Changzhong Chen

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OBJECTIVE To examine rates of conception and pregnancy loss and their relations with time to clinical pregnancy and reproductive outcomes. DESIGN A prospective observational study. SETTING Population-based cohort in China. PATIENT(S) Five hundred eighteen healthy newly married women who intended to conceive. Upon stopping contraception, daily records(More)
CONTEXT Little is known about genetic susceptibility to cigarette smoke in relation to adverse pregnancy outcomes. OBJECTIVE To investigate whether the association between maternal cigarette smoking and infant birth weight differs by polymorphisms of 2 maternal metabolic genes: CYP1A1 and GSTT1. DESIGN, SETTING, AND PARTICIPANTS Case-control study(More)
Previous studies of pregnancy losses and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) were limited because they did not include losses prior to clinical detection of pregnancy and because exposures were measured after the pregnancies of interest. The authors examined the association of preconception serum total DDT (sum of DDT isomers and(More)
Nicotine is the major addictive substance in cigarettes, and genes involved in sensing nicotine are logical candidates for vulnerability to nicotine addiction. We studied six single-nucleotide polymorphisms (SNPs) in the CHRNA4 gene and four SNPs in the CHRNB2 gene with respect to nicotine dependence in a collection of 901 subjects (815 siblings and 86(More)
PIK3CA gain-of-function mutations are a common oncogenic event in human malignancy, making phosphatidylinositol 3-kinase (PI3K) a target for cancer therapy. Despite the promise of targeted therapy, resistance often develops, leading to treatment failure. To elucidate mechanisms of resistance to PI3K-targeted therapy, we constructed a mouse model of breast(More)
Inactivation of the XRCC4 nonhomologous end-joining factor in the mouse germ line leads to embryonic lethality, in association with apoptosis of newly generated, postmitotic neurons. We now show that conditional inactivation of the XRCC4 in nestin-expressing neuronal progenitor cells, although leading to no obvious phenotype in a WT background, leads to(More)
Osteoporosis is a chronic disorder characterized by low bone mass and fragility fractures. It affects more than 25 million men and women in the United States alone. Although several candidate genes, such as the vitamin-D-receptor gene or the estrogen-receptor gene, have been suggested in the pathogenesis of osteoporosis, the genetic dissection of this(More)
The authors investigated whether polymorphisms in two maternal metabolic genes, cytochrome P-450 1A1 (CYP1A1) MspI and epoxide hydrolase 1 (EPHX1) Tyr113His, affect the association of maternal passive smoking with infant birth weight. The study was conducted in a cohort of 1,388 newly married mothers of liveborn singletons who worked in textile mills in(More)
BACKGROUND Human paraoxonase (PON) is an enzyme involved in vasodilation and thrombosis. Disruption of blood blow through the placenta could be part of the pathophysiological mechanism leading to preterm delivery. The purpose of this study was to examine the association between polymorphisms in 2 paraoxonase genes (PON1 and PON2) and preterm delivery. (More)