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1.
Childs Nerv Syst ; 38(10): 1999-2003, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35389065

RESUMEN

Anaplastic gangliogliomas (AGG) are rare tumors of the central nervous system (CNS) that commonly affect children and young adults, with an unusual infratentorial presentation, which is related to hydrocephalus and a worse prognosis. We report a case of a brainstem AGG in a 2-year-old boy who underwent a ventriculoperitoneal shunting (VPS) and later presented peritoneal metastasis. We also reviewed the related literature. Even though rare, disease dissemination through VPS should be sought in patients with CNS tumors and VPS who develop new abdominal symptoms. The early diagnosis and intervention may minimize morbidity and improve quality of life of such patients.


Asunto(s)
Neoplasias Encefálicas , Neoplasias del Sistema Nervioso Central , Ganglioglioma , Hidrocefalia , Neoplasias Peritoneales , Neoplasias Encefálicas/complicaciones , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/cirugía , Tronco Encefálico/patología , Neoplasias del Sistema Nervioso Central/cirugía , Niño , Preescolar , Ganglioglioma/complicaciones , Ganglioglioma/diagnóstico por imagen , Ganglioglioma/cirugía , Humanos , Hidrocefalia/cirugía , Masculino , Neoplasias Peritoneales/complicaciones , Neoplasias Peritoneales/diagnóstico por imagen , Neoplasias Peritoneales/cirugía , Calidad de Vida , Derivación Ventriculoperitoneal/efectos adversos
2.
Neurosurg Focus ; 48(6): E12, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32480373

RESUMEN

OBJECTIVE: The authors sought to evaluate clinical and laboratory data from pituitary adenoma (PA) patients with functioning PA (associated with acromegaly [n = 10] or Cushing disease [n = 10]) or nonfunctioning PA (NFPA; n = 10) that were classified according to 2017 WHO criteria (based on the expression of the transcription factors pituitary-specific positive transcription factor 1 [Pit-1], a transcription factor member of the T-box family [Tpit], and steroidogenic factor 1 [SF-1]) and to assess the immunostaining results for growth hormone (GH) and adrenocorticotropic hormone (ACTH) in the corresponding tumors. METHODS: Clinical and laboratory data were collected retrospectively. The percentage of tumoral cells positive for Pit-1, Tpit, or SF-1 was assessed and ImageJ software was used to evaluate immunopositivity in PAs with 2 different antibodies against GH (primary antibody 1 [AbGH-1] and primary antibody 2 [AbGH-2]) and 2 different antibodies against ACTH (primary antibody 1 [AbACTH-1] and primary antibody 2 [AbACTH-2]). RESULTS: Cells with positive Pit-1 staining were more frequently observed in lesions from patients with acromegaly (acromegaly group) than in lesions from patients with Cushing disease (Cushing group; p < 0.001) and those from patients with NFPA (NFPA group; p < 0.001). The percentage of Tpit-positive cells was higher in the Cushing group than in the acromegaly (p < 0.001) and NFPA (p < 0.001) groups. No difference was detected regarding SF-1 frequency among all groups (p = 0.855). In acromegalic individuals, GH immunostaining levels varied depending on the antibody employed, and only one of the antibodies (AbGH-2) yielded higher values in comparison with the values for NFPA patients (p < 0.001). For all of the antibodies employed, no significant correlations were detected between GH tissue expression and the laboratory data (serum GH vs AbGH-1, p = 0.933; serum GH vs AbGH-2, p = 0.853; serum insulin-like growth factor-1 [IGF-1] vs AbGH-1, p = 0.407; serum IGF-1 vs AbGH-2, p = 0.881). In the Cushing group data, both antibodies showed similar ACTH tissue expression, which was higher than that obtained in the NFPA group (p < 0.001). There were no significant associations between ACTH immunohistochemical findings and ACTH serum levels (serum ACTH vs AbACTH-1, p = 0.651; serum ACTH vs AbACTH-2, p = 0.987). However, ACTH immunostaining evaluated with AbACTH-1 showed a significant correlation with 24-hour urinary cortisol (24-hour cortisol vs AbACTH-1, p = 0.047; 24-hour cortisol vs AbACTH-2, p = 0.071). CONCLUSIONS: Immunostaining for Pit-1 and Tpit accurately identified lesions associated with acromegaly and Cushing disease, respectively. Conversely, SF-1 did not differentiate NFPA from lesions of the other two groups. Regarding hormonal tissue detection, results of the current investigation indicate that different antibodies may lead not only to divergent immunohistochemical results but also to lack of correlation with laboratory findings. Finally, PA classification based on transcription factor expression (Pit-1, Tpit, and SF-1), as proposed by the 2017 WHO classification of pituitary tumors, may avoid the limitations of PA classification based solely on digital immunohistochemical detection of hormones.


