Altered mRNA expression for brain-derived neurotrophic factor and type II calcium/calmodulin-dependent protein kinase in the hippocampus of patients with intractable temporal lobe epilepsy.

The expression of brain-derived neurotrophic factor and the alpha subunit of calcium/calmodulin-dependent protein kinase II mRNA in hippocampi obtained during surgical resections for intractable temporal lobe epilepsy were examined. Both calcium/calmodulin-dependent protein kinase II and brain-derived neurotrophic factor are localized heavily within the hippocampus and have been implicated in regulating hippocampal activity (Kang and Schuman [1995] Science 267:1658-1662; Suzuki [1994] Intl J Biochem 26:735-744). Also, the autocrine and paracrine actions of brain-derived neurotrophic factor within the central nervous system make it a likely candidate for mediating morphologic changes typically seen in the epileptic hippocampus. Quantitative assessments of mRNA levels in epileptic hippocampi relative to autopsy controls were made by using normalized densitometric analysis of in situ hybridization. In addition, correlations between clinical data and mRNA levels were studied. Relative to autopsy control tissue, decreased hybridization to mRNA of the alpha subunit of calcium/calmodulin-dependent protein kinase II and increased hybridization to brain-derived neurotrophic factor mRNA were found throughout the granule cells of the epileptic hippocampus. There also was a significant negative correlation between the duration of epilepsy and the expression of mRNA for brain-derived neurotrophic factor. These results are similar qualitatively to those found in animal models of epilepsy and suggest that chronic seizure activity in humans leads to persistent alterations in gene expression. Furthermore, these alterations in gene expression may play a role in the etiology of the epileptic condition.

Developmental patterns of BCL-2 and BCL-X polypeptide expression in the human spinal cord.

The cell death suppressors bcl-2 and bcl-x are developmentally regulated and may modulate physiologic cell death in the central nervous system (CNS). However, little data are currently available on the expression patterns of these polypeptides in the human CNS. We examined the ontogeny of bcl-2 and bcl-x in 12 human spinal cords of gestational ages (GA) between 5 and 39 weeks and in 3 adult cords. Paraffin sections were probed by immunohistochemistry using well-characterized, commercially available antibodies that had been raised against poorly conserved epitopes of these homologous proteins. Between 5 and 10 weeks GA, bcl-2 immunoreactivity was identified in primitive neuroepithelial cells of the ventricular zone. Individual cells of the mantle zone were stained including clusters of early anterior horn cells. Bcl-x immunoreactivity was most prominent in differentiating neurons of the mantle zone and less pronounced in the ventricular zone. Between 10 and 14 weeks GA, bcl-2 staining was observed in cells lining the central canal, neurons of the dorsal horn (especially laminae I and II), and in anterior horn cells. The latter exhibited a range of staining intensities from moderate to nondetectable. Bcl-2 immunoreactivity became markedly reduced between 15 and 25 weeks GA, persisting only in ependymal cells. In contrast, strong bcl-x staining was observed in most neurons throughout development and into adulthood. The period of apparent bcl-2 down-regulation overlaps with a peak in physiologic motoneuron death and the establishment of functional neuromuscular synapses in the human spinal cord. These findings suggest that bcl-2 and bcl-x may both be required for survival of early postmitotic neurons before appropriate synaptic connections have been established. Continued neuronal survival (after bcl-2 is down-regulated) may require persistent bcl-x expression in addition to target-derived neurotrophic factors made available through the formation of appropriate synapses.

MAP2 expression in the developing human fetal spinal cord and following xenotransplantation.

Human fetal spinal cord (FSC) tissue was obtained from elective abortions at 6-14 wk gestational age (GA). The specimens were then either immediately processed for immunohistochemical analysis or xenotransplantation. In the latter case, donor tissue was prepared as a dissociated cell suspension and then introduced either subpially or intraspinally into contusion lesions of the adult rat midthoracic spinal cord. The xenografts were subsequently examined by conventional histological and immunohistochemical methods at 2-3 mo postgrafting. Immunostaining showed that MAP2 was expressed heavily in cells residing in the mantle layer of the human fetal spinal cord in situ as early as 6 wk GA. Subpial and intraparenchymal xenografts also were intensely immunoreactive for MAP2, but no staining of surrounding host neural tissue was detected. We conclude that the differential expression of MAP2 can be used to distinguish human graft tissue from the surrounding rat spinal cord in this xenograft paradigm. Under appropriate staining conditions, MAP2 can thus serve to facilitate analyses of host-graft integration, donor cell migration, and neuritic outgrowth.

