RESUMEN
Cultivating a more dynamic relationship between science and policy is essential for responding to complex social challenges such as sustainability. One approach to doing so is to "span the boundaries" between science and decision making and create a more comprehensive and inclusive knowledge exchange process. The exact definition and role of boundary spanning, however, can be nebulous. Indeed, boundary spanning often gets conflated and confused with other approaches to connecting science and policy, such as science communication, applied science, and advocacy, which can hinder progress in the field of boundary spanning. To help overcome this, in this perspective, we present the outcomes from a recent workshop of boundary-spanning practitioners gathered to (1) articulate a definition of what it means to work at this interface ("boundary spanning") and the types of activities it encompasses; (2) present a value proposition of these efforts to build better relationships between science and policy; and (3) identify opportunities to more effectively mainstream boundary-spanning activities. Drawing on our collective experiences, we suggest that boundary spanning has the potential to increase the efficiency by which useful research is produced, foster the capacity to absorb new evidence and perspectives into sustainability decision-making, enhance research relevance for societal challenges, and open new policy windows. We provide examples from our work that illustrate this potential. By offering these propositions for the value of boundary spanning, we hope to encourage a more robust discussion of how to achieve evidence-informed decision-making for sustainability.
RESUMEN
A spectrometer based on pulsed nanosecond laser-induced breakdown spectroscopy (LIBS) was employed for the quantitative determination of heavy and essential metals in salts from various sources available in Pakistan. Six salt samples were collected from sea salt and rock salt. Toxic metals (Cu, Cd, and Ni) and other microessentials (Fe, Ca, Co, Mg, Mn, S, and Zn) were investigated from the recorded spectra. The detection system was calibrated using a parametric dependence study. The quantitative analyses were accomplished under the assumption of local thermodynamic equilibrium and optically thin plasma. The results by the LIBS technique were in agreement with the outcomes of the same samples studied using a more standard approach like inductively coupled plasma-atomic emission spectroscopy (ICP-AES). When the concentrations of heavy and essential metals were calculated using a calibration-free LIBS method that does not need a standard salt specimen and dilution, both LIBS and ICP-AES were also in good agreement. The limit of detection of the experimental set up was determined for the observed heavy metals in the studied samples.
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OBJECTIVES: To assess the effectiveness of a scabies control programme in reducing the prevalence of scabies in urban Bangladesh madrasahs, where the condition is extremely common. STUDY DESIGN: A controlled trial involving four intervention madrasahs (total students 2359) and four control madrasahs (total students 2465) in Dhaka Metropolitan Area. METHODS: A baseline scabies sample survey was carried out on 40 and 44 students of four intervention and four control madrasahs, respectively. Another 40 students of the intervention madrasahs were administered a pre-intervention test on scabies knowledge. This was followed by mass treatment of all students, teachers and staff of the eight madrasahs with topical 5% permethrin cream. The subsequent intervention involved daily monitoring of students for five key personal hygiene practices, weekly 10-min scabies health education classes, supply of simple and inexpensive products to students to prevent cross-infestation to/from peers (e.g. plastic bags, clothes hangers), and chemotherapy of new students detected with scabies. After 4 months of the intervention, the prevalence of scabies, personal hygiene practices and scabies knowledge were assessed in students of the intervention madrasahs. RESULTS: Before the intervention, the prevalence of scabies was 61% and 62% in intervention and control madrasahs, respectively (P = 1.00). After mass scabies treatment in all eight madrasahs and 4 months of intervention, the prevalence of scabies was reduced to 5% and 50% in intervention and control madrasahs, respectively (P < 0.001). There were significant improvements in all five personal hygiene practices at the intervention madrasahs. Mean test scores for scabies knowledge were 40% before the intervention and 99% after the intervention in the four intervention madrasahs. The cost of this programme was US$1.60 per student, and primarily included products such as plastic bags and clothes hangers, and health education material. CONCLUSIONS: This programme demonstrates a pragmatic and cost-effective way to control scabies in a residential institutional setting. It is recommended that this programme should be scaled up to all residential madrasahs in Bangladesh.
