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Search Results: 1 - 10 of 208487 matches for " Chimelli L. "
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A Morphological Approach to the Diagnosis of Protozoal Infections of the Central Nervous System
Leila Chimelli
Pathology Research International , 2011, DOI: 10.4061/2011/290853
Abstract: Protozoal infections, though endemic to certain regions, can be seen all around the world, because of the increase in travel and migration. In addition, immunosuppression associated with various conditions, particularly with HIV infection, favors the occurrence of more severe manifestations and failure to respond to treatments. The CNS may be the only affected system; when not, it is often the most severely affected. Despite information obtained from clinical, laboratory, and imaging procedures that help to narrow the differential diagnosis of intracranial infections, there are cases that need confirmation with biopsy or autopsy. Predominant presentations are meningoencephalitis (trypanosomiasis), encephalopathy (cerebral malaria), or as single or multiple pseudotumoral enhancing lesions (toxoplasmosis, reactivated Chagas' disease). The immune reconstitution disease, resulting from enhancement of pathogen-specific immune responses after HAART, has altered the typical presentation of toxoplasmosis and microsporidiosis. In this paper, a morphological approach for the diagnosis of protozoal infections affecting the CNS (amoebiasis, cerebral malaria, toxoplasmosis, trypanosomiasis, and microsporidiosis) is presented. 1. Introduction Protozoa are single-cell organisms widely distributed in nature. Protozoal infections, though endemic to certain regions for reasons of climate and availability of intermediate hosts to transmit them to man, are also seen outside their original geographical areas, probably facilitated by the increase in international travel and migration of people from their native countries [1–3]. These infectious diseases should be largely known, particularly because immunosuppression associated with HIV infection, solid organ, or bone marrow transplant with long-term immunosuppression caused by medications, favor the occurrence of more severe clinical manifestations and failure to respond to specific treatments. A significant proportion of these cases have been described due to immigrants coming from tropical countries to nontropical countries, and increased awareness of these diseases is needed among health professionals dealing with such patients [1, 4, 5]. For a number of these organisms, the nervous system is only one of the many systems involved; however, this localization may often be the most severe and incompatible with the survival of the patient [2, 6]. Although much information is obtained from clinical examination, laboratory, and imaging procedures [7, 8], all playing a crucial role in identifying and narrowing the differential
Neuropatias periféricas na infancia: uma abordagem neuropatológica
Chimelli, Leila;
Arquivos de Neuro-Psiquiatria , 1996, DOI: 10.1590/S0004-282X1996000300025
Abstract: peripheral neuropathies affect children more often than the young and middle age adults, but less frequently than the elderly. they differ from those in the adults because of the high incidence of hereditary neuropathies, including those associated with metabolic and degenerative disorders of the central nervous system; the low incidence of toxic neuropathies and those associated with systemic disorders; and a lower incidence of chronic acquired polineuropathies. nerve biopsies are indicated if the diagnosis has not been made with clinical and electrophysiologic studies and other methods, and should only be performed in laboratories with appropriate techniques for the study of the nerve. it is important to know the normal development of the nerve, the thickness of the myelin sheath and the distribution of small and large fibers, according to the age. the main morphological aspects of the most frequent neuropathies in children - acquired (inflammatory, demyelinating) and hereditary (sensory-motor, sensory-autonomic, ataxic, and those associated with metabolic and degenerative disorders), are reviewed.
