[Value of multidetector CT on aiding intraoperative judgement of serosal invasion of gastric cancer]

OBJECTIVE

To explore the value of multidetector CT on aiding intraoperative judgement of serosal invasion of gastric cancer.

METHODS

Clinical data of 206 cases of gastric cancer undergoing radical surgery in the First Hosptial of China Medical University from August 2009 to June 2011 were analyzed retrospectively. Preoperative CT findings and intraoperative judgement of serosal invasion in gastric cancer were compared with pathological results in order to investigate their values.

RESULTS

The sensitivity and specificity of preoperative CT findings and intraoperative judgement of serosal invasion were 88.5%, 81.5% and 98.9%, 61.3%, respectively. The accuracy of preoperative CT in diagnosing serosal invasion was higher than that of intraoperative judgement, while the difference was not statistically significant (84.5% vs. 77.2%, P=0.060). The rates of serosal invasion of normal type, reactive type, nodular type, tendonoid type and color-diffused type were 0 (0/29), 2.5% (1/40), 40.5% (15/37), 59.2% (29/49), and 82.4% (42/51) respectively. The accuracy of preoperative CT in diagnosing serosal invasion of gastric cancer with tendonoid type was higher than that of intraoperative judgement, and the difference was statistically significant (61.2% vs. 87.8%, P=0.002).

CONCLUSIONS

Multidetector CT plays an important role in aiding intraoperation judgement of serosal invasion of gastric cancer. For gastric cancer with tendonoid and color-diffused macroscopic serosal appearance, surgeons should pay attention to the value of preoperative CT findings.

Chemokine signaling involving chemokine (C-C motif) ligand 2 plays a role in descending pain facilitation

OBJECTIVE

Despite accumulating evidence on a role of immune cells and their associated chemicals in mechanisms of pain, few studies have addressed the potential role of chemokines in the descending facilitation of persistent pain. The present study was undertaken to test the hypothesis that the chemokine (C-C motif) ligand 2 (CCL2) (commonly known as monocyte chemoattractant protein-1) signaling in the rostral ventromedial medulla (RVM), a pivotal structure in brainstem pain modulatory circuitry, is involved in descending pain facilitation in rats.

METHODS

An L5 spinal nerve ligation (SNL) was produced in rats under pentobarbital anesthesia. Western blot and immunohistochemistry were used to detect the expression levels of CCL2 and CCL2 receptor (CCR2), and examine their distributions compared with the neuronal marker NeuN as well as glial markers glial fibrillary acidic protein (GFAP, astroglial) and CD11b (microglial), respectively.

RESULTS

SNL induced an increase in CCL2 expression in the RVM, and this returned to the control level at 4 weeks after injury. The induced CCL2 colocalized with NeuN, but not with GFAP and CD11b. CCR2 was also upregulated by SNL in the RVM, and this increase lasted for at least 4 weeks. CCR2 was colocalized with CD11b but not GFAP. Few RVM neurons also exhibited CCR2 staining. Neutralizing CCL2 with an anti-CCL2 antibody (0.2-20 ng) or injecting RS-102895 (0.1-10 pmol), a CCR2b chemokine receptor antagonist, into the RVM on day 1 after SNL, significantly attenuated the established thermal and mechanical hypersensitivity. In addition, injection of recombinant rat CCL2 (0.03-3 pmol) into the RVM induced dose-dependent hyperalgesia, which was prevented by pretreatment with RS-102895 (10 pmol). Interleukin-1β (IL-1β), a potent inducer of neuronal CCL2, was also selectively upregulated in RVM reactive astrocytes. Injection of IL-1β (120 fmol) into the RVM induced behavioral hyperalgesia, which was blocked by RS-102895 (10 pmol). However, an IL-1 receptor antagonist (3 pmol) did not prevent CCL2 (3 pmol)-induced hyperalgesia. These results suggest that the effect of CCL2 is downstream to IL-1β signaling.

CONCLUSION

The IL-1β and CCL2-CCR2 signaling cascades play a role in neuron-glia-cytokine interactions and the descending facilitation of neuropathic pain.

