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Biomedical subjects

C N Gutt

Publications and source records attributed to C N Gutt.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effect of insufflation gas and intraabdominal pressure on portal venous flow during pneumoperitoneum in the rat.

BACKGROUND: Carbon dioxide, the primary gas used to establish a pneumoperitoneum, causes numerous systemic effects related to cardiovascular function and acid-base balance. Therefore, the use of other gases, such as helium, has been proposed. Furthermore, the pneumoperitoneum itself, with the concomitant elevation of intraabdominal pressure, causes local and systemic effects that have been only partly elucidated. Portal blood flow, which plays an important role in hepatic function and cell-conveyed immune response, is one of the affected parameters. METHODS: An established animal model (rat) of laparoscopic surgery was extended by implanting a periportal flow probe. Hemodynamics in the portal vein were then measured by transit-time ultrasonic flowmetry during increasing intraabdominal pressure (2-12 mmHg) caused by gas insufflation (carbon dioxide vs helium). RESULTS: The installation of the pneumoperitoneum with increasing intraperitoneal pressure led to a significant linear decrease in portal venous flow for both carbon dioxide and helium. At higher pressure levels (8-12 mmHg), portal blood flow was significantly lower (1.5-2.5-fold) during carbon dioxide pneumoperitoneum. An intraabdominal pressure of 8 mmHg caused a decrease to 38.2% of the initial flow (helium, 59.7%); whereas at 12 mmHg, portal flow was decreased to 16% (helium, 40.5%). CONCLUSION: Elevated intraabdominal pressure generated by the pneumoperitoneum results in a reduction of portal venous flow. This effect is significantly stronger during carbon dioxide insufflation. Portal flow reduction may compromise hepatic function and cell-conveyed immune response during laparoscopic surgery.

Abdomen↗
PubMed2000

CO2 environment influences the growth of cultured human cancer cells dependent on insufflation pressure.

BACKGROUND: Experimental and clinical studies, have suggested that the CO2 pneumoperitoneum influences the development of intraabdominal tumor dissemination and port site metastases. Previous experiments performed both in vitro and in vivo have proved that CO2 insufflation stimulates malignant cell growth. Therefore, we designed a study to investigate the influence of CO2 insufflation administered at different pressures on the growth of cultured human tumor cells. METHODS: Two human tumor cell lines (CX-2 colon adenocarcinoma, DAN-G pancreas adenocarcinoma) were exposed to a CO2 environment maintained at different pressures (0 mmHg, 6 mmHg, 12 mmHg). Tumor growth was determined at different times after exposure to CO2 using fluorescence photometry. Cytotoxity of the CO2 environment different pressures was investigated using flow cytometry. RESULTS: At 1-4 days after exposure to CO2 insufflation, CX-2 and DAN-G tumor cell growth was decreased significantly (p < 0.01). Proliferation of pancreatic adenocarcinoma DAN-G increased significantly from day 5 to day 15 independent of the insufflation pressure (p < 0.01). Proliferation of colon adenocarcinoma CX-2 increased significantly from day 5 to day 15 but was found to be dependent on the insufflation pressure. CX-2 growth increased significantly with higher pressures (p < 0.05). CONCLUSION: CO2 insufflation influences the growth of cultured human tumor cells. After a short period of suppression, the CO2 environment stimulates malignant cell growth. The insufflation pressure may also have additional effects in promoting tumor growth.

Adenocarcinoma↗
PubMed2000

Hepatic tumor spread of colorectal cancer in a laparoscopic animal model.

BACKGROUND: We devised a standardized animal model to study the impact of laparoscopic colorectal surgery on intrahepatic tumor cell growth. METHODS: The technique of laparoscopic surgery in the rat was extended by endoscopic inoculation of colon cancer cells (CC531) into the portal vein (1 x 10(4), 5 x 10(4), 1 x 10(5), 3 x 10(5), 5 x 10(5) cells/ml) of WAG/Rij rats (n = 25). As controls, five animals underwent laparotomy and open intraportal inoculation of 5 x 10(4) cells/ml. RESULTS: Hepatic tumor growth occurred after inoculation of 5 x 10(4), 1 x 10(5), 3 x 10(5), and 5 x 10(5) cells/ml. Extrahepatic tumor and conflating hepatic tumor was observed after the inoculation of 1 x 10(5), 3 x 10(5), and 5 x 10(5) cells/ml. Concentrations of 5 x 10(4) cells/ml injected either laparoscopically or via an open technique led to single hepatic tumor nodules. No tumor growth was seen after inoculation of 1 x 10(4) cells/ml. CONCLUSIONS: Laparoscopic intraportal tumor cell inoculation is a feasible technique to create hepatic metastases. The inoculation of 5 x 10(4) CC531 cells leads to reliable cell growth that can be used to investigate the impact of various laparoscopic techniques on tumor spread.

