Metastasectomy for melanoma in the VATS era

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Background: The role for metastasectomy in the setting of metastatic melanoma remains ill-defined. The aim of this study is to evaluate resection of limited metastases in the setting of melanoma comparing VATS and open approaches, specifically looking at perioperative morbidity and survival. Methods: All patients undergoing metastasectomy for melanoma with curative intent between January 1, 2001 and September 30, 2007 were included. Data was collected retrospectively from the UPMC tumor registry and chart review. Differences between groups were compared with the student's t-test. Results: Of 43 patients undergoing metastasectomy for melanoma, 31 patients were resected with intent to cure (16 VATS, 15 open). Complications were similar between the VATS (12%) and open (13%) groups. There were no perioperative deaths in either group. The median survival in the VATS group was 20.7 months, compared to 26.5 months in the open group (p = 0.17). Importantly, the VATS patients more frequently underwent resection of smaller, peripheral lesions via wedge resection (81%) and only 2 patients (13%) underwent lobectomy. Conversely, patients undergoing open procedures were more likely to have larger, more central lesions and undergo anatomic resections. There were 9 (60%) lobectomies, 3 (20%) segmentectomies 1 (7%) en bloc resection and only 2 (13%) wedge resections in the open group. Conclusions: Metastasectomy for metastatic melanoma in the thoracic cavity can be performed safely by a VATS or open approach. The two approaches have comparable morbidity, mortality and survival outcomes. Careful patient resection remains the hallmark of care in identifying appropriate candidates for metastasectomy. In the setting of patients with short life-expectancy, it may be advantageous to employ a VATS approach when possible to preserve quality of life while achieving similar oncologic outcomes to open procedures. Individuals with a radiographic indication of limited peripheral disease should be considered for a VATS approach to resection of melanoma metastases.

No significant financial relationships to disclose.

Clinical impact of age on outcomes following anatomic lung resection for stage I non-small cell lung cancer

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Background: There is an increasing body of evidence that anatomic segmentectomy may represent an equivalent approach compared to lobectomy in the management of stage I NSCLC. Comorbidities associated with age may result in improved survival with sublobar resection for stage I cancer in the elderly. We report our single institution experience with segmentectomy vs. lobectomy for stage I non-small cell lung cancer stratified by age. Methods: A total of 232 consecutive anatomic segmentectomies were performed for stage IA (n=137) or IB (n=95) NSCLC from 2002–2007. Lobectomy was performed in 594 patients for stage IA (n=297) and IB (n=295) during the same period. Results of segmental resection were compared with lobectomy, stratified by the following age groups: <60, 60–69, 70–79 and = 80. Primary outcome variables included complications, mortality, recurrence patterns, and survival. Statistical analysis included t-test and Fisher's exact test. Results: Mean age (69.9 vs. 68.2), gender distribution and tumor histology were similar between the segmentectomy and lobectomy groups. There was no significant difference in complications, mortality, recurrence, and overall survival in the younger age groups (Table). Segmentectomy was associated with reduced mortality (7.8% vs. 2.8%) and improved overall 3-year survival (p=0.02) in patients >80 years old. Conclusions: Anatomic segmentectomy can be performed with similar morbidity, mortality, recurrence, and survival compared to lobectomy in stage I lung cancer. This approach may be particularly advantageous in the elderly age group, achieving comparable oncologic outcomes with less mortality and improved overall survival.

[Table: see text]

No significant financial relationships to disclose.

Results of a randomized trial of HERMES-assisted versus non-HERMES-assisted laparoscopic antireflux surgery

BACKGROUND

Speech recognition technology is a recent development in minimally invasive surgery. This study was designed to assess the impact of HERMES on operating room efficiency and user satisfaction.

METHODS

Patients undergoing laparoscopic antireflux operations by surgeons experienced in minimally invasive surgery were randomized to HERMES-assisted or standard laparoscopic operations. The variables of interest were circulating nurse's time spent adjusting devices that are voice-controlled by HERMES, number of adjustments to devices requested, and surgeon and nurse satisfaction measured on a scale from 1 (dissatisfied) to 10 (satisfied).

