Reactive systemic amyloidosis, also called AA-amyloidosis is a rare fatal complication of common chronic inflammatory diseases such as rheumatoid arthritis. It has been proposed that as yet undefined factors other than persistent elevation of serum level of the precursor protein, serum amyloid A (SAA), are also important for the development of AA-amyloidosis. In this work we show genomic evidence for a novel allelic variant of human SAA, SAA1 gamma, which we have recently identified at the protein level. The SAA1 gamma [Ala52(GCC), Ala57(GCG)] differed from SAA1 alpha [Val52(GTC), Ala57(GCG)] only at one base, indicating a single point mutation. On the other hand, SAA1 beta [Ala52(GCC), Val57(GTG)] had not only one, but additional differences in a nearby intron and this portion was identical to the SAA2 gene, suggesting a crossing-over between the SAA1 and SAA2 genes. Furthermore, we report that there was a significant difference in the observed numbers of SAA1 alleles between rheumatoid arthritis patients with AA-amyloidosis and the control population (chi 2(2) = 11.59, p = 0.003) with a higher frequency of gamma-allele in the AA-amyloid group (0.70 vs. 0.37). There was also a notable difference in the distribution of SAA1 genotypes (chi 5(2) = 14.63, p = 0.012) with an increased frequency of gamma/gamma-homozygotes in the AA-amyloid group (0.60 vs. 0.18). Thus our findings indicate that this novel allelic variant may be an important risk factor for the development of AA-amyloidosis.

The purpose of this study was to investigate the effects of 6 months of walking training on muscle strength, muscle thickness and tendon stiffness on various parts of the lower limbs in the elderly. Subjects were assigned to training (n=35) and control (n=10) groups. Maximal isometric torque (MVC) and muscle thickness for knee extensors (KE), knee flexors (KF), dorsi flexors (DF) and plantar flexors (PF) were measured. Tendon stiffness for KE and PF was measured using ultrasonography while subjects performed isometric contraction. No significant changes occurred in any measured variables in the control group. In the training group, muscle thickness increased significantly for KF and DF, but not for PF. For KE, significant increases of muscle thickness at the proximal and medial sides were observed, although mean relative increase of the eight measured sites for KE was not significant. MVC increased significantly for KF, DF, and PF, but not for KE. In addition, tendon stiffness for KE and PF did not change after training. These results indicated that walking training brought about increments of muscle thickness and strength in most of the lower limbs in the elderly, but it did not result in any changes in tendon stiffness.

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Both Kupffer cells and sinusoidal endothelial cells are engaged in the hepatic uptake of soluble IgG immune complex (IgG-IC) through Fc-receptors on their surface. Hepatocytes have also been reported to take up IgG-IC. It remains unclear, however, whether the endothelial cell degrades IgG-IC and whether the hepatocyte participates in IgG-IC clearance. In this study, normal mice received a single intravenous injection of soluble immune complex preformed in antigen excess, i.e. bovine serum albumin (BSA) anti-BSA-mouse-IgG complex (BABIgG) or BSA anti-BSA-mouse-F(ab')2 complex (BABF(ab')2), or BSA alone. An immunoperoxidase study for BSA showed that from 1 to 120 min after injection only BABIgG was ingested by both endothelial cells and Kupffer cells but not by hepatocytes. The staining intensity of BABIgG was maximal at about 15 min and decreased subsequently. Endocytosis of BABIgG occurred through coated pits in the endothelial cells. Within a few minutes, endocytosed BABIgG was found in tubulovesicular structures and large vesicles. The occasional large vesicles were shown to be lysosomes by simultaneous demonstration of BABIgG with acid phosphatase. BABIgG was not found on either of the endothelial and hepatocellular surfaces facing the space of Disse or in hepatocytes. These results indicate that soluble IgG-IC is endocytosed by sinusoidal endothelial cells and degraded in the lysosomes and that the participation of hepatocytes in the clearance of IgG-IC is improbable.