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Biomedical subjects

M Pras

Publications and source records attributed to M Pras.

At least 109 records · Page 6Linked to original sources
PubMed1991

Characterization of high molecular weight amyloid A proteins.

Human amyloid A protein (AA) is usually composed of the NH2-terminal 76 amino acid residue of serum amyloid A protein (SAA), although lower and higher molecular weight fragments have been reported. We studied the primary structure of six AA proteins with molecular weights of 11 kDA-15kDA, as determined by SDS-PAGE. Automated Edman degradation of the intact purified proteins and sequence analysis of enzymatic peptides revealed that the AA proteins were composed of only 74 to 87 residues. Moreover, fragments of apolipoprotein E or histones 2a, 3 and 4 were associated with these AA molecules. Thus, AA heterogeneity may reflect diverse processing of the SAA precursor and a very close association with other proteins.

Amino Acid Sequence↗
PubMed1991

Crush and smear technique for rapid detection and semiquantitation of amyloid deposition.

A method using Congo red to rapidly identify and semiquantitate amyloid deposits in tissues for experimental research and clinical medicine is described. Examination by polarization microscopy revealed amyloid deposits as bright green birefringent clumps on a dark red background. On semiquantitative evaluation, good correlation was found between this technique and the conventional histological one, the present technique being more sensitive. The method described saves time and expense.

Amyloid↗
PubMed1991

Nocardia asteroides infection complicating rheumatoid arthritis.

We describe a case of pulmonary nocardiosis in a patient with rheumatoid arthritis (RA) receiving treatment with combined immunosuppressive agents and prednisone. This infection is still considered rare, hard to diagnose, and difficult to treat. To the best of our knowledge, such a case has not been described in a patient with RA.

Arthritis, Rheumatoid↗
PubMed1991

Tumor necrosis factor in familial Mediterranean fever.

PURPOSE: The pleiotropic inflammatory effects of tumor necrosis factor (TNF) prompted a study of this cytokine in familial Mediterranean fever (FMF), a recurrent polyserositis of unknown etiology. PATIENTS AND METHODS: Thirty-six asymptomatic and 24 patients with acute FMF were studied and compared with 20 matched healthy subjects. TNF levels were measured by bioassay in the plasma and in supernatants of peripheral blood mononuclear cells (PBMC) incubated alone or with an inducer (lipopolysaccharide, phytohemagglutinin [PHA], or Sendai virus). Cytotoxicity could be abolished in all cases by preincubation with monoclonal anti-TNF-alpha antibodies. RESULTS: No TNF was found in plasma and non-induced PBMC supernatants. Induced TNF production was markedly decreased in patients with acute FMF and increased in asymptomatic FMF patients to levels over those of control subjects (p less than 0.05). Thus, PHA-induced TNF levels were 4 U/mL in patients with acute FMF, 25 U/mL in asymptomatic patients, and 14 U/mL in healthy control subjects (median values), and the other inducers gave similar results. Retesting of patients first studied during an acute episode when their disease was quiescent also revealed a fivefold increase in TNF production. These results were independent of the use of colchicine, which also had no effect on TNF levels when taken by volunteers (1 mg/day) or when added to the PBMC cultures (10(-7) M). CONCLUSIONS: Since TNF has a very short half-life in plasma, the capacity of PBMC to respond to TNF inducers may more accurately reflect its synthesis. A marked decrease in this response in acute FMF suggests "exhaustion" of cells that are already highly activated to produce TNF and the possible participation of TNF in the pathogenesis of FMF.

Adult↗
PubMed1991

Determination of autoantibodies in patients with familial Mediterranean fever and their first degree relatives.

Sera samples of 168 patients with familial Mediterranean fever (FMF) and their 184 first degree relatives were analyzed for the presence of autoantibodies to ssDNA, dsDNA, poly (I), poly (G), cardiolipin, histones, RNP and Ro(SSA), using an enzyme linked immunosorbent assay (ELISA). A similar analysis was employed on culture fluids of Epstein-Barr virus (EBV) transformed B lymphocytes derived from patients with FMF and healthy controls. No increased incidence of these antibodies was observed among patients with FMF and their relatives compared to healthy controls. It is possible that autoimmune features observed in FMF are the result of nonspecific changes occurring in inflammation and not due to autoimmune mechanisms.

Antibodies, Antinuclear↗
PubMed1990

[Pulmonary disease induced by methotrexate].

A 68-year-old man with rheumatoid arthritis developed methotrexate-induced lung disease. He presented with fever, cough, respiratory distress and pulmonary infiltrates, which were initially mistaken for pneumonia. Alertness to this rare and dangerous complication of methotrexate treatment will reduce possible damage and help maintain its place as a leading medication for rheumatoid arthritis.

Aged↗
PubMed1990

Removal of sodium dodecyl sulphate from proteins isolated by sodium dodecyl sulphate polyacrylamide gel electrophoresis.

A procedure is described for the removal of sodium dodecyl sulphate (SDS) from proteins isolated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The proteins separated by SDS-PAGE were stained with Coomassie Blue and extracted with Tris-HCl buffer containing SDS. The obtained extracts were subjected to gel permeation chromatography in an acidic aqueous acetonitrile solution. The procedure allows purification of the isolated proteins not only from SDS, but also from Coomassie Blue, buffer salts and other small molecular weight contaminants.

Acetonitriles↗
PubMed1989

Bound amino acids in uremic sera: search for peptidic middle molecules by preparative polyacrylamide gel electrophoresis and high performance liquid chromatography.

