Interaction of microbes with mucus and mucins

Due to the recent rapid expansion in our understanding of the composition of the gut microflora and the consequences of altering that composition the question of how bacteria colonise mucus layers and interact with components of mucus, such as mucin, is now receiving widespread attention. Using a combination of mucus secreting cells, and a novel mucin microarray platform containing purified native mucins from different sources we recently demonstrated that two gastrointestinal pathogens, Helicobacter pylori and Campylobacter jejuni, colonise mucus by different mechanisms. This result emphasizes the potential for even closely related bacteria to interact with mucus in divergent ways to establish successful infection. Expanding the use of the mucin arrays described in the study to other microorganisms, both pathogenic and commensal, should lead to the discovery of biologically important motifs in bacterial-host interactions and complement the use of novel in vitro cell models, such as mucus secreting cell lines.     

Pegylated interferon for chronic hepatitis C in children affects growth and body composition: results from the pediatric study of hepatitis C (PEDS-C) trial

Weight loss and changes in growth are noted in children treated with interferon alpha (IFN-α). The aim of this study was to prospectively determine changes in weight, height, body mass index (BMI), and body composition during and after treatment of children with hepatitis C virus (HCV). Children treated with pegylated interferon alpha-2a (Peg-IFN-α2a) ± ribavirin in the Pediatric Study of Hepatitis C (PEDS-C) trial underwent anthropometric measurements, dual-energy X-ray absorptiometry scan, as well as dietary and activity assessments during and after treatment. One hundred and fourteen (55% male) children, with a mean age of 11 ± 3 years, were randomized, and 107 received treatment for at least 24 weeks. Subjects were divided into three groups according to duration of treatment: 24 (N = 14), 48 (N = 82), or 72 (N = 11) weeks. Decrements of up to 0.50 z score were observed for weight, height, and BMI while on therapy among all groups (P ≤ 0.01, compared to baseline). In the group treated for 48 weeks, 29 (33%) subjects had greater than 0.5-unit decrement in height-for-age z (HAZ) score. Though weight-for-age and BMI z scores returned to baseline after cessation of therapy, mean HAZ score was slower to rebound, still lower than baseline at 96 weeks post-therapy for the long-treatment duration group (P = 0.03) and lower than baseline in most children treated for 48 weeks. Percent body fat, fat-free mass z scores, and triceps skinfold z scores decreased with therapy. Dietary energy intake and levels of physical activity did not change during treatment. CONCLUSIONS: Peg-IFN-α2a was associated with significant changes in body weight, linear growth, BMI, and body composition in children. These effects were generally reversible with cessation of therapy, although HAZ scores had not returned to baseline after 2 years of observation in many. Longer term growth data are needed among children treated for chronic HCV.     

The difficult airway with recommendations for management – Part 1 – Difficult tracheal intubation encountered in an unconscious/induced patient

Background

Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group’s mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.

Methods

Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.

Conclusions

The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative “Plan B” technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, “cannot intubate, cannot oxygenate” situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.