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Biomedical subjects

A M Teppo

Publications and source records attributed to A M Teppo.

At least 145 records · Page 8Linked to original sources
PubMed1983

The acute phase response and its relation to amyloid A degrading activity in serum of patients with rheumatoid arthritis undergoing arthroplasty.

The sequential changes in the concentration of specific serum proteins and their relation to amyloid A degrading activity were studied in ten patients with rheumatoid arthritis undergoing arthroplasty of the knee or hip. Serum amyloid A protein increased from a preoperative level of 78 +/- 20 gm/l (mean +/- SEM) to a peak level of 623 +/- 93 mg/l on the third postoperative day (P less than 0.001). The serum amyloid A protein response was greater than that of any other protein including C-reactive protein, to which it was closely related (r = 0.84, P less than 0.001). The concentrations of alpha 1-antitrypsin and alpha 1-antichymotrypsin were highest on the fourth postoperative day (mean changes + 35%, P less than 0.01, and +44%, P less than 0.05, respectively). Serum albumin, pre-albumin and alpha 2-macroglobulin behaved like negative acute phase reactants; the concentrations of albumin and alpha 2-macroglobulin were significantly decreased from the second to sixth and seventh postoperative days, respectively, and the concentration of pre-albumin was significantly decreased on the third and fourth postoperative days. A significant fall in the amyloid A degrading activity of serum occurred during the acute phase reaction. The degradative activity was lowest on the third and fourth postoperative days (P less than 0.001). The results show that the acute phase state in patients with rheumatoid arthritis induces a rise in the concentration of serum amyloid A protein, the putative serum precursor of tissue amyloid A fibrils, and a concomitant reduction in the ability of serum to degrade these fibrils. These factors together may be important in the development of inflammation-associated amyloidosis.

Acute Disease↗
PubMed1983

Do serine proteases degrade amyloid A fibrils?

Human serum contains enzyme(s) able to degrade serum amyloid A protein (SAA) and amyloid A (AA) fibrils. On the basis of inhibition tests these enzymes are regarded as serine proteases, but further characterization of the enzymes has, however, so far not been done. Chymotrypsin, trypsin, elastase, collagenase and kallikrein, when added to SAA-containing serum, all degraded SAA to peptides within 2 h at 37 degrees C. With the exception of collagenase these enzymes also destroyed the Sirius-Red-binding ability of amyloidotic tissue and that of isolated AA fibrils. Hence, they altered the conformation of the beta-pleated structure and possibly also degraded the fibrils. These results suggest that any of these serine proteases could be responsible of the degradation of SAA in serum. The enzyme concentrations needed to degrade amyloid fibrils, however, were much higher than normally found in serum. Thus, it is unlikely that the amyloid-fibril-degrading activity in serum could be due to any of these enzymes.

Amyloidosis↗
PubMed1983

No evidence of amyloidosis in type I diabetics treated with continuous subcutaneous insulin infusion.

A recent study has demonstrated secondary amyloidosis in dogs treated with continuous intravenous insulin infusion. Since elevated levels of serum amyloid A protein (SAA) and diminished amyloid fibril degrading activity (AFDA) are associated with amyloidosis, we measured SAA and AFDA in ten type I diabetics treated with continuous subcutaneous insulin infusion and in five conventionally treated patients. Only one pump- and one conventionally treated patient had detectable but low SAA levels, comparable with these seen in healthy controls. In patients with secondary amyloidosis the mean SAA level was 24-fold higher than in controls (P less than 0.001). Similarly, in both diabetic groups, AFDA was normal whereas it was reduced by 41% in patients with amyloidosis (P less than 0.001). Furthermore, no local amyloidosis was seen at the infusion site in any of the patients studied. Thus, our data fail to provide any evidence of secondary amyloidosis in patients treated for 3-40 mo with continuous subcutaneous insulin infusion.

Adult↗
PubMed1982

Mechanism of reduced amyloid-A-degrading activity in serum of patients with secondary amyloidosis.

