Pharmacy and Pharmaceutical Sciences Commons^™

An Overview Of The Role Of Mathematical Models In Implementation Of Quality By Design Paradigm For Drug Development And Manufacture, Sharmista Chatterjee, Christine M.V. Moore, Moheb M. Nasr

Food and Drug Administration Papers

A model is a representation of an underlying physical–chemical phenomenon. In the pharmaceutical industry, mathematical‐based models can be applied at all stages of development, starting with formulation design, continuing through process development and scale‐up, and extending into process monitoring and control of the commercial process. Implementation of models offers many benefits. These include, but are not limited to, (i) enhanced process understanding, (ii) reduction of experimentation cost, and (iii) improvement of productivity and product quality.

Models can be broadly categorized as either qualitative or quantitative. The focus of this chapter is quantitative models. These can be classified into three broad …

Modeling And Statistical Issues Related To Salmonella In Low Water Activity Foods, Sofia M. Santillana Farakos, Michelle Danyluk, Donald Schaffner, Régis Pouillot, Linda J. Harris, Bradley P. Marks

Food and Drug Administration Papers

The presence and survival of Salmonella in low water activity (a_w) foods continues to pose a challenge for the food industry. Peer‐reviewed literature data on prevalence and levels of contamination of Salmonella in low water activity foods in the United States are limited. Available published data include those on: Salmonella contamination on nuts and peanuts (Calhoun et al., 2013), almonds (Danyluk et al., 2007; Bansal et al., 2010), pecans (Brar, Strawn, and Danyluk, 2016), and walnuts (Davidson et al., 2015); prevalence and levels of Salmonella on spices (Van Doren et al., 2013); as …

The Mechanism Of Cirp In Inhibition Of Keratinocytes Growth Arrest And Apoptosis Following Low Dose Uvb Radiation, Yi Liao, Jianguo Feng, Yi Zhang, Liling Tang, Shiyong Wu

Food and Drug Administration Papers

UV induces CIRP expression and subsequent Stat3 activation, but the biological function and mechanism of CIRP and Stat3 in mediating UVB-induced skin carcinogenesis have not been fully elucidated. In this study, we demonstrate that CIRP is elevated in all tested melanoma and non-melanoma skin cancer cell lines; and the expression of CIRP is upregulated in keratinocytes after being irradiated with relatively low dose (<5 mJ/cm²), but not high dose (50 mJ/cm²), UVB acutely and chronically. The increased expression of CIRP, either induced by UVB or through overexpression, leads to resistance of keratinocytes to UVB-induced growth arrest and …

High Throughput Quantification Of Apolipoproteins A-I And B-100 By Isotope Dilution Ms Targeting Fast Trypsin Releasable Peptides Without Reduction And Alkylation, Bryan A. Parks, David M. Schieltz, Michael L. Andrews, Michael S. Gardner, John C. Rees, Christopher A. Toth, Jeffrey I. Jones, Lisa G. Mcwilliams, Zsuzsanna Kuklenyik, James L. Pirkle, John R. Barr

Food and Drug Administration Papers

Purpose: Apolipoprotein A-I (ApoA-I) and apolipoprotein B-100 (ApoB-100) are amphipathic proteins that are strong predictors of cardiovascular disease risk. The traceable calibration of apolipoprotein assays is a persistent challenge, especially for ApoB-100, which cannot be solubilized in purified form.

Experimental design: A simultaneous quantitation method for ApoA-I and ApoB-100 was developed using tryptic digestion without predigestion reduction and alkylation, followed by LC separation coupled with isotope dilution MS analysis. The accuracy of the method was assured by selecting structurally exposed signature peptides, optimal choice of detergent, protein: enzyme ratio, and incubation time. Peptide calibrators were value assigned by isobaric tagging …

Cyclosporine Exacerbates Ketamine Toxicity In Zebrafish: Mechanistic Studies On Drug–Drug Interaction, Bonnie L. Robinson, Melanie Dumas, Syed F. Ali, Merle G. Paule, Qiang Gu, Jyotshna Kanungo

