Percoll Gradient Research Articles

Role of aerobic exercise training on tumor‐infiltrated immune cells

BackgroundDespite the remarkable treatment progress in the last decades, cancer remains the second leading cause of death in the world. Therefore, strategies capable of attenuating tumor initiation, progression and aggressiveness are important for reducing incidence and mortality caused by cancer. Considering this, it is well known that aerobic exercise training (AET) promotes several beneficial adaptations in the body, and it has emerged as a possible strategy to attenuate tumor progression. However, the mechanisms underlining the beneficial effects of AET on tumor progression are still unclear. Aim: Therefore, this study intended to evaluate whether AET could positively modify the tumor microenvironment, favoring infiltration of “antitumor” immune cells, and/or reducing the amount of “protumor” immune cells, consequently attenuating tumor progression.MethodsTo test this, Balb/c mice were submitted to a moderate intensity AET (60% of maximal aerobic capacity, 5 days/week, 1 hour/day, in a treadmill) for 1 month before being inoculated with 1x106 CT26 colon carcinoma cells (subcutaneous injection). The AET protocol was maintained during tumor progression, and the last exercise session was performed 48 hours before animals were sacrificed (9 days after tumor cells inoculation). Tumor volume and body weight were measured daily. Experimental groups were divided into control (healthy sedentary mice), CT26 SED (sedentary tumor‐bearing mice) and CT26 TR (trained tumor‐bearing mice). Tumors were harvested at day 9 and digested with collagenase IV and DNAse. After that, tumor leukocytes were separated by a Percoll gradient. Tumor‐infiltrated dendritic cells, macrophages, natural killer cells (NK), and T lymphocytes were measured by flow cytometry. Statistical analysis: Anova One‐way, Duncan post hoc, p<0.05. Ethical committee approval: CEUA EEFE‐USP 2017/02.ResultsTumor‐bearing mice submitted to AET presented an attenuated tumor progression when compared with CT26 SED group, with significant reduction in tumor volume and mass (ex vivo). AET significantly increased the total amount of tumor‐infiltrated leukocytes (CD45+), which included an increase in the percentage of NK cells, total, activated and effector memory CD8+ T cells, and effector memory CD4+ T cells in CT26 TR when compared to CT26 SED. Although there were no significant changes in the tumor amount of total and activated CD4+ T cells, the CD4+/CD8+ ratio was significantly reduced in CT26 TR comparing with CT26 SED mice, suggesting that the balance between CD4+ and CD8+ T cells in trained mice tumors favored a cytotoxic/effector T lymphocyte profile. Moreover, the percentage of tumor‐infiltrated regulatory T cells (Tregs) in CT26 TR was significantly decreased when compared to CT26 SED mice. No significant changes were found for dendritic cells and macrophages (types M1 and M2).ConclusionAET increases tumor‐infiltrated amounts of cytotoxic/effector immune cells, such as NK and CD8+ T cells, while decreasing the percentage of Tregs in a colon cancer animal model. These data suggest that AET can attenuate tumor growth by modulation of tumor‐infiltrated immune cells number and profile.

Continuous Percoll Gradient Centrifugation of Erythrocytes—Explanation of Cellular Bands and Compromised Age Separation

(1) Background: When red blood cells are centrifuged in a continuous Percoll-based density gradient, they form discrete bands. While this is a popular approach for red blood cell age separation, the mechanisms involved in banding were unknown. (2) Methods: Percoll centrifugations of red blood cells were performed under various experimental conditions and the resulting distributions analyzed. The age of the red blood cells was measured by determining the protein band 4.1a to 4.1b ratio based on western blots. Red blood cell aggregates, so-called rouleaux, were monitored microscopically. A mathematical model for the centrifugation process was developed. (3) Results: The red blood cell band pattern is reproducible but re-centrifugation of sub-bands reveals a new set of bands. This is caused by red blood cell aggregation. Based on the aggregation, our mathematical model predicts the band formation. Suppression of red blood cell aggregation reduces the band formation. (4) Conclusions: The red blood cell band formation in continuous Percoll density gradients could be explained physically by red blood cell aggregate formation. This aggregate formation distorts the density-based red blood cell age separation. Suppressing aggregation by osmotic swelling has a more severe effect on compromising the RBC age separation to a higher degree.

