Horizontal transfer of DNA and the "genometastasis hypothesis".
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Animals↗
Biomedical subjects
D García-Olmo
Publications and source records attributed to D García-Olmo.
Effects of perioperative treatment with TNP-470 on the resistance of colonic anastomoses in rats.
AIMS: The present study was designed to evaluate the effects of perioperative treatment with TNP-470 on the resistance of colonic anastomoses. TNP-470 is a drug that was developed as an inhibitor of angiogenesis. METHODS: A colonic anastomosis was constructed in Sprague-Dawley rats. From 4 days before surgery to 4 days afterwards, each animal received daily intraperitoneal treatment that differed according to the group to which it belonged: the control group, which received gum arabic, or the TNP group, which received 30 mg/kg TNP-470 in gum arabic. The size of the cecum and the diameters of the pre-anastomotic and post-anastomotic colon were measured at operation and 4 days after surgery, when all animals were sacrificed. At this time the presence of adhesions was also investigated. Each segment containing an anastomosis was removed and the bursting pressure (BP) and bursting wall tension (BWT) were determined. RESULTS: Loss of cecum caliber and decreases in pre-anastomotic diameter were significantly greater in the TNP group than in the control group (p = 0.017 and p = 0.004, respectively). Dilatation and obstruction of the colon were more frequent in the control group, but the difference between the groups was significant only with respect to dilatation (p = 0.005). Moreover, loss of body weight was greater in the TNP group than in the control group (p < 0.001). BP and BWT were significantly lower in animals that had received TNP-470 (p = 0.04 and p = 0.005, respectively). With respect to post-anastomotic diameter, general adhesions and adhesions to the anastomotic line, there were no statistically significant differences between the groups. CONCLUSIONS: Perioperative treatment with TNP-470, an inhibitor of angiogenesis, affects the healing and reduces the resistance of colonic anastomoses.
Anastomosis, Surgical↗
In vitro activation of macrophages by a novel proteoglycan isolated from corms of Crocus sativus L.
Saffron corms contain a proteoglycan that is highly cytotoxic on human tumor cells. The present work was undertaken to study the possible immunomodulatory and anti-invasive properties of this compound. Non-cytotoxic concentrations of this glycoconjugate promoted significant macrophage activation, detected by the release of nitric oxide. A rapid activation of protein kinase C and NF-kappaB was obtained after proteoglycan treatment, which could explain the induction of nitric oxide synthase. Proteoglycan concentrations ranging from 10-1000 ng/ml specifically promoted apoptosis of macrophages, probably triggered by their activation. This molecule did not inhibit in vitro migration or invasion of human tumor cells. Altogether these results support a plausible immuno-modulating activity for this saffron Crocus compound.
Adjuvants, Immunologic↗
Detection of genomically-tagged cancer cells in different tissues at different stages of tumor development: lack of correlation with the formation of metastasis.
Genetic detection of tumor cells in blood, lymphatic nodes or bone marrow using reverse transcription and polymerase chain reaction (PCR) is quite attractive because it allows the early diagnosis of cancer dissemination. Unfortunately, this type of detection strategy cannot be applied to solid parenchymas, because they usually share with tumor cells the mRNA markers. To avoid this impediment, we have developed an experimental model of cancer using cells with a genome-associated tag. DHD/K12-PROb cancer cells were stably transfected with pcDNA3.1CAT. Approximately 10(6) transfected cells (DHD-CAT cells) were injected subcutaneously into the chest of BD-IX rats. Animals were divided into 11 groups according to the time between injection of tumor cells and euthanasia. An additional 'untagged group' was injected with untransfected cells (DHD-Wild). Blood and tissues samples were collected after euthanasia. Macroscopic and microscopic analysis was done. To detect circulating tumor cells or their presence in peripheral organs, we performed PCR with nested primers to amplify chloramphenicol acetyl transferase-encoding (CAT-encoding) DNA sequences. The minimum number of cells that yielded detectable cells routinely was 2 in 10(6). No modification of cancer aggressiveness was observed in DHD-CAT cells. DHD-CAT cells were detected by PCR in lung from the 1st week after inoculation, in liver, spleen and kidney from the 3rd week and in the blood from the 5th week. All animals analyzed 12 weeks after injection showed lung metastases. Metastases in liver, spleen or kidney, either microscopic or macroscopic, were never detected. We have developed an experimental model of cancer based on genomic tagging of tumor cells that allows the detection of small numbers of cells in all organs and the blood. The presence of cancer cells in parenchymas detected with molecular technology does not correlate with the development of clinically relevant metastases.
