Adenosine receptors expression is elevated in leukocytes of gestational diabetes mellitus (GDM) subjects — a preliminary study

Introduction: Adenosine receptors (ARs), belonging to the G-protein-coupled receptors (GPCRs), are present in the majority of human cells and tissues. Depending on their biochemical and pharmacologic properties, four subtypes of ARs (i.e. A1, A2A, A2B, and A3) have been distinguished. Currently, these receptors are attractive molecular targets for pharmacological interventions in various diseases, including diabetes. The literature published to date has shown an altered expression of ARs in several types of cells under diabetic conditions. However, there has been no publication devoted to the investigation of ARs expression in leukocytes of subjects with gestational diabetes mellitus (GDM). Therefore, this study was aimed to determine the expression level of AR subtypes in leukocytes of GDM patients and its relationship to anthropometric and biochemical parameters. Material and methods: Gene expression of four AR subtypes in leukocytes of both healthy (n = 34) and GDM (n = 67) subjects in the third trimester of pregnancy (from 24 to 33 weeks) was investigated. Multiple regression analyses were used to assess the association between the expression level of ARs and both anthropometric and biochemical parameters. Results: Statistically significant (p < 0.05) higher levels of A2A and A2B mRNAs were observed in leukocytes of the GDM subjects compared to the control group. There was a positive correlation of A2B mRNA level with glucose concentration at 120 min of oral glucose tolerance test (OGTT) (r = 0.24, p = 0.041). Conclusions: Overexpression of A2BAR in leukocytes of the GDM subjects and, additionally, the existence of a relationship between its elevated expression level in these cells and abnormal values of glucose concentration at 120 min of OGTT for GDM, suggest that this subtype might be involved in the pathogenesis of GDM. (Pol J Endocrinol 2012; 63 (2): 110&#8211;114)Wstęp: Receptory adenozynowe (ARs) należą do błonowych receptorów sprzężonych z białkami G, które są obecne w większości ludzkich komórek i tkanek. Na podstawie ich biochemicznych i farmakologicznych właściwości wyróżniono cztery podtypy ARs (tj. A1, A2A, A2B, A3). Obecnie receptory te stanowią atrakcyjne molekularne cele dla farmakologicznych interwencji w różnych chorobach, w tym cukrzycy. W dostępnym piśmiennictwie istnieją dane wskazujące, że poziom ekspresji receptorów może ulegać zmianom w niektórych typach komórek podczas cukrzycy, natomiast nie ma publikacji dotyczących badania ekspresji ARs w leukocytach pacjentek z cukrzycą ciążową (GDM). Dlatego celem pracy było określenie poziomu ekspresji czterech podtypów ARs w leukocytach kobiet z GDN i ich korelacja z wybranymi parametrami antropometrycznymi i metabolicznymi. Materiał i metody: Poziom ekspresji czterech podtypów ARs badano w leukocytach kobiet w ciąży, zarówno zdrowych (n = 34; grupa kontrolna), jak i ze zdiagnozowaną GDM (n = 67). Poziomy ekspresji korelowano z oznaczonymi parametrami antropometrycznymi i biochemicznymi. Wyniki: W grupie GDM zaobserwowano istotny statystycznie (p < 0,05) wzrost poziomu mRNA receptorów A2A and A2B w porównaniu z grupą kontrolną. Zaznaczyła się również dodatnia korelacja między poziomem ekspresji receptora A2B a stężeniem glukozy w 2. godzinie testu doustnego obciążenia 75 g glukozy (r = 0,24; p = 0,041). Wnioski: Zarówno istotnie podwyższony poziom ekspresji receptora A2B w leukocytach kobiet z GDM, jak i istnienie dodatniej korelacji między poziomem ekspresji receptora A2B w tych komórkach a stężeniem glukozy wskazują na jego potencjalny udział w patogenezie GDM. (Endokrynol Pol 2012; 63 (2): 110&#8211;114

The tribology of the car: Research methodology and evaluation criteria

From a position of structural and power theory of friction and wear, it is possible to apply the method of Contact Electrical Resistance (CER) for a complex research of the processes in a-zone of frictional contact. The purpose of this paper is to present a construction of friction node and drive mechanism of friction machine. As a result of the reported study the regularities of changes the CER and tribomechanical indices for non-metal friction couples in dependence on loading parameters and lubricating media were received. Also, the method of determination the range and level of normal wear and critical points of transmission to damage in accordance with kinetics of wear changes is proposed. The interrelation between geometrical, physical and mechanical properties, processes of formation, transformation and destruction of secondary structures, tribotechnical indices and CER in dependence on operation regimes of friction couples

