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Stumps
Kinds of Stumps Selected AbstractsCanopy recovery after drought dieback in holm-oak Mediterranean forests of Catalonia (NE Spain)GLOBAL CHANGE BIOLOGY, Issue 12 2004Francisco Lloret Abstract Climate change is likely to produce more frequent and longer droughts in the Mediterranean region, like that of 1994, which produced important changes in the Quercus ilex forests, with up to 76% of the trees showing complete canopy dieback. At the landscape level, a mosaic of responses to the drought was observed, linked to the distribution of lithological substrates. Damage to the dominant tree species (Q. ilex) and the most common understorey shrub (Erica arborea) was more noticeable on the compact substrates (breccia) than on the fissured ones (schist). This result was consistent with observations documenting deeper root penetration in schist than in breccia materials, allowing the plants growing on fissured substrates to use water from deeper soil levels. Smaller plants were more vulnerable to drought than larger plants in the trees, but not in the shrubs. Overall, Q. ilex was more affected than E. arborea. The resilience of the system was evaluated from the canopy recovery 1 year after the episode. Stump and crown resprouting was fairly extensive, but the damage pattern in relation to substrate, plant size, and species remained similar. The effect of recurrent drought episodes was studied on vegetation patches of Q. ilex located on mountain slopes and surrounded by bare rock. We observed that plants that resprouted weakly after a previous drought in 1985 were more likely to die or to produce poor regeneration in 1995 than plants that had resprouted vigorously. Vegetation patches located on the lower part of the slope were also less damaged than patches situated uphill. The study provides evidence of relevant changes in forest canopy as a consequence of extreme climate events. The distribution of this effect across the landscape is mediated by lithological substrate, causing patchy patterns. The results also support the hypothesis that recurrent droughts can produce a progressive loss of resilience, by depleting the ability of surviving plants to regenerate. [source] Effect of time of year on the development of immature stages of the Large Pine Weevil (Hylobius abietis L.) in stumps of Sitka spruce (Picea sitchensis Carr.) and influence of felling date on their growth, density and distributionJOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2004R. Moore Abstract:, The time of year and time of felling of a commercial stand of Sitka spruce (Picea sitchensis Carr.) were both shown to influence the spatial distribution and development of the large pine weevil, Hylobius abietis (L). Stump and root systems were excavated over a 5-month period in 1997, between 18 and 27 months after felling, and all immature H. abietis removed. On a site with a 6-month spread of felling dates in 1995, mean larval weights in 1997 were higher in stumps from earlier fellings, but H. abietis numbers were higher in stumps from later fellings. This appeared to be due to the continued presence of older, heavier larvae, laid as eggs in 1995, in stumps from earlier fellings, combined with a greater concentration of oviposition having occurred in 1996 in the fresher stumps of later fellings. Pupae were first found in excavated stumps on 12 June 1997 and adults on 29 July 1997. Emergence of the ,new generation' of adult weevils commenced on 7 August 1997. On average, 25% of H. abietis adults emerged in autumn 1997, 41% in 1998 and 34% in 1999. First emergence (1997) was proportionally higher in the areas felled earlier in 1995 than those felled later that year. However, the opposite was found for third emergence (1999) where emergence was greater for stumps created later in 1995. Larger stumps contained greater densities of H. abietis. Total ,potential' emergence was estimated to be between 46400 and 170825 H. abietis/ha. However, emergence traps indicated that only 40,80% managed to complete their development and emerge successfully. It is suggested that within-season felling date may be one of the most important factors affecting larval development, distribution and abundance; as well as subsequent damage levels associated with adult feeding. Consequently, knowledge of felling date could be crucial to developing methods of integrated forest management for this major forest pest. [source] Obama on the Stump: Features and Determinants of a Rhetorical ApproachPRESIDENTIAL STUDIES QUARTERLY, Issue 3 2010KEVIN COE From the moment Barack Obama entered the national political scene in 2004, his formidable rhetorical skills were a central component of his public persona and his political success. Not surprisingly, a growing body of research has examined Obama's rhetorical techniques. Thus far, however, these studies have consisted almost entirely of qualitative analyses of single speeches, making it difficult to generalize about the broader features of Obama's rhetorical approach and impossible to understand the determinants of his rhetorical choices. This study fills these gaps in the literature by systematically tracking Obama's rhetoric over the course of campaign 2008 and testing competing explanations for the variation that occurs during this period. Using a unique computer-assisted content analysis procedure that draws coding categories directly from the more than 11,500 distinct words that Obama used during his campaign, the authors analyze 183 speeches and debates from his announcement of candidacy in February 2007 to his victory speech in November 2008. Obama's campaign rhetoric varied by speaking context, geography, and poll position, indicating a twofold rhetorical approach of emphasizing policy and thematic appeals while downplaying more contentious issues. [source] Ultrastructural changes in skeletal muscle of the tail of the lizard Hemidactylus mabouia immediately following autotomyACTA ZOOLOGICA, Issue 4 2010Tomaz Henrique Araújo Abstract Araújo, T.H., Faria, F.P., Katchburian, E. and Freymüller, E. (2009). Ultrastructural changes in skeletal muscle of the tail of the lizard Hemidactylus mabouia immediately following autotomy. ,Acta Zoologica (Stockholm) 91: 440,446. Although autotomy and subsequent regeneration of lizard tails has been