Essential Functional Interplay of the Catalytic Groups in Acid Phosphatase.

The cooperative interplay between the functional devices of a preorganized active site is fundamental to enzyme catalysis. An in-depth understanding of this phenomenon is central to elucidating the remarkable efficiency of natural enzymes and provides an essential benchmark for enzyme design and engineering. Here, we study the functional interconnectedness of the catalytic nucleophile (His18) in an acid phosphatase by analyzing the consequences of its replacement with aspartate. We present crystallographic, biochemical, and computational evidence for a conserved mechanistic pathway via a phospho-enzyme intermediate on Asp18. Linear free-energy relationships for phosphoryl transfer from phosphomonoester substrates to His18/Asp18 provide evidence for the cooperative interplay between the nucleophilic and general-acid catalytic groups in the wild-type enzyme, and its substantial loss in the H18D variant. As an isolated factor of phosphatase efficiency, the advantage of a histidine compared to an aspartate nucleophile is ∼104-fold. Cooperativity with the catalytic acid adds ≥102-fold to that advantage. Empirical valence bond simulations of phosphoryl transfer from glucose 1-phosphate to His and Asp in the enzyme explain the loss of activity of the Asp18 enzyme through a combination of impaired substrate positioning in the Michaelis complex, as well as a shift from early to late protonation of the leaving group in the H18D variant. The evidence presented furthermore suggests that the cooperative nature of catalysis distinguishes the enzymatic reaction from the corresponding reaction in solution and is enabled by the electrostatic preorganization of the active site. Our results reveal sophisticated discrimination in multifunctional catalysis of a highly proficient phosphatase active site.

The N-terminal Helix-Turn-Helix Motif of Transcription Factors MarA and Rob Drives DNA Recognition.

DNA-binding proteins play an important role in gene regulation and cellular function. The transcription factors MarA and Rob are two homologous members of the AraC/XylS family that regulate multidrug resistance. They share a common DNA-binding domain, and Rob possesses an additional C-terminal domain that permits binding of low-molecular weight effectors. Both proteins possess two helix-turn-helix (HTH) motifs capable of binding DNA; however, while MarA interacts with its promoter through both HTH-motifs, prior studies indicate that Rob binding to DNA via a single HTH-motif is sufficient for tight binding. In the present work, we perform microsecond time scale all-atom simulations of the binding of both transcription factors to different DNA sequences to understand the determinants of DNA recognition and binding. Our simulations characterize sequence-dependent changes in dynamical behavior upon DNA binding, showcasing the role of Arg40 of the N-terminal HTH-motif in allowing for specific tight binding. Finally, our simulations demonstrate that an acidic C-terminal loop of Rob can control the DNA binding mode, facilitating interconversion between the distinct DNA binding modes observed in MarA and Rob. In doing so, we provide detailed molecular insight into DNA binding and recognition by these proteins, which in turn is an important step toward the efficient design of antivirulence agents that target these proteins.

Migration of Junior Doctors: The Case of Psychiatric Trainees in Portugal.

INTRODUCTION: In the last few decades, the rates of international medical migration have continuously risen. In Psychiatry, there is great disparity in the workforce between high and low-income countries. Yet, little is known about the 'push' and 'pull' factors and the migratory intentions of trainees. This study aims to assess the factors impacting the decisions of psychiatric trainees in Portugal towards migration. MATERIAL AND METHODS: A questionnaire was developed in the Brain Drain study and was distributed to psychiatric trainees in Portugal. RESULTS: The sample consists of 104 psychiatric trainees (60.6% female). Overall, 40.4% of the trainees had prior experience of living abroad and the majority (96.9%) felt that this experience influenced their attitude towards migration in a positive way. About 75% of trainees had 'ever' considered leaving the country, but the majority (70.0%) had not taken any 'practical steps' towards migration. The main reasons to stay in Portugal were personal, while the main reason to leave was financial. The majority of the trainees (55.7%) were dissatisfied or very dissatisfied with their income, working conditions and academic opportunities. DISCUSSION: Working conditions, salaries and academic opportunities are the main triggers for the migration of psychiatric trainees from Portugal. CONCLUSION: These results may inform the decisions of stakeholders in the health and education sectors and point out the necessary investments required and the impact it may have on the workforce.

Introdução: Nas últimas décadas, a migração médica internacional tem aumentado continuamente. Na Psiquiatria, existe uma grande disparidade de recursos humanos entre países desenvolvidos e com baixo desenvolvimento económico. No entanto, pouco se sabe sobre os fatores que atraem (push) ou afastam (pull) a mobilidade e quais as intenções migratórias dos internos de psiquiatria. O objetivo deste estudo é avaliar os fatores que influenciam o processo de tomada de decisão dos internos de Psiquiatria em Portugal relativamente à migração. Material e Métodos: Um questionário foi desenvolvido no âmbito do estudo Brain Drain, e foi enviado aos internos de Psiquiatria em Portugal. Resultados: A amostra é constituída por 104 internos de Psiquiatria (60,6% do sexo feminino). No geral, 40,4% dos internos tiveram uma experiência de mobilidade e a maioria (96,9%) sentiu que esta os influenciou positivamente na sua atitude em relação à migração. Cerca de 75% dos internos já considerou emigrar, mas a maioria (70,0%) não deu nenhum passo nessa direção. A principal razão para permanecer no país prende-se com factores pessoais, enquanto o principal motivo para emigrar é financeiro. A maioria (55,7%) dos internos estava insatisfeito ou muito insatisfeito com o seu salário, condições de trabalho e oportunidades académicas. Discussão: Condições de trabalho, salários e oportunidades académicas são os principais estímulos para a emigração nos internos de Psiquiatria em Portugal. Conclusão: Estes resultados poderão apoiar a tomada de decisão dos decisores em saúde e educação médica sobre os investimentos necessários e a sua influência na força laboral futura.

