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Biomedical subjects

M Tzivras

Publications and source records attributed to M Tzivras.

At least 19 recordsLinked to original sources
PubMed2004

Effects of hemodialysis on serum lipids and phospholipids of end-stage renal failure patients.

Patients with chronic renal failure undergoing periodic maintenance hemodialysis frequently present dyslipoproteinaemia which has been linked to the sharply increased risk of cardiovascular disease in these subjects. Reported defects on lipoprotein-related enzyme activities suggest a possible influence of hemodialysis not just to plasma lipid and lipoprotein levels but also to the composition of cell membranes. In this study, it was investigated whether the reported lipid abnormalities are accompanied by changes in serum phospholipids levels. Blood samples were obtained from 140 patients undergoing maintenance hemodialysis treatment and 122 normolipidemic healthy controls and analyzed for total serum phospholipids and their individual subclasses, as well as for total cholesterol and triglycerides, HDL-cholesterol and its subclasses. A significant decrease was observed in serum HDL cholesterol levels (p < 0.001) and its subclasses, HDL2-cholesterol (p < 0.01) and HDL3-cholesterol (p < 0.01) in patients when compared with healthy controls. A critical increase in the serum triglyceride content (p < 0.001) of patients was also observed. In addition, the serum levels of sphingomyelin (p < 0.01) and diphosphatidylglycerol (p < 0.001) were increased in the patient group, while the levels of phosphatidylcholine (p < 0.01) and phosphatidylinositol (p < 0.01) were significantly decreased in the patient group compared to healthy controls. In conclusion, this work clearly demonstrates that hemodialysis treatment contributes significantly to the dyslipidemic profile of end-stage renal failure patients by altering serum lipoprotein and phospholipids concentrations.

Adult↗
PubMed2003

Computer-aided tumor detection in endoscopic video using color wavelet features.

We present an approach to the detection of tumors in colonoscopic video. It is based on a new color feature extraction scheme to represent the different regions in the frame sequence. This scheme is built on the wavelet decomposition. The features named as color wavelet covariance (CWC) are based on the covariances of second-order textural measures and an optimum subset of them is proposed after the application of a selection algorithm. The proposed approach is supported by a linear discriminant analysis (LDA) procedure for the characterization of the image regions along the video frames. The whole methodology has been applied on real data sets of color colonoscopic videos. The performance in the detection of abnormal colonic regions corresponding to adenomatous polyps has been estimated high, reaching 97% specificity and 90% sensitivity.

Adenomatous Polyps↗
PubMed2001

Jejunogastric intussusception presented with hematemesis: a case presentation and review of the literature.

BACKGROUND: Jejunogastric intussusception (JGI) is a rare but potentially very serious complication of gastrectomy or gastrojejunostomy. To avoid mortality early diagnosis and prompt surgical intervention is mandatory. CASE PRESENTATION: A young man presented with epigastric pain and bilous vomiting followed by hematemesis,10 years after vagotomy and gastrojejunostomy for a bleeding duodenal ulcer. Emergency endoscopy showed JGI and the CT scan of the abdomen was compatible with this diagnosis. At laparotomy a retrograde type II, JGI was confirmed and managed by reduction of JGI without intestinal resection. Postoperative recovery was uneventful. CONCLUSIONS: JGI is a rare condition and less than 200 cases have been published since its first description in 1914. The clinical picture is almost diagnostic. Endoscopy performed by someone familiar with this rare entity is certainly diagnostic and CT-Scan of the abdomen could also help. There is no medical treatment for acute JGI and the correct treatment is surgical intervention as soon as possible.

Adult↗
PubMed2000

Expression of HLA-DR, costimulatory molecules B7-1, B7-2, intercellular adhesion molecule-1 (ICAM-1) and Fas ligand (FasL) on gastric epithelial cells in Helicobacter pylori gastritis; influence of H. pylori eradication.

