Cloacal Dysgenesis Sequence in a Preterm Neonate

BACKGROUND Cloaca malformations result from a disproportion of apoptosis, cell growth, and maturation. The range of cloacal malformations is extensive and diverse, with a lack of a straightforward classification system. Cloacal dysgenesis sequence (CDS), also known as urorectal septum malformation sequence, is a rare cloaca variant described as the absence of a perineal orifice. Prenatal magnetic resonance imaging and antenatal ultrasounds may reveal a cloacal malformation; however, many patients are not diagnosed with cloacal malformation until birth. CASE REPORT We present a case of a female neonate delivered by a 23-year-old G2P1T1A0L0 mother who had received comprehensive prenatal care. During pregnancy, bilateral multicystic dysplastic kidneys were identified prenatally, leading to the in utero placement of a vesicoamniotic shunt. The physical exam revealed a distended abdomen with reduced abdominal musculature and laxity, ascites, a vesicoamniotic shunt in place, absent urethra, ambiguous genitalia with no vaginal opening, no perineal opening, and clubfoot. Abdominal radiograph showed findings consistent with significant abdominal ascites. An exploratory laparotomy was performed that included diverting colostomy, mucous fistula creation, tube vaginostomy, removal of the vesicoamniotic shunt, and suprapubic tube placement. The patient recovered well from this operation with no complications. CONCLUSIONS CDS is an uncommon condition in pediatric patients, and although sonographic findings can reveal urinary tract abnormalities, prenatal imaging might not always identify CDS. Our case underscores the uniqueness of the case and the significance of early detection and immediate medical and surgical intervention.

Establishment of a successful robotic pediatric general surgery practice

Robotic-assisted surgery (RAS) has a variety of theoretical advantages, including tremor filtration, optimal visualization, and improvement of surgeon ergonomics. Though it has achieved wide application in pediatric urology, the majority of pediatric general surgeons do not employ RAS. This study reports our institution's experience with RAS on a pediatric general surgery team. Following IRB approval, a retrospective review of all pediatric patients at our academic children's hospital who underwent RAS between 2017 and 2022 for pediatric general surgical conditions was performed. Patient demographics, operation performed, operating time, complications, and recovery were evaluated. A total of 159 children underwent RAS, increasing from 10 patients in 2017 to 59 patients in 2022. The median age and weight were 15.3 years and 76.4 kg, and 121 (76.1%) were female. The application of RAS was successful in all cases. There were no intraoperative complications and no conversions to an open approach. Eleven patients (6.9%) had unplanned presentations to the emergency department within 30 days. Five of these patients (3.1%) required admission to the hospital. This study demonstrates that the application of RAS in an academic pediatric general surgery practice is feasible and safe. The application of RAS to pediatric general surgery should continue to increase as operative teams increase their experience and comfort.Level of evidence Level IV.

Case report: Duplicated appendicitis with history of cloacal exstrophy causing bowel obstruction

INTRODUCTION

Cloacal and bladder exstrophy are rare embryological defects that can cause developmental disruption of surrounding organ structures, the pelvis, spinal cord, and small intestines being the most commonly affected. Duplicated appendix is another rare embryological defect that has historically caused confusing clinical presentations. Our case highlights a rare instance of a patient with cloacal exstrophy who presented with a bowel obstruction and an associated inflamed duplicated appendix.

CASE PRESENTATION

A newborn male is born with omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex. As primary surgical reconstruction was pursued, the patient was found to have a non-inflamed duplicated appendix, which was left unremoved. In the following months, the patient experienced episodes of small bowel obstruction, eventually requiring surgical intervention. During this operation, the duplicated appendix was noted to be inflamed, prompting removal of both appendices.

DISCUSSION

This case highlights the increased prevalence of duplicated appendix in a patient with cloacal exstrophy, as well as the utility of prophylactic appendectomy for patients incidentally found to have a duplicated appendix intraoperatively. The duplicated appendix may lead to increased rates of complications and atypical presentation of appendicitis, supporting the practice of prophylactic appendectomy in patients with an incidentally found duplicated appendix.

CONCLUSION

We suggest clinicians be aware of the association and potentially atypical presentation of appendicitis in patients with a duplicated appendix, particularly in the setting of cloacal exstrophy. The decision to prophylactically remove an incidentally found, non-inflamed duplicated appendix may be beneficial in preventing confusing clinical presentations and future complications.

What animal model should I use to study necrotizing enterocolitis?

