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Search for: rheumatoid arthritis    methotrexate    autoimmune disease    biomarker    gene expression    GWAS    HLA genes    non-HLA genes   

ID PMID Title PublicationDate abstract
1370619 Detection of stromelysin and collagenase in synovial fluid from patients with rheumatoid a 1992 Jan OBJECTIVE: To quantify stromelysin and collagenase in synovial fluid (SF) from patients with rheumatoid arthritis (RA) or traumatic knee injury. METHODS: Stromelysin and collagenase were measured in the SF of 33 patients with RA or posttraumatic knee injury, using specific double-antibody sandwich enzyme-linked immunosorbent assays. Stromelysin was fractionated from representative SF, and the molecular form was identified by immunoblot analysis. RESULTS: The stromelysin concentration was approximately 20-fold higher than the collagenase concentration in the fluids from patients with RA and approximately 8-fold higher in the fluids from patients with traumatic injury. For both metalloproteinases, there was a higher enzyme concentration in RA SF than in the SF from patients with trauma (stromelysin 40.1 +/- 26 micrograms/ml [mean +/- SD] in RA SF, 8.5 +/- 15 micrograms/ml in trauma SF; collagenase 2.2 +/- 3.3 micrograms/ml in RA SF, 1.1 +/- 2.3 micrograms/ml in trauma SF). The majority of the stromelysin within the SF bound to reactive red-agarose and was identified as prostromelysin based on electrophoretic mobility and immunoblotting with monospecific antibodies. CONCLUSION: The finding of high levels of stromelysin in SF from patients with RA supports the proposal that this enzyme may play a role in the connective tissue degradation observed in this disease.
7678534 Calcitonin gene-related peptide II, substance P and vasoactive intestinal peptide in plasm 1993 Jan Immunoreactive plasma and synovial fluid concentrations of calcitonin gene-related peptide II (CGRP II), substance P and vasoactive intestinal peptide (VIP) were measured in patients with osteoarthritis, gout and rheumatoid arthritis. Significantly higher levels of CGRP II and substance P-like immunoreactivity levels in synovial fluid were found in gout as well as CGRP II, substance P and VIP-like immunoreactivities in rheumatoid arthritis when compared to those in osteoarthritis. Plasma CGRP II, substance P and VIP-like immunoreactivity levels showed no significant differences among patients in the three different groups of arthritis. Our results suggest that these neuropeptides released from peripheral nerve endings into the synovial cavity probably play a pathogenic role in human joint inflammation.
8793258 Thrombocytopenia in patients with rheumatoid arthritis on long-term treatment with low dos 1996 May We reviewed the records of 315 patients with rheumatoid arthritis (RA) treated with low-dose methotrexate (MTX) and evaluated the conditions contributing to thrombocytopenia. Thirteen out of 315 patients with RA presented with low platelet counts (< or = 100,000/mm3). The age of these patients (51 +/- 12.6 years) did not correlate with thrombocytopenia (r = 0.211, p > 0.05). Thrombocytopenia resulted from coadministration of MTX and NSAID or multiple drug interactions. We observed a significant (r = 0.48, p < 0.05) increase of discontinuation of NSAID's but not of MTX therapy (r = 0.42, p > 0.05) with a mounting weekly dosage of MTX (12.5 +/- 5 mg orally). There was a significant correlation between this weekly dosage of MTX coadministered on the same day with NSAID and thrombocytopenia (r = 0.6, p < 0.05). In most cases (9/13) MTX was not or just temporarily withdrawn. Three of the remaining patients had multiple drug interactions. Reintroduction of low dose MTX treatment in patients having had thrombocytopenia could be performed safely, if thrombocytopenia occurred as a result of concomitant application of MTX and NSAID and no other multiple drug interactions. Preferably, MTX and NSAID should be given to these risk patients on separate days or intervals considering half time clearance of NSAIDs. This procedure has prevented the reoccurrence of thrombocytopenia and controlled further drug interactions of NSAIDs and MTX in our patients.
