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Biomedical subjects

E Wenzel

Publications and source records attributed to E Wenzel.

At least 91 records · Page 5Linked to original sources

[Subcutaneous injection of desmopressin (DDAVP) for increasing factor VIII and von Willebrand factor in plasmapheresis].

Desmopressin (DDAVP) is an effective tool for increasing factor VIII (FVIII)/von Willebrand factor (vWF) in normal subjects and in patients with haemophilia A and von Willebrand's disease. There are a few studies utilizing DDAVP to increase the FVIII/vWF yield in plasmapheresis donors. In these studies, DDAVP was given either by intranasal administration or intravenous infusion. The aim of our pilot study was to investigate the subcutaneous (s.c.) injection of DDAVP in combination with double bag plasmapheresis. 8 donors with blood group A and 5 with O were given 0.4 micrograms/kg body weight DDAVP as a s.c. injection 30 min prior to the first donation. FVIII increased 3.7 and ristocetin cofactor 2.5 the initial value in the donors. In the plasma bags, a 3 (1st bag) and 3.5 (2nd bag) fold higher FVIII level was found, when compared with baseline levels. There was only a mild decrease of blood pressure, and serious adverse effects were not observed. Our data suggest that s.c. DDAVP may be more effective and especially suited for increasing FVIII/vWF yield in plasmapheresis donors.

Blood Donors↗

[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↗

[Pharmacologic and clinical principles for rational anti-thrombotic preventive treatment with low molecular weight heparin].

Heparin exerts its anticoagulant function by accelerating the inhibitory effect of antithrombin III. Low molecular weight heparin (LMWH), which is derived from unfractionated heparin (UFH), exhibits marked anti-Xa activity and minor thrombin inhibition. It has an elevated bioavailability and longer half-life as to the anti-Xa clearance when compared to UFH. Platelet, endothelial and fibrinolytic effects are also involved in antithrombotic action. Clinical trials have shown that LMWH compared to UFH is an equivalent and even advantageous method of antithrombotic prophylaxis in surgical patients and has also a minor risk of bleeding.

Blood Coagulation Tests↗

Effects of garlic on blood fluidity and fibrinolytic activity: a randomised, placebo-controlled, double-blind study.

In summary, it can be said that the improvement of blood fluidity and the simultaneous increase in fibrinolytic activity are an ideal complement. While the increase in fibrinolytic activity supports the physiological reparation process in the microcirculation, the improvement of blood fluidity produces an increase in capillary perfusion that has, in some way, a cleaning effect, with a 'purification' of the microcirculation.

Adult↗

Effect of Ginkgo biloba on fluidity of blood and peripheral microcirculation in volunteers.

In a randomized placebo controlled single-blind cross-over study of n = 10 apparently healthy subjects the influence of Ginkgo biloba (Kaveri) on blood fluidity and cutaneous microcirculation was studied. Microcirculation was measured before and every 30 min for 4 h after administration of Ginkgo biloba; fluidity of blood was determined before and after 1, 2 and 4 h. Significant changes in blood pressure or heart rate were found neither during Ginkgo phase nor placebo phase. Haematocrit, plasma viscosity, erythrocyte rigidity, thrombocyte and leukocyte count as well as thrombocyte aggregation and the number of circulating thrombocyte aggregates were also not influenced by the Ginkgo nor the placebo solution. In contrast a remarkable influence on the erythrocyte aggregation was observed: comparing two samples a significant decrease by 15.6% (p less than 0.001) with regard to the initial value was observed after 2 h. The blood flow in the nail fold capillaries also increased significantly by about 57% (p less than 0.004) 1 h after administration.

Adult↗

[Hemodilution in patients with multiple morbidity and peripheral arterial occlusive disease].

