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Transection
Kinds of Transection Selected AbstractsDonor Harvesting: A New Approach to Minimize Transection of Hair FolliclesDERMATOLOGIC SURGERY, Issue 4 2000Damkerng Pathomvanich MD Background. There are several methods for harvesting donor hairs, including punch excision, single-bladed knife excision, and multibladed knife excision. All of these procedures are blind and thus result in transection of hair follicles. Transection of hair follicles during harvesting results in fewer follicles being available for transplantation, detrimentally affecting the final cosmetic result. Objective. To explore a new method of donor hair harvesting called "donor dissecting." This new procedure is an open technique because hair follicles are directly visualized during the harvesting process. Methods. The technique of donor dissecting utilizes a #15 scalpel blade to excise the donor hair ellipse from the occiput while maintaining meticulous hemostasis. This enables individual hair follicles to be visualized and protected from transection during the harvesting process. Once the donor ellipse is harvested, it is then further divided into individual mini- and micrografts using direct visualization of individual follicles to again prevent transection. Results. The technique of donor dissecting was utilized in 50 consecutive hair transplant patients. Utilizing this new technique, only 1.9% of hair follicles in the donor ellipse were transected during the harvesting process. The dissection of the donor ellipse 1.2% follicles being transected in the graft cutting process. Combining the donor dissection technique with dissection of the individual grafts, we were able to transect 1.59% of hair follicles harvested for transplantation. Conclusion. The technique of donor dissection minimizes the transection of hair follicles in the donor hair harvesting phase of hair transplantation. This technique is superior to the blind methods of donor harvesting which have been plagued by the problem of hair follicle transection. [source] Glutamate drives the touch response through a rostral loop in the spinal cord of zebrafish embryosDEVELOPMENTAL NEUROBIOLOGY, Issue 12 2009Thomas Pietri Abstract Characterizing connectivity in the spinal cord of zebrafish embryos is not only prerequisite to understanding the development of locomotion, but is also necessary for maximizing the potential of genetic studies of circuit formation in this model system. During their first day of development, zebrafish embryos show two simple motor behaviors. First, they coil their trunks spontaneously, and a few hours later they start responding to touch with contralateral coils. These behaviors are contemporaneous until spontaneous coils become infrequent by 30 h. Glutamatergic neurons are distributed throughout the embryonic spinal cord, but their contribution to these early motor behaviors in immature zebrafish is still unclear. We demonstrate that the kinetics of spontaneous coiling and touch-evoked responses show distinct developmental time courses and that the touch response is dependent on AMPA-type glutamate receptor activation. Transection experiments suggest that the circuits required for touch-evoked responses are confined to the spinal cord and that only the most rostral part of the spinal cord is sufficient for triggering the full response. This rostral sensory connection is presumably established via CoPA interneurons, as they project to the rostral spinal cord. Electrophysiological analysis demonstrates that these neurons receive short latency AMPA-type glutamatergic inputs in response to ipsilateral tactile stimuli. We conclude that touch responses in early embryonic zebrafish arise only after glutamatergic synapses connect sensory neurons and interneurons to the contralateral motor network via a rostral loop. This helps define an elementary circuit that is modified by the addition of sensory inputs, resulting in behavioral transformation. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009 [source] Endoscopic Injection Sclerotherapy for the Treatment of Recurrent Esophageal Varices after Esophageal TransectionDIGESTIVE ENDOSCOPY, Issue 3 2002Hiroshi Yoshida Background: ,We examined the hemodynamic changes associated with recurrent esophageal varices after esophageal transection (ET) and evaluated the effectiveness of endoscopic injection sclerotherapy (EIS) as the treatment for these varices. Methods: ,Nineteen patients with recurrent esophageal varices after ET were treated by EIS. Endoscopic varicealography during injection sclerotherapy, following oral blockage of flow by a balloon, identified three patterns: (i) type 1: common type, continuous filling by the feeder vessel of the varix; (ii) type 2: retrograde-disappearing type, confirmed hepatofugal flow; and (iii) type 3: immediate washout type, immediate washout of contrast medium. Results: ,Angiography revealed that the hepatofugal feeder vessel was the right gastric vein in all cases. Fourteen patients (73.7%) were classified as type 1, 4 patients (21.1%) as type 2, and 1 patient (5.3%) as type 3. Fewer treatment sessions were required in type 1 than in type 2 (P < 0.005). Recurrent varices were completely eradicated in all patients except the patient with type 3 disease. Cumulative re-recurrence rates at 5 and 10 years were similar for types 1 and 2 (28.6 and 71.4%vs 25 and 25%, respectively). The cumulative survival rates after EIS at 5 and 10 years were also similar for types 1 and 2 (77.1 and 66.1%vs 66.7 and 66.7%). Conclusion: ,Endoscopic injection sclerotherapy is an effective treatment for recurrent esophageal varices after ET, except in type 3 disease. Our classification based on endoscopic varicealography during injection sclerotherapy provides knowledge of blood flow within the varices that helps to inform the treatment strategy. [source] Transection of the sciatic nerve and reinnervation in adult rats: muscle and endplate morphologyEQUINE VETERINARY JOURNAL, Issue S33 2001J. IJKEMA-PAASSEN Summary The functional recovery after peripheral nerve lesions is generally poor. We studied whether changes in muscles after reinnervation might explain such disappointing results. The functional recovery after peripheral nerve lesions is generally poor. Changes in muscle morphology and neuromuscular innervation might partly explain this lack of compensation. In order to test this hypothesis, we studied muscular differentiation in the soleus, gastrocnemius and tibialis anterior muscles at 7, 15 and 21 weeks after a sciatic nerve lesion in adult rats. In the gastrocnemius and tibialis muscles the percentages of type II muscles fibres were decreased at 7 and 15 weeks but at 21 weeks they again approached normal values. The soleus muscle, however, was permanently decreased in size and