Defect Of Memory Research Articles

Enhanced neuronal activity by suffruticosol A extracted from Paeonia lactiflora via partly BDNF signaling in scopolamine-induced memory-impaired mice

Neurodegenerative diseases are explained by progressive defects of cognitive function and memory. These defects of cognition and memory dysfunction can be induced by the loss of brain-derived neurotrophic factors (BDNF) signaling. Paeonia lactiflora is a traditionally used medicinal herb in Asian countries and some beneficial effects have been reported, including anti-oxidative, anti-inflammatory, anti-cancer activity, and potential neuroprotective effects recently. In this study, we found that suffruticosol A is a major compound in seeds of Paeonia lactiflora. When treated in a SH-SY5 cell line for measuring cell viability and cell survival, suffruticosol A increased cell viability (at 20 µM) and recovered scopolamine-induced neurodegenerative characteristics in the cells. To further confirm its neural amelioration effects in the animals, suffruticosol A (4 or 15 ng, twice a week) was administered into the third ventricle beside the brain of C57BL/6 mice for one month then the scopolamine was intraperitoneally injected into these mice to induce impairments of cognition and memory before conducting behavioral experiments. Central administration of suffruticosol A into the brain restored the memory and cognition behaviors in mice that received the scopolamine. Consistently, the central treatments of suffruticosol A showed rescued cholinergic deficits and BDNF signaling in the hippocampus of mice. Finally, we measured the long-term potentiation (LTP) in the hippocampal CA3–CA1 synapse to figure out the restoration of the synaptic mechanism of learning and memory. Bath application of suffruticosol A (40 µM) improved LTP impairment induced by scopolamine in hippocampal slices. In conclusion, the central administration of suffruticosol A ameliorated neuronal effects partly through elevated BDNF signaling.

A lightweight dead fish detection method based on deformable convolution and YOLOV4

The proposal of deep neural network achieves intelligent detection of abnormal fish behaviors. However, with the increase of network depth, the defects of large training memory and poor real-time performance restrict the deployment of the algorithm in aquaculture end devices. Therefore, this paper proposes a high-precision and lightweight end-to-end target detection model based on deformable convolution and improved YOLOv4. First of all, replacing the YOLOv4 backbone network with the lightweight network MobileNetV3 and replacing the standard convolution with a deep separable convolution have achieved a significant reduction in network parameters and calculations; Secondly, deformable convolution is used to improve the target feature extraction ability and increase the detection accuracy of the model in underwater images; Finally, an ablation experiment is conducted to compare the detection effect under different deformable convolution layers and network positions. Experimental results show that the combination of three-layer deformable convolution and standard convolution has the best performance. Compared with the YOLO series, the proposed model has an accuracy of 95.47% while the parameter amount is reduced by 10 times and the FPS is doubled. Rapid detection of dead fish is achieved in real circulating aquaculture systems.

Assessment of changes in immune status linked to COVID-19 convalescent and its clinical severity in patients and uninfected exposed relatives

IntroductionThe immune response during and after SARS-CoV-2 infection can be complex and heterogeneous, and it can be affected by the severity of the disease. It can also contribute to an unfavorable evolution and bring about short and long term effects. The aim of this study was to characterize the lymphocyte composition according to the severity of COVID-19, as well as its degree of relationship to the specific humoral response to SARS-CoV-2 in convalescents up to 106 days after the infection and in their exposed relatives. MethodsAn applied research was carried out with a cross-section analytical design, from March 11 to June 11, 2020 in Cuba. The sample consisted of 251 convalescents from COVID-19 over 18 years of age and 88 exposed controls who did not become ill. The B and T cell subpopulations, including memory T cells, as well as the relationship with the humoral immune response against SARS-CoV-2, were identified by flow cytometry and enzyme immunoassay. ResultsConvalescent patients, who evolved with severe forms, showed a decrease in frequency and a greater proportion of individuals with values ​​lower than the minimum normal range of B cells, CD3 + CD4 + cells and the CD4 + / CD8 + ratio, as well as a higher frequency and a greater proportion of individuals with values ​​above the normal maximum range of CD3 + CD8 + and NK cells. Convalescent patients with severe forms of COVID-19 that exhibited IgG / RBD titers ≥ 1/200 had a lower frequency of TEMRA CD8 + cells (p = 0.0128) and TEMRA CD4 + (p = 0.0068). IgG / RBD titers were positively correlated with the relative frequency of CD4 + CM T memory cells (r = 0.4352, p = 0.0018). ConclusionsThe identified alterations of B and T lymphocytes suggest that convalescent patients with the severe disease could be vulnerable to infectious, autoimmune or autotinflammatory processes; therefore, these individuals need medical follow-up after recovering from the acute disease. Furthermore, the role of T cells CD4 + CM in the production of antibodies against SARS-CoV-2 is confirmed, and it is noted that the defect of memory T cells CD8 + TEMRA could contribute to the development of severe forms of COVID-19.