The treatment of multi-morbid patients suffering from peripheral arterial occlusive disease (PAOD) is rendered difficult due to concomitant diseases such as coronary heart disease, chronic obstructive pulmonary affection, arterial hypertension or diabetes mellitus. Haemodilution can be a clinically efficient therapy for some of the concomitant diseases as well. It is, however, necessary to use a weak colloidal solution which has no additional volume effect as an iso-oncotic substance. Hydroxyethyl starch 200/0.5 6% meets all these demands. In a double-blind, placebo-controlled study over a period of 6 weeks a marked and significant increase of almost 40% in painfree walking distance was achieved for 19 of 37 multi-morbid patients with PAOD II by moderate hypervolaemic haemodilution with venesections. Besides the clinical improvement, blood fluidity also increased through a reduction in haematocrit, plasma viscosity, and erythrocyte aggregation.

Adult↗

[Iso- and hypervolemic hemodilution with hydroxyethyl starch (HES 200/.05 10%) in patients with II b peripheral arterial occlusive disease].

The basic therapy in stage IIb of peripheral arterial occlusive disease (PAOD) according to Fontaine is exercise. The aim of this study was to test whether (given initial physiological hematocrit values of 43 to 46%) a mild hypervolemic to isovolemic to hematocrit values of 40% with HES 200/0.5 10% or Ringer lactate in combination with exercise is even more favorable. In order to answer this question, 3 groups of 25 patients each were formed. One group exercised three times weekly and the second group, in addition to exercise, underwent a mild, hypervolemic to isovolemic 6-week dilution therapy with HES. In the final group the hematocrit value was reduced to the same extent by means of venesection and volume substitution with Ringer lactate. The walking distance increased in the HES group from 216 to 311 m (44%), in the Ringer lactate group from 214 to 258 m (20%), and in the exercise group from 213 to 242 m (14%). In comparison of the groups, the increase in pain-free walking distances in the HES group is found to differ significantly from those in the other groups. It was clearly demonstrated that hemodilution with HES in combination with exercise brings about a clinical effect of an order three times of that achieved by exercise alone. Venesection with subsequent administration of Ringer lactate and exercise is superior to exercise alone, but is markedly inferior to the combination therapy with HES.

Adult↗

Effects of fish oil capsules in two dosages on blood pressure, platelet functions, haemorheological and clinical chemistry parameters in apparently healthy subjects.

The effects of a fish oil concentrate with an omega-3 fatty acid content of 42% was determined in two dosages in a double-blind, placebo-controlled study with a parallel group comparison over a period of 5 weeks with 30 healthy subjects. The daily intake chosen was four and eight capsules corresponding to 1.26 or 2.52 g omega-3 fatty acids. Plasma viscosity, erythrocyte rigidity and systolic blood pressure were significantly decreased (p less than 0.01) after a 5-week administration of 2.52 g omega-3 fatty acid daily. The reduction in vitamin E concentration was significant (p less than 0.01) only in the low-dose fish oil group. Lipids and lipoproteins remained unchanged throughout this experiment.

Adult↗

Subcutaneous injection of desmopressin (DDAVP): evaluation of a new, more concentrated preparation.

A more concentrated desmopressin (DDAVP) preparation (40 micrograms/ml), which required small injection volumes (less than 1 ml), was studied in a double-blind trial in 10 healthy volunteers, 12 patients with haemophilia A, and 8 patients with uraemic bleeding. DDAVP was administered by subcutaneous injection at a dose of 0.4 micrograms/kg body weight. In healthy subjects, peak levels of DDAVP ranging from 480 to 638 pg/ml were reached 1 h after the subcutaneous injection and DDAVP was eliminated with a mean half-life of 3.1 h. DDAVP produced a 2.5-fold (3.0-fold) increase of factor VIII:C (factor VIII:Ag) and a 1.9-fold (2.2-fold) increase of von Willebrand factor:Ag (ristocetin cofactor) over baseline levels. Additionally, a 2.1-fold increase of tissue-type plasminogen activator antigen was observed. Factor VIII and von Willebrand factor were rapidly eliminated with a half-life ranging from 1.3 to 5.7 h and from 1.1 to 11.4 h, respectively. In haemophilia A patients, DDAVP produced a 2.3-fold increase of factor VIII:C 1 h after the injection. DDAVP was given on 8 occasions for management of bleeding, and only in 1 patient did a wound haematoma (after herniotomia) occur. In 7 of the 8 patients with uraemia the bleeding time shortened, and in all patients an increase of platelet retention and a decrease of platelet count was observed (p less than 0.05). No serious local or systemic untoward side effects were observed.

