Determining the Optimal Technique for Bar Fixation in the Repair of Pectus Excavatum

Introduction: Pectus bar stabilizers are routinely used for bar fixation in the repair of pectus excavatum. We aimed to determine the optimum technique for bar fixation by reviewing our institutional experience with the use of bilateral, unilateral, and no stabilizer placement. Methods: Retrospective single pediatric center review of patients who underwent minimally invasive bar placement for pectus excavatum and subsequent bar removal between December 2001 and July 2019 was performed. Demographic data, details about the surgery, the number of bars and stabilizers used, and follow-up information were collected. Stabilizer-related complications included pain requiring stabilizer removal, surgical site infections (SSIs), and bar displacement. Data are presented as medians with interquartile ranges (IQRs) and frequencies with percentages. Results: A total of 561 patients were included. The cohort was predominantly male (83.1%, n = 466) with a median age at the time of bar placement of 15 years (IQR 12.4, 16.3) and a median Haller index of 3.8 (IQR 3.4, 4.5). Pain attributed to the stabilizer site that required removal was observed only in the bilateral stabilizer group (2.5%, n = 13). SSI related to the stabilizer site occurred in 1.8% (n = 9) of the bilateral stabilizer cases and 2.1% (n = 1) of the unilateral stabilizer cases. Bar displacement was observed in 0.6% (n = 3) of the bilateral stabilizer cases and 2 of those patients also had an SSI. There were no complications in the no stabilizer group. Conclusion: As the trend moves toward unilateral and no stabilizer use, we observe fewer cases of pain requiring stabilizer removal with no increase in bar displacements.

Structure-activity relationships of bensulfuron methyl and its derivatives as novel agents against drug-resistant Candida auris

With the emergence of the human pathogen Candida auris as a threat to human health, there is a strong demand to identify effective medicines to prevent the harm caused by such drug-tolerant human fungi. Herein, a series of 33 new derivatives of bensulfuron methyl (BSM) were synthesized and characterized by 1 H NMR, 13 C NMR, and HRMS. Among the target compounds, 8a possessed the best Ki value of 1.015 μM against C. auris acetohydroxyacid synthase (CauAHAS) and an MIC value of 6.25 μM against CBS10913, a clinically isolated strain of C. auris. Taken together the structures of BSM and the synthesized compounds, it was found that methoxy groups at both meta-position of pyrimidine ring are likely to provide desirable antifungal activities. Quantum calculations and molecular dockings were performed to understand the structure-activity relationships. The present study has hence provided some interesting clues for the discovery of novel antibiotics with this distinct mode of action.

SAGA Complex Subunit Hfi1 Is Important in the Stress Response and Pathogenesis of Cryptococcus neoformans

The Spt-Ada-Gcn Acetyltransferase (SAGA) complex is a highly conserved co-activator found across eukaryotes. It is composed of a number of modules which can vary between species, but all contain the core module. Hfi1 (known as TADA1 in Homo sapiens) is one of the proteins that forms the core module, and has been shown to play an important role in maintaining complex structural integrity in both brewer's yeast and humans. In this study we successfully identified the gene encoding this protein in the important fungal pathogen, Cryptococcus neoformans, and named it HFI1. The hfi1Δ mutant is highly pleiotropic in vitro, influencing phenotypes, ranging from temperature sensitivity and melanin production to caffeine resistance and titan cell morphogenesis. In the absence of Hfi1, the transcription of several other SAGA genes is impacted, as is the acetylation and deubiquination of several histone residues. Importantly, loss of the gene significantly impacts virulence in a murine inhalation model of cryptococcosis. In summary, we have established that Hfi1 modulates multiple pathways that directly affect virulence and survival in C. neoformans, and provided deeper insight into the importance of the non-enzymatic components of the SAGA complex.

Hypertrophic Pyloric Stenosis Protocol: A Single Center Study

BACKGROUND

Initial treatment of hypertrophic pyloric stenosis (HPS) is correction of electrolyte disturbances with fluid resuscitation. In 2015, our institution implemented a fluid resuscitation protocol based on previous data that focused on minimizing blood draws and allowing immediate ad libitum feeds postoperatively. Our aim was to describe the protocol and subsequent outcomes.

METHODS

We conducted a single-center retrospective review of patients diagnosed with HPS from 2016 to 2023. All patients were given ad libitum feeds postoperatively and discharged home after tolerating three consecutive feeds. The primary outcome was the postoperative hospital length of stay (LOS). Secondary outcomes included the number of preoperative labs drawn, time from arrival to surgery, time from surgery to initiation of feeds, time from surgery to full feeds, and re-admission rate.

RESULTS

The study included 333 patients. A total of 142 patients (42.6%) had electrolytic disturbances that required fluid boluses in addition to 1.5x maintenance fluids. The median number of lab draws was 1 (IQR 1,2), with a median time from arrival to surgery of 19.5 hours (IQR 15.3,24.9). The median time from surgery to first and full feed was 1.9 hours (IQR 1.2,2.7) and 11.2 hours (IQR 6.4,18.3), respectively. Patients had a median postoperative LOS of 21.8 hours (IQR 9.7,28.9). Re-admission rate within the first 30 postoperative days was 3.6% (n = 12) with 2.7% of re-admissions occurring within 72 hours of discharge. One patient required re-operation due to an incomplete pyloromyotomy.

DISCUSSION

This protocol is a valuable tool for perioperative and postoperative management of patients with HPS while minimizing uncomfortable intervention.

Infliximab Rescue Therapy in Pediatric Severe Colitis

INTRODUCTION

Clinical remission has been achieved with infliximab in patients with refractory ulcerative colitis (UC). However, there is conflicting data regarding its effectiveness as rescue therapy in adult acute severe colitis. Furthermore, pediatric inflammatory bowel disease (IBD) is associated with more severe disease that may be less amenable to attempted rescue. We reviewed our experience and outcomes with pediatric severe colitis after attempted inpatient rescue with infliximab.

METHODS

A single-institution, retrospective review was conducted of pediatric patients with UC or indeterminate colitis who received inpatient rescue infliximab therapy from 1/2000 to 1/2019. Rescue infliximab therapy was considered if a child failed non-biologic therapy or progressed to fulminant or toxic colitis. Primary outcome was failed therapy resulting in colectomy. A p-value of <0.05 determined significance.

RESULTS

Thirty patients met inclusion criteria. The median age at administration of rescue infliximab treatment was 14 years [IQR 13,17]. Rescue therapy with infliximab was successful in 33% (n = 10), while 67% (n = 20) underwent colectomy. Children on maintenance steroids were less likely to be successfully rescued with infliximab and require colectomy (p = 0.03). Children requiring colectomy had a longer hospital stay (p = 0.03), more abdominal radiographs (p = 0.01), and were on a longer duration of antibiotics (p = <0.01) compared to children who were successfully rescued with infliximab. There was no difference in baseline vital signs or laboratory abnormalities between the two groups.

CONCLUSION

In severe acute ulcerative or indeterminate colitis cases where infliximab has not been previously used, rescue infliximab can be used to avoid colectomy but has a high failure rate.

LEVEL OF EVIDENCE

IV.

TYPE OF STUDY

Retrospective study.

Institutional outcomes of blunt liver and splenic injury in the Arizona-Texas-Oklahoma-Memphis-Arkansas Consortium era

BACKGROUND

The Arizona-Texas-Oklahoma-Memphis-Arkansas Consortium practice management guideline was created to standardize management of blunt liver or spleen injury across pediatric trauma centers. We describe our outcomes since guideline adoption at our institution and hypothesize that blunt liver or spleen injury may be managed more expeditiously than currently reported without compromising safety.

METHODS

A retrospective cohort study was conducted on patients younger than 18 years presenting with blunt liver and/or splenic injuries from March 2016 to March 2021 at one participating center.

RESULTS

A total of 199 patients were included. There were no clinically relevant differences for age, body mass index, or sex among the cohort. Isolated splenic injuries (n = 91 [46%]) and motor vehicle collisions (n = 82 [41%]) were the most common injury and mechanism, respectively. The overall median length of stay (LOS) was 1.2 days (interquartile range, 0.45-3.3 days). Intensive care unit utilization was 23% (n = 46). There was no statistically significant difference in median LOS among patients with isolated solid organ injuries, regardless of injury grade. There were no readmissions associated with non-operative management.

CONCLUSION

The Arizona-Texas-Oklahoma-Memphis-Arkansas Consortium guideline fosters high rates of nonoperative management with low intensive care unit utilization and LOS while demonstrating safety in implementation, irrespective of injury grade.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level IV.

Long-Term Recurrence Rates and Patient Satisfaction after Repair of Pectus Excavatum

BACKGROUND

 Pectus excavatum deformities are usually repaired with a minimally invasive approach in which a metal bar is used to correct the chest wall abnormality. We aimed to evaluate long-term outcomes and patient satisfaction after surgical correction.

