SAMP8 mice as a neuropathological model of accelerated brain aging and dementia: Toshio Takeda's legacy and future directions.

Senescence accelerated mice P8 (SAMP8) show significant age-related deteriorations in memory and learning ability in accordance with early onset and rapid advancement of senescence. Brains of SAMP8 mice reveal an age-associated increase of PAS-positive granular structures in the hippocampal formation and astrogliosis in the brain stem and hippocampus. A spongy degeneration in the brain stem appears at 1 month of age and reaches a maximum at 4-8 months. In addition, clusters of activated microglia also appear around the vacuoles in the brain stem. ß/A4(Aß) protein-like immunoreactive granular structures are observed in various regions and increase in number markedly with age. Other age-associated histological changes include cortical atrophy, neuronal cell loss in locus coeruleus and lateral tegmental nuclei, intraneuronal accumulation of lipopigments in Purkinje cells and eosinophilic inclusion bodies in thalamic neurons. A blood-brain barrier dysfunction and astrogliosis are also prominent with advancing age in the hippocampus. These changes are generally similar to the pathomorphology of aging human brains and characterized by their association with some specific glioneuronal reactions. As for the hallmarks of Alzheimer brains, tau morphology has not yet been confirmed regardless of the age-related increase in phosphorylated tau in SAMP8 mice brains, but early age-related Aß deposition in the hippocampus has recently been published. SAMP8 mice are, therefore, not only a senescence-accelerated model but also a promising model for Alzheimer's disease and other cognitive disorders.

High Morning and Bedtime Home Blood Pressures Strongly Predict for Post-Stroke Cognitive Impairment.

BACKGROUND: Hypertension may be the most modifiable risk factor for post-stroke cognitive impairment (PSCI). We investigated how home blood pressure (HBP) can predict PSCI as well as stroke recurrence. METHODS: We studied 249 consecutive patients with noncardioembolic minor ischemic stroke including single lacunar infarct (sLI), multiple lacunae (mLI), and atherothrombotic infarction, which were tracked at our outpatient clinic. HBP was measured in the early morning (m-HBP) and just before going to bed (b-HBP). HBP categories based on systolic blood pressure were created as follows: HB1, both m-HBP and b-HBP less than 135 (mmHg); HB2, m-HBP less than or equal to135 and b-HBP less than 135; HB3, m-HBP less than 135 and b-HBP less than or equal to 135; HB4, both m-HBP and b-HBP less than or equal to 135. After 4.1 years of tracking, the patients were divided into 4 groups: Group 1, good outcome (n = 188); Group 2, the development of silent infarcts (n = 16); Group 3, the development of PSCI (n = 33); and Group 4, stroke recurrence (n = 15). RESULTS: HB2 and HB4 (versus HB1) (hazard ratio [HR]: 6.5, P = .0068 and HR: 9.5, P = .0008, respectively) and mLI (versus sLI) (HR: 4.0, P = .021) were independently associated with Group 2. HB3 and HB4 (HR: 4.2, P = .037; HR: 5.4, P < .0001) and mLI (HR: 6.4, P < .0001) were significantly associated with Group 3. HB4 (HR: 8.1, P = .0002) and mLI (HR: 10.2, P = .0003) were significantly associated with Group 4. Clinic blood pressure (BP) was not significantly associated with any adverse groups. CONCLUSIONS: High HBP and mLI were strongly associated with PSCI as well as stroke recurrence. BP should be monitored based on HBP, especially bedtime HBP, for the prevention of PSCI.

Hippocampal metabolites and memory performances in patients with amnestic mild cognitive impairment and Alzheimer's disease.

In patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD), previous studies have reported the decrease of N-acetylaspartate (NAA) concentration and the increase of myo-inositol (MI) concentration using proton magnetic resonance spectroscopy (1H-MRS). However, it remains to be investigated what aspects of cognition these metabolite changes reflect. In this study we evaluated the correlations between the subtests of Wechsler Memory Scale-Revised (WMS-R) and the concentrations of NAA and MI. The study group was composed of 42 patients with aMCI and 67 patients with AD. 1H-MR spectra with a single voxel-point resolved spectroscopy (PRESS) at a short echo time were acquired from the bilateral hippocampi and posterior cingulate gyrus. Positive correlations were shown between the NAA concentration in the left hippocampus and verbal memory, visual memory, general memory, attention and delayed recall; and furthermore, between the NAA concentration in the right hippocampus and verbal memory and general memory. Negative correlations were shown between the MI concentration in the left hippocampus and verbal memory, general memory, and delayed recall, and between the MI concentration in the right hippocampus and verbal memory. There was no significant correlation between any subtest of WMS-R and these two metabolite concentrations in the posterior cingulate gyrus. These findings suggest that bilateral, especially left hippocampal NAA and MI concentrations are associated with memory dysfunction observed in patients with aMCI and AD. In contrast, NAA and MI concentrations in the posterior cingulate gyrus may be less related to memory function than those in the hippocampus.

Posterior reversible encephalopathy syndrome presenting with thrombotic microangiopathy triggered by malignant hypertension: a case report and literature review.

Background: Posterior reversible encephalopathy syndrome (PRES) is a disease characterised by reversible subcortical vasogenic oedema, neurological symptoms and abnormal findings on head imaging. It is recognised as one of the most prominent organ disorders in hypertensive emergencies but is rarely associated with thrombotic microangiopathy (TMA). Case presentation: A woman in her 40s with untreated hypertension had occasional headaches in the past 4 months. The headaches worsened during the 3 weeks prior to admission. On the day of admission, the patient presented with severe headache accompanied by frequent vomiting. MRI of the head revealed oedematous changes in the brainstem, including the subcortical, cerebellum and pons. Fundus examination revealed hypertensive retinopathy with papilloedema. Blood tests indicated thrombocytopenia, renal dysfunction and haemolytic anaemia, and a blood smear confirmed fragmented erythrocytes. Coombs' test, and tests for ADAMTS13 activity and infectious and autoimmune diseases were negative. The patient was diagnosed with PRES, secondary to malignant hypertension (MH) and associated with TMA. Antihypertensive therapy promptly improved the clinical symptoms, blood pressure, and the abnormal MRI and blood test findings. The patient was discharged from the hospital 20 days after admission. Conclusions: We report a rare case of PRES that was associated with TMA and triggered by MH. Antihypertensive therapy was effective in alleviating the associated adverse clinical symptoms. Differentiation of underlying diseases is essential for early intervention, since treatment depends on factors causing TMA.

Soluble TREM2 and Alzheimer-related biomarker trajectories in the blood of patients with diabetes based on their cognitive status.

AIM: We aimed to elucidate the dynamics of blood biomarkers according to the severity of cognitive impairment in patients with type 2 diabetes mellitus (DM) and to identify useful biomarkers for diabetes-related dementia. METHODS: This was a cross-sectional, nested case-control study of 121 Japanese DM and non-DM patients with different levels of cognitive functioning. We evaluated participants' cognitive functions, blood biomarkers related to Alzheimer's disease, and soluble triggering receptors expressed on myeloid cells 2 (sTREM2). We then compared these biomarkers between the DM and non-DM and across the different cognitive strata. RESULTS: In all cognitive strata, significantly lower levels of serum sTREM2 were observed in the DM than in the non-DM. We also found that plasma levels of phosphorylated tau (p-tau) increased with increasing levels of cognitive decline in both the DM and non-DM. However, this was accompanied by a decrease in plasma amyloid-ß(Aß42/Aß40 ratios in non-DM only. CONCLUSION: This study revealed novel characteristic trajectories of dementia-related blood biomarkers in diabetes-related dementia, suggesting the pathological involvement of molecular cascades initiated by impaired microglial activation. This results in decreased serum sTREM2, followed by tauopathy without substantial amyloid plaques, reflected by plasma p-tau elevation with no decrease in the Aß42/Aß40 ratio. Clinical trials (the unique trial number and the name of the registry): UMIN000048032, https://www.umin.ac.jp.

The association of disproportionately enlarged subarachnoid space hydrocephalus with cognitive deficit in a general population: the Ohasama study.