Adenocarcinoma↗
PubMed2000

Carbon dioxide pneumoperitoneum is associated with increased liver metastases in a rat model.

BACKGROUND: In patients with primary colorectal cancer, liver metastases are the most important indicators of prognosis and survival; the effect of laparoscopic surgery on the development of hepatic tumor spread is still largely unknown. METHODS: Thirty WAG/Rij rats were randomly divided into 3 operative groups for intraportal tumor cell inoculation: carbon dioxide pneumoperitoneum (group I, n = 10), gasless laparoscopy (group II, n = 10) and open laparotomy (group III, n = 10). The total operating time was 90 minutes with tumor cell injection (50,000 CC531 colon carcinoma cells/mL) performed 45 minutes after the start of the procedure. Hepatic tumor growth and the total tumor load were evaluated 28 days after surgery. RESULTS: Hepatic tumor growth and total tumor load were significantly reduced in the gasless laparoscopy group (group II) as compared with the carbon dioxide pneumoperitoneum group (group I) and the open laparotomy group (group III) (P < .05). No significant difference was found between the carbon dioxide and the open laparotomy groups. CONCLUSIONS: Insufflation of carbon dioxide may actually stimulate metastatic disease of the liver. Gasless laparoscopy seems to preserve hepatic resistance against tumor growth.

Animals↗
PubMed1999

Portal venous flow during CO(2) pneumoperitoneum in the rat.

BACKGROUND: CO(2) gas insufflation is routinely used to extend the abdominal wall. The resulting pneumoperitoneum has a number of local and systemic effects on the organism. Portal blood flow, which plays an important role in hepatic function and cell-conveyed immune response, is one of the affected parameters. METHODS: An established animal model (rat) of laparoscopic surgery was modified by implanting a perivascular flow probe. Hemodynamics in the portal vein were then measured during increasing intraabdominal pressure generated by carbon dioxide insufflation. RESULTS: Using this technique, an adequate flowmetry of the portal vein was achieved in all animals. The creation of a CO(2) pneumoperitoneum with increasing intraabdominal pressure led to a linear decrease in portal venous flow. CONCLUSIONS: Elevated intraabdominal pressure caused by carbon dioxide insufflation may compromise hepatic function and cell-conveyed immune response during laparoscopic surgery.

Abdomen↗
PubMed1999

Impact of laparoscopic colonic resection on tumour growth and spread in an experimental model.

BACKGROUND: The influence of surgical manipulation and carbon dioxide pneumoperitoneum on intraperitoneal tumour growth and port-site metastasis during laparoscopic colon resection is still unknown. METHODS: Some 33 male WAG/Rij rats were randomized into three experimental groups: a laparoscopy group with carbon dioxide pneumoperitoneum (n = 11), a gasless laparoscopy group (n = 11) and a laparotomy group (n = 11). After transanal injection of a tumour cell suspension (1 x 106 CC 531 cells) into the distal colon, a colon segment resection and an end-to-end anastomosis (laparoscopy; intra-abdominal technique) were performed. Tumour growth was scored semiquantitatively 24 days after the operation. Data were analysed by the Kruskal-Wallis test. RESULTS: The tumour indices from the four locations with the greatest tumour growth were significantly decreased in the laparoscopy group with carbon dioxide pneumoperitoneum compared with the gasless laparoscopy and laparotomy groups (P < 0.01). Port-site metastases were significantly decreased in the carbon dioxide pneumoperitoneum group compared with the gasless laparoscopy group (P = 0.05). CONCLUSION: A full laparotomy incision promotes greater tumour growth than does carbon dioxide pneumoperitoneum. Surgical manipulation stimulates local tumour spread more than the establishment of a carbon dioxide pneumoperitoneum.

Animals↗
PubMed1998

General oncologic effects of the laparoscopic surgical approach. 1997 Frankfurt international meeting of animal laparoscopic researchers.

