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1.
Background/Purpose: This study was aimed at characterizing the structure and function of engineered fetal cartilage in vitro. Methods: Chondrocytes from ovine specimens of fetal elastic, fetal hyaline, and adult elastic cartilage were expanded in culture and their growth rates determined. Cells were seeded onto synthetic scaffolds, which were then maintained in a bioreactor. Matrix deposition was determined by specific staining and quantitative assays for glycosaminoglycans (GAG), type II collagen (CII), and elastin, as well as compared with native tissue. Statistical analysis was by analysis of variance (ANOVA) and Students' t test, with significance set at P less than .01. Results: Fetal elastic chondrocytes grew significantly faster than all other cell types. All fetal constructs resembled hyaline cartilage, regardless of the cell source. There were significantly higher levels of GAG and CII in fetal versus adult constructs, but no significant difference between fetal constructs from different sources. Unlike their adult counterparts, fetal constructs had GAG and CII levels similar to native tissues. Conclusions: Fetal chondrocytes can be rapidly expanded in culture. Compared with adult constructs, matrix deposition is enhanced in engineered fetal cartilage, which closely resembles native tissue, regardless of the cell source. Engineered fetal cartilage may be a preferable option during surgical reconstruction of select congenital anomalies.  相似文献   

2.
Purpose: Tissue engineering of the urinary bladder using autologous cells and biodegradable scaffold is a promising method for augmentation. The authors developed 2 hybrid scaffolds by combining poly (DL-lactic-co-glycolic acid; PLGA) mesh for mechanical strength with collagen sponge or gel suitable for cell seeding. The aim of this study was to compare collagen as a scaffold between collagen sponge and gel and to construct a tissue-engineered urinary bladder wall utilizing these hybrid scaffolds.Methods: The PLGA mesh-collagen hybrid scaffolds were prepared by introducing collagen sponge or gel into the PLGA knitted mesh. Urothelial and smooth muscle cells were obtained from porcine urinary bladder wall and were cultured in their respective media. The cells were seeded on these hybrid scaffolds. These constructs were analyzed morphologically and immunohistochemically.Results: The urothelial layer was generated 3 dimensionally by culturing urothelial cells with PLGA mesh and collagen sponge. The smooth muscle layer was constructed by culturing smooth muscle cells with PLGA mesh and collagen gel. And a novel tissue-engineered urinary bladder wall was constructed laminating the urothelial and smooth muscle layers.Conclusions: Ex vivo construction of urinary bladder wall using hybrid scaffolds prepared by combining PLGA mesh with collagen sponge or gel was successful. This tissue-engineered urinary bladder wall allows easy handling and may become a promising tool for bladder augmentation.  相似文献   

3.
Background/Purpose: Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is characterized by decreased or absent peristalsis. Gastrointestinal motility depends on the enteric nervous system, smooth muscle cells (SMCs), and the interstitial cells of Cajal (ICCs). Contractile and cytoskeleton proteinase are important structural and functional components of SMCs. The aim of study was to examine the expression of contractile and cytoskeleton proteins in SMCs and distribution of ICCs in MMIHS bowel. Methods: Full-thickness bowel specimens were obtained from 4 infants with MMIHS and 4 controls. Specimens were processed as whole-mount preparations and frozen and paraffin sections. Combined staining of NADPH-d histochemistry/c-kit immunohistochemistry, single and double immunohistochemistry using [alpha ]-smooth muscle actin ([alpha ]-SMA), calponin (CALP), caldesmon (CALD), desmin (DES), protein gene product 9.5 (PGP 9.5) and c-kit antibodies were performed and examined using light and confocal scanning microscopy. Results: [alpha ]-SMA, CALP, CALD, and DES immunoreactivity were reduced markedly in MMIHS bowel compared with controls. Combined NADPH/c-kit staining showed dense network of ICCs around myenteric plexus in MMIHS bowel. In contrast, the intramuscular ICCs either were absent or reduced in MMIHS bowel. Conclusions: Marked reduction of contractile and cytoskeleton proteins in SMCs combined with reduced expression of intramuscular ICCs in the gut may be responsible for the motility dysfunction in MMIHS. J Pedriatr Surg 38:749-755. [copy ] 2003 Elsevier Inc. All rights reserved.  相似文献   

