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Biomedical subjects

I Hafström

Publications and source records attributed to I Hafström.

31 records · Page 2Linked to original sources
PubMed1988

Effects of fasting on disease activity, neutrophil function, fatty acid composition, and leukotriene biosynthesis in patients with rheumatoid arthritis.

Fourteen patients with rheumatoid arthritis (RA) were studied before, during, and after a 1-week total fast. Disease activity decreased, as did the neutrophil release of lysozyme induced by the ionophore A23187. The ability of zymosan-activated RA patient serum to aggregate control neutrophils was reduced, together with serum concentrations of C3. The relative contents of arachidonic acid and eicosapentaenoic acid were increased in serum, platelets, and neutrophils, whereas levels of linoleic acid and linolenic acid were unchanged. Fasting also reduced the release of leukotriene B4 from neutrophils. We thus conclude that a reduced ability to generate cytotaxins, reduced release of enzyme, and reduced leukotriene formation from RA neutrophils, together with an altered fatty acid composition of membrane phospholipids, may be mechanisms for the decrease of inflammatory symptoms that results from fasting.

Adult↗
PubMed1988

Rat neutrophil function, and leukotriene generation in essential fatty acid deficiency.

Since the essential fatty acid linoleic acid is the precursor of arachidonic acid and thus of leukotrine B4 (LTB4), essential fatty acid deficiency (EFAD) may result in decreased synthesis of this stimulator of neutrophil granulocyte functions. Peritoneal and blood neutrophils from rats fed a diet with only 0.3% of energy requirements as linoleic acid and exhibiting biochemical evidence of EFAD showed substantial functional impairments compared to neutrophils from rats maintained on a diet with 3% of the energy requirement as linoleic acid. Oxidative burst activation (assessed by chemiluminescence), chemotaxis and aggregation were impaired upon stimulation with formylpeptides or the ionophore A23187. In contrast, these functions were intact on stimulation with exogenous LTB4. Chemiluminescence was slightly but not significantly enhanced in EFAD rat neutrophils compared to controls when stimulated with phorbol myristate acetate (PMA). There were no differences between EFAD and control peritoneal neutrophils in the number of f-met-leu-phe (fMLP) receptors, or in their affinity for the ligand, assessed with fML(3H)P. The fraction of responding cells also were similar, assessed with dichlorofluorescein diacetate fluorescence. Moreover, the endogeneous LTB4 production in response to A23187 or fMLP was decreased by 57.7% and 63.5%, respectively, in EFAD peritoneal neutrophils. Thus, EFAD was associated with reductions of LTB4 production and neutrophil responsiveness to A23187 and formylpeptides but not to LTB4 or PMA, which supports the hypothesis that endogeneous LTB4 may contribute to the activation of neutrophil functions involved in inflammation and host defense.

Animals↗
PubMed1988

Recombinant human leukocyte interferon modulates neutrophil function in vitro.

Recombinant human interferon-alpha 2 (rIFN-alpha A) was evaluated as a modulator of neutrophil functions. Neutrophils treated with rIFN-alpha A for 1 h in vitro showed reduced chemiluminescence (CL) and aggregation in response to phagocytosis. In contrast, when certain soluble stimuli [f-met-leu-phe (fMLP) or leukotriene B4] were used, rIFN-alpha A treatment conferred a doubling of CL. This was paralleled by a similar increase in superoxide anion production and a 56% increase of release of beta-glucuronidase and lysozyme. The NBT test showed that IFN treatment did not increase the number of responding neutrophils. However, there was a significant increase in the displaceable binding of fML[3H]P. Enzyme release, aggregation, and CL in response to other soluble stimuli, the ionophore A23187 and phorbol myristate acetate were unaffected by IFN treatment. Likewise, chemotaxis was not affected. Thus, phagocytosis-associated events and aggregation were hampered by rIFN-alpha A whereas secretory responses to receptor-dependent soluble stimuli were augmented. The mechanism for the latter is most likely dependent on the observed modulation of binding of fMLP to its receptor.

Cell Migration Inhibition↗
PubMed1986

Relation to chemotactic factor gradients to neutrophil migration and orientation under agarose.

Chemotactic substances confer a migratory pattern for neutrophil granulocytes under agarose that is characteristic for each agent. To analyse the cause of such differences, we have studied neutrophil migration and orientation with f-Met-Leu-Phe (fMLP), leukotriene B4 (LTB4), and serum as chemoattractants. When these agents were used at optimal concentrations, it was observed that cells stimulated by LTB4 did not start migration as fast and did not migrate as far as those exposed to fMLP, but they maintained a higher degree of orientation. This delay in initiation of migration and maximal degree of orientation was even more marked when serum was the chemoattractant. These migration variables were related to the generation of gradients in the agarose of fML[3H]P, arachidonic-[3H]acid (AA, of which LTB4 is a metabolite), and fluorescein. The curvilinear AA gradient was flatter and more stable than those of fML[3H]P and fluorescein, which were linear. Thus, differences in the development and shape of the gradient of chemoattractant may contribute to differences in migration kinetics.

Cell Movement↗
PubMed1984

Effects of auranofin on leukotriene production and leukotriene stimulated neutrophil function.

Arachidonic acid is metabolized in neutrophils by lipoxygenase to leukotrienes, which are suggested to play a central role in inflammation. The antirheumatic drug auranofin (4 micrograms/ml) was found not to inhibit neutrophil production of the lipoxygenase products 5-HETE-, 15-HETE and LTB4, in vitro when stimulated with the calcium ionophore A23187. Auranofin, however, modulated neutrophil aggregation, enzyme release and chemotaxis induced by LTB4. The results suggest that auranofin may exert some of its antirheumatic effects through affecting neutrophil responses to leukotrienes.

