Bielschowsky Silver Staining Research Articles

Delayed administration of a PTEN inhibitor BPV improves functional recovery after experimental stroke

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) inhibitors administered prior to or immediately after experimental stroke confer acute neuroprotection. However, it remains unclear if delayed treatment with a PTEN inhibitor improves long-term functional recovery after stroke. We addressed the issue in this study. Adult male mice were subjected to 1h of middle cerebral artery occlusion (MCAO) followed by treatment with a well-established PTEN inhibitor BPV or saline daily for 14days, starting at 24h after MCAO. Functional recovery was assessed with behavioral tests and acute infarct volumes were analyzed histologically. Delayed BPV treatment did not reduce infarction during the acute phase, but significantly improved long-term functional recovery after MCAO. Since PTEN is a critical intrinsic inhibitory factor in axonal regeneration, we further examined BPV effects on axonal densities following MCAO using bielschowsky silver staining and immunohistochemistry with antibodies against myelin basic protein. Delayed BPV treatment significantly increased axon densities in the ischemic brain at 14days after MCAO. Moreover, PTEN expression persistently remained high in the ischemic brain over 14days after MCAO, and BPV treatment increased post-ischemic activation of Akt and mTOR in the ischemic brain. Akt and mTOR activation are the well-established cascades downstream to PTEN inhibition and have been shown to contribute to post-injury axonal regrowth in response to PTEN inhibition. Consistently, in an in vitro neuronal ischemia model, BPV enhanced axonal outgrowth of primary cortical neurons after oxygen-glucose deprivation and the enhancing effects were abolished by Akt/mTOR inhibition. In conclusion, delayed BPV treatment improved functional recovery from experimental stroke possibly via enhancing axonal growth and Akt/mTOR activation contributed to BPV-enhanced post-stroke axon growth.

Secondary damage caused by CD11b+ microglia following diffuse axonal injury in rats

Diffuse axonal injury (DAI) is one of the most common and important pathologic features of human traumatic brain injury, accounting for high mortality and the development of persistent posttraumatic neurologic sequelae. Secondary damage resulting, e.g., from mass compressive effects through edema or inflammation can exacerbate morphologic changes in injured axons. In this study, DAI was induced in Sprague-Dawley rats by subjecting the animals to a midline closed-skull strike. Experimental rats and control animals subjected to sham operation were killed at 0 hour, 1 hour, 3 hour, 6 hour, 12 hour, 24 hour, 72 hour, 5 days, or 7 days later. Brains were harvested and paraffin-embedded sections of brain tissue (5 µm thick) were processed for hematoxylin and eosin staining, Bielschowsky silver staining, cresyl violet staining of Nissl bodies, Weil staining of myelin sheaths, or TUNEL assay to verify neuronal changes. Immunocytochemistry was used to examine the expression of [beta]-amyloid precursor protein, CD11b, and interleukin (IL)-6. CD11b/IL-6 expression was higher at 6 hour and peaked at 12 hour after injury. Pathologic changes in neurons were greater at 24 and 48 hour after injury. The results indicate that DAI can induce activation of microglia to express IL-6 in the early stages after injury. This suggests that microglia play an important role in secondary pathologic changes in brain tissue that are mediated, at least in part, by IL-6.

18F]Flutemetamol PET imaging and cortical biopsy histopathology for fibrillar amyloid β detection in living subjects with normal pressure hydrocephalus: pooled analysis of four studies

