Longitudinal growth study of Tasmanian children. 2. The seven-year-olds

A longitudinal growth study of Tasmanian children, involving 1,114 infants born between September 1, 1967, and August 31, 1968, has continued into the seventh year during 1974-1975, when measurements of height and weight were recorded on the 898 remaining children that could be traced. A portion of the results is presented here. The main findings is that a high percentage of children who are overweight at the age of three years is likely to be overweight at seven years. Birth weight is not an important factor in determining the weight of a seven-year-old. Children over the 90th percentile at age three years are, on the average, more than 5 kg heavier at seven years than children between the 10th and 90th percentiles at three years. The seven-year-old weights themselves do not appear to have altered in the past two decades, being virtually identical to those in the 1957 Standard Tables for Australian Children.     

Biotin-binding protein from chicken egg yolk. Assay and relationship to egg-white avidin

1. Biotin in chicken egg yolk is non-covalently bound to a specific protein that comprises 0.03% of the total yolk protein (0.8 mg/yolk). This biotin-binding protein is not detectable by the normal avidin assay owing to the biotin being tightly bound. Exchange of [14C]biotin for bound biotin at 65 degrees C is the basis of an assay for this protein. 2. Biotin-binding protein from egg yolk is distinguishable from egg-white avidin on Sephadex G-100 gel filtration, although the sizes of the two proteins appear quite similar. 3. Biotin-binding protein is denatured at a lower temperature and freely exchanges biotin at lower temperatures than does avidin. 4. The biotin-binding protein in egg yolk is postulated to be responsible for the deposition of biotin in egg yolk. D-[carboxyl-14C]Biotin injected into laying hens rapidly appears in the egg bound to yolk biotin-binding protein and avidin. Over 60% of the radioactivity is eventually deposited in eggs. The kinetics of biotin deposition in the egg suggests a 25 day half-life for an intracellular biotinyl-coenzyme pool in the laying hen.     

Ectopic pregnancies associated with low dose progestagen-releasing IUDs

Dimethyl-polysiloxane capsules containing pure progestagens were attached to Tatum's T IUDs and tested in 594 fertile women for contraceptive performance. The control group was represented by 71 women who received identical devices containing barium sulphate instead of steroid and 100 women who received a Copper T-200. The progestagens and the doses tested were megestrol acetate (4.8, 19.2, 26 and 32 micrograms/day; levonorgestrel (2.1, 3.4 and 8.5 micrograms/day); norethindrone (18 micrograms/day); R2323 (28.6 and 45 micrograms/day); and norgestrienone (26 micrograms/day). Twelve pregnancies were diagnosed during 5201 woman-months of exposure accumulated within the first year of use among users of the steroid-bearing IUDs. Five of these were ectopic gestations. Ten pregnancies, all uterine, were detected during 1701 woman-months of exposure in the control group. Intrauterine delivery of progestagens by means of a carrier IUD is effective in decreasing the pregnancy rate but it might effect postovulatory events in a way which increases the rate of tubal implantation. Because of this property, progestagen-releasing IUDs should be limited to doses that assure maximal effectiveness to avoid increasing the risk of ectopic pregnancy.