Asunto(s)
Religión , Escabiosis/prevención & control , Servicios de Salud Escolar/organización & administración , Instituciones Académicas , Salud Urbana/estadística & datos numéricos , Adolescente , Bangladesh/epidemiología , Niño , Femenino , Estudios de Seguimiento , Educación en Salud , Conocimientos, Actitudes y Práctica en Salud , Humanos , Higiene/normas , Masculino , Permetrina/uso terapéutico , Prevalencia , Evaluación de Programas y Proyectos de Salud , Escabiosis/tratamiento farmacológico , Escabiosis/epidemiología , Estudiantes/psicología , Estudiantes/estadística & datos numéricosRESUMEN
STUDY DESIGN: In order to study the role of gender in recovery, we induced a thoracic compression spinal cord injury (SCI) separately in 2-month-old male and female C57Bl/6 mice. OBJECTIVES: We intended to assess effects of gender on recovery of hindlimb motor function and to correlate these with histomorphologic profiles of injured spinal cord tissue. METHODS: Locomotor function was evaluated by three means: a modified locomotor scoring system for rodents, beam walking and computerized activity meter. Histology was analyzed by comparison of hematoxylin and eosin-stained perfused specimens. RESULTS: Locomotor scores were 2.2+/-0.9 on day 1 in male mice, while, in contrast, they were significantly higher, 7.3+/-1.7, in females (P<0.02). On day 14 Basso, Beattie and Bresnahan scores were 9.5+/-2.2 in male mice and 16.0+/-2.2 in females (P<0.03). Terminal histology showed that the spinal cord architecture was relatively better preserved in female mice and that the extent of necrosis and infiltration of inflammatory cells was less compared to males. SETTING: Neurobiology Research Laboratory of University of Kansas Medical School in US Department of Veterans Affairs Medical Center, Kansas City, Missouri. CONCLUSION: We found that the severity of the initial injury as well as the ultimate recovery of motor function after SCI is significantly influenced by gender, being remarkably better in females. The mechanism(s) of neuroprotection in females, although not yet elucidated, may be associated with the effects of estrogen on pathophysiological processes (blood flow, leukocyte migration inhibition, antioxidant properties, and inhibition of apoptosis). SPONSORSHIP: Medical Research, US Department of Veterans Affairs, the Christopher Reeve Paralysis Foundation and NIH.
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Actividad Motora/fisiología , Recuperación de la Función/fisiología , Caracteres Sexuales , Traumatismos de la Médula Espinal/fisiopatología , Animales , Modelos Animales de Enfermedad , Femenino , Miembro Posterior/fisiopatología , Masculino , Ratones , Ratones Endogámicos C57BL , Examen Neurológico , Desempeño Psicomotor/fisiología , Índice de Severidad de la Enfermedad , Traumatismos de la Médula Espinal/patología , Factores de TiempoRESUMEN
STUDY DESIGN: Functional outcome was evaluated following experimental compression-type spinal cord injury (SCI) in wild-type mice and knockout mice, lacking the inducible nitric oxide synthase (iNOS) gene. OBJECTIVES: To evaluate the role of the nitric oxide generating enzyme iNOS in SCI. METHODS: The experimental animals were subjected to an extradural compression of the thoracic spinal cord. Functional outcome was studied during the first 2 weeks post-injury using a scoring system for assessment of hind limb motor function. RESULTS: Injury resulted in initial paraplegia followed by gradual improvement of motor function in most cases. Mice lacking the iNOS gene (iNOS-/-) clearly tended to have a better functional outcome than wild-type mice. The difference was significant on day 14 after injury. CONCLUSION: In accordance with a few earlier experimental studies, showing beneficial effects of pharmacological iNOS inhibition, the present report would indicate a destructive influence of iNOS following spinal cord trauma.
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Trastornos Neurológicos de la Marcha/diagnóstico , Trastornos Neurológicos de la Marcha/fisiopatología , Miembro Posterior/fisiopatología , Óxido Nítrico Sintasa/deficiencia , Recuperación de la Función/fisiología , Compresión de la Médula Espinal/diagnóstico , Compresión de la Médula Espinal/fisiopatología , Médula Espinal/fisiopatología , Animales , Femenino , Trastornos Neurológicos de la Marcha/etiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Óxido Nítrico Sintasa de Tipo II , Médula Espinal/patología , Compresión de la Médula Espinal/patologíaRESUMEN
We have previously demonstrated that mice deficient in ICAM-1 and P-selectin (ICAM-1/PS-/-) have improved functional recovery after spinal cord injury (SCI), compared to injured controls. In this study the spinal cords from wild-type and ICAM-1/PS-/- mice were evaluated histopathologically 14 days after severe compression-type SCI. Following injury there was an atrophy of the spinal cord. Significant sparing of total cross-sectional area was noted in ICAM-1/PS-/- mice compared to injured controls at the site of compression and in the distal peri-injury zone. Likewise, significant preservation of white matter area, as measured by Luxol staining, was found in mutant mice at the site of injury and in the proximal peri-injury zone. Gray matter damage was investigated by microtubule-associated protein 2 immunohistochemistry. Following severe SCI, a trend of gray matter sparing was noticed in ICAM-1/PS-/- animals. Quantitation of iba1 immunohistochemistry revealed that microglial reaction was significantly suppressed in the mutant animals. Astroglial reaction, visualized by GFAP immunostaining, did not differ between groups. Our results indicate that ICAM-1 and P-selectin are involved in autodestructive events provoked by the initial injury but the precise underlying mechanisms remain obscure.