Molecular imaging techniques developed to 'visualize' amyloid in vivo represent a major achievement in Alzheimer's disease (AD) research. This pooled analysis of four studies determined the level of association between uptake of the fibrillar amyloid β positron emission tomography (PET) imaging agent [(18)F]flutemetamol (Pittsburgh Compound B analog with a 5.5 times longer half-life to enable it to be used in the clinical setting) and neuritic plaques and fibrillar amyloid β measured by pathologic staining of cortical region biopsy samples. Fifty-two patients with suspected normal pressure hydrocephalus underwent prospective (n=30) or retrospective (n=22) [(18)F]flutemetamol PET imaging for detection of cerebral cortical fibrillar amyloid β and cortical brain biopsy during intracranial pressure measurement or ventriculo-peritoneal shunting. [(18)F]Flutemetamol uptake was quantified using standardized uptake value ratio (SUVR) with cerebellar cortex as the reference region. Tissue fibrillar amyloid β was evaluated using immunohistochemical monoclonal antibody 4G8 and histochemical agents Thioflavin S and Bielschowsky silver stain, and an overall pathology result based on all available immunohistochemical and histochemical results. Biopsy site and contralateral [(18)F]flutemetamol SUVRs were significantly associated with neuritic plaque burden assessed with Bielschowsky silver stain (r (spearman's)=0.61, p=0.0001 for both), as was the composite SUVR with biopsy pathology (r (spearman's)=0.74, p<0.0001). SUVR and immunohistochemical results with 4G8 for detecting fibrillar amyloid β were similar. Blinded image evaluation showed strong agreement between readers (κ=0.86). Overall sensitivity and specificity by majority read were 93 and 100%. Noninvasive in vivo [(18)F]flutemetamol PET imaging demonstrates strong concordance with histopathology for brain fibrillar amyloid β, supporting its promise as a tool to assist physicians with earlier detection of the disease process and making diagnostic decisions about concomitant AD and other diseases associated with brain amyloidosis.

ATP7A Gene Addition to the Choroid Plexus Results in Long-term Rescue of the Lethal Copper Transport Defect in a Menkes Disease Mouse Model

Menkes disease is a lethal infantile neurodegenerative disorder of copper metabolism caused by mutations in a P-type ATPase, ATP7A. Currently available treatment (daily subcutaneous copper injections) is not entirely effective in the majority of affected individuals. The mottled-brindled (mo-br) mouse recapitulates the Menkes phenotype, including abnormal copper transport to the brain owing to mutation in the murine homolog, Atp7a, and dies by 14 days of age. We documented that mo-br mice on C57BL/6 background were not rescued by peripheral copper administration, and used this model to evaluate brain-directed therapies. Neonatal mo-br mice received lateral ventricle injections of either adeno-associated virus serotype 5 (AAV5) harboring a reduced-size human ATP7A (rsATP7A) complementary DNA (cDNA), copper chloride, or both. AAV5-rsATP7A showed selective transduction of choroid plexus epithelia and AAV5-rsATP7A plus copper combination treatment rescued mo-br mice; 86% survived to weaning (21 days), median survival increased to 43 days, 37% lived beyond 100 days, and 22% survived to the study end point (300 days). This synergistic treatment effect correlated with increased brain copper levels, enhanced activity of dopamine-β-hydroxylase, a copper-dependent enzyme, and correction of brain pathology. Our findings provide the first definitive evidence that gene therapy may have clinical utility in the treatment of Menkes disease.

Ante mortem amyloid imaging and β-amyloid pathology in a case with dementia with Lewy bodies

The association between ante mortem [11C]-Pittsburgh Compound B (PiB) retention and β-amyloid (Aβ) load, Lewy body (LB) and neurofibrillary tangle (NFT) densities were investigated in a pathologically confirmed case of dementia with Lewy bodies (DLB). A 76 year old man presenting with a clinical diagnosis of DLB had undergone PiB-positron emission tomography (PET), 18F FDG-PET and magnetic resonance imaging (MRI) 18 months before death. The pathologic diagnosis was DLB neocortical-type with low-likelihood of Alzheimer's disease by NIA-Reagan criteria. Sections from regions of interest (ROI) on post-mortem examination were studied. A significant correlation was found between cortical Aβ density and PiB retention in the 17 corresponding ROIs (r = 0.899; p < 0.0001). Bielschowsky silver stain revealed mostly sparse neocortical neuritic plaques, whereas diffuse plaques were frequent. There was no correlation between LB density and PiB retention (r = 0.13; p = 0.66); nor between NFT density and PiB retention (r = −0.36; p = 0.17). The ROI-based analysis of imaging and histopathological data confirms that PiB uptake on PET is a specific marker for Aβ density, but cannot differentiate neuritic from diffuse amyloid plaques in this case with DLB.

