Chris M. Thomas

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BACKGROUND Thiols are scavengers of reactive oxygen species (ROS). We aim to investigate associations between thiols in various fluids in (sub)fertile couples and fertility outcome parameters. METHODS In 156 couples undergoing assisted reproduction techniques (ART), we measured the concentrations of glutathione (GSH), cysteine (Cys), homocysteine (Hcy)(More)
Current treatments of subfertile couples are usually empiric, as the true cause of subfertility often remains unknown. Therefore, we outline the role of nutritional and biochemical factors in reproduction and subfertility. A literature search was performed using MEDLINE, Science Direct and bibliographies of published work with both positive and negative(More)
OBJECTIVE To establish the prevalence of hyperhomocysteinemia in women with unexplained recurrent early pregnancy loss. DESIGN In a patient-control study, the methionine-homocysteine metabolism was investigated by a standardized oral methionine-loading test. SETTING Gynecologic outpatient department of university hospital. PATIENTS One-hundred and two(More)
In this study, the semen analysis results of a fertile population were compared with those from a subfertile population, in order to establish normal cut-off values for the standard semen parameters with the aid of receiver operating characteristic (ROC) curve analysis. The fertile group comprised healthy males (n = 107) without any history of fertility(More)
Fragile X premutations are known to be a risk factor for diminished ovarian function at a relatively young age. We studied endocrine profiles of female fragile X family members (n = 79) at risk of premature ovarian failure (POF). Of these 79 women aged <40 years, 45 had menstrual cycles, and 34 were using oral contraceptives. Of the women with menstrual(More)
Some pesticides may interfere with the female hormonal function, which may lead to negative effects on the reproductive system through disruption of the hormonal balance necessary for proper functioning. Previous studies primarily focused on interference with the estrogen and/or androgen receptor, but the hormonal function may be disrupted in many more ways(More)
To determine the effects of daily supplementation of 0.5 mg folic acid on homocysteine and folate concentrations, we investigated 49 women with a history of unexplained recurrent miscarriages. A methionine loading test (including the vitamin concentrations of concern) was used preceding and after 2 mo of folic acid intake. Subsequently, these effects were(More)
BACKGROUND Vitamin status, methylenentetrahydrofolate reductase (MTHFR) genotype, age, sex, and lifestyle factors are all predictors of total homocysteine (tHcy) concentrations in adults. Limited data are available about the influence of these factors on tHcy in children. OBJECTIVE The objective was to describe tHcy and its predictors in Dutch children.(More)
BACKGROUND An elevated plasma total homocysteine concentration is a risk factor for cardiovascular disease and neural tube defects. A high daily intake of supplemental folic acid is known to decrease total homocysteine concentrations. OBJECTIVE We studied the effect of low-dose folic acid administration (250 or 500 (microgram/d) for 4 wk on plasma total(More)
Elevated total plasma homocysteine (tHcy) concentrations are considered a risk factor for neural tube defects (NTD) and cardiovascular disease. Supplementation with folic acid decreases the risk of women having children with NTD. In both sexes, it decreases tHcy levels. We investigated the efficacy of natural dietary folate in improving folate and(More)