An extract of lionfish (Pterois volitans) spine tissue contains acetylcholine and a toxin that affects neuromuscular transmission

A soluble toxic extract derived from spine tissue of the lionfish (Pterois volitans) decreased heart rate and force of contraction in isolated clam and frog hearts. These actions were due to the presence of micromolar concentrations of acetylcholine in the extract. Toxicity was retained after hydrolysis of acetylcholine by exogenous acetylcholinesterase, but heart function was no longer affected. Toxin treated in this way induced muscle fibrillation in an isolated nerve-muscle preparation, followed by blockade of neuromuscular transmission. Bursts of transient depolarizations were recorded at the muscle endplate shortly after toxin addition that correlated in time with the duration of toxin-induced muscle fibrillation. These effects are thought to be due to the increased release and then depletion of acetylcholine from the nerve terminal.

Rapid separation of DNA restriction fragments using capillary electrophoresis

Open-tube capillary electrophoresis has been applied to the separation of restriction fragments of DNA with a Tris-borate buffer containing 7 M urea and 0.1% sodium dodecyl sulfate. The importance of sample pretreatment and of the injection of heated samples has been demonstrated. In one separation, a DNA restriction fragment mixture from 72 to 23,130 base pairs (DRIgestTM III) (molecular weight range from 4.6.10(4) to 1.5.10(7] has been electrophoresed in 10 min on a column of 15 cm effective length. Over 600,000 plates have been obtained for individual peaks. Several of the peaks have been identified, by spiking slab gel electrophoretically purified components. Other examples of restriction fragment separations are illustrated in this paper. The results of this study when further validated with full characterization of individual species, open up the possibility of rapid restriction enzyme mapping.

Rapid separation and purification of oligonucleotides by high-performance capillary gel electrophoresis

Picomole amounts of oligodeoxynucleotides [polydeoxyadenylic acids, (dA)40-60] were baseline resolved and analyzed in less than 8 min by high-performance capillary electrophoresis with polyacrylamide gels. In addition, fast analysis of a crude 70-mer oligodeoxynucleotide and a slab gel-purified 99-mer oligodeoxynucleotide was accomplished, demonstrating the ability of high-performance capillary electrophoresis to characterize rapidly synthesized oligonucleotides. Besides analytical separations, 800 ng of a primer (20-mer) was isolated in less than 20 min. The purified species was collected in water and subsequently used as a probe in a standard dot-blot analysis. The use of high-performance capillary electrophoresis for the analysis and purification of a variety of biopolymers is simple, rapid, and has the potential for automation.

Isolation and sequence analysis of amyloid protein AA from a patient with cystic fibrosis

This study represents the first sequence analysis of an amyloid fibril protein from a patient with cystic fibrosis. Although chronic infections are a hallmark of cystic fibrosis, secondary amyloidosis is a rare complication, and during the past 20 years, only 16 cases of amyloidosis in patients with cystic fibrosis have been reported. We examined amyloid fibrils isolated from the spleen of a 25-year-old man who had a history of a chronic cough since infancy and a diagnosis of cystic fibrosis at age 6 years. After solubilization in 6 mol/L guanidine and purification by gel filtration, the major component of the amyloid fibrils was a homogeneous 8000 dalton protein that reacted positively with antiserum to human amyloid A (AA) protein. Complete protein sequence analysis was carried out by using the whole protein and fragments obtained by treatment of the protein with cyanogen bromide, lysyl endopeptidase, and carboxypeptidase. The protein contained 76 residues and showed minor heterogeneity when compared with other AA protein sequences. The cystic fibrosis AA protein represents a product of the SAA-specific cDNA clone now known to be the alpha-allelic form of SAA1 in which valine is present at position 52 and alanine is at position 57.

The carbohydrate composition of human serum amyloid P component

The carbohydrate moiety of human serum amyloid P component was analyzed and found to consist of equal amounts of galactose and mannose (total 4.0%), of glucosamine and galactosamine in a ratio of 7:1 (total 2.7%) and sialic acid (3.9%). It should be noted that this is the first report on the separate quantification of the neutral hexoses and the demonstration of the presence of galactosamine. The contents of glucosamine and galactosamine suggest that this protein possesses both an N- and an O-glycan.

