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Biochemistry jobs in the US, Canada, Europe and Asia. Find postdoc fellowships, research positions, and lecturer and faculty jobs. Explore more jobs in molecular biology.

Shanghai (CN) salary negotiable ShanghaiTech University

ShanghaiTech seeks innovative solutions to address the challenges that China is facing in the field of energy, material, environment, human health,etc

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Jena, Thringen (DE) Unspecified Leibniz Institute for Natural Product Research and Infection Biology

The Leibniz Institute for Natural Product Research and Infection Biology Hans Knll Institute (HKI, http://www.leibniz-hki.de) investigates the pathob...

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Atlanta, Georgia Tenure-Track Faculty position Georgia State University

Department of Chemistry at Georgia State University anticipates hiring a tenure-track faculty member at the rank of Assistant or Associate Professo...

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Miami, Florida (US) Competitive based on experience level University of Miami

The University of Miami is seeking a Post Doctoral Associate to research cancer, epigenetics and drug discovery.

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Boston, Massachusetts (US) Salary and benefits are competitive Brigham and Women's Hospital, Harvard Medical School

Postdoctoral Position Cancer Virology- investigating the molecular basis of Kaposis sarcoma herpesvirus mediated tumorigenesis using a combination

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Boston, Massachusetts (US) Competitive salary plus excellent benefits Ozcan Laboratory- Boston Children's Hospital

Postdoctoral Positions in Harvard Medical School For Obesity and Type 2 Diabetes Research

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Denver, Colorado (US) Full Time/Regular Chemistry & Biochemistry at DU

The Department of Chemistry and Biochemistry seeks outstanding applicants for a tenure-track Assistant Professor position beginning September 1, 2017.

Moscow, Moscow Competitive Thermo Fisher Scientific

Consistently achieve or exceed the territory sales plan by applying a working knowledge of Professional, Consultative and Strategic Selling skills to

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Eugene, Oregon Competitive Thermo Fisher Scientific

Perform all phases of software development including design, implementation, testing, integration, maintenance of software for the company's cell ana

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France Inserm

The Laboratory of Immunotherapy and B cell pathologies studies the implication of B-cells in autoimmune diseases for more than 30 years. The labora...

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France Inserm

The researcher will analyse the mechanisms of wound healing in the mouse model and dissect the role of sensory nerves and pain sensitivity in this ...

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France Inserm

A postdoctoral position is available in the newly established laboratory of Dr. Christophe Lachaud, located at the Cancer Research Centre of Marsei...

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Italy Stazione Zoologica Anton Dohrn

A Ph.D. fellowship is available to carry out interdisciplinary training in Biological Sciences at the Stazione Zoologica 'Anton Dohrn' Naples Italy...

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Boston, MA, US Merck

Dist. Scientist, Clinical Research-CLI005336DescriptionMerck & Co., Inc. Kenilworth, N.J., U.S.A. known as Merck in the United States and Canada, i...

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Rahway, NJ, US Merck

Associate Director, Regional Clinical Project Manager (RCPM)-CLI005343DescriptionMerck & Co., Inc. Kenilworth, N.J., U.S.A. known as Merck in the U...

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Rahway, NJ, US Merck

Scientific AVP, Clinical Research-CLI005337DescriptionMerck & Co., Inc. Kenilworth, N.J., U.S.A. known as Merck in the United States and Canada, is...

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Gwynedd, PA, US Merck

Director, Quality Assurance (Oncology)-RES001721DescriptionMerck & Co., Inc. Kenilworth, N.J., U.S.A. known as Merck in the United States and Canad...

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Gwynedd, PA, US Merck

Director, Quality Assurance (Vaccines/Infectious Diseases)-RES001719DescriptionMerck & Co., Inc. Kenilworth, N.J., U.S.A. known as Merck in the Uni...

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Gwynedd, PA, US Merck

Director, Quality Assurance (Primary Care)-RES001717DescriptionMerck & Co., Inc. Kenilworth, N.J., U.S.A. known as Merck in the United States and C...

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San Francisco, California Commensurate to NIH guidelines + comprehensive benefits + housing allowance University of California, San Francisco (UCSF)

A postdoctoral position is available in the laboratory of Sai Nair, Ph.D. at the University of California, San Francisco. We are looking for motiva...

Kln W3 Uniklinik Kln

The University of Cologne, Faculty of Medicine, posts the position of a Professorship (W3) for Biochemistry as per the requirements outlined in 3...

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Biochemistry Jobs Jobs in Biochemistry and Biological ...

Neuroscience – Wikipedia

Neuroscience is the scientific study of the nervous system.[1] Traditionally, neuroscience is recognized as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, cognitive science, computer science, engineering, linguistics, mathematics, medicine (including neurology), genetics, and allied disciplines including philosophy, physics, and psychology. It also exerts influence on other fields, such as neuroeducation,[2]neuroethics, and neurolaw. The term neurobiology is often used interchangeably with the term neuroscience, although the former refers specifically to the biology of the nervous system, whereas the latter refers to the entire science of the nervous system, including elements of psychology as well as the purely physical sciences.

The scope of neuroscience has broadened to include different approaches used to study the molecular, cellular, developmental, structural, functional, evolutionary, computational, and medical aspects of the nervous system. The techniques used by neuroscientists have also expanded enormously, from molecular and cellular studies of individual nerve cells to imaging of sensory and motor tasks in the brain. Recent theoretical advances in neuroscience have also been aided by the study of neural networks.

As a result of the increasing number of scientists who study the nervous system, several prominent neuroscience organizations have been formed to provide a forum to all neuroscientists and educators. For example, the International Brain Research Organization was founded in 1960,[3] the International Society for Neurochemistry in 1963,[4] the European Brain and Behaviour Society in 1968,[5] and the Society for Neuroscience in 1969.[6]

The study of the nervous system dates back to ancient Egypt. Evidence of trepanation, the surgical practice of either drilling or scraping a hole into the skull with the purpose of curing headaches or mental disorders or relieving cranial pressure, being performed on patients dates back to Neolithic times and has been found in various cultures throughout the world. Manuscripts dating back to 1700BC indicated that the Egyptians had some knowledge about symptoms of brain damage.[7]

Early views on the function of the brain regarded it to be a "cranial stuffing" of sorts. In Egypt, from the late Middle Kingdom onwards, the brain was regularly removed in preparation for mummification. It was believed at the time that the heart was the seat of intelligence. According to Herodotus, the first step of mummification was to "take a crooked piece of iron, and with it draw out the brain through the nostrils, thus getting rid of a portion, while the skull is cleared of the rest by rinsing with drugs."[8]

The view that the heart was the source of consciousness was not challenged until the time of the Greek physician Hippocrates. He believed that the brain was not only involved with sensationsince most specialized organs (e.g.,eyes, ears, tongue) are located in the head near the brainbut was also the seat of intelligence. Plato also speculated that the brain was the seat of the rational part of the soul.[9]Aristotle, however, believed the heart was the center of intelligence and that the brain regulated the amount of heat from the heart.[10] This view was generally accepted until the Roman physician Galen, a follower of Hippocrates and physician to Roman gladiators, observed that his patients lost their mental faculties when they had sustained damage to their brains.

Abulcasis, Averroes, Avenzoar, and Maimonides, active in the Medieval Muslim world, described a number of medical problems related to the brain. In Renaissance Europe, Vesalius (15141564), Ren Descartes (15961650), and Thomas Willis (16211675) also made several contributions to neuroscience.

