A true orthotopic gastric cancer murine model using electrocoagulation.

BACKGROUND: Orthotopic mouse models of human gastric cancer represent an important in vivo tool for testing chemotherapeutic agents and for studying intraluminal factors. Currently, orthotopic mouse models of gastric cancer require an operative procedure involving either injection or implantation of tumor cells in stomach layers. The resultant tumor does not grow from the stomach's mucosal surface, so it does not mimic the human disease process. STUDY DESIGN: A low-dose gastric mucosal coagulation was done transorally in the body of stomach using a specially designed polyethylene catheter in 16 female severe combined immunodeficient mice. This was followed by the instillation of SNU-16 human gastric cancer tumor cells (1 × 10(6) cells). Five mice each were euthanized at 1 and 2 months, and 6 mice were euthanized at 3 months. Three control mice underwent electrocoagulation alone and 3 mice underwent cell line instillation alone. RESULTS: Tumors were detected in 11 of 16 experimental mice, but not in the control mice. Tumors were noted in mice at 1 month. Over time, there was an increase in tumor growth and metastasis to lymph nodes and surrounding organs. Histopathologic evaluation showed that the tumors grew from the gastric mucosa. CONCLUSIONS: Our model is easy to create and overcomes the limitations of the existing models, as the tumor arises from the stomach's mucosal layer and mimics the human disease in terms of morphology and biologic behavior. This is the first report of a true orthotopic gastric cancer murine model. This model opens new doors for additional studies that were not possible earlier.

Intratumoral acetic acid injection eradicates human prostate cancer tumors in a murine model.

INTRODUCTION: To treat localized prostate cancer without substantial morbidity, an ideal treatment would be an effective local therapy with minimal morbidity. Direct injections have been used to treat benign prostatic hyperplasia without major complications, but in limited cases. We evaluated the local oncotoxic effects of acetic acid in a prostate cancer xenograft murine model. MATERIALS AND METHODS: PC3 and LNCaP human prostate cancer cell lines were used to grow subcutaneous tumors in SCID mice. For each cell line, 14 mice underwent intratumor injection with 25% acetic acid (0.05 ml/100 cm3 of tumor) after the tumor was >300 mm3. Post-treatment one mouse/group was euthanized after 2 h, 24 h, 1 and 2 weeks; remaining mice (n = 10) were killed at 120 days. Control mice (8/group) were euthanized after they met the humane criteria for tumor burden and overall health. RESULTS: Tumor necrosis was noted immediately post-injection; by 24 h, ulceration and crusting of overlying skin were noted, which healed into scars by 23 ± 5 days. Histological examination showed tumor degeneration and necrosis with blood vessel obstruction. Ten treated mice in both groups survived for 120 days, which was much longer than the mean survival of PC3 (40 ± 9 days) and LNCaP (56 ± 10) control mice. CONCLUSIONS: Direct injection of acetic acid successfully eradicated both tumors. This treatment option could potentially be used in humans for treatment of early localized prostate cancer and nonoperative management of locally advanced cases. This is the first report of successful local chemical therapy for prostate cancer.

Clinicopathological significance of the expression of estrogen receptor-beta and vascular endothelial growth factor-A in colorectal cancer.

Estrogen-receptor-beta (ERß), progesterone receptor (PR) and vascular endothelial growth factor (VEGF-A) have been implicated in colorectal cancer. However, the clinicopathological significance of any expression of these markers remains unclear. Immunohistochemical assays of ERα, ERß, PR, and VEGF-A were performed on 72 colorectal cancer cases. Normal mucosa from the same cases was assessed as a control. The correlation of presence of these markers with clinicopathological features and survival was determined. ERα and PR were not expressed in tumors. Forty-one of 53 (77.4%) cases of normal mucosa showed strong ERß expression compared with weak expression in 32 of 72 (44.4%) of malignant cells. A significant decrease in ERß expression from normal mucosa to tumor was found in females (P = 0.007) but not in males (P = 0.149). VEGF-A was expressed strongly in malignant cells in 64 of 72 (89%) cases. No association was found between ERß or VEGF-A expression and tumor grade, angiolymphatic involvement, stage, disease-free survival, or overall survival. Colorectal cancers do not express ERα or PR. ERß may have a protective role, especially in females. VEGF-A may have a role in tumorigenesis. Nevertheless, ERß and VEGF-A cannot be used as prognostic markers.

Transvesical NOTES: survival study in porcine model.

