Selective neural inhibition via photobiomodulation alleviates behavioral hypersensitivity associated with small sensory fiber activation.

OBJECTIVE: Photobiomodulation at higher irradiances has great potential as a pain-alleviating method that selectively inhibits small diameter nerve fibers and corresponding sensory experiences, such as nociception and heat sensation. The longevity and magnitude of these effects as a function of laser irradiation parameters at the nerve was explored. METHODS: In a rodent chronic pain model (spared nerve injury-SNI), light was applied directly at the sural nerve with four delivery schemes: two irradiance levels (7.64 and 2.55 W/cm2 ) for two durations each, corresponding to either 4.8 or 14.4 J total energy, and the effect on sensory hypersensitivities was evaluated. RESULTS: At emitter irradiances of 7.64 W/cm2 (for 240 s), 2.55 W/cm2 (for 720 s), and 7.64 W/cm2 (for 80 s) the heat hypersensitivity was relieved the day following photobiomodulation (PBM) treatment by 37 ± 8.1% (statistically significant, p < 0.001), 26% ± 6% (p = 0.072), and 28 ± 6.1% (statistically significant, p = 0.032), respectively, and all three treatments reduced the hypersensitivity over the course of the experiment (13 days) at a statistically significant level (mixed-design analysis of variance, p < 0.05). The increases in tissue temperature (5.3 ± 1.0 and 1.3 ± 0.4°C from 33.3°C for the higher and lower power densities, respectively) at the neural target were well below those typically associated with permanent action potential disruption. CONCLUSIONS: The data from this study support the use of direct PBM on nerves of interest to reduce sensitivities associated with small-diameter fiber activity.

Soft ferroelectret ultrasound receiver for targeted peripheral neuromodulation.

Bioelectronic medicine is a rapidly growing field where targeted electrical signals can act as an adjunct or alternative to drugs to treat neurological disorders and diseases via stimulating the peripheral nervous system on demand. However, current existing strategies are limited by external battery requirements, and the injury and inflammation caused by the mechanical mismatch between rigid electrodes and soft nerves. Here we report a wireless, leadless, and battery-free ferroelectret implant, termed NeuroRing, that wraps around the target peripheral nerve and demonstrates high mechanical conformability to dynamic motion nerve tissue. As-fabricated NeuroRing can act as an ultrasound receiver that converts ultrasound vibrations into electrostimulation pulses, thus stimulating the targeted peripheral nerve on demand. This capability is demonstrated by the precise modulation of the sacral splanchnic nerve to treat colitis, providing a framework for future bioelectronic medicines that offer an alternative to non-specific pharmacological approaches.

Intraoperative Electromyography in Awake Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Case Study on Nerve Activation Under the Effects of Local Anesthesia.

SUMMARY: With the versatility of lumbar spine surgery continually expanding, intraoperative electromyography (EMG) has become a common adjunct used to reduce risk of nerve injury and postoperative neurologic deficit. EMG monitoring has been deemed particularly useful in the minimally invasive transforaminal lumbar interbody fusion. A more recent evolution of the minimally invasive transforaminal lumbar interbody fusion entails complete percutaneous access to the disc through Kambin's triangle, followed by a percutaneous lumbar interbody fusion. Given the lack of direct visualization of nervous structures with percutaneous entrance into the disc, there is risk of injury to surrounding nervous structures with this approach. In effort to reduce risk of nerve injury, application of triggered EMG to gauge proximity of nervous tissue has been evaluated. Recently, patients presenting with contraindications or concerns for general anesthesia have been offered the alternative to undergo their procedure with spinal anesthesia, allowing them to remain awake. Spinal anesthesia entails intrathecal administration of local anesthetic, which mechanistically acts to reduce overall excitability of surrounding neural structures. However, nerve activation under conditions of local anesthetic is relatively unknown, and the ability of triggered EMG monitoring to reliably detect nerve proximity becomes questionable. This case report demonstrates nerve activation at thresholds comparable with those seen under general anesthesia. Although this has sparked interest in the possibility that local anesthetic may not remarkably affect nerve excitability as measured by triggered EMG activation, further investigation is recommended to reliably apply triggered EMG monitoring in awake spine surgery.

