Dermal macrophages set pain sensitivity by modulating the amount of tissue NGF through an SNX25-Nrf2 pathway.

Cross-talk between peripheral neurons and immune cells is important in pain sensation. We identified Snx25 as a pain-modulating gene in a transgenic mouse line with reduced pain sensitivity. Conditional deletion of Snx25 in monocytes and macrophages, but not in peripheral sensory neurons, in mice (Snx25cKO mice) reduced pain responses in both normal and neuropathic conditions. Bone marrow transplantation using Snx25cKO and wild-type mice indicated that macrophages modulated pain sensitivity. Expression of sorting nexin (SNX)25 in dermal macrophages enhanced expression of the neurotrophic factor NGF through the inhibition of ubiquitin-mediated degradation of Nrf2, a transcription factor that activates transcription of Ngf. As such, dermal macrophages set the threshold for pain sensitivity through the production and secretion of NGF into the dermis, and they may cooperate with dorsal root ganglion macrophages in pain perception.

Large-scale electron microscopic volume imaging of interfascicular oligodendrocytes in the mouse corpus callosum.

Single oligodendrocytes produce myelin sheaths around multiple axons in the central nervous system. Interfascicular oligodendrocytes (IOs) facilitate nerve conduction, but their detailed morphologies remain largely unknown. In the present study, we three-dimensionally reconstructed IOs in the corpus callosum of adult mouse using serial block face scanning electron microscopy. The cell bodies of IOs were morphologically polarized and extended thick processes from the cytoplasm-rich part of the cell. Processes originating from the cell body of each IO can be classified into two types: one myelinates an axon without branching, while the other type branches and each branch myelinates a distinct axon. Myelin sheaths originating from a particular IO have biased thicknesses, wrapping axons of a limited range of diameters. Consistent with this finding, IOs transduced and visualized with a rabies viral vector expressing GFP showed statistically significant variation in their myelination patterns. We further reconstructed the sheath immediately adjacent to that derived from each of the analyzed IOs; the thicknesses of the pair of sheaths were significantly correlated despite emanating from different IOs. These results suggest that a single axon could regulate myelin sheath thicknesses, even if the sheaths are derived from distinct IOs. Collectively, our results indicate that the IOs have their own myelin profiles defined by myelin thickness and axonal diameter although axons may regulate thickness of myelin sheath.

Intraoperative feasibility of bulbocavernosus reflex monitoring during untethering surgery in infants and children.

Bulbocavernosus reflex (BCR) monitoring is used to assess the integrity of urinary and bowel function. In this study, we evaluated the feasibility of BCR monitoring during untethering surgery in infants and children to predict postoperative urinary and bowel dysfunction. The records of 22 patients ranging from 4 days to 10 years old (mean 2.7 ± 3.3 years) were reviewed. Anesthesia was maintained by propofol or sevoflurane/opioid without neuromuscular blockade. BCR waveforms induced by electrical stimulation (20-40 mA, train-of-four pulses with 500 Hz) to the penis or clitoris were recorded from bilateral external anal sphincters. To assess the sensitivity and specificity of BCR monitoring, we investigated the association between a significant continuous decrease in BCR amplitude at the end of surgery and postoperative urinary and bowel dysfunction after surgery. Reproducible baseline BCR waveforms were successfully recorded in 20 of 22 patients (90.9%). A significant continuous decrease in BCR amplitude was observed in 8 patients. The results of intraoperative BCR monitoring included three true-positives, twelve true-negatives, five false-positives, and zero false-negatives. Therefore, the sensitivity and specificity of BCR monitoring used to predict postoperative urinary and bowel dysfunction were 100 and 70.6%, respectively. BCR monitoring during untethering surgery in infants and children under general anesthesia was found to be a feasible method to prevent postoperative urinary and bowel dysfunction.

Hedgehog Signaling Modulates the Release of Gliotransmitters from Cultured Cerebellar Astrocytes.