BACKGROUND AND OBJECTIVES: The optimal access route and method for natural orifice transluminal endoscopic surgery (NOTES) has not been established. A transvesical approach, with its low rate of peritoneal contamination, is an effective clean portal of entry, but a safe urinary bladder closure has been a challenge. We developed a new technique for a safe, pure transvesical NOTES approach. METHODS: Four female piglets were used in the study. With the pigs under anesthesia, a flexible cystoscope (15Fr) was used to make an endoscopic cystotomy; diagnostic peritoneoscopy of the abdominal quadrants was done with biopsies and hemostasis. At the end, a Vicryl loop was pushed to close the bladder incision while the incision edges were pulled inwards. The pigs were euthanized after 2 wk, and necropsies were performed. RESULTS: No bowel injury was noted in any of the 4 pigs. Satisfactory bladder closure was done in 2 pigs, while a partial closure was achieved in 1 case. In the postoperative period, the pigs showed no signs of pain or distress, voided normally, and had a good appetite. On necropsy, we noted healed cystotomy incisions, no intraabdominal adhesions, and no adhesions at the site. CONCLUSION: Our new technique for endoscopic cystotomy overcomes previously reported risks for bowel injuries. Using this route gives good spatial orientation and access to all quadrants, including the pelvis. Biopsies with good hemostasis can be easily achieved. Lack of intraperitoneal changes postoperatively indicate that this procedure may be safe for humans.

A novel nonoperative orthotopic colorectal cancer murine model using electrocoagulation.

BACKGROUND: Orthotopic mouse models of human colorectal cancer represent an important in vivo tool for testing chemotherapeutic agents and studying intraluminal factors that may alter the growth of cancers. Currently the orthotopic mouse models of colorectal cancer require either an operative procedure or creation of colitis to implant the cancer cells in rectum. We have developed a nonoperative, minimally invasive technique to create a true orthotopic colon cancer mouse model. STUDY DESIGN: We used human (LS 174T and HT-29) and murine (CRL-2638 and CRL-2639) colon cancer cell lines. Low-dose mucosal coagulation was performed transanally using a specially designed electrode at 1 to 3 predetermined points, 2 to 3 cm from the anus, followed by a transanal instillation of tumor cells (1 × 10(6) cells) in 12 female nude or severe combined immunodeficiency disease mice for each of the 4 groups (n = 48, plus 16 controls). Mouse colonoscope (Coloview) and microCT were used to follow tumor growth. Four mice from each group were euthanized at 1, 2, and 3 weeks. RESULTS: Tumors were detected in 12 of 12 of the CRL-2638, 11 of 12 of the CRL-2639, 7 of 12 of the HT-29 and 12 of 12 mice in the LS 174T groups. Histopathologic evaluation showed that the tumors grew from the colonic mucosa. CRL-2638 and LS 174T exhibited better implantation, faster tumor growth, larger tumor volume, and earlier metastases. MicroCT detected tumors larger than 3 mm, and the colonoscopy detected tumors larger than 1 mm. CONCLUSIONS: Our mouse model is minimally invasive and easy to create and overcomes the limitations of existing models while mimicking the human disease in terms of morphology and biologic behavior. This model opens the doors for colon cancer oncologic studies in an animal model that were previously not possible.

Topical gentamicin does not provide any additional anastomotic strength when combined with fibrin glue.

BACKGROUND: We evaluated the effect of a combination of fibrin sealant and topical gentamicin on a colonic anastomosis in a rat model. METHODS: Partial anastomosis in the transverse colon was performed in 70 male Sprague-Dawley rats aged 6 to 10 weeks using 5 interrupted sutures. The rats were divided into 4 groups (control, gentamicin, fibrin glue, and combination). On postoperative days 3 and 5, the rats in each group were killed, anastomotic bursting pressures scores and bowel loop adhesions were determined, and histologic examination was performed. RESULTS: No significant difference was noted in the bursting pressures, adhesions, inflammatory infiltrates, fibroblasts, or neoangiogenesis between the fibrin-glue only and the combination groups for both the day 3 and day 5 subgroups. CONCLUSIONS: The combination of topical gentamicin and fibrin glue had little effect because the combination did not provide additional anastomotic strength or decrease the number of adhesions when compared with fibrin glue alone.

Protective effect of methylprednisolone on warm ischemia-reperfusion injury in a cholestatic rat liver.

