Agonist-induced isomerization of the alpha 1-adrenergic receptor: kinetic analysis using broken-cell and solubilized preparations.

The affinity of agonists but not antagonists at hepatic membrane alpha 1-adrenergic receptors is temperature dependent; a 100-fold higher affinity is observed at 4 degrees C than at 37 degrees C. The relationship between these two agonist affinity states was investigated by using a strategy that allows the kinetics of this transition to be examined under equilibrium conditions. When competition assays are performed at 37 degrees C for varying intervals and the reaction mixture is then rapidly cooled by freezing, allowed to thaw, and further equilibrated at 4 degrees C, a rapid and progressive decrease (t1/2 of 1-2 min) in agonist affinity occurs, the extent of which is directly related to the incubation time at 37 degrees C.

Circulating Fc-receptor blocking factors in IgA nephropathies.

Twenty-one patients with primary IgA nephropathy, 7 patients with Henoch-Schönlein nephritis and 4 patients with IgA nephropathy associated to alcoholic liver cirrhosis were tested for Fc-receptor phagocyte function by measuring the clearance of radiolabelled IgG-sensitized erythrocytes in vivo and the immune phagocytosis by monocytes in vitro. Meanwhile IgG-, IgA-, IgA1-, IgA2-, containing immune complexes, the complement components C3, C4, C3d and the HLA-A, B, DR phenotype were determined. The patients with major urinary abnormalities were well discriminated from those with only minimal hematuria by a defective macrophage function (p less than 0.

Monocyte and macrophage Fc-receptor function in systemic vasculitis with renal involvement.

The Fc-receptor function of macrophages and monocytes was studied in 10 healthy subjects and 10 patients (5 in phase of clinical activity) affected by systemic vasculitis with histological evidence of renal involvement. Macrophage function was detected by measuring the clearance in vivo of IgG-sensitized 51Cr-labelled autologous red blood cells (RBC). In vitro immune phagocytosis of monocytes was analysed as a kinetic phenomenon by incubating IgG-coated RBC with nearly pure suspensions of peripheral monocytes.

Interaction between the macrophage system and IgA immune complexes in IgA nephropathy.

In nine patients with IgA nephropathy, the function of the mononuclear phagocyte system was assessed by measuring in vivo clearance of anti-D coated red blood cells (RBC) and in vitro phagocytosis of sensitised RBC by monocytes. A strict correlation was found between in vivo macrophage function and in vitro monocyte phagocytosis. Statistical correlations were also found between in vivo clearance values and IgAIC and C3d values.

The influence of experimental hypo- and hyperthyroid states on acute and chronic inflammatory reactions: modified response to non-steroidal anti-inflammatory agents.

Hyperthyroid and hypothyroid states were induced in rats by administration of triiodothyronine or surgical thyroparathyroidectomy. The anti-inflammatory activity of Indomethacin, Oxametacine and Phenylbutazone was evaluated in these animals using paw oedema provoked by carrageenan granulomas induced by cotton pellets and polyarthritis induced by Freund complete adjuvant. Our results indicate that the hyperthyroid state leads to a significant inhibition of the acute inflammatory response to carrageenan, while hypothyroidism has no effect.

[Influence of thyroid states on PGE2 biosynthesis].

Hyperthyroid and hypothyroid states were induced in the rat by daily injection of 3,3',5-triiodothyronine (T3; 33 microgram/100 g b. wt., ip for 6 days) or by thyroparathyroidectomy, respectively.

[Aspecific inhibitors of rubella virus hemagglutination in normal and thyroidectomized rats].

Thyroidectomized rats show alterations in serum lipoprotein distribution with an high increase of low density lipoproteins (LDL): however inhibitors titre was the same both in control and in treated animals. Also removal of nonspecific inhibitors by precipitation with heparin-MnCl2 or D.S.