Development of an ultrasonically activated trocar system

BACKGROUND

Although rare, visceral and vascular injuries related to the insertion of conventional laparoscopic trocars may have disastrous consequences. Most of these injuries are due to the high puncture force applied to the trocar. We present the results of an animal laboratory evaluation of a newly developed ultrasonically activated trocar.

METHODS

A total of 40 punctures were made in four pigs with an average weight of 53 kg. An 11-mmHg pneumoperitoneum was created through a Veress needle. A 10-mm diameter trocar was inserted in the midline for a laparoscope. A series of five trocars were then inserted on each lateral wall under laparoscopic control. Twenty punctures were made with a conventional reusable 11-mm trocar (CT) whose tip was sharp and conical. Twenty punctures were made with an 11-mm ultrasonically activated trocar (UT), whose fequency was 23.5 KHz and amplitude 150 mm. The cutaneous incision was made large enough so that the skin did not interfere with the trocar insertion. The force applied to the trocar was measured with a push-pull gauge connected to a computer. The following data were recorded: maximal force applied to the trocar to obtain insertion of the tip through the abdominal wall, maximum abdominal pressure increase during trocar insertion, and time for abdominal penetration.

RESULTS

The average time needed for trocar penetration was 12.8 s with CT and 4.5 s with UT (p < 0.001). The average maximal force was 6.8 kgF with CT and 0.4 kgF with UT (p < 0.001). The average abdominal pressure increase was 7.6 mmHg with CT and 0.8 mmHg with UT (p < 0.001). At 30 days, no necrosis was found. Pathological findings were similar in both groups.

CONCLUSION

Ultrasonically activated trocars required less time and much less force to be inserted. This may be a breakthrough in the safety of trocar insertion.

[Analysis of the action of dextran sulfate as a prophylaxis for peritoneal cancer metastasis, and its acting mechanism]

Although peritoneal cancer metastasis has the highest frequency of postoperative recurrence among digestive organ malignant tumors, there is no still decisive treatment. Dextran sulfate (DS) as a prophylaxis for cancer metastasis was examined with respect to its effect on cultured cells. DS was made to act on a strong adhesive neoplasm cell, and the action and acting mechanism were examined with respect to 1. readhesiveness, 2. cell cycle, and 3. gene analysis. The results suggest that: i) Once tumor cells are detached by DS, the free cells do not attach even when DS is removed, and ii) DS causes the cells to stop in the G1/G0 phase.

Acute effects of different atrial pacing sites in patients with atrial fibrillation: comparison of single site and biatrial pacing

It has been reported that a trial single site or biatrial pacing can suppress the occurrence of AF. However, its mechanism remains unclear. The study population included 32 patients with AF (n = 20: AF group), or without paroxysmal AF (n = 12: control group). The mechanism and efficacy of atrial pacing were investigated by electrophysiological studies to determine which was more effective for suppressing AF induction; single site pacing of the right atrial appendage (RAA) or distal coronary sinus (CS-d), or biatrial (simultaneous BAA and CS-d) pacing. In the AF group, AF inducibility was significantly higher with BAA extrastimulus during RAA (12/20; P < 0.0001) or biatrial paced drive (7/20; P < 0.01) than during CS-d paced drive (0/20). In the control group, AF was not induced at any site paced. In the AF group, the conduction delay and other parameters of atrial vulnerability significantly improved during CS-d paced drive. The atrial recovery time (ART) at RAA and CS-d was measured during each basic pacing mode. ART was defined as the sum of the activation time and refractory period, and the difference between ARTs at RAA and CS-d was calculated as the ART difference (ARTD). The ARTD was significantly longer during BAA pacing in the AF group than in control group (155.0 +/- 32.8 vs 128.8 +/- 32.9 ms, P < 0.05). In the AFgroup, ARTDs during biatrial (52.0 +/- 24.2 ms) and CS-d pacing (51.7 +/- 26.0 ms) were significantly shorter than ARTD during RAA pacing. The CS-d paced drive was more effective for suppressing AF induction than biatrial or RAA paced drive by alleviating conduction delay. CS-d and biatrial pacing significantly reduced ARTD compared with RAA pacing.