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Gliosis/metabolismo , Inflamación/metabolismo , Molécula 1 de Adhesión Intercelular/metabolismo , Fibras Nerviosas Mielínicas/metabolismo , Selectina-P/metabolismo , Traumatismos de la Médula Espinal/metabolismo , Médula Espinal/metabolismo , Animales , Atrofia/patología , Proteínas de Unión al Calcio/metabolismo , Colorantes , Femenino , Proteína Ácida Fibrilar de la Glía/metabolismo , Gliosis/genética , Gliosis/patología , Inmunohistoquímica , Indoles , Inflamación/genética , Inflamación/patología , Molécula 1 de Adhesión Intercelular/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas de Microfilamentos , Microglía/metabolismo , Microglía/patología , Proteínas Asociadas a Microtúbulos/metabolismo , Fibras Nerviosas Mielínicas/patología , Neutrófilos/inmunología , Neutrófilos/metabolismo , Neutrófilos/patología , Selectina-P/genética , Médula Espinal/patología , Médula Espinal/fisiopatología , Traumatismos de la Médula Espinal/genética , Traumatismos de la Médula Espinal/patología , Degeneración Walleriana/patologíaRESUMEN
STUDY DESIGN: It is well known that changes of the body temperature as well as trauma influence the blood flow in the brain and spinal cord. However, there is still a lack of knowledge concerning the levels of blood flow changes, especially during hypothermia. OBJECTIVES: This investigation was carried out to examine the effects of systemic hypothermia and trauma on spinal cord blood flow (SCBF). METHODS: Twenty-four rats were randomized either to thoracic laminectomy only (Th VII-IX) or to 35 g spinal cord compression trauma. The animals were further randomized to either constant normothermia (38 degrees C) or to a systemic cooling procedure, ie reduction of the esophageal temperature from 38 to 30 degrees C. SCBF was recorded 5 mm caudal to the injury zone using Laser-Doppler flowmetry which allows a non-invasive continuous recording of local changes in the blood flow. The autoregulation ability was tested at the end of the experiments by inducing a 30-50 mmHg blood-pressure fall, using blood-withdrawal from the carotid artery. RESULTS: The mean SCBF decreased 2.8% and 3.5% per centigrade reduction of esophageal temperature in the animals sustained to hypothermia with and without trauma, respectively. This could be compared to a decrease of 0.2%/min when only trauma was applied. No significant differences were seen between the groups concerning auto regulatory ability. CONCLUSIONS: Our results indicate that the core temperature has a high impact on the SCBF independent of previous trauma recorded by Laser-Doppler flowmetry. This influence exceeds the response mediated by moderate compression trauma alone.
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Hipotermia/fisiopatología , Compresión de la Médula Espinal/etiología , Compresión de la Médula Espinal/fisiopatología , Traumatismos de la Médula Espinal/complicaciones , Médula Espinal/irrigación sanguínea , Animales , Presión Sanguínea , Laminectomía , Flujometría por Láser-Doppler , Masculino , Ratas , Ratas Sprague-Dawley , Flujo Sanguíneo Regional , Médula Espinal/cirugíaRESUMEN
Wild-type mice and mice lacking nitric oxide synthase (NOS) of neuronal type or TNF-alpha were subjected to an extradural compression of the thoracic spinal cord. The functional outcome of the hind limbs was assessed by using a motor function score (MFS). The injury resulted in paraplegia of the hind limbs in wild-type mice at day 1 after injury. Gradual recovery was observed during the following 14 days. Injured NOS -/- animals had an improved hind limb motor function during the entire observation period compared to wild-type controls. The difference was statistically significant on day 10 (p < 0.022) and day 14 (p < 0.048) after injury. At the site of injury, there was a trend of gray matter preservation in NOS -/- mice, as measured by MAP2 staining (p < 0.077). Injured mice lacking TNF-alpha had the lowest motor score among all the groups on day 1. During the following period, they had motor scores similar to those of wild-type controls and there was no significant difference at any time point. TNF-alpha -/- animals showed a trend of decreased white matter preservation compared to wild-type animals (p < 0.097). Our study shows that after spinal cord injury, mice lacking NOS have a better functional ability of their hind limbs than controls with the same degree of injury. This would indicate that the functional outcome is influenced in a negative way in wild mice by the presence of NO. The degree of secondary damage to the spinal cord might be attenuated in NOS-deficient mice.
