Cryptococcus neoformans is an encapsulated yeast that can cause cryptococcosis and cryptococcal meningitis, which conventional treatment involves antifungal drugs such as polyenes, flucytosine, azoles, and their combinations. However, the high cost, toxicity, and increase in fungi resistance to antifungal agents stimulate the search for therapeutic strategies such as drug repurposing and combination therapy. This study evaluated the activity of the antihypertensive verapamil (VEH) alone and combined with amphotericin B (AmB) against C. neoformans. VEH exhibited antifungal activity against C. neoformans with minimum inhibitory concentration and minimum fungicidal concentration of 118 µg per mL. The combination of VEH and AmB exhibited synergism, reducing at least eightfold both drugs' concentrations. Moreover, the combination decreased the size and glucuronoxylomannnan content of C. neoformans capsule. However, no difference was observed in ergosterol levels of C. neoformans after treatment with VEH and AmB in combination. Altogether, VEH in combination with AmB exhibits potential as a candidate as for the development of anti-cryptococcal drug.

• Klíčová slova
• Antifungal, Capsule, Cryptococcus neoformans, Synergism, Verapamil,
• MeSH
• amfotericin B farmakologie   terapeutické užití   MeSH
• antifungální látky farmakologie   terapeutické užití   MeSH
• Cryptococcus neoformans * MeSH
• flucytosin farmakologie   terapeutické užití   MeSH
• kryptokokóza * farmakoterapie   mikrobiologie   MeSH
• mikrobiální testy citlivosti MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• amfotericin B MeSH
• antifungální látky MeSH
• flucytosin MeSH

Gene-directed enzyme/prodrug therapy represents one of the experimental treatment approaches. The system based on conversion of nontoxic prodrug 5-fluorocytosine to chemotherapeutic 5-fluorouracil by cytosine deaminase or fusion cytosine deaminase::uracil phosphoribosyl transferase belongs to the most frequently used. The detailed analysis of 5-fluorocytosine, 5-fluorouracil and its metabolites enables to understand various responses of tumour cells to treatment as well as mechanisms of resistance. A fast, sensitive and accurate methods based on liquid chromatography with high-resolution mass spectrometry (LC-HRMS) for the identification and quantification of 5-fluorocytosine, 5-fluorouracil and its major metabolites were developed. Two different hybrid high-resolution mass spectrometers sufficient for study of metabolic pathways were used. The LC-ESI IT-TOF MS method was successfully used for identification of 5-fluorocytosine, 5-fluorouracil and its metabolites in complex biological matrices (mesenchymal stromal cells and tumour cells media) and for confirmation of the metabolic conversion of 5-fluorocytosine even in chemoresistant tumour cells media samples. For quantification, the LC-HESI QExactive MS method was developed and validated. The developed method demonstrated a very good linear range for 5-fluorocytosine from 1 ng/mL to 1000 ng/mL and for its major metabolites from 5 ng/mL to 1000 ng/mL. The limits of detection and limits of quantification ranged from 1.1 to 26 ng/mL and from 3.6 to 87 ng/mL, respectively. Both developed methods confirmed the ability of gene-directed enzyme prodrug therapy to metabolically convert 5-fluorocytosine to 5-fluorouracil and its major metabolites in real samples of tumour cell media and mesenchymal stromal cells.

• Klíčová slova
• 5-fluorouracil, Cancer therapy, Chemotherapeutics, High resolution mass spectrometry, Metabolites,
• MeSH
• chromatografie kapalinová MeSH
• cytosindeaminasa MeSH
• flucytosin * MeSH
• fluoruracil MeSH
• hmotnostní spektrometrie MeSH
• prekurzory léčiv * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytosindeaminasa MeSH
• flucytosin * MeSH
• fluoruracil MeSH
• prekurzory léčiv * MeSH