3-Hydroxykynurenine as a Potential Ligand for Hsp70 Proteins and Its Effects on Drosophila Memory After Heat Shock

Kynurenine products of tryptophan metabolism are modifiers of the nervous activity and oxidative processes in mammals and invertebrates. 3-Hydroxykynurenine (3HOK) in moderate concentrations is a lipid peroxidation inhibitor. However, its accumulation and oxidative auto-dimerization lead to oxidative stress development manifested in age-related neurodegenerative diseases (NDD) and neurological disorders provoked by acute stress. Different forms of stress, the mostly studied being heat shock response, rely on functioning of heat shock proteins of the Hsp70 superfamily. Since kynurenines are called "kids of stress," we performed computational estimation of affinity of 3HOK and other kynurenines binding to predicted ATP site of Drosophila melanogaster Hsp cognate 71 protein (Dhsp71) using AutoDock Vina. The binding energy of 3HOK dimer is - 9.4kcal/mol; its orientation within the active site is close to that of ATP. This might be a new mechanism of producing a competitive inhibitor of Hsp70 chaperones that decreases organism ability to adapt to heat shock. We also showed that the Drosophila cardinal (cd1) mutant with 3HOK excess, serving as a model for Huntington's disease (HD), manifests severe defects of short-term memory after heat shock applied either in adults or at the prepupal stage.

β3-adrenoceptor activation exhibits a dual effect on behaviors and glutamate receptor function in the prefrontal cortex

β-adrenoceptor (β-AR), especially the β1- and β2-AR subtypes, is known to participate in stress-related behavioral changes. Recently, SR58611A, a brain-penetrant β3-AR agonist, exhibits anxiolytic- and antidepressant-like effects. In this study, we sought to study the role of SR58611A in behavioral changes and its potential cellular and molecular mechanism in the prefrontal cortex (PFC). We found that rats with SR58611A (1 mg/kg) enhanced PFC-mediated recognition memory, whereas administration of higher dosage of SR58611A (20 mg/kg) caused hyperlocomotion, and exhibited an impairment effect on recognition memory. Electrophysiological data also indicated that SR58611A (1 mg/kg) selectively enhanced NMDA receptor-mediated excitatory postsynaptic currents (EPSC) through interacting with norepinephrine (NE) system and activating β3-AR, whereas higher dosage of SR58611A (20 mg/kg) reduced both AMPA receptor- and NMDA receptor-mediated EPSC. SR58611A-induced different effects on EPSC linked with the change of the surface expression quantity of NMDA receptor and/or AMPA receptor subunits. Synaptosomal-associated protein 25 (SNAP-25), which is a key soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein involved in incorporation of NMDA receptor to postsynaptic membrane, contributed to SR58611A (1 mg/kg)-induced enhancement of recognition memory and NMDA receptor function. Moreover, SR58611A (1 mg/kg) could rescue repeated stress-induced defect of both recognition memory and NMDA receptor function through a SNAP-25-dependent mechanism. These results provide a potential mechanism underlying the cognitive-enhancing effects of SR58611A (1 mg/kg).

Prospective memory is dysfunctional in migraine without aura.

