Biomedical subjects

Dalibor Antolovic

Publications and source records attributed to Dalibor Antolovic.

11 recordsLinked to original sources

PubMed2007

Detection of disseminated tumor cells in liver biopsies of colorectal cancer patients is not associated with a worse prognosis.

BACKGROUND: Liver metastases occur frequently in colorectal cancer and are probably caused by disseminated tumor cells having been trapped in the liver. The prognostic significance of hematogenous tumor cell dissemination has already been demonstrated for blood and bone marrow of patients with colorectal cancer. The aim of this study was to investigate the frequency and prognostic significance of disseminated tumor cells in liver biopsies of colorectal cancer patients. METHODS: Liver biopsies from 100 patients with UICC stage I-III colorectal cancer were taken prospectively during resection of the primary tumor. Liver biopsies obtained from 16 patients with benign gastrointestinal diseases served as negative controls. Liver samples from seven patients with liver cirrhosis were additionally taken. Liver biopsies were examined using a reverse transcriptase (RT)-PCR assay to amplify cytokeratin (CK) 20 transcripts. The median follow-up of the patients was 55 months. RESULTS: Disseminated tumor cells were detected in liver samples of 10/100 (10%) patients with UICC stage I-III colorectal cancer. Liver specimens from all seven patients with liver cirrhosis were CK 20-positive, whereas 16 patients with other benign gastrointestinal diseases were all CK 20-negative. There was no correlation between tumor cell detection in liver biopsies and survival of the patients. The only significant prognostic factor on uni- and multivariate analysis was the UICC stage. CONCLUSIONS: This study demonstrates that detection of disseminated tumor cells in liver samples from patients with UICC stage I-III colorectal cancer has no prognostic influence. UICC classification was the strongest prognostic factor in this patient series.

Aged↗

PubMed2006

Preoperative bowel preparation: surgical standard or past?

BACKGROUND: Preoperative bowel preparation is still routinely used prior to colorectal surgery. This concept is based on traditional and personal empiricism and usually not evidence based. The objective of the present review was to reassess this dogma against the background of the highest level of evidence published thus far. METHODS: The Medline database was searched using the search terms 'preoperative', 'bowel' and 'preparation' limited to 'randomized controlled trials' and 'meta-analyses'. Ten randomised controlled trials and seven meta-analyses comparing orthograde bowel cleansing to no preoperative bowel preparation were considered for rates of anastomotic leakages, surgical infections and other types of complications, reoperations and mortality. RESULTS: All the most recent meta-analyses showed a significant increase of anastomotic dehiscences in patients with preoperative orthograde bowel cleansing. Additionally, a trend towards higher rates of surgical infectious complications and re-operations was revealed. Mortality remained unchanged by preoperative orthograde bowel cleansing. CONCLUSION: Routine preoperative orthograde bowel cleansing is no longer justified prior to colorectal surgery in general due to increased risk of anastomotic leakages. Further investigations should focus on different types of bowel preparation in situations where preoperative bowel preparation still may have a role such as total mesorectal resection with low anastomosis and protective ileostomy.

Cathartics↗

PubMed2006

Totally laparoscopic versus conventional ileoanal pouch procedure--design of a single-centre, expertise based randomised controlled trial to compare the laparoscopic and conventional surgical approach in patients undergoing primary elective restorative proctocolectomy--LapConPouch-Trial.

BACKGROUND: Restorative proctocolectomy is increasingly being performed minimal invasively but a totally laparoscopic technique has not yet been compared to the standard open technique in a randomized study. METHODS/DESIGN: This is a two armed, single centre, expertise based, preoperatively randomized, patient blinded study. It is designed as a two-group parallel superiority study. Power calculation revealed 80 patients per group in order to recruit the 65 patients to be analysed for the primary endpoint. The primary objective is to investigate intra-operative blood loss and the need for blood transfusions. We hypothesise that intra-operative blood loss and the need for peri-operative blood transfusions are significantly higher in the conventional group. Additionally a set of surgical and non-surgical parameters related to the operation will be analysed as secondary objectives. These will include operative time, complications, postoperative pain, lung function, postoperative length of hospital stay, a cosmetic score and pre-and postoperative quality of life. DISCUSSION: The trial will answer the question whether there is indeed an advantage in the laparoscopic group in regard to blood loss and the need for blood transfusions. Moreover, it will generate data on the safety and potential advantages and disadvantages of the minimally invasive approach.

