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Biomedical subjects

Timothy M Crombleholme

Publications and source records attributed to Timothy M Crombleholme.

At least 37 records · Page 2Linked to original sources
PubMed2003

In utero limb salvage: fetoscopic release of amniotic bands for threatened limb amputation.

The natural history of extremity amniotic band syndrome (ABS) is a progression to deformity or amputation. Fetoscopic laser release of amniotic bands in extremity ABS offers the potential to prevent limb amputation. The authors report on 2 patients with isolated extremity ABS who underwent fetoscopic release. Both patients had isolated extremity ABS with compromised extremity perfusion and no other significant structural abnormality diagnosed sonographically. The first patient underwent fetoscopic release of bands of the left wrist, and the second patient underwent lysis of bands around the right wrist and an unsuspected band around the right lower extremity. Both patients had restoration of blood flow by color Doppler to the affected extremity. There were no perioperative complications. In select patients with isolated extremity ABS, early fetoscopic release may prevent amputation and allow improved limb development.

Adult↗
PubMed2003

Congenital high airway obstruction syndrome: natural history and management.

BACKGROUND: Congenital high airway obstruction syndrome (CHAOS) is a life-threatening condition with a poorly understood natural history. METHODS: A retrospective review of five patients with CHAOS between 1997 and 2002 was performed. RESULTS: All fetuses had large echogenic lungs, dilated airways, inverted diaphragms, and massive ascites. One fetus with a laryngeal cyst was terminated at 22 weeks. A twin fetus with findings suggestive of a tracheal web had progressive hydrops, which led to fetal demise. The remaining 3 patients delivered via the ex utero intrapartum treatment (EXIT) procedure survived. The first patient tolerated progressive hydrops for 12 weeks in utero. He had tracheal atresia but underwent laryngotracheoplasty successfully. He is the first long-term CHAOS survivor and is speaking at 5 years of age. The 2 patients with relatively stable lung volumes prenatally have laryngeal atresia with a pinpoint posterior laryngeal fistula. Their postnatal clinical courses were much more benign than the first survivor. CONCLUSIONS: The prenatal natural history and postnatal course of CHAOS depends on whether the airway obstruction is complete. The EXIT procedure offers the potential for salvage of this otherwise lethal condition. Hydrops may be well tolerated prenatally for weeks with potential resolution if airway fistulization is present.

Abortion, Eugenic↗
PubMed2003

The treatment of twin-twin transfusion syndrome.

The twin-twin transfusion syndrome (TTTS) is the most common serious complication of monochorionic twin gestations, affecting between 4% and 35% of monochorionic twin pregnancies each year in the United States. The TTTS accounts for 17% of all perinatal mortality associated with twin gestations. Standard therapy in the United States has most commonly been serial amnioreduction, which appears to improve the overall outcome. Intertwin microseptostomy similarly improves outcome but has no survival advantage over serial amnioreduction. Survivors of TTTS treated by serial amnioreduction have an 18% to 26% incidence of sonographically detectable brain abnormalities. Selective fetoscopic laser photocoagulation of chorioangiopagus has emerged as an alternative treatment strategy in TTTS with at least comparable if not superior survival to serial amnioreduction. The superiority of fetoscopic laser treatment of TTTS remains unproven and is the subject of a National Institutes of Health (NIH)-sponsored prospective randomized clinical trial comparing aggressive serial amnioreduction with selective fetoscopic laser photocoagulation for severe TTTS.

Amnion↗
PubMed2003

Stroma formation and angiogenesis by overexpression of growth factors, cytokines, and proteolytic enzymes in human skin grafted to SCID mice.

