Abstract
Pediatric surgeons have the privilege to care for patients at every stage of human development, from the fetus to the fully developed young adult. As such, we must cultivate and advance an all-encompassing knowledge base ranging from obstetrics to pediatrics to adult medicine and surgery. This unique, sweeping perspective on human disease requires an equally broad approach to research, which in our field is as vast and varied as it is stimulating.
Access provided by CONRICYT-eBooks. Download chapter PDF
Similar content being viewed by others
Keywords
1 Introduction
Pediatric surgeons have the privilege to care for patients at every stage of human development, from the fetus to the fully developed young adult. As such, we must cultivate and advance an all-encompassing knowledge base ranging from obstetrics to pediatrics to adult medicine and surgery. This unique, sweeping perspective on human disease requires an equally broad approach to research, which in our field is as vast and varied as it is stimulating.
Yet, despite the appeal of research in such a diversified and vibrant spectrum, the relative proportion of pediatric surgeons performing research appears to have been dwindling in recent years. While different factors can be debated as implicated in this scenario, perhaps one should be emphasized, namely the increasingly restricted exposure to research during training. The greater significance of this trend lies in the fact that, unlike most other components of this conjuncture, it has career-long consequences, rendering the unexposed trainees essentially unable to develop as independent investigators once they become practicing pediatric surgeons, notwithstanding the eventual will to do so. Regrettably, fewer and fewer countries and institutions can afford the time and resources necessary for surgical trainees to develop a strong research background.
While the recent emphasis on a multidisciplinary approach to research has allowed for many developments that would not have been possible in isolation, we must aspire to a central role within research groups related to our specialty. Clinical expertise is often a pre-requisite for one to provide consequential guidance to the powerful scientific methodology currently available and the perspective offered by the pediatric surgeon cannot be replaced. By the same token, only we can protect and expand the role of research in the education of our future peers. This chapter is aimed at tendering some support, however limited, to this need.
It would be beyond the scope of any book chapter to present a comprehensive, exhaustive review of all the possible developments applicable to research in Pediatric Surgery. Here, we present a summarized overview of different aspects involving both laboratory- and clinical-based research that should be of interest to both trainees and practicing colleagues, through select examples representative of the far reach of our field. Our focus will be on translational research, as this is typically the chief dominion of the pediatric surgeon, as opposed to that of the basic scientist.
2 Animal Models
Although much can be learned from in vitro analyses of intracellular processes and defined cellular manipulations, especially in light of recent developments in cellular reprogramming, the complexity of organ systems or whole organisms cannot yet be substituted. Both developmental and interventional research pursuits still depend heavily on animal models, which remain the workhorses at most pediatric surgical laboratories.
There is now an overwhelming variety of animal models for research, spanning widely across taxonomic groups [1]. A few basic considerations should guide animal selection for a given experiment. One is of course the degree of correspondence to the human disease or biological process of interest. The options here are perhaps surprisingly broad, depending on the subject, not infrequently including significantly less prescient species, such as in the zebra fish model of lymphatic malformation, in addition to more predictable mammals. At the same time, species-specific variations in physiology and anatomy can render certain higher species essentially irrelevant to a given human disease process. For example, a swine model of naturally occurring congenital diaphragmatic hernia (CDH) (Sus scrofa) does not include pulmonary hypoplasia, virtually ubiquitous to CDH in human infants.
Another consideration is the availability of genetic tools conducive to in depth molecular and pathway-specific analyses of mechanisms behind the phenomena being studied. Mice (Mus musculus) constitute the prime representative of that set of considerations, not the least due to the plethora of knockout and knock-in murine models, though the thornier rat knockouts have also become options in the last several years. The International Mouse Phenotyping Consortium is striving to create viable strains of identical genetic background mice in which only one of the approximately 20,000 genes in the mouse genome can be selectively deactivated for systematic phenotypic screens, further expanding the scope of the murine genetic manipulation platform [2]. The more recent development of the first cloned rat also paves the way for the establishment of overexpression rat models based on targeted insertions [3].
Yet another consideration of special appeal to pediatric surgery is tolerance to fetal manipulation/intervention. While this can be accomplished in a number of species, sheep (Ovis aries) deserves special attention due to their inordinately high tolerance to such manipulations, the size of their fetuses and newborns, and the easily manageable gestational times. The ovine model can also be an asset to an additional aspect to be taken into consideration when selecting an animal model, namely is fast growth rate combined to the fact that their sizes are comparable to that of humans, from infancy to adulthood. Meaningful growth is often a pre-requisite to pediatric surgical research, for example in projects involving different forms of structural repair.
Expectedly, as always, logistical and financial constraints come into play as well. The following is a brief review of select animal models of interest to certain specific groups of pediatric surgical diseases, as representative illustrations of the breadth of animal research in our field. Other lists equally focused on our specialty, though based on somewhat different criteria, should also be of particular interest to the reader [4].
2.1 Abdominal Wall Defects
Not infrequently, a given structural congenital anomaly can be modeled in animals by either of five methods: surgery; genetic manipulation ; drugs/chemicals; other environmental manipulations; or it may be naturally occurring. Selecting which one best correlates with the clinical disease is not always straightforward, especially when the etiology of the human condition is unknown. Animal models of gastroschisis and omphalocele illustrate that scenario.
There is an inbred mouse strain, namely HLG/Zte, in which gastroschisis occurs spontaneously. The typical prevalence of 3% can be increased with irradiation during pre-implantation development [5]. Studies with these animals have identified a region of the mouse chromosome 7 as a responsible locus [6]. Further similar studies may shed more light on genes eventually involved in the development of abdominal wall defects.
Abdominal wall defects can also be induced experimentally with a variety of teratogens. However, these agents typically lead to inconsistent results, as well as multiple associated anomalies. Aminpyrine causes omphalocele when given to pregnant mice at midgestation [7]. This can be augmented by supplementation with barbital [8]. In rats, omphaloceles have been induced with maternal exposure to DA-125 (anthracycline antineoplastic agent) [9], beta-aminoprpioitrile [10], or flubendazole [11]. Additional teratogenic agents have been explored in assorted species, including doxorubicin hydrochloride [12], ethanol [13, 14], nitrous oxide [15], ethylene glycol [16], scopolamine hydrobromide [17], acetazolamide [18], and cyclooxygenase inhibitors [19]. The rate of gastroschisis in this studies, however, is somewhat limited, ranging from 3.7 to 19.8%. In guinea pigs, a daily period of maternal hyperthermia can result in abdominal wall defects, among other abnormalities [20].
Various species have been used in surgical models of gastroschisis, the most prominent of which are sheep, rabbit, and the chicken embryo. Haller et al. first described a sheep model of gastroschisis by operating on fetal lambs at midgestation and excising a full thickness disk of abdominal wall lateral to the umbilical cord [21]. The exposed intestine in surviving fetuses was edematous and matted, similar to the findings in humans. Langer and colleagues later modified this model by placing a silastic ring in the abdominal wall defect [22,23,24]. Though this design was associated with a relatively high rate of spontaneous abortion, it demonstrated that intestinal damage correlates with the time of exposure to the amniotic fluid. Less costly rabbit models of gastroschisis have also been described [25, 26]. Improvements in experimental fetal surgery have improved the success rate of this model to the range of 80–90% [27, 28]. An interesting modification of the leporine model has been described so as to remove the effect of amniotic fluid exposure on the intestinal damage during fetal development [29]. The least costly models for gastroschisis involve chicken embryos. The chicken embryo is enveloped in amniotic fluid and a number of membranes. After confirming fertility of an egg, a 1 cm defect is created in the shell. Using the allantoic vessels and the umbilical cord as landmarks, the physiologic umbilical hernia sac can be incised in order to create a gastroshisis [30]. Using this model, the effects of amniotic fluid exchange as a means to reduce the severity of intestinal damage have been studied [31,32,33].
2.2 Biliary Atresia
Multiple theories have been proposed to account for the varied spectrum of pathology in biliary atresia, ranging from putative congenital malformations of the bile ducts to the presence of a causative infectious agent. Reflecting this diversity, several types of models have been described.
Lampreys provide an arguable natural model for biliary atresia. Adult lampreys are the only vertebrates with an absence of a bile duct system in their livers. This occurs through programmed degeneration of the biliary tract during normal morphogenesis [34]. As the biliary tract regresses, the adult lamprey develops progressive cholestasis and bile pigment accumulation. The spectrum of pathology resembles the human form of the biliary atresia with the accumulation of luminal debris, basement membrane thickening, disorganization of hepatic architecture, extra-hepatic bile duct atresia, and shrinkage or loss of the gall bladder [35]. These animals live for several years after biliary tract regression allowing for studies on compensatory response to cholestasis as well as changes in the evolution of biliary atresia at the molecular level [36].
Bile duct injury has been induced with several agents in an attempt to mimic histological features of biliary atresia. After having identified low levels of L-proline in the serum of patients with biliary atresia, Vacanti and Folkman were able to induce bile duct enlargement with a continuous intraperitoneal infusion of L-proline [37]. 1,4-phenylenediisothiocyanate (PDT), an antihelminthic agent, can be employed to induce bile duct inflammation [38, 39]. The bile duct pathology is related to the timing of exposure to this agent. When gavaged in the postnatal period, PDT causes bile duct enlargement. When gavaged to pregnant rats, PDT causes fibrosis in the bile ducts. However, with a combination of gavage to the pregnant rats and during the postnatal period, the bile ducts exhibit wall thickening with stenosis and atresia. Further study of this temporal relationship may aid in the understanding of bile duct development. Another agent, phorbol myristate acetate (PMA), has been infused directly into the gallbladders of adult rats with a subcutaneous pump [40]. After a 28-day infusion, portal fibrosis and neo-cholangiogenesis were observed. PMA is a nonspecific activator of inflammation and may lead to insights on the role of inflammation in the development of biliary atresia.
