Biomedical subjects
Publications and source records attributed to M L Silen.
Thoracic duct injuries accompanying blunt thoracic trauma are rare. A significant number of these lesions, however, are associated with fracture-dislocation of the spine. In this report, we discuss the surgical management of chylothorax in this setting.
To improve the survival of newborns with congenital diaphragmatic hernia (CHD), preoperative stabilization with conventional ventilatory therapy and extracorporeal membrane oxygenation (ECMO) have been used. Measurements that quantify pulmonary function may allow an accurate assessment of lethal pulmonary hypoplasia and predict outcome. Pulmonary function tests (PFTs) were obtained in 20 infants preoperatively and postoperatively; these included measurements of compliance, dynamic compliance, and tidal volume. Overall survival was 75%. Six surviving infants were initially managed with ventilator therapy alone, followed by repair (group 1). The remaining 14 patients, who were moribund at presentation or whose initial ventilator therapy failed, were placed on ECMO and received repair during bypass; nine survived (group 2), and five died (group 3). Compliance, dynamic compliance, and tidal volume obtained at initial presentation and immediately preoperatively were significantly higher for group 1 as compared with groups 2 and 3. Infants whose initial compliance was greater than 0.25 mL/cm H2O/kg and initial tidal volume was greater than 3.5 mL/kg did not require ECMO. Ultimate improvement in compliance was noted in 5 of 6 patients in group 1, 8 of 8 patients in group 2, and 5 of 5 in group 3. This improvement followed an initial decline in compliance in 9 of 14 survivors, from 15% to 76%. All six patients in group 1 had tidal volumes of more than 4 mL/kg, as did 7 of 9 patients in group 2. Only one patient among the ECMO nonsurvivors (group 3) had a postoperative tidal volume of this magnitude. These data suggest that initial PFTs may predict which infants will require ECMO.(ABSTRACT TRUNCATED AT 250 WORDS)
Evaluation of mediastinal masses often involves an array of imaging procedures and percutaneous biopsy techniques. Despite this, surgical intervention with an open biopsy is often required, especially to diagnose mediastinal malignancies. We report 22 patients with mediastinal masses who were managed with thoracoscopic biopsy, as opposed to open biopsy. All of these patients either had unsuccessful fine-needle aspiration or were unacceptable candidates for percutaneous aspiration. The patients ranged in age from 11 months to 67 years with a mean age of 17.2 +/- 3.6 years. Thoracoscopy provided an accurate tissue diagnosis in 19 of the 22 patients (86%) without need for an open diagnostic procedure. In 1 patient, histoplasmosis was suspected from the thoracoscopic biopsy, but open thoracotomy was needed for confirmation. Of the 19 patients with a positive tissue diagnosis, 3 patients had bronchogenic cysts that were completely resected by thoracoscopy. The mean duration of chest tube drainage was 2.3 +/- 0.2 days, and there were no complications or procedure-related deaths. The average length of hospitalization was 6.0 +/- 0.8 days. We believe that thoracoscopy is a safe, rapid, and effective modality for the diagnosis of mediastinal masses. Accurate tissue diagnoses are obtained in most patients without the need for additional procedures. In addition, we have demonstrated that complete excision of certain benign lesions during thoracoscopy is possible.
Appendicitis remains a common and morbid illness in children. The history, epidemiology, pathophysiology, clinical presentation, diagnostic evaluation, and management of acute appendicitis are discussed in this article.
The regulation of human chorionic gonadotropin (hCG) secretion by placental trophoblasts is incompletely understood. A recent study reports that Interleukin-1 beta (IL-1 beta) stimulates hCG production in vitro by human, first trimester, placental trophoblasts, but not by a human choriocarcinoma cell line. Human decidua has been shown to produce IL-1 alpha and beta, and Tumor Necrosis Factor alpha (TNF alpha). The precise role(s) of these proteins in pregnancy is unknown. In the present study, hCG production by human choriocarcinoma cells (JAR) was evaluated in the presence of recombinant human IL-1 alpha (rHIL-1 alpha) and rHTNF alpha. hCG production was increased by rHIL-1 alpha in a dose-dependent manner, and heat-inactivation of this cytokine abolished the effect. Equimolar quantities of rHTNF alpha failed to influence hCG production or cell viability. IL-1 may be important in the regulation of hCG production by human trophoblasts, and therefore may play a physiologic role in pregnancy. Furthermore, TNF does not appear to participate in the regulation of the production of this hormone by human choriocarcinoma cells. This is the first demonstration of a divergence of activity of these two cytokines in the reproductive process.
