Stability of Pattern Formation in Systems with Dynamic Source Regions.

We explain the principles of gene expression pattern stabilization in systems of interacting, diffusible morphogens, with dynamically established source regions. Using a reaction-diffusion model with a step-function production term, we identify the phase transition between low-precision indeterminate patterning and the phase in which a traveling, well-defined contact zone between two domains is formed. Our model analytically explains single- and two-gene domain dynamics and provides pattern stability conditions for all possible two-gene regulatory network motifs.

Characterization of morphology and resistance to Blumeria graminis of winter triticale monosomic addition lines with chromosome 2D of Aegilops tauschii.

KEY MESSAGE: Allocation of the chromosome 2D of Ae. tauschii in triticale background resulted in changes of its organization, what is related to varied expression of genes determining agronomically important traits. Monosomic alien addition lines (MAALs) are crucial for transfer of genes from wild relatives into cultivated varieties. This kind of genetic stocks is used for physical mapping of specific chromosomes and analyzing alien genes expression. The main aim of our study is to improve hexaploid triticale by transferring D-genome chromatin from Aegilops tauschii × Secale cereale (2n = 4x = 28, DDRR). In this paper, we demonstrate the molecular cytogenetics analysis and SSR markers screening combined with phenotype analysis and evaluation of powdery mildew infection of triticale monosomic addition lines carrying chromosome 2D of Ae. tauschii. We confirmed the inheritance of chromosome 2D from the BC2F4 to the BC2F6 generation of triticale hybrids. Moreover, we unveiled a high variable region on the short arm of chromosome 2D, where chromosome rearrangements were mapped. These events had direct influence on plant height of hybrids what might be connected with changes at Rht8 loci. We obtained 20 semi-dwarf plants of BC2F6 generation carrying 2D chromosome with the powdery mildew resistance, without changes in spike morphology, which can be used in the triticale breeding programs.

The lack of the influence of various species of Mycoplasma spp. on canine semen quality.

Mycoplasmas colonize fish, reptiles, birds and mammals, being commensals or causing diseases, sometimes severe in ruminants, swine, poultry, or wildlife animals. So far, 15 species of canine Mycoplasma spp. have been described. Conflicting results have been presented regarding the pathogenicity of Mycoplasma spp. Although many virulence factors of these bacteria have been described, they still require attention. The main aim of our study was to evaluate the presence of known canine Mycoplasmas in the male reproductive tract of clinically healthy dogs. The second aim was to check if Mycoplasma spp. cause any abnormalities in semen quality that could have further consequences and to propose the schemes for managing the carriers. 83.3% of examined dogs were Mycoplasma spp. -positive dogs, and most of them were the carriers of more than one species. Six dogs had azoospermic ejaculates. The total spermatozoa numbers were similar in Mycoplasma -positive and negative groups. Motility was slightly higher in Mycoplasma spp.-negative group, but the difference was not statistically significant. There was no significant difference in semen characteristics between the carriers and Mycoplasma spp.-negative dogs. Neither the individual species nor the number of species strains had a significant effect on sperm morphological parameters as well as viability. Semen quality parameters are not correlated with the species found on the prepuce. Over 70% Mycoplasma spp.- positive dogs have more than one species of this bacteria. Despite finding mycoplasmas in azoospermic dogs, we suggest that they were not the cause of infertility. Mycoplasma spp. could be a part of normal microbiota in canine prepuce in individuals without any clinical signs.

Small-molecule inhibitor - tyrphostin AG1296 regulates proliferation, survival and migration of rhabdomyosarcoma cells.

Rhabdomyosarcoma (RMS) is the most commonly occurring malignant soft tissue tumor in children. Despite improving its treatment methods, the current outcome in the advanced stages of this tumor is not satisfactory. RMS cells are characterized by abnormal cellular signaling due to the changes in the activity of the tyrosine kinases. Thus, substances blocking the mitogenic signal transmitted by receptors with tyrosine kinase activity raise hopes for inhibition of the uncontrolled cell growth. In this study, we examined the anticancer activity of tyrphostin AG1296, a tyrosine kinase inhibitor that binds to the intracellular domain of the PDGF (platelet-derived growth factor) receptor in human RMS alveolar and embryonal cell lines. We have discovered that tyrphostin AG1296 completely inhibited cell proliferation and effectively inhibited cell viability. Tyrphostin AG1296 induced apoptosis of the RMS cells and significantly inhibited their migration. Additionally, investigated inhibitor slightly inhibited expression of AKT and phosphorylation of ERK in alveolar RMS cells. Importantly, the inhibitor exerted also potent effects on the nanomechanical properties and cytoskeleton organization of RMS cells. To conclude, tyrphostin AG1296 is a promising compound in the treatment of alveolar RMS. Undoubtedly, a better knowledge of receptor pathomechanism of tyrosine kinases may contribute to developing new, more effective ways of RMS treatment.

