Primary Nerve Research Articles

Using Neural Response Telemetry to Monitor Physiological Responses to Acoustic Stimulation in Hybrid Cochlear Implant Users.

This report describes the results of a series of experiments where we use the neural response telemetry (NRT) system of the Nucleus cochlear implant (CI) to measure the response of the peripheral auditory system to acoustic stimulation in Nucleus Hybrid CI users. The objectives of this study were to determine whether they could separate responses from hair cells and neurons and to evaluate the stability of these measures over time. Forty-four CI users participated. They all had residual acoustic hearing and used a Nucleus Hybrid S8, S12, or L24 CI or the standard lateral wall CI422 implant. The NRT system of the CI was used to trigger an acoustic stimulus (500-Hz tone burst or click), which was presented at a low stimulation rate (10, 15, or 50 per second) to the implanted ear via an insert earphone and to record the cochlear microphonic, the auditory nerve neurophonic and the compound action potential (CAP) from an apical intracochlear electrode. To record acoustically evoked responses, a longer time window than is available with the commercial NRT software is required. This limitation was circumvented by making multiple recordings for each stimulus using different time delays between the onset of stimulation and the onset of averaging. These recordings were then concatenated off-line. Matched recordings elicited using positive and negative polarity stimuli were added off-line to emphasize neural potentials (SUM) and subtracted off-line to emphasize potentials primarily generated by cochlear hair cells (DIF). These assumptions regarding the origin of the SUM and DIF components were tested by comparing the magnitude of these derived responses recorded using various stimulation rates. Magnitudes of the SUM and DIF components were compared with each other and with behavioral thresholds. SUM and DIF components were identified for most subjects, consistent with both hair cell and neural responses to acoustic stimulation. For a subset of the study participants, the DIF components grew as stimulus level was increased, but little or no SUM components were identified. Latency of the CAPs in response to click stimuli was long relative to reports in the literature of recordings obtained using extracochlear electrodes. This difference in response latency and general morphology of the CAPs recorded was likely due to differences across subjects in hearing loss configuration. The use of high stimulation rates tended to decrease SUM and CAP components more than DIF components. We suggest this effect reflects neural adaptation. In some individuals, repeated measures were made over intervals as long as 9 months. Changes over time in DIF, SUM, and CAP thresholds mirrored changes in audiometric threshold for the subjects who experienced loss of acoustic hearing in the implanted ear. The Nucleus NRT software can be used to record peripheral responses to acoustic stimulation at threshold and suprathreshold levels, providing a window into the status of the auditory hair cells and the primary afferent nerve fibers. These acoustically evoked responses are sensitive to changes in hearing status and consequently could be useful in characterizing the specific pathophysiology of the hearing loss experienced by this population of CI users.

RhEPO Enhances Cellular Anti-oxidant Capacity to Protect Long-Term Cultured Aging Primary Nerve Cells

Erythropoietin (EPO) may protect the nervous system of animals against aging damage, making it a potential anti-aging drug for the nervous system. However, experimental evidence from natural aging nerve cell models is lacking, and the efficacy of EPO and underlying mechanism of this effect warrant further study. Thus, the present study used long-term cultured primary nerve cells to successfully mimic the natural aging process of nerve cells. Starting on the 11th day of culture, cells were treated with different concentrations of recombinant human erythropoietin (rhEPO). Using double immunofluorescence labeling, we found that rhEPO significantly improved the morphology of long-term cultured primary nerve cells and increased the total number of long-term cultured primary cells. However, rhEPO did not improve the ratio of nerve cells. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to measure nerve cell activity and showed that rhEPO significantly improved the activity of long-term cultured primary nerve cells. Moreover, Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double immunofluorescence labeling flow cytometry revealed that rhEPO reduced the apoptotic rate of long-term cultured primary nerve cells. Senescence-associated β-galactosidase (SA-β-gal) immunohistochemistry staining showed that rhEPO significantly reduced the aging rate of long-term cultured primary nerve cells. Immunochemistry revealed that rhEPO enhanced intracellular superoxide dismutase (SOD) activity and glutathione (GSH) abundance and reduced the intracellular malondialdehyde (MDA) level. In addition, this effect depended on the dose, was maximized at a dose of 100U/ml and was more pronounced than that of vitamin E. In summary, this study finds that rhEPO protects long-term cultured primary nerve cells from aging in a dose-dependent manner. The mechanism of this effect may be associated with the enhancement of the intracellular anti-oxidant capacity. These findings provide a theoretical basis to further the anti-aging mechanism of EPO in the nervous system, and they provide experimental evidence at the cellular level for the clinical application of EPO to protect the nervous system from aging.