Metabolism of hexamethylene bisacetamide and its metabolites in leukemic cells

We investigated whether leukemic cell lines could convert hexamethylene bisacetamide (HMBA) to any of the metabolites previously identified and quantified in the urine and plasma of patients treated with HMBA. After 5-7 days of incubation with 1-2 mM HMBA, HL60 human promyelocytic leukemic cells, L1210 and P388 murine lymphoblastic leukemic cells, and Friend murine erythroleukemia cells contained 4 of the previously identified metabolites of HMBA. Gas chromatography/mass spectrometry confirmed the presence of N-acetyl-1,6-diaminohexane (NADAH), 1,6-diaminohexane (DAH), 6-acetamidohexanoic acid (AcHA), and 6-aminohexanoic acid (AmHA). Gas chromatography with nitrogen-phosphorus selective detection was used to quantify cellular concentrations of each metabolite. Cellular concentrations of AmHA and DAH were greater than those of NADAH and AcHA but no concentration of a metabolite exceeded that of HMBA. Metabolites were not detected in media from cells incubated with HMBA. Friend murine erythroleukemia cells that were resistant to HMBA contained only HMBA and NADAH. Moreover, the concentrations of NADAH in Friend murine erythroleukemia cells that were resistant to HMBA were less than those in the other cell lines studied. HL60 cells accumulated HMBA rapidly. NADAH, DAH, AcHA, and AmHA appeared sequentially in HL60 cells that were incubated with HMBA. NADAH appeared very rapidly, but concentrations of DAH were greater than or equal to those of NADAH by 8 h. AcHA and AmHA were not detected in cells before 24-48 h of incubation with HMBA. HL60 cells incubated with individual HMBA metabolites were able to accumulate each compound and to interconvert some: cells incubated with NADAH also contained DAH, AcHA, and AmHA; cells incubated with AcHA also contained low concentrations of AmHA; cells incubated with DAH also contained AmHA; and cells incubated with AmHA contained no other HMBA metabolites. HMBA was not present in cells incubated with any of its known metabolites. These results document the ability of various leukemic cells to metabolize HMBA, indicate the unidirectional catabolism of that compound, and may have implications as to its mechanism of action.

Differential expression of the amyloid SAA 3 gene in liver and peritoneal macrophages of mice undergoing dissimilar inflammatory episodes

The three active serum amyloid A (SAA) genes of mice, SAA 1, SAA 2, and SAA 3, are coordinately expressed in liver during acute and chronic inflammatory stimulation and experimental amyloidosis. The genes, primarily SAA 3, are also expressed extrahepatically. The apoprotein SAA 2 is the precursor of the amyloid A (AA) fibril protein that is deposited as insoluble fibrils extracellularly in spleen and other organs when amyloidosis occurs secondarily to inflammation. The exact cause of AA fibril formation is unknown. Amyloid enhancing factor is a high m.w. glycoprotein extracted from amyloidotic organs. Administration of amyloid enhancing factor alters experimental inflammation to bring about accelerated deposition of amyloid A fibrils first in spleen and later in other organs. In this study, hepatic and extrahepatic expression of the SAA genes were compared during accelerated amyloidosis relative to inflammation uncomplicated by amyloidosis. Differences in kinetics and pattern of SAA gene expression by resident peritoneal macrophages and liver were detected during four dissimilar inflammatory episodes. Macrophages expressed the SAA 3 gene solely, and to a greater extent in chronic than in acute inflammation. In accelerated amyloid induction, macrophage SAA 3 expression increased as SAA 1 and SAA 2 expression in liver decreased. However, alpha-1-acid glycoprotein expression remained elevated throughout the course of amyloid induction. The greatly increased expression of the SAA 3 gene by macrophages and decreased expression of the SAA 1 and SAA 2 genes in liver during amyloidosis, suggests that altered SAA gene expression may play a pathogenetic role in experimental amyloid deposition.

Differential expression of the amyloid SAA 3 gene in liver and peritoneal macrophages of mice undergoing dissimilar inflammatory episodes

The three active serum amyloid A (SAA) genes of mice, SAA 1, SAA 2, and SAA 3, are coordinately expressed in liver during acute and chronic inflammatory stimulation and experimental amyloidosis. The genes, primarily SAA 3, are also expressed extrahepatically. The apoprotein SAA 2 is the precursor of the amyloid A (AA) fibril protein that is deposited as insoluble fibrils extracellularly in spleen and other organs when amyloidosis occurs secondarily to inflammation. The exact cause of AA fibril formation is unknown. Amyloid enhancing factor is a high m.w. glycoprotein extracted from amyloidotic organs. Administration of amyloid enhancing factor alters experimental inflammation to bring about accelerated deposition of amyloid A fibrils first in spleen and later in other organs. In this study, hepatic and extrahepatic expression of the SAA genes were compared during accelerated amyloidosis relative to inflammation uncomplicated by amyloidosis. Differences in kinetics and pattern of SAA gene expression by resident peritoneal macrophages and liver were detected during four dissimilar inflammatory episodes. Macrophages expressed the SAA 3 gene solely, and to a greater extent in chronic than in acute inflammation. In accelerated amyloid induction, macrophage SAA 3 expression increased as SAA 1 and SAA 2 expression in liver decreased. However, alpha-1-acid glycoprotein expression remained elevated throughout the course of amyloid induction. The greatly increased expression of the SAA 3 gene by macrophages and decreased expression of the SAA 1 and SAA 2 genes in liver during amyloidosis, suggests that altered SAA gene expression may play a pathogenetic role in experimental amyloid deposition.

