In vitro fertilisation in domestic mammals—a brief overview

Many factors influence the final oocyte maturation, fertilisation, and early embryo development, and there are both similarities and differences between species. When comparing the advancement of assisted reproductive technologies (ARTs), the development in the bovine species is not far behind the medical front, with around one million in vitro-produced bovine embryos each year. This rate of progress is not seen in the other domestic species. This review aims to give an overview of the development and specific difficulties of in vitro embryo production in various domestic animal species, with the main focus on cows, pigs, and cats. In production animals, the aim of ARTs is commonly to increase the genetic progress, not to treat reproductive failure. The ARTs are also used for preservation of genetic diversity for the future. However, specifically for oocyte maturation, fertilisation, and early embryonic development, domestic mammals such as the cow and pig can be used as models for humans. This is particularly attractive from an animal welfare point of view since bovine and porcine oocytes are available in large numbers from discarded slaughterhouse material, thereby decreasing the need for research animals. Both for researchers on the animal and human medical fronts, we aim for the development of in vitro production systems that will produce embryos and offspring that are no different from those conceived and developed in vivo. Species-comparative research and development can provide us with crucial knowledge to achieve this aim and hopefully help us avoid unnecessary problems in the future.     

The Influence of Growth Factors on the Development of Preimplantation Mammalian Embryos

The development of the preimplantation mammalian embryo from a fertilized egg to a blastocyst capable of implanting in the uterus is a complex process. Cell division must be carefully programmed. The embryonic genome must be activated at the appropriate stage of development, and the pattern of gene expression must be carefully coordinated for the initiation of the correct program of differentiation. Cell fates must be chosen to establish specific cell types such as the inner cell mass and the trophectoderm, which give rise to the embryo proper and the placenta, respectively. This review summarizes recent findings concerning the influence of growth factors on the development of preimplantation mammalian embryos. Maternal factors secreted into the lumen of the female reproductive tract as well as substances synthesized by the developing embryo itself help to regulate this process. Studies of embryos in culture and investigations using homologous recombination to create embryos and animals null for specific genes have enabled the identification of several growth factors that appear essential for preimplantation mammalian embryo development. Some of the factors are required maternal factors; others are embryo-derived autocrine and paracrine factors. Studies using molecular biology are beginning to identify differences in the patterns of genes expressed by naturally derived embryos and those developing in culture. The knowledge gained from studies on growth factors, media, embryonic development, and gene expression should help improve culture conditions for embryos and will provide for safer outcomes from assisted reproductive procedures in human and animal clinics.     

新建IVF实验室使用前的生物学检测

目的检测新建IVF实验室培养体系的可靠与否。方法采用鼠胚生物学实验(小鼠体外受精和小鼠体内胚的体外培养)和人精子体外存活实验检测IVF实验室的培养体系,并观察鼠胚的体外发育情况和人精子体外存活情况。结果小鼠体外受精实验的平均囊胚形成率低于小鼠体内胚实验组(85.50%vs 90.51%),人精子体外存活实验结果稳定(SMI0.85),受测样品合格。结论上述方法很好地检测了IVF实验室的稳定情况,而小鼠体内胚的体外培养更能准确地检测新的IVF实验室。     

Social policy considerations in noncoital reproduction

A review is provided of social issues posed by the reproductive technologies of artificial insemination by donor, in vitro fertilization and embryo transfer, surrogate motherhood, surrogate embryo transfer, and the implantation of previously frozen embryos. These issues include possible use unrelated to infertility, status of the embryo, identification of parents, donor screening and anonymity, and commercialization. The policy recommendations of Great Britain's Warnock Committee and Australia's Waller Committee are briefly discussed, as is the current absence of a comparable commission in the United States. Prompt state legislative action is proposed to establish the gestational mother as legal mother and to forbid the sale of human embryos. Action by professional organizations and a national advisory commission are recommended to formulate social policy protecting the interests of children resulting from reproductive technologies.     

Ethical and legal issues in therapeutic cloning and the study of stem cells

Therapeutic cloning is a new technology with great medical potential, particularly in the area of transplantation medicine. It involves the transfer of the nucleus of a patient's cell into an enucleated donor oocyte for the purpose of generating an embryo. This embryo is allowed to grow until the blastocyst stage, at which time stem cells can be obtained and differentiated into the tissue needed. Stem cells can also be obtained from adult tissues, as they seem to have sufficient plasticity to use for the stated purpose. A literature review was performed, and it is clear that the main controversy regarding the use of stem cells is the origin. Few people would object to their use if obtained from adult tissues; however, many oppose harvesting them from embryos in the blastocyst stage regardless of whether 1) they are obtained from surplus embryos donated by couples after assisted reproductive techniques, or 2) they are specially manufactured for research purposes. The central reason is the consideration that embryos should be treated as full humans from the moment of fertilization. This argument is also at the bottom of an older discussion regarding the validity of abortion. There is no consensus at the present time in this regard, and it is unlikely one will be forthcoming in the future. Arguments on both sides of the issue are presented, but emphasis is made on the need for using this technology for research purposes because of its potential value as a therapeutic tool.     