Social cognition and interaction training for recent-onset schizophrenia: A preliminary randomized trial.

Comprehensive social cognition training programs have been effective to improve social cognition in people with chronic schizophrenia, although there is insufficient quality evidence for recent-onset psychosis. The aim of this study was to assess the effects of Social Cognition and Interaction Training (SCIT) in a sample of recent-onset schizophrenia outpatients. Sixteen participants who had their first psychotic episode for less than 2 years were randomly allocated to the SCIT group during 20 weeks (weekly sessions) or to a psychoeducation group and completed baseline and post-training assessment for cognitive biases, social cognition, clinical symptoms and functioning. Permutation-based analysis revealed improvements in overall functioning (P = 0.036) and blame score (P = 0.070) in the SCIT group compared to the psychoeducation intervention, with large effect sizes (d = 1.438 and d = 1.204, respectively). There were also large effect sizes for hostility, emotion recognition, social perception, positive and total symptoms (d = 0.833-1.158). These results suggest that SCIT may be an effective tool to improve attributional biases and functional outcomes in recent-onset schizophrenia outpatients. Future controlled trials with larger sample size and follow-up assessments should be developed to further understand effective intervention outcomes for this population.

Recent Advances in Understanding Biological GTP Hydrolysis through Molecular Simulation.

GTP hydrolysis is central to biology, being involved in regulating a wide range of cellular processes. However, the mechanisms by which GTPases hydrolyze this critical reaction remain controversial, with multiple mechanistic possibilities having been proposed based on analysis of experimental and computational data. In this mini-review, we discuss advances in our understanding of biological GTP hydrolysis based on recent computational studies and argue in favor of solvent-assisted hydrolysis as a conserved mechanism among GTPases. A concrete understanding of the fundamental mechanisms by which these enzymes facilitate GTP hydrolysis will have significant impact both for drug discovery efforts and for unraveling the role of oncogenic mutations.

The role of ligand-gated conformational changes in enzyme catalysis.

Structural and biochemical studies on diverse enzymes have highlighted the importance of ligand-gated conformational changes in enzyme catalysis, where the intrinsic binding energy of the common phosphoryl group of their substrates is used to drive energetically unfavorable conformational changes in catalytic loops, from inactive open to catalytically competent closed conformations. However, computational studies have historically been unable to capture the activating role of these conformational changes. Here, we discuss recent experimental and computational studies, which can remarkably pinpoint the role of ligand-gated conformational changes in enzyme catalysis, even when not modeling the loop dynamics explicitly. Finally, through our joint analyses of these data, we demonstrate how the synergy between theory and experiment is crucial for furthering our understanding of enzyme catalysis.

Pink- and orange-pigmented Planctomycetes produce saproxanthin-type carotenoids including a rare C45 carotenoid.

Planctomycetes are ubiquitous and environmentally important Gram-negative aquatic bacteria with key roles in global carbon and nitrogen cycles. Many planctomycetal species have a pink or orange colour and have been suggested to produce carotenoids. Potential applications as food colorants or anti-oxidants have been proposed. Hitherto, the planctomycetal metabolism is largely unexplored and the strain pigmentation has not been explored. For a holistic view of the complex planctomycetal physiology, we analysed carotenoid profiles of the pink-pigmented strain Rhodopirellula rubra LF2T and of the orange strain Rubinisphaera brasiliensis Gr7. During LC-MS/MS analysis of culture extracts, we could identify three saproxanthin-type carotenoids including a rare C45 carotenoid. These compounds, saproxanthin, dehydroflexixanthin and 2'-isopentenyldehydrosaproxanthin, derive from the common carotenoid precursor lycopene and are characterized by related end groups, namely a 3-hydroxylated ß-carotene-like cyclohexene ring as one end group and simple hydration on the other end of the molecule. Based on the observed molecule structure we present putative pathways for their biosynthesis. Results support Planctomycetes as a promising, yet mostly untapped source of carotenoids.

GTP Hydrolysis Without an Active Site Base: A Unifying Mechanism for Ras and Related GTPases.