Surgical models involving ligation of the fetal bile duct have been described in sheep [41]. Although the distal bile duct can become atretic, similarly to what is found in the human form of biliary atresia, the same does not apply to the impact on the liver, which does not correlate with what is found in the human disease. More recently, it has been shown, also in the ovine model, that occlusion of the fetal bile duct and the consequent hyperarterialization of the liver actually/instead significantly affects hepatic hematopoiesis, leading to a new perspective into the mechanisms that govern hematopoiesis in general, illustrating the potentially far reaching impact of fetal surgical models [42].
2.3 Congenital Diaphragmatic Hernia
Multiple animal models of congenital diaphragmatic hernia (CDH) have been described, however only few bear relevance to the human disease.
A model of familial CDH has been described in pigs which were originally bred to produce anorectal malformations, with a prevalence of approximately 10% [43]. Animals show herniated intra-abdominal organs within the thoracic cavity, but not the pulmonary hypoplasia characteristic of CDH. Several genetically manipulated mice models have also demonstrated CDH in combination with other associated malformations. If both murine retinoic acid receptors are deleted, mice have a high incidence of cranial, vertebral, limb, cardiac, foregut and pulmonary malformations, in addition to occasional CDH [44, 45]. Mutations in the homeobox Hlx gene result in CDH with large lungs and small livers [46]. Homozygous inactivation of WT-1 causes CDH and major defects in the urogenital system [47]. Knockout mice homozygous for Slit3 deficiency exhibit CDH in a ventral midline location with herniation of the liver and gallbladder, along with renal and ureteral agenesis [48].
The first surgical model of CDH was described by De Lorimier using third trimester fetal lambs [49]. Through a maternal hysterotomy and a fetal thoracotomy, a large defect was created in the left dome of the diaphragm. This model resulted in hypoplastic lungs, however with essentially normal pressure-volume curves. Further studies using an inflatable balloon in the fetal chest produced significantly reduced tidal volume and pulmonary compliance compared with control animals [50, 51]. Deflation of the balloon in utero improved these pathophysiologic effects and improved newborn survival [50]. In another variation of fetal manipulation, the diaphragmatic defect was created in the second trimester rather than the third, in order to more closely mimic the human disease [52]. In these animals, the lungs were hypoplastic, had abnormal airway branching, and a smaller and more muscularized pulmonary arterial tree when compared with controls [53, 54]. The fetal surgical model of CDH has also been described and further explored in rabbits [55,56,57]. As these surgical models are created during fetal life, they hold limited significance to the embryogenesis of CDH.
Experimental CDH can also be produced in other animal species through different interventions, other than surgical creation of the defect, including: exposure to diet deficient in either vitamin A [58, 59], zinc [60], or cadmium [61]; administration of either thalidomide [62], anti-rat rabbit serum [63], 2,4-diclorophenil-p-nitrofenilic ether (nitrofen, a herbicide) [64,65,66], or polibromate biphenils [67, 68]; and genetic manipulations, such as FOG-2, COUP-TFII, and GATA-4 mutations [69,70,71]. However, with the possible exception to the nitrofen model, there’s been no conclusive relationship between these experimental models and clinical/epidemiological data in humans. The nitrofen model has been increasingly accepted as the most relevant to clinical CDH due to the fact that, in that model, the pulmonary hypoplasia precedes the diaphragmatic defect and is independent from the latter. This is in accordance with today’s favored notion that the primary defect is not in the diaphragm, but rather in the developing lung buds, with the diaphragmatic defect being actually secondary to a primary pulmonary hypoplasia. Such pulmonary hypoplasia, in turn, could be made worse by the herniated content into the chest.
Laboratory developments in CDH include a peculiar facet which further epitomizes the impact that fetal intervention models can have in our understanding of not only a given disease, but also of germane biological processes. In the sixties, Carmel and colleagues used a healthy leporine model to demonstrate that fetal tracheal occlusion induced lung growth [72]. In the seventies, Alcorn et al. suggested, in a healthy ovine model, that fetal tracheal occlusion and drainage led to hyperplasia and hypoplasia of the lungs, respectively [73]. It was not until the early nineties, however, that Wilson et al. showed, also in sheep, that fetal tracheal occlusion could actually be a means to reverse the pulmonary hypoplasia associated with both CDH and fetal nephrectomy [74,75,76]. Wilson’s sentinel studies on therapeutic fetal tracheal occlusion have triggered one of the most fertile experimental and clinical development sprees of recent memory in our specialty, with ramifications that have crossed the boundaries of our field.
2.4 Hirschsprung’s Disease
A number of animal species have naturally occurring aganglionic megacolon, including mice, rats and horses [77,78,79]. In 1966, Lane described two strains of mice with autosomal recessive aganglionosis [79]. The lethal spotting (ls) mice have approximately 2 mm of aganglionosis while piebald lethal (s1) mice have approximately 10 mm of aganglionosis. Lane and Liu also described megacolon associated with a dominant spotting gene (Dom) in mice, characterized by distal colonic aganglionosis and a long hypoganglionic transition zone [78]. Ikadai and Agematsu described an autosomal recessive total colonic aganglionosis in a strain of rats [77]. These animals have a high mortality rate and are only able to survive for 3–4 weeks after birth, eventually succumbing to severe bowel obstruction and enterocolitis. Histological studies using acetyl cholinesterase whole-mounts in all these rodent models are virtually identical to the human histopathology [80].
Various genes have been actively disrupted in mice, producing phenotypes similar to human Hirschsprung’s Disease (HD). The Ret gene encodes a receptor tyrosine kinase, which has four ligands: glial cell line derived growth factor (GDNF), neurturin (NTN), artemin (ATM) and persephin (PSP) [81]. The complete receptor complex includes the Ret receptor tyrosine kinase and a glycosylphosphatidylinositol-anchored binding component (gfrα1, gfrα2, gfrα3 or gfrα4). This receptor has been suggested to function as an adhesion molecule, which is required for neural crest migration and could also play a role in either differentiation or survival of the neural crest cells which have stopped migrating [82, 83]. Ret (−/−) transgenic mice have a homozygous, targeted mutation of the tyrosine kinase receptor resulting in a loss of its function. These mice exhibit total intestinal aganglionosis and renal agenesis [84]. The Ret gene has been demonstrated to be a major gene causing HD in humans. Mutations of Ret account for 50% of familial and 15–20% of sporadic cases of HD [85,86,87,88]. GDNF, one of the Ret receptor ligands, stimulates the proliferation and survival of neural crest derived precursor cells in the embryonic gut [89, 90]. Mice homozygous for null mutation in Ret, GDNF and gfrα1 have almost identical phenotypes characterized by failure of enteric nervous system development distal to the esophagus and absent kidneys [84, 91,92,93,94,95]. Although a causative role for GDNF mutations in some patients with HD has been suggested, the occurrence of such cases is uncommon. It is more likely that the GDNF mutations are involved via its interaction with the Ret receptor [96, 97]. No gfrα1 mutations have been identified in patients with HD [98].
Endothelins are intercellular local messengers that comprise four members to date: ET-1, ET-2, ET-3 and VIP. They transduce a signal via two cell surface transmembrane receptors: ENDR-A and ENDR-B [81]. Both ET-3 and ENDR-B genes have been disrupted and have been identified as the cause for the natural mutants lethal spotting mice and piebald lethal mice, respectively [99, 100]. Moreover, a transgenic mouse ENDR-B knockout has a phenotype identical to the piebald lethal mouse [101]. As the connection between mutations in the Ret receptor and familial HD was established, ET-3 and ENDR-B mutations were also implicated in the disease [99, 100, 102]. However, these mutations have been demonstrated in less than 10% of the cases of HD in humans [103]. Endothelins are initially produced as an inactive proendothelin that has to be activated by a specific enzyme, the endothelin-converting enzyme (ECE). Two ECE genes have been described, ECE-1 and ECE-2 [81]. ECE-1 knockout mice show craniofacial and cardiac abnormalities in addition to colonic aganglionosis [104]. A heterozygous ECE-1 mutation has been identified in a patient with HD who also had craniofacial and cardiac defects [105].
Sox10 is a member of the SRY-related family of transcription factors that is expressed by enteric nervous system precursors before and throughout colonization of the gut mesenchyme [81]. Disruption of the Sox10 gene has been demonstrated to be the cause of the Dom mouse natural mutant [106, 107]. Interestingly, both homozygous and heterozygous animals produce a lethal HD-like phenotype [108]. Mutations in Sox10 have been identified in Waardenburg syndrome associated with HD [109].
Phox2B is a transcription factor that is essential for the development of the neural crest derivates as it regulates the Ret expression in enteric nervous system precursors [110, 111]. Targeted Phox2B gene disruption leads to a complete absence of enteric nervous system in the mice, a phenotype that is very similar to that of the Ret knockout mouse [110]. Garcia-Barcelo et al. reported that Phox2B deficiency might predispose to HD in humans [112].
Pax3 is a member of the paired-box containing family of nuclear transcription factors that is expressed in neural cell precursors giving rise to enteric ganglia and synergizes with Sox10 to activate an enhancer in the Ret gene [113]. In the mouse, Pax3 mutations result in a phenotype characterized by deficient enteric ganglia in the heterozygous state. Homozygous deficient embryos die during mid-gestation with neural tube defects, cardiac defects and absence of enteric ganglia [113]. So far, no Pax3 mutations have been identified in patients with HD, though.
Most surgical models of HD have involved chick embryos because they are easily accessible and the development of their enteric nervous system has been well studied. In that species, aganglionosis can be caused by surgical ablation of the premigratory neural crest [114]. This model is useful for the investigation of possible treatment strategies. It has been used to recolonize aganglionic bowel with neural crest cells by transplanting tissue obtained from the dorsal neural tube [115,116,117]. It has also been employed to show that neurons from more proximal regions of bowel are capable of recolonizing distal bowel and forming enteric ganglia [115, 118].