Effects of chronic heart disease on skeletal muscle fiber size
Mattiello-Sverzut, A.C.;Chimelli, L.;Teixeira, S.;Pierre, M.;Oliveira, L.;
Brazilian Journal of Medical and Biological Research , 2005, DOI: 10.1590/S0100-879X2005000200019
Abstract: size changes in muscle fibers of subjects with chronic heart disease (chd) have been reported, although a consensus has not been achieved. the aims of the present study were to investigate a possible association between chd and fiber size changes in the brachial biceps compared to subjects without heart disease. forty-six muscle samples were obtained in autopsies of individuals (13 to 84 years) without neuromuscular disorders, 19 (10 males and 9 females) with, and 27 (14 males and 13 females) without chd. in all cases muscle sections were stained with hematoxylin and eosin and processed for the visualization of myofibrillar atpase activity. the lesser diameter of type 1 and type 2 fibers was obtained tracing their outlines (at least 150 fibers of each type per sample) onto an image analyzer connected to a computer. the results were analyzed statistically comparing males and females with and without chd. type 1 fiber mean lesser diameters were 51.51 and 54.52 μm in males (normal range 34-71 μm) and 45.65 and 55.42 μm in females (normal range 34-65 μm) without and with chd, respectively; type 2 fibers measured 54.31, 58.23, 41.15, and 49.57 μm, respectively (normal range 36-79 μm for males and 32-59 μm for females). no significant difference in fiber size was detected in 24 males with and without chd, while in 22 females there was a significant increase in size in those with cardiomyopathy. we concluded that chd does not determine significant changes in fiber size. however, in females, there is some hypertrophy which, despite within normal range, may reflect morphologic heterogeneity of the sample, or the daily life activities in the upper limbs as a compensatory mechanism to fatigability that affect predominantly the lower limbs in subjects with chd.
Quantitative evidence for neurofilament heavy subunit aggregation in motor neurons of spinal cords of patients with amyotrophic lateral sclerosis
Mendon?a, D.M.F.;Chimelli, L.;Martinez, A.M.B.;
Brazilian Journal of Medical and Biological Research , 2005, DOI: 10.1590/S0100-879X2005000600015
Abstract: amyotrophic lateral sclerosis (als), a neurodegenerative disease of unknown etiology, affects motor neurons leading to atrophy of skeletal muscles, paralysis and death. there is evidence for the accumulation of neurofilaments (nf) in motor neurons of the spinal cord in als cases. nf are major structural elements of the neuronal cytoskeleton. they play an important role in cell architecture and differentiation and in the determination and maintenance of fiber caliber. they are composed of three different polypeptides: light (nf-l), medium (nf-m) and heavy (nf-h) subunits. in the present study, we performed a morphological and quantitative immunohistochemical analysis to evaluate the accumulation of nf and the presence of each subunit in control and als cases. spinal cords from patients without neurological disease and from als patients were obtained at autopsy. in all als cases there was a marked loss of motor neurons, besides atrophic neurons and preserved neurons with cytoplasmic inclusions, and extensive gliosis. in control cases, the immunoreaction in the cytoplasm of neurons was weak for phosphorylated nf-h, strong for nf-m and weak for nf-l. in als cases, anterior horn neurons showed intense immunoreactivity in focal regions of neuronal perikarya for all subunits, although the difference in the integrated optical density was statistically significant only for nf-h. furthermore, we also observed dilated axons (spheroids), which were immunopositive for nf-h but negative for nf-m and nf-l. in conclusion, we present qualitative and quantitative evidence of nf-h subunit accumulation in neuronal perikarya and spheroids, which suggests a possible role of this subunit in the pathogenesis of als.
Quantitative evidence for neurofilament heavy subunit aggregation in motor neurons of spinal cords of patients with amyotrophic lateral sclerosis
Mendon?a D.M.F.,Chimelli L.,Martinez A.M.B.