Electrochemical modulation enhances the selectivity of peripheral neurostimulation in vivo.

Electrical nerve stimulation serves an expanding list of clinical applications, but it faces persistent challenges in selectively activating bundled nerve fibers. In this study, we investigated electrochemical modulation with an ion-selective membrane (ISM) and whether it, used together with electrical stimulation, may provide an approach for selective control of peripheral nerves. Guided by theoretical transport modeling and direct concentration measurements, we developed an implantable, multimodal ISM cuff capable of simultaneous electrical stimulation and focused Ca2+ depletion. Acutely implanting it on the sciatic nerve of a rat in vivo, we demonstrated that Ca2+ depletion could increase the sensitivity of the nerve to electrical stimulation. Furthermore, we found evidence that the effect of ion modulation would selectively influence functional components of the nerve, allowing selective activation by electrical current. Our results raise possibilities for improving functional selectivity of new and existing bioelectronic therapies, such as vagus nerve stimulation.

Photodynamic Activity of Protoporphyrin IX-Immobilized Cellulose Monolith for Nerve Tissue Regeneration.

The development of nerve conduits with a three-dimensional porous structure has attracted great attention as they closely mimic the major features of the natural extracellular matrix of the nerve tissue. As low levels of reactive oxygen species (ROS) function as signaling molecules to promote cell proliferation and growth, this study aimed to fabricate protoporphyrin IX (PpIX)-immobilized cellulose (CEPP) monoliths as a means to both guide and stimulate nerve regeneration. CEPP monoliths can be fabricated via a simple thermally induced phase separation method and surface modification. The improved nerve tissue regeneration of CEPP monoliths was achieved by the activation of mitogen-activated protein kinases, such as extracellular signal-regulated kinases (ERKs). The resulting CEPP monoliths exhibited interconnected microporous structures and uniform morphology. The results of in vitro bioactivity assays demonstrated that the CEPP monoliths with under 0.54 ± 0.07 µmol/g PpIX exhibited enhanced photodynamic activity on Schwann cells via the generation of low levels of ROS. This photodynamic activation of the CEPP monoliths is a cell-safe process to stimulate cell proliferation without cytotoxic side effects. In addition, the protein expression of phospho-ERK increased considerably after the laser irradiation on the CEPP monoliths with low content of PpIX. Therefore, the CEPP monoliths have a potential application in nerve tissue regeneration as new nerve conduits.

Tonic GABAergic Inhibition Is Essential for Nerve Injury-Induced Afferent Remodeling in the Somatosensory Thalamus and Ectopic Sensations.

Peripheral nerve injury induces functional and structural remodeling of neural circuits along the somatosensory pathways, forming the basis for somatotopic reorganization and ectopic sensations, such as referred phantom pain. However, the mechanisms underlying that remodeling remain largely unknown. Whisker sensory nerve injury drives functional remodeling in the somatosensory thalamus: the number of afferent inputs to each thalamic neuron increases from one to many. Here, we report that extrasynaptic γ-aminobutyric acid-type A receptor (GABAAR)-mediated tonic inhibition is necessary for that remodeling. Extrasynaptic GABAAR currents were potentiated rapidly after nerve injury in advance of remodeling. Pharmacological activation of the thalamic extrasynaptic GABAARs in intact mice induced similar remodeling. Notably, conditional deletion of extrasynaptic GABAARs in the thalamus rescued both the injury-induced remodeling and the ectopic mechanical hypersensitivity. Together, our results reveal a molecular basis for injury-induced remodeling of neural circuits and may provide a new pharmacological target for referred phantom sensations after peripheral nerve injury.

New bioresorbable wraps based on oxidized polyvinyl alcohol and leukocyte-fibrin-platelet membrane to support peripheral nerve neurorrhaphy: preclinical comparison versus NeuraWrap.

