Soluble stem cell factor in human serum

Stem cell factor (SCF) is a recently described factor active in the early stages of hematopoiesis. It can exist in membrane-bound form and in proteolytically released soluble form. The levels and nature of SCF in human serum are described. As determined by an enzyme-linked immunosorbent assay performed for 257 samples, SCF level in serum averaged 3.3 +/- 1.1 ng/mL. The serum SCF was partially purified by immunoaffinity chromatography and analyzed by glycosidase treatments in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The results show that the SCF has N- linked and O-linked carbohydrate and corresponds to the soluble form, at or about 165 amino acids in length. The findings suggest functional importance for soluble SCF in humans.     

Circulating transferrin receptor in human serum

Circulating transferrin receptor has been detected in human serum with a sensitive immunoassay. The mean concentrations of the serum transferrin receptor in healthy males and females were 251 +/- 94 (mean +/- SD) ng/ml and 256 +/- 99 ng/ml, respectively. The serum receptor concentration in patients with haematological malignancies, including acute leukaemia, multiple myeloma and malignant lymphoma, varied widely, from normal to 1100 ng/ml. A single band with an approximate molecular weight between 80,000 and 100,000 daltons was obtained by polyacrylamide gel electrophoresis-immunoblotting analysis of serum.     

Soluble interleukin-2 receptor in Crohn's disease: relation of serum concentrations to disease activity.

Serum concentrations of soluble interleukin-2 receptor (sIL-2R) were measured as a marker of immune activation in a group of 30 patients with Crohn's disease. sIL-2R concentrations were determined by enzyme linked immunosorbent assay during periods of active and inactive disease and correlated with standard parameters of disease activity. Serum concentrations of sIL-2R were significantly raised in patients with active Crohn's disease compared with patients with inactive disease (p less than 0.001) and control subjects. There was a significant correlation between serum sIL-2R concentrations and disease activity as assessed by the Harvey-Bradshaw index (r = 0.42, p less than 0.01), platelet numbers (r = 0.49, p less than 0.01), and orosomucoid (r = 0.47, p less than 0.01), alpha 1 antitrypsin (r = 0.44, p less than 0.01), and C reactive protein concentrations (r = 0.48, p less than 0.001) but not with the erythrocyte sedimentation rate. Measurement of serum sIL-2R concentration is a simple and useful laboratory means of assessing disease activity. Raised concentrations in patients with active Crohn's disease is further evidence for in vivo immune activation occurring in this disease.     

Soluble interleukin-2 receptor in Crohn's disease

In Crohn's disease, the activity of the disease is sometimes difficult to evaluate and the evolution of the disease is difficult to predict. The soluble interleukin-2 receptor serum level has been reported to correlate with clinical activity of the disease and with mucosal immune activation. We compared serum soluble interleukin-2 receptor to classical inflammatory markers and other immune parameters in the assessment of clinical disease activity and prediction of relapse in patients with Crohn's disease. Soluble interleukin-2 receptor serum levels correlated well with the Crohn's disease activity index, and multivariate analysis showed that this correlation was independent of the other inflammatory and immune markers. The correlation was not greater, however, than that between some inflammatory markers, such as ESR, and Crohn's disease activity index. Longitudinal follow-up showed that a high soluble interleukin-2 receptor serum level was highly predictive of relapse. Multivariate analysis showed that the soluble interleukin-2 recepteur serum level was complementary to other inflammatory, and clinical markers in the prediction of relapse of disease. We conclude that soluble interleukin-2 receptor is of use in monitoring Crohn's disease, particularly in prediction of relapse.     

