A murine xenograft model of spontaneous metastases of human lung adenocarcinoma

BACKGROUND

The flank is commonly used for primary xenografts in mice, but it is rare for these tumors to metastasize. Tail vein injection creates a pattern of metastases, but is artificial. We hypothesized that the liver is a convenient alternative xenograft site and that metastases would gradually proceed spontaneously.

MATERIALS AND METHODS

Using 15 NOD.CB17-Prkdc(scid)/NcrCrl (NOD/SCID) mice, 10,000 A549 cells were xenografted into the liver while a second group of five mice were xenografted in the flank with 100,000 A549 cells as a control. Mice were euthanized and grossly dissected at 7 wk. A third group of seven mice received liver xenografts with A549 and a mouse each week was euthanized for 7 wk and evaluated. The liver, lung, and spleen were examined histologically.

RESULTS

At 7 wk, 15/15 liver xenografted mice had gross primary tumor in the liver. Histologic review confirmed multiple microscopic foci of metastatic disease in all mice (15/15) throughout the lungs, mediastinal nodes, and spleen. The control group had primary tumor in the flank (4/5), but none had histologic evidence of metastases. Serially euthanized liver xenografted mice revealed evidence of a gradual spontaneous metastatic model system with the first histologic findings of micrometastases appearing in the lungs by wk 5, which became wide spread by wk 7. Splenic and mediastinal lymph node metastases developed in wk 6 and 7.

CONCLUSIONS

Liver xenografting of A549 cells into NOD/SCID mice is a reliable way of developing widespread micrometastases. This model allows the study of a gradually developing solid tumor with subsequent metastatic spread.

Epidural ropivacaine and sufentanil and the perioperative stress response after a radical retropubic prostatectomy

BACKGROUND

The effects of an epidural opioid and a local anesthetic on the perioperative stress responses have not been fully investigated in elderly patients undergoing cancer surgery. We hypothesized that the stress response after a radical retropubic prostatectomy (RRP) would be attenuated by epidural ropivacaine and sufentanil.

METHODS

In this randomized, double-blinded study, we included patients above 65 years of age who were scheduled for a RRP. In addition to general anesthesia, they received either epidural saline continuously (5 ml/h) (C group, n=20); 0.3% ropivacaine (R group, n=20); or 0.3% ropivacaine combined with 1 μg/ml sufentanil (RS group; n=20). We determined the concentrations of glucose, insulin, cortisol, epinephrine, norepinephrine, and prolactin before, during, and up to 48 h after surgery.

RESULTS

The concentrations of glucose and insulin increased in all the groups. The cortisol level increased in the C group while it decreased significantly in the RS group. Epinephrine and norepinephrine concentrations increased significantly after surgery in the C group, but not in the R and RS groups. The prolactin concentration increased in all the groups, and was higher in the RS group than in the other groups (P=0.002). Post-operative pain scores and analgesic requirement were lower in the R and RS groups.

CONCLUSION

Epidural ropivacaine blunted the perioperative stress responses in elderly patients undergoing a RRP. The combination of epidural ropivacaine and sufentanil was associated with the most pronounced attenuation of the stress response. ClinicalTrial.gov registration number: NCT01086956.

Quality of life comparison between open and retroperitoneal video-assisted minilaparotomy surgery for kidney donors

This study compared open and video-assisted minilaparotomy surgery in live kidney donors for quality of life (QoL), pain, cosmesis, and recovery. Between January 2003 and March 2006, we reviewed data from 205 patients who underwent live-donor nephrectomy: 116 by video-assisted minilaparotomy and 89 by open surgery. Pain and satisfaction were evaluated using scales from 1 to 10, and QoL, with the 36-item Short Form questionnaire. Hospital stay was significantly shorter among the video-assisted (5.1 +/- 1.6 days) than the open group (6.9 +/- 1.3 days; P < .01). Time to resumption of walking without difficulty and normal activity was significantly shorter among the video-assisted than the open group (P<.01). The video-assisted group showed better QoL scores in 6 of 8 QoL categories, including physical role (P < .01), bodily pain (P < .01), general health (P < .01), vitality (P < .01), emotional health (P < .01), and mental health (P < .01). Patients in the video-assisted group (score, 7.3 +/- 2.4) were more satisfied with the cosmetic outcome than those in the open group (score, 5.1 +/- 3.0; P < .01). In conclusion, donors who underwent nephrectomy via video-assisted minilaparotomy showed better outcomes regarding pain, convalescence, cosmesis, and QoL than those who underwent open surgery.

