Validity and reliability of the Group for Learning Useful and Performant Swallowing (GLUPS) tool

INTRODUCTION

To validate the Group for Learning Useful and Performant Swallowing (GLUPS), a clinical tool dedicated to videofluoroscopy swallowing study (VFSS).

METHODS

Forty-five individuals were recruited from January 2022 to March 2023 from the Department of Otolaryngology Head and Neck Surgery of University Hospital Saint-Pierre (Brussels, Belgium). Subjects underwent VFSS, which was rated with GLUPS tool by two blinded otolaryngologists and one speech-therapist. VFSS were rated twice with GLUPS within a 7-day period to assess test-retest reliability.

RESULTS

Twenty-four patients and twenty-one controls completed the evaluations. The internal consistency (α = 0.745) and the test-retest reliability (rs = 0.941; p = 0.001) were adequate. GLUPS reported a high external validity regarding the significant correlation with the Penetration-Aspiration Scale (rs = 0.551; p = 0.001). Internal validity was adequate, because GLUPS score was significant higher in patients compared to controls (6.21 ± 4.42 versus 2.09 ± 2.00; p = 0.001). Interrater reliability did not report significant differences in the GLUPS sub- and total score among the independent judges. The mean GLUPS score of individuals without any evidence of VFSS abnormalities was 2.09/23 (95% CI  1.23-2.95), which supported that a GLUPS score ≥ 3.0 is suggestive of pathological VFSS.

CONCLUSIONS

GLUPS is a clinical instrument documenting the abnormal findings of oral and pharyngeal phases at the VFSS. GLUPS demonstrated high reliability and excellent criterion-based validity. GLUPS may be used in clinical practice for the swallowing evaluation at the VFSS.

Mechanism of NAD(P)H:quinone reductase: Ab initio studies of reduced flavin

NAD(P)H:quinone oxidoreductase type 1 (QR1, NQO1, formerly DT-diaphorase; EC 1.6.99.2) is an FAD-containing enzyme that catalyzes the nicotinamide nucleotide-dependent reduction of quinones, quinoneimines, azo dyes, and nitro groups. Animal cells are protected by QR1 from the toxic and neoplastic effects of quinones and other electrophiles. Alternatively, in tumor cells QR can activate a number of cancer chemotherapeutic agents such as mitomycins and aziridylbenzoquinones. Thus, the same enzyme that protects the organism from the deleterious effects of quinones can activate cytotoxic chemotherapeutic prodrugs and cause cancer cell death. The catalytic mechanism of QR includes an important initial step in which FAD is reduced by NAD(P)H. The unfavorable charge separation that results must be stabilized by the protein. The details of this charge stabilization step are inaccessible to easy experimental verification but can be studied by quantum chemistry methods. Here we report ab initio quantum mechanical calculations in and around the active site of the enzyme that provide information about the fine details of the contribution of the protein to the stabilization of the reduced flavin. The results show that (1) protein interactions provide approximately 2 kcal/mol to stabilize the planar conformation of the reduced flavin isoalloxazine ring observed in the X-ray structure; (2) the charge separation present in the reduced planar form of the flavin is stabilized by interactions with groups of the protein; (3) even after stabilization, the reduction potential of the cofactor remains more negative than that of the free flavin, making it a better reductant for a larger variety of quinones; and (4) the more negative reduction potential may also result in faster kinetics for the quinone reduction step.

Theory of malignant cell transformation by superoxide fate coupled with cytoskeletal electron-transport and electron-transfer

Signaling and tumor promoting functions have been experimentally assigned to the cytoskeleton, many of them linked to oxygen free radicals like superoxide. Superoxide and other reactive oxygen species (ROS) have been associated for many years with oncogenesis, and they are emerging as important signaling molecules connected to the classical signaling pathways, the cytoskeleton, the cell cycle control, and tumor initiation and promotion. Complex and multifunctional relationships between these entities are being discovered and attributed to specific protein-protein interactions. Theoretical analysis and experimental data indicate that small electronic currents may be carried by semiconduction electron transport along biopolymers. Therefore, it is proposed in this paper that the tumor-promoting effects mentioned above might be under control or modulation of these tiny electronic currents originated in relation to ROS and transported through the cytoskeletal actin microfilament network.

Is electron-transfer from glutamate receptors or other plasma membrane ionic channels involved in oxidative stress and neurodegenerative diseases?

There is theoretical evidence that biopolymers such as proteins can have semiconductor properties, with electrons (and holes) that can move inside the macromolecule. Double layers of charge can thus be formed at the plasma membrane protein interface with the electrolytes. Electron-transfer can occur at such interfaces too, and electrons can participate in charge transport processes across the biopolymer from one side of the plasma membrane to the other. These phenomena are studied here in the pathological case when the average equilibrium in the electron-transfer process at the cytoplasmic interface suffers a continued offset that leads to free-radical formation inside the cell. This would help in the long term to increase oxidative stress inside the cell, and would thus contribute to the appearance of neurodegenerative diseases.

Short note: are electron-transport and electron-transfer involved in intracellular signaling?

In this paper, the possibility of electron-transfer and subsequent electron transport across membrane proteins (ion channels) is studied with respect to the ion channel function. The electronic properties of the ionic channel protein interface with the electrolytes, and the properties of the same ion channel protein as a solid-state biopolymer are used as the physical basis to explain these elementary charge transport phenomena. It is proposed that, by means of the occurrence of those two processes, there can be electrons participating in the activation of the G-proteins and subsequent intracellular signaling. As another example, the same analysis is used to propose the involvement of electrons in the neuromodulation of the ionic channels.