Proteinase-resistant prion protein accumulation in Syrian hamster brain correlates with regional pathology and scrapie infectivity.

Multiple lines of evidence indicate that PrPSc, found only in scrapie, is a necessary component of the infectious scrapie agent. Equally compelling is the evidence that its accumulation in the brain causes the neuropathology characteristic of scrapie. We measured the regional concentration of PrPSc in nine brain regions throughout the course of scrapie in the Syrian hamster following intrathalamic inoculation of prions. PrPSc was compared to the regional concentration of glial fibrillary acidic protein, a measure of reactive astrocytic gliosis. PrPSc was detected first in the thalamus 14 to 21 days postinoculation and next in the septum at 28 days. Initiation of PrPSc synthesis and accumulation in the thalamus was attributable to the inoculum and in the septum to ventricular spread of de novo synthesized PrPSc. The timing and pattern of PrPSc accumulation in all other brain regions suggested transmission along neuroanatomic pathways. Reactive astrocytic gliosis followed PrPSc accumulation in each region by 1 to 2 weeks. Brain PrPSc, determined by summing the concentrations in each brain region, correlated well with scrapie infectivity titers throughout the course of infection (correlation coefficient = 0.975; slope of linear regression line = 1.136). Our results support the hypothesis that PrPSc participates in both the etiology and pathogenesis of prion diseases.

A potential role for human herpesvirus type 6 in nervous system disease.

Human herpesvirus type 6 (HHV-6) is a new representative of the herpesvirus family which was associated with a spectrum of diseases, including myalgic encephalitis, meningitis and the chronic fatigue syndrome. We set out to study the potential role of HHV-6 in multiple sclerosis (MS) (n = 21), facial palsy (FP) (n = 19) and Guillain-Barré-syndrome (GBS) (n = 7). Results were compared with a control group (CG) (n = 16). We analyzed paired samples of serum and cerebrospinal fluid (CSF) with the polymerase chain reaction (PCR) for the presence of HHV-6 DNA. The studies were complemented by ELISA determination of serum antibodies against HHV-6. In the MS group we detected HHV-6 DNA in the CSF from three of 21 (14.3%) patients but not in the corresponding serum samples. In FP, GBS and controls CSF and serum PCRs were negative in all cases. HHV-6 serum antibody titers were significantly higher in MS compared with FP, GBS and controls. These findings suggest that HHV-6 may play a role in MS.

Novel twelve-generation kindred of fatal familial insomnia from germany representing the entire spectrum of disease expression.

We present a novel large German kindred of fatal familial insomnia (FFI) consisting of three branches and comprising more than 800 individuals of 12 generations, the largest pedigree of any familial prion disease known today. There is a wide spectrum of clinical presentations leading to misdiagnoses of Olivo-Ponto-Cerebellar Atrophy (OPCA), Parkinson's or Alzheimer's disease in addition to Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker (GSS) syndrome. Molecular genetic analysis of the prion protein gene (PRNP) confirmed the mutation D178N segregating with methionine at the polymorphic codon 129 of PRNP in all 7 patients examined. This polymorphism at codon 129 is supposed to discriminate between familial CJD (fCJD) and FFI; the 129M allele determines FFI and 129V fCJD. Furthermore, heterozygosity at this site appears to induce prolonged disease duration as compared to the homozygous condition. The variability of the clinical and pathological findings documented for our patients indicates the difficulty in establishing the diagnosis of FFI on clinical and on pathological grounds alone. In three cases (IX-97, XI-21, V-2) followed up by us prospectively insomnia was an early and severe symptom; however, in case notes analyzed retrospectively this symptom was frequently missed. In contrast to previous reports and in agreement with recent studies we cannot confirm a clear relationship between the status of the M/V polymorphism at codon 129 and the age-of-onset of this disease.

NGF content in the cerebral cortex of non-demented patients with amyloid-plaques and in symptomatic Alzheimer's disease.

There is increasing evidence that in Alzheimer's disease nerve growth factor (NGF) protein and NGF mRNA content in postmortem cortex is not decreased, but may even be elevated although the NGF-sensitive cholinergic basal forebrain neurons are preferentially affected. However, only little is known about the early pathophysiological events leading to Alzheimer's disease. We therefore measured the post-mortem NGF concentrations in temporal and frontal cortex of Alzheimer's disease patients, non-demented controls without Alzheimer's disease-related pathology, as well as non-demented patients with beta A4 plaques who might be classified as 'preclinical' cases. In the Alzheimer's disease group we found up to 43% increase in NGF concentrations in the frontal and temporal cortex as compared to the two other groups. In a subgroup analysis of the non-demented patients with plaques, NGF concentrations were lower in the frontal cortex when beta A4 plaques were present (46% of the control temporal area) than in patients without evidence of frontal plaques (81% of the control temporal area). This NGF decrease was paralleled to a similar decrease of choline acetyltransferase activity, which is regulated by NGF in the cholinergic basal forebrain. These findings support the hypothesis of lower cortical NGF content at the onset of plaque formation and of elevated NGF levels in the clinically manifest and neuropathologically advanced stage of the disease.