In the first half of the 19th century, Jean Pierre Flourens pioneered the experimental method of carrying out localized lesions of the brain in living animals describing their effects on motricity, sensibility and behavior. Studies of the brain became more sophisticated after the invention of the microscope and the development of a staining procedure by Camillo Golgi during the late 1890s. The procedure used a silver chromate salt to reveal the intricate structures of individual neurons. His technique was used by Santiago Ramn y Cajal and led to the formation of the neuron doctrine, the hypothesis that the functional unit of the brain is the neuron.[11] Golgi and Ramn y Cajal shared the Nobel Prize in Physiology or Medicine in 1906 for their extensive observations, descriptions, and categorizations of neurons throughout the brain. While Luigi Galvani's pioneering work in the late 1700s had set the stage for studying the electrical excitability of muscles and neurons, it was in the late 19th century that Emil du Bois-Reymond, Johannes Peter Mller, and Hermann von Helmholtz demonstrated that the electrical excitation of neurons predictably affected the electrical states of adjacent neurons,[citation needed] and Richard Caton found electrical phenomena in the cerebral hemispheres of rabbits and monkeys.

In parallel with this research, work with brain-damaged patients by Paul Broca suggested that certain regions of the brain were responsible for certain functions. At the time, Broca's findings were seen as a confirmation of Franz Joseph Gall's theory that language was localized and that certain psychological functions were localized in specific areas of the cerebral cortex.[12][13] The localization of function hypothesis was supported by observations of epileptic patients conducted by John Hughlings Jackson, who correctly inferred the organization of the motor cortex by watching the progression of seizures through the body. Carl Wernicke further developed the theory of the specialization of specific brain structures in language comprehension and production. Modern research through neuroimaging techniques, still uses the Brodmann cerebral cytoarchitectonic map (referring to study of cell structure) anatomical definitions from this era in continuing to show that distinct areas of the cortex are activated in the execution of specific tasks.[14]

During the 20th century, neuroscience began to be recognized as a distinct academic discipline in its own right, rather than as studies of the nervous system within other disciplines. Eric Kandel and collaborators have cited David Rioch, Francis O. Schmitt, and Stephen Kuffler as having played critical roles in establishing the field.[15] Rioch originated the integration of basic anatomical and physiological research with clinical psychiatry at the Walter Reed Army Institute of Research, starting in the 1950s. During the same period, Schmitt established a neuroscience research program within the Biology Department at the Massachusetts Institute of Technology, bringing together biology, chemistry, physics, and mathematics. The first freestanding neuroscience department (then called Psychobiology) was founded in 1964 at the University of California, Irvine by James L. McGaugh.[citation needed] This was followed by the Department of Neurobiology at Harvard Medical School which was founded in 1966 by Stephen Kuffler.[citation needed]

In 1952, Alan Lloyd Hodgkin and Andrew Huxley presented a mathematical model for transmission of electrical signals in neurons of the giant axon of a squid, which they called "action potentials", and how they are initiated and propagated, known as the HodgkinHuxley model. In 19612, Richard FitzHugh and J. Nagumo simplified HodgkinHuxley, in what is called the FitzHughNagumo model. In 1962, Bernard Katz modeled neurotransmission across the space between neurons known as synapses. Beginning in 1966, Eric Kandel and collaborators examined biochemical changes in neurons associated with learning and memory storage in Aplysia. In 1981 Catherine Morris and Harold Lecar combined these models in the MorrisLecar model.

The scientific study of the nervous system has increased significantly during the second half of the twentieth century, principally due to advances in molecular biology, electrophysiology, and computational neuroscience. This has allowed neuroscientists to study the nervous system in all its aspects: how it is structured, how it works, how it develops, how it malfunctions, and how it can be changed. For example, it has become possible to understand, in much detail, the complex processes occurring within a single neuron. Neurons are cells specialized for communication. They are able to communicate with neurons and other cell types through specialized junctions called synapses, at which electrical or electrochemical signals can be transmitted from one cell to another. Many neurons extrude long thin filaments of protoplasm called axons, which may extend to distant parts of the body and are capable of rapidly carrying electrical signals, influencing the activity of other neurons, muscles, or glands at their termination points. A nervous system emerges from the assemblage of neurons that are connected to each other.

In vertebrates, the nervous system can be split into two parts, the central nervous system (brain and spinal cord), and the peripheral nervous system. In many species including all vertebrates the nervous system is the most complex organ system in the body, with most of the complexity residing in the brain. The human brain alone contains around one hundred billion neurons and one hundred trillion synapses; it consists of thousands of distinguishable substructures, connected to each other in synaptic networks whose intricacies have only begun to be unraveled. The majority of the approximately 2025,000 genes belonging to the human genome are expressed specifically in the brain. Due to the plasticity of the human brain, the structure of its synapses and their resulting functions change throughout life.[16] Thus the challenge of making sense of all this complexity is formidable.

The study of the nervous system can be done at multiple levels, ranging from the molecular and cellular levels to the systems and cognitive levels. At the molecular level, the basic questions addressed in molecular neuroscience include the mechanisms by which neurons express and respond to molecular signals and how axons form complex connectivity patterns. At this level, tools from molecular biology and genetics are used to understand how neurons develop and how genetic changes affect biological functions. The morphology, molecular identity, and physiological characteristics of neurons and how they relate to different types of behavior are also of considerable interest.

The fundamental questions addressed in cellular neuroscience include the mechanisms of how neurons process signals physiologically and electrochemically. These questions include how signals are processed by neurites thin extensions from a neuronal cell body, consisting of dendrites (specialized to receive synaptic inputs from other neurons) and axons (specialized to conduct nerve impulses called action potentials) and somas (the cell bodies of the neurons containing the nucleus), and how neurotransmitters and electrical signals are used to process information in a neuron. Another major area of neuroscience is directed at investigations of the development of the nervous system. These questions include the patterning and regionalization of the nervous system, neural stem cells, differentiation of neurons and glia, neuronal migration, axonal and dendritic development, trophic interactions, and synapse formation.

Computational neurogenetic modeling is concerned with the study and development of dynamic neuronal models for modeling brain functions with respect to genes and dynamic interactions between genes.

At the systems level, the questions addressed in systems neuroscience include how neural circuits are formed and used anatomically and physiologically to produce functions such as reflexes, multisensory integration, motor coordination, circadian rhythms, emotional responses, learning, and memory. In other words, they address how these neural circuits function and the mechanisms through which behaviors are generated. For example, systems level analysis addresses questions concerning specific sensory and motor modalities: how does vision work? How do songbirds learn new songs and bats localize with ultrasound? How does the somatosensory system process tactile information? The related fields of neuroethology and neuropsychology address the question of how neural substrates underlie specific animal and human behaviors. Neuroendocrinology and psychoneuroimmunology examine interactions between the nervous system and the endocrine and immune systems, respectively. Despite many advancements, the way networks of neurons produce complex cognitions and behaviors is still poorly understood.

At the cognitive level, cognitive neuroscience addresses the questions of how psychological functions are produced by neural circuitry. The emergence of powerful new measurement techniques such as neuroimaging (e.g., fMRI, PET, SPECT), electrophysiology, and human genetic analysis combined with sophisticated experimental techniques from cognitive psychology allows neuroscientists and psychologists to address abstract questions such as how human cognition and emotion are mapped to specific neural substrates. Although many studies still hold a reductionist stance looking for the neurobiological basis of cognitive phenomena, recent research shows that there is an interesting interplay between neuroscientific findings and conceptual research, soliciting and integrating both perspectives. For example, the neuroscience research on empathy solicited an interesting interdisciplinary debate involving philosophy, psychology and psychopathology.[17] Moreover, the neuroscientific identification of multiple memory systems related to different brain areas has challenged the idea of memory as a literal reproduction of the past, supporting a view of memory as a generative, constructive and dynamic process.[18]

Neuroscience is also allied with the social and behavioral sciences as well as nascent interdisciplinary fields such as neuroeconomics, decision theory, and social neuroscience to address complex questions about interactions of the brain with its environment.