Electroacupuncture alleviates affective pain in an inflammatory pain rat model

Pain has both sensory-discriminative and emotional-affective dimensions. Previous studies demonstrate that electroacupuncture (EA) alleviates the sensory dimension but do not address the affective. An inflammatory pain rat model, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a conditioned place avoidance (CPA) test to determine whether EA inhibits spontaneous pain-induced affective response and, if so, to study the possibility that rostral anterior cingulate cortex (rACC) opioids underlie this effect. Male Sprague-Dawley rats (250-275 g, Harlan) were used. The rats showed place aversion (i.e. affective pain) by spending less time in a pain-paired compartment after conditioning than during a preconditioning test. Systemic non-analgesic morphine (0.5 and 1.0 mg/kg, i.p.) inhibited the affective reaction, suggesting that the affective dimension is underpinned by mechanisms different from those of the sensory dimension of pain. Morphine at 0.5 and at 1 mg/kg did not induce reward. Rats given EA treatment before pain-paired conditioning at GB 30 showed no aversion to the pain-paired compartment, indicating that EA inhibited the affective dimension. EA treatment did not produce reward or aversive effect. Intra-rACC administration of D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide (CTOP), a selective mu opioid receptor antagonist, but not norbinaltorphimine (nor-BNI), a selective kappa opioid receptor antagonist, blocked EA inhibition of the affective dimension. These data demonstrate that EA activates opioid receptors in the rACC to inhibit pain-induced affective responses and that EA may be an effective therapy for both the sensory-discriminative and the affective dimensions of pain.

[Study on the correlation between membrane protein Flotillin-1 and PrPc endocytosis]

OBJECTIVE

To explore whether the membrane-associated protein Flotillin-1 has relationship with endocytosis of PrPc.

METHODS

The expression of Flotillin-1 in different cell lines was detected with the method of Western Blot; the interaction between Flotillin-1 and PrPc in Cells which were treated with copper ions was observed using immunoprecipitation method.

RESULTS

(1) Flotillin-1 was widely expressed in many cell lines without significant difference in the amounts of expression level; (2) Only in the appearance of copper ions, the protein complexes of PrPc and Flotillin-1 can be detected with the method of IP, which were related to copper ions concentration and processing time.

CONCLUSION

The membrane-associated protein Flotillin-1 has the relationship with the endocytosis of PrPc.

Trigeminal-rostral ventromedial medulla circuitry is involved in orofacial hyperalgesia contralateral to tissue injury

BACKGROUND

Our previous studies have shown that complete Freund's adjuvant (CFA)-induced masseter inflammation and microinjection of the pro-inflammatory cytokine interleukin-1β (IL-1β) into the subnucleus interpolaris/subnucleus caudalis transition zone of the spinal trigeminal nucleus (Vi/Vc) can induce contralateral orofacial hyperalgesia in rat models. We have also shown that contralateral hyperalgesia is attenuated with a lesion of the rostral ventromedial medulla (RVM), a critical site of descending pain modulation. Here we investigated the involvement of the RVM-Vi/Vc circuitry in mediating contralateral orofacial hyperalgesia after an injection of CFA into the masseter muscle.

RESULTS

Microinjection of the IL-1 receptor antagonist (5 nmol, n=6) into the ipsilateral Vi/Vc attenuated the CFA-induced contralateral hyperalgesia but not the ipsilateral hyperalgesia. Intra-RVM post-treatment injection of the NK1 receptor antagonists, RP67580 (0.5-11.4 nmol) and L-733,060 (0.5-11.4 nmol), attenuated CFA-induced bilateral hyperalgesia and IL-1β induced bilateral hyperalgesia. Serotonin depletion in RVM neurons prior to intra-masseter CFA injection prevented the development of contralateral hyperalgesia 1-3 days after CFA injection. Inhibition of 5-HT(3) receptors in the contralateral Vi/Vc with direct microinjection of the select 5-HT(3) receptor antagonist, Y-25130 (2.6-12.9 nmol), attenuated CFA-induced contralateral hyperalgesia. Lesions to the ipsilateral Vc prevented the development of ipsilateral hyperalgesia but did not prevent the development of contralateral hyperalgesia.

CONCLUSIONS

These results suggest that the development of CFA-induced contralateral orofacial hyperalgesia is mediated through descending facilitatory mechanisms of the RVM-Vi/Vc circuitry.

[Mutant D178N prion protein converts spontaneously in RT-QuIC assay]

OBJECTIVE

To study the conversion of mutant D178N prion protein in RT-QuIC assay.