Asunto(s)
Acromegalia/clasificación , Adenoma/clasificación , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/clasificación , Neoplasias Hipofisarias/clasificación , Cuidados Preoperatorios/clasificación , Organización Mundial de la Salud , Acromegalia/sangre , Acromegalia/cirugía , Adenoma/sangre , Adenoma/cirugía , Hormona Adrenocorticotrópica/sangre , Adulto , Femenino , Hormona de Crecimiento Humana/sangre , Humanos , Factor I del Crecimiento Similar a la Insulina/metabolismo , Masculino , Persona de Mediana Edad , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/sangre , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/cirugía , Neoplasias Hipofisarias/sangre , Neoplasias Hipofisarias/cirugía , Cuidados Preoperatorios/métodos , Estudios Retrospectivos , Coloración y Etiquetado/clasificación , Coloración y Etiquetado/métodos
3.
Cell Mol Neurobiol ; 39(1): 149-160, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30539418

RESUMEN

Epilepsy is a common disease presenting with recurrent seizures. Hippocampal sclerosis (HS) is the commonest histopathological alteration in patients with temporal lobe epilepsy (TLE) undergoing surgery. HS physiopathogenesis is debatable. We have recently studied, by using mass spectrometry-based proteomics, an experimental model of TLE induced by electrical stimulation. Specifically, protein expressions of both the beta subunit of mitochondrial ATP synthase (ATP5B) and of membrane ATPases were found to be reduced. Here, we investigated tissue distribution of ATP5B and sodium/potassium-transporting ATPase subunit alpha-3 (NKAα3), a protein associated with neuromuscular excitability disorders, in human hippocampi resected "en bloc" for HS treatment (n = 15). We used immunohistochemistry and the stained area was digitally evaluated (increase in binary contrast of microscopic fields) in the hippocampal sectors (CA1-CA4) and dentate gyrus. All HS samples were classified as Type 1, according to the International League Against Epilepsy (ILAE) 2013 Classification (predominant cell loss in CA1 and CA4). ATP5B was significantly decreased in all sectors and dentate gyrus of HS patients compared with individuals submitted to necropsy and without history of neurological alterations (n = 10). NKAα3 expression showed no difference. Moreover, we identified a negative correlation between frequency of pre-operative seizures and number of neurons in CA1. In conclusion, our data showed similarity between changes in protein expression in a model of TLE and individuals with HS. ATP5B reduction would be at least in part due to neuronal loss. Future investigations on ATP5B activity could provide insights into the process of such cell loss.


Asunto(s)
Epilepsia/enzimología , Hipocampo/enzimología , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Esclerosis/enzimología , Adolescente , Adulto , Recuento de Células , Giro Dentado/patología , Epilepsia/patología , Femenino , Hipocampo/patología , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Neuronas/metabolismo , Neuronas/patología , Esclerosis/patología , ATPasa Intercambiadora de Sodio-Potasio , Adulto Joven
4.
Neurocirugia (Astur : Engl Ed) ; 33(5): 242-249, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36084960

RESUMEN

Primary intracranial malignant fibrous histiocytoma (MFH), or myxofibrosarcoma, is an extremely rare condition, with only a few cases reported in the literature. We report a case of a dural-based myxofibrosarcoma in a previously healthy 42-year-old man that was initially presumed to be an atypical meningioma. The findings based on conventional and advanced magnetic resonance sequences, including diffusion-weighted imaging, perfusion weighted imaging and proton magnetic resonance spectroscopy, as well as histopathological aspects, are discussed.