Effective one-component model of binary mixture: molecular arrest induced by the spatially correlated stochastic dynamics.

Spatially correlated noise (SCN), i.e. the thermal noise that affects neighbouring particles in a similar manner, is ubiquitous in soft matter systems. In this work, we apply the over-damped SCN-driven Langevin equations as an effective, one-component model of the dynamics in dense binary mixtures. We derive the thermodynamically consistent fluctuation-dissipation relation for SCN to show that it predicts the molecular arrest resembling the glass transition, i.e. the critical slow-down of dynamics in the disordered phases. We show that the mechanism of singular dissipation is embedded in the dissipation matrix, accompanying SCN. We are also able to identify the characteristic length of collective dissipation, which diverges at critical packing. This novel physical quantity conveniently describes the difference between the ergodic and non-ergodic dynamics. The model is fully analytically solvable, one-dimensional and admits arbitrary interactions between the particles. It qualitatively reproduces several different modes of arrested disorder encountered in binary mixtures, including e.g. the re-entrant arrest. The model can be effectively compared to the mode coupling theory.

Mesenchymal Stem Cells as a Salvage Treatment for Severe Refractory Graft-vs-Host Disease in Children After Bone Marrow Transplantation.

Application of mesenchymal stem cells (MSC) enables a novel approach to the therapy of graft- vs-host disease (GVHD) after hematopoietic stem cell transplantation. Herein we present our preliminary experience with the use of allogeneic bone marrow‒derived MSC in 9 pediatric patients after hematopoietic transplantation complicated by severe acute or chronic GVHD (aGVHD, cGVHD) resistant to steroids and second-line immunosuppressants. The MSC therapy was applied concurrently with immunosuppressive treatment in 5 patients as a single infusion, in four patients as 2-6 infusions. The median dose of cells per infusion was 1.9 × 106/kg of recipient body weight (range, 0.1-6.5 × 106/kg). The median quantity of cells applied to patients was 1.2 × 106/kg (range, 0.2-30.9 × 106/kg). We did not observe any adverse symptoms of MSC therapy. Overall, partial, or complete remission (PR and CR, respectively) was obtained in 56% of patients after the first MSC infusions, and 44% after completing therapy. In those with skin involvement 50% achieved permanent CR, 38% in those with gastrointestinal manifestations, and 33% in those with liver GVHD. Three patients with overlap syndrome had amelioration, but none had permanent remission. Long-term improvement after consecutive MSC doses was observed in 3 patients. In the 4- to 8-year follow-up, 3 patients are alive and 2 have attained permanent remission. Six patients died during follow-up: 4 with aGVHD and 2 with infectous complications. Co-treatment of streoid-resistant GVHD with MSC and conventional immunosuppression can improve the outcome, although therapy regimens remain to be established.

Microwave-assisted synthesis and characterization of novel chitosan-based biomaterials for pelvic organ prolapse treatment.

Pelvic organ disorders affect up to one in four women in the United States. The prevalence of pelvic organ prolapse (POP) is increasing with each year, particularly in the setting of prolonged life expectancy and an aging population. Current treatment approaches, including polypropylene monofilaments are associated with numerous painful and worrisome side-effects. Therefore, scientists are looking for new solutions. A promising alternative to the current treatment is tissue engineering, which can be utilized to re-create support to the vagina and pelvic organs. Tissue engineering requires the use of three-dimensional scaffolds, derived from biocompatible materials. Chitosan is a natural polymer, obtained from shellfish exoskeletons. It is known for its biodegradability, lack of cytotoxicity and non-pyrogenicity. Due to the presence of free hydroxyl and amino groups, it may undergo various modifications. In this paper, we describe a new type of chitosan-based biomaterials, which can be used as a new alternative scaffold that may provide support to prolapse organs. The chitosan scaffold was obtained under microwave radiation using multifunctional amino and organic acids. We discuss the scaffold's characteristics, with an emphasis on its chemical structure and morphology. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed cross-linking processes with preservation of free amino groups. Moreover, mechanical durability, the stability and swelling ability of the scaffolds in a simulated body fluid were investigated. All of the prepared scaffolds demonstrated very good antioxidant activity and biodegradability. Importantly, the biocompatibility of chitosan scaffolds was examined on human vaginal VK2/E6E7 cell line. No evidence of toxicity was documented, and the cells maintained their presence on the studied materials. These results allude to the lack of toxicity of the scaffolds, and indicate that chitosan-based scaffold should be further investigated in in vivo studies as they may be a promising alternative treatment to pelvic organ prolapse.

