The process of platelet aggregation is often influenced by several factors including sex and age. A literature review confirmed the existence of sex-related differences in platelet aggregation. Although 68 out of 78 papers found such differences, there are still some controversies regarding these differences, which can be due to multiple factors (age, trigger, concomitant disease, sample handling, etc.). These outcomes are discussed in line with novel results obtained from a local study, in which blood samples from a total of 53 overall healthy women and men with ages ranging from 20 to 66 years were collected. Aggregation was induced with seven different triggers (ristocetin, thrombin receptor activating peptide 6 [TRAP-6], arachidonic acid [AA], platelet-activating factor 16 [PAF-16], ADP, collagen, or thromboxane A2 analog U-46619) ex vivo. In addition, three FDA-approved antiplatelet drugs (vorapaxar, ticagrelor, or acetylsalicylic acid [ASA]) were also tested. In general, women had higher aggregation responses to some agonists (ADP, TRAP), as well as lower benefit from inhibitors (ASA, vorapaxar). The aggregatory responses to AA and TRAP decreased with age in both sexes, while responses to ADP, U-46619, and PAF were affected by age only in women. In conclusion, more studies are needed to decipher the biological importance of sex-related differences in platelet aggregation in part to enable personalized antiplatelet treatment.

• MeSH
• adenosindifosfát farmakologie   MeSH
• agregace trombocytů * MeSH
• Aspirin terapeutické užití   MeSH
• inhibitory agregace trombocytů * terapeutické užití   MeSH
• kyselina 15-hydroxy-11 alfa,9 alfa-(epoxymethano)prosta-5,13-dienová farmakologie   MeSH
• kyselina arachidonová farmakologie   MeSH
• laktony farmakologie   MeSH
• lidé MeSH
• trombocyty MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

PURPOSE: The incidence of acute myocardial infarctions (AMI) shows circadian variation typically peaking during morning hours with a decline at night. However, this variation does not occur in patients with diabetes mellitus (DM). The night's decline of AMI may be partially explained by melatonin-related platelet inhibition. Whether this effect is absent in diabetic patients is unknown. The aim was to study the effect of melatonin on in-vitro platelet aggregation in healthy individuals and patients with type 2 DM. METHODS: Platelet aggregation was measured in blood samples from healthy individuals (n = 15) and type 2 DM patients (n = 15) using multiple electrode aggregometry. Adenosine diphosphate (ADP), arachidonic acid (ASPI) and thrombin (TRAP) were used as agonists. Aggregability for each subject was tested after adding melatonin in two concentrations. RESULTS: In healthy individuals, melatonin inhibited platelet aggregation in both higher (10-5 M) and lower concentrations (10-9 M) induced by ADP, ASPI, and TRAP (p < 0.001, p = 0.002, p = 0.029, respectively). In DM patients, melatonin did not affect platelet aggregation in both concentrations induced by ADP, ASPI, and TRAP. Melatonin decreased platelet aggregation induced by ADP, ASPI, and TRAP significantly more in healthy individuals compared to patients with DM. (p = 0.005, p = 0.045 and p = 0.048, respectively). CONCLUSION: Platelet aggregation was inhibited by melatonin in healthy individuals. In-vitro antiplatelet effect of melatonin in type 2 DM patients is significantly attenuated.

• MeSH
• adenosindifosfát farmakologie   MeSH
• agregace trombocytů fyziologie   MeSH
• diabetes mellitus 2. typu * farmakoterapie   MeSH
• infarkt myokardu * MeSH
• inhibitory agregace trombocytů farmakologie   terapeutické užití   MeSH
• lidé MeSH
• melatonin * farmakologie   terapeutické užití   MeSH
• trombocyty fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) support is often associated with bleeding complications caused by secondary or primary hemostasis pathology. However, there are limited data investigating primary hemostasis using Multiplate aggregometry with specific diagnostics tests for vWF (von Willebrand factor) deficiency. AIMS: The aim of this study was to find out whether short-term ECMO produces the pathology of primary hemostasis that is detected by Multiplate aggregometry and to investigate the pathology of vWF. METHODS: In this study, blood samples of 20 patients undergoing lung transplantations with short-term perioperative ECMO support were analyzed. The multimeric structure, the levels of von Willebrand factor antigen (vWF), ristocetin cofactor (RCo), collagen-binding protein (CB), and the results of multiple electrode aggregometry RISTO (ristocetin), ADP (adenosine diphosphate), ASPI (Aspirin®; arachidonic acid), and TRAP (thrombin receptor activating peptide) tests were compared to the samples obtained before and after ECMO support. RESULTS: The Multiplate ADP and RISTO tests showed the presence of significant pathology in primary hemostasis after surgery (p < 0.05), suggesting the presence of acquired platelet dysfunction. Although the RISTO tests suggest the presence of acquired vWF deficiency, laboratory tests for vWF antigen and RCo and CB tests showed an increase in this case. The multimeric structure of vWF did not show clinically significant deterioration. CONCLUSIONS: Multiple aggregometry ADP, ASPI, and TRAP tests seem to be able to detect primary hemostasis pathology (platelets aggregation and adhesion pathology) that is present during short-term perioperative ECMO support in lung transplantation procedures. Interestingly, RISTO tests seem to be more suitable for the diagnosis of platelet dysfunction than the diagnosis of acquired vWF deficiency in this situation.