Ultimately neuroscientists would like to understand every aspect of the nervous system, including how it works, how it develops, how it malfunctions, and how it can be altered or repaired. The specific topics that form the main foci of research change over time, driven by an ever-expanding base of knowledge and the availability of increasingly sophisticated technical methods. Over the long term, improvements in technology have been the primary drivers of progress. Developments in electron microscopy, computers, electronics, functional brain imaging, and most recently genetics and genomics, have all been major drivers of progress.

Most studies in neurology have too few test subjects to be scientifically sure. Those insufficient size studies are the basis for all domain-specific diagnoses in neuropsychiatry, since the few large enough studies there are always find individuals with the brain changes thought to be associated with a mental condition but without any of the symptoms. The only diagnoses that can be validated through large enough brain studies are those on serious brain damages and neurodegenerative diseases that destroy most of the brain.[19][20]

Neurology, psychiatry, neurosurgery, psychosurgery, anesthesiology and pain medicine, neuropathology, neuroradiology, ophthalmology, otolaryngology, clinical neurophysiology, addiction medicine, and sleep medicine are some medical specialties that specifically address the diseases of the nervous system. These terms also refer to clinical disciplines involving diagnosis and treatment of these diseases. Neurology works with diseases of the central and peripheral nervous systems, such as amyotrophic lateral sclerosis (ALS) and stroke, and their medical treatment. Psychiatry focuses on affective, behavioral, cognitive, and perceptual disorders. Anesthesiology focuses on perception of pain, and pharmacologic alteration of consciousness. Neuropathology focuses upon the classification and underlying pathogenic mechanisms of central and peripheral nervous system and muscle diseases, with an emphasis on morphologic, microscopic, and chemically observable alterations. Neurosurgery and psychosurgery work primarily with surgical treatment of diseases of the central and peripheral nervous systems. The boundaries between these specialties have been blurring recently as they are all influenced by basic research in neuroscience. Brain imaging also enables objective, biological insights into mental illness, which can lead to faster diagnosis, more accurate prognosis, and help assess patient progress over time.[21]

Integrative neuroscience makes connections across these specialized areas of focus.

Modern neuroscience education and research activities can be very roughly categorized into the following major branches, based on the subject and scale of the system in examination as well as distinct experimental or curricular approaches. Individual neuroscientists, however, often work on questions that span several distinct subfields.

The largest professional neuroscience organization is the Society for Neuroscience (SFN), which is based in the United States but includes many members from other countries. Since its founding in 1969 the SFN has grown steadily: as of 2010 it recorded 40,290 members from 83 different countries.[24] Annual meetings, held each year in a different American city, draw attendance from researchers, postdoctoral fellows, graduate students, and undergraduates, as well as educational institutions, funding agencies, publishers, and hundreds of businesses that supply products used in research.

Other major organizations devoted to neuroscience include the International Brain Research Organization (IBRO), which holds its meetings in a country from a different part of the world each year, and the Federation of European Neuroscience Societies (FENS), which holds a meeting in a different European city every two years. FENS comprises a set of 32 national-level organizations, including the British Neuroscience Association, the German Neuroscience Society (Neurowissenschaftliche Gesellschaft), and the French Socit des Neurosciences. The first National Honor Society in Neuroscience, Nu Rho Psi, was founded in 2006.

In 2013, the BRAIN Initiative was announced in the US.

In addition to conducting traditional research in laboratory settings, neuroscientists have also been involved in the promotion of awareness and knowledge about the nervous system among the general public and government officials. Such promotions have been done by both individual neuroscientists and large organizations. For example, individual neuroscientists have promoted neuroscience education among young students by organizing the International Brain Bee, which is an academic competition for high school or secondary school students worldwide.[25] In the United States, large organizations such as the Society for Neuroscience have promoted neuroscience education by developing a primer called Brain Facts,[26] collaborating with public school teachers to develop Neuroscience Core Concepts for K-12 teachers and students,[27] and cosponsoring a campaign with the Dana Foundation called Brain Awareness Week to increase public awareness about the progress and benefits of brain research.[28] In Canada, the CIHR Canadian National Brain Bee is held annually at McMaster University.[29]

Finally, neuroscientists have also collaborated with other education experts to study and refine educational techniques to optimize learning among students, an emerging field called educational neuroscience.[30] Federal agencies in the United States, such as the National Institute of Health (NIH)[31] and National Science Foundation (NSF),[32] have also funded research that pertains to best practices in teaching and learning of neuroscience concepts.

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Neuroscience - Wikipedia

Department Biochemistry – UVM

Our faculty, students and fellows are providing paradigm shifting advances at the cutting edge of science and medicine. We embrace a culture of transdisciplinary partnerships that transcend traditional boundaries in undergraduate, graduate and medical teaching and in pursuit of research through collaborative team approaches that combine biochemical, molecular, cellular, in vivo genetic, epigenetic, genomic, proteomic and bioinformatic strategies.

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Department Biochemistry - UVM

Molecular biology – Wikipedia, the free encyclopedia

Molecular biology concerns the molecular basis of biological activity between biomolecules in the various systems of a cell, including the interactions between DNA, RNA and proteins and their biosynthesis, as well as the regulation of these interactions.[1][2] Writing in Nature in 1961, William Astbury described molecular biology as:

"...not so much a technique as an approach, an approach from the viewpoint of the so-called basic sciences with the leading idea of searching below the large-scale manifestations of classical biology for the corresponding molecular plan. It is concerned particularly with the forms of biological molecules and [...] is predominantly three-dimensional and structuralwhich does not mean, however, that it is merely a refinement of morphology. It must at the same time inquire into genesis and function."[3]

Researchers in molecular biology use specific techniques native to molecular biology but increasingly combine these with techniques and ideas from genetics and biochemistry. There is not a defined line between these disciplines. The figure to the right is a schematic that depicts one possible view of the relationship between the fields:

Much of the work in molecular biology is quantitative, and recently much work has been done at the interface of molecular biology and computer science in bioinformatics and computational biology. As of the early 2000s, the study of gene structure and function, molecular genetics, has been among the most prominent sub-field of molecular biology.Increasingly many other loops of biology focus on molecules, either directly studying their interactions in their own right such as in cell biology and developmental biology, or indirectly, where the techniques of molecular biology are used to infer historical attributes of populations or species, as in fields in evolutionary biology such as population genetics and phylogenetics. There is also a long tradition of studying biomolecules "from the ground up" in biophysics.[citation needed]

Since the late 1950s and early 1960s, molecular biologists have learned to characterize, isolate, and manipulate the molecular components of cells and organisms.

These components include DNA, the repository of genetic information; RNA, a close relative of DNA whose functions range from serving as a temporary working copy of DNA to actual structural and enzymatic functions as well as a functional and structural part of the translational apparatus, the ribosome; and proteins, the major structural and enzymatic type of molecule in cells.[citation needed]

One of the most basic techniques of molecular biology to study protein function is molecular cloning. In this technique, DNA coding for a protein of interest is cloned (using PCR and/or restriction enzymes) into a plasmid (known as an expression vector). A vector has 3 distinctive features: an origin of replication, a multiple cloning site (MCS), and a selective marker (usually antibiotic resistance). The origin of replication will have promoter regions upstream from the replication/transcription start site.

This plasmid can be inserted into either bacterial or animal cells. Introducing DNA into bacterial cells can be done by transformation (via uptake of naked DNA), conjugation (via cell-cell contact) or by transduction (via viral vector). Introducing DNA into eukaryotic cells, such as animal cells, by physical or chemical means is called transfection. Several different transfection techniques are available, such as calcium phosphate transfection, electroporation, microinjection and liposome transfection. DNA can also be introduced into eukaryotic cells using viruses or bacteria as carriers, the latter is sometimes called bactofection and in particular uses Agrobacterium tumefaciens. The plasmid may be integrated into the genome, resulting in a stable transfection, or may remain independent of the genome, called transient transfection.

