Phosphorylcholine Allows for Evasion of Bactericidal Antibody by Haemophilus influenzae

The human pathogen Haemophilus influenzae has the ability to quickly adapt to different host environments through phase variation of multiple structures on its lipooligosaccharide (LPS), including phosphorylcholine (ChoP). During colonization with H. influenzae, there is a selection for ChoP+ phase variants. In a murine model of nasopharyngeal colonization, this selection is lost in the absence of adaptive immunity. Based on previous data highlighting the importance of natural antibody in limiting H. influenzae colonization, the effect of ChoP expression on antibody binding and its bactericidal activity was investigated. Flow cytometric analysis revealed that ChoP+ phase variants had decreased binding of antibody to LPS epitopes compared to ChoP− phase variants. This difference in antibody binding correlated with increased survival of ChoP+ phase variants in the presence of antibody-dependent, complement-mediated killing. ChoP+ phase variants were also more resistant to trypsin digestion, suggesting a general effect on the physical properties of the outer membrane. Moreover, ChoP-mediated protection against antibody binding correlated with increased resilience of outer membrane integrity. Collectively, these data suggest that ChoP expression provides a selective advantage during colonization through ChoP-mediated effects on the accessibility of bactericidal antibody to the cell surface

Restoration of function in the paralyzed laryngeal muscles by functional electrical stimulation in cats

Elsevier, Akihiro, Katada ; Satoshi, Nonaka ; Isamu, Kunibe ; Masanobu, Imada ; Tatsuya, Hayashi ; Yasuaki, Harabuchi, International Coｎgress Series, 1240, 2003, 839-842. authorFunctional electrical stimulation (FES) has been debated as an innovative treatment in the management of patients with laryngeal paralysis. In this study, we examined whether FES to the paralyzed laryngeal adductor muscles improves the voice sounds impaired by unilateral laryngeal paralysis. We confirmed that the FES to the paralyzed thyroarytenoid muscle (TA) induced the adduction of vocal fold in decerebrate cats. Electrical stimulation delivered to periaqueductal grey (PAG) induced vocalization in the cats with unilateral laryngeal paralysis. We estimated the changes in duration of voice sounds, subglottic pressure, and quality of voice during vocalization with or without FES to the paralyzed TA muscle. The duration of voice sounds was prolonged by delivering the FES to paralyzed laryngeal adductor TA muscle. The subglottic pressure increased during vocalization with FES. The intensity of voice sounds increased, and the quality of voice sounds improved with FES. These results suggested that the FES to paralyzed adductor TA muscle could be expected to improve the quality of voice sounds in the animals with unilateral laryngeal paralysis. This study indicates the possibility that FES to the paralyzed laryngeal adductor muscles is accepted as a new therapy for patients with unilateral laryngeal paralysis

Functional electrical stimulation of laryngeal adductor muscle restores mobility of vocal fold and improves voice sounds in cats with unilateral laryngeal paralysis.

Elsevier, Katada, Akihiro ; Nonaka, Satoshi ; Adachi, Masaaki ; Kunibe, Isamu ; Arakawa, Takuya ; Imada, Masanobu ; Hayashi, Tatsuya ; Zealear, David L. ; Harabuchi, Yasuaki, Neuroscience Research, 50(2), 2004, 153-159. authorFunctional electrical stimulation (FES) has been proposed as a potential treatment for restoring motor functions of denervated motor systems. We investigated whether FES of paralyzed laryngeal adductor muscles could restore adduction to the vocal folds. In addition, we studied the effect of stimulated vocal fold adduction on the intensity and overall quality of voice production. We recorded movement of the vocal fold, electromyographic activity of muscles recruited for vocalization, and sound production in unanesthetized decerebrate cats during FES of the paralyzed thyroarytenoid (TA) muscle. FES of the paralyzed TA muscle induced adduction of the vocal fold. Appropriate stimulus parameters for induction was 1.5–3.0 mA intensity pulses delivered at a frequency of 30–50 pulses per second (pps). FES of the paralyzed TA muscle prolonged phonation time and increased intensity of voice sounds during vocalization induced by electrical stimulation (0.2 ms, 20–50 μA, 50 pps) of the periaqueductal gray (PAG). The quality of voice sounds evaluated by sound spectrography was shown to improve during vocalization with FES. We conclude that FES of the paralyzed laryngeal adductor muscle was effective in restoring adduction of the vocal fold and improving voice sounds impaired by unilateral laryngeal paralysis

Anharmonic vibrational computations with a quartic force field for curvilinear coordinates

The direct vibrational self-consistent field (VSCF) method, which combines anharmonic vibrational theory with electronic structure calculations, is a sophisticated theoretical approach to calculate the vibrational spectra of molecules from first principles. Combining the VSCF approach with the quartic force field (QFF) is a good alternative to direct VSCF, with a lower computational cost. QFF is a 4th-order Taylor expansion of the potential energy surface near an equilibrium geometry. In this study, a new strategy is proposed to derive the QFF in terms of normal coordinates; the QFF coefficients are determined through numerical differentiations of the energy by representing the normal coordinates in internal rather than Cartesian coordinates. The VSCF/QFF-internal method was implemented in the General Atomic and Molecular Electronic Structure System electronic structure program and applied to the evaluations of the fundamental vibrational frequencies of HNO2, HNO3, H2O dimer, and H2O trimer, using Møller-Plesset second order perturbation theory and the aug-cc-pVDZ and aug-cc-pVTZ basis sets. The results are much improved, especially for the intermolecular vibrational modes, compared with the Cartesian coordinate representation of the normal coordinates in the VSCF/QFF approach.This article is published as Harabuchi, Yu, Ryosuke Tani, Nuwan De Silva, Bosiljka Njegic, Mark S. Gordon, and Tetsuya Taketsugu. "Anharmonic vibrational computations with a quartic force field for curvilinear coordinates." The Journal of Chemical Physics 151, no. 6 (2019): 064104. DOI: 10.1063/1.5096167. Copyright 2019 Author(s). Posted with permission