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C Mrowietz

Publications and source records attributed to C Mrowietz.

At least 37 records · Page 2Linked to original sources
PubMed2000

Haemocompatibility of coronary catheters.

BACKGROUND: Unwanted side-effects like thrombotic-thromboembolic processes accompany the intravascular use of catheters. The influence of the physico-chemical properties of the catheter materials on these processes is not completely understood. METHODS: The haemocompatibility of angiography-catheters (n = 10) (Super Torque Plus, CORDIS, Johnson & Johnson company) was examined in a perfusion-model filled with platelet-rich plasma and either compared to a non-thrombogenic (silicon-tube) or to a thrombogenic surface (glass). As test-parameters the number of single circulating thrombocytes, of circulating platelet-aggregates, of circulating activated thrombocytes (CD62) and the thrombin generation (thrombin antithrombin III-complexes) were evaluated. RESULTS: None of the test-parameters showed differences between the non-thrombogenic control-system and the angiography-catheters. Both systems, however, differed significantly and relevantly from the system filled with the glass-beads (the thrombogenic control-systems). CONCLUSION: With respect to the platelet reactivity angiography-catheters of the examined type can therefore be regarded as non-thrombogenic or haemocompatible.

Cardiac Catheterization↗
PubMed2000

Capillary microscopic and rheological dimensions for the diagnosis of von Willebrand disease in comparison to other haemorrhagic diatheses.

It is known that angiodysplasia influence macrocirculation as well as microcirculation in patients with vWD. In the present study it was examined if intravital capillary microscopic dimensions (morphologic and dynamic) in skin (nailfold) in combination with rheologic parameters could give indications for the presence of vWD in patients with haemorrhagic diathesis. Patients with vWD (n = 100; 92 type 1: definite type 1:78 and possible type 1:14: 8 type 2A) have in comparison to patients with other haemorrhagic diathesis [thrombocytopathy (n = 122), thrombocytopenia (n = 101). severe haemophilia A (n = 50) and severe haemophilia B (n = 20). congenital dysfibrinogenaemia (n = 22), oral anticoagulation with phenprocoumone (n = 112)] and to apparently healthy subjects (n = 100) a significantly increased capillary torquation (median index: 3.5), a venolar and an arteriolar capillary dilatation (median: 16.5 microm; median: 15.1 microm) and the highest part of microscopic bleedings (extravasates) with 40% in the video capillary microscopy as morphological changes. Only the congenital dysfibrinogenaemia appears with a larger dilatation in venolar capillaries (median: 14.5 microm). Microscopic bleedings are much less common in other haemorrhagic diatheses with a frequency between 4% and 13%. In the vWD a significantly reduced duration of reactive hyperaemia (median: 150 sec). This is the only dynamic change that can be taken as a possible hint for a loss of flexibility within the precapillary vessels. A significantly reduced plasma viscosity (< 1.25 mPas) is typical for the vWD due to the increase of the shear stress in blood plasma because of the reduction of vWF-activities. Changes of the capillary morphology (dilatation, extravasates, capillary torquation) and the hypoplasmaviscosity are most sensitive for the vWD (75%, 65%, 40%, 80%) with a fairly high specifity (up to 93%) and a positive predictive value of 99%. As a conclusion it seems reasonable to discuss the introduction of video capillary microscopy as a screening test for haemostasiological and angiological centers.

Adult↗
PubMed1999

Effect of X-ray contrast media on blood flow properties after coronary angiography.

In vitro studies suggest that ionic and nonionic X-ray contrast media have different effects on rheological parameters. The risk of thrombotic complications in coronary interventions was reported to be lower using ionic contrast media. The aim of the present study was to compare the effects of different types of contrast media on rheological parameters after coronary angiography. Sixty patients were randomized to four groups: ioxaglate 320 (dimeric, ionic, n = 18), iomeprol 400 (monomeric, nonionic, n = 12), iobitridol 350 (monomeric, nonionic, n = 12), and iodixanol 320 (dimeric, nonionic, n = 18). Blood samples were collected via the side port of the arterial sheath immediately before and at the end of coronary angiography. In our study, all types of contrast media caused a significant decrease in haematocrit (Hct), plasma viscosity (PV), erythrocyte aggregation (EA), and in the platelet reactivity index (PRI). The most pronounced decrease in Hct was found using the ionic dimer ioxaglate. There were no significant differences between the contrast media with respect to their effects on PV, EA, and PRI.