Enterochromaffin Cells Are Gut Chemosensors that Couple to Sensory Neural Pathways

Dietary, microbial, and inflammatory factors modulate the gut-brain axis and influence physiological processes ranging from metabolism to cognition. The gut epithelium is a principal site for detecting such agents, but precisely how it communicates with neural elements is poorly understood. Serotonergic enterochromaffin (EC) cells are proposed to fulfill this role by acting as chemosensors, but understanding how these rare and unique cell types transduce chemosensory information to the nervous system has been hampered by their paucity and inaccessibility to single-cell measurements. Here, we circumvent this limitation by exploiting cultured intestinal organoids together with single-cell measurements to elucidate intrinsic biophysical, pharmacological, and genetic properties of EC cells. We show that EC cells express specific chemosensory receptors, are electrically excitable, and modulate serotonin-sensitive primary afferent nerve fibers via synaptic connections, enabling them to detect and transduce environmental, metabolic, and homeostatic information from the gut directly to the nervous system.

Does the volume of supplemental intraligamentary injections affect the anaesthetic success rate after a failed primary inferior alveolar nerve block? A randomized-double blind clinical trial.

To investigate the efficacy of 0.2mL vs. 0.6mL of 2% lidocaine when given as a supplementary intraligamentary injection after a failed inferior alveolar nerve block (IANB). Ninety-seven adult patients with symptomatic irreversible pulpits received an IANB and root canal treatment was initiated. Pain during treatment was recorded using a visual analogue scale (Heft-Parker VAS). Patients with unsuccessful anaesthesia (n=78) randomly received intraligamentary injection of either 0.2mL or 0.6mL of 2% lidocaine with 1:80000 epinephrine. Root canal treatment was reinitiated. Success after primary injection or supplementary injection was defined as no or mild pain (HP VAS score ≤54mm) during access preparation and root canal instrumentation. Heart rate was monitored using a finger pulse oximeter. The anaesthetic success rates were analysed with Pearson chi-square test at 5% significance levels. The heart rate changes were analysed using t-tests. The intraligamentary injections with 0.2mL solution gave an anaesthetic success rate of 64%, whilst the 0.6mL was successful in 84% of cases with failed primary IANB. (χ2 =4.3, P=0.03). There was no significant effect of the volume of intraligamentary injection on the change in heart rate. Increasing the volume of intraligamentary injection improved the success rates after a failed primary anaesthetic injection.

Upper limb nerve transfers: A review

While upper limb nerve transfers were first described and performed several years ago, they have seen expanded use in the past 20 years. Initially indicated for surgical repair of brachial plexus injuries with nerve root avulsion, the indications have been extended to post-ganglionic lesions because of the excellent results of certain intraplexus nerve transfers. The traditional nerve repair techniques – primary suture and nerve grafting – form the basis of nerve surgery. Although nerve transfer does not replace them, they are a useful supplement as they provide a targeted approach to reinnervation and recovery of key functions of the upper limb. The goal of this review is to provide an overview of the various possible transfers by the function being restored and the quality of the outcomes.

