"Aspirin - resistance"? A few critical considerations on definition, terminology, diagnosis, clinical value, natural course of atherosclerotic disease, and therapeutic consequences.

Based upon various platelet function tests and the fact that patients experience vascular events despite taking acetylsalicylic acid (ASA or aspirin), it has been suggested that patients may become resistant to the action of this pharmacological compound. However, the term "aspirin resistance" was created almost two decades ago but is still not defined. Platelet function tests are not standardized, providing conflicting information and cut-off values are arbitrarily set. Interest comparison reveals low agreement. Even point of care tests have been introduced before appropriate validation. Inflammation may activate platelets, co-medication(s) may interfere significantly with aspirin action on platelets. Platelet function and Cox-inhibition are only some of the effects of aspirin on haemostatic regulation. One single test is not reliable to identify an altered response. Therefore, it may be more appropriate to speak about "treatment failure" to aspirin therapy than using the term "aspirin resistance". There is no evidence based justification from either the laboratory or the clinical point of view for platelet function testing in patients taking aspirin as well as from an economic standpoint. Until evidence based data from controlled studies will be available the term "aspirin resistance" should not be further used. A more robust monitoring of factors resulting in cardiovascular events such as inflammation is recommended.

[Complications during exercise testing]. / Komplikationen bei der Ergometrie.

Exercise electrocardiogram forms the basis for diagnosis of ischemia in coronary heart disease. Blood pressure behavior, physical fitness, training heart rate and possible cardiac arrhythmias can additionally be assessed using bicycle ergometry or treadmill testing. When the indications for and contraindications to exercise testing (either bicycle ergometry or treadmill testing) are closely observed, serious complications are rare. However, it is important that the treating physician is aware of and able to recognize possible complications. The present article discusses possible cardiovascular complications and their incidence.

Natriuretic peptides levels are related to HDL-cholesterol with no influence on endothelium dependent vasodilatation.

BACKGROUND: The natriuretic peptides, Brain Natriuretic Peptide (BNP), C-type Natriuretic Peptide (CNP), are mediators of cardiovascular homeostasis. The impairment of arterial ability to vasodilate, also known as endothelial dysfunction, represents the first stage of atherosclerotic damage and may be assessed as brachial flow mediated vasodilation (FMV) in human. Generally an altered brachial FMV is documented in association to several cardiovascular risk factors as hypercholesterolemia. Aim of the study was to evaluate the behaviour of BNP and CNP in hyperlipemia and the potential relationship to FMV. PATIENTS AND METHODS: Forty-four hyperlipemic patients (LDL-cholesterol > 130 mg/dl and/or triglycerides > 150, age 35-60 y) of both genders and 20 normolipemic patients, matched for age and sex were investigated. RESULTS: Patients had lower values of brachial FMV in comparison to controls (3.9 +/- 3.5 vs 7.5 +/- 0.5%, p < 0.005), no differences were observed in BNP (4.6 +/- 4.6 vs 5.9 +/- 3.4 ng/mL, p = n.s) and CNP (4.1 +/- 5.8 vs 5.7 +/- 3.3 ng/mL, p = n.s). Univariate analysis showed a positive correlation between BNP and HDL-cholesterol values (r = 0.36, p = 0.001). In the multivariate analysis, LDL-cholesterol (beta = -0.57), HDL-cholesterol (beta = 0.26) and brachial artery diameter (beta = -0.33) were predictors of brachial FMV. The only predictive variable for CNP was HDL-cholesterol (beta = 0.37). CONCLUSIONS: The present study suggested that natriuretic peptides, BNP and CNP, are not altered in patients affected by hypercholesterolemia. Nevertheless, the levels of HDL-cholesterol are strictly related to the values of CNP. This observation, in humans, adds another mechanism to the vascular control exerted by HDL.

Low cholesterol and cancer.

