Polyethylenimine based magnetic nanoparticles mediated non-viral CRISPR/Cas9 system for genome editing.

Clustered regularly interspaced short palindromic repeats-associated protein (CRISPR/Cas9) system has become a revolutionary tool for gene editing. Since viral delivery systems have significant side effects, and naked DNA delivery is not an option, the nontoxic, non-viral delivery of CRISPR/Cas9 components would significantly improve future therapeutic delivery. In this study, we aim at characterizing nanoparticles to deliver plasmid DNA encoding for the CRISPR-Cas system in eukaryotic cells in vitro. CRISPR/Cas9 complexed polyethylenimine (PEI) magnetic nanoparticles (MNPs) were generated. We used a stable HEK293 cell line expressing the traffic light reporter (TLR-3) system to evaluate efficient homology- directed repair (HDR) and non-homologous end joining (NHEJ) events following transfection with NPs. MNPs have been synthesized by co-precipitation with the average particle size around 20 nm in diameter. The dynamic light scattering and zeta potential measurements showed that NPs exhibited narrow size distribution and sufficient colloidal stability. Genome editing events were as efficient as compared to standard lipofectamine transfection. Our approach tested non-viral delivery of CRISPR/Cas9 and DNA template to perform HDR and NHEJ in the same assay. We demonstrated that PEI-MNPs is a promising delivery system for plasmids encoding CRISPR/Cas9 and template DNA and thus can improve safety and utility of gene editing.

[Problems of work incapacity of ambulatory patients at the Second Stomatological Clinic, Faculty Hospital with Policlinic, Pekarská, Brno]. / K problematice pracovni neschopnosti ambulantnich pacientu II. stomatologické kliniky FNsP v Brne.

The authors analyze the development of work incapacity in ambulatory patients treated in 1979-1987 by sex, age and period of work incapacity. They used graphic illustrations of time series with a regression line which indicates a rising or declining trend of work incapacity. The analysis revealed that the work incapacity has, with the exception of men aged 15-24 years, a rising trend in particular in women. According the authors this can be partly explained by changes and extension of therapeutic activities in ambulatory surgeries. Certain reserves are also in the planning of therapeutic procedures and control activity.

Genetic variations in the matrix metalloproteinase-1 promoter and risk of susceptibility and/or severity of chronic periodontitis in the Czech population.

OBJECTIVES: Matrix metalloproteinase-1 (MMP-1) is a potent enzyme degrading extracellular matrix that was implicated in the pathogenesis of chronic periodontitis. Therefore, the aim of our study was to examine the association between three promoter polymorphisms of the MMP-1 gene and chronic periodontitis susceptibility and/or severity in a Czech population. MATERIALS AND METHODS: A total of 329 Caucasian subjects were enrolled in this study. They were 133 patients with mild to severe chronic periodontitis and 196 unrelated control subjects. MMP-1 promoter polymorphisms (-1607 1G/2G, -519A/G, and -422A/T) were genotyped using standard polymerase chain reaction-restriction fragment length product methods. RESULTS: Genotype analysis of the three single nucleotide polymorphisms across 27 different combinations showed significant association with chronic periodontitis (p<0.05). Analyses of individual polymorphisms showed no differences in distribution of the -519A/G and -422A/T variants between periodontitis and control groups. However, a trend to increased frequency of the -1607 1G allele was observed in patients with chronic periodontitis compared with the controls (p=0.054). When the groups were further stratified by smoking status, the 1G allele was associated with chronic periodontitis among non-smokers but not among smokers (p=0.033). On the contrary, the distribution of genotype frequencies of the MMP-1 -422A/T polymorphism was different between the patient and control smokers with respect to heterozygotes (73.91% versus 50.91%; p=0.017). CONCLUSIONS: Our results demonstrate that the polymorphisms in the MMP-1 promoter may have only a small effect on the etiopathogenesis of chronic periodontitis.

[Diabetes mellitus in ambulatory stomatosurgical practice]. / Diabetes mellitus v ambulantní stomatochirurgické praxi.

The authors evaluated in 58 patients aged 27-65 years the pre- and postextraction bacteremia after a simple extraction at intervals of 5 minutes, 1 hour, 24 and 72 hours. From the group of 58 examined patients 35 suffered from diabetes mellitus--11 type 1, 24 type 2. Before extraction bacteremia was not found in any of the examined patients. Five minutes after extraction bacteremia was recorded in 50% of the diabetic patients, more frequently in type 1 than type 2. Bacteremia was found in 8% of patients with type 1 diabetes even after 24 hours. The authors recommend to assess in addition to the blood sugar level also so-called glycohaemoglobin which they began to assess regularly in diabetic patients.