Recent advances in the role of AMP-activated protein kinase in metabolic reprogramming of metastatic cancer cells: targeting cellular bioenergetics and biosynthetic pathways for anti-tumor treatment.

Growing data indicate that tumor progression and metastasis is dependent on the reprograming of cellular metabolism. Rapidly growing cancer cells undergo metabolic stress in a harsh microenvironment. AMP-activated protein kinase (AMPK) is an energy sensing factor that regulates bioenergetics and biosynthetic pathways within the cell, but its role under metastasis is in dispute. The best studied phenotype of cancer cells is aerobic glycolysis (the Warburg effect), an increased catabolism of glucose to lactate. However, glycolysis and mitochondrial oxidative phosphorylation may operate simultaneously in cancer cells. Many tumors may switch between these pathways accordingly to the current requirements. The alterations in metabolism of cancer cells combined with the overexpression of oncogenes (c-Myc) and transcription factors (Hypoxia-inducible factor 1a) confer a great advantage to malignant cells to avoid reactive oxygen species induced apoptosis. The determination of the role of AMPK network in metabolic reprogramming of metastatic cancer cells may help to identify the selective molecular targets for efficient anti-cancer therapies. In this review, we discuss the implications of AMPK activation in metabolic reprogramming of cancer cells and we present several potential therapeutic strategies targeting cancer cell metabolism. AMPK activator, biguanide metformin, either alone or in combination with other drugs, may selectively modulate signaling pathways, expresses the chemopreventive potential and can be used in current anti-cancer approaches. However, the ambiguous data suggest that the activation of AMPK may induce multiple effects and thus potential therapeutic anti-cancer approach should be carefully considered in relation to metabolic network of cancer cell signaling and other determinants such tumor stage and origin as well.

Bone marrow CD34(+) cells and megakaryoblasts secrete beta-chemokines that block infection of hematopoietic cells by M-tropic R5 HIV.

CD34(+) cells are nonpermissive to infection by HIV strains X4 and R5, despite the fact that many CD34(+) cells express high levels of the viral receptor protein CD4 and the coreceptor CXCR4 on their surface. In these cells, the co-receptor CCR5 protein, which, like CXCR4, is a chemokine receptor, is detected mainly intracellularly. We hypothesized that CD34(+) cells secrete CCR5-binding chemokines and that these factors interfere with HIV R5 interactions with these cells, possibly by binding CCR5 or by inducing its internalization. We found that human CD34(+) cells and CD34(+)KIT(+) cells, which are enriched in myeloid progenitor cells, expressed and secreted the CCR5 ligands RANTES, MIP-1alpha, and MIP-1beta and that IFN-gamma stimulated expression of these chemokines. In contrast, SDF-1, a CXCR4 ligand, was not detectable in the CD34(+)KIT(+) cells, even by RT-PCR. Conditioned media from CD34(+) cell culture significantly protected the T lymphocyte cell line PB-1 from infection by R5 but not X4 strains of HIV. Interestingly, the secretion of endogenous chemokines decreased with the maturation of CD34(+) cells, although ex vivo, expanded megakaryoblasts still secreted a significant amount of RANTES. Synthesis of CCR5-binding chemokines by human CD34(+) cells and megakaryoblasts therefore largely determines the susceptibility of these cells to infection by R5 HIV strains. We postulate that therapeutic agents that induce the endogenous synthesis of chemokines in human hematopoietic cells may protect these cells from HIV infection.