METHODS

The D178N mutant prion PRNP was generated by the method of single site mutation. The mutant PRNP gene was inserted into plasmids of pET24. The full and N-truncated recombinant human prion proteins were expressed and purified. The fibril formations of these proteins were real-time monitored by the method of RT-QuIC. The ability to resist proteinase K (PK) of these fibrils was analyzed.

RESULTS

We succeed to construct human PrP-D178N plamids. The N-truncated human prion protein with D178N (PrP90-231-D178N) can convert spontaneously in RT-QuIC, while full length of human prion D178N protein (PrP23-231-D178N) fails to convert spontaneously. The spontaneously generated fibril has been domenstrated it is partily PK-resistant.

CONCLUSION

The N-terminal of prion protein (23-90) plays an important role for the D178N mutant protein spontaneously conversion, which provide the clues for study the pathogenesis of genetic CJD.

Primary clavicle tumors and tumorous lesions: a review of 206 cases in East Asia

PURPOSE

The aim of this study is to systematically review the published literature from East Asia on the clinical, pathological, and epidemiological characteristics of primary clavicle tumor and tumorous lesions.

METHODS

A computerized search based on keywords "clavicle," "tumor," and "tumorous lesion" (both in Chinese and in English) was performed on literature published from 1980 to 2011 in East Asian countries, including China, Japan, South Korea, North Korea, and Mongolia. An analysis was carried out with unified inclusion and exclusion criteria.

RESULTS

Two hundred and six cases were identified. The age of onset ranged from 1.5 to 70, with an average age of 29.4, and a male/female ratio of 1.53:1. Lesion locations included 28.9% in medial third, 18.8% in the middle third, and 33.6% in the lateral third of the clavicle. Another 7.4% involved both the medial and middle thirds, 7.4% involved both the middle and lateral thirds, and 4.0% involved the entire length of the clavicle. Major pathological types included 18.5% eosinophilic granuloma, 10.2% plasmocytoma, 7.8% Ewing sarcoma, 8.7% osteosarcoma, 8.7% osteochondroma, and 5.3% chondrosarcoma. The age of onset was found to be strongly correlated with the benign/ malignant ratio. Clavicle malignancy was rarely found in patients younger than 10 years, while the incidence of malignancy greatly increased among patients over 40 years old. Total or subtotal claviculectomy was the most common treatment in cases for which treatment information was available. Of these, 40.8% of patients received reconstruction with allograft or autograft.

CONCLUSIONS

Clavicle tumors and tumorous lesions in East Asia had an inclined occurrence in respect to age and gender. The most common tumors were eosinophilic granuloma and tumors derived from the bone marrow hematopoietic system. Age of onset was found to be a risk factor for malignancy. These characteristics may be related to the special tissue structures and mode of development in the clavicle as well as to the genetic traits of the typical Mongoloids in East Asia.

Electroacupuncture inhibition of hyperalgesia in an inflammatory pain rat model: involvement of distinct spinal serotonin and norepinephrine receptor subtypes

BACKGROUND

Although acupuncture analgesia is well documented, its mechanisms have not been thoroughly clarified. We previously showed that electroacupuncture (EA) activates supraspinal serotonin- and norepinephrine-containing neurones that project to the spinal cord. This study investigates the involvement of spinal alpha(2)-adrenoceptors (α2-ARs) and 5-hydroxytryptamine (serotonin) receptors (5-HTRs) in EA effects on an inflammatory pain rat model.

METHODS

Inflammatory hyperalgesia was induced by injecting complete Freund's adjuvant (CFA, 0.08 ml) into the plantar surface of one hind paw and assessed by paw withdrawal latency (PWL) to a noxious thermal stimulus. The selective α2a-AR antagonist BRL-44408, α2b-AR antagonist imiloxan hydrochloride, 5-HT2B receptor (5-HT2BR) antagonist SB204741, 5-HT3R antagonist LY278584, or 5-HT1AR antagonists NAN-190 hydrobromide, or WAY-100635 were intrathecally administered 20 min before EA or sham EA, which was given 2 h post-CFA at acupoint GB30.

