Biomedical subjects

R Dudczak

Publications and source records attributed to R Dudczak.

At least 91 records · Page 5Linked to original sources

PubMed1985

Myocardial studies in haemodialysis patients.

Myocardial perfusion was studied using Thallium-201 (Tl-201) after dipyridamol in 33 patients on maintenance haemodialysis. It could be shown that coronary artery disease was underestimated by clinical symptoms, 55 per cent of patients had abnormal Tl-201 scintigrams, whereas typical or atypical chest pain was present in only 33 per cent of the patients. Eleven patients died within a year of the scintigraphic study, which resulted in an average mortality rate of 7.7 per cent/year. The risk of developing fatal cardiovascular complications was higher in patients with an abnormal Tl-201 perfusion (7 of 18) than in those with a normal scintigram (1 of 15). Thus nuclear medicine procedures appear to be of diagnostic value in haemodialysis patients, which in addition may have prognostic implications.

Adult↗

PubMed1984

Effect of combination therapy with cimetidine and pirenzepine on plasma parathyroid hormone and calcitonin levels in hemodialyzed patients.

In this study we evaluated the effects of an oral combination therapy with cimetidine and pirenzepine on plasma parathyroidhormone (PTH) and calcitonin (CT) levels in 24 patients on maintenance hemodialysis (mean age: 50 years; mean duration of dialysis treatment: 23 months). As compared to the pre-treatment plasma levels of PTH and CT, there were no significant changes of their plasma concentrations during a 4-week administration of 800 mg cimetidine or 100 mg pirenzepine daily, and the concentrations also did not change significantly during the following 4 weeks of combination therapy with cimetidine and pirenzepine in the above mentioned dosage. Serum concentrations of calcium and phosphate and the activity of the alkaline phosphatase showed no significant changes either. Therefore, we suggest that this therapeutic approach cannot be considered for the treatment of uremic hyperparathyroidism.

Adolescent↗

PubMed1984

[Radionuclide studies in chronically hemodialyzed patients. Bone scintigraphy for the evaluation and control of renal osteopathy].

The clinical applicability of bone scintigraphy (Tc99m MDP) was evaluated in 42 patients on maintenance hemodialysis. Typical scintigraphic findings are shown which were related to hormonal and biochemical parameters of calcium and phosphate metabolism. Visual grading of representative regions for metabolic bone disease in bone scans was compared to scintimetry which applies a bone to soft tissue ratio to grade osseous abnormalities. It could be shown that visual interpretation and grading of the findings according to a score is sufficient to assess the degree and extent of renal bone disease. Semiquantitative analysis of bone scintigrams by scintimetry did not improve the diagnostic information.

Adult↗

PubMed1984

[Mitoxantrone in the primary treatment of metastasizing breast cancer].

25 females (57.7 +/- 11.1 years) and 1 male (71 years) with histologically verified metastasizing breast cancer were submitted to mitoxantrone therapy. Secondary tumours were found in following organ systems: bone: 19 cases; lung: 13 cases; liver: 6 cases; skin: 5 cases; locoregional and nodal: 5 cases; brain: 1 case. All patients showed normal bone marrow and heart function before commencement of treatment. Mitoxantrone was given in form of a 30-minute infusion at a dosage of 14 mg/m2. In 4 patients dosage was increased to 20 mg/m2. Treatment cycles were repeated every 3 weeks according to peripheral blood counts. All patients were cardiologically monitored throughout the study by means of electrocardiogram, systolic time interval measurement and radionuclide angiography. The mean observation period was 169 +/- 98 days. The response of the patients was as follows: 1 complete remission, 5 partial remissions, 4 unchanged disease and 16 progressive disease. Side effects were normally mild; only nausea, leucopenia and moderate hair loss were of clinical relevance. Cardiac decompensation was not observed. No significant electrocardiographic alterations were found throughout the study. Results of systolic time interval measurements (PEPI, PEP:LVET) and radionuclide angiography (LVEF) gave evidence of moderate depression of heart function. In view of the optimal benefit/risk ratio of mitoxantrone this drug could be used in combined modality treatment schedules in metastasizing breast cancer.

Aged↗

PubMed1984

[Radionuclide studies in chronically hemodialyzed patients. Diagnosis of coronary disease using Tl-201 myocardial scintigraphy after administration of dipyridamole].