Sato and colleagues described a chemical model of HD [119]. They created segmental aganglionosis by applying benzalkonium chloride topically to the colon and rectum in rats. This model has been reproduced in mice and guinea pigs [120, 121]. It has also been used in the distal esophagus as a model of achalasia [122]. Benzalkonium chloride causes cell damage and death by producing an irreversible depolarization of the cell membrane. Due to the high cell membrane negative charge of neurons, they are more intensely affected then other cells. As a result, benzalkonium chloride induces a selective neuronal ablation in the intestinal wall eliminating almost all myenteric neurons and glia in treated segments [121]. Although the aganglionic bowel does not show hypertrophic nerve bundles and the chemical does not affect the number of submucosal neurons, the treated part does become narrowed and the rectoanal reflex is abolished [119]. Compared to the other models of HD, this technique is inexpensive, easy to perform and the animals can survive longer. It has been used to study functional and structural changes in the bowel resulting from loss of these neural elements. It could also be used to study the chronic changes caused by the aganglionic segment, as well as the long-term effects of different surgical treatments [123,124,125,126,127,128].
2.5 Necrotizing Enterocolitis
To date, no true animal model for necrotizing enterocolitis (NEC) has been described. Nevertheless, as multiple factors have been implicated in the pathogenesis of NEC, several animal models exist that may provide useful platforms for the study of different aspects relevant to the pathophysiology of this disease.
The ischemia/reperfusion model involves direct occlusion of mesenteric vessels or the superior mesenteric artery for varied periods of time followed by reperfusion. It has been performed in different species. In one study in neonatal piglets, the mesenteric vessels were tied off at different points near the distal ileum for 48 h [129]. There was a higher chance of intestinal injury when the occlusion was closer to the ileocecal junction. The degree of injury was greatest in low birth weight piglets as measured by ulceration, vascular engorgement, pneumatosis intestinalis, full-thickness necrosis, and ulceration with perforation. In normal birth weight piglets no injury was observed. This model allows for the investigation of eventual differences in the intestinal response to injury dependent on developmental stages. In mice, the time for the development of ischemic injury following vascular occlusion is substantially less than in low birth weight piglets. For example, occlusion of the superior mesenteric artery for 20 min in adult mice can result in the development of ischemic intestinal lesions in 50% of the animals by 48 h [130].
Studies in human infants with NEC have shown that, within the intestinal lumen, the pH was generally less than 5.0, the protein content less than 5 g/dL, and sufficient carbohydrate and bacteria were available to produce organic acids by fermentation [131]. Based on these data, investigators have created a rabbit model of NEC using a bovine casein formulation acidified with propionic acid [131, 132]. In weanling rabbits, either saline or a solution of 10 mg/mL casein and 50 mg/mL calcium gluconate acidified to a pH of 4.0 was instilled into isolated intestinal loops triggering increased intestinal blood flow, mucosal permeability and histamine release. After 3 h, the villa were blunted, the lymphatic vessels dilated and edema was observed [133]. After 16 hours, several rabbits had hemorrhagic necrosis and died. Advantages of this model include its simplicity and reproducibility as well as the fact that assorted animals at varied stages of development can be evaluated as to their response.
2.6 Short Bowel Syndrome
Perhaps not surprisingly, many models of short bowel syndrome (SBS) have been described. For example, intestinal resection and subsequent gut adaptation have been characterized in the pig [134, 135], dog [136,137,138], rat [139, 140], and mouse [141]. Warner and colleagues have shown that the murine model can be particularly useful for the study of various genes germane to intestinal adaptation [141]. In this model, a proximal resection is preferred, as adaptive changes are most pronounced in the distal intestine. Large animal models such as the pig are more useful for the development of new surgical bowel lengthening techniques [142,143,144].
2.7 Parenteral Nutrition
Now exceedingly rare due to animal welfare regulations, canine models were instrumental to one of the most relevant achievements not only in pediatric surgery, but in all of medicine and surgery, namely the ability to sustain life exclusively by parenteral nutrition, chiefly through the work of Dudrick and colleagues [145]. In their original study, the aim was to support growth and development in beagle puppies for 10 weeks [146]. Small lipoid pigment deposits and hemosiderin pigment were present in the liver, so dosages of fat and iron were reduced. These results lead to a subsequent study in which 6 beagle puppies were fed entirely by central venous infusion for 72 to 256 days and compared with their littermates [147]. These puppies exceeded their orally fed control littermates in weight gain and matched them in skeletal growth, development, and activity for the study period. The longest-term animals, fed for 235 and 256 days, more than tripled their body weight and developed comparably to their control littermates. These studies first demonstrated that it was both possible and practical to feed animals entirely by vein for prolonged periods of time without excessive risks or compromise of growth and development. Soon thereafter, Dudrick and colleagues administered total parenteral nutrition to six severely malnourished adult patients with chronic, severe gastrointestinal disease for up to 48 days [148]. Positive nitrogen balance was achieved in all of them, along with weight gain, normalized wound healing, and increased activity. All patients were eventually discharged from the hospital. The first neonatal administration occurred in that same year, in an infant with near-total small bowel atresia who underwent a massive intestinal resection [149].
2.8 Vacter and Other Models
As previously stated, this was not to be an all-inclusive list, but rather one illustrative of the different development avenues offered by a variety of animal platforms. Other models applicable to the pediatric surgical diseases discussed above, as well as models of interest to other pathological processes, will be discussed in their respective chapters. A special note must be mentioned on the remarkable variety of models of the VACTER (vertebral, anorectal, cardiac, trachea-esophageal, and renal) association, both as far as mechanism of action, as well as variability within the broad spectrum of this “syndrome” [4, 150,151,152,153,154,155,156,157,158,159].
3 Cell-Based Research
Cell-based therapies remain largely experimental, yet cell-based research has undergone dramatic growth and diversification over the last few decades. Certainly, in light of recent advances in stem cell biology, tissue engineering, gene manipulations, and other so-called regenerative medicine strategies, it is reasonable to speculate that these therapies may become alternatives, if not preferred treatment modalities, for a number of structural congenital anomalies and other diseases within the realm of pediatric surgery in the not so distant future [160, 161]. The following is a much summarized outline of a few aspects of this burgeoning field that are of particular consequence to our specialty.
Prenatal stem cell and gene therapies have tremendous potential to treat a range of disorders that can be diagnosed or predicted before birth, stemming from the unique environment present during fetal developmental, which can facilitate and enhance cellular engraftment. A notable example is in utero hematopoietic stem cell transplantation (IUHSCT) . While few disorders have a compelling rationale for IUHSCT based on the prevention of irreversible damage to the fetus before birth, such as for example glycogen storage diseases with neurologic involvement, this methodology can be a powerful means to induce tolerance to transplantation later in life. Flake and colleagues have developed germane work in this area aimed at maximizing chimerism through a variety of strategies so as to achieve complete or near complete replacement of host hematopoiesis by donor cells without toxicity or graft versus host disease in rodent models [162,163,164]. Consistent results in preclinical large animal models are now being pursued by that group and others [165].
Fetal tissue engineering is another notable development. It constitutes a novel therapeutic concept in perinatal surgery, involving the procurement of fetal cells, which are then used to engineer tissue in vitro in parallel to the remainder of gestation, so that an infant, or a fetus, with a prenatally diagnosed birth defect could benefit from having autologous, expanded tissue readily available for surgical implantation in the perinatal period. The fetus is a prime tissue engineering subject, both as a donor and as a host. The many exclusive characteristics of fetal cells, in conjunction with the developmental and long-term impacts of engineered graft implantation into a fetus or a newborn, add new dimensions to tissue engineering generally. Also, the fact that certain congenital anomalies present as perinatal surgical emergencies further justifies the fetal tissue engineering principle. Our group and others have been developing this notion in a variety of animal models of structural congenital anomalies, typically employing the amniotic fluid as a preferred source of fetal cells [166,167,168,169,170,171,172,173,174,175,176,177,178,179,180]. Preclinical studies have been reported and the first clinical trials are expected for the near future [181,182,183]. Another facet of fetal cell-based treatments of structural anomalies being developed experimentally is the use of fetal neural stem cells for the repair of spinal cord damage in the setting of neural tube defects, such as spina bifida [184]. Additionally, select fetal cells have also been proven valuable experimentally in studies on wound healing modulation [185].
Tissue engineering techniques have already been used to repair congenital anomalies postnatally in children. Shin’oka and colleagues have accumulated considerable clinical experience with the use of engineered conduits as vascular replacements in low-pressure systems, in children with varying forms of complex congenital cardiovascular anomalies [186,187,188,189,190]. Further clinical experience with tissue engineering in pediatric surgery beyond the more prevalent anecdotal reports is expected in the coming years.
More recently, transamniotic stem cell therapy (TRASCET) has emerged experimentally as a novel therapeutic strategy for the treatment of different birth defects. It is based on the principle of harnessing/enhancing the normal biological role of mesenchymal stem cells that are naturally occurring in the amniotic fluid for therapeutic benefit. Specifically, we have recently shown that amniotic fluid-derived mesenchymal stem cells (afMSCs) play a central role in fetal wound healing, widely known to be enhanced when compared with postnatal repair of tissue damage [185]. This germane finding was not only the first demonstration of a biological role for any amniotic cell, it has also provided validation for the use of afMSCs in regenerative strategies, in that these cells already play a regenerative role in nature. More recently, we have also shown, in different animal models, that the simple intra-amniotic delivery of afMSCs in large numbers can either elicit the repair, or significantly mitigate the effects associated with major congenital anomalies, putatively by boosting the activity that these cells normally have. For example, concentrated amounts of these cells injected into the amniotic cavity can induce partial or complete coverage of experimental spina bifida by promoting the local formation of a host-derived primitive skin, thus protecting the spinal cord from damage [191, 192]. Placenta-derived MSCs also seem to be a suitable option for TRASCET, at least in experimental spina bifida [193]. In another example, TRASCET has been shown to significantly alleviate the bowel damage associated with gastroschisis [194]. Many other applications of this practical therapeutic concept, involving a variety of congenital anomalies, are currently being investigated.
