PubMed Health⌕ Search

Biomedical subjects

Peter W Dillon

Publications and source records attributed to Peter W Dillon.

7 recordsLinked to original sources
PubMed2005

Persistent vascular defects in lung allografts attributed to defective endogenous endothelial progenitors.

BACKGROUND: A major pathological finding in human newborns with pulmonary hypoplasia and congenital diaphragmatic hernia is the presence of vascular abnormalities in lungs. Vasculogenesis/angiogenesis are crucial to lung development. To study lung alveolar development, including microvascular formation in fetal lung implants, Schwarz et al. [1] developed a subcutaneous allograft model. We adopted their model to assess the influence of neovascularization or the "host-graft vascular development" on hypoplastic lung structure and growth. MATERIALS AND METHODS: Normal and hypoplastic lungs at pseudoglandular stage were implanted subcutaneously under the dorsolateral fold of immunocompromised nude mice (athymic, nu/nu). Lung allografts were removed and assessed at 2, 4, 6, and 8 weeks postimplantation. RESULTS: Neovascularization of implanted lungs from subcutaneous vasculature of nude mice resulted in varying degrees of maturation of implanted normal and hypoplastic lungs. By 4 weeks, implanted normal lungs contained Type 2-like cells and by 7 to 8 weeks, Type 2 and Type 1-like cells, air spaces had enlarged, and surfactant secretion was observed. Despite some differentiation and maturation of hypoplastic lungs, there was more mesenchymal tissue, no secondary septa, and smaller air spaces compared to normal lungs. CONCLUSIONS: (a) Neovascularization or host-graft vascular development occurs in both normal and hypoplastic lung allografts. (b) Development and maturation of implanted normal and hypoplastic lungs follow the establishment of the vascular connections between the host and grafts. (c) The host-graft vascular connections do not improve the growth of normal or hypoplastic lungs. (d) Neovascularization failed to overcome the embryonic defects in vascular formation and the pulmonary vasculogenesis remained defective in hypoplastic lung allografts, which may be attributed to the defective endogenous endothelial progenitor cells.

Animals↗
PubMed2004

Prophylactic urokinase in the management of long-term venous access devices in children: a Children's Oncology Group study.

PURPOSE: Infection and thrombosis are serious complications of long-term vascular access devices in children undergoing chemotherapy. Since routine fibrinolytic therapy may decrease these complications, the purpose of this study was to compare the efficacy of an every-2-week administration of urokinase with standard heparin flushes in reducing the incidence of device-related infections and occlusions. MATERIALS AND METHODS: This study was a prospective, randomized phase III multicenter trial conducted by the Children's Cancer Group, in which patients with implantable ports or tunneled catheters received either urokinase or heparin every 2 weeks for 12 months. Study end points were time to first occlusion or time to first device-related infection. RESULTS: Five hundred seventy-seven patients from 29 institutions were enrolled, of whom 51% had external catheters and 49% had ports. Urokinase administration resulted in fewer occlusive events than heparin (23% v 31%; P =.02), a longer time to first occlusive event (log-rank analysis, P =.006), and a 1.6-fold difference in the rate of occlusive events (Poisson regression, P =.003). Similar results were noted when comparing ports and tunneled catheters. The urokinase group also had a 1.4-fold difference in the rate of infection (Poisson regression, P =.05) and longer time to first infection (log-rank, P =.07), but the difference was significant only in tunneled catheters. CONCLUSION: Urokinase administration every 2 weeks significantly affects the rate of occlusive events in ports and tunneled catheters and of infectious events in external catheters compared with heparin administration.

