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The Clinical Embryologist Volume 10, Issue 2 Summer, 2007

Oocyte and embryo respiration rate measurements in a clinical setting – Potential to improve embryo selection?

Lynette Scott1, Ph.D., Niels B. Ramsing2, Ph.D., 1Fertility Centers of New England, Reading, MA, USA, 2Unisense FertiliTech, Science Center Skejby, Aarhus, Denmark scottl@fertilitycenter.com

The most common form of embryo selection in human Assisted Reproductive Technologies is morphology. Embryos are assessed at specific time points and judgments made regarding their ability to implant based on these very limited snapshot assessments. These can be performed on day 1, 2, 3 and 5 of development. There are data showing that combinations of scoring times lead to increased implantation, which is logical as it increases the points of assessment (Scott et al., 2007). Although selection criteria have improved and become more efficient with this gated or sequential scoring, it is still not sufficient to effectively select one embryo that has high implantation potential all the time, and with implantation rates still no greater than about 50% in ideal cases. New technologies are being developed to look at a more dynamic and continual assessment of oocytes and embryos in order to find other factors that can indicate the health and ability of the embryo to implant. (Read More )

 

The Clinical Embryologist Volume 7, Issue 4 Winter, 2004

Microanalysis of Rapid Temperature Fluctuations in IVF Culture Systems.

Lynette Scott, Ph.D., HCLD, The Fertility Center of New England, Reading, MA Scottl@FertilityCenter.com

Temperature control in IVF laboratories is an ongoing controversial issue. There is a whole, lucrative industry around helping us keep oocytes and embryos warm. There are papers showing negative affects of cooling on outcome but many of these are not well controlled. There are also some major laboratories in the country that do not believe in keeping everything at 37°C all the time and it does not appear to affect their results. Another factor that is hardly ever taken into account is the ambient temperature. In the cold northern states, where we are seemingly forever at a strict set temperature; others do not. Does this play a role in the affects of cooling? Can a difference between an ambient temperature of 22 and 26°C be that important? In any paper where temperature is a critical issue, there is almost never a reference to the ambient temperature in the laboratory. It is well known that changes both within the oocyte and the embryo do occur with a decrease in the temperature. But are these really that detrimental — especially considering that we can cool and freeze both oocytes and embryos fairly effectively? If cooling does affect them, when and over what time period does this occur and is it due to a sudden single temperature dip — a “one off” — or is it due to continual abuse or to very rapid temperature perturbations? (Read More)

 

The Clinical Embryologist Volume 7, Issue 2 Summer, 2004

The Timing of ICSI: When Is the Oocyte Ready? Or does It Matter?

Lynette Scott, Ph.D., HCLD, The Fertility Centers of New England, Reading, MA Relevant Background: ICSI was first performed on a routine basis in Belgium by Andre Van Steirteghem’s lab initially for severe male factor (Palermo, Joris, Devroey, Van Steirteghem, 1992). ICSI is currently a standard of all ART laboratories and is used in many different situations — often used to guarantee fertilization, even in cases where male factor is not an indication for treatment — or where there has been previous poor or total failure of fertilization, even with seemingly normal semen parameters. Some laboratories utilize ICSI for all first time IVF cycles and in instances of “unknown” infertility parameters. The current feeling is that ICSI is an inherently safe procedure and that the resulting offspring appear normal in every respect. Abnormalities (such as increased sex chromosome abnormalities) arise from the use of abnormal sperm rather than the technical procedure itself. The timing of ICSI has often been debated. Should it be performed at about the same time that standard insemination occurs? Earlier? Later? When is the oocyte ready to receive the sperm? The events leading up to the formation of the mature oocyte may help answer this question. (Read More)