Gelatinase B, PECAM-1 and MCP-3 gene polymorphisms in Belgian multiple sclerosis

Polymorphic microsatellite markers in the genes for gelatinase B, PECAM-1 and MCP-3 have previously been analysed in Swedish and Sardinian individuals to test for association with multiple sclerosis (MS). Confirmation and comparison of genetic associations in various ethnic populations is mandatory and, therefore, we studied these three gene polymorphisms in 216 clinically definite MS patients and 193 normal controls, and in 148 simplex MS families, all of Belgian origin. No allelic associations were found between MS and the CA microsatellite marker in the promoter region of the gelatinase B gene, and the polymorphic CA repeat in the sixth intron of PECAM1. However, the two most abundant alleles of the CA/GA microsatellite polymorphism in the promoter-enhancer region of the MCP-3 gene, A2 (109 bp) and A3 (111 bp), were found to be significantly associated with disease in the case-control study [OR (95% CI)=0.68 (0.51-0.92), p (1 df)=0.015 and OR (95% CI)=1.62 (1.22-2.14), p (1 df)=0.0010, respectively], but not in the family study. These results are in agreement with previous findings in the Swedish and Sardinian populations and reinforce the possibility of a role for chemokines in MS pathogenesis.

[Blood pressure monitoring: dangers and traps]

The measure of blood pressure is probably the the most frequently performed medical act, and the less reliable. The introduction of non invasive recording of ambulatory blood pressure allowed to better define the white coat effect, that is the effect of the presence of a doctor on the blood pressure. White coat hypertension is defined as an abnormal blood pressure in the office and a strictly normal blood pressure outside the medical environment. As such, white coat hypertension is not associated with an increase of cardiovascular morbidity and mortality and thus does not justify drug therapy. However, one third of the patients will progress with time to more severe stages of hypertension.

The neural system that bridges reward and cognition in humans: an fMRI study

We test the hypothesis that motivational and cognitive processes are linked by a specific neural system to reach maximal efficiency. We studied six normal subjects performing a working memory paradigm (n-back tasks) associated with different levels of monetary reward during an fMRI session. The study showed specific brain activation in relation with changes in both the cognitive loading and the reward associated with task performance. First, the working memory tasks activated a network including the dorsolateral prefrontal cortex [Brodmann area (BA) 9/46] and, in addition, in the lateral frontopolar areas (BA 10), but only in the more demanding condition (3-back task). This result suggests that lateral prefrontal areas are organized in a caudo-rostral continuum in relation with the increase in executive requirement. Second, reward induces an increased activation in the areas already activated by working memory processing and in a supplementary region, the medial frontal pole (BA 10), regardless of the level of cognitive processing. It is postulated that the latter region plays a specific role in monitoring the reward value of ongoing cognitive processes. Third, we detected areas where the signal decreases (ventral-BA 11/47 and subgenual prefrontal cortices) in relation with both the increase of cognitive demand and the reward. The deactivation may represent an emotional gating aimed at inhibiting adverse emotional signals to maximize the level of performance. Taken together, these results suggest a balance between increasing activity in cortical cognitive areas and decreasing activity in the limbic and paralimbic structures during ongoing higher cognitive processing.

[Alzheimer's disease: a public health problem: yes, but a priority?]

Alzheimer's Disease is a major Public Health problem for many reasons. First, it is a frequent disease since, in France, the prevalence was estimated at about 400.000 cases, and the annual incidence at 100.000 cases. The frequency of the disease increases, in particular due to the ageing of the population. This disease has major consequences on the life of the patient and his/her caretaker. The cost of the disease is important, estimated at about 50 milliards of French francs. Pharmaceutical treatment and other interventions are possible in particular to delay the nursing home placement. On the other hand, this disease is often ignored, under-diagnosed, underestimated and exposed to inequality in resorting to care. In summary, Alzheimer's Disease (AD) has all the criteria required for a major public health problem. In spite of this observation, AD is not yet considered as a priority for health authorities, although attitudes are changing.

