Abnormal reaction to central nervous system injury in mice lacking glial fibrillary acidic protein and vimentin.
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In response to injury of the central nervous system, astrocytes become reactive and express high levels of the intermediate filament (IF) proteins glial fibrillary acidic protein (GFAP), vimentin, and nestin. We have shown that astrocytes in mice deficient for both GFAP and vimentin (GFAP-/-vim-/-) cannot form IFs even when nestin is expressed and are thus devoid of IFs in their reactive state. Here, we have studied the reaction to injury in the central nervous system in GFAP-/-, vimentin-/-, or GFAP-/-vim-/- mice. Glial scar formation appeared normal after spinal cord or brain lesions in GFAP-/- or vimentin-/- mice, but was impaired in GFAP-/-vim-/- mice that developed less dense scars frequently accompanied by bleeding. These results show that GFAP and vimentin are required for proper glial scar formation in the injured central nervous system and that some degree of functional overlap exists between these IF proteins. (+info)
Leukocyte infiltration, neuronal degeneration, and neurite outgrowth after ablation of scar-forming, reactive astrocytes in adult transgenic mice.
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Reactive astrocytes adjacent to a forebrain stab injury were selectively ablated in adult mice expressing HSV-TK from the Gfap promoter by treatment with ganciclovir. Injured tissue that was depleted of GFAP-positive astrocytes exhibited (1) a prolonged 25-fold increase in infiltration of CD45-positive leukocytes, including ultrastructurally identified monocytes, macrophages, neutrophils, and lymphocytes, (2) failure of blood-brain barrier (BBB) repair, (3) substantial neuronal degeneration that could be attenuated by chronic glutamate receptor blockade, and (4) a pronounced increase in local neurite outgrowth. These findings show that genetic targeting can be used to ablate scar-forming astrocytes and demonstrate roles for astrocytes in regulating leukocyte trafficking, repairing the BBB, protecting neurons, and restricting nerve fiber growth after injury in the adult central nervous system. (+info)
Neuroimaging of a wooden foreign body retained for 5 months in the temporalis muscle following penetrating trauma with a chopstick--case report.
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A 48-year-old female was stabbed by her husband with a chopstick made of wood in the left temporal region during a quarrel. She suffered laceration of the left temporal scalp. At initial examination, she concealed the assault with a chopstick. Radiography showed no abnormality, so the wound was sutured. One month after the injury, a painless subcutaneous mass appeared in the left temporal region which grew rapidly for 3 months. She was then admitted to our department. Computed tomography (CT) on admission showed a hyperdense area at the center of the mass. This area was hypointense on both T1- and T2-weighted magnetic resonance (MR) images. Temporalis muscle tumor with accompanying central necrosis, old hematoma, and inflammatory granuloma was considered. The mass was totally resected for cosmetic purposes and was found to be wooden foreign body granuloma. High density on CT and hypointensity on both T1- and T2-weighted MR images are characteristic of a chronically retained wooden foreign body in the living body and are useful for detecting wooden foreign bodies in the chronic granulomatous phase. (+info)
Organisation of hospital responses for the trauma epidemic.
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The caseload of the Department of Surgery (Baragwanath Hospital, Johannesburg, South Africa) is characterised by a singularly heavy trauma component. Penetrating injuries account for the majority of cases. The management of penetrating trauma is not as demanding as that of blunt trauma, yet the sheer number of cases, over the past four decades, has imposed a clinical burden that has never been met by commensurate resources. The organisation of the hospital and departmental responses has manifested itself on two different levels. The first one is the structural and functional deployment of insufficient staff, facilities and equipment to cope as flexibly as possible with the trauma epidemic. The second one is the gradual adaptation of the clinical management philosophy to ensure that the best possible quality of care is provided to the majority of trauma victims, with the full knowledge that better resources would sometimes have elicited a different clinical approach. (+info)
Characteristics of glial reaction in the perinatal rat cortex: effect of lesion size in the 'critical period'.