• MeSH
• adenosindifosfát MeSH
• hemostáza MeSH
• lidé MeSH
• mimotělní membránová oxygenace * škodlivé účinky   metody   MeSH
• retrospektivní studie MeSH
• trombocytopatie * MeSH
• von Willebrandova nemoc * MeSH
• von Willebrandův faktor metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• pozorovací studie MeSH

Most in vivo 31P MR studies are realized on 3T MR systems that provide sufficient signal intensity for prominent phosphorus metabolites. The identification of these metabolites in the in vivo spectra is performed by comparing their chemical shifts with the chemical shifts measured in vitro on high-field NMR spectrometers. To approach in vivo conditions at 3T, a set of phantoms with defined metabolite solutions were measured in a 3T whole-body MR system at 7.0 and 7.5 pH, at 37 °C. A free induction decay (FID) sequence with and without 1H decoupling was used. Chemical shifts were obtained of phosphoenolpyruvate (PEP), phosphatidylcholine (PtdC), phosphocholine (PC), phosphoethanolamine (PE), glycerophosphocholine (GPC), glycerophosphoetanolamine (GPE), uridine diphosphoglucose (UDPG), glucose-6-phosphate (G6P), glucose-1-phosphate (G1P), 2,3-diphosphoglycerate (2,3-DPG), nicotinamide adenine dinucleotide (NADH and NAD+), phosphocreatine (PCr), adenosine triphosphate (ATP), adenosine diphosphate (ADP), and inorganic phosphate (Pi). The measured chemical shifts were used to construct a basis set of 31P MR spectra for the evaluation of 31P in vivo spectra of muscle and the liver using LCModel software (linear combination model). Prior knowledge was successfully employed in the analysis of previously acquired in vivo data.

• MeSH
• adenosindifosfát metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• fosfatidylcholiny metabolismus   MeSH
• fosfatidylethanolaminy metabolismus   MeSH
• fosfáty metabolismus   MeSH
• fosfor metabolismus   MeSH
• játra metabolismus   MeSH
• kosterní svaly metabolismus   MeSH
• lidé MeSH
• nukleární magnetická rezonance biomolekulární * MeSH
• pilotní projekty MeSH
• software * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

The RAD51 recombinase assembles as helical nucleoprotein filaments on single-stranded DNA (ssDNA) and mediates invasion and strand exchange with homologous duplex DNA (dsDNA) during homologous recombination (HR), as well as protection and restart of stalled replication forks. Strand invasion by RAD51-ssDNA complexes depends on ATP binding. However, RAD51 can bind ssDNA in non-productive ADP-bound or nucleotide-free states, and ATP-RAD51-ssDNA complexes hydrolyse ATP over time. Here, we define unappreciated mechanisms by which the RAD51 paralog complex RFS-1/RIP-1 limits the accumulation of RAD-51-ssDNA complexes with unfavorable nucleotide content. We find RAD51 paralogs promote the turnover of ADP-bound RAD-51 from ssDNA, in striking contrast to their ability to stabilize productive ATP-bound RAD-51 nucleoprotein filaments. In addition, RFS-1/RIP-1 inhibits binding of nucleotide-free RAD-51 to ssDNA. We propose that 'nucleotide proofreading' activities of RAD51 paralogs co-operate to ensure the enrichment of active, ATP-bound RAD-51 filaments on ssDNA to promote HR.