Axonal Pathology and Loss Precede Demyelination and Accompany Chronic Lesions in a Spontaneously Occurring Animal Model of Multiple Sclerosis

Axonal damage has been highlighted recently as a cause of neurological disability in various demyelinating diseases, including multiple sclerosis, either as a primary pathological change or secondary due to myelin loss. To characterize and quantify axonal damage and loss in canine distemper demyelinating leukoencephalomyelitis (DL), formalin-fixed paraffin-embedded cerebella were investigated histochemically and immunohistochemically using the modified Bielschowsky's silver stain as well as antibodies against nonphosphorylated (n-NF), phosphorylated neurofilament (p-NF) and beta-amyloid precursor protein (beta-APP). Injured axons characterized by immunoreactivity against n-NF and beta-APP were detected in early distemper lesions without demyelination. In subacute and chronic demyelinating lesions the number of injured axons increased. Moreover, a significant decrease in axonal density was observed within lesions and in the normal appearing white matter in DL as determined by morphometric analyses using Bielschowsky's silver stain and p-NF immunohistochemistry. Summarized, the observed findings indicate that axonal damage (i) occurs early in DL; (ii) can be detected before myelin loss; and (iii) represents a pivotal feature in advanced lesions. It must be postulated that axonal damage plays an important role in the initial phase as a primary event and during progression of nervous distemper as a result of demyelination.

Essential tremor with ubiquitinated Purkinje cell intranuclear inclusions

Essential tremor with ubiquitinated Purkinje cell intranuclear inclusions

P2-139: Homocysteine induces Alzheimer-like pathology and the possible mechanism in old rat

Epidemiological investigation and clinical data demonstrated there is significantly elevated plasma level of homocysteine in Alzheimer's disease (AD) patients. But AD-like pathology induced by hyperhomocysteinemia is unclear in old rats. Here we investigated the phosphoryaltion, solubility, the microtubule-binding capacity of tau, and the underlying mechanisms, as well as the memory impairment in old rats. Through vena caudalis injection for 6 months in 18-month-old rats, we employed Western blotting, immunohistochemistry, Bielschowsky's silver staining, biochemical fractionation and Morris water maze to measure the alterations of tau proteins and the spatial memory retention. We found that high plasma homocysteine induced tau hyperphosphorylation, which is mainly insoluble at Ser199/202, Ser-214, Ser-396, Ser-404 sites, led to the tau aggregates, decreased the microtubule-binding capacity of tau in the rat brain cortex, and resulted in the spatial impairment of the rats. Moreover homocysteine activated the glycogen synthase kinases-3β (GSK-3β) and inhibited the activity of protein phosphatase 2A (PP2A). A simultaneous supplement of folate and vitamin B12 restored partially the plasma homocysteine level and thus significantly antagonized the homocysteine-induced the hyperphosphorylation, insolubility, aggreagtes of tau, and restored the microtubule-binding ability of tau. and at the same time improved the spatial memory impairment, as well as GSK-3β activation and PP2A inactivation. Our results gave the first evidence in old rats that homocysteine may be an upstream effector to induce AD-like pathology through activating GSK-3β and inactivating PP2A.

Morphology and Innervation of the Human Cremaster Muscle in Relation to its Function

The electromyographic properties of the cremaster muscle (CM) are quite different from other skeletal muscles. It shows excessive spontaneous discharges, and the motor unit shape and firing frequency of the CM muscle differ from that of limb muscles. In this study, CM of six adult cadavers and six orchiectomy specimens were used to reveal the detailed histology of the muscle and provide an anatomophysiological explanation for these unusual electromyographic properties. Routine histochemical stains revealed the CM was composed of several distinct bundles of smooth and striated muscle fibers within connective tissue. The smooth muscle fibers that were more profuse than previously known and were not arranged in layers, but widely dispersed between striated muscle fibers. Bielschowsky silver staining technique, anti-neurofilament and anti-synaptophysin immunostaining showed the presence of multiple motor end-plates observed as a series of small dots or lines running along the striated muscle fibers and several nerve endings on a single muscle fiber. Myosin immunostaining confirmed the CM is a slow-twitch muscle, and alpha-actin smooth muscle immunostaining confirmed the presence of a large number of smooth muscle fibers. There were also small multipolar neurons forming nerve plexuses between smooth muscle fibers. Anti-GFAP immunostaining confirmed the presence of glial cells similar to astrocytes. In conclusion, the findings of this detailed anatomical study showed the CM, widely known as a striated muscle, contains a large number of smooth muscle fibers, and the spontaneous electromyographic discharges are due to the presence of multiple motor end-plates and dense innervation.

