METABOLISM OF METHIONINE IN THE NEWBORN INFANT

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。本研究的目的是定量研究含硫必需氨基酸蛋氨酸在健康足月儿和低出生体重儿体内的代谢动力学和代谢。健康的足月婴儿将从正常的新生儿托儿所招募，而低出生体重(早产)婴儿将从新生儿重症监护病房招募。通过使用稳定的、非放射性的蛋氨酸、苯丙氨酸和尿素同位素示踪剂，研究人员建议量化蛋氨酸的动力学及其与全身蛋白质分解(用苯丙氨酸Ra测量)和全身蛋白质氧化速率(用尿素产量测量)之间的关系。在足月儿中，经过三个小时的基础研究，将检查肠内营养(配方)对上述参数的影响。研究总时长为7小时：基础3小时，间歇(每30分钟)反应4小时。足月儿将定期进行呼吸量热计测量。将定期从留置静脉插管中抽取血液样本。对LBW婴儿进行研究时，他们每天摄入3.0g/kg的氨基酸，持续至少24小时，而不是通过肠道喂养。这些研究意义重大，因为它们将产生重要的数据，这些数据可能为新生儿补充(或不补充)半胱氨酸(由蛋氨酸形成的含硫氨基酸)提供理论基础。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study is to quantify the kinetics and metabolism of methionine (transsulfuration pathway), a sulfur containing essential amino acid, in healthy full term babies and in low birth weight infants. Healthy full term babies will be recruited from the normal newborn nursery while low birth weight (premature) infants will be recruited from the Neonatal Intensive Care Unit. By using stable, non-radioactive isotopic tracers of methionine, phenylalanine and urea, the investigators propose to quantify the kinetics of methionine and its relation to whole body protein breakdown (measured by phenylalanine Ra) and whole body rate of protein oxidation (measured by production of urea). In full term infants, after a three-hour basal study, the effect of enterally administered nutrients (formula) on the above parameters will be examined. The total duration of study will be seven hours: three hours basal and four hours of response to intermittent (every 30 minute) feeds. Respiratory calorimetry measurements will be done at periodic intervals in term infants. Blood samples from indwelling venous cannula will be drawn at periodic intervals. The LBW infants will be studied while they are receiving parenteral amino acid at 3.0 g/kg/d for at least 24 hours and not enterally fed. The studies are significant in that they will generate important data which may provide the rationale for supplementation (or not) of cysteine (sulfur amino acid, formed from methionine) in the newborn infant.