Publications by authors named "Pejchal J"

The GSAG:Ce scintillator represents a promising and cost-effective alternative to the expensive GGAG:Ce. Recent studies have attributed its low light yield to the thermal quenching effect. In this study, we employed the strategy of adding an yttrium (Y) admixture to the GSAG matrix to increase the thermal activation energy of thermal quenching.

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Tacrine is a centrally active non-competitive reversible acetylcholinesterase inhibitor. It also exerts antagonising activity against -methyl-D-aspartate receptors. Tacrine was approved for the treatment of Alzheimer's disease in 1993, but was withdrawn from clinical use in 2013 because of its hepatotoxicity and gastrointestinal side effects.

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Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory loss and behavioral and psychological symptoms of dementia (BPSD). Given that cholinergic neurons are predominantly affected in AD, current treatments primarily aim to enhance cholinergic neurotransmission. However, imbalances in other neurotransmitters, such as γ-aminobutyric acid (GABA), also contribute to AD symptomatology.

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We aimed to prepare novel dibenzo [a,d][7]annulen derivatives that act on N-methyl-d-aspartate (NMDA) receptors with potential neuroprotective effects. Our approach involved modifying the tropane moiety of MK-801, a potent open-channel blocker known for its psychomimetic side effects, by introducing a seven-membered ring with substituted base moieties specifically to alleviate these undesirable effects. Our in silico analyses showed that these derivatives should have high gastrointestinal absorption and cross the blood-brain barrier (BBB).

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Highly porous bioceramic scaffolds are widely used as bone substitutes in many applications. However, the use of bioceramics is often limited to hard tissues due to the risk of potential soft tissue calcification. A further limitation of highly porous bioceramic scaffolds is their poor mechanical stability, manifested by their tendency to break under stress.

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  • Diazepam has been the main treatment for seizures caused by toxic nerve agents since the 1960s, but its limitations have raised concerns, leading to research on alternative medications.
  • Two significant alternatives that have advanced in clinical use are Avizafone and intramuscular midazolam, the latter recently approved by the FDA, offering benefits like rapid action and better solubility.
  • While midazolam shows promise as a more effective treatment for poisoned casualties, its sedative effects pose challenges in determining the right dosage for soldiers in combat situations.
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In this study, we propose novel three-layer composite scintillators designed for the simultaneous detection of different ionizing radiation components. These scintillators are based on epitaxial structures of LuAG and YAG garnets, doped with Ce and Sc ions. Samples of these composite scintillators, containing YAG:Ce and LuAG:Ce single crystalline films with different thicknesses and LuAG:Sc single crystal substrates, were grown using the liquid phase epitaxy method from melt solutions based on PbO-BO fluxes.

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The increasing threat of nuclear incidents and the widespread use of ionizing radiation (IR) in medical treatments underscore the urgent need for effective radiation countermeasures. Despite the availability of compounds such as amifostine, their clinical utility is significantly limited by adverse side effects and logistical challenges in administration. This study focuses on the synthesis and evaluation of novel piperazine derivatives as potential radioprotective agents, with the aim of overcoming the limitations associated with current countermeasures.

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  • N-methyl-D-aspartate receptors (NMDARs) are crucial in various CNS disorders, with current treatments like memantine and ketamine having limitations and side effects.
  • Researchers aimed to create a new NMDAR open-channel blocker, K2060, which displays unique inhibitory properties and stronger effectiveness than existing drugs at inhibiting specific NMDAR subtypes.
  • K2060 showed promising results in a mouse model, reducing excitatory postsynaptic currents significantly and exhibiting a good safety profile, suggesting its potential as a treatment for NMDAR-related CNS disorders.
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Six novel brominated bis-pyridinium oximes were designed and synthesized to increase their nucleophilicity and reactivation ability of phosphorylated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Their pK was valuably found lower to parent non-halogenated oximes. Stability tests showed that novel brominated oximes were stable in water, but the stability of di-brominated oximes was decreased in buffer solution and their degradation products were prepared and characterized.

