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Biomedical subjects

R Dudczak

Publications and source records attributed to R Dudczak.

At least 73 records · Page 4Linked to original sources
PubMed1989

Anticardiolipin antibodies are elevated in HIV-1 infected haemophiliacs but do not predict for disease progression.

Levels of anticardiolipin antibodies (ACA) were measured in 55 patients with haemophilia A in serum samples obtained in 1983 and in 1987. Twenty-one patients were negative for anti HIV-1 antibodies in 1983 and remained negative in 1987; 34 patients had anti HIV-1 antibodies in 1983; 17 of these latter patients remained asymptomatic, whereas 17 patients developed ARC or AIDS during the 4 years follow-up. Thirteen anti HIV-1 negative patients had elevated ACA levels in 1983; subsequently, a significant decrease was observed in all these subjects (p less than 0.001). All anti HIV-1 positive patients had elevated ACA levels in 1983; normal values were found in 9 patients in 1987. Yet, these changes were not significant (p greater than 0.05). ACA levels were significantly higher in HIV-1 infected patients than in those without anti HIV-1 antibodies (p less than 0.05). There was no difference of ACA levels between the two anti HIV-1 positive patient groups, be it in 1983 or be it in 1987 (p greater than 0.05). There was no correlation of ACA levels with serum IgG concentrations, CD4+ lymphocytes, or the consumption of factor VIII concentrates.

Acquired Immunodeficiency Syndrome↗
PubMed1989

"False positive" immunoscintigraphic diagnosis of liver abscesses in a patient with a necrotic liver tumour.

The following report describes the scintigraphic findings in a patient who underwent immunoscintigraphy with anti granulocyte Mab because of septic fever. Focal tracer accumulation in the liver corresponding with hypoechoic and hypodense areas documented by sonography and computed tomography was believed to represent liver abscesses, yet surgery and autopsy revealed a large necrotic cholangiocellular liver carcinoma. The possible mechanisms, which had led to the false positive immunoscintigraphic image are discussed and we conclude that a necrotic neoplasm has to be a major differential diagnosis in any case of positive liver uptake in an anti granulocyte scan.

Adenoma, Bile Duct↗
PubMed1989

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↗
PubMed1989

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↗
PubMed1989

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↗
PubMed1988

Further evidence for lymphokine overproduction in severe aplastic anemia.

Interferon-gamma (IFN-gamma) and tumor necrosis factor (TNF) are lymphokines with a potent hematopoietic progenitor cell suppressive capacity. In untreated and immunosuppressed patients with severe aplastic anemia (SAA) and in control individuals we measured (a) serum levels of IFN-gamma and TNF and its production by peripheral blood mononuclear cells (PBMNC); (b) serum levels of neopterin, a product that reflects endogenous IFN production; (c) resting and activated lymphocyte subpopulations; and (d) serum levels of soluble interleukin-2 receptor (IL-2R). Serum levels of IFN and TNF did not differ significantly in untreated and treated SAA patients and control individuals. Spontaneous and phytohemagglutinin-induced production of IFN and TNF by PBMNC, however, were highly increased in both untreated and treated SAA patients. Increased and decreased neopterin serum levels in untreated and treated SAA patients, respectively, suggest modulation of endogenous lymphokine release subsequent to immunosuppression. HLA-DR+ antigen was mainly expressed by CD8 T cells. Circulating numbers of activated (CD4 and CD8) T cells and serum levels of IL-2R were not increased in both untreated and treated SAA patients. The proportion of HLA-DR+ T cells in the PBMNC of untreated SAA patients correlated with the extent of lectin-induced IFN production. Although we were unable to confirm previous reports in SAA on (a) detectable IFN in blood and bone marrow serum, (b) improvement of stem cell growth upon neutralization of endogenous IFN, (c) absolutely increased numbers of circulating activated T cells, and (d) normalization of these abnormalities subsequent to successful immunosuppression, our data clearly support previous reports on abnormal lymphokine production in severe aplastic anemia. Our failure to relate this phenomenon to the severity of disease states, however, further raises doubts on the pathogenetic significance of lymphokine overproduction in SAA.

Adolescent↗
PubMed1987

Platelet deposition at angioplasty sites and platelet survival time after PTA in iliac and femoral arteries: investigations with indium-111-oxine labelled platelets in patients with ASA (1.0 g/day)-therapy.