[Intraoperative coating of tumor surface using fibrin glue as a prophylaxis for cancer cell detachment]

With the aim of preventing cancer cells from becoming detached and spreading into the abdominal cavity by operative procedures during surgical resection of cancer infiltrating into gastrointestinal serosa, the exposed area of the serosa in mice was coated with fibrin glue, a biological tissue adhesive, prior to resection. We then determined whether the coating could reduce the detachment and spread of cancer cells during the surgical procedure, and thus be capable of inhibiting the occurrence of peritonitis carcinomatosa. In vitro experiments demonstrated that the fibrin glue uniformly and strongly coated the exposed area of cancer, and furthermore, that the presence of fibrin glue coating significantly reduced the number of cancer cells which became detached. As a result of using this glue, the number of deaths due to peritonitis carcinomatosa among assay mice was significantly decreased. It is therefore considered that coating the exposed area of cancer with fibrin glue inhibits cancer cells from being detached and spread during an operation, and thus can be an effective means of preventing the recurrence of peritonitis.

[Usefulness of local administration of methotrexate bound to activated carbon particles (MTX-CH)]

We developed a new dosage formulation, methotrexate bound to activated carbon particles (MTX-CH), and used it to reduce tumors via its long-acting effect at the administration sites. MTX-CH was injected locally into tumors on the back of BALB/c mice, 30 mg/mouse, as MTX and compared with mice treated with MTX aqueous solution, saline solution, activated carbon particles (CH-40) and non-treated mice. The MTX concentration at the administration sites was higher in the MTX-CH group than in the MTX aqueous solution group. A marked effect on the control of tumor growth by MTX-CH was noted after repeated administration (every 3 days, total 4 times) throughout the observation period. Although tumor size was not reduced, necrosis was microscopically observed around the site of MTX-CH administration. For the reasons mentioned above, MTX-CH is superior to MTX aqueous solution in terms of long-acting effect at the administration sites and the control of tumor growth.

Phenanthropyran derivatives from Phalaenopsis equestris

Two phenanthropyran derivatives, 3-methoxy-2,7-dihydroxy-5H-phenanthro[4,5-bcd]pyran and 2,3,7-trihydroxy-5H-phenanthro[4,5-bcd]pyran were isolated from the orchid Phalaenopsis equestri. Their chemical structures were elucidated from spectroscopic (NMR, MS etc.) analyses.

Polymerase chain reaction for detection of carcinoembryonic antigen-expressing tumor cells on milky spots of the greater omentum in gastric cancer patients: a pilot study

Our recent studies indicate that omental milky spots are frequently involved in the early stage of peritoneal cancer dissemination. We have used carcinoembryonic antigen (CEA)-specific RT-PCR for omental milky spots to predict peritoneal recurrence in gastric cancer patients. CEA mRNA was found to be positive in both 10 peritoneal washes and 16 greater omenta of 30 gastric cancer patients, including all 6 patients who showed positive results for both cytology and RT-PCR of peritoneal wash and omentum. Three of the 6 cases with positive RT-PCR in the greater omentum but not in the peritoneal wash showed recurrence of peritoneal carcinomatosa within 2 years after operation. Micrometastasis on omental milky spots was histologically confirmed in 6 of 30 gastric cancer cases. Non-specific band was detected only in the omentum of 1 case of 15 benign disease (7%), but not in peritoneal washes (0%), probably due to weak expression of CEA in mesothelial cells. Our results show that CEA-specific RT-PCR targeting micro-metastases on omental milky spots is more sensitive than targeting the peritoneal wash or conventional cytology, and suggest that this method is useful for the prediction of peritoneal recurrence in gastric cancer patients.

Polymerase chain reaction for detection of carcinoembryonic antigen-expressing tumor cells on milky spots of the greater omentum in gastric cancer patients: a pilot study

Our recent studies indicate that omental milky spots are frequently involved in the early stage of peritoneal cancer dissemination. We have used carcinoembryonic antigen (CEA)-specific RT-PCR for omental milky spots to predict peritoneal recurrence in gastric cancer patients. CEA mRNA was found to be positive in both 10 peritoneal washes and 16 greater omenta of 30 gastric cancer patients, including all 6 patients who showed positive results for both cytology and RT-PCR of peritoneal wash and omentum. Three of the 6 cases with positive RT-PCR in the greater omentum but not in the peritoneal wash showed recurrence of peritoneal carcinomatosa within 2 years after operation. Micrometastasis on omental milky spots was histologically confirmed in 6 of 30 gastric cancer cases. Non-specific band was detected only in the omentum of 1 case of 15 benign disease (7%), but not in peritoneal washes (0%), probably due to weak expression of CEA in mesothelial cells. Our results show that CEA-specific RT-PCR targeting micro-metastases on omental milky spots is more sensitive than targeting the peritoneal wash or conventional cytology, and suggest that this method is useful for the prediction of peritoneal recurrence in gastric cancer patients.

