Biomedical subjects

Jacek Kowalczyk

Publications and source records attributed to Jacek Kowalczyk.

3 recordsLinked to original sources

PubMed2006

Current developments in microvolt T-wave alternans.

Microvolt T-wave alternans (MTWA), the beat-to-beat fluctuation in T wave amplitude and morphology, is closely linked to vulnerability to ventricular arrhythmias in various experimental and clinical conditions. Clinically, MTWA is most commonly measured using the spectral method, although non-spectral methods for its assessment from ambulatory electrocardiographical recordings also have been developed. Recent studies suggest that the quantitative assessment of TWA may also be clinically relevant. The standardisation of the criteria for abnormal MTWA test still needs to be completed. The expansion of indications for implantable cardioverter-defibrillator (ICD) therapy following the positive results of the MADIT-II and SCD-HeFT trials might have unacceptable economic and medical consequences, and therefore new tests are needed to better discriminate patients who will and will not benefit from ICD implantation. A recent meta-analysis of MTWA studies revealed an overall positive predictive value for arrhythmic events of 19.3%, negative predictive value of 97.2%, and 3.77% univariate relative risk of arrhythmic events. The negative predictive value of MTWA in MADIT-II type patients has been reported to be 97.5%. The predictive value of the test varied significantly in different patient population. Current data support the use of MTWA testing for evaluation of patients with low ejection fraction who are considered for ICD implantation. The independence of the prognostic value of MTWA from other clinical and electrophysiological variables needs further confirmation.

Journal Article↗

PubMed2003

[Heat-shock proteins in myocardial ischemia].

Heat-shock proteins (HSP) are a group of highly conserved proteins, which production is induced as a intracellular response to different kinds of stresses. They are also included in the group of chaperones, which are involved in protein folding and refolding in the cells, stabilising of macromolecular structure and repairing of denatured proteins or promoting their degradation when damages are too advanced. Because of protective role of HSP on the cellular level, a lot of studies is focused on the place of HSP in cardioprotection. The exact mechanism of this activity is still unknown. The experiments provided convincing proofs that cardiomyocytes which were subjected to hyperthermia or many other stress factors were reacting increased synthesis of HSP what guaranteed protection against further, stronger episodes of different stresses. The problem, which is still actual, is finding the possibility of taking advantage of cardioprotective properties of HSP in the treatment. Such a situation is due to lack of noninvasive methods of inducing HSP expression. The present study is a kind of review of literature taking up this problem, starting with protocols using hyperthermia, through the pharmacological therapy and ending with molecular techniques and genetic engineering.

Heat-Shock Proteins↗

PubMed2002

[Vascular endothelial growth factor and its application in therapy of cardiovascular diseases].

Vascular endothelial growth factor (VEGF) is a glycoprotein with a molecular weight of about 45,000 and it is an endothelial cell specific mitogen. The essential function of VEGF is induction of angiogenesis and stimulation of endothelial proliferation. Since few years there are some clinical trials using VEGF in the field of: stimulation of reendothelialization and prevention of restenosis after revascularization, therapy of peripheral vascular disorders leading to ischemic limb, therapy of ischemic heart disease through neoangiogenesis. First group of mentioned studies is making use of ability of VEGF to stimulate the endothelial proliferation and accelerate its regeneration. Second and third group of clinical trials is taking advantage of angiogenic activity of VEGF, which leads to collateral vessel development and enhancement of ischemic area perfusion. There are also studies in the field of VEGF gene therapy, which had a big advantage over treatment with VEGF-protein because it is stimulating VEGF production for even few weeks. Besides there are new ways of drug administration. The specialist of many different medicine disciplines (not only of cardiovascular diseases) are interested in VEGF. The results of their studies are pointing at purposefulness of continuing them and making that VEGF is having bigger and bigger importance in medicine.

Cardiovascular Diseases↗