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Biomedical subjects

R Dudczak

Publications and source records attributed to R Dudczak.

At least 109 records · Page 6Linked to original sources
PubMed1983

[Myocardial scintigraphy with iodine 123-labeled fatty acids].

This study presents experimental and clinical data in the use of I-123 labeled aromatic and aliphatic fatty acids. I-123 p-phenylpentadecanoic acid (p-IPPA) and I-123 heptadecanoic acid (HDA) were applied for myocardial scintigraphy. The feasibility of p-IPPA and HDA for myocardial scintigraphy was substantiated in animal experiments. Clinical studies were performed in patients with coronary artery disease (CAD) and cardiomyopathy (CMP). In CAD the results of fatty acid studies were compared with those of T1-201. Myocardial scintigraphy with p-IPPA and HDA was done with the patients supine and the collimator of the gamma camera in the LAO 45 grade position. Following intravenous administration of the labeled compounds data were continuously monitored. The regional distribution of the I-123 labeled fatty acids was assessed visually and supplemented with a semiquanitative analysis to estimate regional fatty acid uptake within the myocardium. The uptake was expressed as a ratio of background corrected regional myocardial activity to background activity (V. cava superior region). In initial studies data were accumulated for 40 minutes after intravenous HDA and for 50 minutes after intravenous p-IPPA, respectively. Data interpretation could be improved by an extended data acquisition (HDA: 70 minutes; p-IPPA: 90 minutes). In earlier experiments the decline in the myocardial count rate seemed to be monoexponential. However, in studies with prolonged data acquisition the myocardial time activity curve could be better described by two exponentials. Accordingly, the time activity curve was fitted with a biexponential function and the elimination half time of the initial and second component were determined. In addition, by extrapolation of the monoexponential slope of each component to zero, the size of each component was evaluated and the relative contribution of each phase on the myocardial elimination curve was expressed by a ratio of these extrapolated values. Our data provided evidence that I-123 labeled fatty acids can be used as metabolic tracers, as their kinetic behaviour was comparable to C-11 palmitate. Furthermore, in p-IPPA studies catabolites of its metabolic degradation were identified in plasma samples. Additionally it was shown in HDA studies that pharmacological interventions and acute ischemia were effective modulators of myocardial HDA utilization. In our patients we found a slower myocardial elimination half time for p-IPPA than for HDA; also the amount of p-IPPA utilized via the initial component was smaller than for HDA.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

[Protection from ionizing radiation in medicine].

Radiation burden of medical personnel is low in trained medical staff. Higher doses can occur with therapeutic application of unsealed or sealed sources, if adequate shielding is not possible or not cared for or if radiation protection measures are not observed in work with higher activities of radionuclides. More important than immoderate structural alterations for shielding purposes is individual inspection with advice on the working place and optimisation of working methods, also in regard to the radiation protection. This is possible only by cooperation and by discussing risks and problems between the radiation protection officer and the working personnel in an overt manner, assuring the mutual understanding. Radiation protection concerning medical uses of radiation in the whole population and in patients especially is determined by the necessity of indication for the medical application of radiation, by quality control and lastly by the correct interpretation of results or consequences. The latter necessitates a good collaboration between nuclear medicine specialists and clinicians because of the individual particularity of the patient which must be considered in the evaluation of results.

Adenoma↗
PubMed1983

[Diagnostic value of 201-thallium imaging following dipyridamole in patients with a normokinetic left ventricle].