GTP hydrolysis is a biologically crucial reaction, being involved in regulating almost all cellular processes. As a result, the enzymes that catalyze this reaction are among the most important drug targets. Despite their vital importance and decades of substantial research effort, the fundamental mechanism of enzyme-catalyzed GTP hydrolysis by GTPases remains highly controversial. Specifically, how do these regulatory proteins hydrolyze GTP without an obvious general base in the active site to activate the water molecule for nucleophilic attack? To answer this question, we perform empirical valence bond simulations of GTPase-catalyzed GTP hydrolysis, comparing solvent- and substrate-assisted pathways in three distinct GTPases, Ras, Rab, and the Gαi subunit of a heterotrimeric G-protein, both in the presence and in the absence of the corresponding GTPase activating proteins. Our results demonstrate that a general base is not needed in the active site, as the preferred mechanism for GTP hydrolysis is a conserved solvent-assisted pathway. This pathway involves the rate-limiting nucleophilic attack of a water molecule, leading to a short-lived intermediate that tautomerizes to form H2PO4- and GDP as the final products. Our fundamental biochemical insight into the enzymatic regulation of GTP hydrolysis not only resolves a decades-old mechanistic controversy but also has high relevance for drug discovery efforts. That is, revisiting the role of oncogenic mutants with respect to our mechanistic findings would pave the way for a new starting point to discover drugs for (so far) "undruggable" GTPases like Ras.

Anxiety, Depression and Academic Performance: A Study Amongst Portuguese Medical Students Versus Non-Medical Students.

INTRODUCTION: The aim of the study is to assess the prevalence of anxiety and depressive symptoms in Portuguese medical students compared to students of other faculties, and the possible impact those symptoms have on academic performance. MATERIAL AND METHODS: A cross-sectional study was conducted in a sample of 750 students: 512 medical students and 238 nonmedical students. All students anonymously completed a socio-demographic survey and the Hospital Anxiety and Depression Scale (HADS). Statistical analysis was performed using the chi-square test, Mann-Whitney test, Spearman correlation coefficient or Kruskal-Wallis test. RESULTS: We found a prevalence of 21.5% (n = 161) for anxiety symptoms and 3.7% (n = 28) for depressive symptoms. Being a medical student was more significantly associated with symptoms of anxiety (p = 0.034) compared with other students. Depressive symptoms were slightly associated with poor academic performance (p < 0.01). A percentage of 59.6% (n = 96) of students with anxiety symptoms and 46.4% (n = 13) of students with depressive symptoms did not seek medical or psychological care at that time. DISCUSSION: Medical students in this sample seem to have more symptoms of anxiety, possibly explained by a higher number of female students in that sample. Depressive symptoms could be associated with poor academic performance in both groups, but an evident correlation was not established. CONCLUSION: Considering the high levels of anxiety symptoms, the possible impact of depressive symptoms in academic performance and the lack of psychiatric or psychological follow-up reported in this study, it is urgent to develop adequate means of support to improve students' well-being and mental health.

Introdução: Este estudo avalia a prevalência da sintomatologia de ansiedade e depressão em estudantes portugueses de Medicina versus estudantes de outros cursos e uma eventual associação destes sintomas com alterações na performance académica. Material e Métodos: Realizou-se um estudo transversal com 750 alunos: 512 de Medicina e 238 de outros cursos. Todos preencheram anonimamente um questionário sócio-demográfico e a escala Hospital Anxiety and Depression Scale (HADS). A análise estatística foi efetuada utilizando o teste qui-quadrado, teste de Mann-Whitney, correlação de Spearman ou teste de Kruskal-Wallis. Resultados: Observou-se uma prevalência de sintomas ansiosos de 21,5% (n = 161) e de sintomas depressivos de 3,7% (n = 28). Os alunos de Medicina estiveram mais significativamente associados a sintomas ansiosos (p = 0,034) comparado com alunos de outros cursos. Os sintomas depressivos parecem estar mais associados a má performance académica (p < 0,01). 59,6% (n = 96) dos alunos com sintomatologia ansiosa ou e 46,4% (n=13) dos alunos com sintomas depressivos não recebeu acompanhamento psicológico ou psiquiátrico até à data. Discussão: Os alunos de Medicina desta amostra têm maior taxa de sintomas ansiosos, possivelmente relacionado com um maior número de estudantes do sexo feminino nesse subgrupo. Os sintomas depressivos poderão afetar negativamente a performance académica de todos os estudantes, mas não foi estabelecida uma correlação evidente entre estes dois fatores. Conclusão: Dada a elevada taxa de sintomas de ansiedade, o eventual impacto dos sintomas depressivos a nível académico e a falta de acompanhamento especializado reportada nesta amostra, é urgente criar meios adequados de apoio aos estudantes no sentido de melhorar o seu bem-estar e saúde mental.

Molecular motion regulates the activity of the Mitochondrial Serine Protease HtrA2.

HtrA2 (high-temperature requirement 2) is a human mitochondrial protease that has a role in apoptosis and Parkinson's disease. The structure of HtrA2 with an intact catalytic triad was determined, revealing a conformational change in the active site loops, involving mainly the regulatory LD loop, which resulted in burial of the catalytic serine relative to the previously reported structure of the proteolytically inactive mutant. Mutations in the loops surrounding the active site that significantly restricted their mobility, reduced proteolytic activity both in vitro and in cells, suggesting that regulation of HtrA2 activity cannot be explained by a simple transition to an activated conformational state with enhanced active site accessibility. Manipulation of solvent viscosity highlighted an unusual bi-phasic behavior of the enzymatic activity, which together with MD calculations supports the importance of motion in the regulation of the activity of HtrA2. HtrA2 is an unusually thermostable enzyme (TM=97.3 °C), a trait often associated with structural rigidity, not dynamic motion. We suggest that this thermostability functions to provide a stable scaffold for the observed loop motions, allowing them a relatively free conformational search within a rather restricted volume.