Soluble interleukin-6 receptor in rheumatoid arthritis

To investigate the pathophysiologic role of soluble interleukin-6 receptor (sIL-6R) in patients with rheumatoid arthritis (RA), serum sIL-6R levels were measured in 15 RA patients and 15 healthy control subjects using a sandwich enzyme-linked immunosorbent assay. Correlation analysis was performed between sIL-6R levels and clinical variables such as joint score, Lansbury’s index, C-reactive protein and platelet counts. Levels of sIL-6R and IL-6 were also measured in paired samples of serum and synovial fluid obtained at the same time from nine RA patients. Serum sIL-6R levels in RA patients (153.9±56.9 ng/ml) were significantly higher than those of control subjects (115.1±19.1 ng/ml;P<0.05). However, sIL-6R levels did not correlate with any clinical characteristic of RA. sIL-6R was detectable in synovial fluid, but was invariably lower than in serum, in contrast to IL-6 (i.e. much higher in synovial fluid). It correlated neither with total cell nor neutrophil number in synovial fluid. Serum C-reactive protein levels were significantly correlated with IL-6 in synovial fluid, but not with sIL-6R in synovial fluid. These results indicate that serum sIL-6R levels are increased in RA patients. High levels of serum sIL-6R did not seem to be derived from the site of local inflammation. The readily detectable sIL-6R in synovial fluid may co-operate with IL-6 in the pathogenesis of synovitis in RA.     

Soluble interleukin-6 receptor in rheumatoid arthritis

Abstract

To investigate the pathophysiologic role of soluble interleukin-6 receptor (sIL-6R) in patients with rheumatoid arthritis (RA), serum sIL-6R levels were measured in 15 RA patients and 15 healthy control subjects using a sandwich enzyme-linked immunosorbent assay. Correlation analysis was performed between sIL-6R levels and clinical variables such as joint score, Lansbury’s index, C-reactive protein and platelet counts. Levels of sIL-6R and IL-6 were also measured in paired samples of serum and synovial fluid obtained at the same time from nine RA patients. Serum sIL-6R levels in RA patients (153.9±56.9 ng/ml) were significantly higher than those of control subjects (115.1±19.1 ng/ml; P<0.05). However, sIL-6R levels did not correlate with any clinical characteristic of RA. sIL-6R was detectable in synovial fluid, but was invariably lower than in serum, in contrast to IL-6 (i.e. much higher in synovial fluid). It correlated neither with total cell nor neutrophil number in synovial fluid. Serum C-reactive protein levels were significantly correlated with IL-6 in synovial fluid, but not with sIL-6R in synovial fluid. These results indicate that serum sIL-6R levels are increased in RA patients. High levels of serum sIL-6R did not seem to be derived from the site of local inflammation. The readily detectable sIL-6R in synovial fluid may co-operate with IL-6 in the pathogenesis of synovitis in RA.     

Detection and quantification of soluble asialoglycoprotein receptor in human serum

We describe the first evidence that soluble asialoglycoprotein receptors (AGPR) are present in human serum and that they are quantifiable by an enzyme-linked immunosorbent assay (ELISA). An affinity chromatography gel immobilized with monoclonal antibodies (McAbs) against human liver AGPR was mixed with normal sera, and the bound fraction was analyzed both by sodium dodecyl sulfate polyacrylamide gel electrophoresis and by Western blot analysis. Immunoreactive bands corresponding to 35 to 40 kd were obtained, which were lower than those of liver AGPR (41 kd and 46 kd). Soluble AGPR in human serum was able to bind to d-galactoseimmobilized beads, indicating that the soluble AGPR remained ligand-binding activity. In order to quantify soluble AGPR, we established an ELISA using a monoclonal antibody (30220 McAb)-immobilized microplate and horseradish peroxidase-labeled F(ab′)₂ of another monoclonal antibody (30201 McAb). Reproducibility of intraand interassay of the ELISA were 4% to 14% and 7% to 14%, respectively. Analytical recoveries ranged from 93% to 99%. The detection limit was estimated to be 0.1 μg/ L. By nonparametolic analysis, a median and a 90% tile of serum AGPR level obtained from 283 normal volunteers were 0.4 μg/L and 2.4 μg/L, respectively.     