In either case, DNA coding for a protein of interest is now inside a cell, and the protein can now be expressed. A variety of systems, such as inducible promoters and specific cell-signaling factors, are available to help express the protein of interest at high levels. Large quantities of a protein can then be extracted from the bacterial or eukaryotic cell. The protein can be tested for enzymatic activity under a variety of situations, the protein may be crystallized so its tertiary structure can be studied, or, in the pharmaceutical industry, the activity of new drugs against the protein can be studied.

Polymerase chain reaction is an extremely versatile technique for copying DNA. In brief, PCR allows a specific DNA sequence to be copied or modified in predetermined ways. The reaction is extremely powerful and under perfect conditions could amplify 1 DNA molecule to become 1.07 Billion molecules in less than 2 hours. The PCR technique can be used to introduce restriction enzyme sites to ends of DNA molecules, or to mutate (change) particular bases of DNA, the latter is a method referred to as site-directed mutagenesis. PCR can also be used to determine whether a particular DNA fragment is found in a cDNA library. PCR has many variations, like reverse transcription PCR (RT-PCR) for amplification of RNA, and, more recently, quantitative PCR which allow for quantitative measurement of DNA or RNA molecules.

Gel electrophoresis is one of the principal tools of molecular biology. The basic principle is that DNA, RNA, and proteins can all be separated by means of an electric field and size. In agarose gel electrophoresis, DNA and RNA can be separated on the basis of size by running the DNA through an electrically charged agarose gel. Proteins can be separated on the basis of size by using an SDS-PAGE gel, or on the basis of size and their electric charge by using what is known as a 2D gel electrophoresis.

The terms northern, western and eastern blotting are derived from what initially was a molecular biology joke that played on the term Southern blotting, after the technique described by Edwin Southern for the hybridisation of blotted DNA. Patricia Thomas, developer of the RNA blot which then became known as the northern blot, actually didn't use the term.[4] Further combinations of these techniques produced such terms as southwesterns (protein-DNA hybridizations), northwesterns (to detect protein-RNA interactions) and farwesterns (protein-protein interactions), all of which are presently found in the literature.

Named after its inventor, biologist Edwin Southern, the Southern blot is a method for probing for the presence of a specific DNA sequence within a DNA sample. DNA samples before or after restriction enzyme (restriction endonuclease) digestion are separated by gel electrophoresis and then transferred to a membrane by blotting via capillary action. The membrane is then exposed to a labeled DNA probe that has a complement base sequence to the sequence on the DNA of interest. Most original protocols used radioactive labels; however, non-radioactive alternatives are now available. Southern blotting is less commonly used in laboratory science due to the capacity of other techniques, such as PCR, to detect specific DNA sequences from DNA samples. These blots are still used for some applications, however, such as measuring transgene copy number in transgenic mice, or in the engineering of gene knockout embryonic stem cell lines.

The northern blot is used to study the expression patterns of a specific type of RNA molecule as relative comparison among a set of different samples of RNA. It is essentially a combination of denaturing RNA gel electrophoresis, and a blot. In this process RNA is separated based on size and is then transferred to a membrane that is then probed with a labeled complement of a sequence of interest. The results may be visualized through a variety of ways depending on the label used; however, most result in the revelation of bands representing the sizes of the RNA detected in sample. The intensity of these bands is related to the amount of the target RNA in the samples analyzed. The procedure is commonly used to study when and how much gene expression is occurring by measuring how much of that RNA is present in different samples. It is one of the most basic tools for determining at what time, and under what conditions, certain genes are expressed in living tissues.

Antibodies to most proteins can be created by injecting small amounts of the protein into an animal such as a mouse, rabbit, sheep, or donkey (polyclonal antibodies) or produced in cell culture (monoclonal antibodies). These antibodies can be used for a variety of analytical and preparative techniques.

In western blotting, proteins are first separated by size, in a thin gel sandwiched between two glass plates in a technique known as SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis). The proteins in the gel are then transferred to a polyvinylidene fluoride (PVDF), nitrocellulose, nylon, or other support membrane. This membrane can then be probed with solutions of antibodies. Antibodies that specifically bind to the protein of interest can then be visualized by a variety of techniques, including colored products, chemiluminescence, or autoradiography. Often, the antibodies are labeled with enzymes. When a chemiluminescent substrate is exposed to the enzyme it allows detection. Using western blotting techniques allows not only detection but also quantitative analysis. Analogous methods to western blotting can be used to directly stain specific proteins in live cells or tissue sections. However, these immunostaining methods, such as FISH, are used more often in cell biology research.

The Eastern blotting technique is used to detect post-translational modification of proteins.[5] Proteins blotted on to the PVDF or nitrocellulose membrane are probed for modifications using specific substrates.

A DNA microarray is a collection of spots attached to a solid support such as a microscope slide where each spot contains one or more single-stranded DNA oligonucleotide fragment. Arrays make it possible to put down large quantities of very small (100 micrometre diameter) spots on a single slide. Each spot has a DNA fragment molecule that is complementary to a single DNA sequence (similar to Southern blotting). A variation of this technique allows the gene expression of an organism at a particular stage in development to be qualified (expression profiling). In this technique the RNA in a tissue is isolated and converted to labeled cDNA. This cDNA is then hybridized to the fragments on the array and visualization of the hybridization can be done. Since multiple arrays can be made with exactly the same position of fragments they are particularly useful for comparing the gene expression of two different tissues, such as a healthy and cancerous tissue. Also, one can measure what genes are expressed and how that expression changes with time or with other factors. For instance, the common baker's yeast, Saccharomyces cerevisiae, contains about 7000 genes; with a microarray, one can measure qualitatively how each gene is expressed, and how that expression changes, for example, with a change in temperature. There are many different ways to fabricate microarrays; the most common are silicon chips, microscope slides with spots of ~ 100 micrometre diameter, custom arrays, and arrays with larger spots on porous membranes (macroarrays). There can be anywhere from 100 spots to more than 10,000 on a given array. Arrays can also be made with molecules other than DNA. For example, an antibody array can be used to determine what proteins or bacteria are present in a blood sample.

Allele-specific oligonucleotide (ASO) is a technique that allows detection of single base mutations without the need for PCR or gel electrophoresis. Short (20-25 nucleotides in length), labeled probes are exposed to the non-fragmented target DNA. Hybridization occurs with high specificity due to the short length of the probes and even a single base change will hinder hybridization. The target DNA is then washed and the labeled probes that didn't hybridize are removed. The target DNA is then analyzed for the presence of the probe via radioactivity or fluorescence. In this experiment, as in most molecular biology techniques, a control must be used to ensure successful experimentation. The Illumina Methylation Assay is an example of a method that takes advantage of the ASO technique to measure one base pair differences in sequence.[citation needed]

In molecular biology, procedures and technologies are continually being developed and older technologies abandoned. For example, before the advent of DNA gel electrophoresis (agarose or polyacrylamide), the size of DNA molecules was typically determined by rate sedimentation in sucrose gradients, a slow and labor-intensive technique requiring expensive instrumentation; prior to sucrose gradients, viscometry was used. Aside from their historical interest, it is often worth knowing about older technology, as it is occasionally useful to solve another new problem for which the newer technique is inappropriate.

While molecular biology was established in the 1930s, the term was coined by Warren Weaver in 1938. Weaver was the director of Natural Sciences for the Rockefeller Foundation at the time and believed that biology was about to undergo a period of significant change given recent advances in fields such as X-ray crystallography. He therefore channeled significant amounts of (Rockefeller Institute) money into biological fields.

Clinical research and medical therapies arising from molecular biology are partly covered under gene therapy[citation needed]. The use of molecular biology or molecular cell biology approaches in medicine is now called molecular medicine. Molecular biology also plays important role in understanding formations, actions, and regulations of various parts of cells which can be used to efficiently target new drugs, diagnosis disease, and understand the physiology of the cell.