Reorganization of skin during wound healing, inflammatory disorders, or cancer growth is the result of expression changes of multiple genes associated with tissue morphogenesis. We wanted to identify proteins involved in skin remodeling and select those that may be targeted for agonistic or antagonist therapeutic approaches in various disease processes. Full-thickness human skin was grafted to severe combined immunodeficient mice and injected intradermally with 38 different adenoviral vectors inserted with 37 different genes coding for growth factors, cytokines, proteolytic enzymes and their inhibitors, adhesion receptors, oncogenes, and tumor suppressor genes. Responses were characterized for infiltration of inflammatory cells, vascular density, matrix formation, fibroblast-like cell proliferation, and epidermal hyperplasia. Of the 17 growth factor vectors, 16 induced histological changes in human skin. Members of the VEGF and angiopoietin families induced neovascularization. PDGFs and TGF-betas stimulated connective tissue formation, and the chemokines IL-8 and MCP-1 attracted inflammatory neutrophils and monocytes, respectively. The serine protease uPA induced a vascular response similar to that of VEGF. Vectors with adhesion receptors, oncogenes and tumor suppressor genes had, with few exceptions, little effects on skin architecture. The overall results suggest that adenoviral vectors can effectively remodel the architecture of human skin for studies in morphogenesis, inflammatory skin disorders, wound healing, and cancer development.

Adenoviridae↗
PubMed2003

Management of congenital lung lesions.

The prenatal diagnostic hallmarks, natural history, and management of congenital cystic adenomatoid malformation of the lung and pulmonary sequestration are reviewed. Large lung tumors may disappear partially on serial prenatal sonography, suggesting that improvement can occur occasionally during fetal life. The fetus with a lung mass but without hydrops has an excellent chance for survival with maternal transport, planned delivery, and postnatal evaluation and surgery. The finding that fetuses with hydrops are at very high risk for fetal or neonatal death has led to successful fetal thoracoamniotic shunt placement or fetal surgical resection.

Bronchopulmonary Sequestration↗
PubMed2003

Fetal myelomeningocele repair: short-term clinical outcomes.

OBJECTIVE: The study was undertaken to evaluate short-term clinical outcomes with antenatal myelomeningocele (MMC) repair. STUDY DESIGN: Retrospective review of 50 fetuses that underwent open fetal MMC closure was performed. Inclusion criteria included less than 26 weeks' gestation, thoracic to S1 level defect, absent clubfoot deformity, Arnold-Chiari malformation, ventriculomegaly less than 17 mm, normal karyotype, and no other anomalies. RESULTS: Perinatal survival was 94% (47/50 fetuses). Mean age at delivery was 34 weeks 3 days. All fetuses demonstrated reversal of hindbrain herniation. Forty-three percent of the 50 fetuses have required ventriculoperitoneal shunting compared with 100% thoracic, 88% lumbar, and 68% sacral (85% overall) in 297 historic controls. Better-than-predicted leg function was seen in 57% of thoracic and lumbar level lesion patients. CONCLUSION: Early experience with fetal MMC repair suggests a decreased need for ventriculoperitoneal shunting, arrest or slowing of progressive ventriculomegaly, and consistent resolution of hindbrain herniation. However, further long-term follow-up is needed to evaluate neurodevelopment and bladder and bowel function.

Adult↗
PubMed2003

Fetoscopic surgery.

Explore the source record for details and available documents.

Diseases in Twins↗
PubMed2003

Regenerative versus reparative healing in tendon: a study of biomechanical and histological properties in fetal sheep.

Previous studies have shown fetal tissues heal in a regenerative fashion without scar formation. The objective of this study is to compare the healing properties of adult and fetal tendons. Time-mated pregnant ewes at 80-85 days of gestation were utilized. A partial, midsubstance tenotomy was performed in the lateral extensor fetal tendons, and analogous tenotomies were created in the maternal limbs. One week after injury, the fetal and adult animals were sacrificed, and tendons were histologically and mechanically evaluated. Immunohistochemical staining for transforming growth factor beta isoform 1 (TGF-beta1) was performed. Histologically, a gap with granulation tissue and inflammatory cells was visible in the site of wounding in the adult tendons. In the fetal tendons, no abnormalities were noted in the wound, with reconstitution of collagen architecture. TGF-beta1 expression was low in fetal but upregulated in the adult wounds. No significant differences were found in the biomechanical properties between groups. We identified regenerative healing properties in injured fetal tendon, while adult tendon tissue healed reparatively with scar formation. Fetal tendons demonstrated a limited recovery of mechanical properties after injury that was no better than that of the adult tendons at seven days. A better understanding of the mechanisms of fetal healing may lead to novel therapeutic strategies in the clinical setting.

Aging↗
PubMed2002

The natural history of prenatally diagnosed conjoined twins.