Reactivity of 2-formylphenylboronic acid toward secondary aromatic amines in amination–reduction reactions

The synthesis of 2-(arylaminomethyl)phenylboronic acid via an amination–reduction reaction has been investigated within a model system comprising 2-formylphenylboronic acid and N-ethylaniline. Adoption of the appropriate reaction conditions influences the reactivity of 2-formylphenylboronic acid, enabling efficient synthesis of so-far unobtainable 2-(arylaminomethyl)phenylboronic compounds. The first crystal structure of the aromatic amine derivative has been determined and described

Electromagnetically assisted densification of copper-sheathed in situ MgB2/Cu wires

peer-reviewedThis paper summarizes recent methods of improving critical current density of in situ Cu-sheathed MgB2 wires. These methods include using optimum heat treatment schedule, adding copper powder to the wire core and electromagnetic densification of wire core. The large part of work reported here focuses on the latter method applied to the relatively low-density MgB2/Cu wire core. The packing density of unreacted, monofilament wire core was increased by 8 % with oscillating magnetic pressure, reaching a peak value above 700 MPa as calculated by finite element modelling of the forming process. The higher density of the MgB2 core combined with copper powder addition resulted in a critical current density increase of more than fivefold in comparison to purely stoichiometric and cold-drawn-only wire.PUBLISHEDpeer-reviewe

The Araucaria Project. An improved distance to the Sculptor spiral galaxy NGC 300 from its Cepheid variables

In a previous paper, we reported on the discovery of more than a hundred new Cepheid variables in the Sculptor Group spiral NGC 300 from wide-field images taken in the B and V photometric bands at ESO/La Silla. In this paper, we present additional VI data, derive improved periods and mean magnitudes for the variables, and construct period-luminosity relations in the V, I and the reddening-independent (V-I) Wesenheit bands using 58 Cepheid variables with periods between 11 and 90 days. We obtain tightly defined relations, and by fitting the slopes determined for the LMC Cepheids by the OGLE II Project we obtain reddening-corrected distances to the galaxy in all bands. We adopt as our best value the distance derived from the reddening-free Wesenheit magnitudes, which is 26.43 $\pm$ 0.04 (random) $\pm$ 0.05 (systematic) mag. We argue that our current distance result for NGC 300 is the most accurate which has so far been obtained using Cepheid variables, and that it is largely free from systematic effects due to metallicity, blending, and sample selection. It agrees very well with the recent distance determination from the tip of the red giant branch method obtained from HST data by Butler et al. (2004), and it is consistent with the Cepheid distance to NGC 300 which was derived by Freedman et al. (2001) from CCD photometry of a smaller sample of stars.Comment: Latex, Astronomical Journal in pres

The Araucaria Project. The Distance to the Local Group Galaxy NGC 6822 from Cepheid Variables discovered in a Wide-Field Imaging Survey

We have obtained mosaic images of NGC 6822 in V and I bands on 77 nights. From these data, we have conducted an extensive search for Cepheid variables over the entire field of the galaxy, and we have found 116 such variables with periods ranging from 1.7 to 124 days. We used the long-period ($>$ 5.6 days) Cepheids to establish the period-luminosity relations in V, I and in the reddening-independent Wesenheit index, which are all very tightly defined. Fitting the OGLE LMC slopes in the various bands to our data, we have derived distance values for NGC 6822 in V, I and ${\rm W}_{\rm I}$ which agree very well among themselves. Our adopted best distance value from the reddening-free Wesenheit index is 23.34 $\pm$ 0.04 (statistical) $\pm$ 0.05 (systematic) mag. This value agrees within the combined 1 sigma uncertainties with a previous distance value derived for NGC 6822 by McAlary et al. from near-IR photometry of 9 Cepheids, but our new value is significantly more accurate. We compare the slopes of the Cepheid PL relation in V and I as determined in the five best-observed nearby galaxies, which span a metallicity range from -1.0 to -0.3 dex, and find the data consistent with no metallicity dependence of the PL relation slope in this range. Comparing the magnitudes of 10-day Cepheids with the I-band magnitudes of the TRGB in the same set of galaxies, there is no evidence either for a significant variation of the period-luminosity zero points in V and I. The available data limit such a zero point variation to less than 0.03 mag, in the considered low-metallicity regime.Comment: Latex, Astronomical Journal accepte

The Araucaria Project. The Distance to the Local Group Galaxy WLM from Cepheid Variables discovered in a Wide-Field Imaging Survey

