Effect upon Energy Metabolism

Under normal circumstances the supply of energy-rich compounds to fuel a cell's requirement for homeostatic control is continuously replenished by oxidative phosphorylation in the mitochondria. During cooling, however, there is a progressive exhaustion of chemical energy reserves in a cell despite the general suppressive effect of cooling on metabolism. Studies that clearly demonstrate the rapid depletion of adenine nucleotides during cold storage of organs at 0 to 2 C are suggestive that...

Optimum Temperature for Hypothermic Storage

Cooling prolongs in vitro survival because it slows metabolism, reduces the demand for oxygen and other metabolites, and conserves chemical energy. However, it does not affect all reactions to the same extent, and the net result of cooling on integrated metabolizing systems is complex, not entirely predictable, and not completely understood. The application of mathematical relationships such as the Arrhenius and the Van't Hoff rules to help quantitate, predict, and understand the mechanisms of...

Classes Of Biomaterials

All materials used for implantation must satisfy the requirement of biocompatibility. As a first step, materials should not lead to systemic toxicity, mutagenicity, carcinogenicity, pyrogenicity, irritation, or sensitization. After these criteria are met, the material may be considered as a biomaterial for augmentation or other application. At the first level a biomaterial may be biotolerant, in which case the body will isolate the implanted object with a fibrous capsule to remove any influence...

References

Baust, J.G., in Advances in Biopreservation, Baust, J.G. and Baust, J.M., Eds., Boca Raton, Taylor & Francis, 2007. 2. Fuller, B.J., Lane, N., and Benson, E.E., Life in the Frozen State, CRC Press, Boca Raton, 2004. 3. Baust, J.M., Molecular mechanisms of cellular demise associated with cryopreservation failure, Cell Preservation Technol., 1, 17, 2002. 4. Gage, A., in Advances in Biopreservation, Baust, J.G. and Baust, J.M., Eds., Boca Raton, Taylor & Francis, 2007. 5. Baust, J.M., Van...

The Cryogenic Lesion

The type of lesion produced by freezing depends on the severity of the trauma. Minor freezing injury, as would be produced by rather brief exposure to temperatures warmer than about -10 C, causes an inflammatory response, featuring hyperemia, edema, and the infiltration of neutrophils, monocytes, etc. Deep freezing, as would be produced by tissue temperatures colder than -20 to -30 C for several minutes, produces a sharply circumscribed necrosis that closely corresponds to the volume of tissue...

Adjunctive Cryotherapy

Adjunctive therapy may consist of cytotoxic drugs, irradiation, antifreeze proteins, apoptotic promoters, or other agents. The most commonly used adjunctive therapy is a cancer chemotherapeutic agent, and the use of the drug after cryosurgery has been thought to improve survival of patients.109-111 However, a measure of caution in the use of the drug is needed. The coagulopathy or complications due to the considerable cytokine release, which follows large-volume freezing, especially of the...

The Evolution Of The Multiple Endpoint And Mechanismbased Assay Concepts

A bewildering array of viability assays that can be used to assess the efficacy of a new preservation protocol or solution formulation is now available to the preservation biologist. Some of the earliest assays of historical interest were limited to a single cell type. For instance, Gulevsky et al.1 used one of the earliest assays reported in the literature when they examined the effects of hypertonic solutions and slow freezing to a variety of temperatures on the permeability of plasma...

Effect of Hypothermia on the Generation of Free Radicals

The emerging role of oxygen derived free radicals (ODFR) in tissue injury and its participation in reperfusion injury is mentioned above. Important questions that arise in the context of cold storage of tissues and organs include whether free-radical-mediated tissue injury proceeds during cold ischemia, and what effect temperature reduction has on the processes of free radical generation and the mechanisms of tissue injury. Fuller and Green and their colleagues have considered these questions...

Control Of Cryopreservationinduced Molecular Response

With the discovery of molecular responses in cells to the preservation process, there have been numerous attempts to control these events in an effort to improve preservation outcome. These approaches vary from alteration in solution (cryoprotectant carrier media) design to addition of protective agents for targeted control of apoptosis. Of these attempts the alteration in preservation solution design has proven most beneficial. 3.8.1 Next-Generation Cryopreservation Solutions The most...

The Tissue Response To Freezing Injury

The tissue response to injury by freezing is dependent upon many factors and is determined only in part by the rate of cooling or lowest temperature produced in the tissue. These physical factors are important, but other factors, such as the type of tissue and the vascular reaction to freezing temperatures, are significant factors in determining the fate of tissue frozen in vivo. With this complexity of critical elements of injury, variations in the response of cells and tissues occur, ranging...

