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Enzyme-linked Immunoassay (enzyme-linked + immunoassay)
Selected AbstractsSerum osteoprotegerin is increased in Crohn's disease: A population-based case control studyINFLAMMATORY BOWEL DISEASES, Issue 4 2005Charles N Bernstein MD Abstract Background: There is a potential interface between osteoporosis and the chronic inflammation of inflammatory bowel disease (IBD), and the osteoprotegerin (OPG)/receptor for activated nuclear factor-,B (RANK)/RANK ligand (RANKL) signaling pathway may be an important mediator, although data are limited. Methods: We conducted a population-based case-control seroassay study to look for alterations in serum OPG and soluble RANKL (sRANKL). The study population included IBD patients who were 18 to 50 years old with Crohn's disease (CD; n = 287) or ulcerative colitis (UC; n = 166), age-matched healthy controls (n = 368), and nonaffected siblings of IBD patients (n = 146). Serum OPG and sRANKL were measured by enzyme-linked immunoassay. Sex-specific reference ranges were derived from the healthy controls. Results: Analysis of variance (ANOVA) confirmed significant group differences in women for mean serum OPG (P = 0.018). CD women had higher values of OPG than UC women (P = 0.028) or healthy controls (P = 0.045), whereas the other groups were similar. OPG levels were above the reference range in 13/173 (8%) of CD women, exceeding the expected proportion (P = 0.032). In contrast, no differences in OPG were seen in men between controls, CD, or UC. Estrogen use in women (P = 0.000002) and corticosteroid use in men (P = 0.026) were associated with higher OPG levels. In multivariate analysis, CD diagnosis (P = 0.031) and estrogen use (P = 0.000002) were independently associated with higher OPG levels. No group differences were seen in mean serum sRANKL measurements. Conclusions: An OPG:sRANKL imbalance with OPG exceeding sRANKL should inhibit osteoclastogenesis and promote bone formation. CD is associated with increased fracture risk, and possibly, the paradoxically higher OPG is a counterregulatory response to factors such as inflammatory cytokines, promoting high bone turnover. Alternatively, elevated OPG in CD may reflect T-cell activation. [source] Anti-C1q antibodies: association with nephritis and disease activity in systemic lupus erythematosusJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 1 2009Carlos Geraldo Moura Abstract Background: Anti-C1q antibodies have been described in systemic lupus erythematosus (SLE) as well as in other connective tissue diseases. They have been considered as a marker for disease activity and presence of nephritis. Objective: The aim of this study was to determine the prevalence of anti-C1q antibodies in Brazilian lupus patients as well as analyze their association with different clinical and serologic parameters. Methods: Sera from 81 SLE patients, based on the American College of Rheumatology (ACR) criteria, were collected from a lupus referral outpatient clinic in Salvador, Brazil. Antibodies to C1q were detected by an enzyme-linked immunoassay (ELISA) kit and antibodies to other cellular antigens identified by indirect immunofluorescence on HEp-2 cell substrate (ANA), or Crithidia luciliae (dsDNA), and to nucleosome by ELISA. A cutoff of 20,U wasestablished for anti-C1q and antinucleosome assays. Results: Anti-C1q antibodies were detected in 39.5% (32/81) of SLE sera. The presence of anti-C1q antibodies was associated with proteinuria (P=0.028) but not with other laboratory or clinical features, such as antinucleosome or anti-dsDNA antibodies, hematuria, urinary casts or renal failure, leukopenia, pericarditis, pleuritis, malar rash, seizures, and psychosis. There was a positive correlation between the titers of anti-C1q antibodies and the systemic lupuis erythematosus disease activity index (SLEDAI) score (r=0.370; P=0.001). Conclusion: This study in Brazilian SLE patients confirms previous findings of the association of anti-C1q antibodies with nephritis and disease activity. J. Clin. Lab. Anal. 23:19,23, 2009. © 2009 Wiley-Liss, Inc. [source] Detection of ciguatoxin in fish tissue using sandwich ELISA and neuroblastoma cell bioassayJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2008Cara Empey Campora Abstract The applicability of a new enzyme-linked immunoassay (ELISA) for detecting ciguatoxin (CTX) in fish tissue was evaluated by testing three fish species commonly implicated in ciguatera fish poisoning in Hawaii. A total of 164 individual