Aged↗
PubMed1999

Influence of radiographic contrast media (Iomeprol 350 versus Iopentol 350) on cutaneous microcirculation: single-center prospective randomized double-blind phase iv study in parallel-group design.

OBJECTIVE: This single-center, prospective, randomized, double-blind phase IV study in parallel-group design was carried out to investigate whether either of two different x-ray contrast media (iomeprol 350 or iopentol 350) injected into the axillary artery has any influence on cutaneous microcirculation. METHODS AND RESULTS: The investigation was carried out on two groups of patients (n = 10 in each group) who had to undergo a diagnostic heart catheter angiography. The confirmatory response variable for the study was the mean capillary erythrocyte velocity (mm/sec). Blood flow through the ipsilateral nail-fold capillaries was recorded continuously for 3 minutes before and 6 minutes after the injection of the randomly assigned x-ray contrast medium, and was evaluated off-line. A contrast medium-induced, rheologically determined disturbance of the microcirculation was found, which was due to two different effects. First, the high intrinsic viscosity (iopentol = 12.3 mPa.sec) led to an immediate reduction in capillary blood flow. This did not occur in the case of iomeprol (intrinsic viscosity = 7.5 mPa.sec). Second, the contrast medium molecules cause a morphological change in the erythrocyte membrane; echinocytes are formed and are further desiccated depending on osmolality of the contrast medium. CONCLUSION: The time course of the conversion of erythrocytes into echinocytes leads to a maximum reduction in capillary erythrocyte velocity of 30 seconds after the bolus of contrast medium. For the more viscous contrast medium of higher osmolarity (iopentol), this led to a significant overall reduction of up to 48.6% in capillary blood flow (p < 0.0001) that lasted for up to 150 seconds, while iomeprol did not significantly affect capillary blood flow (p = 0.2759).

Arteriosclerosis↗
PubMed1997

[Hemocompatibility of various synthetic granulates].

The adherence of platelets to different polymer granulates was examined in a perfusion chamber filled with platelet-rich plasma. The surface area of each of the granulates was of a standardised size. The results were compared with those found for a non-thrombogenic and a highly thrombogenic foreign-body surface. The three polymers examined-Cryolite, Styrolux and Zylar-must be considered non-thrombogenic. Platelet adherence to these substances is significantly less (3%) than that to a highly thrombogenic surface such as glass (95%). The three materials did not differ in terms of platelet adherence, and would appear to be suitable potential materials for use in cell separators.

Biocompatible Materials↗
PubMed1995

Plateletpheresis-induced increase in platelet reactivity using different cell separators.

OBJECTIVE: Since plateletpheresis is being used increasingly, it is important to regard quality control to check health risks for donors and to exclude these. DESIGN: Controlled randomised prospective open comparative study. SETTING: Department of Transfusion Medicine of a University Clinic. PARTICIPANTS: 112 platelet donors were examined. INTERVENTIONS: Prior to and after plateletpheresis platelet reactivity was determined. The platelet concentrates in the two groups of 56 donors each were produced using either the cell separator 'CS-3000' and the collecting chamber PLT 30TM with the Omnix system (group I) or the cell separator 'AS-104' (group II). RESULTS: In group I five donors showed a pathologically increased platelet reactivity (p = 0.1297) after plateletpheresis. In group II there were 10 donors with a pathologically increased platelet reactivity (p = 0.0046) after plateletpheresis. The mean concentration of platelets was reduced by separation using the CS-3000 Omnix from 238 +/- 49 x 10(3)/microliters to 172 +/- 32 x 10(3)/microliters (68 +/- 27 x 10(3)/microliters) and from 243 +/- 53 x 10(3)/microliters to 180 +/- 31 x 10(3)/microliters (63 +/- 33 x 10(3)/microliters) using the AS-104. In the first case the platelet yield was 3.9 x 10(11) platelets/concentrate, in the latter case it was 2.9 x 10(11) platelets/concentrate. The 'CS-3000 Omnix' is significantly more effective in separating (58.4 +/- 15.5%) than the 'AS-104' with 44.2 +/- 7.2% (p < 0.0001). CONCLUSIONS: Since both donor groups were comparable regarding all factors recorded--especially the cardiovascular risk factors--the separation process could be responsible for the different traumatisation of platelets.

