Susan E. Lanzendorf

Bio: Susan E. Lanzendorf is an academic researcher from Eastern Virginia Medical School. The author has contributed to research in topics: Sperm & Oocyte. The author has an hindex of 23, co-authored 47 publications receiving 2012 citations.

Evaluation of the spindle apparatus of in-vitro matured human oocytes following cryopreservation

Abstract: The present study was conducted to determine if the cryopreservation of immature human oocytes has a deleterious effect on the meiotic spindle following maturation in vitro. Oocytes were obtained in excess from in-vitro fertilization patients and divided into four groups. Groups 1 (n = 98) and 2 (n = 80) consisted of immature oocytes cryopreserved before or after maturation in vitro respectively. Groups 3 (n = 37) and 4 (n = 9) served as non-frozen controls and included oocytes matured in vitro and in vivo respectively. The meiotic spindle was identified after incubation in anti-tubulin monoclonal antibody (1 h, 37 degrees C) and fluorescein-conjugated goat anti-mouse immunoglobulin G (IgG) (1 h, RT). Chromosomes were counterstained with 4',6'-diamidino-2-phenylindole. Following cryopreservation, group 1 oocytes demonstrated a 63% survival rate and 68% maturation rate in vitro. In all, 58% of the oocytes in group 2 survived the thaw. The number of oocytes with normal spindles in group 1 (81.0%) was not significantly different from control groups 3 (83.8%) and 4 (88.9%), while the number of group 2 oocytes with normal structures (43.5%) was significantly lower than groups 1 (P = 0.0004), 3 (P = 0.0002), and 4 (P = 0.025). These results suggest that cryopreservation of the prophase I human oocyte does not significantly increase abnormalities in the resulting meiotic spindle.

Expression of mRNAs for DNA methyltransferases and methyl-CpG-binding proteins in the human female germ line, preimplantation embryos, and embryonic stem cells.

Abstract: Recent evidence indicates that mammalian gametogenesis and preimplantation development may be adversely affected by both assisted reproductive and stem cell technologies. Thus, a better understanding of the developmental regulation of the underlying epigenetic processes that include DNA methylation is required. We have, therefore, monitored the expression, by PCR, of the mRNAs of DNA methyltransferases (DNMTs), methyl-CpG-binding domain proteins (MBDs), and CpG binding protein (CGBP) in a developmental series of amplified cDNA samples derived from staged human ovarian follicles, oocytes, preimplantation embryos, human embryonic stem (hES) cells and in similar murine cDNA samples. Transcripts of these genes were detected in human ovarian follicles (DNMT3A, DNMT3b1, DNMT3b4, DNMT1, MDBs1–4, MeCP2, CGBP), germinal vesicle (GV) oocytes (DNMT3A, DNMT3b1, DNMT1, MDBs1–4, MeCP2, CGBP), mature oocytes (DNMT3A, DNMT3b1, DNMT1, CGBP), and preimplantation embryos (DNMT3A, DNMT3b1, DNMT1, DNMT3L, MBD2, MDB4, CGBP). Differential expression of DNMT3B gene transcripts in undifferentiated (DNMT3b1) and in vitro differentiated human ES cells (DNMT3b3) further demonstrated an association of the DNMT3b1 transcript variant with totipotent and pluripotent human cells. Significantly, whilst the murine Dnmt3L gene is both expressed and essential for imprint establishment during murine oogenesis, transcripts of the human DNMT3L gene were only detected after fertilisation. Therefore, the mechanisms and/or the timing of imprint establishment may differ in humans. Mol. Reprod. Dev. 67: 323–336, 2004. © 2004 Wiley-Liss, Inc.

High fertilization and implantation rates after intracytoplasmic sperm injection

Abstract: Previously reported better fertilization rate after intracytoplasmic single sperm injection (ICSI) than after subzonal insemination of several spermatozoa was confirmed in a controlled comparison of the two procedures in 11 patients. Intracytoplasmic sperm injection was carried out in 150 consecutive treatment cycles of 150 infertile couples, who had failed to have fertilized oocytes after standard in-vitro fertilization (IVF) procedures or who were not accepted for IVF because not enough motile spermatozoa were present in the ejaculate. A single spermatozoon was injected into the ooplasm of 1409 metaphase II oocytes. Only 117 oocytes (8.3%) were damaged by the procedure and 830 oocytes (64.2% of the successfully injected oocytes) had two distinct pronuclei the morning after the injection procedure. The fertilization rate was not influenced by semen characteristics. After 24 h of further in-vitro culture, 71.2% of these oocytes developed into embryos, which were transferred or cryopreserved. Only 15 patients did not have embryos replaced. Three-quarters of the transfers were triple-embryo transfers. High pregnancy rates were noticed since 67 pregnancies were achieved, of which 53 were clinical, i.e. a total and clinical pregnancy rate of 44.7% and 35.3% per started cycle and 49.6% and 39.2% per embryo transfer. A total of 237 supernumerary embryos were cryopreserved in 71 treatment cycles.

Evidence of a Pluripotent Human Embryonic Stem Cell Line Derived from a Cloned Blastocyst

Abstract: Somatic cell nuclear transfer (SCNT) technology has recently been used to generate animals with a common genetic composition. In this study, we report the derivation of a pluripotent embryonic stem (ES) cell line (SCNT-hES-1) from a cloned human blastocyst. The SCNT-hES-1 cells displayed typical ES cell morphology and cell surface markers and were capable of differentiating into embryoid bodies in vitro and of forming teratomas in vivo containing cell derivatives from all three embryonic germ layers in severe combined immunodeficient mice. After continuous proliferation for more than 70 passages, SCNT-hES-1 cells maintained normal karyotypes and were genetically identical to the somatic nuclear donor cells. Although we cannot completely exclude the possibility that the cells had a parthenogenetic origin, imprinting analyses support a SCNT origin of the derived human ES cells.

Time Series—A Biostatistical Introduction

Abstract: (1992). Time Series—A Biostatistical Introduction. Technometrics: Vol. 34, No. 2, pp. 229-230.