Nerve Process Research Articles

The importance of individualized and multiple landmarks for the identification of facial nerve trunk: a narrative review

The identification of the facial nerve trunk(FNT) is an important step in surgical procedures involving the parotid gland and adjacent structures to minimize the risk of inadvertent nerve damage which leads to facial muscle paralysis. Despite the availability of various anatomic landmarks such as the tragal pointer, posterior belly of digastric muscle, tympanomastoid suture, digastric branch of facial nerve and styloid process, no single landmark is perfect, with variations observed between individuals. Therefore, a comprehensive knowledge of facial nerve anatomy is essential for FNT identification. In this review, we tried to introduce clinically meaningful methods for the localization of facial nerve trunk. The preference of landmark could be changed by the major of the surgeon or the location of the tumor of the patients. Understanding the characteristics and drawbacks of the landmarks and choosing multiple landmarks that were convenient for surgeon would be necessary.

Comparative results of treatment of patients with chronic pain syndrome in traumatic lesions of the peripheral nervous system

Traumatic damage to the peripheral nervous system leads to long periods of inpatient treatment, disability of patients with disabilities to restore lost functions. After crossing the nerve trunk, nerve fibers re-grow from the center to the periphery, or an amputation neuroma forms on the proximal nerve process. When the nerve endings are irritated, pain appears by the type of electric current discharge, which flows from acute to chronic and persists for a long time. The study aims to improve the results of treatment of patients with chronic pain on the background of injury to the peripheral nervous system. The study is based on the analysis of the results of treatment by various methods of patients with chronic pain syndrome caused by traumatic damage to the peripheral nervous system. In the near and long-term follow-up periods, the analysis of neurophysiological parameters in patients with peripheral nervous system injury indicates a significant improvement compared to the initial data in both groups, especially in the group of proper patients in the form of an increase in the amplitude and speed of propagation of excitation along sensory fibers.

Molecular and cellular mechanisms of the organogenesis and development of the mammalian carotid body.

Despite significant advancements in understanding physiological properties of the carotid body, little attention has been paid to its organogenesis. This review addresses the molecular and cellular mechanisms underlying organogenesis of the carotid body in mammals. The carotid body consists of two types of cells, that is, glomus cells and sustentacular cells, that are derived from different origins. Glomus cells are derivatives of neural crest cells which form sympathetic ganglia. Sustentacular cells are derivatives of mesenchymal neural crest cells which colonize the third pharyngeal arch and form the wall of the third arch artery. Gene-targeting studies indicate that three elements are required for carotid body organogenesis: the carotid sinus nerve (CSN), third arch artery, and superior cervical sympathetic ganglion (SCG). The CSN sends sensory fibers and Schwann cells to the wall of the third arch artery. The third arch artery provides mesenchymal cells, which give rise to sustentacular cells. The nerve process from the SCG sends glomus cell progenitors into the carotid body primordium. The presence of stem cells in the adult carotid body was recently highlighted. The origin of stem cells, however, remains controversial. Based on embryonic development of the carotid body, this review proposes the origin of stem cells.

Contractile and Electrical Activity of Neurons on Exposure to Colchicine

The aim of the present work was to study the contractile activity of traumatized nerve cell processes and to attempt to inhibit their retraction using a solution of colchicine. Experiments were performed on living isolated neurons from freshwater mollusks (Lymnaea stagnalis and Planorbis corneus vulgaris), which were studied in phase contrast conditions using time-lapse microvideo recordings. Contractile activity of nerve cell processes was seen in 92% of cases in control conditions in Ringer’s solution. Colchicine inhibited nerve process contraction in 86% of neurons. Experiments addressing neuron electrical activity were performed on leech Retzius neurons. Incubation of ganglia in colchicine solution was found to increase the frequency of spontaneous spike activity from 0.22 to 0.75 spikes/sec. The amplitude of spontaneous potentials decreased from 46.9 to 37 mV, the threshold decreased by 18%, the duration of spontaneous spikes increased from 4.3 to 7.1 msec, and the latent period of responses to stimuli increased from 25.0 to 37.9 msec. In conditions of stimulation at 7–10 Hz, neurons generated spike activity at higher frequencies than in control conditions. Thus, our experiments showed that colchicine can inhibit the contractile activity of traumatized nerve cell processes, keeping the electrically excitable membrane in a satisfactory condition. It follows that attempts can be made in vivo to produce partial inhibition of nerve fiber contraction, thus preventing increases in neuron diastasis, which prevent surgical approximation to the point of contact and promote the development of massive scars at transection sites.

