Does altered insulin signalling modulate vascular regeneration?

The prevalence of insulin resistant syndromes is rising worldwide. Affected individuals are at increased risk of morbidity and premature mortality, much of which is driven by cardiovascular disease (CVD). Enhancement of vascular regeneration, using pharmacological or cell-based therapies, has been suggested as a strategy to help address these issues. Although many pathophysiological processes associated with insulin resistant syndromes are likely to impair vascular regeneration, the effect of insulin resistance per se is not established. South Asian (SA) ethnicity is associated with increased risk of CVD, and insulin resistance is thought to be a major contributor to this. We compared the angiogenic capacity of late outgrowth endothelial progenitor cells (LEPCs) from young SA men, with those from a matched group white European (WE) men. LEPC have previously been shown to offer potential as an autologous cell therapy in preclinical models of ischaemic CVD. Both groups were well matched, and free of classical cardiovascular risk factors, but the SA group were relatively insulin resistant. SA LEPCs did not augment vascular regeneration in a murine model of limb ischaemia, in contrast with WE LEPC. Akt activity, a critical modulator of angiogenesis, was reduced in SA LEPC, and we were able to rescue SA LEPC dysfunction by enhancing Akt activity. We then established the impact of insulin resistance per se on vascular regeneration, using insulin receptor haploinsufficient mice (IRKO). Indices of angiogenesis were reduced in isolated endothelial cells, aortic ring 5 segments, and ischaemic hind limb muscle. Moreover, this was associated with functional resistance to vascular endothelial growth factor (VEGF), which may have mechanistically contributed to our observations. Together, these data provide insight into how insulin resistance may promote the development of premature CVD, and show that by manipulating key growth factor signalling nodes, we can rescue impaired vascular regeneration. Furthermore, we have established that insulin resistance negatively impacts on the functional response to VEGF, and it will be important to explore the mechanisms underlying this phenomenon in future studies. It is hoped that these findings will help lead to the development of strategies to mitigate the effects of CVD in individuals with insulin resistance

Metastasizing placental site trophoblastic tumor: Immunohistochemical and DNA analysis 2 case reports and a review of the literature

Placental-site trophoblastic tumor (PSTT) is a rare form of gestational trophoblastic neoplasia. The clinical behaviour of PSTT is usually benign, but sometimes it can be highly malignant with late recurrence and metastasis. We describe two cases of PSTT with pulmonary metastasis in patients aged 35 and 29 years respectively. The mitotic rate was elevated to 9 and 13 mitotic figures per 10 high-power fields respectively. Immunohistochemical staining showed a predominance of human placental lactogen (hPL) positive cells when compared with human chorionic gonadotropin (hCG) reactive cells in one case, and a reverse pattern in the other one. DNA measurement in one case showed an aneuploid tumor with a tetraploid DNA peak. The clinical behaviour of PSTT remains unpredictable, and there are no reliable means of predicting clinical outcom

HST/NICMOS observations of the GLIMPSE9 stellar cluster

We present HST/NICMOS photometry, and low-resolution K-band spectra of the GLIMPSE9 stellar cluster. The newly obtained color-magnitude diagram shows a cluster sequence with H-Ks =1 mag, indicating an interstellar extinction Aks=1.6\pm0.2 mag. The spectra of the three brightest stars show deep CO band-heads, which indicate red supergiants with spectral type M1-M2. Two 09-B2 supergiants are also identified, which yield a spectrophotometric distance of 4.2\pm0.4 kpc. Presuming that the population is coeval, we derive an age between 15 and 27 Myr, and a total cluster mass of 1600\pm400 Msun, integrated down to 1 Msun. In the vicinity of GLIMPSE9 are several HII regions and SNRs, all of which (including GLIMPSE 9) are probably associated with a giant molecular cloud (GMC) in the inner galaxy. GLIMPSE9 probably represents one episode of massive star formation in this GMC. We have identified several other candidate stellar clusters of the same complex.Comment: 13 pages, 14 figures. accepted for publication in ApJ. A version with high-resolution figures can be found at the following location ftp://ftp.rssd.esa.int/pub/mmessine/ms.pdf New version with updated reference

Massive stars in the Cl 1813-178 Cluster. An episode of massive star formation in the W33 complex

Young massive (M >10^4 Msun) stellar clusters are a good laboratory to study the evolution of massive stars. Only a dozen of such clusters are known in the Galaxy. Here we report about a new young massive stellar cluster in the Milky Way. Near-infrared medium-resolution spectroscopy with UIST on the UKIRT telescope and NIRSPEC on the Keck telescope, and X-ray observations with the Chandra and XMM satellites, of the Cl 1813-178 cluster confirm a large number of massive stars. We detected 1 red supergiant, 2 Wolf-Rayet stars, 1 candidate luminous blue variable, 2 OIf, and 19 OB stars. Among the latter, twelve are likely supergiants, four giants, and the faintest three dwarf stars. We detected post-main sequence stars with masses between 25 and 100 Msun. A population with age of 4-4.5 Myr and a mass of ~10000 Msun can reproduce such a mixture of massive evolved stars. This massive stellar cluster is the first detection of a cluster in the W33 complex. Six supernova remnants and several other candidate clusters are found in the direction of the same complex.Comment: 11 Figures. Accepted for publication in Ap

Multi-Nation WPT Demonstration Experiments

A project originating with Georgia Institute of Technology is described in which the International Space Station (ISS) serves as an experimental platform for the relay of energy from space to earth. The multi-nation test will feature the transmission of small amounts of solar-generated electric power from the ISS using millimeter waves, for the purposes of collecting atmospheric propagation data and testing technologies for power beaming, aiming, and reception. This initiative represents an early first-step towards installation of a global Space Solar Power Grid emphasizing international collaboration, synergy with the terrestrial energy industry and with retail power beaming markets. The technical paper on which this visualization is based is listed in References below. Advisors: Prof. N. Komerath, Prof. D. Flournoy, Kyle Perkins (Designer) Five-Nation - Broadband from Space Journal on Vimeo