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Óxido Nítrico Sintasa/deficiencia , Óxido Nítrico/metabolismo , Recuperación de la Función/fisiología , Traumatismos de la Médula Espinal/metabolismo , Factor de Necrosis Tumoral alfa/deficiencia , Animales , Colorantes , Modelos Animales de Enfermedad , Femenino , Proteína Ácida Fibrilar de la Glía/metabolismo , Gliosis/metabolismo , Gliosis/patología , Gliosis/fisiopatología , Indoles , Ratones , Ratones Noqueados/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Trastornos del Movimiento/etiología , Trastornos del Movimiento/patología , Trastornos del Movimiento/fisiopatología , Degeneración Nerviosa/metabolismo , Degeneración Nerviosa/patología , Degeneración Nerviosa/fisiopatología , Óxido Nítrico Sintasa/genética , Médula Espinal/metabolismo , Médula Espinal/patología , Médula Espinal/fisiopatología , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/fisiopatología , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Denatured muscle autograft contains large inner basement membrane tubes, which are anatomically and chemically similar to peripheral nerve basement membrane tubes. These autografts can be used for bridging nerve gaps. In 30 Duncan-Hartley guinea pig sciatic nerves, experimentally induced gaps of 5 mm, 10 mm, and 15 mm were bridged with freeze-thawed gluteus maximus muscle autografts. The results were studied for up to 12 weeks. Functional and histological criteria, morphometry, and electron microscopy were used for the evaluation of regeneration and myelination. Functional recovery was seen by 12 weeks in 5-mm grafts. Morphometric study of 1-microm semithin sections was carried out, and the number of axons in each representative field was studied, as the percentage of myelinated and unmyelinated fibers; the thickness of myelin was also measured. The percentage of myelinated and unmyelinated fibers was estimated by transmission electron microscopy (TEM). Axonal repopulation in the distal segment was seen by the third week in the 5-mm graft, and myelination was more extensive in this group in comparison to the others. On morphometric analysis, the mean fiber diameter in the distal part of the graft was 3.81 microm in the 5-mm graft and 2.9 microm in the 15-mm graft at 12 weeks. The results of this experiment prove that the length of the graft is an important consideration for muscle autografts when they are used for mixed peripheral nerve repair.
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Músculo Esquelético/trasplante , Regeneración Nerviosa , Animales , Cobayas , Fibras Musculares Esqueléticas/ultraestructura , Músculo Esquelético/ultraestructura , Vaina de Mielina , Nervio Ciático/lesiones , Nervio Ciático/fisiologíaRESUMEN
Systemic hypothermia has been shown to exert neuroprotective effects in experimental ischemic CNS models caused by vascular occlusions. The present study addresses the question as to whether systemic hypothermia has similar neuroprotective qualities following severe spinal cord compression trauma using microtubule-associated protein 2 (MAP2) immunohistochemistry combined with the avidin-biotin-peroxidase complex method as marker to identify neuronal and dendritic lesions. Fifteen rats were randomized into three equally sized groups. One group sustained thoracic laminectomy, the others severe spinal cord compression trauma of the T8-9 segment. The control group contained laminectomized animals submitted to a hypothermic procedure in which the esophageal temperature was reduced from 38 degrees C to 30 degrees C. The two trauma groups were either submitted to the same hypothermic procedure or kept normothermic during the corresponding time. All animals were sacrificed 24 h following the surgical procedure. The MAP2 immunostaining in the normothermic trauma group indicated marked reductions in MAP2 antigen in the cranial and caudal peri-injury zones (T7 and T10, respectively). This reduction was much less pronounced in the hypothermic trauma group. In fact, the MAP2 antigen was present in almost equally sized areas in both the hypothermic groups independent of previous laminectomy alone or the addition of trauma. Our study thus indicates that hypothermia has a neuroprotective effect on dendrites of rat spinal cords subjected to compression trauma.
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Hipotermia/etiología , Compresión de la Médula Espinal/complicaciones , Animales , Temperatura Corporal , Dendritas/patología , Hipotermia/fisiopatología , Inmunohistoquímica , Masculino , Proteínas Asociadas a Microtúbulos/metabolismo , Ratas , Ratas Sprague-Dawley , Médula Espinal/patología , Compresión de la Médula Espinal/metabolismo , Compresión de la Médula Espinal/patologíaRESUMEN
Systemic hypothermia exerts neuroprotective effects following trauma and ischemia caused by vascular occlusion in the brain. In the spinal cord similar effects have been demonstrated following ischemia after aortic occlusion. We have previously presented protective effects on several morphological parameters in the early period after the injury, using an established spinal cord compression injury model and systemic hypothermia. In the present study we have evaluated the effects on motor function following severe spinal cord compression trauma and treatment with moderate systemic hypothermia. Thirty Sprague Dawley rats were randomized into three groups: In group 1 (n = 4), the animals underwent a hypothermic procedure, including a 2 h hypothermic period with a body temperature of 30 degrees C, following the initial laminectomy. In group 2 (n = 12) a 50 g compression was applied to the spinal cords for 5 min, after which the animals were kept under normothermic anesthesia for 3 h. In group 3 (n = 14), the animals underwent the same trauma procedure as in group 2 and the same hypothermic procedure as in group 1. The animals were allowed to survive for 14 days, during which the motor function was recorded. This degree of trauma results in a non-reversible paraplegia, and the addition of systemic hypothermia as described above did not alter the neurological recovery as measured by two different methods of recording the motor function up to two weeks after injury. All animals survived in group 1. However, the mortality rates in group 2 were 25% and in group 3, 50%, respectively, which mirrors the severity of the trauma. The application of systemic hypothermia and the lack of experimental therapeutic success highlight the difficulties of transferring experimental beneficial neuroprotective effects to a clinically useful treatment method. In this experimental set-up the effects of the severe primary injury may overshadow the effects of the secondary injury mechanisms, which limits the therapeutic possibilities of systemic hypothermic treatment.
