Oxidative stress in Alzheimer's disease hippocampus: a topographical study

Advanced glycation end-products (AGEs) and their receptor (RAGE) are molecules related to oxidative stress demonstrated in aging and in several pathological disorders including Alzheimer's disease (AD). Aging has been considered the main risk factor for AD. Amyloid deposits (Aβ-D) and neurofibrillary tangles (NFT) are pathological changes related to AD involving hippocampal regions. Different degrees of AD pathology have been described according to distribution of NFTs in different topographical regions of hippocampus and cerebral cortex. The hippocampus shows a selective vulnerability under several noxes especially those including hypoxia. Hypoxia in the nervous tissue induces oxidative stress. In an attempt to find out more about anatomical distribution of the oxidative stress through hippocampal regions in AD, a collection of brains were studied. Samples from deceased patients who had suffered from AD and from age-matched controls were immunohistochemically studied with AGE and RAGE antibodies according to a topographical division of the hippocampus and brain cortical regions. Results suggest that an oxidative stress pathway starts in the CA3 sector progresses to CA1 and then continues to other hippocampal and cortical areas building a pathoclitic pathway for Alzheimer's disease progression.

Brain-derived neurotrophic factor and neurotrophin 3 in schizophrenic psychoses

Disturbed neural development has been postulated as a crucial factor in the pathophysiology of schizophrenic psychoses. The neurobiochemical basis for such changes of cytoarchitecture and changed neural plasticity could involve an alteration in the regulation of neurotrophic factors. In order to test this hypothesis, BDNF and NT-3 levels in post-mortem brain tissue from schizophrenic patients were determined by ELISA. There was a significant increase in BDNF concentrations in cortical areas and a significant decrease of this neurotrophin in hippocampus of patients when compared with controls. NT-3 concentrations of frontal and parietal cortical areas were significantly lower in patients than in controls. These findings lend further evidence to the neurotrophin hypothesis of schizophrenic psychoses which proposes that alterations in expression of neurotrophic factors could be responsible for neural maldevelopment and disturbed neural plasticity, thus being an important event in the etiopathogenesis of schizophrenic psychoses.

Brain-derived neurotrophic factor and neurotrophin-3 levels in Alzheimer's disease brains

In the present study, we investigated the levels of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) in post-mortem brain tissue of Alzheimer's disease (AD) patients, and we observed a significant increase of BDNF concentration in hippocampus and parietal cortex of AD patients, as well as a negative correlation between NT-3 levels and age in hippocampus and putamen of control subjects, and for BDNF in frontal cortex. A defining feature of AD is the post-mortem identification of neuritic plaques and neurofibrillary tangles in the brain, however, a more significant neuropathological finding is the degeneration of cholinergic neurones of the basal forebrain, critically involved in memory and cognition. Neurotrophic factors are partly responsible for the maintenance of neuronal function and structural integrity in the adult brain. Our results provide, therefore, evidence that, under conditions of progressive neurodegeneration the brain stimulates the over expression of certain neurotrophic factors as a possible mechanisms of compensation, and that during senescence the expression of these molecules is regulated.

Correlation between Apolipoprotein-E polymorphism and Alzheimer's disease pathology

Alzheimer's disease (AD) and small vessel disease dementia (SVDD) are common causes of dementia. The ApoE genotype has been proposed as a risk factor for AD. The frequency of the three ApoE alleles was correlated with the neuropathological changes of AD (senile plaques, neurofibrillary tangles and amyloid angiopathy) and SVDD (status lacunaris, status cribosus, leucoencephalopathy, micronecrosis and vascular fibrohyalinosis) in order to validate previous ApoE genotyping results in AD and to identify pre-clinical AD. Representative cerebral regions (cortex, gyrus cinguli, putamen, hippocampus, white matter) from 28 AD cases, 7 SVDD and 38 non-neurological controls were studied using classical histological techniques and immunohistochemistry for tau protein and amyloid-beta. The frequency of the ApoE allele 4 was significantly increased not only in AD patients but also in aged controls. However, following a detailed histopathological examination was found 62% of this group to exhibit histological changes associated with AD in limited brain areas (entorhinal region, hippocampus and adjacent temporal cortex or entorhinal region and hippocampus, or only in the entorhinal region), but 87% of these cases were found to be ApoE4 positive. The significant differences found in the distribution of ApoE allele frequencies were more marked when these cases were excluded from the control group and included as AD cases. In contrast, the frequency of the ApoE allele 2 is significantly increased in SVDD patients. Using histological techniques we confirmed the clinical diagnoses of all cases and classified the AD patients according to the severity of cortical pathology related to AD, while re-grouping from the control group those cases which had no clinical history of the disease but exhibited typical AD and SVDD histological lessions which could be considered as "pre-clinical" forms of these diseases.

