New Insights into the Mechanism of Antibacterial Action of Synthetic Peptide Mo-CBP3-PepI against Klebsiella pneumoniae.

Klebsiella pneumoniae is a multidrug-resistant opportunistic human pathogen related to various infections. As such, synthetic peptides have emerged as potential alternative molecules. Mo-CBP3-PepI has presented great activity against K. pneumoniae by presenting an MIC50 at a very low concentration (31.25 µg mL-1). Here, fluorescence microscopy and proteomic analysis revealed the alteration in cell membrane permeability, ROS overproduction, and protein profile of K. pneumoniae cells treated with Mo-CBP3-PepI. Mo-CBP3-PepI led to ROS overaccumulation and membrane pore formation in K. pneumoniae cells. Furthermore, the proteomic analysis highlighted changes in essential metabolic pathways. For example, after treatment of K. pneumoniae cells with Mo-CBP3-PepI, a reduction in the abundance of protein related to DNA and protein metabolism, cytoskeleton and cell wall organization, redox metabolism, regulation factors, ribosomal proteins, and resistance to antibiotics was seen. The reduction in proteins involved in vital processes for cell life, such as DNA repair, cell wall turnover, and protein turnover, results in the accumulation of ROS, driving the cell to death. Our findings indicated that Mo-CBP3-PepI might have mechanisms of action against K. pneumoniae cells, mitigating the development of resistance and thus being a potent molecule to be employed in producing new drugs against K. pneumoniae infections.

Synergistic Antibiofilm Activity between Synthetic Peptides and Ciprofloxacin against Staphylococcus aureus.

Staphylococcus aureus is a human pathogen known to be resistant to antibiotics since the mid-20th century and is constantly associated with hospital-acquired infections. S. aureus forms biofilms, which are complex surface-attached communities of bacteria held together by a self-produced polymer matrix consisting of proteins, extracellular DNA, and polysaccharides. Biofilms are resistance structures responsible for increasing bacterial resistance to drugs by 1000 times more than the planktonic lifestyle. Therefore, studies have been conducted to discover novel antibacterial molecules to prevent biofilm formation and/or degrade preformed biofilms. Synthetic antimicrobial peptides (SAMPs) have appeared as promising alternative agents to overcome increasing antibiotic resistance. Here, the antibiofilm activity of eight SAMPs, in combination with the antibiotic ciprofloxacin, was investigated in vitro. Biofilm formation by S. aureus was best inhibited (76%) by the combination of Mo-CBP3-PepIII (6.2 µg mL-1) and ciprofloxacin (0.39 µg mL-1). In contrast, the highest reduction (60%) of the preformed biofilm mass was achieved with RcAlb-PepII (1.56 µg mL-1) and ciprofloxacin (0.78 µg mL-1). Fluorescence microscopy analysis reinforced these results. These active peptides formed pores in the cellular membrane of S. aureus, which may be related to the enhanced ciprofloxacin's antibacterial activity. Our findings indicated that these peptides may act with ciprofloxacin and are powerful co-adjuvant agents for the treatment of S. aureus infections.

Antifungal Potential of Synthetic Peptides against Cryptococcus neoformans: Mechanism of Action Studies Reveal Synthetic Peptides Induce Membrane-Pore Formation, DNA Degradation, and Apoptosis.

Cryptococcus neoformans is a human-pathogenic yeast responsible for pneumonia and meningitis, mainly in patients immunocompromised. Infections caused by C. neoformans are a global health concern. Synthetic antimicrobial peptides (SAMPs) have emerged as alternative molecules to cope with fungal infections, including C. neoformans. Here, eight SAMPs were tested regarding their antifungal potential against C. neoformans and had their mechanisms of action elucidated by fluorescence and scanning electron microscopies. Five SAMPs showed an inhibitory effect (MIC50) on C. neoformans growth at low concentrations. Fluorescence microscope (FM) revealed that SAMPs induced 6-kDa pores in the C. neoformans membrane. Inhibitory assays in the presence of ergosterol revealed that some peptides lost their activity, suggesting interaction with it. Furthermore, FM analysis revealed that SAMPs induced caspase 3/7-mediated apoptosis and DNA degradation in C. neoformans cells. Scanning Electron Microscopy (SEM) analysis revealed that peptides induced many morphological alterations such as cell membrane, wall damage, and loss of internal content on C. neoformans cells. Our results strongly suggest synthetic peptides are potential alternative molecules to control C. neoformans growth and treat the cryptococcal infection.

