How sick are dialysis patients undergoing cholecystectomy? Analysis of 92,672 patients from the American College of Surgeons National Surgical Quality Improvement Program database.

BACKGROUND: Although cholecystectomy is one of the most common surgical procedures performed in the United States, there is an absence of data on the risks of cholecystectomy in dialysis patients. Our objective was to analyze the outcomes of cholecystectomy in dialysis patients. METHODS: Using the American College of Surgeons National Surgical Quality Improvement Program database, we selected all patients who underwent cholecystectomy from 2005 to 2010. Univariate analysis was performed and logistic and linear regression models were used to obtain risk-adjusted outcomes. The main outcomes were morbidity, mortality, and length of stay. RESULTS: Dialysis was associated with a higher risk of 30-day postoperative morbidity (16.1% vs 3.8%, adjusted odds ratio 1.91, 95% confidence interval 1.18 to 3.10), but not mortality. The average length of stay following any cholecystectomy was 4.1 days longer for dialysis patients (5.5 vs 1.4 days, P < .0001). CONCLUSION: Patients on dialysis who undergo cholecystectomy are at a higher risk for postoperative morbidity, but not mortality.

Irreversible electroporation facilitates gene transfer of a GM-CSF plasmid with a local and systemic response.

BACKGROUND: Electroporation uses an electric field to induce pores in the cell membrane that can transfer macromolecules into target cells. Modulation of electrical parameters leads to irreversible electroporation (IRE), which is being developed for tissue ablation. We sought to evaluate whether the application of IRE may induce a lesser electric field in the periphery where reversible electroporation may occur, facilitating gene transfer of a granulocyte macrophage colony-stimulating factor (GM-CSF) plasmid to produce its biologic response. METHODS: Yorkshire pigs underwent laparotomy, and IRE of the liver was performed during hepatic arterial infusion of 1 or 7 mg of a naked human GM-CSF plasmid. The serum, liver, lymph nodes, and bone marrow were harvested for analysis. RESULTS: Human GM-CSF level rose from undetectable to 131 pg/mL in the serum at 24 hours after IRE and plasmid infusion. The liver demonstrated an ablation zone surrounded by an immune infiltrate that had greater macrophage intensity than when treated with IRE or plasmid infusion alone. This dominance of macrophages was dose dependent. Distant effects of GM-CSF were found in the bone marrow, where proliferating myeloid cells increased from 14% to 25%. CONCLUSION: IRE facilitated gene transfer of the GM-CSF plasmid and brought about a local and systemic biologic response. This technique holds potential for tumor eradication and immunotherapy of residual cancer.

Gold nanoparticles provide bright long-lasting vascular contrast for CT imaging.

OBJECTIVE: Iodinated contrast agent for CT has a short half-life in the vasculature. As the field of interventional procedures expands, a more durable contrast agent would be highly useful. Our study investigated whether gold nanoparticles are feasible as a long-lasting vascular contrast agent for CT. MATERIALS AND METHODS: Gold nanoparticles were synthesized by a modified Turkevich method, coated with methoxy-polyethylene glycol-thiol chains, and compared with an iodine-based contrast agent used in mice. Contrast agents were imaged in tubes by CT at 40, 60, and 140 kVp and then were tested in vivo by tail vein injection. Nine mice received gold nanoparticles, two received iodine-based contrast agent, and one received saline. CT of mice was performed at 60 kVp immediately, 6 hours, and 24 hours after injection. RESULTS: In an isolated form in tubes, gold nanoparticles had greater radiographic density than did iodine-based contrast agent at 40 kVp and were comparable at the other CT voltages. In mice, gold nanoparticles provided bright contrast enhancement that enabled clear visualization of the abdominal aorta and renal arteries, which could not be distinguished without contrast agent. This persisted up to 24 hours, which was the last time point assessed. Contrast enhancement of the vasculature by iodine-based contrast agent was present immediately after injection but had disappeared by 6 hours. CONCLUSION: Gold nanoparticles can provide clear and durable contrast enhancement of the vasculature even at 24 hours. These findings merit further study of gold nanoparticles for their potential as a contrast agent in CT and CT-guided interventional procedures.

Irreversible electroporation ablation of the liver can be detected with ultrasound B-mode and elastography.