METHODS

 Patients who underwent pectus excavatum repair and subsequent bar removal at a single tertiary care center from January 2000 to December 2020 were identified. A retrospective chart review was performed, and a telephone survey was conducted to evaluate perceived inward chest movement, need for surgeon reevaluation, surgical reintervention, and overall satisfaction. Data are presented as medians with interquartile ranges (IQRs) and frequencies with percentages.

RESULTS

 A total of 583 patients were included. The survey response rate was 26.2% (n = 153). The respondents were predominantly male (80.4%, n = 123) with a median age at surgical correction of 14.9 years (IQR 12.9, 16.1) and a median Haller index (HI) of 3.8 (IQR 3.4, 4.5). Median time to bar removal was 2.9 years (IQR 2.5, 3.0) with a median age at removal of 17.7 years (IQR 15.5, 19.0). Median time from surgery to survey follow-up was 9.6 years (IRQ 5.0, 11.4) with respondents having a median age at follow-up of 25 years (IQR 22.0, 28.4). The satisfaction rate was 96.7% (n = 148) with a reintervention rate of 2.0% (n = 3). The perceived inward chest movement was 30.7% (n = 47) with 12.8% (n = 6) of those requesting surgical reevaluation.

CONCLUSION

 There is a high level of satisfaction many years after correction of pectus excavatum and bar removal. With the advent of cryoablative therapy since 2017, patient satisfaction improved by experience of less postoperative pain. Reintervention rate is low despite some patients reporting a perceived chest wall inward movement.

Satisfaction With Same-Day Discharge After Laparoscopic Appendectomy for Nonperforated Appendicitis

INTRODUCTION

Same-day discharge (SDD) after laparoscopic appendectomy for acute nonperforated appendicitis is safe, without an increased rate of postoperative complications, emergency department visits, or readmissions. We aimed to evaluate caregiver satisfaction with this protocol.

METHODS

Patients discharged on the day of laparoscopic appendectomy for nonperforated acute appendicitis were identified between January 2022 and August 2022. Surveys to evaluate satisfaction with the protocol were distributed to the caregivers via email or text message 96 h after discharge. Telephone surveys were conducted if there were no responses to the initial online survey. The surveys assessed comfort with SDD, postoperative pain control adequacy, postoperative provider contact, and overall satisfaction. The protocol focused on avoidance of narcotics in the postoperative period and immediate return to a regular diet.

RESULTS

A total of 255 cases of nonperforated acute appendicitis underwent SDD. The survey response rate was 50.6% (n = 129). Most respondents were Caucasian (69.0%, n = 89) and male (51.9%, n = 67) with a median age of 12.0 y (IQR 8.9,14.7). The median postoperative length of hospital stay was 3.8 h (interquartile range [IQR] 3.2,4.8). The overall satisfaction rate was 91.5%, with 118 caregivers feeling satisfied with SDD. Most caregivers felt comfortable with the SDD protocol (89.9%, n = 116), with 22.5% (n = 29) calling a medical provider postoperatively. Approximately nine out of 10 caregivers reported that pain was adequately controlled (91.5%, n = 118). In contrast, those that were dissatisfied reported issues with pain control and anxiety with SDD after a surgical procedure.

CONCLUSIONS

Caregiver satisfaction and comfort with same-day discharge following laparoscopic appendectomy is high with appropriate anticipatory guidance and preoperative education.

Multicenter Assessment of Cryoanalgesia Use in Minimally Invasive Repair of Pectus Excavatum: A 20-center Retrospective Cohort Study

OBJECTIVE

To assess the clinical implications of cryoanalgesia for pain management in children undergoing minimally invasive repair of pectus excavatum (MIRPE).

BACKGROUND

MIRPE entails significant pain management challenges, often requiring high postoperative opioid use. Cryoanalgesia, which blocks pain signals by temporarily ablating intercostal nerves, has been recently utilized as an analgesic adjunct. We hypothesized that the use of cryoanalgesia during MIRPE would decrease postoperative opioid use and length of stay (LOS).

MATERIALS AND METHODS

A multicenter retrospective cohort study of 20 US children's hospitals was conducted of children (age below 18 years) undergoing MIRPE from January 1, 2014, to August 1, 2019. Differences in total postoperative, inpatient, oral morphine equivalents per kilogram, and 30-day LOS between patients who received cryoanalgesia versus those who did not were assessed using bivariate and multivariable analysis. P value <0.05 is considered significant.

RESULTS

Of 898 patients, 136 (15%) received cryoanalgesia. Groups were similar by age, sex, body mass index, comorbidities, and Haller index. Receipt of cryoanalgesia was associated with lower oral morphine equivalents per kilogram (risk ratio=0.43, 95% confidence interval: 0.33-0.57) and a shorter LOS (risk ratio=0.66, 95% confidence interval: 0.50-0.87). Complications were similar between groups (29.8% vs 22.1, P =0.07), including a similar rate of emergency department visit, readmission, and/or reoperation.

CONCLUSIONS

Use of cryoanalgesia during MIRPE appears to be effective in lowering postoperative opioid requirements and LOS without increasing complication rates. With the exception of preoperative gabapentin, other adjuncts appear to increase and/or be ineffective at reducing opioid utilization. Cryoanalgesia should be considered for patients undergoing this surgery.

Weight loss and clinical outcomes following primary versus secondary Roux-en-Y gastric bypass: a multi-institutional experience

BACKGROUND

Revisional bariatric surgeries are increasing for weight recurrence and return of co-morbidities. Herein, we compare weight loss and clinical outcomes following primary Roux-en-Y Gastric Bypass (P-RYGB), adjustable gastric banding to RYGB (B-RYGB), and sleeve gastrectomy to RYGB (S-RYGB) to determine if primary versus secondary RYGB offer comparable benefits.

METHODS

Participating institutions' EMRs and MBSAQIP databases were used to identify adult patients who underwent P-/B-/S-RYGB from 2013 to 2019 with a minimum one-year follow-up. Weight loss and clinical outcomes were assessed at 30 days, 1 year, and 5 years. Our multivariable model controlled for year, institution, patient and procedure characteristics, and excess body weight (EBW).

RESULTS

768 patients underwent RYGB: P-RYGB n = 581 [75.7%]; B-RYGB n = 106 [13.7%]; S-RYGB n = 81 [10.5%]. The number of secondary RYGB procedures increased in recent years. The most common indications for B-RYGB and S-RYGB were weight recurrence/nonresponse (59.8%) and GERD (65.4%), respectively. Mean time from index operation to B-RYGB or S-RYGB was 8.9 and 3.9 years, respectively. After adjusting for EBW, 1 year %TWL (total weight loss) and %EWL (excess weight loss) were greater after P-RYGB (30.4%, 56.7%) versus B-RYGB (26.2%, 49.4%) or S-RYGB (15.6%, 37%). Overall comorbidity resolution was comparable. Secondary RYGB patients had a longer adjusted mean length of stay (OR 1.17, p = 0.071) and a higher risk of pre-discharge complications or 30-day reoperation.

CONCLUSION

Primary RYGB offers superior short-term weight loss outcomes compared to secondary RYGB, with decreased risk of 30-day reoperation.

Management of primary spontaneous pneumothorax in children: A single institution protocol analysis

BACKGROUND

The Midwest Pediatric Surgery Consortium (MWPSC) suggested a simple aspiration of primary spontaneous pneumothorax (PSP) protocol, failing which, Video-Assisted Thoracoscopic Surgery (VATS) should be considered. We describe our outcomes using this suggested protocol.

METHODS

A single institution retrospective analysis was conducted on patients between 12 and 18 years who were diagnosed with PSP from 2016 to 2021. Initial management involved aspiration alone with a ≤12 F percutaneous thoracostomy tube followed by clamping of the tube and chest radiograph at 6 h. Success was defined as ≤2 cm distance between chest wall and lung at the apex and no air leak when the clamp was released. VATS followed if aspiration failed.

RESULTS

Fifty-nine patients were included. Median age was 16.8 years (IQR 15.9, 17.3). Aspiration was successful in 33% (20), while 66% (39) required VATS. The median LOS with successful aspiration was 20.4 h (IQR 16.8, 34.8), while median LOS after VATS was 3.1 days (IQR 2.6, 4). In comparison, in the MWPSC study, the mean LOS for those managed with a chest tube after failed aspiration was 6.0 days (±5.5). Recurrence after successful aspiration was 45% (n = 9), while recurrence after VATS was 25% (n = 10). Median time to recurrence after successful aspiration was sooner than that of the VATS group [16.6 days (IQR 5.4, 19.2) vs. 389.5 days (IQR 94.1, 907.0) p = 0.01].

CONCLUSION

Simple aspiration is safe and effective initial management for children with PSP, although most will require VATS. However, early VATS reduces length of stay and morbidity.

LEVEL OF EVIDENCE

IV. Retrospective study.

Evaluating caretaker satisfaction with same-day discharge after gastrostomy tube placement

BACKGROUND

Same-day discharge (SDD) after laparoscopic gastrostomy tube (G-tube) placement, using written and video-based preoperative education, has been our standard institutional practice since 2017. We aim to evaluate caretaker satisfaction with this protocol.