4 Clinical Research
Clinical research has evolved appreciably, particularly over the last two decades. It has essentially become a science deserving of a whole book, rather than a segment of a book chapter. The several aspects that make up clinical research need careful planning and execution if a study is to be any relevant. More specifically, conceiving the research question(s); establishing the appropriate study/trial format; defining randomization criteria when suitable; choosing and recruiting the research subjects; estimating sample size and power; assessing control/independent variables and/or causal interference; designing questionnaires and interviews; organizing and managing databases; analyzing data; implementing quality control; and addressing ethical issues are just some of the components that need to be tackled before one can embark on a meaningful project. By the same token, as the clinical research endeavor becomes more refined, it expectedly subdivides, perhaps more notably between clinical trials and outcomes research.
As critical as it is to any medical/surgical field, the overall adequacy of clinical research design and reporting in our specialty has been rather inconsistent over time [195]. Fortunately, however, pediatric surgeons have grown increasingly more discerning of late, progressively driving our scientific journals and professional societies to implement enhanced and more standardized peer-review guidelines which ultimately should be of great benefit to the field as a whole [195,196,197,198,199].
5 Final Considerations
The history of our young specialty is already rich in original translational initiatives which have shaped clinical practice both within and across the boundaries of our field. Among the many of these, perhaps one should stand out as an inspiration to all of us. A pediatric surgeon, Dr. M. Judah Folkman, was the first to propose and coin the term “antiangiogenesis” as a potential therapeutic approach to cancer and other conditions in his landmark paper of 1971 [200]. With this seminal insight, he established a new perspective on cancer biology by expanding the focus beyond the tumor cells to their microenvironment. The concept that proliferating endothelial cells may be better therapeutic targets than the neoplastic cells themselves represented a momentous shift of focus and triggered an enormous research enterprise. Folkman’s direct and rational approach to angiogenesis redefined cancer biology, as well as multiple other processes in health, embryonic development, and other diseases [201]. It has been predicted that angiogenesis-related therapies can eventually benefit half a billion people worldwide [202].
As Dr. Folkman used to say, “science goes where you imagine it”. Let us hope that more and more of our colleagues can be drawn by that inspirational vision and manage to incorporate either of the many forms of pediatric surgical research into their daily activities and ambitions.
References
Committee for the Update for the Care and Use of Laboratory Animals NRC. Guide for the care and use of laboratory animals. 8th ed. Washington, DC: The National Academies Press; 2011. p. 248.
Abbott A. Mouse project to find each gene's role. Nature. 2010;465(7297):410. Epub 2010/05/28
Zhou Q, Renard JP, Le Friec G, Brochard V, Beaujean N, Cherifi Y, et al. Generation of fertile cloned rats by regulating oocyte activation. Science. 2003;302(5648):1179. Epub 2003/09/27
Mortell A, Montedonico S, Puri P. Animal models in pediatric surgery. Pediatr Surg Int. 2006;22(2):111–28. Epub 2005/12/07
Hillebrandt S, Streffer C, Muller WU. Genetic analysis of the cause of gastroschisis in the HLG mouse strain. Mutat Res. 1996;372(1):43–51. Epub 1996/11/11
Hillebrandt S, Streffer C, Montagutelli X, Balling R. A locus for radiation-induced gastroschisis on mouse Chromosome 7. Mamm Genome. 1998;9(12):995–7. Epub 1999/01/09
Takeno S, Sumita M, Saito H, Sakai T. Strain differences in susceptibility to the embryotoxic effects of aminopyrine in mice. Res Commun Chem Pathol Pharmacol. 1987;57(3):409–19. Epub 1987/09/01
Nomura T, Isa Y, Kurokawa N, Kanzaki T, Tanaka H, Tada E, et al. Enhancement effects of barbital on the teratogenicity of aminopyrine. Toxicology. 1984;29(4):281–91. Epub 1984/02/01
Chung MK, Kim JC, Roh JK. Teratogenic effects of DA-125, a new anthracycline anticancer agent, in rats. Reprod Toxicol. 1995;9(2):159–64. Epub 1995/03/01
Barrow MV, Steffek AJ. Teratologic and other embryotoxic effects of beta-aminopropionitrile in rats. Teratology. 1974;10(2):165–72. Epub 1974/10/01
Yoshimura H. Teratogenicity of flubendazole in rats. Toxicology. 1987;43(2):133–8. Epub 1987/02/01
Mortell A, Giles J, Bannigan J, Puri P. Adriamycin effects on the chick embryo. Pediatr Surg Int. 2003;19(5):359–64. Epub 2003/06/13
Grinfeld H, Goldenberg S, Segre CA, Chadi G. Fetal alcohol syndrome in Sao Paulo, Brazil. Paediatr Perinat Epidemiol. 1999;13(4):496–7. Epub 1999/11/24
Beauchemin RR Jr, Gartner LP, Provenza DV. Alcohol induced cardiac malformations in the rat. Anat Anz. 1984;155(1–5):17–28. Epub 1984/01/01
Lane GA, Nahrwold ML, Tait AR, Taylor-Busch M, Cohen PJ, Beaudoin AR. Anesthetics as teratogens: nitrous oxide is fetotoxic, xenon is not. Science. 1980;210(4472):899–901. Epub 1980/11/21
Neeper-Bradley TL, Tyl RW, Fisher LC, Kubena MF, Vrbanic MA, Losco PE. Determination of a no-observed-effect level for developmental toxicity of ethylene glycol administered by gavage to CD rats and CD-1 mice. Fundam Appl Toxicol. 1995;27(1):121–30. Epub 1995/08/01
McBride WG, Vardy PH, French J. Effects of scopolamine hydrobromide on the development of the chick and rabbit embryo. Aust J Biol Sci. 1982;35(2):173–8. Epub 1982/01/01
Tellone CI, Baldwin JK, Sofia RD. Teratogenic activity in the mouse after oral administration of acetazolamide. Drug Chem Toxicol. 1980;3(1):83–98. Epub 1980/01/01
Cappon GD, Cook JC, Hurtt ME. Relationship between cyclooxygenase 1 and 2 selective inhibitors and fetal development when administered to rats and rabbits during the sensitive periods for heart development and midline closure. Birth Defects Res B Dev Reprod Toxicol. 2003;68(1):47–56. Epub 2003/07/11
Edwards MJ. Hyperthermia and congenital malformations in guinea-pigs. Aust Vet J. 1969;45(4):189–93. Epub 1969/04/01
Haller JA Jr, Kehrer BH, Shaker IJ, Shermeta DW, Wyllie RG. Studies of the pathophysiology of gastroschisis in fetal sheep. J Pediatr Surg. 1974;9(5):627–32. Epub 1974/10/01
Srinathan SK, Langer JC, Blennerhassett MG, Harrison MR, Pelletier GJ, Lagunoff D. Etiology of intestinal damage in gastroschisis. III: Morphometric analysis of the smooth muscle and submucosa. J Pediatr Surg. 1995;30(3):379–83. Epub 1995/03/01
Langer JC, Bell JG, Castillo RO, Crombleholme TM, Longaker MT, Duncan BW, et al. Etiology of intestinal damage in gastroschisis, II. Timing and reversibility of histological changes, mucosal function, and contractility. J Pediatr Surg. 1990;25(11):1122–6. Epub 1990/11/01
Langer JC, Longaker MT, Crombleholme TM, Bond SJ, Finkbeiner WE, Rudolph CA, et al. Etiology of intestinal damage in gastroschisis. I: Effects of amniotic fluid exposure and bowel constriction in a fetal lamb model. J Pediatr Surg. 1989;24(10):992–7. Epub 1989/10/01
Aoki Y, Ohshio T, Komi N. An experimental study on gastroschisis using fetal surgery. J Pediatr Surg. 1980;15(3):252–6. Epub 1980/06/01
Sherman NJ, Asch MJ, Isaacs H Jr, Rosenkrantz JG. Experimental gastroschisis in the fetal rabbit. J Pediatr Surg. 1973;8(2):165–9. Epub 1973/04/01
Nelson JM, Krummel TM, Haynes JH, Flood LC, Sauer L, Flake AW, et al. Operative techniques in the fetal rabbit. J Investig Surg. 1990;3(4):393–8. Epub 1990/01/01
Phillips JD, Kelly RE Jr, Fonkalsrud EW, Mirzayan A, Kim CS. An improved model of experimental gastroschisis in fetal rabbits. J Pediatr Surg. 1991;26(7):784–7. Epub 1991/07/11
Albert A, Julia MV, Morales L, Parri FJ. Gastroschisis in the partially extraamniotic fetus: experimental study. J Pediatr Surg. 1993;28(5):656–9. Epub 1993/05/01
Tibboel D, Molenaar JC, Van Nie CJ. New perspectives in fetal surgery: the chicken embryo. J Pediatr Surg. 1979;14(4):438–40. Epub 1979/08/01
Aktug T, Ucan B, Olguner M, Akgur FM, Ozer E, Caliskan S, et al. Amnio-allantoic fluid exchange for the prevention of intestinal damage in gastroschisis. III: Determination of the waste products removed by exchange. Eur J Pediatr Surg. 1998;8(6):326–8. Epub 1999/02/02
Aktug T, Ucan B, Olguner M, Akgur FM, Ozer E. Amnio-allantoic fluid exchange for prevention of intestinal damage in gastroschisis II: Effects of exchange performed by using two different solutions. Eur J Pediatr Surg. 1998;8(5):308–11. Epub 1998/11/24
