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Featured researches published by D.T. Carrell.


The Journal of Clinical Endocrinology and Metabolism | 2009

Effect of Roux-en-Y Gastric Bypass Surgery on the Sex Steroids and Quality of Life in Obese Men

Ahmad O. Hammoud; Mark Gibson; Steven C. Hunt; Ted D. Adams; D.T. Carrell; Ronette L. Kolotkin; A. Wayne Meikle

CONTEXT The effect of bariatric surgery on the reproductive function of obese men is not entirely elucidated. OBJECTIVE The aim of the study was to define the effect of Roux-En-Y gastric bypass surgery on the reproductive hormones and sexual function in obese men. DESIGN AND SETTING The cohort was followed for 2 yr at a clinical research center. PATIENTS Sixty-four severely obese men (22 who had gastric bypass surgery and 42 controls) participated in the study. INTERVENTION(S) Anthropometrics [weight, body mass index (BMI), and percentage body fat] and reproductive hormones were measured. The sexual quality of life was assessed using the Impact of Weight on the Quality Of Life-Lite questionnaire. MAIN OUTCOME MEASURE(S) Reproductive hormones and sexual quality of life were measured. RESULTS The mean age was 48.9 +/- 1.2 yr. At baseline, mean weight was 333.0 +/- 7.1 lb, BMI was 46.2 +/- 0.9 kg/m(2), and total testosterone was 339.9 +/- 21.32 ng/dl. BMI correlated positively with estradiol and negatively with total and free testosterone. Indices of dissatisfaction with sexual quality of life correlated positively with measures of obesity. Difficult sexual performance and low sexual desire correlated negatively with free and total testosterone (r = -0.273, P = 0.038; and r = -0.267, P = 0.042, respectively). After 2 yr, the gastric bypass surgery group had a significant decrease in BMI (-16.6 +/- 1.2 vs. -0.46 +/- 0.51 kg/m(2)) and estradiol (-8.1 +/- 2.4 vs. 1.6 +/- 1.4 pg/ml) and had an increase in total testosterone (310.8 +/- 47.6 vs. 14.2 +/- 15.3 ng/dl) and free testosterone (45.2 +/- 5.1 vs. -0.4 +/- 3.0 pg/ml). Sexual quality of life was improved after gastric bypass surgery. CONCLUSION Hormonal alterations and diminished sexual quality of life among obese men are related to degree of obesity, and both are improved after gastric bypass surgery.


Fertility and Sterility | 1994

Ovulation induction with gonadotropins and intrauterine insemination compared with in vitro fertilization and no therapy: a prospective, nonrandomized, cohort study and meta-analysis *

C.M. Peterson; Harry H. Hatasaka; Kirtly Parker Jones; Poulson Am; D.T. Carrell; Ronald L. Urry

OBJECTIVES To determine whether one to four cycles of ovulation induction with hMG and IUI or one cycle of IVF results in the highest pregnancy rate and is least expensive and whether published pregnancy rates for one to four cycles of hMG and IUI results in a higher pregnancy rate than rates for one cycle of IVF, zygote intrafallopian transfer (ZIFT), or GIFT. DESIGN Prospective, nonrandomized, cohort study. Patients were excluded who were infertile for < 18 months, had a significant male factor, had greater than mild endometriosis, or had bilateral nonpatency of the fallopian tubes. Cohort groups included 47 hMG and IUI patients (99 cycles), 19 IVF patients (19 cycles), and 21 patients (210 cycles) receiving no treatment. A meta-analysis on accumulated hMG and IUI data using similar entry criteria was also performed. Theoretical calculations were performed and stable fecundity assumed to compare with national data on IVF, ZIFT, and GIFT. SETTING Fertility Center, Division of Reproductive Endocrinology, University of Utah, Salt Lake City, Utah. RESULTS A course of therapy with one to four cycles of hMG and IUI was just as effective as one cycle of IVF in achieving pregnancy. No significant difference in pregnancy rates was found between one IVF cycle and one to four cycles of hMG and IUI in our population. In vitro fertilization was more expensive than four cycles of hMG and IUI. Both IVF and hMG and IUI were more effective than no therapy. Published data also suggest that four cycles of hMG and IUI theoretically result in higher pregnancy rates than one cycle of IVF, ZIFT, or GIFT. CONCLUSION Cost-benefit analysis comparing hMG and IUI, IVF, and no therapy in infertility patients may favor a course of four cycles of hMG and IUI as the first line of therapy. Using meta-analysis and theoretical assumptions, the pregnancy rate for one cycle of hMG and IUI is inferior to IVF, GIFT, or ZIFT; two cycles are comparable to IVF or ZIFT and inferior to GIFT; three cycles are superior to IVF or ZIFT and comparable to GIFT; and four cycles are theoretically superior to all techniques.


