Healing process

Heilung,/. healing, curing, cure. Heilungsvorgang, m. healing process. Heil-verfohren, n. healing process, -wasser, n. curative water, mineral water, -wert, m. therapeutic value. -wesen, n. medical affairs, -wirkung,/. curative effect, -wissen-schaft,/. medical science. 

Recently, a superior therapy has been approved for use by the federal government tissue-type plasminogen activator (tPA). This naturally occurring enzyme dissolves blood clots as part of the normal healing process. By administering relatively large quantities of it, clot breakdown time can be shortened from about a week to under an hour. 

Recently, the notion that the chronicity of inflammation may not actually drive the fibrogenic process has been widely appreciated (Tables 1, 2, and 3). Some propose that it is indeed the alteration of the mesenchymal cell phenotypes that disrupts the balance between collagen synthesis and degradation in the wound-healing process, highlighted by clinical evidence that shows unsuccessful treatment of fibrosis with anti-inflammatory or immunosuppressive drugs (18,19). One scenario is that mesenchymal cells (myofibroblasts and fibroblasts) are phenotypically altered and thus do not undergo apoptosis after resolution. 

Neutrophils are the most abundant of the leukocytes and account for about 60% of the total number of white blood cells. These cells are usually the first to arrive at a site of injury or inflammation. Their primary function is to attack and destroy invading bacteria. In fact, bacterial infection is typically associated with pronounced neutrophilia (an increase in the number of circulating neutrophils). These leukocytes are also involved in removal of tissue debris and therefore play a role in the healing process. 

Wounds can be categorized as acute (healing quickly on their own) or chronic (healing slowly, and often requiring medication). Chronic wounds, such as ulcers (Table 10.9), occur if some influence disrupts the normal healing process. Such influences can include diabetes, malnutrition, rheumatoid arthritis and ischaemia (inadequate flow of blood to any part of the body). Elderly people are particularly susceptible to developing chronic wounds, often resulting in the necessity for hospitalization. Ulceration (particularly of the limbs or extremities) associated with old age,... 

PDGF plays an important role in the wound healing process. It is released at the site of damage by activated platelets, and acts as a mitogen/chemoattractant for many of the cells responsible for initiation of tissue repair. It thus tends to act primarily in a paracrine manner. It also represents an autocrine/paracrine growth factor for a variety of malignant cells. 

The optimal timing of laser or surgical trabeculectomy is controversial, ranging from initial therapy to after failure of third- or fourth-line drug therapy. Antiproliferative agents such as fluorouradl and mitomycin C are used to modify the healing process and maintain patency. 

Knowing that nitric oxide and hyaluronic acid both play an important role in the wound healing process, Di Meo et al. chose to combine the properties of both entities and synthesized new NO-donors based on hyaluronic acid derivatives exhibiting a controlled NO-release under physiological conditions (in vitro tests). These derivatives were fully characterized by and 13C NMR spectroscopy and their NO release monitored by means of UV spectrophotometric measurements.47... 

They yield data on the recovery and healing processes. 

Figure 4.17 Schematic view of the chemical healing process in semi-crystalline linear polycondensates TR, transreactions AC, additional (post)condensation D, diffusion [87]. From Fakirov, S., J. Polym. Sci., Polym. Phys. Ed., 22,2095-2104 (1984), Copyright John Wiley Sons, Inc., 1984. Reprinted by permission of John Wiley Sons, Inc...

Inflammation is a local and early response of a tissue to a noxious stimulus, such as physical injury or infection. It results in an increase in the number of immune cells in the area of damage or infection which kill pathogens, remove damaged or dead cells and initiate the healing process. The well-known characteristics of inflammation are redness, heat, swelling and pain. Redness is due to increased blood flow to the damaged area caused by vasodilation of small arterioles, which facilitates an increase in the number of immune cells in the damaged area and facilitates provision... 

By means of In-situ observation of crystal growth under very high pressure, a defect healing process was studied with p-xylene crystals In p-, m-xylene mixture. Crystals, partially melted by decrease In pressure, were repressurized to grow and to heal their melted surfaces. It was found that the half-melted crystals rapidly grow and recover their rectangular growth shape within a few minutes. 

Figure 8 shows the healing process In a 70% p-xylene mixture. 

---