Food and Drug Administration Papers

Cyclosporine A (CsA) is an immunosuppressive drug commonly used in organ transplant patients to prevent allograft rejections. Ketamine is a pediatric anesthetic that noncompetitively inhibits the calcium-permeable N-methyl-D-aspartic acid receptors. Adverse drug–drug interaction effects between ketamine and CsA have been reported in mammals and humans. However, the mechanism of such drug–drug interaction is unclear. We have previously reported adverse effects of combination drugs, such as verapamil/ketamine and shown the mechanism through intervention by other drugs in zebrafish embryos. Here, we show that ketamine and CsA in combination produce developmental toxicity even leading to lethality in zebrafish larvae when exposure began …

Rapid Testing Of Food Matrices For Bacillus Cereus Enterotoxins, Sandra M. Tallent, Jennifer M. Hait, Ann M. Knolhoff, Reginald W. Bennett, Thomas S. Hammack, Timothy R. Croley

Food and Drug Administration Papers

Nine different food products frequently associated with Bacillus cereus outbreaks were chosen as representative matrices to be evaluated with end-point polymerase chain reaction (PCR), enzyme linked immunosorbent assay, lateral flow device and mass spectrometry for detection of enterotoxins associated with human illness. Testing was performed on food portions inoculated with a bacterial strain and incubated at 30C for either 5 h or 24 h. A screening end-point multiplex PCR targeting enterotoxin genes including the emetic toxin and three diarrheal toxins, hemolytic hemolysin BL (Hbl), nonhemoltyic enterotoxin (Nhe), and cytolysin K. Commercially available kits were used to determine the presence/absence of …

Variation In Organ-Specific Pik3ca And Kras Mutant Levels In Normal Human Tissues Correlates With Mutation Prevalence In Corresponding Carcinomas, Barbara L. Parsons, Karen L. Mckim, Meagan B. Myers

Food and Drug Administration Papers

Large-scale sequencing efforts have described the mutational complexity of individual cancers and identified mutations prevalent in different cancers. As a complementary approach, allele specific competitive blocker PCR (ACB-PCR) is being used to quantify levels of hotspot cancer driver mutations (CDMs) with high sensitivity, to elucidate the tissue-specific properties of CDMs, their occurrence as tumor cell subpopulations, and their occurrence in normal tissues. Here we report measurements of PIK3CA H1047R mutant fraction (MF) in normal colonic mucosa, normal lung, colonic adenomas, colonic adenocarcinomas, and lung adenocarcinomas. We report PIK3CA E545K MF measurements in those tissues, as well as in normal breast, …

Cannabinoid Disposition In Oral Fluid After Controlled Smoked, Vaporized, And Oral Cannabis Administration, Madeleine J. Swortwood, Matthew N. Newmeyer, Maria Andersson, Osama A. Abulseoud, Karl B. Scheidweiler, Marilyn A. Huestis

Food and Drug Administration Papers

Oral fluid (OF) is an important matrix for monitoring drugs. Smoking cannabis is common, but vaporization and edible consumption also are popular. OF pharmacokinetics are available for controlled smoked cannabis, but few data exist for vaporized and oral routes. Frequent and occasional cannabis smokers were recruited as participants for four dosing sessions including one active (6.9% Δ⁹-tetrahydrocannabinol, THC) or placebo cannabis-containing brownie, followed by one active or placebo cigarette, or one active or placebo vaporized cannabis dose. Only one active dose was administered per session. OF was collected before and up to 54 (occasional) or 72 (frequent) h …

Recent Analytical Methods For The Analysis Of Sweeteners In Food: A Regulatory Perspective, Romina Shah, Lowri S. De Jager

Food and Drug Administration Papers

Non-nutritive or low calorie sweeteners are commonly used worldwide in the food industry, often in combination in order to limit undesirable tastes. The list of allowable sweeteners varies among countries and it is important for regulatory agencies and food safety laboratories to monitor these highly consumed products to ensure compliance with worldwide regulations. Current analytical methods for confirmation and quantification of sweeteners must allow for confirmation of analyte identity in order to be compatible with today’s standards. Various methods for the determination of non-nutritive sweeteners have been reported in the literature. Th e most common multi-sweetener methods involve high performance …

Detection Of Allergen Markers In Food: Analytical Methods, Girdhari M. Sharma, Sefat E. Khuda, Christine H. Parker, Anne C. Eischeid, Marion Pereira

