Biomedical subjects

G Meimarakis

Publications and source records attributed to G Meimarakis.

10 recordsLinked to original sources

PubMed2006

Results of different operative procedures for patients with popliteal artery aneurysms.

BACKGROUND: Long term results of four different operative procedures for the treatment of popliteal artery aneurysms were investigated either performed by short venous or segmental alloplastic interpositions or long femoro-popliteal below the knee bypass using alloplastic grafts or autologous vein. PATIENTS AND METHODS: 47 patients treated for 50 popliteal aneurysms (mean diameter +/- SD: 3.5 +/- 1.1 cm) were analyzed (follow-up: 40.2 +/- 4.9 months). RESULTS: Primary patency rate was 78% and secondary patency rate was 86% at 5 years. Frequency of operative reinterventions was higher in patients treated for acute ischemia and in patients treated with alloplastic interpositions or alloplastic bypass (p = 0.026). Secondary patency rates were higher in patients treated with autologous venous interpositions or venous femoro-popliteal bypass (p = 0.022). Times of secondary vascular patency were significantly shorter for patients treated with short alloplastic interpositions in comparison to long alloplastic femoro-popliteal bypass procedures, short venous interpositions or long venous bypass operations (p = 0.018). CONCLUSIONS: For the treatment of patients with popliteal aneurysms autologous venous interposition is therefore recommended or as an alternative venous or alloplastic femoro-popliteal below the knee bypass.

Amputation, Surgical↗

PubMed2004

[Diagnostic evaluation of carotid artery stenoses with multislice CT angiography. Review of the literature and results of a pilot study].

BACKGROUND: The accurate evaluation of carotid artery stenoses is important for therapeutic decision making. Catheter digital subtraction angiography (DSA) still represents the gold standard, while the advent of multislice CT (MSCT) has led to improved temporal and spatial resolutions of CTA. MATERIAL AND METHODS: In a pilot study, we investigated 14 diseased vessels in 9 symptomatic patients (7m, 2f; mean age 60.7+/-10,9 years) comparing biplanar DSA with standardized 16-slice MS-CTA. The degree of stenosis was evaluated in a consensus reading following modified NASCET criteria. RESULTS: DSA demonstrated 4 occlusions, 5 high-grade stenoses (>70%) and 5 lower-grade stenoses (<70%). One dissecting, infrapetrous stenosis was not adequately quantified by CTA due to a close topographic relation to the skull base. In the carotid bifurcation (n=13), an excellent correlation was demonstrated between DSA and CTA with a correlation coefficient of 0.99. CONCLUSION: MS-CTA has a good diagnostic potential in the evaluation of carotid artery stenoses. Larger studies will need to demonstrate the relative diagnostic value for different subtypes of stenosis and for different reader experience levels.

Aged↗

PubMed2004

Colorectal cancer patients before resection of hepatic metastases. Impact of (18)F-FDG PET on detecting extrahepatic disease.

AIM: Evaluation of the role of FDG-PET in comparison to conventional staging methods for detecting extrahepatic tumour deposits prior to resection of liver metastases. PATIENTS, METHODS: In our prospective study, 58 patients (24 women, 34 men; age 33-81 years) with liver metastases of colorectal carcinoma underwent FDG-PET. Images were acquired in 3D-mode including transmission scans and reconstructed iteratively. For conventional staging all patients underwent abdominal ultrasound, helical computed tomography (CT) of the thorax and abdomen, and colonoscopy/rectoscopy. A preliminary therapeutic decision was established without knowledge of the FDG-PET findings. Thereafter, it was revised or confirmed according to the results of FDG-PET. RESULTS: In 3/58 patients extrahepatic tumour deposits were concordantly identified with both conventional staging methods and FDG-PET. However, in one case, both conventional methods and FDG-PET were false positive regarding pulmonary metastases. In 12/58 patients, nothing but FDG-PET detected extrahepatic tumour masses, which were later confirmed either by histology or follow-up. CONCLUSION: Our study suggests that in 21% of patients exclusively FDG-PET is an appropriate diagnostic tool to reveal extrahepatic metastases or local recurrence of colorectal carcinoma. Our results demonstrate that FDG-PET provides relevant additional information for accurate therapeutic planning as compared to the conventional combination of staging methods. Therefore, FDG-PET has to exert a decisive influence on the decision for resection of hepatic metastases.