Biologic parameters that correlate with the prognosis of human gliomas

Much clinical and biologic data have been processed in the search for useful objective parameters to predict brain tumor behavior. Seventy cases of astrocytic glioma collected by a single clinical team were studied using a full complement of clinical procedures: follow up (7 years), histologic analysis, DNA content estimation, and cell kinetics by flow cytometry. Proliferating cell nuclear antigen (PCNA) was determined by immunocytochemical-coupling flow cytometry (PFC) and also by counting under light microscopy (PIHC). A statistical evaluation was carried out to establish the usefulness of several parameters for glioma prognosis. The cases were histologically classified as 14 low-grade astrocytomas, 20 anaplastic astrocytomas, and 36 glioblastomas multiforme. The survival curve showed significant differences between histologic groups. Diploid populations were more frequent in low-grade astrocytomas, and aneuploid tumors often had increased S-phase and proliferative fractions. The PCNA-labeled index (PCNA-LI) increased with malignancy and correlated with histologic grading (P = 0.01). The PCNA-LI and age segregated low- from high-grade astrocytomas (including anaplastic astrocytoma and glioblastoma multiforme), but none of the variables considered differentiated anaplastic astrocytoma from glioblastoma multiforme. The Cox regression test displayed significant values for age, histologic diagnosis, and PCNA determinations when considered in tandem. Discriminant analysis obtained a function integrating age and specifically PIHC-LI to help in the prognosis of doubtful cases. The results emphasize the importance of parameters integrating different variables in an attempt to provide an accurate prognosis, the most significant being age, histopathologic diagnosis, and the proliferative fraction determined by PCNA.

Increased frequency of the alpha-1-antichymotrypsin T allele in cerebral amyloid angiopathy

Cerebral amyloid angiopathy (CAA) is a process of unknown etiology characterized by amyloid deposition in the wall of small cerebral and meningeal blood vessels. CAA is also a feature of Alzheimer's disease (AD) and of a subgroup of elderly people. Alpha-1-Antichymotrypsin (ACT) is a serum glycoprotein frequently associated with vascular and senile plaque amyloid. The ACT gene is known to have a bi-allele polymorphism that causes a simple amino acid substitution. In an attempt to clarify the possible role of ACT polymorphism in AD and in cases of CAA, the ACT genotype was investigated in AD, CAA, and intellectually intact controls. Representative brain areas (cerebral cortex, hippocampus, putamen, white matter, and gyrus cinguli) from all cases were studied using classical histologic staining techniques (hematoxylin-eosin (HE), Mallory's thrichromic or alkaline congo red stain), and immunohistochemistry for tau and beta-amyloid proteins. There was a significantly increased T allele and TT genotype frequency in the CAA group, but not in the AD group, suggesting a role for the ACT genotype in the development of vascular lesions. The presence of the apolipoprotein E4 allele (ApoE4) did not correlate with the ACT-A allele, as previously reported, and appeared to be independent of the risk for developing AD.

Apolipoprotein E genotype in Spanish schizophrenic patients

Apolipoprotein E (ApoE) is a lipoprotein that, in the central nervous system, is thought to play a role in neuronal growth and repair. ApoE has three isoforms (ApoE2, ApoE3 and ApoE4) coded by three different alleles (epsilon2, epsilon3 and epsilon4). Evidence from family, twin and adoption studies suggest that there is an important genetic contribution to the etiology of schizophrenia. Schizophrenia is in some cases associated with cognitive impairment similar to that of Alzheimer patients; therefore, one may postulate that the ApoE gene, whose role in the dementia of Alzheimer's type has been clearly demonstrated, may also be involved in schizophrenia. In the present study, we have genotyped 114 schizophrenic Spanish patients and 94 healthy matched controls, and found no association between the ApoE genotype and schizophrenia. Subdivision of patients in clinical subgroups showed a slight increase of ApoE4 in early-age onset of the disease and a slight decrease in positive family history for psychiatric diseases; the group with a poor response to neuroleptic drugs had a lower ApoE2 allele frequency. However, as the differences did not reach statistical significance, we cannot draw evidence of an association. Our negative data do not support an involvement of ApoE in schizophrenia, and suggest that the underlying mechanism for the cognitive impairment found in schizophrenic patients is not related to that of Alzheimer's patients nor to a higher prevalence of the ApoE allele 4.

