Constitutive expression

Newer research has shown that the assignment of physiological activity exclusively to COX-1 and pathophysiological activity exclusively to COX-2 is not strictly valid since COX-2 is expressed constitutively in organs such as spinal cord, kidney or uterus (Fig. 2). Furthermore, COX-2 is formed during various... 

This expression constitutes an improvement. There are two advantages. First, the statistical reliability of the data analysis improves, because the variance in [A] is about constant during the experiment, whereas that of the quantity on the left side of Eq. (3-27) is not. Proper least-squares analysis requires nearly constant variance of the dependent variable. Second, one cannot as readily appreciate what the quantity on the left of Eq. (3-27) represents, as one can do with [A]t. Any discrepancy can more easily be spotted and interpreted in a display of (A] itself. 

CCL19 and CCL21, are expressed constitutively in lymph nodes, interaction of CCR7 with these ligands is predicted to promote metastasis to lymph nodes in a manner analogous to CXCR4/CXCL12. 

The importance of FAK is underlined by the finding that cells expressing a constitutively active form survive in suspension even though they are homeless. Here, the protein kinase is active regardless of the failure to make contact with an extracellular matrix. Rescue from apoptosis also occurs when cells express constitutively activated oncogenic forms of Ras or Src and thus activate Plj-kinase and the MAP kinase pathway. Unlike FAK, these not only prevent apoptosis but also promote proliferative signals that result in tumor formation. 

In contrast, some cytokines (e.g. some CSFs and EPO) appear to be expressed constitutively. In yet other instances cytokines such as PDGF and TGF-P are stored in cytoplasmic granules and can be rapidly released in response to appropriate stimuli. Other cytokines (mainly ones with growth factor activity, e.g. TGF-P, FGF and IL-1) are found bound to the extracellular matrix in connective tissue, bone and skin. These are released, bringing about a biological response upon tissue injury. 

The sole biochemical function of 2 -5A (and hence 2 -5 A synthetase) appears to be as an activator of a dormant endo-RNase, which is expressed constitutively in the cell. This RNase, known as RNase L or RNase F, cleaves all types of single-stranded RNA (ssRNA). This inhibits production of both viral and cellular proteins, thus paralyzing viral replication. Presumably, cellular destruction of the invading ssRNA will be accompanied by destruction of any additional viral components. Removal of dsRNA would facilitate deactivation of the endo-RNase, allowing translation of cellular mRNA to resume. A 2-5 phosphodiesterase represents a third enzymatic... 

Simple polynomial expressions constitute the most common analytical model for partial or integral thermodynamic properties of solutions ... 

This expression constitutes the basis of current interpretations of electron transfer processes in biological systems. From Eq. (9), the functions Hg, (Q) and Hbb (Q) represent potential energy surfaces for the nuclear motion described by Xav and Xbw respectively, if the weak diagonal corrections Taa and T b are neglected. Then, the region Q Q where Xav and Xbw overlap significantly corresponds to the minimum of the intersection hypersurface between Hga (Q) and Hbb (Q)- Referring to definition (5), this implies ... 

As previously discussed, the COX-2 inhibitors have selectivity for inhibition of the COX-2 enzyme, which has low constitutive activity but is highly inducible at sites of tissue injury. In addition to the peripheral role of COX-2 in inflammation, COX-2 may play an important role in the CNS. COX-2 is expressed constitutively in some excitatory neurons in the brain and spinal cord and is induced in traumatic brain injury such as that induced by ischemia and seizures. It has been hypothesized that COX-2 may also be involved in neurodegen-erative diseases, since COX-2 inhibitors have shown some positive effects in Alzheimer s disease. Thus, the mechanism of action of COX-2 inhibitors may involve brain and spinal cord sites as well as local sites of injury. 

Additional information <76, 151 > (<76>, FrzE is clearly present during vegetative growth and at much lower levels during development [122] <151>, LeETRl is expressed constitutively in all plant tissues examined [31] <151>, mRNA is constitutively expressed in vegetative and reproductive tissues [223]) [31, 122, 223]... 

Another common example arises in the expansion of the interaction energy of two atoms as a function of the inverse interatomic distance 1/Rab- This turns out to be a Taylor series which differ from the correct energy by a real contribution with zero Taylor expansion. The difference may be attributed to so-called exchange repulsion. In this case, it is nowadays known that die Taylor series has a zero convergence radius, so that the energy expression constitutes an example of an asymptotic series (to be defined in a moment) which is non-convergent for all Rab-... 

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