this muscle, in contrast to the normal soleus muscle, contained mainly type II fibres. The morphology of the endplates showed distinct stages of degeneration and reinnervation. Two weeks after denervation, in rats in which reinnervation was prevented, all 3 muscles contained considerable numbers of morphologically abnormal endplates and, after 7 weeks, no endplates were detected. During reinnervation, endplates showing signs of acetylcholinesterase activity were observed in all 3 muscles from 7 weeks. At later ages a shift towards morphologically normal endplates occurred, but complete recovery was not observed. Endplates in all 3 muscles were polyneurally innervated at 7 weeks. Although these percentages decreased over age, polyneural innervation was still present at 21 weeks. We conclude that the changes in the distribution of fibre types, abnormal endplate morphology and polyneural innervation may in part explain the poor functional recovery after peripheral nerve lesions. [source] In vitro proliferation of axotomized rat facial nucleus-derived activated microglia in an autocrine fashionJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006Kazuyuki Nakajima Abstract Transection of rat adult facial nerve leads to an increase in the number of activated microglia in the facial nucleus (FN), with a peak in proliferation 3 days after transection. To investigate the characteristics of these activated microglia, we isolated the cells with high purity from axotomized FN (axFN) 3 days after transection according to the previously reported procedure for explant culture. The isolated microglia exhibited immunocytochemical properties similar to those in vivo, and their numbers increased approximately five- to sevenfold over a period of 10 days without the addition of any mitogens, suggesting that self-reproduction was occurring. Actually, the microglia actively incorporated bromodeoxyuridine (BrdU) and strongly expressed an S-phase-specific protein marker, proliferating cell nuclear antigen (PCNA). To examine the mechanism underlying this proliferation, the expression of the mitogens and specific receptors of the microglia were analyzed in conditioned medium (CM) and cells. Macrophage-colony stimulating factor (M-CSF) and granulocyte macrophage-CSF (GM-CSF) were detected in the CM as well as in the cells. Their specific receptor proteins, c-Fms and GMCSFR,, were also detected in the cell homogenate. These proliferating microglia were not found to produce deleterious factors for neurons. In summary, the microglia isolated from the axFN were found to be proliferative in an autocrine fashion and to have some cellular properties in common with those observed in vivo. © 2006 Wiley-Liss, Inc. [source] VGLUT1 and VGLUT2 innervation in autonomic regions of intact and transected rat spinal cordTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2007Ida J. Llewellyn-Smith Abstract Fast excitatory neurotransmission to sympathetic and parasympathetic preganglionic neurons (SPN and PPN) is glutamatergic. To characterize this innervation in spinal autonomic regions, we localized immunoreactivity for vesicular glutamate transporters (VGLUTs) 1 and 2 in intact cords and after upper thoracic complete transections. Preganglionic neurons were retrogradely labeled by intraperitoneal Fluoro-Gold or with cholera toxin B (CTB) from superior cervical, celiac, or major pelvic ganglia or adrenal medulla. Glutamatergic somata were localized with in situ hybridization for VGLUT mRNA. In intact cords, all autonomic areas contained abundant VGLUT2-immunoreactive axons and synapses. CTB-immunoreactive SPN and PPN received many close appositions from VGLUT2-immunoreactive axons. VGLUT2-immunoreactive synapses occurred on Fluoro-Gold-labeled SPN. Somata with VGLUT2 mRNA occurred throughout the spinal gray matter. VGLUT2 immunoreactivity was not noticeably affected caudal to a transection. In contrast, in intact cords, VGLUT1-immunoreactive axons were sparse in the intermediolateral cell column (IML) and lumbosacral parasympathetic nucleus but moderately dense above the central canal. VGLUT1-immunoreactive close appositions were rare on SPN in the IML and the central autonomic area and on PPN. Transection reduced the density of VGLUT1-immunoreactive axons in sympathetic subnuclei but increased their density in the parasympathetic nucleus. Neuronal cell bodies with VGLUT1 mRNA occurred only in Clarke's column. These data indicate that SPN and PPN are densely innervated by VGLUT2-immunoreactive axons, some of which arise from spinal neurons. In contrast, the VGLUT1-immunoreactive innervation of spinal preganglionic neurons is sparse, and some may arise from supraspinal sources. Increased VGLUT1 immunoreactivity after transection may correlate with increased glutamatergic transmission to PPN. J. Comp. Neurol. 503:741,767, 2007. © 2007 Wiley-Liss, Inc. [source] Peptide YY administration into the posterior hypothalamic nucleus of the rat evokes cardiovascular changes by non-adrenergic, non-cholinergic mechanismsAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 2 2005J. R. Martin Summary 1 Microinjection of peptide YY (PYY) (0.23,2.3 nmol) into the posterior hypothalamic nucleus (PHN) of conscious rats evokes a dose-dependent pressor response and a bradycardia. 2 The increase in mean arterial pressure evoked by 2.3 nmol of PYY was not blocked by intravenous pretreatment with: (i) the nicotinic ganglionic receptor antagonist pentolinium (PENT, 10 mg kg,1) alone, or in combination with the muscarinic receptor antagonist methylatropine (MeATR, 1 mg kg,1); (ii) the ,1 -adrenoceptor antagonist prazosin (PRAZ, 0.2 mg kg,1); (iii) the V1 -vasopressin receptor antagonist [d(CH2)5Tyr(Me)]AVP (AVPX, 20 ,g kg,1); (iv) the combination of AVPX, PENT and MeATR; (v) the combination of PRAZ, AVPX, PENT, MeATR, and the ,2 -adrenoceptor antagonist yohimbine (0.3 mg kg,1); or (vi) the angiotensin II type 1 receptor antagonist ZD 7155 (1 mg kg,1). 3 Adrenal demedullation inhibited the PYY-evoked responses of drug-naïve rats, and rats pretreated with the combination of PENT, MeATR and AVPX. 4 Transection of the splanchnic nerve innervating the adrenal medullae attenuated the bradycardia, as did ZD 7155, but not the PYY-evoked pressor response. 