Penatalaksanaan patah jarum akibat anastesi lokal pada ekstraksi gigi Management of broken needle cause by local anesthesia on teeth extraction

Since the inroduction of disposable needles, breakage of needles within tissues have become extremely rare.However, reports of needle breakage still appear. This paper discussed the cause of needle breakage, problem ofneedle breakage, prevention of needle breakage, and management of needle breakage. If the needle broken duringanesthesia of the alveolar dental nerve process, the needle will probably be located in the pterygomandibular space.It can migrate to vital structure.

Location of Axillary nerve in relation to acromian process of Scapula: a Cadaveric study

Commonest cause of axillary nerve lesion is trauma. Many workers have studied the safe area for axillary nerve by measuring its distance from various landmarks. Sixty formalin fixed cadaveric shoulders were dissected. After proper exposure of axillary nerve and acromian process of scapula, distance of axillary nerve was measured from lateral edge, anterior and posterior edge of acromian process in neutral position. Distance was noted in adduction and abduction. Arm length and full arm length were measured. Mean, standard deviation, range was calculated. Mean distance of the nerve in neutral position was compared to the arm length and the full arm length using SPSS 11 software. Mean distance from lateral edge of Acromian process was 5.62 ± 0.6 cm. In 90 0 abduction it was 4.28 ± 0.6 cm. and 5.75 ± 0.6 cm. 10 0 adduction. In neutral position strong correlation was observed with arm length (r = 0.39, p <0.002) and with full arm length. (r = 0.29, p <0.02) Distance of axillary nerve depends on arm position and the nerve is more prone to injury in abduction. It showed stronger correlation with upper arm length. Deltoid incision of about 3.5 cm should theoretically prevent the injury to axillary nerve.

TheCaenorhabditis elegansJIP3 Protein UNC-16 Functions As an Adaptor to Link Kinesin-1 with Cytoplasmic Dynein

Kinesin-1 is a microtubule plus-end-directed motor that transports various cargos along the axon. Previous studies have elucidated the physical and genetic interactions between kinesin-1 and cytoplasmic dynein, a microtubule minus-end-directed motor, in neuronal cells. However, the physiological importance of kinesin-1 in the dynein-dependent retrograde transport of cargo molecules remains obscure. Here, we show that Caenorhabditis elegans kinesin-1 forms a complex with dynein via its interaction with UNC-16, which binds to the dynein light intermediate (DLI) chain. Both kinesin-1 and UNC-16 are required for localization of DLI-1 at the plus ends of nerve process microtubules. In addition, retrograde transport of APL-1 depends on kinesin-1, UNC-16, and dynein. These results suggest that kinesin-1 mediates the anterograde transport of dynein using UNC-16 as a scaffold and that dynein in turn mediates the retrograde transport of cargo molecules in vivo. Thus, UNC-16 functions as an adaptor for kinesin-1-mediated transport of dynein.

