| 1. |
- Jelen, Sabina, et al.
(författare)
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AQP9 Expression in Glioblastoma Multiforme Tumors Is Limited to a Small Population of Astrocytic Cells and CD15(+)/CalB(+) Leukocytes
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:9
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Tidskriftsartikel (refereegranskat)abstract
- Aquaporin-9 (AQP9) is a membrane protein channel that is permeable to a range of small solutes, including glycerol, urea and nucleobases. Expression of AQP9 in normal brain is limited, while widespread AQP9 expression has previously been reported in human glioblastoma. However, the specific cellular expression of AQP9 in glioblastoma remains unclear. In this study, we have examined microarrays to corroborate AQP9 mRNA expression in glioma. These analyses suggested that AQP9 mRNA expression in glioblastoma is primarily explained by tumor infiltration with AQP9 expressing leukocytes. Immunolabeling confirmed that within tumor regions, AQP9 was expressed in CD15(+) and Calgranulin B+ leukocytes, but also in larger cells that morphologically resembled glioma cells. Specificity of immunoreagents was tested in recombinant cell lines, leukocyte preparations, and sections of normal human brain and liver tissue. Apparent AQP9(+) glioma cells were frequently observed in proximity to blood vessels, where brain tumor stem cells have been observed previously. A fraction of these larger AQP9 expressing cells co-expressed the differentiated astrocyte marker GFAP. AQP9 expressing glioma cells were negative for the brain tumor stem cell marker CD15, but were observed in proximity to CD15(+) glioma cells. AQP9 expression may therefore require signals of the perivascular tumor environment or alternatively it may be restricted to a population of glioma stem cell early progenitor cells.
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| 2. |
- Mahler, Birgitte Thorsted, et al.
(författare)
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Puberty alters renal water handling.
- 2013
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Ingår i: American journal of physiology. Renal physiology. - : American Physiological Society. - 1522-1466 .- 1931-857X. ; 305:F1728-F1735
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the influence of sex and puberty stage on the circadian urine production and levels of antidiuretic hormone (AVP) in healthy children. Thirty-nine volunteers (9 prepuberty boys, 10 prepuberty girls, 10 midpuberty boys and 10 midpuberty girls) were included. All participants underwent a 24-hours circadian in-patient study under standardized conditions regarding sodium and fluid intake. Blood samples were drawn every four hours for measurements of plasma AVP, serum 17-β-estradiol and testosterone and the urine was fractionally collected for measurements of electrolytes, aquaporin 2 (AQP2) and prostaglandin E2 (PGE2). We found a marked night-time decrease in diuresis (from 1.69±0.08 to 0.86±0.06ml/kg/h,p<0.001) caused by a significant night-time increase in solute-free water reabsorption(TcH2O)(Day-Night ratio 0.64±0.07,p<0.001) concurrent with a significant decrease in osmotic excretion (Day-Night ratio 1.23±0.06,p<0.001). Plasma AVP expressed a circadian rhythm (p<0.01) with a night-time increase and peak levels at midnight (0.49±0.05 pg/ml). The circadian plasma AVP rhythm was not influenced by gender (p=0.56) or puberty stage (p=0.73). There was significantly higher night-time TcH2O in pre-puberty children. This concurred with increased night-time urinary AQP2 excretion in pre-puberty children. Urinary PGE2 exhibited circadian rhythm independent of sex or puberty stage. The levels of serum 17-β-estradiol and testosterone were as expected for sex and pubertal stage and no effect on AVP-AQP2- TcH2O axis was observed. This study finds a circadian rhythm of plasma AVP independent of sex and puberty stage, though night-time solute-free water reabsorption was higher and AQP2 excretion more pronounced in pre-puberty children suggesting higher pre-puberty renal AVP sensitivity.
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