Unfortunately, we are all too familiar with the statement: "Necrotizing enterocolitis remains the leading cause of gastrointestinal surgical emergency in preterm neonates". It's been five decades since the first animal models of necrotizing enterocolitis (NEC) were described. There remains much investigative work to be done on identifying various aspects of NEC, ranging from the underlying mechanisms to treatment modalities. Experimental NEC is mainly focused on a rat, mouse, and piglet models. Our aim is to not only highlight the pros and cons of these three main models, but to also present some of the less-used animal models that have contributed to the body of knowledge about NEC. Choosing an appropriate model is essential to conducting effective research and answering the questions asked. As such, this paper reviews some of the variations that come with each model.

Milky pericardial effusion causing tamponade in a neonate after extracorporeal membrane oxygenation cannulation

Cardiac tamponade is a known life-threatening complication of extracorporeal membrane oxygenation (ECMO), often secondary to hemopericardium from major vascular or cardiac perforation. We present the unique case of a neonate with a milky pericardial effusion causing tamponade after ECMO cannulation, managed successfully with pericardial window. Understanding ECMO physiology and its effect on the classic presentation of tamponade is critical and can prevent delays in diagnosis. While hemopericardium is most commonly seen in these cases, findings of a non-bloody, milky effusion should prompt further workup for infection, chylopericardium or total parenteral nutrition-associated pericardial effusion, as the appropriate management can mitigate immediate and potential long-term sequelae.

Multiple Perianal Epidermal Cysts Found in a Case of Lowe Syndrome: A Case Report and Review of the Literature

BACKGROUND Lowe syndrome, also known as oculocerebrorenal syndrome, is a rare genetic condition caused by an X-linked mutation of the OCRL1 gene, with an estimated prevalence in the general population of approximately 1 in 500 000. It is a multisystem disorder most commonly affecting the eyes, central nervous system, and kidneys. These commonly manifest as congenital cataracts, intellectual disability, and proximal renal dysfunction (Fanconi-type). Epidermal lesions are an uncommon manifestation of this condition, and the association is not completely understood. CASE REPORT Here we present a case of a 9-year-old boy with Lowe syndrome who presented with multiple cystic masses found in the perianal region. An excision was then performed to remove the masses and found that the lesions were epidermal cysts, which are infrequently found in Lowe syndrome. After excision, the patient recovered uneventfully without complications. CONCLUSIONS While epidermal cysts are an uncommon manifestation that have been documented, our case remains unique given the location and associated symptoms of the lesions. At presentation, the constellation of pain and perianal masses was concerning for a malignant etiology. However, after diagnostic imaging was performed, these lesions were found to be epidermal cysts, an infrequent manifestation of Lowe syndrome. Few previous case reports described cystic lesions in association with Lowe syndrome, and none, to our knowledge, have described multiple symptomatic perianal lesions. This case is important to consider because epidermal cystic lesions can be found with this presentation and should be considered on differential diagnoses for dermatologic findings in Lowe syndrome patients.

Short-term outcomes of thoracoscopic versus open lobectomy for congenital lung malformations

PURPOSE

Thoracoscopic and open approaches for the management of congenital lung malformations (CLM) has been debated. The aim of this study is to compare 30-day outcomes for non-emergent lobectomies in children.

METHODS

The National Surgical Quality Improvement Program-Pediatric database was queried for patients undergoing CLM resection from 2013 to 2020. Outcomes were compared by operative technique in an intention-to-treat model and then propensity matched.

RESULTS

2157 patients met inclusion criteria and underwent non-emergent pulmonary lobectomy for CLM. The intended operative approach was thoracoscopic in 57.7% of patients. Patients in the open group compared to the thoracoscopic were more likely to be born premature, have chronic lung disease, require preoperative oxygen support, and be ventilator dependent. After propensity matching, there was no statistically significant difference in 30-day mortality, unplanned readmission, and other complications between the thoracoscopic and open groups. Thoracoscopic approach was associated with a shorter length of stay. The proportion of cases approached via thoracoscopy increased over time from 48.8% in 2013 to 69.9% in 2020.

CONCLUSIONS

This large multicenter retrospective matched analysis demonstrates thoracoscopic lobectomy in children has similar favorable 30-day outcomes and shorter length of stay for the non-emergent management of CLM, compared to open thoracotomy.

LEVEL OF EVIDENCE

Level III.

Are pediatric surgery fellowship websites ready for the changing paradigms in the virtual interview era?

Purpose

With the COVID-19 pandemic, in-person fellowship interviews were curtailed, leading candidates to seek information from other resources. Our main purposes were (1) to determine what information recent participants in the match needed to evaluate programs and (2) to assess which of these were available online.

