A combined repeated-dose toxicity study with reproduction was conducted with 2-pentenenitrile (2-... more A combined repeated-dose toxicity study with reproduction was conducted with 2-pentenenitrile (2-PN). Rats (10/sex per dose level) were dosed with 2-PN once daily by gavage at dose levels of either 0, 1, 3, or 10 mg kg(-1) day(-1) for 28 days, prior to and during cohabitation, and through day 3 of lactation. General clinical observations were recorded daily; body weights were recorded weekly. A neurobehavioral evaluation consisting of a functional observational battery and motor activity was conducted in all parental rats (10/sex per group). Clinical pathology parameters (hematology, clinical chemistry, coagulation) were measured in parental rats. Pup weights and clinical signs were recorded at birth and on lactation day 4. Parental rats were given a gross pathological examination, organ weights were obtained, and histological examination was conducted for the control and 10 mg kg(-1) day(-1) groups. No effects were seen with regard to mortality, clinical signs, functional observational battery and motor activity, hematology, or organ weights. Females receiving 10 mg/kg and males from all dose groups showed lower body weight gains and feed efficiency. Increased albumin concentrations were seen in both sexes given 10 mg/kg. Females in the 10 mg/kg group showed degeneration of the olfactory mucosa. No effects on the numbers of pups born, number surviving to lactation day 4, pup weight, and no gross anatomical development changes were observed. Under the conditions of this study, the no-observed-effect level (NOEL) for systemic toxicity in rats was 3 mg kg(-1) day(-1), based on degeneration of olfactory mucosa in females at 10 mg kg(-1) day(-1). The NOEL for reproductive and neurobehavioral toxicity in rats and for toxicity to offspring was 10 mg kg(-1) day(-1), the highest dose level tested.
The diverse functions of thyroid hormone (T3) are presumed to be mediated by two genes encoding t... more The diverse functions of thyroid hormone (T3) are presumed to be mediated by two genes encoding the related receptors, TRalpha and TRbeta. However, the in vivo functions of TRalpha and TRbeta are undefined. Here, we report that targeted inactivation of the mouse TRbeta gene results in goitre and elevated levels of thyroid hormone. Also, thyroid-stimulating hormone (TSH), which is released by pituitary thyrotropes and which is normally suppressed by increased levels of thyroid hormone, was present at elevated levels in homozygous mutant (Thrb-/-) mice. These findings suggest a unique role for TRbeta that cannot be substituted by TRalpha in the T3-dependent feedback regulation of TSH transcription. Thrb-/- mice provide a recessive model for the human syndrome of resistance to thyroid hormone (RTH) that exhibits a similar endocrine disorder but which is typically caused by dominant TRbeta mutants that are transcriptional inhibitors. It is unknown whether TRalpha, TRbeta or other recept...
The effects of inhaled methyl iodide (MeI) on clinical pathology parameters, glutathione (GSH) ti... more The effects of inhaled methyl iodide (MeI) on clinical pathology parameters, glutathione (GSH) tissue levels, serum thyroid hormone and inorganic iodide concentrations, S-methylcysteine hemoglobin concentrations, and liver UDP-glucuronyltransferase activity were studied in the rat. Male rats were exposed by whole-body inhalation to 0, 25, or 100 ppm MeI, 6 h/day for up to 2 days. Serum cholesterol concentrations (both high-density lipoprotein [HDL] and low-density lipoprotein [LDL] fractions) were increased and triglycerides were decreased at both exposure levels. Serum thyroid-stimulating hormone (TSH) concentrations were increased at 25 and 100 ppm, and serum triiodothyronine (T(3)) and thyroxine (T(4)) concentrations were decreased at 100 ppm. There was no change in either reverse triiodothyronine (rT(3)) or UDP-glucuronyltransferase activity at either exposure level. A dose- and time-dependent reduction in GSH levels in blood, kidney, liver, and nasal tissue was observed, with t...
