The TeV Sun Rises: Discovery of Gamma rays from the Quiescent Sun with HAWC

We report the first detection of a TeV gamma-ray flux from the solar disk (6.3$\sigma$), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5--2.6 TeV spectrum is well fit by a power law, dN/dE = $A (E/1 \text{ TeV})^{-\gamma}$, with $A = (1.6 \pm 0.3) \times 10^{-12}$ TeV$^{-1}$ cm$^{-2}$ s$^{-1}$ and $\gamma = -3.62 \pm 0.14$. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.Comment: 15 pages, 8 figures including supplementary material. Accepted for publication in Physical Review Letter

Effects of uremic ultrafiltrate on the regulation of the parathyroid cell cycle by calcitriol

Effects of uremic ultrafiltrate on the regulation of the parathyroid cell cycle by calcitriol.BackgroundCalcitriol (CTR) is used in the treatment of hyperparathyroidism secondary to renal failure because it decreases parathyroid hormone (PTH) synthesis and parathyroid cell proliferation. Previous studies in tissues other than parathyroids have demonstrated that uremic factors affect the action of CTR on the target cells. We questioned whether the uremic milieu interferes with the inhibition of parathyroid cell proliferation by CTR.MethodsStudies were performed in vitro using freshly excised normal dog parathyroid tissue incubated for 24 hours with and without CTR and in the presence of either total uremic ultrafiltrate (UUF) from uremic patients or high-pressure liquid chromatography (HPLC)-derived fractions (hydrophilic compounds eluting early and hydrophobic compounds eluting late) of this UUF (F1 to F4). Parathyroid cell proliferation was assessed by flow cytometry.ResultsThe addition of CTR 10-8 and 10-7 mol/L to parathyroid tissue produced an inhibition of the proliferation that was prevented in the presence of UUF. In a medium containing CTR 10-8 mol/L, the addition of F1, F2 and F3, but not F4, prevented the CTR-induced inhibition of parathyroid cell proliferation. With CTR 10-7 mol/L, the inhibition of proliferation was observed even in the presence of F1, F2 and also F4, but was prevented by F3. Uric acid (7 mg/dL), indoxyl sulfate (5 mg/dL) and p-cresol (1.4 mg/dL), which coeluted with F1, F2 and F4, respectively, did not interfere with the inhibitory action of CTR 10-7 mol/L; however, the addition of phenol (0.14 mg/dL), which coeluted with F3, prevented the CTR-induced inhibition of parathyroid cell proliferation.ConclusionsThe presence of uremic toxins prevents the inhibition of parathyroid cell proliferation induced by calcitriol

First Spanish series of intestinal transplantation in adult recipients Primera serie nacional de trasplante de intestino en receptores adultos

Background: short-bowel transplantation has experienced a substantial growth worldwide following improved results from the late 1990s on, and its coverage by Medicare. According to the International Registry (1985-2005), a total of 1,292 intestinal trasplants for 1,210 patients in 65 hospitals across 20 countries have been carried out thus far. Objective: to know short-term (6 months) results regarding patient and graft survival from the first Spanish series of intestinal transplants in adult recipients. Material and methods: we present our experience in the assessment of 20 potential candidates to short-bowel transplantation between June 2004 and October 2005. Of these, 10 patients were rejected and 4 were transplanted, which makes up the sample of our study. Results: to this date 5 transplants have been carried out in 4 patients (2 retransplants, 2 desmoid tumors, 1 short bowel syndrome after excision as a result of mesenteric ischemia). Upon study completion and after a mean follow-up of 180 days (range 90-190 days) all recipients are alive, and all grafts but one (75%) are fully operational, with complete digestive autonomy. All patients received induction with alemtuzumab except one, who received thymoglobulin; in all induction was initiated with no steroids. Conclusions: intestinal transplantation represents a therapeutic option that is applicable in our setting and valid for recipients with an indication who have no other feasible alternative to keep their intestinal failure under control