almaco jack (Seriola rivoliana) and greater amberjack (S. dumerili) and a total of 175 individuals of the blue-spotted grouper (Cephalopholis argus) were caught at various locations in the Hawaiian Islands. Muscle tissue from each individual was assessed for the presence of CTX using two methods: a semi-quantitative ELISA that was recently developed for detecting picogram levels of CTX in fish extract and a neuroblastoma (NB) cell assay commonly used to screen for marine toxins in fish. Results of the tests were highly correlated, with the ELISA indicating the presence of CTX in 9.4% of all fish samples, and the NB assay indicating toxicity in 6.8% of the fish samples. We conclude that the ELISA produces reliable and accurate results that are consistent with those provided by the accepted NB assay and that the ELISA has potential for future applications in screening fish populations for CTX. J. Clin. Lab. Anal. 22:246,253, 2008. © 2008 Wiley-Liss, Inc. [source] Pre- and postsurgical detection of IgG, IgM, and IgA specific to hydatidosis by ELISA with purified antigen enriched with the 5/B antigen complexJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 6 2002Olga Doiz Abstract An enzyme-linked immunoassay (ELISA) using purified 5/B Echinococcus enriched antigen was used to follow IgG, IgM, and IgA antibody levels pre- and posttreatment or surgical removal of hydatid cysts. The sensitivity was 97%, 37.5%, and 54.5%, respectively, and the specificity was 95.7%, 100%, and 98.9%, respectively. All isotypes could be detected 3 years after surgical removal of cysts in patients showing no remaining cyst evidence. This was especially true for IgG, which persisted in 85.2% of the patients. The data indicate that antigen purification improves specificity without affecting sensitivity, although this new antigen offers no advantages in the postsurgical monitoring of the patients. Clin. Lab. Anal. 16:295,298, 2002. © 2002 Wiley-Liss, Inc. [source] Seroprevalence of hepatitis A virus antibodies in Turkish and Moroccan children in Rotterdam,JOURNAL OF MEDICAL VIROLOGY, Issue 2 2004J.H. Richardus Abstract Seasonal fluctuations in hepatitis A have been observed in the Netherlands related to Turkish and Moroccan children after visiting their home countries. This study determined the prevalence and associated factors of hepatitis A virus (HAV) antibodies in Turkish and Moroccan children in Rotterdam. A random sample was taken of children in Rotterdam, aged 5,16 years, of Turkish and Moroccan origin, together with a random sample of native Dutch children aged 5,7 and 14,16 years. Blood was collected by finger prick on filter paper. IgG and IgM anti-HAV was detected by an enzyme-linked immunoassay (EIA). The 319 Turkish, 329 Moroccan, and 248 native Dutch children participated in the study. In Turkish children, IgG anti-HAV increased from 2.2% to 22.2% over the age groups. In Moroccan children, IgG anti-HAV increased from 10.2% to 57.7%. In native Dutch children, 0.8% had IgG anti-HAV in the youngest and 3.1% in the oldest age group. The percentage IgG-positive also having IgM anti-HAV was 21% in Turkish, and 41% in Moroccan children. No IgG-positive native Dutch children had IgM anti-HAV. The prevalence of IgG anti-HAV was associated with increased age, being Moroccan, longer stay in the country of origin before migrating to the Netherlands, and known contact to HAV. The majority of Turkish and Moroccan children aged 4,16 years in Rotterdam are not protected against HAV, but do have a high risk of becoming infected while visiting their native country. Active vaccination against HAV of these children is indicated, with as primary aim their own protection. Prevention of HAV-transmission in the general community should be seen as a secondary benefit. In addition, possible Dutch contacts of nonvaccinated Turkish and Moroccan children, such as day care workers and teachers, should also be vaccinated against HAV. J. Med. Virol. 