Human Reproduction | 2014

Comparative analysis of three sperm DNA damage assays and sperm nuclear protein content in couples undergoing assisted reproduction treatment

Luke Simon; Lihua Liu; Kristin Murphy; S. Ge; James M. Hotaling; Kenneth I. Aston; Benjamin R. Emery; D.T. Carrell

STUDY QUESTION Is there an association between sperm DNA damage, measured by three different assays, sperm nuclear protein content and clinical outcomes in assisted reproduction treatment (ART)? SUMMARY ANSWER Sperm DNA damage measured by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling (TUNEL) and the Comet assay were significantly associated with ART outcomes in our single institution study. WHAT IS KNOWN ALREADY Abnormal protamine expression is known to be associated with sperm DNA damage and male infertility. A number of studies have shown a significant relationship between sperm DNA damage and ART outcomes. To date, there are no large studies providing direct comparisons of DNA damage tests within the same study population. Thus, the prognostic value for each method remains unknown. STUDY DESIGN, SIZE, DURATION Cross-sectional study of 238 men from infertile couples undergoing ART at the University Center for Reproductive Medicine, Utah, USA, between April 2011 and March 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS Sperm from men undergoing ART were tested for DNA damage using the alkaline Comet assay, TUNEL and flow cytometric chromatin evaluation (FCCE) assays. Histone retention was analysed using the aniline blue staining method, whereas protamine content (proteins P1 and P2) and ratio were analysed using acid urea gel electrophoresis. The prognostic value of each sperm DNA test to predict clinical pregnancy was calculated. MAIN RESULTS AND THE ROLE OF CHANCE Histone retention was associated with sperm DNA damage (P < 0.001), reduced embryo quality (P = 0.005) and clinical pregnancies (P < 0.001). The mean percentage of sperm with DNA damage was significantly higher in sperm from non-pregnant couples compared with that from pregnant couples, as measured by TUNEL assay (15.04 ± 1.16% versus 8.79 ± 0.56%; P < 0.001) and alkaline Comet assay (72.79 ± 2.49% versus 55.86 ± 2.29%; P < 0.001). There was no association between clinical pregnancies and DNA fragmentation index measured by FCCE (12.97 ± 1.46 versus 14.93 ± 1.65; P = 0.379). Of the protamine parameters analysed, only the P1/P2 ratio was associated with sperm count (P = 0.013), mens age (P = 0.037), maturity (P = 0.049) and blastocyst quality (P = 0.012). Histone retention and sperm DNA damage measured by Comet and TUNEL assays were associated with fertilization rate (P < 0.05), embryo quality (P < 0.05) and implantation rate (P < 0.05). LIMITATIONS, REASONS FOR CAUTION A potential drawback of this study is that it is cross-sectional. Generally in such studies there is more than one variable that could cause the effect. Analysing sperm is one part of the equation; there are also a number of female factors that have the potential to influence ART outcomes. Therefore, given the large and well-established role of female factors in infertility, normal sperm DNA integrity and protamination do not necessarily ensure clinical pregnancy in ART. Thus, female factors can reduce the prognostic value of sperm DNA tests. Further, our use of native semen instead of prepared sperm may have iatrogenically increased the DNA damage. WIDER IMPLICATIONS OF THE FINDINGS Alteration in sperm nuclear protein affects sperm DNA integrity. Further, with the current dataset, TUNEL and Comet assays appeared more predictive of ART success than FCCE. STUDY FUNDING/COMPETING INTEREST(S) No personal or direct financial support has been received for any of this work. The authors declare no competing interests. TRIAL REGISTRATION NUMBER N/A.