Expression of vascular endothelial growth factor (VEGF) and platelet-derived growth factor receptor-beta (PDGFR-beta) in human gliomas

The growth of solid tumors is highly dependent on vascular proliferation. Vascular endothelial growth factor (VEGF), the main mediator of angiogenesis, and platelet-derived growth factor receptor-beta (PDGFR-beta), receptor for the potent mitogen PDGF, are two indicators of the angiogenic potential of human gliomas. We studied a series of 57 surgical biopsies of astrocytic neoplasms by immunohistochemistry to elucidate the relationship between tumor proliferation, quantified as Ki67-LI, and the expression of these two proteins. Ki67-LI increases throughout histological malignancy, although staining in endothelial cells has rarely been recorded. Elevated amounts of VEGF-positive tumor cells (VEGF-LI) were found in anaplastic astrocytomas and glioblastomas, mainly around areas of necrosis, cysts, or edema. Endothelium of blood vessels was consistently stained. PDGFR-beta positivity was found in glomeruloid formations and in tumor cells, excluding pilocytic astrocytomas. Multinucleated giant cells and perivascular tumor cells were positive in glioblastomas. In addition, peritumoral microglia-like cells were also stained in some cases. Statistical correlation was only found between PDGFR-beta and Ki67 LIs. In conclusion, VEGF as permeability factor is involved in the development of secondary neoplastic changes, whereas PDGFR-beta is directly correlated to proliferation indexes. Strong expression of VEGF and PDGFR-beta found in endothelium and tumor cells would seem to support a combined role in tumoral neoangiogenesis.

Evaluation of neuronal loss, astrocytosis and abnormalities of cytoskeletal components of large motor neurons in the human anterior horn in aging

In order to identify possible morphological changes which occur in the anterior horn of normal individuals during aging, 40 controls with no neurological disease were studied. Brain and spinal cord tissue was processed according to a brain banking protocol. Controls were grouped according to age in 10 year intervals. Serial sections (20 microm) of formalin fixed, paraffin-embedded tissue were obtained, from each cervical, thoracic and lumbar spinal cord segment. Every 5th section (until 2 mm) was stained with haematoxylin and eosin and the numbers of motor neurons in the anterior horn counted at x400 magnification. Descriptive statistical analysis was performed using the SPSS program. Parallel sections (5 microm) of the same spinal segments were immunostained with a panel of antibodies including glial fibrillary acidic protein (GFAP), tau, ubiquitin and two phosphorylated neurofilaments subunits. Significant neuronal loss with aging was found by regression line analysis where three equations were used to calculate the number of motor neurons by age in each spinal segment. In 24/40 cases spheroids were observed and they were more numerous in the lumbar segment. GFAP staining revealed a distinctive cellular pattern in the anterior horn of oldest cases. Large and intensely stained astrocytes were seen in the anterior horn of cases aged over 75 years. The number of astrocytes increased progressively with age up to 70 years. Some of the changes observed in the present study may be the result of a selective vulnerability of large motor neurons to aging which could play an important role in the progression of MND. Most of these changes may also have similar pathophysiological mechanisms.

Ethical aspects to be considered in brain banking

A brain bank is a prospective source of adequately collected and preserved tissues of the central nervous system obtained via a donor program, which are supplied for neurobiological research. Brain tissue banks collect brains, serum and cerebro-spinal fluid from patients suffering from neurological disorders such as Alzheimer's diseases, Parkinson's disease and multiple sclerosis for diagnostic purposes and for the development of future diagnostic tests. To create and develop the right infrastructure underlying brain bank activities, one should have a medico-legal and ethical support according to local legislation. From an ethical point of view, brain bank activities can be divided into the following categories: a) factors related to the donor program; b) factors related to handling and management of organs; c) factors related to scientific research. The present paper deals with the above mentioned issues according to world-wide recognised ethical considerations and recommendations of several official statements, and specifies the objectives of the European Brain Bank Network (EBBN).

Aging and the nigro-striatal pathway

Aging is associated with a progressive impairment in motor function. This feature, together with the decline in mental function, could be considered as an aging syndrome which may finally compromise the ability of the elderly to maintain an active, independent life-style. In the present paper a wide variety of morphological aspects, which have been classically related to brain aging and others such as cytoskeletal changes, the role of growth factors and molecular changes, will be reviewed focusing on aging of the nigrostriatal pathway. In addition to sharing features of aging common to other structures, it is likely that the nigrostriatal pathway has specific characteristics derived from its particular molecular characteristics and/or from a selective vulnerability to aging. To gain further insight into the aging syndrome, the acquisition of rigorous criteria for selecting control cases is paramount. The improvement of methods for the preservation of human tissue is also crucial.

Variants in neurotrophic factor genes and schizophrenic psychoses: no associations in a Spanish population

Possible associations between schizophrenic psychoses, a ciliary neurotrophic factor (CNTF) null mutation and a neurotrophin in 3 (NT3) bi-allele polymorphism were investigated in a Spanish population. The sample consisted of 107 patients suffering from schizophrenic psychoses and 100 healthy volunteers. There was no statistical difference in the frequencies of the mutant CNTF allele in the index and control groups (0.125 vs. 0.121). The frequency of the rare NT3 allele (Glu) was very low and similar in both groups (0.005). Previous findings supporting the involvement of these genetic markers in the pathogenesis of schizophrenic psychoses were thus not confirmed. In light of neurodevelopmental hypotheses of schizophrenia, however, genes coding for neurotrophic factors remain interesting susceptibility loci in schizophrenia research. Subsequent studies should not focus exclusively on genetic alterations but also take into account secondary changes of the neurotrophic factor system at the mRNA and protein levels. Further, the current unsatisfying operationalized classification of the heterogeneous syndrome 'schizophrenia' remains a crucial problem that could be partially resolved by introducing more differentiated diagnoses defined on the basis of neurobiological criteria.

