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    Adrenomedullin and nitrite levels in children with Bartter syndrome
    (Springer-Verlag, 2000) Balat, A; Çekmen, M; Yürekli, M; Kutlu, O; Islek, I; Sönmezgöz, E; Çakir, M
    Children with Bartter syndrome have lower than normal vascular reactivity with normotension in spite of biochemical and hormonal abnormalities which are typical of hypertension. Nitric oxide (NO) is a potent endogenous vasodilator, and plays an important role in the control of vascular tone. Adrenomedullin (AM) is a novel hypotensive peptide originally isolated from human pheochromocytoma. The possible role of NO and PLM in maintaining this reduced vascular reactivity was examined by studying plasma and urinary nitrite, a stable metabolite of NO, and AM levels in ten children with Bartter syndrome, ten healthy controls, and five children with hypokalemia of causes other than Bartter syndrome (pseudo-Bartter). Urinary excretion of nitrite (mu mol/mg urinary creatinine) was 8.9.+/-1.2 in children with Bartter syndrome, 4.7.+/-0.9 in healthy controls, and 2.9.+/-0.8 in pseudo-Bartter (P<0.05). Plasma nitrite levels (mol/l) were 101.9+/-23.4, 59.9+/-14.7, and 65.0+/-29.7, respectively (P>0.05), in the three groups. Urinary excretion of AM (pmol/mg urinary creatinine) was 187+/-40, 65+/-10, and 160+/-50, respectively (P<0.05), in the three groups. Plasma AM levels were 47.4+/-1.8, 39.9+/-5.9, and 42.4+/-3.9, respectively (P>0.05), in the three groups. The same parameters were repeated in the two groups of controls and in the Bartter patients in the 6th month of therapy. Urinary nitrite and AM levels were still higher in the Bartter patients than in the other groups. We conclude that in Bartter syndrome the increased NO production may be responsible for the reduced vascular response of the disease. Initially, increased levels of AM in Bartter syndrome and pseudo-Bartter may be a compensatory response to acute hypokalemia; however, continuation of a high level of urinary excretion of AM in children with Bartter syndrome may suggest also the possible role of AM in the reduced vascular response of the disease.
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    Adrenomedullin and total nitrite levels in children with familial Mediterranean fever
    (Blackwell Publishing, 2006) Balat, A; Islek, I; Çekmen, M; Yürekli, M; Tekin, D; Muslu, A; Sahinöz, S
    Aim: Familial Mediterranean fever (FMF) is the most frequent periodic syndrome characterised by recurrent attacks of polyserositis. However, recent studies revealed that there might be an ongoing subclinical inflammation between the attacks. As nitric oxide (NO) and adrenomedullin (AM) are both synthesised in the endothelium, and mediates many functions within immune system, we considered them to be an interesting target of investigation in FMF. Methods: Fifteen children with FMF receiving regular colchicine, ranging in age from 3 to 16 years, were investigated in comparison with 15 healthy age- and sex-matched controls. The mean age of the patients was 9.7 +/- 3.9 years. Total nitrite, a stable product of NO, was quantitated by means of the Griess reaction, while AM was measured by HPLC. Results: Plasma-urinary AM and total nitrite levels were significantly higher in children with FMF. Plasma AM levels (pmol/mL) in patients and controls were 40.95 +/- 5.99 vs. 34.86 +/- 5.24, P < 0.05, and urinary AM excretion (pmol/mg creatinine) was 51.16 +/- 28.15 vs. 37.5 +/- 24.26, P < 0.05 respectively. Plasma total nitrite levels (mu mol/L) in patients and controls were 44.80 +/- 10.36 vs. 32.13 +/- 9.28, P < 0.05, and urinary nitrite excretion (mu mol/mg creatinine) was 2.24 +/- 1.71 vs. 1.09 +/- 0.96, P < 0.05 respectively. Conclusion: This study considered that AM and NO may have a role in the immuno-inflammatory process of FMF, although, whether these act to preserve, or protect against, further inflammatory injury is not clear. Our results further supports the hypothesis that these patients have subclinical inflammation between attacks.
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    Adrenomedullin and total nitrite levels in children with Henoch-Schonlein purpura
    (Springer, 2003) Islek, I; Balat, A; Çekmen, M; Yürekli, M; Muslu, A; Sahinöz, S; Sivasli, E
    Nitric oxide (NO) is synthesized from endothelium and has an important role in the control of vascular tonus. Adrenomedullin (AM) is a potent vasodilator, and cytoprotective peptide is produced not only in adrenal medulla, but also in the vascular smooth muscle and endothelial cells. To investigate the endothelial synthesis of AM and NO, and endothelial injury in Henoch-Schonlein purpura (HSP), we measured their levels in 16 children with HSP, who were evaluated during the acute and remission phases, and compared with 12 healthy controls. Plasma AM levels (pmol/ml) were significantly higher in acute phase children (46.87+/-11.49) than in those in remission (35.59+/-12.39, p<0.01) and controls (30.70+/-9.12, p<0.001). Similarly, plasma total nitrite levels (mumol/l) were higher in acute phase patients (47.50+/-12.30) than in those in remission (35.94+/-10.08, p<0.005) and controls (34.56+/-11.51, p<0.05). Urinary excretion of AM (pmol/mg creatinine) was higher in acute phase patients (53.85+/-23.22) than in remission patients (29.97+/-9.33, p<0.01) and controls (37.43+/-15.78, p<0.05). Patients had increased urinary nitrite excretion (mumol/mg creatinine) in acute phase (2.39+/-1.18) compared to those in remission (1.53+/-0.90, p<0.05) and controls (1.05+/-0.61, p<0.005). There was no significant difference between remission phase and controls in AM and nitrite levels (p>0.05). This study concluded that AM and NO may have a role in the immunoinflammatory process of HSP, especially in the active stage, although whether this perpetuates, or protects against, further vascular injury is not clear. Further studies are needed to clearly establish the roles of AM and NO in the pathogenesis of HSP.