Arteriolar neuropathology in cerebral microvascular disease

Cerebral microvascular disease (MVD) is an important cause of vascular cognitive impairment. MVD is heterogeneous in aetiology, ranging from universal ageing to the sporadic (hypertension, sporadic cerebral amyloid angiopathy [CAA] and chronic kidney disease) and the genetic (e.g., familial CAA, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy [CADASIL] and cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy [CARASIL]). The brain parenchymal consequences of MVD predominantly consist of lacunar infarcts (lacunes), microinfarcts, white matter disease of ageing and microhaemorrhages. MVD is characterised by substantial arteriolar neuropathology involving ubiquitous vascular smooth muscle cell (SMC) abnormalities. Cerebral MVD is characterised by a wide variety of arteriolar injuries but only a limited number of parenchymal manifestations. We reason that the cerebral arteriole plays a dominant role in the pathogenesis of each type of MVD. Perturbations in signalling and function (i.e., changes in proliferation, apoptosis, phenotypic switch and migration of SMC) are prominent in the pathogenesis of cerebral MVD, making 'cerebral angiomyopathy' an appropriate term to describe the spectrum of pathologic abnormalities. The evidence suggests that the cerebral arteriole acts as both source and mediator of parenchymal injury in MVD.

Genome sequencing analysis identifies new loci associated with Lewy body dementia and provides insights into its genetic architecture

The genetic basis of Lewy body dementia (LBD) is not well understood. Here, we performed whole-genome sequencing in large cohorts of LBD cases and neurologically healthy controls to study the genetic architecture of this understudied form of dementia, and to generate a resource for the scientific community. Genome-wide association analysis identified five independent risk loci, whereas genome-wide gene-aggregation tests implicated mutations in the gene GBA. Genetic risk scores demonstrate that LBD shares risk profiles and pathways with Alzheimer's disease and Parkinson's disease, providing a deeper molecular understanding of the complex genetic architecture of this age-related neurodegenerative condition.

Mechanisms of Cerebral Microbleeds

Cerebral microbleeds (CMB) are a common MRI finding, representing underlying cerebral microhemorrhages (CMH). The etiology of CMB and microhemorrhages is obscure. We conducted a pathological investigation of CMH, combining standard and immunohistological analyses of postmortem human brains. We analyzed 5 brain regions (middle frontal gyrus, occipital pole, rostral cingulate cortex, caudal cingulate cortex, and basal ganglia) of 76 brain bank subjects (mean age ± SE 90 ± 1.4 years). Prussian blue positivity, used as an index of CMH, was subjected to quantitative analysis for all 5 brain regions. Brains from the top and bottom quartiles (n = 19 each) were compared for quantitative immunohistological findings of smooth muscle actin, claudin-5, and fibrinogen, and for Sclerosis Index (SI) (a measure of arteriolar remodeling). Brains in the top quartile (i.e. with most extensive CMH) had significantly higher SI in the 5 brain regions combined (0.379 ± 0.007 vs 0.355 ± 0.008; p < 0.05). These findings indicate significant coexistence of arteriolar remodeling with CMH. While these findings provide clues to mechanisms of microhemorrhage development, further studies of experimental neuropathology are needed to determine causal relationships.

Intracranial meningioma with carcinoma tumor-to-tumor metastasis: two case reports

Meningiomas have been implicated as the most common primary intracranial tumor to contain tumor-to-tumor metastasis. In the following two case reports, we describe cases of adenocarcinoma and breast carcinoma that metastasized into an intracranial meningioma. The first patient was a 64-year-old man presenting to the emergency department with seizures and loss of consciousness. After a left frontal mass resection, pathology reported a heterogeneous mass consisting of a meningioma and a metastatic adenocarcinoma component. The second patient was a 63-year-old woman presenting with significant vision problems and unstable gait. After a right frontal mass resection, pathology reported a heterogeneous mass consisting of a meningioma and a metastatic breast carcinoma component. Possible explanations for the development of the tumor-to-tumor metastasis are described.

Cerebrovascular pathology in Down syndrome and Alzheimer disease

People with Down syndrome (DS) are at high risk for developing Alzheimer disease (AD) with age. Typically, by age 40 years, most people with DS have sufficient neuropathology for an AD diagnosis. Interestingly, atherosclerosis and hypertension are atypical in DS with age, suggesting the lack of these vascular risk factors may be associated with reduced cerebrovascular pathology. However, because the extra copy of APP leads to increased beta-amyloid peptide (Aβ) accumulation in DS, we hypothesized that there would be more extensive and widespread cerebral amyloid angiopathy (CAA) with age in DS relative to sporadic AD. To test this hypothesis CAA, atherosclerosis and arteriolosclerosis were used as measures of cerebrovascular pathology and compared in post mortem tissue from individuals with DS (n = 32), sporadic AD (n = 80) and controls (n = 37). CAA was observed with significantly higher frequencies in brains of individuals with DS compared to sporadic AD and controls. Atherosclerosis and arteriolosclerosis were rare in the cases with DS. CAA in DS may be a target for future interventional clinical trials.

Case of glioblastoma patient treated with tumor treating fields therapy at recurrence degenerating to sarcoma

Optune^® treatment is a US FDA-approved treatment for glioblastoma (GBM) that employs alternating electric fields. Tumor treating field (TTF) therapy can exert its effects on GBM via cell cycle mitosis disruption and cytokinesis. We describe a patient with recurrent GBM who had disease progression following standard surgical treatment and concomitant chemoradiotherapy, and was found to have sarcomatous transformation after initiation of TTF therapy with bevacizumab. Upon tumor progression, repeat surgical resection revealed transformation into a GFAP-negative, reticulin-positive sarcoma with rhabdomyoid features. The possibility of a causal connection between TTF therapy and sarcomatous transformation needs to be further evaluated. No such case of apparent sarcoma formation in the CNS following chemoradiotherapy and/or TTF treatment for GBM has been reported.

Microinfarcts are common and strongly related to dementia in the oldest-old: The 90+ study

INTRODUCTION

We estimated the prevalence of microinfarcts and their association with dementia in a cohort of oldest-old participants.

METHODS

Participants were from The 90+ Study, a population-based study of people 90 years and older. Dementia diagnoses were assigned postmortem during a consensus conference. Microinfarcts were evaluated in six brain regions.

RESULTS

At death, the 213 participants were on average 97 years old, 69% were women, and 52% had dementia. Of the participants, 51% had microinfarcts and 17% had 3+ microinfarcts. The odds ratio (OR) for dementia was similar for 3+ microinfarcts (OR = 4.75, P < .01) and tangle stage V-VI (OR = 4.70, P < .001). Only microinfarcts in cortical regions (other than occipital) were associated to dementia.

DISCUSSION

In this oldest-old cohort, microinfarcts are common and contribute independently and similarly in magnitude to dementia as tangles. As risk factors for microinfarcts and other dementing pathologies are likely to differ, identifying these factors is crucial to developing prevention strategies for dementia in the oldest-old.