Introduction Prospective memory is the ability to carry out a delayed intended action, so to maintain and retrieve future plans, goals and activities. Deficits of prospective memory negatively impact on patients and caregivers' everyday living and determine poor adherence to treatment. Since frontal regions are involved in both event- and time-based prospective memory tasks and are impaired in migraine without aura, defects of prospective memory might occur in migraine without aura patients; until now this issue has not been investigated. The aim of the current study was to explore time- versus event-based prospective memory in migraine without aura. Patients and methods Ninty-one consecutive migraine without aura patients and 84 healthy subjects were enrolled in the study. They underwent a standardized measure of prospective memory evaluating both time-based and event-based prospective memory, and the Montreal Cognitive Assessment assessing global cognitive status. Moreover, all participants completed the Beck Depression Inventory-II and a self-administered version of the Apathy Evaluation Scale, to assess severity of depressive symptoms and apathy, respectively. Results Migraine without aura and healthy subjects did not differ on demographic aspects (i.e. age, education and gender). However, individuals with migraine without aura demonstrated impaired prospective memory performance compared to healthy subjects, with a greater impairment demonstrated for the time-based tasks. Within the migraine without aura group, no significant association was found between prospective memory performance and clinical scores, apathy, and depression. Conclusions Individuals with migraine without aura experience particular difficulty executing a future intention; therefore, migraine without aura is associated with dysfunction of prospective memory.

Predicting progression of amnesic MCI: The integration of episodic memory impairment with perfusion SPECT

The present study aimed at assessing if the ability to predict progression from amnesic Mild Cognitive Impairment (aMCI) to dementia is improved by considering the presence at the baseline of Single Photon Emission Computed Tomography (SPECT) perfusion abnormalities in addition to a defect of long term memory.The Episodic Memory Score (EMS), a global index which integrates results obtained in subtests of the Rey's Verbal Learning Test and the Rey-Osterrieth Figure recall, were taken into account to evaluate defects of long term memory. The study sample consisted of 42 subjects affected by aMCI, who were followed-up during a two-year period. At the final follow-up 15 subjects progressed to AD. The EMS predicted progression from aMCI to dementia with a high level of sensitivity and a lower level of specificity, but the association of neuropsychological (EMS) and SPECT data (hypoperfusion in the Posterior Cingulate Cortex) increased the accuracy in predicting conversion from aMCI to AD. The association of results obtained by aMCI patients on memory tests and perfusion SPECT may improve the accuracy in detecting subjects who will progress to dementia. The use of currently available and low-cost investigations could be advantageous in terms of public health policies.

A behavioral defect of temporal association memory in mice that partly lack dopamine reuptake transporter.

Temporal association memory, like working memory, is a type of episodic memory in which temporally discontinuous elements are associated. However, the mechanisms that govern this association remain incompletely understood. Here, we identify a crucial role of dopaminergic action in temporal association memory. We used hemizygote hyperdopaminergic mutant mice with reduced dopamine transporter (DAT) expression, referred to as DAT+/− mice. We found that mice with this modest dopamine imbalance exhibited significantly impaired trace fear conditioning, which necessitates the association of temporally discontinuous elements, and intact delay auditory fear conditioning, which does not. Moreover, the DAT+/− mice displayed substantial impairments in non-matching-to-place spatial working-memory tasks. Interestingly, these temporal association and working memory deficits could be mimicked by a low dose of the dopamine D2 receptor antagonist haloperidol. The shared phenotypes resulting from either the genetic reduction of DAT or the pharmacological inhibition of the D2 receptor collectively indicate that temporal association memory necessitates precise regulation of dopaminergic signaling. The particular defect in temporal association memory due to partial lack of DAT provides mechanistic insights on the understanding of cognitive impairments in multiple neurodevelopmental disorders.