Aktug T, Erdag G, Kargi A, Akgur FM, Tibboel D. Amnio-allantoic fluid exchange for the prevention of intestinal damage in gastroschisis: an experimental study on chick embryos. J Pediatr Surg. 1995;30(3):384–7. Epub 1995/03/01
Youson JH, Sidon EW. Lamprey biliary atresia: first model system for the human condition? Experientia. 1978;34(8):1084–6. Epub 1978/08/15
Sidon EW, Youson JH. Morphological changes in the liver of the sea lamprey, Petromyzon marinus L., during metamorphosis: I. Atresia of the bile ducts. J Morphol. 1983;177(1):109–24. Epub 1983/07/01
Makos BK, Youson JH. Tissue levels of bilirubin and biliverdin in the sea lamprey, Petromyzon marinus L., before and after biliary atresia. Comp Biochem Physiol A Comp Physiol. 1988;91(4):701–10. Epub 1988/01/01
Vacanti JP, Folkman J. Bile duct enlargement by infusion of L-proline: potential significance in biliary atresia. J Pediatr Surg. 1979;14(6):814–8. Epub 1979/12/01
Ogawa T, Suruga K, Kojima Y, Kitahara T, Kuwabara N. Experimental study of the pathogenesis of infantile obstructive cholangiopathy and its clinical evaluation. J Pediatr Surg. 1983;18(2):131–5. Epub 1983/04/01
Ogawa T, Suruga K, Kuwabara N. Experimental model of infantile obstructive cholangiopathy using 1,4-phenylenediisothiocyanate. Jpn J Surg. 1981;11(5):372–6. Epub 1981/01/01
Schmeling DJ, Oldham KT, Guice KS, Kunkel RG, Johnson KJ. Experimental obliterative cholangitis. A model for the study of biliary atresia. Ann Surg. 1991;213(4):350–5. Epub 1991/04/01
Spitz L. Ligation of the common bile duct in the fetal lamb: an experimental model for the study of biliary atresia. Pediatr Res. 1980;14(5):740–8. Epub 1980/05/01
Kunisaki SM, Azpurua H, Fuchs JR, Graves SC, Zurakowski D, Fauza DO. Fetal hepatic haematopoiesis is modulated by arterial blood flow to the liver. Br J Haematol. 2006;134(3):330–2. Epub 2006/07/20
Ohkawa H, Matsumoto M, Hori T, Kashiwa H. Familial congenital diaphragmatic hernia in the pig—studies on pathology and heredity. Eur J Pediatr Surg. 1993;3(2):67–71. Epub 1993/04/01
Mendelsohn C, Lohnes D, Decimo D, Lufkin T, LeMeur M, Chambon P, et al. Function of the retinoic acid receptors (RARs) during development (II). Multiple abnormalities at various stages of organogenesis in RAR double mutants. Development. 1994;120(10):2749–71. Epub 1994/10/01
Lohnes D, Mark M, Mendelsohn C, Dolle P, Dierich A, Gorry P, et al. Function of the retinoic acid receptors (RARs) during development (I). Craniofacial and skeletal abnormalities in RAR double mutants. Development. 1994;120(10):2723–48. Epub 1994/10/01
Hentsch B, Lyons I, Li R, Hartley L, Lints TJ, Adams JM, et al. Hlx homeo box gene is essential for an inductive tissue interaction that drives expansion of embryonic liver and gut. Genes Dev. 1996;10(1):70–9. Epub 1996/01/01
Kreidberg JA, Sariola H, Loring JM, Maeda M, Pelletier J, Housman D, et al. WT-1 is required for early kidney development. Cell. 1993;74(4):679–91. Epub 1993/08/27
Liu J, Zhang L, Wang D, Shen H, Jiang M, Mei P, et al. Congenital diaphragmatic hernia, kidney agenesis and cardiac defects associated with Slit3-deficiency in mice. Mech Dev. 2003;120(9):1059–70. Epub 2003/10/11
De Lorimier AATD, Parker HR. Hypoplastic lungs in fetal lambs with surgically produced congenital diaphragmatic hernia. Surgery. 1967;62(1):12–7.
Harrison MR, Bressack MA, Churg AM, de Lorimier AA. Correction of congenital diaphragmatic hernia in utero. II. Simulated correction permits fetal lung growth with survival at birth. Surgery. 1980;88(2):260–8. Epub 1980/08/01
Haller JA Jr, Signer RD, Golladay ES, Inon AE, Harrington DP, Shermeta DW. Pulmonary and ductal hemodynamics in studies of simulated diaphragmatic hernia of fetal and newborn lambs. J Pediatr Surg. 1976;11(5):675–80. Epub 1976/10/01
Adzick NS, Outwater KM, Harrison MR, Davies P, Glick PL, de Lorimier AA, et al. Correction of congenital diaphragmatic hernia in utero. IV. An early gestational fetal lamb model for pulmonary vascular morphometric analysis. J Pediatr Surg. 1985;20(6):673–80. Epub 1985/12/01
Ting A, Glick PL, Wilcox DT, Holm BA, Gil J, DiMaio M. Alveolar vascularization of the lung in a lamb model of congenital diaphragmatic hernia. Am J Respir Crit Care Med. 1998;157(1):31–4. Epub 1998/01/28
Lipsett J, Cool JC, Runciman SI, Ford WD, Kennedy JD, Martin AJ, et al. Morphometric analysis of preterm fetal pulmonary development in the sheep model of congenital diaphragmatic hernia. Pediatr Dev Pathol. 2000;3(1):17–28. Epub 1999/12/14
Wu J, Ge X, Verbeken EK, Gratacos E, Yesildaglar N, Deprest JA. Pulmonary effects of in utero tracheal occlusion are dependent on gestational age in a rabbit model of diaphragmatic hernia. J Pediatr Surg. 2002;37(1):11–7. Epub 2002/01/10
Fauza DO, Tannuri U, Ayoub AA, Capelozzi VL, Saldiva PH, Maksoud JG. Surgically produced congenital diaphragmatic hernia in fetal rabbits. J Pediatr Surg. 1994;29(7):882–6. Epub 1994/07/01
Roubliova X, Verbeken E, Wu J, Yamamoto H, Lerut T, Tibboel D, et al. Pulmonary vascular morphology in a fetal rabbit model for congenital diaphragmatic hernia. J Pediatr Surg. 2004;39(7):1066–72. Epub 2004/06/24
Andersen DH. Incidence of congenital diaphragmatic hernia in the young of rats bred on a diet deficient in vitamin A. Am J Dis Child. 1941;62:888.
Warkany J, Roth CB. Congenital malformations induced in rats by maternal vitamin A deficiency. II. Effect of varying the preparatory diet upon the yield of abnormal young. J Nutr. 1948;35:1–12.
Hurley LS. Teratogenic aspects of manganese, zinc, and copper nutrition. Physiol Rev. 1981;61(2):249–95.
Barr M Jr. The teratogenicity of cadmium chloride in two stocks of Wistar rats. Teratology. 1973;7(3):237–42.
Drobeck HP, Coulston F, Cornelius D. Effects of thalidomide on fetal development in rabbits and on establishment of pregnancy in monkeys. Toxicol Appl Pharmacol. 1965;7:165–78.
Brent RL. Antibodies and malformations. In: Tuchmann-Duplessis H, editor. Malformations Congénitales des Mammiféres. Paris: Masson City; 1971. p. 187–222.
Ambrose AM, Larson PS, Borzelleca JF, Smith RB Jr, Hennigar GR Jr. Toxicologic studies on 2,4-dichlorophenyl-p-nitrophenyl ether. Toxicol Appl Pharmacol. 1971;19(2):263–75.
Iritani I. Experimental study on embryogenesis of congenital diaphragmatic hernia. Anat Embryol. 1984;169(2):133–9.
Kluth D, Tenbrinck R, von Ekesparre M, Kangah R, Reich P, Brandsma A, et al. The natural history of congenital diaphragmatic hernia and pulmonary hypoplasia in the embryo. J Pediatr Surg. 1993;28(3):456–62. discussion 62–3
Beaudoin AR. Teratogenicity of polybrominated biphenyls in rats. Environ Res. 1977;14(1):81–6.
Sutherland MF, Parkinson MM, Hallett P. Teratogenicity of three substituted 4-biphenyls in the rat as a result of the chemical breakdown and possible metabolism of a thromboxane A2- receptor blocker. Teratology. 1989;39(6):537–45.
Ackerman KG, Herron BJ, Vargas SO, Huang H, Tevosian SG, Kochilas L, et al. Fog2 is required for normal diaphragm and lung development in mice and humans. PLoS Genet. 2005;1(1):58–65.
Jay PY, Bielinska M, Erlich JM, Mannisto S, WT P, Heikinheimo M, et al. Impaired mesenchymal cell function in Gata4 mutant mice leads to diaphragmatic hernias and primary lung defects. Dev Biol. 2007;301(2):602–14.
You LR, Takamoto N, CT Y, Tanaka T, Kodama T, Demayo FJ, et al. Mouse lacking COUP-TFII as an animal model of Bochdalek-type congenital diaphragmatic hernia. Proc Natl Acad Sci U S A. 2005;102(45):16351–6.
Carmel JA, Friedman F, Adams FH. Fetal Tracheal Ligation and Lung Development. Am J Dis Child. 1965;109:452–6. Epub 1965/05/01
Alcorn D, Adamson TM, Lambert TF, Maloney JE, Ritchie BC, Robinson PM. Morphological effects of chronic tracheal ligation and drainage in the fetal lamb lung. J Anat. 1977;123(3):649–60.
DiFiore JW, Fauza DO, Slavin R, Peters CA, Fackler JC, Wilson JM. Experimental fetal tracheal ligation reverses the structural and physiological effects of pulmonary hypoplasia in congenital diaphragmatic hernia. J Pediatr Surg. 1994;29(2):248–56. discussion 56–7
DiFiore JW, Fauza DO, Slavin R, Wilson JM. Experimental fetal tracheal ligation and congenital diaphragmatic hernia: a pulmonary vascular morphometric analysis [see comments]. J Pediatr Surg. 1995;30(7):917–23. discussion 23–4
Wilson JM, DiFiore JW, Peters CA. Experimental fetal tracheal ligation prevents the pulmonary hypoplasia associated with fetal nephrectomy: possible application for congenital diaphragmatic hernia. J Pediatr Surg. 1993;28(11):1433–9. discussion 9–40
Ikadai HFH, Agematsu Y. Observation of congenital aganglionosis rat and its genetical analsysis. Congenit Anom. 1979;19:31–6.