A novel Ush transcription factor involving in hematopoiesis of Eriocheir sinensis.

The FOG transcriptional factor is a co-regulator that recognizes and binds to the GATA N-terminal zinc-finger domain and participates in hemocyte production and differentiation. In this study, an FOG-like gene, Ush, was characterized from Eriocheir sinensis, which consists of an 897bp full-length open reading frame, encoding a polypeptide of 298 amino acids with four ZnF_C2H2 domains. The EsUsh mRNA transcripts were mainly expressed in the hematopoietic tissue (HPT) and hemocytes, and were significantly higher in hyalinocytes than semi-granulocytes and granulocytes, which were separated by Percoll gradient centrifugation. The transcription levels of EsUsh were found to be significantly upregulated in HPT, but downregulated in hemocytes after exsanguination. By using flow cytometry to determine the percentage of hemocyte sub-population after exsanguination, the percentage of hyalinocytes was found to significantly downregulated, while the percentage of granulocytes was significantly upregulated. Silencing EsUsh by dsRNA interference significantly decreased the percentage of hyalinocytes and small granulocytes, and increased the percentage of medium granulocytes and large granulocytes. Such findings suggest that EsUsh might be involved in hemocyte production and differentiation, especially in promoting hyalinocyte formation and limiting granulocyte generation and differentiation.

Human live spermatozoa morphology assessment using digital holographic microscopy

Digital holographic microscopy (DHM) was applied for the morphological assessment of live intact spermatozoa from fertile and infertile men directly after semen liquefaction. This method allowed us to study the sperm population directly from the sample droplet and not only from the focal plane of the microscope as in classical optical microscopy. The newly implemented 3-dimensional sperm morphological parameters (head height, acrosome/nucleus height, head/midpiece height) were included in morphological assessment of semen samples from fertile and infertile individuals. The values of the 3D parameters were less variable in fertile men than for infertile ones. DHM was also used to compare the morphological profiles of spermatozoa after applying the “swim-up” and gradient centrifugation techniques. During selection, the most statistically significant differences were observed after separation with a Percoll gradient of 90% and a 60-min “swim-up” procedure versus ‘native’ unfractionated samples. This shows that the developed methodology can be efficiently used for the selection of morphologically sound spermatozoa. The motility type for each spermatozoon was also assessed. The results indicate that the extension of the number of morphological parameters with new 3D parameters and the simultaneous assessment of sperm motility may be valuable addition to sperm examination.

Comparison of six methods for Loa loa genomic DNA extraction.

Good-quality and sufficient DNA is essential for diagnostics and vaccine development. We aimed to compare six DNA extraction techniques applied to Loa loa microfilariae in order to evaluate the purity and integrity of extracts in terms of quality and quantity. The microfilariae were purified via a Percoll gradient procedure with blood from hyper-microfilaremic individuals (> 30,000 microfilaria [mf]/ml). DNA extraction was carried out in duplicate at a rate of 350,000 mf/tube for each technique: phenol/chloroform, commercial Qiagen kit, salting out, Tris-EDTA, methanol, and cetyltrimethylammonium bromide (CTAB). The integrity, purity, concentration, and quality of the DNA extracts were successively verified by agarose gel electrophoresis, spectrophotometry (A260/A280 and A260/A230 wavelength ratio), Qubit fluorometry, and endonuclease and polymerase activity. The six techniques were compared on the basis of the following parameters: concentration, purity, efficiency, effectiveness, integrity, safety of the technique, as well as cost and duration of the protocol. The ratios of the optical densities of the extracts A260/A280 and A260/A230 were, respectively: phenol/chloroform (1.82; 1.11), Qiagen (1.93; 1.36), salting-out (1.9; 2.04), Tris-EDTA (1.99; 1.183), methanol (2.126; 1.343), and CTAB (2.01; 2.426). The DNA yield was: phenol/chloroform (3.920 μg), Qiagen (10.280 μg), salting-out (10.390 μg), Tris-EDTA (0.5528 μg), methanol (0.1036 μg), and CTAB (1.115 μg). Endonuclease and polymerase activity was demonstrated by digestion of DNA and through amplicons obtained via polymerase chain reaction assays with phenol/chloroform, Qiagen, and salting-out extracts. The phenol/chloroform, Qiagen, and salting-out DNA extracts were all of good quality. Salting out had the best yield followed by Qiagen and then phenol/chloroform. Endonuclease and polymerase activity was effective in all three extracts despite the presence of some contaminants. These methods are therefore suitable for the extraction of DNA from Loa loa microfilariae. Tris-EDTA and methanol did not show adequate sensitivity, while CTAB was found to be unsuitable.