Forced collectionism after orbitofrontal damage

A collector is a person who collects things on purpose, either as a hobby or business, or for personal satisfaction, e.g., stamp, coin, or art collector. In such instances, the act of collecting things represents voluntary, controlled, goal-directed, selective searching. Pathologic patterns of collecting have been observed following brain damage, particularly frontal lobe damage, ranging from a tendency to grasp (prehension behavior) to an irrepressible need to seize surrounding objects and store them (hoarding behavior). These adnormal behaviors express an excessive adherence to environmental stimuli but in no way express a planned process directed toward specific items. In this article, we describe an unusual pattern of pathologic collecting behavior due to frontal lobe damage: involuntary irrepressible collecting that is goal-directed and selective. The authors report a patient who collected specifically household electrical appliances following a bilateral damage of orbito- and polar-prefrontal cortex. The patient had involuntary irrepressible collecting that was goal-directed and selective. This "forced collectionism" is different from that of the usual collectionism encountered in patients with frontal lobe lesions, as the latter is in no way a planned process directed toward specific items.

The immunological basis of current and novel therapies of multiple sclerosis

The etiology and the pathogenesis of multiple sclerosis are not yet known. There might be a role for genetic susceptibility, for environmental factors and for inflammatory and immunological changes. Most of the actual therapies are based on the latter two phenomena. We review here corticosteroids, interferon beta and copolymer 1 as the current drugs of choice and compare schematically the immunological basis of the mechanisms of action of these three substances with those of experimental or other treatments.

[Validation of the French language version of the Parkinson's Disease Questionnaire - PDQ-39]

After Alzheimer's disease, Parkinson's disease (PD) is the second most frequent degenerative disease of the central nervous system. The consequences of PD at the functional, social and emotional levels warrant a better understanding the patient's perceptions as measured using a specific instrument rather than restricting the medical approach to the clinical evaluation of the motor component. In 1996, we began implementation of a project to transculturally validate the single specific instrument that had been published and was available at that time: PDQ-39. The scale consists in a 39-item questionnaire enabling determination of an overall quality-of-life score and scores for 8 specific dimensions: mobility, activities of daily living, emotional well-being, stigma, social support, cognitions, communication and bodily discomfort. Eighty-nine patients taking part in an open-label study of the safety of a combination of pergolide and dopa therapy were included and followed up on D15 and after 8 weeks. The process of "Forward-Backward" translation, conducted in close liaison with the authors, enabled semantic and linguistic validation of the French language version. The content was validated by PD experts. At baseline, the patients presented quality-of-life scores that were particularly impaired for the dimensions exploring Mobility, Emotional well-being and Bodily discomfort. The main metric properties of the scale were confirmed. The PDQ-39 scores were closely correlated with the related concepts investigated by generic scale, SF-36. The PDQ-39 scores were correlated with the "Mental and Mood Status", "Everyday Activities" and "Motor Status" dimensions determined by the UPDRS. The reliability, expressed by Cronbach coefficients alpha, showed strong consistency of the instrument, very similar to the data for the original version. In contrast to what was observed with SF-36, the scale was particularly sensitive to clinical changes. The initial results make PDQ-39 a precious tool for the optimization of management of patients presenting with PD.

[Hemolytic uremic syndrome and thrombotic thrombocytopenic purpura]

Hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are thrombotic microangiopathies (TMA). Both familial and sporadic forms exist: anaemia, thrombopaenia, renal failure and neurologic disorders are common clinical features. The differential diagnosis depends on plasma levels of von Willebrand factor-cleaving protease: there is a deficiency of this protease in patients with TTP whereas its rate is normal in HUS. We remind pathophysiology, etiologies and treatment of these TMA.

Measles virus exploits dendritic cells to suppress CD4+ T-cell proliferation via expression of surface viral glycoproteins independently of T-cell trans-infection

Dendritic cells (DC) have been proposed to play a pivotal role in transient immune suppression induced by measles virus (MV) infection. In the present study, we show that DC-induced suppression of T-cell proliferation was not mediated by IL-10 or IFNalpha/beta, which are released following infection of DC, but required cell contacts between MV-infected DC and T cells. Human sera containing neutralizing anti-MV antibodies, as well as anti-MV hemagglutinin (HA) or fusion protein (F) mAbs, were found (i) to reverse suppression and (ii) to restore DC allostimulatory capacity. Interestingly, DC-induced T-cell suppression was associated with both phenotypic and functional DC maturation, as demonstrated by IL-12 production and chemotaxis to MIP-3beta. These data suggest that MV infection turns on the maturation program of DC allowing migration to draining lymph nodes, where potent T-cell immune suppression might be achieved via cell surface expression of HA and F glycoproteins, independently of T cell trans-infection.