Myocardial perfusion using Tl 201 after dipyridamol was evaluated in 33 patients on maintenance hemodialysis. In addition radionuclide angiography (RNA) was performed following hemodialysis to assess left ventricular function. RNA was done at rest in 31 patients and repeated in 13 after isometric exercise. All patients studied showed no signs of congestive heart failure. 55% of the patients had abnormal Tl 201 scintigrams, whereas coronary artery disease (CAD) was underestimated from clinical symptoms alone (33%). The incidence of an abnormal Tl 201 finding increased with the duration of hemodialysis treatment. However, in the symptomatic patients angina appeared already in the first (45%) or second year of hemodialysis treatment. 39% of patients with abnormal Tl 201 findings died within a year following scintigraphic examination. From 15 patients with normal Tl 201 scans 26% died. Overall mortality rate was above that in asymptomatic or mildly symptomatic patients with CAD, averaging about 7.7% per day. The major causes of death were cardiovascular complications in patients with abnormal Tl 201 findings. In all patients left ventricular ejection fraction (LVEF) was within the normal range following hemodialysis. Thus in our patients LVEF appeared not as an important prognostic characteristic. However, ventricular function can be impaired following exercise. As expected, in 7 patients with CAD (abnormal Tl 201 scan) isometric handgrip induced a mean decrease in LVEF by 11% and abnormalities in regional wall motion. However, also in 4 of 6 patients with normal Tl 201 scintigrams LVEF decreased following isometric exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1984

[Changes in the left ventricular ejection fraction during exercise and in the thallium-201 perfusion after administration of dipyridamole in patients with coronary disease].

46 patients with coronary artery disease (at least 70% stenoses) were studied with thallium-201 imaging following dipyridamole (0.50 mg/kg bodyweight intravenously) with 4-hour control and by radionuclide ventriculography at rest and during symptom-limited bicycle exercise in supine position. 38 patients (83%) had positive thallium-201 findings with persistent defects in 18 and transient defects in 20 cases. Mean left ventricular ejection fraction (EF) fell during exercise from 56.1% +/- 13.3 to 50.2% +/- 14.5 (p less than 0.001). 43 patients (93%) showed an abnormal EF response to exercise (rise of less than 10% of the control EF during exercise). In 8 patients with false negative thallium-findings the EF did not change from rest to exercise (64.1% +/- 10.0 vs. 64.6% +/- 8.5), however, in the 20 patients with transient Tl-201 defects a significant fall of the EF was noted (60.8% +/- 9.1 vs. 49.8% +/- 10.9, p less than 0.001), in the 18 patients with persistent defects only a slight decrease of the EF was induced with exercise (47.3% +/- 14.0 vs. 44.2% +/- 16.1, p less than 0.02). Thus transient Tl-201 defects usually predict functional impairment of the left ventricle with exercise, persistent defects suggest impaired rest function with only minor further dysfunction during exercise. Compared with rest and exercise ECG in these patients, both radionuclide techniques showed a significantly higher sensitivity.

Adult↗

PubMed1984

Impact of thallium-201 imaging on clinical assessment and management of patients with chest pain.

The histories, rest, and exercise ECG results of 60 patients without myocardial infarction complaining of chest pain were submitted to 6 physicians (3 cardiologists and 3 noncardiologists) who were unaware of the angiographic findings. The physicians were requested to estimate the probability of coronary artery disease present in percentages and to assess the need for coronary angiography on a five-point scale (1 = definitely not indicated, 5 = definitely indicated). After obtaining the results of thallium-201 imaging following dipyridamole (0.50 mg/kg intravenously) administration, the physicians were again requested to estimate probability and need for angiography. In the 43 patients with coronary artery disease the judgment of probability was increased significantly after 201Tl from 75.6 +/- 20.2% to 82.9 +/- 23.2% (p less than 0.001) and the need for angiography from 4.3 +/- 0.9% to 4.5 +/- 0.9% (p less than 0.001). In the subgroup of patients with atypical angina the relative change in probability was higher than in other subgroups of patients with coronary artery disease. In the 17 patients with normal coronary arteries the probability estimation fell after 201Tl from 36.7 +/- 22.0% to 24.8 +/- 21.0% (p less than 0.001), the need for angiography was decreased from 2.7 +/- 1.1% to 2.2 +/- 1.2% (p less than 0.001). With the 201Tl information, cardiologists performed a better diagnostic differentiation of patients with and without coronary artery disease than noncardiologists. The study demonstrates the improvement of clinical diagnosis in patients with chest pain by thallium-201 imaging and confirms the favorable influence of the method on the management of the patients in terms of indications for coronary angiography.