RESULTS

A total of 30 cases were studied. In the non-HERMES cases, nurses were interrupted to make device adjustments an average of 15.3 times per case versus 0.33 times per case in the with-HERMES cases (p < 0.01). The interruptions during the non-HERMES cases averaged 4.35 min per case versus 0.16 min per case in the with-HERMES cases (p = 0.03). Average satisfaction scores for HERMES operations as opposed to non-HERMES operations were 9.2 versus 5.3 for nurses (p < 0.01) and 9.0 versus 5.1 for surgeons (p < 0.01).

CONCLUSIONS

Physician and nurse acceptance of HERMES was very high because of the smoother interruption-free environment.

Outcomes of minimally invasive esophagectomy (MIE) for high-grade dysplasia of the esophagus

OBJECTIVE

The management of high-grade dysplasia (HGD) of the esophagus is controversial with some clinicians advocating non-operative ablation or surveillance. Minimally invasive esophagectomy (MIE) allows re-section of the esophagus and may minimize morbidity. This report summarizes our experience with MIE for HGD.

METHODS

A retrospective review of 28 patients who underwent MIE for a pre-operative diagnosis of HGD. MIE initially involved a laparoscopic transhiatal approach (n=1), but subsequently evolved to laparoscopy with VATS mobilization (n=27) of the esophagus.

RESULTS

From August 1996 to March 2001, 28 patients underwent MIE. There were 23 males and five females; median age was 61 (40-78) years. Median hospital stay was 5 (3-20) days and ICU stay was 1 (1-20) day. One patient required conversion to laparotomy because of dense adhesions. There were ten other patients who had successful MIE despite prior laparotomy. Median operating time was 8 (5.8-13) h. One death occurred from sepsis, pneumonia and multi-system organ failure. Complications occurred in 15 patients. In addition to the patient who died, five re-operations were required for: small bowel perforation (n=1), jejunostomy leak (n=1), pyloric dilation for gastric outlet obstruction (n=1), cholecystectomy (n=1), incision and drainage of an abdominal abscess (n=1). Final pathologies were HGD (n=17), in situ cancer (n=6) and invasive cancer (n=5). At a median follow-up of 13 (2-41) months all hospital survivors are alive and free of disease.

CONCLUSIONS

This report confirms the risk of occult cancer in patients with HGD (39% in this series) supporting the recommendation for esophagectomy. MIE can be performed with acceptable results and may minimize morbidity compared to previous reports of open esophagectomy for HGD.

Outcomes of laparoscopic Toupet compared to laparoscopic Nissen fundoplication

BACKGROUND

Recent reports suggest that partial fundoplications such as the laparoscopic Toupet (LT) ultimately suffer from a higher recurrence rate compared to complete wraps such as the laparoscopic Nissen fundoplication (LNF). This article summarizes our experience with LT and LNF.

METHODS

Over a 45-month period (February 1995 to November 1998), 206 patients underwent laparoscopic antireflux operations. The LNF group included 163 patients and the LT group included 43 patients. Global quality of life was measured using the Medical outcomes short form 36 (SF36).

RESULTS

There were no differences in disease severity, except that the LT group had a higher incidence of esophageal dysmotility (37.2% 8.6%, p < 0.05). Early outcomes were similar, with no perioperative deaths and morbidity occurring in 15 (9.2%) LNF and 5 (11.6%) LT patients (p = not significant). Long-term follow-up was available in 142 patients at a mean of 19.7 months. A greater number of LT patients required proton pump inhibitors (38 vs 20%) and were dissatisfied (21 vs 7%) with their surgery (p < 0.05). SF36 physical function scores were better in the LNF group (85 vs 74; p < 0.05). Significantly more (p < 0.05) of the LT patients complained of dysphagia (34.5 vs 15%) on follow-up. There were no differences in the incidence of symptoms related to the gas-bloat syndrome. The observed differences between the LT and LNF groups did not appear to be related to differences in esophageal motility.

CONCLUSIONS

Short-term results were similar for LT and LNF, but with longer follow-up, better results were seen with LNF. Even in the setting of moderate decreases of esophageal motility, complete fundoplication yields superior results.