There is evidence that Helicobacter pylori infection up-regulates the expression of HLA class II molecules by gastric epithelial cells (GEC). In this study we evaluated whether GEC are capable of expression of costimulatory molecules in H. pylori gastritis. The expression of FasL by GEC, before and after eradication of H. pylori, was also studied. Thirty patients (23 men) aged 27-81 years (53.67 +/- 13.99 years (mean +/- s.d.)) with dyspepsia were studied. Upper gastrointestinal endoscopy was performed and six biopsies were obtained (antrum, n = 3; corpus, n = 3) for Campylobacter-Like Organisms (CLO) test and histology; 23 (16 men) were H. pylori+ and seven (all men) were H. pylori- by both methods and served as controls. Helicobacter pylori eradication therapy was given to H. pylori+ patients and all patients were re-endoscoped after 116 +/- 9 days. Formalin-fixed paraffin-embedded tissue sections were stained by the ABC immunoalkaline phosphatase method. In H. pylori gastritis HLA-DR was expressed and correlated with disease activity (P < 0.01). No HLA-DR was observed in controls. In H. pylori-eradicated patients significant decrease of HLA-DR was found (antrum, P < 0. 001). ICAM-1 was expressed by GEC in 80% of H. pylori+ patients; ICAM-1 expression did not correlate with gastritis parameters and decreased significantly after eradication (antrum, P < 0.01). B7-1 and B7-2 were expressed on H. pylori+ samples and their expression decreased after eradication, albeit not significantly. Weak epithelial expression of both B7 molecules was observed in all the controls. FasL was steadily expressed by GEC in both H. pylori+ and H. pylori- patients and remained almost unchanged after eradication. These findings suggest that GEC may acquire antigen-presenting cell properties in H. pylori infection through de novo expression of HLA-DR and costimulatory molecules. This seems to be attenuated after eradication and resolution of mucosal inflammation. The same cells exhibit the capacity to control the inflammatory process, probably by inducing apoptotic cell death to Fas-bearing infiltrating lymphocytes.

Adult↗
PubMed2000

Rapid urease test is less sensitive than histology in diagnosing Helicobacter pylori infection in patients with non-variceal upper gastrointestinal bleeding.

BACKGROUND AND AIMS: The validity of the rapid urease (CLO) test to diagnose Helicobacter pylori infection in patients with bleeding ulcers has been questioned. The aim of this paper is to evaluate the validity of the CLO test in comparison with histology in diagnosing H. pylori infection in patients with acute upper gastrointestinal bleeding (UGB), irrespective of non-steroidal anti-inflammatory drug (NSAID) use. METHODS: Upper gastrointestinal endoscopy was performed within 24 h of admission for all patients with UGB admitted to the Department of Pathophysiology, Medical School, Athens, for a period of 12 months. Patients with variceal bleeding, previous gastric operation, recent treatment with proton pump inhibitors (< 2 months) and those with a history of H. pylori eradication therapy were excluded from the study. At least four biopsies (two from the antrum and two from the body) were obtained for the CLO test and histology (modified Giemsa). RESULTS: Seventy-two consecutive patients (aged 18-90 years, 51 men, 21 women) were included. Forty-six patients (64%) used NSAID. Thirty-two patients (44%) were found to be positive for H. pylori infection by the CLO test, while 44 patients (61%) were found to be positive on histology (P<0.045, 95% CI, 0.004-0.331). The sensitivity and specificity of the CLO test were 68 and 93% respectively; positive and negative predictive values were 94 and 65%, respectively. The age of the patient and visible blood in the stomach did not influence results of either the CLO or histology. CONCLUSIONS: The CLO test, performed within 24 h of hospital admission in patients with UGB, irrespective of NSAID use, is unreliable for the detection of H. pylori infection. The age of the patient and the presence of blood in the stomach do not seem to influence these results.

Adolescent↗
PubMed2000

The CLO test is unreliable in diagnosing H. pylori infection in post-surgical stomach; is there any role of H. pylori in peptic ulcer recurrence?

