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Invited Commentary On: Orthotopic Heart Transplantation In Patients With Metabolic Risk Factors, Nicholas Cavarocchi, Paul Mather

Nicholas C Cavarocchi MDJ

This is invited commentary to the following article: Kilic, A., Conte, J. V., Shah, A. S., & Yuh, D. D. (2012). Orthotopic heart transplantation in patients with metabolic risk factors. Annals of Thoracic Surgery, 93(3), 718-724.

Determination Of Cutpoints For Low And High Number Of Symptoms In Patients With Advanced Cancer, Stephanie Gilbertson-White, B. Aouizerat, T. Jahan, S. Paul, C. West, K. Schumacher, M. Dodd, M. Rabow, A. Abu Raddaha, C. Miaskowski

Stephanie Gilbertson-White

While patients with advanced cancer experience a wide range of symptoms, no work has been done to determine an optimal cutpoint for a low versus a high number of symptoms. Analytic approaches that established clinically meaningful cutpoints for the severity of cancer pain and fatigue provided the foundation for this study. The purpose of this study was to determine the optimal cutpoint for low and high numbers of symptoms using a range of potential cutpoints and to determine if those cutpoints distinguished between the two symptom groups on demographic and clinical characteristics and depression, anxiety, and quality of life (QOL). …

Documentation On Withdrawal Of Life Support In Adult Patients In The Intensive Care Unit [Corrected] [Published Erratum Appears In Am J Crit Care 2004 Sep;13(5):370], K. Kirchhoff, P. Anumandla, K. Foth, S. Lues, Stephanie Gilbertson-White

Stephanie Gilbertson-White

BACKGROUND: Patients' charts have been a source of data for retrospective studies of the quality of end-of-life care. In the intensive care unit, most patients die after withdrawal of life support. Chart reviews of this process could be used not only to assess the quality of documentation but also to provide information for quality improvement and research. OBJECTIVE: To assess the documentation of end-of-life care of patients and their families by care providers in the intensive care unit. METHOD: Charts of 50 adult patients who died in the intensive care unit at a large midwestern hospital after initiation of withdrawal …

The Association Between Hospital Obstetrical Volume And Maternal Postpartum Complications, Kathy Kyser, Xin Lu, Donna Santillan, Mark Santillan, Stephen Hunter, Alison Cahill, Peter Cram

Stephen K. Hunter

OBJECTIVE: The purpose of this study was to examine the relationship between delivery volume and maternal complications. STUDY DESIGN: We used administrative data to identify women who had been admitted for childbirth in 2006. Hospitals were stratified into deciles that were based on delivery volume. We compared composite complication rates across deciles. RESULTS: We evaluated 1,683,754 childbirths in 1045 hospitals. Decile 1 and 2 hospitals had significantly higher rates of composite complications than decile 10 (11.8% and 10.1% vs 8.5%, respectively; P < .0001). Decile 9 and 10 hospitals had modestly higher composite complications as compared with decile 6 (8.8% and …

Development And Characterization Of A Severe Acute Respiratory Syndrome-Associated Coronavirus-Neutralizing Human Monoclonal Antibody That Provides Effective Immunoprophylaxis In Mice, Thomas Greenough, Gregory Babcock, Anjeanette Roberts, Hector Hernandez, William Thomas, Jennifer Coccia, Robert Graziano, Mohan Srinivasan, Israel Lowy, Robert Finberg, Kanta Subbarao, Leatrice Vogel, Mohan Somasundaran, Katherine Luzuriaga, John Sullivan, Donna Ambrosino

William D Thomas Jr

BACKGROUND: Severe acute respiratory syndrome (SARS) remains a significant public health concern after the epidemic in 2003. Human monoclonal antibodies (MAbs) that neutralize SARS-associated coronavirus (SARS-CoV) could provide protection for exposed individuals. METHODS: Transgenic mice with human immunoglobulin genes were immunized with the recombinant major surface (S) glycoprotein ectodomain of SARS-CoV. Epitopes of 2 neutralizing MAbs derived from these mice were mapped and evaluated in a murine model of SARS-CoV infection. RESULTS: Both MAbs bound to S glycoprotein expressed on transfected cells but differed in their ability to block binding of S glycoprotein to Vero E6 cells. Immunoprecipitation analysis revealed …

