John D. Allendorf

Better preservation of immune function after laparoscopic-assisted vs . open bowel resection in a murine model

PURPOSE: We evaluated cell-mediated immune function after laparoscopic-assisted and open bowel resection in rats by measuring delayed-type hypersensitivity responses to keyhole limpet hemocyanin (KLH) and phytohemagglutinin (PHA). METHODS: Male Sprague-Dawley rats (n=120) were sensitized to 1 mg of KLH ten days before investigations. Rats were challenged preoperatively, immediately postoperatively, and on postoperative day (POD) 2 with an intradermal injection of 0.3 mg of KLH and 0.2 mg of PHA (at different sites). Averages of two measures of perpendicular diameters (taken 24 and 48 hours postchallenge) were used to calculate the area of induration using the formula for the area of an ellipse, A=(D1/2×D2/2)×π. Anesthesia control animals underwent no procedure (n=40). Open resection group underwent ligation and resection of the cecum (length=2 cm) through a 7 cm midline incision (n=40). In the laparoscopic-assisted resection group, under CO2 pneumoperitoneum (4–6 mmHg), the cecum was identified, dissected free, and exteriorized through a 4 mm port. The cecum was then ligated and resected extracorporeally (n=40). RESULTS: Preoperative responses to both KLH and PHA were the same in all three groups. Furthermore, within each group, postoperative responses were similar. When groups were compared, the anesthesia group responses were significantly greater than the open resection group responses at all time points (P<0.05 for all comparisons). Laparoscopic-assisted resection group responses differed from control at only two of eight postoperative measures. Laparoscopic resection group responses were significantly greater than open resection group responses to challenge with both KLH and PHA on POD1 (P<0.02, for both comparisons) and POD 4 (P<0.05, for both comparisons). CONCLUSIONS: Postoperative cell-mediated immune function is better preserved after laparoscopic-assisted bowel resection than after open resection as assessed by skin antigen testing.

Trocar site recurrence is unlikely to result from aerosolization of tumor cells.

PURPOSE: This study was undertaken to investigate the ability of a high-pressure CO2 environment to aerosolize tumor cells in bothin vitroandin vivo models. (An aerosol is defined as a stable gaseous suspension of insoluble particles.) Also, this study was designed to determine if rapid desufflation is capable of transporting fluid laden with tumor cells. METHODS: The fourin vitro aerosol experiments were performed in an 18.9-l plastic vessel fitted with two 7-mm ports and a compliant latex balloon affixed to the top. After CO2 insufflation, the vessel was desufflated through a sterile soluset containing 25 ml of culture media that was subsequently emptied into a culture dish, incubated for two weeks, and periodicallyassessed for growth. At the bottom of the vessel, one of the following was placed: Study 1 and 2, a suspension of B16 melanoma or colon 26 tumor cells in liquid culture media; Study 3, colon 26 cells in saline solution; Study 4, several pieces of solid colon 26 tumor. In Studies 1 to 3, cell preparations were subjected to the following high-pressure CO2 conditions (pneumo): 1) static pneumo of 15 and 30 mmHg (10 minute dwell); 2) a continuous flow (CF) of CO2 (10 l) while maintaining a pressure of 15 or 30 mmHg in the vessel. In Study 4, only the 30 mmHg static and CF conditions were tested. Between 6 and 12 determinations were performed for each condition and cell preparation.In vivo aerosol experiments consisted of Spraque Dawley rats that received intraperitoneal injections of 10-5 B16 cells in 0.1 ml of liquid media.Two laparoscopic ports were placed in the abdomen, one each for insufflation and desufflation. Study groups were: 1, static CO2 pneumo of 15 mmHg; 2 and 3, continuous CO2 flow (10 l) at a stable pneumo pressure of 5 and 10 mmHg. Desufflation was performedvia the same collecting device and handled in an identical manner to thein vitroexperiments described above. Thein vitro balloon experiment was designed to investigate the ability of desufflation to transport fluid-containing tumor cells; latex balloon model was used. To prevent complete loss of volume on desufflation, a wire coil was placed inside the balloon. Twenty ml of media containing 20×10−6B16 cells was placed in the bottom of the balloon. The balloon was insufflated with 1 to 21 of gas. There were three study groups that differed in the degree to which the cell suspension was agitated before desufflation. Study conditions were as follows: 1) no agitation; 2) moderate agitation to coat the lower walls and coil; 3) maximum agitation to coat the entire balloon. To verify the viability of tumor cells,at the end of eachin vitroandin vivo study, a sample of tumor cells or peritoneal washing was incubated in sterile media. These samples served as positive controls. RESULTS:In vitro aerosol studies consisted of the following. At the end of two weeks of incubation, no tumor growth was noted in any of the 124 test dishes. The 14 control samples all demonstrated tumor growth.In vivo aerosol studies consisted of the following. Zero of 18 experimental dishes grew tumor. All three peritoneal washing samples demonstrated growth.In vitro balloon studies consisted of the following. Zero of 12 test dishes in Groups 1 and 2 demonstrated growth, whereas five of six dishes did so in Group 3 (maximally agitated before desufflation). Again, positive controls all grew tumor cells. SUMMARY: We were unable to demonstrate aerosol formation in any of thein vitroandin vivo studies performed. In the balloon experiment, desufflation-related transport of tumor cells was demonstrated but only when the entire balloon surface was coated with the tumor cell suspension before desufflation. CONCLUSION: Aerosols of tumor cells are not likely to form. Free intraperitoneal tumor cells are most likely found in liquid suspension. Desufflation is a potential means of transport of cell-laden fluid.