Cerebellar cortex delayed maturation in sudden infant death syndrome

The cerebellum shows afferent and efferent connections with intrinsic bulbar nuclei and plays an important role in respiration and cardiovascular control. Pathological and neurochemical abnormalities of bulbar nuclei including the arcuate nucleus have been postulated in sudden infant death syndrome (SIDS). Most of these abnormalities have been related to impairment in brain development. The cerebellar cortex has a well-documented evolution from fetal life until infancy; thus, it may be a very good model to assess brain maturation in SIDS. The present study was conducted to investigate changes in the cerebellar cortex in 19 SIDS cases compared with 12 age-related controls using morphological, quantitative, and statistical approaches. Five-microns paraffin sections from the midsagittal cerebellar vermis were stained with hematoxylin and eosin (H&E). Immunohistochemical staining was carried out using a polyclonal antiserum to glial fibrillary acidic protein (GFAP). Each case consisted of a 25-microns parallel paraffin section stained with H&E, where the cerebellar external granular layer (EGL) cell density was obtained in one field magnification (x1,000) using an optical dissector procedure on the basis of a stereological method. A statistically significant high EGL cell density, mostly related to the presence of immature bipolar, elongated neuronal cells of the premigratory zone with hyperchromatic, oval or poor differentiated nuclei, was observed in SIDS. In these cases, EGL expressed immunoreactivity for GFAP mainly in the subpial and the postmitotic zone. These findings demonstrate a delayed or slower decline in the number of EGL neurons in SIDS, suggesting either a prolongation of the growth phase related to postnatal cerebellar foliation or a delay in inward migration. These results suggest that in SIDS there is delayed maturation of the cerebellar cortex/EGL, which may support the hypothesized cardiopulmonary control dysfunction, leading to death in a vulnerable period of postnatal development.

Lectin histochemistry of ethylnitrosourea-induced oligodendrogliomas in the rat

Oligodendrogliomas (n = 26) induced by ethylnitrosourea (ENU) in wistar rats were examined to assess the lectin specificity to oligodendroglial membranes. Two different types of oligodendrogliomas were found in our material: an isomorphous type (n = 12), and a polymorphous type (n = 14). The first one, with two variants according to its size, macro- (n = 9) and microtumors (n = 3), had predominantly a honey-comb pattern with 'clear halos' around the nuclei without anaplasia. The second type, composed mostly by macrotumours, was anaplastic, with high cellular density, necrosis and intratumoral hemorrhages. Peanut agglutinin (PNA) labelled plasma membranes of well-differentiated cellular components of the first group. The tumoral oligodendrocytes lost the property to bind PNA in the second group of tumours, while Concanavalin A (Con A) showed affinity to intracytoplasmic structures of these tumours. PNA is a reliable marker of oligodendroglial plasma membrane of well-differentiated ENU-induced oligodendrogliomas. This experimental model, using PNA and Con A, may have important clinical applications regarding the biological behaviour of this type of neoplasm.

Phosphoglycerate mutase, 2,3-bisphosphoglycerate phosphatase and creatine kinase activity and isoenzymes in human brain tumours

The distribution of phosphoglycerate mutase (EC 5.4.2.1, PGM), 2,3-bisphosphoglycerate phosphatase (EC 3.1.3.13, BPGP) and creatine kinase (EC 2.7.3.2, CK) activity and isoenzymes in various regions of adult human brain and in brain tumours (astrocytomas, anaplastic astrocytomas, glioblastomas and meningiomas) has been determined using electrophoresis. PGM and cytosolic CK exist in mammalian tissues as three isoenzymes that result from the homodimeric and heterodimeric combinations of two subunits [types M (muscle) and B (brain)] coded by separated genes. In addition, a dimeric form and an octameric form of mitochondrial CK exist in mammals. Type BB-PGM was the major PGM isoenzyme found in normal brain, although type MB-PGM and type MM-PGM were also detected. All brain tumours possessed lower PGM activity than normal brain, and meningiomas showed higher BPGP activity. In astrocytic tumours, the proportion of type MB- and type MM-PGM decreased, and in meningiomas these isoenzymes were not detected. Type BB-CK and mitochondrial CK were the only CK isoenzymes detected in normal brain. Astrocytomas possessed lower CK activity than anaplastic astrocytomas and glioblastomas and, in addition, tended to possess lower CK content than normal brain. No qualitative changes of the normal CK isoenzyme pattern were observed in the tumours.