Adenocarcinoma↗
Experimental evidence does not support use of the "no-touch" isolation technique in colorectal cancer.
PURPOSE: The benefits of the "no-touch" isolation technique usually performed to prevent the circulation of tumor cells are not evident. The aim of this study was to determine whether conventional surgical procedures for treatment of colon cancer could provoke the circulation of tumor cells detected by a genetic technology. METHODS: Sixteen patients undergoing resection for colorectal cancer and two patients with irresectable tumors were studied. No patient showed liver or lung metastasis. With specific primers for carcinoembryonic antigen, we used reverse transcriptase-polymerase chain reaction to analyze tumor biopsy specimens and blood samples obtained from the antecubital vein before and after surgery and from the main drainage vein of the tumor when the tumor had been extracted. Peritoneal fluid was also collected in irrecsectable cases. RESULTS: Amplification of cDNA with carcinoembryonic antigen-specific primers was achieved with all tumor biopsies and samples of peritoneal fluid. In two patients carcinoembryonic antigen reverse transcriptase-polymerase chain reaction products were detected in antecubital vein blood before surgery and in one of them also after surgery. Only in one patient (Dukes C) were carcinoembryonic antigen reverse transcriptase-polymerase chain reaction products detected from the main drainage vein of the tumor. In serial dilution experiments we determined that the limit of detection of this method was ten tumor cells in 2 ml of blood. CONCLUSION: Our data suggest that the use of no-touch isolation techniques in colorectal cancer is not justified, based on lack of evidence indicating the detachment of cells from the tumor at surgery.
Adult↗
Effects of long-term treatment of colon adenocarcinoma with crocin, a carotenoid from saffron (Crocus sativus L.): an experimental study in the rat.
We used an experimental model in the rat to examine the effects of long-term treatment with crocin, a glycosylated carotenoid from the stigmas of the saffron crocus, on colon cancer. BD-IX rats were divided into four groups: Groups G1 and G2, designated "cancer groups," were used to study the effects of crocin on the progression of colon cancer, and Groups G3 and G4, designated "toxicity groups," were used to study the effects of the treatment on metabolic processes and the parenchyma. DHD/K12-PROb cells were injected subcutaneously into the chest of Group G1 and G2 animals. From 1 to 13 weeks after inoculation, animals in Groups G2 and G4 received a weekly injection of crocin (400 mg/kg body wt s.c.). Animals in Groups G1 and G3 received no treatment. In addition, lines of animal and human colon adenocarcinoma cells (DHD/K12-PROb and HT-29) were used to perform assays in vitro to examine the cytotoxicity of crocin. Life span was extended and tumor growth was slower in crocin-treated female rats, but no significant antitumor effect was found in male rats. Acute tubular necrosis was found in all kidney samples from crocin-treated animals, but slight signs of nephrotoxicity were found by biochemical analysis of the serum. In assays in vitro, crocin had a potent cytotoxic effect on human and animal adenocarcinoma cells (HT-29 and DHD/K12-PROb cells, 50% lethal dose = 0.4 and 1.0 mM, respectively). Treated cells exhibited a remarkable loss of cytoplasm and wide cytoplasmic vacuole-like areas. In conclusion, long-term treatment with crocin enhances survival selectively in female rats with colon cancer without major toxic effects. The effects of crocin might be related to its strong cytotoxic effect on cultured tumor cells.
Adenocarcinoma↗
Tumor DNA circulating in the plasma might play a role in metastasis. The hypothesis of the genometastasis.
