30 results on '"Nel-Themaat L"'
Search Results
2. Invitro fertilization and andrology laboratory in 2030: expert visions
- Author
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Campbell A, Gardner D, Meseguer M, Miller K, Montag M, Palermo G, Cheung S, Keating D, Xie P, Rosenwaks Z, Rienzi L, Innocenti F, Cimadomo D, Ubaldi F, Sakkas D, Tucker M, Nel-Themaat L, and Simon C
- Abstract
The aim of this article is to gather 9 thought leaders and their team members to present their ideas about the future of invitro fertilization and the andrology laboratory. Although we have seen much progress and innovation in the laboratory over the years, there is still much to come, and this article looks at what these leaders think will be important in the future development of technology and processes in the laboratory. Copyright © 2021 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.
- Published
- 2021
3. Invitro fertilization and andrology laboratories in 2030
- Author
-
Simon C, Campbell A, Gardner D, Meseguer M, Miller K, Montag M, Palermo G, Cheung S, Keating D, Xie P, Rosenwaks Z, Rienzi L, Innocenti F, Cimadomo D, Ubaldi F, Sakkas D, Tucker M, and Nel-Themaat L
- Abstract
The invitro fertilization and andrology laboratories are at the center of assisted reproductive technologies and the place where technicians and embryologists manipulate gametes and preimplantation-stage embryos with the goal of achieving the best embryo for transfer. Through the years, these laboratories have seen developments in technique, technology, and testing. The goal of this Views and Interviews series is to bring together the thought leaders in the field and envision what the laboratories will look like in the next 10 years.
- Published
- 2021
4. 3D genomics across the tree of life reveals condensin II as a determinant of architecture type
- Author
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Hoencamp, C, Dudchenko, O, Elbatsh, AMO, Brahmachari, S, Raaijmakers, JA, van Schaik, T, Cacciatore, AS, Contessoto, VG, van Heesbeen, RGHP, van den Broek, B, Mhaskar, AN, Teunissen, H, St Hilaire, BG, Weisz, D, Omer, AD, Pham, M, Colaric, Z, Yang, Z, Rao, SSP, Mitra, N, Lui, C, Yao, W, Khan, R, Moroz, LL, Kohn, A, St Leger, J, Mena, A, Holcroft, K, Gambetta, MC, Lim, F, Farley, E, Stein, N, Haddad, A, Chauss, D, Mutlu, AS, Wang, MC, Young, ND, Hildebrandt, E, Cheng, HH, Knight, CJ, Burnham, TLU, Hovel, KA, Beel, AJ, Mattei, P-J, Kornberg, RD, Warren, WC, Cary, G, Gomez-Skarmeta, JL, Hinman, V, Lindblad-Toh, K, Di Palma, F, Maeshima, K, Multani, AS, Sen, P, Nel-Themaat, L, Behringer, RR, Kaur, P, Medema, RH, van Steensel, B, de Wit, E, Onuchic, JN, Di Pierro, M, Aiden, EL, Rowland, BD, Hoencamp, C, Dudchenko, O, Elbatsh, AMO, Brahmachari, S, Raaijmakers, JA, van Schaik, T, Cacciatore, AS, Contessoto, VG, van Heesbeen, RGHP, van den Broek, B, Mhaskar, AN, Teunissen, H, St Hilaire, BG, Weisz, D, Omer, AD, Pham, M, Colaric, Z, Yang, Z, Rao, SSP, Mitra, N, Lui, C, Yao, W, Khan, R, Moroz, LL, Kohn, A, St Leger, J, Mena, A, Holcroft, K, Gambetta, MC, Lim, F, Farley, E, Stein, N, Haddad, A, Chauss, D, Mutlu, AS, Wang, MC, Young, ND, Hildebrandt, E, Cheng, HH, Knight, CJ, Burnham, TLU, Hovel, KA, Beel, AJ, Mattei, P-J, Kornberg, RD, Warren, WC, Cary, G, Gomez-Skarmeta, JL, Hinman, V, Lindblad-Toh, K, Di Palma, F, Maeshima, K, Multani, AS, Sen, P, Nel-Themaat, L, Behringer, RR, Kaur, P, Medema, RH, van Steensel, B, de Wit, E, Onuchic, JN, Di Pierro, M, Aiden, EL, and Rowland, BD
- Abstract
We investigated genome folding across the eukaryotic tree of life. We find two types of three-dimensional (3D) genome architectures at the chromosome scale. Each type appears and disappears repeatedly during eukaryotic evolution. The type of genome architecture that an organism exhibits correlates with the absence of condensin II subunits. Moreover, condensin II depletion converts the architecture of the human genome to a state resembling that seen in organisms such as fungi or mosquitoes. In this state, centromeres cluster together at nucleoli, and heterochromatin domains merge. We propose a physical model in which lengthwise compaction of chromosomes by condensin II during mitosis determines chromosome-scale genome architecture, with effects that are retained during the subsequent interphase. This mechanism likely has been conserved since the last common ancestor of all eukaryotes.