Anti-Inflammatory Agents↗
PubMed1984

Effects of human interferon preparations on neutrophil function.

We have studied effects of two partially purified human leukocyte (alpha) interferon (IFN) preparations (PIF-A and PIF-B) and a highly purified fibroblast (beta) IFN on the functional activity of normal human neutrophils (PMNs). In vitro, PIF-B conferred a significant and dose-dependent enhancement of chemiluminescence (CL) induced both by phagocytosis and a soluble stimulus, f-Met-Leu-Phe, and decreased killing of Staph. aureus. In contrast, PIF-A caused only a slight inhibition of bactericidal activity and had no effects on CL. beta-IFN had no effects on either bactericidal activity or CL. Migration under agarose was decreased with all of the IFN but phagocytosis and release of enzymes was not affected. PMNs from seven patients treated with PIF-A for multiple myeloma exhibited increased CL responses but no other PMN functions were affected. The findings that human IFN preparations affect PMN functions indicate that high-dose IFN therapy of immunocompromised patients should be carefully evaluated for the possibility of increased infectious complications.

Bacteria↗
PubMed1984

Auranofin affects early events in human polymorphonuclear neutrophil activation by receptor-mediated stimuli.

Auranofin, a new oral antirheumatic gold compound, in concentrations achieved therapeutically, inhibits neutrophil phagocytosis, chemotaxis, chemiluminescence, reduction of cytochrome c, and release of lysosomal enzymes. To further characterize the mechanism by which auranofin affects neutrophils, we studied the effects of auranofin on unstimulated properties and functions of neutrophils as well as on rapidly stimulated functions. When examined by electron microscopy, 4 micrograms/ml of auranofin significantly decreased the number of visualized centriole-associated microtubules in resting cells. Furthermore, auranofin inhibited neutrophil spreading on glass and caused a decrease in negative surface charge (electrophoretic mobility). In addition, auranofin inhibited several fmet-leu-phe-stimulated responses such as shape change, increases in centriole-associated microtubules, decreases in surface charge, and elicited membrane potential changes (di-O-C5(3) dye response). Auranofin (1 micrograms/ml) inhibited fmet-leu-phe-stimulated superoxide and hydrogen peroxide production by 80% (p less than 0.05), and also increased the affinity of receptors for fmet-leu-phe (from Ka 0.035 to Ka 0.48, p less than 0.001). Auranofin also affected neutrophil responses to phorbol myristic acetate (PMA). The total amount of PMA-stimulated superoxide production was suppressed by as little as 0.4 micrograms/ml of auranofin, but the lag time for activation was shortened by low concentrations of auranofin (0.5 to 1 microgram/ml). Four micrograms per milliliter of auranofin suppressed the decrease in surface charge induced by PMA. However, auranofin did not influence superoxide production elicited by the ionophore A23187. The results indicate that auranofin affects the earliest detected responses in neutrophil activation by certain receptor-mediated stimuli.

Anti-Inflammatory Agents↗
PubMed1983

The effect of auranofin on polymorphonuclear granulocytes.

The effects of auranofin on the function of neutrophil polymorphonuclear granulocytes (PMN) have been studied in vitro and in vivo. Preincubation of human PMN with auranofin (1-4 micrograms/ml) increased their adherence to nylon fibres and f-met-leu-phe-(fMLP) induced aggregation. PMN migration, phagocytosis, bactericidal capacity and phagocytosis-associated enzyme release were all significantly inhibited by auranofin in a dose-dependent way. Enzyme release stimulated by f-MLP, chemoluminescence and the release of superoxide anions all showed a biphasic response to preincubation with auranofin. They showed an increase at low concentrations and inhibition at high concentrations. In studies of 3H-fMLP binding auranofin did not affect receptor numbers but increased binding affinity. Auranofin at higher concentrations decreased phorbolmyristate acetate and fMLP induced changes in surface charge and membrane potential. In vivo, auranofin administered to rats, did not prevent either the neutropenia induced by zymosan-activated serum or the corresponding rise in plasma lactoferrin levels. PMNs from six rheumatoid arthritis patients treated with auranofin (6 mg/day) for 23 weeks showed changes in bactericidal activity, chemotaxis and chemiluminescence independent of the clinical response. Enzyme release, however, was reduced in PMNs from clinical responders and showed no change in non-responders.

Animals↗
PubMedDate not supplied

Effects of antirheumatic treatment on gastric secretory function and salivary flow in patients with rheumatoid arthritis.

Many patients with rheumatoid arthritis have impaired gastric acid secretion and dysfunction of the lacrimal and salivary glands, conditions which have been proposed to be due to glandular atrophy. The hypothesis that the rheumatoid inflammation by itself has a depressive effect on these secretory functions was tested on 20 patients with active rheumatoid arthritis who underwent 16 weeks of sulphasalazine therapy. The patients responded well to the treatment, with reduction of joint indices and acute phase reactants. The resting and stimulated whole salivary secretion rate increased in 9/10 and 8/10 patients, respectively. The maximal gastric acid output increased in those patients who had a moderate reduction in acid output prior to treatment. When estimated by s-pepsinogen I, the gastric secretory capacity increased in all patients but one. In a group of auranofin treated patients, s-pepsinogen I rose only in those who responded to treatment with reduced disease activity. These results support the idea that the impaired secretory functions are at least partially reversible and probably also partly inflammatory mediated.

Adult↗