Acute hydrocephalus due to a primary malignant peripheral nerve sheath tumor of the cervicothoracic junction: A case report and review of the literature

BackgroundThe estimated incidence of malignant nerve sheath tumors is 0.001% per year, and only 2–3% of those tumors involve the spinal nerves. We present a rare case of acute hydrocephalus caused by primary malignant peripheral nerve sheath tumor of the cervicothoracic junction. Case descriptionA 29-year-old previously healthy male patient, except for a history of two previous surgeries for ulnar nerve entrapment and progressive left upper extremity weakness, presented with acute onset somnolence. The CT and MRI revealed hydrocephalus and periventricular edema. The patient underwent ventriculoperitoneal shunt surgery. Postoperative MRI of the spine revealed a 6×3×3cm intra-extradural lesion at C7-T1 level and multiple metastases in other spinal segments. The patient underwent combined surgical excision and the tumor was diagnosed as a malignant peripheral nerve sheath tumor based on pathological and immunohistological findings. Radiation therapy and chemotherapy were initiated. ConclusionPrimary malignant peripheral nerve sheath tumor of the spine is a very aggressive tumor with a very high recurrence rate, significant potential for metastasis and very poor overall prognosis. They may present with features of more frequent diseases, such as peripheral neuropathies and may be overlooked as in our case. Thus, suspected cases should undergo a more detailed examination.

Multifocal Motor Neuropathy masquerading as a primary peripheral nerve tumor (P6.131)

Multifocal Motor Neuropathy masquerading as a primary peripheral nerve tumor (P6.131)

Adaptive responses of peripheral lateral line nerve fibres to sinusoidal wave stimuli.

Sensory adaptation is characterized by a reduction in the firing frequency of neurons to prolonged stimulation, also called spike frequency adaptation. This has been documented for sensory neurons of the visual, olfactory, electrosensory, and auditory system both in response to constant-amplitude and to sinusoidal stimuli, but has thus far not been described systematically for the lateral line system. We recorded neuronal activity from primary afferent nerve fibres in the lateral line in goldfish in response to sinusoidal wave stimuli. Depending on stimulus characteristics, afferent fibre responses exhibited a distinct onset followed by a decline in firing rate to an apparent steady-state level, i.e., they exhibited adaptation. The degree of adaptation, measured as the percent decrease in firing rate between onset and steady-state, increased with stimulus amplitude and frequency and with increasing steepness of the rising flank of the stimulus. This may in part be due to the velocity and/or acceleration sensitivity of the lateral line receptors. The time course of the response decline, i.e., the time course of adaptation was best-fit by a power function. This is consistent with the previous studies on spike frequency adaptation in sensory afferents of weakly electric fish.

Outcome of a graduated minimally invasive facial reanimation in patients with facial paralysis.

Peripheral paralysis of the facial nerve is the most frequent of all cranial nerve disorders. Despite advances in facial surgery, the functional and aesthetic reconstruction of a paralyzed face remains a challenge. Graduated minimally invasive facial reanimation is based on a modular principle. According to the patients' needs, precondition, and expectations, the following modules can be performed: temporalis muscle transposition and facelift, nasal valve suspension, endoscopic brow lift, and eyelid reconstruction. Applying a concept of a graduated minimally invasive facial reanimation may help minimize surgical trauma and reduce morbidity. Twenty patients underwent a graduated minimally invasive facial reanimation. A retrospective chart review was performed with a follow-up examination between 1 and 8months after surgery. The FACEgram software was used to calculate pre- and postoperative eyelid closure, the level of brows, nasal, and philtral symmetry as well as oral commissure position at rest and oral commissure excursion with smile. As a patient-oriented outcome parameter, the Glasgow Benefit Inventory questionnaire was applied. There was a statistically significant improvement in the postoperative score of eyelid closure, brow asymmetry, nasal asymmetry, philtral asymmetry as well as oral commissure symmetry at rest (p < 0.05). Smile evaluation revealed no significant change of oral commissure excursion. The mean Glasgow Benefit Inventory score indicated substantial improvement in patients' overall quality of life. If a primary facial nerve repair or microneurovascular tissue transfer cannot be applied, graduated minimally invasive facial reanimation is a promising option to restore facial function and symmetry at rest.