APPLICATION OF CONTRAST-ENHANCED CONSTRUCTIVE INTERFERENCE IN STEADY STATE MAGNETIC RESONANCE IMAGING TO LEKSELL GAMMAPLAN FOR LOCALIZING C2–C3 ANEURYSMS

We used gadolinium (Gd)-enhanced constructive interference in steady state (CISS) magnetic resonance imaging with the Leksell GammaPlan (LGP; Elekta AB, Stockholm, Sweden) system for accurate preoperative evaluation of the anatomic localization of intradural and/or extradural C2-C3 aneurysms. Anatomic localization of 8 unruptured aneurysms of the C2-C3 segment was evaluated using Gd-enhanced CISS imaging with LGP. Four patients diagnosed with intradural aneurysms, 1 with a combined intraextradural aneurysm, and 1 with an intracavernous aneurysm underwent operation. The aneurysmal localizations diagnosed preoperatively by Gd-enhanced CISS imaging with LGP were compared with intraoperative findings. By use of Gd-enhanced CISS imaging with LGP, 3-dimensional visualization of the internal carotid artery, aneurysms at the C2-C3 segment, optic nerve, oculomotor nerve, cavernous sinus, and anterior clinoid process was possible in 8 patients. The localization of intradural or combined intra-extradural aneurysms was diagnosed on the basis of the oculomotor nerve and the cavernous sinus depicted in 3-dimensional images. The oculomotor nerve and the cavernous sinus serve as landmarks for the proximal ring on images of the carotico-oculomotor membrane. Intradural or intra-extradural localization of C2-C3 aneurysms with this novel technique was in complete agreement with intraoperative findings in 6 surgical cases. This study demonstrated the utility of Gd-enhanced CISS imaging used with LGP for accurate preoperative localization of intradural and/or extradural aneurysms at the C2-C3 segments.

Study on Construction, Expression, and Biological Activity of Recombinant Adenovirus of Neurturin

Neurturin (NTN) can improve the function and delay the rate of degeneration of dopaminergic neurons in Parkinson's disease (PD). However, its method of delivery to the central nervous system has not been established. Adenoviral vectors have been widely applied in gene therapy because of their high-efficiency gene transfer, easy manipulation, and safety. We used replication-defective adenovirus type 5 (Ad5) to construct a recombinant viral vector encoding full-length human NTN (Ad-NTN) and amplified Ad-NTN and the control (Ad-lacZ) in HEK 293 cells. NTN-specific expression in the Ad-NTN-infected HEK 293 cells was detected by RT-PCR and the immunofluorescent assay. However, no NTN expression was detected in the Ad-lacZ-infected HEK 293 cells. After incubation with the Ad-NTN-infected conditioned medium (CM), the dorsal root ganglia of chicken embryos examined in vitro exhibited radial neurite outgrowth around the ganglia. However, incubation with the Ad-lacZ-infected or blank CM resulted in a short or absent nerve process and the growth of only a few fibroblasts. Our findings indicated that recombinant Ad-NTN was specifically expressed in the host cells, and the expressed NTN possessed biological activity.

A Polyimide Pressure-Contact Multielectrode Array for Implantation Along a Submillimeter Neural Process in Small Animals

We describe a microelectrode system for recordings from nerve bundles with diameters ranging from 20-200 microm. A novel polyimide structure allows for a planar microfabricated device to constrain a free neural process against several recording sites. This polyimide array contains multiple zigzag vias through which a small nerve process may be woven while remaining functionally intact in a live preparation. Our electrode construct features the benefits of nerve cuffs (evenly spaced electrodes in a polymer) and the functionality of a nerve hook (ability to connect to submillimeter processes). The device records extracellular action potentials in the red-swamp crayfish, Procambarus clarkii. Action potential propagation is monitored at several sites along a constrained nerve in this model organism's peripheral nervous system. Details of temporal accuracy and error sources in absolute conduction velocity measurements from microelectrode arrays are discussed.