PURPOSE: The relation between plasma cholesterol (CH) concentration and mortality is complex. The plasma CH concentration correlates positively with mortality from coronary heart disease, but some studies have shown a negative relation with death from cancer. If these two relations reflect causal mechanisms that are reversible by changing the plasma CH concentration, the benefits of lipid reduction for heart disease might be offset by an increased mortality from cancer. Different aspects between lipid metabolism and cancer, as well as new insights into this interesting field, are discussed. METHODS: The literature was searched using MedLine through 1966 and January 1996. RESULTS: There is no evidence from the data available at present that the association between low CH and a higher risk of cancer is causal. CONCLUSION: This issue should not affect the advice on health matters offered by doctors, especially to patients with other risk factors for cardiovascular disease. The possibility that hypercholesterolemia (HC) drugs can induce a reduction of tumor-cell growth makes them potentially useful as an adjuvant to chemotherapy and ultimately increases the probabilities in the prevention and treatment of cancer.

Passive smoking and cardiovascular risk.

A possible relationship between passive smoking and coronary heart disease has been widely debated during the past decade. Convincing evidence links environmental (passive) tobacco smoke exposure to heart disease morbidity as well as mortality. In the United States, 37,000 coronary heart disease deaths per year are attributed to environmental tobacco smoke exposure, accounting for 70% of all deaths caused by environmental tobacco smoke. The analysis of 10 epidemiologic studies indicated a consistent dose-response effect related to exposure, but more proof is still needed. Evidence indicates that nonsmokers are more sensitive to smoke, including cardiovascular effects, and that sidestream smoke contains higher concentrations of gas constituents, including carbon monoxide. Pathophysiological and biochemical data after short- and long-term environmental tobacco smoke exposure show changes in endothelial and platelet function as well as exercise capacity similar to those in active smoking. Therefore, passive smoking is a relevant risk factor for heart disease morbidity and mortality.

Accumulation of oxidized LDL in human semilunar valves correlates with coronary atherosclerosis.

OBJECTIVE: Recent data indicate that oxidized low-density lipoprotein (ox-LDL) has several proatherogenic effects, e.g. induction of macrophage chemoattractants, adhesion molecules, cytokines, type-1 plasminogen activator inhibitor and platelet-derived growth factor A-chain by smooth muscle cells. Therefore, ox-LDL has been utilized as a marker of oxidative modification of proteins in atherosclerosis. Because heart valves consist of smooth muscle cells, fibroblasts and endothelial cells, and because valvular disease and coronary atherosclerosis could result from similar biological processes, we investigated ox-LDL accumulation in isolated aortic and pulmonary valves and coronary arteries from patients with angiographically proven coronary heart disease (CHD, n = 19), patients with idiopathic congestive heart failure (IDCM = idiopathic dilated cardiomyopathy, n = 20), and transplant donors. METHODS: Masson-Goldner staining and immunohistochemistry utilizing anti ox-LDL and CD68 were performed on paraffin sections of freshly isolated semilunar valves. Data were analyzed by digital image planimetry and by visual scoring of staining intensity. RESULTS: Ox-LDL immunoreactivity was identified in the vascular aspect of the attachment line, in the deep valve stroma, and in the ventricular and vascular endothelium of the semilunar valves, colocalizing with macrophages. Valvular ox-LDL area was significantly increased in CHD-patients (P < 0.03) and IDCM-patients (P < 0.04) compared with controls. More ox-LDL was accumulating in the pulmonary valves than in the aortic valves (P = 0.04) as assessed by area and staining intensity. Valvular ox-LDL area in pulmonary valve and aortic valve was significantly correlated with ox-LDL accumulation in the intimal layer (P < 0.001) and medial layer (P < 0.001) of coronary arteries from the same patients. CONCLUSION: The data suggest that the biological process leading to ox-LDL accumulation in coronary atherosclerosis also involves heart valves. Therefore, accumulation of the oxidative stress marker ox-LDL in heart valves illustrates atherosclerosis as an additional mechanisms accelerating valvular degeneration in these patients.

The isoprostane, 8-epi-PGF2 alpha, is accumulated in coronary arteries isolated from patients with coronary heart disease.