Methods

A focus group of ten recent graduates/applicants identified information that was important in choosing a fellowship program. In August 2020 and December 2021, websites belonging to the American Pediatric Surgical Association (APSA) and individual programs were assessed.

Results

Recent applicants identified 55 pieces of information considered important to their decision making. Of 57 pediatric surgery fellowships, 98% were listed on APSA's website. Program descriptions on APSA's website listed on average 60% of program information desired by applicants. All listed fellowship director, accreditation status, faculty list, and current fellow(s). Other descriptors frequently noted were alumni (95%), graduate's board performance (83%), ECMO exposure (77%), and curriculum (70%). Information desired but less frequently available were fellow case logs (63%), trauma center designation (53%), burn center designation (40%), research opportunities (30%), candidate interview assistance (25%), and supplemental fellowships (12%). There were 7% of program descriptions that were not updated for at least a year.

Conclusions

APSA and individual program websites were complimentary. Websites often lacked data that applicants sought to inform their rank list. To best adapt to the evolving virtual interview paradigm, we suggest reporting key information on a central APSA website with more nuanced information available via links to program specific websites.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44186-023-00104-w.

A 12-Year-Old Girl with Juvenile Granulosa Cell Tumor of the Ovary, Presenting with Adolescent Hyperprolactinemia, Galactorrhea, and Amenorrhea

BACKGROUND Juvenile-type granulosa cell tumors (JGCTs) are a rare subtype of sex cord stromal tumor with a characteristic histology that is commonly found in the first 3 decades of life. It most commonly presents with symptoms of hyperestrogenism, which may present as precocious pseudopuberty or as menstruation-related symptoms, allowing for early detection of the tumor. CASE REPORT We present the case of a 12-year-old girl who presented to her primary care provider (PCP) with secondary amenorrhea with intermittent abdominal pain, who underwent an ultrasound for further evaluation, which revealed a large incidental pelvic mass. She was admitted to the Emergency Department (ED) and had findings of galactorrhea and hyperprolactinemia on examination. Imaging studies demonstrated a large ovarian mass measuring 15.0×9.0×18.8 cm that was resected, and subsequent pathology results showed JGCT stage 1A. CONCLUSIONS Prognosis of granulosa cell tumors (GCT) largely depends on its initial size, stage at diagnosis, residual tumors after surgery, and the subtype of GCT. If the patient is of reproductive age, fertility-sparing surgical options must be considered and patients must be regularly monitored for recurrence. JGCTs can present with minimal to no symptoms of precocious puberty in young girls but may present with amenorrhea, which may be considered normal for their developmental age. Although JGCTs are rare, they are important to include in differential diagnoses of younger female patients with abdominal pain, especially if accompanied by hormonal irregularities.

An Unusual Case of Primary Ileal Trichobezoar Causing Intussusception

Patient: Male, 8-year-old

Final Diagnosis: Intussusception

Symptoms: Abdominal pain • nausea • vomiting

Medication: —

Clinical Procedure: —

Specialty: Surgery

Objective Personality Determination: A Useful Addition to the Traditional Process of Pediatric Surgical Fellow Selection

BACKGROUND

Selection of pediatric surgical trainees is a multifaceted process heavily influenced by in-person interviews to determine personality makeup and institutional compatibility. We present our experience in utilizing a validated personality inventory in the selection of our candidates.

METHODS

All applicants selected for an in-person interview for the 2020 Pediatric Surgery Match were offered the Big Five Inventory (BFI) questionnaire. An initial rank order list (ROL) was formulated employing application information and in-person interview score. A reformulated ROL was created after incorporating BFI data. Correlation of specific personality characteristics vs position on the ROL was assessed for both the initial ROL and the reformulated ROL.

RESULTS

Thirty-four applicants were interviewed and 24 (70.6%) were ranked. Linear regression analysis identified a lower neuroticism score directly related to a higher position on the initial ROL {R = .4626, P = .023}. The reformulated ROL identified a higher conscientiousness score {R = .5331; P = .007} and a lower neuroticism score {R = -.4383; P = .032} correlated with ascending the final ROL.

CONCLUSIONS

The self-administered BFI adds objectivity to personality determination gleamed from the standard face-to-face interview. Conscientiousness and neuroticism had a significant impact on the final ROL position. Adding objective personality data appears to provide additional aid in this difficult process.