Abstract #812: A Rare Presentation of Coexisting Papillary Thyroid Carcinoma; Primary Hyperparathyroidism and Nerve Sheath Tumors

Abstract #812: A Rare Presentation of Coexisting Papillary Thyroid Carcinoma; Primary Hyperparathyroidism and Nerve Sheath Tumors

Radial nerve palsy in humeral shaft fractures with internal fixation: analysis of management and outcome

IntroductionThe incidence of radial nerve injury after humeral shaft fractures is on average 11.8% (Shao et al., J Bone Jt Surg Br 87(12):1647–1652, 2005) representing the most common peripheral nerve injury associated with long bone fractures (Korompilias et al., Injury, 2013). The purpose of this study was to analyze our current policy and long-term outcome, regarding surgically treated humeral shaft fractures in combination with radial nerve palsy.Materials and methodsWe retrospectively analyzed the data of patients with surgically treated humeral shaft fractures from 01/01/2003 to 28/02/2013. The analysis included fracture type, soft tissue injury regarding closed and open fractures, type of fixation, management, and outcome of radial nerve palsy.ResultsA total of 151 humeral shaft fractures were fixed in our hospital. In 20 (13%) cases, primary radial palsy was observed. Primary nerve exploration was performed in nine cases. Out of the 13 patients with follow-up, 10 showed a complete, 2 a partial, and 1 a minimal nerve recovery. Two of them underwent a revision procedure. Secondary radial nerve palsy occurred in 9 (6%) patients postoperatively. In five patients, the radial nerve was not exposed during the initial surgery and, therefore, underwent revision with nerve exploration. In all 5, a potential cause for the palsy was found and corrected as far as possible with full recovery in 3 and minimal recovery in one patient. In four patients with exposure of the nerve during the initial surgery, no revision was performed. All of these 4 showed a full recovery.ConclusionOur study showed an overall rate of 19% radial nerve palsy in surgically treated humeral shaft fractures. Most of the primary palsies (13%) recovered spontaneously, and therefore, nerve exploration was only exceptionally needed. The incidence of secondary palsy after surgery (6%) was high and mainly seen after plate fixation. In these cases, we recommend early nerve exploration, to detect and treat potential curable neural lesions.

Pattern of Nitrergic Neuronal System Organization in the Brain of Two Holostean Fishes (Actinopterygii: Ginglymodi)

The study of the nitrergic system, formed by the networks of neurons containing the enzyme nitric oxide synthase (NOS), has been extremely useful in unraveling neuroanatomical features of the organization of the central nervous system of vertebrates. Thus, data are available for representatives of most vertebrate classes and, in particular, several studies have detailed the organization of this system in teleosts. In contrast, no information is available regarding this neurotransmission system in the brains of holosteans, an early diverged and poorly understood group of actinopterygian fishes, currently considered a sister group of teleosts that contains only 8 species. The present study provides the first detailed information on the distribution of nitrergic cell bodies and fibers in 2 holostean species of the genus Lepisosteus, the spotted gar L. oculatus and the Florida gar L. platyrhincus. NOS immunohistochemistry and the NADPH diaphorase (NADPH-d) histochemical reaction were used, and both techniques yielded identical results, with the exception of the primary olfactory and terminal nerve fibers, which only labeled for NADPH-d exclusively in L. oculatus. Double immunohistochemistry was conducted for the simultaneous detection of NOS with tyrosine hydroxylase, choline acetyltransferase, calbindin, calretinin, and serotonin to accurately establish the localization of the nitrergic neurons and fibers in the brain of holosteans, the neuroanatomy of which has been mostly neglected, and to assess possible interactions between these neuroactive substances. Distinct groups of nitrergic cells were located in subpallial areas, the basal hypothalamus, posterior tubercle, optic tectum and mesencephalic tegmentum, reticular formation, solitary tract nucleus, spinal cord, and amacrine cells in the retina. In addition, low numbers of nitrergic cells were observed in the pallium, suprachiasmatic nucleus, prethalamic and thalamic areas, torus lateralis and torus semicircularis, cerebellar and laterodorsal tegmental nuclei, and the ventral octavolateral area. Comparison of these results with those from other classes of vertebrates, and including a segmental analysis to correlate cell populations, reveals that the pattern of the nitrergic system in holosteans is very close to that in ancestral actinopterygian fishes and highlights conserved and derived traits.