Prognostic analysis of astrocytic gliomas correlating histological parameters with the proliferating cell nuclear antigen labelling index (PCNA-LI)

Eighty out of 250 cases of astrocytic glioma collected from a practice served by a single clinical team over a 15-year period were studied using a full complement of clinical, follow up, histopathological analysis and proliferating cell nuclear antigen (PCNA) immunostaining for the obtention of the PCNA-labelling index (LI). A statistical evaluation and discriminant analysis were carried out with the aim of clarifying the importance of various parameters as predictors of tumor behaviour. Data are correlated with survival (with a 10-year follow up). A significant correlation with survival was found when histological grouping and the PCNA-LI were studied with the Cox test. Most significant features were histological as detected using classical techniques including histological grading. The utilization of objective values (mitosis, cellular density and necrosis) appears to be useful in grading astrocytic tumors. Our results emphasize the importance of cytological, histological and PCNA-LI parameters as predictors of tumor behaviour.

Homozygosity at the dopamine D3 receptor gene in schizophrenic patients

Dopamine receptors have long been implicated in the etiology of schizophrenia. It has been reported an association of schizophrenia with homozygosity at the dopamine D3 receptor gene locus. We have investigated the distribution of a D3 receptor gene polymorphism (BalI) in 107 schizophrenic Spanish patients and 100 healthy matched controls. No statistically significant differences between the patients and control group were detected with respect to either allele frequencies or genotype distribution. However, if not corrected for multiple testing, a correlation was found between homozygosity and early age of onset of schizophrenia (chi 2 = 3.1, df = 1, P = 0.03) and between A1 allele frequency and disorganized and undifferentiated schizophrenia (chi 2 = 3.4, df = 1, P = 0.03; chi 2 = 2.7, df = 1, P = 0.05, respectively). These results suggest the possibility that D3 polymorphisms may be among the physiological factors underlying schizophrenia; though not the determining factor.

Enolase activity and isoenzyme distribution in human brain regions and tumors

The distribution of enolase (EC 4.2.1.11) activity and isoenzymes in various regions of human brain at different ages (from 23 weeks of gestation to 95 years) and in brain tumors has been determined. Total enolase activity increased in all regions with age. No significant differences were found in the relative proportions of alpha alpha-, alpha gamma, and gamma gamma-enolase isoenzymes in the various brain regions, determined by agarose gel electrophoresis. Type alpha alpha-enolase was the predominant isoenzyme, and alpha gamma-enolase represented a substantial proportion of the total enolase activity. Astrocytomas, anaplastic astrocytomas, glioblastomas, and meningiomas possessed lower enolase activity than normal brain. Among astrocytic tumors, total enolase activity correlated with malignancy. Astrocytomas possessed the lowest and glioblastomas the highest enolase activity. All tumors possessed a higher proportion of alpha alpha-enolase and a lower proportion of gamma gamma-enolase than the normal human brain. Among astrocytic tumors, glioblastomas were the tumors with the highest proportion of alpha alpha-enolase and lowest proportion of gamma gamma-enolase.

A null mutation allele in the CNTF gene and schizophrenic psychoses

The maldevelopmental theory postulates disturbances in neural development as crucial factors in the aetiopathogenesis of schizophrenia. Neurotrophic factors, including ciliary neurotrophic factor (CNTF), play a central role in the regulation of such development. A mutation has been described for the CNTF gene, whereby subjects homozygous for the mutation lack CNTF. The polymerase chain reaction was used to amplify the CNTF gene region containing this mutation in whole blood genomic DNA. The mutation was detected by analysis of restriction fragment length polymorphisms. Patients suffering from schizophrenic psychosis (ICD-10 criteria) (51 from Würzburg, 83 from Barcelona), and healthy controls (62 from Würzburg, 50 from Barcelona) were investigated. In the Würzburg group, the frequency of subjects homozygous or heterozygous for the mutation was significantly higher among schizophrenic patients than in controls. However, no difference could be detected in the Spanish sample; the possible reasons for the different allele distribution in the two patient groups is discussed. It is concluded that the CNTF null mutation may be relevant to the aetiopathogenesis of schizophrenia in some patients, but further work is required to identify specifically the patient group for which it is important.

Ependymal changes in sudden infant death syndrome

The ependyma may befall a variety of pathogenic noxae during fetal life, resulting in histological changes which may persist after birth but are without clinical manifestations. Eight of a series of 19 children who died suddenly and unexpectedly, where no explanation as to the cause of death was found at autopsy, were shown to have diverse histological features involving the ependyma. Five micrometer paraffin-embedded brain tissue sections including frontal, temporal, occipital, and ventricular horns as well as the fourth ventricle were stained with hematoxylin-eosin (H&E) and luxol fast blue (LFB). Immunohistochemical stains using antibodies to glial fibrillary acidic protein (GFAP), vimentin and S-100 were also performed. Findings included areas of denuded and/or desquamated ependyma, rosettes in different stages of formation, vacuoles and/or pseudocysts, inflammatory changes consisting in macro- and microglial nodules in the subependymal layer, and gliosis. Chronic brain edema was seen in 4 cases. Our findings indicate that ependymal changes in sudden infant death syndrome (SIDS) cases belong to the prenatal or early postnatal period, thus providing, indirectly, a morphological substrate for the previous existence of a noxa that may also affect other CNS areas, and thus being in the position to produce cardiorespiratory control dysfunction.

