Both CD34+38+ and CD34+38- cells home specifically to the bone marrow of NOD/LtSZ scid/scid mice but show different kinetics in expansion

Human hemopoietic stem cells (HSC) have been shown to engraft, differentiate, and proliferate in the hemopoietic tissues of sublethally irradiated NOD/LtSZ scid/scid (NOD/SCID) mice. We used this model to study homing, survival, and expansion of human HSC populations from different sources or phenotype. We observed that CD34+ cells homed specifically to bone marrow (BM) and spleen, but by 3 days after injection, survived only in the BM. These BM-homed CD34+ cells proliferated intensively and gave rise to a 12-fold, 5.5-fold, and 4-fold expansion in 3 days for umbilical cord blood, adult mobilized peripheral blood, and adult BM-derived cells, respectively. By injection of purified subpopulations, it was demonstrated that both CD34+38+ and CD34+38- umbilical cord blood HSC homed to the BM and expanded. Importantly, kinetics of expansion were different: CD34+38+ cells started to increase in cell number from day 3 onwards, and by 4 wk after injection, virtually all CD34+ cells had disappeared. In contrast, CD34+38- cells remained quiescent during the first week and started to expand intensively from the third week on. In this paper, we have shown that homing, survival, and expansion of stem cells are three independent phenomena important in the early phase of BM engraftment and that kinetics of engraftment differ between CD34+38+ and CD34+38- cells.     

Unilateral longitudinal radial ray deficiency of the hand and metacarpal 4-5 synostosis

We report 3 non related patients with severe hypoplasia/aplasia of the thumb with an ipsilateral synostosis of the fourth and fifth metacarpals. A review of few reports on this unusual association is presented and the possible pathogenetic mechanism is discussed.     

Xestospongin C is an equally potent inhibitor of the inositol 1,4,5-trisphosphate receptor and the endoplasmic-reticulum Ca(2+) pumps

Xestospongins, a group of macrocyclic bis-1-oxaquinolizidines isolated from the Australian sponge, Xestospongia species, are potent blockers of the inositol 1,4,5-trisphosphate (IP(3))-induced Ca2+ release in bi-directional Ca2+-flux conditions. We have now studied the effects of xestospongin C on the (45)Ca2+ uptake and the uni-directional (45)Ca2+ efflux in permeabilized A7r5 smooth-muscle cells. Xestospongin C not only inhibits the IP(3)-induced Ca2+ release, but is also an equally potent blocker of the endoplasmic-reticulum Ca2+ pump, while it has no effect on the passive Ca2+ leak. The inhibition of the IP(3) receptor did not depend on the IP(3), Ca2+ or ATP concentration. Xestospongin C can, therefore, not be considered as a selective blocker of IP(3) receptors.     

Biological activity and conformational analysis of C20 and C14 epimers of CD-ring modified trans-decalin 1alpha,25-dihydroxyvitamin D analogs

In the context of our ongoing study of vitamin D structure-function relationships and in an attempt to obtain a better dissociation of their prodifferentiating (HL-60) and/or antiproliferative (MCF-7) activities and their calcemic activity, further 20-epi and 14-epi modifications were made to three trans-decalin CD-ring analogs of 1,25-dihydroxyvitamin D(3), the hormonally active metabolite of vitamin D(3), possessing a natural 20R side chain and featuring additional structural modifications in the seco-B-ring and in the A-ring. Following a previously observed trend and in agreement with the conformational analysis results, all three 20-epi derivatives show substantially lower biological activities, opposite to what is usually observed for analogs having the natural CD-ring. The 14-epi modification (cis-decalins) has little effect on the biological activity of the ynediene type and the saturated derivative, but results in an approximate 10-fold reduction in activity of the previtamin derivative. No better dissociation of the prodifferentiating and/or antiproliferative activities and the calcemic activity was achieved.     

Antigens up the nose: identification of putative biomarkers for nasal tolerance induction functional studies combined with proteomics

Intranasal autoantigen delivery is the most effective means of inducing mucosal tolerance and suppression of autoimmune disease. In an effort to identify markers of the "tolerant state", we employed proteomics technology at the level of the cervical lymph node. The analysis revealed that nasal antigen administration (without adiuvant) led to modulation of various proteins among which the most prominent were haptoglobin, nonintegrin 67 kDa laminin receptor, and MRP8. The immunoregulatory haptoglobin may qualify as (bio)marker for effective immunotherapy.     

