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Background and Objectives: Radiofrequency catheter ablation (RFCA) is a highly successful intervention. By comparing the lesion changes in prostate parenchymal and striated muscle tissues after RFCA with and without cooling, it was possible to assess the correlation between the shape regularity, area, and perimeter of the thermal lesion, and to predict the geometric shape changes of the lesions. Materials and Methods: A standard prostate and striated muscle RFCA procedure was performed on 13 non-purebred dogs in two sessions: no cooling and cooling with 0.1% NaCl solution. Microtome-cut 2–3 µm sections of tissue samples were stained with haematoxylin and eosin and further examined. The quotient formula was employed to evaluate the geometric shape of the damage zones at the ablation site. Results: The extent of injury following RFCA in striated muscle tissue was comparable to that in prostate parenchymal tissue. Regression analysis indicated a strong and positive relationship between area and perimeter in all experimental groups. In the experimental groups of parenchymal tissues with and without cooling, an increase in the area or perimeter of the damage zone corresponded to an increase in the quotient value. A similar tendency was observed in the striated muscle group with cooling. However, in the striated muscle group without cooling, an increase in lesion area or perimeter lowered the quotient value. Standardised regression coefficients demonstrated that in the striated muscle with cooling, the damage zone shape was more determined by area than perimeter. However, in the parenchymal tissue, the perimeter had a more substantial impact on the damage zone shape than the area. Conclusions: The damage area and perimeter have predictive power on the overall shape regularity of damage zone geometry in both striated muscles and parenchymal tissue. This approach is employed to achieve a balance between the need for tumour eradication and the minimisation of ablation-induced complications to healthy tissue. [ABSTRACT FROM AUTHOR]

Abstract Background Bacterial penicillin-binding proteins and β-lactamases (PBP-βLs) constitute a large family of serine proteases that perform essential functions in the synthesis and maintenance of peptidoglycan. Intriguingly, genes encoding PBP-βL homologs occur in many metazoan genomes including humans. The emerging role of LACTB, a mammalian mitochondrial PBP-βL homolog, in metabolic signaling prompted us to investigate the evolutionary history of metazoan PBP-βL proteins. Results Metazoan PBP-βL homologs including LACTB share unique structural features with bacterial class B low molecular weight penicillin-binding proteins. The amino acid residues necessary for enzymatic activity in bacterial PBP-βL proteins, including the catalytic serine residue, are conserved in all metazoan homologs. Phylogenetic analysis indicated that metazoan PBP-βL homologs comprise four alloparalogus protein lineages that derive from α-proteobacteria. Conclusion While most components of the peptidoglycan synthesis machinery were dumped by early eukaryotes, a few PBP-βL proteins were conserved and are found in metazoans including humans. Metazoan PBP-βL homologs are active-site-serine enzymes that probably have distinct functions in the metabolic circuitry. We hypothesize that PBP-βL proteins in the early eukaryotic cell enabled the degradation of peptidoglycan from ingested bacteria, thereby maximizing the yield of nutrients and streamlining the cell for effective phagocytotic feeding.

Anthocyanins are water-soluble pigments providing certain color for various plant parts, especially in edible berries. Earlier these compounds were only known as natural food colorants, the stability of which depended on pH, light, storage temperature and chemical structure. However, due to the increase of the in vitro, in vivo experimental data, as well as of the epidemiological studies, today anthocyanins and their metabolites are also regarded as potential pharmaceutical compounds providing various beneficial health effects on either human or animal cardiovascular system, brain, liver, pancreas and kidney. Many of these effects are shown to be related to the free-radical scavenging and antioxidant properties of anthocyanins, or to their ability to modulate the intracellular antioxidant systems. However, it is generally overlooked that instead of acting exclusively as antioxidants certain anthocyanins affect the activity of mitochondria that are the main source of energy in cells. Therefore, the aim of the present review is to summarize the major knowledge about the chemistry and regulation of biosynthesis of anthocyanins in plants, to overview the facts on bioavailability, and to discuss the most recent experimental findings related to the beneficial health effects emphasizing mitochondria. [ABSTRACT FROM AUTHOR]

