Increased oxygen consumption observed in phorbol 12-myristate 13-acetate stimulated human cultured promonocytic U937 cell lines treated with calcitriol and retinoic acid.

Objective: To investigate the effect of phorbol 12-myristate 13-acetate (PMA) and formyl-methionyl-leucyl-phenylalanine (FMLP) on oxygen consumption of differentiated and non-differentiated immune cell lines by retinoic acid and calcitriol treatment which might be useful in subsequent elicitation of immunological action during immunosuppressive states.

Methods: PMA and FMLP were used to artificially stimulate reactive oxygen production in cultured promonocytic U937 cell line. Paralleled samples of the cultured cells were separately prepared with calcitriol (1, 25- dihydroxyvitamin D3) and retinoic acid followed by a 72-hour incubation period.

Immunotherapy in inflammatory bowel disease.

Inflammatory bowel disease affects an increasing number of patients worldwide and is associated with significant morbidity. The dysregulation of the immune system with increased expression of proinflammatory cytokines and increased mucosal expression of vascular adhesion molecules play an important role in its pathogenesis. Strategies targeting TNF-alpha and alpha4-integrin have led to the development of novel therapies for treatment of patients with IBD.

Pharmacology of receptor operated calcium entry in human neutrophils.

In neutrophils, increases in intracellular calcium [Ca(2+)](i) provide a crucial link between inflammatory mediators and inflammatory responses. The modulation of [Ca(2+)](i) fluxes in non-excitable cells such as neutrophils has been studied for more than 25 years yet remains to be resolved. In these cells, the Ca(2+) influx can occur through at least two mechanisms, as follows: one dependent on the state of filling of the endoplasmic reticulum Ca(2+) stores, termed store operated calcium entry (SOCE), and the other less studied mechanism in neutrophils which is not dependent on the state of the Ca(2+) stores but is regulated by receptor occupation, termed receptor operated calcium entry (ROCE).

Discrimination between receptor- and store-operated Ca(2+) influx in human neutrophils.

Ca(2+) and Sr(2+) entry pathways activated by pro-inflammatory agonists FMLP, LTB(4) and PAF have been compared to thapsigargin in human neutrophils. 2-APB (10microM) increased Ca(2+) influx and to a greater extent in agonist than in thapsigargin stimulated neutrophils. This action of 2-APB was specific to Ca(2+) because 2-APB did not augment Sr(2+) entry in agonist and thapsigargin stimulated neutrophils.

Actions of calcium influx blockers in human neutrophils support a role for receptor-operated calcium entry.

The action of two potent store operated Ca2+ entry (SOCE) inhibitors, ML-9 and GdCl3 on Ca2+ fluxes induced by the pro-inflammatory agonists FMLP, PAF, LTB(4) as well as the receptor-independent stimulus thapsigargin has not been documented in human neutrophils. In this study, ML-9 enhanced both release and subsequent Ca2+ influx in response to agonists whereas it enhanced Ca2+ release by thapsigargin, but inhibited Ca2+ influx. In contrast, 1muM GdCl3 completely inhibited Ca2+ influx in response to thapsigargin, but only partially blocked Ca2+ influx after agonist stimulation.

Relationship between calcium release and NADPH oxidase inhibition in human neutrophils.

The aim of this study was to investigate the possible relationship between NADPH oxidase activity and changes in cytosolic Ca(2+) in response to different agonists. Treatment of neutrophils with leukotriene B4 (LTB(4)) demonstrated characteristic changes to cytoslic Ca(2+) yielding an EC(50) of 4nM. The pA(2) values for the specific LTB(4) receptor (BLT) antagonists, U-75302 and LY-255283 were 6.

Swell activated chloride channel function in human neutrophils.

Non-excitable cells such as neutrophil granulocytes are the archetypal inflammatory immune cell involved in critical functions of the innate immune system. The electron current generated (I(e)) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential. For continuous function of the NADPH oxidase, I(e) has to be balanced to preserve electroneutrality, if not; sufficient depolarisation would prevent electrons from leaving the cell and neutrophil function would be abrogated.

Tamoxifen does not inhibit the swell activated chloride channel in human neutrophils during the respiratory burst.

Effective functioning of neutrophils relies upon electron translocation through the NADPH oxidase (NOX). The electron current generated (I(e)) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential in activated human neutrophils. Swelling activated chloride channels have been demonstrated in part to counteract the depolarisation generated by the NADPH oxidase I(e).

Characterisation of electron currents generated by the human neutrophil NADPH oxidase.

Electron transport by the human neutrophil NADPH oxidase is an important microbicidal weapon for phagocytes. The electron current (I(e)) generated by the neutrophil NADPH oxidase is poorly characterised due to the lack of appropriate electrophysiological data. In this study, I fully characterise the neutrophil generated I(e) when the NADPH oxidase is activated by NADPH and GTPgammaS.

Chloride channels activated by swell can regulate the NADPH oxidase generated membrane depolarisation in activated human neutrophils.

Chloride channels activated by swell have important functions in many physiological processes. The phagocyte NADPH oxidase is essential for host defence and it generates superoxide by transferring electrons from the donor NADPH to the acceptor O2. This electron current, induces a depolarisation of the plasma membrane.

A large biloma causing gastric outlet obstruction after a percutaneous liver biopsy.

Biloma formation has not been reported to occur after a routine percutaneous liver biopsy. It is an uncommon yet well known complication of laparoscopic cholecystectomy. We report the development of a biloma within 1 week after a liver biopsy with a Jamshidi needle in a non-cirrhotic patient with hepatitis C.

The large-conductance Ca2+-activated K+ channel is essential for innate immunity.

Neutrophil leukocytes have a pivotal function in innate immunity. Dogma dictates that the lethal blow is delivered to microbes by reactive oxygen species (ROS) and halogens, products of the NADPH oxidase, whose impairment causes immunodeficiency. However, recent evidence indicates that the microbes might be killed by proteases, activated by the oxidase through the generation of a hypertonic, K+-rich and alkaline environment in the phagocytic vacuole.

Anandamide regulates neuropeptide release from capsaicin-sensitive primary sensory neurons by activating both the cannabinoid 1 receptor and the vanilloid receptor 1 in vitro.

The effect of anandamide, which activates both the cannabinoid 1 (CB1) receptor and the vanilloid receptor 1 (VR1), was studied on calcitonin gene-related peptide (CGRP) release from cultured primary sensory neurons, the majority of which coexpress the CB1 receptor and VR1. Concentrations of anandamide < 1 micro m produced a small but significant CB1 receptor-mediated inhibition of basal CGRP release while higher concentrations induced VR1-mediated CGRP release. The excitatory effect of anandamide was potentiated by the CB1 receptor antagonist SR141716A.

The putative role of vanilloid receptor-like protein-1 in mediating high threshold noxious heat-sensitivity in rat cultured primary sensory neurons.

High threshold noxious heat-activated currents and vanilloid receptor-like protein-1 expression were studied in rat cultured primary sensory neurons to find out the molecule(s) responsible for high threshold noxious heat-sensitivity. The average temperature threshold and amplitude of high threshold noxious heat-activated currents were 51.6 +/- 0.

Selective effects of calcium chelators on anterograde and retrograde protein transport in the cell.

Calcium plays a regulatory role in several aspects of protein trafficking in the cell. Both vesicle fusion and vesicle formation can be inhibited by the addition of calcium chelators. Because the effects of calcium chelators have been studied predominantly in cell-free systems, it is not clear exactly which transport steps in the secretory pathway are sensitive to calcium levels.