Deep ultraviolet 266 nm laser excitation for flow cytometry

High dimensional flow cytometry relies on multiple laser sources to excite the wide variety of fluorochromes now available for immunophenotyping. Ultraviolet lasers (usually solid state 355 nm) are a critical part of this as they excite the BD Horizon™ Brilliant Ultraviolet (BUV) series of polymer fluorochromes. The BUV dyes have increased the number of simultaneous fluorochromes available for practical high-dimensional analysis to greater than 40 for spectral cytometry. Immunologists are now seeking to increase this number, requiring both novel fluorochromes and additional laser wavelengths. A laser in the deep ultraviolet (DUV) range (from ca. 260 to 320 nm) has been proposed as an additional excitation source, driven by the on-going development of additional polymer dyes with DUV excitation. DUV lasers emitting at 280 and 320 nm have been previously validated for flow cytometry but have encountered practical difficulties both in probe excitation behavior and in availability. In this article, we validate an even shorter DUV 266 nm laser source for flow cytometry. This DUV laser provided minimal excitation of the BUV dyes (a desirable characteristic for high-dimensional analysis) while demonstrating excellent excitation of quantum nanoparticles (Qdots) serving as surrogate fluorochromes for as yet undeveloped DUV excited dyes. DUV 266 nm excitation may therefore be a viable candidate for expanding high-dimensional flow cytometry into the DUV range and providing an additional incidental excitation wavelength for spectral cytometry. Excitation in a spectral region with strong absorption by nucleic acids and proteins (260-280 nm) did result in strong autofluorescence requiring care in fluorochrome selection. DUV excitation of endogenous molecules may nevertheless have additional utility for label-free analysis applications.

Evaluation of Cryopreserved Ram Sperm with Nano-Ozone Solution and Post-Thaw Life Span by Flow Cytometric Analysis

Ozone has been used as a therapy tool in medical science for conditions such as ulcers, peritonitis, wounds, and mostly joint problems. Ozone therapy strengthens the resistance to infections by kick-starting antioxidant, anti-inflammatory, and immune modulation systems. Ozone creates a defensive response against oxidative stress in membranes and protects metabolism against reactive oxygen species (ROS). Sperm membranes are one of ROS's main targets; therefore, the cells' cryopreservation process requires more defensive elements for better results. This study aimed to investigate the protective effect of nano-ozone solution (NOS) on ram sperm cryopreservation and the influence of the process on various sperm parameters for post-thaw (0 hour) and postincubation (6 hours) time points. Samples were collected from six Merino rams in the breeding season by electroejaculation five times at 3-day intervals. The study was conducted by cryopreservation of the samples using a tris citric acid-egg yolk-based extender. The samples were subjected to freezing in control and NOS (0.5, 1, and 2 μg/mL nano-ozone supplemented). Post-thaw motility, hypo-osmotic swelling test, acrosome (fluorescein isothiocyanate-conjugated Pisum sativum agglutinin [PSA-FITC]), and DNA integrities (terminal deoxynucleotidyl transferase dUTP nick end labeling [TUNEL]) were evaluated with a phase-contrast microscope. Mitochondrial membrane potential (MMP) assessments were conducted by JC1-PI dual staining with a flow cytometer. Malondialdehyde and glutathione (GSH) levels were measured by a spectrophotometer. Sperm kinematics were investigated by a computer-assisted sperm analyzer (CASA) at the post-thaw time point. Compared with the control, relatively low doses of NOS (0.5 and 1 μg/mL) yielded better results in many parameters (motility, membrane and acrosomal integrities, MMP, various sperm kinematics, and GSH levels) (p < 0.05). The addition of low ozone doses to cryopreservation extenders improved the results compared with the control group at post-thaw and postincubation time points. Despite the valuable potential of nano-ozone supplementation in ram sperm cryopreservation, this subject requires further investigations with fertility trials soon.