extensively studied, there is little information available on ultrastructural changes that occur to the muscle fibers at the site of severance. Thus, in the present study, we examine the ultrastructure of the musculature of the remaining tail stump of the lizard Hemidactylus mabouia immediately after autotomy. Our results show that exposed portions of the skeletal muscle fibers of the stump that are unprotected by connective tissue bulge to produce large mushroom-like protrusions. These exposed portions show abnormal structure but suffer no leakage of cytoplasmic contents. Many small and large vesicular structures appeared between myofibrils in the interface at this disarranged region (distal) and the other portion of the fibers that remain unchanged (proximal). These vesicles coalesce, creating a gap that leads to the release of the mushroom-like protrusion. So, our results showed that after the macroscopic act of autotomy the muscular fibers release part of the sarcoplasm as if a second and microscopic set of autotomic events takes place immediately following the macroscopic act of autotomy. Presumably these changes pave the way for the formation of a blastema and the beginning of regeneration. [source] Ultrastructural features of the process of wound healing after tail and limb amputation in lizardACTA ZOOLOGICA, Issue 3 2010L. Alibardi Abstract Alibardi, L. 2010. Ultrastructural features of the process of wound healing after tail and limb amputation in lizard.,Acta Zoologica (Stockholm) 91: 306,318 Wound healing and re-epitelization after amputation of tail and limb in lizard have been studied by electron microscopy to understand the cytological base of immunity to infection in this species. After 2 days post-amputation in both limb and tail stumps, numerous granulocytes are accumulated over the stump, and participate to the formation of the scab. Bacteria remain confined to the scab or are engulfed by leukocytes and migrating keratinocytes located underneath the scab. Bacteria are degraded within lysosomes present in these cells and are not observed among mesenchymal cells or in blood vessels of the regenerative blastema. Granulocytes, migrating keratinocytes, and later macrophages form an effective barrier responsible for limiting microbe penetration. The innate immunity in lizard is very effective in natural (dirty) condition and impedes the spreading of infection to inner tissues. While the complete re-epitelization of the tail stump underneath the scab requires 4,7 days, the same process in the limb requires 8,18 or more days post-amputation, depending from the level of amputation and the persistence of a protruding humerus or femurs on the stump surface. This delay produces the permanence of inflammatory cells such as granulocytes and macrophages in the limb stump for a much longer period than in the tail stump, a process that stimulates scarring. [source] Overexpression of GAP-43 modifies the distribution of the receptors for myelin-associated growth-inhibitory proteins in injured Purkinje axonsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2009Simona Foscarin Abstract Neurons with enhanced intrinsic growth capabilities can elongate their axons into non-permissive territories, but the mechanisms that enable the outgrowing processes to overcome environmental inhibition are largely unknown. To address this issue, we examined adult mouse Purkinje cells that overexpress the axonal growth-associated protein GAP-43. After injury, these neurons exhibit sprouting along the intracortical neuritic course and at the severed stump in the white matter. To determine whether GAP-43-overexpressing Purkinje cells are responsive to extrinsic inhibitory cues, we investigated the content and subcellular localization of major receptors for myelin-associated inhibitory proteins, PlexinB1 and the Nogo receptor (NgR) with the related co-receptors LINGO-1 and p75. Expression of these molecules, estimated by measuring perikaryal immunostaining intensity and Western blot, was not different in wild-type or transgenic mice, and it was not overtly modified after axotomy. Following injury, however, the content of PlexinB1 was significantly reduced in GAP-43-overexpressing neurites. Furthermore, in the same axons the distribution of both PlexinB1 and NgR was altered, being inverse to that of GAP-43. Labelling for the two receptors was conspicuously reduced on the axonal surface and it was almost undetectable in the outgrowing sprouts, which showed strong GAP-43 immunoreactivity. These observations indicate that although GAP-43 overexpression does not modify the expression of receptors for myelin-associated inhibitory factors, it interferes with their subcellular localization and exposure on the neuritic membrane. Therefore, GAP-43 promotes axon growth by multiple synergistic mechanisms that potentiate the intrinsic motility of the elongating processes, while reducing their sensitivity to environmental inhibition. [source] Adhesion and development of the root rot fungus (Heterobasidion annosum) on conifer tissues: effects of spore and host surface constituentsFEMS MICROBIOLOGY ECOLOGY, Issue 2 2000Frederick O Asiegbu Abstract The objective of this study was to correlate the occurrence of particular root and woody stump surface components with the ability of spores of the root rot fungus (Heterobasidion annosum) to adhere, germinate and establish on conifer tissues. With the aid of high performance liquid chromatography, several sugars (pinitol, xylitol, dulcitol, mannitol, D -glucose, mannose, fructose) were detected on both stump and fine root surfaces of Scots pine and Norway spruce. Of all the sugars observed, xylose and arabinose were poorly utilized for initiation of germ tube growth whereas spore germination was enhanced in the presence of D -glucose, mannose or fructose. Oxidation of these sugars by pretreatment of wood discs or roots with periodic acid abolished the ability of the spores to germinate. Non-sugar components such as long chain fatty acids on spores and root surfaces as detected with nuclear magnetic resonance were found to have a significant influence on adhesion and initiation of germ tube development. Removal of these aliphatic compounds from the root surface increased spore germination by 2-fold, whereas similar treatment on spores led to a 5-fold decrease in