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PubMed1988

Association of elastin with pseudoexfoliative material: an immunoelectron microscopic study.

Using immunoelectron microscopy, the presence of elastin and tropoelastin was demonstrated in pseudoexfoliative (PSX) material in all its classical sites on the lens capsule, ciliary non-pigment epithelium, iris epithelium and stroma, and conjunctiva. Some variability in binding affinity was seen in different sites, and labelling was more often on the periphery than the center of the PSX fibers. The elastin epitope on PSX material was more sensitive to processing than the remarkably stable epitope on mature elastic fibers. Since neither elastin nor a related component of PSX fibers, elastic microfibrillar protein, is a circulating protein, both are likely to be secreted by local ocular cells. Most of these local cells are not involved in elastogenesis normally, suggesting that an abnormal stimulus or defective regulation of matrix synthesis exists in this disease.

Actin Cytoskeleton↗
PubMed1987

[Rheumatoid factors, C-reactive protein and circulating immunocomplexes: laser-nephelometric determination using the latex aggregation method. Preliminary evaluation in rheumatoid arthritis].

C-reactive protein and rheumatoid factor assays are relevant laboratory parameters, among the most used in the clinical practice, being very useful in diagnosing and "monitoring" rheumatic diseases. A quantitative test to detect these two serum proteins is an important, more specific, new tool for clinical medicine. In our study we evaluated two new laser nephelometric assays, both quantitative, based on the agglutination of polystyrene latex particles, able to show serum concentration of CRP and RF. With a similar technique we tested the presence of circulating immune complexes. We performed our tests in a group of patients with rheumatoid arthritis, other autoimmune diseases, and healthy blood bank donors assaying simultaneously, whenever possible, the "classic" Rose-Waaler and RA tests. We found both methods easy to perform, well correlating with the semi-quantitative techniques and highly reproducible.

Antigen-Antibody Complex↗
PubMed2004

A novel method to assay proteins in blood plasma after intravenous injection of plasmid DNA.

Gene therapy is expected to lead to new and useful methods to treat diseases. The development of assays to quantitate gene-therapy-derived proteins circulating in blood will be essential to investigate the effects and side effects of the introduced proteins. The purpose of this study is to evaluate whether a protein circulating at trace concentrations in blood can be measured by tagging a peptide corresponding to glucagon residues 19-29 onto its C-terminal end. We constructed plasmids encoding chimeric proteins and transferred them into rats by hydrodynamics-based delivery. When plasmids encoding human IL8-glucagon 19-29 chimeric protein were injected into rats to evaluate the accuracy of this method, there was a high correlation between chimeric proteins measured by an enzyme-linked immunosorbent assay for human IL8 and one by a radioimmunoassay for glucagon. Furthermore, when plasmids coding rat IFN gamma receptor IgG-Fc glucagon 19-29 chimeric protein were injected to evaluate the time course of chimeric proteins in blood plasma, we could calculate the concentrations in blood from 10 microl plasma samples using glucagon 19-29 tag as follows: 2815+/-2318 ng/ml after 4 hours (mean+/-s.D.), 6061+/-2789 ng/ml after 8 hours, 5752+/-2270 ng/ml after 12 hours, 2870+/-1062 ng/ml after one day, 1440+/-334 ng/ml after three days, 1120+/-433 ng/ml after seven days, and 281+/-162 ng/ml after 16 days. Blood sugar levels which might have been increased by glucagon did not increase even at peak chime- ric protein concentrations. These results demonstrate a useful and convenient method to assay gene therapy products circulating in blood using a glucagon 19-29 tagging vector.

Animals↗
PubMed1999

In vitro interaction of serum protein with circulating DNA of lung cancer patient.

Circulating DNA and oncoproteins can be extracted from serum or plasma of cancer patients. In this study, using gel retardation analysis we observed circulating DNA obtained from plasma of a lung cancer patient complexed with serum proteins. p53 was identified by immunoblotting as one of the proteins present in the complex. Our finding suggests that the same interaction observed between p53 and DNA in intact cells occurs in serum of lung cancer patient. As far as we know this is the first evidence for such finding.

Aged↗
PubMed1981

Pregnancy-associated plasma protein A: circulating levels during normal pregnancy.