Genome-wide gene expression profiling has become standard for assessing potential liabilities as ... more Genome-wide gene expression profiling has become standard for assessing potential liabilities as well as for elucidating mechanisms of toxicity of drug candidates under development. Analysis of microarray data is often challenging due to the lack of a statistical model that is amenable to biological variation in a small number of samples. Here we present a novel non-parametric algorithm that requires minimal assumptions about the data distribution. Our method for determining differential expression consists of two steps: 1) We apply a nominal threshold on fold change and platform p-value to designate whether a gene is differentially expressed in each treated and control sample relative to the averaged control pool, and 2) We compared the number of samples satisfying criteria in step 1 between the treated and control groups to estimate the statistical significance based on a null distribution established by sample permutations. The method captures group effect without being too sensi...
Gene expression profiling is a tool to gain mechanistic understanding of adverse effects in respo... more Gene expression profiling is a tool to gain mechanistic understanding of adverse effects in response to compound exposure. However, little is known about how the common handling procedures of experimental animals during a preclinical study alter baseline gene expression. We report gene expression changes in the livers of female Sprague-Dawley rats following common handling procedures. Baseline gene expression changes identified in this study provide insight on how these changes may affect interpretation of gene expression profiles following compound exposure. Rats were divided into three groups. One group was not subjected to handling procedures and served as controls for both handled groups. Animals in the other two groups were weighed, subjected to restraint in Broome restrainers, and administered water via oral gavage daily for 1 or 4 days with tail vein blood collections at 1, 2, 4, and 8 hours postdose on days 1 and 4. Significantly altered genes were identified in livers of an...
The purpose of this study was to compare the toxicity of linear/branched ammonium perfluorooctano... more The purpose of this study was to compare the toxicity of linear/branched ammonium perfluorooctanoate (APFO) with that of linear and branched APFO. Linear/branched APFO (approximately 80% linear and 20% branched isomers) was formerly used in the production of commercial products. The extensive toxicologic database for APFO has been developed essentially using this mixture of isomers. The trend now is to use APFO containing only the linear isomer. The current study was performed to determine if the toxicological database developed for the linear/branched isomer is applicable to the linear isomer. To determine the contribution of branched APFO to the toxicity of linear/branched APFO, a form of APFO that was 100% branched was synthesized. Rats and mice were given doses by oral gavage ranging from 0.3 to 30 mg/kg of either the linear/branched, linear, or branched APFO for 14 days. Clinical signs, body weights, food consumption, selected hematology and serum lipid parameters, liver and kidney weights, hepatic peroxisomal beta-oxidation, and serum PFOA concentrations were evaluated. Mean body weights were about 20% lower in rats and mice dosed with 30 mg/kg of linear/branched or linear APFO compared to controls, and 3-5% lower in animals dosed with 30 mg/kg of branched APFO. In rats, all three forms reduced lipids. In mice, all three forms reduced total and HDL cholesterol similarly but triglycerides were increased at lower doses. Increased peroxisomal beta-oxidation activity and serum PFOA concentrations were seen in both species but these effects were least pronounced in rats dosed with the branched material. In rats, serum PFOA levels were 20-51 ppm at Lowest Observed Effect Levels (LOEL) of 0.3-1 mg/kg, based primarily upon lipid parameters. In mice, serum PFOA levels were 10-14 ppm at the LOEL of 0.3 mg/kg, based primarily upon relative liver weight. In both rats and mice, the overall responses to the linear/branched and the linear forms of PFOA were similar, but the branched form appears to be less potent. Based on these results, and for the endpoints evaluated in this study, the toxicological database developed primarily from testing linear/branched APFO is applicable to linear APFO.
Intracardiac injection of human tumor cells into anesthetized nude mice is an established model o... more Intracardiac injection of human tumor cells into anesthetized nude mice is an established model of bone metastasis. However, intracardiac injection of some human tumor cell lines cause acute neurologic signs and high mortality, making some potentially relevant tumor cell lines unusable for investigation. We showed that intracardiac injection of tumor cells can induce a hypercoagulable state leading to platelet consumption and thromboemboli formation and that pretreatment with intravenous injection of low-molecular-weight heparin (LMWH; enoxaparin) blocks this state. In addition, intravenous injection of enoxaparin before intracardiac injection with 2 different small-cell lung carcinoma lines, H1975 and H2126, dramatically decreased mouse mortality while still generating bone metastases. Therefore, reduction of mortality by pretreatment with LMWH increases the types of cells that can be studied in this metastasis model and decreases the number of animals used.