BACKGROUND: Clinical and experimental observations suggest that more than one pathway might be involved in the development of metastases. In the present study, we examined the presence of tumor DNA in plasma using an experimental model in which tumor cells were modified with a genome-associated tag. We also investigated whether plasma of tumor-bearing rats had any effect on cultured cells and healthy animals. METHODS: Transfected cancer cells (DHD/K12-PROb stably transfected with pCDNA3.1CAT.) were injected subcutaneously into the chest of BD-IX rats. Animals were divided into ten groups according to the time between injection of tumor cells and euthanasia. Prior to euthanasia (2-14 week), blood samples were collected by cardiac puncture. To detect circulating tumor cells and CAT-encoding DNA in plasma, we performed PCR with nested primers. Fifty samples of plasma were chosen at random to supplement the medium of fifty cultures of DHD cells for 10-12 days. PCR for the detection of CAT DNA in cells was performed approximately one to two months later. Four healthy rats received an intraperitoneal injection of plasma from a tumor-bearing rat five times at week for 4 to 6 weeks. Animals were sacrificed and samples of liver, kidney, spleen, omentum, blood and lung were processed by PCR for the detection of CAT DNA. RESULTS: Detection of CAT DNA in plasma was slightly more frequent than in the buffy-coat fraction. All surviving cultures that had been supplemented with plasma were positive at some point for CAT DNA. In all four healthy animals injected with plasma of tumor-bearing rats, the marker gene for CAT was found in extracts of lungs. CONCLUSION: Our present observation lead us to propose the following hypothesis. Metastases might develop as a result of transfection of susceptible cells in distant target organs with dominant oncogenes that are present in the circulating plasma and are derived from the primary tumor.
Animals↗
Colorectal cancer screening through detection of fecal occult blood in a controlled health zone.
AIM: to determine the viability and utility of fecal occult blood (FOB) screening (Hemoccult II) as a method for the early diagnosis of colorectal cancer in a well-controlled health area. METHODS: between February 1994 and September 1996, personal letters were sent to all persons in the Casas Ibáñez health area (Albacete) aged between 50 and 75 years (4986 persons). All the tests were read by the same team member. A clinical history was taken of persons with positive test results, and they were offered colonoscopy. If a growth was found which was suitable for endoscopic resection, this was done. If the growth was totally resected an annual check-up was advised. Malignant and partially resected premalignant growths were referred for surgical treatment. We analyzed percent participation, attendance for testing, negative and positive tests, growths diagnosed, false-positive tests and positive predictive value. RESULTS: the a participation rate was 56.25%. In the 157 colonoscopies performed, 39 neoplasic polyps and 9 cancers were found (7 of which were Dukes stage A and 2 of which were Dukes stage C-D). Sensitivity was 97% and specificity was 96%. The positive predictive value was 30.37%. The positivity rate was 6.08%, while the predictive value for cancer was 5.38% and the predictive value for adenoma was 23.35%. CONCLUSIONS: FOB screening, in our setting, proved to have a high recruitment capacity with a positive predictive value for colorectal carcinoma which was slightly higher than the value obtained in other countries of similar socioeconomic status. Furthermore, we found a significant improvement in the diagnostic stage of colorectal carcinoma at the time of resection.
Aged↗
Orthotopic implantation of colon carcinoma cells provides an experimental model in the rat that replicates the regional spreading pattern of human colorectal cancer.
Our goal was to develop an experimental model of colon adenocarcinoma based on the orthotopic implantation of tumour cells in syngenic rats which would replicate the pattern of regional spreading of human colorectal adenocarcinoma. We used cell line DHD/K12-PROb and 62 BD-IX rats with intra-caecal injection of 1 x 10(6) cells. Macroscopic and histological examinations were made at different times after injection (from 1 to 16 weeks) with particular emphasis on caecal lesions and tumours were classified according to the TNM system (UICC, 1987). Our results suggest that this model provides a step-by-step reproduction of the development of human colorectal adenocarcinoma. It also allows us to predict how long it will take to achieve a certain degree of local spreading, which is essential for the design of cancer-related experiments. Moreover, our model has the advantage that it uses immunocompetent rats, which facilitates its application.
Animals↗
Patterns of colonic motility as recorded by a sham fecaloma reveal differences among patients with idiopathic chronic constipation.