In this study we have assessed the deposition of 111-In-oxine-labelled platelets--using a dual radiotracer method--at angioplasty sites of the lower extremities in 20 patients (14 male, 6 female; median age: 60 years) with ASA (1.0 g/day)-therapy. The platelet survival time (PST)--using the multiple hit model--was evaluated before and after percutaneous transluminal angioplasty, and we also measured the plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF 4) before and after PTA. Before PTA, scintigraphy was positive in only one patient, while 24 hours after PTA a positive scintigraphic result was observed in 16/20 patients. The median target/non target-ratio was 1.0 (0.66-1.3) before PTA, and this ratio increased significantly (p less than 0.0005) to 1.53 (1.0-3.3) after PTA. The median PST decreased significantly (185.0 hours before PTA----145.2 hours after PTA; p less than 0.001), while the median platelet turnover increased from 34,000/microliter/day to 47,900/microliter/day (p less than 0.01). The median plasma levels of the platelet specific proteins increased significantly immediately after PTA (p less than 0.001), but one day later they were not significantly different from the pretreatment values. The quantitative methods used in this study seem a valuable tool to evaluate the effects of different therapeutical--especially antiplatelet--interventions after PTA in humans, thus helping to find the best antithrombotic regimen for this widely used therapeutical procedure.

Adult↗
PubMed1987

[Immunoscintigraphy with a technetium 99m-labeled monoclonal antibody in patients with melanoma].

In 24 patients with malignant melanoma the clinical feasibility of immunoscintigraphy (ISC) with a Tc99m-labeled F(ab)2 fragment of an anti-melanoma monoclonal antibody was evaluated. This antibody (225.28S) recognizes a human high molecular weight melanoma associated antigen with restricted tissue distribution, which is expressed on melanoma cells in about 90%. The results of ISC were related with the clinical stage of the patients and the level of invasion of the primary tumor (Clark level). Results of ISC indicate the possibility that patients with the highest Clark level have a higher incidence of false negative scintigrams than those with lower levels of invasion of the primary tumor. In 3 out of 5 patients with Clark level 5 false negative scintigrams were found, whereas in 14 patients with lower Clark levels ISC was true positive, however, the number of metastases was underestimated. 14 of 18 patients with clinical stage II-IIIb had positive scans visualizing 27 of 59 metastases. Thus overall sensitivity was 77% and regional sensitivity 46%. Scintigraphically lesions in lymph-nodes, liver and skin were frequently detected, whereas ISC was less sensitive for lung, bone and brain metastases. No false positive findings were observed by ISC (specificity 100%). Relating the sensitivity and specificity of ISC to the prevalance of disease post-test likelihoods for a normal and an abnormal test result were calculated. Post-test likelihood for the disease with an abnormal scintigraphic finding is 100%. However, with a disease prevalance of 75%, according to our patients, the predicitive value of a normal test result is 60%, thus the post-test likelihood for the disease remains rather high (40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Reproducibility of myocardial thallium-201 washout in studies applying a standardized dipyridamole stress protocol.

Thallium-201 (201Tl) washout analysis was proposed as an adjunctive tool to improve the detection of coronary artery disease (CAD). Since reproducibility of 201Tl washout in dipyridamole (DPM) stress studies is unknown, this item was evaluated in 32 patients (24 with CAD, 8 without CAD), who were scintigraphed twice within 1-2 weeks. At 2 minutes following DPM infusion (0.5 mg/kg/5 min), 2 mCi 201Tl were injected. Global and segmental washout were calculated by comparing circumferential profiles of respective background-corrected stress (left anterior oblique (LAO) 45 degrees: 8 min postinfusion (p.i.), 35 min p.i.; anterior (ANT): 17 min p.i.; LAO 70 degrees: 26 min p.i.) and redistribution (4 h p.i.) images. Whereas visual findings were comparable for study I and II, reproducibility of 201Tl washout was low, indicated by comparing variances among patients with variance between studies, which were 28.8 and 71.2% of total variance, respectively. Mean differences of segmental washout between the studies ranged from 9.75 to 19.24% with only minor differences with regard to the different views and segments evaluated. Variability was lower using the intermediate instead of the initial scintigram as reference for the redistribution image (12.87 +/- 11.64% vs. 18.59 +/- 14.43%, n = 85; p less than 0.01). Variability was higher for nonstenosed compared to stenosed segments (14.54 +/- 11.41%, n = 32 vs. 9.89 +/- 8.03%, n = 28, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1987

[Myocardial scintigraphy using cationic 99m Tc complexes].

This report summarizes the results which have been achieved by the use of 99mTc-labeled cationic complexes for myocardial scintigraphy. Radiopharmacological aspects of 99mTc(III)-Cl2 (DMPE)2 and 99mTc(I)-TBl as well as their scintigraphic behaviour in patients with coronary artery disease are described. In contrast to 99mTc-Cl2 (DMPE)2, 99mTc-TBl could be used successfully for the assessment of ischemic and infarcted myocardial tissue. Yet in general, 201Tl scintigraphic findings remained superior. However, from the considerable improvements achieved it is likely that soon a 99mTc-labeled tracer will be available to serve as clinical useful myocardial imaging agent.

Animals↗
PubMed1986

Structurally modified fatty acids: clinical potential as tracers of metabolism.