Compulsory psychiatric treatment checklist: Instrument development and clinical application.

Instruments designed to evaluate the necessity of compulsory psychiatric treatment (CPT) are scarce to non-existent. We developed a 25-item Checklist (scoring 0 to 50) with four clusters (Legal, Danger, Historic and Cognitive), based on variables identified as relevant to compulsory treatment. The Compulsory Treatment Checklist (CTC) was filled with information on case (n=324) and control (n=251) subjects, evaluated under the Portuguese Mental Health Act (Law 36/98), in three hospitals. For internal validation, we used Confirmatory Factor Analysis (CFA), testing unidimensional and bifactor models. Multilevel logistic regression model (MLL) was used to predict the odds ratio (OR) for compulsory treatment based on the total scale score. Receiver Operating Characteristic analysis (ROC) was performed to predict compulsory treatment. CFA revealed the best fit indexes for the bifactor model, with all items loading on one General factor and the residual loading in the a priori predicted four specific factors. Reliability indexes were high for the General factor (88.4%), and low for specific factors (<5%), which demonstrate that CTC should not be performed in the subscales to access compulsory treatment. MLL reveals that for each item scored in the scale, it increases the OR by 1.26 for compulsory treatment (95%CI 1.21-1.31, p<0.001). Based on the total score, accuracy was 90%, and the best cut-off point of 23.5 detects compulsory treatment with a sensitivity of 75% and specificity of 93.6%. The CTC presents robust internal structure with a strong unidimensional characteristic, and a cut-off point for compulsory treatment of 23.5. The improved 20-item version of the CTC could represent an important instrument to improve clinical decision regarding CPT, and ultimately to improve mental health care of patients with severe psychiatric disorders.

Functional ability in younger and older elderlies after discharge from the intensive care unit. A prospective cohort. / Capacidade funcional em idosos e idosos mais velhos após alta da unidade de terapia intensiva. Coorte prospectiva.

OBJECTIVE: To compare the functional capacity of younger elderly individuals (60 to 79 years old) with that of older elderly individuals (≥ 80 years old) during the first 6 months after discharge from the intensive care unit. METHODS: A multicenter prospective cohort study was conducted, in which data on intensive care unit admission and outcomes after hospital discharge (immediate post-discharge, after 3 months and after 6 months) were collected. Muscle strength was evaluated through the protocol of the Medical Research Council and dynamometry (handgrip); the ability to perform activities of daily life and functional independence were assessed by the Barthel index and the usual level of physical activity (International Physical Activity Questionnaire); and quality of life was assessed by the 12-Item Short-Form Health Survey Version 2. RESULTS: Among the 253 patients included, 167 were younger elderly (between 61 and 79 years old), and 86 were older elderly (≥ 80 years old). During the sixth month of evaluation, the older elderlies presented a higher need for a caregiver (69.0% versus 49, 5%, p = 0.002). Functional capacity prior to intensive care unit admission and in the third month after discharge was lower in older elderlies than in younger ones (Barthel prior to the intensive care unit: 73.0 ± 30.0 versus 86.5 ± 22.6; p <0.001, Barthel in the third month: 63.5 ± 34.0 versus 71.5 ± 35.5, p = 0.03), as was the usual level of physical activity (International Physical Activity Questionnaire in the third month: active/very active 3.4% versus 18.3%, no physical activity 64.4% versus 39.7%, p < 0.001, and International Physical Activity Questionnaire in the sixth month: active/very active 5.8% versus 20.8%, no physical activity 69.2% versus 43.4%, p = 0.005). Older elderlies had lower muscle strength when assessed according to handgrip in both the dominant (14.5 ± 7.7 versus 19.9 ± 9.6, p = 0.008) and non-dominant limb (13.1 ± 6.7 versus 17.5 ± 9.1, p = 0.02). There were no differences in functional capacity loss or reported quality of life between the age groups. CONCLUSION: Although there were great functional capacity losses after discharge from the intensive care unit in both age groups, there was no difference in the magnitude of functional capacity loss between younger (60 to 79 years) and older elderly individuals (≥ 80 years old) during the first 6 months after discharge from the intensive care unit.