BACKGROUND: By using a technique designated sham fecaloma, we were able to identify two types of segmentary motor phenomenon: displacement motor phenomena and nondisplacement motor phenomena. The aim of the study contained herein was to evaluate for identification of patients with different types of slow-transit constipation. METHODS: Studies were performed in healthy subjects (n = 5; colonic transit time <30 hours) and in constipated patients (n = 6; colonic transit time >125 hours; normal rectoanal manometry). A Foley-type recording probe with two perfused catheters (proximal and distal) was used. A rigid sigmoidoscope was used to place the probe at the sigmoid colon. Values recorded by the distal catheter were subtracted (point by point) from the values recorded by the proximal catheter. Subtraction curves were analyzed to quantify characteristics of displacement motor phenomena (an anally directed pressure gradient) and nondisplacement motor phenomena (an orally directed pressure gradient). RESULTS: All healthy subjects had contractions during the recording session. Displacement motor phenomena were predominant (displacement motor phenomena/30 minutes = 21.2 +/- 13.2; range, 3-39). Constipated patients yielded two different patterns: three patients had a very small number of contractions, and three patients had a prevalence of nondisplacement motor phenomena, with numbers similar to numbers of displacement motor phenomena in healthy subjects. A comparison of the patterns of constipated patients revealed a statistically significant difference (P = 0.039). CONCLUSION: Sham fecaloma is a simple and safe test. Constipated patients in this study had two different patterns of colonic motility: scarce activity without haustration and normal activity without displacement motor phenomena. This method might be useful as a diagnostic tool for clarification of the pathophysiology of severe colonic motor disorders.
Adult↗
Does neostigmine have a deleterious effect on the resistance of colonic anastomoses?
The aim of the present study was to evaluate the effects of neostigmine as a final anaesthetic manoeuvre on colonic anastomoses. A colonic anastomosis was constructed in 40 Sprague-Dawley rats. The animals were divided into two groups: (1) rats receiving intravenous saline solution (placebo); and (2) rats receiving an intravenous injection of neostigmine. The size of the caecum, and the diameters of the pre-anastomotic and post-anastomotic colon were measured during the operation and 4 days after surgery, when all the animals were sacrificed. At this time, the presence of adhesions was also investigated. Each segment containing an anastomosis was removed, and the bursting pressure and bursting wall tension were determined. Loss of caecum diameter was significantly greater in group 2 than in group 1 (P = 0.03). Dilatation and obstruction of the colon were significantly more frequent in group 1 (dilatation, P = 0.01; obstruction, P = 0.047). Also, consumption of water by group 2 was greater than that by group 1 (P = 0.049). No statistically significant differences were found between the diameters of the colon (pre- and post-anastomosis), or with respect to general adhesions and adhesions to the anastomotic line. No significant differences were found between anastomotic resistance (determined in terms of bursting pressure and bursting wall tension) in the two groups. The inclusion of neostigmine in an anaesthetic protocol under experimental setting did not reduce the resistance of colonic anastomoses and did not compromise normal healing. Moreover, obstruction caused by peristaltic weakness might be prevented by the expulsion of stool that is induced by the strong contraction of the colonic smooth muscle.
Anastomosis, Surgical↗
The effects of the pharmacological manipulation of postoperative intestinal motility on colonic anastomoses. An experimental study in a rat model.
INTRODUCTION: The aim of the study was to determine the effects of pharmacological manipulation of postoperative intestinal motility on the resistance of colonic anastomoses. MATERIALS AND METHODS: Seventy-one Sprague-Dawley rats were divided into three groups: Group 1 (n = 20; colonic anastomosis+1 cc of saline solution subcutaneously, daily); Group 2 (n = 29; colonic anastomosis+1.2 mg/100 g body weight metoclopramide in 1 cc subcutaneously, daily); and Group 3 (n = 22; colonic anastomosis+2 mg/100 g body weight hyoscine N-butyl-bromide in 1 cc subcutaneously, daily). Surviving rats (20 in each group) were sacrificed 4 days after surgery and adhesions were evaluated. Each segment containing an anastomosis was removed and the bursting pressure was determined. RESULTS: The cause of death during the early postoperative period was dehiscence in 8 cases (7 in Group 2 and 1 in Group 3). General adhesion scores in Group 2 were higher than in Group 3 (P = 0.003). The score for adhesions to the anastomosis in Group 1 was higher than in Group 2, but no statistically significant difference was found. Bursting-pressure was significantly lower in Group 2 than in other groups (P = 0.001). In all cases leakage of dye was observed at the anastomosis. CONCLUSION: The use of metoclopramide (a gastrointestinal prokinetic agent) during the early postoperative period was associated with an increase in dehiscence in colonic anastomosis and, when animals survived, there was a significant decrease in anastomotic resistance. Hyoscine (an inhibitor of gastrointestinal motility) did not improve the healing of anastomoses.