Lane PW, Liu HM. Association of megacolon with a new dominant spotting gene (Dom) in the mouse. J Hered. 1984;75(6):435–9. Epub 1984/11/01
Lane PW. Association of megacolon with two recessive spotting genes in the mouse. J Hered. 1966;57(1):29–31. Epub 1966/01/01
Cass DT, Zhang AL, Morthorpe J. Aganglionosis in rodents. J Pediatr Surg. 1992;27(3):351–5. discussion 5–6. Epub 1992/03/01
Puri P, Shinkai T. Pathogenesis of Hirschsprung's disease and its variants: recent progress. Semin Pediatr Surg. 2004;13(1):18–24. Epub 2004/02/07
Pouliot Y. Phylogenetic analysis of the cadherin superfamily. BioEssays. 1992;14(11):743–8. Epub 1992/11/01
Robertson K, Mason I. Expression of ret in the chicken embryo suggests roles in regionalisation of the vagal neural tube and somites and in development of multiple neural crest and placodal lineages. Mech Dev. 1995;53(3):329–44. Epub 1995/11/01
Schuchardt A, D'Agati V, Larsson-Blomberg L, Costantini F, Pachnis V. Defects in the kidney and enteric nervous system of mice lacking the tyrosine kinase receptor Ret. Nature. 1994;367(6461):380–3. Epub 1994/01/27
Martucciello G, Ceccherini I, Lerone M, Jasonni V. Pathogenesis of Hirschsprung's disease. J Pediatr Surg. 2000;35(7):1017–25. Epub 2000/08/05
Kusafuka T, Puri P. Altered RET gene mRNA expression in Hirschsprung's disease. J Pediatr Surg. 1997;32(4):600–4. Epub 1997/04/01
Edery P, Lyonnet S, Mulligan LM, Pelet A, Dow E, Abel L, et al. Mutations of the RET proto-oncogene in Hirschsprung's disease. Nature. 1994;367(6461):378–80. Epub 1994/01/27
Romeo G, Ronchetto P, Luo Y, Barone V, Seri M, Ceccherini I, et al. Point mutations affecting the tyrosine kinase domain of the RET proto-oncogene in Hirschsprung's disease. Nature. 1994;367(6461):377–8. Epub 1994/01/27
Young HM, Hearn CJ, Farlie PG, Canty AJ, Thomas PQ, Newgreen DF. GDNF is a chemoattractant for enteric neural cells. Dev Biol. 2001;229(2):503–16. Epub 2001/01/11
Worley DS, Pisano JM, Choi ED, Walus L, Hession CA, Cate RL, et al. Developmental regulation of GDNF response and receptor expression in the enteric nervous system. Development. 2000;127(20):4383–93. Epub 2000/09/27
Cacalano G, Farinas I, Wang LC, Hagler K, Forgie A, Moore M, et al. GFRalpha1 is an essential receptor component for GDNF in the developing nervous system and kidney. Neuron. 1998;21(1):53–62. Epub 1998/08/11
Tomac AC, Grinberg A, Huang SP, Nosrat C, Wang Y, Borlongan C, et al. Glial cell line-derived neurotrophic factor receptor alpha1 availability regulates glial cell line-derived neurotrophic factor signaling: evidence from mice carrying one or two mutated alleles. Neuroscience. 2000;95(4):1011–23. Epub 2000/02/22
Enomoto H, Araki T, Jackman A, Heuckeroth RO, Snider WD, Johnson EM Jr, et al. GFR alpha1-deficient mice have deficits in the enteric nervous system and kidneys. Neuron. 1998;21(2):317–24. Epub 1998/09/05
Pichel JG, Shen L, Sheng HZ, Granholm AC, Drago J, Grinberg A, et al. Defects in enteric innervation and kidney development in mice lacking GDNF. Nature. 1996;382(6586):73–6. Epub 1996/07/04
Sanchez MP, Silos-Santiago I, Frisen J, He B, Lira SA, Barbacid M. Renal agenesis and the absence of enteric neurons in mice lacking GDNF. Nature. 1996;382(6586):70–3. Epub 1996/07/04
Angrist M, Bolk S, Halushka M, Lapchak PA, Chakravarti A. Germline mutations in glial cell line-derived neurotrophic factor (GDNF) and RET in a Hirschsprung disease patient. Nat Genet. 1996;14(3):341–4. Epub 1996/11/01
Amiel J, Lyonnet S. Hirschsprung disease, associated syndromes, and genetics: a review. J Med Genet. 2001;38(11):729–39. Epub 2001/11/06
Martucciello G, Thompson H, Mazzola C, Morando A, Bertagnon M, Negri F, et al. GDNF deficit in Hirschsprung's disease. J Pediatr Surg. 1998;33(1):99–102. Epub 1998/02/24
Baynash AG, Hosoda K, Giaid A, Richardson JA, Emoto N, Hammer RE, et al. Interaction of endothelin-3 with endothelin-B receptor is essential for development of epidermal melanocytes and enteric neurons. Cell. 1994;79(7):1277–85. Epub 1994/12/30
Hosoda K, Hammer RE, Richardson JA, Baynash AG, Cheung JC, Giaid A, et al. Targeted and natural (piebald-lethal) mutations of endothelin-B receptor gene produce megacolon associated with spotted coat color in mice. Cell. 1994;79(7):1267–76. Epub 1994/12/30
Kapur RP, Yost C, Palmiter RD. A transgenic model for studying development of the enteric nervous system in normal and aganglionic mice. Development. 1992;116(1):167–75. Epub 1992/09/01
Puffenberger EG, Hosoda K, Washington SS, Nakao K, de Wit D, Yanagisawa M, et al. A missense mutation of the endothelin-B receptor gene in multigenic Hirschsprung's disease. Cell. 1994;79(7):1257–66. Epub 1994/12/30
Kusafuka T, Wang Y, Puri P. Mutation analysis of the RET, the endothelin-B receptor, and the endothelin-3 genes in sporadic cases of Hirschsprung's disease. J Pediatr Surg. 1997;32(3):501–4. Epub 1997/03/01
Yanagisawa H, Yanagisawa M, Kapur RP, Richardson JA, Williams SC, Clouthier DE, et al. Dual genetic pathways of endothelin-mediated intercellular signaling revealed by targeted disruption of endothelin converting enzyme-1 gene. Development. 1998;125(5):825–36. Epub 1998/05/09
Hofstra RM, Valdenaire O, Arch E, Osinga J, Kroes H, Loffler BM, et al. A loss-of-function mutation in the endothelin-converting enzyme 1 (ECE-1) associated with Hirschsprung disease, cardiac defects, and autonomic dysfunction. Am J Hum Genet. 1999;64(1):304–8. Epub 1999/01/23
Southard-Smith EM, Kos L, Pavan WJ. Sox10 mutation disrupts neural crest development in Dom Hirschsprung mouse model. Nat Genet. 1998;18(1):60–4. Epub 1998/01/13
Herbarth B, Pingault V, Bondurand N, Kuhlbrodt K, Hermans-Borgmeyer I, Puliti A, et al. Mutation of the Sry-related Sox10 gene in Dominant megacolon, a mouse model for human Hirschsprung disease. Proc Natl Acad Sci U S A. 1998;95(9):5161–5. Epub 1998/06/06
Kapur RP. Hirschsprung disease and other enteric dysganglionoses. Crit Rev Clin Lab Sci. 1999;36(3):225–73. Epub 1999/07/17
Kuhlbrodt K, Schmidt C, Sock E, Pingault V, Bondurand N, Goossens M, et al. Functional analysis of Sox10 mutations found in human Waardenburg-Hirschsprung patients. J Biol Chem. 1998;273(36):23033–8. Epub 1998/08/29
Gariepy CE. Intestinal motility disorders and development of the enteric nervous system. Pediatr Res. 2001;49(5):605–13. Epub 2001/05/01
Pattyn A, Morin X, Cremer H, Goridis C, Brunet JF. The homeobox gene Phox2b is essential for the development of autonomic neural crest derivatives. Nature. 1999;399(6734):366–70. Epub 1999/06/09
Garcia-Barcelo M, Sham MH, Lui VC, Chen BL, Ott J, Tam PK. Association study of PHOX2B as a candidate gene for Hirschsprung's disease. Gut. 2003;52(4):563–7. Epub 2003/03/13
Lang D, Chen F, Milewski R, Li J, Lu MM, Epstein JA. Pax3 is required for enteric ganglia formation and functions with Sox10 to modulate expression of c-ret. J Clin Invest. 2000;106(8):963–71. Epub 2000/10/18
Meijers JH, Tibboel D, van der Kamp AW, van Haperen-Heuts IC, Molenaar JC. A model for aganglionosis in the chicken embryo. J Pediatr Surg. 1989;24(6):557–61. Epub 1989/06/01
Rothman TP, Le Douarin NM, Fontaine-Perus JC, Gershon MD. Developmental potential of neural crest-derived cells migrating from segments of developing quail bowel back-grafted into younger chick host embryos. Development. 1990;109(2):411–23. Epub 1990/06/01
Gershon MD, Chalazonitis A, Rothman TP. From neural crest to bowel: development of the enteric nervous system. J Neurobiol. 1993;24(2):199–214. Epub 1993/02/01
Payette RF, Tennyson VM, Pomeranz HD, Pham TD, Rothman TP, Gershon MD. Accumulation of components of basal laminae: association with the failure of neural crest cells to colonize the presumptive aganglionic bowel of ls/ls mutant mice. Dev Biol. 1988;125(2):341–60. Epub 1988/02/01
Thiery JP, Duband JL, Delouvee A. Pathways and mechanisms of avian trunk neural crest cell migration and localization. Dev Biol. 1982;93(2):324–43. Epub 1982/10/01
Sato A, Yamamoto M, Imamura K, Kashiki Y, Kunieda T, Sakata K. Pathophysiology of aganglionic colon and anorectum: an experimental study on aganglionosis produced by a new method in the rat. J Pediatr Surg. 1978;13(4):399–435. Epub 1978/08/01
Parr EJ, Sharkey KA. Multiple mechanisms contribute to myenteric plexus ablation induced by benzalkonium chloride in the guinea-pig ileum. Cell Tissue Res. 1997;289(2):253–64. Epub 1997/08/01
Yoneda A, Shima H, Nemeth L, Oue T, Puri P. Selective chemical ablation of the enteric plexus in mice. Pediatr Surg Int. 2002;18(4):234–7. Epub 2002/05/22
Goto S, Grosfeld JL. The effect of a neurotoxin (benzalkonium chloride) on the lower esophagus. J Surg Res. 1989;47(2):117–9. Epub 1989/08/01