Food and Drug Administration Papers

Food allergens are proteins that are well tolerated by most, but can cause severe reactions in sensitive individuals. Since there is no cure for food allergy, strict adherence to an allergen-free diet is the only safe choice currently available for allergic consumers. Accurate food labeling can help consumers avoid foods containing an allergenic ingredient. Regulatory agencies have mandated the labeling of major food allergens on packaged foods to help with safe food choices. However, the inadvertent presence of an allergen in food due to cross-contact and labeling error can jeopardize consumer health. Analytical methods are developed for allergen detection and …

Current Analytical Techniques For Food Lipids, Cynthia T. Srigley, Magdi M. Mossoba

Food and Drug Administration Papers

Thee analysis of food lipids presents significant challenges due to the wide variety of sample matrices, large range of total fat contents, and complex compositions of fatty acids. This is chapter reviews conventional analytical techniques for the quantification of total fat and fatty acids in foods and food ingredients, including the gravimetric determination of total fat, the calculation of fat and fatty acids using gas chromatography (GC), and the analysis of proximates content (i.e., fat, protein, carbohydrate, moisture, and ash) by Fourier transform infrared (FTIR) spectroscopy. Current official methods of analysis are evaluated and the use of certified reference materials …

Multiple Imputation To Evaluate The Impact Of An Assay Change In National Surveys, Maya Sternberg

Food and Drug Administration Papers

National health surveys, such as the National Health and Nutrition Examination Survey, are used to monitor trends of nutritional biomarkers. These surveys try to maintain the same biomarker assay over time, but there are a variety of reasons why the assay may change. In these cases, it is important to evaluate the potential impact of a change so that any observed fluctuations in concentrations over time are not confounded by changes in the assay. To this end, a subset of stored specimens previously analyzed with the old assay is retested using the new assay. These paired data are used to …

Antiemetic Use Among Pregnant Women In The United States: The Escalating Use Of Ondansetron, Lockwood G. Taylor, Steven T. Bird, Leyla Sahin, Melissa S. Tassinari, Patty Greene, Marsha E. Reichman, Susan E. Andrade, Katherine Haffenreffer, Sengwee Toh

Food and Drug Administration Papers

Purpose To examine ondansetron use in pregnancy in the context of other antiemetic use among a large insured United States population of women delivering live births.

Methods We assessed ondansetron and other antiemetic use among pregnant women delivering live births between 2001 and 2015 in 15 data partners contributing data to the Mini-Sentinel Distributed Database. We identified live birth pregnancies using a validated algorithm, and all forms of ondansetron and other available antiemetics were identified using National Drug Codes or procedure codes. We assessed the prevalence of antiemetic use by trimester, calendar year, and formulation.

Results In over 2.3 million …

Certain Dyes As Pharmacologically Active Substances In Fish Farming And Other Aquaculture Products, Eric Verdon, Wendy C. Andersen

Food and Drug Administration Papers

The last 40 years have brought enormous changes to the aquaculture industry. The farming of fish and of seafood products has been continuously increasing from 3.9% by weight in 1970 to 36% in 2006 according to theWorld Health Organization (WHO) and Food and Agriculture Organization (FAO) of the United Nations.¹ The global trend of aquaculture development gaining importance in total fish supply has remained uninterrupted. Farmed food fish contributed a record 42.2% of the total 158 million tonnes of fish produced by capture fisheries and aquaculture in 2012 (Figure 9.1). This compares with just 13.4% in 1990 and 25.7% …

Color And Power Doppler Combined With Fetal Intelligent Navigation Echocardiography (Fine) To Evaluate The Fetal Heart, L. Yeo, R. Romero

Food and Drug Administration Papers

Objective To evaluate the performance of color and bidirectional power Doppler ultrasound combined with Fetal Intelligent Navigation Echocardiography (FINE) in examining the fetal heart.

Methods A prospective cohort study was conducted of fetuses in the second and third trimesters with a normal heart or with congenital heart disease (CHD). One or more spatiotemporal image correlation (STIC) volume datasets, combined with color or bidirectional power Doppler (S-flow) imaging, were acquired in the apical four-chamber view. Each successfully obtained STIC volume was evaluated by STICLoop™ to determine its appropriateness before applying the FINE method. Visualization rates for standard fetal echocardiography views using …

The Impact Of The Boxed Warning On The Duration Of Use For Depot Medroxprogesterone Acetate, Efe Eworuke, Joo-Yeon Lee, Lisa Soule, Vaishali Popat, David G. Moeny

Food and Drug Administration Papers

Objective The objective of this study was to examine the impact of the Food and Drug Administration’s boxed warning on the utilization of depot medroxyprogesterone (DMPA).