Ellagic acid formation from galloylglucoses by a crude enzyme of Cornus capitata adventitious roots

The aqueous extract of acetone powder, which had been prepared from Cornus capitata 'Mountain Moon' adventitious roots, cultured in MS medium with a high concentration of Cu2+(10 microM), showed strong oxidative activity toward galloylglucoses. A compound formed from galloyglucoses, such as 1,2,3,4,6-penta-O-galloyl-beta-D-glucose and tannic acid, by the reaction with the crude enzyme solution of the adventitious roots was isolated and characterized as ellagic acid by spectrometric analyses.

An ellagic compound and iridoids from Cornus capitata root cultures

An ellagic acid derivative, 3,3'-di-O-methylellagic acid 4-(5"-acetyl)-alpha-L-arabinofuranoside, and two iridoid glucosides, 6alpha-dihydrocornic acid and 6beta-dihydrocornic acid, were isolated from Cornus capitata adventitious roots cultured in Murashige-Skoog (Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15, 473-487) liquid medium containing 10 microM CuSO(4). Three known related metabolites, i.e. stenophyllin H1, dihydrocornin and cornin were also produced in the root cultures. The chemical structures were characterized by analysis of spectroscopic data.

Genome-wide epistatic interaction analysis reveals complex genetic determinants of circadian behavior in mice

Genetic heterogeneity underlies many phenotypic variations observed in circadian rhythmicity. Continuous distributions in measures of circadian behavior observed among multiple inbred strains of mice suggest that the inherent contributions to variability are polygenic in nature. To identify genetic loci that underlie this complex behavior, we have carried out a genome-wide complex trait analysis in 196 (C57BL/6J X BALB/cJ)F(2) hybrid mice. We have characterized variation in this panel of F(2) mice among five circadian phenotypes: free-running circadian period, phase angle of entrainment, amplitude of the circadian rhythm, circadian activity level, and dissociation of rhythmicity. Our genetic analyses of these phenotypes have led to the identification of 14 loci having significant effects on this behavior, including significant main effect loci that contribute to three of these phenotypic measures: period, phase, and amplitude. We describe an additional locus detection method, genome-wide genetic interaction analysis, developed to identify locus pairs that may interact epistatically to significantly affect phenotype. Using this analysis, we identified two additional pairs of loci that have significant effects on dissociation and activity level; we also detected interaction effects in loci contributing to differences of period, phase, and amplitude. Although single gene mutations can affect circadian rhythms, the analysis of interstrain variants demonstrates that significant genetic complexity underlies this behavior. Importantly, most of the loci that we have detected by these methods map to locations that differ from the nine known clock genes, indicating the presence of additional clock-relevant genes in the mammalian circadian system. These data demonstrate the analytical value of both genome-wide complex trait and epistatic interaction analyses in further understanding complex phenotypes, and point to promising approaches for genetic analysis of such phenotypes in other mammals, including humans.

A novel dark-inducible protein, LeDI-2, and its involvement in root-specific secondary metabolism in Lithospermum erythrorhizon

Lithospermum erythrorhizon produces red naphthoquinone pigments that are shikonin derivatives. They are accumulated exclusively in the roots of this plant. The biosynthesis of shikonin is strongly inhibited by light, even though other environmental conditions are optimized. Thus, L. erythrorhizon dark-inducible genes (LeDIs) were isolated to investigate the regulatory mechanism of shikonin biosynthesis. LeDI-2, showing the strict dark-specific expression, was further characterized by use of cell suspension cultures and hairy root cultures as model systems. Its mRNA accumulation showed a similar pattern with that of shikonin. In the intact plants LeDI-2 expression was observed solely in the root, and the longitudinal distribution of its mRNA was also in accordance to that of shikonin. LeDI-2 encoded a very hydrophobic polypeptide of 114 amino acids that shared significant similarities with some root-specific polypeptides such as ZRP3 (maize) and RcC3 (rice). Reduction of LeDI-2 expression by its antisense DNA in hairy roots of L. erythrorhizon decreased the shikonin accumulation, whereas other biosynthetic enzymes, e.g. p-hydroxybenzoic acid:geranyltransferase, which catalyzed a critical biosynthetic step, showed similar activity as the wild-type clone. This is the first report of the gene that is involved in production of secondary metabolites without affecting biosynthetic enzyme activities.