Is the HM story only a "remote memory"? Some facts about hippocampus and memory in humans

In this review, we argue that a number of current data support the notion that the hippocampal formations play an important role in episodic memory in humans. We will focus on data gathered from three topics within this field: (1) the neuropsychological study of memory in degenerative diseases, which provides striking dissociations of processes, as a function of the location of cerebral lesions and of their functional consequences; (2) the description of patients' memory difficulties after unilateral medial temporal lobectomy. Given the visuo-verbal dissociation, we may anticipate that the study of the effects of such lesions may help in the understanding of the role of the hippocampus in memory, in terms of: (i) the stage of memory processing where the hippocampus is really involved (encoding, consolidation and/or retrieval); (ii) the specificity of the impairments as a function of the nature (verbal vs. visuo-spatial) of the to-be-remembered material; (3) recent evidence from imaging studies: (i) the morphological approach, which provides interesting information with the study of correlations between the volumes of diverse cerebral regions-particularly the volume of the hippocampus-and episodic memory performance and other cognitive measures; (ii) metabolic studies, using PET scan, which were first designed for correlational analyses between performance in episodic memory tasks and glucose utilization at rest in diverse regions of interest, such as the hippocampal formations; (iii) activation studies with PET and functional MRI, which are actually more straightforward, since they allow correlations between the metabolism in regions of interest and performance on line (e.g. during encoding or retrieval of information). In our view, inasmuch as such different approaches-degenerative diseases, lesions or imagery-provide convergent information, they give renewed weight to the notion according to which the hippocampal formations are critically concerned in episodic memory processes.

[Procedural learning and Parkinson disease: implication of striato-frontal loops]

OBJECTIVE

To investigate procedural learning in non demented patients with idiopathic Parkinson's disease (PD).

BACKGROUND

Experimental evidence implicate the basal ganglia in procedural learning. Selective impairment has more recently been described in patients with frontal lesions.

METHODS

The performance of 20 demented patients and 15 matched normal controls was studied in the serial reaction time task (SRTT). Performance on procedural task was further compared with that of 9 normal controls and with patients' performance on tests assessing explicit memory, executive functions and global efficiency.

RESULTS

The group of patients with PD showed impaired procedural learning. The difference of response time between the repeated and the non-repeated blocks was smaller in PD when compared to controls. Subsequent analyses separated PD patients into two subgroups according to their performance on SRTT, measured by the rebound effect. PD patients whose learning was normal differed from PD patients whose learning was impaired on performance in tests sensitive to frontal lobe dysfunction.

CONCLUSION

These results confirm the implication of the striatum in procedural learning and suggest that performance on cognitive procedural learning depends on the striato-frontal circuits.

Flagellin stimulation of intestinal epithelial cells triggers CCL20-mediated migration of dendritic cells

Enteropathogenic bacteria elicit mucosal innate and adaptive immune responses. We investigated whether gut epithelial cells played a role in triggering an adaptive immune response by recruiting dendritic cells (DCs). Immature DCs are selectively attracted by the CCL20 chemokine. The expression of the CCL20 gene in human intestinal epithelial cell lines was up-regulated by pathogenic bacteria, including Salmonella species, but not by indigenous bacteria of the intestinal flora. The Salmonella machinery for epithelial cell invasion was not required for CCL20 gene activation. Flagellin but not the lipopolysaccharide was found to be the Salmonella factor responsible for stimulation of epithelial CCL20 production. CCL20 in turn triggered a specific migration of immature DCs. Our data show that crosstalk between bacterial flagellin and epithelial cells is essential for the recruitment of DCs, a mechanism that could be instrumental to initiate adaptive immune responses in the gut.

