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Biomedical subjects

D Kardamakis

Publications and source records attributed to D Kardamakis.

At least 19 recordsLinked to original sources
PubMed2001

X-rays modulate extracellular matrix in vivo.

X-rays have an antiangiogenic effect in the chicken embryo chorioallantoic membrane (CAM) model of in vivo angiogenesis. Our study demonstrates that X-rays induce an early apoptosis of CAM cells, modulate the synthesis and deposition of extracellular matrix (ECM) proteins involved in regulating angiogenesis and affect angiogenesis induced by tumour cells implanted onto the CAM. Apoptosis was evident within 1-2 hr, but not later than 6 hr after irradiation. Fibronectin, laminin, collagen type I, integrin alpha(v)beta3 and MMP-2 protein amounts were all decreased 6 hr after irradiation. In contrast, collagen type IV, which is restricted to basement membrane, was not affected by irradiation of the CAM. There was a similar decrease of gene expression for fibronectin, laminin, collagen type I and MMP-2, 6 hr after irradiation. The levels of mRNA for integrin alpha(v)beta3 and collagen type IV were unaffected up to 24 hr after irradiation. The decrease in both protein and mRNA levels was reversed at later time points and 48 hr after irradiation, there was a significant increase in the expression of all the genes studied. When C6 glioma tumour cells were implanted on irradiated CAMs, there was a significant increase in the angiogenesis induced by tumour cells, compared to that in non-irradiated CAMs. Therefore, although X-rays have an initial inhibitory effect on angiogenesis, their action on the ECM enhances new vessel formation induced by glioma cells implanted on the tissue.

Animals↗
PubMed2001

Randomized comparison of early versus late hyperfractionated thoracic irradiation concurrently with chemotherapy in limited disease small-cell lung cancer: a randomized phase II study of the Hellenic Cooperative Oncology Group (HeCOG).

BACKGROUND: Concurrent platinum etoposide chemotherapy given in combination with hyperfractionated thoracic radiation therapy (HTRT) in limited disease (LD) small cell lung cancer (SCLC) is associated with a high response rate and significant prolongation of survival. Given these results, the Hellenic Cooperative Oncology Group (HeCOG) performed a multicenter randomized phase II study in patients with LD SCLC to evaluate the timing of HTRT (early vs. late) when given concurrently with chemotherapy. PATIENTS AND METHODS: To be eligible for the study, patients were required to have histologically or cytologically proven LD SCLC, confined to one hemithorax and/or ipsilateral mediastinal or supraclavicular lymphnodes and absence of pleural effusion or controlateral supraclavicular lymphnode involvement. Moreover, patients had to have a good performance status and adequate haematological, liver and renal function. Patients with LD SCLC were randomized to receive HTRT either concurrently with the first (Group A) or with the fourth (Group B) cycle of chemotherapy. Chemotherapy consisted of carboplatin administered at an AUC of six given as an i.v. 1-hour-infusion immediately followed by etoposide at a dose of 100 mg/m2 i.v. as a two-hour infusion for three consecutive days every three weeks up to a total of six cycles. Prophylactic cranial irradiation was also given to patients achieving a complete response. RESULTS: 42 and 39 patients, were eligible for efficacy evaluation in group A and B respectively. The overall response rate was 76% in group A and 92.5% in group B (P = 0.07) with a complete response rate of 40.5% and 56.5%, respectively. After a median follow-up of 35 months, time to progression was 9.5 months in group A and 10.5 in group B (NS) while overall median survival was 17.5 and 17 months respectively (NS). The 2-year survival was 36% in group A and 29% in group B (NS) and the 3-year survival 22% and 13%, respectively (NS). The distant relapse rate was 38% in group A and 61% in group B (P = 0.046). Severe grade 3 4 anemia was recorded in 19% of group A and 12.5% of group B (NS), while severe leucopenia was recorded in 35.5% and 20.5% (P = 0.09) and neutropenic fever in 5% and 2.5% (NS), respectively. Severe thrombocytopenia did not differ significantly between the two treatment groups being 21.5% and 23%, respectively. Severe grade 2-3 esophageal toxicity was 19% in group A and 23% in group B (NS), while grade 3 lung toxicity was 5% and 7.5% (NS), respectively. No toxicity-related deaths were recorded. CONCLUSION: Concurrent administration of HTRT with carboplatin etoposide is associated with a high response and survival rate. Although a trend for higher response rate was recorded in the group of patients who received late HTRT, the overall median, 2-year and 3-year survival rates did not differ significantly between the two treatment groups. The toxicity of this promising therapeutic approach was acceptable. Comparative phase III studies with an adequate number of patients are recommended in order to answer this question.

