Platelet-derived growth factor receptor-α induces contraction knots and inflammatory pain-like behavior in a rat model of myofascial trigger points.

BACKGROUND: Myofascial trigger points (MTrPs) are the primary etiological characteristics of chronic myofascial pain syndrome (MPS). Receptor tyrosine kinases (RTKs) are associated with signal transduction in the central mechanisms of chronic pain but the role of RTKs in the peripheral mechanisms of MTrPs remains unclear. The present study aimed to identify RTKs expression in MTrPs and elucidate the molecular mechanisms through which platelet-derived growth factor receptor-α (PDGFR-α) induces contraction knots and inflammatory pain-like behavior in a rat model of myofascial trigger points. METHODS: MTrPs tissue samples were obtained from the trapezius muscles of patients with MPS through needle biopsy, and PDGFR-α activation was analyzed by microarray, enzyme-linked immunosorbent assay (ELISA), and histological staining. Sprague-Dawley (SD) rats (male/female) were used to investigate PDGFR-α signaling, assessing pain-like behaviors with Randall-Selitto and nest-building tests. Muscle fiber and sarcomere morphologies were observed using histology and electron microscopy. The PDGFR-α binding protein was identified by co-immunoprecipitation (Co-IP), liquid chromatograph mass spectrometer (LC-MS), and molecular docking. PDGFR-α-related protein or gene levels, muscle contraction, and inflammatory markers were determined by Western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RESULTS: PDGFR-α phosphorylation levels were elevated in the MTrPs tissues of individuals with trapezius muscle pain and were positively correlated with pain intensity. In rats, PDGFR-α activation caused pain-like behaviors and muscle contraction via the janus kinase 2/signal transducer and activator of transcription-3 (JAK2/STAT3) pathway. JAK2/STAT3 inhibitors reversed the pain-like behaviors and muscle contraction induced by PDGFR-α activation. Collagen type I alpha 1 (COL1A1) binds to PDGFR-α and promotes its phosphorylation, which contributed to pain-like behaviors and muscle contraction. CONCLUSIONS: COL1A1-induced phosphorylation of PDGFR-α and the subsequent activation of the JAK2/STAT3 pathway may induce dysfunctional muscle contraction and increased nociception at MTrPs.

Optimal postoperative delirium prediction after coronary artery bypass grafting surgery: a prospective cohort study.

Background: Postoperative delirium (POD) presents as a serious neuropsychiatric syndrome in patients undergoing off-pump coronary artery bypass grafting (OPCABG) surgery. This is correlated with higher mortality, cognitive decline, and increased costs. The Age-adjusted Charlson Comorbidity Index (ACCI) is recognized as an independent predictor for mortality and survival rate. The purpose of our study is to estimate the predictive value of the ACCI on the POD in patients undergoing OPCABG surgery. Methods: This prospective cohort study enrolled patients undergoing OPCABG surgery between December 2020 and May 2021 in Qilu Hospital. Patients were divided into the low-ACCI group (score, 0-3) and the high-ACCI group (score ≥4) according to their ACCI scores. The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) and CAM were used to diagnose POD within 7 days after surgery. The general, laboratory, and clinical data of the patients were recorded and collected. The characteristic ROC curve was applied to further assess the predictive value of the ACCI for POD in patients following OPCABG surgery. Results: A total of 89 patients were enrolled, including 45 patients in the low-ACCI group and 44 patients in the high-ACCI group. The incidence of POD was higher in the high-ACCI group than in the low-ACCI group (45.5% vs. 15.6%, P = 0.003). Multivariate logistic regression analyses showed that the ACCI (OR, 2.433; 95% CI, 1.468-4.032; P = 0.001) was an independent risk factor for POD. The ACCI accurately predicted POD in patients following OPCABG surgery with an AUC of 0.738, and the Hosmer-Lemeshow goodness of fit test yielded X2 = 5.391 (P = 0.145). Conclusion: The high-ACCI group showed a high incidence of POD. The ACCI was an independent factor associated with POD in patients following OPCABG surgery. In addition, the ACCI could accurately predict POD in patients following OPCABG surgery. Clinical Trial Registration: ClinicalTrials.gov, identifier CHiCTR2100052811.

