Differences in Protein Capture by SP3 and SP4 Demonstrate Mechanistic Insights of Proteomics Clean-up Techniques.

The goal of proteomics experiments is to identify proteins to observe changes in cellular processes and diseases. One challenge in proteomics is the removal of contaminants following protein extraction, which can limit protein identification. Single-pot, solid-phase-enhanced sample preparation (SP3) is a clean-up technique in which proteins are captured on carboxylate-modified particles through a proposed hydrophilic-interaction-liquid-chromatography (HILIC)-like mechanism. However, recent results have suggested that proteins are captured in SP3 due to a protein-aggregation mechanism. Thus, solvent precipitation, single-pot, solid-phase-enhanced sample preparation (SP4) is a newer clean-up technique that employs protein-aggregation to capture proteins without modified particles. SP4 has previously enriched low-solubility proteins, though differences in protein capture could affect which proteins are detected and identified. We hypothesize that the mechanisms of capture for SP3 and SP4 are distinct. Herein, we assess the proteins identified and enriched using SP3 versus SP4 for MCF7 subcellular fractions and correlate protein capture in each method to protein hydrophobicity. Our results indicate that SP3 captures more hydrophilic proteins through a combination of HILIC-like and protein-aggregation mechanisms, while SP4 captures more hydrophobic proteins through a protein-aggregation mechanism. From these results, we recommend clean-up techniques based on protein-sample hydrophobicity to yield high proteome coverage in biological samples.

Gas-phase stability and thermodynamics of ligand-bound, binary complexes of chloramphenicol acetyltransferase reveal negative cooperativity.

The biological role of the bacterial chloramphenicol (Chl)-resistance enzyme, chloramphenicol acetyltransferase (CAT), has seen renewed interest due to the resurgent use of Chl against multi-drug-resistant microbes. This looming threat calls for more rationally designed antibiotic derivatives that have improved antimicrobial properties and reduced toxicity in humans. Herein, we utilize native ion mobility spectrometry-mass spectrometry (IMS-MS) to investigate the gas-phase structure and thermodynamic stability of the type I variant of CAT from Escherichia coli (EcCATI) and several EcCATI:ligand-bound complexes. EcCATI readily binds multiple Chl without incurring significant changes to its gas-phase structure or stability. A non-hydrolyzable acetyl-CoA derivative (S-ethyl-CoA, S-Et-CoA) was used to kinetically trap EcCATI and Chl in a ternary, ligand-bound state (EcCATI:S-Et-CoA:Chl). Using collision-induced unfolding (CIU)-IMS-MS, we find that Chl dissociates from EcCATI:S-Et-CoA:Chl complexes at low collision energies, while S-Et-CoA remains bound to EcCATI even as protein unfolding occurs. Gas-phase binding constants further suggest that EcCATI binds S-Et-CoA more tightly than Chl. Both ligands exhibit negative cooperativity of subsequent ligand binding in their respective binary complexes. While we observe no significant change in structure or stability to EcCATI when bound to either or both ligands, we have elucidated novel gas-phase unfolding and dissociation behavior and provided a foundation for further characterization of alternative substrates and/or inhibitors of EcCATI.

Cognitive and psychological outcomes and follow-up in severely affected COVID-19 survivors admitted to a rehabilitation hospital.

BACKGROUND: The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) represents the most recent severe pandemic resulting in coronavirus disease 2019 (COVID-19). COVID-19 can damage the central nervous system, requiring admission to intensive care units (ICU) and aggressive treatments (long-term ventilatory assistance and sedation) to stabilize vitals. Most post-COVID-19 patients experience cognitive impairments and mood or stress disorders. We aimed to study the frequency of cognitive deficits in COVID-19 survivors, the relationship between clinical factors in the acute phase and cognitive outcomes, affective states, and quality of life. We explored cognitive reserve (CR) role, as a post-COVID-19 resilience factor. METHODS: Twenty-nine COVID-19 inpatients were assessed using a neuropsychological battery, mood scales, quality of life, and social integration questionnaires. Twenty-five were retained through telephone follow-up to monitor cognitive sequelae, affective states, and reintegration levels roughly 8 months after hospital discharge. We administered the Cognitive Reserve Index questionnaire. RESULTS: We found most patients display no cognitive deficits. When they did, multi-domain impairment occurred most frequently, especially involving executive functions. Results revealed a significant correlation between depression levels and the interval between ICU admission and tracheal tube removal. We found increased levels of depression and anxiety at follow-up, a significant relationship between resuming daily life activities, high CR, and executive functions. CONCLUSIONS: These findings suggest the importance of psychological support in the long term and the modulating role of cognitive reserve in quality of life after infection.

