A mathematical model of competition between fiber and mucin degraders in the gut provides a possible explanation for mucus thinning.

The human gut microbiota relies on complex carbohydrates (glycans) for energy and growth, primarily dietary fiber and host-derived mucins. We introduce a mathematical model of a glycan generalist and a mucin specialist in a two-compartment chemostat model of the human colon. Our objective is to characterize the influence of dietary fiber and mucin supply on the abundance of mucin-degrading species within the gut ecosystem. Current mathematical gut reactor models that include the enzymatic degradation of glycans do not differentiate between glycan types and their degraders. The model we present distinguishes between a generalist that can degrade both dietary fiber and mucin, and a specialist species that can only degrade mucin. The integrity of the colonic mucus barrier is essential for overall human health and well-being, with the mucin specialist Akkermanisa muciniphila being associated with a healthy mucus layer. Competition, particularly between the specialist and generalists like Bacteroides thetaiotaomicron, may lead to mucus layer erosion, especially during periods of dietary fiber deprivation. Our model treats the colon as a gut reactor system, dividing it into two compartments that represent the lumen and the mucus of the gut, resulting in a complex system of ordinary differential equations with a large and uncertain parameter space. To understand the influence of model parameters on long-term behavior, we employ a random forest classifier, a supervised machine learning method. Additionally, a variance-based sensitivity analysis is utilized to determine the sensitivity of steady-state values to changes in model parameter inputs. By constructing this model, we can investigate the underlying mechanisms that control gut microbiota composition and function, free from confounding factors.

Intensive care management of a rare case of pyrexia of unknown origin (Kikuchi-Fujimoto disease).

Kikuchi-Fujimoto disease is a rare, benign cause of necrotising lymphadenitis often presenting with fever. We describe a case of a 17-year-old boy with non-verbal autism presenting to our intensive care unit with prolonged fever of unknown cause. This case highlights the role of the intensive care unit in cases of diagnostic dilemma. The critical care community should be aware of Kikuchi-Fujimoto disease as although it is usually benign, it can rarely lead to acute airway compromise.

Improving haemodialysis fistula maturation following early ultrasound vascular mapping: 'The Venous Preservation Scan'.

AIM: Formation of autogenous arteriovenous fistula (AVF) in patients with chronic kidney disease (CKD) is complicated by a high primary failure rate. We hypothesized that early (months to years before AVF creation) Venous Preservation Scan (VPS) followed by vasculature preservation is effective in protecting the patient's best 'for fistula' vasculature. This study was performed to evaluate the impact of VPS on AVF outcomes. METHODS: The case records of 123 patients who underwent ultrasound mapping for AVF creation in a district hospital were reviewed. Ninety-seven were VPS and 26 were Routine Pre-Operative Planning Scan (RPOPS) performed immediately prior to surgery. Outcomes of 21 patients who went onto AVF creation in the VPS group were compared to 23 patients in the RPOPS group. RESULTS: Success and complication rates for AVF placement in patients who underwent VPS versus RPOPS were 100% versus 91.3% (P = 0.27) and 0 versus 8.7% (P = 0.23). A greater proportion of AVF created following RPOPS required intervention before maturation (47.6% vs 19%, P = 0.05). The median primary patency of AVF created following VPS versus RPOPS was 492 (IQR 222, 1219) versus 169 (IQR 116, 414) days (P = 0.02). The cumulative patency did not differ between the two groups (median = 807 (IQR 499, 1308) versus 1059 (IQR 331, 1263) days, P = 0.26). CONCLUSIONS: This small study suggests that VPS may favourably influence the survival of primary AVF and reduce the need for assisted interventions. However, confirmation with larger randomized controlled trial is warranted.