1371662 HLA-D region genes and rheumatoid arthritis (RA): importance of DR and DQ genes in conferr 1992 Jan The distribution of HLA-D region antigens was studied in three groups (I, IIa, and IIb) of patients with rheumatoid arthritis (RA): group I comprised 43 patients with mild, non-progressive RA, controlled by non-steroidal anti-inflammatory drugs without progression or erosions; group II comprised 94 patients with severe disease, who had earlier been treated with non-steroidal anti-inflammatory drugs and all had incomplete response requiring treatment with gold (sodium aurothiomalate). Of these, 46 patients (group IIa) responded to gold and the disease was well controlled, and the remaining 48 patients (group IIb) did not respond to gold and developed gold induced toxic reactions, including thrombocytopenia or proteinuria, or both. HLA-D region antigens were defined by serological and molecular (Southern blot analysis and oligonucleotide typing) techniques. The results show that DR4 was significantly increased in all three groups of patients. The prevalence of DR1, or DR1 in DR4 negative patients, and DR3 and DR4 associated DQw7 specificities, however, showed differences in these three groups of patients. The prevalence of DR1 and of DR1 in DR4 negative patients was increased only in patients with mild (group I) RA, but not in patients with severe (groups IIa and IIb) disease. On the other hand, the prevalence of DR4 associated DQw7 was significantly increased in patients with severe disease, but not in patients with mild RA. In addition, DR3 was significantly increased only in patients with severe disease who developed gold induced toxic reactions (group IIb). These data suggest that the HLA-D region genes which cause susceptibility to mild RA may be different from those causing susceptibility to severe RA. The results suggest that both DR and DQ (A, B) genes may be important in conferring susceptibility to RA: DR in mild disease and DQ in severe RA.
7575720 Hematologic and cytofluorographic analysis of patients with Felty's syndrome. A hypothesis 1995 Sep OBJECTIVE: To compare hematologic and cytofluorographic features in Felty's syndrome (FS) patients with and without the large granular lymphocyte (LGL) syndrome. METHODS: Peripheral blood cells from FS patients and from 2 control groups (rheumatoid arthritis [RA] patients and subjects without symptoms of a rheumatic disease) were analyzed by hematologic and cytofluorographic techniques. A separate assessment of disease activity was performed. RESULTS: FS patients had reduced lymphocyte and platelet counts, with a parallel reduction in lymphocyte subsets examined. CD4 counts were reduced in all FS patients, including those with the LGL syndrome. Disease activity was lower in FS patients than in RA control patients. Treatment was similar in all patient groups. No direct association was seen between LGL numbers and duration of RA or neutrophil counts in RA groups. CONCLUSION: Hematologic abnormalities in FS extend beyond neutropenia. Although similarities were seen between FS patients and FS patients with the LGL syndrome (e.g., CD4 lymphopenia), evidence for a gradation from FS to the LGL syndrome was not seen, thus favoring the hypothesis that a "transforming event" is required.
8571964 Sex influences on the penetrance of HLA shared-epitope genotypes for rheumatoid arthritis. 1996 Feb The association between rheumatoid arthritis (RA) and HLA DRB1 alleles may arise through linkage disequilibrium with a disease locus or the direct involvement of HLA alleles in RA. In support of the latter possibility, the shared-epitope hypothesis has been postulated, stating that conformationally similar DR beta chains encoded by several DRB1 alleles confer disease susceptibility. To examine these alternative hypotheses of marker-disease association and to investigate gender differences in RA susceptibility, we analyzed the distributions of PCR-based DRB1 genotypes of 309 Caucasian RA patients and 283 Caucasian controls. Initially, the marker-association-segregation chi 2 method was used to evaluate evidence for linkage disequilibrium and the direct involvement of markers DR4 Dw4, DR4 Dw14, and DR1 in RA susceptibility. Additional shared-epitope models that grouped DRB1 alleles into five classes (*0401, *0404/*0102, *0405/*0408/*0101, *1001, and all others) and postulated relationships between genotypes and RA susceptibility were also fitted to observed genotypic distributions by the method of minimal chi 2. For females, a linkage-disequilibrium model provided a good fit to the data, as did a shared-epitope model with RA most penetrant among individuals with the *0401,*0401 genotype. For males, the best model indicated highest RA penetrance among shared-epitope compound heterozygotes. Clinically, male RA patients had more subcutaneous nodules and greater use of slowly acting antirheumatic drugs, while female RA patients had earlier disease onset. This study therefore suggests that sex-related factors influence the RA penetrance associated with DRB1 shared-epitope genotypes and that DRB1 effects on RA prognosis and pathogenesis should be considered separately for men and women.
