Ontogeny of cholinergic regulation of fetal upper gastrointestinal motility

OBJECTIVE

In the fetal rabbit immediately prior to birth (day 30; 0.97 gestation), intragastric atropine suppresses upper gastrointestinal (GI) motility, indicating that cholinergic receptors are expressed and functional at birth. To explore the developmental timing of upper GI cholinergic receptor function, we assessed the effect of intragastric atropine administration in rabbit fetuses during the last 10% of gestation.

METHODS

Pregnant rabbits were studied at day 27, day 28 and day 29 of their normal 31-day gestation. In each litter, two fetuses were selected as study fetuses and two as control fetuses. Under ultrasound guidance, fluorescein and either atropine (0.04 microg/g fetal body weight) or normal saline were injected into the fetal stomach. Two hours after injection, fetuses were delivered and the small intestine was harvested. The per cent motility was calculated as the fluorescein travel distance, which was measured by ultraviolet light optical density, divided by the total small intestinal length.

RESULTS

Fetal body weight, small intestinal length and per cent motility increased from day 27 to day 29 (p < 0.01). There were no differences in fetal body weight and small intestinal length between atropine and control groups. Atropine significantly decreased per cent motility (versus control values) in fetuses at day 29 and day 28 (56.1 +/- 13.5 vs. 66.1 +/- 11.7% and 59.7 +/- 15.6 vs. 68.3 +/- 11.7%, respectively; p < 0.05), but not at day 27 (52.4 +/- 12.9 vs. 52.8 +/- 11.2%).

CONCLUSIONS

These results indicate that upper GI functional cholinergic receptors develop between 0.87 and 0.90 of rabbit gestation. Extrapolation to human development suggests that reduced GI motility in preterm human infants results, in part, from immature GI cholinergic receptors.

Reactive site-dependent phenotypic alterations in plasminogen activator inhibitor-1 transgenic mice

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of plasminogen activators (PAs) and plays a role in the regulation of a number of physiological processes including the degradation of extracellular matrix proteins, cell proliferation and migration, and intracellular signaling.

AIM

To characterize the effects of durable expression of a stable form of human PAI-1 and to characterize important structure-function relationships in PAI-1 in vivo.

METHODS

We developed transgenic mice lines overexpressing stable variants of human PAI-1 under the control of the murine preproendothelin-1 promoter and characterized the phenotypic alterations displayed by transgenic mice.

RESULTS

Transgenic mice expressing an active form of human PAI-1 (PAI-1-stab) display complex phenotypic abnormalities including alopecia and hepatosplenomegaly. Reactive site mutant transgenic mice expressing inactive PAI-1 exhibit complete phenotypic rescue, while transgenic mice expressing PAI-1 with reduced affinity for vitronectin manifest all of the phenotypic abnormalities present in PAI-1-stab transgenic mice.

CONCLUSIONS

The protease inhibitory activity of PAI-1 toward PAs and/or other serine proteases is necessary and sufficient to promote complex phenotypic abnormalities and mediates many of the physiological effects of PAI-1 in vivo.

Experience with the Arndt paediatric bronchial blocker

Previously reported techniques for single lung ventilation in children have failed to provide consistent, single lung ventilation with relative ease and reliability. We report our experience with the use of a new device, the Arndt 5 French (Fr) paediatric endobronchial blocker, for single lung ventilation in a series of 24 children. We were able to achieve single lung ventilation in 23 of the 24 patients (aged 2-16 yr). Placement required approximately 5-15 min. Attempts at placement were aborted in one patient who was unable to tolerate even short periods of apnoea because of lung pathology. Although it has some limitations, our experience suggests that the paediatric bronchial blocker can be used as a consistent, safe method of single lung ventilation in most young children.

Tissue- and agonist-specific regulation of human and murine plasminogen activator inhibitor-1 promoters in transgenic mice

Numerous studies have described regulatory factors and sequences that control transcriptional responses in vitro. However, there is a paucity of information on the qualitative and quantitative regulation of heterologous promoters using transgenic strategies. In order to investigate the physiological regulation of human plasminogen activator inhibitor type-1 (hPAI-1) expression in vivo compared to murine PAI-1 (mPAI-1) and to test the physiological relevance of regulatory mechanisms described in vitro, we generated transgenic mice expressing enhanced green fluorescent protein (EGFP) driven by the proximal -2.9 kb of the hPAI-1 promoter. Transgenic animals were treated with Ang II, TGF-beta1 and lipopolysaccharide (LPS) to compare the relative activation of the human and murine PAI-1 promoters. Ang II increased EGFP expression most effectively in brain, kidney and spleen, while mPAI-1 expression was quantitatively enhanced most prominently in heart and spleen. TGF-beta1 failed to induce activation of the hPAI-1 promoter but potently stimulated mPAI-1 in kidney and spleen. LPS administration triggered robust expression of mPAI-1 in liver, kidney, pancreas, spleen and lung, while EGFP was induced only modestly in heart and kidney. These results indicate that the transcriptional response of the endogenous mPAI-1 promoter varies widely in terms of location and magnitude of response to specific stimuli. Moreover, the physiological regulation of PAI-1 expression likely involves a complex interaction of transcription factors and DNA sequences that are not adequately replicated by in vitro functional studies focused on the proximal -2.9 kb promoter.

Robotic surgery and resident training

BACKGROUND

Robotic technology promises to have an important future in surgery, but few residency programs incorporate robotics into surgical training. We sought to compare the speed and accuracy with which junior residents could perform laparoscopic tasks using both a robotic surgical device (Zeus MicroWrist) and conventional laparoscopic instruments.

METHODS

Twelve residents performed exercises of progressive difficulty in an inanimate model using both the robot and conventional laparoscopy. Analysis of variance statistical analysis was used to compare task time and suturing accuracy scores.

RESULTS

Grasping and suturing exercises were performed significantly faster with conventional laparoscopic instruments than with the robot. However, no difference in task time was noted for intracorporeal knot tying. Accuracy scores for suturing were higher for the robot.

CONCLUSIONS

Junior residents can be instructed easily and quickly in both robotic and conventional advanced laparoscopic skills. The utility of robotic surgical devices in resident training requires further investigation.

Anticholinergic suppression of fetal rabbit upper gastrointestinal motility

OBJECTIVE

At birth the newborn digestive tract must assume the responsibility of assimilating nutrients for survival. Immature gastrointestinal motility in the neonate may result in impaired feeding and nutrition. Newborn gastrointestinal motility development requires the expression and functional maturation of gastrointestinal receptors. To explore the timing of fetal responses to gastrointestinal cholinergic motility agents, we assessed the effect of the anticholinergic agent atropine in the late-gestation rabbit fetus.

METHODS

Seven pregnant New Zealand White rabbits were studied at day 30 of their normal 31-day gestation. In each litter, two fetuses were selected as study (n = 14) and two as control (n = 14). Under ultrasound guidance, a spinal needle was percutaneously inserted through the maternal uterus into the fetal stomach and 0.5 ml of gastric content was aspirated. Fluorescein, labelled with colored microspheres, and either atropine (0.04 microg/g fetal body weight) or normal saline were injected in a total volume of 0.5 ml. Two hours after injection, fetuses were delivered, the small intestine harvested, and the total small intestinal length and the distance the gastrointestinal fluorescein travelled were measured by ultraviolet light optical density. The fluorescein travelled distance and the per cent motility, defined as the length of fluorescein travelled divided by the total length of the small intestine, were calculated.

RESULTS

All fetuses survived the intragastric injection. Mean fetal body weight at delivery was 44.2 +/- 6.7 and 46.8 +/- 7.2 g in atropine and control fetuses, respectively. The fluorescein travelled distance (15.4 +/- 4.2 vs. 19.0 +/- 4.3 cm;. p < 0.01) and per cent motility (51.0 +/- 8.9 vs. 63.8 +/- 11.7%; p < 0.01) of atropine-treated fetuses were significantly lower than those of control fetuses.

CONCLUSION

Fetal upper gastrointestinal motility is suppressed in response to intragastric atropine. These results indicate that fetal gastrointestinal cholinergic receptors are expressed and functional in the term (0.97 gestation) rabbit fetus. In utero administration of cholinergic agonists/antagonists may potentially modulate fetal gastrointestinal motility and absorption of amniotic fluid water and solutes.