Soluble forms of the interleukin-6 signal-transducing receptor component gp130 in human serum possessing a potential to inhibit signals through membrane-anchored gp130

The interleukin-6 (IL-6) signal is transduced through membrane-anchored gp130, which is associated with IL-6 receptor (IL-6R) in the presence of IL-6. Soluble forms of gp130 (sgp130) with molecular weights of 90 and 110 Kd were found in human serum. In the presence of recombinant IL- 6 (rIL-6), serum sgp130 were capable of associating with serum sIL-6R. By the sandwich enzyme-linked immunosorbent assay, healthy human sera was shown to contain 390 +/- 72 ng/mL of sgp130. A mouse pro-B-cell line-derived transfectant, BAF-130, expressing human gp130 was used to examine the function of serum sgp130. When supplemented with rIL-6, human serum induced DNA synthesis in BAF-130 cells, whereas the serum deprived of sIL-6R did not. In contrast, the DNA synthesis induced in BAF-130 cells by rIL-6-supplemented serum was increased when the serum was deprived of sgp130. These results indicated that serum sgp130 could negatively regulate the IL-6 signal. Recently, gp130 has been shown to be involved in the signaling processes of oncostatin M, leukemia inhibitory factor, and ciliary neurotropic factor, in addition to those of IL-6. Recombinant sgp130 showed inhibitory effect on the biologic function of such cytokines. This work implies physiologic roles of naturally produced serum sgp130 in modulating signals through gp130.     

人体囊虫病诊断试剂盒的效果评价

目的评价囊虫IgG抗体检测试剂盒的诊断效果,为临床应用提供参考。方法按照囊虫IgG抗体检测试剂盒说明书,采用ELISA法检测囊虫病、包虫病、带绦虫病及健康人血清。结果在30例活动期脑囊虫病病人中,28例呈囊虫IgG抗体阳性,敏感性为93.33%。100份健康人血清均无阳性反应。在42例带绦虫感染者,2例囊虫抗体阳性,阳性率为4.76%。在60份包虫病血清中,阳性41份,该试剂盒与包虫病的交叉反应率为68.33%。结论所评价试剂盒敏感性较好,但特异性差,与包虫病的交叉反应率高。以上提示国内囊虫病免疫学诊断试剂的质量有待提高。     

Soluble elastin fragments in serum are elevated in aortic dissection

OBJECTIVES: We aimed to establish an enzyme-linked immunosorbent assay (ELISA) for measuring soluble elastin fragments (sELAF) in serum and to reveal its usefulness in diagnosing acute aortic dissection. BACKGROUND: Acute aortic dissection is a life-threatening disease of the aorta. However, the diagnosis is still frequently missed, especially at onset. The establishment and clinical availability of simplified laboratory test(s) to help diagnose and screen acute aortic dissection patients is therefore urgently needed. METHODS and RESULTS: An ELISA to measure sELAF in serum was developed using the newly created double monoclonal antibodies which recognize the different epitopes of human aortic elastin. Twenty-five acute aortic dissection patients, 50 patients with acute myocardial infarction, and 474 healthy individuals were enrolled in the study. The sELAF levels from healthy subjects gradually increased with aging. When the cutoff point for positivity was set at the mean + 3SD above the mean of those in healthy subjects at each age, 16 acute aortic dissection patients (64.0%) were found to be positive, while only one acute myocardial infarction patient was positive (2.0%). Acute aortic dissection patients with either an open or a partially open pseudolumen were found to be 88.9% positive for sELAF, while those with its early closure was 0% positive. The difference in the sELAF levels between acute aortic dissection patients with and without a thrombotic closure of false lumen was significant (60.3 +/- 15.6 vs 135.4 +/- 53.2 ng/ml, p < 0.005). CONCLUSIONS: The sELAF level in serum may be a useful marker for helping both diagnose and screen acute aortic dissection, while also helping distinguish acute aortic dissection from acute myocardial infarction.     

