Genome-wide brain DNA methylation analysis suggests epigenetic reprogramming in Parkinson disease.

OBJECTIVE: Given the known strong relationship of DNA methylation with environmental exposure, we investigated whether brain regions affected in Parkinson disease (PD) were differentially methylated between PD cases and controls. METHODS: DNA chip arrays were used to perform a genome-wide screen of DNA methylation on the dorsal motor nucleus of the vagus (DMV), substantia nigra (SN), and cingulate gyrus (CG) of pathologically confirmed PD cases and controls selected using the criteria of Beecham et al. Analysis examined differentially methylated regions (DMRs) between cases and controls for each brain area. RNA sequencing and pathway analysis were also performed for each brain area. RESULTS: Thirty-eight PD cases and 41 controls were included in the analysis. Methylation studies revealed 234 significant DMR in the DMV, 44 in the SN, and 141 in the CG between cases and controls (Sidak p < 0.05). Pathway analysis of these genes showed significant enrichment for the Wnt signaling pathway (FDR < 0.01). CONCLUSIONS: Our data suggest that significant DNA methylation changes exist between cases and controls in PD, especially in the DMV, one of the areas affected earliest in PD. The etiology of these methylation changes is not yet known, but the predominance of methylation changes occurring in the DMV supports the hypothesis that vagus nerve function, perhaps involving the gastrointestinal system, is important in PD pathogenesis. These data also give independent support that genes involved in Wnt signaling are a likely factor in the neurodegenerative processes of PD.

Frozen section evaluation via dynamic real-time nonrobotic telepathology system in a university cancer center by resident/faculty cooperation team.

Frozen section telepathology interpretation experience has been largely limited to practices with locations significantly distant from one another with sporadic need for frozen section diagnosis. In 2010, we established a real-time nonrobotic telepathology system in a very active cancer center for daily frozen section service. Herein, we evaluate its accuracy compared to direct microscopic interpretation performed in the main hospital by the same faculty and its cost-efficiency over a 1-year period. From 643 (1,416 parts) cases requiring intraoperative consultation, 333 cases (690 parts) were examined by telepathology and 310 cases (726 parts) by direct microscopy. Corresponding discrepancy rates were 2.6% (18 cases: 6 [0.9%] sampling and 12 [1.7%] diagnostic errors) and 3.2% (23 cases: 8 [1.1%] sampling and 15 [2.1%] diagnostic errors), P = .63. The sensitivity and specificity of intraoperative frozen diagnosis were 0.92 and 0.99, respectively, in telepathology and 0.90 and 0.99, respectively, in direct microscopy. There was no correlation of error incidence with postgraduate year level of residents involved in the telepathology service. Cost analysis indicated that the time saved by telepathology was $19,691.00 over 1 year of the study period, whereas the capital cost for establishing the system was $8,924.00. Thus, real-time nonrobotic telepathology is a reliable and easy-to-use tool for frozen section evaluation in busy clinical settings, especially when frozen section service involves more than one hospital, and it is cost-efficient when travel is a component of the service.

Occipital calcified pseudoneoplasms of the neuraxis (CAPNON): understanding a rare pathology.

Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare and typically benign lesions that can occur anywhere within the central nervous system. Aetiology of this lesion is unclear and surgical removal is usually curative. We present a 24-year-old male patient with a history of occipital migraines who was admitted after sudden onset seizure and loss of vision. CT and MRI demonstrated a small calcifying lesion in the right temporo-occipital lobe. The patient underwent gross total resection of the tumour mass and pathological analysis revealed a CAPNON. The preoperative diagnosis of CAPNON remains difficult due to unspecific radiological findings, yet a clear understanding of characteristic pathological findings and prognosis of CAPNON remains paramount.

The contribution of HIV infection to intracranial arterial remodeling: a pilot study.

Pathological arterial wall changes have been cited as potential mechanisms of cerebrovascular disease in the HIV population. We hypothesize that dilatation would be present in arterial walls of patients with HIV compared to controls. Fifty-one intracranial arteries, obtained from autopsies of five individuals with HIV infection and 13 without, were fixed, embedded, stained, and digitally photographed. Cross-sectional areas of intima, media, adventitia and lumen were measured by preset color thresholding. A measure of arterial remodeling was obtained by calculating the ratio between the lumen diameter and the thickness of the arterial wall. Higher numbers indicate arterial dilatation, while lower numbers indicate arterial narrowing. HIV-infected brain donors were more frequently black (80% vs. 15%, P = 0.02) compared with uninfected donors. Inter and intra-reader agreement measures were excellent. The continuous measure of vascular remodeling was significantly higher in the arteries from HIV donors (ß = 2.8, P = 0.02). Adjustments for demographics and clinical covariates strengthen this association (ß = 9.3, P = 0.01). We found an association of HIV infection with outward brain arterial remodeling. This association might be mediated by a thinner media layer. The reproduction of these results and the implications of this proposed pathophysiology merits further study.