Plasma pharmacokinetics and urinary excretion of hexamethylene bisacetamide metabolites

In order to further understand the clinical toxicities of hexamethylene bisacetamide (HMBA) and to allow appropriate in vitro studies, we developed a suitable gas chromatographic assay and quantified plasma concentrations and urinary excretion of four metabolites which we had previously identified in urine of patients receiving 5-day HMBA infusions at 4.8-43.2 g/m2/day. 6-Acetamidohexanoic acid (AcHA) was the major plasma metabolite and reached steady state concentration (Css) by 24 h. AcHA Css increased from 0.12 +/- 0.02 (SD) mM at 4.8 g/m2/day to 0.72 mM at 43.2 g/m2/day. The Css AcHA:Css HMBA ratio decreased with increasing HMBA dosage. At dosages below 24 g/m2/day plasma Css of N-acetyl-1,6-diaminohexane (NADAH), the initial metabolite of HMBA, were below the limit of detection of our assay. With HMBA infusions of 24, 33.6, and 43.2 g/m2/day, Css of NADAH were 0.16 +/- 0.05, 0.14 +/- 0.06, and 0.19 +/- 0.04 mM, respectively. Css NADAH:Css HMBA ratios at 24, 33.6, and 43.2 g/m2/day were 0.18 +/- 0.06, 0.08 +/- 0.02, and 0.31 +/- 0.05, respectively. Plasma Css of 1,6-diaminohexane and 6-aminohexanoic acid were below the limit of detection of our assay. Each patient's urinary excretion of NADAH, AcHA, and 1,6-diaminohexane was consistent from day to day. The fraction of dose excreted in urine as AcHA was not affected by HMBA dosage and accounted for 12.7 +/- 3.9% of the daily dose. The percentage of daily HMBA dose accounted for by excretion of NADAH decreased with increasing HMBA dosage (10.8 +/- 6.0% at 4.8 g/m2/day to 4.2 +/- 1.2% at 33.6 g/m2/day). Urinary excretion of 1,6-diaminohexane always accounted for less than 3% of the daily dose. Our results indicate that: (a) plasma concentrations of AcHA alone cannot explain the degree of acidosis observed with toxic doses of HMBA; (b) NADAH is present in plasma at concentrations that we have found to cause differentiation in vitro; and (c) the probable rate-limiting step in HMBA metabolism is the initial deacetylation.

Production of an amino acid sequence-specific antiserum against human amyloid A (AA) and serum amyloid A (SAA) protein

The hydrophilic nonapeptide Ser-Asp-Ala-Arg-Glu-Asn-Ile-Gln-Arg, identical with residues 59-67 of human amyloid protein A (AA) and serum amyloid protein A (SAA), was covalently bound via its carboxyl-terminal end to the carrier-protein keyhole limpet haemocyanin. The complex was injected subcutaneously into ten rabbits. All rabbits produced antisera which, unabsorbed, were specific for AA and SAA. The antisera and their isolated peptide specific antibodies were performance-tested and found to be excellent for demonstration of AA and SAA in immunoblotting and immunohistochemical techniques but unsuitable for immunoprecipitation. Since it is difficult to produce AA- and SAA-specific antisera by procedures earlier described and commercial supplies of good such reagents are unavailable, the easy production of sequence-specific such antisera will facilitate more extended studies of the corresponding antigens for diagnostic and scientific purposes.

Hemodialysis-associated amyloidosis and beta-2 microglobulin. Clinical and immunohistochemical study

The beta-2 microglobulin type of amyloidosis was identified in articular and para-articular tissues of 14 patients with non-amyloid nephropathies undergoing long-term hemodialysis. Ten patients had carpal tunnel syndrome, 13 had juxta-articular radiolucent cysts (complicated by spontaneous fractures of the femoral neck in three), and six had destructive arthropathies of the large joints of the limbs. Massive amyloid deposits were found in the synovium, capsule, ligaments, articular cartilage, and/or bone. They were characterized by Congo red-induced green birefringence that was sensitive to potassium permanganate treatment. They reacted with anti-beta-2 microglobulin antiserum, whereas they did not react with antibodies directed against AA protein, prealbumin, or immunoglobulins. These data suggest that the potentially disabling arthropathy of hemodialysis is due to amyloid lesions. The persistently elevated plasma beta-2 microglobulin levels may play a role in the pathogenesis of this recently recognized complication, and if so, this complication should be preventable.

Lack of amyloid in abdominal fat aspirates from patients undergoing long-term hemodialysis

Recent reports describe the carpal tunnel syndrome (CTS) due to amyloid infiltration of the beta 2 microglobulin protein as a frequent complication of long-term hemodialysis. Carpal synovial and cystic bone lesion amyloid deposits have been reported; however, the extent of systemic amyloid deposition has not been determined. We examined 30 patients undergoing long-term hemodialysis for CTS and performed abdominal fat tissue aspiration for amyloid staining to evaluate the presence of systemic amyloid disease. In this group, CTS was frequent (37%) and its prevalence correlated with the duration of hemodialysis. In all patients, the abdominal fat tissue, stained with Congo red, was negative for amyloid deposits. These results confirm that CTS is a frequent complication of long-term hemodialysis; however, in this study, no detectable amyloid deposits were found in abdominal subcutaneous fat tissue. Thus, abdominal fat aspiration may not be a reliable screening test for hemodialysis-associated amyloidosis.