- Published
- 2021
5. Decreased levels of follicular fluid saturated fatty acids are associated with diminished ovarian reserve
- Author
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Lin, I.S., primary, Cho, K., additional, Hohos, N.M., additional, Nel-Themaat, L., additional, Rudolph, M.C., additional, and Skaznik-Wikiel, M., additional
- Published
- 2018
- Full Text
- View/download PDF
6. Egg quality and developmental potential from multiple donation cycles in egg bank donors
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Nel-Themaat, L., primary, Chang, C.-C., additional, Bernal, D.P., additional, Kahn, J.M., additional, Shapiro, D.B., additional, and Nagy, Z.P., additional
- Published
- 2011
- Full Text
- View/download PDF
7. Sertoli Cell Behaviors in Developing Testis Cords and Postnatal Seminiferous Tubules of the Mouse
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Nel-Themaat, L., primary, Jang, C.-W., additional, Stewart, M. D., additional, Akiyama, H., additional, Viger, R. S., additional, and Behringer, R. R., additional
- Published
- 2010
- Full Text
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8. Illuminating Testis Morphogenesis in the Mouse
- Author
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Nel-Themaat, L., primary, Gonzalez, G., additional, Akiyama, H., additional, and Behringer, R. R., additional
- Published
- 2009
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9. Isolation, culture and characterisation of somatic cells derived from semen and milk of endangered sheep and eland antelope
- Author
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Nel-Themaat, L., primary, Gómez, M. C., additional, Damiani, P., additional, Wirtu, G., additional, Dresser, B. L., additional, Bondioli, K. R., additional, Lyons, L. A., additional, Pope, C. E., additional, and Godke, R. A., additional
- Published
- 2007
- Full Text
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10. Quality and freezing qualities of first and second ejaculates collected from endangered Gulf Coast Native rams
- Author
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Nel-Themaat, L., primary, Harding, G.D., additional, Chandler, J.E., additional, Chenevert, J.F., additional, Damiani, P., additional, Fernandez, J.M., additional, Humes, P.E., additional, Pope, C.E., additional, and Godke, R.A., additional
- Published
- 2006
- Full Text
- View/download PDF
11. 63 IMPROVEMENT OF SEMEN-DERIVED EPITHELIAL CELL PROLIFERATION BY FIBROBLAST CO-CULTURE
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Nel-Themaat, L., primary, Gómez, M. C., additional, Wirtu, G., additional, Cole, A., additional, Bondioli, K. R., additional, Dresser, B. L., additional, Pope, C. E., additional, and Godke, R. A., additional
- Published
- 2006
- Full Text
- View/download PDF
12. 328 SOMATIC CELL ISOLATION FROM SEMEN BY PERCOLL GRADIENTS
- Author
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Nel-Themaat, L., primary, Gomez, M.C., additional, Wirtu, G., additional, Cole, A., additional, Bondioli, K.R., additional, Dresser, B.L., additional, Godke, R.A., additional, and Pope, C.E., additional
- Published
- 2005
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13. 61ISOLATION AND CULTURE OF SOMATIC CELLS OBTAINED FROM SEMEN AND MILK OF GULF COAST NATIVE SHEEP
- Author
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Nel-Themaat, L., primary, Godke, R.A., additional, Dresser, B.L., additional, and Damiani, P., additional
- Published
- 2004
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- View/download PDF
14. 328 SOMATIC CELL ISOLATION FROM SEMEN BY PERCOLL GRADIENTS
- Author
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Nel-Themaat, L., Gomez, M.C., Wirtu, G., Cole, A., Bondioli, K.R., Dresser, B.L., Godke, R.A., and Pope, C.E.
- Abstract
We previously isolated epithelial-like cells (ELC) from sheep (Ovis aries) and eland (Taurotragus oryx) ejaculates (Nel-Themaat et al. 2004 Reprod. Fertil. Dev. 16, 152). Success rates were low, and the presence of live sperm during initial culture may have altered medium properties, physically prevented contact between cells and the substrate, and/or damaged somatic cell membranes. Using the complete semen sample requires the sacrifice of valuable live spermatozoa without the certainty of obtaining a somatic cell population. Therefore, the purpose of the present study was to develop a method for isolating somatic cells from semen before culture. Separation by discontinuous Percoll gradient centrifugation was performed. Ejaculates obtained by electro-ejaculation from two Louisiana Native rams and rectal massage of one eland bull were washed, layered on columns of 2.5 mL each of 20% (P-20), 50% (P-50), and 90% (P-90) Percoll in 15-mL conical tubes, and centrifuged for 20 min at 400g. Bands were obtained at the three interfaces, as well as a pellet in the P-90 fraction. Each Percoll layer plus the interface band immediately below it was collected by aspiration. Cells from each fraction were re-suspended in serum-supplemented Minimum Essential Medium Alpha containing 500 IU/mL of penicillin, 0.5 mg/mL of streptomycin and 250 g/mL of gentamycin, and were plated on collagen-1 coated dishes. Trypan blue staining was used to determine cell viability in each fraction. After 24 h, dishes were washed and the culture continued until cells attached and proliferated. For both species, the surface fraction yielded primarily dead ELC that were morphologically flat and angular in shape. In the P-20 band, more viable cells were isolated compared with other fractions, although dead cells were also present. In the P-50 and P-90 fractions, few ELC were observed compared with the surface and P-20 fractions. A negligible number of sperm was observed in the surface and P-20 fractions. In contrast, mostly dead sperm were found at the P-50 and P-90 interface band, whereas live spermatozoa were detected in the P-90 pellet. Epithelial-like cells isolated from semen of both species attached (A, initial 24 h of culture), divided (D, within 3 days after plating), and proliferated (P, after 1 week of culture) (see Table). Ram ELC derived from the surface and from the P-20 and P-50 layers attached, but proliferation was detected only with cells collected in the P-20 fraction. In contrast, eland cells collected from the surface and P-20 layers readily attached and proliferated. In summary, a technique has been developed for the isolation of somatic cells from semen using a three-layer Percoll gradient. This method also allows the isolation of motile spermatozoa, hich are available for further use.