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Molecular biology - Wikipedia, the free encyclopedia

Biochemistry Home – University of Mississippi Medical Center

Dr. Yi-Tao Yu University of Rochester Medical Center Biochemistry& Biophysics RNA-Guided RNA Modification 1 p.m. Friday, Oct. 7 Room 6A

Dr. Tobias Meyer Mrs. George A.Winzer Professor in Cell Biology Chair, Chemicaland Systems Biology Stanford University School of Medicine "Molecular Mechanisms: How Human Cells Decide to Proliferate" 3 p.m. Thursday,Oct. 13 Room 3A

Dr. Mary Teruel Assistant Professor Chemical and Systems Biology Stanford University School of Medicine "Molecular Mechanisms Controlling Mammalian Cell Differentiation" 10 a.m. Friday, Oct. 14 Room 3A

Dr. Thomaqsz Heyduk Professor Edward A. Doisy Department of Biochemistry and Molecular Biology St. Louis University "Practical Biophysics: Detecting Biomolecules Using Simple Free Energy Tricks" 1 p.m. Nov. 2 Room CW106

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Biochemistry Home - University of Mississippi Medical Center

NeuroScience, Inc.

Pioneering exceptional healthcare solutions is why NeuroScience was founded sixteen years ago. We offer comprehensive proprietary supplementary blends of amino acids, herbal ingredients, vitamins, and minerals that are categorized into Catecholamine, NeuroAdrenal, NeuroImmune, and Serotonin/GABA products. These solutions are provided exclusively to heath care providers so they may integrate these products into their practice toolbox.

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Liver – Wikipedia, the free encyclopedia

The liver is a vital organ of vertebrates and some other animals.[2] In the human, it is located in the upper right quadrant of the abdomen, below the diaphragm. The liver has a wide range of functions, including detoxification of various metabolites, protein synthesis, and the production of biochemicals necessary for digestion.[3]

The liver is a gland and plays a major role in metabolism with numerous functions in the human body, including regulation of glycogen storage, decomposition of red blood cells, plasma protein synthesis, hormone production, and detoxification.[3] It is an accessory digestive gland and produces bile, an alkaline compound which aids in digestion via the emulsification of lipids. The gallbladder, a small pouch that sits just under the liver, stores bile produced by the liver.[4] The liver's highly specialized tissue consisting of mostly hepatocytes regulates a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex molecules, many of which are necessary for normal vital functions.[5] Estimates regarding the organ's total number of functions vary, but textbooks generally cite it being around 500.[6]

Terminology related to the liver often starts in hepat- from the Greek word for liver.[7]

There is currently no way to compensate for the absence of liver function in the long term, although liver dialysis techniques can be used in the short term. Artificial livers are yet to be developed to promote long term replacement in the absence of the liver. As of now,[8]liver transplantation is the only option for complete liver failure.

The liver is a reddish brown wedge-shaped organ with four lobes of unequal size and shape. A human liver normally weighs 1.441.66kg (3.23.7lb).[9] It is both the heaviest internal organ and the largest gland in the human body. Located in the right upper quadrant of the abdominal cavity, it rests just below the diaphragm, to the right of the stomach and overlies the gallbladder.[4]

The liver is connected to two large blood vessels: the hepatic artery and the portal vein. The hepatic artery carries oxygen-rich blood from the aorta, whereas the portal vein carries blood rich in digested nutrients from the entire gastrointestinal tract and also from the spleen and pancreas.[8] These blood vessels subdivide into small capillaries known as liver sinusoids, which then lead to a lobule.

Lobules are the functional units of the liver. Each lobule is made up of millions of hepatic cells (hepatocytes) which are the basic metabolic cells. The lobules are held together by fine areolar tissue which extends into the structure of the liver, by accompanying the vessels (veins and arteries) ducts and nerves through the hepatic portal, as a fibrous capsule called Glisson's capsule.[10] The whole surface of the liver is covered in a serous coat derived from peritoneum and this has an inner fibrous coat (Glisson's capsule) to which it is firmly adhered. The fibrous coat is of areolar tissue and follows the vessels and ducts to support them.

Gross anatomy traditionally divided the liver into two portions a right and a left lobe, as viewed from the front (diaphragmatic) surface; but the underside (the visceral surface) shows it to be divided into four lobes and includes the caudate and quadrate lobes.[11]

The falciform ligament, visible on the front of the liver, divides the liver into a left and a much larger right lobe. From the visceral surface, the two additional lobes are located between the right and left lobes, one in front of the other. A line can be imagined running from the left of the vena cava and all the way forward to divide the liver and gallbladder into two halves.[12] This line is called Cantlie's line.[13]

Other anatomical landmarks exist, such as the ligamentum venosum and the round ligament of the liver (ligamentum teres), which further divide the left side of the liver in two sections. An important anatomical landmark, the porta hepatis, also known as the transverse fissure of the liver, divides this left portion into four segments, which can be numbered starting at the caudate lobe as I in an anticlockwise manner. From this visceral view, seven segments can be seen, because the eighth segment is only visible in the parietal view.[14]

On the diaphragmatic surface, apart from a large triangular bare area where it connects to the diaphragm, the liver is covered by a thin double-layered membrane, the peritoneum, that help reduces friction against other organs.[15] This surface covers the convex shape of the two lobes where it accommodates the shape of the diaphragm. The peritoneum folds back on itself to form the falciform ligament and the right and left triangular ligaments.[16]

These peritoneal ligaments are not related to the anatomic ligaments in joints, and the right and left triangular ligaments have no known functional importance, though they serve as surface landmarks.[16] The falciform ligament functions to attach the liver to the posterior portion of the anterior body wall.

The visceral surface or inferior surface, is uneven and concave. It is covered in peritoneum apart from where it attaches the gallbladder and the porta hepatis.[15]

There are several impressions on the surface of the liver which accommodate the various adjacent structures and organs. Underneath the right lobe and to the right of the gallbladder fossa, are two impressions, one behind the other and separated by a ridge. The one in front is a shallow colic impression, formed by the hepatic flexure and the one behind is a deeper renal impression accommodating part of the right kidney and part of the suprarenal gland.[17]

The suprarenal impression is a small triangular depressed area on the liver. It is located close to the right of the fossa between the bare area and the caudate lobe and immediately above the renal impression. The greater part of the suprarenal impression is devoid of peritoneum and it lodges the right suprarenal gland.[18]

Medial to the renal impression is a third and slightly marked impression, lying between it and the neck of the gall-bladder. This is caused by the descending portion of the duodenum, and is known as the duodenal impression.[18]

The inferior surface of the left lobe of the liver presents behind and to the left the gastric impression.[18] This is moulded over the upper front surface of the stomach, and to the right of this is a rounded eminence, the tuber omentale, which fits into the concavity of the lesser curvature of the stomach and lies in front of the anterior layer of the lesser omentum.

