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Aims: There is evidence that accumulation of α‐synuclein (α‐syn) in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) results from impaired removal of α‐syn rather than its overproduction. Kallikrein‐6 (KLK6), calpain‐1 (CAPN1) and cathepsin‐D (CTSD) are among a small number of proteases that cleave α‐syn and are dysregulated in PD and DLB. Our aim in this study was to determine whether protease activity is altered in another α‐synucleinopathy, multiple system atrophy (MSA), and might thereby modulate the regional distribution of α‐syn accumulation. Methods: mRNA and protein level and/or activity of KLK6, CAPN1 and CTSD were measured and assessed in relation to α‐syn load in multiple brain regions (posterior frontal cortex, caudate nucleus, putamen, occipital cortex, pontine base and cerebellar white matter), in MSA (n = 20) and age‐matched postmortem control tissue (n = 20). Results: CTSD activity was elevated in MSA in the pontine base and cerebellar white matter. KLK6 and CAPN1 levels were elevated in MSA in the putamen and cerebellar white matter. However, the activity or level of these proteolytic enzymes did not correlate with the regional distribution of α‐syn. Conclusions: Accumulation of α‐syn in MSA is not due to reduced activity of the proteases we have studied. We suggest that their upregulation is likely to be a compensatory response to increased α‐syn in MSA. [ABSTRACT FROM AUTHOR]

The relative amounts of amyloid β-protein (Aβ) in cerebral blood vessels and parenchyma vary considerably amongst patients with Alzheimer's disease (AD). Although several mechanisms have been proposed to explain this variability, the underlying genetic and environmental determinants are still unclear, as are the functional consequences. Polymorphisms in APOE , the gene for apolipoprotein E (ApoE), influence the risk of developing AD and of deposition of Aβ within the brain. We examined the relationship between the APOE genotype and the relative extent of accumulation of Aβ as plaques within the cerebral parenchyma and in cortical blood vessels in the form of cerebral amyloid angiopathy (CAA), in autopsy brain tissue from 125 AD cases and from 53 elderly, neurologically normal controls of which 19 had CAA without other neuropathological features of AD. In the AD cases, we also assessed whether the severity of CAA was related to the age of onset and duration of dementia, risk factors for atherosclerotic vascular disease, and histologically demonstrable cerebral in-farcts or foci of haemorrhage. The APOE genotype was determined by a standard polymerase chain reaction-based method. Paraffin sections of frontal, temporal and parietal lobes were immunolabelled for Aβ and the parenchymal Aβ load (total Aβ minus vessel-associated Aβ) was quantified by computer-assisted image analysis. CAA severity was scored for cortical and leptomeningeal vessels. The relevant clinical data were obtained from the database of the South West Brain Bank. In AD, we found the severity of CAA to be strongly associated with the number of ℇ4 alleles (P < 0.0001) but the parenchymal Aβ load to be independent of APOE genotype. Cases with severe CAA had a lower parenchymal Aβ load than had those with moderate CAA (P = 0.003). Neither the severity of CAA nor the parenchymal Aβ load correlated with age of onset, duration of disease or age at death, and the severity of CAA also did not correlate with the presence of cerebral infarcts or foci of haemorrhage. These findings indicate that possession of the APOE ℇ4 allele favours vascular over parenchymal accumulation of Aβ in AD. This may influence the pathogenesis of neurodegeneration in ℇ4-associated AD. [ABSTRACT FROM AUTHOR]

The mechanism of neuronal death in brain ischaemia remains unclear. Morphology, terminal transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) and immunohistochemistry for the pro-apoptotic enzyme caspase-3 (CASP3), for its substrates poly(ADP-ribose) polymerase (PARP) and the DNA-dependent protein kinase catalytic subunit (DNA–PKCS) and for poly(ADP-ribose) (PAR), an end-product of PARP activity, were used to investigate neuronal death in brain infarcts from 15 men and 20 women, aged 46–95 years. The infarcts varied in age from 18 h to several months. Neuronal death was characterized morphologically by cell shrinkage, cytoplasmic hypereosinophilia and moderate nuclear pyknosis with later chromatin dispersal and disintegration, but not features of apoptosis. Occasional apoptotic bodies were seen but these appeared to be related to inflammatory cells, endothelial cells and occasional glia, including satellite cells. Neurones within infarcts showed strong nuclear and cytoplasmic labelling for CASP3 during the first 2 days after infarction. Neuronal DNA–PKCS, PARP and poly(ADP-ribose) immunoreactivity was demonstrable in scattered neurones in and adjacent to infarcts for 18–24 h but thereafter declined to below detectable levels in most cases. TUNEL labelled cells towards the edge of the infarcts, particularly at 2–4 days, but most of the labelling could be prevented by preincubation of the sections in diethyl pyrocarbonate to inactivate endogenous nucleases. Between 3 days and 3 weeks, CASP3 and DNA–PKCS were detected in proliferating capillaries and CASP3, PARP and poly(ADP-ribose) in infiltrating macrophages. Our findings indicate that neuronal death in human brain infarcts has some of the early biochemical features of programmed cell death, with upregulation of CASP3 and rapid disappearance of DNA–PKCS and PARP. However, the morphological changes are not those of apoptosis, the DNA cleavage occurs relatively late, and some of the TUNEL is probably mediated by the release of endogenous endonucleases during protease or microwave pretreatment of the damaged tissue. [ABSTRACT FROM AUTHOR]