- Published
- 2004
- Full Text
- View/download PDF
15. 63 IMPROVEMENT OF SEMEN-DERIVED EPITHELIAL CELL PROLIFERATION BY FIBROBLAST CO-CULTURE
- Author
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Nel-Themaat, L., Gómez, M. C., Wirtu, G., Cole, A., Bondioli, K. R., Dresser, B. L., Pope, C. E., and Godke, R. A.
- Abstract
We previously isolated epithelial-like cells (ELC) from sheep (Ovis aries) and eland (Taurotragus oryx) semen (Nel-Themaat et al. 2004 Reprod. Fertil. Dev. 16, 152) and subsequently developed a system to separate ELC before plating (Nel-Themaat et al. 2005 Reprod. Fertil. Dev. 17, 314). Cells attached and proliferated in only 50% and 31% of the attempts, respectively. Therefore, the purposes of the present study were to improve ELC proliferation by co-culture with inactivated 3T3 mouse fibroblasts and to characterize the obtained cells. Semen fractions from two mature Gulf Coast Native rams (n = 20 ejaculates) and one common eland bull (n = 2 ejaculates) were plated on feeder layers (A), on collagen with feeder cell inserts (B), or on collagen alone (C). For B and C, cell attachment and division were assessed; proliferation and passage 1 (P1) confluence were evaluated for A, B, and C. No difference in attachment rates between B (80%) and C (70%) were found for ovine cells, but (P < 0.05) cells divided more times in B (80%) than in C (35%). All colonies in A (60%) and B (70%) reached P1 confluence and no difference was detected between A and B, but less proliferation (10%) and P1 confluence (5%) were observed in C. Therefore, contact between epithelial cells and feeders was not necessary for growth stimulation by the feeder cells. No difference among A, B, and C was detected for eland ELC proliferation (100%), but no P1 confluence was observed in C. Ram cells were subsequently characterized by immunohistochemical detection of keratin and vimentin, as well as morphology. The 3T3 cells cross-reacted with keratin, and characterization was thus performed mainly on morphology and vimentin expression. Distribution of vimentin microfilaments differed between different epithelial morphologies and fibroblasts. Expression in epithelial cells was faint and patchy in confluent colonies and located around cytoplasmic extremities in semi-confluent colonies. In 3T3 cells, expression was very prominent throughout the cytoplasm and around the nucleus. For treatments A and B, 63 and 57%, respectively, were characterized as only epithelial cells; 25 and 36%, respectively, appeared to contain a mixture of epithelial and fibroblast cells; and 13 and 7%, respectively, contained only fibroblast cells. Only one sample was evaluated from treatment C and only keratin was detected in the epithelial-like colony. We conclude that culture of semen-derived ELC is markedly improved by 3T3 fibroblast co-culture. Further research on conditioned media may simplify the system and reduce chances of 3T3 cell contamination.
- Published
- 2005
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16. Blastocoel fluid as an alternative source of DNA for minimally invasive PGT and biomarker of embryo competence.
- Author
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Campos G and Nel-Themaat L
- Subjects
- Humans, Female, Pregnancy, Biomarkers metabolism, Aneuploidy, Genetic Testing methods, Blastocyst metabolism, Preimplantation Diagnosis methods, DNA analysis
- Abstract
The discovery of DNA in blastocoel fluid (BF-DNA) generated new perspectives in the potential development of simpler and safer alternative non-invasive tests in reproductive genetics. Short DNA fragments of apoptotic origin, together with specific expression patterns of pro- and anti-apoptotic genes in the blastocoel fluid of euploid and aneuploid embryos, suggest a self-correction mechanism to preferentially eliminate aneuploid cells, and purge defective and non-viable cells. The correlation of blastocoel fluid content with the genetic status of the whole embryo, and therefore its potential use in minimally invasive preimplantation genetic testing (miPGT), or as an indicator of embryo potential, remains uncertain and needs to be determined. The limited amount and compromised integrity of BF-DNA, with likely apoptotic origination, constrains its amplification, leading to low concordance and reproducibility rates for both aneuploidy screening and monogenic testing. While embryo genotyping constitutes a more ambitious goal, the presence of analysable DNA after amplification in blastocoel fluid may be used as a clinical biomarker of embryo competency to select the most viable embryo(s) for transfer, and potentially improve the implantation rate. Although blastocentesis remains a promising area for future research, several technical and methodological limitations are currently constraining its consideration for clinical practice., (Copyright © 2024 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2024
