Dr Jorge Ten

What are an embryo’s nutritional requirements prior to transfer to the mother?

During in vitro fertilisation processes, for the first few days of their lives, human embryos have to develop outside the mother’s body in special incubators.  Temperature and pH conditions need to be optimum and embryos also need to have access to all the necessary ingredients in order to feed and, in doing so, meet their energy requirements. Culture media are used for this. […]

2017-07-05T09:23:38+02:007 de July de 2017|0 Comments

Safety in the in vitro fertilisation (IVF) laboratory so that errors are avoided

A recent news item generated alarm regarding safety procedures in in vitro fertilisation (IVF) laboratories. On this occasion, a hospital in Utrecht is currently investigating 26 potential cases of confusion as a result of insemination with semen samples from different patients. We say that making mistakes is only natural, but when we are working with gametes and embryos, the error rate must be zero.
This recent news instils fear in patients since they are not familiar with the safety measures present in IVF laboratories. This fear can generate a lack of confidence in the clinic and its staff.  If we take into account that assisted reproduction treatment generates stress, news of this kind increases fears even more and generates even greater stress. […]

2017-03-02T14:30:18+02:003 de March de 2017|0 Comments

What is a spermatid?

Spermatozoa production takes place in the testicular seminiferous tubules and the process is known as spermatogenesis.  At the end of this process, a germ cell generates 4 mature spermatozoa which will survive in the human body for between 62 and 75 days.  The final stage in spermatogenesis, known as spermiogenesis, is a cell differentiation and maturation process consisting of the change from spermatids to spermatozoa.  As can be seen in the picture, the spermatids develop from secondary spermatocites and have already undergone Meiosis I and II division. They have a normal set of chromosomes (haploid) which means that fertilisation of a mature egg can take place. Therefore, and despite the fact that they are immature cells, they can be used in assisted reproduction techniques using ICSI when there are no mature sperm in samples taken from the ejaculate or testicles. […]

2017-01-13T14:38:30+02:0013 de January de 2017|0 Comments

Why does embryonic arrest sometimes happen during in vitro development?

Many factors can intervene in arrest processes during embryo development which mean cell division is detained and, therefore, it is not possible to implant the embryo in the mother’s uterus and bring about a pregnancy.
In the first instance, the conditions for development are essential.  Embryos that develop in vitro are subjected to a number of artificial conditions that do not exist in vivo and which will always be less than optimum. Embryos which were apparently viable can suffer embryonic arrest. Huge efforts have been made over the last few years to try and mimic what happens inside the mother and replicate those conditions in laboratory processes.  Most of all, the concentration of oxygen in incubators has been reduced, going from 20% down to 5%. The composition of the culture means has also been improved. This, along with exhaustive monitoring of pH and osmotic concentration, means that we can routinely carry out prolonged embryo development up to blastocyst stage in order to achieve improved embryo selection and increase pregnancy rates. […]

2018-03-26T18:18:33+02:0019 de August de 2016|2 Comments

Cryopreserved embryos: Does biobank storage time affect their subsequent viability?

It has been almost 30 years since the first pregnancy from cryopreserved embryos was achieved (Trounson and Mohr, 1983). Ever since then, numbers have been steadily growing at biobanks in assisted reproduction centres, mainly due to the optimisation of reproductive treatments. Our goal is to retrieve a satisfactory amount of good quality embryos (one that is enough for a fresh transfer and also for cryopreservation) by means of an ovarian stimulation cycle. These embryos may be used for future pregnancy attempts, although couples can choose to donate them for reproductive purposes, assign them to specific research projects or dispose of them. Yet, general evidence shows that many couples, mainly those that achieve pregnancy in their first fresh attempt, choose to keep them frozen without a specific end or plan in mind for the future. […]

2016-08-04T13:23:29+02:0022 de January de 2016|0 Comments

The male factor in infertility

In contrast with the old-fashioned belief that reproduction issues are a female thing, current figures are clear: 47% of infertility cases in a couple are down to an issue with the man. Therefore, when a couple has infertility issues and they seek the help of a clinic specialising in assisted reproduction, the tests and analyses are carried out on both members of the couple. This practice of looking into both the female factor and the male factor is now common and carried out by all experts in the field, but there is still a lack of understanding of the fertility issues which men can have. What are they? What solutions do leading assisted reproduction clinics offer nowadays?
The most common issues amongst men are “changes in the sperm count with no apparent cause”, explains Instituto Bernabeu in Alicante. That is, a low number of sperm, poor sperm mobility or abnormal morphology. Additionally, there may be more concrete and identifiable reasons for changes in sperm such as obstruction issues, infection, diseases or genetic reasons which impede egg fertilisation or which affect embryo quality. […]

2016-08-04T13:30:33+02:003 de December de 2015|0 Comments

Vitrification: the cold revolution

Vitrification is generally associated with delaying maternity. It involves preserving eggs at low temperatures so that they may be used in the future. This is, in itself, astounding since it enables gametes to be preserved by means of advanced and ultra-rapid cell freezing so that they may be used sometime in the future. The uses to which this technique may be put are so varied and numerous and have changed the work environment in the most prestigious of fertility clinics to such an extent that experts have no doubts about referring to vitrification as a ‘revolutionary’ procedure.
“We could say that cryopreservation is currently the most important aspect of any assisted reproduction clinic” assures Dr Jorge Ten, head of the Reproductive Biology Operational Unit at Instituto Bernabeu in Alicante. In the words of this expert, this technique “has changed enormously over the last 6 to 8 years”. Vitrification was initially carried out using “slow freezing techniques which caused cell damage” in the oocyte. This cell, “in the case of women, is the largest in the human body and has the greatest content in water. Therefore, when frozen, it produced poorer results due to the formation of ice crystals which damaged its structure”. The ice crystals which formed as a result of the aforementioned slow freezing and the high water content in the cell meant that survival rates were “between 20 and 30%. Almost no oocytes survived”. […]

2016-08-04T13:54:31+02:0028 de October de 2015|0 Comments
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