Development of a microfluidic system structured on a modified polydimethylsiloxane device for the selection of bovine epididymal spermatozoa

Microfluidic systems are on the rise in several studies that evaluate reproductive cells. However, the material used for manufacturing can still be considered relatively expensive. The objective of this study was to develop a new microfluidic device, using a modified polydimethylsiloxane ((PDMS) Silpuran®), test its viability and carry out a selection of bovine sperm. Sperm was collected from epididymis (n = 10) and evaluated at different incubation times (60 min, 120 min, 180 min) to assess polydimethylsiloxane toxicity, where a tube was used as a control and the microfluidic device as treatment. An additional ten epididymis were used for the sperm selection test, which utilized four types of solutions: in vitro maturation medium (IVM) with and without oocyte, progesterone and saline solution (SS). The Percoll gradient was used as a control and the microfluidic device as treatment. The kinetic parameters of sperm were evaluated using the computer-assisted semen analysis (CASA). Morphology was performed with Bengal Rose, the integrity, and viability of the sperm using the hypoosmotic test and fluorescent microscopy probes, respectively. Mann-Whitney test was used in the first experiment, Kruskall-Wallis variance analysis tests with post hoc and Student-Newman-Keuls used in the second experiment. Regarding the non-toxic effects, most motility parameters demonstrated the superiority of the microfluidic device compared to the control. In the second experiment, the sperm showed equivalence between the microfluidic device and the Percoll gradient Silpuran® PDMS was not toxic to the cells and can be efficient for selecting bovine sperm, achieving better results in a medium for IVM with or without oocytes.

Two modified density gradient centrifugation methods facilitate the isolation of mouse Leydig cells

Preparation of sufficient mouse Leydig cells (LCs) with high purity is a prerequisite for investigations of the biological/pathological functions of LCs in mouse models. Density gradient centrifugation based on discontinuous Percoll gradients is an effective method (defined as regular method) for LC isolation. In this study, we developed two modified methods for LC isolation and compared their performance with that of the regular method. Modified method 1 integrated the crude LCs into the 50% Percoll solution before centrifugation. Modified method 2 sequentially used 50 and 60% Percoll solutions to isolate LCs. The purity of LCs was approximately 88.4, 91.3, and 79.7% derived from the regular, modified 1, and modified 2 methods, respectively. The yields of LCs in the same respective order were approximately 1.7 × 105, 3.9 × 105, and 11.9 × 105 cells per 108 interstitial cells input. Modified method 1 attained higher purity and yields than those of the regular method. Although the purity of LCs was relatively low for modified method 2, it could be used before further purification by, for example, fluorescence-activated or magnetic-activated cell sorting, owing to its simplicity and high yields. Therefore, our study provided alternative methods to facilitate LC isolation in mice.

Abstract P1-11-02: Parity reduces the risk of mammary cancer by altering the characteristics of mammary stem cells