Afferent Fiber Remodeling in the Somatosensory Thalamus of Mice as a Neural Basis of Somatotopic Reorganization in the Brain and Ectopic Mechanical Hypersensitivity after Peripheral Sensory Nerve Injury.

Plastic changes in the CNS in response to peripheral sensory nerve injury are a series of complex processes, ranging from local circuit remodeling to somatotopic reorganization. However, the link between circuit remodeling and somatotopic reorganization remains unclear. We have previously reported that transection of the primary whisker sensory nerve causes the abnormal rewiring of lemniscal fibers (sensory afferents) on a neuron in the mouse whisker sensory thalamus (V2 VPM). In the present study, using transgenic mice whose lemniscal fibers originate from the whisker sensory principle trigeminal nucleus (PrV2) are specifically labeled, we identified that the transection induced retraction of PrV2-originating lemniscal fibers and invasion of those not originating from PrV2 in the V2 VPM. This anatomical remodeling with somatotopic reorganization was highly correlated with the rewiring of lemniscal fibers. Origins of the non-PrV2-origin lemniscal fibers in the V2 VPM included the mandibular subregion of trigeminal nuclei and the dorsal column nuclei (DCNs), which normally represent body parts other than whiskers. The transection also resulted in ectopic receptive fields of V2 VPM neurons and extraterritorial pain behavior on the uninjured mandibular region of the face. The anatomical remodeling, emergence of ectopic receptive fields, and extraterritorial pain behavior all concomitantly developed within a week and lasted more than three months after the transection. Our findings, thus, indicate a strong linkage between these plastic changes after peripheral sensory nerve injury, which may provide a neural circuit basis underlying large-scale reorganization of somatotopic representation and abnormal ectopic sensations.

Effects of sensory and motor nerve homogenates at different concentrations on proliferation and osteogenesis differentiation of bone marrow mesenchymal stem cells

Objective To investigate the effect of sensory and motor nerve homogenates at different concentrations on the proliferation and osteogenesis differentiation of bone marrow mesenchymal stem cells (BMSCs) in rats. Methods The saphenous nerve and the muscle branch of the sciatic nerve in rats were extracted surgically as sensory and motor nerve tissues, respectively. The primary nerve homogenates(10 mg/mL) were prepared as per 10 mg tissue with 1 mL osteoblast inducing conditional media, and 10 times diluted after filtration purification to prepare sensory and motor nerve homogenates at concentration gradients of 1.0, 0.1, 0.01, 0.001 and 0.0001 mg/mL. Cultivation GFP+ rat pups BMSCs in vitro were trained to P3 generation. The experiment was carried out in 3 groups. The sensory and motor nerve homogenates of 500 μL at the above 6 concentration gradients were added during cultivation respectively in the sensory nerve group (n=18) and the motor nerve group(n=18) while 500 μL of osteoblast inducing conditional media was added in the control group(n=3). Cell proliferation quantity detection and alkaline phosphatase (ALP) staining were used to assess the proliferation and differentiation of BMSCs after 14 days. Results According to the results of CCK-8, the cellular absorbance values at concentrations of 1.0 and 0.1 mg/mL homogenate in the sensory nerve group (1.957±0.065 and 1.751±0.073) were significantly greater than in the control group (1.145±0.087) while the cellular absorbance value at concentration of 10.0 mg/mL homogenate in the motor nerve group(0.304±0.619) was significantly smaller than in the control group (1.145±0.087) (P< 0.05). According to the ALP staining, the amounts of cellular calcium nodules in the sensory and motor nerve groups (2.667±0.816 and 3.000±0.632, respectively) were significantly smaller than in the control group (11.833±1.471) (P< 0.05). Conclusion Sensory nerve homogenate is different from motor nerve homogenate in that it may promote proliferation of BMSCs and inhibit osteogenesis differentiation of BMSCs in a certain rage of concentrations. Key words: Nerve; Bone marrow cells; Mesenchymal stem cells; Cell proliferation; Cell differentiation

Fibrin Glue Increases the Tensile Strength of Conduit-Assisted Primary Digital Nerve Repair.

