Rebecca Z Sokol

University of Southern California, Los Angeles, CA, United States

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Publications (31)103.58 Total impact

  • Rebecca Z Sokol
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    ABSTRACT: Important medical conditions associated with Klinefelter syndrome (KS) are categorized as: 1) motor, cognitive, and behavioral dysfunction; 2) tumors; 3) vascular disease; and 4) endocrine/metabolic and autoimmune diseases. Earlier diagnosis of KS may lead to earlier intervention with effective treatment.
    Fertility and sterility 06/2012; 98(2):261-5. · 3.97 Impact Factor
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    ABSTRACT: To assess reliability of a high-throughput assay of sperm DNA methylation. Observational study comparing DNA methylation of sperm isolated from 3 divided and 12 longitudinally collected semen samples. Academic medical center. One man undergoing screening semen analysis during evaluation of an infertile couple and 2 healthy fertile male volunteers. Spermatozoa were separated from seminal plasma and somatic cells using gradient separation. DNA was extracted from spermatozoa, and DNA methylation was assessed at 1,505 DNA sequence-specific sites. Repeatability of sperm DNA methylation measures, estimated by correlation coefficients. DNA methylation levels were highly correlated within matched sets of divided samples (all r ≥ 0.97) and longitudinal samples (average r = 0.97). The described methodology reliably assessed methylation of sperm DNA at large numbers of sites. Methylation profiles were consistent over time. High-throughput assessment of sperm DNA methylation is a promising tool for studying the role of epigenetic state in male fertility.
    Fertility and sterility 12/2011; 96(6):1325-30. · 3.97 Impact Factor
  • Rebecca Z. Sokol, Donna Shoupe
    Management of Common Problems in Obstetrics and Gynecology, Fifth Edition, 07/2010: pages 404 - 410; , ISBN: 9781444323030
  • Rebecca Z. Sokol
    Management of Common Problems in Obstetrics and Gynecology, Fifth Edition, 07/2010: pages 438 - 441; , ISBN: 9781444323030
  • Rebecca Z Sokol
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    ABSTRACT: A normal functioning reproductive endocrine system is a prerequisite for normal male fertility. Any disruption of the delicately coordinated interaction between the components of the hypothalamic-pituitary-testicular axis may lead to hypogonadism and/or infertility. The goal of the clinical evaluation is to determine if the patient has an abnormality of testosterone production or action, the etiology of the abnormality, and if hormone therapy will correct the infertility. Based on a careful history, physical examination, and evaluation of the hormones of the reproductive axis, the physician will ascertain if the patient's hypogonadism is (1) prepubertal or postpubertal in onset; (2) the result of an abnormality in the hypothalamic-pituitary axis, the testes, or the androgen receptor; or (3) associated with another underlying medical condition. This information will place the patient into one of four diagnostic categories: hypogonadotropic hypogonadism, testicular failure, 5alpha-reductase deficiency, or androgen resistance. Within each category are disorders with identifiable pathogenic mechanisms. Recent studies have added to these lists and have provided insights into the molecular basis and inheritance patterns of several of these endocrinopathies.
    Seminars in Reproductive Medicine 04/2009; 27(2):149-58. · 3.21 Impact Factor
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    ABSTRACT: Many studies have investigated the association between male infertility and trinucleotide repeat polymorphisms in the androgen receptor (AR) gene, but no comprehensive meta-analysis of all published studies has been conducted. Our goals were to summarize published data on associations between AR CAG and GGC repeat lengths and male infertility and investigate sources of variation between study results. We searched for reports published before October 2006 using Medline, PubMed, and Web of Science. All selected studies included the following: a case group with infertility as measured by semen parameters, a control group of known or presumed fertile men, and measurement of CAG and/or GGC repeat lengths among cases and controls. Thirty-nine reports were