Nerve wrapping improves neurorrhaphy outcomes in case of peripheral nerve injuries (PNIs). The aim of this preclinical study was to assess the efficacy of two novel biodegradable wraps made of a synthetic 1% oxidized polyvinyl alcohol (OxPVA) and a natural leukocyte-fibrin-platelet membrane (LFPm) versus the commercial product NeuraWrap. After rats sciatic nerve transection and neurorrhaphy, the wraps were implanted and compared for functional outcome, by sciatic function index assessment; structural characteristics, by histological/immunohistochemical analysis; ultrastructural features, by transmission electron microscopy. Moreover, a morphometric study was also performed and collagen distribution was observed by Second Harmonic Generation microscopy. After 12 weeks from implantation, all wraps assured nerve function recovery; no scar tissue/neuromas were visible at dissection. LFPm wraps were completely resorbed, while residues of OxPVA and NeuraWrap were observed. In all groups, biocompatibility was confirmed by the absence of significant inflammatory infiltrate. According to histological/immunohistochemical analysis and morphometric findings, OxPVA and LFPm wraps were both effective in preserving nerve integrity. These results assess that bioengineered OxPVA and LFPm wraps successfully guarantee favorable lesion recovery after PNI/neurorrhaphy and, in future, may be considered an interesting alternative to the commercial NeuraWrap.

Use of Curcumin, a Natural Polyphenol for Targeting Molecular Pathways in Treating Age-Related Neurodegenerative Diseases.

Progressive accumulation of misfolded amyloid proteins in intracellular and extracellular spaces is one of the principal reasons for synaptic damage and impairment of neuronal communication in several neurodegenerative diseases. Effective treatments for these diseases are still lacking but remain the focus of much active investigation. Despite testing several synthesized compounds, small molecules, and drugs over the past few decades, very few of them can inhibit aggregation of amyloid proteins and lessen their neurotoxic effects. Recently, the natural polyphenol curcumin (Cur) has been shown to be a promising anti-amyloid, anti-inflammatory and neuroprotective agent for several neurodegenerative diseases. Because of its pleotropic actions on the central nervous system, including preferential binding to amyloid proteins, Cur is being touted as a promising treatment for age-related brain diseases. Here, we focus on molecular targeting of Cur to reduce amyloid burden, rescue neuronal damage, and restore normal cognitive and sensory motor functions in different animal models of neurodegenerative diseases. We specifically highlight Cur as a potential treatment for Alzheimer's, Parkinson's, Huntington's, and prion diseases. In addition, we discuss the major issues and limitations of using Cur for treating these diseases, along with ways of circumventing those shortcomings. Finally, we provide specific recommendations for optimal dosing with Cur for treating neurological diseases.

Contralateral Electroacupuncture Relieves Chronic Neuropathic Pain in Rats with Spared Nerve Injury.

BACKGROUND Acupuncture and electroacupuncture (EA) are widely applied in the treatment of various conditions, including pain. Acupuncture stimulation is applied not only in areas close to pain sites, but also in distal regions or on the contralateral side of the body. Identifying which acupuncture paradigms produce best therapeutic effects is of clinical significance. MATERIAL AND METHODS Spared nerve injury (SNI) was applied to establish a rat model of neuropathic pain. We applied 14 sessions of EA (BL 60 and BL 40, 1-2 mA, and 2 Hz, 30 min per session) every other day from days 3 to 29 after surgery on the contralateral or ipsilateral side of pain. von Frey hair was applied to examine mechanical allodynia in the SNI model and analgesic effects of EA. All experimental procedures were approved by the Animal Care and Use Committee of our university, according to the guidelines of the International Association for the Study of Pain. RESULTS SNI produced significant and long-lasting mechanical allodynia (p<0.001) in injured paws. Repeated EA on the contralateral side of the pain significantly attenuated mechanical allodynia from 14 days after surgery (p<0.05). By contrast, ipsilateral EA did not show analgesic effects (p>0.05). CONCLUSIONS These findings indicate that contralateral EA is superior to local EA in some types of pain disorders. Further investigations are needed for a more comprehensive understanding of the central mechanisms of acupuncture.

Electrophoresis of polar fluorescent tracers through the nerve sheath labels neuronal populations for anatomical and functional imaging.