Asunto(s)
Neoplasias Encefálicas , Histiocitoma Fibroso Maligno , Neoplasias Meníngeas , Meningioma , Adulto , Neoplasias Encefálicas/diagnóstico por imagen , Histiocitoma Fibroso Maligno/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Neoplasias Meníngeas/diagnóstico por imagen , Neoplasias Meníngeas/patología , Meningioma/diagnóstico por imagen , Meningioma/patología
5.
Clin Case Rep ; 9(4): 2481-2482, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33936722

RESUMEN

Mycobacterium infection is a differential diagnosis to be considered in brain multifocal lesions with peripheral enhancement.

6.
Artículo en Inglés, Español | MEDLINE | ID: mdl-33875380

RESUMEN

Primary intracranial malignant fibrous histiocytoma (MFH), or myxofibrosarcoma, is an extremely rare condition, with only a few cases reported in the literature. We report a case of a dural-based myxofibrosarcoma in a previously healthy 42-year-old man that was initially presumed to be an atypical meningioma. The findings based on conventional and advanced magnetic resonance sequences, including diffusion-weighted imaging, perfusion weighted imaging and proton magnetic resonance spectroscopy, as well as histopathological aspects, are discussed.

7.
BJR Case Rep ; 5(1): 20180037, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31131120

RESUMEN

We present a case of a 30-year-old man who had a 3-year history of low back pain. MRI demonstrated an infiltrative mass, affecting the vertebral body and pedicles of L4, with some extension to the vertebral canal. There was also tumor invasion in the inferior vena cava and in the left iliopsoas muscle. The anatomopathological examination of the resected L4 vertebral body was of a malignant neoplasia compatible with mesenchymal chondrosarcoma (high histological grade). About 2 months after surgery, he developed a progressive bladder incontinence, bilateral leg weakness and severe back pain. A new MRI was obtained, confirming progression of the disease. An occipital scalp lesion was detected and biopsy confirmed cutaneous metastasis. Primary malignant bone tumors are rare but should be ruled out in young patients with persistent low back pain. We present a case of a confirmed mesenchymal chondrosarcoma affecting lumbar spine, with MRI and pathological illustrations. Early diagnosis may improve the chances of local disease control and even cure.

8.
Breast J ; 14(1): 68-75, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18086274

RESUMEN

Papillary neoplasms of the breast represent a complex spectrum ranging from benign to malignant lesions. The myoepithelial cell (MEC) layer is generally continuous in papillomas and increasingly discontinuous to absent in atypical and malignant counterparts. Identification of MECs can be difficult on morphological grounds and currently relies on immunomarkers. We investigated the potential role of p63 and CD10 in 20 papillary lesions and compared them with 1A4 and calponin. In 18 cases, adjacent normal breast tissue was available for study. All four markers were diffusely positive in all samples of normal tissue and benign papillomas indicating similar sensitivity in the identification of MECs. Intense positivity was found in 100% of the cases with 1A4 and CD10, but in only 76% with calponin and in 60.5% with p63 (differences statistically significant, p < 0.05), suggesting that the former two render more reproducible results. The most specific markers were p63 and CD10 which showed cross-reactivity in 0% and in up to 33% of the cases respectively. 1A4 and calponin showed diffuse cross-reactivity in all cases. When assessing benign versus atypical papillomas, the best parameters were diffuse positivity using CD10 or p63, and continuous MEC layer, mainly using CD10. When comparing benign papillomas to carcinomas all parameters were equally useful with 1A4 and CD10. Regardless of the marker, intense positivity was the only parameter that could distinguish atypical papillomas from papillary carcinomas. p63 staining, which renders a nuclear and mostly discontinuous reactivity, was not as useful as the other markers when the parameter continuous MEC layer was evaluated. Although CD10 seems to combine the highest specificity and reproducibility with a good sensitivity, reproducibility of 1A4 is higher. Thus, a minimum panel to assess papillary lesions should include both markers. Although p63 is the most specific, its nuclear and discontinuous pattern may lead to erroneous diagnosis, especially in the differentiation between benign papillomas and atypical/malignant lesions.


