Biological systems lysis

A cell subjected to a stress of any kind can potentially exhibit a wide range of responses. Severe stress may lead to cell death and, ultimately, to cell lysis imposition of less severe conditions may result in a metabolically perturbed system, which may either revert to its initial state or adapt in some way to the imposed conditions. Figure 10 shows a hypothetical scheme, presented by Prokop and Bajpai [12], for the signal-response cascade associated with hydrodynamic shear stress. The signal reception/transduction mechanisms are, as yet, poorly understood. While Fig. 10 can be applied to any biological system, Namdev and... 

Biological systems often require sterilization as a step before inoculation with the appropriate microbial culture. Sterilization can be considered a reaction process in which organisms are killed, 2g often through cell lysis, using thermal or chemical routes. Consider both batch and continuous... 

Complement A term originally used to refer to the heat-labile factor in serum that causes immune cytolysis, the lysis of antibody-coated cells, and now referring to the entire functionally related system comprising at least 20 distinct serum proteins that is the effector not only of immune cytolysis but also of other biologic functions. Complement activation occurs by two different sequences, the classic and alternative pathways. The proteins of the classic pathway are termed components of complement and are designated by the symbols... 

Once deposited, there are multiple mechanisms by which an immune complex initiates an inflammatory reaction (Fig. 2). Foremost among these is activation of the complement system. Immune complexes can activate the classical complement pathway as well as, indirectly or directly, the alternative complement pathway. The biologic activities of complement activation which are relevant to tissue inflammation include the generation of anaphylatoxins C5a and C3a (H29) and chemotactic peptide C5a (H29, T6), direct and indirect membrane lysis by the terminal complement components C56789 (T17), leukocytosis by C3e (G8), macrophage activation by Bb (G12), immune complex solubilization by C3b (C21), and immune adherence, the binding and activation of cells bearing complement receptors. 

The sequential activation of either the classical or the alternative pathway, with or without complete activation of the membrane-attack complex, produces biological effector molecules that initiate inflammation and facilitate the elimination of the antigens either by lysis (e.g., bacteria) or phagocytosis (e.g., immune complexes). A few of the specific functions of the complement system follow ... 

Complement system. A group of serum proteins with the capacity to interact with each other when activated. The chain reaction of the activated complement components results in formation of a lytic complex and several biologically active peptides of low molecular weight (anaphylatoxins). The system can be activated by antigen-antibody complexes (classical pathway) and by other components, e.g. bacteria (alternative pathway). As an effector mechanism of the humoral immune response, the activated complement system facilitates opsonization, phagocytosis, and lysis of cellular antigens. Some defects in components of complement are associated with autoimmune diseases (see complement deficiency). 

An interesting approach reported for obtaining purified male and female fractions on microdevices involves acoustic differential extraction (ADE) and exploits microacoustic transducer developments (see Chapter 44 by Laurell for details). This method involves the elution of biological material from the vaginal swab under mild lysis conditions, resulting in a mixture of sperm cells and epithelial cell lysate. The sample is then infused in the microdevice, and sperm cells trapped in a monolayer above an ultrasonic transducer while free DNA (from the lysed epithelial cells) flows through the system unretained. Flow of the epithelial cell lysate is directed to the outlet reservoir... 

Integrated Microdevices for Biological Applications, Fig. 5 (a) Schematic drawing of a fully integrated microfluidic system for cell lysis, mixmg/pumping, and DNA amplification (Reprinted with permission from Lee et al. [8])... 

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