adhesiveness to root material. In vitro studies revealed that the di-ethyl ether extract from the roots had no long term adverse effect on spore germination which suggests that the fungus may possess the capability to detoxify this substance. Similarly, adhesion of spores was affected by low and freezing temperatures. The role of significant levels of mannitol and trehalose accumulated in spores and hyphae of the fungi on viability, survival and tolerance to adverse conditions such as oxidative stress, freezing and desiccation are discussed. [source] Associations among symptoms of dieback in even-aged stands of ash (Fraxinus excelsior L.)FOREST PATHOLOGY, Issue 1 2010J. P. Skovsgaard Summary The objective of this study was to establish statistically based associations among macroscopic symptoms of crown dieback, cankers due to Chalara fraxinea, and symptoms caused by other pathogens and pests on Fraxinus excelsior. A total of 454 trees were observed in two plots of a 15-year-old experimental stand. The symptoms included: (i) overall extent of crown dieback; (ii) dieback of upper parts of the crown; (iii) canker in upper parts of the crown; (iv) wilting foliage; (v) cankers and bark proliferations at the lower part of the stem; and (vi) discolouration at stump or stem base. The analysis suggested that the observed symptoms of crown dieback are caused by a primary disease. The macroscopic symptoms attributed to dieback and canker in the crown were strongly associated. Moreover, the disease was associated with symptoms of Armillaria gallica, but no associations were found for symptoms of Neonectria galligena, Pseudomonas syringae subsp. savastanoi pv. fraxini, Hylesinus fraxini or H. varius when considered collectively. Dieback was more frequent on trees of average or below-average size, suggesting that individual tree resistance decreased with decreasing growth potential or tree vigour. The extent of canker in the crown depended on site conditions and possibly on silvicultural practices. The development of phytosanitary prescriptions for silviculture should primarily be targeted towards young stands as these represent the most critical phases of stand development. [source] Occurrence of Heterobasidion basidiocarps on cull pieces of Norway spruce left on cutting areas and in mature spruce standsFOREST PATHOLOGY, Issue 6 2007M. M. Müller Summary Fruiting of Heterobasidion on cull pieces and stumps of Norway spruce was investigated in cutting areas and mature spruce stands located in southern Finland. Cull pieces of variable size and showing butt rot were left on three clear-cut areas and in one thinned stand. Additionally, a part of the cull pieces was transported to mature forest sites with closed canopy. During the succeeding 3,4 years the cull pieces were investigated annually for sporocarps of Heterobasidion, and the area of actively sporulating pore layer of each sporocarp was measured. Root bases of spruce stumps in the logging areas were excavated and sporocarps found on the stumps also measured. At the onset of the experiment, Heterobasidion spp. were isolated from 76% of the cull pieces showing butt rot; 85% of the isolates were identified as H. parviporum and 15% as H. annosum s.s. During the following 3,4 years sporocarps were found on 20% of the 1938 cull pieces where Heterobasidion butt rot was initially detected visually. Sporocarp formation was promoted by advancement of butt rot, increasing cull piece diameter and end-to-end ground contact, but restricted by the colonization of the cull piece by Stereum sanguinolentum. Between-site differences were significant but could not be explained by differences in tree cover. At the end of the investigation period the average sporulating area of Heterobasidion sporocarp per metre of cull piece was higher than the average sporulating area per stump at three of four logging sites. Hence, leaving cull pieces containing Heterobasidion butt rot at logging areas in southern Finland can considerably increase local production of Heterobasidion spores. [source] Complete robotic-assistance during laparoscopic living donor nephrectomies: An evaluation of 38 procedures at a single siteINTERNATIONAL JOURNAL OF UROLOGY, Issue 11 2007Jacques Hubert Objective: To evaluate our initial experience with entirely robot-assisted laparoscopic live donor (RALD) nephrectomies. Methods: From January 2002 to April 2006, we carried out 38 RALD nephrectomies at our institution, using four ports (three for the robotic arms and one for the assistant). The collateral veins were ligated, and the renal arteries and veins clipped, after completion of ureteral and renal dissection. The kidney was removed via a suprapubic Pfannenstiel incision. A complementary running suture was carried out on the arterial stump to secure the hemostasis. Results: Mean donor age was 43 years. All nephrectomies were carried out entirely laparoscopically, without complications and with minimal blood loss. Mean surgery time was 181 min. Average warm ischemia and cold ischemia times were 5.84 min and 180 min, respectively. Average donor hospital stay was 5.5 days. None of the transplant recipients had delayed graft function. Conclusions: Robot-assisted laparoscopic live donor nephrectomy can be safely carried out. Robotics enhances the laparoscopist's skills, enables the surgeon to dissect meticulously and to prevent problematic bleeding more easily. Donor morbidity and hospitalization are reduced by the laparoscopic approach and the use of robotics allows the surgeon to work under better ergonomic conditions. [source] Laparoscopic management of urachal remnants in adulthoodINTERNATIONAL JOURNAL OF UROLOGY, Issue 12 2006TAKATSUGU OKEGAWA Background: The aim of this study was to investigate the outcome of laparoscopic excision of urachal remnants (LUR), and to compare the outcome with that of the traditional open excision of urachal remnants (OUR). Methods: Between February 2001 and December 2005, six patients with a mean age of 23.8 years who had a symptomatic urachal sinus underwent radical LUR. Using 12 mm and 5 mm ports, the caudal stump of the urachus was ligated with an absorbable clip and divided. The peritoneal and preperitoneal tissue between the medial umbilical ligaments was dissected free of the transversalis fascia. Dissection was carried out along the preperitoneal