Impact of mentor guidance in surgical career selection

PURPOSE

The aim of this study was to survey graduates of a university general surgical residency training program to determine factors that influenced their selection of a specialty field.

METHODS

A 39-item questionnaire was mailed to 86 graduates of a university general surgery program who matriculated from 1975 to 1989. The impact of lifestyle, technology, clinical opportunity, and mentor guidance in the residents' selection of a specialty field and eventual clinical practice was assessed. Results were analyzed using Fisher's Exact test with significance determined at P less than.05.

RESULTS

The response rate was 65% (56 of 86). Eighty percent of respondents identified the most important aspect influencing their choice of specialty was interest in that field; additional factors included perception of prestige, presence of clinical opportunity, mentor influence, and family priorities. Sixty-six percent of respondents chose the same career as their mentor, attributing this to the mentor's skill (n = 36, 68%), achievements (n = 35, 66%), and verbal recommendations about their specialty field (n = 24, 45%), p < 0.05.

CONCLUSIONS

Surgical residents use many criteria in selecting a field of specialty with mentor guidance an important component. Knowledge of these influential areas should help training programs offer appropriate career guidance. J Pediatr Surg 36:1802-1804.

Down-regulation of decorin, a transforming growth factor-beta modulator, is associated with scarless fetal wound healing

PURPOSE

Transforming growth factor beta (TGF-beta) bioactivity has been implicated as a potential regulator of the transition from scarless healing to scar formation in fetal wounds. Decorin is an extracellular matrix proteoglycan that regulates TGF-beta bioactivity and assists in collagen fibrillogenesis. To determine its role in scarless repair, the authors examined decorin expression in fetal fibroblasts, skin, and wounds.

METHODS

A single, full-thickness, 2-mm open wound was created on the dorsal surface of fetal rats at 16.5 days (E16) and 18.5 days (E18) gestational age (term, 21.5 days [E21]). Wounds were harvested at 24 and 72 hours (n = 12 wounds per time-point). Nonwounded fetal skin at E17, E19, and E21 was harvested for analysis of decorin expression during skin development and as controls for wounds. In addition, fetal (E14, E18) and adult dermal fibroblasts were cultured for in vitro analysis. Reduced-cycle, specific primer, reverse transcriptase polymerase chain reaction was performed to quantitate decorin expression.

RESULTS

Decorin expression increased rapidly with increasing gestational age in both fetal fibroblasts and skin. Expression was increased 22-fold in E18 fibroblasts (P <.002) and 300-fold in adult fibroblasts (P <.001) compared with E14 fibroblasts. In skin, expression increased 74% (P <.01) during the fetal wound healing transition period between E17 and E19. However, in E16 wounds (scarless), decorin expression decreased 59% (P <.006) at 24 hours and 45% (P <.02) at 72 hours. Decorin expression did not change in E18 (scar) wounds at 24 and 72 hours (P >.05).

CONCLUSIONS

Early gestation fetal fibroblasts and fetal skin express decorin at lower levels than late gestation fetal and adult fibroblasts and skin. Decorin expression is down-regulated in scarless (E16) compared with scar (E18) wounds. Thus, increased decorin expression is associated with both skin development and scar formation. Conversely, decreased decorin expression is associated with scarless repair.

Methodology standards associated with quality reporting in clinical studies in pediatric surgery journals

BACKGROUND/PURPOSE

Reports of clinical trials often lack adequate descriptions of design and analysis; recent attention has focused on improving this omission so readers can properly assess the strength of the findings and draw their own conclusions. Similar analysis of study design and methodologic standards associated with quality reporting has not been carried out for pediatric surgery journals.

METHODS

All studies (n = 642) published in 1998 in Journal of Pediatric Surgery (JPS) and Pediatric Surgery International (PSI), were reviewed for demographic data and study design. The frequency of reporting of 11 basic elements of design and analysis was evaluated in randomized clinical trials (RCT), nonrandomized clinical trials (NRCT), and retrospective cohorts (RC) from JPS by consensus of 2 assessors.

RESULTS

Of the 642 studies, 17% of articles (111 of 642) were classified as clinical studies. Sixty-three were comparative studies and consisted of RC (n = 48), NRCT (n = 12), and RCT (n = 3). Two-thirds of articles published were either case reports or case series (431 of 642), and 16% were basic science articles. Demographic analysis showed a wide range of topics addressed, 4 authors per article, and multiple country of origin of authors. More than 66% of all RCT in JPS reported on eligibility criteria, admission before allocation, random allocation, method of randomization, patients' blindness to treatment, treatment complications, statistical analyses, statistical methods, loss to follow-up, and statistical methods; 2 elements of design and analysis, however, were poorly reported: blind assessment of outcome (33%) and power (17%).

CONCLUSIONS

There were few randomized, controlled trials in pediatric surgery journals, and further attention should be given to evaluate the causal factors. Nine elements of quality reporting were well reported; however, 2 others were poorly reported; this may improve if editors of pediatric surgical journals provide authors with guidelines on how to report clinical trial design and analysis.

Gene transfer to the embryo: strategies for the delivery and expression of proteins at 48 to 56 hours postfertilization

BACKGROUND/PURPOSE

Although gene and protein transfer may potentiate the cure of genetic disease, current strategies involving fetal gene therapy remain nonfocal and confounded by the lack of imaging techniques and in vivo markers for precise gene transfer.

METHODS

Fourteen white Leghorn chick eggs were incubated for 48 to 56 hours postfertilization until they reached stages 11 to 16, about 3 mm in size. In 7 chick embryos, a glass needle was placed at the midbrain/hindbrain level and 1 x 10(7) pfu of an adenovirus containing the green fluorescent protein (GFP) reporter gene was injected into the lateral head. In another 7 chicken embryos, colored agarose beads coated with Sonic hedgehog (Shh) protein were implanted at the level of the hindbrain under direct microscopy. The eggs were then sealed, incubated at 37 degrees C for 24 hours, and reimaged using fluorescent microscopy and confocal laser microscopy.

RESULTS

At 24 hours postinjection, all embryos were alive and were imaged in vivo. Fluorescent microscopic imaging showed green fluorescence in the region of the injection site in all the embryos. In embryos that underwent bead placement, the beads were visualized under microscopy in the lateral hindbrain of all embryos, and the presence of the Shh protein was confirmed using fluorescein isothiocyanate (FITC)-conjugated secondary antibody.

CONCLUSIONS

This study shows that embryonic 3-mm chick embryos survive adenoviral transduction or agarose bead implantation in a focal manner in vivo and that this delivery results in production of imageable levels of protein. This may be used in mammalian systems, including humans, to introduce genes and proteins.

Determination of Interatomic Potentials for the X0(+), A0(+), and B1 States of HgKr from Fluorescence and Excitation Spectra

We present an analysis of the A0(+)(6(3)P(1))-->X0(+)(6(1)S(0)) bound-bound and bound-free fluorescence spectrum, and of the A0(+)(6(3)P(1))<--X0(+)(6(1)S(0)) and B1(6(3)P(1))<--X0(+)(6(1)S(0)) bound-bound excitation spectrum of the HgKr van der Waals molecule. The A-->X fluorescence spectrum, which was observed for the first time, as well as the excitation spectra were recorded using a pulsed supersonic molecular beam crossed with a pulsed dye laser beam. An analysis of the A(v')<--X(v"), B(v')<--X(v"), and A(v'=8)-->X(v") bound-bound bands indicates that a Morse function combined with a long-range approximation represents the interatomic potential energy curve of the A, B, and X states below the dissociation limit. In the simulation of the A(v'=8)-->X bound-free spectrum the Morse, Lennard-Jones (n-6), and Maitland-Smith (n(0), n(1)) functions were tested, and the Maitland-Smith (11.39, 10.50) potential was found to be a good representation of the repulsive part of the X-state PE curve above the dissociation limit, over the internuclear separation range R=2.85-3.55 Å. The spectroscopic characteristics for the A, B, and X states obtained in this work are compared with other available experimental and theoretical results. Copyright 2001 Academic Press.