1566018 [Rheumatic fever. Its current status based on 4 cases]. 1992 Apr 11 We report on 4 patients with rheumatic fever hospitalized and investigated in our clinics within a 12 month period between 1990 and 1991. In each case a clinically non-severe sore throat preceded the outbreak of rheumatic fever. In three cases diagnosis was according to the revised Jones criteria. Polyarthritis was the only major symptom in these cases. One patient suffered from monarthritis. Minor symptoms were fever, arthralgia, elevated blood sedimentation rates and elevated values for CRP and for antistreptolysin O. The joint symptoms were treated with nonsteroidal drugs and subsided. One of the patients had a recurrence 9 months after the first attack even though correct secondary prophylaxis with a 4-weekly intramuscular regimen of 1.2 million units of benzathine penicillin was carried out. We discuss some epidemiological aspects and diagnostic difficulties resulting from a changing clinical pattern of the disease, and emphasize the need for streptococcal sore throat treatment and continuous secondary prophylaxis to prevent recurrences.
1289178 Risk of ulceration with long-term indomethacin: endoscopic and histological changes in upp 1992 Twenty patients taking long-term indomethacin were chosen for the study because all had a normal endoscopic examination; biopsies, however, from the oesophagus, gastric antrum and duodenal bulb revealed histological inflammation in all patients in at least one site. After 8 weeks during which indomethacin therapy was continued, a further endoscopy revealed lesions in 5 patients--peptic ulcer in 3 and erosions in 2--but only 1 of these had any change in gastro-intestinal symptoms. Irrespective of whether mucosal lesions are seen on endoscopy in patients established on non-steroidal anti-inflammatory drug therapy, they remain in danger of developing both ulcers and erosions which are likely to be asymptomatic. At no time can one justifiably feel this patient group is not at risk of peptic ulceration.
1371663 Different capabilities of monocytes from patients with systemic lupus erythematosus and rh 1992 Jan The effect of conditioned medium on the biosynthesis and glycosylation profile of acute phase proteins secreted by the human hepatoma cell line Hep G2 was studied. Conditioned medium was prepared from nonactivated [CM-LPS(-)] and ex vivo lipopolysaccharide activated [CM-LPS(+)] monocytes from eight patients with active rheumatoid arthritis (RA), five patients with active systemic lupus erythematosus (SLE), and seven healthy subjects. The biosynthesis of albumin, alpha 1-antichymotrypsin and alpha 1-proteinase inhibitor and the profile of glycosylation of proteinase inhibitor were analysed. CM-LPS(-) from patients with SLE had a similar effect to CM-LPS(-) from healthy subjects. In contrast, CM-LPS(-) from patients with RA had the same effect as CM-LPS(+) from healthy donors. A similar effect to that of CM-LPS(+) of healthy subjects was seen with CM-LPS(+) from patients with SLE and with CM-LPS(+) from patients with RA. The treatment of CM-LPS(+) with antibodies against interleukin 6 neutralised most of its ability to induce changes in the biosynthesis and glycosylation of acute phase proteins. Antibodies to interleukin 1 and tumour necrosis factor alpha had only a limited effect on the ability of CM-LPS(+) to induce changes of albumin and alpha 1-antichymotrypsin syntheses, whereas they had no effect on the biosynthesis and glycosylation of proteinase inhibitor. These results indicate that: (a) monocytes isolated from patients with active SLE and active RA have different capabilities of inducing alterations of acute phase proteins in vitro; (b) ex vivo activation of monocytes from patients with SLE leads to the full induction of its capabilities to change acute phase proteins, whereas the activation of monocytes from patients with RA has no additive effects; and (c) interleukin 6 seems to be a major cytokine involved in the regulation of the glycosylation pattern of acute phase proteins.