Anastomosis, Surgical↗
An experimental model for the prevention of postanastomotic tracheal stenosis.
OBJECTIVE: The aim of the current study is to determine the efficiency of an external prosthesis made of expanded polytetrafluoroethylene reinforced with a continuous silicone spiral to prevent postanastomotic stenosis after surgical correction of extensive tracheal defects in rabbits. METHODS: Forty-five rabbits were used, divided into three groups of 15 animals each. Group A was the control group. Group B animals underwent resection of six-ring segments of the cervical trachea and primary anastomosis. The procedure used in group C was similar to that used in group B, but the tracheal anastomosis was supported by an external expanded polytetrafluoroethylene prosthesis. RESULTS: Direct anastomosis after resection of six tracheal rings caused anastomotic stenosis in 100% of the animals. We did not observe tracheal stenosis in any rabbit when we applied an expanded polytetrafluoroethylene tube as an external stent for the tracheotracheal suture. CONCLUSION: We conclude that an external stent can be used to prevent tracheal stenosis resulting from the resection of six cervical tracheal rings in rabbits.
Anastomosis, Surgical↗
Effects of an intra-abdominal latex (drain-like) tube on anastomotic resistance and adhesion formation in a rat model.
PURPOSE: Aim of the present study was to determine effect of a latex drain on colonic resistance and its relation to adhesion phenomena. METHODS: Forty Sprague-Dawley rats were divided into two groups (n = 20): Group 1, simple colonic anastomosis; and Group 2, colonic anastomosis with drain "ad latum." Rats were sacrificed four days after surgery, and adhesions were evaluated. Segment containing anastomosis was removed, and bursting pressure was determined. RESULTS: General adhesion scores in Group 2 were higher than in Group 1 (P = 0.002). Score for adhesions to anastomotic line in Group 1 was higher than in Group 2 (P = 0.016). Bursting pressure was significantly lower in Group 2 (Group 1, 67.90 +/- 31.39 mmHg; Group 2, 46.95 +/-1 29.69 mmHg; P = 0.034). In all cases, leakage of dye was observed at the anastomotic line. A multiple regression test was applied to both groups (40 cases), taking bursting pressure as the dependent variable and other parameters as independent variables. A strong relationship appeared to exist between anastomotic resistance and fraction of anastomotic line that was covered by the neighboring organ (P < 0.001). CONCLUSIONS: Placing a latex drain near a colonic anastomosis is associated with local inhibition of spontaneous adhesions to anastomotic line and, therefore, to significantly decreased resistance.
Anastomosis, Surgical↗
Postoperative gangrenous peritonitis after laparoscopic cholecystectomy: a new complication for a new technique.
We report a case of anaerobic peritonitis with bowel emphysema, but no hollow organ perforations, following gallbladder removal for acute acalculous cholecystitis using a laparoscopic procedure in a diabetic patient. Management consisted of profuse peritoneal irrigation and zipper laparostomy. After a long postoperative period, the patient recovered without sequelae. The patient suffered typical acute cholecystitis with empyema and a diabetic status; anaerobial flora is frequent in these cases. The patient was operated on by means of a closed technique without contact with either air or oxygen. Moreover, CO2 injection into the peritoneal cavity with this technique, along with gallbladder rupture, created an ideal medium for anaerobial growth. We suggest that acalculous cholecystitis in diabetic patients could represent a contraindication for laparoscopic cholecystectomy; alternatively, open cholecystectomy should at least be considered when gallbladder rupture occurs during laparoscopy.
Cholecystectomy, Laparoscopic↗
Correlation between pressure changes and solid transport in the human left colon.