4.
5.
Purpose: This study was aimed at determining whether fetal tissue constructs can be engineered from cells derived from the placenta. Methods: A subpopulation of morphologically distinct cells was isolated mechanically from specimens of human placenta (n = 6) and selectively expanded. The lineage of these cells was determined by immunofluorescent staining against multiple intermediate filaments and surface antigens. Cell proliferation rates were determined by oxidation assays and compared with those of immunocytochemically identical cells derived from human amniotic fluid samples (n = 6). Statistical analysis was by analysis of variance (ANOVA). After expansion, the cells were seeded onto a polyglycolic acid polymer/poly-4-hydroxybutyrate scaffold. The resulting construct was analyzed by both optical and scanning electron microscopy. Results: The immunocytochemical profile of expanded placental cells was consistent with a nontrophoblastic, mesenchymal origin. Their proliferation rate in culture was not significantly different when compared with mesenchymal fetal cells isolated from human amniotic fluid; however, it was greater than previously reported rates for similar cells obtained from postnatal or adult tissues. Construct analysis showed dense layers of cells firmly attached to the scaffold without evidence of cell death. Conclusions: Subpopulations of nontrophoblastic, mesenchymal cells can be isolated consistently from the human placenta. These cells proliferate as rapidly as fetal mesenchymal amniocytes in vitro and attach firmly to polyglycolic acid scaffolds. The placenta can be a valuable and practical source of cells for the engineering of select fetal tissue constructs. J Pediatr Surg 37:995-999.  相似文献   

6.
Background/Purpose: The authors have described previously the use of engineered fetal cartilage in a large animal model of fetal tracheal repair. This study was aimed at comparing cartilage engineered from bone marrow-derived stromal cells (BMSC) to native and engineered cartilage, in this model.Methods: Ovine BMSC were expanded in vitro, seeded onto biodegradable scaffolds, and maintained in transforming growth factor beta 1 (TGF-β1)-supplemented medium for 3 months (group I). Identical scaffolds were seeded with fetal chondrocytes (group II). All constructs were analyzed in vitro, implanted into fetal tracheas, and harvested after birth for further analysis.Results: There were no differences in survival between the groups. All BMSC-based constructs exhibited chondrogenic differentiation. Matrix analyses in vitro showed that both groups had similar levels of glycosaminoglycans (GAG) and type II collagen (C-II), but lower levels of elastin when compared with native fetal cartilage. Yet, compared with group II, group I had higher levels of GAG, equal levels of C-II, and lower levels of elastin. However, remodeling resulted in no differences between the 2 groups in any of these variables in vivo.Conclusions: The bone marrow may be a useful cell source for cartilage engineering aimed at the surgical repair of severe congenital tracheal anomalies, such as tracheal atresia and agenesis, in utero.  相似文献   

7.
Background/Purpose: The fetal development and anatomy of the muscular structures of the anorectal continence system are unclear. To the pediatric surgeon, these structures are of clinical relevance in reconstructive surgery. The aim of this study was to investigate the fetal development of the anorectal continence organ. Methods: A male fetus (14 weeks postconceptionem) of 114-mm crown-rump length was sectioned serially at 18-[mu ]m intervals. The sections were stained, and relevant contours of the sections were transferred onto paper using a Zeiss Axioskop drawing apparatus. The drawings then were scanned and digitized. Results: Three-dimensional images were created (and animated in a video). These have permitted the demonstration of isolated anatomic structures, the disassembling and reassembling of compound structures, as well as the visualization of structures from different angles. Conclusions: Further studies are now undertaken of older fetal stages through to birth, as well as during postnatal stages. Comparative studies in animals and animations of isolated muscles also are required to show functional capacities. Such studies may lead eventually to an improvement of contemporary surgical techniques. J Pediatr Surg 37:912-915.  相似文献   

