Therapy of peritoneal carcinomatosis of human colon cancer xenografts with yttrium 90-labeled anti-carcinoembryonic antigen antibody ZCE025

The present study was undertaken to determine whether an anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAB), labeled with the potent beta emitter yttrium 90, could alter the growth of diffuse intraperitoneal carcinomatosis of colon cancer. Nude mice bearing the CEA-producing human tumor line LS174T received therapy with the anti-CEA MAB ZCE025 90Y. Animals were evaluated 12 days after therapy. Untreated animals had a mean (+/- SEM) tumor burden of 3.99 +/- 0.10 g, while animals treated with ZCE025 90Y had 0.29 +/- 0.04 g present. This decrease was significant compared with the 1.31 +/- 0.16 g of tumor present in animals treated with a 90Y-labeled nonspecific antibody 96.5c. The therapeutic effects seen with ZCE025 90Y suggest a potentially useful role for 90Y-labeled anti-CEA MABs in the treatment of gastrointestinal carcinomatosis.     

A proteinase inhibitor decreases tumor growth in a laparoscopic rat model

BACKGROUND: The balance between proteolysis and protease inhibition in the formation and breakdown processes of the extracellular matrix plays a major role in tumor cell invasion. An understanding of this relationship gave rise to the therapeutic concept of lowering tumor cell invasion by inhibiting protease activity. Phosphoramidon is an unspecific proteinase inhibitor. This experimental study investigated the effect of intraperitoneal phosphoramidon administration on tumor growth in a laparoscopic rat model. METHODS: In the first phase of the study, we investigated the influence of phosphoramidon on tumor cell invasion in a collagen matrix gel chamber in vitro. In a second experiment, a suspension of colon carcinoma cells (CC531) was introduced into the peritoneal cavity of male WAG rats. Prior to laparoscopy (at 6 mmHg for 20 min), the animals were randomized to two groups. At the start of laparoscopy, the test substance was applied intraperitoneally (group 1: controls, 1 ml 0.9% NaCl; group 2: 250 mg phosphoramidon in 1 ml 0.9% NaCl). Three weeks after the injection of tumor cells, the animals were autopsied and the tumor mass determined. RESULTS: In comparison with the control group (tumor weight 7.42 +/- 1.01 g), intraperitoneal tumor growth in the experimental group was significantly (p < 0.001) reduced by the application of phosphoramidon (tumor weight, 3.22 +/- 1.06 g). Phosphoramidon also significantly (p < 0.05) reduced tumor cell invasion through the matrix gel. Conclusion: The proteinase inhibitor phosphoramidon reduced tumor cell invasion in vitro and tumor cell growth in vivo in this laparoscopic rat model.     

Experimental assessment of tumor growth and dissemination of a microscopic peritoneal carcinomatosis after CO2 peritoneal insufflation or laparotomy

BACKGROUND: Based on clinical observations and previous animal studies, laparoscopic surgery for malignant disease is regarded as controversial. We used a rat model to measure and compare the tumor growth, proliferation, and dissemination of a microscopic peritoneal carcinomatosis after CO(2) intraperitoneal insufflation or laparotomy. METHODS: Peritoneal carcinomatosis was induced in three groups of 27 BD IX rats each with intraperitoneal injections of 106 DHD/K12 cells, an aneuploid tumor cell line. At 48 h after tumor cell injection, the animals were randomly divided into three groups to undergo different types of intervention. All animals were anesthetized for 20 min (Halothane). The control group had no surgical intervention (group C), group I had CO(2) insufflation (7 mmHg),and group L had a midline laparotomy (5-cm). Neither bowel manipulation nor any other traumatic action was performed. Two weeks later, the rats were killed and the incidence, type, and dissemination of carcinomatosis were evaluated. We also measured the tumor's weight. Malignant omentum was sampled for flow cytometry analysis (DNA ploidy, S-phase fraction). RESULTS: The incidence of carcinomatosis did not differ among the groups. The mean score of macroscopic characteristics of the carcinomatosis was 2.8 +/- 1.9 in group L, 2.9 +/- 1.9 in group I, and 3 +/- 1.9 in group C (NS). The location of the implants did not differ, except for parietal peritoneum location, which was more frequent in group L (p < 0.01). The tumor weight was 4.96 g +/- 3.2 in group L, 5.55 g +/- 3.2 in group C, and 5.75 g +/- 3.4 in group I (NS). The percentage of aneuploid cells and S-phase fraction did not differ statistically among the groups. Conclusion: These results indicate that CO(2) insufflation does not cause more effects than laparotomy when tumors cells are present before the beginning of the surgery. Further studies are needed to determine the influence of other steps in laparoscopic surgery on tumor growth and dissemination.     

