Thrombozytenagglutination und Gefäßkrankheiten

Qualitative analysis of modified advanced-platelet-rich fibrin buffy coat among diabetic patients and tobacco smokers with chronic periodontitis: A cell block cytology study

Aim:

The aim of this study was to evaluate and compare histologically the pattern of distribution of platelet and leukocyte concentration, quality of fibrin network, and the aggregation of platelets in the three zones of modified advanced platelet-rich fibrin (A-PRF) buffy coat among uncontrolled type 2 diabetic patients, tobacco smokers, and healthy individuals with chronic periodontitis.

Materials and Methods:

In this cross-sectional cytology study, 180 generalized chronic periodontitis patients (46–55 years) were enrolled – Group 1 (control group): 60 systemically healthy participants, Group 2 (test group): 60 heavy tobacco smokers, and Group 3 (test group): 60 uncontrolled type 2 diabetic patients. Fifteen milliliters of blood was drawn from all study participants. Modified A- PRF membrane was prepared and then processed histologically.

Results:

The distribution pattern of platelet and leukocyte concentration in modified (A-PRF) gradually declines from the serum to the red blood cell (RBC) end of a clot in all groups. We have assessed that the serum and middle end of modified (A-PRF) membrane had an increasingly moderate distribution of platelets and leukocytes in both type 2 diabetics and tobacco smokers. RBC end had more of sparse distribution in all the three groups. Healthy individuals exhibited 95% of reversible pattern, whereas tobacco smokers had 78.33% and uncontrolled type 2 diabetic patients had 93.33% of irreversible aggregation pattern of platelets. Loose fibrin network pattern was seen in all the three groups. These observations conclude that tobacco smokers had a high percentage of loose fibrin network with sparse distribution of cells. Males showed more loose fibrin network pattern of modified (A-PRF) membrane than compared to females.

Conclusion:

In the present study, it can be concluded that the application of modified (A-PRF) may provide enhanced periodontal healing in uncontrolled type 2 diabetic patients and tobacco smokers; furthermore, females may have better regenerative capacity compared to males.

Transdermal estradiol substitution therapy for the induction of puberty in female hypogonadism

Fifteen patients aged 14.5-27.3 years (mean +/- SE 18.8 +/- 0.9) with pubertal development failure underwent replacement therapy with estradiol (E2) using a transdermal therapeutic system (TTS). Fourteen of them were affected by hypogonadotropic hypogonadism (11 with thalassemia major, 3 with multiple pituitary hormone deficiency), the 15th patient had an asymmetric gonadal dysgenesis (karyotype 45, X 0/46, XY). Two sizes (5 and 10 cm2) of E2 TTS, delivering respectively 25 and 50 micrograms of E2 a day for 3 1/2 days, were used in this study. All patients were initially given the lower dose of 25 micrograms, twice weekly for 3 weeks each month; 6 months after starting therapy, 5-10 mg oral medroxyprogesterone acetate (MPA) daily was added during the third week. Later, the following sequence was used: 25 micrograms E2 TTS (twice weekly), on days 1 through 14, and 50 micrograms E2 TTS (twice weekly), on days 15 through 25 of each month. On days 15 through 25, 5 mg daily of MPA were administered orally. The period of treatment ranged from 0.5 to 3 years. Breast development was obtained in all cases. The vaginal maturation index rose. Ultrasonography showed an increase of uterine size and uterine shape became of pubertal type. Withdrawal bleeding occurred in all patients. Plasma E2 levels rose to normal levels, estrone (E1) levels increased slightly. No change in plasma SHBG levels was observed. Urinary E2, E1 and estriol rose to maximum levels the 3rd day after the application of each system. Neither systemic side effects nor adverse metabolic effects were observed except for an increased sensitivity to the platelet aggregating agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes of spontaneous and induced platelet aggregation in the presence of a human endothelial cell monolayer

A new, simple method has been developed for the investigation of platelet aggregation in the presence of a cultured confluent human endothelial cell monolayer, in disk shaped rotating cuvettes, without magnetic stirring. The endothelial cells inhibited the aggregating effect of several inducers in a concentration dependent manner. At a platelet count of 5 x 10(5)/microliter in PRP e.g. the aggregating effect of 1 microgram/microliter thrombin was completely abolished. Spontaneous aggregation was also prevented by the EC-monolayer. A correlation could be established between the inhibitory effect of ECs and the number of platelets. In PRP with a platelet count of 7 x 10(-5)/microliters the inhibitory effect of the endothelial cell monolayer significantly decreased.