8.
Background/Purpose: The management of the fetus with a large neck mass that obstructs the airway remains a clinical challenge. The authors review their experience with giant fetal cervical teratoma and discuss options for management. Methods: A retrospective review of all patients referred since 1994 for prenatal management of a fetal neck mass was performed. Variables examined included gestational age at diagnosis and delivery, size and location of the neck mass, presence of fetal hydrops, associated anomalies, management methods, operating time, and outcome. Results: Seven patients were identified with a prenatal diagnosis of giant cervical teratoma. Four patients had fetal hydrops; of these, 2 died in utero of hydrops, and a third fetus underwent elective termination. The remaining hydropic and previable fetus underwent fetal surgery for resection of the mass. The 3 nonhydropic patients underwent ex utero intrapartum treatment (EXIT) procedures for airway control. Endotracheal intubation was possible in one patient, and one received a tracheostomy. In the third fetus, neither intubation nor tracheostomy were possible, and resection of the neck mass was performed on placental support. There were no deaths in the surgical group. Conclusions: The management of fetal giant cervical teratoma includes a spectrum of options. For the rare previable fetus with hydrops, fetal resection may be indicated. In patients with airway obstruction, EXIT procedure provides the luxury of time to obtain airway control either by intubation, tracheostomy, or, if necessary, tumor resection on placental support. J Pediatr Surg 38:446-450.  相似文献   

9.
Background/Purpose: Development of hydrops fetalis in fetuses with congenital cystic adenomatoid malformations (CCAM) is a significant risk factor for fetal or neonatal demise. In rare cases, resolution of CCAM has occurred, presumably owing to lesion maturation or involution. Steroid therapy, utilized for lung maturity, has been postulated to accelerate this process. The natural history of hydropic fetuses with CCAM after receiving steroid therapy is presented. Methods: The authors prospectively followed up with 3 patients who had antenatally diagnosed CCAM and nonimmune hydrops fetalis with predicted mortality. All patients declined or were not candidates for fetal intervention and were treated with standard prenatal betamethasone to increase lung maturity. Results: Three fetuses had CCAM and nonimmune hydrops fetalis diagnosed prenatally. After a course of prenatal steroids during the second trimester, all 3 patients had resolution of their hydrops and were delivered at term without respiratory distress. Conclusions: Nonimmune hydrops fetalis in fetuses with congenital cystic adenomatoid malformation is a harbinger for fetal demise. The resolution of hydrops in these patients after receiving steroid therapy is an interesting and compelling observation. Because the mechanism of this process is speculative, further studies are needed to elucidate the relationship between antenatal steroids and maturation of congenital cystic adenomatoid malformation. J Pediatr Surg 38:508-510.  相似文献   

10.
Background/Purpose: Extracellular matrix proteins are implicated in regulating cell proliferation and differentiation. The authors systematically analysed the expression of elastin; collagen types I, III, IV; laminin; and fibronectin during mouse detrusor muscle development, a period during which downregulation of detrusor proliferation and increasing smooth muscle differentiation is known to occur. Methods: Embryonic days 14 (E14) and 18 (E18), and postnatal day 1 (D1) and week 6 (6wk) were examined, a period spanning the inception of the bladder to postnatal maturity. Immunohistochemistry of whole bladders was used to immunolocalise protein expression, and Western blot of dissected detrusor layers was used to semiquantify soluble protein expression. Results: All proteins were detected at all 4 stages. Statistically significant increases were documented for elastin (E14 to 6wk), collagen type I (E18 to 6wk), collagen type III (D1 to 6wk) and laminin (E14 to 6wk). Fibronectin levels were relatively high up to D1, after which levels declined significantly. Collagen type IV levels decreased significantly (E18 to 6wk). Conclusions: The authors postulate that changing levels of laminin and fibronectin have opposing effects on the transition from proliferating primitive mesenchymal cells to differentiated detrusor muscle. Furthermore, changes in collagen type III and elastin may be important for bladder compliance. J Pediatr Surg 38:1-12.  相似文献   