SEM studies on the copulatory apparatus of male Oesophagostomum columbianum

Abstract SEM studies on the cloacal opening of Oesophagostomum columbianum indicate that it is located on a raised conical structure called the “genital cone”. The genital cone is provided with a ventral lip and a pair of subdorsal gential appendages. The vental lip is a triangular structure having a single papilla on it and the genital appendages are covered with wrinkled cuticle with a nerve process projecting to the exterior in center. The bursa is supported by muscular rays which end up as knob-like sessile genital papillae. The inner surface of the bursa is porous. Spicules are two, equal, each provided with an ala which decreases in height distally and end up much prior to the spicular tip.

Estrogen and Cognition, with a Focus on Alzheimer's Disease

Cognitive aging is associated with decreases in memory, attention, and visual/motor performance and skills. Dementia consists of loss of memory and other cognitive abilities, associated with social or occupational impairment. Potential neuroprotective effects of estrogen include lowering beta-amyloid, enhancing cholinergic function, promoting synaptic plasticity and nerve process growth, reducing oxidative stress, and enhancing brain glucose transport. Observational and longitudinal studies suggest that hormone therapy may attenuate age-associated cognitive impairment or decrease Alzheimer's disease but this has not been confirmed by randomized clinical trials. A critical window of time may exist around the menopause when hormone therapy may delay or decrease cognitive changes; however, hormone therapy initiated in the late postmenopause does not improve global cognition and may increase dementia risk.

Substrate Curvature Influences the Direction of Nerve Outgrowth

Nerve outgrowth in the developing nervous system utilizes a variety of attractive and repulsive molecules found in the extracellular environment. In addition, physical cues may play an important regulatory role in determining directional outgrowth of nervous tissue. Here, by culturing nerve cells on filamentous surfaces and measuring directional growth, we tested the hypothesis that substrate curvature is sufficient to influence the directional outgrowth of nerve cells. We found that the mean direction of neurite outgrowth aligned with the direction of minimum principle curvature, and the spatial variance in outgrowth direction was directly related to the maximum principle curvature. As substrate size approached the size of an axon, adherent neurons extended processes that followed the direction of the long axis of the substrate similar to what occurs during development along pioneering axons and radial glial fibers. A simple Boltzmann model describing the interplay between adhesion and bending stiffness of the nerve process was found to be in close agreement with the data suggesting that cell stiffness and substrate curvature can act together in a manner that is sufficient to direct nerve outgrowth in the absence of contrasting molecular cues. The study highlights the potential importance of cellular level geometry as a fidelity-enhancing cue in the developing and regenerating nervous system.

Elucidation of the separate roles of myosins IIA and IIB during neurite outgrowth, adhesion and retraction

The functions of nonmuscle myosin isoforms are key to an understanding of process outgrowth from nerve cells during animal development. Despite considerable structural similarity, myosin IIA and myosin IIB play distinct and complementary roles during the actin-based mechanisms of nerve process extension. An overview is given of evidence that implicates myosin IIB as the motor essential for nerve process outgrowth and myosin IIA both as the motor required to maintain cell adhesion to the substrate as well as the motor required to power retraction of the nerve cell process. These actions are placed in context within a model for nerve process extension that is consistent with many observations in the literature and provides testable hypotheses regarding possible roles for these nonmuscle myosin motors. The relevance of a fundamental understanding of the mechanisms underpinning nerve cell process extension to the application of nanotechnology in this area is also discussed.

Perspectives on the approaches to lesions in and around the cavernous sinus

Surgery for lesions that arise in the cavernous sinus and its vicinity is a formidable challenge. Dolenc was the first to describe a stepwise surgical approach to the cavernous sinus in a comprehensive fashion. Since the understanding of the cavernous sinus surgical anatomy has increased among neurosurgeons and enabled the development of modern skull base techniques. The knowledge of the relationships of the internal carotid artery with the anterior clinoid process in the anterior part of the sinus was crucial for the surgery of paraclinoid aneurysms. The same is true for basilar tip aneurysm surgery in regards to the relationships of the internal carotid, oculomotor nerve, and posterior clinoid process in the posterior part of the sinus. In general terms and for practical purposes, we review the two most commonly used surgical approaches to the cavernous sinus: (1) the superior approach (which can be subdivided into an anterior and a posterior route) and (2) the lateral extradural route. The surgical approach to paraclinoid aneurysms and the pretemporal orbitozygomatic transcavernous approach to basilar tip aneurysms are also reviewed.