Treatment With Monoclonal Antibodies Against Clostridium Difficile Toxins, Israel Lowy, Deborah Molrine, Brett Leav, Barbara Blair, Roger Baxter, Dale Gerding, Geoffrey Nichol, William Thomas, Mark Leney, Susan Sloan, Catherine Hay, Donna Ambrosino

William D Thomas Jr

BACKGROUND: New therapies are needed to manage the increasing incidence, severity, and high rate of recurrence of Clostridium difficile infection.

METHODS: We performed a randomized, double-blind, placebo-controlled study of two neutralizing, fully human monoclonal antibodies against C. difficile toxins A (CDA1) and B (CDB1). The antibodies were administered together as a single infusion, each at a dose of 10 mg per kilogram of body weight, in patients with symptomatic C. difficile infection who were receiving either metronidazole or vancomycin. The primary outcome was laboratory-documented recurrence of infection during the 84 days after the administration of monoclonal antibodies or placebo.

RESULTS: …

Therapy With A Severe Acute Respiratory Syndrome-Associated Coronavirus-Neutralizing Human Monoclonal Antibody Reduces Disease Severity And Viral Burden In Golden Syrian Hamsters, Anjeanette Roberts, William Thomas, Jeannette Guarner, Elaine Lamirande, Gregory Babcock, Thomas Greenough, Leatrice Vogel, Norman Hayes, John Sullivan, Sherif Zaki, Kanta Subbarao, Donna Ambrosino

William D Thomas Jr

BACKGROUND: Immunotherapy with monoclonal antibodies (MAbs) offers safe interventions for the prevention of infection in patients after organ transplantation and for the treatment of cancers and autoimmune diseases. MAb 201 is a severe acute respiratory syndrome-associated coronavirus (SARS-CoV)-specific MAb that prevents establishment of viral replication in vitro and prevents viral replication in vivo when administered prophylactically. The efficacy of MAb 201 in the treatment of SARS was evaluated in golden Syrian hamsters, an animal model that supports SARS-CoV replication to high levels and displays severe pathological changes associated with infection, including pneumonitis and pulmonary consolidation. METHODS: Golden Syrian hamsters that …

Lineage-Specific T-Cell Responses To Cancer Mucosa Antigen Oppose Systemic Metastases Without Mucosal Inflammatory Disease., Adam Snook, Peng Li, Benjamin J Stafford, Elizabeth J Faul, Lan Huang, Ruth C Birbe, Alessandro Bombonati, Stephanie Schulz, Matthias Schnell, Laurence Eisenlohr, Scott Waldman

Adam E Snook

Cancer mucosa antigens are emerging as a new category of self-antigens expressed normally in immunologically privileged mucosal compartments and universally by their derivative tumors. These antigens leverage the established immunologic partitioning of systemic and mucosal compartments, limiting tolerance opposing systemic antitumor efficacy. An unresolved issue surrounding self-antigens as immunotherapeutic targets is autoimmunity following systemic immunization. In the context of cancer mucosa antigens, immune effectors to self-antigens risk amplifying mucosal inflammatory disease promoting carcinogenesis. Here, we examined the relationship between immunotherapy for systemic colon cancer metastases targeting the intestinal cancer mucosa antigen guanylyl cyclase C (GCC) and its effect on inflammatory …

Developing An Artificial Fallopian Tube: Successful In Vitro Trials In Mice., Stephen Hunter, J. Neeld, J. Scott, D. Olsen, R. Urry, T. Cichocki

Stephen K. Hunter

This report describes the design and testing of an artificial fallopian tube for the treatment of tubal infertility. Within the device, mouse eggs incubated with sperm were fertilized and a microinfusion pump was used to transport the fertilized ova through the tube. Normal offspring resulted from transfer of the developing embryos into pseudopregnant recipients. These results provide encouraging evidence that an artificial fallopian tube warrants further investigation as a potential alternative to in vitro fertilization.