Soluble endothelial protein C receptor levels in healthy population

Increased levels of sEPCR lead to dysfunction of EPCR-mediated coagulation. The aim of this present study was to determine plasma sEPCR levels in a group of Turkish healthy population including both adults and children. The study population consisted of 230 healthy individuals (108 children and 122 adults) having no acute or chronic disease. Plasma sEPCR levels were measured with ELISA. Analysis revealed a bimodal distribution in both groups. There was a negative relationship between sEPCR levels and the age of individuals (r = −0.385, P = 0.0001). The sEPCR levels of children were found significantly higher than that of adults (P < 0.001). This study is the first study to determine the relationship of sEPCR levels and terms of age. Higher levels of sEPCR may suggest a regulation mechanism for the protein C anticoagulation system over the first years of life. Further studies should be conducted to evaluate the physiological importance and molecular mechanism of increased sEPCR levels in children.     

Soluble leptin receptor levels in patients with anorexia nervosa

OBJECTIVE: To examine whether changes of serum soluble leptin receptor levels (S-LEPR) can modify leptin half-life and its tissue effects. The aim of our study was to measure S-LEPR levels in patients with anorexia nervosa (AN) before and 6 weeks after partial refeeding. METHODS: Anthropometric variables, serum leptin, S-LEPR, insulin, cortisol and TNF-alpha were measured in 15 AN patients before and after partial refeeding and 15 healthy control women. RESULTS: S-LEPR levels in AN patients were significantly higher than in healthy subjects (26.8 +/- 8.1 vs. 16.36+/-2.6U/mL, p < 0.01) and were not affected by partial refeeding (26.8 +/- 8.1 vs. 24.2 +/- 6.1 U/mL). In contrast, body mass index (BMI), body fat content, and serum leptin levels in AN patients increased significantly after partial refeeding. Except for the inverse relationship of S-LEPR levels to BMI and body fat content no clear relationship of this parameter to serum leptin, cortisol, insulin or TNF-alpha was found. CONCLUSION: S-LEPR levels are significantly increased in AN patients and this increase is unaffected by partial refeeding. The possibility of etiological role of increased S-LEPR levels in AN patients by affecting leptin central and/or peripherial effects should be further elucidated.     

Soluble interleukin-2 receptor in juvenile rheumatoid arthritis.

Juvenile rheumatoid arthritis (JRA) is a chronic, relapsing, inflammatory childhood disease characterized by arthritis and systemic inflammation. At present there is no rapid, efficient laboratory method of assessing disease activity and degree of immune activation. We measured serum soluble interleukin 2 receptor (sIL-2R) levels in 85 samples from 72 patients (22 samples from patients with systemic JRA, 34 from polyarticular patients, 29 from pauciarticular patients, of which 10 were HLA-B27 positive). The mean sIL-2R level from patients was 1565 U/ml, which is significantly elevated compared to control values of 594 U/ml (p less than or equal to 0.005). The highest levels were seen in patients with systemic JRA (mean value 2121 U/ml) while the lowest values were seen in HLA-B27 positive (+) patients (mean value 899 U/ml). Patients with clinically active disease had significantly elevated levels (mean value 1745 U/ml) compared to patients with inactive disease (mean value 846 U/ml, p less than or equal to 0.01). Highest levels were seen in patients with active systemic JRA (mean value 2419 U/ml) while patients with pauciarticular JRA and B27 + JRA had the lowest sIL-2R levels (1167 and 1045 U/ml, respectively). sIL-2R levels were elevated in all subgroups of clinically active patients compared to controls (p less than or equal to 0.0005). Three of the 4 patients with serial sIL-2R measurements showed falling values during the period of clinical remission. Using regression analysis and likelihood ratio tests, we found a significant correlation between sIL-2R levels and both disease activity and joint count (p less than or equal to 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)