Abstract Introduction: Parous rats treated with chemical carcinogen develop a low incidence of overt mammary cancers compared to that in carcinogen-treated nulliparous rats. Examination of the mammary glands at necropsy 12 months after carcinogen treatment revealed that a high percentage of the parous rats had preneoplastic mammary lesions. These studies demonstrate that in parous rats, initiation of mammary carcinogenesis occurs at a high efficiency, although the systemic and local environment is inadequate for promotion to overt cancers. Stem cells have been implicated as the target cells for tumor initiation. In this study we investigated if parity altered the mammary stem cells. Materials and Methods: Nulliparous and parous parous were euthanized and the preneoplastic mammary lesions were surgically removed under a dissection microscope. The lesions were dissociated using the collagenase digestion method. After digestion the cells were separated using the percoll gradient. The enriched epithelial cell population was cultured and sorted for stem cells using ALDH, CD44, CD24 as markers. Sphere formation assays was established using 5000 cells/well on ultra-low attachment 6-well plates. For self-renewal assay, the 1st generation spheres was dissociated using Accutase, counted and replated in the same media as single cells with a plating density of 5000 cells/well. The same process was followed for the subsequent generations. In another set of experiments stem cells were treated with growth hormone (GH) and prolactin (PRL) to identify the role of these two mammogenic hormones on the mammary stem cells. Using the stem cells we performed the limiting dilution analysis to estimate the tumor forming capacity of the initiated mammary stem cells. Results: The sphere forming capacity of parous mammary stem cells was significantly reduced compared to nulliparous mammary stem cells. In addition, the self-renewing abilities were also remarkably decreased. Treatment with GH and PRL restored the sphere forming and self-renewing capabilities of parous mammary stem cells similar to nulliparous mammary stem cells. Further, the limiting dilution assay also demonstrated that parity altered the mammary stem cells making them less capable of forming tumors. Conclusion: Parity significantly altered the characteristics of the mammary stem cells rendering them to be resistant to mammary tumorigenesis. GH and PRL were able to increase stemness and favor mammary tumorigenesis in parous rats. Further research is required to delineate the mechanism by which parity alters the stemness characteristics of mammary stem cells reducing the risk of mammary cancers. Citation Format: Ramadevi Subramani, Adriana Estrada, Sheryl Rodriguez, Seeta Poudel, Jesse Foskey, Cynthia Jimenez, Kenneth Smith, Mark Shahinian, Abdallah Yazadi, Tugba Mehmetoglu-Gurbuz, Jackelyn Rocha, Rajkumar Lakshmanaswamy. Parity reduces the risk of mammary cancer by altering the characteristics of mammary stem cells [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-11-02.

Primary culture of germ cells that portray stem cell characteristics and recipient preparation for autologous transplantation in the rhesus monkey

Fertility preservation for prepubertal cancer patients prior to oncologic treatment is an emerging issue, and non‐human primates are considered to constitute suitable models due to the limited availability of human testicular tissues. However, the feasibility of spermatogonial stem cell (SSC) propagation in vitro and autologous testicular germ cell transplantation in vivo requires further exploration in monkeys. Herein, we characterized germ cells in macaque testes at 6 months (M), 18 M and 60 M of age, and effectively isolated the spermatogenic cells (including the spermatogonia) from macaque testes with high purity (over 80%) using combined approaches of STA‐PUT separation, Percoll gradients and differential plating. We also generated recipient monkey testes with ablated endogenous spermatogenesis using the alkylating agent busulfan in six macaques, and successfully mimicked autologous cell transplantation in the testes under ultrasonographic guidance. The use of trypan blue led to successful intratubular injection in 4 of 4 testes. Although SSCs in culture showed no significant propagation, we were able to maintain monkey testicular germ cells with stem cell characteristics for up to 3 weeks. Collectively, these data provided meaningful information for future fertility preservation and SSC studies on both non‐human primates and humans.

Growth and division mechanisms by which genetic resisters emerge from the rifampicin-surviving population of differentially antibiotic-susceptible mycobacterial subpopulations.