The results from the majority of the reviewed studies support the hypothesis that abdominal surgery, performed via either a large incision or CO2 pneumoperitoneum, systemically encourages tumor growth in the postoperative period. A full laparotomy incision appears to have a significantly greater effect than CO2 pneumoperitoneum on postoperative tumor growth. Whether the large tumor observed in the surgical groups are the result of increased tumor cell proliferation or diminished tumor cell death remains unclear. There is some evidence pointing to both mechanisms. The loss of the postoperative tumor growth differences between the open and pneumo animals in the athymic mouse experiment suggests that cell-mediated immune function plays a role in tumor containment. The proliferation study results, however, suggest that other stimulatory influence(s) are also at work. Clearly, much research needs to be done regarding the etiology of these tumor growth differences. Other tumor cell lines need to be studied, and investigations regarding tumor growth in an intra-abdominal location need be performed as well. This body of research suggests that the manner in which the surgeon gains access to the abdominal cavity may have an impact on the propensity of tumor cells to implant, survive, and grow in the period immediately after surgery. If true, this may be the most compelling justification for the use of minimally invasive techniques for the curative resection of malignancies. However, it remains to be proven that human tumors will demonstrate differences in tumor growth similar to those noted in some of these animals models. Furthermore, it is not all clear that slight differences in tumor growth postoperatively will translate into significant differences in long-term survival or recurrence rates. At first glance, the existence of port-site tumors would appear to contradict totally the conclusions of many studies discussed in this synopsis. If laparoscopic methods are associated with decreased rates of tumor growth and establishment, then why do port-site tumors form? This is a complex issue calling for discussion that goes far beyond the scope of this article. However, several brief comment on this topic follow. The etiology of port tumors is unknown, although traumatization of the tumor during mobilization, resection, or removal is likely to play a significant role in the liberation of tumor cells from the primary. A relatively small protective benefit, in terms of slower tumor growth rates in laparoscopic patients, will likely not be sufficient to prevent a large inoculum of viable tumor cells in an abdominal wound from establishing a metastasis. Furthermore, as suggested earlier, the systemic effects on tumor growth may be different from the local (i.e., intra-abdominal or abdominal wound) effects. Finally, the true incidence of port tumors remains unknown. It has not been definitively established that the laparoscopic wound tumor incidence is significantly higher than the open rate, although this is the assumption of most surgeons. Several relatively large recently published laparoscopic series have reported port tumor incidences of 0 to 1.2%, which is in the same "ballpark" as the 0.6 1.0% abdominal wound tumor incidences mentioned in several open colectomy series. Clearly, much more research in this area is needed to understand port tumors better and to reconcile the port tumor results with the systemic tumor growth benefits that may be associated with minimally invasive methods.

Animals↗
PubMed1998

Standardized technique of laparoscopic surgery in the rat.

The evolution of advanced laparoscopic techniques requires animal models for instrument development, evaluation of the physiopathological correlation and physician training. Selection of surgical models is primarily based on cost, availability, anatomic and physiologic considerations, and housing and anesthetic methods. The use of large animals is becoming increasingly difficult due to restrictive legislation, public concern, and economic factors. A standardized technique of laparoscopic surgery in the rat has been developed to perform procedures in all abdominal regions including fundoplication, splenectomy, nephrectomy, liver resection, herniorraphy, colotomy, colectomy, and retroperitoneal exploration. The equipment consists of a specially designed small animal operating table, a standard arthroscope and micro-instruments. The rat model gives the opportunity to investigate the physiopathological relations and immune functions of laparoscopic procedures, to develop micro-instruments under realistic conditions of a live organism, and it is an excellent training model especially for pediatric and microsurgery. Besides low costs and easy availability, the rat model requires less logistic and financial efforts.

Animals↗
PubMed1998

[CO2 pneumoperitoneum inhibits in vitro proliferation of human carcinoma cells].

Up to this day, the influence of laparoscopy and hyperbaric carbon dioxide on the growth of tumor cells is not yet clear. Cells of human colonic carcinoma CX-2 and pancreatic carcinoma DAN-G were exposed to carbon dioxide under pressures of zero, 6 and 12 mmHg. Proliferation was measured by counting in NEUBAUER's counting chamber and by DNAstaining with Pico Green over five days after exposition. In a third experiment, dead cells were stained with Propidium Iodide and detected by flow cytometry. Only DAN-G after 6 mmHg showed at day five an increasing proliferation rate. Furthermore, exposition to carbon dioxide lead to an increased necrosis of cells. All other groups showed a significantly decreased proliferating activity of the cells exposed to carbon dioxide in comparison to a control group.

