Popp, D. Nisato, F. Lacheretz. Sanofi Recherche, Montpellier; France; Sanofi Inc Great Valley, USA Effects of WIN3 3377 (Sanofi Recherche) on cardiac function were evaluated in vitro using Purkinje and ventricular fibers tests and in vivo by EEG measurements during toxicity study in the dog. The same electrocardiographic evaluation was performed in humans during phase I. Cellular electrophysiology studies were carried out on the excitation-contraction coupling in papillary muscle and on action potential (AP) of Purkinje fibers of rabbit heart. Experiments were performed in normal Tyrode's solution ([K+lo =4 mM) at stimulation frequency of 60 b/min with a rapid change to a low frequency (12 b/min ). The dog experiment was a 5-day administration study, with a 2 h-i.v. infusion/day at 2.5 and 5 mg/kg (50-100 mg/m 2 ) . Human single i.v. administrations were performed up to the dose of 445 mg/m".