METHODS

All patients planned for SDD after G-tube placement from February 2021-February 2022 were identified. Chart review was performed to identify demographic information, successful same-day discharge or reason for postoperative admission, time to first postoperative feed, length of stay (LOS), and complications requiring emergency department evaluation, readmission, or reoperation. Telephone follow-up at two weeks postoperatively was conducted to evaluate satisfaction with the SDD protocol.

RESULTS

Forty-nine patients were eligible for SDD with a median age of 1.1 years [0.7, 4.4]. Forty-two (86%) patients were successfully discharged the same day with a median LOS of 7.5 h [6.7, 8.1], and 7 (14%) were admitted postoperatively for further education or emesis with a median LOS of 30.4 h [26.9, 31.2]. Median time to initiation of feeds was 2.3 h [1.7, 2.9]. 8 (16%) patients were evaluated in the emergency department within 30 days postoperatively, resulting in two re-admissions: one for peri‑stomal erythema and fever requiring oral antibiotics at 21 days and one for G-tube dislodgement requiring reoperation and replacement at 28 days. On two-week telephone follow-up, 42 caretakers (100%) felt that their education was adequate for same-day discharge and felt comfortable with the same-day discharge protocol. Six (14%) caretakers stated their child's pain was not well controlled at some point between discharge and survey follow-up, and three caretakers (7%) called a provider within the first 24 h for issues with pain. Forty-one caretakers (98%) expressed satisfaction going home the day of surgery.

CONCLUSION

Caretaker satisfaction and comfort with same-day discharge following laparoscopic G-tube placement are high, ascribed to comprehensive preoperative education and anticipatory guidance.

TYPE OF STUDY

Prognostic.

LEVEL OF EVIDENCE

Level 1.

Pre-hospital CPR after traumatic arrest: Outcomes at a level 1 pediatric trauma center

BACKGROUND

The survival of traumatic cardiopulmonary arrest (TCA) requiring pre-hospital cardiopulmonary resuscitation (P-CPR) is abysmal across age groups. We aim to describe the mechanisms of injury and outcomes of children suffering from TCA leading to P-CPR at our institution.

METHODS

A retrospective review was conducted to identify children ages 0-17 years who suffered TCA leading to P-CPR at our institution between 5/2009 and 3/2020. For analysis, patients were stratified into those still undergoing CPR at arrival and those who attained pre-hospital return of spontaneous circulation (ROSC). Primary outcome was discharge alive from the hospital.

RESULTS

P-CPR was initiated for 48 patients who had TCA; 23 had pre-hospital ROSC. Of the 25 children undergoing CPR at presentation, none survived to discharge. The median duration of CPR, from initiation to time of death declaration was 34 min [29,50]. Seventeen patients died after resuscitation attempts in the ED, while 8 died after admission to the PICU. Of the 23 patients who attained pre-hospital ROSC, 6 survived to discharge. All survivors required intensive rehabilitation services at discharge and at most recent follow-up, 5 had residual deficits requiring medical attention.

CONCLUSION

There are poor outcomes in children with pre-hospital traumatic cardiopulmonary arrest, particularly in those without pre-hospital ROSC. These data further support the need for standardized guidelines for resuscitation in children with traumatic cardiopulmonary arrest.

Unique Evaluation and Management Considerations for Adolescents with Late Gynecologic and Colorectal Issues in the Setting of Anorectal Malformations

STUDY OBJECTIVE

There is little guidance for managing pubertally identified Mullerian anomalies in patients with anorectal malformations (ARMs). We sought to assess these unique issues.

DESIGN

Retrospective review SETTING: Single-institution study PARTICIPANTS: Natal female patients aged 10-25, with an ARM, cloaca, or exstrophy, who presented from 2009 to 2019 with a gynecologic concern were included.

INTERVENTION

Data collection was performed and included the presenting problem, psychological evaluation, fertility and sexuality concerns, and management strategies for these problems.

MAIN OUTCOME MEASURES

The main outcome was unique needs that had to be addressed in the young adult population and the type of colorectal and gynecological procedures needed on representation.

RESULTS

Twelve patients were identified; all had gynecologic concerns. Ten had ARMs, including cloaca (n = 3) and cloacal exstrophy (n = 5). Median age at representation was 14.6 years (IQR = 12.7, 15.3). Colorectal revisions included posterior sagittal anorectoplasty (n = 1), resection of bowel attached to urogenital sinus (n = 1), and appendicostomy revision (n = 1). Gynecologic issues included dysmenorrhea (n = 8), obstructed Mullerian anomaly (n = 6), and introital stenosis (n = 5). Behavioral health concerns (n = 9) and fertility/sexuality concerns (n = 4) were identified. Median time from first visit to reconstruction was 1.5 years (IQR = 0.5, 1.5), providing multiple visits to achieve consensus among patients and providers before intervention, including vaginal or introital repair (n = 5) and hysterectomy of obstructed uterine horns (n = 3).

CONCLUSIONS

Goal-directed follow-up is required before surgical management to identify psychological and reproductive issues in patients with ARMs who have gynecologic concerns. Patient input and psychologic consultation are helpful for patients requiring staged reconstruction.

Testicular torsion disparities in the pediatric population

BACKGROUND

There are disparate findings in the literature on the impact of race and insurance status on gonadal loss in testicular torsion. We sought to determine if race or levels of social vulnerability influence the rate of torsion or gonadal loss.

METHODS

Retrospective cross-sectional review between December 2017 and September 2019. Social vulnerability index was dichotomized using the 75th percentile. Primary outcome was the diagnosis of testicular torsion.

RESULTS

515 patients were included. There was no difference in median age, torsion diagnosis, and orchiectomy rate between the two institutions. Black/African American patients were >3 times more likely than Caucasian patients to be diagnosed with TT when controlled for dichotomized SVI, insurance, and age (OR 3.39, 95% CI 1.74 - 6.61, p < 0.01).

CONCLUSION

Black/African American children have an increased risk of testicular torsion. Despite these patients having higher levels of social vulnerability, it was not associated.

Evaluating the risk of peri-umbilical hernia after sutured or sutureless gastroschisis closure

INTRODUCTION

We evaluate the incidence, outcomes, and management of peri‑umbilical hernias after sutured or sutureless gastroschisis closure.

METHODS

A retrospective, longitudinal follow-up of neonates with gastroschisis who underwent closure at 11 children's hospitals from 2013 to 2016 was performed. Patient encounters were reviewed through 2019 to identify the presence of a peri‑umbilical hernia, time to spontaneous closure or repair, and associated complications.

RESULTS

Of 397 patients, 375 had follow-up data. Sutured closure was performed in 305 (81.3%). A total of 310 (82.7%) infants had uncomplicated gastroschisis. Peri-umbilical hernia incidence after gastroschisis closure was 22.7% overall within a median follow-up of 2.5 years [IQR 1.3,3.9], and higher in those with uncomplicated gastroschisis who underwent primary vs. silo assisted closure (53.0% vs. 17.2%, p< 0.001). At follow-up, 50.0% of sutureless closures had a persistent hernia, while 16.4% of sutured closures had a postoperative hernia of the fascial defect (50.0% vs. 16.4%, p< 0.001). Spontaneous closure was observed in 38.8% of patients within a median of 17 months [9,26] and most frequently observed in those who underwent a sutureless primary closure (52.2%). Twenty-seven patients (31.8%) underwent operative repair within a median of 13 months [7,23.5]. Rate and interval of spontaneous closure or repair were similar between the sutured and sutureless closure groups, with no difference between those who underwent primary vs. silo assisted closure.

CONCLUSION

Peri-umbilical hernias after sutured or sutureless gastroschisis closure may be safely observed similar to congenital umbilical hernias as spontaneous closure occurs, with minimal complications and no additional risk with either closure approach.

LEVELS OF EVIDENCE

Level II.

Proteomics dataset from 26th Dynasty Egyptian mummified remains sampled using minimally invasive skin sampling tape strips

Paleoproteomics typically involves the destructive sampling of precious bioarchaeological materials. This analysis aims to investigate the proteins identifiable via nanoLC-MS/MS from highly degraded 26th Dynasty Egyptian mummified human remains (NMR.29.1-8) after non-destructive sampling with commercially available dermatology-grade skin sampling tape strips. A collection of cranial and other bone fragments were sampled with the tape strips then subsequently analysed using a shotgun proteomics approach. The number of proteins identified using this method ranged from 18 to 437 at a peptide FDR of <1%. Deamidation ratios were assessed using an in-house R script, with asparagine deamidation averaging ∼20–30% and glutamine deamidation averaging ∼15–25%.

Single institution review of Mini-ACE® low-profile appendicostomy button for antegrade continence enema administration

PURPOSE

Malone antegrade continence enemas (MACE) provide a conduit in which the patient can achieve improved continence, be clean of stool, and gain independence in maintaining bowel function. The Mini-ACE® is a low-profile balloon button that is used to facilitate the administration of antegrade enemas. We sought to describe our practice and short-term outcomes.

METHODS

This work is a retrospective review of the Mini-ACE® appendicostomy button from April 2019 to March 2021, with follow-up concluding in October 2021. Patient demographics, colorectal diagnoses, and outcomes were examined.