The effects of tubulin-binding agents on stretch-induced ventricular arrhythmias

Stretch-activated ion channels have been identified as transducers of mechanoelectric coupling in the heart, where they may play a role in arrhythmogenesis. The role of the cytoskeleton in ion channel control has been a topic of recent study and the transmission of mechanical stresses to stretch-activated channels by cytoskeletal attachment has been hypothesized. We studied the arrhythmogenic effects of stretch in 16 Langendorff-perfused rabbit hearts in which we pharmacologically manipulated the microtubular network of the cardiac myocytes. Group 1 (n=5) was treated with colchicine, which depolymerizes microtubules, and Group 2 (n=6) was treated with taxol, which polymerizes microtubules. Stretch-induced arrhythmias were produced by transiently increasing the volume of a fluid-filled left ventricular balloon with a volume pump driven by a computer-controlled stepper motor. Electrical events were recorded by a contact electrode which provided high-fidelity recordings of monophasic action potentials and stretch-induced depolarizations. The probability of eliciting a stretch-induced arrhythmia increased (0.22+/-0.11 to 0.62+/-0.19, p=0.001) in hearts treated with taxol (5 microM), whereas hearts treated with colchicine (100 microM) showed no statistically significant change. We conclude that proliferation of microtubules increased the arrhythmogenic effect of transient left ventricle diastolic stretch. This result indicates a possible mode of arrhythmogenesis in chemotherapeutic patients and patients exhibiting uncompensated ventricular hypertrophy. The data would indicate that the cytoskeleton represents a possible target for antiarrhythmic therapies.

Indications for pediatric intestinal transplantation: a position paper of the American Society of Transplantation

Parenteral nutrition represents standard therapy for children with short bowel syndrome and other causes of intestinal failure. Most infants with short bowel syndrome eventually wean from parenteral nutrition, and most of those who do not wean tolerate parenteral nutrition for protracted periods. However, a subset of children with intestinal failure remaining dependent on parenteral nutrition will develop life-threatening complications arising from therapy. Intestinal transplantation (Tx) can now be recommended for this select group. Life-threatening complications warranting consideration of intestinal Tx include parenteral nutrition-associated liver disease, recurrent sepsis, and threatened loss of central venous access. Because a critical shortage of donor organs exists, waiting times for intestinal Tx are prolonged. Therefore, it is essential that children with life-threatening complications of intestinal failure and parenteral nutrition therapy be identified comparatively early, i.e. in time to receive suitable donor organs before they become critically ill. Children with liver dysfunction should be considered for isolated intestinal Tx before irreversible, advanced bridging fibrosis or cirrhosis supervenes, for which a combined liver and intestinal transplant is necessary. Irreversible liver disease is suggested by hyperbilirubinemia persisting beyond 3-4 months of age combined with features of portal hypertension such as splenomegaly, thrombocytopenia, or prominent superficial abdominal veins; esophageal varices, ascites, and impaired synthetic function are not always present. Death resulting from complications of liver failure is especially common during the wait for a combined liver and intestinal transplant, and survival following combined liver and intestinal Tx is probably lower than following an isolated intestinal transplant. The incidence of morbidity and mortality following intestinal Tx is greater than that following liver or kidney Tx, but long-term survival following intestinal Tx is now at least 50-60%. It is probable that outcomes shall improve in the future with continued refinements in operative technique and post-operative management, including immunosuppression.

Centrilobular endothelial cell injury by diquat in the selenium-deficient rat liver

Low doses of diquat cause massive liver necrosis and death of selenium-deficient rats within a few hours. Protection against this injury by selenium correlates with the presence of selenoprotein P, an extracellular selenoprotein that associates with endothelial cells. Selenium-deficient rats were injected with diquat (10 mg/kg) and their livers were removed for light and electron microscopy at times up to 120 minutes after injection. Selenium-replete animals were studied before and 120 minutes after the same dose of diquat. With selenium deficiency, diquat caused injury to centrilobular endothelial cells. This injury was evident 20 minutes after diquat injection and progressed to cell loss at 60 minutes after diquat injection. At 120 minutes, endothelial cells were virtually absent from the centrilobular regions and hepatocytes in those areas were undergoing necrosis. Portal and midzonal areas remained normal in selenium-deficient livers, as did the entire liver lobule of selenium-replete rats. These findings indicate that the initial liver lesion in selenium-deficient rats given diquat is injury of the endothelial cells in the centrilobular region. After detachment of the endothelial cells, centrilobular hepatocytes undergo necrosis. We postulate that selenoprotein P protects the centrilobular endothelial cells against injury by oxidant molecules that result from diquat administration.

Surgical aspects of dialysis in newborns and infants weighing less than ten kilograms

PURPOSE

Renal failure occurs in children with moderate frequency. Surgical aspects of establishing and maintaining dialysis access in small infants are exceptionally challenging. The purpose of this review is to evaluate the authors' experience with dialysis access for infants less than 10 kg, particularly with respect to the surgical care required.

METHODS

A retrospective review was conducted between 1991 and 1999 of all pediatric dialysis patients weighing 10 kg or less (n = 29). Age at start of dialysis, duration of dialysis, modes of dialysis, and complications specific to peritoneal (PD) and hemodialysis (HD) were examined.

RESULTS

The mean age at start of dialysis was 10.4 months and continued for an average duration of 16.3 months. Seventy-two percent of all patients required both modes of dialysis. HD and PD duration averaged 7.8 and 10.5 months, respectively. Catheter durability was 3.1 and 4.5 months per catheter for HD and PD, respectively. There was no significant difference in complications when comparing HD and PD. Patients who weighed 5 to 10 kg had significantly longer PD catheter durability than patients 0 to 5 kg (P = .001). Forty-one percent of patients terminated dialysis after transplantation, whereas 24% died awaiting transplantation.

CONCLUSION

Despite a large number of operations required, infants less than 10 kg can be bridged successfully, by surgical intervention and subsequent dialysis, to transplantation.

Extracorporeal membrane oxygenation for cardiac support in pediatric patients

Extracorporeal membrane oxygenation (ECMO) has been used for pediatric cardiac support in settings of expected mortality due to severe myocardial dysfunction. We reviewed the records of 34 children (<18 years) placed on ECMO between March 1995 and May 1999. Demographic, cardiac, noncardiac, and outcome variables were recorded. Data were subjected to univariate analysis to define predictors of outcome. Eighteen patients were placed on ECMO after cardiac surgery (Group A); seven of 18 were weaned off ECMO, and four survived to discharge (22%). Thirteen patients were placed on ECMO as a bridge to cardiac transplantation (Group B), six of 13 received a heart transplant, one recovered spontaneously, and six survived to discharge (46%). Three patients were placed on ECMO for failed cardiac transplantation while awaiting a second transplant (Group C); one recovered graft function, two received a second heart transplant, and two of three survived (66%). The primary cause of death was multiorgan system failure (68%). Group A patients supported on ECMO for more than 6 days did not survive. Mediastinal bleeding complications and renal failure requiring dialysis were associated with nonsurvival. We conclude that ECMO as a bridge to cardiac transplant was more successful than ECMO support after cardiotomy. Mediastinal bleeding and renal failure were associated with poor outcome. Recovery of cardiac function occurred within the first week of ECMO support if at all. Longer support did not result in survival without transplantation.

Pyloroplasty improves long-term gastric emptying in rats undergoing fundoplication

BACKGROUND

Conflicting reports exist regarding the permanence of improved gastric emptying (GE) after fundoplication for gastroesophageal reflux in children.

METHODS

Changes in gastric volume (GV) and GE of a radiolabeled mixed meal induced by a Nissen fundoplication (NF) were compared with those with a NF plus pyloroplasty (NF + P). GE was measured preoperatively, 15 and 30 days postoperation, in 24 Sprague-Dawley rats; 12 had NF alone, and 12 had NF + P Results were expressed as percent gastric retention at 90 minutes (GR90). GV was measured at the same time periods in 20 additional rats.

RESULTS

NF rats had enhanced GE with reduction of preoperative GR90 from 37.6% to 23.7% at 15 days (P < .05); however, at 30 days the GR90 increased to 34.3%. NF + P rats had enhanced GE with reduction in GR90 from 37.2% to 20.8% at 15 days (P< .05), which persisted at 30 days (20.4%). Mean GV decreased from (1.36 mL/100 g body weight) preoperation to 0.86 at 15 days (P< .05) at 15 days in the NF group, and returned to 1.29 at 30 days. Mean GV decreased from 1.36 to 0.91 at 15 days in the NF + P rats and persisted at 0.90 at 30 days.

CONCLUSION

In the rat model, NF enhances GE transiently, whereas NF + P produces long-term enhancement of GE.