A population of very small embryonic-like (VSEL) CXCR4(+)SSEA-1(+)Oct-4+ stem cells identified in adult bone marrow.

By employing multiparameter sorting, we identified in murine bone marrow (BM) a homogenous population of rare (approximately 0.02% of BMMNC) Sca-1(+)lin(-)CD45- cells that express by RQ-PCR and immunohistochemistry markers of pluripotent stem cells (PSC) such as SSEA-1, Oct-4, Nanog and Rex-1. The direct electronmicroscopical analysis revealed that these cells are small (approximately 2-4 microm), posses large nuclei surrounded by a narrow rim of cytoplasm, and contain open-type chromatin (euchromatin) that is typical for embryonic stem cells. In vitro cultures these cells are able to differentiate into all three germ-layer lineages. The number of these cells is highest in BM from young (approximately 1-month-old) mice and decreases with age. It is also significantly diminished in short living DBA/2J mice as compared to long living B6 animals. These cells in vitro respond strongly to SDF-1, HGF/SF and LIF and express CXCR4, c-met and LIF-R, respectively, and since they adhere to fibroblasts they may be coisolated with BM adherent cells. We hypothesize that this population of Sca-1(+)lin(-)CD45- very small embryonic-like (VSEL) stem cells is deposited early during development in BM and could be a source of pluripotent stem cells for tissue/organ regeneration.

Cells enriched in markers of neural tissue-committed stem cells reside in the bone marrow and are mobilized into the peripheral blood following stroke.

The concept that bone marrow (BM)-derived cells participate in neural regeneration remains highly controversial and the identity of the specific cell type(s) involved remains unknown. We recently reported that the BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSCs), including neural TCSCs. Here, we report that these cells not only express neural lineage markers (beta-III-tubulin, Nestin, NeuN, and GFAP), but more importantly form neurospheres in vitro. These neural TCSCs are present in significant amounts in BM harvested from young mice but their abundance and responsiveness to gradients of motomorphogens, such as SDF-1, HGF, and LIF, decreases with age. FACS analysis, combined with analysis of neural markers at the mRNA and protein levels, revealed that these cells reside in the nonhematopoietic CXCR4+/Sca-1+/lin-/CD45 BM mononuclear cell fraction. Neural TCSCs are mobilized into the peripheral-blood following stroke and chemoattracted to the damaged neural tissue in an SDF-1-CXCR4-, HGF-c-Met-, and LIF-LIF-R-dependent manner. Based on these data, we hypothesize that the postnatal BM harbors a nonhematopoietic population of cells that express markers of neural TCSCs that may account for the beneficial effects of BM-derived cells in neural regeneration.

Thermodynamically consistent Langevin dynamics with spatially correlated noise predicting frictionless regime and transient attraction effect.

While the origins of temporal correlations in Langevin dynamics have been thoroughly researched, the understanding of spatially correlated noise (SCN) is rather incomplete. In particular, very little is known about the relation between friction and SCN. In this article, starting from the microscopic, deterministic model, we derive the analytical formula for the spatial correlation function in the particle-bath interactions. This expression shows that SCN is the inherent component of binary mixtures, originating from the effective (entropic) interactions. Further, employing this spatial correlation function, we postulate the thermodynamically consistent Langevin equation driven by the Gaussian SCN and calculate the adequate fluctuation-dissipation relation. The thermodynamical consistency is achieved by introducing the spatially variant friction coefficient, which can be also derived analytically. This coefficient exhibits a number of intriguing properties, e.g., the singular behavior for certain types of interactions. Eventually, we apply this new theory to the system of two charged particles in the presence of counter-ions. Such particles interact via the screened-charge Yukawa potential and the inclusion of SCN leads to the emergence of the anomalous frictionless regime. In this regime the particles can experience active propulsion leading to the transient attraction effect. This effect suggests a nonequilibrium mechanism facilitating the molecular binding of the like-charged particles.

Allocation of the S-genome chromosomes of Aegilops variabilis Eig. carrying powdery mildew resistance in triticale (× Triticosecale Wittmack).

