Inhibition of TGF-β Signaling Promotes Human Pancreatic β-Cell Replication.

Diabetes is associated with loss of functional pancreatic β-cells, and restoration of β-cells is a major goal for regenerative therapies. Endogenous regeneration of β-cells via β-cell replication has the potential to restore cellular mass; however, pharmacological agents that promote regeneration or expansion of endogenous β-cells have been elusive. The regenerative capacity of β-cells declines rapidly with age, due to accumulation of p16(INK4a), resulting in limited capacity for adult endocrine pancreas regeneration. Here, we show that transforming growth factor-β (TGF-β) signaling via Smad3 integrates with the trithorax complex to activate and maintain Ink4a expression to prevent β-cell replication. Importantly, inhibition of TGF-β signaling can result in repression of the Ink4a/Arf locus, resulting in increased β-cell replication in adult mice. Furthermore, small molecule inhibitors of the TGF-β pathway promote β-cell replication in human islets transplanted into NOD-scid IL-2Rg(null) mice. These data reveal a novel role for TGF-β signaling in the regulation of the Ink4a/Arf locus and highlight the potential of using small molecule inhibitors of TGF-β signaling to promote human β-cell replication

Space Complexity of Perfect Matching in Bounded Genus Bipartite Graphs

We investigate the space complexity of certain perfect matching problems over bipartite graphs embedded on surfaces of constant genus (orientable or non-orientable). We show that the problems of deciding whether such graphs have (1) a perfect matching or not and (2) a unique perfect matching or not, are in the logspace complexity class \SPL. Since \SPL\ is contained in the logspace counting classes \oplus\L (in fact in \modk\ for all $k\geq 2$), \CeqL, and \PL, our upper bound places the above-mentioned matching problems in these counting classes as well. We also show that the search version, computing a perfect matching, for this class of graphs is in \FL^{\SPL}. Our results extend the same upper bounds for these problems over bipartite planar graphs known earlier. As our main technical result, we design a logspace computable and polynomially bounded weight function which isolates a minimum weight perfect matching in bipartite graphs embedded on surfaces of constant genus. We use results from algebraic topology for proving the correctness of the weight function.Comment: 23 pages, 13 figure

Study of semen parameters in male partners among infertile couples

Background: The Semen analysis provides valuable information about the etiology and fertility potential of an infertile male. The study was conducted to determine the abnormalities in semen parameters of male partners of infertile couples and to find out contribution of male factors.Methods: The descriptive study with cross sectional design was conducted in the department of Pathology at MIMSR medical college, Latur, Maharashtra, India, between January 2013 to December 2014. A total of 220 cases were analyzed during this period. Semen analysis was performed according to the methods and the standards defined by World Health Organisation (WHO) 5th edition 2010.Results: Out of 220 male partners of infertile couples 96 (43.6%) men had abnormal semen parameters. The male factor was responsible in 43.6% of cases. Asthenozoospermia constitutes maximum of 19.9%, followed by Oligozoospermia in 18.6%, Azoospermia in 10.9%, Oligoasthenoteratozoospermia in 7.3% and Oligoasthenozoospermia in 6.8% cases. Leucocytospermia was detected in 15.5% cases.Conclusions: Abnormal semen quality remains a significant contribution to overall infertility. Asthenozoospermia is the most common semen abnormality seen

Associated HI absorption in the z=3.4 radio galaxy B2 0902+343 observed with the GMRT

We have made observations of the associated HI absorption of a high redshift radio galaxy 0902+34 at z=3.395 with the Giant Meterwave Radio Telescope in the $323\pm1$ MHz band. We find a narrow absorption line with a flux density of 11.5 mJy at a redshift of 3.397 consistent with that observed by Uson et al. (1991), Briggs et al. (1993) and de Bruyn (1996).A weak broad absorption feature reported by de Bruyn (1996) has not been detected in our observations. We also place an upper limit of 4 mJy (2 $\sigma$) on emission line strength at the position where Uson et al. (1991) claimed to have found a narrow emission line.Comment: To appear in Journal of Astronomy and Astrophysic