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Biomedical subjects

P Szymański

Publications and source records attributed to P Szymański.

7 recordsLinked to original sources
PubMed2006

New tacrine-hydrazinonicotinamide hybrids as acetylcholinesterase inhibitors of potential interest for the early diagnostics of Alzheimer's disease.

The syntheses and the preliminary results of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by an affinity series of tacrine-hydrazinonicotinamide hybrids are described. These molecules were prepared by condensation of tacrine analogues with the hydrazine nicotinate moiety (HYNIC). Derivatives 6a and 6b showed lower activity than the model tacrine, while compounds 6c and 6d showed the strongest affinity to AChE. All the tested compounds exhibited lower affinity for BChE than tacrine. Alzheimer disease (AD) is characterised by a deficit of acetylcholinesterase, and these new compounds, as ligands for 99mTc complexes, are potential radiopharmaceuticals for an early diagnosis of Alzheimer's disease.

Acetylcholinesterase↗
PubMed1999

The relationship between diastolic function of the left ventricle and QT dispersion in patients with myocardial infarction.

Lack of synchronicity concerns not only the electrical but also the mechanical function of the left ventricle and causes impaired ventricular filling. To our knowledge a direct association between electrical dispersion and impairment of left ventricular filling has not been reported. The study group comprised 71 patients with myocardial infarction. Echocardiographic Doppler studies and QT dispersion measurements from standard 12-lead electrocardiograms were performed during the second week of hospitalization. The study population was divided into high, intermediate and low QT dispersion groups. Differences in the left ventricular filling parameters between high and low QT dispersion groups were assessed. Patients with high QT dispersion had larger end-diastolic volume (134+/-31 vs. 107+/-19 ml; P=0.049) and tended to have shorter E-wave deceleration time (155+/-18 vs. 175+/-20 ms; P=0.056) compared with patients with low QT dispersion. There was a negative correlation between E-wave deceleration time and QT dispersion (r=-0.248; P=0.05). We conclude that greater dispersion of repolarization is accompanied by changes in the left ventricular diastolic geometry and more 'restrictive' filling. The hypothesis that left ventricular filling abnormalities are caused by increased electrical dispersion deserves further study, especially under controlled, experimental conditions.

Aged↗
PubMed1997

Modelling cardiac patient set residuals using rough sets.

Many medical studies deal with the assessment of the prognostic or diagnostic power of some particular test with respect to some particular medical condition. However, even though a test is deemed to be powerful in this respect, the test may not be strictly needed to perform for everyone. If the test is costly or invasive, this issue is of particular interest. This paper presents a methodology based on rough set theory and Boolean reasoning that can be used to identify those patients for whom performing the test is redundant or superfluous. Furthermore, the methodology enables one to automatically construct a set of descriptive and minimal if-then rules that model the patient group in need of the test. A reanalysis of a previously published real-world dataset of patients with chest pain is used as a case study.

Coronary Disease↗
PubMed1993

[Cardiac arrhythmias during extracorporeal shock wave lithotripsy].

Holter monitoring was performed in 55 patients (24 women, 31 men), mean age 50.7 +/- 11.3 who underwent ECG-triggered extracorporeal shock wave lithotripsy (ESWL). Patients were divided into two groups A--30 with history of cardiac disease and B--25 control. The heart rate was significantly higher before and after ESWL in the first group. The number of premature ventricular contractions was higher during ESWL in the same group. No other cardiac complication was observed.

Adult↗
PubMed1991

Dimensions of the mylohyoid muscle in human fetuses.

In 67 fetuses (9-35 weeks) the measurements of the mylohyoid muscle were made. The length of mandibular origin of the muscle increases proportionally to increase in length of the mandible and it is particularly evident beginning from 16th week on.

Embryonic and Fetal Development↗
PubMed1987

Hyperthyroidism affects the activity of a cAMP-dependent protein kinase and protein phosphorylation in heart sarcolemma.

We have investigated the effect of thyroxine administration on the cAMP related systems in heart sarcolemma. Hyperthyroidism produces an increase in the number of beta-receptors and enhances in situ the phosphorylation of some sarcolemmal proteins, in particular the 55 kDa peptide. On the other hand, the activity of a membrane-bound cAMP-dependent protein kinase is considerably lower in sarcolemma obtained from animals receiving the hormone. We suggest that the thyroxine-induced alteration in beta-receptors elevates the content of cAMP in the cell which, in turn, evokes a transient dissociation of the catalytic subunit of a cAMP-dependent kinase from the regulatory subunit embeded in the membrane.

Animals↗