An ideal peripheral nerve repair construct does not currently exist. Our primary goal was to determine whether fibrin glue adds to the tensile strength of conduit-assisted primary digital nerve repairs. Our secondary goal was to evaluate the impact of varying suture number and location on the tensile strength. Ninety cadaveric digital nerves were harvested and divided equally into the following repair groups: A (4/4), B (2/2), C (0/2), D (0/1), and E (0/0) with the first number referring to the number of sutures at the coaptation and the second number referring to the number of sutures at each proximal and distal end of the nerve-conduit junction. When fibrin glue was added, the group was labeled prime. The nerve specimens were transected and then repaired with 8-0 nylon suture and conduit. The tensile strength of the repairs was tested, and maximum failure load was determined. The results were analyzed with a 2-way analysis of variance. The Tukey post hoc test compared repair groups if the 2-way analysis of variance showed significance. Both suture group and glue presence significantly affected the maximum failure load. Increasing the number of sutures increased the maximum failure load, and the presence of fibrin glue also increased the failure load. Fibrin glue was found to increase the strength of conduit-assisted primary digital nerve repairs. Furthermore, the number of sutures correlated to the strength of the repair. Fibrin glue may be added to a conduit-assisted primary digital nerve repair to maintain strength and allow fewer sutures at the primary coaptation site.

Phosphorylated Histone 3 at Serine 10 Identifies Activated Spinal Neurons and Contributes to the Development of Tissue Injury-Associated Pain

Transcriptional changes in superficial spinal dorsal horn neurons (SSDHN) are essential in the development and maintenance of prolonged pain. Epigenetic mechanisms including post-translational modifications in histones are pivotal in regulating transcription. Here, we report that phosphorylation of serine 10 (S10) in histone 3 (H3) specifically occurs in a group of rat SSDHN following the activation of nociceptive primary sensory neurons by burn injury, capsaicin application or sustained electrical activation of nociceptive primary sensory nerve fibres. In contrast, brief thermal or mechanical nociceptive stimuli, which fail to induce tissue injury or inflammation, do not produce the same effect. Blocking N-methyl-D-aspartate receptors or activation of extracellular signal-regulated kinases 1 and 2, or blocking or deleting the mitogen- and stress-activated kinases 1 and 2 (MSK1/2), which phosphorylate S10 in H3, inhibit up-regulation in phosphorylated S10 in H3 (p-S10H3) as well as fos transcription, a down-stream effect of p-S10H3. Deleting MSK1/2 also inhibits the development of carrageenan-induced inflammatory heat hyperalgesia in mice. We propose that p-S10H3 is a novel marker for nociceptive processing in SSDHN with high relevance to transcriptional changes and the development of prolonged pain.

Malignant primary nerve sheath tumor of the cauda equina in a patient without Von Recklinghausen disease

Malignant peripheral nerve sheath tumor (MPNST) is a rare variety of soft-tissue sarcoma of ecto-mesenchymal origin. Various sites have been mentioned, but it is rare in cauda equina. Only five cases of MPNST of cauda equina are reported till date. A 42-year-old male presented with complaints of weakness in lower limbs for last 5 months with bladder and bowel dysfunction. On magnetic resonance imaging, an isointense lesion on T1 and a hyperintense on T2 imaging was found at terminal spinal cord level. The lesion was excised following laminectomy and showed varied cellularity with thin oval, polyhedral and spindle-shaped cells arranged in bundles on microscopic examination suggesting MPNST. MPNST of cauda equina is rare and is associated with Neurofibromatosis Type-1 or radiation exposure, but is rarer without these risk factors. Prognosis is favorable in these cases.

Pathogenesis of abdominal pain in bowel obstruction: role of mechanical stress-induced upregulation of nerve growth factor in gut smooth muscle cells.