Asunto(s)
Biomarcadores de Tumor/análisis , Neoplasias de la Mama/patología , Carcinoma Papilar/patología , Proteínas de la Membrana/análisis , Neprilisina/análisis , Neoplasias de la Mama/química , Neoplasias de la Mama/metabolismo , Proteínas de Unión al Calcio/análisis , Carcinoma Papilar/química , Carcinoma Papilar/metabolismo , Diagnóstico Diferencial , Femenino , Humanos , Proteínas de Microfilamentos/análisis , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Calponinas
10.
J Craniovertebr Junction Spine ; 8(4): 387-389, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29403257

RESUMEN

The spinal form of idiopathic hypertrophic pachymeningitis (IHP) is a rare condition characterized by a chronic progressive diffuse inflammatory fibrosis of the dura mater, which may evolve to the compression of the spinal cord. We present a case report about IHP focusing on its features in magnetic resonance imaging, which are determined by an intradural extramedullary mass in the cervical spine showing hypointensity on T2-weighted images and peripheral enhancement, causing compression of the spinal cord. Histological analysis showed a nonspecific chronic inflammatory process in dense fibrous tissue. The patient had a good outcome after therapy with steroids.

11.
Appl Immunohistochem Mol Morphol ; 14(1): 71-7, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16540734

RESUMEN

The immunohistochemical detection of myoepithelial cells in benign sclerosing lesions of the breast is useful in distinguishing them from tubular carcinoma. So far, this detection has been carried out using antibodies against cytoskeletal proteins, such as alpha-smooth muscle actin (1A4) and calponin. However, the specificity of these markers has been questioned since they may be expressed in stromal myofibroblasts and vascular smooth muscle. Recently, two novel myoepithelial markers have been described: the nuclear protein p63, a member of the p53 family, and the surface antigen CD10, also known as common acute lymphoblastic leukemia antigen (CALLA). The authors assessed the use of p63 and CD10 in the differential diagnosis between benign sclerosing lesions, such as sclerosing adenosis and radial scar, and tubular carcinoma, in comparison to the traditional myoepithelial markers 1A4 and calponin. p63, CD10, 1A4, and calponin were expressed in myoepithelial cells of all benign lesions and were consistently negative in all cases of tubular carcinoma. In contrast to cytoskeletal proteins, p63 and CD10 were mostly confined to myoepithelial cells and thus were more specific than the traditional counterparts. However, 1A4 was more intensely expressed and more reproducible than the novel markers. In conclusion, p63 and CD10 may be used as a complement to 1A4 in distinguishing benign sclerosing lesions from tubular carcinoma of the breast.


Asunto(s)
Adenocarcinoma/diagnóstico , Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/diagnóstico , Neprilisina/biosíntesis , Fosfoproteínas/biosíntesis , Transactivadores/biosíntesis , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Biomarcadores de Tumor/análisis , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Proteínas de Unión al ADN , Diagnóstico Diferencial , Femenino , Genes Supresores de Tumor , Humanos , Inmunohistoquímica , Neprilisina/análisis , Fosfoproteínas/análisis , Esclerosis , Transactivadores/análisis , Factores de Transcripción , Proteínas Supresoras de Tumor
12.
Arch Neurol ; 62(6): 1008-10, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15956175

RESUMEN

BACKGROUND: Schistosoma mansoni is a parasitic trematoid worm that infects humans. Schistosomiasis is endemic in parts of South America, sub-Saharan Africa, the Middle East, and some Caribbean islands. Disorders of the liver and gastrointestinal tract are the most common clinical manifestations. The central nervous system is not usually affected. The most common neurologic manifestation is transverse myelitis. In some circumstances, the eggs of S. mansoni are found in the brain, causing inflammatory reaction. OBJECTIVE: To describe a young Brazilian patient with partial epileptic seizures caused by a granulomatous lesion due to S. mansoni. CONCLUSION: In endemic areas or in patients with a positive epidemiological history, schistosomiasis must be considered as a possible diagnosis of seizures, particularly when they are associated with granulomatous lesions on magnetic resonance imaging.