PIK3CA Mutations in Intraductal Papillary Mucinous Neoplasm/Carcinoma of the Pancreas

Purpose: Recent studies have reported high frequencies of somatic mutations in the phosphoinositide-3-kinase catalytic-α (PIK3CA) gene in various human solid tumors. More than 75% of those somatic mutations are clustered in the helical (exon 9) and kinase domains (exon 20). The three hot-spot mutations, E542K, E545K, and H1047R, have been proven to elevate the lipid kinase activity of PIK3CA and activate the Akt signaling pathway. The mutational status of PIK3CA in intraductal papillary mucinous neoplasm/carcinoma (IPMN/IPMC) has not been evaluated previously. Experimental Design: To evaluate a possible role for PIK3CA in the tumorigenesis of IPMN and IPMC, exons 1, 4, 5, 6, 7, 9, 12, 18, and 20 were analyzed in 36 IPMN/IPMC and two mucinous cystadenoma specimens by direct genomic DNA sequencing. Results: We identified four missense mutations in the nine screened exons of PIK3CA from 36 IPMN/IPMC specimens (11%). One of the four mutations, H1047R, has been previously reported as a hot-spot mutation. The remaining three mutations, T324I, W551G, and S1015F, were novel and somatic. Conclusion: This is the first report of PIK3CA mutation in pancreatic cancer. Our data provide evidence that the oncogenic properties of PIK3CA contribute to the tumorigenesis of IPMN/IPMC.

Increased tumor establishment and growth after open vs laparoscopic surgery in mice may be related to differences in postoperative T-cell function

AbstractBackground: Previous work has demonstrated that cell-mediated immune function in rats is better preserved after laparoscopic than open surgery. We have also shown that tumors are more easily established in mice and grow larger after sham laparotomy than after pneumoperitoneum. The purpose of this study is to determine if the functional status of the cell-mediated immune system influences postoperative tumor growth. Methods: Immunocompetent (study 1) and T-cell deficient athymic (study 2) mice were injected with mouse mammary carcinoma cells in the dorsal skin. Mice then underwent either no procedure, midline laparotomy, or carbon dioxide pneumoperitoneum. Tumor masses on postoperative day 12 were compared. Results: In immunocompetent mice, laparotomy group tumors were nearly twice as large as laparoscopy group tumors (p < 0.02), which were 1.5 times as large as control group tumors (NS). In the athymic model, however, differences between the sham laparotomy and pneumoperitoneum groups were lost (p > 0.5). Tumors grew much larger in the athymic control mice than in the immunocompetent control mice (p < 0.01). Conclusion: We conclude that T-cell function plays a significant role in host containment of mouse mammary carcinoma and in the mechanism of differences in tumor growth observed after laparotomy and pneumoperitoneum.

Thyroidectomy using monitored local or conventional general anesthesia: an analysis of outpatient surgery, outcome and cost in 1,194 consecutive cases.