Methods From the IMS Lifelink data (2001–2009), we identified DMPA and oral combined hormonal contraceptive (CHC) users without a prescription claim 6 months before and after the first and last claim. Episodes were defined as all contiguous claims with no more than 90- day DMPA or 30-day CHC between claims. Days’ supply (CHC) and 90-day duration (DMPA) was used to determine episodes. We used interrupted time series to evaluate changes in the mean episode …

Disparities In Hypertension And Cardiovascular Disease In Blacks: The Critical Role Of Medication Adherence, Keith C. Ferdinand, Kapil Yadav, Samar A. Nasser, Helene D. Clayton-Jeter, John Lewin, Dennis R. Cryer, Fortunato Fred Senatore

Food and Drug Administration Papers

Blacks are two to three times as likely as whites to die of preventable heart disease and stroke. Declines in mortality from heart disease have not eliminated racial disparities. Control and effective treatment of hypertension, a leading cause of cardiovascular disease, among blacks is less than in whites and remains a challenge. One of the driving forces behind this racial/ethnic disparity is medication nonadherence whose cause is embedded in social determinants. Eight practical approaches to addressing medication adherence with the potential to attenuate disparities were identified and include: (1) patient engagement strategies, (2) consumer-directed health care, (3) patient portals, (4) …

Current Practices In Corrosion, Surface Characterization, And Nickel Leach Testing Of Cardiovascular Metallic Implants, Srinidhi Nagaraja, Matthew Di Prima, David Saylor, Erica Takai

Food and Drug Administration Papers

In an effort to better understand current test practices and improve nonclinical testing of cardiovascular metallic implants, the Food and Drug Administration (FDA) held a public workshop on Cardiovascular Metallic Implants: corrosion, surface characterization, and nickel leaching. The following topics were discussed: (1) methods used for corrosion assessments, surface characterization techniques, and nickel leach testing of metallic cardiovascular implant devices, (2) the limitations of each of these in vitro tests in predicting in vivo performance, (3) the need, utility, and circumstances when each test should be considered, and (4) the potential testing paradigms, including acceptance criteria for each test. In …

Monitoring Harm Perceptions Of Smokeless Tobacco Products Among U.S. Adults: Health Information National Trends Survey 2012, 2014, 2015, Shari P. Feirman, Elisabeth A. Donaldson, Mark Parascandola, Kimberly Snyder, Cindy Tworek

Food and Drug Administration Papers

Introduction: Changes to the U.S. smokeless tobacco landscape in recent years include a change to health warnings on packages, the implementation of bans in some stadiums, and the launch of a federal youth pre- vention campaign. It is unclear whether such changes have impacted consumer beliefs about smokeless tobacco. This study examines relative harm perceptions of smokeless tobacco compared to cigarettes among adults and assesses changes in smokeless tobacco harm perceptions over time.

Methods: We analyzed data from three cycles (2012, 2014, 2015) of the Health Information National Trends Survey (HINTS). Using 2015 data, we assessed bivariate associations between smokeless …

Volumetry Of Low-Contrast Liver Lesions With Ct: Investigation Of Estimation Uncertainties In A Phantom Study, Qin Li, Yongguang Liang, Qiao Huang, Min Zong, Benjamin Berman, Marios A. Gavrielides, Lawrence H. Schwartz, Binsheng Zhao, Nicholas Petrick

Food and Drug Administration Papers

Purpose: To evaluate the performance of lesion volumetry in hepatic CT as a function of various imaging acquisition parameters.

Methods: An anthropomorphic abdominal phantom with removable liver inserts was designed for this study. Two liver inserts, each containing 19 synthetic lesions with varying diameter (6–40 mm), shape, contrast (10–65 HU), and both homogenous and mixed-density were designed to have background and lesion CT values corresponding to arterial and portal-venous phase imaging, respectively. The two phantoms were scanned using two commercial CT scanners (GE 750 HD and Siemens Biograph mCT) across a set of imaging protocols (four slice thicknesses, …

Investigation Of Tattoo Pigments By Raman Spectroscopy, Betsy Jean Yakes, Tara Jade Michael, Marianita Perez-Gonzalez, Bhakti Petigara Harp