Accumulation of wild-type p53 protein in progressive multifocal leukoencephalopathy: a flow of cytometry and DNA sequencing study

p52 protein accumulation in JC virus (JCV)-infected cells of progressive multifocal leukoencephalopathy (PML) has been previously shown. Since many viral proteins are known to bind and stabilize p53, we are addressing the question of whether p53 protein accumulation in PML is the result of its sequestration by JCV and not the outcome of a p53 gene mutation which would prolong its half-life. We have investigated the status of the p53 gene in frozen autopsy brain samples from five PML patients. After isolating genomic DNA, p53 gene exons 2 through 9 were amplified and sequenced. No discrepancies were found in the DNA sequences of exons 2 through 9 and their intron/exon barriers when compared to those published for wild-type p53. On the other hand, dual (p53/DNA) flow cytometry analysis revealed p53 expression above that of the isotypic controls for each case. No aneuploid populations could be identified, however, which seems at odds with the aneuploid status normally associated with mutation-induced p53 dysfunction. These results indicate that the p53 gene harbors no mutations in PML and provide further evidence of p53 protein accumulation in this condition. Since p53 protein buildup in JCV-infected cells is not the consequence of a mutagenic interaction between JCV and the cell genome, we propose instead that p53 accumulation results from its binding and stabilization by JCV T protein.

Synaptophysin in spinal anterior horn in aging and ALS: an immunohistological study

Aged-related spinal cord changes such as neuronal loss have been related to the degree of clinical severity of amyotrophic lateral sclerosis (ALS); morphological data on synapses are, however, wanting. Variations in synaptophysin (Sph) expression in aging and ALS were thus studied at the level of lower motor neurons in 40 controls with non-neurological diseases and 11 cases of ALS. Control sections of formalin fixed paraffin embedded cervical (C7/8), thoracic (T10) and lumbar spinal cord (L5) and C6, C7, C8 and L5 of ALS cases were stained with haematoxylin and eosin, luxol fast blue (LFB), and immunostained with a mouse monoclonal antibody against Sph. The neuropil of the anterior horn (AH) in all control cases demonstrated Sph positivity. A dot-like pattern of positivity of presynaptic terminals on soma of motor neurons and fine immunoreactivity along neuronal processes were observed. A significant reduction of Sph immunostaining was observed in the neuropil with increasing age and 3 different somatic patterns were seen: a- well preserved Sph reactivity around the soma and the proximal dendrites of histologically normal neurons; b- few chromatolytic neurons showing large numbers of dot-like presynaptic terminals around the cell body and in a "fused" pattern; c- intense, diffuse, and homogeneous reactivity of some neurons. Attenuation of Sph reactivity in the AH neuropil, to its complete loss, was observed in all ALS cases. In addition to patterns a-c, two additional microscopic findings were noted in ALS: d- chromatolytic neurons showing complete absence of Sph reactivity; e- absence of Sph reactivity around the soma and the proximal dendrites of histologically normal surviving neurons. Our findings demonstrate that there is a decrease in Sph immunostaining with aging, thus suggesting an alteration in dendritic networks of the AH with aging. Changes in the pattern of Sph immunoreactivity in cell bodies may represent synaptic plasticity and/or degeneration. Reinnervation may also be a possible mechanism as a response to neuronal loss in oldest control cases. Sph reactivity results may thus lend support to the presence of superimposed aging components in ALS cases which may give an insight into explaining the increasing severity of the disease which is encountered with advancing age.

Consensus on minimal criteria of clinical and neuropathological diagnosis of schizophrenia and affective disorders for post mortem research. Report from the European Dementia and Schizophrenia Network (BIOMED I)

The sophisticated analysis of and growing information on the human brain requires that acquisition, dissection, storage and distribution of rare material are managed in a professional way. In this publication we present the consensus of the European work group "European Dementia and Schizophrenia Network", granted by the BIOMED I project of the EU, on minimal neuropathological and clinical requirements to include brains of patients with schizophrenia and affective disorders in post mortem studies. The description of clinical prerequisites in different EU countries and institutions is followed by a consensus on tissue handling, a consensus on minimal neuropathological criteria and a consensus on minimal clinical diagnostic criteria including clinical vignette, family, social, education/professional and general medical histories, general physical history including neurostatus, neurological, psychiatric, medication and general pathological histories, psychostatus, laboratory tests and a history provided by family/health care giver questionnaire. This publication should give help to interconnect different European brain bank centers on a basis of standardized protocols.