High-performance sodium dodecyl sulfate polyacrylamide gel capillary electrophoresis of peptides and proteins

High-performance capillary sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) has been developed for the separation and molecular weight (MW) determination of peptides and proteins. In this work, acrylamide was polymerized in fused-silica capillaries of 75 microns I.D. and 10 or 20 cm length. On-line UV detection was employed by placing the capillary in the optical path of the detector. Rapid separations of myoglobin fragments and of a mixture of standard proteins were demonstrated with efficiencies of the order of 40,000 plates for a column, 20 cm in length. Linear plots of log MW vs. mobility for the SDS protein complexes were observed. Variation in the percentage monomer composition (% T) of the polyacrylamide yielded the expected common intercept of log mobility vs. % T, confirming the size separation mechanism in the gel capillaries. The separation of the A and B chains of insulin with a 10-cm column in less than 10 min was also demonstrated.

Survival of patients with primary (AL) amyloidosis. Colchicine-treated cases from 1976 to 1983 compared with cases seen in previous years (1961 to 1973)

Primary amyloidosis has a variable course, but is generally associated with a short life expectancy. To date, no specific therapy has been available. Fifty-three patients with AL amyloidosis seen between 1976 and 1983 were treated with colchicine, and their clinical course and survival were compared with that in 29 other patients seen between 1961 and 1973. Of the variables measured, the treatment, the patient's sex, and the time interval from diagnosis to referral of treatment were significantly associated with length of survival. Median survival for the colchicine-treated patients was 17 months, compared with six months for the non-colchicine-treated patients. A surprising finding was the longer life span in female patients (median eight months versus four and a half months in the non-colchicine-treated group, and 25.5 months versus 10 month in the colchicine-treated group). The study suggests that colchicine has improved the life expectancy in AL amyloidosis. Although it is not a specific therapy, it may be a reasonable form of adjunctive treatment in this complex disorder.

Diagnosis of amyloidosis by abdominal fat aspiration. Analysis of four years' experience

Abdominal fat aspiration samples from 443 consecutive patients were examined for amyloid after Congo red and hematoxylin staining. Of the aspirates from 83 patients known to have systemic amyloid disease prior to the biopsy, 70 (84 percent) were found to yield positive results. The results for four aspirates from patients with localized amyloid disease were negative. Of the aspirates from 356 patients of unknown clinical status referred for analysis by outside physicians, 26 (7 percent) yielded positive results for amyloid. On review of the clinical records of these 26 patients, 11 had proved systemic amyloidosis demonstrated on biopsy of another site; all had a clinical course consistent with amyloid disease. In no case was amyloid found in a fat aspiration sample from a patient without clinical evidence suggestive of systemic amyloid disease. This study supports the proposal that abdominal fat aspiration is the diagnostic procedure of choice in the evaluation of amyloidosis since it requires no specialty consultation or technical expertise, causes minimal patient discomfort, and is accompanied by virtually no risk of morbid complication. A positive result has a high predictive value of amyloid disease in patients of unknown clinical status.

Sensitivity and specificity of the echocardiographic features of cardiac amyloidosis

Thirty-one patients with documented cardiac amyloidosis were compared to 39 control subjects with left ventricular hypertrophy to determine specific 2-dimensional echocardiographic features of amyloid. In 16 patients, increased myocardial echogenicity was present when a single short-axis view was examined, and had a sensitivity of 63% and a specificity of 74% for the diagnosis of amyloidosis. When complete echocardiograms were reviewed (15 patients), an improved sensitivity of 87% and specificity of 81% based on increased echogenicity was seen. Increased atrial septal thickness was present in 60% of amyloid patients and no controls. The combination of increased myocardial echogenicity and increased atrial thickness was 60% sensitive and 100% specific for the diagnosis of amyloidosis. The ratio of electrocardiographic voltage (S in V1 + R in V5 or V6) to left ventricular cross-sectional area also was examined. A ratio of less than 1.5 was 82% sensitive and 83% specific for amyloid (excluding the 2 patients with left bundle branch block), but added little to the diagnosis as determined from the 2-dimensional echocardiogram.

The induction of accelerated murine amyloid with human splenic extract. Probable role of amyloid enhancing factor

Amyloid enhancing factor (AEF) is derived from the tissues of pre-amyloidotic and amyloidotic animals and, when transferred, greatly accelerates amyloid induction in the recipient murine models. It has also been reported that similarly accelerated amyloid induction can be achieved in mice by injection of human splenic homogenates from patients with amyloidosis. The present study has attempted to characterize further the mechanism of this "heterologous transfer of amyloid". Treatment of mice with the "tissue homogenate" or the "AEF extract" of AA-, AL- and A prealbumin-laden human spleens followed by daily subcutaneous casein injections induced amyloidosis in an accelerated fashion. The resultant amyloid deposits in mice had strongly positive immunohistochemical reactions with anti-mouse AA, and negative reaction with anti-human AA or anti-human prealbumin. The results lend support to the idea that accelerated amyloid induction in the recipient mice is unlikely to be due to transfer of human amyloid substance, but rather to formation of "native" murine amyloid under the influence of a human AEF factor similar to or identical with AEF described in mouse-to mouse transfer models.

