Embryo Project Encyclopedia Articles

In 2015, biologist Helena D. Zomer and colleagues published the review article “Mesenchymal and Induced Pluripotent Stem Cells: General Insights and Clinical Perspectives” or “Mesenchymal and Induced Pluripotent Stem Cells” in Stem Cells and Cloning: Advances and Applications. The authors reviewed the biology of three types of pluripotent stem cells, embryonic stem cells, or ESCs, mesenchymal stem cells, or MSCs, and induced pluripotent stem cells, or iPS cells. Pluripotent stem cells are a special cell type that can give rise to other types of cells and are essential for development. The authors describe the strengths and weaknesses of each type of stem cell for regenerative medicine applications. They state that both MSC and iPS types of stem cells have the potential to regenerate tissues among many other therapeutic possibilities. In their article, Zomer and colleagues review the potential for MSCs and iPS cells to reshape the field of regenerative and personal medicine.

In 2017, Angiolo Gadducci, Silvestro Carinelli, and Giovanni Aletti published, "Neuroendocrine Tumor of the Uterine Cervix: A Therapeutic Challenge for Gynecologic Oncologists," hereafter, "Neuroendocrine Tumor" in the journal, Gynecologic Oncology. The authors conducted a systematic review of existing literature that documented the symptoms, diagnosis, staging, treatment, and outcomes of women diagnosed with neuroendocrine tumors, or cervical NETs, which are tumors with cells similar to cells from both the hormonal and the nervous system. Based on high mortality rates and the rarity of cervical NET diagnoses, the authors conclude that cervical NETs present a challenge for physicians in terms of devising novel ideas for treatment. By compiling the treatment methods and resulting outcomes of different studies, the authors presented evidence that there is a need for new forms of treatment to reduce the number of women dying from cervical NETs each year.

During the 1870s and early 1880s, the British morphologist Francis Maitland Balfour contributed in important ways to the budding field of evolutionary embryology, especially through his comparative embryological approach to uncovering ancestral relationships between groups. As developmental biologist and historian Brian Hall has observed, the field of evolutionary embryology in the nineteenth century was the historical ancestor of modern-day evolutionary developmental biology. Balfour's work was notably inspired by Charles Darwin's theory of evolution and Ernst Haeckel's account of the relationships between embryology and evolution. Only a decade after Balfour's program of research began, an alpine climbing accident robbed Britain of its most promising embryologist.

Aristotle studied developing organisms, among other things, in ancient Greece, and his writings shaped Western philosophy and natural science for greater than two thousand years. He spent much of his life in Greece and studied with Plato at Plato's Academy in Athens, where he later established his own school called the Lyceum. Aristotle wrote greater than 150 treatises on subjects ranging from aesthetics, politics, ethics, and natural philosophy, which include physics and biology. Less than fifty of Aristotle's treatises persisted into the twenty-first century. In natural philosophy, later called natural science, Aristotle established methods for investigation and reasoning and provided a theory on how embryos generate and develop. He originated the theory that an organism develops gradually from undifferentiated material, later called epigenesis.

Vasovasostomy is a microsurgical procedure to restore fertility after vasectomy, a surgery that sterilizes the patient by severing the vas deferentia, the tubes that carry the sperm from the testes to the penis. After a vasectomy, a patient may have various reasons for wanting to reverse the procedure, such as new opportunities for having children or a new romantic partnership. A vasovasostomy involves reestablishing the flow of sperm through the vas deferens by reconnecting the severed ends of the tube. In 1919, in the United States, William C. Quinby performed the first recorded successful vasovasostomy. Modern improvements on the surgery have led to its adoption as a microsurgery, a procedure that involves a microscope and specialized microscopic instruments. Surgical research over the twentieth century into reconnecting a blocked vas deferens and the resulting microsurgical technique for vasovasostomy has provided a way for people to regain their fertility after a vasectomy.

No-scalpel vasectomy, or NSV or keyhole vasectomy, is a surgical method of sterilization that involves puncturing the skin of the scrotum to access the vas deferens, a tube that carries spermatozoa, or sperm, from the testes to the penis. The surgeon performing the procedure blocks the flow of sperm through the vas deferens, sterilizing the patient. NSV is a less invasive procedure, as it does not use a scalpel to make a deep cut on sensitive scrotal tissue. Typically, urologists perform NSV with the purpose of rendering the patient sterile while not altering other functions of the testes, scrotum, and penis. Li Shunqiang developed the technique in China in 1974 as a less invasive method of vasectomy for male patients. Li’s development of NSV provided an alternative method to vasectomies that rely on making incisions into the scrotum with a blade. NSV gained wide use as a sterilization technique, providing a path for males to take greater responsibility for contraception and family planning.

Harry Clay Sharp was a surgeon who performed one of the first recorded vasectomies with the purpose of sterilizing a patient. Sterilization is the practice that makes a person unable to reproduce, and vasectomy accomplishes that by severing the vasa deferentia, the sperm-carrying tubes in the male reproductive system. Historically, sterilization procedures have varied in techniques, goals, and risks, but Sharp’s method of vasectomy allowed restriction of a patient’s reproductive functions without significantly affecting other bodily functions. Historians have associated Sharp’s use of the procedure, primarily on prison inmates, with eugenics, a movement with the goal of bettering humans via selective reproductive practices. With vasectomy, Sharp was able to sterilize people whom he did not deem fit to reproduce. Beyond simply pushing forward a new surgical method of sterilization, Sharp’s political advocacy led to the use of his technique as a method of eugenicist control over human reproduction, especially in Indiana.

In 1962 the journal Acta Biotheoretica published the final work of the biologist Edward Stuart Russell, a full eight years after his death. Entitled The Diversity of Animals: an Evolutionary Study, this short, unfinished manuscript on evolution received little recognition in the scientific presses despite both its technical discussion of adaptations in decapods (crabs, shrimp, etc.) and its different approach to evolutionary theory. The precise reason for this neglect is unclear. This book is a continuation of Russell's philosophical perspective, organicism, an interpretation that focuses on the organism as the primary unit of analysis for the biological sciences. Russell first argued for this position in several of his earlier works, such as The Interpretation of Development and Heredity (1930) and The Directiveness of Organic Activities (1946). What was new in The Diversity of Animals lies in Russell's orthogenetic theory of evolution. By "orthogenetic" he means evolutionary change in definite directions. The overall thesis of this work is that transformations in evolution that occur in early ontogenesis, or development, are the best explanation for most diversity in nature. The consequence of Russell's argument is that an understanding of development is fundamental to an explanation of the major transformations in the evolutionary history of life.