RESULTS

Forty-three patients underwent Mini-ACE® placement; 22 (51%) were male. The average age at Mini-ACE® insertion was 9.2 years (range 3-20 years). The most common diagnoses were functional constipation in 19 (44%), anorectal malformation in 15 (35%), and Hirschsprung disease in 3 (7%), spinal differences 3 (7%). There were no intra-operative complications, but 5 (12%) required prolapse resection. The median length of stay was two days (IQR 1, 4). Patients achieved self-catheterization at 4.5 [3,7] months from MACE creation, with 38 children (88%) reporting excellent success in remaining clean of stool.

CONCLUSION

The Mini-ACE® appears to be a safe and low-profile option for antegrade continence enema access. Further research is needed directly comparing complications and patient satisfaction rates between different MACE devices and overall quality of life.

LEVEL OF EVIDENCE

Level IV.

Umbilical access in laparoscopic surgery in infants less than 3 months: A single institution retrospective review

INTRODUCTION

Umbilical access in laparoscopic surgery has been cited as a factor for increased complications in low-birth-weight infants and those less than three months old. In a previous series, 10.6% of pediatric surgeons reported complications in this population associated with umbilical access, citing carbon dioxide (CO₂) embolism as the most common complication. To further examine the safety of this technique, we report our outcomes with blunt transumbilical laparoscopic access at our institution over four years.

METHODS

A retrospective review was performed of patients less than three months of age who underwent laparoscopic pyloromyotomy or inguinal hernia repair from 2016 to 2019. Operative reports, anesthesia records, and postoperative documentation were reviewed for complications related to umbilical access. Complications included bowel injury, vascular injury, umbilical vein cannulation, CO₂ embolism, umbilical surgical site infection (SSI), umbilical hernia requiring repair, and death.

RESULTS

Of 365 patients, 246 underwent laparoscopic pyloromyotomy, and 119 underwent laparoscopic inguinal hernia repairs. Median age at operation was 5.9 weeks [4.3,8.8], and median weight was 3.9 kg [3.4,4.6]. Nine complications (2.5%) occurred: 5 umbilical SSIs (1.4%), 1 bowel injury upon entry requiring laparoscopic repair (0.2%), 1 incisional hernia repair 22 days postoperatively (0.2%), and 2 cases of hypotension and bradycardia upon insufflation that resolved with desufflation (0.5%). There were no intraoperative mortalities or signs/symptoms of CO₂ embolism.

CONCLUSION

In this series, umbilical access for laparoscopic surgery in neonates less than three months of age was safe, with minimal complications. Although concern for umbilical vessel injury, cannulation, and CO₂ embolism exists, these complications are not exclusively associated with umbilical access technique.

Evaluation of a fluid resuscitation protocol for patients with hypertrophic pyloric stenosis

INTRODUCTION

We previously developed an institutional, evidence-based fluid resuscitation protocol for neonates with infantile hypertrophic pyloric stenosis (HPS) based on the severity of electrolyte derangement on presentation. We aim to evaluate this protocol to determine its efficacy in reducing the number of preoperative lab draws, time to electrolyte correction, and overall length of stay.

METHODS

A single center, retrospective review of 319 infants with HPS presenting with electrolyte derangement from 2008 to 2020 was performed; 202 patients managed pre-protocol (2008-2014) and 117 patients managed per our institutional fluid resuscitation algorithm (2016-2020). The number of preoperative lab draws, time to electrolyte correction, and length of stay before and after protocol implementation was recorded.

RESULTS

Use of a fluid resuscitation algorithm decreased the number of infants who required four or more preoperative lab draws (20% vs. 6%) (p < .01), decreased median time to electrolyte correction between the pre and post protocol cohorts (15.1 h [10.6, 22.3] vs. 11.9 h [8.5, 17.9]) (p < .01), and decreased total length of hospital stay (49.0 h [40.3, 70.7] vs. 45.7 h [34.3, 65.9]) (p < .05).

CONCLUSION

Implementation of a fluid resuscitation algorithm for patients presenting with hypertrophic pyloric stenosis decreases the frequency of preoperative lab draws, time to electrolyte correction, and total length of hospital stay. Use of a fluid resuscitation protocol may decrease discomfort through fewer preoperative lab draws and shorter length of stay while setting clear expectations and planned intervention for parents.

LEVEL OF EVIDENCE

III - Retrospective comparative study.

How does flecainide impact RyR2 channel function?

Flecainide, a cardiac class 1C blocker of the surface membrane sodium channel (NaV1.5), has also been reported to reduce cardiac ryanodine receptor (RyR2)-mediated sarcoplasmic reticulum (SR) Ca2+ release. It has been introduced as a clinical antiarrhythmic agent for catecholaminergic polymorphic ventricular tachycardia (CPVT), a condition most commonly associated with gain-of-function RyR2 mutations. Current debate concerns both cellular mechanisms of its antiarrhythmic action and molecular mechanisms of its RyR2 actions. At the cellular level, it targets NaV1.5, RyR2, Na+/Ca2+ exchange (NCX), and additional proteins involved in excitation-contraction (EC) coupling and potentially contribute to the CPVT phenotype. This Viewpoint primarily addresses the various direct molecular actions of flecainide on isolated RyR2 channels in artificial lipid bilayers. Such studies demonstrate different, multifarious, flecainide binding sites on RyR2, with voltage-dependent binding in the channel pore or voltage-independent binding at distant peripheral sites. In contrast to its single NaV1.5 pore binding site, flecainide may bind to at least four separate inhibitory sites on RyR2 and one activation site. None of these binding sites have been specifically located in the linear RyR2 sequence or high-resolution structure. Furthermore, it is not clear which of the inhibitory sites contribute to flecainide's reduction of spontaneous Ca2+ release in cellular studies. A confounding observation is that flecainide binding to voltage-dependent inhibition sites reduces cation fluxes in a direction opposite to physiological Ca2+ flow from SR lumen to cytosol. This may suggest that, rather than directly blocking Ca2+ efflux, flecainide can reduce Ca2+ efflux by blocking counter currents through the pore which otherwise limit SR membrane potential change during systolic Ca2+ efflux. In summary, the antiarrhythmic effects of flecainide in CPVT seem to involve multiple components of EC coupling and multiple actions on RyR2. Their clarification may identify novel specific drug targets and facilitate flecainide's clinical utilization in CPVT.

Gating of RYR2 channels from the arrhythmic RYR2-P2328S mouse heart and some unexpected actions of flecainide

The P2328S mutation in mice is associated with arrhythmia and spontaneous diastolic calcium release in atrial and ventricular myocytes and there is a corresponding leftward shift in the Ca2+-activation curve for mutant RYR2 channels from homozygous mouse hearts (Salvage et al. 2019. J Cell Sci. https://doi.org/10.1242/jcs.229039). P2328 is located in helical domain 1 (HD1) of RYR2. Local structural changes likely result when structurally active proline residues are replaced by structurally inert serine residues. We speculate that local structural changes in HD1 lead to sequential intradomain and interdomain stearic changes through the protein to the distant channel gate, which favor the open pore conformation. The drug flecainide prevents arrhythmia in humans and mouse models of CPVT by blocking NaV1.5 and RYR2 channels. Conventionally, flecainide blocks RYR2 channels in a voltage-dependent manner. We did not observe voltage-dependent pore block. This was possibly because, in contrast to previous studies, the only channel modulators that we used to produce end-diastolic control channel activity were 1 µM cytoplasmic Ca2+ and 1 mM luminal Ca2+. We observed previously unreported, voltage-independent increases in WT and P2328S channel activity at low flecainide concentrations, followed by a decline in activity at higher concentrations. The increase in activity dominated the effect of flecainide on P2328S channels. These effects suggested high-affinity flecainide binding to an activation site and lower-affinity binding to an inhibition site, both distant from the channel pore (Salvage et al. 2021. Cells. https://doi.org/10.3390/cells10082101). Unlike channel block by flecainide, the drug under our conditions stabilized intrinsic sub-conductance activity at +40 mV and -40 mV. Since flecainide effectively reduces CPVT arrythmia clinically and in animal models, we conclude that voltage-independent inhibition and voltage-dependent channel block prevail under cellular conditions. However, channel activation is important to note as it may be unmasked in other circumstances such as acquired cardiac disorders, mutations, or additional drug applications.