Distinct neurodevelopmental patterns of bcl-2 and bcl-x expression are altered in glioneuronal hamartias of the human temporal lobe.

Bcl-2 and bcl-xL are homologous proteins that inhibit cell death and are expressed in the nervous system. We tested the hypothesis that aberrant expression of such "death suppressor" molecules may promote the survival of abnormal cells in glioneuronal lesions associated with temporal lobe epilepsy. The normal pattern of bcl-2 and bcl-x expression was studied in postmortem human fetal and adult temporal lobes. Formalin-fixed, paraffin-embedded tissue sections were probed for bcl-2 and bcl-x in immunohistochemical studies using well-characterized primary antibodies that had been raised against epitopes that are not shared by these proteins. Strong staining for both proteins was observed in the ventricular zone and in migrating, postmitotic and postmigratory young neurons of the neocortex, hippocampus, and entorhinal cortex from 6 to 20 weeks gestational age (GA). However, bcl-2 immunoreactivity gradually decreased to weak or nondetectable levels between 20 and 39 weeks GA, while strong bcl-x staining of neurons persisted throughout fetal development and into adulthood. Twenty-eight temporal lobe resections from children and adults ranging in age from 1 to 45 years (mean=19 years) with intractable epilepsy were then screened for differences in the pattern of bcl-2 and bcl-x expression compared to normal controls. Bcl-2 (but not bcl-x) was strongly immunoreactive in small, immature-appearing cells that were components of microscopic glioneuronal aggregates (hamartias) and that have been shown previously to express an embryonic form of the neural cell adhesion molecule. These immature cells were immunonegative for standard markers of neuronal and glial lineage and were negative for Ki67, suggesting that they are post-mitotic. The persistent expression of bcl-2 and apparent downregulation of bcl-x in these cells represent deviations from the normal ontogeny of these molecules in the human nervous system. These data suggest that dysregulation of bcl-2 and related proteins may be involved in the pathogenesis of some temporal lobe malformative lesions.

Characteristics of human fetal spinal cord grafts in the adult rat spinal cord: influences of lesion and grafting conditions.

The present study evaluated the growth potential and differentiation of human fetal spinal cord (FSC) tissue in the injured adult rat spinal cord under different lesion and grafting conditions. Donor tissue at 6-9 weeks of gestational age was obtained through elective abortions and transplanted either immediately into acute resection (solid grafts) or into chronic contusion (suspension and solid grafts) lesions (i.e., 14-40 days after injury) in the thoracic spinal cord. The xenografts were then examined either histologically in plastic sections or immunocytochemically 1-3 months postgrafting. Intraspinal grafts in acute lesions demonstrated an 83% survival rate and developed as well-circumscribed nodules that were predominantly composed of immature astrocytes. Solid-piece grafts in chronic contusion lesions exhibited a 92% survival rate and also developed as nodular masses. These grafts, however, contained many immature neurons 2 months postgrafting. Suspension grafts in chronic contusion lesions had an 85% survival rate and expanded in a nonrestrictive, diffuse pattern. These transplants demonstrated large neuronally rich areas of neural parenchyma. Extensive neuritic outgrowth could also be seen extending from these grafts into the surrounding host spinal cord. These findings show that human FSC tissue reliably survives and differentiates in both acute and chronic lesions. However, both the lesion environment and the grafting techniques can greatly influence the pattern of differentiation and degree of host-graft integration achieved.

Disseminated microsporidiosis especially infecting the brain, heart, and kidneys. Report of a newly recognized pansporoblastic species in two symptomatic AIDS patients.