Cognition in COVID-19 infected patients undergoing invasive ventilation: results from a multicenter retrospective study.

A growing number of scientific contributions suggest that COVID-19 infection can lead to impairment of cognition, mainly in executive functions and memory domains, even in the absence of frank neurological pathologies.The primary objective of this retrospective study is to evaluate the frequency and type of inefficiencies in a selection of cognitive tests administered to a sample of subjects who, following infection, required invasive assisted ventilation and were admitted to rehabilitation wards for the treatment of functional impairment.Fifty-seven subjects were enrolled. The recruited patients undergone an assessment of verbal and visuospatial memory and executive functions, upon entry into the rehabilitation department, after discharge from intensive care. The following tests were administered: Rey Auditory Verbal Learning Test (AVLT) (immediate and delayed recall), Rey-Osterrieth Complex Figure Test (ROCFT) (copy and delayed recall), Stroop Color-Word Test, and Trail Making Test (TMT, A and B).Deficient scores, in beyond 25% of subjects, were found in the copy of the ROCFT (32.1% of subjects), and in the delayed recall of ROCFT (27.2%). Between 10 and 20% of patients presented an abnormal result in delayed recall of AVLT (16.07%), and Stroop Test (time, 15.6%, error, 11.5%). Less than 10% of the sample had abnormal performances on TMT (A, 3.5%, and B, 9.4%), and in AVLT immediate recall (8.9%). Correlations of the performances with age, sex, and education were also found.This paper highlights the high incidence of abnormal cognitive performances in this specific subpopulation of patients with COVID-19 infection.

Dilithium Amides as a Modular Bis-Anionic Ligand Platform for Iron-Catalyzed Cross-Coupling.

Dilithium amides have been developed as a bespoke and general ligand for iron-catalyzed Kumada-Tamao-Corriu cross-coupling reactions, their design taking inspiration from previous mechanistic and structural studies. They allow for the cross-coupling of alkyl Grignard reagents with sp2-hybridized electrophiles as well as aryl Grignard reagents with sp3-hybridized electrophiles. This represents a rare example of a single iron-catalyzed system effective across diverse coupling reactions without significant modification of the catalytic protocol, as well as remaining operationally simple.

'Less is more': validation with Rasch analysis of five short-forms for the Brain Injury Rehabilitation Trust Personality Questionnaires (BIRT-PQs).

BACKGROUND: Previous analyses demonstrated a lack of unidimensionality, item redundancy, and substantial administrative burden for the Brain Injury Rehabilitation Trust Personality Questionnaires (BIRT-PQs). OBJECTIVE: To use Rasch Analysis to calibrate five short-forms of the BIRT-PQs, satisfying the Rasch model requirements. METHODS: BIRT-PQs data from 154 patients with severe Acquired Brain Injury (s-ABI) and their caregivers (total sample = 308) underwent Rasch analysis to examine their internal construct validity and reliability according to the Rasch model. RESULTS: The base Rasch analyses did not show sufficient internal construct validity according to the Rasch model for all five BIRT-PQs. After rescoring 18 items, and deleting 75 of 150 items, adequate internal construct validity was achieved for all five BIRT-PQs short forms (model chi-square p-values ranging from 0.0053 to 0.6675), with reliability values compatible with individual measurements. CONCLUSIONS: After extensive modifications, including a 48% reduction of the item load, we obtained five short forms of the BIRT-PQs satisfying the strict measurement requirements of the Rasch model. The ordinal-to-interval measurement conversion tables allow measuring on the same metric the perception of the neurobehavioral disability for both patients with s-ABI and their caregivers.

