Inhibitors of arachidonic acid (AA) metabolism and other pharmacologic agents were evaluated against ear edema produced in mice by tetradecanoylphorbol acetate (TPA) or AA. Drugs were administered orally and topically either 30 min prior to AA or 30 min after TPA, except for steroids which were administered 2.5-3 hr prior to AA. Several cyclooxygenase (CO) inhibitors including indomethacin, aspirin, piroxicam and timegadine were without effect when administered orally against either irritant; the same drugs inhibited TPA edema when they were administered topically. Mixed CO/lipoxygenase (LO) inhibitors, phenidone and BW755C, were active orally against AA edema (ED50S of 84 and 65 mg/kg, respectively) and against TPA edema (ED50S of 235 and 88 mg/kg, respectively). Phenidone was more active topically against AA edema (ED50, 0.1 mg/ear) than BW755C (ED50, 2.8 mg/ear); however, BW755C was more active topically against TPA edema (ED50, 0.2 mg/ear) than phenidone (ED50, 0.6 mg/ear). Methylprednisolone was very effective in the AA (oral ED50, 17 mg/kg; topical ED50, greater than 1 mg/ear) and TPA models (oral ED50, 4.3 mg/kg; topical ED50, 0.03 mg/ear. MK-447 was topically and orally effective only in the TPA model. Not surprisingly, drugs were more effective topically than orally in both mouse ear edema assays. The models were somewhat selective for CO and CO/LO inhibitors; however, dapsone was orally effective in the ear models, and a number of mediator antagonists and CNS drugs, especially anti-psychotics, were topically active primarily against TPA edema. These models may be useful for the detection of in vivo activity of CO/LO or 5-LO inhibitors.
Intrauterine growth restriction (IUGR) is one of the key features of fetal alcohol syndrome (FAS), and IUGR can be mediated by impaired placentation. Insulin-like growth factors (IGF) regulate placentation due to stimulatory effects on extravillous trophoblasts, which are highly motile and invasive. Previous studies demonstrated that extravillous trophoblasts express high levels of aspartyl-(asparaginyl) beta-hydroxylase (AAH), a gene that is regulated by IGF and has a critical role in cell motility and invasion. The present study examines the hypothesis that ethanol impaired placentation is associated with inhibition of AAH expression in trophoblasts. Pregnant Long Evans rats were fed isocaloric liquid diets containing 0% or 37% ethanol by caloric content. Placentas harvested on gestation day 16 were used for histopathological, mRNA, and protein studies to examine AAH expression in relation to the integrity of placentation and ethanol exposure. Chronic ethanol feeding prevented or impaired the physiological conversion of uterine vessels required for expansion of maternal circulation into placenta, a crucial process for adequate placentation. Real-time quantitative RT-PCR analysis demonstrated significant reductions in IRS-1, IRS-2, and significant increases in IGF-II and IGF-II receptor mRNA levels in ethanol-exposed placentas. These abnormalities were associated with significantly reduced levels of AAH expression in trophoblastic cells, particularly within the mesometrial triangle (deep placental bed) as demonstrated by real time quantitative RT-PCR, Western blot analysis, ELISA, and immunohistochemical staining. Ethanol-impaired placentation is associated with inhibition of AAH expression in trophoblasts. This effect of chronic gestational exposure to ethanol may contribute to IUGR in FAS.
The investigation established and validated methods to measure multiple biochemical indices of condition (whole body total lipids, whole body triglycerides, muscle RNA : DNA ratio and muscle protein) simultaneously in the same individual juvenile fish. It also provided examples of their application using a species comparison (salmonids and cyprinids) of the degree of change in these indices after food deprivation. The results showed that juvenile rainbow trout Oncorhynchus mykiss were much more susceptible to a decline in all biochemical indices of condition than juvenile fathead minnows Pimephales promelas upon food deprivation. The combination of these techniques can be used to accurately assess condition and growth potential of individuals from wild fish populations.
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