Toxicological sciences : an official journal of the Society of Toxicology, 2014
The dysregulation of phosphatidylinositol 3-kinase (PI3K)-dependent pathways is implicated in sev... more The dysregulation of phosphatidylinositol 3-kinase (PI3K)-dependent pathways is implicated in several human cancers making it an attractive target for small molecule PI3K inhibitors. A series of potent pyridyltriazine-containing inhibitors of class Ia PI3Ks were synthesized and a subset of compounds was evaluated in exploratory repeat-dose rat toxicology studies. Daily oral dosing of compound 1: in Sprague Dawley rats for four consecutive days was associated with hepatobiliary toxicity that included biliary epithelial hyperplasia and hypertrophy, periductular edema, biliary stasis, and acute peribiliary inflammatory infiltrates. These histological changes were associated with clinical pathology changes that included increased serum liver enzymes, total bile acids, and bilirubin. The predominant clearance pathway of 1: was shown in vitro and in a bile-duct cannulated rat (14)C-ADME study to be P450-mediated oxidative metabolism. An O-demethylated pyridine metabolite, M3: , was identi...
Bioorganic & medicinal chemistry letters, Jan 8, 2015
The β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is one of the most hotly pur... more The β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is one of the most hotly pursued targets for the treatment of Alzheimer's disease. We used a structure- and property-based drug design approach to identify 2-aminooxazoline 3-azaxanthenes as potent BACE1 inhibitors which significantly reduced CSF and brain Aβ levels in a rat pharmacodynamic model. Compared to the initial lead 2, compound 28 exhibited reduced potential for QTc prolongation in a non-human primate cardiovascular safety model.
The Ascensia ENTRUST blood glucose meter is intended for self-monitoring of blood glucose by diab... more The Ascensia ENTRUST blood glucose meter is intended for self-monitoring of blood glucose by diabetic patients. Use of such a glucometer would minimize blood volume requirements for the measurement of glucose in small laboratory animals. The purpose of this study was to assess the performance of the Ascensia ENTRUST for measuring glucose in whole blood from Wistar rats by evaluating the effect of anticoagulant and sample processing delay and comparing normalized results with plasma glucose concentration. Blood samples were collected from the retroorbital sinus of 30 male Wistar rats with a wide range of blood glucose concentrations. Glucose concentration was measured with the Ascensia ENTRUST in nonheparinized (NH) and heparinized samples immediately after collection (Hep-0) and in heparinized samples after a 15 min delay at 23-28 degrees C (Hep-15). Heparinized samples were centrifuged and glucose concentration was determined in plasma using an automated chemistry analyzer. Results were compared to assess the effect of anticoagulant (NH vs Hep-0) and time (Hep 0 vs Hep 15), and to compare normalized Hep-15 results with plasma glucose concentration. Glucose concentration was not significantly different between NH and Hep-0 samples. Glucose concentration was lower in Hep-15 (77+/-36.9 mg/dL) than Hep-0 (88+/-39.7 mg/dL) samples, but the difference was not significant. With normalization, Hep-15 glucose concentration correlated well (r>or=.98) with plasma glucose concentration but was lower by 6.0+/-16.7 mg/dL, with a positive bias at low glucose concentrations and a negative bias at high concentrations. The Ascensia ENTRUST may be adequate for repeated blood glucose measurements in rats, but its results do not accurately predict plasma glucose concentrations measured by an automated clinical chemistry analyzer.
Most published reviews of preclinical toxicological clinical pathology focus on the fundamental a... more Most published reviews of preclinical toxicological clinical pathology focus on the fundamental aspects of hematology, clinical chemistry, coagulation, and urinalysis in routine toxicology animal species, for example, rats, mice, dogs, and nonhuman primates. The objective of this continuing education course was to present and discuss contemporary examples of nonroutine applications of clinical pathology endpoints used in the drug development setting. Area experts discussed bone turnover markers of laboratory animal species, clinical pathology of pregnant and growing laboratory animals, clinical pathology of nonroutine laboratory animal species, and unique applications of the Siemens Advia(®) hematology analyzer. This article is a summary based on a presentation given at the 31st Annual Symposium of the Society of Toxicologic Pathology, during the Continuing Education Course titled "Nontraditional Applications of Clinical Pathology in Drug Discovery and Preclinical Toxicology."