AIM: To evaluate the validity of the CLO test in detecting Helicobacter pylori in patients with gastric operation and to investigate the relationship of H. pylori with peptic ulcer recurrence in these patients. METHODS: In this prospective study, 110 consecutive patients, the majority of whom had undergone gastric operation for benign disease (n = 102), were included. Eighty patients (62 males), aged 38-87 years, had had a gastrectomy (10 Billroth I, 70 Billroth II), and 30 patients (27 males), aged 36-73 years, had had a vagotomy (13 vagotomy plus gastroenterostomy, 17 vagotomy plus pyloroplasty). H. pylori was sought on multiple biopsy specimens, using CLO test and histology (modified Giemsa stain). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the CLO test were estimated using histology as 'gold standard'. RESULTS: Overall, 21 gastrectomy patients (26%) were H. pylori-positive by CLO and 25 (31 %) were H. pylori-positive by histology. The estimated sensitivity, specificity, PPV and NPV of the CLO test, using histology as 'gold standard', were 68%, 91%, 77% and 86%, respectively. The CLO test was positive in 67% of vagotomy patients (20 of 30), while 50% (15 of 30) were H. pylori-positive by histology. The estimated sensitivity, specificity, PPV and NPV of the CLO test were 87%, 53%, 65% and 80%, respectively. H. pylori prevalence by histology was 50% in patients with vagotomy and 31% in those with gastrectomy (P = 0.0787). Recurrent ulcers were observed in 8/30 patients (27%) after vagotomy and in 10/72 patients (14%) after gastrectomy. Recurrent ulcer was documented in 6/15 H. pylori-positive patients with vagotomy (40%), and in one of 25 H. pylori-positive patients with gastrectomy (4%). This difference was significant (Fisher's exact test, P = 0.007, relative risk 5.091, 95% CI 0.819-31.64). CONCLUSION: The CLO test seems to be unreliable in diagnosing H. pylori in post-surgical stomach. The H. pylori prevalence is higher, although not significantly, in vagotomized patients compared with gastrectomized patients, and in this group is closely related to the presence of recurrent ulcer. So, at least in this group of patients, it is strongly recommended to look for and eradicate H. pylori.

Adult↗
PubMed2000

Neural network application in the discrimination of benign from malignant gastric cells.

OBJECTIVE: To investigate the potential value of morphometry and neural networks for the discrimination of benign from malignant gastric lesions. STUDY DESIGN: One thousand cells from 19 cases of cancer, 19 cases of gastritis and 56 cases of ulcer were selected as a training set, and an additional 4,000 cells from the same cases of cancer, gastritis and ulcer were used as a test set. Images of routinely processed gastric smears stained by the Papanicolaou technique were analyzed by a custom-made image analysis system. RESULTS: Application of the neural network gave correct classification in 96% of benign cells and 89% of malignant cells. CONCLUSION: The results indicate that the use of neural networks and image morphometry may offer useful information concerning the potential of malignancy in gastric cells.

Cytodiagnosis↗
PubMed2000

Ranitidine versus ranitidine plus octreotide in the treatment of acute non-variceal upper gastrointestinal bleeding: a prospective randomised study.

AIM: To compare the efficacy of ranitidine with that of ranitidine plus octreotide in the treatment of non-variceal upper gastrointestinal (UGI) bleeding. DESIGN: Prospective, randomised, open study. PATIENTS AND METHODS: Upper GI endoscopy was carried out during the first 24 hours in all patients with UGI bleeding who had been admitted within a period of 18 months. Patients with variceal bleeding, and those who had undergone any type of gastric operation, were excluded. Eighty-four patients (58 men and 26 women) aged 21-92 years (mean age: 61.2 +/- 15.0 SD) were included. Patients were randomised to receive ranitidine 50 mg tid intravenously alone (Group A: 44 patients, 29 men), or in combination with octreotide 100 micrograms tid subcutaneously, the second drug given for three days only (Group B: 40 patients, 29 men). The study end-points were discharge without operation, emergency surgical intervention or death. The number of blood units given and the days of hospitalization were also recorded. RESULTS: Aspirin and non-aspirin NSAID use before bleeding was reported by 16/44 (36%) patients in Group A and by 19/40 (47.5%) patients in Group B (p = 0.38, OR = 0.63, 95% CI = 0.26-1.51). The endoscopically detected pathology and bleeding stigmata did not differ between the groups (p = 0.86, p = 0.64, OR = 0.78, 95% CI = 0.3-1.99, respectively). Mean use of blood units (p = 0.16) and days of hospitalization (p = 0.25) did not differ. Three patients in Group A (6.8%) and three in Group B (7.5%) required surgical intervention (p = 1.0, OR = 1.1, 95% CI = 0.21-5.84). CONCLUSION: Ranitidine plus subcutaneous octreotide is not superior to ranitidine alone in the management of patients with acute non-variceal UGI bleeding.

Adult↗
PubMed1999

Clinical significance of plasma HDL subfractions (HDL2, HDL3) in patients with peripheral arterial disease (PAD) in the Greek population.