Neuronal changes in the substantia nigra with aging: a Golgi study

In order to recognize substantia nigra neuronal changes occurring in aging, 20 human control brains from 13 males and 7 females with a mean age of 61 years (range 20 to 93 years) without neurological disease were examined using the Golgi method. A quantitative study of dendrites and dendritic spines was performed as well as a statistical analysis of obtained data. Parallel sections to the impregnated material were histologically and immunohistologically studied with the aim to identify possible neuronal cytoskeletal abnormalities. Results were compared to changes of substantia nigra reported in other conditions such as Parkinson's disease (PD) and methyl-4-phenylpyridine (MPTP) experimental toxicity. Three different substantia nigra neuronal types were observed. Morphological changes during aging consisted of distorted profile of the cell body and swelling and beading of dendritic branches. The quantitative assessment of changes observed in neuronal types showed a significant loss of dendrites and dendritic spines, especially in the oldest cases. These findings were similar to those previously described in other cerebral areas during aging, but a specific vulnerability of the largest substantia nigra neuronal type could be observed. Nodulations and beaded aspects of dendrites are reminiscent of those changes previously described in MPTP toxicity. Dendritic varicosities found in the oldest cases have also been found in dendrites of large substantia nigra neurons in PD. Cytoskeletal abnormalities have been described in PD but were not found in the present study. Therefore, other pathophysiological mechanisms different from the cytoskeletal compromise occurring in some neurodegenerative diseases should be involved in aging.

Antigenic determinant properties of neurofibrillary tangles. Relevance to progressive supranuclear palsy

Neuronal cytoskeleton is composed of microfilaments, neurofilaments and microtubules which show distinctive ultrastructural characteristics. Different groups of antibodies against neurofilaments and microtubule associated proteins which were grouped according to their specificity for proteins of perykarium, axons and/or dendrites have been produced. A 8.6 kD polypeptide called ubiquitin has been recognized as one of the heat shock proteins. Ubiquitin is implicated in the non-lysosomal degradation of abnormal proteins and other proteolytic intracellular mechanisms. Several immunohistological studies on Alzheimer's disease (AD)-neurofibrillary tangles (NFTs) demonstrated that antibodies for different normal cytoskeletal components bind to NFTs-bearing neurons. AD-NFTs could be also demonstrated using antibodies for the beta-amyloid protein. The production and accumulation of abnormal proteins such as those observed in AD-NFTs induce a ubiquitin-mediated degradative pathway to remove them. It has been demonstrated that ubiquitin is covalently associated with insoluble neurofibrillary material of AD-NFTs. Topographical differences in the distribution of NFTs underscore that different neuronal populations including neocortical neurones are affected in progressive supranuclear palsy (PSP) and AD. Differences in the molecular composition of PSP-NFTs highlighted by immunochemical studies induce us to speculate that different physio- and aetiopathogenetic mechanisms are operative in the production of PSP-NFTs.

Clinico-pathological correlations in meningiomas: a DNA and immunohistochemical study

We have studied 41 meningiomas classified histologically as benign, atypical or anaplastic. There were 26 females and 15 males and the mean age was 53 years. 36 tumours were supratentorial, 4 infratentorial and one spinal. Flow cytometry was performed on paraffin-embedded tissue using a selective staining technique for DNA. The ploidy index of DNA and percentage of cells in the S and G2/M phases were calculated. Results were correlated with clinical, histological and immunohistological data. 16/41 tumours were found to be diploid, 17/41 aneuploid and 8/41 could not be analysed. Significant correlations were found between aneuploid tumours and some qualitative features such as recurrence, pleomorphism, high cellular density, mitotic activity and brain and soft tissue infiltration. A high proliferative index appeared to be associated with clinical aggressiveness. No particular correlation between the expression of cytokeratin and epithelial membrane antigen markers and flow cytometry was found. Our results suggest that DNA flow cytometry in meningiomas may be of value in predicting the behaviour of these neoplasms and confirm that epithelial pattern in meningiomas is not linked to increased anaplasia or poor prognosis.

Neuronal changes in the nigrostriatal pathway of 1-methyl-4-phenylpyridine-treated mice

Thirty young-adult mice were treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) 30 mg/kg/day for 2 days and sacrificed 24 hours later in order to determine striatal catecholamines and to study morphological changes in the nigrostriatal pathway. Immunohistological techniques were also used with polyclonal antibodies for glial fibrillary acidic protein (GFAP) and tyrosine hydroxylase (TH), and monoclonal antibodies for two subunits of neurofilaments. Silver impregnation demonstrated conspicuous neuronal changes affecting cellular processes from substantia nigra in all treated mice. Terminal and axonal degeneration were also observed in striata. These changes were associated with a moderate to marked gliosis. The TH immunoreactivity was normal in cell bodies of substantia nigra but was decreased in striata from MPTP-treated mice. These data indicate that in mice the deterioration of dendritic and axonal neuropil may constitute a significant causal factor of MPTP neurotoxicity.