Effects of laparoscopy on intraperitoneal tumor growth and distant metastases in an animal model.

BACKGROUND AND AIMS: Laparoscopic surgery for colorectal cancer is currently being evaluated in humans. The aim of this study was to examine the effect of laparoscopy on intraperitoneal tumor growth and distant metastases in an animal model. We also examined the effect of combining laparotomy with laparoscopy and on infusing the peritoneal cavity with normal saline solution (NaCl), water, and sodium hypochlorite after laparoscopy on intraperitoneal tumor growth. MATERIAL AND METHODS: Female Fischer rats were given MtLn3 adenocarcinoma cells by intraperitoneal injection to produce intraperitoneal tumor growth and by tail vein injection to produce lung metastases. A pneumoperitoneum was then induced to a pressure of 8 mm Hg with carbon dioxide (CO2), helium, or room air. After this, animals were allowed to either recover or underwent laparotomy or infusion of NaCl, water, or sodium hypochlorite before recovery, depending on the experiment. At 21 days all animals were killed and intraperitoneal tumor growth was assessed by counting the number of peritoneal and serosal nodules and by weighing the omental pad of tumor. Lung metastases were assessed by counting the number of metastases after fixation. RESULTS: Laparoscopy caused a marked intraperitoneal dissemination of tumor with a median of 17 (10 to 20) peritoneal and serosal nodules for CO2, 19.5 (12.5 to 25) for helium, and 15.0 (9.5 to 17.7) for room air compared with 0 (0 to 1) for controls (P < .0001). The weight of omental tumor was also significantly increased (P < .02) in the CO2, helium, and room air groups. Infusion with NaCl, water, or sodium hypochlorite had no effect on tumor dissemination after laparoscopy. The combination of laparoscopy and laparotomy caused a significant reduction (P < .05) in the number of peritoneal nodules but had no significant effect on omental tumor growth. Laparoscopy also had no effect on the number of pulmonary metastases induced compared with controls. CONCLUSIONS: This study shows that laparoscopy promotes intraperitoneal dissemination of tumor. This effect is independent of the insufflating gas used and is not affected by use of a cytotoxic agent. The use of gasless laparoscopy should be encouraged by those undertaking curative laparoscopic surgery for colorectal cancer.     

In vivo mapping of pulmonary lymphatic pathways: a new technique.

Recently we reported on a simple method of tracing the regional lymphatic drainage of the tracheobronchial tree using radiocolloids in patients undergoing bronchoscopy. The specificity and accuracy of the technique were evaluated in a series of canine experiments. Using a rigid bronchoscope and a long injecting needle, a mixture of 0.5 cc of radioactive colloid (200 μCi ¹⁹⁸Au, 2 mCi ^99mTc sulfur colloid, or 2 mCi ^99mTc antimony sulfide), and 0.5 cc of a colored colloidal marker (trypan blue) was injected submucosally in selected bronchial regions in a series of five dogs. Four hours after injection the distribution of the injected radioactivity was demonstrated by scanning with a gamma camera. The animals were killed and autopsies performed. Thoracic lymph node dissections showed the distribution of the colored colloidal marker. This was compared with the radioactivity of the lymph nodes which had been excised and counted in vitro with a scintillation counter. The radioactivity of histologically proven lymphatic tissue was compared with that of adjacent nonlymphatic tissue. The study showed that 95% of the most radioactive lymph nodes found on scintillation counting were visualized on scanning with the gamma camera. On the other hand, in the early part of the study, not all radioactivity visualized with the gamma camera could be accounted for on scintillation counting of excised lymph nodes. With technical refinement in the latter experiments lymph nodes were found to account for 100% of the images found on scanning. On histological examination the radioactivity was found to be concentrated in lymphatic tissue. This study demonstrates that: (1) Radioactive spread following injection is located in the lymph nodes, (2) In vitro mapping of primary lymphatic drainage patterns of regional bronchi is feasible, and (3) Lymph node patterns visualized on scanning may help in surgical lymph node dissections.     