Renal amyloidosis. Evaluation by gallium imaging

A study has been performed to evaluate the efficacy of gallium imaging in the detection of renal amyloidosis. Ten of the 11 patients who had biopsy-proven renal amyloidosis demonstrated marked uptake in both kidneys. One patient revealed moderate gallium uptake in his kidneys. None of the patients had underlying renal or extrarenal pathology other than amyloidosis, which could account for renal gallium uptake (renal infection, neoplasm, hepatic failure or frequent blood transfusions). Four patients also had extrarenal foci of abnormal gallium uptake, suggesting other sites of amyloid deposits. Our data strongly suggest that gallium imaging has a high sensitivity for detection of renal amyloidosis. Its specificity is enhanced significantly by careful review of the clinical history to exclude other known causes of renal gallium uptake. Potentially, gallium imaging may be used to monitor the progress of patients under experimental therapy.

The association of an elastase with amyloid fibrils

The fibrils of all systemic forms of amyloid (primary, AL; secondary, AA; and hereditary, AF) that had been isolated by the water extraction procedure demonstrated elastolytic enzyme activity when examined in a specific assay using tritiated elastin. The source of this fibril-bound enzyme activity was consistent with human neutrophil elastase (HNE), since it was readily extracted by high salt solutions and inhibited by an elastase-specific chloromethyl ketone inhibitor, human alpha-1-protease inhibitor or by an antibody specific for HNE. The presence of an elastase on the amyloid fibril may suggest physiologic mechanisms of amyloid precursor protein degradation.

Isolation of the amyloid P component from the Engelbreth-Holm-Swarm (EHS) tumor of the mouse

The amyloid P component was isolated from the mouse EHS tumor, a producer of basement membrane-like material. Following collagenase treatment of the tissue homogenate and centrifugation, the supernatant was purified by calcium-dependent binding to agarose, and elution with ethylenediaminetetraacetic acid. Identification of the purified material as the amyloid P component was established by immunodiffusion and electron microscopic appearance as 8.5 nm pentagonal units, frequently assembled into columns. SDS-PAGE gel electrophoresis yielded 25,000 D bands, suggesting that the amyloid P is of the mouse type. It is proposed that the mouse amyloid P component extracted from the tumor is located within the basotubules present in the pericellular matrix.

Histochemical and immunohistochemical characterization of amyloid associated with chronic hemodialysis as beta 2-microglobulin

The carpal tunnel syndrome has been associated with amyloid deposits and is now regarded as a major complication in patients undergoing chronic hemodialysis. The hemodialysis-associated amyloidosis appears to have systemic rather than local involvement, although its full extent is yet to be determined. In an attempt to examine the chemical and immunologic nature of the amyloid, the authors carried out a series of histochemical and immunohistochemical studies with the following results. The amyloid was "sensitive" to the "permanganate treatment," suggesting it was the AA (secondary) type. On immunohistochemistry, however, anti-human AA did not give positive reaction with the amyloid deposits, suggesting that this would be a new form of amyloid. As reported elsewhere, the authors' preliminary results on the amino acid sequence analysis in one specimen have revealed homology of its amino terminal sequence to beta 2-microglobulin. In the present study, anti-beta 2-microglobulin did indeed react positively (with appropriate controls) with the amyloid deposits in the tissues collected from five different patients, confirming the beta 2-microglobulin-related nature of the amyloid. The present observations are significant in two points: (a) they confirm that hemodialysis-associated amyloid is of beta 2-microglobulin origin since it shares same antigenic determinant(s) with it and since the amino acid sequence is homologous; and (b) it adds what many have suspected, i.e., "permanganate-sensitive" amyloid is not specific for the AA type but includes AA and beta 2-microglobulin amyloid deposits at the minimum.

Serum amyloid A protein and C-reactive protein in systemic amyloidosis

In 106 patients with systemic amyloidosis (56 primary, 27 secondary, and 23 familial), serum amyloid A protein (SAA) was measured by solid-phase radioimmunoassay and C-reactive protein (CRP) was measured by rate nephelometry. SAA and CRP concentrations were highly correlated (r = 0.75, P less than 0.001) throughout the normal and abnormal concentration ranges. In systemic amyloidosis, SAA was more sensitive than CRP as an indicator of the acute-phase response, particularly in secondary amyloidosis. Acute-phase proteins are only occasionally increased during the course of familial amyloidosis. The overlap of acute-phase protein levels does not permit reliable separation of primary amyloidosis from secondary amyloidosis solely on the basis of such studies despite the significantly higher SAA and CRP levels in the latter.

In vitro formation of amyloid fibrils from intact beta 2-microglobulin

Prompted by the identification of hemodialysis-associated amyloid protein as beta 2-microglobulin, we attempted to create in vitro amyloid fibrils from the native protein. Beta 2-microglobulin in PBS was slowly dialyzed free of salt and then concentrated. The residue showed Congophilia with green birefringence by light microscopy and polarization, and non-branching fibrils of indeterminate length, measuring 8 to 10 nm in diameter by electron microscopy, thus meeting the morphologic criteria for amyloid. The present study demonstrates the first successful in vitro creation of amyloid fibrils with intact precursor protein molecules and provides supporting evidence that hemodialysis-associated amyloid is constituted from beta 2-microglobulin.

