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Purpose: Congenital diaphragmatic hernia (CDH) is characterized by a developmental defect in the diaphragm, pulmonary hypoplasia and pulmonary hypertension. NPAS3 is a PAS domain transcription factor regulating Drosophila tracheogenesis. NPAS3 null mice develop pulmonary hypoplasia in utero and die after birth due to respiratory failure. We aimed to evaluate NPAS3 expression during normal and abnormal lung development due to CDH., Methods: CDH was induced by administering 100 mg/ml nitrofen to time-pregnant dams on embryonic day (E) 9 of gestation. Lungs were isolated on E15, E18 and E21 and NPAS3 localization was determined by immunohistochemistry and quantified using Western blotting., Results: We found that only E21 hypoplastic CDH lungs have reduced expression of NPAS3 in the terminal saccules. Western blotting confirmed the down-regulation of NPAS3 protein in the nitrofen-induced hypoplastic lungs., Conclusions: We demonstrate for the first time that nitrofen-induced hypoplastic CDH lungs have reduced NPAS3 expression in the terminal saccules during the later stages of abnormal lung development. Our findings suggest that NPAS3 is associated with pulmonary hypoplasia in CDH.

MicroRNAs (miRNAs) are short endogenous noncoding RNA molecules (∼ 22 nucleotides) that can regulate gene expression at the post-transcription level. Research interest in the role of miRNAs in lung biology is emerging. MiRNAs have been implicated in a range of processes such as development, homeostasis, and inflammatory diseases in lung tissues and are capable of inducing differentiation, morphogenesis, and apoptosis. In recent years, several studies have reported that miRNAs are differentially regulated in lung development and lung diseases in response to epigenetic changes, providing new insights for their versatile role in various physiological and pathological processes in the lung. In this review, we discuss the contribution of miRNAs to lung development and diseases and possible future implications in the field of lung biology.

Background: Social media can be particularly useful for patients or families affected by rare conditions by allowing individuals to form online communities across the world., Objective: Our aim in this study was to conduct a descriptive and quantitative analysis of the use of a social media community for Hirschsprung's Disease (HD)., Methods: In July 2011, a mother of a child with HD launched the "Shit Happens" campaign. The campaign uses social media (blogs, Twitter, and Facebook) to engage other families affected by HD. Internet analytics including Google Analytics and Facebook Insights were used to evaluate the reach and responsiveness of this campaign., Results: On the day the HD campaign was launched, 387 people viewed the blog "Roo's Journey". Blog views have now exceeded 5400 views from 37 countries. The Facebook page extends to 46 countries, has an average post reach of 298 users, 1414 "likes", and an overall reach of 131,032 users. The campaign has 135 Twitter followers and 344 tweets at the time of writing. The most common question posted on the Facebook page is related to treatment for extreme diaper rash. Responsiveness assessment demonstrated that within 2 hours of posting, a question could receive 143 views and 20 responses, increasing to 30 responses after 5 hours., Conclusions: Social media networks are well suited to discussion, support, and advocacy for health-related conditions and can be especially important in connecting families affected by rare conditions. The HD campaign demonstrates the reach and responsiveness of a community that primarily relies on social media to connect families affected by HD. Although responsive, this community is currently lacking consistent access to evidence-based guidance for their common concerns. We will explore innovative consumer-researcher partnerships to offer a solution in future research.

The aim of this study was to characterize the evolution of lung function and -structure in elastase-induced emphysema in adult mice and the effect of mesenchymal stromal cell (MSC) administration on these parameters. Adult mice were treated with intratracheal (4.8 units/100 g bodyweight) elastase to induce emphysema. MSCs were administered intratracheally or intravenously, before or after elastase injection. Lung function measurements, histological and morphometric analysis of lung tissue were performed at 3 weeks, 5 and 10 months after elastase and at 19, 20 and 21 days following MSC administration. Elastase-treated mice showed increased dynamic compliance and total lung capacity, and reduced tissue-specific elastance and forced expiratory flows at 3 weeks after elastase, which persisted during 10 months follow-up. Histology showed heterogeneous alveolar destruction which also persisted during long-term follow-up. Jugular vein injection of MSCs before elastase inhibited deterioration of lung function but had no effects on histology. Intratracheal MSC treatment did not modify lung function or histology. In conclusion, elastase-treated mice displayed persistent characteristics of pulmonary emphysema. Jugular vein injection of MSCs prior to elastase reduced deterioration of lung function. Intratracheal MSC treatment had no effect on lung function or histology.

As minimally invasive surgery progresses, there have been attempts to modify the technique to minimize both the number and visibility of incisions. These newer techniques are known by multiple acronyms, including single incision laparoscopic surgery (SILS). The SILS technique has gained popularity in the United States, particularly owing to its perceived improved cosmesis. The SILS technique has been primarily used in adults, and the number of pediatric publications on the topic is underwhelming. We have begun to evaluate SILS at our centre to determine its applicability in both a Canadian and pediatric practice, and this commentary discusses our initial application of the procedure.

Introduction: Considerable variability exists in the diagnostic approach to acute appendicitis (in children), affecting both quality and costs of care. Interestingly, an international evaluation of what is commonly practiced today has not been performed. We aimed to document current practice patterns in the diagnosis of appendicitis in children and to determine whether a consensus exists in the workup of these patients among Canadian, Dutch, and Saudi Arabian pediatric surgeons., Methods: We performed a cross-sectional survey using a pre-designed, self-administered, 14-item survey. We sent the survey to participants via electronic mail., Results: In total, 83 responses were received and analyzed, yielding a response rate of 42%. The majority of respondents practiced at pediatric surgery centers with over 50 beds (58% of Canadian surgeons, 81% of Dutch surgeons, 93% of Saudi Arabian surgeons). The majority of Dutch surgeons had a preference for physical examination and radiological imaging as opposed to Canadian and Saudi Arabian surgeons who favored history and physical examination. Interestingly, only one of the surgeons surveyed used an appendicitis scoring system. Regarding history and physical examination, most respondents deemed migratory abdominal pain and localized RLQ tenderness to be most suggestive of appendicitis. Ultrasound was the most preferable imaging modality in acute appendicitis across all three countries., Conclusion: This study demonstrates that international pediatric surgeons vary substantially in the diagnostic workup of patients with appendicitis. Furthermore, there is a variability between common practice and the current evidence. We recommend that pediatric surgeons develop clinical practice guidelines that are based on consensus information (expert opinion) and the best available literature., (Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.)

Nanomedicine is a rapidly emerging technology and represents an innovative field for therapy. Nanomaterials have intrinsically defined features for biomedical applications due to the high specific surface area, the amazing diversity, versatility in structure and function and the possibility of surface charge. In particular, the functionalization of targeting or stimuli-responsive unit on the surface of these materials gives them specific targeted therapeutic properties. There are many pediatric lung diseases that could potentially benefit from nanomedicine. Herein, we aim to review various drug carrier systems and release systems specifically targeting pediatric lung diseases. The injection of nanomedicine into in vivo models and their elimination will also be discussed. Finally, the potential toxicity of nanomaterials will be addressed., (© 2013 Wiley Periodicals, Inc.)