RESULTS

EA significantly increased PWL compared with sham [7.20 (0.46) vs 5.20 (0.43) s]. Pretreatment with α2a-AR [5.35 (0.45) s] or 5-HT1AR [5.22 (0.38) s] antagonists blocked EA-produced anti-hyperalgesia; α2b-AR, 5-HT2BR, and 5-HT3R antagonist pretreatment did not. Sham plus these antagonists did not significantly change PWL compared with sham plus vehicle, indicating that the antagonists had little effect on PWL. Immunohistochemical staining demonstrated that α2a-ARs are on primary afferents and 5-HT1ARs are localized in N-methyl-d-aspartic acid (NMDA) subunit NR1-containing neurones in the spinal dorsal horn.

CONCLUSIONS

The data show that α2a-ARs and 5-HT1ARs are involved in the EA inhibition of inflammatory pain and that the NMDA receptors are involved in EA action.

Cannabinoids suppress inflammatory and neuropathic pain by targeting α3 glycine receptors

Systemic and intrathecal administration of derivatives of a nonpsychoactive component of marijuana significantly suppresses chronic inflammatory and neuropathic pain, without causing analgesic tolerance, in several rodent models.

Certain types of nonpsychoactive cannabinoids can potentiate glycine receptors (GlyRs), an important target for nociceptive regulation at the spinal level. However, little is known about the potential and mechanism of glycinergic cannabinoids for chronic pain treatment. We report that systemic and intrathecal administration of cannabidiol (CBD), a major nonpsychoactive component of marijuana, and its modified derivatives significantly suppress chronic inflammatory and neuropathic pain without causing apparent analgesic tolerance in rodents. The cannabinoids significantly potentiate glycine currents in dorsal horn neurons in rat spinal cord slices. The analgesic potency of 11 structurally similar cannabinoids is positively correlated with cannabinoid potentiation of the α3 GlyRs. In contrast, the cannabinoid analgesia is neither correlated with their binding affinity for CB1 and CB2 receptors nor with their psychoactive side effects. NMR analysis reveals a direct interaction between CBD and S296 in the third transmembrane domain of purified α3 GlyR. The cannabinoid-induced analgesic effect is absent in mice lacking the α3 GlyRs. Our findings suggest that the α3 GlyRs mediate glycinergic cannabinoid-induced suppression of chronic pain. These cannabinoids may represent a novel class of therapeutic agents for the treatment of chronic pain and other diseases involving GlyR dysfunction.

[A clinical study of pituitrin versus norepinephrine in the treatment of patients with septic shock]

OBJECTIVE

To investigate whether pituitrin can lower 28-day mortality as compared with treatment with norepinephrine (NE) in patients with septic shock.

METHODS

Randomized, controlled, open-label trial was conducted. One hundred and thirty-nine septic shock patients with dopamine requirements exceeding 5 μg×kg(-1)×min(-1) were divided at random into two groups as the study group and control group. All patients enrolled were treated by the same treatment principle and measures. In patients of study group injection of pituitrin 0.017-0.042 U/min (1.0- 2.5 U/h) was given, and if hemodynamics was still unstable, catecholamines was added to obtain the target blood pressure; while in the control group catecholamines was given to maintain stability of hemodynamics.

RESULTS

Among 139 patients enrolled in the study, 66 composed of the clinical study group and 73 in the control group. The main principle of the treatment in the two groups was similar. There was no significant difference in overall 28-day mortality rate between study group and control group (40.9% vs. 46.6%, P > 0.05). In patients whose acute physiology and chronic health evaluation II ( APACHE II ) score was less than 25, the mortality of study group was significantly lower than that of control group [10.3% (3/29) vs. 35.7% (10/28), P < 0.05]. The length of stay in intensive care unit [ICU, days: 5(3,8) vs. 5(3,8)], and duration of mechanical ventilation [days: 4.0 (2.8, 6.0) vs. 4.0 (2.0, 5.0)] were similar in two groups (both P > 0.05). The dosage of NE (μg/min: 7.99 ± 5.02 vs. 10.12 ± 5.12) and heart rate (beat/min: 93.27 ± 7.84 vs. 108.45 ± 12.31) were significantly lower in study group compared with that of control group (both P < 0.05). Serum creatinine and lactate levels in the two groups were similar at baseline, and creatinine [μmol/L: 87.5 (62.8, 157.0) vs. 76.0 (52.5, 117.0)] and lactate level (mmol/L: 3.72 ± 2.47 vs. 3.53 ± 1.86) were still similar in two groups 24 hours later (all P > 0.05). The rate of use of glucocorticoid (43.9% vs. 31.5%) and heparin in small dosage (42.4% vs. 41.1%) had no significant difference between two groups (both P > 0.05).