Early age of onset in fatal familial insomnia. Two novel cases and review of the literature.

Fatal familial insomnia (FFI) is a prion disease exhibiting the PRNP D178N/129M genotype. Features of this autosomal dominant illness are progressive insomnia, dysautonomia, myoclonus, cognitive decline and motor signs associated with thalamic nerve cell loss and gliosis. In contrast to the new variant of Creutzfeldt-Jakob disease (vCJD) the onset of FFI is in middle to late adulthood. We report two male patients who belong to a large German FFI kindred. They were examined clinically, and postmortem neuropathological examination was carried out in collaboration with the German reference centre for prion disease. Additionally, the prion protein gene (PRNP) was analysed. To identify further patients with disease onset under 30 years of age a comprehensive literature review was carried out. Two male patients presented with typical symptoms of FFI at the age of 23 and 24 years. In their kindred, the age of onset has never before been under 44 years of age. Our literature review identified five additional early onset cases who died at age 21 to 25 years. In all 22 reviewed FFI families the median manifestation age was 49.5 years. Although phenotypic variability of FFI is common, age of onset under 30 years has been considered to be a hallmark of vCJD with a mean manifestation at 27 years of age. Our findings underline that in addition to vCJD, FFI must be considered in cases of young-onset prion disease. This has considerable impact on clinical management and genetic counselling.

Effect of strenuous exercise on agonist-induced platelet cytosolic calcium in man.

Hypertension, which is attenuated by regular aerobic exercise, is associated with an increase in cytosolic platelet calcium [Ca+2]i. How aerobic exercise might lower blood pressure is unknown. We tested the hypothesis that exercise would influence the agonist-induced effect on platelet cytosolic calcium [Ca+2]i. Twenty, healthy normotensive men between 20 and 60 years of age (five per decade) were studied while resting supine for 30 min and after bicycle ergometry at a work load sufficient to achieve a heart rate of 200 beats per min minus age in years. On the next day, the protocol was repeated with the subjects exercising at 75% their maximum heart rate for 6 min. Venous blood was obtained from an indwelling cannula. Exercise had no effect on total or ionised serum calcium values. Adrenaline values increased from 0.2 +/- 0.03 to 0.55 +/- 0.1 (s.e.m.) nmol/l (P < 0.05), while noradrenaline increased from 1.46 +/- 0.18 to 4.72 +/- 0.44 nmol/l (P < 0.05). Resting platelet [Ca+2]i concentrations were 95.4 +/- 3.9 and 94.4 +/- 3.0 nmol/l on the two study days. The values were not correlated with age or level of fitness. The platelet [Ca+2]i was 99.2 +/- 4.2 nmol/l after exercise, not different from the resting values. Platelet activation with adrenaline and thrombin across a wide range of doses resulted in prompt increases in [Ca+2]i, which were 50% less in platelets after exercise than at rest (P < 0.05). Activation with angiotensin (Ang) II, on the other hand, was less pronounced and less clearly influenced by exercise. We conclude that exercise influences the platelet activation state and reactivity. The decreased [Ca+2]i responses to adrenaline and thrombin suggest that [Ca+2]i stores were in part depleted at exercise compared to rest, an effect not observed with Ang II perhaps because of the smaller number of Ang II-operative receptors on platelets.

The relationship of Alzheimer-type pathology to dementia in Parkinson's disease.

Lewy body degeneration of the subcortical nuclei other than the substantia nigra is common in PD and may represent the substrate for a higher vulnerability to dementia in patients with PD. Cortical pathologies of Alzheimer and Lewy body type seem to be the major determinants of dementia. The prevalence of Alzheimer's disease is not increased in PD, but "early" cortical Alzheimer lesions (usually sub-clinical in normal controls) are frequently associated with dementia in PD. Furthermore, dementia in PD is heterogeneous and should always prompt the clinician to search for treatable causes.

Amyloid beta-peptide and its relationship with dementia in Lewy body disease.

Cerebral cortical Lewy bodies occur in a spectrum of clinical syndromes including Parkinson's disease (PD) with and without dementia, and dementing conditions clinically resembling Alzheimer's disease with few or without parkinsonian features. It is unclear whether these conditions are variants of one disease process or represent pathogenetically distinct entities. Here we compared the cortical pathology in post mortem brains of three groups representing the predominant clinical phenotypes of Lewy body disease, including 27 non-demented cases of PD, 23 demented PD cases, and 11 cases of Lewy body disease who initially presented with dementia and showed only limited features of parkinsonism during the course of their illness. In addition to neuropathology, computer-assisted histoblot analysis was used to assess cortical amyloid beta-peptide deposition. There was wide overlap of the pathomorphometric features between the two groups of demented cases. It appears that substantial cortical Alzheimer-type pathology present in most demented cases contributes significantly to the development of dementia in Lewy body disease.

