How do cognitive and axial motor signs correlate in Parkinson's disease? A 6-year prospective study.

Impairment of Parkinson's disease (PD) axial motor signs (AMS) has been described as a risk factor for dementia. Executive dysfunction is an important feature in recently proposed clinical diagnostic criteria for PD dementia. To clarify the relationship between AMS progression and executive cognitive performance, we conducted a 6-year prospective study in PD patients without AMS impairment at baseline. A hospital-based cohort of PD patients (n = 24) without dementia, in the initial motor stage (Hoehn-Yahr < or = 2), and matched controls (n = 20) were followed prospectively over a 6-year period. Neuropsychological tests were performed in both groups, and motor function (including AMS: speech, gait, postural instability) was evaluated in the PD group. The PD group had a significantly higher decline in neuropsychological test scores than did the controls. Most of the neuropsychological and motor decline occurred in the last 4 years. In UPDRS III, progression of AMS and especially speech were the most important motor variables related to dementia. There was a correlation between speech impairment progression and declines in MMSE (r = -0.598, p = 0.002), Clock Drawing (r = -0.671, p < 0.001), Semantic Verbal Fluency (r = -0.435, p = 0.034), Alternating Sequences (r = 0.497, p = 0.014), and Raven's Coloured Progressive Matrices (r = -0.735, p < 0.001). PD patients with higher speech impairment progression showed more rapid declines in some neuropsychological tests. Further studies are needed to clarify the different roles of speech, gait and postural instability on the initial phases of cognitive dysfunction.

Plasma acrolein levels and their association with delayed ischemic neurological deficits following aneurysmal subarachnoid haemorrhage: a pilot study.

BACKGROUND: The molecular mechanisms of cerebral vasospasm following aneurysmal subarachnoid haemorrhage (aSAH) remain unclear. Acrolein, a reactive metabolite produced in many models of mechanical and ischemic injury, has been shown to cause vasospasm in coronary artery and aorta models. These traits suggest it may play a role in post-aSAH cerebral vasospasm. This pilot study was designed as a preliminary investigation to determine if acrolein levels could be used as a clinical tool to predict the presence of vasospasm. METHODS: Eleven patients with aSAH and Hunt and Hess admission grades of III-V were prospectively enrolled. Patients were stratified according to the presence or absence of vasospasm, defined as a delayed ischaemic neurological deficit in which all other possible causes have been excluded. Soluble acrolein levels were determined at two times points: early (day 1-3 post-SAH) and late (day 8-12 post-SAH) and the change in acrolein levels over this period was computed using a Mann-Whitney test. RESULTS: The change in acrolein levels over this period between the vasospasm and non-vasospasm group trended toward but did not achieve statistical significance (means: 5.68 versus -5.54; medians: 5.27 versus -3.99; range: -8.067 to 22.904 versus -13.83 to 5.199 p=0.13). Five out of six vasospasm patients showed an increase in acrolein levels over the vasospasm period. Three out of four non-vasospasm patients showed a decrease over the vasospasm period. CONCLUSIONS: The results of this pilot study suggest that acrolein levels increase in patients undergoing vasospasm during the vasospasm window. This suggests that acrolein may play a role in the pathways leading up to or following vasospasm. There is a need for larger more definitive studies.

Elevation of monocyte chemoattractant protein-1 in patients experiencing neurocognitive decline following carotid endarterectomy.

BACKGROUND: Previous studies have demonstrated that elevated pre-operative monocyte count is an independent predictor of acute neurocognitive decline following carotid endarterectomy (CEA). Monocyte chemoattractant protein-1 (MCP-1), secreted by human endothelial and monocyte-like cells, is a potent mediator of inflammation and mononuclear cell trafficking. This study examines the relationship between peri-operative serum MCP-1 elevation and post-operative neurocognitive injury following CEA. METHODS: Fifty-two patients undergoing CEA and 67 lumbar laminectomy (LL) controls were administered a battery of five neuropsychological tests pre-operatively and on post-operative day 1 (POD 1). Change in individual test scores from baseline to POD 1 were converted into Z-score and used to develop a point system quantifying the degree of neurocognitive dysfunction relative to change within the LL group. Neurocognitive injury following CEA was defined as a score greater than 2 standard deviations above mean total deficit scores of LL controls. Serum MCP-1 levels were measured pre-operatively and on POD 1 by enzyme-linked immunosorbent assay. FINDINGS: Mean percent MCP-1 elevation was higher for the 13 injured CEA patients (147.7 +/- 32.4%) in our cohort compared to 39 age- and sex-matched uninjured CEA patients (76.0 +/- 16.5%). In unconditional multivariate logistic regression analysis, percent elevation in serum MCP-1 level was associated with neurocognitive injury one day after CEA (OR = 2.19, 95% CI = 1.13-4.26, P = 0.021, for a 100% elevation from pre-operative levels). CONCLUSIONS: Peri-operative elevations in serum MCP-1 levels correlate with acute neurocognitive dysfunction following CEA. These data implicate an inflammatory mechanism in the pathogenesis of Ischaemic neurocognitive decline.