11.
Purpose: It was still unclear how urinary tract obstruction alters normal nephrogenesis and leads to renal dysplasia. The authors created an obstructive uropathy model in fetal lambs and reviewed the pathology of the obstructed kidney to determine the optimal timing for decompression of the obstruction.Methods: Obstructive uropathy was created in fetal lambs at 60 days’ gestation by ligating the urethra and urachus. They were delivered 20 to 31 days later by cesarian section. The kidneys were processed for histologic examination.Results: Thirty-four 60-day lambs were operated on. Dysplastic changes were noted in 25 fetuses, and 24 fetuses had cysts in the nephrogenic zone. The cystic components in multicystic dysplastic kidneys (MCDK) are mainly in the proximal tubules.Conclusions: In utero urinary tract obstruction causes reduction of numbers of functioning nephrons and produces cysts in the nephrogenic zone and in the deeper cortex. These cysts and dilated proximal tubules suppress new nephron formation. Twenty days after obstruction, there were early features of dysplasia, but the nephrogenic zones still were present. Early shunting may salvage renal function.  相似文献   

12.
Background: The existence, development, and function of the rectovaginal fascia has been discussed in literature. In women, a defect in the fascia leads to rectoceles and severe constipation. In pediatric textbooks for anorectal or urogenital surgery, however, it is not mentioned. Does the fascia exist in children? Methods: The pelvises of 31 female and, as controls, 31 male fetuses (age from 9 weeks of gestation to newborn) were plastinated. Sections (transversal, sagittal, and frontal) were stained with azure II/ methylenblue/ basic fuchsin and viewed at a magnification of 6.5[times ] to 80[times ]. In addition, the authors investigated macroscopically and microscopically the rectovaginal fascia in 1 fetal and 1 adult cadaver. Results: At the beginning of the fetal period the authors recognized the anlage of the rectovaginal fascia caudal from the rectouterine excavation. Later, a fascia of connective tissue develops. It is connected directly to areolar connective tissue at the dorsal wall of the vagina. Neurovascular bundles are situated ventrolaterally of the rectal wall. At the level of the anorectal flexure this fascia separates the rectum and the vagina. Conclusions: Our investigations indicate that the rectovaginal fascia is completely developed in newborns, through differentiation of mesenchyme, which develops into a fascia. It protects different compartments and serves as an abutment to the rectal wall. Thus, it is important for adequate bowel emptying. For the surgeon it is a leading structure for preventing nerve damage of the autonomic nerve supply of the pelvic organs. It should be known, protected, and, if necessary, reconstructed.  相似文献   

13.
Background/Purpose: This study was aimed at comparing fetal tissue engineering with autologous free grafting in an ovine model of in utero tracheal repair. Methods: Chondrocytes were isolated from both elastic and hyaline cartilage specimens harvested from fetal lambs and expanded in vitro. Cells were seeded dynamically onto biodegradable scaffolds, which then were maintained in a rotating bioreactor for 6 to 8 weeks. Constructs subsequently were implanted into fetal tracheas (n = 15), in a heterologous fashion (group I). In group II, fetuses (n = 5) received autologous free grafts of elastic cartilage harvested from the ear as tracheal implants. In vivo specimens were harvested for histologic analysis at different time-points postimplantation. Results: In the 12 of 15 surviving fetuses of group I, all constructs were found to resemble normal hyaline cartilage, engraft well despite their heterologous origin, and display time-dependent epithelialization derived from the native trachea. All autologous free grafts were engrafted and epithelialized at birth, retaining histologic characteristics of elastic cartilage, but were more deformed than engineered constructs. Of the lambs allowed to reach term, 5 of 5 in the engineered group and 4 of 5 in the free graft group could breathe spontaneously. Conclusions: (1) Tissue-engineered cartilage, as well as autologous free grafts, can be implanted successfully into the fetal trachea, resulting in engraftment and function. (2) Engineered cartilage provides enhanced structural support after implantation into the fetal trachea when compared with free grafts. Prenatal tracheoplasty may prove useful for the treatment of severe congenital tracheal malformations. J Pediatr Surg 37:1000-1006.  相似文献   

