CALCIUM KINETICS IN PREGNANT AND LACTATING ADOLESCENTS

孕妇和哺乳期青少年的钙动力学

• 批准号: 2857481
• 负责人: Kimberly O O'Brien
• 金额: $ 10.83万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-15 至 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2857481
• 关键词: adolescence (12-20); calcium; calcium metabolism; clinical research; estradiol; female; gastrointestinal nutrient absorption; hormone regulation /control mechanism; human subject; lactation; mother /embryo /fetus nutrition; normal ossification; nutrition related tag; osteocalcin; parathyroid hormones; pharmacokinetics; physiologic bone resorption; pregnancy; radionuclides; urinalysis; vitamin D

Adolescent pregnancy is a significant problem in the United States. Special nutritional concerns are present in this group to insure that optimal nutritional needs can be met by both the fetus and the growing adolescent. The additional nutritional demands of pregnancy may be of primary concern when the mother has not yet completed her linear growth and has not full achieved her peak bone mass. The aim of the proposed study is to address the impact of pregnancy and lactation on the efficiency of calcium absorption and rates of bone calcium deposition and resorption in adolescent non-Hispanic white and non-Hispanic black girls between the ages of 11-17 years. Fifteen girls from each group who intend to breastfeed their infants will participate in a longitudinal calcium kinetic study designed to address the efficiency of calcium absorption and rates of bone calcium turnover during both the third trimester of pregnancy (34-36 weeks of gestation) and during lactation (1-2 months post partum). All adolescents will be screened for positive predictors of lactation performance prior to the start of the study. In each kinetic study, girls will be admitted to the General Clinical Research Unit at Johns Hopkins Hospital. On the morning of each study, girls will consume a glass of milk containing a stable calcium isotope (46Ca), and following breakfast a second stable calcium isotope (42Ca) will be administered intravenously. Timed blood samples will be obtained for eight hours following the isotope dosing, and a complete 24 hour urine collection will be made. Additional spot urine samples will be collected for 5 days following each isotope study. To address the hormonal response to pregnancy and lactation, calcitropic hormones will be measured during each study using a fasting blood sample. Rates of bone calcium deposition and resorption in response to these physiological changes will be determined using multicompartmental modeling. These studies will provide novel information on the physiological alterations in calcium absorption and bone calcium turnover which occur to support both the increased calcium demands of adolescence and the calcium demands of pregnancy and lactation.

青少年怀孕是美国的一个严重问题。 该群体存在特殊的营养问题，以确保 胎儿和成长中的婴儿都能满足最佳营养需求 青少年。 怀孕期间额外的营养需求可能是 当母亲尚未完成线性生长时的主要关注点 并且尚未完全达到她的峰值骨量。 拟议的目标 研究的目的是解决怀孕和哺乳期对婴儿的影响 钙吸收效率和骨钙沉积率 青少年非西班牙裔白人和非西班牙裔黑人的吸收和吸收 11-17岁之间的女孩。 每组十五名女孩 打算母乳喂养婴儿的人将参加 纵向钙动力学研究旨在解决效率问题 钙吸收和骨钙周转率 妊娠晚期（妊娠 34-36 周）和期间 哺乳期（产后 1-2 个月）。 所有青少年都将接受筛查 开始前哺乳表现的积极预测因素 研究。 在每项动力学研究中，女孩将被录取到普通 约翰·霍普金斯医院临床研究室。 上午 每项研究中，女孩都会喝一杯含有稳定物质的牛奶 钙同位素 (46Ca)，早餐后第二次稳定钙 同位素 (42Ca) 将静​​脉注射。 定时血液样本 将在同位素给药后八小时内获得，并且 将进行完整的 24 小时尿液收集。 额外的点尿 每次同位素研究后将收集 5 天的样本。 到 解决怀孕和哺乳期的荷尔蒙反应，钙化 每次研究期间将使用空腹血液测量激素 样本。 骨钙沉积率和骨吸收率的响应 这些生理变化将使用多室确定 造型。这些研究将提供关于 钙吸收和骨钙的生理变化 营业额的发生是为了支持钙需求的增加 青春期以及怀孕和哺乳期的钙需求。