Selective attraction of naive and memory B cells by dendritic cells

In this study, we investigate whether dendritic cells (DC), known to interact directly with T and B cells, might also contribute to the recruitment of B cells through the production of chemotactic factors. We found that B cells responded to several chemokines (CXCL12, CCL19, CCL20, and CCL21), which can be produced by DC upon activation. In addition, supernatant from DC (SNDC) potently and selectively attracted naive and memory B cells but not germinal center (GC) B cells or other lymphocytes (CD4(+), CD8(+) T cells or NK cells). Production of this activity was restricted to DC and was not increased following DC activation by LPS or CD40 ligand. Surprisingly, the B-cell chemotactic response to SNDC was insensitive to pertussis toxin treatment. In addition, the chemotactic factor(s) appeared resistant to protease digestion and highly sensitive to heat. This suggested that the DC chemotactic factor(s) is different from classical chemoattractants and does not involve G(alpha(i)) proteins on the responding B lymphocytes. It is interesting that SNDC was able to synergize with several chemokines to induce massive migration of B lymphocytes. These observations show that DC spontaneously produce factors that, alone or in cooperation with chemokines, specifically regulate B-cell migration, suggesting a key role of DC in the recruitment or localization of B lymphocytes within secondary lymphoid organs.

Dendritic cells and viral immunity: friends or foes?

Dendritic cells (DC) residing in epithelial tissues of various mucosae and the skin are characterized by the unique ability to capture antigens and migrate to draining lymph nodes, where they can activate naive and memory T cells. Although DC play a pivotal role in inducing protective immunity to viral infection, they can also be exploited by viruses to evade the host immune response, induce immune suppression, or serve as latent viral reservoirs. Thus, virus interactions with DC may lead to an immune response that can be protective, but does not necessarily lead to complete virus elimination, resulting in immunopathology.

Temporal order and spatial memory in schizophrenia: a parametric study

Spatial working memory has been shown to be impaired in schizophrenia. In contrast, memory for temporal order has been poorly studied in patients with schizophrenia. The aim of this study was to compare and to further characterize spatial working memory and sequence reproduction deficits in patients with schizophrenia under stable medication by manipulating cues (pattern versus sequence), delay, set-size and response type in various recall and recognition tasks. This allowed us to dissociate processes as encoding, retention and retrieval and to compare the performance of patients with schizophrenia to the performance of patients with prefrontal lesions, who have been previously tested in the same tasks. Our results show that increase of the set-size and of the delay decreased performance of both groups, and that these factors had larger detrimental effects in patients with schizophrenia than in controls. Furthermore, comparison between tasks revealed retention and retrieval deficits in schizophrenia. Finally, patients with schizophrenia showed impairments not only in recall but also in sequence recognition tasks with delay. This is in contrast to patients with prefrontal lesions, who have previously been shown to have intact recognition of sequences after a delay. These results suggest that the working memory deficit in schizophrenia cannot be restricted to a prefrontal dysfunction.

Dendritic cells recruitment and in vivo priming of CD8+ CTL induced by a single topical or transepithelial immunization via the buccal mucosa with measles virus nucleoprotein

The buccal mucosa, a prototype of pluristratified mucosal epithelia, contains a network of directly accessible class II(+) epithelial dendritic cells (DC), similar to skin Langerhans cells. We showed that a single buccal immunization with measles virus nucleoprotein (NP), by either topical application onto or intradermal injection in the buccal mucosa, induced in vivo priming of protective class I-restricted specific CD8(+) CTL. Both routes of immunization with NP induced a rapid recruitment of DC into the mucosa, which peaked at 2 h and decreased by 24 h. Treatment of mice with Flt3 ligand resulted in an increased number of DC in the buccal mucosa and enhanced the frequency of IFN-gamma-producing NP-specific effectors and the NP-specific CTL response generated after buccal immunization with NP. Finally, NP-pulsed bone marrow-derived DC induced NP-specific IFN-gamma-producing cells upon adoptive transfer to naive mice. These data demonstrate that a viral protein delivered to DC of the buccal mucosa induces in vivo priming of protective anti-viral CD8(+) CTL.

Relationship between discrimination tasks of the cantab and the corpus callosum morphology in Alzheimer's disease

The relationship between performances on a simple discrimination task of the Attentional Set Shifting of the Cambridge Neuropsychological Test Auto mated Battery (CANTAB) and morphometry of the corpus callosum is examined in patients with Alzheimer's disease. Analysis showed patients with probable Alzheimer's disease are heterogeneous for the relationship between performances in the attentional test of the CANTAB and the anterior callosal atrophies. Interest in these results for clinical diagnosis of this mental disease is discussed.