KATP channel openers protect ischemic-reperfused myocardium by mimicking ischemic preconditioning, however, the protection mechanisms have not been fully clarified yet. Since the skinned fibers technique gives an opportunity to investigate an entire population of mitochondria in their native milieu, in this study we have investigated the effects of KATP channel openers pinacidil and diazoxide on the respiration rate of rat heart mitochondria in situ, oxidizing physiological substrates pyruvate and malate (6+6 mM). Respiration rates were recorded by the means of Clark-type oxygen electrode in the physiological salt solution (37°C). Our results showed that both pinacidil and diazoxide (60-1250 μM) in a concentration-dependent manner increased pyruvate-malate supported State 2 respiration rate of skinned cardiac fibers (59.1 ± 5.1 nmol O/min/mg fiber dry weight, RCI 2.6 ± 0.2, n=4) by 15-120%. Moreover, diazoxide did not affect, whereas pinacidil (60-1250 μM) decreased the State 3 respiration rate of skinned cardiac fibers (116.6 ± 13.6 nmol O/min/mg fiber dry weight, RCI 2.3 ± 0.2, n=4) by 4-27%. Thus, common effect for both KATP channel openers is uncoupling of pyruvate and malate oxidizing mitochondria in skinned cardiac fibers, whereas pinacidil under same conditions also inhibits mitochondrial respiratory chain. Since mitochondria in situ resemble to the great extent mitochondria in vivo, our results suggest that uncoupling and/or respiratory chain inhibition could play a role in the cardioprotection by KATP channel openers. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The inhibition of ATP-ase or the impairment of ADP/ATP transport is suggested to be responsible for the cardioprotective effects of KATP channel openers. In this study, we investigated the ability of KATP channel openers to affect K+ and H+ flux to the matrix of rat heart mitochondria as well as permeability of mitochondrial membranes for ADP under mildly acidic (pH 6.8) conditions. K+ and H+ flux to the mitochondrial matrix was registered spectrophotometrically as the swelling of non-respiring mitochondria at 540 nm in the KNO3 and NH4NO3 medium. The apparent KM for ADP of mitochondria was estimated from the least-squares fit to the Michaelis-Menten equation. The results showed that the KATP channel openers diazoxide and pinacidil could activate potassium ion and proton flux to the mitochondrial matrix both under normal (pH 7.4) and mildly acidic (pH 6.8) conditions. Mild acidosis increased the apparent KM for ADP of mitochondria two times (up to 60.6 ± 3.4 µM) as compared to control (33.0 ± 3.2 µM). The KATP channel opener diazoxide (100 µM) increased the apparent KM for ADP by 40% under control and by 30% under mildly acidic conditions. Our results suggest that KATP channel openers could suppress the ADP/ATP exchange during ischemia and thus promote preservation of ATP in cardiomyocytes. [ABSTRACT FROM AUTHOR]

We have searched through plant databases for nucleotide and protein sequences sharing a significant similarity to bacterial serine β-lactamases and metazoan LACTB. The search resulted in the identification of novel serine β-lactamase homologues in both Gymno- and Angiosperms. However, unlike bacterial β-lactamases and metazoan LACTB, plant homologues are dual domain proteins composed of an N-terminal ABC1 domain containing serine / threonine protein kinase motifs, followed by a C-terminal β-lactamase domain containing the active site motifs present in all serine β-lactamases. Multiple sequence alignments and secondary structure modelling of the β-lactamase domain revealed conserved regions that correspond to structural elements required for the serine protease active center formation. On the basis of sequence homology and secondary structure conservation, we propose that the chimeric plant protein is involved in apoptotic processes through its serine protease and serine / threonine protein kinase activity. [ABSTRACT FROM AUTHOR]

During the last decades, one of the most common nondrug therapies used for patients cardiac arrhythmia treatment is a controlled thermal destruction of certain myocardial structures and tissues. However, the investigations of small microstructural changes of thermal tissue destruction are neglected. This study investigated the effect of radiofrequency ablation with active electrode cooling, on dog thigh muscle damage character and size. Three experiment sessions were performed on thirteen mongrel dogs. The first radiofrequency ablation session was done without cooling. In the second session the electrode was cooled with a 0.1% NaCl solution and during the third session, cooling was made with a 0.9% NaCl solution. In all cases the duration of ablation was 30 s and the power was 40 W. Lastly, the calculations of a theoretical model were accomplished. Our experimental results show that the strongest impact of the ablation on tissue damage was observed in the first session, medium in the second session and the lowest in the third session. The average damaged area of ablated tissue was the largest in the first session, medium in the third session and the smallest in the second session (p<0.05). The highest temperature on the surface of the heated tissues at the ablating electrode contact site during the ablation procedure was measured in the first session, medium in the second session and smallest in the third session. Experimental results and theoretical calculations allow making an assumption that the different concentrations of cooling solution influence the ablating tissue damage size and character, due to the redistribution of electric field strength lines. The examination of histological preparations revealed that in the tissues affected by the ablation procedure the enclosed ,/ing" shape stripe of damaged area is detectable. [ABSTRACT FROM AUTHOR]