Food and Drug Administration Papers

As a result of the increase in the practice of tattooing, the US Food and Drug Administration has identified a need for improved analytical methods to detect the pigments and potential impurities in the inks. Raman spectroscopy allows for nondestructive identification of compounds and is commonly used in art, archaeology, and forensics; however, the technique has only limitedly been applied to the identification of tattoo pigments. In this study, approximately 30 inorganic, organometallic, and organic pigmentswere evaluated with Raman spectroscopy by using 532, 633, and 780-nmlasers. Individual optimization of the instrumental parameters was performed for each pigment in order to …

Bacterial Endotoxin Detection In Hyaluronic Acid-Based Medical Devices, Larissa F. Baeva, Srilekha Sarkar Das, Victoria M. Hitchins

Food and Drug Administration Papers

A simple and rapid method has been developed for testing bacterial endotoxin in hyaluronic acid (HA)-based medical devices. High-molecular-weight HA (HMW HA) in solution or HA-based medical devices was digested by the enzyme hyaluronidase to reduce solution viscosity by truncating the long chains of HA and to test for bacterial endotoxin. The bacterial endotoxin level was detected and measured by kinetic chromogenic Limulus Amebocyte Lysate (LAL) assay. The method was applied to two different ophthalmic viscosurgical devices (OVDs) and one dermal filler, and may easily be adapted to use with up to 3% HA solutions and other HA-based medical devices.

Pharmacokinetics And Distribution In Interstitial And Pulmonary Epithelial Lining Fluid Of Danofloxacin In Ruminant And Preruminant Calves, D. A. Mzyk, R. E. Baynes, K. M. Messenger, M. Martinez, G. W. Smith

Food and Drug Administration Papers

The objective of this study was to compare active drug concentrations in the plasma vs. different effector compartments including interstitial fluid (ISF) and pulmonary epithelial lining fluid (PELF) of healthy preruminating (3-week-old) and ruminating (6-month-old) calves. Eight calves in each age group were given a single subcutaneous (s.c.) dose (8 mg/kg) of danofloxacin. Plasma, ISF, and bronchoalveolar lavage (BAL) fluid were collected over 96 h and analyzed by high-pressure liquid chromatography. PELF concentrations were calculated by a urea dilution assay of the BAL fluids. Plasma protein binding was measured using a microcentrifugation system. For most preruminant and ruminant calves, the …

Effects Of Repeated Quetiapine Treatment On Conditioned Avoidance Responding In Rats, Jun Gao, Min Feng, Natashia Swalve, Collin Davis, Nan Sui, Ming Li

Department of Psychology: Faculty Publications

The present study characterized the behavioral mechanisms of avoidance–disruptive effect of quetiapine in the conditioned avoidance response test under two behavioral testing (2 warning signals vs. 1 warning signal) and two drug administration conditions (subcutaneous vs. intravenous). In Experiments 1 and 2, well-trained adult male Sprague-Dawley rats were tested under the subcutaneous (s.c.) quetiapine treatment (5.0, 15.0, 25.0, 50.0 mg/kg) for 7 days in a novel procedure consisting of two conditioned stimuli (CS) (white noise serving as CS1 and pure tone as CS2). Only the highest dose (50.0 mg/kg) produced a persistent suppression of the avoidance response without impairing the …

Scientific And Regulatory Policy Committee (Srpc) Review*: Interpretation And Use Of Cell Proliferation Data In Cancer Risk Assessment, Charles E. Wood, Renee R. Hukkanen, Radhakrisha Sura, David Jacobson-Kram, Thomas Nolte, Marielle Odin, Samuel M. Cohen

Food and Drug Administration Papers

Increased cell proliferation is a central key event in the mode of action for many non-genotoxic carcinogens, and quantitative cell proliferation data play an important role in the cancer risk assessment of many pharmaceutical and environmental compounds. Currently, there is limited unified information on assay standards, reference values, targeted applications, study design issues, and quality control considerations for proliferation data. Here, we review issues in measuring cell proliferation indices, considerations for targeted studies, and applications within current risk assessment frameworks. As the regulatory environment moves toward more prospective evaluations based on quantitative pathway-based models, standardiza- tion of proliferation assays will …

Production Of Recombinant Human Coagulation Factor Ix By Transgenic Pig, Weijie Xu