The delivery of tracers into populations of neurons is essential to visualize their anatomy and analyze their function. In some model systems genetically-targeted expression of fluorescent proteins is the method of choice; however, these genetic tools are not available for most organisms and alternative labeling methods are very limited. Here we describe a new method for neuronal labelling by electrophoretic dye delivery from a suction electrode directly through the neuronal sheath of nerves and ganglia in insects. Polar tracer molecules were delivered into the locust auditory nerve without destroying its function, simultaneously staining peripheral sensory structures and central axonal projections. Local neuron populations could be labelled directly through the surface of the brain, and in-vivo optical imaging of sound-evoked activity was achieved through the electrophoretic delivery of calcium indicators. The method provides a new tool for studying how stimuli are processed in peripheral and central sensory pathways and is a significant advance for the study of nervous systems in non-model organisms.

YY1 in Cell Differentiation and Tissue Development.

Yin Yang1 (YY1) is a ubiquitous expressed transcription factor that modulates a variety of biologic processes with prominent roles in cellular differentiation and tissue development. Recent advances in molecular biology, mouse genetics, and particularly high-throughput sequencing have greatly enhanced our understanding of YY1 functions and underlying mechanisms in regulating transcription and epigenetics. In this review, we summarize findings on the roles of YY1 in cell differentiation and tissue development, in particular in muscle, nerve, and immune cells/tissues.

Modelling the response to low-frequency repetitive nerve stimulation of myasthenia gravis and Lambert-Eaton myasthenic syndrome.

Myasthenia gravis (MG) is an autoimmune postsynaptic disorder of neuromuscular transmission caused, in most patients, by antibodies against postsynaptic acetylcholine receptors. Lambert-Eaton myasthenic syndrome (LEMS) is a presynaptic autoimmune disease in which there is a reduction in Ca2+ entry with each impulse due to the action of antibodies against Ca2+ channels. These diseases have a distinct pattern of response to low-frequency repetitive nerve stimulation which allows its recognition in a particular subject. Nevertheless, the physiologic basis of this response is not entirely known. A model of the time-course of release probability of neuromuscular junctions that incorporates facilitation and a depression-recovery mechanism has been developed with the aim to investigate these response patterns. When the basal value of release probability was in the physiologic range, as in MG, release probability showed an increment after its initial decrease only if the recovery from depression was accelerated by presynaptic residual Ca2+. Otherwise, when the basal release probability was low, as in LEMS, a progressive reduction in the release probability without any late increase was only obtained if the efficacy of Facilitation and Ca2+-dependent recovery from depression were reduced.

Efecto neuroprotector de la semilla de Prunus dulcis Almendra sobre el tejido nervioso en ratones inducidos a estrés por desorientación motora / Neuroprotective effect of the seed of Prunus dulcis Almond on nerve tissue in mice induced to stress of motor disorientation

Objetivo: Determinar el efecto neuroprotector de la administración de la semilla de Prunus dulcis “almendra” sobre el tejido nervioso en ratones inducidos a estrés por desorientación motora. Diseño: Estudio analítico, transversal, experimental y prospectivo. Lugar: Laboratorios del Centro de Investigación de Bioquímica y Nutrición Alberto Guzmán Barrón, Facultad de Medicina, UNMSM, Lima, Perú. Materiales: Ratones albinos BALB/c (Mus musculus) machos y Prunus dulcis “almendra”. Métodos: Se utilizó 42 ratones, según expertos, de 3 meses de edad y 31 ± 4,49 de peso, distribuidos aleatoriamente en seis grupos (n=7). Todos los grupos recibieron la misma dieta balanceada y agua ad libitum durante 5 días. Recibieron los siguientes tratamientos, por cinco días, vía peroral: grupo I y II: suero fisiológico (NaCI 0,9g por ciento 10mL/kg), grupo III: vitamina E 400mg/kg, grupo IV: almendra 100 mg/kg, grupo V: almendra 500 mg/kg y grupo VI: almendra 1000 mg/kg; 12 horas antes de finalizar el Tto., se cortaron los bigotes de los ratones, excepto al grupo 1; y luego de 12 horas se realizó el sacrificio. Principales medidas de los resultados: Nivel de lipoperoxidación expresado en sustancias reactivas al ácido tiobarbitúrico (TBARs) y nivel de Grupos sulfhídrilos no proteicos (GS-NP), además de cambios histopatológicos de tejido de cerebro y cerebelo. Resultados: La administración de Prunus dulcis “almendra” aumenta significativamente (p<0.05) los niveles de GS-NP en todos los grupos (excepto G VI) en comparación con el G II en cerebro; los niveles de TBARs disminuyen significativamente (p<0.05) en el grupo V y VI comparado con el grupo II, y en relación a los cambios histológicos se observa una mejora leve en el G V en comparación con el G II. Conclusiones: La administración de la suspensión de la semilla del Prunus dulcis "almendra" expresó un efecto neuroprotector en los indicadores bioquímicos (TBARs y GS-NP), sobre el tejido nervioso en ratones inducidos a estrés por...

