Impaired microvascular reactivity and endothelial function in patients with Cushing's syndrome: influence of arterial hypertension

The aim of the study was to evaluate skin microvascular reactivity (MVR) and possible influencing factors (fibrinolysis, oxidative stress, and endothelial function) in patients with Cushing's syndrome. Twenty-nine patients with active Cushing's syndrome (ten of them also examined after a successful operation) and 16 control subjects were studied. Skin MVR was measured by laser Doppler flowmetry during post-occlusive (PORH) and thermal hyperemia (TH). Malondialdehyde and Cu,Zn-superoxide dismutase were used as markers of oxidative stress. Fibrinolysis was estimated by tissue plasminogen activator (tPA) and its inhibitor (PAI-1). N-acetyl-beta-glucosaminidase, E-selectin, P-selectin, and ICAM-1 were used as markers of endothelial function. Oxidative stress and endothelial dysfunction was present in patients with hypercortisolism, however, increased concentration of ICAM-1 was also found in patients after the operation as compared to controls (290.8+/-74.2 vs. 210.9+/-56.3 ng.ml(-1), p<0.05). Maximal perfusion was significantly lower in patients with arterial hypertension during PORH and TH (36.3+/-13.0 vs. 63.3+/-32.4 PU, p<0.01, and 90.4+/-36.6 vs. 159.2+/-95.3 PU, p<0.05, respectively) and similarly the velocity of perfusion increase during PORH and TH was lower (3.2+/-1.5 vs. 5.2+/-3.4 PU.s(-1), p<0.05, and 0.95+/-0.6 vs. 1.8+/-1.1 PU.s(-1), p<0.05, respectively). The most pronounced impairment of microvascular reactivity was present in patients with combination of arterial hypertension and diabetes mellitus.     

Modeling of arterial stenosis and its applications to blood diseases

Blood flow in a stenosed tube has been modeled in the present studies. Blood flow is assumed to be represented by a couple stress fluid. Flow parameters such as velocity, resistance to flow, and shear stress distribution have been computed for different suspension concentrations (haematocrit), and for the blood diseases; polycythemia, plasma cell dyscrasias, and for Hb SS (sickle cell). The results have been compared with the case of normal blood and for other theoretical models. The importance of size effects in blood flow studies has been highlighted.     

Function and reactivity of the microvascular bed in human neuroses

By contact microscopy the state and reactivity of the capillary bed (capillaries of the cheek mucosa) were studied in neurotic patients with different levels of arterial pressure (AP). It has been shown that at constant AP capillariscopic parameters (diameter, length and number of capillaries in the visual field) are relatively stable. Neuroses with hypertension are characterized by uneven (more expressed in arterioles) contraction of the capillaries, accelerated development and greater duration of reactions to the mental stress and applications of adrenaline and noradrenaline solutions in comparison with healthy persons. In hypotension, uniform capillaries contraction and slower development of the above reactions are observed.     

Rice policosanol does not have any effects on blood coagulation factors in hypercholesterolemic patients

Policosanol is an agent that includes mixtures of aliphatic primary alcohols extracted primarily from sugercane wax. Policosanol has been shown to lower total and LDL cholesterol in animal models, healthy volunteers and hypercholesterolemic patients. However, these findings have been challanged recently. Up to now, there has been no study investigating the effects ofpolicosanol on blood coagulation factors. This study investigated the effects of rice policosanol (Oryza sp.) 10 mg/day on blood coagulation factors in 66 hypercholesterolemic patients of both sexes aged 20 to 78 years in a single center, randomized, double-blind, placebo-controlled, crossover trial. After an 8-week run-in period in which patients were placed on therapeutic lifestyle changes, in particular a cholesterol-lowering diet, they were randomly assigned to receive rice policosanol 10 mg tablets or placebo tablets once daily with the evening meal for 8 weeks. During next 8 weeks those receiving policosanol during the first 8 weeks, received placebo and those taking placebo during the first 8 weeks, received policosanol. Plasma fibrinogen, factors VII, VIII, XII and XIII were measured before and after the treatment. Rice policosanol treatment did not change significantly neither fibrinogen nor factors VII, VIII, XII and XIII.     

