SARS-CoV-2 and Dysphagia: A Retrospective Analysis of COVID-19 Patients with Swallowing Disorders.

BACKGROUND: COVID-19 can lead to impairment of neural networks involved in swallowing, since the act of swallowing is coordinated and performed by a diffuse brain network involving peripheral nerves and muscles. Dysphagia has been identified as a risk and predictive factor for the severest form of SARS-CoV-2 infection. OBJECTIVES: To investigate the association between swallowing disorders and COVID-19 in patients hospitalized for COVID-19. METHODS: We collected demographic data, medical information specific to dysphagia and data on medical treatments of patients with COVID-19. RESULTS: A total of 43 hospitalized COVID-19 patients were enrolled in the study. Twenty (46%) were evaluated positive for dysphagia and 23 (54%) were evaluated negative. Neurocognitive disorders and diabetes were mostly associated with patients who resulted positive for dysphagia. Respiratory impairment caused by COVID-19 seems to be a cause of dysphagia, since all patients who needed oxygen-therapy developed symptoms of dysphagia, unlike patients who did not. In the dysphagic group, alteration of the swallowing trigger resulted in the severest form of dysphagia. An association was found between the severest form of COVID-19 and dysphagia. This group consisted predominantly of males with longer hospitalization. CONCLUSIONS: Identification of COVID-19 patients at risk for dysphagia is crucial for better patient management.

Optical tweezers for synchrotron radiation probing of trapped biological and soft matter objects in aqueous environments.

Investigations of single fragile objects manipulated by optical forces with high brilliance X-ray beams may initiate the development of new research fields such as protein crystallography in an aqueous environment. We have developed a dedicated optical tweezers setup with a compact, portable, and versatile geometry for the customary manipulation of objects for synchrotron radiation applications. Objects of a few micrometers up to a few tens of micrometers size can be trapped for extended periods of time. The selection and positioning of single objects out of a batch of many can be performed semi-automatically by software routines. The performance of the setup has been tested by wide-angle and small-angle X-ray scattering experiments on single optically trapped starch granules, using a synchrotron radiation microbeam. We demonstrate here for the first time the feasibility of microdiffraction on optically trapped protein crystals. Starch granules and insulin crystals were repeatedly raster-scanned at about 50 ms exposure/raster-point up to the complete loss of the structural order. Radiation damage in starch granules results in the appearance of low-angle scattering due to the breakdown of the polysaccharide matrix. For insulin crystals, order along the densely packed [110] direction is preferentially maintained until complete loss of long-range order.

Very Low-Calorie Ketogenic Diet: A Safe and Effective Tool for Weight Loss in Patients With Obesity and Mild Kidney Failure.

Very low-calorie ketogenic diets (VLCKD) are an effective and increasingly used tool for weight loss. Traditionally considered high protein, ketogenic diets are often looked at with concern by clinicians due to the potential harm they pose to kidney function. We herein evaluated the efficacy and safety of a VLCKD in patients with obesity and mild kidney failure. A prospective observational real-life study was conducted on ninety-two patients following a VLCKD for approximately 3 months. Thirty-eight had mild kidney failure and fifty-four had no renal condition and were therefore designated as control. Anthropometric parameters, bioelectrical impedance and biochemistry data were collected before and at the end of the dietary intervention. The average weight loss was nearly 20% of initial weight, with a significant reduction in fat mass. We report an improvement of metabolic parameters and no clinically relevant variation regarding liver and kidney function. Upon stratification based on kidney function, no differences in the efficacy and safety outcomes were found. Interestingly, 27.7% of patients with mild renal failure reported normalization of glomerular filtrate after dietary intervention. We conclude that, when conducted under the supervision of healthcare professionals, a VLCKD is an effective and safe treatment for weight loss in patients with obesity, including those affected by mild kidney failure.

Glutamic acid-65 is an essential residue for catalysis in Proteus mirabilis glutathione S-transferase B1-1.

The functional role of three conserved amino acid residues in Proteus mirabilis glutathione S-transferase B1-1 (PmGST B1-1) has been investigated by site-directed mutagenesis. Crystallographic analyses indicated that Glu(65), Ser(103) and Glu(104) are in hydrogen-bonding distance of the N-terminal amino group of the gamma-glutamyl moiety of the co-substrate, GSH. Glu(65) was mutated to either aspartic acid or leucine, and Ser(103) and Glu(104) were both mutated to alanine. Glu(65) mutants (Glu(65)-->Asp and Glu(65)-->Leu) lost all enzyme activity, and a drastic decrease in catalytic efficiency was observed for Ser(103)-->Ala and Glu(104)-->Ala mutants toward both 1-chloro-2,4-dinitrobenzene and GSH. On the other hand, all mutants displayed similar intrinsic fluorescence, CD spectra and thermal stability, indicating that the mutations did not affect the structural integrity of the enzyme. Taken together, these results indicate that Ser(103) and Glu(104) are significantly involved in the interaction with GSH at the active site of PmGST B1-1, whereas Glu(65) is crucial for catalysis.