Epithelial differentiation in gliomas, meningiomas and choroid plexus papillomas

The immunohistological findings using antibodies to different intermediate filaments (glial fibrillary acidic protein, vimentin and two types of cytokeratin) and epithelial membrane antigen are described in 89 gliomas, 19 meningiomas and 8 choroid plexus papillomas (CPPs) from adult patients. All the patients had total or subtotal surgical excision of their tumours with clinical follow up for between 3 and 7 years. The immunohistological results were correlated with the histological features and patient survival. Tumours other than low grade astrocytomas, oligodendrogliomas and anaplastic ependymomas expressed one or more epithelial markers. This immunohistological evidence of epithelial differentiation in the absence of histological epithelial features in gliomas confirms that the two are not necessarily correlated. It is concluded that the expression of epithelial markers in some intradural tumours may reflect aberrant differentiation related to the degree of anaplasia in poorly differentiated astrocytomas and glioblastomas. All the patients with anaplastic epithelial marker-positive gliomas died within 1 year, whereas only 68% of patients with marker-negative tumours died within the follow-up period. In ependymomas and meningiomas, the expression of epithelial markers may reflect their histogenesis, while in malignant CPPs such expression could denote either their aberrant differentiation or histogenetic derivation.

Immunohistological signposts in central nervous system tumours with neuronal differentiation

25 neuronal tumours with a panel of antibodies were studied and it was found that vimentin was present in 15 tumours. It was also found in a few cells within rosettes. PGP 9.5 showed a somatic pattern of staining with nuclear and perinuclear positivity in 23. Neurofilament reactivity was found in 14. Retinal S-antigen was detected only in one medulloblastoma, 3/4 pineal tumours and 2/2 retinoblastomas. Reactivity, for synaptophysin was present in 2/5 medulloblastomas, 3/10 neuroblastomas and 2/2 retinoblastomas. GFAP was demonstrated in scattered tumour cells in 4/5 medulloblastomas. Two of these were the only tumours featuring bipolar differentiation whilst it was unipolar in the remainder. The significance of these findings in relation to the ontogeny of these tumours is discussed.

Differentiation in embryonal neuroepithelial tumors of the central nervous system

Ninety-six embryonal neuroectodermal tumors were studied histologically and immunohistologically with a panel of antibodies including glial, neuronal, epithelial, mesodermal, and myelin markers. In 71 tumors there was glial and neuronal differentiation and expression both of an S (photoreceptor) antigen and vimentin. In five tumors there was only glial differentiation and in 20 tumors only neuronal differentiation. No reactivity for myelin and epithelial markers was found. Histologic and immunohistologic findings identified various degrees of differentiation in different tumors, which was bipolar (glial and neuronal) in most tumors and unipolar in the remainder. The authors suggest that their findings may be the result of normal or aberrant oncogenic differentiation, agreeing with the nomenclature of the World Health Organization classification for these tumors with and the inclusion of a category for ependymoblastoma.

Haemangioblastoma: histological and immunohistological study of an enigmatic cerebellar tumour

Paraffin-embedded blocks of 36 cerebellar haemangioblastomas were reacted with a panel of antibodies including glial fibrillary acidic protein, vimentin, epithelial membrane antigen, cytokeratin, Factor VIII, a neuroendocrine marker and with Ulex europaeus. agglutinin The main histological features, apart from the characteristic large abnormal vessels, were a prominent reticulin network, a cystic architecture and cellular and nuclear polymorphism. Two cell types were identified: endothelial and stromal. Twenty tumours were positive for glial fibrillary acidic protein because of included or reactive astrocytes as well as positive stromal cells. Vimentin was positive in all tumours with a diffuse distribution and a somatic pattern; blood vessels, stromal cells and reactive astrocytes were strongly positive. Factor VIII and Ulex europaeus agglutinin reactivity were present in a similar pattern of staining in endothelium and in five cases there were stromal cells that were positive with the latter. We were not able to ascertain the histogenesis of the stromal cell, which remains enigmatic.

The value of conjunctival biopsy in childhood cystinosis

Cystinosis is frequently presented with cystine storage in the cornea and conjunctiva, and the diagnosis can be established by slit-lamp examination. It can also be confirmed by electron microscopy of a conjunctival biopsy. The present paper reports on a 16-month-old boy with Fanconi's syndrome, in whom the slit-lamp examination did not show crystal deposits of cystine in the conjunctiva. The ultrastructural study of the conjunctival biopsy demonstrated polygonal crystals within double membrane-limited organelles located in fibroblasts. Similar crystals were subsequently found in a kidney biopsy. We therefore think that conjunctival biopsy is a valuable diagnostic tool prior to performing renal biopsy, even in cases with negative findings by ophthalmologic examination.