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Tissue Engineering
Tissue engineering is a field of regenerative medicine that integrates the knowledge of scientists, physicians, and engineers into the construction or reconstruction of human tissue. Practitioners of tissue engineering seek to repair, replace, maintain, and enhance the abilities of a specific tissue or organ by means of living cells. More often than not stem cells are the form of living cells used in this technology. Tissue engineering is one of the disciplines involved in translating knowledge of developmental biology into the clinical setting.
Format: Articles
Subject: Processes
Hematopoietic Stem Cells
The discovery of hematopoietic stem cells (HSCs) provided a pioneering step in stem cell research. HSCs are a type of multipotent adult stem cell, characterized by their ability to self-renew and differentiate into erythrocyte (red blood cell) and leukocyte (white blood cell) cell lineages. In terms of function, these cells are responsible for the continual renewal of the erythrocytes, leukocytes, and platelets in the body through a process called hematopoiesis. They also play an important role in the formation of vital organs such as the liver and spleen during fetal development.
Format: Articles
Subject: Processes
Somatic Cell Nuclear Transfer in Mammals (1938-2013)
In the second half of the
twentieth century, scientists learned how to clone organisms in some
species of mammals. Scientists have applied somatic cell nuclear transfer to clone human and
mammalian embryos as a means to produce stem cells for laboratory
and medical use. Somatic cell nuclear transfer (SCNT) is a technology applied in cloning, stem cell
research and regenerative medicine. Somatic cells are cells that
have gone through the differentiation process and are not germ
cells. Somatic cells donate their nuclei, which scientists
Format: Articles
Subject: Theories, Technologies, Processes
Ectopic Pregnancy
Many difficulties can arise with a pregnancy even after the sperm successfully fertilizes the oocyte. A major problem occurs if the fertilized egg tries to implant before reaching its normal implantation site, the uterus. An ectopic pregnancy occurs when a fertilized egg implants anywhere other than in the uterus, most commonly in the fallopian tubes. Ectopic pregnancies cannot continue to term, so a physician must remove the developing embryo as early as possible.
Format: Articles
Subject: Disorders, Processes, Reproduction
Umbilical Cord Blood Stem Cells (UCBSC)
Umbilical cord blood (UCB) stem cells are hematopoietic stem cells (HSC) that are recovered from the blood of the umbilical cord and placenta after birth. Umbilical cord blood is rich in cells that express the CD34 molecule, a surface protein that identifies cells as stem cells. Prior to the discovery of UCB stem cells, it was standard procedure to discard the umbilical cord and placenta; now much effort is devoted to raising public awareness and to encouraging people to store or donate cord blood.
Format: Articles
Subject: Processes, Reproduction
Teratomas
Teratomas are embryonal tumors that normally arise from germ cells and are typically benign. They are defined as being composed either of tissues that are foreign to the area in which they form, or of tissues that derive from all three of the germ layers. Malignant teratomas are known as teratocarcinomas; these cancerous growths have played a pivotal role in the discovery of stem cells. "Teratoma" is Greek for "monstrous tumor"; these tumors were so named because they sometimes contain hair, teeth, bone, neurons, and even eyes.
Format: Articles
“Pregnancy Established in an Infertile Patient After Transfer of a Donated Embryo Fertilized In Vitro” (1983), by Alan Trounson, John Leeton, Mandy Besanko, Carl Wood, and Angelo Conti
In 1983, researchers Alan Trounson, John Leeton, Carl Wood, Mandy Besanko, and Angelo Conti published the article “Pregnancy Established in an Infertile Patient After Transfer of a Donated Embryo Fertilized In Vitro” in The British Medical Journal. In the article, the authors discuss one of the first successful experiments using in vitro fertilization, or IVF, with the use of a human donor embryo at the Monash University and Queen Victoria Medical Center in Melbourne, Australia.
Format: Articles
Subject: Publications, Publications, Reproduction, Processes
Regeneration
Regeneration is a fascinating phenomenon. The fact that many organisms have the capacity to regenerate lost parts and even remake complete copies of themselves is difficult to fathom; so difficult, in fact, that for a very long time people were reluctant to believe regeneration actually took place. It seemed unbelievable that some organisms could re-grow lost limbs, organs, and other body parts. If only we could do the same!
Format: Articles
Subject: Processes
“The Prophylactic Forceps Operation” (1920), by Joseph Bolivar DeLee
In 1920, Joseph Bolivar DeLee published the article, “The Prophylactic Forceps Operation,” in which he describes how physicians can manually remove a neonate from a laboring woman’s vagina with the use of sedating drugs and forceps. The procedure, according to DeLee, resulted in decreased rates of complications and mortality for both the woman and neonate. DeLee claimed the procedure could reduce damage to the woman such as prolapse, or when internal pelvic organs push down and sometimes protrude from the vagina, and fatal infant brain bleeding.