Prenatal administration of heparin-binding epidermal growth factor-like growth factor in an experimental model of necrotizing enterocolitis decreased both incidence and severity of the disease

Background

Necrotizing enterocolitis (NEC) is the leading gastrointestinal cause of death in premature infants and causes long-term disabilities. Previously, enteral heparin-binding epidermal growth factor-like growth factor (HB-EGF) administered after birth demonstrated decreased incidence and severity of NEC in a neonatal animal model of NEC. We investigated the potential prophylactic strategy of preventing NEC using prenatally administered HB-EGF.

Methods

An HB-EGF (800 µg/kg/dose) dose was injected into pregnant rats via tail vein or intraperitoneal route 2 hours prior to delivery. After cesarean section (C-section) at 21 days’ gestation, the rat pups were subjected to the NEC protocol by inducing stressors: hypoxia, hypothermia, hypertonic feeds, and orogastric gavage of lipopolysaccharide (2 mg/kg). Postnatally, pups were monitored for 96 hours and assessed for the development of clinical and postmortem histological NEC.

Results

The experimental NEC incidence in untreated, stressed rat pups was 66%. Compared with untreated pups, the maternal administration of HB-EGF correlated with a significant NEC incidence and severity decrease in rat pups. The strongest decrease was seen when HB-EGF was administered via the intraperitoneal route 2 hours prior to C-section (66% vs 31%, *p<0.05). Prenatal HB-EGF administration significantly increased pups’ survival after NEC protocol exposure, with the greatest benefit observed in the group that received HB-EGF intraperitoneally 2 hours before delivery.

Conclusions

Prenatal administration of HB-EGF decreases the incidence and severity of NEC, preserves gut barrier function and increases survival. This may represent a novel prophylactic clinical strategy for NEC offered to mothers at risk of delivering a premature infant.

Bifractal structure of chromatin in rat lymphocyte nuclei

The small-angle neutron scattering (SANS) on the rat lymphocyte nuclei demonstrates the bifractal nature of the chromatin structural organization. The scattering intensity from rat lymphocyte nuclei is described by power law Q^{-D} with fractal dimension approximately 2.3 on smaller scales and 3 on larger scales. The crossover between two fractal structures is detected at momentum transfer near 10^{-1}nm^{-1}. The use of contrast variation (D_{2}O-H_{2}O) in SANS measurements reveals clear similarity in the structural organizations of nucleic acids (NA) and proteins. Both chromatin components show bifractal behavior with logarithmic fractal structure on the large scale and volume fractal with slightly smaller than 2.5 structure on the small scale. Scattering intensities from chromatin, protein component, and NA component demonstrate an extremely extensive range of logarithmic fractal behavior (from 10^{-3} to approximately 10^{-1}nm^{-1}). We compare the fractal arrangement of rat lymphocyte nuclei with that of chicken erythrocytes and the immortal HeLa cell line. We conclude that the bifractal nature of the chromatin arrangement is inherent in the nuclei of all these cells. The details of the fractal arrangement-its range and correlation/interaction between nuclear acids and proteins are specific for different cells and is related to their functionality.

Observation of nucleic acid and protein correlation in chromatin of HeLa nuclei using small-angle neutron scattering with D_{2}O-H_{2}O contrast variation

The small-angle neutron scattering (SANS) on HeLa nuclei demonstrates the bifractal nature of the chromatin structural organization. The border line between two fractal structures is detected as a crossover point at Q_{c}≈4×10^{-2}nm^{-1} in the momentum transfer dependence Q^{-D}. The use of contrast variation (D_{2}O-H_{2}O) in SANS measurements reveals clear similarity in the large scale structural organizations of nucleic acids (NA) and proteins. Both NA and protein structures have a mass fractal arrangement with the fractal dimension of D≈2.5 at scales smaller than 150 nm down to 20 nm. Both NA and proteins show a logarithmic fractal behavior with D≈3 at scales larger than 150 nm up to 6000 nm. The combined analysis of the SANS and atomic force microscopy data allows one to conclude that chromatin and its constitutes (DNA and proteins) are characterized as soft, densely packed, logarithmic fractals on the large scale and as rigid, loosely packed, mass fractals on the smaller scale. The comparison of the partial cross sections from NA and proteins with one from chromatin as a whole demonstrates spatial correlation of two chromatin's components in the range up to 900 nm. Thus chromatin in HeLa nuclei is built as the unified structure of the NA and proteins entwined through each other. Correlation between two components is lost upon scale increases toward 6000 nm. The structural features at the large scale, probably, provide nuclei with the flexibility and chromatin-free space to build supercorrelations on the distance of 10^{3} nm resembling cycle cell activity, such as an appearance of nucleoli and a DNA replication.