Archives of Andrology | 1993

Role of the Cumulus in the Selection of Morphologically Normal Sperm and Induction of the Acrosome Reaction During Human in Vitro Fertilization

D.T. Carrell; Richard G. Middleton; C. M. Peterson; Kirtly Parker Jones; Ronald L. Urry

This study analyzed the role that the cumulus oophorus may play in the selection of morphologically normal sperm and the induction of the acrosome reaction. Using the triple stain technique, sperm morphology and acrosomal status were compared between sperm that penetrated the cumulus during in vitro fertilization and sperm from outside the cumulus. The mean percentage of morphologically normal sperm in the samples was 54 +/- 2.8 and increased (p < 0.05) to 67 +/- 2.6 within the cumulus. Tapered sperm were significantly decreased (p < 0.05) within the cumulus. The percentage of sperm undergoing the acrosome reaction significantly increased (p < 0.05) from 14.5 +/- 1.5 to 24.5 +/- 1.9 when incubated with a cumulus mass, and further increased to 49 +/- 3.3 when incubated with mature, expanded cumulus tissue containing an oocyte. These data indicate that human cumulus oophorus plays an active role in the selection of morphologically normal sperm, and influences the ability of the sperm to undergo the acrosome reaction.


Andrologia | 2009

Protamine ratio and the level of histone retention in sperm selected from a density gradient preparation

Sue Hammoud; Lihua Liu; D.T. Carrell

Fertile males express two forms of sperm nuclear proteins, protamine 1 (P1) and protamine 2 (P2), in roughly equal quantities, whereas some infertile men have been shown to have a reduction in protamine content and an increase in the level of histones retained in mature sperm. In this study, we assessed histone and protamine levels in spermatozoa isolated from different layers of a density gradient centrifugation column to evaluate the nuclear protein content of the sperm population selected. Protamine levels were measured using acid gel electrophoresis and immunofluorescence, and the percentage of cells retaining histones was evaluated using aniline staining and immunofluorescence. Our data suggests that there is an inverse correlation between P1/P2 ratio and the level of histone expression in the different layers of the density gradient. Paradoxically, the 90% layer had a lower P1/P2 ratio, which corresponded with an increase in histone expression. It is concluded that although the sperm population selected in the 90% layer of the density gradient columns had a lower P1/P2 ratio, it was yet similar to the P1/P2 ratio observed in previously screened fertile donors.


Archives of Andrology | 2004

Sperm chromosome aneuploidy as related to male factor infertility and some ultrastructure defects.

D.T. Carrell; Benjamin R. Emery; Aaron L. Wilcox; B Campbell; Lisa Erickson; Harry H. Hatasaka; Kirtly Parker Jones; C.M. Peterson

Some men have elevated levels of sperm chromosome aneuploidy. In this study, we have evaluated and summarized sperm aneuploidy rates in male infertility patients and control groups. The mean aneuploidy rate for five chromosomes (X, Y, 13, 18, 21) was 1.2 ± 0.1 for fertile controls, 1.4 ± 0.1 for a general population control group, and 5.8 ± 1.14 for the patients. When the patients were classified by the type of male factor infertility, the total aneuploidy rate was 2.6 ± 0.3 in men with moderately diminished semen quality (n = 7), 4.0 ± 0.3 patients with severe teratoasthenooligozoospermia, and 15.9 ± 3.8 for men with rare ultrastructure defects such as round head only syndrome or severe tail agenesis. Some infertility patients have a severely elevated level of sperm chromosome aneuploidy, which may contribute to infertility or diminish the likelihood of a successful outcome from IVF/ICSI. The severity of sperm chromosome aneuploidy appears to be proportional to the severity of abnormal semen quality: in particular, abnormal morphology. The high rates of aneuploidy in patients with severe ultrastructure defects suggest that caution should be employed in counseling those patients prior to IVF/ICSI.


Journal of Andrology | 2016

Teratozoospermia and asthenozoospermia are associated with specific epigenetic signatures.

Timothy G. Jenkins; Kenneth I. Aston; J.M. Hotaling; Monis B. Shamsi; Luke Simon; D.T. Carrell

Semen analysis is commonly used as a tool to assess the fertility potential of a male, despite its relatively low predictive power. In this study, we have assessed associations between semen analysis findings (low count, low motility, low viability, poor sperm penetration assay results, poor morphology, and increased DNA damage) and DNA methylation patterns in mature spermatozoa. DNA methylation patterns in the mature spermatozoa are thought to be indicative of patterns in the adult germline stem cells and may offer insight into potential perturbations to cellular pathways involved in spermatogenesis. In this study, sperm DNA methylation at >480,000 CpGs was assessed in 94 men using the Illumina 450k HumanMethylation Array and compared to standard measures of sperm quality. We did not identify any global changes to methylation profiles that were associated with reduced semen parameters. Similarly, we found no significant difference in methylation variability that was associated with any abnormal semen analysis parameter, although sperm displaying abnormal parameters tended to have an increased coefficient of variability, suggesting that, in some samples, this may be a contributing factor. Analysis of methylation at single CpGs and genomic regions did identify associations for low viability and low motility, and to a smaller extent, low count. Interestingly, based on GO Term analysis, differentially methylated regions associated with low viability were over‐represented in regions important in meiosis, spermatogenesis, and genomic imprinting. These results suggest that while there are not global alterations to the sperm methylome associated with semen abnormalites, some viability associated regional alterations do exist that may be indicative of perturbed cellular pathways during spermatogenesis.


