Late onset lattice corneal dystrophy with systemic familial amyloidosis, amyloidosis V, in an English family. (57/1787)

AIMS: To establish a clinical and molecular diagnosis in a family with late onset lattice corneal dystrophy. METHODS: Linkage analysis, single strand conformation polymorphism (SSCP) analysis, and direct sequencing of genomic DNA were performed. A review of the patients' clinical symptoms and signs was undertaken. RESULTS: Linkage to chromosome 9q34 was established and a mutation in the gelsolin gene was found in affected individuals. Numerous symptoms experienced by the patients were attributable to this mutation. CONCLUSION: A diagnosis of amyloidosis type V (familial amyloidosis, Finnish type, FAF/Meretoja syndrome/gelsolin related amyloidosis) was made. This is the first case of amyloidosis type V described in the UK. This emphasises the importance of recognition of the extraocular manifestations of eye disease both in the diagnosis and management of the patient. In addition, these findings can help molecular geneticists in their search for disease-causing mutations.  (+info)

Primary amyloidoma of the cervical spine. (58/1787)

Primary solitary amyloidoma of the spine is a disease characterized by localized deposits of amyloid. We describe and illustrate the radiologic appearance of primary solitary amyloidoma of the spine on plain radiographs, CT scans, and MR images. The imaging findings revealed features of a nonspecific soft-tissue mass with calcifications. Epidural extension of the amyloidoma caused spinal cord compression.  (+info)

alpha2-Macroglobulin, the main serum antiprotease, binds beta2-microglobulin, the light chain of the class I major histocompatibility complex, which is involved in human disease. (59/1787)

beta(2)-Microglobulin, a 12 kDa protein forming part of the class I HLA (histocompatibility locus antigen) major histocompatibility complex, has been used as a prognosis factor for multiple myeloma and as a marker of renal function, and has been shown to be involved in the pathogenesis of dialysis-related amyloidosis. alpha(2)-Macroglobulin has the ability to bind a wide range of physiologically important molecules, thereby influencing their metabolic impact. In this study we show by Western blotting analysis that beta(2)-microglobulin binds to alpha(2)-macroglobulin in vitro. This binding was confirmed by BIAcore analysis, and was shown by ELISA to be concentration-dependent. The sequences of the binding peptides in the mature beta(2)-microglobulin molecule were identified by Spot multiple peptide synthesis and alpha(2)-macroglobulin binding studies. In conclusion, beta(2)-microglobulin interacts specifically with the universal antiprotease a(2)-macroglobulin. The identification of this interaction brings into question some of the axioms on the metabolism of beta(2)-microglobulin, and may help to explain the clinical findings observed in b(2)-microglobulin-related diseases.  (+info)

Beta2-microglobulin and amyloidosis. (60/1787)

Dialysis-associated amyloidosis is a serious complication in chronic dialysis patients. Its clinical expression in terms of arthralgias, destructive arthopathies and carpal tunnel syndrome is often associated with amyloid deposits, which are mainly composed of beta2-microglobulin (beta2-M) fibrils, but in addition contain a number of other compounds. It is probable that beta2-M-amyloid deposition is related, at least in part, to the elevated plasma beta2-M that is characteristic of chronic renal failure. The latter can decrease with high-performance dialysis techniques but cannot be reduced to the normal range. Almost certainly, several other systemic and local factors are involved, including beta2-M transformed by advanced glycation end products and advanced oxidation protein products, serum P component, ubiquitin, calcium crystals, cytokines, immunoglobulin light chains, proteases and antiproteases, as well as modified collagen and glucosaminoglycans. It is also possible that the beta2-M protein, in its native or modified form, exerts noxious effects on bone and joint tissues, in addition to its mere 'passive' presence as amyloid fibrils. Several retrospective studies and one prospective study suggest that dialysis strategies with highly permeable, synthetic membranes and/or ultrapure dialysate may be partially protective or at least delay the onset of dialysis amyloidosis. Successful kidney transplantation generally halts the disease process and leads to rapid relief of osteoarticular pain although regression of beta2-M-amyloid deposits probably does not occur.  (+info)

'Carbonyl stress' and dialysis-related amyloidosis. (61/1787)

Advanced glycation end products (AGEs) are formed by nonenzymatic glycation and oxidation (glycoxidation) reactions. As AGE formation is related to hyperglycaemia, they have been implicated in the pathogenesis of diabetic complications. They also increase in normoglycaemic uraemic patients: AGEs, such as pentosidine and carboxymethyllysine (CML), are elevated in both the plasma proteins and skin collagen of uraemic patients, being several times greater than in normal subjects and nonuraemic diabetic patients. However, AGE concentrations do not differ between diabetics and non-diabetics in uraemia. AGE accumulation in uraemia, therefore, cannot be attributed to hyperglycaemia, or simply to the decreased removal by glomerular filtration of AGE-modified proteins as over 90% of plasma pentosidine and CML are linked to albumin. Recently, evidence has suggested that, in uraemia, the increased carbonyl compounds, derived from both carbohydrates and lipids, modify proteins both by the glycoxidation reaction (leading to augmented AGE production) and also by the lipoxidation reaction (leading to the augmentation of the advanced lipoxidation end product, ALE, production). Thus, uraemia might be a state of carbonyl overload with potentially damaging proteins ('carbonyl stress'). Carbonyl stress in uraemia appears to be relevant to long-term complications associated with chronic renal failure and dialysis, such as dialysis-related amyloidosis. Immunohistochemical studies, with specific antibodies to AGEs and ALEs, identified carbonyl stress in long-lived beta2-microglobulin amyloid deposits. Furthermore, proteins modified with carbonyl stress exhibit several biological activities through interactions with several types of cell, e.g. monocytes/macrophages, synovial cells and osteoclasts/osteoblasts, which might partially account for dialysis arthropathies.  (+info)