Long-term survival outcomes by smoking status in surgical and nonsurgical patients with non-small cell lung cancer: comparing never smokers and current smokers

BACKGROUND

Survival outcomes of never smokers with non-small cell lung cancer (NSCLC) who undergo surgery are poorly characterized. This investigation compared surgical outcomes of never and current smokers with NSCLC.

METHODS

This investigation was a single-institution retrospective study of never and current smokers with NSCLC from 1975 to 2004. From an analytic cohort of 4,546 patients with NSCLC, we identified 724 never smokers and 3,822 current smokers. Overall, 1,142 patients underwent surgery with curative intent. For survival analysis by smoking status, hazard ratios (HRs) were estimated using Cox proportional hazard modeling and then further adjusted by other covariates.

RESULTS

Never smokers were significantly more likely than current smokers to be women (P < .01), older (P < .01), and to have adenocarcinoma (P < .01) and bronchioloalveolar carcinoma (P < .01). No statistically significant differences existed in stage distribution at presentation for the analytic cohort (P = .35) or for the subgroup undergoing surgery (P = .24). The strongest risk factors of mortality among patients with NSCLC who underwent surgery were advanced stage (adjusted hazard ratio, 3.43; 95% CI, 2.32-5.07; P < .01) and elevated American Society of Anesthesiologists classification (adjusted hazard ratio, 2.18; 95% CI, 1.40-3.40; P < .01). The minor trend toward an elevated risk of death on univariate analysis for current vs never smokers in the surgically treated group (hazard ratio, 1.20; 95% CI, 0.98-1.46; P = .07) was completely eliminated when the model was adjusted for covariates (P = .97).

CONCLUSIONS

Our findings suggest that smoking status at time of lung cancer diagnosis has little impact on the long-term survival of patients with NSCLC, especially after curative surgery. Despite different etiologies between lung cancer in never and current smokers the prognosis is equally dismal.

Giant multi-polypoid liposarcoma of the esophagus: an atypical presentation

Liposarcomas of the esophagus are rare with only 19 cases reported in the English literature. We present a giant, well-differentiated liposarcoma of the esophagus with multiple pedunculated polypoid-like growths, which made it radiographically and pathologically noncharacteristic. We discuss the diagnostic dilemmas, clinical and pathologic findings, and surgical treatment.

Solid polymeric microparticles enhance the delivery of siRNA to macrophages in vivo

Therapeutics based on small interfering RNA (siRNA) have a great clinical potential; however, delivery problems have limited their clinical efficacy, and new siRNA delivery vehicles are greatly needed. In this report, we demonstrate that submicron particles (800-900 nm) composed of the polyketal PK3 and chloroquine, termed as the PKCNs, can deliver tumor necrosis factor-alpha (TNF-alpha) siRNA in vivo to Kupffer cells efficiently and inhibit gene expression in the liver at concentrations as low as 3.5 microg/kg. The high delivery efficiency of the PKCNs arises from the unique properties of PK3, which can protect siRNA from serum nucleases, stimulate cell uptake and trigger a colloid osmotic disruption of the phagosome and release encapsulated siRNA into the cell cytoplasm. We anticipate numerous applications of the PKCNs for siRNA delivery to macrophages, given their high delivery efficiency, and the central role of macrophages in causing diseases such as hepatitis, liver cirrhosis and chronic renal disease.

Recurrence after neoadjuvant chemoradiation and surgery for esophageal cancer: does the pattern of recurrence differ for patients with complete response and those with partial or no response?

OBJECTIVE

We hypothesized that most relapses in patients with esophageal cancer having neoadjuvant chemoradiation therapy would occur outside of the surgical and radiation fields.

METHODS

Recurrence patterns, time to recurrence, and median survival were examined in 267 patients who had esophagectomy after neoadjuvant chemoradiation therapy at Johns Hopkins over 19 years.