Stereotaxic implantation of dispersed cell suspensions into brain. A systematic appraisal of cell placement and survival

The application of several recent advances in cell biology, brain implantation, and cell-mediated tumor immunotherapy requires successful and reproducible placement of viable cell suspensions into brain. Stereotaxic implantation is being used to inject cytotoxic lymphocytes into gliomas and to replace dopaminergic cells in parkinsonian models. Systematic assessment of the factors that influence success in implantation of cell suspensions into solid tissues is needed. A model was developed for investigation of stereotaxic implantation using radiolabeled rat lymphokine-activated killer (LAK) cells. Anesthetized rats received microliter injections of cell suspension into the right caudate nucleus. The injection volume, cell concentration, infusion rate, and needle size were varied systematically. The animals were sacrificed 1 hour after injection; the brain was removed and sectioned, and the radioactivity was counted. Three aliquots of the suspension were injected into counting tubes for control analysis. Recovery of radioactivity was expressed as the percent of mean counts per minute (cpm) in the right frontal lobe/mean cpm in the three control tubes. To assess the viability of implanted cells, the right frontal region was mechanically dissociated in media and centrifuged, and the pellet and supernatant were counted. By using small needles and slow infusion of volumes of 10 microliters or less, 85% to 90% of the radioactivity was recovered in the caudate nucleus. At least half of the implanted cells were viable. Consistent, accurate implantation of dispersed cells into brain over a range of volumes, cell concentrations, infusion rates, and needle sizes was achieved.     

An assessment of prolonged reactivity of seven monoclonal antibodies against CX-1 tumor xenografts using a hand-held gamma-detecting probe

The biodistribution and kinetics of 7 monoclonal antibodies (MAb) with known reactivity against CX-1 tumor were examined over 21 days using a hand-held gamma-detecting probe (Neoprobe system). Twenty-eight immuno-deprived (athymic) nude mice implanted with human colon adenocarcinoma CX-1 xenografts were injected intraperitoneally with 50 microCi of 125I-labeled antibodies (4 mice/antibody). Of the 7 monoclonal antibodies, 4 were anti-CEA (MA, MB, MC, and MD), 2 were anti-TAG 72 (B72.3 NCI and B72.3 fermented) and one was anti-colorectal cancer (17-1A). Daily probe counts were recorded in duplicate over the tumor site and the contralateral nontumor site (background), and tumor-to-background (Tu/Bkg) ratios were calculated. Animals were sacrificed on day 21, and blood, heart, liver, spleen, lungs, kidneys, intestine, muscle, and the tumor were removed for gamma well counting. All antibodies identified the tumor as early as 24 h postinjection and specific tumor localization improved over time. Patterns of prolonged tumor binding varied considerably from one antibody to another, although all but one (MB) showed continuously increasing Tu/Bkg ratios. These data indicate progressive clearance of the antibodies from the background tissue and a persistence of labeled MAb activity in tumor resulting in improved tumor localization with increasing postinjection time.     

Combined inhibition of vascular endothelial growth factor and platelet-derived growth factor signaling: effects on the angiogenesis, microcirculation, and growth of orthotopic malignant gliomas

OBJECT: The goal of this study was to determine the effects of SU6668, a polyvalent receptor tyrosine kinase inhibitor against vascular endothelial growth factor receptor-2, platelet-derived growth factor receptor-beta, and fibroblast growth factor-1 on tumor growth, angiogenesis, and microcirculation in an orthotopic malignant glioma model. METHODS: Fluorescently labeled C6 malignant glioma cells were implanted into a long-term cranial window, which had been prepared in nude mice. The animals were treated with intraperitoneal injections of SU6668 (75 mg/kg/day) immediately (five animals) or 7 days (five animals) following tumor implantation. Control mice received intraperitoneal injections of vehicle (50 microl dimethylsulfoxide) immediately (five animals) or 7 days (four animals) after tumor implantation. Tumor growth, angiogenesis, and microcirculation were assessed by performing intravital fluorescence videomicroscopy over a 14-day observation period. To assess the effects of SU6668 on overall survival, C6 glioma cells were implanted stereotactically into the brains of 24 additional animals and treatment was initiated on Day 7. In both the immediate and delayed experimental setting, SU6668 treatment resulted in a significant reduction of total and functional tumor vessel densities (both p < 0.05), reflecting a suppression of angiogenesis and impairment of tumor perfusion. As a consequence, tumor growth was significantly inhibited (p < 0.05). Histological analysis demonstrated reduced tumor growth and less mass effect on the adjacent brain of treated animals. The survival experiments confirmed the importance of our results in that survival was significantly prolonged following SU6668 therapy (p < 0.05). CONCLUSIONS: Targeting of multiple angiogenic signaling pathways by polyvalent tyrosine kinase inhibitors represents a promising strategy to interfere with the vascularization, microcirculation, and growth of angiogenesis-dependent tumors. This also applies to malignant gliomas, despite the uniqueness of the cerebral microenvironment and the singular pathobiology of this tumor entity.     