How to run a "brain bank"? Clinical and institutional requirements for "brain banking".

"Brain Banking" or prospective sampling of tissues relevant to the study of neurological disease is a complex task which needs organization at various levels of operation such as the establishment of a donor system, recruitment of clinical assessment centres, establishment of standardized assessment protocols, the inauguration of logistic structures for brain removal and transport to the bank, proper storage of patient data and tissues, histological verification of the disease and availability of tissue and clinical data to researchers. This effort certainly promises to bear fruit since there is a striking lack of precise prospective studies into etiology and pathogenesis in most neurological diseases especially in the field of the neurodegenerative diseases.

Amyloid beta-peptide and the dementia of Parkinson's disease.

It is not known whether an increased incidence of dementia in patients with Parkinson's disease (PD) is due to a higher incidence of Alzheimer's disease (AD) or to "early" Alzheimer-type pathology. To determine whether amyloid beta-peptide (A beta) of AD occurs more frequently in brains of patients with PD, we examined 50 cases and 79 controls by using histoblots for A beta. Twenty-three cases with PD had dementia, including all nine with A beta distributed throughout the entire cerebral cortex; three of these cases had AD. In contrast, five of 17 controls with comparable A beta accumulation were not demented. Neither AD nor A beta deposition was increased in PD, furthermore, there was no statistical correlation between the amount of A beta and the number of Lewy bodies in cerebral cortex. In 14 patients with PD in whom dementia was unrelated to A beta, there was cerebral vascular disease (four), numerous cortical Lewy bodies (three), or hydrocephalus (two); in five further cases, dementia was not well explained by histopathologic changes. Our data found no increase of either AD or "early" Alzheimer-type pathology in cases of PD; however, a synergistic effect between the two pathologies was suggested as contributing to dementia.

Morphological overlap between corticobasal degeneration and Pick's disease: a clinicopathological report.

An 81-year-old woman died after a 3-year history of a progressive nondementing akinetic-rigid syndrome. Initially, there was a moderate response to levodopa treatment. Subsequently she developed postural tremor, loss of upward gaze, and frequent falls suggestive of Steele-Richardson-Olszewski syndrome (SROS). Macroscopical examination showed depigmentation of substantia nigra and locus ceruleus. Histology revealed occasional swollen achromatic neurons predominantly in frontal cortex, small cortical neurofibrillary tangles, brain stem basophil (corticobasal) inclusions, and Pick bodies. The coexistence of these histopathological markers raises questions concerning their specificity and the basis of a morphological distinction between corticobasal degeneration and Pick's disease.

Absence of disease related prion protein in neurodegenerative disorders presenting with Parkinson's syndrome.

Movement disorders presenting with parkinsonism may share histopathological features with Creutzfeldt-Jakob disease, a spongiform encephalopathy caused by the accumulation of pathological prion protein in brain. To investigate a possible aetiological link between these conditions and Creutzfeldt-Jakob disease, histoblot immunostaining for pathological prion protein was carried out in 90 cases including idiopathic Parkinson's disease, multiple system atrophy, diffuse Lewy body disease, Steele-Richardson-Olszewski syndrome, corticobasal degeneration, and Pick's disease. Pathological prion protein was identified in four controls with Creutzfeldt-Jakob disease but not in any of the other diseases examined. The findings suggest that an aetiological role for prions in these movement disorders is unlikely. Histoblotting provides a useful method for screening large areas of tissue for the presence of pathological prion protein and may be helpful in the differential diagnosis of difficult cases.

Effects of acute hypermagnesaemia on intracellular calcium concentration and adrenergic activity.

The effects of acute hypermagnesaemia on intracellular free calcium and adrenergic activity were investigated in six normotensive volunteers given intravenous magnesium sulphate for 3 h. The free calcium concentration in platelets decreased after the first hour of infusion (P less than 0.05), but did not remain significantly depressed after 2 and 3 h of continued infusion. Plasma noradrenaline increased during the infusion (P less than 0.05), with no change in plasma adrenaline. The results demonstrate that the effects of intravenous magnesium sulphate on free intracellular calcium and plasma catecholamines are similar to those described with calcium antagonists.

Regional mapping of prion proteins in brain.