The development of specific and sensitive electroimmunoassays for a recently identified high molecular weight alpha-2 mobile pregnancy-specific protein (pregnancy-associated plasma protein A, PAPP-A or SP4) is described. These assays have permitted the detection of circulating levels of PAPP-A (10 microgram/L) as early as the fifth week of pregnancy. In all 18 subjects studied, the levels of PAPP-A rose from first detection in the first trimester until delivery at term. The development of these assays now permit the evaluation of PAPP-A measurement as a diagnostic test of early pregnancy and as an index of fetal well-being throughout gestation.

Female↗
PubMed1990

Plasma clearance of chicken and human insulin-like growth factor-I and their association with circulating binding proteins in chickens.

We have investigated the clearance of 125I-labelled chicken and recombinant human insulin-like growth factor-I (IGF-I) from the circulation of chickens as well as the role that IGF-binding proteins play in this process. Analysis of plasma samples by high-performance liquid chromatography (HPLC) neutral gel permeation on a TSK G3000SW column indicated that the i.v. injected radioactivity was rapidly partitioned between at least three pools. Most of the radioactivity occurred in a complex with binding protein(s), while smaller amounts of radioactivity chromatographed in the free IGF-I peak or appeared as low molecular weight degradation products. The labelled chicken and human IGF-I were rapidly cleared during the first 90 min. The calculated half-life for total labelled IGF-I during this period was 54 min for the chicken tracer and 33 min for the human tracer. The clearance was monitored for 10 h during which the human tracer continued to be cleared more rapidly than the chicken tracer. The proportion of radioactivity appearing as low molecular weight degradation products increased with time. Acid gel permeation and reverse-phase HPLC of the binding protein-associated radioactivity demonstrated that the labelled IGF-I bound was intact IGF-I. Sephadex G-200 gel permeation chromatography of chicken plasma samples at pH 7 x 4 showed that the binding protein complex labelled in vivo with chicken IGF-I tracer had a molecular mass of 55 kDa. Furthermore, the tracer associated with the binding protein coeluted with the major peak of endogenous IGF-I, suggesting that the tracer was bound to the physiologically relevant binding protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Associations between C-reactive protein and circulating cell adhesion molecules in patients with unstable angina undergoing coronary intervention and their clinical implication.

BACKGROUND: There is growing evidence that C-reactive protein (CRP) may have a direct role in the pathogenesis of atherosclerosis. HYPOTHESIS: The purpose of this study was to assess associations between CRP and adhesion molecules and to determine the prognostic value of adhesion molecules as a predictor of cardiac events in patients with unstable angina. METHODS: Fifty-five consecutive patients (33 males, mean age 61 years) with unstable angina (Braunwald class IIb or IIIb) undergoing coronary stenting were included in this study. RESULTS: The test for a trend toward increasing intercellular adhesion molecule (ICAM)-1 concentrations by the 75th percentile of CRP levels at 72 h after coronary stenting was significant (p = 0.03). At 72 h after coronary stenting, CRP levels were the only determinants of ICAM-1 concentrations by multiple linear regression analysis. An elevated level of CRP (>5.4 mg/l) (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.3-3.7, p < 0.05) and ICAM-1 (>321 ng/ml) (OR 1.2, 95% CI 1.1-2.1, p < 0.05) at 72 h after coronary stenting is an independent risk factor for an adverse cardiac event. CONCLUSIONS: These results suggest that in patients with unstable angina undergoing coronary stenting, the measurements of inflammatory parameters, especially CRP and ICAM-1, may be useful for identifying those at higher risk of a cardiac event, and CRP may play a direct role in promoting the inflammatory component of atherosclerosis by inducing significant expression of ICAM-1.

Aged↗
PubMed2003

Lipid and protein oxidation contribute to a prothrombotic state in patients with type 2 diabetes mellitus.

Diabetes mellitus (DM) is associated with enhanced lipid oxidation and persistent platelet activation. We investigated whether oxidant stress (OS) also affects circulating proteins and is associated with an abnormal coagulative pattern. In 72 type 2 DM (T2DM) patients, urinary 8-iso-prostaglandin (PG) F2alpha and 11-dehydro-thromboxane B2 (TXM) were measured as markers of lipid peroxidation and platelet activation, respectively. The carbonyl content of plasma proteins (PCARB) was measured as global index of protein oxidation. 8-Iso-PGF2alpha and PCARB levels were higher in DM patients than in controls (P < 0.05). Likewise, both TXM and prothrombin F1+2 levels were higher in diabetics (P < 0.05). By contrast, anticoagulant markers, such as activated protein C, protein C activation peptide, and soluble thrombomodulin (TM) were depressed in T2DM (P < 0.05). In conclusion, OS in T2DM involves circulating proteins and is associated with an unbalanced promotion of procoagulant reactions. These effects in concert with platelet activation may contribute to atherothrombotic complications in T2DM.

