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Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.

Allergic Reactions

JoVE 10901

We speak of an allergy when the immune system triggers a response against a benign foreign structure, like food, pollen or pet dander. These elicitors are called allergens. If the immune system of a hypersensitive individual was primed against a specific allergen, it will trigger allergic symptoms during every subsequent encounter of the allergen. Symptoms can be mild, such as hay fever, to severe, such as potentially fatal anaphylactic shock. The immune system is crucial for defending an organism against bacteria, viruses, fungi, toxins, and parasites. However, in a hypersensitive response, it can be triggered by harmless substances and cause unpleasant or potentially life-threatening overreactions, called allergies. The first step toward establishing an allergy is sensitization. For instance, an individual becomes allergic to the pollen of ragweed when, for the first time, immune cells in the respiratory passage take up the pollen and degrade the allergens into fragments. These immune cells are called antigen-presenting cells, or APCs, because they display the degraded allergen fragments on their surface. Examples of APCs are dendritic cells, macrophages and B cells. Subsequently, APCs activate encountered Type 2 helper T cells (Th2). The activated Th2 then release chemical signals (e.g., cytokines) that cause B cells to differen

 Core: Biology

Autocrine Signaling

JoVE 10973

Secreted signals can act on a variety of target cells. In some cases, the cell that secretes a signal also detects and responds to the signaling molecule it produces; this is called Autocrine Signaling.

Under normal physiological conditions, autocrine signaling is important for homeostasis. This process is well characterized in the macrophages of the immune system. Macrophages secrete a variety of signals including the cytokine Interleukin-1, IL-1. The secreting macrophages also possess membrane receptors for IL-1 that, when bound, can activate an intracellular signaling cascade. The resulting intracellular signals trigger the secretion of additional cytokines including more IL-1 from the target cell. Though IL-1 secreted by these macrophages can also bind to receptors on other cells and cell types, binding to the signaling cell is important in the regulation of signal production. Autocrine signaling is also a major mechanism of cancer cell proliferation. Cancerous cells secrete a variety of growth signals to themselves, through autocrine signaling, and to nearby tissues. For example, progesterone appears to act in an autocrine manner in breast cancer, whereby progesterone binds to progesterone receptors on the signaling cell, stimulating the action of growth-promoting genes. Autocrine signaling can also play a role in the development of skin cancer by stim

 Core: Biology

Nociception

JoVE 10873

Nociception—the ability to feel pain—is essential for an organism’s survival and overall well-being. Noxious stimuli such as piercing pain from a sharp object, heat from an open flame, or contact with corrosive chemicals are first detected by sensory receptors, called nociceptors, located on nerve endings. Nociceptors express ion channels that convert noxious stimuli into electrical signals. When these signals reach the brain via sensory neurons, they are perceived as pain. Thus, pain helps the organism avoid noxious stimuli. The immune system plays an essential role in pain pathology. Upon encountering noxious stimuli, immune cells such as mast cells and macrophages present at the site of injury release inflammatory chemicals such as cytokines, chemokines, histamines, and prostaglandins. These chemicals attract other immune cells such as monocytes and T cells to the injury site. They also stimulate nociceptors, resulting in hyperalgesia—a more intense response to a previously painful stimulus, or allodynia—a painful response to a normally innocuous stimulus such as light touch. Such pain sensitization helps protect the injured site during healing. In some cases, pain outlives its role as an acute warning system if sensitization fails to resolve over time. Chronic pain—persistent or recurrent pain lasting longer than t

 Core: Biology

Assay for Cell Death: Chromium Release Assay of Cytotoxic Ability

JoVE 10505

Source: Frances V. Sjaastad1,2, Whitney Swanson2,3, and Thomas S. Griffith1,2,3,4
1 Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455
2 Center for Immunology, University of Minnesota, Minneapolis, MN 55455
3 Department of Urology, University of Minnesota, Minneapolis, MN 55455
4 Masonic…

 Immunology

Magnetic Activated Cell Sorting (MACS): Isolation of Thymic T Lymphocytes

JoVE 10495

Source: Meunier Sylvain1,2,3, Perchet Thibaut1,2,3, Sophie Novault4, Rachel Golub1,2,3
1 Unit for Lymphopoiesis, Department of Immunology, Pasteur Institute, Paris, France
2 INSERM U1223, Paris, France
3 Université Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris, France
4 Flow Cytometry Platfrom, Cytometry and Biomarkers UtechS, …

 Immunology

MALDI-TOF Mass Spectrometry

JoVE 5691

Matrix-assisted laser desorption ionization (MALDI) is a mass spectrometry ion source ideal for the analysis of biomolecules. Instead of ionizing compounds in the gaseous state, samples are embedded in a matrix, which is struck by a laser. The matrix absorbs the majority of the energy; some of this energy is then transferred to the sample, which ionizes as a result. Sample ions can then be…

 Biochemistry

ELISPOT Assay: Detection of IFN-γ Secreting Splenocytes

JoVE 10497

Source: Tonya J. Webb1
1 Department of Microbiology and Immunology, University of Maryland School of Medicine and the Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, Maryland 21201


ELISPOT is a standardized, reproducible assay used to detect cellular immune responses. The assay utilizes an enzyme-linked…

 Immunology

ELISA Assays: Indirect, Sandwich, and Competitive

JoVE 10496

Source: Whitney Swanson1,2, Frances V. Sjaastad2,3, and Thomas S. Griffith1,2,3,4
1 Department of Urology, University of Minnesota, Minneapolis, MN 55455
2 Center for Immunology, University of Minnesota, Minneapolis, MN 55455
3 Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455
4 Masonic…

 Immunology

Blood Withdrawal II

JoVE 10247

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN


The collection of blood from mice and rats for analysis can be done through a variety of methods. Each method of collection has variations in the type of restraint required, the invasiveness of the procedure, and the necessity of a general …

 Lab Animal Research
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