Extra-cellular space

Ad. 3. Manipulation of intra-f extra-cellular ration. Le Rumear et al24 manipulated intra-/extra-cellular ratios and showed that an increase in vascular volume induced by nerve stimulation increased the fraction of the slow relaxation component, while reduced intra-cellular/interstitial volume induced by osmotic diuresis decreased the fraction of the fast relaxing component and increased the fraction of the slow relaxing component, which indicates that the fast and slow relaxing component can be ascribed to the intra- and extra-cellular space, respectively. 

DIFFUSION WITHIN CELLULAR/EXTRA-CELLULAR SPACES... 

When CRs are in extra vascular volume, they occupy extra cellular space, and are designated as CRo (outside) where they directly bind with extra cellular water. 1H2O0. Since the transverse relaxation time, T is an intensive property of F O, its CR induced change depends directly on the molar ratio of CRo to H2O0. Thus measurement of T allows the direct determination of the concentration of CR (i.e.) [CR]o in the space in which CR is distributed. Further, because most of the water is intracellular ( F Oj), the change in the tissue l- O T from the entire voxel by CR allows the determination of the kinetics of water movement across the cell membrane. The kinetics is characterized by the average lifetime of a water molecule inside a cell, x. and is inversely proportional... 

Transmembrane movement of sucrose is accomplished by transport proteins in several, but not all tissue types. The most obvious example of a specific tissue type is the phloem. The sucrose concentration in this tissue can approach 0.8 M in contrast to mM concentration in the surrounding tissues and probably sub mM concentration in the extra cellular spaces surrounding the phloem (2). Transport into the cells of the phloem is difficult to study as they are an integral part of the leaf or stem structure, and may comprise only 5 to 10% of the total leaf mass. Another example of sucrose transport is the accumulation of sucrose and other nutrients by cells of... 

The pH determination by 31P NMR spectroscopy mainly reflects intracellular pH, as the phosphorus compounds and metabolites essentially are located in the intra-cellular space.223 However, NMR spectroscopy also provides possibilities for measuring extra-cellular pH using a pH-sensitive probe that remains extra-cellular. This has for example been demonstrated by Ojugo et al.,224 who used the 31P probe 3-aminopropyl phosphonate and the 19F probe 3-[/V-(4-fluoro-2-triflourmethylphenyl)-sulphamoyl]-propionic acid to determine extra-cellular pH in tumours. 

Some proteins are similar to one another and therefore can be considered members of a protein family. A few hundred such families have been identified. Most proteins are designed to work In particular places within a cell or to be released Into the extracellular extra, outside ) space. Elaborate cellular pathways ensure that proteins are transported to their proper Intracellular intra, within) locations or secreted (Chapters 16 and 17). 

Extra cellular polymeric substances (EPS) produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids, and humic substances. EPS make up the intercellular space of microbial aggregates and form the structure and architecture of the biofilm matrix. The key functions of EPS are comprised of the mediation of the initial attachment of cells to different substrate, and protection against environmental stress and dehydration. The latter has a profound impact on an array of biomedical, biotechnical, and industrial fields including pharmaceutical and surgical applications, food engineering, bioremediation. 

MRS). TCHAD-deficient patients exhibited a trend toward more lipid deposition in the extra-myocellular space but no difference in intramyo-cellular lipid deposition of the soleus muscle compared to control subjects (Fig. 23.1c, e). The lean mass compartment of the body is metaboli-cally active tissue and the most tightly associated with total energy expenditure therefore, patients with lower lean body mass may have less meta-bolicaUy active tissue and lower energy needs than the normal population. 

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