In 100 patients with a normokinetic left ventricle 201-thallium imaging following administration of dipyridamole (0.50 mg/kg body wt. i.v.) showed a sensitivity of 67% (41/61) and a specificity of 95% (37/39) in diagnosing coronary artery disease. Exercise stress testing gave nearly equal sensitivity values (36/58 = 62%) with only slightly lower specificity (32/39 = 85%). The rate of true positive 201-thallium findings increased with the number of narrowed vessels (one vessel disease 50%, two vessel disease 63%, three vessel disease 94%); the extent of coronary artery disease was almost regularly underestimated with the scintigraphic method. Because of the low sensitivity a negative finding cannot exclude the presence of coronary artery disease, but the existence of three vessel disease can be considered improbable in patients in whom thallium scintigraphy findings are negative. Analysis following Bayes' theorem revealed the method to have a low diagnostic value in patients with either very low or high pretest probability for the disease; either a positive or a negative finding is of most use in a patient with low or average pretest probability of the disease (20-60%).

Coronary Disease↗
PubMed1982

Glycosylated hemoglobins (GHb): an index of red cell survival.

Levels of glycosylated hemoglobins (GHb) are significantly (p less than 0.0005) lower in patients with hemolytic anemia (n = 20; mean = 3.9% +/- 0.1% SD GHb of total Hb) compared to patients with nonhemolytic anemia (n = 20; mean = 7.0% +/- 0.7% GHb) and normal controls (n = 30; mean = 6.7% +/- 0.7% GHb). A curvilinear correlation between GHb and red cell survival is demonstrable (n = 20;r2 = 0.88; p less than 0.001). Determination of GHb may be useful as a screening test for hemolytic anemia and for the evaluation of the degree of hemolysis, provided that diabetes mellitus can be excluded.

Adolescent↗
PubMed1981

Plasma concentration of platelet-specific proteins and fibrinopeptide A in patients with artificial heart valves.

beta-Thromboglobulin (beta TG), platelet factor 4 (PF4), fibrinopeptide A (FPA), lactic dehydrogenase (LDH), and platelet count were evaluated in patients with bioprostheses and prosthetic heart valves. beta TG and PF4 were significantly elevated in both patient groups (p less than 0.001), whereas FPA was normal. There was no significantly difference in plasma concentrations of beta TG and PF4 between patients with prosthetic heart valves and bioprostheses. LDH levels were significantly (p less than 0.001) higher and platelet count lower (p less than 0.001) in patients with prosthetic cardiac valves. The data indicate that bioprostheses do not cause haemolysis or activation of the coagulation system. The findings that the plasma concentration of platelet-specific proteins were elevated, support the assumption that both types of valves cause platelet damage.

Adult↗
PubMed1981

[Thallium-201-myocardial imaging after high dose dipyridamole (author's transl)].

Biphasic thallium-201-myocardial imaging was performed in 100 patients undergoing coronary angiography. The images were obtained in several views after the administration of dipyridamole (0.50 mg/kg body weight) and 4 hours later. 24 patients had normal coronary arteries or insignificant stenoses, in 74 patients a 70-percent or greater stenosis of one or more coronary arteries was present. 55 transmural myocardial scars were diagnosed by left ventriculography in 53 patients. The described method showed a sensitivity of 93 percent and a specificity of 96 percent in the detection of patients with significant coronary artery stenoses. Irreversible perfusion defects were found in 91 percent of myocardial scars, in additional 7 percent the scintigraphic defects were reversible. In patients with multivessel disease and transmural infarctions, only one third of non-infarction-related stenoses were recognized. The number of angiographically stenotic coronary arteries could be determined scintigraphically only in a minority of the cases. The regional sensitivity in the assessment of LAD and right coronary artery stenoses was higher than for the left circumflex artery (75%, 80%, and 48% resp.), the specificity was equally high for all three vessels (96%, 99%, 100%).

Coronary Disease↗
PubMed1980

[The effect of the calciumantagonist dimeditiapramine on thallium-201 myocardial perfusion during exercise in patients with coronary heart disease (author's transl)].

The effect of dimeditiapramine (Ro 11-1781), a new calciumantagonist, on thallium-201 myocardial perfusion during exercise was studied in a double-blind trial with 10 patients suffering from coronary heart disease. Treatment with a single intravenous dose of 1 mg/kg body weight resulted in a significant regional thallium-201 perfusion increase in 8 out of 10 patients. These results correspond with the clinically observed decrease in exercise-induced angina and ischaemic ECG alterations. The findings indicate that dimeditiapramine might be a useful anti-anginal drug.