AICAR transformylase/IMP cyclohydrolase (ATIC) is essential for de novo purine biosynthesis and infection by Cryptococcus neoformans

The fungal pathogen Cryptococcus neoformans is a leading cause of meningoencephalitis in the immunocompromised. As current antifungal treatments are toxic to the host, costly, limited in their efficacy, and associated with drug resistance, there is an urgent need to identify vulnerabilities in fungal physiology to accelerate antifungal discovery efforts. Rational drug design was pioneered in de novo purine biosynthesis as the end products of the pathway, ATP and GTP, are essential for replication, transcription, and energy metabolism, and the same rationale applies when considering the pathway as an antifungal target. Here, we describe the identification and characterization of C. neoformans 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase/5'-inosine monophosphate cyclohydrolase (ATIC), a bifunctional enzyme that catalyzes the final two enzymatic steps in the formation of the first purine base inosine monophosphate. We demonstrate that mutants lacking the ATIC-encoding ADE16 gene are adenine and histidine auxotrophs that are unable to establish an infection in a murine model of virulence. In addition, our assays employing recombinantly expressed and purified C. neoformans ATIC enzyme revealed K_m values for its substrates AICAR and 5-formyl-AICAR are 8-fold and 20-fold higher, respectively, than in the human ortholog. Subsequently, we performed crystallographic studies that enabled the determination of the first fungal ATIC protein structure, revealing a key serine-to-tyrosine substitution in the active site, which has the potential to assist the design of fungus-specific inhibitors. Overall, our results validate ATIC as a promising antifungal drug target.

Fundoplication without esophagocrural sutures: Long-term follow-up of a randomized clinical trial

INTRODUCTION

We previously conducted a randomized trial that showed a lack of need for esophagocrural (EC) sutures during fundoplication when no esophageal dissection was performed. There was no difference in wrap herniation or other complications in the group without EC sutures at a median 1.5 years of follow-up. In this follow-up study, we aim to evaluate long-term symptom control and complication profiles in these patients.

METHODS

106 patients were randomized and participated in the original trial. We were primarily concerned with identification of late complications and persistence of symptoms. Presently, we conducted a retrospective chart review and a telephone follow-up survey at a minimum of 6.5 years after fundoplication.

RESULTS

100 patients were alive at late follow-up and 70% of caregivers responded to the telephone survey. 53% of patients were male; 76% were Caucasian. Of these children, 39 (56%) received four EC sutures, while 31 (44%) did not. Follow-up was conducted at a median of 8.7 years [IQR 8.2,9.7] post-fundoplication. Late wrap herniation was not demonstrated radiographically on chart review or caregiver report in either group. The rate of residual reflux symptoms, post-operative hospitalizations for pneumonia, failure to thrive (FTT), and brief resolved unexplained event (BRUE) were also similar between groups.

CONCLUSION

Long-term follow-up in children who underwent fundoplication without esophagocrural sutures demonstrates no difference in symptom management or subsequent hospitalizations at a minimum of 6.5-year follow-up.

LEVEL OF EVIDENCE

II (follow-up of a randomized controlled trial).

Laparoscopic Gastrostomy in Infants During an Open Abdominal Procedure: A Novel Approach

Introduction: Infants with intra-abdominal pathology necessitating open abdominal surgery may also require placement of a gastrostomy tube (GT). Use of laparoscopy provides better visualization for gastrostomy placement and lowers the risk of complications compared with an open approach. We describe a series of patients who underwent laparoscopic GT placement at the time of an open abdominal procedure. Methods: All patients who underwent an open abdominal procedure with concurrent laparoscopic gastrostomy from January 2010 to June 2020 were reviewed. Descriptive statistics were performed with categorical variables reported as proportions and continuous variables reported as medians with interquartile range [IQR]. Results: Twelve patients were included; 8 (67.5%) were male. The median age at time of surgery was 10 weeks [IQR 6, 14], with a median weight of 4.1 kg [IQR 3.4, 4.8]. Ten patients had the laparoscope placed through the open incision, whereas 2 had the laparoscope placed through a separate incision. Median operative time was 106 minutes [IQR 80, 125]. There were no intraoperative complications. Postoperative complications included surgical site infection in 5 (41.7%), leaking around the GT in 3 (25%), and malfunction of the tube in 1 (8.3%). One patient required reoperation 28 days postoperatively due to malfunction. Conclusion: Laparoscopic GT can be safely performed at the time of an open abdominal procedure, and frequently through the same incision, harnessing the benefits of a laparoscopic approach even when an open incision is needed.

Management of Hirschsprung associated enterocolitis-How different are practice strategies? An international pediatric endosurgery group (IPEG) survey

INTRODUCTION

Hirschsprung's-associated enterocolitis (HAEC) is a common post-operative problem for patients with Hirschsprung disease (HSCR). However, treatment strategies remain variable among providers, institutions, and even nations. The purpose of this study was to identify differences in treatment patterns for HAEC.

METHODS

A questionnaire was distributed to members of the International Pediatric Endoscopic Group (IPEG) community that focused on HSCR and HAEC management strategies. Questionnaire responses were collected via the Research Electronic Data Capture (RedCap).

RESULTS

178 responses were obtained: 30% from North America, 20% South America, 20% Europe, 26% Asia, and 4% from Australia. 37% had a dedicated pediatric colorectal center. After diagnosis, 53% send patients home with irrigations, while 29% perform a primary PT before discharge; the type of PT varied between Soave (50%), Swenson (25%) and Duhamel (13%). Only 29 respondents (17%) stated their institution had guidelines for HAEC management; however, inpatient treatments were fairly consistent: 95% performed rectal irrigations, 93% obtained an abdominal radiograph, and 72% held feeds; 55% taught families irrigations before discharge. Utilization of Botulinum (BT) injections was mixed: 36% never utilized BT injections, 33% only used BT if irrigations were not tolerated, and 16% only injected BT for recurrent episodes. Preventative HAEC measures were also varied and included anal dilations (44%), prophylactic antibiotics (34%), probiotics (29%), and routine home irrigations (22%).

CONCLUSION

There is wide variation of care in managing enterocolitis episodes in patients with Hirschsprung disease. Further research leading to consensus guidelines and standardization practices can help improve the care for these patients.

LEVEL OF EVIDENCE

V TYPE OF STUDY: Treatment study/ survey.

Short and long term outcomes of using cryoablation for postoperative pain control in patients after pectus excavatum repair

INTRODUCTION

We report the findings of a three-year prospective observational study elucidating long-term symptoms and complications of patients who underwent minimally invasive pectus excavatum repair with intercostal nerve cryoablation with specific attention to postoperative pain control associated with the cryoablation technique.

METHODS

Surveys were administered to patients who underwent bar placement for pectus excavatum with intercostal nerve cryoablation from 2017 to 2021 regarding pain scores, pain medication usage, and limitations to activity beginning on the day of surgery, on the day of discharge, and at two-week and three-month follow-up.

RESULTS

Of 110 patients, forty-eight (44%) completed the discharge survey; sharp pain and pressure on the first postoperative night were the most described pain characteristics, most frequently in the middle of the chest. On follow-up, 55% of patients reported tolerable residual pain at two weeks and 41% at three months, with 25% requiring intermittent pain medication at three months. There were three readmissions for inadequate pain control and 110 calls to the surgery clinic by three-month follow-up, most commonly for persistent pain and frequent popping sensation with movement.

DISCUSSION

Although cryoablation is an excellent pain control modality, these data suggest that patients underreport functional symptoms and experience more frequent discomfort and alteration of daily living activities.

Psychosocial factors affecting quality of life in patients with anorectal malformation and Hirschsprung disease-a qualitative systematic review

INTRODUCTION

Little is known about psychosocial and behavioral factors that impact the quality of life of patient's with anorectal malformations (ARM) and Hirschsprung disease (HSCR). We aimed to highlight the psychosocial, emotional, and behavioral themes that affect these patients.

METHODS

A qualitative literature review of articles published between 1980 and 2019 was performed. Articles that reported quality of life (QoL) measures not directly related to bowel function and incorporated data on patients aged 0-21 years old were included. Data were separated based on distinct developmental time points.

RESULTS

In the neonatal period, parents relayed uncertainty about the future and feeling overwhelmed by lack of social support. Difficulties with anxiety, peer rejection, and behavioral problems were noted in primary grades, while adolescents experienced low self-confidence, poor body image, and depression. Young adults expressed hesitancy to engage in romantic relationships or sexual activity. Lack of long-term follow-up, an incomplete transition to adult healthcare, and lack of psychology services leave young adults without guidance to manage a chronic condition.

CONCLUSION

Multiple psychosocial stressors are present in the lives of ARM and HSCR patients. Provision of developmentally matched medical, psychological, and community-based supports for ARM and HSCR patients and their families can lead to improved QoL.

Behind the mask: extended use of surgical masks is not associated with increased risk of surgical site infection

PURPOSE

COVID-19 has prompted significant policy change, with critical attention to the conservation of personal protective equipment (PPE). An extended surgical mask use policy was implemented at our institution, allowing use of one disposable mask per each individual, per day, for all the cases. We investigate the clinical impact of this policy change and its effect on the rate of 30-day surgical site infection (SSI).

METHODS

A single-institution retrospective review was performed for all the elective pediatric general surgery cases performed pre-COVID from August 2019 to October 2019 and under the extended mask use policy from August 2020 to October 2020. Procedure type, SSI within 30 days, and postoperative interventions were recorded.

RESULTS

Four hundred and eighty-eight cases were reviewed: 240 in the pre-COVID-19 cohort and 248 in the extended surgical mask use cohort. Three SSIs were identified in the 2019 cohort, and two in the 2020 cohort. All postoperative infections were superficial and resolved within 1 month of diagnosis with oral antibiotics. There were no deep space infections, readmissions, or infections requiring re-operation.