Purpose: Watercraft-associated trauma (WAT) in children has received little attention so far, despite the potentially severe and debilitating resulting injuries. The aim of this study was to evaluate all cases of major watercraft-associated trauma admitted to the Children's of Alabama during the past 10 years, identify patterns in mechanism and injury, and propose future prevention strategies., Methods: We reviewed our (prospective) database for children admitted through our trauma center after major WAT. Charts were abstracted for mechanism, epidemiologic data, injury type and injury severity scale (ISS), as well as outcome., Results: We identified 15 children (6 males, 9 females, age range 7 to 15, mean 12 ± 2 years), involved in 14 accidents. Sharp trauma was inflicted by a propeller (n=4) or a rope (n=1). Towed tubing (riding an inflatable tube while being pulled by a boat) was the most prevalent mechanism (n=6). There was a trend towards higher ISS after towed tubing (24.8 ± 12.4) compared to all other mechanisms (15.1±7.7). Mean length of stay was longer after towed tubing accidents (14.2 ± 7.2 versus 4.9 ± 3.4 days). All patients survived and eventually were discharged home. In one of the incidences, involving 2 victims of this series, the driver of the boat was intoxicated with alcohol., Conclusions: Pediatric watercraft-related accidents are infrequent, but often result in major injuries. More awareness for safety measures to prevent these injuries is warranted. Alcohol is not a major factor in pediatric watercraft-associated trauma. Tubes towed by a boat seem to be particularly dangerous, perhaps because of the rider's limited maneuverability and the fact that centrifugal force lets the tube travel well outside the wake in curves. Limiting boat speed and the use of protective gear on towed tubes when children are involved may decrease the incidence and severity of pediatric WAT., (Copyright © 2013 Elsevier Inc. All rights reserved.)

MicroRNAs (miRNAs) constitute a large group of small (∼22 nucleotides), non-coding RNA sequences that are highly conserved among animals, plants and microorganisms, suggesting that microRNAs represent a highly conserved and important regulatory mechanism. They have been demonstrated to play an important role in gene regulation. Recently, miRNAs have become a major focus of interest for research in organ development. Research focusing on the potential role of microRNAs during lung development is slowly starting to emerge. A number of miRNAs have been demonstrated to play important roles during early and late lung development. Several studies have begun to profile miRNA expression at various stages of lung development and this article provides an overview of the various miRNAs that have been implicated in lung organogenesis., (Copyright © 2012 Wiley Periodicals, Inc.)

Background: Congenital diaphragmatic hernia (CDH) can be repaired on or off extracorporeal membrane oxygenation (ECMO). In many centers, operating off ECMO is advocated to prevent bleeding complications. We aimed to compare surgery-related bleeding complications between repair on or off ECMO., Methods: All patients with CDH repair and ECMO treatment between January 1, 1995, and May 31, 2008, were retrospectively reviewed. Tranexamic acid was routinely given to all patients repaired on ECMO for 24 hours perioperatively after 2003. Extra-fluid expansion, transfusion, or relaparotomy caused by postoperative bleeding were scored as surgery-related bleeding complications and were related to the Extracorporeal Life Support Organization (ELSO) registry. We used χ(2) test and t test for statistics., Results: Demographic data and surgery-related bleeding complications in the on-ECMO group were not significantly different compared with the off-ECMO group (P = .331) in our institute. In contrast, more surgery-related bleeding complications were reported by ELSO in their on-ECMO group (P < .0001)., Conclusion: In contrast to the data from the ELSO registry, we did not observe significantly more surgery-related bleeding complications after CDH repair on ECMO. Using a specific perioperative hemostatic treatment enabled us to perform CDH repair on ECMO with a low frequency of bleeding complications, thereby taking advantage of having the physiologic benefits of ECMO available perioperatively., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Surgeons prefer to close ostomies at least 6 weeks after the primary operation because of the anticipated postoperative abdominal adhesions. Limited data support this habit. Our aim was to evaluate adhesion formation-together with an analysis of resource consumption and costs-in patients with necrotizing enterocolitis who underwent early closure (EC), compared with a group of patients who underwent late closure (LC)., Methods: Chart reviews and cost analyses were performed on all patients with necrotizing enterocolitis undergoing ostomy closure from 1997 to 2009. Operative reports were independently scored for adhesions by 2 surgeons., Results: Thirteen patients underwent EC (median, 39 days; range, 32-40), whereas 62 patients underwent LC (median, 94 days; range, 54-150). Adhesion formation in the EC group (10/13 patients, or 77%) was not significantly different (P = 1.000) from the LC group (47/59 patients, or 80%). No differences were found in the costs of hospital stay, surgical interventions, and outpatient clinic visits., Conclusions: Ostomy closure within 6 weeks of the initial procedure was not associated with more adhesions or with changes in direct medical costs. Therefore, after stabilization of the patient, ostomy closure can be considered within 6 weeks during the same admission as the initial laparotomy., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Despite modern treatments, congenital diaphragmatic hernia (CDH) remains associated with variable survival and significant morbidity. The associated pulmonary hypoplasia is a major determinant of outcome. To develop better treatments, improved comprehension of the pathogenesis of lung hypoplasia is warranted. We developed an in vitro cell recombinant model to mimic pulmonary hypoplasia and specifically to investigate epithelial-mesenchymal interactions and to decipher which tissue layer is primarily defective in nitrofen-induced CDH-associated lung hypoplasia. Epithelial cells (E) and fibroblasts (F) were isolated from E19 control ((C)) and nitrofen-induced hypoplastic rat lungs ((N)). Cells were recombined and cultured as either homotypic [(F(C))(E(C)) and (F(N))(E(N))] or heterotypic [(F(C))(E(N)) and (F(N))(E(C))] recombinants. Recombinants containing F(N) fibroblasts had a thickened fibroblast tissue layer and there were fewer organized alveolar-like epithelial structures compared with those in control (F(C))(E(C)) recombinants. These F(N) recombinants exhibited a decrease in terminal deoxynucleotidyl transferase dUTP nick end labeling and cleaved caspase-3 positive cells. Cell proliferation was arrested in recombinants containing F(N) fibroblasts, which also exhibited increased p27(Kip1) and p57(Kip2) expression. In conclusion, fibroblasts, and not epithelial cells, appear to be the defective cell type in nitrofen-induced hypoplastic lungs due to a decreased ability to undergo apoptosis and maintain overall proliferation. This may explain the characteristic pulmonary interstitial thickening and hypoplasia observed in both nitrofen-induced hypoplastic lungs as well as human hypoplastic CDH lungs., (Copyright © 2012 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

A single-incision pediatric endosurgery (SIPES) has not been typically used for operations in premature infants yet. We report a case of a 3-month-old 25-week premature infant who underwent SIPES-assisted ileocecal resection for a stricture after medically treated necrotizing enterocolitis. The patient recovered uneventfully, and was discharged on full feeds 15 postoperatively with virtually no appreciable scar. SIPES is a reasonable alternative for NEC stricture resection in premature infants. Prematurity should not be considered a contraindication to single-incision endosurgery.