72:197,202, 2004. © 2004 Wiley-Liss, Inc. [source] Roxithromycin inhibits transforming growth factor-, production by cultured human mesangial cellsNEPHROLOGY, Issue 6 2006HIDEAKI YAMABE SUMMARY: Background: Transforming growth factor-, (TGF-,) plays an important role in progression of renal injury. However, few materials which inhibit TGF-, have been known. Roxithromycin (ROX), macrolide antibiotics, is known to have anti-inflammatory, immunomodulatory and tissue reparative effects besides its bacteriostatic activity, although the exact mechanism of its anti-inflammatory and immunomodulatory effects was not defined. We examined the effect of ROX on production of TGF-, and type IV collagen by cultured human mesangial cells (HMC). Methods: Human mesangial cells were incubated with several concentrations of ROX and TGF-, and type IV collagen levels in the culture supernatants were measured by enzyme-linked immunoassay. Amount of TGF-, mRNA was also quantified by using a colourimetric mRNA quantification kit and semiquantitative reverse transcriptase polymerase chain reaction. We also examined the effect of ROX on tyrosine kinase, MAP kinase and NF-,B stimulated by thrombin. Results: Roxithromycin (0.1,10.0 µg/mL) inhibited TGF-, production by HMC in a dose- and time-dependent manner without inducing cell injury. ROX (10.0 µg/mL) also inhibited mRNA expression of TGF-, in HMC. Thrombin (5 U/mL) stimulated TGF-, production by HMC and ROX significantly inhibited the stimulating effect of thrombin on TGF-, production. ROX also inhibited the increment of type IV collagen production stimulated by thrombin. ROX (10.0 µg/mL) suppressed the thrombin-induced NF-,B activation, although ROX did not inhibit the activation of tyrosine kinase and MAP kinase by thrombin. Conclusion: Roxithromycin has an inhibitory effect on TGF-, production by HMC possibly via inhibition of NF-,B. ROX may be a potential agent for the treatment of glomerulosclerosis. [source] Increased arterial stiffness in children and adolescents with type 1 diabetes: no association between arterial stiffness and serum levels of adiponectinPEDIATRIC DIABETES, Issue 1 2010Angela Galler Galler A, Heitmann A, Siekmeyer W, Gelbrich G, Kapellen T, Kratzsch J, Kiess W. Increased arterial stiffness in children and adolescents with type 1 diabetes: no association between arterial stiffness and serum levels of adiponectin. Objective: Type 1 diabetes is associated with an increased risk of atherosclerosis. Adiponectin serum levels correlate inversely with cardiovascular disease in adults. The aim of this study was to examine associations between arterial stiffness indices and serum adiponectin concentrations in children and adolescents with type 1 diabetes and to study the impact of metabolic control. Subjects and methods: We evaluated arterial stiffness, distensibility, and compliance in 93 children and adolescents with type 1 diabetes and correlated the data with clinical parameters and HbA1c levels. The control group comprised 85 matched healthy children. Serum levels of adiponectin in children with diabetes were measured by enzyme-linked immunoassay and correlated with arterial stiffness indices. Results: Arterial stiffness was significantly increased in children and adolescents with type 1 diabetes (aged 13.0 ± 3.8 yr) compared with matched healthy children (p = 0.03). Arterial stiffness was elevated in males with type 1 diabetes compared with females (p = 0.023). Arterial distensibility was significantly lower in children with diabetes compared with healthy controls (p = 0.025). Arterial stiffness, distensibility, and compliance did not correlate with diabetes duration, level of HbA1c, or serum cholesterol. Adiponectin concentrations in children and adolescents with diabetes were significantly elevated compared with normal values based on gender, age, and body mass index. We found no significant associations between arterial stiffness indices and adiponectin levels in children with type 1 diabetes. Conclusions: Children and adolescents with type 1 diabetes had increased arterial stiffness and reduced arterial distensibility and arterial compliance. However, no associations between arterial functional alterations and adiponectin concentrations were seen. [source] Leukotriene synthesis during respiratory syncytial virus bronchiolitis: Influence of age and atopy,PEDIATRIC PULMONOLOGY, Issue 4 2005Giovanni Piedimonte MD Abstract Respiratory syncytial virus (RSV) infection is the most common cause of bronchiolitis in infants and an important risk factor for the development of recurrent wheezing and asthma. Cysteinyl leukotrienes were implicated in the pathophysiology of these diseases, and are being targeted for their diagnosis and therapy. We measured urinary leukotriene E4 (LTE4) in infants with RSV bronchiolitis in comparison with controls without respiratory infection, and investigated whether medical and family history, age, and passive exposure to tobacco smoke are related to urinary leukotriene excretion. We studied 33 infants with bronchiolitis and 25 controls, 1,12 months