Influence of gastrointestinal hormones on tumor microcirculation of experimental pancreatic cancer in the rat

BACKGROUND/AIMS: Gastrointestinal hormones influence the microcirculation in the normal pancreas. In the present study, we studied the effect of cerulein and somatostatin on pancreatic cancer microcirculation after orthotopic and nonorthotopic tumor implantation. METHODS: In 36 male Lewis rats (150-180 g) induction of a ductlike pancreatic cancer was achieved by intrapancreatic or intraperitoneal tumor fragment interposition between two inert transparent polymethyl methacrylate plates. After 4 weeks, intravital microscopy of the tumor microcirculation was performed in a temperature-controlled immersion chamber. The animals received 5 microg/kg cerulein or 3 mg/kg somatostatin for 1 h intravenously. The erythrocyte velocity in normal pancreatic capillaries or in tumor vessels was measured. RESULTS: The erythrocyte velocity in the capillaries of the normal pancreas was 1.01 +/- 0.11 mm/s at baseline and increased to 1.64 +/- 0.09 mm/s after cerulein stimulation (p = 0.007). Pancreatic cancer vessels demonstrated no increase in erythrocyte velocity after orthotopic (baseline 0.95 +/- 0.14 mm/s, after 1 h 0.86 +/- 0.13 mm/s; n.s.) and nonorthotopic tumor implantation (baseline 0.91 +/- 0.12 mm/s, after 1 h 0.95 +/- 0.14 mm/s; n.s.) after cerulein stimulation. Somatostatin decreased the erythrocyte velocity both in normal pancreas (baseline 0.87 +/- 0.02 mm/s, after 1 h 0.60 +/- 0.07 mm/s; p = 0.01) and in pancreatic cancer (baseline 0.85 +/- 0.20 mm/s, after 1 h 0.63 +/- 0.18 mm/s; p = 0.02) after orthotopic tumor implantation. There was no effect of somatostatin after nonorthotopic tumor implantation (baseline 0.90 +/- 0.10 mm/s, after 1 h 0.88 +/- 0.14 mm/s; n.s.). CONCLUSION: These data suggest that pancreatic cancer microcirculation lacks physiological blood flow control by stimulatory hormones, in contrast to the normal pancreas.     

An Assessment of Prolonged Reactivity of Seven Monoclonal Antibodies Against CX-1 Tumor Xenografts Using A Hand-Held Gamma-Detecting Probe

The biodistribution and kinetics of 7 monoclonal antibodies (MAb) with known reactivity against CX-I tumor were examined over 21 days using a hand-held gamma-detecting probe (Neoprobe system). Twenty-eight irnmuno-deprived (athymic) nude mice implanted with human colon adenocarcinoma CX-1 xenografts were injected intraperitoneally with 50 µCi of¹²⁵I-labeled antibodies (4 mice/antibody). Of the 7 monoclonal antibodies, 4 were anti-CEA (MA, MB, MC, and MD), 2 were anti-TAG 72 (B72.3 NCI and B72.3 fermented) and one was anti-colorectal cancer (17-1A). Daily probe counts were recorded in duplicate over the tumor site and the contralateral nontumor site (background), and tumor-to-background (Tu/Bkg) ratios were calculated. Animals were sacrificed on day 21, and blood, heart, liver, spleen, lungs, kidneys, intestine, muscle, and the tumor were removed for gamma well counting. All antibodies identified the tumor as early as 24 h postinjection and speciJic tumor localization improved over time. Patterns of prolonged tumor binding varied considerably from one antibody to another, although all but one (MB) showed continuously increasing TulBkg ratios. These data indicate progressive clearance of the antibodies from the background tissue and a persistence of labeled MAb activity in tumor resulting in improved tumor localizution with increasing postinjection time.     