Congenital diaphragmatic hernia remains a clinical challenge for both neonatologists and pediatric surgeons. Advancements in mechanical ventilation strategies and neonatal intensive care have improved survival and transformed treatment of congenital diaphragmatic hernia from emergent surgery to early stabilization of the newborn followed by delayed repair of the diaphragmatic defect. Surgical technique has evolved and minimally invasive surgical approaches to close the diaphragmatic defect in these babies will likely improve with increasing experience. Finally, as more patients are diagnosed prenatally, attempts have been made to close the diaphragmatic defect prenatally. Unfortunately, this approach did not change the outcome of affected babies. Recently, progress has been made with prenatal tracheal plugging to improve prenatal lung development. In the near future experimental studies will start to explore new ways of treating affected babies prior to birth. This article reviews the evolution of the current treatment strategies in congenital diaphragmatic hernia and its future directions., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Background: The objective was to investigate the relationship of high gun ownership and gun death rate on children and determine predictors influencing the incidence and outcome of pediatric firearm injuries in a major pediatric level 1 trauma center., Methods: We performed a retrospective review of our trauma registry to identify hospital admissions between April 1999 and March 2010. We extracted demographic and geographic data, seasonal variation, injury type, firearm type, and outcome., Results: We identified 194 firearm injuries. The incidence did not change during the past decade. Most occurred during the second half of the year (61.4%). Mean age was 12.2 ± 4.6 years (range, 0.4-19.2 years). Unintentional shootings accounted for 100 injuries followed by assaults (n = 55) and innocent bystanders (n = 39). African American children were most often injured because of a violent cause (60.3%), whereas white children were shot unintentionally (80.1%). Powder-propelled firearms caused 82.5% of injuries. Overall, 17.5% of children required an operation, and 9.3% died., Conclusions: The overwhelming majority of children were injured after a gun went off unintentionally, whereas most African American children were shot violently. We identified certain seasonal and geographic clusters. These data can be used to target gun injury prevention programs., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background and Objectives: After introducing single-incision pediatric endosurgical (SIPES) appendectomy at our institution, we noticed an increased number of post-operative umbilical infections. This study evaluates the impact of a simple, low-cost wound vacuum dressing on the wound infection rate., Methods: Umbilical wounds after single-incision laparoscopic appendectomy were covered with standard dressing (approximating strips), or the new umbilical vacuum dressing. A wound infection was defined as an infected umbilicus requiring antibiotics, or incision and drainage. The wound infection rate was compared between both groups. Statistical analysis was performed using Fischer's exact test. Continuous variables were compared using the Student t test., Results: Included in this study were 183 children, 97 of whom were treated with the vacuum dressing. The study populations were no different in terms of age, weight, operative time, blood loss, length of stay, or proportion of acute versus perforated appendicitis. A total of 7 (3.8%) wound infections occurred, 1 in the vacuum dressing group (1%), versus 6 in the conventional dressing group (7%, P=0.038)., Conclusions: This simple, low-cost umbilical vacuum dressing decreased the wound infection rate after SIPES appendectomy, possibly by absorbing secretions from the base of the wound. It may be equally effective for other indications.

Purpose: The increased use of computed tomography (CT) to diagnose appendicitis in children has led to a concern for the possibility of increased CT-related cancer morbidity. We designed a clinical protocol for the diagnosis and treatment of appendicitis in children in an attempt to decrease the use of CT scans at our institution., Methods: Patients who had surgical consultation for suspected appendicitis were placed on the clinical protocol. Data concerning diagnosis and treatment were collected prospectively. Retrospective data from patients admitted to our institution with acute appendicitis before the clinical protocol were collected as historical controls., Results: One hundred twelve patients were diagnosed and treated by our protocol between June and November 2009. Of these, 100 patients underwent an appendectomy for acute appendicitis. They were compared with 146 patients from 2007. In-house CT use decreased from 71.2% to 51.7% (P = .01). Preoperative ultrasound use increased from 2.7% to 21% (P < .001). The negative appendectomy rate increased (6.8% vs 11%, P = .25)., Conclusions: Our findings suggest that the implementation of an evidence-based clinical protocol for the diagnosis and treatment of acute appendicitis in children may safely decrease the use of CT scans and increase the use of ultrasound., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Current methods of intraoperative tumor margin detection using palpation and visual inspection frequently result in incomplete resections, which is an important problem in surgical oncology. Therefore, real-time visualization of cancer cells is needed to increase the number of patients with a complete tumor resection. For this purpose, near-infrared fluorescence (NIRF) imaging is a promising technique. Here we describe a novel, handheld, intraoperative NIRF camera system equipped with a 690 nm laser; we validated its utility in detecting and guiding resection of cancer tissues in two syngeneic rat models. The camera system was calibrated using an activated cathepsin-sensing probe (ProSense, VisEn Medical, Woburn, MA). Fluorescence intensity was strongly correlated with increased activated-probe concentration (R2= .997). During the intraoperative experiments, a camera exposure time of 10 ms was used, which provided the optimal tumor to background ratio. Primary mammary tumors (n = 20 tumors) were successfully resected under direct fluorescence guidance. The tumor to background ratio was 2.34 using ProSense680 at 10 ms camera exposure time. The background fluorescence of abdominal organs, in particular liver and kidney, was high, thereby limiting the ability to detect peritoneal metastases with cathepsin-sensing probes in these regions. In conclusion, we demonstrated the technical performance of this new camera system and its intraoperative utility in guiding resection of tumors.

Congenital diaphragmatic hernia (CDH) is a congenital anomaly consisting of a posterolateral defect in the diaphragm also known as a Bochdalek hernia. It occurs in 1 in 2000 to 3000 newborns and is associated with a variable degree of pulmonary hypoplasia (PH) and persistent pulmonary hypertension (PPH). Despite remarkable advances in neonatal resuscitation and intensive care and the new postnatal treatment strategies, many newborns with CDH continue to have high rates of mortality and morbidity as the result of severe respiratory failure secondary to PH and PPH. The pathogenesis of CDH and associated PH and PPH is poorly understood. Herein, we aim to review diaphragm and pulmonary development and correlate this to the abnormalities found in CDH., (Copyright 2010 Elsevier Inc. All rights reserved.)

