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Humster
A humster is a hybrid cell line made from a zona-free hamster oocyte fertilized with human sperm. It always consists of single cells, and cannot form a multi-cellular being. Humsters are usually destroyed before they divide into two cells; if isolated and left alone to divide, they would still be unviable. Humsters are routinely created mainly for two reasons: * To avoid legal issues with working with pure human embryonic stem cell lines. * To assess the viability of human sperm for in vitro fertilization Somatic cell hybrids between humans and hamsters or mice have been used for the mapping of various traits since at least the 1970s. See also * Hamster zona-free ovum test The hamster zona-free ovum test (HZFO test), or hamster egg-penetration test, or sometimes just hamster test, is an in-vitro test used to study physiological profile of spermatozoa. The primary application of the test is to diagnose male infertil ... * Human–animal hybrid * Recombinant DNA Refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in floweri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Culture
Cell culture or tissue culture is the process by which cells are grown under controlled conditions, generally outside of their natural environment. The term "tissue culture" was coined by American pathologist Montrose Thomas Burrows. This technique is also called micropropagation. After the cells of interest have been isolated from living tissue, they can subsequently be maintained under carefully controlled conditions the need to be kept at body temperature (37 °C) in an incubator. These conditions vary for each cell type, but generally consist of a suitable vessel with a substrate or rich medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals), growth factors, hormones, and gases ( CO2, O2), and regulates the physio-chemical environment ( pH buffer, osmotic pressure, temperature). Most cells require a surface or an artificial substrate to form an adherent culture as a monolayer (one single-cell thick), whereas others can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamster Zona-free Ovum Test
The hamster zona-free ovum test (HZFO test), or hamster egg-penetration test, or sometimes just hamster test, is an in-vitro test used to study physiological profile of spermatozoa. The primary application of the test is to diagnose male infertility caused by sperm unable to penetrate the ova. The test has limited value, due to expense and a high false negative rate. Procedure In this test, sperm are incubated with several hamster eggs. After seven to twenty hours, the number of sperm penetrations per egg is measured. The hamster eggs have had the zona pellucida, the outer membrane, removed—hence, ''zona-free''. Having all eggs penetrated by multiple sperm is considered to be a positive sign for fertility. Results suggest that men whose sperm fail the hamster test are a third as fertile than those whose sperm pass. Although medical professionals often present the procedure as unable to create an embryo, these claims are not technically correct. If the human sperm succ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamster
Hamsters are rodents (order Rodentia) belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera.Fox, Sue. 2006. ''Hamsters''. T.F.H. Publications Inc. They have become established as popular small pets. The best-known species of hamster is the golden or Syrian hamster (''Mesocricetus auratus''), which is the type most commonly kept as pets. Other hamster species commonly kept as pets are the three species of dwarf hamster, Campbell's dwarf hamster (''Phodopus campbelli''), the winter white dwarf hamster (''Phodopus sungorus'') and the Roborovski hamster (''Phodopus roborovskii''). Hamsters are more crepuscular than nocturnal and, in the wild, remain underground during the day to avoid being caught by predators. They feed primarily on seeds, fruits, and vegetation, and will occasionally eat burrowing insects. Physically, they are stout-bodied with distinguishing features that include elongated cheek pouches extending to their shoulders, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oocyte
An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell (PGC), which then undergoes mitosis, forming oogonia. During oogenesis, the oogonia become primary oocytes. An oocyte is a form of genetic material that can be collected for cryoconservation. Formation The formation of an oocyte is called oocytogenesis, which is a part of oogenesis. Oogenesis results in the formation of both primary oocytes during fetal period, and of secondary oocytes after it as part of ovulation. Characteristics Cytoplasm Oocytes are rich in cytoplasm, which contains yolk granules to nourish the cell early in development. Nucleus During the primary oocyte stage of oogenesis, the nucleus is called a germinal vesicle. The only normal human type of secondary oocyte h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitosis
In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintained. Therefore, mitosis is also known as equational division. In general, mitosis is preceded by S phase of interphase (during which DNA replication occurs) and is often followed by telophase and cytokinesis; which divides the cytoplasm, organelles and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components. The different stages of mitosis altogether define the mitotic (M) phase of an animal cell cycle—the division of the mother cell into two daughter cells genetically identical to each other. The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are preprophase (specific to plant cells), p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viability (fetal)