7593623 Nitric oxide production and inducible nitric oxide synthase expression in inflammatory art 1995 Nov In this study, we have identified the source of nitric oxide (NO) produced in the human inflammatory joints by analyzing expression of inducible NO synthase. In ex vivo organ cultures, both inflammatory synovium and cartilage from patients with rheumatoid arthritis produced NO. The NO production was suppressed by NG-monomethyl-L-arginine, an inhibitor of NO synthase. The amount of NO produced by the synovium correlated with the proportion of CD14+ cells in the corresponding tissue (r = 0.8, P < 0.05). Immunohistochemical analysis as well as in situ hybridization showed that inducible NO synthase was predominantly expressed in synovial lining cells, endothelial cells, chondrocytes, and to a lesser extent, in infiltrating mononuclear cells and synovial fibroblasts. The synovial lining cells and the infiltrating cells expressing inducible NO synthase were identified where CD14+ cells were located. Together with morphological features, this suggests that they are type A synoviocytes. NO production from freshly isolated synoviocytes and chondrocytes was up-regulated by in vitro stimulation with a combination of IL-TNF-beta, TNF-alpha, and LPS. In summary, the present results suggest that NO is produced primarily by CD14+ synoviocytes, chondrocytes, and endothelial cells in inflammatory joints of arthritides. NO production can be upregulated by cytokines present in inflamed joints. The increased NO production may thus contribute to the pathological features in inflammatory arthritides.
7532716 Immunohistological and functional analysis of adhesion molecule expression in the rheumato 1994 Nov OBJECTIVE: It has previously been shown that the adhesion of lymphocytes to microvascular endothelium mediates lymphocyte extravasation within inflamed synovium. After passing the endothelial barrier, binding of lymphocytes to matrix proteins and synovial lining cells may further lead to synovial membrane hyperplasia and subsequent cartilage destruction. Thus, we have explored the molecular basis of T cell-synovial lining cell interaction in the synovial membrane of patients with rheumatoid arthritis (RA). METHODS: Using an immunohistochemical staining technique and an in vitro frozen section assay we studied the expression and the role of several adhesion molecules in T lymphocyte-synovial lining cell interaction in the inflamed synovial membrane. RESULTS: In RA the macrophage-like (type A) synovial lining cells express high levels of intercellular adhesion molecule 1 [ICAM-1 (CD54)], whereas the fibroblast-like (type B) synovial lining cells predominantly express vascular cell adhesion molecule 1 (VCAM-1), in addition to moderate levels of ICAM-1. Both cell types express low levels of fibronectin. Unstimulated and anti-CD3 stimulated peripheral blood T cells bear the respective ligands lymphocyte function associated antigen 1 [LFA-1 (CD18/11a)], and very late antigen 4 and 5 [VLA-4 (CD29/49d) and VLA-5 (CD29/49e)]. T lymphocytes predominantly bound to type B synovial lining cells. Inhibition studies with monoclonal antibodies revealed that this binding involves the VLA-4/VCAM-1 and VLA-5/fibronectin (FN), but not the VLA-4/CS1 pathway. LFA-1 is also involved in this interaction via its ligand ICAM-1. CONCLUSION: These results show that the molecular basis of T lymphocyte binding to rheumatoid synovial lining cells is different from that described for T lymphocyte binding to synovial membrane vascular endothelium which involves the VLA-4/VCAM-1 and VLA-4/CS-1 pathways, but not the LFA-1/ICAM-1 pathway.