Human serum contains amyloid-A-degrading (AADP) activity. This activity is reduced in amyloidosis associated with rheumatoid arthritis. Since AADP co-migrates with albumin on agarose-gel electrophoresis, the relationship between these serum factors was studied in patients with amyloidosis and patients with amyloidosis and patients with altered albumin synthesis and/or distribution. AADP activity correlated positively with albumin levels in patients with rheumatoid arthritis complicated by amyloidosis. A weaker association was noted between serum activity and prealbumin levels. The AADP activity in patients with rheumatoid arthritis without signs of amyloidosis and patients with liver cirrhosis was also positively associated with serum albumin level. During the acute-phase reaction after surgery serum AADP activity fell in parallel with serum albumin level. Purified albumin preparations displayed AADP activity. The results show that serum albumin level reflects AADP activity. It is suggested that the development of hypoalbuminaemia in patients with amyloidosis may give rise to a vicious circle which leads to an accelerated reduction in AADP activity and accelerated amyloidogenesis.

Adult↗
PubMed1982

Reduced amyloid-A-degrading activity in serum in amyloidosis associated with rheumatoid arthritis.

The ability to degrade amyloid A fibrils was studied in the serum of 31 patients with amyloidosis associated with rheumatoid arthritis, 33 patients with rheumatoid arthritis without amyloidosis, and 47 healthy controls. Fibrillar amyloid A protein and the radial diffusion method were used. The mean degrading activity in serum was significantly lower in patients with rheumatoid arthritis complicated by amyloidosis (58 +/- 19% SD of the activity in a pooled sample of sera from 100 healthy blood donors used as standard) than in patients with rheumatoid arthritis alone (78 +/- 14%; p less than 0.001) or controls (99 +/- 19%; p less than 0.001). Alpha 1-antitrypsin, concentrations of which were raised in both groups of patients, inhibited the degrading activity in serum even in low concentrations. A negative correlation between degrading activity and alpha 1-antitrypsin concentrations was observed. These findings suggest that reduced amyloid-A-degrading activity is due to inhibition rather than to deficiency of enzyme.

Adult↗
PubMed1982

Antibodies to SS-B in chronic inflammatory connective tissue diseases. Relationship with HLA-Dw2 and HLA-Dw3 antigens in primary Sjögren's syndrome.

SS-B antigen, purified from rabbit thymus, was used in an indirect enzyme immunoassay to demonstrate the presence of IgG-, IgA-, and IgM-type SS-B antibodies in sera from patients with well-defined and characterized chronic inflammatory connective tissue disease. High levels of antibodies to SS-B were found in patients with primary and secondary Sjögren's syndrome. Patients with Sjögren's syndrome secondary to systemic lupus erythematosus had significantly higher SS-B antibody values than patients with Sjögren's syndrome secondary to rheumatoid arthritis or patients with rheumatoid arthritis or systemic lupus erythematosus, alone. Two patients with rheumatoid arthritis without secondary Sjögren's syndrome also had a markedly elevated level of antibodies to SS-B. Antibodies of all immunoglobulin classes were found, although the highest values were either IgG- or IgM-type. In primary Sjögren's syndrome, antibody values to SS-B were higher in patients with HLA-Dw2 and/or HLA Dw3 than in those with other HLA-Dw types. We conclude that these antigens or specific immune-response genes close to the D region may be important for the development of antibodies to SS-B.

Antibodies↗
PubMed1982

Serum pepsinogen I in rheumatic diseases. Reduced levels in Sjögren's syndrome.

Group I pepsinogens were measured by radioimmunoassay in the sera of 93 patients with rheumatic diseases and 99 controls. Patients with rheumatoid arthritis and systemic lupus erythematosus had levels of pepsinogen I similar to controls, whereas patients with Sjögren's syndrome had levels significantly lower than either controls (P less than 0.001) or patients with rheumatic diseases not associated with sicca syndrome (P less than 0.001). The concentrations of serum pepsinogen I were lower in patients with sicca syndrome alone than in those with sicca syndrome associated with some other connective tissue disease (P less than 0.05). In patients with Sjögren's syndrome, a negative correlation was found between serum concentrations of beta 2-microglobulin and pepsinogen I (r = -0.46, P less than 0.05).

Adult↗
PubMed1982

Circulating DNA-antibodies in systemic lupus erythematosus.

