Yu-Chun Hung

L-type calcium channels are involved in mediating the anti-inflammatory effects of magnesium sulphate

BACKGROUND Magnesium sulphate (MgSO(4)) has potent anti-inflammatory capacity. It is a natural calcium antagonist and a potent L-type calcium channel inhibitor. We sought to elucidate the possible role of calcium, the L-type calcium channels, or both in mediating the anti-inflammatory effects of MgSO(4). METHODS RAW264.7 cells, an immortalized murine macrophage-like cell line, were treated with phosphate buffered saline, MgSO(4), lipopolysaccharide (LPS), LPS plus MgSO(4), LPS plus MgSO(4) plus extra-cellular supplement with calcium chloride (CaCl(2)), or LPS plus MgSO(4) plus the L-type calcium channel activator BAY-K8644. After harvesting, the production of inflammatory molecules was evaluated. Because the production of endotoxin-induced inflammatory molecules is regulated by the crucial transcription factor nuclear factor (NF)-kappaB, we also evaluated the expression of NF-kappaB. RESULTS LPS significantly induced the production of inflammatory molecules, including macrophage inflammatory protein-2, tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-6, nitric oxide/inducible nitric oxide synthase, and prostaglandin E(2)/cyclo-oxygenase-2. LPS also induced NF-kappaB activation, as inhibitor-kappaB degradation, NF-kappaB nuclear translocation, and NF-kappaB-DNA binding activity were significantly increased in LPS-treated RAW264.7 cells. MgSO(4), in contrast, significantly inhibited the LPS-induced inflammatory molecules production and NF-kappaB activation. Moreover, the effects of MgSO(4) on inflammatory molecules and NF-kappaB were reversed by extra-cellular calcium supplement with CaCl(2) and L-type calcium channel activator BAY-K8644. CONCLUSIONS MgSO(4) significantly inhibited endotoxin-induced up-regulation of inflammatory molecules and NF-kappaB activation in activated RAW264.7 cells. The effects of MgSO(4) on inflammatory molecules and NF-kappaB may involve antagonizing calcium, inhibiting the L-type calcium channels, or both.

Premedication with mirtazapine reduces preoperative anxiety and postoperative nausea and vomiting.

BACKGROUND:Mirtazapine is a new antidepressant that blocks 5-HT2 and 5-HT3 receptors. With this receptor profile, it is possible that mirtazapine could provide both anxiolysis and efficacy for postoperative nausea and vomiting (PONV). We therefore tested the hypothesis that premedication with mirtazapine can reduce preoperative anxiety and PONV. METHODS:Eighty female patients with at least two PONV risk factors scheduled for gynecological surgery were enrolled. Dexamethasone 8 mg was given before induction of anesthesia and patients were randomly assigned to group M + D (mirtazapine plus dexamethasone) or group dexamethasone. An oral disintegrating mirtazapine 30 mg or placebo tablet was given 1 h before surgery. Preoperative anxiety level was assessed by a visual analog scale (VAS) before mirtazapine administration and 1 h thereafter. General anesthesia was induced with 1% propofol at the rate of 200 mL/h (until loss of consciousness) and was then maintained with sevoflurane in oxygen and air. An auditory evoked potentials index monitor was used to titrate sevoflurane. The incidence of PONV, the use of rescue antiemetic, complete response, postoperative Ramsay Sedation Scores, and VAS pain scores were assessed 1, 2, and 24 h after surgery and compared. RESULTS:The VAS anxiety scale was lower in group M + D after mirtazapine administration. There were no differences in the induction dose of propofol, the concentrations of sevoflurane during anesthesia, and recovery times between the two groups. The incidence of complete response to PONV over 0–24 h was lower in group M + D (80% vs 50%, P < 0.01). CONCLUSIONS:Premedication with mirtazapine 30 mg reduces the level of preoperative anxiety and the risk of PONV in moderate and high-risk female patients.

Chronic intrathecal infusion of gabapentin prevents nerve ligation-induced pain in rats

BACKGROUND Gabapentin is an anticonvulsant and adjuvant analgesic. It is effective in several pain studies. Neuropathic pain is the most difficult type of pain to treat. In this study, we examined if intrathecal gabapentin could prevent nerve injury-induced pain. METHODS Under isoflurane anaesthesia, male Sprague-Dawley rats (200-250 g) underwent right L5/6 spinal nerve ligation and placement of an intrathecal catheter connected to an infusion pump. After surgery, intrathecal saline or gabapentin (20 µg h(-1)) was given for 7 days (n=8 per group). The right hind paw withdrawal threshold to von Frey filament stimuli and withdrawal latency to radiant heat were determined before (baseline) and once daily for 7 days after surgery. Haematoxylin and eosin and toluidine blue staining were used to evaluate the neurotoxicity of gabapentin (40 µg h(-1)). RESULTS Seven days after nerve ligation, the affected paw withdrawal threshold and latency of saline-treated rats decreased from the baseline 11.7 (11.7-22.2) [median (inter-quartile range)] to 1.6 (0.9-3.2) g and 10.8 (10.5-11.2) to 4.3 (4.2-7) s, respectively. Rats receiving gabapentin (20 µg h(-1)) had higher withdrawal threshold [9.9 (9.9-19.3) g] and latency [11.5 (9.7-11.9) s] on day 7 after ligation. No obvious histopathological change or growth retardation was detected after intrathecal gabapentin (40 µg h(-1)) infusion. CONCLUSIONS We showed a preventative effect of intrathecal gabapentin on the development of nerve injury-induced mechanical allodynia and thermal hyperalgesia. Our data suggest that continuous intrathecal gabapentin may be considered as an alternative for the prevention of nerve injury-induced pain.

Ultrasound-Guided Pulsed Radiofrequency of Suprascapular Nerve for Chronic Shoulder Pain: A Case Report

Suprascapular nerve (SSN) blockade improves pain, range of motion, and disability in acute and chronic shoulder pain. Pain relief usually lasts several hours with local anesthetic. If steroids are added, the relief lasts several weeks. Since repetitive steroid exposure is associated with several hazards, alternative long-term therapies would be desirable. Pulsed radiofrequency (PRF) is a non-destructive, safe, and repeatable long-term pain control therapy. We report a case, wherein using ultrasound guidance and fluoroscopy and nerve stimulation confirmation, SSN PRF treatment was performed. It provided 9-10 months of pain relief and improvement in shoulder function, without deterioration in muscle strength.

Ultrasound-Guided Intercostal Nerve Block for Intractable Right Upper Quadrant Abdominal Pain: A Case Report

Abdominal visceral organ pathology is commonly the source of abdominal pain. However, some abdominal pain may originate from the abdominal wall muscles and be somatic in origin. Transversus Abdominis Plane (TAP) block is an effective block to offer analgesia for abdominal somatic pain. Intercostal nerve (ICN) blockade is also an useful diagnostic and therapeutic tool to manage pain covered by the distribution of thoracic nerves. Chronic abdominal wall pain can often be missed as a differential diagnosis for patients suffering with abdominal pain. We present a case of intractable right upper quadrant (RUQ) abdominal pain managed successfully with ultrasound-guided TAP and ICN block.