Intraventricular Enzyme Replacement Improves Disease Phenotypes in a Mouse Model of Late Infantile Neuronal Ceroid Lipofuscinosis

Late infantile neuronal ceroid lipofuscinosis (LINCL) is an autosomal recessive neurodegenerative disease caused by mutations in CLN2, which encodes the lysosomal protease tripeptidyl peptidase 1 (TPP1). LINCL is characterized clinically by progressive motor and cognitive decline, and premature death. Enzyme-replacement therapy (ERT) is currently available for lysosomal storage diseases affecting peripheral tissues, but has not been used in patients with central nervous system (CNS) involvement. Enzyme delivery through the cerebrospinal fluid is a potential alternative route to the CNS, but has not been studied for LINCL. In this study, we identified relevant neuropathological and behavioral hallmarks of disease in a mouse model of LINCL and correlated those findings with tissues from LINCL patients. Subsequently, we tested if intraventricular delivery of TPP1 to the LINCL mouse was efficacious. We found that infusion of recombinant human TPP1 through an intraventricular cannula led to enzyme distribution in several regions of the brain of treated mice. In vitro activity assays confirm increased TPP1 activity throughout the rostral-caudal extent of the brain. Importantly, treated mice showed attenuated neuropathology, and decreased resting tremor relative to vehicle-treated mice. This data demonstrates that intraventricular enzyme delivery to the CNS is feasible and may be of therapeutic value.

Evaluation of corticospinal axon loss by fluorescent dye tracing in mice with experimental autoimmune encephalomyelitis

In both multiple sclerosis (MS) patients and experimental autoimmune encephalomyelitis (EAE) animals, axon loss has been demonstrated to correlate with neurological disability. However, it is difficult to accurately determine the location and severity of axonal damage since the lesion in MS or EAE is disseminated and is frequently in a relapsing-remitting mode. The corticospinal system is the only direct pathway from the motorsensory cortex to the spinal cord, and the major neural pathway for control of voluntary movement. Moreover, it is frequently involved in the pathological process of the disease. To evaluate corticospinal tract (CST) axon loss in EAE mice, we developed a direct tracing method with a fluorescent neuronal tracer DiI which was injected into the primary motor cortex and sensorimotor cortex to label the pyramidal neurons. The lesion location in the spinal cord and axon disruption were indicated by dye leakage. Using the EAE induced axon reduction as an index of the extent of axonal damage, our data showed a high correlation between the axonal loss and the behavioral outcome score in the EAE mice. The results were consistent with the axonal Bielschowsky silver staining. Thus, this CST tracing method permits monitoring of the axonal damage in EAE.

Interlaboratory Comparison of Assessments of Alzheimer Disease-Related Lesions: A Study of the BrainNet Europe Consortium

This interlaboratory study evaluated the reproducibility of the assessments of neuritic plaques and neurofibrillary tangles (NFTs)--the hallmark lesions of Alzheimer disease--and compared the staining between the BrainNet Europe centers. To reduce the topography-related inconsistencies in assessments, we used a 2-mm tissue microarray (TMA) technique. The TMA block included 42 core samples taken from 21 paraffin blocks. The assessments were done on Bielschowsky and Gallyas silver stains using an immunohistochemical (IHC) method with antibodies directed to beta-amyloid (IHC/Abeta) and hyperphosphorylated tau (IHC/HPtau). The staining quality and the assessments differed between the participants, being most diverse with Bielschowsky (good/acceptable stain in 53% of centers) followed by Gallyas (good/acceptable stain in 57%) and IHC/Abeta (good/acceptable stain in 71%). The most uniform staining quality and assessment was obtained with the IHC/HPtau method (good/acceptable stain in 94% of centers). The neuropathologic diagnostic protocol (Consortium to Establish a Registry for Alzheimer Disease, Braak and Braak, and the National Institute of Aging and Reagan [NIA-Reagan] Institute) that was used significantly influenced the agreement, being highest with NIA-Reagan (54%) recommendations. This agreement was improved by visualization of NFTs using the IHC/HPtau method. Therefore, the IHC/HPtau methodology to visualize NFTs and neuropil threads should be considered as a method of choice in a future diagnostic protocol for Alzheimer disease.

