Pituitary iron and volume predict hypogonadism in transfusional iron overload

Hypogonadism is the most common morbidity in patients with transfusion‐dependent anemias such as thalassemia major. We used magnetic resonance imaging (MRI) to measure pituitary R2 (iron) and volume to determine at what age these patients develop pituitary iron overload and volume loss. We recruited 56 patients (47 with thalassemia major, five with chronically transfused thalassemia intermedia and four with Blackfan‐Diamond syndrome) to have pituitary MRIs to measure pituitary R2 and volume. Hypogonadism was defined clinically based on the timing of secondary sexual characteristics or the need for sex hormone replacement therapy. Patients with transfusional iron overload begin to develop pituitary iron overload in the first decade of life; however, clinically significant volume loss was not observed until the second decade of life. Severe pituitary iron deposition (Z > 5) and volume loss (Z < ?2.5) were independently predictive of hypogonadism. Pituitary R2 correlated significantly with serum ferritin as well as liver, pancreatic, and cardiac iron deposition by MRI. Log pancreas R2* was the best single predictor for pituitary iron, with an area under the receiving operator characteristic curve of 0.88, but log cardiac R2* and ferritin were retained on multivariate regression with a combined r² of 0.71. Pituitary iron overload and volume loss were independently predictive of hypogonadism. Many patients with moderate‐to‐severe pituitary iron overload retained normal gland volume and function, representing a potential therapeutic window. The subset of hypogonadal patients having preserved gland volumes may also explain improvements in pituitary function observed following intensive chelation therapy. Am. J. Hematol. 2011. © 2011 Wiley Periodicals, Inc.     

Liver regeneration after major hepatectomy. Evaluation of dogs hepatectomy

OBJECTIVES: The aim of our study is to evaluate anatomic regeneration and metabolic derangement of the liver after major resection in dogs. METHODS: This is an experimental study on 9 dogs; we divided the dogs in two groups: the first group (5 dogs) underwent at one go major hepatectomy (90% of the liver).The second group (4 dogs) underwent successively a resection of 75% of the liver and a second resection of 90% of the restored liver six months later. All dogs underwent a metabolic and morphologic studies of the liver and of their kidney function. RESULTS: In the first group; all dogs which underwent 90% hepatic resection died 48 hours after the surgical resection of hepatic insufficiency. The ultra microscopic study showed the role of portal hypertension in hepatic degeneration on the first group. In the second group, the dogs survived the first resection, and our study shows a regeneration of the liver after resection and sub normal hepatic function. CONCLUSION: The liver is able to regenerate after minimally resection but major resection must be done by successively resection to avoid hepatic dysfunction, but the time between resection must be evaluate later.     

Different approaches for patent ductus arteriosus in premature infants using acetaminophen

Background Acetaminophen use for pharmacological treatment of hemodynamically significant patent ductus arteriosus(hsPDA)in preterm infants is becoming more pop...     

COS-derived GPP relationships with temperature and light help explain high-latitude atmospheric CO2 seasonal cycle amplification

In the Arctic and Boreal region (ABR) where warming is especially pronounced, the increase of gross primary production (GPP) has been suggested as an important driver for the increase of the atmospheric CO₂ seasonal cycle amplitude (SCA). However, the role of GPP relative to changes in ecosystem respiration (ER) remains unclear, largely due to our inability to quantify these gross fluxes on regional scales. Here, we use atmospheric carbonyl sulfide (COS) measurements to provide observation-based estimates of GPP over the North American ABR. Our annual GPP estimate is 3.6 (2.4 to 5.5) PgC · y⁻¹ between 2009 and 2013, the uncertainty of which is smaller than the range of GPP estimated from terrestrial ecosystem models (1.5 to 9.8 PgC · y⁻¹). Our COS-derived monthly GPP shows significant correlations in space and time with satellite-based GPP proxies, solar-induced chlorophyll fluorescence, and near-infrared reflectance of vegetation. Furthermore, the derived monthly GPP displays two different linear relationships with soil temperature in spring versus autumn, whereas the relationship between monthly ER and soil temperature is best described by a single quadratic relationship throughout the year. In spring to midsummer, when GPP is most strongly correlated with soil temperature, our results suggest the warming-induced increases of GPP likely exceeded the increases of ER over the past four decades. In autumn, however, increases of ER were likely greater than GPP due to light limitations on GPP, thereby enhancing autumn net carbon emissions. Both effects have likely contributed to the atmospheric CO₂ SCA amplification observed in the ABR.

