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Biomedical subjects

E Minar

Publications and source records attributed to E Minar.

At least 109 records · Page 6Linked to original sources

Effect of lovastatin on hemorheology in type II hyperlipoproteinemia.

To assess the effect of lovastatin on blood rheology, the hemorheological determinants fibrinogen, red cell aggregation, plasma viscosity, hematocrit and platelet aggregation (spontaneous and ADP-induced) were studied in 15 patients with type II hyperlipoproteinemia in the course of treatment with lovastatin. Prior to therapy, fibrinogen (Fgen), red cell aggregation (RCA-S, RCA-L) and plasma viscosity (PV) as well as cholesterol (Chol) and triglycerides (Tg) were increased in the hyperlipemic patients compared with healthy normolipemic controls (Fgen: 319.3 +/- 65 vs. 269.8 +/- 48 mg/dl; RCA-S: 7.93 +/- 1 vs. 6.62 +/- 1, RCA-L: 9.86 +/- 1 vs. 7.8 +/- 1 arbitrary units; PV: 1.75 vs. 1.63 mPa/s; Chol: 317.0 +/- 32 vs. 176.5 +/- 21 mg/dl; Tg: 154.5 +/- 88 vs. 72.8 +/- 16 mg/dl; all P less than 0.05). Three months of treatment with lovastatin resulted in a marked decrease in red cell aggregation and plasma viscosity, parallel to a fall in cholesterol (the following pretreatment values were monitored after a standard lipid-lowering diet; RCA-S: 7.59 +/- 1 vs. 6.65 +/- 0.9, RCA-L: 9.34 +/- 1 vs. 8.15 +/- 1 arbitrary units; PV: 1.74 vs. 1.65 mPa/s; Chol: 309.8 +/- 41 vs. 217.1 +/- 30 mg/dl; all P less than 0.01); fibrinogen however, remained unchanged throughout the treatment period (346.4 +/- 73.3 vs. 330.5 +/- 70.2 mg/dl, n.s.). No differences were seen in hematocrit and platelet aggregability between hyperlipemic patients and controls and no changes occurred in these parameters during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Antiplatelet treatment prolongs survival after carotid bifurcation endarterectomy. Analysis of the clinical series followed by a controlled trial.

To examine the role of antiplatelet drugs in the secondary prevention of arteriosclerotic arterial disease following carotid endarterectomy, a clinical series (n = 252) was analyzed. Based on these results a prospective randomized trial was initiated, comparing the effect of antiplatelet drugs (acetyl-salicylic acid [ASA] 1000 mg/day) versus untreated controls. In both investigations patient survival was the primary end point. A cardiac risk (n = 91) implied a significant reduction in patient survival (p less than 0.019 Breslow, p less than 0.052 Mantel). Antiaggregating drugs prolonged survival in the collective series (p less than 0.0001 Breslow, p less than 0.0002 Mantel) and in the subgroup of patients with cardiac risk (p less than 0.014 Breslow, p less than 0.020 Mantel) as well. In the prospective trial 66 patients were recruited, receiving ASA (n = 32) versus no therapy (n = 34). During follow-up 15 patients died, 4 in the treatment, and 11 in the control group. Between both groups there was a significant difference in the probability of survival (p less than 0.021 Breslow, p less than 0.048 Mantel).

Aspirin↗

Platelets in hyperthyroidism: studies on platelet counts, mean platelet volume, 111-indium-labeled platelet kinetics, and platelet-associated immunoglobulins G and M.

We compared in 15 patients with hyperthyroidism (11 with Graves' disease, 3 with toxic adenoma, and 1 with multinodular goiter) platelet counts (PC) and mean platelet volume (MPV) before and 3 weeks after initiation of antithyroid drug therapy when the patients were euthyroid. In addition, platelet kinetic studies of autologous 111-indium-labeled platelets and platelet-associated immunoglobulins G and M (PAIgG and PAIgM, respectively) were investigated. The control group for the platelet kinetic studies consisted of 2 patients with diffuse nontoxic goiter and 86 patients who were studied for evaluation of their arteriosclerotic vascular disease. After 3 weeks of antithyroid drug therapy there was a significant increase in PC and a decrease in MPV compared with the pretreatment values (pretreatment PC median, 215 X 10(9)/L; range, 96-350 X 10(9)/L; PC median 3 weeks later, 248 X 10(9)/L; range, 157-384 X 10(9)/L; P less than 0.005; pretreatment MPV median, 10.6 fL; range, 9.1-13.2 fL; MPV 3 weeks later, 9.9 fL; range, 8.4-11.0 fL; P less than 0.005). 111-Indium platelet recovery was normal in all subjects. Platelet lifespan was significantly shortened in the patients with hyperthyroidism compared with the control group (median, 163.8 h; range, 128.5-206 h; vs. 180.0 h; range, 138.3-231.5 h; P less than 0.05). Platelet turnover averaged 45.6 (range, 25.6-71.9) X 10(9)/L.day; values above the limit of normal were found in 7 of 15 patients with hyperthyroidism. Three patients with Graves' disease had elevated levels of PAIgG; 1 of these patients had elevated levels of PAIgM and was the only patient with thrombocytopenia (PC, 96 X 10(9)/L). Various combinations of statistical correlations between the degree of hyperthyroidism, pretreatment PC and MPV, platelet kinetic studies, levels of PAIg, and serum levels of antithyroid antibodies revealed no significant differences. These findings suggest that the platelet changes observed in hyperthyroidism, such as lower PC and increased MPV, together with the shortened platelet lifespan reflect metabolically rather than immunologically mediated phenomena, although these may be involved in cases with marked thrombocytopenia.

Adolescent↗

Hemorheology in systemic ultrahigh-dose thrombolytic therapy with streptokinase and urokinase.

The course of fibrinogen (Fgen), red cell aggregation (RCA), plasma viscocity (PV), platelet aggregation (PA) and hematocrit (Hc) was studied in patients with ultrahigh - dose thrombolytic therapy (1.5 x 10(6) units/hour for 6 hours = 1 cycle) with streptokinase (SK) or urokinase (UK) over a period of 3 cycles. Both ultrahigh - dose SK and UK produced significant changes in the course of Fgen, RCA and PV, whereas PA (spontaneous and ADP-induced) and Hc remained unchanged. After termination of each cycle Fgen progressively increased while RCA and PV further decreased. The extent of alteration in cycle 1 - concerning the baseline values - was more pronounced with SK than with UK, but the overall effect of SK decreased through the consecutive cycles because of more rapid increase during the SK-free period. In UK-therapy hemorheological alterations were initially moderate but increased from cycle to cycle.

Adult↗

Thromboxane A2 and prostacyclin generation in the microvasculature of patients with atherosclerosis--effect of low-dose aspirin.

Generation of thromboxane A2 (TxA2) and prostacyclin (PGI2) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the microvasculature made to determine skin bleeding time was investigated in 7 patients with atherosclerosis (angiographically verified obstructions of the femoral arteries) and in 7 normal control subjects apparently free of atherosclerotic lesions. Similar amounts of TxA2 (measured as thromboxane B2, TxB2) were generated at the site of plug formation in the patients with peripheral vascular disease (PVD) and in the control subjects. Significantly lower levels of PGI2 (measured as 6-keto-prostaglandin F1 alpha, 6-keto-PGF1 alpha) were found in blood from an injury of the microvasculature in the patients compared with the controls. These data do not suggest a major role of the platelet prostaglandin metabolism in the development of atherosclerosis. However, decreased synthesis of PGI2 by endothelial cells might contribute to the development and/or progression of atherosclerotic lesions. In the patients with PVD, low-dose aspirin (50 mg/day for 7 days) resulted in a greater than 90% inhibition of the TxB2 production at the site of plug formation. Following low-dose aspirin 6-keto-PGF1 alpha levels were below 20 pg/ml (limit of sensitivity of our radioimmunoassay procedure) in the majority of the samples. We therefore conclude that in patients with PVD a decreased synthesis of PGI2 by endothelial cells might contribute to the progression of atherosclerosis. Furthermore, low-dose aspirin treatment results in a similar inhibition of the platelet prostaglandin generation as recently observed in healthy subjects.

6-Ketoprostaglandin F1 alpha↗

Accidental overdose of mitoxantrone in three patients.

Mitoxantrone is a new effective antineoplastic agent with activity against a wide range of tumors. Compared with the anthracycline drugs doxo- and daunorubicin, it exhibits a clearly lower toxicity and, most importantly, a reduced cardiotoxicity. The analysis of the side-effects recorded after accidental overdosage of the drug gives additional insight into its tolerability. Here we describe our observations in three patients who inadvertently received 100 mg m-2 (two pts) and 183 mg m-2 (one pt) as single slow bolus injections. The main side-effects were moderate nausea and vomiting, shaking chills, and profound but reversible neutro- and thrombocytopenia. There was no immediate cardiac toxicity. One patient with extensive previous daunomycin exposure developed congestive heart failure after 4 months. Two patients were not evaluable for late cardiac complications because of early death due to tumor progression.

Adult↗

Platelet deposition at angioplasty sites and its relation to restenosis in human iliac and femoropopliteal arteries.

The amount and time course of platelet accumulation at angioplasty sites and influence of these platelets on restenosis after percutaneous transluminal angioplasty (PTA) in peripheral arteries were determined in 92 patients, who received either a high or low dose of aspirin. Platelet deposition was quantitated by means of dual-radiotracer scintigraphy and calculation of a platelet accumulation index (PAI). The PAI was higher (P less than .05) 4-6 hours after PTA compared with that on subsequent days. There was a trend toward greater platelet accumulation in vessels with extensive dissection. Platelet accumulation at the PTA site occurred with both doses of aspirin, with no differences between the two dosage groups. Twenty-one of 67 patients who underwent PTA in the femoropopliteal segment developed restenosis during a median follow-up of 14 months. The median PAI at 4-6 and 22-24 hours after PTA was significantly less in these 21 patients than in the 46 without restenosis. The data suggest that use of antiplatelet agents to prevent platelet deposition after PTA may not be useful for prevention of restenosis.

Angioplasty, Balloon↗

Deep vein thrombosis: scintigraphic diagnosis with In-111-labeled monoclonal antifibrin antibodies.

Fifty-two patients suspected of having deep vein thrombosis under-went scintigraphy with an indium-111-labeled monoclonal antifibrin antibody. Venography disclosed deep vein thrombosis in 31 patients. With the whole limb considered an anatomic entity, antifibrin antibody scintigrams obtained 2 hours after injection had a specificity and sensitivity of 81% and 84%, respectively. A higher sensitivity (92%) was found for a subgroup of patients (n = 44) with symptoms for less than 10 days. Regional sensitivities for all patients and for the subgroup, respectively, were 92% and 100% in the calf, 82% and 94% in the popliteal region, 63% and 71% in the thigh, and only 18% and 13% in the pelvis. Additional imaging performed 6 hours and 21 hours after injection in 12 patients and quantitative analysis done from scintigrams with and without blood-pool (technetium-99m human serum albumin) correction did not improve sensitivity. In-111-antifibrin antibody scintigraphy is an accurate method for diagnosis of acute established deep vein thrombosis of the calf and popliteal region; its sensitivity in the thigh is lower, and it is not feasible for diagnosis in the pelvic area.

Adolescent↗

Indium-111-labeled platelet scintigraphy in carotid atherosclerosis.

We evaluated platelet accumulation in carotid arteries by means of a dual-radiotracer method, using indium-111-labeled platelets and technetium-99m-labeled human serum albumin, in 123 patients (92 men, 31 women; median age 60 years). Sixty patients had symptoms of transient ischemic carotid artery disease, and 63 patients with peripheral arterial occlusive disease served as controls. Antiplatelet treatment with acetylsalicylic acid was taken by 53 of the 123 patients. In 36 of the 60 symptomatic patients, platelet scintigraphy was repeated 3-4 days after carotid endarterectomy. Comparison of different scintigraphic parameters (platelet accumulation index and percent of the injected dose of labeled platelets at the carotid bifurcation) showed no significant differences between symptomatic and asymptomatic patients, and the severity of stenosis and the presence of plaque ulceration also had no influence on the parameters. There was no difference between patients with a short (less than 4 weeks) or long (greater than 4 weeks) interval from the last transient ischemic attack to scintigraphy and no difference between patients with or without antiplatelet treatment. Classifying the patients according to plaque morphology judged by high-resolution real-time ultrasonography also demonstrated no differences. No significant correlation was found between any scintigraphic parameter and other platelet function parameters such as platelet survival time, platelet turnover rate, and concentration of platelet-specific proteins. Quantification of platelet deposition after carotid endarterectomy in 36 patients demonstrated a significant increase of the median platelet accumulation index and the percent injected dose index. There were no significant differences between patients receiving high-dose (1.0 g/day) or low-dose (1.0 g/day) acetylsalicylic acid in scintigraphic results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Lack of influence of low-dose acetylsalicylic acid (100 mg daily) on platelet survival time, beta-thromboglobulin and platelet factor 4 in patients with peripheral arterial occlusive disease.

In this study we investigated the influence of low-dose (100 mg daily) acetylsalicylic acid (ASA) on 111-In-platelet survival time (PST) and on plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF 4) in 30 patients (median age: 60 years) with arteriographically proven peripheral arterial occlusive disease in a chronic stable phase. We observed no significant changes of PST during therapy with ASA (weighted mean: 169.8----166 [median] hours; multiple hit: 168.3----170.6 hours), and also the plasma levels of beta-TG (median: 31.8----32.3 ng/ml) and of PF 4 (3.6----3.9 ng/ml) remained unchanged.

Adult↗

Functional asplenia after bone marrow transplantation. A late complication related to extensive chronic graft-versus-host disease.

STUDY OBJECTIVE: To evaluate splenic function in bone marrow transplant recipients, with relation to chronic graft-versus-host disease and infections. DESIGN: Survey, outpatients geographically accessible for voluntary participation. SETTING: Bone marrow transplantation referral center. PATIENTS: Fifteen bone marrow graft recipients (13 allogeneic, 2 autologous), out of a total of 33 patients who received transplants at the center and survived more than 6 months after grafting. MEASUREMENTS AND MAIN RESULTS: In 6 of 15 patients impaired splenic function (functional asplenia) was indicated by the presence of Howell-Jolly bodies in peripheral blood smears, reduced spleen size (P less than 0.001), higher platelet counts (P less than 0.01), higher indium-111 labeled autologous platelet recovery (P less than 0.005), reduced splenic blood flow (P less than 0.001), and reduced accumulation of radioactivity at the splenic site (P less than 0.001). All patients with functional asplenia but only 2 patients without functional asplenia had extensive chronic graft-versus-host disease. The incidence of bacterial infections was four times higher in patients with impaired splenic function. CONCLUSIONS: Functional asplenia is a late complication after allogeneic bone marrow transplantation and contributes to the high susceptibility to bacterial infections in patients with extensive chronic graft-versus-host disease.

Adolescent↗

[Hemorheology and acute phase reaction following thrombendarterectomy of the extracranial carotid artery].

In 39 patients with hemodynamically significant stenoses of the internal carotid artery thrombendarterectomy was performed. Hemorheological properties and plasma protein levels were studied pre- and postoperatively over a period of 14 days. In comparison to age-matched healthy controls preoperative plasma viscosity, red cell aggregation, fibrinogen, haptoglobin and alpha-1-antitrypsin were significantly elevated. After surgical trauma there was an increase in fibrinogen, alpha-1-antitrypsin, haptoglobin and ceruloplasmin, whereas alpha-2-macroglobulin, immunoglobulin A and immunoglobulin G decreased significantly. Plasma viscosity, red cell aggregation, red cell filterability, fibronectin and immunoglobulin M remained unchanged. We conclude that our patients showed a non specific chronic "hematological stress syndrome" with raised acute phase reactants and corresponding hemorheological changes preoperatively; despite postoperative acute phase reaction no further deterioration of the rheological parameters could be observed; this might be caused by a decrease of plasma proteins with high frictional ratios compensating the increase of acute phase proteins. Besides, tissue damage and consecutive acute phase reaction in carotid arterial surgery seem to be of relatively minor degree.

Acute-Phase Proteins↗