Tuberculoma of the brain with unknown primary infection in an immunocompetent host.

Isolated cerebral tubercular abscess is uncommon in immunocompetent hosts. Our patient had a tuberculoma with no known primary and an atypical MRI appearance. We present a 67-year-old African-American male with complex partial seizures. A CT scan of the brain revealed a new right frontal mass which was not found on imaging two years prior. In view of the patient's age and absence of any known primary malignancy, a primary brain tumor was considered to be the likely diagnosis. On MRI, the mass did not display ring enhancement or necrosis. Rather, the mass was lobulated, with near-uniform enhancement of the lesion with a surrounding high fluid-attenuated inversion recovery signal predominantly in the right frontal region, which extended inferiorly to the parietal region. The lesion showed a few punctate foci of low signal intensity on gradient echo MRI sequences, suggestive of hemorrhage. The mode of infection is unknown. However, it is important to include tuberculosis as a differential diagnosis, especially if the lesion appears to be non-primary, if a primary neoplasm or other metastases are not identified on further investigation, and in a patient of African-American ethnicity. To our knowledge, this is the first record of an isolated tubercular abscess of the brain in a developed country.

Thinning of the arterial media layer as a possible preclinical stage in HIV vasculopathy: a pilot study.

BACKGROUND AND PURPOSE: The purpose of this study was to determine if postmortem intracranial arteries from donors with HIV without stroke have thinner media layers compared with patients without HIV and without stroke. METHODS: Cross-sectional cuts from intracranial arteries were stained with van Gieson and hematoxylin and eosin. Arteries were examined for thickness of each arterial layer. Univariable and multivariable models were used for statistical analyses with probability values <0.05 considered significant. RESULTS: A total of 18 brains were analyzed, 5 with HIV and 13 without. Fifty-five arteries were collected, 15 from HIV brains and 40 from unaffected controls. In univariable analysis, in arteries from HIV-infected brains, the media to wall thickness ratio was smaller than in donors without HIV (0.496 versus 0.563, P=0.017). In multivariable analysis, HIV infection was the only independent predictor of smaller media ratios compared with the same-aged control subjects (P=0.049) but not with aged control subjects (P=0.081). CONCLUSIONS: In patients with HIV without clinical stroke, the media arterial layer is thinner than in patients without HIV. This suggests that a thinner media layer might be a preclinical stage in the development of HIV-related vasculopathy.

Restricted Diffusion of Pus in the Subarachnoid Space: MRSA Meningo-Vasculitis and Progressive Brainstem Ischemic Strokes - A Case Report.

Extra-axial restriction on diffusion weighted imaging (DWI) is an unusual finding on brain magnetic resonance imaging (MRI). Intra-axial restriction on DWI, however, is common, and can represent brain parenchymal infarction, tumor, abscess, or toxic-metabolic process. The infrequency of extra-axial DWI restriction and the paucity of clinico-pathological correlation in the literature limit its differential diagnosis. Scant case reports suggest that extra-axial DWI restriction could be a lymphoma, neurenteric cyst, or, in one patient, subdural empyema [1,2,3]. We postulate that pus formation must be excluded first, because it can provoke an aggressive meningo-vasculitis with rapidly fatal, intra-axial infarctions. Our patient was a 45-year-old man, presenting to our hospital with left facial droop and right (contralateral) arm and leg weakness. Initial MRI revealed DWI restriction in the left lateral pons, consistent with a classic Millard-Gubler stroke. Also noted was a subtle, extra-axial area of curvilinear diffusion restriction in the left cerebellar-pontine angle's subarachnoid space. Days later, the patient had a headache, and repeat MRI revealed extension of the two DWI lesions - both the intra-axial pontine infarction and the extra-axial area of restricted diffusion in the subarachnoid space. The patient became comatose, a third MRI revealed more extensive DWI restrictions, and he expired despite aggressive care. Autopsy revealed massive brainstem infarcts, a thick lymphoplasmacytic infiltrate, copious Gram-Positive cocci (likely MRSA) and arteries partially occluded with fibrointimal proliferation. This emphasizes the concept that extra-axial DWI restriction can represent pus development in the subarachnoid space - a radiographic marker to identify a patient at risk for demise due to septic, meningo-vasculitic infarctions.