Fetal viability is the ability of a human fetus to survive outside the uterus. Medical viability is generally considered to be between 23 and 24 weeks gestational age. Viability depends upon factors such as birth weight, gestational age, and the availability of advanced medical care. In low-income countries, half of newborns born at or below 32 weeks gestational age died due to a lack of medical access; in high-income countries, the vast majority of newborns born above 24 weeks gestational age survive. As of 2022, the world record for the lowest gestational age newborn to survive is held by Curtis Zy-Keith Means, who was born on 5 July 2020 in the United States, at 21 weeks and 1 day gestational age, weighing 420 grams. Definitions ''Viability'', as the word has been used in the United States constitutional law since '' Roe v. Wade'', is the potential of the fetus to survive outside the uterus after birth, natural or induced, when supported by up-to-date medicine. Fetal viability d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryonic Stem Cell
Embryonic stem cells (ESCs) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage pre- implantation embryo. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells. Isolating the inner cell mass (embryoblast) using immunosurgery results in destruction of the blastocyst, a process which raises ethical issues, including whether or not embryos at the pre-implantation stage have the same moral considerations as embryos in the post-implantation stage of development. Researchers are currently focusing heavily on the therapeutic potential of embryonic stem cells, with clinical use being the goal for many laboratories. Potential uses include the treatment of diabetes and heart disease. The cells are being studied to be used as clinical therapies, models of genetic disorders, and cellular/DNA repair. However, adverse effects in the research and clinical processes such as tumors and un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Vitro Fertilization
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) from their ovaries and letting sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy. IVF is a type of assisted reproductive technology used for infertility treatment, gestational surrogacy, and, in combination with pre-implantation genetic testing, avoiding transmission of genetic conditions. A fertilised egg from a donor may implant into a surrogate's uterus, and the resulting child is genetically unrelated to the surrogate. Some countries have banned or otherwise regulate the availability of IVF treatment, giving rise to fertility tourism. Restricti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamster Zona-free Ovum Test
The hamster zona-free ovum test (HZFO test), or hamster egg-penetration test, or sometimes just hamster test, is an in-vitro test used to study physiological profile of spermatozoa. The primary application of the test is to diagnose male infertility caused by sperm unable to penetrate the ova. The test has limited value, due to expense and a high false negative rate. Procedure In this test, sperm are incubated with several hamster eggs. After seven to twenty hours, the number of sperm penetrations per egg is measured. The hamster eggs have had the zona pellucida, the outer membrane, removed—hence, ''zona-free''. Having all eggs penetrated by multiple sperm is considered to be a positive sign for fertility. Results suggest that men whose sperm fail the hamster test are a third as fertile than those whose sperm pass. Although medical professionals often present the procedure as unable to create an embryo, these claims are not technically correct. If the human sperm succ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human–animal Hybrid
The terms human–animal hybrid and animal–human hybrid refer to an entity that incorporates elements from both humans and non-human animals. Technically, in a human–animal hybrid, each cell has both human and non-human genetic material, whereas an individual where some cells are human and some are derived from a different organism is called a human-animal chimera. Examples of human–animal hybrids mainly include humanized mice that have been genetically modified by xenotransplantation of human genes. Humanized mice are commonly used as small animal models in biological and medical research for human therapeutics. Human-animal hybrids are the subject of legal, moral, and technological debate in the context of recent advances in genetic engineering. Human–animal hybrids exist throughout social cultures for a long time (particularly in terms of mythology), being part of storytelling across multiple continents and particularly have been incorporated into comic books, fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recombinant DNA
Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) that bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome. Recombinant DNA is the general name for a piece of DNA that has been created by combining at least two fragments from two different sources. Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure, and differ only in the nucleotide sequence within that identical overall structure. Recombinant DNA molecules are sometimes called chimeric DNA, because they can be made of material from two different species, like the mythical chimera. R-DNA technology uses palindromic sequences and leads to the production of sticky and blunt ends. The DNA sequences used in the construction of recombinant DNA molecules can originate from any species. For example, plant DNA may be joined to ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
