Hematopoietic progenitors polarize in contact with bone marrow stromal cells in response to SDF1

The fate of hematopoietic stem and progenitor cells (HSPCs) is regulated by their interaction with stromal cells in the bone marrow. However, the cellular mechanisms regulating HSPC interaction with these cells and their potential impact on HSPC polarity are still poorly understood. Here we evaluated the impact of cell–cell contacts with osteoblasts or endothelial cells on the polarity of HSPC. We found that an HSPC can form a discrete contact site that leads to the extensive polarization of its cytoskeleton architecture. Notably, the centrosome was located in proximity to the contact site. The capacity of HSPCs to polarize in contact with stromal cells of the bone marrow appeared to be specific, as it was not observed in primary lymphoid or myeloid cells or in HSPCs in contact with skin fibroblasts. The receptors ICAM, VCAM, and SDF1 were identified in the polarizing contact. Only SDF1 was independently capable of inducing the polarization of the centrosome–microtubule network.     

Cattaneo-Christov Heat Flux Model for MHD Three-Dimensional Flow of Maxwell Fluid over a Stretching Sheet

This letter investigates the MHD three-dimensional flow of upper-convected Maxwell (UCM) fluid over a bi-directional stretching surface by considering the Cattaneo-Christov heat flux model. This model has tendency to capture the characteristics of thermal relaxation time. The governing partial differential equations even after employing the boundary layer approximations are non linear. Accurate analytic solutions for velocity and temperature distributions are computed through well-known homotopy analysis method (HAM). It is noticed that velocity decreases and temperature rises when stronger magnetic field strength is accounted. Penetration depth of temperature is a decreasing function of thermal relaxation time. The analysis for classical Fourier heat conduction law can be obtained as a special case of the present work. To our knowledge, the Cattaneo-Christov heat flux model law for three-dimensional viscoelastic flow problem is just introduced here.     

Direct non-insect-vector transmission of Leishmania parasites in mice

Animal to animal non-vector transmission of Leishmania major was investigated in Balb/c mice, a strain known for its susceptibility to this parasite. Both overt or inapparent infection (documented by positive spleen cultures) was possible after prolonged contact with infected animals. Similarly transmission of infection from infected mothers to their offspring was documented.     

Additional stabilization of stem bromelain coupled to a thermosensitive polymer by uniform orientation and using polyclonal antibodies

Stem bromelain was covalently coupled to a thermosensitive polymer of N-isopropylacrylamide (p(NIPAm)) either through the amino groups of the enzyme (randomly coupled) or via the lone oligosaccharide chain (uniformly coupled). The enzyme coupled via the oligosaccharide chain exhibited better access to the substrate casein as compared to the preparation in which the amino groups formed the point of contact between the enzyme and the polymer. Native bromelain exhibited a pH optimum of 8.0 and a broad pH-activity profile. The polymer-coupled preparations exhibited broader pH-activity profiles and shifting of pH optimum to 10.0 at 35°C. At 25°C, the shifting of pH optimum was observed for the randomly coupled enzyme only. The temperature-activity profiles of bromelain coupled to p(NIPAm) also showed appreciable broadening and the preparations retained greater fraction of maximum activity above the temperature optimum. The optimum temperature of the uniformly oriented preparation also rose to 70°C. Inactivation rates of the polymer-coupled bromelain were remarkably low at 60°C as compared to the native protease, and binding of antibromelain antibodies improved the resistance to inactivation of the polymer-coupled preparations. The cleavage patterns of hemoglobin and IgG by the native bromelain and the polymer-coupled preparations were comparable. Published in Russian in Biokhimiya, 2007, Vol. 72, No. 3, pp. 375–382.     

HLA class II allele frequencies in the Lebanese population

Aims

Being one of the most polymorphic genetic systems , the Human Leukocyte Antigen system is divided into class I (HLA-A, HLA-B and HLA-C) and class II (HLA-DP, -DQ and -DR). This study is the first and largest of its kind to describe the distribution of HLA-DQB1 and HLA-DRB1 alleles in Lebanon and the region.

Methods

Respectively, 560 and 563 Lebanese individuals referred for HLA typing and possible bone marrow/kidney donation were tested for HLA-DQB1 and HLA-DRB1 alleles using the polymerase chain reaction/sequence specific priming (PCR-SSP) method.