Gelatinase B functions as regulator and effector in leukocyte biology

Matrix metalloproteinases (MMPs) form a family of enzymes with major actions in the remodeling of extracellular matrix (ECM) components. Gelatinase B (MMP-9) is the most complex family member in terms of domain structure and regulation of its activity. Gelatinase B activity is under strict control at various levels: transcription of the gene by cytokines and cellular interactions; activation of the pro-enzyme by a cascade of enzymes comprising serine proteases and other MMPs; and regulation by specific tissue inhibitors of MMPs (TIMPs) or by unspecific inhibitors, such as alpha2-macroglobulin. Thus, remodeling ECM is the result of the local protease load, i.e., the net balance between enzymes and inhibitors. Glycosylation has a limited effect on the net activity of gelatinase B, and in contrast to the all-or-none effect of enzyme activation or inhibition, it results in a higher-level, fine-tuning effect on the ECM catalysis by proteases in mammalian species. Fast degranulation of considerable amounts of intracellularly stored gelatinase B from neutrophils, induced by various types of chemotactic factors, is another level of control of activity. Neutrophils are first-line defense leukocytes and do not produce gelatinase A or TIMP. Thus, neutrophils contrast sharply with mononuclear leukocytes, which produce gelatinase A constitutively, synthesize gelatinase B de novo after adequate triggering, and overproduce TIMP-1. Gelatinase B is also endowed with functions other than cleaving the ECM. It has been shown to generate autoimmune neo-epitopes and to activate pro-IL-1beta into active IL-1beta. Gelatinase B ablation in the mouse leads to altered bone remodeling and subfertility, results in resistance to several induced inflammatory or autoimmune pathologies, and indicates that the enzyme plays a crucial role in development and angiogenesis. The major human neutrophil chemoattractant, IL-8, stimulates fast degranulation of gelatinase B from neutrophils. Gelatinase B is also found to function as a regulator of neutrophil biology and to truncate IL-8 at the amino terminus into a tenfold more potent chemokine, resulting in an important positive feedback loop for neutrophil activation and chemotaxis. The CXC chemokines GRO-alpha, CTAP-III, and PF-4 are degraded by gelatinase B, whereas the CC chemokines MCP-2 and RANTES are not cleaved.

Use of haplotype information to test involvement of the LRP gene in Alzheimer's disease in the French population

The low density lipoprotein receptor-related protein gene (LRP) is a good candidate gene for Alzheimer's Disease (AD). Its protein is involved in the physiopathology of AD and has been found in senile plaques; on the other hand, LRP is located in 12q, a region in which genetic linkage to AD was reported. Two common polymorphisms, a tetranucleotide repeat in the 5' untranslated region and a single nucleotide polymorphism at position 766 in exon 3, were found to be associated with AD, but contradictory results were obtained in subsequent association studies. In the absence of clear hypotheses concerning the association of these polymorphisms with AD and their functional role, our objective was to test the association between AD and the two LRP polymorphisms in a large French case-control sample (274 Caucasian AD patients and 290 matched controls) using haplotype analysis. First, the separate study of each polymorphism showed no significant difference in genotype and allele frequencies between AD cases and controls. Second, strong linkage disequilibrium was found between alleles of the two polymorphisms in controls and in cases and the linkage disequilibrium between the 91 bp and C alleles were opposite in cases and in controls. Third, we found that the frequency of the 91-C haplotype was higher in cases than in controls, but the type I error was 0.061, slightly higher than the conventional one of 5%. The haplotype frequencies did not vary significantly as a function of age and APOE epsilon4 status. One interest in this study is the use of the haplotype analysis, which can be used to combine information from several polymorphisms, taking into account their dependence.

Preserved Adjustment but Impaired Awareness in a Sensory-Motor Conflict following Prefrontal Lesions