The samples of normal and uremic sera were ultrafiltered, separated on SEP-PAK C18 cartridges and subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The serum material extracted from the slab gel was purified from SDS and further fractionated by reverse-phase high performance liquid chromatography (HPLC). The obtained fractions were examined by amino acid analysis and mass spectrometry. An increased number of moderately polar fractions containing bound amino acids was found in sera of uremic patients on hemodialysis. Two most prominent uremic fractions corresponded to N-benzoylglycine (hippuric acid) (fraction I, k' = 9,4) and phenylacetylglutamine (fraction II, k' = 9,7). Increased amounts of bound glutamine, glycine, serine, leucine, asparagine, alanine, valine, phenylalanine were found in other moderately polar uremic fractions. These fractions (k' range from 12.1 to 13.2) contained no free amino acids, nor any other known small uremic serum compounds; they were considered as peptide 'middle molecules' (MM) of a molecular mass smaller than 1700.

Amino Acids↗
PubMed1989

Systemic senile amyloidosis. Identification of a new prealbumin (transthyretin) variant in cardiac tissue: immunologic and biochemical similarity to one form of familial amyloidotic polyneuropathy.

Isolated amyloid fibrils from three cases of systemic senile amyloidosis (SSA) contained subunit proteins with molecular masses of 14 (10-20%), 10-12 (60-80%), and 5-6 kD (5-10%) when fractionated under reducing and dissociating conditions. This grouping was identical to that seen in SKO, a case of familial amyloidotic polyneuropathy (FAP) studied earlier. Amino acid sequencing confirmed that SSA subunit proteins were in fact prealbumin (transthyretin). Complete sequence analysis of one SSA preparation revealed the presence of a new variant Pa (TTr) molecule with a single amino acid substitution of isoleucine for valine at position 122. Further studies used an antiserum specific for SKO IV, a subunit protein of SKO previously shown to correspond to carboxy-terminal 78 residues (positions 49-127) of (TTr). Anti-SKO IV reacted with SSA in tissue at equivalent dilutions to anti-Pa (TTr) and with the 10-12-kD fraction of SSA on Western blots; reactivity was blocked by SKO IV, but not by Pa (TTr). SSA is a form of systemic amyloidosis caused by tissue deposition of Pa (TTr) and its fragments, with shared conformational or subunit antigenicity to at least one form of FAP. Identification of a new variant Pa (TTr) molecule in one case suggests further that SSA may be a genetically determined disease expressed late in life.

Amino Acid Sequence↗
PubMed1988

Antibodies against acetylcholinesterase and low levels of cholinesterases in a patient with an atypical neuromuscular disorder.

Antibodies against acetylcholinesterase were found in the serum of a patient presenting dyspnea, generalized muscle paresis, diminished tendon reflexes, and fasciculations. Electrodiagnostic studies showed a decremental response, an incomplete interference pattern, and reduced motor nerve conduction velocity. Edrophonium administration resulted in extreme cholinergic crisis. Biopsies displayed muscle atrophy and nervous tissue degeneration. Recurrent acute respiratory failure ended in death. The patient's serum pseudocholinesterase and red blood cells acetylcholinesterase levels were generally very low, with periodical fluctuations. Minute quantities of the patient's serum inhibited the activity of cholinesterases from normal human serum and from various fetal tissues. Enzyme inhibition was abolished following preadsorption of the serum immunoglobulins with goat antihuman Fab, and radioiodinated acetylcholinesterase from human erythrocytes was precipitated by the patient's serum, confirming that anticholinesterase antibodies were present. Acetylcholinesterase extracted from fetal striated muscle with detergent and salt was inhibited to a larger extent than the enzymes similarly prepared from other fetal tissues and more efficiently than buffer-soluble muscle enzyme. These findings suggest that the patient's serum contained antibodies which interacted preferentially with the membrane-associated forms of muscle acetylcholinesterase and indicate that autoantibodies against acetylcholinesterase could play a role in the pathogenesis of the disease.

Acetylcholinesterase↗
PubMed1988

Functionally reversible hepatic arteriovenous fistulas during pregnancy in patients with hereditary hemorrhagic telangiectasia.

Two patients with hereditary hemorrhagic telangiectasia (HHT) who previously had only rare episodes of epistaxis had during pregnancy congestive heart failure and signs consistent with hepatic AV shunts. These were confirmed by angiography in one patient. After delivery the patients recovered spontaneously, and within six months congestive heart failure disappeared.

Adult↗
PubMed1988

Serum and synovial fluid levels of serum amyloid A protein and C-reactive protein in inflammatory and noninflammatory arthritis.

Serum and synovial fluid (SF) levels of serum amyloid A (SAA) and C-reactive protein (CRP) were measured in 46 cases of various inflammatory arthritis (Group 1), and in 40 cases of noninflammatory arthritis: 18 cases of osteoarthritis (Group 2) and 22 cases of traumatic arthritis (Group 3). Serum and SF SAA levels were markedly elevated in Group 1: 126.4 micrograms/ml +/- 19.2 SEM and 46.4 micrograms/ml +/- 10.5 SEM, respectively; moderately elevated in Group 2: 10.1 micrograms/ml +/- 2.9 SEM, 4.0 micrograms/ml +/- 1.1 SEM and moderately elevated in Group 3: 10.4 micrograms/ml +/- 1.2 SEM, 4.0 micrograms/ml +/- 1.2 SEM, respectively. Serum/SF SAA ratios were similar in all 3 groups and ranged between 2.52-2.72. In comparison to SAA, the increment of serum and SF CRP above normal levels was moderate. A positive strong correlation was found between serum SAA and serum CRP: r = 0.64 (p less than 0.001) and between SF SAA and SF CRP: r = 0.59 (p less than 0.0001). SF SAA did not correlate with the number of SF white blood cells but did correlate with the percent of SF polymorphonuclear cells: r = 0.23 (p less than 0.05).

Arthritis↗