Autoinhibitory mechanism controls binding of centrosomin motif 1 to γ-tubulin ring complex.

The γ-tubulin ring complex (γTuRC) is the principal nucleator of cellular microtubules, and the microtubule-nucleating activity of the complex is stimulated by binding to the γTuRC-mediated nucleation activator (γTuNA) motif. The γTuNA is part of the centrosomin motif 1 (CM1), which is widely found in γTuRC stimulators, including CDK5RAP2. Here, we show that a conserved segment within CM1 binds to the γTuNA and blocks its association with γTuRCs; therefore, we refer to this segment as the γTuNA inhibitor (γTuNA-In). Mutational disruption of the interaction between the γTuNA and the γTuNA-In results in a loss of autoinhibition, which consequently augments microtubule nucleation on centrosomes and the Golgi complex, the two major microtubule-organizing centers. This also causes centrosome repositioning, leads to defects in Golgi assembly and organization, and affects cell polarization. Remarkably, phosphorylation of the γTuNA-In, probably by Nek2, counteracts the autoinhibition by disrupting the γTuNA‒γTuNA-In interaction. Together, our data reveal an on-site mechanism for controlling γTuNA function.

Application of the (fr)AGILE scale in the evaluation of multidimensional frailty in elderly inpatients from internal medicine wards: a cross-sectional observational study.

Background: With the rapid growth of an aging global population and proportion, the prevalence of frailty is constantly increasing. Therefore, finding a frailty assessment tool suitable for clinical application by physicians has become the primary link in the comprehensive management of frailty in elderly patients. This study used the (fr)AGILE scale to investigate the frailty status of elderly patients from internal medicine wards and identified relevant factors that affect the severity of frailty. Method: In this study, 408 elderly inpatients in internal medicine departments of Qilu Hospital of Shandong University from May 2021 to August 2022 were enrolled as research subjects, and a cross-sectional observational study was conducted. Researchers evaluated the frailty based on the (fr)AGILE scale score. The general condition, past medical history, physical examination, laboratory examination, nutrition control score, intervention and treatment measures and other elderly patient information was collected. Logistic regression analysis was used to analyze the relevant factors that affect the severity of frailty and hospitalization costs. Results: According to the (fr)AGILE scale score, the elderly patients were divided into groups to determine whether they were frail and the severity of the frailty. Among them, 164 patients were in the prefrailty stage, which accounted for 40.2%. There were 188 cases of mild frailty that accounted for 46.1%, and 56 cases of moderate to severe frailty that accounted for 13.7%. Decreased grip strength, elevated white blood cell levels, and low sodium and potassium are independent risk factors affecting the severity of frailty. As the severity of frailty increases, the proportion of sodium, potassium, albumin supplementation as well as anti-infection gradually increases. Conclusion: Frailty is a common elderly syndrome with a high incidence among elderly patients in internal medicine departments. The main manifestations of frailty vary with different severity levels. Inflammation, anemia, and poor nutritional status can lead to an increase in the severity of frailty as well as blood hypercoagulability, myocardial damage, and additional supportive interventions. This ultimately leads to prolonged hospitalization and increased hospitalization costs.

Impact of shift work on surgical outcomes at different times in patients with acute type A aortic dissection: A retrospective cohort study.