of age. Demographic and historical data were obtained from informed-consent forms and questionnaires completed by the parents. RSV was detected in nasal secretions by enzyme-linked immunoassay. Urine samples were collected on day of admission and were analyzed for LTE4 with an enzyme-linked immunoassay. Urinary LTE4 was 8-fold higher in infants with bronchiolitis than in controls. Leukotriene excretion was significantly higher in infected infants <6 months of age with a medical history of eczema or dry cough and/or family history of asthma. Multivariate analysis revealed that eczema and dry cough are independently associated with high LTE4 excretion during bronchiolitis. Exposure to tobacco smoke did not affect urinary LTE4. Our study shows that leukotriene synthesis during bronchiolitis is particularly elevated in younger infants with an atopic/asthmatic background. Urinary LTE4 may become a valuable, noninvasive marker for the identification of patients who will benefit most from therapy with leukotriene modifiers for management of bronchiolitis. Pediatr Pulmonol. © 2005 Wiley-Liss, Inc. [source] The Role of Amniotic Fluid Interleukin-6, and Cell Adhesion Molecules, Intercellular Adhesion Molecule-1 and Leukocyte Adhesion Molecule-1, in Intra-Amniotic InfectionAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2000CHAUR-DONG HSU PROBLEM: To determine amniotic fluid concentrations and correlations of interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), and leukocyte adhesion molecule-1 (LAM-1) in patients with and without intra-amniotic infection. METHOD OF STUDY: Fourteen specimens with intra-amniotic infection and 45 without intra-amniotic infection were studied. Intra-amniotic infection was defined as the presence of a positive amniotic fluid culture. Amniotic fluid IL-6, ICAM-1, and LAM-1 levels were determined by an enzyme-linked immunoassay, and normalized by amniotic fluid creatinine levels. RESULTS: Amniotic fluid concentrations of IL-6 and LAM-1 were significantly higher in patients with than without intra-amniotic infection. However, amniotic fluid ICAM-1 concentrations were not significantly different between two groups. Amniotic fluid IL-6, LAM-1, and ICAM-1 were positively correlated. CONCLUSIONS: Our data indicate that amniotic fluid IL-6 is significantly associated with an increased adhesion molecule expression in intra-amniotic infection. However, LAM-1 plays a more important role than ICAM-1 in intra-amniotic infection. [source] Lack of detection of agonist activity by antibodies to platelet-derived growth factor receptor , in a subset of normal and systemic sclerosis patient seraARTHRITIS & RHEUMATISM, Issue 4 2009Nick Loizos Objective To investigate whether agonist anti,platelet-derived growth factor receptor , (anti-PDGFR,) antibodies are present in the serum of patients with systemic sclerosis (SSc; scleroderma). Methods Sera were obtained from healthy subjects and scleroderma patients. An electrochemiluminescence binding assay was performed for detection of serum autoantibodies to PDGFR,, PDGFR,, epidermal growth factor receptor (EGFR), and colony-stimulating factor receptor 1 (CSFR1). Serum immunoglobulin was purified by protein A/G chromatography. To assess Ig agonist activity, PDGFR,-expressing cells were incubated with pure Ig and the level of receptor phosphorylation determined in an enzyme-linked immunoassay, as well as by Western blotting. Ig agonist activity was also assessed in a mitogenic assay and by MAP kinase activation in a PDGFR,-expressing cell line. Results Sera from 34.3% of the healthy subjects and 32.7% of the SSc patients contained detectable autoantibodies to PDGFR, and PDGFR,, but not EGFR or CSFR1. Purified Ig from these sera was shown to retain PDGFR binding activity and, at 200-1,000 ,g/ml, exhibited no agonist activity in a cell-based PDGFR, phosphorylation assay and did not stimulate a mitogenic response or MAP kinase activation in a PDGFR,-expressing cell line. Two purified Ig samples that were unable to bind PDGFR, did exhibit binding activity to a nonglycosylated form of PDGFR,. Conclusion Although approximately one-third of sera from scleroderma patients contained detectable autoantibodies to PDGFR, these antibodies were not specific to scleroderma, since they were also detected in a similar percentage of samples from normal subjects. PDGFR, agonist activity was not demonstrated when purified Ig from these sera was tested in cell-based assays. [source] Comparison of manual and automated ELISA methods