Sonic hedgehog (Shh), a member of the Hedgehog (Hh) family, plays essential roles in the development of the central nervous system. Recent studies suggest that the Hh signaling pathway also functions in mature astrocytes under physiological conditions. We first examined the expression of genes encoding Hh signaling molecules in the adult mouse cerebellum by in situ hybridization histochemistry. mRNA for Patched homolog 1 (Ptch1), a receptor for Hh family members, was expressed in S100ß-positive astrocytes and Shh mRNA was expressed in HuC/D-positive neurons, implying that the Hh signaling pathway contributes to neuro-glial interactions. To test this hypothesis, we next examined the effects of recombinant SHH N-terminal protein (rSHH-N) on the functions of cultured cerebellar astrocytes. rSHH-N up-regulated Hh signal target genes such as Ptch1 and Gli-1, a key transcription factor of the Hh signaling pathway. Although activation of Hh signaling by rSHH-N or purmorphamine influenced neither glutamate uptake nor gliotransmitters release, inhibition of the Hh signaling pathway by cyclopamine, neutralizing antibody against SHH or intracellular Ca(2+) chelation decreased glutamate and ATP release from cultured cerebellar astrocytes. On the other hand, cyclopamine, neutralizing antibody against SHH or Ca(2+) chelator hardly affected D-serine secretion. Various kinase inhibitors attenuated glutamate and ATP release, while only U0126 reduced D-serine secretion from the astrocytes. These results suggested that the Hh signaling pathway sustains the release of glutamate and ATP and participates in neuro-glial interactions in the adult mouse brain. We also propose that signaling pathways distinct from the Hh pathway govern D-serine secretion from adult cerebellar astrocytes.

Two cases in which the effectiveness of "laryngospasm notch" pressure against laryngospasm was confirmed by imaging examinations.

We report two cases in which development of laryngospasm and release of the spasm immediately after applying pressure in the "laryngospasm notch" was confirmed by ultrasonographic and fiberoptic examinations. A bronchoscopy was planned under propofol sedation using a laryngeal mask airway for a 61-year-old man after subtotal esophagotomy. When a bronchoscope was advanced into the trachea, the vocal cords suddenly closed. Immediately after pressure with the fingertips was applied to the "laryngospasm notch," the vocal cords opened, which was observed through the bronchoscope in real time. A 22-year-old woman presented for emergency caesarean section under general anesthesia. After the completion of the procedures, the patient was not yet following commands but her breathing was steady. Thus, extubation was performed; however, she began to display signs of respiratory stridor. An ultrasonographic examination revealed that the vocal cords were noted to close, which suggested that she was developing laryngospasm. With this diagnosis, pressure at the "laryngospasm notch" was applied. Immediately after this maneuver, the vocal cords opened. We reconfirmed that applying pressure in the "laryngospasm notch" was effective to release laryngospasm. Imaging studies, especially ultrasonographic examination, were useful for making the decision to apply pressure in the "laryngospasm notch."

[Perioperative management of tongue reduction surgery for macroglossia associated with Beckwith-Wiedemann syndrome -A retrospective evaluation of 14 patients--].

BACKGROUND: Macroglossia is the commonest symptom of Beckwith-Wiedemann syndrome (BWS) and sometimes requires surgical tongue reduction for cosmetic, feeding, drooling and speech problems. METHODS: We retrospectively reviewed the perioperative course of 14 BWS patients. The subjects were children who underwent tongue reduction surgery or glossopexy between 1994 and 2008 at Osaka Medical Center for Maternal & Child Health. RESULTS: The median age was 18 months, and the median weight was 12.2 kg at the time of surgery. One patient had the trachea intubated and another had tracheostomy to keep airway patency. Other 12 patients had no artificial airway and were premedicated with midazolam or diazepam and had the trachea intubated after induction with sevoflurane and nitrous oxide in oxygen. Only one patient developed difficult mask ventilation for which a nasal airway was applied. No patients demonstrated difficult intubation. All without preoperative artificial airway were extubated in the OR after the surgery. One patient demonstrated hypoglycemia. Airway compromise in the two patients who was intubated or had tracheostomy prior to surgery was not alleviated by the surgery. CONCLUSIONS: Airway disorder was not alleviated by tongue reduction surgery or glossopexy.

Transurethral electrical stimulation for intraoperative bulbocavernosus reflex monitoring during spine surgery in females.