Large mesenteric cyst mimicking an ovarian cyst in an 8-year-old: A case report

INTRODUCTION AND IMPORTANCE

Pediatric mesenteric cysts, rare and usually benign intra-abdominal tumors, are a difficult preoperative diagnosis due to ambiguous clinical characteristics. The final diagnosis is typically established only during surgery or histological analysis.

CASE PRESENTATION

An 8-year-old female presented with five days of worsening abdominal pain, associated with nausea, vomiting, and fever, as well as vague tenderness in the right quadrants on examination. Computed tomography imaging showed a 10.5 × 8.7 × 7 cm abdominal mass, most suspicious for a cystic mass of ovarian origin. Upon diagnostic laparoscopy, a mesenteric cyst extending to the root of the mesentery was visualized and entirely resected after conversion to an exploratory laparotomy. Histopathological examination of both the cystic fluid and specimen suggest a benign mesenteric cyst.

CLINICAL DISCUSSION

Although mesenteric cysts are noticeably rare, it is important differential to consider in pediatric patients with non-specific symptoms like abdominal pain and distention, intestinal obstruction, or a palpable abdominal mass. Notably, these cysts can be managed successfully by complete surgical resection with an excellent outcome.

CONCLUSION

This report recounts an interesting case of a large mesenteric cyst that mimicked an ovarian cyst in a pre-pubertal girl.

Thoracoscopic segmentectomy for a large previously undiagnosed CPAM presenting as a spontaneous pneumothorax: A case report

Introduction

Incidentally found congenital pulmonary airway malformations (CPAM) in older children are extremely rare and have traditionally been managed with minimally invasive versus open lobectomy of the affected lobe.

Presentation of case

In this report, we present a 11-year-old male who presented with a recurrent spontaneous pneumothorax and was found to have a large symptomatic CPAM confined to a single segment of the right lower lobe. The patient was successfully treated with thoracoscopic segmentectomy without any residual disease seen on follow up imaging.

Discussion

Minimally invasive thoracoscopic approach has many advantages over open approach including better pain control, reduced hospital length of stay, and decreased intraoperative blood loss. With increasing use of minimally invasive approaches, lung-sparing surgery has demonstrated to be a viable and an attractive option for definitive resection of CPAM, without compromising resection margins and/or future lung function.

Conclusion

This report demonstrates that minimally invasive lung-sparing surgical treatment of a large CPAM is feasible in older children.

•

Older children with CPAM can present with a spontaneous pneumothorax.

•

CPAM confined to a segment of a single lobe should be managed with segmentectomy.

•

VATS segmentectomy for CPAM in older children can be successful.

The diminishing experience in pediatric surgery for general surgery residents in the United States

PURPOSE

The Accreditation Council for Graduate Medical Education (ACGME) regulates the general surgery residency curriculum. Case volume remains a priority as recent concerns surrounding a lack of proficiency for certain surgical cases have circulated. We hypothesize that there is a significant decrease in pediatric surgery case numbers during general surgery residency despite residents meeting the minimum case requirements.

METHODS

We reviewed publicly available ACGME case reports for general surgery residency from 1999 to 2018. Cases are classified as Surgeon Chief or Surgeon Junior. Analyzed data included case classifications, number of residents, and number of residency programs. Simple linear regression analysis was performed.

RESULTS

We identified a significant decrease in total number of logged pediatric surgery cases over the past 20 years (p<0.001). Nearly 60% of cases were logged under a single category - inguinal/umbilical hernia. From the past five years, pyloric stenosis was the only other category with an average of greater than two cases logged (range 2.1-2.8).

CONCLUSION

We identified a significant decrease in total pediatric surgery case numbers during general surgery residency from 1999 to 2018. Though meeting set requirements, overall case variety was limited. With minimal number of cases required by the ACGME, graduating general surgery residents may lack proficiency in simple pediatric surgery cases.

Lipoblastomas and liposarcomas in paediatric patients: A case series

Lipoblastomas and liposarcomas are rare causes of soft tissue masses in paediatric patients. In this retrospective clinical case series we identified 11 patients from our paediatric database (10 with a lipoblastoma and one with a liposarcoma) who had attended our hospital between 1998 and 2019. The median age of patients with lipoblastoma was 29 months. All lipoblastoma cases were managed with surgical excision and histological examination. The 18-year old patient with liposarcoma presented with a metastatic and unresectable tumour that was unresponsive to chemotherapy and radiation. Our experience demonstrates the importance of differentiating the type of soft tissue mass in children.

Single site versus conventional laparoscopic appendectomy: some pain for no gain?