BACKGROUND/PURPOSE: Accurate prenatal diagnosis of complex anatomic connections and associated anomalies has only been possible recently with the use of ultrasonography, echocardiography, and fetal magnetic resonance imaging (MRI). To assess the impact of improved antenatal diagnosis in the management and outcome of conjoined twins, the authors reviewed their experience with 14 cases. METHODS: A retrospective review of prenatally diagnosed conjoined twins referred to our institution from 1996 to present was conducted. RESULTS: In 14 sets of conjoined twins, there were 10 thoracoomphalopagus, 2 dicephalus tribrachius dipus, 1 ischiopagus, and 1 ischioomphalopagus. The earliest age at diagnosis was 9 weeks' gestation (range, 9 to 29; mean, 20). Prenatal imaging with ultrasonography, echocardiography, and ultrafast fetal MRI accurately defined the shared anatomy in all cases. Associated anomalies included cardiac malformations (11 of 14), congenital diaphragmatic hernia (4 of 14), abdominal wall defects (2 of 14), and imperforate anus (2 of 14). Three sets of twins underwent therapeutic abortion, 1 set of twins died in utero, and 10 were delivered via cesarean section at a mean gestational age of 34 weeks. There were 5 individual survivors in the series after separation (18%). In one case, in which a twin with a normal heart perfused the cotwin with a rudimentary heart, the ex utero intrapartum treatment procedure (EXIT) was utilized because of concern that the normal twin would suffer immediate cardiac decompensation at birth. This EXIT-to-separation strategy allowed prompt control of the airway and circulation before clamping the umbilical cord and optimized control over a potentially emergent situation, leading to survival of the normal cotwin. In 2 sets of twins in which each twin had a normal heart, tissue expanders were inserted before separation. CONCLUSIONS: Advances in prenatal diagnosis allow detailed, accurate evaluations of conjoined twins. Careful prenatal studies may uncover cases in which emergent separation at birth is lifesaving.

Female↗
PubMed2002

Cystic adenomatoid malformation volume ratio predicts outcome in prenatally diagnosed cystic adenomatoid malformation of the lung.

BACKGROUND/PURPOSE: Cystic adenomatoid malformation of the lung (CAM) diagnosed in utero has a variable natural history that may result in hydrops in up to 40% or regress in up to 15%. No criteria have been available to determine which lesions would grow and develop hydrops versus those whose growth would stabilize or regress. To better understand the natural history of CAM the authors developed a measure of tumor volume normalized for gestation age, the CAM volume ratio, or CVR. The results of an initial retrospective review of CVR at presentation suggested its usefulness as a predictor of outcome in CAM. The authors now report the results of prospective use of the CVR both to track tumor growth and regression during gestation and confirm its predictive value in fetuses with CAM. METHODS: In the retrospective review performed between November 1998 and August 1999, 32 fetuses with CAM were reviewed and divided into those with hydrops and those in whom hydrops never developed. The CVR was determined by measuring 3 dimensions of the CAM using the formula for the volume of an ellipse and dividing by the head circumference to correct for differences in gestational age. Of the 32 fetuses in the retrospective study, the 8 that had hydrops had a significantly higher CVR (3.1 plus minus 1.1) compared with hydropic fetuses (0.74 plus minus 0.48; P <.001). The mean of the nonhydropic fetus's CVR plus 2 standard deviations (0.74 + 0.96 = 1.7) was used as a cutoff in the subsequent prospective study. From September 1, 1999 through March 1, 2001, the authors evaluated prospectively 58 patients with CAM by CVR measurement. These patients were followed up with serial ultrasound scans, and CVR at presentation correlated with the development of hydrops, survival, need for fetal intervention, and the need for ventilatory support or extracorporeal membrane oxygenation (ECMO), and length of hospital stay postnatally. The indication for fetal intervention was the development of hydops. RESULTS: The fetuses with CVR less-than-or-equal1.6 (n = 42) were considered to be at low risk for the development of hydrops, and those with CVR greater than 1.6 (n = 16) were considered at increased risk for developing hydrops. Of the 42 fetuses in the low-risk group, 7 (16.7%) developed hydrops, and all but 1 had a dominant cyst. If CAMs with a dominant cyst are excluded, only 1 of 36 (2.8%) of CAMs with CVR less-than-or-equal 1.6 developed hydrops (P <.001). In fetuses with CVR at presentation more than 1.6, 12 of 16 (75%; P <.005) developed hydrops. Seventeen fetuses underwent fetal treatment (8 CVR less-than-or-equal 1.6; 9 CVR > 1.6): 7 patients required open fetal surgery (survival rate, 2 of 7), 6 patients thoracoamniotic shunting (survival rate, 6 of 6); and 4 patients cyst aspiration (survival rate, 4 of 4). All survivors of fetal intervention required at a least brief period of ventilatory support; none required ECMO. CONCLUSIONS: A CVR of greater than 1.6 at presentation accurately predicts increased risk of hydrops developing in CAM. A CVR of less-than-or-equal1.6 at presentation suggests that the risk of hydrops developing in the absence of a dominant cyst is less than 3%. The CVR is a useful sonographic indicator of fetuses at risk for hydrops who require close ultrasound observation and possible fetal intervention.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed2002