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- View/download PDF
17. The developmental competence of human metaphase I oocytes with delayed maturation in vitro.
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Moon JH, Zhao Q, Zhang J, Reddy V, Han J, Cheng Y, Zhang N, Dasig J, Nel-Themaat L, Behr B, and Yu B
- Subjects
- Pregnancy, Female, Humans, Male, Retrospective Studies, Metaphase, Semen, Oocytes, Fertilization in Vitro, Abortion, Spontaneous
- Abstract
Objective: To evaluate whether metaphase I (MI) oocytes completing maturation in vitro to metaphase II ("MI-MII oocytes") have similar developmental competence as the sibling metaphase II (MII) oocytes that reached maturity in vivo., Design: Retrospective cohort study., Setting: Academic medical center., Patient(s): A total of 1,124 intracytoplasmic sperm injection (ICSI) cycles from 800 patients at a single academic center between April 2016 and December 2020 with at least 1 MII oocyte immediately after retrieval and at least 1 sibling "MI-MII oocyte" that was retrieved as MI and matured to MII in culture before ICSI were included in the study., Intervention(s): None., Main Outcome Measure(s): A total of 7,865 MII and 2,369 sibling MI-MII oocytes retrieved from the same individuals were compared for the fertilization and blastocyst formation rates. For patients who underwent single euploid blastocyst transfers (n = 406), the clinical pregnancy, spontaneous pregnancy loss, and live birth rates were compared between the 2 groups., Result(s): The fertilization rate was significantly higher in MII oocytes than in delayed matured MI-MII oocytes (75.9% vs. 56.1%). Similarly, the blastocyst formation rate was higher in embryos derived from MII oocytes than in those from MI-MII oocytes (53.8% vs. 23.9%). The percentage of euploid embryos derived from MII oocytes was significantly higher than that of those from MI-MII oocytes (49.2% vs. 34.7%). Paired comparison of sibling oocytes within the same cycle showed higher developmental competence of the MII oocytes than that of MI-MII oocytes. However, the pregnancy, spontaneous pregnancy loss, and live birth rates after a single euploid blastocyst transfer showed no statistically significant difference between the 2 groups (MII vs. MI-MII group, 65.7% vs. 74.1%, 6.4% vs. 5.0%, and 61.5% vs. 70.0%, respectively)., Conclusion(s): Compared with oocytes that matured in vivo and were retrieved as MII, the oocytes that were retrieved as MI and matured to MII in vitro before ICSI showed lower developmental competence, including lower fertilization, blastocyst formation, and euploidy rates. However, euploid blastocysts from either cohort resulted in similar live birth rates, indicating that the MI oocytes with delayed maturation can still be useful even though the overall developmental competence was lower than that of their in vivo matured counterparts., (Copyright © 2022 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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18. Expression and T cell regulatory action of the PD-1 immune checkpoint in the ovary and fallopian tube.
- Author
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Johnson J, Kim SY, Sam PK, Asokan R, Cari EL, Bales ES, Luu TH, Perez L, Kallen AN, Nel-Themaat L, Polotsky AJ, Post MD, Orlicky DJ, Jordan KR, and Bitler BG
- Subjects
- Female, Humans, B7-H1 Antigen metabolism, Carcinogenesis, Ligands, T-Lymphocytes, Fallopian Tubes, Ovary, Programmed Cell Death 1 Receptor metabolism
- Abstract
Problem: Immune cell trafficking and surveillance within the ovary and fallopian tube are thought to impact fertility and also tumorigenesis in those organs. However, little is known of how native cells of the ovary and fallopian tube interact with resident immune cells. Interaction of the Programmed Cell Death Protein-1 (PD-1/PDCD-1/CD279) checkpoint with PD-L1 is associated with downregulated immune response. We have begun to address the question of whether PD-1 ligand or its receptors (PD-L1/-L2) can regulate immune cell function in these tissues of the female reproductive tract., Method of Study: PD-1 and ligand protein expression was evaluated in human ovary and fallopian tube specimens, the latter of which included stages of tubal cell transformation and early tumorigenesis. Ovarian expression analysis included the determination of the proteins in human follicular fluid (HFF) specimens collected during in vitro fertilization procedures. Finally, checkpoint bioactivity of HFF was determined by treatment of separately-isolated human T cells and the measurement of interferon gamma (IFNγ)., Results: We show that membrane bound and soluble variants of PD-1 and ligands are expressed by permanent constituent cell types of the human ovary and fallopian tube, including granulosa cells and oocytes. PD-1 and soluble ligands were present in HFF at bioactive levels that control T cell PD-1 activation and IFNγ production; full-length checkpoint proteins were found to be highly enriched in HFF exosome fractions., Conclusion: The detection of PD-1 checkpoint proteins in the human ovary and fallopian tube suggests that the pathway is involved in immunomodulation during folliculogenesis, the window of ovulation, and subsequent egg and embryo immune-privilege. Immunomodulatory action of receptor and ligands in HFF exosomes is suggestive of an acute checkpoint role during ovulation. This is the first study in the role of PD-1 checkpoint proteins in human tubo-ovarian specimens and the first examination of its potential regulatory action in the contexts of normal and assisted reproduction., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