单细胞RNA测序在干细胞生物学中的应用研究进展

细胞间的变异或异质性是干细胞群的基本和内在特征。传统的组学分析是在混合细胞群体上进行,导致这些差异被掩盖。近年来,单细胞基因组、表观基因组、转录组测序等技术发展迅速,为全面解析细胞异质性和识别不同表型细胞类型提供了强有利工具。这些方法应用于不同类型的干细胞,包括多能干细胞和组织特异性干细胞,在干细胞领域取得了令人兴奋的新发现。本文综述了单细胞组学测序技术的最新进展,并对单细胞组学测序的方法和应用进行了展望。     

胚胎冷冻保存技术及进展

随着冷冻保存技术的发展,胚胎的冷冻保存在生殖医学中的地位越来越重要,已成为辅助生殖的核心步骤及生育力保存的重要方法。过去几年中,全球范围内胚胎冷冻周期数呈指数级增长。胚胎冷冻的优点不断凸显,冻胚移植越来越受人们的关注。如何完善胚胎冷冻技术及如何改善临床结局是目前关注的重点及努力的方向。因此,本文从胚胎冷冻技术的发展历程、应用、分类及目前研究进展几个方面进行全面述评。     

Reconfiguring a hospital towards general practice: the case of Peamount

Background  The decline in incidence of tuberculosis in Ireland has led Peamount Hospital to reconfigure its services towards the needs of general practice. Aims  To ascertain views of local GPs on their current use of Peamount, and how the hospital might best serve their future needs. Methods  Self-administered postal questionnaires sent to 151 GPs practicing in Peamount’s catchment area, to determine their current use of services, and likely future use of proposed services. Total valid response rate 64% (n = 84). Results  Responses indicated a lack of awareness of many services currently available, with a concomitant under-use of these services. The majority of GPs would use planned future services, particularly expanded radiology services. Conclusions  This survey promoted awareness among GPs of services available at Peamount. It informed the planning of future services and promoted a culture of involving local GPs in the planning of services of which they will be the users.     

快冻和慢冻法对胚胎复苏结局的比较

目的:比较辅助生殖技术中快冻(玻璃化法)和慢冻(程序化法)两种冷冻方法对卵裂期胚胎的冻融效果.方法:将复苏后全部卵裂球存活的胚胎定义完整存活胚胎,同一病人由于有多余冻融胚胎而行2次及以上移植周期的称为重复周期.对577个快冻周期和276个慢冻周期的相关资料进行回顾性统计学分析,比较两组冻融胚胎的存活率、完整存活率、重复...     

Preimplantation genetic diagnosis of chromosomal abnormalities by multicolour fluorescence in situ hybridisation

Preimplantation genetic diagnosis (PGD) is an early diagnosis of genetic disorders, prior to the onset of pregnancy. PGD incorporates the latest techniques in assisted reproduction and molecular genetics. Embryos or oocytes are biopsied during culture in vitro and genetic analysis is carried out on the blastomeres or polar bodies. Embryos shown to be free of the genetic disease under investigation are transferred to the uterus. Multicolour fluorescence in situ hybridisation (FISH) is used to diagnose numerical and certain structural abnormalities of chromosomes in the embryo. The common probes used are for chromosomes 13, 18, 21, X and Y. FISH can also be used for PGD of translocations, when one of the parents is a carrier. PGD was carried out recently in 4 cases using multicolour FISH. In one of the embryos, trisomy 18 was detected. Tetraploidy was seen in another embryo. Only chromosomally normal embryos were transferred back to the uterus. Care has to be taken while interpreting FISH signals as the signal may be split, diffused, superimposed or in a different focus.     