INTRODUCTION

The optimal laparoscopic appendectomy approach is not clear, comparing single site laparoscopic appendectomy (SILA) to conventional 3-port appendectomy (CLA). We investigated outcomes in pediatric patients comparing SILA to CLA: length of operation, length of stay, time to resumption of regular diet, follow up, rehospitalization, and cost.

METHODS

Data was collected from children 1 to 18 years with appendectomy at Loma Linda University from 2018 to 2020, operated by two surgeons. Analysis utilized two-sample T, chi-squared, and Fisher's exact tests.

RESULTS

Of 173 patients, 77 underwent SILA and 96 had CLA. There was no gender, age, or race difference between groups. Mean WBC was 17.5 × 10³/mL in SILA group, compared to 15.3 × 10³/mL in CLA group (P = 0.004). Operative time was 47.0 SILA compared to 49.5 minutes CLA (P = 0.269). Of SILA cases, 55.8% were simple appendicitis, while 53.3% of the CLA cases were simple (P = 0.857). Regular diet was resumed after 1.7 days in the SILA group, 1.1 days in CLA (P = 0.018). Length of stay was 2.9 days for SILA, 2.4 days for CLA (P = 0.144). Seven children required hospital readmission, 5 SILA and 2 CLA (P = 0.244). Five of the children who returned had intra-abdominal abscesses, of whom 4 had SILA. There was no difference in cost.

CONCLUSIONS

The operative techniques had similar outcomes and operative times. There was a trend toward more intra-abdominal abscesses in the SILA group. Further study and longer follow up is needed to determine if there is an advantage to one laparoscopic approach over another.

Antenatal Diagnosis of Retroperitoneal Cystic Mass: Fetiform Teratoma or Fetus in Fetu? A Case Report

BACKGROUND Teratoma, a tumor containing a variety of tissues, is a broad diagnosis containing mature teratoma, immature teratoma, and teratomas with malignant transformation. The tumor forms during embryological development secondary to unsuccessful migration of primordial germ cells. A specific type of mature teratoma, containing human-like features, is called a fetiform teratoma. The fetiform teratoma is often compared and confused with fetus in fetu, a reabsorbed twin. While these tumors have commonly been described in the gonads, the retroperitoneal location finding on antenatal imaging is rare. The distinction between the aforementioned subtypes is not well established, proving a challenging diagnosis prior to resection. CASE REPORT We present a case of a newborn male with a prenatal diagnosis of retroperitoneal cystic mass. Although prenatal imaging was obtained, the diagnosis remained unclear. After birth, planned surgical excision on day of life 7 showed the suprarenal mass contained contiguous intestinal elements. Histopathology examination revealed a mature cystic teratoma with multiple tissue types, including colonic, brain, respiratory, lymphatics, and nerves, reminiscent of fetiform teratoma. This case report presents an interesting example of differentiating elements straddling the diagnoses mentioned above. CONCLUSIONS This is the first reported case of fetiform teratoma diagnosed in a newborn and is especially unique for having the element of intestinal duplication within the retroperitoneal mass. The differentiating features of fetus in fetu and fetiform teratoma depend on subjective distinctions. The case provides an opportunity to discuss the differentials and management strategies.

Metastatic melanoma of the spleen without known primary

We present the case of a patient who underwent a laparoscopic splenectomy for splenomegaly associated with anemia and thrombocytopenia thought to be secondary to lymphoma and was found to have metastatic melanoma without a primary source. This is a rare entity in that the patient falls into an atypical population group with conflicting opinions about management that has been scarcely reported in the literature.

Phase behavior of ultrasoft spheres show stable bcc lattices

The phase behavior of supersoft spheres is explored using solutions of ultralow cross-linked poly(N-isopropylacrylamide)-based microgels as a model system. For these microgels, the effects of the electric charges on their surfaces can be neglected and therefore only the role of softness on the phase behavior is investigated. The samples show a liquid-to-crystal transition at higher volume fraction with respect to both hard spheres and stiffer microgels. Furthermore, stable body centered cubic (bcc) crystals are observed in addition to the expected face centered cubic (fcc) crystals. Small-angle x-ray and neutron scattering with contrast variation allow the characterization of both the microgel-to-microgel distance and the architecture of single microgels in crowded solutions. The measurements reveal that the stable bcc crystals depend on the interplay between the collapse and the interpenetration of the external shell of the ultralow cross-linked microgels.

