Development of the foregut and the formation of the trachea and esophagus in rat embryos. A symphony of confusion.

Introduction: During embryonic development, the trachea emerges from an area of the foregut, which is often referred to as "anterior" or "common" foregut tube or simply foregut. To explain this process of differentiation, four competing models exist to date. The outgrowth and watershed models propose a foregut that remains constant in length. In the outgrowth model, the trachea buds off and elongates from the foregut, while in the watershed model, a mesenchymal wedge splits the growing foregut into the trachea and esophagus. In contrast, the septation model proposes a cranial splitting and thus a shortening of the "common" foregut tube into the trachea and esophagus by an emerging septum. Finally, the splitting and extension model describes an interaction of cranial splitting of the foregut and simultaneous caudal tracheal and esophageal growth. Methods: Here we examine the development of the undifferentiated foregut by micro computed tomography, which allows precise measurements. Results: Our results show that this area of the foregut transforms into the larynx, a process, which is independent from tracheal and esophageal development. Discussion: These observations are only consistent with the outgrowth model.

Pediculated Accessory Liver Lobe with Gallbladder in a Preterm with Umbilical Cord Hernia.

(1) Background: Accessory liver lobes are a rare finding and only a few case reports of accessory liver lobes in abdominal wall defects have been reported so far. In the case of a congenital wall defect including liver parenchyma, there is still an ongoing debate on the definition of the abdominal wall defect and best care practice. Even though congenital abdominal wall defects are frequently diagnosed in prenatal screenings, controversy on the underlying etiology, embryology and underlying anatomy remains. Prenatal distinction between omphalocele and hernia into the cord cannot always be obtained; however, due to its clinical relevance for postnatal management and counseling of parents, accurate diagnosis is essential. (2) Case Presentation: We describe the uncommon postnatal finding of a pediculated accessory liver lobe with gallbladder in a preterm with umbilical cord hernia, which was prenatally diagnosed as omphalocele. Postnatal examination revealed an amniotic sac with a diameter of six and a small abdominal wall defect of three centimeters in diameter. Postnatal management included resection of the accessory liver lobe and gallbladder and closure of the defect. (3) Results and (4) Conclusions: Throughout the literature, the distinction between umbilical cord hernia and omphalocele has been variable. This has led to confusion and difficulties regarding postnatal treatment options. In order to achieve an accurate prenatal and/or postnatal diagnosis, the morphological differences and clinical manifestation of umbilical cord hernia and omphalocele need to be assessed. Further embryological studies are warranted to understand the underlying embryological pathology of omphalocele and umbilical cord hernia and offer appropriate treatment. In consideration of possibly severe complications in the case of the torsion of a pedunculated accessory liver lobe, we strongly recommend primary removal once pre- or intraoperative identification has been made.

Minimally Invasive Approaches for Traumatic Rupture of the Pancreas in Children-A Case Series.

Pancreatic trauma in children is rare; therefore, both scientific knowledge and clinical experience regarding its management are limited. Abdominal sonography and subsequent computed tomography (CT) imaging are the diagnostic mainstay after severe abdominal trauma in many pediatric trauma centers. However, the diagnosis of pancreatic injury is missed on the initial imaging in approximately one third of cases, with even higher numbers in young children. While conservative treatment is preferred in low-grade injuries, surgical interventions may be indicated in more severe injuries. We present a case series including four patients with high-grade pancreatic injury. Two patients were treated surgically with open laparotomy and primary suture of the head of the pancreas and pancreatico-enterostomy, one patient underwent endoscopic stenting of the pancreatic duct and one received conservative management including observation and secondary endoscopic treatment. We want to emphasize the fact that using a minimally invasive approach can be a feasible option in high-grade pancreatic injury in selected cases. Therefore, we advocate the necessity of fully staffed and equipped high-level pediatric trauma centers.

Thoracoscopic Guided Pericostal Sutures as a Solid Fixation for Primary Closure of Congenital Diaphragmatic Hernias.

Purpose: To describe a minimally invasive technique with primary closure and strong suture connection that is feasible in cases of larger, most common type B defects of congenital diaphragmatic hernia (CDH). Background: The thoracoscopic approach (TA) is a favorable technique for the repair of CDH and is still evolving globally. A common issue is finding the optimal suture technique for secure closure in order to prevent recurrences. Whether a defect can be closed only by sutures or by using a patch depends on the size of CDH, the presence of a muscular rim along the inner thoracic surface and finally on the surgeon's experience. From a geometrical point of view, the challenge is to transform the circular defect into a line, without tension, with a strong compound and preferably without additional material. To address this, we apply a setting of the sutures in a "T-shape" and a way to lead the sutures around the rib bones in order to increase stability. This method allows for the primary closure of CDHs and also applies to larger defects. Cases: We present seven newborns with posterolateral CDH on the left side. The defects were solely repaired by TA and by the suturing technique described in detail.