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Hipotermia Inducida , Traumatismos de la Médula Espinal/fisiopatología , Traumatismos de la Médula Espinal/terapia , Animales , Peso Corporal , Masculino , Actividad Motora , Sistema Nervioso/fisiopatología , Paraplejía/etiología , Ratas , Ratas Sprague-Dawley , Traumatismos de la Médula Espinal/complicaciones , Traumatismos de la Médula Espinal/patología , Análisis de Supervivencia , Insuficiencia del Tratamiento , Resultado del TratamientoRESUMEN
The purpose of this study was to develop a spinal cord injury model in the mouse. Various degrees of extradural compression were used to induce mild, moderate or severe compression injuries. Furthermore, a locomotor rating scale was developed by which the functional outcome of the spinal cord injury could be assessed. The introduction of such a model will be useful for further studies on the pathogenesis and treatment strategies of spinal cord injury. To assess hindlimb motor function, a 10-point scale was used. Initially, the animals were allowed to move freely in an open field and were rated 0-5, 0 being no movement and 5 being almost normal. Animals scoring a 5 were then assessed using steel bars with decreasing widths from 2 cm to 5 mm. For each bar successfully crossed over, they gained additional points. Before injury the hindlimb motor function score (MFS) in all the animals was 10. In mice with mild compression, MFS was decreased slightly on day 1 and recovered to 9 +/- 0.6 on day 14. For mice with moderate compression, the MFS decreased to 4.6 +/- 0.4 on day 1 after injury and gradually improved to 8.1 +/- 0.6 on day 14. Severe injury resulted in paraplegia of the hindlimbs day 1 after injury with a score of 0.6 +/- 0.2. By day 14 after injury, these animals gradually recovered to 3.9 +/- 0.1, could bear the weight on the hindlimbs and walk with a severe deficit. There was a 3%, 9% and 19% decrease in the total cross-sectional area of the spinal cord 14 days after mild, moderate and severe injury, respectively. Microtubule-associated protein immunostaining revealed that the gray matter decreased to 61 +/- 7% in moderately injured animals, while severe compression resulted in a complete loss of gray matter. White matter decreased to 86 +/- 6% in moderately injured animals and 29 +/- 11% in severely injured animals. This study shows that the mouse can be used to achieve reproducible spinal cord compression injuries of various degrees of severity. The force of the impact correlates well with the neurological and light microscopic outcome. The motor function test presented in this paper and the computerized quantification of tissue damage can be used to evaluate the efficacy of different treatment strategies.
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Modelos Animales de Enfermedad , Trastornos Neurológicos de la Marcha/fisiopatología , Ratones Endogámicos/lesiones , Paraplejía/fisiopatología , Compresión de la Médula Espinal/fisiopatología , Animales , Femenino , Trastornos Neurológicos de la Marcha/clasificación , Trastornos Neurológicos de la Marcha/patología , Miembro Posterior/inervación , Miembro Posterior/fisiopatología , Ratones , Ratones Endogámicos/metabolismo , Actividad Motora/fisiología , Degeneración Nerviosa/metabolismo , Degeneración Nerviosa/patología , Degeneración Nerviosa/fisiopatología , Neuronas/metabolismo , Neuronas/patología , Paraplejía/clasificación , Paraplejía/patología , Recuperación de la Función/fisiología , Reflejo/fisiología , Médula Espinal/metabolismo , Médula Espinal/patología , Médula Espinal/fisiopatología , Compresión de la Médula Espinal/clasificación , Compresión de la Médula Espinal/patología , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/fisiopatología , Factores de TiempoRESUMEN
This immunohistochemical study evaluated Fas and Fas ligand (FasL) in the rat nervous system and their changes in the spinal cord subjected to compression. Normal spinal cord showed a low level of Fas and FasL immunoreactivity in the white matter except in the corticospinal tracts. Fas and FasL immunoreactivity seemed to be located in axons and their myelin sheaths. Other regions of the nervous system did not show immunoreactivity to Fas and FasL. Moderate and severe compression injury of the spinal cord resulted in a reduction of Fas and FasL immunoreactivity in the white matter of injured T8-9 segments at 4 h and a complete loss at 1 day after trauma. This was seen even in the remaining white matter. In contrast, increased immunoreactivity to Fas and FasL was present in the cranial T7, caudal T10 (moderate injury) and T12 (severe injury) segments at day 4 with most intense staining were seen at day 9 after trauma. Increased Fas and FasL immunoreactivity may have pathophysiological implications for the development of secondary injuries after trauma to the spinal cord. Fas-FasL interactions may for instance be involved in apoptosis of oligodendrocytes which occurs as a delayed phenomenon after trauma to the spinal cord. The integrity of myelin sheaths may in this way be jeopardized by apoptosis of oligodendrocytes.