Effects of suramin on anastomotic colon tumors in a rat model.

BACKGROUND: The development of antiangiogenic drugs offers new promise in the treatment of malignancy. Suramin has been reported to inhibit tumor growth by blocking angiogenesis and has been used in clinical trials. The aim of the present study was to examine the effects of suramin on colonic anastomotic tumors in the rat. METHODS: (a) Colonic anastomotic tumor was induced in 120 WAG/RIJ rats. Half of the animals were given 100 mg/kg of suramin intraperitoneally at the time of tumor induction. Rats were sacrificed after 2, 4 and 8 weeks; tumor take and tumor weight were evaluated. (b) The number of red blood cell clusters per x 400 field was counted in each tumor. (c) A lymphocyte transformation test was performed in four groups of animals, 2 weeks before and 2 weeks after tumor implantation and/or suramin administration. RESULTS: (a) A significant enhancement of tumor growth was observed in the suramin-treated animals. (b) This was accompanied by a significant increase in functional blood vessels. (c) Suramin-treated rats had markedly decreased lymphocyte stimulation, pointing to a possible immunosuppressive effect. CONCLUSIONS: The growth of an anastomotic colon tumor is rather enhanced by a single intraperitoneal administration of 100 mg/kg suramin in the rat, possibly by an unexpected immunosuppressive effect.     

Intraperitoneal hypothermia during surgery enhances postoperative tumor growth

BACKGROUND: Recent work has shown that intraoperative hypothermia is a significant source of surgical trauma, with wide-ranging physiological and immunological sequelae. The aim of this study was to examine the effects of intraperitoneal hypothermia during laparoscopy on tumor growth in an animal model. METHODS: Thirty WAG rats were randomized to undergo anesthesia alone (n = 10), insufflation with cold carbon dioxide (CO2) (n = 10), or insufflation with warm CO2 (n = 10). During insufflation, 1 x 105/ml CC531s colon cancer cells in suspension were injected into the peritoneal cavity. The control group was anesthetized and tumor cells were injected without insufflation. After 3 weeks, total tumor weight and the extent of tumor spread, as assessed by the modified Peritoneal Cancer Index (PCI), were compared at autopsy. RESULTS: Laparoscopy with cold CO2 resulted in a significant reduction in local and core body temperatures (p <0.05). Tumor growth in both groups that underwent CO2 pneumoperitoneum was significantly increased compared with the group that did not (p <0.0001, control vs warm CO2 and cold CO2). There was significantly more tumor growth in the rats insufflated with unwarmed CO2 than in the normothermic group (mean total tumor 0.01 g +/- 0.03 vs. 0.043 g +/- 0.07; p = 0.025 Mann-Whitney U test). Tumor spread as shown by the PCI scores was less in the warm gas group than it was in the animals insufflated with cold gas (151 vs 266). CONCLUSIONS: These data demonstrate that the peritoneal insufflation of CO2 enhances tumor growth and that the prevention of perioperative hypothermia during laparoscopy attenuates tumor growth. This effect may be partially mediated by the increased peritoneal trauma that results from insufflation with cold gas.     

Effects of class I heparin binding growth factor and fibronectin on platelet adhesion and aggregation.