A combined repeated-dose toxicity study with reproduction was conducted with 2-pentenenitrile (2-... more A combined repeated-dose toxicity study with reproduction was conducted with 2-pentenenitrile (2-PN). Rats (10/sex per dose level) were dosed with 2-PN once daily by gavage at dose levels of either 0, 1, 3, or 10 mg kg(-1) day(-1) for 28 days, prior to and during cohabitation, and through day 3 of lactation. General clinical observations were recorded daily; body weights were recorded weekly. A neurobehavioral evaluation consisting of a functional observational battery and motor activity was conducted in all parental rats (10/sex per group). Clinical pathology parameters (hematology, clinical chemistry, coagulation) were measured in parental rats. Pup weights and clinical signs were recorded at birth and on lactation day 4. Parental rats were given a gross pathological examination, organ weights were obtained, and histological examination was conducted for the control and 10 mg kg(-1) day(-1) groups. No effects were seen with regard to mortality, clinical signs, functional observational battery and motor activity, hematology, or organ weights. Females receiving 10 mg/kg and males from all dose groups showed lower body weight gains and feed efficiency. Increased albumin concentrations were seen in both sexes given 10 mg/kg. Females in the 10 mg/kg group showed degeneration of the olfactory mucosa. No effects on the numbers of pups born, number surviving to lactation day 4, pup weight, and no gross anatomical development changes were observed. Under the conditions of this study, the no-observed-effect level (NOEL) for systemic toxicity in rats was 3 mg kg(-1) day(-1), based on degeneration of olfactory mucosa in females at 10 mg kg(-1) day(-1). The NOEL for reproductive and neurobehavioral toxicity in rats and for toxicity to offspring was 10 mg kg(-1) day(-1), the highest dose level tested.
The diverse functions of thyroid hormone (T3) are presumed to be mediated by two genes encoding t... more The diverse functions of thyroid hormone (T3) are presumed to be mediated by two genes encoding the related receptors, TRalpha and TRbeta. However, the in vivo functions of TRalpha and TRbeta are undefined. Here, we report that targeted inactivation of the mouse TRbeta gene results in goitre and elevated levels of thyroid hormone. Also, thyroid-stimulating hormone (TSH), which is released by pituitary thyrotropes and which is normally suppressed by increased levels of thyroid hormone, was present at elevated levels in homozygous mutant (Thrb-/-) mice. These findings suggest a unique role for TRbeta that cannot be substituted by TRalpha in the T3-dependent feedback regulation of TSH transcription. Thrb-/- mice provide a recessive model for the human syndrome of resistance to thyroid hormone (RTH) that exhibits a similar endocrine disorder but which is typically caused by dominant TRbeta mutants that are transcriptional inhibitors. It is unknown whether TRalpha, TRbeta or other recept...
The effects of inhaled methyl iodide (MeI) on clinical pathology parameters, glutathione (GSH) ti... more The effects of inhaled methyl iodide (MeI) on clinical pathology parameters, glutathione (GSH) tissue levels, serum thyroid hormone and inorganic iodide concentrations, S-methylcysteine hemoglobin concentrations, and liver UDP-glucuronyltransferase activity were studied in the rat. Male rats were exposed by whole-body inhalation to 0, 25, or 100 ppm MeI, 6 h/day for up to 2 days. Serum cholesterol concentrations (both high-density lipoprotein [HDL] and low-density lipoprotein [LDL] fractions) were increased and triglycerides were decreased at both exposure levels. Serum thyroid-stimulating hormone (TSH) concentrations were increased at 25 and 100 ppm, and serum triiodothyronine (T(3)) and thyroxine (T(4)) concentrations were decreased at 100 ppm. There was no change in either reverse triiodothyronine (rT(3)) or UDP-glucuronyltransferase activity at either exposure level. A dose- and time-dependent reduction in GSH levels in blood, kidney, liver, and nasal tissue was observed, with t...