Hepatic cryoablation, but not radiofrequency ablation, results in lung inflammation

OBJECTIVE

To compare the effects of 35% hepatic cryoablation with a similar degree of radiofrequency ablation (RFA) on lung inflammation, nuclear factor kappaB (NF-kappaB) activation, and production of NF-kappaB dependent cytokines.

SUMMARY BACKGROUND DATA

Multisystem injury, including acute lung injury, is a severe complication associated with hepatic cryoablation of 30% to 35% or more of liver parenchyma, but this complication has not been reported with RFA.

METHODS

Sprague-Dawley rats underwent 35% hepatic cryoablation or RFA and were killed at 1, 2, and 6 hours. Liver and lung tissue were freeze-clamped for measurement of NF-kappaB activation, which was detected by electrophoretic mobility shift assay. Serum concentrations of tumor necrosis factor alpha and macrophage inflammatory protein 2 were measured by enzyme-linked immunosorbent assay. Histologic studies of pulmonary tissue and electron microscopy of ablated liver tissue were compared among treatment groups.

RESULTS

Histologic lung sections after cryoablation showed multiple foci of perivenular inflammation, with activated lymphocytes, foamy macrophages, and neutrophils. In animals undergoing RFA, inflammatory foci were not present. NF-kappaB activation was detected at 1 hour in both liver and lung tissue samples of animals undergoing cryoablation but not after RFA, and serum cytokine levels were significantly elevated in cryoablation versus RFA animals. Electron microscopy of cryoablation-treated liver tissue demonstrated disruption of the hepatocyte plasma membrane with extension of intact hepatocyte organelles into the space of Disse; RFA-treated liver tissue demonstrated coagulative destruction of hepatocyte organelles within an intact plasma membrane. To determine the stimulus for systemic inflammation, rats treated with cryoablation had either immediate resection of the ablated segment or delayed resection after a 15-minute thawing interval. Immediate resection of the cryoablated liver tissue prevented NF-kappaB activation and lung injury; however, pulmonary inflammatory changes were present when as little as a 15-minute thaw interval preceded hepatic resection.

CONCLUSIONS

Hepatic cryoablation, but not RFA, induces NF-kappaB activation in the nonablated liver and lung and is associated with acute lung injury. Lung inflammation is associated with the thawing phase of cryoablation and may be related to soluble mediator(s) released from the cryoablated tissue. These findings correlate the clinical observation of an increased incidence of multisystem injury, including adult respiratory distress syndrome (ARDS), after cryoablation but not RFA.

Comparison of intratracheal pulmonary ventilation and hybrid intratracheal pulmonary ventilation with conventional mechanical ventilation in a rabbit model of acute respiratory distress syndrome by saline lavage

OBJECTIVES

To study changes in PaCO2 and PaO2 during intratracheal pulmonary ventilation (ITPV) and hybrid intratracheal pulmonary ventilation (h-ITPV) compared with conventional mechanical ventilation (CMV) in a rabbit model of respiratory failure, and to define the technique of h-ITPV that combines conventional mechanical ventilation and ITPV.

DESIGN

Prospective, interventional study.

SUBJECTS

Twelve adult New Zealand White rabbits.

INTERVENTIONS

Surfactant deficiency was induced by saline lavage, and rabbits were randomized to either ITPV or h-ITPV. The study consisted of four phases: phase 0, CMV after saline lavage, ventilator rate 30 breaths/min; phase I, ITPV or h-ITPV initiated at the same pressure and rate as in phase 0; phase II, ITPV or 1.0 L/min h-ITPV bias flow, with peak inspiratory pressure (PIP) decreased and ventilator rate increased to achieve the lowest tidal volume while maintaining adequate gas exchange; and phase III, animals returned to CMV.

MEASUREMENTS AND MAIN RESULTS

In phase I, no difference in PaCO2 was observed between ITPV, h-ITPV, or CMV. There was a decrease in PaO2 when switching from CMV to ITPV but not to h-ITPV. In phase II, it was possible to decrease PIP (average of 37% for ITPV and 36% for h-ITPV) and tidal volume (average of 64% for ITPV and 53% for h-ITPV) without compromising gas exchange (p < .05). Oxygenation tended to improve from phase 0 to the end of phase II. In phase III, PaCO2 increased (average of 71% for ITPV and 79% for h-ITPV) and pH decreased (p < .05). Normocapnia was achieved using significantly higher PIP and tidal volume, compared with phase 0 (p < .05).

CONCLUSIONS

ITPV and h-ITPV can effectively ventilate and oxygenate rabbits with surfactant-deficient lungs at tidal volumes and therefore pressures lower than required with CMV. Maximum benefit appears to occur at high ventilator rates. These findings suggest that both modes of ventilation may represent powerful new tools in the management of patients with acute respiratory failure. (Crit Care Med 2000; 28:774-781)

Repair of pectus excavatum deformities: 30 years of experience with 375 patients

OBJECTIVE

To review the surgical experience with pectus excavatum chest deformities at UCLA Medical Center during a 30-year period.

BACKGROUND

Pectus excavatum is a relatively common malformation that is often symptomatic; however, children's physicians often do not refer patients for surgical correction.

METHODS

Hospital records from 375 patients who underwent repair of pectus excavatum deformities between 1969 and 1999 were reviewed. Decrease in stamina and endurance during exercise was reported by 67%; 32% had frequent respiratory infections, 8% had chest pain, and 7% had asthma. The mean pectus severity score (width of chest divided by distance between posterior surface of sternum and anterior surface of spine) was 4.65 (normal chest = 2.56). All patients had marked cardiac deviation into the left chest. Repair was performed with subperiosteal resection of the abnormal cartilages, transverse wedge osteotomy of the anterior sternum, and internal support with a steel strut for 6 months. Repair was performed on 177 children before age 11 years; 38 adults with severe symptoms underwent repair.

RESULTS

The mean hospital stay was 3.1 days. With a mean follow-up of 12.6 years, all patients with preoperative respiratory symptoms, exercise limitation, and chest pain experienced improvement. Vital capacity increased 11% (mean) within 9 months in 35 patients evaluated. There were no deaths. Complications included hypertrophic scar formation (35), atelectasis (12), pleural effusion (13), recurrent sternal depression (5), and pericarditis (3). More than 97% had a very good or excellent result.

CONCLUSION

Pectus excavatum deformities can be repaired with a low rate of complications, a short hospital stay, and excellent long-term physiologic and cosmetic results.

Favorable biology and outcome of stage IV-S neuroblastoma with supportive care or minimal therapy: a Children's Cancer Group study

PURPOSE

Stage IV-S neuroblastoma is a metastatic disease associated with spontaneous regression and good survival, but 10% to 20% of infants die from early complications. The purpose of this study was to evaluate outcome and prognostic factors in infants with stage IV-S neuroblastoma treated prospectively with supportive care only or, in symptomatic patients, with low-dose cytotoxic therapy.

PATIENTS AND METHODS

Eighty eligible infants were studied for response and survival with supportive care or, for symptomatic patients, cyclophosphamide 5 mg/kg/d for 5 days with or without hepatic radiation of 4.5 Gy over 3 days. Staging was reviewed centrally, and MYCN gene copy number, Shimada histopathologic classification, serum ferritin levels, and bone marrow immunocytology were determined.

RESULTS

Stage IV-S and International Neuroblastoma Staging System stage 4S were 98% concordant. MYCN was not amplified in any of the tumors tested (n = 58), and Shimada histopathologic classification was favorable in 96% (n = 68/71). The 5-year event-free survival (EFS) rate for all infants was 86% and the survival rate was 92%. Supportive care was the only treatment provided for 44 (55%) of 80 infants, and their 5-year survival rate was 100%, compared with 81% survival for those requiring cytotoxic therapy for symptoms (P =.005). Five of six deaths were in infants younger than 2 months of age at diagnosis and were due to complications of extensive abdominal involvement with respiratory compromise or disseminated intravascular coagulation. Although age </= 3 months at diagnosis was significant for EFS (P =. 043), it was less significant for survival (P =.077). The only other significant factor predictive for improved survival was favorable Shimada histopathologic classification. Sites of metastatic involvement (liver, skin, or bone marrow) and surgical resection of the primary tumor were not significant for survival.

CONCLUSION

This study confirms the favorable biologic features and excellent survival of infants with stage IV-S neuroblastoma with minimal therapy. Infants younger than 2 months old at diagnosis with rapidly progressive abdominal disease may benefit from earlier and more intensive treatment.