Tumour-amplified kinase BTAK is amplified and overexpressed in gastric cancers with possible involvement in aneuploid formation

Our recent analysis of gastric cancers using comparative genomic hybridization (CGH) revealed a novel high frequent copy number increase in the long arm of chromosome 20. Tumour-amplified kinase BTAK was recently cloned from breast cancers and mapped on 20q13 as a target gene for this amplification in human breast cancers. In the study presented here, we analysed BTAK copy-number and expression, and their relation to the ploidy pattern in 72 primary gastric cancers. Furthermore, wild-type BTAK and its deletion mutants were transfected to gastric cancers to examine changes in cell proliferation and DNA ploidy pattern. Evaluation of 72 unselected primary gastric cancers found BTAK amplification in 5% and overexpression in more than 50%. All four clinical samples with BTAK amplification showed aneuploidy and poor prognosis. Transfection of BTAK in near-diploid gastric cancers induced another aneuploid cell population. In contrast, the c-terminal-deleted mutant of BTAK induced no effect in DNA ploidy pattern and inhibited gastric cancer cell proliferation. These results suggest that BTAK may be involved in gastric cancer cell aneuploid formation, and is a candidate gene for the increase in the number of copies of the 20q, and thus may contribute to an increase in the malignant phenotype of gastric cancer.

Rapid detection of chromosome aneuploidies by prenatal interphase FISH (fluorescence in situ hybridization) and its clinical utility in Japan

OBJECTIVE

The purpose of this study was to assess the accuracy, informative rate, detection rate, and clinical utility of prenatal interphase fluorescence in situ hybridization (FISH) analysis of amniotic fluid samples from Japanese women.

METHODS

Amniotic fluid specimens from 2,639 Japanese women were received for prenatal interphase FISH and chromosome analysis. A questionnaire was designed to evaluate FISH clinical utility by collaboration sites.

RESULTS

Based on 2,319 tested samples, the accuracy (100%), informative (94%), and detection (87.6%) rates were all high. The accuracy (100%), informative (90.2%), and detection (90.0%) rates were also remarkable in third-trimester pregnancies. We perceive significant advantages from this test regarding medical management and patient satisfaction.

CONCLUSIONS

This novel report shows that in Japan prenatal interphase FISH testing is highly informative and accurate, not only in second-trimester pregnancies but also in third-trimester pregnancies. This test provides advantages to both physicians and patients, provided that its capabilities and limitations are understood.

Shikonin derivative formation on the stem of cultured shoots in Lithospermum erythrorhizon

LITHOSPERMUM ERYTHRORHIZON: , which are capable of producing red pigments, have been established. The red pigments were formed on the stems of L. erythrorhizon shoots cultured both on solid and in liquid media without phytohormones at 25 °C in the dark. Thin-layer chromatography, high-performance liquid chromatography and ¹ H nuclear magnetic resonance analyses revealed that the red pigments which accumulated on the cultured shoots were shikonin derivatives. The effects of various basal media and phytohormones (indole-3-acetic acid, indole-3-butyric acid and kinetin) on the growth and the formation of shikonin derivatives were investigated. When the shoots were cultured on Murashige and Skoog solid medium, the addition of kinetin remarkably enhanced shikonin derivative accumulation in the shoots. However, these effects of kinetin were not observed in the liquid culture when cultured in Gamborg B5 medium. The maximum content of shikonin derivatives (2.3% as dry weight, ca. 1.5 mg/100 ml flask) was observed in the shoots cultured in phytohormone-free B5 liquid medium for 5 weeks.

Kinetics of littorine content in various developing stages of regenerates of Atropa belladonna

 Aseptically propagated regenerates were cultivated in a hydroponic apparatus, a phytotron or in the field, and their growth and littorine contents were investigated. No littorine was detected in aseptic regenerates cultured on solidified Murashige and Skoog medium, nor was it found in leaves under the three conditions tested. In roots, it was common features to all three conditions tested that littorine increased dramatically after transplantation from culture tubes and was a major alkaloid up to week 4; subsequently the littorine contents varied depending on the cultivation conditions. Roots cultivated in the field showed a marked thickening and rapid disappearance of littorine; those cultivated in the hydroponic apparatus were thin and maintained a high level of littorine for a long time. In a plant cultivated for 16 weeks in a pot, littorine content in the roots decreased with increasing root diameter.