We recently reported the de novo emergence of unusually high numbers of antibiotic resisters from the in vitro cultures of Mycobacterium tuberculosis and Mycobacterium smegmatis surviving in the presence of minimum bactericidal concentration (MBC) of antituberculosis antibiotics. The resisters emerged due to multiple asymmetric divisions of elongated mother cells containing multiple nucleoids and multiple septae. We had earlier found a minor subpopulation of short-sized cells (SCs) and a major subpopulation of normal-sized cells (NCs) (10% and 90%, respectively, of the whole population), with significant difference in antibiotic susceptibility and resister generation frequency, in the in vitro cultures of M. tuberculosis, M. smegmatis, and Mycobacterium xenopi, as well as in pulmonary tuberculosis patients' sputum. However, the mechanisms of growth and division promoting the emergence of antibiotic resisters from these subpopulations remained unknown. Therefore, here, we took up the first-time study to find out the mechanism of growth and division by which antibiotic resisters emerge from the antibiotic-surviving population of the two subpopulations of M. smegmatis. M. smegmatis SCs and NCs were fractionated from mid-log phase cultures using Percoll gradient centrifugation; their purity was checked and exposed to 10×, 2×, and 0.4× MBC of rifampicin for 120 h. The colony-forming units (CFUs) were determined on rifampicin-free plates for the total population and on rifampicin-containing plates for scoring rifampicin resisters. The phenotype and the morphology of the cells at various stages of the exposure were determined using transmission electron microscopy. The dynamic growth and division mechanisms of the cells to emerge as rifampicin resisters were monitored using live-cell time-lapse imaging. The rifampicin resisters were sequenced for mutations in the rifampicin resistance determining region of rpoB gene. Statistical significance was calculated using two-tailed paired t-test, with *P ≤ 0.05 and **P ≤ 0.01. Multinucleated and multiseptated elongated cells emerged from their respective antibiotic-surviving populations. They produced a large number of sibling-daughter cells through multiple asymmetric divisions in short durations, showing abnormally high spurts in CFUs of antibiotic resisters. The CFUs were several-fold higher than that expected from the mass-doubling time of the subpopulations. Despite this commonality, the subpopulations showed specific differences in their response to different multiples of their respective MBC of rifampicin. Mycobacterial subpopulations come out of rifampicin stress by undergoing multiple nucleoid replications, multiple septation for nucleoid segregation, and acquisition of antibiotic target-specific mutations, followed by multiple asymmetric divisions to generate unusually a large number of rifampicin resisters. Because we had earlier shown that SCs and NCs are present in the pulmonary tuberculosis patients' sputum, the present findings have clinical relevance on the mechanism of emergence of antibiotic-resistant strains from mycobacterial subpopulations.

Improved quality of Kambing Kacang sexing frozen semen with the addition of green tea extract.

The objective of this study was to determine the effect of adding various doses of green tea extract to the semen of Kacang goats during the sexing process on motility, viability, membrane integrity, malondialdehide (MDA), and deoxyribonucleic acid (DNA) fragmentation. It started with the containment of the semen of the Kacang goat, followed by macroscopic and microscopic examinations. If the semen was considered viable, a diluter that had been added with various doses of green tea extract would be added to the semen. After that, sexing was carried out using the percoll gradient density medium. Next, the sexed semen was cryopreserved in liquid nitrogen. Then, an examination of motility, viability, membrane integrity, MDA, and DNA fragmentation was conducted. There was a significant difference between the control and treatment (p ≤ 0.05). The highest result was obtained in the treatment of adding 0.05 mg of green tea extract/100 ml of Andromed®. The addition of green tea extract can improve the quality of the sexed semen of the Kacang goat after it has been cryopreserved.

Neuroprotective evaluation of novel substituted 1,3,4-oxadiazole and aroylhydrazone derivatives

The paper reports on the facile and convenient synthesis of a series of novel 2,5-substituted 1,3,4-oxadiazoles 3a-f and that of aroylhydrazone-based molecular hybrids 5a-g from readily available starting materials. The structure of the compounds was confirmed by IR, 1H NMR, 13C NMR and HRESI-MS spectral data. The toxicological potential of the compounds was evaluated by monitoring the synaptosomal viability and the levels of reduced glutathione in rat brain synaptosomes, isolated by Percoll gradient. The neuroprotective effects were assessed in vitro in a model of 6-hydroxydopamine-induced neurotoxicity. Administered alone, at a concentration of 40 µM, most of the 1,3,4-oxadiazole derivatives and all of the hydrazone derivatives exhibited weak statistically significant neurotoxic effects, compared to the control. Two of the compounds from the novel oxadiazoles 3a and 3d did not have any toxicity. In a model of 6-OHDA-induced oxidative stress, again 3a and 3d and all aroylhydrazone derivatives 5a-g revealed statistically significant neuroprotective effect by preserving the synaptosomal viability and the level of reduced glutathione, against the toxic agent. Some of the compounds may have neuroprotective effects due to possible stabilization of the synaptosomal membrane and/or because of the preserved reduced glutathione. Additionally, all the compounds display a good predicted ADME profile.

Isolation and Measurement of Respiration and Structural Studies of Purified Mitochondria from Heterotrophic Plant Tissues.