Journal of Andrology | 2017

Cigarette smoking significantly alters sperm DNA methylation patterns

Timothy G. Jenkins; E. R. James; D. F. Alonso; J. R. Hoidal; Patrick J. Murphy; James M. Hotaling; Bradley R. Cairns; D.T. Carrell; Kenneth I. Aston

Numerous health consequences of tobacco smoke exposure have been characterized, and the effects of smoking on traditional measures of male fertility are well described. However, a growing body of data indicates that pre‐conception paternal smoking also confers increased risk for a number of morbidities on offspring. The mechanism for this increased risk has not been elucidated, but it is likely mediated, at least in part, through epigenetic modifications transmitted through spermatozoa. In this study, we investigated the impact of cigarette smoke exposure on sperm DNA methylation patterns in 78 men who smoke and 78 never‐smokers using the Infinium Human Methylation 450 beadchip. We investigated two models of DNA methylation alterations: (i) consistently altered methylation at specific CpGs or within specific genomic regions and (ii) stochastic DNA methylation alterations manifest as increased variability in genome‐wide methylation patterns in men who smoke. We identified 141 significantly differentially methylated CpGs associated with smoking. In addition, we identified a trend toward increased variance in methylation patterns genome‐wide in sperm DNA from men who smoke compared with never‐smokers. These findings of widespread DNA methylation alterations are consistent with the broad range of offspring heath disparities associated with pre‐conception paternal smoke exposure and warrant further investigation to identify the specific mechanism by which sperm DNA methylation perturbation confers risk to offspring health and whether these changes can be transmitted to offspring and transgenerationally.


Andrologia | 2009

Effect of fluctuations in temperature encountered during handling and shipment of human cryopreserved semen

D.T. Carrell; A. L. Wilcox; R. L. Urry

Summary. The effect of temperature fluctuations which cryopreserved spermatozoa may undergo during routine shipping and handling was evaluated in sperm frozen with two cryoprotectants. Sperm frozen in TEST‐yolk buffer maintained motility better than those frozen in glycerol solution in all studies. Sperm motility was significantly compromised in samples stored more than one day in dry ice, regardless of the cryoprotectant, and more than two days in a liquid nitrogen shipping dewar if frozen in glycerol solution. Sperm motility was not compromised following exposure to room temperature for up to 3 min if TEST‐yolk buffer was used as the cryoprotectant, but was compromised following 1 min exposure using glycerol cryoprotectant. This study describes the limits of non‐ideal conditions that spermatozoa may undergo during shipping and handling, and demonstrates the effects of the cryoprotectant on those limits.


Andrologia | 2017

Sperm DNA damage output parameters measured by the alkaline Comet assay and their importance.

Luke Simon; Kenneth I. Aston; Benjamin R. Emery; J.M. Hotaling; D.T. Carrell

The alkaline Comet assay has shown high diagnostic value to determine male reproductive health and prognostic ability to predict ART success. Here, spermatozoon was analysed in 47 fertile donors and 238 patients, including 132 couples undergoing ART [semen was collected: Group I – within 3 months of their treatment (n = 79); and Group II – 3 months prior to their treatment (n = 53)]. We introduce four Comet distribution plots (A, B1, B2 and C) by plotting the level of DNA damage (x‐axis) and percentage of comets (y‐axis). Fertile donors had low mean DNA damage, olive tail moment and per cent of spermatozoa with damage and increased type A plots. Comet parameters were associated with clinical pregnancies in Group I. About 66% of couples with type A distribution plot were successful after ART, whereas couples with type B1, B2 and C distribution plots achieved 56%, 44% and 33% pregnancies respectively. The efficiency of the Comet assay was due to complete decondensation process, where the compact sperm nuclear DNA (28.2 ± 0.2 μm3) is decondensed to ~63 μm3 (before lysis) and ~1018 μm3 (after lysis). A combinational analysis of all the Comet output parameters may provide a comprehensive evaluation of patients reproductive health as these parameters measure different aspects of DNA damage within the spermatozoa.

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