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- 2023
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- View/download PDF
19. The ART of cryopreservation and its changing landscape.
- Author
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Pomeroy KO, Comizzoli P, Rushing JS, Lersten IL, and Nel-Themaat L
- Subjects
- Cryopreservation trends, Fertility Preservation trends, Germ Cells physiology, Germ Cells transplantation, Humans, Vitrification, Cryopreservation methods, Fertility Preservation methods, Reproductive Techniques, Assisted trends
- Abstract
The purpose of this review is to educate the reader on the role that cryopreservation has played and continues to play in the ever-evolving field of assisted reproductive technologies, specifically in clinical human fertility treatment. We discuss the science behind the cryopreservation methods and investigated some of the major considerations that any clinic or cryobank faces in terms of risks and liabilities, physical challenges that accompany the constantly growing collection of cryopreserved specimens, and what this means on the ethical and legal front. Finally, we take a glimpse in the future to explore what may be on the horizon for the preservation of gametes and reproductive tissues., (Copyright © 2022. Published by Elsevier Inc.)
- Published
- 2022
- Full Text
- View/download PDF
20. In vitro fertilization and andrology laboratory in 2030: expert visions.
- Author
-
Campbell A, Gardner DK, Meseguer M, Miller KA, Montag M, Palermo GD, Cheung S, Keating D, Xie P, Rosenwaks Z, Rienzi L, Innocenti F, Cimadomo D, Ubaldi FM, Sakkas D, Tucker MJ, Nel-Themaat L, and Simon C
- Subjects
- Andrology legislation & jurisprudence, Automation, Laboratory, Clinical Laboratory Services legislation & jurisprudence, Diffusion of Innovation, Female, Fertilization in Vitro legislation & jurisprudence, Forecasting, History, 21st Century, Humans, Infertility diagnosis, Infertility physiopathology, Male, Policy Making, Pregnancy, Reproductive Medicine legislation & jurisprudence, Andrology trends, Clinical Laboratory Services trends, Fertilization in Vitro trends, Infertility therapy, Reproductive Medicine trends
- Abstract
The aim of this article is to gather 9 thought leaders and their team members to present their ideas about the future of in vitro fertilization and the andrology laboratory. Although we have seen much progress and innovation in the laboratory over the years, there is still much to come, and this article looks at what these leaders think will be important in the future development of technology and processes in the laboratory., (Copyright © 2021 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
21. In vitro fertilization and andrology laboratories in 2030.
- Author
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Simon C, Campbell A, Gardner DK, Meseguer M, Miller KA, Montag M, Palermo GD, Cheung S, Keating D, Xie P, Rosenwaks Z, Rienzi L, Innocenti F, Cimadomo D, Ubaldi FM, Sakkas D, Tucker MJ, and Nel-Themaat L
- Subjects
- Diffusion of Innovation, Female, Forecasting, History, 21st Century, Humans, Infertility diagnosis, Infertility physiopathology, Male, Pregnancy, Andrology trends, Clinical Laboratory Services trends, Fertilization in Vitro trends, Infertility therapy, Reproductive Medicine trends
- Abstract
The in vitro fertilization and andrology laboratories are at the center of assisted reproductive technologies and the place where technicians and embryologists manipulate gametes and preimplantation-stage embryos with the goal of achieving the best embryo for transfer. Through the years, these laboratories have seen developments in technique, technology, and testing. The goal of this Views and Interviews series is to bring together the thought leaders in the field and envision what the laboratories will look like in the next 10 years., (Copyright © 2021 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
22. 3D genomics across the tree of life reveals condensin II as a determinant of architecture type.
- Author
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Hoencamp C, Dudchenko O, Elbatsh AMO, Brahmachari S, Raaijmakers JA, van Schaik T, Sedeño Cacciatore Á, Contessoto VG, van Heesbeen RGHP, van den Broek B, Mhaskar AN, Teunissen H, St Hilaire BG, Weisz D, Omer AD, Pham M, Colaric Z, Yang Z, Rao SSP, Mitra N, Lui C, Yao W, Khan R, Moroz LL, Kohn A, St Leger J, Mena A, Holcroft K, Gambetta MC, Lim F, Farley E, Stein N, Haddad A, Chauss D, Mutlu AS, Wang MC, Young ND, Hildebrandt E, Cheng HH, Knight CJ, Burnham TLU, Hovel KA, Beel AJ, Mattei PJ, Kornberg RD, Warren WC, Cary G, Gómez-Skarmeta JL, Hinman V, Lindblad-Toh K, Di Palma F, Maeshima K, Multani AS, Pathak S, Nel-Themaat L, Behringer RR, Kaur P, Medema RH, van Steensel B, de Wit E, Onuchic JN, Di Pierro M, Lieberman Aiden E, and Rowland BD
- Subjects
- Adenosine Triphosphatases chemistry, Algorithms, Animals, Cell Nucleolus ultrastructure, Cell Nucleus ultrastructure, Centromere ultrastructure, Chromosomes chemistry, Chromosomes, Human chemistry, Chromosomes, Human ultrastructure, DNA-Binding Proteins chemistry, Genome, Human, Genomics, Heterochromatin ultrastructure, Humans, Interphase, Mitosis, Models, Biological, Multiprotein Complexes chemistry, Telomere ultrastructure, Adenosine Triphosphatases genetics, Adenosine Triphosphatases physiology, Biological Evolution, Chromosomes ultrastructure, DNA-Binding Proteins genetics, DNA-Binding Proteins physiology, Eukaryota genetics, Genome, Multiprotein Complexes genetics, Multiprotein Complexes physiology
- Abstract
We investigated genome folding across the eukaryotic tree of life. We find two types of three-dimensional (3D) genome architectures at the chromosome scale. Each type appears and disappears repeatedly during eukaryotic evolution. The type of genome architecture that an organism exhibits correlates with the absence of condensin II subunits. Moreover, condensin II depletion converts the architecture of the human genome to a state resembling that seen in organisms such as fungi or mosquitoes. In this state, centromeres cluster together at nucleoli, and heterochromatin domains merge. We propose a physical model in which lengthwise compaction of chromosomes by condensin II during mitosis determines chromosome-scale genome architecture, with effects that are retained during the subsequent interphase. This mechanism likely has been conserved since the last common ancestor of all eukaryotes., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2021