The unidimensionality of the five Brain Injury Rehabilitation Trust Personality Questionnaires (BIRT-PQs) may be improved: preliminary evidence from classical psychometrics.

Objective: To assess the internal construct validity (ICV) of the five Brain Injury Rehabilitation Trust Personality Questionnaires (BIRT-PQ) with Classical Test Theory methods.Methods: Multicenter cross-sectional study involving 11 Italian rehabilitation centers. BIRT-PQs were administered to patients with severe Acquired Brain Injury and their respective caregivers. ICV was assessed by the mean of an internal consistency analysis (ICA) and a Confirmatory Factor Analysis (CFA).Results: Data from 154 patients and their respective caregivers were pooled, giving a total sample of 308 subjects. Despite good overall values (alphas ranging from 0.811 to 0.937), the ICA revealed that several items within each scale did not contribute as expected to the total score. This result was confirmed by the CFA, which showed the misfit of the data to a unidimensional model (RMSEA ranging from 0.077 to 0.097). However, after accounting for local dependency found within the data, fitness to a unidimensional model improved significantly (RMSEA ranging from 0.050 to 0.062).Conclusion: Despite some limitations, our analyses demonstrated the lack of ICV for the BIRT-PQ total scores. It is envisaged that a more comprehensive ICV analysis will be performed with Rasch analysis, aiming to improve both the measurement properties and the administrative burden of each BIRT-PQ.

Safe return to driving following severe acquired brain injury: role of a short neuropsychological assessment.

BACKGROUND: Driving is a complex ability requiring a broad range of motor, cognitive-behavioral and visual skills that may be impaired after severe acquired brain injury (sABI). Resumption of driving is perceived as a major need by patients, being closely linked to personal autonomy, work and social activities. AIM: The objective of this study was to identify a short battery of neuropsychological tests with predictive value with regard to safe return to driving after sABI. DESIGN: Observational study. SETTING: Outpatient of a rehabilitation center for sABI. POPULATION: A continuous series of 127 patients with stable sABI, well-reintegrated at a family and social level, dismissed since at least one year from the end of their intensive rehabilitation, enrolled between 2006 and 2014. METHODS: Patients underwent an extensive battery of neuropsychological tests (pencil and paper and specific PC programs), aimed at assessing cognitive functions, in performance and verbal tasks. The results were analyzed in relation to their on-road performance during the driving test conducted by the office of the Italian Government Authority (success or failure of the test). RESULTS: No correlations were found between demographic data, etiology, driving experience, verbal competence and the decision of the competent authority. Significant correlation was found between attention, executive functions, overall visual-spatial exploration and driving performance. CONCLUSIONS: Both "pencil and paper" and computerized tests in the cognitive domains of attentive functions, and those involving performance with visual-spatial material, are significantly correlated with the driving test outcome, even if there is not enough evidence of the relative value of off-road compared to direct on-road tests. CLINICAL REHABILITATION IMPACT: We propose a small neuropsychological battery of tests with normative data for Italian population, predictive with respect to the ability to drive safely. We recommend to use it as first screening before submitting patients to more demanding and risky on-road driving tests.

The impact of biological sex and sex hormones on cognition in a rat model of early, pre-motor Parkinson's disease.