Aged↗
PubMed1980

Transient accumulation of Tc 99m MDP in the liver.

A patient with multiple myeloma complicated by hypercalcemia is presented. During the state of an elevated calcium phosphate product a transient diffuse accumulation of Tc 99m MDP in the liver was demonstrable, whereas the demonstrated metastatic calcifications of the kidneys persisted after therapeutic reduction of the elevated ion product. This points to a difference in the formation of calcium phosphate precipitations in these organs. Accumulation of Tc 99m labelled bone seeking agents in the liver must not always mean severe liver damage or amyloidosis or tumour manifestation. An altered serum calcium phosphate balance has to be taken into account when interpreting scintigrams performed with bone seeking radiopharmaceuticals.

Bone and Bones↗
PubMed1980

[Biphasic 201thallium scintigraphy after dipyridamole in mitral valve diseases (author's transl)].

The results of biphasic 201thallium scintigraphy after dipyridamole i.v. could neither prove nor exclude the presence of small focal lesions in the myocardium of 17 patients with mitral valve diseases. The frequent finding of a decrease in activity in the anterolateral myocardium is probably due to a relative increase in activity in the region of the inferior wall with superimposed areas of the papillary muscle and right ventricular myocardium. If the right ventricle is visualized in stress- or redistribution images, an increase in mean pulmonary artery pressure can be accepted. According to Cohen's criteria, a grade 2 or 3 virtually proves the existence of pulmonary hypertension, a grade 1 makes this finding rather probable. The possibility of pulmonary hypertension can not be excluded if the right ventricular myocardium is not visualized.

Adult↗
PubMed1980

[Amaurosis fungax. Studies on hemodynamics and platelet function].

Thirty-eight patients with amaurosis fugax were examined ophthalmologically. In 12 of these cases carotid occlusion was diagnosed by ophthalmodynamography and Doppler ultrasonography of the orbital vessels. Angiographic substantiation was possible in nine of these patients. The pathognomonic importance of amaurosis fugax for occlusive carotid disease is clearly shown by these findings. The plasma concentration of platelet specific proteins was examined in 32 patients and found to be pathologically increased in 13 cases. Spontaneous aggregation of platelets and circulating platelet aggregates were only found in a few patients. Due to the lack of coincidence between the event of amaurosis fugax and the time when platelet function tests were made no definite conclusions may be drawn from these results. Yet disturbances of platelet function must be taken into consideration in the pathogenesis of amaurosis fugax.

Adult↗
PubMed1980

Penbutolol: comparison of its antihypertensive effect with that of alpha-methyldopa in patients with primary hypertension.

The antihypertensive effect of 80 mg/day of the newly synthesized beta-blocker 1-tert. butylamino-3-(2-cyclo-pentylphenoxy)-2-propanol-sulfate (penbutolol, Hoe 893d) was studied in patients (n = 36) suffering from primary hypertension in comparison to the effect of 750 mg alpha-methyldopa/day. It was demonstrated that the therapeutic effect of both drugs is identical. Furthermore it was shown that the antihypertensive effect of penbutolol under an uncontrolled diet is unrelated to the patient's basal plasma-renin concentration.

Adolescent↗
PubMed1980

[Clinical significance of gamma camera renography in chronic renal insufficiency (author's transl)].

Gamma camera renography allows, together with renal imaging, an evaluation of individual renal function. For these examinations, J 123 orthoiodohippurate is preferred and most widely used. The results on patients with chronic renal insufficiency, including urologic and posttransplantation patients, are reported. Whereas the method is of clinical significance in evaluating posttransplantation complications and in assessing individual kidney function preoperatively in urology, as well as in monitoring therapeutic effects in the early period of renal disease, it is of limited diagnostic value in chronic renal insufficiency. In this latter regard, clinical and laboratory examinations are of primary importance.