CONCLUSION

Extended surgical mask use was not associated with increased SSI in this series of pediatric general surgery cases and may be considered an effective and safe strategy for resource conservation with minimal clinical impact.

Evaluation of a Symptom-Based Algorithm for Managing Battery Ingestions in Children

OBJECTIVES

 While complications from battery ingestion can be severe, especially with the emergence of stronger battery elements, not all ingestions require prompt removal. We aim to evaluate a symptom-focused algorithm for battery ingestion that emphasizes observation over intervention to investigate its safety.

MATERIALS AND METHODS

 Patients were identified through a query of foreign-body ingestion radiographs obtained between 2017 and 2020. A retrospective chart review was then performed of all patients who presented with button battery ingestions to identify compliance with our algorithm, overall outcomes, and complications.

RESULTS

 In total, 2% of all radiographs (44/2,237) demonstrated button battery ingestions. The median age of patients was 3.8 years (interquartile range, 2.6-5.3). Most batteries were found in the stomach (64%, n = 28), but were also identified in the esophagus (14%, n = 6), small bowel (14%, n = 6), and colon (9%, n = 4). All esophageal batteries were managed with immediate endoscopic retrieval. Ten gastric batteries were not managed per protocol, with seven admitted for observation despite being asymptomatic and repeat abdominal X-rays demonstrating persistent gastric location of the battery. Four patients underwent esophagogastroduodenoscopy; however, in two patients the battery had migrated past the stomach prior to intervention. All small bowel batteries and three of four asymptomatic colon batteries were managed per protocol; one patient had additional imaging that demonstrated battery passage.

CONCLUSION

 Adherence to a symptom-focused protocol for conservative management of button battery ingestions beyond the gastroesophageal junction is safe and frequently does not require admission, serial imaging, or intervention.

Review of Perioperative Prophylactic Antibiotic Use during Laparoscopic Cholecystectomy and Subsequent Surgical Site Infection Development at a Single Children's Hospital

OBJECTIVES

 With the rise of antibiotic resistance, the use of prophylactic preoperative antibiotics (PPA) has been questioned in cases with low rates of surgical site infection (SSI). We report PPA usage and SSI rates after elective laparoscopic cholecystectomy at our institution.

MATERIALS AND METHODS

 A retrospective review of children younger than 18 years who underwent elective outpatient laparoscopic cholecystectomy between July 2010 and August 2020 was performed. Demographic, preoperative work-up, antibiotic use, intraoperative characteristics, and SSI data were collected via chart review. SSI was defined as clinical signs of infection that required antibiotics within 30 days of surgery.

RESULTS

 A total of 502 patients met the inclusion criteria; 50% were preoperatively diagnosed with symptomatic cholelithiasis, 47% with biliary dyskinesia, 2% with hyperkinetic gallbladder, and 1% with gallbladder polyp(s). The majority were female (78%) and Caucasian (80%). In total, 60% (n = 301) of patients received PPA, while 40% (n = 201) did not; 1.3% (n = 4) of those who received PPA developed SSI, compared with 5.5% (n = 11) of those who did not receive PPA (p = 0.01). Though PPA use was associated with a 77% reduction in the risk of SSI in multivariate analysis (p = 0.01), all SSIs were superficial. One child required readmission for intravenous antibiotics, while the remainder were treated with outpatient antibiotics. Gender, age, body mass index, ethnicity, and preoperative diagnosis did not influence the likelihood of receiving PPA.

CONCLUSION

 Given the relatively low morbidity of the superficial SSI, conservative use of PPA is advised to avoid contributing to antibiotic resistance.

Triazolopyrimidine herbicides are potent inhibitors of Aspergillus fumigatus acetohydroxyacid synthase and potential antifungal drug leads

Aspergillus fumigatus is a fungal pathogen whose effects can be debilitating and potentially fatal in immunocompromised patients. Current drug treatment options for this infectious disease are limited to just a few choices (e.g. voriconazole and amphotericin B) and these themselves have limitations due to potentially adverse side effects. Furthermore, the likelihood of the development of resistance to these current drugs is ever present. Thus, new treatment options are needed for this infection. A new potential antifungal drug target is acetohydroxyacid synthase (AHAS; EC 2.2.1.6), the first enzyme in the branched chain amino acid biosynthesis pathway, and a target for many commercial herbicides. In this study, we have expressed, purified and characterised the catalytic subunit of AHAS from A. fumigatus and determined the inhibition constants for several known herbicides. The most potent of these, penoxsulam and metosulam, have K_i values of 1.8 ± 0.9 nM and 1.4 ± 0.2 nM, respectively. Molecular modelling shows that these compounds are likely to bind into the herbicide binding pocket in a mode similar to Candida albicans AHAS. We have also shown that these two compounds inhibit A. fumigatus growth at a concentration of 25 µg/mL. Thus, AHAS inhibitors are promising leads for the development of new anti-aspergillosis therapeutics.

Outpatient Botulinum Injections for Early Obstructive Symptoms in Patients with Hirschsprung Disease

INTRODUCTION

Botulinum toxin (BT) injections may play a role in preventing Hirschsprung associated enterocolitis (HAEC) episodes related to internal anal sphincter (IAS dysfunction). Our aim was to determine the association of outpatient BT injections for early obstructive symptoms on the development of HAEC.

METHODS

A retrospective review of children who underwent definitive surgery for Hirschsprung disease (HSCR) from July 2010 - July 2020 was performed. The timing from pull-through to first HAEC episode and to first BT injection was recorded. Primary analysis focused on the rate of HAEC episodes and timing between episodes in patients who did and did not receive BT injections.

RESULTS

Eighty patients were included. Sixty patients (75%) were male, 15 (19%) were diagnosed with trisomy 21, and 58 (72.5%) had short-segment disease. The median time to pull-through was 150 days (IQR 16, 132). Eight patients (10%) had neither an episode of HAEC or BT injections and were not included in further analysis. Forty-six patients (64%) experienced at least one episode of HAEC, while 64 patients (89%) had at least one outpatient BT injection. Compared to patients who never received BT injections (n = 9) and those who developed HAEC prior to BT injections (n = 35), significantly fewer patients who received BT injections first (n = 28) developed enterocolitis (P < 0.001), with no patient developing more than one HAEC episode.

CONCLUSION

Outpatient BT is associated with decreased episodes of HAEC and increased interval between HAEC episodes requiring inpatient treatment. Scheduling outpatient BT injections to manage obstructive symptoms may be beneficial after pull-through for HSCR.

Structural features of Cryptococcus neoformans bifunctional GAR/AIR synthetase may present novel antifungal drug targets

Cryptococcus neoformans is a fungus that causes life-threatening systemic mycoses. During infection of the human host, this pathogen experiences a major change in the availability of purines; the fungus can scavenge the abundant purines in its environmental niche of pigeon excrement, but must employ de novo biosynthesis in the purine-poor human CNS. Eleven sequential enzymatic steps are required to form the first purine base, IMP, an intermediate in the formation of ATP and GTP. Over the course of evolution, several gene fusion events led to the formation of multifunctional purine biosynthetic enzymes in most organisms, particularly the higher eukaryotes. In C. neoformans, phosphoribosyl-glycinamide synthetase (GARs) and phosphoribosyl-aminoimidazole synthetase (AIRs) are fused into a bifunctional enzyme, while the human ortholog is a trifunctional enzyme that also includes GAR transformylase. Here we functionally, biochemically, and structurally characterized C. neoformans GARs and AIRs to identify drug targetable features. GARs/AIRs are essential for de novo purine production and virulence in a murine inhalation infection model. Characterization of GARs enzymatic functional parameters showed that C. neoformans GARs/AIRs have lower affinity for substrates glycine and PRA compared with the trifunctional metazoan enzyme. The crystal structure of C. neoformans GARs revealed differences in the glycine- and ATP-binding sites compared with the Homo sapiens enzyme, while the crystal structure of AIRs shows high structural similarity compared with its H. sapiens ortholog as a monomer but differences as a dimer. The alterations in functional and structural characteristics between fungal and human enzymes could potentially be exploited for antifungal development.

Flecainide Paradoxically Activates Cardiac Ryanodine Receptor Channels under Low Activity Conditions: A Potential Pro-Arrhythmic Action

Cardiac ryanodine receptor (RyR2) mutations are implicated in the potentially fatal catecholaminergic polymorphic ventricular tachycardia (CPVT) and in atrial fibrillation. CPVT has been successfully treated with flecainide monotherapy, with occasional notable exceptions. Reported actions of flecainide on cardiac sodium currents from mice carrying the pro-arrhythmic homozygotic RyR2-P2328S mutation prompted our explorations of the effects of flecainide on their RyR2 channels. Lipid bilayer electrophysiology techniques demonstrated a novel, paradoxical increase in RyR2 activity. Preceding flecainide exposure, channels were mildly activated by 1 mM luminal Ca²⁺ and 1 µM cytoplasmic Ca²⁺, with open probabilities (P_o) of 0.03 ± 0.01 (wild type, WT) or 0.096 ± 0.024 (P2328S). Open probability (P_o) increased within 0.5 to 3 min of exposure to 0.5 to 5.0 µM cytoplasmic flecainide, then declined with higher concentrations of flecainide. There were no such increases in a subset of high P_o channels with P_o ≥ 0.08, although P_o then declined with ≥5 µM (WT) or ≥50 µM flecainide (P2328S). On average, channels with P_o < 0.08 were significantly activated by 0.5 to 10 µM of flecainide (WT) or 0.5 to 50 µM of flecainide (P2328S). These results suggest that flecainide can bind to separate activation and inhibition sites on RyR2, with activation dominating in lower activity channels and inhibition dominating in more active channels.