Disproportionately enlarged subarachnoid space hydrocephalus (DESH) is the characteristic feature of idiopathic normal pressure hydrocephalus. We aimed to characterize the prevalence, development, and association of DESH to cognitive deficit in a large population. We reviewed the data of 1384 subjects eligible for the present study among 1590 participants who underwent magnetic resonance imaging (MRI) in the Ohasama Study, a population-based study in Ohasama, Japan. The participants with Mini-Mental State Examination (MMSE) score < = 25 were assumed to have cognitive deficit and DESH was evaluated by reviewing the MRIs. We assessed the association between DESH, Evans index (EI), and cognitive deficit using multivariate logistic regression models adjusted for relevant confounders. Furthermore, we evaluated the new development of DESH and the deterioration of cognitive function in the participants with DESH. There were nine participants with DESH (0.65%), seven of whom showed cognitive deficit. DESH was significantly associated with cognitive deficit in multivariate regression analyses (odds ratio; 8.50 [95% confidence interval: 1.61-44.88]). In the 669 participants who underwent follow-up MRI, we found four participants newly presenting with DESH; the development of DESH was observed before/after the presence of EI > 0.3. We also found two participants with existing DESH showing no remarkable worsening in MMSE and EI. The present study demonstrated a positive association between the presence of DESH and cognitive deficit. DESH can develop independently of EI > 0.3, and ventricular enlargement in combination with DESH may be an important factor in the worsening of cognitive deficit.

Absolute quantification in proton magnetic resonance spectroscopy is useful to differentiate amnesic mild cognitive impairment from Alzheimer's disease and healthy aging.

BACKGROUND/AIMS: Amnesic mild cognitive impairment (aMCI) is thought to represent a transitional state between healthy aging and very mild Alzheimer's disease (AD). It is very important to diagnose aMCI for early treatment. In order to investigate biochemical changes in aMCI, we measured metabolite concentrations using proton magnetic resonance spectroscopy ((1)H-MRS) from patients with aMCI and compared the results with healthy controls (HCs) and patients with AD. METHODS: The subjects were 52 HCs, 70 AD patients and 47 aMCI patients. (1)H-MR spectra with single-voxel point-resolved spectroscopy at a short echo time (TE) were acquired from 8 volumes of interest in the brain. RESULTS: The bilateral hippocampal N-acetylaspartate (NAA) concentrations from aMCI patients showed intermediate values, which were lower than those from HC subjects but higher than those from AD patients. The patients with aMCI also had lower concentrations of NAA than HCs in the bilateral posterior periventricular and deep white matters (PDWM) and posterior cingulate gyrus and had lower levels of choline compounds in the left posterior PDWM. CONCLUSION: Using a single-voxel (1)H-MRS at a short TE, we revealed that absolute quantification is useful to detect the characteristic patterns of metabolite concentrations in patients with aMCI as compared with AD patients and HCs.

Accumulation of HtrA2/Omi in neuronal and glial inclusions in brains with alpha-synucleinopathies.

HtrA2/Omi is a mitochondrial serine protease that is released into the cytosol and promotes apoptotic processes by binding to several members of the inhibitors of apoptosis protein family. HtrA2/Omi knockout mice show a parkinsonian phenotype, and mutations in the gene encoding HtrA2/Omi have been identified as susceptibility factors for Parkinson disease (PD). These results suggest that HtrA2/Omi may be involved in the pathogenesis of PD. We performed immunohistochemical studies of HtrA2/Omi on brains from patients with alpha-synuclein-related disorders, including PD, dementia with Lewy bodies (DLB), and multiple-system atrophy (MSA); patients with other neurodegenerative diseases; and controls. HtrA2/Omi is expressed in normal brain tissue, and there was some anti-HtrA2/Omi immunostaining of neurons in normal brains as well as those with other neurodegenerative diseases. In PD and DLB brains, both classic (i.e. brainstem-type) and cortical Lewy bodies were intensely immunostained; pale bodies were also strongly immunopositive for HtrA2/Omi. In MSA brains, numerous glial cytoplasmic inclusions, neuronal cytoplasmic inclusions, and dystrophic neurites were also intensely immunoreactive for HtrA2/Omi. These results suggest that widespread accumulation of HtrA2/Omi may occur in pathologic alpha-synuclein-containing inclusions in brains with PD, DLB, or MSA and that HtrA2/Omi may be associated with the pathogenesis of alpha-synucleinopathies.