OBJETIVO: Comparar a capacidade funcional de indivíduos idosos (60 a 79 anos) com a dos idosos mais velhos (≥ 80 anos) nos primeiros 6 meses após a alta da unidade de terapia intensiva. MÉTODOS: Coorte prospectiva multicêntrica, na qual foram coletados dados referentes à internação na unidade de terapia intensiva e aos desfechos após a alta hospitalar (no pós-alta imediato, após 3 meses e após 6 meses). A força muscular foi avaliada por meio do protocolo do Medical Research Council e da dinamometria (preensão palmar); a capacidade de execução das Atividades de Vida Diária e independência funcional pelo índice de Barthel e pelo nível habitual de atividade física (International Physical Activity Questionnaire); e a qualidade de vida pelo 12-Item Short-Form Health Survey Versão 2. RESULTADOS: Dentre os 253 pacientes incluídos, 167 eram idosos entre 61 a 79 anos, e 86 eram idosos mais velhos. Os idosos mais velhos, no sexto mês de avaliação, apresentaram maior necessidade de cuidador (69,0% versus 49,5%; p = 0,002). A funcionalidade prévia à unidade de terapia intensiva e no terceiro mês após alta foi menor nos idosos mais velhos em comparação aos mais jovens (Barthel anterior à unidade de terapia intensiva: 73,0 ± 30,0 versus 86,5 ± 22,6; p < 0,001; Barthel no terceiro mês: 63,5 ± 34,0 versus 71,5 ± 35,5; p = 0,03), assim como o nível habitual de atividade física (International Physical Activity Questionnaire no terceiro mês: ativo/muito ativo 3,4% versus 18,3%; nenhuma atividade física 64,4% versus 39,7%; p < 0,001; e International Physical Activity Questionnaire no sexto mês: ativo/muito ativo 5,8% versus 20,8%; nenhuma atividade física 69,2% versus 43,4%; p = 0,005). Os idosos mais velhos apresentaram menor força muscular ao serem avaliados pela preensão palmar no membro dominante (14,5 ± 7,7 versus 19,9 ± 9,6; p = 0,008) e do não dominante (13,1 ± 6,7 versus 17,5 ± 9,1; p = 0,02). Não houve diferença na perda da funcionalidade e na qualidade de vida referida, entre os grupos etários. CONCLUSÃO: Mesmo com grande perda funcional após a alta da unidade de terapia intensiva em ambos os grupos etários, não houve diferença na magnitude da perda da funcionalidade de indivíduos idosos (60 a 79 anos) quando comparados aos idosos mais velhos (≥ 80 anos) nos primeiros 6 meses após a alta da unidade de terapia intensiva.

Capacidade funcional em idosos e idosos mais velhos após alta da unidade de terapia intensiva. Coorte prospectiva / Functional ability in younger and older elderlies after discharge from the intensive care unit. A prospective cohort

RESUMO Objetivo: Comparar a capacidade funcional de indivíduos idosos (60 a 79 anos) com a dos idosos mais velhos (≥ 80 anos) nos primeiros 6 meses após a alta da unidade de terapia intensiva. Métodos: Coorte prospectiva multicêntrica, na qual foram coletados dados referentes à internação na unidade de terapia intensiva e aos desfechos após a alta hospitalar (no pós-alta imediato, após 3 meses e após 6 meses). A força muscular foi avaliada por meio do protocolo do Medical Research Council e da dinamometria (preensão palmar); a capacidade de execução das Atividades de Vida Diária e independência funcional pelo índice de Barthel e pelo nível habitual de atividade física (International Physical Activity Questionnaire); e a qualidade de vida pelo 12-Item Short-Form Health Survey Versão 2. Resultados: Dentre os 253 pacientes incluídos, 167 eram idosos entre 61 a 79 anos, e 86 eram idosos mais velhos. Os idosos mais velhos, no sexto mês de avaliação, apresentaram maior necessidade de cuidador (69,0% versus 49,5%; p = 0,002). A funcionalidade prévia à unidade de terapia intensiva e no terceiro mês após alta foi menor nos idosos mais velhos em comparação aos mais jovens (Barthel anterior à unidade de terapia intensiva: 73,0 ± 30,0 versus 86,5 ± 22,6; p < 0,001; Barthel no terceiro mês: 63,5 ± 34,0 versus 71,5 ± 35,5; p = 0,03), assim como o nível habitual de atividade física (International Physical Activity Questionnaire no terceiro mês: ativo/muito ativo 3,4% versus 18,3%; nenhuma atividade física 64,4% versus 39,7%; p < 0,001; e International Physical Activity Questionnaire no sexto mês: ativo/muito ativo 5,8% versus 20,8%; nenhuma atividade física 69,2% versus 43,4%; p = 0,005). Os idosos mais velhos apresentaram menor força muscular ao serem avaliados pela preensão palmar no membro dominante (14,5 ± 7,7 versus 19,9 ± 9,6; p = 0,008) e do não dominante (13,1 ± 6,7 versus 17,5 ± 9,1; p = 0,02). Não houve diferença na perda da funcionalidade e na qualidade de vida referida, entre os grupos etários. Conclusão: Mesmo com grande perda funcional após a alta da unidade de terapia intensiva em ambos os grupos etários, não houve diferença na magnitude da perda da funcionalidade de indivíduos idosos (60 a 79 anos) quando comparados aos idosos mais velhos (≥ 80 anos) nos primeiros 6 meses após a alta da unidade de terapia intensiva.