A single institution experience with Laparoscopic Hernia repair in 791 children

INTRODUCTION

There are many described technique to performing laparoscopic inguinal hernia repair in children. We describe our outcomes using a percutaneous internal ring suturing technique.

METHODS

A retrospective review of patients under 18 years old who underwent repair between January 2014 - March 2019 was performed. A percutaneous internal ring suturing technique, involving hydro-dissection of the peritoneum, percutaneous suture passage, and cauterization of the peritoneum in the sac prior to high ligation, was used. p < 0.05 was considered significant during the analysis.

RESULTS

791 patients were included. The median age at operation was 1.9 years (IQR 0.37, 5.82). The median operative time for a unilateral repair was 21 min (IQR 16, 28), while the median time for a bilateral repair was 30.5 min (IQR 23, 41). In total, 3 patients required conversion to an open procedure (0.4%), 4 (0.6%) experienced post-operative bleeding, 9 (1.2%) developed a wound infection, and iatrogenic ascent of testis occurred in 10 (1.3%) patients. Twenty patients (2.5%) developed a recurrent hernia. All but two were re-repaired laparoscopically.

CONCLUSIONS

The use of percutaneous internal ring suturing for laparoscopic repair of inguinal hernias in the pediatric population is safe and effective with a low rate of complications and recurrence.

Prediction of Paroxysmal Atrial Fibrillation From Complexity Analysis of the Sinus Rhythm ECG: A Retrospective Case/Control Pilot Study

Paroxysmal atrial fibrillation (PAF) is the most common cardiac arrhythmia, conveying a stroke risk comparable to persistent AF. It poses a significant diagnostic challenge given its intermittency and potential brevity, and absence of symptoms in most patients. This pilot study introduces a novel biomarker for early PAF detection, based upon analysis of sinus rhythm ECG waveform complexity. Sinus rhythm ECG recordings were made from 52 patients with (n = 28) or without (n = 24) a subsequent diagnosis of PAF. Subjects used a handheld ECG monitor to record 28-second periods, twice-daily for at least 3 weeks. Two independent ECG complexity indices were calculated using a Lempel-Ziv algorithm: R-wave interval variability (beat detection, BD) and complexity of the entire ECG waveform (threshold crossing, TC). TC, but not BD, complexity scores were significantly greater in PAF patients, but TC complexity alone did not identify satisfactorily individual PAF cases. However, a composite complexity score (h-score) based on within-patient BD and TC variability scores was devised. The h-score allowed correct identification of PAF patients with 85% sensitivity and 83% specificity. This powerful but simple approach to identify PAF sufferers from analysis of brief periods of sinus-rhythm ECGs using hand-held monitors should enable easy and low-cost screening for PAF with the potential to reduce stroke occurrence.

Herbicides That Target Acetohydroxyacid Synthase Are Potent Inhibitors of the Growth of Drug-Resistant Candida auris

Acetohydroxyacid synthase (AHAS, EC 2.2.1.6), the first enzyme in the branched chain amino acid biosynthesis pathway, is the target for more than 50 commercially available herbicides, and is a promising target for antimicrobial drug discovery. Herein, we have expressed and purified AHAS from Candida auris, a newly identified human invasive fungal pathogen. Thirteen AHAS inhibiting herbicides have K_i values of <2 μM for this enzyme, with the most potent having K_i values of <32 nM. Six of these compounds exhibited MIC₅₀ values of <1 μM against C. auris (CBS10913 strain) grown in culture, with bensulfuron methyl (BSM) being fungicidal and the most potent (MIC₅₀ of 0.090 μM) in defined minimal media. The MIC₅₀ value increases to 0.90 μM in media enriched by the addition of branched-chain amino acids at the expected concentration in the blood serum. The sessile MIC₅₀ for BSM is 0.6 μM. Thus, it is also an excellent inhibitor of the growth of C. auris biofilms. BSM is nontoxic in HEK-293 cells at concentrations >100 μM and thus possesses a therapeutic index of >100. These data suggest that targeting AHAS is a viable strategy for treating C. auris infections.

Surveying purine biosynthesis across the domains of life unveils promising drug targets in pathogens

Purines play an integral role in cellular processes such as energy metabolism, cell signaling and encoding the genetic makeup of all living organisms-ensuring that the purine metabolic pathway is maintained across all domains of life. To gain a deeper understanding of purine biosynthesis via the de novo biosynthetic pathway, the genes encoding purine metabolic enzymes from 35 archaean, 69 bacterial and 99 eukaryotic species were investigated. While the classic elements of the canonical purine metabolic pathway were utilized in all domains, a subset of familiar biochemical roles was found to be performed by unrelated proteins in some members of the Archaea and Bacteria. In the Bacteria, a major differentiating feature of de novo purine biosynthesis is the increasing prevalence of gene fusions, where two or more purine biosynthesis enzymes that perform consecutive biochemical functions in the pathway are encoded by a single gene. All species in the Eukaryota exhibited the most common fusions seen in the Bacteria, in addition to new gene fusions to potentially increase metabolic flux. This complexity is taken further in humans, where a reversible biomolecular assembly of enzymes known as the purinosome has been identified, allowing short-term regulation in response to metabolic cues while expanding on the benefits that can come from gene fusion. By surveying purine metabolism across all domains of life, we have identified important features of the purine biosynthetic pathway that can potentially be exploited as prospective drug targets.

Structures of fungal and plant acetohydroxyacid synthases

Acetohydroxyacid synthase (AHAS), also known as acetolactate synthase, is a flavin adenine dinucleotide-, thiamine diphosphate- and magnesium-dependent enzyme that catalyses the first step in the biosynthesis of branched-chain amino acids¹. It is the target for more than 50 commercial herbicides². AHAS requires both catalytic and regulatory subunits for maximal activity and functionality. Here we describe structures of the hexadecameric AHAS complexes of Saccharomyces cerevisiae and dodecameric AHAS complexes of Arabidopsis thaliana. We found that the regulatory subunits of these AHAS complexes form a core to which the catalytic subunit dimers are attached, adopting the shape of a Maltese cross. The structures show how the catalytic and regulatory subunits communicate with each other to provide a pathway for activation and for feedback inhibition by branched-chain amino acids. We also show that the AHAS complex of Mycobacterium tuberculosis adopts a similar structure, thus demonstrating that the overall AHAS architecture is conserved across kingdoms.

Kalparinol, a Salvialane (Isodaucane) Sesquiterpenoid Derived from Native Australian Dysphania Species That Suggests a Putative Biogenetic Link to Zerumbone

Dysphania is a genus of plants endemic to the Australian continent, occurring primarily in arid and temperate zones. Despite their prevalence, very little in the way of phytochemical and/or bioactivity investigation of native Dysphania has been performed. Herein reported is the isolation and elucidation of (6E,9E)-zerumbone epoxide and a hitherto unreported isomer, (6Z,9E)-zerumbone epoxide, from D. kalpari. In addition, a novel isodaucane sesquiterepene, kalparinol, was isolated from both D. kalpari and D. rhadinostachya. The coisolation of the humulene and isodaucane skeletons, combined with the lack of any cadalane systems, could suggest an alternate novel biogenetic pathway originating from zerumbone, which is unlike any other proposals for the isodaucene system.

Broadening the spectrum of fluorescent protein tools for use in the encapsulated human fungal pathogen Cryptococcus neoformans

Green fluorescent protein (GFP) and its counterparts are modern molecular biology research tools indispensable in many experimental systems. Within fungi, researchers studying Saccharomyces cerevisiae and other model ascomycetes have access to a wide variety of fluorescent proteins. Unfortunately, many of these tools have not crossed the phylum divide into the Basidiomycota, where only GFP S65T, Venus, Ds-Red, and mCherry are currently available. To address this, we searched the literature for potential candidates to be expressed in the human fungal pathogen Cryptococcus neoformans and identified a suite of eight more modern fluorescent proteins that span the visible spectrum. A single copy of each fluorophore was heterologously expressed in Safe Haven 1 and their fluorescence intensities compared in this encapsulated yeast. mTurquoise2, mTFP1, Clover, mNeonGreen, mRuby3, and Citrine were highly visible under the microscope, whereas Superfolder GFP and mMaroon1 were not. Expressed fluorophores did not impact growth or virulence as demonstrated by an in vitro spotting assay and murine inhalation model, respectively.

