Publications by authors named "Irne du Plessis"

Objective: To determine whether deep brain stimulation (DBS) causes swimming impairment, we systematically compared swimming ability between DBS on vs off in 18 patients.

Methods: We conducted a randomized blinded crossover study, comparing swimming ability between DBS on vs off, within participants. Participants swam 3 laps of front crawl and 3 laps of breaststroke.

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Although peripherally released interleukin (IL)-6 is critical for fever, its role in sickness behaviors, in particular anorexia and lethargy, induced by lipopolysaccharide (LPS) administration appears to be less important. Using quantifiable measures of fever, anorexia and lethargy, that is, body temperature, food intake and voluntary wheel-running, we investigated whether the less-than-essential role for IL-6 in mediating sickness behaviors compared to fever implies important roles for other inflammatory mediators, particularly IL-1β and prostanoids, in these responses. Male Sprague-Dawley rats were randomly assigned to receive one of the following three injections before receiving a subcutaneous (SC) injection of LPS (250 μg/kg) or saline: (1) intraperitoneal injection of pre-immune serum or antiserum to IL-6 (IL-6AS), to reduce the biological activity of peripherally released IL-6; (2) intracerebroventricular injection of vehicle or a caspase-1 inhibitor, to inhibit the production of mature IL-1β; or (3) intraperitoneal injection of vehicle or one of the two doses (1 or 10 mg/kg) of diclofenac, a nonselective cyclooxygenase inhibitor shown to block the formation of prostanoids.

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Pro-inflammatory cytokines interleukin (IL)-6 and IL-1 beta can act in the brain (centrally) to cause fever. Sickness behaviors which accompany fever also appear to involve the central action of IL-1 beta. We injected species-homologous rat IL-6 and IL-1 beta directly into the brains of conscious rats to examine the effect of these cytokines on fever, and two behaviors affected by sickness, voluntary wheel-running and food intake.

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We determined c-Fos immunoreactivity (Fos-IR) in selected hypothalamic nuclei, the organum vasculosum of the laminae terminals (OVLT) and somatosensory cortex of rats after hyperthermia induced by exogenous heat exposure, Gram-negative or Gram-positive pyrogen administration. The magnitude of Fos-IR was similar in thermoregulatory hypothalamic nuclei of rats after heat exposure or lipopolysaccharide (LPS) injection, despite the different origins of the hyperthermias. Heat-induced hyperthermia was associated with increased Fos-IR in the somatosensory cortex.

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Pro-inflammatory cytokines, interleukin (IL)-1beta, IL-6 and tumor necrosis factor-alpha (TNF-alpha) synthesized by activated macrophages and monocytes in response to administration of lipopolysaccharide (LPS), are considered important mediators of fever and sickness behavior. We administered rat-specific antisera for TNF-alpha, IL-1beta, IL-6 and leptin, to determine the involvement of peripherally released cytokines in LPS-induced fever and sickness behavior, measured as suppression of voluntary wheel-running and food intake. Male Sprague-Dawley rats (approximately 200 g) selected for their predisposition to spontaneously run on running wheels were anaesthetized with a combination of ketamine hydrochloride (80 mg/kg i.

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We aimed to establish whether exposing the tails of rats to ultraviolet A (UVA) light generated sustained hyperalgesia to noxious thermal and mechanical challenges. The tails of 21 rats underwent eight 40s exposures of UVA light, with 260s between each exposure. As a control procedure, during UVA-light exposure the tails of 11 of those rats were shielded with aluminium foil.

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