Genome-wide gene expression profiling has become standard for assessing potential liabilities as ... more Genome-wide gene expression profiling has become standard for assessing potential liabilities as well as for elucidating mechanisms of toxicity of drug candidates under development. Analysis of microarray data is often challenging due to the lack of a statistical model that is amenable to biological variation in a small number of samples. Here we present a novel non-parametric algorithm that requires minimal assumptions about the data distribution. Our method for determining differential expression consists of two steps: 1) We apply a nominal threshold on fold change and platform p-value to designate whether a gene is differentially expressed in each treated and control sample relative to the averaged control pool, and 2) We compared the number of samples satisfying criteria in step 1 between the treated and control groups to estimate the statistical significance based on a null distribution established by sample permutations. The method captures group effect without being too sensi...
Gene expression profiling is a tool to gain mechanistic understanding of adverse effects in respo... more Gene expression profiling is a tool to gain mechanistic understanding of adverse effects in response to compound exposure. However, little is known about how the common handling procedures of experimental animals during a preclinical study alter baseline gene expression. We report gene expression changes in the livers of female Sprague-Dawley rats following common handling procedures. Baseline gene expression changes identified in this study provide insight on how these changes may affect interpretation of gene expression profiles following compound exposure. Rats were divided into three groups. One group was not subjected to handling procedures and served as controls for both handled groups. Animals in the other two groups were weighed, subjected to restraint in Broome restrainers, and administered water via oral gavage daily for 1 or 4 days with tail vein blood collections at 1, 2, 4, and 8 hours postdose on days 1 and 4. Significantly altered genes were identified in livers of an...
The purpose of this study was to compare the toxicity of linear/branched ammonium perfluorooctano... more The purpose of this study was to compare the toxicity of linear/branched ammonium perfluorooctanoate (APFO) with that of linear and branched APFO. Linear/branched APFO (approximately 80% linear and 20% branched isomers) was formerly used in the production of commercial products. The extensive toxicologic database for APFO has been developed essentially using this mixture of isomers. The trend now is to use APFO containing only the linear isomer. The current study was performed to determine if the toxicological database developed for the linear/branched isomer is applicable to the linear isomer. To determine the contribution of branched APFO to the toxicity of linear/branched APFO, a form of APFO that was 100% branched was synthesized. Rats and mice were given doses by oral gavage ranging from 0.3 to 30 mg/kg of either the linear/branched, linear, or branched APFO for 14 days. Clinical signs, body weights, food consumption, selected hematology and serum lipid parameters, liver and kidney weights, hepatic peroxisomal beta-oxidation, and serum PFOA concentrations were evaluated. Mean body weights were about 20% lower in rats and mice dosed with 30 mg/kg of linear/branched or linear APFO compared to controls, and 3-5% lower in animals dosed with 30 mg/kg of branched APFO. In rats, all three forms reduced lipids. In mice, all three forms reduced total and HDL cholesterol similarly but triglycerides were increased at lower doses. Increased peroxisomal beta-oxidation activity and serum PFOA concentrations were seen in both species but these effects were least pronounced in rats dosed with the branched material. In rats, serum PFOA levels were 20-51 ppm at Lowest Observed Effect Levels (LOEL) of 0.3-1 mg/kg, based primarily upon lipid parameters. In mice, serum PFOA levels were 10-14 ppm at the LOEL of 0.3 mg/kg, based primarily upon relative liver weight. In both rats and mice, the overall responses to the linear/branched and the linear forms of PFOA were similar, but the branched form appears to be less potent. Based on these results, and for the endpoints evaluated in this study, the toxicological database developed primarily from testing linear/branched APFO is applicable to linear APFO.
Intracardiac injection of human tumor cells into anesthetized nude mice is an established model o... more Intracardiac injection of human tumor cells into anesthetized nude mice is an established model of bone metastasis. However, intracardiac injection of some human tumor cell lines cause acute neurologic signs and high mortality, making some potentially relevant tumor cell lines unusable for investigation. We showed that intracardiac injection of tumor cells can induce a hypercoagulable state leading to platelet consumption and thromboemboli formation and that pretreatment with intravenous injection of low-molecular-weight heparin (LMWH; enoxaparin) blocks this state. In addition, intravenous injection of enoxaparin before intracardiac injection with 2 different small-cell lung carcinoma lines, H1975 and H2126, dramatically decreased mouse mortality while still generating bone metastases. Therefore, reduction of mortality by pretreatment with LMWH increases the types of cells that can be studied in this metastasis model and decreases the number of animals used.