Somatic embryogenesis and ginsenoside production of Panax ginseng in phytohormone-free medium

Embryogenic cultures of Panax ginseng were established without using phytohormones. Somatic embryos developed from the roots of an in vitro seedling and from excised leaf and petiole segments cultured in half-macro-salt strength Murashige and Skoog medium. Excised leaf and petiole segments were obtained from in vitro germinated seedlings. Plantlets were subsequently obtained from developing somatic embryos in phytohormone-free media. Shoot formation from somatic embryos was influenced by light intensity. The rate of growth and frequency of embryogenesis were improved when cut-up embryogenic tissues were inoculated into liquid media in the dark. The ginsenoside contents of a 4 year-old field-cultivated root, seedlings from zygotic embryos, somatic embryos and embryogenic tissues were determined and compared. Somatic embryos contained 1.7 times the amount of ginsenoside Rb1 and 2.3 times the amount of ginsenoside Re compared to seedlings from zygotic embryos. Ginsenoside Rd, which was absent in the seedlings derived from zygotic embryos, was detected in somatic embryos. Higher ginsenosides Rd and Rg1 levels were found in embryogenic tissues grown on solid media than in tissues grown in liquid media. The total ginsenoside yields, including the ginsenosides Rb1 and Rg1 levels, of cut-up embryogenic tissues, were higher than those of clump tissues.

High production of ginsenosides by transformed root cultures of Panax ginseng: effect of basal medium and Agrobacterium rhizogenes strains

Successful transformation of Panax ginseng was achieved when petiole segments were infected with Agrobacterium rhizogenes ATCC 15834 and MAFF 03-01724. Transformed roots were obtained after galls developed at infected sites. The root morphology, growth and ginsenoside productivity of roots transformed with different bacterial strains differed, and the roots from A. rhizogenes ATCC 15834 grew better and produced much more ginsenosides. Using the ATCC transformed root clone, various liquid culture media were tested to determine the optimum culture medium for ginsenoside production. The root growth was optimum in phytohormone-free Gamborg B5 liquid medium, however highest content of ginsenosides (a total of five ginsenosides 1.88% dry weight) was obtained when the roots were cultured in half-macro-salt strength Gamborg B5 liquid medium. Growth of the roots over a period of 8 weeks showed that their fresh and dry weight continued to increase. The ginsenoside Rb1 content was optimum after 5 weeks of culture. Ginsenoside Rc content began to decrease slightly after the third week of culture. Ginsenosides Rd and Rg1 contents fluctuated, while ginsenoside Re content continued to rise throughout the 8 weeks of culture. Ginsenoside production, however, did not peak within the 8 weeks of culture.

Effect of CO(2) pneumoperitoneum on growth of liver micrometastases in a rabbit model

Little is known about the risk of metachronous liver metastases following laparoscopic resection for gastrointestinal malignancies. The effect of CO(2) pneumoperitoneum on the growth of established liver micrometastases was investigated in a rabbit model. Male Japanese white rabbits weighing 2.8 to 3.3 kg were randomized to three groups (n = 15 per group) 3 days following intraportal inoculation of a tumor suspension containing 5 x 10(4) cells of VX(2) cancer. In the pneumoperitoneum group, insufflation with CO(2) was maintained at a pressure of 10 mmHg for 30 minutes. In the laparotomy group the abdominal cavity remained open through a 45 mm midline incision for 30 minutes; in the control group no treatment other than anesthesia was performed. Cancer nodules on the liver surface were compared among the three groups on day 17. There was no difference in the number of cancer nodules among the groups (p = 0. 72). A significant difference in the total area of cancer nodules (mean +/- SEM) was found only between the pneumoperitoneum group (696.0 +/- 177.0 mm(2)) and the control group (247.2 +/- 60.7 mm(2)) (p < 0.05). The frequency of cancer nodules larger than 3.0 mm in maximal diameter tended to be highest in the pneumoperitoneum group (p = 0.053). These results suggests that CO(2) pneumoperitoneum may promote the growth of established liver micrometastases in this animal model.