Adult↗
PubMed1995

Influence of sonographic contrast media on microcirculation in rats.

In an open placebo-controlled study the influence of the injection of different sonographic contrast media on the microcirculation was proved. The study was performed in 7 Sprague-Dawley rats. In order to examine this query two different sonographic contrast media in comparison to agitated electrolyte solution (as the placebo) were injected into the abdominal aorta of 7 anaesthetized rats as a 2 ml/kg bolus at 10-min intervals. Examined were a newly developed agitated ultrasound solution (AK I: an aequeous solution of a vegetable phospholipid) and a radiographic contrast agent (AK II: 741 mg Ioversol or 350 mg iodine, respectively, per ml) which is used in an agitated form as ultrasound contrast agent, too. 1 min before and until 2 min after each injection the capillary perfusion of the same vessel area in the major omentum was measured (video-recording by use of intravital microscopy). The erythrocyte velocity was determined off-line by an image analysing system. Whereas the agitated X-ray contrast medium AK II decreases the mean capillary perfusion (temporary flow stagnation in single capillaries), AK I as well as agitated electrolyte solution did not influence the capillary erythrocyte velocity in the major omentum. The gaps which appeared immediately after the injection of AK I seem to have been brought about by spherosomes of AK I. Still the spherosomes are so small that they can pass through the capillaries, or if they are larger which cannot be determined using in vivo microscopy the flow force necessary for the deformation of the bubbles is so small that the capillary perfusion is not influenced. The injection of agitated AK I does not lead to significant changes of the microcirculation.

Animals↗
PubMed1994

[Comparison of 2 6% middle-molecular hydroxyethyl starch solutions on elimination kinetics and flow characteristics of blood in volunteers].

OBJECTIVE: Investigation of the influence of C2/C6 occupation ratio of 2 different 6% hydroxyethyl starch (HES) solutions on elimination kinetics and blood fluidity. DESIGN: A single-blinded, prospective randomised cross-over study. SETTING: Haemostasiological-angiologic outpatient department of the university of Homburg. SUBJECTS: 6 voluntary apparently healthy subjects. INTERVENTIONS: A 500 ml infusion of 2 different HES solutions (6% HES 200/0.5 or 6% HES 200/0.62, respectively) was given intravenously within 1 h. A wash-out phase of 3 months was kept between both infusions. The concentration and distribution of the molecular weight of the intravasal HES molecules up until 24 h after the infusion as well as the blood fluidity before and after the infusion were measured. RESULTS: Besides the molecular substitution (MS), which is different for the 2 employed HES solutions, the occupation ratio of the C2 respectively C6 (C2/C6 occupation ratio) of the glucose ring influences the breakdown of the HES molecules. This influences the blood fluidity. While the decrease in haematocrit 1 h after the end of the infusion is comparable, the decrease in the haematocrit in the case of high C2/C6 occupation ratio and a high MS is maintained for a longer period of time. The increase in plasma viscosity in the case of high C2/C6 occupation ratio and high MS is more marked. CONCLUSIONS: The infusion of HES 200/0.62 leads to a significantly longer prevalence in comparison to HES 200/0.5, in combination with clearly larger degradation products in the plasma; this fact causes a more marked dilutional effect, but also a more marked increase in the plasma viscosity up to 24 h after the end of infusion. In the discussion on haemodilution therapy in patients with arterial occlusive disease the employment of HES which induces an increase in plasma viscosity is thought to be a disadvantage.

Adult↗
PubMed1993

Effects of garlic coated tablets in peripheral arterial occlusive disease.

For the first time, a weak clinical efficacy of a 12-week therapy with garlic powder (daily dose, 800 mg) is demonstrated in patients with peripheral arterial occlusive disease stage II. The increase in walking distance in the verum group by 46 m (from 161.0 +/- 65.1 to 207.1 +/- 85.0 m) was significantly higher (P < 0.05) than in the placebo group (by 31 m, from 172.0 +/- 60.9 to 203.1 +/- 72.8). Both groups received physical therapy twice a week. The diastolic blood pressure, spontaneous thrombocyte aggregation, plasma viscosity, and cholesterol concentration also decreased significantly. Body weight was maintained. It is quite interesting that the garlic-specific increase in walking distance did not appear to occur until the 5th week of treatment, connected with a simultaneous decrease in spontaneous thrombocyte aggregation. Therefore, garlic may be an appropriate agent especially for the long-term treatment of an incipient intermittent claudication.

