Phosphate homeostasis in Bartter syndrome: a case-control study.

BACKGROUND: Bartter patients may be hypercalciuric. Additional abnormalities in the metabolism of calcium, phosphate, and calciotropic hormones have occasionally been reported. METHODS: The metabolism of calcium, phosphate, and calciotropic hormones was investigated in 15 patients with Bartter syndrome and 15 healthy subjects. RESULTS: Compared to the controls, Bartter patients had significantly reduced plasma phosphate {mean [interquartile range]:1.29 [1.16-1.46] vs. 1.61 [1.54-1.67] mmol/L} and maximal tubular phosphate reabsorption (1.16 [1.00-1.35] vs. 1.41 [1.37-1.47] mmol/L) and significantly increased parathyroid hormone (PTH) level (6.1 [4.5-7.7] vs. 2.8 [2.2-4.4] pmol/L). However, patients and controls did not differ in blood calcium, 25-hydroxyvitamin D, alkaline phosphatase, and osteocalcin levels. In patients, an inverse correlation (P < 0.05) was noted between total plasma calcium or glomerular filtration rate and PTH concentration. A positive correlation was also noted between PTH and osteocalcin concentrations (P < 0.005), as well as between chloriduria or natriuria and phosphaturia (P < 0.001). No correlation was noted between calciuria and PTH concentration or between urinary or circulating phosphate and PTH. CONCLUSIONS: The results of this study demonstrate a tendency towards renal phosphate wasting and elevated circulating PTH levels in Bartter patients.

Effectiveness of recall systems for improving influenza vaccination coverage in children with oncohematological malignancies.

In order to verify whether a telephone recall system directly managed by the pediatricians who usually follow up the children for their cancer, with influenza vaccine administered in the oncological clinic, is more effective than an anonymous recall system, 205 children with oncohematological malignancies were randomised to one of three intervention strategies for increasing influenza vaccination coverage. The results showed that all of the strategies were useful in increasing influenza vaccination coverage, but the efficacy of recall was optimal only in the children who had completed chemotherapy since less than six months.

Impact of influenza-like illness and effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy.

In order to evaluate the impact of influenza-like illness and the effectiveness of influenza vaccination in children with oncohematological disease who have completed cancer therapy, 182 children with a diagnosis of oncohematological disease were divided into two subgroups on the basis of the length of time off therapy (<6 months or 6-24 months) and randomised 1:1 to receive influenza vaccination or not. The controls were 91 otherwise healthy children unvaccinated against influenza. The results show that the clinical and socioeconomic impact of influenza-like illnesses and the effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy are related to the length of the off therapy period, and seem to be significantly greater in those who have been off therapy for less than 6 months in comparison with healthy controls. This suggests that the administration of influenza vaccination should be strongly recommended only among oncohematological children who have been off therapy for less than 6 months.