Objective: Determine the neuroprotective effect of administration of Prunus dulcis seed "almond" on the nervous tissue in motor stress induced disorientation mice. Design: Analytical, transverse, experimental and prospective study. Location: Laboratories of the Research Center of Biochemistry and Nutrition Alberto Guzman Barron, Faculty of Medicine, UNMSM, Lima, Peru. Materials: Mice albinos BALB / c (Mus musculus) males and Prunus dulcis “almond”. Methods: 42 mice was used, experts say, 3 months and 31 ± 4,49 in weight, randomized into six groups (n=7). AII groups received the same balanced diet and water ad libitum for 5 days. They received the following treatments for five days, perorally: group I and II: saline (NaCI 0.9g per cent 10 mL/kg), group III: Vitamin E 400 mg/kg, group IV: almond 100 mg/kg, group V: almond 500 mg/kg and group VI: almond 1000 mg/kg; 12 hours before the end of treatment cut whiskers of mice, except the group 1; and after 12 hours they were sacrificed. Main outcome measures: Level of lipid peroxidation expressed in thiobarbituric acid (TBARS) and level of non-protein sulfhydryl groups (GS-NP) substances in addition to histo-pathological changes of brain tissue and cerebellum. Results: Administration of Prunus dulcis “almond” significantly increased (p<0.05) levels of GS-NP in all groups (except G VI) compared to the G II in brain; TBARS levels decreased significantly (p<0.05) in the V and VI group compared with group II, and in relation to the histological changes seen a slight improvement in the G V compared to G II. Conclusions: The administration of the suspension of Prunus dulcis seed “almond” demonstrated the neuroprotective effect in biochemical (TBARs y GS-NP) on the nervous tissue in mice induced to stress motor disorientation.

Suppressive effects of D-glucosamine on the 5-HT sensitive nociceptive units in the rat tooth pulpal nerve.

It is well known that D-glucosamine hydrochloride (DGL) has a variety of biological activities and is regarded as a nutritional supplement effective in improving various disorders, including osteoarthritis and atherosclerosis. Although it has been reported that DGL has a significant pain relief effect in treating osteoarthritis, little is known about the characteristics of the effects of this compound on dental pain. The present study was undertaken to evaluate the applicability of DGL as a medicament to control pulpalgia. Using an in vitro rat mandible-inferior alveolar nerve preparation (jaw-nerve preparation), we evaluated the effects of DGL on 5-hydroxytryptamine (5-HT) sensitive nociceptive responses in the tooth pulpal nerve. 5-HT-induced nociceptive responses were fairly suppressed by direct application of DGL, suggesting that DGL have a pain relief effect on patients with dental pain.

A novel TaulacZ allele reveals a requirement for Pitx2 in formation of the mammillothalamic tract.