Safety and pharmacokinetic analysis of methotrexate administered directly into the fourth ventricle in a piglet model.

We have developed a piglet model to assess chemotherapy administration directly into the fourth ventricle as a potential treatment for medulloblastoma and other malignant posterior fossa tumors. The objective of this study was to assess safety and pharmacokinetics after methotrexate infusions into the fourth ventricle. Catheters were inserted into the fourth ventricle and lumbar cistern in five piglets. Two milligrams of Methotrexate (MTX) was infused into the fourth ventricle on five consecutive days. Safety was assessed by neurological examination, 4.7 T MRI, and post-mortem pathological analysis. MTX levels in serum and cerebrospinal fluid (CSF) were measured, and area under the concentration-time curve (AUC) was calculated for CSF samples. No neurological deficits were caused by MTX infusions. One piglet died from complications of anesthesia induction for MRI scanning. MRI scans showed accurate catheter placement without signal changes in the brainstem or cerebellum. One piglet had asymptomatic ventriculomegaly. Pathological analysis demonstrated meningitis and choroid plexitis consisting predominantly of CD-3 positive T-lymphocytes in all piglets and a small focal area of subependymal necrosis in one. In all piglets, mean peak MTX level in fourth ventricular CSF exceeded that in lumbar CSF by greater than five-fold. Serum MTX levels were undetectable or negligible. Statistically significant differences between fourth ventricle and lumbar AUC were detected at peaks (P = 0.01) and at all collection time points (P = 0.01) but not at troughs (P = 0.36). MTX can be infused into the fourth ventricle without clinical or radiographic evidence of damage. An inflammatory response without clinical correlate is observed. Significantly higher peak MTX levels are observed in the fourth ventricle than in the lumbar cistern.

Pharmacokinetic analysis of etoposide distribution after administration directly into the fourth ventricle in a piglet model.

We hypothesize that infusion of chemotherapeutic agents directly into the fourth ventricle potentially may play a role in treating malignant posterior fossa brain tumors. Accordingly, we used a piglet model developed in our laboratory to test the safety of etoposide infusions into the fourth ventricle and to study the pharmacokinetics associated with these infusions. In 5 piglets, closed-tip silicone catheters were inserted into the fourth ventricle and lumbar cistern. Five consecutive daily infusions of etoposide (0.5 mg) were administered via the fourth ventricle catheter. Serum and CSF from both catheters were sampled for measurement of etoposide level by reversed-phase high performance liquid chromatography (HPLC). For CSF samples, area under the concentration-time curve (AUC) was calculated. Piglets underwent daily neurological examinations, a 4.7 Tesla MRI scan, and then were sacrificed for post-mortem brain examination. No neurological deficits or signs of meningitis were caused by intraventricular chemotherapy infusions. MRI scans showed catheter placement within the fourth ventricle but no signal changes in the brain stem or cerebellum. In all piglets, the mean fourth ventricular CSF peak etoposide level exceeded the mean peak lumbar etoposide levels by greater than 10-fold. Statistically significant differences between fourth ventricle and lumbar AUC were noted at peaks (DeltaAUC = 3384196 ng h/ml with 95%CI: 1758625, 5009767, P = 0.0044) and at all collection time points (DeltaAUC = 1422977 ng h/ml with 95%CI: 732188, 2113766, P = 0.0046) but not at troughs (DeltaAUC = -29546 ng h/ml (95%CI: -147526, 88434.2, P = 0.5251). Serum etoposide was absent at two and four hours after intraventricular infusions in all animals. Pathological analysis demonstrated meningitis, choroid plexitis, and ependymitis in the fourth and occasionally lateral ventricles. Etoposide can be infused directly into the fourth ventricle without clinical or radiographic evidence of damage. Autopsy examination revealed ventriculitis and meningitis which did not have a clinical correlate. Etoposide does not distribute evenly throughout CSF spaces after administration into the fourth ventricle, and higher peak CSF levels are observed in the fourth ventricle than in the lumbar cistern.

Successful application of hyperbranched multidisplacement genomic amplification to detect HIV-1 sequences in single neurons removed from autopsy brain sections by laser capture microdissection.