BackgroundCritical appraisal of safety, feasibility, and economic impact of thyroidectomy procedures using local (LA) or general anesthesia (GA) is performed.MethodsConsecutive patients undergoing thyroidectomy procedures were selected from a prospective database from January 1996 to June 2003 of a single-surgeon practice at a tertiary center. Statistical analyses determined differences in patient characteristics, outcomes, operative data, and length of stay (LOS) between groups. A cohort of consecutive patients treated in 2002–2003 by all endocrine surgeons at the institution was selected for cost analysis.ResultsA total of 1,194 patients underwent thyroidectomy, the majority using LA (n = 939) and outpatient surgery (65%). Female gender (76%), body mass index ≥30 kg/m2 (29%), median age (49 years), and cancer diagnosis (45%) were similar between groups. Extent of thyroidectomy (59% total) and concomitant parathyroidectomy (13%) were similarly performed. GA was more commonly utilized for patients with comorbidity [15% vs. 10%, Anesthesia Society of America (ASA) ≥3; P < 0.001], symptomatic goiter (13% vs. 7%; P = 0.004), reoperative cases (10% vs. 6%; P = 0.01), and concomitant lymphadenectomy procedures (15% vs. 3%; P < 0.001). GA was associated with significant increase in LOS ≥24 hours (17 % vs. 4%) or overnight observation (49 % vs. 14%), P < 0.001. Operative room utilization was significantly associated with type of anesthesia (180 min vs. 120 min, GA vs. LA, P < .001) and impacted to a lesser degree by surgeon operative time (89 minutes vs. 76 minutes, GA vs. LA; P = .089). Overall morbidity rates were similar between groups (GA 5.8 % vs. LA 3.2%). The actual total cost (ATC) per case for GA was 48% higher than for LA and 30% higher than the ATC for all procedures (P = 0.006), with the combined weighted average impacted by more LA cases (n = 217 vs. 85).ConclusionThese data from a large, unselected group of thyroidectomy patients suggest LA results in similar outcomes and morbidity rates to GA. It is likely that associated LA costs are lower.

Increased tumor establishment and growth after open vs laparoscopic bowel resection in mice

AbstractBackground: Surgery can suppress immune function and facilitate tumor growth. Several studies have demonstrated better preservation of immune function following laparoscopic procedures. Our laboratory has also shown that tumors are more easily established and grow larger after sham laparotomy than after pneumoperitoneum in mice. The purpose of this study was to determine if the previously reported differences in tumor establishment and growth would persist in the setting of an intraabdominal manipulation. Methods: Syngeneic mice received intradermal injections of tumor cells and underwent either an open or laparoscopic cecal resection. In study 1, the incidence of tumor development was observed after a low dose inoculum; whereas in study 2, tumor mass was compared on postoperative day 12 after a high-dose inoculum. Results: In study 1, tumors were established in 5% of control mice, 30% of laparoscopy mice, and 83% of open surgery mice (p < 0.01 for all comparisons). In study 2, open surgery group tumors were 1.5 times as large as laparoscopy group tumors (p < 0.01), which were 1.5 times as large as control group tumors (p < 0.02). Conclusion: We conclude that tumors are more easily established and grow larger after open laparoscopic bowel resection in mice.

Better preservation of endocrine function after central versus distal pancreatectomy for mid-gland lesions.

BACKGROUND Traditional resections for benign and low-grade malignant neoplasms of the mid pancreas result in loss of normal parenchyma that can cause pancreatic endocrine and exocrine insufficiency. Central pancreatectomy (CP) is a parenchyma-sparing option for such lesions. This study evaluates a single institutions experience with CP and compares outcomes with distal pancreatectomy (DP). METHODS We retrospectively collected data on CP patients from 1997 through 2009 and evaluated outcomes. In a subset of 50 patients, we performed a matched-pairs analysis to directly compare the short- and long-term outcomes of CP and DP. RESULTS Seventy-three patients underwent CP with a median operating room time of 254 minutes. Overall morbidity was 41.1% with pancreatic fistula in 20.5%. Mortality was 0%. There were no differences in fistula, morbidity, and mortality rates between the CP and DP groups. The CP group had resected for smaller lesions. CP patients had a lower rate of new-onset and worsening diabetes than DP patients (14% vs 46%; P = .003). Of new-onset and worsening diabetics, only 1 CP patient required insulin compared with 14 DP patients (P = .002). CONCLUSION CP is safe and effective for select neoplasms of the mid pancreas. Patients undergoing CP have markedly decreased insulin requirements compared with DP patients.