Angiography↗

PubMed1984

The use of 123I-labeled heptadecanoic acid (HDA) as metabolic tracer: preliminary report.

The feasibility of using 123I-heptadecanoic acid (HDA) as a metabolic tracer was studied. Different administration routes of HDA were compared. An intracoronary bolus injection was given to calves (n = 3), and an intravenous injection was given to patients (n = 4). In addition, we examined the influence of 4-h halothane anesthesia in calves and in patients the impact of an insulin (1.5 IU/kg) + glucose (1.5 g/kg) infusion on the myocardial kinetics of HDA. Data were accumulated with a scintillation probe in calves (t = 50 min) and a gamma camera in patients (t = 70 min). In calves after an intracoronary bolus injection of HDA the myocardial time-activity curve could be described by two exponentials. The mean elimination half-time of the initial phase (ta 1/2) was 7.3 min and that of the second phase (tb 1/2) was 35 min. The ratio of the size of the initial and second component at to was 0.93. Halothane anesthesia prolonged the elimination half-times and reduced the component ratio. The biphasic behavior of the myocardial time-activity curve was maintained in patients after intravenous administration of HDA under basal conditions (initial ta 1/2 = 8.4 min). However, during infusion of insulin + glucose the decline in the myocardial activity was prolonged and monoexponential. This data shows that insulin glucose, interfering with fatty acid metabolism, influences the myocardial washout of HDA, and thus support its use as a metabolic tracer.

Animals↗

PubMed1984

[Reproducibility of repeated measurements using M-mode echocardiography, radionuclide ventriculoradiography and systolic time intervals].

The reproducibility of M-mode echocardiography, radionuclide ventriculography, and systolic time intervals (PEP/LVET) was studied in 16 patients with symmetrically contracting left ventricles and no signs of coronary heart disease. The values were determined four times in these 16 patients: twice each on day 1 and day 8 at an interval of 2-3 h. The mean EF and PEP/LVET values were nearly identical in all 4 repeat studies. There was a high correlation of echocardiographic and scintigraphic EF measurements (r between 0.90 and 0.96); the correlation between PEP/LVET and EF was considerably poorer (r ranging from -0.56 to -0.79). There was no difference in mean serial variabilities of EF for all repeated studies performed on the same day and on separate days for either echocardiography or radionuclide ventriculography. The mean variability of absolute EF for repeated studies was 2.9 +/- 2.4% for M-mode echocardiography and 3.4 +/- 2.4% for radionuclide ventriculography. To be attributed to nonrandom physiological alterations the absolute change in EF in an individual patient should be at least 8% for echocardiography and 9% for radionuclide ventriculography. The mean variabilities of PEP/LVET were different in studies performed on the same day and on separate days (0.03 +/- 0.02 vs 0.04 +/- 0.03, p less than 0.01). In 7 further patients the effect of dobutamine infusion was studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1983

[Monitoring of cardiac function during doxorubicin therapy in metastasized breast cancer. Measuring systolic time interval].

Assessment of systolic time interval represents an uncomplicated, sufficiently precise and cheap possibility in clinical practice of cardiac monitoring during treatment with doxorubicin (adriamycin) if the ratio between pre-ejection period interval (PEPI) and left ventricular ejection time interval (LVETI) ("Weissler index") for evaluation of left ventricular cardiac function is used. In an investigation of 352 female patients with metastatic carcinoma of the breast statistically ascertained dose-response relationships could be established as regards electrocardiographic disorders of repolarisation and the systolic time interval (P less than 0.001). Pre-irradiated patients showed more ECG changes (P less than 0.001) and higher PEPI : LVETI values (P less than 0.001) than patients without prior irradiation. There was no general influence of cytostatic treatment on systolic and diastolic blood pressure values. The upper limit of a therapeutic risk in evaluation of the systolic time interval for cardiac monitoring of doxorubicin treatment should be 0.45-0.50 for PEPI : LVETI. Above this borderline value precise cardiac evaluation including invasive methods should be attempted if continuation of treatment is indicated. This regime could help prevent the occurrence of life-threatening cardiac crises during treatment with doxorubicin.

Breast Neoplasms↗

PubMed1983

[Preventable side effects of chemotherapy].