The capacity of fetal and newborn hepatic macrophages to produce cachectin/tumor necrosis factor (TNF) has not been previously examined. The role that TNF plays in newborn infection is also unknown. In the present report, fetal and newborn rat hepatic macrophages have been maintained in short-term tissue culture, and are shown to produce TNF in response to in-vitro endotoxin stimulation. Cells obtained are morphologically and antigenically consistent with macrophages, and are depleted of accessory cells and lymphocytes. In response to increasing doses of endotoxin, fetal and newborn hepatic macrophages produce TNF, and this production is suppressed fully by pretreatment with dexamethasone. The results demonstrate that fetal and newborn hepatic macrophages possess the capability to produce TNF in vitro. We propose that TNF may play a role in the response of the fetus and newborn to bacterial infection.
Chronic inflammatory diseases are often associated with decreased red blood cell (RBC) mass. The cytokines cachectin/tumor necrosis factor-alpha (TNF) and interleukin 1 (IL 1) are produced by monocytes/macrophages in response to many inflammatory stimuli and have been implicated in the anemia of chronic disease. This study was undertaken to evaluate the mechanisms by which cachectin/TNF, IL 1, or endotoxin induce anemia. Hematologic parameters and RBC kinetics were quantitated in rats given chronic sublethal quantities of either recombinant human cachectin/TNF, recombinant human IL 1 alpha, or Salmonella endotoxin for 7 days. Cachectin/TNF or endotoxin treatment resulted in a 25 or 31% decrease, respectively, in total RBC mass, whereas RBC mass was unchanged by IL 1 administration. Anemia associated with either chronic cachectin or endotoxin administration was characterized by normal mean corpuscular volume, mean corpuscular hemoglobin content, and reticulocyte numbers. [59Fe]RBC survival was significantly shortened in animals given cachectin, IL 1 or endotoxin, but the magnitude of the response was greatest in cachectin/TNF-or endotoxin-treated rats. Although cachectin/TNF-IL 1-, or endotoxin treatment resulted in similar hypoferremia and shortened plasma iron half-life, endotoxin or cachectin/TNF treatment (but not IL 1) significantly reduced the incorporation of plasma 59Fe into newly synthesized RBCs. We conclude that chronic cachectin/TNF administration produces anemia by decreasing RBC synthesis and reducing the life span of circulating RBCs. An endogenous cachectin/TNF response during inflammatory disease may contribute to an associated anemic state, whereas the modestly reduced red cell life span induced by IL 1 does not lead to a net reduction in RBC mass, presumably owing to a preserved RBC synthetic rate.
Bacterial endotoxins (LPS) causes placental injury and fetal demise in pregnant animals. Because several biological effects of LPS are mediated by interleukin-1 (IL-1) and tumor necrosis factor (TNF), the hypothesis that these cytokines could cause placental injury similar to that seen in LPS-treated pregnant rats was tested. On day 12 of gestation, rats were injected intraperitoneally with saline, LPS, native or heat-inactivated (HI) rHIL 1 alpha, or rH-TNF alpha. Seven days later, grossly abnormal implantation sites and fetal demise were observed in rats injected with rHIL-1, rHTNF, or LPS but not in those injected with saline or HI-cytokines. Necrosis of placental, decidual, and fetal tissues was observed in cytokine-treated animals. The necrosis was more severe in LPS-treated rats, in which no fetal remains were identifiable. These data suggest that IL-1 and TNF may play a role in the fetoplacental injury observed in LPS-treated pregnant rats.
Penile agenesis is a rare condition requiring gender reassignment and staged perineal reconstruction. This report describes two children reconstructed by taking advantage of the posterior sagittal approach. This approach allows a precise anatomic dissection, construction of a neovagina and accurate positioning of all perineal orifices. We think that this is the preferred approach for this rare condition.
BACKGROUND: The early experience with thoracoscopy in children has involved the diagnosis and treatment of pleural and pulmonary diseases. Recent advances have allowed surgeons to perform more complex procedures through video-assisted thoracoscopic surgery (VATS), potentially decreasing the pain and pulmonary impairment associated with an open thoracotomy. The authors report their initial experience with thoracoscopic assisted anterior spinal exposure and release as part of the treatment for children with spinal deformities. METHODS: A retrospective chart review of five children who underwent VATS for anterior spinal surgery between June 1995 and January 1997 was performed. RESULTS: The ages of the patients ranged from 11 to 16 years with a mean of 13.4 years. All patients had an anterior spinal release with or without fusion and same-day posterior spinal fusion with instrumentation. VATS was successfully completed in all patients without major morbidity and no mortality. The average operative time for the anterior portion of the procedure was 305 minutes, and a mean of 7 disc levels were released. Mean length of chest tube drainage and hospitalization were 6.8 and 8.6 days, respectively. CONCLUSIONS: The objectives of anterior exposure for spinal surgery in children can safely and effectively be accomplished using minimally invasive surgery.