Biologic variables in the outcome of stages I and II neuroblastoma treated with surgery as primary therapy: a children's cancer group study

PURPOSE

To determine prospectively whether surgery alone is sufficient therapy for Evans stages I and II neuroblastoma and to define biologic and clinical features having prognostic potential for this group.

PATIENTS AND METHODS

Between June 1989 and August 1995, 374 eligible children (age range, 0 to 18 years) with newly diagnosed stage I (n = 141) and stage II (n = 233) neuroblastoma were registered onto Children's Cancer Group trial 3881. Surgical resection was the only primary therapy except in cases with spinal cord compression, where radiation therapy was allowed. Event-free survival (EFS) and overall survival (OS) were analyzed by life-table methods according to clinical and biologic features.

RESULTS

EFS and OS (mean +/- SE) for all stage I patients were 93% +/- 3.0% and 99% +/- 1.0%, respectively, compared with 81% +/- 4.0% and 98% +/- 2. 0%, respectively, for stage II patients. The significantly higher recurrence rate among stage II patients was managed successfully in 38 of 43 children with either surgery or multimodality treatment. There was one death among stage I patients and six among stage II. For stage II patients tumor MYCN gene amplication, unfavorable histopathology, an age greater than 2 years, and positive lymph nodes predicted a lower OS (P <.05).

CONCLUSION

Children with stages I and II neuroblastoma have 98% survival with surgery alone as primary therapy. Supplemental treatment was necessary in only 10% of stage I patients and 20% of stage II patients. In children with localized neuroblastoma, a subset of patients that are at higher risk for death can be defined as those with stage II disease who have tumor MYCN amplification or who are >/= 2 years of age with either unfavorable histopathology or positive lymph nodes.

Prolongation of primate cardiac allograft survival by treatment with ANTI-CD40 ligand (CD154) antibody

BACKGROUND

We evaluated whether a humanized anti-CD154 antibody (hu5c8) prolongs primate cardiac allograft survival.

METHODS

Heterotopic cardiac allografts were performed between MHC class II-mismatched cynomolgus monkeys. Survival was compared between groups treated with a perioperative dosing of hu5c8 (group 1; n=6), sustained dosing with hu5c8 (group 2; n=3), and control regimens (n=4). All recipients received fresh donor-specific transfusions during surgery.

RESULTS

Median graft survival was 49 days (range 14 to 56) in group 1 and 106 days (range 56 to 245) in group 2, compared with 5 days (range 5 to 6) for controls (P<0.05 for all comparisons). Lymphocytic infiltrates were often present in hu5c8-treated grafts with stable contractility. Donor-specific mixed lymphocyte reaction was generally preserved. Vasculitis and cellular intimal proliferation were prevalent in rejected grafts but occurred later and were less prevalent in group 2.

CONCLUSIONS

Anti-CD154 antibody markedly prolongs the survival of cardiac allografts in primates and is well tolerated. Sustained dosing with hu5c8 yielded improved survival and may be associated with a lower incidence of vascular pathology. We conclude that hu5c8 therapy is an effective approach for inhibiting acute cardiac allograft rejection in primates.

Longitudinal analysis of fibroblast growth factor expression after transplantation and association with severity of cardiac allograft vasculopathy

BACKGROUND

Vascular smooth muscle cell growth factors are postulated to contribute to cardiac allograft vasculopathy (CAV). Few data quantitatively address the timing, location, or stimuli for growth factor expression and relationship to CAV.

METHODS AND RESULTS

Acidic fibroblast growth factor (aFGF) mRNA expression was determined in serial endomyocardial biopsies during the first year after transplantation. Patients with high levels of aFGF mRNA and elevations after the early posttransplant period had significantly more severe CAV than patients with low aFGF and no late elevations.

CONCLUSIONS

Parenchymal aFGF expression varies between patients and in the same patient over time and correlates with development of CAV.

Reoperation after esophageal replacement in childhood

BACKGROUND

Esophageal replacement is associated with significant morbidity that may lead to operative interventions. This study reviews the management and outcome of children who underwent reoperation after esophageal replacement.

METHODS

Eighteen patients who underwent esophageal replacement from 1985 to 1997 were reviewed retrospectively. Ten patients underwent reoperation. Patient management, perioperative morbidity, and the dietary intake at follow-up were recorded for each patient.

RESULTS

Of the reoperated patients, 7 had esophageal atresia, 2 had caustic ingestion, and 1 had achalasia. Nine patients received a colon interposition, and 1 received a reverse gastric tube as the initial esophageal replacement. Seven patients required revision of the anastomoses. Three patients required complex esophageal reconstruction: 1 underwent gastric transposition, 1 underwent free jejunal graft, and 1 underwent gastric transposition combined with free jejunal graft. Seven patients were eating well at follow-up. Two patients still required partial gastrostomy tube feeding. One patient died 6 months postoperatively from aspiration pneumonia.

CONCLUSIONS

Esophageal replacement continues to be a challenging operation associated with significant complications. Most reoperative procedures were directed toward strictures and persistent fistulae. Complete graft failure can be managed by gastric transposition or free jejunal graft. Despite the perioperative morbidity, most patients have good functional outcome.

Simplifying the Waterston's stratification of infants with tracheoesophageal fistula

The survival of infants with tracheoesophageal fistula was stratified by David J. Waterston et al. in 1962. This classification has been used as a guide to direct the timing of operative intervention in these infants. This study examines the current applicability of this classification system. The hospital records of 64 infants with esophageal atresia and/or tracheoesophageal fistula were reviewed. The survival rate was analyzed as a function of the infants' risk stratification, birth weight, and additional anomalies. Twenty-three infants were in Waterston Group A, 20 infants in Group B, and 21 infants in Group C. The survival of all infants was 81 per cent. Six infants died after recognition of severe anomalies and withdrawal of care, four infants died of cardiopulmonary arrest, and two infants died of sepsis. The survival of infants in both Groups A and B was 100 per cent, in contrast to 43 per cent survival in Group C. Only infants who weighed <1800 g or had severe additional anomalies were at risk of dying. Therefore, the classification of infants with esophageal atresia and/or tracheoesophageal fistula may be simplified by combining Waterston's Groups A and B into a single risk stratum.

Effects of intraabdominally insufflated carbon dioxide and elevated intraabdominal pressure on postoperative gastrointestinal transit: an experimental study in mice

BACKGROUND/PURPOSE

Postoperative ileus after abdominal operations is thought to be related to the degree of surgical trauma, and it has been shown that the simple act of opening the peritoneum can decrease gastrointestinal motility. Accordingly, some investigators have shown a reduction in the duration of postoperative ileus after laparoscopic procedures. It is not clear, however, if this reduction is secondary to less manipulation of the viscera or to the lack of an abdominal incision. The aim of this study was to determine the effect of intraabdominal insufflation with CO2 on postoperative gastrointestinal transit.

METHODS

Twenty-eight male mice weighing between 25 and 30 g were divided randomly into 4 groups: Control (unoperated), Incision (conventional laparotomy), Cecal (laparotomy plus cecal manipulation), and Insufflation (abdominal insufflation with CO2). Postoperative gastrointestinal motility was assessed by weighing total fecal output over the first 15 postoperative hours.

RESULTS

Fecal pellet output over 15 hours in the untreated control group was 1.20 +/- 0.12 g. In mice subjected to peritoneal incision alone, fecal pellet output was significantly decreased to 0.82 +/- 0.11 g (P < .05). However, in mice subjected to abdominal insufflation with CO2, fecal pellet output was not significantly different from untreated controls (1.2 +/- 0.05 g; not significant). Fecal pellet output was markedly reduced by incision combined with cecal manipulation (0.24 +/- 0.02 g, P < .01).

CONCLUSIONS

The current study findings show that abdominal insufflation, in a procedure similar to that used during laparoscopic surgery, had no measurable effect on gastrointestinal transit in awake mice. This suggests that the lack of an abdominal incision can contribute to a reduced postoperative ileus after abdominal surgery.

The influence of gestational age and mode of delivery on infants with gastroschisis

BACKGROUND/PURPOSE

It has been proposed that preterm and prelabor cesarean section may improve the outcome of infants with gastroschisis. The purpose of this study is to examine the impact of gestation and delivery method on infants with gastroschisis.