Adult↗
PubMed1993

Improved in vitro rheological system for studying the effect of fluid shear stress on cultured cells.

A rheological in vitro system has been developed to study and quantify cellular adhesion under precisely defined external shear forces. The system is similar to a cone-and-plate viscosimeter. A rotating transparent cone produces both steady and pulsatile flow profiles on cultured cells. Direct visualization of cells by phase-contrast or fluorescence optics and connection of the optical system to a computer-controlled x/y-linear stage allows automatic recording of any point of the cell cultures. With the use of up to 12 individual rheological units, this setup allows the quantitative analysis of cell substrate adhesion by determination of cell detachment kinetics. Two examples of application of this rheological system have been studied. First, we show that the extracellular matrix protein laminin strongly increases endothelial cell adhesion under fluid shear stress. In a second approach, we obtained further support for the concept that shear stress-induced formation of actin filament stress fibers is important for endothelial cells to resist the fluid shear stress; inhibition of stress fiber formation by doxorubicin resulted in significant detachment of endothelial cells exposed to medium levels of fluid shear stress (5 dyn/cm2). No detachment was seen under resting conditions.

Animals↗
PubMed1993

[The effect of molecular structure of hydroxyethyl starch on the elimination kinetics and fluidity of blood in human volunteers].

Influence of the Molecular Structure of Hydroxyethyl Starch on Elimination Kinetics and Blood Fluidity in Voluntary Subjects In a cross-over study 6 volunteers received an infusion of 500 ml hydroxyethyl starch of a batch with a high C2/C6-substitution ratio (10.8), or after a washout period of 3 months they received a batch with a low C2/C6-substitution ratio (5.8). The infusion solution was administered at random. The batches were identical as regards their physicochemical characteristics (HES 200/0.5 10%). The concentration and molecular weight distribution of the intravascular hydroxyethyl starch molecules were determined after infusion up to 24 h, the blood fluidity before and after infusion. The substitution ratio of the C2- or C6-atoms in the glucose ring has an effect on the degradation of the hydroxyethyl starch molecule: the molecules with a high C2/C6-substitution ratio appear to be degraded within the same period of time, the resulting degradation products, however, have a higher molecular weight. This influences the blood fluidity. While the haematocrit decrease occurring 1 h after end of infusion is comparable, it keeps up for a longer time in case of a higher C2/C6-substitution ratio. The increase of plasma viscosity is more pronounced in case of a high C2/C6-substitution ratio. Clinical consequences are discussed.

Adult↗
PubMed1992

Capillary occlusion and secondary angiogenesis: case report.

The first follow-up control 5 days later (14.1.1990) showed a fresh capillary occlusion with massive red blood cell diapedesis. The arteriolar limb of the capillary is filled with erythrocytes up to the occlusion. Since capillary occlusion probably allowed some plasma flow at first, blood cells distal to the occlusion were washed away. After 53 days (8.3.1990) extravasal cells could no longer be made out. At the upper margin of the image a newly formed capillary loop can be seen. The channel of the old capillary seemed to have disappeared. Seventy-three days after occlusion, on 28th of March, the tip of the capillary, already demonstrated on 8th of March, had further grown distally. The capillary had crossed the neighbouring diagonal capillary. Twelve days later (9.4.1990) a remarkable growth connected with formation of a collateral was observed. The new capillary grew in direction of the former capillary channel. On 22nd of April the new capillary had almost got back to its old form. The collateral vessel formed on 9th of April had also grown and could be well distinguished. The different branches were immediately well perfused (mean erythrocyte velocity is v = 0.74 mm/s). The capillary were growing at different speeds. The new capillary had visibly grown by 220 microns over a period of 47 days which corresponds to an average growth of 4.7 microns a day. The capillary was growing fastest between the 9th and 22nd of April. A minimum of growth of 2 microns was observed within the first 11 days of the observation period.

Adult↗
PubMed1992

Hemorrheological and circulatory effects of Gincosan.