Outcomes after minimally invasive esophagomyotomy

BACKGROUND

Thoracic surgeons traditionally performed thoracotomy and myotomy for achalasia. Recently minimally invasive approaches have been reported with good success. This report summarizes our single-institution experience using video-assisted thoracoscopy (VATS) or laparoscopy (LAP) for the treatment of achalasia.

METHODS

A review of 62 patients undergoing minimally invasive myotomy for achalasia was performed. There were 27 male and 35 female patients. Mean age was 53 years (range 14 to 86). Thirty-seven (59.7%) had failed prior treatments (balloon dilation, botulinim toxin injection, or prior surgery). Outcomes studied were dysphagia score (1 = none, 5 = severe), Short-Form 36 quality of life (SF36 QOL) score, and heartburn-related QOL index (HRQOL).

RESULTS

Surgery included myotomy and partial fundoplication (5 VATS and 57 LAP). Mortality was zero, and complications occurred in 9 (14.5%) patients. There were 6 perforations (4 repaired by LAP and 2 open). Median length of stay was 2 days, time to oral intake was 1 day. At a mean of 19 months follow-up, 92.5% of patients were satisfied with outcome. Dysphagia scores improved from 3.6 to 1.5 (p < 0.01) but 3 patients ultimately required esophagectomy for recurrent dysphagia. HRQOL scores for heartburn and SF-36 QOL scores were comparable with control populations.

CONCLUSIONS

Minimally invasive myotomy and partial fundoplication for achalasia improved dysphagia in 92.5% of patients with heartburn and QOL scores were comparable with normal values at 19-month follow-up. The laparoscopic approach offers excellent results and was the preferred approach by our thoracic group for treating achalasia. Thoracic residency training should strive to include laparoscopic esophageal experience.

Results of expandable metal stents for malignant esophageal obstruction in 100 patients: short-term and long-term follow-up

BACKGROUND

Expandable metal stents palliate malignant dysphagia in most cases, but early complications and outcomes in long-term survivors have not been well described. This report summarizes our experience with expandable metal stents for malignant dysphagia.

METHODS

Over a 48-month period, 127 stents were placed in 100 patients with dysphagia from esophageal cancer (93%) or lung cancer. Most had undergone prior treatment. Dysphagia scores, duration of palliation, complications, and reintervention were evaluated.

RESULTS

Immediate improvement in dysphagia was observed in 85% of patients with no procedure-related deaths. Dysphagia score decreased from 3.3 before stent to 2.3 (p < 0.005). Average interval to reintervention was 80 days. In 40 patients surviving more than 120 days, 31 (78%) required reintervention. Major complications occurred in 3 patients receiving poststent chemoradiation (tracheoesophageal fistula, T1 vertebral body abscess, mediastinal abscess). Other complications included unsatisfactory deployment requiring immediate removal (3 patients), migration (11 patients), pain requiring removal (2 patients), food impaction (10 patients), and tumor ingrowth (37 patients).

CONCLUSIONS

Expandable metal stents offer excellent short-term palliation of malignant dysphagia. In long-term survivors, recurrent dysphagia requiring reintervention is common. In a small subset of patients receiving chemoradiation after stent placement, major complications were observed.

The Role of Positron Emission Tomography in Evaluating Mediastinal Lymph Node Metastases in Non–Small-Cell Lung Cancer

Positron emission tomography (PET) is a modality that differentiates malignant from benign processes based upon metabolism rather than anatomy. A number of studies have confirmed improved accuracy of PET over computed tomography (CT), but until a few recent studies, most had failed to include satisfactory histologic confirmation. The objective of this study was to compare PET and CT to histologic staging of the mediastinum in patients with non-small-cell lung cancer (NSCLC). Histologic examination of mediastinal lymph nodes (MLNs) was performed on 40 patients with NSCLC at mediastinoscopy and/or at surgical resection. PET scans were interpreted by one of two nuclear medicine physicians, blinded to histology, using CT scans for anatomic localization. CT scans were independently evaluated for mediastinal lymphadenopathy. The overall accuracy, sensitivity, and specificity of PET were 78% (31 of 40), 67% (four of six), and 79% (27 of 34), respectively. The overall accuracy, sensitivity, and specificity of CT were 68% (27 of 40), 50% (three of six), and 71% (24 of 34), respectively. PET was superior to CT at correctly identifying mediastinal nodal metastases; however, both modalities were inferior to the gold standard of surgical staging. PET is more accurate than CT in staging the mediastinum of patients with NSCLC. PET failed to identify lymph node metastasis in 33% of patients with histologically proven MLN involvement, and false positives were present in 15%. At present, mediastinoscopy should remain the standard of care for preoperative mediastinal staging for NSCLC.