5 Systemic pretreatment of rats with the neuropeptide Y1 receptor antagonist BIBP 3226 (1 mg kg,1) blocked the PYY-evoked cardiovascular changes, but not those evoked by microinjection of carbachol (5.5 nmol) into the PHN. 6 These results suggest that the cardiovascular changes evoked from the PHN by PYY requires the presence of the adrenal medullae, which are stimulated by: (i) a hormone to release an NPY-like substance that evokes the pressor response, and (ii) the splanchnic nerve to evoke the release of a substance that results in the bradycardia. [source] In Vivo Follicular Unit Multiplication: Is It Possible to Harvest an Unlimited Donor Supply?DERMATOLOGIC SURGERY, Issue 11 2006ERGIN ER MD BACKGROUND Follicular unit extraction is a process of removing one follicular unit at a time from the donor region. The most important limitation of this surgical procedure is a high transection rate. OBJECTIVE In this clinical study, we have transplanted different parts of transected hair follicle by harvesting with the follicular unit extraction technique (FUE) in five male patients. MATERIALS AND METHODS In each patient, three boxes of 1 cm2 are marked at both donor and recipient sites. The proximal one-third, one-half, and two-thirds of 15 hair follicles are extracted from each defined box and transplanted in recipient boxes. The density is determined at 12 months after the procedure. RESULTS A mean of 3 (range, 2,4) of the proximal one-third, 4.4 (range, 2,6) of the proximal one-half, and 6.2 (range, 5,8) of the proximal two-thirds of the transplanted follicles were observed as fully grown after 1 year. At the donor site, the regrowth rate was a mean of 12.6 (range, 10,14) of the proximal one-third, 10.2 (range, 8,13) of the proximal one-half, and 8 (range, 7,12) of the proximal two-thirds, respectively. CONCLUSION The survival rate of the transected hair follicles is directly related to the level of transection. Even the transected parts, however, can survive at the recipient site; the growth rate is not satisfactory and they are thinner than the original follicles. We therefore recommend that the surgeon not transplant the sectioned parts and be careful with the patients whose transection rate is high during FUE procedures. [source] The Corset Platysma Repair: A Technique RevisitedDERMATOLOGIC SURGERY, Issue 3 2002Carolyn I. Jacob MD background. Platysma banding along with excess submental adipose tissue and sagging skin can lead to an aged appearance. Several methods for improving neck and submental contours exist, including neck liposuction, bilateral platysma plication, midline platysma plication with transection of distal fibers, necklift with skin excision, and botulinum toxin injection for platysma relaxation. With the current interest in minimally invasive procedures, surgeons and patients are searching for techniques that produce maximal improvement with minimal intervention. objective. To present a modified technique for maximizing neck contouring, discuss possible complications of the procedure, and describe appropriate candidates for the corset platysmaplasty. methods. We performed a retrospective analysis of 10 consecutive patients who underwent neck liposuction with concomitant corset platysmaplasty at our institution. results. All 10 patients achieved good to excellent submental and jawline contouring, determined by both physician and patient assessment, with no visible platysma banding at 6 months follow-up. No major complications were noted. conclusion. Use of corset platysmaplasty is a safe and effective method for neck rejuvenation. This variation of platysmaplasty can be used in conjunction with neck liposuction to maximize jawline and neck contour enhancement. [source] Donor Harvesting: A New Approach to Minimize Transection of Hair FolliclesDERMATOLOGIC SURGERY, Issue 4 2000Damkerng Pathomvanich MD Background. There are several methods for harvesting donor hairs, including punch excision, single-bladed knife excision, and multibladed knife excision. All of these procedures are blind and thus result in transection of hair follicles. Transection of hair follicles during harvesting results in fewer follicles being available for transplantation, detrimentally affecting the final cosmetic result. Objective. To explore a new method of donor hair harvesting called "donor dissecting." This new procedure is an open technique because hair follicles are directly visualized during the harvesting process. Methods. The technique of donor dissecting utilizes a #15 scalpel blade to excise the donor hair ellipse from the occiput while maintaining meticulous hemostasis. This enables individual hair follicles to be visualized and protected from transection during the harvesting process. Once the donor ellipse is harvested, it is then further divided into individual mini- and micrografts using direct visualization of individual follicles to again prevent transection. Results. The technique of donor dissecting was utilized in 50 consecutive hair transplant patients. Utilizing this new technique, only 1.9% of hair follicles in the donor ellipse were transected during the harvesting process. The dissection of the donor ellipse 1.2% follicles being transected in the graft cutting process. Combining the donor dissection technique with dissection of the individual grafts, we were able to transect 1.59% of hair follicles harvested for transplantation. Conclusion. The technique of donor dissection minimizes the transection of hair follicles in the donor hair harvesting phase of hair transplantation. This technique is superior to the blind methods of donor harvesting which have been plagued by the problem of hair follicle transection. [source] Distribution of neurotrophin-3 during the ontogeny and regeneration of the lizard (Gallotia galloti) visual systemDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2008E. Santos Abstract We have previously described the spontaneous regeneration of retinal ganglion cell axons after optic nerve (ON) transection in the adult Gallotia galloti. As neurotrophin-3 (NT-3) is involved in neuronal differentiation, survival and synaptic plasticity, we performed a comparative immunohistochemical study of NT-3 during the ontogeny and regeneration (after 0.5, 1, 3, 6, 9, and 12 months postlesion) of the lizard visual system to reveal its distribution and changes during these events. For characterization of NT-3+ cells, we performed double labelings using the neuronal markers HuC-D, Pax6 and parvalbumin (Parv), the microglial marker tomato lectin or Lycopersicon esculentum agglutinin (LEA), and the astroglial markers vimentin (Vim) and glial fibrillary acidic protein (GFAP). Subpopulations of retinal and tectal neurons were NT-3+ from early embryonic stages to adulthood. Nerve fibers within the retinal nerve fiber layer, both plexiform layers and the retinorecipient layers in the optic tectum (OT) were also stained. In addition, NT-3+/GFAP+ and NT-3+/Vim+ astrocytes were detected in the ON, chiasm and optic tract in postnatal and adult lizards. At 1 month postlesion, abundant NT-3+/GFAP+ astrocytes and NT-3,/LEA+ microglia/macrophages were stained in the lesioned ON, whereas NT-3 became downregulated in the experimental retina and OT. Interestingly, at 9 and 12 months postlesion, the staining in the experimental retina resembled that in control animals, whereas bundles of putative regrown fibers showed a disorganized staining pattern in the OT. Altogether, we demonstrate that NT-3 is widely distributed in the lizard visual system and its changes after ON transection might be permissive for the successful axonal regrowth. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008 [source] Survival of mammalian B104 cells following neurite transection at different locations depends on somal Ca2+ concentrationDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2004Soonmoon Yoo Abstract We report that cell survival after neurite transection in a mammalian neuronal model (cultured B104 cells) critically depends on somal [Ca2+]i, a novel result that reconciles separate long-standing observations that somal survival decreases with more-proximal axonal transections and that increased somal Ca2+ is cytotoxic. Using fluorescence microscopy, we demonstrate that extracellular Ca2+ at the site of plasmalemmal transection is necessary to form a plasmalemmal barrier, and that other divalent ions (Ba2+, Mg2+) do not play a major role. We also show that extracellular Ca2+, rather than injury per se, initiates the formation of a plasmalemmal barrier and that a transient increase in somal [Ca2+]i significantly decreases the percentage of cells that survive neurite transection. Furthermore, we show that the increased somal [Ca2+]i and decreased cell survival following proximal transections are not due to less frequent or slower plasmalemmal sealing or Ca2+ entry through plasmalemmal Na+ and Ca2+ channels. Rather, the increased somal [Ca2+]i and lethality of proximal neurite injuries may be due to the decreased path length/increased diameter for Ca2+ entering the transection site to reach the soma. A ryanodine block of Ca2+ release from internal stores before transection has no effect on cell survival; however, a ryanodine- or thapsigargin-induced buildup of somal [Ca2+]i before transection markedly reduces cell survival, suggesting a minor involvement of Ca2+ -induced release from internal stores. Finally, we show that cell survival following proximal injuries can be enhanced by increasing intracellular Ca2+ buffering capacity with BAPTA to prevent the increase in somal [Ca2+]i. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 137,153, 2004 [source] Initial stages of neural regeneration in Helisoma trivolvis are dependent upon PLA2 activityDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2003Matthew S. Geddis Abstract Neuronal regeneration after damage to an axon tract requires the rapid sealing of the injured plasma membrane and the subsequent formation of growth cones that can lead regenerating processes to their appropriate target. Membrane sealing and growth cone formation are Ca2+ -dependent processes, but the signaling pathways activated by Ca2+ to bring about these effects remain poorly understood. An in vitro injury model was employed in which neurites from identified snail neurons (Helisoma trivolvis) were transected with a glass microknife, and the formation of new growth cones from the distal portions of transected neurites was recorded at defined times after transection. This study presents three main results. First, phospholipase A2 (PLA2), a calcium-activated enzyme, is necessary for membrane sealing in vitro. Second, PLA2 activity is also required for the formation of a new growth cone after the membrane has sealed successfully. Thus, PLA2 plays a dual role by affecting both growth cone formation and membrane sealing. Third, the injury-induced activation of PLA2 by Ca2+ controls growth cone formation through the production of leukotrienes, secondary metabolites of PLA2 activity. Taken together, these results suggest that the injury-induced Ca2+ influx acts via PLA2 and leukotriene production to assure growth cone formation. These findings indicate that events that cause an inhibition of PLA2 or lipoxygenases, enzymes that produce leukotrienes, could result in the inability of neurites to regenerate. © 2003 Wiley Periodicals, Inc. J Neurobiol 54: 555,565, 2003 [source] Maternal anesthesia via isoflurane or ether differentially affects pre-and postnatal behavior in rat offspringDEVELOPMENTAL PSYCHOBIOLOGY, Issue 7 2007April E. Ronca Abstract Our understanding of prenatal behavior has been significantly advanced by techniques for direct observation and manipulation of unanesthetized, behaving rodent fetuses with intact umbilical connections to the mother. These techniques involve brief administration of an inhalant anesthesic, enabling spinal transection of the rat or mouse dam, after which procedures can continue with unanesthetized dams and fetuses. Because anesthetics administered to the mother can cross the placental barrier, it is possible that fetuses are anesthetized to varying degrees. We compared in perinatal rats the effects of prenatal maternal exposure to two inhalant anesthetics: ether and isoflurane. Fewer spontaneous fetal movements and first postpartum nipple attachments were observed following maternal exposure to ether as compared to isoflurane. Neonatal breathing frequencies and oxygenation did not account for group differences in nipple attachment. Our results provide evidence that the particular inhalant anesthetic employed in prenatal manipulation studies determines frequencies of perinatal behavior. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 675,684, 2007. [source] Endoscopic Injection Sclerotherapy for the Treatment of Recurrent Esophageal Varices after Esophageal TransectionDIGESTIVE ENDOSCOPY, Issue 3 2002Hiroshi Yoshida Background: ,We examined the hemodynamic changes associated with recurrent esophageal varices after esophageal transection (ET) and evaluated the effectiveness of endoscopic injection sclerotherapy (EIS) as the treatment for these varices. Methods: ,Nineteen patients with recurrent esophageal varices after ET were treated by EIS. Endoscopic varicealography during injection sclerotherapy, following oral blockage of flow by a balloon, identified three patterns: (i) type 1: common type, continuous filling by the feeder vessel of the varix; (ii) type 2: retrograde-disappearing type, confirmed hepatofugal flow; and (iii) type 3: immediate washout type, immediate washout of contrast medium. Results: ,Angiography revealed that the hepatofugal feeder vessel was the right gastric vein in all cases. Fourteen patients (73.7%) were classified as type 1, 4 patients (21.1%) as type 2, and 1 patient (5.3%) as type 3. Fewer treatment sessions were required in type 1 than in type 2 (P < 0.005). Recurrent varices were completely eradicated in all patients except the patient with type 3 disease. Cumulative re-recurrence rates at 5 and 10 years were similar for types 1 and 2 (28.6 and 71.4%vs 25 and 25%, respectively). The cumulative survival rates after EIS at 5 and 10 years were also similar for types 1 