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Glicoproteínas de Membrana/metabolismo , Compresión de la Médula Espinal/metabolismo , Compresión de la Médula Espinal/patología , Médula Espinal/metabolismo , Médula Espinal/patología , Receptor fas/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/patología , Encéfalo/fisiopatología , Proteína Ligando Fas , Masculino , Glicoproteínas de Membrana/inmunología , Neuronas/inmunología , Neuronas/metabolismo , Neuronas/patología , Sistema Nervioso Periférico/metabolismo , Sistema Nervioso Periférico/patología , Sistema Nervioso Periférico/fisiopatología , Ratas , Ratas Sprague-Dawley , Médula Espinal/fisiopatología , Compresión de la Médula Espinal/fisiopatología , Factores de Tiempo , Receptor fas/inmunologíaRESUMEN
Adhesion molecule-mediated adhesion and extravasation of leukocytes may constitute a mechanism of secondary tissue damage following spinal cord injury (SCI). The objective of the present study was to determine to what extent genetic deficiency in the adhesion molecule ICAM-1 influences functional and histopathological measures of outcome following SCI. ICAM-1-/- (n = 11) and wild-type (n = 9) mice were subjected to a compression-type SCI. Assessment of hind-limb motor function was done on days 1, 2, 4, 7, 10, and 14 after injury, using a motor function scoring system. Injury resulted in a drastically impaired hind limb motor function at day one after injury followed by a partial recovery during the observation period. No significant functional differences were found between the experimental groups at any time-point. Fourteen days after injury the animals were sacrificed and the spinal cords were processed for histopathological and immunohistochemical evaluation. Luxol-stained, MAP2-, GFAP- and iba-1-immunostained cross-sectional areas were quantitated using a computerized image analysis system to investigate white matter damage, neuronal loss, astrocytic response and microglial activation respectively. None of these parameters differed significantly between the groups. Separate experiments revealed that the early (24 h postinjury) infiltration of polymorphonuclear leukocytes was significantly reduced in white matter but not in the grey matter of ICAM-1-/- mice, compared to injured controls. In summary, these results do not support the concept that ICAM-1 alone mediates secondary tissue damage following traumatic SCI in the mouse.
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Molécula 1 de Adhesión Intercelular/fisiología , Traumatismos de la Médula Espinal/fisiopatología , Médula Espinal/patología , Animales , Proteínas de Unión al Calcio/análisis , Femenino , Proteína Ácida Fibrilar de la Glía/análisis , Molécula 1 de Adhesión Intercelular/análisis , Molécula 1 de Adhesión Intercelular/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas de Microfilamentos , Proteínas Asociadas a Microtúbulos/análisis , Actividad Motora , Traumatismos de la Médula Espinal/genética , Traumatismos de la Médula Espinal/patología , Factores de Tiempo , Heridas no Penetrantes/genética , Heridas no Penetrantes/patología , Heridas no Penetrantes/fisiopatologíaRESUMEN
We compared two staining methods for the demonstration of dendrites under normal and pathological conditions of the rat central nervous system. MAP2- and neurogranin immunohistochemistry was applied to samples from normal tissue, spinal cord subjected to graded compression trauma, cerebral cortex following contusion trauma, and brains with focal ischemic lesions induced by occlusion of the middle cerebral artery (MCAO). Normal rats showed MAP2 immunoreactivity in nerve cell bodies and dendrites of brain and spinal cord. However, neurogranin staining was present only in nerve cell bodies and dendrites of the normal brain, and not in the spinal cord. Reduction of MAP2 immunoreactivity was seen in lesions of spinal cords subjected to compression trauma. Neurogranin staining was of no value in this experimental condition since it was not present under normal conditions. The brain contusions showed loss of both MAP2- and neurogranin immunoreactivity at the site of the lesion. MCAO resulted in an extensive loss of MAP2- and neurogranin staining in the ipsilateral hemisphere. In conclusion, our study shows that MAP2 immunostaining is a sensitive method for identifying dendritic lesions of various CNS injuries in the rat. Neurogranin immunostaining is an alternative method for investigations of dendritic pathology in the brain but not in the spinal cord.
