Pyrazinamide plays an important role in the treatment of tuberculosis. However, the microbiological test for pyrazinamide resistance is more complex and less reliable than testing of susceptibility ...to other anti-tuberculosis drugs due to the need to grow the pathogen at pH 5.5. Identification of mutations that cause resistance to anti-tuberculosis drugs can replace microbiological methods. Mutations in the
pncA
gene are responsible for the main mechanism of the resistance to pyrazinamide and are found in more than 90% of resistant strains. However, the genetic method for determining drug susceptibility is very complex, because mutations leading to pyrazinamide resistance are diverse and scattered throughout the gene. We have developed a software package for automatic data interpretation and prediction of the resistance to pyrazinamide based on Sanger sequencing results. The effectiveness of detection of pyrazinamide resistance in 16 clinical samples was compared using the BACTEC MGIT 960 automated system and
pncA
gene Sanger sequencing with automated analysis of the results. A significant advantage of the developed method over a single microbiological study was shown, due to greater reliability of the results irrespective of the purity of isolates.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The dynamics of lung microbiota in tuberculosis remains poorly understood. Sequencing of variable regions of the 16S rRNA gene from surgically excised tuberculosis foci and biopsy specimens of normal ...lung tissue allowed characterization of the diversity and predictive potential of bacterial communities. Taxonomic diversity indices attested to differences in the structure of microbial communities between “healthy” lungs and tuberculomas. The microbial composition of “healthy” lungs varied in taxonomic diversity and was presented by both gram-positive and gram-negative bacteria with sufficiently similar metabolic potential. The microbiota of the examined tuberculomas consisted of
Mycobacterium tuberculosis
in 99.9% of cases. A significant part of the metabolic pathways predicted by PICRUSt2 included cholesterol catabolism, sulfate assimilation, and various pathways for the biosynthesis of cell wall components.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The effect of the physical and additive-manufacturing (3D printing) characteristics on the structure and hardness of monolith and netlike articles fabricated from the Al–Cu–Mg–Si alloy by selective ...laser melting,—is considered. The structure and hardness of monolith samples, which were synthesized at the laser powers
P
= 100–200 W, scanning speeds
V
= 400–950 mm/s, and unchanged both laser beam spot diameters of 60 and 75 µm and powder layer thickness of 0.05 mm,—were compared and analysed. It has been found that the hardness of samples synthesized at
Р
= 200 W and
V
= 750–900 mm/s is 50HB10/250; the minimum hardness (less than 28HB10/250) is observed for the samples fabricated at
V
= 400 mm/s and
Р
= 100 W. Metallographic studies of the structure of samples exhibit the presence of defects, such as shrinkage voids, hot cracks, and non-melt powder particles. Experimental data indicating the correlation between the build geometry of netlike samples characterized by different filling levels (amount and configuration of the internal construction holes) and their dynamic properties measured by Hopkinson–Kolsky compression tests are obtained. It has been found that the decrease in the density (ρ = 2.44 – 1.19 g/cm
3
) and increase in the total fraction of hole area in the build plane and plane perpendicular to the build plane from 4 to 86% leads to the decrease in the dynamic mechanical properties, namely, the yield stress and ultimate tensile strength by 3 and by 4.7 times, respectively.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Monolith and bulk-structured samples of different densities have been obtained using selective laser melting on a Realizer SLM 100 3D-printer intended for metals. Their quality and structure have ...been estimated via metallography and scanning electron microscopy. The correlation has been established between the parameters of synthesis, namely, between the intertrack distance and layer thickness at a laser power of 200 W, on the one hand, and structural characteristics, on the other. Based on the experimental results, the optimum operating parameters of a 3D-printer were found to obtain the Al–Cu–Mg–Si samples with dispersed structure and high mechanical properties. The features of the synthesis of bulk-structured samples with cubic geometry of plotting have been studied, and the types of defects that affect the quality and mechanical properties of samples have been determined.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
—
A novel monomer for the synthesis of polyimides, 5-methyl-1,3-phenylene-bis-4-oxyphthalic acid dianhydride was developed. The synthesis was carried out in three stages: the reaction of nucleophilic ...nitro substitution of 4-nitrophthalonitrile with 5‑methylresorcinol (orcinol) potassium salt and subsequent hydrolysis of the nitrile groups have afforded 5‑methyl-1,3-phenylene-bis-4-oxyphthalic acid, dehydration of which has given the corresponding dianhydride. A series of new thermoplastic high molecular weight polyetherimides based on 5-methyl-1,3-phenylene-bis-4-oxyphthalic acid dianhydride and several aromatic diamines of various structures were synthesized by the method of one-stage catalytic polycondensation in a benzoic acid melt. Inherent viscosity and weight-average molecular mass of the polyetherimides have been of 0.28‒1.20 dL/g and (33‒114) × 10
3
, respectively. The polyetherimides have been soluble in chloroform, THF, DMF, DMAA,
N
-methylpyrrolidone, and DMSO and have revealed film-forming properties. According to the DSC and wide-angle X-ray scattering data, the polyetherimides have been found completely amorphous, the glass transition temperature being in the 185–307°C range.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Introduction:
Lung cancer is one of the most common cancers in the world. Approximately 40% of all metastases make up brain metastases that occur in 3% of patients at early stages of lung cancer. ...Early diagnosis of brain metastases directly affects patients’ survival and quality of life.
Objective:
To study the role of contrast-enhanced magnetic resonance imaging (MRI) in detecting brain metastases at the outpatient stage in patients with newly diagnosed and histologically confirmed lung cancer and to compare the findings to that of computed tomography (CT).