Serotonin metabolism in thrombocytes and microvascular hemostasis in spontaneous arterial hypertension

Serotonin content and accumulation in platelets and its release from them, as well as changes in thrombus formation in mesenteric arterioles and venules of the small intestine have been investigated in control rats and rats with spontaneous hypertension (SHR). Serotonin accumulation in platelets was determined upon its incubation with platelets. Disodium ADP salt was used as an inductor of release. Laser-induced thrombosis was caused by microvessels exposure to impulse laser irradiation. The control animals revealed a significant difference between the initial serotonin platelet level and serotonin level upon incubation and release; in values, the values of basic thrombus-forming parameters were higher than in arterioles. In SHR there is a decrease in biogenic amine content in platelets, a depression in its accumulation and release, an increase in the time of thrombus growth, its size up to the separation of the first embolus and its length along the vascular wall. It is concluded that spontaneous hypertension is characterized by decreased functional activity of platelets and depressed resistance of arterioles and venules to thrombus formation.     

Direct coronary arterial stenting without predilatation in patients with coronary heart disease

The study was undertaken to evaluate the safety and efficiency of direct stenting versus routine stenting with predilation. It included 133 patients. By the decision of operators, direct stenting was conducted in 66 patients (71 stenoses) (Group 1). The remaining 67 patients (73 stenoses) underwent routine stenting with predilation (Group 2). The initial angiographic success of stenting was 100% in Group 1 and 98 in Group 2. Complications were absent. In the direct stenting group, technical problems occurred during a session in 9 (12%) cases. In this group the mean duration of fluoroscopy and the total duration of a session were much less than in the routine stenting group. The mean number of balloons used at dilation per stenosis and the number of dilation sessions per stenosis were much lower in Group 1 than in Group 2. The results of quantitative angiogram analysis before and after a session were similar in both patient groups. Six months following stenting, angiographic restenosis occurred in 7 (10%) patients in Group 1 and in 9 (12%) in Group 2. Direct stenting is a safe and effective treatment for non-occlusive coronary lesions without marked kinks and calcinosis. Direct stenting reduces the duration of fluoroscopy and the total duration of an operation by 50 and 22%, respectively, as compared to predilation stenting.     

A study of non-Newtonian aspects of blood flow through stenosed arteries and its applications in arterial diseases

Blood flow through a stenosed artery has been investigated in this paper. Blood has been represented by a non-Newtonian fluid obeying Herschel-Bulkley equation. This model has been used to study the influence of the fluid behaviour index n, shear-dependent nonlinear viscosity K and the yield stress tau H in blood flow through stenosed arteries. The variation of the wall shear stress and the flow resistance with n, K and tau H has been shown graphically. It is observed that the wall shear stress and the flow resistance increase in Herschel-Bulkley fluid in comparison with corresponding Newtonian fluid. It is of interest to note that, in the present model, the thickness of the plug core varies with the axial distance z in the stenotic region. Finally, some biological implications of the present model for some arterial diseases have been briefly discussed.     

Separation of blood cells from normal blood and blood of patients with various malignant blood diseases using separation media

Differential counts of normal and leukemic cells separated from human peripheral blood were compared using three different separation media a) Verografin, b) Verografin-Ficoll, c) Isopaque-Ficoll (Lymphoprep), density 1.077 g/ml. In the separation the solution of Verografin (SPOFA) or Verografin-Ficoll yields analogous cell counts to Isopaque-Ficoll solution. The separation of leukemic cells is similar on all three separation media with considerable packing of some cells of the myeloid line. The blood cells separated from peripheral blood of normal donors on three various separation media correlate also in T and B lymphocyte counts, as demonstrated by the results of E and EAC rosette tests.