RESULTS

Of 267 patients, 82 (30.7%) showed complete response to neoadjuvant therapy, with 108 (40.4%) and 77 (28.8%) showing partial response or no response, respectively. Recurrence developed in 84 patients (patients with complete response 18/82, 21.4%; patients with partial response 39/108, 36.1%; patients with no response 27/77, 35.1%; P = .055, respectively). Most patients had recurrences at distant sites (65/84;77.4%) regardless of pathologic response, and subsequent survival was brief (median 8.37 months). Median disease-free survival was short (10 months) and did not differ based on recurrence site for patients with partial response or no response, but was longer for patients with complete response with distant recurrence, whose median disease-free survival was 27.3 months (P = .008). By multivariate analysis, no other factor except for pathologic response to neoadjuvant therapy was associated with disease recurrence or death. Patients with partial response or no response were 1.97 and 2.23 times more likely to have recurrence than patients with complete response (P = .024 and P = .012, respectively).

CONCLUSIONS

Most esophageal cancer recurrences after neoadjuvant therapy and surgery are distant, and survival time after recurrence is short regardless of pathologic response. Fewer patients achieving complete response had recurrences, and distant recurrences in these patients manifest later than in patients showing partial response and those showing no response. Only pathologic response is significantly associated with disease recurrence, suggesting that tumor biology and chemosensitivity are critical in long-term patient outcome.

The delivery of superoxide dismutase encapsulated in polyketal microparticles to rat myocardium and protection from myocardial ischemia-reperfusion injury

Oxidative stress is increased in the myocardium following infarction and plays a significant role in death of cardiac myocytes, leading to cardiac dysfunction. Levels of the endogenous antioxidant Cu/Zn-superoxide dismutase (SOD1) decrease following myocardial infarction. While SOD1 gene therapy studies show promise, trials with SOD1 protein have had little success due to poor pharmacokinetics and thus new delivery vehicles are needed. In this work, polyketal particles, a recently developed delivery vehicle, were used to make SOD1-encapsulated-microparticles (PKSOD). Our studies with cultured macrophages demonstrated that PKSOD treatment scavenges both intracellular and extracellular superoxide, suggesting efficient delivery of SOD1 protein to the inside of cells. In a rat model of ischemia/reperfusion (IR) injury, injection of PKSOD, and not free SOD1 or empty particles was able to scavenge IR-induced excess superoxide 3 days following infarction. In addition, only PKSOD treatment significantly reduced myocyte apoptosis. Further, PKSOD treatment was able to improve cardiac function as measured by acute changes in fractional shortening from baseline echocardiography, suggesting that sustained delivery of SOD1 is critical during the early phase of cardiac repair. These data demonstrate that delivery of SOD1 with polyketals is superior to free SOD1 protein therapy and may have potential clinical implications.

Inspiring medical students to pursue surgical careers: outcomes from our cardiothoracic surgery research program

BACKGROUND

The past several years have witnessed a dramatic decline in the number of general surgery residents pursuing cardiothoracic surgery residency training. We believe that attracting individuals to pursue surgical careers should begin during the formative years of medical education. We implemented a program to introduce first-year medical students to cardiothoracic surgery and laboratory research.

METHODS

In 2003, we began a program providing an introduction to cardiothoracic laboratory research and surgery for medical students. Students are competitively selected for our three-part 8-week summer program. First, students are paired with a cardiothoracic surgery attending for shadowing in clinic and the operating room. Second, students actively participate in large-animal operations in the laboratory. Finally, students complete a clinical research project under the direction of a laboratory resident and faculty mentor. These projects are the students' own. They are responsible for presenting their findings to the division of cardiac surgery at the end of the program.

RESULTS

Since 2003, 18 students have completed the program. Each one has completed a project, collectively resulting in 39 peer-reviewed manuscripts. One student has published 28 peer-reviewed manuscripts. Of 10 students eligible for residency, 8 have applied in general surgery or surgical subspecialty (3 general, 2 plastic, 2 cardiothoracic, and 1 neurosurgery).

CONCLUSIONS

Implementing a program to introduce medical students to clinical and laboratory surgery has been successful, as measured by academic productivity. Eighty percent of eligible students entered a surgical field. Programs like these serve to stimulate interest in our specialty.