plane toward the umbilicus. The cephalic side of the lesion was ligated at the umbilicus with an endo-loop and divided. In addition, four patients who underwent a traditional OUR were included. Peri- and postoperative records were reviewed to assess morbidity, recovery, and outcome. Results: The operative duration was not significantly shorter for the LUR group than the OUR group, but there was generally a reduction in blood loss (mean 16.5 vs 68.3 mL), an earlier resumption of eating (mean 1.3 vs 2.5 days), and a shorter hospital stay (mean 5.3 vs 10.5 days). There were no intraoperative complications in either the LUR or the OUR group. Mean follow up was 5 (range 4,12) months. There were no postoperative complications. Conclusions: The results suggest that LUR can be safely and satisfactorily performed in adulthood. [source] CT Coronary Angiography Predicts the Outcome of Percutaneous Coronary Intervention of Chronic Total OcclusionJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2007F.R.A.C.P., KEAN H. SOON M.B.B.S. Background: The success rate of percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) is relatively low. Further evaluation of CTO lesion with CT coronary angiography (CT-CA) may help to better select patients that would benefit from percutaneous revascularization. We aimed to test the possible association between failed PCI and transluminal calcification of CTO as assessed by CT-CA. Methods: Patients with CTO awaiting PCI were scanned with a 16-slice CT. A cardiologist and a radiologist assessed transluminal calcification of CTO lesions on CT images while an interventional cardiologist at a core laboratory assessed conventional variables of invasive fluoroscopic coronary angiography (FCA) associated with failed PCI of CTO. The significance of CT and FCA variables in association with failed PCI were analyzed. Results: In a cohort of 39 patients with 43 CTO lesions, 24 lesions were successfully revascularized. Transluminal calcification ,50% as assessed on CT-CA was strongly associated with failed PCI (odds ratio [OR] of PCI success = 0.10, 95% confidence interval [CI]: 0.02,0.47, P = 0.003). Blunt stump as seen on FCA was also associated with failed PCI (OR of PCI success = 0.24, 95% CI: 0.07,0.86, P = 0.029). There was no significant evidence to support that the duration of CTO, presence of side branch and bridging collaterals, and the absence of microchannels as assessed with FCA were associated with failed PCI. On multivariate analysis, transluminal calcification ,50% on CT-CA was the only significant predictor of failed PCI. Conclusions: Heavy transluminal calcification as assessed with CT-CA is an independent predictor of failed PCI of CTO. CT-CA may have a role in the work-up of CTO patients prior to PCI. [source] Local isoform-specific NOS inhibition: A promising approach to promote motor function recovery after nerve injuryJOURNAL OF NEUROSCIENCE RESEARCH, Issue 9 2010Bernardo Moreno-López Abstract Physical injury to a nerve is the most frequent cause of acquired peripheral neuropathy, which is responsible for loss of motor, sensory and/or autonomic functions. Injured axons in the peripheral nervous system maintain the capacity to regenerate in adult mammals. However, after nerve transection, stumps of damaged nerves must be surgically joined to guide regenerating axons into the distal nerve stump. Even so, severe functional limitations persist after restorative surgery. Therefore, the identification of molecules that regulate degenerative and regenerative processes is indispensable in developing therapeutic tools to accelerate and improve functional recovery. Here, I consider the role of nitric oxide (NO) synthesized by the three major isoforms of NO synthases (NOS) in motor neuropathy. Neuronal NOS (nNOS) seems to be the primary source of NO that is detrimental to the survival of injured motoneurons. Endothelial NOS (eNOS) appears to be the major source of NO that interferes with axonal regrowth, at least soon after injury. Finally, NO derived from inducible NOS (iNOS) or nNOS is critical to the process of lipid breakdown for Wallerian degeneration and thereby benefits axonal regrowth. Specific inhibitors of these isoforms can be used to protect injured neurons from degeneration and promote axonal regeneration. A cautious proposal for the treatment of acquired motor neuropathy using therapeutic tools that locally interfere with eNOS/nNOS activities seems to merit consideration. © 2010 Wiley-Liss, Inc. [source] Expression of interleukin-1,, cyclooxygenase-2, and prostaglandin E2 in a rotator cuff tear in rabbitsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2007Hiroshi Koshima Abstract We investigated the specific factors related to shoulder pain due to a rotator cuff tear using a model in rabbits. A rotator cuff tear was surgically created, and the expression of interleukin-1, (IL-1,), prostaglandin E2 (PGE2), and cyclooxygenase-2 (COX-2) was analyzed. In the supernatant of the tissue culture of the torn tendon, IL-1, production was detected. The amount of IL-1, was highest 1 day after injury, and then decreased gradually to 21 days. PGE2, the mediator of pain and the product of COX-2, was also detected in the supernatant of the tissue culture. The production of PGE2 significantly increased to 7 days after injury, and then decreased to 21 days. RT-PCR analysis confirmed the mRNA expression of IL-1, and COX-2 in the torn tendon. Immunohistochemical study demonstrated that cells in the tendon stump were immunopositive for IL-1, and COX-2. Furthermore, in the affected joint, articular chondrocytes in the remote area from the tear expressed COX-2 strongly. When the rotator cuff is torn, IL-1, is produced in the torn tendon, and stimulates the expression of COX-2 in not only the torn tendon but also in articular chondrocytes. The COX-2 then produces PGE2, which would mediate shoulder pain. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:92,97, 2007 [source] Skin problems in lower limb amputees: an overview by case reportsJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 2 2007HEJ Meulenbelt Abstract The stump in lower limb amputees is prone to skin problems because it is exposed to several unnatural conditions (shear and stress forces and increased humidity) when a prosthesis is used. This study reviews the literature on case reports of lower limb amputees with skin problems on the stump. In total, 56 reports comprising 76 cases were identified in the literature. The main disorders are acroangiodermatitis, allergic contact dermatitis, bullous diseases, epidermal hyperplasia, hyperhidrosis, infections, malignancies and ulcerations. [source] Nerve conduits and growth factor delivery in peripheral nerve repairJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2007Lukas A. Pfister Abstract Peripheral nerves possess the capacity of self-regeneration after traumatic injury. Transected peripheral nerves can be bridged by direct surgical coaptation of the two nerve stumps or by interposing autografts or biological (veins) or synthetic nerve conduits (NC). NC are tubular structures that guide the regenerating axons to the distal nerve stump. Early synthetic NC have primarily been made of silicone because of the relative flexibility and biocompatibility of this material and because medical-grade silicone tubes were readily available in various dimensions. Nowadays, NC are preferably made of biodegradable materials such as collagen, aliphatic polyesters, or polyurethanes. Although NC assist in guiding regenerating nerves, satisfactory functional restoration of severed nerves may further require exogenous growth factors. Therefore, authors have proposed NC with integrated delivery systems for growth factors or growth factor,producing cells. This article reviews the most important designs of NC with integrated delivery systems for localized release of growth factors. The various systems discussed comprise NC with growth factors being released from various types of matrices, from transplanted cells (Schwann cells or mesenchymal stem cells), or through genetic modification of cells naturally present at the site of injured tissue. Acellular delivery systems for growth factors include the NC wall itself, biodegradable microspheres seeded onto the internal surface of the NC wall, or matrices that are filled into the lumen of the NC and immobilize the growth factors through physical-chemical interactions or specific ligand-receptor interactions. A very promising and elegant system appears to be longitudinally aligned fibers inserted in the lumen of a NC that deliver the growth factors and provide additional guidance for Schwann cells and axons. This review also attempts to appreciate the most promising approaches and emphasize the importance of growth factor delivery kinetics. [source] The effect of hyperbaric oxygen treatment on early regeneration of sensory axons after nerve crush in the ratJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2002Fajko F. Bajrovi Abstract The effect of hyperbaric oxygen treatment (HBO) on sensory axon regeneration was examined in the rat. The sciatic nerve was crushed in both legs. In addition, the distal stump of the sural nerve on one side was made acellular and its blood perfusion was compromised by freezing and thawing. Two experimental groups received hyperbaric exposures (2.5 ATA) to either compressed air (pO2 = 0.5 ATA) or 100% oxygen (pO2 = 2.5 ATA) 90 minutes per day for 6 days. Sensory axon regeneration in the sural nerve was thereafter assessed by the nerve pinch test and immunohistochemical reaction to neurofilament. HBO treatment increased the distances reached by the fastest regenerating sensory axons by about 15% in the distal nerve segments with preserved and with compromised blood perfusion. There was no significant difference between the rats treated with different oxygen tensions. The total number of regenerated axons in the distal sural nerve segments after a simple crush injury was not affected, whereas in the nerve segments with compromised blood perfusion treated by the higher pO2, the axon number was about 30% lower than that in the control group. It is concluded that the beneficial effect of HBO on sensory axon regeneration is not dose-dependent between 0.5 and 2.5 ATA pO2. Although the exposure to 2.5 ATA of pO2 moderately enhanced early regeneration of the fastest sensory axons, it decreased the number of regenerating axons in the injured nerves with compromised blood perfusion of the distal nerve stump. [source] A long-term record of Quercus decline, logging and fires in a southern Swedish Fagus - Picea forestJOURNAL OF VEGETATION SCIENCE, Issue 6 2002Mats Niklasson Tutin et al. (1964,1976) Abstract. We reconstructed forest development and disturbance events (fire and logging) during the last 1000 yr with tree-ring data, pollen and charcoal analysis from a semi-natural Fagus sylvatica-Picea abies forest (ca. 1 km2) in the hemiboreal zone. According to pollen analysis, Quercus robur together with Pinus sylvestris was abundant in the forest until the turn of the 18th/19th centuries when these species disappeared completely (Quercus) or nearly completely (Pinus) and were replaced by Fagus and Picea. The disappearance of Quercus was corroborated by the remarkable discovery of a single Quercus stump that had been cut in the 18th century and had become overgrown and preserved by a very old Picea. In total 11 fires were dated from 1555 to 1748 from fire scars in several Pinus stumps cut 100 - 200 yr ago. Since the last fire in 1748, no Quercus or Pinus have regenerated in the core of the reserve apart from single pines in neighbouring managed forest (80 yr ago). During the period of documented fires Fagus was protected from fires in a refuge made up of large boulders. Picea colonized the region at the time when the fires ceased 250 yr ago. We hypothesize that most of the fires were probably of human origin because of their patchiness and high frequency compared to the natural background levels of lightning ignitions in the region. On a 300-yr time scale, logging and fire suppression seem to strongly overshadow the effect of climate change on forest composition and dynamics. [source] Tailoring donor hepatectomy per segment 4 venous drainage in right lobe live donor liver transplantationLIVER TRANSPLANTATION, Issue 6 2004See Ching Chan Including the middle hepatic vein (MHV) in the right lobe liver graft for adult-to-adult live donor liver transplantation provides more functional liver by securing adequate venous drainage. Donor outcome of this procedure in relation to different venous drainage patterns of segment 4 is unknown. Modification of