Adult↗

PubMed2003

[Surgical treatment of pulmonary metastases from renal cancer].

Based on a large single-center follow-up database, we evaluated the long-term results after curative resection of pulmonary metastases from renal cancer. During a 20-year period, 105 patients underwent a total of 150 resections with curative intention. Hospital mortality was 0.95%, 5- and 10-year survival rates were 40% and 33%, respectively. Significant prognostic relevance was shown for complete pulmonary resection, lymph node involvement upon primary resection as well as size of the resected lung metastasis. Our findings of low perioperative morbidity and mortality rates lead us to propose that in patients without additional metastases curative resection of pulmonary lesions should be considered. Moreover, recurrent pulmonary metastases should also be considered for surgical treatment since resection for cure significantly improves survival in these patients.

Adult↗

PubMed2001

[Dissection techniques in liver surgery].

The first liver resection was performed in 1888. Since then a wide variety of dissection techniques have been introduced. The blunt dissection was replaced by novel methods, i.e. the CUSA technique and the Jet Cutter for major liver resections. These methods represent selective dissection techniques; whereas non-selective methods include the scalpel, scissors, linear stapling cutter, high-frequency coagulation, and the laser technique. The aim of this review article is the comparison of the different resection techniques in liver surgery, focussing on blood loss and resection time.

Blood Loss, Surgical↗

PubMed2001

Silent cerebral infarction: risk factor for stroke complicating carotid endarterectomy.

"Silent" cerebral infarction is found in 20% to 30% of patients with significant internal carotid artery (ICA) disease. Our purpose was to determine whether such "silent" cerebral infarction in the operated carotid territory represents a risk factor for stroke during and immediately after carotid endarterectomy. Over 5 years we followed a cohort of 663 patients with symptomatic and asymptomatic ICA stenosis who were consecutively scheduled for surgery. The stenosis was more than 70% in patients with transient ischemic attacks and more than 95% in asymptomatic stenosis patients. All patients underwent preoperative computed tomography to determine the frequency, extent, and location of any "silent" cerebral infarction. Patients were grouped by the absence or presence of infarction in the operated carotid territory. Among the entire cohort, 20 patients had a major perioperative stroke (3.0%). All deaths were stroke-related. No intracranial bleeding occurred. Major stroke occurred in four (0.8%) patients without appropriate "silent" cerebral infarction, compared with 16 (8.8%) with an appropriate "silent" cerebral infarct (p < 0.001). After adjustment for confounding co-variables (e.g., gender, presence of preoperative symptoms, and age), "silent" cerebral infarction was found to be the only independent predictor of perioperative major stroke for symptomatic and asymptomatic stenosis (overall adjusted relative risk 11.5, 95% confidence interval 3.8-34.9, p < 0.0001). Patients with "silent" cerebral infarction seem to be at increased risk of perioperative stroke. Consequently, preoperative cerebral imaging is important for risk classification.

Aged↗

PubMed2000

Long-term results after video-assisted thoracoscopic surgery for first-time and recurrent spontaneous pneumothorax.

BACKGROUND: Few investigators have reported on results after video-assisted thoracoscopic surgery (VATS) for spontaneous pneumothorax (SP) with follow-up periods longer than 24 months. The aim of this study was to evaluate VATS for first-time and recurrent SP and to follow patients long-term. METHODS: One hundred nine patients were followed long-term after treatment of SP by VATS. Ninety-five patients had primary SP and 14 had secondary SP. Sixty-two patients had a first episode and 47 had a recurrence. In 72 patients leaks or ruptured blebs were identified and excised without subsequent pleurodesis. In 37 patients showing no ruptured bullae or leaks only pleurodesis was applied. RESULTS: Median follow-up was 53.2 months. Postoperative complications were rare. Three patients (2.7%) had a prolonged air leak. The long-term recurrence rate was 4.6%. Only those patients who had not received pleurodesis at the time of first treatment by VATS experienced recurrence. CONCLUSIONS: Immediate postoperative results show VATS to be a safe and reliable method in first-time and recurrent SP to obtain quick reexpansion of the lung. Long-term recurrence rates are acceptable and compare with results after open thoracotomy. Pleurodesis should be included in each procedure for adequate recurrence prevention.

