Systems biology general considerations

Type of Service. The type of service—quality assurance, methods development, or routine testing—for each instrument or laboratory is a general consideration, as is the question of whether several types of service will be required of the system. A quality assurance laboratory associated with a chemicals production facility has far simpler needs in terms of analytical capability than a methods development laboratory or one that normally analyzes biological samples for pharmacologically active compounds at sub-ppm or even ppb concentrations. On the other hand, the data storage and reduction needs of a quality assurance laboratory are usually much more pressing than those of a methods development laboratory. 

Biological Database Considerations. Since MACCS was oriented to the needs of the research chemist, biological test data and inventory information were easier to treat externally. Many chemical/pharmaceutical companies utilised a general DBMS for data related to chemical structures. These systems served their purpose well, except when chemical structures needed to be inserted into reports or otherwise keyed directly. What was needed was a system that could key both structures and general DBMS data. This required a system that interfaced MACCS with general DBMS s directly. 

The feasibility of phospholipid phase transition phenomena in the propagation of nerve impulse as well as in information transfer in biological systems in general has been noted earlier. The phase transition of model and biomembranes exhibits considerable hysteresis.The possible role of fast and slow hysteresis phenomena in biomembranes for information storage was put forward by Trauble. " ... 

SOME GENERAL CONSIDERATIONS 1.1. Metal Ions and Biological Systems... 

In the following section we will discuss the importance of these general considerations for biological systems. 

As for other biological substances, states of dynamic equiUbrium exist for the various mineral nutrients as well as mechanisms whereby a system can adjust to varying amounts of these minerals in the diet. In forms usually found in foods, and under circumstances of normal human metaboHsm, most nutrient minerals are not toxic when ingested orally. Amounts considerably greater than the recommended dietary allowances (RDAs) can generally be eaten without concern for safety (Table 1) (3). 

In addition to the effect of biological variabihty in group response for a given exposure dose, the magnitude of the dose for any given individual also determines the severity of the toxic injury. In general, the considerations for dose—response relationship with respect to both the proportion of a population responding and the severity of the response are similar for local and systemic effects. However, if metabohc activation is a factor in toxicity, then a saturation level may be reached. 

So far, as in Equation (3.33), the hydrolyses of ATP and other high-energy phosphates have been portrayed as simple processes. The situation in a real biological system is far more complex, owing to the operation of several ionic equilibria. First, ATP, ADP, and the other species in Table 3.3 can exist in several different ionization states that must be accounted for in any quantitative analysis. Second, phosphate compounds bind a variety of divalent and monovalent cations with substantial affinity, and the various metal complexes must also be considered in such analyses. Consideration of these special cases makes the quantitative analysis far more realistic. The importance of these multiple equilibria in group transfer reactions is illustrated for the hydrolysis of ATP, but the principles and methods presented are general and can be applied to any similar hydrolysis reaction. 

In general, the performance of any polymeric drug delivery system is highly dependent on both the therapeutic result desired and the milieu in which the system must operate. Both of these considerations are set by the interaction between the delivery system and the biological system in which it must operate. Most drug delivery systems, then, are intended to achieve one of the following three goals ... 

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