Convenient synthesis of DL-[1-11C]alanine.
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Alanine↗
Biomedical subjects
K Aho
Publications and source records attributed to K Aho.
Rheumatoid factors antedating clinical rheumatoid arthritis.
The relationship between rheumatoid factors (RF) and rheumatoid arthritis (RA) was studied in the Mini-Finland Health Survey. This covered a representative sample of the Finnish population over 30 years of age, initially comprising 8,000 persons, of whom 7,217 participated in the field survey carried out in 1978-80. The participants were followed using record linkage with the Social Insurance Institution's population register to identify patients entitled to free medication. Until the end of 1988, 21 persons had developed new seropositive RA. In 15 cases, preillness specimens contained elevated levels (greater than or equal to 20 IU/ml) of RF. In the remaining 6 cases with RF negative preillness specimens, the interval from taking the blood specimen to the onset of disease was 4 years or more. RF represent a key element in the rheumatoid inflammatory process. Their occurrence in preillness specimens suggests that they may have a primary role in the pathogenesis of the disease.
Adult↗
Measuring rheumatoid factor in nonrheumatoid subjects: immunoturbidimetric assay, latex slide test, and enzyme-linked immunosorbent assay compared.
Previous studies of patients with rheumatoid arthritis (RA) have shown a good correlation between results from immunoturbidimetric assays of rheumatoid factor (RF) and latex fixation tests. To extend the research to non-RA subjects, we tested sera from 1000 pregnant women, half each in the first and third trimesters. By turbidimetry, 24 non-RA sera were regarded as positive for RF (greater than or equal to 20 int. units/mL) and 18 sera as borderline (15-19 int. units/mL). By the latex fixation test, 28 non-RA sera gave a clear reaction (positive) and 17 sera a weak reaction (borderline). The association between the tests was statistically highly significant (P less than 0.001). All sera with positive and borderline reactions were tested by enzyme-linked immunosorbent assay for RF isotypes, together with a random subsample of about one-sixth of the original serum samples. Positive RF results by immunoturbidimetry were predominantly due to the presence of IgM-RF. In contrast to some earlier findings, we saw no difference in the prevalence of positive RF reactions between sera from the first and third trimesters.
Enzyme-Linked Immunosorbent Assay↗
Toxicity of D-lactate.
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Acidosis, Lactic↗
Occurrence of two germline-related rheumatoid factor idiotypes in rheumatoid arthritis and in non-rheumatoid seropositive individuals.
Human rheumatoid factor (RF) paraproteins express two distinct light chain cross-reactive idiotypes defined by the monoclonal antibodies 17.109 and 6B6.6. These germline gene-related cross-reactive idiotypes are both carried on VK3 light chains and are each present on about one-third of IgM RF paraproteins. We assessed the degree to which these idiotypes are represented in polyclonal RFs. We used rheumatoid arthritis (RA) and non-RA RF-positive sera selected from a large cross-sectional population study (the Mini-Finland Health Survey), and sera from a community-based follow-up study of recent-onset RA patients from Heinola, Finland. In the Mini-Finland Health Survey, elevated levels of the 17.109 RF idiotype were seen in sera of 13% of the RA and 19% of the non-RA group; 6B6.6 RF was seen in 26% of the RA and 28% of the non-RA group. In sera of the Heinola follow-up study, 17.109 RF was seen in 12% initially, but in only 3% at 8 years. Similarly, 6B6.6 RF was detected in 25% initially, but in only 7% at 8 years. Ten sera positive for RF prior to the onset of clinical RA were identified from individuals of a second large population study from Finland (North Karelia project); two of these sera exhibited the 6B6.6 idiotype; none exhibited the 17.109 idiotype. The data are consistent with the concept that these germline gene-related cross-reactive RF idiotypes occur frequently in the polyclonal RF of non-RA as well as RA sera, and that in RA the idiotypes may sometimes be reduced or lost as a consequence of somatic diversification of the RF through somatic mutation, usage of new germline genes, or both.
Arthritis, Rheumatoid↗
Smoking, lung function, and rheumatoid factors.
Positive rheumatoid factor (RF) reactions commonly precede the onset of clinically manifest rheumatoid arthritis (RA). Thus if items associated with RF reactions were traced at the community level this might provide clues to the cause of RA. The relations between smoking and lung functions and the occurrence of RA and RFs in a population sample representative of the adult Finnish population were studied. Rheumatoid factor testing was performed for 7124 subjects (89% of the sample) by the sensitised sheep cell agglutination test. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured with spirometry. 'False positive' RF reactions occurred twice as often in current smokers and ex-smokers than in those who had never smoked. The prevalence of high titres was fourfold greater among current smokers than among those who had never smoked. These associations were statistically significant and independent of age, FVC, and FEV1 in both sexes. The women with airflow limitation (FEV1/FVC less than 70%) had a significantly increased occurrence of RFs which was independent of their smoking history, but no such relationship was found in men. The results suggest an impact of smoking on RF production; a follow up study may show whether the raised RF titers in smokers will be reflected as an increased incidence of RA.
