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Anita Smith

Publications and source records attributed to Anita Smith.

4 recordsLinked to original sources

Downregulation of renal CYP-derived eicosanoid synthesis in rats with diet-induced hypertension.

The incidence of essential hypertension increases with obesity; however, the mechanisms that link obesity with hypertension are unclear. Renal cytochrome P450 (CYP)-derived eicosanoids--hydroxyeicosatetraenoic acids (HETEs), epoxyeicosatrienoic acids (EETs), and dihydroxyeicosatrienoic acids (DHETs)--have been shown to play an important role in the regulation of renal function, vascular tone, and blood pressure. The objective of this study was to examine CYP-derived eicosanoid synthesis in the different renal zones (cortex, medulla, and papilla) of rats fed a high fat diet (HF). Male Sprague-Dawley rats were fed a HF diet or regular rat chow for 10 weeks. After 10 weeks, HF rats showed significantly higher systolic blood pressure, body weight, and fat:body weight ratio. The renal omega-hydroxylase activity was decreased by 46% in cortex, 43% in medulla, and 46% in papilla of HF rats. The renal epoxygenase activity was decreased by 46% in cortex, 31% in medulla, and 56% in papilla of HF rats. Interestingly, the changes in the rate of 20-HETE and EET formation in different renal zones were consistent with the levels of expression of CYP4A and CYP2C23 proteins, respectively. Furthermore, there were no significant changes in the synthesis of these metabolites in the renal microvessels. These results demonstrate that HF diet causes the downregulation of CYP4A and CYP2C23 in renal tubules, and these proteins are responsible for renal 20-HETE and EET formation. The reduction in the synthesis of these eicosanoids may play an important role in the regulation of renal function and blood pressure in obesity-induced hypertension.

Animals↗

The effects of outward forced convective flow on inward diffusion of potassium across human dentin.

PURPOSE: To measure the inward flux of potassium across human dentin disks, in vitro, in the absence and then in the presence of a simulated pulpal pressure (PP), before and after brushing with two desensitizing dentifrices. MATERIALS AND METHODS: Dentin discs were made from extracted unerupted third molars and etched with 6% citric acid to remove the smear layers. The hydraulic conductance (Lp or outward fluid movement) of the discs was measured before and after brushing for 2 minutes with two desensitizing dentifrices, Colgate Sensitive Maximum Strength or Sensodyne Fresh Mint, both dentifrices containing 5% potassium nitrate. The potassium flux was measured at a pressure of 0 cm H2O, and a simulated pulpal pressure of 20 cm H2O. RESULTS: The results showed the Colgate-brushed specimens had lower Lp (P < 0.05) than specimens brushed with Sensodyne or with saline. The Colgate-brushed specimens had a corresponding lower K+ flux, at a PP = 0 cm H2O, than specimens brushed with saline, but were not significantly different than specimens brushed with Sensodyne dentifrice. However, when the pressure was increased from 0 to 20 cm H2O, to simulate outward dentin fluid pressure, there were significant decreases in K+ flux across all three treatment groups, but the K+ flux of the Colgate-brushed specimens were affected the least, resulting in the Colgate-brushed specimens having significantly (P < 0.05) greater K+ fluxes than the saline or Sensodyne dentifrice-brushed groups. The magnitude of reduction in K+ flux in going from 0 cm H2O to 20 cm H2O was demonstrated to be linearly related to the magnitude of the Lp of the brushed specimens. Hence, a small Lp corresponded to a small reduction in K+ flux, and a correspondingly large K+ flux at 20 cm H2O. An explanation of this phenomenon is that a decrease in the Lp of dentin, produced by brushing, corresponds to a decreased outward dentin fluid flow. This lowers the outward K+ convective flow and also lowers the inward K+ diffusion. However, since the decrease of the outward K+ convective flow is greater than the decrease of the inward K+ diffusion, and the net flux is the algebraic sum of these two terms, the result is greater net inward K+ flux through the dentin. Therefore, the Colgate-brushed specimens, which exhibited the lowest Lp, provided the greatest inward K+ flux at simulated dentin fluid pressure.

Analysis of Variance↗

Preceptor continuity in a nurse internship program: the nurse intern's perception.

The purpose of this study was to examine the new graduate's perception of preceptor continuity in regard to clinical performance, role transition, satisfaction, and retention in nursing. Determining how the new graduate perceives the role of a preceptor or multiple preceptors in a new graduate program is instrumental in evaluating and adapting the program to meet the needs of the new nurse graduate.

Adult↗