Necrotic dead tissue

A topical enzyme aids in the removal of dead soft tissues by hastening the reduction of proteins into simpler substances. This is called proteolysis or a proteolytic action. The components of certain types of wounds, namely necrotic (dead) tissues and purulent exudates (pus-containing fluid), prevent proper wound healing. Removal of this type of debris by application of a topical enzyme aids in healing. Examples of conditions that may respond to application of a topical enzyme include second- and third-degree bums, pressure ulcers, and ulcers caused by peripheral vascular disease An example of a topical enzyme is collagenase (Santyl). 

It is known that wound malodour is due to the presence of devitalised, necrotic (dead) tissue or is the result of severe colonisation/infection of... 

Methods of malodour treatment involve a combination of (a) debridement to remove the necrotic dead tissue (b) a short dose of an antibiotic treatment and (c) a speciahst odour adsorbent dressing. Currently, all the commercial odour adsorbent dressings contain a layer of highly adsorbent ACC. It is very efficient in the adsorption of the volatile odorous molecules bacteria however, there are some issues regarding the use of ACC. The characteristics of these specialist odour adsorbent dressings can differ from relatively simple constructions to complex multilayer composites. 

Acute injury on parallel-veined leaves of monocotyledonous plants typically develops at the tip of the leaf blade. Repeated exposures to lethal dosages of fluoride will extend the necrotic lesion toward the base of the blade. Sometimes the lesions extend farther down the leaf margin than nearer the midvein, and often the lesion on one margin will extend farther down than on the opposite side. Living and dead tissue is usually separated by an abrupt line of dark-colored tissue. Successive fumigations often produce a series of these dark-colored bands. 

Plate 7. Sensitive tobacco plants (Nicotina tabacum L.. strain Bel W 3) with necrotic spots on leaves caused by ambient ozone, light brown spots having been induced by ozone injury 24 to 48 hrs ago. After longer time of exposure, dead tissue will be bleached. Phytotoxic concentrations of ozone in W. Germany have been demonstrated for the first time by the use of tobacco as indicator plant (Knabe et al.. 1973). Kettwig, W. Germany. l%7. 

Thallium scanning with the aid of computer analysis segregates the images into anatomic regions and specifically localizes areas of dead or necrotic myocardial tissue. In conjunction with ECHO or SPECT, thallium scans can correlate areas of abnormal wall motion with areas of poor perfusion. Sensitivity and specificity of thallium scanning to detect IHD disease are comparable with those of ET (75% and 80%, respectively). When used in conjunction with exercise ECG, sensitivity increases to about 80%. Thallium scanning also can be used in conjunction with ET to allow detection of lower levels of ischemia than may be determined from ECG abnormalities or patient... 

Necrotic tissue within the body evokes an inflammatory response that removes the dead tissue and is followed by wound healing and repair. Necrotic debris may also undergo dystrophic calcification. 

Hie most thorough and accurate method to debride an ulcer wound is to surgically remove any necrotic tissue. Surgical instruments (scalpel, forceps, scissors, or laser) are used to cut away the dead tissue. Surgical debridement may be associated with bleeding, which can be controlled by direct pressure, electrocautery, or by cauterising the wound with silver nitrate. ... 

Direct contact of concentrated sulfuric acid with plants will result in perforation of the plant tissue and the plant may subsequently die. The most common response of plants to acidic precipitation is low growth and the formation of foliar lesions or areas of dead tissue on the upper surface of the leaves. Necrotic spotting of the epidermis of the leaves after exposure to sulfuric acid mist has been reported in previous investigations. The effects of acid precipitation on plants are shown in Table 35.5. 

Necrotic tissue in or peripheral to the wound bed can allow bacterial proliferation and retard tissue cell growth by blocking access to nutrients and oxygen. This dead tissue can be removed by allowing the moist environment to soften and debride it. Enzymatic solutions have also been used with success. On the other hand, surgical debridement of the necrotic tissue is favored by some clinicians for wounds such as diabetic ulcers because it exposes the wound surface to healthy tissue and vasculature. 

Necrotic areas may appear on an otherwise normal appearing leaf, or they may be accompanied by varying degrees of yellow discoloration (chlorosis). Chlorosis may form a transition zone between completely dead and the healthy areas, or it may cover any portion of the living tissue. Chlorosis often develops in tissues which have accumulated an excessive but nonlethal amount of a particular toxicant. Various patterns and degrees of chlorosis occur when chlorophyll is attacked by the toxic pollutants. Characteristics of the chlorotic pattern are influenced by the sensitivity of plants exposed, type of pollutant, dosage received, and environmental conditions under which the plant is grown. 

On iris, gladiolus, tulip, and similar plants susceptible to fluoride injury, a narrow, dark-colored band often separates the dead and living tissue, and a series of these bands will develop as new tissue is killed by continued accumulations of fluorides. Similar bands may develop on leaves of susceptible woody species, but the necrotic tissues may also break away in a few days, leaving an irregular leaf margin. The leaf seldom separates from the tree because of the injury unless extremely high atmospheric concentrations of HF have occurred. 

There have, for an unusual example, emerged especially deadly strains of flesheating bacteria causing the tissue-destroying disease Group A streptococcal infection (GAS), or necrotizing fasciitis. Though rare so far, there is the question of whether this is an old disease, or whether new species or strains have come about. 

The removal of dead necrotic tissue is essential in facflitating the normal wound-heahng process. Wound dressings can accelerate the debridement process by providing the appropriate moisture, pH, temperature, and other conditions that are ideal for the autolyhc debridement process. 

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