Chemotherapeutics are pharmaceutical compounds the occurrence of which in the environment is of growing concern because of the increase in treatments against cancer diseases. They can reach the aquatic ecosystems after passing through wastewater treatment plants without complete removal. One of the most frequently used chemotherapeutics is 5-fluorouracil which exhibits a strong cytostatic effect. In this paper, an analytical methodology was developed, validated, and applied to determine 5-fluorouracil, its precursor, 5-fluorocytosine, and its major active metabolite, 5-fluorouridine, in hospital wastewater samples. Due to the expected low concentrations after dilution and interferences present in such a complex matrix, a very selective and sensitive detection method is required. Moreover, an extraction method must be implemented prior to the determination in order to purify the sample extract and preconcentrate the target analytes at micrograms per liter concentration levels. Solid-phase extraction followed by liquid chromatography with tandem mass spectrometry was the combination of choice and all included parameters were studied. Under optimized conditions for wastewater samples analysis, recoveries from 63 to 108% were obtained, while intraday and interday relative standard deviations never exceeded 20 and 25%, respectively. Limits of detection between 61 and 620 ng/L were achieved. Finally, the optimized method was applied to samples from hospital wastewater effluents.

• Klíčová slova
• cytostatic compounds, sample pretreatment, tandem mass spectrometry, wastewater samples,
• MeSH
• chemické látky znečišťující vodu analýza   MeSH
• extrakce na pevné fázi MeSH
• flucytosin analýza   MeSH
• fluoruracil analýza   MeSH
• molekulární struktura MeSH
• nemocnice * MeSH
• odpadní voda chemie   MeSH
• tandemová hmotnostní spektrometrie MeSH
• uridin analogy a deriváty   analýza   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 5-fluorouridine MeSH Prohlížeč
• chemické látky znečišťující vodu MeSH
• flucytosin MeSH
• fluoruracil MeSH
• odpadní voda MeSH
• uridin MeSH

The natural behavior of mesenchymal stem cells (MSCs) and their exosomes in targeting tumors is a promising approach for curative therapy. Human tumor tropic mesenchymal stem cells (MSCs) isolated from various tissues and MSCs engineered to express the yeast cytosine deaminase::uracil phosphoribosyl transferase suicide fusion gene (yCD::UPRT-MSCs) released exosomes in conditional medium (CM). Exosomes from all tissue specific yCD::UPRT-MSCs contained mRNA of the suicide gene in the exosome's cargo. When the CM was applied to tumor cells, the exosomes were internalized by recipient tumor cells and in the presence of the prodrug 5-fluorocytosine (5-FC) effectively triggered dose-dependent tumor cell death by endocytosed exosomes via an intracellular conversion of the prodrug 5-FC to 5-fluorouracil. Exosomes were found to be responsible for the tumor inhibitory activity. The presence of microRNAs in exosomes produced from naive MSCs and from suicide gene transduced MSCs did not differ significantly. MicroRNAs from yCD::UPRT-MSCs were not associated with therapeutic effect. MSC suicide gene exosomes represent a new class of tumor cell targeting drug acting intracellular with curative potential.

• Klíčová slova
• Gene directed enzyme prodrug therapy, MSC suicide gene exosomes, mesenchymal stem cells, suicide gene,
• MeSH
• cytosindeaminasa genetika   metabolismus   MeSH
• exozómy genetika   metabolismus   MeSH
• flucytosin metabolismus   MeSH
• fluoruracil metabolismus   farmakologie   MeSH
• fungální proteiny genetika   metabolismus   MeSH
• genetická terapie metody   MeSH
• kvasinky genetika   metabolismus   MeSH
• lidé MeSH
• mezenchymální kmenové buňky metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádory prsu genetika   metabolismus   patologie   MeSH
• pentosyltransferasy genetika   metabolismus   MeSH
• prekurzory léčiv metabolismus   MeSH
• proliferace buněk účinky léků   genetika   MeSH
• protinádorové antimetabolity metabolismus   farmakologie   MeSH
• transgeny sebevražedné genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytosindeaminasa MeSH
• flucytosin MeSH
• fluoruracil MeSH
• fungální proteiny MeSH
• pentosyltransferasy MeSH
• prekurzory léčiv MeSH
• protinádorové antimetabolity MeSH
• uracil phosphoribosyltransferase MeSH Prohlížeč

A systematic study of the cleavage of DNA sequences containing 5-fluorocytosine or 5-fluorouracil by type II restriction endonucleases (REs) was performed and the results compared with the same sequences containing natural pyrimidine bases, uracil or 5-methylcytosine. The results show that some REs recognize fluorine as a hydrogen on cytosine and cleave the corresponding sequences where the presence of m5dC leads to blocking of the cleavage. However, on uracil, the same REs recognize the F as a methyl surrogate and cleave the sequences which are not cleaved if uracil is incorporated instead of thymine. These results are interesting for understanding the recognition of DNA sequences by REs and for manipulation of the specific DNA cutting.