Background: Fetal lung development requires proper coordination between lung epithelial and vascular morphogenesis. A major determinant in lung vascular development is vascular endothelial growth factor (VEGF), which is regulated by hypoxia-inducible factors (HIFs). VEGF is expressed in the airway epithelium, while its receptors (VEGFRs) are expressed in the pulmonary mesenchyme. The hypoxic environment in utero is beneficial for fetal organogenesis, especially vascular development. However, little is known about the expression of HIFs and VEGFR-2 in the human fetal lung in vitro., Objectives: The purpose of this study was to investigate the effects of hypoxia on fetal lung morphology and mRNA expression of VEGF, VEGFR-2, HIF-2alpha, and HIF-3alpha., Methods: An explant culture technique was used to study the effects of normoxic and hypoxic conditions on human fetal lung., Results: The morphology remained largely unchanged in explants cultured under hypoxic or normoxic conditions. Quantitative RT-PCR showed that the mRNA expression of VEGF-A, but not VEGFR-2 is upregulated in explants cultured at 1.5% compared with 21% oxygen. We observed a nonsignificant increase in HIF-2alpha and HIF-3alpha mRNA expression in explants cultured at 1.5% oxygen. These data suggest that the mRNA expression of VEGF, and possibly HIF-2alpha and HIF-3alpha, is regulated by hypoxia in the developing human lung., Conclusion: This lung explant culture model appears to be a valuable model to unravel the molecular mechanisms of human lung development., (Copyright 2009 S. Karger AG, Basel.)

Purpose: Congenital diaphragmatic hernia (CDH) has traditionally been repaired via a laparotomy. More and more reports on thoracoscopic repair are being published. The aim of this study was to evaluate our series of thoracoscopic CDH repair and compare this group to an open repair group treated during the same period in the same institute., Patients and Methods: Between June 2006 and December 2008, 49 children with posterolateral CDH were admitted, of whom 23 (47%) were operated thoracoscopically and 23 (47%) using an open repair, depending on the discretion of the attending surgeon and the clinical condition of the patient. Three patients (6%) with CDH were not treated because of associated anomalies (twice Cornelia de Lange syndrome and once hypoplastic left heart syndrome). Six thoracoscopic operations (26%) were converted to open surgery. Nine defects (39%) were closed thoracoscopically without a patch. In 8 (35%) patients, a patch was used. We used a patch in 20 open procedures (87%)., Results: Three (33%) of the 9 thoracoscopic repairs without patch and 1 (12%) of the 8 with a patch developed a recurrence. All these recurrences were repaired thoracoscopically. The 3 recurrences from the thoracoscopic primary repair were repaired using a patch. In the open group, 3 patients (13%) developed a recurrence, of whom 2 were repaired thoracoscopically. Mean operative time was significantly longer in the thoracoscopic patch repair group (158 minutes), when compared to the open repair group (125 minutes)., Conclusion: As in open repair, it seems wise to use large patches liberally, not only to reconstruct the dome of the diaphragm but also to avoid undue tension on the repair and prevent recurrences. The thoracoscopic approach is also considered feasible in case of a recurrence from either a thoracoscopic or open repair., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

Purpose: The 70-gene prognosis signature (van't Veer et al., Nature 415(6871):530-536, 2002) may improve the selection of lymph node-negative breast cancer patients for adjuvant systemic therapy. Optimal validation of prognostic classifiers is of great importance and we therefore wished to evaluate the prognostic value of the 70-gene prognosis signature in a series of relatively recently diagnosed lymph node negative breast cancer patients., Methods: We evaluated the 70-gene prognosis signature in an independent representative series of patients with invasive breast cancer (N = 123; <55 years; pT1-2N0; diagnosed between 1996 and 1999; median follow-up 5.8 years) by classifying these patients as having a good or poor prognosis signature. In addition, we updated the follow-up of the node-negative patients of the previously published validation-series (Van de Vijver et al., N Engl J Med 347(25):1999-2009, 2002; N = 151; median follow-up 10.2 years). The prognostic value of the 70-gene prognosis signature was compared with that of four commonly used clinicopathological risk indexes. The endpoints were distant metastasis (as first event) free percentage (DMFP) and overall survival (OS)., Results: The 5-year OS was 82 +/- 5% in poor (48%) and 97 +/- 2% in good prognosis signature (52%) patients (HR 3.4; 95% CI 1.2-9.6; P = 0.021). The 5-years DMFP was 78 +/- 6% in poor and 98 +/- 2% in good prognosis signature patients (HR 5.7; 95% CI 1.6-20; P = 0.007). In the updated series (N = 151; 60% poor vs. 40% good), the 10-year OS was 51 +/- 5% and 94 +/- 3% (HR 10.7; 95% CI 3.9-30; P < 0.01), respectively. The DMFP was 50 +/- 6% in poor and 86 +/- 5% in good prognosis signature patients (HR 5.5; 95% CI 2.5-12; P < 0.01). In multivariate analysis, the prognosis signature was a strong independent prognostic factor in both series, outperforming the clinicopathological risk indexes., Conclusion: The 70-gene prognosis signature is also an independent prognostic factor in node-negative breast cancer patients for women diagnosed in recent years.

Background: Laparoscopic repair of umbilical hernias is usually based on the open underlay procedure in which the mesh is placed intra-abdominally. To prevent complications such as adhesions, bowel obstruction and fistula formation we developed a new laparoscopic approach, placing the mesh in the preperitoneal space., Methods: Our laparoscopic approach concerns a standardised procedure with introduction of three intra-abdominally placed trocars. The ventral abdominal wall is incised in a lengthwise manner approximately 5 cm from the umbilical defect, followed by development of the preperitoneal space, reposition of the umbilical peritoneal sac and placement and fixation of a Prolene mesh. The mesh is secured using transfascial Prolene sutures; the peritoneal defect is closed with a running Vicryl suture. Data on 17 patients with primary umbilical hernias laparoscopically operated on between April 2002 and March 2006 are presented., Results: The 11 men and 6 women had a mean age of 57.8 years (range 37-91 years) and a mean body mass index (BMI) of 30.6 kg/m(2) (range 23.7-37.9 kg/m(2)). Mean hernia size was 1.95 cm (range 1-3 cm), average mesh size was 110 cm(2) (range 100-150 cm(2)). Mean operating time was 85.6 min (range 60-120 min). Mean hospital stay was 2.2 days (range 1-3 days). No major complications were seen. No recurrences were observed during a mean follow-up of 36.2 months (range 13-62 months)., Conclusions: The preperitoneal laparoscopic technique for umbilical hernia repair combines the advantages of a laparoscopic, minimally invasive, approach, avoiding the potential complications related to intra-abdominal mesh position.