Salinity-Induced Physiochemical Alterations to Enhance Lipid Content in Oleaginous Microalgae Scenedesmus sp. BHU1 via Two-Stage Cultivation for Biodiesel Feedstock

In the recent past, various microalgae have been considered a renewable energy source for biofuel production, and their amount and extent can be enhanced by applying certain types of stress including salinity. Although microalgae growing under salinity stress result in a higher lipid content, they simultaneously reduce in growth and biomass output. To resolve this issue, the physiochemical changes in microalgae Scenedesmus sp. BHU1 have been assessed through two-stage cultivation. In stage-I, the maximum carbohydrate and lipid contents (39.55 and 34.10%) were found at a 0.4 M NaCl concentration, while in stage-II, the maximum carbohydrate and lipid contents (42.16 and 38.10%) were obtained in the 8-day-old culture. However, under increased salinity, Scenedesmus sp. BHU1 exhibited a decrease in photosynthetic attributes, including Chl-a, Chl-b, Fv/Fm, Y(II), Y(NPQ), NPQ, qP, qL, qN, and ETRmax but increased Y(NO) and carotenoids content. Apart from physiological attributes, osmoprotectants, stress biomarkers, and nonenzymatic antioxidants were also studied to elucidate the role of reactive oxygen species (ROS) facilitated lipid synthesis. Furthermore, elemental and mineral ion analysis of microalgal biomass was performed to evaluate the biomass quality for biofuel and cell homeostasis. Based on fluorometry analysis, we found the maximum neutral lipids in the 8-day-old grown culture at stage-II in Scenedesmus sp. BHU1. Furthermore, the use of Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the presence of higher levels of hydrocarbons and triacylglycerides (TAGs) composed of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in the 8-day-old culture. Therefore, Scenedesmus sp. BHU1 can be a promising microalga for potential biodiesel feedstock.

Prism Design for Spectral Flow Cytometry

Flow cytometers are instruments used for the rapid quantitative analysis of cell suspension. Traditional flow cytometry uses multi-channel filters to detect fluorescence, whereas full-spectrum fluorescence based on dispersion detection is a more effective and accurate method. The application of various dispersion schemes in flow cytometry spectroscopy has been studied. From the perspective of modern detectors and demand for the miniaturization of flow cytometry, prism dispersion exhibits higher and more uniform light energy utilization, meaning that it is a more suitable dispersion method for small flow cytometers, such as microfluidic flow cytometers. Prism dispersion designs include the size, number, and placement of prisms. By deducing the formula of the final position of light passing through the prism and combining it with the formula of transmittance, the design criteria of the top angle and the incident angle of the prism in pursuit of the optimum transmittance and dispersion index can be obtained. Considering the case of multiple prisms, under the premise of pursuing a smaller size, the optimal design criteria for dispersion system composed of multiple prisms can be obtained. The design of prism dispersion fluorescence detection was demonstrated with a microfluidic flow cytometer, and the effectiveness of the design results was verified by microsphere experiments and practical biological experiments. This design criterion developed in this study is generally applicable to spectral flow cytometers.

Autofluorescence-based high-throughput isolation of nonbleaching Cyanidioschyzon merolae strains under nitrogen-depletion

Photosynthetic organisms maintain optimum levels of photosynthetic pigments in response to environmental changes to adapt to the conditions. The identification of cyanobacteria strains that alleviate bleaching has revealed genes that regulate levels of phycobilisome, the main light-harvesting complex. In contrast, the mechanisms of pigment degradation in algae remain unclear, as no nonbleaching strains have previously been isolated. To address this issue, this study attempted to isolate nonbleaching strains of the unicellular red alga Cyanidioschyzon merolae after exposure to nitrogen (N)-depletion based on autofluorescence information. After four weeks under N-depletion, 13 cells from 500,000 cells with almost identical pre- and post-depletion chlorophyll a (Chl a) and/or phycocyanin autofluorescence intensities were identified. These nonbleaching candidate strains were sorted via a cell sorter, isolated on solid medium, and their post-N-depletion Chl a and phycocyanin levels were analyzed. Chl a levels of these nonbleaching candidate strains were lower at 1-4 weeks of N-depletion similar to the control strains, however, their phycocyanin levels were unchanged. Thus, we successfully isolated nonbleaching C. merolae strains in which phycocyanin was not degraded under N-depletion, via autofluorescence spectroscopy and cell sorting. This versatile method will help to elucidate the mechanisms regulating pigments in microalgae.