Results

Our data were compared to that of several populations with interesting common findings between the Lebanese, Jordanian, Bahraini, Saudi, Kuwaiti, Tunisian, Korean, Japanese, Thai, Irish, Bulgarian and Polish populations.

Conclusion

These data about the Lebanese population are going to aid future researchers to study the relation of HLA-DQB1 and HLA-DRB1 alleles with major and common diseases in the Lebanese population and will add to the available international literature associated with these loci. In addition it will serve as a reference for the future national bone marrow registry program in our country. We also reviewed the literature for the described association between HLA-DRB1 and -DQB1 loci and different disease entities.     

Natural Killer Cell Immunoglobulin-like Receptor (KIR) genotypes in Follicular Lymphoma patients: Results of a pilot study

Aims

The Natural Killer Cell Immunoglobulin-like Receptor (KIR) genotype profiling in Follicular Lymphoma has not been reported before in the literature.

Materials and methods

DNA extracted from 20 Follicular Lymphoma patients and 62 healthy controls was analyzed for KIR genotyping using a polymerase chain reaction/sequence specific primers technique (PCR/SSP) for the presence of 16 KIR gene and pseudogene loci.

Results

The AA, AB, and BB genotype frequencies were, respectively, 20%, 60% and 20% with an A:B ratio of 1:1. KIR 2DL4, KIR 3DL2, KIR 3DL3, and KIR 3DP1*003 were presented in all individuals. No significant difference between patients and controls was detected.

Conclusion

KIR genotyping profile does not seem to be associated with Follicular Lymphoma. The results presented in this pilot research represent the first international report about this important clinical entity.     

An analytical method for the measurement of acid metabolites of tryptophan-NAD pathway and related acids in urine

An analytical method has been developed for the measurements of five urinary acids namely, quinolinic acid, picolinic acid, nicotinic acid, 2-pyridylacetic acid and 3-pyridylacetic acid. The high performance liquid chromatograph–electrospray ionization mass spectrometry was operated in positive polarity under selected ion monitoring mode, with a column flow rate of 0.2 ml/min and an injection volume of 20 μl. The method used isotope-labelled picolinic acid (PA-d₄) and nicotinic acid (NA-d₄) as internal standards for the quantification. The sample preparation involved parallel use of two different types of mixed-mode solid phase extraction cartridges (Strata-X-AW for the extraction of quinolinic acid, and Strata-X-C for the remaining acids). Quantitative analysis of five target acids in several human and rat urine samples showed that the levels of acids were relatively uniform among rats while larger variations were observed for human samples.     

Recent Developments to Mitigate Selenium Deficiency in Agricultural Eco-Systems

Under changing climate, trace elements like selenium (Se) have emerged as vital constituent of agro-ecosystems enabling crop plants to off-set the adverse effects of suboptimal growth conditions. The available form of selenium is important for boosting its bioavailability to crop plants having varied agro-botanical traits and root architectural systems. As compared to selenite, the selenate has a weaker soil bonding, higher absorption in the soil solution which results in a comparatively absorption by plant roots. Various factors including dry climate, high pH, optimal ambient air temperature, less accumulation of water, and low concentration of organic matter in the soil tend to boost the selenate ratio in the soil. The use of selenium pelleted seeds has emerged as an interesting and viable alternative to alleviate selenium deficiency in agricultural eco-systems. Similarly, the co-inoculation of a mixture of Selenobacteria and Arbuscular mycorrhizal fungi represents an evolving promising strategy for the bio-fortification of wheat plants to produce selenium-rich flour to supplement human dietary needs. Furthermore, in-depth research is required to assure the effectiveness of biological fertilization procedures in field conditions as well as to explore and increase our understanding pertaining to the underlying main mechanisms and channels of selenium absorption in plants. The focus of this review is to synthesize the recent developments on Se dynamics in soil-plant systems and emerging promising strategies to optimize its levels for crop plants. Recent developments regarding the use of micro-organisms as a biotechnological mean to enhance plant nutrition and crop quality have been objectively elaborated. The study becomes even more pertinent for arid and semi-arid agro-ecosystems owing to the potential role of selenium in providing stress tolerance to crop plants. Moreover, this review synthesizes and summarizes the recent developments on climate change and bioavailability, and the protective role of selenium in crop plants.