OBJECTIVE: In the present study we wanted to know whether 8-epi-PGF2 alpha, which belongs to the class of isoprostanes formed by free radical-mediated peroxidation of arachidonic acid and arachidonyl-containing phospholipids, is enriched in isolated coronary arteries of patients suffering from coronary heart disease (CHD, n = 23) who received allograft heart transplants as compared to vessels derived from patients with dilative cardiomyopathy (CMP, n = 19) or from healthy heart donors (controls, n = 6). METHODS: Sections from the isolated coronary arteries were analysed by semiquantitative immunohistochemistry by determining the area and intensity of positive reaction for 8-epi-PGF2 alpha in the vascular intima and media. In addition, the 8-epi-PGF2 alpha content was determined using a specific immunoassay after extraction and purification. RESULTS: The immunohistochemical results indicated that 8-epi-PGF2 alpha is significantly enriched in arteries from patients suffering from CHD as compared to CMP (P < 0.0001). In controls, significantly less immunostaining was observed. Furthermore, a significant positive correlation between semiquantitative immunohistochemistry and radioimmunological determination was observed too. CONCLUSIONS: From our findings we conclude that 8-epi-PGF2 alpha is especially accumulated in coronary arteries from CHD patients and therefore is likely to be involved in atherogenesis.

Prostaglandins and lipid modification.

Postaglandins(PG) and low-density lipoproteins (LDL) both are playing a key role in atherogenesis. Their interaction at the local vascular level is of central relevance in plaque formation and progression. Details of these complex actions however, still need to be elucidated. Lipoproteins are influencing the PG-production of arterial wall cells and platelets, while PGs in turn have been shown to regulate lipoprotein receptor binding and entry into the arterial wall. Modification of LDL severely influences arterial wall trapping and foam cell formation. During LDL-modification, isoprostanes, a new family of compounds generated by free radical catalysed action, independent of cyclooxygenase, are formed. 8-epi PGF(2alpha) the most well known member exerts a great variety of proatherogenic actions, among them vasoconstriction and platelet activation; it also serves as a mitogen and stimulator of endothelin release. The influence of various eicosanoids on lipoprotein modification, however, has not been assessed yet.

Platelet aggregation and reversible platelet aggregates in type I-diabetes staged by retinal fluorescein angiography.

In 70 patients with juvenile-onset, insulin-dependent (type I) diabetes and 75 age- and sex-matched controls the reversible platelet aggregates expressed as platelet count ratio (PCR) and the ADP-induced platelet aggregation were studied. Retinal microangiopathy was staged by retinal fluorescein angiography. The mean PCR of the patients (0.82 +/- 0.02) was statistically significantly lower than that of the controls (0.97 +/- 0.01). However, in different stages of retinopathy no significantly different PCR could be observed. ADP-induced platelet aggregation (0.5 and 1.0 micromol/l) exhibited a higher reactivity of diabetic platelets, but with the exception of tangent alpha (see later), the differences were not statistically significant in comparison to the controls. After collagen-induced platelet aggregation (0.5 and 1 microgram/ml) the lag time in diabetics was significantly (p less than 0.001) lower than in the controls, whereas the other quantitative parameters exhibited higher platelet reactivity in general, though not statistically significant. No relationship between PCR and the in vitro induced aggregation was found. The degree of retinopathy had no significant influence on platelet aggregation. In general, the data demonstrate an increase in sensitivity of platelets in juvenile-onset diabetics, whereas no influence of stage of microangiopathy could be detected.

Decreased susceptibility of low-density lipoproteins to in-vitro oxidation after dextran-sulfate LDL-apheresis treatment.