Adult↗
PubMed2001

Impact of cancer on primary caregivers of patients receiving radiation therapy.

The main objective of this study was to assess the consequences of caregiving on primary caregivers of Greek cancer patients receiving radiotherapy. Sixty-five caregivers participated in the study and data were collected through structured interviews. Our results pointed to a lack of association concerning extent of patients' disease, treatment schedule, performance status or awareness of diagnosis. However, female caregivers with low qualifications, partners, and those living with the patient were more likely to report heightened symptoms of anxiety and depression, severe impact of caregiving on their lives, poor health and low quality of life. In addition, it was shown through multivariate analyses that psychological distress was the sole predictor of overall health and global quality of life. In conclusion, Greek caregivers are to a great extent affected by the disease. Caring for significant others is essential to promoting quality of life for the family and the patient.

Adult↗
PubMed2001

bcl-2/bax ratio as a predictive marker for therapeutic response to radiotherapy in patients with rectal cancer.

Combined radiation therapy and chemotherapy are adjuvant treatments given after surgery to patients with rectal carcinoma. Because apoptosis seems to play a role in tumor response to radiotherapy, the current study investigates whether there is a correlation between the ratio of bcl-2 oncoprotein and bax expression in rectal adenocarcinoma and the clinical response to radiotherapy. Elective colectomy for primary rectal adenocarcinoma followed by adjuvant radiotherapy and chemotherapy was performed on 35 patients. Tumors were staged as B2 (n = 30) and C (n = 5), and were classified as radiation resistant (n = 19, group A) and radiation nonresistant (n = 16, group B). Immunohistochemical study, using the streptavidin-biotin complex technique and monoclonal antibody to bcl-2 and polyclonal antibody to bax protein was used on paraffin sections. Cases were considered positive if at least 5% of tumor cells displayed cytoplasmic staining for bcl-2 or bax. In each tumor, the bcl-2/bax ratio was calculated dividing the percentage of bcl-2-positive cells by the percentage of bax-positive cells. For statistical analysis, the Mann-Whitney rank sum test and Kruskal-Wallis analysis of variance test were used. Rectal tumors of group A displayed significantly greater bcl-2 immunoreactivity (40.2 +/- 4.2) compared with group B (20.2 +/- 3.8). In contrast, expression of bax protein was less in group A (30.3 +/- 3.3) compared with group B (41.3 +/- 2.3). The bcl-2/bax ratio was greater in group A (1.3 +/- 0.1) compared with group B (0.49 +/- 0.1), and was correlated with poor responsiveness to radiotherapy. The current study indicates that in patients with rectal carcinoma an elevated bcl-2/bax ratio in tissue specimens suggests increased tumor resistance to adjuvant radiotherapy. Thus, in such patients, the bcl-2/bax ratio may serve as a potential molecular marker for prediction of tumor prognosis.

Adenocarcinoma↗
PubMed1999

An integrated system for the production of field shaping devices in radiotherapy.

A system has been developed in our department that simplifies the production processes of field shaping devices in radiotherapy, integrating an image grabbing and processing facility at a radiotherapy simulator and an automated block cutter. The data acquisition subsystem captures images, processes and corrects them for pincushion distortions, creates a composite radiograph, records user defined contours of blocks and exports data to the block cutter controller. A robotic subsystem drives and controls the polystyrene cutting unit. The system has been experimentally evaluated. Errors in contour definition were found to be less than 1 mm for a broad range of gantry angles and not exceeding 1.5 mm for those gantry orientations that present maximum magnetic field related image intensifier distortion, while the automated block cutter is capable of cutting out contours in polystyrene with an accuracy comparable to that of commercially available systems. The system is expected to contribute to the overall improvement of radiotherapy processes, particularly in low budget radiotherapy departments, introducing improvements in accuracy and efficiency at minimum costs.

Cost Control↗
PubMed1997

Advanced non-small cell lung cancer chemotherapy: a randomized trial of two active regimens (MVP and PE).