Sera from 57 patients with systemic lupus erythematosus (SLE) were tested for DNA-antibodies by three different methods: a radioimmunological test using the Farr technique, the Crithidia luciliae immunofluorescence assay for anti-double-stranded (native) DNA (anti-ds-DNA), and a solid-phase immunoenzymatic assay for anti-single-stranded (denatured) DNA (anti-ss-DNA) of IgG and IgM classes. There was a positive correlation between the activity of the disease and the levels of ds-DNA-antibodies and IgG anti-ss-DNA. Patients with active nephritis had a higher amount of anti-ds-DNA and anti-ss-DNA of IgG class than patients with inactive nephritis (P less than 0.05 and 0.01, respectively). Patients with SLE nephritis had lower levels of ss-DNA-antibodies of IgM class than patients without nephritis (P less than 0.02). There was a positive correlation between the IgG-anti-ss-DNA/IgM-anti-ss-DNA ratio and the activity score of the disease. These results suggest that the anti-ss-DNA assay may be useful in the follow-up of SLE. Complement fixing anti-ds-DNA and the highest levels of anti-ds-DNA by Farr assay were usually associated with an active disease, especially nephritis and joint involvement.

Antibodies, Antinuclear↗
PubMed1982

Purification and characterization of a nuclear SS-B antigen.

A nuclear SS-B antigen was isolated from a saline extract of acetone powder of rabbit thymus by precipitation with ammonium sulphate, affinity chromatography with Blue Sepharose CL-6B, and preparative agarose gel electrophoresis. The mol. wt of the antigen was 68,000. Its electrophoretic mobility was similar to that of pre-albumin, and the iso-electric point was around pH 4.0. The main amino acids of the antigen were glutamic acid, leucine, lysine and alanine. Both histidine and tyrosine were also found. The purified antigen precipitated with anti-SS-B sera but not with any other reference antisera. It resembled La and Ha antigens in susceptibility to proteolytic and nucleolytic enzymes and to heat. The purified SS-B antigen, however, had a higher molecular weight than did the Ha and La antigens. The molecule could not be split into subunits with mercaptoethanol or acid. Counter-electrophoresis showed antibodies to the SS-B antigen in sera from patients with rheumatic diseases, including rheumatoid arthritis, systemic lupus erythematosus and Sjögren's syndrome, but not in amy of the control sera.

Adult↗
PubMed1982

Characteristics of the amyloid A fibril-degrading activity of human serum.

Radial diffusion in agarose gel containing amyloid A (AA) fibrils was used to study the serum enzyme capable of degrading AA fibrils in vitro. This degradative activity was unaffected by soya bean trypsin inhibitor, tosyl-lysine chloromethyl ketone, and gold thiomalate but was inhibited by bovine pancreatic trypsin inhibitor, phenylmethylsulphonylfluoride, diisopropyl fluorophosphate, alpha 1-antitrypsin, and alpha 2-macroglobulin, indicating that the enzyme involved is a serine protease. Agarose gel electrophoresis showed the enzyme to be an acidic protein with the same electrophoretic mobility as albumin. The molecular weight, measured by gel filtration, was approximately 50,000. The optimum pH of this enzyme was 7.3, and it was fairly heat-resistant. The results suggest that the AA-fibril-degrading activity in human serum is due neither to elastase nor to cathepsin G. It has many characteristics in common with the enzymes unlike elastase that are involved in the complete degradation of serum AA protein.

Adult↗
PubMed1982

Relationship between urinary sialylated saccharides, serum amyloid A protein, and C-reactive protein in rheumatoid arthritis and systemic lupus erythematosus.

The urinary excretion of sialic-acid-containing oligosaccharides, total sialic acid, serum amyloid A protein (SAA), and C-reactive protein (CRP) has been studied in 48 patients with rheumatoid arthritis (RA) and in 17 patients with systemic lupus erythematosus (SLE). Linear regression analysis revealed a close positive correlation between serum SAA and CRP levels in both RA (r = 0.71, p less than 0.001) and SLE (r = 0.86, p less than 0.001). The urinary excretion of sialyl lactose showed a positive correlation with the serum levels of SAA and CRP in RA (r = 0.45 and r = 0.45, respectively, p less than 0.01) but not in SLE (r = 0.05 and r = 0.10 respectively). Changes in serum total sialic acid levels paralleled those in CRP and SAA in RA as well as in SLE. Patients with very active RA had higher urinary sialyl oligosaccharide excretion (p less than 0.001), higher CRP levels (p less than 0.01), and higher SAA levels ( p less than 0.05) than those with moderately active disease.

Adult↗
PubMed1982

Immunoturbidimetry of albumin and immunoglobulin G in urine.