- Full Text
- View/download PDF
23. Cryopreservation of eggs.
- Author
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Nagy ZP, Nel-Themaat L, Chang CC, Shapiro DB, and Berna DP
- Subjects
- Female, Freezing, Humans, Molecular Biology methods, Vitrification, Cryopreservation methods, Fertilization in Vitro methods, Oocytes growth & development
- Abstract
Oocyte cryopreservation is playing an increasingly important role in the field of human infertility treatment. The ability to store viable oocytes for later use has given many women the option to delay childbearing in order to pursue other ventures in life, without the concern of losing the opportunity to have a family. Furthermore, oocyte cryopreservation is very valuable for diseased patients who have to undergo treatments that may compromise fertility. Also, infertility patients who produce large numbers of oocytes during a retrieval cycle now have the option of storing some eggs prior to fertilization, thereby reducing the number of embryos that have to be managed. Lastly, oocyte cryopreservation enables egg donation programs that are independent of fresh donations, which makes it possible for numerous recipients to benefit from a single donor.Traditionally, slow freezing was the only method available for oocyte cryopreservation. However, recent years have shown that ultrarapid cooling of oocytes results in higher survival and developmental rates. Thus, vitrification is today's preferred method of oocyte cryopreservation and therefore the only technique described.In this chapter, we present two reliable methods of oocyte vitrification that have been in use for several years and that have been experimentally validated. Since no single vitrification method is clearly superior to the rest, other systems are also briefly described to give the reader options when deciding which methods to utilize in their practice.
- Published
- 2014
- Full Text
- View/download PDF
24. Cryopreservation of oocytes in experimental models.
- Author
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Chang CC, Nel-Themaat L, and Nagy ZP
- Subjects
- Animals, Calcium Signaling, Cryoprotective Agents pharmacology, Cytoskeleton ultrastructure, Mice, Oocytes drug effects, Oocytes ultrastructure, Cryopreservation, Models, Animal, Oocytes physiology
- Abstract
Until recently, success in oocyte cryopreservation has been very limited mainly due to poor understanding of the complex physiological processes that lead to cell damage during cryopreservation. In the past three decades, however, a wealth of information has been collected using various different animal models, which has led to development of new technologies and optimization of existing ones. The use of these models has provided the opportunity for research that may not have been possible with human material. Today, results of these studies still continue to form the basis of oocyte cryobiology. This review discusses these studies, especially the physiological impacts of cryopreservation on oocyte biology. It will also focus on the role that animal models have played in improvement strategies, validation before translating new techniques into the human model and the advances made in the human in IVF because of these animal models. Finally, existing investigations and their potential impact in other areas of research will be discussed. Until recently, success in oocyte cryopreservation has been very limited mainly due to poor understanding of the complex physiological processes that lead to cell damage during cryopreservation. In the past three decades, however, a wealth of information has been collected using various different animal models, which has led to development of new technologies and optimization of existing ones. The use of these models provided the opportunity for research that may not have been possible with human material. Today, animal models still continuously provide imperative data that facilitate further advancements in oocyte cryobiology. This review will focus on the physiological impacts, current improvement strategies and future applications of oocyte cryopreservation using animal models as they benefit not only human oocyte cryopreservation procedures, but also the human species through their usefulness in agriculture, medicine and conservation., (Copyright © 2011 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