The Gamete And Embryo Compatibility Of Various Synthetic Polymers., Stephen Hunter, J. Scott, D. Hull, R. Urry

Stephen K. Hunter

Several popular and well-characterized polymeric materials were evaluated for their biocompatibility toward the cells unique to reproduction. To accomplish these studies, several in vitro tests were developed that evaluated biocompatibility between the polymers and spermatozoa, ova, and embryos. The data indicated significant differences between the materials with respect to their biocompatibility toward sperm motility, the sperm's ability to penetrate zona-free hamster eggs, and the ability of two-cell mouse embryos to divide. Polytetrafluoroethylene (PTFE-Teflon; PTFE, Chemplast Inc., Wayne, NJ), polyethylene glycol (PEG), and polyhydroxyethyl methacrylate (PHEMA) appear to be the most inert of the materials studied. Polyvinyl chloride (PVC; Tygon-Norton, Akron, …

Surface Modification Of Polyurethane To Promote Long-Term Patency Of Peritoneal Access Devices., Stephen Hunter, D. Gregonis, D. Coleman, B. Hanover, R. Stephen, S. Jacobsen

Stephen K. Hunter

No abstract provided.

Cell Encapsulation As A Potential Nondietary Therapy For Maternal Phenylketonuria, Donna Santillan, Mark Santillan, Stephen Hunter

Stephen K. Hunter

OBJECTIVE: The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria. STUDY DESIGN: Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry. RESULTS: Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly …

A Mouse Model For Beta 0-Thalassemia., Baoli Yang, S. Kirby, J. Lewis, P. Detloff, N. Maeda, O. Smithies

Baoli Yang

We have used a "plug and socket" targeting technique to generate a mouse model of beta 0-thalassemia in which both the b1 and b2 adult globin genes have been deleted. Mice homozygous for this deletion (Hbbth-3/Hbbth-3) die perinatally, similar to the most severe form of Cooley anemia in humans. Mice heterozygous for the deletion appear normal, but their hematologic indices show characteristics typical of severe thalassemia, including dramatically decreased hematocrit, hemoglobin, red blood cell counts, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration, as well as dramatically increased reticulocyte counts, serum bilirubin concentrations, and red cell distribution …

Appropriate Tissue- And Cell-Specific Expression Of A Single Copy Human Angiotensinogen Transgene Specifically Targeted Upstream Of The Hprt Locus By Homologous Recombination., B. Cvetkovic, Baoli Yang, R. Williamson, C. Sigmund

Baoli Yang

Development of experimental models by genetic manipulation in mice has proven to be very useful in determining the significance of particular genes in the development of or susceptibility to hypertension. Advances in molecular genetics, transgenic mouse technology, and physiological measurements in mice provided an opportunity to go a step further and develop models to analyze the physiological significance of specific gene variants potentially causing hypertension. In this report, we describe the development of a human angiotensinogen transgenic mouse model generated by targeting the human angiotensinogen gene upstream of the mouse HPRT locus by homologous recombination. The main benefit of this …

Chymase Inhibition Prevents Fibronectin And Myofibrillar Loss And Improves Cardiomyocyte Function And Lv Torsion Angle In Dogs With Isolated Mitral Regurgitation., Betty Pat, Yuanwen Chen, Cheryl Killingsworth, James D Gladden, Ke Shi, Junying Zheng, Pamela C Powell, Greg Walcott, Mustafa I Ahmed, Himanshu Gupta, Ravi Desai, Chih-Chang Wei, Naoki Hase, Tsunefumi Kobayashi, Abdelkarim Sabri, Henk Granzier, Thomas Denney, Michael Tillson, A Ray Dillon, Ahsan Husain, Louis J Dell'italia

Ravi V Desai MD

BACKGROUND: The left ventricular (LV) dilatation of isolated mitral regurgitation (MR) is associated with an increase in chymase and a decrease in interstitial collagen and extracellular matrix. In addition to profibrotic effects, chymase has significant antifibrotic actions because it activates matrix metalloproteinases and kallikrein and degrades fibronectin. Thus, we hypothesize that chymase inhibitor (CI) will attenuate extracellular matrix loss and LV remodeling in MR.