Mitochondria are the power houses of eukaryotic cells. These organelles contain various oxidoreductase complexes. Electron transfer from different reducing equivalents channeled via these complexes drives proton translocation across the inner mitochondrial membrane, leading to ATP generation. Plant mitochondria contain alternative NAD(P)H dehydrogenases, alternative oxidase, and uncoupling protein, and TCA cycle enzymes are located in their matrix. Apart from ATP production, mitochondria are also involved in synthesis of vitamins and cofactors and participate in fatty acid, nucleotide, photorespiratory, and antioxidant metabolism. Recent emerging evidence suggests that mitochondria play a role in redox signaling and generation of reactive oxygen and nitrogen species. For mitochondrial studies, it is essential to isolate physiologically active mitochondria with good structural integrity. In this article, we explain a detailed procedure for isolation of mitochondria from various heterotrophic tissues, such as germinating chickpea seeds, potato tubers, and cauliflower florets. This procedure requires discontinuous Percoll gradient centrifugation and can give a good yield of mitochondria, in the range of 4 to 8 mg per 50 g tissue with active respiratory capacity. After MitoTracker staining, isolated mitochondria can be visualized by using a confocal microscope. The structure of mitochondria can be monitored by scanning electron microscopy. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Isolation of mitochondria from germinating chickpea seeds, potato tubers, and cauliflower florets Basic Protocol 2: Quantification of mitochondrial protein concentration by Bradford assay Basic Protocol 3: Quantification of mitochondrial respiration using single-channel free-radical analyzer Basic Protocol 4: Staining of mitochondria and confocal imaging Basic Protocol 5: Visualization of isolated mitochondria under scanning electron microscope.

Proteomic Analysis of Trichomonas vaginalis Phagolysosome, Lysosomal Targeting, and Unconventional Secretion of Cysteine Peptidases

The lysosome represents a central degradative compartment of eukaryote cells, yet little is known about the biogenesis and function of this organelle in parasitic protists. Whereas the mannose 6-phosphate (M6P)-dependent system is dominant for lysosomal targeting in metazoans, oligosaccharide-independent sorting has been reported in other eukaryotes. In this study, we investigated the phagolysosomal proteome of the human parasite Trichomonas vaginalis, its protein targeting and the involvement of lysosomes in hydrolase secretion. The organelles were purified using Percoll and OptiPrep gradient centrifugation and a novel purification protocol based on the phagocytosis of lactoferrin-covered magnetic nanoparticles. The analysis resulted in a lysosomal proteome of 462 proteins, which were sorted into 21 classes. Hydrolases represented the largest functional class and included proteases, lipases, phosphatases, and glycosidases. Identification of a large set of proteins involved in vesicular trafficking (80) and turnover of actin cytoskeleton rearrangement (29) indicate a dynamic phagolysosomal compartment. Several cysteine proteases such as TvCP2 were previously shown to be secreted. Our experiments showed that secretion of TvCP2 was strongly inhibited by chloroquine, which increases intralysosomal pH, thus indicating that TvCP2 secretion occurs through lysosomes rather than the classical secretory pathway. Unexpectedly, we identified divergent homologues of the M6P receptor TvMPR in the phagolysosomal proteome, although T. vaginalis lacks enzymes for M6P formation. To test whether oligosaccharides are involved in lysosomal targeting, we selected the lysosome-resident cysteine protease CLCP, which possesses two glycosylation sites. Mutation of any of the sites redirected CLCP to the secretory pathway. Similarly, the introduction of glycosylation sites to secreted β-amylase redirected this protein to lysosomes. Thus, unlike other parasitic protists, T. vaginalis seems to utilize glycosylation as a recognition marker for lysosomal hydrolases. Our findings provide the first insight into the complexity of T. vaginalis phagolysosomes, their biogenesis, and role in the unconventional secretion of cysteine peptidases.

Extracorporeal Photopheresis Induces Netosis in Neutrophils Derived from Patients with Graft-Versus-Host Disease