The basic helix-loop-helix-PAS protein MOP9 is a brain-specific heterodimeric partner of circadian and hypoxia factors

PAS (PER, ARNT, SIM) proteins play important roles in adaptation to low atmospheric and cellular oxygen levels, exposure to certain environmental pollutants, and diurnal oscillations in light and temperature. In an attempt to better understand how organisms sense environmental changes, we have characterized a novel member of the PAS superfamily, MOP9 (member of PAS superfamily), that maps to human chromosome 12p11.22-11.23. This protein displays significant homology to the Drosophila circadian factor CYCLE and its putative mammalian ortholog MOP3/bMAL1. Like its homologs, MOP9 forms a transcriptionally active heterodimer with the circadian CLOCK protein, the structurally related MOP4, and hypoxia-inducible factors, such as HIF1alpha. In a manner consistent with its role as a biologically relevant partner of these proteins, MOP9 is coexpressed in regions of the brain such as the thalamus, hypothalamus, and amygdala. Importantly, MOP9 is coexpressed with CLOCK in the suprachiasmatic nucleus, the site of the master circadian oscillator in mammals.

The influence of different insufflation pressures during carbon dioxide pneumoperitoneum on the development of pulmonary metastasis in a mouse model

BACKGROUND

The effects of different insufflation pressures on the development of pulmonary metastasis was investigated in a mouse laparoscopy model.

METHODS

BALB/C mice intravenously inoculated with colon 26 cells were randomized to one of five treatment groups (10 mice per group): pneumoperitoneum at different pressures of 5, 10 or 15 mmHg; full laparotomy for 60 min; or anesthesia control. Cancer nodules on the lung surface 19 days postoperatively were compared between groups.

RESULTS

(a) As compared with the control group, pneumoperitoneum at 10 and 15 mmHg and laparotomy enhanced the growth of pulmonary metastases (p < 0.01). (b) The growth of metastases also was greater in laparotomy group mice than in mice undergoing pneumoperitoneum at 5 and 10 mmHg (p < 0.05).

CONCLUSIONS

These results suggest that the effects of different insufflation pressures on the growth of pulmonary metastases are not identical, and that pneumoperitoneum with high pressure may promote pulmonary metastases similar to those with laparotomy.

Distribution of verectin in Aloe vera leaves and verectin contents in clonally regenerated plants and the commercial gel powders by immunochemical screening

Verectin antiserum raised in white rabbits was immunochemically applied to examine verectin distribution in Aloe vera leaves during growth and flowering seasons, and to quantify verectin in clonally regenerated plants and commercial A. vera gel products.

Pneumoperitoneum with carbon dioxide enhances liver metastases of cancer cells implanted into the portal vein in rabbits

BACKGROUND

Little is known about the role of the CO2 pneumoperitoneum on tumor cells that spread from the portal system into the liver during laparoscopic surgery for gastrointestinal malignancies. Therefore, we designed a study to investigate the effect of CO2 pneumoperitoneum on cancer cells implanted in the portal vein in a rabbit model.

METHODS

Immediately after intraportal inoculation of 2.5x10(5) cells of VX2 cancer, the rabbits received either CO2 pneumoperitoneum at a pressure of 10 mm Hg for 30 min (pneumoperitoneum group, n = 14) or laparotomy alone for 30 min (laparotomy group, n = 14).

RESULTS

The number (p<0.01) and area of cancer nodules (p = 0.045) on the liver surface on day 17 were greater in the pneumoperitoneum group than in the laparotomy group. The frequency of cancer nodules >3.0 mm in diameter was higher in the pneumoperitoneum group than in the laparotomy group (p<0.001).

CONCLUSIONS

Compared with laparotomy, CO2 pneumoperitoneum enhanced the development of liver metastases in this experimental model.

Influence of trocar placement and CO(2) pneumoperitoneum on port site metastasis following laparoscopic tumor surgery

BACKGROUND

The mechanisms involved in the development of port site metastasis following laparoscopic tumor surgery remain controversial. Therefore, we decided to investigate the influence of trocar placement and CO(2) pneumoperitoneum on abdominal wound implantation in relation to intraperitoneal tumor growth in a rabbit model.

METHODS

Rabbits received either CO(2) pneumoperitoneum with insertion of nine trocars (pneumoperitoneum group, n = 15), insertion of nine trocars alone (nonpneumoperitoneum group, n = 15), or nine abdominal incisions (control group, n = 13) 3 days after intraperitoneal inoculation of VX(2) cancer cells.

RESULTS

The frequency of overall wound implantation on day 17 in the pneumoperitoneum group (24.4%) and nonpneumoperitoneum group (27.4%) tended to be higher than that in the control group (15.3%) (p = 0. 06). There was no significant difference among the three groups in the growth of cancer nodules on the omentum.

CONCLUSIONS

The presence of a trocar may be a factor contributing to port site metastasis but CO(2) pneumoperitoneum appears not to be a factor.