TY - CHAP A1 - Doyon, Anke A1 - Schmiedchen, Bettina A1 - Bayazit, Aysun A1 - Canpolat, Nur A1 - Duzova, Ali A1 - Kracht, Daniela A1 - Litwin, Mieczyslaw A1 - Niemirska, Anna A1 - Sozeri, Betul A1 - Zeller, Rene A1 - Anarat, Ali A1 - Caliskan, Salim A1 - Mir, Sevgi A1 - Shroff, Rukshana A1 - Melk, Anette A1 - Wühl, Elke A1 - Schweigert, Florian J. A1 - Querfeld, Uwe A1 - Schäfer, Franz T1 - Altered arterial morphology and function in children with CKD Role of mineral-bone disorder T2 - Pediatric nephrology : journal of the International Pediatric Nephrology Association Y1 - 2012 SN - 0931-041X VL - 27 IS - 9 SP - 1606 EP - 1607 PB - Springer CY - New York ER - TY - CHAP A1 - Doyon, Anke A1 - Schmiedchen, Bettina A1 - Bayazit, Aysun A1 - Canpolat, Nur A1 - Duzova, Ali A1 - Kracht, Daniela A1 - Litwin, Mieczyslaw A1 - Niemirska, Anna A1 - Sozeri, Betul A1 - Zeller, Rene A1 - Ranchin, Bruno A1 - Anarat, Ali A1 - Caliskan, Salim A1 - Mir, Sevgi A1 - Melk, Anette A1 - Wühl, Elke A1 - Schweigert, Florian J. A1 - Querfeld, Uwe A1 - Schäfer, Franz T1 - Distribuion and determinants of serum vitamin d concentrations in european children with chronic kidney disease T2 - Pediatric nephrology : journal of the International Pediatric Nephrology Association Y1 - 2012 SN - 0931-041X VL - 27 IS - 9 SP - 1627 EP - 1628 PB - Springer CY - New York ER - TY - JOUR A1 - Schmiedchen, Bettina A1 - Longardt, Ann Carolin A1 - Buehrer, Christoph A1 - Raila, Jens A1 - Loui, Andrea A1 - Schweigert, Florian J. T1 - The relative dose response test based on retinol-binding protein 4 is not suitable to assess vitamin A status in very low birth weight infants JF - Neonatology : fetal and neonatal research KW - Relative dose response test KW - Vitamin A KW - Preterm infant Y1 - 2014 U6 - https://doi.org/10.1159/000356773 SN - 1661-7800 SN - 1661-7819 VL - 105 IS - 2 SP - 155 EP - 160 PB - Karger CY - Basel ER - TY - GEN A1 - Paßlack, Nadine A1 - Schmiedchen, Bettina A1 - Raila, Jens A1 - Schweigert, Florian J. A1 - Stumpff, Friederike A1 - Kohn, Barbara A1 - Neumann, Konrad A1 - Zentek, Jürgen T1 - Impact of increasing dietary calcium levels on calcium excretion and vitamin D metabolites in the blood of healthy adult cats T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Background Dietary calcium (Ca) concentrations might affect regulatory pathways within the Ca and vitamin D metabolism and consequently excretory mechanisms. Considering large variations in Ca concentrations of feline diets, the physiological impact on Ca homeostasis has not been evaluated to date. In the present study, diets with increasing concentrations of dicalcium phosphate were offered to ten healthy adult cats (Ca/phosphorus (P): 6.23/6.02, 7.77/7.56, 15.0/12.7, 19.0/17.3, 22.2/19.9, 24.3/21.6 g/kg dry matter). Each feeding period was divided into a 10-day adaptation and an 8-day sampling period in order to collect urine and faeces. On the last day of each feeding period, blood samples were taken. Results Urinary Ca concentrations remained unaffected, but faecal Ca concentrations increased (P < 0.001) with increasing dietary Ca levels. No effect on whole and intact parathyroid hormone levels, fibroblast growth factor 23 and calcitriol concentrations in the blood of the cats were observed. However, the calcitriol precursors 25(OH)D-2 and 25(OH)D-3, which are considered the most useful indicators for the vitamin D status, decreased with higher dietary Ca levels (P = 0.013 and P = 0.033). Increasing dietary levels of dicalcium phosphate revealed an acidifying effect on urinary fasting pH (6.02) and postprandial pH (6.01) (P < 0.001), possibly mediated by an increase of urinary phosphorus (P) concentrations (P < 0.001). Conclusions In conclusion, calcitriol precursors were linearly affected by increasing dietary Ca concentrations. The increase in faecal Ca excretion indicates that Ca homeostasis of cats is mainly regulated in the intestine and not by the kidneys. Long-term studies should investigate the physiological relevance of the acidifying effect observed when feeding diets high in Ca and P. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 542 KW - chronic kidney-disease KW - growth-factor 23 KW - parathyroid-hormone KW - urinary ph KW - phosphorus KW - FGF23 KW - deficiency KW - dogs KW - hypercalciuria KW - secretion Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411302 SN - 1866-8372 IS - 542 ER - TY - JOUR A1 - Schmiedchen, Bettina A1 - Longardt, Ann Carolin A1 - Loui, Andrea A1 - Buehrer, Christoph A1 - Raila, Jens A1 - Schweigert, Florian J. T1 - Effect of vitamin A supplementation on the urinary retinol excretion in very low birth weight infants JF - European journal of pediatrics : official organ of the Belgian Pediatric Association N2 - Despite high-dose vitamin A supplementation of very low birth weight infants (VLBW, <1500 g), their vitamin A status does not improve substantially. Unknown is the impact of urinary retinol excretion on the serum retinol concentration in these infants. Therefore, the effect of high-dose vitamin A supplementation on the urinary vitamin A excretion in VLBW infants was investigated. Sixty-three VLBW infants were treated with vitamin A (5000 IU intramuscular, 3 times/week for 4 weeks); 38 untreated infants were classified as control group. On days 3 and 28 of life, retinol, retinol-binding protein 4 (RBP4), glomerular filtration rate, proteinuria, and Tamm-Horsfall protein were quantified in urine. On day 3 of life, substantial retinol and RBP4 losses were found in both groups, which significantly decreased until day 28. Notwithstanding, the retinol excretion was higher (P<0.01) under vitamin A supplementation as compared to infants of the control group. On day 28 of life, the urinary retinol concentrations were predictive for serum retinol concentrations in the vitamin A treated (P<0.01), but not in the control group (P=0.570). Conclusion: High urinary retinol excretion may limit the vitamin A supplementation efficacy in VLBW infants. Advanced age and thus postnatal kidney maturation seems to be an important contributor in the prevention of urinary retinol losses. KW - Vitamin A supplementation KW - RBP4 KW - Very low birth weight infant KW - Urine excretion Y1 - 2016 U6 - https://doi.org/10.1007/s00431-015-2647-9 SN - 0340-6199 SN - 1432-1076 VL - 175 SP - 365 EP - 372 PB - Springer CY - New York ER - TY - JOUR A1 - Passlack, Nadine A1 - Schmiedchen, Bettina A1 - Raila, Jens A1 - Schweigert, Florian J. A1 - Stumpff, Friederike A1 - Kohn, Barbara A1 - Neumann, Konrad A1 - Zentek, Juergen T1 - Impact of Increasing Dietary Calcium Levels on Calcium Excretion and Vitamin D Metabolites in the Blood of Healthy Adult Cats JF - PLoS one N2 - Background Dietary calcium (Ca) concentrations might affect regulatory pathways within the Ca and vitamin D metabolism and consequently excretory mechanisms. Considering large variations in Ca concentrations of feline diets, the physiological impact on Ca homeostasis has not been evaluated to date. In the present study, diets with increasing concentrations of dicalcium phosphate were offered to ten healthy adult cats (Ca/phosphorus (P): 6.23/6.02, 7.77/7.56, 15.0/12.7, 19.0/17.3, 22.2/19.9, 24.3/21.6 g/kg