P4-160: Cortical Lewy body disease is related to dementia and lower memory scores in older persons with and without Alzheimer’s disease pathology

Dementia with Lewy bodies is a common cause of dementia in older persons. Pathologically there is often coexisting Alzheimer's disease (AD). The relative contribution of Lewy body disease in persons with varying levels of AD pathology is not well understood. Investigate the contribution of cortical Lewy body disease to dementia and cognitive function in older persons with and without dementia. We studied 282 autopsied persons from the Religious Order Study, a longitudinal study of older Catholic clergy. The mean age at death was 85.6 years. Cognitive function was assessed about 7 months before death with 19 neuropsychologic tests which were used to create a global z–score and z–scores for episodic, semantic and working memory, perceptual speed and visual–spatial skills. The diagnosis of dementia was rendered by an experienced neurologist after review of all clinical data. We examined paraffin–embedded 6μm sections of frontal, temporal, parietal, cingulate, and entorhinal cortices, and substantia nigra, using alpha–synuclein immunostain (Zymed 1:100). Bielschowsky silver stain was used to count plaques and tangles in four cortical regions, and counts were summarized to create a global AD pathology measure. Macroscopic chronic cerebral infarctions were recorded. Analyses included Spearman Rank correlations and multiple logistic and linear regression controlling for age, sex, and education. 52 persons exhibited Lewy body disease (41 cortical type and 11 nigra predominant). Lewy bodies were not related to age (rho = 0.02, p=0.69) or AD pathology (rho = 0.03, p=0.63). After controlling for age, sex, education, AD pathology and infarctions, cortical Lewy body disease increased the odds of dementia by over 3 fold (OR=3.4, 95% CI=1.4–8.2), whereas nigra predominant disease was not associated with increased odds of dementia (OR=0.59, 95% CI=0.11–3.2). Cortical Lewy body disease was associated with lower episodic (parameter estimate = 0.81, p<0.001), semantic (parameter estimate = 0.73, p<0.01), and working memory (parameter estimate = 0.38, p=0.02) and lower perceptual speed (parameter estimate = 0.54, p<0.01). Cortical Lewy body disease increases the odds of dementia and is associated with lower memory function and processing speed in older persons, and this effect does not depend on the level of AD pathology.

The effect of social networks on the relation between Alzheimer's disease pathology and level of cognitive function in old people: a longitudinal cohort study

Few data are available about how social networks reduce the risk of cognitive impairment in old age. We aimed to measure this effect using data from a large, longitudinal, epidemiological clinicopathological study. 89 elderly people without known dementia participating in the Rush Memory and Aging Project underwent annual clinical evaluation. Brain autopsy was done at the time of death. Social network data were obtained by structured interview. Cognitive function tests were Z scored and averaged to yield a global and specific measure of cognitive function. Alzheimer's disease pathology was quantified as a global measure based on modified Bielschowsky silver stain. Amyloid load and the density of paired helical filament tau tangles were also quantified with antibody-specific immunostains. We used linear regression to examine the relation of disease pathology scores and social networks to level of cognitive function. Cognitive function was inversely related to all measures of disease pathology, indicating lower function at more severe levels of pathology. Social network size modified the association between pathology and cognitive function (parameter estimate 0.097, SE 0.039, p=0.016, R(2)=0.295). Even at more severe levels of global disease pathology, cognitive function remained higher for participants with larger network sizes. A similar modifying association was observed with tangles (parameter estimate 0.011, SE 0.003, p=0.001, R(2)=0.454). These modifying effects were most pronounced for semantic memory and working memory. Amyloid load did not modify the relation between pathology and network size. The results were unchanged after controlling for cognitive, physical, and social activities, depressive symptoms, or number of chronic diseases. These findings suggest that social networks modify the relation of some measures of Alzheimer's disease pathology to level of cognitive function.

Focally Elevated Creatine Detected in Amyloid Precursor Protein (APP) Transgenic Mice and Alzheimer Disease Brain Tissue

The creatine/phosphocreatine system, regulated by creatine kinase, plays an important role in maintaining energy balance in the brain. Energy metabolism and the function of creatine kinase are known to be affected in Alzheimer diseased brain and in cells exposed to the beta-amyloid peptide. We used infrared microspectroscopy to examine hippocampal, cortical, and caudal tissue from 21-89-week-old transgenic mice expressing doubly mutant (K670N/M671L and V717F) amyloid precursor protein and displaying robust pathology from an early age. Microcrystalline deposits of creatine, suggestive of perturbed energetic status, were detected by infrared microspectroscopy in all animals with advanced plaque pathology. Relatively large creatine deposits were also found in hippocampal sections from post-mortem Alzheimer diseased human brain, compared with hippocampus from non-demented brain. We therefore speculate that this molecule is a marker of the disease process.