The treatment of advanced or metastatic NSCLC remains a controversial issue and cisplatin-based combination chemotherapy is by far the most common treatment. Two of these cisplatin-based standard combinations, MVP and PE, were compared in this study in order to evaluate their response rates and survival times. Eighty-five previously untreated NSCLC patients were randomly selected to receive either MVP or PE and 72 of these patients were eligible for evaluation for response rate and survival. Response rates for MVP were: CR 11%, PR 35%, SD 19% and PD 35% and for PE: CR 0%, PR 26%, SD 22% and PD 52%. The median survival time was 9.7 months for MVP and 6.9 months for PE. Both schedules were well tolerated. The administration of MVP in advanced NSCLC resulted in superior response rates and survival times over those produced by PE.

Adult↗
PubMed1997

Management of non resectable malignant esophageal stricture and fistula.

OBJECTIVE: The palliation of dysphagia caused by esophageal carcinoma and other inoperable tumours obstructing the esophagus presents a challenge for the thoracic surgeon, in particularly when associated with fistula (F). In a prospective study over the last 5 years, we have evaluated the effectiveness of different approaches and types of prostheses to solve the above problem. METHOD: Thirty three patients (mean age: 63.5 years, range 42-76, M/F:24/9) with inoperable tumours obstructing the esophagus underwent intubation and/or palliative surgery according to the following protocol: (1) Preoperative esophagography; (2) endoscopy and biopsy; (3) dilatation and insertion of prosthesis usually under general anaesthesia; and (4) re-evaluation the following day, in 30 days and as required thereafter. Prosthesis used were: Atkinson 3, Wilson-Cook (plain) 12, Wilson-Cook (cuffed) 4, Strecker (metallic self-expandable) 13. The patients were divided in three groups according to the extension of the disease: group A (n = 19) plain malignant strictures, group B (n = 5) strictures with respiratory Fs, group C (n = 9) strictures with mediastinal or pleural Fs. RESULTS: All patients of group A had successful palliation irrespectively of prosthesis used and site of obstruction. One patient required two stents. There was no death and 50% survival at 6 months was 70%. In group B, a cuffed prosthesis successfully closed two bronchoesophageal Fs, while three patients underwent retrosternal bypass surgery. There was one death on the 26th postoperative day. In group C, one Strecker, two plain Wilson-Cook and two cuffed Wilson-Cook stents, although initially succeeded, in due course, failed to block the Fs in five patients who subsequently underwent bypass surgery with one death. With four patients both leak and dysphagia were significantly improved with the use of self-expandable stents therefore, not requiring surgery. Overall, there were two deaths but no failure in palliating dysphagia. Longer survival was 20 months. Patients with fistulae had poorer prognosis as compared to those suffering from plain malignant stricture (P = 0.01). CONCLUSIONS: Plain malignant inoperable oesophageal strictures can be successfully palliated with intubation. Complicated with fistula strictures, however, are difficult to manage and have a poor prognosis. Due to the fact that bypass surgery is associated with an increased mortality, it should be kept for those with late stent failures and fistula recurrences.

Adult↗
PubMed1996

A novel radiological approach for the experimental study of angiogenesis: angiography of the chick embryo and its chorioallantoic membrane.

We use a modification of the digital substraction angiography (DSA) technique to visualize the vascular system of the chorioallantoic membrane (CAM) of the developing chick embryo. After catheterization of the central vein of the CAM with a metallic needle and injection of contrast medium, angiography was performed at specified follow-up intervals (1-2.5 images per second) using the Philips DVI-S Angiography Unit. By applying the vascular casting technique we were able to visualize the vessels of the CAM and to study the existing complex vascular-anatomical relationships. Our results show that DSA demonstrates the development of the circulatory system of the chick embryo (heart and vessels) and the vessels of its CAM effectively. By applying for the first time interventional radiology techniques on the chick embryo system, it has been possible to study morphological changes of the vessels during angiogenesis in vivo. These results suggest that this technique can be a proven and valuable tool in the quantitative assessment of angiogenesis.

Allantois↗
PubMed1996

Primary hemangiosarcoma of the mediastinum.

A case of a 44-year-old female who had an intrathoracic mass that was found to be a hemangiosarcoma of the anterior mediastinum is reported. Radical surgical incision through a right anterior thoracotomy was performed, followed by post-operative radiotherapy. Since this is a rare tumor at this location, the clinical and radiological findings, the histopathological appearances and its therapeutic management are discussed. Radiologists, surgeons and oncologists should in the differential diagnosis of a mediastinal mass include that of a tumor of vascular origin, even if it is rare. Radical excision followed by post-operative radiotherapy, especially in cases where the tumor has been partially excised, is the treatment of choice.