Microscopically, each liver lobe is seen to be made up of hepatic lobules. The lobules are roughly hexagonal, and consist of plates of hepatocytes radiating from a central vein.[19][pageneeded]The central vein joins to the hepatic vein to carry blood out from the liver. A distinctive component of a lobule is the portal triad, which can be found running along each of the lobule's corners. The portal triad, misleadingly named, consists of five structures: a branch of the hepatic artery, a branch of the hepatic portal vein, and a bile duct, as well as lymphatic vessels and a branch of the vagus nerve.[20] Between the hepatocyte plates are liver sinusoids, which are enlarged capillaries through which blood from the hepatic portal vein and hepatic artery enters via the portal triads, then drains to the central vein.[19][pageneeded]

Histology, the study of microscopic anatomy, shows two major types of liver cell: parenchymal cells and non-parenchymal cells. 7085% of the liver volume is occupied by parenchymal hepatocytes. Non-parenchymal cells constitute 40% of the total number of liver cells but only 6.5% of its volume.[21] The liver sinusoids are lined with two types of cell, sinusoidal endothelial cells, and phagocytic Kupffer cells.[22]Hepatic stellate cells are non-parenchymal cells found in the perisinusoidal space, between a sinusoid and a hepatocyte.[21] Additionally, intrahepatic lymphocytes are often present in the sinusoidal lumen.[21]

The central area or hilum, known as the porta hepatis is where the common bile duct, hepatic portal vein, and the hepatic artery proper enter the liver. The duct, vein, and artery divide into left and right branches, and the areas of the liver supplied by these branches constitute the functional left and right lobes.The functional lobes are separated by the imaginary plane, Cantlie's line, joining the gallbladder fossa to the inferior vena cava. The plane separates the liver into the true right and left lobes. The middle hepatic vein also demarcates the true right and left lobes. The right lobe is further divided into an anterior and posterior segment by the right hepatic vein. The left lobe is divided into the medial and lateral segments by the left hepatic vein.

The fissure for the round ligament of the liver (ligamentum teres) also separates the medial and lateral segments. The medial segment is also called the quadrate lobe. In the widely used Couinaud (or "French") system, the functional lobes are further divided into a total of eight subsegments based on a transverse plane through the bifurcation of the main portal vein.[23] The caudate lobe is a separate structure which receives blood flow from both the right- and left-sided vascular branches.[24][25] The Couinaud classification of liver anatomy divides the liver into eight functionally independent segments. Each segment has its own vascular inflow, outflow and biliary drainage. In the centre of each segment there is a branch of the portal vein, hepatic artery and bile duct. In the periphery of each segment there is vascular outflow through the hepatic veins.[26] The division of the liver into independent units means that segments can be resected without damaging the remaining segments.[27] To preserve the viability of the liver following surgery, resections follow the vessels defining the peripheries of each segment. This means that resection lines parallel the hepatic veins, leaving the portal veins, bile ducts, and hepatic arteries intact.[23]

The classification system uses the vascular supply in the liver to separate the functional units (numbered I to VIII):

The remainder of the units (II to VIII) are numbered in a clockwise fashion:[26]

Units V to VIII make up the right part of the liver:[26]

Organogenesis, the development of the organs takes place from the third to the eighth week in human embryogenesis. The origins of the liver lie in both the ventral portion of the foregut endoderm (endoderm being one of the 3 embryonic germ layers) and the constituents of the adjacent septum transversum mesenchyme. In the human embryo, the hepatic diverticulum is the tube of endoderm that extends out from the foregut into the surrounding mesenchyme. The mesenchyme of septum transversum induces this endoderm to proliferate, to branch, and to form the glandular epithelium of the liver. A portion of the hepatic diverticulum (that region closest to the digestive tube) continues to function as the drainage duct of the liver, and a branch from this duct produces the gallbladder.[28] Besides signals from the septum transversum mesenchyme, fibroblast growth factor from the developing heart also contributes to hepatic competence, along with retinoic acid emanating from the lateral plate mesoderm. The hepatic endodermal cells undergo a morphological transition from columnar to pseudostratified resulting in thickening into the early liver bud. Their expansion forms a population of the bipotential hepatoblasts.[29]Hepatic stellate cells are derived from mesenchyme.[30]

After migration of hepatoblasts into the septum transversum mesenchyme, the hepatic architecture begins to be established, with liver sinusoids and bile canaliculi appearing. The liver bud separates into the lobes. The left umbilical vein becomes the ductus venosus and the right vitelline vein becomes the portal vein. The expanding liver bud is colonized by hematopoietic cells. The bipotential hepatoblasts begin differentiating into biliary epithelial cells and hepatocytes. The biliary epithelial cells differentiate from hepatoblasts around portal veins, first producing a monolayer, and then a bilayer of cuboidal cells. In ductal plate, focal dilations emerge at points in the bilayer, become surrounded by portal mesenchyme, and undergo tubulogenesis into intrahepatic bile ducts. Hepatoblasts not adjacent to portal veins instead differentiate into hepatocytes and arrange into cords lined by sinudoidal epithelial cells and bile canaliculi. Once hepatoblasts are specified into hepatocytes and undergo further expansion, they begin acquiring the functions of a mature hepatocyte, and eventually mature hepatocytes appear as highly polarized epithelial cells with abundant glycogen accumulation. In the adult liver, hepatocytes are not equivalent, with position along the portocentrovenular axis within a liver lobule dictating expression of metabolic genes involved in drug metabolism, carbohydrate metabolism, ammonia detoxification, and bile production and secretion. WNT/-catenin has now been identified to be playing a key role in this phenomenon.[29]

In the growing fetus, a major source of blood to the liver is the umbilical vein which supplies nutrients to the growing fetus. The umbilical vein enters the abdomen at the umbilicus, and passes upward along the free margin of the falciform ligament of the liver to the inferior surface of the liver. There it joins with the left branch of the portal vein. The ductus venosus carries blood from the left portal vein to the left hepatic vein and then to the inferior vena cava, allowing placental blood to bypass the liver.

In the fetus, the liver does not perform the normal digestive processes and filtration of the infant liver because nutrients are received directly from the mother via the placenta. The fetal liver releases some blood stem cells that migrate to the fetal thymus, creating the T-cells or T-lymphocytes. After birth, the formation of blood stem cells shifts to the red bone marrow.

After two to five days, the umbilical vein and ductus venosus are completely obliterated; the former becomes the round ligament of liver and the latter becomes the ligamentum venosum. In the disorders of cirrhosis and portal hypertension, the umbilical vein can open up again.

At birth the liver comprises roughly 4% of body weight and is at average 120 g. Over the course of development, it will increase to 1.41.6kg but will only take up 2.53.5% of body weight.[31]

The various functions of the liver are carried out by the liver cells or hepatocytes. The liver is thought to be responsible for up to 500 separate functions, usually in combination with other systems and organs. Currently, there is no artificial organ or device capable of reproducing all the functions of the liver. Some functions can be carried out by liver dialysis, an experimental treatment for liver failure.

The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers approximately 75% of the liver's blood supply, and carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow. Oxygen is provided from both sources; approximately half of the liver's oxygen demand is met by the hepatic portal vein, and half is met by the hepatic arteries.[32]

Blood flows through the liver sinusoids and empties into the central vein of each lobule. The central veins coalesce into hepatic veins, which leave the liver and drain into the inferior vena cava.[20]

The biliary tract is derived from the branches of the bile ducts. The biliary tract, also known as the biliary tree, is the path by which bile is secreted by the liver then transported to the first part of the small intestine, the duodenum. The bile produced in the liver is collected in bile canaliculi, small grooves between the faces of adjacent hepatocytes. The canaliculi radiate to the edge of the liver lobule, where they merge to form bile ducts. Within the liver, these ducts are termed intrahepatic bile ducts, and once they exit the liver they are considered extrahepatic. The intrahepatic ducts eventually drain into the right and left hepatic ducts, which exit the liver at the transverse fissure, and merge to form the common hepatic duct. The cystic duct from the gallbladder joins with the common hepatic duct to form the common bile duct.[20]

Bile either drains directly into the duodenum via the common bile duct, or is temporarily stored in the gallbladder via the cystic duct. The common bile duct and the pancreatic duct enter the second part of the duodenum together at the hepatopancreatic ampulla, also known as the ampulla of Vater.

The liver plays a major role in carbohydrate, protein, amino acid, and lipid metabolism.

