Tissue specificity isolation

Figure 10. Tissue specific expression of p-subunit proteins in floral tissues. Stage 3 (fully opened) flowers were collected, dissected and cell wall proteins (5 pgm) from the indicated organs isolated and analyzed for p-subunit antigen. Note the high level of expression in stigma/style and anthers/pollen and restriction of the larger antigen to stigma/style tissues. PGl lane, 1 gg of purified fruit PGl protein.

Therapeutic modalities to treat extravasation events consist of specific antidotes to halt or decrease the severity of local tissue necrosis. It should be noted that only one-third of extravasation events will lead to local tissue necrosis, and most studies of antidotes are in animal models or isolated case reports. Antidotes either disperse or bind the chemotherapy agent and accelerate the removal of the agent from the tissues. Specific antidotes and their uses are presented in Table 96-16. 

A great number of tissue-specific promoters has been isolated and characterized, and some of these have been used in experimental cancer gene therapy (see Table 1). Obviously, tissue-specific promoters are also active in the normal tissue from which the tumor originated. Unless the loss of these normal cells is acceptable (as in the case of melanocytes), additional specificity mechanisms need to be considered to make the resulting vector useful for a systemic delivery. This can be achieved, for example, by introducing an additional level of specificity, such as a specificity for proliferating cells or a selectivity for other conditions that are characteristic of tumor cells (see later). 

S. Pang, S. Taneja, K. Dardashti, P. Cohan, R. Kaboo, M. Sokoloff, C. L. Tso, J. B. Dekernion, and A. S. Belldegrun, Prostate tissue specificity of the prostate-specific antigen promoter isolated from a patient with prostate cancer, Hum. Gene Ther. 6 1417 (1995). 

Watanabe et al. (2007) now have isolated and fully sequenced one tissue-specific pheromone binding protein (PBP) from antennae of A. selenaria cretacea, with a partial sequence of a second. Whereas the fully sequenced PBP was found in the antennae of both sexes, it was present in much larger quantities in antennae from males. In binding studies, the PBP was found to strongly bind the natural pheromone components (3Z,6Z,9Z-19 H and 6Z,9Z-cB-3,4-epo-19 H). Interestingly, the PBP also bound 3Z,9Z-m-6,7-epo-19 H and 3Z,6Z-m-9,10-epo-19 H, which have been shown to antagonize the behavioral response to the pheromone (Witjaksono et al., 1999). 

This technique represents an innovative method to isolate antibodies against novel membrane molecules and epitopes expressed in their native conformation and allows the identification of new tissue-specific targeting molecules. From this point of view, this approach opens a new perspective in phage display technology and represents the first key step toward in vivo application. 

The suprahypothalamic neurotransmitter level can be assessed by a determination of catecholamines in circumscribed brain areas, the technique requires preparation of frozen tissue and isolation of specific nuclei by the micropunch technique. The catecholamines and indolamines can be measured by a radio-enzymatic methods and by a high-pressure liquid chromatography (HPLC) with electrochemical detection. These mechanistic investigations are mostly initiated due to questions arising from the receptor interaction profile of the drug candidate, they may be required to prove that such receptor interactions truly change the functional state of neurotransmitters (functional expression). Mostly, however, the peripheral effects of such neurotransmitter mechanisms (for instance prolactin secretion) are sufficiently distinct. 

The methodology required for successful modification of plant metabolism has been perfected for some plant species and for specific enzymes. This methodology includes transformation of plant cells or tissues regeneration of a healthy plant from the transformed cells isolation of the gene encoding the enzyme of interest identification of promoter sequences for tissue-specific expression and targetting of the protein into the cellular compartment desired. 

The metal composition of native MTs depends on the natural source and/or on the previous exposure of the organism to metals. The inducible MT-1 and MT-2 isoforms isolated from adult and fetal human livers contain mainly zinc, while those isolated from adult human kidney contain mainly cadmium with some copper or zinc. It may be noted that in higher organisms MTs are the sole proteins in which cadmium accumulates naturally. Both mammalian tissue specific forms MT-3 and MT-4 contain zinc and copper. In contrast to MTs from mammalian sources, in which zinc, cadmium, and copper can be simultaneously bound, yeast (53 aa) and fungal (25 aa) MTs contain exclusively copper. Specific binding of cadmium or copper to different tissue specific MT forms in vivo has been encoimtered in the snail Helix pomatia. ... 

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