激光薄化部分透明带辅助孵化的临床应用

目的:探讨激光薄化部分透明带辅助孵化在体外受精-胚胎移植(IVF-ET)周期中的临床应用。方法:选择前次IVF失败、透明带增厚或异常、女方年龄≥37岁、胚胎质量差者共168个新鲜取卵周期的移植胚胎,采用激光薄化部分透明带后进行移植。结果:前次IVF失败者的临床妊娠率为48.8%(20/41)、胚胎种植率为25.8%(30/116);透明带增厚(>16μm)或形态不规则者的临床妊娠率为40.3%(25/62)、胚胎种植率为26.5%(36/136);女方年龄≥37岁的临床妊娠率为23.9%(11/46)、胚胎种植率为11.0%(14/127);胚胎质量差者的临床妊娠率为26.3%(5/19)、胚胎种植率为10.8%(5/46)。结论:对前次IVF失败者和透明带较厚患者的透明带进行局部激光薄化,可取得很好的助孕结果。     

磁共振血管成像（MRA）的应用进展

磁共振血管成像（MRA）是一种较新的血管成像技术,由于它具有无创伤、无辐射、快捷、价格便宜的优点以及技术的不断革新,近几年被广泛用于临床。本文对磁共振血管成像的原理、优缺点以及临床应用的新进展进行综述。     

Gonadotropin-releasing hormone agonist ovulation trigger—beyond OHSS prevention

In this review the advantages of the gonadotropin-releasing hormone agonist (GnRHa) trigger are discussed beyond those immediately associated with ovarian hyperstimulation syndrome (OHSS) prevention. The GnRHa trigger concept has sparked the development of novel protocols, enriching the assisted reproductive technology (ART) armamentarium for the benefit of present and future patients. Thus, GnRHa trigger already has a pivotal role, not only for the standard in vitro fertilisation (IVF) patient, but also for patient groups like oocyte donors, cancer patients, patients with poor ovarian reserve, and patients with immature oocyte syndrome and empty follicle syndrome. Herein, we discuss the importance of the GnRHa-elicited midcycle FSH surge and the potential improvement in oocyte yield and embryo competence.     

辅助生殖技术中选择性单胚胎移植的研究进展

辅助生殖技术（assisted reproductive technology, ART）已成为不孕症患者最有效的治疗方法,但多胎妊娠为其最突出的并发症之一。多胎妊娠常引起羊水过多、先兆子痫、低体质量儿、贫血等多项严重的母婴并发症。避免多胎妊娠的方法是单胚胎移植,选择性单胚胎移植已经成为生殖医学未来的发展方向,单胚胎的选择为临床难题。如何保证临床妊娠率又显著降低各类并发症？对于35岁以下的卵巢储备功能正常患者或有优质囊胚的高龄患者,可通过检测其胚胎发育过程中的代谢产物、胚胎持续监测或植入前遗传学诊断,筛选最具发育潜能的胚胎进行移植,改善临床结局。本文通过文献回顾,探讨选择性单胚胎移植的临床应用前景。     

B超下子宫内膜形态分型对冷冻胚胎移植结局的影响

目的辅助生殖技术已成为治疗不孕疾病的常规手段,B超是辅助生殖技术的必要手段,文中探讨B超下子宫内膜形态分型对于冷冻胚胎移植结局的影响。方法在冷冻胚胎移植周期中,分别按照内膜厚度、移植胚胎类型、内膜准备方案分组,各组内分别比较B超下A型和B型子宫内膜与冷冻胚胎移植临床种植率的关系。结果按照不同内膜厚度分组,内膜厚度≤8mm组及9-11 mm组内,A型和B型子宫内膜对于冷冻胚胎移植的种植率差异均无统计学意义(P>0.05);≥12mm组内,A型内膜冷冻胚胎移植的种植率显著高于B型内膜(P<0.05)。按照不同胚胎类型分组,卵裂胚组和囊胚组内,A型和B型子宫内膜对于冷冻胚胎移植的妊娠率差异均无统计学意义(P>0.05)。按照不同内膜准备方案分组,替代周期组、自然周期组和促排周期组内,A型和B型子宫内膜对于冷冻胚胎移植的妊娠率差异均无统计学意义(P>0.05)。结论在内膜较厚的情况下,临床更适于选择A型内膜移植冷冻胚胎。     

不同时期胚胎线粒体拷贝数与胚胎自身形态学分型的关系研究

目的:探讨人类不同形态学分型的卵裂期胚胎和囊胚与自身线粒体拷贝数的关系。方法:选择在生殖中心因女性双侧输卵管梗阻行体外受精-胚胎移植（IVF-ET）助孕顺利娩出健康胎儿后,自愿丢弃冷冻的卵裂期胚胎和囊胚用于科学研究。将冷冻的胚胎解冻复苏后,依据胚胎发育的时期,将所有胚胎分为卵裂期胚胎冷冻组（D3冷冻胚胎组,n=63）和囊胚冷冻组（D5冷冻胚胎,n=82）,再根据冷冻胚胎的形态学评分标准,将冷冻卵裂期胚胎分为优质胚胎组（n=38）和较差胚胎组（n=25）,将冷冻囊胚分为优质囊胚组（n=52）和较差囊胚组（n=30）。采用实时PCR检测胚胎线粒体拷贝数,比较不同阶段胚胎和相同阶段不同质量的胚胎与自身线粒体拷贝数的差异。结果:D3冷冻胚胎组线粒体拷贝数明显低于D5冷冻胚胎组（t=9.34,P<0.02）,D3冷冻胚组中优质胚胎mtDNA拷贝数高于质量较差胚胎组（t=6.62,P<0.01）,D5冷冻胚组中优质胚胎mt DNA拷贝数明显高于质量较差胚胎组（t=8.03,P<0.04）。结论:不同时期胚胎mt DNA拷贝数对胚胎的发育潜能有重要影响,mtDNA拷贝数越高,胚胎质量越好。     