ABSTRACT Objective: To compare the functional capacity of younger elderly individuals (60 to 79 years old) with that of older elderly individuals (≥ 80 years old) during the first 6 months after discharge from the intensive care unit. Methods: A multicenter prospective cohort study was conducted, in which data on intensive care unit admission and outcomes after hospital discharge (immediate post-discharge, after 3 months and after 6 months) were collected. Muscle strength was evaluated through the protocol of the Medical Research Council and dynamometry (handgrip); the ability to perform activities of daily life and functional independence were assessed by the Barthel index and the usual level of physical activity (International Physical Activity Questionnaire); and quality of life was assessed by the 12-Item Short-Form Health Survey Version 2. Results: Among the 253 patients included, 167 were younger elderly (between 61 and 79 years old), and 86 were older elderly (≥ 80 years old). During the sixth month of evaluation, the older elderlies presented a higher need for a caregiver (69.0% versus 49, 5%, p = 0.002). Functional capacity prior to intensive care unit admission and in the third month after discharge was lower in older elderlies than in younger ones (Barthel prior to the intensive care unit: 73.0 ± 30.0 versus 86.5 ± 22.6; p <0.001, Barthel in the third month: 63.5 ± 34.0 versus 71.5 ± 35.5, p = 0.03), as was the usual level of physical activity (International Physical Activity Questionnaire in the third month: active/very active 3.4% versus 18.3%, no physical activity 64.4% versus 39.7%, p < 0.001, and International Physical Activity Questionnaire in the sixth month: active/very active 5.8% versus 20.8%, no physical activity 69.2% versus 43.4%, p = 0.005). Older elderlies had lower muscle strength when assessed according to handgrip in both the dominant (14.5 ± 7.7 versus 19.9 ± 9.6, p = 0.008) and non-dominant limb (13.1 ± 6.7 versus 17.5 ± 9.1, p = 0.02). There were no differences in functional capacity loss or reported quality of life between the age groups. Conclusion: Although there were great functional capacity losses after discharge from the intensive care unit in both age groups, there was no difference in the magnitude of functional capacity loss between younger (60 to 79 years) and older elderly individuals (≥ 80 years old) during the first 6 months after discharge from the intensive care unit.

Clarifying the Catalytic Mechanism of Human Glutamine Synthetase: A QM/MM Study.

Glutamine synthetase (GS) is a crucial enzyme responsible for the elimination of both neurotoxic glutamate and toxic ammonium, by combining them into glutamine. Alterations on the GS activity are associated with severe liver and neurodegenerative diseases and its absence or malformation results in death. In this work, the catalytic mechanism of human GS has been investigated with high-level QM/MM calculations, showing a two-phase reaction cycle. During phase 1, GS activates the reactants (NH4+ and glutamate) with extreme efficiency, through NH4+ deprotonation by E305 and glutamate phosphorylation by ATP, in two spontaneous and barrierless reactions. At phase 2, NH3 attacks the γ-glutamyl phosphate being concomitantly deprotonated by the leaving PO43-, forming the glutamine and HPO42- products. The second phase contains the rate limiting step, with a ΔG‡ of 19.2 kcal·mol-1 associated with the nucleophilic substitution of the phosphate by NH3. The final reaction free energy is -34.5 kcal·mol-1. Both phases are exergonic, the first by -22.9 kcal·mol-1 and the second by -11.6 kcal·mol-1. Direct NH4+ attack is shown to be inefficient; the possible bases that perform the NH4+ deprotonation were systematically investigated. Negative E305 was shown to be the only one possibly responsible for NH4+ deprotonation. Altogether, these results provide a clear atomic level picture of the reaction cycle of GS, consistent with experimental and theoretical studies on GS of this and other organisms, and provide the necessary insights for the development of more specific therapeutic GS inhibitors.

A low fermentable oligo-di-mono-saccharides and polyols (FODMAP) diet is a balanced therapy for fibromyalgia with nutritional and symptomatic benefits

INTRODUCTION: Fibromyalgia is a chronic rheumatic disease producing widespread pain, associated to a major comorbidity -irritable bowel syndrome. Low FODMAPS diet (low fermentable oligo-di-mono-saccharides and polyols diet) has been effective in controlling irritable bowel syndrome symptoms. Overweight is an aggravating factor for fibromyalgia. We studied effects of low fermentable oligo-di-mono-saccharides and polyols diets on fibromyalgia symptoms and weight status. METHODS: A longitudinal study was performed on 38 fibromyalgia patients using a four-week, repeated assessment as follow: M1 = first assessments/presentation of individual low fermentable oligo-di-mono-saccharides and polyols diet; M2 = second assessments/reintroduction of FODMAPs; M3 = final assessments/nutritional counselling. The assessment instruments applied were: Fibromyalgia Survey Questionnaire (FSQ); Severity Score System (IBS-SSS); visual analogic scale (VAS). Body mass-index/composition and waist circumference (WC) were also measured. Daily macro-micronutrients and FODMAP intake were quantified at each moment of the study. RESULTS: The studied cohort was 37% overweight, 34% obese (average body mass-index 27.4 ± 4.6; excess fat mass 39.4 ± 7%). Weight, body mass-index and waist circumference decreased significantly (p < 0.01) with low fermentable oligo-di-mono-saccharides and polyols diet, but no significant effect on body composition was observed. All fibromyalgiasymptoms, including somatic pain, declined significantly post-LFD (p < 0.01); as well for severity of fibromyalgia [Fibromyalgia survey questionnaire: M1 = 21.8; M2 = 16.9; M3 = 17.0 (p < 0.01)]. The intake of essential nutrients (fiber, calcium, magnesium and vitamin D) showed no significant difference. The significant reduction in FODMAP intake (M1 = 24.4 g; M2 = 2.6g; p < 0.01) reflected the "Diet adherence" (85%). "Satisfaction with improvement of symptoms" (76%), showed correlating with "diet adherence" (r = 0.65; p < 0.01). CONCLUSIONS: Results are highly encouraging, showing low fermentable oligo-di-mono-saccharides and polyols diets as a nutritionally balanced approach, contributing to weight loss and reducing the severity of FM fibromyalgiasymptoms.