Adult↗

[Hemorheologic, micro- and macrocirculatory effects of an infusion of 500 ml of 6% medium molecular weight hydroxyethyl starch (Haes 200,000/0.5)].

In an open study the influence of hypervolemic hemodilution (Infusion of 500 cc hydroxyethyl starch 200,000/0.5 6% within 1 h) on macro- and microcirculation, fluidity of blood and conjunctival oxygen tension was investigated. Blood pressure and heart rate remained unchanged during and after the infusion. One hour after the infusion there was a tendency towards an increase in blood flow in the common carotid artery which then returned to normal again. The capillary circulation as well as the conjunctival oxygen partial pressure were significantly increased after 3 h. This correlated well with the decrease in plasma viscosity and erythrocyte aggregation. The effect of hemodilution using 6% middle molecular weight hydroxyethyl starch with a substitution degree of 50% on microcirculation was probably due to the rheological and not to the hemodynamic effect.

Adult↗

Study of a new low molecular weight heparin (LU 47311) administered to healthy volunteers.

A newly developed low molecular weight heparin (LU 47311) was given to 6 healthy volunteers (males, mean age: 30.5 years, range: 20-39 years). They obtained a single dose of 40 and 60 anti FXaU per kg body weight, respectively, by subcutaneous administration. The anti FXa elimination half-life was close to 3 hours. The APTT showed slight response following high dose. No significant influence on fibrinolysis as measured by t-PA and PAI assays was noticed. There was no clear evidence of enhancement of platelet function when detected by Born's method and platelet factor 4 and beta-thromboglobulin assays. However, a moderate but significant increase of thromboxane B2 was noticed in the group obtaining an elevated dose of LMW heparin. Serum levels of triglycerides and cholesterol remained unaltered. The aminotransferases, electrolytes, renal function parameters and cell counts of the peripheral blood were not influenced by LMW heparin.

6-Ketoprostaglandin F1 alpha↗

[Bag plasmapheresis in patients with stage IIb peripheral arterial occlusive disease].

The clinical effect of bag-plasmapheresis was investigated in 60 patients with peripheral arterial occlusive disease stage II according to Fontaine. The initial number of patients was subdivided in three groups of 20 individuals using a randomised double-blind placebo-controlled design. Each patient gave 300 ml of blood twice a week for a 6 week duration. Blood plasma was separated in two groups and replaced with Hydroxyethyl-starch (200/0.5 10%) in group 1 and with Laevulose 5% in group 2. Patients in group 3 received their whole blood without any processing. All patients had to undergo a physical training of 45 minutes three times a week. The group who received Hydroxyethylstarch presented a 20% increase in walking distance whereas the increase in the Laevulose group was 5% and approximately 1% in the group receiving whole blood. The increase in walking distance in the Hydroxyethylstarch-group was significant on the 0.1%-level and significantly better than the improvement in walking distance of the other groups. Additionally in this group plasma viscosity showed a 3% decrease, erythrocyte aggregation was reduced by 10%. Results in the Laevulose group were only half as good as in the Hydroxyethylstarch group while parameters remained unchanged in the whole-blood-group. Bag plasmapheresis with Hydroxyethylstarch as substitute leads to an improvement in the walking capacity and blood fluidity thus offering a promising therapy for peripheral vascular occlusive disease.

Adult↗