Non-invasive investigation of chronic stable angina--a practical overview for medical practitioners

How does one decide on the best non-invasive test to investigate stable coronary ischaemia? This is a very common question faced by many medical practitioners. Chronic stable angina is a common presentation encountered in general practitice. Upon clinical assessment and risk stratification the patient needs to be investigated further to confirm the diagnosis. The first investigational modality involves a non-invasive test. It is important that practitioners possess a practical knowledge of the array of different tests that are available so that the best suited one for each patient can be chosen. This article aims to compare the efficacy and accuracy and the practical utility of the different non-invasive tests for coronary ischaemia and aid the practitioner in making sound decisions in this regard.     

不同来源小鼠胚胎培养在辅助生殖实验室质量控制中的应用

目的:利用小鼠胚胎体外培养技术对新建人类辅助生殖实验室进行质量控制,以保证培养体系的可靠性,并比较两种小鼠胚胎培养方法在实验室质量控制中的作用。方法:采用小鼠配子体外授精法和2-细胞胚胎收集法对胚胎进行培养,观察胚胎发育情况。结果:小鼠配子体外授精法的受精率为80.98%,受精卵的卵裂率、优质胚胎率及囊胚形成率分别为90.60%、68.15%、85.93%与收集的体内2-细胞卵胚胎的88.98%、70.33%、83.89%比较无显著性差异,P>0.05。结论:两种不同来源鼠胚培养方法均可作为实验室培养体系检测的评价指标。对于新建的胚胎培养实验室,小鼠配子体外授精法可对IVF的全过程进行检测,更能反映培养体系对胚胎的影响,同时还可熟练IVF的操作技能。     

辅助生殖技术后流产胚胎核型与超声结果分析

目的 探讨辅助生殖技术(ART)治疗后妊娠早期影响胚胎发育的因素.方法 以85例不孕症患者早孕期流产胚胎为研究对象,分析绒毛染色体以及异常核型、不同受孕方式和年龄对超声结果的影响.结果 85例流产胚胎中异常核型占50.6％,全部为染色体数目异常;有胚芽的流产胚胎异常核型率(63.3％)显著高于无胚芽组(33.3％),差异有统计学意义(P=0.006);有胚芽的胚胎由体外受精联合胚胎移植技术(IVF)受精的比例(44.9％)较无胚芽组低(80.6％),差异有统计学意义(P=0.001);流产患者的平均年龄在有胚芽和无胚芽组间分别为(33.4 ± 5.2)岁和(33.0 ± 4.4)岁,但差异无统计学意义(P=0.713).结论 经ART妊娠后胚胎自然流产的异常核型主要是染色体数目异常,出现胚芽的胚胎中染色体异常率较高,IVF受精的胚胎空孕囊的比例较高,年龄对胚胎组织结构的发育无显著影响.     

体外受精治疗周期中剩余胚胎囊胚培养的临床价值

目的探讨体外受精治疗周期中d3移植和冷冻后剩余胚胎的体外发育潜能。方法对剩余胚胎继续培养至囊胚期,观察其囊胚发育率和质量,并分析治疗周期中剩余胚胎囊胚形成情况和妊娠结局的关系。结果收集115个IVF／ICSI-ET周期中的603枚剩余胚胎,囊胚培养后获得了222枚囊胚（36．82％）,其中优质囊胚49枚（8．13％）;36个周期（31．30％）共获得53枚冷冻囊胚（8．79％）;12例含有剩余胚胎来源囊胚的解冻移植周期,临床妊娠4例;≥6细胞、2PN来源胚胎囊胚形成率显著高于其他组（P〈0．05）;剩余胚胎有囊胚形成的周期临床妊娠率显著高于无囊胚形成组（P〈0．05）。结论根据d3胚胎形态学评分预测其发育潜能有一定局限性;通过囊胚培养筛选出剩余胚胎中具有发育潜能的并冷冻保存,是提高病人每个治疗周期可用胚胎数的可行方法;剩余胚胎囊胚形成情况可有效预测妊娠结局。