METHODS AND RESULTS: We studied dogs with 4 months of untreated MR (MR; n=9) or MR treated with CI (MR+CI; n=8). Cine MRI demonstrated a >40% increase in LV end-diastolic volume in both groups, consistent with …

Managed Care, Hospice Use, Site Of Death, And Medical Expenditures In The Last Year Of Life, Ezekiel Emanuel, Arlene Ash, Wei Yu, Gail Gazelle, Norman Levinsky, Olga Saynina, Mark Mcclellan, Mark Moskowitz

wei yu

BACKGROUND: We examined deaths of Medicare beneficiaries in Massachusetts and California to evaluate the effect of managed care on the use of hospice and site of death and to determine how hospice affects the expenditures for the last year of life.

METHODS: Medicare data for beneficiaries in Massachusetts (n = 37 933) and California (n = 27 685) who died in 1996 were merged with each state's death certificate files to determine site and cause of death. Expenditure data were Health Care Financing Administration payments and were divided into 30-day periods from the date of death back 12 months.

RESULTS: …

The Association Between Hospital Obstetrical Volume And Maternal Postpartum Complications., Kathy L Kyser, Xin Lu, Donna Santillan, Mark Santillan, Stephen Hunter, Alison G Cahill, Peter Cram

Donna A. Santillan

OBJECTIVE: The purpose of this study was to examine the relationship between delivery volume and maternal complications.

STUDY DESIGN: We used administrative data to identify women who had been admitted for childbirth in 2006. Hospitals were stratified into deciles that were based on delivery volume. We compared composite complication rates across deciles.

RESULTS: We evaluated 1,683,754 childbirths in 1045 hospitals. Decile 1 and 2 hospitals had significantly higher rates of composite complications than decile 10 (11.8% and 10.1% vs 8.5%, respectively; P < .0001). Decile 9 and 10 hospitals had modestly higher composite complications as compared with decile 6 (8.8% and 8.5% vs 7.6%, respectively; P < .0001). Sixty percent of decile 1 and 2 hospitals were located within 25 miles of the nearest greater volume hospital.

CONCLUSION: Women who deliver at very low-volume hospitals have higher complication rates, as do women who deliver at …

From Molecules To Medicine: A Future Cure For Preeclampsia?, Mark Santillan, Donna Santillan, Curt Sigmund, Stephen Hunter

Donna A. Santillan

In the United States, preeclampsia (PreE) affects 5-7% of all pregnancies, yet represents 15% of all maternal-fetal morbidity and mortality. PreE causes fetal growth restriction, oligohydramnios, fetal death, and maternal seizures, stroke, cerebrovascular hemorrhage and death. It has immediate and potentially long-term effects on both the fetus and mother. To date, the molecular pathogenesis of PreE is largely unknown. Multiple pathways, including dysfunctional angiogenesis, inappropriate placentation, oxidative stress and an altered immunological milieu have been proposed as key players in the development of PreE. In addition, genetic factors in all of these pathways are essential components in the etiology of …

Noninvasive Whole-Genome Sequencing Of A Human Fetus, J. Kitzman, M. Snyder, M. Ventura, A. Lewis, R. Qiu, L. Simmons, H. Gammill, C. Rubens, Donna Santillan, J. Murray, H. Tabor, M. Bamshad, E. Eichler, J. Shendure

Donna A. Santillan

Analysis of cell-free fetal DNA in maternal plasma holds promise for the development of noninvasive prenatal genetic diagnostics. Previous studies have been restricted to detection of fetal trisomies, to specific paternally inherited mutations, or to genotyping common polymorphisms using material obtained invasively, for example, through chorionic villus sampling. Here, we combine genome sequencing of two parents, genome-wide maternal haplotyping, and deep sequencing of maternal plasma DNA to noninvasively determine the genome sequence of a human fetus at 18.5 weeks of gestation. Inheritance was predicted at 2.8 x 10(6) parental heterozygous sites with 98.1% accuracy. Furthermore, 39 of 44 de novo …