Transanal Endoscopic-Assisted Pull-Through Colectomy for Children with High Intestinal Aganglionosis.

Intestinal aganglionosis in children is a common cause of neonatal and infantile obstruction or ileus. Diagnosis is based on a histologically proven absence of enteric ganglion cells in deep biopsies of the gut wall. Therapeutic goal is a one-stage repair with a resection of the affected segment. The endorectal pull-through (ERP) can be performed entirely transanally in a lot of the cases. In patients with difficult preparation or a high aganglionosis ERP often needs to be assisted by laparoscopy or laparotomy. We present two cases with a technical modification performing a totally transanal pull-through colectomy without any trocars other than an umbilical camera trocar. The procedure starts with a classical endorectal technique. Usually, the transanal preparation is limited by reaching the colon descendens. A camera trocar is inserted and under laparoscopic vision the preparation is completed placing the instruments directly via the opened anus. After reaching the healthy colon segment, the pull-through is completed transanally. One of the main advantages of ERP is the sparing dissection. Our modification combines advantages of laparoscopy and ERP. The umbilical camera allows an excellent view while the instruments for dissection are used like with ERP without any further trocar or traction of the anal sphincter. The dispensation of any transanal trocar allows a higher grade of freedom in preparation and possibly a smaller trauma on the distal anal channel.

Tissue ACE phenotyping in lung cancer.

BACKGROUND: Pulmonary vascular endothelium is the main metabolic site for Angiotensin I-Converting Enzyme (ACE)-mediated degradation of several biologically-active peptides (angiotensin I, bradykinin, hemo-regulatory peptide Ac-SDKP). Primary lung cancer growth and lung cancer metastases decrease lung vascularity reflected by dramatic decreases in both lung and serum ACE activity. We performed precise ACE phenotyping in tissues from subjects with lung cancer. METHODOLOGY: ACE phenotyping included: 1) ACE immunohistochemistry with specific and well-characterized monoclonal antibodies (mAbs) to ACE; 2) ACE activity measurement with two ACE substrates (HHL, ZPHL); 3) calculation of ACE substrates hydrolysis ratio (ZPHL/HHL ratio); 4) the pattern of mAbs binding to 17 different ACE epitopes to detect changes in ACE conformation induced by tumor growth (conformational ACE fingerprint). RESULTS: ACE immunostaining was dramatically decreased in lung cancer tissues confirmed by a 3-fold decrease in ACE activity. The conformational fingerprint of ACE from tumor lung tissues differed from normal lung (6/17 mAbs) and reflected primarily higher ACE sialylation. The increase in ZPHL/HHL ratio in lung cancer tissues was consistent with greater conformational changes of ACE. Limited analysis of the conformational ACE fingerprint in normal lung tissue and lung cancer tissue form the same patient suggested a remote effect of tumor tissue on ACE conformation and/or on "field cancerization" in a morphologically-normal lung tissues. CONCLUSIONS/SIGNIFICANCE: Local conformation of ACE is significantly altered in tumor lung tissues and may be detected by conformational fingerprinting of human ACE.

ACE phenotyping in Gaucher disease.

BACKGROUND: Gaucher disease is characterized by the activation of splenic and hepatic macrophages, accompanied by dramatically increased levels of angiotensin-converting enzyme (ACE). To evaluate the source of the elevated blood ACE, we performed complete ACE phenotyping using blood, spleen and liver samples from patients with Gaucher disease and controls. METHODS: ACE phenotyping included 1) immunohistochemical staining for ACE; 2) measuring ACE activity with two substrates (HHL and ZPHL); 3) calculating the ratio of the rates of substrate hydrolysis (ZPHL/HHL ratio); 4) assessing the conformational fingerprint of ACE by evaluating the pattern of binding of monoclonal antibodies to 16 different ACE epitopes. RESULTS: We show that in patients with Gaucher disease, the dramatically increased levels of ACE originate from activated splenic and/or hepatic macrophages (Gaucher cells), and that both its conformational fingerprint and kinetic characteristics (ZPHL/HHL ratio) differ from controls and from patients with sarcoid granulomas. Furthermore, normal spleen was found to produce high levels of endogenous ACE inhibitors and a novel, tightly-bound 10-30 kDa ACE effector which is deficient in Gaucher spleen. CONCLUSIONS: The conformation of ACE is tissue-specific. In Gaucher disease, ACE produced by activated splenic macrophages differs from that in hepatic macrophages, as well as from macrophages and dendritic cells in sarcoid granulomas. The observed differences are likely due to altered ACE glycosylation or sialylation in these diseased organs. The conformational differences in ACE may serve as a specific biomarker for Gaucher disease.