Adolescent↗
PubMed2004

The relationship of pulmonary artery pressure and survival in congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Pulmonary hypertension is an integral part of the pathophysiology of the respiratory failure associated with congenital diaphragmatic hernia. Hypothesizing that the evolution of the pulmonary hypertension would determine clinical outcome, the authors examined pulmonary artery pressures in relation to survival in their CDH patients. METHODS: The authors performed a retrospective chart review of all neonates with the CDH from 1991 to 2002 at their institution eliminating infants with complex congenital heart disease, prematurity, or limited treatment. Cardiac ECHO data were used to estimate pulmonary artery pressures as a ratio to systemic pressure. Statistical analyses of estimated pulmonary pressure ratios stratified by survival status and time were performed using chi2 and Fisher's Exact Test methods. RESULTS: Forty-seven full-term CDH infants with 428 cardiac ECHO evaluations were studied. Long-term survival rate was 74%. Forty-nine percent of patients had normal pulmonary artery pressure estimates within the first 3 weeks of life. All patients survived. Seventeen percent had persistent systemic or suprasystemic pressure estimates unrelieved by treatment interventions resulting in 100% mortality rate. Thirty-four percent had intermediate reductions in pressure estimates over time with 75% survival rate. Systemic pulmonary artery pressures were associated with decreased survival at all time-points when compared with normal-pressure survivors: week 1, 60% (P <.003); week 3, 38% (P <.007); week 6, 0% (P <.02). CONCLUSIONS: The evolution of pulmonary hypertension is a critical determinant of survival in CDH patients with current treatment strategies. Three groups can be modeled with markedly different clinical performance patterns. Using serial cardiac ECHO examinations, pulmonary artery pressure estimations can be used to predict clinical outcome.

Blood Pressure↗
PubMed2002

Economic implications of current surgical management of gastroesophageal reflux disease.

BACKGROUND/PURPOSE: Surgical management of gastroesophageal reflux disease in children has evolved with the development of laparoscopy. Because concerns persist regarding increased costs associated with this technique, the authors studied the economic parameters of antireflux surgery at their institution. METHODS: Seventy-eight patients undergoing either laparoscopic or open fundoplication were studied retrospectively between June 1998 and June 2000 comparing average operating room costs, total inpatient costs, and length of stay. Univariate comparisons were performed using Student's t test, and multivariate analysis was performed using multiple linear regression. RESULTS: Univariate analysis showed that patients receiving the laparoscopic procedure had significantly shorter inpatient stays (2.4 v. 3.96 days; P =.004) than those receiving open procedures. Average operating room costs were similar (laparoscopic, $2,611; open, $2,162; P =.237), but total costs for the laparoscopic procedure were lower ($4,484 v $5,129; P =.006). Multivariate analysis results suggested that in addition to procedure type, patients who required an intensive care unit admission incurred $6,595 in additional total costs (P <.0001) and 4.8 additional hospital days (P <.0001). After controlling for other variables, the laparoscopic procedure did not significantly reduce total hospital costs ($447; P =.192) but was associated with a significant decrease in length of stay of 1.3 days (P <.0001). CONCLUSION: These results suggest that laparoscopic procedures are comparable with open operations in terms of operative costs and that other factors are important determinants of the costs associated with antireflux surgery in children.

Child↗
PubMed2002

An introduction to economic evaluation for pediatric surgeons.

In the last decade, the field of medicine has undergone irreversible changes in the relationship between the financing and delivery of health care. Because health care resources no longer can be treated as limitless, all providers are being forced to set priorities on services and are being held more accountable for quality of care. These changes have had a particular impact on surgical specialities. Because the discipline of economics is the study of the optimal allocation of scarce resources, it is not surprising that many of the methods of economic analysis now are being applied to outcomes research in surgery. Economic evaluation serves as the core methodology for the establishment of best practice guidelines through the growing field of evidenced-based medicine. The primary tools of economic evaluation include cost analysis, cost of illness analysis, cost-benefit analysis, cost-effectiveness analysis, and cost-utility analysis. This report provides an introduction of these methods to enable pediatric surgeons to understand and critically evaluate these investigations as applied in pediatric surgery.

Benchmarking↗
PubMedDate not supplied

Splenic torsion.

Explore the source record for details and available documents.

Child, Preschool↗