Implicit memory and Alzheimer's disease neuropathology

Explicit memory failure is the defining cognitive feature of Alzheimer's disease and relates to the hallmark neuropathological features (plaques and tangles) of this illness. However, a pattern of preserved and impaired implicit memory has been found in Alzheimer's disease patients that may be explained by the association between the processing demands of certain implicit tests and the level of regional Alzheimer's disease neuropathology. In this study, we tested the hypothesis that these neuropathological features are related to implicit memory--measured by repetition priming--in a test that emphasized conceptual (or meaning-based) cognitive processing, and that the pathological changes are not related to implicit memory in a repetition priming test that emphasized perceptual (or sensory-based) cognitive processing. Subjects were older nuns, priests and brothers participating in the Religious Orders Study who agreed to annual neurological and neuropsychological evaluation for Alzheimer's disease and common neurological conditions of ageing, and brain autopsy at time of death. Explicit memory was measured by seven tests of episodic recall and recognition and converted to a previously established summary measure. Implicit memory was measured by four repetition priming tests. One test, category exemplar priming, emphasized conceptual, or meaning-based cognitive processing. A second test, word-identification priming, emphasized perceptual, or sensory-based cognitive processing. Two additional priming tests, picture-naming and word-stem completion, invoke both conceptual and perceptual processes. Neuritic and diffuse plaques, and neurofibrillary tangles identified by Bielschowsky silver stain, were quantified from five regions separately (frontal, parietal, temporal, entorhinal cortex and the hippocampus) and converted to a previously established summary measure. In linear regression analyses--controlling for age, sex and education--higher levels of Alzheimer's disease neuropathology were related to lower levels of explicit memory proximate to death. Higher levels of neuropathology were also related to lower levels of priming on the category-exemplar test, but were not related to levels of priming on the word-identification, picture-naming, or word-stem completion tests. The results suggest that hallmark indices of Alzheimer's disease neuropathology are associated with performance on priming tests to the extent that conceptual, but not perceptual, processing resources are required.

Mild cognitive impairment is related to Alzheimer disease pathology and cerebral infarctions

To examine the extent to which persons with mild cognitive impairment have intermediate levels of Alzheimer disease (AD) pathology, cerebral infarcts, and Lewy body disease. A total of 180 Catholic clergy participating in the Religious Orders Study underwent annual detailed evaluation and brain autopsy. Blocks of midfrontal, superior temporal, medial temporal lobe, inferior parietal, entorhinal cortex, hippocampus, and substantia nigra were paraffin embedded, and sectioned at 6 mum. Cortical neuritic plaques, diffuse plaques, and neurofibrillary tangles were visualized with Bielschowsky silver stain, and counted and summarized to yield a Braak stage, Consortium to Establish a Registry for Alzheimer's Disease (CERAD) diagnosis, National Institute on Aging (NIA)-Reagan diagnosis, and composite measure of AD pathology. The authors recorded the number and location of all gross chronic cerebral infarctions. Lewy bodies were identified with antibodies to alpha-synuclein. Multiple regression analyses were used to examine the relation of AD pathology and cerebral infarctions to clinical diagnosis proximate to death, controlling for age, sex, and education. A total of 37 had mild cognitive impairment, 60 did not have cognitive impairment, and 83 had dementia proximate to death. Nearly all persons had at least some AD pathology. Cerebral infarctions were present in 35.2%, and 15.6% had Lewy body disease. Persons with mild cognitive impairment were intermediate in terms of Braak stage and CERAD and NIA-Reagan neuropathologic criteria for AD compared to the other two groups. In multiple regression analyses, persons with mild cognitive impairment had intermediate levels of AD pathology from those without cognitive impairment and those with dementia (test for trend, F = 45.2, p < 0.001). Further, the relation between cognition and AD pathology in persons with mild cognitive impairment did not differ significantly from the relation between cognition and AD pathology in persons with dementia or those without cognitive impairment. Persons with mild cognitive impairment also had intermediate levels of cerebral infarctions (test for trend, p = 0.04). Only 3 (8.1%) persons with mild cognitive impairment had Lewy body disease. These data suggest that mild cognitive impairment may be the earliest clinical manifestation of common age-related neurologic diseases.