Early Central Nervous System Complications after Allogeneic Stem Transplantation: A Single-Center Analysis of 723 Patients Including 456 Cord Blood Recipients

▪<Introduction>Early central nervous system (CNS) complications have been associated with significant morbidity and mortality after allogeneic stem cell transplantation (Allo-SCT). However, the incidence, etiology and clinical characteristics of early CNS complications have not been well understood. Moreover, the impact of stem cell sources on early CNS complications remains to be determined.<Methods>To address these issues, we retrospectively reviewed the medical record of 723 consecutive patients who underwent first Allo-SCT at Toranomon Hospital between 2006 and 2013. Early CNS complications were defined as distinct CNS manifestations such as convulsion, change of mental state, defect of short-term memory, or focal motor or sensory symptoms, occurring within 100 days post-transplant. The etiology of CNS complications was determined by clinical, radiologic, or microbiological finding or a combination of these factors. Patients who developed transient consciousness disturbances in septic state or circulatory collapse, had a history of brain surgery, or showed change of mental status at the terminal stage of multiple organ failures, were excluded from CNS complications. CNS relapses of underlying diseases were also excluded from this analysis.<Results>Their median age was 56 years (range, 16-82). Underlying diseases were AML in 360, MDS/MPD in 76, CML in 21, ALL in 82, ATL in 30, HL in 11, NHL in 109, AA in 23 and others in 11. Four hundred ninety-nine (69%) were not in remission at the time of transplant. Three hundred ninety-five patients (54.6%) were conditioned with myeloablative regimens, whereas 328 patients received reduced-intensity regimens. Donor sources consisted of related peripheral blood /bone marrow (BM) (n=101), unrelated BM (166) or cord blood (456). One hundred thirty-seven developed CNS complications on median of 25 (3-89) days post-transplant. Cumulative incidence of CNS complications at 100 days was 19%. The etiology included human herpesvirus 6 (HHV-6) encephalitis/myelitis (n=52), Non HHV-6 viral infections (4), bacterial infections (10), cerebrovascular diseases (18), thrombotic microangiopathy (TMA) / posterior reversible encephalopathy syndrome (PRES) (10), others (3) and unknown causes (40). With median observation period of survivors of 791 (27-2919) days, overall survival at 2 years was 26% in patients who developed CNS complication and was significantly worse than in those who did not develop it (46%, p<0.01) (Figure). In univariate analysis, disease status (high risk or standard risk), recipient age (age<55 or ≥55), underlying disease (lymphoid or others) had no impact on the incidence of early CNS complications. Patients who received cord blood transplantation (CBT) showed significantly higher incidence of CNS complications compared to those receiving other donor sources (25.5% vs 7.9%, p<0.01). In multivariate analysis, CBT was the only significant risk factor for CNS complications (HR=3.59, 95% CI 2.26-5.70, p<0.01). Incidence of HHV-6 encephalitis/myelitis was significantly higher in CBT recipients than other donor sources (11.0% vs 0.7%, p<0.01) (Table). Interestingly, the incidences of infectious complications other than HHV-6 were comparable between donor sources, suggesting there is a preferential vulnerability to HHV-6 infections in CB recipients. We have recently reported close association between the development of pre-engraftment immune reactions (allo-immune reactions unique to CBT) and of HHV-6 encephalitis (ASH 2012). Not just slow immune reconstitution following CBT, but other immune-mediated mechanisms may have contributed to the development of HHV-6 encephalitis.<Conclusion>Early CNS complications are serious concerns leading to inferior survival rate after Allo-SCT. Cord blood recipients are at higher risk for developing CNS complications, particularly of HHV-6 associated. Mechanisms behind them and optimal treatment approaches need to be clarified further to improve outcome. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Simulation Study of Magnetic Memory Signal Correlation Effect of Dual Defects by ANSYS

To study the correlation effect of multiple defects of metal magnetic memory (MMM) testing technology, the stress-magnetization effect on 20# steel specimen with dual defects under exercise of the geomagnetic field and tensile load is simulated by using the finite element analysis (FEA) software ANSYS. With the stimulation, the magnetic flux leakage (MFL) distribution with different measured paths and different lift-off values of the surface specimen is given. The results showed that the correlation effect of dual defects produce more severe stress concentration phenomenon on the associated region of ferromagnetic specimen, and had no obvious effect on the edge of ferromagnetic materials; Gradient value K of the normal component H(z) of leakage magnetic field in the specimen, as a parameter evaluation of stress concentration in the specimen, has high reliability in areas without correlation effect, but it has no credibility in areas under dual defect correlation effect. Moreover, this article also discusses the influence of measured path and the lift-off value on magnetic memory signals.