Air Pressure↗
PubMed1998

[Changes in portal blood flow volume by CO2 pneumoperitoneum in the rat].

To measure alterations of hemodynamics in the portal vein during increasing intraabdominal pressure due to carbon dioxide insufflation an established animal model of laparoscopic surgery in the rat was extended by implantation of a perivascular flow probe. Using this technique an adequate flowmetry of the portal vein was achievable in all animals. The installation of a CO2 pneumoperitoneum with elevating intraabdominal pressure led to a linear decrease of portal venous flow. This might compromise liver function and cell-conveyed immunoresponse in the liver during laparoscopic surgery.

Air Pressure↗
PubMed1997

Exposure of the operative field in laparoscopic surgery.

Endoscopic surgery, as a result of over 90 years of investigation, has now become the most innovative part of general surgery; every procedure in the thoracic and abdominopelvic cavity, intraperitoneal or extraperitoneal, has been reviewed for feasibility. The basic principles in the management of surgical patients, however, have not changed: adequate exposure and good lighting remain important and may become more important with endoscopic techniques. Historical review shows the dependence of advances in laparoscopy upon technical development in the field of intraabdominal exposure as the result of two objectives: namely abdominal wall displacement and bowel retraction.

Animals↗
PubMed1997

Systems and instruments for laparoscopic surgery without pneumoperitoneum.

The insufflation of carbon dioxide into the peritoneal cavity is a routine technique of abdominal exposure in laparoscopic surgery. Because of adverse physiological effects and technical disadvantages of the pneumoperitoneum, alternative methods of abdominal wall lifting have been explored recently. Two groups of retraction systems exist: intraabdominal lifting and subcutaneous lifting of the abdominal wall. Some systems require additional pneumoperitoneum, because the extent of intraabdominal exposure is not sufficient. Other systems are working completely without gas insufflation. Two systems combine abdominal wall lifting with pressure on the internal organs. Every method allows the use of standard laparoscopic instruments, which originally were designed for a regular pneumoperitoneum. The use of a low-pressure pneumoperitoneum in combination with mechanical augmentation of the peritoneal cavity reduces physiological disadvantages of laparoscopy. But technical advantages, such as combination of laparoscopic and open techniques, can be realized only without gas insufflation. Conventional instruments have been designed to fit the ergonomical needs of isopneumic laparoscopy and to be employed with simple valveless cannulae.

Humans↗
PubMed1997

The phagocytosis activity during conventional and laparoscopic operations in the rat. A preliminary study.

BACKGROUND: Numerous experimental and clinical investigations indicate that the mononuclear phagocyte system (MPS) has a relevant function in terms of physiological defense against tumor metastasis and bacterial infection. Consequently, a point of major interest is the influence of surgical techniques on the MPS function. METHOD: The model investigation examines the phagocytosis activity of the rat's MPS during conventional fundoplication (group 1, n = 10), laparoscopic fundoplication using a pneumoperitoneum (group 2, n = 10), and gasless laparoscopic fundoplication (group 3, n = 10). The MPS function is evaluated by an intravascular carbon clearance test (G. Biozzi). RESULTS: The fastest carbon elimination half-life was found in group 3. By way of contrast, there was a significant increase of carbon half-life in group 2 (p < 0.005). Even group 1 caused less MPS depression (p < 0.1) than group 2. CONCLUSION: Gasless laparoscopic procedures have a favorable effect on phagocytosis activity. The CO2 pneumoperitoneum seems to be the main reason for a decreased antigen elimination in laparoscopic treatments.

Animals↗
PubMed1997

[Initial experiences with the modular retraction system (VarioLift) for laparoscopic surgery without pneumoperitoneum].

The VarioLift system is an alternative method for abdominal wall lifting to create sufficient intra-abdominal space and adequate laparoscopic exposure to the operating field. The installation of a CO2 pneumoperitoneum is not necessary, which means that technical disadvantages, systemic and local physiological effects, or complications related to gas insufflation are not relevant when this method is used. The surgeon is allowed to combine the advantages of endoscopic surgery, such as magnified video-endoscopic visualisation, with well-known open surgical techniques to create a symbiosis of prove methods.

Equipment Design↗