25. Sertoli cell behaviors in developing testis cords and postnatal seminiferous tubules of the mouse.
- Author
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Nel-Themaat L, Jang CW, Stewart MD, Akiyama H, Viger RS, and Behringer RR
- Subjects
- Animals, Cell Membrane physiology, Cell Membrane ultrastructure, Cytoplasm ultrastructure, Embryo, Mammalian metabolism, Fluorescent Antibody Technique, Fluorescent Dyes, GATA4 Transcription Factor genetics, Gene Expression, Genes, Reporter, Gestational Age, Green Fluorescent Proteins genetics, Luminescent Proteins genetics, Male, Mice, Mice, Transgenic, Microscopy, Fluorescence, Organ Culture Techniques, Rats, SOX9 Transcription Factor metabolism, Spermatozoa cytology, Testis metabolism, Animals, Newborn physiology, Fetal Development, Fetus cytology, Seminiferous Tubules cytology, Sertoli Cells physiology, Testis embryology
- Abstract
Sertoli cells are the primary structural component of the fetal testis cords and postnatal seminiferous tubules. Live imaging technologies facilitate the visualization of cell morphologies and behaviors through developmental processes. A transgenic mouse line was generated using a fragment of the rat Gata4 gene to direct the expression of a dual-color fluorescent protein reporter in fetal and adult Sertoli cells. The reporter encoded a red fluorescent protein, monomeric Cherry (mCherry), fused to histone 2B and enhanced green fluorescent protein (EGFP) fused to a glycosylphosphatidylinositol sequence, with a self-cleaving 2A polypeptide separating the two fusion proteins. After translation, the red and green fluorescent proteins translocated to the nucleus and plasma membrane, respectively, of Sertoli cells. Transgene expression in testes was first detected by fluorescent microscopy around Embryonic Day 12.0. Sertoli cell division and migration were visualized during testis cord formation in organ culture. Initially, the Sertoli cells had mesenchyme-like morphologies and behaviors, but later, the cells migrated to the periphery of the testis cords to become epithelialized. In postnatal seminiferous tubules, Sertoli nuclei were evenly spaced when viewed from the external surface of tubules, and Sertoli cytoplasm and membranes were associated with germ cells basally in a rosette pattern. This mouse line was bred to previously described transgenic mouse lines expressing EGFP in Sertoli cytoplasm or a nuclear cyan fluorescent protein (Cerulean) and mCherry in plasma membranes of germ cells. This revealed the physical relationship between Sertoli and germ cells in developing testis cords and provided a novel perspective on Sertoli cell development.
- Published
- 2011
- Full Text
- View/download PDF
26. Illuminating testis morphogenesis in the mouse.
- Author
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Nel-Themaat L, Gonzalez G, Akiyama H, and Behringer RR
- Subjects
- Animals, Male, Mice, Mice, Transgenic, Organogenesis, Testis embryology
- Abstract
The mammalian testis is a complex organ composed of multiple cell types that are organized into seminiferous tubules and an interstitium, producing spermatozoa and hormones, respectively. During embryogenesis, the testis forms from the genital ridge associated with the embryonic kidney called the mesonephros. After germ cells migrate into the genital ridge, the Sertoli cell-germ cell mass forms and undergoes morphogenetic changes to generate testis cords, the precursors of the seminiferous tubules. Static images of the fetal testis at sequential stages of development provide structural information about cord formation. Transgenic mice that express fluorescent protein reporters offer new opportunities for time-lapse imaging to visualize live cells and their behaviors during testis differentiation and morphogenesis.
- Published
- 2010
- Full Text
- View/download PDF
27. Morphometric analysis of testis cord formation in Sox9-EGFP mice.
- Author
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Nel-Themaat L, Vadakkan TJ, Wang Y, Dickinson ME, Akiyama H, and Behringer RR
- Subjects
- Animals, Gene Knock-In Techniques, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, Male, Mice, Mice, Mutant Strains, SOX9 Transcription Factor genetics, Sertoli Cells cytology, Sertoli Cells physiology, Testis metabolism, SOX9 Transcription Factor metabolism, Testis anatomy & histology, Testis embryology
- Abstract
Sox9-EGFP knockin mice were generated to label Sertoli cells and visualize testis cord formation during development. Confocal microscopy and morphometric analysis of developing cords were performed. Serial histological sections were used for three-dimensional cord reconstruction. Initially, gonad length decreased from embryonic day (E) 11.5 to E13.5, but increased thereafter, while gonad width doubled every 12 hours from E11.5 through E14.5. At E12.5, the average number of cords was 12.5, whereas this decreased to 10.4 at E13.5 and E14.5. Cord number at a given time point varied between gonads and influenced dimensions. The initial cords that formed were complex and branches were common. Time-lapse imaging revealed an intricate behavior of the Sertoli-germ cell mass and cellular exchange between connected neighboring cords. These results suggest that cord formation is a highly dynamic process that subsequently becomes refined to establish the final number of seminiferous tubule precursors.
- Published
- 2009
- Full Text
- View/download PDF
28. Mouse early oocytes are transiently polar: three-dimensional and ultrastructural analysis.
- Author
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Kloc M, Jaglarz M, Dougherty M, Stewart MD, Nel-Themaat L, and Bilinski S
- Subjects
- Animals, Centrioles ultrastructure, Female, Humans, Immunohistochemistry, Mice, Models, Anatomic, Ovary cytology, Cell Polarity, Oocytes ultrastructure, Organelles ultrastructure
- Abstract
The oocytes of many invertebrate and non-mammalian vertebrate species are not only asymmetrical but also polar in the distribution of organelles, localized RNAs and proteins, and the oocyte polarity dictates the patterning of the future embryo. Polarily located within the oocytes of many species is the Balbiani body (Bb), which in Xenopus is known to be associated with the germinal granules responsible for the determination of germ cell fate. In contrast, in mammals, it is widely believed that the patterning of the embryo does not occur before implantation, and that oocytes are non-polar and symmetrical. Although the oocytes of many mammals, including mice and humans, contain Bbs, it remains unknown how and if the presence of Bbs relates to mouse oocyte and egg polarity. Using three-dimensional reconstruction of mouse neonatal oocytes, we showed that mouse early oocytes are both asymmetrical and transiently polar. In addition, the specifics of polarity in mouse oocytes are highly reminiscent of those in Xenopus early oocytes. Based on these findings, we conclude that the polarity of early oocytes imposed by the position of the centrioles at the cytoplasmic bridges is a fundamental and ancestral feature across the animal kingdom.