Adult↗

PubMed1997

Pattern of adhesion molecule expression on vascular endothelium in Helicobacter pylori-associated antral gastritis.

BACKGROUND & AIMS: The inflammatory response in Helicobacter pylori-associated gastritis (HAG) is characterized by an intense infiltrate of granulocytes and lymphocytes. The emigration of white blood cells into sites of inflammation is mediated by receptors on endothelial cells and on blood leukocytes. The aim of this study was to characterize endothelial adhesion molecule expression in HAG leading to leukocyte infiltration. METHODS: Endothelially expressed adhesion molecules were studied in situ by immunohistochemical analysis of antral mucosal biopsy specimens from 20 control patients, 10 of whom had chemical gastritis, 10 normal mucosa, and 44 HAG. Adjacent biopsies were used to evaluate messenger RNA (mRNA) transcripts for the respective adhesion molecule and its inducing cytokines. RESULTS: Constitutive expression of P-selectin was found in all groups. Intercellular adhesion molecule 1 (ICAM-1) was up-regulated in patients with HAG and chemical gastritis in contrast to normal controls. Vascular adhesion molecule 1 (VCAM-1) was only found within lymphoid aggregates present in HAG. Neither mRNA transcripts nor the protein product of E-selectin were detected in normal or inflamed mucosa, although mRNA of the E-selectin-inducing cytokines, tumor necrosis factor alpha and interleukin 1beta, were found. CONCLUSIONS: Data suggest a major role of ICAM-1 and VCAM-1 in leukocyte-endothelial interaction in HAG without E-selectin up-regulation showing a unique pattern within the gastrointestinal tract, in contrast to observations made in inflammatory bowel disease.

Adult↗

PubMed1996

Granulocyte activation by Helicobacter pylori.

Helicobacter pylori-associated gastritis (HAG) is characterized by granulocytic and mononuclear cell infiltrates within infected gastric mucosa. Since the bacterium does not invade the epithelial layer, it must be assumed that components or products of the pathogen which permeate the epithelial barrier may initiate chemotaxis and activation of neutrophils. The aim of this study was to evaluate the effect of H. pylori water soluble protein (WSP) components on the induction of granulocyte adherence and activation. The results show that H. pylori WSP led to enhanced expression of the beta 2-integrin CD11b/CD18 on the granulocyte surface. Following upregulation of this adhesion molecule, activated granulocytes demonstrated increased adhesion to human endothelial cells (HUVEC) in culture. These observations support the hypothesis that in vivo neutrophil activation may be a direct result of H. pylori constituents promoting transendothelial migration into the lamina propria of infected gastric mucosa.

Bacterial Proteins↗

PubMed1996

Characterization of lymphocytic infiltrates in Helicobacter pylori-associated gastritis.

BACKGROUND: This study evaluated the specific subset composition of lymphocytes present in Helicobacter pylori-associated gastritis (HAG), since reports so far have led to inconclusive and conflicting results. METHODS: Endoscopic biopsy specimens from 56 patients were studied by quantitative immunohistochemistry using monoclonal antibodies against the lymphocyte markers CD3, CD22, CD4, CD8, CD45RO, CD1O3, TCR alpha/beta, and TCR gamma/delta. Lamina propria and intraepithelial compartments were evaluated separately. Grade, activity, and density of bacterial colonisation were assessed histologically and with Warthin-Starry stain. RESULTS: Evaluation showed a significant increase in CD4+, CD45RO+, TCR alpha/beta+ activated lamina propria lymphocytes in HAG which correlated with grade and activity of gastritis and degree of bacterial colonisation, whereas subsets of intraepithelial lymphocytes did not change significantly. TCR gamma/delta+ T cells were not found to be increased in HAG. CONCLUSIONS: Selective expansion of CD4+, CD45RO+ memory-type T cells could reflect an antigen-specific and/or chemokine-mediated effect in HAG. Locally produced CC chemokines such as RANTES have been detected in HAG.

Adult↗