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In this study we investigate the capability of lesions, performed between embryonic day E18 and postnatal day P6, to provoke glial reaction. Two different lesion types were applied: 'severe' lesion (tissue defect) and 'light' lesion (stab wound). The glial reaction was detected with immunostaining against glial fibrillary acidic protein. When performed as early as P0, severe lesions could result in reactive gliosis, which persisted even after a month. The glial reaction was detected at P6/P7 and became strong by P8, regardless of the age when the animals were lesioned between P0 and P5. Namely, a strict limit could be estimated for the age when reactive glia were already found rather than for the age when glial reaction-provoking lesions could occur. After prenatal lesions, no glial reaction developed, but the usual glia limitans covered the deformed brain surface. Light lesions provoked glial reactions when performed at P6. In conclusion, three scenarios were found, depending on the age of the animal at injury: (i) healing without glial reaction, regardless of the remaining deformation; (ii) depending on the size of the lesion, either healing without residuum or with remaining tissue defect plus reactive gliosis; and (iii) healing always with reactive gliosis. The age limits between them were at P0 and P5. The glial reactivity seemingly appears after the end of the neuronal migration and just precedes the massive transformation of the radial glia into astrocytes. Estimating the position of the appearance of glial reactivity among the events of cortical maturation can help to adapt the experimental results to humans. (+info)
Esophageal perforation in a sword swallower.
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We present the case of a 59-year-old man who sustained an esophageal perforation as a result of sword swallowing. An esophagogram established the diagnosis, and surgical repair was attempted. However, 19 days later, a persistent leak and deterioration of the patient's condition necessitated a transhiatal esophagectomy with a left cervical esophagogastrostomy. The patient recovered and has resumed his daily activities at the circus, with the exception of sword swallowing. This case report presents an unusual mechanism for a potentially lethal injury. Our search of the English-language medical literature revealed no other report of esophageal perforation resulting from sword swallowing. Management of such an injury is often difficult, and a favorable outcome is dependent on prompt diagnosis and treatment. (+info)
Rhinotopy is disrupted during the re-innervation of the olfactory bulb that follows transection of the olfactory nerve.
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Re-innervation of the olfactory bulb was investigated after transection of the olfactory nerve using monoclonal antibody RB-8 to assess whether rhinotopy of the primary olfactory projection is restored. In normal animals RB-8 heavily stains the axons, and their terminals, that project from the ventrolateral olfactory epithelium onto glomeruli of the ventrolateral bulb (termed RB-8(+)). In contrast, axons from dorsomedial epithelium are unlabeled (RB-8(-)) and normally terminate in the dorsomedial bulb. Sprague-Dawley rats underwent unilateral olfactory nerve transection and survived for 6 weeks prior to perfusion, sectioning and immunostaining with RB-8. Nerve lesion does not shift the position of the boundary between RB-8(+) and RB-8(-) regions of the epithelium. However, following transection and bulb re-innervation, the distribution of RB-8(+) and RB-8(-) axons is markedly abnormal. First, in all 10 experimental animals RB-8(-) axons displace RB-8(+) axons from anterior glomeruli. Furthermore, the usual target of the RB-8(-) fibers, i.e. the dorsomedial bulb at more posterior levels of the bulb, remains denervated, judging by the lack of staining with antibodies that label axons derived from all epithelial zones. Finally, RB-8(+) fibers invade foreign territory in the dorsolateral bulb on the lesioned side in some cases. The shifts in terminal territory in the bulb after transection contrast with the restoration of the normal zonal patterning of the projection after recovery from methyl bromide lesion, but is consistent with reports of mistargeting by a receptor-defined subset of neurons after transection. (+info)
Unusual stab wound of the temporal region.
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We report the case of an unusual penetrating injury of the temporal region of the head caused by knife. A long kitchen knife was protruding from the upper auricular area of the left temporal region of victims head. It cut through the posterosuperior part of the left auricula and remained fixed to the postauricular region. Brain computorized tomography (CT) scan revealed that the knife had reached deep into the petrous part of the temporal bone, and was directed toward the sulcus of the sigmoid sinus. There were no signs of intracranial bleeding. An otorhinolaryngologist and a neurosurgeon removed the knife in operating room, with the patient in general anesthesia. The audiogram obtained after 7 days of hospitalization showed left conductive hearing loss of 40 dB at frequencies up to 2 kHz, and of 90 dB above 2 kHz, probably due to hemotympanum caused by the operation. Control examinations performed 14 days and one month after discharge confirmed the patients complete recovery and no significant defects in his hearing or balance. We suggest multidisciplinary teamwork as a proper approach in the treatment of such injuries. (+info)