BACKGROUND: Irreversible electroporation (IRE) is a novel ablation technique that induces permanent membrane permeability and cell death. We are interested in ultrasound B-mode and elastography to monitor IRE ablation in the liver. METHODS: Yorkshire pigs underwent IRE ablation of the liver and were imaged with ultrasound B-mode and elastography. Histologic evaluation of cell death by triphenyltetrazolium chloride and hematoxylin and eosin staining was performed. RESULTS: Elastography showed that liver ablated by IRE exhibited increased tissue stiffness with a peak strain ratio of 2.22. The IRE lesion had a discrete border without bubble artifact, and the lesion size significantly correlated with area of cell death on histology. IRE ablation was unaffected by presence of large blood vessels or bile ducts. CONCLUSION: IRE ablation led to increased tissue stiffness that was detectable by elastography and indicative of cell death. Elastography may complement B-mode ultrasonography to monitor IRE ablation of the liver.

Spray cryotherapy is effective for bronchoscopic, endoscopic and open ablation of thoracic tissues.

OBJECTIVES: Spray cryotherapy (SCT) delivers a liquid nitrogen spray via a catheter to produce cellular death. This study seeks to determine the histological changes after bronchoscopic, endoscopic and open SCT on tissues in the thoracic cavity. METHODS: Yorkshire pigs underwent flexible bronchoscopy, endoscopy and thoracotomy for SCT of the airway, oesophagus and other intrathoracic structures, respectively. Variations in the duration and number of spray cycles for the same dosimetry were compared. RESULTS: Bronchoscopic SCT of the airway resulted in cellular death up to the cartilage layer. Endoscopic SCT of the oesophagus led to cell death up to the adventitial layer. Tissue necrosis was severe in the lung, of full thickness in the pleura, but very superficial in the great vessels. The extracellular matrix (ECM) of treated tissues remained well-preserved. Having shorter but more cycles of SCT decreased the depth of the cellular necrosis. One pig developed ventricular fibrillation during the surgery and expired. CONCLUSIONS: SCT causes reproducible tissue injury with the preserved ECM of most tissues within the thoracic cavity, making it enticing for ablation around vital structures like the great vessels with a decreased long-term risk. Further study is warranted to investigate the adverse events during SCT.

Bioluminescence imaging serves as a dynamic marker for guiding and assessing thermal treatment of cancer in a preclinical model.

BACKGROUND: Bioluminescence has been harnessed as a dynamic imaging technique in research. This is a proof of principle study examining feasibility of using bioluminescent proteins as a marker to guide therapeutic ablation. METHODS: Mesothelioma cancer cells (MSTO-Td) were transfected with a retroviral vector bearing firefly luciferase gene, plated in serial dilutions, and imaged to compare bioluminescence signal to cell number, determining threshold of bioluminescence detection. MSTO-Td cells were subjected to thermal treatment in a heated chamber; the bioluminescence signal and number of remaining live cancer cells were determined. Mice with MSTO-Td xenografts underwent electrocautery tumor ablation guided by bioluminescence imaging; bioluminescence signal and tumor size were monitored for 3 weeks. RESULTS: MSTO-Td cells emitted a bright, clear, bioluminescence signal that amplified with the cell number (P < .001) and was detectable with as few as 10 cells in cell culture. Bioluminescence decreased in a dose-dependent fashion upon thermal treatment as temperature increased from 37 to 70 °C (P < .001) and as treatment duration increased from 5 to 20 min (P < .001). This correlated with the number of remaining live MSTO-Td cells (Pearson coefficient = 0.865; P < .001). In mice, the bioluminescence signal correlated with tumor size posttreatment and effectively guided the ablation procedure to completion, achieving 0 % tumor recurrence. CONCLUSIONS: Bioluminescence imaging is a sensitive, real-time imaging approach; bioluminescence reporters such as firefly luciferase can assess and guide thermal treatment of cancer. This encourages research into bioluminescence imaging as a molecular technique with potential to target tumors via biomarkers and optimize thermal treatment procedures in a clinical setting.

Flexible CO2 laser and submucosal gel injection for safe endoluminal resection in the intestines.