Asunto(s)
Corteza Cerebral/fisiopatología , Corteza Cerebral/parasitología , Neuroesquistosomiasis/diagnóstico , Neuroesquistosomiasis/fisiopatología , Convulsiones/diagnóstico , Convulsiones/parasitología , Adulto , Humanos , Masculino
13.
Brain Res Dev Brain Res ; 154(2): 217-25, 2005 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-15707675

RESUMEN

Oxidative stress has been implicated in motoneuron death secondary to axotomy in the neonatal period. We studied the effect of sciatic transection at P2 on the motoneuron population in the lumbar enlargement of newborn rats looking for a protective role of daily doses of the antioxidant melatonin. The animals were allowed to survive from P2 to P7, and the spinal cords were processed for immunohistochemistry for superoxide dismutase (SOD) isoforms 1 and 2 and nitric oxide synthase (nNOS) (at 2, 3, 5, and 7 days post-natum), histological neuron counting and immunoblotting for the SOD isoforms (both at 2, 3, and 7 days post-natum). Melatonin reduced by 75% motoneuron loss due to axotomy at P3 and P7. Neither sciatic transection nor melatonin induced any detectable changes in the immunoreactivity patterns of the enzymes. SOD1 was expressed diffusely in the cytoplasm of neurons and ependyma and in the nuclei of presumed glial cells from P2 to P7. SOD2 was detected in neurons and ependyma and its expression was similar to SOD1 at P2 but decreased later to a spotty cytoplasmic pattern in motoneurons. nNOS was localized to the cytoplasm of a few small cells in the ventral and dorsal horns and around the central canal. Immunoblotting at 1 day postaxotomy detected a significant increase in SOD1 expression in melatonin-treated axotomized rats and a decrease in controls after axotomy and vehicle. Blotting for SOD2 did not show significant changes between groups at any time. This study provides the first evidence that SOD2 immunostaining pattern varies during motoneuron postnatal development and that melatonin alters the expression of SOD1 in the present model of peripheral nerve injury.


Asunto(s)
Melatonina/uso terapéutico , Neuronas Motoras/efectos de los fármacos , Neuropatía Ciática/tratamiento farmacológico , Médula Espinal/citología , Superóxido Dismutasa/metabolismo , Factores de Edad , Animales , Animales Recién Nacidos , Antioxidantes/uso terapéutico , Western Blotting/métodos , Recuento de Células/métodos , Inmunohistoquímica/métodos , Región Lumbosacra , Neuronas Motoras/enzimología , Proteínas del Tejido Nervioso/metabolismo , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo I , Ratas , Neuropatía Ciática/cirugía , Médula Espinal/efectos de los fármacos , Médula Espinal/enzimología , Superóxido Dismutasa-1 , Factores de Tiempo
15.
PLoS One ; 10(3): e0116831, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25757086

RESUMEN

Diagnostic imaging techniques play an important role in assessing the exact location, cause, and extent of a nerve lesion, thus allowing clinicians to diagnose and manage more effectively a variety of pathological conditions, such as entrapment syndromes, traumatic injuries, and space-occupying lesions. Ultrasound and nuclear magnetic resonance imaging are becoming useful methods for this purpose, but they still lack spatial resolution. In this regard, recent phase contrast x-ray imaging experiments of peripheral nerve allowed the visualization of each nerve fiber surrounded by its myelin sheath as clearly as optical microscopy. In the present study, we attempted to produce high-resolution x-ray phase contrast images of a human sciatic nerve by using synchrotron radiation propagation-based imaging. The images showed high contrast and high spatial resolution, allowing clear identification of each fascicle structure and surrounding connective tissue. The outstanding result is the detection of such structures by phase contrast x-ray tomography of a thick human sciatic nerve section. This may further enable the identification of diverse pathological patterns, such as Wallerian degeneration, hypertrophic neuropathy, inflammatory infiltration, leprosy neuropathy and amyloid deposits. To the best of our knowledge, this is the first successful phase contrast x-ray imaging experiment of a human peripheral nerve sample. Our long-term goal is to develop peripheral nerve imaging methods that could supersede biopsy procedures.