Low-density lipoproteins (LDL)-apheresis is a well established treatment of severe hypercholesterolemia resulting in fast clinical improvement and angiographically proven regression after 6 months of therapy. The underlying mechanisms, beside lipoprotein removal, are still under debate. Recently, oxidized LDL were shown to be of key importance in foam cell formation and atherosclerotic lesion development. We examined the influence of dextran-sulfate LDL-apheresis on the susceptibility of LDL to oxidation in 6 patients (5 males, 1 female, age: 41-60 years) suffering from severe heterozygous hypercholesterolemia or combined hyperlipidemia. LDL-apheresis influenced the oxidizability of LDL by a significant (P < 0.01) prolongation of the median of lag time (min) for LDL samples (before treatment 75, range: 31-176 versus after treatment 129.5, range 45-286). A significant (P < 0.01) difference could be also observed in the amount of conjugated dienes as expressed by the maximum rate in absorbance (before treatment 15.39, range: 5.29-21.22 versus after treatment 20.20, range 12.88-72.33). Thiobarbituric acid reactive substances (TBARS) formation was significantly decreased in LDL obtained after apheresis treatment as compared to pretreatment LDL. Electrophoretic mobility (EM) of LDL obtained before and after LDL-apheresis revealed a significant increase (P < 0.05) from a mean of 8.8 +/- 0.5 to a mean of 10.5 +/- 0.5 mm. The titers of plasma autoantibodies against oxLDL (oLAb) which varied considerably interindividually, were not influenced by LDL-apheresis treatment. Levels of F2-isoprostanes, as measured by plasma levels of 8-iso-prostaglandin-F2 alpha (8-iso-PGF2 alpha), reflecting oxidative stress, did not change, either. In summary, our findings provide evidence that even one single dextran sulfate LDL-apheresis treatment decreases LDL-oxidizability, which is an additional beneficial effect to that of lipid lowering.

Etofibrate increases binding of low and high density lipoprotein to human platelets of patients with type II hyperlipoproteinemia.

Previous work suggested an influence of etofibrate, a diester of nicotinic acid and clofibric acid, on lipoprotein receptors. Besides its beneficial effects on plasma lipoprotein levels of decrease in total cholesterol, LDL-cholesterol and triglycerides and increase in HDL-cholesterol, etofibrate was shown to inhibit platelet function. In order to further evaluate platelet-lipoprotein interactions, the effects of etofibrate on plasma lipids and lipoproteins on the specific binding of normal [111In]LDL and [111In]HDL onto platelets as well as its effect on platelet function were evaluated in 8 patients affected by Type II hyperlipoproteinemia (HLP). In all patients binding was saturable and indicated high affinity binding sites capable of binding 927 +/- 233 ng protein of [111In]LDL/10(9) platelets (Kd 12 +/- 3 micrograms protein/ml) and 1496 +/- 435 ng protein of [111In]HDL/10(9) platelets (Kd 14 +/- 3 micrograms protein/ml). The capacity of native LDL (HDL) to displace bound [111In]LDL ([111In]HDL) by half (IC50) amounted to 22 +/- 9 micrograms protein/ml (26 +/- 8 micrograms protein/ml). Following a 6-week treatment period with etofibrate (500 mg twice daily), decrease in plasma total cholesterol, LDL-cholesterol and apolipoprotein (apo) B and increase in HDL-cholesterol and apo AI was correlated to a significant (P < 0.01) increase in LDL- as well as HDL-receptor binding. The platelet binding capacity increased to 1085 +/- 212 ng protein/10(9) platelets (Kd 8 +/- 3 micrograms protein/ml) for [111In]LDL and to 1867 +/- 266 ng protein/10(9) platelets for [111In]HDL (Kd 11 +/- 3 micrograms protein/ml). Platelet function studies demonstrated significantly (P < 0.01) reduced platelet aggregation in response to ADP and thromboxane formation after 6 weeks of etofibrate therapy. These findings in patients with HPL Type II indicate in vivo upregulation of specific [111In]LDL as well as [111In]HDL binding sites on human platelets associated with reduced platelet activation following etofibrate therapy.

Dynamic changes of plasma lipids and lipoproteins in patients after transient ischemic attack or minor stroke.