OBJECTIVE: Intraoperative bulbocavernosus reflex (BCR) monitoring is more difficult in females than in males. This study was designed to compare the feasibility of transurethral electrical stimulation BCR (tu-BCR) monitoring with that of conventional BCR (c-BCR) monitoring during spine surgery in females. METHODS: Twenty-four females were included. For stimulation in c-BCR monitoring, a pair of surface electrodes was placed on the genitals (cathode/anode: clitoris/adjacent labium). For stimulation in tu-BCR monitoring, a urethral catheter attached to a pair of electrodes was inserted into the urethra. BCRs were recorded from the external anal sphincter after a single train of four stimulation pulses. RESULTS: There was no postoperative urinary tract injury associated with urethral catheter insertion for tu-BCR. Tu-BCR monitoring had a significantly higher success rate of baseline recording than c-BCR monitoring (87.5% vs 66.7%, respectively, p = 0.028). The specificities of tu-BCR and c-BCR monitoring were 100% and 87.2%, respectively. The sensitivity was not calculated because no patients had postoperative urinary or bowel dysfunction. CONCLUSIONS: Our data indicate that tu-BCR monitoring improved the success rate of baseline recording and specificity during spine surgery in females. SIGNIFICANCE: Tu-BCR monitoring was more reliable than c-BCR monitoring during spine surgery in females.

Amino acid infusions started after development of intraoperative core hypothermia do not affect rewarming but reduce the incidence of postoperative shivering during major abdominal surgery: a randomized trial.

PURPOSE: Previous studies have demonstrated that amino acid infusions exert enhanced thermogenic effects during general anesthesia. This study was conducted to investigate whether amino acid infusions started after development of intraoperative core hypothermia can accelerate rewarming. METHODS: Twenty-two patients scheduled for major abdominal surgery were included in this study. When tympanic temperature reached 35.5°C, patients were randomly assigned to receive amino acids (amino acid group; n = 11) or saline (saline group; n = 11). A continuous infusion of a mixture of 18 amino acids or saline was started at 200 ml h(-1). Tympanic, forearm, and digit temperatures were recorded. Forearm minus fingertip skin-surface temperature gradients (temperature gradient) were calculated. Postoperative shivering was also evaluated. RESULTS: Tympanic membrane temperature and temperature gradient were similar between the two groups at each time point during the study period. Temperature gradient at extubation in the amino acid group was significantly lower than in the saline group although tympanic temperature at extubation was similar between the two groups. Postoperative shivering score was significantly lower in the amino acid group than in the saline group. CONCLUSIONS: Amino acid infusions started after development of intraoperative core hypothermia failed to accelerate rewarming. However, amino acid infusions reduced the incidence of postoperative shivering. Use of amino acid infusions to reduce thermoregulatory vasoconstriction at emergence might contribute to a decrease in the development of postoperative shivering.

[Use of landiolol hydrochloride for the prevention of atrial fibrillation after lung resection].

BACKGROUND: We examined the effect of landiolol hydrochloride, a selective beta1-adrenoreceptor antagonist, on the incidence of atrial fibrillation(AF). METHODS: The incidence of AF after lung resection was evaluated retrospectively in patients with intraoperative treatment with landiolol hydrochloride or those without it. Landiolol hydrochloride (5 microg x kg(-1) x min(-1)) was administered intravenously from the beginning of anesthesia induction to the end of operation. RESULTS: In non-treatment group with landiolol hydrochloride (224 patients), the incidence of AF after surgery was 14.2%, peaking on postoperative day 2, and the average peak day was day 3.5. Older age, removal of the lymph nodes, lengthy surgery, and ischemic heart failure were risk factors. In treatment group with landiolol hydrochloride (77 patients), the incidence of AF after surgery was 5.2%, which was significantly lower than that in non-treatment group. Increased numbers of risk factors led to the high incidence of AF. But the administration of landiolol hydrochloride suppressed the incidence of AF. CONCLUSIONS: Landiolol hydrochloride is effective for the preventionof AF and it is safe without causing a severe decrease in blood pressure and bradycardia in high risk patients.

NGF and BDNF expression in mouse DRG after spared nerve injury.