Isolation and characterization of a kappa amyloid fibril protein

The fibril in primary amyloidosis (AL) is composed of a monoclonal light chain or portions thereof. No unique primary structure has been identified that predisposes certain light chains to form amyloid fibrils. Currently, classification of amyloidosis is based on the biochemistry of the amyloid fibril. We determined the NH2-terminal sequence of an amyloid fibril and found it to be of the kappa I immunoglobulin subgroup. No structural alterations were detected to account for the conversion of the light-chain fragment to an amyloid fibril. Antiserum produced to the fibril protein did not react in immunodiffusion with purified LEP or MAG antigens, which are kappa I proteins. This antiserum may be directed to antigenic sites unique to the immunizing protein and is unable to recognize homologous proteins, rendering it unsuitable for immunochemical identification of amyloid deposits of light-chain origin. PAG represents the 10th reported variable kappa I amyloid fibril protein subjected to partial sequence analysis. Antisera that recognize antigenic determinants present in all members of an immunoglobulin subgroup need further development.

The clinical features of elderly-onset rheumatoid arthritis. A comparison with younger-onset disease of similar duration

Patients with elderly-onset rheumatoid arthritis (EORA) may represent a clinical subset of individuals who differ prognostically and therapeutically from patients with younger-onset disease (YORA). In order to test this hypothesis, we reviewed the records of 212 patients with rheumatoid arthritis and grouped them according to age at onset above or below 60 years old. Seventy-eight EORA patients and 134 YORA patients with disease duration of less than or equal to 10 years were used for a comparison of presenting features and disease outcome. Abrupt onset occurred somewhat more frequently in EORA, but was not associated with a significantly different clinical course than was an insidious presentation in this older group. There were no differences between the EORA and YORA groups in terms of mean initial joint score, although the scores for the YORA group had wider variation. An initial clinical presentation resembling polymyalgia rheumatica (PMR) was 4 times as frequent in EORA. Elderly patients were less likely to have subcutaneous nodules or rheumatoid factor at disease onset. At the final examination, the EORA patients had lower joint scores and higher health assessments despite similar courses of treatment. These outcome differences persisted when patients with PMR-like presentations were excluded. Multivariate analyses indicated that joint scores and disease duration made important contributions to a better outcome of EORA, whereas PMR presentation and abrupt onset did not. After an adjustment was made for these 4 features, age at onset was an important contribution to joint score outcome. These results confirm the existence of important differences in onset, clinical features, and prognosis between patients with EORA and those with YORA.

Esophageal manometry in familial amyloid polyneuropathy

The motility of the esophagus was studied by esophageal manometry in eight patients with familial amyloid polyneuropathy. All eight patients had an abnormality of the lower esophageal sphincter. Seven of eight had a borderline or decreased lower esophageal sphincter pressure and the other patient had a non-relaxing lower esophageal sphincter pressure. Six of eight patients had abnormalities of the body of the esophagus consisting of either simultaneous or decreased amplitude of contractions involving the smooth or striated muscle or both. In addition, seven of eight patients had diarrhea and six of these seven patients had evidence for steatorrhea. The manometric abnormalities observed were consistent with deposition of amyloid in smooth and striated muscle as well as in the enteric nervous system. Esophageal manometry appears to be a sensitive technique to determine if the gastrointestinal tract is involved in familial amyloid polyneuropathy.

Human serum amyloid A (SAA): biosynthesis and postsynthetic processing of preSAA and structural variants defined by complementary DNA

To study structural variants of human serum amyloid A (SAA), an apoprotein of high-density lipoprotein, complementary DNA clones were isolated from a human liver library with the use of two synthetic oligonucleotide mixtures containing sequences that could code for residues 33-38 and 90-95 of the protein sequence. The SAA-specific cDNA clone (pA1) contains the nucleotide sequence coding for the mature SAA and 10 amino acids of the 18-residue signal peptide. It also includes a 70 nucleotide long 3'-untranslated region and approximately 120 bases of the poly(A) tail. The derived amino acid sequence of pA1 is identical with the alpha form of apoSAA1. A fragment of pA1 containing the conserved (residues 33-38) region of SAA also hybridized with RNA from human acute phase liver and acute phase stimulated, but not unstimulated, mouse and rabbit liver. In contrast, a fragment corresponding to the variable region hybridized to a much greater extent with human than with rabbit or murine RNA. Human acute phase liver SAA mRNA (approximately 600 nucleotides in length) directs synthesis of preSAA (Mr 14 000) in a cell-free translating system. In a Xenopus oocyte translation system preSAA is synthesized and processed to the mature Mr 12 000 product. The complete 18 amino acid signal peptide sequence of preSAA was derived from sequencing cDNA synthesized by "primer extension" from the region of SAA mRNA corresponding to the amino terminus of the mature product. Two other SAA-specific cDNA clones (pA6 and pA10) differed from pA1 in that they lack the internal PstI restriction enzyme site spanning residues 54-56 of pA1.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin E1 inhibition of experimental amyloidosis in CBA/J mice