Quantified EEG, somatosensory evoked potentials and cerebral blood flow in monitoring experimental brain ischemia

Cerebral ischemic lesions were induced in rabbits through internal carotid artery embolization by means of microspheres. Different models of stroke ranging from single focal cortical lesion to massive bilateral brain edema were reproduced and monitored up to the 24th hour by electroencephalogram (EEG and QEEG), somatosensory evoked potentials (SEPs), cerebral blood flow (CBF), platelet aggregation. The site and extent of the lesions were verified by histological examinations. Results obtained and physiopathological implications are discussed.

The influence of combined treatment with propranolol and acetylsalicylic acid on platelet aggregation in coronary heart disease

1 Antiaggregating agents are frequently prescribed alone or together with β-adrenergic receptor blocking agents in patients after myocardial infarction. The present study was designed to examine the effects of combined treatment with propranolol and acetylsalicylic acid (ASA) on platelet aggregability.

2 Spontaneous platelet aggregation and aggregation induced by fibrinogen and adrenaline were studied in a group of patients with coronary heart disease before treatment, after treatment with propranolol (0.75-1.0 mg/kg daily), and after combined treatment with propranolol in same dose and ASA (20-25 mg/kg daily). Twenty-one patients with stable angina pectoris and/or after myocardial infarction and twelve healthy men were included in the study.

3 There were no significant differences in both spontaneous and induced platelet aggregation between patient and control group before treatment. Propranolol influenced fibrinogen-induced aggregation: it lowered maximal amplitude of aggregation (P < 0.05), but it did not change the reaction time. ASA in combination with propranolol affected both spontaneous and induced aggregation: it diminished the number of pathological spontaneous aggregations (P < 0.025), it inhibited the second wave of adrenaline-induced aggregation (P < 0.01), prolonged the reaction time of fibrinogen-induced aggregation (P < 0.01) and lowered the maximal amplitude of aggregation (P < 0.05).

4 The study showed that propranolol besides its well-known hemodynamic effects had an additional antiaggregating property. The action of combined treatment with propranolol and ASA on platelet aggregation is probably additive.

[Coagulation and fibrinolytic system in the vascular risks diabetes mellitus and hyperlipoproteinemia (author's transl)]

42 patients with minifest diabetes mellitus and 42 patients with primary hyperlipoproteinemia type II, IV or V (Fredickson) underwent analysis of cholesterol, triglycerides and agar-agarosegel-lipoprotein electrophoresis. Simultaneously clotting factors I--XIII, platelet count and aggregability, fibrinolytic activity and antithrombins were determined. The most accentuated disturbances were seen in hyperlipoproteinemia type II and in diabetes mellitus comprising increase of fibrinogen content, platelet reduction and enhanced platelet aggregability, hypofibrinolysis. Only minor differences of certain clotting factors could be detected comparing diabetes mellitus and hyperlipoproteinemia type II. Diabetes mellitus being complicated by micro- or macroangiopathia revealed additional significant alterations such as more pronounced increase of fibrinogen, further platelet reduction and aggregability. Increase of fibrinogen, platelt disturbances, hypofibrinolysis and alterations of antithrombin activity in connection with metabolic diseases may be regarded as additional risk to vascular complications.

Effects of acute myocardial ischaemia on platelet aggregation in the coronary sinus and aorta in dogs

The effect of an acute myocardial ischaemia on circulating platelet aggregates (CPA) in the coronary sinus and aorta was studied in open chest dogs. Even before induction of myocardial ischaemia significantly more CPA were found in the coronary sinus than in the aorta. Acute myocardial ischaemia produced by a non-thrombotic coronary artery occlusion increased CPA in coronary sinus, but not in aorta. Administration of acetylsalicylic acid (ASA) reduced the extent of the myocardial ischaemia as evidenced by reduced ST-segment elevations in epicardial ECG. Before induction of myocardial ischaemia, ASA significantly reduced CPA in coronary sinus, but no significant effect was observed during myocardial ischaemia. In the aorta no effect of ASA on CPA was found.