During the last years antineoplastic chemotherapy provided the possibility to cure many patients suffering from a malignant tumor and to improve their quality of life. Like every powerful remedy cytostatic drugs show side effects, which must be taken into consideration. Advantages and risks of cancer chemotherapy have to be considered carefully in each individual treatment schedule. The definition of the upper limit of therapeutic risk for each individual patient in order to avoid life-threatening situations is of principal importance. This can be accomplished by introduction of methods which can measure actual functional conditions and by the definition of a threshold-level in order to establish contraindication. Paul Ehrlich introduced the term "therapeutic index" in antibacterial chemotherapy. This term should express the ratio between risk and benefit of a drug and its application in the still very young field of antineoplastic chemotherapy should be considered. Since every treatment of a patient with cytostatic drugs represents a very significant interference with the patient's life, very strict indication- and and contraindication-criteria have to be applied.

Alopecia↗

PubMed1983

[Pharmacokinetics and acute signs of cardiac toxicity during doxorubicin therapy].

Doxorubicin (Adriamycin) has shown impressive activity in the treatment of a broad spectrum of malignant tumours. Chronic irreversible cardiac myopathy is the usual cumulative dose-limiting toxicity with this anthracycline antibiotic. In this study acute cardiac reactions following doxorubicin infusions (60 mg/m2) were registered by means of ECG Holter monitoring and measurement of systolic time intervals. The PEPI as well as the PEP/LVET ratio were found to be significantly increased, with a peak at 6 hours following drug infusion (p less than 0.001). This observation proves the occurrence of transient myocardial dysfunction during doxorubicin treatment. Pharmacokinetic data showed good correlation between the electrocardiographic changes and the tissue distribution of the drug. Doxorubicin-related ventricular arrhythmias were observed in only 2 out of 6 cases. Repeated acute myocardial damage by doxorubicin infusions is considered to be the cause of chronic cardiomyopathy with long-term administration.

Adult↗

PubMed1983

Indication of reduced doxorubicin-induced cardiac toxicity by additional treatment with antioxidative substances.

The influence of antioxidative substances on doxorubicin-induced cardiac toxicity was studied in C 57 BL mice. Tocopherol (500 mg/kg), glutathione (1000 mg/kg), cysteamine (15 mg/kg) and L-cysteine (1000 mg/kg), injected i.p. 24 h before doxorubicin treatment (15 mg/kg i.p.) were able to reduce malonaldehyde production in cardiac tissues significantly. SH-containing substances with high reducing activity, such as vitamin E, could be a useful tool in clinical trials to prevent doxorubicin induced cardiac damage.

Animals↗

PubMed1983

Evaluation of 99mTc-dichloro bis (1,2-dimethylphosphino) ethane (99mTc-DMPE) for myocardial scintigraphy in man.

99mTc-DMPE was used for myocardial scintigraphy in ten patients with coronary artery disease. As in 201T1 studies regional activity of 99mTc-DMPE was reduced in infarcted myocardium. However, activity accumulation of 99mTc-DMPE in the heart was faint, while that in the liver was prominent. The activity ratio of heart to liver improved with time, whereas that of heart to lung decreased. The scintigraphic quality was considerably worse in 99mTc-DMPE studies than in those with 201Tl, due to high background activity. Also the visualization of the ribs and sternum interfered with the interpretation of the scintigrams. From these results it appears that 201Tl remains still the agent of choice for myocardial perfusion scintigraphy.

Coronary Disease↗

PubMed1983

Noninvasive methods for the early detection of doxorubicin-induced cardiomyopathy.

Ninety-eight female patients (mean age 54 years) who underwent doxorubicin therapy because of metastatic breast cancer were submitted to radionuclide angiography at rest. Left ventricular ejection fractions (LVEFs) were found to decrease significantly with the increasing cumulative doxorubicin dosage. Patients with prior local radiotherapy showed lower LVEFs at the same dosage level than nonirradiated patients, but the difference was not statistically significant. In a further study, 52 patients (mean age 56 years) were followed up regularly for their history and systolic time intervals prior to each doxorubicin treatment course. Before starting treatment, LVEF values were normal in all cases. Fifteen of these patients complained of dyspnea at some time during the treatment period before the critical cumulative dosage level of 550 mg/m2 was reached. Nine of these 15 patients showed an increase of the PEPI:LVETI ratio (greater than or equal to 0.40) and 12 patients a decrease of the LVEF values at rest at the same time. The rest of the patients did not complain of cardiac symptoms and did not show any significant alterations in systolic-time-interval measurements until the borderline dosage level (550 mg/m2) was attained. To evaluate myocardial function with greater accuracy, these 15 patients were submitted to right-heart catheterization and radionuclide angiography at rest and during exercise. As a result, doxorubicin treatment had to be discontinued in three of these patients because of heart failure of stage III or IV and treatment with methyl digoxin and nifedipine was started. In these three patients cardiotonic medication could produce more or less complete cardiac recompensation. We conclude from our findings that signs of stage-III heart failure in radionuclide angiography performed while the patient is at rest and exercising should be regarded as the upper limit of the therapeutic risk, where further doxorubicin treatment is contraindicated. Cardiotonic medication during cytostatic courses should be avoided, however, because the true functional condition of the myocardium could be masked during a potentially cardiotoxic therapy.