Toxicological sciences : an official journal of the Society of Toxicology, 2014
The dysregulation of phosphatidylinositol 3-kinase (PI3K)-dependent pathways is implicated in sev... more The dysregulation of phosphatidylinositol 3-kinase (PI3K)-dependent pathways is implicated in several human cancers making it an attractive target for small molecule PI3K inhibitors. A series of potent pyridyltriazine-containing inhibitors of class Ia PI3Ks were synthesized and a subset of compounds was evaluated in exploratory repeat-dose rat toxicology studies. Daily oral dosing of compound 1: in Sprague Dawley rats for four consecutive days was associated with hepatobiliary toxicity that included biliary epithelial hyperplasia and hypertrophy, periductular edema, biliary stasis, and acute peribiliary inflammatory infiltrates. These histological changes were associated with clinical pathology changes that included increased serum liver enzymes, total bile acids, and bilirubin. The predominant clearance pathway of 1: was shown in vitro and in a bile-duct cannulated rat (14)C-ADME study to be P450-mediated oxidative metabolism. An O-demethylated pyridine metabolite, M3: , was identi...
Bioorganic & medicinal chemistry letters, Jan 8, 2015
The β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is one of the most hotly pur... more The β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is one of the most hotly pursued targets for the treatment of Alzheimer's disease. We used a structure- and property-based drug design approach to identify 2-aminooxazoline 3-azaxanthenes as potent BACE1 inhibitors which significantly reduced CSF and brain Aβ levels in a rat pharmacodynamic model. Compared to the initial lead 2, compound 28 exhibited reduced potential for QTc prolongation in a non-human primate cardiovascular safety model.
The Ascensia ENTRUST blood glucose meter is intended for self-monitoring of blood glucose by diab... more The Ascensia ENTRUST blood glucose meter is intended for self-monitoring of blood glucose by diabetic patients. Use of such a glucometer would minimize blood volume requirements for the measurement of glucose in small laboratory animals. The purpose of this study was to assess the performance of the Ascensia ENTRUST for measuring glucose in whole blood from Wistar rats by evaluating the effect of anticoagulant and sample processing delay and comparing normalized results with plasma glucose concentration. Blood samples were collected from the retroorbital sinus of 30 male Wistar rats with a wide range of blood glucose concentrations. Glucose concentration was measured with the Ascensia ENTRUST in nonheparinized (NH) and heparinized samples immediately after collection (Hep-0) and in heparinized samples after a 15 min delay at 23-28 degrees C (Hep-15). Heparinized samples were centrifuged and glucose concentration was determined in plasma using an automated chemistry analyzer. Results were compared to assess the effect of anticoagulant (NH vs Hep-0) and time (Hep 0 vs Hep 15), and to compare normalized Hep-15 results with plasma glucose concentration. Glucose concentration was not significantly different between NH and Hep-0 samples. Glucose concentration was lower in Hep-15 (77+/-36.9 mg/dL) than Hep-0 (88+/-39.7 mg/dL) samples, but the difference was not significant. With normalization, Hep-15 glucose concentration correlated well (r>or=.98) with plasma glucose concentration but was lower by 6.0+/-16.7 mg/dL, with a positive bias at low glucose concentrations and a negative bias at high concentrations. The Ascensia ENTRUST may be adequate for repeated blood glucose measurements in rats, but its results do not accurately predict plasma glucose concentrations measured by an automated clinical chemistry analyzer.
Most published reviews of preclinical toxicological clinical pathology focus on the fundamental a... more Most published reviews of preclinical toxicological clinical pathology focus on the fundamental aspects of hematology, clinical chemistry, coagulation, and urinalysis in routine toxicology animal species, for example, rats, mice, dogs, and nonhuman primates. The objective of this continuing education course was to present and discuss contemporary examples of nonroutine applications of clinical pathology endpoints used in the drug development setting. Area experts discussed bone turnover markers of laboratory animal species, clinical pathology of pregnant and growing laboratory animals, clinical pathology of nonroutine laboratory animal species, and unique applications of the Siemens Advia(®) hematology analyzer. This article is a summary based on a presentation given at the 31st Annual Symposium of the Society of Toxicologic Pathology, during the Continuing Education Course titled "Nontraditional Applications of Clinical Pathology in Drug Discovery and Preclinical Toxicology."
Uploads
Papers by Nancy Everds