What did we learn from neural grafts in Huntington disease?

Huntington's disease is a rare, severe, and inherited neurodegenerative disorder that affects young adults. To date, there is no treatment to stop its progression. The primary atrophy of the striatum in HD, is limited in space and centrally focalised in the brain and thus constitutes a good candidate for graft. Therefore, transplantation of foetal cells from the ganglionic eminence, the germinal zone of the striatum, has the potential to restore disrupted fronto-cortical circuits and corresponding clinical functions. The international Multicentric intracerebral Grafting in Huntington's disease trial was not as successful as two pilot trials (Créteil and London) which showed promising results in the 2000s, displaying stabilisation/recovery of symptoms in some patients. A point-by-point comparison of the differences between MIG-HD and the pilot trial from Créteil in which similar data are available provides lessons on the grafting procedure and allows for strategic thinking before embarking on future trials. MIG-HD demonstrated the existence of intracerebral alloimmunisation leading to acute or chronic graft rejection into the brain and showed the limitations of surgical standardisation and immunosuppression. It has also improved the safety of the procedure and provided guidance for the follow-up of future patients. Indeed, even if disease modifiers treatments are currently the focus of intense research, they may not stop or slow the progression of the disease sufficiently, or even be administered in all patients, to prevent brain atrophy in all cases. Although disease-modifying therapies are currently the subject of intense research, they may not stop or slow disease progression sufficiently, or may not be given to all patients to prevent brain atrophy. A combination with intracerebral transplantation to repair the damaged structures may thus prove beneficial. Altogether, pursuing research in intracerebral transplantation remains necessary.

Clinical description of the broad range of neurological presentations of COVID-19: A retrospective case series.

BACKGROUND: Neurological disorders associated with SARS-CoV-2 infection represent a clinical challenge because they encompass a broad neurological spectrum and may occur before the diagnosis of COVID-19. METHODS: In this monocentric retrospective case series, medical records from patients with acute neurological disorders associated with SARS-CoV-2 infection from medicine departments of an academic center in Paris area were collected between March 15th and May 15th 2020. Diagnosis of SARS-CoV-2 was ascertained through specific RT-PCR in nasopharyngeal swabs or based on circulating serum IgG antibodies. RESULTS: Twenty-six patients diagnosed with SARS-CoV-2 infection presented with neurological disorders: encephalitis (N=8), encephalopathy (N=6), cerebrovascular events (ischemic strokes N=4 and vein thromboses N=2), other central nervous system (CNS) disorders (N=4), and Guillain-Barré syndrome (N=2). The diagnosis of SARS-CoV-2 was delayed on average 1.6 days after the onset of neurological disorder, especially in case of encephalitis 3.9 days, encephalopathy 1.0 day, and cerebrovascular event 2.7 days. CONCLUSIONS: Our study confirms that COVID-19 can yield a broad spectrum of neurological disorders. Because neurological presentations of COVID-19 often occur a few days before the diagnosis of SARS-COV-2 infection, clinicians should take preventive measures such as patient isolation and masks for any new admission to avoid nosocomial infections. Anti-SARS-CoV2 antibody detection in RT-PCR SARS CoV-2 negative suspected cases is useful to confirm a posteriori the diagnosis of atypical COVID-19 presentations.

Striatal connectivity in pre-manifest Huntington's disease is differentially affected by disease burden.