• MeSH
• adenosindifosfát farmakologie   MeSH
• adenosintrifosfát farmakologie   MeSH
• Caenorhabditis elegans metabolismus   MeSH
• druhová specificita MeSH
• fluorescence MeSH
• interferometrie MeSH
• jednovláknová DNA metabolismus   MeSH
• nukleotidy metabolismus   MeSH
• proteiny Caenorhabditis elegans metabolismus   MeSH
• rekombinasa Rad51 chemie   metabolismus   MeSH
• sekvenční homologie aminokyselin * MeSH
• stabilita proteinů účinky léků   MeSH
• vazba proteinů účinky léků   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

There is inconsistent information regarding the size effects of exogenously given hyaluronan on its in vivo fate. The data are often biased by the poor quality of hyaluronan and non-ideal labelling strategies used for resolving exogenous/endogenous hyaluronan, which only monitor the label and not hyaluronan itself. To overcome these drawbacks and establish the pharmacokinetics of intravenous hyaluronan in relation to its Mw, 13C-labelled HA of five Mws from 13.6-1562 kDa was prepared and administered to mice at doses 25-50 mg kg-1. The elimination efficiency increased with decreasing Mw. Low Mw hyaluronan was rapidly eliminated as small hyaluronan fragments in urine, while high Mw hyaluronan exhibited saturable kinetics and complete metabolization within 48 h. All tested Mws exhibited a similar uptake by liver cells and metabolization into activated sugars. 13C-labelling combined with LC-MS provides an excellent approach to elucidating in vivo fate and biological activities of hyaluronan.

• MeSH
• cesty eliminace léčiva MeSH
• chrupavka metabolismus   MeSH
• cyklická ADP-ribosa metabolismus   MeSH
• intravenózní podání MeSH
• izotopové značení metody   MeSH
• izotopy uhlíku chemie   metabolismus   farmakokinetika   MeSH
• kosti a kostní tkáň metabolismus   MeSH
• kyselina hyaluronová chemie   metabolismus   farmakokinetika   MeSH
• molekulová hmotnost MeSH
• myši inbrední BALB C MeSH
• tkáňová distribuce MeSH
• uridindifosfát-N-acetylglukosamin metabolismus   MeSH
• uridindifosfátglukosa metabolismus   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tuberculosis (TB) remains one of the major health concerns worldwide. Mycobacterium tuberculosis (Mtb), the causative agent of TB, can flexibly change its metabolic processes during different life stages. Regulation of key metabolic enzyme activities by intracellular conditions, allosteric inhibition or feedback control can effectively contribute to Mtb survival under different conditions. Phosphofructokinase (Pfk) is one of the key enzymes regulating glycolysis. Mtb encodes two Pfk isoenzymes, Pfk A/Rv3010c and Pfk B/Rv2029c, which are differently expressed upon transition to the hypoxia-induced non-replicating state of the bacteria. While pfkB gene and protein expression are upregulated under hypoxic conditions, Pfk A levels decrease. Here, we present biochemical characterization of both Pfk isoenzymes, revealing that Pfk A and Pfk B display different kinetic properties. Although the glycolytic activity of Pfk A is higher than that of Pfk B, it is markedly inhibited by an excess of both substrates (fructose-6-phosphate and ATP), reaction products (fructose-1,6-bisphosphate and ADP) and common metabolic allosteric regulators. In contrast, synthesis of fructose-1,6-bisphosphatase catalyzed by Pfk B is not regulated by higher levels of substrates, and metabolites. Importantly, we found that only Pfk B can catalyze the reverse gluconeogenic reaction. Pfk B thus can support glycolysis under conditions inhibiting Pfk A function.

• MeSH
• adenosindifosfát metabolismus   farmakologie   MeSH
• adenosintrifosfát metabolismus   farmakologie   MeSH
• alosterická regulace MeSH
• bakteriální proteiny antagonisté a inhibitory   metabolismus   MeSH
• enzymová indukce MeSH
• fosfofruktokinasy antagonisté a inhibitory   metabolismus   MeSH
• fruktosadifosfáty biosyntéza   farmakologie   MeSH
• fruktosafosfáty metabolismus   farmakologie   MeSH
• glukoneogeneze MeSH
• glykolýza MeSH
• hexosafosfáty metabolismus   MeSH
• izoenzymy antagonisté a inhibitory   metabolismus   MeSH
• katalýza MeSH
• kinetika MeSH
• kyslík farmakologie   MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• Mycobacterium tuberculosis účinky léků   enzymologie   MeSH
• pyruvátkinasa metabolismus   MeSH
• rekombinantní proteiny metabolismus   MeSH
• substrátová specifita MeSH
• zpětná vazba fyziologická MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