Synergetic Effect of Tumor Treating Fields and Zinc Oxide Nanoparticles on Cell Apoptosis and Genotoxicity of Three Different Human Cancer Cell Lines

Cancer remains a leading cause of death worldwide, despite extraordinary progress. So, new cancer treatment modalities are needed. Tumor-treating fields (TTFs) use low-intensity, intermediate-frequency alternating electric fields with reported cancer anti-mitotic properties. Moreover, nanomedicine is a promising therapy option for cancer. Numerous cancer types have been treated with nanoparticles, but zinc oxide nanoparticles (ZnO NPs) exhibit biocompatibility. Here, we investigate the activity of TTFs, a sub-lethal dose of ZnO NPs, and their combination on hepatocellular carcinoma (HepG2), the colorectal cancer cell line (HT-29), and breast cancer cell lines (MCF-7). The lethal effect of different ZnO NPs concentrations was assessed by sulforhodamine B sodium salt assay (SRB). The cell death percent was determined by flow cytometer, the genotoxicity was evaluated by comet assay, and the total antioxidant capacity was chemically measured. Our results show that TTFs alone cause cell death of 14, 8, and 17% of HepG2, HT-29, and MCF-7, respectively; 10 µg/mL ZnO NPs was the sub-lethal dose according to SRB results. The combination between TTFs and sub-lethal ZnO NPs increased the cell death to 29, 20, and 33% for HepG2, HT-29, and MCF-7, respectively, without reactive oxygen species increase. Increasing NPs potency using TTFs can be a novel technique in many biomedical applications.

Antiapoptotic and antioxidative efficacy of rhizomes of Curcuma amada on the management of diabetes-induced male infertility in albino rat: An effective fraction selection study

Men with diabetes have negative effects on reproduction that causes sexual dysfunction. Medicinal plants are non-toxic and much safer than synthetic drugs because regular use of synthetic drugs shows long-term side effects. Curcuma amada (Roxb) is a medicinal plant used in Ayurveda and Unani medicinal systems in India. The goal of this study is to rummage the potential efficiency of the most potent solvent fraction of effective extract of hydro-methanol 60:40 of C. amada rhizome on male gonadal hypofunction in streptozotocin-induced diabetic rat. Diabetes-induced testicular hypofunction was evaluated by glycemic, spermiological, biochemical, genomic, flow cytometric, and histology of testicular tissue. The n-hexane, chloroform, ethyl-acetate, and n-butanol solvent fractions of the said extract were administrated for 4 weeks at 10 mg dose/100 g body weight/day. Among all the used fractions, the ethyl-acetate solvent fraction-treated group showed maximum recovery in serum insulin (177.42%), sperm count (92.84%), sperm motility (97.15%), and serum testosterone (164.33%). The diabetic rats treated with ethyl-acetate solvent fraction also exhibited the maximum resettlement in flow cytometric analysis of sperm viability (55.84%) and sperm mitochondrial integrity (149.79%), gene expression patterns of key markers for androgenesis (Δ5, 3β-HSD 87.50%, and 17β-HSD 74.66%) and apoptosis (Bax 44.63%, Bcl-2 54.03%, and Caspase-3 35.77%) along with testicular histology. The ethyl-acetate fraction contains alkaloids, flavonoids, and polyphenols where all of these components are not present in other fractions, may be the most effective cause for the recovery of diabetes-linked oxidative stress-mediated testicular hypofunctions. PRACTICAL APPLICATIONS: Nowadays worldwide, the use of synthetic drugs are reduced due to their toxic effect. At present, synthetic drugs are replaced by several herbal drugs, the natural source of medicine which has many therapeutic values. C. amada has strong antioxidant activity due to the presence of bio-active compound(s) that can able to manage streptozotocin-induced diabetes linked to oxidative damage of male gonadal organs. Therefore, these bio-active compound(s)-containing said medicinal plant may use as a good source of antioxidative food in the food industry as nutraceuticals and in pharmaceutical industries for the development of the herbal drug to manage diabetes-linked male gonadal hypofunctions. At present, WHO also gives emphasis for developing one drug-multi-disease therapy. From such a viewpoint, this active fraction-containing phytomolecules may have corrective efficacy against diabetes as well as oxidative stress-linked testicular complications.

Evaluation and validation of a novel 10-color flow cytometer

Background

Flow cytometry is a powerful technique that provides information regarding cell properties. In this study, we evaluated the analytical performance of a new flow cytometer, the 10‐color BD FACSLyric^TM, which could help doctors obtain reliable test results prior to clinical research.

Methods

We used Sphero^TM Rainbow Calibration Particles and the Sphero^TM Nano Fluorescent Particle Size Standard Kit to validate the fluorescence sensitivity and linearity. The Beckman Coulter IMMUNO‐TROL Cell was used as the quality control to evaluate the accuracy and reproducibility of surface markers detected by the flow cytometer. Furthermore, BD Calibrate APC Beads and CS&T Research Beads were applied to calculate the carry‐over contamination rate and assess the instrument stability.

Results

A linear regression equation between the molecules of equivalent soluble fluorochrome and fluorescence detection limit showed a good linear fit (R² > 0.99). The minimum bead size detected by side scatter was 0.22 μm. The coefficient of variation percentage of each fluorescence channel was below 2%, and the carry‐over contamination rate of the cytometer was under 0.2%. After running the BD FACSLyric^TM cytometer continuously for 8 h, the median fluorescence index of particles remained close to that at the time of cytometer startup.

Conclusions

The 10‐color BD FACSLyric^TM cytometer showed good performance in the evaluation performed in this study and may be trusted to provide accurate results for clinical research.

Optical Biosensor Platforms Display Varying Sensitivity for the Direct Detection of Influenza RNA

Detection methods that do not require nucleic acid amplification are advantageous for viral diagnostics due to their rapid results. These platforms could provide information for both accurate diagnoses and pandemic surveillance. Influenza virus is prone to pandemic-inducing genetic mutations, so there is a need to apply these detection platforms to influenza diagnostics. Here, we analyzed the Fast Evaluation of Viral Emerging Risks (FEVER) pipeline on ultrasensitive detection platforms, including a waveguide-based optical biosensor and a flow cytometry bead-based assay. The pipeline was also evaluated in silico for sequence coverage in comparison to the U.S. Centers for Disease Control and Prevention's (CDC) influenza A and B diagnostic assays. The influenza FEVER probe design had a higher tolerance for mismatched bases than the CDC's probes, and the FEVER probes altogether had a higher detection rate for influenza isolate sequences from GenBank. When formatted for use as molecular beacons, the FEVER probes detected influenza RNA as low as 50 nM on the waveguide-based optical biosensor and 1 nM on the flow cytometer. In addition to molecular beacons, which have an inherently high background signal we also developed an exonuclease selection method that could detect 500 pM of RNA. The combination of high-coverage probes developed using the FEVER pipeline coupled with ultrasensitive optical biosensors is a promising approach for future influenza diagnostic and biosurveillance applications.

Alterations in Mycelial Morphology and Flow Cytometry Assessment of Membrane Integrity of Ganoderma boninense Stressed by Phenolic Compounds

Global increase in demand for palm oil has caused an intensification in oil palm plantation; however, production is greatly hindered by Basal Stem Rot (BSR) disease caused by Ganoderma boninense. There are many approaches to controlling BSR, although, there is no accurate, sustainable and effective method to suppress G. boninense completely. Hence, four phenolic compounds [Gallic acid (GA), Thymol (THY), Propolis (PRO) and Carvacrol (CARV)] were selected to evaluate their antifungal effect, ability to alter the mycelium morphology, and fungal cell integrity against G. boninense. Significant differences (p < 0.05) were observed and 94% of inhibition was exerted by GA on G. boninense growth. Scanning Electron Microscopy and High-Resolution Transmission Electron Microscopy observations revealed that GA and THY treatment caused severe damage to the mycelium and recorded the highest amount of sugar and electrolyte leakage. The study of cell integrity and morphological disruption has elucidated the reduction of G. boninense cell viability. Generally, our findings confirm the fungistatic effects of GA and THY. The evolution of phenolic compounds during the phytopathology studies indicated their coherence in eradicating the G. boninense. It is proposed that GA and THY had the potential to be developed further as a natural antifungal treatment to suppress G. boninense.

Current Applications of Absolute Bacterial Quantification in Microbiome Studies and Decision-Making Regarding Different Biological Questions

High throughput sequencing has emerged as one of the most important techniques for characterizing microbial dynamics and revealing bacteria and host interactions. However, data interpretation using this technique is mainly based on relative abundance and ignores total bacteria load. In certain cases, absolute abundance is more important than compositional relative data, and interpretation of microbiota data based solely on relative abundance can be misleading. The available approaches for absolute quantification are highly diverse and challenging, especially for quantification in differing biological situations, such as distinguishing between live and dead cells, quantification of specific taxa, enumeration of low biomass samples, large sample size feasibility, and the detection of various other cellular features. In this review, we first illustrate the importance of integrating absolute abundance into microbiome data interpretation. Second, we briefly discuss the most widely used cell-based and molecular-based bacterial load quantification methods, including fluorescence spectroscopy, flow cytometry, 16S qPCR, 16S qRT-PCR, ddPCR, and reference spike-in. Last, we present a specific decision-making scheme for absolute quantification methods based on different biological questions and some of the latest quantitative methods and procedure modifications.

Sources of Variability in the Response of Labeled Microspheres and B Cells during the Analysis by a Flow Cytometer

A stochastic model of the flow cytometer measurement process was developed to assess the nature of the observed coefficient of variation (CV%) of the mean fluorescence intensity (MFI) from a population of labeled microspheres (beads). Several sources of variability were considered: the total number of labels on a bead, the path through the laser beam, the optical absorption cross-section, the quantum yield, the numerical aperture of the collection optics, and the photoelectron conversion efficiency of the photomultiplier (PMT) cathode. The variation in the number of labels on a bead had the largest effect on the CV% of the MFI of the bead population. The variation in the path of the bead through the laser beam was minimized using flat-top lasers. The variability in the average optical properties of the labels was of minor importance for beads with sufficiently large number of labels. The application of the bead results to the measured CV% of labeled B cells indicated that the measured CV% was a reliable measure of the variability of antibodies bound per cell. With some modifications, the model can be extended to multicolor flow cytometers and to the study of CV% from cells with low fluorescence signal.

Derivatives of Deoxypodophyllotoxin Induce Apoptosis through Bcl-2/Bax Proteins Expression

BACKGROUND

Deoxypodophyllotoxin, isolated from the Traditional Chinese Medicine Anthriscus sylvestris, is well-known because of its significant anti-tumor activity with strong toxicity in vitro and in vivo.

OBJECTIVE

In this article, a series of deoxypodophyllotoxin derivatives were synthesized and their anti-tumor effectiveness was evaluated.

METHODS

The anti-tumor activity of deoxypodophyllotoxin derivatives was investigated by the MTT assay method. Apoptosis percentage was measured by flow cytometer analysis using Annexin-V-FITC.

RESULTS

The derivatives revealed obvious cytotoxicity in the MTT assay by decreasing the number of late cancer cells. The decrease of Bcl-2/Bax could be observed in MCF-7, HepG2, HT-29, and MG-63 using Annexin V-FITC. The ratio of Bcl-2/Bax in the administration group was decreased, which was determined by the ELISA kit.

CONCLUSION

The derivatives of deoxypodophyllotoxin could induce apoptosis in tumor cell lines by influencing Bcl-2/Bax.

Flow cytometry: principles, applications and recent advances

Flow cytometry (FCM) is a sophisticated technique that works on the principle of light scattering and fluorescence emission by the specific fluorescent probe-labeled cells as they pass through a laser beam. It offers several unique advantages as it allows fast, relatively quantitative, multiparametric analysis of cell populations at the single cell level. In addition, it also enables physical sorting of the cells to separate the subpopulations based on different parameters. In this constantly evolving field, innovative technologies such as imaging FCM, mass cytometry and Raman FCM are being developed in order to address limitations of traditional FCM. This review explains the general principles, main applications and recent advances in the field of FCM.

One-Dimensional Flow of Bacteria on an Electrode Rail by Dielectrophoresis: Toward Single-Cell-Based Analysis

Many applications in biotechnology and medicine, among other disciplines, require the rapid enumeration of bacteria, preferably using miniaturized portable devices. Microfluidic technology is expected to solve this miniaturization issue. In the enumeration of bacteria in microfluidic devices, the technique of aligning bacteria in a single line prior to counting is the key to an accurate count at single-bacterium resolution. Here, we describe the numerical and experimental evaluation of a device utilizing a dielectrophoretic force to array bacteria in a single line, allowing their facile numeration. The device comprises a channel to flow bacteria, two counter electrodes, and a capture electrode several microns or less in width for arranging bacteria in a single line. When the capture electrode is narrower than the diameter of a bacterium, the entrapment efficiency of the one-dimensional array is 80% or more within 2 s. Furthermore, since some cell-sorting applications require bacteria to move against the liquid flow, we demonstrated that bacteria can move in a single line in the off-axial direction tilted 30° from the flow direction. Our findings provide the basis for designing miniature, portable devices for evaluating bacteria with single-cell accuracy.

Single Step In Situ Detection of Surface Protein and MicroRNA in Clustered Extracellular Vesicles Using Flow Cytometry

Because cancers are heterogeneous, it is evident that multiplexed detection is required to achieve disease diagnosis with high accuracy and specificity. Extracellular vesicles (EVs) have been a subject of great interest as sources of novel biomarkers for cancer liquid biopsy. However, EVs are nano-sized particles that are difficult to handle; thus, it is necessary to develop a method that enables efficient and straightforward EV biomarker detection. In the present study, we developed a method for single step in situ detection of EV surface proteins and inner miRNAs simultaneously using a flow cytometer. CD63 antibody and molecular beacon-21 were investigated for multiplexed biomarker detection in normal and cancer EVs. A phospholipid-polymer-phospholipid conjugate was introduced to induce clustering of the EVs analyzed using nanoparticle tracking analysis, which enhanced the detection signals. As a result, the method could detect and distinguish cancer cell-derived EVs using a flow cytometer. Thus, single step in situ detection of multiple EV biomarkers using a flow cytometer can be applied as a simple, labor- and time-saving, non-invasive liquid biopsy for the diagnosis of various diseases, including cancer.

The Scattering of Gold Nanorods Combined with Differential Uptake, Paving a New Detection Method for Macrophage Subtypes Using Flow Cytometery

The strategy of identification for M1 and M2 macrophages both in vivo and in vitro would help to predict the health condition of the individual. Here, we introduced a solution to this problem with the advantage of both the phagocytic nature of macrophages and the scattering effect of gold nanorods (GNRs). The internalized GNRs, relating to their extent of intake, caused a conspicuous scattering profile at the red channel in flow cytometry, overruling the contribution of the cellular side scatters. This internalization is solely governed by the surface chemistry of GNRs. The PAH-GNRs showed maximum intake potency followed by Cit-, PSS-, and PEG-GNRs. On a substantial note, PAH-GNRs lead to differential uptake between M1 and M2 cells, with three times higher intake in M2 cells over M1. This is the first report of employing the scattering of unlabeled GNRs to discriminate M1 and M2 cell types using a flow cytometer.

Stochastic Reaction-Diffusion Model of the Binding of Monoclonal Antibodies to CD4 Receptors on the Surface of T Cells

A stochastic reaction-diffusion model was developed to describe the binding of labeled monoclonal antibodies (mAbs) to CD4 receptors on the surface of T cells. The mAbs diffused to, adsorbed on, and underwent monovalent and bivalent binding to CD4 receptors on the cell surface. The model predicted the time-dependent nature of all populations involved in the labeling process. At large time, the populations reached equilibrium values, giving the number of antibodies bound to the T cell (ABC) defined as the sum of monovalently and bivalently bound mAbs. The predicted coefficient of variation (CV%) of the (ABC) values translated directly to a corresponding CV% of the measured mean fluorescence intensity (MFI). The predicted CV% was about 0.2% from the intrinsic fluctuations of the stochastic reaction process, about 5% after inclusion of the known fluctuations in the number of available CD4 receptors, and about 11% when fluctuations in bivalent binding affinity were included. The fluorescence detection process is expected to contribute approximately 7%. The abovementioned contributions to CV% sum up to approximately 13%. Work is underway to reconcile the predicted values and the measured values of 17% to 22%.

Critical evaluation of two models of flow cytometers for the assessment of sperm DNA fragmentation: an appeal for performance verification

Lack of standardized, reproducible protocols and reference values is among the challenges faced when using new or upgraded versions of instruments in reproductive laboratories and flow cytometry. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay combined with flow cytometry routinely used for diagnostic measurement of sperm DNA fragmentation (SDF) is a unique example. Any change in the setting of the standard instrument, including upgrades of hardware or software, can lead to different results and may affect clinicians’ decision for treatment. Therefore, we compared TUNEL results of SDF obtained from a standard (C6) flow cytometer with a newer version of the same instrument (C6 Plus) and examined the cutoff, sensitivity, and specificity without calibration (adjustment) and after adjustment. Identical sperm preparation and matched acquisition settings were used to examine the performance of two flow cytometers. The strength of agreement of the results between the two observers was also assessed. After adjustment of the settings, overall concordance became high and the two cytometers showed 100% positive and negative predictive value with 100% area under the curve. The overall correlation coefficient observed between C6 and C6 Plus was highly significant (P < 0.0001; r = 0.992; 95% confidence interval [CI]: 0.982–0.997). After adjustment, the two cytometers showed very high precision of 98% and accuracy of >99%. The interobserver agreement on C6 flow cytometer for the two observers was 0.801 ± 0.062 and 0.746 ± 0.044 for C6 Plus. We demonstrated a strong agreement between the samples tested on the two flow cytometers after calibration and established the robustness of both instruments.

TUNEL assay-Standardized method for testing sperm DNA fragmentation

Sperm DNA integrity is important for normal functions such as fertilization, implantation, pregnancy and fetal development. Sperm DNA fragmentation (SDF) is more common in infertile men and may be responsible for poor reproductive function. Although there are a number of tests available to measure SDF, the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labelling TUNEL) assay using flow cytometry is becoming more popular to measure the sperm DNA fragmentation. It is a direct test that measures both single- and double- DNA strand breaks. In this review, we describe the protocol, quality control and measurement of sperm DNA fragmentation using a benchtop flow cytometer. We also briefly discuss the factors that can affect the results, challenges and clinical implications of TUNEL in assessing male infertility.

Antitumor activity associated with hyperthermia and 4-nitrochalcone loaded in superparamagnetic poly(thioether-ester) nanoparticles

The combination of hyperthermia and chemotherapy has a potential synergic effect in antitumor activity. The development of new biocompatible and biodegradable polymers to simultaneously encapsulate magnetic nanoparticles (MNPs) and antitumoral drugs offer new cancer treatment opportunities. Here, biodegradable and biocompatible poly(thioether-ester) (PTEe) was used to encapsulate MNPs and 4-nitrochalcone (4NC) using miniemulsification and solvent evaporation. The resulting hybrid particles (MNPs-4NC-PTEe) had nanometer-scale diameters, spherical morphology, negative surface charge, high encapsulation efficiency, and superparamagnetic properties. Results showed that 4NC release occurred through diffusion. Free 4NC and MNPs + 4NC-PTEe did not have any cytotoxic effect on erythrocytes and mouse embryonic fibroblast (NIH3T3) cells. 4NC antitumor activity was verified on human cervical cancer (HeLa) and melanoma (B16F10) cells. Cellular uptake of MNPs + 4NC-PTEe nanoparticles was higher in HeLa cells compared to B16F10 and NIH3T3 cells. The hyperthermia application (115 kHz-500 Oe) potentiated the 4NC effects on HeLa and B16F10 cells when MNPs + 4NC-PTEe nanoparticles were used, indicating more effective antitumor activity. We concluded that the use of MNPs + 4NC-PTEe nanoparticles associated with hyperthermia is a promising form of treatment for some types of cancers.

Same-day antimicrobial susceptibility test using acoustic-enhanced flow cytometry visualized with supervised machine learning

Purpose. Antimicrobial susceptibility is slow to determine, taking several days to fully impact treatment. This proof-of-concept study assessed the feasibility of using machine-learning techniques for analysis of data produced by the flow cytometer-assisted antimicrobial susceptibility test (FAST) method we developed.Methods. We used machine learning to assess the effect of antimicrobial agents on bacteria, comparing FAST results with broth microdilution (BMD) antimicrobial susceptibility tests (ASTs). We used Escherichia coli (1), Klebsiella pneumoniae (1) and Staphylococcus aureus (2) strains to develop the machine-learning algorithm, an expanded panel including these plus E. coli (2), K. pneumoniae (3), Proteus mirabilis (1), Pseudomonas aeruginosa (1), S. aureus (2) and Enterococcus faecalis (1), tested against FAST and BMD (Sensititre, Oxoid), then two representative isolates directly from blood cultures.Results. Our data machines defined an antibiotic-unexposed population (AUP) of bacteria, classified the FAST result by antimicrobial concentration range, and determined a concentration-dependent antimicrobial effect (CDE) to establish a predicted inhibitory concentration (PIC). Reference strains of E. coli, K. pneumoniae and S. aureus tested with different antimicrobial agents demonstrated concordance between BMD results and machine-learning analysis (CA, categoric agreement of 91 %; EA, essential agreement of 100 %). CA was achieved in 35 (83 %) and EA in 28 (67 %) by machine learning on first pass in a challenge panel of 27 Gram-negative and 15 Gram-positive ASTs. Same-day AST results were obtained from clinical E. coli (1) and S. aureus (1) isolates.Conclusions. The combination of machine learning with the FAST method generated same-day AST results and has the potential to aid early antimicrobial treatment decisions, stewardship and detection of resistance.