Resistin-like molecule-beta in scleroderma-associated pulmonary hypertension

Scleroderma is a systemic, mixed connective tissue disease that can impact the lungs through pulmonary fibrosis, vascular remodeling, and the development of pulmonary hypertension and right heart failure. Currently, little is known about the molecular mechanisms that drive this condition, but we have recently identified a novel gene product that is up-regulated in a murine model of hypoxia-induced pulmonary hypertension. This molecule, known as hypoxia-induced mitogenic factor (HIMF), is a member of the newly described resistin gene family. We have demonstrated that HIMF has mitogenic, angiogenic, vasoconstrictive, inflammatory, and chemokine-like properties, all of which are associated with vascular remodeling in the lung. Here, we demonstrate that the human homolog of HIMF, resistin-like molecule (RELM)-beta, is expressed in the lung tissue of patients with scleroderma-associated pulmonary hypertension and is up-regulated compared with normal control subjects. Immunofluorescence colocalization revealed that RELM-beta is expressed in the endothelium and vascular smooth muscle of remodeled vessels, as well as in plexiform lesions, macrophages, T cells, and myofibroblast-like cells. We also show that addition of recombinant RELM-beta induces proliferation and activation of ERK1/2 in primary cultured human pulmonary endothelial and smooth muscle cells. These results suggest that RELM-beta may be involved in the development of scleroderma-associated pulmonary hypertension.

Case report: treatment of severe subcutaneous emphysema with a negative pressure wound therapy dressing

OBJECTIVE

This article describes a patient who developed severe subcutaneous emphysema and a persistent air leak after several attempts at needle thoracostomy for what was thought to be a tension pneumothorax. Subcutaneous emphysema was effectively treated with a topical negative pressure wound therapy dressing applied to a typical subfacial "blowhole" incision. This article aims to describe and contextualize the use of negative pressure wound therapy within the existing treatment options for subcutaneous emphysema.

METHODS

A case report of the clinical course and technique was drafted, and the relevant literature in PubMed was reviewed.

RESULTS

The level of subcutaneous emphysema decreased significantly within 48 hours of negative pressure wound therapy as confirmed with physical examination and computed tomography scans. Negative pressure wound therapy for subcutaneous emphysema has not been previously described in the literature.

CONCLUSIONS

Negative pressure wound therapy applied over subfascial incisions is a novel technique that effectively and rapidly controlled massive subcutaneous emphysema and persistent air leak. This technique may be efficacious in other cases of subcutaneous emphysema.

The stimulation of CD8+ T cells by dendritic cells pulsed with polyketal microparticles containing ion-paired protein antigen and poly(inosinic acid)-poly(cytidylic acid)

New adjuvants and delivery strategies are needed to optimize the ability of protein-based vaccines to elicit CD8(+) T cell responses. We have developed a model vaccine formulation containing ovalbumin (OVA) and the double-stranded RNA analog poly(inosinic acid)-poly(cytidylic acid) (poly(I:C)), a TLR3 agonist. OVA and poly(I:C) were each ion-paired to cetyltrimethylammonium bromide (CTAB) to produce hydrophobic complexes, which were co-encapsulated in pH-sensitive polyketal (PK3) microparticles (1-3 microm) using a single emulsion method. Loading levels ranged from 13.6 to 18.8 microg/mg OVA and 4.8 to 10.3 microg/mg poly(I:C). Murine splenic dendritic cells (DCs) pulsed with PK3-OVA-poly(I:C) microparticles, at antigen doses of 0.01 and 0.1 microg/mL, induced a higher percentage of IFNgamma-producing CD8(+) T cells than DCs treated with PK3-OVA particles or soluble OVA/poly(I:C). A higher antigen dose (1 microg/mL) was less effective, which can be attributed to CTAB toxicity. At the lowest antigen dose (0.01 microg/mL), PK3-OVA-poly(I:C) microparticles also enhanced TNF-alpha and IL-2 production in CD8(+) T cells. These data demonstrate the potential of polyketal microparticles in formulating effective CD8(+) T cell-inducing vaccines comprising protein antigens and dsRNA adjuvants.

