Investigating the Impact of Polymer Length, Attachment Site, and Charge on Enzymatic Activity and Stability of Cellulase.

The thermophilic cellulase Cel5a from Fervidobacterium nodosum (FnCel5a) was conjugated with neutral, cationic, and anionic polymers of increasing molecular weights. The enzymatic activity toward an anionic soluble cellulose derivative, thermal stability, and functional chemical stability of these bioconjugates were investigated. The results suggest that increasing polymer chain length for polymers compatible with the substrate enhances the positive impact of polymer conjugation on enzymatic activity. Activity enhancements of nearly 100% were observed for bioconjugates with N,N-dimethyl acrylamide (DMAm) and N,N-dimethyl acrylamide-2-(N,N-dimethylamino)ethyl methacrylate (DMAm/DMAEMA) due to proposed polymer-substrate compatibility enabled by potential noncovalent interactions. Double conjugation of two functionally distinct polymers to wild-type and mutated FnCel5a using two conjugation methods was achieved. These doubly conjugated bioconjugates exhibited similar thermal stability to the unmodified wild-type enzyme, although enzymatic activity initially gained from conjugation was lost, suggesting that chain length may be a better tool for bioconjugate activity modulation than double conjugation.

Does Hirschsprung-Associated Enterocolitis Differ in Children With and Without Down Syndrome?

BACKGROUND: Children with Hirschsprung disease (HD) and Down syndrome (DS) are reported to experience a higher incidence of Hirschsprung-associated enterocolitis (HAEC) than those without DS, although whether their individual episodes are more severe is unknown. METHODS: A single-institution retrospective cohort study was performed on all patients with HD admitted with HAEC between 2009 and 2017. Patients were divided into two groups based on an associated diagnosis of DS, and demographics, clinical characteristics at presentation, and clinical outcomes were compared. RESULTS: Of 86 admissions for HAEC over the study period, 12 (14%) were for patients with DS. Patients admitted with and without DS were similar in terms of age (3.0 versus 2.6 y, P = 0.72), male gender (58% versus 77%, P = 0.17), and proportion with disease proximal to the left colon (9% versus 12%, P = 0.70). Patients admitted with DS were more likely to be tachycardic (75% versus 19%, P ≤ 0.001) and hypotensive (33% versus 7%, P = 0.01) at presentation and presented for treatment after a longer duration of symptoms than those without DS (84 versus 24 h, P = 0.001). Patients admitted with DS were more likely to require intensive care unit admission (58% versus 12%, P = 0.006) and received a longer course of antibiotics (13 d versus 7 d, P = 0.02). The length of stay was similar (6 versus 4 d, P = 0.34). CONCLUSIONS: The results of our study suggest that patients with DS experience more severe episodes of HAEC. Ongoing study is needed to identify preventive strategies to decrease the morbidity of HAEC in children with HD and DS.

Antegrade continence enemas in children with functional constipation and dyssynergic defecation: Go or no go?

OBJECTIVE: To assess outcomes of children with functional constipation after antegrade continence enemas (ACEs) and determine if pre operative anorectal manometry (AMAN) findings, including dyssynergic defecation, are associated with outcomes. METHODS: A retrospective review of pediatric patients with functional constipation who received a Malone appendicostomy or cecostomy after failed medical management was conducted. Patients were included if they had AMAN data prior to their operation. Patients that underwent colonic resection were excluded. Demographics, clinical characteristics, manometry results, and post ACE outcomes were obtained. Descriptive statistics were performed. RESULTS: Thirty-nine patients were identified with median age at ACE of 8.9 years (IQR: 7.2-12.6) and median follow-up of 2.5 years (IQR: 1.8-3.2 years). Twenty patients (51%) were female and most (35, 92%) were White. All patients had severe constipation prior to ACE and 59% had fecal incontinence. Thirty-four patients (87%) received a Malone and 5 (13%) received a cecostomy. Post ACE, 35 (90%) were clean with daily flushes and 6 (15%) eventually successfully transitioned to laxatives only. Awake AMAN and balloon expulsion test were performed in 15 patients, with 14 (93%) displaying evidence of dyssynergic defecation. Twelve of 14 of patients (86%) with dyssynergia were clean with ACE at follow-up. because of the majority of patients being clean post ACE, there was limited power to detect predictors of poor outcomes. CONCLUSIONS: ACEs are successful treatment options for patients with severe constipation and fecal incontinence, including those with dyssynergic defecation. Larger studies are needed to identify factors predictive of poor outcomes. LEVEL OF EVIDENCE: III.

Pilot study of an adult bowel management program for fecal incontinence.

OBJECTIVE: Bowel management programs are efficacious in pediatric patients with fecal incontinence or intractable constipation unresponsive to standard treatment. No studies have been done examining outcomes in adults. The objective of this study was to assess continence and quality of life outcomes in adults who have underwent bowel management program. METHODS: A retrospective review of patients 16 or older at the time they underwent a bowel management program for fecal incontinence or constipation was performed. Data collected included intake and follow-up stool and urinary continence, patient-reported outcomes measures (Cleveland Clinic Constipation Score, Baylor Continence Scale, Vancouver Symptom Score for Dysfunctional Elimination), and an age-adjusted health-related quality of life measure. RESULTS: The cohort included 38 patients with a median age of 19 years (range: 16-55) when they underwent our program. 50% of patients were female and the majority (33, 87%) were White. The most common diagnosis was anorectal malformation (16, 42%) followed by functional constipation (10, 27%). Stool continence rates improved after undergoing the program (52.7% prior to 87.6% at follow-up, p<0.01). There was significant improvement in the Baylor Continence Scale, Cleveland Clinic Constipation Score, and PedsQL (p<0.05). CONCLUSIONS: Adult patients who underwent a bowel management program for severe fecal incontinence or constipation show significant improvement in stool continence rates, patient-reported outcomes measures, and quality of life. A bowel management program (in-person or via telemedicine) is a feasible treatment strategy for adult patients who fail standard management of fecal incontinence or constipation and should be offered when appropriate. LEVEL OF EVIDENCE: III.

Redo posterior sagittal anorectoplasty for lateral mislocation in patients with anorectal malformations.

BACKGROUND: Children undergoing repair of an anorectal malformation (ARM) may have persistent soiling and/or constipation postoperatively. An anatomic reason should be sought; one of the causes for these problems that may require reoperation is mislocation of the rectum and anus outside of the muscle complex. METHODS: We reviewed our population of children who underwent re-do anorectoplasty surgery between 2014 and 2019. Indications for surgery and outcomes were recorded. RESULTS: Twelve patients had a lateral mislocation and underwent reoperation. There were no immediate complications in this subgroup. 9 of 10 patients are clean, and 4 are now able to have voluntary bowel movements. CONCLUSION: For patients who are found to have a significant lateral mislocation, we describe a new surgical technique that replaces the rectum and neo-anus directly in the midline through the muscle complex which may improve functional outcome.

Transanal-only Swenson-like pull-through for late diagnosed Hirschsprung disease.

Hirschsprung disease (HD) is an obstructive colonic process usually diagnosed in the neonatal period. A small subset of cases are diagnosed late, present with severe constipation without enterocolitis and have low rectosigmoid disease. A transanal-only pull-through is a well-described approach but in the newborn period risks a situation whereby the transition zone is higher than the sigmoid. We present our experience with the unique patient population of older HD patients in whom the transition zone was reliably reachable via a single-stage transanal approach, performed in prone position. Patients between 2 and 6 years of age with a rectal or sigmoid transition zone and minimal proximal colonic dilation can undergo a primary transanal pull-through surgical approach.