BACKGROUND: The CO(2) laser's unique wavelength of 10.6 µm has the advantage of being readily absorbed by water but historically limited it to line-of-sight procedures. Through recent technological advances, a flexible CO(2) laser fiber has been developed and holds promise for endoluminal surgery. We examined whether this laser, along with injection of a water-based gel in the submucosal space, will allow safe dissection of the intestines and enhance the potential of this tool for minimally invasive surgery. METHODS: Using an ex vivo model with porcine intestines, spot ablation was performed with the flexible CO(2) laser at different power settings until transmural perforation. Additionally, excisions of mucosal patches were performed by submucosal dissection with and without submucosal injection of a water-based gel. RESULTS: With spot ablation at 5 W, none of the specimens was perforated by 5 min, which was the maximum recorded time. The time to perforation was significantly shorter with increased laser power, and gel pretreatment protected the intestines against spot ablation, increasing the time to perforation from 6 to 37 s at 10 W and from 1 to 7 s at 15 W. During excision of mucosal patches, 56 and 83% of untreated intestines perforated at 5 and 10 W, respectively. Gel pretreatment prior to excision protected all intestines against perforation. These specimens were verified to be intact by inflation with air to over 100 mmHg. Furthermore, excision of the mucosal patch was complete in gel-pretreated specimens, whereas 22% of untreated specimens had residual islands of mucosa after excision. CONCLUSION: The flexible CO(2) laser holds promise as a precise dissection and cutting tool for endoluminal surgery of the intestines. Pretreatment with a submucosal injection of a water-based gel protects the intestines from perforation during ablation and mucosal dissection.

Irreversible electroporation is a surgical ablation technique that enhances gene transfer.

BACKGROUND: Reversible electroporation has long been used to transfer macromolecules into target cells in the laboratory by using an electric field to induce transient membrane permeability. Recently, the electric field has been modulated to produce permanent membrane permeability and cell death. This novel technique, irreversible electroporation (IRE), is being developed for nonthermal cancer ablation. We hypothesize that outside the central zone of IRE exists a peripheral zone of reversible electroporation where gene transfer may occur. METHODS: IRE of the liver was performed in a Yorkshire pig model with administration of a plasmid expressing the marker gene green fluorescent protein (GFP) by bolus or primed infusion through the hepatic artery or portal vein. After 6 hours, livers were harvested for fluorescent microscopy and histologic examination. RESULTS: Of 36 liver specimens treated with IRE and the GFP plasmid, 31 demonstrated strong green fluorescence. Liver ablation by IRE was demarcated clearly on histology. CONCLUSION: IRE is a promising technique not only for operative tissue ablation but also for gene therapy. Because IRE ablation may leave behind intact tumor antigens, these findings encourage clinical studies of tumor ablation with delivery of immunostimulatory plasmids for combined local eradication and systemic immunotherapy.

Compartment syndrome after endoscopic harvest of the great saphenous vein during coronary artery bypass grafting.

Compartment syndrome is a limb-threatening condition often associated with traumatic, crush, burn, and reperfusion injuries. It is characterized by the development of disproportionately severe pain, paresthesias, decreased range of motion, loss of pulse, and a tense, edematous limb. In addition, measured compartment pressures and creatine phosphokinase values are often elevated. The definitive treatment is a decompressive fasciotomy. Compartment syndrome after coronary artery bypass grafting, however, is rare. The few reported cases all occurred in the vein donor leg after open harvest. We present a patient with compartment syndrome after endoscopic harvest of the saphenous vein for coronary artery bypass grafting.

Carcinosarcoma of the oesophagus - a rare mixed type of tumor.

Oesophageal carcinosarcoma is a rare type of oesophageal cancer composed of both squamous cells and sarcomatous cells. We report a case of a 71 year old man presenting with dysphagia and weight loss. Oesophagogastroduodenoscopy revealed a bulky mass with a preliminary diagnosis of only oesophageal carcinoma, and the oesophageal mass was resected with a transhiatal oesophagectomy. On surgical pathology, it was discovered that the tumor had both squamous cell and sarcomatous cell components, and the final diagnosis was changed to oesophageal carcinosarcoma. We discuss the presentation, differential diagnosis, treatment, and prognosis of this unique entity.

Access to adequate nutrition is a major potential obstacle to antiretroviral adherence among HIV-infected individuals in Rwanda.

Despite the massive expansion of antiretroviral drugs in Africa, little is known about the resulting changes in sexual behavior or obstacles to antiretroviral therapy (ART) adherence. Our evaluation of Rwandan adults on ART found no increase in risky sexual behaviors, but an obstacle to ART initiation and adherence for 76% of patients was a fear of developing too much appetite without enough to eat. Access to adequate nutrition may be a major determinant for long-term adherence to ART.