See NA, Epstein ML, Schultz E, Pienkowski TP, Bass P. Hyperplasia of jejunal smooth muscle in the myenterically denervated rat. Cell Tissue Res. 1988;253(3):609–17. Epub 1988/09/01
Luck MS, Dahl JL, Boyeson MG, Bass P. Neuroplasticity in the smooth muscle of the myenterically and extrinsically denervated rat jejunum. Cell Tissue Res. 1993;271(2):363–74. Epub 1993/02/01
Holle GE, Forth W. Myoelectric activity of small intestine after chemical ablation of myenteric neurons. Am J Phys. 1990;258(4 Pt 1):G519–26. Epub 1990/04/01
Holle GE. Changes in the structure and regeneration mode of the rat small intestinal mucosa following benzalkonium chloride treatment. Gastroenterology. 1991;101(5):1264–73. Epub 1991/11/01
Hadzijahic N, Renehan WE, Ma CK, Zhang X, Fogel R. Myenteric plexus destruction alters morphology of rat intestine. Gastroenterology. 1993;105(4):1017–28. Epub 1993/10/01
Dahl JL, Bloom DD, Epstein ML, Fox DA, Bass P. Effect of chemical ablation of myenteric neurons on neurotransmitter levels in the rat jejunum. Gastroenterology. 1987;92(2):338–44. Epub 1987/02/01
Sibbons PD, Spitz L, van Velzen D. Necrotizing enterocolitis induced by local circulatory interruption in the ileum of neonatal piglets. Pediatr Pathol. 1992;12(1):1–14. Epub 1992/01/01
Krasna IH, Howell C, Vega A, Ziegler M, Koop CE. A mouse model for the study of necrotizing enterocolitis. J Pediatr Surg. 1986;21(1):26–9. Epub 1986/01/01
Clark DA, Thompson JE, Weiner LB, McMillan JA, Schneider AJ, Rokahr JE. Necrotizing enterocolitis: intraluminal biochemistry in human neonates and a rabbit model. Pediatr Res. 1985;19(9):919–21. Epub 1985/09/01
Miller MJ, Adams J, Gu XA, Zhang XJ, Clark DA. Hemodynamic and permeability characteristics of acute experimental necrotizing enterocolitis. Dig Dis Sci. 1990;35(10):1257–64. Epub 1990/10/01
Clark DA, Fornabaio DM, McNeill H, Mullane KM, Caravella SJ, Miller MJ. Contribution of oxygen-derived free radicals to experimental necrotizing enterocolitis. Am J Pathol. 1988;130(3):537–42. Epub 1988/03/01
Bahr R, Flach A. Morphological and functional adaptation after massive resection of the small intestine: experiments using minipigs of the Gottingen strain. Prog Pediatr Surg. 1978;12:107–42. Epub 1978/01/01
Sigalet DL, Lees GM, Aherne F, Van Aerde JE, Fedorak RN, Keelan M, et al. The physiology of adaptation to small bowel resection in the pig: an integrated study of morphological and functional changes. J Pediatr Surg. 1990;25(6):650–7. Epub 1990/06/01
Thompson JS, Quigley EM, Adrian TE. Factors affecting outcome following proximal and distal intestinal resection in the dog: an examination of the relative roles of mucosal adaptation, motility, luminal factors, and enteric peptides. Dig Dis Sci. 1999;44(1):63–74. Epub 1999/02/10
Lansky Z, Dodd RM, Stahlgren LH. Regeneration of the intestinal epithelium after resection of the small intestine in dogs. Am J Surg. 1968;116(1):8–12. Epub 1968/07/01
Cuthbertson EM, Gilfillan RS, Burhenne HJ, Mackby MJ. Massive small bowel resection in the beagle, including laboratory data in severe undernutrition. Surgery. 1970;68(4):698–705. Epub 1970/10/01
Nygaard K. Resection of the small intestine in rats. 3. Morphological changes in the intestinal tract. Acta Chir Scand. 1967;133(3):233–48. Epub 1967/01/01
Dowling RH, Booth CC. Structural and functional changes following small intestinal resection in the rat. Clin Sci. 1967;32(1):139–49. Epub 1967/02/01
Helmrath MA, VanderKolk WE, Can G, Erwin CR, Warner BW. Intestinal adaptation following massive small bowel resection in the mouse. J Am Coll Surg. 1996;183(5):441–9. Epub 1996/11/01
Kim HB, Fauza D, Garza J, Oh JT, Nurko S, Jaksic T. Serial transverse enteroplasty (STEP): a novel bowel lengthening procedure. J Pediatr Surg. 2003;38(3):425–9. Epub 2003/03/13
Chang RW, Javid PJ, Oh JT, Andreoli S, Kim HB, Fauza D, et al. Serial transverse enteroplasty enhances intestinal function in a model of short bowel syndrome. Ann Surg. 2006;243(2):223–8. Epub 2006/01/25
Piper H, Modi BP, Kim HB, Fauza D, Glickman J, Jaksic T. The second STEP: the feasibility of repeat serial transverse enteroplasty. J Pediatr Surg. 2006;41(12):1951–6. Epub 2006/12/13
Dudrick SJ. History of parenteral nutrition. J Am Coll Nutr. 2009;28(3):243–51. Epub 2010/02/13
SJ Dudrick HV, Rawnsley HM. Total intravenous feeding and growth in puppies. Fed Proc. 1966;25:481.
Dudrick SJDW, Vars HM. Long-term parenteral nutrition with growth in puppies and positive nitrogen balance in patients. Surg Forum. 1967;18:356–7.
Dudrick SJ, Wilmore DW, Vars HM, Rhoads JE. Long-term total parenteral nutrition with growth, development, and positive nitrogen balance. Surgery. 1968;64(1):134–42. Epub 1968/07/01
Wilmore DW, Dudrick SJ. Growth and development of an infant receiving all nutrients exclusively by vein. JAMA. 1968;203(10):860–4. Epub 1968/03/04
Abu-Hijleh G, Qi BQ, Williams AK, Beasley SW. Development of the bones and synovial joints in the rat model of the VATER association. J Orthop Sci. 2000;5(4):390–6. Epub 2000/09/12
Beasley SW, Diez Pardo J, Qi BQ, Tovar JA, Xia HM. The contribution of the adriamycin-induced rat model of the VATER association to our understanding of congenital abnormalities and their embryogenesis. Pediatr Surg Int. 2000;16(7):465–72. Epub 2000/11/01
Kotsios C, Merei J, Hutson JM, Graham HK. Skeletal anomalies in the adriamycin-exposed prenatal rat: a model for VATER association. J Orthop Res. 1998;16(1):50–3. Epub 1998/05/09
Merei J, Batiha A, Hani IB, El-Qudah M. Renal anomalies in the VATER animal model. J Pediatr Surg. 2001;36(11):1693–7. Epub 2001/10/31
Merei J, Hasthorpe S, Farmer P, Hutson JM. Visceral anomalies in prenatally adriamycin-exposed rat fetuses: a model for the VATER association. Pediatr Surg Int. 1999;15(1):11–6. Epub 1999/01/23
Merei JM. Single umbilical artery and the VATER-animal model. J Pediatr Surg. 2003;38(12):1756–9. Epub 2003/12/11
Naito Y, Kimura T, Aramaki M, Izumi K, Okada Y, Suzuki H, et al. Caudal regression and tracheoesophageal malformation induced by adriamycin: a novel chick model of VATER association. Pediatr Res. 2009;65(6):607–12. Epub 2009/02/17
Orford JE, Cass DT. Dose response relationship between adriamycin and birth defects in a rat model of VATER association. J Pediatr Surg. 1999;34(3):392–8. Epub 1999/04/22
Sorio C, Moore PS, Ennas MG, Tecchio C, Bonora A, Sartoris S, et al. A novel cell line and xenograft model of ampulla of Vater adenocarcinoma. Virchows Archiv. 2004;444(3):269–77. Epub 2003/12/17
Temelcos C, Hutson JM. Ontogeny of the VATER kidney in a rat model. Anat Rec A Discov Mol Cell Evol Biol. 2004;278(2):520–7. Epub 2004/05/28
Fauza DO. Tissue engineering: current state of clinical application. Curr Opin Pediatr. 2003;15:267–71.
Vacanti JP. Tissue engineering: from bench to bedside via commercialization. Surgery. 2008;143(2):181–3.
Ashizuka S, Peranteau WH, Hayashi S, Flake AW. Busulfan-conditioned bone marrow transplantation results in high-level allogeneic chimerism in mice made tolerant by in utero hematopoietic cell transplantation. Exp Hematol. 2006;34(3):359–68. Epub 2006/03/18
Hayashi S, Peranteau WH, Shaaban AF, Flake AW. Complete allogeneic hematopoietic chimerism achieved by a combined strategy of in utero hematopoietic stem cell transplantation and postnatal donor lymphocyte infusion. Blood. 2002;100(3):804–12. Epub 2002/07/20
Peranteau WH, Hayashi S, Hsieh M, Shaaban AF, Flake AW. High-level allogeneic chimerism achieved by prenatal tolerance induction and postnatal nonmyeloablative bone marrow transplantation. Blood. 2002;100(6):2225–34. Epub 2002/08/30
Peranteau WH, Heaton TE, Gu YC, Volk SW, Bauer TR, Alcorn K, et al. Haploidentical in utero hematopoietic cell transplantation improves phenotype and can induce tolerance for postnatal same-donor transplants in the canine leukocyte adhesion deficiency model. Biol Blood Marrow Transplant. 2009;15(3):293–305. Epub 2009/02/11
Fauza DO, Fishman SJ, Mehegan K, Atala A. Videofetoscopically assisted fetal tissue engineering: skin replacement. J Pediatr Surg. 1998;33(2):357–61. Epub 1998/03/14
Fauza DO, Fishman SJ, Mehegan K, Atala A. Videofetoscopically assisted fetal tissue engineering: bladder augmentation. J Pediatr Surg. 1998;33(1):7–12. Epub 1998/02/24
Fuchs JR, Kaviani A, Oh JT, LaVan D, Udagawa T, Jennings RW, et al. Diaphragmatic reconstruction with autologous tendon engineered from mesenchymal amniocytes. J Pediatr Surg. 2004;39(6):834–8. discussion -8. Epub 2004/06/09
Fuchs JR, Nasseri BA, Vacanti JP, Fauza DO. Postnatal myocardial augmentation with skeletal myoblast-based fetal tissue engineering. Surgery. 2006;140(1):100–7.