and 2 (77.1 and 66.1%vs 66.7 and 66.7%). Conclusion: ,Endoscopic injection sclerotherapy is an effective treatment for recurrent esophageal varices after ET, except in type 3 disease. Our classification based on endoscopic varicealography during injection sclerotherapy provides knowledge of blood flow within the varices that helps to inform the treatment strategy. [source] The Double Jeopardy of Blunt Chest Trauma: A Case Report and ReviewECHOCARDIOGRAPHY, Issue 3 2006Subha L. Varahan M.D. Cardiac injury, specifically valvular rupture, must be considered after blunt chest trauma even in previously healthy patients. Isolated mitral regurgitation (MR) and tricuspid regurgitation (TR) due to blunt chest trauma are rare phenomena. More unique is simultaneous complete papillary muscle rupture of the mitral valve (MV) and tricuspid valve (TV) with only four patients being previously reported in the literature. This case describes a patient with complete transection of the posteromedial papillary muscle of the MV with severe MR and a concomitant flail TV with severe TR following a motor vehicular accident. The importance of transthoracic and transesophageal echocardiography in the early evaluation of patients following blunt chest trauma is also highlighted by this case. [source] Multiple Subpial Transections: The Yale ExperienceEPILEPSIA, Issue 2 2001Lisa P. Mulligan Summary: ,Purpose: Although resection of an epileptogenic region is the mainstay of epilepsy surgery, epileptogenic areas in functionally critical cortex cannot be approached in that manner. Multiple subpial transection (MST) was developed to treat those refractory seizures without causing unacceptable neurologic deficit. We review our experience with this technique. Methods: Twelve patients who underwent MST with or without resection between 1990 and 1998 were retrospectively reviewed with regard to seizure and neurologic outcome, and predictive factors. Results: Five (42%) of 12 patients obtained a significant improvement in seizure frequency, and two other patients had a marked decrease in the severity of their seizures. Resection with MST reduced seizure frequency more, but this was not a significant difference. No predictive factors for outcome were identified. Only one patient sustained any persistent neurologic deficit. Conclusions: In selected patients, MST may be a viable alternative when the epileptogenic focus lies in unresectable cortex. A multicenter study with appreciable patient numbers will be necessary to define predictive factors for success. [source] The Role of Intracranial Electrode Reevaluation in Epilepsy Patients After Failed Initial Invasive MonitoringEPILEPSIA, Issue 5 2000Adrian M. Siegel Summary: Purpose: Intracranial electrode recording often provides localization of the site of seizure onset to allow epilepsy surgery. In patients whose invasive evaluation fails to localize seizure origin, the utility of further invasive monitoring is unknown. This study was undertaken to explore the hypothesis that a second intracranial investigation is selected patients warrants consideration and can lead to successful epilepsy surgery. Methods: A series of 110 consecutive patients with partial epilepsy who had undergone intracranial electrode evaluation (by subdural strip, subdural grid, and/or depth electrodes) between February 1992 and October 1998 was retrospectively analyzed. Of these, failed localization of seizure origin was thought to be due to sampling error in 13 patients. Nine of these 13 patients underwent a second intracranial investigation. Results: Reevaluation with intracranial electrodes resulted in satisfactory seizure-onset localization in seven of nine patients, and these seven had epilepsy surgery. Three frontal, two temporal, and one occipital resection as well as one multiple subpial transection were performed. Six patients have become seizure free, and one was not significantly improved. The mean follow-up is 2.8 years. There was no permanent morbidity. Conclusions: In selected patients in whom invasive monitoring fails to identify the site of seizure origin, reinvestigation with intracranial electrodes can achieve localization of the region of seizure onset and allow successful surgical treatment. [source] Intra-articular stabilisation of the equine cricoarytenoid jointEQUINE VETERINARY JOURNAL, Issue 6 2008J. CHEETHAM Summary Reasons for performing study: The success of laryngoplasty is limited by abduction loss in the early post operative period. Objective: To determine the efficacy of polymethylmethacrylate (PMMA) in stabilising the cricoarytenoid joint (CAJ) and reducing the force on the laryngoplasty suture. Hypothesis: Injection into the cricoarytenoid joint resists the forces produced by physiological laryngeal air flows and pressures thereby reducing the force experienced by the laryngoplasty suture. Methods: Ten cadaver larynges were collected at necropsy and PMMA was injected into one CAJ at selected random. Each larynx was subjected to physiological conditions with with constant (static) or cycling (dynamic) flow. The specimens were tested sequentially in each of 4 conditions: 1) bilateral full abduction (Control 1); 2) transection of the suture on the side without PMMA; 3) bilateral abduction achieved by replacing the suture (Control 2); and 4) cutting the suture on the PMMA side. Tracheal pressure and flow and pressure in the flow chamber were recorded using pressure and flow transducers. The strain experienced by each suture during bilateral abduction (Controls 1 and 2) was measured. Statistical comparison of the 4 conditions was performed using a mixed effect model with Tukey's post hoc test for multiple comparisons. The strain gauge data were analysed by paired comparison of the regression slopes. Results: In the static and dynamic states, tracheal pressure increased and tracheal flow decreased when the suture on the non-cement side was cut (P<0.05). There was no significant difference in any outcome measure between PMMA injected into the CAJ and bilaterally abducted specimens (Controls 1 and 2) for either condition. The rate of increase in strain with increasing translaryngeal pressure was significantly less on the suture with PMMA placed in the CAJ (P = 0.03). Conclusions: These data provide strong evidence that injecting PMMA into the CAJ resists the collapsing effect of physiological airflows and pressures in vitro and reduces the force experienced by the laryngoplasty suture during maximal abduction. Potential relevance: Augmentation of prosthetic laryngoplasty with this technique may reduce arytenoid abduction loss in the early post operative period. [source] Effects of Delaying Fluid Resuscitation on an Injury to the Systemic Arterial VasculatureACADEMIC EMERGENCY MEDICINE, Issue 4 2002James F. Holmes MD Abstract. Objectives: To