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Common Chronic Daily Headaches in Pediatrics

Chapter by: Popova, Valentina; Penn, Rachel
in: Pediatric Headache: Evaluation through Treatment for the General Provider by
[S.l.] : Springer International Publishing, 2023
pp. 67-80
ISBN: 9783031139307
CID: 5500732

Evaluation of human macrophage functional state by voltammetric monitoring of nitrite ions

Popova, Valentina; Korotkova, Elena; Barek, Jiri; Stakheyeva, Marina; Fedorov, Anton; Patysheva, Marina; Cheremisina, Olga
The method for assessing the level of nitric oxide (II) (NO) by voltammetric monitoring of nitrite ions was carried out on models M1 and M2 of polarized macrophages induced from monocytes of human peripheral blood with the addition of lipopolysaccharide (LPS) and interleukin-4 (IL-4), respectively. The model of induction of M1 and M2 macrophages was used in the work to achieve the corresponding shifts in the functional status of studied cells. Ethyl nitrite (EtONO) was used as a standard compound of nitrite ions for electrochemical measurements. Electrochemical determination of nitrite ions was performed by anodic linear sweep voltammetry in the first-order derivative mode (ALSV FOD) in Britton-Robinson (BR) buffer with pH 4.02 on carbon ink modified graphite electrode. EtONO calibrations were linear over a concentration range from 2 to 9 μmol L-1 with corresponding regression equation y = 0.768c - 0.048. Limit of detection (LOD) (S/N = 3) was 0.38 μmol L-1. The results of the study showed the fundamental possibility of using voltammetry to assess indirectly the production of nitric oxide by cells in supernatants of the monocytic macrophage lineage. The level of nitric oxide metabolites (nitrite ions) in supernatants was associated with the functional state of macrophages.
PMID: 31993724
ISSN: 1618-2650
CID: 4299072

Clonal dissemination of multilocus sequence type ST15 KPC-2-producing Klebsiella pneumoniae in Bulgaria

Markovska, Rumyana; Stoeva, Temenuga; Schneider, Ines; Boyanova, Lyudmila; Popova, Valentina; Dacheva, Daniela; Kaneva, Radka; Bauernfeind, Adolf; Mitev, Vanyo; Mitov, Ivan
A total of 36 consecutive clinical and two fecal-screening carbapenem-resistant Klebsiella pneumoniae isolates from two Bulgarian university hospitals (Varna and Pleven) were investigated. Susceptibility testing, conjugation experiments, and plasmid replicon typing were carried out. Beta-lactamases were characterized by isoelectric focusing, PCR, and sequencing. Clonal relatedness was investigated by RAPD and multilocus sequence typing (MLST). Most of the isolates demonstrated multidrug resistance profile. Amikacin and tigecycline retained good activity with susceptibility rates of 95 and 87%, respectively. The resistance rate to colistin was 63%. Six RAPD- and MLST-types were identified: the dominating MLST-type was ST15 (27 isolates), followed by ST76 (six isolates), and ST1350 (two isolates). ST101, ST258, and ST151 were detected once. All except one of the K. pneumoniae produced KPC-2, mostly in combination with CTX-M-15, while for one isolate (ST101) the enzymes OXA-48 and CTX-M-14 were found. All KPC-2-producing transconjugants revealed the presence of IncFII plasmid. The OXA-48- and CTX-M-14-producing isolate showed the presence of L/M replicon type. The dissemination of KPC-2-producing K.pneumoniae in Bulgaria is mainly due to the sustained spread of successful ST15 clone and to a lesser extent of ST76 clone. This is the first report of OXA-48 producing ST101 K. pneumoniae in Bulgaria.
PMID: 26303718
ISSN: 1600-0463
CID: 3231252

Molecular epidemiology and antimicrobial susceptibility of Stenotrophomonas maltophilia in a Bulgarian university hospital over a 5-year period (2007-2012) [Letter]

Bojkova, Milena; Markovska, Rumyana; Stoeva, Temenuga; Strateva, Tanya; Ivanova, Dobrinka; Popova, Valentina; Mitov, Ivan
PMID: 26198085
ISSN: 2374-4243
CID: 3231112