Aged↗
PubMed1991

Analysis of viral proteins in circulating immune complexes from chronic carriers of hepatitis B virus.

Sera from 54 children (mean age 5.8 years) with chronic hepatitis B virus (HBV) infection were investigated for the presence of immune complexes containing HBV proteins. Clinical diagnosis was established by histology and biochemical markers and included chronic persistent (36 cases) or chronic aggressive (seven) hepatitis, liver cirrhosis (six) and HBV-mediated membranous glomerulonephritis (five). Circulating immune complexes were precipitated with 2.5% polyethylene glycol and analysed by immune blot using monoclonal antibodies against S, pre-S2 glycopeptide, pre-S1 and HBe/c epitopes. All sera, including those from 11 healthy HBV-negative blood donors contained PEG-precipitable substances, but the amount of precipitate did not correlate with the presence or amount of HBV proteins. The great majority (36 out of 40) of HBeAg-positive patients contained HBs proteins in immune complexes, but no detectable HBe protein. The immune complexes usually contained more pre-S1 than the free HBsAg particles from the same patient. The precipitates of anti-HBe-positive patients rarely contained HBV proteins (two out of 14) and, if so, in low amounts. During follow up of six patients we found that high levels of HBs-containing immune complexes may be correlated with subsequent elimination of HBV. This elimination is possibly initiated by binding of anti-pre-S1 antibodies to HBV and HBs particles.

Antigen-Antibody Complex↗
PubMedDate not supplied

[Circulating blood plasma proteins during the infusion therapy of blood loss].

Experiments were conducted on 60 dogs to study the total protein level in circulation after acute and prolonged blood loss and infusion of salt and colloid solutions. It was found that the amount of circulating blood in the restorative period depends mainly on the individual initial values and to a lesser degree on the protein loss. A low protein level persists in infusion therapy. Infusion of colloid solutions inhibits mobilization of plasma protein reserve into the vascular channel as compared to that in infusion of salt solutions. The authors revealed two types of reactive changes in circulating protein in the restorative period after blood loss and infusion therapy.

Acute Disease↗
PubMed1994

Relationships between protein carbonyls, retinol and tocopherols level in human plasma.

Free radical oxidation has been claimed as one of the most important mechanism of damage in aging and in several diseases. Carbonyl content in tissue and circulating proteins is a stable marker of this attack. In 29 apparently healthy subjects (25-89 years old) carbonyl content of plasma proteins and retinol and tocopherols (alpha- and gamma-) were studied. Carbonyls level did not show an increase with age. A good correlation between carbonyls content and gamma-tocopherol (r = 0.44, P < 0.05) and a trend with retinol (r = 0.34, P = 0.07) was found, but not with alpha-tocopherol. An inverse correlation was observed between carbonyls and plasma proteins (r = -0.63, P < 0.01) and the natural antioxidant studied showed an increase with age and a good relationship with lipids. These data suggest that retinol and tocopherols, well known scavengers of free radicals, are involved, at least partially, in the prevention of oxidative damage of circulating proteins.

Adult↗
PubMed2005

Serum C-reactive protein and circulating endothelial cells in patients with acute myocardial infarction.

As an in vivo indicator of vascular injuries, circulating endothelial cells (CECs) have been used as a marker of endothelial damage in a variety of vascular disorders. C-reactive protein (CRP) is a sensitive indicator of inflammation. To investigate the presence of CECs in patients with acute myocardial infarction (AMI) and to evaluate their clinical associations and possible relationship with infection, CECs from peripheral blood were isolated by using immunomagnetic beads coated with antibodies against CD146. Their endothelial origin was confirmed by the positive labeling of von Willebrand Factor (vWF), CD31 and electron microscope. Results showed that CECs number and CRP level were 52 (28-81.5) cell/ml, 7.98+/-2.25 mg/l and 10.5 (6-16.5) cell/ml, 1.41+/-2.05 mg/l in AMI patients (n=37) and health controls (n=42) respectively (p<0.001). The apoptosis rate and necrotic rate of CECs in AMI were 25% and 19%, respectively. Correlation analysis revealed a significant positive correlation between CECs and CRP (r=0.505, p=0.001). CECs numbers did not correlate with age, gender, serum cholesterol, hypertension, obesity, history of cardiovascular disease, or smoking. These results suggest a strong correlation between level of CRP and counts of CECs in patients with AMI. The number of CECs and CRP may be combined to reflecting the endothelial cell injury.