IntroductionExtracorporeal photopheresis (ECP) serves as a second line treatment for patients with acute or chronic graft versus host disease (GVHD) and demonstrates efficacy in ameliorating GVHD in this setting. The mechanism by which ECP acts against GVHD has not been fully elucidated yet. Preliminary data point to an association between GVHD and increased neutrophil extracellular trap (NET) formation (NETosis) although much is unknown regarding the pathologic implication of this association. In this study we performed a preliminary assessment of the influence of ECP on NETosis among patients with GVHD.MethodsSix patients after allogeneic transplantation treated with ECP for severe GVHD post allogeneic transplant at the Rabin Medical Center in Israel were enrolled to the study. Blood samples were obtained at 3 different time points: before an ECP cycle, immediately after the end of the ECP and 24h after the initiation of the ECP cycle. Neutrophils were obtained from whole blood samples using a percoll gradient. NETosis was assessed by measurement of neutrophil elastase activity using a commercial NETosis assay kit by Cayman Chemical and by immunofluorescence staining for DNA (DAPI (4',6-diamidino-2-phenylindole)) and for citrullinated H3 (H3Cit), a marker of NET formation. All assessments were executed in unstimulated neutrophils and in neutrophils that were stimulated with phorbol myristate acetate (PMA)(100nmol) for 4 hours.ResultsSix patients (4 males) with chronic GVHD were included in the study. The underlying hematologic disease was acute myeloid leukemia (AML) in four patients, B-cell acute lymphocytic leukemia (B-ALL) and myelodysplastic syndrome (MDS) each in one patient. ECP was executed for moderate to severe GVHD. We observed a sharp increase in the formation of NETs following treatment with ECP among all study participants. The level of neutrophil elastase activity was significantly elevated from a mean value of 2.21mU/mL (±0.6mU/mL) at baseline to a mean value of 13.82mU/mL (±5.54mU/mL) immediately after the treatment (p-value=0.0022). The mean level of neutrophil elastase activity was significantly elevated to a mean peak value of 17.35mU/mL (±10.74mU/mL) 24h following the initiation of the ECP cycle (p-value 0.0063 for the difference between the first and the last time points). Pre-incubation of the neutrophils with PMA yielded similar results, as the mean neutrophil elastase activity was 6.05mU/mL (±3.63mU/mL), 20.16mU/mL (±6.72mU/mL), and 24.57mU/mL (±13.59mU/mL) before the ECP cycle initiation, immediately after treatment, and 24h following ECP onset, respectively (Figure 1). In agreement, the expression of H3cit was also increased in neutrophils derived from patients with GVHD after ECP treatment (Figure 2).ConclusionOur preliminary data indicate that ECP induces NET formation among patients with GVHD. NETosis might play a role in the therapeutic effects of ECP in this setting. These initial results might set the stage for future studies in this field. [Display omitted] DisclosuresGoldberg: MSD Israel: Consultancy. Yeshurun: Astellas: Consultancy; Janssen: Consultancy. Wolach: Janssen: Consultancy; Abbvie: Consultancy, Honoraria, Research Funding; Astellas: Consultancy; Amgen: Research Funding; Novartis: Consultancy; Neopharm: Consultancy.

Isolation of Highly Purified, Intact, and Functional Mitochondria from Potato Tubers Using a Two-in-One Percoll Density Gradient.

The isolation of mitochondria from potato tubers (Solanum tuberosum L.) is described, but the methodology can easily be adapted to other storage tissues. After homogenization of the tissue, filtration and differential centrifugation, the key step is a Percoll density gradient centrifugation. The Percoll gradient contains two parts: a bottom part containing Percoll in 0.3M sucrose, and a slightly less dense top part containing Percoll in 0.3M mannitol. After centrifugation, a density gradient is formed that is almost linear in the central part, and this is where the band containing the purified intact mitochondria is formed. This method makes it possible to process large amounts of plant material (2-6kg) and saves at least 1.5h on the preparation time compared to methods where two consecutive purification methods are used. Nonetheless, it yields large amounts of mitochondria (50-125mg protein) of very high purity, intactness and functionality.

​Spermatozoa Sorting Techniques for the Sex Pre-selection: A Review

Furtherance of sex pre-selection techniques is extremely beneficial for the farm productivity and economic growth of the country. Several techniques such as flow cytometry, swim-up, percoll gradient centrifugation, lumisort and immunogenic spermatozoa sexing developed so far are reviewed with their principles, advantages, disadvantages and possible ways for developing a highly reliable and efficient technique to achieve success in obtaining offspring of the desired sex. Out of all these techniques available till now, sorting X- and Y- spermatozoa using fluorescence-activated cell sorter (FACS) is the most successful and commercially available technique, which employs sorting of spermatozoa based on DNA content. Despite its effectiveness, there are disadvantages concerning cost, sperm damage, trained technical person, low conception rate, etc. An alternative approach that might have potential significance could be the identification of sex-specific membrane marker proteins for the immunological method of spermatozoa sorting.