BACKGROUND AND PURPOSE: Different amounts of cumulative exposure to the toxic mutant form of the huntingtin protein might underlie the distinctive pattern of striatal connectivity in pre-manifest Huntington's disease (pre-HD). The aim of this study was to investigate disease-burden-dependent cortical-striatal and subcortical-striatal loops at different pre-HD stages. METHODS: A total of 16 participants with pre-HD and 25 controls underwent magnetic resonance imaging to investigate striatal structural and functional connectivity (FC). Individuals with pre-HD were stratified into far-from-onset and close-to-onset disease groups according to the disease-burden score. Cortical-striatal and subcortical-striatal FC was investigated through seed-region of interest (ROI) and ROI-to-ROI approaches, respectively. The integrity of white-matter pathways originating from striatal seeds was investigated through probabilistic tractography. RESULTS: In far-from-onset pre-HD, the left caudate nucleus showed cortical increased FC in brain regions overlapping with the default mode network and increased coupling connectivity with the bilateral thalamus. By contrast, close-to-onset individuals showed increased fractional anisotropy (and mean diffusivity) in the right caudate nucleus and widespread striatal atrophy. Finally, we reported an association between cortical-caudate FC and caudate structural connectivity, although this did not survive multiple comparison correction. CONCLUSIONS: Functional reorganization of the caudate nucleus might underlie plasticity compensatory mechanisms that recede as individuals with pre-HD approach clinical symptom onset and neurodegeneration.

Guidelines for clinical pharmacological practices in Huntington's disease.

OBJECTIVE: Evidence-based medicine is a difficult goal to achieve in rare diseases where randomized controlled trials are lacking. This report provides guidelines that capitalize on both the literature and expertise of the French National Huntington Disease Reference Centre to optimalize pharmacological therapeutic interventions for Huntington's disease (HD). MATERIAL AND METHODS: HD experts conducted a systematic analysis of the literature from 1965 to 2013, using a scoring procedure established by the French National Authority for Health. These experts offered their views when evidence was missing to set up provisional guidelines for care in HD. These guidelines were then scored and amended through two subsequent online questionnaires (using SurveyMonkey® scoring), and one face-to-face meeting with an external multidisciplinary working group as a step towards validation. RESULTS: Except for the beneficial effects of tetrabenazine in chorea, none of the published recommendations were grounded on established scientific evidence. Second-generation antipsychotics are nevertheless the first choice for patients with psychiatric manifestations (low level of evidence). All other guidelines are based on low-level evidence and little professional agreement. CONCLUSION: Patients' care has greatly improved over the last few years despite the lack of high-level evidence standards. Guidelines are based on the expertise of trained specialists from the French National Plan for Rare Diseases. This strategy should now be extended internationally to promote future studies and to harmonize worldwide care of HD.

Regenerative medicine in Huntington's disease: current status on fetal grafts and prospects for the use of pluripotent stem cell.

Huntington's disease is currently incurable, but cell therapy is seen as a promising alternative treatment. We analyze the safety and efficacy of the intrastriatal transplantation of human fetal neuroblasts from ganglionic eminences in patients with Huntington's disease. A few rare surgical incidents were reported, but the main difficulty associated with this therapeutic approach is the occurrence of recipient alloimmunization against the graft and the lack of availability, standardization and quality control for the fetus-derived products required for cell therapy. Some patients showed sustained cognitive improvement over periods of more than six years, and motor improvements for more than four years. Grafting outcomes are variable even within individual transplantation centers. The reasons for this variability are poorly understood, highlighting the need for further research in this specific area. With the perspective of additional trials in the future, we review here the development of human pluripotent stem cell-derived cell therapy products for HD, and their advantages and disadvantages with respect to fetal cells.

Long-term neurocognitive effects of antipsychotics in schizophrenia: a network meta-analysis.