Impact of interventions to reduce Alzheimer's disease pathology on the prevalence of dementia in the oldest-old

INTRODUCTION

The number of persons aged >90 years will grow significantly in coming decades. This group has the highest rates of dementia, most commonly Alzheimer's disease (AD).

METHODS

Using The 90+ Study, we developed a statistical model for dementia risk based on brain pathologies. Intervention scenarios which reduce or eliminate AD pathology were considered, and the numbers of dementia cases among the U.S. oldest-old that could be prevented were estimated.

RESULTS

The U.S. dementia prevalence among the oldest-old will increase from 1.35 million in 2015 to 4.72 million in 2050. If interventions eliminate AD pathology, dementia prevalence would be reduced by approximately 50%, averting nearly 2.4 million cases in 2050. However, large numbers of dementia cases would still remain.

DISCUSSION

Reducing AD pathology would significantly decrease the public health burden of dementia. However, other interventions are needed to address the burden associated with other dementing pathologies prevalent in the oldest-old.

Multiple pathologies are common and related to dementia in the oldest-old: The 90+ Study

OBJECTIVE

The purpose of this study was to examine the role of multiple pathologies in the expression of dementia in the oldest-old.

METHODS

A total of 183 participants of The 90+ Study with longitudinal follow-up and autopsy were included in this clinical-pathologic investigation. Eight pathologic diagnoses (Alzheimer disease [AD], microinfarcts, hippocampal sclerosis, macroinfarcts, Lewy body disease, cerebral amyloid angiopathy, white matter disease, and others) were dichotomized. We estimated the odds of dementia in relation to each individual pathologic diagnosis and to the total number of diagnoses. We also examined dementia severity in relation to number of pathologic diagnoses.

RESULTS

The presence of multiple pathologic diagnoses was common and occurred more frequently in those with dementia compared with those without dementia (45% vs 14%). Higher numbers of pathologic diagnoses were also associated with greater dementia severity. Participants with intermediate/high AD pathology alone were 3 times more likely to have dementia (odds ratio = 3.5), but those with single non-AD pathologies were 12 times more likely to have dementia (odds ratio = 12.4). When a second pathology was present, the likelihood of dementia increased 4-fold in those with intermediate/high AD pathology but did not change in those with non-AD pathologies, suggesting that pathologies may interrelate in different ways.

CONCLUSIONS

In the oldest-old, the presence of multiple pathologies is associated with increased likelihood and severity of dementia. The effect of the individual pathologies may be additive or perhaps synergistic and requires further research. Multiple pathologies will need to be targeted to reduce the burden of dementia in the population.

Brain gene expression patterns differentiate mild cognitive impairment from normal aged and Alzheimer's disease

Mild cognitive impairment (MCI) represents a cognitive state intermediate between normal aging and early Alzheimer's disease (AD). To investigate if the molecular signature of MCI parallels the clinical picture, we use microarrays to extensively profile gene expression in 4 cortical brain regions (entorhinal cortex, hippocampus, superior frontal gyrus, post-central gyrus) using the postmortem tissue from cognitively normal aged controls, MCI, and AD cases. Our data reveal that gene expression patterns in MCI are not an extension of aging, and for the most part, are not intermediate between aged controls and AD. Functional enrichment analysis of significant genes revealed prominent upregulation in MCI brains of genes associated with anabolic and biosynthetic pathways (notably transcription, protein biosynthesis, protein trafficking, and turnover) as well as mitochondrial energy generation. In addition, many synaptic genes showed altered expression in MCI, predominantly upregulation, including genes for central components of the vesicle fusion machinery at the synapse, synaptic vesicle trafficking, neurotransmitter receptors, and synaptic structure and stabilization. These data suggest that there is a rebalancing of synaptic transmission in the MCI brain. To investigate if synaptic gene expression levels in MCI were related to cognitive function, Pearson correlation coefficient between the Mini Mental State Examination (MMSE) and region-specific messenger RNA expression were computed for MCI cases. A number of synaptic genes showed strong significant correlations (r > 0.8, p < 0.01) most notably in the entorhinal cortex, with fewer in the hippocampus, and very few in neocortical regions. The synaptic genes with highly significant correlations were predominantly related to synaptic transmission and plasticity, and myelin composition. Unexpectedly, we found that gene expression changes that facilitate synaptic excitability and plasticity were overwhelmingly associated with poorer MMSE, and conversely that gene expression changes that inhibit plasticity were positively associated with MMSE. These data suggest that there are excessive excitability and apparent plasticity in limbic brain regions in MCI, that is associated with impaired synaptic and cognitive function. Such changes would be predicted to contribute to increased excitability, in turn leading to greater metabolic demand and ultimately progressive degeneration and AD, if not controlled.

Abstract W MP94: Acute Inflammation Expands Cerebral Microbleeds in a Mouse Model of Cerebral Amyloid Angiopathy

Introduction: Cerebral microscopic hemorrhages are the pathologic substrate of cerebral microbleeds (CMB). Little is known about mechanisms of expansion of CMB. Here we studied the dynamics of CMB after acute inflammation, using a transgenic mouse model of cerebral amyloid angiopathy with spontaneous microscopic hemorrhages and endotoxin (lipopolysaccharide, LPS) as an inflammatory stimulus.

Methods: 21-month old Tg2576 mice and wildtype littermates received a single dose of LPS, 100 or 1000 ug/kg i.p., or phosphate-buffered saline (PBS) as control. Mice were sacrificed 48 hours later and brains were collected for the analysis of microscopic hemorrhages, as well as edema formation, blood-brain barrier constituents and glial activation. Differences among groups were tested by anova and contrasts.

Results: Hematoxylin and eosin staining demonstrated no freshly-formed microscopic hemorrhages in LPS-treated mice. Using Prussian blue staining, we found that total area, average size, and number of CMB differed significantly between PBS-treated wildtype and transgenic mice (p=0.03, p=.04 and p=.03 respectively). Acute inflammation did not significantly affect total area, average size, or number of CMB in wildtype animals. For transgenic mice, both doses of LPS significantly (p<.01) increased the total area of Prussian blue-positive lesions (2.2 to 2.9-fold increase), and higher LPS dose significantly (p<.01) increased average size of CMB by 2.6-fold; both average and total size of CMB increased in a dose-dependent manner. IgG and fibrinogen levels significantly increased after high dose LPS injection in both wildtype and transgenic mice (p<.05). Tight junction protein claudin-5 levels were also increased in high dose LPS-treated mice (p<0.05). LPS injection significantly increased expression of activated microglia markers CD45, CD14, and Iba1.

Conclusions: In a mouse model of cerebral amyloid angiopathy, acute inflammatory stimulus induced expansion of CMB without producing fresh hemorrhage. Increased size of CMB was associated with indices of cerebral edema, alteration of tight junction constituents, and microglial activation. These findings suggest that cerebral edema may mediate expansion of cerebral microbleeds.

Brain-derived neurotrophic factor in human subjects with function-altering melanocortin-4 receptor variants

Background

In rodents, hypothalamic brain-derived neurotrophic factor (BDNF) expression appears to be regulated by melanocortin-4 receptor (MC4R) activity. The impact of MC4R genetic variation on circulating BDNF in humans is unknown.