Scrapie is characterized by the accumulation of a protease-resistant isoform of the prion protein PrPSc. Limited proteolysis and chaotropes were used to map the distribution of PrPSc in cryostat sections of scrapie-infected brain blotted onto nitrocellulose membranes, designated histoblots. Proteolysis was omitted in order to map the cellular isoform of the prion protein (PrPC) in uninfected brains. Compared with immunohistochemistry, histoblots increased the sensitivity for PrPSc detection and showed different patterns of PrPSc accumulation. In Syrian hamsters with Sc237 scrapie, the most intense PrPSc signals occurred in sites with relatively little PrPC, suggesting that aberrant localization of prion protein may be an important feature in the pathogenesis of prion diseases. Immunostaining of PrPSc in white-matter tracts suggested that prions spread along neuroanatomical pathways. PrPSc immunostaining in histoblots was quantitated by densitometry, permitting assessment of the extent of PrPSc accumulation within specific structures. Histoblots were also useful in localizing PrPCJD and beta/A4-amyloid peptide in the brains of patients with Creutzfeldt-Jakob disease and Alzheimer disease, respectively.

Replication of distinct scrapie prion isolates is region specific in brains of transgenic mice and hamsters.

Scrapie prions are composed largely, if not entirely, of PrPSc molecules. The prion isolates Sc237 and 139H exhibit markedly different incubation times in Syrian, Armenian, and Chinese hamsters, as well as in transgenic (Tg) 81 mice expressing Syrian hamster PrP (SHaPrP). Repassage of prions from transgenic mice or Chinese hamsters into Syrian hamsters revealed that the original properties of the prion isolates are retained. When Syrian hamsters were first inoculated with 139H prions and subsequently challenged with Sc237 prions, the incubation period was determined by the faster Sc237 isolate. Regional mapping studies demonstrated different kinetics and patterns of PrPSc accumulation for Sc237 and 139H prions in the brains of Syrian hamsters as well as Tg(SHaPrP)7 mice. That distinct prion isolates induce different region-specific accumulations of PrPSc in brain suggests a novel mechanism for propagation of isolates whereby they replicate in particular sets of neurons. The prion isolates could be targeted to specific CNS cells by differing conformations of PrPSc, post-translational modifications of PrPSc such as Asn-linked glycosylation, or an as yet undetected macromolecule complexed with PrPSc in the prion.

Ischemic stress induces deposition of amyloid beta immunoreactivity in human brain.

The histoblot immunostaining technique for locating and characterizing amyloidogenic proteins was used to obtain information about the relationship of cerebral ischemia/hypoxia to the accumulation of amyloid beta protein (A beta). We investigated brains of 131 subjects (ages 25-94 years, mean 72 years). Three distribution patterns of A beta immunoreactivity were identified: (1) colocalization with diffuse and neuritic plaques of Alzheimer's disease (AD) and aging; (2) diffuse punctuate deposits in the cerebral cortex in association with small vessel cerebral vascular disease ; and (3) cerebral cortical accumulation localized to arterial boundary zones and other regions susceptible to ischemic/hypoxic injury designated "stress-induced deposits" (SID). SID were not identified in tissue sections by immunohistochemical, Congo red or Bielschowsky silver techniques; no histological abnormalities were present in adjacent formalin-fixed tissue sections, SID occurred in subjects with histories of cerebral ischemia, and severe orthostatic hypotension. There was also an association with aging in general and with the incidence of neuritic plaques specifically. These latter findings are consistent with the hypothesis that brain ischemia/hypoxia plays a role in the pathogenesis of AD.

[Early diagnosis and treatment of Alzheimer's disease. Implementation in the doctor's office]. / Frühdiagnostik und Therapie der Alzheimer-Krankheit. Zum Vorgehen in der Praxis.

The efficacy of antidemential agents proven in comprehensive studies and by clinical experience, now justifies an active and positive approach by the general physician to the diagnosis and treatment of patients with dementia. The proposals on how to implement diagnostic and therapeutic measures in the doctor's office comply both with medical quality criteria and the requirements for appropriateness of treatment and considerations of economy stipulated by German law. They therefore provide the basis for a modern diagnostic work-up and treatment strategy, which will also meet economical demands.

Donepezil for Alzheimer's disease in clinical practice--The DONALD Study. A multicenter 24-week clinical trial in Germany.

This multicenter open-label clinical trial was designed to investigate the safety and efficacy of donepezil, a selective acetylcholinesterase inhibitor, in the treatment of Alzheimer's disease (AD) in routine clinical practice in Germany. A total of 237 patients with mild-to-moderate AD were treated with donepezil for 24 weeks, 186 completed the study according to the protocol. In the completer group, mean MMSE score for efficacy showed an improvement from baseline of +1.6 points at week 12 (95% CI +1.1 to +2.1) and of +1.1 points at week 24 (95% CI +0.5 to +1.7). In more than 80% of the patients, global tolerability was rated to be very good or good. There were only insignificant effects on ECG parameters. This study confirms the results obtained in previous double-blind trials, which showed that donepezil is effective and well tolerated in patients with mild-to-moderately severe AD.