Induction of thrombospondin-1 by all-trans retinoic acid modulates growth and differentiation of HL-60 myeloid leukemia cells

Thrombospondin-1 (TSP), a multifunctional extracellular matrix protein, modulates human hematopoietic stem cell adherence and thus may play a role in blood cell proliferation and/or differentiation. The expression of TSP was studied in the human myeloid leukemia cell line, HL-60, upon differentiation into monocytes by phorbol-13-monoacetate (PMA) or into granulocytes by all-trans retinoic acid (RA). HL-60 cells cultured under serum-free conditions constitutively secreted low amounts of TSP into the cultured medium, approximately 13 ng/10(6) cells/24 h. PMA used at 4 x 10(-8) M did not significantly modulate TSP secretion over a 24 h period. In contrast, RA at 10(-7) M induced a 5- to 10-fold increase in TSP secreted by HL-60 cells during their differentiation into granulocytes over a 5 day period. The role of secreted TSP in RA-dependent cessation of growth and differentiation was examined using blocking anti-TSP antibodies. In the presence of the polyclonal anti-TSP antibody R5 (25 microg/ml), growth of RA-treated HL-60 cells was maintained at control levels for up to 3 days and a concomitant delay in granulocytic differentiation was observed. Moreover, the addition of soluble TSP (0.5-5 microg/ml) to untreated HL-60 cells decreased their growth and promoted their differentiation in a dose-dependent manner. Using a neutralizing antibody to transforming growth factor beta (TGF-beta) or purified TGF-beta1 we further demonstrated that the effects of TSP were not mediated through activation of latent TGF-beta. These studies indicate that TSP decreases the proliferation and promotes the differentiation of HL-60 cells.     

Effect of the dehairing dromedary hair process on yield,fibre diameter,fibre length and fibre tenacity

In raw materials of dromedary hair, there are two distinct fibre populations: the fine one is of textile relevance and the coarse one is rather worthless and must be as a rule separated prior to spinning and subsequent processing. The paper reports an investigation into the effects of fibre passage sequence throughout the Shirley Analyser on the efficiency, the mean fibre diameter and the mean fibre length of the dehairing dromedary hair. Also, it presents the effect of dehairing dromedary hair process on the yield samples.

The results show that the most important effect on percentage yield, mean fibre diameter and mean fibre length is caused by the first passage throughout the Shirley Analyser. Following these experiments, we determined an optimal number of passages which is 4. So, the paper discusses the effect of opening operation for dromedary fleece before dehairing on the percentage yield and efficiency of dehairing.     

Entropy generation and mechanical efficiency in laminar peristaltic flow through an elliptical duct

Heat transfer analysis coupled with peristaltic transport is important in many real-world application areas varying from microchannels to spacecrafts. Power production, chemical, and food industries, electronics, and environmental engineering are some examples of applications. In thermal devices, the overall performance of a heat exchanger depends on heat exchanger efficiency and entropy generation. The main purpose of this paper is to study a mathematical model coupling the peristaltic pumping with the heat transfer phenomenon for an incompressible Newtonian fluid in an elliptical tube. The Navier–Stokes and energy equations have been analytically solved for long wavelength, small Reynolds, and small Peclet numbers approximations. Exact expressions of velocity profile and temperature distribution have been found in the wave frame analysis. The impacts of pertinent parameters on the physical quantities of the problem have been analyzed with the help of graphs. We concluded that the geometrical parameters (occlusion, aspect ratio) enhance the pressure rise and the mechanical efficiency. It should be noted that the best way for minimizing entropy generation is decreasing occlusion, aspect ratio, flow rate, or Brinkman number.     

A case-control study on the association of idiopathic recurrent pregnancy loss with autoantibodies against beta2-glycoprotein I and annexin V

Whereas antiphospholipid antibodies (aPL) are associated with thrombotic events and recurrent spontaneous abortion (RSA), the contribution of anti-beta2 glycoprotein 1 (beta2GP1) and anti-annexin V antibodies as risk factors for RSA remain poorly understood. We investigated anti-beta2-GPI and anti-annexin V IgM and IgG antibodies as potential risk factors for RSA in 200 women with more than three consecutive idiopathic RSA, and 200 age-matched, healthy, parous women. Pearson's chi squared test analysis showed that while anti-beta2-GPI IgG (P = 0.416) and IgM (P = 0.72) were comparable between patients and controls, elevated anti-annexin V IgG (P = 0.006), but not IgM (P = 0.084), was more pronounced in patients. Higher frequencies of elevated IgG-only (P = 0.005), but not IgM-only (P = 1.000; OR = 6.66), anti-annexin V antibodies were noted among patients. Multinomial regression analysis showed that body-mass index (overweight and obesity; P = 0.008), education status (P < 0.001) and anti-beta2-GPI IgM (P = 0.033), but not IgG (P = 0.723), were associated with early abortion, while anti-beta2-GPI IgG (P = 0.030) and anti-annexin V IgG (P = 0.004) were associated with late RSA. For combined early-late RSA, the only variable selected was education status (P < 0.001), and neither anti-annexin V nor anti-beta2-GPI IgM and IgG was associated with early-late RSA. Accordingly, anti-annexin V and anti-beta2-GPI should be regarded as independent risk markers of RSA.     

Estimation of synchronous machine parameters by standstill tests

In this paper we present the results of a time-domain identification procedure to estimate the linear parameters of a salient-pole synchronous machine at standstill.A new approach is proposed for the estimation of synchronous machine coupled to DC-chopper and Pseudo Random Binary Sequences excitations; using data recorded during steady-state operation of the chopper-machine unit. This procedure consists of defining and conducting the standstill tests, identifying the model structure, estimating the corresponding parameters, and validating the resulting model. The signals used for identification are the different excitation voltages at standstill and the flowing current in different windings. We estimate the parameters of operational impedances, or in other terms, the reactances and the time constants.The results are presented from tests on a synchronous machine of 3 kVA/220 V/1500 rpm.     

Antioxidant,lipase and ACE-inhibitory properties of camel lactoferrin and its enzymatic hydrolysates

The antioxidant and the lipase and the angiotensin-converting enzyme (ACE) inhibitory properties of camel lactoferrin and its hydrolysates elaborated with four proteolytic enzymes (trypsin, α-chymotrypsin, pancreatin and papain) were assessed. Lactoferrin was purified from camel colostrum using cation exchange chromatography. Camel lactoferrin hydrolysates showed different degrees of hydrolysis, reverse phase-HPLC profiles and molecular weight distributions, reflecting heterogeneity in terms of polarity and molecular weight of the generated peptides. Camel lactoferrin hydrolysates exhibited higher antioxidant, lipase and ACE inhibitory activities than native lactoferrin. Pancreatin-generated hydrolysates showed the highest lipase inhibitory activity (48.1%), while papain-generated hydrolysates presented the greatest ACE inhibitory activity (89.14%).