On-line haemodiafiltration. Remarkable removal of beta2-microglobulin. Long-term clinical observations. (62/1787)

BACKGROUND: The accumulation of beta2-microglobulin (beta2-M) in long-term dialysis patients may lead to dialysis amyloidosis. In this respect, the removal with different modes of on-line haemodiafiltration (HDF) of beta2-M was studied. Long-term clinical observations in patients with more than 10 years of dialysis, treated mainly with biocompatible and highly permeable membranes and in the last years with on-line HDF are also reported. METHODS: In the first part of this report, the reduction ratios and clearances of beta2-M, blood urea nitrogen, creatinine and phosphorus (P) of on-line HDF with 40 to 120 ml/min replacement fluid are compared with bicarbonate haemodialysis (HD). In the second part, we investigated 16 patients with more than 10 years of dialysis treatment. The prevalence of dialysis amyloidosis and the mean values for serum albumin, serum total cholesterol, HDL and LDL cholesterol and parathyroid hormone are reported, as well as the mean dose of erythropoietin. RESULTS: In the first part with on-line HDF, starting from HDF 60 ml/min a significantly higher beta2-M reduction ratio and clearance vs HD is noted. In HDF100 (i.e. with 241 replacement volume per 4-h treatment) vs HD, a beta2-M reduction ratio of 72.7% vs 49.7% (P= 0.0000) and a beta2-M clearance of 116.8 vs 63.8 ml/min (P=0.0000) was obtained. Comparing HDF120 with HDF100, there is a significantly higher beta2-M clearance with the former (P<0.005), although the beta2-M reduction ratio was not significantly better. In the HDF120 session the amount of beta2-M in the total dialysate was 292 mg per session. If one adds the known 17% adsorption on the polysulfone membrane, a total of 341.6 mg beta2-M per session is removed, which adds up to 1024.8 mg a week. Concerning the small molecules, our results with HDF100 also show a higher creatinine and especially P clearance vs HD. In the second part with 16 patients with more than 10 years of dialysis treatment (mean 14 years 1 month), the mean time on HDF amounted to 39.5% of the total treatment time. In four patients only biocompatible and highly permeable membranes were used, AN69 and mainly polysulfone, and in four other patients these membranes were used for more than 95% of the treatment time. Therefore, it is not surprising that the prevalence of carpal tunnel syndrome was only 12.5% in the patients after 10 years of dialysis. Twenty-five percent of these patients met the criteria for diagnosis of beta2-M bone-amyloidosis, proposed by van Ypersele de Strihou et al., but without a retrospective X-ray analysis. The mean predialysis beta2-M value was 29.6 mg/l. The mean values for serum albumin, serum total cholesterol, HDL and LDL cholesterol were within normal limits. For the parathyroid hormone a mean of 287.5 pg/ml was found. Subtotal parathyroidectomy was performed in five patients. The mean dose of 43 U erythropoietin/kg per session is comparable with those reported in the literature. Conclusions. Like Canaud, in our renal unit, treatment with on-line HDF with a highly permeable and biocompatible membrane has proven to be an efficient, well-tolerated and safe technique. Furthermore it leads to a low prevalence of dialysis amyloidosis and a superior P clearance. However, continuous attention must be paid to an on-line sterile and apyrogenic dialysate. Although on-line HDF is undoubtedly a more optimal approach of chronic dialytic treatment, it also carries a higher cost, which is currently evaluated to be nearly US$11 per session.  (+info)

Identification of a locus on chromosome 1q44 for familial cold urticaria. (63/1787)

Familial cold urticaria (FCU) is a rare autosomal dominant inflammatory disorder characterized by intermittent episodes of rash with fever, arthralgias, conjunctivitis, and leukocytosis. These symptoms develop after generalized exposure to cold. Some individuals with FCU also develop late-onset reactive renal amyloidosis, which is consistent with Muckle-Wells syndrome. By analyzing individuals with FCU from five families, we identified linkage to chromosome 1q44. Two-point linkage analysis revealed a maximum LOD score (Zmax) of 8.13 (recombination fraction 0) for marker D1S2836; multipoint linkage analysis identified a Zmax of 10. 92 in the same region; and haplotype analysis defined a 10.5-cM region between markers D1S423 and D1S2682. Muckle-Wells syndrome was recently linked to chromosome 1q44, which suggests that the two disorders may be linked to the same locus.  (+info)

Mutational analysis of the propensity for amyloid formation by a globular protein. (64/1787)

Acylphosphatase can be converted in vitro, by addition of trifluoroethanol (TFE), into amyloid fibrils of the type observed in a range of human diseases. The propensity to form fibrils has been investigated for a series of mutants of acylphosphatase by monitoring the range of TFE concentrations that result in aggregation. We have found that the tendency to aggregate correlates inversely with the conformational stability of the native state of the protein in the different mutants. In accord with this, the most strongly destabilized acylphosphatase variant forms amyloid fibrils in aqueous solution in the absence of TFE. These results show that the aggregation process that leads to amyloid deposition takes place from an ensemble of denatured conformations under conditions in which non-covalent interactions are still favoured. These results support the hypothesis that the stability of the native state of globular proteins is a major factor preventing the in vivo conversion of natural proteins into amyloid fibrils under non-pathological conditions. They also suggest that stabilizing the native states of amyloidogenic proteins could aid prevention of amyloidotic diseases.  (+info)