CONCLUSIONS

Combined use of pituitrin in patients with septic shock can reduce the dosage of catecholamines, and decrease the heart rate. Although it can not lower the overall mortality of septic shock, among patients with less severity whose APACHE II score lower than 25, low-dose pituitrin in conjunction with catecholamine vasopressors can reduce 28-day mortality .

[Clinical manifestation and strategy for surgical resection and reconstruction of thoracolumbar vertebral osteoid osteoma]

OBJECTIVE

To investigate the clinical manifestation of thoracolumbar vertebral osteoid osteoma and to evaluate the surgical procedure and effectiveness of transpedicular tumor resection and spine reconstruction with posterior pedicle screw system and bone graft.

METHODS

Between January 2001 and June 2010, 8 cases of thoracolumbar vertebral osteoid osteoma underwent one-stage transpedicular intralesional excision and bone graft combined with spine reconstruction with pedicle screw system through posterior approach. There were 5 males and 3 females with a median age of 15.5 years (range, 6-27 years). Affected segments included T8 in 1 case, T10 in 1 case, L2 in 2 cases, L3 in 1 case, L4 in 1 case, and L5 in 2 cases. All of the cases had back pain, 1 had radiating pain of lower extremity, and 4 patients presented with scoliosis. The mean diameter of lesions was 1.6 cm (range, 0.9-2.0 cm).

RESULTS

The mean operation time was 110 minutes (range, 70-170 minutes) and the mean blood loss was 720 mL (range, 300-1 400 mL). The postoperative pathologic examination showed osteoid osteoma in all cases. All patients achieved healing of the incisions by first intention. Immediate relief of pain was observed after operation in all patients without complication. The patients were followed up 12-58 months (mean, 39 months). No local recurrence or spinal deformity was observed during the follow-up.

CONCLUSION

CT can show a low attenuation nidus with central mineralization and varying degrees of perinidal sclerosis, so it has great value for final diagnosis of thoracolumbar vertebral osteoid osteoma. One-stage transpedicular intralesional excision supplemented by impaction bone graft and combined posterior pedicle screw stabilization is a safe and effective treatment.

Common deficiencies with bioequivalence submissions in abbreviated new drug applications assessed by FDA

PURPOSE

A generic product must meet the standards established by the Food and Drug Administration (FDA) to be approved for marketing in the USA. FDA approves a generic product for marketing if it is proved to be therapeutically equivalent to the reference product. Bioequivalence (BE) between a proposed generic product and its corresponding reference product is one of the major components of therapeutic equivalence. These approvals may be delayed if the BE portion of the submission is determined to be deficient. Many of these BE deficiencies recur commonly and can be avoided.

METHOD

We conducted a survey of the BE submissions to abbreviated new drug applications (ANDAs) over years 2001 to 2008 to identify the most commonly occurring BE deficiencies.

RESULTS

Recurring deficiencies are found in a majority of the ANDAs reviewed by FDA's Division of Bioequivalence. The most common deficiencies were the two deficiencies related to dissolution (method and specifications) found in 23.3% of the applications and analytical method validation and/or report found in 16.5% of the applications. The approval of generic drugs would be greatly accelerated if these deficiencies could be avoided.

Bone marrow stromal cells produce long-term pain relief in rat models of persistent pain

Chronic pain conditions are difficult to treat and are major health problems. Bone marrow stromal cells (BMSCs) have generated considerable interest as a candidate for cell-based therapy. BMSCs are readily accessible and are easy to isolate and expand ex vivo. Clinical studies show that direct injection of BMSCs does not produce unwanted side effects and is well tolerated and safe. Here, we show that a single systemic (intravenous) or local injection (into the lesion site) of rat primary BMSCs reversed pain hypersensitivity in rats after injury and that the effect lasted until the conclusion of the study at 22 weeks. The pain hypersensitivity was rekindled by naloxone hydrochloride, an opioid receptor antagonist that acts peripherally and centrally, when tested at 1-5 weeks after BMSC infusion. In contrast, naloxone methiodide, a peripherally acting opioid receptor antagonist, only rekindled hyperalgesia in the first 3 weeks of BMSC treatment. Focal downregulation of brainstem mu opioid receptors by RNA interference (RNAi) reversed the effect of BMSCs, when RNAi was introduced at 5- but not 1-week after BMSC transplantation. Thus, BMSCs produced long-term relief of pain and this effect involved activation of peripheral and central opioid receptors in distinct time domains. The findings prompt studies to elucidate the cellular mechanisms of the BMSC-induced pain relieving effect and translate these observations into clinical settings.