Transgenic mice overexpressing amyloid beta protein are an incomplete model of Alzheimer disease

We compared lesions in elderly transgenic (tg) mice carrying the Swedish double mutation KM670/671NL with lesions in Alzheimer disease (AD) by histochemical and immunohistochemical techniques. Highly similar staining for beta-amyloid protein (Aβ) was observed in AD and the mouse models. The abundant amyloid deposits in tg mice were in a consolidated state as revealed by strong Congo red birefringence. In both tg mice and AD, amyloid deposits were ApoE-positive and were surrounded by activated astrocytes. However, Bielschowsky silver staining and immunostaining with tau antibodies revealed no neurofibrillary tangles (NFTs) in the mice as opposed to abundant NFTs in AD. The microglial pattern was also distinctly different. Tg mice had only weakly activated microglia, which expressed low levels of the complement receptor CD11b. They were gathered around the periphery of the deposits. In contrast, AD lesions had strongly activated microglia, which expressed high levels of CD11b. They were associated with the plaque core. Immunostaining for complement proteins was weak in tg mice but very strong in AD deposits. We conclude that the weak inflammatory response and absence of NFTs indicate that tg mice are only a limited model of AD. Therapeutic strategies for the treatment of AD based on tg mouse models that overexpress Aβ may be limited in their application.

CSF Abeta 42 levels correlate with amyloid-neuropathology in a population-based autopsy study.

To investigate the relationship of amyloid neuropathology to postmortem CSF Abeta 42 levels in an autopsy sample of Japanese American men from the population-based Honolulu-Asia Aging Study. In 1991, participants were assessed and diagnosed with dementia (including subtype) based on published criteria. At death CSF was obtained from the ventricles. Neuritic plaques (NP) and diffuse plaques in areas of the neocortex and hippocampus were examined using Bielschowsky silver stains. Cerebral amyloid angiopathy (CAA) was measured by immunostaining for beta4 amyloid in cerebral vessels in the neocortex. Neuropathologically confirmed AD was diagnosed using Consortium to Establish a Registry for Alzheimer's Disease criteria. In 155 autopsy samples, log transformed linear regression models were used to examine the association of NP and CAA to Abeta 42 levels, controlling for clinical dementia severity, time between diagnosis and death, age at death, brain weight, hours between death and collection of CSF, education, and APOE genotype. Higher numbers of NP in the neocortex (p trend = 0.001) and in the hippocampus (p trend = 0.03) were strongly associated with lower levels of Abeta 42. Individuals with CAA had lower Abeta 42 levels (beta coefficient = -0.48; 95% CI -0.9, -0.1). Compared to participants with a diagnosis of clinical dementia, those with pathologically confirmed AD had lower Abeta 42 levels (beta coefficient = -0.74; 95% CI -1.4, -0.1). The current study suggests that lower Abeta 42 levels reflect neuropathologic processes implicated in amyloid-related pathologies, such as NP and CAA.

An Evaluation of Three Conventional Histological Techniques for Staining the Cerata of Cratena pilata

Fixation and staining methods for different types of tissue in the marine nudibranch Cratena pilata were evaluated. Cratena pilata, a marine snail in the Phylum Mollusca, has the ability to take stinging cells, called nematocysts, from ingested animals belonging to another phylum, the coelenterates, and use them for their own defense. A total of I0 nudibranchs were used; 6 were preserved in 10% formalin and 4 in Helly's fixative. Three different types of stains were compared: hematoxylin and eosin (H&E), Cason's modified trichrome stain, and Bielschowsky's silver stain. The animals fixed in Helly's fixative were stained with Cason's modified trichrome stain and H&E. The formalin fixed animals were stained with either Cason's modified trichrolne stain or Bielschowsky's silver stain. Helly's fixative in conjunction with H&E proved to be the best combination to examine the general morphology of Cratena pilata. Cason's modified trichrome stain was the best stain for differentiating gut tissue, muscle, basement membrane, nematocysts, and the cerebral ganglion. Although Bielschowsky's silver stain stained nerves, Cason's modified trichrome stain proved to be the better stain to differentiate neuronal axons and cell bodies. (The J Histotechnol 24:255, 2001)Submitted: February 2, 2001; Accepted: April 6, 2001