Sacrococcygeal Teratoma Presenting with Vaginal Discharge and Polyp in an Infant.

BACKGROUND: Sacrococcygeal teratoma accounts for the most common solid tumor in neonates. Because of improved technology, 50%-70% of cases can be diagnosed antenatally during routine ultrasound screenings. If not diagnosed antenatally, clinical findings at birth are distinct in most cases including a palpable or visible mass. CASE: We report an unusual case of a 1-year-old girl who presented with persistent vaginal discharge leading to diagnosis of a mucosal polypoid lesion of the vagina, ultimately revealing a hidden sacrococcygeal teratoma. SUMMARY AND CONCLUSION: We suggest thorough investigation of all infants who present with purulent discharge and recurrent vaginal mass; sacrococcygeal teratoma should routinely be considered as a differential diagnosis.

Laparoscopic Management of Autoamputated Ovary in Newborns: A Report of 2 Cases.

Intrauterine autoamputation of the ovary is an extremely rare diagnosis in the pediatric population. The current literature is limited to contradictory recommendations, while a standard management protocol for autoamputated adnexa secondary to intrauterine ovarian torsion is yet to be established. We report 2 cases of auto-amputation of the ovary, leading to a free-floating intra-abdominal cyst in the newborn. Laparoscopic management was successful in both cases.

Regenerative capacity of the enteric nervous system: is immaturity defining the point of no return?

BACKGROUND: Intestinal obstruction in newborns is associated with intestinal motility disorders after surgery. Alterations in the enteric nervous system (ENS) might cause abnormal peristalsis, which may then result in intestinal motility disorders. We aimed to quantify alterations in the myenteric plexus after a ligation and to test if these alterations were reversible. METHODS: Small intestines of chicken embryos were ligated in ovo at embryonic day (ED) 11 for either 4 d (ED 11-15) or 8 d (ED 11-19). Both treated groups and control group were sacrificed and intestinal segments examined by means of both light and electron microscopy. RESULTS: The number of proximal myenteric ganglia increased (ED 19, 30.7 ± 3.16 versus 23.1 ± 2.03; P < 0.001) in the 8-d ligature group but had values similar to the control group in the 4-d ligature group. The size distribution was skewed toward small ganglia in the 8-d ligature group (ED 19, 83.71 ± 11.60% versus 3.88 ± 4.74% in the control group; P < 0.001) but comparable with the control group in the 4-d ligature group. Subcellular alterations in the 4-d ligature group were reversible. CONCLUSIONS: The pathologic alterations in the ENS were fully reversible in the 4-d ligature group. This reversibility might be linked to the degree of immaturity of the ENS.

Successful Treatment of Persistent Pain After Pectus Excavatum Repair Using Paravertebral Nerve Radiofrequency Thermoablation.

We present a case of a 25-year-old male patient suffering from severe prolonged pain after uneventful pectus excavatum repair that could be treated successfully by paravertebral nerve radiofrequency thermoablation. The patient was scheduled for a minimally invasive Nuss pectus excavatum repair. Surgical correction was performed under general anesthesia in combination with a thoracic peridural catheter. The immediate postoperative course was uneventful; however, the patient developed severe prolonged bilateral chest wall pain across segments T8 and T9. After failure of conservative treatment options, a specialized interventional anesthesiologist performed paravertebral nerve radiofrequency thermoablation of segment T9 bilaterally, after which the patient was pain free until scheduled removal of the pectus bar 3 years after placement.

Quadruple ESIN (Elastic Stable Intramedullary Nailing): Modified Treatment in Pediatric Distal Tibial Fractures.