Shunt-responsive parkinsonism and reversible white matter lesions in patients with idiopathic NPH.

BACKGROUND: Idiopathic normal pressure hydrocephalus (iNPH) is a potentially treatable dementia and gait disorder with abnormal CSF dynamics. OBJECTIVE: To investigate and characterize the changes in motor symptoms and CT and MRI features of iNPH before and after a shunt operation using specific evaluation criteria. METHODS: We studied 17 definitive iNPH patients, diagnosed according to the clinical guidelines of both the Japanese Society of NPH and the International NPH Consultant Group, with ventricular enlargement (Evan's index > 0.3) and narrowed CSF spaces at the high convexity on CT scan and /or MRI. The pre- and post-operative evaluation criteria for the gait and motor disturbances included the Japanese NPH Grading Scale-Revised (JNPHGSR), the Timed "Up and Go" test and the motor sections of the Unified Parkinson Disease Rating Scale. For cognitive impairments, the JNPHGSR, Mini Mental State Examination, Frontal Assessment Battery and Trail Making Test were used. White matter lesions were rated from the CT and/or MRI using a validated visual rating scale. RESULTS: All patients showed specific CT and MRI findings, consisting of diffusely-dilated Sylvian fissure, as well as narrowed CSF space at the high convexity. Fifteen patients (88%) showed white matter lesions on their CT or MRI images. These signs were ameliorated in all patients after the shunt operation. Evan's index and the mean total scores on the visual scale for white matter lesions also improved significantly. Clinically, the patients had frequent parkinsonism (71%), but relatively few had a history of either small-vessel diseases (29%), hypertension (41%) or diabetes (35%). All patients showed gait disturbances, and these symptoms, including postural instability and body bradykinesia, improved significantly after the operation. Over half also showed signs of cognitive impairment and urinary incontinence, and all such symptoms and signs improved significantly. CONCLUSION: iNPH often appears as a shunt-responsive type of parkinsonism and reversible white matter lesions among the geriatric population.

Absolute quantification in proton magnetic resonance spectroscopy is superior to relative ratio to discriminate Alzheimer's disease from Binswanger's disease.

BACKGROUND/AIMS: Although many proton magnetic resonance spectroscopy studies have assessed the relative ratios of brain metabolites from patients with dementia, absolute quantification is rare. The aim of this study is to compare the diagnostic accuracy of these 2 methods in proton magnetic resonance spectroscopy in discriminating Alzheimer's disease (AD) and Binswanger's disease (BD) from healthy controls (HC). METHODS: The subjects were 30 AD patients, 13 BD patients and 26 HC subjects. Single-voxel proton MR spectra at short echo times were acquired from 8 volumes of interest. RESULTS: At 80% specificity, the absolute N-acetylaspartate concentration in the hippocampus was the most sensitive measure to discriminate AD from HC, and the absolute N-acetylaspartate concentration in the anterior periventricular and deep white matter to differentiate BD from HC and AD. No relative ratio using creatine as a reference had a sensitivity over 80% at 80% specificity. The cause of disparities between the 2 methods was attributed to fluctuations in the creatine concentration. CONCLUSION: Our study revealed that absolute quantification is superior to relative ratio to differentiate AD and BD from HC.

Different atrophic patterns in early- and late-onset Alzheimer's disease and evaluation of clinical utility of a method of regional z-score analysis using voxel-based morphometry.

BACKGROUND/AIMS: We evaluated the differential patterns of brain atrophy in early- and late-onset Alzheimer's disease (AD) by measuring regional z-scores of voxel-based morphometry and assessed the availability of the method for clinical use. METHODS: The first 50 patients with probable AD were compared to 83 age-matched control subjects to identify the brain atrophy. Regions of interest were set in the areas showing z-scores >4. To find substantial differences in the atrophy pattern, principal component analysis was performed. The second group of 56 patients with memory complaints entered the study for evaluation of the clinical use of the model. RESULTS: The centers of the regions of interest were the amygdala, anterior hippocampi, posterior hippocampi, temporal cortices and subcallosal cortex, and left posterior cingulate cortex (PCC). Eigenvectors of the temporal cortices and left PCC showed counter-directions to those of patient age, suggesting that patients with younger onset age were preferentially associated with atrophy of those regions. Differential analyses of the second group showed high availability for the detection of abnormal brain atrophy in people with subjective memory complaints. CONCLUSION: AD with earlier onset is preferentially related to PCC and temporal lobe atrophy. Voxel-based morphometry can be statistically analyzed, and this method has the potential for bias-free assessment of brain atrophy.

