A great deal of evidence has confirmed that electromagnetic fields (EMFs) can affect the central nervous system. In this study, cultured neonatal human retinal pigment epithelial (hRPE) cells were exposed to pulsed EMF of 1 mT intensity and 50 Hz frequency 8 h daily for 3 days. In addition to cell proliferation and cell death assays, immunocytochemistry for RPE65, PAX6, nestin, and cytokeratin 8/18 proteins were performed. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) was performed for NES, PAX6, RPE65, and ACTA2 gene expression. Exposed hRPE cells did not demonstrate significant change in terms of cytomorphology, cell proliferation, or cell death. Protein expression of PAX6 was decreased in treated cells compared to controls and remained unchanged for RPE65, cytokeratin 8/18, and nestin. Gene expressions of NES, RPE65, and PAX6 were decreased in treated cells as compared to controls. Gene expression of ACTA2 did not significantly change. In conclusion, viability of cultivated neonatal hRPE cells did not change after short exposure to a safe dose of pulsed EMF albeit that both gene and protein expressions of retinal progenitor cell markers were reduced. Whether longer exposure durations that are being constantly produced by widely-used electronic devices may induce significant changes in these cells, needs further investigation. Bioelectromagnetics. 39:585-594, 2018.
New Zealand deer farming centres on the production of meat and velvet antler. Velvet antler removal is a painful procedure and currently, New Zealand Animal Welfare regulations dictate surgical removal of velvet antlers under lignocaine anaesthesia. To improve our knowledge on the efficacy and duration of other local anaesthetics to mitigate pain after antler removal, it is important to accurately assess and quantify pain arising from antler removal. Therefore, the current study was designed to validate mechanical nociceptive threshold (MNT) testing using a Wagner hand-held algometer, and to apply this methodology to assess the efficacy and duration of action of articaine for antler removal in deer. Baseline force (N) required to elicit the nociceptive response was recorded in 40 yearling male red deer on three alternate days. Ten of the 40 animals were selected for antler removal after administration of 4% articaine hydrochloride as a ring block. The duration of analgesic efficacy of articaine was assessed by algometry across 5 time points. There was a significant difference in MNTs among the three days (day 3 versus day 1 (p < 0.0001), day 2 versus day 1 (p < 0.0001), and day 1 versus day 2 (p < 0.01)). Positive correlations were observed between weight, antler length and thresholds. The MNT values remained above 20N for 6 h after removal of velvet antlers under the articaine ring block. This study provides valuable information about the use of MNT in red deer. These findings lay a foundation for future studies in the topics of peri-operative and postoperative pain management in deer antler removal, and a possible alternative use for articaine.
Background : To compare the duration of action of a local anesthetic block using a lipid formulation of bupivacaine to the commercially available aqueous formulation. Bupivacaine 0.5% was mixed with an equal volume of either lipid emulsion (Intralipid, Fresenius Kabi) or normal saline resulting in a final concentration of 0.25% bupivacaine. Eighteen sheep were administered a n erve block of either control or treatment at the metacarpal region of each forelimb to compare the efficacy of the injected formulations. The nociceptive test was determined by applying a blunt noxious stimulus to the foot below the nerve block at multiple time intervals until the sheep responded by withdrawing its foot. The person assessing the response to the noxious stimulus was blinded to the treatment. Results: The Intralipid formulation significantly extended the duration of the nerve block compared to the control group. The mean analgesic period (mean±SD) in the control legs was 4.23±1.8 hr. compared to 5.81±1.78 hr. in the Intralipid injected legs (p=0.013). Conclusions : In conclusion, an Intralipid® - based formulation provided a more prolonged dura tion of local anesthesia after nerve blocks in the sheep metacarpal region compared to aqueous bupivacaine.
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