METHODS

The medical records of 60 infants with gastroschisis treated at a tertiary care center from 1985 through 1995 were reviewed retrospectively. The gestational age, the mode of delivery, the type of operative repair, and the length of hospital stay were recorded for each patient.

RESULTS

Infants born vaginally were more likely to require silo stage repair than those delivered by cesarean section (21 of 29 v. 11 of 31, P<.01). Infants born vaginally also had longer hospital stay than those delivered by cesarean section (53 v. 39 days, P = .19). Infants born before 33 weeks' of gestation stayed longer in the hospital than those born after 33 weeks. After 33 weeks' gestation, infants had similar hospital stay regardless of the gestational age.

CONCLUSIONS

Cesarean section delivery was beneficial for infants with gastroschisis. Preterm delivery did not shorten the length of hospital stay. The role of elective cesarean section delivery at term should be considered for infants with gastroschisis diagnosed antenatally.

Comparison of intratracheal pulmonary ventilation with hybrid intratracheal pulmonary ventilation in a rabbit model of acute respiratory distress syndrome by saline lavage

We compared different hybrid mode ITPV (h-ITPV) flow rates, and h-ITPV with intratracheal pulmonary ventilation (ITPV) with respect to CO2 clearance and oxygenation. Surfactant deficiency was induced in six adult rabbits with saline lavage. The study consisted of three phases. Phase 0: Stabilization on conventional mechanical ventilation (CMV). Phase I: Bias flow initiated at same pressure and respiratory rate as Phase 0. Flow rates of 25%, 50%, 75% h-ITPV, and ITPV were initiated. Animals were transitioned from CMV to 25% h-ITPV proceeding sequentially to ITPV or vice versa. Phase II: Animals were returned to CMV. Statistical analysis included the two-way analysis of variance (ANOVA) and repeated measures ANOVA with Tuckey's test. No difference in PaCO2 was observed among all h-ITPV flow rates or between h-ITPV and ITPV. After bias flow was introduced (transition from Phase 0 to Phase I), PaCO2 decreased by 37%. PaCO2 increased by 119% during Phase II. Oxygenation improved in all animals, particularly in those transitioned to 25% h-ITPV and proceeding to ITPV. No difference in CO2 clearance between ITPV and h-ITPV was observed. Even at low bias flows, excellent CO2 clearance was achieved. Oxygenation was superior when animals were transitioned from CMV to h-ITPV. Hybrid-ITPV offers some advantages over ITPV and may represent a powerful tool in the management of acute respiratory distress syndrome (ARDS).

Inflammatory myofibroblastic tumour of the breast: report of a case with giant vacuolated cells

Inflammatory myofibroblastic tumours (IMTs) or inflammatory pseudo-tumours are uncommon lesions of unknown aetiology. The majority of the cases are reported in the lungs of young patients. Extra-pulmonary anatomic locations include the abdomen and pelvis, but rare cases have been described in the breast. We describe an IMT in an 86-year-old female, presenting as a well-circumscribed palpable mass in the left breast. Histologically the remarkable feature was the presence of giant vacuolated cells intermixed with spindle cells and a prominent plasma cell infiltrate immersed in a fibrous hyalinized stroma. Immunohistochemical and electron microscopy studies demonstrated the myofibroblastic nature of the giant vacuolated cells and the spindle cells, and the polyclonal nature of the plasma cells. The morphologic and immunohistochemical findings supported the diagnosis of IMT. The biological behaviour of IMT in this age group is unknown and surgical excision with close mammographic follow-up is considered to be appropriate treatment for this lesion in the breast.

Pigmented schwannoma of the ventral spinal cord

Pigmented schwannomas of the spinal canal are rare entities. We present a case of such in an unusual, ventral intradural, extramedullary location in a 27-year-old man. Imaging and histopathologic findings, including electron microscopy, showed an intradural, extramedullary pigmented schwannoma, densely adherent to the leptomeninges of the anterior median septum. This lesion is demonstrative of the neuroectodermal origin of these lesions and represents a rare location of these tumors.

Metastatic sites in stage IV and IVS neuroblastoma correlate with age, tumor biology, and survival

PURPOSE

The goal of this study was to determine the incidence of metastatic sites in neuroblastoma and the extent to which metastatic sites correlate with age, tumor biology, and survival.

PATIENTS AND METHODS

All 648 patients with stage IV and IVS neuroblastoma registered on Children's Cancer Group protocols 3881 and 3891 were analyzed. Metastatic site data were provided by treating institutions and reviewed in patients with central nervous system (CNS), intracranial, lung, or "other" metastases.

RESULTS

The incidence of metastatic sites at diagnosis was 70.5% in bone marrow, 55.7% in bone, 30.9% in lymph nodes, 29.6% in liver, 18.2% in intracranial and orbital sites, 3.3% in lung, and 0.6% in CNS. Event-free survival (EFS) was decreased in patients with bone, bone marrow, CNS, intracranial/ orbital, lung, and pleural metastases, and improved in those with liver and skin metastases. In infants, MYCN amplification and unfavorable Shimada histopathology correlated with increased frequencies of bone and intracranial or orbital metastases. In older patients, MYCN amplification correlated with increased frequencies of intracranial or orbital, liver, and lung metastases. Multivariate analysis revealed that metastatic site is not an independent prognostic factor.

CONCLUSIONS

Metastatic pattern in neuroblastoma differs with age and correlates with tumor biological features and EFS. These correlations could reflect changes in host or tumor biological features with age resulting in differences in metastatic capacity or tumor affinity for specific sites.

Antireflux surgery in children under 3 months of age

PURPOSE

The aim of this study was to analyze the indications and results of fundoplication in 110 infants under 3 months of age.

METHODS

A retrospective review was conducted on the charts of all infants operated on for gastroesophageal reflux disease (GERD) at the UCLA Medical Center from January 1980 to December 1997. There were 59 boys and 51 girls. Recurrent emesis was the indication for operation in 62 of 110 infants, and respiratory symptoms in 85 of 110, with 54 of 110 having both. Neurological impairment was present in 32%. Prematurity was present in 21%; 35% had associated anomalies. Overall, 81 of 110 infants (73.6%) had one or more associated major malformations or disorders. Reflux was confirmed by upper gastrointestinal series findings in 63 of 78, esophageal pH monitoring in 60 of 62, and endoscopy in five of seven.

RESULTS

Mean age at operation was 1.8+/-0.1 months and mean weight was 3,686+/-90.2 g. A Nissen fundoplication was performed on 104 children, and six underwent a Thal procedure. Thirty-one had a gastric emptying procedure for delayed gastric emptying. Complications occurred in 7 infants. Emesis was controlled in 57 of 62 patients, aspiration in 38 of 48, and apneic spells in 54 of 57. Follow-up greater than 6 months was available for 73 patients. There were nine late deaths, all related to severe associated malformations. Seven patients required a redo fundoplication for recurrent reflux.

CONCLUSIONS

Nissen fundoplication can be performed safely in symptomatic infants under 3 months of age with low mortality and morbidity rates and with resolution of the presenting symptoms in 79% of infants.

Current aspects of biology, risk assessment, and treatment of neuroblastoma

Neuroblastoma is one of the most intensely studied solid malignancies that affect the pediatric age groups; its clinical presentation, treatment strategies and ultimate prognosis vary greatly. The biologic and genetic character of each tumor has an important impact on disease behavior, and clinical staging now incorporates these factors to generate an overall therapy plan. The clinical presentation of neuroblastoma is related to primary tumor location, production of metabolically active substances, and the presence of metastatic disease. There are also prognostically important associated syndromes including opsoclonus-myoclonus, Horner's syndrome, neurofibromatosis, and a variety of other neurocristopathies. The histologic features of the tumor are of prognostic significance and are utilized in treatment stratification. The International Neuroblastoma Staging System (INSS) has unified classic clinical staging. Features at diagnosis and those determined by initial operation are combined with biologic prognostic factors to achieve risk group assignment for virtually all patients. There are groups of children in which limited therapy is curative and intermediate-risk situations where standard multimodality treatment provides favorable outcomes. Unfortunately, there are many patients with high-risk disease that require intensive strategies, but success is still limited. It is in these most resistant patients that innovative approaches are being undertaken and novel strategies are being investigated.

