Biochemical and behavioral effects of decreasing dietary linoleic acid and increasing eicosapentaenoic acid and docosahexaenoic acid in a rat chronic monoarthrits model

Clinical studies have demonstrated that decreasing linoleic acid (LA) while increasing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in diets evokes an analgesic effect in headache sufferers. We utilized a rat chronic monoarthritis model to determine if these analgesic effects can be reproduced in rats and to and further probe potential analgesic mechanisms. We fed 8 rats a control diet (with fatty acid levels similar to standard US diets) and 8 rats a low LA diet with added EPA and DHA (H3L6 diet) and after 10 weeks, performed a unilateral intraarticular injection of Complete's Freund Adjuvant (CFA). We evaluated thermal and mechanical sensitivity as well as hind paw weight bearing prior to and at 4 and 20 days post CFA injection. At 28 days post CFA injection rats were euthanized and tissue collected. H3L6 diet fed rats had higher concentrations of EPA and DHA, as well as higher concentrations of oxidized lipids derived from these fatty acids, in hind paw and plasma, compared to control fed rats. LA and oxidized LA metabolites were lower in the plasma and hind paw of H3L6 compared to control fed rats. Diet did not affect thermal or mechanical sensitivity, nor did it affect hind paw weight bearing. In conclusion, the H3L6 diet evoked biochemical changes in rats but did not impact pain related behavioral measures in this chronic monoarthritis model.

A dose response study of the effect of prostaglandin E2 on thermal nociceptive sensitivity

Inhibition of prostaglandin (PG) biosynthesis has been used to relieve pain for thousands of years. Today non-steroidal anti-inflammatory drugs (which largely inhibit PG synthesis) are widely used to treat pain. Four main types of PGs (PGD2, PGE2, PGF2 and PGI2) are synthesized from arachidonic acid during inflammation and have been demonstrated to impact nociception. PGE2 has been the most studied and utilized for its pain producing properties and has been demonstrated to increase hypersensitivity in rodent nociceptive behavioral models when applied centrally and/or peripherally. Surprisingly, there are no published reports that use withdrawal from radiant light beam (Hargreaves apparatus) to examine the dose response effect of peripherally applied PGE2 on thermal nociceptive hypersensitivity. To address this gap in the literature, we performed a dose response study examining the effect of PGE2 on thermal hypersensitivity (assessed using a Hargreaves apparatus) where rats were injected with 0.003-30μg of PGE2, intradermally into the hindpaw. Thermal hypersensitivity was assessed by measuring withdraw latency from a radiant light beam (Hargreaves test) and our primary objective was to determine the dose of PGE2 causing the most pronounced increase in thermal hypersensitivity (i.e. lowest withdraw latency). A secondary objective was to determine the minimum dose of PGE2 required to cause statistically significant decreases in thermal withdrawal latency as compared to rats injected with vehicle. We found that rats injected with the 30μg dose of PGE2 exhibited the most pronounced thermal nociceptive hypersensitivity though secondary analysis showed that rats injected with PGE2 doses of 0.03-30μg had lower withdrawal latencies as compared to rats injected with vehicle. This work fills an evidence gap and provides context to guide dose selection in future rodent pain behavior studies.

Friendly visiting as a means of informing homebound senior citizens of health-related community services

Health-related community services designed for the senior population include delivered and congregate meals, visiting health-aides and nurses, adult day care and telephone and postal checks. Friendly visiting programs may prove helpful in informing homebound senior citizens of these health-related community services. The purpose of this study was to investigate the effectiveness of friendly visiting as a means of informing homebound senior citizens of health-related community services. Visited homebound seniors were contrasted with homebound controls. Visiting occurred in two forms. One group received visitors from an ongoing friendly visiting program (VISITING AS IS) in their community and a second group received visitors who were specifically trained to convey community referral information (REACH). A control group received no visiting of any kind. All three groups were administered pre- and post-interviews asking their knowledge of eight community services. At the end of the twelve week program, the post-interview means of the two homebound visited groups did differ significantly from the mean of the unvisited controls when contrasts were made using pre-interview scores as the covariate, F(2,78) = 8.19 (p less than .05). The homebound senior citizens visited by the REACH visitors increased their knowledge of services significantly more than the homebound seniors contacted by VISITING AS IS visitors F(1,52) = 7.20 (p less than .01). While the simple act of being visited did lead to increased knowledge at the .05 level, trained visitors were able to convey such information to a greater degree (p less than .01). Awareness of community services can be effectively transmitted by friendly visitors and improved when a program is implemented to train the visitors to meet his goal.