Preliminary Study on the Effect of a Single High-Energy Electromagnetic Pulse on Morphology and Free Radical Generation in Human Mesenchymal Stem Cells

The effect of nanosecond electromagnetic pulses on human health, and especially on forming free radicals in human cells, is the subject of continuous research and ongoing discussion. This work presents a preliminary study on the effect of a single high-energy electromagnetic pulse on morphology, viability, and free radical generation in human mesenchymal stem cells (hMSC). The cells were exposed to a single electromagnetic pulse with an electric field magnitude of ~1 MV/m and a pulse duration of ~120 ns generated from a 600 kV Marx generator. The cell viability and morphology at 2 h and 24 h after exposure were examined using confocal fluorescent microscopy and scanning electron microscopy (SEM), respectively. The number of free radicals was investigated with electron paramagnetic resonance (EPR). The microscopic observations and EPR measurements showed that the exposure to the high-energy electromagnetic pulse influenced neither the number of free radicals generated nor the morphology of hMSC in vitro compared to control samples.

Nanosecond Pulsed Electric Field Only Transiently Affects the Cellular and Molecular Processes of Leydig Cells

The purpose of this study was to verify whether the nanosecond pulsed electric field, not eliciting thermal effects, permanently changes the molecular processes and gene expression of Leydig TM3 cells. The cells were exposed to a moderate electric field (80 quasi-rectangular shape pulses, 60 ns pulse width, and an electric field of 14 kV/cm). The putative disturbances were recorded over 24 h. After exposure to the nanosecond pulsed electric field, a 19% increase in cell diameter, a loss of microvilli, and a 70% reduction in cell adhesion were observed. Some cells showed the nonapoptotic externalization of phosphatidylserine through the pores in the plasma membrane. The cell proportion in the subG1 phase increased by 8% at the expense of the S and G2/M phases, and the DNA was fragmented in a small proportion of the cells. The membrane mitochondrial potential and superoxide content decreased by 37% and 23%, respectively. Microarray’s transcriptome analysis demonstrated a negative transient effect on the expression of genes involved in oxidative phosphorylation, DNA repair, cell proliferation, and the overexpression of plasma membrane proteins. We conclude that nanosecond pulsed electric field affected the physiology and gene expression of TM3 cells transiently, with a noticeable heterogeneity of cellular responses.

The red-light emitting diode irradiation increases proliferation of human bone marrow mesenchymal stem cells preserving their immunophenotype

PURPOSE

For effective clinical application of human bone marrow mesenchymal stem cells (hBM-MSCs), the enhancement of their proliferation in vitro together with maintaining the expression of their crucial surface antigens and differentiation potential is necessary. The present study aimed to investigate the effect of light-emitting diode (LED) irradiation on hBM-MSCs proliferation after two, five, or nine days post-irradiation.

MATERIALS AND METHODS

The hBM-MSCs were exposed to the LED light at 630 nm, 4 J/cm², and power densities of 7, 17, or 30 mW/cm². To assess the cell proliferation rate in the sham-irradiated and irradiated samples the cells metabolic activity and DNA content were determined. The number of apoptotic and necrotic cells in the samples was also evaluated. The expression of the crucial surface antigens of the hBM-MSCs up to nine days after irradiation at 4 J/cm² and 17 mW/cm² was monitored with flow cytometry. Additionally, the potential of hBM-MSCs for induced differentiation was measured.

RESULTS

When the metabolic activity was assayed, the significant increase in the cell proliferation rate by 31 and 50% after the irradiation with 4 J/cm² and 17 mW/cm², respectively, was observed at day five and nine when compared to the sham-irradiated cells (p < .05). Similarly, DNA content within the irradiated hBM-MSCs increased by 31 and 41% at day five and nine after the irradiation with 4 J/cm² and 17 mW/cm² in comparison to the sham-irradiated cells. LED irradiation did not change the expression of the crucial surface antigens of the hBM-MSCs up to nine days after irradiation at 4 J/cm² and 17 mW/cm². At the same experimental conditions, the hBM-MSCs maintain in vitro their capability for multipotential differentiation into osteoblasts, adipocytes, and chondrocytes.

CONCLUSION

Therefore, LED irradiation at a wavelength of 630 nm, energy density 4 J/cm², and power density 17 mW/cm² can effectively increase the number of viable hBM-MSCs in vitro.

Persistence of non-typeable Haemophilus Influenzae in the pharynx of children with adenotonsillar hypertrophy after treatment with azithromycin

This study was performed in children with adenotonsillar hypertrophy to evaluate the effect of azithromycin (AZT) on the presence of NTHi in monocyte/macrophages (CD14(+) cells) of adenoids/tonsils and the persistence of NTHi after adenotonsillectomy. A total of 36 pediatric patients participated in the study: 20 children were treated with AZT before adenotonsillectomy, and 16 children did not receive the antibiotic prior to surgery. NTHi were identified by culture and PCR in swabs and tissue samples. NTHi was detected in the lysates of CD14(+) cells by fluorescence in situ hybridization (FISH) and by culture. The molecular typing was used to cluster NTHi isolates from each child. The intracellular NTHi was found in 10 (62.5%) untreated patients and was identified in three (15%) azithromycin-treated patients (P = 0.003). The proportion of the persistent NTHi strains was similar in both groups. AZT treatment followed by adenotonsillectomy did not completely eliminate NTHi from pharynges; however, it significantly reduced the risk of carriage of Haemophilus influenzae inside the CD14(+) cells.

Carriage of antibiotic-resistant Haemophilus influenzae strains in children undergoing adenotonsillectomy

Haemophilus influenzae is one of the major pathogenic bacteria in upper respiratory tract of children. In this study, the presence of various H. influenzae genotypes were followed-up for at least 13 weeks, starting from one week before surgery. Forty-one children with chronic adenoid hypertrophy were prospectively enrolled to the study. The consecutive swabs of adenoid and tonsils, two before adenotonsillectomy and two after the surgery together with homogenates of adenotonsillar tissues and lysates of the CD14(+) cells fraction were acquired from 34 children undergoing adenotonsillectomy. Up to ten isolates from each patient at each collection period were genotyped using a PFGE method and their capsular type and antibiotic susceptibility was determined. Of the 1001 isolates examined, we identified 325 isolates grouped into 16 persistent genotypes, which colonized throats for more than seven weeks and were not eliminated by the surgery. The other 506 isolates grouped into 48 transient genotypes that had been eliminated by the surgery. The resistance to ampicillin were found in 23.8% of the transient strains, and 4.7% of the newly acquired strains following the surgical intervention. In contrast, none of the persistent strains were resistant to ampicillin; however, these strains showed apparently higher level of resistance to co-trimoxazole when compared to transient strains. The transient and persistent strains did not significantly differ in bacterial viability in the biofilms formed in vitro. Some of the strains were identified in two or three different patients and were considered as the strains circulating in the region between 2010 and 2012.