BACKGROUND: Cholestasis has been identified as a risk factor for oxidative stress, and it potentially enhances after ischemic-reperfusion injury. The aim of this study was to evaluate the role of methylprednisolone on warm ischemia-reperfusion injury in the presence of cholestasis. METHODS: A reversible cholestatic rat model was created. After 7 days, rats received 30 mg/kg of intravenous methylprednisolone 2 hours before ischemia, followed by 30 minutes of ischemia. Rats were euthanized 24 hours after ischemia. Serum aspartate aminotransferase and interleukin-6 were measured, and the liver was harvested for histology and myeloperoxidase estimation. RESULTS: Methylprednisolone had a protective effect, with a statistically significant decrease in aspartate aminotransferase (P=.01) and a trend toward decreased levels of interleukin-6 (P=.07). Histology showed a significant difference in architectural distortion (P=.01), cytoplasmic vacuolation (P=.01), and nodular hepatocellular necrosis (P=.04). CONCLUSIONS: Methylprednisolone attenuated the ischemic-reperfusion injury in the presence of cholestasis and can be considered for clinical use in the presence of cholestasis.

The use of polyacrylamide gel in soft-tissue augmentation: an experimental assessment.

BACKGROUND: An increasing number of soft-tissue filler substances that lack experimental and clinical data have been introduced into plastic surgery practice outside the United States. One of these substances is polyacrylamide gel. It contains 2.5% polyacrylamide and 97.5% water. It is homogenous and stable, and has optimum viscosity and elasticity. METHODS: One milliliter of polyacrylamide gel was injected into the subcutaneous layer of the right ear in 28 rabbits. The rabbits were divided into two groups, according to when the material was harvested and evaluated. Material was harvested at 4 months in 15 rabbits and 7 months in 13 rabbits. Each group underwent volumetric ultrasound evaluation, magnetic resonance imaging, and histological evaluation with hematoxylin and eosin and CD68 staining. RESULTS: Results were easily observed because of the superficial position of the injected material. There were no systemic or local complications. The samples harvested showed a clear and jelly-like consistency similar to that of the initially injected material. The volume was constant after 6 weeks, after an initial period of acute stretching. Ultrasound volumetric analysis was also constant in all groups. At 7 months, a stable volume of 1.0 +/- 0.2 ml was observed. Magnetic resonance imaging scanning showed that the material was stable and that there was no inflammatory reaction. Histological analysis revealed a minimal foreign-body reaction, and the injected material was occasionally surrounded by a thin collagen membrane. The material remained in place. CONCLUSIONS: Polyacrylamide gel has a long-lasting effect, with minimal volume variation. It remains soft to the touch and in place.

Expression of interferon receptors in pancreatic cancer: identification of a novel prognostic factor.

OBJECTIVES: Interferons (IFNs) are known to have antiproliferative and immunoregulatory activities that are modulated through specific cellular-surface ligands, known as IFN-alpha, -beta, and -gamma receptors. The presence of these receptors and their impact on survival in patients with pancreatic cancer has not been determined. METHODS: Slides were prepared from 46 patients with pancreatic adenocarcinoma. Immunohistochemistry (IHC) was used subsequently to determine the expression of IFN-alpha/beta receptor-chain 2 (IFNalpha/betaR) and IFN-gamma receptor-chain 1 (IFNgammaR). The correlation among IFN-receptor expression, characteristics of neoplasms, and overall patient survival were determined analytically. RESULTS: The IHC performed for pancreatic adenocarcinoma demonstrated a high IFNalpha/betaR expression in 4% (2/46) of patients, moderate expression in 20% (9/46), and faint or no expression in 76% (35/46). IHC confirmed a high expression of IFNgammaR in 52% (24/46) of patients, moderate expression in 35% (16/46), and faint or no expression in the remaining 13% (6/46). A clinicopathologic survey failed to demonstrate any significant correlation between IFNalpha/betaR and IFNgammaR expression with regard to size of neoplasm, vascular or perineural invasion, lymph node metastases, or stage of disease. Kaplan-Meier survival analyses demonstrated a survival advantage in those patients whose neoplasms expressed moderate to high IFNalpha/betaR expression, compared with those with faint or no IFNalpha/betaR expression (22 vs 13 months; P = .012, log-rank test). The expression of IFNgammaR, however, had no impact on patient survival (20 months vs 17 months; P = .66, log-rank test). CONCLUSIONS: The IFNalpha/betaR is an independent prognostic factor in patients with pancreatic cancer.