A study was made to correlate colonic pressure changes and solid transport in six volunteers with a left terminal colostomy. A minimally deformable solid (sham fecaloma) 2 cm in diameter was placed in the colonic lumen together with three perfusion catheters connected to the exterior via a semi-rigid rod to record movement and pressure changes. The results obtained indicate the presence of two types of segmentary motor phenomena: those that cause displacement and those that do not. Both reflect synchronous pressure increments, although the Displacing Motor Phenomena exhibit an aborally-directed pressure gradient in contrast to the orally orientated gradient in Non-displacing Motor Phenomena (P = 0.003). The Displacing Motor Phenomena cause rapid exit of the solid from the colostomy, but with a short mean trajectory (4.2 cm). Thus, segmentary contractions may generate forward propulsion provided that aborally-directed pressure gradients occur. A slow aboral displacement also occurs during periods of motor quiescence. This may be explained by tonic contractions undetected by conventional manometry.
Catheterization↗
Relationship between peritoneal adhesion phenomena and the experimental resistance of colonic anastomoses: influence of omentoplasty.
The repair processes that follow surgical injury constitute the physiopathological basis of peritoneal adhesion phenomena. The aim of the present study was to investigate the influence of the peritoneal adhesion process on the resistance of colonic anastomoses during the early postoperative period. Sixty Sprague-Dawley rats were divided into three groups (n = 20 each) according to procedure: transverse colon section and anastomosis (group 1); omentoplasty performed on the anastomosis (group 2), and thin latex sheeting covering the anastomosis (group 3). The rats were sacrificed 4 days after surgery and the adhesion evaluated. The segment containing the anastomosis was removed and the bursting pressure determined; the diameter and Laplace's law were used to calculate the bursting wall tension (BWT). The mean BWT in group 1 was 30.73 dyn. 10(3)/cm. In the multivariate analysis, adhesions to the anastomotic line were found to exert the greatest influence on the BWT (p = 0.005). The mean BWT of the anastomoses with adhesions affecting 100% of the circumference was greater than when at least part of the latter remained free (p = 0.006). In group 2 the BWT was 55.92 dyn. 10(3)/cm, i.e., greater than in group 1 overall (p = 0.005) and similar to those anastomoses in that group completely covered by adhesions (p = 0.017). Mean BWT in group 3 was 14.62 dyn. 10(3)/cm, i.e., lower than in either group 1 or 2 (p = 0.009 and 0.000, respectively). No differences were seen when comparing with group 1 segments in which the anastomotic line was not entirely covered. Adhesions to the anastomotic line exert a beneficial effect on colonic anastomotic resistance 4 days after surgery. Adhesion formation should therefore not be interfered with. An omentoplasty secures 100% coverage of the anastomotic line, and should thus be considered when performing high-risk colonic anastomoses.
Anastomosis, Surgical↗
[The relation of the adhesion phenomenon and the experimental resistance of colonic anastomoses. The effect of epiploplasty].
INTRODUCTION: We made an experimental study of the influence of the peritoneal adherence process on the strength of colic anastomosis. METHOD: 60 rats, in three groups of 20. Group I, colic anastomosis; Group II, colic anastomosis with epipoplasty; Group III, colic anastomosis covered with plastic material. They were slaughtered on the fourth post-operative day and we assessed the adherence parameters, removing the segment with anastomosis and measuring its breakage strength. Laplace's Law was applied to calculate Wall Breakage Stress (WBS). RESULTS: Group I: The statistically most significant influence on WBS was that of adherences to the anastomotic line (p = 0.005). WBS measured in anastomosis with adherence on 100% of the circumference was greater than in those where some part remained to be covered (p = 0.006). Group II: mean WBS was higher than in Group I as a whole (p = 0.005) and similar to that of the anastomosis in this group 100% covered by adherences (p = 0.017). Group III: mean WBS was lower than that of Group I (p = 0.009) and Group II (p = 0.000). CONCLUSIONS: The beneficial effect was demonstrated of adherences to the anastomotic line on the strength of colic anastomosis so that this process should not, wherever possible, be obstructed. During an epiploplasty, 100% coverage must be ensured: this technique must therefore be considered to belong to the group of high-risk colic anastomoses.
Anastomosis, Surgical↗