Human growth hormone supplement promotes human lymphohematopoietic cell reconstitution in immunodeficient mice.

Aim: To investigate the potential of human growth hormone (hGH) to improve human hematopoietic reconstitution in humanized mice. Materials & methods: Immunodeficient mice were conditioned by total body irradiation and transplanted with human CD34+ fetal liver cells. Peripheral blood, spleen and bone marrow were harvested, and levels of human lymphohematopoietic cells were determined by flow cytometry. Results: Supplementation with hGH elevated human lymphohematopoietic chimerism by more than twofold. Treatment with hGH resulted in significantly increased reconstitution of human B cells and myeloid cells in lymphoid organs, enhanced human erythropoiesis in the bone morrow, and improved engraftment of human hematopoietic stem cells. Conclusion: hGH supplementation promotes human lymphohematopoietic reconstitution in humanized mice.

Humanized mice generated by human hematopoietic stem cell transplantation play crucial roles in biomedical investigations. One of the factors hindering the efficacy of their construction is the lack of or insufficient interaction of human cells to mouse cytokines and growth hormones (GHs) that are crucial for hematopoiesis and immune cell differentiation. In this study, we show that injection of human GH significantly improved human hematopoietic stem cell engraftment and function, as well as immune cell reconstitution in humanized mice. Our findings indicate that human cells may not efficiently respond to mouse GH, and generation of immunodeficient mice producing human GH may improve the efficacy of humanized mouse construction.

Phosphorus and mortality risk in end-stage renal disease: A meta-analysis.

BACKGROUND: Studies on the association of abnormal serum phosphorus level with all-cause mortality in patients with end-stage renal disease (ESRD) have yielded inconsistent results. OBJECTIVE: To evaluate the association of abnormal serum phosphorus level with all-cause mortality in patients with ESRD requiring dialysis by conducting a meta-analysis. METHODS: Pubmed and Embase databases were searched through March 2017 to identify all observational studies that assessed the association between abnormal serum phosphorus level and all-cause mortality risk in patients with ESRD requiring dialysis. Pooled hazard risk (HR) with 95% confidence interval (CI) was calculated for the highest versus referent phosphorus category and lower versus referent phosphorus category, separately. RESULTS: Nine cohort studies were eligible for analysis. During 12 to 97.6months follow-up duration, 24,463 death events occurred among 1,992,869 ESRD patients. Meta-analysis showed that the pooled HR of all-cause mortality was 1.16 (95% CI 1.06-1.28) for the lower versus referent serum phosphorus category. Similarly, patients with highest serum phosphorus levels were associated with an increased risk of all-cause mortality (HR 1.39; 95% CI 1.31-1.47) compared with those in the referent phosphorus category. Subgroup analyses revealed that the effect of phosphorus on the all-cause mortality risk appeared to be stronger within 2years follow-up. CONCLUSIONS: Both very high and very low values of phosphorus are independently associated with an increased risk for all-cause mortality in ESRD patients requiring dialysis. This meta-analysis highlighted a non-linear association of serum phosphorus with all-cause mortality among dialysis-dependent ESRD patients.

Microbial community composition is related to soil biological and chemical properties and bacterial wilt outbreak.

Soil microbes play important roles in plant growth and health. Little is known about the differences of soil microbes between healthy and bacterial wilt infected soils with Ralstonia solanacearum. By Illumina-MiSeq sequencing of 16S rRNA and 18S rRNA gene amplicons, we found the soil microbial composition and diversity were distinct between healthy and bacterial wilt infected soils. Soil microbial community varied at different plant growth stages due to changes of root exudates composition and soil pH. Healthy soils exhibited higher microbial diversity than the bacterial wilt infected soils. More abundant beneficial microbes including Bacillus, Agromyces, Micromonospora, Pseudonocardia, Acremonium, Lysobacter, Mesorhizobium, Microvirga, Bradyrhizobium, Acremonium and Chaetomium were found in the healthy soils rather than the bacterial wilt infected soils. Compared to bacterial wilt infected soils, the activities of catalase, invertase and urease, as well as soil pH, available phosphorous and potassium content, were all significantly increased in the healthy soils. In a conclusion, the higher abundance of beneficial microbes are positively related the higher soil quality, including better plant growth, lower disease incidence, and higher nutrient contents, soil enzyme activities and soil pH.

Transport of nutrients and contaminants from ocean to island by emperor penguins from Amanda Bay, East Antarctic.