PURPOSE: Nailing of the tibial shaft with 2 Prevot nails is the gold standard for tibial shaft fractures in children. This technical report aims to show a simple way to stabilize pediatric distal tibial fractures without changing of the operation method. METHODS: A retrospective chart review of all distal tibial fractures treated with the modified elastic stable intramedullary nailing (ESIN) method during a 6-year period was conducted. The modified ESIN technique hardly differs from the classic method, other than the addition of 2 other Prevot nails inserted using the same entry point. RESULTS: Eight children were treated with the modified ESIN. The mean operation duration was 57 minutes (range, 33 to 88 min). In all cases 2 to 4 mm titanium nails were used. None of our patients required a postoperative cast.Within an average of 14.5 days all of the patients could fully bear their weight (2 to 30 d) and full range of motion was reached. CONCLUSIONS: The modified ESIN technique achieves good results regarding stability and early weight-bearing. Therefore, this technique could be applied in unstable distal tibial fractures. Nevertheless, a prospective and biomechanical study is needed to verify our experience. LEVEL OF EVIDENCE: Level IV-therapeutic studies.

Reversible small bowel obstruction in the chicken foetus.

BACKGROUND: Ligation of the embryonic gut is an established technique to induce intestinal obstruction and subsequently intestinal atresia in chicken embryos. In this study, we modified this established chicken model of prenatal intestinal obstruction to describe (1) the kinetics of morphological changes, (2) to test if removal of the ligature in ovo is possible in later embryonic development and (3) to describe morphological adaptations following removal of the ligature. MATERIALS AND METHODS: On embryonic day (ED) 11, small intestines of chick embryos were ligated micro surgically in ovo. In Group 1 (n = 80) gut was harvested proximal and distal to the ligation on ED 12-19. In Group 2 (n = 20) the induced obstruction was released on day 15 and gut was harvested on ED 16-19. Acetyl choline esterase staining was used as to assess resulting morphological changes. RESULTS: A marked intestinal dilatation of the proximal segment can be seen 4 days after the operation (ED 15). The dilatation increased in severity until ED 19 and intestinal atresia could be observed after ED 16. In the dilated proximal segments, signs of disturbed enteric nervous system morphology were obvious. In contrast to this, release of the obstruction on ED 15 in Group 2 resulted in almost normal gut morphology at ED 19. CONCLUSION: Our model not only allows the description of morphological changes caused by an induced obstruction on ED 11 but also-more important - of morphological signs of adaptation following the release of the obstruction on ED 15.

Age-related gene expression analysis in enteric ganglia of human colon after laser microdissection.

The enteric nervous system (ENS) poses the intrinsic innervation of the gastrointestinal tract and plays a critical role for all stages of postnatal life. There is increasing scientific and clinical interest in acquired or age-related gastrointestinal dysfunctions that can be manifested in diseases such as gut constipation or fecal incontinence. In this study, we sought to analyze age-dependent changes in the gene expression profile of the human ENS, particularly in the myenteric plexus. Therefore, we used the laser microdissection technique which has been proven as a feasible tool to analyze distinct cell populations within heterogeneously composed tissues. Full biopsy gut samples were prepared from children (4-12 months), middle aged (48-58 years) and aged donors (70-95 years). Cryosections were histologically stained with H&E, the ganglia of the myenteric plexus identified and RNA isolated using laser microdissection technique. Quantitative PCR was performed for selected neural genes, neurotransmitters and receptors. Data were confirmed on protein level using NADPH-diaphorase staining and immunohistochemistry. As result, we demonstrate age-associated alterations in site-specific gene expression pattern of the ENS. Thus, in the adult and aged distal parts of the colon a marked decrease in relative gene expression of neural key genes like NGFR, RET, NOS1 and a concurrent increase of CHAT were observed. Further, we detected notable regional differences of RET, CHAT, TH, and S100B comparing gene expression in aged proximal and distal colon. Interestingly, markers indicating cellular senescence or oxidative stress (SNCA, CASP3, CAT, SOD2, and TERT) were largely unchanged within the ENS. For the first time, our study also describes the age-dependent expression pattern of all major sodium channels within the ENS. Our results are in line with previous studies showing spatio-temporal differences within the mammalian ENS.

In vivo transplantation of neurosphere-like bodies derived from the human postnatal and adult enteric nervous system: a pilot study.