Microsporidia have emerged as important opportunistic AIDS pathogens of the alimentary, respiratory, and urinary tracts. Although nonhuman mammalian microsporidia infections typically include encephalitis, CNS microsporidiosis has not been reported in patients with AIDS. A 33-year-old white male and an 8-year-old black girl presented with seizures and declining mental status. Central nervous system (CNS) imaging studies revealed small peripherally and diffusely enhancing lesions present for at least 2 and 4 months before death, respectively. Both patients expired despite empirical anti-toxoplasma therapy. Their brains contained innumerable soft gray matter lesions that consisted of central areas of necrosis, filled with free spores and spore-laden macrophages, surrounded by microsporidia-infected astrocytes. The complete autopsy of the child also revealed necrotizing and sclerosing cardiac and renal microsporidiosis and infection of the pancreas, thyroid, parathyroids, liver, spleen, lymph nodes, and bone marrow. Infected cells included astrocytes, cardiac myocytes, epithelium, endothelium, vascular smooth muscle cells, hepatocytes, adipocytes, Schwann cells, and macrophages. Light and electron microscopic studies revealed pansporoblastic development within thick-walled sporophorous vacuoles of parasite origin. Although most similar to Pleistophora sp and Thelohania sp, this microsporidian is different from any known species. Microsporidiosis should be considered as the possible cause of a wide range of diseases in AIDS patients, including CNS, cardiac, and renal.

Rapidly progressive dementia: a clinicopathologic correlation.

We evaluated a 66-year-old man with a rapidly progressive, akinetic-rigid dementia syndrome. Despite extensive testing, which included magnetic resonance imaging (MRI), we were unable to make the correct antemortem diagnosis. Autopsy demonstrated spontaneous progressive multifocal leukoencephalopathy. This report illustrates that even in the absence of characteristic MRI findings, this uncommon cause of dementia should be considered in the differential diagnosis of rapidly progressive, akinetic-rigid syndromes with dementia.

Divergent differentiation in pleomorphic xanthoastrocytoma. Evidence for a neuronal element and possible relationship to ganglion cell tumors.

We report the detection of cytoplasmic immunoreactivity for neuronal/neuroendocrine antigens in a subpopulation of tumor cells within seven pleomorphic xanthoastrocytomas (PXAs). The expression of glial and neuronal polypeptides was examined in routinely prepared surgical resections by immunohistochemistry using well-characterized antibodies that recognize glial fibrillary acidic protein (GFAP), synaptophysin (SYN), and neurofilament triplet polypeptides (NFPs) in microwave-enhanced single- and double-immunolabelling experiments. Each neoplasm contained cells that were immunoreactive for SYN and/or NFPs, GFAP, and occasionally for both GFAP and either NFP or SYN. We conclude that abortive neuronal/neuroendocrine differentiation may occur in PXAs, suggesting a relationship between PXA and other developmental neoplasms that reveal a more overt neuronal phenotype, such as ganglioglioma, dysembryoplastic neuroepithelial tumor, and desmoplastic ganglioglioma, and with tumors expressing ambiguous glial/neuronal lineage, such as the subependymal giant cell tumor of tuberous sclerosis. These findings suggest that aberrant expression and accumulation of neuronal intermediate filaments may account for the large, pleomorphic cell morphology observed in many of these tumors.

Delayed occurrence of cerebellar pleomorphic xanthoastrocytoma after supratentorial pleomorphic xanthoastrocytoma removal. Case report.

The authors report the case of a 36-year-old woman who underwent gross total resection of a right cerebellar pleomorphic xanthoastrocytoma with atypical features. She had undergone surgery 16 years previously for what was thought to be a right frontal glioblastoma multiforme. In retrospect, based on the histopathology and the clinical course, both lesions were considered to represent atypical variants of pleomorphic xanthoastrocytoma. This report examines the histological and clinical characteristics of this posterior fossa lesion, which exhibited histologically malignant features but has run a relatively indolent course.

Vascular malformations presenting as spinal cord neoplasms: case report.

Three cases of adult patients with subacute courses of progressive caudal spinal cord disease are presented. Computed tomography, magnetic resonance imaging, and myelographic studies were interpreted preoperatively as representing a spinal cord neoplasm in each case. No evidence of enlarged or abnormal surface vessels was observed by neuroimaging or intraoperatively. Biopsy specimens from each spinal cord lesion showed the typical histopathological features of a spinal vascular malformation. We conclude that vascular malformations of the caudal spinal cord can appear as isolated intramedullary lesions with apparently normal surface vessels and that these lesions may be difficult to distinguish from spinal cord neoplasms.