To confirm studies suggesting that HIV-1 infects neurons and to determine whether CD8(+) T lymphocytes traffic to HIV-1-infected neurons, we used laser capture microdissection to remove hippocampal neurons with and without perineuronal CD8(+) T cells from AIDS patients with HIV-1 encephalitis (HIVE) or without HIVE and from normal controls. We used hyperbranched multidisplacement amplification for whole gene amplification (MDA-WGA) plus two rounds of PCR to amplify housekeeping sequences (HK(+)) and, in HK(+) samples, to amplify HIV-1 gag, nef, and pol sequences. Sample size and, in single neurons, MDA-WGA correlated with housekeeping gene amplification (P < 0.05), whereas patient group and postmortem interval did not (P > 0.05). Neuronal viral sequences correlated with HIVE (43% vs. 13% and 0 in non-HIVE and controls, respectively) and, in HIVE cases, with perineuronal CD8(+) T lymphocytes (70% in CD8(+) samples vs. 37% of CD8(-) samples). Our results suggest that MDA-WGA is a useful technique when analyzing DNA from single cells from autopsy brains, supporting prior studies that show that neurons may contain HIV-1 neuronal sequences in vivo. The association between neuronal infection and perineuronal CD8(+) T cells supports our hypothesis that these cells specifically traffic to infected neurons but raises the possibility that CD8(+) T cells, if infected, could transmit virus to neurons.

Chemotherapy administration directly into the fourth ventricle in a new piglet model. Laboratory Investigation.

OBJECT: The authors hypothesized that chemotherapy infusions directly into the fourth ventricle may potentially play a role in treating malignant posterior fossa tumors. In this study the safety and pharmacokinetics of etoposide administration into the fourth ventricle was tested using an indwelling catheter in piglets. METHODS: A closed-tip silicone lumbar drain catheter was inserted into the fourth ventricle via a posterior fossa craniectomy and 5 daily infusions of etoposide (0.5 mg in 5 animals) or normal saline (in 2 animals) were instilled. Piglets (10-18 kg, 2-3 months of age) underwent daily neurological examinations and 4.7-T magnetic resonance (MR) imaging after the final infusion and were then killed for postmortem examination. Pharmacokinetics were studied using reversed-phase high-performance liquid chromatography on cerebrospinal fluid (CSF) samples at 0.25, 1, 2, 4, 8, 12, and 24 hours after etoposide infusion. Peak and trough CSF etoposide levels were measured for each subsequent infusion. Serum etoposide levels were obtained at 2 and 4 hours after infusion. RESULTS: All piglets remained neurologically intact, and MR images demonstrated catheter placement within the fourth ventricle without signal changes in the brainstem or cerebellum. Serum etoposide was absent at 2 and 4 hours after intraventricular infusions. When adequate samples could be obtained for analysis, CSF etoposide levels peaked 15 minutes after infusion and progressively decreased. Cytotoxic levels (> 0.1 microg/ml) were maintained for 5 consecutive peak and trough measurements with 1 exception. Etoposide-related neuropathology included moderate-to-severe T-lymphocytic meningitis and fourth and lateral ventricular choroid plexitis with associated subependymal inflammation. CONCLUSIONS: Etoposide can be infused directly into the fourth ventricle without clinical or imaging evidence of damage. Cytotoxic CSF etoposide levels can be maintained for 24 hours with a single daily infusion into the fourth ventricle using an indwelling catheter. Intraventricular etoposide elicits an inflammatory response, the long-term effects of which are as yet undetermined.

Multifocal glioblastoma multiforme with synchronous spontaneous hemorrhage: case report.

We report a 65 year old man who presented with left hemiparesis, and was found to have multiple, discrete, peripherally enhancing, hemorrhagic intra-axial masses in the right hemisphere of the brain. Workup for malignancy elsewhere in the body was negative, and biopsy confirmed glioblastoma multiforme. The patient responded clinically to treatment with radiation therapy and temozolomide. We discuss the unusual aspects of this case and stress the importance of tissue diagnosis in managing suspected intracranial malignancies.

Brain CD8+ and cytotoxic T lymphocytes are associated with, and may be specific for, human immunodeficiency virus type 1 encephalitis in patients with acquired immunodeficiency syndrome.