Humans↗
PubMed1979

[Clinical significance of the radioimmunological determination of C-peptide (author's transl)].

The aim of this study was to investigate the relationship of metabolic control to insulinogenic reserve in insulin-dependent diabetics. Thus, the secretory reserve of the pancreatic beta cell was estimated in insulin-dependent diabetics by measuring changes in peripheral serum immunoreactive C-peptide (IRCP) concentrations in response to intravenous arginine (n = 19; 0.5 g/kg, t = 30 min) or glibenclamide-glucose (n = 6; 2 mg HB 419-0.33 g/kg intravenously). In the majority of "stable" diabetics a small secretory reserve of the beta cell was demonstrated, but both the absolute and relative increase in IRCP was reduced after intravenous arginine or glibenclamide-glucose in comparison with normal controls. In "unstable" diabetics a decreased basal concentration of IRCP, significantly smaller than that seen in "stable" diabetics (p less than 0.01), was accompanied by a complete lack of IRCP release on intravenous arginine administration. Thus, we conclude that the radioimmunological determination of IRCP is of clinical interest in assessing the residual secretory capacity of the beta cell in insulin-dependent diabetics. In revealing a lack of insulin this diagnostic tool seems to detect a group of potentially "unstable" diabetics in need of strict observation, which would minimize the risks of bad metabolic control.

Adult↗
PubMed1979

[Weight reduction in obese diabetics: a double-blind study of diethylpropionate (author's transl)].

In a double-blind study 40 overweight maturity-onset diabetics on a weight-reducing diet were randomly assigned to treatment with either the appetite-suppressant diethylpropion hydrochloride (Tenuate), or placebo. After treatment for 8 weeks the mean weight loss achieved by each group was 4.9 and 3.3%, respectively. This approximately equal weight loss was too slight to exert any significant effect on glucose tolerance. Thus, an additional effect of this anorexiant in comparison with diet restriction alone, as described in obese non-diabetic subjects, is not evident in the case of obese diabetic patients.

Clinical Trials as Topic↗
PubMed1979

[Radioimmunological determination of parathyroid hormone: regional localization in hypercalcaemic hyperparathyroidism (author's transl)].

Angiographic or scintigraphic localization of parathyroid adenomas is successful in only a small number of patients with hypercalcaemic hyperparathyroidism. This report is concerned with the preoperative localization of parathyroid adenomas by regional catheterization of the thyroid veins in patients with hypercalcaemic hyperparathyroidism (n = 7). PTH was determined radioimmunologically, using an antiserum specific for PTH1-84 and the carboxyl-terminal fragment of the hormone. Determination of regional differences in the plasma concentration of PTH permitted the preoperative localization of PTH secreting adenomas. The preoperative localization of parathyroid adenomas was confirmed in each instance by surgery. Thus, the regional determination of plasma PTH represents a tool to improve the preoperative localization of parathyroid adenomas in patients with hypercalcaemic hyperparathyroidism and, hence, to reduce the risk of an unsuccessful operation.

Adenoma↗
PubMed1979

Comparison of two different biliary agents in healthy subjects and in patients with liver disease.

The kinetics of the iminodiacetic acids, dimethyl and diethyl IDA were studied in patients without and with liver disease. Diethyl IDA seems to be superior to dimethyl IDA in its diagnostic usefulness. It shows lower urinary excretion and a faster liver uptake, leading to more pronounced differences in liver peak time and in liver elimination half time and to faster visualisation of the gall bladder in patients with liver disease. The enterohepatic reabsorption is negligible as shown by enteral administration of the radiopharmaceutical and monitoring blood activity. Therefore it is not necessary to correct time activity curves of the liver for the IDA secreted into the gastrointestinal system. The most valuable diagnostic information with this substances may be gained in investigations on cholecystectomized patients with cholestasis.

Humans↗