Cell lines, importation

Swamy et al. ° used human HT-29 colon cancer cells to study the effectiveness of lovastatin and celecoxib, individually or in combination on the induction of apoptosis in human HT-29 colon cancer cells. They also studied the modulatory effect of lovastatin and celecoxib on lamin B levels, caspase-3 activity and expression in relationship to apoptosis in colon cancer cell lines. Importantly, their results showed that agents with different modes of action, when utilized in combinations, will induce apoptosis synergistically by enhancing caspase-3 activities. These authors concluded that the regulation of apoptosis is enhanced by selective agents such as lovastatin and celecoxib combinations for colon cancer prevention. 

Agonist-specific desensitization of prostacyclin-stimulated adenylate cyclase activity has been demonstrated in numerous systems, including human fibroblasts, and platelets in vitro and in vivo ". We have examined the mechanism of desensitization in both human platelets and in cells of the NCB-20 cell line Important and interesting differences have emerged which provide some insights into the events that follow agonist occupation of membrane receptors. 

Arg-2, Pro-3, Arg-4, Leu-5, Ser-6, Lys-8 Gly-9, Pro-10 and Met-11 into apelin-13 reduced [125I]-(Pyr1)apelin-13 binding to apelin receptors expressed in cell lines, suggesting they are important residues for receptor interaction. Structure activity studies using fragments of apelin-17 also identified Gln-1, Pro-12 and Phe-13 not essential for apelin binding. 

In view of the fact that large volumes have been administered to man without causing serious side effects (Zonneveld and Crommelin, 1988), it may be concluded that although liposomes can damage in vitro-cultured human cell lines (Nuzzo et al., 1985 Mayhew et al., 1987b), adverse effects observed in vivo are expected to be minimal. One should realize that liposomes reduce the toxicity of the encapsulated drug. Thus, the toxicity of liposomes may be of minor importance compared to the advantages of administration of certain chemotherapeutics encapsulated in liposomes. 

Glutamine as an important source for the synthesis of purines, pyrimidines and amino sugars is essential for most cell lines, too. High concentrations of glutamine may also effect cell growth indirectly as the major end-products are lactate and ammonia [15]. Both known to be toxic metabohtes. 

Table 2 shows the critical levels for 3 different BHK cell lines for the most important parameter. 

This proves our theory that the membrane fluidity is an important parameter increasing shear stress resistance. The studies give two possibilities of improving the resistance lowering temperature or adding cholesterol. Which one is the most convenient is dependent on the cell line and the constraints of the process. 

Tissue Culture Assay. Kogure et al. (48) report a novel tissue culture assay for detecting several types of sodium channel blockers. The mouse neuroblastoma cell line ATCC CCL 131 is grown in RPMI 1640 supplemented with 13.5% fetal bovine serum and 100 pg/ml gentamycin, in an atmosphere of 5% C0 95% air at 37 C. Ninety-six well plates are seeded with 1 x 10 cells in 200 pi of medium containing 1 mM ouabain and 0.075 mM veratridine. Veratridine and ouabain cause neuroblastoma cells to round-up and die. In the presence of sodium channel blockers (e.g., TTXs or STXs), the lethal action of veratridine is obviated and cells retain normal morphology and viability. An important feature of this assay is that a positive test for sodium channel blockers results in normal cell viability. Since bacterial extracts can contain cytotoxic components, this assay offers an advantage over tests that use cell death as an endpoint. The minimum detectable level of TTX is approximately 3 nM, or approximately 1/1000 mouse unit. 

This in vitro approach thus has a great potential for studying the intestinal absorption processes of carotenoids and other pigments. It is important to note the existence of several clones isolated from the parent Caco-2 cell line that can be used for studying... 

The above three equations (Eqs. 10-12) for the different cell lines are very similar to each other, which suggests that the inhibition against DNA topo I is probably one of the most important antitumor mechanisms for these compounds (CPT, CPT-11, SN-38, TPT, and EGCG) against the three human colon carcinoma (HCT 116, VACO 241, and SW 480) cell lines. In these equations, the number of data points (four or five) is small, but the correlations are statistically significant. 

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