The hypothalamic mammillary region is critical for spatial memory and vestibular processing. Pitx2 encodes a paired-like transcription factor that is highly expressed in the developing mammillary region and is required for subthalamic nucleus formation. Here we analyzed a loss of function Pitx2-TaulacZ knock-in allele to study the effects of Pitx2 deficiency on neuronal projections in the embryonic mammillary region. Pitx2-expressing neurons contribute axons to principal mammillary, mammillotegmental and mammillotectal tracts. Embryos with Pitx2 deficiency exhibit axonal fibers in the principal mammillary tract that are improperly bundled and disorganized, yet project caudally toward the tectum and tegmentum. Embryos with Nestin-Cre mediated conditional Pitx2 deficiency exhibit truncated mammillothalamic tracts (mtt) that fail to elongate, and reduced Pax6-positive cells at the branching point of the principal mammillary and mtt. These data suggest that Pitx2 mediates cell-autonomous and nonautonomous guidance cues necessary for mammillary collaterals destined to project to the anterior thalamus.

[Er:YAG laser: tissue interaction and histomorphological characterization]. / Laser a Erbium YAG: caratteristiche istomorfologiche da interazione energia-tessuto.

Authors describe Er:YAG laser interaction with tissues, in particular their histomorphological characteristics to identify a specific clinic area for laser application through the examination of different clinical international trials. This study includes experimental trials about pig and rat skin laser application to know laser Er: YAG capability and limits; investigation is extended to laser application in human soft tissues as mucosa, periosteum and bones, its utility in cutaneous pathologies and in antiageing treatments.

Flavanone and diphenylpropane glycosides and glycosidic acyl esters from Viscum articulatum.

Seven new compounds including three flavanone glycosides, visartisides A-C (1-3), three glycoside acyl esters, visartisides D-F (4-6), and one diphenylpropane glycoside, (4'-hydroxy-2',3',6',3''-tetramethoxy-1,3-diphenylpropane)-4''-O-beta-d-glucopyranoside (7), along with four known flavanone glycosides (8-11) were isolated from the leaves and stems of Viscum articulatum. The structure elucidation of 1-7 was based on spectroscopic data analysis. Biological evaluation showed that 1, 2, and 10 exhibited antioxidant activity using a DPPH method and that compounds 1, 3, and 11 were active in a lipopolysaccharide-induced nitric oxide assay.

[Morphologic characteristics and clinical significance of Neiguan (PC 6)].

OBJECTIVE: To provide appropriate needling angle and depth for the acupuncture and acupoint injection at Neiguan (PC 6), and to avoid damaging nerves and vessels so as to produce its maximum effect. METHODS: Thirty adults' upper-limb samples were used to dissect and observe the referred hierarchical structure and adjoining crucially nerves and vessels in needling Neiguan (PC 6) according to the national standard Acupoint Location (GB 12346-90). RESULTS: In this punctuation region, there are three parts rich in connective tissues containing the nerves and blood vessels. The surface part is between the skin and the musculus flexor digitorum superficialis and it is the tissue which contains medial and lateral antebrachial cutaneous nerve and its nutrient artery. The middle part is between the musculus flexor digitorum superficialis and the flexor digitorum profundus muscle and contains the median nerve, its palmar branch of and artery. The deep part is between the pronator quadratus muscle and the interosseous membrane and contains the anterior interosseous nerve. When perpendicular needling, the depth of needling the body from skin to the superficial surface of the musculus flexor digitorum superficialis and to the superficial surface of the flexor digitorum profundus muscle is (6.68 +/- 0.64) mm and (12.37 +/- 0.87) mm respectively. The depth of needling the body from skin to the superficial surface of the pronator quadratus muscle and to the superficial surface of the anterior interosseous terminal branch of the nerves is (17.83 +/- 1.00) mm and (30.87 +/- 1.85) mm respectively, and the proportional cun is (2.20 +/- 0.14) cm. The ulnaris cord of median nerves are located at the radial of the needle. The deep layers could touch the anterior interosseous nerve ending. CONCLUSION: Perpendicularly needling Neiguan (PC 6) for 3 fen (6.68 mm), 5 fen (12.37 mm) and 1.4 cun (30.87 mm) will stimulate the nervus vascularis of the rich part of surface, middle and deep connective tissues respectively and produce the acupuncture effect. During the acupoint injection, perforating the needle perpendicularly at the middle point of the two tendons or deviating slightly to the direction of tendon of palmaris longus can avoid the damage of the median nerve cord.