Background: To investigate the effect of shift work on surgical outcomes at different times in patients with acute type A aortic dissection (ATAAD). Materials and methods: Patients with ATAAD who underwent total arch replacement at Qilu Hospital of Shandong University from January 2015 to March 2022 were retrospectively analyzed. All patients were managed according to the green channel emergency management strategy, and a professional cardiac team was arranged during off-hours. Based on surgery time and symptom onset to procedure time, the patients were divided into weekday, weekend and holiday groups; daytime and nighttime groups; intervention time ≤48 h and >48 h groups; working hours and off-hours groups. In-hospital mortality between these groups was compared. Results: In total, 499 ATAAD patients underwent surgery within 7 days of symptom onset, and the in-hospital mortality rate was 10% (n = 50/499). Among the 499 patients, 320 (64.13%), 128 (25.65%) and 51 (10.22%) underwent surgery on weekdays, weekends and holidays, respectively. In-hospital mortality and 7-day mortality showed no significant difference among the three groups. Two hundred twenty-seven (45.5%) underwent daytime surgery, and 272 (54.5%) underwent nighttime surgery. Durations of ICU stay and hospital stay were significantly different between the two groups (P < 0.05). There was no significant differences in in-hospital mortality (9.2% vs. 10.7%) and 7-day mortality (4.4% vs. 6.6%). 221 patients (44.3%) and 278 patients (55.7%) were included in the intervention time ≤48 h and >48 h groups, respectively. Acute renal injury, ICU stay and hospital stay were significantly different (P < 0.05) whereas 7-day mortality (5.0% vs. 6.1%) and in-hospital mortality (8.6% vs. 11.1%) were not. Furthermore, 7-day (1.9% vs. 6.6%) and in-hospital mortality (11.1% vs. 9.8%) showed no difference between working hours group (n = 108) and off-hours group (n = 391). Cox regression analysis showed that postoperative acute renal injury (HR = 2.423; 95% CI, 1.214-4.834; P = 0.012), pneumonia (HR = 2.542; 95% CI, 1.186-5450; P = 0.016) and multiple organ dysfunction (HR = 11.200; 95% CI, 5.549-22.605; P = 0.001) were the main factors affecting hospital death in ATAAD patients. Conclusion: Under the management of a professional cardiac surgery team with dedicated off-hours shifts, surgery time was not related to in-hospital mortality in ATAAD patients.

Surgical Masks Affect the Peripheral Oxygen Saturation and Respiratory Rate of Anesthesiologists.

Background: Surgical masks (SMs) protect medical staff and reduce surgical site infections. Extended SM use may reduce oxygen concentrations in circulation, causing hypoxia, headache, and fatigue. However, no research has examined the effects of wearing SMs on oxygenation and physical discomfort of anesthesiologists. Methods: An electronic questionnaire was established and administered through WeChat, and a cross-sectional survey was conducted to determine SM use duration and related discomfort of operating room medical staff. Then, operating room anesthesiologists were enrolled in a single-arm study. Peripheral blood oxygen saturation (SpO2), heart rate, and respiratory rate were determined at different times before and after SM use. Shortness of breath, dizziness, and headache were subjectively assessed based on the visual analog scale (VAS) scores. Results: In total, 485 operating room medical staff completed the electronic questionnaire; 70.5% of them did not change SMs until after work, and 63.9% wore SMs continuously for more than 4 h. The proportion of anesthesiologists was the highest. After wearing masks for 4 h, the shortness of breath, fatigue, and dizziness/headache rates were 42.1, 34.6, and 30.9%, respectively. Compared with other medical staff, the proportion of subjective discomfort of anesthesiologists increased significantly with prolonged SM use from 1 to 4 h. Thirty-five anesthesiologists completed the study. There was no difference in anesthesiologist SpO2, heart rate, or respiratory rate within 2 h of wearing SMs. After more than 2 h, the variation appears to be statistically rather than clinically significant-SpO2 decreased (98.0 [1.0] vs. 97.0 [1.0], p < 0.05), respiratory rate increased (16.0 [3.0] vs. 17.0 [2.0], p < 0.01), and heart rate remained unchanged. As mask use duration increased, the VAS scores of shortness of breath, dizziness, and headache gradually increased. Conclusion: In healthy anesthesiologists, wearing SMs for more than 2 h can significantly decrease SpO2 and increase respiratory rates without affecting heart rates.

Impact of intravenous dexmedetomidine on postoperative bowel movement recovery after laparoscopic nephrectomy: A consort-prospective, randomized, controlled trial.