Background: One proposed reason for the early resection of asymptomatic congenital cystic adenomatoid malformations is the theoretical benefit of optimizing compensatory lung growth during infancy and early childhood. Our aim was to determine if early lobectomy is associated with better long-term pulmonary function than lobectomy later in childhood., Methods: A retrospective chart review of children undergoing pulmonary lobectomy for benign disease from 1990 to 2006 was performed. Those having surgery before and after 2 years of age were compared. Forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)) were used as indicators of pulmonary growth, with FVC less than 80% predicted and FEV(1) less than 80% consistent with impaired pulmonary function., Results: Of 115 patients identified, 14 had postoperative pulmonary function testing at a mean age of 10 years. Of these, 7 had lobectomy before and 7 had lobectomy after 2 years of age. There was no significant difference between groups in mean FVC (81.5 vs 83.3) or the number of children with FVC less than 80% predicted, nor was there a difference in mean FEV(1) (87.6 vs 82.9) or the number of children with FEV(1) less than 80%., Conclusions: Age at the time of lobectomy did not influence FVC or FEV(1). These preliminary data suggest that early lobectomy does not confer an advantage to the child with respect to long-term pulmonary function. A prospective study is necessary to confirm or refute these findings in a larger group of children.

Congenital diaphragmatic hernia (CDH) occurs in 1 in 3,000 newborns. Mortality and morbidity are due to the amount of pulmonary hypoplasia (PH), the response on artificial ventilation and the presence of therapy-resistant pulmonary hypertension. The pathogenesis and etiology of CDH and its associated anomalies are still largely unknown despite all research efforts over the past years. Several animal models have been proposed to study CDH. In this review we compare surgical, pharmacological and transgenic models, and discuss their strengths and limitations to study PH., (Copyright 2009 S. Karger AG, Basel.)

Aims: To describe current evidence of the frequency, contents, and involved professionals of the routine follow-up visits in patients who have received a pacemaker (PM)., Methods and Results: The multicentre FOLLOWPACE study prospectively collected data during implantation and follow-up of 1526 patients who received a PM for the first time. A total of 4914 follow-up visits were studied. Mean follow-up was 394 days with a mean of 3.2 visits per patient. At all follow-up visits, the battery condition was tested in >93%, the stimulation threshold in >91%, and sensing in >87%. The pacemaker parameters as stimulation and sensing thresholds, lead impedances, and percentages of pacing remained stable over time, but these values did depend on the lead location, lead fixation, and pulse duration. The majority of PM (re-)programming was performed during implantation and/or shortly before hospital discharge (50%). PM re-programming during follow-up was most frequently performed by the PM technician alone (95%)., Conclusion: Crucial PM parameters are regularly checked. Re-programming of PM parameters declined during the first year after PM implantation. The majority of PM checks were carried out by the PM technician, indicating the major influence of the allied professional on the quality and safety of the pacing therapy.

The perinatal changes in the pattern of expression of the thyroid hormone receptor (TR) isoforms TRalpha (1) TRalpha (2), TRbeta (1), and TRbeta (2) were investigated using in situ hybridization and immunohistochemistry, and RT-PCR and western blotting as visualization and quantification techniques respectively. In liver, lung, and kidney, TRalpha mRNA was expressed in the stromal and TRbeta mRNA in the parenchymal component of the tissues. When compared with liver, TRalpha mRNA concentrations were tenfold higher in lung, kidney, and intestine, and 100-fold higher in brain, with TRalpha (2) mRNA concentrations exceeding those of TRalpha (1) 5-to 10-fold. Tissue TRbeta (1) mRNA concentrations were similar in liver, lung, and brain, and 3- to 5-fold higher in kidney and intestine. None of the TRbeta (2) mRNA could be detected outside the pituitary. Tissue TRalpha (2) and TRbeta (1) protein levels reached adult levels at 5 days before birth, whereas TRalpha (1) protein peaked after birth. Because of the distinct time-course of thyroid hormone-binding receptors TRalpha (1) and TRbeta (1), we speculate that an initiating, TRbeta (1)-mediated signaling from the parenchyma is followed by a TRalpha (1)-mediated response in the stroma. When compared with organs with a complementary parenchymal-stromal expression pattern, organs with extensive cellular co-expression of TRalpha and TRbeta (brain and intestinal epithelium) were characterized by a very low TRalpha protein: mRNA ratio, implying a low translational efficiency of TR mRNA or a high turnover of TR protein. The data indicate that the TR-dependent regulatory cascades are controlled differently in organs with a complementary tissue expression pattern and in those with cellular co-expression of the TRalpha and TRbeta genes.

Classical tissue recombination experiments have reported that at early gestation both tracheal and distal lung epithelium have the plasticity to respond to mesenchymal signals. Herein we examined the role of epithelial-mesenchymal interactions in maintaining epithelial differentiation at late (E19-E21, term = 22 days) fetal gestation in the rat. Isolated distal lung epithelial cells were recombined with mesenchymal cells from lung, skin, and intestine, and the homotypic or heterotypic recombinant cell aggregates were cultured for up to 5 days. Recombining lung epithelial cells with mesenchyme from various sources induced a morphological pattern that was specific to the type of inducing mesenchyme. In situ analysis of surfactant protein (SP)-C, SP-B, and Clara cell secretory protein (CCSP) expression, as well as SP-C and CCSP promoter transactivation experiments, revealed that distal lung epithelium requires lung mesenchyme to maintain the alveolar, but not bronchiolar, phenotype. Incubation of lung recombinants with an anti-FGF7 antibody resulted in a partial inhibition of mesenchyme-induced SP-C promoter transactivation. Immunoreactivity for Delta and Lunatic fringe, components of the Notch pathway that regulates cell differentiation, was downregulated in the heterotypic recombinants. In contrast, Hes1 mRNA expression was increased in these recombinants. Cumulatively, these results suggest that at late fetal gestation, distal lung epithelial cells are not fully committed to a specific phenotype and still have the plasticity to respond to various signals. Their alveolar phenotype is likely maintained by Notch/Notch ligand interactions and mesenchymal factors, including FGF7.

The degree of associated pulmonary hypoplasia and persistent pulmonary hypertension are major determination factors for survival in congenital diaphragmatic hernia (CDH) patients. Glucocorticoids, thyroid hormone, and vitamin A have been shown to be involved in human lung development. To determine their therapeutic potential in hypoplastic lungs of CDH patients, the temporal and spatial expression of glucocorticoid receptor, thyroid hormone receptors, retinoic acid receptors, and retinoid X receptors were evaluated in lungs of CDH patients, hypoplastic lungs from other causes, and normal lungs. As a series of supportive experiments, the expressions of these receptors were analyzed in lungs of nitrofen-induced CDH rats. Immunohistochemistry (human and rat) and in situ hybridization (rat) demonstrated no overt difference between CDH, hypoplastic, and control lungs, either in the localization nor the timing of the first expression of all analyzed receptors. The mRNA expression of each receptor was detected in all human CDH lungs by quantitative PCR. Our results suggest that, as far as receptors are concerned, hypoplastic lungs of fetuses and newborns with CDH are potentially as responsive to glucocorticoids, thyroid hormone, and retinoic acid as the lungs of normal children.

