No abstract

We reviewed the growth characteristics of American boys and girls from published studies, including age at takeoff, age at peak height velocity, peak height velocity, duration of puberty, and the magnitude of the pubertal contribution to adult height. Age at takeoff is highly variable and sex-dependent. The mean takeoff age in children growing at an average rate is ∼11 years in boys and 9 years in girls, and peak height velocity occurs at a mean age of 13.5 years and 11.5 years, respectively, in these children. Whole-year peak height velocity is 9.5 cm/y in boys and 8.3 cm/y in girls, with slight variations in the different studies. The contribution of pubertal growth to final height is ∼30 to 31 cm in boys, accounting for 17% to 18% of the final height, and 27.5 to 29 cm in girls, accounting for 17% of the final height. The magnitude of pubertal growth has a negative correlation with age at takeoff, but no correlation with final height. Age at takeoff, however, correlates highly with pubertal stage, but correlates negatively with duration of puberty.

Polyinosinic polycytidilic acid (poly I:C), an inducer of alpha-interferon, accelerates the development of diabetes in diabetes-prone (DP) BioBreeding (BB) rats. This study investigates the effect of administering poly I:C to a diabetes-resistant (DR) strain of BB rats. We compared the incidence of diabetes, the degree of insulitis, the number of NK cells, helper-inducer cells, cytotoxic-suppressor cells, Ia+ T cells, RT6.1+ T cells, and NK cell bioactivity in DR rats treated with saline and with a 5 micrograms/g body wt (poly-5) dose and a 10 micrograms/g body wt (poly-10) dose of poly I:C. The incidence of diabetes was also compared with that of DP rats receiving poly-5. We found that both doses of poly I:C significantly induce the development of diabetes in the DR BB rat. However, treatment of DR rats with the higher dose induces a greater rate of development of diabetes and earlier onset of diabetes than the lower poly-5 dose. The rate of diabetes development and the mean age of onset were similar in poly-10-treated DR and poly-5-treated DP rats. A significant degree of insulitis occurred in all the poly I:C-treated DR rats, even those not developing diabetes. Peripheral blood NK cell number was greater in poly I:C than in saline-treated rats, after 2 wk of treatment and when killed. The percentage of OX19+ peripheral blood mononuclear cells expressing RT6.1 allotype or Ia antigen were similar in poly I:C- and saline-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)