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Toth, Thomas

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Toth

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Thomas

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Toth, Thomas
Author's Publications: search.filters.isAuthorOfPublication.c413eabe-6e9e-404a-ad01-757ed8158ae8

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Now showing 1 - 4 of 4
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    Predehydration and Ice Seeding in the Presence of Trehalose Enable Cell Cryopreservation
    (American Chemical Society, 2017) Huang, Haishui; Zhao, Gang; Zhang, Yuntian; Xu, Jiangsheng; Toth, Thomas; He, Xiaoming
    Conventional approaches for cell cryopreservation require the use of toxic membrane-penetrating cryoprotective agents (pCPA), which limits the clinical application of cryopreserved cells. Here, we show intentionally induced ice formation at a high subzero temperature (> −10 °C) during cryopreservation, which is often referred to as ice seeding, could result in significant cell injury in the absence of any pCPA. This issue can be mitigated by predehydrating cells using extracellular trehalose to their minimal volume with minimized osmotically active water before ice seeding. We further observe that ice seeding can minimize the interfacial free energy that drives the devastating ice recrystallization-induced cell injury during warming cryopreserved samples. Indeed, by combining predehydration using extracellular trehalose with ice seeding at high subzero temperatures, high cell viability or recovery is achieved for fibroblasts, adult stem cells, and red blood cells after cryopreservation without using any pCPA. The pCPA-free technology developed in this study may greatly facilitate the long-term storage and ready availability of living cells, tissues, and organs that are of high demand by modern cell-based medicine.
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    Paternal Urinary Concentrations of Parabens and Other Phenols in Relation to Reproductive Outcomes among Couples from a Fertility Clinic
    (NLM-Export, 2015) Dodge, Laura E.; Williams, Paige; Williams, Michelle A.; Missmer, Stacey; Toth, Thomas; Calafat, Antonia M.; Hauser, Russ
    Background: Human exposure to phenols, including bisphenol A and parabens, is widespread. Evidence suggests that paternal exposure to environmental chemicals may adversely affect reproductive outcomes. Objectives: We evaluated associations of paternal phenol urinary concentrations with fertilization rate, embryo quality, implantation, and live birth. Methods: Male–female couples who underwent in vitro fertilization (IVF) and/or intrauterine insemination (IUI) cycles in a prospective study of environmental determinants of fertility and pregnancy outcomes were included. The geometric mean of males’ specific gravity–adjusted urinary phenol concentrations measured before females’ cycle was quantified. Associations between male urinary phenol concentrations and fertilization rate, embryo quality, implantation, and live birth were investigated using generalized linear mixed models to account for multiple cycles per couple. Results: Couples (n = 218) underwent 195 IUI and 211 IVF cycles. Paternal phenol concentrations were not associated with fertilization or live birth following IVF. In adjusted models, compared with the lowest quartile of methyl paraben, paternal concentrations in the second quartile were associated with decreased odds of live birth following IUI (adjusted odds ratio = 0.19; 95% CI: 0.04, 0.82). Conclusions: To our knowledge, these are some of the first data on the association of paternal urinary phenol concentrations with reproduction and pregnancy outcomes. Although these results do not preclude possible adverse effects of paternal paraben exposures on such outcomes, given the modest sample size, further understanding could result from confirmation using a larger and more diverse population. Citation Dodge LE, Williams PL, Williams MA, Missmer SA, Toth TL, Calafat AM, Hauser R. 2015. Paternal urinary concentrations of parabens and other phenols in relation to reproductive outcomes among couples from a fertility clinic. Environ Health Perspect 123:665–671; http://dx.doi.org/10.1289/ehp.1408605
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    Discrete survival model analysis of a couple’s smoking pattern and outcomes of assisted reproduction
    (2017) Vanegas, Jose C.; Chavarro, Jorge; Williams, Paige; Ford, Jennifer; Toth, Thomas; Hauser, Russ; Gaskins, Audrey