- Published
- 2008
- Full Text
- View/download PDF
29. Cloned embryos from semen. Part 2: intergeneric nuclear transfer of semen-derived eland (Taurotragus oryx) epithelial cells into bovine oocytes.
- Author
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Nel-Themaat L, Gómez MC, Pope CE, Lopez M, Wirtu G, Jenkins JA, Cole A, Dresser BL, Bondioli KR, and Godke RA
- Subjects
- Animals, Bromodeoxyuridine pharmacology, Cell Cycle physiology, Cells, Cultured, DNA biosynthesis, Epithelial Cells cytology, Female, Flow Cytometry, Male, Oocytes cytology, Antelopes physiology, Cattle, Cloning, Organism methods, Epithelial Cells physiology, Nuclear Transfer Techniques, Oocytes physiology, Semen physiology
- Abstract
The production of cloned offspring by nuclear transfer (NT) of semen-derived somatic cells holds considerable potential for the incorporation of novel genes into endangered species populations. Because oocytes from endangered species are scarce, domestic species oocytes are often used as cytoplasts for interspecies NT. In the present study, epithelial cells isolated from eland semen were used for intergeneric transfer (IgNT) into enucleated bovine oocytes and compared with bovine NT embryos. Cleavage rates of bovine NT and eland IgNT embryos were similar (80 vs. 83%, respectively; p > 0.05); however, development to the morula and blastocyst stage was higher for bovine NT embryos (38 and 21%, respectively; p < 0.0001), than for eland IgNT embryos (0.5 and 0%, respectively). DNA synthesis was not observed in either bovine NT or eland IgNT cybrids before activation, but in 75 and 70% of bovine NT and eland igNT embryos, respectively, cell-cycle resumption was observed at 16 h postactivation (hpa). For eland IgNT embryos, 13% had > or = 8 cells at 84 hpa, while 32% of the bovine NT embryos had > or = 8 cells at the same interval. However, 100 and 66% of bovine NT and eland IgNT embryos, respectively, that had > or = 8 cells synthesized DNA. From these results we concluded that (1) semen-derived epithelial cell nuclei can interact and be transcriptionally controlled by bovine cytoplast, (2) the first cell-cycle occurred in IgNT embryos, (3) a high frequency of developmental arrest occurs before the eight-cell stage in IgNT embryos, and (4) IgNT embryos that progress through the early cleavage stage arrest can (a) synthesize DNA, (b) progress through subsequent cell cycles, and (c) may have the potential to develop further.
- Published
- 2008
- Full Text
- View/download PDF
30. Cloned embryos from semen. Part 1: in vitro proliferation of epithelial cells on embryonic fibroblasts after isolation from semen by gradient centrifugation.
- Author
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Nel-Themaat L, Gómez MC, Pope CE, Lopez M, Wirtu G, Cole A, Dresser BL, Lyons LA, Bondioli KR, and Godke RA
- Subjects
- 3T3 Cells, Animals, Cell Culture Techniques, Cell Separation methods, Centrifugation, Density Gradient, Cryopreservation, Fibroblasts physiology, Male, Mice, Microsatellite Repeats, Models, Biological, Povidone pharmacology, Semen cytology, Sheep physiology, Silicon Dioxide pharmacology, Cell Proliferation, Cloning, Organism methods, Embryonic Stem Cells physiology, Epithelial Cells physiology, Semen physiology
- Abstract
Although epithelial-like somatic cells have been previously isolated from semen, cell proliferation rates were low. Culture of whole semen samples resulted in loss of potentially valuable spermatozoa. The aims of the present study were to: (1) isolate somatic cells from semen, while preserving sperm viability, and (2) optimize in vitro culture conditions for semen-derived epithelial cells. Density gradient centrifugation of washed ejaculates of two rams (Ovis aries) (n = 24) and one eland bull (Taurotragus oryx) (n = 4) was performed using a three-layer discontinuous Percoll column consisting of 90% (P-90), 50% (P-50), and 20% (P-20) Percoll. In vitro culture and Trypan Blue staining indicated that live somatic cells settled in the P-20 layer. Nonmotile spermatozoa were recovered at the P-50 and P-90 interfaces, whereas motile spermatozoa were collected in the pellet from the P-90 layer. Subsequently, somatic cells isolated from the P-20 layer were plated either on inactivated 3T3 mouse embryonic fibroblast feeder layers, collagen-coated plates with 3T3 feeder cell inserts, or on collagen-coated plates. Initial somatic cell plating was similar among treatments, but proliferation significantly increased when cocultured with 3T3 cells (feeder or insert). Furthermore, two different types of epithelial cells were obtained. The exact origin of the cells in the male reproduction system is uncertain and probably variable. The present method of cell isolation and in vitro culture may be of value for preserving endangered species. Specifically, cells isolated and cultured from cryopreserved semen of nonliving males could be used for producing embryos by somatic cell nuclear transfer.
- Published
- 2008
- Full Text
- View/download PDF
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