Biomedical subjects

I Tsolakis

Publications and source records attributed to I Tsolakis.

7 recordsLinked to original sources

PubMed2007

Dynamic F wave study in patients suffering from peripheral arterial occlusive disease.

OBJECTIVE: To prospectively detect significant transient F wave abnormalities obtained after exercise in patients with peripheral arterial disease (PAD) and to assess the potential diagnostic sensitivity of dynamic F wave study in such a context. PATIENTS AND METHODS: A series of 40 electrical stimuli were delivered to the peroneal and the posterior tibial nerves of 25 patients with PAD in order to obtain F waves at rest and post-exercise. The following variables were estimated and the obtained pre- and post-exercise data were compared: F persistence, F wave latency, amplitude, duration and F chronodispersion. For each nerve studied, the minimum, average and maximum values were calculated. Conventional electrophysiological data were also collected pre- and post-exercise and the data obtained were also compared. Twenty-five healthy age-, gender- and height-matched individuals served as controls. RESULTS: No evidence of conventional nerve conduction abnormalities was recorded either pre- or post-exercise in the group of patients. As regards the peroneal nerve, the significantly reduced F wave persistence (P = 0.007) and maximum F wave amplitude post- as opposed to pre-exercise (P = 0.05)- were the main findings to emerge. The average (P = 0.017) and the minimum duration (P = 0.005) of tibial F waves were also significantly increased post- compared with pre-exercise. Insignificant differences were observed between pre- and post-exercise neurophysiological and F wave values in the group of controls. CONCLUSION: Given the observed absence of conventional neurophysiological abnormalities, the detection of dynamic F wave changes supports the view of an increased diagnostic sensitivity of this method in patients with mild PAD.

Adult↗

PubMed2005

Effects of carotid endarterectomy on motor evoked potentials elicited by transcranial magnetic stimulation.

PURPOSE: To investigate the within 3 days effects of carotid endarterectomy (CEA) on functional status of the central motor system in patients with carotid stenosis by means of transcranial magnetic stimulation (TMS). PATIENTS AND METHOD: We studied 30 consecutive patients, 20 males and 10 females with a mean age of 69.2+/-7.1 years, who underwent CEA for symptomatic carotid stenosis. All patients had suffered an ischemic attack 6 months prior to the operation. Two TMS studies, one before and one shortly after CEA were performed on both sides in each of the patients. Resting motor threshold, motor evoked potentials (MEP) amplitude at rest, MEP latency at rest and during contraction and silent period duration (SPD) were recorded and analyzed. Two groups of data were collected. Group 1 consisted of data from the operated side in all 30 patients. Group 2 consisted of data from the contralateral side and served as a control. RESULTS: Motor resting thresholds were similar in the two groups. Intragroup pre and post CEA comparisons showed no difference in the operated group and significant increased threshold after CEA on the non-operated side. There was no significant difference of TMS intensity for maximal MEP in either side before or after CEA. Latency at rest and during voluntary contraction and amplitude at rest showed no significant differences between or within groups' comparisons. In group 1 SPD showed a statistically significant increase after CEA as opposed to baseline. In group 2 SPD showed a non significant increase after CEA. CONCLUSION: In the absence of other MEP changes, our finding of prolonged SPD post-operatively suggests preferential influence of the inhibitory cortical circuits. The potential favorable effect of CEA in patients with hyperexcitability such as disabling spasticity after stroke should be further studied.

Aged↗

PubMed2003

Versican undergoes specific alterations in the fine molecular structure and organization in human aneurysmal abdominal aortas.

Versican is the major matrix proteoglycan in aortic wall and participates in various biological functions of the tissue. In the present study the molecular characteristics of versican isolated from normal human aorta as well as those of versican expressed in aneurysmal aortic tissue were examined. Versican was isolated by combined anion-exchange and gel permeation chromatography and was further characterized by high-performance liquid chromatography, polyacrylamide gel electrophoresis and immunoblotting. In both tissues versican is exclusively substituted with chondroitin sulfate chains, in contrast to other human tissues where both chondroitin and dermatan sulfate chains are attached onto versican core proteins. Except for the significant decrease in the concentration of versican in the aneurysmal tissue, this PG undergoes specific alterations in the aneurysmal tissue. The molecular size of versican isolated from diseased tissue is decreased with a simultaneous increase in the ratio of glycosaminoglycan to protein in this tissue. The latter reflect the extensive fragmentation of versican in the diseased tissue and most probably the generation of shorter peptides enriched to glycosaminoglycan chains. Although the size of chondroitin sulfate chains is identical in both versican preparations, a significant increase in the percentage of 6-sulfated disaccharides is observed in chondroitin sulfate chains of versican in aneurysmal aortas, which is accompanied by decrease in 4-sulfated and non-sulfated units.