A computer support system for neurological anatomical diagnosis.

OBJECTIVES: Accurate neurological diagnoses are often difficult to make due to the complexity of the neuroanatomy involved. This study was performed to evaluate the usefulness of a computer system with easily retrievable anatomical information as a support for arriving at more accurate anatomic diagnoses. PATIENTS AND METHODS: Anatomical information from an initial physical examination was programmed into a computer with stored neuroanatomical charts of the brain, spinal cord and peripheral nerves. The information generated a graphic display of possible lesions with suggestions for further examination. These suggestions were then followed and further data entered. This data entry generated a new graphic display with reduced lesion possibilities. Iterations were then followed to narrow the possibilities for diagnosis further, until a final anatomical diagnosis was reached. This method was applied to three hypothetical examples and a number of clinical cases. Here we report three clinical cases in which this method was particularly useful in making a diagnosis. RESULTS: Using computer iterations, the system was able to pinpoint one or more presumptive causative lesions in the CNS or PNS based on known neuronal pathways or nuclei. CONCLUSION: The results indicate that suitably used, computer memory, by virtue of its large capacity, accuracy and fast recall, can supplement human memory in reaching accurate anatomical diagnoses of neurological lesions.

Two cases of sporadic adult-onset neuronal intranuclear inclusion disease preceded by urinary disturbance for many years.

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease defined by the presence of eosinophilic hyaline intranuclear inclusions. The initial and main clinical feature of adult-onset NIID is predominantly dementia. We present herein 2 cases of sporadic adult-onset NIID with longstanding urinary disturbance prior to development of other neurological symptoms. Case 1: A 71-year-old woman was admitted after she lost consciousness while bathing. She presented slowly progressive bladder dysfunction starting at the age of 40. Recently, she complained of recurrent light-headedness on standing. Her neurological findings showed miosis, muscle weakness, rigidity, hyporeflexia, sensory disturbance, cerebellar ataxia, and orthostatic hypotension. Case 2: A 68-year-old man was admitted because of episodes of transient loss of consciousness. Ten years earlier, he had developed urinary dysfunction. His neurological findings revealed cognitive dysfunction, cerebellar ataxia, and hyporeflexia. Both patients had leukoencephalopathy and motor-sensory neuropathy. In both cases, diffusion-weighted imaging showed high-intensity signals in the corticomedurally junction; and skin biopsy samples revealed ubiquitin-positive intranuclear inclusions. Therefore, we made a diagnosis of adult-onset NIID. Although numerous cases of this disorder have been reported in the past, there were only a few cases showing the development of other neurological symptoms after longstanding urinary disturbance. Our cases suggest that it is worthwhile considering the possibility of NIID in cases with a long-term history of neurogenic bladder dysfunction.

Accumulation of triosephosphate isomerase, with sequence homology to Beta amyloid peptides, in vessel walls of the newborn piglet hippocampus.

We investigated whether beta-amyloid (Abeta)-like immunoreactivity was seen in the brains of newborn piglets. The immunoreactivity for Abeta(1-42) and Abeta(1-40) proteins, but not Abeta precursor protein, was present in CD68-positive perivascular cells of the hippocampus and in parts of the meninges. It was colocalized with immunoreactivity for receptor for advanced glycation end product and tumor necrosis factor-alpha. The protein with a molecular mass of 27 kDa, which was recognized by the Abeta antibodies, was identified as triosephosphate isomerase (TPI) with sequence homology to Abeta peptides by N-terminal amino acid sequencing, mass fingerprint analysis using matrix-associated laser desorption/ionization mass spectrometry, and Western blotting. Western blotting assay also revealed that detectable expression of Abeta proteins were not seen in the piglet brains. These findings indicate that TPI with sequence homology to Abeta peptides accumulates in perivascular cells of the microglia/macrophage lineage located around arterial vessels of the newborn piglet hippocampus.