The antiinflammatory activity of systemically administered prostaglandin E1 (PGE1) was studied in experimental CBA/J mouse amyloidosis induced by chronic stimulation with silver nitrate. PGE1 lowered splenic deposition of amyloid A protein (AA) (p = 0.035). Serum amyloid A protein (SAA) levels were not suppressed by PGE1 in the acute phase, while decreased SAA levels appeared to be an integral part of the chronic inflammatory phase, with or without PGE1 treatment. Accelerated amyloid deposition induced by amyloid-enhancing factor (AEF) was not blocked by PGE1. This suggests that PGE1 inhibits amyloidosis in the predeposition phase, possibly by preventing formation of AEF or other deposition factors.

Effect of colchicine on experimental amyloidosis in two CBA/J mouse models. Chronic inflammatory stimulation and administration of amyloid-enhancing factor during acute inflammation

To investigate the mechanism of action of colchicine in blocking amyloid deposition, two model systems of amyloidosis in CBA/J mice were studied. In experimental chronic inflammation, daily injection of silver nitrate (AgNO3) resulted in the deposition of 667 +/- 68 ng of amyloid A protein (AA)/mg of spleen after 25 days. Treatment with 10 micrograms of colchicine daily decreased AgNO3-induced AA deposition to 12 +/- 1 ng of AA/mg of spleen (p less than 0.001). Colchicine diminished the acute phase serum amyloid A protein (SAA) response after 24 hours. Over a 25-day period, SAA concentrations declined and approached baseline both in colchicine-treated and (unexpectedly) in control mice. This suggested that suppression of SAA levels was not the primary event inhibiting amyloid deposition. In a model of accelerated amyloid deposition, injection of preformed amyloid-enhancing factor along with AgNO3 induced the deposition of 974 +/- 46 ng of AA/mg of spleen 48 hours later. Colchicine only partially decreased amyloid-enhancing factor-induced amyloid deposition to 578 +/- 91 ng of AA/mg of spleen, while blunting the acute phase SAA response. These results suggest that colchicine inhibits amyloidosis in the predeposition phase, possibly by blocking formation of amyloid-enhancing factor.

Lowered prealbumin levels in patients with familial amyloid polyneuropathy (FAP) and their non-affected but at risk relatives

Amyloid fibrils in familial amyloid polyneuropathy, the familial (AF) form of systemic amyloidosis, are composed of the monomeric unit (14,000 MW) of prealbumin molecules. By radioimmunoassay, the serum level of prealbumin was measured in 25 patients from 12 different kinships with this dominantly inherited form of amyloidosis and 56 unaffected, but at risk, relatives from two of the kinships. Results were compared to prealbumin levels in normal individuals and patients with primary (AL) and secondary (AA) forms of systemic amyloidosis. Significantly lowered prealbumin levels were found in the AF patients (149.2 micrograms/ml) and their at risk relatives (169.0 micrograms/ml) when compared to normal individuals (232.9 micrograms/ml), AL patients (221.9 micrograms/ml) and AA patients (211.7 micrograms/ml). No abnormality was found in levels of retinol binding protein (RBP), which is carried by prealbumin, in the serum of either the AF patients or their relatives. The depressed prealbumin levels may indicate a structural variant molecular form, an extra hepatic synthesis or an abnormality in catabolism of this protein that is present prior to the clinical or histopathologic onset of the AF disease.

Widespread occurrence of AP in amyloidotic tissues. An immunohistochemical observation

Plasma (P)-component of amyloid (AP or SAP), while not an integral part of the amyloid fibril, has been considered to be intimately associated with virtually every different type of amyloid. In the present study, we evaluated the distribution of AP in the organs frequently involved in two forms of human systemic amyloidosis (AA and AF) and in mouse AA amyloidosis, by use of immunohistochemistry with anti-AP. Although the amyloid deposits generally showed moderate reactions with anti-AP, they were not always clearly distinguished from the surrounding non-amyloid tissue elements which often stained as well. The basement membrane often showed even stronger reaction to anti-AP than the adjacent amyloid deposits, and liver sections demonstrated such a high overall reaction to anti-AP that the anti-AP reaction on the amyloid deposits was often obscurred. The present results suggest that the binding between AP and the amyloid fibril may not be monospecific, that AP by this technique occurs rather widely throughout the body, and therefore that anti-AP may not be considered as specific a marker for amyloid deposits in immunohistochemical and perhaps other studies as well.

