Angiogenesis in day-30 bovine pregnancies derived from nuclear transfer.

Impaired placental angiogenesis during early pregnancy may result in placental defects that adversely affect development of nuclear-transfer (NT) embryos later in pregnancy. These experiments were designed to quantify and compare development of placental microvasculature and expression of genes associated with angiogenesis, including members of the VEGF and angiopoietin (Ang) families, in maternal and embryonic placental tissues of day 30 bovine concepti derived from NT or in vitro fertilization (IVF) followed by in vivo development to the blastocyst stage in the sheep oviduct. Microvascular volume density (MVD) within the caruncular tissues, as determined using Periodic Acid-Schiff's staining as well as immunohistochemical staining for von Willebrand's factor, was not different between NT- and IVF- derived pregnancies.

Perinatal physiology in cloned and normal calves: hematologic and biochemical profiles.

Although a majority of clones are born normal and apparently healthy, mortality rates of nearly 30% are described in many reports. Such losses are a major limitation of cloning technology and represent substantial economic investment as well as justifiable animal health and welfare concerns. Prospective, controlled studies are needed to understand fully the causes of neonatal mortality in clones and to develop preventive and therapeutic strategies to minimize losses.

Perinatal physiology in cloned and normal calves: physical and clinical characteristics.

The period immediately after birth is a vital time for all newborn calves as the cardiovascular, respiratory, and other organ systems adapt to life ex utero. Reported neonatal mortality rates suggest this period to be especially critical in cloned calves; yet prospective, controlled studies on the physiological status of these calves are lacking. The objectives of this study were to compare neonatal (birth to 48 h of age) physical and clinical characteristics and placental morphology of cloned and embryo transfer control calves delivered by cesarean section after induced labor.

Early pancreas transplant outcomes with histidine-tryptophan-ketoglutarate preservation: a multicenter study.

Little is known about the use of histidine-tryptophan-ketoglutarate (HTK) preservation solution for pancreas preservation. We compared early pancreas graft outcomes at four pancreas transplant programs within the state of Michigan in 2002 and 2003 (University of Wisconsin [UW] era) with those in 2004 (HTK era). The primary endpoint was early graft loss.

Single center review of femoral arteriovenous grafts for hemodialysis.

Introduction: It is unclear how to manage high risk hemodialysis patients who present with an indwelling catheter. The National Kidney Foundation Practice Guidelines urge prompt removal of the catheter, but the guidelines do not specifically address the problem of patients whose only option is a femoral arteriovenous (AV) graft.

Methods: This study was a retrospective review of all patients who underwent femoral AV graft placement for hemodialysis access between January 1, 1996 and January 1, 2003 at the University of Michigan Health System (UMHS).

Measures of maternal-fetal interaction in day-30 bovine pregnancies derived from nuclear transfer.

Embryonic mortality and abnormal placental morphology have been reported by most researchers studying nuclear transfer (NT), and it now is accepted that placental anomalies and poor development of cloned embryos are related. As early as day 50 of gestation, cloned bovine concepti exhibit poor structural organization of the developing placentomes. These experiments were designed to identify alterations in maternal-fetal interactions during establishment of the placentas of NT-derived embryos at day 30 of gestation.

Effect of the nuclear-donor cell lineage, type, and cell donor on development of somatic cell nuclear transfer embryos in cattle.

Potential applications of somatic cell nuclear transfer to agriculture and medicine are currently constrained by low efficiency and high rates of embryonic, fetal, and neonatal loss. Nuclear transfer efficiency in cattle was compared between three donor-cell treatments from a single animal, between four donor-cell treatments in sequential stages of differentiation from a single cell lineage and genotype, and between the same cell type in two donors. Cumulus and granulosa donor cells resulted in a greater proportion of viable day-7 embryos than ear-skin cells; pregnancy rate and losses were not different among treatments.

Attempts to enhance production of porcine chimeras from embryonic germ cells and preimplantation embryos.

Porcine embryonic germ (EG) cells share common features with porcine embryonic stem (ES) cells, including morphology, alkaline phosphatase activity and capacity for in vitro differentiation. Porcine EG cells are also capable of in vivo development by producing chimeras after blastocyst injection; however, the proportion of injected embryos that yield a chimera and the proportion of cells contributed by the cultured cells in each chimera are too low for practical use in genetic manipulation. Moreover, somatic, but not germ-line chimerism, has been reported from blastocyst injection using porcine ES or EG cells.

Increased efficiency of transgenic livestock production.

Production of transgenic livestock by pronuclear microinjection of DNA into fertilized zygotes suffers from the compounded inefficiencies of low embryo survival and low integration frequencies of the injected DNA into the genome. These inefficiencies are one of the major obstacles to the large-scale use of pronuclear microinjection techniques in livestock. We investigated exploiting the properties of recombinase proteins that allow them to bind DNA to generate transgenic animals via pronuclear microinjection.

Growth, development, and gene expression by in vivo- and in vitro-produced day 7 and 16 bovine embryos.

The effects of the embryo production system on growth and transcription rate of day 7 and 16 bovine embryos were investigated. In vivo- (controls) and in vitro-produced (IVP) embryos were transferred to female recipients on day 7 of development, and were allowed to develop in a synchronous uterine environment to day 16. Embryonic transcripts for insulin-like growth factors-1 and -2 (IGF-1 and -2), their receptors (IGF-1r and -2r), facilitative glucose transporters-1 and -3 (Glut-1 and -3), and interferon-tau (IFN-tau) were determined by real-time quantitative PCR (TaqMan); gender diagnosis was performed on day 16 concepti only.

Morphology and morphometry of in vivo- and in vitro-produced bovine concepti from early pregnancy to term and association with high birth weights.

This study was designed to characterize conceptus development based on pre- and postnatal measurements of in vivo- and in vitro-derived bovine pregnancies. In vivo-produced embryos were obtained after superovulation, whereas in vitro-produced embryos were derived from established procedures for bovine IVM, IVF and IVC. Blastocysts were transferred to recipients to obtain pregnancies of single (in vivo/singleton or in vitro/singleton groups) or twin fetuses (in vitro/twins group).