Neuropathic pain is initiated by a primary lesion in the peripheral nervous system and spoils quality of life. Neurotrophins play important roles in the development and transmission of neuropathic pain. There are conflicting reports that the dorsal root ganglion (DRG) in an injured nerve contribute to neuropathic pain, whereas several studies have highlighted the important contribution of the DRG in a non-injured nerve. Clarifying the role of neurotrophins in neuropathic pain is problematic because we cannot distinguish injured and intact neurons in most peripheral nerve injury models. In the present study, to elicit neuropathic pain, we used the spared nerve injury (SNI) model, in which injured DRG neurons are distinguishable from intact ones, and mechanical allodynia develops in the intact sural nerve skin territory. We examined nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) expression in the DRGs of SNI model mice. NGF and BDNF levels increased in the injured L3 DRG, while NGF decreased in the intact L5 DRG. These data offer a new point of view on the role of these neurotrophins in neuropathic pain induced by peripheral nerve injury.

Propofol induces nuclear localization of Nrf2 under conditions of oxidative stress in cardiac H9c2 cells.

Oxidative stress contributes to myocardial ischemia-reperfusion injury, which causes cardiomyocyte death and precipitate life-threatening heart failure. Propofol has been proposed to protect cells or tissues against oxidative stress. However, the mechanisms underlying its beneficial effects are not fully elucidated. In the present study, we employed an in vitro oxidative injury model, in which rat cardiac H9c2 cells were treated with H2O2, and investigated roles of propofol against oxidative stress. Propofol treatment reduced H2O2-induced apoptotic cell death. While H2O2 induced expression of the antioxidant enzyme HO-1, propofol further increased HO-1 mRNA and protein levels. Propofol also promoted nuclear localization of Nrf2 in the presence of H2O2. Knockdown of Nrf2 using siRNA suppressed propofol-inducible Nrf2 and expression of Nrf2-downstream antioxidant enzyme. Knockdown of Nrf2 suppressed the propofol-induced cytoprotection. In addition, Nrf2 overexpression induced nuclear localization of Nrf2 and HO-1 expression. These results suggest that propofol exerts antioxidative effects by inducing nuclear localization of Nrf2 and expression of its downstream enzyme in cardiac cells. Finally, we examined the effect of propofol on cardiomyocytes using myocardial ischemia-reperfusion injury models. The expression level of Nrf2 protein was increased at 15 min after reperfusion in the ischemia-reperfusion and propofol group compared with ischemia-reperfusion group in penumbra region. These results suggest that propofol protects cells or tissues from oxidative stress via Nrf2/HO-1 cascade.

Olig2-Lineage Astrocytes: A Distinct Subtype of Astrocytes That Differs from GFAP Astrocytes.

Astrocytes are the most abundant glia cell type in the central nervous system (CNS), and are known to constitute heterogeneous populations that differ in their morphology, gene expression and function. Although glial fibrillary acidic protein (GFAP) is the cardinal cytological marker of CNS astrocytes, GFAP-negative astrocytes can easily be found in the adult CNS. Astrocytes are also allocated to spatially distinct regional domains during development. This regional heterogeneity suggests that they help to coordinate post-natal neural circuit formation and thereby to regulate eventual neuronal activity. Here, during lineage-tracing studies of cells expressing Olig2 using Olig2CreER; Rosa-CAG-LSL-eNpHR3.0-EYFP transgenic mice, we found Olig2-lineage mature astrocytes in the adult forebrain. Long-term administration of tamoxifen resulted in sufficient recombinant induction, and Olig2-lineage cells were found to be preferentially clustered in some adult brain nuclei. We then made distribution map of Olig2-lineage astrocytes in the adult mouse brain, and further compared the map with the distribution of GFAP-positive astrocytes visualized in GFAPCre; Rosa-CAG-LSL-eNpHR3.0-EYFP mice. Brain regions rich in Olig2-lineage astrocytes (e.g., basal forebrain, thalamic nuclei, and deep cerebellar nuclei) tended to lack GFAP-positive astrocytes, and vice versa. Even within a single brain nucleus, Olig2-lineage astrocytes and GFAP astrocytes frequently occupied mutually exclusive territories. These findings strongly suggest that there is a subpopulation of astrocytes (Olig2-lineage astrocytes) in the adult brain, and that it differs from GFAP-positive astrocytes in its distribution pattern and perhaps also in its function. Interestingly, the brain nuclei rich in Olig2-lineage astrocytes strongly expressed GABA-transporter 3 in astrocytes and vesicular GABA transporter in neurons, suggesting that Olig2-lineage astrocytes are involved in inhibitory neuronal transmission.