Format: Articles
Subject: Publications, Processes
Treatment of Pelvic Organ Prolapse in Women
Pelvic organ prolapse is a common condition in women that causes the pelvic organs to descend, often resulting from a weakened pelvic floor. Pelvic organs supported by the pelvic floor, such as the bladder, bowel, or uterus, can descend to such a degree that they project out from a woman’s body typically via the vagina. Pelvic floor stress or trauma, like vaginal childbirth, can cause pelvic organ prolapse. Women with pelvic organ prolapse also often experience other conditions, such as incontinence or the involuntary leakage of urine or fecal matter.
Format: Articles
Subject: Reproduction, Disorders, Processes
Rh Incompatibility in Pregnancy
Rh incompatibility occurs when a pregnant woman whose blood type is Rh-negative is exposed to Rh-positive blood from her fetus, leading to the mother s development of Rh antibodies. These antibodies have the potential to cross the placenta and attach to fetal red blood cells, resulting in hemolysis, or destruction of the fetus 's red blood cells. This causes the fetus to become anemic, which can lead to hemolytic disease of the newborn. In severe cases, an intrauterine blood transfusion for the fetus may be required to correct the anemia.
Format: Articles
Subject: Processes, Disorders, Reproduction
World Health Organization Guidelines (Option A, B, and B+) for Antiretroviral Drugs to Treat Pregnant Women and Prevent HIV Infection in Infants
To address the international Human Immunodeficiency Virus epidemic, the World Health Organization, or WHO, developed three drug treatment regimens between 2010 and 2012 specifically for HIV-positive pregnant women and their infants. WHO developed the regimens, calling them Option A, Option B, and Option B+, to reduce or prevent mother-to-child, abbreviated MTC, transmission of HIV. Each option comprises of different types and schedules of antiretroviral medications. As of 2018, WHO reported that in Africa alone about 1,200,000 pregnant women were living with untreated HIV.
Format: Articles
Subject: Reproduction, Processes, Disorders
Multi-Fetal Pregnancy
In humans, multi-fetal pregnancy occurs when a mother carries more than one fetus during the pregnancy. The most common multi-fetal pregnancy is twins, but mothers have given birth to up to eight children (octuplets) from a single pregnancy. Multiple fetusus can result from the release of multiple eggs or multiple ovulations, the splitting of a single fertilized egg, and fertility treatments such as in vitro fertilization (IVF) which involves the insertion of many fertilized eggs into the mother's uterus.
Format: Articles
Subject: Processes, Reproduction
Amniocentesis Prior to 1980
The extraembryonic membranes that surround and originate from the embryos of vertebrates such as birds, reptiles, and mammals are crucial to their development. They are integral to increasing the surface area of the uterus, forming the chorion (which in turn produces the placenta) and the amnion, respectively. The amnion will ultimately surround the embryo in a fluid-filled amniotic cavity. This amniotic fluid, which cushions and protects the fetus and helps prevent the onset of labor, is sampled in amniocentesis to screen for genetic diseases.
Format: Articles
Subject: Processes, Reproduction
Human Embryonic Stem Cells
Stem cells are undifferentiated cells that are capable of dividing for long periods of time and can give rise to specialized cells under particular conditions. Embryonic stem cells are a particular type of stem cell derived from embryos. According to US National Institutes of Health (NIH), in humans, the term "embryo" applies to a fertilized egg from the beginning of division up to the end of the eighth week of gestation, when the embryo becomes a fetus. Between fertilization and the eighth week of gestation, the embryo undergoes multiple cell divisions.
Format: Articles
Subject: Processes, Reproduction
Post-Coital Oral Emergency Contraception
Post-coital oral emergency contraception is used for the prevention of pregnancy after intercourse. The contraception comes in the form of pills, often collectively referred to as morning-after pills. Post-coital use of morning-after pills separates them from traditional contraception which is either a continual preventative process, such as the birth control pill, or used during intercourse, such as condoms.
Format: Articles
Subject: Processes, Reproduction
The Effects of Thalidomide on Embryonic Development
Embryogenesis is an intricate process that can easily be disrupted by means of teratogenic agents. Some of these agents target the embryonic period's "window of susceptibility," three to eight weeks after a pregnant woman's last menstruation, when the highest degree of sensitivity to embryonic cell differentiation and organ formation occurs. The embryonic period or critical period is when most organ systems form, whereas the fetal period, week eight to birth, involves the growth and modeling of the organ systems.