Objective

To compare BDNF concentrations of subjects with loss-of-function (LOF) and gain-of-function (GOF) MC4R variants to those of controls with common sequence MC4R.

Methods

Circulating BDNF was measured in two cohorts with known MC4R sequence: 148 subjects of Pima Indian heritage ([mean±SD]: age 15.7±6.5y, BMI-Z 1.63±1.03), and 69 subjects of Hispanic heritage (10.8±3.6y, BMI-Z 1.57±1.07). MC4R variants were characterized in vitro by cell surface expression, receptor binding, and cAMP response after agonist administration. BDNF single nucleotide polymorphisms (SNPs) rs12291186, rs6265, and rs7124442 were also genotyped.

Results

In the Pima cohort, no significant differences in serum BDNF was observed for 43 LOF-subjects versus 65 LOF-matched controls [age-, sex-, and BMI-matched] (P=0.29), or 20 GOF-subjects versus 20 GOF-matched controls (P=0.40). Serum BDNF was significantly associated with genotype for BDNF rs12291186 (P=0.006) and rs6265 (P=0.009), but not rs7124442 (P=0.99); BDNF SNPs did not interact with MC4R status to predict serum BDNF. In the Hispanic cohort, plasma BDNF was not significantly different among 21 LOF-subjects, 20 GOF-subjects, and 28 controls (P=0.79); plasma BDNF was not predicted by BDNF genotype or BDNF-x-MC4R genotype interaction.

Conclusions

Circulating BDNF concentrations were not significantly associated with MC4R functional status, suggesting that peripheral BDNF does not directly reflect hypothalamic BDNF secretion and/or that MC4R signaling is not a significant regulator of the bulk of BDNF expression in humans.

Bapineuzumab alters aβ composition: implications for the amyloid cascade hypothesis and anti-amyloid immunotherapy

The characteristic neuropathological changes associated with Alzheimer’s disease (AD) and other lines of evidence support the amyloid cascade hypothesis. Viewing amyloid deposits as the prime instigator of dementia has now led to clinical trials of multiple strategies to remove or prevent their formation. We performed neuropathological and biochemical assessments of 3 subjects treated with bapineuzumab infusions. Histological analyses were conducted to quantify amyloid plaque densities, Braak stages and the extent of cerebral amyloid angiopathy (CAA). Amyloid-β (Aβ) species in frontal and temporal lobe samples were quantified by ELISA. Western blots of amyloid-β precursor protein (AβPP) and its C-terminal (CT) fragments as well as tau species were performed. Bapineuzumab-treated (Bapi-AD) subjects were compared to non-immunized age-matched subjects with AD (NI-AD) and non-demented control (NDC) cases. Our study revealed that Bapi-AD subjects exhibited overall amyloid plaque densities similar to those of NI-AD cases. In addition, CAA was moderate to severe in NI-AD and Bapi-AD patients. Although histologically-demonstrable leptomeningeal, cerebrovascular and neuroparenchymal-amyloid densities all appeared unaffected by treatment, Aβ peptide profiles were significantly altered in Bapi-AD subjects. There was a trend for reduction in total Aβ₄₂ levels as well as an increase in Aβ₄₀ which led to a corresponding significant decrease in Aβ₄₂:Aβ₄₀ ratio in comparison to NI-AD subjects. There were no differences in the levels of AβPP, CT99 and CT83 or tau species between Bapi-AD and NI-AD subjects. The remarkable alteration in Aβ profiles reveals a dynamic amyloid production in which removal and depositional processes were apparently perturbed by bapineuzumab therapy. Despite the alteration in biochemical composition, all 3 immunized subjects exhibited continued cognitive decline.

Frontal cortex neuropathology in dementia pugilistica

Dementia pugilistica (DP) is associated with chronic traumatic brain injury (CTBI), and leads to a "punch drunk" syndrome characterized by impairments in memory and executive function, behavioral changes, and motor signs. Microscopic features include the accumulation of neurofibrillary tangles (NFTs), beta-amyloid (Aβ), and TAR DNA binding protein 43 (TDP-43) pathology. Here we describe detailed clinical and neuropathological data about a 55-year-old retired boxer (ApoE3/4), who presented with executive dysfunction and behavioral impairments. At autopsy, significant Aβ pathology was seen, primarily in the form of diffuse plaques. Tau pathology was extensive and was determined to be of Braak and Braak stage VI. Frontal white matter showed evidence of glial tau inclusions (astrocytes and oligodendroglia). Cerebrovascular pathology was minimal with patchy amyloid angiopathy. Inflammation was another key feature, including microglial activation and significant C1q labeling of neurons, along with NFTs. TDP-43-positive pathology was also observed. Inflammation may be a key inciting as well as propagating feature of DP neuropathology.

Primary leptomeningeal plasmablastic lymphoma

Lymphomas that develop in human immunodeficiency virus (HIV) infected patients are predominantly aggressive B-cells lymphomas. The most common HIV-associated lymphomas include Burkitt lymphoma, diffuse large B-cell lymphoma (that often involves the CNS), primary effusion lymphoma, and plasmablastic lymphoma (PBL). Of these, PBL is relatively uncommon and displays a distinct affinity for presentation in the oral cavity. In this manuscript we report a previously undescribed primary leptomeningeal form of PBL in a patient with acquired immunodeficiency syndrome. A 40-year-old HIV positive man presented with acute onset confusion, emesis, and altered mental status. Lumbar puncture showed numerous nucleated cells with atypical plasmocyte predominance. CSF flowcytometry showed kappa restriction with CD8 and CD38 positivity and negative lymphocyte markers, while the MRI showed diffuse leptomeningeal enhancement. As the extensive systemic work-up failed to reveal any disease outside the brain, an en bloc diagnostic brain and meningeal biopsy was performed. The biopsy specimen showed sheets of plasmacytoid cells with one or more large nuclei, prominent nuclear chromatin, scattered mitoses, and abundant cytoplasm, highly suggestive of plasmablastic lymphoma. HIV-associated malignancies have protean and often confusing presentations, which pose diagnostic difficulties posed to the practicing neurological-surgeons. Even in cases where an infectious cause is suspected for the meningeal enhancement, neoplastic involvement should be considered, and cytology and flow-cytometry should be routinely ordered on the CSF samples.

Cerebral microbleeds in the elderly: a pathological analysis

BACKGROUND AND PURPOSE

Cerebral microbleeds in the elderly are routinely identified by brain MRI. The purpose of this study was to better characterize the pathological basis of microbleeds.

METHODS

We studied postmortem brain specimens of 33 individuals with no clinical history of stroke and with an age range of 71 to 105 years. Cerebral microbleeds were identified by presence of hemosiderin (iron), identified by routine histochemistry and Prussian blue stain. Cellular localization of iron (in macrophages and pericytes) was studied by immunohistochemistry for smooth muscle actin, CD68, and, in selected cases, electron microscopy. Presence of β-amyloid was analyzed using immunohistochemistry for epitope 6E10.