PURPOSE: Most schizophrenic patients have mild to moderate cognitive impairment in the early stages of schizophrenia. The aim was to compare the long-term effects of various antipsychotic drugs on overall cognition and on specific cognitive domains in patients with schizophrenia or related disorders. METHODS: We searched MEDLINE and EMBASE for randomized controlled trials in which oral formulations of second-generation antipsychotic drugs were compared head-to-head or against placebo or against haloperidol. Trials had to be of at least 6 months duration to be included. We used a network meta-analysis to combine direct and indirect comparisons of the cognitive effects between antipsychotics. RESULTS: Nine studies were eligible. The median trial duration was 52 weeks. Quetiapine, olanzapine and risperidone had better effects on global cognitive score than amisulpride (p < 0.05) and haloperidol (p < 0.05). When memory tasks were considered, ziprasidone had better effect than amisulpride (0.28 [0.02-0.54]) and haloperidol (0.32 [0.09-0.55]). Quetiapine was better than other drugs (p < 0.001) on attention and processing speed tasks, followed by ziprasidone (p < 0.05) and olanzapine (p < 0.05). The effects of quetiapine, risperidone and olanzapine were better than those of amisulpride (p < 0.05) on executive functions. CONCLUSIONS: Our results suggest differences between antipsychotics in their effect on the overall cognitive score in schizophrenia. Quetiapine and olanzapine had the most positive effects, followed by risperidone, ziprasidone, amisulpride and haloperidol in that order. Significant differences were also observed according to specific cognitive tasks.

High insulinlike growth factor I is associated with cognitive decline in Huntington disease.

OBJECTIVE: The somatotropic axis (growth hormone [GH] and insulinlike growth factor I [IGFI]) play a role in the cognitive deficits seen with aging, GH deficiency, and neurodegenerative disorders such as Alzheimer disease. We recently reported elevations in basal plasma GH and IGFI levels in patients with Huntington disease (HD). Here, our objective was to determine whether somatotropic axis abnormalities predicted cognitive dysfunction in HD. METHODS: In this prospective cohort study of 109 patients with genetically documented HD, aged 21 to 85 years, we determined fasting blood levels of total IGFI, GH, and insulinlike factor binding protein 3 at baseline, and we used the cognitive Unified Huntington's Disease Rating Scale to assess cognitive impairment at baseline and for up to 5 years subsequently. Associations were evaluated using mixed linear model analysis. RESULTS: Higher plasma IGFI concentrations were associated with greater cognitive decline (beta Stroop Words, -6.01, p = 0.003; beta Stroop Color, -4.41, p = 0.01; beta Stroop Color/Words, -3.86, p = 0.02; beta Symbol Digit Modalities, -3.69, p = 0.03; and beta verbal fluency, -5.01, p = 0.03). Higher free IGFI concentrations and higher GH concentrations in men also predicted greater cognitive decline. CONCLUSIONS: Our findings in patients with HD suggest that a high IGFI level at baseline may be associated with greater subsequent declines in executive function and attention.

[Presentation of an assessment battery for visual mental imagery and visual perception]. / Normalisation d'une batterie d'évaluation de l'imagerie mentale visuelle et de la perception visuelle.

INTRODUCTION: The relationship between visual perception and visual mental imagery are at the center of a lively theoretical debate between those postulating common neurocognitive processes between perception and imagery and those who emphasize the differences between these two entities. Neuropsychology can make an important contribution to this debate, by assessing associations and dissociations between perceptual and imaginal deficits in patients with brain damage. However, currently there is no standardized test battery available for such assessments. MATERIAL AND METHODS: Here we present a battery of paper-and-pencil tests assessing different domains of visual mental imagery and visual perception abilities: object form and color, animals, orthographic material, numbers, faces, and space. We also explored the effects of age, educational level and gender on performance on a group of 103 participants free of neurological damage. RESULTS: The battery includes two parts: one composed of 14 tests assessing mental imagery and the second part composed of eight tests assessing the abilities of visual perception. We calculated the correlations between the tests, and found that, with the exception of orthographic material, there were generally poor correlations between imagery and perceptual tests. CONCLUSION: This result seems inconsistent with hypotheses postulating a strict correspondence between perceptual and imagery abilities.

Quantum scattering of neon from a nanotextured surface.