Format: Articles
The Yale Embryo
In 1934 a fourteen-day-old embryo was discovered during a postmortem examination and became famous for being the youngest known human embryo specimen at the time. The embryo was coined "the Yale Embryo," named after the location where it was discovered, Yale University in New Haven, Connecticut. During the early twentieth century, the rush to collect embryos as well as to find younger and younger embryos was at an all time high, and the Yale Embryo is representative of the this enthusiasm.
Format: Articles
Subject: Processes, Reproduction
James G. Wilson's Six Principles of Teratology
James Graves Wilson's six principles of teratology, published in 1959, guide research on teratogenic agents and their effects on developing organisms. Wilson's six principles were inspired by Gabriel Madeleine Camille Dareste's five principles of experimental teratology published in 1877. Teratology is the study of birth defects, and a teratogen is something that either induces or amplifies abnormal embryonic or fetal development and causes birth defects.
Format: Articles
Subject: Processes, Reproduction
Meiosis in Humans
Meiosis, the process by which sexually-reproducing organisms generate gametes (sex cells), is an essential precondition for the normal formation of the embryo. As sexually reproducing, diploid, multicellular eukaryotes, humans rely on meiosis to serve a number of important functions, including the promotion of genetic diversity and the creation of proper conditions for reproductive success.
Format: Articles
Subject: Processes, Reproduction
Zidovudine or Azidothymidine (AZT)
In 1964, Jerome Horwitz synthesized the drug zidovudine, commonly abbreviated ZDV, otherwise known as azidothymidine, or AZT, at Wayne State University School of Medicine in Detroit, Michigan. Horwitz and his colleagues originally developed zidovudine to treat cancers caused by retroviruses. In 1983, Nobel Prize in Physiology or Medicine recipients Françoise Barré-Sinoussi and Luc Montagnier discovered a new retrovirus, the human immunodeficiency virus, or HIV, at the Pasteur Institute in Paris, France.
Format: Articles
Subject: Processes
Fetal Programming
Fetal programming, or prenatal programming, is a concept that suggests certain events occurring during critical points of pregnancy may cause permanent effects on the fetus and the infant long after birth. The concept of fetal programming stemmed from the fetal origins hypothesis, also known as Barker’s hypothesis, that David Barker proposed in 1995 at the University of Southampton in Southampton, England.
Format: Articles
Subject: Processes, Theories, Reproduction
“Pelvic Organ Prolapse Quantification System (POP-Q) - A New Era in Pelvic Prolapse Staging” (2011), by Cristian Persu, Christopher Chapple, Victor Cauni, Stefan Gutue, and Petrisor Geavlete
In 2011, Cristian Persu, Christopher Chapple, Victor Cauni, Stefan Gutue, and Petrisor Geavlete published “Pelvic Organ Prolapse Quantification System (POP-Q) – A New Era in Pelvic Prolapse Staging,” in the Journal of Medicine and Life. In their article, the authors explain the need for a reliable diagnostic method for describing the state of a pelvic organ prolapse, or a condition that can result from weakness or damage to the muscles that support the pelvic organs, sometimes leading to bladder, bowel, and sexual dysfunction.
Format: Articles
Subject: Publications, Processes, Reproduction
"The Role of Urethra in Female Orgasm" (1950), by Ernst Gräfenberg
In 1950, physician and researcher Ernst Gräfenberg published “The Role of Urethra in Female Orgasm,” in the International Journal of Sexology. The article was one of the first to mention the area in the anterior, or front, vaginal wall colloquially called the G-spot. In the article, Gräfenberg acknowledges that many females experience problems related to sexual satisfaction, and he argues that researchers and physicians of the time did not know enough information about the anatomical mechanisms and localization of the female orgasm to help them.
Format: Articles
Subject: Publications, Reproduction, Processes
“Female Ejaculation: A Case Study” (1981), by Frank Addiego, Edwin G. Belzer Jr., Jill Comolli, William Moger, John D. Perry, and Beverly Whipple
In 1981, Frank Addiego and colleagues published “Female Ejaculation: A Case Study” in The Journal of Sex Research. In the article, the authors find that female ejaculation, or the expulsion of fluid from a female’s urethra during or before orgasm, is a legitimate phenomenon that can occur when one stimulates an area in the vaginal wall that the team names the Gräfenberg-spot. According to the authors, at the time of publication, many individuals believed that if a female expelled fluid during orgasm, the fluid was urine and, thus, improper bladder control caused the expulsions.
Format: Articles
Subject: Publications, Processes, Reproduction