Bacterial chemoreceptors sense the extracellular signals and regulate bacterial motilities, biofilm formation, etc. The periplasmic ligand binding domains of chemoreceptors occur as different structural folds and recognize a diversity of chemical molecules. In Pseudomonas aeruginosa (PAO1), two bacterial chemoreceptors, McpN (PA2788) and PilJ (PA0411), are proposed to both contain a PilJ-like ligand-binding domain (LBD) (Pfam motif PF13675) and involved in nitrate chemotaxis and type IV pilus-mediated motility, respectively. The LBDs of McpN and PilJ consist of 135 and 263 residues, respectively, and share very low sequence identity, suggesting they might occur as different structures. Here, we found that PilJ-LBD folded into an HBM module, the same as the sensor domains of McpS-LBD and TorS-LBD, but it differed from that of McpN-LBD. We also observed a trimer in SEC and AUC and proposed a trimeric model based on the crystal structure. Based on the sequence, we classified the Pfam containing McpN-LBD and PilJ-LBD into three classes: sPilJ (single PilJ) represented by McpN-LBD with only one PilJ domain, dPilJ (dual PilJ) that contained dual PilJ domains, and hPilJ (hybrid PilJ) that comprises of a PilJ domain and another non-PilJ domain. Our work indicates a significant structural difference between the ligand binding domains of PilJ and McpN and will help our further study on both kinds of chemoreceptors.

BACKGROUND: Transoral robotic surgery (TORS) is a reliable, minimally invasive approach for treating recurrent nasopharyngeal carcinoma (rNPC). However, tumours involving the internal carotid artery (ICA) are considered to be unsuitable for TORS. This paper presents the first case of transoral robotic resection of advanced rNPC involving the ICA.
METHODS: This case is a 55 year-old male patient who received radiotherapy 27 years ago. This patient underwent a standard TORS resection 2 weeks after ipsilateral ICA embolization.
RESULTS: Postoperative Magnetic resonance imaging and biopsy results indicated total resection. During the 2 month follow-up, no severe complications were found, and the primary site was tumour-free.
CONCLUSIONS: This study preliminarily presents the feasibility and efficiency of advanced rNPC resection with TORS. TORS can potentially provide better quality of life for patients as a less invasive approach than current endoscopic surgery. Even so, the surgical approach should be selected strictly according to the tumour\'s location.

UNASSIGNED: To compare the efficacy of trans-oral robotic surgery (TORS) with that of coblation assisted tongue base reduction surgery in patients with obstructive sleep apnea syndrome (OSAS).
UNASSIGNED: The medical charts were retrospectively reviewed for all OSAS patients admitted to one institution for surgical intervention between 2012 and 2017. We analyzed 33 cases; 16 patients received TORS and 17 received coblation surgery for tongue base reduction. Both groups received concomitant uvulopalatoplasty. Surgical outcomes were evaluated by comparing the initial polysomnography (PSG) parameters with the follow-up PSG data (at least 3 months after the surgery). Epworth sleepiness scale (ESS) and complications were also compared between the 2 groups.
UNASSIGNED: The success rate (≥50% reduction of pre-operative AHI and post-operative AHI <20) in the TORS group and coblation group were 50% and 58%, respectively, and there was no significant difference (p = .611). The AHI (mean ± SD) reduction in the TORS and coblation groups were 24.9 ± 26.5 events/h and 19.4 ± 24.8 events/h, respectively; the between-group difference was not significant (p = .631). ESS improvement did not differ significantly between the TORS and coblation groups (3.8 ± 6.6 and 3.1 ± 9.2, respectively, p = .873). The rates of minor complication were higher in the TORS group (50%) than that of the coblation group (35.3%) without statistical significance (p = .393).
UNASSIGNED: TORS achieved comparable surgical outcomes compared to coblation assisted tongue base reduction surgery in OSAS patients. Multilevel surgery using either TORS or coblation tongue base reduction combined with uvulopalatoplasty is an effective approach for the management of OSAS.

Transoral robotic surgery (TORS) allows for access to oropharyngeal regions in an effective and minimally invasive manner. However, safe TORS access to deep pharyngeal (such as hypopharynx) sites remains a great challenge for current surgical robotic systems. In this work, we introduce a novel continuum robot with an optimized flexible parallel mechanism, to meet stringent requirements imposed by TORS on size, workspace, flexibility, and compliance. The system is comprised of two parts, a guidance part and an execution part, and achieves 11 controllable degrees of freedom. The execution part of the robot, based on the optimized flexible parallel mechanism, is able to reach deep sites in the oropharynx and larynx with the assistance of the continuum guidance part. In addition to the mechanical design, extensive analysis and experiments were carried out. Kinematic models were derived and the reachable workspace of the robot was verified to cover the entire target surgical area. Experimental results indicate that the robot achieves significantly enhanced compliance. Additionally, the designed robot can withstand a load of 1.5 N within the allowable range of the deflection. The positioning errors caused by the interference between different mechanisms can be effectively eliminated using the proposed compensation method. The maximum displacement error of this system under various conditions is less than 2 mm and the maximum bending error is less than 7.5°, which are satisfied for TORS. Cadaver trials were conducted to further demonstrate the feasibility. The reduced setup time and the reduced time to access the target site indicate that the developed surgical robotic system can achieve better operative efficiency in TORS when compared with current systems.

This study demonstrates variations in the vascular anatomy of the parapharyngeal space (PPS) as seen from the transoral approach compared with the transcervical approach. The PPS was dissected in injected cadaveric specimens. Anatomical measurements, including those of branches of the external and internal carotid arteries (ECA and ICA) and the styloglossus and stylopharyngeus muscles, were recorded and analyzed. In 67% (8/12) of cases, the ascending palatine artery (APA) originated from the facial artery and crossed the styloglossus muscle. The diameter of the APA at its origin was 1.4 ± 0.3 mm. In 75% (9/12) of cases, the ascending pharyngeal artery (aPA) arose from the medial surface of the ECA near its origin. In 58% (7/12) of cases, the aPA ascended vertically between the ICA and the lateral pharynx to the skull base, along the longus capitus muscle. The aPA crossed the styloglossus muscle 12.6 ± 3.9 mm from the insertion into the tongue. In 92% (11/12) of cases, the ECA and ICA were separated by the styloid diaphragm and pharyngeal venous plexus. In 8% (1/12), the ECA bulged into the parapharyngeal fat between the styloglossus and stylopharyngeus muscles adjacent to the pharyngeal constrictors. Knowledge of the precise anatomy of the PPS is important for transoral robotic surgery (TORS). Control of the vessels that supply and traverse the PPS can help the TORS surgeon avoid those critical structures and reduce surgical morbidity and potential hemorrhage.