Recent advances in the in vitro characterization of human adult enteric neural progenitor cells have opened new possibilities for cell-based therapies in gastrointestinal motility disorders. However, whether these cells are able to integrate within an in vivo gut environment is still unclear. In this study, we transplanted neural progenitor-containing neurosphere-like bodies (NLBs) in a mouse model of hypoganglionosis and analyzed cellular integration of NLB-derived cell types and functional improvement. NLBs were propagated from postnatal and adult human gut tissues. Cells were characterized by immunohistochemistry, quantitative PCR and subtelomere fluorescence in situ hybridization (FISH). For in vivo evaluation, the plexus of murine colon was damaged by the application of cationic surfactant benzalkonium chloride which was followed by the transplantation of NLBs in a fibrin matrix. After 4 weeks, grafted human cells were visualized by combined in situ hybridization (Alu) and immunohistochemistry (PGP9.5, GFAP, SMA). In addition, we determined nitric oxide synthase (NOS)-positive neurons and measured hypertrophic effects in the ENS and musculature. Contractility of treated guts was assessed in organ bath after electrical field stimulation. NLBs could be reproducibly generated without any signs of chromosomal alterations using subtelomere FISH. NLB-derived cells integrated within the host tissue and showed expected differentiated phenotypes i.e. enteric neurons, glia and smooth muscle-like cells following in vivo transplantation. Our data suggest biological effects of the transplanted NLB cells on tissue contractility, although robust statistical results could not be obtained due to the small sample size. Further, it is unclear, which of the NLB cell types including neural progenitors have direct restoring effects or, alternatively may act via 'bystander' mechanisms in vivo. Our findings provide further evidence that NLB transplantation can be considered as feasible tool to improve ENS function in a variety of gastrointestinal disorders.

Immunotargeting of the pulmonary endothelium via angiotensin-converting-enzyme in isolated ventilated and perfused human lung.

Vascular immunotargeting of catalase via angiotensin-converting-enzyme (ACE) attenuated lung ischemia reperfusion injury in the rat. As this might be a promising modality for extension of the viability of human lung grafts for transplantation we tested the hypothesis whether anti-ACE antibodies are suitable for human lung protection within the model of isolated perfused and ventilated human lung resections. Right after surgery for lung cancer, human lung specimens were isolated, ventilated and perfused under physiological conditions with 500 µg of either mouse monoclonal antibodies (mAb) to human ACE (9B9, I2H5, 3G8) or non-immune mouse IgG (as a negative control) followed by wash-out perfusion. Perfusion pressure, pH and lung weight gain were measured before and during perfusion. After mAb perfusion and wash-out perfusion period lung tissue was tested for the uptake of mAbs by immunohistochemistry and by enzyme-capture technique. Furthermore, antibody concentration and ACE shedding were measured within the perfusate. We found that ACE activity in tumor and normal lung tissue did not differ between the groups perfused with different mAbs. However, ACE activity in normal lung tissue (17.0 ± 6.0 U/g) was significantly higher compared to tumor tissue (6.0 ± 3.0; p < 0.01). Absolute retaining of mAbs was with 1.3 ± 1.1% of injected dose per gram of tissue in normal lung tissue, 0.7 ± 0.7% of injected dose per gram of tumor tissue and was significantly higher compared to non-immune mouse IgG (0.1 ± 0.1%/g; p < 0.01). Anti-ACE mAbs concentration in the perfusate dropped significantly to 47 ± 11% (p < 0.001) at 40 min of perfusion. No significant difference between different anti-ACE mAbs in the depletion from perfusate has been observed. mAb 9B9 showed the most intense immunostaining (i.e., most significant lung uptake) after each experiment in normal and tumor lung tissue compared to mAbs i2H5 and 3G8 (p < 0.01). These results validate the possibility of immunotargeting of pulmonary endothelium in the human lung tissue by anti-ACE mAbs under in vivo conditions. Furthermore, the model might be useful to investigate targeted therapies in lung cancer without side effects for the patient.

Changes of smooth muscle contractile filaments in small bowel atresia.

AIM: To investigate morphological changes of intestinal smooth muscle contractile fibres in small bowel atresia patients. METHODS: Resected small bowel specimens from small bowel atresia patients (n = 12) were divided into three sections (proximal, atretic and distal). Standard histology hematoxylin-eosin staining and enzyme immunohistochemistry was performed to visualize smooth muscle contractile markers α-smooth muscle actin (SMA) and desmin using conventional paraffin sections of the proximal and distal bowel. Small bowel from age-matched patients (n = 2) undergoing Meckel's diverticulum resection served as controls. RESULTS: The smooth muscle coat in the proximal bowel of small bowel atresia patients was thickened compared with control tissue, but the distal bowel was unchanged. Expression of smooth muscle contractile fibres SMA and desmin within the proximal bowel was slightly reduced compared with the distal bowel and control tissue. There were no major differences in the architecture of the smooth muscle within the proximal bowel and the distal bowel. The proximal and distal bowel in small bowel atresia patients revealed only minimal differences regarding smooth muscle morphology and the presence of smooth muscle contractile filament markers. CONCLUSION: Changes in smooth muscle contractile filaments do not appear to play a major role in postoperative motility disorders in small bowel atresia.