determine the effects of delaying fluid on the rate of hemorrhage and hemodynamic parameters in an injury involving the arterial system. Methods: Twenty-one adult, anesthetized sheep underwent left anterior thoracotomy and transection of the left internal mammary artery. A chest tube was inserted into the thoracic cavity to provide a continuous measurement of blood loss. The animals were randomly assigned to one of three resuscitation protocols: 1) no fluid resuscitation (NR), 2) standard fluid resuscitation (SR) begun 15 minutes after injury, or 3) delayed fluid resuscitation (DR) begun 30 minutes after injury. All of the animals in the two resuscitation groups received 60 mL/kg of lactated Ringer's solution over 30 minutes. Blood loss and hemodynamic parameters were measured throughout the experiment. Results: Total hemorrhage volume (mean ± SD) at the end of the experiment was significantly lower (p = 0.006) in the NR group (1,499 ± 311 mL) than in the SR group (3,435 ± 721 mL) or the DR group (2,839 ± 1549 mL). Rate of hemorrhage followed changes in mean arterial pressure in all groups. Hemorrhage spontaneously ceased significantly sooner (p = 0.007) in the NR group (21 ± 14 minutes) and the DR group (20 ± 15 minutes) than in the SR group (54 ± 4 minutes). In the DR group, after initial cessation of hemorrhage, hemorrhage recurred in five of six animals (83%) with initiation of fluid resuscitation. Maximum oxygen (O2) delivery in each group after injury was as follows: 101 ± 34 mL O2/kg/min at 45 minutes in the DR group, 51 ± 20 mL O2/kg/min at 30 minutes in the SR group, and 35 ± 8 mL O2/kg/min at 60 minutes in the NR group. Conclusions: Rates of hemorrhage from an arterial injury are related to changes in mean arterial pressure. In this animal model, early aggressive fluid resuscitation in penetrating thoracic trauma exacerbates total hemorrhage volume. Despite resumption of hemorrhage from the site of injury, delaying fluid resuscitation results in the best hemodynamic parameters. [source] Impairment of CaMKII activation and attenuation of neuropathic pain in mice lacking NR2B phosphorylated at Tyr1472EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2010Shinji Matsumura Abstract Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a key mediator of long-term potentiation (LTP), which can be triggered by N -methyl- d -aspartate (NMDA) receptor-mediated Ca2+ influx. We previously demonstrated that Fyn kinase-mediated phosphorylation of NR2B subunits of NMDA receptors at Tyr1472 in the dorsal horn was involved in a neuropathic pain state even 1 week after nerve injury. Here we show that Y1472F-KI mice with a knock-in mutation of the Tyr1472 site to phenylalanine did not exhibit neuropathic pain induced by L5 spinal nerve transection, whereas they did retain normal nociceptive responses and induction of inflammatory pain. Phosphorylation of NR2B at Tyr1472 was only impaired in the spinal cord of Y1472F-KI mice among the major phosphorylation sites. There was no difference in the Ca2+ response to glutamate and sensitivity to NMDA receptor antagonists between naive wild-type and Y1472F-KI mice, and the Ca2+ response to glutamate was attenuated in the Y1472F-KI mice after nerve injury. Autophosphorylation of CaMKII at Thr286 was markedly impaired in Y1472F-KI mice after nerve injury, but there was no difference in phosphorylation of CaMKII at Thr305 or protein kinase C, at Thr674, and activation of neuronal nitric oxide synthase and microglia in the superficial layer of spinal cord between wild-type and Y1472F-KI mice after the operation. These results demonstrate that the attenuation of neuropathic pain is caused by the impaired NMDA receptor-mediated CaMKII signaling in Y1472F-KI mice, and suggest that autophosphorylation of CaMKII at Thr286 plays a central part not only in LTP, but also in persistent neuropathic pain. [source] Developmental neural plasticity and its cognitive benefits: olivocerebellar reinnervation compensates for spatial function in the cerebellumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2007Melina L. Willson Abstract The adult mammalian central nervous system displays limited reinnervation and recovery from trauma. However, during development, post-lesion plasticity may generate alternative paths, thus providing models to investigate reinnervation and repair. After unilateral transection of the neonatal rat olivocerebellar path (pedunculotomy), axons from the remaining inferior olive reinnervate the denervated hemicerebellum. Unfortunately, reinnervation to the cerebellar hemisphere is incomplete; therefore, its capacity to mediate hemispheric function (navigation) is unknown. We studied sensorimotor control and spatial cognition of rats with and without transcommissural reinnervation using simple (bridge and ladder) and complex (wire) locomotion tests and the Morris water maze (hidden, probe and cued paradigms). Although pedunculotomized animals completed locomotory tasks more slowly than controls, all groups performed equally in the cued maze, indicating that lesioned animals could orientate to and reach the platform. In animals pedunculotomized on day 3 (Px3), which develop olivocerebellar reinnervation, final spatial knowledge was as good as controls, although they learned more erratically, failing to retain all information from one day to the next. By contrast, animals pedunculotomized on day 11 (Px11), which do not develop reinnervation, did not learn the task, taking less direct routes and more time to reach the platform than controls. In the probe test, control and Px3, but not Px11, animals swam directly to the remembered location. Furthermore, the amount of transcommissural reinnervation to the denervated hemisphere correlated directly with spatial performance. These results show that transcommissural olivocerebellar reinnervation is associated with spatial learning, i.e. even partial circuit repair confers significant functional benefit. [source] Effect of neurotrophin-3 on reinnervation of the larynx using the phrenic nerve transfer techniqueEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2007Paul J. Kingham Abstract Current techniques for reinnervation of the larynx following recurrent laryngeal nerve (RLN) injury are limited by synkinesis, which prevents functional recovery. Treatment with neurotrophins (NT) may enhance nerve regeneration and encourage more accurate reinnervation. This study presents the results of using the phrenic nerve transfer method, combined with NT-3 treatment, to selectively reinnervate the posterior cricoarytenoid (PCA) abductor muscle in a pig nerve injury model. RLN transection altered the phenotype and morphology of laryngeal muscles. In both the PCA and thyroarytenoid (TA) adductor muscle, fast type myosin heavy chain (MyHC) protein was decreased while slow type MyHC