Chemoenzymatic synthesis and biological evaluation of C-3 carbamate analogues of 1alpha,25-dihydroxyvitamin D3

The synthesis of new analogues of 1alpha,25-dihydroxyvitamin D3 containing a carbamate function at the A-ring fragment has been described using the cross-coupling approach. The carbamate group was selectively introduced at the C-3 position by regioselective enzymatic alkoxycarbonylation of A-ring enyne 3 and subsequent treatment with ammonia, amines, amino alcohols, and amino acids. Biological studies to evaluate the potency of all five of these carbamate analogues were performed and demonstrated very low binding affinity for the vitamin D receptor compared with 1alpha,25-dihydroxyvitamin D3. Moreover, all the carbamate analogues were less active than 1alpha,25-dihydroxyvitamin D3 in inhibiting cell proliferation or stimulating cell differentiation. Of all the five analogues, the 3-O-carbamoyl-1alpha,25-(OH)2-D3 analogue 10a was the most potent one in vitro. However, all investigated carbamate analogues demonstrated lower calcemic effects in vivo than the parent compound.     

Increased acute inflammation, leukotriene B4-induced chemotaxis, and signaling in mice deficient for G protein-coupled receptor kinase 6

Directed migration of polymorphonuclear neutrophils (PMN) is required for adequate host defense against invading organisms and leukotriene B(4) (LTB(4)) is one of the most potent PMN chemoattractants. LTB(4) exerts its action via binding to BLT1, a G protein-coupled receptor. G protein-coupled receptors are phosphorylated by G protein-coupled receptor kinases (GRK) in an agonist-dependent manner, resulting in receptor desensitization. Recently, it has been shown that the human BLT1 is a substrate for GRK6. To investigate the physiological importance of GRK6 for inflammation and LTB(4) signaling in PMN, we used GRK6-deficient mice. The acute inflammatory response (ear swelling and influx of PMN into the ear) after topical application of arachidonic acid was significantly increased in GRK6(-/-) mice. In vitro, GRK6(-/-) PMN showed increased chemokinetic and chemotactic responses to LTB(4). GRK6(-/-) PMN respond to LTB(4) with a prolonged increase in intracellular calcium and prolonged actin polymerization, suggesting impaired LTB(4) receptor desensitization in the absence of GRK6. However, pre-exposure to LTB(4) renders both GRK6(-/-) as well as wild-type PMN refractory to restimulation with LTB(4), indicating that the presence of GRK6 is not required for this process to occur. In conclusion, GRK6 deficiency leads to prolonged BLT1 signaling and increased neutrophil migration.     

ABA plays a central role in mediating the regulatory effects of nitrate on root branching in Arabidopsis

The formation of lateral roots (LR) is a major post-embryonic developmental event in plants. In Arabidopsis thaliana, LR development is inhibited by high concentrations of NO3(-). Here we present strong evidence that ABA plays an important role in mediating the effects of NO3(-) on LR formation. Firstly, the inhibitory effect of NO3(-) is significantly reduced in three ABA insensitive mutants, abi4-1, abi4-2 and abi5-1, but not in abi1-1, abi2-1 and abi3-1. Secondly, inhibition by NO3(-) is significantly reduced, but not completely abolished, in four ABA synthesis mutants, aba1-1, aba2-3, aba2-4 and aba3-2. These results indicate that there are two regulatory pathways mediating the inhibitory effects of NO3(-) in A. thaliana roots. One pathway is ABA-dependent and involves ABI4 and ABI5, whereas the second pathway is ABA-independent. In addition, ABA also plays a role in mediating the stimulation of LR elongation by local NO3(-) applications.     

Optimization of the chiral separation of some 2-arylpropionic acids on an avidin column by modeling a combined response

The enantiomeric separation of some nonsteroidal antiinflammatory drugs was investigated on an avidin column. An experimental design approach (central composite design) was used to evaluate the effects of three method parameters (pH, concentration of organic modifier, and buffer concentration) on the analysis time and the resolution, as well as to model these responses. This revealed that the organic modifier concentration and sometimes the pH are significant parameters to control because of their influence on both analysis time and resolution. Furthermore, the central composite design results were combined in a multicriteria decision-making approach in order to obtain a set of optimal experimental conditions leading to the most desirable compromise between resolution and analysis time.