Sustained release of a p38 inhibitor from non-inflammatory microspheres inhibits cardiac dysfunction

Cardiac dysfunction following acute myocardial infarction is a major cause of death in the world and there is a compelling need for new therapeutic strategies. In this report we demonstrate that a direct cardiac injection of drug-loaded microparticles, formulated from the polymer poly(cyclohexane-1,4-diylacetone dimethylene ketal) (PCADK), improves cardiac function following myocardial infarction. Drug-delivery vehicles have great potential to improve the treatment of cardiac dysfunction by sustaining high concentrations of therapeutics within the damaged myocardium. PCADK is unique among currently used polymers in drug delivery in that its hydrolysis generates neutral degradation products. We show here that PCADK causes minimal tissue inflammatory response, thus enabling PCADK for the treatment of inflammatory diseases, such as cardiac dysfunction. PCADK holds great promise for treating myocardial infarction and other inflammatory diseases given its neutral, biocompatible degradation products and its ability to deliver a wide range of therapeutics.

Starch gelatinization and physical quality of pea flakes in canine dinners as affected by soaking, steam treatment and infrared radiation

Cleaned, whole smooth green peas (Pisum sativum L.) were reconstituted by soaking in tap water of 40 degrees C (15, 20 or 25 min) and subsequently either toasted (100 degrees C during 1.5 min) and infrared (IR) radiated or just IR radiated. For IR radiation, a small-scale, propane-fired IR radiation plant was used with average residence times of 58 and 92 s respectively. After exiting the conveyor belt, peas were held for a pre-determined period (holding: 0, 15 or 30 min respectively) in a well-insulated container. Finally, all radiated peas were flaked (roll distance 0.75 mm) in a flaking mill located posterior to the IR plant and analysed for chemical and physical properties. Initial pea starch gelatinization degree (SGD) was 10.1% at a total starch content of 410.1 g/kg. Infrared processing during 92 s significantly improved the SGD (from 10.1% to 32.8%) of pea flakes compared to treatment during 58 s (SGD of 18.6%). The SGD was further improved with steam treatment of peas, prior to IR. For all determined parameters, no effect of holding time could be observed. Starch gelatinization degree can be improved by soaking, toasting and IR processing. The substantial improvement of SGD, however can be only obtained by a longer IR residence time as well as through toasting, prior to the IR processing. The improvements in SGD, however are paralleled by a lower durability of flakes (range 34.9% to 87.4%).

Polyketal copolymers: a new acid-sensitive delivery vehicle for treating acute inflammatory diseases

Acute inflammatory diseases are a major cause of death in the world, and effective treatments are greatly needed. Macrophages play a central role in causing acute inflammatory diseases, and there is currently great interest in developing drug delivery vehicles that can target therapeutics to macrophages. Microparticles formulated from aliphatic polyketals have great potential to enhance the treatment of acute inflammatory diseases, due to their ability to passively target therapeutics to macrophages, their acid sensitivity, and their biocompatible degradation products. However, existing aliphatic polyketals are unsuitable for treating acute inflammatory diseases because they require weeks to hydrolyze, and strategies for accelerating their hydrolysis kinetics are greatly needed. In this report, we demonstrate that the hydrolysis kinetics of aliphatic polyketals can be accelerated by increasing their hydrophilic/hydrophobic balance. Aliphatic polyketals of varying hydrophobicity were synthesized, via the acetal exchange reaction, and their hydrolysis kinetics were investigated at the pH values of 4.5 and 7.4. A polyketal termed PK3 was developed, which had the hydrolysis kinetics suitable for treating acute inflammatory diseases. PK3 has a hydrolysis half-life of 2 days at pH 4.5, but requires several weeks to hydrolyze at pH 7.4. Microparticles were formulated with PK3, which encapsulated the anti-inflammatory drug, imatinib. In vivo experiments demonstrated that PK3 microparticles were able to significantly improve the efficacy of imatinib in treating acute liver failure. We anticipate that aliphatic polyketals will have numerous applications for the treatment of acute inflammatory diseases, given their pH sensitivity, tunable hydrolysis kinetics, and biocompatible degradation products.