Gross primary production (GPP) is the total amount of carbon that is taken up from the atmosphere and converted to sugars by plants during photosynthesis. It is the primary source of organic matter production on Earth. GPP is also central to the carbon cycle and for understanding carbon feedbacks to climate. Currently, it exceeds ecosystem respiration (ER) and controls the overall direction of land carbon sequestration on a global scale, thus having a cooling effect on climate. However, carbon cycle–based terrestrial feedbacks in the future have substantial uncertainties and therefore represent one of the largest uncertainties in climate projections (1). A large source of this uncertainty stems from our inability to quantify GPP at large spatial scales and our incomplete understanding of the sensitivity of GPP to rising atmospheric CO₂ concentrations and air temperature (2, 3).In the Arctic and Boreal regions, where climate warming has been magnified by more than a factor of 2 relative to other regions of the globe (4, 5), the growth of GPP is thought to have contributed to an increase in the atmospheric CO₂ mole fraction seasonal cycle amplitude (SCA) observed over the northern high latitudes (6, 7), either due to an earlier onset or lengthening of the growing season (6, 8, 9) or enhanced carbon uptake (7, 10), although increased respiration (11, 12) and transport from midlatitudes (13, 14) also contribute.Despite the vital role of GPP in the carbon cycle, climate, and food systems, its magnitudes and trends over the Arctic and Boreal regions are poorly known. Annual GPP estimated from terrestrial ecosystem models (TEMs) and machine learning methods (15, 16) differ by as much as a factor of 6 (Fig. 1 and SI Appendix, Fig. S1). Given this large uncertainty, the current capability for constraining GPP on regional scales remains very limited. No direct GPP measurements can be made at scales larger than at a leaf level, because the basic process of GPP, which extracts CO₂ from the atmosphere, is countered by the production of CO₂ for respiration. Although large-scale GPP estimates have been made by machine learning methods (15, 16), light-use efficiency models (17), empirical models (18), and terrestrial biogeochemical process models (19–21) that have been trained on small-scale net CO₂ fluxes measured by eddy covariance towers, they substantially differ in mean magnitude, interannual variability, trends, and spatial distributions of inferred GPP (22–24). Satellite remote-sensing measurements of solar-induced chlorophyll fluorescence (SIF) and near-infrared reflectance of vegetation (NIRv) have been strongly linked to GPP on regional and global seasonal scales (25–28). However, GPP estimates based on scaling of SIF and NIRv can be limited by inconsistent and poorly constrained scaling factors among different plant functional types (29) or can be biased from interferences of clouds and aerosols in retrievals (30).Open in a separate windowFig. 1.Regional GPP for the North American ABR, estimated from bottom-up terrestrial models participating in Multiscale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) (dashed lines), FluxCom (cyan squares with solid lines), FluxSat (green triangles with solid lines), and SiB4 (red circles with solid lines) and our top-down atmospheric COS inversions (dark gray shading indicates the 2.5th to 97.5th of our best inversion ensemble estimates, whereas the light gray shading denotes the range of our best ensemble estimates plus 2σ uncertainties from each inversion). The North American ABR is indicated in B. (A) Annual GPP estimates between 2000 and 2019. (B) Multiyear average seasonal cycle of GPP from MsTMIP (2008–2010), FluxSat (2001–2019), FluxCom (2001–2018), SiB4 (2009–2013), and this study (2009–2013). (C) Spatial distribution of GPP in July 2010 from three selected TEMs (LPJ-wsl, SiB4, and DLEM) and average GPP from July in 2009 to 2013 derived from COS-based inversions. The spatial distribution of GPP from other TEMs is shown in SI Appendix, Fig. S12.Table 1.Annual COS fluxes and GPP over the North American ABR, estimated from process-based bottom-up approaches and our atmosphere-based top-down method

The subgenusPersicargas (ixodoidea: Argasidae:Argas). 35. The lateral segmental organs and peritracheal gland in immature and adultA. (P.) arboreus

Lateral segmental organs and a peritracheal gland in adult and immatureArgas (Persicargas) arboreus are described and compared with similar organs in other arthropods. Four pairs of lateral segmental organs containing neuronal cell bodies and innervated by branches of hemal nerves from pedal nerve roots are present in nymphal instars and in the adult; 3 pairs are present in the larva. In each postembryonic developmental stage, the peritracheal gland consists of cell masses with neurosecretory granular activity and is associated with the tracheal plexus in the region of the central nerve mass and adjacent hypodermis. The glandular cells show cyclic changes in size and activity related to the molting process in immature stages and probably to other events in the adult.Request offprints from Medical Zoology Department, NAMRU-3, FPO, New York 09527, USAFrom Research Project MR041.05.01-0067, Naval Medical Research and Development Command, National Naval Medical Center, Bethesda, Maryland, USA. The opinions and assertions contained herein are the private ones of the authors and are not to be construed as official or as reflecting the views of the Department of the Navy or of the naval service at large