Purine nucleosides protect injured neurons and stimulate neuronal regeneration by intracellular and membrane receptor‐mediated mechanisms

AbstractLike adenine‐based purines, extracellular nonadenine‐based purines have a multitude of trophic effects on the growth, differentiation, and survival of target cells. The nonadenine‐based purines, which include guanosine, inosine, and GTP, apparently exert their trophic effects by interacting with both intercellular targets as well as those on the cell surface. Specifically, guanosine and inosine target the protein kinase N‐kinase, in promoting remarkable nerve process extension, even in long tracts of the central nervous system after injury. In contrast, GTP may exert its effects via a cell surface receptor coupled to the release of calcium from internal stores. In other cases trophic effects may be mediated by the enhancement of release of adenine‐based purines by guanosine. Additionally, evidence is presented for the existence of a high‐affinity binding site for guanosine with receptor‐like characteristics on the plasma membranes of astrocytes and brain tissue. This site may be G‐protein‐coupled and exert its effects through activation of the MAP kinase cascade. One effect apparently mediated through this mechanism is the production and release by astrocytes of trophic protein growth factors such as NGF and TGFβ. These have substantial neuroprotective effects. Additionally, this pathway is apparently involved in modulating the expression of P2Y1 and P2Y2 receptors in response to extracellular guanosine. Extracellular nonadenine‐based purines can interact with other growth factors, but these interactions are not always synergistic. For example, combinations of guanosine and FGF are antagonistic and reduce the growth of microvascular cells in vitro. Some of the properties of the nonadenine‐based purines likely derive from their unique intracellular metabolism in which conversion of guanine to xanthine is the final catabolic step. This step is catalyzed by guanase, the activity of which varies markedly in different brain regions, raising the possibility that guanine or guanosine are involved in neurotransmission. Together these data suggest several potentially useful pharmacological approaches involving nonadenine‐based purines to modulate trophic effects in the central nervous system. Drug Dev. Res. 52:303–315, 2001. © 2001 Wiley‐Liss, Inc.

Merkel complexes of human digital skin: Three-dimensional imaging with confocal laser microscopy and double immunofluorescence

Three-dimensional (3-D) reconstruction of images provided by confocal scanning laser microscopy (CSLM) is a powerful tool in a morpho-functional approach to cutaneous innervation studies. To investigate mechanoreceptors in the hand, a study of Merkel complexes was performed in human finger. A double fluorescent-conjugated immunolabeling with antibodies against neurofilament (NF 200) and cytokeratin (CK 20) on floating, thick cutaneous samples (80 to 100 microm), was used. After acquisition of serial optical planes by CSLM, reconstruction was performed with 3-D reconstruction software tools. Merkel cells were clearly labeled with CK 20, whereas nerve components were only NF 200 reactive. The cells, localized on the basal lamina of the epidermis, were usually arranged in clusters of five to eight cells. Each cell was connected to a nerve process ramification originating from a unique fiber. Quantitative data, compiled from a sample of 25 Merkel complexes, gave a mean cell diameter of 13 +/- 1 microm and a mean nerve fiber size of 3 +/- 1 microm. Surface measurements were done on a single reconstructed cluster with a mean and standard error which only refers to the optical 3-D resolution. It gives a surface of 12 +/- 1 microm2 for the contact zone between cell and nerve fiber and a cluster area of about 500 microm2. The great precision of reconstructed images provides a detailed analysis of spatial relationships between abutting nerve fibers and Merkel cells. Data interpretation is improved with complementary ultrastructural and physiological studies results, and this allows an accurate investigation of cutaneous sensory endings.