The liver performs several roles in carbohydrate metabolism: The liver synthesizes and stores approximately 100g of glycogen via glycogenesis, the formation of glycogen from glucose. When needed, the liver releases glucose into the blood by performing glycogenolysis, the breakdown of glycogen into glucose.[33] The liver is also responsible for gluconeogenesis, which is the synthesis of glucose from certain amino acids, lactate or glycerol. Adipose and liver cells produce glycerol by breakdown of fat, which the liver uses for gluconeogenesis.[33]

The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation. It is also responsible for a large part of amino acid synthesis. The liver plays a role in the production of clotting factors as well as red blood cell production. Some of the proteins synthesized by the liver include coagulation factors I (fibrinogen), II (prothrombin), V, VII, VIII, IX, X, XI, XIII, as well as protein C, protein S and antithrombin. In the first trimester fetus, the liver is the main site of red blood cell production. By the 32nd week of gestation, the bone marrow has almost completely taken over that task. The liver is a major site of production for thrombopoietin, a glycoprotein hormone that regulates the production of platelets by the bone marrow.[34]

The liver plays several roles in lipid metabolism: it performs cholesterol synthesis, lipogenesis, the production of triglycerides, and a bulk of the body's lipoproteins are synthesized in the liver.

The liver plays a key role in digestion, as it produces and excretes bile (a yellowish liquid) required for emulsifying fats and help the absorption of vitamin K from the diet. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder.

The liver also produces insulin-like growth factor 1 (IGF-1), a polypeptide protein hormone that plays an important role in childhood growth and continues to have anabolic effects in adults.

The liver is responsible for the breakdown of insulin and other hormones. The liver breaks down bilirubin via glucuronidation, facilitating its excretion into bile. The liver is responsible for the breakdown and excretion of many waste products. It plays a key role in breaking down or modifying toxic substances (e.g., methylation) and most medicinal products in a process called drug metabolism. This sometimes results in toxication, when the metabolite is more toxic than its precursor. Preferably, the toxins are conjugated to avail excretion in bile or urine. The liver breaks down ammonia into urea as part of the urea cycle, and the urea is excreted in the urine.[19]

The oxidative capacity of the liver decreases with aging and therefore any medications that require oxidation (for instance, benzodiazepines) are more likely to accumulate to toxic levels. However, medications with shorter half-lives, such as lorazepam and oxazepam, are preferred in most cases when benzodiazepines are required in regard to geriatric medicine.

The liver is a vital organ and supports almost every other organ in the body. Because of its strategic location and multidimensional functions, the liver is also prone to many diseases.[36] The bare area of the liver is a site that is vulnerable to the passing of infection from the abdominal cavity to the thoracic cavity.

Hepatitis is a common condition of inflammation of the liver. The most usual cause of this is viral, and the most common of these infections are hepatitis A, B, C, D, and E. Some of these infections are sexually transmitted. Inflammation can also be caused by other viruses in the Herpesviridae family such as the herpes simplex virus. Infection with hepatitis B virus or hepatitis C virus is the main cause of liver cancer.[37]

Hepatic encephalopathy is caused by an accumulation of toxins in the bloodstream that are normally removed by the liver. This condition can result in coma and can prove fatal.

Other disorders caused by excessive alcohol consumption are grouped under alcoholic liver diseases and these include alcoholic hepatitis, fatty liver, and cirrhosis. Liver damage can also be caused by drugs, particularly paracetamol and drugs used to treat cancer.

BuddChiari syndrome is a condition caused by blockage of the hepatic veins (including thrombosis) that drain the liver. It presents with the classical triad of abdominal pain, ascites and liver enlargement.[38]

Primary biliary cirrhosis is an autoimmune disease of the liver.[39][40] It is marked by slow progressive destruction of the small bile ducts of the liver, with the intralobular ducts (Canals of Hering) affected early in the disease.[41] When these ducts are damaged, bile and other toxins build up in the liver (cholestasis) and over time damages the liver tissue in combination with ongoing immune related damage. This can lead to scarring (fibrosis) and cirrhosis.

Many diseases of the liver are accompanied by jaundice caused by increased levels of bilirubin in the system. The bilirubin results from the breakup of the hemoglobin of dead red blood cells; normally, the liver removes bilirubin from the blood and excretes it through bile.

There are also many pediatric liver diseases, including biliary atresia, alpha-1 antitrypsin deficiency, alagille syndrome, progressive familial intrahepatic cholestasis, Langerhans cell histiocytosis and hepatic hemangioma a benign tumour the most common type of liver tumour, thought to be congenital. Diseases that interfere with liver function will lead to derangement of these processes. However, the liver has a great capacity to regenerate and has a large reserve capacity. In most cases, the liver only produces symptoms after extensive damage.

Hepatomegaly refers to an enlarged liver and can be due to many causes. It can be palpated in a liver span measurement.

Liver diseases may be diagnosed by liver function testsblood tests that can identify various markers. For example, acute-phase reactants are produced by the liver in response to injury or inflammation.

The classic symptoms of liver damage include the following:

The diagnosis of liver disease is made by liver function tests, groups of blood tests, that can readily show the extent of liver damage. If infection is suspected, then other serological tests will be carried out. Sometimes, an ultrasound or a CT scan is needed to produce an image of the liver.

Physical examination of the liver can only reveal its size and any tenderness, and some form of imaging will also be needed.[43]

Axial CT image showing anomalous hepatic veins coursing on the subcapsular anterior surface of the liver.[44]

Maximum intensity projection (MIP) CT image as viewed anteriorly showing the anomalous hepatic veins coursing on the anterior surface of the liver

Lateral MIP view in the same patient

A CT scan in which the liver and portal vein are shown.

Damage to the liver is sometimes determined with a biopsy, particularly when the cause of liver damage is unknown. In the 21st century they have been largely replaced by high-resolution radiographic scans. The latter do not require ultrasound guidance, lab involvement, microscopic analysis, organ damage, pain, or patient sedation; and the results are available immediately on a computer screen.[citation needed]

In a biopsy, a needle is inserted into the skin just below the rib cage and a tissue sample obtained. The tissue is sent to the laboratory, where it is analyzed under a microscope. Sometimes, a radiologist may assist the physician performing a liver biopsy by providing ultrasound guidance.[45]

The liver is the only human internal organ capable of natural regeneration of lost tissue; as little as 25% of a liver can regenerate into a whole liver.[46] This is, however, not true regeneration but rather compensatory growth in mammals.[47] The lobes that are removed do not regrow and the growth of the liver is a restoration of function, not original form. This contrasts with true regeneration where both original function and form are restored. In some other species, such as fish, the liver undergoes true regeneration by restoring both shape and size of the organ.[48] In the liver, large areas of the tissues are formed but for the formation of new cells there must be sufficient amount of material so the circulation of the blood becomes more active.[49]

This is predominantly due to the hepatocytes re-entering the cell cycle. That is, the hepatocytes go from the quiescent G0 phase to the G1 phase and undergo mitosis. This process is activated by the p75 receptors.[50] There is also some evidence of bipotential stem cells, called hepatic oval cells or ovalocytes (not to be confused with oval red blood cells of ovalocytosis), which are thought to reside in the canals of Hering. These cells can differentiate into either hepatocytes or cholangiocytes. Cholangiocytes are the epithelial lining cells of the bile ducts.[51] They are cuboidal epithelium in the small interlobular bile ducts, but become columnar and mucus secreting in larger bile ducts approaching the porta hepatis and the extrahepatic ducts.

Scientific and medical works about liver regeneration often refer to the Greek Titan Prometheus who was chained to a rock in the Caucasus where, each day, his liver was devoured by an eagle, only to grow back each night. The myth suggests the ancient Greeks may have known about the livers remarkable capacity for self-repair.[52]

Human liver transplants were first performed by Thomas Starzl in the United States and Roy Calne in Cambridge, England in 1963 and 1967, respectively.

Liver transplantation is the only option for those with irreversible liver failure. Most transplants are done for chronic liver diseases leading to cirrhosis, such as chronic hepatitis C, alcoholism, autoimmune hepatitis, and many others. Less commonly, liver transplantation is done for fulminant hepatic failure, in which liver failure occurs over days to weeks.