selected based on these criteria, and 33 were ultimately included in the meta-analysis. One investigator extracted data on sample size, mean and sd of trinucleotide repeat length, and study characteristics. Estimates of the standardized mean difference (95% confidence interval) were 0.19 (0.09-0.29) for the 33 studies and 0.31 (0.14-0.47) for a subset of 13 studies that used more stringent case and control selection criteria. Thus, in both groups, cases had statistically significantly longer CAG repeat length than controls. Publication date appeared to be a significant source of variation between studies. This meta-analysis provides support for an association between increased androgen receptor CAG length and idiopathic male infertility, suggesting that even subtle disruptions in the androgen axis may compromise male fertility.
    Journal of Clinical Endocrinology &amp Metabolism 12/2007; 92(11):4319-26. · 6.43 Impact Factor
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    Kiros Berhane, Rebecca Sokol
    Environmental Health Perspectives 04/2007; · 7.26 Impact Factor
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    ABSTRACT: Male-factor infertility is a common condition, and etiology is unknown for a high proportion of cases. Abnormal epigenetic programming of the germline is proposed as a possible mechanism compromising spermatogenesis of some men currently diagnosed with idiopathic infertility. During germ cell maturation and gametogenesis, cells of the germ line undergo extensive epigenetic reprogramming. This process involves widespread erasure of somatic-like patterns of DNA methylation followed by establishment of sex-specific patterns by de novo DNA methylation. Incomplete reprogramming of the male germ line could, in theory, result in both altered sperm DNA methylation and compromised spermatogenesis. We determined concentration, motility and morphology of sperm in semen samples collected by male members of couples attending an infertility clinic. Using MethyLight and Illumina assays we measured methylation of DNA isolated from purified sperm from the same samples. Methylation at numerous sequences was elevated in DNA from poor quality sperm. This is the first report of a broad epigenetic defect associated with abnormal semen parameters. Our results suggest that the underlying mechanism for these epigenetic changes may be improper erasure of DNA methylation during epigenetic reprogramming of the male germ line.
    PLoS ONE 02/2007; 2(12):e1289. · 3.53 Impact Factor
  • Fertility and Sterility - FERT STERIL. 01/2007; 88.
  • Fertility and Sterility - FERT STERIL. 01/2007; 88.
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    ABSTRACT: A higher proportion of nonobstructive than obstructive azoospermia, as well as an increased prevalence of hypogonadotropic hypogonadism were documented in a retrospective study characterizing azoospermia in a population of predominantly Latino, inner-city male partners of infertile couples, as compared to previous reports from relatively affluent socioeconomic status male populations.
    Fertility and sterility 08/2006; 86(1):197-9. · 3.97 Impact Factor
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    ABSTRACT: Idiopathic male infertility may be due to exposure to environmental toxicants that alter spermatogenesis or sperm function. We studied the relationship between air pollutant levels and semen quality over a 2-year period in Los Angeles, California, by analyzing repeated semen samples collected by sperm donors. Semen analysis data derived from 5,134 semen samples from a sperm donor bank were correlated with air pollutant levels (ozone, nitrogen dioxide, carbon monoxide, and particulate matter < 10 microm in aerodynamic diameter) measured 0-9, 10-14, and 70-90 days before semen collection dates in Los Angeles between January 1996 and December 1998. A linear mixed-effects model was used to model average sperm concentration and total motile sperm count for the donation from each subject. Changes were analyzed in relationship to biologically relevant time points during spermatogenesis, 0-9, 10-14, and 70-90 days before the day of semen collection. We estimated temperature and seasonality effects after adjusting for a base model, which included donor's date of birth and age at donation. Forty-eight donors from Los Angeles were included as subjects. Donors were included if they collected repeated semen samples over a 12-month period between January 1996 and December 1998. There was a significant negative correlation between ozone levels at 0-9, 10-14, and 70-90 days before donation and average sperm concentration, which was maintained after correction for donor's birth date, age at donation, temperature, and seasonality (p < 0.01). No other pollutant measures were significantly associated with sperm quality outcomes. Exposure to ambient ozone levels adversely affects semen quality.