Activation of group I mGlu receptors contributes to facilitation of NMDA receptor membrane current in spinal dorsal horn neurons after hind paw inflammation in rats

The interaction between the group I metabotropic glutamate (mGlu) receptors and N-methyl-D-aspartate (NMDA) receptors plays a critical role in spinal hyperexcitability and hyperalgesia. The cellular mechanisms underlying this interaction remain unknown. Utilizing an ex vivo spinal slice preparation from young adult rats, we investigated the group I mGlu receptor modulation of NMDA receptor-mediated current in superficial dorsal horn neurons by patch clamp recording after complete Freund's adjuvant (CFA)-induced hind paw inflammation. We show that NMDA receptor-mediated dorsal root stimulation-evoked EPSC (eEPSC) and NMDA-induced current was enhanced in the inflamed rats, compared to naïve rats and this effect was attenuated by AIDA (1 mM), a group I mGlu receptor antagonist. There were also increases in the frequency and amplitude of miniature excitatory postsynaptic currents in the presence of tetrodotoxin, suggesting enhanced presynaptic glutamate release probability and postsynaptic membrane responsiveness in inflamed rats. DHPG (10 μM), a selective group I mGlu receptor agonist, further facilitated NMDA receptor-mediated eEPSC and NMDA-induced current in inflamed rats. The DHPG-produced facilitation of NMDA-induced current was blocked by intracellular dialysis of GDP-beta-S (1 mM), a G protein antagonist, and BAPTA (15 mM), an intracellular calcium chelating agent; and by pretreatment with U73,122 (10 μM), a PLC inhibitor, or 2-APB (100 μM), an IP₃-receptor antagonist. These findings support the hypothesis that signal transduction coupling between group I mGlu receptors and NMDA receptors underlies the activation of NMDA receptors in spinal hyperexcitability and hyperalgesia.

Spinal 5-HT(3) receptor activation induces behavioral hypersensitivity via a neuronal-glial-neuronal signaling cascade

Recent studies indicate that the descending serotonin (5-HT) system from the rostral ventromedial medulla (RVM) in the brainstem and the 5-HT(3) receptor subtype in the spinal dorsal horn are involved in enhanced descending pain facilitation after tissue and nerve injury. However, the mechanisms underlying the activation of the 5-HT(3) receptor and its contribution to facilitation of pain remain unclear. In the present study, activation of spinal 5-HT(3) receptor by intrathecal injection of a selective 5-HT(3) receptor agonist, SR57227, induced spinal glial hyperactivity, neuronal hyperexcitability, and pain hypersensitivity in rats. We found that there was neuron-to-microglia signaling via chemokine fractalkine, microglia to astrocyte signaling via the cytokine IL-18, astrocyte to neuronal signaling by IL-1β, and enhanced activation of GluN (NMDA) receptors in the spinal dorsal horn. In addition, exogenous brain-derived neurotrophic factor-induced descending pain facilitation was accompanied by upregulation of CD11b and GFAP expression in the spinal dorsal horn after microinjection in the RVM, and these events were significantly prevented by functional blockade of spinal 5-HT(3) receptors. Enhanced expression of spinal CD11b and GFAP after hindpaw inflammation was also attenuated by molecular depletion of the descending 5-HT system by intra-RVM Tph-2 shRNA interference. Thus, these findings offer new insights into the cellular and molecular mechanisms at the spinal level responsible for descending 5-HT-mediated pain facilitation during the development of persistent pain after tissue and nerve injury. New pain therapies should focus on prime targets of descending facilitation-induced glial involvement, and in particular the blocking of intercellular signaling transduction between neuron and glia.

