Effects of Leukaemia Inhibitory Factor Receptor on the Early Stage of Osteogenic Differentiation of Human Bone Marrow Mesenchymal Cells.

Leukaemia inhibitory factor (LIF) has a wide variety of biological activities. While recent studies have focused on the role of LIF in osteoblast differentiation, the exact role of LIFR during the early stage of osteogenic differentiation remains unclear. We observed that LIFR expression gradually decreased during the early stage of osteogenic differentiation of hMSCs. To evaluate how LIFR regulates osteogenic differentiation in greater depth, we transfected hMSCs with LIFR overexpression and siRNA lentiviral plasmids. Cells were divided into four groups: a negative overexpression control group, a LIFR overexpression group, a negative siRNA control group, and a LIFR siRNA group. On different days (0, 3, and 6) of the osteogenic differentiation of hMSCs, alkaline phosphatase (ALP) activity was assayed with an ALP staining and activity assay kit. Cells were harvested to assess the mRNA and protein expression of LIF, LIFR, and osteogenesis-related factors (ALP; RUNX2; osteonectin) by qRT-PCR and western blot analyses, respectively. In addition, culture supernatants were tested for the LIF content by ELISA. Our results showed that overexpression of LIFR significantly suppressed the osteoblast differentiation of hMSCs. In contrast, LIFR siRNA markedly improved this osteoblast differentiation as determined by ALP staining and activity measurements. Moreover, RUNX2, ALP, and ONN expression was also significantly changed by altering LIFR expression. We further analysed the expression of LIF and LIFR, revealing consistent LIF and LIFR trends during the osteogenic differentiation of hMSCs. Together, these results suggested that LIFR may be a novel negative regulator during the early stage of hMSC osteogenic differentiation.

Treatment of synthetic kraft evaporator condensate using thermophilic and mesophilic membrane aerated biofilm reactors.

A comparative study on the treatment of synthetic kraft evaporator condensate was conducted using thermophilic (55 degrees C) and mesophilic (30 degrees C) membrane aerated biofilm reactors (MABRs) and sequencing batch reactors (SBRs) for 8 months. Under tested conditions, a chemical oxygen demand (COD) removal efficiency of 80-95% was achieved with both thermophilic and mesophilic MABRs and SBRs. The COD removal efficiency of thermophilic MABR (80-90%) was slightly lower than that of the mesophilic MABR (85-95%) and the thermophilic SBR (90-95%). A significant amount (13-37%) of COD was stripped by conventional aeration in the SBRs, while stripping in MABRs was negligible. Simultaneous COD removal and denitrification were observed in the mesophilic MABR, while the thermophilic MABR contributed mainly for COD removal. Nitrification was not significant in both the thermophilic and mesophilic MABRs. The results suggest that treatment of kraft evaporator condensate is feasible with the use of both thermophilic and mesophilic MABRs in terms of COD removal with the advantages of negligible stripping.

Quantitative morphological study of Langerhans cells by computerized image analysis.

ATPase-stained normal and topical nitrogen mustard treated Langerhans cells (LC) in guinea pig epidermis were studied quantitatively and morphologically by computerized image analysis. Significant correlation and linear regression were found between the perimeter and square root of its area for both cytoplasm and nucleus; a theoretical basis was thus given for morphological identification of LC. The directly measured and derived geometric parameters indicated not only substantial alteration of cytoplasm morphology of post-treated LC such as cytoplasmatosis and dendrites reduction but also a potential change of nuclear size and functional status. We conclude that quantitative morphological analysis is an objective, precise and practical method for LC research.

Chemotaxis of polymorphonuclear leukocytes towards LTB4 in patients with psoriasis in vitro.

The random migration and chemotaxis of polymorphonuclear leukocytes (PMN) in agarose were studied in 21 patients with psoriasis and 10 healthy controls. Different concentrations of LTB4 were used as chemoattractants. The random migration and chemotaxis towards lower concentrations of LTB4 were enhanced and that towards higher concentrations of LTB4 reduced in psoriasis. The differences of body involvement, sex, and family history of psoriasis had no influence on PMN migration.

Effects of antipsoriatic drugs on biosynthesis of platelet activating factor by human keratinocytes.

Human keratinocytes in primary culture stimulated by Ca2+ ionophore A23187(Io) could synthesize and release a material which might aggregate aspirin-treated washed rabbit platelets and was identified as platelet activating factor (PAF) by four methods. Io stimulated the production of PAF by keratinocytes in a time- and dose-dependent manner. The PAF precursors, i.e., AAGPC and Lyso-PAF, were detected in keratinocytes. Nitrogen mustard and dexamethasone could time- and dose-dependently inhibit PAF biosynthesis from Io to induce human keratinocytes in culture. The IC50 of nitrogen mustard and dexamethasone were 6.34 x 10(-9) M and 1.005 x 10(-8) M respectively. The results showed that the synthesis and release of PAF by normal human keratinocytes may be accounted for the development of cutaneous inflammation and the pathogenesis of some skin disorders and application of drugs that inhibit PAF synthesis may be a new and effective approach to the management of some inflammatory skin diseases such as psoriasis.

[Effect of BN52021 on platelet activating factor induced aggregation of psoriatic polymorphonuclear neutrophils].

We investigated the aggregation of PMN from 20 psoriasis patients (PP) and 12 health persons (HP) to PAF and the effect of PAF antagonist BN 52021 on the aggregation. PAF induced a dose dependent aggregative response of polymorphonuclear neutrophils (PMN) from PP and HP. The aggregative responses of PMN from PP to lower concentrations of PAF were increased (P < 0.05) and to higher concentrations of PAF were not different to that of PMN from HP. BN 52021 could time- and dose-dependently inhibit the aggregation of PMN from PP and HP to PAF, and their IC50 was 1.3 x 10(-6) mol and 1.2 x 10(-6) mol respectively. It is suggested that PAF and PMN play an important pathophysiological role in the development of psoriasis, and application of PAF antagonists may be a new and effective approach to the management of psoriasis.