The EXIT procedure: experience and outcome in 31 cases.

BACKGROUND: The EXIT (ex utero intrapartum treatment) procedure, although initially designed for reversal of tracheal occlusion in fetuses with congenital diaphragmatic hernias (CDH), has been adapted to treat a variety of fetal conditions. METHODS: A retrospective chart review of all consecutive EXIT procedures since 1996 was conducted. RESULTS: Thirty-one women underwent the EXIT procedure, with an average maternal age of 29 years (range, 20 to 38), and average gestational age of 34 weeks (range, 29 to 40). The indication was airway obstruction from fetal neck mass in 13, and reversal of tracheal occlusion from in utero clipping in 13. Singular indications included an EXIT-to-ECMO (extracorporeal membrane oxygenation) procedure for a fetus with CDH and a cardiac defect (n = 1), congenital high airway obstruction syndrome (CHAOS, n = 1), resection of a very large congenital cystic adenomatoid malformation of the lung (CCAM) on uteroplacental bypass (n = 1), unilateral pulmonary agenesis (n = 1), and thoracoomphalopagus conjoined twins. The mean duration on uteroplacental bypass (from uterine incision to umbilical cord clamping) was 30.3 plus minus 14.7 minutes (range, 8 to 66). No fetus experienced hemodynamic instability during uteroplacental bypass as recorded by fetal heart rate (FHR), pulse oximeter, and fetal echocardiography, except for one instance of reversible bradycardia from umbilical cord compression. The mean FHR and fetal saturation were 153.0 plus minus 38.5 beats per minute and 71.2% plus minus 19.9%, respectively. Five fetuses required a tracheostomy. Only 1 death occurred during an EXIT procedure because of inability to secure the airway secondary to extensive involvement by a lymphangioma. The average cord pH and pCO(2) were, respectively, 7.20 plus minus 0.11 and 63.2 plus minus 14.6. Two maternal complications occurred: bleeding from a hysterotomy site and dehiscence of an old hysterotomy scar noticed at a subsequent cesarean section. The average maternal blood loss was 848.3 plus minus 574.1 mL. CONCLUSION: The EXIT procedure was used successfully to ensure uteroplacental gas exchange and fetal hemodynamic stability during a variety of surgical procedures performed to secure the fetal airway or ensure successful transition to postnatal environment.

Adult↗
PubMed2002

Adeno-associated virus (AAV)-mediated gene transfer in respiratory epithelium and submucosal gland cells in human fetal tracheal organ culture.