Neurodegeneration is a common hallmark of individuals with hereditary defects in DNA single-strand break repair; a process regulated by poly(ADP-ribose) metabolism. Recently, mutations in the ARH3 (ADPRHL2) hydrolase that removes ADP-ribose from proteins have been associated with neurodegenerative disease. Here, we show that ARH3-mutated patient cells accumulate mono(ADP-ribose) scars on core histones that are a molecular memory of recently repaired DNA single-strand breaks. We demonstrate that the ADP-ribose chromatin scars result in reduced endogenous levels of important chromatin modifications such as H3K9 acetylation, and that ARH3 patient cells exhibit measurable levels of deregulated transcription. Moreover, we show that the mono(ADP-ribose) scars are lost from the chromatin of ARH3-defective cells in the prolonged presence of PARP inhibition, and concomitantly that chromatin acetylation is restored to normal. Collectively, these data indicate that ARH3 can act as an eraser of ADP-ribose chromatin scars at sites of PARP activity during DNA single-strand break repair.

• MeSH
• adenosindifosfát ribosa chemie   MeSH
• chromatin chemie   MeSH
• fibroblasty MeSH
• genový knockout MeSH
• glykosidhydrolasy genetika   MeSH
• HEK293 buňky MeSH
• histony chemie   MeSH
• jednořetězcové zlomy DNA * MeSH
• lidé MeSH
• mutace * MeSH
• nádorové buněčné linie MeSH
• neurodegenerativní nemoci genetika   MeSH
• oprava DNA * MeSH
• protein XRCC1 genetika   MeSH
• regulace genové exprese MeSH
• viabilita buněk MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We assessed the contribution of CYP2C19 and CYP3A4 metabolic activity to the ADP-induced platelet aggregation 1h and 24h after a loading dose of 60 mg prasugrel or 180 mg ticagrelor in patients with ST-elevation myocardial infarction (STEMI). Further, we assessed the contribution of CYP2C19 polymorphisms and medication to the CYP enzymatic activity.Patients with STEMI were randomly assigned to the treatment with prasugrel (n = 51) or ticagrelor (n = 46). Metabolic activity of CYP2C19 and CYP3A4 was assessed by the rate of 5-hydroxylation and sulfoxidation of lansoprazole. Further, patients were genotyped for CYP2C19 *2 and *17 alleles.In prasugrel-treated patients, high ADP-induced platelet reactivity 1h after the loading dose positively correlated with 5OH-lansoprazole/lansoprazole ratio (r = 0.44, p = 0.002), a marker of CYP2C19 metabolic activity, and negatively with lansoprazole-sulfone/lansoprazole ratio, which reflects CYP3A4 metabolic activity (r = -0.35, p = 0.018).CYP2C19 poor metabolizers had lower 5OH-lansoprazole/lansoprazole ratio and higher lansoprazole-sulfone/lansoprazole ratio, but without any effect on the ADP-induced platelet reactivity. The treatment with amiodarone, a CYP3A4 inhibitor, influenced neither the metabolic ratios nor the ADP-induced platelet reactivity.The CYP3A4 and CYP2C19 metabolic activity is associated with ADP-induced platelet reactivity in prasugrel-treated, but not ticagrelor-treated patients with STEMI.

• MeSH
• adenosindifosfát metabolismus   MeSH
• cytochrom P-450 CYP3A metabolismus   MeSH
• cytochrom P450 CYP2C19 metabolismus   MeSH
• infarkt myokardu s elevacemi ST úseků farmakoterapie   MeSH
• lidé MeSH
• prasugrel hydrochlorid farmakologie   terapeutické užití   MeSH
• ticagrelor farmakologie   terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Mitochondria and oxidative phosphorylation (OXPHOS) are emerging as intriguing targets for the efficient elimination of cancer cells. The specificity of this approach is aided by the capacity of non-proliferating non-cancerous cells to withstand oxidative insult induced by OXPHOS inhibition. Recently we discovered that mitochondrial targeting can also be employed to eliminate senescent cells, where it breaks the interplay between OXPHOS and ATP transporters that appear important for the maintenance of mitochondrial morphology and viability in the senescent setting. Hence, mitochondria/OXPHOS directed pharmacological interventions show promise in several clinically-relevant scenarios that call for selective removal of cancer and senescent cells.

• MeSH
• adenosindifosfát metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• biologický transport MeSH
• buněčná smrt MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• nádory metabolismus   patologie   MeSH
• oxidativní fosforylace MeSH
• proliferace buněk MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• stárnutí buněk * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH