Search PubMed⌕ Search

Biomedical subjects

G Bauriedel

Publications and source records attributed to G Bauriedel.

At least 91 records · Page 5Linked to original sources
PubMed1991

[Current status of directional coronary atherectomy in interventional cardiology].

Directional coronary atherectomy (DCA) was used in 74 patients with an average age of 56 years. They were categorized into three different groups depending on the indications for atherectomy. Group I included all patients who had atherectomy as their primary intervention (n = 26), because they were assumed to be unsuitable for PTCA. Group II consisted of patients in whom DCA was used after failed balloon dilatation with unsuccessful but uneventful treatment (n = 20). Group III (n = 28) included cases where DCA was performed as a "rescue" or "bail-out" procedure after failed PTCA resulted in critical ischemia (ECG changes, chest pain, hypotension, and shock). The target lesions were located in LM 2, LAD 52, RCA 16, ACVB 4. The mean length of lesion was 8 mm (2-25 mm). The overall success rate was 94%. The mean stenosis was reduced from 90.6 +/- 10% to 17.2 +/- 14.8% in cases with primary success. The presently available follow-up angiography (n = 31) showed six restenoses. Major complications occurred in seven cases (death: 0, myocardial infarction: 2, CABG within 24 h: 5). Histological analysis revealed highly cellular areal as a major characteristics of a coronary lesion and also of restenotic tissue. Tissue of the lamina elastica was present in 44% and of media in 14%. Thrombus was found only rarely. Ultrastructure showed a significant amount of extracellular matrix in the primary coronary lesions and isolated smooth muscle cells without gap-junctions. RER, mitochondria were typical for the synthesizing type of smooth muscle cell. In restenotic tissue a focal high density of smooth muscle cells with increased synthesizing activity and gap-junctions was present. Endothelial cells (and macrophages) were found only rarely. Furthermore, altered smooth muscle cells from restenotic tissue showed a significantly increased migration and proliferation. Our results show that DCA is a safe and effective technique that can extend the use of percutaneous procedures and provide a promising, nonsurgical option in cases of failed PTCA. Histological analysis revealed a proliferative process as a characteristics of restenosis development.

Angioplasty, Balloon, Coronary↗
PubMed1991

[Directional coronary atherectomy: acute results and angiography follow-up in 42 treated patients].

We used directional coronary atherectomy (DCA) as a therapeutic option for coronary lesions unsuitable for PTCA (eccentric, ostial, branching or restenotic) and as "rescue device" for failed PTCA. Forty-two patients were treated by DCA using the Simpson coronary atherectomy device, including four female and 38 male patients with an average age of 55.7 years. Atherectomy as primary intervention was performed in 16 patients (Group I), because morphology of their lesions was assumed to be unsuitable for PTCA. DCA was also used after failed balloon dilatation in eight patients with unsuccessful, but uneventful treatment (Group II). In 18 cases (Group III) DCA was performed as "rescue procedure" after failed PTCA and resulting critical ischemia (local dissection, signs and symptoms of ongoing ischemia, occlusion after PTCA). Target lesions were located in LM 1, LAD 33, RCA 9, CABG 3. Mean length of lesion was 8.1 mm (2-25 mm). The overall success rate for 46 lesions was 93%. Mean stenosis was reduced from 92% to 17% in cases with primary success. Presently, available follow-up angiography (24) showed six restenoses (defined as greater than 50% stenoses). Major complications occurred in seven cases (death: 0, MI: 2, CABG within 24 h: 5; 3 in Group III). "Rescue indication" (Group III) after failed balloon dilatation procedure showed a favorable primary result with a success rate of 78%; only three cases of this group needed CABG. Our results show that DCA is a safe and effective technique which can extend the indication for percutaneous procedures and gives a successful nonoperative option in cases of failed PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1991

[Increased in vitro motility of human vascular wall myocytes from restenotic lesions of peripheral and coronary vessels].