BACKGROUND: Postoperative ileus is a frequent postoperative complication, especially after abdominal surgery. Sympathetic excitation is the primary factor for postoperative ileus. Sympathetic activation becomes increased by surgical stress, postoperative pain, and inflammation. Dexmedetomidine (DEX) can inhibit sympathetic nerve activity, inflammation, and pain. AIM: To observe whether DEX promotes bowel movements in patients after laparoscopic nephrectomy. METHODS: One hundred and twenty patients undergoing laparoscopic nephrectomy were assigned to three groups: C (normal saline infusion), D1 (DEX 0.02 µg/kg/h), and D2 (DEX 0.04 µg/kg/h). The primary outcomes were the recorded times to first flatus, defecation, and eating after surgery. The secondary outcomes were postoperative pain, assessed using the numerical rating scale (NRS), adverse effects, and the duration of the postoperative hospital stay. RESULTS: The times to first flatus, defecation, and eating in groups D1 and D2 were significantly shorter than those in group C (P < 0.01). The NRS scores at 8 h and 24 h after surgery were significantly lower in groups D1 and D2 than in group C (P < 0.05). No adverse effects were observed (P > 0.05). CONCLUSION: Postoperative infusion of DEX at 0.04 µg/kg/h facilitates bowel movements in patients undergoing laparoscopic nephrectomy.

Sevoflurane and isoflurane inhibit KCl-induced, Rho kinase-mediated, and PI3K-participated vasoconstriction in aged diabetic rat aortas.

BACKGROUND: The mechanism of volatile anesthetics on vascular smooth muscle (VSM) contraction in the setting of diabetes mellitus (DM) remains unclear. The current study was designed to determine the effects of sevoflurane (SEVO) and isoflurane (ISO) on phosphoinositide 3-kinase (PI3K) and Rho kinase (ROCK) mediated KCl-induced vasoconstriction in aged type 2 diabetic rats. METHODS: KCl-induced (60 mM) contractions were examined in endothelium-denuded aortic rings from aged T2DM Otsuka Long-Evans Tokushima Fatty (OLETF) rats (65-70 weeks old), control age-matched nondiabetic Long-Evans Tokushima Otsuka (LETO) rats and young Wistar rats (6-8 weeks old). The effects of SEVO or ISO (1-3 minimum alveolar concentration, MAC) on KCl-induced vasoconstriction, as well as those of LY294002 (PI3K inhibitor) and Y27632 (ROCK inhibitor) were measured in aortic rings from the three groups using an isometric force transducer. RESULTS: KCl induced rapid and continuous contraction of aortic smooth muscle in the three groups, and the contraction was more obvious in OLETF rats. SEVO and ISO inhibited KCl-induced vasoconstriction in a concentration-dependent manner and were suppressed by LY294002 (10 µM) and Y27632 (1 µM). SEVO had a stronger inhibitory effect on the aortas of young Wistar rats than ISO, especially at 2 MAC and 3 MAC (P < 0.05). In aged rats, the inhibitory effect of ISO was stronger than that of SEVO, especially OLETF rats. There was no significant difference in the effects of different concentrations of ISO on arterial contraction among the three groups (P > 0.05). The effects of 1 MAC SEVO on Wistar rats and 3 MAC SEVO on OLETF rats, however, were noticeably and significantly different (P < 0.05). Compared with the control condition, LY294002 and Y27632 had the most noticeable effect on the KCl-induced contraction of aortic rings in OLETF rats (P < 0.01). CONCLUSION: SEVO (3 MAC), ISO (1, 2, 3 MAC), LY294002 and Y27632 have more significant inhibitory effect on the contraction of vascular smooth muscle in aged T2MD rats. The mechanism of SEVO and ISO in vascular tension in T2DM is partly due to changes in PI3K and/or Rho kinase activity.

Awake fiberoptic intubation and use of bronchial blockers in ankylosing spondylitis patients.