Intracavernous carotid artery aneurysms: The possible importance of angiographic dural waisting. A case report

Cavernous carotid aneurysms are generally benign entities. Certain indications exist for their treatment, however, including transient ischemic events, subarachnoid hemorrhage or risk of subarachnoid hemorrhage, epistaxis or its risk, ophthalmoplegia, pain, and progressive visual loss. We feel certain angiographic features may indicate a greater likelihood that cavernous carotid aneurysms extend into the subarachnoid space, thus making their rupture a life-threatening event. A case report of an intracavernous carotid aneurysm, which at surgery extended into the subarachnoid space, is described. In this particular case, deformation of the aneurysm (waisting) as seen at angiography was in retrospect an indication that the cavernous carotid aneurysm extended into the subarachnoid space, either through the dural ring or through the eroded dural roof of the cavernous sinus. This finding was verified at surgery when the lesion was explored and trapped. Angiographic waisting of a cavernous carotid aneurysm may indicate that the aneurysm extends into the subarachnoid space. Such extension means that rupture would be a life-threatening event. While deformation of the aneurysm may be secondary to compression against the optic nerve or anterior clinoid process with an intact layer of dura overlying the aneurysm, the neurosurgeon confronted with such findings should analyze such lesions carefully and consider surgical exploration.

GDNF slows loss of motoneurons but not axonal degeneration or premature death of pmn/pmn mice

Glial cell line-derived neurotrophic factor (GDNF), a member of the TG F-beta superfamily, has been shown to be a highly potent neurotrophic factor that enhances survival of various neuronal cell types including motoneurons. To assess its therapeutic potential in treating neurodegenerative diseases such as amyotrophic lateral sclerosis, we treated mutant mice displaying motoneuron degeneration (progressive motor neuropathy; pmn) with encapsulated GDNF-secreting cells. Effects of GDNF treatment on pmn/pmn mice were compared with previous results obtained with ciliary neurotrophic factor (CNTF) [Sagot Y, Tan SA, Baetge E, Schmalbruch H, Kato AC, Aebischer P (1995) Eur J Neurosci 7:1313-1322]. In contrast to CNTF, GDNF did not increase the lifespan of pmn/pmn mice. However, GDNF significantly reduced the loss of facial motoneurons by 50%, a value similar to what was observed when CNTF was administered to the pmn/pmn mice. Surprisingly, myelinated axon counts revealed that GDNF had no effect on nerve degeneration. Therefore, despite its potential in rescuing motoneuron cell bodies, the inability of GDNF to prevent nerve degeneration in pmn/pmn mice suggests that its usefulness in the treatment of motor neuron diseases may be restricted to cotreatment with other factors that act on the nerve process.

Middle Ear Anomalies Induced by Hypertriazene Administration in the Mouse

The middle ear is derived from various embryonic tissues. Many experiments using teratogens have been performed, employing the difference of each tissue's sensitivity to the teratogen and the tissue's critical time of development. Triazene, a foliate metabolism antagonist, produced anomalies in fetuses that resembled those associated with thalidomide in humans, the so-called the first and second branchial syndrome. In our experiment, we administrated 3,3-dimethyl-1-phenyltriazene, an inductor of triazene, to pregnant mice at 7 to 14 days of gestation resulting in unique fetal anomalies. We examined the development of the stapes, stapedial artery, facial nerve, and oval window using an optical microscopic and three-dimensional reconstruction. Middle ear and facial nerve anomalies in mice depend on the gestation day when triazene is administrated. The stapedial artery, oval window, facial nerve (horizontal segment), stapes footplate, and styloid process are affected on the 9th to 11th administration day, the annular stapedialis on the 10th to 11th day, and the malleus and incus on the 9th to 11th day. The use of the Vox View/Mac, allowed us to create three-dimensional pictures from two-dimensional slides providing an improved understanding of the relationships between anatomical structures.