Soluble Ig-Like Transcript 3 Inhibits Tumor Allograft Rejection in Humanized SCID Mice and T Cell Responses in Cancer Patients

Attempts to enhance patients’ immune responses to malignancies have been largely unsuccessful. We now describe an immune-escape mechanism mediated by the inhibitory receptor Ig-like transcript 3 (ILT3) that may be responsible for such failures. Using a humanized SCID mouse model, we demonstrate that soluble and membrane ILT3 induce CD8+ T suppressor cells and prevent rejection of allogeneic tumor transplants. Furthermore, we found that patients with melanoma, and carcinomas of the colon, rectum, and pancreas produce the soluble ILT3 protein, which induces the differentiation of CD8+ T suppressor cells and impairs T cell responses in MLC. These responses are restored by anti-ILT3 mAb or by depletion of soluble ILT3 from the serum. Immunohistochemical staining of biopsies from the tumors and metastatic lymph nodes suggests that CD68+ tumor-associated macrophages represent the major source of soluble ILT3. Alternative splicing, resulting in the loss of the ILT3 transmembrane domain, may contribute to the release of ILT3 in the circulation. These data suggest that ILT3 depletion or blockade is crucial to the success of immunotherapy in cancer. In contrast, the inhibitory activity of soluble ILT3 on T cell alloreactivity in vitro and in vivo suggests the potential usefulness of rILT3 for immunosuppressive treatment of allograft recipients or patients with autoimmune diseases.

One Hundred Thirty Resections for Pancreatic Neuroendocrine Tumor: Evaluating the Impact of Minimally Invasive and Parenchyma-Sparing Techniques

BackgroundIncreasingly, surgeons apply minimally invasive and parenchyma-sparing techniques to the management of pancreatic neuroendocrine tumor (PNET). The aim of this study was to evaluate the impact of these approaches on patient outcomes.MethodsWe retrospectively collected data on patients with PNET and compared perioperative and pathologic variables. Survival was analyzed using the Kaplan–Meier method. Factors influencing survival were evaluated using a Cox proportional hazards model.ResultsOne hundred thirty patients underwent resection for PNET. Traditional resections included 43 pancreaticoduodenectomies (PD), 38 open distal pancreatectomies (DP), and four total pancreatectomies. Minimally invasive and parenchyma-sparing resections included 25 laparoscopic DP, 11 central pancreatectomies, five enucleations, three partial pancreatectomies, and one laparoscopic-assisted PD. Compared to traditional resections, the minimally invasive and parenchyma-sparing resections had shorter hospital stays. By univariate analysis of neuroendocrine carcinoma, liver metastases and positive resection margins correlated with poor survival. There was an increase in minimally invasive or parenchyma-sparing resections over the study period with no differences in morbidity, mortality, or survival.ConclusionIn this series, there has been a significant increase in minimally invasive and parenchyma-sparing techniques for PNET. This shift did not increase morbidity or compromise survival. In addition, minimally invasive and parenchyma-sparing operations yielded shorter hospital stays.

Transluminal aortic valve placement. A feasibility study with a newly designed collapsible aortic valve.

Percutaneous stents are used in vascular applications in conjunction with angioplasty and in combination with graft material for repair of abdominal aneurysms. The authors have designed a collapsible bioprosthetic aortic valve for placement by a transluminal catheter technique. This trileaflet stent valve is composed of stainless steel and bovine pericardium. Stent valves, 23 and 29 mm, were tested in a pulse duplicator system with rigid rings from 21 to 31 mm in 2 mm increments. At a mean flow of 3.1 L/min (+/-0.7), normal systemic aortic pressure was generated with a transvalvular gradient of 14.9 +/- 7 mmHg (mean +/- SD). Regurgitation fraction ranged from 10 to 18% (mean 13.8 +/- 3%) in the best ring size. Valves with the best hemodynamic profile were used for implantation in three 70 kg pigs in an open chest model. The valve was collapsed in a 24 Fr catheter designed to allow slow, controlled release. After resection of the native leaflets, the new valve was placed in the subcoronary position. No additional sutures were used for securing the valve. Two animals were successfully weaned from cardiopulmonary bypass and maintained systemic pressures of 100/45 (+/-10) and 116/70 (+/-15) mmHg, respectively. Intraoperative color echocardiography revealed minimal regurgitation, central flow, full apposition of all leaflets, and no interference with coronary blood flow. Both animals were sacrificed after being off bypass for 2 hr. Postmortem examination revealed the valves to be securely anchored. The third animal was weaned from cardiopulmonary bypass but developed refractory ventricular fibrillation because of valve dislodgment due to structural failure. Although long term survival data are needed, development of a hemodynamically acceptable prosthetic aortic valve for transluminal placement is feasible.