Objectives: The differentiation of white blood cells is a worldwide-accepted method to obtain medical information. The conventional microscopic differential, however, is a laborious and expensive test with a low statistical value. Especially for band cell identification there is a wide range of variance. In this report we describe the intervariability of band cell enumeration., Methods: From a septic patient, an EDTA anti-coagulated blood sample was obtained and a smear was made and stained (May-Grünwald Giemsa). A PowerPoint presentation was made twice of 100 random cells and sent to 157 different hospital laboratories in the Netherlands for a leukocyte differential. In the first survey neutrophils were differentiated in segmented and band neutrophils whereas in the second survey no discrimination was made between segmented and band neutrophils., Results: The first survey was responded by 68% of the laboratories (756 individuals) and the second survey by 73% of the laboratories (637 individuals). The laboratory mean values of the segmented neutrophils were 42.9% (SD: 7.8, range 22-64%) and 69.9% (SD: 1.4, range 62-72%) for the first and second survey respectively. For the individual technicians the values of the segmented neutrophils were 43.9% (SD: 11.2, range 15-72%) and 70.0% (SD: 2.0, range 59-77%) for the first and second survey respectively., Conclusions: Because of the enormous variation of band cell counting we recommend to cease quantitative reporting of band cells, especially since the results only have a clinical relevance in a limited number of pathological circumstances.

Oesophageal atresia and tracheo-oesophageal fistula are relatively frequently occurring foregut malformations of which the aetiology and pathogenesis are poorly understood. Recent results of molecular genetic studies, in particular the use of single and compound mutant mice, have yielded a tremendous increase in the understanding of the molecular mechanisms involved in normal and abnormal foregut morphogenesis. In the introduction of this paper, we review the very early stages of normal and abnormal embryology of the foregut derivatives and the separation of the foregut into a ventral respiratory part and a dorsal digestive part. After that, we describe the genes that have been demonstrated to play an important role in these processes.

Objective: To determine the prognostic significance of sentinel-node biopsy in patients with malignant melanoma (unlike the United States, a sentinel-node biopsy is still not routinely performed on melanoma patients in the Netherlands, as the outcomes of prospectively randomised clinical trials are being awaited)., Design: Retrospective., Methods: Between 1996 and 2001 a sentinel-node biopsy and a re-excision of the scar of the diagnostic biopsy were performed on all melanoma patients who had a Breslow thickness > or = 1 mm or a Clark level > or = IV. At operation the sentinel node was identified with a gamma probe and patent blue. It was removed and sent for pathological investigation for the presence of melanoma cells. If the sentinel node was tumour positive, a dissection of the regional lymph-node basin was performed. Subsequently, these patients were put forward for the European Organisation for Research and Treatment of Cancer (EORTC) peginterferon alfa(2b) adjuvant treatment study., Results: A sentinel-node biopsy was performed in 61 lymphnode basins in 57 patients (18 male and 39 female; median age: 45 years (range: 9-80)). The median Breslow thickness of the melanomas was 2.2 mm (range: 0.7-13 mm). In 10 of the 61 cases histological examination of the sentinel node demonstrated tumour cells. In 2 additional cases tumour cells were demonstrated only by immunohistochemical studies or complete dissection of the node. Eight regional lymph-node basins were dissected, two of which contained additional metastases. The median follow-up was 36 months (range: 1-68). During follow-up 12 of the 57 patients were found to have metastases, in 8 of these patients the sentinel-node biopsy contained tumour cells. The negative predictive value of a tumourless sentinel node with respect to the later occurrence of distant metastases was 92%., Conclusion: The patients with a tumour-positive sentinel node had a poorer prognosis with respect to distant metastases than patients with a tumour-negative node. This is the main reason for performing sentinel-node biopsy: to predict the prognosis of the disease. Therefore sentinel-node biopsy should be incorporated into the treatment of patients with malignant melanoma.

p53 overexpression occurs in more than 50% of colorectal carcinomas, which makes it an interesting target for immunotherapy. HLA class I expression on tumor cells is required for the presentation of p53 peptides and an effective T-cell mediated-immune response to ensue. To analyze to which extent p53 and HLA-I expression in a primary tumor reflects expression in liver metastases, we investigated p53, HLA-A and HLA-B/C expression in 82 colorectal carcinomas and 143 associated liver metastases of 82 patients. We used the monoclonal antibodies DO-7 (p53), HCA2 (HLA-A) and HC-10 (HLA-B/C) on formalin-fixed, paraffin embedded tissue. The percentage of expressing cells was estimated. P53 was overexpressed in 73% of the colorectal carcinomas and 66% of liver metastases. HLA-A was expressed in 98% and 96% and HLA-B/C in 100% and 94% of colorectal cancers and liver metastases respectively. There were no significant differences between the primary tumors and the liver metastases for each marker. The concordance was also very high in those cases in which more than one metastasis was available. Discordant cases consisted of tumors in which expression of p53 or HLA-A was lost in the liver metastases, whereas it was present in only a few tumor cells in the primary tumor. The combined analysis of p53 and HLA-I expression in liver metastases demonstrated that both molecules were expressed in 63% of the cases. P53 and HLA-I were expressed in the majority of primary tumors and their associated liver metastases. This allows to select patients for p53-immunotherapy on the basis of p53 and HLA-I expression in the primary tumor.

Neonates with congenital diaphragmatic hernia (CDH) suffer from a diaphragmatic defect, lung hypoplasia, and pulmonary hypertension, with poor lung function forming the major clinical challenge. Despite prenatal diagnosis and advanced postnatal treatment strategies, the mortality rate of CDH is still high. CDH has been subject of extensive research over the past decades, but its etiology remains unknown. A major problem with CDH is the failure to predict the individual response to treatment modalities like high-frequency ventilation, inhaled nitric oxide, and extracorporeal membrane oxygenation. In this study, we tested the possibility that CDH lungs are surfactant protein deficient, which could explain the respiratory failure and difficulties in treating CDH infants. We investigated this hypothesis in the nitrofen-induced CDH rat model and assessed the cellular concentrations of surfactant protein (SP)-A, -B, and -C mRNA with a quantitative radioactive in situ hybridization technique. No differences were observed between control and CDH lungs for SP mRNA expression patterns. The cellular concentration (mean OD) of SP-A and SP-B mRNA was similar at all stages whereas the mean OD of SP-C mRNA and the volume fraction of cells (% Area) expressing SP mRNA was higher in CDH lungs at term. Immunohistochemical analysis revealed no differences between control and CDH lungs for SP protein expression. No differences in the mean OD or % Area for the SP mRNAs were found between the ipsi- and contralateral side of CDH lungs. We conclude that there is no primary deficiency of surfactant proteins in the nitrofen-induced CDH rat model.

A malignant eccrine poroma (porocarcinoma) was excised from the right groin of a 78-year-old man.