1543670 Rheumatic manifestations of neoplasia. 1992 Feb Neoplasia can be associated with a wide range of rheumatologic manifestations. Literature over the last 12 months has reviewed metastasis of solid tumors to the joint and hypertrophic pulmonary osteoarthropathy. Vasculitis has been reported as a paraneoplastic syndrome associated with both hematologic and solid malignancies. Paraproteinemia occurs in association with rheumatoid arthritis and may progress to lymphoproliferative malignancy. A careful review of 23 rheumatoid arthritis patients with a serum paraprotein has attempted to study the predictive value of monoclonal gammopathy in rheumatoid arthritis for the later development of lymphoproliferative malignancy. Rheumatic manifestations, including cutaneous vasculitis and lupuslike syndromes, are seen in up to 10% of patients with myelodysplastic syndromes. Leukemias sometimes present as synovitis, and immunocytologic analysis of joint fluids can help to establish the diagnosis of leukemic arthritis at an early stage. Several other cases reports of arthritis associated either directly or indirectly with neoplasia are presented.
1581487 Methods for estimating the parameters of a linear model for ordered categorical data. 1992 Mar In many empirical analyses, the response of interest is categorical with an ordinal scale attached. Many investigators prefer to formulate a linear model, assigning scores to each category of the ordinal response and treating it as continuous. When the covariates are categorical, Haber (1985, Computational Statistics and Data Analysis 3, 1-10) has developed a method to obtain maximum likelihood (ML) estimates of the parameters of the linear model using Lagrange multipliers. However, when the covariates are continuous, the only method we found in the literature is ordinary least squares (OLS), performed under the assumption of homogeneous variance. The OLS estimates are unbiased and consistent but, since variance homogeneity is violated, the OLS estimates of variance can be biased and may not be consistent. We discuss a variance estimate (White, 1980, Econometrica 48, 817-838) that is consistent for the true variance of the OLS parameter estimates. The possible bias encountered by using the naive OLS variance estimate is discussed. An estimated generalized least squares (EGLS) estimator is proposed and its efficiency relative to OLS is discussed. Finally, an empirical comparison of OLS, EGLS, and ML estimators is made.
1563033 Short-term effects of antirheumatic drugs. 1992 Feb Antirheumatic drugs fall into four categories: non-steroidal anti-inflammatory drugs (NSAIDs), slow-acting antirheumatic drugs (SAARDs), corticosteroids, and cytotoxic drugs. NSAIDs are useful in controlling the symptoms and signs of inflammation. They work within a few days but patients' response varies widely and is unpredictable. Hence there is a wide choice of agent. Anxiety about the side-effects of NSAIDs, particularly on the stomach and kidney, is growing and their use is likely to decline, especially in the elderly. SAARDs are being used increasingly early in the disease. It is realized that there is only a small window of opportunity (2 years) in which to get the disease into remission before irreversible damage is done to the joints. Thus, there is a growing tendency to use combinations of SAARDs together with steroids early in the disease. The most appropriate treatment for established RA (of more than 2 years duration) is less easy to discern. It is important to define realistic treatment goals on an individual basis and to tailor the medication accordingly. Cytotoxic drugs are still reserved for severe aggressive joint disease or for systemic manifestations. Once we are able to predict outcome more accurately, the stage will be set for a trial of combination chemotherapy in severe early RA.