PURPOSE: Only few data are available concerning variations of lipids and lipoproteins in the acute stage after ischemic cerebrovascular events. It was the aim of this study to investigate whether the lipid and lipoprotein levels obtained in the first few days after a transient ischemic attack (TIA) or a minor stroke (MS) actually reflect "correct' values or "changed' (ie, false low) values, as in patients after acute myocardial infarction. PATIENTS AND METHODS: Total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), and triglyceride (TG) levels of 37 unselected patients with TIA or MS were determined within 12-48 hours (Group A) or within 49-168 hours (Group B) after the acute event. After a mean observation period of 15.3 months, all patients were re-examined; the results were compared with those of the baseline evaluation. RESULTS: At the time of the baseline evaluation, TC and LDL-C levels of Group B patients were significantly lower than Group A levels. At the end of the observation period, however, Group A and Group B patients did not differ with regard to all four parameters. In comparison with the baseline examination, the values of Group A patients had not changed. In Group B patients, however, TC, HDL-C, LDL-C, and TG levels had significantly increased. CONCLUSION: Our results strongly suggest that lipid and lipoprotein levels of patients with TIA or MS should be assessed within a maximum of 48 hours after the acute event. If the examination cannot be performed within that period, the determination of reliable values is possible only after several weeks or months.

In vivo tracing of indium-111 oxine-labeled human peripheral blood mononuclear cells in patients with lymphatic malignancies.

The in vivo migration of [111In]oxine-labeled peripheral mononuclear cells (PMNC) was studied in 20 patients with various lymphatic malignancies and palpable enlarged lymph nodes. The maximal labeling dose of 10 microCi (0.37 MBq) [111In]oxine/10(8) PMNC was found not to adversely influence either cell viability or lymphocyte proliferation in vitro. For in vivo studies, 1.5 X 10(9) PMNC were gained by lymphapheresis and reinjected intravenously after radioactive labeling, 150 microCi (5.55 MBq). The labeling of enlarged palpable lymph nodes was achieved in three out of three patients with Hodgkin's disease and in five out of five with high-malignant lymphoma, whereas three out of seven patients with low malignant lymphoma and no patient with chronic lymphatic leukemia had positive lymph node imaging. We thus conclude that PMNC retain their ability to migrate after [111In]oxine labeling and that these cells traffic to involved lymph nodes of some, but not all hematologic malignancies.

Use of 99mTc-furifosmin scintigraphy--planar and SPECT--to evaluate suggestive palpable and nonpalpable breast lesions.

UNLABELLED: Our objective was to evaluate the role of 99mTc-furifosmin scintigraphy--planar and SPECT--in discriminating benign from malignant breast disease. METHODS: The trial was prospective, open, and diagnostic. We recruited 30 consecutive patients with 14 palpable and 16 nonpalpable breast lesions. After receiving informed consent, we injected 555-640 MBq 99mTc-furifosmin intravenously in the arm contralateral to the breast lesion. Planar imaging and SPECT were performed. All patients underwent excision of the tumor within 2 wk. Using histology as the gold standard, we calculated sensitivity, specificity, and positive and negative predictive values for 99mTc-furifosmin in planar and SPECT technique. RESULTS: For 18 malignant and 12 benign breast lesions, a sensitivity of 50% for planar imaging and 72% for SPECT was seen. Specificity and positive and negative predictive values were 83%, 82%, and 53%, respectively, for planar imaging and 50%, 68%, and 55%, respectively, for SPECT. For the 14 palpable tumors (10 malignant, 4 benign), which averaged 17+/-10 mm in size (size range, 4-45 mm), a sensitivity of 60% for planar imaging and 80% for SPECT was achieved. Sixteen lesions were not palpable (median size, 9+/-3 mm [size range, 4-13 mm]). In this subgroup, 99mTc-furifosmin scintigraphy yielded a sensitivity of 37% for planar and 62% for SPECT technique (P>0.05). CONCLUSION: 99mTc-furifosmin scintigraphy is not a potent competitor to established scintigraphic procedures. In comparing this tracer with 99mTc-sestamibi and 99mTc-tetrofosmin, we cannot recommend 99mTc-furifosmin for the diagnosis of breast cancer.

Uptake of 99mTc-MIBI and 99mTc-tetrofosmin into malignant versus nonmalignant breast cell lines.