A low fermentable oligo-di-mono-saccharides and polyols (FODMAP) diet is a balanced therapy for fibromyalgia with nutritional and symptomatic benefits / Una dieta baja en oligo-, di- y monosacáridos (FODMAPs) es un tratamiento adecuado para pacientes con fibromialgia, con beneficios clínicos y nutricionales

Introduction: Fibromyalgia is a chronic rheumatic disease producing widespread pain, associated to a major comorbidity -irritable bowel syndrome. Low FODMAPS diet (low fermentable oligo-di-mono-saccharides and polyols diet) has been effective in controlling irritable bowel syndrome symptoms. Overweight is an aggravating factor for fibromyalgia. We studied effects of low fermentable oligo-di-mono-saccharides and polyols diets on fibromyalgia symptoms and weight status. Methods: A longitudinal study was performed on 38 fibromyalgia patients using a four-week, repeated assessment as follow: M1 = first assessments/presentation of individual low fermentable oligo-di-mono-saccharides and polyols diet; M2 = second assessments/reintroduction of FODMAPs; M3 = final assessments/nutritional counselling. The assessment instruments applied were: Fibromyalgia Survey Questionnaire (FSQ); Severity Score System (IBS-SSS); visual analogic scale (VAS). Body mass-index/composition and waist circumference (WC) were also measured. Daily macro-micronutrients and FODMAP intake were quantified at each moment of the study. Results: The studied cohort was 37% overweight, 34% obese (average body mass-index 27.4 ± 4.6; excess fat mass 39.4 ± 7%). Weight, body mass-index and waist circumference decreased significantly (p < 0.01) with low fermentable oligo-di-mono-saccharides and polyols diet, but no significant effect on body composition was observed. All fibromyalgia symptoms, including somatic pain, declined significantly post-LFD (p < 0.01); as well for severity of fibromyalgia [Fibromyalgia survey questionnaire: M1 = 21.8; M2 = 16.9; M3 = 17.0 (p < 0.01)]. The intake of essential nutrients (fiber, calcium, magnesium and vitamin D) showed no significant difference. The significant reduction in FODMAP intake (M1 = 24.4 g; M2 = 2.6g; p < 0.01) reflected the «Diet adherence» (85%). «Satisfaction with improvement of symptoms» (76%), showed correlating with «diet adherence» (r = 0.65; p < 0.01). Conclusions: Results are highly encouraging, showing low fermentable oligo-di-mono-saccharides and polyols diets as a nutritionally balanced approach, contributing to weight loss and reducing the severity of FM fibromyalgia symptoms (AU)

Introducción: la fibromialgia es una enfermedad reumática crónica, que tiene unas importantes comorbilidades-síndrome del intestino irritable (SII). La dieta baja en FODMAPs (low fermentable oligo-di-mono-saccharides and polyols diet) ha sido eficaz en el tratamiento del síndrome del intestino irritable. El sobrepeso es un factor agravante. Se estudiaron los efectos nutricionales del FODMAPs en la fibromialgia. Métodos: estudio longitudinal en 38 pacientes con fibromialgia en el que se utilizó una evaluación repetida, durante cuatro semanas, de lo siguiente: Moment 1 (M1) = primeras evaluaciones/presentación de FODMAPs; M2 = segundas evaluaciones/reintroducción de FODMAPs; M3 = evaluaciones finales/asesoramiento nutricional. Instrumentos de evaluación: Fibromialgia Survey Questionnaire; síndrome del intestino irritable (IBS-SSS), escala visual analógica (EVA) y parámetros antropométricos. Cuantificación en todo momento de las ingestas diarias de macro/micro nutrientes y FODMAPs. Resultados: el estudio de cohorte mostró 37% de sobrepeso y 34% obesidad; índice de masa corporal = 27,4 ± 4,6; masa grasa = 39,4 ± 7%. El peso y la circunferencia de la cintura disminuyeron significativamente con FODMAPs, pero no cambió la composición corporal. Los síntomas y la severidad de la fibromialgia (FSQ: M1 = 21,8; M2 = 16,9; M3 = 17,0) se redujeron significativamente después de FODMPAs (p < 0,01). No fueron observadas diferencias significativas en el consumo de nutrientes esenciales, especialmente la fi bra, calcio, magnesio y vitamina D. El «seguimiento de la dieta» fue del 85% con reducción significativa de la ingesta de FODMAPs (p < 0,01: M1 = 24,4 g; M2 = 2,6 g). «La satisfacción con la mejora de los síntomas» (76%) se correlacionó con el «seguimiento de la dieta» (r = 0,65; p < 0,01). Conclusiones: los resultados son muy alentadores, mostrando FODMAPs como un enfoque equilibrado nutricionalmente, que contribuyó a la pérdida de peso y redujo significativamente la severidad de la FM (AU)

Validación de la versión en portugués de la Escala de Evaluación de Síntomas Psicóticos (PSYRATS) / Validation of the Portuguese version of the Psychotic Symptom Rating Scales (PSYRATS)