Granulomatous angiitis of the spinal cord: a case report.

A 12-year-old caucasian boy presented with a thoracic myelopathy. Magnetic resonance T1-weighted images revealed an enhancing lesion infiltrating the lower thoracic spinal cord to the level of the conus. Evaluation of the lesion by open biopsy revealed granulomatous angiitis of the spinal cord. Granulomatous angiitis is a rare vasculitic process that typically involves the brain and, less frequently, the spinal cord. Diagnosis must be established early by histopathological examination so that treatment with corticosteroids and/or cytotoxic agents may be instituted. When left untreated, patients with granulomatous angiitis of the spinal cord have developed fatal intracranial manifestations.

Value of thallium-201 SPECT imaging in childhood brain tumors.

Thallium-201 chloride single photon emission computed tomography (201Tl SPECT) has been proposed as a diagnostic tool in the assessment of patients with brain tumors. We performed SPECT scans coupled with magnetic resonance imaging (MRI) in children with brain tumors to determine the sensitivity and potential value of SPECT in neuro-oncology. Each patient was injected with 2.5-3.0 mCi of thallium chloride, followed by technetium-99m HMPAO (5-15 mCi) to assess cerebral perfusion. 201Tl uptake was imaged with triple-headed SPECT in 20/24 (83%) histologically and anatomically diverse neoplasms with MRI-measurable residual disease, including 13/16 (80%) posterior fossa tumors. 201Tl SPECT demonstrated uptake in tumors with MRI volumes ranging from 0.03 to 60 cm3. 201Tl SPECT imaging was not correlated with the following MRI features: gadolinium enhancement, necrosis, exophytic, unicentric and multicentric. 201Tl uptake was not detectable in patients with tumors of maldevelopmental origin or radionecrosis. It is suggested that 201Tl SPECT is an important imaging adjunct in the assessment of children with brain tumors.

Brainstem and other malignant gliomas: II. Possible mechanisms of brain infiltration by tumor cells.

Gliomas that arise in the brain stem and other malignant gliomas constitute approximately 60% of all brain tumors and have eluded effective therapy, in part because they are able to infiltrate the normal brain. Histopathologic studies have confirmed the presence of infiltrating tumor cells very distant from the glioma mass. We review the neuroimaging and pathologic features of glioma-cell infiltration and some of the complex cellular and biochemical determinants of tumor-cell motility and invasiveness. Understanding how glioma cells become motile and invasive is pivotal to therapeutically targeting the machinery that enables gliomas to infiltrate the brain.

Brainstem glioma: I. Pathology, clinical features, and therapy.

Gliomas that arise in the brain stem have been associated with a poor prognosis. Diagnostic neuroimaging readily identifies the tumor as it extends between normal brainstem structures. Histologic sampling of tumor with stereotactic methods is notoriously unreliable in establishing a definitive prognosis. Clinical trials that incorporate high-dose chemotherapy, autologous bone marrow rescue, and irradiation hold promise of better tumor control by overcoming the inaccessibility of the central nervous system to standard doses of chemotherapy. We review the pathology, clinical features, neuroimaging features, and current therapeutic concepts relative to brainstem glioma. The pediatric neurologist has a pivotal role in identifying and monitoring children with this malignancy.

Opportunistic cerebral vasculopathy and stroke in patients with the acquired immunodeficiency syndrome.

OBJECTIVE: To describe an unusual cause of stroke in patients with the acquired immunodeficiency syndrome. DESIGN: An observational case series of hospitalized patients with subsequent autopsy. MEASURES: Clinical, radiological, and pathological examinations were performed. RESULTS: In three of 14 patients with stroke, the infarctions were secondary to an opportunistic vasculopathy caused by Candida albicans, cytomegalovirus, or lymphoma. CONCLUSION: Opportunistic conditions may lead to vascular abnormalities and subsequent stroke in patients with the acquired immunodeficiency syndrome.

Clinicopathologic correlates in Alzheimer disease: assessment of clinical and pathologic diagnostic criteria.

