ANALYSIS OF IN VIVO HPRT MUTATIONS IN PREMATURE INFANTS

早产儿体内 HPRT 突变分析

• 批准号: 6277158
• 负责人: ROBERT A SILVER
• 金额: $ 2.62万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-12-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6277158
• 关键词: DNA; DNA damage; T lymphocyte; clinical research; gene frequency; gene mutation; gestational age; human genetic material tag; human subject; medical records; molecular cloning; mutant; neoplasm /cancer genetics; premature infant human; questionnaires

Spontaneous somatic mutant frequencies and mutational spectra at the hypoxanthine - guanine phosphoribosyl transferase (hprt) locus in human T- lymphocytes show a strict age dependency from birth to adults (Mut. Res. 1994). To date, no studies have evaluated spontaneous somatic mutant frequencies (MF) in preterm infants. We determined the MF at the hprt locus in preterm infants between 26 and 36 weeks gestation at the time of delivery. A maternal questionnaire, review of the maternal medical record, and determination of plasma cotinine levels were also conducted. History of passive/active cigarette smoke exposure during pregnancy, exposure to medications, and exposure to excessive radiation were evaluated during pregnancy and compared to MF. Infants with known genetic syndromes, major systemic illness or major congenital anomalies were excluded. The cloning efficiency and MF were determined using the hprt T-cell cloning assay, the most widely used assay for determining the frequency and mutational spectra of spontaneous and genotoxic induced somatic genetic mutations in humans. Cord blood samples were obtained from 48 infants, of which 25 were included in the MF analysis. Reasons for non-inclusion were clotted blood (4), insufficient number of cells (6), and no identifiable mutants (13). MF data was obtained from subjects with a mean gestational age of 31.8 weeks. No significant radiation exposure or exposure to genotoxic medications were reported. Medication exposure during pregnancy consisted of, terbutaline, magnesium sulfate, and betamethasone. There were 4 mothers with a history of active/passive cigarette smoke exposure based on questionnaire data. The mean MF for all subjects was 3.44 x l0-6 + 0.44 x l0-6 which is significantly higher than the mean MF in term infants, 1.18 x 10-6 + 0.07 x 10-6. The elevation in mean MF in preterm infants does not appear to be the result of maternal exposures. The MF data obtained demonstrates premature infants have a higher MF than term infants. The elevation in MF may reflect an increase in mutations in rapidly dividing lymphoid cells that subsequently undergo apoptosis prior to 38 weeks gestation. These observations suggest that lymphoid cells in the developing fetus may be at a higher risk of obtaining somatic mutations spontaneously or as a result of genotoxic exposure.

自发体细胞突变频率和突变谱 人 T- 中的次黄嘌呤 - 鸟嘌呤磷酸核糖转移酶 (hprt) 位点 淋巴细胞从出生到成年表现出严格的年龄依赖性（Mut. Res. 1994）。迄今为止，还没有研究评估自发体细胞突变 早产儿的频率（MF）。我们确定了 hprt 处的 MF 妊娠 26 至 36 周之间的早产儿的位点 送货。产妇调查问卷、产妇病历审查、 还进行了血浆可替宁水平的测定。历史 怀孕期间被动/主动接触香烟烟雾、接触 期间对药物治疗和过度辐射暴露进行了评估 怀孕并与 MF 相比。患有已知遗传综合征的婴儿，主要 排除全身性疾病或重大先天异常。克隆 使用 hprt T 细胞克隆测定法测定效率和 MF， 用于确定频率和突变的最广泛使用的测定法 自发和遗传毒性诱导的体细胞基因突变谱 人类。采集了 48 名婴儿的脐带血样本，其中 25 名是 包含在 MF 分析中。未纳入的原因是凝血 (4)，细胞数量不足(6)，并且没有可识别的突变体(13)。 MF 数据取自平均孕龄为 31.8 岁的受试者 几周。没有明显的辐射暴露或遗传毒性暴露 报告了药物治疗。怀孕期间的药物暴露包括 特布他林、硫酸镁和倍他米松。有 4 个 有主动/被动吸烟史的母亲基于 问卷数据。所有受试者的平均 MF 为 3.44 x l0-6 + 0.44 x l0-6 显着高于足月儿的平均 MF 1.18 x 10-6 + 0.07 x 10-6。早产儿平均 MF 的升高并不 似乎是母亲接触的结果。 获得的MF数据 表明早产儿的 MF 高于足月儿。这 MF 的升高可能反映了快速分裂中突变的增加 随后在 38 周之前发生凋亡的淋巴细胞 妊娠。 这些观察结果表明，淋巴样细胞 发育中的胎儿获得体细胞突变的风险可能更高 自发地或由于遗传毒性暴露而发生。