Morphologic characteristics and clinical significance of Neiguan (PC 6) / 中国针灸

<p><b>OBJECTIVE</b>To provide appropriate needling angle and depth for the acupuncture and acupoint injection at Neiguan (PC 6), and to avoid damaging nerves and vessels so as to produce its maximum effect.</p><p><b>METHODS</b>Thirty adults' upper-limb samples were used to dissect and observe the referred hierarchical structure and adjoining crucially nerves and vessels in needling Neiguan (PC 6) according to the national standard Acupoint Location (GB 12346-90).</p><p><b>RESULTS</b>In this punctuation region, there are three parts rich in connective tissues containing the nerves and blood vessels. The surface part is between the skin and the musculus flexor digitorum superficialis and it is the tissue which contains medial and lateral antebrachial cutaneous nerve and its nutrient artery. The middle part is between the musculus flexor digitorum superficialis and the flexor digitorum profundus muscle and contains the median nerve, its palmar branch of and artery. The deep part is between the pronator quadratus muscle and the interosseous membrane and contains the anterior interosseous nerve. When perpendicular needling, the depth of needling the body from skin to the superficial surface of the musculus flexor digitorum superficialis and to the superficial surface of the flexor digitorum profundus muscle is (6.68 +/- 0.64) mm and (12.37 +/- 0.87) mm respectively. The depth of needling the body from skin to the superficial surface of the pronator quadratus muscle and to the superficial surface of the anterior interosseous terminal branch of the nerves is (17.83 +/- 1.00) mm and (30.87 +/- 1.85) mm respectively, and the proportional cun is (2.20 +/- 0.14) cm. The ulnaris cord of median nerves are located at the radial of the needle. The deep layers could touch the anterior interosseous nerve ending.</p><p><b>CONCLUSION</b>Perpendicularly needling Neiguan (PC 6) for 3 fen (6.68 mm), 5 fen (12.37 mm) and 1.4 cun (30.87 mm) will stimulate the nervus vascularis of the rich part of surface, middle and deep connective tissues respectively and produce the acupuncture effect. During the acupoint injection, perforating the needle perpendicularly at the middle point of the two tendons or deviating slightly to the direction of tendon of palmaris longus can avoid the damage of the median nerve cord.</p>

The human GLUD2 glutamate dehydrogenase: localization and functional aspects.

In all mammals, glutamate dehydrogenase (GDH), an enzyme central to the metabolism of glutamate, is encoded by a single gene (GLUD1 in humans) which is expressed widely (housekeeping). Humans and other primates also possess a second gene, GLUD2, which encodes a highly homologous GDH isoenzyme (hGDH2) expressed predominantly in retina, brain and testis. There is evidence that GLUD1 was retro-posed <23 million years ago to the X chromosome, where it gave rise to GLUD2 through random mutations and natural selection. These mutations provided the novel enzyme with unique properties thought to facilitate its function in the particular milieu of the nervous system. hGDH2, having been dissociated from GTP control (through the Gly456Ala change), is mainly regulated by rising levels of ADP/l-leucine. To achieve full-range regulation by these activators, hGDH2 needs to set its basal activity at low levels (<10% of full capacity), a property largely conferred by the evolutionary Arg443Ser change. Studies of structure/function relationships have identified residues in the regulatory domain of hGDH2 that modify basal catalytic activity and regulation. In addition, enzyme concentration and buffer ionic strength can influence basal enzyme activity. While mature hGDH1 and hGDH2 isoproteins are highly homologous, their predicted leader peptide sequences show a greater degree of divergence. Study of the subcellular sites targeted by hGDH2 in three different cultured cell lines using a GLUD2/EGFP construct revealed that hGDH2 localizes mainly to mitochondria and to a lesser extent to the endoplasmic reticulum of these cells. The implications of these findings for the potential role of this enzyme in the biology of the nervous system in health and disease are discussed.