Apoptosis vs Necrosis in Cold Induced Cell Death

Injured or dying cells exhibit characteristic changes in cell morphology and, as described above, the culmination of the deleterious events comprising the ischemic cascade is characterized by marked structural changes in cells and eventual cell death. It is now known that there are two distinct ways in which cells may die necrosis caused by a general failure of cellular homeostatic regulation following injury induced by a variety of deleterious stimuli including hypoxia, toxins, radiation, and...

Shortterm Tissue Preservation

This section deals with the issues relating to the selection and design of solutions for hypo-thermic preservation and tissue transport. Most tissues are transported on ice for short periods of time before being processed for an application or cryopreserved for long-term storage. Reference was made at the end of Chapter 2 to the importance of interventional control of the extracellular environment of cells and tissues to optimize preservation. More specifically, the composition of the buffer...

Heart Valve Leaflet 20x

FIGURE 8.3 Light microscopy of cryosubstituted frozen (A, C, E) or vitrified (B, D, F) specimens from a variety of natural tissues Jugular vein (A, B) articular cartilage (C, D) and heart valve leaflet (E, F). Cryosubstitution is a process whereby the location and size of the domains occupied by ice in the cryopreserved tissue are revealed and appear as white spaces in the tissue section (see Brockbank, K.G.M., Lightfoot, F.G., Song, Y C., and Taylor, M.J. (2000) Interstitial ice formation in...

Machine Perfusion Preservation

The development of ex vivo perfusion as a means of sustaining organ function was extensively evaluated by the Nobel prize-winning scientist Alexis Carrel and the aviator technologist Charles A. Lindbergh in the 1940s. Their aim was to simulate normal physiologic conditions with ex vivo perfusion techniques.219 This concept was modified by Ackermann and Barnard,220 who provided the isolated organs with continuous low-flow arterial circulation, using a perfusate primed with blood and oxygenated...

The Multiple Assay Tier Concept Of Viability Assays

A survey of nearly all viability assays available to the preservation scientist reveals that they can be grouped into at least four categories. The following assay tier is not specific to preservation biology, but is presented below as a tier concept that can guide those who work with preserved cells. 6.3.1 Tier 1 Assays Cytolysis Live Dead Assays This tier of assays is historically the first to be used to assess viability and still remains a key group of techniques that should be included in...

Cryosurgical Technologies And Approaches

Cryosurgical techniques directed at tissue destruction, as is required in the treatment of tumors, requires the use of apparatus and a cryogenic agent to produce tissue temperatures colder than -40 C. Citing their normal boiling points at atmospheric pressure, liquid nitrogen (-195.8 C), argon (-185 C), and nitrous oxide (-89.5 C) are the cryogens in common use today. Liquid nitrogen cools by a change in phase, that is, liquid to gas. Argon and nitrous oxide are used in pressurized cylinders...

Transitional Cell Death

Historically, molecular-based cell death has been thought to proceed through either an apoptotic or necrotic path. Apoptosis has been viewed as more of a molecular response with necrosis considered less molecular at the intracellular signaling level. However, our view of the molecular cell death landscape has evolved substantially over the past few years to suggest that apoptosis and necrosis represent more of extremes on a continuum of molecular-based cell death. Apoptosis is now viewed as a...

Biochemical and Pharmacological Additives for Preservation Media

Anti-platelet aggregation vasoactive agents Prostacyclin, PGE1, Mg 2+ Calmodulin inhibitors Calcium Channel Blockers Protease and phospholipase inhibitors Anti-oxidants free radical scavengers Chlorpromazine (CPZ), trifluoperazine Nicardipine, nifedipine, verapamil, CPZ CPZ, verapamil, calpain antagonists (e.g.AK275) Glutathione, catalase, SOD, allopurinol, dimethylthiourea, vitamin-E (or Trolox), Tempol, magnesium ascorbyl phosphate, Lazaroids LXR-015, cycloheximide, Z-VAD-FMK, Q-VD-OPH...

Desirable Properties of a Hypothermic Preservation Solution or Blood substitute

Minimizes hypothermically-induced cell swelling 2. Prevents expansion of the interstitial space (especially important during perfusion) 4. Prevents intracellular acidosis 5. Prevents injury from free radicals 6. Provides substrates for regeneration of high energy phosphate compounds during reperfusion Based on Belzer and Southard104 solutions has emerged. These are summarized in Table 2.1 based upon the exposition of Belzer and Southard.104 2.5.2 Continuous Hypothermia Perfusion Preservation...