Asunto(s)
Procesamiento de Imagen Asistido por Computador/instrumentación , Nervio Ciático/diagnóstico por imagen , Tomografía por Rayos X/métodos , Humanos , Nervio Ciático/patología , Sincrotrones , Tomografía por Rayos X/instrumentación
16.
Brain Res ; 926(1-2): 33-41, 2002 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-11814404

RESUMEN

The neuronal isoform of nitric oxide synthase (nNOS), a NADPH-dependent diaphorase, is considered to play a role in motoneuron death induced by sciatic nerve transection in neonatal rats. Neuronal loss in these circumstances has been correlated with nitric oxide (NO) production and NADPH-diaphorase positivity in motoneurons after axotomy. In the present study we looked for a possible protective effect of melatonin, an antioxidant agent and inhibitor of nNOS, on spinal motoneurons after axonal injury. Neonatal Wistar rats (P2) were submitted to sciatic nerve transection and allowed to survive to P7. Melatonin at doses of 1, 5, 10, 50 and 100 mg/kg was given subcutaneously before and at intervals after the surgery. Controls operated in the same way received dilution vehicle or no treatment. The animals were killed by perfusion of fixative and the spinal cord was examined in serial paraffin sections. The motoneurons of the sciatic pool were counted in the axotomized and contralateral sides. Immunohistochemistry for nNOS and glial fibrillary acidic protein was used to evaluate nNOS expression in the axotomized cells and the astrocytic response. We found that melatonin at doses of 1-50 mg/kg decreased neuronal death. Astrocytic hypertrophy in melatonin treated animals was less intense. There were no differences in nNOS expression between treated and control rats, and surviving motoneurons of the sciatic pool did not express the enzyme, suggesting that nNOS may not be involved in neuronal death or survival in these experimental conditions. Possible mechanisms of melatonin neuroprotection, which was equally effective at doses of 1-50 mg/kg, are discussed. Doses of 50 and 100 mg/kg caused failure to thrive, seizures or death. The fact that neuroprotective doses were far smaller than toxic ones should encourage testing of melatonin in neurologic diseases.


Asunto(s)
Antioxidantes/farmacología , Melatonina/farmacología , Neuronas Motoras/citología , Fármacos Neuroprotectores/farmacología , Nervio Ciático/patología , Animales , Animales Recién Nacidos , Astrocitos/química , Axotomía , Relación Dosis-Respuesta a Droga , Proteína Ácida Fibrilar de la Glía/análisis , Inmunohistoquímica , Neuronas Motoras/efectos de los fármacos , Neuronas Motoras/enzimología , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo I , Ratas , Ratas Wistar , Nervio Ciático/fisiología
17.
Toxicon ; 40(10): 1483-6, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12368118

RESUMEN

Myonecrosis is one of the most common effects of Bothrops jararacussu venom, but little is known about the action of this venom on other tissues. In this study, we used transmission electron microscopy to examine the influence of B. jararacussu venom on nerve tissue. A sublethal dose of venom (80 microg) was injected into the tibialis anterior muscle of mice which were then killed at various intervals up to 6 h after venom injection. The venom caused massive, progressive axonal damage beginning 2 min after inoculation and after 6 h, all intramuscular nerve bundles were completely depleted of nerve fibers. The most striking finding was myelin breakdown. The ultrastructural changes observed and the time course of the nerve lesions indicated that B. jararacussu venom acted directly on nerve tissue, possibly on the phospholipids of the myelin sheath. The axonal damage reported here may be of relevance to explain, at least in part, the muscular atrophy and poor recovery in muscle function seen in human and experimental envenomations.


Asunto(s)
Bothrops , Venenos de Crotálidos/toxicidad , Enfermedades Desmielinizantes/inducido químicamente , Degeneración Nerviosa/inducido químicamente , Nervios Periféricos/efectos de los fármacos , Animales , Enfermedades Desmielinizantes/patología , Masculino , Ratones , Microscopía Electrónica , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/ultraestructura , Degeneración Nerviosa/patología , Nervios Periféricos/ultraestructura , Terminales Presinápticos/efectos de los fármacos , Terminales Presinápticos/ultraestructura
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