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M Wilk

Publications and source records attributed to M Wilk.

49 records · Page 3Linked to original sources
PubMedDate not supplied

Evaluation of an attenuation correction method for thallium-201 myocardial perfusion tomographic imaging of patients with low likelihood of coronary artery disease.

BACKGROUND: Image artifacts caused by nonuniform photon attenuation are a source of error in interpretation of images during myocardial perfusion single photon emission computed tomography (SPECT). A newly introduced attenuation correction method was evaluated for improvement in image homogeneity during 201Tl SPECT. The method was assessed with a cardiac phantom and in examinations of 42 patients (29 men) with a low likelihood of coronary disease. METHODS AND RESULTS: Simultaneous transmission-emission SPECT was performed with a moving collimated 153Gd line source synchronized with a moving electronic acquisition window for transmission imaging and a novel variable-width electronic exclusion window for emission imaging designed to avoid transmission-to-emission cross talk. The resulting uncorrected and corrected polar maps were analyzed visually and divided into 31 segments for quantitative analysis. Visual analysis of the color-coded mean polar maps showed clear improvement in homogeneity after correction among the phantom, male patients, female patients, and 42 patients combined at stress and redistribution. The male and female mean polar maps showed very little differences in regional count distribution after correction. Quantitative analysis of the mean polar maps showed the following mean segmental counts (%SD) before and after attenuation correction: phantom 88 (9) to 90 (7.5), P = .00005; men at stress 83 (10) to 88 (6), P = .0007, and at redistribution 84 (8) to 88 (6), P = .01; women at stress 86 (7) to 90 (5), P = .0002, and at redistribution 87 (5) to 88 (7), P = .3; patients combined at stress 84 (8) to 88 (6), P = .0004, and at redistribution 85 (7) to 87 (7), P = .03. Inferior/anterior count ratio for men at stress increased after correction from 0.82 to 0.99 and septal/lateral count ratio from 0.94 to 1.02. Inferior/anterior count ratio for men at redistribution increased from 0.86 to 1.06 and septal/lateral count ratio from 0.97 to 1.04. Inferior/anterior count ratio for women at stress increased from 0.95 to 1.03 and septal/lateral count ratio from 0.93 to 1.00. Inferior/anterior count ratio for women at redistribution increased from 1.04 to 1.10, and septal/lateral count ratio decreased from 1.02 to 1.00. CONCLUSION: Improvement in image homogeneity was demonstrated with this attenuation correction method with a cardiac phantom and for patients with low likelihood of coronary artery disease. The slight relative increase in inferior wall counts at redistribution was most likely caused by scatter from the relatively higher liver activity compared with the situation during stress and emphasizes the need for scatter correction. The close similarity in count distribution for the mean male and female polar maps supports use of a sex-independent normal database for quantitative analysis. The reduced variation in corrected images from patient to patient implies increased accuracy for detection of myocardial defects.

Algorithms↗
PubMedDate not supplied

The influence of short-term endurance training on the insulin blood level, binding, and degradation of 125I-insulin by erythrocyte receptors in patients after myocardial infarction.

PURPOSE: This study was directed toward establishing whether and to what extent, short-term endurance training influences the insulin blood level, and the binding and degradation of 125I-insulin by erythrocyte receptors in patients undergoing rehabilitation after myocardial infarction. METHODS: The study was conducted in a group of 60 patients who had had myocardial infarction within the past 1.5 to 3 months and who did not have arterial hypertension and diabetes mellitus. All the patients took a symptom-limited cardiopulmonary exercise test. Before and after the test, venous blood was collected to determine lactic acid and insulin blood levels as well as the binding and degradation of 125I-insulin. The study group was randomized into two subgroups. One subgroup entered into a 3-week in-patient rehabilitation course. The control group was discharged from the hospital and was given no recommendations for physical exercise. The same investigation was repeated 3 weeks later. RESULTS: In the patients (50%) with hyperinsulinemia (insulin resistance index, > 10 microIU/mL), which was detected during the first investigation, insulin blood level decreased from 23.9 +/- 4.4 to 15.0 +/- 1.9 microIU/mL (P < 0.05) after rehabilitation, whereas insulin binding increased from 0.67 +/- 0.05 to 0.85 +/- 0.08 pg 125I/10(11) erythrocytes (P < 0.05). In the control group, which included normal subjects and those with hyperinsulinemia, the results obtained during the first and second investigations showed no statistically significant changes when compared. CONCLUSIONS: The results suggest that a 3-week endurance training period during rehabilitation after myocardial infarction reduces insulin resistance in patients with hyperinsulinemia.

Adult↗
PubMedDate not supplied

[Comparative determination of lipase activity in pharmaceutical preparations].

Lipase activity in various pharmaceuticals has been assayed with different methods expressing the results in different units. Conversion factors enabling comparison of the international and Wallersteins units in FIP units which is current way of pancreatin enzyme activity expression have been calculated. Lipase activity conversion factors are diversified and depend on the type of pharmaceutical preparation containing pancreatic extract. Conversion factors facilitate comparison of lipase activity in different Polish and foreign-made pharmaceutical preparations and proper dosage.

Lipase↗
PubMedDate not supplied

The enkephalin-hydrolytic activity of cerebral and cardiac muscle tissue in Wistar rats with streptozotocin diabetes.

Enkephalin-hydrolytic activity was evaluated in cerebral and cardiac tissue of Wistar rats with experimental streptozotocin-induced diabetes by comparison of the degree of amino acid cleavage from leu-enkephalin in vitro. Ninety days after induction of diabetes the enkephalin-hydrolytic activity was elevated in the cerebral tissue but depressed in the cardiac muscle.

Amino Acids↗