Gincosan is a combined preparation containing 60 mg ginkgo biloba and 100 mg ginseng, standardized of 24% ginkgo flavone glycosides and 4% ginsenosides. Hemorrheological and circulatory effect as well as blood pressure behavior after the administration of gincosan were studied in an acute trial on 10 voluntary subjects with a mean age of 26 years. Systolic blood pressure decreased significantly both for the large-dose (120 mg ginkgo biloba +200 mg ginseng) and low-dose administration (60 mg ginkgo biloba +100 mg ginseng). Diastolic blood pressure and heart rate decreased only in the high dosage group. The pathologically increased spontaneous platelet aggregation is reduced by both dosages. Erythrocyte velocity in nail fold capillaries increased significantly only in the high dosage group. The parallel group comparison of the high dosage and placebo group showed that they differ only significantly concerning the erythrocyte rigidity, erythrocyte velocity in nail fold capillaries and spontaneous platelet aggregation. A trend towards a decrease in the systolic blood pressure is revealed (p less than 0.1).

Adult↗
PubMed1991

Influence of garlic powder on cutaneous microcirculation. A randomized placebo-controlled double-blind cross-over study in apparently healthy subjects.

In a randomized placebo-controlled double-blind cross-over study it could be shown that 5 h after the administration of garlic powder (Kwai, Sapec; total dose of 900 mg garlic powder) a significant increase in capillary skin perfusion by 55% occurs in the healthy volunteers. Placebo did not cause any changes. The difference between the two study phases is also significant. The increased erythrocyte velocity results from vasodilation of precapillary arterioles which increases diameter of erythrocyte column by an average of 8.6%. Simultaneously inflow of interstitial fluidity accompanied by a significant decrease in haematocrit and plasma viscosity occurs (rheoregulation).

Adult↗
PubMed1991

Effect of garlic on thrombocyte aggregation, microcirculation, and other risk factors.

Significant positive effects could be achieved in a placebo-controlled double-blind study through the administration of 800 mg of garlic powder over a period of four weeks. Spontaneous thrombocyte aggregation disappeared, the microcirculation of the skin increased by 47.6% (from 0.63 +/- 0.13 to 0.93 +/- 0.22 mm/s), plasma viscosity decreased by 3.2% (from 1.25 +/- 0.34 to 1.21 +/- 0.43 mPas), diastolic blood pressure by 9.5% (from 74 +/- 9 to 67 +/- 5 mmHg), and blood glucose concentration by 11.6% (from 89.4 +/- 8.8 to 79.0 +/- 11.9 mg/dl). The vascular protection of garlic as atherosclerosis prevention by influencing the mentioned risk parameters for cardiovascular diseases must be pointed out. Especially interesting is the thrombocyte aggregation inhibiting effect. Thus, the application of garlic may be useful in case of acetylsalicyclic acid intolerance.

Adult↗
PubMed1990

[Error analysis, biological modification factors and variance of peri-ungual video-capillary microscopy].

Error analysis or the evaluation of the precision of microscopic measurements must distinguish between technical errors inherent in the measuring system, and biological variability. The technical error inherent in the overall system in the case of linear measurements is smaller than the lengths to be measured by 1 or 2 orders of magnitude. Thus, the erythrocyte column lengths can be correctly, reproducibly and linearly quantified over the entire measuring range. The biological influencing factors can largely be taken into account or excluded by suitable standardisation of the measuring process. Despite a considerable individual fluctuation in the erythrocyte velocity, there is, on average, no significant dependence of the measuring parameter within the daily profile or from day to day. Differences in capillary perfusion in the presence of diseases associated with microcirculatory disorders or a therapeutic influence on erythrocyte velocity can thus be reliably demonstrated.

Capillaries↗
PubMed1990

[Effect of hemodilution on systemic and capillary hematocrit].

In a cross-over study including 10 clinically healthy male volunteers, the hematocrit in the macro- and microcirculation was investigated prior to and 1 h, 3 h, 6 h and 24 h after iso- or (3 months later) hypervolemic hemodilution using 500 ml hydroxyethyl starch. The dilution effect observed after isovolemic hemodilution is more pronounced than after hypervolemic hemodilution. While isovolaemic hemodilution with 500 ml medium molecular weight hydroxyethyl starch leads to a reduction in the systemic hematocrit by 8.5% by volume, the capillary hematocrit at the time of the most marked dilution (1 h after hemodilution) decreases by only 1.3 hematocrit points in the cutaneous capillaries. After hypervolemic hemodilution, the systemic hematocrit decreases significantly by maximally 5.4% by volume, while the capillary hematocrit does not change significantly.

Adult↗