I describe a rapid, sensitive immunoturbidimetric assay for measuring urinary albumin and immunoglobulin G with use of an automated spectrophotometer. Diluted urine samples and polyethylene glycol in phosphate-buffered saline are pipetted into the cuvettes of the spectrophotometer. The initial absorbances of the samples are measured at 340 nm; antiserum to albumin or to immunoglobulin G is added to each tube, and after 2 min at 37 degrees C the absorbance of the mixtures is read at 340 nm. The initial blank absorbances of the samples are subtracted from the final absorbances automatically. The change in absorbance is linear with concentration in the range of 5-400 mg/L for albumin and 3-1000 mg/L for IgG. The lower limit of the determination is 5 mg/L for albumin, 3 mg/L for IgG. Linear correlations were observed between the concentrations of albumin and immunoglobulin G determined by this method (x) and those determined by radial immunodiffusion (y). The regression equation for albumin was y = 0.84x + 0.03 (r = 0.99, n = 87), and for IgG y = 0.94x + 0.02 (r = 0.98, n = 87).

Albuminuria↗
PubMed1981

Enzyme immunoassay of antibodies to Sjögren's syndrome B antigen.

I describe a solid-phase enzyme immunoassay of IgG-IgA-, and IgM-type antibodies to Sjögren's syndrome B antigen. Polystyrene tubes are coated with the purified antigen. The antibodies are allowed to bind with their antigens, and then detected with alkaline-phosphatase-conjugated anti-human IgG, IgA, or IgM sera. The amount of alkaline phosphatase fixed to the tubes is determined in pH 10.0 diethanolamine buffer at 37 degrees C with p-nitrophenyl phosphate as substrate. The absorbance of the p-nitrophenolate ion liberated in 1 h at 37 degrees C is measured at 406 nm. When rheumatoid factor is present, the values obtained for IgG antibodies are too low, and those for IgM antibodies are too high.

Antibodies↗
PubMed1980

Endogenous clearance rate and synthesis of alphafoetoprotein during and after blood exchange transfusion in hyperbilirubinaemic newborns.

Plasma alphafoetoprotein (AFP) concentration was monitored in 22 hyperbilirubinaemic infants during blood exchange transfusion at the age of 0-4 days, in order to determine the endogenous clearance rate and demonstrate possible postnatal synthesis of AFP. The rapid fall in plasma AFP during the transfusion to 19 +/- 4% (mean +/- S.D.) was followed by an increase to 81 +/- 15% of the initial concentration; only a 68% rise was expected after the establishment of a new equilibrium between the intra- and extravascular pools of AFP. Repeated transfusion in the same individuals gave similar findings. In two infants the total amount of AFP in these pools increased by 4.0-7.4 mg after the transfusions. The results could be accounted for by postnatal AFP synthesis. Because of the diffusion of AFP from the extravascular compartment to the intravascular pool the actual turnover rate of AFP could not be measured. The estimated magnitude of endogenous turnover rate of AFP, 0.02-0.09 min-1, gave a mean half-life of about 20 min, which is distinctly shorter than that of AFP in plasma (3-5 days); this could be due to either continuous synthesis of AFP or transfer of presynthesized AFP from the liver cells to extracellular pool. We postulate that either the synthesis or the turnover rate of AFP is controlled by the plasma AFP concentration via a negative feedback mechanism.

Birth Weight↗
PubMed1979

Heating at 56 degrees C does not eliminate immune complex-bound Clq.

The effect of heating at 56 degrees C on free and complex-bound Clq was studied by radioisotope and sucrose gradient centrifugation techniques. The ability of soluble complexes of egg albumin, rabbit anti-egg albumin, and human Clq to bind extrinsic iodinated Clq did not increase following heating at 56 degrees C. The results of this study did not support the postulated release of complex-bound Clq on heating at 56 degrees C. They also showed that free Clq was more heat-labile than Clq in the Clqrs state. The importance of elimination or monitoring of intrinsic Clq in Clq assays for circulating immune complexes is stressed.

Animals↗
PubMed1978

Binding affinity of human autoantibodies: studies of cryoglobulin IgM rheumatoid factors and IgG autoantibodies to albumin.

The binding affinity of cryoglobulin IgM rheumatoid factors (RF) for human IgG and of human IgG anti-albumin autoantibodies for HSA was measured by the molecular sieving technique. The binding affinities of the two autoantibodies were consistently low (10(4)-10(5) 1/M) as compared to the affinities of corresponding hyperimmune animal antibodies (10(6)-10(8) 1/M). The findings were discussed in relation to theories on human autoimmunity. The existence of strict autotolerance at the T cell level and of autoreactivity at the low affinity B cell level was considered to be best compatible with the findings of this study and with the major known facts of autoimmunity.

Antibodies↗