Accumulation of Hsc70 and Hsp70 in glial cytoplasmic inclusions in patients with multiple system atrophy.

Heat shock proteins (HSPs) are molecular chaperones which can be induced by several kinds of stresses, and Hsc70 and Hsp70 are two major members of the family of 70 kDa HSPs. A major component of Lewy bodies (LBs) is alpha-synuclein, and Hsp70 has been observed in the LBs of brains with Parkinson's disease. Hsp70 has also been demonstrated to have the ability to suppress alpha-synuclein toxicity in vitro and in vivo. To investigate the precise role of Hsc70 and Hsp70 in patients with multiple system atrophy (MSA), which is another alpha-synuclein-related disease, we performed immunohistochemical studies on Hsc70 and Hsp70 using autopsied brains from 7 normal subjects and 15 patients with MSA. In the normal human brains, both neurons and glial cells, including oligodendrocytes, showed only weak Hsc70 and Hsp70 immunoreactivities. In contrast, in the brains with MSA, numerous glial cytoplasmic inclusions (GCIs) were intensely immunostained with Hsc70, and strong Hsc70 immunoreactivity was also found in glial intranuclear inclusions (GNIs), neuronal cytoplasmic inclusions (NCIs) and neuronal intranuclear inclusions (NNIs) as well as dystrophic neurites. The immunolabeling pattern for Hsp70 in the MSA brains was slightly different from that of Hsc70, and Hsp70 immunoreactivity was observed in many reactive astrocytes as well as some glial and neuronal inclusions. Our results suggest that the widespread accumulation of Hsc70 and Hsp70 may occur in brains with MSA, and that Hsc70 and Hsp70 may be associated with the pathogenesis of MSA.

The relationship between progressive motor deficits and lesion location in patients with single infarction in the lenticulostriate artery territory.

As the corticospinal tracts cross the lenticulostriate artery (LSA) territory at the posterior segment, we hypothesized that posteriorly located infarctions of the LSA may be associated with progressive motor deficits. We prospectively studied 519 consecutive patients with LSA infarctions who entered our hospital within 24 h after onset. We categorized patients into two groups in terms of progress: no progress and progress. Progress was defined as worsening by 1 point or more in the National Institutes of Health Stroke Scale (NIHSS), some of which recovered afterward or thoroughly progressed. LSA infarctions on the first DWI were divided into proximal type and distal (group 1) type. The proximal type was further divided into anterior (group 2), intermediate (group 3) and posterior (group 4) type according to the middle point of antero-posterior diameter of the lateral ventricle. There were 109 patients who showed progress that accounted for 21.0% of all patients. The number of patients who progressed is as follows: distal type 65 (23.8%), anterior type 31 (36.0%), intermediate type 26 (56.5%) and posterior type 97 (85.0%). The Cochran-Armitage test showed a significant increase through group 1 to group 4 (p < 0.0001). Independent predictive factors for progress were male (OR 0.57, p = 0.0107), higher NIHSS on admission (≥4) (OR 3.02, p < 0.0001), intermediate proximal type (OR 3.3, p = 0.0007) and posterior proximal type (OR 16.4, p < 0.0001). The more posterior the infarct location, the more frequent was the progress that occurred, probably due to the anatomical fact that corticospinal tracts crossed the LSA territory at the posterosuperior quadrant.

Sex-related difference in human white matter volumes studied: Inspection of the corpus callosum and other white matter by VBM.

It has been contended that any observed difference of the corpus callosum (CC) size between men and women is not sex-related but brain-size-related. A recent report, however, showed that the midsagittal CC area was significantly larger in women in 37 brain-size-matched pairs of normal young adults. Since this constituted strong evidence of sexual dimorphism and was obtained from publicly available data in OASIS, we examined volume differences within the CC and in other white matter using voxel-based morphometry (VBM). We created a three-dimensional region of interest of the CC and measured its volume. The VBM statistics were analyzed by permutation test and threshold-free cluster enhancement (TFCE) with the significance levels at FWER < 0.05. The CC volume was significantly larger in women in the same 37 brain-size-matched pairs. We found that the CC genu was the subregion showing the most significant sex-related difference. We also found that white matter in the bilateral anterior frontal regions and the left lateral white matter near to Broca's area were larger in women, whereas there were no significant larger regions in men. Since we used brain-size-matched subjects, our results gave strong volumetric evidence of localized sexual dimorphism of white matter.