It has been hypothesized that the powdery mildew adult plant resistance (APR) controlled by the Pm13 gene in Aegilops longissima Schweinf. & Muschl. (S(l)S(l)) has been evolutionary transferred to Aegilops variabilis Eig. (UUSS). The molecular marker analysis and the visual evaluation of powdery mildew symptoms in Ae. variabilis and the Ae. variabilis × Secale cereale amphiploid forms (2n = 6x = 42, UUSSRR) showed the presence of product that corresponded to Pm13 marker and the lower infection level compared to susceptible model, respectively. This study also describes the transfer of Ae. variabilis Eig. (2n = 4x = 28, U(v)U(v)S(v)S(v)) chromosomes, carrying powdery mildew resistance, into triticale (× Triticosecale Wittm., 2n = 6x = 42, AABBRR) using Ae. variabilis × S. cereale amphiploid forms. The individual chromosomes of Ae. variabilis, triticale 'Lamberto' and hybrids were characterized by genomic and fluorescence in situ hybridization (GISH/FISH). The chromosome configurations of obtained hybrid forms were studied at first metaphase of meiosis of pollen mother cells (PMCs) using GISH. The statistical analysis showed that the way of S-genome chromosome pairing and transmission to subsequent hybrid generations was diploid-like and had no influence on chromosome pairing of triticale chromosomes. The cytogenetic study of hybrid forms were supported by the marker-assisted selection using Pm13 marker and visual evaluation of natural infection by Blumeria graminis, that allowed to select the addition or substitution lines of hybrids carrying chromosome 3S(v) which were tolerant to the powdery mildew infection.

Transmission of the Aegilops ovata chromosomes carrying gametocidal factors in hexaploid triticale (×Triticosecale Wittm.) hybrids.

The main aim of this work was to induce the chromosome rearrangements between Aegilops ovata (UUMM) and hexaploid triticale (AABBRR) by expression of the gametocidal factor located on the chromosome 4M. The Aegilops ovata × Secale cereale (UUMMRR) amphiploids and triticale 'Moreno' were used to produce hybrids by reciprocal crosses. Chromosome dynamics was observed in subsequent generations of hybrids during mitotic metaphase of root meristems and first metaphase of meiosis of pollen mother cells. Chromosomes were identified by genomic in situ hybridisation (GISH) and fluorescence in situ hybridisation (FISH) using pTa71, pTa791, pSc119.2 and pAs1 DNA probes. It has been shown that the origin of the genetic background had an influence on Aegilops chromosome transmission. Moreover, it has been reported that the preferential transmission of chromosome 4M appeared during both androgenesis and gynogenesis. It is also hypothesised that the expression of the triticale Gc gene suppressor had an influence on the semi-fertility of hybrids but did not inhibit the chromosome rearrangements. This paper also describes the double haploid production, which enabled to obtain plants with two identical copies of triticale chromosomes with translocations of Aegilops chromatin segments.

Stem cell plasticity revisited: CXCR4-positive cells expressing mRNA for early muscle, liver and neural cells 'hide out' in the bone marrow.

It has been suggested that bone marrow (BM)-derived hematopoietic stem cells transdifferentiate into tissue-specific stem cells (the so-called phenomenon of stem cell plasticity), but the possibility of committed tissue-specific stem cells pre-existing in BM has not been given sufficient consideration. We hypothesized that (i) tissue-committed stem cells circulate at a low level in the peripheral blood (PB) under normal steady-state conditions, maintaining a pool of stem cells in peripheral tissues, and their levels increase in PB during stress/tissue injury, and (ii) they could be chemoattracted to the BM where they find a supportive environment and that the SDF-1-CXCR4 axis plays a prominent role in the homing/retention of these cells to BM niches. We performed all experiments using freshly isolated cells to exclude the potential for 'transdifferentiation' of hematopoietic stem or mesenchymal cells associated with in vitro culture systems. We detected mRNA for various early markers for muscle (Myf-5, Myo-D), neural (GFAP, nestin) and liver (CK19, fetoprotein) cells in circulating (adherent cell-depleted) PB mononuclear cells (MNC) and increased levels of expression of these markers in PB after mobilization by G-CSF (as measured using real-time RT-PCR). Furthermore, SDF-1 chemotaxis combined with real-time RT-PCR analysis revealed that (i) these early tissue-specific cells reside in normal murine BM, (ii) express CXCR4 on their surface and (iii) can be enriched (up to 60 x) after chemotaxis to an SDF-1 gradient. These cells were also highly enriched within purified populations of murine Sca-1(+) BM MNC as well as of human CD34(+)-, AC133(+)- and CXCR4-positive cells. We also found that the expression of mRNA for SDF-1 is upregulated in damaged heart, kidney and liver. Hence our data provide a new perspective on BM not only as a home for hematopoietic stem cells but also a 'hideout' for already differentiated CXCR4-positive tissue-committed stem/progenitor cells that follow an SDF-1 gradient, could be mobilized into PB, and subsequently take part in organ/tissue regeneration.