Brazilian Journal of Medical and Biological Research , 2005,
Abstract: Amyotrophic lateral sclerosis (ALS), a neurodegenerative disease of unknown etiology, affects motor neurons leading to atrophy of skeletal muscles, paralysis and death. There is evidence for the accumulation of neurofilaments (NF) in motor neurons of the spinal cord in ALS cases. NF are major structural elements of the neuronal cytoskeleton. They play an important role in cell architecture and differentiation and in the determination and maintenance of fiber caliber. They are composed of three different polypeptides: light (NF-L), medium (NF-M) and heavy (NF-H) subunits. In the present study, we performed a morphological and quantitative immunohistochemical analysis to evaluate the accumulation of NF and the presence of each subunit in control and ALS cases. Spinal cords from patients without neurological disease and from ALS patients were obtained at autopsy. In all ALS cases there was a marked loss of motor neurons, besides atrophic neurons and preserved neurons with cytoplasmic inclusions, and extensive gliosis. In control cases, the immunoreaction in the cytoplasm of neurons was weak for phosphorylated NF-H, strong for NF-M and weak for NF-L. In ALS cases, anterior horn neurons showed intense immunoreactivity in focal regions of neuronal perikarya for all subunits, although the difference in the integrated optical density was statistically significant only for NF-H. Furthermore, we also observed dilated axons (spheroids), which were immunopositive for NF-H but negative for NF-M and NF-L. In conclusion, we present qualitative and quantitative evidence of NF-H subunit accumulation in neuronal perikarya and spheroids, which suggests a possible role of this subunit in the pathogenesis of ALS.
Modulation of fibronectin expression in the central nervous system of Lewis rats with experimental autoimmune encephalomyelitis
De-Carvalho, M.C.A.;Chimelli, L.M.C.;Quirico-Santos, T.;
Brazilian Journal of Medical and Biological Research , 1999, DOI: 10.1590/S0100-879X1999000500012
Abstract: fibronectin (fn), a large family of plasma and extracellular matrix (ecm) glycoproteins, plays an important role in leukocyte migration. in normal central nervous system (cns), a fine and delicate mesh of fn is virtually restricted to the basal membrane of cerebral blood vessels and to the glial limitans externa. experimental autoimmune encephalomyelitis (eae), an inflammatory cns demyelinating disease, was induced in lewis rats with a spinal cord homogenate. during the preclinical phase and the onset of the disease, marked immunolabelling was observed on the endothelial luminal surface and basal lamina of spinal cord and brainstem microvasculature. in the paralytic phase, a discrete labelling was evident in blood vessels of spinal cord and brainstem associated or not with an inflammatory infiltrate. conversely, intense immunolabelling was present in cerebral and cerebellar blood vessels, which were still free from inflammatory cuffs. shortly after clinical recovery minimal labelling was observed in a few blood vessels. brainstem and spinal cord returned to normal, but numerous inflammatory foci and demyelination were still evident near the ventricle walls, in the cerebral cortex and in the cerebellum. intense expression of fn in brain vessels ascending from the spinal cord towards the encephalon preceded the appearance of inflammatory cells but faded away after the establishment of the inflammatory cuff. these results indicate an important role for fn in the pathogenesis of cns inflammatory demyelinating events occurring during eae.
Modulation of fibronectin expression in the central nervous system of Lewis rats with experimental autoimmune encephalomyelitis
De-Carvalho M.C.A.,Chimelli L.M.C.,Quirico-Santos T.
Brazilian Journal of Medical and Biological Research , 1999,
Abstract: Fibronectin (FN), a large family of plasma and extracellular matrix (ECM) glycoproteins, plays an important role in leukocyte migration. In normal central nervous system (CNS), a fine and delicate mesh of FN is virtually restricted to the basal membrane of cerebral blood vessels and to the glial limitans externa. Experimental autoimmune encephalomyelitis (EAE), an inflammatory CNS demyelinating disease, was induced in Lewis rats with a spinal cord homogenate. During the preclinical phase and the onset of the disease, marked immunolabelling was observed on the endothelial luminal surface and basal lamina of spinal cord and brainstem microvasculature. In the paralytic phase, a discrete labelling was evident in blood vessels of spinal cord and brainstem associated or not with an inflammatory infiltrate. Conversely, intense immunolabelling was present in cerebral and cerebellar blood vessels, which were still free from inflammatory cuffs. Shortly after clinical recovery minimal labelling was observed in a few blood vessels. Brainstem and spinal cord returned to normal, but numerous inflammatory foci and demyelination were still evident near the ventricle walls, in the cerebral cortex and in the cerebellum. Intense expression of FN in brain vessels ascending from the spinal cord towards the encephalon preceded the appearance of inflammatory cells but faded away after the establishment of the inflammatory cuff. These results indicate an important role for FN in the pathogenesis of CNS inflammatory demyelinating events occurring during EAE.