RESULTS

Cerebral microbleeds were present in 22 cases and occurred at capillary, small artery, and arteriolar levels. Presence of microbleeds occurred independent of amyloid deposition at site of microbleeds. Although most subjects had hypertension, microbleeds were present with and without hypertension. Putamen was the site of microbleeds in all but 1 case; 1 microbleed was in subcortical white matter of occipital lobe. Most capillary microbleeds involved macrophages, but the 2 microbleeds studied by electron microscopy demonstrated pericyte involvement.

CONCLUSIONS

These findings indicate that cerebral microbleeds are common in elderly brain and can occur at the capillary level.

Altered white matter integrity in temporal lobe epilepsy: association with cognitive and clinical profiles

PURPOSE

Diffusion tensor imaging (DTI) studies have reported substantial white matter abnormalities in patients with temporal lobe epilepsy (TLE). However, limited data exist regarding the extent of white matter tract abnormalities, cognitive effects of these abnormalities, and relationship to clinical factors. The current study examined these issues in subjects with chronic TLE.

METHODS

DTI data were obtained in 12 TLE subjects and 10 age-matched healthy controls. Voxel-wise statistical analysis of fractional anisotropy (FA) was carried out using tract-based spatial statistics (TBSS). White matter integrity was correlated with cognitive performance and epilepsy-related clinical parameters.

RESULTS

Subjects with TLE, as compared to healthy controls, demonstrated four clusters of reduced FA, in anterior temporal lobe, mesial temporal lobe, and cerebellum ipsilateral, as well as frontoparietal lobe contralateral to the side of seizure onset. Mean FA was positively correlated with delayed memory, in anterior temporal lobe; and immediate memory, in mesial temporal lobe. Lower FA values in the posterior region of corpus callosum were related to earlier age of seizure onset.

CONCLUSION

TLE is associated with widespread disturbances in white matter tracts and these changes have important cognitive and clinical consequences.

Isolated amygdala neurocysticercosis in a patient presenting with déjà vu and olfactory auras. Case report

Neurocysticercosis is the most common parasitic infection in the CNS and a leading cause of epilepsy. Since it is a circumscribed lesional cause of epilepsy, specific locations of neurocysticercal lesions may lead to specific clinical presentations. The authors describe a 17-year-old Hispanic boy who had a single enhancing bilobar mass in the right amygdala. Initially, the patient presented with secondarily generalized tonic-clonic seizures, which resolved with antiepilepsy drug therapy. On further investigation, he was found to have persistent olfactory and déjà vu auras. A right amygdalectomy without hippocampectomy was performed, and both the seizures and auras immediately resolved. Pathological analysis revealed neurocysticercosis. To the authors' knowledge, this case is the first reported instance of 2 distinct mesial temporal aura semiologies associated with localized neurocysticercosis in the amygdala and successfully treated with resection. Uniquely, the case demonstrates that both olfactory and déjà vu auras can emanate from the amygdala.

Primary leptomeningeal oligodendrogliomatosis

Primary leptomeningeal oligodendrogliomas (PLOs) are rare intracranial malignancies where tumors grow in the subarachnoid space without an obvious connection to the brain or spinal cord parenchyma. Adding to the three previously reported cases of PLO with no parenchymal involvement we report a fourth case of the same in this paper in a 50-year-old woman presenting with unrelenting headaches. CT scan of her head revealed hydrocephalus and MRI revealed diffuse enhancement of her leptomeninges throughout her brain and spine, prominent over the basilar region. Biopsy obtained using a frameless stereotactic biopsy showed sharply defined cell borders, clear cytoplasm, and rounded nuclei consistent with an oligodendroglioma. Our case suggests that PLO can mimic diffuse forms of granulomatous meningitis and should be suspected in patients that clinically and radiographically present like granulomatous meningitis but without blood or CSF markers for the same.

Synaptic proteins, neuropathology and cognitive status in the oldest-old

An increasing number of individuals in our population are surviving to over 90 years and a subset is at risk for developing dementia. However, senile plaque and neurofibrillary tangle pathology do not consistently differentiate individuals with and without dementia. Synaptic protein loss is a feature of aging and dementia and may dissociate 90+ individuals with and without dementia. Synaptophysin (SYN), postsynaptic density 95 (PSD-95) and growth-associated protein 43 (GAP-43) were studied in the frontal cortex of an autopsy series of 32 prospectively followed individuals (92-105 years) with a range of cognitive function. SYN protein levels were decreased in individuals with dementia and increased in those with clinical signs of cognitive impairment insufficient for a diagnosis of dementia. SYN but neither PSD-95 nor GAP-43 protein levels were significantly correlated with mini-mental status examination (MMSE) scores. Frontal cortex SYN protein levels may protect neuronal function in oldest-old individuals and reflect compensatory responses that may be involved with maintaining cognition.

Acute toxicity pilot evaluation of proliferol in rats and swine

Proliferol is an investigational new drug containing lidocaine hydrochloride 0.25%, dextrose 12.5%, glycerin 12.5%, and phenol 1.0% in aqueous solution. Despite extensive previous experience with similar drug solutions administered in humans by intraligamentous injection for chronic musculoskeletal conditions for over 50 years, animal toxicity data are unavailable. A pilot study was conducted to assess acute toxic effects prior to undertaking further assessment of this drug. Test animals were four Sprague-Dawley rats and four Yucatan mini-swine. Rats received injections into lumbar paraspinal muscles, whereas swine received injections into lumbosacral ligaments in an attempt to mirror the method of administration in humans. Two doses were studied equivalent to 1x and 5x the typical human dose. Outcomes measured at 24 h and 14 days included clinical observations, clinical chemistry, hematology, urinalysis, local tolerance, and major organ histopathology. In rats and swine, results from clinical chemistry, hematology, and urinalysis were indicative of acute local inflammation. At the high dose, marked (rats) and moderate (swine) short-term above-normal levels in certain liver enzymes were noted. In rats and swine, local tolerance results were indicative of acute local inflammatory changes in the skin, subcutis, and muscle around the injection sites. In rats and swine, major organ histopathology results did not reveal lesions attributable to the drug and clinical observations were within normal limits. In swine, fibroplasia was noted in deeper muscle tissues after 14 days. Injections of Proliferol in lumbar paraspinal muscles in rats and lumbosacral ligaments in swine elicited a modest acute local inflammatory response with no other indications of local or systemic toxicity.

Relapsing polychondritis with features of dementia with Lewy bodies

We describe a 72-year old man with clinical features suggestive of dementia with Lewy bodies (DLB) who proved neuropathologically to have degeneration induced by relapsing polychondritis (RP), an autoimmune inflammatory disorder of cartilaginous tissues. There was lymphocytic infiltration of the leptomeninges, perivascular cuffing, reactive astrocytosis, and activation of microglia in multiple brain areas all consistent with an immunologically mediated process. There was widespread neuronal loss within the hippocampus, entorhinal cortex, and amygdala as well as diffuse myelin pallor of cortical pathways. Elevated levels of complement proteins and endothelial markers of inflammation were observed, which are similar to previous reports in DLB. This study demonstrates that qualitatively similar inflammation-associated neurodegeneration is present in widespread regions of the brain in a RP case presenting clinically as DLB.