The neuropathologic findings from a group of 123 patients who have come to autopsy from the Rochester Alzheimer Disease Project (RADP) are presented. Among these 123 cases, there were 94 demented subjects who met the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer Disease and Related Disorders Association (NINCDS-ADRDA) clinical criteria for the diagnosis of "probable Alzheimer disease," and 29 normal elderly controls. Autopsy confirmation of Alzheimer disease (AD) was based on the age-graded National Institutes of Health (NIH) consensus conference pathologic criteria. Using the NINCDS-ADRDA clinical criteria and the NIH pathologic criteria, the diagnostic accuracy was 88%, the sensitivity was 98%, and the specificity was 69%. Additional strict clinical and pathologic criteria developed by the RADP were applied in the final review of these cases to exclude all confounding causes of dementia, including cerebral infarcts. After applying these additional criteria, a subset of 62 cases of "pure" AD and "pure" control subjects was identified for a more detailed examination of neuritic plaques (NP) and neurons containing neurofibrillary tangles (NFT). The NP and NFT were counted in three subfields of hippocampus and two areas of association neocortex. The density of diffuse plaques (plaques lacking dystrophic neurites) was estimated on a semiquantitative basis. Results show that the AD patients and control groups could be distinguished from each other easily on the basis of mean NP and NFT counts, but there was sufficient overlap in the counts to present difficulty in diagnosing any individual case. Abundant diffuse plaque involvement and NFT in the neocortex were, however, seen only in AD cases.

Human immunodeficiency virus type 1 infection of neural xenografts.

Human immunodeficiency virus type 1 (HIV-1) infection is highly specific for its human host. To study HIV-1 infection of the human nervous system, we have established a small animal model in which second-trimester (11 to 17.5 weeks) human fetal brain or neural retina is transplanted to the anterior chamber of the eye of immunosuppressed adult rats. The human xenografts vascularized, formed a blood-brain barrier, and differentiated, forming neurons and glia. The xenografts were infected with cell-free HIV-1 or with HIV-1-infected human monocytes. Analysis by polymerase chain reaction revealed HIV-1 sequences in DNA from xenograft tissue exposed to HIV-1 virions, and in situ hybridization demonstrated HIV-1 mRNA localized in macrophages and multinucleated giant cells. Pathological damage was observed only in neural xenografts containing HIV-1-infected human monocytes, supporting the hypothesis that these cells mediate neurotoxicity. This small animal model allows the study of direct and indirect effects of HIV-1 infection on developing human fetal neural tissues, and it should prove useful in evaluating antiviral therapies, which must ultimately target HIV-1 infection of the brain.

In situ hybridization of calcium/calmodulin dependent protein kinase II and tau mRNAs; species differences and relative preservation in Alzheimer's disease.

Abnormal phosphorylation of the microtubule associated protein tau component of neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) may result from alterations in protein kinase expression. Calcium/calmodulin dependent protein kinase II (CaM kinase II) has been shown to phosphorylate tau in vitro in such a way to decrease its electrophoretic mobility. A68, apparently a modified form of tau in AD brain, also shows abnormal phosphorylation and slower mobility than tau. To further examine the role of CaM kinase II in AD, in situ hybridization studies were performed on tissues from rat, monkey and human to examine and compare the patterns of CaM kinase II mRNA expression in different brain regions. The most notable differences among the three species were observed in dendrites in layer I of isocortex, in the molecular layer of the dentate gyrus and stratum radiatum and stratum lacunosum-moleculare in hippocampus, where hybridization was detected in rat, but not in monkey or human brain. In addition, comparisons between tau and CaM kinase II mRNA expression were made in tissue from normal aged adults and AD patients, especially in areas prone to NFT formation. CaM kinase II and tau mRNAs were co-expressed in many neuronal populations, both those which are prone to NFT formation as well as those which are rarely affected by AD changes. No major differences in the relative abundance of either CaM kinase II or tau mRNA within particular neuronal populations was noted between normal aged and AD brain. Diminished hybridization was associated with serve neuronal pathology and cell loss.

Multiple sclerosis masquerading as a mass lesion.

Six patients presenting with new neurological deficits underwent magnetic resonance imaging (MRI) that displayed mass lesions leading to diagnoses of tumor or abscess. Biopsy revealed demyelinating lesions.