8173849 A gastroscopic study of the predictive value of risk factors for non-steroidal anti-inflam 1994 May Peptic ulcer disease (PUD) in RA patients is associated with NSAID use. This study aimed to validate the predictive value of presumed risk factors for NSAID-associated PUD in a prospective gastroscopic study in RA patients. Eighty-one NSAID using RA patients were prospectively divided into four presumed risk groups according to Helicobacter pylori status and history of PUD. As additional risk factors the following were analysed: upper gastrointestinal GI complaints; disability; daily dose of NSAID and antral gastritis. The presence of PUD in the four risk groups did not differ. Additionally it was found that a history of PUD was predictive for current PUD [odds ratio (OR) 3.9; 95% CI 1.1-14]. H. pylori status was not predictive. Transformation from one ulcer type to another was rare. NSAID dose was not a risk factor, while disability was of borderline importance (OR 2.1; 95% CI 1-4.8). Current upper GI complaints were bad predictors. PUD only occurred with a concomitant antral gastritis. A history of PUD, disability and antral gastritis were the most important predictors for current PUD. When an ulcer relapsed it was of the same ulcer type as had been present earlier. This may have practical implications for prophylaxis enabling stratification by previous ulcer type.
1455397 Fibrinolytic potential and antiphospholipid antibodies in systemic lupus erythematosus and 1992 Nov 10 We studied the fibrinolytic response before and after venous occlusion (VO) in 30 patients with systemic lupus erythematosus (SLE), 25 with rheumatoid arthritis (RA) and 25 with different connective tissue disorders. Results were compared in patients with and without antiphospholipid antibodies (APA) and a history of either thrombosis or abortions. Before occlusion plasma levels of tissue-type plasminogen activator (t-PA) antigen and its inhibitor (PAI-1) were significantly higher in the patient group (p < 0.001). After occlusion, a low fibrinolytic activity on fibrin plates (p < 0.005) was observed in the same group. t-PA capacity and t-PA release were similar in relation to controls. The plasma PAI-1 activity was significantly elevated in each group of patients (p < 0.005) as compared to the control group. No significant differences with respect to t-PA and PAI-1 were observed in patients as to the presence or absence of thrombosis. There was also no correlation between the fibrinolytic changes and the presence of APA. It is concluded that an impairment of the fibrinolytic system, mainly related to increased PAI-1 levels, is present in most patients with connective tissue disorders, although these changes did not correlate with the presence of APA or the incidence of thrombosis.
7945472 Molecular cloning of a soluble form of the granulocyte-macrophage colony-stimulating facto 1994 Oct OBJECTIVE: To analyze the molecular and functional characteristics of a soluble form of the granulocyte-macrophage colony-stimulating factor receptor alpha chain (sGM-CSFR alpha), and analyze transcript expression in immune cells and the cellular constituents of rheumatoid arthritis synovial tissue. METHODS: We amplified, cloned, and expressed the sGM-CSFR alpha and transmembrane form of the receptor (tmGM-CSFR alpha) from complementary DNA derived from a human myelomonocytic cell line. Competitive polymerase chain reaction assays were developed to determine the absolute and relative amounts of tmGM-CSFR alpha versus sGM-CSFR alpha message synthesized by various cell lines and tissues. RESULTS: sGM-CSFR alpha transcripts were detected in bone marrow, monocyte/macrophages (cultured in GM-CSF), rheumatoid synovial tissue, and rheumatoid synovial tissue T cell lines, and represented the predominant transcript in synovial fibroblasts and osteoarthritis synovial tissue. Levels of expression in monocyte/macrophages and some synovial fibroblast and T cell lines approached those seen in transfected cell lines producing functional sGM-CSFR alpha. CONCLUSION: sGM-CSFR alpha represents a functional antagonist of GM-CSF activity in vitro. Expression of sGM-CSFR alpha in bone marrow, rheumatoid synovial tissue T cells, and synovial fibroblasts suggests an important role in vivo, both in regulating myelopoiesis and in modulating the immune response.