was increased. These changes were accompanied with a significant reduction in muscle fibre diameter. Following nerve repair there was a progressive normalization of MyHC phenotype and increased muscle fibre diameter in the PCA but not the TA muscle. This correlated with enhanced abductor function indicating the phrenic nerve accurately reinnervated the PCA muscle. Treatment with NT-3 significantly enhanced phrenic nerve regeneration but led to only a small increase in the number of reinnervated PCA muscle fibres and minimal effect on abductor muscle phenotype and morphology. Therefore, work exploring other growth factors, either alone or in combination with NT-3, is required. [source] Altered neuronal responses and regulation of neurotrophic proteins in the medial septum following fimbria-fornix transection in CNTF- and leukaemia inhibitory factor-deficient miceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2006Thomas Naumann Abstract Degeneration of axotomized GABAergic septohippocampal neurones has been shown to be enhanced in ciliary neurotrophic factor (CNTF)-deficient mice following fimbria-fornix transection (FFT), indicating a neuroprotective function of endogenous CNTF. Paradoxically, however, the cholinergic population of septohippocampal neurones was more resistant to axotomy in these mutants. As leukaemia inhibitory factor (LIF) has been identified as a potential neuroprotective factor for the cholinergic medial septum (MS) neurones, FFT-induced responses were compared in CNTF,/,, LIF,/, and CNTF/LIF double knockout mice. In CNTF,/, mice, FFT-induced cholinergic degeneration was confirmed to be attenuated as compared with wildtype mice. The expression of both LIF and LIF receptor , was increased in the MS providing a possible explanation for the enhanced neuronal resistance to FFT in these animals. However, ablation of the LIF gene also produced paradoxical effects; following FFT in LIF,/, mice no loss of GABAergic or cholinergic MS neurones was detectable during the first postlesional week, suggesting that other efficient neuroprotective mechanisms are activated in these animals. In fact, enhanced activation of astrocytes, a source of neurotrophic proteins, was indicated by increased up-regulation of glial fibrillary acidic protein and vimentin expression. In addition, mRNA levels for neurotrophin signalling components (e.g. nerve growth factor, p75NTR) were differentially regulated. The positive effect on axotomized cholinergic neurones seen in CNTF,/, and LIF,/, mice as well as the increased up-regulation of astrogliose markers was abolished in CNTF/LIF double knockout animals. Our results indicate that endogenous CNTF and LIF are involved in the regulation of neuronal survival following central nervous system lesion and are integrated into a network of neurotrophic signals that mutually influence their expression and function. [source] Afferent,target interactions during olivocerebellar development: transcommissural reinnervation indicates interdependence of Purkinje cell maturation and climbing fibre synapse eliminationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2005Ann M. Lohof Abstract We have used a model of postlesional reinnervation to observe the interactions between synaptic partners during neosynaptogenesis to determine how the developmental states of the pre- and postsynaptic cells influence circuit maturation. After unilateral transection of the neonatal rat olivocerebellar pathway (pedunculotomy), axons from the remaining ipsilateral inferior olive grow into the denervated hemicerebellum and develop climbing fibre (CF) terminal arbors on Purkinje cells (PCs) at a later stage of development than normal. However, the significance of delayed CF-PC interactions on subsequent circuit maturation remains poorly defined. To examine this question, we recorded CF-induced currents in PCs and analysed PC morphology during the first two postnatal weeks in control animals and following left unilateral inferior cerebellar pedunculotomy on postnatal day (P)3. Our results show that transcommissural olivary axons multiply-reinnervate PCs in the denervated hemisphere over 4 days following pedunculotomy. Each PC received fewer CFs than did age-matched controls and the maximal multi-reinnervation was reached on P7, 2 days later than in controls. Consequently, the onset of CF synapse elimination in reinnervated PCs was delayed, but then proceeded in parallel with controls so that all PCs were monoinnervated by P15. Furthermore, reinnervated PCs had delayed dendritic maturation and subsequent dendritic abnormalities consistent with the role of CF innervation in PC dendritic growth. Thus, within the olivocerebellar system, our data suggest that target neurons depend upon sufficient afferent investment arriving at the correct time for their normal development, and maturation of the target neuron regulates afferent selection and therefore circuit maturation. [source] Binding partners L1 cell adhesion molecule and the ezrin-radixin-moesin (ERM) proteins are involved in development and the regenerative response to injury of hippocampal and cortical neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2004Matilda A. Haas Abstract Regeneration of the adult central nervous system may require recapitulation of developmental events and therefore involve the re-expression of developmentally significant proteins. We have investigated whether the L1 cell adhesion molecule, and its binding partner, the ezrin-radixin-moesin (ERM) proteins are involved in the neuronal regenerative response to injury. Hippocampal and cortical neurons were cultured in vitro on either an L1 substrate or poly-L-lysine, and ERM and other neuronal proteins were localized immunocytochemically both developmentally and following neurite transection of neurons maintained in long-term culture. Activated ERM was localized to growth cones up to 7 days in vitro but relatively mature cultures (21 days in vitro) were devoid of active ERM proteins. However, ERM proteins were localized to the growth cones of sprouting neuronal processes that formed several hours after neurite transection. In addition, the L1 substrate, relative to poly-L-lysine, resulted in significantly longer regenerative neurites, as well as larger growth cones with more filopodia. Furthermore, neurons derived from the cortex formed significantly longer post-injury neurite sprouts at 6 h post-injury than hippocampal derived neurons grown on both substrates. We have demonstrated that L1 and the ERM proteins are involved in the neuronal response to injury, and that neurons derived from the hippocampus and cortex may have different post-injury regenerative neurite sprouting abilities. [source] NGF and GDNF ameliorate the increase in ATF3 expression which occurs in dorsal root ganglion cells in response to