Phonon exchange is the usual cause of decoherence in atom-surface scattering. By including quantum effects in the treatment of Debye-Waller scattering, we show that phonon exchange becomes ineffective when the relevant phonon frequencies are high. The result explains the surprising observation of strong elastic scattering of Ne from a Cu(100) surface nanotextured with a c(2 × 2) Li adsorbate structure. We extend a previous model to describe the phonon spectra by an Einstein oscillator component with an admixture of a Debye spectrum. The Einstein oscillator represents the dominant, high frequency vibration of the adsorbate, normal to the surface, while the Debye spectrum represents the substrate contribution. Neon scattering is so slow that exciting the adsorbate mode has a low probability and is impossible if the incident energy is below the threshold. Thus, adsorbate vibrations are averaged out. A theoretical discussion and calculation shows that under such circumstances the vibrations of a light adsorbate do not contribute to the Debye-Waller effect, with the result that Ne scattering at thermal energies is quantum mechanical and largely elastic, explaining the high reflectivity and the diffraction peaks observed experimentally.

Coverage-dependent quantum versus classical scattering of thermal neon atoms from Li/Cu(100).

We show that subtle variations in surface structure can enhance quantum scattering and quench atom-surface energy transfer. The scattering of thermal energy neon atoms from a lithium overlayer on a copper substrate switches between a classical regime, dominated by multiphonon interactions, and a quantum regime, dominated by elastic diffraction. The transition is achieved by simple tailoring of the lithium coverage and quantum scattering dominates only in the narrow coverage range of theta=0.3-0.6 ML. The results are described qualitatively using a modified Debye-Waller model that incorporates an approximate quantum treatment of the adsorbate-substrate vibration.

Striatal degeneration impairs language learning: evidence from Huntington's disease.

Although the role of the striatum in language processing is still largely unclear, a number of recent proposals have outlined its specific contribution. Different studies report evidence converging to a picture where the striatum may be involved in those aspects of rule-application requiring non-automatized behaviour. This is the main characteristic of the earliest phases of language acquisition that require the online detection of distant dependencies and the creation of syntactic categories by means of rule learning. Learning of sequences and categorization processes in non-language domains has been known to require striatal recruitment. Thus, we hypothesized that the striatum should play a prominent role in the extraction of rules in learning a language. We studied 13 pre-symptomatic gene-carriers and 22 early stage patients of Huntington's disease (pre-HD), both characterized by a progressive degeneration of the striatum and 21 late stage patients Huntington's disease (18 stage II, two stage III and one stage IV) where cortical degeneration accompanies striatal degeneration. When presented with a simplified artificial language where words and rules could be extracted, early stage Huntington's disease patients (stage I) were impaired in the learning test, demonstrating a greater impairment in rule than word learning compared to the 20 age- and education-matched controls. Huntington's disease patients at later stages were impaired both on word and rule learning. While spared in their overall performance, gene-carriers having learned a set of abstract artificial language rules were then impaired in the transfer of those rules to similar artificial language structures. The correlation analyses among several neuropsychological tests assessing executive function showed that rule learning correlated with tests requiring working memory and attentional control, while word learning correlated with a test involving episodic memory. These learning impairments significantly correlated with the bicaudate ratio. The overall results support striatal involvement in rule extraction from speech and suggest that language acquisition requires several aspects of memory and executive functions for word and rule learning.

Progress and prospects: gene therapy clinical trials (part 2).

This is the second part of a review summarizing progress and prospects in gene therapy clinical research. Twenty key diseases/strategies are succinctly described and commented on by leaders in the field. This part includes clinical trials for skin diseases, neurological disorders, HIV/AIDS, ornithine transcarbamylase deficiency, alpha(1)-antitrypsin deficiency, haemophilia and cancer.

Biological abnormalities of peripheral A(2A) receptors in a large representation of polyglutamine disorders and Huntington's disease stages.