Laparoscopic repair of giant paraesophageal hernia: 100 consecutive cases

OBJECTIVE

To summarize the authors' laparoscopic experience for paraesophageal hernia (PEH).

SUMMARY BACKGROUND DATA

Laparoscopic antireflux surgery and repair of small hiatal hernias are now routinely performed. Repair of a giant PEH is more complex and requires conventional surgery in most centers. Giant PEH accounts for approximately 5% of all hiatal hernias. Medical management may be associated with a 50% progression of symptoms and a significant death rate. Conventional open surgery has a low death rate, but complications are significant and return to routine activities is delayed in this frequently elderly population. Recently, short-term outcome studies have reported that minimally invasive approaches to PEH may be associated with a lower complication rate, a shorter hospital stay, and faster recovery.

METHODS

From July 1995 to February 2000, 100 patients (median age 68) underwent laparoscopic repair of a giant PEH. Follow-up included heartburn scores and quality of life measurements using the SF-12 physical component and mental component summary scores.

RESULTS

There were 8 type II hernias, 85 type III, and 7 type IV. Sac removal, crural repair, and antireflux procedures were performed (72 Nissen, 27 Collis-Nissen). The 30-day death rate was zero; there was one surgery-related death at 5 months from a perioperative stroke. Intraoperative complications included pneumothorax, esophageal perforation, and gastric perforation. There were three conversions to open surgery. Major postoperative complications included stroke, myocardial infarction, pulmonary emboli, adult respiratory distress syndrome, and repeat operations (two for abscess and one each for hematoma, repair leak, and recurrent hernia). Median length of stay was 2 days. Median follow-up at 12 months revealed resumption of proton pump inhibitors in 10 patients and one repeat operation for recurrence. The mean heartburn score was 2.3 (0, best; 45, worst); the satisfaction score was 91%; physical and mental component summary scores were 49 and 54, respectively (normal, 50).

CONCLUSION

This report represents the largest series to date of laparoscopic repair of giant PEH. In the authors' center with extensive experience in minimally invasive surgery, laparoscopic repair of giant PEH was successfully performed in 97% of patients, with a minimal complication rate, a 2-day length of stay, and good intermediate results.

Minimally invasive esophagectomy

BACKGROUND

Open esophagectomy can be associated with significant morbidity and delay return to routine activities. Minimally invasive surgery may lower the morbidity of esophagectomy but only a few small series have been published.

METHODS

From August 1996 to September 1999, 77 patients underwent minimally invasive esophagectomy. Initially, esophagectomy was approached totally laparoscopically or with mini-thoracotomy; thoracoscopy subsequently replaced thoracotomy.

RESULTS

Indications included esophageal carcinoma (n = 54), Barrett's high-grade dysplasia or carcinoma in situ (n = 17), and benign miscellaneous (n = 6). There were 50 men and 27 women with an average age of 66 years (range 30 to 94 years). Median operative time was 7.5 hours (4.5 hours with > 20 case experience). Median intensive care unit stay was 1 day (range 0 to 60 days); median length of stay was 7 days (range 4 to 73 days) with no operative or hospital mortalities. There were four nonemergent conversions to open esophagectomy; major and minor complication rates were 27% and 55%, respectively.

CONCLUSIONS

Minimally invasive esophagectomy is technically feasible and safe in our center, which has extensive minimally invasive and open esophageal experience. Open surgery should remain the standard until future studies conclusively demonstrate advantages of minimally invasive approaches.