CD8+ T cells infiltrate brains with human immunodeficiency virus type-1 (HIV-1) encephalitis (HIVE) and related animal models; their perineuronal localization suggests cytotoxic T cell (CTL)-mediated neuronal killing. Because CTLs have not been identified in acquired immunodeficiency syndrome (AIDS) brains, the authors identified their cytotoxic granules in autopsy AIDS brains with HIVE and without HIVE (HIVnE) plus controls (7 to 13 cases/group) and determined gene expression profiles of CTL-associated genes in a separate series of cases. CD3+ and CD8+ T cells were significantly increased (P < .01) in perivascular spaces and inflammatory nodules in HIVE but were rare or absent in brain parenchyma in HIVnE and control brains. Eight HIVE brains contained granzyme B+ T cells and five contained perforin+ T cells. Their T-cell origin was confirmed by colocalization of CD8 and granzyme B in the same cell and the absence of CD56+ natural killer cells. The CTLs directly contacted with neurons, as the authors showed previously for CD3+ and CD8+ T cells. CTLs were rare or absent in HIV nonencephalitis (HIVnE) and controls. Granzyme B and H precursor gene expression was up-regulated and interleukin (IL)-12A precursor, a maturation factor for natural killer cells and CTLs, was down-regulated in HIVE versus HIVnE brain. This study demonstrates, for the first time, CTLs in HIVE and shows that parenchymal T cells and CTLs are sensitive biomarkers for HIVE. Consequently, CD8+ T cells and CTLs could mediate brain injury in HIVE and may represent an important biomarker for productive brain infection by HIV-1.

Expression of the antiapoptotic proteins clusterin and bcl-2 in laryngeal squamous cell carcinomas.

Bcl-2 and clusterin genes have been related to the inhibition of apoptosis, an event that plays a key role in malignant transformation and in invasive disease. In this work, we determine the significance of clusterin and bcl-2 expression in a large series of laryngeal carcinomas. We used immunohistochemical methods and in situ hybridization to examine the expression of these proteins. Nontumoral epithelial laryngeal tissues did not express clusterin and bcl-2 proteins. However, 9% (14 out of 154) and 25% of these tumors (39 of 154) had positive clusterin and bcl-2 staining, respectively. Clusterin expression was significantly related to the degree of local invasion and higher bcl-2 expression was found in these clusterin-positive tumors (p < 0.05). Bcl-2 expression was significantly correlated with supraglottic localization, nodal metastases, invasion in depth, and poorly differentiated tumors. However, by multivariate analysis, bcl-2 was shown to be an independent predictor of good prognosis in these tumors (OR = 0.12, 95% CI = 0.02-0.91). These findings indicate that clusterin and bcl-2 are upregulated in laryngeal carcinomas and their expression is related to the invasiveness of these tumors.

Isolated cerebral mucormycosis: report of a case and review of the literature.

Isolated cerebral mucormycosis is a rare but life-threatening infection that generally occurs in patients with intravenous drug abuse or immune deficiency. We report a case of primary cerebral mucormycosis in a healthy adult. Whole body autopsy in this case revealed cerebral mucormycosis with prominent vascular pathology and hemorrhagic necrosis. No nasal sinus, orbital or other primary locus of fungus infection was discovered. Review of the previously reported 30 cases of isolated cerebral mucormycosis revealed associated systemic predisposition in 11 patients and history of intravenous drug abuse in 17 cases. In the remaining two cases, the diagnosis of fungal infection was made only after surgical exploration. Early tissue diagnosis and the consequent surgical excision of the necrotic tissue and aggressive antifungal therapy might salvage life in this fatal condition.

Selective vulnerability of preterm white matter to oxidative damage defined by F2-isoprostanes.

Periventricular white matter injury (PWMI) is the leading cause of cerebral palsy and chronic neurological disability in survivors of prematurity. Despite the large number of affected children, the pathogenetic mechanisms related to PWMI remain controversial. Through studies of 33 human autopsy brains, we determined that early PWMI was related to oxidative damage that particularly targeted the oligodendrocyte lineage, whereas other neuronal and glial cell types were markedly more resistant. F(2)-isoprostanes, an arachidinate metabolite/lipid peroxidation marker of oxidative damage, were significantly increased in early PWMI lesions but not in cerebral cortex. That deleterious lipid peroxidation accompanied early PWMI was supported by similar increases in F(2)-isoprostanes levels in the cerebral cortex from term infants with hypoxic-ischemic cortical injury. Detection of F(4)-neuroprostanes, a neuronal-specific oxidative damage marker, confirmed that neuroaxonal elements were resistant to injury in cerebral cortex and white matter. Significant protein nitration was not detected in PWMI lesions by 3-nitrotyrosine staining. Significant cellular degeneration was confirmed in early PWMI lesions by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling and a marked depletion of oligodendrocyte progenitors of 71 +/- 8%. Hence, the predilection of preterm infants for PWMI is related to selective lipid peroxidation-mediated injury of cerebral white matter and targeted death of oligodendrocyte progenitors.