Switch of fractal properties of DNA in chicken erythrocytes nuclei by mechanical stress

The small-angle neutron scattering (SANS) on the chicken erythrocyte nuclei demonstrates the bifractal nature of the chromatin structural organization. Use of the contrast variation (D_{2}O-H_{2}O) in SANS measurements reveals the differences in the DNA and protein arrangements inside the chromatin substance. It is the DNA that serves as a framework that constitutes the bifractal behavior showing the mass fractal properties with D=2.22 at a smaller scale and the logarithmic fractal behavior with D≈3 at a larger scale. The protein spatial organization shows the mass fractal properties with D≈2.34 throughout the whole nucleus. The borderline between two fractal levels can be significantly shifted toward smaller scales by centrifugation of the nuclei disposed on the dry substrate, since nuclei suffer from mechanical stress transforming them to a disklike shape. The height of this disk measured by atomic force microscopy (AFM) coincides closely with the fractal borderline, thus characterizing two types of the chromatin with the soft (at larger scale) and rigid (at smaller scale) properties. The combined SANS and AFM measurements demonstrate the stress induced switch of the DNA fractal properties from the rigid, but loosely packed, mass fractal to the soft, but densely packed, logarithmic fractal.

A Rare Combination of Left-Sided Gastroschisis and Omphalocele in a Full-Term Neonate: A Case Report

BACKGROUND Left-sided gastroschisis is a rare congenital birth defect characterized by herniation of intra-abdominal organs through an abdominal wall defect to the left of the umbilicus. Approximately half of the 31 cases reported in the literature describe other associated anomalies. To the best of our knowledge, it has never been reported in association with an omphalocele. CASE REPORT Here, we present the case of a female newborn, 37 weeks gestational age, born with a 3×6 cm omphalocele and a left-sided gastroschisis with herniation of the small bowel. Both of these anomalies were managed separately, with initial placement of a silo bag on the gastroschisis defect and application of topical agents to the omphalocele until complete epithelialization was achieved. The herniated bowel at the gastroschisis site was reduced with the aid of the silo by 96 hours and the fascia then closed primarily. A gastrostomy tube (G-tube) was placed at 16 weeks of age because of poor oral intake. Definitive closure of the omphalocele and removal of the gastrostomy tube was achieved at 13 months. Her subsequent follow-up visits in the clinic have been uneventful. CONCLUSIONS Our case report highlights the importance of recognizing this combination of rare conditions and directing appropriate surgical care.

Cold and distant: structural features of the nucleoprotein complex of a cold-adapted influenza A virus strain

Two influenza A nucleoprotein variants (wild-type: G102R; and mutant: G102R and E292G) were studied with regard to macro-molecular interactions in oligomeric form (24-mers). The E292G mutation has been previously shown to provide cold adaptation. Molecular dynamics simulations of these complexes and trajectory analysis showed that the most significant difference between the obtained models was distance between nucleoprotein complex strands. The isolated complexes of two ribonucleoprotein variants were characterized by transmission electron microscopy and differential scanning fluorimetry (DSF). Presence of the E292G substitution was shown by DSF to affect nucleoprotein complex melting temperature. In the filament interface peptide model, it was shown that the peptide corresponding in primary structure to the wild-type NP (SGYDFEREGYS) is prone to temperature-dependent self-association, unlike the peptide corresponding to E292G substitution (SGYDFGREGYS). It was also shown that the SGYDFEREGYS peptide is capable of interacting with a monomeric nucleoprotein (wild type); this interaction's equilibrium dissociation constant is five orders of magnitude lower than for the SGYDFGREGYS peptide. Using small-angle neutron scattering (SANS), the supramolecular structures of isolated complexes of these proteins were studied at temperatures of 15, 32, and 37 °C. SANS data show that the structures of the studied complexes at elevated temperature differ from the rod-like particle model and react differently to temperature changes. The data suggest that the mechanism behind cold adaptation with E292G is associated with a weakening of the interaction between strands of the ribonucleoprotein complex and, as a result, the appearance of inter-chain interface flexibility necessary for complex function at low temperature.Communicated by Ramaswamy H. Sarma.

A Potent Host Defense Peptide Triggers DNA Damage and Is Active against Multidrug-Resistant Gram-Negative Pathogens

