Histology of the regenerate and docking site in bone transport

Bone transport is based on the principle of distraction osteogenesis described by Ilizarov and is a consecrated method for the treatment of segmental bone defects. One of its most problematic and, paradoxically, least studied aspects is the consolidation of the docking site. We studied histologically the ossification of the docking site and regenerate to determine any difference between them. Nine adult sheep were submitted to correction of a 1-cm tibial diaphyseal defect using a system of plate-fixed bone transport, with latency period of 1 week and 0.2 mm distraction of the transported segment four times a day. The sheep were divided into three groups of three animals each, according to the observation period of 3, 6 or 12 weeks between the fixation of the transported fragment and the euthanasia. The docking site and the regenerate were studied histologically on sections stained with Masson trichrome. The main mode of docking site ossification was the endochondral one and although intramembranous ossification was also observed simultaneously, it was limited to rare and small foci. In contrast, intramembranous ossification played the major role in the regenerate, with bone formation evolving from the base segment to the target segment. The experimental bone transport model proposed in the present study permits us to conclude that there is a clear difference between the ossification of the docking site and of the regenerate.

Salt iodination and excessive iodine intake among schoolchildren

Salt iodination and excessive iodine intake among schoolchildren. The objective of the present study was to evaluate the urinary excretion of iodine and relate it to the amount present in salt for human consumption. The study involved 145 children from two schools: a rural one and an urban one. We performed anthropometric measurements and collected a urine sample and a kitchen salt sample from each child. In the rural school, 3.38% of children had iodine deficiency. However, most of the values of urinary iodine were above 300 mu g/L (62.03%) and 59.49% of the kitchen salt samples contained 20 to 60 mg iodine per kilo of salt. In the urban school, 3.03% of the children had urinary iodine excretion of less than 100 mu g/L and 90.91% of the children had urinary iodine values exceeding 300 mu g/L. Of this total, 84.85% of the kitchen salt samples contained 20 to 60 mg iodine per kilo of salt. Iodine deficiency is controlled in this population, with the current reality showing a high prevalence of excess urinary iodine.