Cell Encapsulation As A Potential Nondietary Therapy For Maternal Phenylketonuria, Donna Santillan, Mark Santillan, Stephen Hunter

Donna A. Santillan

OBJECTIVE: The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria. STUDY DESIGN: Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry. RESULTS: Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly …

Protective Immunization In Mice Against Group B Streptococci Using Encapsulated C5a Peptidase, Donna Santillan, M. E. Andracki, S. K. Hunter

Donna A. Santillan

OBJECTIVE: The purpose of the study was to test whether C5a peptidase encapsulated within a biodegradable polymer can act as a vaccine and elicit an immune response to prevent group B streptococci (GBS) infection in mice and provide protection to pups. STUDY DESIGN: C5a peptidase was encapsulated in semipermeable microspheres of poly(lactide-co-glycolide). Female ICR mice were immunized with encapsulated C5a peptidase, free C5a peptidase, or empty microparticles. Booster doses were given at days 21 and 42. Antibody responses were measured by enzyme-linked immunosorbent assay. Challenge with GBS type III was performed 4 days after the final booster in the vaginal …

Efficacy Of Polymeric Encapsulated C5a Peptidase-Based Group B Streptococcus Vaccines In A Murine Model, Donna Santillan, K. Rai, Mark Santillan, Y. Krishnamachari, A. Salem, S. Hunter

Donna A. Santillan

OBJECTIVE: The purpose was to examine in mice the efficacy of various polymeric-encapsulated C5a peptidase vaccine formulations in eliciting a long-term immune response and preventing group B streptococcus (GBS) infection. STUDY DESIGN: C5a peptidase was encapsulated in semipermeable microspheres of poly(lactide-coglycolide) (PLGA). Female ICR mice were immunized with 0, 10, or 30 mug of encapsulated C5a peptidase within 2 different formulations of PLGA polymers. Booster doses were given at weeks 4 and 8. Antibody responses were measured by enzyme-linked immunosorbent assay at weeks 4, 8, 11, and 40. Vaginal challenges with GBS types 1a, III, and V were performed at …

Cell Encapsulation As A Potential Nondietary Therapy For Maternal Phenylketonuria, Donna Santillan, Mark Santillan, Stephen Hunter

Mark K. Santillan

OBJECTIVE: The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria. STUDY DESIGN: Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry. RESULTS: Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly …

Semen Quality In Fertile Men In Relation To Psychosocial Stress, A. Gollenberg, F. Liu, C. Brazil, E. Drobnis, D. Guzick, J. Overstreet, J. Redmon, Amy Sparks, C. Wang, S. Swan

Amy E.T. Sparks

OBJECTIVE: To examine the association between stressful life events and semen parameters. DESIGN: Cross-sectional analysis in a pregnancy cohort study. SETTING: Prenatal clinics in five U.S. cities. PATIENT(S): Fertile men (n = 744) in the Study for Future Families, a cohort study of pregnant women and their partners. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Sperm concentration, percent motile, and percent normal morphology and classification above/below World Health Organization (WHO) cutoffs for semen quality. RESULT(S): After adjusting for confounders, men reporting 2+ recent stressful life events had an increased risk of being classified below WHO thresholds for "normal" defined by concentration, motility, …

Gene Transfer Efficiency During Gestation And The Influence Of Co-Transfer Of Non-Manipulated Embryos On Production Of Transgenic Mice, R. Canseco, Amy Sparks, R. Page, C. Russell, J. Johnson, W. Velander, R. Pearson, W. Drohan, F. Gwazdauskas