Recently 15-p-iodophenyl-beta-methyl-pentadecanoic acid (BMPPA) was proposed for use in myocardial scintigraphy, as a possible probe of metabolic processes other than beta-oxidation. In 19 patients (CAD/15, St.p. Mi/7; control 4) myocardial scintigraphy was carried out after i.v. I-123-BMPPA (2-4 mCi). Data were collected (LAO 45 degrees/14; anterior/5) for 100 min in the fasted patients. Organ to background (BG) ratios were calculated for the heart (H) and liver (L), and the elimination (E) behaviour was analyzed from BG (vena cava region) corrected time activity curves. In 10 patients plasma and urine were examined. By CHCl3/MeOH extraction of plasma samples (90 min after injection), both in water and in organic medium soluble catabolites were found. TLC fractionation showed that those were co-migrating, compared to standards, with bencoic acid, BMPPA and triglycerides. In the urine (0-2 h after injection, 4.1% dose) hippuric acid was found. The mean t-max of BMPPA occurred at 15 min in the heart and at 9 min in the liver (P less than 0.01), with H/BG and L/BG ratios of 1.8 and 2.1, respectively. The elimination of BMPPA was slower from the heart than from the liver (P less than 0.01). It was biexponential from the liver in all cases (means: t/2 I, 11.4 min; t/2 II, 92 min; t/2 I uncor., 38 min) with the size of phase I smaller than that of phase II (means: I/II, 0.57). From the heart BMPPA turnover was biexponential in 11 patients (means: t/2 I, 13.8 min; t/2 II, 187 min; t/2 I uncor., 65 min; I/II, 0.34), but monoexponential in 8 (means: t/2, 218 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1986

Platelet-associated immunoglobulins IgG, IgM, IgA and complement C3c in chronic idiopathic autoimmune thrombocytopenia: relation to the sequestration pattern of 111indium labelled platelets.

Levels of platelet-associated immunoglobulins (PAIg) IgG, IgM, IgA and complement C3c were related to parameters of 111Indium-labelled platelet kinetics in 17 patients with chronic idiopathic autoimmune thrombocytopenia (cAITP). Elevated levels of PAIg/C3c were found in 14 patients (82%) (PAIgG n = 13, PAIgM n = 11, PAIgA n = 1, PAC3c n = 5). Only PAIgG correlated with platelet counts (RS = -0.71, p less than 0.01). Mean platelet life span (MLS) was shortened in all patients (median 12.0 h, range 0.3-45.6 h) and correlated with the platelet counts (RS = 0.49, p less than 0.05). MLS was correlated with PAIgG (RS = -0.52, p less than 0.05), but not with PAIgM, PAIgA, or PAC3c. The site of sequestration was splenic in 10 patients and splenic-hepatic in 7 patients. Although no significant correlation between either site of platelet sequestration and any of the investigated PAIg/C3c was demonstrable, platelets coated with higher PAIgG levels were more readily sequestrated in the spleen, while elevations of PAC3c were found in 4 out of 7 patients with hepatic involvement.

Adolescent↗
PubMed1985

Clinical comparison of 99mTc-HMDP and 99mTc-MDP. A multicenter study.

99mTc-Hydroxymethylene diphosphonate (HMDP) was compared to 99mTc-methylene diphosphonate (MDP) with respect to image quality, lesion detectability, and the uptake ratios of normal bone to soft tissue (B/S), metastatic bone to soft tissue (M/S) and bone metastases to normal bone (M/B) at 2 and 3 h after injection in the same subjects. Thirty-three patients with bone metastases were examined in six nuclear-medicine departments, with each center using its usual bone-scanning protocol which was identical for both compounds in the same patient. The uptake of 99mTc-HMDP in normal bone (B/S) was significantly higher than that of MDP at 2 and 3 h, but there were no significant differences between the two compounds with regard to the M/S or M/B ratios. The M/B of HMDP at 2 h was not significantly different from that of MDP at 3 h, the latter showing a significantly higher B/S and M/S ratio. All lesions were detected with both compounds, even at 2 h. The image quality was rated as follows (in decreasing order): HMDP (3 h), MDP (3 h), HMDP (2 h), and MDP (2 h). HMDP was shown to be a useful bone-imaging agent, especially when shorter intervals between injection and recording are required.

Adult↗
PubMed1985

Deficiency of fibrinogen and factor VII following treatment of severe aplastic anaemia with anti-thymocyte globulin and high-dose methylprednisolone.

In 4 patients with SAA treated with ATG and high-dose MP, an as yet unrecognized acquired deficiency of fibrinogen and factor VII was observed. The plasma level of fibrinogen fell to 39% (34-51%) and of factor VII:C to 50% (31-55%) of the pretreatment value. The nadirs were between days 10 and 35 (fibrinogen) and d 3 and 11 (factor VII) after the 1st dose of ATG/MP. From additional clotting studies it is concluded that disseminated intravascular coagulation, fibrinolysis, liver cell damage and synthesis of abnormal clotting factors are unlikely causes of these clotting abnormalities. The most probable explanation seems to be a selective inhibition of the synthesis of fibrinogen and factor VII by an as yet unknown mechanism. These clotting abnormalities might, to some extent, increase the bleeding tendency in these patients, which up to now had been solely attributed to thrombocytopenia.

Adult↗