Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Argon plasma coagulation in the management of uncovered tracheal stent fracture

Endotracheal and endobronchial stenting, particularly with uncovered stents, can be complicated by stent fracture, granulation tissue formation, direct airway injury, and airway obstruction. While stent removal is possible, it can result in significant complications and long-term benefit is not guaranteed. Argon plasma coagulation can be employed to trim fractured stent fragments and remove granulation tissue simultaneously. In this manuscript, we report a case and describe our experience with using this technique

The difficult intraoperative nasogastric tube intubation: A Review of the Literature and a Novel Approach

Nasogastric tube intubation of a patient under general anesthesia with an endotracheal tube in place can pose a challenge to the most experienced anesthesiologist. Physiologic and pathologic variations in a patient’s functional anatomy can present further difficulty. While numerous techniques to the difficult nasogastric tube intubation have been described, there is no consensus for a standard approach. Therefore, selecting the most appropriate approach requires a working knowledge of the techniques available, mindful consideration of individual patient and clinical factors, and the operator’s experience and preference. This article reviews the relevant literature regarding various approaches to the difficult nasogastric tube intubation with descriptions of techniques and results from comparative studies if available. Additionally, we present a novel approach using a retrograde technique for the difficult intraoperative nasogastric tube intubation

The difficult intraoperative nasogastric tube intubation: A Review of the Literature and a Novel Approach

Nasogastric tube intubation of a patient under general anesthesia with an endotracheal tube in place can pose a challenge to the most experienced anesthesiologist. Physiologic and pathologic variations in a patient’s functional anatomy can present further difficulty. While numerous techniques to the difficult nasogastric tube intubation have been described, there is no consensus for a standard approach. Therefore, selecting the most appropriate approach requires a working knowledge of the techniques available, mindful consideration of individual patient and clinical factors, and the operator’s experience and preference. This article reviews the relevant literature regarding various approaches to the difficult nasogastric tube intubation with descriptions of techniques and results from comparative studies if available. Additionally, we present a novel approach using a retrograde technique for the difficult intraoperative nasogastric tube intubation

The difficult intraoperative nasogastric tube intubation: A review of the literature and a novel approach

Nasogastric tube intubation of a patient under general anesthesia with an endotracheal tube in place can pose a challenge to the most experienced anesthesiologist. Physiologic and pathologic variations in a patient’s functional anatomy can present further difficulty. While numerous techniques to the difficult nasogastric tube intubation have been described, there is no consensus for a standard approach. Therefore, selecting the most appropriate approach requires a working knowledge of the techniques available, mindful consideration of individual patient and clinical factors, and the operator’s experience and preference. This article reviews the relevant literature regarding various approaches to the difficult nasogastric tube intubation with descriptions of techniques and results from comparative studies if available. Additionally, we present a novel approach using a retrograde technique for the difficult intraoperative nasogastric tube intubation

Targeting G-quadruplex for rescuing impaired chondrogenesis in WRN-deficient stem cells

Abstract Background Pathogenic mutations in WRN are a cause of premature aging disease Werner syndrome (WS). Besides accelerated aging phenotypes and cancer predisposition, patients with WS also display underdevelopment in the skeletal system, characterized by short stature, light body weight and unusually thin extremities. The reasons for these developmental defects are not completely understood and the underlying molecular mechanism remains to be elucidated. Results In this study, WRN was found to modulate transcription of short stature homeobox gene SHOX. Loss of WRN resulted in insufficient expression of SHOX, the gene dose of which is critical for driving chondrocyte differentiation. WRN could bind the G-quadruplex (G4) structures in the SHOX promoter and stimulate transcription. Aberrant formation of G4 structures in WRN-deficient cells impeded normal transcription of SHOX, thus resulting in impaired chondrogenesis. Chondrogenesis could be rescued by overexpression of WRN helicase or SHOX, suggesting that SHOX is a downstream target of WRN. Gene editing of the G4 structures in the SHOX promoter could increase SHOX expression, therefore rescuing the impaired chondrogenesis in WRN-deficient cells. Conclusions Our data suggest that dysgenesis of the developing bone in WS might be caused by SHOX insufficiency. Aberrant formation of G4 structures in SHOX promoter suppresses SHOX expression and impairs chondrogenesis. Targeted mutagenesis in the G4 structures enhances SHOX expression and thus providing an opportunity to rescue the chondrogenic defect