dry matter). Each feeding period was divided into a 10-day adaptation and an 8-day sampling period in order to collect urine and faeces. On the last day of each feeding period, blood samples were taken. Results Urinary Ca concentrations remained unaffected, but faecal Ca concentrations increased (P < 0.001) with increasing dietary Ca levels. No effect on whole and intact parathyroid hormone levels, fibroblast growth factor 23 and calcitriol concentrations in the blood of the cats were observed. However, the calcitriol precursors 25(OH)D-2 and 25(OH)D-3, which are considered the most useful indicators for the vitamin D status, decreased with higher dietary Ca levels (P = 0.013 and P = 0.033). Increasing dietary levels of dicalcium phosphate revealed an acidifying effect on urinary fasting pH (6.02) and postprandial pH (6.01) (P < 0.001), possibly mediated by an increase of urinary phosphorus (P) concentrations (P < 0.001). Conclusions In conclusion, calcitriol precursors were linearly affected by increasing dietary Ca concentrations. The increase in faecal Ca excretion indicates that Ca homeostasis of cats is mainly regulated in the intestine and not by the kidneys. Long-term studies should investigate the physiological relevance of the acidifying effect observed when feeding diets high in Ca and P. Y1 - 2016 U6 - https://doi.org/10.1371/journal.pone.0149190 SN - 1932-6203 VL - 11 SP - 47 EP - 67 PB - PLoS CY - San Fransisco ER - TY - THES A1 - Schmiedchen, Bettina T1 - Vitamin D and its linkage between chronic kidney disease and cardiovascular integrity Y1 - 2014 ER - TY - GEN A1 - Schmiedchen, Bettina A1 - Longardt, Ann Carolin A1 - Bührer, Christoph A1 - Raila, Jens A1 - Loui, Andrea A1 - Schweigert, Florian J. T1 - The Relative Dose Response Test Based on Retinol-Binding Protein 4 Is Not Suitable to Assess Vitamin A Status in Very Low Birth Weight Infants N2 - Background: The relative dose response (RDR) test, which quantifies the increase in serum retinol after vitamin A administration, is a qualitative measure of liver vitamin A stores. Particularly in preterm infants, the feasibility of the RDR test involving blood is critically dependent on small sample volumes. Objectives: This study aimed to assess whether the RDR calculated with retinol-binding protein 4 (RBP4) might be a substitute for the classical retinol-based RDR test for assessing vitamin A status in very preterm infants. Methods: This study included preterm infants with a birth weight below 1,500 g (n = 63, median birth weight 985 g, median gestational age 27.4 weeks) who were treated with 5,000 IU retinyl palmitate intramuscularly 3 times a week for 4 weeks. On day 3 (first vitamin A injection) and day 28 of life (last vitamin A injection), the RDR was calculated and compared using serum retinol and RBP4 concentrations. Results: The concentrations of retinol (p < 0.001) and RBP4 (p < 0.01) increased significantly from day 3 to day 28. On day 3, the median (IQR) retinol-RDR was 27% (8.4-42.5) and the median RBP4-RDR was 8.4% (-3.4 to 27.9), compared to 7.5% (-10.6 to 20.8) and -0.61% (-19.7 to 15.3) on day 28. The results for retinol-RDR and RBP4-RDR revealed no significant correlation. The agreement between retinol-RDR and RBP4-RDR was poor (day 3: Cohen's κ = 0.12; day 28: Cohen's κ = 0.18). Conclusion: The RDR test based on circulating RBP4 is unlikely to reflect the hepatic vitamin A status in preterm infants. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 342 KW - relative dose response test KW - vitamin A KW - preterm infant Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-399853 ER -