Huntington's disease is one of a group of hereditary neurodegenerative diseases characterized by a glutamine expansion (polyQ) in proteins which are expressed in various cell populations. In agreement with this widespread distribution, we have previously shown that A(2A) receptor signaling is affected in mouse brain as well as in peripheral blood cells from a small cohort of HD patients. Here we analyzed a total of 252 subjects, including 126 HD gene-positive individuals, from different clinical sites. Consistent with our previous data we show that A(2A) receptor B(max) values are robustly increased at all HD stages as well as in 32 pre-symptomatic subjects. We report that the same abnormality is present also in other polyQ but not in non-polyQ inherited neurological disorders. Finally, we demonstrate that the same peripheral cells exhibit an altered membrane fluidity, a finding that may explain the observed change in receptor density. We argue that the observed alteration in lymphocytes reflects the presence of the mutant protein, and we suggest that the measure of the A(2A) receptor binding activity might be of potential interest for a peripheral assessment of chemicals capable of interfering with the immediate toxic effects of the mutation.

Distribution of grey matter atrophy in Huntington's disease patients: a combined ROI-based and voxel-based morphometric study.

The striatum, a subcortical structure, is the principal target of the neurodegenerative process in Huntington's disease (HD). The measurement of striatal atrophy using the bicaudate ratio on CT scanner images has therefore been used for years to assess disease progression, but this measure only takes into account unidimensional changes in the head of the caudate nucleus. Recently, voxel-based morphometry (VBM), which permits automated statistical comparisons of whole-brain MRI images, has been proposed to quantify striatal atrophy. However, VBM was not originally designed to study subcortical structures, and severe deep brain deformations that occur in HD may hamper the automatic processing of VBM. Here, we validate the use of the optimised protocol of VBM to quantify subcortical atrophy in HD by comparing results obtained with this method to those provided by manual segmentation of subcortical structures. We studied 20 patients with early HD and 12 controls matched for age, sex and handedness using an improved T1-weighted sequence that eased grey matter segmentation. Both manual and automated methods evidenced the dorso-ventral gradient of striatal atrophy, a loss of grey matter in the globus pallidus and the thalamus, and similar correlations between clinical scores and subcortical atrophy. Furthermore, we were able to detect with VBM grey matter loss in the substantia nigra, the hypothalamus, the amygdala, the insular cortex and the premotor and sensorimotor cortices. Finally, VBM provided results consistent with previous post mortem results and proved to be a sensitive biomarker capable of correctly managing subcortical distortions throughout HD patients' brains.

[French adaptation of the Hopkins Verbal Learning Test]. / Adaptation française du <>.

INTRODUCTION: A number of tests are currently used in clinical and research settings for the assessment of patients with memory deficits. Among them, the Hopkins Verbal Learning Test (HVLT) is particularly appropriate for the longitudinal follow-up of patients with memory disorders because it exists in six parallel forms, and therefore avoids the risk of learning effect at retest. Since a test with these characteristics is not available in French, we decided to adapt a French version of the HVLT. METHODS: 180 normal subjects participated in the study. Their mean age was 41 years (SD=11), and they had had on average 12 years of schooling (SD=3). The subjects were randomly divided into 6 groups of 30 subjects. One of the six forms of the French version of the HVLT was administered orally to each group of subjects. Each form consisted of a list of 12 words belonging to 3 different semantic categories. For the construction of the French version of the HVLT, we adopted the same procedure as used in the original version of the test taking into account the French lexical and semantic characteristics of the items. In the first part of the test, the list was administered three times to the subjects. Following each administration, subjects were asked for an immediate free recall. Twenty minutes later, used for intercurrent tasks, subjects were asked for a delayed free recall, which was immediately followed by a recognition memory task. In this task, subjects listened to a list of 24 words, 12 belonging to the studied list and 12 were distractors; the subjects were asked to recognize the 12 studied words. RESULTS: The subjects' performance was equivalent in the six forms of the test, except for the immediate recall of Form 3 (which was excluded from the test). No significant difference emerged in free recall, delayed free recall, and recognition across the five remaining forms of the test. CONCLUSION: Our study provides a useful tool for the longitudinal evaluation of patients with memory impairment and may become the test of reference in European longitudinal clinical trials. The French adaptation of the HVLT represents only a first step, because it needs to be standardized, in order to provide norms, and validated, in order to provide values of sensitivity and specificity.