Arachidonic acid in the reticuloendothelial network

Dynamics of reactive oxygen intermediate production in human glioma: n‐6 essential fatty acid effects

“…In this study, the overall response of mixed tumour cell populations was analysed, because it is known that ROIs diffuse rapidly across membranes and between cells during lipid peroxidation [28]. Non-linear analysis was necessary because a heterogeneous response of mixed cell populations was measured [14]. In the 30 tumours investigated in this study, the cellular heterogeneity of ROI metabolism detected using¯ow cytometry was supported by immunopathological evidence of cellular heterogeneity characteristic of human primary brain tumours.…”

“…Each data point de®ned the mean¯uorescence per cell in aliquots of approximately 10 6 cells mL À1 dispersed from the same tumour. The rate of ROI generation was determined using¯ow cytometric quanti®cation of mean 515±545 nm¯uorescence from an oxidized probe, 2 H ,7 H -dichloro¯uorescin, in duplicate samples incubated at 208C in the presence or absence of exogenous n-6 EFAs [14]. The basal, prestimulation rate of ROI formation was immediately monitored for 7 min to determine the unstimulated rate of cellular ROI formation.…”

“…In hepatic and mammary tumours, low levels of ROIs reported in tumour cells [8,9] may be partly due to lack of speci®c essential fatty acid (EFA) substrates [10,11]. De®ciencies in EFAs were recently observed in human glioma tissues [12], and preliminary evidence from our laboratory together with human glioma cell line experiments suggested that the addition of 1±50 mmol L À1 n-6 EFAs in vitro increased the rate of ROI formation [13,14], inhibited cell division [13], and stimulated apoptosis [15,16]. The addition of EFAs to rat R3230AC tumour cells was also associated with increased ROI formation, leading to cell death at EFA concentrations that did not affect normal cells [17].…”

Evidence for the transfer in culture of [14C]‐labelled fatty acids from macrophages to lymphocytes

“…LEAVER et aL [15] postulated that AA participates as a connective element in the immune network. These authors suggested that, in the reticuloendothelial system, AA can regulate PL turnover, Ca 2. flux, generation of free radicals, synthesis of other FA and eicosanoids.…”

Evidence that macrophages transfer arachidonic acid and cholesterol to tissues in vivo

“…22 Studies in vitro from our group indicate that the transfer of CHOL and PL from M to LY modulates the proliferation of acceptor cells. 5,9 In addition, M transfer FA to the islets of Langerhans and modulate insulin secretion.…”