Aged↗

PubMed2001

Human abdominal aortic aneurysm is characterized by decreased versican concentration and specific downregulation of versican isoform V(0).

Abdominal aortic aneurysm (AAA) is a common disease of human aorta with increased incidence. It is a complication to atherosclerosis and it is closely associated with alterations in extracellular macromolecules. In this study, the levels of mRNA for versican--the major extracellular arterial proteoglycan (PG)--present in AAA and normal aortas were evaluated by reverse-transcriptase polymerase chain reaction. The concentration of versican was also examined in corresponding tissue samples. Versican was almost completely extracted with 4 M guanidine hydrochloride in the presence of Triton X-100, isolated by chromatography on DEAE-Sephacel and characterized using treatment with specific chondro-/dermato-lyases and agarose gel electrophoresis. Versican localization in tissue as well as the variation and distribution of smooth muscle cells (SMCs) and macrophages were also investigated immunohistochemically. The mRNAs coding for versican isoforms V(0) and V(1) were identified in both tissues, whereas V(2) was absent. The expression of V(0) was decreased 40% in aneurysmal vessel wall, whereas that for V(1) remained constant. This change was simultaneous with a significant decrease in versican concentration by 89%. In normal aortas, most versican was seen in the intima, whereas in AAA, this layer is characterized by advanced atherosclerotic lesion, rich in lipids and macrophages but poor in versican. The decreased transcription and the still lower amount of versican in the AAA may correlate to (i) a decrease in density of SMCs, these cells being the major source of versican in aorta, and (ii) the presence of macrophages, which may induce versican degradation and modulate versican synthesis. It is proposed that the decreased synthesis and increased degradation of versican, particularly of isoform V(0), and the resulting low concentration in the intima are crucial factors contributing to the altered viscoelastic and compressive properties and thereby to the deformity and dilatation of aorta.

Adult↗

PubMed1999

Human abdominal aortic aneurysm is closely associated with compositional and specific structural modifications at the glycosaminoglycan level.

Human abdominal aortic aneurysm (AAA) is a commonly occuring disease of blood vessels and is related to alterations in extracellular matrix molecules. In this study we report on the type and fine structural characterization of glycosaminoglycans (GAGs) present in AAA as compared with those present in normal abdominal aorta. Hyaluronan (HA), the galactosaminoglycans-chondroitin sulfate (CS) and dermatan sulfate (DS) with average molecular size (Mr) of 35-kDa-as well as heparan sulfate (HS) with Mr of 40-kDa were identified in both tissues. No significant intrabatch differences in total GAG content were identified in normal and aneurysmal aortas. Comparing, however, tissue composition and structure of GAGs between AAAs and normal aortas, significant differences (P < or = 0.001) were found. The overall GAG content in AAAs was approx. 60% lower than the normal ones. A 90% decrease in HS content, and 65 and 73% in CS and HA, respectively, were also recorded. In contrast, only a slight decrease in the amount of DS was noted (8%). Structural alterations in disaccharide composition of GAGs correspond mainly to significant decreases (P < or = 0.001) of HS-derived N-sulfated disaccharides, CS-derived 6-sulfated disaccharide and DS-derived disulfated disaccharides. These results demonstrate that the development of AAA is related to dramatic quantitative and structural modifications at the GAG level and this may well be attributed to the destruction of arterial wall architecture and further significant functional inadequacies of the tissue.

Aged↗

PubMed1998

Simultaneously occurring abdominal aortic aneurysm and invasive transitional cell carcinoma of the bladder and their synchronous management.

We report the case of a 70-year-old man who presented with an abdominal aortic aneurysm and invasive transitional cell carcinoma of the bladder. Synchronous surgical treatment was deemed necessary because of the iliac extension of the aneurysm. Radical cystectomy preceded the repair of the abdominal aortoiliac aneurysm and the bilateral cutaneous ureterostomy.

Aged↗

PubMedDate not supplied

Acute rupture of an aortic aneurysm mimicking the discus hernia syndrome. A case report.

Aneurysms of the abdominal aorta have been recognised as a cause of back pain and vertebral erosion. However back pain and paraplegia are uncommon, presenting complaints in patients with aortic aneurysms. A case of acute rupture of an abdominal aortic aneurysm is presented mimicking the symptoms of a discus hernia syndrome and paraplegia.

Aortic Aneurysm, Abdominal↗