Adult↗
PubMed1996

In vivo experimental evidence that the nitric oxide pathway is involved in the X-ray-induced antiangiogenicity.

We have investigated both the effects of X-rays on angiogenesis and the possible role of nitric oxide (NO) on the observed antiangiogenic effect of X-rays, using as an in vivo model the chick embryo chorioallantoic membrane (CAM). These effects were assessed both morphologically and biochemically, by measuring vascular density and collagenous protein biosynthesis, respectively, on days 9 and 14 of the chick embryo development. Vascular density and cytotoxicity of the CAM were also evaluated histologically. We have shown that X-rays have an antiangiogenic effect on the system used and that the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) promoted angiogenesis of the non-irradiated CAM and reversed the antiangiogenic effect of irradiation. D-NAME, which is an inactive enantiomer of L-NAME, showed no such effects. L-Arginine, which is the substrate for NO synthase, had a modest antiangiogenic effect on the non-irradiated CAM, no effect on the irradiated CAM and abolished the angiogenic effect of L-NAME on these CAM preparations. These results suggest that NO is involved in the antiangiogenic mechanism of X-rays and that pharmacological manipulation of NO firstly, may offer a better understanding of these mechanisms and, secondly, may also prove to be an alternative therapeutic approach for treating pathological conditions involving angiogenesis.

Animals↗
PubMed1988

Rate of incorporation of radiolabelled nucleosides does not necessarily reflect the metabolic state of cells in culture: effects of latent mycoplasma contamination.

In response to cell-free conditioned medium derived from the human bladder carcinoma line T24 (T24 SN), we found greatly reduced incorporation of tritiated thymidine and uridine ([3H]TdR, [3H]UR) by the human carcinoma lines UCHNCu (small-cell lung carcinoma) and LS174T (colon carcinoma). The effect was not due to an excess of nucleosides or cytokines known to be present in T24 SN. Cell-cycle distribution, increase in cell numbers, and de novo nucleoside synthesis in the indicator cells were only slightly altered. This was in contrast to the gross reduction in [3H]TdR/[3H]UR incorporation and seemed to indicate selective downregulation of pyrimidine-salvage pathways, despite ongoing polynucleotide synthesis. Spontaneous [3H]TdR uptake remained low for several passages in vitro but was readily restored by pharmacological inhibition of de novo pathways with 5-fluoro-deoxy-uridine (5-FUdR). This suggested a stable but reversible regulatory effect of T24 SN on the pyrimidine metabolism of the indicator cells. Further investigation showed degradation of [3H]TdR by a particle-bound activity in T24 SN. Mycoplasma contamination of T24 had not been detectable using standard cultural and staining methods, but became apparent when T24-cell lysates were hybridized with a recently described DNA probe (Goebel & Stanbridge, 1984). We conclude that latent mycoplasma contamination can stimulate changes in cellular pyrimidine metabolism. Our results provide an example for latent mycoplasma infection mimicking metabolic changes in cultured cells by direct interference of a microbial enzyme with the assay system. We describe a rapid and simple bioassay to detect and distinguish particle-associated and soluble phosphorylase activity by [3H]TdR degradation. It may be a useful screening assay for mycoplasma contamination in tissue culture.

Cell Line↗
PubMedDate not supplied

X-rays affect the expression of genes involved in angiogenesis.

BACKGROUND: We have previously shown, using the chicken embryo chorioallantoic membrane (CAM) model of in vivo angiogenesis, that X-rays act on the extracellular matrix and enhance normal and tumor-induced angiogenesis. In the present work, we studied the effect of X-rays on the gene expression of three proteins that are important regulators of angiogenesis: vascular endothelial growth factor (VEGF), heparin affin regulatory peptide (HARP) and inducible nitric oxide synthase (iNOS). MATERIALS AND METHODS: An area of 1 cm2 of the CAM, restricted by a plastic ring was irradiated at room temperature. The expression of the genes was studied using RT-PCR and the amounts of the mRNAs were quantified using image analysis of the corresponding agarose gels of the RT-PCR products. RESULTS: VEGF mRNA was decreased 6 h after irradiation. However, at later time points, VEGF expression was significantly increased compared with the nonirradiated tissue. Similarly, X-rays down-regulated both HARP and iNOS expression 6 h after irradiation and the effect was reversed at later time points, similarly to the effect of X-rays on VEGF. CONCLUSION: These data support the notion that X-rays increase the expression of genes that favor angiogenesis.

Animals↗