Alterations of clotting factors and platelets during hemofiltration

The influence of hemofiltration on the number of platelets and on coagulation factors was investigated in patients with chronic renal insufficiency. These investigations were done on 12 patients during 22 treatments with hemofiltration. Blood samples were taken before hemofiltration, 10, 30 and 120 minutes after the beginning of the treatment and at the end of hemofiltration. In comparison to the original values we found a loss of platelets, a small decrease in the concentration of fibrinogen and a small increase in the fibrin monomer complex, plasminogen, antithrombin III, alpha1-antitrypsin and in alpha2-macroglobulin. The thrombin time, the partial thromboplastin time and Quick's test showed that the blood of these patients contained sufficient hepatin. Use of fibrin plates (Astrup) showed no signs of fibrinolytic activity. Compared to the results, which were obtained some years ago during hemodialysis, we found a smaller extent of alterations of blood coagulation factors and number of platelets.

Platelet function and plasma free fatty acids during acute myocardial infarction and severe angina pectoris

The relationship between platelet function and plasma free fatty acid concentration has been studied serially during the initial 24 h in 11 patients suffering from acute myocardial infarction and in 5 patients with severe angina pectoris, Similar results were obtained in the 2 groups. Plasma free fatty acid concentration was initially high, and decreased significantly. The distribution of plasma free fatty acids remained unchanged. Platelet concentration was constant, whereas the percentage of reversible venous platelet aggregates initially was higher than in 11 healthy persons matched for age and sex. Platelet aggregates decreased transiently at 16 h. Venous reversible platelet aggregates correlated significantly with concentration of plasma free fatty acid, thus establishing a possible link between a change in lipid metabolism and platelet function. Plasma concentration of platelet factor 4 increased slightly but significantly during the initial hours. This may indicate an increased platelet release reaction.

Inhibition of platelet aggregation caused by estrogen treatment in patients with carcinoma of the prostate

Platelet aggregation is increased in patients with carcinoma of the prostate treated with estrogens. Hence, these patients have a high incidence of cardiovascular and thromboembolic diseases. Platelet aggregation has been tested with the platelet aggregation test. It was inhibited by administration of 500 mg. acetylsalicylic acid twice daily. An aggregation inhibiting effect has been found in all 38 patients. To reduce the excess hazards of cardiovascular complications of estrogens in treating carcinoma of the prostate acetylsalicylic acid is recommended as an adjunct therapy.

[Frequently recurring cyclic megakaryocytopenic-thrombopenic purpura]

An unusual case of acquired frequently remitting megakaryocytopenic-thrombocytopenic purpura in a 54 years old man is reported. The patient could be followed up anamnestically for 11 years. Regularly megakaryocytopenic-thrombocytopenic periods were followed by complete remissions. Platelet survival was normal in thrombocytopenic and in remission phases. No immune mechanism could be detected. The exceptional position of this disorder within the inhomogenous group of intermittent thrombocytopenic purpuras is discussed, and the common criteria with three other published cases are pointed out.

[Measurement of spontaneous platelet aggregation. Platelet aggregation test III (author's transl)]

A new measuring device for the estimation of the "spontaneous" aggregating activity of thrombocytes has been developed. In this photometric platelet aggregation test (PAT III) a small amount (0.6 ml) of platelet-rich plasma (PRP) is being rotated in a disc-shaped cuvette at 20 rpm, at 37% C. Changes in optical density of PRP which are induced by the formation of platelet aggregates are continuously registered using a chart recorder. The decisive trigger mechanism for aggregation is an increase of plasma pH in the rotating sample which is caused by evaporation of CO2. The results of the test depend on the platelet count in PRP. Aggregation curves are misrepresented by admixture of erythrocytes and lipid turbidity. The tendency of platelets to aggregate increases within 60-90 min following blood sampling. During this period the time interval to the onset of aggregation(Tr) is shortening, and the maximum aggregation speed (alpha2) is increasing. The spontaneously enhanced aggregation tendency of thrombocytes may be reliably measured from 60 min after drawing the blood. The reason for these time-dependent changes which are also demonstrable in ADP-collagen-or epinephrine-induced aggregation is probably the primary shape change of platelets, which occurs after blood drawing and makes them "stickly" and aggregable. PAT III was developed for the detection of enhanced platelet aggregation, indicating a risk of thrombosis and thromboembolic omplications. The new measuring device has been designed as "universal" aggregometer. Additional equipment is available for the registration of ADP-collagen-or epinephrine-induced aggregation similar to Born's and O'Brien's methods. The device may be mounted easily on an Eppendorf photometer without further modifications.