Fibronectin and heparin binding growth factor-type 1 have been affixed to vascular graft surfaces to enhance the attachment and the proliferation of transplanted endothelial cells, respectively. The current study examines the effect of fibronectin and heparin binding growth factor-type 1 on platelet adhesion and activation in vivo and on platelet aggregation in vitro. Expanded polytetrafluoroethylene prostheses (5 cm x 4 mm internal diameter) were treated either with fibronectin (n = 9), fibronectin/heparin/heparin binding growth factor-type 1/heparin (n = 12), or neither (n = 13) and were interposed into canine aortoiliac systems bilaterally. Autogenous radiolabeled (Indium 111 oxine, 650 microCi) platelets were injected intravenously before reestablishment of circulation. Perfusion was maintained for 30 minutes, and prostheses were removed with segments of native aorta and distal iliac arteries bilaterally. Specimens were examined for thrombus-free surface area, by gamma well counting for adherent radiolabeled platelets, and by light microscopy and transmission and scanning electron microscopic techniques. Results showed that both the fibronectin and fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained significantly greater numbers of platelets and adherent radioactivity than did control graft segments when normalized to their ipsilateral iliac arteries. Fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained 27 +/- 16 times more radioactivity per square millimeter than ipsilateral iliac arteries, fibronectin pretreated prostheses had 13 +/- 8 times more radioactivity per square millimeter than ipsilateral iliac arteries, and untreated expanded polytetrafluoroethylene had 4 +/- 3 times more radioactivity per square millimeter than ipsilateral iliac arteries. Fibronectin/heparin/heparin binding growth factor-type 1/heparin was more radioactive than fibronectin alone (p = 0.056). Histologic evaluation and thrombus-free surface area determinations corroborated the gamma well counting data. Platelet aggregation in vitro was not activated by either fibronectin (1 to 100 micrograms/100 microliters) or heparin binding growth factor-type 1 (25 to 2500 ng/100 microliters). These data suggest that fibronectin and heparin binding growth factor-type 1 promote platelet adhesion not aggregation.     

New therapeutic strategies to avoid intra- and extraperitoneal metastases during laparoscopy: results of a tumor model in the rat

BACKGROUND: Therapeutic strategies to prevent port site recurrences in laparoscopy surgery of malignancies have not been investigated until now. METHODS: The effects of taurolidine, heparin, and povidone iodine on the growth of rat and human colon adenocarcinoma as well as gallbladder carcinoma were investigated in vitro. Furthermore, cytokine release of growth-stimulating IL-1beta by peritoneal macrophages was measured after incubation with carbon dioxide and additional incubation with the different agents. In the third experiment, prevention of intra- and extraperitoneal metastases by intraperitoneal instillation of the different agents during laparoscopy was investigated in a colon carcinoma model in the rat. Tumor cells were administered intraperitoneally in 100 rats, and pneumoperitoneum (8 mm Hg) was established over 30 min with carbon dioxide. Rats received either tumor cells, cells + heparin, cells + povidone iodine, cells + taurolidine, or cells + taurolidine + heparin. RESULTS: In vitro, tumor cell growth decreased after incubation with taurolidine, taurolidine/heparin, and povidone iodine. Cytokine release was stimulated by incubation with carbon dioxide and could only be suppressed by incubation with taurolidine in vitro. In vivo, intraperitoneal tumor weight was lower in rats receiving heparin (251 +/- 153 mg) and povidone iodine (134 +/- 117 mg) compared to the control group (541 +/- 291 mg), but even less when taurolidine (79 +/- 82 mg) or taurolidine/heparin (18.3 +/- 30 mg) were instilled. CONCLUSION: Heparin slightly inhibits intraperitoneal tumor growth in vivo, while povidone iodine and taurolidine cause a significant decrease in tumor cell growth in vitro as well as intraperitoneal tumor growth in vivo. Cytokine release of peritoneal macrophages is only suppressed by taurolidine. Total tumor take and trocar metastases are only suppressed by taurolidine and taurolidine/heparin. Copyright Copyright 1999 S. Karger AG, Basel     

Radioisotope lymph node mapping in nonsmall cell lung cancer: can it be applicable for sentinel node biopsy?

BACKGROUND: Previous studies on intrathoracic lymph node mapping have focused on the validity of a sentinel node concept, but not on the usefulness for sentinel node biopsy. METHODS: The subjects were 15 patients clinically diagnosed with N0 nonsmall cell lung cancer. Technetium-99m tin colloid was injected into the peritumoral area 1 day preoperatively and a time course of tracer migration was monitored by scintigraphy. A hand-held gamma probe counter was used to count the intrathoracic lymph node stations. Resected nodes were also counted to assess the accuracy of the intrathoracic counting. RESULTS: Serial scintigraphies showed that the tracer migrated through airways and the appearance resembled hot nodes. On intrathoracic counting, 50% of the nodal stations appeared positive; however, only 23% of these apparently positive nodal stations were ultimately shown to be truly radioactive. The true positive and true negative rates of detecting intrathoracic hot nodes were 100% and 56%, respectively. Because the counts of the nodal stations could include the counts from the hot primary tumor ("shine-through") or airway radioactivity, legitimate hot nodes were identified after dissecting all the apparently positive nodal stations. Two of the 9 patients in whom hot nodes were identified had nodal metastatic disease and actually had tumor cells within the hot nodes. The only complication related to the preoperative injection of technetium-99m was a minor pneumothorax. CONCLUSIONS: Although radioisotope intrathoracic lymph node mapping is safe, it appears to be unsuitable for sentinel node biopsy because shine-through and the airway-migrated radioactive tracer complicated the intrathoracic counting. Only serial scintigraphy could distinguish hot nodes from airway migration.     