Occult breast carcinoma presenting as an axillary mass

Breast carcinoma presents rarely (<5% of cases) as an axillary mass without an obvious primary tumor. The value of mammography in detecting an occult breast carcinoma is low, with a sensitivity of 29 per cent and specificity of 73 per cent. MRI and positron emission tomography (PET) are potentially more sensitive in this setting. We present a case recently seen at the Vanderbilt University Hospital, a 63-year-old woman with a 2-cm painless mass in the right axilla. Mammography was negative, and fine needle aspiration revealed atypical cells suspicious for malignancy. An excisional biopsy of the right axillary lymph node revealed metastatic adenocarcinoma, most likely breast primary. A PET showed increased uptake of 18-fluorodeoxyglucose and 99m Technetium in the right axilla and the right lateral breast. The patient underwent right modified radical mastectomy. The final pathological report revealed a 0.9-cm primary tumor in the upper inner quadrant of the breast and 1 of 41 nodes positive for tumor. This case confirms that mammography has low sensitivity in identifying the primary tumor in occult breast carcinoma and illustrates the usefulness of PET in identifying the primary tumor. We advocate an aggressive approach to evaluation of the breast in women presenting with metastatic adenocarcinoma in the axillary nodes. This evaluation should include clinical examination and mammography in all cases, and PET and MRI in selected cases. PET and MRI may be particularly useful when considering a breast-conserving surgical procedure.

Gastric emptying procedures decrease the risk of postoperative recurrent reflux in children with delayed gastric emptying

PURPOSE

Although several centers often perform gastric emptying procedures (GEP) together with fundoplication for gastroesophageal reflux (GER) and delayed gastric emptying (DGE), the benefit of GEP is controversial. The present study addresses the question of whether adding a GEP in children with preoperatively diagnosed GER and DGE affects the recurrence rate of GER after Nissen fundoplication (NF).

METHODS

A retrospective chart review was performed on all children under the age of 16 years, operated on for GER from 1980 to 1997, who had a preoperative diagnosis of DGE, and at least 6 months of follow-up. Gastric retention of more than 50% of a radiolabeled meal at 90 minutes was considered DGE. Recurrent reflux was defined as reappearance of GER symptoms, confirmed by postoperative esophagram or 24 hours of pH monitoring.

RESULTS

Of the 183 patients with DGE, 92 were available for long-term follow-up. Of these, 20 had no gastric emptying procedure performed (no-GEP group) and 72 had a GEP performed together with an NF (GEP group). Groups were comparable as to age at operation, mean follow-up time, male to female ratio and prevalence of associated anomalies. A higher prevalence of neurological impairment (NI) was present in the GEP group (48.6% v20.0%). Mean preoperative gastric retention was significantly higher in the GEP group (69.9 +/- 1.3%) than in the no-GEP group (61.4 +/- 2.2%). No complications resulted from the GEP. Recurrent reflux rate was 18.1% in the GEP group (13 of 72) versus 35.0% (7 of 20) in the no-GEP group. Actuarial analysis disclosed a marginally significant difference in the rate of recurrent reflux between the groups (P = .057) and estimation of the relative risk showed a 1.94 increase of recurrent reflux risk in the no-GEP (0.89<RR<4.20).

CONCLUSIONS

Children with DGE, who did not have GEP, had twice the frequency of recurrent reflux as those who had a GER Preoperative screening for DGE, as well as operative correction of DGE at the time of fundoplication, is therefore recommended.

Surgical ligation of patent ductus arteriosus in very low birth weight infants: is it safe?

We evaluated the outcome of a combined medical and surgical treatment of patent ductus arteriosus (PDA) in newborns weighing less than 1500 g. Charts were retrospectively reviewed for 76 newborns with a PDA between 1993 and 1997. Thirteen infants had pre-existing conditions prohibiting the use of indomethacin; eight were managed surgically, five medically. The remaining 63 infants received indomethacin therapy. Thirty-two medical failures occurred, requiring surgical ligation of the PDA. Those requiring surgery had a lower average birth weight (847 versus 997 g) and gestational age (26 versus 28 weeks; P < 0.05). Indomethacin treatment was successful in 27 infants. There were only three operative complications: a small pneumothorax, wound bleeding, and a small aortic tear. All recovered uneventfully and no deaths were attributable to the surgical procedure itself. There was no difference in the incidence of respiratory distress syndrome, duration of intubation, sepsis, neonatal enterocolitis, renal dysfunction, bleeding disorders, or intraventricular hemorrhage among both groups. Surgical ligation of a PDA is associated with a high success rate, a low incidence of complications, and no additional morbidity than indomethacin alone. We propose that surgical ligation should be regarded as a first line therapy for very small premature infants who are at higher risk of medical failure.

A prospective randomized trial of urokinase as an adjuvant in the treatment of proven Hickman catheter sepsis

BACKGROUND/PURPOSE

Chronic vascular access catheters have become an important adjunct to the treatment of children with complex medical diseases, particularly malignancy. One of the major complications of chronic venous access devices is bacterial infection of the catheter site and bloodstream. Infusion of systemic antibiotics directly into the catheter has been the standard initial therapy with failure leading to catheter removal and replacement. It has been suggested by a number of investigators that the addition of urokinase as a thrombolytic agent to lyse any accumulated thrombus or fibrin would increase the successful catheter clearance by antibiotics. This study was designed as a prospective, randomized trial to compare treatment of children with positive catheter blood cultures with either antibiotics alone or in combination with urokinase 5,000 U boluses 12 and 24 hours after study entry.

METHODS

A total of 63 patients were entered in the study. Thirty-three received antibiotics and urokinase, and 30 received antibiotics alone.

RESULTS

A total of 45 catheters (71%) were cleared of infection and salvaged. Treatment failures leading to catheter removal occurred in 9 of 33 in the experimental group and 9 of 30 in the control population (no significant difference).

CONCLUSIONS

Urokinase could not be shown to act as an adjuvant in the clearance of infection from chronic central venous access catheters that had no evidence of clot or thrombus. This study required the performance of a dye study and excluded any patient with a known thrombus. This conclusion must therefore be limited to patients with no evidence of a clot or fibrin sheath.

Successful treatment of stage III neuroblastoma based on prospective biologic staging: a Children's Cancer Group study

PURPOSE

To identify a biologically favorable and unfavorable subset of patients with Evans stage III neuroblastoma and to determine whether treatment stratification would improve the event-free survival (EFS) for high-risk patients and maintain excellent EFS for the lower-risk patients.

PATIENTS AND METHODS

Risk stratification was performed by age, MYCN gene copy number, Shimada histopathologic classification, and serum ferritin level. Lower-risk patients were treated on the less intensive Children's Cancer Group (CCG)-3881, whereas high-risk patients were treated on CCG-3891, which included more intensive multimodality therapy and, in some cases, autologous bone marrow transplantation (ABMT).

RESULTS

Of 228 Evans stage III patients entered onto the study, 92% also met the definition of International Neuroblastoma Staging System (INSS) stage 3. One hundred forty-three patients met the lower-risk criteria, which included 89 patients less than 1 year of age and 54 patients 1 year of age or greater, and favorable biology, whereas 85 patients were 1 year of age or greater and biologically unfavorable. Biologically unfavorable patients 1 year of age or greater who underwent gross surgical resection had improved survival, whereas the outcome of infants or biologically favorable older patients did not change according to resection. The EFS rate at 4 years was 100% for the patients with favorable biology of any age, 90% for those less than 1 year of age but with at least one unfavorable characteristic, and 54% for Evans stage III patients 1 year of age or greater with unfavorable biology. Age, ferritin level, MYCN copy number, Shimada histopathology, primary site, and intraspinal extension were significant univariate prognostic factors for all patients, but only MYCN copy number and age were independent factors in multivariate analyses.

CONCLUSION

The excellent survival of the biologically favorable group and the historically improved EFS of the biologically unfavorable group suggest that biologic staging should be used to define the prognosis and treatment of stage III neuroblastoma.

Congenital diaphragmatic hernia survival and use of extracorporeal life support at selected level III nurseries with multimodality support

BACKGROUND

Congenital diaphragmatic hernia (CDH) has been cited to have a mortality rate of 50%. There have been multiple studies at individual institutions demonstrating potential benefits from various strategies including extracorporeal life support (ECLS), delayed repair, and lower levels of ventilator support. There has been no multicenter survey of institutions offering these modalities to describe the current use of ECLS and survival of these infants. In addition, the relationship between the number of patients with CDH managed at an individual institution and outcome has not been evaluated.