The effects of opioid receptor antagonists on electroacupuncture-produced anti-allodynia/hyperalgesia in rats with paclitaxel-evoked peripheral neuropathy

Research supports the effectiveness of acupuncture for conditions such as chronic low back and knee pain. In a five-patient pilot study the modality also improved the symptoms of chemotherapy-induced neuropathic pain. Using an established rat model of paclitaxel-induced peripheral neuropathy, we evaluated the effect of electroacupuncture (EA) on paclitaxel-induced hyperalgesia and allodynia that has not been studied in an animal model. We hypothesize that EA would relieve the paclitaxel-induced mechanical allodynia and hyperalgesia, which was assessed 30 min after EA using von Frey filaments. Beginning on day 13, the response frequency to von Frey filaments (4-15 g) was significantly increased in paclitaxel-injected rats compared to those injected with vehicle. EA at 10 Hz significantly (P<0.05) decreased response frequency at 4-15 g compared to sham EA; EA at 100 Hz only decreased response frequency at 15 g stimulation. Compared to sham EA plus vehicle, EA at 10 Hz plus either a μ, δ, or κ opioid receptor antagonist did not significantly decrease mechanical response frequency, indicating that all three antagonists blocked EA inhibition of allodynia and hyperalgesia. Since we previously demonstrated that μ and δ but not κ opioid receptors affect EA anti-hyperalgesia in an inflammatory pain model, these data show that EA inhibits pain through different opioid receptors under varying conditions. Our data indicate that EA at 10 Hz inhibits mechanical allodynia/hyperalgesia more potently than does EA at 100 Hz. Thus, EA significantly inhibits paclitaxel-induced allodynia/hyperalgesia through spinal opioid receptors, and EA may be a useful complementary treatment for neuropathic pain patients.

Early detection and treatment of wear particle-induced inflammation and bone loss in a mouse calvarial osteolysis model using HPMA copolymer conjugates

Wear particle-induced inflammation is considered to be the major cause of aseptic implant loosening and clinical failure after total joint replacement. Due to the frequent absence of symptoms, early detection and intervention prior to implant failure presents a significant challenge. To address this issue, a N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-based optical imaging contrast agent (P-IRDye) was developed and used for the detection of wear particle-induced inflammation employing a murine calvaria osteolysis model. The particle-induced osteolysis of calvaria was evaluated by H&E, tartrate-resistant acid phosphatase (TRAP) staining and μ-CT after necropsy. One-day post particle implantation, P-IRDye was administrated to the mice via tail vein injection. Live imaging of the animals 6 days after implantation revealed the preferential distribution and sustained retention of the macromolecular contrast agent at the site of particle implantation. Immunohistochemical staining and FACS analyses of the calvaria-associated soft tissue revealed extensive uptake of the HPMA copolymer by F4/80, Ly-6G (Gr1) and CD11c positive cells, which accounts for the retention of the macromolecular probes at the inflammatory sites. To test the potential of the system for therapeutic intervention, an acid-labile HPMA copolymer-dexamethasone conjugate (P-Dex) was prepared and shown to prevent the particle-induced inflammation and bone damage in the calvaria osteolysis model.

[The operative treatment of Ruedi II-III Pilon fractures with the ventr-lateral approach]

OBJECTIVE

To investigate the effects of the ventralateral approach in treating severe Pilon fracture.

METHODS

From February 2002 to March 2008, 63 patients with Ruedi II-III Pilon fractures were treated with the ventralateral approach, including 36 males and 27 females with an average age of 37 years ranging from 19 to 71 years. The mean time from injury to operation was 8 days (ranged for 2 h-19 d). According to the Ruedi classification system, type II was 32 cases (6 cases of them combined with soft tissue lesion, 4 with open fracture) and type III was 31 cases (9 cases of them combined with soft tissue lesion, 8 with open fracture). The clinical effects were evaluated according to Helfet criteria and the complications were observed including condition of wound healing, infection, bone union, deformity union, motion of the ankle, the degree of the pain and so on.

RESULTS

The first intention achieved in 59 cases, the delayed healing in 4 cases. Stiffness of the ankle was found in 5 cases because of bone disunion. All patients were followed up from 8 to 31 months with an average of 15.3 months. The ranging in bone healing time was from 8 to14 weeks with an average of 10 weeks. According to the Helfet criteria, 28 cases obtained excellent results, 30 good, 5 poor.

