Origins and Characteristics

Although much is known about the processes of cancer formation, or carcinogenesis, comparatively little is known about the processes of cancer regression. The former will be explored as an introduction to the latter, and both involve the biological and chemical functions of the body, stated in terms of normal cells vs. cancerous ones. Surgical excision and radiation treatment are excluded from the discussion, though they can be selective if, say, the solid tumor is localized and has not yet spread or metastasized — and if the operations or treatments in themselves do not cause metastasis. 

It should be emphasized that there are all kinds of biochemically active, or bioactive, compounds or substances that will destroy cancer cells — and will destroy normal ones as well, and even kill the patient. For instance, some of the lesser-known antibiotics will kill cancer cells as well as bacterial cells, but are also lethal to the patient. 

We will examine in detail enzymes and enzyme inhibitors, enzymes being the proteinaceous substances that catalyze the myriad biochemical reactions or processes that occur in the body. Almost without exception, there is one enzyme specific to each biochemical reaction. (What may be called supporting reactions, side reactions, or simultaneous reactions may also be involved and, in fact, may be a necessity.) In turn, there are other proteinaceous substances, or still other chemical substances, that will inhibit, block, modulate, or control the action of enzymes, and on rare occasion, even accelerate or promote the action. Known as enzyme inhibitors, such substances may affect more than one enzyme, or many different enzymes that is, they may have side effects, or in other words, are nonselective. These inhibitors may be generated internally, or more likely may originate from external sources. That is, they may be designated as medicines. In fact, modem medicine is more and more viewed as encompassing enzymes and enzyme inhibitors. Broadly, this may be viewed as the utilization of biologically active or biochemically active substances, that is, bioactive substances, either natural or synthetic. 

DNA/RNA/protein synthesis, not only for cancerous cells, but for all cells, hence the designator cytotoxic. 

The investigations were originally concerned with lysozymes, which are enzymes occurring in mucus secretions (for instance, the mucous membranes in the nose) and which act as antibacterial agents. Thus, a vitamin A deficiency will cause the mucus secretions to cease in the intestine, which is followed by a bacterial invasion of the intestinal tissue (Macfarlane, 1985, p. 161). There is an inference that this may be the way vitamin A works against cancer, inasmuch as the action of gut flora or bacteria can be anticancer but can also produce all sorts of carcinogens. 

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As examples of the previous section have shown, bond hybrids are sometimes misaligned with respect to the line of centers between nuclei, a condition described as bond bending. Such bending may be considered to represent the influence of factors other than Bent s rule. In this section we examine the origin and characteristics of bond bending. 

The intermediate filaments are cell-specific and do not change when the cell is transformed. Thus, by identifying the type of intermediate filament present in a tumor, the origin and characteristics of even a micrometastasis can be determined. 

Materials. Origin and characteristics of the cellulose samples used are listed in Table I. The low molecular weight cellulose sample A, was prepared from American Enka rayon by hydrolysis in 4 M HCl for 15 minutes and then washed with an eluotropic series of solvents. Sheets of samples C and D were shredded in a Wiley Mill (40 mesh) before use. Sample B, with degree of polymerization DP) of 210, was used in this study except where noted. Ammonium thiocyanate (Witco Chemical) was dissolved in condensed anhydrous ammonia (Air Products). Unless otherwise noted, all chemicals were ACS reagent grade. 

Hull RN, Cherry WR, and Weaver GW. The origin and characteristics of a pig kidney cell strain, LLC-PK. In vitro 12 670-677, 1976. 

The characterization of properties of inorganic colloids is not very complicated, nevertheless, presentation of more details about turbid particles is not common [l, 26 ]. However, Alaerts and Van Haute [26 ]draw attention to the fact that an important controUing parameter in turbid water coagulation is the origin and characteristics of particles. 

The utility of the systematic name of a compound lies in the information that it provides about the parent compound, the position of bond unsaturation, and the nature, position, and orientation of substituents. The trivial name, as the term suggests, conveys little or no information about the chemical origin and characteristics of a compound (e.g., cortisol, progesterone, and testosterone). The trivial and systematic names of some of the important steroid hormones are given in Table 51-2. 

Describe the origin and characteristics of humic and fulvic acids and discuss their role in metal transport in soils. 

Potential-dependent reflectance changes at an electrode may also be a conseqnence of an electrode reaction that changes the absorption coefficient of a snrface fdm or of the solntion adjacent to the snrface. The more general term potential-modulated reflectance spectroscopy (PMR) is nsed to describe the experimental method in this case. The apparatns is the same as that nsed for EER, bnt the origin and characteristics of the PMR response are different (see, e.g.. Walker et al, 1998). 

As the figures indicate, the most naive theoretical intuition is incomplete. Below we will take up the challenge of how to explain the origins and characteristics of these microstructures. In addition, in chap. 11, we will examine the way in which a distribution of second-phase particles can alter the mechanical properties of a material. 

Photo 39 Oil must often be analyzed in the laboratory to determine its origin and characteristics. (Environment Canada)... 

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