In Vitro Cytotoxicity of CdSe/ZnS Quantum Dots and Their Interaction with Biological Systems

Semiconductor nanocrystals (quantum dots, QDs) have a wide range of potential application in multiplexed tissue and cell imaging, and for in vivo molecular diagnostics and therapy. Therefore studying of the toxicity of QDs and their influence on various cellular processes in vitro is necessary to understand their interaction with living systems.; The paper presents the results of studies on the evaluation of CdSe/ZnS QD cytotoxicity, as well as the results of studying their interaction with freshly prepared human monocytes in vitro. Keywords: Quantum dots, semiconductor nanocrystals, cytotoxicity, in vitro models, monocytes

Cytotoxicity of Polyelectrolyte Microcapsules Encoded with Semiconductor Nanocrystals

Polyelectrolyte microcapsules are promising carriers of drugs and diagnostic agents for designing targeted and controlled delivery systems design. The use of quantum dots (QDs) as fluorescent labels in bioimaging is a promising approach to bioimaging tool development. The potential toxicity of QDs makes their applicability as fluorescent labels in vivo questionable. Therefore, the cytotoxicity of polyelectrolyte microcapsules encoded with semiconductor nanocrystals has been investigated. Keywords: Polyelectrolyte microcapsules, semiconductor nanocrystals, cytotoxicity, theranostic agents

Genetic and epigenetic changes in primary metastatic and nonmetastatic colorectal cancer

Colorectal cancer (CRC) develops as multistep process, which involves genetic and epigenetic alterations. K-Ras, p53 and B-Raf mutations and RASSF1A, E-Cadherin and p16INK4A promoter methylation were investigated in 202 CRCs with and without lymph node and/or liver metastasis, to assess whether gene abnormalities are related to a metastogenic phenotype. K-Ras, B-Raf and p53 mutations were detected in 27, 3 and 32% of the cases, with K-Ras mutations significantly associated with metastatic tumour (P=0.019). RASSF1A, E-Cadherin and p16INK4A methylation was documented in 20, 44 and 33% of the cases with p16INK4A significantly associated with metastatic tumours (P=0.001). Overall, out of 202 tumours, 34 (17%) did not show any molecular change, 125 (62%) had one or two and 43 (21%) three or more. Primary but yet metastatic CRCs were prevalent in the latter group (P=0.023) where the most frequent combination was one genetic (K-Ras in particular) and two epigenetic alterations. In conclusion, this analysis provided to detect some molecular differences between primary metastatic and nonmetastatic CRCs, with K-Ras and p16INK4A statistically altered in metastatic tumours; particular gene combinations, such as coincidental K-Ras mutation with two methylated genes are associated to a metastogenic phenotype

The combined effects of the microcirculatory status and cardiopulmonary bypass on platelet count and function during cardiac surgery

ACKGROUND: Cardiac surgery with cardiopulmonary bypass is associated with important changes in the microcirculation, usually attributed to endothelial dysfunction. Another common finding of cardiac surgery is postoperative thrombocytopenia and platelet loss of function. OBJECTIVE: To investigate the association between microvascular flow pattern and postoperative changes in platelet count and function in cardiac surgery patients. METHODS: Twelve adult cardiac surgery patients received microvascular circulation (sidestream darkfield sublingual mucosa analysis) and platelet count and function (multiple electrode aggregometry ADPtest and TRAPtest) assessment before and after cardiopulmonary bypass. RESULTS: After cardiopulmonary bypass, sublingual microcirculation showed a significantly (P = 0.001) decreased microvascular flow index and increased heterogeneity index (P = 0.006). Platelet function significantly decrease after cardiopulmonary bypass both at ADPtest (P = 0.011) and TRAPtest (P = 0.002). Preoperative patterns of poor microvascular perfusion (low perfused vessels density and total vessels density) were significantly associated with lower values of post-cardiopulmonary bypass platelet function (ADPtest, P = 0.009, TRAPtest, P = 0.031) and count (P = 0.048). CONCLUSIONS: A preoperative disturbance of the microcirculation is associated with a greater postoperative platelet dysfunction. Endothelial damage, chemical and mechanical stimuli are the possible link between the two patterns