14.
Background/Purpose: This study was aimed at examining the feasibility of fetal tracheal occlusion guided exclusively by ultrasonography and at establishing the technical principles of this procedure based on current instrumentation and ultrasound technology. Methods: Time-dated pregnant ewes underwent a small laparotomy and partial uterine exposure. Under real-time ultrasound guidance, a steerable guide wire was fed into the fetal tracheal lumen. An 8F catheter then was fed around the guide wire into the trachea. This was followed by intratracheal placement of a 2F coaxial angiographic catheter, connected to a detachable silicone balloon at its extremity, which then was inflated with saline and delivered locally. Euthanasia was performed at term. Results: Complete tracheal occlusion was achieved in all fetuses (n = 7) intraoperatively. Operating time needed for tracheal occlusion, once access to the amniotic cavity was established, varied widely, but could be as short 1 minute. Tracheal lumen dimensions outgrew balloon diameter in 57.1% of fetuses (4 of 7), resulting in balloon dislodgment in those animals. No balloon rupture was observed. Conclusions: (1) Accurate access to the fetal trachea and local delivery of an occlusive detachable silicone balloon are consistently feasible exclusively under real-time ultrasound guidance with commercially available instrumentation. (2) Balloon dimensions are determining factors of displacement risk and must be selected carefully before tracheal delivery. Ultrasound-guided fetal tracheal occlusion may be a preferable alternative to surgical intervention for treatment of fetal pulmonary hypoplasia.  相似文献   

15.
Purpose: Fetal surgery is performed increasingly with minimal access approaches. The authors report their experience with fetal endoscopic procedures (fetendo) with emphasis on changing techniques and outcome trends. Methods: All fetal endoscopic cases performed at a single institution from January 1996 to August 2001 were reviewed (n = 66). Cases were examined with respect to year performed, type of operation, operative data, and outcome. Results: Twin-twin transfusion syndrome (26 cases) and congenital diaphragmatic hernia (35 cases) were the most common diseases treated. From 1996 to 2001, there was a decrease in average operating time (256 to 127 minutes [P = .0006]), number of ports utilized (3.8 to one [P = .00001]), pump volume (28.7 to 2.7 L [P = .00001]), and estimated blood loss (408 to 29 mL [P = .008]). In addition, port size changed from 10 mm to 5 mm. Chorioamniotic separation (31 of 66), premature rupture of membranes (32 of 66), chorioamnionitis (12 of 66), and fetal death (10 of 66) continued to be significant complications. Conclusions: Fetal endoscopic surgery over the last 6 years has evolved toward shorter operating time, the use of smaller and fewer ports, decreased pump fluid exchange, and decreased blood loss, with the types of cases centered on twin-twin transfusion syndrome and congenital diaphragmatic hernia.  相似文献   

16.
Purpose: The aim of this work was to study amniotic fluid [beta ]-endorphin as a potential predictor for postnatal morbidity in gastroschisis. Methods: Beta-endorphin was assayed in 43 amniotic fluid samples from 13 pregnant women with fetal gastroschisis undergoing diagnostic amniocentesis or therapeutic amnioinfusion and compared with 33 controls. Within the gastroschisis group, the authors investigated the relationship between postnatal morbidity and the peak value of amniotic fluid [beta ]-endorphin (AFBE). Results: Ten AFBE values in 6 cases of gastroschisis were above the upper limit of the 95% confidence interval derived from controls. Postnatal morbidity was significantly higher when peak AFBE exceeded 10 [mu ]g/L (n = 4 pregnancies) compared with below 5 [mu ]g/L (n = 9 pregnancies), as shown by mean duration of mechanical ventilation (15.2 v 3 days; P = .01), of parenteral feeding (77 v. 18.7 days; P = .04), and of hospitalization (84 v 32.2 days; P = .04). There was no statistically significant association between postnatal morbidity markers and prenatal dilation of fetal bowel. Conclusions: The most severe cases of gastroschisis are associated with high levels of AFBE. The authors speculate that this fetal hormonal response could result from stress or pain caused by prenatal bowel damage.  相似文献   