The influence of adhesion prophylactic substances and taurolidine/heparin on local recurrence and intraperitoneal tumor growth after laparoscopic-assisted bowel resection of colon carcinoma in a rat model

Backgroud: The goal of the study was to investigate the influence of adhesion prophylactic substances (Interceed/lntergel) as well as taurolidine/heparin on intraperitoneal tumor growth and the local recurrence rate after laparoscopic cecum resection in a rat tumor model. Methods: Sixty BDIX rats were randomized in three therapy groups and one control group. A laparoscopic-assisted cecum resection was performed via three-trocar method after intraperitoneal tumor cell application (10,000 cells) of a colon carcinoma cell line (DHD/K1/TRb) in all animals. According to the randomization, the cecum suture and a 1 × 1-cm peritoneal defect were either covered with Intergel/Interceed or 1 ml of 0.5% taurolidine 10 IU heparin. The control group underwent instillation of 1 ml 0.9% NaCl solution. After 4 weeks the animals were euthanized and intraperitoneal tumor growth, local recurrence rate, and the number of intraperitoneal adhesions were determined. Results: The local recurrence rate was not significantly affected by any of the substances. Nevertheless, taurolidine/heparin significantly reduced the total number and weight of intraperitoneal metastases. The formation of adhesions was not significantly influenced by adhesion prophylaxis substances or by taurolidine/heparin. Conclusions: Taurolidine/heparin led to a significant reduction of intraperitoneal tumor growth after intraperitoneal application, whereas local tumor recurrence was not significantly influenced. This might be due to the number of injected tumor cells in this cell suspension model. Interceed and Intergel did not reduce intraperitoneal tumor growth. Furthermore, adhesion formation was not reduced by any of the substances.     

Do operations facilitate tumor growth? An experimental model in rats

Enhancement of tumor growth by operation is a concern often expressed by surgeons and patients anticipating cancer surgery. Two series of experiments were performed in which Fischer 344 rats and a carcinogen-induced transplantable rat colon cancer were used to test whether anesthesia and operation facilitate tumor implantation and growth. In the first experiments two groups of rats were given intraperitoneal tumor cells. One group underwent sham laparotomy; the second did not undergo surgery. In the second set of experiments rats were injected subcutaneously with tumor cells and then divided into four groups. The first group did not undergo laparotomy. The second underwent laparotomy on day 1, the third on day 15, and the fourth on days 15 and 29 after tumor implantation. Animals were followed for the incidence and growth rate of tumors that developed. The initial experiments demonstrated that 89% of the operated versus 49% of the nonoperated animals developed a tumor (p less than 0.001). The second experiment demonstrated that: animals undergoing multiple operations have a higher incidence of subcutaneous tumor nodules than nonoperated animals (p less than 0.05); animals undergoing multiple operations have a higher incidence of subcutaneous tumor nodules than animals undergoing a single operation (p less than 0.05); animals undergoing multiple operations had larger size tumor masses than the nonoperated animals (p less than 0.05) and than animals undergoing only one operation (p less than 0.04). This study supports the hypothesis that multiple operations and anesthesia may enhance tumor implantation and growth of metastases. This should be considered when designing therapy for patients with cancer.     

High-malignancy orthotopic nude mouse model of human prostate cancer LNCaP.