8431205 Proteolytic inactivation of alpha 1-antitrypsin and alpha 1-antichymotrypsin by neutrophil 1993 Feb OBJECTIVE: In vitro, activated neutrophils create a microenvironment in which proteinase inhibitors are inactivated through the coordinate action of reactive oxygen species and released elastase. We investigated whether such a mechanism may contribute to the destruction of the joint tissues in arthritis. METHODS: We analyzed the state of alpha 1-antitrypsin (alpha 1AT) and alpha 1-antichymotrypsin (alpha 1ACT), the two major inhibitors of the neutrophilic serine proteinases, in synovial fluid (SF) from patients with inflammatory arthropathies (n = 71) and osteoarthritis (OA) (n = 11), and related the results to neutrophil activation in SF. RESULTS: The ratio of functional to antigenic levels of alpha 1AT in SF of patients with inflammatory joint diseases was similar to that of alpha 1AT in normal plasma, whereas that of alpha 1ACT was significantly decreased. Patients with inflammatory arthropathies had significantly higher levels of inactivated alpha 1AT (i alpha 1AT) and inactivated alpha 1ACT (i alpha 1ACT) in SF (as determined with monoclonal antibodies specific for the inactivated [i.e., proteolytically inactivated and/or complexed] forms of these inhibitors) than patients with OA (P < 0.005). Inactivated alpha 1AT and i alpha 1ACT levels corresponded to 0.3-11% and 3-99%, respectively, of the total amount of these inhibitors in SF. Most of the i alpha 1AT in SF had a lower M(r) than that of native alpha 1AT. Inactivated alpha 1ACT in SF had an M(r) identical to that of nonfunctional alpha 1ACT in plasma treated with chymotrypsin. Levels of both i alpha 1AT and i alpha 1ACT correlated significantly with lactoferrin and elastase levels. CONCLUSION: These results suggest that alpha 1AT and alpha 1ACT in arthritic joints are inactivated in part by activated neutrophils, suggesting a role for these cells in impairment of the local balance between proteinases and their inhibitors in arthritis.
1597350 Detection of antibodies against streptococcal peptidoglycan and the peptide subunit (synth 1992 Serum antibodies reactive with streptococcal cell wall peptidoglycan (PG) and its peptide subunit (synthetic tetra-D-alanine) were measured by enzyme-linked immunosorbent assay (ELISA) in patients with rheumatoid arthritis (RA), juvenile rheumatoid arthritis (JRA), osteoarthritis and acute rheumatic fever (RF) compared with healthy subjects. Using 'checkerboard' titrations, anti-PG antibody in human serum was detected at a concentration of PG antigen at 10 micrograms per well with serum dilutions of 1:1,000. For measurement of anti-tetra-D-alanine antibody, the antigen, (D-Ala4)31 was used at 0.5 micrograms per well and sera were diluted to 1:200. When the IgG antibody levels to the PG and the tetra-D-alanine of the sera of patients with RA, JRA and RF were compared with sera from healthy subjects, the sera of the patients had significantly higher levels than did healthy subjects. Antibody that reacted with the PG in serum was absorbed with purified group-specific C-carbohydrate (A-CHO), but A-CHO was not capable of absorbing anti-(D-Ala4)31 antibodies. Therefore, the peptide subunit should be used as antigen in order to measure the specific antibody to PG. Both anti-PG and anti-tetra-D-alanine antibody in human sera primarily belonged to the IgG2 subclass.
7541816 Comparison of the sensitivity of different India inks staining of electro-blotted proteins 1995 Feb The sensitivity of different brands of India ink for staining proteins blotted onto filter membranes is described. Proteins that are electro-blotted onto filter membranes show better retention than those dot-blotted alone. Higgins engrossing waterproof black ink No. 893 can detect protein at a concentration as low as 5 ng which is much more sensitive than Coomassie blue. The nitrocellulose membrane from S&S is ideal for blotting proteins and gives low levels of background staining. The sensitivity of protein staining is however, affected by the types of India ink, ink concentrations, staining times and membrane lots. India ink is also found to be useful for staining circulating immune complexes separated by SDS-PAGE and electro-blotted onto filter membranes.