Fuchs JR, Terada S, Hannouche D, Ochoa ER, Vacanti JP, Fauza DO. Fetal tissue engineering: chest wall reconstruction. J Pediatr Surg. 2003;38(8):1188–93. Epub 2003/08/02
Fuchs JR, Terada S, Ochoa ER, Vacanti JP, Fauza DO. Fetal tissue engineering: in utero tracheal augmentation in an ovine model. J Pediatr Surg. 2002;37(7):1000–6. discussion -6. Epub 2002/06/22
Kaviani A, Perry TE, Dzakovic A, Jennings RW, Ziegler MM, Fauza DO. The amniotic fluid as a source of cells for fetal tissue engineering. J Pediatr Surg. 2001;36(11):1662–5.
Klein JD, Turner CG, Ahmed A, Steigman SA, Zurakowski D, Fauza DO. Chest wall repair with engineered fetal bone grafts: an efficacy analysis in an autologous leporine model. J Pediatr Surg. 2010;45(6):1354–60. Epub 2010/07/14
Kunisaki SM, Freedman DA, Fauza DO. Fetal tracheal reconstruction with cartilaginous grafts engineered from mesenchymal amniocytes. J Pediatr Surg. 2006;41(4):675–82. discussion -82. Epub 2006/03/29
Kunisaki SM, Fuchs JR, Kaviani A, Oh JT, LaVan DA, Vacanti JP, et al. Diaphragmatic repair through fetal tissue engineering: a comparison between mesenchymal amniocyte- and myoblast-based constructs. J Pediatr Surg. 2006;41(1):34–9. discussion -9. Epub 2006/01/18
Kunisaki SM, Fuchs JR, Steigman SA, Fauza DO. A comparative analysis of cartilage engineered from different perinatal mesenchymal progenitor cells. Tissue Eng. 2007;13(11):2633–44. Epub 2007/07/28
Kunisaki SM, Jennings RW, Fauza DO. Fetal cartilage engineering from amniotic mesenchymal progenitor cells. Stem Cells Dev. 2006;15(2):245–53.
Schmidt D, Achermann J, Odermatt B, Breymann C, Mol A, Genoni M, et al. Prenatally fabricated autologous human living heart valves based on amniotic fluid derived progenitor cells as single cell source. Circulation. 2007;116(11 Suppl):I64–70.
Schmidt D, Mol A, Breymann C, Achermann J, Odermatt B, Gossi M, et al. Living autologous heart valves engineered from human prenatally harvested progenitors. Circulation. 2006;114(1 Suppl):I125–31.
Steigman SA, Ahmed A, Shanti RM, Tuan RS, Valim C, Fauza DO. Sternal repair with bone grafts engineered from amniotic mesenchymal stem cells. J Pediatr Surg. 2009;44(6):1120–6. discussion 6. Epub 2009/06/16
Kunisaki SM, Armant M, Kao GS, Stevenson K, Kim H, Fauza DO. Tissue engineering from human mesenchymal amniocytes: a prelude to clinical trials. J Pediatr Surg. 2007;42(6):974–9. discussion 9–80
Steigman SA, Armant M, Bayer-Zwirello L, Kao GS, Silberstein L, Ritz J, et al. Preclinical regulatory validation of a 3-stage amniotic mesenchymal stem cell manufacturing protocol. J Pediatr Surg. 2008;43(6):1164–9.
Turner CG, Klein JD, Steigman SA, Armant M, Nicksa GA, Zurakowski D, et al. Preclinical regulatory validation of an engineered diaphragmatic tendon made with amniotic mesenchymal stem cells. J Pediatr Surg. 2011;46(1):57–61. Epub 2011/01/18
Fauza DO, Jennings RW, Teng YD, Snyder EY. Neural stem cell delivery to the spinal cord in an ovine model of fetal surgery for spina bifida. Surgery. 2008;144(3):367–73.
Klein JD, Turner CG, Steigman SA, Ahmed A, Zurakowski D, Eriksson E, et al. Amniotic mesenchymal stem cells enhance normal fetal wound healing. Stem Cells Dev. 2011;20(6):969–76. Epub 2010/10/29
Matsumura G, Hibino N, Ikada Y, Kurosawa H, Shin'oka T. Successful application of tissue engineered vascular autografts: clinical experience. Biomaterials. 2003;24(13):2303–8. Epub 2003/04/18
Marcacci M, Kon E, Moukhachev V, Lavroukov A, Kutepov S, Quarto R, et al. Stem cells associated with macroporous bioceramics for long bone repair: 6- to 7-year outcome of a pilot clinical study. Tissue Eng. 2007;13(5):947–55. Epub 2007/05/09
Hibino N, McGillicuddy E, Matsumura G, Ichihara Y, Naito Y, Breuer C, et al. Late-term results of tissue-engineered vascular grafts in humans. J Thorac Cardiovasc Surg. 2010;139(2):431–6. 6 e1–2. Epub 2010/01/29
Shin'oka T, Matsumura G, Hibino N, Naito Y, Watanabe M, Konuma T, et al. Midterm clinical result of tissue-engineered vascular autografts seeded with autologous bone marrow cells. J Thorac Cardiovasc Surg. 2005;129(6):1330–8. Epub 2005/06/09
Shin'oka T, Imai Y, Ikada Y. Transplantation of a tissue-engineered pulmonary artery. N Engl J Med. 2001;344(7):532–3. Epub 2001/02/28
Dionigi B, Ahmed A, Brazzo J 3rd, Connors JP, Zurakowski D, Fauza DO. Partial or complete coverage of experimental spina bifida by simple intra-amniotic injection of concentrated amniotic mesenchymal stem cells. J Pediatr Surg. 2015;50(1):69–73. Epub 2015/01/20
Dionigi B, Brazzo JA 3rd, Ahmed A, Feng C, Wu Y, Zurakowski D, et al. Trans-amniotic stem cell therapy (TRASCET) minimizes Chiari-II malformation in experimental spina bifida. J Pediatr Surg. 2015;50(6):1037–41. Epub 2015/05/02
Feng C, D’Graham C, Connors JP, Brazzo J 3rd, Zurakowski D, Fauza DO. A comparison between placental and amniotic mesenchymal stem cells for transamniotic stem cell therapy (TRASCET) in experimental spina bifida. J Pediatr Surg. 2016;51(6):1010–3.
Feng C, Graham CD, Connors JP, Brazzo J 3rd, Pan AH, Hamilton JR, et al. Transamniotic stem cell therapy (TRASCET) mitigates bowel damage in a model of gastroschisis. J Pediatr Surg. 2016;51(1):56–61. Epub 2015/11/10
Rangel SJ, Kelsey J, Henry MC, Moss RL. Critical analysis of clinical research reporting in pediatric surgery: justifying the need for a new standard. J Pediatr Surg. 2003;38(12):1739–43. Epub 2003/12/11
Abdullah F, Ortega G, Islam S, Barnhart DC, St Peter SD, Lee SL, et al. Outcomes research in pediatric surgery. Part 1: overview and resources. J Pediatr Surg. 2011;46(1):221–5. Epub 2011/01/18
Chang DC, Rhee DS, Papandria D, Aspelund G, Cowles RA, Huang EY, et al. Outcomes research in pediatric surgery. Part 2: how to structure a research question. J Pediatr Surg. 2011;46(1):226–31. Epub 2011/01/18
Moss RL. The CONSORT statement: Progress in clinical research in pediatric surgery. J Pediatr Surg. 2001;36(12):1739–42. Epub 2001/12/06
Polites SF, Habermann EB, Zarroug AE, Wagie AE, Cima RR, Wiskerchen R, et al. A comparison of two quality measurement tools in pediatric surgery—the American College of Surgeons National Surgical Quality Improvement Program-Pediatric versus the Agency for Healthcare Research and Quality Pediatric Quality Indicators. J Pediatr Surg. 2015;50(4):586–90. Epub 2015/04/04
Folkman J. Tumor angiogenesis: therapeutic implications. N Engl J Med. 1971;285(21):1182–6. Epub 1971/11/18
Klagsbrun M, Moses MA. Obituary: M. Judah Folkman (1933–2008). Nature. 2008;451(7180):781. Epub 2008/02/15
Carmeliet P. Angiogenesis in life, disease and medicine. Nature. 2005;438(7070):932–6. Epub 2005/12/16
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer-Verlag London Ltd., part of Springer Nature
About this chapter
Cite this chapter
Turner, C.G., Fauza, D.O. (2018). Research in Pediatric Surgery. In: Losty, P., Flake, A., Rintala, R., Hutson, J., lwai, N. (eds) Rickham's Neonatal Surgery. Springer, London. https://doi.org/10.1007/978-1-4471-4721-3_3
Download citation
DOI: https://doi.org/10.1007/978-1-4471-4721-3_3
Published:
Publisher Name: Springer, London
Print ISBN: 978-1-4471-4720-6
Online ISBN: 978-1-4471-4721-3
eBook Packages: MedicineMedicine (R0)