Asunto(s)
Proteínas de Unión a Calmodulina/análisis , Sistema Nervioso Central/lesiones , Sistema Nervioso Central/patología , Dendritas/química , Dendritas/patología , Proteínas Asociadas a Microtúbulos/análisis , Proteínas del Tejido Nervioso/análisis , Animales , Biomarcadores/análisis , Lesiones Encefálicas/metabolismo , Lesiones Encefálicas/patología , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Sistema Nervioso Central/química , Inmunohistoquímica , Masculino , Neurogranina , Distribución Normal , Ratas , Ratas Sprague-Dawley , Traumatismos de la Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/patologíaRESUMEN
We evaluated by in situ nick end labeling the presence of apoptotic glial cells in the spinal cord of rats which have sustained a moderate and severe compression injury at the level of T8-9, resulting in a severe but reversible paraparesis and irreversible paraplegia, respectively. In a previous investigation we found apoptotic glial cells (oligodendrocytes) in the immediate vicinity of the primary lesion (T7 and T10). The present study was designed to evaluate the extent of such cells in the spinal cord even at long distances away from the primary injury. Rats sustaining a moderate and severe compression injury and surviving 4 and 9 days showed a significant increase in the number of apoptotic glial cells at the T1, T5, T7, T12 and L2 levels. At the T10 level the elevation was significant only after day 9. There was no significant increase in the number of these cells at 4 h and 1 day after moderate and severe compression. In general, the apoptotic cells were most often seen in segments adjacent to the compression. They were randomly located in the ventral, lateral and dorsal tracts but were rarely present in the gray matter of the cord. In conclusion, compression trauma to rat spinal cord induces signs of apoptosis in glial cells, presumably oligodendrocytes of the long tracts. This newly discovered type of secondary injury is widely distributed in the damaged spinal cord and occurs even at long distances remote from the initial compression injury. Apoptotic cell death of oligodendrocytes will induce myelin degeneration and cause additional disturbances of axonal function. This cell damage may be a target for future therapy since it occurs after a delay and chemical compounds are now available by which apoptotic cell death can be modified.
Asunto(s)
Apoptosis/fisiología , Oligodendroglía/patología , Compresión de la Médula Espinal/patología , Médula Espinal/patología , Precursor de Proteína beta-Amiloide/análisis , Animales , Modelos Animales de Enfermedad , Inmunohistoquímica , Indoles , Masculino , Ratas , Médula Espinal/fisiopatología , Compresión de la Médula Espinal/fisiopatología , Factores de TiempoRESUMEN
STUDY DESIGN: Systemic hypothermia exerts neuroprotective effects in experimental ischemic CNS models caused by vascular occlusions. Recent experimental and clinical studies have also demonstrated beneficial effects of hypothermic treatment following brain trauma. OBJECTIVES: The present study addresses the question as to whether systemic hypothermia has similar protective qualities following severe spinal cord compression trauma using beta-APP-, ubiquitin-, and PGP-9.5-immunohistochemistry combined with the ABC complex method as markers to identify axonal changes. METHODS: Fifteen rats were randomized into three equally large groups and sustained to either thoracic laminectomy or to severe spinal cord compression trauma of the Th 8 - 9 segments. The non-trauma group contained laminectomized animals submitted to a hypothermic procedure in which the core temperature was reduced from 38 to 30 degrees C. The two trauma groups were either submitted to the same hypothermic procedure or kept normothermic during the corresponding time. All animals were sacrificed 24 h following the surgical procedure. RESULTS: In the hypothermic non-trauma group no axonal changes were seen. The number of abnormal axons, as indicated by accumulation of immunoreactive material in enlarged axons, was lower in the peri-injury zones of the hypothermic trauma group than in the normothermic trauma group. This difference was most obvious in the cranial peri-injury zones. No differences were seen between the groups in the trauma zones. CONCLUSIONS: This study demonstrates reduced axonal swelling in the peri-injury zones of spinal cord injured rats treated with systemic hypothermia. These changes could either indicate neuroprotective effects of the hypothermic treatment, or be results of reduced axonal transport or protein synthesis. To evaluate the clinical importance of our findings, further studies including reliable outcome measures of the animals must be performed.
Asunto(s)
Precursor de Proteína beta-Amiloide/análisis , Axones/patología , Compresión de la Médula Espinal/patología , Médula Espinal/patología , Tioléster Hidrolasas/análisis , Ubiquitinas/análisis , Animales , Temperatura Corporal/fisiología , Hipotermia Inducida , Inmunohistoquímica , Masculino , Ratas , Ratas Sprague-Dawley , Compresión de la Médula Espinal/fisiopatología , Factores de Tiempo , Ubiquitina TiolesterasaRESUMEN
Systemic hypothermia has neuroprotective effects in experimental models of central nervous system ischemia caused by vascular occlusions. The present study addresses the question as to whether systemic hypothermia can influence the extravasation of plasma proteins following severe spinal cord compression trauma using immunohistochemistry to identify the plasma proteins albumin, fibrinogen and fibronectin. Fifteen rats were assigned to one of three groups and received either thoracic (T) laminectomy or severe spinal cord compression trauma of the T8-9 segment. One group comprised laminectomized animals without compression trauma submitted to a hypothermic procedure in which the core temperature was reduced from 38 degrees to 30 degrees C. The two trauma groups were either submitted to the same hypothermic procedure or kept normothermic during the corresponding time. All animals were killed 24 h following the surgical procedure. The normothermic and hypothermic trauma groups had indications of marked extravasation of albumin, fibrinogen and fibronectin at the site of the injury (T8-9). There was also pronounced extravasation in the cranial and caudal peri-injury zones (T7 and T10) of normothermic injured rats but, with few exceptions, not in the hypothermic ones with the same degree of compression. By measuring the cross-sectional area of the peri-injury zones we found in the hypothermic trauma group a significant reduction of the expansion compared with that present in normothermic injured rats. Our study thus indicates that hypothermia reduces the extravasation of the plasma proteins albumin, fibrinogen and fibronectin following spinal cord compression in the rat. Such a reduction may contribute to neuroprotective effects exerted by hypothermia.