BACKGROUND: An animal model of human prostate cancer LNCaP demonstrating high rates of spontaneous metastasis from the orthotopic site after tumor implantation would be very valuable for mechanistic and drug discovery studies. We previously developed microsurgical techniques to implant histologically intact tumor tissues orthotopically in nude mice in order to develop high metastatic mouse models of human cancer. METHODS: Intact tissue of the androgen-dependent human prostate cancer cell line, LNCaP, was implanted on the ventral lateral lobes of the prostate gland by surgical orthotopic implantation (SOI) in a series of 20 nude mice. Mice were autopsied, and histopathological examination of primary tumors and relevant organs was done to identify and quantitate micrometastasis. RESULTS: Eighteen of 20 animals transplanted with LNCaP by SOI had tumor growth. Mean primary tumor weight in the prostate was 9.24 g at time of necropsy. Sixty-one percent of the transplanted animals had lymph node metastasis. Forty-four percent had lung metastasis. Mean survival time was 72 days, indicating a high degree of malignancy of the tumor. CONCLUSIONS: The extensive and widespread lung metastasis as well as lymph node metastasis following orthotopic implantation of LNCaP in nude mice and the short survival time provide a high-malignancy nude model of the LNCaP human prostate tumor.     

Collagen-PVP,a collagen synthesis modulator,decreases intraperitoneal adhesions

BACKGROUND: Adhesion formation in the peritoneal cavity is the most common cause of intestinal obstruction and secondary female infertility. A great effort has been dedicated to reduce adhesion formation because of the associated morbidity and its complications. MATERIALS AND METHODS: This study was designed as a before-after comparative trial and included 14 rabbits, with a weight between 300 and 500 g. All rabbits were appendectomized and 1 month later laparotomized to assess adhesion formation. Rabbits were randomized into two groups, Group I (control group), with no intervention, and Group II (experimental group), treated with an intraperitoneal sponge of collagen-polyvinylpyrrolidone (Clg-PVP). The laparotomy procedure was repeated 1 month later for a new assessment of adhesion formation and histological evaluation by H-E and Masson staining. RESULTS: Histological findings showed abundant infiltrate in the control group, which was mild in the experimental group. With the Masson stain the control group showed a significantly higher amount of collagen than the experimental group and the fibrous tissue was more compact. We found a mean number of adhesions of 3.29 +/- 1.98 for the control group, which decreased to 2.57 +/- 0.79 after the second laparotomy. For the experimental group the mean number of adhesions decreased from 1.86 +/- 0.90 to 0.71 +/- 0.49 after the second laparotomy, with no statistical difference between both groups before Clg-PVP application, but a significant statistical difference after the implantation of Clg-PVP (Student's t test; P < 0.001, two-tailed). CONCLUSION: Collagen-polyvinylpyrrolidone decreases the incidence and size of intraabdominal adhesions after secondary adhesion formation after appendectomy.     

Rate of reperfusion blood flow modulates reperfusion injury in skeletal muscle

The mechanisms of ischemia-reperfusion (I-R) injury in skeletal muscle remain controversial. We investigated the effect of the rate of reperfusion blood flow on I-R injury in an isolated in vivo canine gracilis muscle model in six anesthetized dogs. In all animals, both gracilis muscles were subjected to 6 hr of ischemia followed by 1 hr of reperfusion. During reperfusion, one gracilis artery was partially occluded to limit the rate of reperfusion blood flow to its preischemic rate (limited reperfusion, LR), while the contralateral artery was allowed to perfuse freely at a normal rate (normal reperfusion, NR). Muscle injury was quantified by histochemical staining (triphenyltetrazolium chloride, TTC) with computerized planimetry of the infarct size, and by spectrophotometric determination of technetium-99m pyrophosphate uptake. Endothelial permeability was quantified by measurement of gracilis muscle weight gain and 125I-albumin radioactivity after intravenous injection. Results are presented as the means +/- SEM, and differences are considered to be statistically significant if P less than 0.05 by Student's t test for paired data. LR resulted in significantly less blood flow (9.7 +/- 1.7 cc/min/100 g) when compared to NR (55.7 +/- 11.6 cc/min/100 g). I-R injury was significantly reduced by LR as evidenced by a decrease in TTC infarct size from 41 +/- 7% to 11 +/- 5%, and a decrease in technetium-99m pyrophosphate uptake from 512 +/- 20 to 163 +/- 44 X 10(3) counts/min/g. LR also significantly decreased the postreperfusion edema formation as evidenced by a reduction in the muscle weight gain from 27 +/- 6 to 9 +/- 1 g, and a reduction in the 125I-albumin radioactivity from 45 +/- 14 to 32 +/- 8 counts/min/g. These data suggest that the hyperemic rate of reperfusion blood flow is a significant factor in the pathophysiology of postreperfusion edema and that clinical control of reperfusion injury in skeletal muscle may be achieved by limiting the rate of reperfusion blood flow.