BACKGROUND: Patients with ankylosing spondylitis (AS) combined with severe cervical fusion deformity have difficult airways. Awake fiberoptic intubation is the standard treatment for such patients. Alleviating anxiety and discomfort during intubation while maintaining airway patency and adequate ventilation is a major challenge for anesthesiologists. Bronchial blockers (BBs) have significant advantages over double-lumen tubes in these patients requiring one-lung ventilation. AIM: To evaluate effective drugs and their optimal dosage for awake fiberoptic nasotracheal intubation in patients with AS and to assess the pulmonary isolation effect of one-lung ventilation with a BB. METHODS: We studied 12 AS patients (11 men and one woman) with lung or esophageal cancer who underwent thoracotomy with a BB. Preoperative airway evaluation found that all patients had a difficult airway. All patients received an intramuscular injection of penehyclidine hydrochloride (0.01 mg/kg) before anesthesia. In the operating room, dexmedetomidine(0.5 µg/kg) was infused intravenously for 10 min, with 2% lidocaine for airway surface anesthesia, and a 3% ephedrine cotton swab was used to contract the nasal mucosa vessels. Before tracheal intubation, fentanyl (1 µg/kg) and midazolam (0.02 mg/kg) were administered intravenously. Awake fiberoptic nasotracheal intubation was performed in the semi-reclining position. Intravenous anesthesia was administered immediately after successful intubation, and a BB was inserted laterally. The pre-intubation preparation time, intubation time, facial grimace score, airway responsiveness score during the fiberoptic introduction, time of end tracheal catheter entry into the nostril, and lung collapse and surgical field score were measured. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were recorded while entering the operation room (T1), before intubation (T2), immediately after intubation (T3), 2 min after intubation (T4), and 10 min after intubation (T5). After surgery, all patients were followed for adverse reactions such as epistaxis, sore throat, hoarseness, and dysphagia. RESULTS: All patients had a history of AS (20.4 ± 9.6 years). They had a Willson's score of 5 or above, grade III or IV Mallampati tests, an inter-incisor distance of 2.9 ± 0.3 cm, and a thyromental (T-M) distance of 4.8 ± 0.7 cm. The average pre-intubation preparation time was 20.4 ± 3.4 min, intubation time was 2.6 ± 0.4 min, facial grimace score was 1.7 ± 0.7, airway responsiveness score was 1.1 ± 0.7, and pulmonary collapse and surgical exposure score was 1.2 ± 0.4. The SBP, DBP, and HR at T5 were significantly lower than those at T1-T4 (P < 0.05). While the values at T1 were not significantly different from those at T2-T4 (P > 0.05), they were significantly different from those at T5 (P < 0.05). Seven patients had minor epistaxis during endotracheal intubation, two were followed 24 h after surgery with a mild sore throat, and two had hoarseness without dysphagia. CONCLUSION: Patients with AS combined with severe cervical and thoracic kyphosis should be intubated using fiberoptic bronchoscopy under conscious sedation and topical anesthesia. Proper doses of penehyclidine hydrochloride, dexmedetomidine, fentanyl, and midazolam, combined with 2% lidocaine, administered prior to intubation, can provide satisfactory conditions for tracheal intubation while maintaining the comfort and safety of patients. BBs are safe and effective for one-lung ventilation in such patients during thoracotomy.

Green and facile fabrication of porous titanium dioxide as efficient sulfur host for advanced lithium-sulfur batteries: An air oxidation strategy.

Lithium-sulfur (Li-S) battery has been considered a promising next-generation electrochemical energy storage device due to its high theoretical capacity and high energy density. However, the dissolution and shuttling problems of lithium polysulfides (LiPSs) are major obstacles hindering the performance and application of Li-S batteries. To address these issues, we report the rapid preparation of porous TiO2 nanoparticles (p-TiO2-NPs) as an effective sulfur host for Li-S batteries using a facile, scalable, and green one-step air oxidation strategy. Experimental results reveal that the p-TiO2-NPs have a mesopores-rich structure and strong chemical adsorption capability against LiPSs, which effectively mitigates the dissolution and shuttling of LiPSs by way of physical and chemical adsorptions. Incorporating highly conductive multi-wall carbon nanotubes to interconnect with the active materials, the p-TiO2-NPs-based cathode delivers a high discharge capacity of 1276 mAh g-1 at 0.2 C and stable cycling performance with an ultralow capacity decay rate of 0.0526% per cycle at 1 C over 1200 cycles. This green and facile fabrication strategy can also be extended to other metal carbides to endow an environmentally friendly route for the sustainable development of high-performance Li-S batteries.