Antigens, CD↗
PubMed1997

Soluble low density lipoprotein receptor-related protein (LRP) circulates in human plasma.

Our studies have identified a soluble molecule in normal human plasma and serum with the characteristics of the alpha-chain of the low density lipoprotein receptor-related protein (LRP). LRP is a large multifunctional receptor mediating the clearance of diverse ligands, including selected lipoproteins, various protease inhibitor complexes, and thrombospondin. A soluble molecule (sLRP) has been isolated from plasma using an affinity matrix coupled with methylamine-activated alpha2-macroglobulin, the ligand uniquely recognized by LRP, and eluted with EDTA. This eluate contains a protein that co-migrates on SDS-polyacrylamide gel electrophoresis with authentic human placental LRP alpha-chain, is recognized by anti-LRP alpha-chain monoclonal antibodies, and binds the 39-kDa receptor-associated protein (RAP) and tissue plasminogen activator-inhibitor complexes. A similar RAP-binding molecule was detected in medium conditioned for 24 h by primary cultures of rat hepatocytes, suggesting that the liver may be the in vivo source of sLRP. In contrast, immunoprecipitation experiments failed to detect the production of sLRP by cultured HepG2 hepatoma and primary human fibroblast cells. Addition of a soluble form of LRP to cultured HepG2 cells resulted in a significant inhibition of capacity of these cells to degrade tPA, a process that has been demonstrated to be mediated by cell surface LRP. Preliminary data indicate that the concentration of sLRP is altered in the plasma of patients with liver disease. Increased levels of sLRP may antagonize the clearance of ligands by cell bound LRP perturbing diverse processes including lipid metabolism, cell migration and extracellular proteinase activity.

Animals↗
PubMed1968

Association of C-reactive protein and circulating leukocytes with resistance to Staphylococcus aureus infection in endotoxin-treated mice and rabbits.

The response of rabbits and mice to treatment with Escherichia coli endotoxin, as measured by C-reactive protein (CRP) and leukocyte levels, and resistance to Staphylococcus aureus infection was studied to evaluate the significance of these responses and their associations. In both species, there was an initial leukopenia without early recovery of normal lymphocyte levels. This was followed by an increase in polymorphonuclear leukocytes and a return to near the normal range. The CRP level was slightly altered during the stage of decreased resistance and increased throughout the remainder of the period of observation. The resistance level was decreased initially, recovered to normal levels, and continued to increase. The changes in CRP and resistance levels were closely associated. It would appear that this association between CRP and resistance, the antibacterial activity of CRP, and its action on the polysaccharides obtained from bacterial cell walls are evidence for the participation of CRP in nonspecific resistance to infection.

Animals↗
PubMed1981

Autoimmunity in selective IgA deficiency: relationship to anti-bovine protein antibodies, circulating immune complexes and clinical disease.

To test the possibility that autoimmunity could be related to increased levels of anti-bovine antibodies and/or circulating immune complexes in selective IgA deficiency, we studied the sera of 30 consecutive patients for the quantitative level of antibody to bovine milk, the presence of antigen--antibody complexes and 10 selected autoantibodies. Higher titres of anti-milk antibody and circulating immune complexes were to be correlated with positive serological tests of autoimmunity in these patients, and rheumatoid arthritis (three cases) and neurological disease (four cases) were found in individuals who had both milk precipitins and circulating immune complexes. We suggest that the chronic excessive permeability of the gastrointestinal tract in selective IgA deficiency may permit the excessive absorption of many food proteins, leading to the formation of antigen--antibody complexes and autoimmunity.

Adolescent↗
PubMed1996

Circulating immunostimulatory protein 90K and soluble interleukin-2-receptor in human ovarian cancer.