    Environmental Health Perspectives 04/2006; 114(3):360-5. · 7.26 Impact Factor
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    ABSTRACT: To describe the clinical symptoms associated with the diagnosis of pituitary gonadotroph adenoma in premenopausal women. Report of three separate cases. University medical center. Three patients: a 31-year-old woman with primary infertility, recurrent adnexal masses, and highly elevated estradiol level; a 30-year-old woman with recurrent multicystic ovaries following multiple cystectomies and transvaginal cyst aspirations, and elevated estradiol level; a 43-year-old woman with bilateral complex cystic adnexal masses and an elevated estradiol level, who underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy for a suspected granulosa cell tumor. Transsphenoidal resection of a pituitary mass. Serum estradiol, FSH, and LH levels; transvaginal ultrasonography of the ovaries; histologic examination of pituitary tumors. Transsphenoidal resection of pituitary adenomas resulted in normalization of serum estradiol and FSH levels and resolution of adnexal masses in two of the women. Pituitary gonadotroph adenoma must be considered in the differential diagnosis in reproductive-aged women presenting with the clinical symptom triad of new onset oligomenorrhea, bilateral cystic adnexal masses, and elevated estradiol and FSH levels with suppressed levels of LH; timely diagnosis may prevent unnecessary and potentially damaging surgical procedures.
    Fertility and sterility 10/2005; 84(3):757. · 3.97 Impact Factor
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    ABSTRACT: To evaluate the signs and symptoms associated with hyperprolactinemia and establish guidelines for a minimal serum PRL level for which pituitary imaging is indicated. Retrospective study. Reproductive endocrinology clinic in a university hospital. One hundred four consecutive patients with hyperprolactinemia, mean age 30 +/- 6.5 (range 19-44) years. Classification of clinical symptoms, serum hormone measurements, and pituitary magnetic resonance imaging (MRI). Incidence of presenting symptoms, serum PRL levels, and pituitary tumor size. Median (range) PRL value was 82.6 ng/mL (25-1,342). Reported symptoms from most to least common were infertility (48%), headaches (39%), oligoamenorrhea (29%), galactorrhea (24%), and visual changes (13%). Hypothyroidism was diagnosed in 2 of 104 (1.9%) patients. Of 86 patients who had pituitary imaging, 23 (26%) had normal findings and 63 (74%) had pituitary tumor; of these, 47 (55% of total imaged) had microadenomas and 16 (19% of total imaged) had macroadenomas. There was a statistically significant association between the tumor size and the PRL level. However, 11% of the patients with microadenomas had PRL levels >200 ng/mL, and 44% of the patients with macroadenomas had PRL levels between 25 and 200 ng/mL. The most common symptoms in the population studied were infertility and headaches. Coexisting thyroid disease was an uncommon finding. Most patients had a pituitary tumor on MRI. Although tumor size correlated with the serum PRL level, some macroadenomas were detected in women with only moderately elevated PRL values. On the basis of these findings, pituitary imaging should be obtained to identify pituitary tumors in all patients with persistently elevated PRL levels.
    Fertility and sterility 08/2005; 84(1):181-5. · 3.97 Impact Factor