METHODS

We queried 16 level III neonatal intensive care centers on the use of ECLS and survival of infants with CDH who were treated during 2 consecutive years (1993 to 1995). Data are presented as mean +/- SEM, median, and range.

RESULTS

Data were collected on 411 patients. Of these, 71% +/- 8% were outborn and 8% +/- 3% were considered nonviable. Overall survival of CDH infants was 69% +/- 4% (range, 39% to 95%). The survival rate of infants on ECLS was 55% +/- 4%, whereas survival of infants not requiring ECLS was significantly increased at 81% +/- 5% (p = 0.005). The mean rate of ECLS use was 46% +/- 2%. There was no correlation between the number of cases per year at an individual institution and overall survival, ECLS survival, or ECLS use (r = 0.341, 0.305, and 0.287, respectively). There was also no correlation between case volume at an individual institution and ECLS survival (r = 0.271).

CONCLUSIONS

The current survival rate and rate of ECLS use in infants with CDH at level III neonatal intensive care units in the United States are 69% +/- 4% and 46% +/- 2%, respectively. There is no correlation between the yearly individual center experience with managing CDH and rate of ECLS use or outcome.

First Observations of Laser-Excited Hg3 and Hg2RG Spectra in a Supersonic Expansion Beam

Triatomic van der Waals complexes of mercury have been observed in a supersonic expansion beam crossed with a laser beam to produce excitation and fluorescence spectra. The expansion beam consisting of mercury and a (noble) carrier gas (RG) was excited in three separate spectral regions: in the vicinity of the Hg 2537 A intercombination line, near the (forbidden) Hg 6(3)P2 <-- 6(1)S0 atomic transition (2200-2290 A), and in the region of the Hg2 G0(+)u <-- X0(+)g transition (1975-2080 A). The resulting spectra, which were recorded in the spectral range 1900-6000 A, contained, in addition to the known Hg, Hg2, and HgRG components, new absorption and fluorescence bands that are ascribed to Hg2RG and Hg3 complexes. Copyright 1998 Academic Press. Copyright 1998Academic Press

Accelerated arteriosclerosis after transplantation: the possible role of calcium channel blockers

The major factor limiting the long-term success of cardiac transplantation is the development of accelerated arteriosclerosis that occurs in the coronary arteries of the cardiac allograft. Transplant arteriosclerosis is characterized by diffuse, uniform, concentric narrowing of the artery by a proliferative, fibrocellular intima. The etiology of transplant arteriosclerosis is thought to be immune-mediated, and endothelial cells, smooth muscle cells, and inflammatory cells participate in the progression. Based on data derived from studies of conventional atherosclerosis, in which calcium channel blockers (CCBs) have demonstrated beneficial effects, preliminary studies designed to determine if CCBs might affect transplant arteriosclerosis similarly have been performed in animal models as well as in a limited number of cardiac transplant patients. Amlodipine suppressed transplant arteriosclerosis in one animal study, while diltiazem preserved vasodilatory responses in another animal study. Small prospective trials and retrospective studies in humans have shown that CCBs have a favorable effect on the development of transplant arteriosclerosis. While no work has been directed specifically at determining the mechanisms by which CCBs might prevent transplant arteriosclerosis, there are several likely candidates. These include preservation of endothelial function, suppression of smooth muscle cell migration and proliferation, production of extracellular matrix, and regulation of lipid metabolism and certain components of the immune system.

Contractile failure in chronic doxorubicin-induced cardiomyopathy

The mechanisms for the progression of the anthracycline-induced cardiomyopathy to contractile failure has not been defined. In vitro, doxorubicin (DOX) appears to modify calcium-mediated excitation-contraction coupling, which depresses cardiac contractility. This study characterizes the onset of contractile failure associated with the development of DOX-induced cardiomyopathy. Rabbits were treated with DOX (1 mg/kg i.v. twice weekly, 12-18 doses; DOX-treated group) and compared with a pair-fed Control group infuse with saline vehicle. The severity of the cardiomyopathy was determined by numerically-scored histopathology. Myocardial contractility was determined in thin fiber bundles from right ventricular (RV) papillary muscles and left atria that were removed and mounted on a force transducer in oxygenated Krebs-bicarbonate buffer (pH=7.4 at 30 degrees C) to record the amplitude (DT) and maximum rate (+dT/dt ) of isometric tension. Myofibrillar and calcium loading properties were determined by the calcium and caffeine-activated tension responses respectively in chemically-permeabilized fibers. With the onset of the cardiomyopathy (score <2) DT at low frequency (0.5 Hz) was depressed (0.61+/-0.01 mN/mg; n=14) compared to Control (0.93+/-0.09 mN/mg; n=15). Contractility at higher rates (1 Hz) was not different in this DOX-treated and Control groups. Maximum calcium and caffeine-activated force and the pCa to half-maximum force of permeabilized fibers were comparable in DOX-treated and Control groups. The loss of contractility of the DOX-treated group was related to reduction in sarcoplasmic reticulum calcium release channel density, as determined by Bmax for 3H-ryanodine binding in cardiac microsomal membrane fraction. Post-rest potentiation of contractility, as well as frequency-dependent (0.25-1.5 Hz) and post-extrasystolic potentiation of contractility were preserved in the DOX-treated group. In vitro, DOX depressed post-rest potentiation of contractility. Thus, the onset of contractile failure of the DOX-induced cardiomyopathy is characterized by effects consistent with disordered calcium-mediated excitation-contraction coupling and these effects are qualitatively different than in vitro effects of DOX.

Histopathology of restenosis after stenting of narrowed coronary arteries after cardiac transplantation during the teenage years

This study describes the detailed histopathologic appearance of human coronary arteries at 3 weeks, and 3 and 7 months after stent implantation in a cardiac transplant recipient. There was modest arterial injury associated with stent implantation, and immunocytochemistry staining provided evidence that a proliferative response from the adventitia contributes to neointimal hyperplasia.

Length of transplanted small bowel required for adequate weight gain in rats

Progress has been made toward developing a clinically successful small-bowel transplant procedure, but there has been little research concerning the functional aspects of the transplanted small bowel. Using a rat model, our study examined the length of transplanted small bowel required to provide adequate weight gain. The rats were divided into six groups; groups 1 and 2 were considered controls. Group 1 (n = 6) underwent a gastrostomy. Group 2 (n = 3) underwent a jejunoile-ectomy followed by re-establishment of intestinal continuity and anastomosis of the native proximal small bowel to an abdominal stoma and the distal portion to the ascending colon. Groups 3 (n = 5), 4 (n = 4), 5 (n = 5), and 6 (n = 4) underwent small-bowel transplantation, receiving 100%, 50%, 25%, and 15% transplants, respectively. The donor small-bowel anastomoses were the same as the native small-bowel anastomoses in group 2. All of the rats began to produce stool within 4 days of becoming dependent upon the transplanted small bowel. By the end of postoperative week 4, there was no significant difference between the percentages of preoperative body weight in groups 1-4 (range 125.7%-130.0%). Although the weight gain in group 5 was significantly less than that in groups 1-4 (P < 0.05), it was adequate (111.8%); group 6 animals lost weight (94.7%). It is concluded that a 50% or more small-bowel transplant with or without an ileocecal valve provides ample weight gain; minimally adequate weight gain is achieved by a 25% transplant without an ileocecal valve; and the graft begins to function soon after transplantation.

Prospective, randomized evaluation of the efficacy of fibrin sealant as a topical hemostatic agent at the cannulation site in neonates undergoing extracorporeal membrane oxygenation

BACKGROUND

The topical hemostatic effect of fibrin sealant that has been solvent/detergent treated and plasminogen depleted was evaluated in a multicenter prospective, randomized controlled study at the cannulation site wound of infants undergoing extracorporeal membrane oxygenation (ECMO).

METHODS

The test group received standard cauterization and Fibrin sealant, while the control group was given cauterization alone to control hemostasis at this site. Efficacy data were available on 173 randomized study subjects of whom 149 met study entry criteria. All were managed according to standard ECMO practice.

RESULTS

Fibrin sealant reduced the risk of bleeding, was associated with less shed blood, and was associated with shorter duration of hemorrhage. Further, control infants showed an increased bleeding risk with less depressed fibrinogen levels and prothrombin time elevations >18 seconds prior to ECMO.

CONCLUSION

Fibrin sealant is useful as a topical hemostatic agent in patients with coagulopathy not responding to standard surgical techniques.