Biological significance of the expression of HIV-related chemokine coreceptors (CCR5 and CXCR4) and their ligands by human hematopoietic cell lines.

The aim of this study was to learn more about the role of the HIV-related chemokine-chemokine receptor axes in human hematopoiesis. To address this issue we phenotyped 35 selected hematopoietic cell lines for the expression of CD4, CXCR4 and CCR5. We next evaluated the functionality of these chemokine receptors by calcium flux and chemotaxis assays, and by the ability of SDF-1, MIP-1alpha, MIP-1beta and RANTES to influence the growth of the cells expressing CXCR4 and/or CCR5. Lastly, we examined whether human hematopoietic cell lines may secrete some HIV-related chemokines, and whether endogenously secreted chemokines might interfere with the infectability. of hematopoietic cells by X4 and R5 HIV strains. These results demonstrate that: (1) HIV-related receptors are widely expressed on human hematopoietic cell lines; (2) stimulation of CXCR4 by SDF-1 induces calcium flux and chemotaxis in several hematopoietic cell lines more efficiently than stimulation of CCR5 by receptor-specific beta-chemokines; (3) chemokines do not regulate proliferation of the hematopoietic cells; and finally (4) infectability of the hematopoietic cells by HIV-1 may be auto-modulated by endogenously secreted chemokines. These data shed more light on the role of HIV-related chemokine-chemokine receptors axes in human hematopoiesis and interaction of hematopoietic cells with HIV.

Bcr-abl-positive cells secrete angiogenic factors including matrix metalloproteinases and stimulate angiogenesis in vivo in Matrigel implants.

To further elucidate the role of angiogenesis in the pathogenesis of chronic myelogenous leukemia (CML) we evaluated the effects of the bcr-abl translocation on the secretion of the angiogenic factors VEGF, FGF-2, HGF, IL-8 and matrix metalloproteinases (MMPs) as well as on the angiogenic potential in vivo of bcr-abl+ cells. First, we examined murine FL5.12 cells transfected with the bcr-abl constructs p185, p210 and p230 and found that the transfected cells secreted as much as four-fold more VEGF (p185 > p210 >p230) than wild-type (wt) cells, as well as MMP-9 and MMP-2. When Matrigel fragments containing these bcr-abl+ cells were implanted subcutaneously in SCID or Balb-C mice they became significantly more vascularized and hemoglobinized than implants containing normal or wt cells (p185 > p210 > p230). Similarly, we found that myeloblasts expanded from bone marrow (BM) CD34+ cells derived from Philadelphia-positive CML patients secreted up to 10 times more VEGF, FGF-2, HGF and IL-8 compared to myeloblasts derived from normal donors' BM CD34+ cells and that BM mononuclear cells (MNC) isolated from CML patients induced vascularization of Matrigel implants in mice. Moreover, we found that peripheral blood MNC expressed MMP-2 and membrane-type (MT)1-MMP in about 50% of CML patients studied, and MMP-9 in all of them. Furthermore, VEGF stimulated the secretion of MMP-9 in these primary CML cells. We conclude that stimulation of angiogenesis by angiogenic factors, including MMPs, could play an important role in the pathogenesis of CML, suggesting that therapies targeting the newly formed endothelium could be developed for CML.

The limited infectability by R5 HIV of CD34(+) cells from thymus, cord, and peripheral blood and bone marrow is explained by their ability to produce beta-chemokines.

The resistance of human bone marrow (BM) CD34(+) cells to human immunodeficiency virus (HIV) infection is at this point not fully understood. Recently we reported that the chemokines MIP-1alpha, MIP-1beta, and RANTES secreted by BM-derived CD34(+) cells may compete with the macrophagotropic HIV (R5 HIV) strain for the CCR5 coreceptor.In this study we extended our previous observations and examined various lympho-hematopoietic CD34(+) cells isolated from thymus (Th), cord blood (CB), mobilized peripheral blood (mPB), and BM for the expression of beta-chemokines binding to CCR5, i.e., MIP-1alpha, MIP-1beta, RANTES, MCP-2, MCP-3, and MCP-4, and the alpha chemokine SDF-1 (binding to CXCR4) as these chemokines may compete with the R5 and X4 HIV strains, respectively, for entry into cells. We found that Th-, CB-, mPB-, and BM-derived CD34(+) cells express mRNA transcripts for all the beta-chemokines tested but not for SDF-1. Using sensitive ELISA assays we found that although MIP-1alpha and MIP-1beta proteins were secreted by all the lympho-hematopoietic CD34(+) cells tested, RANTES was detectable only in media conditioned by BM- and CB-derived CD34(+) cells and not Th-derived cells. However, media conditioned by BM-, mPB- and Th-derived CD34(+) cells protected the T lymphocytic cell line (PB-1) from infection by the R5 but not the X4 HIV strain. Hence this study demonstrates that beta-chemokines are secreted by lympho-hematopoietic CD34(+) cells originating from various sources and that these endogenously secreted chemokines may limit entry of the R5 HIV strain into the cells by competing for the CCR5 coreceptor.

Non-Gaussian polymers described by alpha-stable chain statistics: Model, effective interactions in binary mixtures, and application to on-surface separation.

The Gaussian chain model is the classical description of a polymeric chain, which provides analytical results regarding end-to-end distance, the distribution of segments around the mass center of a chain, coarse-grained interactions between two chains and effective interactions in binary mixtures. This hierarchy of results can be calculated thanks to the α stability of the Gaussian distribution. In this paper we show that it is possible to generalize the model of Gaussian chain to the entire class of α-stable distributions, obtaining the analogous hierarchy of results expressed by the analytical closed-form formulas in the Fourier space. This allows us to establish the α-stable chain model. We begin with reviewing the applications of Levy flights in the context of polymer sciences, which include: chains described by the heavy-tailed distributions of persistence length; polymers adsorbed to the surface; and the chains driven by a noise with power-law spatial correlations. Further, we derive the distribution of segments around the mass center of the α-stable chain and construct the coarse-grained interaction potential between two chains. These results are employed to discuss the model of binary mixture consisting of the α-stable chains. In what follows, we establish the spinodal decomposition condition generalized to the mixtures of the α-stable polymers. This condition is further applied to compare the on-surface phase separation of adsorbed polymers (which are known to be described with heavy-tailed statistics) with the phase separation condition in the bulk. Finally, we predict the four different scenarios of simultaneous mixing and demixing in the two- and three-dimensional systems.

Heparinized cadaveric organ donors (HCOD)--a potential source of hematopoietic cells for transplantation and gene therapy.

BACKGROUND: Hematopoietic stem cells (HSC) from unrelated HLA-matched heparinized cadaveric organ donors (HCOD) are a new potential source of cells for transplantation and gene therapy. In addition, these cells could also be used as adjuvant therapy to increase microchimerism and graft tolerance after transplantations of various solid organs. Our purpose was to develop an efficient method for harvesting hematopoietic cells from HCODs, METHODS: Bone marrow cells were harvested from pelvic bones and/or vertebral bodies from 50 adult HCODs before or up to 3 hr after disconnecting the donor from the respirator. Subsequently, we evaluated the hematological and gasometric parameters of aspirated marrow samples as well as the proliferative potential, viability, and expression of CD34 and AC133 antigens on these cells. RESULTS: We noticed that up to 2-3 hr after disconnecting the donor from the respirator bone marrow cavities do not clot and remain uninfected and that it is possible to aspirate bone marrow mononuclear cells in quantities sufficient to perform allotransplantation. Nevertheless, due to the developing hypoxia and acidosis of the hematopoietic microenvironment the number and proliferative potential of CD34+ and AC133+ cells gradually decreases. Hence, to obtain viable early hematopoietic cells, bone marrow should be aspirated without delay; optimally before HCOD is disconnected from the respirator or at the very latest 2 hr after organ harvest. CONCLUSIONS: Collectively, our results show that early hemopoietic cells may be efficiently harvested from HCOD in large quantities and used for research and/or transplantation purposes. We postulate to create an international network of banks in which hemopoietic stem cells from HCODs could be preserved for therapeutic purposes.