Adenomatous Polyposis Coli↗

PubMed2006

Effective antitumoral immune responses are not induced by cytosine deaminase suicide gene transfer in a syngeneic rat pancreatic carcinoma model.

BACKGROUND: Experimental gene transfer can make tumors more immunogenic, leading to local regression and inducing immunological memory sufficient to permit resistance to a tumor rechallenge. However, this rarely had any significant impact on large established tumors. METHODS: To analyze potential immunological effects, we used weakly immunogenic pancreatic carcinomas in syngeneic, immunocompetent Lewis rats and performed in situ adenoviral mediated cytosine deaminase (CD) gene transfer followed by administration of the prodrug, 5-fluorocytosine (5FC). In order to reflect the clinical situation, such treated tumors were surgically resected and animals were rechallenged with parental DSL6A pancreatic tumor cells. Tumor growth and cytotoxic activity of immune cells were determined. RESULTS: CD/5FC treatment of the DSL6A cells revealed significant induction of apoptosis in vitro and slowed down tumor progression in syngeneic hosts. Furthermore, we observed neither significant change in tumor growth nor protective immunity in the rechallenged animals. Analysis of T lymphocytes showed no specific cytotoxic activity against DSL6A cells. There was only a trend towards a minor NK cell activation. CONCLUSIONS: Albeit the present study failed to induce protective antitumor immunity, the initial finding of reduced tumor growth argues for the development of multimodal therapeutic options to overcome negative impacts of advanced malignant disease or chemotherapy-related anergy and immunosuppression.

Adenoviridae↗

PubMed2006

Prognostic impact of hematogenous tumor cell dissemination in patients with stage II colorectal cancer.

Adjuvant chemotherapy is not routinely recommended in patients with colorectal cancer stage UICC II. Some of these patients, however, develop recurrent disease. Therefore, valid prognostic criteria are needed to identify high-risk patients who might benefit from adjuvant therapy. Disseminated tumor cells, detected in blood and bone marrow, may prove to be a valid marker, however, the prognostic relevance of these cells remains debated. In our study, we examined the prognostic significance of disseminated tumor cells in blood and bone marrow of patients with stage II colorectal cancer. Ninety patients with potentially curative (R0) resection of colorectal cancer stage II were prospectively enrolled into the study. Bone marrow and blood samples were examined for disseminated tumor cells by CK 20 RT-PCR. Patient, tumor and treatment factors were analyzed as prognostic factors. Multivariate analysis confirmed tumor cell detection in blood (hazard ratio 2.1, p = 0.03) and T-category (hazard ratio 2.2, p = 0.02) to be independent prognostic factors for relapse-free survival. Tumor cell detection in postoperative blood samples (hazard ratio 7.7, p < 0.001) and number of removed lymph nodes (hazard ratio 6.4, p < 0.001) were independent prognostic factors for disease-specific survival. Detection of circulating tumor cells in blood samples of patients with stage II colorectal cancer identifies patients with poor outcome. This finding should be confirmed by further studies and could then be used as a basis for conducting a randomized trial evaluating the effect of adjuvant chemotherapy in stage II patients.

Aged↗

PubMed2006

Increased detection rate and potential prognostic impact of disseminated tumor cells in patients undergoing endorectal ultrasound for rectal cancer.