Total Videothoracoscopic Lobectomy Versus Open Thoracotomy for Early-Stage Non–Small-Cell Lung Cancer

Lobectomy remains the standard procedure for early-stage non small-cell lung cancer (NSCLC). Advances in minimally invasive surgery allow lobectomy to be performed by videothoracoscopy (VATSLOBE). The objective of this study was to compare open thoracotomy (OPENLOBE) to VATSLOBE in the treatment of early-stage NSCLC. A retrospective review over a 6-year period at a single tertiary care center identified 31 patients treated by VATSLOBE. A comparison was made with 31 patients undergoing OPENLOBE during the same time period. The cases were matched for age, pulmonary function testing, tumor size, and comorbidities. The VATSLOBE technique was carried out using four 1 cm thoracoports, one of which was enlarged to a 4-6 cm access incision for lobe retrieval. OPENLOBE was performed by standard posterolateral thoracotomy. The VATSLOBE group had a longer operative time (214.03 min) compared to OPENLOBE (140.67 min). There was no difference in the extent of lymph node dissection or in morbidity between the two groups. VATSLOBE patients had their chest tubes removed earlier (4.77 vs. 8.16 days) and stayed in the hospital for a shorter time (7.07 vs. 11.94 days) compared to OPENLOBE patients. In this retrospective review, lobectomy performed by the videothoracoscopic approach was comparable to OPENLOBE in terms of lymph node dissection, morbidity, and long-term survival. VATSLOBE had the advantages of a shorter hospital stay and fewer days with a chest tube. Minimally invasive surgery for early-stage lung cancer should be further investigated in multi-institutional controlled trials.

Endoscopic photodynamic therapy for obstructing esophageal cancer: 77 cases over a 2-year period

BACKGROUND

Photodynamic therapy (PDT) is an alternative treatment option for the palliation of obstructive esophageal cancer. We report our experience with PDT for patients presenting with inoperable, obstructing, or bleeding esophageal cancer.

METHODS

Seventy-seven patients with inoperable, obstructing esophageal cancer were treated with PDT from November 1996 to July 1998. Photofrin (1.5-2.0 mg/kg) was administered, followed by endoscopic light treatment (630 nm red dye laser) at 48 h. Dysphagia score (1 for no dysphagia to 5 for complete obstruction), dysphagia-free interval, and patient survival were assessed.

RESULTS

Seventy-seven patients underwent 125 PDT courses. The mean dysphagia score at 4 weeks after PDT in 90.8% of the patients improved from 3.2 +/- 0.7 to 1.9 +/- 0.8 (p < 0.05). PDT adequately controlled bleeding in all six patients who had bleeding. The most common complications after the 125 PDT courses were esophageal stricture (4.8%), Candida esophagitis (3.2%), symptomatic pleural effusion (3.2%), and sunburn (10.0%). Twenty-nine patients (38%) required more than one PDT course, and seven patients required placement of an expandable metal stent for recurrent dysphagia. The mean dysphagia-free interval was 80.3 +/- 58.2 days. The median survival was 5.9 months.

CONCLUSIONS

Photodynamic therapy is a safe and effective treatment for the palliation of obstructing and bleeding esophagus cancer.

Thoracoscopic and laparoscopic esophagectomy

Esophagectomy is both complex and challenging, and it may be associated with significant morbidity and mortality. With improvements in instrumentation and increasing experience with laparoscopic and thoracoscopic techniques, minimally invasive approaches to esophagectomy are being explored to determine feasibility, results, and potential advantages. Most of this experience has been with case studies or small series, with many surgeons using thoracoscopy in combination with standard laparotomy. Many of the patients have been carefully selected for these procedures because they have small tumors or high-grade dysplasia. Our technique for esophagectomy has evolved from a laparoscopic transhiatal approach to a combined laparoscopic and thoracoscopic approach. Our experience with this procedure has increased, and now we offer this approach to the majority of patients with resectable cancers. We review our operative technique and the results of surgery in our first 50 patients who underwent minimally invasive esophagectomy for cancer or high-grade dysplasia.

M1a/M1b esophageal carcinoma: clinical relevance

OBJECTIVE

The 1997 staging system for esophageal carcinoma subdivides distant metastatic disease (M1) into M1a (nonregional lymph node metastases) and M1b (other metastases). This study evaluates the relevance of this classification.