Immunocytochemical study of hepatocyte synthesis of amyloid AA. Demonstration of usual site of synthesis and intracellular pathways but unusual retention on the surface membrane

For determination of the intracellular site of synthesis and the pathways followed by amyloid protein AA, immunocytochemical localization of the anti-AA reactive substance was investigated in the livers of CBA/J mice in an acute-phase response evoked by a single subcutaneous injection of 0.5 ml of 10% casein. In the cytoplasm of the hepatocytes, the positive reaction was localized on and/or in the rough endoplasmic reticulum and the single membrane-bound vesicles, vacuoles and lamellae including the Golgi apparatus, confirming that amyloid protein AA follows the common routes of synthesis and secretion established for other proteins. The anti-AA-reactive substance was also localized on the free surface of the hepatocyte membrane, including the microvilli. The latter reaction appeared as early as but lasted at least several hours longer than its cytoplasmic counterpart, suggesting that a certain retention period exists before the release of the AA-reactive substance from the cellular surface to the free blood plasma.

Primary (AL) amyloidosis as a cause of breast masses

Amyloidosis is rarely considered in the differential diagnosis of breast masses. During the past six years, 27 women with primary (24) and multiple myeloma-associated (three) amyloidosis (AL amyloid) were evaluated at our center. In five of these patients, amyloid was demonstrated on microscopic examination of breast tissue. The clinical presentations were similar to fibrocystic breast disease in two cases and malignancy in two others. Amyloidosis of the breast may be more common than previously recognized, especially considering the predilection of amyloid for depositing around fat cells. Therefore, pathologic examination of nonmalignant breast tissue should include Congo red staining and viewing under polarized light.

Cloning of human prealbumin complementary DNA. Localization of the gene to chromosome 18 and detection of a variant prealbumin allele in a family with familial amyloid polyneuropathy

Prealbumin, a 55,000 Mr protein, is a normal constituent of human serum. In patients with familial amyloid polyneuropathy (FAP), an autosomal dominant disease, variant prealbumin molecules are found in association with systemic amyloid deposits. One variant prealbumin has a methionine for valine substitution at amino acid 30 and has been implicated in the pathogenesis of type 1 FAP. A prealbumin-specific complementary DNA clone has been isolated from an adult human liver library and used in Southern blot hybridization experiments to identify a unique NsiI restriction endonuclease site in the variant allele carried by type 1 FAP patients with the methionine for valine substitution. The complementary DNA clone has been used to analyse a panel of human-mouse and human--hamster somatic cell hybrid DNAs and localize the prealbumin gene to chromosome 18.

Nephelometric measurement of human serum prealbumin and correlation with acute-phase proteins CRP and SAA: results in familial amyloid polyneuropathy

Prealbumin, a negative acute-phase reactant, has a role as a clinical index of patient status after inflammation, trauma, or surgery that is gaining recognition. We developed a rate nephelometric assay that allows quantitation of prealbumin levels in a large number of samples to be performed quickly, efficiently, and reproducibly. The generation of data by this method is more rapid and precise than the alternative measurement techniques of radioimmunoassay, radial immunodiffusion, and electroimmunoassay. Nephelometric analysis of serum prealbumin in 33 patients with familial amyloidosis showed significantly depressed concentrations compared with levels in normal individuals and in patients with primary and secondary amyloidosis. Prealbumin levels were compared with corresponding amounts of the acute-phase proteins C-reactive protein and serum amyloid A in the three amyloid groups. Lowered prealbumin concentrations corresponded to elevated levels of C-reactive protein and serum amyloid A in the sera from patients with primary and secondary amyloidosis. In the group with familial amyloidosis, however, the lower than normal levels of prealbumin did not correspond to elevations in C-reactive protein and serum amyloid A. Our data suggest that depressed plasma prealbumin concentrations noted in individuals with familial amyloidosis are not simply reflections of a negative acute-phase response.

Colchicine in acute inflammation: stimulation of production of interleukin-1 and modulation of the acute phase serum amyloid A protein response

The effects of colchicine on the acute phase serum amyloid A (SAA) response were studied in CBA/J mice to determine whether these effects are mediated via inhibition of interleukin-1 (IL-1) production. Prolonged pretreatment (72 h) with colchicine blunted the SAA response to stimulation with silver nitrate (AgNO3), while brief pretreatment (12 h) unexpected augmented SAA production. In a macrophage model, colchicine stimulated baseline production of IL-1 (SAA inducer and lymphocyte activating factor activities) and augmented lipopolysaccharide (LPS) induced IL-1 production. This indicates that colchicine does not inhibit amyloidosis via direct effects on early inducers of the acute phase SAA response.

Heterogeneous participation of the hepatocyte population in amyloid protein AA synthesis

Amyloid protein AA is believed to be synthesized in the liver in a form of its precursor, the acute phase reactant, SAA. To identify precisely the cell involved in SAA biosynthesis, immunohistochemical reaction to anti-mouse AA was analysed on the liver sections from CBA/J mice which had received a single casein injection and were sacrificed at predetermined times up to 48 hours. Two different primary localizations of the reaction were revealed. One was in the cytoplasm of certain hepatocytes. This reaction peaked at 6-8 hours after the casein injection in the intensity of the reaction and in the number of the cells involved. The hepatocytes with positive cytoplasmic reaction were scattered over the lobule and even at the peak did not exceed 20% of the total hepatocyte population. The other localization of the reaction covered linearly the surface of the hepatocyte cords, and peaked at 12-16 hours after the casein injection.