[Comparative Sensitivity of the Luminescent Photobacterium phosphoreum, Escherichia coli, and Bacillus subtilis Strains to Toxic Effects of Carbon-Based Nanomaterials and Metal Nanoparticles].

A comparative analysis of the four commercially available and laboratory luminescent sensor strains to the toxic effect of 10 carbon-based nanomatherials (CBNs) and 10 metal nanoparticles (MNPs) was carried out in this study. The bioluminescence inhibition assays with marine Photobacterium phosphoreum and recombinant Escherichia coli strains were varied in minimal toxic concentrations and EC50 values but led to well correlated biotoxicity evaluation for the most active compounds were ranked as Cu > (MgO, CuO) > (fullerenol, graphene oxide). The novel sensor strain Bacillus subtilis EG 168-1 exhibited the highest sensitivity to CBNs and MNPs that increased significantly number of toxic compounds causing the bacterial bioluminescence inhibition effect.

Enhanced expression of iNOS in human endothelial cells during long-term culturing with extracellular DNA fragments.

NO synthesis by endothelial cells plays an important role in normal function of the cardiovascular system. This work was designed to evaluate the role of variations in properties of extracellular DNA in the regulation of NO synthesis. We studied the effect of four DNA samples with various base sequences (50 ng/ml) on functional activity of endothelial cells HUVEC during 24-h culturing. Human DNA fragments with high content of CG repeats increased intracellular content of NO and its metabolites (nitrites and nitrates) and accelerated oxidation of nitrites to nitrates. Changes in the content of NO metabolites after 24-h culturing was shown to depend on the expression of gene for inducible, but not for endothelial NO synthase. Increased expression of inducible NO synthase positively correlated with an increase in the content of mRNA for the adapter protein MyD88, but did not depend on TLR9 gene expression that encodes protein receptor for CG-DNA recognition. The intracellular concentration of MyD88 mRNA did not depend on the content of TLR9 mRNA. The existence of a variety of DNA-binding receptors apart from TLR9 receptor on the surface of endothelial cells was hypothesized. Activation of these receptors by extracellular DNA fragments stimulates expression of the adapter protein MyD88.

Extracellular DNA affects NO content in human endothelial cells.

Fragments of extracellular DNA are permanently released into the blood flow due to cell apoptosis and possible de novo DNA synthesis. To find out whether extracellular DNA can affect the synthesis of nitric oxide (NO), one of key vascular tone regulators, we studied in vitro effects of three artificial DNA probes with different sequences and 10 samples of extracellular DNA (obtained from healthy people and patients with hypertension and atherosclerosis) on NO synthesis in endothelial cell culture (HUVEC). For detection of NO in live cells and culture medium, we used a NO-specific agent CuFL penetrating into the cells and forming a fluorescent product FL-NO upon interaction with NO. Human genome DNA fragments affected the content of NO in endothelial cells; this effect depended on both the base sequence and concentration of DNA fragments. Addition of artificial DNA and extracellular DNA from healthy people into the cell culture in a low concentration (5 ng/ml) increased the detected NO concentration by 4-fold at most. Cytosine-guanine (CG)-rich fragment of the transcribed sequence of ribosomal repeat was the most powerful NO-inductor. The effect of DNA fragments on NO synthesis was comparable with that of low doses of oxidizing agents, H(2)O(2) and 17ß-estradiol. Extracellular DNA samples obtained from patients with hypertension and atherosclerosis decreased NO content in cells and medium by 1.3-28 times compared to the control; the effect correlated with the content of CG-rich sequences.

[The response of human cancer stem cells on low-dose X-ray exposure].

Recently we found that transposition of homologous chromosomes 1q12 loci towards the nuclear centre and activation of the chromosomal nucleolus-forming regions (NFR) are observed in human lymphocytes after exposure to low doses of X-radiation (10 cGy). These cell reactions were studied for human breast cancer stem cell cultures. There are two cell types in cell culture from single donor: with two (type 1) and three (type 2) loci of 1q12. It was shown that an adaptive response induced by X-ray irradiation is developed only in cells of the type 1 but not in type 2 ones after 3 and 10 cGy doses. We observed a considerable death of cell type 2 after low-dose exposure. Activation of the NFR in breast cancer stem cells after irradiation was not found. In this paper we discuss features of studied cancer stem cells lines and their responses to low doses of ionizing radiation.

[Clinical and morphological aspects of shigellosis flexneri in patients with an aggravated premorbid state]. / Kliniko-morfologicheskie osobennosti shigelleza fleksnera u bol'nykh s otiagoshchennym premorbidnym fonom.

The analysis of 10 fatal outcomes in patients with acute shigellosis during the period of 1999-2000 made it possible to find out that most of deceased shigellosis patients belonged to the group inclined to alcohol abuse and having initial alimentary disturbances. In 6 cases of acute shigellosis with fatal outcome the causative agent was S. flexneri 2a, in 2 cases--S. flexneri 3a, in 1--S. flexneri 4b. The main cause of fatal outcomes was accompanying double pneumonia. Lesions of the intestinal tract in deceased shigellosis patients were of destructive character, resulting, in a number of cases, in serous and perforative peritonitis.

[Colitic variant of the gastrointestinal form of salmonellosis]. / Koliticheskii variant gastrointestinal'noi formy sal'monelleza.

Of 3327 hospitalized patients with salmonellosis, a clinical picture of isolated distal colitis was noted in 142 (4.3%). Acute dysentery was diagnosed in them before the results of bacteriological stool examination were ready. In this variant of salmonellosis S. enteritidis and S. haifa were detected twice as more frequently than in the other variants. As compared to dysentery, the colitic variant of salmonellosis was characterized by more marked intoxication syndrome whereas stomach pains were less spasmodic, less frequently localized in the sigmoid colon; important symptoms for differential diagnosis like tenesmus, false rectal tenesmus, pains and spasms of the sigmoid colon were less frequently noted. Therefore this type of salmonellosis should be included in the clinical classification of salmonellosis of adults on the basis of an obvious clinical picture.

[Cellular and humoral immunity factors in salmonellosis and food toxinfections]. / Sostoianie nekotorykh faktoorov kletochnogo i gumoral'nogo immuniteta pri sal'monelleze i pishchevykh toksikoinfektsiiakh.

The present work deals with the state of cell-mediated and humoral immunity in 129 patients with salmonellosis and 185 patients with alimentary toxicoinfections, determined from the data obtained in the leukocyte migration inhibition (LMI) test and the passive hemagglutination (PHA) test with cysteine, at different stages of the disease and depending on the severity of the infectious process. The results of these investigations showed that in adult salmonellosis patients the specific reaction of T- and B-lymphocytes developed as secondary immune response. The results of the LMI test proved to be unrelated to the severity of the infectious process, while antibody formation was found to be most intensive in the acute course of the disease. The investigations also revealed that the activity of reaction in the LMI est did not depend on the presence of humoral antibodies. In the patients with alimentary toxicoinfections changes in the results of the LMI test and the PHA test with cysteine showed the same regularities as in the salmonellosis patients. This permitted the authors to suggest that diseases of Salmonella etiology prevailed in the former group.