METHODS

One hundred forty patients were identified with M1 disease, 36 (26%) M1a and 104 (74%) M1b. The histologic type was adenocarcinoma in 118 (84%), squamous cell in 18 (13%), and adenosquamous in 4 (3%), with a similar distribution for M1a and M1b (P =.3). Forty-five underwent surgery, 28 (78%) with M1a disease and 17 (16%) with M1b disease (P <.001). Chemotherapy and/or radiation therapy was given to 33 (73%) surgical patients and 63 (66%) nonsurgical patients (P =.4), 28 (78%) with M1a disease and 68 (66%) with M1b disease (P =.17).

RESULTS

Median and 5-year survivals were 11 months and 6% in patients with M1a disease and 5 months and 2% in those with M1b disease (P =.001). Surgery provided no advantage in M1b (P =.6) or M1a disease (P =.2). Multivariable analysis demonstrated that patients with M1b disease had 1.8 times the mortality risk of those with M1a disease (CI 1.2-2.7, P =.004), and patients without chemotherapy and/or radiotherapy had 2.2 times the mortality risk of those with chemotherapy and/or radiotherapy (CI 1.5-3.2, P <.001). Despite the prevalence of surgery in patients with M1a disease, the analysis suggests that M1a and use of chemotherapy and/or radiotherapy, rather than surgery, account for the small, clinically unimportant differences in survival.

CONCLUSIONS

We conclude that (1) although there are statistically significant survival differences between M1a and M1b disease, these differences are not clinically important; (2) chemotherapy and/or radiotherapy is associated with a modest survival benefit; and (3) surgery offers no survival advantage.

H2O2 mediates O2 toxicity in cultured fetal rat distal lung epithelial cells

It is unknown which of the reactive oxygen species is primarily responsible for the cytotoxicity of 95% O2 for rat distal fetal lung epithelial cells in vitro. Incubation of cells with 25 U/ml polyethylene glycol (PEG)-conjugated SOD and 50 U/ml PEG-catalase, but not PEG-SOD or SOD mimics alone, significantly reduced 95% O2-mediated cytotoxicity. Liposome-entrapped catalase, without SOD, also significantly reduced 95% O2-mediated cytotoxicity. Increased formation of lipid hydroperoxides, as assessed by the formation of 8-isoprostane and aldehydes, was attenuated by both 100 microM Trolox, a vitamin E analogue, and by 5 microM U74389G, an amino steroid. Trolox, but not U74389G, prevented an increase in cell-derived H2O2, hydroxyl radical and 95% O2-mediated cytotoxicity. An increase in hydroxyl radical formation, but not cell death, observed in 95% O2, was prevented by 0.1 microM phenanthrolene, a cell permeant iron chelator. DNA extracts of rat distal fetal lung epithelial cells maintained under serum-free conditions had an electrophoretic pattern consistent with some degree of apoptosis. However, no increase in laddering was seen with exposure to 95% O2. These data are consistent with hydrogen peroxide, but not lipid hydroperoxides or hydroxyl radical, being a critical effector of O2-mediated necrotic cell death in distal lung epithelial cells.

Changes in structure, mechanics, and insulin-like growth factor-related gene expression in the lungs of newborn rats exposed to air or 60% oxygen

Exposure of neonatal rats to > or = 95% O2 for 2 wk, a widely used model of oxidant/antioxidant interactions in neonatal lung injury, results in arrested lung growth without the dysplastic lesions observed in chronic human neonatal lung injury. To determine whether dysplastic lung cell growth would be seen at lesser O2 concentrations, we exposed newborn rats to either 95% O2 for 1 wk followed by 60% O2 for 1 wk, or to 60% O2 for 2 wk. Exposure to 95% O2 for 1 wk profoundly inhibited lung DNA synthesis. Recovery of synthesis did not occur during the 2nd wk in 60% O2, nor were areas of dysplastic growth evident in lung tissue. In contrast, a continuous 2-wk exposure to 60% O2 resulted in a slight increase in lung weight with a significant reduction in lung volume over a range of inflation pressures. Also seen was an overall, but inhomogeneous, reduction in lung cell DNA synthesis. A preliminary analysis of affected cell types suggested that inhibition of DNA synthesis affected endothelial cells more than interstitial cells, whereas DNA synthesis increased in type II pneumocytes. Areas of reduced DNA synthesis were interspersed with patchy areas of parenchymal thickening and active DNA synthesis. These areas of parenchymal thickening, but not other areas, had increased immunoreactive IGF-I and the type I IGF receptor. These data are consistent with a direct effect of O2 on growth factor and growth factor receptor expression in causing dysplastic lung cell growth in chronic neonatal lung injury.