Reduced cell proliferation and increased levels of cellular glutathione (GSH) are characteristic for cells that overexpress the anti-apoptotic Bcl-2 protein. We investigated the influence of various Bcl-2 domains on both these characteristics. Rat CC531 colorectal cancer cells were stably transfected with the human bcl-2 gene (CCbcl2 cells) or with bcl-2 gene constructs missing a coding sequence for a func-tional domain, BH1 (CCDeltaBH1 cells), BH3 (CCDeltaBH3 cells), BH4 (CCDeltaBH4 cells) or the transmembrane region (CCDeltaTM cells). We measured GSH levels in exponentially and confluent growing bcl-2-transfected cell populations. The fraction of S-phase cells during exponential growth was significantly reduced in CCbcl2, CCDeltaBH1, CCDeltaBH3, and CCDeltaTM cells compared with parental CC531, neo-transfected CC531 and CCDeltaBH4 cells. GSH levels in these bcl-2 transfectants were significantly higher than in the parental line measured at 50% confluence; at 100% confluence they reached a similar level as found in parental cells. Independently from the presence of BH1, BH3 or TM domains, overexpression of Bcl-2 reduces cellular proliferation under conditions of increased GSH levels. This apparent link is lost in CCDeltaBH4 cells; these cells are not reduced in cellular proliferation and harbour significantly higher GSH levels than found in the other transfectants. Studies on the subcellular localization revealed an extremely low expression of the Bcl-2 protein lacking the N-terminal BH4 domain in nuclear fractions. Nuclear translocation of Bcl-2 requires the presence of the BH4 domain and seems prominent in reducing cellular proliferation.

Immunohistochemical detection of expression of the anti-apoptotic Bcl-2 protein is widely studied as a putative prognostic and predictive factor in various types of cancer. For that purpose, heating for 10 min by microwave (MW) up t o 100 degrees C in citrate buffer, pH 6.0, prior to immunostaining is often used to retrieve Bcl-2 antigens in archival formalin-fixed, paraffin-embedded tissue. We recently reported that Bcl-2 is not only a cytoplasmic protein, but that it is present also in interphase nuclei and that it strongly associates with mitotic chromosomes. Furthermore, we showed that binding of the monoclonal antibody (MAb) #124 with nuclear/chromosomal epitopes is diminished by formaldehyde-based fixatives and cannot be restored by MW treatment for 10 min. Here we report that prolonged MW heating or heating up to 130 degrees C in a high pressure cooker (HPC), despite improved cytoplasmic immunostaining, fails to retrieve nuclear/chromosomal Bcl-2 epitopes recognized by the MAb #124 in human tissues. In contrast, these procedures can retrieve nuclear/chromosomal Bcl-2 epitopes detected by polyclonal #15616E antibodies in rat tissues. The specificity of these epitopes was confirmed by Western blot analysis of tissues treated by MW heating or HPC.

The transcription factor GATA6 is expressed in the fetal pulmonary epithelium of the developing mouse lung and loss of function studies strongly suggested that it is required for proper branching morphogenesis and epithelial differentiation. We have further investigated the role of GATA6 in this process by utilizing a pulmonary epithelium specific promoter to maintain high levels of GATA6 protein during fetal lung development. Transgenic mice expressing Gata6 cDNA under the control of the human Surfactant Protein-C (SP-C) promoter were generated and their lungs were analyzed during fetal stages. Transgenic lungs exhibit branching defects as early as embryonic day (E) 14.5 and molecular analysis just before birth (E18.5) shows a lack of distal epithelium differentiation whereas proximal epithelium is unaffected. Electron microscopic analysis and glycogen staining confirm the lack of differentiation to mature Type II cells. Thus, elevated levels of GATA6 protein affect early lung development and in analogy to other GATA factors in other tissues, GATA6 also plays a crucial role in the terminal differentiation in this case of the distal pulmonary epithelium.

Bcl-2 and Bax belong to a family of proteins involved in apoptosis regulation and are believed to reside in the cellular cytoplasm. The authors recently reported interphase nuclear localization of both proteins after immunofluorescence staining of formaldehyde- and methanol-fixed human and rodent cell monolayers. In addition, the authors' data confirmed earlier reports on Bcl-2 immunoreactivity of mitotic chromosomes in human cells. In their experience, nuclear or mitotic staining of Bcl-2, in contrast with cytoplasmic Bcl-2 immunoreactivity, is rarely observed in formaldehyde-fixed, paraffin-embedded breast cancer specimens. Therefore, the authors wondered if nuclear and mitotic Bcl-2 immunoreactivity could be irreversibly reduced by certain fixation procedures, including formaldehyde fixation. Here the authors investigated the effects of various routinely used fixation protocols and antigen retrieval techniques on Bcl-2 and Bax immunoreactivity in monolayers of MCF-7 human breast cancer cells. Whereas nuclear and mitotic immunoreactivity for Bcl-2 was clearly present after formaldehyde and methanol fixation, it was completely absent in cells fixed in acetone, methanol, or formaldehyde alone. In addition, it was found that in particular nuclear and mitotic Bcl-2, and to a lesser extent cytoplasmic Bcl-2 immunoreactivity, decreased after prolonged formaldehyde fixation, whereas Bax immunoreactivity diminished only slightly. Heat-mediated antigen retrieval after prolonged formaldehyde fixation elevated cytoplasmic, but not nuclear and mitotic, Bcl-2 immunoreactivity.

Recent loss-of-function studies in mice show that the transcription factor GATA6 is important for visceral endoderm differentiation. It is also expressed in early bronchial epithelium and the observation that this tissue does not receive any contribution from Gata6 double mutant embryonic stem (ES) cells in chimeric mice suggests that GATA6 may play a crucial role in lung development. The aim of this study was to determine the role of GATA6 in fetal pulmonary development. We show that Gata6 mRNA is expressed predominantly in the developing pulmonary endoderm and epithelium, but at E15.5 also in the pulmonary mesenchyme. Blocking or depleting GATA6 function results in diminished branching morphogenesis both in vitro and in vivo. TTF1 expression is unaltered in chimeric lungs whereas SPC and CC10 expression are attenuated in abnormally branched areas of chimeric lungs. Chimeras generated in a ROSA26 background show that endodermal cells in these abnormally branched areas are derived from Gata6 mutant ES cells, implicating that the defect is intrinsic to the endoderm. Taken together, these data demonstrate that GATA6 is not essential for endoderm specification, but is required for normal branching morphogenesis and late epithelial cell differentiation.

Antenatal hormonal modulation of pulmonary growth has been successfully introduced in clinical practice to reduce the incidence of respiratory distress syndrome (RDS) of preterm born infants. However, a certain amount of reserve to repeat courses should be taken into account because of possible adverse effects of antenatal administration of glucocorticoids. Although in experimental animals thyroid hormones given alone were not shown to have stimulatory effects on pulmonary development, there was an apparent synergistic effect with corticosteroids. Yet, such effects have not been substantiated in clinical trials. Whereas in cases of congenital diaphragmatic hernia (CDH) in utero tracheal occlusion could stimulate fetal lung growth and modulation, the enhancement of type II cell differentiation is more likely to be achieved with antenatal exposure to hormonal therapies. However, there is still no firm scientific basis for either of these two treatment modalities in CDH. Yet, antenatal hormonal modulation is now soon to be tested in an extensive multi-center clinical trial. In this review, the current status of antenatal hormonal modulation of pulmonary growth will be described and its potential role in the treatment of CDH will be discussed.