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    ABSTRACT: To determine the effects of dehydroepiandrosterone (DHEA) supplementation on the pharmacokinetics of DHEA and its metabolites and the reproductive axis of healthy young men. A prospective, randomized, double-blind, placebo-controlled pharmacokinetic study. General Clinical Research Center and laboratories at the Keck School of Medicine of the University of Southern California, Los Angeles, California. Fourteen healthy men, ages 18-42 years. Daily oral administration of placebo (n = 5), 50 mg DHEA (n = 4), or 200 mg DHEA (n = 5) for 6 months. Blood samples were collected at frequent intervals on day 1 and at months 3 and 6 of treatment. Quantification of DHEA, DHEA sulfate (DHEAS), androstenedione, T, E(2), dihydrotestosterone (DHT), and 5alpha-androstane-3alpha-17beta-diol glucuronide (ADG). Physical examination, semen analysis, serum LH, FSH, prostate-specific antigen, and general chemistries were carried out. Baseline DHEA, DHEAS, and ADG levels increased significantly from day 1 to months 3 and 6 in the DHEA treatment groups but not in the placebo group. No significant changes were observed in pharmacokinetic values. Clinical parameters were not affected. DHEA, DHEAS, and ADG increased significantly during 6 months of daily DHEA supplementation. Although the pharmacokinetics of DHEA and its metabolites are not altered, sustained baseline elevation of ADG, a distal DHT metabolite, raises concerns about the potential negative impact of DHEA supplementation on the prostate gland.
    Fertility and Sterility 04/2004; 81(3):595-604. · 4.17 Impact Factor
  • Fertility and Sterility 01/2003; 79:8-8. · 4.17 Impact Factor
  • Fertility and Sterility 01/2003; 79:6-6. · 4.17 Impact Factor
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    ABSTRACT: Bladder exstrophy is an uncommon anomaly rarely associated with uterus didelphys. Fertility is limited by associated vaginal malformations, which have traditionally required surgical reconstruction. A woman with a history of bladder exstrophy and hypoplastic vagina presented complaining of painful intercourse. The patient underwent vaginal dilator treatment after corrective surgery for the bladder defect. Without any further fertility therapy she subsequently conceived twins, with one implantation in each horn of a didelphic uterus. Bladder exstrophy, uterus didelphys, and vaginal hypoplasia share a common embryological devel-opment, and the finding of one anomaly can alert to the presence of another. Vaginal dilators may be used in place of surgical reconstruction to allow conception.
    Obstetrics and Gynecology 12/2002; 100(5 Pt 2):1138-41. · 4.80 Impact Factor
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    ABSTRACT: Lead is a male reproductive toxicant. Data suggest that rats dosed with relatively high levels of lead acetate for short periods of time induced changes in the hypothalamic gonadotropin-releasing hormone (GnRH) at the molecular level, but these changes were attenuated with increased concentration of exposure. The current study evaluated whether exposure to low levels of lead acetate over longer periods of time would produce a similar pattern of adaptation to toxicity at the molecular and biologic levels. Adult 100-day-old Sprague-Dawley male rats were dosed with 0, 0.025, 0.05, 0.1, and 0.3% lead acetate in water. Animals were killed after 1, 4, 8, and 16 weeks of treatment. Luteinzing hormone (LH) and GnRH levels were measured in serum, and lead levels were quantified in whole blood. Hypothalamic GnRH mRNA levels were also quantified. We found no significant differences in serum LH and GnRH among the groups of animals treated within each time period. A significant dose-related increase of GnRH mRNA concentrations with lead dosing occurred in animals treated for 1 week. Animals treated for more than 1 week also exhibited a significant increase in GnRH mRNA, but with an attenuation of the increase at the higher concentrations of lead with increased duration of exposure. We conclude that the signals within and between the hypothalamus and pituitary gland appear to be disrupted by long-term, low-dose lead exposure.
    Environmental Health Perspectives 10/2002; 110(9):871-4. · 7.26 Impact Factor
  • Fertility and Sterility 01/2002; 77. · 4.17 Impact Factor

Publication Stats

384 Citations
103.58 Total Impact Points

Institutions

  • 1998–2012
    • University of Southern California
      • • Department of Obstetrics and Gynecology
      • • Department of Preventive Medicine
      Los Angeles, CA, United States
  • 2000–2005
    • University of California, Los Angeles
      • Department of Obstetrics and Gynecology
      Los Angeles, CA, United States
    • Children's Hospital Los Angeles
      Los Angeles, California, United States