BACKGROUND: Hematogenous tumor-cell dissemination during diagnostic and therapeutic procedures in patients with colorectal cancer has been demonstrated. OBJECTIVE: The aim of this study was to investigate the extent of disseminated tumor cells in blood samples of rectal cancer patients after endorectal ultrasound and to determine its prognostic relevance. MATERIALS AND METHODS: Peripheral venous blood samples from 45 patients with rectal cancer were taken before and after endorectal ultrasound. Blood samples were examined using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to amplify cytokeratin 20 transcripts. Overall survival of the patients was calculated by the Kaplan-Meier method. RESULTS: Disseminated tumor cells were detected in peripheral blood samples of 17 of 45 (38%) patients before and after endorectal ultrasound. Circulating tumor cells were found in 11 of 45 (24%) patients only after endorectal ultrasound (p=0.006). There was a clear trend toward a worse prognosis in patients with tumor cells in blood samples after endorectal ultrasound, but this difference was not statistically significant. CONCLUSION: This study demonstrates significantly increased hematogenous tumor-cell dissemination after endorectal ultrasound in rectal cancer patients. Patients with tumor cells in blood samples after endorectal ultrasound tend to have a worse prognosis. The potential prognostic impact of this finding is presently unclear and has to be further validated in larger clinical trials.

Endoscopy, Gastrointestinal↗

PubMed2006

Tumor infiltrating T lymphocytes in colorectal cancer: Tumor-selective activation and cytotoxic activity in situ.

OBJECTIVE: To examine whether tumor-selective infiltration, activation, and cytotoxic activity of tumor infiltrating T lymphocytes (TIL) can be demonstrated in situ in colorectal cancer samples. SUMMARY BACKGROUND DATA: Recent studies indicated a correlation between the presence of TIL and an improved prognosis in colorectal cancer. However, tumor-selective activation and cytotoxic activity of CD8 TIL in situ in colorectal cancer patients have not yet been examined. METHODS: Tumor samples from 49 patients and corresponding normal mucosa samples from 23 patients with colorectal cancer (UICC stages II-IV) were examined for TIL. Two-color fluorescence immunohistochemistry and multicolor flowcytometric (FACS) analysis were used for quantification of CD8 T cells and measurement of their activation status (CD69-expression) and cytotoxic activity (CD107a-expression) in situ. Presence of tumor antigen-reactive T cells in tumor, blood, and bone marrow was evaluated by IFN-gamma Elispot analysis. RESULTS: While absolute numbers of CD8 T cells were similar, CD4 T helper cells were significantly increased in tumor tissue compared with normal mucosa. There was a significantly higher proportion of activated and cytotoxically active CD8 TIL in colorectal cancer compared with normal mucosa. Increased activation, cytotoxic activity, and functional reactivity of TIL were correlated with the presence of functional tumor antigen-reactive T cells in the blood and bone marrow. The proportion of activated TIL decreased significantly with higher tumor stage. CONCLUSIONS: Tumor-selective activation and cytotoxic activity of CD8 TIL and tumor-selective migration of CD4 T helper cells were demonstrated in colorectal cancer for the first time. Our data support the immunogenicity of colorectal cancer and suggest clinical significance of tumor-specific immune responses.

Adenocarcinoma↗

PubMed2005

Short description of an alternative simplified method for screening recombinant clones within the "AdEasy-System" by Duplex-PCR.

BACKGROUND: Recombinant adenoviral vectors are highly efficient for in vitro and in vivo gene delivery. They can easily be produced in large numbers, transduce a wide variety of cell types and generate high levels of transgene expression. The AdEasy system is a widely used system for generating recombinant adenoviral vectors, which are created with a minimum of enzymatic manipulations and by employing homologous recombination in E. coli. In this paper we describe an alternative simplified method for screening recombinant DNA within the AdEasy system. This Duplex-PCR-method is independent of the transgene or insert and can be used for the complete AdEasy system. It is characterized by a simple standard protocol and the results can be obtained within a few hours. The PCR is run with two different primer sets. The primers KanaFor and KanaRev hybridizise with the Kanamycin resistence gene and AdFor and AdRev detect the adenoviral backbone. In case of recombinant clones, two diagnostic fragments with a size of 384 bp and 768 bp are generated. RESULTS: The practicability of this method was verified with three different transgenes: Cytosin Deaminase (AdCD), p53 (Adp53) and Granulocyte Macrophage Colony Stimulating Factor (AdGM-CSF). Recombinant clones are indicated by two diagnostic fragments and are then suitable for further processing. CONCLUSION: In summary, the presented protocol allows fast detection of recombinants with an easy technique by minimizing the amount of necessary steps for generating a recombinant adenovirus. This method is time sparing and cost-effective.