Introduction: Mos, the product of the C-mos gene, is a component of the mitogen-activated protein-kinase transduction pathway, and is involved in the control of meiosis and mitosis. High levels have been reported to cause p53-mediated growth arrest and apoptosis. Apart from a study on lung carcinomas, there is little information about its role in human neoplasia. The aim of this study was to investigate expression of mos in astrocytic tumours and to correlate it with the accumulation of p53. Material and methods: We studied the expression of mos in 62 cases of supratentorial diffuse astrocytic tumours and correlated this with tumour grade, survival and accumulation of p53. Results: Intracytoplasmic immunopositivity for mos was found in 28 (45%) cases: 3/20 (15%) grade 2 astrocytomas, 9/20 (45%) grade 3 anaplastic astrocytomas and 16/22 (73%) glioblastomas. Immunopositivity for mos correlated significantly (P < 0.01) with tumour grade but not with p53 expression. In contrast to the findings in relation to lung carcinomas, immunopositivity for mos in astrocytic tumours did not predict recurrence-free or overall survival time. Cytoplasmic immunostaining was observed in scattered large cortical neurons adjacent to tumours, possibly as a result of ‘stress’-induced abortive entry into the cell cycle. Conclusions: The correlation of mos immunopositivity with tumour grade may reflect the expansion of more malignant mos-positive clones. This study provides evidence that mos may be involved in the neoplastic progression of a proportion of astrocytic tumours. [ABSTRACT FROM AUTHOR]

Introduction: Glioblastomas have a median survival of 9–12 months. However, some patients die within a few weeks of diagnosis and others may survive for 2 years or more. To try to predict survival more accurately, we have evaluated a number of morphological, immunohistochemical and molecular markers in a retrospective series of glioblastomas. Material and methods: Paraffin sections from 107 consecutive glioblastomas diagnosed between 1993 and 1997 were included in the study. All cases were reviewed and the presence of calcification or oligodendroglioma-like areas noted. Sections were immunostained with commercial antibodies to retinoblastoma and DCC proteins and subjected to in situ hybridization with probes to chromosomes 12 and 10. Results: Loss of retinoblastoma and DCC protein expression was seen in 20% and 71% of glioblastomas respectively. Loss of retinoblastoma protein expression correlated with poor outcome (P = 0.045). 64% of glioblastomas showed loss of chromosome 10 but this did not have a significant association with survival. The five tumours with oligodendroglioma-like areas had a median survival of 70 weeks, compared with 27 weeks for those without (P = 0.014). Conclusion: In this study, age, loss of retinoblastoma protein and a lack of oligodendroglioma-like areas were predictors of significantly shorter survival in glioblastomas. [ABSTRACT FROM AUTHOR]

Introduction: Post-haemorrhagic ventricular dilatation (Phvd) complicates 30% of cases of severe intraventricular haemorrhage (Ivh) in preterm infants. The majority require shunt surgery and are disabled. The mechanism by which Ivh leads to Phvd is not understood, and no satisfactory neonatal model exists. We have developed a neonatal rat model of Phvd to study the mechanisms of Phvd. Methods: Mixed sex, 7-day-old (P7) Wistar rats were anaesthetized with halothane and placed in a stereotactic frame. Ivh was simulated by injection of citrated rat blood into alternate lateral ventricles on two consecutive days (P7, P8). Survivors were killed on P22 and their brains fixed by immersion in 4% formaldehyde. H&E-stained 5 µm sections were examined for pathological changes. Glial reaction was assessed by immunohistochemistry for glial fibrillary acidic protein, and ventricular area in standard coronal planes through the cerebrum was measured using Nih Image software. Results: Increased ventricular size, focal ependymal disruption, reactive changes and accumulation of haemosiderin in scattered parenchymal cells were observed in 30% of the experimental animals. Injection of blood also caused a narrow zone of dense periventricular gliosis. Conclusion: This rat pup model of Phvd may be useful for ascertaining the mechanism of post-haemorrhagic ventricular dilatation. [ABSTRACT FROM AUTHOR]