Amy E.T. Sparks

Litter size of DNA microinjected zygotes is lower than for non-manipulated zygotes. The rate of embryonic and fetal survival in early, mid and late gestation was determined to assess whether DNA integration was responsible for embryonic losses. Also, the effect of including non-microinjected embryos with injected embryos on pregnancy rate and transgenic pup production was determined. In Experiment 1, one-cell embryos from immature CD-1 mice were microinjected with a whey acidic protein promoter-human protein C gene construct. One hour after microinjection embryos were transferred to pseudopregnant recipients (45 transfers of 30 embryos each). Fifteen recipients were sacrificed on day 4, …

Psychological Empowerment And Job Satisfaction Between Baby Boomer And Generation X Nurses, Amy Sparks

Amy E.T. Sparks

AIM: This paper is a report of a study of differences in nurses' generational psychological empowerment and job satisfaction. BACKGROUND: Generations differ in work styles such as autonomy, work ethics, involvement, views on leadership, and primary views on what constitutes innovation, quality, and service. METHOD: A secondary analysis was conducted from two data sets resulting in a sample of 451 registered nurses employed at five hospitals in West Virginia. One data set was gathered from a convenience sample and one from a randomly selected sample. Data were collected from 2000 to 2004. RESULTS: Baby Boomer nurses reported higher mean total …

Characterization Of Human Sperm Antigens Reacting With Anti-Sperm Antibodies From An Infertile Female Patient's Serum, H. Feng, Y. Han, Amy Sparks, J. Sandlow

Amy E.T. Sparks

Identification of sperm antigens that elicit immunoglobulin (Ig) production and knowledge of their roles in sperm transport and fertilization may enhance diagnosis and treatment of immunologic infertility. Sperm antigens recognized by a female patient's serum anti-sperm antibodies were characterized using an indirect immunobead-binding test, immunoblot analysis, and immunochemical labeling. The anti-sperm antibodies' effect on sperm function was evaluated by acrosome induction by calcium ionophore. Immunobeads specific for IgG were bound to the head of 79% of motile donor sperm. Immunochemical labeling of antibody-binding sites was restricted to the plasma membrane over the acrosomal crescent. No labeling was observed on the …

Social Cognition, Empathy And Functional Outcome In Schizophrenia, Amy Sparks, S. Mcdonald, B. Lino, M. O'Donnell, M. Green

Amy E.T. Sparks

Social and occupational functioning difficulties are a characteristic feature of schizophrenia, and a growing body of evidence suggests that deficits in social cognition contribute significantly to these functional impairments. The present study sought to investigate whether the association between social cognition and social functioning in schizophrenia would be mediated by self-reported levels of empathy. Thirty outpatients with a diagnosis of schizophrenia or schizoaffective disorder, and twenty-five healthy controls completed a well-validated facial affect processing task (Ekman 60-faces facial task from the Facial Expressions of Emotion - Stimuli and Tests; FEEST), The Awareness of Social Inference Test (TASIT; to assess emotion …

Development Of An Immunocontraceptive Vaccine. Current Status, H. Feng, J. Sandlow, Amy Sparks, A. Sandra

Amy E.T. Sparks

Development of an effective and modern contraceptive vaccine is a key factor in the global issue of regional population growth as well as agricultural, medical, economic and social development. A review was done of the current medical literature concerning development of an immunocontraceptive vaccine and relative molecular biology technology. Various approaches have been taken to identify candidate-specific antigens for immunocontraceptive development, such as sperm, zona pellucida and hormonal antigens. Suppressed fertility and the reversibility of these effects on mammalian species, including humans, have been demonstrated. The successful results obtained so far support the continued investigation for an effective immunocontraceptive vaccine.

Culture Systems: Embryo Culture And Monozygotic Twinning, Amy Sparks

Amy E.T. Sparks

The incidence of monozygotic twinning in pregnancies achieved with assisted reproductive technologies (ART) is significantly higher than spontaneously conceived pregnancies. The factors associated with ART that predispose the embryos to splitting are not well-characterized. Assisted hatching and extended embryo culture are two ART laboratory methods that have been risk factors for monozygotic twinning. The methods and strategies that may be employed to avoid monozygotic twinning are discussed in this chapter.