Adenoviridae↗

PubMed2005

Is the lateral lymph node compartment relevant?

Lateral pelvic lymphadenectomy is routinely performed in advanced lower rectal cancers by Japanese surgeons, whereas in the western world it has not progressed to a frequently performed technique. Claimed benefit for this extensive surgery is an improved locoregional control; on the other hand, low positive lateral lymph node yields, questionable prognostic significance, and high morbidity (urinary and sexual dysfunction) are main reasons against this procedure. Clinical results published on lateral lymphadenectomy in the literature are conflicting. Due to major improvements in local control and survival of rectal cancer patients mainly based on preoperative radiotherapy and total mesorectal excision (TME), only a few patients may profit from lateral lymph node dissection. This article gives an overview of the current status and the clinical relevance of the lateral lymph node compartment in rectal cancer surgery.

Humans↗

PubMed2005

Detection of hematogenous tumor cell dissemination predicts tumor relapse in patients undergoing surgical resection of colorectal liver metastases.

OBJECTIVE: To examine the prognostic significance of disseminated tumor cells in blood and bone marrow of patients undergoing surgical resection of colorectal liver metastases. SUMMARY BACKGROUND DATA: Despite curative hepatic resection of colorectal liver metastases, a high percentage of patients develop tumor recurrence. These recurrences probably originate from disseminated tumor cells released into the circulation before or during surgery. METHODS: Thirty-seven patients with potentially curative (R0) resection of colorectal liver metastases were prospectively enrolled into the study. Preoperative bone marrow samples and preoperative, intraoperative, and postoperative blood samples were examined for disseminated tumor cells by CK20 RT-PCR. RESULTS: Tumor cells were detected in preoperative blood samples in 11 of 37 (30%) patients, in intraoperative blood samples in 17 of 37 (46%) patients, and in postoperative blood samples in 8 of 37 (22%) patients. Four of 25 (16%) patients tested positive for disseminated tumor cells in bone marrow samples. Median follow-up time for all patients was 38 months (range, 10-63 months). Multivariate analysis confirmed tumor cell detection in intraoperative blood (P = 0.009) and in bone marrow samples (P = 0.013) to be independent prognostic factors of tumor relapse. CONCLUSIONS: This is the first study demonstrating that detection of hematogenous tumor cell dissemination during hepatic resection of colorectal cancer metastases predicts tumor relapse. Detection of disseminated tumor cells may help to individualize adjuvant therapy for patients with colorectal liver metastases and to develop surgical strategies to prevent intraoperative hematogenous tumor cell shedding.

Aged↗

PubMed2004

The effect of adenovirus expressing wild-type p53 on 5-fluorouracil chemosensitivity is related to p53 status in pancreatic cancer cell lines.

AIM: There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU). Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53 gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status. METHODS: Human pancreatic cancer cell lines Capan-1(p53mut), Capan-2(p53wt), FAMPAC(p53mut), PANC1(p53mut), and rat pancreatic cancer cell lines AS(p53wt) and DSL6A(p53null) were used for in vitro studies. Following infection with different ratios of Ad-p53-particles (MOI) in combination with 5-FU, proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining). In addition, DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivo studies. Tumor size, apoptosis (TUNEL) and survival were determined. RESULTS: Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing wt-p53. In vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus 5-FU. Both in vitro and in vivo analyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU. CONCLUSION: Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 function. These findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.

Adenoviridae↗