Asunto(s)
Proteínas Sanguíneas/metabolismo , Exudados y Transudados/metabolismo , Hipotermia Inducida , Traumatismos de la Médula Espinal/metabolismo , Animales , Fibrinógeno/metabolismo , Fibronectinas/metabolismo , Inmunohistoquímica , Masculino , Compresión Nerviosa , Ratas , Ratas Sprague-Dawley , Albúmina Sérica/metabolismo , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/terapiaRESUMEN
Clomethiazole (CMZ) has a neuroprotective effect in experimental focal and global forebrain ischemia. This neuroprotective effect may depend on its ability to enhance GABA receptor activity. We have studied the effect of pretreatment with CMZ on motor function recovery and nerve cell damage after spinal cord injury (SCI). Rats were randomized and 30 min before SCI they received a single intraperitoneal dose of CMZ (150 mg/kg) or saline. The spinal cord was injured with a 50 g (4.5 g/mm2) load, applied over the exposed dura, through a curved rectangular plate (2.2 x 5.0 mm) for 5 min at T8-9. The animals became paraplegic 1 day after injury. The rats were evaluated for recovery of hind limb motor function. All animals recovered to some extent over the observation period of 12 weeks. However, hind limb motor function was significantly better in the animals pretreated with CMZ. At 12 weeks the rats were killed and perfused/fixed for morphological investigations. Microtubule-associated protein 2 (MAP2) immunostaining was used to stain neurons and dendrites and Luxol-fast blue to stain myelinated tracts of the white matter. The injured segment of the spinal cord showed severe atrophy, distortion, cavitation and necrosis of grey and white matter. Compared to uninjured controls the transverse sectional area was reduced to 32.7 +/- 4% in untreated animals but only to 38.5% +/- 4.1 in CMZ-treated animals. MAP2 staining showed that, compared to uninjured controls, grey matter was reduced to 7.4 +/- 2.7% in saline-treated injured animals and to 22.7 +/- 5.4% in CMZ-treated rats. Our results thus show that in this model CMZ improves hind limb motor function and attenuates the morphological damage to the spinal cord.
Asunto(s)
Clormetiazol/uso terapéutico , Miembro Posterior/fisiología , Actividad Motora/efectos de los fármacos , Fármacos Neuroprotectores/uso terapéutico , Traumatismos de la Médula Espinal/tratamiento farmacológico , Traumatismos de la Médula Espinal/fisiopatología , Animales , Colorantes , Proteína Ácida Fibrilar de la Glía/metabolismo , Inmunohistoquímica , Indoles , Masculino , Proteínas Asociadas a Microtúbulos/metabolismo , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/patología , Compresión Nerviosa , Ratas , Ratas Sprague-Dawley , Recuperación de la Función/efectos de los fármacos , Traumatismos de la Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/patologíaRESUMEN
We have performed an immunohistochemical study on the expression of the adhesion molecules ICAM-1 and CD11b 1 h to 1 week following a compression injury to the rat spinal cord. The spinal cord of control animals showed ICAM-1 expression in some vessels and in the leptomeninges. Mechanical compression of the spinal cord induced an endothelial upregulation of ICAM-1 that was maximal in rats surviving 1-2 days after injury. This reaction was seen at the center of the lesion as well as in the perifocal zones. Apart from the endothelial upregulation, increased ICAM-1 expression also was found in leptomeningeal and ependymal cells of traumatized animals. In control animals resting microglial cells were moderately CD11b immunoreactive. Trauma induced a rapid microglial upregulation of CD11b in the white matter that was evident even at 1 h after injury. By 1 day to 1 week posttrauma conformational changes consistent with microglial activation, i.e., transformation into phagocytic microglial cells, were seen in the white matter. In the gray matter, CD11b immunohistochemistry revealed massive infiltration of phagocytic microglial cells and macrophages in animals surviving 1 day to 1 week. Intravascular and infiltrating leukocytes were intensely CD11b immunopositive. As reflected by CD11b immunohistochemistry, the maximal infiltration of polymorphonuclear leukocytes occurred at 2 days after the insult. Endothelial upregulation of ICAM-1 facilitates adhesion and extravasation of leukocytes by binding to the counterreceptor CD11b. Knowledge regarding the expression and cellular distribution of such molecules after central nervous system trauma is important since inflammatory mechanisms have been suggested to be involved in secondary neurological damage and thus constitute potential targets of therapy.