Development of a canine model to enable the preclinical assessment of pH-dependent absorption of test compounds.

A preclinical canine model capable of predicting a compound's potential for pH-dependent absorption in humans was developed. This involved the surgical insertion of a gastrostomy feeding tube into the stomach of a beagle dog. The tube was sutured in position to allow frequent withdrawal of gastric fluid for pH measurement. Therefore, it was possible to measure pH in the stomach and assess the effect of gastric pH-modifying agents on the absorption of various test compounds. Fasted gastric pH in the dog showed considerable inter- and intra-animal variability. Pretreatment of pentagastrin (6 µg/kg intramuscularly) 20 min prior to test compound administration was determined to be adequate for simulating fasting stomach pH in humans. Pretreatment with famotidine [40 mg orally] 1 h prior to test compound administration was determined to be adequate for simulating human gastric pH when acid-reducing agents are coadministered. Pentagastrin and famotidine pretreatments were used to test two discovery compounds and distinct differences in their potential for pH-dependent absorption were observed. The model described herein can be used preclinically to screen out compounds, differentiate compounds, and support the assessment of various formulation- and prodrug-based strategies to mitigate the pH effect.

Medical records for animals used in research, teaching, and testing: public statement from the American College of Laboratory Animal Medicine.

Medical records are considered to be a key element of a program of adequate veterinary care for animals used in research, teaching, and testing. However, prior to the release of the public statement on medical records by the American College of Laboratory Animal Medicine (ACLAM), the guidance that was available on the form and content of medical records used for the research setting was not consistent and, in some cases, was considered to be too rigid. To address this concern, ACLAM convened an ad hoc Medical Records Committee and charged the Committee with the task of developing a medical record guideline that was based on both professional judgment and performance standards. The Committee provided ACLAM with a guidance document titled Public Statements: Medical Records for Animals Used in Research, Teaching, and Testing, which was approved by ACLAM in late 2004. The ACLAM public statement on medical records provides guidance on the definition and content of medical records, and clearly identifies the Attending Veterinarian as the individual who is charged with authority and responsibility for oversight of the institution's medical records program. The document offers latitude to institutions in the precise form and process used for medical records but identifies typical information to be included in such records. As a result, the ACLAM public statement on medical records provides practical yet flexible guidelines to assure that documentation of animal health is performed in research, teaching, and testing situations.

The effect of chronic binge ethanol consumption on the primary stage of SIV infection in rhesus macaques.

BACKGROUND: Alcohol abuse and infection with HIV individually compromise immune function, but the consequence of both conditions together is poorly understood owing to the difficulties of performing appropriate studies in human subjects. Simian immunodeficiency virus (SIV) infection of rhesus macaques is considered to closely model HIV disease in that the virus infects CD4+ cells and this infection leads to a similar AIDS state. This study was initiated to study the combined effects of chronic binge alcohol consumption on the primary stage of SIV infection. METHODS: Rhesus macaques were administered alcohol or isocaloric sucrose via a permanently indwelling intragastric catheter 4 consecutive days per week for the duration of the study. Doses were individualized to achieve plasma alcohol concentrations of 50-60 mM over a 5-hr period. After 3 months, animals were inoculated intravenously with 10,000 times the ID(50) (50% infective dose) of SIV(DeltaB670) at the conclusion of an alcohol session and followed for 2 months postinoculation. RESULTS: At 1 week, plasma SIV RNA was greater than 60-fold higher in alcohol-consuming animals compared with sucrose controls. Likewise, alcohol consumption enhanced the SIV-induced increase in cell cycling T lymphocytes (i.e., cells expressing Ki67 protein) in blood. These differences between alcohol- and sucrose-treated animals were not sustained during the observation period. Peak viral load occurred 2 weeks post-SIV inoculation at 7.6 +/- 4.2 and 5.2 +/- 3.1 x 106 copies/ml in alcohol- versus sucrose-consuming animals, respectively. Blood CD4+ lymphocyte numbers were decreased 1 and 2 months after SIV inoculation to a similar degree in both sucrose-control and alcohol-treated animals. CONCLUSIONS: The consequence of the early rise in viral load and increase in lymphocyte turnover seen with excess alcohol consumption is unknown. We hypothesize that alcohol intoxication may increase the susceptibility of the host to HIV/SIV infection. This possibility needs to be explored further.