Probable Alzheimer's Disease Patients Presenting as “Focal Temporal Lobe Dysfunction” Show a Slow Rate of Cognitive Decline

Several authors have recently shown that anterograde amnesia is often associated with semantic memory impairment in amnesic MCI patients. Similarly, after the MCI condition, some patients who convert to Alzheimer's disease (AD) show the classic onset (cAD) characterized by the impairment of memory and executive functions, whereas other AD patients show isolated defects of episodic and semantic memory without deficits in other cognitive domains. The latter have been considered an AD variant characterized by 'focal Temporal Lobe Dysfunction' (TLD). The aim of the present study was to assess the differences in disease progression between cAD and TLD. For this purpose a continuous series of newly diagnosed probable AD patients presenting as cAD (n = 30) and TLD (n = 25), matched for severity, and 65 healthy controls underwent a comprehensive neuropsychological evaluation at baseline; TLD and cAD were re-evaluated at a 24-month follow-up. At follow-up, TLD patients showed no significant worsening of cognitive functions, whereas cAD subjects displayed a significant worsening in all explored cognitive domains. In conclusion, our results confirm that probable AD presenting as TLD represents a specific onset of AD characterized by a slower rate of progression.

Memory T cells generated in youth function well in old age (49.8)

Abstract Aging-associated changes negatively influence T cell responses. Since we previously observed that the memory CD8 T cells generated in aged mice have substantially reduced proliferative expansion upon secondary infection, we wanted to investigate if observed defects of memory T cells are due to the age of the cell or the age of the host when primed. Briefly, virus-specific memory T cells were generated by infecting young mice, aged mice or by infecting mice when they were young, but then allowing these mice to age for 2 years. T cells from these three groups were adoptively transferred to congenic young mice and these recipient mice were challenged to assess the recall capacity of memory T cells. We used both systemic (vaccinia virus or LCMV) and local (influenza virus) challenge models to investigate whether there were differences in the ability to respond to different types of infections and to assess the recall capacity of virus-specific T cells. Strikingly, the memory CD8 and CD4 T cells that were primed in young mice and then aged for 2 years responded as well as the memory T cells primed recently in young mice. These highly functional memory T cells appear largely impervious to age-associated changes occurring in their environment. As expected, memory CD8 and CD4 T cells recently generated in aged mice fail to mount strong recall responses. To conclude, our studies point to events during priming and the starting of T cell population in aged mice as a key area of focus.

記憶障碍 (健忘症) の人への援助技術 人生回想面接による記憶再生・共感関係・自己統合

記憶障碍 (健忘症) の人への援助技術 人生回想面接による記憶再生・共感関係・自己統合

Patterns of Cognitive Decline and Rates of Conversion to Dementia in Patients with Degenerative and Vascular forms of MCI

According to recent criteria, Mild Cognitive Impairment (MCI) represents a clinical condition with multiple cognitive presentations (amnesic and non amnesic) that can be supported by different types of brain lesions (mainly vascular and atrophic). In order to asses if the cognitive presentation and the rate of progression differ according to the type of brain pathology, two populations of MCI patients, characterized by hippocampal atrophy (n: 39) and vascular subcortical pathology (n: 36) respectively, on the basis of MRI findings, were investigated. Patients underwent an extensive neuropsychological test battery twice (at baseline and at two years follow-up), which is made up of the MMSE and various tests of episodic memory, short-term memory, visual-spatial abilities, executive functions, language, attention, praxis and psychomotor speed. Atrophic and vascular MCI patients showed a remarkably different pattern of impairment at the baseline. The former were significantly more impaired in episodic memory tasks. The latter were more impaired in an action naming task. At the follow up examination, the rate of progression to dementia was higher in atrophic (14/39) than in vascular (5/36) MCI patients. The comparison between neuropsychological scores obtained at the baseline and at the follow-up showed that atrophic MCI patients underwent a severe decline in several cognitive domains, whereas vascular MCI patients showed a significant decline only in those tasks requiring executive abilities. Our results confirm that a selective and severe defect of episodic memory is associated with hippocampal atrophy and that MCI patients with atrophic lesions are more likely to convert to Alzheimer's type dementia while MCI patients with vascular lesions are characterized by a slight decline in executive function over time and by a tendency to develop probable vascular forms of dementia.