    Background: Cigarette smoking has been associated with worse infertility treatment outcomes, yet some studies have found null or inconsistent results. Methods: We followed 225 couples who underwent 354 fresh non-donor assisted reproductive technology (ART) cycles between 2006 and 2014. Smoking history was self-reported at study entry. We evaluated the associations between smoking patterns and ART success using multivariable discrete time Cox proportional hazards models with six time periods: cycle initiation to egg retrieval, retrieval to fertilization, fertilization to embryo transfer (ET), ET to implantation, implantation to clinical pregnancy, and clinical pregnancy to live birth to estimate hazard ratios (HR) and 95% CIs. Time-dependent interactions between smoking intensity and ART time period were used to identify vulnerable periods. Results: Overall, 26% of women and 32% of men reported ever smoking. The HR of failing in the ART cycle without attaining live birth for male and female ever smokers was elevated, but non-significant, compared to never smokers regardless of intensity (HR = 1.02 and 1.30, respectively). Female ever smokers were more likely to fail prior to oocyte retrieval (HR: 3.37; 95% CI: 1.00, 12.73). Every one cigarette/day increase in smoking intensity for females was associated with a HR of 1.02 of failing ART (95% CI: 0.97, 1.08), regardless of duration or current smoking status. Women with higher smoking intensities were most likely to fail a cycle prior to oocyte retrieval (HR: 1.07; 95% CI: 1.00, 1.16). Among past smokers, every additional year since a man had quit smoking reduced the risk of failing ART by 4% (HR: 0.96; 95% CI: 0.91, 1.00) particularly between clinical pregnancy and live birth (HR: 0.86; 95% CI: 0.76, 0.96). Conclusions: Female smoking intensity, regardless of current smoking status, is positively associated with the risk of failing ART cycles between initiation and oocyte retrieval. In men who ever smoked, smoking cessation may reduce the probability of failing ART, particularly between clinical pregnancy and live birth. Trial registration NCT00011713. Registered: 27 February 2001.
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    Urinary Concentrations of Organophosphate Flame Retardant Metabolites and Pregnancy Outcomes among Women Undergoing in Vitro Fertilization
    (Environmental Health Perspectives, 2017) Carignan, Courtney C.; Mínguez-Alarcón, Lidia; Butt, Craig M.; Williams, Paige; Meeker, John D.; Stapleton, Heather M.; Toth, Thomas; Ford, Jennifer; Hauser, Russ
    Background: Evidence from animal studies suggests that exposure to organophosphate flame retardants (PFRs) can disrupt endocrine function and impair embryo development. However, no epidemiologic studies have been conducted to evaluate effects on fertility and pregnancy outcomes. Objectives: We evaluated associations between urinary concentrations of PFR metabolites and outcomes of in vitro fertilization (IVF) treatment among couples recruited from an academic fertility clinic. Methods: This analysis included 211 women enrolled in the Environment And Reproductive Health (EARTH) prospective cohort study (2005–2015) who provided one or two urine samples per IVF cycle. We measured five urinary PFR metabolites [bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPHP), isopropylphenyl phenyl phosphate (ip-PPP), tert-butylphenyl phenyl phosphate (tb-PPP), and bis(1-chloro-2-propyl) phosphate (BCIPP)] using negative electrospray ionization liquid chromatography tandem mass spectrometry (LC-MS/MS). Molar concentrations of the urinary PFR metabolites were summed. We used multivariable generalized linear mixed models to evaluate the association of the PFR metabolites with IVF outcomes, accounting for multiple IVF cycles per woman. Results: Detection frequencies were high for BDCIPP (87%), DPHP (94%), and ip-PPP (80%), but low for tb-PPP (14%) and BCIPP (0%). We observed decreased success for several IVF outcomes across increasing quartiles of both summed and individual PFR metabolites (DPHP and ip-PPP) in our adjusted multivariable models. Significant declines in adjusted means from the lowest to highest quartile of ΣPFR were observed for the proportion of cycles resulting in successful fertilization (10% decrease), implantation (31%), clinical pregnancy (41%), and live birth (38%). Conclusions: Using IVF to investigate human reproduction and pregnancy outcomes, we found that concentrations of some urinary PFR metabolites were negatively associated with proportions of successful fertilization, implantation, clinical pregnancy, and live birth. https://doi.org/10.1289/EHP1021