Does timing and dosage of levodopa modify drug-induced dyskinesias and motor fluctuations? A retrospective analysis.

The aim of this study was to verify the influence of levodopa treatment in the development of long-term complications of Parkinson's disease (PD). We retrospectively analysed several epidemiological characteristics of the disease including long-term motor complications with timing and dose of levodopa in 50 patients. No differences between timing and initial dosage of levodopa were observed in patients who developed dyskinesias or motor fluctuations and those who did not. The patients who developed dyskinesias were younger and the rate of decline was faster in patients who developed motor fluctuations. These results suggest that late complications of levodopa are independent of the timing and initial dosage.

Influenza virus-infected dendritic cells stimulate strong proliferative and cytolytic responses from human CD8+ T cells.

Antigen-specific, CD8+, cytolytic T lymphocytes (CTLs) could potentially provide resistance to several infectious and malignant diseases. However, the cellular requirements for the generation of specific CTLs in human lymphocyte cultures are not well defined, and repetitive stimulation with antigen is often required. We find that strong CD8+ CTL responses to influenza virus can be generated from freshly isolated blood T cells, as long as dendritic cells are used as antigen presenting cells (APCs). Small numbers of dendritic cells (APC:T cell ratio of 1:50-1:100) induce these CTL responses from most donors in 7 d of culture, but monocytes are weak or inactive. Whereas both dendritic cells and monocytes are infected with influenza virus, the former serve as effective APCs for the induction of CD8+ T cells while the latter act as targets for the CTLs that are induced. The strong CD8+ response to influenza virus-infected dendritic cells is accompanied by extensive proliferation of the CD8+ T cells, but the response can develop in the apparent absence of CD4+ helpers or exogenous lymphokines. CD4+ influenza virus-specific CTLs can also be induced by dendritic cells, but the cultures initially must be depleted of CD8+ cells. These findings should make it possible to use dendritic cells to generate human, antigen-specific, CD8+ CTLs to other targets. The results illustrate the principle that efficient T cell-mediated responses develop in two stages: an afferent limb in which dendritic cells are specialized APCs and an efferent limb in which the primed T cells carry out an immune response to many types of presenting cells.

Role of p67-phox SH3 domains in assembly of the NADPH oxidase system.

Src homology 3 (SH3) domains direct cellular localization and signal transduction through specific protein-protein interactions with proline-rich target sequences. The two SH3 domain in p67-phox, a cytosolic component of the phagocyte NADPH oxidase system, may mediate interactions within the oxidase complex and direct its translocation to membranes. The requirement for SH3 domains in p67-phox was studied both in cell-free and whole cell oxidase assay systems. The amino-terminal domain of p67-phox (amino acids 1-246) that lacks both SH3 domains was active in vitro. Various forms of p67-phox lacking one or both SH3 domains were produced in whole cells using episomal expression vectors to stably transfect p67-phox-deficient Epstein-Barr virus-B cells derived from chronic granulomatous disease patients. Complete restoration of NADPH oxidase activity was achieved with full-length p67-phox cDNA expression. Deletion of either SH3 domain resulted in dramatic reductions of NADPH oxidase activity relative to corrected transfected cells, which correlated with decreases in membrane binding. Deletion of both SH3 domains completely abolished p67-phox membrane binding and oxidase activity. Thus, in contrast to oxidase reconstitution in a cell-free system, we observed a requirement for both SH3 motifs for restoration of oxidase activity and binding of p67-phox to membranes.

Identification of a thermolabile component of the human neutrophil NADPH oxidase. A model for chronic granulomatous disease caused by deficiency of the p67-phox cytosolic component.

Mild heating of human neutrophils inactivates the respiratory burst oxidase, producing a defect in superoxide production and bacterial killing comparable to that seen in patients afflicted with chronic granulomatous disease (CGD). We have now investigated the mechanism and specificity of this inactivation by examining the effect of mild heating on the known oxidase components: the membrane-bound subunits of the cytochrome b558 (gp91-phox and p22-phox) and the two cytosolic oxidase factors (p47-phox and p67-phox). Heating (46 degrees C for 7.5 min) caused intact neutrophils to lose greater than 85% of their capacity to produce superoxide, a defect which was localized to the cytosolic, but not the membrane, fraction. Complementation studies with CGD cytosols deficient in either p47-phox or p67-phox suggested that the defective component of heat-inactivated cytosol was p67-phox. This was confirmed by experiments showing that recombinant p67-phox, but not p47-phox, exhibited lability at 46 degrees C and completely reconstituted oxidase activity of heat-treated cytosol. These studies indicate that mild heating of either intact neutrophils or normal neutrophil cytosol results in a selective inactivation of p67-phox, providing a model oxidase system for the extremely rare p67-phox-deficient form of CGD.

Increased cerebrospinal fluid dopamine and 3,4-dihydroxyphenylacetic acid levels in Huntington's disease: evidence for an overactive dopaminergic brain transmission.

Levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), noradrenaline (NA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) in the CSF of patients with Huntington's disease (HD) were measured by HPLC. CSF DA, DOPAC, and MHPG levels were found to be increased in HD patients. Levels of HVA, 5-HIAA, and NA in the CSF of HD patients did not differ from those of controls. Changes in CSF DA and DOPAC levels were consistent with previous findings of increased DA tissue content in some brain areas of patients with HD. These results suggest that CSF DOPAC levels could be a more reliable index of overactive dopaminergic brain systems in HD than CSF HVA levels.

Characterization of neutrophil NADPH oxidase factors p47-phox and p67-phox from recombinant baculoviruses.

Superoxide production by phagocytic blood cells involves assembly of an active NADPH oxidase complex from components found both in membrane and cytosolic locations in resting cells. We recently cloned cDNAs encoding two cytosolic components (p47-phox and p67-phox) of the oxidase that are deficient in distinct forms of autosomal recessive chronic granulomatous disease. The precise roles of p47-phox and p67-phox were explored further using purified factors produced in large quantities using recombinant baculoviruses to infect cultured Sf9 insect cells. Neither p47-phox nor p67-phox are thought to represent the flavoprotein components of the oxidase, since neither of the purified recombinant factors contained or bound FAD. Recombinant p47-phox and p67-phox are capable of restoring the deficient cytosol from chronic granulomatous disease patient neutrophils to nearly normal levels in a cell-free reconstitution system. Both p47-phox and p67-phox, used together in the absence of neutrophil cytosol, are incapable of supporting cell free production of superoxide, confirming the involvement of other soluble factor(s) in the assembly of an active oxidase in vitro.

Overflow of endogenous dopamine and 3,4-dihydroxyphenylacetic acid from tissues of the rat brain, elicited by electrical stimulation, depolarization by potassium and activation of carrier-mediated release.

Overflow of dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) from slices of striatum and slices containing the nucleus accumbens of the rat, during spontaneous loss and as elicited by electrical stimulation, depolarization by potassium and carrier-mediated release, in conditions of inhibition of COMT was studied. Levels of dopamine and DOPAC in tissues and in the superfusates were quantified by means of high pressure liquid chromatography with electrochemical detection (HPLC-ECD). Inhibition of neuronal uptake by cocaine (10 mumol/l) or GBR 12909 (100 nmol/l) was found to increase only the spontaneous outflow of dopamine. Electrical stimulation of slices of striatum produced an increase in levels of overflow of dopamine, but not of DOPAC. Inhibition of neuronal uptake during electrical stimulation potentiated the release of dopamine and slightly reduced levels of DOPAC in the effluent. Changes in the electrically-stimulated or potassium-evoked release of dopamine, as a result of blockade or activation of prejunctional dopamine receptors, did not affect levels of DOPAC in the effluent. Release of dopamine, induced through a favourable sodium gradient, was not accompanied by an increased release of DOPAC. The results presented demonstrate that most of the DOPAC does not originate from a recently released pool of dopamine.

Role of type A and B monoamine oxidase on the formation of 3,4-dihydroxyphenylacetic acid (DOPAC) in tissues from the brain of the rat.

The role of monamine oxidase (MAO), type A and B, on the deamination of dopamine in the striatum, nucleus accumbens and frontal cortex of the rat was studied. Levels of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) tissue were quantified by means of high pressure liquid chromatography with electrochemical detection. Rats were given pargyline (75 mg/kg), selegyline (5 mg/kg) or clorgyline (2 mg/kg) by the intraperitoneal route, 60 min before sacrifice; in another set of experiments, clorgyline (2 mg/kg, i.p.) was given 15 or 30 min before sacrifice. Only clorgyline and pargyline were found to reduce significantly the formation of DOPAC and HVA in all the three areas of brain under study (83-97% reduction). The inhibition of deamination of dopamine by clorgyline and pargyline was accompanied by an increase in levels of dopamine in tissue. The increase of the levels of amine in tissue, as a result of inhibition of MAOA was more marked in the frontal cortex (52% increase) and the accumbens (39% increase), than in the striatum (25% increase). The results suggest that a substantial amount of DOPAC in brain derives from the deamination of dopamine by MAOA.

A kinetic study of the rate of formation of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the brain of the rat: implications for the origin of DOPAC.

The rates of disappearance of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the brain of rats treated with the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine were measured. Levels of dopamine. DOPAC and HVA in tissue were quantified in the striatum, nucleus accumbens and frontal cortex of the rat by means of high pressure liquid chromatography with electrochemical detection. Rats were sacrificed 1, 2 or 3 hr after the administration of alpha-methyl-p-tyrosine (200 mg/kg, i.p.). Levels of dopamine, DOPAC and HVA in tissue were logarithmically transformed, plotted against the duration of inhibition of tyrosine hydroxylase and the rate constant of the decline of dopamine and of its metabolites calculated. The rate constant of decline of DOPAC in each of brain studied was found to be greater than that for dopamine. The rate constant for the decline of dopamine was found to be greater in areas of the brain presenting the largest DOPAC/dopamine tissue ratios (frontal cortex greater than nucleus accumbens greater than striatum). The present results suggest that a substantial amount of DOPAC in brain derives from a newly formed pool of dopamine.