In this study we report on the successful cultivation of human peripheral and coronary plaque specimens selectively retrieved by percutaneous Simpson atherectomy and obtained by direct operative approach. A total of 32 patients in whom plaque tissue was excised from 22 primary and 10 restenotic lesions comprise the study population. Irrespective of their origin or location, all advanced lesions showed smooth muscle cells (SMC) to be their predominant cell type proven by indirect immunofluorescence technique. Cultured endothelial cells were only identified in 2/6 surgically removed samples. Locomotion analysis of cultured smooth muscle cells was performed with a standardized computer-assisted video system. Cells of all groups exhibited random motility. However, SMC migratory velocity of restenotic origin amounted to 47.4 +/- 3.4 microns/h (n = 10, x +/- SD) and thereby was found 2.4 times (p less than 0.001) increased as compared to primary lesion values of 22.0 +/- 3.7 microns/h (n = 22, x +/- SD). This highly significant difference was seen for both peripheral and coronary lesions. Our data suggest increased SMC migratory activity to represent a basic biological mechanism involved in human accelerated arteriosclerosis and restenosis formation.

Aged↗
PubMed1989

[Possibilities of arterioscopy].

Today, technically optimized fiberoptical systems have become available for direct visualization of the arterial inner wall. The increasing significance of interventional revascularization techniques opens the door to new adjuvant diagnostic and therapeutic indications for arterioscopy, in addition to the earlier mainly intraoperative use. Especially for vascular wall reconstruction with percutaneous atherectomy, the angioscopic identification of residual intraluminal plaque material helps to optimize the procedure. On the basis of our own experience, a critical evaluation of arterioscopy is presented.

Arterial Occlusive Diseases↗
PubMed1989

Cell constitution and characteristics of human atherosclerotic plaques selectively removed by percutaneous atherectomy.

The Simpson atherectomy device used for the recanalization of severely stenosed peripheral arteries is able to collect plaque material which can be further characterized. This study reports histological, immunohistochemical and transmission electron microscopic findings on advanced human primary atherosclerotic plaques of peripheral arteries percutaneously removed by a Simpson atherectomy catheter. Material from stenosing plaques consisted of dense connective tissue with abundant amounts of concentrically arranged elastic fibers and lamellae. This meshwork contained numerous cells, often arranged in clusters and oriented with their longer axis parallel to the direction of blood flow. The vast majority of these cells could be easily identified as vimentin-positive and desmin-negative smooth muscle cells containing lipid deposits in the perinuclear region and numerous glycogen particles. Monocytes/macrophages were observed only very infrequently. Plaque tissue contained a range of smooth muscle cell phenotypes. Most of the cells were of an intermediate phenotype, i.e. sparsely filled with myofilament bundles at the cell periphery and a high amount of organelles such as mitochondria, rough endoplasmic reticulum and Golgi cisterns. An intact lining of pieces of intimal tissue with endothelial cells was not observed. Two-dimensional gel electrophoresis of plaque tissue showed the presence of alpha-, beta- and gamma-actin isoforms with a clear predominance of the beta-isoform.

Arteriosclerosis↗
PubMed1982

Stimulatory (insulin-mimetic) and inhibitory (ouabain-like) action of vanadate on potassium uptake and cellular sodium and potassium in heart cells in culture.

(1) The influence of vanadate (Na3VO4) on sodium and potassium uptake as well as on cellular ion contents of sodium and potassium has been studied in heart muscle and non-muscle cells obtained from various species. An ouabain-like inhibition of potassium uptake (up to 50%), combined with a decrease of cellular potassium (up to 20%) has been observed by vanadate (10(-4)-10(-3) M) in heart non-muscle cells obtained from neonatal guinea pigs and chick embryos. In heart muscle and non-muscle cells prepared from neonatal rats, as well as in Girardi human heart cells, a vanadate-induced stimulation of potassium uptake (up to 100%), combined with a rise in cellular potassium (up to 20%) and without significant alteration of cellular sodium, has been found. A slight increase of 22Na+ influx can be measured in rat heart muscle cells and in Girardi human heart cells in the presence of vanadate (10(-4)--10(-3) M). (2) In beating rat heart muscle cells in culture, detrimental effects of serum deprivation--concerning beating properties, potassium uptake and cellular potassium--can at least in part be overcome by addition of vanadate. Furthermore, this compound prevents ouabain-induced signs of toxicity (contractures) in these cells. (3) The stimulatory effects of vanadate on potassium can be mimicked by insulin (1-10 mU/ml). Furthermore, vanadate produces an insulin-like stimulation of 2-deoxy-D-glucose uptake in rat heart muscle and non-muscle cells as well as in Girardi human heart cells. (4) The experimental data demonstrate an ouabain-like inhibition as well as an insulin-mimetic stimulation of potassium-uptake in various heart cells. The reason for this antagonistic mode of action may be due to the different capabilities of the heart cell types to reduce vanadium in the V-valence state of vanadium in the IV-valence state, thereby favouring either ouabain-like inhibition (vanadium V) or insulin-mimetic stimulation (vanadium IV) of potassium transport.