Upregulated expression of 14-3-3 proteins in astrocytes from human cerebrovascular ischemic lesions.

BACKGROUND AND PURPOSE: Several types of chaperone proteins, such as heat shock proteins, have been reported to be associated with brain ischemia. The purpose of this study was to investigate whether an abnormal expression of 14-3-3 proteins, a novel type of molecular chaperones, occurs in human gray and white matter ischemic lesions. METHODS: We prepared formalin-fixed, paraffin-embedded sections from 33 autopsied brains, consisting of 7 normal controls, 4 cases with cerebral thrombosis, 5 cases with cerebral embolism, 8 cases with multiple lacunar infarctions, and 9 cases with Binswanger disease. Deparaffinized sections from all cases were immunostained with anti-14-3-3 antibodies using the avidin-biotin-peroxidase complex method, and some sections were also double-immunostained for 14-3-3 and glial markers. RESULTS: In the normal control brains, 14-3-3 immunoreactivity was mainly localized to the neuronal somata and processes. Strongly 14-3-3-immunopositive astrocytes were distributed in the infarct lesions and were particularly abundant in infarcts at the chronic stage. Intensely 14-3-3-immunolabeled astrocytes were also observed in the ischemic white matter lesions, and in the severely affected white matter lesions from patients with Binswanger disease, dense 14-3-3 immunoreactivity was found in clasmatodendritic astroglia as well as in reactive astrocytes. CONCLUSIONS: Our results suggest that 14-3-3 proteins may be induced mainly in astrocytes from human cerebrovascular ischemic lesions, and that the upregulated expression of 14-3-3 proteins in astrocytes may be involved in the formation of astrogliosis.

Cultured murine dermal fibroblast-like cells from senescence-accelerated mice as in vitro models for higher oxidative stress due to mitochondrial alterations.

The senescence-accelerated mouse is a model for senescence acceleration, a higher oxidative stress status, and age-associated disorders. We studied whether fibroblasts cultured from accelerated senescence-prone SAMP11 mice could be used as in vitro models for oxidative stress in senescence. Dichlorofluorescein and hydroethidine assays demonstrated that cells from SAMP11 mice produced more reactive oxygen species than did cells from accelerated senescence-resistant SAMR1 mice. These differences were not due to the defective induction of antioxidants. Double labeling with hydroethidine and MitoTracker Green revealed that most of the reactive oxygen species were generated within the mitochondria. Nonyl acridine orange and JC-1 assays showed an increase in the mass of the mitochondria, especially those with low membrane potential, in SAMP11 cells. Ultrastructurally, mitochondria with degenerative morphology were increased in SAMP11 cells with longer culture periods. These results suggest that cells from SAMP11 mice are useful models for spontaneous higher oxidative stress in vitro due to dysfunctional mitochondria.

[Prediction of conversion from amnestic mild cognitive impairment to Alzheimer's disease using proton magnetic resonance spectroscopy].

Amnestic mild cognitive impairment (aMCI) has been considered to be a transitional state between healthy aging and very mild Alzheimer's disease (AD). Most patients with aMCI convert to AD over time, but some of them remain stable as aMCI. In this study, 22 patients with aMCI underwent proton magnetic resonance spectroscopy (1H-MRS) of hippocampus and posterior cingulate cortex. Ten patients converted to AD had significantly lower N-acetylaspartate (NAA) concentrations in both hippocampi when compared to 12 patients remained stable to be aMCI. The mean NAA concentration of both hippocampi equal to or lower than 7.6 mmol/l predicted conversion to AD at 1.0 sensitivity and 1.0 specificity and the area under receiver operating curve (ROC) was 1.0. Absolute quantification of 1H-MRS of hippocampus seems to be a useful marker for predicting conversion to AD from patients with aMCI .