Lung oxidant injury in a model of lung storage and extended reperfusion

Donor lungs for transplantation are susceptible to "preservation" injury during both storage and postimplantation reperfusion. We investigated whether lung dysfunction seen after storage and reperfusion was associated with any biochemical hallmarks of direct cellular oxidant injury to lipid, protein, or DNA. Heart/lung blocks were extracted from adult rats following pulmonary vascular flush. Lungs were either perfused immediately ex vivo for 2 h with deoxygenated venous rat blood or were stored at 10 degrees C for 13 h before perfusion. Stored lungs had increased airway pressure, pulmonary vascular shunt fraction, wet/dry weight ratio, and parenchymal hemorrhage after perfusion but no change in pulmonary artery pressure compared with immediately perfused lungs. Hypothermic storage caused no biochemical changes in lung tissue. Perfusion of fresh or stored lungs resulted in lipid peroxidation and loss of nonprotein reduced sulfhydryls; sulfhydryl loss was threefold higher in lungs stored before perfusion compared with freshly perfused lungs. Reperfusion of stored, not fresh, lungs was associated with DNA damage. No loss of protein sulfhydryls occurred following lung perfusion. We conclude that DNA damage, loss of reduced nonprotein sulfhydryls, and lipid peroxidation during reperfusion of stored lungs may be responsible for physiologic lung dysfunction.

A critical role for thiol, but not ATP, depletion in 95% O2-mediated injury of preterm pneumocytes in vitro

Prolonged exposure to elevated partial pressures of oxygen results in lung cell toxicity, both in vivo and in vitro, due to the excess production and target molecule reactions of reactive oxygen species. Events primarily responsible for cell death vary with the type of oxidant injury and with cell type. Because of the susceptibility of the premature lung to oxygen toxicity, and the critical barrier function of the epithelium, we have investigated the role of two potentially lethal consequences of O2 exposure in premature distal lung epithelial cells in vitro. A 48-h exposure of distal fetal rat lung epithelial cells to 95% O2 caused cytotoxicity, which was associated with DNA injury and depletion of both cellular protein and nonprotein reduced sulfhydryls. The observed DNA injury preceded other markers of cell injury and was not sufficient to either activate the chromosomal enzyme poly(ADP-ribose) polymerase or cause secondary ATP depletion. Buthionine sulfoxamine-induced depletion of nonprotein reduced sulfhydryls increased the sensitivity of cells to subsequent O2-mediated cytotoxicity. Addition of the glutathione precursor N-acetylcysteine to the culture medium maintained cellular protein and nonprotein reduced sulfhydryl concentrations and prevented O2-mediated cytotoxicity. We conclude that loss of protein and nonprotein reduced sulfhydryls, but not DNA injury, is causally related to the toxic effects of elevated O2 on premature distal lung epithelial cells.

Antibiotic efficacy in intraabdominal sepsis: a clinically relevant model

We present preliminary data on the role of antibiotics in intraabdominal sepsis using a new, clinically relevant animal model. Peritoneal cavity infection was induced by ligation and perforation of the cecum in adult rats. Surviving rats were randomized to receive either saline or cefoxitin at the time of cecal excision and peritoneal lavage, 18 h after the onset of infection. This is different from previous models of abdominal sepsis (in which antibiotics are given within 4 h of peritoneal contamination) and mimics the clinical setting in which antibiotics are initiated much later, at the time of operation. Antibiotic-treated rats received 20 mg cefoxitin i.m. every 8 h for 7 days; controls received saline at similar times. Thirty-nine of 67 control rats died (58%) versus 20 of 64 (31%) that received cefoxitin (p less than 0.005). We conclude that even with delayed administration, antibiotics appear to improve the outcome of intraabdominal sepsis. With further characterization of this model we plan to use it as an in vivo assay to compare the efficacy of different antimicrobial agents in intraabdominal sepsis.