Compartmentalization of HIV-1 in the central nervous system: role of the choroid plexus.

OBJECTIVES: To determine the genetic and phenotypic composition of HIV-1 found in the choroid plexus (CPx) and its relationship to virus in the brain and peripheral lymphoid tissue. DESIGN: Phenotypic and molecular comparisons of HIV-1 found in autopsy brain, CPx, and spleen tissues. METHODS: HIV-1 was co-cultured from matched postmortem brain (basal ganglia), CPx, and spleen tissues of AIDS patients with and without HIV-associated encephalitis and dementia. Viral phenotypes were determined by infection of monocyte-derived macrophages, MT-2 or co-receptor-specific cell lines. Viral env and pol sequences were determined from genomic DNA isolated directly from tissues or co-cultures, and phylogenetic comparisons were performed. RESULTS: CCR5-utilization was the most prevalent viral tropism found in all tissues, although spleen isolates also displayed CXCR4 usage. Viruses isolated from CPx consisted of both peripheral and brain-like virus, but were more related phenotypically and genetically to those found in the brain. Mutations found in the pol gene that could confer drug resistance to brain and CPx isolates were similar to those found in the periphery. CONCLUSION: The CPx contained replication-competent virus that was most similar, although distinct, from that found in the brain. It also contained some viruses with high similarity to those of peripheral origin. Compartmentalization of viral env and pol sequences indicated that differential selective pressures exist in each tissue examined. These studies suggest that the CPx may provide an environment that promotes the evolution of drug-resistant strains with central nervous system tropism, although it is unlikely to be a reservoir for archival HIV-1 variants.

Gene expression profiles in microdissected neurons from human hippocampal subregions.

Pyramidal neurons in hippocampal subregions are selectively vulnerable in certain disease states. To investigate, we tested the hypothesis that selective vulnerability in human hippocampus is related to regional differences in neuronal cell death and cell receptor gene expression in CA1 vs. CA3 subregions. We used laser capture microdissection to remove approximately 600 CA1 and 600 CA3 pyramidal neurons each from five fresh-frozen normal post-mortem brains, extracted total RNA and double-amplified mRNA. This was reverse transcribed and labeled for hybridization onto human cDNA array chips containing probes to 10,174 genes and unknown ESTs. RNA from additional microdissections was pooled for replicate hybridizations and quantitative RT-PCR validation. Gene expression differences were few (< 1%). We found 43 enriched genes in CA1 neuronal samples that included peripheral benzodiazipine receptor-associated protein, nicotinic cholinergic receptor, two chemokine receptors (CCR1 and CCR5) and several transcriptional factors. We found 17 enriched genes in the CA3 neuronal samples that included fibroblast growth factor receptor and prostaglandin-endoperoxide synthase 1. We found no differential gene expression for 23 calcium channel proteins; nine transporter proteins; 55 cell death and apoptotic regulator proteins; and an additional 497 cell receptors, including 24 glutamate receptors. Quantitative RT-PCR of four differentially expressed genes confirmed the microarray data. The results confirm the ability to examine gene expression profiles in microdissected neurons from human autopsy brain. They show only minor gene expression differences between two distinct neuronal populations in the hippocampus and suggest that selective hippocampal vulnerability is due to factors other than intrinsic differential expression in glutamate receptors and cell death genes.

Human immunodeficiency virus type 1 compartmentalization in the central nervous system.

HIV-1 replicates in monocyte-derived cells in multiple organ systems; in the central nervous system, productive infection is confined to monocyte lineage cells in the brain. In addition, productive viral infection takes place in the choroid plexus, where the incidence of infection is actually higher than in brain and is present prior to the onset of AIDS and immunosuppression. Restricted or latent infection occurs in astrocytes and neurons. The presence of perineuronal CD4+ lymphocytes, as well as activated microglia, support the potential for a trans-receptor mechanism of viral entry whereas intrinsic gene profiles do not appear to participate in conferring selective neuronal vulnerability or resistance to infection.