Materials and methods:
Our study was conducted at the premises of the Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation) between November 2022 and January 2023. Seventyfive patients with histologically confirmed lung cancer underwent brain MRI on a Philips Panorama 1.0T MRI scanner and intravenous administration of Clariscan to detect metastatic lesions. As a diagnostic method, we used a “short” scanning protocol in T1-WI (TR: 450, TE: 15, slice thickness 5 mm), T2-WI (TR: 4533, TE: 100, slice thickness 5 mm) and DWI (TR: 3712, TE: 97, slice thickness 5 mm) modes in the axial plane, then the Clariscan contrast agent was injected intravenously at the rate of 0.2 ml per 1 kg of the patient's weight, after which the scan was repeated using 3D T1 (TR: 450, TE: 15, slice thickness 1 mm).
Results:
The average age of the patients was 60 years. The majority of the participants were male. Of all the patients, the majority had central lung cancer (57.3%). During contrast-enhanced brain MRI, brain metastases that accumulated a contrast agent in 100% of cases were detected in 30 patients (40%) of the total number of patients. In 7% of the patients, there were non-metastatic findings undetected by prior contrast-enhanced CT, such as pontine cavernoma and venous malformations. After MRI for brain metastases, management strategies changed in 30 (40%) patients.
Discussion:
Contrast-enhanced MRI is one of the most effective methods for diagnosing metastatic lesions. It allows to localize brain metastases and helps the clinician choose the most effective management strategy. The introduction of contrast-enhanced brain MRI into routine medical practice could improve the accuracy and quality of brain metastasis detection in patients with lung cancer.
The results of monitoring of undesirable South American weed
Acanthospermum hispidum
DC conducted in Primorsky krai in 2020–2021 are presented. The territories of the first detections of the species ...in the Far East and the sites of its probable accidental introduction connected with imported products, crops, and ruderal communities were examined. Regional and All-Russian floristic checklists published for the last 30 years as well as data on the contamination of crops were analyzed. The study confirmed the status of the species as being absent within the territory of the Russian Federation. However, a high probability of the entry of the pest fruits as a contaminant of imported agricultural products from the countries of wide pest distribution and its successful naturalization in suitable conditions remains.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Background
. Bedaquiline is a new and promising anti-tuberculosis drug, but longterm use requires resistance. This is due to mutations in the atpE and mmpR genes in M. tuberculosis (MBT).
The aim of ...the research
was to test a system for automated interpretation of results for predicting resistance to bedaquiline by the molecular data.
Materials and methods
. DNA was isolated from strains of M. tuberculosis in the Irkutsk region and Yakutia. The total quantity of DNA samples was 27 strains from Yakutia and 21 strains from the Irkutsk region. The study of MBT genomes was carried out on the DNA previously obtained by the authors in the territories of the Irkutsk region (n = 5), Yakutia (n = 4), Buryatia (n = 3), Zabaykalskiy kray (n = 4) and the Far East (n = 8). We used the BSATool program to detect bedaquiline resistance based on Sanger and genomic data. Sanger sequencing analyzed the atpE and mmpR genes, and whole genome sequencing examined mutations in the same sequences, as well as additionally in mmpL5, mmpS5, Rv0678, Rv1979c, and pepQ.
Results
. Complete agreement between the phenotypic and genotypic analysis of resistance to bedaquiline was found for three strains from Yakutia. One genome with significant mutations to bedaquiline was identified. A conclusion was made about the importance of molecular analysis of target genes with subsequent detection of resistance to bedaquiline in silico.
Background
. The study of the lower respiratory tract microbiome has been actively developed inrecent years with the help of whole genome sequencing (WGS) methods. Due to this, it became clear that ...the nature of the lungs microbiota is very different from other microbial communities inhabiting the human body. One of the important directions in the study of pathological lungs biocenosis is the study of the role of the satellite microbiota of the tuberculosis focus.
The aim of the work
. To isolate and characterize oxygen-tolerant anaerobes from the necrotic contents of tuberculomas.
Materials and methods
. Biopsy material from 5 patients with pulmonary tuberculosis was obtained during a planned surgical treatment of tuberculoma. A pure culture was isolated from one sample during anaerobic cultivation. Lipase activity of strain was determined by plating on brain heart infusion agar (HIMEDIA, India) supplemented with 0.1 % Tween-80 and 10 mM of CaCl
2
. Antibiotic susceptibility was determined by RAPMYCO and SLOWMYCO of TREK Diagnostic Systems (Thermo Fisher Scientific, USA). DNA from the sediment of the broth culture was isolated by the CTAB chloroform method. Whole genome sequencing was performed on a DNBSeq-G400 NGS sequencer by Genomed (Russia).
Results
. Based on WGS results and phylogenetic analysis, the strain was identified as Corynebacterium kefirresidentii. The strain was characterized by high lipase activity and resistance only to Isoniazid, Ethionamide and Trimethoprim/Sulfamethoxazolin.
Conclusion
. The isolation of a lipophilic anaerobic representative of the Corynebacterium tuberculostearicum species complex from a tuberculous focus indicates a possible role of the non-tuberculous microbiota in the liquefaction of caseous necrosis. We assumed that in some cases, favorable conditions are created inside the tuberculous focus for the development of satellite anaerobic lipophilic microbiota.
We studied the role of hydrogen peroxide in the response of tumor cells to treatment with ozonated culture medium. Changes of the level of hydrogen peroxide in tumor cells incubated in ozonated ...medium were detected by using fluorescence microscopy and genetically-encoded sensor HyPer2. Modifications of fluorescent properties of the sensor reflecting accumulation of hydrogen peroxide in the cell cytoplasm were detected within 70 min from the start of exposure. The concentration of hydrogen peroxide continued to increase until 375 min. The revealed changes support the involvement of hydrogen peroxide in the cell response to ozone treatment.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