Separation of mononuclear cells and identification of B lymphocytes: A comprehensive experiment for medical students

In teaching of experiments for medical students, by using the isolation of mononuclear cells and identification of B lymphocytes, an experiment was developed that integrated biochemistry, cytology, and immunology techniques, from which the students performed a series of operations including spleen separation, isolating mononuclear cells, and identifying B lymphocytes. From the immunocytochemistry detection, we included advanced equipment-a flow cytometer-in the experiment, which detected the B lymphocytes more accurately. Moreover, we applied modern information technology to the teaching of experiments by using an internet study platform, micro-lectures, and adopting "formative teaching and evaluation." This lab practice aims to increase the ability of medical students to solve problems using flexible scientific methods, to initiate them thinking about clinical and research application.

UF-5000 flow cytometer: A new technology to support microbiologists' interpretation of suspected urinary tract infections

This case study aims to describe the adoption of an innovative flow cytometer (i.e., UF-5000), which can support the microbiologists' process of diagnosing suspected urinary tract infections (UTIs). The new clinical information provided can be used to improve the identification of both contamination and colonization, thus reducing inappropriate antibiotic prescriptions. In July and August 2017, the Microbiology Laboratory of Alessandria (Italy) conducted a retrospective monocentric study analyzing data about 1,295 urine specimens from inpatients and outpatients with symptoms of UTIs. The results of this study show that the innovative technology can successfully support the diagnostic process in microbiology laboratories and, consequently, the supply of sustainable treatments by hospitals.

Eriodictyol exerts potent anticancer activity against A549 human lung cancer cell line by inducing mitochondrial-mediated apoptosis, G2/M cell cycle arrest and inhibition of m-TOR/PI3K/Akt signalling pathway

INTRODUCTION

Eriodictyol is an important flavonoid and is commonly present across the plant kingdom. Flavonoids have been reported to show incredible pharmacological potential. However, the anticancer activity of the important flavonoid eriodictyol has not been well reported. In the present study we determined its anticancer potential against the human lung cancer cell line A549.

MATERIAL AND METHODS

The initial cytotoxicity induced by eriodictyol was measured by MTT assay. Flow cytometry was used to study the effects of eriodictyol on apoptosis, cell cycle phase distribution and mitochondrial membrane potential loss. The comet assay was used to measure DNA damage induced by eriodictyol in cancer cells while the western blot assay indicated effects of the compound on Bax/Blc-2 and PI3K/AKT/m-TOR proteins.

RESULTS

The results showed that eriodictyol has an IC₅₀ value of 50 μM against human lung cancer cells as compared to the IC₅₀ of 95 µM against non-cancerous FR2 cells. The molecule exerted its anticancer activity through induction of apoptosis by regulating the Bcl-2/Bax signalling pathway. It caused cell cycle arrest of human lung cancer A549 cells at G2/M phase. Eriodictyol was also found to cause a reduction of the mitochondrial membrane potential in a dose-dependent manner. Additionally, eriodictyol effectively inhibited the mTOR/PI3K/Akt signalling pathway in a dose-dependent manner.

CONCLUSIONS

Based on the above findings, we conclude that eriodictyol exerts its anticancer activity through induction of mitochondrial apoptosis and G2/M cell cycle arrest and inhibition of the TOR/PI3K/Akt cascade, indicating that it may have potential as a lead compound in the treatment of lung cancer, provided further in depth studies are done.