Bioregulation of amplitude-phase biological activity of Candida albicans by women reproductive tract microsymbionts

In this study, we propose a chronobiological method for examining inter-microbial interactions in bacterial and fungal associations in female reproductive tract. Fungal and bacterial species were isolated in 45 women of reproductive aged 19–35, with regular menstrual cycle, applying no hormonal contraceptives, without previous gynecological surgery, abortions, miscarriages with vaginal eubiosis and dysbiosis in history. Sexually transmitted diseases (HIV infection, syphilis, gonorrhea, trichomoniasis, chlamydiosis) were excluded in all subjects. Proliferation rate, morphogenesis and phospholipase activity were examined within the 48-hour period every 4 hours, in winter time, Moon phase IV. The data obtained were assessed by using Student’s t-test, Wilcoxon test, and least squares method. All subjects were divided into the groups: group 1 — women with vaginal eubiosis, group 2 — women with vaginal dysbiosis. It was shown that in all subjects experimental parameters of C. albicans cultures showed a diurnal dynamics characterized in healthy women by circadian rhythms with a single peak of activity. However, in women with vaginal dysbiosis C. albicans was characterized by significant ultradian (around 12 hours long) rhythms with two peaks of biological activity. Concurrence and consistency in manifested physiological functions related to clinical isolates was coupled to temporal pattern of distributed biological resources in fungi depending on course of infectious process. It was found that in vaginal eubiosis exometabolites released by dominant associated microbiota did not significantly change microbiota-related amplitude-phase parameters. The data obtained evidenced that temporal pattern of parameters related to C. albicans from healthy individuals was stable and independent on bacterial metabolites. In contrast, dominant microsymbiont in vaginal dysbiosis inhibited fungi-related rhythms, which might be important in establishing lactobacillus-associated biotope colonization resistance. Effects of metabolites released by the associated microbiota typical to dysbiosis was revealed by increased mesor, amplitude, preserved biorhythm spectral pattern in examined properties as well as amplitude-phase characteristics indicating at enhanced or sustained C. albicans adaptive potential. Therefore, the amplitude-phase parameter of C. albicans physiological activity served as a marker of opposite (enhanced/weakened) effect of microsymbiont survival described in “microbial dominant-associate” pairs

Combinatorial CRISPR-Cas9 screens for de novo mapping of genetic interactions.

We developed a systematic approach to map human genetic networks by combinatorial CRISPR-Cas9 perturbations coupled to robust analysis of growth kinetics. We targeted all pairs of 73 cancer genes with dual guide RNAs in three cell lines, comprising 141,912 tests of interaction. Numerous therapeutically relevant interactions were identified, and these patterns replicated with combinatorial drugs at 75% precision. From these results, we anticipate that cellular context will be critical to synthetic-lethal therapies

VID22 counteracts G-quadruplex-induced genome instability

Genome instability is a condition characterized by the accumulation of genetic alterations and is a hallmark of cancer cells. To uncover new genes and cellular pathways affecting endogenous DNA damage and genome integrity, we exploited a Synthetic Genetic Array (SGA)-based screen in yeast. Among the positive genes, we identified VID22, reported to be involved in DNA double-strand break repair. vid22Δ cells exhibit increased levels of endogenous DNA damage, chronic DNA damage response activation and accumulate DNA aberrations in sequences displaying high probabilities of forming G-quadruplexes (G4-DNA). If not resolved, these DNA secondary structures can block the progression of both DNA and RNA polymerases and correlate with chromosome fragile sites. Vid22 binds to and protects DNA at G4-containing regions both in vitro and in vivo. Loss of VID22 causes an increase in gross chromosomal rearrangement (GCR) events dependent on G-quadruplex forming sequences. Moreover, the absence of Vid22 causes defects in the correct maintenance of G4-DNA rich elements, such as telomeres and mtDNA, and hypersensitivity to the G4-stabilizing ligand TMPyP4. We thus propose that Vid22 is directly involved in genome integrity maintenance as a novel regulator of G4 metabolism