Gram-negative bacteria are some of the biggest threats to public health due to a large prevalence of antibiotic resistance. The difficulty in treating bacterial infections, stemming from their double membrane structure combined with efflux pumps in the outer membrane, has resulted in a much greater need for antimicrobials with activity against these pathogens. Tunicate host defense peptide (HDP), Clavanin A, is capable of not only inhibiting Gram-negative growth but also potentiating activity in the presence of Zn(II). Here, we provide evidence that the improvements of Clavanin A activity in the presence of Zn(II) are due to its novel mechanism of action. We employed E. coli TD172 (ΔrecA::kan) and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to show in cellulae that DNA damage occurs upon treatment with Clavanin A. In vitro assays demonstrated that Zn(II) ions are required for the nuclease activity of the peptide. The quantum mechanics/molecular mechanics (QM/MM) calculations were used to investigate the mechanism of DNA damage. In the rate-determining step of the proposed mechanism, due to its Lewis acidity, the Zn(II) ion activates the scissile P-O bond of DNA and creates a hydroxyl nucleophile from a water molecule. A subsequent attack by this group to the electrophilic phosphorus cleaves the scissile phosphoester bond. Additionally, we utilized bacterial cytological profiling (BCP), circular dichroism (CD) spectroscopy in the presence of lipid vesicles, and surface plasmon resonance combined with electrical impedance spectroscopy in order to address the apparent discrepancies between our results and the previous studies regarding the mechanism of action of Clavanin A. Finally, our approach may lead to the identification of additional Clavanin A like HDPs and promote the development of antimicrobial peptide based therapeutics.

Animal models of necrotizing enterocolitis

Background

Necrotizing enterocolitis (NEC) is one of the leading causes of death in premature infants. To determine the factors present in the disease that lead to increased morbidity and mortality, manipulation of variables that are shown to have a positive response has been tested using various animal models. Testing and manipulation of these variables are unwarranted in humans due to regulatory health standards.

Methods

The purpose of this review is to provide an update to previous summaries that determine the significance of animal models in studying the mechanisms of NEC. A large variety of animal models including rats, mice, rabbits, piglets, nonhuman primates, and quails have been described in literature. We reviewed the reported animal models of NEC and examined the pros and cons of the various models as well as the scientific question addressed.

Results

The animals used in these experiments were subject to gavage feeding, hypoxia, hypothermia, oxygen perfusion, and other methods to induce the disease state. Each of these models has been utilized to show the effects of NEC on the premature, undeveloped gut in animals to find a correlation to the disease state present in humans. We found specific advantages and disadvantages for each model.

Conclusions

Recent advances in our understanding of NEC and the ongoing therapeutic strategy developments underscore the importance of animal models for this disease.

Gastrosplenic Fistula without Malignancy Management in a 16-Year-Old Boy

Gastrosplenic fistula is a very rare entity, most commonly occurring as a distinctive complication of splenic or gastric malignancies, most notably diffuse large B cell lymphoma (DLBCL). Benign gastric ulcer, splenic abscess, and Crohn's disease have also been reported as possible causes. We report a nonmalignant case of 16-year–old male with a gastrosplenic fistula of unclear etiology. The fistulous tract was confirmed by an upper endoscopy and an upper gastrointestinal series. Subsequently, it was surgically managed with a subtotal gastrectomy with “Roux-en-Y” reconstruction and a feeding jejunostomy.

Isolated Thoracoschisis with Rib Agenesis and Liver Herniation: A Case Report

Patient: Male, 30-day-old

Final Diagnosis: Thoracoschisis

Symptoms: Respiratory distress

Medication: —

Clinical Procedure: —

Specialty: Surgery

Direct Assessment of Tube Dilation in Entangled Polymers

A key ingredient within theories focusing on the rheology of entangled polymers is the way how the topological constraints of an entangled chain are lifted by unconstrained segments, i.e., how the constraining tube is dilated. This important question has been addressed by directly measuring the tube diameter d at the scale of the tube by neutron spin echo spectroscopy. The tube diameter d and plateau modulus G_{N}^{0} of highly entangled polyethylene oxide (PEO) chains of volume fraction c that are diluted by low molecular PEO show a concentration dependence d∝c^{a/2} and G_{N}^{0}∝c^{1+a} with an exponent a close to 4/3. This result allows the clear discrimination between different theoretical models that predict 4/3 or other values between 1 and 2 and provides an important ingredient to tube model theories.

All-DNA System Close to the Percolation Threshold

We characterize via small-angle neutron scattering the structural properties of a mixture of all-DNA particles with functionalities 4 (A) and 2 (B) constrained by design to reside close to the percolation threshold. DNA base sequences are selected such that A particles can only bind with B ones and that at the studied temperature (10 °C) all AB bonds are formed and long-lived, originating highly polydisperse persistent equilibrium clusters. The concentration dependence of the scattered intensity and its wavevector dependence is exploited to determine the fractal dimension and the size distribution of the clusters, which are found to be consistent with the critical exponents of the 3-D percolation universality class. The value of DNA nanoparticles as nanometric patchy colloids with well-defined functionality, bonding selectivity, and exquisite control of the interaction strength is demonstrated.