Penguins play important roles in the biogeochemical cycle between Antarctic Ocean and land ecosystems. The roles of emperor penguin Aptenodytes forsteri, however, are usually ignored because emperor penguin breeds in fast sea ice. In this study, we collected two sediment profiles (EPI and PI) from the N island near a large emperor penguin colony at Amanda Bay, East Antarctic and performed stable isotope and element analyses. The organic C/N ratios and carbon and nitrogen isotopes suggested an autochthonous source of organic materials for the sediments of EPI (C/N = 10.21 ± 0.28, n = 17; δ(13)C = -13.48 ± 0.50‰, δ(15)N = 8.35 ± 0.55‰, n = 4) and an allochthonous source of marine-derived organic materials for the sediments of PI (C/N = 6.15 ± 0.08, δ(13)C = -26.85 ± 0.11‰, δ(15)N = 21.21 ± 2.02‰, n = 20). The concentrations of total phosphorus (TP), selenium (Se), mercury (Hg) and zinc (Zn) in PI sediments were much higher than those in EPI, the concentration of copper (Cu) in PI was a little lower, and the concentration of element lead (Pb) showed no difference. As measured by the geoaccumulation indexes, Zn, TP, Hg and Se were from moderately to very strongly enriched in PI, relative to local mother rock, due to the guano input from juvenile emperor penguins. Because of its high trophic level and transfer efficiency, emperor penguin can transport a large amount of nutrients and contaminants from ocean to land even with a relatively small population, and its roles in the biogeochemical cycle between ocean and terrestrial environment should not be ignored.

Distribution and bioavailability of cadmium in ornithogenic coral-sand sediments of the Xisha archipelago, South China Sea.

Total cadmium (Cd) concentrations in four ornithogenic coral-sand sedimentary profiles displayed a strong positive correlation with guano-derived phosphorus, but had no correlation with plant-originated organic matter in the top sediments. These results indicate that the total Cd distributions were predominantly controlled by guano input. Bioavailable Cd and zinc (Zn) had a greater input rate in the top sediments with respect to total Cd and total Zn, and a positive correlation with total organic carbon (TOC) derived from plant humus. Multi-regression analysis showed that the total Cd and TOC explained over 80% of the variation of bioavailable Cd, suggesting that both guano and plant inputs could significantly influence the distribution of bioavailable Cd, and that plant biocycling processes contribute more to the recent increase of bioavailable Cd. A pollution assessment indicates that the Yongle archipelago is moderately to strongly polluted with guano-derived Cd.

The interaction of selenium and mercury in the accumulations and oxidative stress of rat tissues.

This study evaluates the interaction of selenium (Se) and mercury (Hg) in the accumulations and oxidative stress of rat tissues. Rats were divided into five groups including one control (n=9) and four treated groups including M-Hg (n=9), L-Hg+Se (n=11), M-Hg+Se (n=10), and H-Hg+Se (n=10) group. Treated groups of rats were instilled with different amounts of mercuric chloride (HgCl(2)) and dl-selenomethionine (SeMet) by gavage since pregnancy of their mothers. Atomic fluorescence spectroscopy (AFS) was applied for mercury and selenium quantification. Glutathione (GSH), malondialdehyde (MDA), and total superoxide dismutase (SOD) activity of tissues were detected using biochemical methods. Results showed that Hg was deposited mainly in kidney. Se could decrease Hg content in kidney but increase it in blood and liver. Hg decreased GSH and SOD and increased MDA levels in most detected tissues, while Se took on a counteraction effect in same tissues. This study suggests that interactions of Se and Hg affect their accumulation and Se may antagonize Hg-induced inhibition on organic activities.

Mercury-selenium association in antarctic seal hairs and animal excrements over the past 1,500 years.

Strong positive correlations between selenium (Se) and total mercury (HgT) contents in the liver of marine mammals and mercury mine workers in modern times have been documented in numerous investigations. Herein, we report a positive correlation between Se and HgT concentrations over the past 1,500 years in the seal hairs and in the lake sediments amended by seal or penguin excrements on King George Island (63 degrees 23' S, 57 degrees 00' W), West Antarctica. Because the changes in the input of Se and Hg into the marine environments of the studied sites do not seem to be synchronous, this striking correlation indicates a self-protection mechanism in Antarctic seals and penguins: Every time there is heavier Hg burden, more Se is accumulated to reduce the toxicity of Hg. This positive correlation between Hg and Se contents in the seal hairs and excrement sediments, however, becomes insignificant in the recent 50 years for unknown reasons.

P and trace metal contents in biomaterials, soils, sediments and plants in colony of red-footed booby (Sula sula) in the Dongdao Island of South China Sea.

Concentrations of P and trace metals Zn, Cu, Cd, Pb and Hg in the faeces, bones, eggshells and feathers of seabirds and in the plants, soils and sediments with and without seabird influence on Dongdao Island, South China Sea, were determined and analyzed. Among the seabird biomaterials, the levels of P, Zn, Cu and Cd are the highest in the droppings and several times those in other materials; the Hg concentration is the highest in the feathers; and the Pb content is comparable among these biomaterials. These marked differences indicate different intake-bioaccumulation-elimination pathways for different trace metals. The levels of P, Zn, Cu, Cd and Hg in the plant, soil and sediment samples with the influence of seabird droppings are significantly higher than those in the samples without, and they are significantly correlated with each other. Thus, P, Zn, Cu, Cd and Hg are very likely to have a common source-predominantly bird guano-and the faeces of red-footed booby is an important vector for the flux of nutrient phosphorus and trace metals Zn, Cu, Cd and Hg from marine to island ecosystems on Dongdao Island.