Humulene Diepoxides from the Australian Arid Zone Herb Dysphania: Assignment of Aged Hops Constituents

Dysphania is an abundant genus of plants, many of which are endemic to the Australian continent, occurring primarily in arid and temperate zones. Despite their prevalence, very few investigations into the phytochemistry of native Dysphania have been undertaken. Described herein, is the isolation and elucidation of two enantiomeric diastereomers of humulene diepoxide C from D. kalpari and D. rhadinostachya, of which unassigned diastereomers of humulene diepoxide C have been previously reported as components in beer brewed from aged hops. In addition, two (+)-humulene diepoxiols (humulene diepoxiol C-I and C-II) were isolated from D. rhadinostachya. Analysis of Chinook hops oil confirmed the presence of both humulene diepoxide C-I and C-II as trace components, and in turn enabled GC-MS peak assignment to the relative stereochemistry. Anticancer assays did not reveal any significant activity for the (+)-humulene diepoxides. Antifungal assays showed good activity against a drug-resistant strain of C. auris, with MIC₅₀ values of 8.53 and 4.91 μm obtained for (+)-humulene diepoxide C-I and C-II, respectively.

Ion channel gating in cardiac ryanodine receptors from the arrhythmic RyR2-P2328S mouse

Mutations in the cardiac ryanodine receptor Ca²⁺ release channel (RyR2) can cause deadly ventricular arrhythmias and atrial fibrillation (AF). The RyR2-P2328S mutation produces catecholaminergic polymorphic ventricular tachycardia (CPVT) and AF in hearts from homozygous RyR2^{P2328S/P2328S} (denoted RyR2^S/S) mice. We have now examined P2328S RyR2 channels from RyR2^S/S hearts. The activity of wild-type (WT) and P2328S RyR2 channels was similar at a cytoplasmic [Ca²⁺] of 1 mM, but P2328S RyR2 was significantly more active than WT at a cytoplasmic [Ca²⁺] of 1 µM. This was associated with a >10-fold shift in the half maximal activation concentration (AC₅₀) for Ca²⁺ activation, from ∼3.5 µM Ca²⁺ in WT RyR2 to ∼320 nM in P2328S channels and an unexpected >1000-fold shift in the half maximal inhibitory concentration (IC₅₀) for inactivation from ∼50 mM in WT channels to ≤7 μM in P2328S channels, which is into systolic [Ca²⁺] levels. Unexpectedly, the shift in Ca²⁺ activation was not associated with changes in sub-conductance activity, S2806 or S2814 phosphorylation or the level of FKBP12 (also known as FKBP1A) bound to the channels. The changes in channel activity seen with the P2328S mutation correlate with altered Ca²⁺ homeostasis in myocytes from RyR2^S/S mice and the CPVT and AF phenotypes.This article has an associated First Person interview with the first author of the paper.

The application of Lempel-Ziv and Titchener complexity analysis for equine telemetric electrocardiographic recordings

The analysis of equine electrocardiographic (ECG) recordings is complicated by the absence of agreed abnormality classification criteria. We explore the applicability of several complexity analysis methods for characterization of non-linear aspects of electrocardiographic recordings. We here show that complexity estimates provided by Lempel-Ziv ’76, Titchener’s T-complexity and Lempel-Ziv ’78 analysis of ECG recordings of healthy Thoroughbred horses are highly dependent on the duration of analysed ECG fragments and the heart rate. The results provide a methodological basis and a feasible reference point for the complexity analysis of equine telemetric ECG recordings that might be applied to automate detection of equine arrhythmias in equine clinical practice.

Antifungal benzo[b]thiophene 1,1-dioxide IMPDH inhibitors exhibit pan-assay interference (PAINS) profiles

Fungi cause serious life-threatening infections in immunocompromised individuals and current treatments are now complicated by toxicity issues and the emergence of drug resistant strains. Consequently, there is a need for development of new antifungal drugs. Inosine monophosphate dehydrogenase (IMPDH), a key component of the de novo purine biosynthetic pathway, is essential for growth and virulence of fungi and is a potential drug target. In this study, a high-throughput screen of 114,000 drug-like compounds against Cryptococcus neoformans IMPDH was performed. We identified three 3-((5-substituted)-1,3,4-oxadiazol-2-yl)thio benzo[b]thiophene 1,1-dioxides that inhibited Cryptococcus IMPDH and also possessed whole cell antifungal activity. Analogs were synthesized to explore the SAR of these hits. Modification of the fifth substituent on the 1,3,4-oxadiazole ring yielded compounds with nanomolar in vitro activity, but with associated cytotoxicity. In contrast, two analogs generated by substituting the 1,3,4-oxadiazole ring with imidazole and 1,2,4-triazole gave reduced IMPDH inhibition in vitro, but were not cytotoxic. During enzyme kinetic studies in the presence of DTT, nucleophilic attack of a free thiol occurred with the benzo[b]thiophene 1,1-dioxide. Two representative compounds with substitution at the 5 position of the 1,3,4-oxadiazole ring, showed mixed inhibition in the absence of DTT. Incubation of these compounds with Cryptococcus IMPDH followed by mass spectrometry analysis showed non-specific and covalent binding with IMPDH at multiple cysteine residues. These results support recent reports that the benzo[b]thiophene 1,1-dioxides moiety as PAINS (pan-assay interference compounds) contributor.

Titan cells formation in Cryptococcus neoformans is finely tuned by environmental conditions and modulated by positive and negative genetic regulators

The pathogenic fungus Cryptococcus neoformans exhibits morphological changes in cell size during lung infection, producing both typical size 5 to 7 μm cells and large titan cells (> 10 μm and up to 100 μm). We found and optimized in vitro conditions that produce titan cells in order to identify the ancestry of titan cells, the environmental determinants, and the key gene regulators of titan cell formation. Titan cells generated in vitro harbor the main characteristics of titan cells produced in vivo including their large cell size (>10 μm), polyploidy with a single nucleus, large vacuole, dense capsule, and thick cell wall. Here we show titan cells derived from the enlargement of progenitor cells in the population independent of yeast growth rate. Change in the incubation medium, hypoxia, nutrient starvation and low pH were the main factors that trigger titan cell formation, while quorum sensing factors like the initial inoculum concentration, pantothenic acid, and the quorum sensing peptide Qsp1p also impacted titan cell formation. Inhibition of ergosterol, protein and nucleic acid biosynthesis altered titan cell formation, as did serum, phospholipids and anti-capsular antibodies in our settings. We explored genetic factors important for titan cell formation using three approaches. Using H99-derivative strains with natural genetic differences, we showed that titan cell formation was dependent on LMP1 and SGF29 genes. By screening a gene deletion collection, we also confirmed that GPR4/5-RIM101, and CAC1 genes were required to generate titan cells and that the PKR1, TSP2, USV101 genes negatively regulated titan cell formation. Furthermore, analysis of spontaneous Pkr1 loss-of-function clinical isolates confirmed the important role of the Pkr1 protein as a negative regulator of titan cell formation. Through development of a standardized and robust in vitro assay, our results provide new insights into titan cell biogenesis with the identification of multiple important factors/pathways.

The Long History of the Diverse Roles of Short ORFs: sPEPs in Fungi

Since the completion of the genome sequence of the model eukaryote Saccharomyces cerevisiae, there have been significant advancements in the field of genome annotation, in no small part due to the availability of datasets that make large-scale comparative analyses possible. As a result, since its completion there has been a significant change in annotated ORF size distribution in this first eukaryotic genome, especially in short ORFs (sORFs) predicted to encode polypeptides less than 150 amino acids in length. Due to their small size and the difficulties associated with their study, it is only relatively recently that these genomic features and the sORF-encoded peptides (sPEPs) they encode have become a focus of many researchers. Yet while this class of peptides may seem new and exciting, the study of this part of the proteome is nothing new in S. cerevisiae, a species where the biological importance of sPEPs has been elegantly illustrated over the past 30 years. Here the authors showcase a range of different sORFs found in S. cerevisiae and the diverse biological roles of their encoded sPEPs, and provide an insight into the sORFs found in other fungal species, particularly those pathogenic to humans.

The beer and biofuels laboratory: A report on implementing and supporting a large, interdisciplinary, yeast-focused course-based undergraduate research experience

Course-integrated Undergraduate Research Experiences (CUREs) involve large numbers of students in real research. We describe a late-year microbiology CURE in which students use yeast to address a research question around beer brewing or synthesizing biofuel; the interdisciplinary student-designed project incorporates genetics, bioinformatics, biochemistry, analytical chemistry, and microbiology. Students perceived significant learning gains around multiple technical and "becoming a scientist" aspects of the project. The project is demanding for both the students and the academic implementers. We examine the rich landscape of support and interaction that this CURE both encourages and requires while also considering how we can support the exercise better and more sustainably. The findings from this study provide a picture of a CURE implementation that has begun to reach the limits of both the students' and the academics' capacities to complete it. © 2018 by The International Union of Biochemistry and Molecular Biology, 46(3):213-222, 2018.