Liver allografts for transplant usually come from donors who have died from fatal brain injury. Living donor liver transplantation is a technique in which a portion of a living person's liver is removed and used to replace the entire liver of the recipient. This was first performed in 1989 for pediatric liver transplantation. Only 20 percent of an adult's liver (Couinaud segments 2 and 3) is needed to serve as a liver allograft for an infant or small child.

More recently, adult-to-adult liver transplantation has been done using the donor's right hepatic lobe, which amounts to 60 percent of the liver. Due to the ability of the liver to regenerate, both the donor and recipient end up with normal liver function if all goes well. This procedure is more controversial, as it entails performing a much larger operation on the donor, and indeed there have been at least two donor deaths out of the first several hundred cases. A recent publication has addressed the problem of donor mortality, and at least 14 cases have been found.[53] The risk of postoperative complications (and death) is far greater in right-sided operations than that in left-sided operations.

With the recent advances of noninvasive imaging, living liver donors usually have to undergo imaging examinations for liver anatomy to decide if the anatomy is feasible for donation. The evaluation is usually performed by multidetector row computed tomography (MDCT) and magnetic resonance imaging (MRI). MDCT is good in vascular anatomy and volumetry. MRI is used for biliary tree anatomy. Donors with very unusual vascular anatomy, which makes them unsuitable for donation, could be screened out to avoid unnecessary operations.

MDCT image. Arterial anatomy contraindicated for liver donation

MDCT image. Portal venous anatomy contraindicated for liver donation

MDCT image. 3D image created by MDCT can clearly visualize the liver, measure the liver volume, and plan the dissection plane to facilitate the liver transplantation procedure.

Phase contrast CT image. Contrast is perfusing the right liver but not the left due to a left portal vein thrombus.

In Greek mythology, Prometheus was punished by the gods for revealing fire to humans, by being chained to a rock where a vulture (or an eagle) would peck out his liver, which would regenerate overnight. (The liver is the only human internal organ that actually can regenerate itself to a significant extent.) Many ancient peoples of the Near East and Mediterranean areas practiced a type of divination called haruspicy, where they tried to obtain information by examining the livers of sheep and other animals.

In Plato, and in later physiology, the liver was thought to be the seat of the darkest emotions (specifically wrath, jealousy and greed) which drive men to action.[54] The Talmud (tractate Berakhot 61b) refers to the liver as the seat of anger, with the gallbladder counteracting this.

The Persian, Urdu, and Hindi languages ( or or jigar) refer to the liver in figurative speech to indicate courage and strong feelings, or "their best"; e.g., "This Mecca has thrown to you the pieces of its liver!".[55] The term jan e jigar, literally "the strength (power) of my liver", is a term of endearment in Urdu. In Persian slang, jigar is used as an adjective for any object which is desirable, especially women. In the Zulu language, the word for liver (isibindi) is the same as the word for courage.

The legend of Liver-Eating Johnson says that he would cut out and eat the liver of each man killed after dinner.

In the motion picture The Message, Hind bint Utbah is implied or portrayed eating the liver of Hamza ibn Abd al-Muttalib during the Battle of Uhud. Although there are narrations that suggest that Hind did "taste", rather than eat, the liver of Hamza, the authenticity of these narrations has to be questioned.

On November 26, 1987, the city of Ferrol, Spain, inaugurated what is believed to be the only monument to the liver in the world. The then - major, Jaime Quintanilla, also happened to be a doctor, and thought appropriate to promote the monument. At an approximate cost of $3.200, the monument stands in the village of Baln. A plaque reads (In Galician language, free translation): "The Liver [is the] basis of Life", and below "Through History, Mankind tried to cure all illness. By helping it on this duty, you are doing a great job. We are grateful for it".[56]

The liver of mammals, fowl, and fish are commonly eaten as food by humans. Domestic pig, ox, lamb, calf, chicken, and goose livers are widely available from butchers and supermarkets.

Liver can be baked, boiled, broiled, fried, stir-fried, or eaten raw (asbeh nayeh or sawda naye in Lebanese cuisine, liver sashimi). In many preparations, pieces of liver are combined with pieces of meat or kidneys, like in the various forms of Middle Eastern mixed grill (e.g. meurav Yerushalmi). Liver is often made into spreads. Well-known examples include liver pt, foie gras, chopped liver, and leverpastej. Liver sausages such as Braunschweiger and liverwurst are also a valued meal. Liver sausages may also be used as spreads. A traditional South African delicacy, namely skilpadjies, is made of minced lamb's liver wrapped in netvet (caul fat), and grilled over an open fire.

Animal livers are rich in iron and vitamin A, and cod liver oil is commonly used as a dietary supplement. Traditionally, some fish livers were valued as food, especially the stingray liver. It was used to prepare delicacies, such as poached skate liver on toast in England, as well as the beignets de foie de raie and foie de raie en croute in French cuisine.[57]

The liver is found in all vertebrates, and is typically the largest visceral (internal) organ. Its form varies considerably in different species, and is largely determined by the shape and arrangement of the surrounding organs. Nonetheless, in most species it is divided into right and left lobes; exceptions to this general rule include snakes, where the shape of the body necessitates a simple cigar-like form. The internal structure of the liver is broadly similar in all vertebrates.[58]

An organ sometimes referred to as a liver is found associated with the digestive tract of the primitive chordate Amphioxus. Although it performs many functions of a liver, it is not considered a true liver but a homolog of the vertebrate liver.[59][60][61] The amphioxus hepatic caecum produces the liver-specific proteins vitellogenin, antithrombin, plasminogen, alanine aminotransferase, and insulin/Insulin-like growth factor (IGF)[62]

View of the various organs and blood-vessels in proximity with liver.

Liver lifted to show gall bladder and stomach in situ.

Cross section showing the liver as the large brown mass in the left of the images, right of the individual.

Cross section of an inferior portion of the liver, showing gallbladder and various structures.

Human liver. Visceral surface of liver.

Human liver. Horizontal section to newborn

Showing ligaments and bare area

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Liver - Wikipedia, the free encyclopedia

GRE biochemistry, practice test for gre subject test in …

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Nobelprize.org

106

Nobel Prizes in Physiology or Medicine have been awarded between 1901 and 2015.

Medicine Prizes have been given to one Laureate only.

women have been awarded the Medicine Prize so far.

years was the age of the youngest Medicine Laureate ever, Frederick G. Banting, who was awarded the 1923 Medicine Prize for the discovery of insulin.

years was the age of the oldest Medicine Laureate ever, Peyton Rous, when he was awarded the Medicine Prize in 1966 for his discovery of tumour-inducing viruses.

All facts and figures about the Nobel Prize in Physiology or Medicine

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Cell Biology at the University of Virginia School of Medicine

BMP and retinoic acid regulate anterior-posterior patterning of the non-axial mesoderm across the dorsal-ventral axis.

Naylor RW, Skvarca LB, Thisse C, Thisse B, Hukriede NA, Davidson AJ. Nat Commun. 2016 Jul 13;7:12197. doi: 10.1038/ncomms12197. PMID:27406002

Shetty J, Sinville R, Shumilin IA, Minor W, Zhang J, Hawkinson JE, Georg GI, Flickinger CJ, Herr JC Jan 4;121:88-96. doi: 10.1016/j.pep.2016.01.009. PMID:26777341

Fang X, Zhang B, Thisse B, Bloom GS, Thisse C. Cytoskeleton (Hoboken). 2015 Aug;72(8):422-33. doi: 10.1002/cm.21237. Epub 2015 Sep 7

James A. Simmonsa, Ryan S. D'Souzaa, Margarida Ruasb, Antony Galioneb, James E. Casanovaa and Judith M. White Journal of Virology, Aptil 2016

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Cell Biology at the University of Virginia School of Medicine