• Klíčová slova
• DNA, DNA polymerase, Modified nucleotides, Pyrimidine nucleosides, Restriction endonucleases,
• MeSH
• DNA analýza   metabolismus   MeSH
• flucytosin chemie   MeSH
• fluoruracil chemie   MeSH
• restrikční endonukleasy typu II metabolismus   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• štěpení DNA MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• flucytosin MeSH
• fluoruracil MeSH
• restrikční endonukleasy typu II MeSH

Fourteen clinical isolates of Zygomycetes were tested for their in vitro susceptibility to nine antifungal agents. Susceptibility assessment was performed using a microtiter broth dilution method. Synthetic broth with YNB and glucose was used for 5-fluorocytosine and BHI broth for all the other antimycotics. Amphotericin B exhibited the strongest activity against all isolates tested. MIC values of other two polyenes--nystatin and pimaricin--ranged within the susceptibility limits, with a little pronounced higher activity of pimaricin. The isolates of the genus Absidia and Syncephalastrum were well sensitive to all antimycotics with the exception of 5-fluorocytosine and naftifine. A very weak or zero growth inhibitory effect against all members of the genera Mucor and Rhizopus was found in azoles, 5-fluorocytosine and naftifine.

• MeSH
• allylamin analogy a deriváty   farmakologie   MeSH
• antifungální látky farmakologie   MeSH
• azoly farmakologie   MeSH
• flucytosin farmakologie   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• Mucor účinky léků   MeSH
• Mucorales účinky léků   MeSH
• Rhizopus účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• allylamin MeSH
• antifungální látky MeSH
• azoly MeSH
• flucytosin MeSH
• naftifine MeSH Prohlížeč

The authors submitted a detailed characteristic of the properties of 5-fluorocytosine and its applicability in the treatment of mycoses. They emphasize the advantages of pharmacokinetic parameters of this systemic antimycotic preparation and the possibility to combine it with amphotericin B. Based on their own results of laboratory tests they give an account of the spectrum of sensitive and resistant mycotic agents. According to the authors 5-fluorocytosine is not sufficiently appreciated in Czechoslovakia and it deserves more attention.

• MeSH
• antibiotická rezistence MeSH
• flucytosin * škodlivé účinky   farmakokinetika   terapeutické užití   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• flucytosin * MeSH

The photo-induced conidiation of Trichoderma viride is suppressed by ethidium bromide, acriflavin, lomofungin and 8-quinolinol at concentrations which do not inhibit the colony growth of this deuteromycete.

• MeSH
• akridinová oranž farmakologie   MeSH
• akriflavin farmakologie   MeSH
• azaguanin farmakologie   MeSH
• ethidium farmakologie   MeSH
• fenaziny farmakologie   MeSH
• flucytosin farmakologie   MeSH
• fluoruracil farmakologie   MeSH
• hydroxychinoliny farmakologie   MeSH
• mitosporické houby fyziologie   MeSH
• RNA antagonisté a inhibitory   MeSH
• spory hub MeSH
• světlo * MeSH
• Trichoderma růst a vývoj   fyziologie   účinky záření   MeSH
• vidarabin farmakologie   MeSH
• virginiamycin farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• akridinová oranž MeSH
• akriflavin MeSH
• azaguanin MeSH
• ethidium MeSH
• fenaziny MeSH
• flucytosin MeSH
• fluoruracil MeSH
• hydroxychinoliny MeSH
• RNA MeSH
• vidarabin MeSH
• virginiamycin MeSH

• MeSH
• cytosin analogy a deriváty   MeSH
• flucytosin terapeutické užití   MeSH
• imunosupresivní léčba * MeSH
• kandidóza farmakoterapie   imunologie   MeSH
• myši MeSH
• tvorba protilátek MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytosin MeSH
• flucytosin MeSH