Acute hemorrhagic leukoencephalitis: neuroimaging features and neuropathologic diagnosis

A case of biopsy-proven acute hemorrhagic leukoencephalitis is reported. The early computed tomography scans showed extensive bilateral hypodensities with mass effects and foci of microhemorrhages. Bilateral asymmetric hyperintensities in the mesiotemporal and frontal lobes and massive edema were found on T2-weighted and fluid-attenuated inversion recovery magnetic resonance images in a pattern classic for herpes simplex encephalitis. This fulminant demyelinating disease progresses to coma and death within days. Early diagnosis with neuroimaging studies and rapid correlation with the clinical findings of this disease are vital for the institution of potentially lifesaving treatments.

Caspase-cleaved tau accumulation in neurodegenerative diseases associated with tau and alpha-synuclein pathology

Alzheimer's disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and dementia with Lewy bodies (DLB) are diseases associated with the accumulation of tau or alpha-synuclein. In AD, beta-amyloid (Abeta)-associated caspase activation and cleavage of tau at Asp421 (DeltaTau) may be an early step in neurofibrillary tangle (NFT) formation. To examine whether DeltaTau accumulates in other diseases not characterized by extracellular Abeta accumulation, we examined PiD, PSP, and CBD cases in comparison to those without extensive tau accumulation including frontotemporal lobar degeneration without Pick bodies (FTLD) and control cases. Additionally, we studied DeltaTau accumulation in DLB cases associated with intracellular alpha-synuclein. DeltaTau was observed in all disease cases except non-PiD FTLD and controls. These results demonstrate that the accumulation of DeltaTau may represent a common pathway associated with abnormal accumulation of intracellular tau or alpha-synuclein and may be relatively less dependent on the extracellular accumulation of Abeta in non-AD dementias.

Living T9 glioma cells expressing membrane macrophage colony-stimulating factor produce immediate tumor destruction by polymorphonuclear leukocytes and macrophages via a "paraptosis"-induced pathway that promotes systemic immunity against intracranial T9 gliomas

Cloned T9-C2 glioma cells transfected with membrane macrophage colony-stimulating factor (mM-CSF) never formed subcutaneous tumors when implanted into Fischer rats, whereas control T9 cells did. The T9-C2 cells were completely killed within 1 day through a mechanism that resembled paraptosis. Vacuolization of the T9-C2 cell's mitochondria and endoplasmic reticulum started within 4 hours after implantation. By 24 hours, the dead tumor cells were swollen and terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL)-positive. Bcl2-transduced T9-C2 cells failed to form tumors in rats. Both T9 and T9-C2 cells produced cytokine-induced neutrophil chemoattractant that recruited the granulocytes into the tumor injection sites, where they interacted with the tumor cells. Freshly isolated macrophages killed the T9-C2 cells in vitro by a mechanism independent of phagocytosis. Nude athymic rats treated with antiasialo GM1 antibody formed T9-C2 tumors, whereas rats treated with a natural killer cell (NK)-specific antibody failed to form tumors. When treated with antipolymorphonuclear leukocyte (anti-PMN) and antimacrophage antibodies, 80% of nude rats formed tumors, whereas only 40% of the rats developed a tumor when a single antibody was used. This suggests that both PMNs and macrophages are involved in the killing of T9-C2 tumor cells. Immunocompetent rats that rejected the living T9-C2 cells were immune to the intracranial rechallenge with T9 cells. No vaccinating effect occurred if the T9-C2 cells were freeze-thawed, x-irradiated, or treated with mitomycin-C prior to injection. Optimal tumor immunization using mM-CSF-transduced T9 cells requires viable tumor cells. In this study optimal tumor immunization occurred when a strong inflammatory response at the injection of the tumor cells was induced.

Optimization of techniques for the maximal detection and quantification of Alzheimer's-related neuropathology with digital imaging

Prior to undertaking quantitative neuropathological studies of Alzheimer's disease, methods for detecting plaques and tangles must be optimized. While suitable antibodies have been developed with great sensitivity, specificity, and reliability, there is no standard pre-treatment protocol for key AD-related pathology. It is well known that formic acid treatment enhances the detection of beta-amyloid. But what concentration of formic acid is best; can similar methods enhance the detection of tau-related pathology? This study compared multiple antigen retrieval techniques (e.g. boiling in citrate or glycine buffer, microwaves, formic acid concentrations), to develop an optimal, standardized protocol for quantitative digital microscopy. Free-floating (40 microm) and paraffin-embedded (12 microm) sections of formalin fixed frontal cortex from mild, moderate, and severe AD cases (n = 18) were pretreated with fifteen different protocols and stained with each of the following antibodies: beta42, PHF-1, MC-1 and AT8. Random fields were digitally captured and images were thresholded to select for positively stained areas versus background (e.g. "load"). As previously reported, high concentrations of formic acid were extremely effective in enhancing the detection of beta-amyloid; as much as a 2-fold enhancement in Abeta "load" values were observed. Surprisingly, tau-related pathology detection also increased significantly following pretreatment. Depending on the antibody, between a 3-fold and 6-fold enhancement was possible relative to no pretreatment. Comparable results were found in paraffin-embedded sections. Similar enhancements in the detection of pathology were obtained following 99% formic acid exposure, microwaving in citrate buffer (pH 9.0) or exposure to 99% formic acid then boiling in citrate buffer (pH 6.0). Because the latter treatments were often harsh on the tissue and more difficult to control, we recommend a standard tissue pretreatment of 99% formic acid for seven minutes for both beta-amyloid and tau-related pathology.

Brainstem and cortical Lewy bodies in patients presenting clinically with Alzheimer's disease

In order to study the clinical overlap between neuropathologically defined Lewy body disease (LBD) and Alzheimer's disease, we examined the brains of 37 demented and 13 non-demented subjects. Nigral Lewy bodies (LBs) were present in 16/37 dementia patients, 13 of which had LBD. Eight of these 13 were clinically indistinguishable from AD patients, and in these cases isocortical neurofibrillary tangle (NFT) formation was rare. Thus, although the two conditions were clinically similar in this series, LBD could be distinguished from AD pathologically not only by the presence of nigral LBs but also by the relative paucity of isocortical NFTs.

T9 glioma cells expressing membrane-macrophage colony stimulating factor produce CD4+ T cell-associated protective immunity against T9 intracranial gliomas and systemic immunity against different syngeneic gliomas

Cloned T9 glioma cells (T9-C2) expressing the membrane form of macrophage colony stimulating factor (mM-CSF) inoculated subcutaneously into rats do not grow and glioma-specific immunity is stimulated. Immunotherapy experiments showed that intracranial T9 tumors present for one to four days could be successfully eradicated by peripheral vaccination with T9-C2 cells. CD4+ and CD8+ T splenocytes from immunized rats, when restimulated in vitro with T9 cells, produced interleukin-2 and -4. Protective immunity against intracranial T9 gliomas could only be adoptively transferred into naive rats by the CD4+ splenocytes obtained from T9-C2 immunized rats. Rats immunized by the T9-C2 tumor cells also resisted two different syngeneic gliomas (RT2 and F98) but allowed a syngeneic NUTU-19 ovarian cancer to grow. Such cross-protective immunity against unrelated gliomas suggests that mM-CSF transfected tumor cells have immunotherapeutic potential for use as an allogeneic tumor vaccine.

Astrocytes degenerate in frontotemporal dementia: possible relation to hypoperfusion

To understand the extent and specificity of astrocyte pathology in sporadic frontotemporal dementia (FTD), we examined several FTD cases for molecular and morphologic characteristics of astrocyte degeneration. We quantified reactive and degenerating astrocytes in sections of frontal, temporal, parietal, and occipital cortex identified using glial fibrillary acidic protein (GFAP) immunoreactivity, terminal deoxynucleotidyl transferase (TdT) labeling, and morphological characteristics and compared them with nondemented, age-matched control brains. Conventional and confocal microscopy revealed that a subpopulation of GFAP(+) astrocytes exhibited positive TdT labeling and beading of their processes in the frontal, temporal, and parietal cortices in 5 of 7 FTD cases that also exhibited gliosis. This morphology was reproduced in cultured astrocytes using ischemic insults. Degenerating astrocytes in FTD correlated inversely with cerebral blood flow as measured by single photon emission computed tomography (SPECT) analysis of (133)Xe inhalation (r = 0.55, p < 0.05). Furthermore, areas of significant astrogliosis corresponded to areas of SPECT hypoperfusion, suggesting that astrocytes may be affected by or perhaps have a causal role in the disturbances of cerebral perfusion in FTD.

Spinal cord infarction following vertebral angiography: clinical and pathological findings

Spinal cord damage from radiographic contrast material has been known to occur in both spinal and nonspinal angiographic procedures. Reported here is cervical spinal cord injury (SCI) during vertebral angiography. During the procedure, the patient displayed signs of acute cervical spinal cord irritation that should have been taken as a warning of impending injury. Autopsy 9 years later showed evidence of central cervical spinal cord necrosis. The pathological findings are similar to those seen in animal models of contrast media-induced SCI; and the pathophysiological mechanisms of such injury are discussed.

Membranous glomerulopathy with Bowman's capsular and tubular basement membrane deposits

Bowman's capsular and tubular basement membrane (TBM) deposits are an extremely unusual finding in non-lupus membranous glomerulopathy (MGN). We report three atypical cases of MGN with abundant Bowman's capsular and TBM deposits. In two cases, MGN was idiopathic; in the third case, MGN occurred in the renal allograft in the setting of HCV seropositivity. In addition to the usual glomerular capillary wall deposits, immunofluorescence and electron microscopy revealed extensive immune deposits within Bowman's capsule and TBMs, predominantly at the base of parietal and tubular epithelial cells. These cases suggest a potential pathomechanism of autoantibody to secreted epithelial antigens shared by visceral, parietal, and tubular epithelial cells. In all three cases, indirect immunofluorescence was unable to detect autoantibody to normal renal epithelial or matrix constituents. Furthermore, ELISA was unable to demonstrate circulating antibody to major extracellular matrix components. The implications of these findings for the pathogenesis of MGN are explored.

Molecular dating of senile plaques in the brains of individuals with Down syndrome and in aged dogs

beta-Amyloid (Abeta) is a constituent of senile plaques found with increasing age in individuals with Down syndrome (DS) and in the canine model of aging. Sections of DS and dog brain were immunostained using an affinity-purified polyclonal antibody for a posttranslationally modified Abeta with a racemized aspartate at position 7 (d7C16). The immunostaining characteristics of d7C16 Abeta in DS and dog brain indicate that it is present in all plaque subtypes, including the thioflavin-S-negative diffuse plaques that develop with age in dogs. The youngest DS case exhibited weak immunolabeling for d7C16 but the extent of d7C16-positive plaques increased with age. In addition, d7C16-positive plaques were initially found in clusters in the superficial layers of the frontal and entorhinal cortex but, with advancing age, increasing numbers appeared in deeper layers, suggesting a progression of Abeta deposition from superficial to deeper cortical layers. Ultrastructural studies in DS brain were confirmed using perfused dog brain and provided consistent results; thioflavin-S-negative diffuse plaques consist of fibrillar Abeta and racemized Abeta is associated with thicker and more highly interwoven fibrils than nonracemized Abeta. The use of antibodies to modified forms of the Abeta protein should provide insight into the progression of plaque pathology in DS and Alzheimer's disease brain.

DNA damage and activated caspase-3 expression in neurons and astrocytes: evidence for apoptosis in frontotemporal dementia

Frontotemporal dementia (FTD) is a neurodegenerative disease which affects mainly the frontal and anterior temporal cortex. It is associated with neuronal loss, gliosis, and microvacuolation of lamina I to III in these brain regions. In previous studies we have described neurons with DNA damage in the absence of tangle formation and suggested this may result in tangle-independent mechanisms of neurodegeneration in the AD brain. In the present study, we sought to examine DNA fragmentation and activated caspase-3 expression in FTD brain where tangle formation is largely absent. The results demonstrate that numerous nuclei were TdT positive in all FTD brains examined. Activated caspase-3 immunoreactivity was detected in both neurons and astrocytes and was elevated in FTD cases as compared to control cases. A subset of activated caspase-3-positive cells were also TdT positive. In addition, the cell bodies of a subset of astrocytes showed enlarged, irregular shapes, and vacuolation and their processes appeared fragmented. These degenerating astrocytes were positive for activated caspase-3 and colocalized with robust TdT-labeled nuclei. These findings suggest that a subset of astrocytes exhibit degeneration and that DNA damage and activated caspase-3 may contribute to neuronal cell death and astrocyte degeneration in the FTD brain. Our results suggest that apoptosis may be a mechanism of neuronal cell death in FTD as well as in AD (228).

An error detection and recovery algorithm for compressed video signal using source level redundancy

The motion compensation-discrete cosine transform (MC-DCT) coding is an efficient compression technique for a digital video sequence. However, the compressed video signal is vulnerable to transmission errors over noisy channels. In this paper, we propose a robust video transmission algorithm, which protects the compressed video signal by inserting redundant information at the source level. The proposed algorithm encodes every lth frame in the semi-intra frame (S-frame) mode, in which the redundant parity-check DC coefficients (PDCs) are systematically inserted into the compressed bitstream. Then, the decoder is capable of recovering very severe transmission errors, such as loss of an entire frame, in addition to detecting the errors effectively without requesting any information from external devices. The proposed algorithm is implemented based on the H.263 coder, and tested intensively in realistic error prone environment. It is shown that the proposed algorithm provides much better objective and subjective performances than the conventional H.263 coder in the error prone environment.

Hybrid estimation of navigation parameters from aerial image sequence

This work presents a hybrid method for navigation parameter estimation using sequential aerial images, where navigation parameters represent the position and velocity information of an aircraft for autonomous navigation. The proposed hybrid system is composed of two parts: relative position estimation and absolute position estimation. Computer simulation with two different sets of real aerial image sequences shows the effectiveness of the proposed hybrid parameter estimation algorithm.

Cefazolin in chronic hemodialysis patients: a safe, effective alternative to vancomycin

Vancomycin use is common in hemodialysis patients, due in part to the ease of dosing, but can lead to the development of resistant organisms, including vancomycin-resistant enterococcus. Alternate antibiotics may be equally effective and allow similar dosing in the chronic hemodialysis population. A retrospective review of culture results from a 217-patient, non-hospital-based outpatient hemodialysis center was performed over a 7-month period. Wound and blood culture sensitivity to cefazolin, vancomycin, cefazolin plus gentamicin, and vancomycin plus gentamicin was analyzed. Cefazolin was equivalent to vancomycin for empiric treatment of clinically significant infections in a population with a low rate of methicillin-resistant Staphylococcus aureus infection. Cefazolin plus gentamicin was superior to vancomycin alone. The vancomycin plus gentamicin combination did provide minimally broader coverage than the cefazolin plus gentamicin combination. A prospective pharmacokinetic analysis of postdialysis cefazolin dosing was performed in anuric chronic hemodialysis patients dialyzed with polysulfone dialyzers. Peak, predialysis, and postdialysis cefazolin levels were obtained. Nondialysis clearance of cefazolin was sufficiently low (k(e), 0.027; t(1/2), 26.4 hours) and dialysis clearance sufficiently high (k(e), 0.254; t(1/2), 3.19 hours) to provide for safe and effective peak and trough cefazolin levels with postdialysis dosing in anuric hemodialysis patients. In conclusion, cefazolin alone or with gentamicin in an appropriate empiric antibiotic choice in chronic hemodialysis patients dialyzed in a nonhospital setting with low methicillin-resistant S. aureus infection rates. For infections with documented sensitivity to cefazolin, a 1 g intravenous dose postdialysis (750 mg in patients weighing <50 kg) is safe and effective.

Repin-induced neurotoxicity in rodents

Russian knapweed is a perennial weed found in many parts of the world, including southern California. Chronic ingestion of this plant by horses has been reported to cause equine nigropallidal encephalomalacia (ENE), which is associated with a movement disorder simulating Parkinson's disease (PD). Repin, a principal ingredient purified from Russian knapweed, is a sesquiterpene lactone containing an alpha-methylenebutyrolactone moiety and epoxides and is a highly reactive electrophile that can readily undergo conjugation with various biological nucleophiles, such as proteins, DNA, and glutathione (GSH). We show in this study that repin is highly toxic to C57BL/6J mice and Sprague-Dawley rats and acutely induces uncoordinated locomotion associated with postural tremors, hypothermia, and inability to respond to sonic and tactile stimuli. We also show that repin intoxication reduces striatal and hippocampal GSH and increases total striatal dopamine (DA) levels in mice. Striatal microdialysis in rats, however, has demonstrated a significant reduction of extracellular DA levels. These findings, coupled with the absence of any demonstrable change in striatal DOPAC levels, suggest that repin acts by inhibiting DA release, a hypothesis that is further supported by our demonstration that, in cultured PC12 cells, repin inhibits the release of DA without affecting its uptake. We believe, therefore, that inhibition of DA release represents one of the earliest pathogenetic events in ENE, leading eventually to striatal extracellular DA denervation, oxidative stress, and degeneration of nigrostriatal pathways. Since the neurotoxic effects of repin appear to be mediated via oxidative stress, and since repin is a natural product isolated from a plant in our environment that can cause a movement disorder associated with degeneration of nigrostriatal pathways, clarification of the mechanism of repin neurotoxicity may provide new insights into our understanding of the pathogenesis of PD.

Fractal coding of video sequence using circular prediction mapping and noncontractive interframe mapping

We propose a novel algorithm for fractal video sequence coding, based on the circular prediction mapping and the noncontractive interframe mapping. The proposed algorithm can effectively exploit the temporal correlation in real image sequences, since each range block is approximated by the domain block in the adjacent frame, which is of the same size as the range block. The computer simulation results demonstrate that the proposed algorithm provides very promising performance at low bit rate, ranging from 40-250 kbyte/s.

A fractal vector quantizer for image coding

We investigate the relation between VQ (vector quantization) and fractal image coding techniques, and propose a novel algorithm for still image coding, based on fractal vector quantization (FVQ). In FVQ, the source image is approximated coarsely by fixed basis blocks, and the codebook is self-trained from the coarsely approximated image, rather than from an outside training set or the source image itself. Therefore, FVQ is capable of eliminating the redundancy in the codebook without any side information, in addition to exploiting the self-similarity in real images effectively. The computer simulation results demonstrate that the proposed algorithm provides better peak signal-to-noise ratio (PSNR) performance than most other fractal-based coders.

Acute hemorrhagic leukoencephalitis during treatment for disseminated tuberculosis in a patient with AIDS

A 45-year-old man with the acquired immune deficiency syndrome (AIDS) developed disseminated Mycobacterium tuberculosis infection and was started on isoniazid, rifampin, pyrazinamide and ethambutol. The treatment was interrupted because of side effects. On resumption of treatment be developed a rapidly progressive neurological illness characterized by left hemiparesis, right gaze preference, convulsions, coma, evidence of cerebral edema on computed tomography scan and death 9 days later. Autopsy showed the presence of miliary tuberculosis affecting the lungs, liver, spleen, lymph nodes and bone marrow. The brain showed evidence of acute hemorrhagic leukoencephalitis (AHL)-the first such case in a patient with AIDS. We speculate that treatment-induced lysis of mycobacteria with concomitant release of mycobacterial lipoproteins may have activated T-lymphocytes to cause AHL in this patient.

Primary diffuse leptomeningeal gliomatosis with signs of increased intracranial pressure and progressive meningeal enhancement on MRI

A 21-year-old woman presented with a 5-month history of meningeal signs and evidence of intracranial hypertension and, as shown by magnetic resonance imaging (MRI), progressively more extensive meningeal enhancement, particularly within the spinal canal. Autopsy disclosed the presence of primary diffuse leptomeningeal gliomatosis with spinal cord predominance, possibly arising within heterotopic leptomeningeal glial tissue in the cervical region. No parenchymal primary lesion was identified. MRI with gadolinium appears to be the imaging modality of choice for the early detection of primary diffuse leptomeningeal neoplasia.