Adult↗
Antibodies to synthetic peptides from Epstein-Barr nuclear antigen-1 in sera of patients with early rheumatoid arthritis and in preillness sera.
We studied IgG antibody levels to synthetic peptides (p62, E11 and E3) from Epstein-Barr nuclear antigen-1 (EBNA-1) protein sequence in sera of patients with rheumatoid arthritis (RA), in pre-RA and in rheumatoid factor (RF) positive non-RA sera from Finland. Anti-E11 and anti-E3 antibody levels were significantly elevated in RA sera, compared with both RF negative and RF positive nonrheumatoid controls. The concentrations of anti-E11 and anti-E3 antibodies in the preillness sera were lower than those in RA sera. Eight-year followup samples of patients with RA had slightly decreased levels of anti-E3 and anti-E11 antibodies compared with samples taken within 6 months of the disease onset. Anti-p62 antibody levels did not differ significantly between any of the groups studied. Thus, elevated levels of antibodies to 2 of the glycine containing EBNA-1 peptides were associated with clinical RA.
Adult↗
Clinical arthritis associated with positive radiological and serological findings in Finnish adults.
The Mini-Finland Health Survey was designed to analyse the epidemiology of major public health problems. The study covered a representative sample of the Finnish population aged 30 years or over, and initially comprised 8,000 people. Serum rheumatoid factor was determined in 7,124 cases (89%). There were 138 cases of clinical arthritis in the series, corresponding to a prevalence of 1.9% (1.0% in males and 2.7% in females). Fifty-nine of the cases (0.8% of the population) were seropositive, and 50 cases (0.7%) had in their hand radiographs changes characteristic of rheumatoid arthritis. Twelve of the X-ray positive cases were seronegative. One-half of these proved to be seroconversion cases or rheumatoid variants typically seronegative, such as early-onset juvenile rheumatoid arthritis.
Adult↗
Serologic response against cardiolipin and enterobacterial common antigen in young patients with acute myocardial infarction.
Elevation of anticardiolipin antibodies has been observed in myocardial infarction and in many infections. To elucidate this topic, paired serum specimens from 40 patients with acute myocardial infarction were tested for anticardiolipin antibodies (solid-phase enzyme immunoassay) and enterobacterial common antigen antibodies (indirect hemagglutination test). Forty-one randomly selected individuals and 30 patients with chronic coronary heart disease served as controls. All individuals were males whose maximum age was 50 years. In patients with acute myocardial infarction the levels of anticardiolipin antibodies in paired sera rose significantly in all immunoglobulin classes (18% in the IgG class, 26% in the IgA class, and 43% in the IgM class), whereas no elevations occurred in the other groups. Fifteen of the acute myocardial infarction patients also showed at least a fourfold increase in enterobacterial common antigen antibodies, as compared with only one such increase in the two other groups combined. The increases were less marked than those seen in pronounced enterobacterial infections. These two reactions were closely associated.
Adult↗
Imaging of rats with mammary cancer with two 2-deoxy-2-[18F]fluoro-D-hexoses.
Rats with mammary cancer were imaged by scintigraphy: 10 rats with 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) and 10 rats with [18F]F-D-galactose. The uptake of both tracers was similar in the tumors--the tumor-to-normal tissue ratio was 2.7 +/- 1.1 for [18F]FDG and 2.3 +/- 0.9 for [18F]FDGal at 120 min after injection. In addition to the tumors [18F]FDG accumulated in the brain, bladder and heart, [18F]FDGal in the brain, bladder and liver. [18F]FDGal may be useful for tumor imaging in man; further studies should be addressed to elucidate the mechanism of [18F]FDGal uptake into tumors.
9,10-Dimethyl-1,2-benzanthracene↗
Bowel infection predisposing to reactive arthritis.
Postenteric reactive arthritis is one of several syndromes in which arthritis appears to be secondary to gastrointestinal tract pathology. A wide range of microbes may trigger this type of arthritis. On the other hand, there are differences between strains in their arthritogenic potential. Two possible mechanisms, not mutually exclusive, can be forwarded to explain these findings: first, particular characteristics of the infective organisms are necessary to initiate events leading to reactive arthritis and, second, particular anatomical locations and a certain degree of mucosal involvement are needed to initiate the process. Studies on humoral and cellular immune responses have not revealed any unifying feature that could explain the pathogenesis of reactive arthritis. The HLA allele B27 plays some kind of key role. Yet the elucidation of the fine structure of B27 specificity has not led to any immediate breakthrough in the understanding of the pathogenetic pathways. Experience of reactive arthritis associated with acquired immunodeficiency syndrome suggests that helper T cells are not involved. Antigen persistence may be connected with continuation of the inflammation. Recent developments in the serology of enteric bacterial infections will provide additional tools for uncovering the triggering agents in reactive arthritis. 'Idiopathic reactive arthritis' associated with clinically silent terminal ileitis is an interesting disease entity requiring further characterization.