17.
Background/Purpose: Microgastria and postgastrectomy morbidities are substantial. The authors hypothesized a functional living tissue-engineered stomach could function as a replacement alternative.Methods: Stomach organoid units, mesenchymal cores surrounded by epithelia, were isolated from neonatal and adult rats and transplanted paratopically on biodegradable polymer tubes, which were implanted in syngeneic hosts, varying the inclusion of stomach regions. Four weeks later, tissue-engineered stomach (TES) was either harvested or anastomosed. GFP labeling was performed before implantation. Histology and immunohistochemical detection of the antigensgastrin and actin smooth muscle were performed.Results: Ninety-eight percent of all animals generated TES, including TES formation from adult tissue. Immunohistochemistry for α-actin smooth muscle and gastrin confirms the presence of a smooth muscle layer and a well-developed gastric epithelium containing all the elements of the native rat stomach including gastric pits and squamous layers, varying by included regions at harvest. TES architecture was maintained in anastomosis: GFP-labeled TES maintained signal in anastomosis, proving the donor origin of the TES.Conclusions: TES resembles native stomach and maintains robust histology in anastomosis, a new versatile model for the study of gastric physiology and possible therapy.  相似文献   

18.
Purpose: Interstitial cells of Cajal (ICCs) are pacemaker cells that play an important role in the control of gut motility. Carbon monoxide (CO) has been proposed as an endogenous messenger molecule between ICC and smooth muscle cells in the gastrointestinal tract (GIT). Heme oxygenase-2 (HO-2) is the main physiologic mechanism for generating CO in human cells. The aim of this study was to investigate the immunocolocalization of the HO-2 and ICCs in normal and aganglionic bowel of Hirschsprung's disease (HD). Methods: Full-thickness specimens were obtained from aganglionic colon during pull-through operation from 10 patients diagnosed as having HD. Normal control large bowel specimens were collected from 4 patients during bladder augmentation procedures. Double immunostaining was carried out using c-kit and HO-2 antibodies. Immunolocalization was detected by means of confocal laser scanning microscopy. Results: HO-2 immunoreactivity (IR) was found in many ICCs present around the myenteric plexus, within the longitudinal and circular muscle layers and at the innermost part of the circular muscle layer in normal colon. In the aganglionic colon there was absence of HO-2 IR in the sparsely found ICCs. In the transitional zone of HD bowel the colocalization of HO-2 IR and ICCs was much reduced compared with controls. Conclusions: The results of this study provide the first evidence for the presence of HO-2 immunoreactivity in the ICCs in normal human colon and absence of HO-2 immunoreactivity in sparsely appearing ICCs in the bowel of HD patients. The lack of HO-2 in the ICCs in the bowel of HD patients may result in impaired intracellular communication between ICCs and SMCs causing motility dysfunction. J Pediatr Surg 38:73-77.  相似文献   

19.
Background/purpose: This study was aimed at examining the impact of different tissue engineering techniques on fetal muscle construct architecture.Methods: Myoblasts from ovine specimens of fetal skeletal muscle were expanded in culture and their growth rates determined. Cells were seeded at different densities onto 3 scaffold types, namely polyglycolic acid (PGA) treated with poly-l-lactic acid (PLLA), a composite of PGA with poly-4-hydroxybutyrate (P4HB), and a collagen hydrogel. Constructs were maintained in a bioreactor and submitted to histologic, scanning electron microscopy, and DNA analyses at different time-points. Statistical analysis was by the likelihood ratio and paired Student’s t tests (P < .05).Results: Fetal myoblasts proliferated at faster rates than expected from neonatal cells. Cell attachment was enhanced in the PGA/PLLA matrix and collagen hydrogel when compared with the PGA/P4HB composite. Necrosis was observed at the center of all constructs, directly proportional to cell seeding density and time in the bioreactor.Conclusions: Fetal myoblasts can be expanded rapidly in culture and attach well to PGA/PLLA, as well as collagen hydrogel but less optimally to PGA/P4HB. Excessive cell seeding density and bioreactor time may worsen final construct architecture. These findings should be considered during in vivo trials of muscle replacement by engineered fetal constructs.  相似文献   

20.
Background/Purpose: This study demonstrates a minimally invasive technique for upper esophageal coin extraction. Methods: A retrospective review was conducted of 36 children who had upper esophageal coins extracted using a Magill forceps. Results: All coins were removed without complication in approximately 45 seconds (33 on the first attempt, 3 on the second attempt). Conclusions: This technique minimizes instrumentation of the esophagus and is highly successful at removing coins lodged at or immediately below the level of the cricipharyngeus muscle. J Pediatr Surg 38:227-229.  相似文献   

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