Decreases in protease nexins in Alzheimer's disease brain

A marked and significant reduction of protease nexin-1 (PN-1) and PN-2/amyloid beta protein precursor (A beta PP) was observed in selected regions of Alzheimer's disease (AD) brains as compared to those of aged-matched controls. Correlative analysis indicated a relationship between PN-1 reduction and the severity of pathologic alterations. A statistically significant inverse correlation was noted between the level of PN-1 activity and the density of tau-positive dystrophic neurites in the hippocampus. In view of the ability of thrombin and PN-1 activity to regulate neurite outgrowth, it is possible that abnormal thrombin and PN-1 interactions may play a role in dystrophic neurite formation. The presence of clusters of dystrophic neurites around the capillaries suggests that blood-brain barrier (BBB) dysfunction may enhance such abnormal interactions. The decrease in PN-2/A beta PP levels in AD brains could possibly contribute to neuronal degeneration in AD in view of the ability of PN-2/A beta PP to protect neurons against the toxic effects of the A beta.

Mycobacterium genavense infection presenting as a solitary brain mass in a patient with AIDS: case report and review

Patients with AIDS are prone to developing infections with opportunistic pathogens. Recently, a new mycobacterium, Mycobacterium genavense, has been found to cause infection in patients with AIDS. Previously published reports indicate that patients who are infected with this organism present with the same clinical features as do patients with disseminated infection due to organisms of the Mycobacterium avium complex. We describe an unusual case of a patient with AIDS who presented with grand mal seizures and a mass lesion in his brain, which was found to be caused by infection with M. genavense. No evidence of disseminated infection could be found in this patient. We discuss the microbiology of this organism and review the literature on M. genavense infections. Clinicians should be aware of this organism so that efforts at culture and identification will be made.

The development of cytomegalovirus encephalitis in AIDS patients receiving ganciclovir

PURPOSE

Cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS) requires lifelong therapy with either intravenous ganciclovir sodium or foscarnet sodium. From June 1989 through February 1992, seven patients with AIDS were diagnosed to have CMV retinitis, and all were treated with ganciclovir. Five of the seven developed abrupt preterminal mental status changes. All five with mental status changes received anti-CMV therapy until the time of death. Autopsies were performed in all cases to determine the cause of mental status changes.

PATIENTS AND METHODS

Five patients with AIDS and newly diagnosed CMV retinitis. Retrospective case analyses with autopsies. All five patients were treated with gangciclovir immediately upon the diagnosis of CMV retinitis and received ganciclovir at standard dosages until death.

RESULTS

Four patients had clinically stable retinitis throughout the entire course of ganciclovir therapy. In the fifth patient, because of fundoscopic deterioration, foscarnet therapy was initiated 1 month prior to death. Cerebrospinal fluid analysis and magnetic resonance imaging, although abnormal, were not diagnostically specific. Neuropathologic examination revealed fulminant diffuse CMV encephalitis in all patients, with prominent ependymal and periventricular necrosis.

CONCLUSIONS

These results suggest that while ganciclovir therapy may clinically stabilize CMV retinitis in patients with AIDS, it does not appear to prevent the development of, or be effective in the treatment of, CMV encephalitis. Thus, clinicians should consider the diagnosis of CMV encephalitis in patients receiving ganciclovir who develop mental status changes and, if possible, alter therapy accordingly.

Computerized quantitative radionuclide assessment of heterotopic ossification in spinal cord injury patients

We evaluated the progression of heterotopic ossification (HO) in 17 spinal cord injury patients by comparing radiographs, quantitative radionuclide bone scans, and serum alkaline phosphatase levels. Evidence of maturation of HO appeared earlier (3 months to 6 years post injury) in radiographs, whereas, during the same time frame, radioactive nuclide assessment showed continued progression of HO in 10 out of the 17 patients. The evolution of HO appeared to take place over a period ranging between 3 and 80 months. We believe that stabilization of HO may be reasonably defined in terms of uptake ratios of 2.0 or less in patients with initial uptake ratios over 3.0 but below 5.0, and of ratios of 3.0 or less when the initial values are over 5.0.

The ventriculus terminalis and filum terminale of the human spinal cord

Serial sections of the conus medullaris and the filum terminale of 23 randomly selected human spinal cords were studied by light and electron microscopy, and following immunoperoxidase staining for glial fibrillary acidic protein (GFAP), vimentin, neuron-specific enolase (NSE), amyloid beta protein, and S-100 protein. The intradural portion of the filum contains bundles of GFAP-positive glial fibers, scattered silver- and NSE-positive neurons, segments of peripheral nerve, blood vessels, fibrous connective tissue, and fat. Glial cell clusters varying from five to 100 cell layers thick at times constitute the bulk of the filum. The periependymal glial cells possess moderate amounts of eosinophilic cytoplasm and relatively uniform round to ovoid nuclei containing evenly distributed chromatin. They are distributed diffusely with no specific pattern of organization, although some of them showed a tendency to form acinar structures. A minority of the glial cells showed GFAP immunoreactivity, and some were immunoreactive for vimentin. Electron microscopy demonstrated the presence of periependymal cells showing cilia, microvilli, and the formation of intercellular junctional complexes, as well as cells containing bundles of glial filaments within the cytoplasm. Degenerated NSE-positive neurons and degenerated neurites resembling neuritic plaques were also demonstrated. However, immunoperoxidase staining for amyloid beta protein was negative in these structures. Thus, the filum terminale is endowed with an abundance of glial cells and neurons and is not simply a fibrovascular tag. Periependymal glial cells in the filum terminale should not be mistaken for neoplasm. The presence of neuropil with profuse astroglial and neuronal components within the filum terminale suggests a possible functional role for these structures.

Expression of protease nexin-II in human dorsal root ganglia. A correlative immunocytochemical and in situ hybridization study

Protease nexin-II (PN-II) is a potent chymotrypsin inhibitor that forms SDS-stable inhibitory complexes with epidermal growth factor binding protein, the gamma-subunit of nerve growth factor, and trypsin, and represents the secreted form of the amyloid beta-protein precursor (APP) that contains the Kunitz-type protease inhibitor domain. To determine the expression of PN-II within the peripheral nervous system, human dorsal root ganglia were processed for immunocytochemistry using well-characterized monoclonal antibodies against PN-II and for in situ hybridization studies using 35S-RNA PN-II probes for both APP751 and APP770. Highly specific immunoperoxidase staining of PN-II was demonstrated within the cytoplasm of dorsal root ganglia neurons and their processes in cryostat (fresh frozen) and vibratome (paraformaldehyde-fixed) sections. In situ hybridization using an anti-sense 35S-RNA PN-II probe demonstrated the presence of intense neuronal labeling. Labeling was not observed when the corresponding sense 35S-RNA PN-II probe was used. Although the precise functional role of PN-II/APP is not clear, the accumulation of amyloid beta-protein within the neuropil appears to be one of the earliest events in the pathogenesis of Alzheimer's disease (AD). Thus knowledge of the cell populations expressing the PN-II/APP gene would certainly be helpful for studies of the molecular mechanisms leading to the morphological and functional changes of AD. The results of this study clearly establish the expression of PN-II and its mRNA within the dorsal root ganglia neurons and their processes, and provide another point of departure for studies of the molecular mechanisms underlying the deposition of amyloid beta-protein and its relationships to the formation of neuritic plaques and neurofibrillary tangles.