The Bcl-2 family of proteins comprises both cell death inhibiting and cell death promoting members, generally believed to be cytoplasmic and predominantly membrane-associated. Like Bcl-2, many Bcl-2-related proteins contain a C-terminal membrane insertion domain and much research is aimed at evaluating the functional role of their localization to the outer membranes of mitochondria, the endoplasmic reticulum, and perinuclear membranes. However, confocal fluorescence microscopy of human breast cancer cells and rat colon cancer cells immunostained with commercial antibodies raised against different epitopes of the anti-apoptotic Bcl-2 and the pro-apoptotic Bax protein revealed that these proteins are not only present in the cellular cytoplasm, but also within interphase nuclei. This was confirmed by Western blot analysis of isolated nuclei. In human cells, certain epitopes of Bcl-2, but not of Bax, were also found to be associated with mitotic chromatin. Anti-estrogen treatment of human breast cancer cells or transfection with antisense bcl-2 led to a reduction in both cytoplasmic and nuclear Bcl-2. Transfection of human bcl-2 and bax into rat cells resulted in cytoplasmic and nuclear Bcl-2 and Bax. This data seems in line with increasing evidence that the role of the Bcl-2 family of proteins should be extended to activities inside the nuclear compartment.

Pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH) remains a major therapeutic problem. Moreover, the pathogenesis of pulmonary hypoplasia in case of CDH is controversial. In particular, little is known about early lung development in this anomaly. To investigate lung development separate from diaphragm development we used an in vitro modification of the 2, 4-dichlorophenyl-p-nitrophenylether (Nitrofen) animal model for CDH. This enabled us to investigate the direct effects of Nitrofen on early lung development and branching morphogenesis in an organotypic explant system without the influence of impaired diaphragm development. Epithelial cell differentiation of the lung explants was assessed using surfactant protein-C and Clara cell secretory protein-10 mRNA expression as markers. Furthermore, cell proliferation and apoptosis were investigated. Our results indicate that Nitrofen negatively influences branching morphogenesis of the lung. Initial lung anlage formation is not affected. In addition, epithelial cell differentiation and cell proliferation are attenuated in lungs exposed to Nitrofen. These data indicate that Nitrofen interferes with early lung development before and separate from (aberrant) diaphragm development. Therefore, we postulate the dual-hit hypothesis, which explains pulmonary hypoplasia in CDH by two insults, one affecting both lungs before diaphragm development and one affecting the ipsilateral lung after defective diaphragm development.

It is still generally believed that the defect in congenital diaphragmatic hernia results from failure of the so-called pleuroperitoneal canals (PPCs) to close at the end of the embryonic period (8th gestational week). Furthermore, it is assumed that gut could enter the thoracic cavity through this defect, causing compression and finally hypoplasia of the lung. However, this sequence of embryological events has never been studied, and many details even of normal diaphragmatic development are still unknown. Using scanning electron microscopy and a new animal model of congenital diaphragmatic hernia (CDH), the nitrofen rat model, the normal embryology of the diaphragm was reinvestigated and, for the first time, the crucial developmental steps of congenital diaphragmatic hernia formation were studied. The basic results were: (1) In normal development, the PPCs are never wide enough to allow herniation of gut loops. (2) The formation of the defect happens in an early embryonic period. (3) The early ingrowth of liver through the defect is of major importance for the formation of CDH. In another set of experiments, the nitrofen rat model of congenital diaphragmatic hernias was used to study the cellular mechanisms involved during epithelial and mesenchymal growth and differentiation in normal and in abnormal lungs. These results, combined with selected culture techniques (eg, branching morphogenesis and epithelio-mesenchymal interaction) probably open new ways to a better understanding of the mechanisms that finally lead to an abnormal lung in CDH.

Growth of the transplantable EMR-86 rat mammary carcinoma depends on elevated prolactin levels which are induced by oestrogenic stimulation of the pituitary. We investigated histological and cell kinetic changes during tumour regression after removal of implanted oestrogen pellets (EP), and we especially focused on the role of apoptosis. After EP removal, serum prolactin decreased to basal levels in 5 days, reaching its largest depletion during the first day. Similarly, S-phase cell fractions, assessed by bromodeoxyuridine (BrdUrd) incorporation, decreased to half the initial value during the first day and developed into a gradual decrease to basal levels thereafter. Within 10 days, tumour volumes were reduced to 20% without striking changes in tissue architecture. To quantify apoptosis, we applied a method that stains DNA breaks in tissue sections and subsequently measured the stained area by automated image cytometry. This procedure was necessary, as the subtle changes could not be detected by histological examination alone. One day after the rapid decline of the S-phase fraction, a 3-fold increase in apoptotic area was observed that remained for about 3 days and then gradually decreased. This correlated with the histologically observed reduction of tumour cells. In spite of the major cell loss, regression came to a halt after about 10 days. The surviving cell fraction is discussed within the context of a stem cell hypothesis, in which tumour cells with stem cell characteristics are less susceptible to hormone-induced apoptosis than their (non-stem) daughter cells. This notion has implications for the eradication of residual tumour cells, because a diminished susceptibility might also apply to apoptosis induced by radio- or chemotherapy.

Apoptosis (programmed cell death) can be difficult to detect in routine histological sections. Since extensive DNA fragmentation is an important characteristic of this process, visualization of DNA breaks could greatly facilitate the identification of apoptotic cells. We describe a new staining method for formalin-fixed, paraffin-embedded tissue sections that involves an in situ end-labeling (ISEL) procedure. After protease treatment to permeate the tissue sections, biotinylated nucleotides are in situ incorporated into DNA breaks by polymerase and subsequently stained with DAB via peroxidase-conjugated avidin. Staining of cells with the morphological characteristics of apoptosis was demonstrated in tissues known to exhibit programmed cell death, i.e., prostate and uterus after castration, tumors, lymph node follicles, and embryos. Apoptotic cells could be discriminated morphologically from areas of labeled necrotic cells, in which DNA degradation also occurs. Because apoptosis is relatively easily recognized in H&E-stained sections of involuting prostates of castrated rats, we used this model system to validate the ISEL method for the quantification of apoptotic cells. A high correlation was found between the fractions of ISEL-labeled cells and the fractions of apoptotic cells that were morphologically determined in adjacent sections. We conclude that ISEL is a useful technique for quantification of apoptosis in paraffin sections, especially for those tissues in which morphological determination is difficult. Furthermore, this new staining method enables the use of automated image cytometry for evaluating apoptosis.