Abstract: Protein S, an anticoagulant factor in the protein C antithrombotic pathway, was found to be synthesized and released by six tumor cell lines of neural origin by western blotting and ELISA. The rate of synthesis ranged from three‐to 11‐fold higher than that of a microvascular endothelial cell line and 36–144% that of a hepatoma cell line. The secreted protein S displayed specific anticoagulant activity similar to that of purified plasma protein S, implying that it was fully γ‐carboxylated. Ten primary brain tumor tissues also expressed protein S antigen, as shown by western blot analysis. Expression of anticoagulantly active protein S by neural cells raises important questions concerning possible physiologic roles for this multidomain protein beyond its function in control of thrombosis.
Summary We have recently demonstrated that the proinflammatory cytokine, interleukin-6 (IL-6), could upregulate the production of protein S in the human hepatoma cell line, HepG-2, but not in endothelial cells. In this study, we have demonstrated that the combination of exogenous IL-6 and soluble IL-6 receptor (sIL-6R) could significantly upregulate protein S production in both primary human umbilical vein endothelial cells (HUVEC) and in the immortalized human microvascular endothelial cell line, HMEC-1. The IL-6/sIL-6R complex was also able to rapidly induce tyrosine phosphorylation of the IL-6 transducer, gpl30. Neutralizing antibodies directed against either IL-6 or gpl30 blocked protein S upregulation by the IL-6/sIL-6R complex. It was also observed that exogenous sIL-6R could also upregulate protein S by forming a complex with IL-6 constitutively produced by the endothelial cell. Two other cytokines which also utilize the gpl30 receptor, oncostatin M (OSM) and leukemia inhibitory factor (LIF), were also able to upregulate endothelial cell protein S. This study demonstrates a mechanism that allows endothelial cells to respond to IL-6 and also illustrates the potential importance of circulating soluble receptors in the regulation of the anticoagulation pathway.
Abstract A rapid method for determining the reactivity of murine monoclonal antibodies with apolipoprotein A‐I (Apo A‐I) isoforms has been developed. The method consists of a rapid (1–2 h) prescreening of fusion well culture fluids by using an automated immunofluorescent assay (IF A) to identify fusion well cultures producing monoclonal antibody against Apo A‐I and high‐density lipoprotein (HDL). Immediately following the IFA procedure, immunodetection of the reactivity pattern of selected fusion well culture fluids is determined by using transblotted isoforms of Apo A‐I previously separated by isoelectric focusing. Strips are prepared and stored at 4 °C in protein containing blocking solution before use. Preselected culture fluids could be tested within 6 h for qualitative reactivity with Apo A‐I isoforms. Using this procedure we selected several monoclonal antibody‐producing cultures for further studies on HDL metabolism based on their differing reactivities with Apo A‐I isoforms. This technique should be easily transferable to other laboratories for assessing proteins having multiple isoforms since the crucial steps of separation and blotting can be optimized and performed before actual testing for antibody reactivity.
High-frequency oscillations (HFOs) are a promising prognostic biomarker of surgical outcome in patients with epilepsy. Their rates of occurrence and morphology have been studied extensively using recordings from electrodes of various geometries. While electrode size is a potential confounding factor in HFO studies, it has largely been disregarded due to a lack of consistent evidence. Therefore, we designed an experiment to directly test the impact of electrode size on HFO measurement.
Terrorist attack, robbery, rape, and assault are a few of the many extreme stressors known to induce posttraumatic stress disorder (PTSD).PTSD is described in the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. as "persistent reexperiencing of [a] traumatic event, persistent avoidance of stimuli associated with the trauma...and persistent symptoms of increased arousal" [1].According to the National Institute of Mental Health, approximately 7.7 million adult Americans suffer from PTSD, with women about twice as likely to be affected [2,3].Studies have shown that anywhere from 3 to 58 percent of individuals who suffer an extreme traumatic stressor go on to develop PTSD [1].Research in neuroscience and neuropharmacology suggests that medicine might be able to break the connection between trauma and PTSD.The degree to which memories-including memory of trauma-are encoded and consolidated determines their strength.Extremely traumatic events are thought to stimulate a large release of epinephrine and norepinephrine (NE), neurotransmitters that cause overconsolidation of the corresponding memory [4].PTSD sufferers persistently have too much NE and too great a response to it, likely adding to their chronic symptoms [5].The effect on PTSD of several drugs that modify the noradrenergic system (the system that uses norepinephrine as its neurotransmitter) has been examined, with the most successful results from the beta-blocker propranolol.Several studies have shown that if propranolol is administered shortly before exposure to a traumatic story, subsequent recall of the event is attenuated when compared to the recollection of a control group [6][7][8].Other studies have demonstrated decreased incidences of PTSD in traumatized patients who took propranolol compared with those who received a placebo [9-10].Encouraging early results have prompted ethical concerns over the use of drugs like propranolol to modify memory.Liao and Sandberg examine the potential effects of propranolol and other hypothetical memory-modifying technologies (MMTs) through the lens of normative values.Their first concern is truthfulness.Modifying our memories may alter what we believe to be true.Consider a soldier who uses propranolol before battle.By reducing the emotional strength of his memory, the soldier "may come to remember and believe that he did not really want to kill the enemy, when in fact he lusted after the killing" [11].Indeed, modifying our memories may alter what we think of our