graft harvesting technique by preserving segment 4b hepatic vein (V4b) in theory compensates for unfavorable venous drainage patterns. Consecutive 120 right lobe live donors were included. Computed tomography was studied in detail to assign each donor to one of the three types of the Nakamura classification of venous drainage pattern of segment 4. Type I drainage was mainly via the left hepatic vein (LHV), type II drainage was equally into the MHV and LHV, and type III drainage was predominantly into the MHV. Any distinct umbilical vein was also noted. In the early part of the series, the V4b draining into the MHV was divided to provide a long MHV stump in the graft. In the later part of the series, prominent V4b draining into the MHV was preserved in the donor as far as possible. Donor outcomes were measured by peak values of prothrombin time (PT), serum bilirubin and transaminases levels. There was no donor mortality. Type I donors (n=69) had the best outcome with peak PT of 17.9 sec (range 12.3,23.3 sec). Type II donors (n=44) had peak PT of 18.5 sec (range 15.4,24.4 sec). When V4b was preserved in type II donors (n=19), the peak PT (18.0 sec, range 15.4,20.7 sec) became significantly lower than that of type II donors who had V4b sacrificed (20.3 sec, range 16.2,24.4 sec) (P=0.001). A distinct umbilical vein (n=91, 75.8%) was insignificant for donor outcome measured by peak PT. Multivariate analysis identified that type II donors with V4b sacrificed (n=25), type III donors (n=7), and the first 50 cases had less favorable outcomes. In conclusion, unfavorable venous drainage patterns were one of the independent factors compromising postoperative donor liver function, but was circumvented by preservation of V4b. (Liver Transpl 2004;10:755,762.) [source] Microvessels Promote Motor Nerve Survival and Regeneration Through Local VEGF Release Following Ectopic ReattachmentMICROCIRCULATION, Issue 8 2004SHAWN E. BEARDEN ABSTRACT Objectives: Nerves and blood vessels form a close association during embryogenesis. Growth and guidance factors initially attributed to either nerves or vessels are now known to affect both tissues; prominent among these is vascular endothelial growth factor (VEGF). The authors investigated whether axons would associate with blood vessels in a regenerating system and questioned whether VEGF is integral to neurotization following axotomy. Methods: In hamsters 8,12 weeks of age, the accessory nerve (CN XI) to the retractor muscle of the cheek pouch was cut and the proximal stump was reattached ectopically onto the muscle. Vascular casting and immunolabeling were used to quantify the extent of neurovascular association during regeneration. A role for VEGF was investigated using immunolocalization of VEGF and its receptor (sVEGFR2) as well as local sequestration of VEGF with soluble receptor (sVEGFR1). Results: Regenerating axons aligned with microvessels of the vasa nervorum along a "chaperone" region during outgrowth from the reattachment site and while entering the muscle. In this ,1-mm region, VEGF protein was expressed by growing microvessels despite a ,50% reduction (p < .05) in total muscle VEGF concentration. VEGFR2 was expressed by regenerating axons and growth cones. Sequestration of VEGF by sVEGFR1 impaired neurotization by ,40% (p < .05). The chaperone region ended where regenerating microvessels anastomosed with the native microcirculation and their expression of VEGF protein diminished. Conclusions: Regenerating axons and blood vessels align during outgrowth from ectopic reattachment. This interaction dissipates as vascular anastomoses form with established microvessels and axons target muscle fibers. Local production of VEGF by growing microvessels supports motor nerve survival and regeneration. [source] Transfer of the second to the first metatarsal ray in a case of lawn mower injury: A case reportMICROSURGERY, Issue 3 2009Paolo Sassu M.D. The medial longitudinal arch of the foot plays a major role for a physiologic transfer of the load from the heel to the forefoot during walking and running. Traumatic amputation that involve either the great toe or the whole first metatarsal bone can lead to collapse of the medial longitudinal arch, overload of the metatarsal heads, and painful callus formation. If replant of the amputated part is not possible or has failed, it is advisable to reconstruct the medial longitudinal arch in order to re-establish a functional transfer of the load in the foot. We present a case of a young lady who suffered from traumatic amputation at the distal third of the first metatarsal. Replantation failed due to the severity of the initial injury. Despite a good coverage of the defect with a lateral arm flap, the patient developed a painful plantar callus underneath the amputated stump. The adjacent second metatarsal ray was then raised as a pedicled flap including bone and soft tissues and transferred to the first ray in order to reconstruct a physiologic medial longitudinal arch. The patient had excellent functional results with no recurrence of the callus. © 2008 Wiley-Liss, Inc. Microsurgery, 2009. [source] Fabricating autologous tissue to engineer artificial nerveMICROSURGERY, Issue 4 2002Biao Cheng M.D. This study reports on the successful fabrication of artificial nerves with tissue engineering methods. Schwann cells were cultured for 2 weeks, seeded on polyglactin 910 scaffolds, and biomembrane-coated with rat-tail glue and laminin. Observation of the scaffolds' adsorptivity to Schwann cells, and of the growth and migration of Schwann cells, was made using a light microscope, and by scanning and transmission electron microscopy. The Schwann cells were able to migrate and proliferate on the polyglactin 910 fiber. Schwann cells were well-distributed, and formed a Büngner band on which the Schwann cells produced more matrices. Schwann cells on the biomembrane also grew well. We investigated the role of the tissue engineering conduit guide in vivo, using an established rabbit peripheral nerve regeneration model. At 8 weeks, axonal regeneration was observed in the distal nerve stump. Adult Schwann cells can be produced on the coated fiber and the biomembrane. Three-dimensional scaffolds with Schwann cells had the basic characteristics of the artificial nerve. These findings will provide a practical method for fabricating tissue-engineered artificial nerve to repair long nerve defects. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:133,137 2002 [source] Nerve regeneration through a healthy peripheral nerve trunk as a nerve conduit: A preliminary study of a new concept in peripheral nerve surgeryMICROSURGERY, Issue 4 2002Fuat Yüksel M.D. The popularity of nerve conduits has increased recently due to the need for alternative nerve reconstruction techniques, obviating the harvest of nerve grafts. Based on ideas suggesting nerve tissue itself, which was the most physiologic environment for nerve regeneration, a study using 40 sciatic nerves of 20 rats was performed. The proximal stumps of transected peroneal nerves were sutured to the lateral wall of healthy tibial nerve trunks after removal of the epineurium. Twelve weeks later, tissue samples were taken from the anastomosis sites and from the levels above and below these sites. Configurations of fascicles were evaluated, and numbers of fibers were estimated. It was observed that the fibers of peroneal nerves regenerated into and through the tibial nerve trunk distally. This suggested that active regenerating fibers of a proximal stump of a nerve could regenerate and progress as a fascicular unit in optimum condition at the trunk of another healthy nerve. This preliminary study should stimulate further studies based on this new concept: that a nerve trunk can serve as the host for the regenerating fibers of another nerve. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:138,143 2002 [source] A reconstructed digit by transplantation of a second toe for control of an electromechanical prosthetic handMICROSURGERY, Issue 1 2002Zhong Wei Chen M.D. The treatment options for the loss of an entire human hand and part of the forearm are currently limited to the transplantation of toe(s) to the amputation stump or a Krukenberg's bifurcation hand, and using a cosmetic or functional prosthesis. The functional prosthetic hand, such as the prevailing myoelectrically controlled prosthetic hand, has an action accuracy that is affected by many factors. The acceptance rate of the three planes freedom myoelectronic hand by the patients was 46,90% because of poor function caused by the weakness of signal and strong external interference. In this report, the left second toe was transplanted to the patient's forearm amputation stump. Mandates from the brain are relayed by the action of this reconstructed digit, to control a special designed multidimension freedom electronic prosthetic hand. After rehabilitation and adaptation training, the correct recognition rate of the electronic prosthetic hand controlled by this reconstructed digit is a remarkable 100%. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:5,10, 2002 DOI 10.1002/micr.22002 [source] Processed porcine collagen tubulization versus conventional suturing in peripheral nerve reconstruction: An experimental study in rabbitsMICROSURGERY, Issue 3 2001Guda C.M. Heijke M.D. In peripheral nerve reconstruction, various procedures are used. One of the procedures that received the most interest in the past decade is the tubulization technique for small nerve gaps. A disadvantage in the use of non-biodegradable tubes is that the material often has to be removed owing to its mechanical properties. Some investigators, in exploring the use of collagen tubes, being a natural biodegradable material, found either allogenicity or xenogenicity and immune responses that may inhibit nerve regeneration. Processed porcine collagen (PPC) is a new inert and biodegradable material that has a favorable effect on wound healing, as demonstrated by experiments on other tissues. The aim of our study was to compare the healing of nerve sutures with PPC tubes with conventional end-to-end sutures. In our experiments, we reconstructed the saphenous nerves of 27 rabbits. In series 1 (n = 12) and 2 (n = 12), PPC tubes were slid over an end-to-end nerve suture without or with a 10-mm nerve gap, respectively. In series 3 (n = 12), conventional suturing was performed in the collateral saphenous nerves of the animals of series 1. Epineurial suturing was performed. Three other non-operated saphenous nerves served as controls. The healing was studied after 3, 6, and 12 months in sections stained by monoclonal antibodies and by conventional histologic staining. Morphometric analysis of the regenerating axons was done by using confocal scanning laser microscopy (CLSM). Data analysis was carried out using a software program especially developed for this purpose. All results were evaluated statistically. Our results showed that during the healing period in the distal nerve stump, the number of axons of the PPC procedure with a 10-mm gap was significantly higher than that in the procedure without a gap. At 12 months, the mean number of axons of all procedures was significantly lower than in the non-operated nerve, and the mean axon diameter in all distal stumps did not differ significantly from that of the non-operated nerve. In the distal nerve stump, the ratio of total axon area to total fascicle area in the PPC procedure with a gap was significantly higher than that in the conventional suturing procedure. After 12 months, there was no significant difference between the percentages of axon outgrowth of the PPC procedure without a gap, the conventional suturing procedure, and the non-operated nerve (100%). The percentage of axon outgrowth in PPC with a gap was significantly higher than in the other procedures. © 2001 Wiley-Liss, Inc. Microsurgery 21:84,95 2001 [source] Spinal myoclonus responsive to topiramateMOVEMENT DISORDERS, Issue 11 2004Antonio Siniscalchi MD Spinal segmental myoclonus rarely occurs in peripheral neurological disorders. There are no data about the efficacy of topiramate (TPM) on spinal myoclonus. We describe a patient whose segmental myoclonus in amputation stump was ameliorated markedly by TPM. © 2004 Movement Disorder Society [source] Arterial anastomosis in a pediatric patient receiving a right extended split liver transplant: A case reportPEDIATRIC TRANSPLANTATION, Issue 4 2009Roberto Verzaro Abstract:, We report a case of a pediatric patient who received a right-extended liver transplant. The size of the recipient hepatic artery did not match with the donor right hepatic arterial stump. Moreover, recipient