We have conducted an extensive wide-field imaging survey for Cepheid variables in the Local Group irregular galaxy WLM. From data obtained on 101 nights, we have discovered 60 Cepheids which include 14 of the 15 Cepheid variables previously detected by Sandage and Carlson. Down to a period of 3 days, our Cepheid survey in WLM should be practically complete. Importantly, we have found for the first time a long-period Cepheid (P=54.2 days) in this galaxy, alleviating the puzzle that WLM with its many blue, massive stars does not contain Cepheids with periods longer than about 10 days. Our data define tight period-luminosity relations in V, I and the reddening-free Wesenheit magnitude ${\rm W}_{\rm I}$ which are all extremely well fit by the corresponding slopes of the LMC Cepheid PL relation, suggesting no change of the PL relation slope down to a Cepheid metal abundance of about -1.0 dex, in agreement with other recent studies. We derive a true distance modulus to WLM of 25.144 $\pm$0.03 (r) $\pm$0.07 (s) mag from our data, in good agreement with the earlier 24.92 $\pm$ 0.21 mag determination of Lee, Freedman and Madore (1993a) from Cepheid variables. The quoted value of the systematic uncertainty does not include the contribution from the LMC distance which we have assumed to be 18.50 mag, as in the previous papers in our project.Comment: AJ accepte

The Araucaria Project. A Wide-Field Photometric Survey for Cepheid Variables in NGC 3109

We have obtained mosaic images of NGC 3109 in the V and I bands on 74 nights, spanning approximately one year. From these data, we have conducted an extensive search for Cepheid variables over the entire field of the galaxy, resulting in the discovery of 113 variables with periods ranging from 3.4 to 31.4 days. In this sample, 76 Cepheids, including many long-period variables, were not known before. For the previously known 45 Cepheids in this galaxy, our data proved that reported periods were wrong for 14 objects; for nearly all other previously known Cepheid variables we were able to significantly improve on the periods. We construct period-luminosity relations from our data and obtain reddening-corrected distance moduli of 25.72 $\pm$ 0.05 mag in V, and 25.66 $\pm$ 0.04 mag in I. The distance modulus derived form the reddening-independent V-I Wesenheit index turns out to be significantly shorter (25.54 $\pm$ 0.05 mag), which indicates that in addition to the foreground extinction of E(B-V) = 0.05 mag, there is an intrinsic to NGC 3109 redening of about 0.05 mag. Our distance obtained based on the reddening-free Wesenheit magnitudes is consistent with earlier distance determinations of NGC 3109 from Cepheids, and the tip of the red giant branch. We will improve on our distance and extinction determination combining our optical data with the follow-up near-infrared observations of a subsample of NGC 3109 Cepheids.Comment: accepted to be published in the Ap

The Araucaria Project. The Distance to the Sculptor Group Galaxy NGC 55 from a Newly Discovered Abundant Cepheid Population

We have detected, for the first time, Cepheid variables in the Sculptor Group SB(s)m galaxy NGC 55. From wide-field images obtained in the optical V and I bands during 77 nights in 2002-2003, we have found 143 Cepheids with periods ranging from 5.6 to 175.9 days. 133 of these objects have periods longer than 10 days, making NGC 55 to-date the galaxy with the largest known number of long-period Cepheids in the Sculptor Group. We construct period-luminosity relations from our data and obtain distance moduli corrected for the small foreground reddening to NGC 55 of 26.79 $\pm$ 0.04 mag (internal error) in V, 26.66 $\pm$ 0.03 mag in I and 26.40 $\pm$ 0.05 mag in the reddening-independent V-I Wesenheit index. The trend of increasing distance moduli with shorter wavelength hints at the existence of significant reddening intrinsic to NGC 55 which affects the measured Cepheid magnitudes. From our data, we determine the intrinsic mean reddening of the Cepheids in NGC 55 as E(B-V) = 0.102 mag which brings the distance determinations from the different bands into excellent agreement. Our best distance estimate for NGC 55 from the present optical Cepheid photometry is 26.40 mag $\pm$ 0.05 mag (internal error) $\pm$ 0.09 mag (systematic error). This value is tied to an assumed LMC distance of 18.50 mag. Our quoted systematic error of the present NGC 55 Cepheid distance does not take into account the current uncertainty on the distance of the fiducial LMC galaxy itself. Within the small respective uncertainties, the Sculptor Group galaxies NGC 55 and NGC 300 are at the same distance of 1.9 Mpc, strengthening the case for a physical association of these galaxiesComment: Astronomical Journal in press (December issue