The tumor-associated antigen 90K is thought to play an important role in cellular immune defense against malignant cells. It is therefore of interest to investigate whether circulating 90K could be used as a prognostic variable in ovarian cancer, and whether this immunostimulatory antigen is related to other parameters known to be involved in the cellular immune response. In the present retrospective study, circulating levels of antigen 90K were measured before primary surgery in 152 ovarian-cancer patients. A very close association between antigen 90K and s-IL-2R concentrations was pointed out in a stepwise logistic regression model. Univariate analysis of overall survival revealed that antigen 90K and s-IL-2R were associated with poor prognosis. In the multivariate Cox regression, however, neither antigen 90K nor s-IL-2R retained independent prognostic significance. Urinary neopterin was shown to be the only independent prognostic variable among the "immunological parameters" investigated. Additionally, residual disease after primary tumor debulking and histopathologic tumor grade were the most prominent clinico-pathologic parameters for the independent prediction of poor clinical outcome in ovarian-cancer patients.

Adult↗
PubMed1983

The use of PFC exchange transfused rats in studies of lung microvascular permeability.

The fluorocarbon exchange transfused rat was used to examine the effect of varying concentrations of circulating proteins on the permeability of pulmonary endothelium to inject ferritin. There is a significant inverse relationship between protein concentration and the relative number of vesicles containing ferritin as well as the amount of ferritin in the basement membrane. A hysteresis effect of the amount of circulating protein on the permeability of endothelium to ferritin was noted. In repletion experiments almost 2.5 times more protein was required to maintain capillary permeability at normal levels than during depletion experiments.

Animals↗
PubMed1997

A recombinant tumor necrosis factor-alpha p80 receptor:Fc fusion protein decreases circulating bioactive tumor necrosis factor-alpha but not lung injury or mortality during immunosuppression-related gram-negative bacteremia.

PURPOSE: During gram-negative bacteremia (GNB), tumor necrosis factor-alpha (TNF-alpha) is a critical early mediator of host defense, whose overexpression can initiate acute lung injury, multiple organ failure, and death. In this study we evaluated the ability of a chimeric fusion protein containing two extracellular domains of the human p80 TNF-alpha receptor and the Fc region of human IgG1 (TNFR:Fc) to reduce circulating TNF-alpha, and to ameliorate organ injury and improve survival in a rodent model of GNB during immunosuppression-related neutropenia. MATERIALS AND METHODS: Conscious catheterized male rats (n = 37) with stable cyclophosphamide-induced neutropenia were infected intravenously (i.v.) with 5 x 10(9) live Escherichia coli (EC, serotype O55:B5) ending at t = 0. All animals received antibiotics (penicillin/ amikacin sulfate) at t = 0.5 and t = 8 hours, and 0.9% sodium chloride (normal saline solution (NS), 1 mL/h) from t = 0 to 8 hours. Subgroups were post-treated at t = 0.5 hours with a 1.0 mL i.v. dose of TNFR:Fc (60, 600, or 1,200 micrograms; Immunex), 600 micrograms of human IgG1-kappa or IgG1-lambda (Sigma), or NS alone (controls). A separate TNFR:Fc pretreatment subgroup received 600 micrograms/rat of the fusion protein 5 minutes before starting EC infusion. Hemodynamics were monitored continuously through t = 24 hours, and arterial samples were collected at baseline and at t = 1.5, 4.5, 8, and 24 hours after EC were analyzed for blood gases, quantitative culture, serum endotoxin, bioactive and antigenic TNF-alpha, and formed elements. Postmortem tissues were examined for histopathologic changes. RESULTS: Compared with antibiotic-treated and fluid-supported controls, TNFR:Fc dose-dependently reduced bioactive but not antigenic TNF-alpha without altering bacterial clearance, serum endotoxin, or 24-hour survival. Of note, 600 micrograms of IgG1-kappa or IgG1-lambda attenuated peak bioactive TNF-alpha to a similar degree as 1,200 micrograms TNFR:Fc, and also significantly reduced serum endotoxin levels. Nevertheless, by t = 8 hours all bacteremic rats were hypothermic with tachypnea-related hypocarbia and hyperoxemia and were thrombocytopenic. At death, all subgroups showed similar hepatic glycogen depletion and pulmonary congestion with perivascular edema and alveolar hemorrhage. CONCLUSIONS: Although TNFR:Fc and its idiotypic control IgG1 reduced circulating bioactive TNF-alpha, neither treatment prevented progression of lethal shock with attendant organ injury in this conscious, antibiotic-treated and fluid-resuscitated model of immunosuppression-related GNB.

Animals↗