La Escala de Valoración de Síntomas Psicóticos (PSYRATS) es una herramienta de evaluación clínica que se centra en la medición detallada de delirios y alucinaciones en pacientes con psicosis. El objetivo de este estudio fue examinar las propiedades psicométricas de la versión en portugués de la PSYRATS. Se evaluó una muestra de 92 pacientes ambulatorios con la PSYRATS y la Escala de Síndromes Positivo y Negativo (PANSS). Los pacientes padecían de esquizofrenia o trastornos esquizoafectivos y presentaban síntomas psicóticos persistentes. Se encontró una buena fiabilidad entre evaluadores, fiabilidad de repetibilidad, validez concurrente y consistencia interna. El análisis factorial de los ítems de la escala de alucinaciones auditivas reveló una solución de cuatro factores: características de la emoción y factor de perturbación (factor 1), un factor de características físicas (factor 2), un factor de características de control (factor 3) y un factor de atribución cognitiva (factor 4). En cuanto a los ítems de la escala de delirios, se encontró una solución de dos factores: un factor de interpretación cognitiva y perturbación (factor 1) y un factor de características emocionales (factor 2). La versión en portugués de la PSYRATS replicó parcialmente resultados publicados anteriormente en otros países

The Psychotic Symptom Rating Scales (PSYRATS) is a clinical assessment tool that focuses on the detailed measurement of delusions and hallucinations in patients with psychosis. The goal of this study was to examine the psychometric properties of the Portuguese version of the PSYRATS. A sample of 92 outpatients suffering from schizophrenia or schizoaffective disorders and presenting persistent psychotic symptoms was assessed using the PSYRATS and the Positive and Negative Syndrome Scale (PANSS). Good inter-rater reliability, test-retest reliability, concurrent validity and internal consistency were found. Factor analysis of the auditory hallucinations scale items disclosed a four-factor solution: emotion characteristics and disruption factor (factor 1), a physical characteristics factor (factor 2), a control characteristics factor (factor 3) and a cognitive attribution factor (factor 4). Regarding the delusions scale items, a two-factor solution was found: cognitive interpretation and disruption factor (factor 1) and an emotional characteristics (factor 2). The Portuguese version of the PSYRATS partially replicates previously published results in other countries

Validation of the Portuguese version of the Psychotic Symptom Rating Scales (PSYRATS).

The Psychotic Symptom Rating Scales (PSYRATS) is a clinical assessment tool that focuses on the detailed measurement of delusions and hallucinations in patients with psychosis. The goal of this study was to examine the psychometric properties of the Portuguese version of the PSYRATS. A sample of 92 outpatients suffering from schizophrenia or schizoaffective disorders and presenting persistent psychotic symptoms was assessed using the PSYRATS and the Positive and Negative Syndrome Scale (PANSS). Good inter-rater reliability, test-retest reliability, concurrent validity and internal consistency were found. Factor analysis of the auditory hallucinations scale items disclosed a four-factor solution: emotion characteristics and disruption factor (factor 1), a physical characteristics factor (factor 2), a control characteristics factor (factor 3) and a cognitive attribution factor (factor 4). Regarding the delusions scale items, a two-factor solution was found: cognitive interpretation and disruption factor (factor 1) and an emotional characteristics (factor 2). The Portuguese version of the PSYRATS partially replicates previously published results in other countries.

The Proximity between Hallucination and Delusion Dimensions: An Observational, Analytic, Cross-Sectional, Multicentre Study.

In psychiatric classifications, hallucinations (mainly auditory hallucinations) are one of the fundamental criteria for establishing a schizophrenia diagnosis or any of the related psychotic disorder's diagnoses. The conceptual proximity between delusions and hallucinations was maintained until the end of the XIX century, with several supporters during the XX century. Their limits were not yet definitely defined in terms of Descriptive Psychopathology, and much less so in terms of biochemical and anatomical models. In this article we aimed to analyse the dimensions of both hallucinations and delusions in a sample of patients with schizophrenia and schizoaffective disorder. We also intend to find the determinants of the main dimensions of hallucinations. One hundred patients with schizophrenia (80) or schizoaffective disorder (20), 64% males, mean age 39.75, from the outpatient and inpatient units of the Psychiatry Department of Hospital de Santa Maria and the Centro Hospitalar Psiquiátrico de Lisboa were assessed by means of the Psychotic Symptom Rating Scales (PSYRATS) and a structured interview. In this study we designed an empirical based model by means of bivariate Spearman's rank correlation coefficient, and multivariate statistics (linear regression and multiple multivariate linear regression), where the main dimensions of hallucinations are determined by the central dimensions of delusions.

Cholesterol Biosynthesis: A Mechanistic Overview.

Cholesterol is an essential component of cell membranes and the precursor for the synthesis of steroid hormones and bile acids. The synthesis of this molecule occurs partially in a membranous world (especially the last steps), where the enzymes, substrates, and products involved tend to be extremely hydrophobic. The importance of cholesterol has increased in the past half-century because of its association with cardiovascular diseases, which are considered one of the leading causes of death worldwide. In light of the current need for new drugs capable of controlling the levels of cholesterol in the bloodstream, it is important to understand how cholesterol is synthesized in the organism and identify the main enzymes involved in this process. Taking this into account, this review presents a detailed description of several enzymes involved in the biosynthesis of cholesterol. In this regard, the structure and catalytic mechanism of the enzymes involved in cholesterol biosynthesis, from the initial two-carbon acetyl-CoA building block, will be reviewed and their current pharmacological importance discussed. We believe that this review may contribute to a deeper level of understanding of cholesterol metabolism and that it will serve as a useful resource for future studies of the cholesterol biosynthesis pathway.