The effect of gradually increased blood flow on ischemia-reperfusion injury in rat kidney.

BACKGROUND: Gradually increased blood flow to the ischemic rat kidney was studied to assess the ability to diminish ischemia-reperfusion injury. METHODS: The left renal artery and vein were isolated in 25 rats. Microclamps were applied for 45 minutes and were released at once (group II) or gradually (group III). Renal arterial blood flow and K+ activity were measured. Bilateral kidneys were harvested for histopathology and for malonyldealdehyde and myeloperoxidase levels. RESULTS: Increased K+ activity returned to preischemic values faster in group III than in group II. No statistically significant difference existed in malonyldealdehyde and myeloperoxidase levels; histopathologic scoring showed less tissue damage in group III (P < .05). Contralateral kidney samples showed signs of ischemia in group II. CONCLUSIONS: Gradually increased blood flow to the ischemic kidney decreases ischemic changes. Ischemic insult to 1 kidney causes histopathologically detectable changes to the contralateral kidney, which can be diminished by gradual reperfusion.

Gangliocytic paraganglioma arising from mature cystic teratoma of the ovary.

BACKGROUND: Gangliocytic paraganglioma is a rare neoplasm involving the small intestine, stomach, and spinal cord. Ovarian gangliocytic paraganglioma has not been reported in the medical literature. CASE: A 55-year-old caucasian woman underwent exploratory laparotomy, total abdominal hysterectomy, and bilateral salpingo-oophorectomy for evaluation of a persistent right adnexal mass. Microscopic examination of the right ovary revealed a mature cystic teratoma with a mural nodule consistent with gangliocytic paraganglioma. As there was no evidence of significant pleomorphism or neoplastic infiltration, surgical staging was not performed. CONCLUSION: Gangliocytic paraganglioma may arise from ovarian cystic teratoma. Although most cases of gangliocytic paragangliomas are benign, surgical staging and retroperitoneal lymphadenectomy may be required if histopathology is suggestive of invasive disease or if enlarged lymph nodes are noted.

Easy tissue expansion of prelaminated mucosa-lined flaps for cheek reconstruction in a canine model.

In head and neck reconstruction, there is sometimes the need for a skin flap lined with mucosa. The object of this study was to determine whether small pieces of mucosa grafted onto the undersurface of a skin flap can be expanded in a reasonable time to provide the material required to reconstruct a full-thickness cheek defect as a free flap. The study consisted of two phases: prelamination and expansion of the flap, and vascularized free-tissue transfer of the flap. Six adult mongrel dogs were used. First, a 5 x 10-cm flap based on the saphenous vessels was elevated on the lower leg, and then four 1 x 2-cm pieces of mucosa harvested from the tongue were grafted onto the undersurface of the flap. A tissue expander (5 x 10 cm) was then placed under the flap, and the incision was closed primarily. The expanders were initially filled with just enough normal saline to obliterate dead space immediately after surgery. The expansion was continued twice weekly for 3 weeks until sufficient expansion was obtained. Two of six flaps were followed for an additional 6 weeks after the 3-week expansion period to observe whether additional mucosa could be obtained. After measurement of the mucosal area, each flap was transferred as free flap to reconstruct an iatrogenic cheek defect. The increase of mucosal surface area was compared with the original graft, and differences were analyzed using the paired t test. All flaps were successfully expanded without any complications. Histologic evaluation revealed that grafted mucosa took well without evidence of graft necrosis, and the intergraft area was covered with histiocytes. Angiography revealed well-defined vascular structures covering the entire area of the flap. The new mucosal area (23.5 +/- 2.4 cm2) was significantly larger than the original mucosal graft (8.7 +/- 0.9 cm2) (p < 0.001). The net increase of the mucosal area was 172.9 +/- 32.4 percent. The increase of mucosal area in two flaps, following a 6-week consolidation period after 3 weeks of expansion, was only slightly greater (25.9 +/- 1.3 cm2) than those without the consolidation period (22.3 +/- 1.8 cm2). This increase of the mucosal area appears to be related to the amount of expansion, and not to the length of the consolidation period. The flaps were successfully transferred as free flaps to reconstruct the full-thickness cheek defects without major complications. Although a staged operation to allow flaps to mature is needed, the present procedure has the advantages of providing a mucosa-lined flap and allowing primary closure of the donor site. The authors conclude that expansion of this flap has great potential in reconstructive surgery.