BACKGROUND/PURPOSE: Since the discovery of the cystic fibrosis transmembrane regulator (CFTR) gene, cystic fibrosis has been an attractive target for gene therapy. Postnatal gene transfer in the respiratory epithelium has been difficult and particularly inefficient in the submucosal gland cells, the target cells for CFTR gene transfer. The authors hypothesized that during development, there is a favorable environment for fetal gene therapy with fewer physical barriers to efficient gene transfer and more accessible epithelial and submucosal gland precursor cells. The authors tested this hypothesis in a novel human fetal tracheal organ culture system using a serotype 2 recombinant AAV that contains an enhanced green fluorescent protein (eGFP) reporter gene (AAV-CMV-eGFP). METHODS: Human fetal tracheas at between 16 and 20 weeks' gestation age were used in this study. The distal end of each trachea was ligated and secured in an upright position with the open proximal end facing up. Only the ante-lumenal surface was exposed to culture media. 5 x 10(9) particles of AAV-CMV-eGFP were administered intratracheally through the open end. Fetal tracheas were maintained in tracheal organ culture media and harvested at either 2 weeks (n = 3) or 4 weeks (n = 7) after injection. The fetal tracheas were processed for routine H&E, standard electron microscopy (EM), and fluorescence microscopy for analysis of eGFP transgene expression. RESULTS: Histology confirmed the preservation of structural integrity out to 4 weeks of fetal tracheal organ culture. EM showed intact tight junctions of the apical respiratory epithelium. At 2 weeks after AAV-CMV-eGFP injection, there was minimal transgene expression. However, at 4 weeks there was extensive transgene expression in not only the respiratory surface epithelium but also the submucosal gland cells of the human fetal tracheal organ culture. Transgene expression was seen in nearly all cells in the submucosal glands. CONCLUSIONS: AAV-mediated gene transfer in human fetal tracheal organ culture was highly efficient with excellent transgene expression at 4 weeks in both respiratory surface epithelium and submucosal gland cells. This highly efficient gene transfer may result from fewer physical barriers and more accessible target precursor cells. These results are consistent with more efficient gene transfer in fetal tracheobronchial epithelium and show the potential for fetal gene therapy using AAV for the treatment of congenital airway disease such as cystic fibrosis.

Dependovirus↗
PubMed2002

Influence of congenital heart disease on survival in children with congenital diaphragmatic hernia.

OBJECTIVE: We sought to assess outcome in patients with CDH and HD to determine if LHR is also predictive of outcome in this subset of patients. STUDY DESIGN: We carried out a retrospective review (April 1996-October 2000) of patients with isolated CDH (n = 143, 82.2%) and patients with HD (n = 31, 17.8%) to determine the incidence of additional anomalies, survival to term, CDH repair, cardiac repair, and survival to discharge. Survival based on LHR was analyzed in a subset of fetuses. RESULTS: The risk of death from birth to last follow-up was 2.9 times higher for patients with CDH plus HD than for patients with CDH alone (P <.0001). Of 11 patients with CDH plus HD who had CDH repair (5 of whom also had HD repair), 5 survived. All 10 patients with an LHR <1.2 died; 3 of 6 with an LHR >1.2 survived (Fisher exact test, P =.04). CONCLUSION: Heart disease remains a significant risk factor for death in infants with CDH. The LHR helps predict survival in this high-risk group of patients.

Abnormalities, Multiple↗
PubMed2002

The ex-utero intrapartum treatment.

Advances in prenatal diagnosis, combined with a better understanding of the natural history of prenatally diagnosed anomalies, are providing increasing opportunities to consider fetal intervention in selected cases of life-threatening malformations. Accurate prenatal diagnosis can now accurately identify fetal pathophysiology that poses an immediate threat to the life of the newborn infant on separation from the placental circulation. In this circumstance, the ex-utero intrapartum treatment (EXIT) procedure, which maintains intrapartum uteroplacental support, can be life saving. The most common indications for the EXIT procedure are fetal lesions causing extrinsic or intrinsic airway obstruction. However, fetuses with other anomalies that may compromise neonatal resuscitation can also benefit from this approach. The EXIT procedure differs significantly from a cesarean delivery, and caution must be taken to avoid maternal morbidity. As with all endeavors involving maternal-fetal intervention, a team approach is crucial to ensure accurate diagnosis and optimal perinatal management.

Female↗
PubMed2002

Adenovirus-mediated ex vivo gene transfer of human vascular endothelial growth factor in a rabbit laryngotracheal reconstruction model.