Analgesia in acute ischemic chest pain.

Analgesics, particularly opioids, have been routinely used in the emergency treatment of ischemic chest pain for a long time. In the past two decades; however, several studies have raised the possibility of the harmful effects of opioid administration. In 2014, the American Heart Association (AHA)/American College of Cardiology Foundation (ACCF) changed the guidelines regarding the use of opioids from class IC to class IIb for non-ST elevation acute coronary syndrome. And in 2015, the European Society of Cardiology (ESC) guidelines incidentally noted the side effects of opioids. In ST-segment elevation myocardial infarction, both ESC and AHA/ACCF still recommend the use of opioids. Given the need for adequate pain relief in ischemic chest pain in the emergency setting, it is necessary to understand the adverse effects of analgesia, while still providing sufficiently potent options for analgesia. The primary purpose of this review is to quantify the effects of analgesics commonly used in the prehospital and emergency department in patients with ischemic chest pain.

Analgesic effect of parecoxib combined with ropivacaine in patients undergoing laparoscopic hepatectomy.

BACKGROUND: Currently, there is no uniform standard for analgesia during laparoscopic hepatectomy. Most of the analgesia schemes adopt epidural analgesia after laparotomy. Although the analgesia is effective, it has a great impact on the recovery of patients after laparoscopic hepatectomy and is not completely suitable for analgesia after laparoscopic hepatectomy. Although multimodal perioperative analgesia can significantly relieve postoperative pain, there is no relevant study of parecoxib combined with ropivacaine for post-laparoscopic hepatectomy analgesia. AIM: To study the analgesic effect of the preoperative intravenous injection of parecoxib combined with long-acting local anesthetic ropivacaine for incision infiltration in patients undergoing laparoscopic hepatectomy. METHODS: Forty-eight patients undergoing laparoscopic hepatectomy were randomly divided into a combined group (parecoxib combined with ropivacaine) and a control group. The visual analogue scale (VAS) at rest and during movement was used to compare the analgesic effect of the two groups. Meanwhile, the cumulative sufentanil, the recovery time for enterokinesia, the length of postoperative hospital stay, and the adverse reactions (nausea and vomiting) were recorded and compared between the two groups. RESULTS: The change tendency in VAS scores for both groups was similar after operation. At rest, the VAS scores of the combined group were significantly lower than those of the control group at 0, 6, 12, 24 and 36 h, and during movement, the VAS scores of the combined group were significantly lower than those of the control group at 0, 6, 12, and 24 h. The recovery time for enterokinesia in the combined group was 2.9 d, which was significantly shorter than that in the control group. The cumulative sufentanil in the combined group decreased significantly at 24, 36, and 48 h after operation. CONCLUSION: Preoperative intravenous injection of parecoxib combined with ropivacaine for incision infiltration is a simple and effective method for postoperative analgesia in laparoscopic hepatectomy, which could relieve pain and promote recovery.

A clarifying method that improves imaging of Aplysia ganglia.

Improvements in the imaging of neural circuits are essential for studies of network function in both invertebrates and vertebrates. Therefore, CLARITY, a new imaging enhancement technique developed for mouse brains has attracted broad interest from researchers working on other species. We studied the potential of a modified version of CLARITY to enhance the imaging of ganglia in an invertebrate Aplysia. For example, we have modified the hydrogel solution and designed a small container for the Aplysia ganglia. The ganglia were first processed for immunohistochemistry, and then for CLARITY. We examined the compatibility of these techniques and the extent to which the imaging of fluorescence improved using confocal microscopy. We found that CLARITY did indeed enhance the imaging of CP2 immunopositive neurons in Aplysia ganglia. For example, it improved visualization of small, weak immunoreactive neurons deep in the ganglia. Our modifications of CLARITY make this new method suitable for future use in Aplysia experiments. Furthermore, our techniques are likely to facilitate imaging in other invertebrate ganglia.