Postictal hyperfamiliarity for unknown faces

Hyperfamiliarity for unknown faces (HFUF) is a rare disorder in which unfamiliar people or faces appear familiar. Three young adults were admitted for acute symptomatic secondarily generalized tonic–clonic seizures (two) and psychomotor status (one). During the days following the seizures the patients continuously experienced a strong familiarity for unknown people, including other patients, visitors, and hospital staff. This disorder disappeared gradually, lasting a mean of 13 days. Brain MRI showed left amygdalohippocampal lesions, suggesting the etiology of encephalitis in two patients and multiple “active” demyelinating lesions in one patient. Interictal and ictal EEG findings showed left temporal epileptiform abnormalities. Two patients had a transitory defect of verbal memory. HFUF is a newly defined postictal symptom, more likely to arise from left temporal epileptic discharges. In our cases it was associated with acute lesions of the temporal areas, suggesting that its occurrence may also imply a structural etiology of epilepsy.

Long-term immune deficiency after allogeneic stem cell transplantation: B-cell deficiency is associated with late infections

Immune reconstitution was analyzed in 140 consecutive patients who were 2-year disease-free and who underwent myeloablative allogeneic transplantation. A CD4 and CD8 defect was observed involving naive, terminally differentiated, memory and competent cells and above limits values for activated subsets. Natural killer cells normalize at six months while we observed expansion of CD19(+)/CD5(+) B cells after three months and a persisting defect of memory B cells. Chronic graft-versus-host disease did not influence significantly those parameters for CD8 subsets while the naïve and competent CD4 subsets were strongly affected. But the most profound impact of chronic graft-versus-host disease was on B-cell subsets, especially on the memory B population. The cumulative incidence of late severe infections was low (14% at four years). Using Cox's models, only low B-cell counts at 12 (P=0.02) and 24 (P=0.001) months were associated with the hazard of developing late infection, in particular if patients did not develop chronic graft-versus-host disease.

Prenatal exposure to heroin in mice elicits memory deficits that can be attributed to neuronal apoptosis

Maternal heroin abuse has been shown to result in teratogenic neurobehavioral defects in the offspring, but the underlying mechanisms remain largely unknown. This study was designed to explore the role of neuronal apoptosis in the heroin-induced neurobehavioral defects of learning and memory. Pregnant BALB/c mice were treated with either heroin or saline. The animals in the heroin group received heroin subcutaneously at a dosage of 10 mg/kg/day on embryonic days (E) 9–18, while those in the saline group were treated as drug-naive. Offspring were grouped as prenatal heroin exposure (HER), prenatal saline exposure (SAL), and control (CON) groups, according to the maternal treatment regimen. Some of the mice were killed and their hippocampus harvested on postnatal day (P) 14, and the tissue subjected to reverse transcription polymerase chain reaction, Western blotting, and immunohistochemistry to reveal the mRNA and protein expressions of caspase-3, Bcl-2, and Bax. The Morris water maze was applied to assess the learning and memory capability of the mice at P30; poor maze performances were observed for the animals in the HER group. The results also showed that the mRNA and protein expressions of caspase-3 and Bax were significantly increased, while that of Bcl-2 was markedly decreased in the HER group compared with both the SAL and CON groups. The immunohistochemistry revealed significant caspase-3 immunoreactivity in the dentate gyrus and cornu ammonis (CA) 1 subareas of the hippocampal formation, whereas, no significant changes were seen in subarea CA3. These findings suggest that prenatal heroin exposure during the E9–18 period enhances neuronal apoptosis by altering the expressions of caspase-3, Bcl-2, and Bax in the mouse hippocampus, and leads to impairment in hippocampus-dependent learning and memory.