Isolation of microglia from retinas of chronic ocular hypertensive rats.

Microglia are the principal glial cells involved in the processes of immune inflammation within both retina and optic nerve, especially under the context of glaucomatous neuropathy. Considering the distinguishing role of retinal microglia in glaucoma and the lack of established protocol for microglia isolation from animal glaucoma model, the present study aimed to develop and validate a method with characteristics of both simplicity and efficiency for retinal microglia isolation from chronic ocular hypertensive (COH) rats. A Percoll gradient of various concentrations was used to separate microglia from whole retinal cells of the COH rats and control group. The finally isolated microglia were identified by CD11b and Iba-1 immunofluorescence staining, and the cell viability was determined by trypan blue staining. Additionally, the proportion of microglia in the whole retina cells was identified by flow cytometry. Results showed that the survival rates of isolated retinal microglia with the Percoll gradient method were 67.2 ± 4% and 67.6 ± 3% in control and COH groups, respectively. The proportion of the microglia population in the whole retinal cells was about 0.4–0.93%. To conclude, the present study confirmed that the application of Percoll gradient could effectively separate microglia from retinas of COH rats, which will probably enrich the tool kit for basic researchers of glaucoma specialty and help with scientific investigations.

Red blood cell ATP release correlates with red blood cell hemolysis.

The precise matching of blood flow to skeletal muscle during exercise remains an important area of investigation. Release of adenosine triphosphate (ATP) from red blood cells (RBCs) is postulated as a mediator of peripheral vascular tone in response to shear stress, hypoxia, and mechanical deformation. We tested the following hypotheses: 1) RBCs of different densities contain different quantities of ATP; 2) hypoxia is a stimulus for ATP release from RBCs; and 3) hypoxic ATP release from RBCs is related to RBC lysis. Human blood was drawn from male and female volunteers (n = 11); the RBCs were isolated and washed. A Percoll gradient was used to separate RBCs based on cellular density. Density groups were then resuspended to 4% hematocrit and exposed to normoxia or hypoxia in a tonometer. Equilibrated samples were drawn and centrifuged; paired analyses of ATP (luminescence via a luciferase-catalyzed reaction) and hemolysis (Harboe spectrophotometric absorbance assay) were measured in the supernatant. ATP release was not different among low-density cells versus middle-density versus high-density cells. Similarly, hemoglobin (Hb) release was not different among the red blood cell subsets. No difference was found for either ATP release or Hb release following matched exposure to normoxic or hypoxic gas. The concentrations of ATP and Hb for all subsets combined were linearly correlated (r = 0.59, P ≤ 0.001). With simultaneous probing for Hb and ATP in the supernatant of each sample, we conclude that ATP release from RBCs can be explained by hemolysis and that hypoxia per se does not stimulate either ATP release or Hb release from RBCs.

EFFECT OF THE USE OF TWO SPERM SELECTION TECHNIQUES FOR IN VITRO PRODUCTION OF ALPACA EMBRYOS

The objective of this research was to evaluate the effect of the use of two sperm selection techniques for in vitro production of alpaca embryos. The ovaries and testis were collected from the local slaughterhouse and transport to 37 ° C in saline solution (0.9%) supplemented with gentamicin. Quality I, II and II oocytes were incubated in a maturation medium for 32 h at 38.5 ° C and 5% O2 and 5% CO2. For in vitro fertilization, sperm from the epididymis were selected using the Percoll gradient and Swim up technique. 18h after the oocytes were incubated with the sperm, these were denuded from the cumulus cells and cultured in SOFaa culture medium for 7 days. Morula and blastocyst rate and their morphological quality are evaluated at day 7 of culture. From a total of 370 ovaries, 1,137 oocytes were recovered, making an average of 3.6 oocytes / ovary. After the maturation and fertilization process and in vitro culture, the blastocyst rate was 8.43 ± 6.04% and 3.89 ± 1.75%, for oocytes fertilized with sperm selected with Percoll gradient and Swim up, respectively, not finding significant statistical differences (p> 0.05), between the groups. In conclusion, the in vitro fertilization of alpaca oocytes with spermatozoa selected with two selection techniques (percoll and swim up) did not significantly influence the quantity and quality of morulae and blastocysts at day 7 of embryo culture.