Microtubule plus-end tracking of end-binding protein 1 (EB1) is regulated by CDK5 regulatory subunit-associated protein 2.

Microtubules are polar cytoskeleton filaments that extend via growth at their plus ends. Microtubule plus-end-tracking proteins (+TIPs) accumulate at these growing plus ends to control microtubule dynamics and attachment. The +TIP end-binding protein 1 (EB1) and its homologs possess an autonomous plus-end-tracking mechanism and interact with other known +TIPs, which then recruit those +TIPs to the growing plus ends. A major +TIP class contains the SXIP (Ser-X-Ile-Pro, with X denoting any amino acid residue) motif, known to interact with EB1 and its homologs for plus-end tracking, but the role of SXIP in regulating EB1 activities is unclear. We show here that an interaction of EB1 with the SXIP-containing +TIP CDK5 regulatory subunit-associated protein 2 (CDK5RAP2) regulates several EB1 activities, including microtubule plus-end tracking, dynamics at microtubule plus ends, microtubule and α/ß-tubulin binding, and microtubule polymerization. The SXIP motif fused with a dimerization domain from CDK5RAP2 significantly enhanced EB1 plus-end-tracking and microtubule-polymerizing and bundling activities, but the SXIP motif alone failed to do so. An SXIP-binding-deficient EB1 mutant displayed significantly lower microtubule plus-end tracking than the wild-type protein in transfected cells. These results suggest that EB1 cooperates with CDK5RAP2 and perhaps other SXIP-containing +TIPs in tracking growing microtubule tips. We also generated plus-end-tracking chimeras of CDK5RAP2 and the adenomatous polyposis coli protein (APC) and found that overexpression of the dimerization domains interfered with microtubule plus-end tracking of their respective SXIP-containing chimeras. Our results suggest that disruption of SXIP dimerization enables detailed investigations of microtubule plus-end-associated functions of individual SXIP-containing +TIPs.

Sevoflurane and isoflurane inhibit KCl-induced Class II phosphoinositide 3-kinase α subunit mediated vasoconstriction in rat aorta.

BACKGROUND: Class II phosphoinositide 3-kinase α-isoform (PI3K-C2α) is involved in regulating KCl-induced vascular smooth muscle contraction. The current study was to investigate the effects of sevoflurane (SEVO) and isoflurane (ISO) on KCl-elicited PI3KC2α mediated vasoconstriction in rat aortic smooth muscle. METHODS: Isometric force, in the absence or presence of SEVO or ISO (1 ~ 3 minimum alveolar concentration, MAC), PI3K inhibitor LY294002, Rho kinase inhibitor Y27632, and membrane translocation of PI3K-p85, PI3K-C2α, Rho kinase (Rock II), or phosphorylation of MYPT1/Thr853, MYPT1/Thr696, CPI-17/Thr38 and MLC in response to KCl (60 mM) was measured by using isometric force transducer and western blotting analysis, respectively. RESULTS: KCl elicited a rapid and sustained contraction of rat aortic smooth muscle that was inhibited by both SEVO and ISO in a concentration-dependent manner, and also suppressed by LY294002 (1 mM) and Y27632 (1 uM). LY294002 (1 mM) and Y27632 (1 uM) also inhibited KCl-induced MLC phosphorylation. LY294002 (1 mM) inhibited KCl-induced PI3K-p85, PI3K-C2α membrane translocation in response to KCl (p <0.05, p < 0.01, respectively). Not only Y27632 (1 uM), but also LY294002 (1 mM), inhibited KCl-induced Rock-II membrane translocation (p < 0.01). SEVO and ISO inhibited KCl-stimulated MLC phosphorylation, PI3K-C2α and Rock-II,not PI3K p85 membrane translocation in a concentration-dependent manner in rat aorta. Both SEVO and ISO suppressed the MYPT1/Thr853, not MYPT1/Thr696 and CPI-17/Thr38, MLC phosphorylation in response to KCl. CONCLUSION: PI3K-C2α mediates part of SEVO and ISO-mediated vasodilation in rat aorta. The cellular mechanisms underlying the inhibitory effect of volatile anesthetics might be mediated by KCl/PI3K-C2α/Rho kinase/MYPT1/MLC pathway.