Animals↗
PubMed1980

Effects of vanadate in cultured rat heart muscle cells. Vanadate transport, intracellular binding and vanadate-induced changes in beating and in active cation flux.

Cultured rat heart muscle cells have been used to study uptake and intracellular binding of Na483VO4 (vanadate), as well as the influence of vanadate on beating and 86Rb+ uptake of these cells. 1. Vanadate is taken up into cultured rat heart muscle cells in an energy-independent manner by a saturable transport system (Km approximately 60 microM, V approximately 200 pmol per mg protein per min at 37 degrees C). Analysis of intracellular binding of vanadate reveals a curved Scatchard plot indicating more than one binding site. Maximal binding amounts to 3 . 10(9) molecules of vanadate per cell. 2. Vanadate exerts a positive chronotropic and inotropic effect and increases automaticity. First effects can be seen at 1 . 10(-7) M Na3VO4. Concentrations higher than 1. 10(-3) M induce toxic effects (arrhythmias, fibrillation and stand-still of the cell). 3. Vanadate-induced alterations of beating is paralleled by a vanadate-induced stimulation of (86Rb+ + K+) uptake into the cells of up to 75%. Maximal stimulation is obtained at concentrations of 1 . 10(-4)--1 . 10(-3) M vanadate. The stimulation is thought to be due to an increased activity of (Na+ + K+)-ATPase, since it can be inhibited by ouabain. This result is in contrast to in vitro experiments with purified membrane preparations of (Na+ + K+)-ATPase of different organs, where an inhibition of (Na+ + K+)-ATPase by vanadate has been found. 4. The results indicate a possible role of vanadate as an endogenous regulator of active cation flux in heart tissue.

Animals↗
PubMedDate not supplied

Selective percutaneous "biopsy" of atheromatous plaque tissue for cell culture.

The combination of percutaneous atherectomy and angioscopy enabled a selective "biopsy" of protruding atheromatous plaque material from 11 patients with arterial occlusive disease. The removed specimens were cultivated as adhering explants or single cells were obtained by enzymatic disintegration. The vast majority of the cultivated cells resembled fibroblasts, but could be identified as smooth muscle cells by their smooth muscle alpha-actin content. Proliferation rate was slow with 0.1 doublings per day. Endothelial cells were not observed by immunologic criteria. The described biopsy technique and in vitro evaluation of cultured human atheromatous plaque material may be useful for a better understanding of atherogenesis.

Actins↗
PubMedDate not supplied

Regulation of active cation flux by vanadate in beating rat heart muscle cells in culture.

Looking for a supposed digitalis-like action of compounds of the trace element vanadium, we have investigated the influence of vanadate (Na3VO4) on beating and on active cation flux of [42K+] and [89Rb+] in cultured rat heart muscle cells: Na3VO4(10(-6)-10(-3)M) exerts a positive chronotropic effect and increases contraction velocity and beating automaticity of the cells. Vanadate-induced alteration of beating is paralleled by stimulated uptake of [42K+] and [86Rb+] up to 75%. This stimulation has to be attributed to increased activity of (Na++)-ATPase and cannot solely be explained by the enhanced beating frequency. In contrast to ouabain, vanadate raises intracellular potassium content up to 15% and prevents cell contractures of ouabain-intoxicated heart muscle cells. The experimental data speak against a possible digitalis-like action of vanadate in cultured rat heart muscle cells.

Animals↗