Department of Chemical and Biomolecular Engineering: Theses and Student Research

Hemophilia B is the congenital bleeding disorder caused by deficiency in functional coagulation factor IX (FIX) and about 28,000 patients worldwide in 2012. And current treatment is restricted to protein-replacement therapy, which required FIX concentrates for patients’ life-time. Approximately 1 billion units FIX were consumed in 2012. However, still about 70-80% patients, mostly in developing countries, received inadequate or no treatment because of the unavailable and/or unaffordable FIX concentrates. Considering safety reasons, e.g. transmission of blood-borne diseases, the recombinant human FIX (rFIX) is recommended other than the plasma-derived FIX. However, only one rFIX is currently available on the market. The …

Environmental And Behavioral Controls Of The Expression Of Clozapine Tolerance: Evidence From A Novel Across-Model Transfer Paradigm, Min Feng, Nan Sui, Ming Li

Department of Psychology: Faculty Publications

Repeated administration of antipsychotic drugs induces a sensitization-like or tolerance-like effect in many behavioral tasks, including the conditioned avoidance response (CAR) and the phencyclidine (PCP)-induced hyperlocomotion, two rodent models with high predictive validity for antipsychotic activity. This study investigated the impacts of contextual and behavioral variables on the expression of clozapine tolerance using a recently validated across-model transfer paradigm (Zhang and Li, 2012). Male Sprague-Dawley rats were first repeatedly treated with clozapine (2.5–10.0 mg/kg, sc) in the CAR model or PCP (1.6 mg/kg, sc)-induced hyperlocomotion model for five consecutive days. They were then tested for the expression of clozapine tolerance …

Avoidance Disruptive Effect Of Clozapine And Olanzapine Is Potentiated By Increasing The Test Trials: Further Test Of The Motivational Salience Hypothesis, Min Feng, Nan Sui, Ming Li

Department of Psychology: Faculty Publications

Antipsychotic drugs suppress animals’ ability to avoid an aversive stimulus in the conditioned avoidance response model (CAR). This behavioral effect is thought to reflect antipsychotic activity and is suggested to be mediated by a drug’s action in attenuating the motivational salience of a conditioned stimulus (CS). In the present study, we tested whether atypical antipsychotic drugs clozapine and olanzapine act through this behavioral mechanism by manipulating the number of avoidance test trials. We reasoned that more CS trials in the present of clozapine or olanzapine would afford the drug more opportunities to decrease the motivational salience of the CS, thus …

Characterization Of Pasteurella Multocida Strains Isolated From Geese, Zsuzsanna Varga, Dmitriy V. Volokhov, Laszlo Stipkovits, Akos Thuma, Boglarka Sellyei, Tibor Magyar

Food and Drug Administration Papers

Phenotypic and genotypic diversity of forty-two Pasteurella multocida isolates from geese were characterized by analysis of their capsular type, Heddleston serotype, biotype, fimbrial gene allele type, comparative outer membrane protein (OMP) electrophoresis patterns, and were analyzed using PCR for the presence of virulence-associated genes (toxA, tbpA, pfhA, hgbA, hgbB, nanH, nanB, fimA, hsf-1, and pmHAS). A sequence comparison of the thdF and rpoB housekeeping genes of twenty representative P. multocida strains from three different OMP groups demonstrated that seventeen strains were closely related phylogenetically to previously published strains of P. multocida subsp. multocida and P. multocida subsp. gallicida, and only …

Differential Effects Of Acute Amphetamine And Phencyclidine Treatment And Withdrawal From Repeated Amphetamine Or Phencyclidine Treatment On Social Interaction And Social Memory In Rats, Ming Li, Wei He, Rebecca Munro

Department of Psychology: Faculty Publications

Although animal models based on amphetamine (AMPH) or phencyclidine (PCP) treatment have been used extensively to study the neurobiological and behavioral characteristics of schizophrenia, there are conflicting reports regarding their validity in modeling the negative symptoms and cognitive deficits of schizophrenia. The present study examined how acute AMPH or PCP treatment (Experiment 1) and withdrawal from repeated AMPH treatment (Experiment 2) or PCP treatment (Experiment 3) affects social behavior and social recognition memory in male Sprague-Dawley rats. Each subject was tested on two consecutive days. On the first day, the rats were tested four times (5 min/each) at 10-min intervals …