Arthritis↗
Diet and physical activity of men in east and west Finland in 1969.
The purpose of the study was to discover the effects of physical activity on men's diets. The food consumption of 1306 men aged 50 to 69 years was studied using the dietary history method. The men were grouped in four classes according to their physical activity. With increasing activity their consumptions of cereals, potatoes, milk and milk products, fats and sugar increased. The men in East Finland used more milk, butter and fish than those in the West. The consumption of cereals, potatoes and eggs was higher in West than in East Finland. The intake of energy and energy yielding nutrients was greatly dependent on the physical activity but their contributions to the total energy intake were independent. The consumption of minerals and vitamins was adequate in all activity classes. The changes in the diet caused by physical activity seemed to be more quantitative than qualitative.
Aged↗
[Risk factors in cerebrovascular disease].
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Brain Ischemia↗
[Infection and cerebral infarction].
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Bacterial Infections↗
Antibodies against native type II collagen do not precede the clinical onset of rheumatoid arthritis.
Serum levels of IgG and IgM antibodies to native human type II collagen were determined in 22 pre-illness sera from subjects who developed seropositive rheumatoid arthritis (RA) 4 months to 5 years after sera were obtained, in 51 specimens from 35 healthy controls, and in 4-5 specimens from 58 patients with recent-onset RA. The antibody levels in all pre-illness serum specimens fell within the range seen for the healthy controls. Four RA patients had an IgG class antibody level and 4 had an IgM class antibody level that was above the highest level observed for controls, in at least 1 serum sample. No significant difference in the mean level of anticollagen antibodies was observed in the followup specimens from RA patients.
Adolescent↗
Significance of rheumatoid factors in an eight-year longitudinal study on arthritis.
A community-based cohort comprising 150 patients with recent-onset seropositive arthritis or seronegative oligoarthritis or polyarthritis was monitored for 8 years. Of the different rheumatoid factor (RF) tests, the initial positivity in the most sensitive assays (latex slide test and IgM-RF by enzyme immunoassay) was the most reliable factor when distinguishing between the erosive and nonerosive cases. The individual RF isotypes fluctuated in four serial specimens, but each patient tended to preserve his or her reactivity pattern. Seroconversion from positive to negative within the 1st year of follow-up did not indicate a particularly good long-term prognosis.
Arthritis, Rheumatoid↗
Anticardiolipin response and its association with infections in young and middle-aged patients with cerebral infarction.
Antibodies binding to solid-phase cardiolipin (anticardiolipin antibodies, ACA), which are closely associated with lupus anticoagulant activity, have been found in patients with thrombosis. ACA are often seen also in patients after acute infections. To study further our recent observation on the association between infection and cerebral infarction in young and middle-aged patients we measured anticardiolipin response (IgG, IgM, IgA) in paired sera from 54 consecutive patients with cerebral infarction under 50 years of age and in 54 community controls matched for sex and age. An elevated IgG-class ACA level or a significant change in level as observed in 2 serial samples occurred in 15 (28%) patients, but in only 4 (7%) controls (P less than 0.02). These ACA levels were only slightly elevated, and there were no patients with levels approaching values commonly seen in lupus anticoagulant-positive patients. Neither were there any patients with systemic lupus erythematosus (SLE) as an underlying disease. The combination of IgG-class ACA positivity and preceding probable bacterial infection (based on clinical, cultural or serologic data) was found in 10 patients (18%) but in only 2 controls (4%) (P less than 0.05). There were no significant differences in IgM- or IgA-class ACA between the patients and their controls. These results suggest that IgG-class ACA response associated with preceding probable bacterial infection is more common in patients with cerebral infarction than in their community controls. However, slightly elevated ACA are probably only indirect indicators of preceding infection and not directly involved in the pathogenesis of thrombosis itself.
Adolescent↗
Rheumatoid factor isotypes in patients with rheumatoid arthritis and in subjects with "false-positive" reactions.
The appearance of RFs, as detected by standard serological techniques, often precedes the onset of clinical RA by years. This pre-rheumatoid immunological reactivity is not associated with C-reactive protein response or occurrence of antibodies against native type II collagen. The profile of RF isotypes appeared to be similar between pre-rheumatoid and rheumatoid sera. RA sera contained somewhat more frequently IgG and IgA class RFs than "false-positive" sera from a community-based population sample. 7S IgM could be detected at about the same frequency in rheumatoid sera, in RF-positive pre-rheumatoid sera and in sera with "false-positive" RF reactions. The significance of the findings in terms of the pathogenesis of RA will be discussed.
Adult↗