HY5 inhibits lateral root initiation in Arabidopsis through negative regulation of the microtubule-stabilizing protein TPXL5.

Tight control of lateral root (LR) initiation is vital for root system architecture and function. Regulation of cortical microtubule reorganization is involved in the asymmetric radial expansion of founder cells during LR initiation in Arabidopsis (Arabidopsis thaliana). However, critical genetic evidence on the role of microtubules in LR initiation is lacking and the mechanisms underlying this regulation are poorly understood. Here, we found that the previously uncharacterized microtubule-stabilizing protein TPX2-LIKE5 (TPXL5) participates in LR initiation, which is finely regulated by the transcription factor ELONGATED HYPOCOTYL5 (HY5). In tpxl5 mutants, LR density was decreased and more LR primordia (LRPs) remained in stage I, indicating delayed LR initiation. In particular, the cell width in the peripheral domain of LR founder cells after the first asymmetric cell division was larger in tpxl5 mutants than in the wild-type. Consistently, ordered transverse cortical microtubule arrays were not well generated in tpxl5 mutants. In addition, HY5 directly targeted the promoter of TPXL5 and downregulated TPXL5 expression. The hy5 mutant exhibited higher LR density and fewer stage I LRPs, indicating accelerated LR initiation. Such phenotypes were partially suppressed by TPXL5 knockout. Taken together, our data provide genetic evidence supporting the notion that cortical microtubules are essential for LR initiation and unravel a molecular mechanism underlying HY5 regulation of TPXL5-mediated microtubule reorganization and cell remodeling during LR initiation.

Voice parameters for difficult mask ventilation evaluation: an observational study.

BACKGROUND: Mask ventilation (MV) is an essential component of airway management. Difficult mask ventilation (DMV) is a major cause for perioperative hypoxic brain injury; however, predicting DMV remains a challenge. This study aimed to determine the potential value of voice parameters as novel predictors of DMV in patients scheduled for general anesthesia. METHODS: We included 1,160 adult patients scheduled for elective surgery under general anesthesia. The clinical variables usually reported as predictors of DMV were collected before surgery. Voice sample of phonemes ([a], [o], [e], [i], [u], [ü], [ci], [qi], [chi], [le], [ke], and [en]) were recorded and their formants (f1-f4) and bandwidths (bw1-bw4) were extracted. The definition of DMV was the inability of an unassisted anesthesiologist to ensure adequate ventilation during MV under general anesthesia. Univariate and multivariate logistic regression analyses were used to explore the association between voice parameters and DMV. The predictive value of the voice parameters was evaluated by assessment of area under the curve (AUC) of receiver operating characteristic (ROC) curves of a stepwise forward model. RESULTS: The prevalence of DMV was 218/1,160 (18.8%). The AUC of the stepwise forward model (including o_f4, e_bw2, i_f3, u_pitch, u_f1, u_f4, ü_bw4, ci_f1, qi_f1, qi_f4, qi_bw4, chi_f1, chi_bw2, chi_bw4, le_pitch, le_bw3, ke_bw2, en_pitch, and en_f2, en_bw4) attained a value of 0.779. The sensitivity and specificity of the model were 75.0% and 71.0%, respectively. CONCLUSIONS: Voice parameters may be considered as alternative predictors of DMV, but additional studies are needed to confirm the initial findings.

Acoustic features as novel predictors of difficult laryngoscopy in orthognathic surgery: an observational study.

BACKGROUND: The evaluation of the difficult intubation is an important process before anaesthesia. The unanticipated difficult intubation is associated with morbidity and mortality. This study aimed to determine whether acoustic features are valuable as an alternative method to predict difficult laryngoscopy (DL) in patients scheduled to undergo orthognathic surgery. METHODS: This study included 225 adult patients who were undergoing elective orthognathic surgery under general anaesthesia with tracheal intubation. Preoperatively, clinical airway evaluation was performed, and the acoustic data were collected. Twelve phonemes {[a], [o], [e], [i], [u], [ü], [ci], [qi], [chi], [le], [ke], and [en]} were recorded, and their formants (f1-f4) and bandwidths (bw1-bw4) were extracted. Difficult laryngoscopy was defined as direct laryngoscopy with a Cormack-Lehane grade of 3 or 4. Univariate and multivariate logistic regression analyses were used to examine the associations between acoustic features and DL. RESULTS: Difficult laryngoscopy was reported in 59/225 (26.2%) patients. The area under the curve (AUC) of the backward stepwise model including en_f2 [odds ratio (OR), 0.996; 95% confidence interval (CI), 0.994-0.999; P=0.006], ci_bw4 (OR, 0.997; 95% CI, 0.993-1.000; P=0.057), qi_bw4 (OR, 0.996; 95% CI, 0.993-0.999; P=0.017), le_f3 (OR, 0.998; 95% CI, 0.996-1.000; P=0.079), o_bw4 (OR, 1.001; 95% CI, 1.000-1.003; P=0.014), chi_f4 (OR, 1.003; 95% CI, 1.000-1.005; P=0.041), a_bw4 (OR, 0.999; 95% CI, 0.998-1.000; P=0.078) attained a value of 0.761 in the training set, but a value of 0.709 in the testing set. The sensitivity and specificity of the model in the testing set are 86.7% and 63.0%, respectively. CONCLUSIONS: Acoustic features may be considered as useful predictors of DL during orthognathic surgery.