OBJECTIVE: In this study the major high density lipoprotein (HDL) subfractions (HDL2, HDL3) were examined, in angiographically selected patients with peripheral arterial disease (PAD). RESULTS: Patients with PAD have significantly high triglyceride levels. HDL2 and HDL3 levels were found significantly reduced in patients with PAD. Also, the ratio HDL2-C/HDL3-C was significantly reduced in patients with PAD. CONCLUSIONS: The aim of the present study is to provide additional support to the hypothesis that the determination of HDL subfractions could be useful to elucidate possible mechanism(s) for a better assessment of the risk profile for PAD.

Aged↗
PubMed1998

Clostridium difficile colitis associated with a 'triple' regimen, containing clarithromycin and metronidazole, to eradicate Helicobacter pylori.

We describe a 54-year-old man with Helicobacter pylori (+) duodenal ulcer who developed Clostridium difficile associated colitis, 5 days after commencing a 'triple' regimen consisting of omeprazole 20 mg b.d., metronidazole 500 mg b.d. and clarithromycin 500 mg b.d., to eradicate H. pylori. Despite the fact that oral metronidazole did not prevent the disease, the patient did well after treatment with oral metronidazole plus a yeast preparation (Saccharomyces bulardii). No relapse occurred.

Anti-Ulcer Agents↗
PubMed1998

Combined epirubicin, 5-fluorouracil and folinic acid vs no treatment for patients with advanced pancreatic cancer: a prospective comparative study.

The combination of 5-fluorouracil (5-FU) and folinic acid (FA) has demonstrated activity in most gastrointestinal tumors. The addition of epirubicin (EPI) may increase the efficacy of the combination for cancers of the upper gastrointestinal tract, such as advanced pancreatic cancer. We examined two groups of patients, explaining the potential benefits and limitations of therapy, and those patients who agreed to undergo chemotherapy formed Group A and the remaining formed Group B. Therefore, the study was a non-randomized prospective comparison between patients receiving chemotherapy and those offered the best supportive care. Group A consisted of 42 patients; 19 underwent Roux-en-Y operation, and 23 were inoperable. Group B consisted of 48 patients who refused chemotherapy; 18 underwent Roux-en-Y operation, and 30 were considered inoperable. Chemotherapy consisted of FA 200 mg/m2/day, 5-FU 600 mg/m2/day both for 5 days, and EPI 35 mg/m2/day before FA-5-FU administration on days 1 and 2, every 28 days. All patients were evaluable for response and toxicity. Objective tumor responses (partial responses) in Group A were seen in 8 patients (19%) (6 women and 2 men), and 6 (14%) had stable disease. The estimated median survival was 27.6 weeks (mean 27.5) for Group A and 22.5 weeks (mean 24) (p=0.01) for Group B. From the onset of therapy, median duration of response was 16.6 weeks and median time to progression 11.8 weeks in Group A. Toxicity consisted primarily of myelosuppression, nausea and vomiting, diarrhea, alopecia, and mucositis. In Group A 12/42 patients became free from pain for a median duration of 10 months, 14/42 had improved appetite, and 15/42 had improved performance status in comparison to Group B, where no patients had improved performance status or symptoms. We conclude that the combination of EPI+FA+5-FU has moderate activity and increased toxicity in the treatment of advanced pancreatic cancer.

Adult↗
PubMed1998

A comparative study of three variations of the learning vector quantizer in the discrimination of benign from malignant gastric cells.

A prospective study was undertaken to investigate the potential value of morphometry and artificial neural networks (ANN) for the discrimination of benign and malignant gastric lesions. Two thousand five hundred cells from 23 cases of cancer, 19 cases of gastritis and 58 cases of ulcer were selected as a training set, and an additional 8524 cells from an equal number of cases of cancer, gastritis and ulcer were used as a test set. Images of routine processed gastric smears stained by the Papanicolaou technique were processed by a custom image analysis system. The application of the learning vector quantization (LVQ) classifier enabled correct classification of > 97% of benign cells and > 95% of malignant cells, obtaining an overall accuracy of > 97%. This study presents the capabilities of ANN, and also indicates that ANN and image morphometry may offer useful information on the potential of malignancy in gastric cells.

Cell Differentiation↗