Abdominal pain is one of the major symptoms in bowel obstruction (BO); its cellular mechanisms remain incompletely understood. We tested the hypothesis that mechanical stress in obstruction upregulates expression of nociception mediator nerve growth factor (NGF) in gut smooth muscle cells (SMCs), and NGF sensitizes primary sensory nerve to contribute to pain in BO. Partial colon obstruction was induced with a silicon band implanted in the distal bowel of Sprague-Dawley rats. Colon-projecting sensory neurons in the dorsal root ganglia (T13 to L2) were identified for patch-clamp and gene expression studies. Referred visceral sensitivity was assessed by measuring withdrawal response to stimulation by von Frey filaments in the lower abdomen. Membrane excitability of colon-projecting dorsal root ganglia neurons was significantly enhanced, and the withdrawal response to von Frey filament stimulation markedly increased in BO rats. The expression of NGF mRNA and protein was increased in a time-dependent manner (day 1-day 7) in colonic SMC but not in mucosa/submucosa of the obstructed colon. Mechanical stretch in vitro caused robust NGF mRNA and protein expression in colonic SMC. Treatment with anti-NGF antibody attenuated colon neuron hyperexcitability and referred hypersensitivity in BO rats. Obstruction led to significant increases of tetrodotoxin-resistant Na currents and mRNA expression of Nav1.8 but not Nav1.6 and Nav1.7 in colon neurons; these changes were abolished by anti-NGF treatment. In conclusion, mechanical stress-induced upregulation of NGF in colon SMC underlies the visceral hypersensitivity in BO through increased gene expression and activity of tetrodotoxin-resistant Na channels in sensory neurons.

Somatostatin Receptor SPECT/CT using 99mTc Labeled HYNIC-TOC Aids in Diagnosis of Primary Optic Nerve Sheath Meningioma.

Primary optic nerve sheath meningiomas (ONSM) are rare, benign and slow growing tumor involving the intra-orbital/intra-canalicular segment of the optic nerve. Untreated, they can potentially lead to visual deterioration. Magnetic resonance (MR) is the gold standard imaging modality for diagnosing the entity. Often, a clinical dilemma exists to narrow the differential diagnosis of an enhancing intra-orbital mass on MR. Molecular imaging provides a high degree of precision in diagnosing meningioma in view of relatively high levels of somatostatin receptor expression by these tumors. The following case demonstrates the potential clinical utility of somatostatin receptor SPECT using 99mTc- labeled HYNIC-TOC in clinical diagnosis of ONSM.

A Potential Role of Chronic Exposure to Extremely Low-Frequency Electromagnetic Fields in Triggering Persistent Pain Post Breast Cancer Surgery: A Review

Persistent Pain after Breast Cancer Surgery (PPBCS) ranks second to amputation of extremities for neuropathic chronic pain. PPBCS is associated with the formation of intercostobrachial neuroma bulbs along the lateral chest. These neuroma bulbs are either un-/thinly myelinated and express hypersensitivity to environmental stimuli. Hypersensitivity is manifested as spontaneous pain in response to innocuous stimuli and exaggerating pain in response to noxious stimuli. Excision of neuromas, a common intervention to alleviate pain, has been reported as ineffective. Experience of individuals with amputation of extremities and experimental models of human nerve injuries confirm anthropogenic EMF evoke excruciating pain. Findings from invitro and animal studies clearly support that EMF exposure depolarizes cell membranes, interrupts voltage gated calcium channels which then activates peripheral sensory neurons and initiates propagation of a train of action potentials along the axons of primary afferent nerve fibers. The World Health Organization guidelines, established based on approximation of the human anatomy are limited and assumes no potential compounding effects of nerve injuries or alterations of physiological milieu of tissues. The objective of this review is to direct the attention of the medical community to the potential role of anthropogenic EMF as a risk factor for persistent pain after breast surgery. Patients rely heavily on the recommendations of their providers to manage their pain. The current epidemic of opioid abuse in the US has been partially attributed to the high prescription rate of opioid-based pain killers. Understanding the potential triggers of chronic pain can reduce dependency on pharmaceutical agents.