arterial anatomy made the direct anastomosis difficult or at increased risk for complications. The recipient's splenic artery was then mobilized, divided and anastomosed to the donor's right hepatic artery. The spleen was preserved and revascularization through collaterals is demonstrated by Angio CT Scan. Doppler US of the transplanted liver demonstrated good flow through the liver and the patient was discharged with perfect liver function. Splenic artery is perfectly suited for hepatic artery anastomosis. The use of splenic artery is favored in particular situations as in the case of a pediatric recipient receiving a right-extended liver graft with small caliber artery. [source] Rabbit Facial Nerve Regeneration in Autologous Nerve Grafts After Antecedent Injury ,THE LARYNGOSCOPE, Issue 4 2000FACS, J. Gershon Spector MD Objective The effect of incomplete antecedent injuries on subsequent facial nerve regeneration within cable graft repairs is not known. The purpose of this study is to compare facial nerve regeneration after an immediate and delayed neural cable graft repair. Method Rabbit facial nerve regeneration after complete transectional injuries of the buccal division was compared in two experimental models. In one, a 10-mm segment of the nerve was transected, rotated 180°, and immediately repaired as a cable graft (N=8). In the second, a preliminary nerve crush was allowed to recover over a 4-week period and a 10-mm segment of nerve centered on the crush site was then transected, rotated 180°, and delay repaired as a cable graft (N = 7). Data are presented as total numbers of regenerating myelinated axons that traverse the surgical repair to innervate the cable graft and distal nerve stumps, as well as the percentage of regenerating neurites compared with preoperative pooled and individual controls. Subpopulations of regenerating neurons are delineated to quantify the pattern of neural innervation. Results Five weeks after cable graft repair both groups had similar myelinated outgrowth from the proximal nerve stump across the proximal anastomosis to innervate the cable graft (3995 ± 1209 vs. 3284 ± 651;P = .89). However, the delayed repair group had more intrafascicular regeneration within cable grafts (2261 ± 931 vs. 1660 ± 1169;P = .02) and distal nerve stump (1532 ± 281 vs. 445 ± 120;P = .004) than the immediate repair group. The immediate repair group had greater extrafascicular nerve regeneration in the cable graft (2335 ± 1954 vs. 437 ± 236;P = .001) and more myelin and axonal debris in pre-existing neural fascicles of the cable graft (P = .02) and distal nerve stump (463 ± 187 vs. 103 ± 87;P = .02). Conclusions Antecedent priming lesions do not enhance axonal survival as determined by regenerating myelinated axonal counts. However, antecedent injuries enhance the efficiency of neural innervation of the affected mimetic musculature by increasing the number of myelinated intrafascicular neural regenerants in the cable graft and distal nerve stump. This is accomplished by two factors: increased perineural fibrosis and decreased intrafascicular myelin and axonal debris. [source] Ultrastructure of sperm ,tail stump' defect in wild boarANDROLOGIA, Issue 1 2009M. L. Fischman Summary Sperm ,tail stump' defect was found in ejaculates of a wild boar maintained in captivity. It was in good physical condition, the testes and genital tract were found to be of normal size and consistency. There was no evidence of macroscopic abnormalities at the clinical analysis and at necropsy. The volume and concentration of the semen samples obtained by electroejaculation were lower than normal. The slides examined contained a high level of abnormal spermatozoa (52.7%). The most frequent morphological finding was a droplet-like form attached to the base of the head or a very short stump. The non-stumped spermatozoa had no normal tail but a shortened one. Analysing the histological structure with light microscopy, no ring of spermatozoa was observed lining the lumen of the seminiferous tubules and the characteristically cellular structure was not conserved. The ultrastructural examination evidenced a disorganisation of the normal tubular structure of the flagellum, with lost of regular pattern of the axial bundle of fibrils and the mitochondrial helix. The origin of this abnormality is unknown. [source] Defining the role of surgery for complications after pancreatoduodenectomyANZ JOURNAL OF SURGERY, Issue 1-2 2009Parul J Shukla Abstract Background:, Although mortality rates following pancreatoduodenectomy have drastically reduced over the last few decades, high morbidity rates have continued to trouble pancreatic surgeons across the world. Interventional radiology has reduced the need for re-exploration for complications following pancreatoduodenectomy. There remain specific indications for re-exploration in such scenarios. It is thus pertinent to identify those clinical scenarios where surgery still has a role in managing complications of pancreatoduodenectomy. The aim of the study was to define the role of surgery for dealing with complications following pancreatoduodenectomy. Methods:, One hundred and fifty-seven consecutive pancreatoduodenectomies carried out at a single institution between 1 January 2001 and 28 February 2007, were analysed. The database was looked into to identify patients who underwent re-exploration for complications and to define the indications for the exploration in these patients. Results:, Out of the 157 pancreatoduodenectomies, there were, in all, 39 complications (24.2%) in 38 patients. Most of these complications were successfully managed conservatively and with the help of interventional radiology. Seventeen patients had to be re-explored (10.8%). The indications were primarily for haemorrhage, clinically significant pancreatic leaks, biliary leaks, adhesive intestinal obstruction and burst abdomen. The overall mortality rate was 3.1%. The mortality rate in the patients undergoing re-exploration was 11.7%. Conclusion:, Early haemorrhage (from the pancreatic stump or anastomotic line), clinically significant pancreatic anastomotic leak with discharge from the main wound and an early biliary anastomotic leak are prime indications for re-exploration in patients with complications following pancreatoduodenectomy. [source] | ||||||||||||||||||||||