Free autologous cartilage, which is used in laryngotracheal reconstruction (LTR), may undergo progressive necrosis as a result of delayed revascularization. Angiogenic growth factors, such as vascular endothelial growth factor (VEGF), promote angiogenesis in the ischemic environment. We studied the effect of ex vivo gene transfer of VEGF121 on cartilage angiogenesis and graft survival in a rabbit model of LTR. Sixty rabbits underwent LTR with auricular cartilage. The grafts were treated at 1 x 10(9) plaque-forming units with 1) VEGF121 (n = 20), 2) LacZ reporter gene (n = 20), or 3) saline solution (n = 20). Graft neovascularization and survival were histologically assayed at 1 and 10 weeks. Angiogenesis was enhanced at both 1 and 10 weeks after treatment with VEGF121 as compared to controls (p < .001). No statistical improvement in graft survival was evident after treatment with VEGF121. Ex vivo gene transfer to cartilage may be a promising gene therapy strategy to enhance revascularization--and, potentially, cartilage survival--under the proper conditions.

Adenoviridae↗
PubMed2002

Fetal therapy: state of the art.

OBJECTIVE: To review our experience with the use of sonography in evaluating potential candidates for in utero fetal therapy performed at The Center for Fetal Diagnosis and Treatment at The Children's Hospital of Philadelphia. METHODS: This review article was designed to discuss open hysterotomy for the 4 fetal surgical procedures that have been performed at our institution. The procedures included surgical repair of myelomeningocele, resection of sacrococcygeal teratoma in fetuses with nonimmune hydrops, resection of an enlarging congenital cystic adenomatoid malformation that is not amenable to thoracoamniotic shunting, and tracheal clip occlusion for severe left congenital diaphragmatic hernia. RESULTS: For each surgical procedure, the use of sonography in the prenatal diagnosis of the congenital anomaly was detailed, as were indications for surgery and surgical procedures, postoperative monitoring and finally delivery, postnatal treatment, and long-term follow-up. Three of the procedures have been reasonably successful with rather dramatic results in some cases such that these techniques are still being performed. The 1 exception was open hysterotomy for the tracheal clip procedure for congenital diaphragmatic hernia, which has been abandoned. CONCLUSIONS: Fetal therapy is a rapidly evolving specialty, which is being practiced at several centers in this country. Sonography is an integral part of this specialty practice and has been used extensively in the diagnosis of some congenital anomalies that have debilitating or lethal consequences for the fetus. Technologic improvements in both sonography and magnetic resonance imaging have assisted tremendously in the many advances herein reported in the diagnosis and treatment of the above-described 4 congenital anomalies.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMedDate not supplied

Adenoviral mediated gene transfer of PDGF-B enhances wound healing in type I and type II diabetic wounds.

We have shown that the genetically diabetic mouse (C57BLKS/J-m+/+Lepr(db)) has a wound healing and neovascularization deficit associated with an inability to recruit endothelial precursor cells (EPCs) to the wound. This may account for a fundamental mechanism in impaired diabetic wound healing. We hypothesized that the adenoviral mediated overexpression of platelet-derived growth factor-B (PDGF-B) would enhance wound healing, improve neovascularization, and recruit EPCs to the epithelial wound in three diabetic mouse models. Eight-mm full-thickness flank wounds were made in db/db, nonobese NOD/Ltj, streptozotocin, and C57BLKS/J mice. Wounds were treated with either 1 x 10(8) PFU Ad-PDGF-B or Ad LacZ or phosphate buffered saline solution. Wounds harvested at seven days were analyzed for epithelial gap, blood vessel density, granulation tissue area, and EPCs per high powered field. All three diabetic models have a significant wound healing and neovascularization defect compared to C57BLKS/J controls. Adenoviral-PDGF-B treatment significantly enhanced epithelial gap closure in db/db, streptozotocin, and nonobese NOD/Ltj mice as compared to diabetic phosphate buffered saline solution or Ad LacZ controls. A similar increase in the formation of granulation tissue and vessel density was also observed. All three models had reduced levels of GATA-2 positive EPCs in the wound bed that was corrected by the adenoviral mediated gene transfer of PDGF. EPC recruitment was positively correlated with neovascularization and wound healing. Three different diabetic models have a wound healing impairment and a decreased ability to recruit EPCs. The vulnerary effect of adenoviral mediated gene therapy with PDGF-B significantly enhanced wound healing and neovascularization in diabetic wounds. The PDGF-B mediated augmentation of EPC recruitment to the wound bed may be a fundamental mechanism of these results.

Adenoviridae↗