CONCLUSION

The operative treatment of Ruedi I-III Pilon fractures with the ventralateral approach can obtain satisfactory results and avoid complications effectively.

Serotonin Receptor 2A/C Is Involved in Electroacupuncture Inhibition of Pain in an Osteoarthritis Rat Model

Osteoarthritis currently has no cure. Acupuncture can benefit patients with knee osteoarthritis by providing pain relief, improving joint function and serving as an effective complement to standard care. However, the underlying mechanisms of its effects are still not completely understood. The present study, an investigation of the effectiveness and mechanisms of electroacupuncture (EA) in attenuating osteoarthritis pain in a rat model, is focused on the involvement of 5-hydroxytryptamine 2A/C (5-HT2A/C) receptors, which play an important role in pain modulation at the spinal level. Osteoarthritis was induced under isoflurane anesthesia by a single intraarticular injection of monosodium iodoacetate (3 mg/50 μL/rat) into one hind leg of each rat. EA was given at acupoints GB 30 and ST 36 on days 1–4 after the injection. Vehicle or ketanserin, a 5-HT2A/C receptor antagonist, was given intraperitoneally (1 mg kg⁻¹) or intrathecally (5 μg or 10 μg/10 μL), 30 min before each EA treatment. Assessment of weight-bearing difference between injected and uninjected hind legs was done on days 0, 1–4 and 7. Fos /serotonin and serotonin/Fluorogold double labeling were performed to determine EA activation of serotonergic neurons in the nucleus raphe magnus (NRM) that project to spinal cord. The results showed that EA significantly decreases weight-bearing difference compared to sham EA. Ketanserin pretreatment blocked the analgesic effect of EA but did not influence weight bearing in sham EA control rats. EA also activated serotonergic NRM neurons that project to the spinal cord. These data show that EA inhibits osteoarthritis-induced pain by enhancing spinal 5-HT2A/2C receptor activity.

Enhanced aqueous solubility and bioavailability of capsaicin by the preparation of an inclusion complex

To increase the aqueous solubility and poor bioavailability of capsaicin (CAS 404-86-4), in this paper, the effects of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on the aqueous solubility and the pharmacokinetic characteristics of capsaicin were investigated. The corresponding inclusion complex of capsaicin/HP-beta-CD at the molar ratio of 1:1 was obtained by the method of saturated aqueous solution and characterized by differential scanning calorimetry and X-ray diffractometry. The dissolution rate of capsaicin was significantly increased by the complexation with HP-beta-CD, due to its solubilizing activity. The absorption behavior and bioavailability of capsaicin and its complexation were evaluated after their subcutaneous (s.c.) injection in rats. The absorption rates of capsaicin across subcutaneous tissues and its bioavailability were significantly enhanced by the formation of an inclusion complex with HP-beta-CD. The present results indicate the potential of utilizing HP-beta-CD to improve the subcutaneous absorption and bioavailability of capsaicin.

Lipid nanoparticles loaded with 10-hydroxycamptothecin-phospholipid complex developed for the treatment of hepatoma in clinical application

For the purpose of clinical intravenous injection of 10-hydroxycamptothecin, a novel formulation of lipid nanoparticles loaded with 10-hydroxycamptothecin-phospholipid complex (HCPT-PC-LNs) was prepared by solvent evaporation and high-pressure homogenization methods. Spherical particles with a mean particle size of 200 nm and high encapsulation efficiency of 97.39 +/- 0.91% could be achieved under optimal conditions. In vitro release profile showed that the release pattern of HCPT from nanoparticles was retarded with neglectable initial burst release and well-fitted to Ritger-Peppas equation. In vivo distribution studies in mice showed that HCPT-PC-LNs were mainly localized in liver. Besides, in situ mouse hepatoma model was established and tumor uptake of HCPT-PC-LNs was much higher than that of free HCPT (more than 18-fold). It was found that HCPT-PC-LNs exhibited high growth inhibitory effect on human liver cancer cells by MTT assay. The cellular uptake of HCPT was 24.33 +/- 1.30 x 10(-7) microg/cell in HCPT-PC-LNs treated group at 12 h, which was almost 14-fold higher than that of free HCPT (1.72 +/- 0.57 x 10(-7) microg/cell). This study suggested that the HCPT-PC-LNs could be utilized as a novel formulation for liver tumors therapy, which might be applied in clinic in the near future.