Long-term effect of ropivacaine nanoparticles for sciatic nerve block on postoperative pain in rats.

PURPOSE: The analgesic effect of ropivacaine (Rop) for nerve block lasts only ~3-6 hours for single use. The aim of this study was to develop long-acting regional anesthetic Rop nanoparticles and investigate the effects of sciatic nerve block on postoperative pain in rats. MATERIALS AND METHODS: Rop nanoparticles were developed using polyethylene glycol-co-polylactic acid (PELA). One hundred and twenty adult male Wistar rats were randomly divided into four groups (n=30, each): Con (control group; 0.9% saline, 200 µL), PELA (PELA group; 10 mg), Rop (Rop group; 0.5%, 200 µL), and Rop-PELA (Rop-PELA group; 10%, 10 mg). Another 12 rats were used for the detection of Rop concentration in plasma. The mechanical withdrawal threshold and thermal withdrawal latency were measured at 2 hours, 4 hours, 8 hours, 1 day, 2 days, 3 days, 5 days, and 7 days after incision. The expression of c-FOS was determined by immunohistochemistry at 2 hours, 8 hours, 48 hours, and 7 days. Nerve and organ toxicities were also evaluated at 7 days. RESULTS: The duration of Rop absorption in the plasma of the Rop-PELA group was longer (>8 hours) than that of the Rop group (4 hours). Mechanical withdrawal threshold and thermal withdrawal latency in the Rop-PELA group were higher than that in other groups (4 hours-3 days). c-FOS expression in the Rop-PELA group was lower than that in the control group at 2 hours, 8 hours, and 48 hours and lower than that in the Rop group at 8 hours and 48 hours after paw incision. Slight foreign body reactions were observed surrounding the sciatic nerve at 7 days. No obvious pathophysiological change was found in the major organs after Rop-PELA administration at 7 days. CONCLUSION: Rop-PELA provides an effective analgesia for nerve block over 3 days after single administration, and the analgesic mechanism might be mediated by the regulation of spinal c-FOS expression. However, its potential long-term tissue toxicity needs to be further investigated.

Aplysia Locomotion: Network and Behavioral Actions of GdFFD, a D-Amino Acid-Containing Neuropeptide.

One emerging principle is that neuromodulators, such as neuropeptides, regulate multiple behaviors, particularly motivated behaviors, e.g., feeding and locomotion. However, how neuromodulators act on multiple neural networks to exert their actions remains poorly understood. These actions depend on the chemical form of the peptide, e.g., an alternation of L- to D-form of an amino acid can endow the peptide with bioactivity, as is the case for the Aplysia peptide GdFFD (where dF indicates D-phenylalanine). GdFFD has been shown to act as an extrinsic neuromodulator in the feeding network, while the all L-amino acid form, GFFD, was not bioactive. Given that both GdFFD/GFFD are also present in pedal neurons that mediate locomotion, we sought to determine whether they impact locomotion. We first examined effects of both peptides on isolated ganglia, and monitored fictive programs using the parapedal commissural nerve (PPCN). Indeed, GdFFD was bioactive and GFFD was not. GdFFD increased the frequency with which neural activity was observed in the PPCN. In part, there was an increase in bursting spiking activity that resembled fictive locomotion. Additionally, there was significant activity between bursts. To determine how the peptide-induced activity in the isolated CNS is translated into behavior, we recorded animal movements, and developed a computer program to automatically track the animal and calculate the path of movement and velocity of locomotion. We found that GdFFD significantly reduced locomotion and induced a foot curl. These data suggest that the increase in PPCN activity observed in the isolated CNS during GdFFD application corresponds to a reduction, rather than an increase, in locomotion. In contrast, GFFD had no effect. Thus, our study suggests that GdFFD may act as an intrinsic neuromodulator in the Aplysia locomotor network. More generally, our study indicates that physiological and behavioral analyses should be combined to evaluate peptide actions.