Parkinson's disease (PD) is well known for motor deficits such as bradykinesia. However, patients often experience additional deficits in working memory, behavioral selection, decision-making and other executive functions. Like other features of PD, the incidence and severity of these cognitive symptoms differ in males and females. However, preclinical models have not been used to systematically investigate the roles that sex or sex hormones may play in these complex signs. To address this, we used a Barnes maze spatial memory paradigm to compare the effects of a bilateral nigrostriatal dopamine lesion model of early PD on cognitive behaviors in adult male and female rats and in adult male rats that were gonadectomized or gonadectomized and supplemented with testosterone or estradiol. We found that dopamine lesions produced deficits in working memory and other executive operations, albeit only in male rats where circulating androgen levels were physiological. In males where androgen levels were depleted, lesions produced no additional Barnes maze deficits and attenuated those previously linked to androgen deprivation. We also found that while most measures of Barnes maze performance were unaffected by dopamine lesions in the females, lesions did induce dramatic shifts from their preferred use of thigmotactic navigation to the use of spatially guided place strategies similar to those normally preferred by males. These and other sex- and sex hormone-specific differences in the effects of nigrostriatal dopamine lesions on executive function highlight the potential of gonadal steroids as protective and/or therapeutic for the cognitive symptoms of PD. However, their complexity also indicates the need for a more thorough understanding of androgen and estrogen effects in guiding the development of hormone therapies that might effectively address these non-motor signs.

¿Existen patrones diferentes de asimetría cerebral entre subtipos disléxicos? / Are there different patterns of cerebral asymmetry between dyslexic subtypes?

El objetivo de este estudio fue analizar la asimetría cerebral en niños disléxicos y, específicamente, comprobar si existen diferencias en asimetría cerebral entre subtipos disléxicos. Para ello se seleccionó una muestra de 89 disléxicos de la que se identificaron subtipos disléxicos mediante el método de regresión estadística a partir del trabajo de Jiménez y Ramírez (2002). La técnica utilizada para evaluar las diferencias funcionales hemisféricas fue la de tareas concurrentes. Los datos encontrados fueron comparados con los mostrados por un grupo control de lectores normales equiparados en edad cronológica (EC) al grupo experimental (N= 37) y con los evidenciados por un grupo control de niños lectores normales (NL) pero de menor edad cronológica que el grupo experimental (N= 40). Se encontró que, a diferencia del grupo control de igual edad cronológica, en el grupo de disléxicos hubo un elevado porcentaje de niños que mostró un patrón de convergencia en el hemisferio izquierdo tanto para las funciones verbales como para las espaciales. Este mismo resultado fue obtenido en el grupo de lectores normales de menor edad. Por otra parte, no se encontraron patrones diferentes de asimetría cerebral entre los subtipos disléxicos identificados

The purpose of this research has been to analyze the cerebral asymmetry in dyslexic children and, specifically for demonstrating whether there are different patterns of cerebral asymmetry among subtypes of dyslexia. We used a sample of 89 dyslexic children divided into subtypes obtained from the Jimenez and Ramirez (2002) study. The dual-task method was used to assess hemispheric specialization. The data were compared with that obtained from a control group of normal readers of same age (CA; N= 37) and with a younger reading level control group (RL; N= 40). We found that in the dyslexic group, similarly to the younger reading level group, a high percentage of children showed convergence in the left hemisphere of both linguistic and spatial functions. This pattern was also found in the RL control group. On the other hand, we did not find different patterns of cerebral asymmetry between dyslexic subtypes

[Are there different patterns of cerebral asymmetry between dyslexic subtypes? ]. / Existen patrones diferentes de asimetría cerebral entre subtipos disléxicos?

The purpose of this research has been to analyze the cerebral asymmetry in dyslexic children and, specifically for demonstrating whether there are different patterns of cerebral asymmetry among subtypes of dyslexia. We used a sample of 89 dyslexic children divided into subtypes obtained from the Jimenez and Ramirez (2002) study. The dual-task method was used to assess hemispheric specialization. The data were compared with that obtained from a control group of normal readers of same age (CA; N= 37) and with a younger reading level control group (RL; N= 40). We found that in the dyslexic group, similarly to the younger reading level group, a high percentage of children showed convergence in the left hemisphere of both linguistic and spatial functions. This pattern was also found in the RL control group. On the other hand, we did not find different patterns of cerebral asymmetry between dyslexic subtypes.