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  • A-234 is a new generation nerve agent implicated in the poisoning of a former Russian spy in 2018, leading to its inclusion in the Chemical Weapons Convention.
  • Research indicates limited information on A-234's chemical properties, biological effects, and effective treatments, with findings showing the agent is stable but exhibits significant toxicity similar to VX.
  • Current antidotes, especially oximes like HI-6 and methoxime, show minimal effectiveness in reactivating inhibited enzymes, while atropine and diazepam provide better therapeutic outcomes against A-234 lethality.
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  • Tacrine (THA) has been phased out due to safety concerns but is still used as a framework in drug development for its effectiveness against multiple targets, although its potential for liver toxicity is a major concern.
  • Researchers developed 30 new derivatives focusing on minimizing hepatotoxicity while maintaining anticholinesterase properties and targeting specific NMDA receptor subtypes, leading to the identification of two promising candidates, I-52 and II-52.
  • Compound I-52 was highlighted as a lead candidate, demonstrating minimal toxicity, favorable neuroprotective effects in behavioral tests, and lower hepatotoxicity compared to traditional THA-based drugs.
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"Novichok" refers to a new group of nerve agents called the A-series agents. Their existence came to light in 2018 after incidents in the UK and again in 2020 in Russia. They are unique organophosphorus-based compounds developed during the Cold War in a program called Foliant in the USSR.

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Lutetium oxyorthosilicate LuSiO (LSO) and pyrosilicate LuSiO (LPS) activated by Ce or Pr are known to be effective and fast scintillation materials for the detection of X-rays and γ-rays. Their performances can be further improved by co-doping with aliovalent ions. Herein, we investigate the Ce(Pr) → Ce(Pr) conversion and the formation of lattice defects stimulated by co-doping with Ca and Al in LSO and LPS powders prepared by the solid-state reaction process.

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Background: The acetylcholinesterase inhibitor donepezil is administered as a treatment for Alzheimer's disease (AD). However, the appropriate donepezil dosage is still a matter of debate.

Methods: Forty AD patients receiving 10 mg/day of donepezil were randomly divided into four groups based on the time of plasma and cerebrospinal fluid (CSF) sampling: 6 h (n = 5), 12 h (n = 12), 18 h (n = 6) and 24 h (n = 17) after donepezil administration.

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Organophosphorus compounds (OP) are a constant problem, both in the military and in the civilian field, not only in the form of acute poisoning but also for their long-lasting consequences. No antidote has been found that satisfactorily protects against the toxic effects of organophosphates. Likewise, there is no universal cure to avert damage after poisoning.

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Insecticides represent the most crucial element in the integrated management approach to malaria and other vector-borne diseases. The evolution of insect resistance to long-used substances and the toxicity of organophosphates (OPs) and carbamates are the main factors contributing to the development of new, environmentally safe pesticides. In our work, fourteen compounds of 7-methoxytacrine-tacrine heterodimers were tested for their insecticidal effect.

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The JC-1 dye is widely used in apoptosis studies to monitor mitochondrial health. The probe was tested in vitro on two established cell lines and peripheral porcine blood lymphocytes after gamma irradiation (IR) to assess its potential in biodosimetric evaluation. In brief, we stained irradiated and non-irradiated cells with the JC-1 dye to determine the existing changes in mitochondrial membrane potential and monitor cell health through flow cytometry.

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Insulin-like growth factor-1 (IGF-1) stimulates epithelial regeneration but may also induce life-threatening hypoglycemia. In our study, we first assessed its safety. Subsequently, we examined the effect of IGF-1 administered in different dose regimens on gastrointestinal damage induced by high doses of gamma radiation.

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Alzheimer's disease (AD) is one of the most common forms of dementia. Current anti-AD therapeutics exploit the cholinergic hypothesis of its pathophysiology; they aim to inhibit cerebral cholinesterases. K1234 is a novel hybrid molecule derived from Huperzine A and 7-MEOTA-huperzine which shows increased potency in acetylcholinesterase inhibition in vitro compared to the compounds themselves.

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Oxime reactivators are causal antidotes for organophosphate intoxication. Herein, the toxicity, pharmacokinetics, and reactivation effectiveness of o-chlorinated bispyridinium oxime K870 are reported. Oxime K870 was found to have a safe profile at a dose of 30 mg/kg in rats.

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Cucurbit[n]urils are macrocyclic compounds capable of forming host-guest complexes with different molecules. In this study, we focused on cucurbit[7]uril (CB[7]) safety and pharmacokinetics. We investigated CB[7] cytotocixity in human renal cells ACHN using the xCELLigence system.

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Schizophrenia is a serious mental disorder without a fully understood pathomechanism, but which involves dysregulation of neurotransmitters and their receptors. The best option for the management of schizophrenia comprises so-called multi-target ligands, similar to the third generation of neuroleptics. Dopamine type 2 receptors (DRs) are the main target in the treatment of schizophrenia, in particular for mitigation of the positive symptoms.

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