UNLABELLED: The kinetics and cellular uptake of 99mTc-2-hexakis 2-methoxyiso-butyl-isonitrile (MIBI) and 99mTc-1 ,2-bis[bis(2-ethoxyethyl)phosphino]ethane (tetrofosmin) into malignant versus nonmalignant human breast cell lines were investigated and compared. METHODS: At specific intervals after incubation at 37 degrees C and 22 degrees C with 99mTc-MIBI or 99mTc-tetrofosmin, the uptake characteristics of radiotracers into human adenocarcinoma breast cell lines MCF-7 and SK-BR-3 and human breast, nontumor cell line HBL-100 were assessed. RESULTS: The uptake of 99mTc-MIBI and 99mTc-tetrofosmin was lower at an incubation temperature of 22 degrees C than that at 37 degrees C in the 3 cell lines. In MCF-7 and in SK-BR-3 cells the uptake of 99mTc-MIBI was significantly higher than the uptake of 99mTc-tetrofosmin. The uptake of 99mTc-MIBI was significantly higher into MCF-7 and SK-BR-3 cells than that into HBL-100 cells. In comparison with HBL-100 cells, uptake of 99mTc-tetrofosmin into SK-BR-3 cells was significantly higher, whereas uptake into MCF-7 cells was similar. CONCLUSION: In vitro data suggest that 99mTc-MIBI may be a better tracer than 99mTc-tetrofosmin for discrimination between malignant and nonmalignant breast disease.

Indium-111-labeled low-density lipoprotein binds with higher affinity to the human liver as compared to iodine-123-low-density-labeled lipoprotein.

The interaction of 111In-low-density lipoprotein (LDL) and 123I-LDL with human liver-plasma membranes was investigated and compared. LDLs were isolated by sequential ultracentrifugation and radiolabeled either with 123I (using lodogen or iodine-monochloride) each followed by purification with gel-chromatography or dialysis) or 111In (using cyclic DTPA-anhydride). LDL concentrations of 0.1 to 32 micrograms protein/ml were used for direct binding assays investigating the specific binding of labeled LDL (in the presence of a 50-fold excess of unlabeled LDL) to human liver apoB-receptors. In separate experiments, displacement of bound 111In-(123I)-LDL by unlabeled LDL was studied. Human liver plasma membranes bound 239 +/- 26 ng protein of 111In-LDL/mg protein and 148 +/- 18 ng protein of 123I-LDL/mg protein specifically (p less than 0.001). The corresponding dissociation constants were 0.6 +/- 0.2 and 1.2 +/- 0.7 micrograms protein/ml, respectively (p less than 0.001). The capacity of unlabeled LDL to displace bound 111In-LDL was four times higher than that for 123I-LDL (IC50: 1.7 +/- 0.7 versus 7.7 +/- 1.0 micrograms protein/ml). No significant differences among the different methods of iodination of LDL were found. The findings show that 111In-labeled lipoproteins might be a better ligand for lipoprotein-receptor binding studies as compared to radioiodinated lipoprotein products.

Influence of radiation synovectomy on articular cartilage, synovial thickness and enhancement as evidenced by MRI in patients with chronic synovitis.

UNLABELLED: Radiation synovectomy is a safe and effective treatment for chronic synovitis that is refractory to the repetitive, intra-articular application of glucocorticosteroids in patients with rheumatoid or seronegative arthritis. Short-term and long-term effects of radiation synovectomy on articular cartilage, synovial enhancement and thickness were assessed in a prospective, clinical trial by MRI. METHODS: Thirteen patients (mean age 39+/-13 y) were treated with a median activity of 8.4 GBq 165Dy ferric hydroxide, a radionuclide with favorable physical properties and a well-documented clinical safety and efficacy profile. MRI was performed on a 1.5-T MR unit using a circular polarized knee coil. RESULTS: After a mean observation period of 13 mo, a marked reduction in synovial enhancement was observed in 10 patients. The mean reduction in baseline synovial thickness (mean 7.6+/-3.0 mm) was 24% (P = 0.03) at 1 wk and 42% (P = 0.01) about 1 y after treatment, respectively. Clinically, 9 of 13 patients (69%) exhibited persistent response to radiation synovectomy. The local clinical score, as defined by the reduction in pain, pannus, joint effusion and by the increase in the range of motion, improved significantly (P = 0.01), from a median of 7 (range 4-10) to a median of 2 (range 0-9). One year after treatment, changes in the local clinical score were related to the decrease in synovial enhancement in MRI (r = 0.7, P = 0.008, n = 12). There were no persistent adverse effects, nor was there evidence for any severe radiation-induced damage to the articular cartilage. On later follow-up images, the structure of the articular cartilage remained unaltered in all but 3 patients, who had new, superficial erosions most likely attributed to an active disease with persistence of inflammation. CONCLUSION: This study suggests that radiation synovectomy with 165Dy-ferric hydroxide is effective in terms of reducing chronic synovitis without causing detectable harm to the articular cartilage, as shown by MRI.

Radiation synovectomy using 165Dy ferric-hydroxide and oxidative DNA damage in patients with different types of arthritis.

UNLABELLED: Radiation synovectomy is an effective treatment for chronic synovitis refractory to pharmacological treatment in patients with rheumatoid or seronegative arthritis. Concerns persist about possible radiation-induced cytogenetic damage after radiation synovectomy leading to recommendations to use this technique only in the elderly. Micronucleus (MN) frequency in lymphocytes and urinary excretion of 8-hydroxy-2'-deoxyguanosine (8OHdG) as an indicator of cellular oxidative DNA base damage are biomarkers of radiation-induced cytogenetic damage. The course of both biomarkers was studied in patients with different types of chronic synovitis undergoing radiation synovectomy with very short-lived 165Dy-ferric-hydroxide (DFH). METHODS: Radiation synovectomy of the knee was performed in 13 men and 12 women (mean age, 44+/-15 y) using a mean activity of 9.48+/-1.65 GBq 165Dy-DFH in 27 consecutive treatments. MN frequency in lymphocytes and urinary excretion of 8OHdG, measured by high-performance liquid chromatography, were assessed before and 4 (MN only) and 20 h after radiation synovectomy. RESULTS: Urinary excretion of 8OHdG in patients (in micromol/mol creatinine; pretreatment mean, 3.1+/-3.4; median, 2.27) was not significantly different from that in healthy volunteers (mean, 2.0+/-1.2; median, 1.87) and not altered by radiation synovectomy (post-treatment mean, 2.5+/-1.5; median, 2.04, NS). An increase in 8OHdG levels after radiation synovectomy of more than 1 SD was found in only 1 patient, who experienced leakage to the lymph nodes but who already had elevated urinary 8OHdG levels before treatment. The frequency of MN/500 binucleated cells (BNCs) was slightly lower in patients (pretreatment mean, 4.3+/-2.6; median, 4.25) than in healthy volunteers (mean, 5.4+/-2.3; median, 5.3) and did not significantly change after therapy, either (4-h post-treatment mean, 3.9+/-2.1, median, 3.8; 20-h post-treatment mean, 4.1+/-2, median 3.8 MN/500 BNC). In 22 of 27 treatments, no leakage to nontarget organs could be monitored, whereas leakage to the local lymph nodes and the liver was detected after 5 treatments. CONCLUSION: Radiation synovectomy using 165Dy-DFH causes no significant radiation burden to most patients as indicated by the absence of adverse changes in levels of biomarkers of cytogenetic damage and a low incidence of leakage. These data suggest that the risk of malignancy may not be elevated.

The behaviour of various platelet function tests during long-term prostacyclin infusion in patients with peripheral vascular disease.

In 20 patients with peripheral vascular disease treated with prostacyclin (5 ng/kg/min) we observed a significant activation of platelet function as measured by platelet proteins, ADP-induced aggregation platelet sensitivity and platelet count. Only the platelet survival was significantly prolonged by the treatment.