for serum ferritin analysisJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2005Fabian Rohner Abstract Serum ferritin concentration is a sensitive measure of body iron stores. The aim of this study was to compare the performance of two commercially available enzyme-linked immunoassays (ELISAs) for serum ferritin: a widely used manual assay kit (Spectro Ferritin MT®), and a new fully automated assay (Immulite®). We analyzed serum samples from Moroccan school-aged children (n=51) from a rural area with a high prevalence of iron deficiency anemia (IDA). Four replicates of each sample were analyzed using both assays. For the manual method, the interassay repeatability was 24%, 22%, and 11%, and intraassay precision was 18.3%, 9.2%, and 9.1% at increasing serum ferritin concentrations. Using the automated assay, the interassay repeatability was 7%, 6%, and 6%, and intraassay precision was 1.5%, 5.4%, and 5.5% at increasing serum ferritin concentrations. The two assays were well correlated (y=1.16x+1.83; r=0.98). However, the limits of agreement (LOAs) were wide, particularly at low concentrations. A comparison of the assay results with recommended cutoffs for serum ferritin generated sharply different estimates of the prevalence of iron deficiency (ID) in the sample. We conclude that the automated assay has several potential advantages compared to the manual method, including better precision, less operator dependence, and faster sample through-put. J. Clin. Lab. Anal. 19:196,198, 2005. © 2005 Wiley-Liss, Inc. [source] Binding of synthetic peptides by a human monoclonal IgM with an unusual combining site structureJOURNAL OF MOLECULAR RECOGNITION, Issue 4 2001Allen B. Edmundson Abstract Using X-ray crystallography, a human monoclonal IgM cryoglobulin (Mez) was found to have an unusual combining site topography. Analysis of the unliganded Fv at 2.6,Å resolution revealed that the HCDR3 had partitioned the active site into two compartments [Ramsland PA et al. 2000. Mol. Immunol. 37: 295,310]. The two cavities had dimensions and chemical properties that were compatible with the binding of peptides. In this study, libraries of peptides were prepared using solid-phase synthesis. Binding of the intact Mez IgM to these peptides was tested by enzyme-linked immunoassays. Screening of 400 dipeptides revealed that binding was markedly skewed toward amino acids with aromatic side-chains (Phe and Trp), especially when located in the second position. Preferential recognition of aromatic side-chains by Mez IgM was confirmed with larger peptides of three to five residues, but C-terminal positioning was not favored in these peptides. Mez IgM also showed binding propensities for acidic residues (Asp and Glu) as well as several other side-chains with different chemical properties, including His, Pro, Asn and Gln. Mez IgM recognized sets of overlapping octapeptides representing the sequences of the constant domains of human IgG1 heavy chains. These peptides represented similar stretches of polypeptide on the three-dimensional structures of all three constant domains (CH1, CH2 and CH3). Thus, Mez IgM may recognize structurally homologous regions of immunoglobulin domains, which were conserved during the evolution of the immune system. Copyright © 2001 John Wiley & Sons, Ltd. [source] Familial dysautonomia: A diagnostic dilemma.PEDIATRIC PULMONOLOGY, Issue 6 2001Chronic lung disease with signs of an autoimmune disease Abstract We present an 11-year-old girl with sensory and autonomic neurological dysfunction, and respiratory insufficiency caused by recurrent aspiration. The diagnosis of familial dysautonomia (FD) was confirmed by a missing axonal flare to histamine, miosis in response to conjunctival methacholine and homozygous polymorphic linked markers DS58(18) and DS159(7) on chromosome 9. Ashkenazi Jewish descent could not be ascertained by history. A variety of positive tests for autoantibodies were initially interpreted as evidence for systemic lupus erythematosus vs. overlap syndrome with pulmonary, cerebral, skin, and ocular involvement. The diagnosis of FD was delayed because of the rarity of this disorder in Germany (second case reported). We discuss possible explanations for the misleading immunological findings, including interference by antibodies binding to milk proteins used as blocking reagents in enzyme-linked immunoassays and circulating immune-complexes due to chronic aspiration pneumonitis. Pediatr Pulmonol. 2001; 31:478,481. © 2001 Wiley-Liss, Inc. [source] | ||||||||||