Control of action occurs at different stagesof the executive process, in particular at those of sensory-motor integration and conscious monitoring. The aim of this study was to determine the implication of the prefrontal cortex in the control of action. For that purpose, we compared the performance of 15 patients with frontal lobe lesions and 15 matched controls on an experimental paradigm generating a conflict between the action planned and the sensory-motor feedback. Subjects had to trace a sagittal line witha stylus on a graphic tablet. The hand was hidden by a mirror on which the traced line, processed by a computer, was projected. Without informing the subjects, the line traced was modified by introducing a bias to the right, which increased progressively from 2° to 42°. To succeed the task, subjects had to modify their motor program and deviate their hand in the opposite direction. The sensory-motor adjustment to the bias was evaluated by the surface between the line traced and the ideal line to compensate for the deviation. The awareness of the conflict was measured by the angle of the bias at which subjects expressed the feeling that the line they traced was not the same as the line they saw. The deviation was similarly compensated for by patients and controls until24°. Then 14 controls but only3 patients were aware of a conflict. After that, the variability of performance increased significantly for the unaware patients. These results suggest that the prefrontal cortex is required at the level of conscious monitoring of actions, but not at the level of sensory-motor integration.

The effects of apomorphine on attentional processing in Parkinson's disease

To ascertain whether variations in central dopaminergic transmission can differentially affect motor and cognitive processing, we studied the effects of apomorphine (APO) in 9 patients with Parkinson's disease (PD). The UPDRS motor scores and auditory event-related potentials (ERPs) obtained in the 'odd-ball' (OB) and in the 'covert orientation of attention' (COA) tasks were studied in the 'off' and in the 'on' state after an injection of APO. Although APO injection improved patients' motor status, it induced a significant increase in the latencies of the P2 and P3 ERP components in the OB. In the COA task, right-hand reaction times (RTs) were markedly shortened in the 'on' state while left hand RTs remained unchanged. The contrasting effects of dopaminergic stimulation on the motor performance and on some aspects of cognitive processing suggest the existence of complex interactions within pre- and postsynaptic brain dopamine receptors, and an intervention of segregated basal ganglia-prefrontal cortex loops in motor and cognitive behaviour.

The role of dorsolateral prefrontal cortex in the preparation of forthcoming actions: an fMRI study

The dorsolateral prefrontal cortex (DLPFC) plays a key role in working memory (WM). Yet its precise contribution (the storage, manipulation and/or utilization of information for the forthcoming response) remains to be determined. To test the hypothesis that the DLPFC is more involved in the preparation of actions than in the maintenance of information in short-term memory (STM), we undertook a functional magnetic resonance imaging investigation in normal subjects performing two delayed response tasks (matching and reproduction tasks) in a visuospatial task sequence (presentation, delay, response). In the two tasks, the presentation and delay phases were similar, but the expected response was different: in the matching task, subjects had to indicate whether a visuospatial sequence matched the sequence presented before the delay period; in the reproduction task, subjects had to reproduce the sequence and, therefore, to mentally organize their response during the delay. Using a fMRI paradigm focusing on the delay period, we observed a significant DLPFC activation when subjects were required to mentally prepare a sequential action based on the information stored in STM. When subjects had only to maintain a visuospatial stimulus in STM, no DLPFC activation was found. These results suggest that a parietal-premotor network is sufficient to store visuospatial information in STM whereas the DLPFC is involved when it is necessary to mentally prepare a forthcoming sequential action based on the information stored in STM.

Outcome of patients with HIV-1-related cognitive impairment on highly active antiretroviral therapy

OBJECTIVE

To examine the impact of highly active antiretroviral therapy (HAART) on the outcome of HIV-1-related cognitive impairments using a neuropsychological (NP) battery to assess separately the psychomotor, executive function and memory fields.

DESIGN

A longitudinal study of HIV-1-infected patients based on serial NP tests in a Paris University Hospital.

METHODS

A group of 91 HIV-1-infected patients, of whom 47 were already taking HAART at their first NP examination, were initially categorized as cognitively impaired (n = 53) or non-impaired (n = 38) and underwent one to six serial NP batteries (mean follow-up 12.3+/-8.3 months). Generalized estimating equations (GEE) were used to evaluate performance in a given NP test according to the number of days on HAART.

RESULTS

Despite a 25% mortality rate among patients who had cognitive impairment at their first NP examination, GEE showed a positive relationship between the duration of HAART and cognitive performance. Performance in psychomotor tests (e.g. Purdue Pegboard dominant hand) improved continuously during the study period, while memory test performance (e.g. Grober and Buschke free recall) tended to reach a plateau.

CONCLUSIONS

HAART improves subcortical cognitive functions during the first year of treatment. Distinct neuropathological mechanisms appear to underlie psychomotor and memory dysfunctions in AIDS.