Exploring the Esterase Catalytic Activity of Minimalist Heptapeptide Amyloid Fibers.

This paper investigates the esterase activity of minimalist amyloid fibers composed of short seven-residue peptides, IHIHIHI (IH7) and IHIHIQI (IH7Q), with a particular focus on the role of the sixth residue position within the peptide sequence. Through computational simulations and analyses, we explore the molecular mechanisms underlying catalysis in these amyloid-based enzymes. Contrary to initial hypotheses, our study reveals that the twist angle of the fiber, and thus the catalytic site's environment, is not notably affected by the sixth residue. Instead, the sixth residue interacts with the p-nitrophenylacetate (pNPA) substrate, particularly through its -NO2 group, potentially enhancing catalysis. Quantum mechanics/molecular mechanics (QM/MM) simulations of the reaction mechanism suggest that the polarizing effect of glutamine enhances catalytic activity by forming a stabilizing network of hydrogen bonds with pNPA, leading to lower energy barriers and a more exergonic reaction. Our findings provide valuable insights into the intricate interplay between peptide sequence, structural arrangement, and catalytic function in amyloid-based enzymes, offering potentially valuable information for the design and optimization of biomimetic catalysts.

Cost of Hospitalizations due to Exacerbation in Patients with Non-Cystic Fibrosis Bronchiectasis.

BACKGROUND: Knowing the cost of hospitalizations for exacerbation in bronchiectasis patients is essential to perform cost-effectiveness studies of treatments that aim to reduce exacerbations in these patients. OBJECTIVES: To find out the mean cost of hospitalizations due to exacerbations in bronchiectasis patients, and to identify factors associated with higher costs. METHODS: Prospective, observational, multicenter study in adult bronchiectasis patients hospitalized due to exacerbation. All expenses from the patients' arrival at hospital to their discharge were calculated: diagnostic tests, treatments, transferals, home hospitalization, admission to convalescence centers, and hospitals' structural costs for each patient (each hospital's tariff for emergencies and 70% of the price of a bed for each day in a hospital ward). RESULTS: A total of 222 patients (52.7% men, mean age 71.8 years) admitted to 29 hospitals were included. Adding together all the expenses, the mean cost of the hospitalization was EUR 5,284.7, most of which correspond to the hospital ward (86.9%), and particularly to the hospitals' structural costs. The adjusted multivariate analysis showed that chronic bronchial infection by Pseudomonas aeruginosa, days spent in the hospital, and completing the treatment with home hospitalization were factors independently associated with a higher overall cost of the hospitalization. CONCLUSIONS: The mean cost of a hospitalization due to bronchiectasis exacerbation obtained from the individual data of each episode is higher than the cost per process calculated by the health authorities. The most determining factor of a higher cost is chronic bronchial infection due to P. aeruginosa, which leads to a longer hospital stay and the use of home hospitalization.

Physical activity and sedentary behaviour in patients admitted with COPD: Associated factors.

AIM: To establish amongst a cohort of patients admitted with Chronic Obstructive Pulmonary Disease which factors were associated with their level of Physical Activity and Sedentary Behavior prior to the admission event. METHODS: Prospective observational cohort study. Nine Spanish hospitals participated. Patients were recruited consecutively. Variables relating to the patients' clinical baseline status were recorded, including the COPD Assessment test, the HADS anxiety-depression test, comorbidities and the Yale Physical Activity Survey. Data relating to admission and up to two months after discharge were also recorded. RESULTS: 1638 COPD patients were studied, with a mean age of 72.39 (SD 10.33), 76.56 % male, FEV1 49.41 % (SD19.19), Charlson index 2. The level of PA at baseline was 30.79 points (SD 22.43). Multivariable linear regression analysis identified the following as being associated with low PA: older age, obesity, higher level of hemoglobin, lower score of Barthel index, which means disability, health related quality of life (EuroQoL-5d and CAT) and dyspnea. Variables associated with sedentary behavior were: older age, presence of obstructive apnea syndrome, higher disability, presence of depressive symptoms and dyspnea. CONCLUSIONS: In a cohort of hospitalized COPD patients, we have found several variables, some of them modifiable, associated with physical activity/inactivity and sedentary behavior.

Enfermedad de Fahr / Fahr disease

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