Voluntary Exercise Induces Astrocytic Structural Plasticity in the Globus Pallidus.

Changes in astrocyte morphology are primarily attributed to the fine processes where intimate connections with neurons form the tripartite synapse and participate in neurotransmission. Recent evidence has shown that neurotransmission induces dynamic synaptic remodeling, suggesting that astrocytic fine processes may adapt their morphologies to the activity in their environment. To illustrate such a neuron-glia relationship in morphological detail, we employed a double transgenic Olig2(CreER/WT); ROSA26-GAP43-EGFP mice, in which Olig2-lineage cells can be visualized and traced with membrane-targeted GFP. Although Olig2-lineage cells in the adult brain usually become mature oligodendrocytes or oligodendrocyte precursor cells with NG2-proteoglycan expression, we found a population of Olig2-lineage astrocytes with bushy morphology in several brain regions. The globus pallidus (GP) preferentially contains Olig2-lineage astrocytes. Since the GP exerts pivotal motor functions in the indirect pathway of the basal ganglionic circuit, we subjected the double transgenic mice to voluntary wheel running to activate the GP and examined morphological changes of Olig2-lineage astrocytes at both the light and electron microscopic levels. The double transgenic mice were divided into three groups: control group mice were kept in a cage with a locked running wheel for 3 weeks, Runner group were allowed free access to a running wheel for 3 weeks, and the Runner-Rest group took a sedentary 3-week rest after a 3-week running period. GFP immunofluorescence analysis and immunoelectron microscopy revealed that astrocytic fine processes elaborated complex arborization in the Runner mice, and reverted to simple morphology comparable to that of the Control group in the Runner-Rest group. Our results indicated that the fine processes of the Olig2-lineage astrocytes underwent plastic changes that correlated with overall running activities, suggesting that they actively participate in motor functions.

[A case of deep vein thrombosis in spite of using an intermittent pneumatic compression device].

A 69-year-old male patient underwent subtotal esophagectomy for esophageal cancer under sevoflurane anesthesia combined with epidural analgesia. According to the protocol for the prevention of deep vein thrombosis (DVT) in our hospital, only an intermittent pneumatic compression device (IPC) and elastic stockings were perioperatively used for prophylaxis of DVT although D-dimer level was slightly increased to 1.2 microg x ml(-1). On the 2nd post-operative day, a venous ultrasound examination was performed, because D-dimer level was suddenly increased up to 41.5 microg x ml(-1) without any signs of thrombus in the atrium and pleural cavity. Since DVT was detected with the right lower limb, the use of an IPC was stopped and an inferior vena cava filter was inserted through the right jugular vein with a continuous administration of heparin. An aggressive search should be performed if DVT is suspected by any clinical signs including an increase in D-dimer level. We should also keep in mind the possibility of DVT even if an IPC and elastic stockings are perioperatively used.

Pulmonary hypertension due to unknown causes in liver resection.

A 16-year-old male underwent transcatheter arterial embolization against a large hepatic tumor, and was subsequently scheduled for removal of the tumor. Sudden hypotension and tachycardia were observed on removal of the tumor. Massive bleeding or obstruction of the inferior vena cava was expected to develop, but this did not occur because of simultaneous pulmonary hypertension (PH). The development of acute PH due to pulmonary vasoconstriction was suspected. Milrinone and prostaglandin E1 were effective. The same type of PH was again observed during manipulation of the residual portion of the liver. The acute PH was reproducible each time the liver was manipulated, which could suggest that this series of PH was specifically related to the hepatic lesion. A necrotic hepatic lesion might play an important role in disturbing the pulmonary circulation and causing the development of acute PH.