Michael C. Summers
Harvard University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Michael C. Summers.
Fertility and Sterility | 2008
John D. Biggers; Michael C. Summers
OBJECTIVE To analyze critically the reasons justifying the choice of two-step protocols requiring two media for the culture of human preimplantation embryos from the zygote to the blastocyst. DESIGN Literature review. RESULT(S) Two types of protocol are used for the culture of human preimplantation embryos from the zygote to the blastocyst, using either one medium (one-step protocol) or two media of different composition (two-step protocol). Two-step protocols are the most widely used, largely because all but one of the commercially available protocols are of this type. The reasons for the adoption of two-step protocols are described and critically analyzed. They are based on considerations of the functions of glucose, ethylenediaminetetraacetic acid (EDTA), glutamine, and amino acids that are included in the media. A reappraisal of the reasons for selecting two-step protocols is important because recent animal experiments and clinical observations have raised doubts as to whether the more complex, two-step protocols have any advantage over one-step protocols. The analyses show that all of conclusions reached should be considered equivocal. CONCLUSION(S) Clinical embryologists should evaluate the justification for selecting two-step protocols for the culture of human preimplantation embryos from the zygote to the blastocyst.
Reproductive Biomedicine Online | 2004
John D. Biggers; Lynda K. McGinnis; Michael C. Summers
A review of the literature shows divergent differences between laboratories of the effects of glutamine in mouse preimplantation embryo culture media. One laboratory reported several cases of exencephaly, which was attributed to ammonia produced by the breakdown of glutamine. Two other laboratories have found no such effects. It is suggested, but not proved, that the differences in results may have a genetic basis. Further, it is argued that studies on the toxicological actions of exogenous ammonium chloride on preimplantation development provide a biased model of the effects of glutamine as used in embryo culture protocols. The finding that ammonium can also cause exencephaly thus fosters undue concern about the teratological effects of glutamine.
Human Reproduction Update | 2003
Michael C. Summers; John D. Biggers
Biology of Reproduction | 1995
Michael C. Summers; Piyush R. Bhatnagar; Joel Lawitts; John D. Biggers
Human Reproduction | 2000
Michael C. Summers; Lynda K. McGinnis; Joel Lawitts; Michael Raffin; John D. Biggers
Human Reproduction Update | 1997
John D. Biggers; Michael C. Summers; Lynda K. McGinnis
Human Reproduction | 2005
Michael C. Summers; Lynda K. McGinnis; Joel Lawitts; John D. Biggers
Human Reproduction | 2006
John D. Biggers; Lynda K. McGinnis; Michael C. Summers
Human Reproduction | 2008
John D. Biggers; Michael C. Summers
Reproductive Biomedicine Online | 2012
Sophie Bird; Michael C. Summers; Fatima Mirzazadeh; Christian Ottolini; Lourdes Muriel Rios; Shaun Rogers; J. Taylor; Alan R. Thornhill; John D. Biggers