peripheral nerve injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2004Sharon Averill Abstract Activating transcription factor-3 (ATF3) is a member of the ATF/CREB transcription factor superfamily and is induced in dorsal root ganglion (DRG) cells after nerve injury. In order to study the regulation of ATF3, we have examined the effect of nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF) on ATF3 expression. In untreated rats, sciatic nerve transection induced ATF3 immunoreactivity in 82% of L4 DRG cells at 14 days after axotomy. Intrathecal delivery of NGF or GDNF for 2 weeks commencing immediately after injury reduced the ATF3 expression to 35 and 23% of DRG cells, respectively. Cell size analysis indicated that NGF had protected a population of mainly small- to medium-sized cells, but that the GDNF had protected a population of both small and large cells. This effect was confirmed by double labelling for P2X3, CGRP and 200 kDa neurofilament, markers for small peptide-poor cells, peptide-rich cells and large cells, respectively. Thus GDNF reduced the percentage of ATF3-immunoreactive P2X3 cells from 70 to 4%, and the percentage of ATF3-immunoreactive neurofilament cells from 63 to 24%. NGF was less effective than GDNF in reducing ATF3 expression in these cell types, but reduced the percentage of ATF3-immunoreactive CGRP cells from 10% to <,1%. These results show that ATF3 expression in specific populations of DRG cells can be modulated by exogenous supplementation of specific trophic factors, and suggest that ATF3 expression may normally be induced by the loss of target-derived NGF and GDNF. [source] Dynamic changes in glypican-1 expression in dorsal root ganglion neurons after peripheral and central axonal injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2004Stefan Bloechlinger Abstract Glypican-1, a glycosyl phosphatidyl inositol (GPI)-anchored heparan sulphate proteoglycan expressed in the developing and mature cells of the central nervous system, acts as a coreceptor for diverse ligands, including slit axonal guidance proteins, fibroblast growth factors and laminin. We have examined its expression in primary sensory dorsal root ganglion (DRG) neurons and spinal cord after axonal injury. In noninjured rats, glypican-1 mRNA and protein are constitutively expressed at low levels in lumbar DRGs. Sciatic nerve transection results in a two-fold increase in mRNA and protein expression. High glypican-1 expression persists until the injured axons reinnervate their peripheral targets, as in the case of a crushed nerve. Injury to the central axons of DRG neurons by either a dorsal column injury or a dorsal root transection also up-regulates glypican-1, a feature that differs from most DRG axonal injury-induced genes, whose regulation changes only after peripheral and not central axonal injury. After axonal injury, the cellular localization of glypican-1 changes from a nuclear pattern restricted to neurons in noninjured DRGs, to the cytoplasm and membrane of injured neurons, as well as neighbouring non-neuronal cells. Sciatic nerve transection also leads to an accumulation of glypican-1 in the proximal nerve segment of injured axons. Glypican-1 is coexpressed with robo 2 and its up-regulation after axonal injury may contribute to an altered sensitivity to axonal growth or guidance cues. [source] Post-lesion transcommissural growth of olivary climbing fibres creates functional synaptic microzonesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2003Izumi Sugihara Abstract In the adult mammalian central nervous system, reinnervation and recovery from trauma is limited. During development, however, postlesion plasticity may generate alternate paths, providing models to investigate reinnervating axon,target interactions. After unilateral transection of the neonatal rat olivocerebellar path, axons from the ipsilateral inferior olive grow into the denervated hemicerebellum and develop climbing fibre (CF)-like arbors on Purkinje cells (PCs). However, the synaptic function and extent of PC reinnervation remain unknown. In adult rats pedunculotomized on postnatal day 3 the morphological and electrophysiological properties of reinnervating olivocerebellar axons were studied, using axonal reconstruction and patch-clamp PC recording of CF-induced synaptic currents. Reinnervated PCs displayed normal CF currents, and the frequency of PC reinnervation decreased with increasing laterality. Reinnervating CF arbors were predominantly normal but 6% branched within the molecular layer forming smaller secondary arbors. CFs arose from transcommissural olivary axons, which branched extensively near their target PCs to produce on average 36 CFs, which is six times more than normal. Axons terminating in the hemisphere developed more CFs than those terminating in the vermis. However, the precise parasagittal microzone organization was preserved. Transcommissural axons also branched, although to a lesser extent, to the deep cerebellar nuclei and terminated in a distribution indicative of the olivo-cortico-nuclear circuit. These results show that reinnervating olivocerebellar axons are highly plastic in the cerebellum, compensating anatomically and functionally for early postnatal denervation, and that this reparation obeys precise topographic constraints although axonal plasticity is modified by target (PC or deep nuclear neurons) interactions. [source] Decreased iNOS synthesis mediates dexamethasone-induced protection of neurons from inflammatory injury in vitroEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2003Sabine Golde Abstract Brain inflammation is accompanied by transection of axons and death of neurons in the acute lesions of multiple sclerosis. We explored mechanisms of inflammatory damage to neurons in vitro using cocultures of rat embryonal cortical neurons with microglia activated by interferon-gamma (IFN,) and lipopolysaccharide (LPS). Previously, we have demonstrated that microglia are highly toxic to neurons and that nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS) is necessary and sufficient to mediate this toxicity. Here, we show that addition of dexamethasone (1 µM) to activated cocultures provides effective neuroprotection. We demonstrate that dexamethasone down-regulates NO production of primary microglia by ,,50% and reduces steady-state iNOS protein and mRNA expression by ,,70%. These changes were reversed by the glucocorticoid receptor blocker RU-486. Furthermore, we analysed the stability of iNOS protein and show that whilst inhibitors of the proteasome blocked iNOS degradation they did not reverse the dexamethasone effect. Our results indicate that the main mechanism of corticosteroid activity on iNOS is reduction in protein synthesis, not destabilization as previously suggested. [source] | ||||||||||||||||||||||||||||||||||