Infections in 252 Patients with Common Variable Immunodeficiency

Common variable immunodeficiency is characterized by recurrent infections and defective immunoglobulin production. The DEFI French national study prospectively enrolled adult patients with primary hypogammaglobulinemia. Clinical events before inclusion were retrospectively analyzed at that time. From April 2004 through April 2007, 341 patients were enrolled, 252 of whom had received a diagnosis of common variable immunodeficiency; of those, 110 were male, 142 were female, and 228 were white. The median age at first symptoms was 19 years. The median age at common variable immunodeficiency diagnosis was 33.9 years. The median delay for diagnosis was 15.6 years for the 138 patients with initial symptoms before 1990 and 2.9 years for the 114 patients with initial symptoms from 1990 to the time of the study. The most frequent initial symptoms were upper respiratory tract infections: bronchitis (in 38% of patients), sinusitis (36%), pneumonia (31%), and/or bronchiectasis (14%). Overall, 240 patients had respiratory symptoms. Pneumonia was reported in 147 patients; Streptococcus pneumoniae and Haemophilus influenzae were documented in 46 and 17 cases, respectively. Recurrent or chronic diarrhea was reported in 118 patients. Giardia (35 cases), Salmonella (19), and Campylobacter (19) infections were more frequent in patients with undetectable serum immunoglobulin A (P<.001). Sixteen patients developed opportunistic infections. Persistent infections and requirement for antibiotics despite immunoglobulin substitution correlated with severe defect of memory switched B cells (P=.003) but not with immunoglobulin G trough levels (P=.55). Although reduced within the past decade, the delay of diagnosis of common variable immunodeficiency remains unacceptable. Recurrence of upper respiratory tract infection or pneumonia should lead to systematic evaluation of serum immunoglobulin.

Functional Mechanisms of Episodic Memory Impairment in Schizophrenia

To achieve a better understanding of the functional mechanisms underlying episodic memory dysfunction in schizophrenia, which is a prerequisite for unravelling schizophrenia's neural correlates in neuroimaging studies and, more generally, for developing an integrated approach to the pathophysiology of schizophrenia. It is also crucial for developing cognitive remediation. This paper reviews empirical evidence of episodic memory dysfunction in schizophrenia obtained with reference to various theoretical models of episodic memory. All the studies converge to show a significant impairment of the critical feature of episodic memory: conscious recollection. Schizophrenia is also associated with a defect of autobiographical memory. The episodic memory dysfunction results from a predominant failure of strategic processing at encoding, although an impairment of strategic processing at retrieval cannot be ruled out. The possibility that it is not the execution of the encoding strategies that is defective but, rather, their self-initiation by the patients is plausible. These findings may explain some behavioural abnormalities associated with schizophrenia, notably, inadequate functional outcomes in everyday life. They may also have implications for cognitive remediation and better social and work functioning of patients with schizophrenia.

Peripheral vestibular damage causes impaired navigation tasks on memorized routes in humans

Objectives To investigate if a well-compensated unilateral peripheral vestibular hypofunction could interfere with navigation tasks on memorized routes in humans. Methods After a complete otoneurological investigation, fifty labyrinthine-defective patients and fifty controls were invited to visually memorize three different routes (a triangle, a circle and a square) on a grey carpet and then to walk along them with eye closed clockwise and counter-clockwise (mental map navigation). The same test was then repeated with eye open (actual navigation) and again with eye closed (mental navigation). Execution time was recorded in each test. Corsi block test and a psychiatric questionnaire completed the neuropsychological examination. Results Labyrinthine-defective patients showed higher levels of anxiety and depression and performed Corsi block test with more difficulties than controls. Patients spent more time than controls in the first and third session (eye closed). No difference was recorded between clockwise and counter-clockwise navigation tasks both in patients and in controls. Patients showed a greater improvement in the third navigation task than controls. Conclusion Walking on memorized routes in non-visual condition is impaired by a peripheral vestibular damage, even if patients are well compensated. This impairment could be due to a defect of the visuospatial short-term memory, as supported by Corsi block tests, but a residual sensorimotor impairment and/or an interference of psychological distress could not be definitively excluded.