Adult↗

PubMed1983

Acute effect of cimetidine and pirenzepine on plasma parathyroid hormone and calcitonin in haemodialyzed patients.

The acute effects of intravenous injection of cimetidine and pirenzepine on plasma iPTH and CT were studied in seven patients on chronic haemodialysis and seven healthy controls. As expected, the resting iPTH and CT levels were significantly higher in patients on RDT than in the healthy subjects. Both drugs decreased to a similar extent the increased plasma iPTH in the patients, but neither was able entirely to normalize the elevated level. The CT concentration in the patients on haemodialysis was significantly decreased by cimetidine but was only moderately reduced by pirenzepine. As neither drug was able to normalize the elevated PTH level in patients on chronic dialysis, it can be assumed that neither used alone would improve signs and symptoms of secondary hyperparathyroidism.

Adult↗

PubMed1983

Thallium-201 imaging after dipyridamole in patients with coronary multivessel disease.

In 60 patients with angiographically documented 2- or 3-vessel disease (at least 70%) thallium-201 images after dipyridamole (0.50 mg/kg bodyweight i.v.) and 4 h later were obtained. In 95% of the patients stress perfusion defects were found. In 48% of the cases scintigraphy correctly diagnosed the presence of multivessel disease, but in only 30% of the patients were all angiographically narrowed vessels detected. The reliability of the method was much higher in the detection of 'infarct stenoses' (96%) than of 'noninfarct stenoses' (46%). The regional sensitivity to assess stenoses of the left anterior descending artery (75%) and right coronary artery (73%) was greater than in stenoses of the left circumflex artery (37%). Thallium-201 scintigraphy after dipyridamole is a sensitive method for diagnosing the presence of coronary artery disease. The diagnostic value is severely limited however by the fact that coronary vasodilation may provoke perfusion abnormalities only in the most ischemic regions, whereas perfusion defects in other areas may not be detectable. Therefore this method does not allow the precise quantitation of all coronary stenoses in the majority of patients.

Adult↗

PubMed1983

Effects of disodium EDTA and calcium infusion on prolactin and thyrotropin responses to thyrotropin-releasing hormone in healthy man.

To determine the impact of induced hypo- and hypercalcemia on TRH (400 micrograms)-stimulated TSH and PRL release, healthy subjects (n = 11) were infused with 5% glucose in water (n = 11), disodium EDTA (n = 11), or calcium gluconate (n = 7). TRH was given as an iv bolus 60 min (5% glucose and EDTA) and 120 min (calcium) after initiation of the respective infusion. Basal plasma concentrations of TSH remained unchanged during induced hypo- and hypercalcemia, whereas those of PRL fell during the latter (P less than 0.05). The mean sum of increments (0-90 min) in PRL and TSH was considerably greater during hypocalcemia than during hypercalcemia (PRL, P less than 0.002; TSH, P less than 0.005). The increments in the plasma hormone concentration above basal after iv TRH were increased compared to those in normocalcemia (PRL, 98.4 +/- 37.9 ng/ml; TSH, 38.9 +/- 11.8 microU/ml) during hypocalcemia [PRL, 128 +/- 47.8 ng/ml (P less than 0.002); TSH, 46.7 +/- 12.8 microU/ml; (P less than 0.005)], but were impaired during hypercalcemia [PRL, 70.1 +/- 27 ng/ml (P less than 0.002); TSH, 28.9 +/- 8.5 microU/ml (P less than 0.025)]. The mean sum of increments in PRL was related to concentrations of both serum calcium (r = -0.59; P less than 0.01) and PTH (r = 0.51; P less than 0.05). A relation was also seen between the incremental responses of TSH and serum calcium (r = -0.52; P less than 0.05), PTH (r = 0.55; P less than 0.01), and phosphorus (r = -0.55; P less than 0.01). We conclude that in healthy man, TRH-mediated release of both PRL and TSH are inversely related to serum calcium concentrations in such a manner that hormone secretion is enhanced by acute hypocalcemia, but blunted by hypercalcemia.

Adult↗