Componente oligodendroglial e neuronal em glioblastomas: possível rela??o com o prognóstico
Pinto, Luciana Wernersbach;Chimelli, Leila;
Arquivos de Neuro-Psiquiatria , 2004, DOI: 10.1590/S0004-282X2004000600026
Abstract: glioblastomas are high grade astrocytic tumors and current histology criteria does not explain the longer survival in some cases. presence of oligodendroglial component has been suggested as possible marker for better outcome by the international who working group of experts and by the proponents of the sainte-anne hospital classification (2000). the latter also states that a neuronal component is associated with better survival. the aim of this study was to analyze a series of 40 patients with tumors classified as glioblastomas based on the who criteria, in order to identify: the presence of an oligodendroglial component, using morphologic criteria; the presence of a neuronal component, using immunohistochemical markers (antibodies anti-neurofilament and synaptofisin). the histological and immunohistochemical findings were correlated with patients' survival and other variables of possible prognostic significance were also studied. oligodendroglial component was identified in 11 cases and neuronal component in 7. despite the small number of patients studied, this review detected a longer survival in patients with oligodendroglial component. the significance of expression of neuronal markers in malignant gliomas is still to be confirmed, with the evaluation of larger series.
Diffusion-weighted MR images and pineoblastoma: diagnosis and follow-up
Gasparetto, Emerson L.;Cruz Jr, L. Celso Hygino da;Doring, Thomas M.;Araújo, Bertha;Dantas, Mário Alberto;Chimelli, Leila;Domingues, Romeu C.;
Arquivos de Neuro-Psiquiatria , 2008, DOI: 10.1590/S0004-282X2008000100015
Abstract: pineoblastomas are uncommon pineal tumors, which demonstrate rapid growing and poor prognosis. we report the case of a 43-year-old man with an enhancing pineal region mass, which showed restriction of the diffusion on diffusion-weighted (dw) mr images. the surgical biopsy defined the diagnosis of pineoblastoma and the therapy was initiated with radiation and chemotherapy. three months later, the follow-up mr imaging showed areas suggestive of necrosis and the dw images demonstrate no significant areas of restricted diffusion. the differential diagnosis of pineal region masses that could show restriction of diffusion is discussed.
Valor do esfrega?o no diagnóstico per-operatório dos tumores provenientes de neurocirurgias
Chimelli, Leila;Campos, Ivelise de Souza;
Arquivos de Neuro-Psiquiatria , 1993, DOI: 10.1590/S0004-282X1993000200007
Abstract: the smear technique has been used for rapid diagnosis of tumors removed in neurosurgeries in many neuropathological centers. in order to> assess the diagnostic accuracy of this technique, we examined 137 smears and made a cytohistological correlation. our cases include 12 astrocytomas, 4 anaplastic astrocytomas, 26 glioblastomas, 7 oligodendrogliomas, 5 medulloblastomas, 8 schwannomas, 17 meningiomas, 13 pituitary adenomas, 20 metastatic tumors and 18 assorted tumors and non neoplastic lesions. the correct diagnosis was made in 91.2% of the cases which coincides to the literature. the knowledge of the localization and the characteristic morphologic features of some tumors were important for the diagnosis. the ability to recognize normal nervous tissue in smears was important even to help the surgeon to reach the tumor. we believe that the use of smears should be encouraged in our country in view of the simplicity of its preparation and accuracy of results.
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